t
r-u T DYE
Chap. !• • •
Of Colours, of oxygen on bodies Is greatly promoted m particular
^c. circumftances. With the afliftance of heat, almoft all
V^v coloured bodies are decompofed by means of oxygen.
•At the temperature, of 448°, ™heat flour is deprived
of its white colour, becomes firft brown, and then
changes to black. The oxygen enters into combina¬
tion with the hvdrogen, one of the component parts ot
the vegetable matter, and in this ftate it is driven off.
The adlion of light produces effefts fimilar to thofe ot
heat. A decompofition of the colouring matter takes
place by means of the light to which the body is ex-
pofed ; and one of its component parts combines with
oxygen. The effeds of light on the colour of wood
have been long obferved. Wood kept in the dark re¬
tains its natural appearance j but when it is expoied to
the light it becomes yellow, brown, or of lome other
(hade. This effeft is found to be fubjed to confider-
able variations in different kinds of wood, and bears
fome proportion to the intenfity of the light. If the
folution of the green part of vegetables m alcohol,
which is of a fine green colour, be expofed to the light of
the fun, it very foon affumes an olive hue, and in the
courfe of a few minutes it is entirely deprived of its
colour. When the light is weak the change proceeds
more flowly •, and if it be kept in the dark no change
whatever takes place j at leaft it requires a great length
of time. Light feems to favour the tendency to de-
compofition in many bodies, by producing combinations
of fome of their conftituent principles, as when water
is formed by the union of oxygen and hydrogen, or
carbonic acid by the union of carbone and oxygen.
Some bodies even are deprived of the whole or
part of their oxygen by the adion^of light. Oxymu-
riatic acid expofed to the light, becomes common mu¬
riatic acid by lofing its oxygen 5 and the nitrate of di¬
ver becomes black by a partial decompofition aud lois
of its oxygen. , . , r
55. Such then feem to be the moil general cauies,
the adion of which produces changes in the colour of
coloured bodies. It is either by the decompofition ot
the fubftances, in confequence of new compounds form¬
ed by the combination of fome of the conflituent parts ,
by fome of thefe parts combining with oxygen *, or by
the addition or abftradion of oxygen. And to fuch
changes colouring matters muft be fubjefted from their
compound nature; fince they are molt generally derived
from animal or vegetable fubftances. d he ieledion of
fuch fubftances as refift the adion of thefe caufes, muff
therefore be an objett of the greateft importance in
the art of dyeing. A colour too which is fuihciently
permanent ought to be fuch as will refift the adion of
acids, alkalies, foap, and other lubftances to which
dyed cloth may be expofed.
M thod of 56- There is a great difference in colours with re¬
proving the gard to their power of refitting the adion of air and
pejrma- light j and as it is in this that their permanency chiehy
• nency of a ConfiftSj independent of their luttre, it becomes an ob-
<ulour' jed of great importance, to be able to afeertain by
eafy tefts the durability or goodnefs of any colour. In
France, where the art of dyeing was more under the
regulation of government than in other countries, and
a diftindion was eftabliftied by law between dyers of
durable and fading colours, the means or afcertaining
the permanency of colours became of ftill greater con¬
fequence. For ihe dyer of fading colours was lubjed
Vol. VII. Fart II.
I N G.
to punifirment if he produced colours which were too Of Colours,
permanent 5 fo rigorous and capricious were the laws ,   ,
which regulated thefe matters. 1 he obfervations of
Mr Dufay on this fubjed laid the foundation of the re¬
gulations which were made to afeertain this point.
For this purpofe he made experiments by dyeing wool
of all colours, with all kinds of colouring matters -, and
fetting entirely afide the prejudices of the dyers, he
colleded moft of the fubftances which he fuppoled
might be employed in the art, and tried a great num¬
ber of them, inveftigating their good or bad qualities
Fits firft experiments were made on woollen yarn •,Dufay s.
but finding afterwards that pieces of white cloth were
more fuitable to the purpofe, he employed them. And.
that he might diftinguifh between permanent and fad¬
ing colours, he expofed to the adion of the fun and air
for the fpace of twelve days, patterns of all colours
which he had dyed with known fubftances. In this
time durable colours were little injured, but thole
which were of a fading nature were almoft entirely
obliterated. But as the adion of the fun might be
lefs intenfe in cloudy weather, and thus the left would
be leis fevere when that happened than during twelve
days of bright funfhine ; to obviate this inconvenience
and uncertainty, he feleded one of the worft colours,
that is, one on which the fun had the greateft effect
in the fame time. This colour ferved as a ftandard m
his experiments 5 and whenever he expofed fluffs to the
air to prove the colour, he expofed a piece of this fluff
along with them. He did not calculate by the
ber of days, but by the change on the colour of the
ftandard fluff. For he kept the pattern expofed to the
air till it had loft as much as the ftandard would
have done by the adion of the fun during twelve
days in fummer. He found from thefe experiments
that it required four or five days longer in winter than
in fummer to produce the fame effed. ^
58. $ut by this method of expofure to the air he
had another objed in view. This was to difeover the
proper proof for each colour. By the application of
thifr proof a fluff is tried whether its colour be perma¬
nent or not. The pattern for inftance is boiled with
alum, tartar, foap, vinegar, See. and by the effed.
of thefe fubftances its quality is afeertamed. But
from the component parts of the fubftances employed
being then unknown, and the imperfed ftate of chemi¬
cal fcience, thefe proofs muft appear now to have been
extremely precarious and infufficient. Some which
were applied, from their natural effeds, deftroyed good
colours, and produced no effed whatever on bad
colours. . n. ,
59. As the method he employed may fuggeft the
means of difeovering others founded on more coned
principles and more accurate knowledge of the fubftan¬
ces w’hofe adion is inveftigated, we (hall mention the
ingenious procefs which he followed. Having obferv¬
ed the effeds of air and light on each colour, whether
it were a good or bad colour} he tried the fame fluff
with different proofs, and flopped as foon as he difeo-
vered one which produced the fame effeds as the air.
He then noted the weight of the ingredients the
quantity of water, and the length of time j and thus
he was certain of producing on a colour an effed fimi-
lar to that which the air would have produced, on the
3 E fuppofition
40® DYE
Of Colours, fuppofition that it was dyed in the fame way with his,
. &cc' as was the cafe in France where all the proceffes were
then regulated by law. In this way he w as enabled to
afcertain the qualities of any colour, by making an ana-
lyfis of the ingredients of which it was compofed. By
means of the proofs w'hich urere invented by this ingeni¬
ous chemift, as much of a colour which was not of a du¬
rable nature, could be difcharged in a few minutes, as
would be loft by the action of the air and light in twelve
or fifteen days. But as general rules framed for fuch
trials are liable to many exceptions, from different un¬
avoidable caufes, their application in many cafes may
be confidered as too fevere. For inftance, light co¬
lours require lefs adive proofs than thole which are of
a deeper dye, and are more loaded with colouring
matter ; in the latter cafe, a confiderable proportion of
colouring fubftance may be carried off w ithout much
vifible change on the colour j but in the former, by
means of the fame adive teft, the colour would be en¬
tirely obliterated. Every variety of lhade, therefore,
would have required a feparate proof. The fun and
the air muft always be confidered as the true teft •, and
thofe colours which undergo no change in a certain
time by this expofure, may be confidered permanent
colours, although they may be greatly changed by the
application of proofs. Scarlet, which is dyed with co¬
chineal alone, affumes a purple colour when tried by
means of alum : but if fcarlet be expofed to the fun, it
lofes fome of its brightnefs, and becomes of a deeper
fhade ; but this lhade is different from that which is
produced by alum. In certain cafes then the fame ef-
fed is not to be expeded from the adion of proofs and
that of air and light.
Hellot’f. 60. An experiment by Hellot is added as a farther illuf-
tration of a colour refilling the effeds of expofure to the
air, and yet being deftroyed by the adion of other fub-
ftances. Brazil wrood, he mentions, like other woods
loaded with colour, produces a fading dye. With this
he prepared a red, much finer than madder reds, and as
bright as thofe made with kermes. This red was ex¬
pofed to the air for the two laft months of the year
1740, in which much rain fell, and for the two firft
of 1741 ; and notwithftanding the rain and bad wea¬
ther, it was fo far from lofing, that it gained body.
Yet this red, fo durable in the air, is incapable of re¬
filling the trial by tartar. Colours then may be rec¬
koned fufficiently durable when they refill the effeds
of the air, although they are decompofed or dellroyed
by means of powerful chemical agents. From thefe
obfervations, it is therefore obvious, that the only fure
mode of afeertaining the permanency of colours, is by
expofing the dyed Huffs for a certain length of time to
the adion of light and air.
Berthol- * Berthollet * propofes to employ the oxygenated
let’s. muriatic acid as a quick and eafy method of afeertain-
* El*m. of ing the degree of durability which a colour may pof-
Dyeing, fefs . becaufe it ads like the air itfelf. When a trial
l8®* is to be made on any piece of fluff, all that is neceffary
is to put a pattern of it into the acid, along with one
of a fluff which is known to have been dyed proper¬
ly. The relative power of refilling its adion, which
appears in the two patterns, becomes the teft or mea-
fure of the quality of the colour. This liquor having
a very powerful adion on the colouring particles, mull
be employed in a very diluted ftate. In the ufe of this
1 N G. Parti.
proof, it is attended with the advantage of exhibiting Of Colours,
nearly the ftiades and changes through which a Huff &c-
muft pafs when it comes to be aded on by the air. *
Still, however, the fame philofopher adds, the oxygen¬
ated muriatic acid is not to be confidered as an infalli¬
ble teft •, entire confidence can only be placed in the
refults obtained by the adion of the air and light.
62. To prove the colours of filk, it has been thought Teft for
fufficient to expofe them to heat in acetous acid or le-filk.
mon juice j and thofe colours which Hand this teft are
confidered as permanent. When the colours have been
obtained from the woods or archil alone, they are red¬
dened by means of 3 vegetable acid ; but if the folu-
tion of tin has been ufed to dye with thofe fubftances,
the colour which has been prepared in an acid liquor
fuffers no change from vegetable acids. Thus the
colour which is the lead expenfive in the preparation
may be reckoned good by the teft, although it will
prove the leal! permanent. For filk therefore, the oxy¬
genated muriatic acid Iliould be employed $ but more
elpecially expofure to the air.
*63. It muft appear an objed of much importance For dye
to the dyer to be able to eftimate the relative qualities
of colouring fubftances of the fame kind. The oxv-
genated muriatic acid may alfo be employed as a tell
for this purpofe. By its ufe we may afcertain the pro¬
portional quantity of colouring matter in thofe fub¬
ftances, the nature of whole colouring particles is the
fame j as, for inftance, when different parcels of indi¬
go are to be compared together. In this Cafe no fo¬
reign affinity can interrupt the adion of the acid. And
even if it Ihould happen, that any confiderable differ¬
ence exifts in the nature of colouring particles fup-
pofed to be the fame, the adion of this acid, it is pro¬
bable, would Hill be a meafure of their comparative
goodnefs. If then it is propofed to compare together
two or more colouring fubftances of the fame nature,
and to afcertain the relative quantity and quality of
the colouring particles in each, all that is neceffary
is to compare the quantities of the fame oxygenated
muriatic acid which is required to produce the fame
degree of change in equal weights of each. For the
qualities of thefe fubftances, or the quantities of co¬
louring particles they contain, are diredly proportional
to the quantities of liquor required to produce the
fame effed on each. In conduding this experiment
it is fcarcely neceffary to obferve, that the colouring
matter of each fubftance Ihould be diffolved in a pro¬
per liquor, and that all the circumftances attending
the comparifon fliould be as nearly as poffible the
fame.
64. If different kinds of indigo are to be compared indigo
together, let an equal w-eight of each be carefully
powdered, and introduced into feparate matraffes with
eight times their weight of concentrated fulphuric
acid, and let them remain for 24 hours in a heat of
from ioo° to 120° Fahrenheit. Each folution is then
to be diluted with water, and filtered. What remains
on the filter is to be colleded, ground in a glafs mor¬
tar, and again digefted with a little more fulphuric
acid. Thefe laft folutions are then to be diluted with
equal quantities of water, filtered and added to its cor-
refponding liquor. As much oxygenated muriatic
acid is then to be added to each folution as will dif-
charge the colour, or bring them to a ftiade of yel-
• low
Chap. II. DYE
Of Mor- low: Thus the qualities of the different kinds of in-
dants. digo may be afcertained by the quantity of oxygenated
muriatic acid which is required to difcharge their co¬
lour.
65. The procefs is more fimple to compare the qua¬
lities of thofe colouiing matters which are foluble in
water. To equal bulks of the deco&ion, containing
the fame weight of each fubftance, the oxygenated mu¬
riatic acid is added till they are all brought to the
fame (hade •, and the quality of the fubftance is pro¬
portionate to the quantity of acid required.
Chap. II. Of Mordants.
66. The term mordant, derived from the French
word mordre, to bite or corrode, is applied to thofe
fubftances which are employed in dyeing, to facilitate
or modify the combination of the colouring particles
with the fluff. This name was given to thefe fub¬
ftances, from a fuppoied mechanical aftion which they
produced on the fubftance to which the colour was
communicated; and as no equivalent word has yet
been propofed, the original is retained in the Englifh
language.
Importance 67. The knowledge of this clafs of fubftances is
of mor- not lefs important in the art of dyeing than that of
dants. colouring matters themfelves, becaufe on their action
depend the variety, brightnefs, and durability of co¬
lours. The adlion of mordants is undoubtedly owing
to chemical changes, fo that more extenfive obferva-
tion and a complete knowledge of their effe&s, muft
greatly contribute to the improvement and perfection
of the art of dyeing. It is by a new feries of attrac¬
tions which are introduced by their action, that the
colouring particles are combined with the fluff, arid
the qualities and degrees of the colours are affeCted.
68. A mordant is not always to be confidered as a
fimple agent j for, of the different ingredients which
enter into its compofition, new combinations are fome-
times formed, fo that the fubftances which are imme¬
diately employed, are not the direCt agents in ef¬
fecting the changes, but the new compounds which are
produced.
Mo le of 69. Mordants are applied in different ways, accord-
application. *ng to their nature, according to the nature of the co¬
louring matter, and that of the fluff to be dyed.
Sometimes they are mixed with the colouring parti¬
cles, and fometimes the fluffs to which the colour is to
be communicated, are impregnated with them j and
fometimes both thefe proceffes are combined. In fome
of the more complicated operations of dyeing, fub¬
ftances are fucceflively applied to fluffs in which the
aCtion of the laft only produces the effeCt. In fuch
cafes, there is a gradual progrefs of combination ; but
it is only by the effeCt of the laft compound which is
formed, that the colour is evolved.
Illuftrated 7°* effe^s mordants are well illuftrated in
many of the proceffes which are followed in the art of
printing linen j and for the illuftration of thefe effects,
we {hall extract from Berthollet a fliort account of
fome of thefe proceffes. For linens to which it is pro¬
pofed to give different (hades of red, the mordant em¬
ployed is prepared by diffolving in eight pounds of hot
water, three pounds of alum, and one pound of ace¬
tate of lead, or fugar of lead. To this folution twTo
I N G. 403
ounces of potato, and afterwards twi) ounce's of pow- Of Mor-
dered chalk, are to be added. Our chemical readers,
will readily perceive, that the firft change which takes
place is the decompofition of the alum, by means of
the acetate of lead. The oxide of lead combines with
the acid of the alum, and forms an infoluble fait,
which is precipitated. The alumina which conflitutes
the bafe of the alum, unites with the acetous acid,
and forms an acetate of alumina. The chalk and pot-
afh, according to Berthollet, ferve to faturate the ex-
cefs of acid ; but it feems more probable that the ad¬
dition of thefe fubftances is found neceffary, on ac¬
count of new decompofitions which are effected by
their action. Several advantages arife from the forma¬
tion of the acetate of alumina, in the future changes
which are to be effe£ted. The alumina, or earthy
bafts of this fait, is retained in combination with the
acid, by a much weaker affinity than wThen combined
with fulphuric acid in the ftate of alum. Its affinity
being thus weakened, it.is more eafily decompofed,
and unites more readily with the (tuff and colouring
particles. Another advantage not lefs important is,
that the effeft of the acetous acid on the colouring
matter being lefs powerful than the fulphuric acid, the
acid liquor which remains after the feparation of the
alumina, does not produce fuch hurtful effects. And
befides, as the acetate of alumina does not cryftallize,
the mordant which is thickened with ftarch or gum,
to prepare it for.being applied to the block on which
the defign is engraved, retains the fame uniform con¬
fluence, which would not be the cafe if it contained
alum, the latter being difpofed to cryftallize.
71. Let us now trace the different fleps of the ope¬
ration in printing a piece of cloth. When it has been
impregnated with the mordant, in the manner deter¬
mined by the defign, it is immerfed into a madder
bath. Thus the whole of the cloth is coloured •, but
the colours are deeper on thofe parts to which the
mordant has been communicated *, becaufe in thofe
parts the colouring particles of the madder have en¬
tered into combination with the alumina and the fluff
forming a triple compound. The acetous acid fe-
parated from its earthy bails remains in the bath.
72. The effeft of external agents on the colouring
particles in this ftate of combination is much lefs con-
fiderable than when they are in a feparate Hate, or
only combined with the fluff, without the intermediate
adtion of another fubftance. It is on this property
that the fubfequent operations depend. Having been
immerfed in the madder-bath, the cloth is afterwards
boiled with bran, and expofed to the open air by
fpreading it out on the grafs ; and the ultimate repe¬
tition of thefe operations is continued till the ground
is whitened. The colouring particles of the madder
which have not come in contadl with the alumina are
completely changed by entering into new combina¬
tions; while thofe which have united with it remain
unaltered in confequence of the ftronger affinity, fo that
thofe parts of the cloth which have been impregnated
with the mordant, retain the colour and exhibit the
defign.
73. The decompofition of the colouring particles by
boiling the fluff with bran, and expofure to the air,
feems to be effedted in a manner fimilar to the deftruc-
tion of the colouring matter of flax, and is to be ac-
3 E 2 counted
4o4
Of Mor.
dants.
DYE
counted for in the fame way. In the procefs of bleach¬
ing, indeed, alkaline fubftances are employed. But
for the purpofe of difcharging the fuperfluous colouring-
matter from printed cloths, bran is preferred as a fub-
flitute } becaufe part of the colouring-matter, even
when fixed by alumina, would be deitroyed by the
ftronger action of alkalies ; but as the action of the
bran is much weaker, it aflPefts only the colouring par¬
ticles which have not come in contact with the alumi¬
na, and which by the a£lion of the air are diipofed to
undergo a more eafy folution.
74. Let us take another example with a different
mordant. If, inftead of alum, a folution of iron, as
the acetate of iron, be employed, fimilar phenomena
are exhibited. The folution of iron is decompofed by
the particles of colouring-matter, and a triple com¬
pound is thus formed of the colouring-matter, the
oxide of iron, and the Huff. But when this mordant is
employed, a great variety of fhades from brown to a
deep black are obtained by the ufe of madder j and
by a combination of alum and iron, the colours pro¬
duced are of a mixed nature, inclining on the one
hand to red, and to black on the other. And if ano¬
ther fubftance, as dyers-weed, be fubllituted for the
madder, other colours are obtained. Indeed the great
variety of lhades which are communicated to printed
Huffs are derived from the colouring-matter of madder,
dyers-weed, and indigo, fixed by alumina or the oxide
of iron as mordants.
75. The different fubfiances which enter into the
compofition of a mordant remain in combination till a
new action is induced by the application of another
fubftance. Thus, the affinity of the fluff for one of
their confiituent parts produces a decompofition and
new combinations. But even this effe6l is fometimcs
incomplete, or does not at all take place without the
a£!ion of another affinity, namely, that of the colour¬
ing-particles. We have an example of this in the
mixture of alum and tartar, which is one of the moft
common mordants in the dyeing of wool.
76. The following experiments were made by Ber-
thollet, to afcertain the effefls of thefe fubftances as
mordants. He diffolved equal weights of alum and
of tartar ; and he found that the folubility of the tar¬
tar was increafed by the mixture. By evaporation
and a fecond cryftallization, the two falts were fepa-
rated, fo that no decompofition had taken place. Half
an ounce of alum and one ounce of wool were boiled
together for an hour, a precipitate was formed, which
being carefully wafhed, was found to confift of fila¬
ments of wool incrufted with earth. 1 o this ful-
phuric acid was added, and the folution being evapo^
rated to drynefs, cryftals of alum were obtained, with
the feparation of fome particles of carbonaceous matter.
The liquid in wdiich the wool had been boiled being
evaporated, yielded only a few grains of alum ; what
remained would not cryftallize. This being rediffol-
ved and precipitated by means of an alkali, the alumi¬
na which was thrown down was of a date colour, be¬
came black when placed on red-hot coals, and emitted
alkaline vapours. In this experiment it appears that
the alum was decompofed by the wool, and part of
the alumina had combined with its moft detached fila¬
ments which were leaft retained by the force of aggre¬
gation ) that part of its animal iubitance had been dif-
I N G. ' Part T.
folved and precipitated by the alkali from the triple Of Mor-
. r r dants.
compound. . .
77. The fame experiment was repeated with half
an ounce of alum and two drams of tartar j but no
precipitation followed. A fmall portion of the tartar,
and fome irregular cryftals of alum were obtained by
cryftallization : the remainder refufed to cryftallize j
but being diluted with water, precipitated by potafh,
and evaporated, it yielded a fait which burned like tar¬
tar. The wool which was boiled with the alum had
a harfh feel ; but the other retained all its foftnefs.
The firft, after being fubje&ed to the procefs of mad¬
dening, had a duller and lighter tint; but the colour of
the latter was fuller and brighter.
78. In the firft of thefe experiments the wool had
effefted a decompofition of. the alum, had united with
part of the alumina ; and even part of the alum which
retained its alumina had diffolved fome portion of the
animal matter. In the fecond experiment it appears,
that the tartar and alum, between which there feems to
exift a balance of affinities, can only a£l on each other
by the intermediate action of the wool. The principal
ufe of the tartar feems to be to moderate the adftion
of the alum on the w ool, by wdiich it is injured. In
the aluming of filk and thread, whofe afiion on alum is
lefs powerful than that of wrool, tartar is not found re-
quifite.
79. Whatever be the mode adopted in aluming, or
whatever be the chemical changes which are produced,
its final effedt is the union of the alumina with the
fluff. At firft this combination has probably been in¬
complete, and a partial feparation only of the acids
has taken place ; but it is perfedled after the cloth has
been boiled with the madder, as appeared in the cafe
of printed fluffs *. * ^ °f
8oi The principal fubftances which are employed
for the purpofes of mordants in the proceffes of dyeing,
are earths, metallic oxides, and fome aftringent mat-ufed as
ters. Alumina, which is now one of the moft import-mordants,
ant, and in moft general ufe, was very early employed
as a mordant. This earth, as has been proved by di-
redl experiment, and which is ftill farther confirmed
by daily pradlice and obfervation, is ufeful in the art
of dyeing, in confequence of the affinity which exifts
between it, the fluffs to be dyed, and the colouring
matter. The affinity of alumina for animal matters,
as wrool and filk, is much ftronger than that for vege¬
table produflions, as cotton and linen ; and hence the
difference in the facility of fixing the colours on thefe
different fubftances, and in their durability.
81. When alumina is employed as a mordant, it is al- Alum,
ways in a ftate of combination, either in that of alum,
which is the fulphate of alumina and potafh, or united
with the acetous acid, forming the acetate of alumina.
Alum was employed at a very early period as a mor¬
dant. It was ufed by the ancients as it was found na¬
tive, and therefore far from being in a ftate of purity.
But as the nature of the conftituent parts of alum
was long unknown, its ufe in dyeing, as well as that
of mordants in general, can only be ranked among the
difcoveries of modern chemiftry. Alumina is alfo em¬
ployed for a fimilar purpofe, in combination with the
acetous acid. T'his combination of alumina feems to
have been firft introduced about the beginning of the
18th century, and its introduftion, like other valuable
improvements,
Chap.
Of Mor¬
dants.
Lime.
Metallic
«xkles.
I. . D Y E
improvements, was owing to accident. It was firft em¬
ployed by the callico-printers; but at what time, or
by whom it was firft ufed, is not exaftly known. In
one of the earlieft recipes for preparing the mixtures
employed as mordants in callico-prmting, which Dr
Bancroft, in his inveftigation of this fubjeft, informs us
he examined, the fubftances directed to be ufed are
alum, fal ammoniac, fait petre, red orpiment, and
kelp ; and thefe were to be mixed with water. In
another, which he obferves probably followed this,
thefe ingredients were to be diffblved in vinegar.
Sugar-of-lead was afterwards added in fmall quantity,
and among a great variety of other fubftances which
were employed at different times, litharge and white-
lead came into ufe. In cafes where vinegar was em¬
ployed as the folvent, after different decompofitions
had taken place, a portion of acetate of alumina was
formed, and the ufe of it was found to be followed
with good effeas. The quantity of lugar-oi-lead, trom
obferving the advantages derived from it, was gradual¬
ly increafed, and the employment of many of tne
other fubftances which were found by experience to
be ufelefs, was omitted. As the introduftion of acetate
of alumina was at firft owing to chance, and as; the
changes and decompofitions which took place in its
formation were entirely unknown, it is not to be
wondered at that the difeovery or invention of this
fubftance as a mordant, ftiould not be diftinflly aicer-
tained. . ~
8z. The ufual method of preparing the acetate ot
alumina is by pouring acetate of lead into a folution of
alum. Both the falts are decompofed, by an exchange
of their conftituent parts. _ The fulphuric acid and the
l ad having a ftronger affinity than the fulphuric acid and
the alumina, combine together, and fall to the bottom
in the form of an infoluble powder. The alumina at
the fame time enters into combination with the acetous
acid, and remains diffolved in the liquid. But the
application and effefts of this fubftance in dyeing have
been fully illuftrated in treating of mordants in gene-
ral. . ...
83. Lime is the only earth, befides alumina, which
is employed in dyeing. The affinity of lime for cloth
is fufficiently ftrong 5 it is, however, found to anfwer
the purpofe of a mordant lefs perfeftly than alumina,
on account of the colour, which is not fo good. It is
employed, either in the ftate of lime water, or in tnat
of fulphate of lime difiblved in water.
84. Metallic oxides have a ftrong affinity for animal
fubftances. They have alfo fo great an attraftion for
many colouring matters, that they feparate fiom the
acids with which they are combined, and are precipi¬
tated in combination with the colouring matters. . In
confequence of thefe different affinities, metallic oxides
'are of great importance in dyeing, and hence they
were early applied in that art, and are now extenfive-
ly ufed. ’ But befides the affinity of thefe oxides for
the colouring particles, and for animal fubftances, their
folutions in acids poffefs properties by which they are
more or lefs fit to be employed as mordants. "I hus,
thofe oxides which eafily part with their acids, Inch as
that of tin, are capable of entering into combination
with animal fubftances, without the aid of colouring
particles. All that is neceffary is to impregnate the
wool or the filk with a folution of tin. Some metallic
I N G.
405
fubftances yield only in combination a white and co- OfMor-
lourlefs balls; but there are others which, by means ot —
their own colour, produce modifications on the peculiar
colour of the colouring particles. But the effects ot
many metallic oxides are extremely different, accord¬
ing to the proportion of oxygen with which they are
combined •, and this proportion is variable.
85. The affinity of metallic oxides for vegetable
matters is confiderably weaker than that which they
have for animal fubftances. Metallic folutions, there¬
fore, are found not to anfwer fo well as mordants tor
colours in dyeing cotton or linen. Iron, indeed, is an
exception, the oxide of which, it is well known, has a
ftrong affinity for vegetable fubftances. . Iron moulds
on cotton or linen are owing to a combination 01 the
oxide of iron with the vegetable matter.
86. Although almoft all metallic oxides have an
affinity for animal and vegetable matters, and might
therefore be employed as mordants, yet two only,
either becaufe they are found to anfwer the purpolc
better, or becaufe they are cheaper, are ufed to any
extent. Thefe are the oxides of tin and of iron.
87. The ufe of the oxide of tin feems to have been Oxide ot
firft difeovered by a German chemift of the name of tin.
Kufter or Kuffler. Obferving the effea^s of a folution
of tin in nitric acid, in giving a more vivid colour to
fluffs dyed with cochineal, he w'as led to the difcoveiy
of the method of producing wftiat has fince been deno¬
minated cochineal fcarlet. 'Ibis difeovery has been
aferibed by others to Drebel, a Dutch cnemift . and
Macquer, who is of this opinion, fuppofes that the firft
folutions of tin were made withnitro-muriatic acid", but
Dr Bancroft thinks that there is good reafon to be¬
lieve, that nitric acid only w!as ufed for fome years for
this purpofe. According to Mr Delaval, the ufe of tin
in dyeing was known to the ancients *, and he fuppofes
that the tin which the Phoenicians carried from Bri¬
tain, was employed in this way, becaufe he thinks that
it is neceffary to the produftion of red colours, whe¬
ther from animal or vegetable matter. .Dr Bancroft,
however, has proved, that this opinion is founded in
miftake.
88. About the year 1543, Kufter brought his fecret
to London, and it appears that it was firft employed
for this purpofe at Bow. Hence the .fcarlet colour
thus produced was denominated in this country the
Bow dye. It feems too, that this mode of dyeing fcar¬
let was very early introduced into Holland. A
Frenchman of the name of Gobelins, received an ac¬
count of the pvocefs from a Flemifh painter called
Kloeck, to whom it had been communicated by Kuf¬
ter himfelf, and eftablilbed it in France. Hence the
Bow dve of England was known in other parts of Eu¬
rope under the names of Dutch fcarlet, fcarlet of the
jobelins. a a. c
89. We have mentioned above, that the effects ot
metallic oxides as mordants in dyeing, depend on the
different proportions of oxygen with which they may
be combined. Thus, there are two oxides of tin con¬
taining different proportions of oxygen ; tiie one con¬
tains 30 parts of oxygen in the too, and the other con¬
tains 40. The oxide having the fmaller proportion of
oxygen, by being expofed to the air combines with a new
portion of oxygen, and is foon converted into, the oxide
with the greater proportion, or the white oxide. It is
this
406
Of Mor-
dants.
Prepara¬
tion.
DYE
this Jaft which is the mordant, for if the other were ap-
j plied to the ftuiF, it would foon be converted into the
white oxide, by combining with an additional portion
of oxygen.
90. t in was firft ufed as a mordant diffolved in ni¬
tric acid j but this preparation was found not to an-
fwer wTell, becaufe the nitric acid readily converted the
tin to the ftate of white oxide, in w’hich ftate it is in¬
capable of diffolving it. A precipitation of the tin
took place, to prevent which, different fubftances were
added, as common fait, or fal ammoniac ; and thus a
nitro-muriatic acid was produced, by which means the
white oxide of tin was held in folution. It appears,
however, that it wras a confiderable time before this
method came into general ufe. Hellot, in an account
of the procefs employed in his time for dyeing fcarlet
at Carcaflbnne, mentions that the tin was difiblved
only in diluted nitric acid, adding that a Mr Baron
W'as the firft in that city who employed nitro-muriatic
acid for the folution of tin, to prevent the precipitation
of the oxide.
91. The ordinary folution of tin is made with that
fpecies of nitric acid called Angle aquafortis, and as it
is ufually prepared, it is found capable of difiblving a-
bout £ part of its weight of granulated tin. To each
pound of aquafortis from one to two ounces of fea fait,
or, w hat is deemed preferable by fome, of fal ammoniac,
are added. The acid is commonly diluted with a little
water. The folutions which are made moft flowly,
and with the leaft leparation of vapours, are found to
fucceed beft. Two ounces of granulated tin are ufu¬
ally allowed for each pound of aquafortis j and the
metal (hould be added at different times, to moderate
the rapidity of the folution. The water added to
the acid {hould be weighed or meafured, that a folu¬
tion of the fame ftrength may be always obtain¬
ed. Eighteen or 20 pounds of this folution (a) are
required to give a full cochineal fcarlet to 100 pounds
of woollen cloth.
92. But in the dyeing of fcarlet, according to the
ordinary procefs, a quantity of tartar is diflblved in the
water, along with the nitromuriate of tin ; and if the
tartar be employed in fufficient quantity, the mordant
is not to be confidered ^as a nitromuriate of tin, but a
tartrate or combination of tin with tartaric acid, in
confequence of the decoinpofition which takes place,
when thefe fubftances are brought to aft on each other;
for the nitromuriatic acid enters into combination with
the potaftr or the tartar, while the acid of the tartar forms
a compound with the oxide of tin.
93. It has been propofed by Haufi'man to employ the
acetate of tin as a mordant for cotton and linen, in-
llead of the nitromuriate. The acetate of tin is pre¬
pared by mixing together acetate of lead and nitro¬
muriate of tin; andasthe affinity between metallic oxides
and vegetable fubftances is lefs powerful than the affi¬
nity between thefe oxides and animal matters, this mor¬
dant has been found preferable for cotton and linen
{luffs; for the affinity of the oxide of tin for the acetous
acid being weaker than for the nitromuriatic acid, it is
more eafily decompofed.
I N G. Part I.
94. Dr Bancroft * tried the folution of tin in fulphu- 0f M°r-
ric acid, but found that it would not anfwer, on ac-, dants.
count of its deftrudlive aft ion on the cochineal colour;*/^/;
but he found afterwards, that, by the ufe of muriatic0/Weil,
acid combined wdth ^ its weight of fulphuric acid, Co/. 28$.
good effefts wrere obtained. The proportions which
he employed were about 14 ounces of tin in a mix¬
ture of 2 pounds of fulphuric acid of the ordinary
ftrength, with about 3 pounds of muriatic acid. This
preparation may be made in the cold ; but the folu¬
tion is very rapidly promoted with a fand heat. The
folution of tin made in thefe proportions, Dr Bancroft
obferves, is perfeftly tranfparent and colourlefs ; and in
the fpace of three years, during which time he kept a
folution of it, no precipitation had taken place. It pro¬
duces, he adds, full twice as much effeft as the dyer’s
fpirii, or nitromuriatic folution of tin, and at lefs than
one-third of the expence.
95. Iron exifts in two ftates of combination with Oxide of
oxygen. In the ftate of green oxide it contains theIron-
fmaller proportion of oxygen, and in that of red oxide
the greater proportion. In the laft ftate it can only
be employed as a mordant in dyeing; for if it be ap¬
plied in the ftate of green oxide, in confequence of its
ftrong affinity for oxygen, it attrafts it from the atmo-
fphere, and is foon converted into red oxide. The dif¬
ficulty of removing iron fpots or mould from cotton
or linen fliows with what force of affinity the red oxide
of iron adheres to cloth. Iron is employed as a mor¬
dant in two ftates of combination, either in that of ful-
phate or acetate of iron. The fulphate of iron is ge-.
nerally employed for wool. The fluff is immerfed in
the folution of the fait in water. In this ftate it may
be alfo ufed for cotton ; but it is more commonly pre¬
ferred in the ftate of acetate of iron. This is the com¬
bination of iron with the acetous acid, and it is ufually
prepared by diffolving iron in vinegar or four beer;
and the longer it is retained in the folution, it is
found to aft more powerfully as a mordant, becaufe it
is then in a ftate of more complete oxidation.
96. Some other faline bodies are alfo employed
as mordants, to facilitate the combination of the co¬
louring matter with the cloth, or to produce greater
variety of (hades of colour. Among thefe fubftances
may be mentioned common fait, fal ammoniac, ace¬
tate of lead, fulphate and acetate of copper, fulphate of
zinc.
97. Befides the mordants obtained from the clafs of Animal
falls, vegetable and animal fubftances alfo ferve a fimilarand vege-
purpofe. In the procefs for dyeing the Turkey red, ta^e mat"
which will be afterwards deferibed, the cotton fluffsterS’
{hould be impregnated with an animal fubftance, as oil;
and the aftringent principle is often employed as a me¬
dium of combination between colouring particles and
fluffs. Tan, or the aftringent principle, having a ftrong
affinity for cloth, is found extremely ufeful as a mor¬
dant. It is commonly prepared by infufing nut-galls
in water. The cloth is immerfed in this folution, and
allowed to remain till it is fufficiently impregnated
with the tan. Sumach, which is the (hoots of the Rhiu
coriaria Lin. a (hrub, which grow’s in the fouthern parts
of
  —  ■   
(a) This folution is called jfnrit by the dyers in this country.
Chap. I!L DYE
Of Mor- of Europe, is often ufed and prepared in the fame way
dants. as j.j.jg nut.galls.
Effeft 0f 9^- Mordants have a very cdnfiderable eflFeft on the
mordants colour ; and, by varying the mordant, very different
on the co- colours, and a great variety of (hades, may be obtained
lour. from the fame colouring matter. Some mordants
themfelves may be confidered as communicating a co¬
lour without the addition of any colouring fubftance $
and although, when the latter is added, a new fet of
of affinities is brought into aftion, yet there is little
doubt that the mordant alfo has a confiderable ffiare in
fixing the (hades of colour. Let us take an example
in dyeing with cochineal. When the aluminous mor¬
dant is employed, the colour produced is crimlon 5 but
when the oxide of iron is fubftituted for the alumina,
the colour obtained is black. This effefts is obviouf-
ly produced by a change in the aftion of the affinities
between the colouring matter and the mordant, and
the colouring matter and light. In the ufe of mor¬
dants, therefore, it is neceffary to attend to their com¬
bined effedts with the colouring matter employed, and
to be able to communicate particular colours to fluffs
with any degree of certainty, to know the amount of
that effedt.
99. Even in the mode of applying mordants, the
variety of (hades may be greatly multiplied. Different
effedts, for inftance, are produced by previoufiy im¬
pregnating the fluff with the mordant, or by mixing it
with the bath. Different effedls alfo arife from ufing
heat, or, as the fluff is more or lefs rapidly dried j and
this mud appear to be the cafe, if we confider the dif¬
ferent affinities which are in adlion, and the change on
the adlion of thefe affinities in thefe different circum-
flances, as well as in others which can fcarcely be ap¬
preciated. The combination of thefe fubflances which
have an affinity for the fluff, and the decompofitions
which are the refult of that combination, are greatly
facilitated by the evaporation of the water or other li¬
quid which held thefe fubflances in folution j becaufe
by its affinity, which is oppofed to the adlion of the affi¬
nity between thefe fubllances and the fluff, the affinity
of the latter produces a more limited effedl. But in
dyeing, the procefs fhould proceed (lowly, that the fub-
ftances may not be feparated before their mutual afhni-
nities have begun to operate.
100. Confiderable differences muff be obferved in the
mode of employing the mordant, as the force of affinity
between the fluff and the colouring matter is greater
or lefs. When this affinity is flrong, the mordant and
the colouring fubflance may be mixed together $ the
compound thus formed, immediately enters into combi¬
nation with the fluff. But if the affinity between the
fluff and the colouring particles be weak, the compound
formed of the latter and the mordant may feparate,
and a precipitation take place, before it can be attach¬
ed to the fluff; and hence it is in thefe cafes, that the
mordant which is to ferve as the medium of union be¬
tween the fluff and the colouring matter, muff be
combined with the former, before the application of
the latter. It is from thefe differences that different
procefies muff be followed in fixing colouring mat¬
ters on animal and vegetable produftions ; as for
inftance, in dyeing wool or (ilk black, or with co¬
chineal.
I N G. 407
101. In eftimating the effe£fs of mordants, and in Of Sub¬
judging of the moft advantageous manner of applying ftancest»-
them, it is neceffary to attend to the combinations which 11'
may be formed, either by the a£lion of the ingredients v.-J
of which they are compofed, or, by that of the colour¬
ing matter and the fluff. It is neceffary alfo, to take
into confideration the circumftances which may tend to
bring about thele combinations with more or lefs rapi¬
dity, or that may render them more or lefs perft£h
The aftion which the liquor in which the fluff is im-
merfed may have, either on its colour or texture, muft
alfo be confidered j and to be able accurately to judge
of the extent of this aftion, wTe muft know? the propor¬
tions of the principles of which the mordant is com¬
pofed j w’hich of thefe principles remains in an URCom-
bined ftate in the liquor, and the proportion or quanti¬
ty which is thus feparated.
Chap. III. O/' the Nature and Properties of the Sub-
fauces to ’which Colours are communicated in the
Procejfes oj Dyeing.
102. In the more limited fenfe to which we have here
reftridled the art of dyeing, the fubftances to which
colours are ufually communicated by means of this
art, are wool, filk, cotton, flax, and hemp. Of thefe,
the two firft are animal fubflances, and the three lat¬
ter are derived from the vegetable kingdom. Thefe
two claffes of bodies prefent ftriking differences, not
only in ftru&ure, but alfo in their compofition and
chemical properties.
103. Animal fubftances are diftinguiffied from thofe Difference
which have a vegetable origin, by the nature of their between
conflituent parts. The former contain a large proportion an*ma' an<^
of azote, w hich exifts fparingly in the latter. Hydrogen,
or the bafe of hydrogen gas or inflammable air, is
found in greater abundance in animal matters, than in
vegetable produdlions. In the diftillation of animal
and vegetable fubflances, the difference of their con¬
flituent parts is not lefs remarkable. The former af¬
ford a large proportion of ammonia, or volatile alkali ;
the latter yield very little, and fometimes give out an
acid fubftance. Animal matters afford much oil, while
vegetable fubftances fometimes do nof-afford it in any
perceptible quantity. From the nature of their com¬
ponent parts, animal fubftances produce a bright flame in
burning ; and their combuftion is accompanied with a .
penetrating odour, which is owing to the formation and
emiffion of ammonia and oil. Animal matters run
rapidly into the putrefa£live procefs, while vegetable
fubftances more flowly undergo the changes which are
induced by the vinous or acetous fermentation.
104. The conftituent principles of animal fubftances
have a ftronger tendency than thofe which enter into the
compofition of vegetable matters, to a flume the elaftic
form. On this account the cohefive force exifting be¬
tween the particles of the former is inferior to that of
the particles of the latter. Hence animal matters are
more difpofed to combine with other fubftances, more
liable to be deftroyed by different agents, and to en¬
ter into combination with colouring particles. Thusp ,
animal fubftances are deftroyed by the cauftic fixed al¬
kalies, and they are decompofed by the nitric and ful-1-
pburicc
3 ■
408
Of Sub-
ftances to
' be colour¬
ed.
DYE
phuric acids. The aftion of acids and alkalies on filk
is lefs powerful than upon wrool, and it is lefs difpofed
to combine with the particles of colouring matter. In
this refpeft it bears fome refemblance to vegetable fub-
ftances j but on vegetable matters, the a6lion of alka¬
lies and acids is lefs powerful than on animal fub-
ftances j and the aftion of acids is more feeble on
cotton than on flax or hemp. It is even decompo-
fed with confiderable difficulty by means of nitric
acid.
In the four following fe&ions, we fhall confider
the peculiarities of thefe fubflances at greater length.
Sect. I. Of Wool.
Strudure. Wool, which is well known as the covering of
ffieep, derives its value from the length and finenefs of
its filaments. The filaments of wool are confiderably
elaftic, for they may be drawn out beyond their ufual
length, and when the force is removed, they recover
it again. The furface of the filaments of wool or hair
is not perfeftly fmooth for although no roughnefs or
inequality can be difcovered by the microfcope, yet
they feem to be formed of fmall laminae placed over
each other, in a flanting diredlion, from the root of the
filament towards its point, refembling the arrangement
of the fcales of a fiffi, which cover each other from the
head of the animal to its tail •, or perhaps they confift
of zones placed over each other, as is cbferved in the
horns of animals. This peculiarity of ftru&ure of the
filaments of hair and wool is proved by a Ample expe¬
riment. If a hair be laid hold of by the root in one
hand, and drawn between the fingers of the other hand,
from the root towards the point, fcarcely any fri&ion
or refiftance is perceived, and no noife is heard ; but
if it be grafped by the point, and paffed in the fame
manner between the fingers from the point towards the
root, a refiftance is felt, and a tremulous motion is
perceptible to the touch, while the ear is fenfible to a
flight noife. Thus it appears, that the texture of the
furface of hair or wool is not the fame from the root
towards the point, as it is from the point towards the
root. This is farther confirmed by another experi¬
ment. If a hair be held between the thumb and fore¬
finger, and they are rubbed againrt each other in the
longitudinaldire&ionofthehair, it acquires a progreffive
motion towards the root. This effefl depends not on
the nature of the fkin of the finger, or on its texture,
for if the hair be turned, and the point placed where
the root formerly was, the motion is reverfed, that is,
it will Hill be towards the root.
. 106. On this peculiarity of ftru&ure, which was obfer-
eUin£- vej by Monge, depend the proceffes of felting and
fulling, to which hair and wool are fubje&ed, for differ¬
ent purpofes. In the procefs of felting the flocculi of
wool are ftruck with the firing of the bow, by which
the filaments are feparately detached, and difperfed in
the air. Thefe filaments fall back on each other in* all
directions on the table, and when a layer of a certain
thicknefs is formed, they are covered with a cloth, on
which the workman preffes with his hands in all parts.
Ey this preffure the filaments of wool are brought
rearer to each other; the points of contact are multi¬
plied ; the progreffive motion towards the root is pro-
I N G. Parti.
duced by the agitation; the filaments entangle each Of Sub-
other ; and the laminae of each filament, taking hold of
thofe of the other filaments, which are in an oppofite ecl
direClion, the whole is retained in the ftate of clofe t—y—j
contexture.
107. ConneCted with this operation is that of fulling. Fulling.
The roughnefs on the furface of the filaments of wool,
and their tendency to acquire a progreflive motion to¬
wards the root, produce confiderable inconvenience in
the operations of fpinning and weaving. Thefe'incon-
veniences are obviated by covering the filaments with
a coat of oil, which fills up the cavities, and renders
the afperities lefs fenfible. When thefe operations are
finilhed, the fluff mult be freed from the oil, which
would prevent it from taking the colour with which it
is to be dyed. For this purpofe it is taken to the ful¬
ling-mill, where it is beaten with large beetles, in a
trough of water, through which clay has been diffufed.
The clay unites with the oil, which being thus ren¬
dered foluble in the wrater, is carried off by freffi por¬
tions of water, conveyed to it by proper apparatus.
In this way the fluff is fcoured ; but this is not the foie
objeCt of the operation. By the alternate prtffure of
the beetles, an effeCt fimilar to that of the hands in the
operation of felting, is produced. The filaments com-
pofing a thread of warp or woof, acquire a progreflive
motion, are entangled with the filaments of the ad¬
joining threads ; thofe of the latter into the next, and
fo on, till the whole threads are felted together. The
fluff is now contracted in all its dimenfions, and parti¬
cipating both of the nature of cloth and of felt, may
be cut without being fubjeCled to ravel ; and when
employed to make a garment, requires no hemming.
In a common woollen flocking web, after this opera¬
tion, the flitches, when one happens to flip, are now
no longer fubjeCt to run, and the threads of the warp
and woof being lefs diftinCt from each other, the
whole fluff is thickened, and forms a warmer cloth-
ing.
108. The various manufactures, of w hich wool con-importance]
ftitutes the bafis, are juftly regarded among the moft im- of vrool.
portant to man in civilized fociety. Accordingly, the
production of fine w'ool, and the caufes which retard
or improve the breed of fheep from which it is obtain¬
ed, have greatly occupied the attention of economifls
and philofophers in our own, as w'ell as in other coun¬
tries. The wool of different breeds of ffieep, in differ¬
ent countries, it is well known, poffeffes very different
qualities, both with regard to the finenefs of the fila¬
ment, and the colour. Some is of a wffiite, or yellow,
and fome of a reddifli, and black colour. Excepting
the wrool of the breed of flieep in Andalufia, the Spa-
niffi wool was formerly all of a brownilh black colour.
This was preferred by the native Spaniards; and even
at this day, the drefs of fome religious orders in Roman
Catholic countries, confifts of cloth manufactured from
this wool, and retaining its natural colour. But for
the purpofes of dyeing, white wool is now’ always pre¬
ferred, becaufe it is found fufceptible of receiving bet¬
ter and more durable colours.
109. Wool is naturally covered with a kind of greafe Scouring
or oil, which is found to preferve it from infeCls or moths,
and on this account this greafy matter is not removed,
or the wool is not fcoured till it is to be dyed
* •- o?
Chap. II f.
DYE
Of Sab- or fpun (a). The procefs for fcouring wool is the fol-
ftances to lowing. It is put for about a quarter of an hour into a
be colour. kett}(r with a fufficient quantity of water, to which a
. ^ i fourth part of putrid urine has been added. It is then
heated to fuch a degree as the hand can beaij occa-
fionally ftirred, and after being taken out, is allowed
to drain. It is then put into a bafket, and cxpofed to
a ilreatn of running water, and moved aoout till the
greafe is fo completely feparated, that it no longer ren¬
ders the water turbid. After being drained, it is fome-
times found to lofe by this operation above one-fifth of
its weight. It is almod unneceflary to oblerve, that
the’more carefully and completely tnis proceis is per¬
formed, the better the wool is fitted to receive the co¬
louring matter. Our chemical readers will readily
perceive the nature of the changes which are effeded in
this procefs of fcouring. The ammonia, or volatile al¬
kali, which exids in the urine, combines with the oil
of the wmol, and forms a foap, which being foluble in
water, is diffolved, and carried off.
Dyeing. ! i0> Wool is either dyed in the deece, or after it is
fpun into threads, or when it has been manufactured into
cloth. For the purpofe of forming cloths of mixed
colours, it is dyed before it is fpun ^ for the purpofes
of tapedry, it is dyed in the date of thread •, but mod
commonly it is" fubje&ed to this procefs after it has
been manufactured into cloth. In thefe different dates,
the quantity of colouring matter which is taken up is
very different. The proportion is larged w-hen it is
dyed in the deece, becaufe then the filaments being
more feparated, a greater furface is expofed to the ac¬
tion of the colouring particles. For a fimilar realon
the quantity of colouring matter taken up is greater
when in the date of thread or yarn, than when it is
formed into cloth. But cloths themfelves mud vary
greatly in this refpeCl, according to their different
qualities. Their different degrees of finenefs, or clofe-
nefs of texture, will produce confiderable variations ;
and befides, the difference in the quantity and dimen-
fions of the fubdances to be dyed, the different quali¬
ties of the ingredients employed in the procefs, and
the different circumdances in which it is performed,
fhould be a caution againd truding to precife quanti¬
ties, regulated by weight or meafure, which are re¬
commended according to general rules. According
to the finenefs of the texture of the wool, and the na¬
ture of the colouring matter employed, it is found to
be more or lefs -penetrated with this matter. The
co^rfe wool from the thighs and tails of fome fheep,
receives colours with difficulty, and the fined cloth is
never completely penetrated with the fcarlet dye. The
interior of the cloth appears always when cut, of a
lighter fhade, and foinetimes even white.
Sect. II. OfSM.
Origin. III. Silk, which forms the bafis of one of the riched
and mod fplendid parts of drefs, among the wealthy
and luxurious, in civilized fociety, is the produ&ion
of different fpecies ofinfedls. The phalctna bombyx, or
filk-worm, which is a native of China, attracted the
Vol. VII. Part II.
I N G. , t 409
attention of mankind in that country, from the earlieft
ages. The honour of having fird colledled and pre- ^eacoiour_
pared filk from the cocoons or balls in which it is e(k
wound up by the infeft, during its metamorphofis, is \ »
afcribed by the Chinefe hidorians, to the wife of an
emperor. The phalcetici atias^ Lin. which is alio a na¬
tive of China, is faid to form larger cocoons, and to
yield a dronger filk. The dlk-worm was fird carried
from China to Hindodan, and afterwards to Perda.
Silk feems not to have been known to the Greeks or
Romans till the time of Augudus. Its nature and ori¬
gin were little underdood, and for many ages it vyas
fo fcarce, that it could only be purchafed at a price
which was equal to its weight in gold. T he emperor
Aurelian, it is faid, from a principle of economy, re-
fided the urgent folicitations of his emprefs, who wifh-
ed to have a filken robe, alleging the extravagance of
the expence. About the middle of the fixth century,
two monks returned from India to Condantinople, and
brought with them a confiderable number of filk-
worms, with indrudlions for managing and breeding
them, as well as for collefting, preparing, and manu¬
facturing the filk. Eftablidiments were thus formed
at Corinth, Athens, and other parts of Greece. The
crufades, which greatly contributed to the diffufion of
different kinds of knowledge, by the intercourfe which
took place between different countries, proved ufeful
in diffeminating the knowledge of rearing the fiik-
worm, and preparing and rdanufaCturing its valuable
productions. Roger, king of Sicily, about the year
1130, returning from one of thefe frantic expeditions,
brought with him from Athens and Corinth, feveral
piifoners, who were acquainted with the management
of filk-worms, and the manufacturing of filk. Under
their fupeiintendance, manufactories were edablidied
at Palermo and Calabria in Sicily. I his example was
foon adopted, and followed in different parts of Italy
and Spain. In the time of James I. an attempt was
made to edablidi the filk-worm in England. For this
purpofe the culture of the mulberry-tree on which the
infeCts feed, was drongly recommended by that prince
to his fubjeCts j but the attempts which were made
have been hitherto unfucceisful.
112. The fibres of filk are covered w ith a coating or Scouring,
natural’varnidi of a gummy nature. To this are afcrib¬
ed its diffnefs and eladicity. Befides this varnidi, the
filk which is ufually met rvith in Europe is impregna¬
ted with a fubftance of a yellow colour, and for mod
of the purpofes to which filk is applied, it is neceffary
that it diould be deprived, both of the varnidi and of
the colouring matter. On this account it mud be lub-
jeCIed to the operation of fcouring 5 but for filks which
are to be dyed, this procefs diould not be carried fo
far as for thofe which are merely to be whitened ; and
different colours, it is obferved, require different de¬
grees of this operation. The quantity of foap condi-
tutes the chief difference. A hundred pounds of filk
boiled in a folutiou of 20 lbs. of foap for three or four
hours, adding new portions of water during the evapo¬
ration, are fufficiently prepared for receiving common
3 F colours.
(a) According to an obfervation of Reaumur, rubbing any duff with greafy wool, is fufficient to preferve it
from moths.
4io
DYE
ployed
white.
Of Sub- colours. For blue colours, the proportion of foap mull
be colour- be Jncreafed and fcarlet, cherry-colour, &c. require
ed. U * a greate1' proportion, for the ground mutt be
1 — v‘..., > wliiter for thefe colours.
Procefs, i i 3. Silk which is to be employed white, mull undergo
three operations. In the firft the hanks are immerfed
in a hot but not boiling folution of 30 lbs. of foap to 100
of filk. When the immerfed part is freed from its
gum, which is known by its whitenefs, the hanks are
lhaken over, as the workmen term it, fo that the part
which was not previoully immerftd may undergo the
lame operation. They are then wrung out as the pro¬
cefs is completed. In the fecond operation the filk is
put into bags of coarfe cloth, each bag containing 20
or 30 lbs. Thefe bags are boiled for an hour and a
half, in a folution of foap prepared as before, but with
a fmaller proportion of foap ; and that they may not
receive too much heat, by touching the bottom of the
kettle, they muft be conllantly {lined during the ope¬
ration. The object of the third operation is to com¬
municate to the filk different {hades, to render the
white more agreeable. Thefe are known by different
names, as China-white, filver-white, azure-white, or
thread-white. For this purpofe a lolution of foap is
alfo prepared, of which the proper degree of ftrength
is afeertained by its manner of frothing by agitation.
For the China-white, which is required to have a flight
tinge of red, a fmall quantity of anatto is added, and
the fiik is fhaken over in it till it has acquired the
fhade which is wanted. In other whites, a blue tinge
is given by adding a little blue to the folution of foap.
The azure-white is communicated by means of indigo.
To prepare the azure, fine indigo is well wafhed two or
three times in moderately warm water, ground fine in a
mortar, and boiling water poured upon it. It is then
left to fettle, and the liquid part only, which contains
the finer and more foluble parts, is employed.
114. Someufeno foapin the third operation 5 butwhen
the fecond is completed, they wafh the filks, fumigate
with fulphur, and azure them with river water, which
fliould be very pure. But all thefe operations are not
fufficient to give filk that degree of brightnefs which
is neceffary, when it is to be employed in the manu-
fafture of white fluffs. For this purpofe it muft un¬
dergo the procefs of fulphuration, in which the filk is
expofed to the vapour of fulphur, for an account of
which fee Bleaching. But before the filk which has
been treated in this way is fit for receiving colours,
and retaining them in their full luftre, the fulphur
which adheres to it muft be feparated by immerfion and
agitation for fome time in warm water, ctherwife the
colours are tarnifhed and greatly injured.
115. It has long been an object of confiderable import¬
ance, to deprive filk of its colouring matter, without
deftroying the gum, on which its ftiffhefs and elafticity
depend. A procefs for this purpofe was difeovered by
Beaume, but as it was not made public, others have
been led to it by conjedlure and experiment. The
followung account, given by Berthollet, is all that has
tranfpired concerning this procefs. A mixture is made
with a fmall quantity of muriatic acid and alcohol.
The muriatic acid fhould be in a ftate of purity, and
particularly fhould be entirely free from nitric acid,
which would give the .filk a yellow colour. In the
mixture thus prepared, the filk is to be immerfed.
Mode of ex-
trailing its
colouring
matter.
1 n g. part r.
One of the moft difficult parts of the procefs, efpecial- Of Sub,
ly when large quantities are operated upon, is to pro- ltances to
duce a uniform whitenefs. In dyeing the whitened be <^lour''
filk, there is alfo confiderable difficulty, to prevent its , * ,
curling, fo that it is recommended to keep it conftant-
ly ftretched during the drying. The muriatic acid
feems to be ufeful in this procefs, by foftening the
gum, and affifting the alcohol to diffolve the colouring
particles which are combined with it. The alcohol
which has been impregnated with the colouring mat¬
ter may be again feparated from it and purified, that
it may lerve for future operations, and thus render the
procefs more economical. This may be done by
means of diftillation with a moderate heat, in glafs or
llone-ware vefiels.
1 16. The preparation with alum is a very important Aluming,
preliminary operation in the dyeing of filk. Without
this procels, few colours would have either beauty or
durability. Forty or fifty pounds of alum, previoufly
diftblvcd in warm water, are mixed in a vat, with
forty or fifty pailfuls of w'ater ; and to prevent the cry-
llallization of the fait, the folution muft be carefully
ftirred during the mixture. The filk being previoufty
wafhed and beetled, to feparate any remains of foap,
is immerfed in this alum liquor, and at the end ef
eight or nine hours is wrung out, and wafhed in a
ftream of water. A hundred and fifty pounds of fiik
may be prepared in the above quantity of liquor ; but
when it begins to grow weak, which may be known
by the taffe, 20 or 25 lbs. of difiblved alum are to be
added, and the addition repeated till the liquor acquires
a difagreeable fmell. It may then be employed in the
preparation of filk intended for darker colours, till its
whole ftrength is diffipated. This preparation of filk
with alum muft be made in the cold ; for when the
liquor is employed hot, the luftre is apt to be im¬
paired.
Sect. III. Q/'Cotton.
I ty. Cotton is the down or wool contained in the origin,
pods of a fhrubby plant, which is a native of warm cli¬
mates. Of this genus of plants (GoJJypmm Lin.) there
are four fpecies, one of which only is perennial 3 the
other three are annual plants 5 but of thefe there are
many varieties, occafioned by the difference of foil or
temperature in which they are produced. The princi¬
pal differences among cottons confift in the length and
finenefs of the filaments, and in their ftrength and co¬
lour.
118. The peculiar ftru£lure of the fibres of cotton isStrudlure.
not well known. According to the microfcopic obferva-
tions of Leeuwenhoek, they have two (harp fides, to
which are aferibed the irritation and inflammation of
wounds and ulcers, when they are dreffed with cotton
inftead of lint. This peculiarity of ftru6!ure, it is alfo
fuppofed, may occafion fome difference in the confor¬
mation, and number of the pores, on which alone the dif-
pofition of cotton to admit and retain colours better
than linen, feems to depend. In this refpeff, however,
it is inferior to wool and filk, becaufe on account of its
vegetable nature, its affinity for colouring matter is lefs
powerful.
119. It is w^ell knowrn that filk, cotton, and linen have Has a lefs
a weaker affinity for colouring matter than wool. Jje
Pileur d’Apligny attempts to explain this by ftippofingj^^^ co*
that matter.
Chap. III. DYE
0£Sub- that the pores of thefe fubftances are fmaller than thofe
ftances to 0f WOol, and that the colouring particles enter them
be Ce°J0Ur" ea% anc^ ^eely. But according to the obferva-
t ^ ‘ tion of Dr Bancroft, the reverfe of this feems to be the
faft j for there is little difficulty in making filk, cot¬
ton, and linen, imbibe colouring matter, even when it is
applied cold without any artificial dilatation of the
pores, which is always neceffary in the dyeing of wool.
The only real difficulty is to make them retain the
colours after the matter has been imbibed; becaufe
being admitted fo readily into their undilated pores,
the particles cannot be afterwards comprefled and re¬
tained by the contraftion of thefe pores, as is the cafe
with wrool. It requires double the quantity of cochi¬
neal which is neceffary for wool to communicate a crim-
fon colour to filk j a certain proof that it can take up
a greater quantity, and confequently that the pores are
fufficiently large and acceffible. Unbleached cotton
is always preferred for dyeing Turkey red *, becaufe in
this ftate the colour is found to be moft permanent ;
and this is afcribed to the pores or interffices being lefs
open than after it has undergone the procefs of bleach¬
ing. The fame thing is obferved of raw or unfcoured
filk.. It is found to combine more eafily with the co¬
louring matter, and to receive a more permanent co¬
lour in this ftate than after it has been fcoured and
whitened. “ The opennefs of cotton and linen, (fays
Dr Bancroft) and their confequent readinefs to imbibe,
both colouring particles, and the earthy or metallic
bafes employed to fix moft of them, are circumftances
upon which the art of dyeing and callico-printing is in
* Pbilof.of a great degree founded But is not this too me-
Permanent chanical an explanation of the phenomenon ? Might
Leloun, 71. not rather be alleged that it is owing to a difference
of affinities which exifts between the particles of colour¬
ing matter and the fubftance which is feparated from
the filk or cotton by the proceffes of bleaching or fcour-
ing. This fubftance probably a£ls the part of a mor¬
dant ; and having a ftronger affinity for the fluff and
for the colouring matter than the fluff has for the lat¬
ter, the colour communicated is more durable when
filk or cotton is dyed in the unbleached or unfcoured
ftate.
Prepara- j 20. To prepare cotton fluffs for receiving the dye, fe-
tions for veral operations are neceffary. It mull firft-.undergo the
procefs of fcouring. By fome it is boiled in four water,
or in alkaline ley. It fhould be kept boiling for two
hours, then wrung out, and rinfed in a ftream of water
till the water comes off clear. The fluffs to be pre¬
pared fhould be foaked for fome time in water, mixed
with not more than y— part of fulphuric acid, and then
carefully w’afhed in a llream of water, and dried. In
this operation the acid combines with a portion of
calcareous earth andiron, which would have interrupt¬
ed the full effect of the colouring matter in the procefs
of dyeing.
Aluming. x 21. Aluming is another preliminary procefs in the
dyeing of cotton. The alum is to be diffolved in the
manner already defcribed, in preparingfilk. Each pound
of cotton fluff requires four ounces of alum. By fome
a folution of foda, about -j^th part of the alum, and
by others, a fmall quantity of tartar and arfenic are ad¬
ded. The thread is to be impregnated by working it
in fmall quantities with this folution. The whole is
then put into a veffel, and the remaining part of the
I N G. 411
liquor is poured upon it. In this ftate it is left for 24. Of Sub¬
hours, after which it is removed to a ftream of water,
and allowed to remain for an hour and a half, or two e(j
hours, to extradl part of the alum. It is then to be —v——J
vvaffred. By this operation, cotton is found to gain an
addition of about ■jo-1!1 part of its weight.
122. The operation of galling is another preparatory Galling,
procefs in the dyeing of cotton fluff's. The quantity of
aftringent matter employed muft be proportioned to its
quality, and the amount of the eff’eft required. Pow¬
dered galls are boiled for two hours in a proportion of
water, regulated by the quantity cf thread to be galled.-
This iolution being reduced to fuch a temperature as
the hand can bear, is divided into a number of equal
parts, that the thread may be wrought pound by pound.
The whole fluff is then put into a veffel, and the re¬
maining liquor poured upon it, as in the former pro¬
cefs. It is then left for 24 hours, if it is to be dyed
black, but for other colours, 1 2 or 15 hours are found
fufficient. It is then wrung out and dried.
In the galling of cotton fluffs, which have already
received a colour, the precaution fhould be obferved of
performing this operation in the cold, otherwife the co¬
lour is fubjedl to injury.
1 23. Bertholletinforms’us, that cotton which has been
alumed acquired more weight in the galling than that
which had not previouffy undergone that procefs ; for
although alum adheres but in fmall quantities to cotton,
it communicates to it a greater power of combining,
both with the aftringent principle, and with the colour¬
ing particles. This, we may add, may be confider-
ed as a good inftance of the aflion of intermediate
affinities, and of the advantage to be derived to the art
of dyeing, from inveftigating and obferving this ac¬
tion.
Sect. IV. 0/Flax.
124. Flax and hemp nearly refernble each other in Origin,
their general properties’, and fo far as relates to the pro¬
ceffes of dyeing, what is faid of the one may be ap¬
plied to the other. Flax or lint is obtained from tbe
bark of Linum u/tati/jimum, and hemp from that of
Cannabis fativa.
125. Before flax is properly prepared to receive the Watering
dye, it muft be fubjefted to feveral proceffes. One of the
moft important is that of watering, by which the fi¬
brous parts of the plant are feparated, and brought to
that ftate in which they can be fpun into threads. As
the quantity and quality of the product depend much
on this preliminary operation, it becomes of the great-
eft confequence that it be properly condufled. During
this procefs, carbonic acid and hydrogen gas are given
out. The extrication of thefe gafes is owing to a glutin¬
ous juice which holds the green colouring part of the
plant in folution, and which is the medium of union
between its cortical and ligneous parts, undergoing a
certain degree of putrefaftion. This fubftance feems
to referable the glutinous part which is held diffulved
in the juice obtained from plants by preffure ; is fe¬
parated from the colouring particles by means of heat j
readily becomes putrid, and by diftillation affords-am¬
monia. But although it is held in folution with the
expreffed juice, it would appear that it cannot be fe¬
parated from the cortical parts completely, by means
of water ; and hence it happens, that hemp or flax
3 B 2 watered
Strudiure.
412 DYE
Operations watered in too ftrong a current, has not the requifite
of Dyeing.^ f0f^-nefs an(i flexibility. But on the other hand, if the
xvater employed in this operation be flagnant and in a
putrid flate, the hemp or flax becomes of a brown co¬
lour, and lofes its firmnefs. In the one cafe, the pu-
trefadlive procefs is interrupted ; in the other it is con¬
tinued too long, and carried too far. This procefs,
therefore, is performed with the greateft advantage in
places near the banks of rivers, where the water may
be changed fo frequently as to prevent fuch a degree
of putrefaftion as would Be injurious to the flax, as
well as prejudicial to the workmen, from noxious
exhalations’, and, at the fame time, not fo frequent¬
ly as to retard or interrupt thofe changes which are
neceflary for rendering the glutinous fubftance foluble
in water.
126. By the procefs of watering flax, and by drying
before and after that procefs, the green coloured par¬
ticles undergo a fimilar change to that which is obfer-
ved in the green fubltance of the plants expofed to the
aftion of air and light. The next part of the1 procefs,
therefore, after watering, is to fpread it out upon the
grafs, and thus expofe it for fome time to the air and
fun. By this means the colour of the lint is im¬
proved, and the ligneous part becomes fo brittle,
that it is eafily feparated from the fibrous part.
This operation, as is well known, is ufually performed
by machinery.
127. The fibres of lint poflefs no perceptible degree
of elafticity, and they appear to be perfe&ly fmooth.
No roughnefs or inequality can be detefted by the
feel, and no afperities can be perceived, even with the
afliflance of the microfcope. Experience (hows, that
it produces no irritation on wounds or fores which are
dreffed with it, as is known to happen from a fimilar
application of cotton fluffs.
1 28. Flax which is intended for dyeing muft be fub-
jefted to a fimilar feries of operations with cotton in
the different proceffesof fcouring, aluming and galling.
A repetition of the mode of performing thefe opera¬
tions is therefore unneceffary.
Chap. IV. Of the Operations of Dyeing.
129. Before "we proceed to the detail of the proceffes
of dyeing, we fhall throw out a few hints on the opera¬
tions in general, fome of which may perhaps be ufeful
to the pradlical dyer.
Advantages 130* ^ie v''or^s which are carried on in extenfive ma-
of large ° nufaftories, it has been obferved, are followed with ad-
manufafto- vantages which are unknown to thofe which are con-
r^e*’ duffed on a limited fcale or in a detached manner.
By the fubdivifion of labour each workman direfling
his attention to one or a few objeffs, acquires a great
facility and perfection of execution, by which means
the faving of time and labour becomes conliderable.
This principle is particularly applicable to the art of
dyeing, becaufe the preparation which remains after one
operation may often be advantageoufly employed in
another. A bath from which the colouring matter
has been in a great meafure extrafted in the nrft ope¬
ration, may be ufeful as a ground for other fluffs, or
with the addition of a freflr portion of ingredients may-
form a new bath. The galls which have been applied
to the galling of filk may anfwer a fimilar purpofe for
Prepara
tion for
dyeing.
I N G. Part L
cotton or wool. From this it muft appear that the Operations
limitations and reflriClions under which the art of dye- Eyeing,
ing labours in fome countries muft tend to obftruft its v
progrefs and improvement. An extenfive plan of ope¬
rations, by which the different branches of the art are
conneffed together, would effeflually prevent the lofs
of ingredients, time, fuel, and labour.
131. A dye-houfe, which ftiould be let down as near Dye-houfes.
as poffible to a ftream of water, fhould be fpacious and
well lighted. It fhould be floored with lime and pla-
fter *, and proper means fhould be adopted to carry off
•water or (pent baths by forming channels or gutters,
fo that every operation may be conducted with the ut-
moft attention to cleanlineis.
132. The lize and pofition of the caldrons are to be Caldrons,
regulated by the nature and extent of the operations
for which they are defigned. Excepting for fcarlet
and other delicate colours, in which the tin is ufed as a
mordant, in which cafe tin veffels are preferable, the
caldrons fliould be of brafs or copper. Brals, being lefs
apt than copper to be afted on by means of chemical
agents, and to communicate fpots to the fluffs, is fitter
for the purpole of a dyeing veffel. It is 1’carcely ne-
ceffary to fay that it is of the greateft confequence that
the coppers or caldrons be well cleaned for every ope¬
ration ; and that veffels of a large fize fhould be fur-
nifhed at the bottom with a pipe and ftop-cock for the
greater conveniency of emptying them: and there muft;
be a hole in the wail or chimney above each copper to
admit poles for the purpofe of draining the fluffs which
are immerfed, fo that the liquor may fall back into the
veffel, and no part may be loft.
133. Dyes for filk where a boiling heat is not found Apparatus
neceflary, are prepared in troughs or backs, which are for filk.
long copper or wooden veflels. The colours which
are ufed for filk are extremely delicate. They muft:
therefore be dried quickly, that they may not be long
expofed to the a£l!on of the air, and there may be no
rifk of change. For this purpofe, it is neceffary to have
a drying room heated with a flove. The filk is ftretch-
ed on a moveable pole, which by the dyers is called
a (baker. This is hung up in the heated chamber,
and kept in conftant motion to promote the evapora¬
tion.
134. For pieces of fluffs, a winch or reel muft be For ilufis
conflru£led } the ends of which are fupperted by twoofcloth’
iron forks which may be put up at pleafure in holes
made in the curb on which the edges of the copper
reft. The manipulations in dyeing are neither diffi¬
cult nor complicated. Their object is to impregnate
the fluff to be dyed with the colouring particles, which
are diffolved in the bath. For this purpofe, the a&ion
of the air is necefiary, not only in fixing the colouring
particles, but alfo in rendering them more vivid j while
thofe which have not been fixed in the fluff are to be
carefully removed. In dyeing whole pieces of fluff, or a
number of pieces at once, the winch or reel mentioned
above, muft be employed. One end of the (luff is firft
laid acrofs it, and by turning it quickly round, the
whole paffes fucceffively over it. By turning it after¬
wards the contrary way, that part of the fluff which was
firft immerfed, will be the Laft in the fecond immerfion,
and thus the colouring matter will be communicated
as equally as poffible.
135. In dyeing wool in the fleece, a kind of broad For woai
ladder
Chap.
Wringing
out.
Raking.
Giving a
ground.
Dipping.
Terms for
different
lhades.
  XV. DYE
Operationsladde^ with very clofe rounds, called by the dyers of
of Dyeing. thjs country,' z fcraw, ov ferny, is ufed. This is pla-
' ' ced over the copper, and the wool is put upon it, for
the purpofe of draining and expofure to the air, or
when the bath is to be changed. If wool is dyed in
the flate of thread, or in Ikains, rods are to be paffed
through them, and the hanks turned upon the fkam
fticks& in the liquor. This is called flaking over.
When filk or thread is in the fame date, it undergoes
a fimilar operation.
136. To feparate the fuperabundant colouring par¬
ticles, or thofe which have not been fixed in the fluff,
filk or thread, after being dyed, it muft be wrung out.
This operation is performed with a cylindrical piece of
wood, one end of which is fixed in the wall, or in a
poft. *This operation is often repeated a number of
times fucceffively, for the purpofe of drying the fluffs
more rapidly, and communicating a brighter luftre.
137. When, after a certain quantity of frelh ingre¬
dients is added to a liquor, and it is ftirred about, it is
faid to be raked, becaufe it is mixed with the rake.
I 38. In dyeing, one colour is frequently communi¬
cated to fluffs, with the intention of applying another
upon it, and thus a compound colour is produced.
The firff of thefe operations is called giving a ground.
139. When it is found neceffaryto pafs fluffs feveral
times through the fame liquor, each particular operation
is called a dip.
140. A colour is faid to be rofed, when a red co¬
lour having a yellow tinge, is changed to a fhade in¬
clining to a crimfon or ruby colour and tne conver-
fion of a yellow red to a more complete red, is called
heightening the colour.
141. In addition to thefe general remarks, we might
give more minute details of the different operations
which are employed in dyeing ; but as r-ve cannot pre¬
fume that they would be of much advantage to the
practical dyer, we (hall not indulge ouilelves in ufe-
lefs defeription. “ Although the manipulations of dye¬
ing,” fays Berthoilet, are not very various, 'and ap¬
pear extremely Ample, they require very particular at¬
tention, and an experienced eye, in order to judge
of the qualities of the bath, to produce and fuflain the
degree of heat fuited to each operation ; to avoid all
circumftances that might occafion inequalities of co¬
lour, to judge accurately whether the fhade of what
comes out of the bath fuits the pattern, and to efta-
* jE/fw. of blifh the proper gradations in a ieries of fhades”*.
Dyeing. J^2t We (hall conclude this chapter with a few ob-
YVater im- Nervations on the qualities and efffas of different kinds
portant!”1' of water, which may be confidered as one of the moft
effential agents in the art of dyeing. It is almoft un-
neceffary to fay, that water which is muddy, or con¬
tains putrid fubffances, fhould not be employed j and
indeed* no kind of water which poffeffes qualities dif-
tinguifhed by the tafte, ought to be ufed. Water
which holds in folution earthy falts, has a very confi-
derable aftion on colouring matters, and it is chiefly
by means of thefe falts. Such, -for inftance, are the
nitrates of lime and mag'nefia, muriate of lime and
magnefia, fulphate of lime, and carbonate of lime and
of magnefia.
143. Thefe falts which have earthy bafes, oppofe the
folution of the colouring particles, and by entering in¬
to combination with many of them, caufe a precipita-
2
1 N G. 4'J
tion, by which means the colour is at one time deeper
and at other times duller and more faint tnan woum 1
o^herwife be the cafe. Water impregnated with the
carbonates of lime and magnefia, yield a precipitate
when they are boiled ; for the excefs of carbonic acid
which held them in folution is driven off by the heat ;
the earths are thus precipitated, and adhering to the
fluffs to be dyed, render them dirty, and prevent the
colouring matter from combining with them.
144. It is of much confequence to be able to dn-
tinguiffv the different kinds of water which come under
the denomination of hard water, that they may be a-
voided in the effential operations of dyeing *, but to de¬
left different principles contained in fuch waters, and to
afeertain their quantity with precifion, require great
{kill, and very delicate management of chemical ope¬
rations, which the experienced chemift only can be fup-
pofed to poffefs. For the methods to be followed when
fuch accuracy is required, we muft refer to the analyfis
of mineral waters, of which a full view is given in
the treatife on chemiftry, and content ourfelves with
mentioning fome fimple tefts which are of eafy ap¬
plication.
145. One of thefe tefts is the folution of foap, by
which it may be difeovered whether water contains lo
large a portion of any of thefe faline matters as may be
injurious to the proceffes. Salts which have earthy
bafes, have the property of decompofing foap by the
aftion of double affinity. The acid of the fait combines
with the alkali of the foap, and remains in folution,
while the earth of the fait and the oil of the foap enter
into combination, and form an earthy foap which is
infoluble in water, and produces the curdling appear¬
ance which is the conlequence of this new combina¬
tion. Water, then, which is limpid and not ftagnant,
which has no perceptible tafte or fmell, and has the
property of diflolving foap without decompofttion,
may be conftdered as fufficiently pure for the pro¬
ceffes of dyeing. All waters which poffefs thefe
qualities will be found equally proper for thefe pur¬
poses.
146. But, as it is not always in the power of the Method o£
dyerto choofe pure water, means of correfting the water purifying,
which would be injurious to his proceffes, and particu¬
larly for the dyeing of delicate colours, have been pro-
pofed. Water in which bran has been allowed to be¬
come four, is moft; commonly employed for tins pur¬
pofe. This is known by the name of fours, or four
water. The method of preparing four water is the fol¬
lowing. Twenty four bufhels of bran are put into a
veffel that will contain about 10 hogfheads. A large
boiler is filled with water, and when it is juft ready to
boil, it is poured into the veffel. Soon alter the acid
fermentation commences, and in about 24 hours the li¬
quor is fit to be applied to ufe. Water which is im¬
pregnated with earthy falts, after being treated in this
way, forms no precipitate by boiling. It is probable
that the four water decompofes the carbonate of lime
and magnefia, becaufe the vegetable acid which is
formed during the fermentation, combines with the
earthy bafis, and fets the carbonic acid at liberty.
147. Some of the fubftances with which waters are
impregnated, or thofe which are merely diffufed in
them in a ftate of very minute divifion, may be fepara-
ted by means of mucilaginous matters. The mucilage
coagulates
4H DYE
Pg^Cof coagulates by means of heat, ami carrying with it the
ear^hs kparated by boiling, as well as thofe fubftances
which are limply mixed with the water, and render it
turbid, rifes to the furface, and forming a fcum, may be
ealily removed.
148. Saline matters having earthy bafes, which in
general are injurious in dyeing, may in fome cafes
be ufeful, becaufe by their aftion, modification^ of dif¬
ferent colours may be produced. A water of this kind,
lor inftance, would have the effe£l of communicating
to the colour of cochineal a crimfon lhade.
149. River water, which is apt to be impregnated
^ Part II.
witn earthy falts, may, at different times contain very Practice of
different proportions of thefe falts $ and although the Dyeing,
dyer may follow exa&ly the fame procefs, he may be
furprifed to find confiderable variations in the (hades of
his colours. This arifes from the different degrees of
impregnation with thefe faline matters which the wa¬
ter undergoes, as the bed of the river is of greater or
lefs extent, or the waters flow over thole places from
which they derive thefe earthy falts. To obtain the
fame rei'ult in the procefs, therefore, it would be necef-
fary to make certain variations according to the ftate
of impregnation of the water.
PART II. OF THE PRACTICE OF DYEING.
150. IN the preceding part, we have endeavoured
to give a general view of the principles on which the
art of dyeing depends. We have confidered the phy-
fical and chemical properties of colours and colouring
matters; the nature of the fubftances to w hich colours
are communicated, and the agents or means by which
this is effected ; and from the experiments and obler-
vations of philolophers, whofe inveftigations have been
dire&ed to this fubjeft, it appears that thefe changes
are entirely owing to chemical affinities, by which de-
compofitions are effefted, and new combinations form¬
ed, among the conftituent parts of the fubftances em¬
ployed. A precife and full knowledge of the effects
of thefe chemical agents would render the theory of
dyeing complete j and although much has been already
done by the chemical philofophers whom we have had
occafion frequently to quote, yet experiments and ob-
fervations are dill wanting to form a theory of this art
on fixed and rational principles. This, it is obvious,
can only be done by chemical inveftigations. To the
ofchemdtC Pra<^*ca^ d.yer. therefore, the ftudy of chemical fcience
ry in dye-* muft k® efl5nttally requifite, as this only can be hi%
ing. true guide in eftimating and managing the complicated
changes in the different proceffes of his art. It is on¬
ly by the application of the principles of cbemiftry
that this art can be improved and perfected. But the
application of thefe principles muft be made by the
practical dyer himfelf, not by the chemift in his labo¬
ratory, or during an occafional vifit to the manufa&ory.
For in the complicated proceffes of dyeing conduced
on an extenfive fcale, a thoufand circumftances will be
overlooked by the moft acute and difeerning chemift,
which will not efcape the habitual obfervation of the
philofophical artift. Convinced ourfelves of the incal¬
culable advantages which the art of dyeing may de¬
rive from chemical fcience, and the innumerable re-
fources which ingenuity and addrefs may difeover in
the proper application of its principles towards the im¬
provement of the different proceffes of this art, we (ball
not be thought, we hope, too fanguine in looking for¬
ward to a degree of perfection which is little to be ex¬
pected from its prefent ftate.
The proceffes of the art of dyeing form the fubjeCt of
the fecond part of this treatife, the confideration of
which we are now to enter upon.
•Bivifion of 151. Colours have been ufually diftributed by dyers
colours. jnto two clafles. Thefe have been denominated Jimple
and compound colours. Simple colours, which are com¬
monly reckoned four in number, are fuch as cannot be
produced by the mixing together different colours.
Colours denominated compound may be produced by
the mixture of any two of the fimple colours in dif¬
ferent proportions. Thus red, yellow, and blue are in¬
capable of being produced by any combination of
others, and are therefore confidered as fimple colours.
Blue and red, w'hich compofe a purple, blue and yel¬
low, a green, and red and yellow, an orange, are
compound colours ; but none of thefe, by any compo-
fition whatever, will afford a red, yellow, or blue.
152. Dr Bancroft in his elaborate treatife on the p
philofophy of permanent colours, divides colouring croft-^”"
matters into tw’o claffes. The firft includes thofe co¬
louring fubftances which, being in a ftate of folution,
may be permanently fixed on any ftuff without any
mordant, or the intermediate aftion of earthy or me¬
tallic bafes. In the fecond clafs are comprehended
thofe matters which cannot be fixed without the aflion
of mordants. The firft he has denominated fubflantivc
colours ; becaufe the colour is fixed without the aid of
any other body ; and the fecond adjettive; becaufe
they become permanent only with the addition of a
mordant. The celebrated purple produced by the
liquor obtained from Ihell-filh and indigo, are examples
of fubftantive colours. Prulfian blue and cochineal
are adjective colours.
The ufual divifion of‘colours into fimple and com¬
pound feems to form an arrangement equally conveni¬
ent and perfpicuous. We lhall therefore adopt it in
the following chapters. In the firft we lhall treat of
Jbmple colours ; in the fecond of compound colours j and
to thefe we {hall add a third chapter on topical dyeing,
or calico printing.
Chap. I. Of Simple Colours.
153. Simple colours, we have already obferved,Sjmpie co.
are iuch as cannot be produced by the mixture of other lours,
colours. They are the foundation of all other colours,
and therefore come naturally to be firft treated of.
The fimple colours are four, viz. 1. Red. 2. Yellow.
3. Blue. 4. Black. To thefe a fifth is added by fome ;
namely, brown, or fawn colour •, although it may be
produced by the ccmbin ition of other colours. The
nature of the colouring lubltances which are employed
to
Chap. I. DYE
Of Simple to produce thefe colours, and the procefles by which
Colours, are fixe(j on feveral fluffs, will form the fub-
"" " ^ * jefts of the four following fetdions.
Sect. I. Of Red.
154.. Red colours, from different degrees of intenfi.
ty, have received different names, as crimfon, fcarlet,
befides a great variety of fhades which are Ids ftriking,
and come under no particular denomination. In this
fed ion we (hall treat of the nature and properties of the
fubflances which are employed in dyeing red, and then
give an account of the different proceffes which are
followed in fixing thefe colouring matters on animal
and vegetable produdions.
1. Of the Subfances employed in Dyeing Red.
The colouring matters which are principally em¬
ployed in dyeing red, are madder, cochineal, hermes, lac,
archil, carthomus, hr aft! wood, and logwood.
Madder. Madder is very extenfively employed in dye¬
ing. It i^the root of a plant {rubia tinSatum, Lin.)
of which there are two varieties. It is cultivated in
different parts of Europe, and the beft, it is faid, is
brought from Zealand. Madder, as it is prepared for
dyeing, is diftinguilhed into different kinds. What is
called grape madder, is obtained from the principal
roots 5 the none grape is produced from the ftalks,
which by being buried in the earth, are converted in¬
to roots, and are called layers. When the roots are
gathered, thefe layers are feparated, with fuch of the
fibres of the roots as do not exceed a certain degree of
thicknefs, as well as thofe wdiicb are too thick j the lat¬
ter containing a great deal of woody matter. The
beft roots are about the thicknefs of a goofe quill, they
have fome degree of tranfparency ; are of a reddifli co¬
lour, and have a ftrong fmell, and a fmooth bark.
When the madder is gathered, it muft be dried, to
render it fit for being reduced to powder, and being
preferved. This operation is performed in warm cli¬
mates in the open air. In Holland, ftoves are employ¬
ed for th'e fame purpofe; but when treated in this way,
it is often injured, from too great a degree of heat,
and being mixed with particles of foot. The fuperi-
ority of madder from the Levant is aferibed to its
having been dried in the open air.
Prepara- 156. The roots being dried, and the earthy matters
tion. which adhere to them being feparated, by (baking
them in a bag, or beating them lightly on a wooden
hurdle, they are reduced to pow'der, by means ot ma¬
nual labour, or with the aid of machinery. All the
parts of madder do not yield the fame colouring mat¬
ter. The outer bark, and the ligneous part within,
give a yellowifti dye, which injures the red, Thefe
parts may be feparated in confequence of the different
degrees of facility with which they are reduced to
powder. The outer bark and woody parts are more
eafily powdered than the parenchymatous parts, which
contain the fine red dye. To effect the feparation of
thefe different parts, three operations are performed.
After the firft, the madder is paffed through a fieve, by
which, what is called the fhort madder, (courte of the
French), intended for tan, and inferior colours, is ob¬
tained. What remains is again ground and fifted.
What the French call mirobee, is obtained by this
1 N G. 415
operation. A third operation of the fame kind affords Of Simple
the robee, or finer kind of madder. Coiour*.
157. The refult of the experiments of D’Am-
bourney fhew, that the frefh root of madder may be
ufed with as much advantage in dyeing, as when it is
dried and powdered. Four pounds of frelh madder,
he obferved, are equal to one of the dry, although in
drying it lofes feven-eighlhs of its weight. When the
frefh roots are to be ufed, they are to be well wafhed
in a current of water, immediately after they are taken
out of the ground, and afterwards cut into pieces and
bruifed. In dyeing with the frefh roots, allowance
fhould be made for tht quantity of water which they
contain, fo that a fmaller proportion fhould be put into
the bath. Beckmann feems to be of the fame opinion
with regard to the ufe of the frefh roots cf madder,
and yet he has frequently obferved that it is more fit
for dyeing after it has been preferved for two or three
years.
158. The madder which is cultivated in the neigh¬
bourhood of Smyrna, and in the ifland of Cyprus,
affords a brighter red than the European madder, and
therefore it is preferred in the preparation of the
yldnanople red. This is known by the name lizari.
Berthollet informs us that it is cultivated in Provence
in France, and Beckmann has been very fucccfsful in
raifing it at. Gottingen.
159. The colouring matter of madder is foluble in Propertic*.
alcohol, and by evaporation a deep-red refiduum is
formed. In this folution fulphuric acid produces a
fawn-coloured precipitate j fixed alkali, one of a violet
colour, and the fulphate of potafh, a precipitate of a
fine red. Alum, nitre, chalk, acetate of lead, and
muriate of tin, afford precipitates in the folution of
madder in alcohol, of various fhades. The colouring
matter of madder is alfo foluble in water. By mace¬
ration in feveral portions of cold water fucceiTively,
the laft receives only a fawn colour, which appears en¬
tirely different from the peculiar colouring particles of
this fubftance. It refembles what is extrafted from
woods and other roots, and perhaps exifts only in the
ligneous and cortical parts. By repeated boiling, Ber¬
thollet exhaufted the madder of all its colouring par¬
ticles which are foluble in water. It ftill retained,
however, a deep colour, and yielded a confiderable
quantity of colouring matter to an alkali. There rvas an
inconfiderable refiduum, which flill remained coloured.
The pulp, therefore, appears entirely compofed of co¬
louring matter, part of w hich is infoluble in fimple water.
When oxy muriatic acid is employed in fufficient quantity,
to change an infufion of madder from red to yellow', it
produces a fmall portion of a pale-yellow precipitate j
the fupernatant liquor is tranfparent, and retains more
or lels of a deep yellow colour, according to the pro¬
portion and ftrength of the acid. Double the quantity
of acid is required to difeharge the colour of a decoc¬
tion of madder of what is neceffary to deftroy that of
the fame wreight of Brazil wood. This fhews that the
colouring matter of madder is more durable than that
of Brazil wood. The infufion of madder in water is
of a brownifh orange colour. The colouring matter
may be extracted, either by hot or cold water; in the
latter the colour is moft beautiful. The deco&ion is
cf a brownifh colour. The colouring matter of mad¬
der*
416 DYE
Of Simple der cannot be extra&ed without a great deal of water.
, Colours. . ounces of madder require three quarts of wTater.
' v~ Alum forms, in the infufion of madder, a deep brown-
iih red precipitate ; the fupernatant liquor is yellowifh,
inclining to browm. Alkaline carbonates precipitate
from this lafl liquor a lake of a blood-reci colour ; with
the addition of more alkali, the precipitate is rediffbl-
ved, and the liquor becomes red. Calcareous earth
precipitates a darker and browner coloured lake than
alkalies. Carbonate of magnefia forms a clear blood*
red precipitate, which by evaporation produces a
bfood-red extract, foluble in water. The folution of
this extra£l is employed as a red ink, but it becomes
yellow by expofure to the fun. Metallic falts alfo form
precipitates in a folution of madder. The precipitate
with acetate of lead is of a brownilh red colour ; with
nitrate of mercury and fulphate of manganefe, a pur-
plifh brown j with fulphate of iron, a fine bright
brown.
Cochineal. Cochineal, which furnifhes a valuable dye fluff,
and about the nature of which there was at firft a good
deal of uncertainty, is an infeft. It is produced on
different fpecies of the caflus, or Indian fig. Themoft
perfect variety of the cochineal infeft is that which
breeds on the caftus coccinillifer, Lin. To this plant
liiftory. t])c Mexican Spaniards give the name of nopal. When
the Spaniards firft arrived in Mexico, they faw the
cochineal employed by the native inhabitants, in com¬
municating colours to forae part of their habitations,
ornaments, and in dyeing cotton. Struck with its
beautiful colour, they tranfmitted accounts of it to the
Spanifh miniftry, who about the year 1523, ordered
Cortes to diredl his attention to the propagation of this
fubftance. The inhabitants of Europe were long mif-
taken concerning the nature and origin of cochineal,
by fuppofing it to be the grain or feed of a plant.
This opinion was firft contrsdi£fed in a paper publifh-
ed in the third volume of the Philofophical Tranfac-
tions,. in 1668, and four years afterwards, Dr Lifter,
in the feventh volume of the fame work, throws out a
con}e<fture, that cochineal may be a fort of kermes.
Different opinions concerning the origin of this fub¬
ftance were entertained, till about the beginning of the
year 1757, Mr Ellis obtained fome of the joints of the
plant on which the infedls breed, from South Carolina,
and prefented them the fame year to the Royal Society.
Thefe fpecimens, Mr Ellis obferves, were full of the
nefts of this infeft, in which it appeared in its various
ftates, in the moft minute when it walks about, to
the ftate when it becomes fixed, and wrapt up in a fine
web, which it fpins about itfelf. With the affift-
ance of the microfcope, Mr Ellis difcovered the true
male infett in the parcels which had been fent to him
from America-, and in Auguft 1759, in confequence
of Mr Ellis’s difcovery, Dr Garden caught a male co¬
chineal fly, which he obferves is rarely to be met with.
I N G. Part IF.
He fuppofes that there may be 150 or 200 females for OfSimpIe
one male. Thefe difcoveries proved indifputably, that c°lours.
the cochineal is an animal prcduflion *. ^TprTr^
j6i. The body of the female infedl is flat on the Tranf.'
belly, and hemifpherical on the back, and tranfverfcly vol. lii.
wrinkled. The {kin is dark brown it has no wing ,
but is furniflied with fix fiiort brown legs. The body
of the male, which is of a deep red colour, is rather
long, and covered with two wings, extending horizon¬
tally, and crofting a little upon the back. It has two
fmall antennae, and fix legs, which are larger than
thofe of the female. It has a fluttering kind of mo¬
tion. The life of the male is only of a month dura¬
tion, but the fecundated female lives a month longer.
The female is fometimes oviparous and fometimes vi¬
viparous ; but this is not a peculiarity confined to this
infect. It belongs to fome others, and feems to be re¬
gulated by the temperature and feafon of the year.
The female cochineal inftcl adheres to the fame fpot
of the tree on which it is produced during her whole
life. As foon as the female is delivered of its nume¬
rous progeny, it becomes a mere hulk and dies. In
Mexico it is therefore an objeft of great importance
to prevent this, and to collect them in the fecundated
ftate. For this purpofe they are picked from the
plants, put into a linen bag, which is immerfed in hot
water, to deftroy the life of the young infecfts, and
then carefully dried. In this ftate they are imported
into Europe.
162. There are two kinds of cochineal. The heft, Varieties,
or domefticated kind, is called by the Spaniards, gra¬
nd Jina. This variety breeds upon the caBus coccinilli-
fer, or nopal j and being of a larger fize, and contain¬
ing a greater proportion of colouring matter, it is always
preferred. The other variety is the grana fylvejlra of
the Spaniards, or wild cochineal. It is produced from
other fpecies of the caBus. It is fmaller than the
other, and as it is covered with a downy matter, pro¬
duced by the infeft to defend itfelf againft the cold,
this increafes the weight, but is of no ufe in dyeing.
An equal weight of the wild cochineal yields a fmaller
quantity of colouring matter, and is therefore lefs va¬
luable. It ought, however, to be obferved, that it
can be reared with greater facility, and at much lefs '
expence and when it is bred upon the nopal, it ac¬
quires double the fize, and has a fmaller quantity of
downy matter for its covering, fo that it approaches,
by this management, to the nature of fine cochineal.
163. As the quantity of cochineal confumed in Eu¬
rope is very great (d), and as the Spaniards have hi¬
therto enjoyed the exclufive advantages of rearing and
fupplying the market with this valuable fubftance, it
has become an object with other nations to {hare them.
Attempts have therefore been made to form eftablifli-
ments for rearing thefe infects in thofe colonies whofe
foil and climate leem fuitable for the purpofe.
164.
(d) The average quantity, fays Dr Bancroft, of fine cochineal annually confumed in Europe, amounts to
about 3000 bags, or 600,000 lbs. weight, of which about 1200 bags, or 240,000 lbs. weight may be confider-
ed as the prefent annual confumption of Great Britain. A greater quantity comes into the kingdom, but the
furplus is again exported to other countries. Thefe 1200 bags may be fuppofed to coft 180,cool, fterling, va¬
lued at 15 s. per lb. which has been about the average price for fome years paft. Philofophy of Permanent Co-
loiirS) p. 258,
Chap. I. DYE
Of Simple 164. One of the mofl: fuCcefsful of thefe attempts
Colours, was niade by M. Thiery de Menonville, in 1777. He
Attervjts ' exP°fe(i himielf to great danger, by going to Mexico,
to culti- he might obferve the mode of rearing the cochi-
vate it. neal infe£l, and procure that valuable produ6fion, to
plant it in St Domingo. He proceeded by the Ha-
vannah to La Vera Cruz, where he was informed that
the fineft cochineal infefts were reared at Guaxaca, 70
leagues diftant. On the pretence of ill health, he re¬
ceived permiffion to ufe the baths of the river Magda¬
lene : but inllead of accepting this privilege, which
was not his objeft, he diredted his courfe, not with¬
out much difficulty and danger, to Guaxaca *, where
having obtained the information he wanted, and hav¬
ing purchafed a quantity of nopals, covered with the
infects of the fine or domeltic breed, which he pretend¬
ed were of great ufe in preparing an ointment for his
feigned diforder, the gout, he put them into boxes
along with other plants, and lucceeded in bringing
them away without notice or fufpicion. On his return,
he was driven by a ftorm into the bay of Campeachy,
where he found a living cadtus of a fpecies which was
fit for the nourifliment of the fine cochineal. He re¬
turned in fafety towards the end of the fame year, to
St Domingo, with his prize, and immediately formed
a plantation of nopals, with the view of propagating
both varieties of the cochineal. Soon after his return,
he found the wild kind living naturally on the caBus
perejhia, a native of that ifland. Unfortunately, how¬
ever, for the eftablilhment, Thiery de Menonville died
in the year 1780, through difappointment and vexa¬
tion, it is faid, at feeing his patriotic endeavours fp
little affifted, and his fervices fo fparingly rewarded by
government j and foon after his death, the fine cochi¬
neal periffied. But the dilcovery of the wild kind in
St Domingo was not neglefted. M. Bruley fucceed-
ed in his attempts to rear this fpecies of cochineal. A
pofthumous work of Thiery de Menonville was pub-
liffied by the Royal Society of arts and fciences at Cape
Francois, containing minute inftruftions with regard
to every thing refpefting the cultivation of the nopal,
and the other fpecies of caflus, which may be more or
lefs fuccefsfully fubftituted for breeding or rearing the
cochineal. Of this Berthollet has given an extract in
the 5th volume of the Annales de Chimie. Some of our
own countrymen, a lew years ago, fucceeded in pro¬
curing fome of the fine cochineal infe&s ; and attempts
have been made, wdth what fuccefs we know not, to
rear them in the Eaft Indies.
Properties. I^5* Fnm cochineal, if it has been properly pre¬
pared and kept, ought to be of a gray colour, with a
lhade of purple. The gray colour is owing to a pow¬
der with which it is naturally covered, and part of
wffiich it Hill retains. The colouring matter extracted
by the water in which the infe& has been killed, pro¬
duces the purple lhade. In a dry place, cochineal
may be kept for a long time, without lofing any of its
properties. Hellot made experiments on cochineal 130
years old, and found that it produced the fame effedl
Vol. VII. Part II.
I N G. 417
as if it had been quite new. Cochineal yields Its co- Of Simple
louring matter to water and the decoflion, wffiich is ^oJours*
of a crimfon colour, inclining to violet, may be kept1
for a long time, without lofing its tranfparency, or
becoming putrid. If this decodlion be evaporated, and
the refiduum or extraft be digelted in alcohol, the co¬
louring part diflblves, and leaves a refiduum of the co¬
lour of wine lees, of which frefh alcohol cannot, de¬
prive it. The alcohol of cochineal affords, by evapo¬
ration, a tranlparent refiduum of a deep red, which
being dried, has the appearance of a refin. A fmall
quantity of fulphuric acid added to the decoftion of
cochineal, produces a red colour, inclining to yellow',
and a fmall quantity of a beautiful red precipitate.
With muriatic acid the fame change is produced, but
there is no precipitate. A folution of tartar converts
the decodlion to a yellowdfh red colour. A precipi¬
tate of a pale red colour is flowdy formed, and the iu-
pernatant liquor remains yellow7 ; but with the addition
of an alkali becomes purple. With the yellow liquor,
folution of tin forms a rofe-coloured precipitate $ folu¬
tion of alum brightens the colour of the infufion, gives
it a redder hue, and produces a crimfon precipitate.
With a mixture of alum and tartar the colour is bright¬
er, more lively, and inclines to ayellowilh red. Mu¬
riate of tin occafions a copious fediment of a beautiful
red. The fupernatant liquor is colourlefs and tranfpa-
rent, and no change is produced on it by adding an
alkali. Sulphate of iron forms a brown violet precipi¬
tate, and the fupernatant liquor remains clear, with a
flight darkifh hue. Sulphate of zinc gives a deep vio-
let precipitate ; the fupernatant liquor remains colour¬
lefs and tranfparent. The precipitate with fulphate of
copper is of a violet colour, and forms ilowly : the fu¬
pernatant liquor is alfo violet and tranfparent. Acetate
of lead gives a purple violet precipitate, and the fuper¬
natant liquor remains limpid.
166. The experiments of Berthollet and Bancroft
fhcw, that the colouring matter of cochineal is not en¬
tirely extra&ed by means of water. Dr Bancroft
found, that after the whole of it which could be ex-
tra&ed by water w7as obtained, by adding a little pot-
aih to the feemingly exhaufted fediment, and pouring on
it frelh boiling water, it yielded a new quantity of co¬
louring matter, equal to one-eighth of what had been
given out to the water ; and Berthollet found the fame
effect produced with the addition of tartar j from which
he concludes, that tartar favours the folution of the co¬
louring part of the cochineal.
167. Kermes (g), another animal fubftance, which Kermes.
is extenfively employed in dyejng, is an infe£f, (coccus
ilicis, Lin.) wffiich breeds on a fpecies of oak, (quercus coc¬
ci/era, Lin.) which grows in moft of the fouthern parts
of Europe, and in many parts of Afia. Kermes was Hiftory.
known to the ancients, under the names of coccum
fcarlatinum, coccus bapticus, coccus infeSorius, granum
tinBorium. Kermes is chiefly obtained from Langue¬
doc, Spain, and Portugal. The infers are colle&ed
in the month of Mayor June, when the female, wffiich
3 G alone
(g) This word is fuppofed to have been derived from the Arabic language, and fignifies a little worm, ver-
miculusand from this wre have the word vermilion, the pigment in the manufacture of which it is the principal
ingredient, r
418
DYEING.
Part II.
Of Simple
Colours.
Properties.
I.ac
alone is ufeful, is diftenied with eggs. To deftroy the
young infefrs, the kermes is expofed to the fleam of
vinegtfr for about half an hour, or fteeped in vinegar
for xo or 12 hours. They are afterwards dried on li¬
nen cloths, and brought to market.
168. When the living infeft is bruifed, it gives out
a red colour. The fmell is fomewhat pie*fant ; the
tafte is bitter and pungent. It gives out its colouring
matter both to water and alcohol, to which alfo it im¬
parts its fmell and tafte. The colour is alfo retained
in the extrafl which is obtained, both from the tinc¬
ture, and from the infulion. Kermes is one of the
moft ancient dyeing drugs j and although the colours
which it communicates to cloth are lefs bright and vi¬
vid than thofe of cochineal, and on that account it has
been lefs extenfively employed in dyeing fince the lat¬
ter was known, yet they have been found to be ex¬
ceedingly permanent. The fine blood-red colour which
is to be feen on old tapeftries in different parts of Eu¬
rope, was produced from kermes, with an aluminous
mordant, and feems to have fuffered no change, though
fome of them are 200 or 300 years old. The colour
obtained from kermes was formerly called fcarlet in
grain, becaufe it was fuppofed that the infeft was a
grain •, and from the chief manufaftory having been
at one time in Venice, it was called Venetian fcarlet.
169. Lac is an animal produ&ion which has been
long known in India, and ufed for dyeing filk and
other purpofes. It is the nidus of the coccus lacca, Lin.
and is generally produced on the fmall branches of the
croton lacciferum. Three kinds of lac are well known
in commerce : 1. Stick lac is the fubftance or comb,
in its natural ftate, forming a cruft on the fmall bran¬
ches or twigs. 2. Seed lac is faid to be only the above,
feparated from the twigs, and reduced into fmall
fragments. Mr Hatchett, who has examined this fub¬
ftance with his ufual fkill and precifion, found the beft
fpecimens confiderably deprived of their colouring
matter *. According to the information which he re¬
ceived from Mr Wilkins, the filk dyers in Bengal
produce the feed lac by pounding crude lac into fmall
fragments, and extracting part of the colouring mat¬
ter by boiling. 3. Shell lac is prepared from the cells,
liquified, ftrained, and formed into thin tranfparent
laminae. There is alfo a fourth kind called lump lac,
which is obtained from the feed lac by liquefaCIion,
and afterwards formed into cakes. The beft lac is of
a deep red colour ; when it is pale, and pierced at the
top, the value is greatly diminiftied, for then the in-
feds have left their cells, and it can no longer be of
ufe as a dye fluff.
Properties. 170. The decoCtion of powdered ftick lac in water,
gives a deep crimfon colour. With one-fifth of borax,
lac becomes more foluble in water. Pure foda, and
carbonate of foda, completely diffolve the different
kinds of lac, and produce a deeper colour than that
which is obtained by means of borax. Pure potafh
fpeedily diffblves all the varieties of lac •, the colour
approaches to purple. Pure ammonia and carbonate
of ammonia readily aft on the colouring matter of lac.
Alcohol diffolves a confiderable portion of the lac ;
and, according to Geoffroy, yields a fine red colour.
When the folution is heated it becomes turbid. Sul¬
phuric acid d’ffolves the colouring matter of lac, as
well as muriatic and acetic acids. In the ufe of lac in
Hi (lory.
* Phil:
‘Tranf,
2804.
dyeing, it has been confidered fuperior to kermes, be- Of Simple
caufe it is able to bear the aftion of a folution of tin, Colours. ^
without the colour being changed to yellow.
171. Archil is a vegetable fubftance of great ufe in Archil,
dyeing. It is employed in the form of a pafle, which
is of a red violet colour. It is chiefly obtained from
two fpecies of lichen, roccella and parellus, Lin.
The firft, wdiich is called Canary archil, becaufe
the lichen from which it is prepared grows abun- f
dantly in the Canary iflands, is moft valued. It is
prepared by reducing the plant to a fine pow-der, which
is afterwards paffed through a fieve, and (lightly moif-
tened with ftale urine. The mixture is daily ftirred,
each time adding a certain proportion of foda in pow¬
der, till it acquire a clove colour. It is then put into
a wooden calk, and urine, lime-wTater, or a folution of
fulphate of lime, (gypfum,) is added in fufficient quantity
to cover the mixture. In this ftate it is kept ; but to
preferve it any length of time, it is neceffary to moi-
ften it occafionally with urine. By a fimilar prepara¬
tion, other fpecies of lichen may be ufed in dyeing.
In this country the lichen omphalodes and tartareus me.
frequently employed for dyeing coarfe cloths.
172. Archil gives out its colouring matter to water, Propertie?.
ammonia, and alcohol. The infufion of archil is of a
crimfon colour, with a (hade of violet. The addition
of an acid converts it to a red colour. Fixed alkalies
only render it of a deeper (hade j becaufe its natural
colour has been already modified by the ammonia with
which it is combined in the preparation. Alum pro¬
duces in the folution of archil a dark-red precipitate ;
the fupernatant liquor is of a yellowifli red colour.
With folution of tin a reddifh precipitate is formed,
which fubfides (lowly ; and the liquor retains a (light
tinge of red. This infufion lofes its colour in a few
days if it be entirely excluded from the air. To cold
marble the aqueous infufion of archil communicates a
fine violet colour, or blue inclining to purple. The
affinity between the done and the colouring matter is
fo ftrong, that it refills the aftion of the air longer
than colours which it gives to other fubftances. The
colour thus communicated to marble, has remained for
tw7o years unchanged.
173. Archil is alfo foluble in alcohol. This tine-Singula?
ture is employed for making fpirit of wine thermome-chanSc*
ters. A lingular phenomenon was obferved by the
Abbe Nollet when the tinfture was excluded from the
air. In a few years it was entirely deprived of its co¬
lour. The contaft of air reftored the colour j but it
was again deftroyed when deprived of it.
174. Carthamus, or baftard faffron, a vegetable fub-Carthamus.
dance ufed in dyeing, is the flower of an annual plant
w’hich is cultivated in Spain, Egypt, and the Levant.
There are two varieties of this plant, the one with
larger, the other with fmaller leaves. The variety
with larger leaves is cultivated in Egypt.
17^. The method of preparing the dowsers of car-Prepara-
thamus in Egypt, as it is deferibed by Haffelquift, istIon-
the following. After being prefled between two (tones,
to fqueeze out the juice, they are walhed feveral times
with fait water, preffed between the hands, and fpread
out on mats in the open air, to dry. In the day time
they are covered, that they may not dry too faft with
the heat of the fun, but they are left expofed to the dew
of the night. When they are fuff.ciently dry, they are
put
Chap.
Properties.
Prepara¬
tion of
rouge.
I. DYE
Of Simple put up, and kept for fale, under the name oifaffranon.
Colours. Care fliould be taken afterwards, not to keep it in too
 v ' dry a place ; for unlefs it is a little moiit, its properties
are confiderably impaired. ,
176. Carthamus contains two colouring fubftances,
a yellow fubftance, which is foluble in water, and as it
is of no ufe, it is extrafled by the procefs mentioned
above, by fqueezing the flowers between {tones till no
more colour can be prefled out. The flowers become
reddiflr in this operation, and lofe nearly one half of
their weight. The other colouring matter, which is
red, is foluble in alkaline carbonates, and it is precipi¬
tated by means of an acid. A vegetable acid, as le¬
mon juice, has been found to produce the fineft colour.
Next to this, fulphuric acid produces the belt effect,
provided too great a quantity, which would alter and
deftroy the colour, be not employed. The juice of
the berries of the mountain afli, or rowan tree, (forbus
aucuparia, Lin.) is recommended by Scheffer as a fub-
flitute for lemon juice, and it is thus prepared. The
berries are bruifed in a mortar with a wooden peftle,
and the expreffed juice, after it has been allowed to
ferment, is bottled up. The clear part, which is moft
acid, becomes fitter for ufe the longer it is kept j but
this operation requires a period of fome months, and
can only be condufted in fummer.
177. From the colouring matter extra&ed by means
of an alkali, and precipitated with an acid, is procured
the fubftance called rouge, which is employed as a
paint for the Ikin. The folution of carthamus is pre¬
pared wuth cryftals of foda, and precipitated with le¬
mon juice which has flood fome days to fettle. After
being dried on delft plates with a gentle heat, the pre¬
cipitate is feparated, and ground accurately wuth talc
which has been previoufly reduced to a very fubtile
powder j and on the finenefs of the talc depends the
difference between the cheaper and dearer kinds of
rouge.
Brazil Brazil wood is of very extenfive ufe in dyeing.
wood. It is the wood of the csfalpinia crijla, Lin. and is a na¬
tive of America and the Weft Indies. It is known
under different names, according to the place wTere it
is produced •, as, Fernambouc, Bra%lletto, wood of St
Martha, and of Sapan. It is a very hard wood, and
has fo much denfity as to fink in water. When frefli
cut, it is of a pale colour, but becomes reddifh by ex-
pofure to the air, and it has a fweetifh tafte.
T 0 erties. I79* colouring matter of Brazil wood is folu¬
ble in water, and the whole of it may be extra&ed by
continuing the boiling for a fuflicient length of time.
The deco&ion is of a fine red colour. The refiduum,
which is black, yields a confiderable portion of colour¬
ing matter to alkalies. This colouring matter is alfo
foluble in alcohol, and in ammonia, and the colour is
deeper than that of the aqueous folution. The tinc¬
ture of Brazil wood in alcohol gives to hot marble a
red colour, which afterwards changes to violet. The
frefh deco£tion yields, with fulphuric acid, a fmall por¬
tion of a red precipitate, inclining to fawn colour.
Nitric acid firft produces a yellow colour, but by add¬
ing more, a deep orange. Oxalic acid produces a pre¬
cipitate of an orange red. Tartar furnifhes a fmall
precipitate: with the addition of fixed alkali, the decoc¬
tion becomes of a deep crimfon or violet colour. Am¬
monia gives a brighter purple j alum produces a copious
I N G. 4J9
red precipitate, inclining to crimfon. Sulphate of iron Of Simple
occafions a black colour in the tin&ure, with a copious, Col°uls- ,
precipitate of the fame colour. Sulphate of copper al¬
io produces an abundant precipitate, the liquor remain¬
ing tranfparent, and of a browniftt red. A copious
precipitate of a fine deep red, is produced with acetate
of lead, and that obtained with muriate of tin is abund¬
ant, and of a fine rofe colour. With the addition of
corrofive fublimate, a light precipitate, which is of a
brown colour, is obtained. The liquor remains tranf¬
parent, and of a fine yellow colour. Brazil wood
which has been changed to a yellow colour by means
of tartar and acetous acid, with a folution of nitro-mu-
riate of tin, yields a copious rofe-cploured precipitate j
and if to the folution, rendered yellow by an acid, a
greater quantity of the fame acid, or a rtronger acid,
as the fulphuric, be added, the red colour is reftored.
Some falls allb poflefs the property- of reftoring the red
colour of Brazil wood, which has been deftroyed by
means of acids *. The decoflion of Brazil wmod, * Jour, de
which is called juice of Brazil, is found to anfwer bet- ^byf-
ter for the procefles of dyeing, when it has been kept
fome time, and has even undergone fome degree of
fermentation, than when it has been freih prepared.
The colour, by keeping, becomes of a yellowifli red.
180. Logwood, fometimes called India or Cam-Logwood,
peachy wood, fhematoxylon Campeachianum, Lin.) is
a tree which grows to a confiderable fize in Jamaica,
and the eaftern fhore of the bay of Campeachy. Its
fpecific gravity is greater than that of water ; it has a
fine grain, and is fufceptible of a fine polifti. Log¬
wood yields its colouring matter, which is a fine red,
readily and copioufly to alcohol. It is more fparingly Propertie'.
foluble in water, and the decodlion inclines a little to
violet or purple. When it is left fome time to itfelf,
it becomes yellowilh, and at length black. It becomes
yellow alfo by the atlion of acids ; alkalies produce a
deeper colour, and convert it to a purple or violet.
Sulphuric, nitric, and muriatic acids form a fmall pro¬
portion of precipitate, which feparates {lowly : the
precipitate formed with fulphuric acid is of a dark red j
with muriatic, a lighter red, and wdth the nitric,
feuille mort. With fulphuric and muriatic acids,
the fupernatant liquor is of a deep red colour ; with
nitric it is yellowilh, and in all tranfparent. Ox¬
alic acid produces a precipitate of a light marone co¬
lour j the liquor remains tranfparent, and is yellowilh
red. Acetic acid produces a fimilar effedt, but the
colour of the precipitate is fomewhat deeper. A fimi¬
lar precipitate is obtained by means of tartar j but the
liquor, which is more inclined to yellow', remains tur¬
bid. No precipitate is produced by means of fixed al¬
kali j the decodlion becomes of a deep violet, which
is afterwards converted to a brown colour. Alum
yields a copious precipitate, of a lightilh violet colour j
the colour of the liquor remains the fame, and it is
nearly tranfparent. A copious, dark red precipitate is
produced with alum and tartar ; the liquor is yellow'ilh
,red and tranfparent. Sulphate of iron occafions a
bluilh black colour ; a copious, precipitate of the fame
colour is formed, and the liquor remains long turbid.
With fulphate of copper, a very copious precipitate, of
a deep brown colour, is obtained 5 the liquor, which is
alfo of a deep brown, or yellowilh red, remains tranf¬
parent. Acetate of lead yields a black precipitate,
3 G 2 with
420 DYE
Of Simple ■with a flight tinge of red ; the colour of the liquor is
, Colours. < jjj,e thgt Gf pa|e beej-^ ancl it remains tranfparent.
Nitro-muriate of tin gives a precipitate of a fine violet
or purple colour j the liquor remains clear and colour-
lefs.
» 2. Of the Proeejfes for Dyeing Wool Red.
181. All red colouring matters with which we are
acquainted, come under that clafs of colours to which
Dr Bancroft has given the name of adjeElive colours ;
that is, fuch colours as require the aid of mordants to
render them permanent. Red colours, we have al¬
ready obferved, are of various (hades, according to
the nature and proportion of the colouring matters em¬
ployed. Hence we have madder red, fcarlet, crimfon,
and other (hades.
Madder 182. Madder Red.—Madder is only employed for
red. dyeing coarfe woollen fluffs, and the following is the
procefs. The fluffs are firft boiled for two or three
hours with alum and tartar •, they are then left to
drain, (lightly wrung out, put into a linen bag, and
carried into a cool place, where they are to remain for
fome days. The quantities and proportions of the alum
and tartar are varied according to the view’s of the
dyer, and the (hade of colour which is wanted. Some
recommend five ounces of alum and one ounce of tartar
to each pound of wool. By increafing the proportion
of tartar to a certain degree, a deep and permanent
cinnamon colour, inftead of a red, is produced. This
arifes from the yellow tinge which is induced by means
of the acid on the colouring particles of the madder.
Proeefs. Others propoie to diminifh the proportion of tartar,
and to employ only a feventh part. In conducing
the procefs of dyeing with madder, thp bath (hould
not be brought to the boiling point, becaufe at that
temperature the fawn-coloured particles w’ould be dif-
folved, and a different (hade obtained from that which
is defired. When the water is at that degree of tem¬
perature which the hand can bear, Hellot recommends
the addition of half a pound of grape madder for every
pound of wool to be dyed. It is then to be well ftir-
red before the wool is introduced, which muft remain
for an hour wdthout boiling, excepting for a few mi¬
nutes towards the end of the procefs, that the combi¬
nation of the colouring particles with the fluff may be
more certain.
Rofnig. 183. Madder reds are fometimes rofed, as it is call¬
ed, with archil and Brazil wood. In this way they
become more beautiful and velvety, but this bright-
nefs is not permanent. But madder reds, even when
they are moft perfeft, are far inferior to thofe obtained
from lac and cochineal, and even to that produced by
kermes 5 but as the expence of the materials is com¬
paratively fmall, they are employed, as we have already
obferved, for coarfe fluffs.
„ - 184.. Different authors recommend different propor-
Proportion . t c . 1 ‘
of madder, tions of madder. Poerner propotes to employ one-
third of the weight of the wool, while Scheffer limits
the quantity to one-fourth. In one procefs, Poernef
added to the alum and tartar, a quantity of folution of
tin, equal in weight to the tartar, and after two hours
boiling, allowed the cloth to remain in the bath,
which had been left to cool for three or four days. He
then dyed it in the ufual way, and thus obtained a fine
red. According to another procefs, he prepared the
1 N G. Part II.
cloth by the common boiling, and dyed it in a bath Of Simple
(lightly heated, with a larger proportion of madder, Colours,
tartar, and folution of tin. The cloth remained 24 ‘—-'V—
hours in the bath, and when it had become cold, he put
it into another bath, made with madder only, where
it remained for 24 hours. By this procefs he got a
fine red, fomewhat brighter than the common, but in¬
clining a little to yellow. Scheffer informs us that he
obtained an orange red by boiling wool with a folu¬
tion of tin, and one-fourth of alum, and then by dye¬
ing with one-fourth of madder. A cherry colour is
obtained, according to Bergman, by dyeing with one
part of a folution of tin, and two of madder, without
previoufly boiling the wool. By expofure to the air,
this colour becomes deeper. By boiling the wool for
two hours with one-fourth of fulphate of iron, then
waflung it, and afterwards immerfing it in cold w’ater
with one-fourth of madder, and 'then boiling for an
hour, the refult is a coffee colour. But if the wmol
has not been forked, and if it be dyed with one part
of fulphate of iron and two of madder, the colour is a
brown approaching to red.
185. When fulphate of copper is employed as the Different
mordant, the madder dye yields a clear brown, in-raordants.
dining fomewhat to yellow ; and a fimilar colour may
be produced by dyeing the wool (imply foaked in hot
water, with one part of fulphate of copper, and two of
madder. But W'hen this mordant and dye-fluff are
ufed in equal proportions, the yellow is fomewhat
more obfeure, approaching to green; and in both thefe
inftances, expofure to the air does not produce a dark¬
er colour. Berthollet informs us that he employed a
folution of tin in vaiious ways, both in the preparation
and in the application of the madder , and by the ufe
of different folutions of tin, he found, that although
the tint was fomewhat brighter than what is obtained
by the common procefs, it was always more inclined
to yellow or fawm colour.
186. Scarlet.—The fineft and moft fplendid of all Scarlet,
colours is fcarlet. This, like other colours, is of va¬
rious (hades, according to the quality and proportion
of the colouring matter employed. The fcarlet dye is
communicated to woollen fluffs by means of cochineal,
the hiftory and properties of which we have already
detailed. The Mexicans, as appears from their hB
ftory, employed alumina as the bafis or mordant, to
fix the colour of cochineal ; and previous to the dif-
covery of the folution of tin, the ufe of the fame fub-
ftance feems to have prevailed in Europe. The fine
colour obtained from the latter, received, as we have
already mentioned, different names in different places ;
as that of bow dye in England, fcarlet of the Gobelins
in France, and in Holland Dutch fcarlet.
187. In the procefs for dyeing fcarlet, two opera-Procefs.
tions are neceffary. The firft is denominated the boil¬
ing, and the fecond is diftinguifhed by the name of fi-
nilhing or reddening. The operation of boiling, which Boiling,
is the firft part of the procefs, is conduced in the fol¬
lowing manner. For 100 pounds of cloth, 6 pounds
of pure tartar are added to the water, which is made
pretty warm. The bath is then to be brilkly flirred,
and when the heat has increafed a little more, half a
pound of powdered cochineal is to be added, and the
whole is then to be well mixed. The next moment
five pounds of a very clear folution of tin are to be
poured
Chap.
Of Simple
Colours.
Reddening.
Proportion
of ingre¬
dients.
Shorter
procefs.
Brighter
red.
D Y E I
poured in, and carefully mixed. When the bath be- pears
gins to boil, the cloth is introduced, and brilkly mo¬
ved for two or three turns 5 after which it is moved
more {lowly. The boiling having continued for two
hours, the cloth is taken out, expofed to the air, and
carried to the river to be well wadied.
188. In the preparation of the fecond bath, which
is for the reddening, the boiler is to be emptied, and
when the bath has juft reached the boiling point,
five pounds and three quarters of cochineal, previouf-
ly powdered and lifted, are to be added. Thefe are
to be .carefully mixed; and after having ceafed ftirring,
when a cruft has formed on the furface, and opened of
itfelf in feveral places, 13 or 14 pounds of folution of
tin are poured in. Should the bath, during the boil¬
ing, rife above the edge of the boiler, it may be cool¬
ed with a little cold water. This folution being well
mixed, the cloth is put in, and two or three times
quickly turned. It is then boiled in the bath for an
hour, taking care to keep it under the furface. It is
afterwards taken out, expofed to the air, and when it
has cooled, waftied in the river and dried.
189. There are no determinate proportions of cochi¬
neal and folution of tin in either of thefe operations.
Hellot informs us, that fome dyers employ two-thirds
of folution of tin, and one-fourth of cochineal, in
the boiling or firft operation, and the other one-third
of the folution of tin with the remaining three-fourths
of the cochineal in the fecond operation, or the red¬
dening. He adds farther, that the ufe of tartar gives
a greater degree of permanency to the colour, provi¬
ded the proportion do not exceed one-half the weight
of the cochineal employed. According to Berthollet,
feveral dyers at prefent adopt this practice. Tartar,
he obferves, promotes the folution of the colouring
matter, and this effeft is greater when it is ground
with the cochineal, after which it is found that the re-
fiduum is more completely exhaufted. But this con-
fideration is of inferior confequence, when the opera¬
tions are fucceftively performed, becaufe any colouring
matter that may remain in the refiduum, is employed
in the next operation. It ought not, however, to be
overlooked, that the tartar communicates to the co¬
lour a rofey hue.
190. It is the practice of fome dyers not to remove
the cloth out of the boiling. They merely refrefh it,
and perform the operation of reddening in the fame
bath. When this is done, the infufion of cochineal,
made in a feparate veffel, and mixed with the proper
proportion of folution of tin, is added. By conduc¬
ing the procefs in this way the fcarlet is fuppofed to be
equally fine, and there is a confiderable faving of time
and fuel.
191. To give fcarlet the bright lively red which,
as it approaches to the colour of fire, has been diftin-
guiftied by the name of fiery fcdrlet, a yellow tinge is
communicated by boiling fuftic in the firft bath, or by
adding a little turmeric to the cochineal. A larger
proportion of the folution of tin alfo produces this
yellow' {hade, but it renders the cloth harfti, and li¬
mits the aftion of the colouring matter. The ufe of
fuftic or turmeric, therefore, although the colour ob¬
tained from them is not permanent, is preferable to an
excefs of the folution of tin. When thefe fubftances
are ufed, the infide of the-cloth, when it is cut* ap-
N G. 421
yellow ; but in the ordinary procefies, the co- Of Simple
Colours.
chineal, it is found, does not penetrate the cloth, for, 
when no other fubftance is employed, the cloth is in¬
ternally white.
192. The ufe of tin boilers is recommended in dye-Tin atKl
ing fcarlet. When copper boilers are employed, the^?^
acid a&s on the metal, and thus forming a folution,
injures the beauty of the colour. I in boilers, how¬
ever, are attended with feveral inconveniences. It is
difficult to procure them of fufficient fize, and they
are apt to be melted by the incautious continuance of
the fire, after they have been emptied. In the ufe of
copper boilers, there are feveral neceffary precautions.
They muft be kept very clean ; the acid liquor ftiould
not be allowed to remain in them for any length of
time, and fome contrivance fhould be adopted to pre¬
vent the cloth from touching the metal, either by u-
fing a net, or a wucker balket.
193. Different proportions of materials, we havre Different
obferved, are recommended by different authors. ForF0.^0”1®13
the boiling, Scheffer dire&s an ounce and a half of^J”^6"
folution of tin, with an equal quantity of ftarch, and
as much tartar, to every pound of cloth. I he effeft
of the ftarch is to give more uniformity to the colour.
When the water boils, a dram of cochineal is to be
added ; it is then to be well ftirred, and after the
wool is introduced, to be boiled an hour, taken out,
and waftied. The proportions for the reddening bath,
in which the wool is to be boiled half an hour, are
half an ounce of ftarch, three-fourths of an ounce of
folution of tin, half an ounce of tartar, and 7 drams
of cochineal. In Scheffer’s procefs, it may be obferved,
the proportion of folution of tin is fmaller than in that
of Hellot, but the quantity of tin in the folution of
the former is greater than in that of the latter.
194. Poerner has defcribed three principal proceftes, Poerner’s
according to the variety of the fliade of the fcarlet.P10Ce s‘
He ufes no cochineal in the boiling ; the materials
of which are one ounce and fix drams of tartar, and
an equal weight of folution of tin, the latter being
added after the tartar is diffolved, for every pound of
cloth. As foon as the boiling has commenced, the
cloth is introduced, and it is boiled for two hours.
For the reddening of the firft procefs he employs two
drams of tartar and one ounce of cochineal, adding
gradually afterwards two ounces of folution of tin.
For the reddening of the fecond procefs, the fame
quantity of cochineal and folution of tin, without
any tartar, is employed. In the reddening of the
third procefs, two drams of tartar, with one ounce of
folution of tin, one ounce of cochineal, and two ounces
of common fait, are directed to be ufed. The co¬
lour produced in the firft procefs has the deepeft
{hade ; that of the fecond is more lively, while that
of the third is paler and brighter.
195. By the ufe of tartar in the reddening in diffe-Different
rent proportions, various (hades of fcarlet may be ob-(hades,
tained. When it is employed, the ftiade is deeper and
fuller, but when it is entirely omitted, the fcarlet ap¬
proaches to an orange colour. The lhade of colour
alfo is fubjeft to confiderable variety, from the diffe¬
rent degrees of ftrength of the folution of tin. To
afeertain this effedt, Berthollet made a number of ex¬
periments. He found that a iblution of tin compofed
of^Rxteen parts of nitric acid, two of muriate of am-
monia9
422 DYE
Of Simple tnonla, and three of tin, produced a deeper lhade than
, (~'Q^0Ulb' when the proportions of the acid and muriate of am¬
monia were equal, with only two parts of tin. The laft
proportions, he obferves, fucceeded beft. Four parts of
water were mixed with the folution. When the propor¬
tion of muriate of ammonia amounted only to halt a part,
the colour was brighter, and inclining to orange.
Uieofcom- 196. Common fait has the effeft of increafing the
lllon la^’ brightnefs of fcarlet, while it is alfo attended with
the advantage of caufing the colour to penetrate deep¬
er into the cloth. It feems difficult to explain why
common fait, which gives a deeper lhade to the co¬
lour of the infulion of cochineal, and indeed produces
a limilar effedl on colours in general, fiiould diminilh
the intenlity of the colour of fcarlet. The proportion
of common fait mentioned above (194) is, according
to Poerner, the greateft that can be employed. When
lefs is ufed, the lhade, though lighter, is more agree¬
able. By adding five ounces of white fugar to the
ingredients of the fecond procefs, a finer colour, which
is always lighter than that of the firll procefs, will be
obtained. The colour, it is faid, is more permanent,
and the (hade more agreeable, when the cloth is left
24 hours in the boiler after it has cooled.
Procefs of I97" It has been generally fuppofed, Dr Bancroft
dyeing obferves, that after the difcovery of the efFe«5ts of tin
fcarlet with on the cochineal colour, to produce a fcarlet, it was
cochineal only neceffary to apply the colour fo produced as a
dye to wool ; or that a nitric or nitro-muriatic fo¬
lution of tin might change the natural crimfon of
cochineal to a fcarlet. This opinion, however, he
-confiders to be quite erroneous; for the nitric folu¬
tion of tin invariably produces with cochineal a crim¬
fon or rofe colour, and not a fcarlet, unlefs other
means are employed to incline the cochineal colour to
a yellow- {hade. This effeft is produced by means of
the tartar, which feems to have been accidentally Hum¬
bled upon, and has been for many ages ufed, without
knowing its true effeft. Tartar was long employed
with the aluminous mordant, in the preparation of the
ordinary boiling liquor for woollen cloths $ and it is
probable that its good effects being obferved in this
combination, the ul of it was continued after the in-
troduftion of the folu-.on of tin j and the more fo, af¬
ter the refiilt of the combination was obferved in the
brilliancy of the colour which was produced. Dr
Bancroft has particularly direfled his attention to the
procefs for dyeing fcarlet ; and in the progrefs of his
inveftigations, he has found that it is by no means ab-
folutcly neceffary to follow the ufual procefs which we
have defcribed above. Fie has often, he fays, pro¬
duced that colour very well at a fingle boiling, by
mixing the whole quantity of tartar, folution of tin,
and cochineal together j the affinity of the ^’ool for
the colouring matter, and for the oxide of tin, being
fufficiently ftrong to combine with them readily, and
to retain them permanently. The only objedh’on to
fimplifying the procefs in this manner is, that the co¬
louring matter of the dyeing liquor is lefs perfe£lly ex-
haufted than when two operations are performed. Fie
farther adds, that he has often produced a beautiful
fcarlet, by preparing and boiling the cloth with the
whole quantity of folution of tin and tartar at once,
and afterwards dyeing it unrinfed, with the w hole of
lhe cochineal, diffolved only in pure water. In this
I N G.
Pan If,
way he found the colouring particles completely taken Of Simple
up } that the liquor had become quite colourlefs, and Co ours,
that the cloth had received a durable dye. y
198 “ It is remarkable,” fays Dr Bancroft, “ that
during the 18th century, no confiderable improvementtl0nar^*
has been made in the procefs for dyeing fcarlet ; a cir-
cumftance which is the more extraordinary, fince the
pre-eminent luftre and coftly nature of this dye, have
rendered it an objeft of particular attention, not only
to dyers, but to eminent chemilts, by whofe refearches
W’e might have expedled that at leaf! every obvious im¬
provement therein would have been long fince attain¬
ed.” To attain this objefl, this ingenious philofopher
inftituted a fet of experiments, about the year 1786.
Flaving, by repeated affufions of boiling water, extraft-Dr Baa¬
ed the whole of the colouring matter frojn powdered crofCs ex'
cochineal, he found that the addition of a little potafii l)eunients*
to the feemingly exhaufled fediment, and a freffi quan¬
tity of boiling water, extrafted a new portion of co¬
louring matter, equal to about one-eighth of what had
been given out to the pure water. He repeatedly ex-
traiffed this colouring matter by means of potaffi, and
afterwards dyed fmall pieces of cloth fcarlet with it,
which he found fimilar to other pieces dyed with the
more foluble colouring matter of cochineal. It was in
the courfe of thefe inquiries that he perceived fcarlet to
be a compound colour, confifting of about three-fourths
of pure crimfon or rofe colour, and one-fourth of
pure bright yellow’. He conceived, therefore, that Scarlet a
when the natural crimfon of the cochineal is made compound
fcarlet, by the ufual procefs, there muff be a change C0i0ur-
produced, equivalent to a converfion of one-fourth of
the colouring matter of cochineal born its natural
ciimfon to a yellow colour. From this he concludes
that there might be a great faving of cochineal, by fub-
ftitutingacheaper fubftance, which at the fame time might
yield a better yellow colour. It was therefore his ob¬
ject to combine with this crimfon or rofe colour, a fuit-
able portion of a lively golden yellow’, capable of be¬
ing permanently fixed, and refie&ed by the fame bafis.
Such a yellow he had difeovered in quercitron bark,
(quercus nigra, Lin.) which will be afterwards de¬
fcribed; and it had the advantage, not only of being
the brighteft, but alfo the cheapeft of all the yellows,
which he had tried.
199. With the view of diminiffiing the quantity of
cochineal employed, in producing a fcarlet dye, Dr
Bancroft made a number of experiments under the au¬
thority of government. In thefe experiments, the
mordant ufed was the ordinary dyers fpirit, or the ni-
tro-muriate of tin ; but he found that they w’ere not
attended with the advantages which he expected. In
fome of his earlieft experiments, he obferves, that the
folution of tin by means of fulphuric acid deftroyed
the cochineal colour; and this naturally led him to re¬
ject-the ufe of this acid, till accident brought him to
diffolve a quantity of tin in muriatic acid, combined
with one-fourth of fulphuric acid. The application of
this folution in dyeing, was not accompanied with the
corrofive effects of the muriate and nitro-muriate which
he had employed in the experiments above alluded to,
and which proved unfuccefstul. After trying different
proportions of thefe acids, he found the following to
anfwer beft. In a mixture of albs, of fulphuric acid
of the ordinary ftrengtb, and about 3lbs. of muriatic
acid,
Chap. I.
Of Simple acid, he dilTolved about 14 oz. of tin. The muriatic
Colours. acid is firft poured on a large quantity of granulated
      t;n a large glafs receiver, and the fulphuncacidis then
flowly added. The folution is more raptdly promoted
by means of a fand heat, but it will take place m the
cold, requiring only a greater length of time.
This murio-fulphate of tin is Jranfparent and colour-
lefs, and may be kept for feveral years without any
precipitation. It produces twice the effett of the
dyers fpirit, at lefs than one-third of the expence, and
raifes the colours not only more than the dyers fpirit,
but alfo full as much as the tartrate of tin, without
converting the crimfon of cochineal to a yellowilh
Dr Ban- ^200. In the ufe of this folution of tin as a mordant,
croft’s pro- to produce the compound fcarlet colour with t re co-
cers- chineal crimfon and quercitron yellow, Dr Bancroft
recommends the following procefs. “ Nothing,” fays
he, “ is neceffary but to put the cloth, fuppofe lOOlb.
weight, into a proper tin veffel, nearly filled, wuth
water, in which about eight pounds of the muno-ful-
phuric folution of tin have been previoufly mixed, to
make the liquor boil, turning the cloth as ufual through
it bv the winch, for a quarter of an hour ; then turn¬
ing the cloth out of the liquor, to put into it about
four pounds of cochineal, and two pounds and a halt
of quercitron bark in powder, and having mixed
them well, to return the cloth again into the liquor,
making it boil, and continue the operation as ulual
until the colour be duly raifed, and the dyeing liquor
exhaufted, which will be the caie in about fifteen or
twenty minutes •, after which the cloth may be taken
out and rinfed as ufual. In this way the time, labour,
and fuel, necedhry for filling and heating the dyeing
veffel a fecond time, wall be faved ; the operation
finifhed much more fpeedily than in the common way;
and there will be a faving of all the tartar, as well as
of two-thirds of the coft of fpirit, or nitro-muriatic fil¬
iation of tin, which for dyeing xoolb. of wool, com¬
monly amounts to 10s ; whereas, 81b. of the muno-
fulphuric folution will only coft about 3s. There will
be moreover a faving of at leaft one-fourth of the co¬
chineal ufually employed, (which is generally comput¬
ed at the rate of one ounce for every pound of cloth,)
and the colour produced will certainly not prove in¬
ferior in any refpefl to that dyed with much more ex¬
pence and trouble in the ordinary way. When a rofe-
colour is wanted, it may be readily and cheaply dyed
In this way, only omitting the quercitron bark, in-
ftead of the complex method now pra&ifed of firft pro¬
ducing a fcarlet, and then changing it to a rofe by the
volatile alkali contained in ftale urine, fet free or de-
fcompofed by potalh or by lime : and even if any one
ftiould ftill unwifely choofe to continue the praftice of
dyeing fcarlet without quercitron bar»c, he need only
employ the ufual proportions of tartar and cochineal, Of Simple
with a fuitable quantity of the muno-fulphate of tin,
which, whilft it cofts fo much lefs, will be more effec¬
tual than the dyers fpirit. . „ . .
201 “ Several hundreds of experiments warrant my Saving of
affertion, that at leaft a fourth part of the cochineal cochineal,
generally employed in dyeing fcarlet, may be faved by
obtaining fo much yellow as is neceffary to compoie
this colour from the quercitron bark ; and indeed no¬
thing can be more felf-evident, than that fuch an ef-
fe£l, ceteris paribus, ought neceffarily to relult from
this combination of different colouring matters, fuite<I
to produce the compound colour in queftion. Let it
be recolle&ed that the cochineal crimfon, though ca¬
pable of being changed by tartar towards the yellow
hue on one hand, is alfo capable by other means of be-
ino- changed towards a blue on the other, and ofthere-
bjT producing a purple without indigo or any other
blue colouring matter: yet I am confident that nobody
would believe a pound of cochineal fo employed capa¬
ble alone of dyeing as much cloth,, of any particular
{hade of purple, as might be dyed with it, if the whole
of its colouring matter were employed folely in furmfti-
iug the crimfon part of the purple, whilft the other
(blue) part thereof was obtained from indigo. 'I o
lay that a pound of cochineal alone could produce as
much effedl or colour as a pound of cochineal
and a pound of indigo together, would be an im¬
probability much too obvious and palpable for hu
man belief; and there certainly would be a fimilar
improbability in alleging, that a pound of cochineal,
employed in giving another compound colour (fcarlet),.
could alone produce as much effeft as a pound of co¬
chineal and a pound of quercitron bark, when the co¬
lour of this laft was employed only in furniihing one
of the component parts of the fcarlet, for which a con-
fiderable portion of the colouring matter of the cochi¬
neal muft otherwife have been expended, which cer¬
tainly happens in the new mode of dyeing fcarlet, be-
caufe the colour produced with an addition of the
quercitron yellow inclines no more towards a yellow,
than the fcarlet produced by yellowing.a part of the
cochineal colour in the ufual method with taitar. I
retain, therefore, at this moment, as much confidence
as I ever had in the reality and importance of my pro-
pofed improvements in this refpedl (h.)
202 “ The fcarlet compofed of cochineal crimfon Advanta-
and quercitron yellow, is moreover attended with this
advantage, that it may be dyed upon wool and wool¬
len yarn without any danger of its being changed to a
rofe or crimfon, by the procefs of fulling, as ^always
happens to fcarlet dyed by the ufual means. This laft
being in faft nothing but a crimfon or role colour, yel¬
lowed by fome particular a&ion or effeft of the tartar,
is liable to be made crimfon again by the application of
many
chineal
time
P„“ r/h'S Si;‘Xr S has ‘been boiled *4 «be fo,ution of tl„,
^ r?oc.'hatur,ru«h «r'“cnx ^ ^^
ufual way of employing that drug.”
4H DYE
Of Simple many chemical agents, (which readily overcome the
Colours, changeable yellow produced by the tartar,) and parti¬
cularly by calcareous earths, foap, alkaline falls, &c.
But where the cochineal colouring matter is applied
and fixed merely as a crimfon or rofe colour, and is
rendered fcarlet by fuperadding a very permanent
quercitron yellow, capable of refilling the ftrongelt
acids and alkalies, (which it does when dyed with fo-
lutions of tin,) no fuch change can take place, becaufe
the cochineal colour having never ceafed to be crimfon,
cannot be rendered more fo, and therefore cannot fuf-
fer by thofe impreffions or applications which frequent¬
ly change or fpot fcarlet dyed according to the prefent
praflice.”
203. “ There is alfo a lingular property attending
li ht on t^le comPound fcarlet dyed with cochineal and quer-
this fcarlet citron bark •, which is, that if it be compared with
dye. another piece of fcarlet dyed in the ufual w'ay, and
both appear by day-light exactly of the fame fiiade,
the former, if they be afterwards compared by candle¬
light, will appear to be at leall feveral lhades higher
and fuller than the latter ; a circumllance of fome im¬
portance, when it is confidered how much this and
other gay colours are generally worn and exhibited
by candle-light during a confiderable part of the
year.”
Effedt of
candle
Effedts of 204. “ To illullrate more clearly the effefts of the
murio-ful- murio-fulphuric folution of tin with cochineal in dye-
Futionof' ftate a very few °f my numerous ex-
-tin. periments therewith *, obferving, however, that they
were all feveral times repeated, and always with fimi-
lar eflfedls.
“ ill, 1 boiled one hundred paits of woollen cloth in
water, with eight parts of the murio-fulphuric folution
of tin, during the fpace of ten or fifteen minutes •, I
then added to the fame w ater four parts of cochineal,
and two parts and a half of quercitron bark in powder,
and boiled the cloth fifteen or tw’enty minutes longer ;
at the end of which it had nearly imbibed all the co¬
lour of the dyeing liquor, and received a very good,
even, and bright fcarlet. Similar cloth dyed of that
colour at the fame time in the ufual wray, and with a
fourth part more of cochineal, was found upon com-
parifon to have fomewhat lefs body than the former j
the effect of the quercitron bark in the firll cafe hav¬
ing been more than equal to the additional portion of
cochineal employed in the latter, and made yellow by
the aftion of tartar.”
“ 2d, To fee whether the tartrite of tin would, befides
yellowing the cochineal crimfon, contribute to raife
and exalt its colour more than the murio-fulphate of
that metal, I boiled one hundred parts of cloth with
eight parts of the murio-fulphuric folution, and fix
parts of tartar, for the fpace of one hour 5 I then dyed
the cloth, unrinfed, in clean water, with four parts of
cochineal, and tw’O parts and a half of quercitron bark,
which produced a bright aurora colour, becaufe a
double portion of yellow had been here produced, firft
by the quercitron bark, and then by the action of
tartar upon the cochineal colouring matter. To bring
back this aurora to the fcarlet colour, by taking away
or changing the yellow produced by the tartar, I di¬
vided the cloth whilll unrinfed into three equal parts,
and boiled one of them a few minutes in water flightly
imprfegnated with potalh j another in water with a lit-
2
I N G. - Part H.
tie ammoniac*, and the third in water containing a very Of Simple
little powdered chalk, by which all the pieces became Colours,
fcarlet j but the tw*o laft appeared fomewhat brighter'
than the firlt, the ammoniac and chalk having each
rofed the cochineal colour rather more advantageoufly
than the potalh. The bed of thefe, however, by
comparifon, did not feem preferable to the com¬
pound fcarlet dyed without tartar, as in the preceding
experiment; confequently this did not feem to exalt
the cochineal colour more than the murio-fulphate of
tin ; had it done fo, the ufe of it in this way would
have been eafy, without relinquilhing the advantages of
the quercitron yellow*.”
“ 3d, I boiled one hundred parts of woollen cloth
with eight parts of the murio-fulphuric folution of tin,
for about ten minutes, when I added four parts of co¬
chineal in powder, which by ten or fifteen minutes
more of boiling, produced a fine crimfon. This 1
divided into two equal parts, one of which I yellowed
or made fcarlet by boiling it for fifteen minutes with a
tenth of its weight of tartar in clean water ; and the
other, by boiling it with a fortieth of its weight of
quercitron bark, and the fame weight of murio-ful¬
phuric folution of tin ; fo that in this lall cafe there
was an addition of yellow colouring matter from the
bark, whilft in the former no fuch addition took place,
the yellow* neceffary for producing the fcarlet having
been wholly gained by a change and diminution of
the cochineal crimfon j and the two pieces being com¬
pared with each other, that which had been rendered
fcarlet by an addition of quercitron yellow*, was, as
might have been expedled, feveral lhades fuller than
the other.”
“ 4th, I dyed one hundred parts of w*oollen cloth
fcarlet, by boiling it firll in water w*ith eight parts of
murio-fulphate of tin, and twelve parts of tartar, for
ten minutes, and then adding five parts of cochineal,
and continuing the boiling for fifteen minutes. This
fcarlet cloth I divided equally, and made one part
crimfon, by boiling it with a little ammoniac in clean
water j after which I again rendered it fcarlet, by
boiling it in clean water, with a fortieth of its w*eight
of quercitron bark, and the fame w*eight of murio-
fulphate of tin \ and this lall, being compared with
the other half, to which no quercitron yellow had
been applied, was found to poffefs much more colour,
as might have been expefled. A piece of the cloth,
w*hich had been dyed fcarlet by cochineal and quer¬
citron bark, as in the firll experiment, being at the
fame time boiled in the fame water with ammoniac,
did not become crimfon, like that dyed fcarlet with¬
out the bark.
205. “ In this way of compounding a fcarlet from
cochineal and quercitron bark, the dyer will at all
times be able, with the utmoll certainty, to produce
every pofiible lhade between the crimfon and yellow
colours, by only increaling or diminilhing the propor¬
tion of bark. It has indeed been ufual at times, when
fcarlets approaching nearly to the aurora colour were
in falhion, to fuperadd a fugitive yellow either from
turmeric, or from what is called young fullic (Rhus
Cotinuj) *, but this was only when the cochineal co¬
lour had been previoufly yellowed as much as poflible
by the ufe of tartar, as in the common way of dyeing
fcarlet; and therefore that pra&ice ought not to be
confounded
Chap.
Colours,
.1. DYE
Of Simple confounded with my improvement, which has for its
gbjefl to preclude the lofs of any part of the cochi.
neal crimfon, by its converfion towards yellow colour,
which may be fo much more cheaply obtained than the
quercitron bark. By fufficient trials, I have fatisfied
myfelf that the cochineal colours, dyed with the mu-
rio-fulphuric folution of tin, are in every refpeft at
leaft as durable as any which can be dyed with any
other preparation of that metal; and they even feem
to withftand the a£Hon of boiling foap fuds fomewhat
longer, and therefore I cannot avoid earneftly recom¬
mending its ufe for dyeing role and other cochineal co¬
lours, as well as for compounding a fcarlet with the
quercitron bark.”
206. Dr Bancroft afterwards tried a great variety
of earthy and metallic falts, as mordants, for the pur-
pofe of fixing the colour of cochineal on wool; and he
found that, befides the metallic oxides and folutions,
the aluminous, calcareous and filiceous earths, as well
as magnefia and barytes, might be employed with dif¬
ferent fuccefs in dyeing with the colouring matter of
cochineal : but for the detail of thefe experiments
which he has given, we refer our readers to the trea-
tife itfelf*.
207. To produce different (hades of fcarlet, and the
other colours wdiich are derived from it, all that is ne-
ceffary, is to vary the proportions of cochineal, tartar,
and folution of tin j and for the {hades which incline
moll to yellow, the addition of quercitron bark, or
fuftic, is requTTite. The ufe of the tartar is to deepen
the colour, and the folution of tin produces a (hade of
orange. When the (hade of colour required to be
communicated to the fluff is light, the time of con-
f tinning the procefs muff be {hortened f.
* Phil, of
Perm. Col.
SCO.
■Different
fhades of
fcarlet.
n. 194.
Crimfon
^lyed by
xme-procefs,
•or by the
converfion
of fcarlet.
20 8. Cr ini fori.—The proceffes which are employed
to dye wool a crinvfom colour, are two. The fluff is
either dyed crimfon at once, or the crimfon {hade is
communicated to it, after being previoully dyed of a
fcarlet colour. To dye crimfon by a lingle procefs,
a folution of two ounces and a half of alum, and an
ounce and a half of tartar for every pound of (luff,
is employed for the boiling, and the Huff is afterwards
to be dyed with an ounce of cochineal. It is ufual
alfo to employ folution of tin, but in fmaller propor¬
tion than for dyeing fcarlet. The proceffes employed,
it is fcarcely necelfary to obferve, mull vary, accord¬
ing as the lhade wanted is deeper or lighter, or more
or lefs dillant from fcarlet. Common fait is alfo em¬
ployed by fome in the boiling. To render the crim¬
fon deeper, and to give it more bloom, archil and po-
tafh are frequently ufied j but this bloom, it ought to
be obferved, is extremely fugacious. By adding tar¬
tar and alum, the boiling for crimfon is fometimes pre¬
pared after a fcarlet reddening, and it is faid that the
colour poffeffes more bloom, when both the boiling and
reddening are made after fcarlet, than when the crim¬
fon is dyed in a frefh bath prepared on purpofe. In
dyeing thefe colours, the wild cochineal may be em¬
ployed, but as it contains a fmaller proportion of co¬
louring matter, the quantity mull be greater.
209. Different fubllances, as the alkalies, alum, and
earthy falts in general, convert the colour of fcarlet
to crimfon, which is the natural colour of cochineal.
To effect this, the fluff previoully dyed fcarlet is boiled
for an hour in a folution of alum, the ftrength of which
Vol. VII. Part II.
I N G.
is to be regulated by the depth of fhade required. Of Simple
In condufting this procefs, it is neceffary to obferve, , Col°ur$- .
that water impregnated with earthy falts has a conli-
derable effha in varying the lhade j fo that the quan¬
tity of alum employed mull be proportioned to the
purity of the water. Hellot tried foap, foda, potalh,
and fome other fubllances, and although they produ¬
ced the crimfon, yet it was of a deeper lhade, and had
lefs lultre, than what was produced by means of alum.
Ammonia produced a good effe£t j but from its great
volatility, a confiderable proportion mull be put into
the bath, moderately heated, with a little fal ammo¬
niac, and an equal quantity of potalh. By this pro¬
cefs the Huff became of a bright rofy colour, and thus
rendered a fmaller quantity of cochineal neceffary.
Poerner dirc&s thei Huff previoufly dyed fcarlet, to re¬
main 24 hours in a cold folution of fal ammoniac and
potalh.
210. To produce crimfons, as wTell as fcarlets, in Half-grain
half grain, madder is to be fubllituted for half the crimlon»
quantity of the cochineal j or in other proportions, ac- c-
cording to the lhade defired. The fame boiling is
given as for fcarlet in grain, and the other parts of the
procefs are to be conduced as for reddening the fcar¬
let or crimfon. Even the common madder red affumes
a greater degree of lutlre, when the boiling is made ..
after a reddening for fcarlet 4i. ' U*
3. Of the ProceJJes for dyeing Si/k Red.
2\\. Madder red.—The colour which is obtained Different
from madder does not ppffefs fufficient brightnefs for
dyeing filk. We lhall here, however, deferibe fomeder,
of the proceffes which are employed for this purpofe.
That of De la Folie, is the following. Half a pound
of alum is to be diffolved in each quart of hot water,
and two ounces of potalh are afterwards to be added.
When the effervefcence has ceafed, and the liquor has
become clear, the filk mud be kept in it for two hours,
after which it is to be waflied, and put into the mad¬
der bath. The filk which is dyed in this way be¬
comes more beautiful by means of the foap proof.
The procefs of Scheffer is fomewhat different. For
each pound of fcoured filk, he direfls a folution of
four ounces of alum, and fix drams of chalk to be
prepared. When the lediment has formed, the folu¬
tion is to be decanted, and having become quite cold,
the filk is immerfed in it, and left for 18 hours. It
is then taken out, and dried, and afterwards dyed
with an equal weight of madder. The colour thus
obtained is of a dark (hade. Mr Guliche deferibes
another procefs. For every pound of filk he propofes
a bath of four ounces of alum and one ounce of folu¬
tion of tin. When the liquor has become clear, it is
decanted, and the filk carefully foaked in it for 12
hours, after which it is to be immerfed in a bath with
half a pound of madder foftened by boiling, with an
infufion of galls in white wine. The bath is to be
kept moderately hot for an hour, and then made to
boil for two minutes. The filk being taken from the
bath, is to be wallied in a ilream of water, and dried
in the fun. The colour thus obtained is very perma¬
nent. By leaving out the galls it is clearer. The
brightnefs of the firll colour may be confiderably in¬
creased, by palling the Huff through a bath of brazil¬
wood, to which one ounce of folution of tin is added.
3 H In
426
DYE
Of Simple In this way the colour becomes extremely beautiful
, GoI°ltrs- , and durable. <
Procefs 2I2‘ Silk is fometimes dyed with brazil wood, and
with Brazil ihe colour thus obtained has been diftinguifhed by the
wood. name of Jaf/e crimfon, to dillinguifh it from the more
durable colour which is produced by cochineal. The
filk, after being boiled with foap, is to be alumed. It
is then to be refrefhed at the river, and dipped in a
bath more or lefs charged with brazil juice, according
to the depth of (hade required. If pure water be em¬
ployed, the colour will be too red for crimfon j but to
remedy this, the fluff may be paffed through a weak al-
kalinefolution,or a little alkali may be added to the bath,
or the fluff may be waftied in hard water till it has ac¬
quired the proper (hade. To deepen the (hade of falfe
crimfons, or dark reds, the folution of logw'ood is added
to the brazil bath, the filk being previoufly impregnated
with the latter ; or a little alkali may be added, accord¬
ing to the fhade required.
With co« 213. The crimfon produced by cochipeal is called
pineal. grain crimf0n, to diftipguilh it from falfe crimfon. The
filk, being well cleanfed from the foap at the river, is
to be immerfed in an alum liquor of the full ftrength,
and to remain for a night. It is then to- be walhed,
and twice beetled at the river. The bath is prepared
by filling a long boiler two-thirds with water, to which
are added, when it boils, from half an ounce to ttvo
ounces of powdered white galls for every pound of filk.
When it has boiled for a few moments, from two to
three ounces of cochineal alfo powdered and fifted, for
every pound of filk, are put in, and aftenvards one
ounce of tartar to every pound of cochineal. When
the tartar is diffolved, one ounce of folution of tin is
added for every ounce of tartar. In the preparation of
this fohtion of tin the following proportions are recom¬
mended by Macquer. For every pound of nitric acid
two ounces of fal ammoniac, fix ounces of fine grain tin,
and twelve ounces of water are employed. .When thefe
ingredients are mixed together, the boiler is to be filled
up with cold water, and the proportion of the bath for
every pound of filk is about eight or ten quarts of water.
In this the filk is immediately immerfed, and turned on
the winch, till it appear to be of a uniform colour. The
fire is then increafed, and the bath is kept boiling for
two hours, taking care to turn the filk occafionally.
The fire is afterwards put out, and the filk put into the
bath, where it is allowed to remain for a few hours lon¬
ger. It is then taken out, w-ifhed at the river, twice
beetled, wrung, and dried. Two proceffes are recom¬
mended by Scheffer and Macquer. In that of the for¬
mer, a greater proportion of cochineal is employed in
the dye-bath j but, in that of the latter, a yellow ground
is previoufly communicated to the filk. The colour
which is thus obtained refifts the aftion of foap, and is
more durable than that which is produced by means of
carthamus.
214. To obtain other fhades of red, the above pro¬
ceffes muff be varied. If, after the filk has been wrung
out of the folution of tin, it is fteeped for a night in a
cold folution of alum, in the proportion of one ounce to
a quart of water, wrung and dried, then wafhed and
boiled with cochineal, it will only appear of a pale
■poppy-red. poppy-colour 5 but a fine poppy-red may be produced
by fteeping it twelve hours in the folution of tin, di¬
luted with eight parts of water, then left all night in
I N G. Part IL
the folution of alum, wafhed, dried, and paffed through OfSimpl*
two baths of cochineal, taking care to add to the fe- , a
cond bath a (mail quantity of fulphuric acid. The
fame colour may be produced by dyeing the filk pre¬
vioufly with anotta, and then paffing it fucceffively
through a number of baths prepared with an alka¬
line folution of carthamus, to which lemon juice has
been added, till it acquire a fine cherry-colour. To
brighten the colour, the filk, after being dyed, may
be immerfed in hot water acidulated with lemon
juice.
215. Other fhades of red, as a cherry-red, and flefli-Cherry red,
red, are alfo produced by means of carthamus. For a&-c*
cherry-red, it is not neceffary that the fluff be previoufly
dyed with anotta, and the proportion of colouring
matter is fmaller. A flefti-red colour is obtained by
adding a little foap to the bath, which has the effedt of
foftening the colour, and of retarding the a&ion of the
colouring matter on the fluff. 1 o produce dark (hades,
it is femetimes ufual to mix archil, and by this means
the expence is diminiflied.
216. Thofe who have produced a colour on filkScarieU
which comes neareft to fcarlet, Berthollet obferves,
begin wdth dyeing the filk crimfon. It is then dyed
with carthamus, and laftly it is dyed yellow without
heat. By this procefs a fine colour is obtained ; but
the dye of the carthamus is not permanent, as it is de-
ftroyed by the aftion of the air, and the colour becomes
deeper. The following is Dr Bancroft’s procefs. In a
folution of murio-fulphate of tin, diluted with five times
its weight of water, the filk is to be foaked for two
hours} and after being taken out, it is to be wrung
and partially dried. It is then to be dyed in a bath
prepared with four parts of cochineal, and three of
quercitron bark. In this way a colour approaching to
fcarlet is obtained. To give the colour more body, the
immerfion may be repeated both in the folution of tin,
and in the dyeing bath ; and the brightrefs of the fcar¬
let is increaled by means of the addition of carthamus.
A lively rofe colour is produced by omitting the quer-R0fe_co..
citron bark, and dyeing the filk with cochineal only *, lour,
and by adding a large proportion of water to the co¬
chineal, a yellow (hade is obtained, which changes the
the cochineal to the compound fcailet colour *. * Phil,
Perm. Cot,
4. 0/ the Procefs for dyeing Cotton and Linen Red. 312
217. Madder is moft commonly employed for dye-Madder
ing cotton and linen a red colour 5 and indeed in this red.
kind of dyeing it is the moft ufeful of all colouring
matters. * The affinity of the colouring matter of .mad¬
der for cotton is ftronger than for linen ; but it has
been found that the proceffes which are moft fuccefsful
in dyeing the one are the moft preferable for the other.
There are two kinds of madder reds : the one is called
ft triple madder red j and the other, which is much
brighter, has been diftinguifhed by the name of Turkey
or Adrianople red, becaufe it comes from the Levant,
and has rarely been equalled in brightnefs and perma¬
nency. In communicating this beautiful red colour
to cotton, by means of madder, a great many ufelefs
and ridiculous diredions have been given. Accord¬
ing to fome proceffes, the period of a month is.fcarce-
ly fufficient to finifti all the operations which are
confidered as indifpenfibly neceffary for obtaining this,
dye- 21S.
Chap. I. DYE
Of Simple 218. The principal mordants which are employed in
Colours. dycJng cotton with madder, are oil, gall-nuts, and
alum. The colouring matter of madder cannot be fix-
formadder ed on cotton, till the latter has been impregnated with
*ed. oil. A cold foapy liquor is formed by a combination
of oil and a weak folution of foda. By the ufe of this
alkaline ley the oil is diluted and divided, and can be
eafily and equally applied to all the parts of the cot¬
ton. According to Chaptal, potafh produces the fame
effeft as foda ; and attention to this is of fome impor¬
tance, from the difference of price of the two fub-
llances. All kinds of foda or oil are not fit for this
preliminary preparation. The foda muft be in the
cauftic ftate, and its caufticity muft be the effedf of
calcination j becaufe if it has been rendered cauftic by
means of lime, it becomes of a brown colour. The
foda alfo fhould contain little muriate, for when this
neutral fait prevails, the combination of the oil and
the foda is greatly retarded. The moft proper oil is
not of a fine kind, but that which contains a large
portion of the extra&ive principle. As the ley of fo¬
da is only employed for the purpofe of diluting and
conveying the oil equally to all the parts of the cot¬
ton, there muft be a perfedf combination of the oil
and the foda. Indeed this is of fo much importance,
that many place the whole fecret of a ftrong colour
in the choice of good oil and foda. From this it fol¬
lows, that the oil ftiould be in excefs, otherwife it would
abandon the fluff in w’afliing, and the colour would re¬
main dry.
Vfeiofgal- 219. The cotton, being impregnated with oil, is
tog- fubjetfted to the operation of galling. The ufe of gall-
nuts is attended with feveral advantages. 1. The gal¬
lic acid which they contain decompofes the faponace-
ous liquor with which the cotton is impregnated, and
fixes the oil on the fluff. 2. The other properties
which the galls poffefs, predifpofe the cotton to receive
the colouring matter. 3. The aftringent principle
unites with the oil, and forms with it a compound,
which on drying becomes black, is not very foluble in
water, and has a ftrong affinity with the colouring mat¬
ter of madder.
Praiftical 220. From thefe principles fome pra&ical obferva-
remarks. t|ons may be deduced. 1. Gall nuts furnifh the moft
proper aftringent matter for this kind of dye. 2. To
effeft a fpeedy and perfeft decompofition, the galls
ought to be (trained as hot as poffible. 3. The galled
cotton fhould be fpeedrly dried, for otherwife it might
affume a black colour, which would injure the bright-
nefs of the red. 4. The procefs of galling fhould be
performed in dry weather, becaufe when the weather
is moift, the aftringent principle produces a black co¬
lour, and dries flowly. 5. The cotton (hould be preff-
ed together with great care, that the decompofition
may be equally effefted at every point of the furface.
6. It is neceffary to attend t© the proportion between
the gall nuts and the foap, for if the former predomi¬
nate, the colour is black, and if the foap is in excefs,
the portion of oil uncombined with the aftringent
principle efcapes in the wafhings, and impoveriffies the
colour.
Alum as a 2 21. Alum is alfo employed as a mordant in dyeing
mordant. cotton red. This fubftance not only heightens the red
of madder, but contributes alfo, by its decompofition,
and the fixation of its alumina, to give folidity to the
I N G. 427
colour. When cotton, after it tas been galled, is im- C>! Simple
merfed in a folution of alum, it immediately changes ,
its colour, and becomes gray. No precipitate appears
in the bath, becaufe the operation takes place in the
tiffue of the cloth itfelf. But if the folution of alum be
employed at too high a temperature, part of the galls
efcapes from the fluff, and the decompofition of the
alum is then effected in the bath. This, which (hould
be guarded againft, muft obvioufly diminifii the
proportion of the mordant, and render the colour
poorer.
222. This mordant, which is the moft complicated Applicatidur
known in dyeing, requires great attention in its appli-®1 ,lie aJ°r'*
cation. In this, indeed, confifts the whole difficultyc ;in'“
of dyeing cotton a madder or Turkey red. In this
mordant there is a combination of three principles, oil,
the aftringent principle, and alumina j and on their pro¬
per combination, the perfeftion of the colour de
pends. When any one of them is employed fepa-
rately, the colour is neither fo bright, nor fo complete¬
ly fixed.
223. After thefe preliminary obfervations, we (hall
now give a fuller detail of fome ot the proceffes which
are followed in dyeing cotton Turkey red. The fol-Procefs for
lowing is that which is praftifed at Aftracan, of which dye^nS rtd
an account has been given by Profeffor Pallas.' ^an "ra~
“ The cotton to be dyed red is firft waftied exceed- Prepara-
ingly clean in running w^ater, and, when the weather tion.
is clear, hung up on poles to dry. If it does not dry
before the evening, it is taken into the houfe, on ac¬
count of the faline dews fo remarkable in the coun¬
try around Aftracan, and again expofed to the air
next morning. When it is thoroughly dry it is laid
in a tub, and fifh-oil is poured over it till it is entirely
covered. In this ftate it muft (land all night, but in the
morning it is hung up on poles, and left there the
whole day j and this procefs is repeated for a week, fo
that the cotton lies feven nights in oil, and is expofed
feven days to the atmofphere, that it may imbibe the
oil and free itfelf from all air. The yarn is then again
carried to a dream, cleaned as much as poffible, and
hung up on poles to dry.
224. “ After this preparation a mordant is made of The mor-
three materials, which muft give the grounds of the dant.
red colour.. The pulverised leaves of the fumach are
firft boiled in copper kettles j and when their colouring
matter has been fufficiently extrafted, fome powdered
galls are added, with which the liquor mnft be again
boiled j and by thefe means it acquires a dark dirty
colour. After it has been fufficiently boiled the fire
"is taken from under the kettle, and alum put into
the liquor yet hot, where it is foon difiblved. The
proportion of thefe three ingredients I cannot deter¬
mine with fufficient accuracy, becaufe the dyers make
ufe of different quantities at pleafure. The powder
of the fumach leaves is meafured into the kettle with
ladles; the water is poured in according to a gauge, on
which marks are made to fhew how high the water
muft (land in the kettle to foak fix, eight, ten, &c.
puds of cotton yarn. The galls and alum are added
in the quantity of five pounds to each pud of cotton.
In a word, the whole mordant muft be fufficiently
yellow, ftrong, and of an aftringent tafte.
225. As foon as the alum is diffolved, no time muff
be loft in order that the mordant may not be fuffered
3 H 2 to
428
DYEING.
Of Simple to cool. The yarn is then put into hollow blocks of
t -wood fhaped like a mortar, into each of which fuch a
quantity of the mordant has been poured as may be
fiifficient to moilten the yarn without any of it being
left. As foon as the workman throws the mordant in¬
to the mortar, he puts a quantity of the yarn into it,
and preffes it dowm with his hand till it becomes uni¬
formly moiftened, and the -whole cotton yarn has
Itruck. By this it acquires only a pale yellow colour,
which however is durable. It is then hung up on poles
in the fun to dry, again walked in the llream, and
afterwards dried once more.
226. “ By the yellow dye of the fumach leaves, the
madder dye becomes brighter and more agreeable j but
the galls damp the fuperduous yellow, and together
wdth the alum prepare the yarn for its colour. Some
dyers however omit the ufe of thefe leaves altogether,
and prepare their mordant from galls and alum only,
by firlt boiling the galls in due proportion with the
requifite quantity of water, then diffolving the alum
with boiling water in a feparate veffel, afterwards pour¬
ing both liquors together into a tub, and fuffering the
cotton to remain in them an hour, or an hour and a
half •, after- which it is dried gradually, then wTathed,
and again dried once more. By this procefs the yarn
acquires a dirty reddilb colour.
Madder 227. “ The next part of the procefs is to prepare
^e" the madder dye. The madder, ground to a fine
powder, is fpread out in large troughs, and into each
trough is poured a large cup full of (beep’s blood,
which is the kind that can be procured with the great-
ell facility by the dyers. The madder mud be ftrong-
ly mixed in it by means of the hand, and then (land
fome hours in order to be thoroughly foaked by it.
The liquor then affumes a dark red appearance, and
the madder in boiling yields more dye.
228. “ After this procefs water is made hot in large
kettles, fixed in brick-work *, and as foon as it is warm
the prepared red dye is put into it, in the proportion of a
pound to every pud of cotton. The dye is then fuffer-
ed to boil ftrongly; and when it is boiled enough, which
may be tried on cotton threads, the fire is removed
from under the kettle, and the prepared cotton is de-
pofited near it. The dyer places himfelf on the edge
of the brick-work that enclofes the kettle.*, dips the
cotton yarn, piece by piece, into the dye *, turns it
round, backwards and forwards *, preifes it a little with
his hands *, and lays each piece, one after the other, in
pails (landing ready for the purpofe. As foon as all
the cotton has received the firil tint, it is hung up to
dry : as the red, howrever, is dill too dull, the yam
which has been already dyed once, and become dry, is
put once more into the dyeing-kettle, and mud be left
there to feethe for three hours over a (Irong fire, by
which it acquires that beautiful dark red colour which
is fo much eileemed in the Turkey yarn. The yarn is
now taken from the dye with (licks *, the fuperduous
dye which adheres to it is flraken off -7 the hanks are
put in order, and hung up, one after another, to dry.
When it is thoroughly dry, it is walked in the pure
dream and again dried. The only fault of the Ailra-
Part II,
can dyers is, that the colour is fometimes brighter and Of Simple
fometimes darker, probably becaufe they do not pay Colours. ^
fufficient attention to the proportions, or becaufe the “ ~
madder is not always of the fame goodnefs.
229. “ In the lad place, the above-mentioned foda Boiling in
(kalakar) is diffolved with boiling water in tubs dellin- ley of ioda.
ed for that purpofe, and it is ufual here to allow twenty
pounds of foda to forty pounds of cotton, or half the
wreight. Large earthen jars, which are made in Perfia
of very (Irong clay, a yard and a half in height, al-
rnoll five fpans wnde in the belly, and ending in a neck
a (pan and a half in diameter, enclofed by means of ce¬
ment in brick-work over a fire-place, in fuch a manner
that the necks only appear, are filled with the dyed
cotton yam. The ley of diffolved foda, which is
blackifh and very (harp, is then poured over it till the
jars be filled } and fome clean rags are preffed into
their mouths, that the uppermoil (kains of yarn may
not lie uncovered. A fire is then made in the fire-place
below, and continued for 24 hours •, and in the mean
time the (leam which arifes from the jars is feen col-
le£led among the rags in red drops. By this boiling
the dye is ilill more heightened, and is made to (trike
completely *, every thing fuperduous is removed, and
all the fat matter which (till adheres to the yarn is
wafoed out : nothing more is then neceffary for com¬
pleting the dye of the yarn but to rinfe it well feveral
times in running -water, and then to dry it.
230. “ That the dye of madder might be made very The fame
penetrating by other methods, and through the means colour by
of other oily and refinous fubilances, is (hewn by the other
procefs of the Tungufians to dye horfe, goat’s and rein¬
deer’s hair, which they ufe for ornamenting their
dreffes, of a beautiful red colour, with the roots of the
crofs-wort, or northern madder (galiiwi), and nar-
rowT-leaved woodroof {afperula tinfforia'), wThich have a
refemblance to thofe of madder. They boil the fre(h
or dried roots with about the fame quantity of agaric
{agaricus officinaruni), which, as is well known, is
abundant in refmous gummy particles, and is ufed by
the people of Jakut initead of foap *, they then lay in it
the white hair which they wiffi to dye, and fuffer it to
feethe (lowly until it be fufficiently red. Cotton cloth
is dyed with madder at Aftracan in the fame manner
but many purfue a fraudulent procefs, by dyeing with
red wood, and then fell their cloth as that which has
been dyed in the proper manner.”
231. The procefles which are employed in the Gre-Tic G'1’6"
cian manufactories for dyeing Turkey red, as they^^rae“
have been defcribed by C. Felix, in a memoir in the
French annals of chemiilry, are fomewhat different
from the above. “ In thefe manufactories,” he obferves,
“ the workmen dye at one time a mafs of (kains weigh¬
ing thirty-five occas (k) j each occa being equal to
about fifty ounces. The firft procefs is that of clean- Prepara-
ing the cotton, for which purpofe three leys are em- ^on*
ployed ; one of foda, another of alhes, and a third of
lime. The cotton is thrown into a tub, and moiften¬
ed with the liquor of the three leys in equal quantities 5
it is then boiled in pure water, and waffled in running
water.
232.
(k) Equal to 1091b. 6oz.
Chap. !•
dyeing.
429
Second
bath.
Of Simple 232. “ The fecond hath given to the cotton is com-
Colouxs. poled of foda and iheep1s dung diilolved in tvater. lo
' facilitate the folution, the foda and dung are pounded in
a mortar. The proportions of thefe ingredients em¬
ployed, are, one occa of dung, fix of foda, and forty
of water. When the ingredients are well mixed, the
liquor expreffed from them is ftrained, and being pour¬
ed into a tub, fix occas of olive oil are added to it, and
the whole is well ilirred till it becomes of a whitiih
colour, like milk. The cotton is then befprinkled with
this water, and when the Ikams are thoroughly moili¬
en ed, they are wrung, preffed, and expofed to dry.
The fame bath mull be repeated three or four times,
becaufe it is this liquor wdiich renders the cotton more
or lefs fit for receiving the dye. Each bath is given
with the fame liquor, and ought to continue five or fix
hours. It is to be obferved that the cotton, after each
bath, mull be dried without being walked, as it ought
not to be rinled till after the lall bath. The cotton is
then as white as if it had been bleached in the fields.
233. “ The bath of Iheep’s dung is not ufed in our
manufactories (l) ; it is a practice peculiar to the Le¬
vant. It n;ay be believed that the dung is of no utili¬
ty for-fixing the colours-, but it is known that this fub-
Itance contains a great quantity of volatile alkali,. in a
difengaged Hate, which has the property of giving a
rofy hue to the red. It is therefore probable that it
is to this ingredient that the red dyes of the Levant are
indebted for their fplendour and vivacity. This much,
at any rate, is certain, that the Morocco leathei of tue
Levant is prepared with dog’s dung -, becaufe it has
been found that this dung is proper for heightening the
colour of the black. The bath of dung is followed
by the procefs of galling.
Galling and 234. “ The galling is performed by immerfing the
aluming. cotton in a bath of warm water, in which five occas of
pulverifed gall-nuts have been boiled. This operation
renders the cotton more fit for being faturated with the
colour, and gives to the dye more body and flrength.
After the galling comes aluming, which is performed
twice,^ with an interval of two days, and which confills
in dipping the cotton into a bath of water in which
five occas of alum have been infufed, mixed with five
occas of water alkalized by a ley of foda. Lhe alum¬
ing mull be performed with care, as it is this operation
which makes the colouring particles combine bell with
the cotton, and which fecures them in part from the
deftruflive a£lion of the air. W hen the (econd alum¬
ing is finifhed, the cotton is wrung j it is then.preffed,
and put to foak in running water, after being inclofed
in a bag of thin cloth.
235. “ The workmen then proceed to the dyeing.— Of Simple
To compofe the colours they put in a kettle five occas 0 “Ulh; ,
of water and thirty-five occas of a root which the Dyeing.
Greeks call ali-zari, or painting colour, and which in
Europe is known under the name of madder. The
madder, after being pulverifed, is moiitened with one
occa of ox or Iheep’s blood. The blood ftrengthens
the colour, and the dofe is increafed or leflfened accor¬
ding to the lhade of colour required. An equal heat is
maintained below the kettle, but not too violent 5 and
when the liquor ferments, and begins to grow warm,
the Ikains are then gradually immerfed, before the
liquor becomes too hot. They are then tied with pack¬
thread to fmall rods, placed croffwife above the kettle
for that purpofe, and when the liquor boils well, and
and in an uniform manner, the rods from which the
fkains were fufpended are removed, and the cotton is
fufifered to fall into the kettle, where it mull remain
till two-thirds of the water is evaporated. WTien one-
third only of the liquor remains, the cotton is taken
out and wafhed in pure water.
236. “ The dye is afterwards brought to perfeclion \lkaline
by means of a bath alkalized with foda. This mani-bath.
pulation is the moll difficult and the moll delicate of
the whole, becaufe it is that which gives the colour its
tone. The cotton is thrown into this new bath, and
made to boil over a Heady fire till the colour aifumes
the required tint. The whole art confills in catching
the proper degree : a careful workman, therefore, mull
watch with the utmoll attention for the moment when
it is neceflary to take out the cotton, and he will ra¬
ther burn his hand than mifs that opportunity. It
appears that this bath, which the Greeks think of fo
much importance, might be lupplied by a ley of foap }
and it is probable that faponaceous water would give
the colour more brightnefs and purity.
2 37. “ When the colour is too weak, the Levantines Methods of-
know how to llrengthen it by increafing the dofe of improving
the colouring fubllances} and when they wilh to givethe co our'
it brightnefs and fplendour, they employ difterent roots
of the country, and, in particular, one named faj[ariy
fpecimens of which I have fent to France. The ali-
zari, which is the principal colouring matter employed
in the Greek dye-houfes, is collefted in Natolia, and
is brought to Greece from Smyrna : fome of it comes
alfo from Cyprus and Mefopotamia. The fuperiority
of this Levantine plant to the European madder is ac¬
knowledged by all thofe acquainted with the art of
dyeing, and may arife from two caufes -, the manner in
which it is cultivated, and the method employed for its
deficcation (m)”.
9.2 R. Ta
(l) The French manufaftories. . j n urn j • /-
>m) “ The chief manufaclories,” continues our author, “ for dyemg fpun cotton red, eltabliffied m Greece,,
are in Theflfaly. There are fome at Baba, Rapfani, Tournavos, Lariffa, Pharfaha, and m all the villages fitua-
ted on the fides of OiTa and Pelion. Thefe two mountains may be confidered as the alembics that diftil the
eternal vapours with which Olympus is crowned, and which diilribute them throughout the beautiful valleys
fituated around them. Of thefe valleys, that of Tempe has at all times been diilingmfhed by the beauty of its
ihady groves and of its llreams. Thefe llreams, on account of their limpidnefs, are very proper for dyemg, and
fupply water to a great number of manufaftories, the moll celebrated of which are thofe of Ambelakia.
“ Ambelakia, on account of the activity which prevails in it, has a greater refemblance to a town of Holland
than a village of Turkey. This village, by its induflry, communicates life and a&mty.to all the neighbouring
country, and gives birth to an immenfe trade, which connefts Germany with Greece m a thoufand ways. Its.
430 DYE
Oi Simple 238. To thefe procefles we fliall add the account
Colours. 0f another, which was long fuccefsfully praftifed at
Papillon’s Gla%ow by^ Mr Papillon, a native of France, and
procefs. was communicated by him, for a fuitable premium, to
the commiflioners and truftees for manufactures in Scot¬
land, to be by them publiihed for the benefit of the
public, at the end of a certain term of years. This
tranfaclion took place in 1790, and the period having
expired, thetruilees announced it to the public in 1803.
r u -fs, which coniilts of nine different fteps, is the
Step I.
For 100 lib. cotton you mufl have
100 lib. of alicante barilla,
20 lib. of pearl alhes,
100 lib. quicklime.
The barilla is mixed with foft water in a deep tub,
which has a fmall hole near the bottom of it, flopped
at firfl with a peg.—This hole is covered in the infide
with a cloth fupported by two bricks, that the alhes
may be prevented from running out at it, or flopping
it up while the ley filters through it.
Under this tub is another to receive the ley •, and
pure water is repeatedly paffed through the firft tub
to form lees of different ftrength, which are kept fe-
parate at firfl; until their ftrength is examined. The
ftrongeft required for ufe muft fwim or float an egg,
and is called the ley of fix degrees of the French Hydro¬
meter, or Pefeliqueur. The weaker are afterwards
brought to this ftrength, by paffing them through frelh
barilla. But a certain quantity of the weak, which is
of 2 degrees of the above hydrometer, is referved for
diffblving the oil, and gum, and the fait, which are
ufed in fubfequent parts of the procefs. This ley of 2
degrees is called the weak barilla liquor, the other is
called the ftrong.
Diffolve the pearl-afhes in 10 pails, of 4 gallons each,
of foft water, and the lime in 14 pails.
Let all the liquors Hand till they become quite clear,
and then mix 10 pails of each.
Boil the cotton in the mixture five hours, then walh
it in running water and dry it.
Step II. Bainbiey or Gray Steep.
Take a fuffkient quantity (20 pails) of the ftrong
xne proc
following
I N G. Part II.
barilla water in a tub, and diffolve or dilutein t * pails Of Simple
full of Iheep’s dung, then pour into it 2 quart bottles Colours,
of oil of vitriol, and 1 lib. of gum arabic, and 1 lib. of v
fal ammoniac, both previoufly diffolved in a lufticient
quantity of the weak barilla water, and lartly, 25 lib of
olive oil, which has been previoufly difibived or well
mixed with 2 pails of the weak barilla water,
1 he materials of this fteep being well mixed, tramp
or tread down the cotton into it, until it is well
foaked 5 let it fteep 24 hours, and then wring it hard
and dry it.
Steep it again 24 hours, and again wring and dry it.
Steep it a third time 24 hours, after wrhich wring and
dry it, and laftly wafh it well and dry it.
Step HI. The White Steep.
This part of the procefs is precifely the fame wfith
the laft, in every particular, except that the Iheep’s dung
is omitted in the compofition of the fteep.
Step IV. Gall Steep.
Boil 25 Kb. of galls bruifed in 10 pails of river wa¬
ter, until 4 or 5 are boiled away j ftrain the liquor int»
a tub, and pour cold water on the galls in the ftrainer,
to wrafh out of them all their tin&ure.
As foon as the liquor is become milk wrarm, dip your
cotton hank by hank, handhng it carefully all the
time, and let it fteep 24 hours.
Then wring it carefully and equally, and dry it well
without w’afliing.
Step V. Tirft /Hum Steep.
Diffolve 25 Kb. of Roman alum in 14 pails of wrarna
water, without making it boil, Ikim the liquor well, and
add 2 pails of ftrong barilla water, and then let it cool
until it be lukewarm.
Dip your cotton and handle it hank by hank, and
let it fteep 24 hours, and wring it equally and dry it
w'ell without walhing.
Step VI. Second Alum Steep,
Is performed in every particular like the laft, but
after the cotton is dry, you fteep it 6 hours in the river,
and walh and dry it.
Step.
population, which has been tripled within thefe fifteen years, amounts at prefent to 4000, and all thefe people
exift by dyeing. None of thofe vices or cares produced by idlenefs are known here. The hearts of the inhabit
tants are pure, and their countenances unclouded. Servitude, which degrades the countries w'atered by the Pe-
neus, has not yet afcended to thefe hills: no Turk can relide or live among thefe people; and they govern them-
felves, like their anceftors, by their protoyeros and their owm magiftrates. Twice have the favage muffulmans of
Lariffa, envious of their eafe and happinefs, attempted to fcale their mountains in order to plunder their houfes ;
and twice have they been repulled by hands which luddenly quitted the ihuttle to aflume the mtilket.
“ All hands, and even thole of the children, are employed in the dye-houfes of Ambelakia; and while the men
dye the cotton, the women are fpinning and preparing it. The ufe of wheels is not known in this part of
Greece ; all the cotton is fpun on a diftaff: the thread, indeed, is certainly not fo round or equal, but it is fofter,
more filky, and more tenacious ; it is lefs apt to break, and lafts longer; it is alfo more eafily whitened, and
more proper for being dyed. It is a pleafing fpeclacle to fee the wromen of Ambelakia, each fpinning from a
diftaff, and fitting convening together on the threlhold of their doors ; but as foon as a ftranger appears, they
inltantly retire and conceal themfelves in their houfes, manifefting, like Galatea, in their precipitate retreat, a
defire of flying and of fliewing themfelves
Etfugit adfalicesy et fe cupit ante videri.”
I
Chap. I. D ^ E
Of Simple gT]rP VII. Dyeing Steep.
Colours. r
w—v  The eottcn Is dyed by about 10 lib. at once, tor
which take t \ gallons of ox blood, and mix it in the
copper with 28 pails of milk warm water, and ftir it
well, then add 25 lib. of madder, and ftir all well to¬
gether. Then having beforehand put the 17 lib. of
cotton on hicks, dip it into the liquor, and move
and turn it conllantly one hour, during which you gra¬
dually increafe the heat, until the liquor begin to boil
at the end of the hour. Then fink the cotton, and
boil it gently one hour longer; and, laitly, waih it
and dry it. ... ,
Take out lb much of the boiling liquor, that want
remains may produce a nfilk-warm heat with the trelh
water with which the copper is agam filled up, and
then proceed to make up a dyeing liquor as above, lor
the next 10 lib. of cotton.
Step VIII. ‘The fixing Steep.
Mix equal parts of the gray fteep liquor, and of the
white fteep liquor, taking 5 or 6 pails of each. I read
down the cotton into this mixture, and let it fteep fix
hours, then wring it moderately and equally, and dry it
without wafhing.
Step IX. Brightening Steep.
Ten lib. of white foap muft be diflblved raoft care¬
fully and completely in i 6 or 18 pails of warm water }
if any little bits of the foap remain undiflblved, they
will make fpots in the cotton. Add four pails of ftrong
barilla water, and ftir it well. Sink your cotton in this
liquor, keeping it dow n with crois fticks, and cover it up
and boil it gently two hours, then walh and dry it, and
it is finiftied.
Vessels.
The number of veflels neceflary for this bufinefs is
greater in proportion to the extent of the manufacto¬
ry j but, in the fmalleft work, it is neceflary to have
four coppers of a round form.
17?, The largeft, for boiling and for finilhing, is 28
inches deep by 38 or 39 wide in the mouth, and 18 in¬
ches wider in the wldeft part.
‘idy The fecond, for dyeing, is 28 deep, by 23 or
24 in the mouth.
3</, The third, for the alum fteep, is like the fe-
cend.
4/A, The fourth, for boiling the galls, is 20 deep,
by 28 wide.
A number of tubs or larger wooden veflels are ne¬
ceflary, which muft all be of fir, and hooped with wood
or with copper.
Iron rnuft not be employed in their conftruftion, not
even a nail 5 but where nails are neceffary, they muft
be of copper.
By the pail is always underftood a wooden veffel,
which holds four Englifh gallons, and is hooped with
copper.
In fome parts of the above procefs, the ftrength
of the barilla liquor or liquors is determined, by tell¬
ing to what degree a pefeliqueur or hydrometer funk
in them.
The pefeliqueur is of French conftruftion. It is
funilar to the glafs hydrometer ufed by the fpirit dealers
I N G. 431
in this country *, and any artift who makes thefe inftru- Of Simple
roents, wall find no difficulty in conftru<fting one with, Colours. ^
a fcale fimilar to that employed by M. Papillon, when
he is informed of the following circumftances :
iy?, The inftrument, wffien plunged in good foft wa¬
ter, fuch as Edinburgh pipe water, at temperature 60
degrees finks to the o, or beginning of the Icale, 'which
ftands near the top of the ftem.
zd, When it is immerfed in a faturated folution of
common fait, at the fame temperature of 60 degrees
it finks to the 26th degree of the fcale only, and this
falls at fome diftance from the top of the ball.
This faturated folution is made by boiling in pure
water, refined fea or common fait, till no more is diflbl¬
ved, and by filtering the liquor when cold through
blotting paper.
It Ihould alio be obferved, that whenever direftions
are given to dry yarn, to prepare it for a fucceeding
operation, that this drying ftiould be performed with
particular care, and more perfectly than our dryeft wea¬
ther is in general able to eftebf. It is done therefore in
a room heated by a ftove to a great degree.
239. There is ftill another procefs, which is recom-Hauff-
mended by Hauflinann, this procefs, (fays he) obtains pm-
a beautiful and durable red. He makes a cauftic ley
of one part of common potaffi diflblved in four of boil- retp
ing w^ater, and a half part of quicklime, which is after¬
wards flaked in it. He then diflblved one part of pow ¬
dered alum in two of boiling wrater, and to this folu¬
tion while it was yet warm, he added that of the can-'
file ley. The folution of alumina being left at reft,
formed, on cooling, a precipitate of fulphate of potaih.
A 33d part of linleed oil wras then mixed with the al¬
kaline folution of alumina, which then formed a milky
faponaceous liquid. When the mixture is to be ul’ed,
it ought to be w'ell ftiaken, becaufe the oil feparates.
The ftuffs of cotton or linen muft be fucceffively im¬
merfed in it, and equally prefled, and muft be dried un¬
der ftielter from rain in fummer, and in a warm place
in winter j and being left in that ftate for 24 hours, are
then waflied in pure running water, and again dried.
The lame procefs in the immerfion in alkaline ley is a-
gain to be repeated, taking care to introduce firft thoie
itylfs which were iaft in the firft folution. The whole
of the mixture fhould be confumed each time, as it would
attract carbonic acid from the air, and fuftbr the alumi¬
na to be precipitated.
240. Two immerflons in the alkaline Iblution of alu¬
mina mixed with linfeed oil, afford a beautiful red ; but
by impregnating the ftuffs a third, or even a fourth
time, in the fame manner, the moft brilliant colours •
are obtained. The intenfity of the colour is in pro¬
portion to the quantity of madder. A quantity of
madder equal in weight to the fluffs, will yield a red,
which, by clearing becomes of a rofy (hade; and lhades
of crimfon of different degrees of brightnefs are obtain¬
ed, by ufing two, three, or four times the wreight of
madder ; but unlels the wrater employed in the proedfes
contains fome portion of lime, the addition of the chalk
ffiould never be omitted.
241. The fcarlet colour communicated to cotton by Scarlet
means of cochineal, is far from being permanent ; but codu*"
if this colour is wiffied to be communicated to cotton,11 a"
Dr Bancroft recommends to fteep the cotton, previoufl)r '
moiftened, for half an hour in a diluted folution of
jnurio--
43^
Of Simple
Colours.
■Crimfon.
* Phil, of
Perm. Col.
3f7*
Sub (lances
employed
in dyeing
yellow.
Weld.
DYE
murio-fulphate of tin, and then having wrung the cot¬
ton, to plunge it into water, in which as much potafh
has been diflblved as will neutralize the acid adhering to
the cotton, fo that the oxide of tin may be more copi-
oufly fixed on the fibres of the cotton. The fluff being
afterwards rinfed in water, may be dyed with cochineal
and quercitron bark, in the proportion of four pounds
of the former to two and a half or three pounds of the
latter. A full bright colour is thus given to the cot¬
ton, which will bear flight wafhings with foap, and
expofure to the air. Indeed the yellow part of the co¬
lour derived from quercitron bark will bear long boil¬
ing with foap, and will refill the aftion of acids.
242. With the aluminous mordant, as it is ufually ap¬
plied by callico printers for madder reds, cotton dyed
with cochineal receives a beautiful crimfon colour,
which will bear feveral waihings, and refill the w eather
for fome time. It is not, however, to be confidered as
a fixed colour. Dr Bancroft is of opinion, that the
addition of a fmall portion of cochineal in dyeing mad¬
der reds upon the finer cottons, would be highly advan¬
tageous to the callico printers. By this addition the
madder reds are rendered more beautiful, and the fawn
colour, or brownifh yellow hue, which injures thele reds,
would be thus overcome. *.
Sect. II. Of Yellow.
243. In dyeing yellow7, it is neceffary to employ mor¬
dants, becaufe the affinity of yellow colouring matters for
either animal or vegetable fluffs is not Efficiently flrong
to produce durable colours. Yellow colours, therefore,
belong to that clafs which Dr Bancroft has denomina¬
ted adjeElive -colours. As in the former fed!ion, wre fhall
firfl give a fhort defcription of the nature and properties
of the fubflances employed in dyeing yellow, and then
point out the moft approved modes of communicating
their colours to w'oollen, filk, cotton, and linen fluffs.
The fubflances capable of giving a yellow colour to
different fluffs are very numerous *, they do not all pro¬
duce fimilar quantities of colouring matter ; their dye
is not equally free ; the colours they impart incline
more or lefs to orange or green j they poffefs various
degrees of brightnefs and permanency, and differ con-
fiderably in price } circumflances by which the choice of
the dyer ought always to be regulated. But thofe
commonly employed in dyeing yellow7, are weld, fuflic,
anotta, and quercitron bark.
I. Of the Sulfances employed in dyeing Yellow.
244. Weld (refed a luteola, Lin.) is a plant which
grow s w7ild in Britain, and in different European coun¬
tries. Its leaves are long, narrow7, and of a bright green,
but the whole plant is made ufe of in the dyeing of yellow7.
There are two kinds of w7eid, cultivated and rvild, the
former of which is deemed more valuable than the lat¬
ter, as it yields a much greater proportion of colouring
matter. When this -plant is fully ripe, it is pulled,
dried, and bound up in bundles for the ufe of the dyer.
The wild fpecies grows higher and has a ftronger flalk
than that which is cultivated, by which the one may be
readily diflinguiflied from the other.
Properties. 245. A ffrong deco&ion of weld is of a brownifh yeh
low7 colour, and if very much diluted with water, the co-
I N G. Part II*
lour, inclines to a green. An alkali gives to this decoc- Of Simple
tion a deeper colour, and the precipitate it occafions is Col°nrs.
not foluble in alkalies. Moft of the acids give it a ' "l''
paler tinge, occafioning a little precipitate which is folu¬
ble in alkalies. Alumina has fo ftrong an affinity for the
colouring matter of weld, that it can even abftrac! it
from fulphuric acid, and the oxide of tin produces a fi¬
milar efteft. The greater part of metallic falls throw
down fimilar precipitates, which vary in their (hades of
colour according to the metal employed. A folution of
common fait renders the liquor turbid, and a folutictfi of
tin yields fa copious yellow7 precipitate, while the liquor
long continues turbid, and (lightly coloured.
246. Euftic {morus tin&ona, Lin.) is procured fromFuftic-
a tree of confiderable magnitude, which grows in the
Weft Indies. The w7ood is yellow, as its name imports,
with orange veins. Ever fince the difeovery of Ame¬
rica it has been ufed in dyeing, as appears from a pa¬
per in the Tranfadtions of the Royal Society, of which
Sir William Petty was the author. Its price is mode¬
rate, the colour it imparts is permanent, and it readily
combines with indigo, which properties give it a claim
to attention as a valuable ingredient in dyeing. Before
it can be employed as a dye-ftuff, it muft be cut into
chips and put in a bag, that it may not fix in, and
tear the fluff, to which it is to impart its colouring
matter.
247. When a decoction of yellow wood or fuftic is Properties. ;
made very ftrong, the colour is of a reddifh yellow7,
and when diluted it is of an orange yellow7.
w7hich it readily yields to water. It becomes turbid
by means of acids, its colour is of a pale yellow, and
the greenifh precipitate may be re-diffolved by alkalies.
The fulphates of zinc, iron, and copper, as wTell as
alum, throw7 down precipitates compofed of the colour¬
ing matter and the different bafes of the falls employed.
In examining the caufes of the fixity of yellow co¬
lours, obtained from vegetables, Chaptal difeovered
that the durability of the pale yellow depended on the
tanning principle, -w-hich is found united with the yel¬
low colouring matter. He obtained by analyzing fuf¬
tic, 1. A refinous or gummy matter, which can com¬
municate a beautiful yellow colour. 2. An extractive
matter, which is alfo yellow, and affords a beautiful
colour. 3. A tanning principle of a pale yellow7 colour,
which becomes black by boiling, or expofure to the
air. This latter diminifhes the brilliancy of the two
former ^ but it may be feparated by a fimple procefs.
Chaptal boiled with the wood fome animal fubftance
containing gelatinous matter, fuch as bits of fkin, ftrong
glue, &c. The tanning principle was thus precipitated
with the gelatinous matter, and the bath held in folu¬
tion only the colouring matters wdiich yield a bright,
full yellow 5 and by means of this procefs he procured
colours from feveral vegetables, equally bright with
thofe which are communicated by yellow wood and
quercitron bark *. * Phil.
248. Anotta is a fpecies of pafte of a red colour, Mag. i.430.
obtained from the berries of the bixa orcllana Lin. ■A-nott‘1,
which is a native of America. The anotta of com¬
merce is imported from America to Europe in cakes of
two or three lib. weight, where it is prepared from the
feeds of the tree mentioned above *, but the Americans
are faid to be in poffeffion of a fpecies of anotta fupe-
rior to that which they export, both for the brilliancy
and
Properties.
Quercitron
bark.
Phil. *f
Perm. Csl.
S'S-
Chap. I. DYE
of simple and permanency of the colour it imparts They braife
Colours, the feeds with their hands moiftened wit i , P _
    ing with a knife the pafte as it is foimed and drying
it in the fun; but the feeds are pounded with water
when defigned for /ale, and allowed to undergo the
procefs of fermentation.
247. Anotta yields its colouring matter more rea¬
dily to alcohol than to water, on which account it is
ufed in yellow varnifhes to which an orange tinge is^ in¬
tended to be given. Acids form a precipitate with a
deco&ion of anotta of an orange colour, which is io-
luble in alkalies*, but folutions of common fait produce
no fenfible change. It yields an orange precipitate
with a folution of alum, and the fulphates of copper
and iron produce effeas of nearly a fimilar nature.
With a folution of tin the precipitate is of a lemon co¬
lour, and (lowly depofited. # „
248. Quercitron, as it is denominated by Dr .Ban¬
croft, is the quercus nigra of Linnaeus, and is a large
tree which grows fpontaneouily in North America.
The bark of it yields a confiderable quantity of colour¬
ing matter, which was firil difcovered by Dr Bancroft
in the year 1784, in whom the ufe and application of
it in dyeing were exclufively veiled for a certain term
of years by virtue of an adt of parliament. To prepare
it for ufe, the epidermis is taken off and pounded in a
mill, the refult of which procefs is a number of fila¬
ments and a fine light powder* but as thefe do not/on-
tain equal quantities of colouring matter, it will be
proper to employ them in their natural propor¬
tions. . ...
Prooerties 240. Quercitron bark readily imparts its colouring
P ’ matter to water at 1 oo° of Fahrenheit, which is of a yel-
lowifh brown, capable of being darkened by alkalies, and
brightened by acids. With muriate of tin the precipi¬
tate is copious, and of a yellow colour 5 with fulphate
of tin it is a dark olive *, and with fulphate of copper it
is yellow, but inclining to an olive. Nitro-muriate ot
tin yields a yellow extremely beautiful, probably owing
to the oxide of tin combining with the colouring mat¬
ter in a greater proportion than fome other falts.
Otherfub 250* Befides the fubftances already mentioned as em-
ftances. * ployed in the dyeing of yellow, we may add faw-wort to
the number (ferratula tinElona^ Lin.) a plant which
yields a colouring matter nearly fimilar to that of weld,
and may of confequence be ufed as a proper fubllitute.
Dyers broom (genijfa tinBoria') produces a yellow of
very indifferent nature, and is therefore only employed
in dyeing fluffs of the coarfeff kind. Turmeric {cur¬
cuma longa) is a native production both of the Fall and
Weft Indies, and yields a more copious quantity of co¬
louring matter than any other yellow dye-fluff j but it
will probably never be of any effential fervice in dyeing
yellow, as no mordant has yet been diicovered, capa¬
ble of giving permanency to its colour.
251. Chamomile {anlhemis tinBoria') yields a faint
yellow colour, the hue of which is not unpleafant, but
is far from being durable, and even mordants are not
capable of fixing it. Sulphate of lime, tartar and alum,
bid faireft for fuccefs.
252. Fenugreek {trigonella fecnugractttn) yields ieeds
which, when ground, communicate to fluffs a pale
yellow of tolerable durability *, and the beft mordants
are found to be alum and muriate of foda, or common
fait. American hiccory {Juglans alba) is a tree, the
Vox,. VII. Part 11.
I N G. 433
bark of which yields a colouring matter in every re- ^miple
fpeCt refembling that of the quercus nigra, but in cjuan-
Bty greatly inferior. French berries {rhamnus wjecio-
rius) produce a tolerable yellow colour, but it is by no
means permanent. When ufed in the procefs of
dyeing, they are to be employed in the fame manner as
weld. According to Scheffer, a fine yellow colour
may be imparted to filk, thread and wTool, oy means of
the leaves of the willow* but Bergman informs us that only
the leaves of thefweet willow{Jahxpent&ndrci) are pioper
for producing a permanent colour, as a few wreeks ex-
pofure to the fun extrafts that which is produced by
the colouring matter from the leaves of the common
willow. ’ 4 f
253. In Switzerland and rn England, the leeds 01
purple trefoil are fometimes employed in the art of dye¬
ing, on which Vogler made a number of experiments,
in order to afcertain what colours they would produce:
and he found that a fine deep yellow was afforded by a
bath made of a folution of theie feeds with potato * that
fulphuric acid yielded a light yellow, and fulphate of
copper or blue vitriol, a yellow inclining to green. M.
Dizc informs us, that the feeds of trefoil impart to
wool a beautiful orange, and to filk a greenifti yellow *
and that while aluming is neceffary in the procefs ot
dyeing with the feeds of trefoil, a folution of tin cannot
be employed.
II. Of the Proceffes for Dyeing Wool Yellow.
2 ^4, In dyeing woollen fluffs with weld, the mor-With weld,
dants employed are alum and tartar, and by their means
a pure, permanent yellow is obtained. L he ooiling is
to be conducted in the ufual way * and accoidmg to
Hellot, four ounces of alum to one ounce of tartar are
to be employed. Other dyers, however, employ half
as much tartar as alum, ihe colour is rendered paier,
but more lively, by means ot the taitar.
2*5. The bath is prepared by boiling the plant m- preparation
clofed in a thin linen bag, and keeping it from rifing of the bat*h,
by means of a wooden crofs. Some boil it till it links
to the bottom of the veffel, while others, after it is boil¬
ed, take it out, and throw it away. From three to
four libs, of weld, and fometimes lefs, are allowed for
every lib. of fluff * but the quantity muft be regulated
by the intenfity of the {hade defired. Some dyers add
a fmall quantity of quicklime and aihes, which are
found to promote the extraction of the colouring
matter. Thefe fubftances at the fame time heighten
the colour, but render it lefs lufceptible of refilling the
action of acids.
2 56. With other additions, and different management,For differ,
different ihades may be obtained. Thus, lighter {hades eat fhadw.
are produced by dyeing after deeper ones, adding wa¬
ter at each flipping, and keeping the bath at the boil¬
ing temperature. Thefe ihades, however, are lefs live¬
ly than when frefli baths are employed, with a fmtable
proportion of weld. The addition of common fait or
fulphate of lime to the weld bath communicates a rich¬
er and deeper colour. With alum it is,paler and moie
lively, with tartar Hill paler, and with fulphate of non
the lhade inclines to brown. According to Schefler,
by boiling the fluff two hours, with one-fourth of its
weight of a folution of tin, and the fame proportion of
tartar, and then wafhing and boiling it with an equal
weight of weld, a fine yellow is produced ) but if the
2 I fluff
434 DYE
Of Simple fluff be in the ffate of cloth, its internal texture is not
. CoI°urs- penetrated. Poerner recommends a fimilar preparation
as for dyeing fcarlet, and by thefe means the colour is
brighter, more permanent, and lighter.
With quer- 257. Dr Bancroft recommends the quercitron bark
citron bark. as one 0f the cheapeil and befl fubftances for dyeing
wool yellow. The following is the limple procefs which
he has propofed for its application. The bark is to be
boiled up with about its weight, or one-third more,
of alum, in a Juitable proportion of water, for about
10 minutes. The fluff previoully fcoured is then to be
immerfed in the bath, taking care to give the higher
colours firft, and afterwards the paler flraw colours.
By this cheap and expeditious procefs, colours which
Cheap pr°- are not wanted to be of a full or bright yellow, may
be obtained. The colour may be conliderably height¬
ened by palling the unrinfed fluff a few times through
hot water, to which a little clean powdered chalk, in
the proportion of about 1 ^ lb. for each 1 a© ib. of fluff
has been preyioufly added. The bark, when ufed
in dyeing, being flrft reduced to powder, fliould be
tied up in a thin linen bag, and fufpended in the liquor,
fo that it may be occaffonally moved through it, to dif-
fufe the colouring matter more equally.
Procefs for 2$$. But although the above method poffeffes the
uoloursT"1 advantaSes of cheapnefs and expedition, and is flilly
fufficient for communicating pale yellows *, to obtain
fuller and more permanent colours, the common mode
or preparation, by previoufiy applying the aluminous
mordant, ought to be preferred. The fluff, therefore,
fliould be boiled for about one hour or one hour and a
quarter, with cne-fixth, or one-eighth of its weight of
alum, diifolved in a proper proportion of water. The
fluff is then to be immerled without being rinfed, into
the dyeing bath, with clean hot water, and about the
tame quantity of powdered bark tied up in a bag, as
that of the alum employed in the preparation. The
fluff is then to be turned as ufual through the boiling
liquor, until the colour appears to have acquired fuffi¬
cient intenfity. One pound of clean powdered chalk
for every 100 lbs. of fluff is then to be mixed with the
dyeing bath, and the operation continued for eight or
ten minutes longer. This addition of the chalk raifes
and brightens the colour.
259. Orange Yellow. To communicate a beauti¬
ful orange yellow to woollen fluffs, 1 o lbs. of querci¬
tron bark, tied up in a bag, for every 100lb. of fluff are
to be put into the bath with hot water. At the end
of fix or eight minutes, an equal weight of murio-ful-
Eor differ- phate of tin is to be added, and the mixture well ftir-
tnt flunks. re(l for two or three minutes. The cloth, previoufiy
fcoured, and completely wetted, is then immerfed in
the dyeing liquor, and brifkly turned for a few minutes.
By this procef’s the colouring matter fixes on the cloth
fo quickly and equally, that after the liquor begins to
boil, the higheft yellow may be produced in lefs than
15 minutes.
260. High fhades of yellow, fomewhat fimilar to
thofe obtained from quercitron bark by the above pro-
tefs, are frequently given with young fuftic (/ bus coti-
nus, Lin.) and dyers fpirit, or nitro-muriate of tin 5 but
this colour is much lefs beautiful and permanent, while
it is more expenftve than what is obtained from the
hark.
261. Bright golden Yellow.'— This colour is produ-
ced by employing 1 o pounds of bark for every 100 lbs. Of Simple
of cloth, the bark being firft boiled a few minutes, and Colours,
then adding feven or eight lbs. of m.urio-fulphate of tin, J
with about five pounds of alum. The cloth is to be
dyed in the fame manner as in the procefs for the orange
yellow.
262.. Bright yellows of lefs body are produced by
employing a fmaller proportion of bark, as well as
by diminilhing the quantity of murio-fulphate of tin
and alum. And indeed every variety of lhade of pure
bright yellow may be given by varying the proportions
of the ingredients.
263. Jo produce the lively delicate green lhade, For preen,
which, for certain purpofes, is greatly admired, the ad- ifl* yellow,
dition of tartar, with the other ingredients, only is ne-
cdiary, and the tartar muft be added in different pro¬
portions, according to the lhade which is wanted. For
a full bright yellow, delicately inclining to the greemlh
tinge, it will be proper to employ eight pounds of bark,
fix of murio-fulphate of tin, with fix of alum, and four
of tartar. An additional proportion of alum and tar¬
tar renders the yellow more delicate, and inclines it
more to the green ihade j but when this lively green
lhade is wanted in the greateft perfection, the ingredi¬
ents muff be ui'ed in equal proportions. The delicate
green lemon yellows axe feldom required to have much
fulnefs or body. Ten pounds of bark, therefore, with
an equal quantity of the other ingredients, are fuflicient
to dye three or lour hundred pounds of fluffs *. * Bancroft,
264. To produce the exquifitely delicate and beauti- 33°.
ful pale green ftiades, the lureft method, Dr Bancroft For pale
obferves, is to boil the bark with a fmall proportion of §reen yel"
water, in a feparate tin vefiel for fix or eight minutes,low’
and then to add the murio-fulphate of tin, alum, and
tartar, and to boil them together for about fifteen mi¬
nutes. A fmall quantity of this yellow liquor is then
to be put into a dyeing veffel, which has been previ-
oufly fupplied with water lixlHciently heated. The mix¬
ture being properly itirred, the dyeing procefs is to be
conduced in the ufual way, and the yellow liquor, as
it is wanted, gradually added from the firft veffel. In
this way, the moll delicate fliades of lively green le¬
mon yellows are dyed with eafe and certainty. Weld
is the only dye-fluff from which fimilar ftiades of colour
can be obtained ; but it is four times more expenfive.
The yellows dyed from quercitron bark, Dr Bancroft
adds, with murio-fiilphate of tin and alum as mordants,
do not exceed the expence of one penny for each pound
of fluff; befides a eonfiderablc faving of time, labour,
and fuel f. _ +
265. A greenifti (hade may alfo be produced with- .
out tartar, by fubftituting verdigrife diflolved in vine-
gar, along with the bark 5 but it is neither fo perma-ta^ 0
nent, nor fo bright and delicate, as that produced by
means of tartar. Sulphate of indigo alfo, in very fmall
proportion, communicates a fimilar ftrade, when it is
employed with the bark, murio-fulphate of tin, and
alum j but it is apt to take unequally on the ftuff, and
befides, in the language of the dyers, the colour has a
tendency to cajl ox fly in the finilhing.
266. Small proportions of cochineal employed along cochineal
with the bark and other ingredients, raife the colour to and madder
a beautiful orange, and even to an aurora. Madder employed,
may be alfo employed with the fame view, for it
heightens the yellow obtained from quercitron bark,
although
Chap. I.
Of Simple
Colours.
DYEING.
f Bancroft,
315-
Colours
from quer¬
citron bark
very dur¬
able.
$ Ibid. 334
although the colour thus obtained is inferior in beauty
to that from cochineal. The madder may alfo be em¬
ployed with weld for the fame purpofe f.
267. The colours obtained from quercitron bark,
by the proceffes which we have now deicribed, are ve^
ry durable. They relift the action of the air, of foap,
and of acids. It is by the effefts of alum, but efpeci-
ally of tartar, that thefe colours become fo fixed as to
remain permanent by expofure to the air. It is obfer-
ved of the higheft yellows, even when they approach
to the orange, and which are belt dyed, either with
muriate, or murio-fulphate of tin and bark, that al¬
though they refill the action of foap and acids, they are
apt to lofe their luftre and become brown by the effect
of the fun and air ; but this alfo happens to yellows
dyed with nitre-muriate of tin, both with the bark and
with weld, but in a ftill greater degree with other yel¬
low vegetable colouring matters. In feme of thefe this
defect is lefs eafily obviated by alum and tartar, than it
is in the yellow obtained from weld and quercitron
bark
With weld.
III. Of the Proceffes for Dyeing Silk Yellow.
268. To dye filk a plain yellow colour, the only in¬
gredient which was formerly employed is weld. The
following is the procefs. The filk being previoufly
fcoured in the proportion of 20 lbs. of foap to the too
of Huff, and thin alumed and walhed after the aluming,
or as it is called, refrejhed, the bath is prepared with two
pounds of weld for every pound of filk 5 and, having
boiled for 15 minutes, it is to be palled into a vat
through a fieve or cloth. When the temperature is
fuch as the hand can bear, the filk is introduced, and
turned, until it has acquired a uniform colour. While
this operation is going on, the weld is to be boiled a
fecond time in frelh water •, one half of the firft bath is
taken out, and its place fupplied with a frelh deco£tion.
The temperature of the freih bath may be a little high¬
er than the former, but it is neceffary to guard againft
too great a degree of heat, that the colouring matter
* already fixed may not be diffolved. The fluff is to be
turned as before, and afterwards taken out of the bath.
A quantity of foda is to be diffolved in a part of the fe¬
cond decoction, and a larger or fmaller proportion of
this folution is to be added to the bath, according to
the intenfity of the lhade required. When the filk has
been turned a few times, a Ikain is wrung out, that it
may be examined whether the colour be fufficiently full,
and have the proper golden lhade. To render the co-
For a deep-l°ur deeper, and to give it the gold call, an addition
er colour, of the alkaline folution is to be made to the bath, and
to be repeated till the lhade has acquired fufficient in¬
tenfity. The alkaline folution may alfo be added along
with the fecond decoftion of the weld, obferving the
precaution, that the temperature of the bath be never
too great.
269. To produce other lhades of yellow, having
more of a gold or jonquille colour, a quantity of a-
notta, proportioned to the lhade required, is to be add¬
ed to the bath, along with the alkali. Lighter fhades
of yellow, fuch as pale lemon, or Canary-bird colour,
are obtained, by previoully whitening the filk, and re¬
gulating the proportion of ingredients in the bath by
the lhade required. To communicate a yellow havfflg
ti tinge of green, a little indigo is added to the bath, if
For other
fliades.
435
the filk has not been previoully azured. To prevent Of Simple
the intenfity of the tirade from being too great, the filk ,
may be more llightly alumed than ufual.
270. But, according to Dr Bancroft, the different A. cheaper
lhades of yellow obtained from weld, may be given to procciu
filk with equal facility and beauty, and at a cheaper
rate, by employing quercitron bark as a fubllitute. A
quantity of bark powdered and inclofed in a bag, in
proportion to the llrade of colour wanted, as from one
to two pounds for every twelve pounds of filk, is put
into the dyeing vat while the water is cold. Heat is
then applied; and when it has become rather more than
blood warm, or of the temperature of ioo°, the filk
having previoutly undergone the aluming procefs, is to
be immerfed and dyed in the ufual way. If a deep
Ihade is wanted, a fmall quantity of chalk or pearl-
alhes may be added towards the end of the operation.
To produce a more lively yellow, a fmall proportion of
murio-fdlphate of tin may be employed j but it Ihould
be cautioully ufed, as it is apt to diminifix the luftre of
the filk. To produce fuch a lhade, the proportions of
the ingredients may be four pounds of bark, three of
alum, and two of murio-fulphate of tin. Thefe are to
be boiled with a proper quantity of water for ten or fif¬
teen minutes ; and the temperature of the liquid being
fo much reduced as the hand can bear it, the iilk is im¬
merfed and dyed as ufual, till it has acquired the pro¬
per colour. Care Ihould be taken to keep the liquor
conltantly agitated, that the colouring matter may be
equally diffufed *. * 34S*
271. To dye filk of an aurora or orange colour, af-^or an
ter being properly fcoured, it may be immerfed in an°™r‘se
alkaline folution of anotta, the ftrength of which is to
be regulated by the lhade required j and the tempera¬
ture of the bath Ihould be between tepid and boiling
water. When the defired lhade has been obtained, the
lilks are to be walhed and twice beetled, to free them
from the lixperfluous colouring matter, which would in¬
jure the beauty of the colour. When raw filk is to be
dyed, that which is naturally white Ihould be feledted,
and the bath Ihould be nearly cold •, for otherwife the
alkali, by diffolving the gum of the filk, deftroys its
elafticity. Silk is dyed of an orange flxade with anot¬
ta, but the fi.uffs mult be reddened with vinegar, alum,
or lemon juice. The acid, by faturating the alkali
employed to diffolve the anotta, deftroys the yellow
lhade produced by the alkali, and reftores its natural
colour, which inclines to a red. But although beauti¬
ful colours are obtained by this procefs, they do not
poffefs any great degree of permanency.
272. Several kinds of mulhrooms afford lively and(lye
durable yellow dyes. A bright Ihining dye of this de-*1^1“;rau
feription has been extracted from the boletus hirfutus,
which commonly grows on walnut and apple trees.
The colouring matter is contained both in the tubular
part, and alfo in the parenchyma of the body of the
mulhroom. To extract the colouring matter, it is
pounded in a mortar, and the liquor which is thus ob¬
tained, is boiled for a quarter of an hour in water. An
ounce of liquor is fufficient to communicate colouring
matter to fix pounds of water. After the liquor has
been ftrained, the ftuff to be dyed is immerfed in it,
and boiled for fifteen minutes. When filk is fubjedted
to this procefs, after being dyed, it is made to pafs
through a bath of foft foap, by which it acquires a ffiin-
3 I 2 ing
DYE
* Phil.
Mag. V,
100.
Procefs
with weld.
For a deep¬
er yellow
Of Simple mg golden yellow colour, which has a near refemblance
Colours. to yenow of the lilk employed to imitate embroi-
J “ ' dery in gold. This has been hitherto brought from
China, and bears a very high price, the method of dye¬
ing it being unknown in Europe. AH kinds of Huff
receive this colour, but it is lefs bright on linen and
cotton, and feems to have the ifrongelt affinity for filk.
The ufe of mordants, it is fuppofed, would modify and
improve it greatly *.
IV. OJ the Proce/fts for Dyeing Cotton and Linen
Yellow.
273. The procefs which has been ufually followed
in dyeing cotton and linen yellow, is by fcouring it in
a bath prepared in a ley with the affies of green wood.
It is afterwards waflied, dried, and alumed, with one-
fourth of its weight of alum. After 24 hours, it is ta¬
ken out of the aluming, and dried, but without being
waffied. The cotton is then dyed in a weld bath, in
the proportion of one pound and a quarter of weld for
each pound of cotton, and turned, in the bath till it
has acquired the proper colour. After being taken out
of the bath, it is foaked for an hour and a half in a fo-
lution of blue vitriol (fulphate of copper), in the pro¬
portion of one-fourth of the weight of the cotton, and
then immerfed, without waffiing, for nearly an hour,
in a boiling folution of white foap, after which it is
well waffied and dried.
274. A deeper yellow is communicated to cotton,
by omitting the prooefs of aluming, and employing two
pounds and a half of wTeld for each pound of cotton.
To this is added a dram of verdigrife, mixed with part
of the bath. The cotton is then to be dipped and
worked till the colour become uniform. It is then ta¬
ken out of the bath, that a little folution of foda may
be added, after which it is returned, and kept for fif¬
teen minutes. It is then wrung out and dried.
275. Other ffiades of yellow may be obtained, by
varying the proportion of ingredients. Thus, a lemon
colour is dyed by ufing only one pound of weld for
every pound of cotton, and by diminiffiing the propor¬
tion of verdigrife, or ufing alum as a fubftitute f.
276. But a better method, as it affords more perma¬
nent and more beautiful colours, and at a fmaller ex¬
pence, is recommended by Dr Bancroft. This is by
the ufe of quercitron bark, and the calico printers alu¬
minous mordant, or the fugar of lead. The following
is the procefs which he propofes to employ, for produ¬
cing bright and durable yellow colours. One pound
of fugar of lead, and three pounds of alum, are to be
diffolved in a fufficient quantity of warm water. The
cotton or linen, after being properly rinfed, is to be
foaked in this mixture, heated to the temperature of
too0, for two hours. It is then taken out, moderate¬
ly preffed over a veffel, to prevent the wafte of the alu¬
minous liquor. It is then dried in a ftove heat, and
after being again foaked in the aluminous folution, it is
wrung out and dried a fecond time. Without being
rinfed, it is to be barely wetted with lime water, and
afterwards dried, and if a full, bright, and durable
yellow is wanted, it may be neceffary to foak the Huff
in the diluted aluminous mordant, and after drying, to
wet it a fecond time with lime water. After it has
been foaked for the laft time, it Ihould be well rinfed
in clean water, to feparate the loofe particles of the
and other
lhades.
•}■ Berthollet,
ii. <267.
Cheaper
and 'nore
permanent
colours.
I N G. Part II.
mordant, which might injure the application of the co- Of Simple
louring matter. By the ufe of the lime water, a great- ^ . |t
er proportion of alumina combines with the Huff, be-
fides the addition of a certain portion of lime.
277. In the preparation of the dyeing bath, from 12 Eyeing
to 18 lbs. of powdered quercitron bark are inclofed in a "l
bag, for every too lbs. of the fluff, varying the pro¬
portion according to the intenfity of the ffiade deiired.
The bark is put into the water while it is cold j and
immediately after the fluff is immerfed and agitated or
turned for an hour, or an hour and a half, during
■which the water ffiould be gradually heated, and the
temperature raifed to about 120°. At the end of thb
time the heat is increafed, and the dyeing liquor
brought to a boiling temperature } but at this tempera¬
ture the fluff muft remain in it only for a few’minutes,
becaufe otherwife the yellow affumes a brownifh fliade.
The fluff having thus acquired a fufficient colour, is ta¬
ken out, rinfed and dried.
278. Dr Bancroft obferves, that when the alumi-Advantage
nous mordant is employed, without the addition of wa- of a diluted
ter, one foaking only, and an immerfion in lime water,mor an
may be fufficient; but he thinks that greater advan¬
tage is derived from the application of a more diluted
mordant at two different times, or even by the immer¬
fion of the fluff a greater number of times, alternately
in the diluted aluminous mordant, and lime water, and
drying it after each immerfion. By this treatment he
found, that the colour always acquired more body and
durability.
279. Chaptal has propoled a procefs for commu-j4an^een
nicating to cotton a nankeen yellow, which at the yellow,
fame time that it affords a durable colour, has the
advantage of being cheap and Ample. When cotton is
immerfed in a folution of any fait of iron, it has fo
ftrong an affinity for the oxide, that it decompofes the
fait, combines with the iron, and affumes a yellow co¬
lour. The procefs recommended by Chaptal is the fol¬
lowing. The cotton to be dyed is put into a cold fo¬
lution of copperas (fulphate of iron) of the fpecific gra¬
vity 1.02. It is afterwards wrung out, and immedi¬
ately immerfed in a ley of potaffi of the ipecific gravity
1.01. This ley muft have been previoufly faturated
with a folution of alum. When the fluff has been kept
for four or five hours in this bath, it may be taken out,
waffied and dried. By varying the proportion of ful¬
phate of iron, every variety of ffiade of nankeen yellow
may be obtained.
280. We ffiall lay before our readers another pro-By anothei
cefs for dyeing nankeen colour, which is propofed and procefs.
followed by Mr Brewer, a pradical dyer. It is as
follow’s. • '
“ Mix as much (beep’s dung in clear water as will
make it appear of the colour of grafs 3 and diffolve in
clear water one pound of beft white foap for every ten
pounds of cotton yam, or in that proportion for a gieat¬
er or leffer quantity.
Obforve ;-~*The tubs, boards, and poles, that are
ufed in the following preparations muft be made of
deal 3 the boiling pan of either iron or copper.
Firjl Operation.—“ Pour the foap liquor prepared as
above into the boiling pan 3 ftrain the dung liquor
through a fieve 3 add as much thereof to the foap li¬
quor in the-pan as will be fufficient to boil the yarn,
intended to be dyed, for five hours. When the liquors
are
Chap. I.
dye
Of Simple are well mixed in the pan, enter the yarn, light the
Colours. fire under the pan, and bring the liquor to boil in about
—   two hours, obferving to increafe the heat regularly du-
rina that period. Continue it boiling for three hours j
then take the yarn out of the pan, walh it, wring it,
and hang it in a died on poles to dry. When dry,
take it into a ftove or other room where there is a nre ;
Jet it hang there until it be thoroughly dry.
N. B. “ The cotton yam, when m the Ihed, inoula
not be expofed either to the rain or fun : if it is, it will
be unequally coloured when dyed. _
Second Operation.—" In this operation ufe only one
half of the foap that was ufed in the laft, and as much
dung liquor (drained as before direaed) as will be iut-
ficient to cover the cotton yarn, when m the pan, about
two inches. When thefe liquors are well mixed m the
pan, enter the yarn, light the fire, and bring the li¬
quor to boil in about one hour *, then take the yarn out,
wring it without walhing, and hang it to dry as in the
former operation. . . r .
Third Operation.—“ This operation the fame as the
fecond in every refped.
Fourth Operation.—" For every ten pounds of yarn
make a clear ley from half a pound of pot or pearl-
afhes. Pour the ley into the boilmg-pan, and add as
much clear water as will be diffident to boil the yarn
for two hours } then enter the yarn, light the dre, and
bring it to boil in about an hour. Continue it boning
about an hour, then take the yarn out, wadi it very
well in clear water, wring it, and hang it to dry as in
former operations. , . . c
N. B. “ This operation is to cleanfe the yarn from
any oleaginous matter that may remain in it after boil¬
ing in the foap and dung liquors.
Fifth Operation.—" To every gallon of iron li¬
quor (m) add half a pound of ruddle or red chalk (the
lad the bed) well pulverized.
“ Mix them well together, and let the liquor dand
four hours, in order that the heavy particles may lub-
fide ; then pour the clear liquor into the boilmg-pan,
and bring it to fuch a degree of heat as a perfon can
well bear his hand in it 5 divide the yam into fmall par¬
cels, about five hanks in each j foak each parcel or
handful very well in the above liquor, wring it, and
lay it down on a clean deal board. When all the yam
is handed through the liquor, the lad handful mud be
taken up and foaked in the liquor a fecond time,
and every other handful in fucceffion till the whole is
gone through ; then lay the yarn down m a tub, where¬
in there mud be put a fufficient quantity of ley made
from pot or pearl-affies, as will cover it about fix inch¬
es. Let it lie in this date about two hours, then hand
it over in the ley, wring it, and lay it down on a clear
board. If it does not appear Efficiently deep in co¬
lour, this operation mud be repeated till it has acquired
a fufficient degree of darknefs of colour : this done, it
mud be hung to dry as in former operations.
N. B. “ Any degree of red or yellow hue may be
given to the yarn by increafmg or diminiffiing the
quantity of ruddle or red chalk.
Sixth Operation.—“ For every ten pounds oi yam
I N G. 437
make a ley from half a pound, of pot or pearl-afhcsi OtSonple
pour the clear ley into the boilmg-pan : add a fufficient,
quantity of water thereto that will cover the yam about
four inches-, light the fire, and enter the yam, when
the liquor is a little warm ; obferve to keep it condant-
ly under the liquor for two hours -, increafe the heat re¬
gularly till it come to a feald j then take the yam out,
wadi it, and hang it to dry as in fonner operations
Seventh Operation.—" Make a lour liquor of oil of
vitriol and water : the degree of acidity may be a little
lefs than the juice of lemons j lay the yam m it for a-
bout an hour, then take it out, waih it very well and
wring it; give it a fecond walhing and wringing, and
lay it on a board. ...
N. B. " This operation is to diflblve the metallic
particles’, and remove the ferruginous matter that re¬
mains on the furface of the thread after the fiftn opera-
X°\ighth Operation.—" For every ten pounds of yarn
diffolve one pound of bed white foap in clear water,
and add as much water to this liquor m your boiling-
pan as will be fufficient to boil the yarn for two hours.
When thefe liquors are well mixed, light the lire, en¬
ter the yarn, and bring the liquor to boil in about an
hour. Continue it boiling tlowly an hour ; take it out,
walh it in clear water very well, and hang it to dry as
in former operations : when dry, it is rea y 01 t e
weaver. . , T
N. B. “ It appears to me, from.experiments that I
have made, that lefs than four operations in the prepa¬
ration of the yam will not be fufficient to cleanfe the
pores of the fibres of the cotton, and render the colour # ^
permanent . ,, Ma?. xxii.
281. A method of dyeing cotton and linen a dumbk ^
yellow colour is pradifed in the call. The objed of
this procefs, which is tedious, is to increafe the affinity the eaft#
between the alumina and the fluff, fo that it may ad¬
here with fufficient force to produce a permanent co¬
lour. For this purpofe three mordants am employed :
thefe are oil, tan and alum. The cotton is foaked m
a bath of oil, mixed with a weak folution of loda.
Animal oil, as it is found to anfwer beft, is preferred.
Glue has alfo been tried, and is found to anfwer very
well The foda muff be in the cauftic ftate, for in that
ftate it combines with the oil, and produces on the
cloth an equal abforption. The fluff' is then to be
waffled, and afterwards put into an infufion of nut galls
of the white kind, and the infufion fhould be ufed hot.
The tan combines with the oil, while the gallic acid-
carries off any portion of alkali which may adhere to
the cloth. When the fluff is removed from the bath,
it fhould be quickly dried and too great an excels oi
galls beyond a proper proportion with the oil fhould be
avoided, as it is apt to darken the lhade of colour.
After this preparation the fluff is to be immerfed m a
folution of alum 5 and in confequence of the affinity
which exiffs between tan and alumina, the alum is de-
compofed, and its earth combines with the tan. After
thefe preliminary Heps, the cotton is to be dyed with
quercitron bark, according to the procefs which has
been already deferibed. ni
(m) Iron liquor is what the linen printers ufe.
438
DYE
Of Simple
Colours.
Sect. III. Of Blue.
Indigo
* Lib. xxxv,
introduced
into Eu-'
rope.
Three
fpecies.
Method of
preparing
indigo.
282. The next of the fimple colours Is blue. We
(hall firft treat of the fubftances which are employed in
dyeing blue, and then defcribe the proceffes which are
followed in fixing this colour.
I. Of the Subfances which are employed in Dyeing Blue.
The only fubftances which are ufed in dyeing blue,
are indigo and woad.
283. Indigo was not ufed for the purpofe of dyeing
in Europe till near the middle of the 16th century. A
lubftance is mentioned by Pliny *, w hich was brought
from India, and- termed indicutv, which feems to have
been the fame as the indigo of the modems *, but it does
not appear that either the Greeks or the Romans knew
how to diftblve indigo, or its ufe in dyeing, although it
was applied as a paint. It was, however, long before
known as a dye in India. rIhe firft indigo which was
employed for the purpofe of dyeing by Europeans, was
brought by the I3utch from India. One of the fpecies
of the plant from which it is obtained, was difcovered
by the Portuguefe in Brazil, where it grows fpontane
oudy, as well as in other parts of America. Being
afterwards fuccefsfully cultivated in Mexico, and fome
illands of the Weft Indies, the w'hole of the indigo em¬
ployed in Europe was fupplied from thefe countries.
I he indigo from the Eaft Indies has, however, of late
recovered its charaffer, and is imported into Britain
in confiderable quantities.
284. There ate three fpecies of the indigo plant,
which are ufually cultivated in America. The firft is
the indigofera tinSoma, Linn, which befides being a
fmaller and lefs hardy plant, is inferior to the others
on account of its pulp, but as it yields a greater pro¬
portion, it is generally preferred. The fecond is the
indigofera dfperma, Linn, or Guatimala indigo plant.
I his is a taller and hardier plant, and affords a pulp of
a fuperior quality to the former. The third is the in¬
digofera argentea, Linn, which is the hardieft of the
three fpecies •, yields a pulp of the fineft quality,
though in fmalleft proportion.
285. "When the indigo plant lias arrived at maturi¬
ty, it is cut a few inches above the ground, dif-
pofed in ftrata in a large velfel or fteeper, and being
kept down with boards, is covered with water ; and in
this ftate it is left to ferment till the pulp is extrafted.
The procefs commences by the evolution of heat, and
the emiffion of a great quantity of carbonic acid gas.
When the fermentation has continued for a fufficient
length of time, which is known by the tops becoming
tender and pale, the liquor, which is now of a green
colour, E drawn off into large fiat veffels, called beaters,
where it is agitated with buckets or other convenient
apparatus, till blue fiocculae begin to appear. To pro¬
mote this granulation or feparation of the flocculae it is
ulual to add clear lime water till the liquor in which
they are fufpended become quite colourlefs. The li¬
quor being fufhciently impregnated with the lime w’ater,
is left at reft to allow the particles of the colouring
matter to precipitate •, after which the fupematant li¬
quor is draw n oft, and the fediment colledled into linen
bags, which are fufpended for fome time to let the wa-
;ter drain off. It is then put into fquare boxes, or
I N G. Pait 11,
formed into lumps and dried in the ftiade. The indi- Of Simple
go thus prepared is in a ftate fit for the market. Colours.
286; The indigo which is produced in this opera V'!ri/"~~'
tion differs greatly, not only according to the quality its qua/
of the plant from which it is obtained, but according to ties,
the mode of preparation. But the difference of quantity
feems to depend entirely on the heterogeneous fub¬
ftances with which it is mixed, and on the degree of
confiftence which it has acquired in drying. The light-
eft kind which, is brought from Guatiniala, is called
light indigo ; it is of a fine blue colour, and is the moft
valuable, becaufe it is of the fineft quality. Indigo ex¬
hibits various fhades of colour, which is alfo owing to
the mixture of foreign fubftances. The moft common
(hades are blue, violet, and copper colour.
287. Other plants have alfo been difcovered, which Is obtained
by a procefs fomewhat fimilar, afford indigo, and in fl'om other
particular the nertum tinBorium, or rofe bay, an ac-P'ants*
count of which, with the method of manufa&uring in¬
digo from its leaves, has been given by Dr Roxburgh.
This tree grows in great abundance in different parts
of the Eaft Indies; and plantations of it, raifed from
feeds, have fucceeded well in Bengal. The leaves of
the nerium afford indigo, not only when they are frelh
gathered, but alfo wftien they are nearly dried ; but
they yield the beft indigo after being kept a day or
two. The leaves colle&ed the preceding day are put
into a copper, fo as nearly to fill it without preffing.
The copper is filled with water till within three inches
6f the top 1 and hard fpring wrater, which increafes thd
quantity of indigo, and improves its quality, is pre
ferred. The fire is then applied, and kept up, till the
liquid becomes of a green colour in the veffel. The
leaves then become of a yellowifti colour, and the heat
of the liquor about 150°, or 1600. The leaves ftiould
be conftantiy agitated, that they may be equally heat¬
ed, as well as to promote the operation, by the expul-
fion of the carbonic acid gas. When the procefs exhi¬
bits the above appearances, the liquor is to be drawn
off, puffed through a hair-cloth, and agitated while hot
in the ufual wny, till granulation takes place, or the
appearance of blue flakes is obferved. About fs- Part
of ftrong lime water is then added, to promote the pre¬
cipitation of the indigo, and the remaining part of the
procefs is fimilar to that deferibed above, for the ma-
tiufadfure of indigo from indigofera f. , „ .
288. The objedl of the proceffes which are followed *
in the manufaflure of indigo, is to extract from the Mature of
plants which yield it, a green fubftance, which is folu-tbe fub-
ble in water. This fubftance, which has a ftreng af- (lances ex*
finity for oxygen, gradually attracts it from the air, be- traifteih
comes of a blue colour, and is then infoluble in water.
This abforption is greatly promoted by agitation, for
then a greater furface is expofed to the adtion of the
air •, and the lime water, by combining with carbonic
acid, which exifts in the green matter, alfo promotes
the feparation of the indigo.
289. Indigo is infoluble in water, alcohol, ether, pr0pfrt[ef
and oils, and the only acids w hich produce any effedt 0f indigo,
upon it, are the fulphuric and nitric. By the latter
it is foon changed to a dirty white colour, and is at laft
entirely decompofed. When the acid is concentrated,
the indigo is inflamed ; but when it is diluted, the in¬
digo becomes brown, and cryftals like thofe of oxalic
and
Chap. I,
DYE
Hates.
Ot Simple and tartarous acids make tkeir appearance j and when
, Co^ouls- the acid and cryflals are waflied off, there remains be¬
hind a kind of rennous matter. Sulphuric acid in the
concentrated ffate diffolves indigo, with the evolution
of a great deal of heat. The folution is opaque and
black, but when diluted with water, it changes to a
deep blue colour. Dr Bancroft has denominated this
folution filpbcte of indigo, which has been long known
by the name of liquid blue. The fixed alkalies in the
ffate of carbonate precipitate ilowly from fulphate of
indigo, a blue coloured powder, which has the proper¬
ties of indigo, but is found to be foluble in moft of the
acids and alkalies. Pure alkalies deftroy the colour
of fulphate of indigo, as well as that which is precipi¬
tated.
Is employ- 290. Indigo is employed in dyeing, both in the ftate
ed in dye- of liquid blue, or fulphate of indigo, from which is ob-
jng in two tained the beautiful colour called Saxon blue ; and al-
fo in the ilate of iimple indigo, or the indigo of com¬
merce. In dyeing with indigo, it muff be reduced to
the ffate of the green matter as it exilfs in the plants,
or when it is firit extra&ed from them. It muff be de¬
prived of the oxygen, to the combination of which the
blue colour is owing, bn this ftate it becomes foluble
in water by means of the alkalies. To effect this re¬
paration of the oxygen, the indigo muff be mixed with
a folution of fome fubftance which has a ftronger affi¬
nity for oxygen than the green matter of indigo. Such
fubffances are green oxide of iron and metallic fulphu-
rets. Lime, green fulphate of iron, and indigo, are
mixed together in w^ater, and during this mixture the
indigo is deprived of its blue colour, becomes green,
and is diffolved, while the green oxide of iron is con¬
verted into the red oxide. In this procefs, part of the
lime decompofes the fulphate of iron, and as the green
oxide is fet at liberty, it attracts oxygen from the in¬
digo, and reduces it to the ftate of green matter, which
is immediately diffolved by the attion of the reft of the
lime. Indigo is alfo deprived of its oxygen, and pre¬
pared for dyeing,-by another procefs. Some vegetable
matter is added to the indigo mixed with water, with
the view' of exciting fermentation $ and quicklime or an
alkali is added to the folution, that the indigo, as it is
converted into the green matter, may be diffolved.
Woad. 291. Another plant, known under the name of pad el
or luoad, (tfatn tindiorw), is employed for dyeing blue.
Another fpecies (ifatit lufitanica'), which is a imaller
plant, is alfo employed in dyeing. The ifatis tinRorm
is cultivated in France and in England. When the
plant has reached maturity, it is cut down, waffied in a
river, and fpeedily dried in the fun. It is then ground
in a mill, and reduced to a patte, which is formed into
heaps, covered up to protetl them from the rain, and
at the end of a fortnight the heap is opened, to mix
the whole well together. It is afterwards formed into
round balls, which are expofed to the wind and fun,
that the moifture may be feparated. The balls are
heaped upon one another, become gradually hot, - and
exhale the fmell of ammonia. To promote the fer¬
mentation, which is ftronger in proportion to the quantity
heaped up, and the temperature of the feafon, the
heap is to be fprinkled with water till it falls down in
the ftate of coarfe powder, in which ftate it appears in
commerce. The blue colour obtained from woad is
very permanent, but has little luftre. But its colour
I N G. 439
is not only inferior in beauty to that obtained from in- Of Simple
digoj it affords alfo a fmaller proportion of colouring
matter, fo that iince the dii’covery of indigo, the ufe of
w oad has diminilhed.
Colours.
II. Of the Procejjes for Dyeing Wool Blue.
292. The preparation for dyeing blue is made in a Preparation
large wooden veffel or vat, which fnould be fo conftru£i-of thc
ed„as to retain the heat, which is a matter of confiderable
importance in the procefs. The vat is therefore fet up
in a feparate place from the coppers, and is funk fo far
in the ground as to be only breaft-high above it. Be¬
fore the introduftion of indigo, blue was dyed with
woad, which affords a permanent, but not a deep co .
lour ; but a very rich blue is obtained by mixing indi¬
go with the woad, and thefe are almoft the only iub-
ftances wffiich are now employed for dyeing woollen
ftuffs. The proportions of thefe fubftances are varied
by different dyers, and according to the ffiade which is
required. The following is the account of the pre¬
paration of a vat, as it is given by Quatremere. Into
a vat of about feven and a half feet deep, and five and a
half in diameter, are thrown two balls of paftel or woad,
wffiich are previoufly broken, and together amount to
about 400 pounds weight; 30 pounds of w'eld are boil¬
ed in a copper for three hours, in a fufficient quantity
of water, to fill the vat. To this decodtion are added
20 pounds of madder, and a balket full of bran. The
boiling is then continued half an hour longer. This
bath is cooled with 20 buckets of water, and after it is
fettled, and the w^eld taken out, it is poured into the
vat, which muft be ftirred with a rake all thp time
that it is running in, and for 15 minutes longer. The
vat is then covered up very hot, and allowed to ftand
for fix hours, wffien it is uncovered, and raked again
for 30 minutes. 1 he fame operation muft be repeated
every three hours. When the appearance of blue
ftreaks is perceived on the furface of the vat, eight or
nine pounds of quicklime are added ; the colour then
becomes of a deeper blue, and the vat exhales more
pungent vapours. Immediately after the lime, or along
with it, the indigo, which has been previoully ground
in a mill, with the fmalleft poffible quantity of water,
is put into the vat. The quantity is to be regulated
by the inteafity of the fhade required. From ten to
thirty pounds may be put into a vat fueh as w-e have
now defcribed. If on ftriking the vat with the rake, a
fine blue fcum arifes, no other previous preparation is
required than to ftir it with the rake twice in the fpace
of fix hours, to mix the ingredients completely. Great
care ihould be taken not to expofe the vat to the air,
except during the time of ftirring it. When that ope¬
ration is finiffied, it is covered with a wmoden lid, on
which are fpread thick cloths, to retain the heat as
much as poffible } but after all thefe precautions, at the
end of eight or ten days it is greatly diminiftied, and is
at laft entirely diflipated, fo that the liquor muft be
again heated, by pouring the greater part of the liquor
of the vat into a copper under which a large fire is
made. When the liquor has acquired a fufficient
temperature, it is returned into the vat, and carefully
covered up.
292. Vats of this defcription are fometimes liable to Accident?
accidents. A vat is faid to be repelled, when havingto which
previoully afforded fine {hades of blue, it appears “
black. -
440
DYE
Means of
obviating
them.
and re¬
medying
putrefaC'
tion.
Of Simple black, without any blue ftreaks ; and if it be ftirred,
Colours. black colour becomes deeper the vat at the lame
   time exhales, inftead of a fweetilh fmell, a pungent
odour : and the fluff dyed in a vat in this ftate, comes
out of a dirty gray colour. Tihefe effects are afcnbed
to an excefs of lime.
294. Different means are employed to recover a re¬
pelled vat. Some are fatisfied with merely reheating
it: -while others add tartar, bran, urine, or madder.
Hellot recommends bran and madder as the belt re¬
medy. If the excefs of lime be not very great, it is
fufficient to leave it at reft five or fix hours, putting m
a quantity of bran and three or four pounds of madder,
which are to be fprinkled on the furface, and then it
is to be covered up, and after a certain interval, to
be tried again. But if the vat has been (o far repelled
as to afford a blue only when it is cold, it mull be left
at reft to recover, and fometimes mull remain whole
days without being ftirred with the rake. When it be¬
gins to afford a tolerable pattern, the bath muff be re.
heated. In general, this revives the fermentation. I he
addition of bran or madder, or a balket or two of trelh
woad, pToduces the fame effedl. .
295. This vat fometimes runs into the putrefactive
procefs. W hen this happens, the colour of the vat be¬
comes reddilb, the pafte rifes from the bottom, and a
fetid fmell is exhaled. This accident is owing to a de.
ficiency of lime, and it muff be correaed by adding
a frelh quantity. The vat is then to be raked j alter
two hours more lime is added, and the procels of rak¬
ing again performed. Thefe operations are to be re¬
peated till the vat is recovered.
Precautions *96. Nothing requires more attention m treating a
in the ufe vat of this kind, than the diftnbution of the lime, the
«f lime. principal ufe of which is to moderate the tendency to
putrefadion, and to limit the fermentation to that de¬
gree which is neceffary to deprive the indigo of its oxy¬
gen. If too much lime be added, the neceilary fer¬
mentation is retarded, and if there be too little, the
putrefaclive procefs commences.
2n-. Two hours previous to the dyeing operation,
the vat fhould be raked ; and to prevent the fluff
coming in contaft with the fediment, which would pro-
duceTnequalities in the colour, a crofs of wood is intro¬
duced. The ftuff is then to be completely wetted with
pure water a little heated 5 and being wrung out, it is
dipped into the vat, where it is moved about lor a
longer or a fhorter time, according to the depth of
fhade required. During this operation it is taken out
occafionally, to be expofed to the air, the adion a.,
which is neceffary to change the green colour of the
bath into a blue. Stuft's dyed blue in this manner muft
be carefully wafhed, to carry off the loofe particles of
colouring matter *, and when the ihade of bme is deep,
they ought even to be cleanfed, by fulling with foap.
This operation does not alter the colour. _
298. When a vat is prepared entirely of indigo,
without paftel or woad, it is called an indigo vat. The
veffel employed for this purpole is of copper, into which
water is poured according to its capacity, to the amount
of 40 buckets, in which have been boiled fix pounds of
potafh, twelve ounces of madder, and fix pounds of
bran. ’ Six pounds of indigo ground in water are then
put in, and after it has been carefully raked, the vat is
to- be covered. A flow fire is to be kept up, and
Dyeing
procefs.
tndigo Vat.
I N G. ft-
twelve hours after it is filed, it is to he raked a foeond Of Simple
time. This operation is to be repeated every twelve, ,
hours, till it come to a blue colour, which will gene¬
rally be the cafe in about 48 hours. If the bath is pro¬
perly managed, it will be of a fine green, exhibiting
on the furface coppery fcales, and a blue ?r
flower. In this vat the indigo is rendered foluble m
water, by means of the alkali inftead of lime. I he
dyeing operation is to be condudted in the fame man¬
ner as the preceding.   . „ „ ,
299. Two vats have been defcribed by.Hellot, mHelots
which the indigo is diffolved by means of urine. Mad¬
der is added to it, and in the one vinegar, in the other
alum and tartar, of each a quantity equal in. weight
to that of the indigo. The proportion of urine muft
be confiderable. In confidering the theory of this pro¬
cefs, it feems probable that the indigo, deprived of its
oxygen by the urine and madder during the fermenta¬
tion, is diffolved by the ammonia which is formed in
the urine. When the folution of alum and tartar is
added, an effervefcence, which Hellot obferved, is
produced. This, it is probable, has a tendency to re¬
tard or flop the putrefaaion. But in vats of this de-
fcription, operations on a large fcale cannot be carried
on} they feem only adapted for finall dye-houfes.
III. 0/ the Procejfes for Dyeing Silk Blue.
300. Silk is dyed blue with indigo alone, without with indi*
any proportion of wroad. The proportion of indigo go.
mentioned in the preparation of the indigo vat, and
fometimes a larger proportion, is employed, with fix
pounds of bran, and about twelve ounces of madder.
According to Macquer, half n pound of madder for
each pound of potafti, renders the vat greener, and
produces a more fixed colour in the filk. When the
vat is come to, it ftiould be refrefoed with two pounds
of potafti, and three or four ounces of madder •, and
after being raked in the courfe of four hours, it is fit
for dyeing. The temperature ftiould be fo moderated,
that the hand may be held in it without, uneafinefs.
201 The filk, after being boiled with foap, in the Preparation
proportion of 30 pounds of foap to 100 of filk, and of the filk.
well cleaned by repeated beetlings in a ilreatn of water,
muft be dyed in finall portions, becaufe it is apt to take
on an uneven colour. When it has been turned once
or oftener in the bath, it is wrung out, and expofed to
the air, that the green colour may change to a blue.
When the change is complete, It is thrown into clear
water, and afterwards wrung out. Silk dyed blue
fhould be fpeedily dried. In damp weather and m win¬
ter, it is neceffary to conduct the drying in a chamber
heated by a ftove. The filk ihould be hung on a
frame kept conftantly in motion. To dye light lhades,
fonie dyers •employ vats that are fomewhat exhaufted j
but it ought to be obferved, that the colour thus ob¬
tained is Ids beautiful and lefs permanent, than when
frefti vats, containing a fmaller quantity of indigo, are
employed. , , , 1 ,, ,
302. Some addition is required to be made to the For Turkef
indigo, to give filk a deep blue. A previous prepara-blue,
tion is neceffary, by giving it another colour or ground.
For the Turkey blue, which is the deepeft, a itrong
bath of archil is firft prepared. Cochineal is alfo fome¬
times ufed, inftead of archil, for the ground, to ren¬
der the colour more permanent. A blue is given to
iuk
Chap. I. . D Y E
Of Simple filk by means of veroligrife and logwood, but it poffeffes
Colours, little durability. It might be rendered more perma-
* «* nent, by giving it a lighter (hade in this bath, then
dipping it in a bath of archil, and finally in the indigo
vat.
Dyeing raw 303. When raw filk is to be dyed blue, inch as is
lllk* naturally white Ihould be felected. Being previoufly
foaked in water, it is put into the bath in feparate
hanks, as already dire&ed for fcoured filks •, and as
raw' filk is found to combine more readily with the co¬
louring matter, the fcoured filk, when it can be con¬
veniently done, ihould be firll put into the bath, df
archil, or any of the other ingredients which have
Been already mentioned, are required, to give more in-
tenlity to the colour, the mode of application is the
fame as that directed for fcoured filk.
IV. Of the Procejfes for Dyeing Cotton and Linen Blue.
Preparation 304. For dyeing cotton and linen blue, Pileur
of the vat. d’Apligny recommends a vat containing about 120
gallons. From fix to eight pounds of indigo reduced
to powder, are boiled in a ley drawm off from a quan¬
tity of lime, equal in weight to the indigo, and a
quantity of potafh double its weight. During the
boiling, which is to be continued till the indigo is
completely penetrated with the ley, the folution mull
be conftantly ftirred, to prevent the indigo from being
iniured, by adhering to the bottom of the veflel.
305. During this procefs, another quantity of quick¬
lime, equal in weight to the indigo, is to be ilaked.
Twenty quarts of warm water are added, in wdiich is
to be dilfolved a quantity of copperas (fulphate of iron)
equal to twdce the weight of the lime. The folution
being completed, it is poured into the vat, which is
previoufly half filled with water. To this the folution
of indigo is added, with that part of the ley which
was not employed in the boiling. The vat mull now
be filled up to within two or three inches of the top.
It mull be raked twice or thrice a day till it is com¬
pletely prepared, which is generally the cafe in 48
hours, and fometimes fooner, as it depends on the tem¬
perature of the atmofphere. A fmall proportion of
bran, madder, and woad, is recommended by fome, to
be added to fuch a vat as we have now defcribed.
A Ampler procefs which is follow ed at Rouen, and
procefs. defcribed by Quatremere, is fimpler. The vats, which
are conitrufted of a kind of flint, are coated within
and without with fine cement, and are arranged in one
or more parallel lines. Each vat contains four hogs-
Iteads of w ater. The indigo, to the amount of 18 or
20 pounds, being macerated for a w'eek in a caullic
ley, llrong enough to bear an egg, is ground in a
mill} three bogheads and a half of water are put in¬
to the vat, and afterwards 20 pounds of lime. The
lime being thoroughly flaked, the vat is raked, and 36
pounds of copperas are added •, and when the folution
is complete, the ground indigo is poured in through a
fieve. It is raked feven or eight times the fame day,
and after being left at reft for 36 hours, it is in a ftate
fit for dyeing.
Procefs on a 3°7. In extenfive manufactories, it is neceflary to
larger fcale. have vats fet at diflerent times. In conducing the pro¬
cefs of dyeing, the fluffs are firft dipped in the moil ex-
haufted vat, and then regularly proceeding from the
weakeft to the ftrongeft, if they have not previoufly at-
Vol. VII. Part II.
TNG. 441
tained the defired fliade. The fluffs ihould remain in Of‘jimple
the bath only about five or fix minutes, for in that time . Col°urs- ,
they combine with all the colouring matter they can
take up. After the fluffs have been dipped in a vat,
it ftiould not be ufed again, till it has been raked, and
flood at leaft 24 hours, unlefs it has been lately fet,
when a Ihorter period is fufticient.
308. After the fluffs have been dipped three or four
times in a vat, it begins to change. It becomes black,
and no blue or copper-coloured ftreaks are feen on the
furface after raking it. It muft then be renewed, by
adding four libs, of copperas, with two of quicklime,
after which it mult be raked twice. In this way .a vat
maybe renewed three or four timesj but the additional
quantity of ingredients muft be diminilhed, as the
ftrength of the vat is exhaufted *. * BertlolUt,
309. A vat which is ftill more Ample, and more ea- 9°-
fily prepared, has been recommended by Bergman. <p°C<LSa°
The proportion of the ingredients wdflch he has direft- ^
ed to be employed, is the following. To three
drachms of indigo reduced to powder, three drachms
of copperas, and three of lime, add two pints of water.
Let it be well raked, and in the courfe of a few hours
it will be in a proper ftate for dyeing.
31 o. Hauffman employs flill a fmaller proportion of Hauffmairs.
indigo. For 3000 libs, of w ater he takes 36 libs, of
quicklime flaked in 200 libs, of water, with which the
indigo in the proportion of from 1 o to 20 libs, well ground, y
is to be mixed. He then diffolves 30 libs, of copperas
in 120 libs, of hot waiter. The whole being left at reft
for fifteen minutes, the vat is filled, and gently and
conftantly ftirred. When a deeper fliade is wanted,
and particularly when linen is to be dyed, the propor¬
tion of indigo Ihould be greater *, but the lhade depends
very much on the time the fluffs remain in the vat, and
the times it has been ufed. When the vat becomes
turbid, the pvocefs of dyeing muft be interrupted, till
it has been again raked, and the fupematant liquor be¬
come tranfparent. If the effefts of the lime fail, a new
quantity frefti flaked, muft be added j and if the iron
ceafe to produce the effedl on the indigo, a new por¬
tion muft be alfo added, obferving the precaution to have
a greater quantity of lime than what is neceffary to fatu-
rate the fulphuric acid. When the indigo feems to be ex¬
haufted, freth portions ground in water are alfo to be ad¬
ded *, the vat is to be raked feveral times, and allow'ed to
fettle, after which it is again fit for ufe. In this way Mr
Haulfman informs us he preferved a vat for the fpace of
two years ; and had it not been for the accumulation
of fediment, which prevented the ftufts from being im-
merfed to a fufficient depth, it might have been conti¬
nued in ufe for a much longer time. It is worth while
to add, that Mr Hauffman found, that a pattern of cloth
dipped in water, acidulated with fulphuric acid, imme¬
diately after it was taken out of the bath, became of a
much deeper blue than a fimilar pattern expofed to the
air, or another dipped in river water.
311. Another convenient and expeditious vat is men¬
tioned by Bergman, and defcribed by Scheffer. Indi¬
go reduced to fine powder, in the proportion of three
drachms to a quart, is added to the Itrong ley of the
foap-boiler. After a few minutes, when the colouring
matter is w;ell penetrated by the ley, fix drachms of
powdered orpiment are to be added. In a few minutes
after the bath has been w^ell raked, it becomes green,
3 K and
442
Of Simple
Colours.
Difcovery
of Saxon
blue.
DYE
and the blue ftreaks appear on the furface. Heat
is to be applied j when the operation of dyeing may
commence.
312. The preparation employed for printing cottons
is iimilar to the above bath, excepting in the propor¬
tions of orpiment and indigo, which are greater in the
former j but thefe proportions are very different in dif¬
ferent manufactories.
313. Saxon Blue.—The colour which is obtained by
dyeing with a folution of indigo in fulphuric acid is
known under the name of Saxon blue, becaufe the pro-
cefs was fir ft carried on at Grolfenhayn in Saxony, by
Counfellor Barth, who made the difcovery about the
year 1740. This difcovery was for fome time kept
fecret, and the method feeras to have been originally
very complicated. Alumina, antimony, and fame other
fubftances, w'ere previouily added to the fulphuric acid.
Thefe, however, are now omitted, and the indigo alone
is diffolved in. the acid.
Preparation 314. From a great number of experiments which
ofthe dye. were made on this procefs by Bergman, he concluded,
that in thofe cafes where the fulphate of indigo afford¬
ed only a fading colour, the acid employed had been
too weak. Quatremere obferves that, among feveral
proceffes for dyeing with fulphate of indigo, he difco-
vered only two, in which the fluffs were completely
penetrated with colouring matter. To effeCf this, he
employed an alkali, in the proportion of one ounce to
an ounce of indigo, and fix ounces of fulphuric acid.
With thefe proportions of the ingredients he obtained
a deep vivid blue, equally intenfe through every part
of the fluff. Poerner, who has paid great attention to
this preparation, alfo employs an alkali, by means of
which a more pleafing colour, which penetrates deeper,
is produced. The proportions which he recommends
are four parts of fulphuric acid to one of indigo, d he
indigo is firft reduced to a fine powder, and the luiphu-
ric acid, in the concentrated flate, is poured upon it.
The mixture is ftirred for fome time, and having flood
twenty-four hours, one part of dry potafti in fine pow¬
der, is added } and after the whole is again ftirred, it
remains for twenty-four hours longer. It is then to be
diluted with eight times its weight of rvater, which
muft be gradually added, or a greater or lefs proportion
as may be wanted.
Dr Bancroft feems to be of opinion, that a more du¬
rable blue may be obtained by diluting the acid with
an equal quantity of w'ater, when the indigo is put in,
and allowing the mixture to remain forty-eight hours ;
for he thinks by this flower and more moderate action,
the bafis of the indigo is lefs injured. Inftead of the
potalh employed by’Poerner, Dr Bancroft ufes chalk ;
and even in inch a quantity as to faturate the acid. In
this cafe the indigo is precipitated along with the
chalk •, and, when collected into a folid mafs, commu¬
nicates a blue colour to wool, but more flowly than by
tl}e common method, in which the combination is very
rapid and the dyeing unequal. This inconvenience he
thinks might be obviated by the ufe of chalk *.
315. To produce a Saxon blue colour on wmollen
fluffs, they are prepared with alum and tartar. And
in proportion to the ftiade required, the quantity of fo¬
lution of indigo put into the bath muft be regulated.
When a deep ihade of Saxon blue is wanted, the fluff
muft be paffed different times through veffels containing
By Ban
croft.
* Phil of
Perm. Col.
X33.
For woollen;
fluffs.
I N G. Partll.
fuch a quantity of colouring matter as is fufficient to Of Simple
give light colours. In this w'ay, by repeated applica- Colours,
tions, the colour becomes more uniform. v ~
316. The fulphate of indigo is alfo employed to dyeForfilk.
filk. For this purpofe attempts have been made to
unite the advantages of the indigo vat and its folu¬
tion in fulphuric acid. A procefs of this kind is
greatly recommended by Guhliche, which produces
beautiful colour*, and is at the fame time cheap and
convenient. The bath is compofed of one pound of
indigo, three pounds of quicklime, three of copperas,
and one and a half of orpiment. The indigo is firft to
be carefully ground and mixed with water, put into a
wooden vat, and diluted with water, according to ther
ftiade of colour wanted. The lime is then to be add¬
ed, and the mixture being well ftirred, it is covered
up, and allowed to remain at reft for fome hours. Af¬
ter this the copperas in the ftate of powder is added,
the whole well ftirred, and the vat covered up. And
laftly, at the end of fome hours, the orpiment reduced to
powder is thrown in, and the whole left at reft for feveral
hours. The mixture is afterwards to be ftirred, and
then left to fettle, till the liquor becomes clear ; wftien
the blue ftreaks or flower which covers it is removed,
and the filk previoufly dipped in warm w^ater, is to
be dyed hank by hank. When it is removed from
the bath, it is to be walhed in a ftream of water, and
dried.
317. This procefs is recommended as the means of
obviating a greenilh call, which is fometimes obi’erved
in Saxon blue, and which is fuppofed to be owing to
fome change in the particles of indigo, by means of the
fulphuric acid.
318. The colour denominated EngHJh blue is pro-Englifh
duced by means of the fulphate of indigo. To give blue,
filk this colour, it is firft to be dyed a light blue 5 and,
when taken out of this bath, it is dipped in hot water,
walhed in a ftreamj and left in a bath compofed of
the fulphate of indigo, to which a little of the folution
of tin has been added, until the proper (hade is obtain¬
ed, or the bath is exhaufted. Previous to its being
put into this bath, it may be dipped in a folution of
alum, in which it ihould only remain a very ihovt time.
Silk, which has been dyed according to this procefs,
is free from the reddilh thade which it derives from the
blue vat, as well as from the greenilh call of the Saxon
blue *. * Berth ellli)
319. The fulphate of indigo has been hitherto only11* 3IP-
applied for the purpofe of dyeing wool and filk. The
affinity of indigo for vegetable fubftances is not fuffici-
ently ftrong to effedft the decompofition of the fulphate.
It cannot, therefore, be employed with advantage in
dyeing cotton and linen.
320. Attempts have been made to dye with Pruffian Dyeing
blue. The procefs which was followed by Macquer is with prnfc.
the following. He ibaked wool, filk, cotton, andfian blue*
thread, in a folution of alum and fulphate of iron, and
afterwards in an alkaline folution, which was partly fa-
turated with pruffic acid. He then immerfed the fluffs
in water, acidulated with fulphuric acid, for the pur¬
pofe of diffolving that part of the oxide of iron which
remained uncombined with the pruffic acid, and which
the uncombined alkali- had precipitated. By fucceffive
repetitions of thefe immerfions he obtained a fine blue,,
but very unequal. Berthollet juftly remarks on this
experiment.
Ch&p* I*
DYE
Another
procefs.
De la Pla
tiere’s.’
Of Simple experiment, that an alkali faturated with pruffic acid
Colours, fljould be employed, or lime water or magnelia, both ot
 ’ which have the property of combining with that acid.
In a fecond experiment Macquer boiled the fluffs m a
folution of tartar and alum, and then palled them
through a bath which contained the pruffian blue mere¬
ly diffufed in it. Idle colour was faint, and could not
be made deeper j but it was equal, and foft to the touch.
021. In the procefs propofed by Abbe Menon for
thread and cotton, they are firft dyed black, and foaked
for a few minutes in prufliate of alkali, and afterwards
boiled in a folution of alum. In this way they ac¬
quired a deep blue. When a lighter blue is wanted,
the fluffs mull be paffed through a weak acid.
3 22. Similar to the fecond experiment of Macquer is
the procefs of Roland de la Platiere. He takes pruf¬
fian blue in the proportion of a pound to a piece of lluft,
powdered, and paffed through a very fine fieve, and
adds muriatic acid till it is reduced to the confiftence ot
fvrup. It is to be conftantly ffirred for about hait an
hour * while it ferments. It is then well diluted, and
ffirred every hour for a day, till the fermentation ceafes.
The particles are thus in a ftate of minute diviiion.
Seven or eight buckets of water for one piece of velvet,
are put into a trough-, then add the mixture, which has
been previouily well diluted in a feparate veflel, and
poured into the bath through a very fine fieve. When the
piece is placed on the winch, over the trough, let the
bath be brifkly flirred, and the piece fpeedily let down-,
and the fame operation mull be continued as quickly as
poffibk for feveral hours. This colour requires great
management, for as the particles of the pruffian hme
are only in a flate of minute diviiion, and heavy, they
are quickly depofited on the fluff. Hence the. colour
appears very unequal and in patches, even with the
utmofl care } and nothing can be done to avoid it, but
repeating the operations again and again. I he fluff
fliould be put into the baths thoroughly wet, for when
it is dry, it penetrates with difficulty, and is always un¬
equal. Between the dryings the fluff is always to be
waffled and beetled, excepting the lall time, when it
is not waffled, but dried in the open air, either in ti.e
fun or in the fhade } obferving howrever, that it lie w'ell
ilretched. This beautiful colour is not changed by the
air it refills the a£lion of acids, and is little altered
by boiling wdth alum } but it is loon tamiihed by fiiclion,
or particles of dull that adhere to it. It is fcarcely ne-
ceffary to add, that it is inflantly decompofed by alka¬
line liquors. Guhliche employs a folution of tin hi ni-
tro-muriatic acid, as a fubllitute for muriatic acid, in
* Btrtlolht, the procefs of dyeing with pruffian blue *.
ii. 20. 323. Dr Bancroft made a number of experiments m
.Bancroft s. dyeing botb vegetable and mineral matters, witli pruf¬
fian blue, and uarticularly with the view of obviating
fian blue, and particularly with the view' of obviating
the difficulties which had occurred to others in the ufe
of it. He boiled up copperas wdth quercitron bark,
fuftic, and logwood, feparately, in what he thought the
bell proportions and in each of thefe mixtures he dyed
a piece of woollen cloth by boiling it for 10 or 15 mi¬
nutes. The fluffs were afterwards feparately immerfed
in warm diluted prufliate of potafh neutralized by lul-
-phuric acid. They acquired an equal and beautiful
blue. This however, was not the uniform refult 5 for
when too much copper as w7as employed in dyeing with
quercitron bark, there wTas an excels of oxide oi iron,
I N G. 443
which combining with the fibres of the woo., gat - tk<2
pruffian blue a greenifh tinge •, but this he round could ^ >
be remedied, by pafiing the cloth throug w^rcn wa
ter, flightly acidulated with muriatic acid. I he prui-
fian colouring matter, Dr Bancroft obferves, muff al¬
ways be applied in a moderate beat, otherwise it will
be precipitated by the fulphuric acid, and rendered
unfit for this purpofe, till it is again diffolved by pot¬
afh, lime, or fonte other fubiiance.
324. He then tried to fix pruffian blue by means ot
the aluminous mordant, but at the. end of 15 nn~
nutes, after being immeried in a folution of printiate ot
potafh, it had acquired no colour. The addition ot a
{mail proportion of a folution of iron in muriatic acid,
communicated a blue colour. All parts of the cloth,
as well as thofe to which the mordant had been applie ,
received the colour. The cloth being wafhed with
foap, the whole of the colour was difeharged, except¬
ing where it had been impregnated with alumina, and
even there it had become fainter. A piece of the-ame
cotton w-as immerfed in a folution of ammonia (vo-atue
alkali) ; the pale blue was greatly heightened. Ano¬
ther piece was put into water flightly tin dural with a
folution of copper in ammonia, i he blue colour be¬
came fuddenly of an intenfely deep garter-blue or vio¬
let, and it refilled the adion of foap. Into water mix¬
ed with a little of a folution of muriate of copper, he
put another piece of the fame cotton, and it foon be¬
came of a deeper blue, without any of the purple or
violet fhade. This refiited the adion of foap, and af¬
ter long expofure to the weather, the colour, was little
diminifhed j and when the colour remained in any de¬
gree weakened, inimerfion in water iligntly acidulated
with fulphuric acid, completely rellored it. I1 tom thefe
fads it would appear to be advantageous to prepat e
woollens by the ufual boiling with alum, or a turn and
tartar, before they are dyed with copperas and querci¬
tron bark, fuffic or logwood, for a pruffian blue ; but
a greater proportion of fulphuric acid, in the piuuiate
of potafh or lime, that tlje excels of acid may difeharge
the vegetable colouring matters becomes neceffary *. * Phil.
3 25. Dr Bancroft afterwards tried pieces of filk and 0 ’
cotton in tbe diluted pruffiates of potafh, foda., .lime, and
&c. with folutions of mofl of the metals in differentcotton.
acids and alkalies ; and from the different metallic fo¬
lutions he obtained a very full,.lively colour, which he
calls the red copper colour ; from the different folutions
of copper in fulphuric, nitric, muriatic, and acetic
acids j the fame effed fucceeded well from a folution in
ammonia. He obtained alfo tbe fame colour iiom the
nitrates of filver and of cobalt. The pruffian colouring
matter fixed by thefe metallic mordants refilled the ac¬
tion of acids, wafhings with foap, and expofure to the
weather for the greateft length of time; but in all thefe
cafes there muff be a double application. The pruffian
colouring matter muff firft be applied to the linen, cot¬
ton or filk, which muff be afterwards allowed to dry.
It muff then be immerfed in the metallic folution, or
the metallic folution muff be applied firil, and then the
folution of prufliate of potafh, foda, lirne, &.c.
Sect. IV. Of Dyeing Black.
The next of the iimple colours is black, of whicli
we fliall treat as in the former fedions firlt deferibing
the fubftances which are employed, and then giving an
3 K 2 account
444
DYE
Of Simple account of the procefles which are followed in dyeinsr
Colours. ^ . o
dilferent Huffs of a black colour.
I. Of the Sulfianccs employed in Dyeing Black.
Juices of
plants.
Tan, See.
Mordants
neceffary
for Hack.
326. There are few fubflances which have the pro¬
perty of producing a permanent black colour, without
any addition. The juice of fome plants produces this
effe£l on cotton and linen. A black colour is obtained
from the juice of the cajhe’w nut, which will notwafh out,
and even refills theprocefs of boiling with foapor alkalies.
The cafhew nut of India is employed for marking lin¬
en. That of the Well Indies (^anacardiitm occidentale,
Lin.J) alfo yields a permanent dye, but the colour has
a brownifh fhade. The juice of fome other plants, as
that of the toxicodendron, or floes, affords a durable
blueifh black colour •, but thefe fubltances cannot be
obtained in fufficient quantity, even if they afforded
colours equal to thofe produced by the common pro-
ceffes.
327. The principal fubflances which are employed
to give a black colour are gall nuts which contain
the allringent principle, or tan, and the red oxide of
iron (r). For a particular account of the nature and
properties of tan, fee Chemistry Index. The black
colour is produced by the combination of the aflringent
principle with the oxide of iron, held in folution by an
acid, and fixed on the fluff. When the particles are
precipitated from the mixture of tan and a folution of
iron, they have only a blue colour 5 but after they are
expofed for fome time to the air, and moiilened with
water, the colour becomes deeper, although the blue
fnade is Hill perceptible. After the particles are fixed
on the fluff, the fhade becomes much deeper.
328. Logwood is not to be confidered as affording a
black dye, but is much employed to give a lullre to
black colours. We have (180.) already deferibed its
nature and properties, among the fabftances from which
red colouring matters are obtained.
329. Black colours are rarely produced by a fimple
combination between the colouring matter and the
fl uff; but are ufually fixed by means of mordants, as in
the cafe of the black particles which are the refult of
a combination of the aflringent principle and the oxide of
iron, held in folution by an acid. But when the par¬
ticles are precipitated from the mixture of an aflrin¬
gent and a folution of iron, they have only a blue co¬
lour. By being expofed to the air, and moiflened with
water, the colour becomes deeper, although the blue
fhade is flill perceptible. No fine black colour is ever
obtained, unlefs the fluffs are freely expofed to the air.
In dyeing black, therefore, the operations muff be con-
dutled at different intervals. Berthollet has obferved
that black fluffs, when brought in contact with oxy-
1 N G. Part II.
gen gas, diminifh its volume, fo that feme portion of it Of Simple
is abiorbed. Co!ours.
II. Of the Proceffcs for Dyeing Woollen Black,
330. In dyeing woollen fluffs black, if a full and fine Muftbefirfl
deep colour is w’anted, it is neceffary that they are pre-Qyed blue,
vioully dyed of a deep blue colour. To remove all the
particles of colouring matter which happen to be loofe-
ly attached to the fluff, it fhould be wralhed in a river
as foon as it is taken out of the vat, and afterwards
cleanfed at the fulling mill. After thefe preliminary
proceffes, the Huffs are ready to receive the black
colouring matter. The procefs of Hellot is the foilow-
ing.
For every hundred pounds of fluff, ten pounds of log- Hellot’j
wmod, and ten pounds of galls reduced to powder, are procefe.
put into a bag and boiled in a middle-iized copper,
with a fufficient quantity of wTater, for 1 2 hours. A
third of this bath is put into another copper, along with
two pounds of verdigrife. The Huff is immerfed in this
bath, and continually Hirred for 2 hours. The bath
fhould be kept hot, but it ought not to boil. At the
end of two hours the Huff is taken out, and a fimilar
portion of the bath is put into the copper, with eight
pounds of copperas (fulphate of iron). During the folu¬
tion of the copperas, the fire is diminifhed, and the bath
is allowed to cool for half an hour, Hirring it well the
whole time. The remainder of the bath is then to be
added, and after making this addition, the bag contain¬
ing the affringent matters fhould be Hrongly preffed, to
feparate the whole. A quantity of fumach from 15 to
20 pounds, is now to be added, and the bath is jufl
raifed to the boiling temperature 5 and when it has gb
ven one boil, it is to be immediately flopped with a lit¬
tle cold wTater. A ffefh' quantity of fulphate of iron,
to the amount of twm pounds, is then added, and the
fluff is kept in it for another hour, after which it is
taken out, wafhed and aired $ it is again put into the
copper, and conftantly ftirred for an hour. It is then
carried to the river, well wafhed, and fulled. To foften
the black colour, and make it more firm, another bath
is prepared with weld. This is made to boil for a mo¬
ment, and when it has cooled, the fluff is paffed through
it. By this procefs, which is indeed fomewhat com¬
plicated, a beautiful black colour is produced.
331. But the proceffes ufually followed for dyeing Common
black, are more fimple. Cloth which has been pre- Procefs’
vioufly dyed blue, is merely boiled in a vat of galls for
two hours. It is then kept two hours, but without
boiling, in the bath of logwood and fulphate of iron,
and afterwards wafhed and fulled. According to Hel-
lot’s procefs, a bath is to be prepared of a pound and a
half of yellow wTood, five pounds of logwood, and ten
pounds of fumach, which is the proportion of the in¬
gredients
(r) Oak bark has been recommended as a fubftitute for gall-nuts in dyeing black, and particularly in dyeing
hats ; and it is faid that the colour thus obtained is fuller, more beautiful and durable, while the operation is ea-
fier and lefs liable to accident. It was firft propofed in the year 1782 by Stephanopoli, a Corfican, and a furgeon
* Phil. in the French army. The examination of the procefs was referred by the French government to Macquer,
Mag. vi. who gave a favourable report of it; and afterwards to Berthollet, who gave a different opinion. The pro-
‘76, cefs has fince been examined, and promifes to be more economical and advantageous, efpecially for dyeing
hats *,
Chap. I. D Y Ti
Of Simple gredients for every r ^ yards of deep brae cloth ; and
Colours tjie ci01 having boiled in this bath for three hours, ten
~ v pounds of fulphate o' iron are added j the cloth ii al¬
lowed to remain for two hours longer, when it is taken
out to be aired, after which it is again returned to the
bath for an hour, and then walhed and lulled.
A cheaper 33?. When lluifs are to be dyed at a lels expence,
procefs. inftead of the blue ground, a brown or root-coloured
ground may be fubitkuted. This brown or fawn colour
is communicated by means of the root of the walnut
tree, or green walnut peels. The fluffs are then to be
dyed black, according to fome of the proceffes already
deferibed.
procefs of ^ 33. The proportions of the ingredients employed by
lifh dyers. t^le Englilh dyers are, for every hundred pounds of cloth
previouliy dyed a deep blue, about five pounds ox lul-
phate of iron, five pounds of galls, and 30 0; logwood.
The firft ftep in the procefs is to gall the cloth, after
which it is paffed through the decoction of logwood,
to which the fulphate of iron has been added.
Arbutus 334- leaves of the arbutus uva urji have been
ufed for recommended, and employed as a iubftitute for galls,
galls. The leaves muff be carefully dried, fo that the green
colour may be preferved. A hundred pounds of wool
are boiled with 16 pounds of iulphate ol iron, and eight
of tartar, for two hours. The day following the cloth
is to be rinfed as after aluming. A hundred and fifty
pounds of the leaves of uva urji are then to be boiled
for two hours in water, and after being taken out, a
fmall quantity of madder is to be added to the liquor,
putting in the cloth at the fame time, which is to re¬
main about an hour and a half. It is then taken out
f Stockholm and rinfed in water, f. By this procefs, it is laid, blue
’Tranf. cloth receives a pretty good black, but white cloth be-
17J3- comes only of a deep brown. It is faid, too, that the
madder and tartar are ufelels ingredients.
Laft ope- 335. After the different operations for dyeing the
ration. cloth have been finilhed, it is walhed in a river, and
fulled, till the water comes off clear and colourlefs.
Soap luds are recommended by fome in fulling fine
cloths, but it is found difficult to free the cloth entirely
from the foap. After the cloth has come from the ful¬
ling mill, fome propofe to give it a dip in a bath of
weld, by which it is faid to be foftened, and the colour
better fixed $ but according to Lewis, this operation,
which in. other cafes is of fome advantage, is ufe-
lefs after the cloth has been treated with the foap
fuds.
III. Of the Procefet for Dyeing Silk Black.
336. In communicating a black colour to filk, dif¬
ferent operations are neceifary, fucb as boiling, galling,
repairing the bath, dyeing, and foftenmg.
337. To give a deeper lhade to filk, it is neceffary
to deprive it of the gummy lubffance to which its itiil-
nefs and elafticity are owing. This is done by boiling
the filk four or five hours with one fifth its weight of
white foap, and afterwards beetling and carefully waffl¬
ing it.
Galling. 338. In conducing the procefs of galling filk, three
fourths of its weight of galls are to be boiled for three or
four hours, but the proportion of galls muff depend on
their quality. After the boiling, the liquor is allowed
to remain at reft for two hours; the filk is then put into
the bath, and left there from 12 to 36 hours, when it
1 N G.
445
is to be taken out, and wafhed in the liver. But a*, uxk
is capable of combining with a great proportion of toe    '_j
aftringent principle, or tan, from which it receives^a
confiderable increafe of weight, it is allowed to remain
for a longer or fhorter time, as the lilk is required to
have more or lefs additional weight, d o communicate,
therefore, to ftlk, what is called a heavy black, it is al¬
lowed to remain longer in the gall liquor ^ the procefs
is repeated oftener, and the lilk is alfo dipped in the uye
a greater number of times.
339. While filk is preparing for the procefs of dye-Dyeing,
ing, the bath is to be heated, and fhould be occafional-
ly ftirred, that the grounds which fall to the bottom
may not acquire too much heat. It ffiould always be kept
under the boiling temperature. Gum and folution of
iron are added in different proportions, according to
the different proceffes. When the gum is diflolved, and
the bath near the boiling temperature, it is left to fettle
for about an hour. The filk, which in general is pre-
viouffy divided into three parts, that each may be luc-
ceilively put into the bath, is immerfed in it. Each
part is then to be three times wrung, and after each
wringing hung up to air. "I he filk being thus expofed
to the action of the air, acquires a deeper fliade. i his
operation being finifhed, the bath is again heated, vvith
the addition of gum and fulphate of iron, and this is re¬
peated two or three times, according as the black re¬
quired is light or heavy. When the procefs of eye¬
ing is finifhed, the filk is rinfed in a veffel with fome
cold water, by turning or fliaking it over.
340. Silk, after it has been taken out of the dye, is Softening,
extremely harflr, to remove which it is fubje&ed to the
operation of foftening. A folution or four or five
pounds of foap for every hundred pounds of filk, is
poured through a cloth into a veffel of water. T. he fo¬
lution being completed, the filk isimmerfed, and allow-
ed to remain in it for about 15 minutes y it is then to be
wrung out and dried.
341. When raw filk is to be dyed, that which has a Dyeing raw
natural yellow colour is preferred. The galling opera-fic¬
tion muft be performed in the cold, if it be propoied
to preferve the whole of the gum, and the elafticity
which it gives to the filk y but if part only of the gum
is wifhed to be preferved, the galling is to be performed
in the warm bath.
34-2. The dyeing operation is alfo performed in the
cold. All that is neceffary is to add the fulphate of
iron to the water in which the fluff is rinfed. By this
fimple procefs the black dye is communicated. It is
then wafhed, once or twice beetled, and dried without
wringing, that its elafticity may not be deftroyed. Raw
filk may be dyed by a more fpeedy procefs. After A fpeedler
galling, it may be turned or fhaken over in the cold P10cefs’
bath 5 and thus by alternately dipping and airing the
fluff, the operation may be completed. It is then to
be wafhed and dried as in the former proceffes.
343. The method of dyeing velvet at Genoa, which Improved
has been limplihed and improved in France* is thus t01
deferibed by Macquer. For every 100 pounds of filk,
20 pounds of Aleppo galls, reduced to powder, are
boiled in a fufficient quantity of wrater for an hour.
The bath is allowed to fettle till the galls have fallen
to the bottom y they are then taken out, and two
pounds and a half of fulphuric acid, twelve pounds of
iron filings, and 20 pounds of gum, are put into a cop¬
per
446
DYE
Subftitute
for galls.
Of Simple per veffel, or cullender, fumiflied with two handles.
Colours, ^ xhis veffel is immerfed in the bath, and fupported
v '' that it may not touch the bottom. The gum, which
is allowed to diffolve for an hour, is to- be occahonally
llirred j and if it appear that the whole of the gum is
diffolved, three or four pounds more are to be added.
Excepting during the operation of dyeing, the cullend¬
er is to remain in the copper, which muff be kept hot
the whole time, but at a temperature below the boiling
point. In galling the filk, one-third of Aleppo galls
is employed, and the fluff fhonld remain fix hours in
the liquor the firfl time, and twelve hours the fecond.
By frequent additions of fulphate of iron, and repeated
immerfions of the fluff', a fine black, according to
Lewis, has been obtained. In the above procefs, the
proportion of fulphate of iron is too fmall, and the
gum, according to fome, being carried off in the walk¬
ing, may be confidered as uielefs. Berthollet thinks
that, although the quantity be excefftve, it has fome
effeft in keeping up the bath, and he adds, if it is to
be diminifhed, it would be ufeful to add the fulphate
of iron in feparate portions during each interval.
344. To diminilh the quantity of galls, which are
an expenfive ingredient in dyeing filk black, other fub-
flances have been propofed as fubflitutes. With this
view the following procefs is recommended.
The filk being boiled and wafhed, is immerfed in a
iftrong decoclion of green walnut peels, and allowed to
remain till the colouring matter of both is exhaufled.
It is then to be flightly wrung out, dried and wafh¬
ed (m). To give the filk a blue ground, logwood and
verdigrife are employed, in the proportion of one ounce
of the latter for every pound of filk. The verdigrife
is diffolved in cold water, and the filk is allowed to re¬
main two hours in this folution. It is then immerfed
in a flrong decodlion of logwood, flightly wrung out,
dried, and afterwards wafhed at the river. The bath
is prepared by macerating two pounds of galls and
three of fumach in 25 gallons of water, over a flow fire,
for twelve hours. The liquid being flrained, three
pounds of fulphate of iron, and the fame quantity of
gum arabic, are to be diffolved in it. The filk is
dipped in this folution at two different times j it is to
remain in the bath two hours each time, and it muff be
aired and dried between each dip. After being twice
beetled at the river, it is dipped a third time, and left
in the bath four or five hours, after which it is to be
dried, wafhed and beetled as before. The temperature
of the bath fhould not exceed 120°. After the firft
dipping, it may be neceffary to add half a pound of
fulphate of iron, and an equal quantity of gum arabic.
345. Silk which has been previoully dyed blue with
indigo, it is faid, takes only a mealy black •, but when
it has been prepared with logwood and verdigrife, it
acquires a velvety lull re. A fine black may be obtain¬
ed from green walnut peel j but the addition of log¬
wood and verdigrife renders a fmaller quantity of ful¬
phate of iron neceffary, and this is of importance, be-
caufe it is apt to weaken the filk. The only ufe of
galls, according to fome, is to increafe the weight of
I N G. Part II.
the filk i for the purpofes of dyeing, fumach is confider- Of Simple
ed fufficient *.
IV. Of the ProceJJes for Dyeing Cotton and Linen * tierthollct,
Black.
246. It is more difficult to communicate a fine black Muft be
to linen or cotton than to filk or woollen fluffs. ToP^A^ty
fucceed in producing a black colour of that degree of y u ’
intenfity which will refill foap, it is neceffary to adopt
particu!ar proceffes. In dyeing animal matters black,
as filk, and wool, the bell colours are obtained on thofe
which have been previoufly dyed blue. This alfo is
an effential preliminary procefs in dyeing linen and
cotton black $ for it is found that the procefs which
fucceeds bell, is firll to give a deep blue grain to the
cotton or linen.
347. The firll part of the procefs is the operation of Galling,
galling. The Huffs which have been previoufly dyed
blue, wrung out and dried, are kept 24 hours in the
gall-liquor, compofed of four ounces of galls to every
pound of thread. A bath is then prepared of a folu¬
tion of iron in acetic acid. This folution is obtained
by faturating the acid with oxide of iron. In France,
vinegar, fmall beer, or fmall wine, is employed for this
purpofe. To promote the acid fermentation, rye meal,
or fome other fubftance, is added, and pieces of old
iron are throwm into the liquid, which are allowed to
remain for fix weeks or twro months, that the acid may
be faturated with the iron. This folution, called iron
liquor in this country, is prepared from fermented
worts, to which old iron is added, as is defcribed above.
Five quarts of the iron-liquor for every pound of Huffs,
are put into a veffel. In this the Huffs are wrought
with the hand, pound by pound, for 15 minutes : they
are then wrung out and aired. This operation is to be
again repeated, taking care to add a frelh quantity of
the iron-liquor, which fliould be carefully fcummed,
after which the Huffs are to be wrung out, aired, and
waffled at the river. In the next operation, a pound
of alder bark for every pound of Huff is boiled in a
fufficient quantity of w ater for an hour. One half of
the bath which was employed in the galling, and about
one half the quantity of fumach as of alder bark, are
then added. The whole is boiled together for two
hours, and Hrained through a fieve. 'When this liquid
is cold, the Huffs are immerfed, wnought pound by
pound, and occafionally aired. They are afterwards
put into the bath, and after remaining for 24 hours,
are wrung out and dried. The above is the procefs
which, according to D’Apligny, is followed at Rouen,
for dyeing cotton and linen.
348. The procefs followed at Manchefter, which is Another
defcribed by Mr Wilfon, is the following. For the procefs.
operation of galling, galls or fumach are employed.
The Huff is afterwards dyed in a bath confiffing of a
folution of iron in acetic acid. This bath is alfo fre¬
quently compofed of alder bark and iron. After hav¬
ing paffed through this bath, the Huff is dipped in a
decoAion of logwood, to which a fmall quantity of
verdigrife has been added. This procefs is to be re¬
peated
(m) The deco&ion of walnut peels is prepared by boiling for 15 minutes, after which it is taken from the
ftre. After it has fubfided, the filk, which has been previouily immerfed in warm water, is dipped in it.
Chap. I. ID Y E
Of Simple peated till a black of fiifficient intenlity is obtained, ob-
Colours. ferving to wafh and dry after each operation.
' ^ 240’. According to Guhliche, a folution of iron may
r/foSn" be prepared by the following procefs. A pound of
of iron. rice is to be boiled in I 2 or 15 quarts of water, till
the whole is diffolved. A fufficient quantity of old
iron made red hot, to reach half way to the fur face of
the liquor, is thrown into the folution. The veflel in
which the folution is kept muft be under cover, but ex- _
pofed to the air and light at lead for a week. In ano¬
ther veffel, containing a quantity of warm vinegar
equal to the folution of rice, an equal quantity of red-
hot iron is to be put. This veffel muft alfo be expofed
in the fame wray to the air and light. After feveral
days, the contents of both veffels are mixed together,
and the mixture is to be expofed for a week to the
open air, after which it is to be decanted and kept for
ufe in a clofe veffel. To give a fufficient black to
linen and cotton, it is only neceffary, it is faid, to fteep
them 24 hours in this folution 5 and if it fhould appear
that the liquor is exhaufted of colouring matter, a fredi
Its applica-portion is to be employed. In this w’ay a fine perma-
tion. nent black is obtained. According to the fame author,
this folution may be advantageoufly employed as a fubfti-
tute for fulphate of iron, in dyeing filk and wooL But
to give them a fine black, filk and woollen ftufts muft
be dipped in a decoiftion of logwood alter they aie
taken from the bath.
Sect. V. Of Brown.
g^O. The laft of the fimple colours is brown. This
is alfo known under the name of fawn colour, (fauve,
Fr.) It is that brown colour wffiich has a (hade of
yellowq and might perhaps be confidered as a com¬
pound colour, although it is communicated to fluffs by
one procefs.
I. Of the Sulfances employed in Dyeing Brown.
3 if i. The vegetable fubftances which are capable of
inducing a fawn or browm colour on diiierent fluffs, are
very numerous, but thofe chiefly employed for this
purpofe are walnut peels and fumach. The peels con-
Walnut ftitute the green covering of the nut } they are inter-
peels. nally of a white colour, which is converted into brown
or black by expofure to the air. I he Ikin when im¬
pregnated with the juice of walnut peels, becomes of a
brown or almoft black colour. When the inner part
of the peel, taken frefh, is put into weak oxymuriatic
acid, it afiumes a brown colour. If the decocftion of
walnut peels be filtered and expofed to the air, its co¬
lour becomes of a deep brown ^ the pellicles on evapo¬
ration are almoft black j the liquor detached from
thefe yields a brown extract completely foluble in wa¬
ter. The colouring particles are precipitated from a
deco&ion of walnut peels, by means of alcohol,. and
they are foluble in water. No apparent change is at
firft produced by a folution of potalh } but it gradually
becomes turbid, and the colour is deepened. A copi¬
ous precipitate of a fawn colour, approaching to an afh
colour, is produced in a decoftion of w’alnut peels by
means of a folution of tin, and the remaining liquor has
a flightly yellow tinge.
Properties. 352* A decoction of walnut peels yields a fmall
quantity of fawn-coloured precipitate by means of a
i n a • 447
folution of alum, and the liquor remains of the fame OfSimple
colour. Sulphate of copper renders it Howdy turbid, and , 0 ^U1 “ .
throws down a fmall quantity of precipitate of a brown-
ifh green colour, leaving the fupernatant liquor of the
fame colour. Sulphate of iron deepens the colour ;
when diluted, the colour becomes brownifli green, with¬
out the depofition of any fediment. Sulphate of zinc
alfo deepens the colour, and produces no precipitate.^
The fame properties are exhibited by a decodion of
the walnut-tree wmod, but the colouring matter is not
obtained from it in Inch abundance as from the peels;
and the bark may alfo be ufed with advantage in dye-
ing.
353. The affinity of the colouring matter of wal-* Advantages
nut peels for wool is very ftrong; and it readily im¬
parts to it a durable colour, which even mordants do
not feem capable of increafing, but they are generally
underftood to give it additional brightnefs. A lively
and very rich colour is obtained with the afiiftance of
alum. Walnut peels afford a great variety of pleafing
{hades, and as they require not the intervention of
mordants, the foftnefs of the wool is preferved, and
the procefs of dyeing becomes both cheap and Ample.
354. Walnut peels are not gathered till the nuts are preparation
completely ripe, when they are put into large calks,
along with as much water as is fufficient to cover them.
When ufed in dyeing at the Gobelins in Paris, Bcr-
thollet informs us, they are kept for upwards of a year,
and very extenfively ufed ; but if not made ufe of till
the end of two years, they yield a greater quantity of
colouring matter, at which time their odour has be¬
come peculiarly difagreeable and fetid. I he peels fe-
parated from the nuts before they arrive at maturity,
may likewdfe be ufed in dyeing, but in this ftate they
do not keep fo long.
355. Sumach {rhus coriaria, Linn.) is a ftirub pro-Sumach,
duced naturally in Paleftine, Syria, Portugal, and Spain,
being carefully cultivated in the twm laft of thefe coun¬
tries. Its ihoots are annually cut down, dried, and re¬
duced to powder in a mill, by which procefs they are
prepared for the purpofes of dyeing.
356. The infufion of fumach, which is of a fawn co-pr0pertie?i:
lour with a greeniih tinge, is changed into a brown by
expofure to the air. A folution of potafti has little ac¬
tion on the recent infufion of fumach ; its colour is
changed to yellow by the adflion of acids ; the liquor
becomes turbid by means of alum, a fmall quantity of
precipitate being at the fame time formed, and the fu¬
pernatant liquor remaining yellow. A copious preci¬
pitate of a yellowifti green colour is thrown down by
fulphate of copper, and the liquor remains clear. No
change is fpeedily produced by muriate of loda (com¬
mon fait), but it becomes rather turbid at the end of
fome hours, and its colour is rather clearer. Sulphate
of copper produces a copious precipitate of a yellowifti
green, which after Handing fome hours, changes to a
brownifh green ; the fupernatant liquor, which is flight¬
ly yellowq remains clear. Sulphate of zinc renders the
liquor turbid, darkens its colour, and produces a deep
blue precipitate ; iW when the fulphate of zinc is pure,
the precipitate, which is of a brownifli fawn colour, is
in very fmall quantity. Acetate of lead gives a copi¬
ous precipitate, of a yellowifh colour ; the fupernatant
liquor is of a clear yellowr colour. No aftringent has
id ftrong a refemblance to galls as fumach ; but the
precipitafrr
Of Simple
Colours.
Bark of
birA.
Sandal
wood.
448 DYE
precipitate thrown down from an infufion of it by a fo-
lution of iron, is not fo copious as that which is yield¬
ed by an equal quantity of galls, on which account fu-
mach may be generally employed as a fubftitute for
galls, only its quantity will require to be increafed.
357. The bark of the birch^ree {betula alba, Lin.)
yields a deco£lion of a clear fawn colour, but it foon
becomes turbid and brown. The addition of a folu*
tion of alum in the open air, produces a copious yel¬
low precipitate *, a folution of tin gives alfo a copious
precipitate of a clear yellow colour. With folutions of
iron the decoction of the birch-tree ftrikes a black co¬
lour, and it diffolves in conliderabie quantity the oxide
of iron, but in fmaller proportion than the decoction of
walnut peels. On account of this property it is em¬
ployed in the preparation of black vats for dyeing
thread.
3^8. Saunders, or fandal wood, is alfo employed
for the purpcfe of giving a fawn colour. There are
three kinds of fandal wood, the white, the yellow, and
the red. The laft only, which is a compact heavy
wood, brought from the Coromandel c._ aft, is ufed in
dyeing. By expofure to the air it becctnes of a brown
colour *, when employed in dyeing, it is reduced to fine
powder, and it yields a fawn colour with a browniih
ihade, inclining to red. But the colouring matter
which it yields of itfelf is in fmall quantity, ai d it is
faid that it gives harfhnefs to woollen fluffs. When it
is mixed with other fubftances, as fumach, walnut peels,
or galls, the quantity of colouring matter is increafed j
it gives a more durable colour, and produces con::der-
able modifications in the colouring matter with which
it is mixed. Sandal wood yields its colouring matter
•to brandy, or diluted alcohol, more readily than to
water.
Soot. 359. Soot communicates to woollen fluffs a fawn or
brown colour, of a lighter or deeper fhade, in propor¬
tion to the quantity empl yed ; but the colour is fad¬
ing, and its affinity for wool is not great *, and befides
leaving a difagreeable fmell, it renders the fibres harfh.
In fome' manufactories, it is employed for browning
certain colours, and it produces fhades which could not
other wife be eafily obtained.
II. Of the Procejfes for Dyeing IVooUea, &c. a Fawn
or Brown Colour.
With wal¬
nut peels.
Berthollet’s
experi¬
ments.
360. In dyeing with walnut peels, a quantity pro¬
portioned to the quantity of fluff, and the intenlity of
fhade wranted, is boiled for fifteen minutes in a copper.
All that is neceffary in dyeing with this fubftance is,
to moiften the cloth or yarn with warm water, previous
to their immerfion in the copper, in which they are to
be carefully ftirred till they have acquired the proper
fhade. This is the procefs, if the aluminous mordant
is not employed. In dyeing cloth, it is ufual to give
the deepeft fhades firft, and the lighter ones afterwards;
but in dyeing woollen yarn, the light fhades are given
firft, and the deeper ones afterwards. An additional
quantity of peels is joined to each parcel.
361. Berthollet made a number of experiments to
afeertain the difference of colour obtained from the
fimple decodlion of walnut peels, and the addition of
metallic oxides as mordants. The oxide of tin, he
found, yielded a clearer and brighter fawn colour than
that of the fimple decodlion. The oxide of zinc pro-
1
I N G. Part II.
duced a ftill clearer colour, inclining to afti or gray. Compound
The colour from oxide of lead had an orange caft, Lolouis.
while that from oxide of iron was of a greenifh ~v''_
brown *•
362. A fawn colour, which has a fhade of green, ^
is obtained from fumach alone ; but to cotton fluffs Dyeing
which have been impregnated with printers mordant, with fu-
or acetate of alumina, fumach communicates a good ,nach*
and durable yelknv. Here, however, forfte precaution
is neceffary in the ufe of this fubftance for this purpofe j
for as the colouring matter is of fo fixed a nature, the
ground of the ftuii cannot be bleached by expofure on
the grafs* This inconvenience is avoided by impreg¬
nating the whole of the ftuff with different mordants,
producing in this wray a variety of colours, and leaving
no part white.
363. Vogler employed the tincture of faunders wood With fandal
for dyeing patterns of wool, filk, cotton, and linen, W00(l-
having previouily impregnated them with a folution of
tin, and afterwards wafhing and drying them. Some¬
times he ufed the folution unmixed, and at other times
added fix or ten parts of water, and in whatever way
he employed it, he obtained a poppy colour. When
the mordant employed was folution of alum, the colour
was a rich fcarlet •, with fulphate of copper it was a
clear crimfon, and with iulphate of iron a beautiful
deep violet f. f CrdlAnn.
1790.
Chap. II. Of Compound Colours.
364. A MIXTURE of two colouring fubftances, it is Nature of
well known, produces a very different ftiade from that compound
of either of the uncombined colouring matters } hence co*ours*
compound colours are obtained, which are merely mix¬
tures of fimple colours. It would undoubtedly be a
delirable thing to afeertain with accuracy the peculiar
fliade produced by the combination of two colouring
matters 5 but thefe refults can only be certainly known
by experiment, becaufe by the aftion of different fub¬
ftances in the baths, they are fubjedl to great variations
in their effefts, according to the affinities which are
brought into action, and the new combinations which
are formed. What is natural to colouring particles is
not to be confidered as a conftituent part of compound
colours, but only the difference of ffiade which they
ought to affume, with a particular mordant, or in a
particular bath. The effedls, therefore, of the chemi¬
cal agents employed in thefe proceffes, and the refult
of different combinations, ought to be particularly at¬
tended to. It is in dyeing compound colours that {kill
and ingenuity are moil confpicuous, and their applica¬
tion of greateft utility, to enable the dyer to vary his
proceffes, according to the Ihade defired, and at the
fame time to accompliffi his operations by the ffiorteft
and cheapeft means. ,
365. As compound colours are obtained by the mix-Great va-
ture of fimple colours, very different fhades will be ob-r ety
tained from different proportions of the fimple colours 5 flia<*e*
hence compound colours exhibit an indefinite variety
of fhade, and the procefles by which they are produced
are very numerous. It would extend this treatife to an
unufual length, were we to attempt to deferibe every
variety of fliade which is obtained from the mixture of
fimple colours. We fliall therefore limit our obferva-
tions to fome of the principal compound colours, and
an
»
Chap. II. D Y E
Compound an account of tlie procefles by which they are obtained,
Colours. ]eaving it to our readers, who have made themfelves
v-"”"' familiar with the principles already detailed, to vary
thefe colours, by employing different proportions and
difterent combinations of fimple colouring matters.
366. Compound colours have been ufually divided
into four dalles, namely, green, purple, orange, and
gray or drab colour. Thefe are obtained from mix¬
tures of the following fimple colours.
r. Blue and yellow produce a green.
2. Red and blue, a purple, &c.
3. Red and yellow, orange.
4. Black and other colours, gray, &c.
The following feftions will be occupied in a Ihort de¬
tail of the methods wThich are ufually employed in pro¬
ducing thefe different compound colours.
Sect. I. Of the Mixture of Blue and Yellow, or Green.
Various 367. Green colours, from the great variety of fhades
fliades of which they exhibit, have been long known by differ-
£lLea‘ ent names, by which the intenfity of fhade is chara&e-
rifed, fuch as fea-green, apple-green, meadow or grafs
green, pea-green, parrot-green, &c. Many plants afford
a green colour, fuch as brome grafs (bromus fecalinus,
Lin.), green berries of rhnmnus frangula, wild chervil
(cheerophyllum fylvefre^ Lin.), purple clover {trifolium
pratenfe), common reed {arundophragmites'). Thefe co¬
lours, howrever, do not poffefs fufhcient permanency.
According to D’Ambourney, indeed, a permanent
green may be obtained from the fermented juice of the
berries of the berry-bearing alder {rhamnux frangula}.
Having previoufly prepared the cloth with tartar, folu-
tion of nitrate of bifinuth and common fait, he added
to the fermented juice of the berries, after it was warm¬
ed, a fmall proportion of acetate of lead *, and in this
bath he communicated to the cloth an intermediate
fhade between parrot and grafs green. But it is ufual¬
ly from the mixture of blue and yellow that green is ob¬
tained j and it may be obferved, that it requires much
(kill and experience, efpecially in giving light fhades,
to produce a colour wdfich is uniform, and entirely
without fpots.
I. Of the Procejfes for Dyeing Woollen Stuff's Green.
Common 3^8. To dye woollen green, either the yellow or
procels. tjle yue jyg may gjven to gut wjlen
fluff is firli dyed yellow', and in this flate is introduced
into the blue vat, part of the yellow colouring matter
being dinolved in the vat, communicates to it a green
colour, which renders it unfit for dyeing any other co¬
lour than green. To avoid this inconvenience, there¬
fore, the blue colour is firft given, and afterwards the
yellowr. It would be quite unneceifary to refume the
account of any part of the proceifes for dyeing blue,
which have been already detailed. It is proper, however,
to add, that the intenfity of the blue fhade mult be pro-
' portioned to the green, or to the depth of the green
colour which is wifhed to be' obtained. Thus, for in-
flance, to produce a parrot green, a ground of fky
Llue is given, and for the green like that of a drake’s
neck, a deep blue is required. When the blue dye
has been communicated, the yellow is afterwards given,
according to fome of the precedes which have been al-
Vot. VII. Part II.
I N Q. 449
ready delcribed for dyeing yellow. The proper ground Compound
being communicated to the cloths, they are wafhed in c^our:;' ;
the nailing mill, and boiled as for the common procefs ^
of w’elding 5 but when the fhade is light, the propor¬
tion of falts fhould be lefs. Cloths which are to re¬
ceive light fhades are firfl boiled, and wdien thefe are
taken out, tartar and alum are added in frefh portions,
till the cloths which are intended for the darkeft fhades
are boiled. The procefs of welding is conduced in
the fame way as for dyeing yellow, with this difference,
that a larger proportion of weld is employed, except¬
ing for lighter fhades, when the proportion muft be
fmaller. In dyeing green, it is ufual to have a fuccef-
fion of fhades at the fame time ; the procefs is be¬
gun with the deepeft, and ends with the lightefl. Be¬
tween each dip there fhould be an interval of one-half
or three-quarters of an hour, and at each interval wja-
ter is added to the bath. It is the pradlice of fome
dyers to give each parcel two dips, beginning the firfl
time with the deep fhades, and the fecond with the
lighter ones ; but when this practice is folhnved, the
time of immerfion fhould be fhortened. In dyeing very
light fhades, the bath fhould never be permitted to
reach the boiling temperature. For deep greens, a
browning is given with logwood, and a fmall propor¬
tion of fulphate of iron.
369. For fome kinds of green, fulphate of indigo is Saxon
employed ; and in this cafe either the blue and yellow green,
are dyed feparately, or the whole of the ingredients are
mixed together in the bath, and the whole procefs is fi-
niflied at a fingle operation. The colour thus obtained
has been diilinguifhed by the name of Saxon preen.
The following is the procefs recommended by Dr Ban¬
croft.
370. “ The moll beautiful Saxon greens (fays he)
may be produced very cheaply and expeditioufly, by
combining the lively yellow which refults from querci¬
tron bark, murio-fulphate of tin, and alum, with the
blue afforded by indigo when diffolved in fulphuric acid,
as for dyeing the Saxon blue.
“ To produce this combination mofl advantageoufly,
the dyer, for a full-bodied green, fhould put into the
dyeing veffel after the rate of fix or eight pounds of
powdered bark, in a bag, for every 100 lb. weight of
cloth, with only a fmall proportion of water as foon as
it begins to grow warm ; and w'hen it begins to boil,
he fhould add about fix pounds of murio-fulphate of
tin (with the ufual precautions), and a few minutes af¬
ter, about four pounds of alum ; thefe having boiled
together five or fix minutes, cold w'ater fhould be add¬
ed, and the fii'e diminifhed fo as to bring the heat of
the liquor nearly down to what the hand is able to
bear ; and immediately after this, as much fulphate of
indigo is to be added as will fuffice to produce the
fhade of green intended to be dyed, taking care to mix
it thoroughly with the firfl folution by flirring, &c. ;
and this being done, the cloth previoufiy fcoured and
moiliened, fhould be expeditioufly put into the liquor,
and turned very brifkly through it for a quarter of an
hour, in order that the colour may apply itfelf equally
to every part, which it will certainly do in this way
with proper care. By thefe means, very full, eiven, and
beautiful greens may generally be dyed in half an
hour j and during this fpace, it is bell to keep the li¬
quor .at rather lefs than a boiling heat. Murio-fulphate
3 L of
45^
Compound
Colours.
DYEING.
Part II.
* Phil, of
Ptrm. Col.
336-
Prepara¬
tion.
Saxon
green.
of tiu is infinitely preferable, for this ufe, to the dyer’s
fpirit j becaufe the latter confifts chiefly of nitric acid,
which by its highly injurious action upon indigo, would
render that part of the green colour very fugitive, as I
have found by repeated trials. But no fuch efleet can
refult from the murio-fulphate of tin, lince the muriatic
acid has no action upon indigo *, and the fulphuric is
that very acid which alone is proper to dilfolve it for
this ufe.
“ Refpefting the beauty of the colour thus produced,
thofe who are acquainted with the unequalled luftre and
brightnefs of the quercitron yellows, dyed with the tin
bafis, mult neCcffarily conclude, that the greens com-
pofed therewith will prove infinitely fuperior to any
which can refult from the dull muddy yellow of old fu-
ftic j and in point of expence, it is certain that the
bark, murio-fulphate of tin, and alum, neceflary to dye
a given quantity of cloth in this way, will coll lefs than
the much greater quantity (fix or eight times more) of
fuftic, with the alum neceffary for dyeing it in the com¬
mon way, the fulphate of indigo being the fame in
both cafes. But in dyeing with the bark, the veflel is
only to be filled and heated once j and the cloth, with¬
out any previous preparation, may be completely dyed
in half an hour ; whilft in the common way of produ¬
cing Saxon greens, the copper is to be twice filled ;
and to this mufi be joined the fuel and labour of an
hour and a half’s boiling and turning the cloth,, in the
courfe of preparation, befides nearly as much boiling in
another velfel to extraft the colour of the fuftic j and
after all the dyeing procefs remains to performed,
which will be equal in time and trouble to the whole
of the procefs for producing a Saxon green with the
bark j fo that this colour obtained from bark will not
only prove fuperior in beauty, but in cheapnefs, to that
dyed as ufual with old fuftic
II. Of the FroceJJes for Dyeing Silk Green.
371. In giving filk a green colour, greater precau¬
tion is neceffary, to preferve uniformity of colour, and
to prevent fpots and ftripes. Silk which is intended to
receive a green colour, is fcoured in the fame way as
for other colours > but for light (hades, the fcouring
muft be as complete as for blue. Silk which is to be
dyed green, is firft dyed yellow, and being well alu-
med, it is {lightly walked at the river, and divided into
fmall parcels, that it may receive the colouring matter
uniformly, and then carefully turned in the weld bath.
When the ground is fuppofed to have acquired a fufti-
cient degree of intenfity, a pattern is put into the blue
vat, to afeertain the proper (hade. When this is the
cafe, the filk is taken out of the bath, walked, and im-
merfed in the blue vat. To produce a deeper colour,
and at the fame time to give variety of lhade, a decoc¬
tion of logwood, fuftic, or anotta, is added to the yel¬
low bath, after the weld has been taken out. For very
light lhades, fuch as apple and fea green? it is fcarcely
neceffary to add, that a weaker ground is to be given.
For all light {hades except fea green, the procefs is
found to fucceed better when the yellow is communi¬
cated by baths which have been already ufed 5 but
thefe baths Ihould not contain any logwood or fuftic.
372.. Saxon green is produced by means of fulphate
of indigo. This is a brighter, but lefs durable colour
than the former. This proceis is conducled by boiling
as for welding, after which the cloth is walked. Fu- Compound
flic in chips is enclofed in a bag, put into the fame bath, Colours. .
and boiled for an hour and a half, when it is taken
out, and the bath allowed to cool till the hand can
bear it. A pound and a quarter of fulphate of indigo
for each piece of cloth of eighteen yards, is added.
The cloth is at firft to be turned quickly, and after¬
wards more llowly, and it Ihould be taken out before
the bath boils. Some dyers put in only two-thirds of
the folution at firft } and after two or three turns, take
out the cloth, and add the other one-third. By this
means the colour is more uniform.
373. To produce Saxon green at one operation, the By one ope-
following procefs is recommended by Dr Bancroft. Araft°n-
bath is prepared of four pounds of quercitron bark,
three pounds of alum, and two pounds of murio-ful¬
phate of tin, with a fuflicient quantity of water. The
bath is boiled ten or fifteen minutes, and when the li¬
quor is fo far reduced in temperature as the hand can
bear it, it is fit for dyeing. By adding different pro¬
portions of fulphate of indigo, various and beautiful
{hades of green may be obtained, and the colour thus
produced is both cheap and uniform. Care fliould be
taken to keep the bath conftantly ftirred, to prevent the
colouring matter from fubfiding. Thofe (hades which
are intended to incline molt to the yellow, fhould be
dyed firft ; and by adding fulphate of indigo, the
green, having a {hade of blue, may be ootained. Ibis
procefs, Dr Bancroft obferves, is the moft commodious
and certain for dyeing the moft beautiful Saxon greens
upon filk f. f Phil.
374. To produce Englifh green, which is more Perm. Col,
beautiful than common green, and is faid to be more 346.
durable than the Saxon green, Guhliche gives the fol- *
lowing procefs. He firft dyes the filk of a light-blue
in the cold vat already deferibed (316.), then foaks it
in wTarm water, wafhes it in a ftream, and dips it in a
weak folution of alum. He then prepares a bath of
fulphate of indigo, one ounce of folution of tin, with
the tinfture of French berries made with aceto-citric
acid. The filk is kept in this bath till it has obtained
the defired colour. It is then waflied and dried in a
ftiady place. Lighter lhades may be dyed after¬
wards J. t Berthollet,
ii. 319.
III. Of the Proce/fes for Dyeing Cotton and Linen
Green.
375. Cotton and linen, after being fcoured in the Blue firft
ufual way, are firft dyed blue ; and after being cleanfed, given,
they are dipped in the weld bath, to produce a green
colour. The ftrength of the blue and yellow is pro¬
portioned to the (hade of green which is wanted. But
as it is difficult to give to cotton velvet an uniform co¬
lour in the blue vat, it is firft dyed yellow with turme¬
ric, and the procefs is completed by giving it a green
with fulphate of indigo. The fame refult, however,
will be obtained by commencing the procefs either with
the yellow or the blue. _
376. The procefs which D’Apligny defenbes for procefs for
dyeing cotton velvet, or cotton thread a fea or apple cotton vel-
green in one bath is the following. A quantity of vet.
verdigrife is diffolved in vinegar, and the mixture is
kept excluded from the air in the heat Ox a fto\ e for
fifteen days. A quantity of potaffi equal in weight to
the verdigrife employed is diffolved in water, and four
hours
Chap. II.
DYE
Olive
green
Compound hours before dyeing it is added to the folution of ver-
Colouri. Jlgrife. This mixture is to be kept hot, One ounce
* of alum in five quarts of water for each pound of ftuff
being prepared, the cotton thread or velvet is foaked in
this folution. It is then taken out, and the verdi-
grife mixture being added to the folution ol alum, it is
again introduced to be dyed.
377. The different ihades of olive green, and drake’s
neck green, are given to thread after it has received a
blue ground, by galling it, and dipping it in a weaker
or ftronger bath of iron liquor, then in the weld bath,
to which verdigrife has been added, and afterwards in
the bath with fulphate of copper. I he colour is lallly
to be brightened with foap.
Green from 378. Cotton dyed with Pruflian blue maybe dyed
pruffian green by previoully Illuming while it is ftill wet with
the blue, and then dipping in a weld bath, the ftrength
of which is proportioned to the fhade required. Ihe
colour from weld is more lively than that obtained front
fullic. But fuftic which gives a deeper lhade than
weld, and diminifhes the brightnefs of the blue, is to
be preferred when a green with an olive fhade is want-
blue.
ed- # . .
Central 379* The (hade of green given to any fluff, it is ob-
remarks. vious, mufl vary according to the intenfity of the blue
fhade, the ftrength of the yellow bath, and the nature
of the yellow colouring matter employed. Yellow co¬
lours are rendered more intenfe by means of alkalies,
fulphate of lime and ammoniacal falls ; but become
fainter by means of acids, alum, and folutions of tin.
In dyeing Saxon green the refult will be different ac¬
cording to the procefs which is followed. The effe&s
will be different by adding a yellow to a Saxon blue,
from the procefs in which the fulphate of indigo is mix¬
ed with the yellow ingredients ) becaufe in the latter
cafe the fulphuric acid has a confiderable acfion on the
colouring matter, and thus diminifhes the intenfity of
the yellow. As the particles of indigo have a ftronger
affinity for the ftuff than the yellow colouring matter,
in dyeing a fucceftion of fhades in a bath in wriiich both
are mixed, the bath being firft exhaufted of the indigo,
the laft fhades incline more to the yellow on ac¬
count of the predominance of the yellow colouring
matter.
Sect. II. Of the Mixture of Red and Bluey or
Purple^ &c.
380. By the mixture of red and blue, violet, purple,
dove-colour, lilac, and a great variety of other ihades,
according to the proportions of the fubftances employ¬
ed, or the predominance of the blue or the red, are
produced. In fluffs •which are to be dyed violet, a
deeper blue muft be given, but for purple colours, the
ground requires to be of a lighter blue; but in lilac and
fimilar light colours, it is neceffary that both the blue
. and the red have a light lhade.
I. Of Dyeing Wool Violet, Purple, &c»
Blue firft 381. In the attempts which have been made to com-
,given. municate a violet or purple colour to a fcarlet ground,
according to the obfervations of Hellot, the colour is
very unequal. It becomes therefore neceflary to give
the blue colour firft j and for violets and purples, the
fhade of blue ought not to be deeper than that of fky
1 N G. 45*
blue. The (luff being dyed blue, is boiled with alum,
and two fifths of tartar, and is afterwards dipped in a ._ ° 1
bath compofed of nearly two thirds the quantity of co¬
chineal required for fcarlet, with the addition of tartar.
The fame procefs, indeed, as for dyeing fcarlet, is fol¬
lowed. It is a common praftice to dye thefe colours
after the reddening for fcarlet, making fuch additions
of cochineal and tartar as the intenfity of the fhade may
require.
382. For lighter fhades, as lilacs, dove-colours, &c. Lilac,
the fluff may be dipped in the bath which has ferved
for violet and purple, and is now fomewhat exhaufted,
taking care to add a quantity of alum and tartar. For
reddiih fhades, fuch as peach blolfom, a fmall propor¬
tion of folution of tin is added. It may be obferved,
in general, that although the proportion of cochineal is
lefs in dyeing lighter fhades, the quantity of tartar mufl
not be diminifhed.
383. To obtain the fame colours, a fhorter and lefs Cheaper
expeniive procefs is recommended by Poerner. In this an(l fl(lorter
procefs he employs fulphate of indigo. He boils the Proce
ftuff in a folution of alum, in the proportion of three
ounces of the latter to one pound of the former, for an
hour and a half, and afterwards allows it to remain in
the liquid for a night after it has cooled. The dyeing
bath is prepared with an ounce and a half of cochineal,
and two ounces of tartar, which are boiled for three
quarters of an hour : two ounces and a half of fulphate
of indigo are then added, the whole is ftirred, and boil¬
ed gently for j 5 minutes. The dyeing operation is con¬
ducted in the ufual way, and a beautiful violet is thus
obtained. To have all the variety of fhades which
are produced by the mixture of red and blue, the pro¬
portion of the fulphate of indigo is increafed or dimi¬
nifhed. It is fometimes increafed to five ounces, and di¬
minifhed to five drachms, for each pound of ftuff. The
quantity of cochineal is alfo varied, but when it is lefs
than an ounce, the colour is dull. Different proportions
of tartar are alfo employed. Fo produce variety of
fhades, the ftuff is alfo prepared with different propor¬
tions of folution of tin.
384. To communicate a purple colour to wool, as Purple from
well as fome other fhades, logwrood, with the addition .ogwooJ.
of galls, has been employed. The ftuff is previoufly
dyed blue, and to give a brown fhade, fulphate of iron
is ufed 5 but the colours thus obtained are not perma¬
nent. By the following procefs, defcribed by Decroi-
zille, a durable dye is produced, by means of this wood.
He difiblved tin in fulphuric acid, to which were added
common fait, red acidulous tartrite of potafli, and
fulphate of copper; or it m?y be more, conveniently
done by making a folution of tin in a mixture of ful¬
phuric acid, common fait, and water, to which are
to be added the tartrite and fulphate in the flate of
powder. Of this mordant not lefs than 1500 quarts
were made in twenty four hours, in a leaden veffel to
which a moderate heat was applied. A very lucrative
trade w7as carried on for three years by Decroizille,
who fold it at the rate of is. 3d. fterling per pound.
385. If wool in the fleece is to be dyed, it will re-Procefs.
quire a third of its weight of this mordant, wdiile a fifth
is a proportion fufficient for fluffs. A bath is prepared
of fuch a degree of temperature as the hand can bear,
with which the mordant is properly mixed, and the
wool or Huff dipped in it and ftirred, the fame degree
3 L 2
45 2
Compounil
Colours.
Different
fhades from
other fub-
ftances.
Nature of
the procefs.
DYE
of temperature being kept up for two hours, and in-
creafed a little towards the end ; after which it is taken
out, aired, and well walked. A frelh bath of pure wa¬
ter is prepared at the fame temperature, to which is ad¬
ded a lufficient quantity of the decoction of logwood j
the duff is then immerfed, ftirred, and the heat in-
creafed to the boiling temperature, which is to be con¬
tinued for 15 minutes, after which the fluff being taken
out, aired, and carefully rinfed, the procefs of dyeing
is completed. If for every three pounds of wool, one
pound of a decoction of logwood has been ufed, and a
proportionate quantity for fluffs which require lefs, a
fme violet colour is produced, to which a fufficient quan¬
tity of brafil-wood imparts the fhade known in France
by the name of prune de Mon fieur.
386. Logwood and bralil, fultic and yellow wood,
are colouring fubflances which may be fixed with ad¬
vantage upon wool by means of this mordant. The
colour communicated by the two 'firfl of thefe is liable
to be changed in the fulling by the aflion of the foap
or urine employed for that purpofe •, but this change,
which is always produced by alkaline fubftances, is re¬
medied by a flightly acid bath a little hot, called
brightening-, for which the fulphuric acid has the pre¬
ference. The colour becomes as deep, and frequently
piuch brighter than before the change. Wools which
have been dyed by means of this mordant, are faid to
admit of being fpun into a finer and more beautiful
thread, than by the ufe of alum. If the ufe of fulphate
of copper is omitted, more beautiful colours are produ¬
ced by fuflic and yellow wood, as well as by weld. An
orange red colour is communicated by madder, but not fo
deep as with a fimilar quantity of alum. When fulphate
o! copper is omitted, the wool is faid to become much
hardier, and the mordant thus prepared yields but in¬
different colours with logwood, and in particular with
braHl-wood. The ufe and carriage of this mordant
are inconvenient, on account of the heavy fediment by
which the veffel is half filled under a corrofive liquor,
capable only of being kept in Hone ware. Thefe in¬
conveniences may be remedied by the omiffion of the
water in the receipt, which leaves only a pafte more
conveniently ufed, and the carriage of it two-fifths
cheaper.
387. The above procefs is thus explained by Ber¬
th ollet. The decompofition of the muriate of ioda is
effected by the adlion of the fulphuric acid, and the
muriatic acid being thus difengaged, diffolves the tin,
part of which is precipitated by means of the tartaric
acid, producing the fediment already mentioned. The
oxide of copper produces the blue with the colouring
particles of the logwood ; the violet is formed by the
oxide of tin with the fame wood, and the red, with
the colouring matter of the braid-wood. The fame
ingenious chemift farther obferves, that as an excefs of
acid is retained in the liquor, it might probably be of
advantage to employ acetate as a lubilitute for fulphate
of copper, in which cafe the aclion of the free acid
would be moderated. He thinks it would Hill be
more advifeable to make ufe of verdigrifej becaufe the
uncombined part of the oxide of copper would, in that
cafe, unite with the excefs of acid, on which account
a fmaller quantity of acid would remain in the liquor 5
und probably the quantity of tartar might be dimirulh-
I N G.
ed, as a fmaller
tated *.
Part II.
quantity of tin would thus be precipi- Compound
Colours.
II. Of Dyeing Silk Violet or Purple. * Bertholkt,
n . . . . ii. 340.
388. Silk is capable of receiving two kinds of vio-Two kinds
let colours, denominated the fine and the falfe, the lat-of violet,
ter of which is produced by means of archil or brafil-
wood. When the fine violet colour is required, the
filk muff firff be paffed through cochineal, and dipped
afterwards in the vat. The preparation and dyeing of
the filk with cochineal are the lame as for crimfon,
with the omiflion of tartar and folution of tin, by means
of which the colour is heightened. The quantity of
cochineal made ufe of is always proportioned to the re¬
quired ftiade, whether it is more or lefs intenfe ; but
the ufual proportion for a fine violet colour is two
ounces of cochineal for each pound of filk. When the
filk is dyed, it is waihed at the river, twice beetled,
dipped in a vat more or lefs ftreng, in proportion to
the depth of the violet (hade, and then waihed and
dried w ith precautions fimilar to thole which all colours
require that are dyed in the vat. If the violet is to
have greater ftrength and beauty, it is ufual to pafs it
through the archil bath, a practice which, though fre¬
quently abufed, is not to be difpenfed with for light
(hades, which would otherwife be too dull.
389. When filk has been dyed with cochineal ac-p je
cording to the above directions, only a very light lhade
is requifite for purple ; the lhades which are deepeft
are dipped in a weak vat, while dipping them in cold
water is fufticient for luch as are lighter, the water
having been incorporated with a linail quantity of the
liquor of the vat, becaufe in the vat itfelf, however
weak it might be, they would acquire too deep a tinge
of blue. In this manner are the light lhades of this
colour, fuch as gilly-flower, peach bloffom, &c. pro¬
duced by diminilhing the quantity of cochineal.
390. There are various ways of imparting to filk pajfe v;0
what are denominated the lalfe violets j but thofe lets,
which are moil frequently ufed, and poffeffed of great-
eff beauty, are prepared with archil, the bath of which
is, in point of ffrength, to be luited to the colour re¬
quired. Having been beetled at the river after fcour-
ing, the filk is turned in the bath on the fkein Hicks 5 and
when the colour is deemed fufficiently deep, a pattern
is tried in the vat, to afeertain whether it takes the vio¬
let colour intended to be produced. If the lhade is
found to have acquired the proper depth, the lilk is
beetled at the river and dipped in the vat, in the lame
way as for the fine violet colours j and lels either of
the blue or of the archil colour is given, according as
it is meant that the red or blue Ihade of the violet co¬
lour Ihould predominate.
391. The procefs recommended by Guhliche for Procefs of
communicating a violet colour to lilk is the following. Ouhliche.
A pound of liik is to be (baked in a bath of two ounces
of alum, and a like, quantity of folution of tin, after hav¬
ing carefully pouied off the fediment formed in the
mixture. The dye-bath is prepared with two ounces of
cochineal reduced to powder with a dram of tartar,
and the remaining part of the bath which has anfwered
the purpofe of a mordant, with the addition of a fuffi¬
cient quantity of water. When (lightly boiled, fuch a
quantity of folution of indigo is added as may communi¬
cate
1
Chap. II. . , 0 Y E
Compound cate to the bath a proper (hade of violet 5 after which
Colours, the filk is immerfed, and boiled till it nas acquired the
v intended {hade. It is then wrung, walhed in a ftream,
and like every other .delicate colour, muil be dried
in the (hade. The light {hades exhauft the bath.. But
it ought to be obferved, that this colour, which is faid
to be a beautiful violet, poffefles but little durability,
• and is apt to ailutne a reddish tinge, owing to th.e co¬
lour of the indigo fading firft.
Another. 392. A violet colour maybe imparted to filks, by
immeriing them in water impregnated with verdigrife,
as a fubftitute for aluming, and next giving them a
bath of logwood, in which they affume a blue colour,
which is converted to a violet, either by the addition
of alum to the bath, or by dipping them in a weaker
or flronger folution of that fubftance, which communi¬
cates a red colour to the particles of logwood. Ihis
violet poffeffes but a fmall degree of beauty, and little
durability. But if alumed filk be immerfed in a bath of
bralil-wood, and next in a bath of archil, arter wafh-
ing it at the river, a colour is obtained poffeffing a
much higher degree of beauty and intenfity. i he
procefs defcribed above (3^5‘)» ^or dyeing wool, fuc-
ceeds equally - well, according to M. Oecroizille, in
communicating to lilk a violet colour.
III. Of Dyeing Cotton and Linen Violet.
Common 393. The mod: ordinary mode by which a violet co-
pruceis. lour is communicated to cotton and linen duds, is firit to
give them a blue ground in the vat, proportioned to
the required (hade, and to dry them. They are after¬
wards galled, in the proportion of three ounces of galls
to a pound of fluff, and being left in this bath for 1 2
cr 1 5 hours, ape wrung out and dried again. They
are next paffed through a decoftion of logwood, aud
when thoroughly foaked and taken out, the bath re¬
ceives an addition of two drams of alum, and one of
diffolved verdigrife for each pound of cotton or thread.
The fkeins are then dipped again on the {kein (licks,
and turned for about ' 5 minutes, when they are taken
out and aired. They are next immerfed in the bath
for ' 5 minutes, taken out and wrung. To complete
the procefs, the vat employed is emptied ft half of the
deco&ion of logwood not formerly made ufe of is now
poured in, with the addition of two drams of alum,
and the thread is again dipped in it till it has acquired
the (hade propofed, which mu ‘ always regulate the
flrength or weaknefs of the decodlion of logwood. T his
colour refi s in a confiderable degree the adlion of the
air, but in point of permanency is much inferior to that
which is obtained from the ufe of madder.
Sect. III. Of the Mixture of Yellow and Red, cr
Orange.
394. Orange is the ufual refult of a compofttion of
yellow and red colours, but an almo'l endlefs variety
of (hades may be produced, according as we vary the
proportion of the ingredients, and the particular na¬
ture of the yellow made ufe of. It is femetimes the
pradlice of dyers to combine blue with yellow and red,
the refult of which is the colour denominated olive.
Many varieties may be obtained from the ufe of weld,
faw-wort, dyers-weed, and other yellows, and by em¬
ploying tartar, alum, fulphate of zinc, or fulphate of
I N G. 453
copper in the bath, or in the preparation of the C°2^d
cloth. 1 v—1 .1
I. Of Dyeing Wool Orange.
395. By a procefs exaftly the fame as that which is
followed in communicating to (luffs a fcarlet colour, p,-QCefs.
an orange may be given to wool} but the quantity of
red mud be diminiihed, and that of the yellow increaf-
ed. If wool is dyed a red colour by means of madder,
and afterwards yellow with weld, the refulting com¬
pound is a cinnamon colour, and the moil: proper nmr-
dant in this cafe is a mixture of alum and tartar. The
(hades may be varied at pleafure by fubflituting other
yellow dye fluffs inftead of weld, and by varying the
proportions as circumftances may require. . W ool may
receive a reddiih yellow colour by paffing it through a
madder bath, after it has undergone the ufual procefs
for yellow, which has already been defcribed. The
llrength of the madder bath is always to be proportion¬
ed to the (hade required. Braiil-wood is fometimes
employed with yellow fuoftances, or mixed with co¬
chineal and madder. Snuff, chefnut, muik, and other
(hades are produced, by lubllituting walnut-tree root,
walnut peels or fumach, for weld.
II. Of Dyeing Silk, Orange, fa'c.
396. Logwood, bralil-wood, and fuilic, communi*Maroae,
cate to lilk a marone and cinnamon colour, together
with all the intermediate (hades. The (ilk is fcoured
in the ufual manner, alumed, and a bath is prepared,
by mixing together decodlions of the three different
woods mentioned above, made feparately, varying the
quantity of each according to the (hade intended to be
given ; but the proportion of fuftic (hould be greateil.
The (ilk is turned in the bath on the (kein (licks,
and when it is taken out, if the colour be unitorm,
it is wrung and again dipped in a (econd bath of
thefe three ingredients, according to the effed pro¬
duced by the firft, in order to obtain the (hade re¬
quired.
397. The blue vat is not made ufe of, when an Ctfive.
olive colour is to be communicated to filk. Alter be¬
ing alumed, it is dipped in a bath of weld, which is
made very ftrong. To this is afterwards added the
juice of logwood, with a (mall quantity of folution of
alkali when the lilk is dipped. This converts it into
green, and gives the olive colour. It is dipped again
in this bath till it has acquired the (hade wanted.
398. To communicate to it the colour known by
the name of rotten olive, fuftic and logwood are added
to the bath after welding, without any alkali. 11 the
colour wanted is to incline more to a red, the addition
of logwood alone is futficient. A fort of reddifli olive
may likewife be obtained, by dyeing the (ilk in a luf-
tic bath, to which a greater or .leffer quantity has been
added of fulphate of iron and logwood.
III. Of Dyeing Cotton and Linen Orange, iffc.
399. A cinnamon colour is communicated to thread Cinnamon
and cotton, by commencing the procefs for dyeing co.our.
them with verdigrife and weld ; they are afterwards to
be dipped in a folution of fulphate of iron, denominated
by the French bain d'af/ii’ age, and then wrung cut and
dried, As focn as they are dried, they are galled in
. the
454 , DYE
Compound the proportion of three obnces to the pound of ftuff j
. C° °urs* . then dried again, alumed as for red colours, and mad-
dered. After being waflied and dried, they are put
into hot foap-ftids, and turned till they have acquired
a fulhcient degree of brightnefs. It is the pradlice
of fome dyers to add to the aluming a decodtion of
fuftic.
Olive. 400. By boiling four parts of weld and one of potafh
in a fufficient quantity of water, M. d’Apligny informs
us, a fine olive colour is communicated to cotton and
thread. Bralil wood which has betn fteeped for a
night, is boiled feparately with a fmall quantity of ver-
digrife, and thefe folutions are mixed together in vari¬
ous proportions, according to the particular (hade re¬
quired. The thread or cotton is dipped in the com¬
pound folution in the ufual way.
Sect. IV. Of the Mixture of Black with other Colours.
Brown, The compound colours which are obtained from the
mixture of black and other colours, are brown, gray,
drab, &c. according to the nature and proportions of
ihe fimple colours employed.
I. Of Dyeing Woollen Stuffs Brown, Gray, &c.
401. To give a browning to cloth, as foon as it has
been dyed, it is dipped in a folution of fulphate of iron,
with the addition of an aftringent, which makes a black
bath. It is more common to mix a fmall quantity of
folution of iron with a bath of water, adding more till
the dyed ftuff dipped in it has received the intended
(hade. Sulphate of iron is fometimes added to the dye
bath *, but by dipping the dyed ftuff in a folution of
this fait, the end is more eafily attained. It is the
ufual pradlice of M. Poerner to foak the ftuff in a folu¬
tion of fulphate of iron, to which other ingredients are
fometimes added, and after having taken it out of the
moi'dant, it is dipped in the dye bath.
Coffee co- 402. In order to obtain coffee and damafeene co-
lour. lours, with other (hades of browns of the common dye,
the firft method is adopted j a colour more or lefs deep
is communicated to them, according to the (hade in¬
tended to be obtained by the browning j and a bath is
made of galls, fumach, and alder bark, with the addi¬
tion of fulphate of iron. Thofe (luffs are firft dipped
to which the lighted (hades are to be communicated,
and when thefe are finifhed, the browner ones are dip¬
ped ; a quantity of fulphate of iron being added
for each operation, proportioned to the effed intended
to be produced.
Gray. 403* Blueifti grays are communicated to (luffs, ac¬
cording to Poerner, by the folution of indigo in ful-
phuric acid, combined with a mixture of decodion of
galls and fulphate of iron, varying the (hades according
to the different quantities of thefe ingredients made me
of. If to a bath compofed of cochineal, fuftic and galls,
fulphate of iron be added, other (hades are obtained.
404. For marone, and fuch other colours as bear a
ftrong refemblance to it, faunders and galls are em¬
ployed, and fometimes a browning, with the addition
of logwood. If dyed in the remains of a cochineal
bath, thefe colours may be made to incline to a crim-
fon or purple, and the fame effed is produced by add¬
ing a fmall quantity of madder or cochineal to the
I N G. Part II.
bath. A little tartar gives a greater degree of bright- Compound
nefs to the colour. With a mixture of galls, fuftic, and , t-olours- ^
logwood, and a greater or fmaller quantity of madder, Hazej>
with the addition of a little alum, thofe colours may be
communicated to (luffs which are known by the name
of hoxel.
405. M. Guhliche produces what is called a puce co-Puce co¬
lour, by boiling for fifteen minutes a pound of woollen ^our'
ftuff with two ounces of alum, a certain proportion of
vinegar and folution of iron, after wiiich he leaves it
in the mordant for twelve hours. He then makes a
bath with the decodion of two ounces of white galls
carefully poured off from the fediment, and mixed
with four ounces of madder, in which, when it grows
hot, the (luff is immerfed, after being taken out of the
mordant, allowing it to remain there, while the tem¬
perature is gradually increafed, till the colour intend¬
ed has been imparted to it j after which it is boiled
for twTo minutes, wafhed, and dried in the fun. The
colour thus obtained poffefles a great degree of dura¬
bility. It is of a deeper brown by the omiffion of
the alum and vinegar in the mordant $ and after thefe
Colours the lighter (hades are dyed. Sumach may
be employed as a fubftitute for half of the madder.
Different browm colours poffeliing coniiderable per¬
manency, may likewife be produced by the ufe of bra-
fil and logwood, if more or lefs of a foluticn of iron
be mixed with a deco£lion of thefe fubftanees. The
wool being previoully alumed and galled, is dyed
in it.
II. Of Dyeing Silk with Mixtures of Black, &c.
406. M. Guhliche imparts to filk a purple violet Purple vie-
without a blue ground, with a mixture of one part offt*1
galls diffolved in white wine, with three parts of water,
in which a pound of filk is macerated for twelve hours,
foaked in a mordant made up of two ounces of alum,
one ounce of folution of tin, and half an ounce of mu¬
riatic acid. After wringing the ftuff, it is dyed in a
bath compofed of two ounces of cochineal and a fmall
quantity of folution of iron, till the intended (hade
has been ’‘communicated •, and for (hades which are
lighter, the refidua of thefe baths are fufficient, eithef
feparately or mixed together. Madder may be ufed
in the fame vvay, macerating a pound of filk in a folu¬
tion of alum, mixed with an ounce of muriatic acid,
and a quantity of folution of iron. When the fluff' is
wrung out, it is dyed in a bath made of eight ounces
of madder. When deeper colours are wanted, fome of
the folution of galls in white wine is mixed with the
madder and cochineal baths.
407. Silk may be dyed in a bath made of equal
parts of brafil and logw’ood juice, adding a certain
quantity of folution of iron, after the (luff has been
foaked in a folution of twro ounces of alum, and an
ounce of muriatic acid. If folution of galls be added,
the colour becomes deeper.
Colours refembling that of brick, may be produ-Brick ce»
ced, by immerling ftlk in an anotta bath, after prepar-lour.
ing it with a folution of galls mixed with a certain
quantity of folution of iron. By the mixture of bra¬
fil, logwood, archil, and galls, and by a browning
with fulphate of iron, a number of different (hades are
produced \ but the whole of them have more or lefs
■a
Chap. III. DYEING.
Calico- a tendency to fade, although their brightnefs is very
Printing, pleafing to the eye.
HI, Of Dyeing Silk with Mixtures of Black, &c.
With black 408. A permanent violet colour may be. given to
calk. thread and cotton, when fcoured in the ordinary way,
by preparing a mordant with two quarts of the bath
of what is called the Hack cajk, and four quarts of wa¬
ter for each pound of fluff, which is made to boil, ^d
the fcum is removed which forms on the iurface, till it
■wholly difappears. The liquor is poured into a vat, and
when warm, four ounces of fulphate of copper and one
ounce of nitre are diffolved in it. 1 he fkeins are left
to foak in it for ten or twelve hours, wrung out, and
dried. If it is required to produce a deep violet co¬
lour, two ounces of verdigrife muh be added to the
bath •, and if the nitre be omitted, the colour becomes
ftill deeper by galling the thread more or lefs, prior.to
its being put into the mordant. If the nii-re be in-
creafed, and the fulphate of copper diminilhed, the
violet colour becomes more inclined to lilac. A num¬
ber of various fhades may be produced, by different
modifications of the mordants employed.
Marone 409* Cotton is galled, dipped, and wrought in the
•colour. common way, when different {hades of marone colour
are wanted. To the bath employed mull be added
more or lefs of the liquor of the black calk.. T he cot¬
ton is then walked in a bath mixed with verdigrife, next
welded, and dyed to a fuftic bath, to which a folution
of foda and alum is fometimes added. When the cot¬
ton prepared in this manner has been thoroughly waffl¬
ed, it is next well maddered, dipped in a weak folution
of fulphate of copper, and lafl of all in foap fuds. .
Hazel. 410. For fome hazel and fnuff colours, a browning
is communicated to fluffs by means of foot, after the
welding and madder bath, to which galls and fuflic
have been added j fometimes foot is mixed with this
bath, and a browning is likewife imparted by means of
a folution of fulphate of iron j. and for browning co¬
lours, walnut peels are fometimes employed as a fub-
flitute for folutions of iron. For fuch wools as are de-
figned for the manufafture of tapeftry, they are very
advantageous, becaufe the colour is not changed into
yellow by expofure to the air, as is the cafe in brown¬
ing which is imparted by means of iron j but remains
a confiderable time without any fenfible change. The
hue is indeed rather dull *, but its goodnefs and very
moderate price are fufficient to recommend, a more ex-
tenfive ufe of it for grave colours, which in common
Huffs are fometimes fafhionable.
Chap. III. Of Calico-printing.
Hiitory.
411. This may be denned to be the art of communi¬
cating different colours to particular fpots on the furface
of cotton or linen cloth, while the reft of the fluff re¬
tains its original white colour.
The wonderful and truly ingenious art of calico-
printing feems to have been firfl known in India, and
for more than twro centuries before the commencement
of the Chriflian era. Although the Egyptians were
wrell acquainted with this art in the days of Pliny, as
he himfelf informs us, it can fcarcely be doubted that
they derived the knowledge of it from India, as that
2-
45*
country rather than Egypt, produced the colouring and pCalico.
other materials for carrying it on. If we con.idei i.s _i—'
prefent improved Hate, the elegance of different pat¬
terns, the beauty and durability of .the colours winch
can now be imparted to cotton or linen.fluffs,. and the
difpatch with which the various operations of this art
are condusfted, we mull be aflonifhed at the rapidity ol
its improvements, when we recollett that it has been
known in Europe for little more than a century. Per¬
haps no other art has rifen to fuch perfedlion in lo fhort
412. Our readers will not eXpedl that our account of
this fubieft fhould be tedious or elaborate, fince the.artift
is prefumed to be already acquainted with the different
proceffes which are employed in calico-printing •, and to
fuch as wifh only for a general knowledge of the art,
in a theoretical point of view, prolixity would be diia-
greeabltn ^ ^ 0f caiico_printing confifts in impregnating Nature of
with a mordant, fuch parts of cotton or. linen fluffs asthis art.
are to have particular colours communicated to them,
and then dyeing them in the ufual manner with lome
colouring fubflance. Thofe parts of the cloth only which
receive the mordant are intimately united with the co¬
louring matter, although the whole furface muft be
more or lefs tinged j but the parts which have not ic
ceived the mordant are reflored to their original bright-
nefs by means of waffling, and afterwards bleaching it
upon the grafs for fome days, taking care to turn the
wrong fide towards the fun. If red flripes are to be
communicated to a piece of white cotton cloth, thofe
parts of its furface on which the flripes. are intended to
appear, are marked out by a pencil dipped in acetate
of alumina ; after which it is dyed with mackler in the
ufual way. ^Tien it is firfl taken out of the dyeing
veffel, its whole furface is red, but when it is wafhed
and bleached, it refumes its original whitenefs, the
ftripes only excepted which, being impregnated with
the acetate of alumina, remain red. By a fimilar pro-
cefs may yellow or any other flripes be fixed upon cot¬
ton or linen, by the fubflitution of quercitron bark,
weld, &c. in the room of madder.
414. When different parts of the cloth are to receive To cornmn-
different coloured flripes at the fame time, different mor-nicate dif-
dants muff be employed. If ftripes. are delineated on ^ours>
its furface with the acetates of alumina and iron, and
if it be then dyed with madder in the ordinary w ay, it
will, after being waffled and bleached as formerly di-
refted, exhibit itripes of a red and brown colour. If the
fame mordants are employed, but quercitron bark ufed
inflead of madder, the ftripes will then be yellow, and
olive or drab.
415 . The mordants known by the names of acetate of ufual mor-
alumina and acetate of iron, wdiich are made ufe of in dants.
calico-printing, may either be applied to fluffs with a
pencil, as already mentioned, or {till more expeditioufly
by means of blocks, on which the intended patterns are
cut. Being defigned only for particular parts of the
furface of the cloth, great caution is neceffary to pre¬
vent them from fpreading to any part of it which is to
remain white, and to prevent their interference when
the application of more than one is required. Such a
degree of confiflence muff of confequence be given to
the mordants employed, as will prevent this difagre&-
able effe6t, which cannot fail to deilroy the beauty.
and.1.
DYE
and elegande of the print. If blocks are to be made
ufe of, the mordants may be brought to a proper
confidence by means of it arch ; but gum arable muit
be mixed with them, when the pencil is to be
employed. The thicknefs ihould not exceed wdiat
is abfolutdy neceffary to prevent the mordants from
fpreading j oecaufe, if carried too far, the cotton is
frequently not faturated with the mordant, in con-
lequence of which the dye is but imperfectly communi¬
cated.
416. To diftinguith thofe parts of the cloth which
are impregnated with mordants, it is a common
practice to give the mordants fome particular tinge
by which they may be known ; and for this pur-
pofe printers commonly make ufe of the decobtion of
bralil wood. Dr Bancroft objebts to this prabtice,
becaufe he is of opinion that the procefs of dyeing
is impeded by the colouring matter of brafxl wood.
ofth^emorn ^ ^ a®n’!ty t^ie dye fluff for the mordant dif-
-dant.6 m°r P\aces the colouring matter of the brafil wood j and
without fuch affinity it would be impoffible to ftrike the
colour. Some of the dye-fluff to be employed after¬
wards is recommended by Dr Bancroft for colouring
the mordant, who prohibits the me of a larger quantity
than what is fufficient to render it diftinguilhable when
an application of it is made to the cloth. Should too
large a quantity b^ united with the mordant, a confi-
derable proportion of the latter would be combined
with colouring matter, by which means its affinity for
the cloth would be diminiffied, and therefore a perma¬
nent colour could not be expebled to refult from fuch a
partial combination.
bedded11** ^ nece^ary to ^ry t^e doth completely after
L “ ’ . the application of the mordants, for which purpofe artifi¬
cial heat may be employed, which has a tendency to
promote the feparation of the acetous acid from its
bafe, and affift its evaporation, and thus the com¬
bination of the mordant with the cloth will be faci¬
litated.
and then 418. When the cloth is thoroughly dried, it is cufto-
w afhed. maiy tQ wadi it with warm water and cow-dung, till every
particle of the ftarch or gum arabic which had been
employed to give a proper conliltence to the mordants,
and thofe parts of them which do not combine with
the cloth, are entirely removed. The loofe particles
of the mordant are entangled by means of the cow-
dung, and prevented from being attached to thofe parts
of the cloth which are to remain white. After this, it
muff be completely rinfed in pure water.
Colouring 4IQ. Indigo, madder, quercitron bark, and w^eld, are
oloyed^111"^16 dying ingredients made ufe of by calico-printers}
but the lad of thefe is feldom ufed by the. printers of
. this country, except for the purpofe of communicating
yellows of a delicate greenifh ihade. Quercitron bark,
on account of its inferior price, and capacity of impart¬
ing colours equally good, as well as requiring a lefs
degree of heat, is employed as a fubditute. It is ufual
to apply indigo at once, either by means of the block
or pencil, becaufe it requires not the intervention of a
mordant to fix it. Tins preparation is made by boiling
together indigo, potadr reduced to the caudic date by
means of quicklime, and orpiment; afterwards thicken¬
ing the folution with gum. Dr Bancroft recommends
the ufe of coarfe brown fugar as a fubditute for orpi-
gnent, which operates as powerfully in the decompofi-
1
I N G.* Part II.
tion of the indigo, and in promoting its folubility, Cafico-
anfivering at the fame time all the purpofes of gum. Printing.
420. When the cloth is thoroughly cleanfed after itD7~^
has been impregnated with the mordant, the dyeing pro- in-uCtif.
cefs is conducted in the ufual manner. As the whole
of it receives a tinge of the dye, it mud be completely
w'adred and bleached for fome days on the grafs, as for¬
merly mentioned, by which means the colour is en¬
tirely removed from thofe parts of the cotton not
impregnated with the mordant, while all the other
parts of it retain the colouring matter as powerfully as
at firft.
421. One of the moll common colours imparted to Nankeen
cotton prints is a fpecies of nankeen yellow of different ye^ow> &~c‘
lhades, and for the mod part in ftripes or fpots. It is
produced by means of a block on which is cut the intend¬
ed pattern, rubbed over wuth acetate of iron brought to a
proper confidence with gum or darch, and applied to
the cotton j which, being dried and cleanfed in the ordi¬
nary way, is immerfed in a ley of potaffi. It is proper
to obferve, that the quantity of acetate of iron mud be
proportioned to the particular ffiade required.
422. In order to produce a yellow colour, the block is Yellow,
rubbed over with acetate of alumina ; and the cloth,
after being impregnated with this mordant, is dyed
with quercitron bark in the common manner, and then
bleached.
423. If madder be fubdituted for the quercitron bark, Red.
a red colour is given to cotton by the fame procefs.
4 24. To communicate to duffs the fine light blue colours Blue,
which we frequently behold upon cotton, the block is
rubbed over with a compofition confiding partly of
wax, by means of which all thofe parts of its fur-
face are to remain white. It is next dyed in a cold
vat of indigo, and wffien it is dried, the wax compo¬
fition may be removed by the ufe of hot water.
425. Lilac and blackilh brown colours are communi- Lilac, See,
cated by acetate of iron, proportioning the quantity to
the particular Ihade required, and adding a little fu-
mach for fuch lhades as are to be very deep. The cot¬
ton is .then dyed with madder, and bleached in the ufual
manner. Dove colour and drab are produced by means
of acetate of iron and quercitron bark.
426. When a variety of different colours are to be How to ap-
madeon the fame print, a greater number of operations ply differ-
are unavoidably neceffary. Upon each of the blocks toent co^our5»
be employed is cut that particular part of the pattern
which is to have one appropriate colour •, and wffien thefe
blocks are rubbed over with their refpeclive mordants
and thus applied to the cloth, the dyeing procefs is af¬
terwards conduced in the ordinary manner. If, for ex¬
ample, three different blocks are to be made ufe of, the
firft rubbed over with acetate of alumina brought to a
proper confiftence, the fecond with acetate of iron, and
the third with a compofition of thefe two, the colours
refulting, after the dyeing and bleaching proceffes are
finiihed, will be the following.
Acetate of alumina yellow,
iron olive, drab, dove.
From the compound olive green, olive.
It is proper to ohferve, that thefe are the refults when
quercitron bark is employed > but by the fuhftitution
of madder the following colours will be obtained.
Acetate
Chap. III.
Calico-
Printing.
Acetate of alumina
iron
From tlie compound
DYE
red,
brown, black,
purple.
When it is required to produce at the fame time both
thofe colours which are imparted by madder, and like-
wife by the ufe of quercitron bark, mordants are firft
applied for one part of the pattern, after which the cot¬
ton is dyed in a bath of madder, and then bleached.
The reft of the mordants are then applied in a flmilar
manner, after which the cotton is dyed with the quer¬
citron bark, and bleached as before. Ihe colours
which the madder communicates are very little affected
by the fecond dyeing, becaufe the mordants by which
their permanency is fecured, are previoully faturated.
A new mordant may be applied to fome of the colours
refulting from the ufe of madder, by which means they
receive a new durable colour from the bark. And by
means of the indigo liquor other new colours may ftill
be communicated after the laft bleaching.
Variety of 427. The following colours may be communicated
colours by to cotton, by means of the different proceffes which
process. have been Scribed.
Madder Dye.
Acetate of alumina
iron
Ditto diluted
Mixture of the twT0
red,
brown, black,
lilac,
purple.
Bark Dye.
Acetate of alumina yellow,
iron dove, drab,
Lilac and acetate of alumina olive,
Red and acetate of alumina orange.
Indigo Dye.
Indigo blue,
Indigo and yellow green.
Thus may twelve different colours be communiQfited
to the fame print by thefe different proceffes.
Colours for 428. If durable colours could be directly applied to
penciling. cotton by means of the block or pencil, without the
help of mordants, nothing could be conceived more
ftmple than the art of calico-printing but with the
fingle exception of indigo, the communicating of per¬
manent colours requires the procefs of dyeing. Yellow,
indeed, which is a compound colour, and fome others,
may be communicated to cotton at once, by mixing
together an infufton of quercitron bark and acetate of
alumina, while the fame mordant with a decodtion. of
madder, imparts to it a red colour j but thole which
are produced in this way are far from being durable,
fince they are deftroyed by walhing, and fometimes
even by expofure to the air.
429. But as it is not always pradticable for calico-
printers to avoid the application of colours in this man¬
ner, every endeavour to give them a greater degree of
permanency becomes an objedf of importance. I he
following compolition has been recommended for a
Compofi- yellow printing colour. Three pounds of alum, and
tien for yel-three ounces of pure chalk are to be diffolved in a gal-
iow colour. jon q£ hot water, to which are to be added twro pounds
of acetate of lead. This mixture is to be occalionally
Vol. VII. Part II.
I N G. . . 457
ftirred for 24 or 36 hours, after which it is to remain
at reft during 1 2 hours. I he clear liquor is then to , —i
be poured off, and as much more hot water added to
the refiduum, as will, after being ftirred and allowed
to fettle, amount to three quarts when added to the
firft quantity. Into a tinned copper veffel put fix
pounds, or at mo ft a quantity not exceeding eight
pounds, of quercitron bark fufficiently ground, and boil
it for an hour in four or five gallons of clean foft wa¬
ter, adding afterwards a little more water if the bark
is not properly covered. When the liquor is thorough¬
ly boiled, let it be removed from the fire, and left to
fettle for half an hour, when the clear decoftion is to.
be poured off through a fine fieve. Six quarts more ot
pure water are then to be put upon the fame bark, and
boiled for a quarter of an hour, being previouily wrell
ftirred. When it has flood a fufficient time to fettle,
the clear liquor is to be ftrained off, and being mixed
with the former, both are put into a fhallow wide vef¬
fel to be evaporated by boiling, till the whole, in addi¬
tion to the mordant qlready mentioned, and the gum
or pafte for bringing it to a proper confiftence, does
not exceed three gallons. It will be proper not to add
the three quarts of aluminous mordant till the decoc¬
tion has been cooled dowm almoft to the natural heat
of blood. Lot gum arabic or gum fenegal be taken
for thickening, if the pencil is to be ufed, and ftarch
or flour when blocks are to be employed.
430. If a pound of murio-fulphate of tin be ufed as For bright
a fubftitute for the aluminous mordant in the compofi- yelk*w-
tion defcribed above, a mixture will be produced which
is capable of imparting to cotton a very bright yellow,
and confiderably permanent.
431. A cinnamon colour poffeffed alfo of a fuffi- Cinnamon
cient degree of permanency may be given to cotton,co our‘
by means of a mixture of fulphate of tin and a decoc¬
tion of the quercitron bark.
432. If the decodlions of this bark and of logwood Green,
are boiled together, and proper quantities of fulphate
of copper and verdigrife added to them, together wath
a fmall proportion of carbonate of potalh, there refults
a compound which communicates to cotton a green co¬
lour. Although the expectations of Dr Bancroft were
not fully anfvvered by the trials which he made of this
fubftance, he deemed his fuccefs fuflicient to encourage
him to a farther inveftigation of it.
433. A permanent drab colour may be given to cot- Drab ami
ton by means of acetate of iron mixed with a decoCtion
of quercitron bark, and reduced to a proper confiftence.
This mixture will alfo produce an olive, if added to
the olive colouring liquor already mentioned } and the
colours may be made It ill more permanent ; if a folu-
tion of iron in diluted nitric or muriatic acid be ufed as
a fubftitute for iron liquor. They ought, however, to
be ufed fparingly and with caution, that the texture of
the cotton or linen to which the ware applied may not
be injured.
434. Dr Bancroft made a number of experiments Colours
with the decodion of quercitron bark, to afeertain its *rom ditfe-
effeCls when combined with different metallic lalts as
mordants. 1 he fulphate, nitrate, and munate of zinc, querci-
withthis deco&ion, yielded brownifh yellow colours of iron bark,
different flrades } but none of them were, found. fufti-
ciently permanent when they were applied topically
to linen' or cotton. Mercury in the different acids pro-
3 M duced
thod of
Dyeing
Red.
458 DYE
Indian Me- duced with tlie decoftion of bark different flrades of
brown or yellowifli brown colours j but they did not
prove more durable than the former. The nitro-mu-
riate of platina with a proper proportion of decoftion
of quercitron bark, afforded, when topically applied to
linen or cotton, flrong full-bodied fnuff colours, which
were found fufficiently permanent, and capable of re¬
filling the affion of acids, and of the fun and air. Ni¬
trate of filver with a decoclion of the bark, when ap¬
plied topically to linen or cotton, produced ftrong dark
brown and cinnamon colours of confiderable durability.
Nitrate of lead with the fame deception gave by topi¬
cal application a drab colour which was not lefs dura¬
ble than the former. Nitrate of bifmuth produced with
the decodlion of bark a very full and flrong browniih
yellow. This colour, however, is attended with the in¬
convenience of becoming almofl black when expofed
to the action of the alkaline fulphurets, fulphurated
hydrogen gas, or even by the adlion of common foap.
Muriate of bifmuth with the decoction gives a drab co¬
lour j fulphate of the fame metal affords a yellow •, but
thefe colours wrhen applied to cotton or linen are not
durable. Nitro-muriate of antimony produced with
the decodlion of bark fomething of a fnuff colour, which
applied to linen and cotton pofleffes fome degree of du¬
rability. Nitrate and muriate of cobalt with the quer¬
citron bark gave different fhades of brown ^ but thefe
colours were extremely fugitive j they foon faded by ex-
pofure to the fun and air.
435. The art of calico-printing has been hitherto al-
thod of
Dyeing
Red.
I N G. Appendix:,
moft folely limited to linens and cottons. Many colour- In 'fan Me-
ing matters have fuch an affinity for thefe fluffs that
they readily enter into combination with them at the
ordinary temperature of the atmofphere. This is alfo
the cafe with filk, fo that colouring matters might be
applied topically to the latter by means of fimilar ope¬
rations as to linen and cotton. Attempts, however, Woollen
have been made to extend the procefs of topical dyeing pnn-
or printing to woollen fluffs, and particularly thofete^’
kinds known by the name of kerfeymeres, which are
employed after being prepared in this wray for waillcoat
patterns. When it is recollected that woollen fluffs
when they are to be dyed generally mufl be expofed to a
conliderable degree of heat, it is eafy to conceive that
it will be difficult to communicate fpots or figures by
printing to woollen fluffs. The means by wrhich this
difficulty is obviated in thofe manufactories where this
operation is conducted have been hitherto kept fecret.
The preparation of colouring matters, whether fuch as
may be employed fimply or require the ufe^of mor¬
dants to fix them, will be eafily underftood from what
wre have already fully detailed in the courfe of this
treatife. The application of the colours is made in the
ufual way ; and it is faid that, after the woollen fluffs
are printed, they are wrapped up in two or three folds
of thick paper, to prevent the accefs of moiflure which
might caufe the colours to run, and expofed to the
fleam of boiling water for fuch a length of time as
may be fuppofed neceffary for the colouring matter to
combine with the fluffs f.
f Bancroffr
185.
A P P E
After that part of the preceding treatife to which it
properly belongs, was printed off, the following ac¬
count of the Indian method of dyeing cotton cloth and
cotton thread a red colour came under our notice. It
tvas communicated to the fociety for the encouragement
of arts, &c. by Mr Maclachlan of Calcutta. The in-
fertion of it may perhaps excite the curiofity of fome of
our countrymen to farther inquiries into the ft ate of
this as well as of other arts in India, wffiere, from being
long known and praftifed, many of them have arrived
at a high degree of fimplicity and perfection.
Directions for dyeing a bright Ref four yards of three-
fourths broad Cotton Cloth.
iff. The cloth is to be well walked and dried, for
the purpofe of clearing it of lime and congee, or (larch,
generally ufed in India for bleaching and dreffing
cloths} then put into an earthen veffel, containing
tw-elve ounces of chaya or red dye root, with a gallon
of water, and allow it to boil a fhert time over the
fire.
2d. The cloth being taken out, walked in clean wa¬
ter, and dried in the fun, is again put into a pot with
one ounce of myrobalans, or galls coarfely powalered,
and a gallon of clear water, and allotved to boil to
one half: when cool, add to the mixture a quarter of
a pint of buffalo’s milk. The cloth being fully foaked
in this, take it out, and dry it in the fun.
3d. Wafh the cloth again in clear cold water, and
N D I X.
dry it in the fun ; then immerfe it into a gallon of wa¬
ter, a quarter of a pint of buffalo’s milk, and a quarter
of an ounce of the powdered galls. Soak well in this
mixture, and dry in the fun. The cloth, at this ftage
of the procefs, feeling rough and hard, is to be rolled
up and and beetled till it becomes foft.
4th. Infufe into fix quarts of cold wrater, fix ounces
of red wood lhavings, and allow it to remain fo two
days. On the third day boil it down to two-thirds the
quantity, when the liquor will appear of a good bright
red colour. To every quart of this, before it cools,
add a quarter of an ounce of po-wdered alum ; foak in
it your cloth twice over, drying it between each time
in the (hade.
5th. After three days waffi in clean water, and half
dry in the fun j then immerfe the cloth into five gal¬
lons of water, at about the temperature of 120° of
Fahrenheit, adding 50 ounces of powdered chaya, and
allowing the whole to boil for three hours ; take the
pot off the fire, but let the cloth remain in it until the
liquor is perfectly cool 5 then wring it gently, and
hang it up in the fun to dry.
6th. Mix intimately together, by hand, about a pint
meafure of frelh (beep’s dung, with a gallon of cold
water, in which foak the cloth thoroughly, and imme¬
diately take it out, and dry it in the fun.
7th. Waffi the cloth well in clean water, and fpread
it out in the fun on a fand-bank (which in India is uni-
verfally preferred to a grafs-plat) for fix hours, fprink-
ling
Index, DYE
Jndin.'i Me. ling it froiw tliuc to time, as it dries, with clean water,
thadof for the purpofe of finifiling and perfecting the colour,
^Red'° which will be of a very fine bright red.
Diretfions for dyeing of a beautiful red, eight ounces of
Cotton Thread.
111. Put one gallon and a half, by ineafure, of fap-
wood allies, into an earthen pot, with three gallons of
water, and allow the mixture to remain twenty-four
hours to perfect it for ufe.
2d. Put the following articles into an earthen pot,
viz. Three quarters of a pint of Gingelly oil j one pint,
by meafure, of Iheep’s dung, intimately mixed by hand
in water ; two pints of the above ley.—After mixing
thefe ingredients well, pour the mixture gradually up¬
on the thread into another veffel, wetting it only as
the thread, by being fqueezed and rolled about by the
hand, imbibes it, continuing to do fo until the whole
is completely foaked up, and allow the thread to re¬
main in this date until next day.
3d. Take it up, and put it in the fun to dry 5 then
take a pint and a half of alh-ley, in which fqueeze
and roll the thread well, and allow' it to remain till
next day.
4th. Squeeze and roll it in a like quantity of alh-
ley, and put it in the fun to dry ; when dry, fqueeze
and roll it again in the ley, and allow it to remain till
next day.
5th. Let the fame procefs be repeated three or four
times, and intermit till next day.
6th. Ley the thread once, as the day before, and,
when well dried in the fun, prepare the following li¬
quor : One gill of Gingelly oil; one pint and a half
of alh-ley.—In this fqueeze and roll the thread well,
end leave it fo till next day.
1- N G. 459
7th. Repeat the procefs pf yellerday, and dry thelndian Me-
1 j • T r thod of
thread m the lun. Dyeing
8th. The fame procefs to be repeated. Rp(i
pth. Firlt repeat the alh-ley procefs three or four 1y
times, as under the operations 3, 4, and 5, and then
prepare the following mixture: One pint of Iheep-dung
water •, one gill of Gingelly oil} one pint and a haif
of alh-ley.—In this fqueeze and roll the thread well,
and dry it in the fun.
toth. Repeat the fame procefs,
Iith. Do. Do.
1 2th. Do. Do.
13th. Do. Do.
14th. Do. Do.
15th. Walh the thread in clean water, and fqueeze
and roll it in a cloth until almolt dry •, then put it into
a velfel containing a gill of powdered chaya root, one
pint by meafure of callian leaves, and ten pints of clear
w'ater in this liquor fqueeze and roll it about well,
and allow it to remain fo till next day.
16th. Wring the thread, and dry it in the fun, and
repeat again the whole of the 15th procefs, leaving the
thread to fteep.
17th. Wring it wrell, dry it in the fun, and repeat
the fame procefs as the day before.
18th. Do. Do.
19th. Do. Do.
20th. Wring and dry it in the fun, and with the like
quantity of chaya root in ten pints of water; boil the
thread for three hours, and allow it to remain in the
infufion until cold.
21 ft. Wafli the thread w'ell in clear w'ater, dry it in
the fun, and the whole procefs is completed.
INDEX.
Shun, a mordant for cotton,
how' applied,
Anotta, hiftory of,
properties of,
Apparatus for dyeing filk,
wringing out,
raking,
giving a ground,
dipping,
Archil, hiftory of,
properties,
lingular change of,
Arts, origin of,
when loft,
revived in Italy,
Afracan, procefs for dyeing cotton
red at,
mordant ufed at,
madder dye, how prepa¬
red at,
N° 211
222
248
247
*33
136
137
138
139
171
172
*73
2
16
17
223
224
227
B.
Bancroft, Dr, his procefs for dyeing
fcarlet, 200
advantages of it, 202
for blue, 314
pruflian blue, 323
Bath, preparation of, for dyeing wool
yellow, _ 255
cotton and linen, 277
BertholleCs experiments for trying the
permanency of colours, 61
Betula alba, bark of, for dyeing brown, 3 57
Birch, bark of, ufed in dyeing brown, ib.
Black, the fubftances ufed for dyeing, 3 26
procefs employed for, 330
Hellot’s procefs for, ib.
common procefs for, 331
cheaper procefs for, 332
procefs of the Engliih dyers
for, 333
Blue, how to dye wool, 292
accidents which may happen
in the dyeing of, 293
how communicated in calico-
printing, 424
Bodies, affinity of, for certain rays
the caufe of colour, 41
Bodies, white, effefl of colours on, N° 45
coloured, are compounds, 53
Boilers, what kind of, beft for dyeing, 192
Brazil wood, hiftory of, 178
properties, 179
Brown, fubftances ufed in the dye¬
ing of* . 351
properties of, 352
advantages, 353
c.
tldrons for dyeing, 132
ilico-printing, hiftory of, 411
nature of, 4Z3
different colours how
communicated, 414
mordants ufed, 415
application of, 41^
cloth waffied, 418
and dried, 417
indie light, cffefls of, on fcarlets
differently dyed, 203
irthamus, hiftory of, 174
preparation of,
n M 2
*75
f'nrth/lnui <•-
460
Carthamus, properties of, N° 176
Chamomile, ufe of, in dyeing, 251
Chemi/lry, importance of, in dyeing, 150
Cherry-red, how obtained, 215
Cochineal, hiftory of, 160
varieties of, 162
attempts,to cultivate, 164
properties of, 165
Colours, nature of, 29
divilion of, 151
fimple, 152
caufe of, explained, 30
durable, 267
Newton’s theory of, 33
objeftions to, 36
fupported, 34
inconfiflent
♦ writh facts, 37
of metals independent of
denfity, 39
changes of, 42
from new combi¬
nations, 43
change of, produced by oxy¬
gen, # 54
compound, explanation of, 364
how to try the permanency
of, 56
green, 376
violet, 393
olive green, 377
for penciling, 4 29
Cotton, origin of, 117
ftrufture of, 118
affinity of, for colouring matter, 119
preparations for dyeing, I 20
aluming, 121
galling, 122
procefs for dyeing madder or
Turkey red, 217
at Aftracan, 223
the Grecian method, 231
by Papillon at Glaf-
gow, 238
by Haufsman, 239
fcarlet with cochi¬
neal, 241
crimfon, 24 2
how dyed blue, 304
black, 346
green, 376
olive green, 377
violet, 393
Crimfon, how dyed by one procefs, 208
by the conver-
fion of fcarlet, 209
D.
Dove-colour, dyeing wool, 382
Drab-colour imparted to cloth by a-
cetate of iron, 426
Dufay's experiments for trying the
permanency of colours, 57
Dyeing, definition of, I
origin of, 3
DYEING.
Dyeing, hiftory of, N° 4
progrefs of, ib.
among the Indians, 5
Greeks, 6
Jews, 7
Egyptians, 8
revived in Italy, 18
introduced into France, 19
encouraged there, 22
reftraints impofed on, 23
Hate of, in Britain, 25
improved by chemiftry, 26
authors on the art of, 27
operations for, 130
E.
Englifh blue, how produced, 318
green, 374
Euler, proof adduced by, that the co¬
lours of bodies do not origi¬
nate from reftection, 46
Fenugreeh, ufe of, in dyeing, 252
Flax, origin of, 1 24
how watered, 1 25
ftrufture of, I 27
prepared for dyeing, 1 28
French berries, ufe of, in dyeing, 252
Fuflic, hiftory of, 246
properties of, 247
G.
Galling, ufes of, 219
remarks on, 220
Grecian method of, 234
Gray, a compound of black and o-
ther colours, 366
Green, a compound of blue and yel¬
low, ib.
various (hades of, 367
fubftances for dyeing, ib.
Saxon procefs for dyeing
wool, 369
for dyeing
filk, _ 372
Engliffi procefs for dyeing
filk, 374
H.
Hauffman, Mr, his procefs for mad¬
der red, 239
F[a%cl colour, how produced, 410
HelloCs experiment for trying the
permanency of colours, 60
procefs for dyeing with in¬
digo, _ 299
Hiccory, ufe of, in dyeing, 252
Houfes for dyeing, 131
Indigo, when firft ufed, 20
in Europe, 283
different fpecies of, 284
how prepared, 285
Index.
Indigo, different qualities of, N° 286
from what obtained,- 287
properties of, 289
ufed in two dates, 290'
Ingredients, proportion of, for red¬
dening fcarlet, 189
Iron, oxide of, as a mordant, ' 95
folution of, for the fame, 74
how prepared, 349
K.
Kermes, hiftory of, 167
properties of, 168
Kufler brings the oxide of tin to Lon¬
don, 88
L.
Lac, hiftory of, 169
properties of, 170
Light, nature of, 28
Lilac, how communicated to cloth in
calico-printing, 425
Lime, ufe of, in dyeings 83
precautions in the ufe of, 296
Linen, dyed yellow with weld, 273
blue, 304
black, 346
procefs followed at Manchef-
ter for, 348
how dyed violet, 393
cinnamon colour, 399
olive, 400
dyed red with madder, 2x7
Liquor, purple, formed in fnails, 15
Logwood, hiftory of, 183
properties of, tb.
M.
Madder, preparation of, 156, 184
procefs for dyeing with, 182
roling, 183
properties of, 159
Marrone colour, how produced, 409
Matters, coloured, do not reflect light, 44
proof of this, 45
animal, ufed as mordants, 97
animal and vegetable, 103
coloured black by incident
fight, _ . 47
Metallic oxides, ufe of, in dyeing, 84
Mordants, definition of, 66
importance of, 67
how applied, 69
effe£ts of, explained, 70
various ways applied, 100
for dyeing cotton red, 218
ufed in dyeing black, 3 29
Muflorooms, ufe of in dyeing, 272
N.
Nankeen, colour how to dye, 279
another procefs for, 280
how done in the eaft, 281
how communicated in cali¬
co-printing, 421
Index.
o.
Olive, communicated to cloth in ca¬
lico-printing by acetate of
iron, N° 426
and by the acetates of alumina
and iron combined,
Orange colour, how produced, 271
a compound of red and yel-
low, 366
various (hades of 394
P.
Papillon Mr, his procefs for dyeing
red, 238
Penciling, colours for, 429
Platiere, De la, his method of dye¬
ing with Pruffian blue, 3 22
Poppy-red, how obtained, 214
Procefs for dyeing wool yellow, 258
Pruffian blue, how to dye -with, 3 20
Purple, Tyrian, celebrated by the
antients, 9
a compound of red and yel¬
low, 366
liquor, preparation of, 9
fluffs how prepared to re¬
ceive,
permanency of 10
high price of, 11
worn by the Romans, 1 2
ftill u(ed in dyeing, 13
found in fnails, 15
&•
Quercitron bark, hiftory of, 248
properties, 249
for dyeing wool
yellow,. 257
R.
Red fubftances for dyeing, 155—180
how to obtain different (hades of, 195
madder, for cotton, 217
Grecian method of ob¬
taining, _ 231
how improved in the
Levant, _ 237
how communicated in
calico-printing, 423
Rofe-colour, how obtained, 2x6
Rouge, preparation of, I77
madder, for wool, 18 2
(ilk, _ 211
cotton and linen, 217
fcaflet, 186
crimfon, 208
S.
Salt, common, ufe of in dyeing fear-
let, *96
Sandal wood, ufe of, in dyeing, 358
Saxon blue, difeovery of, 3T3
how to dye with, 3 I4
green, procefs for dyeing wool, 369
dyeing.
Saxon green, procefs for dyeing filk, N° 3 7 2
Scarlet, procefs for dyeing, i87
with cochineal, *97
procefs for boiling, d’-
reddening, 188
how to give a bright red to, 191
a compound colour, 198
different (hades of, _ 20 7
Shell-JiJh, producing a purple liquid, 14
found on the French coaft, in.
method of catching, tb*
Silk, how produced, I11
fcoured, 112
treated when ufed white, 1x3
to extract the colouring
matter of, 115
alumed, 116
procefs for dyeing red, 2X1
with madder, ib.
brazil wood, 2X2
cochineal, 213
weld, 268
how prepared for a blue colour, 301
Turkey blue, 302
black, 336
how galled, 338
foftened, 34°
raw, how to dye, 342
how dyed green, 371
purple, 389
a procefs for dyeing, 392
how dyed olive, 397
purple-violet, 406
brick colour, 407
howT dyed with the black cajlt, 408
Soot, ufe of, in dyeing, . 359
Stuffs to be dyed (hould be white, 51
Sumach, properties of, 35^
ufe of, in dyeing, 362
T.
Terms for different (hades of colour, 140
Tejls for fllks, 62
dye-fluffs, 63
Tin, oxide of, ufed in dyeing, 87
brought to London by
Kufter, 88
folution of, how prepared, 91
acetate of, recommended by
Hauffman as a mordant, 93'
Trefoil, leaves of, ufed in dyeing, 253
V.
Vats, how liable to accidents, 293
recovered, 294
preferved from putrefaftion, 295
made with indigo, 298
for blue, recommended by
D’Apligny-, 3°4
by Quatremere 306
on a large fcale, 3°7
recommended by Bergman, 309
461
Vats recommended by Hauffman, N 310
Velvet, how dyed black, 343
fubftances ufed inftead of galls
for, . 344
Verdigrife, ufe of, inftead of tartar in
dyeing, 2^5
W.
Walnut-peels, for dyeing brown, 35 f
properties of, 352
preparation of, 354
Water, importance of, in dyeing, . 142
different kinds how diitin-
guifhed, *44
method of purifying, 141
tefts for, 145
Weld, ufe of, in dyeing yellow, 244
properties of, _ 245
Willows, fweet, leaves of, ufed in dye-
ing, 252
Wo ad, ufe of, in dyeing blue, 291
Wool, different modes of dyeing, HO
ftrufture of I05
felting of, 10^
how fulled, 107
importance of, 108
dyed red with madder, 182
procefs for dyeing, fcarlet, 186
crimfon, 208
yellow7, 254
blue, 315
brown, 360
black, 330
green, 368
purple, 381
lilac, 382
orange, 395
coffee-co¬
lour, 40 2
gray, 403
puce colour, 405
dyed purple with logwood, 384
procefs for obtaining, 385
Woollen fluffs, printing, 43^’
Y.
Yellow, fubftances employed for dye¬
ing, 244
mordants neceffary for a per¬
manent, 243
with an orange (hade, 259
bright golden, 261
greenilh, 263
pale green, 264
procefs for a cheap, 270
how communicated in calico-
printing, 4 22
produced by acetate of alu¬
mina, _ 426
compofition for, in calico-
printing, 43°
bright, 431
DYNAMICS.
C 462 ]
dynamics.
Introduce i. NAMICS is that branch of phyfico-mathema-
■ t:°n‘ , . tical fcience which includes the abftraft doc-
Definition. trme of moving forces; that is, the nccefTary refults of
the relations of our thoughts concerning motion, the
immediate caufes of motion, and its changes.
Idea of mo- 2. Motion and its general properties are the firft and
tion. principal objeft of mechanical philofophy. This fci¬
ence indeed prefuppofes the exillence of motion; and
vve may confider it as univerfally admitted and recog-
nifed. With regard to the nature of motion, however,
philofophers are greatly divided in opinion. The moll
obvious and limplelt conception of motion is the fuccef-
five application of the moving body to the different
parts of indefinite fpace, which are conlidered as the
place of the body. This idea of motion fuppofes a
fpace whofe parts are penetrable and immoveable } a
do&rine directly contrary to that of the followers of
Des Cartes, w'ho regarded extenfion and matter as one
and the fame thing. To have a diltinct idea of mo¬
tion, it feems requifite to conceive two kinds of exten¬
fion ; the one, wThich is confidered as impenetrable,
and whicjr conilitutes what we properly call matter or
body ; the other, which being limply confidered as ex¬
tended, without taking any other property into ac¬
count, is the meafure of the diffance of one body from
another ; and whofe parts being fuppofed fixed and im¬
moveable, enable us to judge of the reft or rhotion of
bodies. We may therefore conceive bodies to be pla¬
ced in indefinite fpace, whether real or fuppofed ; and
motion as a change in the flate or condition of a body
from one part of fpace to another. We muft indeed
confider motion as a ftate or condition of exiftence of a
body, which would remain till it is changed by fome
caufe ; otherwife wTe could not have any idea of mo¬
tion in the abflradt. From the changes which we ob-
ferve, w’e infer agency in nature; and in thefe chan¬
ges we are to difcover what w-e know of their caufes.
Idea of 3. In mechanical difquifitions, the fimpleft, and at
fpace. the fame time the mod ufual conception of fpace, is
mere extenfion. We think only of the dillance be¬
tween tavo places. The path along which any body
moves in paiTmg from one place or point in fpace to
another, is faid figuratively to be the path defcribed by
that body. Space is confidered by the geometer not
only as having length but alfo breadth. In this cafe it
is called ^.fitrface. But to have a more complete no¬
tion of the capacioufnefs of any portion of fpace, thick-
nefs, as wrell as length and breadth, is taken into con-
fideration. This is called a folid fpace. By this, how¬
ever, is meant only the fufceptibility of meafure in
three ways, or extenfion of three dimenfions. The ad¬
jacent parts or portions of fpace are diftinguifhed from
each other by their mutual boundaries. Contiguous
portions of a line are feparated by points ; contiguous
portions of a furface are feparated by lines \ and conti¬
guous portions of a folid are feparated by furfaces. The
boundaries of any portions of fpace are not to be con-
iidered as parts of the contiguous portions. They muft
be conceived as coirnnon to both ) as the places where
one portion ends and another begins. Space cannot Introduc*
be faid to have any bounds or limits j it is therefore ,
faid to be infinite or unbounded. v
4. Any portion of fpace may be confidered in rela-Relative
tion to its place or fituation among other portions ofan<^ abli)-r
fpace. This portion of fpace wdiich is occupied bylutelPace»
any body has been called the relative place of that bo¬
dy. But this portion of fpace may be confidered as a
determinate portion of infinite fpace 5 and this portion
of infinite fpace occupied by any body has been called
the abfolute place of that body. Space, it is obvious,
taken in this meaning, is immoveable \ for it cannot
be conceived that this identical portion of fpace can be
removed from one place to another. The body which
occupies that fpace may be removed, but the fpace re¬
mains. We have no perception of the abfolute fpace
of any objeft. This may be illuftrated by the motion
of the earth or that of a ftiip. A perfon in the cabin
of a ftiip does not confider the table as changing its
place while it remains fixed to the fame fpot on the
deck. While a mountain is obferved to retain the
fame fituation among other objefls, few perfons think
that it changes its place.
5. The idea of time is acquired by means of the Idea of
power of memory in obferving the fucceflion of events.tlrae*
We conceive time as unbounded, continuous, homoge¬
neous, unchangeable in the order of its parts, and in¬
finitely divifible. It is conceived as a proper quantity
made up of its owm parts, and meafured by them. But
as the relation of the parts of time is unknown, the
only means which wrc can employ to difcover this rela¬
tion, is to find out fome other relation which is more
obvious and better known, to which it may be compa¬
red. We ftiall then have difcovered the fimpleft mea-
fare of time, if wc compare in the fimpleft manner pof-
fible the relation of the parts of time with thofe rela¬
tions which are moft familiar. Hence it follow's, that
uniform motion is the fimpleft meafure of time. For,
on the one hand, the relation of the parts of a right
line is that which is moft eafily conceived j and, on
the other hand, there are no relations more fufceptible
of comparifon wdth each other than equal relations.
Now, in uniform motion, the relation of the parts of
time is equal to that of the correfponding parts of the
line defcribed. Uniform motion then gives us at once,
both the means of comparing the relation of the parts
of time with that which is moft obvious to our fenfes,
and alfo of making this comparifon in the fimpleft
manner. In uniform motion, then, we find the fim-
pleft meafure of time. It may be added, that the mea¬
fure of time by uniform motion, is, independent of its
fimplicity, that which is the moft natural to think of
employing. Indeed as there is no relation with which
w e are acquainted more accurate than that of the parts
of fpace ; and, as in general, a motion, the law of
which is given, would lead us to difcover the relation
of the parts of time, by the known analogy wuth that
of the parts of fpace pafled over, it is evident that fuch
a motion would be the moft accurate meafure of time,
and
*
DYNAMICS.
Motion, rind that which ought to be employed in preference to
’"•'"'v 1 every other. In the actual meafurement of time, fome
event which is imagined always to require an equal
time for its accomplKhment is lelefted ) and this time
is employed as a unit of time or duration, in the fame
way as a foot rule is employed as a mealure of extenfion.
During any obferved operation, as often as this event
is accompliihed, fo often is it fuppofed that the time of
the operation contains this unit. While a heavy body
falls 16 feet, a pendulum, 39^ inches long, makes one
vibration •, but it makes three vibrations, while the
fame body falls 144 feet. It is therefore faid that the
time of a body falling 144 feet, is thrice as great as
the time of falling 16 feet.
4^3
6. Between the affections of time and fpace, there i Motion. ^
is an obvious analogy; and hence in moft languages
the fame words are employed to exprefs the affections hetwe(.,'j
of both. Thus it is that time may be reprefented by the affec-
lines and meafured by motion ; fince uniform motion is tions of
the limpleft fucceffion of events that can be conceived. 'UIie and
In the order of fituation, all things are placed in fpace. lpace‘
In the order of fucceffion all events happen in time.
Having made thefe preliminary obfervations, we pro-
pofe to divide the following treatife into two parts. In
the firft, we (hall confider motion in general. In the
fecond, we (hall treat of moving forces, or of dyna¬
mics.
PART I. O F M O T I O N.
BEFORE we enter on the confideration of the dif¬
ferent kinds of motion, it may be neceffary to notice
fome general circumllances regarding it.
No motion 7. It is impoflible to conceive that any motion can
inftanta- fog inftantaneous. A moving body, in paffmg from
the beginning to the end of its path, mull pafs through
all the intermediate points. Now to fuppofe the mo¬
tion along even the moll minute portions of the fpace
paffed through inllantaneous, is to fuppofe that the mo¬
ving body is in every intervening point at the fame in-
flant *, which is impoilible.
Abfolute 8. Relative motion is the change of lituation with
and relative regar(I to other objects. Abfolute motion is the change
motion. 0£ abfojjjte place. Thefe two motions, it may be ob¬
ferved, may not only be different, but even contrary to
each other. From the relative motions of things which
are the differences of their abfolute motions, we can¬
not find out what are the abfolute motions. It is of¬
ten a fubjeCl of elaborate and intricate invelligation to
difeover and determine the ablblute motions, by means
of obferving the relative motions.
Quantity of 9. The affeftions or circumltances of motion are va-
rbotion. rious with regard to its quantity and its direction. That
affection of motion by which the quantity is determin¬
ed, is called velocity. The length of the line, which
is uniformly deferibed or palled over during fome given
portion or unit of time, is the proper meafure of this
velocity. When a Ihip fails fix miles per hour, fhe de-
feribes a length of line equal to fix miles in the fpace of
a given portion or unit of time, namely, the hour; and
thus the velocity of the Ihip is faid to be afeertained.
Jl ire (hi on 10. Another affection or circumftance of motion is
of motion, its direBion. This is the pofition of the ftraight line
along which the motion is performed. The ftraight
line which a body deferibes or tends to deferibe is call¬
ed its direction. The motion is faid to be in the direc¬
tion AB fig. 1. when the body moved paffes along
the line AB from A to B. In common language, it
is not unufual to exprefs the diredlion of motion in a
manner quite the reverfe of this. We have an in-
itance of this kind in fpeaking of the direction of the
winds. A current of air or wind which moves eaft-
ward is faid to be a wefterly wind, deriving its name
from the point or quarter from which it proceeds, not
as in other cafes, and in ftridl expreflion, from the
point to which it is dire&ed.
11. Motions are of different kinds. They are either Redlllineafr
rectilineal, dedeCted, or curvilineal. In a redtilinealmotlon-
motion the direction remains unchanged during the
whole time that the motion is continued, as when a
body moves from A to B fig. I. In a dedeCled mo- DefledtetV-
tion it is performed along two contiguous ftraight lines
in fucceftion. Thus if a body moves from A to B
fig. 2. and at the point B its direction is changed from
that of AD to BC j this change has been called dc-
fleBion, the quantity of which may be meafured either
by the angle DEC, or by a line DC drawn from the
point D to which the body would have arrived in the
fame time, if its motion had remained unchanged, in
which it has aftually reached the point C. When a
body in moving along deferibes the fides of a polygon,
the defleCtions are repeated, with the intervention of
imdeflefted motions. In curvilineal motion the devia- Curvilinear
tion and defleCtion are fuppofed to be continual. Con¬
tinual defleCtion therefore conftitutes curvilineal mo¬
tion. Let the motion be performed along a curve line
ABCDE (fig. 3.), the direction is continually chan¬
ging. When the body is in the point C the direction
is that of the tangent CF 5 becaufe this direction alone
lies between any pair of polygonal directions, fuch as
CE and Ctf, or CB and CD, however near the points
A and E, or B and D, are taken to the point C.
1 2. Motions have been divided into uniform motions, Divifion of
variable, compound, and curvilineal. Thefe we ftiall motions,
confider feparately in the following feCtions.
Sect. I. Of Uniform Motion.
13. It is of great importance in mechanical difquifi-Importance
tions, to have the characters of uniform or unchanged °^a1J.^ers
motion fixed. For in our conceptions of motion in „niform ,
general, in which we do not turn the attention to its motion,
alterations, the motion is fuppofed to be equable and
reCtilineal. By the deviations from fuch motion only
can we determine the marks and meafures of all
changes •, and hence alfo we are to obtain the meafures
of all changing caufes, or in other words of the me¬
chanical powers of nature.
Proposition I.
14. In uniform motions, the velocities are in the pro¬
portions of the fpQces deferibed in the fame or in equal
times i .
4^4 D Y N A
Uniterm times; or as it is fometfmes expreffed, The velocities are
i . onon. proportional to the /paces defenhed in equal times.
The fpaces deferibed are the mealures of the velo¬
cities, and things are proportional to their meafurds.
Let the fpaces deferibed in the time T, be reprefented
by S and j, and let the velocities be reprefented by
Vr and v. We have the analogy V : n — S : r. Or,
as it may be expreffed by the proportional equation
v == s.
Prop. II.
In uniform motions with equal velocities, the times
are in the proportion of the fpaces deferibed during their
currency. Or, as it is alfo exprefled, The times are
proportional to the fpaces deferibed with equal velocities.
For in uniform motions, equal fpaces are deferibed
in equal times. The fucceflive portions of time there¬
fore are equal, in which equal fpaces are deferibed in
fucceflion } and the fums of the equal times mull be
proportional to the correfponding fums of equal fpaces.
In all cafes, therefore, which are fufceptible of being
.reprefented by numbers, this propofition is evident.
And it may be extended to all other cafes, in a way
fimilar to that in which Euclid has demonftrated that
triangles of equal bafes are in the proportion of their
bafes.
16. As proportion can only take place between
.quantities of the fame kind, all that is to be under-
ftood by the expreflions in the above propohtions, wdhch
are far from being accurate, is, that the proportions of
the velocities and the times are the fame with the pro¬
portions of the fpaces. For as fpace and time are
quantities of a different nature, it is evident that we
cannot divide fpace by time. Thus when it is faid that
the velocities are as the fpaces divided by the times, it
is an abridged mode of expreffion, which fignifies that
the velocities are as the relations of the fpaces to the
fame common meafure, divided by the relations of
the times to the fame meafure. Thus, for example, if
we take a foot for the meafure of the fpaces, and a
minute for the meafure of the times, the velocities of
two bodies which move uniformly, are to each other
as the number of feet deferibed, divided by the num¬
ber of minutes which the bodies require to deferibe the
portion of fpace palled through, and not as the feet di¬
vided by the minutes.
Uniform 17. Hence it is that uniform motion is univerfally
•motion a employed as a meafure of time. But it is often diffi-
Qj tjme cult to find out wdiether the motion which is propofed
for the meafure of time be perfeftly uniform. What
then are the means to afeertain this ? To this it may
be anfwered that there is no motion which is not uni¬
form, the law of which we can determine exactly } fo
that this difficulty only proves that we cannot afeertain
the relation of the parts of time with mathematical
precifion j but it does not follow that uniform motion
from its nature may not be the firft and limpleft mea¬
fure. And having no flriiElly accurate meafure of
time, wre endeavour to difeover the meafure which
comes neareft in the motions which approach neareft to
Method of uniformity. ,
afee .a1 jg. There are three wrays by wffiich it may be afeer-
nio uj-161- 3 ta^ned that a motion is nearly uniform. 1. When the
neariy um- moving body deferibes equal fpaces in times which we
f jrm. judge to be equal 5 and wre can determine that the
1
/
• M I C S.
Part I.
times are equal, after having obferved from repeated Uniform
experience that fimilar events take place in the fame , Motion.-
times. Thus we conclude that the times wffiich the
fame clepfydra requires to be emptied are equal 5 fo alfo
the times in which the fame quantity of fand runs in the
fandglals j the times in which the ffiadow moves over
the lame fpac.e on the fundial •, the times of the fame
number of vibrations of a pendulum of the lame
length ; and the times of the revolution of the heaven¬
ly bodies through the fame fpaces are equal. If then
it is found by obfervation that a body during the fame
times palfes over equal fpaces, we conclude that the
motion is uniform. 2. Another method of afeertaining
how far any motion is uniform, is when the effect of the
accelerating or retarding caufe, if fuch operate, is imper¬
ceptible. It is by combining thefe two methods that
we conclude the motion of the earth round its axis to be
uniform ; and this inference is not only not oppofed by
any of the celellial phenomena, but feems to be in per-
fe£t accord with them. 3. By a third method of deter¬
mining the uniformity of any motion, we compare it
with others \ and when the fame law is obferved in
both the one and the other, wre may conclude that the
motion compared is uniform. Thus if feveral bodies
move at fuch a rate that the fpaces deferibed in the
fame time are always to each other, either precifely or
very nearly fo, in the fame ratio, the motion of thefe
bodies, w^e conclude, is either precifely, or at leal! very
nearly uniform. For if a body A wffiich moves uni¬
formly pafles through the fpace E during the time T
taken at pleafure, and another body B alfo moving uni¬
formly, pafles through the fpace e\ during the fame
time T, the relation of the fpaces E, e will be ahvays
the fame, whether the two bodies have begun to move
in the fame or in different inftants 5 and it is only to
uniform motion that this property belongs. Where¬
fore if we divide the time into parts, wffiether equal or
unequal, and if it be obferved that the fpaces pafled
through by twTo bodies during one part of the time,
are always in the fame relation, the greater the num¬
ber the parts of the time taken, the more there is rea-
fon to conclude that the motion of each body is uni¬
form. None of thefe methods, it has been obferved,
pofiefles geometrical precifion ; but they are fufficient,
efpecially wffien they are repeated and taken together,
to afford a fatisfactory conclufion, if not with regard
to abfolute uniformity of motion, at leaf! with regard
to a near approximation to uniform motion.
Prop. III.
19. In uniform motions, the fpaces deferibed are in the
compound ratio of the velocities and the ratio of the times.
This propofition is frequently expreffed otherwife thus;
The fpaces deferibed with an uniform motion are propor¬
tional to the producls of the times and the velocities : Or
otherwife thus 5 The fpaces deferibed with a uniform
motion are proportional to the r ell angles of the times
and the velocities.
For let S be the fpace deferibed with the velocity V,
in the time T, and let s be the fpace deferibed with
the velocity v, in the time t. Let another fpace Z be
deferibed in the time T with the velocity v.
Then by propofition 1 ft wTe have S : Z = V : ry,
And by propofition 2d Z : r T :
By
Sea. ii. * d Y_ N , A
Variable By cotnpontion of ratios therefore (or by VI. 23. Eu-
t Motions, we ^ave =:V x T : X x Zr: r X Z. > that is,
: j.
The above are all equivalent expreflions which are
demonftrated by the fame compofition of ratios. The
produfts or re£langles of the tunes and velocities, are
the produfts of numbers which are ns the times, mul¬
tiplied by numbers which are as the velocities *, or the
reel angles whofe bafes are as the times, and whofe
heights are as the velocities.
Corollary.
20. If the /paces deferibed in two uniform motions be
equal, the velocities are in the reciprocal proportion of
the times.
For in this cafe the produfts VT and d t are equal,
and therefore V : V—t: T, or V : vr^:-^ : -• Or, be-
caufe the re&angles AC, DF (fig. 4.) are in this cafe
equal, we have (by VI. 14. Euclid) AB : BFzrBD :
BC, that is V : vz=.t: T.
Prop. IV. *
21. In uniform motions, the times are as the /paces,
-dire&ly, and as the velocities, inverfely.
For by Prop. III. S : x ~ VT :vt\
Therefore, Svt — s'VT,
And, T:/=Sv:xV.
Or,
And,
S x
T : t =r— :
V v
. x
* V
Prop. V.
22. In uniform itpotions, the velocities are as the
/paces, direBly, and as the times, inverfely.
$iV t — s VT,
V;v=:Sr:xT.
For by Prop. IV.
Therefore
Or,
And
V:s> = ™:-
. x
V —
■ t
23. The values of the refults of thefe propofitions
are not changed by the abfolute magnitudes of the
fpace and time, if both are changed in the fame ratio.
The value of 1 2-^, or of is the fame with
24,, I o
half a foot per fecond. Therefore, if s' be the ex-
preffion of an extremely minute portion of fpace de¬
feribed with this velocity in the fmall portion of time
t', the velocity v is Hill accurately expreffed by -
s*
And the accurate expreflion of the time t' is —.
Sect. II. Of Variable Motions.
Motions ob- 24. Ix obferving the phenomena of nature, it rarely
•ferved in happens that the motions to which our attention is di-
na,^re . reeled are perfe&ly uniform. Thefe motions, however,
foJLyUIU" Vol. vn. Part II,
M I C S. r 4<>5
we diftinaiy conceive, with all their properties j and
it is obvioufly of the utmoft importance that all the ■ . — >
deviations from uniform motions be cleariy undeihood j
becaufe thefe deviations afford the only marks and
meafures of the variations, and therefore of the caufes
which produce thefe changes.
25. When a body continues to move uniformly in
the fame direction, its motion, or circumflances with
refpedt to motion, have fuffered no change, ihe con¬
dition of that body, therefore, muft be allowed to be
the fame in any two portions of its path, whatever the
dirtance of thefe portions may be. And becaule a^
change of place is involved m the very conception of
motion, the difference of place does not. imply any
change. Two bodies, therefore, moving with the fame
velocity in this path, or in tivo lines parallel to it, their
condition in refpeiff of motion muft be allowed to be
the fame. Their direftion is the fame, and their rate
of motion is the fame. The velocity, therefore, and Veloci-tj
the direction of a body, are the only circumftances ^jyC*
which feem to enter into our conception of the ftate of con .eivtfl
a body, in refpeft of motion. Changes either in the m motion,
velocity, or in the direction, or in both of thefe circum¬
ftances, include all the changes of which this condi¬
tion is fufceptible. Let us now confider the firit of
thefe changes, namely, changes of velocity.
Of Accelerated and Retarded Motions.
26. It has been afeertained by experiment and ob~
fervation, that a itone in falling is carried downward
with greater rapidity in every fucceftive period of its
fall. During the firli fecond it falls 16 feet •, during
the next it falls 48 feet ; during the third, it falls 80
feet; during"\he fourth it falls 11 2 feet ; continuing
to fall, during every fucceflive fecond 32 feet , more
than during the preceding fecond. A body moving in
this manner is faid to have an accelerated motion. But
if a body be projected perpendicularly upwards, the
very reverfe takes place in the circumdances of its mo¬
tion. It is obferved to rife with a motion which is
continually retarded. Thefe bodies therefore are con¬
ceived to be in every fucceeding inltant in different
ftates of motion. The velocity of the falling body is
conceived to be greater in a certain in:1 ant than in any
preceding inftant 5 as, for example, when it has fallen
144 feet its velocity is faid to be thrice as great as
when it has fallen only 16 feet. But this inference it
is evident cannot be made diredly by comparing the
fpaces deferibed in the following moments j for in thefe
it falls 11 2 and 48 feet j or by comparing the fpaces
immediately preceding j for in thefe the body fell 80
and 16 feet. But in this expreftion it is fuppofed that
the variable condition of a body, called its velocity, is,
in every inilant fufceptible of an accurate meafure 5 and
yet in no moment, however fhort, does the body de-
feribe uniformly a fpace -which can be taken as the
meafure of its velocity at the beginning of that mo¬
ment ; becaufe the fpace deferibed in any moment is
too great for meafuring the velocity at the beginning
of the moment, and too {mail for the meafure of its ve¬
locity at the end of it. Till however fuch a meafure
is obtained, the mechanical condition of the body is not
known.
27. But in a continually accelerated motion, no
fuch meafure can be obtained. No fpace is deferib-
3 N ed
66 D Y N A
Variable ed in an inflant : for this requires time. In that in-
Motlons' , ft ant, however, the body pofleffes what has been called
a potential velocity, that is, a certain tendency or de¬
termination, which remaining unchanged, caufes it to
defcribe a certain fpace uniformly during fome aftign-
able portion of time. At another inftant it has another
determination, by which, if it be not changed, another
Ipace would be uniformly defcribed in an equal portion
of time. Now it is in the difference of thofe two de¬
terminations that its difference of mechanical condition
confifts. The marks and meafures of thefe determina¬
tions are known from the fpaces which would be uni¬
formly defcribed. Thefe therefore muft be carefully
inve (ligated as the meafures of the velocities ; and the
proportions of thefe fpaces are to- be taken as the pro¬
portions of the velocities.
Prop. VI.
28. Let the Jlraiglit line ABD (fig. 5.) be clcfcribcd
with a motion continuallij varied, it is required to deter¬
mine the proportion of the velocity in the point A, to the
velocity in any other point C.
Let the right line a b d, reprefent the time of this
motion along the path AD, fo that the points a, b, c, d,
may denote the inftants of the moving body being in
A, B, C, D, and the portions a b, be, c d, may ex-
prefs the times of deferibing AB, BC, CD, that is,
may be in the proportion of thofe times •, and let a e,
perpendicular to a d, exprefs the velocity of the moving
body at the inftant a, or in the point A. Let e g hbt
a line, fo related to the axis a d, that the areas abfe,
^csfi c dhg, comprehended between the ordinates
a e, bf, eg, dh, all perpendicular to ad, may be
proportional to the fpaces AB, BC, CD, defcribed in
the times a b,b c, c d, and let this relation hold in eve¬
ry part of the figure. Then the velocity in A is to
the velocity in B, or C, or D, as a e to bf, or eg, or
d h. Or it may be expreffed in other words, If the ab-
fcijfa 2.6., of a curve e g h, be proportional to the time of
any motion, and the areas interrupted by parallel ordi¬
nates be proportional to the fpaces defcribed, the velocities
ere proportional to thofe ordinates.
Make b c and c d equal, fo as to reprefent very fmall
and equal moments of time, and make p a equal to
one of them. Complete the redfangle p a e q. This
will reprefent the fpace uniformly defcribed in the mo¬
ment pa, with the velocity ae (Propof. 3.) Let PA
be that portion of fpace thus uniformly defcribed in the
moment p a. Let the lines i m, k n, parallel to a d,
make the reftangles b c mi, and c d n h, refpeftively
equal to the areas b cgf and c dhg. If the motions
along the fpaces PA and BC had been uniform, the
velocities would have been proportional to the fpaces
defcribed (Propof. 1.) becaufe the ^times pa, and £ c
are equal. That is, the velocity in A would be to
the velocity in C, as the re&angle p a e q Xo the area
b c gf, that is, 21s paeq to bem i, that is, as the bafe
a e to the bafe c m, becaufe the altitudes p a and b c
are equal.
But the motion along the line BC is not reprefented
as uniform ; for the line f g h diverges from the axis
b d, the ordinate eg being greater than bf And
therefore the fpaces meafured by thefe areas increafe
fafter than the times j and thus the figure reprefents an
accelerated motion. Therefore the velocity with which
M I C S. Part I.
BC would be Uniformly defcribed during the moment Varidb'e
b c, is lefs than the velocity at the end of that moment, j Motions,
that is, at the inftant c, or in the point C of the path ; * ‘
and therefore it muft be reprefented and meafured by a
line greater than c m.
In the fame manner it is proved that c k reprefents
and meafures the velocity with which CD would be
uniformly defcribed during the moment c d. And
therefore, fince the motion along CD is alfo accelerat¬
ed, the velocity at the beginning of that moment is lefs
than the velocity with which it would be uniformly de¬
fcribed in the fame time, and muft be reprefented by a
line lefs than c k.
Therefore the velocity in A, is to that in C, in a
lefs ratio than that of a e to c m, but in a greater ratio
than that of a e to c k. But in this cafe, as long as
the inftant b is prior, and dpofterior, to the inftant c, cm
is lefs, and c k is greater, than eg. Therefore the velo¬
city in A is to that in C in a ratio that is greater
than any ratio lefs than that oi a e to c g. And, con-
fequently the velocity in A is to that in C, as c <*
to eg.
It may be proved in the fame way, with refpeft to
the velocity in any other point Dand therefore the
propofition may be confidered as demonftrated. And
had the motion along BCD, inftead of being accelera^-
ted as in this cafe, been retarded, the fame reafoning
would ftill apply.
Corollaries.
29. Cor. I. The velocities in different points of the
path AD, are in the ultimate ratio of the fpaces defcrib¬
ed in equalfmall moments of time. Dfaw g 0 parallel
to a d. Then the velocity in the inftant a, is to that
in the inftant c, as a e to eg, that is, as the reftangle
p e to the redlangle c 0, that is, as p a e q to c d h g,
nearly. As the moments are diminilhed, the differ¬
ence g 0 h between the reflangles cg 0 d and eg h d, di-
miniffies nearly in the duplicate ratio of the moment.
If then the moment be taken 4, or ^ of c d, the
error go h is diminilhed to , or ^ : the corollary
is now manifeft 5 for the ultimate ratio of eg 0 d to
eg h d is the ratio of equality. That is, the velocity in
A is to that in C, in the ultimate ratio of PA to BC
defcribed in equal fmall moments.
There are many cafes in which the fpaces deferibed
in very fmall moments can be meafured, and yet the
ultimate ratio cannot be afeertained. Thefe fpaces
muft then be taken as meafures of the velocity. And
by taking half the fum of the fpaces BC and CD, for
the meafure of the velocity in the point C, the error
is almoft reduced to nothing.
30. Cor. 2. The momentary increments of the fpaces
defcribed, are in the compound ratio of the velocities, and
the ultimate ratio of the moments.
For the increments PA, CD are as the redlangles
p e and c 0 ultimately, (Propof. 3.) ; and thefe are in
the compound ratio of the bafe a e, to the bafe d 0, and
the ultimate ratio of the altitude p a, to the altitude
c d. This may be expreffed by the proportional equa¬
tion S ZZ.V t.
• s • s
31. Confequently vzz'-r, and f— The equation
. ' t • v
\
$e£t. IX.
Variable
D Y N A
Motions! s’^ vi , and ^ f Teem to be the fame with
 J ‘ / * ^
thofe in (23), but there the fmall fpace s' was defcnb-
ed uniformly, and the equations were abfolute. In
30 and 35, s does not reprfefent a fpace uniformly de-
fcribed. But S : s expreffes the ultimate ratio of S' to /
■when they are dimmiflied continually, and vanilh to¬
gether. Therefore the meaning of the equation
s^= vt is, that the ultimate ratio of S' to s\ is the fame
with that of VT' to vt'.
3 2. The following is the converfe of this propofi-
tion.
If the ahfciffa ado/" the line e f h, reprefent the time
of a motion along the line ABD, and if the ordinates
ae, bf, eg, &c. be as the velocities in the points K,
B, C, &c. then the areas are as the fpaces defenbed.
This is proved by an indiredl demonftration, thus :
For if the fpaces AB, AD, be not proportional to
the areas a bf e, a d h e, they mull be proportional to
fome other, a bf' e, a d h' e, of another line ef h\ paf-
fmg through e. Afluming this to be true, then (by
Propof. 6.) the velocity in A is to that in B, as e to
bf. Therefore a e : bf—a e : bf which is abfurd.
33. The relation between the fpace deferibed and the
time which elapfes is the only immediate obfervation to
be made on thefe variable motions. By means of the
foregoing propolitions, the mechanical condition of the
body, or rather the effefl and meafure of this condi¬
tion, denominated velocity^ is inferred. I he fame in¬
ference is made in another way. Sir Ifaac Newton
often reprefents the uniform lapfe of time by the uni¬
form increafe of an area during the motion along the
line taken for the abfeiffa. The velocities or determi¬
nations to motion in the different points of this line,
are inverfely proportional to the ordinates of the curve
which bounds this area.
Along the ftraight line AD, (fig. 6.) let a point
move with a motion any how continually changed, and
let the curve line LIH be fo related to AD, that
the area LICB is to the area LHDB as the time
of moving along BC to that of moving along BD.
Let this be true in every point of the line AD. Let
C c, D d, be two very fmall fpaces deferibed in equal
times, draw the ordinates 1 c, h d, and draw 1 h, hi
perpendicular to IC, HD.
The areas IC c z, and HD d h mull be equal, be-
caufe they reprefent equal moments of time. It is evi¬
dent alfo, that as the fpaces C c and D d are continually
diminifhed, the ratio of IC c 1 and HD d h to the rect¬
angles k C c i and I'D d k continually approximates to
that of equality, and that the ratio of equality is the
limiting or ultimate ratio. Since therefore, the areas
IC c i and DID dh are equal, the reftangles kCci
and ID dh are ultimately in the ratio of equality.
Therefore their bafes i c and h d are inverfely as their
altitudes Cc and D d, that is, ic\ h d—D d: C c.
But as C c and D d are deferibed in equal times, they
are ultimately as the velocities in c and d (29). Ihere-
fore i c and h </, are inverlely as the velocities in c and
d. And as the fame reafoning may be applied to every
point of the abfeiffa, the propofition is demonftrated.
34. In all cafes, then, in which the relation be¬
tween the fpaces deferibed, and the times elapfed can
be difeovered by obfervation, we difeover the tnechani-
M I C S. _ 467
cal condition of the moving body, or its Velocity. But
in the praCHcal application of thefe conclufions, recourfe ,1 0 ^ons• ,
mull always be had to arithmetical conclufions •, and
the indications of thefe are the algebraic fymbols of
geometrical reafonings. Thus any ordinate c g, (fig.
5.) is reprefented by v, and the portion c d o£ the ab¬
feiffa by /, and the area cdhg, or its equal, the red-
angle c dog, by Vt. This re&angle then being as the
correfponding portion CD of the line of motion, and
CD being reprefented by s, we have the equation
s=vt.
33. The mathematical confequences of thefe repre-
fentations may now be affumed to be true j and there¬
fore as in (23.) Algebraic fymbols being the
V
reprefentations of arithmetical operations, they repre¬
fent more remotely the operations of geometry, and only
becaufe the area of a redangle is analogous to the pro-
dud of numbers wdiich are proportional to its fides.
The fymbolJv t being ufed to reprefent the fum of all
thefe redangles, expreffes the wdiole area a d h e, as
well as the whole line of motion AD j and the equa¬
tion may be Hated 4= A- In like manner J s wall
be equivalent to J t, that is, to t, and will exprefs the
whole time a d. It is plain too that s reprefents the
v
ordinate DH of the line LKIH (fig. 6.) becaufe any
portion D d ot its abfeiffa, is properly reprefented by
r, and the ordinates are reciprocally proportional to
the velocities, that is, are proportional to the quotients
of fome conftant number divided by the velocities, and
therefore to -. And as t is reprefented by the red-
v
angle k C c i, which is alfo reprefented by s X~, we
have/’—-, and /— /-, as above.
-» ^ v
36. In one cafe of varied motion, when the line efg h
(fig. 5.) is a ftraight line, the charaders are very par¬
ticular and ufeful. Let this cafe of motion be repre¬
fented along the line AD (fig. 7.) andJet/w, be, cd,
reprefent equal moments of time, in which the moving
body deferibes PA, BC, CD ; and draw////, gn,e s,
parallel to the abfeiffa a d. Now it is evident that
/// g, and n h are equal, or that equal increments of ve¬
locity are acquired in equal times j e y, e r, e s, are al¬
fo proportional to qfrg,s h, and therefore the incre¬
ments qf rg, r h, of velocity are proportional to the
times a b, a c, ad, in which they are acquired. This
motion may very properly be denominated uniformly
accelerated; for here the velocity increafes in the fame
ratio with the times, and equal increments are acquired
in equal times. If the line e h cut the abfeiffa in v, it
will reprefent a motion uniformly accelerated from reft,
during the time v d, and thus exhibit the relations
between the fpaces, velocities, and times in fuch mo¬
tions.
Hence it follows from this mode of expreffing thefe
3 N 2 relations,
v
468 D Y N A
Variable relations that in motions uniformly accelerated from a /late
?»Iotion^. ^ of ref, the acquired velocities are proportional to the times
from the beginning of the motion. For a e,bf eg, dh, re-
prefent the velocities gained during the times v
v b, v cf v d} and are in the fame proportion with thofe
lines.
37*—Alfo, the momentary increments of velocityy
are as the moments in which they are acquired.
2. Alfo, the /paces defenbed from the beginning of the
motion, are as the fquares of the times.
3. Alfo, the increments of the fpaces are as the incre¬
ments of the fquares of the times ; reckoning from the
beginning of the motion.
4. Alfo, the fpaces defenbed from the beginning of
the motiony are as the fquares of the acquired velo¬
cities.
5. Alfo, the momentary increments of the fpaces are
as the momentary increments of the fquares of the velo¬
cities.
6. Alio, the fpace deferibed during any portion of time
by a motion uniformly accelerated from re fly is one-half
of the fpace uniformly deferibed in the fame time with
the fnal velocity of the accelerated motion.
7. And the fpace deferibed during any portion of the
time of the accelerated motiony is equal to that which
would be deferibed in the fame time with the mean be¬
tween the velocities at the beginning and end of this por¬
tion of time.
In the inveftigation of all other varied motions, the
properties of uniformly accelerated motion dated above,
will be found extremely ufeful, and efpecially in cafes
where approximation only can be eafily obtained. Eut
for the fuller illuflration of thefe properties the reader
is referred to Robifon’s Elements of Mechanical Philo-
fophy, p. 38.
38. Suppofmg the acceleration to be always the
fame, we conceive of this conftancy, that in equal
times there are equal increments of velocity 5 and there-
lore that the augmentations of velocity are proportion¬
al to the times in which they are acquired. That ac¬
celeration then, according to this fuppoiition, muft be
accounted double, or triple, &c. where the velocity
acquired is double or triple.. And, acceleration being
confidered as a meafurable quantity, the augmentation
of velocity uniformly acquired in any given time is its
meafure.
Corollary.
39. Therefore, accelerations are proportional to the
fpaces deferibed in equal timesy with motions uniformly
accelerated from a fate of ref. For in this cafe the
fpaces are the halves of what would be uniformly de¬
feribed in the fame time with the acquired final veloci¬
ties, and are therefore proportional to thefe velocities,
or to the accelerations, fince the velocities were acqui¬
red in equal times.
40. It is then laid, that accelerations are proportion¬
al to the increments of velocity uniformly acquired, di-
reBhjy and to the times in which they are acquired in-
verfely.
v
t’
This relation between acceleration, velocity, and time,
is alfo true, in uniformly accelerated motion, with re-
fpe£t to all momentary changes of velocity, as well as
M I C S.
Part I.
to thofe cafes of motion palling through all degrees of Variable
velocity from nothing to the final magnitude v. For , Motions,
the velocity increafing at the fame rate with the time,' ' v
we have v : v'~t: t'; and v' and t' exprefs the fimulta-
neous increments of velocity and time.
41. But if the augmentation of velocity be the mea¬
fure of the acceleration, and therefore proportional to
it, and if in uniformly accelerated motions, the veloci¬
ty increafes at the fame rate with the times, the incre¬
ments of velocity are as the accelerations and as the
times jointly. Hence the proportional equation
vdzaty
and v'— a t'.
42. .It appears from (39.), that when the velocity
has uniformly increafed from nothing, the fpaces de¬
feribed in equal times are proper meafures of accelera¬
tion. And in (37.—3.) uniformly accelerated mo¬
tions, the fpaces are as the fquares of the times. There¬
fore, •when the acceleration continues the fame, the
fradlion — muft alfo remain of the fame value, and a
• • s
is proportional to —. And therefore, accelerations
are proportional to the fpaces deferibed with a motion
uniformly accelerated from ref, direBlyy and to the
fquares of the times inverfely.
43. And fince a
therefore a ~ —.
• j-
. v , . v v ,
— -, we have a — : but ■y/rr a
' t ■ vt ’ ■ *
Therefore we have another mea*.
fure of acceleration, viz. Accelerations are dire&ly
as the fquares of the velocities, and inverfely as the
fpaces along which the velocities are uniformly aug¬
mented.
44. Eut when the fpaces are equal, we have a ==■ v*,
and in uniformly accelerated motions, that is, when a
remains conftant, the fpace being increafed in any pro¬
portion, v* increafes in the fame proportion ; it follows
that vz increafes in the proportion both of the accele¬
ration and of the fpace. And therefore, in general,
we have, v* = as. And, as in 41, 42, we (hall have
v* zip a S, and V2— vz±p. a S — a r, or ~ S — s, which
may be thus expreffed v v'zza s', that is, in a motion
uniformly accelerated, the momentary change of the
fquare of the velocity is proportional to the accelera¬
tion and to the fpace jointly. Thus it appears, that
the acceleration continued during a given time t, cr
produces a certain augmentation of the iimple veloci-f
ty; but the acceleration continued along a given fpace
r, or S', produces a certain augmentation of the fquare
of the velocity.
45. But accelerations which are conftant and uni¬
form, and ftich as have been confidered, are very rare
in the phenomena of nature. They are as variable as
velocities, and therefore it is not lefs difficult to difea-
ver their aftual meafure. By changes of velocity only
we obtain any knowledge of the changing caufe. From
the continual acceleration of a falling body we learn,
that the fame power which makes it prefs on the hand,
preffes it downward, as it falls through the air, and
whatever be the rapidity of its defeent, it is from ob-
ferving that it acquires equal increments of velocity in
equal times, that we know the downward preflure to
be the fame.
In
Sea. II. D Y N A
Variable In the feme way that we obtain meafures of a velo-
Motions clty which is continually varying, wfi may obtain ac-
' * ' curate meafures of a fimilarly varying acceleration. A
line may be conceived to increafe along with the velo¬
city, and at the fame rate *, and this rate of increafe of
velocity is what is called acceleration, in the fame way
as the rate at which the line increafes, is what is called
velocity. If, then, we conlider the areas (fig. 5.) or
the line AD, as reprefenting n velocity •, the ordinates
to the line eg //, which were demonltrated to be pro¬
portional to the rate of variation of the area, will be
proportional to the variation of the velocity, that is, to
the acceleration.
Prop. VII.
46. If the ahfcijfa a d of a curve line e g h reprefent
the time of a motion, and if the areas a b f e, a c g e,
adhe, &c. are proportioned to the velocities at the in¬
fants b, c, d, &c. then the ordinates * ft, b f, eg, d h,
&c. are proportional to the accelerations at the infants
a, b, c, d, &c.
By fubftituting the word acceleration for the word
velocity, the fame demonilration may be applied here
as in Prop. 6. (28.) From this propofition may be de¬
duced fome corollaries of praclical ufe in mechanical
difeuffions.
47. The momentary increments of velocity are as the
accelerations, and as the moments jointly.
For the increment of velocity in the moment c d vs,
accurately reprefented by the area cdhg, or by the
re£tangle c d n k ; and cd accurately reprefents the mo¬
ment. Alfo, the ultimate ratio of c £ to fuch another
ordinate b i, is the ratio of eg to bf; that is, the ratio
of the acceleration in the inftant c to that in the inftant
b. And therefore the increment of velocity during the
moment />« is to that during the moment cd ks p a ae
toedydg. Or it maybe exprefl'ed by the propor¬
tional equation v = a t.
48. Converfely. The acceleration a is proportional
to as in the cafe when the motion is uniformly ac-
t
celerated (40.)
And as the area of this figure is analogous to the
fum of all the inferibed re&angles, when the circum-
ftances of the cafe admit of its being meafured, it may
be exprelfed by/^ t ; and thus
is obtained the whole
velocity acquired during the time AC, and we fay v ==
The intenfities (or at lead their proportions) of the
accelerating power of nature in the different points of
the path being frequently known, we wifh to difeo-
ver the velocities in thofe points. This may be done
by the following propofition.
Prop. VIII.
49. If the abfeifa AE (fig. 8.) of a line ace be
the [pace along which a body moves with a motion con¬
tinually varied, and if the ordinates A. a, BA, Cc, &c.
be proportional to the accelerations in the points A, B,
C, &c. then the areas AB A AT) da, ATLea, &c.
are proportional to the augmentations of the fquare of the
velocity in A at the points B, D, E, &c.
3VI I C S. 469
Take BC, CD, as two very fmall portions of the Compound
line AE, and draw bf, eg, parallel to AE. Then,,;
fuppofing the acceleration B A, to continue through the
fpace BC, the reftangle BA/C will exprefs/he aug¬
mentation made on the fquare of the velocity in B. In
the fame w^ay C D will exprefs the augmentation of
the fquare of the velocity in Cand, in like manner,
the redangles inferibed in the remainder of the figure
will exprefs the increments of the fquares of the velo¬
city acquired, while the body moves over the corre-
fponding portions of the abfeiffa. And, therefore, the
whole augmentation of the fquare of the velocity in A
(fhould there be any velocity in that point) during the
time of moving from A to B, will conflitute the ag¬
gregate of thefe partial increments. The fame thing
muit be affirmed of the motion from B to E. And,
when the fubdivifion of AE is carried on without end,
it is plain that the ultimate ratio of the area AT. e a to
the aggregate of inferibed redangles, is that of equa¬
lity ; that is, when the acceleration varies continually,
the area AB A a will exprefs the increment made on
the fquare of the initial velocity in A, while the body
moves along AB } and the lame mull be affirmed with
refped to the motion along BE. And, therefore, the
intercepted areas AB A a, BD dA, DE e d, are propor¬
tional to the changes made on the fquares of the velo¬
cities in the points A, B, and D.
Corollaries.
50. Cor. 1. If the body had no velocity in A, the
areas AB A a, AY) da, ike. are proportional to the
fquares of the velocity acquired in the points B, D,
&.c.
Cor. 2. The momentary change on the fquare of the
velocity, is as the acceleration and increment of the
fpace jointly ; or we have v V— a .r.
Cor. 3. v v being equal to halj the increment of the
fquare of the velocity, it follows that the area AE e a,
/* •
as is only equal to —-—, taking v and
V as the velocities in A and E.
51. What has now been faid of the acceleration of
motion, is equally applicable to motions that are re¬
tarded, whether thefe motions be uniform or unequable.-
The momentary variations in this cafe are to be taken
as decrements of velocity inllead of increments. A
moving body, fubjed to uniform retardation till it
come to reft, will continue in motion during a time
proportional to the initial velocity •, and deferibe a
fpace proportional to the fquare of this velocity j
and the fpace which is fo deferibed, is one half
what it would have been if the initial velocity had con¬
tinued undiminilhed.
Sect. III. Of Compound Motions.
52. Having obtained the marks and meafures
every variation of velocity, we are now' to difeover fi-1/1^)1”
milar charaderiftics for every change of diredion. In diredion
the above inveftigation of the general marks of any
change of motion, it is plain that the change being the
fame in any ttvo or more inftances, the ollenffiale marks
muff alfo be the fame, whatever may have been the
previous
47° < D Y N A
Compound previous condition of the moving bodies. In every cafe
, Mo|lons-| of change, fome circumftance in the difference between
the former motions and the new motions muff be ob-
ferved, which is exactly the fame both in refpeft of ve¬
locity and of diredlion. One of the bodies then may
be fuppofed to have been at reff ; and thus the change
produced on it, is the motion which it has acquired, or
the determination to this motion. Therefore, ci change
of motion is itfelf a motion, or determination to motion.
In the above cafe, it is the new motion only; but it is
not the new motion in every other cafe. For fuppo-
fing the previous condition of the body to have been
different from that of a body at reft, and fuppofing the
fame change produced on it, the new condition of the
one body muff be different from the new condition of
the other. The change, therefore, being the fame in
both cafes, the new condition cannot be that change.
But, when the fame change happens in any previous
motion, the difference between the former motion and
the new motion, muff indicate fomething that is equi¬
valent to the motion produced in a body previoufly at
reft, or the fame with that motion, this body having
received the fame change. And the difference be¬
tween the new motions of the two bodies will be fuch
as fhall indicate the difference between the previous
conditions of each body. The change of motion then
is itfelf a motion ; and this being affumed as a princi¬
ple, we are now to endeavour to difcover a motion,
which alone fhall produce that difference from the for¬
mer motion, which, in all cafes, is obferved in the
new motion. This is to be confidered as the proper
charadteriffic of the change.
•iliuftratec!, $3 • ^ ^e following motions may ferve as an illuffration
of thefe conditions. Let it be fuppofed that the ffraight
line AB (fig. 9.) lies eaff and weft, and that it is crof-
fed by the line AC from north to fouth. Suppofe this
line AC to be a rod or wire, and to be carried along
the line AB in one minute, but always in the fame po-
fition, that is, lying north and fouth. The end of the
rod or wire A having moved uniformly one-third of
AB at the end of 23", it will be in the pofition D d 5 j
at the end of 40" it will have the pofition E c t j and
at the end of the minute it will be in the pofition B b.
Let'the line AB, in the mean time, (fuppofing it
alfo to be material) be uniformly moved from north to
fouth, and always parallel to its firft pofition AB.
When it has palled over one-third of AC, at the end
of 20", it will be in the pofition m d n ; at the end of
40" it will have the pofition o e p, and A o is two-
thirds of AC. At the end of the minute, it will have
the pofition C £ s b. It is evident that the common in-
terfeftion of thefe two lines will be always in the dia¬
gonal A b of the parallelogram AC b B ; for the pa¬
rallelogram A m d D is limilar to the parallelogram
AC b B, becaufe AD : AB—A m : AC 5 and, in like
manner, A o e E is a parallelogram fimilar to AC b B.
Therefore, thefe parallelograms are about a common
diagonal Ab.
Again, the motion of the point of interfe&ion of
thefe lines is uniform j for AD : AB—A d : A b, and
AE : AB=r A e : A b, &c. Therefore the fpaces A d,
A e, A b are proportional to the times.
Thus the interfecfion of two lines having each a uni¬
form motion in the diredlion of the other, moves uni¬
formly in the diredlion of the diagonal of the parallelo-
3 .
M I C S. Part T,
gram, which is formed by the lines in their firft or Compound
laft pofition 5 and the velocity of the interfedlion is to , M°tions-
the velocity of each of the motions of the lines as the v '
diagonal is to the fide in the diredlion of which the
motions are made. This motion of the interfedlion is
very properly faid to be compounded of two motions
in the direction of the fides \ for which the point d of
the line D 2 moves eaftward, the fame point d of the
hnemdn is at the fame inftant moving fouth ward.
The point d, therefore, may be confidered as a point
of both lines, partaking in every inftant of both mo¬
tions. The motion along A b then contains both mo¬
tions along AB and AC, and being identical with a
motion compounded of thefe motions, indicates both,
or the determination to both. In every fituation of the
point of interfeftion, its velocity is compounded of the
velocity AB and AC. A body, therefore, whofe mo¬
tion continued unchanged, would have defcribed AB
in one minute j but when it reaches the point A, it
turns afide, and defcribes A b uniformly in the fame
time ; the change then which the body fuftains in the
point A is a motion AC. For luppofe the body had
been at reft in the point A, and it is obferved to de-
fcribe AC in one minute, the motion AC is the change
which it has fuftained. The motion Ab is not the
change : for if AF had been the primitive motion, the
fame motion A b would have been the refult of com¬
pounding with it the motion AG. But fince AF is
different from AB, the fame change cannot produce
the lame new conditions. But, farther, there is no
other motion which, by compounding it with AB, will
produce the motion A b j and the motion AC is the
only circumftance of famenefs between changing the
motion AB into the diagonal motion A b, and giving
the motion AC to a body which was previoufly at reft.
—From thefe conditions it follows, that a change of
motion, is that motion, which by compoftion with the
previous fate of motion, produces the new motion.
54. This compofition of motion has been confidered ancl 'n an0"
in a different wray. While a body is fuppofed to movether vvay’
uniformly in the dire&ion AB, the fpace in which this
motion is performed, is fuppofed to be carried in the
direction AC. But it cannot be conceived that any
portion of fpace is moved from its place. A diftindft
notion of this compofition may be obtained, by fuppo¬
fing a perfon walking along a line AB, wEile this is
drawm on a piece of ice, and the ice is floating in the
direftion AC. But the motion on moving ice is not
precifely a compofition of two determinations to mo¬
tion ; for this is completed in the firft inftant. When
the motion in the direftion and with the velocity A b
begins, no further exertion is needed ; the motion con¬
tinues, and Ab is defcribed. It ferves, however, to
exhibit to the mind the mathematical compofition of
twTo motions. In the refult of this combination, all the
characlerillics of the twro determinations are to be
found ; for the point of interfedlion, in whatever way
it is confidered, partakes of both motions.
55. Thus a general characleriftic of a change of
motion is obtained, and this correfponds with the mark
and meafure of every moving caufe ; for it is the very
motion which it is conceived to produce. It may per¬
haps even be confidered as the foundation of former
mealures ; for in every acceleration, retardation, or de¬
flection, there is a newr motion compounded wdth the
former*
Sea. II. D Y N A
Compound former. What is taken for the beginning of motion in
Motions, every obfervation of furrounding bodies, is nothing
^ ' more than a change induced on a motion already pro¬
duced.
56. The a£liv,i compofition of motion being fo ge¬
neral in the phenomena of the univerfe, it obtains in
all motions and changes of motion produced or obfer-
ved, and the character!ftic which has been affumed of
a change of motion being the fame, whatever may
have been the previous motion, and this being equally
applicable to fimple motions, it is evident that a know¬
ledge of the general refults of this compofition of mo¬
tion will be of efiential fervice in acquiring a know¬
ledge of mechanical nature.
57. The following is the general theorem to which
all others may be reduced.
Prop. IX.
Two uniform motions, having the dire&ions and ve¬
locities reprefented by the fdes AB, AC, of a parallelo¬
gram, compofe a uniform ?notion in the diagonal. The
demonflratxon of this has been already given. The
motion of the point of interfection of thefe two lines,
each moving uniformly in all its points, in the direc¬
tion of the other, is, in every inftant, compofed of the
two motions. It is the fame as if a point defcribed AB
uniformly, while AB is carried uniformly in the di-
reflion AC. This motion is along the diagonal A b,
and it has been already fhewm to be uniform. And,
becaufe AB and A b are defcribed in the fame time,
the velocities of the motions along AB, AC, and A b
are proportional to thofe lines.
Corollaries.
Cor. 1. The motion A b, which is compounded of the
two fimple motions AB and AC, is in the fame plane
with thefe motions. For a parallelogram lies all in the
fame plane.
Cor. 2. The motion A b may be produced by the ccm-
pojition of any two uniform motions having the direfiion
and velocities which are reprefented by the Jides of any
parallelogram AF b G, or AC b B, which has A b for
its diagonal.
How toaf- 58. Cafes are not unfrequent in which the directions
certain the 0f two fimple motions compofing an obferved motion
of^heTe*1 171 ay ko difcovered ; but the proportion of the veloci-
locity in t7es unknown. This velocity may be afcertained by
compound means of this laft propofition. For the direfiion of the
motions. three motions, namely, the twro fimple and the com¬
pound motions, determines not only the fpecies of pa¬
rallelogram, but alfo the ratio of the fides. Again, in
thofe cafes in wdiich the direfiion and the velocity of
one of the fimple motions are known, and therefore its
proportion to that of the obferved compound motion,
the direfiion and velocity of the other may be alfo
found by means of the fame propofition; becaufe from
thefe data the parallelogram may be determined.
59. This motion in the diagonal is called the equi¬
valent motion, or the refilling motion ; for it is equiva¬
lent to the combined motions in the fides. Thus, if
the moving body firfl defcribe AB, and then B b or
AC, it will be in the fame point, as if* it had defcrib¬
ed A b, namely, in the point b.
60. It is often highly ufeful in invefligations of this
kind to fubflitute fuch motions for an obierved motion,
M I C S.
47
as wall produce it by compofition. This has been de- Compbur.
nominated the reflation of motions. By this manner , Motion..
of proceeding, a fhip’s change of fituation at the end of
a day, having failed in different courfes, is computed.
Thus the diflance failed to the eaflward or the weft-
ward, as well as that to the northward or fouthward,
on each courfe, is obferved and marked. The whole of
the callings, and the whole of the fouthings, are add¬
ed together and then it is fuppofed that the fliip has
failed for the whole day on that courfe, which would
be produced by combining the fame eafting and fouth-
ing.
61. It is alfo ufeful to confider how much the body
has been advanced in a certain diredlion by means of
the obferved motion 5 let us fuppofe in the direfiion
AB (fig. 10.) The motion CD is firfl confidered as
compofed of a motion CE parallel to the given line
AB, and another motion CF perpendicular to AB.
CD is the diagonal of a parallelogram CEDF, one of
wrhofe fides CE is parallel to AB, and the other CF
is perpendicular to AB. It is evident, that the body
has advanced in the direfiion of AB as much as if it
had moved from G to H, inflead of moving from C to
D, fo that the motion CF has no effeft either in ob-
flrufling or promoting the progrefs in AB. This is
called efimating a motion in a given direfiion, or re¬
ducing it to that direfiion.
62. A motion is alfo faid to be eflimated in a given
plane, when it is confidered as compofed of a motion
perpendicular to the plane, and of another parallel to
it. In a given plane ikBCD (fig. n.), let EF be a
motion compounded of a motion GE perpendicular to
the plane, and EH parallel to it. For if the lines
GE, FH are drawn perpendicular to the plane, they
cut it in two points e and f, and EH is parallel to e f.
63. In the fame wray a compound motion may be
formed of any number of motions. Let AB, AC, AD,
AE’, &c. (fig. 12.) be any number of motions, of which
the motion AF is compounded. The motion which is
the refult of this compofition is thus afcertained. The
motion AG is compounded of AB and AC 5 and the
motion AG compounded with AD, gives the motion
AH; which latter being compounded with AE, pro¬
duces the motion AF. And the fame place, or final
fituation F, will be found by fuppofing the different
motions AB, AC, AD, AE, to be performed fuccef-
fively. The moving body firft defcribes AB $ then
BG, equal and parallel to AC j then GH, equal and
parallel to AD 5 and laftly, HF, equal and parallel to
AE. In this cafe it is not requifite that all the mo¬
tions lie in the fame plane.
64. Three motions which have the direfiion and
proportions of the fides of a parallelepiped, compofe a
motion having the direfiion of its diagonal. Let AB,
AC, AD (fig. 13.), be thefe motions, the compound¬
ed motion is in the diagonal AF of tire parallelepiped j
becaufe AB and AC compofe the motion AE j and
AE and AD compofe the motion AF.
It is in this way that the mine-furveyor proceeds.
He fets down a gallery of a mine, not direflly by its
real pclition, but marks the ealting and welling, the
northing and fouthing, as well as its dip and rife. All
thefe meafures are referred to three lines, of which one
runs ealt and weft, one north and fouth, and a third is
perpendicular. Thefe three lines are obvioufty analo¬
gous
w
472 I> Y N A'
Coivpound goys to the angular boundaries of a rectangular box,
, Mot Gr-- , as AC, AB, AD.
Other om- Che compofition of uniform motions only has
pou, (1 mo- yet been confidered. But it is eafy to conceive that
tions. any motions may be compounded. It is a cafe of this
kind when a man is fuppofed to walk on a field of ice
along a crooked path, while the ice floats down a
crooked ftream. Suppofe a uniform motion in the di¬
rection AB (fig. 14.), to be compounded with a uni¬
formly accelerated motion in the direction AC. A
Itone falling from the malt head of a Ihip, while the
fails uniformly forward in the direction AB, affords an
example of this kind of motion $ for the ftone will be
obferved to fall parallel to a plummet hung from the
malt head. But the real motion of the ftone is a pa¬
rabolic arch A b fg, which AB touches in A; for
while the maft head defcribes the equal lines AB, BF,
FG, the ftone has fallen to /3 and 0 and y, and the
line AC is in the pofitions BB', FF', GG', fo that A<p is
four times A /3 j and A y is nine times A /3. There¬
fore A£, As, Ay, are as the fquares of /3 b, q>f ygt
and the line A bfg is a parabola.
Condition 66. Knowing the direction and velocities of each of
of com- the Ample motions in any inftant, of which two mo-
rions diTo* t*ons» however variable, are compounded, we may dif-
vered from cover ^e direction and velocities of the compound
that of the motions in that inftant. For it may be fuppofed that
Ample mo- each motion at that inftant proceeds unchanged : a
tions. parallelogram is then conftruCted^ the fides of -which
have the directions and proportions of the velocities of
the Ample motions *, and the diagonal of this parallelo¬
gram will exprefs the direction and velocity of the
compound motion. But on the other hand, if the
direction and velocity of the compound motion, with
the directions of each of the Ample motions, be known,
we may difcover their velocities.
67. In cafes where a curvilineal motion as ABC
.(fig. 15.), is the refult of two motions compounded,
of which the direction is known to be AD and AE,
we difcover the velocities of the three motions in any
point B, by drawing the tangent BF, and the ordinate
BG, parallel to one of the Ample motions, and from
any point H in that ordinate drawing HF parallel to
the other motion, and cutting the tangent in the point
F. The three velocities are in the proportion of the
three lines FH, HB, and FB.
Banger of 68. As the motions which are obferved in nature
miftakes are very different from what they are taken to be, it
a7ut f is not eafy to avoid miftakes with refpeCt to the changes
oiotion. motion, and confequently with refpeft to the infer¬
ence of its caufe. Without confidering the real mo¬
tion of any body, we are apt to judge only of the
change of diftance and direClion in relation to our-
felves. Thus it is that our inferences with regard to
the planetary motions are very different from the mo¬
tions themfelves, if the rapid motion of our earth be
confidered.
Prop. X.
69. Th* motion of one body in relation to another
■hody, or as it is feen from another body, which is alfo
in r ation, is compounded of its own real motion, and
the oppofite of the real motion of the fecond body.
Let A (fig. 16.) be a body in motion from A. to C,
as feen from B, which is another body in motion from B
M I C S. Part I.
to D the motion of A is compounded of its ovm real Motions
motion, and of the oppofite to the real motion of B.
Join AB, and draw AE equal and parallel to BD.,
Complete the parallelogram ACFE, and join ED and
DC. Produce EA, and make AL equ.*! to AE or BD.
Complete the parallelogram LACK, and draw AK
and BK. If then A had moved along AE w'hile B
moves along BD, the twro bodies would have been at
E and D, at the fame time, and wmuld have the fame
relative fituation j they wrould have the fame bearing
and diftance as before. And if the fpe&ator in B is
not fenlible of his own motion, A will appear not to
have changed its place. In the fame way twm fhips
becalmed in an unknown current, feem to the perfons
on board to be at reft. The real pofition, therefore,
and diftance DC, are the fame with BK j and if a
fpe&ator in B imagines himfelf at reft, the line AK
w'ill be taken as the motion of A. And this motion,
it is obvious, is compofed of the motion AC its real
motion, and the motion AL which is the equal and
oppofite motion to that of BD.
Again, if BH be drawn equal and oppofite to AC,
and the parallelogram BHGD be completed, and BG
and AG be drawn, the diagonal BG will be the mo¬
tion of B as it is feen from A. Now as KAGB is a
parallelogram, the relative fituation and diftanqes of A
and B at the end of the motion will appear to be the
fame as in the former cafe. For B appears to have
moved along BG, which is equal and oppofite to AK.
Hence it follows, that the apparent or relative motions
of twm bodies are equal and oppofite, whatever their
real motions may be; and therefore they do not afford
any information of their real motions.
70. Suppofe equal and parallel motions are com¬
pounded with all and each of the motions of any num-.
ber of bodies, moving in any manner of wray, then
their relative motions are not confequently changed.
For if it be compounded with the motion of any one
of the bodies which may be called A, the real motion
of this body is changed *, but its apparent motion as
feen from another body B, is compounded of the real
change, and of the oppofite to the real change in A,
which therefore deftroys that change, and the relative
motion of A is the fame as before. Thus it is that
the motions in the cabin of a ftiip are not affe&ed by
the fhip’s progreflive motion j and the motion of the
'earth round the fun produces no perceptible effe& on
the relative motions on its furface. And indeed it is
only by obferving other bodies which are not affe&ed
by thefe common motions, and to which wre refer as
to fixed points, that we arrive at any knowledge of
them.
Sfxt. IV. Of Motions continually Defected.
71. CURVILINEAL motions are cafes of continual de-Great va-
fle&ion. They are fufceptible of grett varieties j andutty of
the inveftigation of their modifications and chief pro-cu:vli,nea*
perties is attended with no fmall difficulty. Uniform ll0U'Jn:'’
motion in a circular arch is an example of tht iimpleft
cale of curvilineal motion j for here the delle&icns from
re&ilineal motion are equal in equal times. If, how¬
ever, the velocity be increafed, the momentary dc-
fie&ion muft alfo be augmented j for a greater arch
will be defetibed, and the end of this greater arch is
at
Sea. IV. t> Y N A
Motions at a greater diftance from tlie tangent. But the pro-
continually portion of this augmentation is ditficult to be afcer-
, tained.
^ When a uniform reailineal motion AB (fig. 17.) is
defledfed into another BC, the linear defle&ion is as¬
certained by drawing a line from the point c^ at which
point the body would have arrived, had it not been
defle&ed to the point C at which it has arrived. The
refult is the fame, whether the lines d D or c C be
drawn in this manner j for being proportional to B c/,
B c, they always give the fame meafure of the veloci¬
ties ; and here the lines of deflection are all parallel,
1 indicating the diredtion of the defledtion in the point
B. But this is not the cafe in any curvilineal motion.
It rarely happens that c/ D, c C, are parallel ; and it is
never found that </I) : cC^iBt/ : Be. We cannot
therefore difeover which lines fhould be taken for the
indication of the diredtion of the defledtion at B, or for
the mealure of its magnitude. A greater velocity then,
in the fame curve, produces a greater defledlion , but
if the path be more incurvated, an arch of the fame
length deferibed with the fame velocity, caufes a far¬
ther deviation from the tangent. If therefore a body
have a uniform motion in a curve of variable curva¬
ture, the defledlion is greateft where the curvature is
greateft.
Thus it appears that the diredlion and meafure of the
deflections by which a body deviates continually into a
curvilineal path cannot be afeertained, but by invefti-
gating the ultimate pofitions and ratios of the lines,
which join the points of the curve with the fimultaneous
points of the tangent, as the points 5 and C are taken
nearer to B. In fome cafes, but rarely, the lines join¬
ing the fimultaneous points are parallel. But in moil
cales the diredlion of the defledlion is difeovered by
obferving to what diredlion it approximates. The fol¬
lowing propofition wjiich was difeovered by Newton is
of great importance in this inveftigation.
Prop. XI.
72. If a body deferibe a curve line ABCDEF (fig.
18 .) being in the fame plane, and if in this plane there
be a point S fo ftuated, that the lines SA, SB, SC, &c.
drawn to the curve, cut off areas ASB, ASC, ASD,
&c. proportional to . the times of deferibing the arches
AB, AC, AD, &c. then the defkiiions are always di-
reSled to the point S.
Suppofe firfl: that the body deferibes the polygon
ABCDEF, formed of the chords of this curve, and
that it deferibes each chord uniformly, and is defledled
only in the angles B, C, D, &c. Suppofe alfo that
the fides of the polygon are deferibed in equal times,
fo that, according to the hypothefis, the triangles
ASB, BSC, CSD, are all equal. Continue the chords
AB, BC, &c. beyond the arches, making B c equal
to AB, and Qd equal to BC, and fo on. Join c C,
//D, &c. and draw cS, Sd, &c.*, draw C b parallel to
^ B or BA, cutting BS in b, and join b A, and draw
CA, cutting B £ in 0. And laftly, make a fimilar
conftrudlion at E.
Then, becaufe c B is equal to BA, the triangles
ASB and BSc, are equal, and therefore BS c is equal
to BSC. And being on the fame bafe SB, they are
therefore between the fame parallels ; that is, c C is
Vol. VII. Part II.
M I C S. 475
parallel to BS, and BC is the diagonal of a parallelo- Motions
gram B £ C c. The motion BC is therefore compound-
ed of the motions B c and B b, and B is the deflec- 1,, .... ,)
tion, by which the motion B c is changed into the mo¬
tion BC ; and therefore the defleftion in B is directed
to S. By fimilar reafoning it may be fhown that/F,
or E i, is the deflexion at E, and is likewife directed
to S 5 and the fame demonftration wall apply to every
angle of the polygon.—This point S has been called
the centre of defledtion.
If the Tides of the polygon are diminithed, and their
number infinitely increafed, the demonfiration remains
the fame, and continues, when the polygon coalefces
wdth the curvilineal area, and its fides with the curvi¬
lineal arch.
But when the whole areas are proportional to the
times, equal areas are deferibed in equal times. In fuch
motion therefore, the deflections are always directed
to S.
Prop. XII.
73. If the defleElion by which a curve line is deferib*
ed, be continually dire&ed to a fixed point, the figure
will be in one plane, and areas will be deferibed round
that point proportional to the times. Let ADF be the
curve line deferibed, and let the deflediions be diredled
to the point S, this curve line is in the fame plane.
For BC is the diagonal of a parallelogram, and is in
the plane of SB and Be j and e C is parallel to BS,
and the triangles SBC, SB c, and SB A, are equal. But
equal areas are deferibed in equal times ; and therefore
areas are deferibed proportional to the times.
Corollaries.
74. Cor. 1. The velocities in different points of the
curve are inverfely proportional to the perpendiculars
S r and S t (fig. 19.) drawn from S on the tangents
A r, E t in thefe points of the curve. For fince the ele¬
mentary triangles ASB, ESF, are equal, their bafes
AB, EF, are inverfely as their altitudes S r, S /. And
thefe bafes being deferibed in equal times are as the
velocities, and ultimately coincide with the tangents at
A and E and therefore the velocity in A is to that
in E as S £ to S r.
Cor. 2. The angular velocities round S are inverfely
as the fquares of the difiances. For if we deferibe round
the centre S the fmall arches B a, F they may be
confidered as perpendicidars on SA and SE. Deferibe
alfo with the diftance SF the arch g h. It is evident
that j // is to F £ as the angle ASB to the angle ESF.
And fince the areas ASB, ESF are equal, we have
B a : F $=SE : SA.
But g h : B a—SE : SA
Therefore g h \Y 3s: SE2 : SA2
And ASB : ESF=SE2 : SA*.
75. Let us now proceed to determine the magnitude
of the deflexion, or to compare its magnitude in any
two points, as for example the magnitude in B (fig.
18.) wdth its magnitude in E. The deflection in B is
to that in E as the line B to the line E i; for B b
and E i are the motions, wdiich, by being compounded
w ith the motions B c and E^/make the body deferibe
BC and EF. And therefore when the fides of the po-
3 O lygon
474
B Y N A
, ^Jotlor‘'' iygon are infinitely dimimflied, the ultimate ratio of
CiiS.eaedy B/'to E 1 is lhe ratio of the dcfleftion at B to the de-
sA-- fleftion at E.
1 o obtain a convenient expreflion of this ultimate
ratio, let ABCXZY be a circle which paffes through
the points A, B, C. Draw BSZ through the point S,
and draw CZ, AZ. Now the triangles BC£ and AZC
are fimilar, for C t> w?as drawn parallel to c B or BA j
and therefore the angle C B is equal to the alternate
angle b BA or ZBA, which is equal to the angle
ZCA, becaufe it is fubtended by the fame chord ZA j
and becaufe they Hand on the fame chord CZ, CB b,
or CBZ, is ec^ual to CAZ. And therefore the re¬
maining angles b CB and CZA are equal, and the tri¬
angles are fimilar. Therefore B b : CAzirBC : AZ.
Now if the fides of the polygon are continually di-
minilhed, the points A and C continually approach to
B, and CA continually approaches to c A, or to 2 c B,
or 2 CB, and is ultimately equal to it j and AZ is ul¬
timately equal to BZ.
Thererore ultimately, B£ : 2 BCrzBC : BZ, and
B^xBZ=2 BC% and B b~^-- .
BZ
Alfo, at the point E, we have E i ultimately equal
2 EF2 .
to £ ^ > ^or E 2 is that chord of the circle through
D, E, and F, which paffes through i.
Therefore B ^ : E i
2BC2 2 EF*
BZ E « ’
The ultimate circle, when the three points A, B, C,
coalefce, is called the circle of equal curvature, or the
cquicurve circle, which coalefces with the curve in B
in the clofert manner 5 and the chord BZ of this circle,
having the diredlion of the defleftion in B, is called its
defeclive chord. And finco. BC and EF are deferibed
in equal times, they are proportional to the velocities
in B and E. This propolition therefore may be expref-
fed as follows.
In curvihneal motions, the defeEhons in different points
o f the curve, are proportional to the fquare of the velo¬
cities in thofe points diredlhj, and to the defective chords
of the equicurve circles, invcrfe/i/.
It ought hovvever, to be remarked, that this theorem
is not limited to curvilineal motions, in which the de-
hefHons tend always to the fame fixed point j it may
be extended to all curvilineal motions whatever. A
lymbolical exprefiion of this theorem will be conveni¬
ent. If therefore the deflective chord of the equicurve
circle be reprefented by c, and the deflection by d,
the theorem may be thus expreffed.
, . v* ,2 arch*
Q . or d~ .
• e7 c
76. The line B b is the linear deflection by which
the uniform motion in the chord AB is changed into a
uniform motion in the chord BC, or it is the deviation
c C from the point to which the moving body would
have arrived, if the defleCtion at B had not taken place.
In the cafe of eurvilineal motion which w e are now
confidering, the lines B b and B c are expreflions of
the meafures of the velocities of thefe motions. B c is
to B £ as the velocity of the progreffive motion is to
the velocity of the defle&ion, generated in the time
that the arch BC is deferibed. But the defieCHon in
the arch has been continual, and like acceleration, it
M I C S. part jp
may be meafured by the velocity generated during any Motions
moment of time. It may therefore be meafured by the confinuaJ]y
velocity generated during the time the arch BC is de- , defleaed.'
feribed. This meafure will therefore be double of the v ~
fpace through which the body is aftually defleaed from
the tangent in B in that time. The fpace deferibed
will be BO, or only one-half of B b. This is exadly
what happens 5 for the tangent is ultimately parallel to
OC, and it biiedls c C j therefore the velocity gradu¬
ally generated is that which conftitutes the polygonal
motion in the chords, although the defledtion from the
tangent to the curve is only half of the defleftion from
the produced chord to the curve.
77. In any point of a curvilineal motion, the veloci¬
ty is that which w’ould be generated by the defledlion
in that point, if continued through one-fourth of the
defledlive chord of the equicurve circle. Take x for
the fpace along which a body is to be accelerated that
it may acquire the velocity BC.
We have B£*, or 4 BO : BC*=rB : a (37.—1.) 5 and
BO : BCrrBC : 4.1
therefore #—4 BZ.
__ BC* , BC*
,~4BO’ and 4 ‘V ~B0’ °r'
But BO : BC=BC : BZ >
78. We have now obtained charadteriftic expreflions,
or marks and meafures of the principal affedlions of
motion. Thefe expreflions may be brought into one
view7 as follows.
The acceleration a is ^ (48.), or ^(49.), or 4-
t s p
(42.).
The momentary variation of velocity v—a t (48.).
The momentary variation of the fquare of velocity
2 v vz=:2 a s (49.)
The momentary defledtion d
arc.*
chord
(760
The defledlive velocity=—(75-)*
79. But for the application of thefe do&rines, it is
neceffary to feledt fome point in any body of fenfible
magnitude, or in any fyftem of bodies, by whofe pofi-
tion or motion, a diftindl and accurate notion of the po-
fition or motion of the body or fyfiem may be formed.
The condition by w'hich the propriety of this feledlion is
afeertained, is, that the pofuion, difance, or motion
this point fhall be the medium or average of the poflions,
difances, and motions of every particle of matter in the
aggregate or fyftem.
This will happen, if the point be fo fituated, that Center of.
when a plane is made to pafs through it in any direc-pofitiom
tion whatever, and perpendiculars being drawn to this,
plane from every particle of matter in this aggregate or
fyftem, the fum of the perpendiculars on the one fide
of the plane is equal to the fum of the perpendiculars
on the other fide.. And that fuch a point, which is
called the centre ofpof tion, may be found in every bo-
dy> is proved by the following demonftration.
For let P (fig. 20.) be a point fo fituated, and let
QR be the fedtion of a plane perpendicular to the pa¬
per, and at any diftance from it, the diftance P/> of
the point P from this plane is the average of all the di-
ftances of each particle from it. Let the plane APB
pafs through P, and parallel to QR. The diftance
CS
Sea. IV. r> Y N A
Motions CS of any particle C from the plane QR is equal to
eontinually  J)C, or to Pp—DC. And the diftance GT of
'deflected. ^ a partjcie q on the other fide of APB, is equal to
v HTP+GH, or to P/>-j-GH. Let n be the number of
particles on that fide of AB which is neareft to £)R,
and let o be the number of particles on the other lide
of AB. Let m be the number of particles in the
whole body j we have then It is evident
that the fum of all the diftances of all the particles fuch
as CS, is n X P/1—the fum of all the dillances, fuch as
CD. Alfo the fum of all the dirtances of the particles,
fuchas G, is <?X P/S -p the fum of the diftances GH.
And therefore the fum of both fets is /z + o X ?/>+the
fum of GH— the fum of DC, or //z X P/>+ the fum of
GH—the fum of DC. But by the fuppofed property
of the point P, the fum of GH wanting the fum of DC
is nothing •, and therefore p is the fum of all the
diftances, and P/> is the zzzth part of this fum, or the
average diftance.
Suppofe the body to have changed both its place and
its pofition with refpeft to the plane QR, and that P
(fig. 21.) is ftill the fame point of the body, and <* P /3
a plane parallel to QR. Make p it equal to /> P of
fig. 20. It is plain that P/> is ftill the average diftance,
and that zzz X P /> is the fum of all the prefent diftances
of the particles from QR, and that zz* X ^p is the fum
of all the former diftances. Therefore myY? v is the
fum of all the changes of diftance, or the whole quan¬
tity of motion eftimated in the direction tt P. P tt is
the zzzth part of this fum, and is therefore the average
motion in this direction. The point P has therefore
been properly feleCted j and its pofition, and diftance,
and motion, in refpedft of any plane, is a proper repre-
fentation of the fituation and motion of the whole.
Hence it follows, that if any particle C (fig. 20.)
moves from C to N, in the line CS, the centre of the
whole will be transferred from P to Q, fo that PQ is
the zzzth part of CN j for the fum of all the diftances
has been diminiftied by the quantity CN, and there¬
fore the average diftance muft be diminiihed by the zzzth
CN
part of CN, or PQ is rr .
But it may be doubted whether there is in every bo¬
dy a point, and but one point, fuch that if a plane pafs
through it, in any dircBion whatever, the. fum of all
the diftances of the particles on one fide of this plane
is equal to the fum of all the diftances on the other.
It is eafy to ftiew that fuch a point may be found,
with refpeft to a plane parallel to QR. For if the fum
of all the diftances DC exceed the fum of all the di¬
ftances GH, we have only to pafs the plane AB a little
nearer to QR, but ftill parallel to it. This will diminilh
the fum of the lines DC, and increafe the fum of the
lines GH. We may do this till the fums are equal.
In like manner we can do this with refpe£t to a
plane LM (alfo perpendicular to the paper), perpendi¬
cular to the plane AB. The point wanted is fonae-
where in the plane AB, and fomewhere in the plane
LM. Therefore it is fomewhere in the line in which
thefe two planes interfeft each other. This line paffes
through the point P of the paper where the two lines
AB and LM cut each other. Thefe two lines repre-
fent planes, but are, in faft, only the interfecftion of
thofe planes with the plane of the paper. Part of the
body muft be conceived as being above the paper, and
M I C S, 475
part of it behind or below the $aper. The plane of Motions
the paper therefore divides the body into two parts. It0”"^^^
may be fo fituated, therefore, that the fum of all the .
diftances from it to the particles lying above it ftiall be
equal to the fum of all the diftances of thofe which are
below it. Therefore the fituation of the point P is
now determined, namely, at the common interfeflion of
three planes perpendicular to each other. It is evident
that this point alone can have the condition required
in refpedl of thefe three planes.
It ftill remains to be determined whether the fame
condition will hold true for the point thus found, in
refpeft to any other plane pafling through it j that is,
whether the fum of all the perpendiculars on one fide,
of this fourth plane is equal to the fum of all the per¬
pendiculars on the other fide.
Let AGHB (fig. 22.), AXYB, and CDFE, be
three planes interfering each other perpendicularly in
the point C j and let CIKL be any other plane, inter¬
fering the firft in the line Cl, and the fecond in the
line CL. Let P be any particle of matter in the body
or fyftem. Draw PM, PO, PR, perpendicular to the
firft three planes refperively, and let PR, when produ¬
ced, meet the oblique plane in V; draw MN, ON,
perpendicular to CB. They will meet in one point Ni
Then PMNO is a rerangular parallelogram. Alio
draw MQ perpendicular to CE, and therefore parallel
to AB, and meeting Cl in S. Draw SV ; alfo draw
ST perpendicular to VP. It is evident that SV is
parallel to CL, and that STRQ and STPM are rect¬
angles.
All the perpendiculars, fuch as PR, on one fide of
the plane CDFE, being equal to all thofe on tile other
fide, they may be confidered as compenfating each
other •, the one being confidered as pofitive or additive
quantities, the other as negative or fubtra£tive. There
is no difference between their fums, and the fum of
both fets may be called o or nothing. The lame muft '
be affirmed of all the perpendiculars PM, and of all the
perpendiculars PO.
Every line, fuch as RT, or its equal QS, is in a cer¬
tain invariable ratio to its correfponding QC, or its
equal PO. Therefore the pofitive lines RT are com-
penfated by the negative, and the fum total is
nothing-.
O # m
Every line, fuch as TV, is in a certain invariable
ratio to its correfponding ST, or its equal PM, and
therefore their fum total is nothing.
Therefore the fum of all the lines PV is nothing j
but each is in an invariable ratio to a correfponding
perpendicular from P on the oblique plane CIKL.
Therefore the fum of all the pofitive perpendiculars on
thi$ plane is equal to the fum of all the negative per¬
pendiculars, and the propofition is demonftrated, viz.
fhat in every body, or fyftem of bodies, there is a point
fuch, that if a plane be paffed through it in any direct
tion whatever, the fum of all the perpendiculars on one.
fide of the plane is equal to the fum of all the perpen¬
diculars on the other fide.
80. If A and B (fig. 23.) be the centres of pofition
of two bodies, whpfe quantities of matter (or numbers
of equal particles^ are a and b, the centre C lies in the
ftraight line joining A and B, and AC : CBrr^ : a,
or its diftance from the centres of each are inverfely as
their quantities of matter. For let * C £ be any plane
3 O 2 pafling
476 D Y N A
Of Movirig paffing through C. Draw A «, B/3, perpendicular to
. 1'0^ccs- , this plane. Then we have </xA« = ^xB/3, and
A * : B (Z>~b : a, and, by limilarity of triangles, C A :
CB“Z» : a.
If a third body D, whofe quantity of matter is
be added, the common centre of pofition E of the three
bodies is in the flraight line DC, joining the centre D
^of the third body with the centre C of the other twro,
and DE : JLC — a-\-b : d. For, palling the plane
2 E * through E, and drawing the perpendiculars D 5,
C x, the fum of the perpendiculars from D is </x D 2 ;
and the fum of the perpendiculars from A and B is
«+£xC*, and we have </x D -j-£ x C x ; and
therefore DE : JLC—a-\-b : d.
In like manner, if a fourth body be added, the com¬
mon centre is in the line joining the fourth with the
centre of the other three, and its dillance from this
centre and from the fourth is inverfely as the quantities
of matter ; and fo on for any number of bodies.
81. If all the particles of any fyllem be moving uni¬
formly, in ftraight lines, in any direflions, and with
any velocities whatever, the centre of the fyllem is
either moving uniformly in a ftraight line, or is at
reft.
For, let in be the number of particles in the fyfteru.
Suppofe any particle to move uniformly in any direc¬
tion. It is evident from the reafoning in a former pa¬
ragraph, that the motion of the common centre is the
wzth part of this motion, and is in the fame diredftion.
The lame muft be faid of every particle. Therefore
the motion of the centre is the motion w hich is com¬
pounded of the ml\i part of the motion of each par-
M I C S. ‘ Part II.
tide. And becaufe each of thefe w'as fuppofed to be Of Moving
uniform and redilineal, the motion compounded of, Forces,
them all is alfo uniform and redilineal j or it may hap- ^
pen that they wall fo compenfate each other that there
will be no diagonal, and the common centre will remain
at reft.
Corollaries.
82. Cor. 1. If the centres of any number of bodicr
move unifonnly in freight lines, whatever may have
been the 7notions of each particle of each body, by rvta~
tion or otherwife, the motion of the common centre will
be uniform and reBilineal.
Cor. 2. The quantity of 7iiotion of fuch a fyf ern it
the fum of the quantities of motion of each body, reduced
to the direBion of the centre''s motion. And it is had by
multiplying the quantity of matter in the fyfem by the
velocity of the centre.
Cor. 3. The velocity of the centre is had by reducing
the motion of each particle to the direBio7i of the centre's
7notion, and then dividing the fu7ti of thofe reduced mo¬
tions by the quantity of 7natter in the fyfem.
83. If on any twro bodies of fuch an affemblage
equal and oppolite quantities of matter be impreffed,
the motion of the centre of the whole is not at all af
feded by it. Becaufe the motion of the centre, arifing
from the motion of one of the bodies being compound¬
ed with the equal and oppolite motion of the diagonal
of the parallelogram, becomes a point j or thefe mo¬
tions deftroy one another, and therefore no change is
effeded on the motion of the centre.
PART II. OF MOVING FORCES.
Gbjed of
dynamics.
84. HAVING in the former part conlidered the
general dodrine of motion, which is the foundation of
mechanical inveftigations, we now proceed to treat of
moving forces or dyna7nics, properly fo called.
It has been already obferved, that dynamics includes
the abftrad dodrine of moving forces, or the neceffary
refults of the relations of our thought concerning mo¬
tion, the immediate caufes of motion, and its changes ;
and that from the changes obferved, we infer agency
in nature 5 and in thefe changes we are to dilcover
what we know of their caufes.
85. When we call our eyes around us, it cannot ef-
cape obfervation, that the changes which we perceive
in the ftate or condition of any body in refped of mo¬
tion, are conftantly and diftindly related to the fitua-
tion and diftance of other bodies. The motions of the
moon, or of a ftone projeded through the air, have a
palpable relation to the earth $ the motions of the tides
have alfo an obvious relation to the moon 5 and the
motions of a piece of iron have a palpable dependence
on a magnet. The vicinity of the one of thefe bodies
feems to be the occalion, at leaft, of the motions of
the other 5 and the caufes of thefe motions have an evi¬
dent connedion with, or dependence on, the other bo¬
dy. Such dependences have been c; lied the mechani¬
cal relations of bodies. They are indications of pro¬
perties or diftinguilhing qualities. They accompany
the bodies wherever they are, and are ufually conceiv¬
ed to be inherent in them. They at lead; afeertain and
determine what is called the mechanical nature of bo¬
dies.
86. The mutual relation of bodies is differently con-Mutiml re¬
ndered according to the intereft we may have in the lation of
phenomenon. The caufe of the approach of the iron dif-
to the magnet is generally aferibed to the magnet. It ^fidered.
is faid to attrad the iron. The approach of a ftone to
the earth is aferibed to the ftone. It is faid to tend to
the earth. But it is probable that the procedure of
nature is the fame in both ; that both bodies are ah
feded alike, and that the property is diftindive of
both. For in all cafes that have been obferved, the
indicating phenomenon is equally conneded with both
bodies j as in the cafe of magnetifm the magnet and
the iron approach each other j and an eledrified bo¬
dy and another body near it approach each other. This
property is therefore equally inherent in both bodies,
between which there is a mutual attradion. But, ac¬
cording to fome philofophers, no fuch mutual tenden¬
cies exift either in the one body or the other. The
obferved approaches or mutual feparations of bodies, or
their attradions and repulfions, are fuppofed to depend
on the extraneous adion of an ethereal fluid.
87. Thefe qualities thus inherent in bodies, wrhich Powers,
conftitute their mechanical relations, or the mechanical&c*
affedions of matter, have been called powers ox forces.
The event which is indicated by their prefence, is con-
fideied
Forces.
Part II. - D Y N A
Of Moving fidered as the effecl and mark of their agency. _ Thus
the magnet is faid to aci on the iron, the earth is laid
' to atl on the ftone which falls to its furface ; and the
iron and the ftone are faid to a<ft on the magnet and
the earth. But all this, it muft be obferved, is figu¬
rative language. Power, force, and aEhon, when uled
in their original ft rift: fenfe, exprefs. only the notions ot
the power, force and aftion of fentient, aftive beings j
and cannot be predicated of any thing but the exertions
of fuch beings } for fuch beings only are agents. In
ftridl propriety, it is perhaps only the exerted influence
of the mind on the body which ought to be called ac¬
tion. Language having begun among fimple men,
fuch denominations were very properly given to their
own exertions } becaufe to move a body they found it
neceffary to exert their force or power, or to a£t. But
when the changes of motion, obferved in the occur¬
rence or vicinity of bodies, were attended to by fpecu-
lative men, and it was found that the phenomena great¬
ly refembled the refults or effefts when they exerted
their own ftrength, fimilar terms were employed to ex-
prefs thefe occurrences in nature. The old term was
retained, in preference to the invention of a new lan¬
guage, to exprefs things which had fo near a refem-
blance. The danger of confounding things from the
ufe of the fame terms, was avoided from the differences
in other circumftances of the cafe. It is not, however,
to be imagined, that they fuppofed inanimate ^ bodies
exerted force or ftrength in the fame way as living be¬
ings. But, in the progrefs of refinement, the word
power or force came at laft to be employed to exprefs
any efficiency whatever; and hence the common ex-
preflions, the force of arguments, the affion of mo¬
tives, the power of an acid to diffolve a metal, &c. It
is to this idea of conveniency, that the ufe of the terms
attradian, repulfon, preffure, vnpulfion, as well as of
the words power and force, which exprefs efficiency^ in
general, is to be afcribed. But thefe terms, excepting
in thofe cafes when they are applied to the exertions
or actions of living beings, are metaphorical. On ac¬
count, however, of the refemblance between the pheno¬
mena and thofe which are obferved when wre draw a-
thing toward us, pufh it from us, forcibly comprefs it,
or kick it awuy, thefe different actions being analogous
to attraction, repulfion, preffure, and impullion, thefe
words are employed as terms of diftin£tion. 'I he ac¬
tion of the mind on the body is perhaps the only cafe
of pure unfigurative aftion. But this action being al¬
ways exerted with the view of effefting fome change on
external bodies, our attention is only direTed to- them.
The inftrument paffes unnoticed ; and hence it L faid
that we a£t on the external body. The real aftion is
only the firft movement in a long fucceffion of events,
and is only the remote caufe of the interefting event.
In many cafes of mechanical phenomena, we find the
x;efemblance to fuch aftions to be very ftrong. The
following is of this defcription. A ball is proje&ed
from a man’s hand by the motion of his arm 5 and in
the fame way a ball is impelled by the unbending of a
fpring. In all circumftances there is a refemblance be¬
tween thefe two events, excepting in the aftion of the
mind on the corporeal organ. And, hence in general,
fcecaufe the ultimate refults of the mutual influence of
bodies on each other have a ftrong refemblance to the
ultimate refults of our a&iont on bodies, no new or ap-
M I C S. 477
propriate terms have been invented but, as has been Of Moving
already obferved, mankind have remained fatisfied with , ,
the ufe of thofe terms that are employed to exprefs their
own actions, or the exertions of their own powers or
forces.
88. When power or force is fpoken of as exxftmg or Aft Ion of
refiding in a body, and the effect is afcribed to the ex- mechanical,
ertion of this power, one body confidered as poffeiTmg Powers*
it, is faid to aci on another. Thus a magnet is faid to
a£t on a piece of iron j a billiard ball is laid to a6t on
one which it ftrikes. But if it be attempted to fix the
attention on this adtion, independent both of the agent
and the thing adled on, we fhall find that there is no
objett of contemplation. The exertion or procedure of
nature in effecting the change is kept out of view j and
if we limit our attention to the action as a thing di-
ftindl from the agent, we fhall find that it is not the
adtion, ftriaiy fpeaking, but the ad, that is brought
under confideration. And in the fame way, it is only
in the effedt produced that the adtion of a mechanical
power can be conceived.
89. In the very nature of adtion fome change is im-Change im¬
plied. Without producing fome effedt, a man is neverPlied m a«-
faid to ad. Thought is the ad of the thinking principle jtlon‘
and the motion of the limb is the ad of the mind on it.
In mechanics too there i^ adion only in fo far as fome
mechanical effed is produced. For inftance, to begin
motion on a piece of ice, or to Aide along it, we muft
ad violently ; we muft exert force 5 and this force be¬
ing exerted produces motion. In all cafes, the pro-
dudions of motion are conceived as the exertions of
force ; but to continue the motion which has been be¬
gun along the ice, no exertion feems requifite. Be¬
ing confcious of no exertion, wTe ought to infer that
no force is neceffary for the continuation of motion.
It is not the produdion of any new effed, but the per¬
manency or continuation of an effed already produced.
Motion is indeed confidered as the effed of fome ac¬
tion ; but there would be no effed or no change, if
the body were not moving. Motion is not to be conli-
dered as an adion, but the effed of an adion.
90. Mechanical adions or forces have been divided D‘vifion of
into preffitres and impulfxons. The idea of preffure is^e‘Mlca-
very familiar ■, perhaps it enters into every diftind con¬
ception that we can form of a moving force, when the
attention is endeavoured to be fixed on it. Changes
of motion by the collifion of moving bodies are pro¬
duced by impulfion. Preffures and impulfions are ufu-
ally confidered as of different kinds, the adions or ex¬
ertions of different powers. It is fuppofed that there
is an effential difference between preffure and impul¬
fion. That we may obtain all the knowledge that
thefe diftindions can give us, let us ftate fome exam¬
ples of thefe kinds of forces, inftead of attempting to
define or defcribe them..
Let us firft take fome examples of preffure.. Pref-Examploof
fure it is known is a moving force } for if a ball lyingPreirure»
on the table be gently preffed on one fide, it moves to¬
ward the other fide of the table. If it be followed
with the finger, the preffure being continued, its mo¬
tion is continually increafed. There is an acceleration
of its motion. By preffing in the fame way on the
handle of a common kitchen jack, the fly begins to
move ; and if the preffure be continued on the handle,
the motion of the fly becomes very rapid j and there
is*
4?S
DYNAMICS.
Of,Moving is alfo a continual acceleration. Such motions as thefe
. J^CLS* i are the effects of genuine preflure. The unbending of
a fpring would urge the ball in the fame way along the
table, and would produce a continually accelerated
motion; and a fpring coiled up round the axis of the
handle of the jack would, by uncoiling itfelf, urge
round the fly with a fimilar accelerated motion. By
comparing the preflure of the finger on the ball with
the effedls of the fpring, we perceive diftinftly the per-
fedf fimilarity. Theie exertions or aftions, or in¬
fluences, are denoted by the w-ord preffure, which is de¬
rived from the molt familiar inftance of them.
The lame motion may be produced in the ball or
■fly, by pulling the ball or machine by means of a
thread having a weight fufpended to it. Both being
motions accelerated in the fame manner, the aftion of
the thread on the ball or machine comes under the
fame denomination of preflure. Weight is therefore
confidered as a preflmg power. And indeed the fame
compreflion is felt from the real preflure of a man on
the Ihoulders and a load laid on them. But in the
inftance above, the weight acts by the intervention of
the thread. By the prelfure of the -weight it pulls at
that part of the thread to which it is attached, this
part pulls at the next by the force of cohefion j and
this at a third, and fo on, till the moft remote pulls at
the ball or machine. In this way elafticity, weight,
cohefion, and other forces, perform the office of a ge¬
nuine power 5 and their refult being always a motion
beginning from nothing, and accelerating to any velo¬
city by perceptible degrees, from this refemblance we
are led to give them one familiar name.
91. If the thread by which the weight is fufpended
be cut, it falls with an accelerated motion. This alfo
is afcribed to fome preffing power which adts on the
weight ^ and it is even confidered as the caufe of the
body’s weight, which word is a name by which this in¬
ftance of preffing powrer is diftinguiffied. Gravitation,
therefore, comes under the denomination of preflure.
For the fame reafon the attractions and repulfions of the
magnet, or of eledtric bodies, belong to this clafs of
phenomena 5 for on bodies placed between them they
produce adtual compreffions, as well as motions which
are continually accelerated, in the fame way as gravi¬
tation does. To all thefe powers, therefore, the de-
fcriptive name ofpreffuret may be given, although this
name properly fpeaking belongs to one of them only.
This great clafs has been fubdivided by fome philofo-
phers into preffions and folicitations. Gravity is confi¬
dered as a felicitation ab extra, by winch a body is
urged downward. The forces of eledtricity and mag-
netifm, with many other attradlions and repulfions, are
alfo called folicitations. But this claffification feems to
be of little ufe.
92. We h ave a familiar inftance of impulfion in one
ball ftriking another, and putting it in motion. In
this cafe the appearances are very different from the
phenomena of preffure. For the body that is ftruck
acquires in the inftant of impulfe a fenlible quantity of
motion. But after the ftroke this motion is neither ac¬
celerated nor retarded, unlefs by the action of fome
other force. The rapidity of the motion, it is obfer-
ved depends ort the previous velocity of the ftriking
ball. If for inftance a clay ball, moving with any ve¬
locity, ftrike another equal ball which is at reft, the
Part II.
and of im¬
pulfion.
ball which is ftruck moves with one half of the velo- Of Moving
city of the other. It is farther obferved that the ftrik- Forces,
ing ball always lofes as much motion as the ball which '' v
is ftruck gains. From this remarkable fadt there feems
to have arifen an indiftindt notion of a kind of trans¬
ference of motion from one body to another. It is
not faid that the one ball produces motion or caufes it
in the other, but it is faid to communicate motion to it} Communi.
and the phenomenon is ufually termed the communica- cation of
tion of motion. This, however, is a very inaccurate mot‘on'
mode of expreflion. We diftindlly conceive the caufe
or communication of heat, the communication of falt-
nefs, of fweetnefs, and of many other things j but we
have no clear conception of part of the identical mo¬
tion which exifted in one body being transferred to a-
nother. From this, therefore, it appears that motion
is not a thing which can exilt independently, and is
fufceptible of adtual transference *, but is a ftate or con¬
dition of which bodies are fufceptible which may be
produced in bodies, and which is the effedt or cha-
radteriftic of certain natural properties or powers.
Ihe notion of the adtual transference of fomething
formerly poflfeffed by the ftriking body, and now fepa-
rated from it, or transfufed into the body which is
ftruck, has obtained fupport from the remarkable cir-
cumftance in the phenomenon, that a rapid motion re¬
quiring for its production the adtion of a preffing
power, continued for a fenfible, and frequently a long
time, is or feems to be effedted inftantaneoufly by im¬
pulfion. Here then wre find room for the employment
of metaphor, both in thought and language. We fee
the ftriking body affedt the body wffiich is ftruck. It
poffeffes the power of impulfion, or of communicating
motion, but it only poffeffes this power while it is itfelf
in motion ; and w'e therefore conclude that this power
is the efficient diftinguilhing caufe of its motion. Hence
it has been called inherent force, the force inherent in
a moving body, vis infita carport moto. This force is
communicated to the body impelled, or transfufed into
it j the transference is inftantaneous, and the body thus
impelled continues its motion till it is changed by a
new force. But if we attend fcrupuloufly to thofe
feelings which have given rife to this metaphorical
conception, we ftiall find, that although at firft fight
this train of obfervation feems very plauiible, we Ihould
entertain very different notions. To begin the motion
of Hiding on a fmooth piece of ice, we are confcicus of
exertion j but when the ice is very fmooth, no exertion
that we are confcious of feems requifite to continue the
motion. No exertion of power is here neceffary 5 and
therefore we have no primitive feeling of power while
we Aide along. And indeed we cannot think of mov¬
ing forward without effort other wife than as a certain
mode of exiftence. It has however been imagined that
thofe who fupport this opinion have in fome way de¬
duced it from their feelings. To move forward in
walking, we muft continue the exertion with which
we began j and unlefs this power of walking be conti¬
nually exerted, we muft flop our progrefs. But this
is inaccurate obfervation. In the action of walking
there is much more than the continuance in progreflive
motion. It is the repeated and continued lifting the
body up a fmall height, and allowing it to come down
again, and this repeated afeent requires repeated exer¬
tion.
93. From
Part IT.
B Y N A
Impulfe
faid to be
infinitely
greater
than pref-
fure.
Of Moving From the confideration of the inftantaneous pro-
Forces. duSon of rapid motion by impulfe, fome diftinguifhed
philofophers have been led to fuppofe that the force or
power of impullion is not lufceptible of being compa¬
red with a prefTmg power. It has been afferted that
impulfe when compared with preffure is infinitely great.
But the fimilarity of the ultimate refults of impulfe
and preffure, have always led them to adopt a different
view. There is no difference between the motion of
two balls which move with equal rapidity, one. of
which defeends from a height by the force of gravity,
while the other has been ftruck by another body. In
this ftruggle of the mind attached to preconceived opi¬
nions, and at the fame time accommodating thefe opi¬
nions to obferved phenomena, other Angular forms of
exprefiion have arilen. Preffure is confidered as an ef¬
fort to produce motion. And here we have anothei
inftance of metaphorical expreffion as well as thought.
weight of a ball on the table is called a power ,
and this weight is continually endeavouring^ to move
the ball downward. But thefe efforts being ineffe&ual,
the power in this cafe is faid to be dead. It is called
vis mortua, in contradiftincfion to the force of impul-
fion which is called a living power, vis viva. But this
mode of expreffion muff appear very inaccurate, if we
confider the cafe of the impelling ball falling perpen¬
dicularly on the other ball lying on the table. No
motion is induced by this impuliion j and if toe table
be conceived to Hfe annihilated, the power of gravity
becomes a vis viva.
^appofed To prove that impulfe is infinitely greater than pref-
proof. fure, numerous familiar inffances have been adduced by
thofe who fupport tins doctrine. A nail is driven with
a moderate blow of a hammer, which would require a
preffure many hundred times greater than the impelling
effort of the perfon who employs the. hammer. A
hard body may be Ihivered to pieces with a moderate
blow, which would fupport an inconceivable weight
gradually applied. This prodigious fuperiority in im-
pulfion leaves it a difficult matter to account for the
production of motion by means of preffure becaufe
the motion of the hammer might have been acquired
in confequence of the continued preffure of tne carpen¬
ter’s arm. It is confidered as the aggregate of. an infi¬
nite number of fucceeding preffures repeated in every
inftant of its continuance. The fmallnefs of each ef¬
fort is compenfated by their number.
94. After all, it does not appear clear that there are
two kinds of mechanical force, which are effentially dif-
h.iiki3 ui ferent in their nature.. It is, indeed in a great me ale re
mechanical gjven Up p,y thofe who fupport the doctrine that impulfe
*°rce- is infinitely greater than preffure : Some method might
perhaps be found of explaining fatisfa&orily this remark¬
able difference between the two modes of producing
motion. But there feems to be no confiderable advan¬
tage in thus arranging the phenomenon under two di-
ftindt heads.
ulfion 9 5- The nature of tlie fole moving force m nature
the caufe ofhas given rife to much diicuflion among, mechanicians,
motion, and produced no fmall diverfity of opinion. Accord¬
ing to fome, all motion is the effedt of preffure j for
when impulfe is confidered as equivalent to the aggre¬
gate of an infinite number of preffures, every preflure,
however fmall, is fuppofed to be a moving force.
The foie caufe of motion, according to other philofo-
Th«re are
not two
Finds of
M I C S. . 479
phers, is impulfion. Bodies are obferved in motion-, they
impel others, and produce motion in them ; and this , —j
production of motion is faid to be regulated by. .u^n
laws, that there is only one abfolute quantity of. mo¬
tion in the univerfe, wffiich quantity remains invariably
the fame. Some portion of this motion, therefore, mult
be transferred or transfufed when bodies come imo col-
lifion with each other. But befides, theie are fome
cafes in which it is perfeftly obvious that motion pro¬
duces preffure. Cafes, wdiich are indeed both, w-himli-
cal and complicated have been adduced by Euler., to
ffiew that an adlion, in all refpefts fimilar to preflure,
may be produced by motion. Such a cafe is the fol¬
lowing. If two balls are connefted by a thread, they
may be ftruck in fuch a way, that they ftiall not only
move forward, but at the fame time ado wheel round.
When this happens, the thread by which they are con¬
nected is ftretched. Since then, according to this rea-
foning, motion is obferved, and preffure is produced by
motion, it would be abfurd to fuppofe that, preflure is.
any thing elfe than the refult o.f certain motions. I lie
philofophers who are attached to this doCtrine of mov¬
ing forces, proceed to account for thofe prefling powers
or felicitations to motion which are obferved in the ac¬
celeration of falling bodies, the phenomena of magne-
tilm and ele&ricity, and others of the fame kind, \\heie
motion is induced on certain bodies which are in the
vicinity of other bodies, or as it is exprefled in common
language by the aCtion of other bodies at a diftance.
To fay that a magnet cannot aft on a piece of iion. at
a diftance, is to fay that it afts where it is not j which
is not lefs abfurd than to fay that it afts, when it is not.
Euler affumed it is an axiom, nihil moveturr niji a con~-
tiguo et nwto.
The methods propofed by thefe philofophers to pro¬
duce preffure, are lefs ingenious and not more fatisfac-
tory than that adduced by Euler which was mentioned
above} and indeed they do not feem to be very anxious
about the manner in which thefe motions are produced.
The phenomena of magnetilm are induced, or a piece
of iron is put in motion, when it is in the vicinity of a
magnet, by a ftream of fluid which iffues from one pole
of a magnet, paffes in a circle round the magnet, and
enters at the other pole. By this ftream of fluid the
iron is impelled, and brought to arrange itfelf in cer¬
tain determined pofitions. In the fame way all bodies-
are impelled in lines perpendicular to the furface of the
earth by a ftream of fluid wrhich is in continual motion
towards its centre. In the fame way fimilar phenome¬
na are accounted for, and thus thefe motions are redu¬
ced to Ample cafes of impulfion. But to fay. nothing
worfe of this doftrine, it is not very compatible with
the diftates of common fenfe. It proceeds on the fup-
pofition that fomething afts which we do not fee j and
of the exiftence of which there is not the fmalleit
proof.
96. Preffure, according to the opinion of others, is or p^fftire,
the only moving force in nature } but it is that kind of
preffure wdiich has been termed felicitation, not what
arifes from the mutual contaft of folid bodies. Gravi¬
tation is an inftance of the kind of preffure here allud¬
ed to. It is affirmed by thefe philofophers, that there
is no fuch thing as contaft on the inftantaneous commu¬
nication of motion by the real collifion of bodies.. It
is faid that the particles of folid bodies exert very ftrong
repulfions
4®o D Y N A
°'”;’"ne repuli’iims to a fmall diftance ; and when they are
^ y ' brought by any motion fufficiently near to another
ooay, they exert a repulfive force, and are equally re¬
pelled by this body. Motion is thus produced in the
one body, while it is diminilhed in the other. It is
then Ihown by fcmpuloufly confidering the Hate of the
bodies while the onp advances, and the other retires, in
what way they attain a common velocity, the quantity
of motion before coliifion remaining the fame, and the
one body gaining exaftly as much as the other lofes.
Cafes aifo are adduced, of fuch mutual adlion between
bodies, where it is obvious they have never come into
contaft 5 but where the refult is exactly the fame as
" hen the motion feemed to be mftantaneoufly changed.
-And hence it is concluded that there is no fuch thing
as inllantaneous communication, or transfufion of mo¬
tion by contact m colli/ion or xmpulfe. .All moving
forces according to thefe philofophers, are of that kind
which have been named felicitations > luch as gravi
ty is.
afnlechanifc • 97‘ DIfferent.names W been given to the exer-
cal forces tlons_°f mechanical forces, according to the reference
named from ** made to the refult. In wreltling when my an-
their refult. tagonilt exerts his ftrength to prevent being thrown
down, and I am fenfible of his exertion, I thus difeover
that he refills. But if I oppofe him only to prevent
him throwing me, I am faid to refill.. If I Itrike or
endeavour to throw him, I am faid to aft. The fame
diltinftion is applied to the exertion of mechanical
powers. If, for inltance one body A change the mo¬
tion of another body B, the change in the motion of
B may be conlidered either as the indication and mea-
fure of the power of A in producing motion, or as the
indication and meafure of the reliltance made by A in
being brought to reft, or having any change induced
on its motion. I he diftinftion which is here made is
not in the thing itfelf, but exifts only in the reference
which we are difpofed to make of its effeft, from other
conliderations. If a change of motion take place when
one of the powers ceafes to be exerted, it is conceived
that this power has relifted. But this language is me¬
taphorical. Reliftance, effort, endeavour, are all words
which exprefs motion that relate to fentient beings.
There is perhaps no word preferable to the word reac¬
tion y to exprefs the mutual force wdiich is obferved in
all the operations of nature which have been fuccefsful-
ly inveftigated.
Suppoled to p8. A difficulty has been ftarted with regard to the
a tt raft ion' °P^on thofe wrho affirm that all mechanical pheno-
and repul- mena are dependent on attrafting and repelling forces ;
(ion. becaufe it is here fuppofed that bodies aft on each other
at a diftance, and however Imall this diftance may be,
this is conceived to be abfurd. It may howrever be
obferved, that the mutual approaches or receffes of bo¬
dies may be aferibed to tendencies to, or from each
other. Without thinking of any intermediate connec¬
tion between the iron and the magnet, we conceive the
iron to be affefted by the magnet •, and if this be con¬
ceivable, it is not abfurd. Our knowledge of the e£-
fence or nature of matter is not fuch as to render this
tendency of the iron to the magnet impofiible. We do
not indeed fee intuitively why the iron fhould approach
to the magnet ; but this is by no means fufficient to
pronounce it impoffible or inconfiftent with the nature
of matter. To fuppofe therefore in the produftion of
3
M ICS. m II,
motion, the impulfe of an inviftble fluid, of which we Of Moving
know not any thing, and of whofe exiftence there is no Forces.
evidence, is a ralh and unwarrantable affumption. But '• *
farther, if it be true that bodies do not come into con-
taft, even when one ball ftrikes another, and drives it
before it, the fuppofition of the exiftence of this invi-
fible fluid will not aflift us in folving the difficulty j for
the fame difficulty would occur in the aftion of any one
particle of the fluid in the body. At any rate the pro¬
duftion of motion without any obferved contaft, is more
familiar to us than the produftion of motion by one
body afting on another by impulfion. Every cafe of
gravitation is an inftance of this.
99. In thofe cafes wffiere the exertions of any media-Attraftlon
nical power are obferved to be always direfted toward and rePuU
any body, that body is faid to attract. Thus a boat is
attrafted toward a man when he pulls it toward him13
by means of a rope. This is a cafe of pure attraftion.
But when the other body always moves off, the body
exhibiting this phenomenon is faid to repel; and it is a
cafe of pure repulfioti when a perfon pufhes any body
from him. A^d becaufe there is a refemblance to the
refults of real attraftion and repulfion, the fame terms
are employed to exprefs the mechanical phenomena of
nature. But that our conceptions may not be embarraf-
fed or rendered obfeure by the ufe of fuch metaphorical
expreflions, it is requilite to be careful not to allow
thefe wmrds to fuggeft to us any opinion about the man¬
ner in which mechanical forces produce their effefts.
If the opinion which is held of the exiftence of an in-
vifible fluid on wdiich mechanical aftion depends be
w'ell founded, it is obvious that there can be neither
attraftion nor repulfion in the univerfe.
100. Forces are conceived as meafurable quantities. Forces
Thus we conceive one man to poffefs double the ftrength rneafurable
of another man, wffien we obferve that he can refift the (lliantlties»
combined efforts of two others. It is in this wray that
animal force is conceived as a quantity made up of its
own parts and meafured by them. This however feems
not to be a very accurate conception. Our conception
of one ftrain being added to another is obfeure, aT
though w'e have a diftinft notion of their being com¬
bined. There are no words to exprefs the difference of
thefe two notions in our minds ; but we think that the
fame difference is perceived by others. We have a
clear conception of the addition of two lines or two
minutes ; but our notions of two forces combined are
indiftinft j although it cannot be affirmed that two
equal forces are not double of one of them. They
are meafured by the effefts which they are known to
produce.
101. In the fame way mechanical forces are conceiv-and fuch as
ed as meafurable by their effefts, and thus become the aie media-
fubjefts of mathematical difeuffion. We fpeak of theniCal*
proportions of magnetifm, eleftricity See. and even of
the proportion of gravity to magnetifm. Thefe hotv-
ever, confidered in themfelves, are quite diflimilar, and
do not admit of any proportion j but feme of their ef¬
fefts are meafurable, and thefe affumed meafures being
quantities of the fame kind are fufceptible of compari-
fon. The acceleration of motion in a falling body, is
one of the effefts of gravity j magnetifm accelerates
the motion of a piece of iron j and thefe two accelera¬
tions may be compared together. But becaufe none of
the meafurable effefts of magnetifm with which we are
acquainted
Part II, D Y N A
Of Moving acquainted, are of the fame kind with any of th_
Forces, effects of heat, magnetifm and heat are not iuiceptible
' v t 1 of comparifon. . _ ,
Lompanfon wheri it is faid that the gravitation of the moon is
Teds of ‘ the 3600th part of the gravitation at the fea-lhore, it is
gravity. meant that the fall of a Hone in a fecond is 3600 times
greater than the fall of the moon in the fame time.
But to exprefs the proportion of the tendency of gravi¬
tation more purely, if a ftone hung on the fpring of a
fteelyard, draw out the rod of the lleelyard to the mark
3600, the fame ftone carried up to the diftance of tlm
moon will draw it out only to the mark one. And it
the ftone at the fea-fhore draw out the rod to any mark,
it will require 3600 fuch ftones to draw the rod out
to the fame mark at the diftance of the moon. Norv,
it is not in confequence of an immediate perception of
the proportion of gravitation at the moon to that at the
furface of the earth that fuch an affertion is made. It
is becaufe thefe motions being confidered as its effedfts
in fuch fttuations, and being magnitudes of the fame
kind, are fufceptible of companion, and have a pro¬
portion svhich can be determined by obfervation. And
although the proportions of the caufes or forces are
fpoken of, yet it is only the proportions of the effects
which come under contemplation.
Meafures 102. In order that thefe affumed meafures may be
mult be the accurate, they muft be always connected with the
kind and
degree.
Dynamics
a demon-
ftrative
fcience.
Forces dif¬
fer in di¬
rection.
magnitudes which they are employed to meafure 5 arid
the connedtion muft be of that kind, that the degrees
of the one muft change in the fame manner with the
degrees of the other. The fame thing muft alfo be
known of the meafure which is employed ; the precife
and conftant relation muft be feen. But how is^ this to
be accomplifhed ? Force as a feparate exiftence is not a
perceptible objedt. We do not perceive its proportions,
fo as to be able to afeertain that they are the fame with
the proportions of the meafures. On the contrary, the
very exiftence of this force is inferred from obfervation
of the acceleration, and its degree is alfo an inference
from the obferved extent or magnitude of the accelera¬
tion. The meafures wrhich are thus allumed are there¬
fore neceffarily connected with the magnitudes, and
their proportions are the fame } the one is an inference
from the other both in kind and degree.
103. It now appears that this fubjedt is fufceptible
of mathematical inveftigation. After having felefted
our meafures, and obferving certain mathematical re¬
lations of thofe meafures, every inference deduced from
the mathematical relations of the proportions of thofe
reprefentations is true of the proportions ot tne motions,
and therefore it is alio true of the proportions of the
forces. Thus then Dynamics may be reckoned a de-
monftrative fcience.
104. Moving forces are confidered as differing alfo
in kind, that is, in diredtion. The diredtion of the ob¬
ferved change ot motion is aftigned to the force } which
is not only the indication, but alfo the meafure of the
changing force. I. his force is called an accelerating,
retarding, or deflecting force, according as it is obier-
ved, that the motion is accelerated, retarded, or de-
fledted. And from thefe terms it muff appear, that we
have no knowledge of the forces different from our
knowledge of the effeas. They are either deferiptive
of the effeas, or they have a reference to the fubftan-
ecs in which the forces are fuppofed to be inherent.
Vol. VII. Part II.
M 1 C S. , „ 481
Thus of the firft kind are the terms accelerating, altrac- °f
live, or repuljive forces ; of the lecond, are the terms , '^
magnetifm, ele&riaty, &c.
Of the Laws of Motion.
10 Such then being our notions of mechanical
forces', of the caufes of the produaion of motion and
its changes, there are certain refults, which by the
conftitution of the human mind, neceffarily arile from
the relations of thefe ideas. Thefe refults are laws of
human judgment, independent of all experience of ex¬
ternal nature. Some of thefe laws may be intuitive,
prefenting themfelves to the mind as foon as the ideas
which they involve are prefented to it. 1 hefe may be
called axioms. Others may be as neceffary relults
from the relations of tbeie notions, are lels obvious,
and may require a procefs of reafoning to eftablifti their
truth.
Of thefe laws there are three, which were firft di *
ftindfly propofed by Sir Ifaac Newton. Thefe may be
confidered as the firft principles of all difeuflions in me¬
chanical philofophy, give a fufheient foundation ior all
the doarines of Dynamics, and to thefe principles we
may refer for the elucidation of all the mechanical phe¬
nomena of nature.
Firjl Law of Motion.
106. Every body continues in ajlate of rejl, or of
uniform recidineal motion, unlefs it is affected by fame
mechanical force.
On the truth of this propofition the whole of mecha- Importance
nical philofophy chiefly depends. But with regard toof^Pr0-.
its truth and the foundation on which it refts, the opi- f5
nions of philofophers are very different. In general thefe
opinions are obfeure and unfatisfaaory 3 and, as is ufttal,
they influence the difeuflions of thofe who hold them in
all their inveffigations.
107. It is not only the popular opinion that a ftateRefl fup-
of reft is the natural ftate of body, and that motion is
fomething foreign to it, but the fame opinion has been con[1;tioll
fupported by many philofophers. They allowT that 0f body,
matter unlefs it is acted on by fome moving force will
remain at reft 3 and nothing feems neceflary for matter
to remain where it is, but its continuing to exift. . But
the cafe is widely different, according to thefe philofo¬
phers, with refpedt to matter in motion. I'or here the
relations of the body to other things are continually
changing 3 and as there is the continual producHon of
an effecl, the continual agency of a changing caufe is
neceffary. This metaphyfical argument, it is faid, is
fully confirmed by the moft familiar obfervation. All
motions, whatever may have been their violence, termi¬
nate in reft, and for their continuance the continual
exertion of fome force is neceffary.
108. It is affirmed by thefe philofophers, that the Continual
continual action of the moving caufe is effentially requi-^J1™ olc
ftte for the duration of the motion. But their opinions ce^-ai.yejn
of the nature of this caufe are not uniform. Accor- moti0n,
ding to fome, all the motions in the univerfe are pro¬
duced and continued by the diredl agency of the Deity
himfelf. By others all the motions and changes of
every particle of matter are aferibed to a fort of mind
which is inherent in it. I his is called an elemental
mind.. It is the fame as the q>vvi<; and the Hyvp of
Ariftotle. Every thing, according to thefe philolo-
3 P phers,
48^ t) Y N A
Of Moving phct% v/mcii MoVis, is snb4, and every thiftg %vhkh
, Forc('s- , is moved is body. But this elemental'mind’is only
known and chara&erized by the tffedls which are a-
i’enbed to its a£i;on 5 and thefe are obferved in the mo¬
tions or changes which are produced. Thefe, we learn from
uniform experience, are regulated by laws equally precife
wth the law s of mathematical truth. But there is nothing
which indicates any thing like intention or purpofe ;
none of the marks or charafters by which mind was
brought fMl into view. They refemble the efFefts pro¬
duced by the exertions of corporeal force ; and hence
the word force has been applied to exprefs the caufes of
motion.
mabfolute 1 A ^ate red, it has been fuppofed, is the natu-
iek. r.a^ ^ate matter> ^ut h does not appear that the con¬
tinued action of feme caufe is neceflary for continuing
matter in motion. Experience gives us no authority
for fuppofmg that the natural condition of matter is a
flate of reft. It cannot be affirmed of any body what¬
ever that it has ever been feen in abfolute reft. All
the parts of the planetary fyftem are in motion 5 and
even the fun himfelf with his attendant planets is car¬
ried in a certain direction with a great velocity. There
is no tmqueftionable evidence that any of the ftars are
absolutely fixed ; and many of them, it has been afeer-
tamed by obiervation, are in motion. Reft, therefore
being fo rare a condition of matter, no experience which
we have, fupports the notion that this is its natural con¬
dition. This opinion feems to be derived from our owm
experiments on matter. To continue the motion of a
body, we find that the continued aiftion of fome mov¬
ing force is neceftary, otherwife the motion becomes
gradually flower, and at laft terminates in reft. Since
then we fee that our own exertions are conftantly necef-
fary in the produftion of motion, and efpecially in thofe
cafes where we are interefted 5 we are thus induced to
alcribe to matter fomething that is naturally quiefeent
and inert,, and even fomething that is fluggilh and
averfe from motion. But this is an erroneous concep¬
tion, which is fuggefted to our thoughts from the im¬
perfection of language. We aferibe animation to mat¬
ter to give it motion, and endow it with a kind of
moral character in order to explain the phenomena of
motion.
Matter has . no. Butmoreaccurateandmoreextendedobferva-
aptitiic e to tj°^ jea(js us to that matter has no peculiar
aptitude to a ftate of reft. Every obierved retardation
has a diftinft reference to external circumftances.
Wherever there is a diminution of motion, it is invaria¬
bly accompanied by the removal of obftacles j as in the
cafe when a ball moves through fand, or air, or water.
The diminution of motion is alfo owing to oppofite mo¬
tions which are deftroyed. And it is found that the
more thefe obftacles are kept out of the way, the lefs is
the diminution of motion. The vibration of a pendu¬
lum in water foon ceafes ; it continues longer in air ;
and much longer in the exhaufted receiver. The con-
clufion then from thefe obfervations is, that if all ob¬
ftacles could be completely removed, motion would
continue for ever. This conclufion is Itrongly fupport-
ed by the motions of the heavenly bodies. Thefe mo¬
tions, fo far as we know, are retarded by no obftacles 5
and accordingly they have been obferved to retain
them without perceptible diminution for thoufands of
years.
M 1 c S. ' Part II.
Hi. The inactivity of matter has been denied by Of Moving
other philofophers. According to them it is effentialiy Forces. "
active, and continually undergoing changes in its con- 'y~ (
dition.. . Some traces of this doctrine are to be found in de“
the writings of fome of the ancient philofophers} but it othersf
was reduced to a fyftematic form by Leibnitz. According
to. this philofopher, every particle of matter is endowed
with a principle of individuality. This he calls a mo-
na'i, which is fuppofed to have a kind of perception of
its place in the univerfe, and of its relation to all other
parts of the univerfe. This monad too is fuppofed to
act on the particle of matter in the fame way as the
foul a&s on the body. The motion of the material
particle is modified by the monad, and thus are produ¬
ced, according however to unalterable laws, all the ob¬
ferved modifications of motion. And thus matter, or
the particles of matter, are continually active and conti¬
nually changing their fituation. No information in
any way ufeful can be obtained from this fanciful hy-
pothefis. It is not unlike the fyftem of elemental
minds. And ftiould its exiitence be admitted, it would
not any more than the actions of animals invalidate the
general proportion which is confidered as the funda¬
mental law of motion. The powers of the monads or
of the elemental minds are fuppofed to be the caufes of
all the changes ; but the particle of matter itfelf is fub-
je6t to the law, and any change of motion which it ex¬
hibits is aferibed to the exertion of the monad.
11 2. By another fet of philofophers, this law of mo- This law
tion is deduced from the want of a determining caufe deduced
At the head of this fett is Sir Ifaac Newton, who main’from th,e
tains the doctrine affirmed in the propofition. But thefe JeSmiJ*
philofophers are not uniform in their opinion of the foun-ning caufe,
dation on which it refts. It is afleited by fome that it is a
kind of neceflary truth which arifes from the nature of the
thing. If, for inftance,.a body in a ftate of reft, and if
it be aflerted that it will not remain at reft, it muft
move m fome dire&ion ; and if it be in motion in any
direition, and with any velocity, and do not continue
its equable, re&ilineal motion, it muft be either accele¬
rated or retarded 5 it muft either turn to one fide, or to
fome other fide. The event, whatever it be, is indivi¬
dual and determinate ; but no caufe which can deter¬
mine it being fuppofed, the determination cannot take
place, and no change with refpeft to motion will hap¬
pen in the condition of the body. It will either re¬
main at reft, or perfevere in its reclilineal and equable
motion. But to this argument of fufficient reafon, as
it has been called, confiderable objections may be made^
In the immenfity and perfeCt uniformity of time and
fpace, there is no determining caufe why the vifible
univerfe Ihould exift in one place rather than in another,
or at this time rather than at another. It is effentially ne¬
ceflary that there ftiould be a caufe of determination j
for a determination may be without a caufe, as well as
a motion without a caufe.
113. Other philofophers deduce this law of motion and from
from experience. They confider it merely as an expe-exPeriencc»
rimental truth, of the univerfality of which there are
innumerable proofs. When a ftone is thrown from the
hand, it is prefled forward, and when the hand has the
greateft velocity that we can give it, the ftone is let go,
and it continues in that ftate of motion which it gradu¬
ally acquired along with the hand. A ftone may be
thrown much farther by means of a fling, becaufe with
a
1'art H.
D Y N A
motion
Of Moving a very moderate motion of the hand, the ftone being
Forces. whirled round acquires a very great velocity, and when
v "it is let go, it continues its rapid motion. We have a
limilar illuftration in the cafe of an arrow {hot from a
bow. The Itring which prelTes hard on the notch of
the arrow carries it forward with an accelerated motion
as it becomes a ftraight line by the unbending of the
bow $ and there being nothing to check the arrow, it
flies off. In thefe Ample cafes of perfeverance in a hate
of motion the procedure of nature is eafily traced j it is
in cafes cf Perce^ve^ ahnoft intuitively. In many other phenome¬
na it is not lels diitindt, although fomewhat more com¬
plicated. A man can {land on the faddle of a horfe at
a gallop, and ftep from it to the back of another horfe
that gallops along with him at the fame rate j and this
he feenfs do with the fame eaie as if the horfes were
{landing Hill. The man is carried along with the fame
velocity as the horfe which gallops under him, and he
retains the fame velocity while he ileps from the back
of one horfe to that of the other. But if the horfe to
which he fteps were Handing Hill, he would fly over his
head, becaufe he is carried forward with the velocity of
the galloping horfe ; or if he Hepped from the back of
a horfe Handing Hill to that of one at a gallop, he would
be left behind 3 becaufe he has not acquired the veloci¬
ty of the galloping horfe* In the fame way, a man toffes
oranges from one hand to the other while he is carried
forward with the motion of a horfe at a gallop, or while
he fwings on the flack-wire. In both cafes the oranges
have the fame motion as the man, and while they are in
the air are moving forward with the fame velocity, fo
that they drop into the hand at a confiderable ditlance
from the place in which they were thrown from the
other hand. While a Ihip fails forward with a rapid
motion a ball dropped from the mafl head falls at the
foot of the mafl ; for it retains the motion which it had
previous to its being dropped, and follows the malt du¬
ring the whole time of its fall.
114. Familiar inflances may alfo be given of a body
in 3 Hate of refl. A veflel filled with water drawn
fuddenly along tbe floor, leaves the water behind,
which is dafhed over the pofterior flde of the veffel; and
when a boat or coach is fuddenly dragged forward, the
perfons in it find themielves Hrike againfl the hinder
part of the carriage or boat ; or rather it fhould be faid
the carriage flrikes on them, for it fooner acquires mo¬
tion from the adlion of the force applied. A ball dif-
charged from a cannon will pafs through a w’all and
move onward ; but the wall remains behind.
115. Common experience is perhaps infufficient for
efiablifliing the truth of this fundamental propofition.
It mufl be granted, that we have never feen a body ei¬
ther at refl, or in uniform rectilineal motion ; yet this
feems neceffary before it can be faid that the propofition
is experimentally eftabliflved. What is fuppofed in our
experiments to be putting a body, formerly at refl, into
motion, is in faft only producing a change of a very
rapid motion—a motion not lefs than 90,000 feet per
fecond.
Other pi oof 11^- For the purpofe of obtaining fuch experimental
neceflary. proof of the truth of this propofition, it w ill be neceflary
to refort to other obfervations. The relative motions
of bodies, which are the differences of their abfolute mo¬
tions, only can be meafured. We cannot meafure their
abfolute motions. If then it can be fliovvn by experi-
and of reft.
But com¬
mon expe¬
rience in¬
fufficient.
M I C $. 483
ment that bodies have equal tendencies to refifl the Of Moving
augmentation and diminution of their relative motions, 1 orces' ,
they thus have equal tendencies to refifl the augmenta- v "*
tion or diminution of their abfolute motions.
Let A and B two bodies be put into fuch a fltuation,
that they cannot perfevere in their relative motions.
The change which we obferve produced on A is the ef-
fe£i and meafure of the tendency of B to perfevere in
its former ftate. From the proportion of thefe changes
therefore we derive the proportion of their tendencies
to remain in their former condition. This will be il-
luflrated by the following experiment which fhould be
made at noon.
117. Let the body moving at the rate of three feet
per fecond to the weftward, ftrike the equal body B
which is apparently at reft. Different cafes of the re-
fults of the changes thus produced may be fuppofed.
1 ft. Let A impel B forward without having its own
velocity at all diminifhed. From this refult it appears
that B fhows no tendency to maintain its motion un¬
changed, but that A retains its motion without dimi¬
nution.
2d. Suppofe that A flops, and that B remains at refl.
Tins cafe {hows that A does not rciift a diminution of
motion, and that the motion of B is not changed.
3d. Let it be fuppofed that both move weftward at
the rate of one foot per fecond. There is in this cafe a
diminution of the velocity in A, equal to two feet per
fecond. This then is to be confidered as the efFe6i and
meafore of the tendency of B to maintain its velocity
unaugmented. B has received an augmentation of one
foot per fecond in its velocity. From this change it
appears that the tendency is but half of the former $
and the refult {flows that the refiftance to a diminution
of velocity is only equal to one half of the refiflance to
augmentation 3 and perhaps equal only to one quarter,
lince the change on B has effected a double change
on A.
4th. Let it be fuppofed that both bodies move for¬
ward with the velocity of one and a half feet per le-
cond. In this cafe it is obvious that the tendencies of
the two bodies to maintain their Hates unchanged are
equal.
5th, But fuppofe that A~ 2B, and that the velocity
of both after collifion is equal to two feet per feccnd <
The body B has then received an addition of two feet
per fecond to its former velocity 3 and this is the effect
and meafure of the whole tendency of A to preferve
its motion undiminilhed. One half of this change on
B meafures the perfevering tendency of one half of A}
but it is fuppofed that A which formerly moved with the
the apparent or relative velocity three, now moves with
the velocity two, and thus has loft the velocity of one
foot per fecond. Therefore each half of A has loft tins
velocity 3 and the whole lofs of motion is two. This
then is the meafure of the tendency of B to maintain
its former ftate unaugmented ; and it is the fame with
the meafure of the tendency of A to preferve its former ^
ftate undiminiihed. From fuch a reiult therefore the
conclufton would be that bodies have equal tendencies
to maintain their former ftates of motion unaugmented
and undimini Hied.
The fuppofitions made above in the 4th and 5th cafes
are the refult of all the experiments xvhich have been
made 3 and in all the changes of motion which are
3 P 2 produced
Exiftence
of forces
inferences
from mo¬
tion.
D Y N A
Of Moving produced by tlie mutual action of bodies on impulfion,
Forces- _ this is the regulating law. To this there is no excep-
v ‘ tion. And thus it appears that there exifts in bodies
no preferable tendency to reft. No fa£t can be addu¬
ced which fhould lead us to fuppofe that a motion hav¬
ing once begun ftiould fuffer any diminution without
the intervening atlion of fome changing caufe.
This proof x j g. jt however, be obferved that this is a very
imperfect. jmperfe(ct way Gf eftablilhing the firft law of motion.
It is inapplicable to thofe cafes where experiment can¬
not be made j and at beft it is fubjeff to all the inac¬
curacy of the beft managed experiments. If this pro-
polition be examined by means of the general princi¬
ples which have been adopted in the article PHILOSO¬
PHY, (which fee) an accurate decifion of this queftion
may be given. Thefe principles, which are the founda¬
tion of all cur knowdedge, lhewr that this propofition is
an axiom or intuitive confequence of the relations of
thofe ideas which we have of motion, of its changes,
and of their caufes.
119. Powers or forces, it has been Ihewm, are not
the immediate objefts of our perceptions. Their exif¬
tence, kind, and degree, are inferences from the motions
wdiich we obferve. And hence it follows, that when
no change of motion is obferved, no fuch inference is
made $ no force or powrer is fuppofed to act. But
when any change of motion is obferved, the inference is
made} a power or force is fuppofed to have a£ted.
By a ftmilar conclufion, it is faid, that when no change
of motion is fuppofed, no force is thought of or fuppo¬
fed 5 and whenever a change of motion is fuppofed, it
always implies a changing force. On the other hand,
when the adlion of a changing force is fuppofed, the
change of motion is alfo fuppofed} the adlion of this
force and the change of motion being the fame thing.
The mind does not admit the idea of the action, with¬
out at the fame time thinking of the indication of the
action, and this indication is the change of motion.
And in the fame way, when we do not think of the
changing force, or do not fuppofe the aftion of a
changing force, wre fuppofe, although it be not expref-
fed in terms, that there is no indication of this chan¬
ging force j that there is no change. If, therefore, it
be fuppofed that no mechanical force a£ts on a body,
we fuppofe in fa<ft that the body remains in its former
condition with refpedl to motion. And if it be fuppo¬
fed that nothing accelerates or retards, or deflefts the
motion, it is conceived as neither accelerated nor retarded,
nor deflefted. Hence it follows, that we fuppofe the bo¬
dy to continue in its former ftate of reft or motion, unlefs
we fuppofe that it is changed by fome mechanical force.
This law I 20. This propofition then does not depend on the
a neceflary properties of body as a matter of experience or contin-
truth. gency. It is to us a neceffary truth. It is not fo mucli
any circumftances with regard to body that are expref-
fed in the propofition, as the operations of the mind in
confidering thefe circumftances. The truth of the pro¬
pofition will not be invalidated by taking into view,
that it may be effential to move in fome particular di-
reftion •, that it may be effential to body to ftop when
the moving caufe ceafes to aft } or gradually to dimi-
niftv its motion, and at laft to come to reft. The circum¬
ftances in the nature of body which render thofe modifica¬
tions effentially neceffary, are the caufes of thofe modifica¬
tions j and they are to be confidered as changing forces.
M I C S. Part II.
If we ftiould fuppofe that body of its own nature is Of Moving
capable of producing a change in its condition, this , Fo"ces- ,
change muft be effecled according to fome law which y
characterizes the nature of body. But the knowledge
of this law can be obtained only by obfervmg the de¬
viations from uniform reCtilineal motion. It then be¬
comes indifferent whether external caufes operate thole
changes, or they depend on the nature of the thing j
for in confidering the various motions of bodies, we mult
firft confider the nature of matter as one of its me¬
chanical affeftions which operates in every inttance *,
and this brings us back to the law contained in the pro¬
pofition. This is rendered more certain by reflecting,
that the external caufes, fuch for initance are gravity
and magnetifm, which are acknowledged to operate
changes of motion, are not lefs unknown To us than
this effential property of matter. They are,'like it,,
only inferences from the phenomena.
I 21. Many philofophers, among which number may Inadequate
be included Newton himfelf, have introduced modes ofnemomfug-
expreflion, which fuggeft inadequate notions, and luch frfac^.(ira^e
as are incompatible with the doCtrine of the propofition •, eXpleflions.
for although they allow that reft is the natural condi¬
tion of body, and that force is neceffary for the con¬
tinuation of motion, yet they fpeak of a power 01 force
refiding in a moving body by which it perfeveres in its
motion. This has been called the vis infita, or the in- *
herent force of a moving body. Now if the motion
be fuppofed to be continued in confequence of a force,
that force muft be fuppofed to be exerted, and it is
fuppofed that if it were not exerted the motion would
ceafe. The propofition, therefore, mull be falfe. To
obviate this objeClion it is indeed fometimes faid, that
the body continues in uniform reCtilineal motion, un¬
lefs it is aCted on by fome external caufe. I his mode
of expreflion, however, fubjeCts us to the impropriety
of afferting that gravity, eleClricity, and other mecha¬
nical forces, are external to the bodies on which they
are fuppofed to aft and to put in motion. Every thing
which produces a change of motion is very properly
called a force } and when a change of motion is ob¬
ferved, the aftion of fuch a force is very properly in¬
ferred. But to give the fame name to wrhat has not
this property of producing a change, and to infer the
aftion of a force when no change is oblerved, is not a
very accurate or confiftent expreflion. This error has
arifen from the ufe of analogical language in philofo-
phical difeuftions.
I 22. But motion is not, as philofophers have ima- Motion not
gined, the continual produftion off an effeft. We can 1 continued
conceive there is fuch a thing as a moving caufe, to
which the name of force has been given. This pro- ^
duces motion, and the charafter of motion in body,
which is a continual change of place. Motion is the
effeft of an aftion •, and previous to the commence¬
ment of the motion, this aftion is equally incomplete as
it is the minute after. The immediate effeft of a moving
force is a determination to motion, which if not ob-
ftrufted by fome caufe would go on for ever. In this
determination only the condition of the body differs
from a ftate of reft. Motion then is a condition or
mode of exiftence, which no more requires the conti¬
nued agency of the moving caufe than colour or figure.
Some mechanical caufe is required to change this con¬
dition into the ftate or condition of reft. When a
moving
D Y N A
OI Moving moving body is bvougbt to^re^, ^fomo C A
Forces, fation of motion never faiib t i i
  V ' caT is no lefs neceffary to flop the motion of body
than it is to produce it. Now this .caufe ®h;'
refide in the body or be external to it. If it relide in
he body, then it poff^s a felf-determimng power or
force, by which it may be able to hop its own motion
, “ It1 minT^tL of the fubjeft the opinion
of atree refifing in a moving body by mo-
herent ti0n is continued muft be given up } and the remarka
force- ble difference between a body m a ftate of motion an-
a ftate of reft muft be explained on other
Motion, it cannot be doubted, is neceffary m the im¬
pelling body to permit the forces which are inherent m
one of both bodies to continue the preffure long enoug i
for the produftion of fenfible motion. But whedier
bodies be in the condition of motion or reft, theie
forces are inherent in them. It we reded on t re m -
tions that are involved in the general conception of one
body beinf impelled and put m motion by another, we
(hall fee that there is nothing individual transferred
from the one to the other. Before collihon took place
the determination to motion exifted only m the impe-
ling body. After collifion, both bodies poffefled this
condition or determination. But we have no concep.
tion, we can form no notion of the thing transferred
i 24. An expreffion not lefs vague _ and indefinite is
f"'” A’^.alfo very common among mechanical philosophers.
SmtcYerm. This is the phrafe inertia, or vis inertia. Ihis expre-
fion, which was introduced by Kepler, leems to a
been generally employed by him as well as by Newton
to exprefs the fad of the perfeverance of body m a
ftate of motion or reft. Sometimes, however it has
been employed by thefe philofophers to exprefs fome-
thing like indifference to motion or reft;, and this is
fuppofed to be manifefted by body requiring the fame
quantity of force to make an augmentation of its mo¬
tion, as is neceffary to produce an equal diminution oi
it. To fuppofe refiftance from a body at reft leems to
be in dired contradidion to the common ule oi the
word force; and yet this exprelfion vis inert ice is very
common. It is not lefs abfurd to fay that a body
remains in the condition of reft by the exertion of a
vis inert ice, than to affirm that it maintains itielf m a
ftate of motion by the exertion of an inherent force.
Such expreffions, which are metaphorical, ftiould be
carefully avoided, becaufe they are apt to lead to mii-
conception of the procedure of nature.
n ra r. 1 2s. In the phenomena of motion the force employ-
of^matter*a ed always produces its complete effed. No refiftance
mificoncep- whatever is obferved. When one man throws down
tion. another, and he finds that no more force has-been re¬
quired than to throw down a fimilar and equal mats
of inanimate matter, he concludes that no refiftance
has been made-, but if more force be neceflary, tire con-
clulion is that refiftance has been made. When there¬
fore the' exerted force produces its full efted, there is
nofuch thing as refiftance properly fo called. It is
therefore mifconceiving the mode m which mechanical
forces operate in the collifion of bodies, to fay that
there is any refiftance. For there is no more m thefe
cafes than in other natural changes of condition. It
may be obferved, that thefe terms inherent force and
inertia, may be employed for the purpofe of abbrevia-
M ICS. 4° 5
ting language, pruvided they aft ufed only for
5 either the fimple fad of perfevermg m the former ^  
ftafe or the neceffity of a determinate force to produce
a change on that ftate, being careful to avoid all thoug
°f Thus it appears that deviations from uniform Deviations
.2 ■ of the exiftence and [r°m um-
126. inus it appears unu. -r. andfr°m un5'
motions are the only indications o . form mo-
agency of mechanical forces. This indication is ft yticn indi.
ply change of place } and it can only indicate what is cations of
very fimple, fomething competent to the produdion offorce.
theyobfePrved motion. The fame thing is indicated by
two fimilar changes of motion. A compafs needle m
a ftate of reft, can be moved fome degrees by means of
the finger, a magnet, an eledrified body, or by the un¬
bending of a fpring, &c. in all which cafes the indi¬
cation is precifelythe fame j and ^erefore the thing
indicated muft alfo be the fame, ihis is the mtenfity
and diredion of fome moving power. Ihe circum-
ftances of refemblance by which the affedions of mat¬
ter are to be charaderized are impulfiveneis intenfity,
and diredion. This leads us to conftder the fecond
law of motion.
Second Law of Motion.
Every change of motion is proportional to the force
impreffed, and it is made in the direction of that force. .
I2V This law of motion alfo may almoft be conii-Is an iden-
dered as an identical propofition. It is eFuvalfnt
faying that the changing force is to be meafured by theP
change produced, and the diredicn of this force is the
diredion of the change. Confidermg the force only
in the fenfe of its being the caufe of motion and with¬
drawing the attention from the manner or form oi its
exertion, there can be no doubt of this. In whatever
way a body is put in motion, whether by the expanftve
force of the air, by the unbending of a fpring or by
any fimilar preffure, when it moves oil m the iame di¬
redion, and with the fame velocity, the force or the
exertion of the force is confidered as the fame. Even
when it is put in motion by inftantaneous percuthon
from a fmart ftroke, although in this cafe the manner
of the effed being produced is effentially different from
the other cafes, we cannot conceive the propelling
force, as fuch, but as precifely one and the fame. 1 he
expreffion of this law of motion by Newton is equi¬
valent to faying, “ that the changes of motion are ta-
ken as the meafures of the changing forces, and the
diredion of the change is taken as the indication oi
the diredion of the forces j for it cannot be laid that but not de-
it is a deduffion front the »ckuo«ledged p„nctpe that dated t™,
effeds are proportional to their caufes. Ihis ,15t ,u, of the
not affirmed from the proportion of the forces and _theforce3.
proportion of the changes, and that thefe proportions
are the fame, having been obferved} and that tins
univerfally holds in nature. For forces are not objects
of obfervation, and we do not know their proportions.
In this way it would be eftabliffied as a phyftcal law, as
indeed it is fo in fad. But according to the definition
of the term, this does not eftabliffi it as a law of mo¬
tion ; or as a law of human thought, the remit oi the
relations of our ideas. Philofophers having attempted
to prove this as a matter of obfervation, have produced
great diverfity of opinion in the mode cn elhmatmg,
forces. A bullet, it is well known, which moves with
double velocity, penetrates four times as far. This is
confirmed
41,0 D Y N A
0SCSfn!fnea, o*® ficr‘ilar &a» i and to trenerjte this
S'f r 'i T 'hc 1"'llet’ " ^ been gobfoved by
pfei.ofophers four ttmes the force is expended, four times
ns much p„lvdcr required. This is the i„variabie”e!
rt‘ ’ f:"afm.Ca'cs of ‘Ins kind, it would appear that
the rauo of the forces employed has been very accu
t^yafcertamed. The conclufion themfore 7s, that
/dg, , ar<i,notr Pr0Portional to the velocities oro-
uced but to the fquarcs of the velocities. This is
Prong y confirmed by obferving that moving bodiel
Ir J6 for ln th‘s vay foportioo, and to
p .o ice effoas ,:, this propomon ; when, for inftance,
timeltdE;: ° 7 tW1Ce a$ grCa'’ they P—
1 fr I( this mode of eftimation be juft, it is irrecon,
th,eaw7oc77 ' “"•'‘’'r. of*°% "ho ^tnit that
Incompa¬
tible with
the velo- v-wl,,:culon oi tnoie, who admit that
being the velocity is proportional to the force impreifed, in
proportion- tj0-6 caies where no previous obfervation can be had of
fc “ethE ‘fXn0 f • f0rc'c’ ?nd °f !,S c,lua!ity to the ratio
V h r rOCltmi’r S,uch a cafe 18 the force of gravity,
which thefe philofophers always meafure by its acce-
eratmg power, Or the velocity generated in a given
?hr muft be granted 5 for there are cafes in
which the force can be meafured by the aftual preffure
SaJ1 trX Tchu\? fP™g fteelyard can be con
^ruded, the rod of which is divided by hanging on
mccefhveiy a number of perfectly equal weights. In
the different ftates of tenfion of the fpring, its elafti-
fity is proportional to the preffures of gravity which it
balances. If it be found, that at Quito in Peru a
weight will pull out the rod to the mSk 31 2, and that
the fame weight at Spitsbergen draws it out to ,13, it
xeems to be a fair inference to fay, that the preffure of
gravity at Quito is to its preffure at Spitzbergen as 212
to 3J3 5 and this is affirmed on the authority of effe&s
being proportional to their caufes. Such cafes, how¬
ever, are very rare j for it is feldom, that the whole of
a natural power, accurately meafured in fome other way
is employed in producing the obferved motion. Part of
it is generally otherwife expended, and therefore it fre¬
quently happens that the motions are not in the propor-
71* ** f“PP?W forces. And allowing that this
could be done with accuracy, it would only be the
proof of a general law or fad : but thefe philofophers
attempt to eftabliffi it as an abftract truth. ? ?
129. It feems to be confidered by Sir Ifaac Newton
only as a phyucal law. And in this fenfe good argu-
ar,e Wantm^ A ball which moves with a
double, triple, or quadruple velocity, generates by im-
paffe in another, a double, triple, or quadruple veloci¬
ty, or it generates the fame velocity in a double, triple
or quadruple quantity of matter, and lofmg at the fame*
time Similar proportions of its own velocity
mp:Z° rbOCileu’ havinSTeft^l quantities of motion,
meet.ng together, mutually ftop each other.
When two forces, which aft fimilarly during equal
times, pioduce equal velocities in a third bodv, they
Tdoubfe Cr dUring ^ W ,;me’ produce
. If.a PrftTur<i which ads for a fecond, produce a
certain velocity, a double preffure a cling during a fe-
cond, will produce in the fame body a double velo-
A force which is known to act equably, produces in
city
- t I C S. pa!t jj-
Xife maX incrraenl! °} tel0c:ty- Kl“tew' the
,/n th,e samples above adduced, the forces are ' 
of Z t0 iVn,tbe ^'me ProPortion with the change
of motion effeded by them in a fimilar way. 6
miffilf 1 f ^lldous difeoveries of Dr Hooke, about the Hooke',
Zt6 11 1 century, feemed to (hew, from adlfcoveries.
g-eat coLedion of fads, forces to be in a very different
proportion. In the produdion of motion it was found,
that four fprmgs equal in ftrength, and bent to the
fame degree generated only a double velocity in the
ball which they impelled : nine fprings generated only
a triple velocity, &c. In the extindion of motion, it
rvS nenet’ 3 b^U m°Ving with a double velocity,
wi J penetrate four times as deep into a uniformly re-
lifting mafs 5 and a triple velocity wift make it pene¬
trate nine times as far, &c. P
. *30* ^ hefe fads were brought forv/ard by Leibnitz .•
iealUnat°rt °f ^ °T pretfenfl0ns to the di{bovery of the of LeibnS
al mature and meafure of mechanical adion and force
which he laid had been hitherto totally miftaken. He’
a irmed, that the inherent force of a moving body was
in the proportion of the fquare of the velocity^ In
who hC TS fuPP°rted b7 John Bernoulli,
who adduced many fimple fads to confirm the relation
between the inherent force of a moving body and its
velocity. _ One of the ftrongeft arguments urged by
-Leibnitz is, that the inherent force of a moving body
Is to be eftimated by all that it is able to do before the
total extindion of its motion j and therefore when it
penetrates four times as far, it is to be confidered as
haying produced a quadruple effed. In this mode of
eftimation many things are gratuitoufly affumed, many
contradidions are incurred 5 and it is only becaufe
forces are aiiumed as proportional to the velocities which
hey generate, that thefe feds come to be proportional
to the fquares of tne fame velocities. When Leibnitzis fecorr.A
aiiumes the quadruple penetration as the proof of the
quadruple force of a body having twice the velocity
he has not confidered that a double time is employed
during this penetration. But a double force, acW
equably during a double time, fhould produce a qua-
a™ rZZ , ^bls Clrcumftance is loft fight of in all
t ic fads which this philofopher has adduced. It may
however, be obferved, that Leibnitz, as well as his
o.lowers, holds no difference cf opinion in all the con-
lequences which are deduced from the meaiure which
is here adopted. They admit, that a force producing
an uniformly accelerated motion muft be conftant: they
agree with the followers of Des Cartes in the valuation*
T? of accelerating and defleding forces ; and have
aniduouuy and iuccefsiully cultivated the philofoohy of
Newton, which proceeds on the principle of eftimating
the meaiure of moving forces by the velocity gene-
It ought here to be obferved, that mcvinjforcsjMoving
only are taken into confideration. When a ball hasforces only
acquired a certain velocity, whether it has been ]rn_C011lidereti.
pelled by the elafi icily of the air, by a fpring, or firuck
ofr by a blow, or urged forward by means of a ftream
of air or water, or has obtained its velocity by falling •
m all thefe cafes it is conceived that it has fulfoiaed the
lame adion of moving force. The only diftind no¬
tion, perhaps, which we are able to form, is preffure ;
but
4
Part II. D Y N A
Of Moving but it is from experience that we derive the information
Forces t^at preffure produces motion. Whatever may be the
^^7^ difference of the circumftances of mechanical forces, in
the molt one, namely, production of motion, they all agree.
diftmCt no- In this circumftance of refemblance they are capable of
tion of mo- comparifon •, and from this they derive a name, moving
ving force, y^rce?, which is expreffive of this companion. And
therefore the particular faculty of preffure,. elafticity,
&c. may be meafured by the change of motion produ¬
ced by preffure. In whatever proportion preffure may
aft on a body in a ftate of relt, the magnitude of the
change of motion meafures the preflure actually exerted
in its production •, and as this is the only change of me¬
chanical condition effected' by the preffure in the body
moved by it, it may be meafured by the velocity.
When, therefore, preffure produces the fame change of
velocity on a foft clay ball, the preilure really exerted
is the fame whether the velocity has been augmented or
diminiihed. In both cafes the fame dimple will be ob-
ferved. The changes of motion, therefore, are propor¬
tional to the exerted preffures.
Notions of 132. The notions which we form of a conllant or
conftant invariable force lead to the fame conclufion. By fuch
foice the a £orce equal effects or changes of motion are produced
*ame' in equal times. But equal augmentations of motion are
equal augmentations of velocity. I his notion of an
invariable accelerating force is confirmed by what is
obferved in the cafe ol a falling body, which receives
equal additions of velocity in equal times } and this
force, fo far as we know, is invariable. The inference
then is, that whatever be the force exerted in one le-
cond, it will be four times as much in four feconds.
And this is really the cafe, if it be granted that a qua¬
druple velocity is the indication of a quadruple force ;
but it does not hold in any other eftimation of force.
Befides, it may be obferved, that four fprings applied
to an ounce ball impel it only twice as fait as one
fpring does; and if the fame four fprings be applied to
a four ounce ball, they produce in it the fame velocity
that one fpring produces on an ounce ball. In the lait
cafe, it may be demonitrated, that the four fprings act
during the fame time with one fpring.
Change of 133- The proper meafure, therefore, of a changing
motion the force is a change of motion in all its circumilances of
meafure of velocity and direction. This alio is the proper mea-
^dmown *'ure a moving force. ’ For, in different Hates of mo-
£^cem0Ving tion, bodies may fuitain the fame change of motion.
Suppofmg then one of thefe bodies to be previoufly in a
Hate of reft, the change and the motion acquired are
the fame thing. The force, therefore, producing a
change of motion in a moving body, is precifely the
fame with that force which produces in a body, pre¬
vioufly at reft, a motion equivalent to this change 3
and in this cafe it is Amply a moving force.
This opinion of Leibnitz about the meafure of forces
has influenced the fentiments of many writers, and in
the mechanical inveftigations of fome of them, has not
a little affected their practical deductions. No difpute
probably could have occurred if philofophers had not
been led to confider force as fomething exifting in
body 3 the term on the contrary being only ufed to ex-
prefs the phenomenon, which is conceived to be its
full effect and adequate meafure. The Ample change
of motion obferved is the meafure of the force by which
it is produced..
M I C S. ^ 4«7'
The following is the enunciation, adapted to the cha- Of Moving
rafteriftic and meafure of a change of motion. , ; s ,
Law of the Changes of Motion.
Prop. XII.
134. In every change of motion, the new motion is
compounded of the former motion, and of the motion,
which the changing produces in a body at ref.
Let the change of motion be from AB (fig. 23.) to
AD, this new motion AD is compounded of the for¬
mer motion AB and of the motion AC.
For it has been (hewn, that the change in any mo¬
tion, is that motion, which when compounded with the
former motion, produces the new motion 3 and the new
motion (55.) is the compound of the former motion
and the changing motion. Since then the change of
motion is the mark and meafure of the changing force
(133.) by which both the direction and intenfity or ve¬
locity produced, are determined, the truth ot the pro-
pofition will appear of courle.
133. It has been already obferved (54.), that the
compofition of motions and the fimilar compolition ot
forces are very different things. The firft is a pure ma¬
thematical truth ; the fecond, is a phyfical queftion de¬
pendent on the nature of the mechanical forces as they
exift in the univerfe. Our notions are not very diftinct
of two forces, each of which feparately produces mo¬
tions, having the directions and velocities expreffed by
the tides of a parallelogram, producing by their joint
adtion a motion in the diagonal. The demonftrations
which have been frequently given, are altogether in-
conclufive, and only include the compolition of mo¬
tions 3 while gratuitous poftulates have been affumed by
thofe who endeavoured to accommodate their reafon-
ings to phyfical principles. The celebrated Daniel
Bernoulli gave the firft legitimate demonftration ox this
propofition, in which, however, he employs a teries of
many propofitions, fome of which are very abftruie. It
was greatly limplified by D’Alembert, Mem. Acad,
dcs Sciences 1769, Hill, however, requiring many pro¬
pofitions. Ingenious demonftrations have alfo been gi¬
ven by other celebrated mechanicians. In the follow¬
ing demonftration by Profeffor Robiibn, this diftinguiiti-
ed philofopher has attempted to combine the demou-
ftration of Bernoulli, D’Alembert, and others, thus
rendering it more expeditious, and at the fame time le¬
gitimate. This demonftration is entirely limited to
preffures, without at all confidering or employing the
motions fuppofed to be produced by them.
(A) If two equal and oppofite preffures or incite¬
ments to motion aft at once on a material particle, it
fuffers no change of motion 3 for if it yields in either
direftion by their joint aftion, one of the preffures pre¬
vails, and they are not equal.
Equal and oppofite preffures are faid TO balance
each other 3 and fuch as balance muft be efteemed equal
and oppofite.
(B) If a and b are two magnitudes of the fame kind,,
proportional to the intenfities of two preffures which aft
in the fame direftion, then the magnitude ei -\~b will
meafure the intenfity of the preffure, which is equiva¬
lent, and may be called equal, to the combined effort
of the other two ; for when we try to form a notion of
preffure as a meafurable magnitude, diftinft from mo¬
tion
,.B8
Of Moving tion or any other efFect of it, we find nothing that we
f lo^ccs- , can meafure it by but another preflure. Nor have we
any notion of a double or triple preffure different from a
preffure that is equivalent to the joint effort of twTo or
three equal preffures. A preffure a is accounted triple
of a preffure by if it balances three preffures, each equal
to b, acting together* Therefore, in all proportions
which can be exprefi'ed by numbers, we muff acknow¬
ledge the legitimacy of this meafurement; and it would
furely be affe&ation to omit thofe which the mathema¬
ticians call incommenfurable.
-f he magnitude o—b, in like manner, muff be ac¬
knowledged to meafure that preffure which arifes from
the joint adlion of two preflures a and b afting in oppo-
fite directions, of which a is the greateft.
(C^) Let ABCD and A.bCd (fig* 24.) be two
rhombufes, wdrich have the common diagonal AC. Let
the angles BA b, DA </, be bifefted by the ffraight
lines AE and AF.
If there be drawn from the points E and F the lines
EG, EH, Yg, Yh, making equal angles on each fide
of EA and FA, and if G^, H// be drawn, cutting
the diagonal AC in I and L : then AI-f-AL will be
greater or lefs than AQ, the half of AC, according as
the angles GEH, ^ F /$, are greater or lefs than
GAH, g A h.
Draw GH, g h, cutting AE, AF, in O and 0, and
draw O 0, cutting AC in K.
Becaufe the angles AEG and EAG are refpectively
equal to AEH and EAH, and AE is common to
both triangles, the fides AG, GE are refpeftively equal
to AH, HE, and GH is perpendicular to AE, and is
bileCled in O ; for the fame reafons, g h is bifeCled in
g. Therefore the lines G y, O 0, H//, are parallel,
and IL is bifefted in K. Therefore AI-j-AL is equal
to twice AK. Moreover, if the angle GEH be greater
than GAH, AO is greater than EO, and AK is great¬
er than K£). Therefore AI-J-AL is greater than
A£) ; and if the angle GEH be lefs than GAH, AI
-j-AL is lefs than A£).
(D) Two equal preffures, aCting in the directions
AB and AC (fig. 25.), at right angles to each other,
compofe a preffure in the direction AD, which bifeCts
the right angle ; and its intenfity is to the intenfity of
each of the conftituent preffures as the diagonal of a
fquare to one of the fides. It is evident, that the di¬
rection of the preffure, generated by their joint aCtion,
will bifeCt the angle formed by their directions ; becaufe
no reafon can be afligned for the direction inclining
more to one fide than to the other.
In the next place, fince a force in the direction AD
does, in faCt, arife from the joint aCtion of the equal
preffures AB and AC, the preffure AB may be con¬
ceived as arifmg from the joint aCtion of two equal
forces fimilarly inclined and proportioned to it. Draw
EAF perpendicular to AD. One of thefe forces muff
be direCted along AD, and the other along AE. In
like manner, the preffure AC may arife from the joint
aCtion of a preffure in the direction AD, and an equal
preffure in the direction AF. It is alfo plain, that the
preffures in the directions AE and AF, and the two
preffures in the direction AD, muff be all equal. And
alfo, any one of them muff have the fame proportion to
AB or to AC, that AB or AC has to the force in the
direction AD, arifing from their joint aCtion.
3
DYNAMIC S.
Part II,
Therefore, if it be faid that AD does not meafure Of Moving
the preffure arifing from the joint aCtion of AB and f'ortes-
AC, let Ad, greater than AD, be its jull meafure,
and make Ad : AB=AB : A^rrAB : Ae. Then
A g and A e have the fame inclination and proportion
to AB that AB and AC have to Ad. We determine,
in like manner, two forces A f and Ag as conitituents
of AC.
Now A r/ is equivalent to AB and AC, and AB is
equivalent to A ^ and Ag ; and AC is equivalent to
Af and Ag. Therefore A d is equivalent to A e,
A-fy A-g, and Ay. But (a) Ae and Ay balance
each other, or annihilate each other’s effeCt ; and there
remain only the two forces or preffures Ay, Ay.
Therefore (b) their meafure is a magnitude equal to
twice A y. But if A be greater than the diagonal
AD qf the fquare, whofe fides are AB and AC ; then
Ay muff be lefs than AI, the fide of the Iquare whofe
diagonal is AB. But twice Ay is lefs than AD, and
much lefs than Ad. Therefore the meafure of the
equivalent of AB and AC cannot be a line A d great¬
er than AD. In like manner, it cannot be a line A §
that is lefs than AD. Therefore it muff be equal to
AD, and the propofition is demonftrated.
Corollary*
Two equal forces AB, AC, aCting at right
angles, wall be balanced by a force AO, equal and op-
pofite to AD, the diagonal of the fquare whofe fides
are AB and AC ; for AO would balance AD, wdiich
is the equivalent of AB and AC.
(Tb) Let AECF (fig. 26.) be a rhombus, the acute
angle of which EAF is half of a right angle. Two
equal preffures, wdfich have the directions and meafures
AE, AF, compofe a preffure, having the direction and
meafure AC, w;hich is the diagonal of the rhombus.
It is evident, in the firft place, that the compound
force has the direCtion AC, which bifeCts the angle
EAF. If AC be not its juft meafure, let it be AP
lefs than AC. Let ABCD be a fquare defcribed on
the fame diagonal, and make AP : AQ = AE : AO,
=zAF : Ae. Draw KOG, Key perpendicular to
AE, AF •, draw Gly, OHe, EG, EK, Fy, FK,
PF, and PE.
The angles CAB and FAE are equal, each being
half of a right angle. Alfo the figures AEPF and
AGEK are fimilar, becaufe AP : AQrrAE : AO.
Therefore FA : AP — KA : AE, and EA : AP —
GA : AE. Therefore, in the fame manner that the
forces AE, AF are affirmed to compofe AP, the forces
AG and AK may compofe the force AE, and the forces
Ay and AK may compofe the force AF. Therefore
(AJ the force AP is equivalent to the four forces AG,
AK, Ay, AK. But (TT) AG and Ay are the fides
of a fquare, whofe diagonal is equal to twice AI :
and the two forces AK, AK are equal to, or are mea-
fured by, twice AK. Therefore the four forces AG,
AK, Ay, AK, are equivalent to 2AI-j-2AK, —
4 AH.
But becaufe AP was fuppofed lefs than AC, the
angle FPE is greater than FAE, and GEK is greater
than GAK, AO is greater than OE, and AH is great¬
er than HQ, and 2 AH is greater than AQ^; and
therefore 4 AH is greater than AC, and much greater
than
Part II. D Y N A
Of Moving than AP. Therefore AP is not the juft meafure of
l forces. ^le force compofed of AE and Ah.
' v' ' In like manner, it is (hewn, that AE and AF do
not compofe a force whofe meafure is greater than AC.
It is therefore equal to AC j and the propofttion is de-
monftrated.
("G^) By the fame procefs it maybe demonftrated,
that if BAD be half a right angle, and EAF be the
fourth of a right angle, two forces AE, AF will com¬
pofe a force meafured by AC. And the procefs may
be repeated for a rhombus whofe acute angle is one-
eighth, one-fixteenth, &c. of a right angle ; that is,
any portion of a right angle that is produced by conti¬
nual bife£lion. Two forces, forming the fides of fuch
a rhombus, compofe a force meafured by the dia¬
gonal. j
(H) Let ABCD, A£c</ (fig. 27.) be two rhom-
bufes formed by two confecutive bifeclions of a right
angle. Let AECF be another rhombus, whofe fides
AE and AF bifeft the angles BA £ and DA (J.
The two forces AE, AF, compofe a force AC.
Bifeft AE and AF in O and 0. Draw the perpen¬
diculars GOH, g 0 h, and the lines GI^, OK 0, HL //,
-and the lines EG, EH, F^-, FA
It is evident, that AGEH and A^F/i are rhom-
bufes j becaufe AO=OE, and A F. It is alfo
plain, that fince b Adis half of BAD, the angle G AH
is half ot b Ad. It is therefore formed by a continual
bife&ion of a right angle. Therefore (G) the forces
AG, AH, compofe a force AE j and Ag, A /i, com¬
pofe the force AF. Therefore the forces AG, AH,
Ag, Ah, aiding together, are equivalent to the forces
AE, AF adting together. But AG, A^- compofe
a forces 2 AI j and the forces AH, A h compofe a
force rr 2 AL. Therefore the four forces adling to¬
gether are equivalent to 2AI-I-2AL, or to 4 AK.
But becaufe AO is 4 AE, and the lines Gg, O-o, H h,
are evidently parallel, 4 AK is equal to 2 AQ^, or to
AC $ and the propofition is demonftrated.
Corollary.
(I) Let us now fuppofe, that by continual bifedlion
of a right angle we have obtained a very fmall angle a
of a rhombus j and let us name the rhombus by the
multiple of a which forms its acute angle.
The propofition (G) is true of a, 2 a, 4 a, &c. The
propofition (HJ is true of 3 a. In like manner, be¬
caufe (G) is true of 4*7 and 8 a, propofition (Tf) is
true of 6 a ; and becaufe it is true of 4 <7, 6 a, and 8 a,
it is true of 5 <7 and 7 a. And fo on continually till
we have demonftrated it of every multiple of a that is
lefs than a right angle.
(K) Let R AS (fig. 28.) be perpendicular to AC,
and let ABCD be a rhombus, whofe acute angle BAD
is fome multiple of 2 77 that is lefs than a right angle.
Let Abed ho another rhombus, whofe fides Ab, Ad
bifedl the angles R AB, SAD. Then the forces A b,
A d compofe a force AC.
Draw £R, d§ parallel to BA, DA. It is evident,
that AR. £ B and ASt/D are rhombufes, whofe acute
angles are multiples of a, that are each lefs than a
right angles Therefore (I) the forces AR and AB
compofe the force Ab, and AS, AD compofe Ad;
but AR and AS annihilate each other’s effedt, and
there remains only the forces AB, AD. Therefore
V.OL. VIL Part IL
M I C S. 489
Ab and Ad are equivalent to AB and AD, which Of Moving-
compofe the force AC j and the propofition is demon- , * 01 ‘e^' ,
ftrated.
Corollary.
CL) Thus is the corollary of laft propofition extend¬
ed to every rhombus, whofe angle at A is fome multi¬
ple of a lefs than two right angles. And fince a may
be taken lefs than any angle that can be named, the.
propofition may be confidered as deinonftrated of every
rhombus 5 and we may fay,
,(M) Two equal forces, inclined to each other in any
angle, cotnpofe a force which is meafured by the diagonal
of the rhombus, whofe fdes are the meafures oj the con-
Jlituent forces.
(N) Two forces AB, AC (fig. 29.) having the di-
redtion and proportion of the fides of a redlangle, com¬
pofe a force AD, having the diredtion and proportion
of the diagonal.
Draw the other diagonal CB, and draw EAF paral¬
lel to it j draw BE, CF parallel to DA.
AEBG is a rhombus •, and therefore the forces AE
and AG compofe the force AB. AFCG is alfo a
rhombus, and the force AC is equivalent to AF and
AG. Therefore the forces AB and AC, adting toge¬
ther, are equivalent to the forces AE, AF, AG, and
AG adling together, or to AE, AF, and AD adling
together: But AE and AF annihilate each other’s ac¬
tion, being oppofite and equal (for each is equal to the
half of BC). Therefore AB and AC adling together,
are equivalent to AD, or compofe the force AD.
(O) Two forces, which have the diredlion and pro¬
portions of AB, AC (fig. 30.) the fides of any paralle¬
logram, compofe a force, having the diredlion and pro¬
portion of the diagonal AD.
Draw AF perpendicular to BD, and BG and DE
perpendicular to AC.
Then AFBG is a redlangle, as is alfo AFDE j and
AG is equal to CE. Therefore (W) AB is equivalent
to AF and AG. Therefore AB and AC adling to¬
gether, are equivalent to AF, AG, and AC adling to¬
gether ; that is, to AF and AE adling together 5 that
is (N) to AD j or the forces AB and AC comppfe
the force AD.
Hence arifes the moll general propofition.
If a material particle be urged at once by two pref- Compofi-
fures or incitements to motion, whofe intenjities are pro-how of all
portional to the fdes of any parallelogram, and which incitements!
aSl in the directions of thofe Jides, it is ajfeEled in thet0 motlon'
fame manner as if it were acted on by a fngle force,
whofe intenfty is meafured by the diagonal of the paral ¬
lelogram, and which a bis in its direction : Or, two pref-
fures, having the direblion and proportion of the fdes of
a parallelogram, generate a prefure, having the direc¬
tion and proportion of the diagonal.
136. Thus is demonftrated from abftradl principles
the perfedl fimilarity of the compofition of preffirres and
the compofition of forces mealured by the motions which
are produced. A feparate demonllration feems indif-
penfably necefiary ; for \vhat may be deduced from the
one cafe is not always applicable to the other. The
change produced on a motion already exifting by a de-
lledl'ing force, cannot be explained by any compofition
of preflures •, becaufe the changing prefiure is the only
one that exifts, and there is none with which it may be
3 ’ compounded.
49° D Y N A
Of Moving compounded. Nor, on the other hand, will our no-
. Forf es , tions of the compofition of motions explain the compo-
fition of preffures, without affuming that the preffures
are proportional to the velocities.
137. Confidering' this law of motion merely as a uni-
verlal fa6t or phylical law, abundant proof may be ad¬
duced in fupport of it.
1. I he joint action of different forces is quite fami-
liar. A lighter, for example, is dragged in different
direftions by two ropes on different Tides of the canal,
the lighter moving in an intermediate dire&ion, as if
dragged in that direction by one rope only. A ball
moving in a particular direction, which receives a Itroke
acrofs this direction, takes a direction lying between
that of the firft motion and that of the tranfverfe
ftroke.
2. If a particle of matter A (fig. 23.) be urged at
once by two preffures in the directions AB and AC;
and if AB and AC be proportional to the intenfities ef
thofe preffures, the joint action of thefe two preffures is
Equivalent to the aCtion of a third preffure in the direc¬
tion of the diagonal AD, and having its intenfity in
the proportion of AD. This is proved by obferving,
that the point A is withheld from moving by a preffure
AE, which is equal and oppofite to AD. But pref¬
fures are moving forces, producing velocities when they
aft fimilarly during equal times, proportional to their
intenfities. The proportion, therefore, is true with re-
fpeft to preffures, confidered merely as fuch, and alfo
•with refpeft to the motions which may be produced by
their compofition.
3. The weight of a ball which is fufpended by a
thread, and drawn afide from its pofition in a ftate of
reft, urges it downwards, and the ball is fupported ob¬
liquely by the thread. Suppofmg this propofition to be
true, the direftions and intenfities of the forces inciting
it to motion in any pofition, as well as the refult of the
velocities, can be precifely afccrtained.
4. The motions of the planets computed on thefe
principles of the compofition of forces, do not exhibit
any perceptible deviation from calculation, at the end
of thonfands of years.
Nothing, therefore, can be relied on with greater
confidence than the perfeft agreement betiveen the com¬
pofition of motions, and the compofition of the forces,
which, feparately taken, would produce thofe motions,
and which are meafured by the velocities produced.
But it ought to be remarked, that if the moving forces
are meafured by the fquares of the velocities which they
generate, the compofition cannot poftibly hold ; name¬
ly, from two forces which are reprefented by the fides
of a parallelogram made proportional to the fquares of
the velocities, there will not refult a force which can
be reprefented by the diagonal. But fuppofmg the
compofition of forces to be as the velocities, nature ex¬
hibits them exaftly.—This propofition, therefore, whe¬
ther it be confidered as an abftraft truth or as a phyfl-
oal law, may be received as fully eftabliftied. The fol¬
lowing is the converfe of this propofition.
Prop. XIII.
138. The force hy which the jnotion AB is changed
into AD, is that which would produce in a body at ref
the motion AC, and this compounded with AB produces
the obfsrved motion AD,
M I C S. Part IT.
Prop. XIV. Of Moving
F°rces.
139. The force which will produce in a bod if at rejl /
a motion having the dire&ion and velocity reprefented by
AC, when applied to a body moving with the velocity
and in the direction AB, will change its motion into the
motion AD, which is the diagonal of the parallelogram
ABDC. For the new motion muft be that which is
compounded of AB and AC, that is, it muft be the
motion AD.
I he combination of thefe two propofitions gives life
to the following, which is ftill more general.
Prop. XV.
X 40. A body A being urged at once by two forces,
which feparately would caufe it to deferibe AB and AC,
the fdes of a parallelogram ABDC, the body by their
joint action will deferibe the diagonal AD in the fame
time.
For if the body had been already moving with the
velocity and in the direftion AB, and if it had been
afted on in A by the force AC, it would deferibe AD
in the fame time. But it matters not at what time it
acquired the determination to deferibe AB. Let it be
then at the inftant that the force AC is applied to it.
And becaufe its mechanical condition in A, which has
the determination to the motion AB, is the fame as in
any other point of that line, it muft deferibe AD.
Corollary.
Two forces aBing on a body in the fame or in oppo¬
fite direBions, will caufe it to move with a velocity equal
to the fum or to the difference of the velocities which it
would have received from the forces feparately. For, if
AC approach continually to AB by diminiftiing the
angle BAC, the points C and D will at laft fall on c
and d, and then AD is equal to the fum of AB and
AC. But if the angle BAC increafe continually, the
points C and D will at lart fall on » and 2, and then
A 2 becomes equal to the difference of AB and AC.
In the laft cafe, it is evident, that if AC be equal to
AB, the point D or 5 will coincide with A, and the
two forces being equal and afting in oppofite direftions,
there will be no motion.
141. In fuch cafes the equal and oppofite forces AC
and AB are faid to balance each other; and it is gene¬
rally faid, that thefe forces, by whofe joint operation
no change of motion is produced, balance each other.
Such forces are accounted equal and oppofite, each
producing on the body a change of motion equal to
what it would produce on a body at reft, and at the
fame time equal to the motion produced by the other
force on a body at reft. The two motions being equal
and oppofite, the forces are therefore equal and op¬
pofite.
142. What has been demonftrated concerning the
affeftions with refpeft to the afteftions of compound
motions, may now be applied to the combination of
forces; taking care, however, to recolleft the effential
difference between the compofition of motions and the>
compofition of forces. In the combination of forces,
the compofition is complete, when the determination
has been given to the body to move with the proper ve¬
locity in the diagonal. When the body has acquired
this determination, there is no farther compofition ; and
it continues its uniform motion, till its condition be
changed.
D Y N A
g changed by Tome new force. On the other hand, in
the compolition of two or more motions, the conihtuent
motions are fuppofed to continue •, and it is only during
their continuance that the compound motion exi Is. it
it be poflible, which does not appear to be the erne that
any force can generate a finite velocity by its milanta-
neous action, two fuch forces generate m an mftant the
determination in the diagonal. But luppofing the ac¬
tion to continue for fome time, to generate the veloci-
cities AB or AC, there mull be a continuance ot the
■joint aftion during the fame time to produce the velo¬
city AD. And although the moving powers ol the
two forces may vary in their intenfity, yet it is necet-
fary that they retain the lame proportion to. each other
during the whole time of their joint athon. Over¬
looking this circumftance, experiments' have been made
for the purpofe of comparing this dodtrine with the
phenomena •, and they have been found to exhibit very
different refults. But experiments made by the com i-
nation of preffures, fuch as weights pulling a body by
means of threads, coincide precifely with this doctrine ,
for it is always found that two weights pulling m the
directions AB, AC, and proportional to thofe lines
are balanced by a third weight m the proportion ot
AD and pulling in the direction AE. In this nay
the compofition of preffures is clearly proved and, ha¬
ving no other diltinCt conception of a moving force,
thefe experiments may be confidered as lufficient. But
we may go farther-, for there is the clearelt proof by
experiment, that preffures produce motions in propor¬
tion to their intenfities by their fimilar aCtion during
equal times. In the planetary motions, the direaions
and intenfities of the compound forces are accurately
known as moving forces. Thefe motions afford a com¬
plete proof of the phyfical law,, by their perfeft coinci¬
dence with the calculations which proceed on the prin¬
ciples of this doCfrine. This coincidence muff be ac¬
knowledged as a ffdl proof of the propriety of the mea¬
sure which has been affumed. I he affumption of any
other meafure would exhibit refults quite different from
the phenomena. # ,
143. Forces which produce motions along the lides
of a parallelogram are called Jtjnfile forces or covjhtuent
forces. And" the force which fmgly produces the mo¬
tion in the diagonal, is called the equivalent force, the
-compound force, or the ref lilting force.-
144. Some general conclufions may now be pointed
out, which wili facilitate greatly the ufe of the paral¬
lelogram of forces.
General Corollaries.
1. The conflituent and the refulting forces, or the
fimple and compound forces, aft in the fame plane }
for‘the fides and diagonal of a parallelogram are in one
plane.
■2. The fimple and the compound forces are propor¬
tional to the fides of any triangle which are parallel to
their direftions. For if any three lines ab, bd, ad be
drawn parallel to AB, AC, and AD (fig. 31.), they
will form a triangle fimilar to the triangle ABD.
;For the fame reafons they are proportional to the lides
of a triangle a'b'd, which are refpeftively perpendicular
to their direftions. _
3. Therefore each is proportional to tne fine or the
oppofite angle of this triangle j for the fides of any tri-
M I C s. 491
angle are proportional to the fines of the oppofite Of^Mo.mg
angles. „ , . v——-y——'
4. Each is proportional to the fine of the angle con¬
tained by the direftions of the other two j for AD is
to AB as the fine of the angle ABD to the fine ot
the anode ADB. Now the line of ABD is the lame
with the line of BAG contained between the directions
AB and AC, and the fine of ADB is the lame with
the line of CAD ; alfo AB is to AC, or BD, as the
fine of ADB (or CAD) to the line of BAD. .
145. Let us now proceed to the application of t^is Special ufes
fundamental propolition. And we obferve, m the rft ralle'lo^raril
place, that fince AD may be the diagonal ot an mcle- of forces#
finite number of parallelograms, the motion or the prel-
fure AD may refult from the joint aftion of many pairs
of forces. It may be produced by forces which would
feparately produce the motions AF and. AG. Ibis
generally gives us the means of difeovering the forces
which concur in its produftion. If one of them, AB,
is known in direftion and intenfity, the direftion AC,
parallel to BD, and the intenfity, are difeovered. Some¬
times we know the direftions of both. Then, by-
drawing the parallelogram or triangle, we learn then-
proportions. The force which detlefts any motion
AB into a motion AD, is had by Amply drawing a
line from the point B (to which the body would have
moved from A in the time of really moving from A to
D) to the point D. The deflefting force is fuch as
would have caufed the body move from B to D in the
fame time. And, in the fame manner, we get the
compound motion AD, which ardes from any two im
pie motions AB and AC, by fuppofing both of the mo¬
tions to be accomplilhed in luccellion. I he final place
of the body is the fame, whether it moves along AD
or along AB and BD in fucceflion.
146 This theorem is not limited to the compofition Equivalent
of two forces only 5 for fince the combined aftion offt tnany
two forces puts the body into the fame ftate as it then-
equivalent alone had afted on it, we may fuppofe this
to have been the cafe, and then the aftion of a tlnrd
force will produce a change on this equivalent motion.
The refulting motion will be the Erne as if only this
third force and the equivalent of the other two had
afted on the body. Thus, in fig. 32. the three forces
AB, AC, AE, may aft at once on a particle ot mat¬
ter. * Complete the parallelogram ABDC ; the diago¬
nal AD is the force which is generated by AB and
A 0 Complete the parallelogram AEJ D j the dia-
J.'w CV. i&avs —£->-;  ' .
gonal AF is the force refulting from the combined ac¬
tion of the forces AB, AC, and AE. In hke man¬
ner, completing the parallelogram AGHF, the diago¬
nal API is the force refulting from the combined ac¬
tion of AB, AC, AE, and AG, and fo on of any
number of forces.
This refulting force and the refulting motion may
be much more expeditioufly determined, in any. degree
of compofition, by drawing lines in the proportion and
direftion of the forces in fucceflion, each from the end
of the preceding. Thus, draw AB, BD, DF, FH,
and join AH j AH is the refulting force. The de-
monllration is evident.
147. In the compofition of more than two lorces,
we are not limited to one plane. I he force AD is m
the fame plane with AB and AC j but AE may be
elevated above this plane, and AG may lead beiow it.
o n Ai?
492 D Y N A
Of Moving A F is in flic plane of AD and AE, and AH is in the
, t plane of AF and AG.
Complete the parallelograms ABLE, ACKE
ELFK. It is evident that ABLIKCX) is a paral-
lelopiped, and that AF is one of its diagonals. Hence
we derive a more general and very ufeful theorem.
Three forces having the proportion and direction 'of the
three Jides of a parallelopided, compofe a force having
the proportion and dir eel ion of the diagonal.
148. In the inveftigation of very complicated pheno¬
mena, the mechanician confiders every force as refulting
fiom the joint action of three forces at right angles to
each other, and he takes the lum or difference of thefe
in the lame or oppolite directions. IThus he obtains the
three tides of a parallelepiped, and from thefe computes
the pofition and magnitude of the diagonal. This is
the force refulting from the compofition of all the par¬
tial ones. This procefs is called the ejlimation or re¬
duction of forces. Forces may be eitimated in the di¬
rection of a given line or plane, or they may be redu¬
ced to that direction, as has been done with refpeCt to
motion. See Cor. 2. Propof. 9. in Art. 57.
I he laws of motion which have now been confider-
ed, are neceffary confequences of the relations of thofe
conceptions which we form of motion and mechanical
force, and they are univerfal faCts or phyfical laws.
To thefe Sir Ifaac Newton has added another, which is
the following.
Third Law of Motion.
149. Every a flion is accompanied by an equal and
contrary rcaftion, or the aBions of bodies on one ano¬
ther ai e always mutual, equal, and in contraru direc¬
tions. ^
In all cafes which can be accurately examined, this
holds to be a univerfal faCt. Newton has made this
affirmation on the authority of what he conceives to be
a law of human thought ; namely that the qualities
dilcovered in all bodies on which experiments and ob-
iervations can be made, are to be confidered as univer¬
fal qualities of body. But if the term law of motion
be limited to thofe confequences that neceflarily flow
from our notions of motion, of the caufes of its produc-
tion and changes, this propofition is not fuch a refult.
Becaufe a magnet caufes the iron to approach toward
it, it by no means follows from this oblervation that
tne preflure of the iron fhall be accompanied by any
motion or change of Hate of the magnet, or it does not
appear to be neceffarily fuppofed that the iron attracts
tne magnet. When this was obferved, it was account¬
ed a difeovery, and a difeovery which is to be aferibed
to the modems. Hr Gilbert, who firll: mentions it, af¬
firms that the magnet and the iron are obferved mutu¬
ally to attract each other, as well as all ele£frical fub-
itances, and the light bodies which are attracted by
them. Phe difeovery was made by Kepler that a mu¬
tual attraaion exifts between the earth and the moon.
Newton difeovered that the fun ads on the planets, and
that the earth acls on the moon. It had been obferved
too by Newton that the iron reaas on the magnet, that
the aaions of electrified bodies are mutual, and that all
the aaions of folid bodies are accompanied by an equal
and contrary reaaion. On the authority of the rule of
philofophizing which he had laid down, he affirmed
that the planets reaa on the fun, and that the fun is
M 1 c s- Part IL
not at reft, but is continually agitated by a fmall mo- Of Movin?-
tion round the general centre of gravitation ; and he Forces.
pointed out feveral of the confequences of this reaaion. -v—
As the celeftial motions were more narrowdy examined
by aftronomers, thefe confequences were found to ob¬
tain, and to produce difturbances in the planetary mo¬
tions. This reciprocity of aaion is now found to hold
v’lth the utmoft precifion through the whole of the fo-
lar fyftem j and therefore this third propofition of New¬
ton is to be confidered as a law' of nature. And it is
true with refpea to all bodies on which experiment or
obfervation can be made.
. I5°* Tim then being a univerfal law, we cannot
diveft our minds of the belief that it depends on a ge¬
neral principle, by which all the matter in the univerfe
is influenced. It ftrongly induces the perfuafion of the
ultimate particles of matter being alike, that a certain
number of properties belong in the fame degree to each
atom, and that all the fenfible differences of fubftance
which are pbferved, arife from a different combination
of thofe primary atoms in the formation of a particle of
thofe fubftances. All this is no doubt perfe&ly pof-
fible. But if each primary atom be fo conftituted, no
adion of any kind of particle or colle&ion of particles
can take place on another, which is not accompanied
by an equal readion in the oppofite diredion.
151. Let us now dired our attention to the applica¬
tion of thefe laws. This anfwers a twofold purpofe.
The firft is to difeover the mechanical powers of natu¬
ral fubftances by which they are fitted to become parts
of a permanent univerfe. This is accompliflied by ob-
ferving the changes of motion which always accompany
thofe fubftances. It is from thefe changes that the on¬
ly charaderiftics of powers are derived 5 and thus is dif¬
eovered the power of gravity, of magnetifm, &c. Ano¬
ther purpofe in the employment of thefe law's is, that,
after having obtained the mechanical charader of any
fubftance, w'e may afeertain what wall be the refult of
its being in the vicinity of the bodies mechanically al¬
lied, or we may afeertain wffiat is the change induced
on the condition of the neighbouring bodies.
152. The mechanical powers of bodies occafionally
produce. accelerations, retardations, and defledions in
the motions of other bodies. Thefe names have been
given, becaufe nothing is known of their nature, or of
the manner in which they are effedive j they are there¬
fore named, as they are meafured by the phenomena
which are obferved and confidered as their effeds. Let
us now attend a little to the principal circumftances re ¬
lating to the adion of thefe forces.
Of Accelerating and Retarding Forces.
153. Changes of motion are the only marks and
meafures of changing forces; and having no other
mark of the force but the acceleration, it has obtained
the name of an accelerating force. When the motion
is retarded it is called retarding force. Nor is there any
other meafure of theintenfity of an accelerating force, but
the acceleration which it produces. To inveftigate there¬
fore the powers which produce all the changes of mo¬
tion it is neceflary to obtain meafures of the accelera¬
tion. What has been faid of accelerations and retarda¬
tions of motion is equally deferiptive of the effeds of ac¬
celerating and retarding forces. Hence the following
propofition-
V
part II. DYNAMIC 5.
of Moving If the abfcijja a d fig. 5- repnfmt the time of any mo- Corollary.
Forces tion, and if the areas a b f e, .a c g e &c. are as the ve- The momentary change on the fquare cf the velocity
locities at the infants b c, &c. the ordinates a e, b f, c g, ag force? anci as the fmall portion of ipace along
&c. are as the accelerating forces at thofe infants* which it acts, jointly }
Corollaries. v v ~ fs
493
Of Moving
Forces.
Cor. I. The momentary change of velocity is as the
force/ and the time r jointly. It maybe thus ex-
preffed.
or—roff t.
Alfo, the accelerating or retarding force is proportional
to the momentary variation of the velocity, directly, and
to the moment of time in which it is generated, in-
verfely (48).
Indeed, all that we know of force is that it is fome-
thing which is always proportional to -j •
Cor. 2. Uniformly accelerated or retarded motion is
the indication of a confant or invariable accelerating
force. For, in this cafe, the areas a bfe, a c g e, &c.
increafe at the fame rate with the times a b, a c, &c.
and therefore the ordinates a e, bf eg, &c. mull all be
equal •, therefore the forces reprefented by them are the
fame, or the accelerating force does not change its in-
tenfity, or, it is conilant. If, therefore, the circum-
llances mentioned in articles 37 are okierved
in any motion, the force is conilant. And if tne force
is known to be conftant, thofe propofitions are true ref-
pecling the motions. _ .
Cor. 3. No finite change of velocity is generated in
an infant by an accelerating or retarding^ force. For
the increment or decrement of velocity is always ex-
preifed by an area, or by a produfl//, one fide or fa&or
of which is a portion of time. As no finite fpace can
be deferibed in an inftant, and the moveable mull pafs
in fuccefiion through every point of the path, fo it mull
acquire all the intermediate degrees of velocity. It mult
be continually accelerated or retarded.
Cor. 4. The change of velocity produced in a body
in any time, by a force varying in any manner, is the
proper meafure of the accumulated or whole aclion of
the force during this time. For, fince the momen¬
tary change of velocity is expreffed by /;, _ the aggre¬
gate of all thefe momentary changes, that is, the whole
change of velocity, mull be exprelted by the fum of all
the quantities f t. This is equivalent to the area of
the figure employed in art. 148) and may be exprelfed
by//.
154. If the abfcijfa AE (fig. 8.) of the line sice be
the path along which a body is urged by the a&ion of a
force, varying in any manner, and if the ordinates A a,
B C c, &.c. be proportional to the mten/ities of the
force in the different points of the path, the intercepted
areas will be proportional to the changes made on the
fquare of the velocity during the motion along the corre-
fponding portions of the path.
For. by art. 49, the areas are in this proportion when
the ordinates are as the accelerations. But the accelera¬
tions are the meafures of, and are therefore proportional
to, the accelerating forces. Therefore the propofition is
manifelt.
v v
and /= ~
s
155. It deferves remark here, that as the moment^
ary change of the fimple velocity by any force/depends.
only on the time of its aftion, it being — // (148.) Cor.
1. fo the change on the fquare of the velocity depends on
the fpace, it being — fs. It is the fame, whatever is
the velocity thus changed, or even though the, body be
at relt when the force begins to aft on it. Thus, m
every fecond of the falling of a heavy body,, the \ e-
locity is augmented 3 2 feet per fecond, and in every
foot of the fall, the fquare of the velocity increafes
by 64- r .
156. The whole area AE e a, expreffed by J f s,
expreffes the whole change made on the fquare of the
velocity which the body had in A, whatever this velocity
may have been. ’We may therefore fuppofe the body to
have been at rell in A. 1 he area then meafures the
fquare of the velocity which the body has acquired in
the point E of its path. It is plain that the change on
•y1 is quite independent on the time of aftion, and there¬
fore a body, in pafling through the fpace AE with any
initial velocity whatever, fuftains the lame change of the
fquare of that velocity, if under the influence of the
fame force. .
13 7. This propofition is the fame with the 39^1
the Firft Book of Newton’s Principia, and is, perhaps
the moll generally ufeful, of all the theorems in. Dyna¬
mics, in the folution of praftical queftions.. It is,to be
found, without demonflration, in his earlielt writings,
the Optical Leftures, which he delivered in 1669 and
following years.
158. One important ufe may be made of it at pre-
fent. It gives a complete folution of all the fafts which
were obferved by Dr Hooke, and adduced by Leibnitz
with fuch pertinacity in lupport of his meaiure of, the
force of moving bodies. All of them are of precifely
the fame nature with the one mentioned in art. 157’ or
with the faft, “ that a ball projefted direftly upwards
“ with a double velocity, will rife to a quadruple height,
“ and that a body, moving twice as fait, will penetrate
“ four times as far into a uniformly tenacious mafs.
The uniform force of gravity, or the uniform tenacity
of the penetrated body, makes a uniform oppofition to
the motion, and may therefore be confidered as a uni¬
form retarding force. It will therefore be repiefented,
in fig. 8, by an ordinate always of the fame length, and
the areas which meafure the fquare of the velocity loft-
will be portions of a reftangle AE 1 a. If therefore A E
be the penetration neceffary for extinguifliing the velo¬
city 2, the fpace AB, neceffary for extinguifhing the
velocity 1, muff be L of AE, becaule the fquare of 1
is ^ of the fquare of 2.
159. What particularly deferves remark here, is,
that this propofition is true, only on the fuppoftion that
forces are proportional to the velocities generated by them
in equal times. For the demonftration of this propofition
proceeds entirely on the previoufly eftablifhed meaiure
494 D Y N A
0fForcesnS 0t' ac“lMation. We had V = f i; therefore v v~ft V.
.-'■ii - - v— > But t vzz.s ; therefore v v f which is precifely
this propofition.
160. Ihofe may be called _/5W./hr points of fpace,
and /imi/ar inftants of time, which divide given portions
o! fpace or time in the lame ratio. Thus, the beginnino-
Ot the 5th inch, and of the 2d foot, are limilar points
ot a foot, and of a yard. The beginning of the 2ill
minute, and of the 9th hour, are limilar inftants of an
hour, and of a day.
h orces may be /aid to act fwiilarly when, in limilar
inftants of time, or limilar points of the path, their in-
tenlities are in a conftant ratio.
161. Lemma. If two bodies be limilarly acceler¬
ated during given times a c and h k (fig. 33.), they are
allb limilarly accelerated along their refpeiftive paths
AC and HK.
Let a, b, c be inftants of the time a c, fimilar to the
inftants h, z, k of the time h k. Then, by the limilar
accelerations, we have the force a e : h l—b f: im. This
being the cafe throughout, the area fly is to the area hm
as the area ay to the area h n. Thefe areas are as the
velocities in the two motions 48. Therefore the velo¬
cities in fimilar inftants are in a conftant ratio, that is,
the velocity in the inilant b is to that in the inllant
t, as the velocity in the inftant c to that in the in-
ftant k.
The figures may now be taken to reprefent the times
of the motion by their abfciffae, and the velocities by
their ordinates, as in art. 28. The fpaces defcribed are
now reprefented by the areas. Thefe being in a con¬
ftant ratio, as already Ihewn, we have A, B, C, and
•H, I, K, fimilar points of the paths. And therefore, in
fimilar inftants of time, the bodies are in fimilar points
of the paths. But in thefe inftants, they are fimilarly
accelerated, that is, the accelerations and the forces are
in a conftant ratio. They are therefore in a con¬
ftant ratio in fimilar points of the paths, and the bo¬
dies are fimilarly accelerated along their refpecftive
paths (155.)
162. If two particles of matter are fmilarly urged
by accelerating ar retarding forces during given times, the
whole changes of velocity are as the forces and times joint¬
ly ; or v ±: f t.
For the abfcifile a c and h h will reprefent the times,
and the ordinates a e and h l will reprefent the forces,
and then the areas will reprefent the changes of velo¬
city, by art. 47. And thefe areas are as a c X a e to
hk X hi.
Hence t
V 1 r - v
-y, and/=-.
163. If two particles of matter are fmilarly impel¬
led or oppofed through given fpaces, the changes in the
fquares of velocity are as the forces andfpaces jointly ;
or ~ f s.
This follows, by fimilar reafoning, from art. 49.
It is evident that this propofition applies directly to
the argument fo confidently urged for the propriety of
the Leibnitzian meafure of forces, namely, that four
fprings of equal ftrength, and bent to the fame degree,
generate, or extinguifli only a double velocity.
164. If tiro particles of matter are fimilarly impelled
through given fpaces, the fpaces are as the forces and the
fquares of the times jointly.
2
M ^ C S* part IJ.
For the moveables are fimilarly urged during the Of Moving
times of their motion (converfe of 1 $6.) Therefore F°‘ces-
v -=zft, and v% rr/21% ; but (T58J v% ~fs. There- ' V~W
fore/r dpf1 P and s dzf t\
Corollary.
That is, the fquares of the
times are as the fpaces, dire&ly, and as the forces,
inverfeiy ; and the forces are as the fpaees, diredlly,
and as the fquares of the times, inverfeiy.
165. The quantity of motion in a body is the fum
of the motions of all its particles. Therefore, if all are
moving in one direction, and with one velocity v, and
if m be the number of particles, or quantity of mat¬
ter, m v will exprefs the quantity of motion y, or
q ~ mv.
166. In like manner, we may conceive the acceler¬
ating forces f which have produced this velocity v in
each particle, as added into one fum, or as combined
on one particle. They will thus compofe a force,
which, for diftinttion’s fake, it is convenient to mark
by a particular name. We fhall call it the MOTIVE
force, and exprefs it by the fymbolp. It will then be
confidered as the aggregate of the number m of equal
accelerating forces each of which produces the velo¬
city v on one particle. It will produce the velocity
m v, and the fame quantity of motion q.
167. Let there be another body, confifting of n
particles, moving with one velocity u. Let the moving-
force be reprefented by tt. It is mealured in like manner
by n u. Therefore we have, p : jr— m v : n u, and v : u
~ — : —; that is,
m n
The velocities which may be produced by the f milar
allion of different motive forces, in the fame tune, are di
reBly as thefe forces, and inverfeiy as the quantities of
matter to which they are applied.
In general,
And ./being—j ,
Remark.
168. In the application of the theorems concerning
accelerating or retarding forces, it is neceffary to attend
carefully to the diftinClion between an accelerative and a
motive force. The caution neceffary here has been ge¬
nerally overlooked by the writers of Elements, and this
has given occafion to very inadequate and erroneous no¬
tions of the action of accelerating powers. Thus, if a
leaden ball hangs by a thread, which paffes over a pulley,
and is attached to an equal ball, moveable along a hori¬
zontal plane, without the fmalleit obftruftion, it is known
that, in one fecond, it will defcend 8 feet, dragging the
other 8 feet along the plane, with a uniformly accelerated
motion, and will generate in it the velocity 16 feet per
fecond. Let the thread be attached to three fuch balls.
We know that it will defcend 4 feet in a fecond, and
generate the velocity 8 feet per fecond. Moft readers
are difpofed to think that it fhould generate no greater
velocity than 5-3- feet per fecond, or y of 16, becaufe k
is applied to three times as much matter f 16 2.) The
error
Fart IL . r W •
Of Moving error lies in' confidering tl.e motive force as toe fame m
Forces both ca{e? and iu not attending to the quantity oi mat-
' ter to which it is applied. Neither of thefe conjectures
is ricrht. The motive force changes as the motion acce¬
lerates, and in the firit cafe, it moves two balls and m
the fecond it moves four. The motive force decreaies
fimilarly in both motions. When thefe things are con-
fidered, we learn by articles 20 2 and 207, that the mo¬
tions will be precifely what we obferve.
Of Deflecting Forces, in General.
160. It was obferved, in art. 71, that a curvilineal
motion is a cafe of W defledlion. Therefore when
fuch motions are obferved, we know that the body is
under the influence of iome natural force, act¬
ing in a direction which croffes that of the motion m
every point. We muft infer the magnitude and direc¬
tion of this deflecting force by the magnitude and di¬
rection of the obferved defleCtion. 1 herefore, all that
is affirmed concerning detieftions in the 71 ft and fubfe-
quent articles, may be affirmed concerning defleamg
forces. It follows, from what has been eltabhflied con¬
cerning the aCtion of accelerating forces,. that no force
can produce a finite change of velocity m an inftant.
Now, a defleCtion is a compofition of a motion already
exifting with a motion accelerated from reft by inlenli-
ble degrees. Suppofing the deflecting force of invaria¬
ble direction and*intenfity, the deflection^ is the compo¬
fition of a motion having a finite velocity with a mo¬
tion uniformly accelerated from reft. I herefore the
linear deflection from the rectilineal motion muft m-
creafe by infenfible degrees. The curvilmea^ path,
therefore, muft have the line of undeflefted motion for
its tangent. To fuppofe any finite angle contained be¬
tween them would be to fuppofe a polygonal motion,
and a fubfultory defleCtion.
Therefore no finite change of direction can be produced
bn a deflecting force in an infant. .
170. The molt general and ufeful propofition on
this fubieCt is the following, founded on art. 75.
The forces by which bodies arc deflected from the tan¬
gents in the different points of their curvilineal paths are
proportional to the fquares of the velocities in thofe points,
direBly, and inverfehj to the defleBtve chords of the equi-
curve circles in the fame points. We may ftill exprefs
the propofition by the fame fymbol
where/means the intenfity of the deflefting force.
171. We may alfo retain the meaning of the propofi¬
tion exprefled in article 76, where it is {hewn that the
actual linear defleftion from the tangent is the third
proportional to the defleftive chord and the arch defcrib-
ed in a very fmall moment. For it was demonftrated
in that article (fee fig. .8.) that EZ ■■ BC= BC : BO.
We fee alfo that B b, the double of BO, is the rnea-
fure of the velocity, generated by the uniform acfion
of the deflefting force, during the motion m the arch
EC of the curve.
172. The art. 77. alfo furnifhes a propofition of fre¬
quent and important ufe, viz. .
The velocity in any point of a curvilinear motion is
that which the defleBing force in that point would gene-
DYNAMICS. 495
rate in the body by uniformly impelling it along theO^mg
fourth part of the defleBive chord of the equicurve cir-
cle.
Remark.
173. The propofitions now given proceed on the fuf-
pofition that, when the points A and C of fig. 18, al¬
ter continually approaching to B, at laft coalerne with
it, the laft circle which is defcribed through thele thiee
points has the fame curvature which the path has in B.
It is proper to render this mode of folving thefe ques¬
tions more plain and palpable.
If ABCD (fig. 35.) be a material curve or mould,
and a thread be made fail to it at D, this thread ma>
be lapped on the convexity of this curve, till its extre¬
mity meets it in A. Let the thread be now unlappe*
or evolved from the curve, keeping it always tight.
It is plain that its extremity A will defcribe another
curve line Abe. All curves, in which the curvature
is neither infinitely great nor infinitely fmall, may be
thus defcribed by a thread evolved from a proper
curve. The properties of the curve Abe being known,
Mr Huyghens (the author of this way of generating
curve lines) has ftiewn how to conftruCt the evolved
curve ABO wThich will produce it.
From this genefis of curves we may infer, ill, that
the detached portion of the thread is always a tangent
to the curve ABC } 2dly, that when this is in any fi-
tuation B b, it is perpendicular to the tangent of the
curve Abe in the point b, and that it is, at the fame
time, deferibing an element of that curve, and an ele¬
ment of a circle abr., whofe momentary centie is B,
and which has B b for its radius. ^ie Par^
£ A of the curve, being defcribed with radii growing
continually fhorter, is more incurvated. than the circle
b u, which has B b for its conftant radius. For fimilar
reafons the arch b c oi the curve Abe is lefs. incurva-
ted than the circle u. b x. 4thly, lhat the circle a. b y-
has the fame curvature that the curve has in b, or is an
equicurve circle. B is the radius, and B the cen¬
tre of curvature in the point b.
ABC is the curva evoluta or the evolute.
AZ'C is fometimes called the involute of ABC, and
fometimes its evolutrix.
174. By this way of deferibing curve lines, we fee
clearly that a body, when palling through the point b of
the curve A.b c may be confidered as in the fame ftate,
in that inftant, as in palling through the fame point b
of the circle ub*.-, and the ultimate ratio of the de-
fle&ions in both is that of equality, and they may be
ufed indiferiminately.
The chief difficulty in the application of the preced¬
ing theorems to the curvilineal motions which are ob¬
ferved in the fpontaneous phenomena of nature, is in af-
certaining the direftion of the defleaion in every point
of a curvilineal motion. Fortunately^ however, the
moft important cafes, namely thofe motions, where the-
deflefting forces are always dire&ed to a fixed point,
afford a very accurate method. Such forces are called
by the general name of
Central Forces.
j 7 If bodies defcribe circles with a uniform motion,,
the defleBing forces arc always direBed to the centres of
49^ D Y N A
W MoVmg the circks, am! are proportional to the fquare of the ve-
. Fo^ces- , loci ties, direBhj, and to their di/iances from the centre,
* inverfely.
I or, fince their motion in the circumference is uni¬
form, the areas formed by lines draw from the centre
are as the times, and therefore (72.) the deflections,
and the deflecting forces (164.) are directed to the cen¬
tre. Therefore, the defleCtive chord is, in this cafe,
the diameter of the circle, or twice the diltance of the
body from the centre. Therefore, if we call the diltance
from the centre d, we have f ~
176. Thefe forces are alfo as the difances, direRhj,
and as the fquare of the time of a revolution, inverfely.
For the time of a revolution (which may be called
the periodic time) is as the circumference, and there¬
fore as the diltance, direCtly, and as the velocity, in¬
verfely. Therefore / and v and v1 rr
vx . d
and -7 — i.
d * d
177. Thefe forces are alfo as the di/lances, and the
fquare of the angular velocity, jointly.
For, in every uniform circular motion, the angular
velocity is inverfely as the periodic time. Therefore,
calling the angular velocity a, a' :£= and jxd=. d a1,
and therefore f ~ d az.
178. The periodic time is to the time of falling along
half the radius by the uniform a£lion of the centripetal
force in the circumference, as the circumference of a cir¬
cle is to the radius.
For, in the time of falling through half the radius,
the body would defcribe an arch equal to the radius
(37-—6.) becaufe the velocity acquired by this fall is
equal to the velocity in the circumference (167.) The
periodic time is to the time of defcribing that arch as
the circumference to the arch, that is, as the circum¬
ference is to the radius.
179. When a body deferibes a curve which is all in
one plane, and a point is fo fituated in that plane, that
a line drawn from it to the body defcribes round that
point areas proportional to the times, the defetiing force
is always dire Bed to that point (72.)
I 8a. Converfely. If a body is defleBed by a force
always direBed to a fixed point, it will defcribe a curve
line lying in one plane which pafies through that point,
and the line joining it with the centre of forces will de¬
fcribe areas proportional to the times (73.)
The line joining the body with the centre is called
the RADIUS VECTOR. The deflecting force is called
CENTRIPETAL, or attractive, if its direCHon be al¬
ways toward that centre. It is called repulsive, or
centrifugal, if it be direCted outwards from the cen¬
tre. In the firft cafe, the curve will have its concavity
toward the centre, but, in the fecond cafe, it will be
convex toward the centre. The force which urges a
piece of iron towards a magnet is centripetal, and that
which caufes two electrical bodies to feparate is centri¬
fugal.
181. The force by which a body may be made to de¬
fcribe circles round the centre of forces, with the angu¬
lar velocities which it has in the different points of its
MIC S. Part JX;
curvilmealpath, are inverfely as the rubes of its difiances Of Moving
from the centre of forces. For the centripetal force in Forces,
circular motions is proportional to da* fiyil) But '
when the defle&ions (and confequently the forces) are
direfted to a centre, we have a ~ ~ f7C.'V and
• tt1
a ~ therefore d a1 7=. d x -q-, dpi —, therefore
Phis force is often called centrifugal, the centrifugal
force of circular motion, and it is conceived as always
adding ii; every cafe of curvilineal motion, and to adit
in oppofition to the centripetal force which produces
that motion. But this is inaccurate. We fuppofe thisf
force, merely becaufe we mull employ a centripetal
force, juft as we fuppofe a refilling vrs inertiae, becaufe
we mult employ force to move a body.
182. If a body defcribe a curve line ABC by means
of a centripetal (fig. 36.) force direBed to S, and vary¬
ing according to fame proportion of the difiances from it,
and if another body be impelled toward S in the firaight
line a b S by the fame force, and if the two bodies have
the fame velocity in any points A and a which are equi-
dfiant from S, they will have equal velocities in any
other two points C and c, which are alfo equidifiant
from S.
Defcribe round S, with the diftance SA, the circu¬
lar arch A a, which will pafs through the equidiftant
point a. Defcribe another arch B b, cutting off a fmall
arc AB of the curve, and alfo cutting AS in D. Draw
DE perpendicular to the curve.
The diftances AS and a S being equal, the centri¬
petal forces are alfo equal, and may be reprefented by'
the equal lines AD and a b. The velocities at A and
a being equal, the times of defcribing AB and a b will
be as the fpaces (14O The force o ^ is wholly em¬
ployed in accelerating the reftilineal motion along a S.
But the force AD, being tranfverfe or oblique to the
motion along AB, is not wholly employed in thus ac¬
celerating the motion. It is equivalent to the two
forces AE and ED, of which ED, being perpendi¬
cular to AB, neither promotes nor oppofes it, but in-
curvates the motion. The accelerating force in A
therefore is AE. It wras fhewn, in art. 48, that the
change of velocity is as the force and as the time
jointly, and therefore it is as AE X AB. For the fame
reafon, the change of the velocity at c is as £ x «
or a b1. But, as the angle ADB is a right angle, as
alfo AED, we have AE : ADr=AD : AB, and AE
X ABrr ADZ, zzab7'. Therefore, the increments of
velocity acquired along AB and a b are equal. But
the velocities at A and a wrere equal. Therefore the
velocities at B and b are alfo equal. The fame thing
may be faid of every fubfequent increafe of velocity^,
while moving along BC and b c; and therefore the ve¬
locities at C and c are equal.
The fame thing holds, when the deflecting force is
direCted in lines parallel to a S, as if to a point S' infi¬
nitely diftant, the one body defcribing the curve line
VA'B', while the other defcribes the ftraight line VS.
183. The propofitions in art 73. and 74. are alfo true
in curvilineal motions by means of central forces.
1
When
Part II.
Of Moving
Forces.
D Y N A
When the path of the motion is a line, returning in¬
to itfelf, like a circle or oval) it is called an orbit j
othenvife it is called a TRAJECTORY* .
The time of a complete revolution round an orbit is
called the periodic time* ^
184. The formula /== “ krves for difcovering the
law of variation of the central force by which a body
defcribes the different portions of its curvilmcal path J
and the formula/^: ferves for comparing the forces
by which different bodies defcribe their refpe&ive orbits.
l8j. It muff always be remembered, in conformity
to art. 77. that f- ~ or/= expreffes the li¬
near deflexion from the tangent, which may be taken
2
for a meafure of the defleaing force, and that/—
0rf— 2-. arC- expreffes the velocity generated by this
force, during the defcription of the arc, or the velo¬
city which may be compared direftly with the velocity
of'the motion in the arc. The lall is the moft accu¬
rate, becaufe the velocity generated is the real change
of condition. . -
186. may defcribe, bij the a&ion of a centra
petal force, the direBion of which pafes through C
(fig. 36.), a figure VPS, which figure revokes (in its
own plane') round the centre of forces C, in tlic fiatfe
manner as it defcribes the quiefcent figure, provided that
the angular motion of the body in the orbit he to that
of the orbit itfelf in any confiant ratio, fuch as that of
m /o n. . . ,
For, if the direclion of the orbit’s motion be the
fame with that of the body moving in it, the angular
motion of the body in every point of its motion is in-
creafed in the ratio of m to n+m, and it will be in the
fame ratio in the different parts of the Orbit as before,
that is, it will be inverfely as the fqUare of the dihance
from S (75). Moreover, as the diftances from the
centre in the fimultaneous pofitions of the body, in the
quiefcent and in the revolving orbit, are the fame, the
momentary increments of the area are as the momentary
increments of the angle at the centre •, and therefore, in
both motions, the areas increafe in the conftant ratio of
m to tu-\-n (75.) Therefore the areas of the abfolute
path, produced by the compofition of the twro motions,
will Hill be proportional to the times', and therefore
(*yzl) the defledling force mull be directed to the centre
s ; or, a force fo direfted will produce this compound
motion.
187. The differences between the forces by which a
body may be made to move, in the quiefcent and in the
moveable orbit are in the inverfe triplicate ratio of the
difiances from the centre of forces.
Let VKSBV (fig. 36.) be the fixed orbit, a*d up k
b u the fame orbit moved into another pofition} and let
Vol. VII. Part II.
M I C S. . . 497
V/i n N 0 N / QV be the orbit defcribed by the body in 0rF““"n8
abfolutc fpace by the compofition of its motion m the
orbit with the motion of the orbit itfelf. If the bod)
be fuppofed to defcribe the arch VP of the fixed orbit
while the a5cis VC moves into the lituation u C, and if
the arch up be made equal to VP, then/> will be the
place of the body in the moveable orbit, and in the
compound path Vp. If the angular motion in the fix¬
ed orbit be to the motion of the moving orbit as m to
n, it is plain that the angle VCP is to VC/> as m to
Let PK and p k be two equal and very fma'J
arches of the fixed and moving orbits. PC and p c are
equal, as are alfo KC and k C, and a circle deicribe^
round C with the radius CK will pafs through k. ll
we now make VCK to VC n as m tom fin: the point
n of the circle h n will be the point of the compoun.
path, at which the body in the moving orbit arrives
w^hen the body in the fixed orbit arrives at K, and p n
is the arch of the abfolute path defcribed while PK is
defcribed in the fixed path.
In order to judge of the difference between the force
which produces the motion PK in the fixed orbit and
that which produces « in the abfolute path, it mull be
obferved that, in both cafes, the body is made to ap¬
proach the centre by the difference between CP and CK-3
This happens, becaufe the centripetal forces, in both
cafes, are greater than what would enable the body to
defcribe cifcles round C, at the dillauce CP, and with
the fame angular velocities that obtain in the two paths,
viz. the fixed orbit and the abfolute path. We Ihal!
call the one pair of forces the circular forces, and the
other the orbital. Let C and c repreient the forces
which would produce circles, with the angular veloci¬
ties wrhich obtain in the fixed and moving orbits, and
Jet O and 0 be the forces wdiich produce the orbital
motions in thefe two paths. ^
Thefe things being premifed, it is plain that 0—c is
equal to O —C, becaufe the bodies are equally brought
towards the centre by the difference between O and C
and by that between 0 and c. Therefore 0 — O is
equal to c— C (a). The difference, therefore, of the
forces which produce the motions in the fixed and mot -
ing orbits is always equal to the difference of the forces
which would produce a circular motion at the lame di-
llances, aud with the fame angular velocity. But the
forces which produce circular motions, with the angular
motion that obtains in an orbit at different dillances from
the centre of forces, are as the cubes of the dillances
inverfely (17 5 0 And the twTo angular motions at the
fame dillance are in the conllant ratio of m to m n.
Therefore the forces are in a conllant ratio to each
other, and their differences are in a conllant ratio to
either of the forces. But the circular force at different
dillances is inverfely as the cube of the dillance (22l).
Therefore the difference of them in the fixed and move-
able orbits is in the fame proportion. But the diffe¬
rence of the orbital forces is equal to that of the cir¬
cular. Therefore, finally, the difference of the centri-
2 R petal
CO co
(a) Forkt Ac, AO, Ac, AC reprefent the four forces 0, O, c, and C. By what has been faid, we find
that oc—OC. To each of thefe add Or, and then it is plain that 0 Ot=cC, that is, that the difference of the
circular forces c and C is equal to that of the orbital forces 0 and O.
498
D Y N A M I C S.
Part IT.
Ot Moving petal forces by which a body may be retained in a fixed
^ Forces. ^ orbit, and in the fame orbit moving as determined in
article 180, is always in the inverfe triplicate ratio of
the dillances from the centre of forces.
In this example, the motion of the body in the or¬
bit is in the fame direction with that of the orbit, and
the force to be joined with that in the fixed orbit is al¬
ways additive. Had the orbit moved in the oppofite
direction, the force to be joined would have been fub-
tra&ive, unlefs the retrograde motion of the orbit ex¬
ceeded twice the angidar motion of the body. But in
all cafes, the reafoning is fimilar.
188. Thus we have confidered the motions of bodies
influenced by forces diredled to a fixed point. But wre
cannot conceive a mere mathematical point of fpace as
the caufe or occafion of any fuch exertion of forces.
Such relations are obferved only between exifling bo¬
dies or maffes of matter. The propofitions wdiich have
been demonflrated may be true in relation to bodies
placed in thole fixed points. That continual tendency
towards a centre, which produces an equable deferip-
t ion of areas round it, becomes intelligible, if we fup-
pofe fame body placed in the centre of forces, attraff-
ing the revolving body. Accordingly, we fee very re'-’
markable examples of fuch tendencies towards a central
body in the motions of the planets round the fun, and
of the fatellites round the primary planet.
But, iince it is a univerfal fact that all the relations
between bodies are mutual, we are obliged to fuppofe
that whatever force inclines the revolving body towards
the body placed in the centre of forces, an equal force
(from whatever fource it is derived) inclines the central
body toward the revolving body, and therefore it can¬
not remain at reft, but mult move towards it. The no¬
tion of a fixed centre of forces is thus taken away a-
gain, and we leem to have demonftrated propofitions
inapplicable to any thing in nature. But more atten¬
tive confideration will (hew us that our propofitions are
moft ftridftly applicable to the phenomena of nature.
189. For, in the firft place, the motion of the com¬
mon centre of pofition of two, or of any number of
bodies, is not affefted by their mutual aftions. Thefe,
being equal and oppofite, produce equal and oppofite
motions, or changes of motion. In this cafe, it follows
from art. 115. that the ftate of the common centre is
not affefted by them..
190. Now, fuppofe two bodies S and P, fituated at
the extremities of the line SP (fig. 37.) Their centre
«f pofition is in a point C, dividing their diftance in fuch
a manner that SC is to CP as the number of material
atoms in P to the number in S or SC : PC=:P : S.
Suppofe the mutual forces to be centripetal. Then, be¬
ing equal, exerted between every atom of the one, and
every particle of the other, the vis motrix may be ex-
preffed by P x S. This mull produce equal quantities
of motion in each of the bodies, and therefore muft
produce velocities inverfely as the quantities of matter.
In any given portion of time, therefore, the bodies will
move towards each other, toj-and/>, and Sr wall be
to P/ as P to S, that is, as SC to PC. Therefore we
fhall ftill have r C :/> C=SC PC. Their diftances
from C will;always be in the fame proportion. Alfo
we lhall have SC : SPurP : S-|-P, and r C : /> CrrP : S
+ P', and therefore SC : SPrnr C : r P. Confequent-
ly, in whatever manner the mutual forces vary by a va¬
riation of diftance from each other, they will vary in Of Moving
the fame manner by the fame variation of diftance from C. r°rce<t- J
And, Converfely, in whatever manner the forces vary by
a change of diftance from C, they vary in the fame man¬
ner by the fame change of diftance from each other.
Let us now fuppofe that when the bodies are at S
and P, equal moving forces are applied to each in the
oppofite directions SA and PB. Did they not attract
each other at all, they would, at the end of fome fmall
portion of time, be found in the points A and B of a
ftraight line drawn through C, becaufe they will move
with equal quantities of motion, or with velocities SA
and PB inverfely as their quantities of matter. There¬
fore SA : PB—SC : PC, and A, C, and B are in a
ftraight line. But let them now attracl, when impelled
from S and P. Being equally attracted toward each
other, they will deferibe curve lines Sff and P/>, fo
that their deflections A a and B b are as SC and PC ^
and we lhall have a C : b C—SC : PC. As this is true
of every part of the curve, it follows that they de¬
feribe limilar curves round C, which remains in its ori¬
ginal place.
Lajlly, If the motion of P be confidered by an ob-
ferver placed in S, unconfcious of its motion, fmee he
judges of the motion of P only by its change of direc¬
tion and of diftance, we may make a figure which will
perfectly reprefent this motion. Draw the line EF e-
qual and parallel to PS, and EG equal and parallel to
nb. Do this for every point of the curve Stf and PA
We ftiall then form a curve EG fimilar to the curves
S a and P Z», having the homologous lines equal to the
fum of the homologous lines of thefe two curves. Thus
the bodies will deferibe round each other curve lines
which are fimilar and equal (lineally) to the lines which
they deferibe round their common centre by the fame
forces. They may appear to deferibe areas proportional
to the times round each other; and they really deferibe
areas proportional to the times round their common
centre of pofition, and the forces, which really relate
to the body which is fuppofed to be central, have the
fame mathematical relation to their common centre.
Thus it appears that the mechanical inferences,
drawn from a fuppofed relation to a mere point of fpace,
are true in the real relations to the fuppofed central
body, although it is not fixed in one place.
191. The time of deferibing any arch FG of the
curve deferibed round the other body at reft in a centre
of forces (where we may fuppofe it forcibly withheld from
moving) is to the time of deferibing the fimilar arch P b
round the common centre of pofition in the fubduplicate
ratio of S + P to S, that is, in the ratio of ^Sfl-P to
v/S. For the forces being the fame in both motions,
the fpaces deferibed by their fimilar actions, that is, their
defleftions from the tangent, are as the fquares of the
times T and t (204). That is, HG : BZ'irT2 : t\ and
T : t— VHG : \/Bl, = a/B+P : VS.
Hence it follows that the two bodies S and P are
moved in the fame -way as if they did not aift on each
other, but were both atted upon by a third body, placed
in their common centre C, and a (ling with the fam.y-'
forces on each ; and the law of variation of the forces
by a change of diftance from each other, and d'om this
third body, is the fame.
192. If a body P (fig. 38.) rev*-V£ around another
/
f
%
X) YJNVA MIC s.
Plate CPXXA'y
r
v - .
 1
1 -
H \^T\
/ \
W- 
^\\/ \
\ m
\ V\
q Xk y
\ 'N'
\ ^
/ /
p / /
k c
>///
] \\\ ^
W v\
/ / //X
L 7X\ \\
/  
\ e\ ^
q y yr z1
c \
p
>
H /
K
DYNAMIC S
Hate C'D XXXVJ
r/./ls/ &l-
Part II. D Y N A
Of Moving body 5, by tlie action of a central force, while S moves
. Forc<-s. in any path ASB, P will continue to defcribe areas
y- "" proportional to the times round S, if every particle in
P be affe&ed by the fame accelerating force that adts,
in that inftant, on every particle in S. For, fuch ac¬
tion will compound the fame motions Pp and S r with
the motions of S and P, whatever they are j and it
was fhown in art. 69. that fuch compolition does not
affedt their relative motions. This is another way of
making a body defcribe the fame orbit in motion which
it defcribes while the orbit is fixed (186).
M I C S. - • 499
Such is the view of the abilracl doctrines of motion Of Moving
and of moving forces which ive propofed to lay before , *orccS- .
our readers. Thofe who have heard the excellent lec¬
tures of the late Profeffor Robifon of the univerlity of
Edinburgh will probably fee that v.Te have availed our-
felves of his valuable inti ructions *, and the learned
reader will readily perceive that we have enriched our
treatife with much important matter by borrowing free -
ly from the writings of the fame diftinguilhed philofo-
pher.
Erratum in Dynamics.—Line 10th from the bottetn. Col. if, For fig, 1. rend fig, 1. Plate CLXXXIV,
C
D Y N
Dynanome- DYNANOMETER, an inftrument for afcertaiin
ter. ing the relative itrength of men and animals. Of an
lv"" v mftrument of this kind, invented by Regnier, and of
which a defeription is given in vol. ii. Jour, de CEcole
Pobjtechniijue, the author thus fpeaks. “ Some import¬
ant knowledge, fays he, might be acquired, had w'e
the eafy means of afeertaining, in a comparative man¬
ner, our relative ftrengths at the different periods of
life, and in different ftates of health. Buffon and Gue-
neau, who had fome excellent ideas on this fubjeft, re-
quefted me to endeavour to invent a portable machine,
which, by an eafy and fimple mechanifm, might con-
duft to a folution of this quell ion, on which they were
then engaged. Thefe philofophers were acquainted
with that invented by Graham, and improved by Dr
Defaguliers, at London ; but this machine, conftrucl-
ed of wooden-work, was tpo bulky and heavy to be
portable ; and, befides, to make experiments on the
different parts of the body, feveral machines were ne-
celfary, each fuited to the part required to be tried.
They were acquainted alfo with the dynanometer of
Citizen Leroy of the Academy of Sciences at Paris.
It confiited of a metal tube 10 or 12 inches in length,
placed vertically on a foot like that of a candleltick,
and containing in the infide a fpiral fpring, having
above it a graduated lhank terminating in a globe, This
fhank, together with the fpring, funk into the tube in
proportion to the w'eight ailing upon it, and thus point¬
ed out, in degrees, the llrength of the perfon who
Lreffed on the ball with his hand.
This inftrument, though ingenious, did not appear
lufticient however to Buffon and Gueneau 5 for they
wilhed not merely to afeertain the mufcular force of a
finger or hand, but to eftimate that of each limb fepa-
rately, and of all the parts of the body. I lhall not
here give an account of the attempts I made to fulfil
the wilhes of thefe trvo philofophers, but only obferve,
that in the courfe of my experiments I had reafon to be
convinced that the conftruclion of the inftrument was
not fo eafy as might have been expeiled. Befides the
ufe which an enlightened naturalift may make of this
machine, it may be poflible to apply it to many other
important purpofes. For example, it may be employ¬
ed with advantage to determine the ftrength of draught
cattle *, and, above all, to try that of horfes, and com¬
pare it with the ftrength of other animals. It may
D Y E
ferve to make known how far the afliftancfe of well- Dynafty,
conftrutfted wheels may favour the movement of a car Dyrra-
riage, and what is its vis inertia: in proportion to the .
load. We might appreciate by it, allb, what refiltance
the Hope of a mountain oppofes to a carriage, and be
able to judge whether a carriage is fuftkiently loaded in
proportion to the number of horfes that are to be yoked
to it. In the arts, it may be applied to machines of
which we with to afeertain the relVftance, and when
we are defirous to calculate the moving force that ought
to be adapted to them. It may ferve, alfo, as a Ro¬
man balance to weigh burdens, In Ihort, nothing
would be more eafy than to convert it into an anemo¬
meter, to difeover the abfolute force of the wind, by
fitting to it a frame of a determined fize filled up with
wax-cloth j and it would not be impoflible to afeertain
by this machine the recoil of fire-armsj and confequent-
ly the ftrength of gun-powder.
This dynanometer, in its form and fize, has a near
refemblance to a common graphometer. It confifts of
a fpring twelve inches in length, bent into the form of
an ellipfis i from the middle of which arifes a femicir-
cular piece of brafs, having engraved upon it the dif¬
ferent degrees that exprefs a force of the power acting
on the fpring. The W'hole of this machine, which
weighs only two pounds and a half, oppofes, however,
more refiftance than may be neceffary to determine the
action of the ftrongeft and moft robuft horfe,” For a
fuller defeription, fee Phil. Mag. yol. i.
. DYNASTY, among ancient hiftorians, fignifies &
race or fuccetlion of kings of the fame line or family.
Such were the dynafties of Egypt. The wwd is form¬
ed from the Greek dvretfax of Swotum, to be powerful^
or king.
The Egyptians reckon 30 dynafties within the fpace
of 36,5 25 years; but the generality of chronologers
look upon them as fabulous. And it is very certain,
that thefe dynafties are not continually fucceftive, but
collateral.
DYRRACHIUM, in Ancient Geography, a town
Cn the coaft of Illyricum, before called Epidamnum, or
Epidamniis, an inaufpicious name, changed by the Ro¬
mans to Dyrrachium ; *a name taken from the peninfula
on which it flood. Originally built by the Corcyreans.
A Roman colony (Pliny). A town famous in ftory its
port anfwered to that of Brundufium, and the paffage
3 R 2 between
33 Y S [ 5oo ] D Y S
between both was very ready and expeditious. It was
alfo a very famous mart for the people living on the
Adriatic j and the free admiflion of itrangers contri¬
buted much to its increafe : A contrail to the condudt
of the Apollonians j who, in imitation of the Spartans,
difcouraged ftrangers from fettling among them.
DYSriE, in Mythology, inferior goddefles among
the Saxons, being the meffengers of the great Woden,
whofe province it was to convey the fouls of fuch as
died in battle to his abode, called Valhall, i. e. the hall
of daughter 5 where they were to drink with him and
their other gods cerevijia, or a kind of malt liquor, in
the Ikulls of their enemies. The Dyfce conveyed thofe
who died a natural death to Hela, the goddefs of hell,
where they were tormented with hunger, thirll, and
every kind of evil.
DYSCRASY, among phyficians, denotes an ill ha¬
bit or Hate of the humours, as in the fcurvy, jaundice,
&c.
DYSENTERY, in Medicine, a diarrhoea or flux,
wherein the ftools are mixed with blood, and the bowels
miferably tormented writh gripes. See Medicine
Index.
DYSENTERIC FEVER. Ibid. Djfenteric
DYSERT, a parliament town of Scotland, in the il
county of Fife, fituated on the northern fhore of the . yvour‘
frith of Forth, about 11 miles north of Edinburgh.
DYSOREXY, among phyficians, denotes a want
of appetite, proceeding from a weakly ftomach.
DYSPEPSY, a difliculty of digeftion.
DYSPNOEA, a difficulty of breathing, ufually cal¬
led aflhma. See Medicine Index.
DYSURY, in Medicine, a difficulty of making
water, attended with a fenfation of heat and pain. See
Medicine Index.
DYTISCUS, water-beetle. See Entomology
Index.
DYVOUR, in Scots Lavs; otherwife Bare-man;
A perfon who, being involved in debt, and unable to
pay the fame,—for avoiding imprifonment and other
pains, makes ceffion of his effedls in favour of his cre¬
ditors $ and does his devoir and duty to them, proclaim¬
ing himfelf bare-man and indigent, and becoming debt
bound to them of all that he has. The WT>rd is ufed
in the fame fenfe as Bankrupt : fee that article; and
Law Index.
E
#
’TC* THE fecond vowel, and fifth letter of the alpha-
bet. The letter E is molt evidently derived from
the old charadler 3 in the ancient Hebrew and Phoe¬
nician alphabets, inverted by the Greeks to this pofi-
fition E, and not from the Hebrew He rr. From the
fame origin is alfo derived the Saxon e, which is the
firit letter in their alphabet that differs from the Latin
one. It is formed by a narrower opening of the la¬
rynx than the letter A 5 but the other parts of the
mouth are uled nearly in the fame manner as in that
letter.
It has a long and fhort found in molt languages.
The ffiort found is audible in bed, fret, den, and other
words ending in confonants : its long found is produ¬
ced by a final e, or an e at the end of words ; as in
glebe, here, hire, fcene, fphere, interfere, revere, fin-
cere, &.c. in moll of which it founds like ee; as alfo in
fome others by coming after i, as in believe, chief, grief,
reprieve, &c. and fometimes this long found is expreiled
by ee, as in bleed, beer, creed, &c. Sometimes the fi¬
nal e is filent, and only ferves to lengthen the found of
the preceding vowel, as in rag, rage, fiag, fiage, hug,
huge, &zc. The found of e is obfcure in the following
words oxen, heaven, boitnden, fire, majfacre, maugre,
&c.
The Greeks have their long and ffiort e which they
call epfilon and eta. The French have at leaf! fix kinds
of e’s: the Latins have likewife a long and ffiort e;
they alfo write e inftead of a, as dicem for dicam. Sic.
and this is no doubt the reafon wffiy a is fo often
changed into e in the preter tenfe, as ago, egi; facio,
feci, &c.
As a numeral, E Hands for 250, according to the Kachan!,
verfe, —-v—-J
E, quoque ducentos et quinquaginta tenebit.
In mufic it denotes the tone e-la-mi. In the Calen¬
dar it is the fifth of the dominical letters. And in fea
charts it diftinguiffies all the eafterly points : thus,
E alone denotes Eaft j and E. by S. and E. by N. Eaft
by South, and Eaft by North.
EACHARD, John, an Engliffi divine of great
learning and wit in the 17th century, bred at Cam¬
bridge, author (in 1670) of The Grounds and Qccafions
of the Contempt of the Clergy and Religion inquired into.
In 1675 he was chofen mafter of Catharine-hail upon
the deceafe of Dr John Lightfoot; and the year fol¬
lowing was created D. D. by royal mandate. He died
in 1696.
Eachard, Laurence, an eminent Engliffi hiftorian
of the 18th century, nearly related to Dr John Eachard..
He was the fon of a clergyman, who, by the death of
his elder brother, became mafter of a good eftate in..
Suffolk. He was educated in the univerlity of Cam¬
bridge, entered into holy orders, and was prefented to
the living of Welton and Elkington in Lincolnlhire',
wffiere he fpent above 20 years of his life, and diftin-
guiffied himfelf by his writings, efpecially his Hiitory
of England, which was attacked by Dr Edmund Ca-
lamy and by Mr John Oldmixon. His “ General Ec-
clefiaftical Hiftory from the Nativity of Chrift to the
firft Eftablilhment of Chriftianity by Human Laws un¬
der the emperor Conftantine the Great,” has paffed
through feveral editions* He was inltalkd archdeacon
E A D
Eadmems. of Stowe and prebend of Lincoln in 171 2
’ in I7S°* , , • -c-
EADMERUS, an efteemed hiftonan, was an Rng-
lifhman j but his parents, and the particular time and
place of his nativity, are not known. He received a
learned education, and very early difcovered a tafte
for hiftory, by recording every remarkable event that
came to his knowledge. Being a monk in the cathe¬
dral of Canterbury, he had the happinefs to become
the bofom friend and infeparable companion of two
archbiihops of that fee, St Anfelm and his fucceifor
Ralph. To the former of thefe he was appointed
fpiritual dire£tor by the pope } and that prelate would
do nothing wTithout his permiffion. In the year 1120,
he was fent for by King Alexander I. of Scotland, to
be raifed to the primacy of that kingdom •, and hav¬
ing obtained leave of King Henry and the arch-
bifhop of Canterbury, he departed for Scotland, where
he was kindly received by the king •, and on the third
day after his arrival, he was elefted bilhop of St An¬
drew’s with rmwh unanimity. But on the day after
his election, an unfortunate difpute arofe between the
king and him, in a private conference about his con-
fecration. Eadmerus having been a conftant compa¬
nion of the late and of the prefent archbifhop of Can¬
terbury, was a violent ftickler for the prerogatives of
that fee. He therefore told the king, that he was
determined to be confecrated by none but the archbi-
ihop of Canterbury, who he believed to be the pri¬
mate of all Britain. Alexander, who was. a fierce
prince, and fupported the independency of his crown
and kingdom with great fpirit, was fo much offended,
that he broke off the conference in a violent paffion,
declaring, that the fee of Canterbury had no pre-emi-
nency over that of St Andrew’s. This breach be-
tween the king and the bifhop-eleff became daily
wider, till at length Eadmerus, defpairing of recover¬
ing the royal favour, fent his paftoral ring to the
king, and laid his paftoral ftaff on the high altar,
from whence he had taken it, and abandoning his bi-
fhopric returned to England. He wras kindly ic-
ceived by the archbiftiop and clergy of Canterbury,
though they difapproved of his ftiffnefs, and thought
him too hafty in forfaking the honourable ftation to
which he had been called. Nor was it long before-
Eadmerus became fenfible of his error, and defirous
of corre&ing it. With this view he ivrote a long
fubmiflive letter to the king of Scotland, entreating
his leave to return to his bifhopric, promifing compli¬
ance with his royal pleafure in every thing refpeQmg
his confecration, which was accompanied by an epiftle.
to the fame purpofe from the archbiftiop. Tnefe let¬
ters, however, wdiich wrere written A. D. II2.2, did
not produce the defired effeft. But Eadmerus is moft
worthy of the grateful remembrance of pofterity for
his hiftorical works, particularly for his excellent hiftory
of the affairs of England in his own time, from A. D.'
1066 to A. D. 1122 ; in which he hath inferted many
original papers, and preferved many important facts,
that are nowhere' elfe to be found. .This work hath
been highly commended, both by ancient and modern
writers, for its authenticity, as well as for regularity of
compofition and purity of ftyle. It is indeed more
free from legendary tales than any other wrork Oi
this period} and.it is impoflible to perufe it with a.-
[ 501 ] E A G , . r
He died tention, without conceiving a favourable opinion 0
the learning, good fenfe, fincenty, and candour of its
author. r ,
EAGLE. See Falco, Ornithology Index.
Eagle, in Heraldry, is accounted one of the molt
noble bearings in armoury and, according to the learn¬
ed in this fcience, ought to be given to none but iuch
Eagle.
as greatly excel in the virtues of generofity and cou¬
rage, or for having done Angular femces to their fove-
reigns ; in which cafes they may be allowed a whole
eagle, or an eagle naiifant, or only the head or. other
parts thereof, as may be moft agreeable to their ex-
P The eagle has been borne, by w^ay of enfign or ftand-
ard, by feveral nations. The firft who feem to have
affumed the eagle are the Perfians •, according to the
teftimony of Xenophon. Afterwards, it was taken by
the Romans ; who, after a great variety of ftandards,
at length fixed on the eagle, in the fecond year of the
confulate of C. Marius : till that time, they uled in¬
differently wolves, leopards, and eagles, according to
the humour of the commander.
The Roman eagles, it muft be obferved, were, not
painted on a cloth or flag j but were figures m relievo,
of filver or gold, borne on the tops of pikes ; the w ings
being difplayed, and frequently a thunderbolt in their
talons. Under the eagle on the pike, were piled buck¬
lers, and fometimes crowms. Thus much we learn from
the medals. t .
Conftantine is faid to have firft introduced the eagle
with two heads, to intimate, that though the empire
feemed divided, it was yet only one body. Others
fay, that it was Charlemagne who. refumed the eagle as
the Roman enfign, and added to it a fecond head j but
that opinion is deftroyed, by an eagle with two heads,
noted by Lipfius, on the Antonine column •, as alio
by the eagle’s only having one head on the feal of the
golden bull of the emperor Charles IV. The con-
jetfture, therefore,., of F. Meneftrier appears more pro¬
bable, who maintains, that as the emperors of the Ealt,
when there wrere twro on the throne at the fame tune,
ftruck their coins with the .impreftion of acrois, with
a double traverfe, which each of them held m one
hand, as being the fymbol of the Chriftians j the like
they did with the eagle in their enfigns } and inftead.
of- doubling their eagles, they, joined them toge¬
ther, and reprefented them with two heads.^ In
which they were followed by the, emperors of the
Weft. . _ . _ _ r
F. Papebroche wifhes that this conjecture of Menei-
trier were confirmed by ancient coins ; without which,
he rather inclines to think the-ufe of the eagle with
two heads to be merely arbitrary j though he -grants
it probable, that it was firft introduced -on occaiion ol
two emperors on the fame throne... _
The eagle on medals, according to M. Spanheim,
is a fymbol of divinity and providence j and, accord¬
ing to all other antiquaries, of empire. The princes
on whofe medals it is moft ufually found, are the Pto¬
lemies and the Seleucides of Syria.. An eagle with
the wprd CONSECRATIO, expreffes the apotheons of an 1
emperor. . , ,
Eagles, a name found very frequently m the an¬
cient hiftories of Ireland, and ufed to exprefs a fort of
bafe money that was current, in that kingdom m the
E A L
'!rft >‘“rs of of Edward I. that is, about the*
Ealderman.^,1;2?;; , 1 here were, befides the eagles, lionines,
t 502 ]
EAR
 , roiades, and many other coins of the fame fort
named according to the figures they were impreffed
I he current coin of the kingdom was at that time
a compofition of copper and filver, in a determined
proportion, but . thefe were fo much worfe than the
tandard proportion of that time, that they were not
mtnnfically worth quite half fo much as the others.
I hey were Imported out of France and other foreign
-rfr* ^\hen ,thls Pnnce been a few vears
taohihed on the throne, he fet up mints in Ireland
for the coming fufficient quantities of good money,
and then decned the ufe of thefe eagles, and other the
Ime kinds of bafe coins, and made it death, with con-
.cation of effeas, to import any more of them into
the kingdom.
Eacee, in 4/Ironomrj, is a conftellation of the
northern hemifphere having its right iving contiguous
vO the equinoctial. See Aimjila.
. 1 her.e are alfo ^ree Several fiars, particularly deno¬
minated among the Arab aftronomers, nafr, i. e.
Mail, the “ eagle of Cano-
1 , called. Moftarehjemen, the itar of Arabia Felix
oyer which it jsfuppofed to prefide •, the fecond, nafr
althoir the “flying eagle;” and the third, nafr a L
*i'cke, the reibng eagle.” J
JV/uie F^GLF, a Pdifh order of knighthood, in-
ituted m .1325 by Uladillaus V. on marrying his fon
thuani'a 1 * daUghter of the great duke of Li-
Ihe knights, of this order were diftinguiflied by a
go d chain, which they wore on the ftomach, whereon
Aung a filver eagle crowned.
Black Eagle, \ns a like order, inflituted in 1701
king of'pmfl” Ikandenburgh, on his being crowned
I lie knights of this order wear an orange-coloured
nbbon, to which is fufpended a black eagle.
. in ylrcluU'tture, is a figure of that bird an-
( icnt y u.ed as an attribute, or cognizance of Jupiter,
m the capital and friezes of the columns of temples
conlecrated to that god.
F-AGLE-flower. See Bai.samine.
EAGLE-Jlone, in Natural Hi/lory, is a flone by the
.reeks called antes, and by the Italian pietra d'aquila,
as being luppofed to be fometimes found in the eagle’s
nelt. It is of famous traditionary virtue, either for
forwarding or preventing the delivery of women in
labour, according as it is applied abov^ or below the
womb Matthiolus tells us, that birds of prey could
never hatch their young without it, and that they
go m fearch of it as far as the Eaft Indies. Baufch
Ms an exprefs Latin treatife on the fubieft. See
Altites. j
• EAGLET’ ^ diminutive of eagle, properly fnmify.
mg a young eagle. In heraldry, when there are fe-
JS.W?§ eS °n thC fame efcutchcon» the7 are termed
c EALDERMAN, or Ealdormam, among the
Saxons, was of like import with earl amonj the
Uanes. ^
The word was alfo ufed for an elder, fenator, or
lutehnan. Hence, at this day, we call thofe aldermen
4
who are aflociates to the chief officer in the common
council of a city or corporate town.
'EAR. See Anatomy Index.
Several naturalifts and phyfxcians have held, that
cutting off the. ear rendered perfons barren and unpro-
. > and this idle notion was what firff occafioned the
legiflators to order the ears of thieves, &c, to be cut
off, left they fliould produce their like.
The ear has its beauties, which a good painter ought
> no means to difregard ; where it is well formed, it
would be an injury to the head to be hidden. Sueto¬
nius infills, particularly, on the beauties of AugulWs
ears ; and EElian, deferibing the beauties of Afpalia,
obferves, Ihe had ftiort ears. Martial alfo ranks larec
ears among the number of the deformities.
Among the Athenians, it was a mark of nobility
to have the ears bored or perforated. And among
the Hebrews and Romans, this was a mark of fervi-
tude.
Lofs of one ear is a punifhment enacted by 5 and 6
Edw. VI. cap. 4. for fighting in a churchyard ; and
by 2 and 3 Edw. .VI. cap. 15. for combinations to raife
the price of provifions, labour, &c. if it be the third
offence, befide pillory, and perpetual infamy, or a fine
of 40I.
By a ilatute of Henry VIII. malicioufly cutting
off the ear of a perfon is made a trefpafs, for which
treble damages fliall be recovered ; and the offender is
to pay a fine of ten pounds to the king, 37 Hen.'
VIII. cap.. 6. $ 4. In the Index to the Statutes at
Large, it is faid, that this offence may be puniftied as
felonv by 22 and 23 Car. II. cap. 1. $ 7. commonly
called Coventry's adi ; but ear is not mentioned in that
ftatute.
Ear ofFifkes. See Anatomy Index.
Ear, in Mu fie, denotes a kind of internal fenfe,
whereby we perceive and judge of harmony and mufi-
cal founds. See Music.
In mufic we fe.em univerfally to acknovdedge fome-
thing like a diftindl fenfe from the external one of
nearing ; and call it a good ear. And the like dillinc-
tion we fliould probably acknowledge in other affairs,
had we got diffmft names to denote thefe powers of
perception by. Thus a greater capacity of perceiving
the beauties of painting, archite&ure, &c. is called a
fne tajle*
Ear is alfo ufed to fignify a long clufler of flowers
or feeds, produced by certain plants ; ufually called by
botanifts^/Li. The flowers and feeds of wheat, rye,
barley, &c. grow in ears. The fame holds of the*
flowers of lavender, &c. We fay the ftem of the ear,
1. e. its tube or ftraw; the knot of the ear; the lobes
or cells wherein the grains are enclofed ; the beard of
the ear, &c.
Ear-AcJi. See Medicine Index.
EARING, in the fea language, is that part of the
Dolt rope which at the four corners of tjie fail is left
open, in the lhape of a ring. The two uppermoft
parts are put over the ends of the yard arms* and fo
the fail is made faft to the yard ; and into the lower
moft carings, the iheets and tacks are feized 'or bent at
the clew.
EAR-Plck, an inferument of ivory, filver, or other
metal, fomewhat in form of a probe, for cleanfmg the
ear. The Chinefe have a variety of thefe inftruments,
with
Eaf.
Karth.
EAR [50
Ear-ring with which they are mighty fond of tickling their cars ;
but this praftice, Sir Hans Sloane obferves, muft be
j very prejudicial to fo delicate an organ, by bringing too
great a flow of humours on it.
EAR-Ring. See PENDENT.
Ear-Wux. See Anatomy Index.
EARWIG. See Foreicola, Entomoloqy index.
EARL, a Britilh title of nobility, next below a mar¬
quis, and above a vifcount.
The title is fo ancient, that its original cannot be
clearly traced out. This much, however, feems toler¬
ably certain, that amotig the Saxons they were called
caldormen, quafi elder men, fignitying the fame with
fenior or fenator among the Romans ; and alio fchire-
men, becaufe they had each of them the civil'govern¬
ment of a teveral diviiion or fhire. On the irruption
of the Danes they changed their names to eorels, which,
according to Camden, figniSed the fame in their lan¬
guage. In Latin they are called comites, (a title flrft
ufed in the empire), from being the king’s attendants;
a focietate nomen fumpferunt, reges enun tales fibi ajjbciant.
After the Norman conqueil they were for fome time
called counts, or countees, from the French ; but they
did not long retain that name themfelves, though their
flares are from thence called counties to this day. It
is now become a mere title : they having nothing to do
with the government of the county •, which is now en¬
tirely devolved on the fheriff, the earl’s deputy, or 'oice-
cotnes. In writs, comrniflions, and other formal initru-
ments, the king, when he mentions any peer of the de¬
gree of an earl, ufually Ryles him “ trulty and well be¬
loved coujin an appellation as ancient as the reign of
Henry IV. ; who being either by his wife, his mother,
or his fillers, actually related or allied to every earl in
the kingdom, artfully and conllantly acknowledged that
connexion in all his letters and other public a£ts
whence the ufage has defcended to his fucceffors, though
the reafon has long ago failed.
An earl is created by cincture of fword, mantle
of Hate put upon him by the king himfelf, a cap
and a coronet put upon his head, and a charter in his
hand.
F.ARt.-MarP)aL See Marshal.
EARNEST (ARRH^e), money advanced to bind the
parties to the performance ©f a verbal bargain. By the
civil law,, he who recedes from his bargain loles his
earned, and if the perfon who received the earned give
back, he is to return the earned double. But with us,
the perfon who gave it, is in dnflnefs obliged to abide
by his bargain ; and in <mfe he decline it, is not dif-
charged upon forfehhig his earned, but may be fued for
the whole moixT dipulated.
E ARTH, among ancient philofophers, one of the
four elements of which the whole fydem of nature was
thought to be compofed. See Element.
Earths, in Chernifirg, are fuch fabdances as have
neither tade nor fmell, are incombudible, are nearly
ihfoluble in water, and have a fpecific gravity under
5. Such are lime, barytes, &c. See Chemistry In¬
dex.
Earth, in Ajironomy and Geography, one of the
primary planets 5 being this terraqueous globe which
we inhabit.
For the adronomical fa<ds with regard to the earth,
fee Astronomy j for its geographical hidory, fee
3 ] E A S
Geography \ and for the opinions or theories of its Earthquake-
~ ~ li
formation and changes, fee Geology Index.
EARTHQUAKE. See Geology Index.
EARTH-worm. See Helminthology Index. u
EASEL pieces, among painters, fuch fmall pieces,
either portraits or landfcapesr: as are painted on the
eafel, i. e. the frame whereon the canvas is laid. They
are thus called, to didinguilh them from larger pictures
drawn on walls, ceilings, &c.
EASEMENT, in Law, a privilege or convenience
which one neighbour has of another, whether by char¬
ter or prefeription, without profit : fuch are, a way
through his lands, a fink, or the like. Thefe, in many
cafes, may be claimed.
EASING, in theTea language, fignifies the dacken-
ing a rope or the like. Thus, to eafe the bow line, or
fheet, is to let them go flacker j to eale the helm, is to
let the fliip go more large, more before the wind, or
more larboard.
E AST, one of the four cardinal points-of the world ;
being that point of the horizon where the fun is feen.
to rife when in the equinoctial.
The word eajl is Saxon. In Italy, and throughout,
the Mediterranean, the call wind is called the levante :
in Greek, and tM-nhiamt, becaufe it comes from
the fide of the fun, *7r’ kPub j in Latin eurus.
EASTER, a fedival of the Chridian church, ob-
ferved in memory of our Saviour’s refurreCtion.
The Greeks call it pafga, the Latins pafeha, a He¬
brew word fignifying/>, applied to the Jewilh feaft
of the padbver. It is called eafter in Englilh, from the-
goddefs Eodre, wordiipped by the Saxons with peculiar-
ceremonies in the month of April.
The Afiatic churches kept their eader upon the very
fame day the Jews obferved their paffover, and others
on the fird Sunday after the fird full moon in the new
year. This controverfy was determined in the council
of Nice ; when it was ordained that eader fhould be
kept upon one and the fame day, which fhoufd always
be a Sunday, in all Chridian churches in the world..
For the method of finding eader by calculation, fee
Chronology.
Eastas. IJland, an ifland in the South Sea, lying in
N- Lat. 27. 5. W..Long. 109. 46. It is thought to
have been fird difeovered in 1686 by one Davis an
Englhhman, who called it Davis's Land* It was next
vifited by Commodore Roggewein,. a Dutchman, in
x 7 2 2 j who gave it the name of Eajler IJland, and
publifhed many fabulous accounts concerning the coun¬
try and its inhabitants. It was alfo vifited by a Spa-
nidi fliip in 1770, the captain of which gave it the
name of St Carlos. The only authentic accounts of
this iiland, however, which have yet appeared, are thofe
publilhed by Captain Cook and Mr Forder, who vifit¬
ed it in the month of March 1774. According to-
thefe accounts, the ifland is about 10 or 12 leagues in
circumference, and of a triangular figure j its greated
length from north-wed to fouth-ead is about four leagues,,
and its greated breadth two. The hills are fo high, that
they may be feen at the didance of 15 or 16 leagues.
The north and cad points of the iiland are of a confi-
derable height j between them, on the fouth-ead fide,
the fhore forms an open bay, in which Captain Cook
thinks the Dutch anchored in 1722. He himfelf an¬
chored on the wed lide of the ifland, three miles north¬
ward-
Eaiter-
Ifland.
(
Iiland.
E A
ward from tlie fouth point
road with eafterly winds j but a dangerous one when
the wind blows front the contrary quarter, as the other
on the fouth-eaft fide muft be with eafterly winds i fo
that there is no good accommodation to be had for
(hipping round the whole iiland.
The iftand itielf is extremely barren •, and bears evh
dent marks not only of a volcanic origin, but of having
been not very long ago entirely ruined by an eruption.
As they approached the fouth point, Mr Forfter in¬
forms us, that they obferved the ihore to rife perpen¬
dicularly. It conlifted of broken rocks, whofe ca-
■vernous appearance, and black or ferruginous colour,
leemed to indicate that they had been thrown up by
Subterraneous fire. Two detached rocks lie about a
quarter of a mile off this point ; one of them is fingu-
lar on account of its lhape, and reprefents a huge co¬
lumn or obelilk ; and both thefe rocks were inhabited
by multitudes of fea fowls. On landing and walking
into the Country, they found the ground covered with
rocks and ftones of all fizes, which appeared to have been
expofed to a great fire, where they feemed to have ac¬
quired a black colour and porous texture. Two or three
ftirivelled fpecies of graffes grew among thefe ftones,
«nd in fome meafure foftened the defolate appearance
of the country. The farther they advanced, the more
ruinous the face of the country feemed to be. The
roads were intolerably rugged, and filled with heaps of
volcanic ftones, among which the Europeans could not
make their way but with the greateft difficulty ; but
the natives leaped from one ftone to another with fur-
prifing agility and eafe. As they went northward
along the iftand, they found the ground ftill of the fame
nature ; till at la ft they met with a rock of large black
melted lava, which feemed to contain fome iron, and
on which was neither foil nor grafs, nor any mark of
v'egetation. Notwithftanding this general barrennefs,
however, there are feveral large tradfts covered with
cultivated foil, which produces potatoes of a gold yel¬
low colour as fweet as carrots, plantains, and fugar
canes. The foil is a dry hard clay : and the inhabi¬
tants ufe the grafs which grows between the ftones
in other parts of the illand as a manure, and for pre-
ferving their vegetables when young from the heat of
the fun.
The moft remarkable curiofity belonging to this
iftand is a number of coloffal ftatues j of which, how¬
ever, very few remain entire. Thefe ftatues are placed
only on the fea coaft. On the eaft fide of the ifland
were feen the ruins of three platforms of ftone work, on
each of which had flood four of thefe large ftatues •,
but they were all fallen down from two of them, and
one from the third : they were broken or defaced
by the fall. Mr Wales meafured one that had fallen,
which was 15 feet in length, and fix broad over the
ffioulders: each ftatue had on its head a large cylin-
dric ftone of a red colour, wrought perfectly round.
Others were found that meafured near 27 feet, and up¬
wards of eight feet over the ffioulders ; and a ftill lar¬
ger one was feen (landing, the (hade of which was fuf-
ficient to (belter all the party, confiding of near 30
perfons, from the rays of the fun. The workmanflup
is rude, but not bad, nor are the features of the face
ill formed $ the ears are long, according to the diftor-
tion pradlifed in the country, and the bodies have hard-
3
S [ 504 1 E A S
I. his, he fays, is a good ly any thing of n human figure* about them.
fiow
thefe iflanders, wholly unacquainted with any mecha¬
nical power, could raife fuch ftupendous figures, and
afterwards place the large cylindrie ftones upon their
heads, is truly wonderful ! The liioft probable conjec¬
ture feems to be, that the ftone is factitious j and that
each figure Was gradually eredled, by forming a tem¬
porary platform round it, and raifing it as the wTork
advanced ; but they are at any rate very ftrong proofs
of the ingenuity and perleverance of the iflanders in the
age when they were built, as well as that the anceftors
ol the prefent race had feen better days than their de*
fcendants enjoy. Xhe water of this iftand is in general
brackiffi, there being only one well that is perfedlly
freffi, which is at the eaft end of the ifland 1 and when¬
ever the natives repair to it to flake their thirft, they*
wafti thexnfelves all over 5 and if there is a large com-*
pany, the fifft leaps into the middle of the hole, drinks,
and waffies himfelf without ceremony 5 after which
another takes his place, and fo on in fucceffion. This
cuftom was much difrelilhed by their new friends,
who flood greatly in need of this valuable article, and
did not wiffi to have it contaminated by fuch ablu¬
tions.
Ihe people are of a middle fize. In general they are
rather thin; go entirely naked $ and have punctures on
their bodies, a cuftom common to all the inhabitants of
the South Sea iflands. Their greateft Angularity is the
fize of their ears, the lobe of wffiich is ftretched Out fo that
it almoft refts on their (boulder $ and is pierced with a
very large hole, capable of admitting four or five fin¬
gers with eafe. The chief ornaments for their ears are
the white down of feathers, and rings which they wear
in the infide of the hole, made of the fugar cane, which
is very elartic, and for this purpofe is rolled up like a
watch fpring. Some were feen clothed in the fame
cloth ufed in the ifland of Otaheite, tinged of a bright
orange colour with turmeric 5 and thefe our voyagers
(uppofed to be chiefs. Their colour is a chefnut.
brown j their hair black, curling, and remarkably ftrongj
and that on the head as well as the face is cut ftiort,
I he women are fmall, and flender limbed : they have
punctures on the face, refembling the patches fome-
times ufed by European ladies ; they paint their face
all over with a reddiffi brown ruddle, and above this
they lay a fine orange colour extracted from turmeric
root; the whole is then variegated with ftreaks of white
(hell lime. But the moft furprifing circumftance of all
with regard to thefe people, is the apparent fcarcity of
women among them. The niceft calculation that could
be made, never brought the number of inhabitants in
this ifland to above 700, and of thefe the females bore
no proportion in number to the males. ILitber they
have but few females, or elfe their women were reftr^ffi-
ed from appearing during the (lay of the (hip j not-
withftanding, the men (bowed no ligns of a jealous dif-
pofition, or the women any fcruples of appearing in
public : in fa<ft, they feemed to be neither referved nor
chafte 5 and the large pointed cap which they wore
gave them the appearance of profeffed wantons. But
as all the women who were feen were liberal of their
favours, it is more than probable that all the married
and modeft ones had concealed themfelves from their
impetuous vifitants in fome infcrutable parts of the
iftand 5 and what further ft lengthens this fuppofition is,
that
Eaftsf
Ifland,
Eaves
E A U
[ 5°S ]
E B I
Eaton
tliat Leaps of ft ones were feen piled up into little hil¬
locks, which had one deep perpendicular fide, where
a hole went under ground. The ipace within, fays
Mr Forfter, could be but fmall *, and yet it is probable
that thefe cavities ferved, together with their miferable
huts, to give (belter to the people at night ; and they
may communicate with natural caverns, which are very
common in the lava currents of volcanic countries.
The few women that appeared were the moil lafcivious
of their fex perhaps that have been ever noticed in any
country 5 (hame feemed to be entirely unknown to
them.
EATON, a town of Buckinghamfhire, fituated on
the north fide of the Thames, oppofite to Windfor, and
famous for its collegiate fchool, founded by King Hen¬
ry VI. being a feminary for King’s College, Cambridge,
the fellows of which are all from this fchool. See Eton.
EAU de Carmes. See Pharmacy.
Eau de Luce, a fragrant alkaline liquor which was
fome* years ago in great repute, efpecially among the
fair fex, and of which the leading perfeflion is, that it
fhall poflefs and retain a milky opacity.
Mr Nicolfon, in the fecond number of his valuable
journal, tells us, that being informed by a philofophical
friend, that the ufual recipes for making this compound
do not fucceed, and that the ufe of mallic in it has hi¬
therto been kept a fecret, he made the following trials
to procure a good eau de luce.
One dram of the re&ified oil of amber was diflblved
in four ounces of the ftrongeft ardent fpirit of the
(hops} its fpecific gravity being .840 at 60 degrees of
Fahrenheit. A portion of the clear fpirit was poured
upon a larger quantity of fine powdered maftic than it
was judged could be taken up. This was occafionally
agitated without heat •, by which means the gum refin
was for the mod part gradually diffolved. One part of
the oily folution wras poured into a phial, and to this
was added one part of the folution of maftic. No opa¬
city or other change appeared. Four parts of ftrong
cauftic volatile alkali were then poured in, and imme¬
diately (haken. The fluid was of a denfe opaque white
colour, affording a flight ruddy tinge when the light
was feen through a thin portion of it. In a fecond
mixture, four parts of the alkali were added to one of
the folution of maftic ; it appeared of a lefs denfe and
more yellowifti white than the former mixture. More
of the gum refinous folution wTas then poured in ; but it
(till appeared lefs opaque than that mixture. It was
ruddy by tranfmitted light. The laft experiment was
repeated with the oily folution inftead of that of maftic.
The white wras much lefs denfe than either of the fore¬
going compounds, and the requifite opacity was not
given by augmenting the dofe of the oily folution. No
ruddinefs nor other remarkable appearance was feen by
tranfmitted light. Thefe mixtures were left at repofe
for two days j no feparation appeared in either of the
compounds containing maftic ; the compound, confift-
ing of the oily folution and alkali, became paler by the
feparation of a cream at the top.
It appears, therefore, that the firft of thefe three
mixtures, fubject to variation of the quantity of its in¬
gredients, and the odorant additions which may be
made, is a good eau de luce.
In a fubfequent number of the fame Journal, we have
the following recipe by one of the author’s correfpond-
Vol. VIL Part IE
ents, who had often proved its value by experience.^
“ Digeft ten or twelve grains of the whiteft pieces of Eb;011;tes
maftic, feledled for this purpofe and powdered, in
two ounces of alcohol j and, wrhen nearly diffolved,
add twenty grains of elemi. When both the refins
are diffolved, add ten or fifteen drops of redlified
oil of amber, and fifteen or twenty of effence of ber¬
gamot : (hake the whole well together, and let the
faeces fubfide. The folution will be of a pale amber
colour. It is to be added in very fmall portions to the
beft aqua atnmonice puree, until it aflumes a milky
whitenefs, (baking the phial well after each addition,
as diredted by Macquer. The ftrength and caufticity
of the ammoniac are of moft effential confequence. If,
upon the addition of the firft drop or two of the tinc¬
ture, a denfe opaque coagulated precipitate is formed,
not much unlike that which appears on dropping a fo¬
lution of filver into water (lightly impregnated with
common fait, it is too ftrong, and muft be diluted with
alcohol. A confiderable proportion of the tindlure,
perhaps one to four, ought to be employed to give the
liquor the proper degree of opacity.”
EAVES, in ArchiteBure, the margin or edge of the
roof of a houfe 5 being the lowed tiles, dates, or the
like, that hang over the walls, to throw off water to a
diftance from the wall.
EAVF.s-Droppers, are fuch perfons as (land under the
eaves, or walls, and windows of a houfe, by night or
day, to hearken after news, and carry it to others, and
thereby caufe ftrife and contention in the neighbour¬
hood. They are called evil members of the common*
wealth by the ftat. of Weft. I. c. 33. They may be
punilhed either in the court leet by way of prefentment
and fine, or in the quarter feflions by indidlment and
binding to good behaviour.
EBBING of the Tides. See Tide.
EBDOMARIUS, in ecclefiaftical writers, an offi¬
cer formerly appointed weekly to fuperintend the per¬
formance of divine fervice in cathedrals, and preferibe
the duties of each perfon attending in the choir, as to
reading, finging, praying, &c. To this purpofe the
ebdomary, at the beginning of his wreek, drew up in
form a bill or writing of the refpeftive perfons, and
their feveral offices, called tabula, and the perfons there
entered wrere ftyled intabulati.
EBDOME, Efido/LtYi, in antiquity, a feftival kept on
the feventh of every lunar month, in honour of Apollo,
to whom all feventh days were facred, becaufe one of
them was his birth-day j wdience he was fometimes cal¬
led Ebdomagenes. For the ceremonies of this folemni-
ty fee PotteBs Archccol. Greec. lib. ii. cap. 20.
EBEN US, the ebony tree. See Botany Index.
EBION, the author of the herefy of the Ebionites,
was a difciple of Cerinthus, and his fucceffor. He im¬
proved upon the errors of his mafter, and added to
them new opinions of his own. He began his preach¬
ing in Judea : he taught in Afia, and even at Rome.
His tenets infedted the ifie of Cyprus. St John oppo-
fed both Cerinthus . and Ebion in Afia 3 and it is
thought, that this apoftle wrote his gofpel, in the year
97, particularly againft this herefy.
EBIONITES, ancient heretics, who rofe in the
church in the very firft age thereof, and formed them-
felves into a fedl in the fecond century, denying the
divinity of Jefus Chrift.
3 S Origen
E B I [ 5°6 ] E B O
Ebiomtes. ^ Origen takes them to have been fo called from the
v” Hebrew word ebion, which in that language lignifies
poor i becaufe, fays he, they were poor in fenfe, and
wanted underitanding. Eufebius, with a view to the
lame etymology, is of opinion they wrere thus called, as
having poor thoughts of Jefus Chrift, taking him lor
no more than a mere man.
It is more probable the Jews gave this appellation to
the Chriftians in general out of contempt $ becaufe in
the firll times there were fevc but poor people that em¬
braced the Chriftian religion. This opinion Origen
himielf leems to give into, in his book againll Celfus,
where he fays that they called Ebionites, fuch among
the Jervs as believed that Jefus was truly the expected
Me Hi ah.
It might even be urged, with fome probability, that
the primitive Chriftians aflumed the name themfelves,
in conformity to their profefiion. It is certain, Epi-
phanius obierves, they valued themfelves on being
poor, in imitation of the apoftles. The fame Epipha-
nius, however, is of opinion, that there had been a
man of the name of Ebion, the chief and founder of
the feet of Ebionites, contemporary with the Nazarenes
and Cerinthians. He gives a long and exa£t account
of the origin of the Ebionites, making them to have
rifen after the deftruftion of Jerufalem, when the firll
Chriftians, called Nazarenes, went out of the fame to
live at Pella.
The Ebionites were little elfe than a branch of Na¬
zarenes: only that they altered and corrupted in many
things the purity of the faith held among thofe firit
adherents to Chriftianity. For this reafon Origen di-
ftinguiihes two kinds of Ebionites, in his anfwer to
Celfus •, the one believed that Jefus Chrift wTas bom of
a virgin; and the other, that he w’as bom after the
manner of other men.
The firit were orthodox in every thing, except that
to the Chriftian doftrinc they joined the ceremonies of
the Jew’ith law, with the Jews, Samaritans, and Naza¬
renes ; together w’ith the traditions of the Pharifees.
They differed from the Nazarenes, however, in feveral
things, chiefly as to what regards the authority of the
facred writings; for the Nazarenes received all for
Scripture contained in the Jewilh canon ; whereas the
Ebionites rejefted all the prophets, and held the very
names of David, Solomon, Ifaiah, Jeremiah, and Eze¬
kiel, in abhorrence. They alfo rejefted all St Paul’s
epiftles, whom they treated with the utmoft difrefpeft.
They received nothing of the Old Teftament but
the Pentateuch ) which fhould intimate them to have
defeended rather from the Samaritans than from the
Jews. They agreed with the Nazarenes in uling the
Hebrew gofpel of St Matthew, otherwife called the
Gofpel of the Twelve Apoftles •, but they had corrupt¬
ed their copy in abundance of places •, and particularly,
had left out the genealogy of our Saviour, which was
preferved entire in that of the Nazarenes, and even in
thofe ufed by the Cerinthians.
Some, however, have made this gofpel canonical, and
of greater value than our prefent Greek gofpel of St
Matthew : See NazaRENES. Thefe laft, whofe fen-
timents, as to the birth of our Saviour, were the fame
with thofe of the Ebionites, built their error on this
very genealogy.
Beiides the Hebrew gofptl of St Matthew, the
Ebionites had adopted feveral other books, under the
names of St James, John, and the other apoftles : they
alfo made ufe of the Travels of St Peter, which are
fuppofed to have been written by St Clement •, but had
altered them fo, that there was fcarce any thing of
truth left in them. They even made that faint tell a
number of falfehoods, the better to authorife their owtj,
practices. See St Epiphanius, who is very diftixlive on
the ancient herefy of the Ebionites, Hut. 30. But
his account deferves little credit, as, by his own con-
felTion, he has confounded the other fefts with the
Ebionites, and has charged them with errors to which
the firft adherents of this feft were utter ftrangers.
EBONY of Crete. See Ebemjs, Botany Index.
Ebony Wood is brought from the Indies, exceeding¬
ly hard and heavy, fufceptible of a very fine polilh, and
on that account ufed in mofaic and inlaid works, toys,
&c. There are divers kinds of ebony ; the moil: ufual
among us are black, red, and green, all of them the
produft of the iiland of Madagalcar, where the natives
call them differently hazon mainthi, q. d. black wood.
The ifland of St Maurice, belonging to the Dutch,
likewife lurnilhes part of the ebonies uled in Europe.
Authors and travellers give very different accounts
of the tree that yields the black ebony. By fome of
their deferiptions, it ihould be a fort of palm tree; by
others a cytifus, &c. The moil authentic of them
is that of M. Falcourt, who refided many years in Ma-
dagafear as governor thereof*, he afl'ures us, that it
grows very high and big, its bark being black, and its.
leaves refembling thofe of our myrtle, of a deep duf-
ky green colour.
Tavernier affures us, that the ifknders always take
care to bury their trees, when cut down, to make them
the blacker, and to prevent their fplitting when wrought.
F. Plumier mentions another black ebony tree, difeo-
vered by him at St Domingo, v’hich he calls ffiartium
portulacw foliis aculcatum ebeni materia. Candia alio
l>cars a little fhrub, known to the botanifts under the
name of Ebenvs Cretica, above deferibed.
Pliny and Diofcorides fay the heft ebony comes from
Ethiopia, and the w’orft from India 5 but Theophraftus
prefers that of India. Black ebony is much preferred
to that of other colours. The bell is a jet black, free
of veins and rind, very maffive, aftringent, and of an
acrid pungent tafte. Its rind, infufed in water, is faid
to purge pituita, and cure venereal diiorders 5 w hence
Matthiolus took guaiacum for a fort of ebony. It
yields an agreeable perfume wrhen laid on burning coals :
when green, it readily takes fire from the abundance of
its fat. If rubbed againft a ftone, it becomes brow n.
The Indians make ftatues of their gods, and feeptres
for their princes, of this wood. It was firit brought to
Rome by Pompey, after he fubdned Mithridates. It
is now much lefs ufed among us than anciently, fince
the difeovery of fo many w ays of giving other hard
woods a black colour.
As to the green ebony, befides Madagafcar and St
Maurice, it likewife grows in the Antilles, and efpe-
cially in the iile of Tobago. The tree that yields it is-
very buihyits leaves are imooth, and of a fine green
colour. Beneath its bark is a white blea, about tw*a
inches thick j all beneath which, to the very heart, is
a deep green, approaching towards a black, though
iometimes ftreaked with yellow veins. Its ufe is not
confined
Ebony.
EGA
t 507 J
EGG
JSlnracatn confined to inofaic work : it is likewise good in dyeing,
as yielding a fine green tindture. As to red ebon\,
called alfo grenadiltay we know little of it more than
1 the name.
The cabinet-makers, inlayers, Sec. make pear tree
and other woods pafs for ebony, by giving them the
black colour thereof. This fome do by a few walhes
of a hot decoftion of galls -, and when dry, adding
writing ink thereon, and polilhing it with a Itiff bruih,
and a little hot wax and others heat or bum their
wood black.
EBORACUM, in Ancient Geography, a famous
city of the Brigantes in Britain, the refidence of Sep-
timius Severus and Conftantius Cnlorus, and where
they both died } a Roman colony j and the ilation of
the Legio Sexta Vidtrix. Nowr York. W. Long. 50.
Lat. 54. Caer-froch or Caer-effroc, in Britiih (Cam-
EBRO, anciently Iberus, a large river of Spain,
which, taking its rife in Old Caftile, runs through Bil-
cay and Arragon, paffes by Saragoffa, and, continuing
its courfe through Catalonia, dilcharges itfelf with
great rapidity into the Mediterranean, about 20 miles
below the city of Tortofa.
EBUDdE, or HebudES, in Ancient Geography,
iflands on the weft of Scotland. The ancients dift'er
greatly as to their fituation, number and names , faid
in general to he to the north of Ireland and weft of
Scotland. Now called the Wejiern Ijles, alfo Hebrides;
this laft a modern name, the reafon of which does not
appear, unlefs it be a corruption of Hebudes. By Beda
called Mevanice, an appellation equally obfcure.
EBULLITION, the fame with Boilixg. The
word is alfo ufed in a fynonymous fenfe with Effer¬
vescence.
EBUSUS, in Ancient Geography, the greater of the
two illands called Pityufae, in the Mediterranean, near
the call coaft of Spain, to the fouth-weft of Majorca.
Famous for its paftures for cattle, and for its figs.
Now Ivica, 100 miles in compafs, without any noxious
animals but rabbits, who often deftroy the corn.
ECALESIA, in antiquity, a feftival kept
in honour of Jupiter, fumamed Hecalus, or Hecalejius,
from Hecale, one of the borough towns in Attica.
ECASTOR, in antiquity, an oath wherein Caftor
was invoked. It wras a cuftom for the men never to
fwear by Caftor, nor the women by Pollux.
EC ATE A, in antiquity, ftatues eredted to
the goddefs Hecate, for whom the Athenians had a
great veneration, believing that ihe was the overfeer of
their families, and that (he protected their children.
ECATESIA, E**V<*, in antiquity, an anniverfary
Solemnity, obferved by the Stratonicenfians, in honour
of Hecate. The Athenians like wife had a public en¬
tertainment or fupper every new moon, in honour of
the fame goddefs. The fupper was provided at the
charge of the richer fort y and was no fooner brought
to the accuftomed place but the poor people carried all
off, giving out that Hecate had devoured it. f or the
reft of the ceremonies obferved on this occafion, fee
Jdott. Arch. Greec. lib. ii. cap. 20.
EC AT O M R/EON, Ex-xley^v, in Chronology, the
firft month of the Athenian year. It cenfifted of 30
xlays, and began on the firft new moon after the fum-
mer folftice, and confequently anfwered to the latter EcavefTade
part of our June and beginning of July. The Ere011* Ecc;eflafl;es
ans called it Hippodromus, and the Macedonians Lous. ——J
See Month. The w7ord is a derivative from the Greek
a hecatomb,, becaufe of the great number of
hecatombs facrificed in it.
ECAVESSADE, in the manege, is ufed for 4 jerk
of the caveffon.
ECBATANA, in Ancient Geography, the royal re¬
fidence and the capital of Media, built by Deioces king
of the Medes, according to Herodotus : Pliny fays, by
Seleucus j but that could not be, becaufe it is men¬
tioned by Demofthenes. It was fituated on a gentle
declivity, diftant 12 ftadia from Mount Orontes, and
was in compafs 150 ftadia. Here flood the royal tiea-
fury and tombs. It was an open unwalled town, but
had a very ftrong citadel, encompaffed with leven w alls,
one within and riling above another. I he extent ot
the outmoft wras equal to the whole extent of Athens,
according to Herodotus-, the fituation favouring this
conitrudlion, as being a gentle afcent, and each wall
was of a different colour.— Another Lcbatana of Per-
fia, a town of the Magi (Pliny).—A third of Syria.
ECCENTRICITY. See Excentricity.
ECCHELLENSIS, Abraham, a learned Maro-
nite, whom the prefident Le Jai employed in the edi¬
tion of his Polyglott Bible. G abriel Siorvita, his coun¬
tryman, drew him to Paris, in order to make him his
fellow labourer in publifhing that Bible. They fell out 5
Gabriel complained to the parliament, and cruelly de¬
famed his affociate -, their quarrel made a great nolle.
The congregation de propaganda fide affociated him,
1636, with thole whom they employed in making an
Arabic tranllation of the Scriptures. I hey recalled
him from Paris, and he laboured in that tranflation at
Rome in the year 1652. WLile he was profeffor ol
the Oriental languages at Rome, he was pitched upon
by the great duke Ferdinand II. to tranflate from A—
rabic into Latin the 5th, 6th, and 7th books of Apol¬
lonius’s Conics j in which he was alhfted by John Al-
phonfo Borelli, who added commentaries to them. He
died at Rome in 1644.
ECCHYMOSIS, from to pour out, or from
»|, out of, and juice. It is an eftufion ol hu¬
mours from their refpective velfels, under the integu¬
ments -, or, as Paulus ALgineta fays, “ When the flefli
is bruifed by the violent collilion of any objebl, and its
fmall veins broken, the blood is gradually difcharged
from them.” This blood, when collefted under the
Ikin, is called ecchymtfis, the Ikin in the mean time
remaining entire ", lometimes a tumour is formed by it,
which is foft and livid, and generally without pain. It
the quantity of blood is not confiderable, it is ulually
reforbed; if much, it fuppurates : it rarely happens
that any further inconvenience follows) though, in
cafe of a very bad habit of body, a mortification may
lie the refult, and in fuch cafe regard mull be had
thereto.
ECCLAIRCISSEMENT. See Esclaircisse-
MENT.
ECCLESIASTES, a canonical book of the Old
Teftament, the defign of which is to Ihow the vanity
of all fublunary things.
■It was compofed by Solomon) who enumerates the
^ S 2 feveral
E C C t 508 ] E C C
Ecclefiafti- feveral objects on which men place their happinefs,
, ca^ and then iliows the infufficiency of all worldly enjoy-
/ ^ ments.
The Talmudifls made King Hezekiah to be the
author of it : Grotius afcribes it to Zorobabel, and
others to Ifaiah j but the generality of commentators
believe this book to be the produce of Solomon’s re¬
pentance, after having experienced all the follies and
pleafures of life.
ECCLESIASTICAL, an appellation given to
whatever belongs to the church : thus we fay, ecclefia-
ftical polity, jurifdiclion, hiftory, &c.
Blacljlone't Ecclesiastical Courts. In the time of the Anglo-
Comment. Saxons there' was no fort of diilinftion between the
lay and the ecclefiaftical jurifdiftion : the county court
was as much a fpiritual as a temporal tribunal: the
rights of the church were afcertained and afferted at
the fame time, and by the fame judges, as the rights
of the laity. For this purpofe the bilftop of the dio-
cefe, and the alderman, or in his abfence the Iheriff of
the county, ufed to lit together in the county court,
and had there the cognizance of all caufcs as well ec-
cleliaftical as civil; a fuperior deference being paid to
the bilhop’s opinion in fpiritual matters, and to that
of the lay judges in temporal. This union of power
was very advantageous to them both : the prefence of
the bilhop added weight and reverence to the Iheriff’s
proceedings; and the authority of the Iheriff was equal¬
ly ufeful to the bilhop, by enforcing obedience to his
decrees in fuch refraclory offenders as would other-
wife have defpifed the thunder of mere eccleffaftical
cenfures.
But fo moderate and rational a plan was wholly in-
conliftent with thofe views of ambition that were then
forming by the court of Rome. It foon became an
ellablilhed maxim in the papal fyltem of policy, that
all eccleffaftical perfons, and all ecclefiaftical caufes,
Ihould be folely and entirely fubjeft to eccleffaftical ju-
rifdicHon only : which jurifdiftion was fuppofed to be
lodged in the firft place and immediately in the Pope,
by divine indefeafible right and inveftiture from Chrift
himfelf, and derived from the Pope to all inferior tri¬
bunals. Hence the canon law lays it down as a rule,
that “ facerdotes a regibus honorandi funt, nonjudicandi;
and places an emphatical reliance on a fabulous tale
which it tells of the emperor Conftantine, That when
feme petitions were brought to him, imploring the aid
of his authority againft certain of his biftiops accufed
of oppreflion and injuftice j he caufed, (fays the holy
canon) the petitions to be burnt in their prefence, dif-
mifling them with this valediction : “ 7/e, et inter vos
caufas vejlras difcutite, quia dignum non ejl ut nos judice-
mus Deos.
It was not, however, till after the Norman conqueft,
that this doftrine was received in England j when Wil¬
liam I. (whofe title was warmly efpouled by the mo-
nafteries which he liberally endowed, and by the fo¬
reign clergy whom he brought over in fhoals from
France and Italy, and planted in the belt preferments
of the Englilli church) was at length prevailed upon
to eftablim this fatal encroachment, and feparate the
ecclefiaftical court from the civil : whether actuated by
principles of bigotry, or by thofe of a more refined po¬
licy, in order to difcountenance the laws of King Ed¬
ward abounding with the fpirit of Saxon liberty, is not
altogether certain. But the latter, if not the caufe,Ecc!efiafti-
was undoubtedly the confequence, of this feparation : ca^ Courts*
for the Saxon laws were foon overborne by the Nor- 7 ^
man jufticiaries, when the county court fell into difre-
gard by the bilhop’s withdrawing his prefence, in obe¬
dience to the charter of the conqueror j which prohi¬
bited any fpiritual caufe from being tried in the fecu-
lar courts, and commanded the fuitors to appear before
the bilhop only, whofe decifions were diredfed to con¬
form to the canon law.
King Henry I. at his aceflion, among other refto-
rations of the laws of King Edw'ard the Confeffor, re¬
vived this of the union of the civil and eccleffaftical
courts. Which wTas, according to Sir Edward Coke,
after the great heat of the conqueft was pall, only a
reftitution of the ancient law of England. This how¬
ever was ill relilhed by the Popilh clergy, who, under
the guidance of that arrogant prelate Archbilhop An-
felm, very early difapproved of a meafure that put
them on a level wdth the profane laity, and fubjected
fpiritual men and caufes to the infpeflion of the fecu-
lar magiftrates : and therefore, in their fynod at Weft-
minfter, 3 Hen. I. they ordained, that no bilhop Ihould
attend the difeuflion of temporal caufes j w’hich foon
diffblved this newly effected union. And, when upon
the death of King Henry I. the ufurper Stephen was
brought in and fupported by the clergy, we find one
article of the oath which they impofed upon him was,
that ecclefiaftical perfons and ecclefiaftical caufes Ihould
be fubjeft only to the bilhop’s jurifdiftion. And as it
wras about that time that the conteft and emulation be¬
gan between the lawrs of England and thofe of Rome,
the temporal courts adhering to the former, and the
fpiritual adopting the latter, as their rule of proceed¬
ing ; this widened the breach between them, and made
a coalition afterwards impracticable ; which probably
wTould elfe have been effeCted at the general reforma¬
tion of the church.
Ecclefiaftical courts are various ; as the Archdea¬
con’s, the Consistory, the court of Arches, the
Peculiars, the Prerogative, and the great court
of appeal in all ecclefiaftical caufes, viz. the Court of
Delegates. See thefe articles.
As to the method of proceeding in the fpiritual Blackjlone s
courts, it rouft (in the firft place) be acknowledged to Comment.
their honour, that though they continue to this day to
decide many queftions which are properly of temporal-
cognizance, yet juftice is in general fo ably and im¬
partially adminiftered, in thofe tribunals (efpecially of
the fuperior kind), and the boundaries of their power
are now fo well known and eftabliftred, that no mate¬
rial inconvenience at prefent arifes from this jurifdic-
tion ftill continuing in the ancient channel. And,
ftiould any alteration be attempted, great confulion
wTould probably arife, in overturning long eftablilfied
forms, and new-modelling a courfe of proceedings that
has now7 prevailed for feven centuries.
The effabiilhment of the civil law procefs in all the
ecclefiaftical courts wras indeed a mafterpiece of papal
difeernment, as it made a coalition impracticable be¬
tween them and the national tribunals, without mani-
feft inconvenience and hazard. And tjus confideration
had undoubtedly its weight in cauiing this meafure to
be adopted, though many other caules concurred. In
particular, it may be here remarked, that the PandeCts,
or
E C C
[ 5=>9 1
E C H
Ecciefiafti
cal Court'
- or collections of civil law, being written in the Latin
’ tongue, and referring fo much to the will of the prince
and his delegated officers of juftice, fufficiently recom¬
mended them to the court of Rome,, exclufive of their
intrinfic merit. To keep the laity in the. darkeil ig¬
norance, and to monopolize the little fcience which
then exiiled entirely among the monkilh clergy, were
deep-rooted principles of papal policy. And as tnv,
bifhops of Rome affe£ted in all points to mimic the
imperial grandeur, as the fpiritual prerogatives were
moulded on the pattern of the temporal, fo the canon
law procefs was formed on the model of the civil law ;
the prelates embracing, with the utmoft ardour, a me¬
thod of judicial proceedings, which was carried on. in
a language unknown to the bulk of the people, ■which
banifhed the intervention of a jury (that bulwark of
Gothic liberty), and which placed an arbitrary power
of decilion in the bread of a tingle man.
The proceedings in the ecclefiaftical courts are there¬
fore regulated according to the practice of the civil and
canon laws } or rather to a mixture of both, corrected
and new-modelled by their own particular ufages, and
the interpofition of the courts of common law. For,
if the proceedings in the fpiritual court be ever fo re¬
gularly confonant to the rules of the Roman law, yet
if they be manifeftly repugnant to the fundamental
maxims of the municipal laws, to which, upon prin¬
ciples of found policy, the ecclefiaftical procels ought
in every ftate to conform (as if they require two wit-
ceffes to prove a fact, where one will fuffice at common
law) 5 in fuch cafes, a prohibition will be awarded
againft them. But, under thefe reftridftions, their or¬
dinary courfe of proceeding is, firft, by citation, to
call the party injuring before them. Then by libel (h-
bellus, “ a little book”), or by articles drawn out in a
formal allegation, to fet forth the complainant’s ground
of complaint. To this fucceeds the defendant's anfwer
upon oath j wrhen, if he denies or extenuates the charge,
they proceed to proofs by witneffes examined, and their
depofitions taken down in writing by an officer of the
court. If the defendant has any circumftances to offer
in his defence, he muft alfo propound them in what is
called his defenfive allegation, to which he is entitled in
his turn to the plaintiff^s anfwer upon oath, and may
from thence proceed to proofs as well as his antagonift.
The canonical do&rine of purgation, wffiereby the par¬
ties were obliged to anfwer upon oath to any matter,
however criminal, that might be objected againft
them (though long ago overruled in the court of
chancery, the genius of the Engliffi law having broken
through the bondage impofed on it by its clerical
chancellors, and afferted the doctrines of judicial as wTell
as civil liberty), continued till the middle of the laft
century to be upheld by the fpiritual courts *, when
the legiflature- was obliged to interpofe, to teach them
a leilon of fimilar moderation. By the ftatute of
13 Car. IT. c. T 2. it is enacted, that it lhall not be
lawful for any biihoo, or ecclefiaftical judge, to ten¬
der or adminider to any perfon wffiatfoever, the oath
ufually called the oath ex offcio, or any other oath
whereby he may be compelled to cohfefs, accufe, or
purge himfelf of any criminal matter or thing, whereby
he may be liable to any cenfure or puniihment. When
all the pleadings and proofs are concluded, they are re¬
ferred to the confideration, not of a jury,, but of a fm-ScclefiafW
gle judge •, who takes information by hearing advocates caratiop3
on both fides, and thereupon forms his interlocutory de- j|
crce or definitive fentence, at his own difcretion, from jxhinops.
which there generally lies an appeal, in the feveral ftages — v
mentioned in the articles above referred to •, though, if
the fame be not appealed from him in 15 days, it is fi¬
nal, by the ftatute 25 Henry VIII..c. .19.
But the point in which thefe jurifdictions are the
molt defective, is that of enforcing their fentences when
pronounced for which they have no other procefs
but that of excommunication ; which would be often
defpifed by obftinate or profligate men, did not the
civil law ftep in with its aid. See ExC0MMUNICA~
TION.
Ecclesiastical Corporations, are where the mem¬
bers that compofe them are fpiritual perfons. They
were eredted for the furtherance of religion and per¬
petuating the rights of the church. See Corpora¬
tions.
Ecclesiastical State. See Clergy.
E.CCLESIASTICUS, an apocryphal book, gene¬
rally bound up with the Scriptures } fo called, from its
being read in the church, ecclefia, as a book of piety
and inftruction, but not of infallible authority.
The author of this book was a Jew, called Jefus the
fon of Sirach. The Greeks call it the Wifdom of the
fan of Sirach.
ECCOPROTICS, in Medicine, laxative or.loofen-
ing remedies, which purge gently, by foftening the.
humours and excrements, and fitting them for expul-
fion.—The word is compofed of the Greek particle
and xeTrgo?, excrement.
ECDICI, among the ancients, patrons o*
cities, who defended their rights, and took care of the
public money. T heir office relembled that of the mo¬
dern fyndics.
ECHAPE, in the manege, a horfe begot between
a ftallion and a mare of different breeds and countries.
ECHAPER, in the manege, a gallicifm ufed in the
academies, implying to give a horfe head, or to put on
at full fpeed.
ECHENEIS, the Remora. See Ichthyology
Index.
ECHEVIN, in the French and Dutch polity, a
magiftrate elefted by the inhabitants of a city or town,
to take care of their common concerns, and the de¬
coration and cleanlinefs of the city.
At Paris, there is a prevot and four echevins 5 in
other towns, a mayor and echevins. At Amlterdam,
there are nine echevins j and at Rotterdam, feven.
In France, the echevins take cognizance of rents,
taxes, and the navigation of rivers, &c. In Holland,
they judge of civil and criminal caufes j and if the cri¬
minal confeffes himfelf guilty, they can fee their fen¬
tence executed without appeal.
ECH1NATE, or Echinated, an appellation given
to whatever is prickly, thereby refembling the hedge-
hog.
ECHINITES, in Natural Hifiory, the name by
which authors call the folhl centronia, frequently lOund
in our chalk pits.
ECHINOPHORA. See Botany Index.
ECHINOPS. See Botany Index.
ECHINUS,
ECU Is
Ediinus ECHINUS, a genus of animals belonging to the
£>ho orc*er vermes mollufca. See Helminthology
i 'C ‘ Index.
Echinus, in ArchiteBure^ a member or ornament
near the bottom of the Ionic, Corinthian, and Compo-
flte capitals.
j'XHITES. See Botany Index.
ECEIIUM, viper’s bugloss. See Botany Index.
ECHO, or Eccho, a found refle&ed or reverberat¬
ed, from a folid, concave, body, and fo repeated to the
vT.See AC9u' ear *• The word is formed fronr the Greek #}£«*,
found, which comes from the verb fono.
The ancients being wholly unacquainted with the
true caufe of the echo, aferibed it to feveral caufes fuf-
ficiently whimfical. The poets, who were not the
word of their philofophers, imagined it to be a perfon
of that name metamorphofed, and that die affe&ed to
take up her abode in particular places; for they found
by experience, that Are was not to be met with in all.
(See below, Echo in fabulous hifory.) But the mo¬
derns, who know found to coniift in a certain tremor
or vibration in the fonorous body communicated to the
contiguous air,, and by that means to the ear, give a
more confident account of echo.
For a tremulous body, linking on another folid bo¬
dy, it is evident, may be repelled without deftroying
or diminilhing its tremor 5 and confequently a found
may be redoubled by the relilition of the tremulous
body, or air.
But a Ample refleftion of the fonorous air is not
enough to folve the echo : for then every plain furface
of a folid hard body, as being fit to retieft a voice or
found, would redouble it 5 which we find does not
hold.
To produce an echo, therefore, it fhould feem that
.a kind of concameration or vaulting were necelTary, in
order to colled, and by colleding to heighten and in-
creafe, and afterwards retied, the found \ as we find is
the cafe in refleding the rays of light, where a concave
mirror is required.
In effed, as often as a found llrikes perpendicularly
on a wall, behind which is any thing of a vault or arch,
or even another parallel wall, fo often will it be rever¬
berated in the fame line, or other adjacent ones.
For an echo to be heard, therefore, it is neceflary
the ear be in the line of refledion : for the perfon who
made the found to hear its echo, it is neceflary he be
perpendicular to the place which refleds it: and for a
manifold or tautological echo, it is neceflary there be
a number of walls, and vaults or cavities, either placed
behind or fronting each other.
A Angle arch or concavity, &c. can fcarce ever ftop
and refled all the found j but if there be a convenient
dFpofltion behind it, part of the found propagated thi¬
ther, being colleded and refleded as before, will pre-
fent another echo : or, if there be another concavity,
oppofed at a due diftance to the former, the found re-
fleded from the one upon the other will be tofled back
again by this latter, &c.
Many of the phenomena of echoes are well conAder-
ed by the bilhop of Leighs, &c. who remarks, that any
found, falling either diredly or obliquely on any denfe
body of a fmooth, whether plain or arched, fuperficies,
is refleded, or echoes, more or lefs. The farface, fays
-he, muft be fmooth j otherwife the air, by reverbera-
10 ] E C H
tion, will be put out of its regular motion, and the Echo.
found thereby broken and extinguiftied. He adds, that -v—*
it echoes more or lefs, to Ihow, that when all things
are as before deferibed, there is ftill an echoing, though
it be not always heard, either becaufe the dired found
is too weak to beat quite back again to him that made
it *, or that it does return to him, but fo weak, that it
cannot be difeerned •, or that he Hands in a wrong place
to receive the refleded found, which pafles over his
head, under his feet, or on one Ade of him j and which
therefore may be heard by a man Handing in the place
where the refleded found does come, provided no in-
terpofed body intercepts it, but not by him that firft
made it.
Echoes may be produced with different circum-
Hances. For, 1. A plane obflacle refleds the found
back in its due tone and loudnefs; allowance being
made for the proportionable decreafc of the found, ac¬
cording to its diffance.
2. A convex obflacle refleds the found fomewhat
fmaller and fomewhat quicker, though weaker, than
otherwife it would be.
3. A cowvirw obffacle echoes back the found, bigger,
flower, and alfo inverted 5 but never according to the
order of words.
Nor does it feem poflible to contrive any Angle echo,
that fliall invert the found, and repeat backwards ; be-
caule, in fuch cafe, the word lafl fpoken, that is, which
laff occurs to the obflacle, mult be repelled firfl ; w hich
cannot be. For where in the mean time fliould the
firfl words hang and be concealed ; or howq after fuch
a paufe, be revived, and animated again into motion ?
From the determinate concavity or archednefs of
the refleding bodies, it may happen that feme of them
ftiall only echo back one determinate note, and only
from one place.
4. The echoing body being removed farther off, it
refleds more of the found than when nearer ; which is
the reafon why fome echoes repeat but one fyllable,
fome one wrord, and fome many.
5. Echoing bodies may be fo contrived and placed,
as that refleding the found from one to the other, ei¬
ther diredly and mutually, or obliquely and by fuc-
ceflion, out of one found, a multiple echo or many
echoes fliall arife.
Add, that a multiple echo may be made, by lb
placing the echoing bodies at unequal diflances, that
they may refled all one wray, and not one on the other ;
by which means, a manifold fucceflive found will be
heard j one clap of the hands, like many 5 one ha, like
a laughter ; one Angle word, like many of the fame
tone and accent ; and fo one viol, like many of the
fame kind, imitating each other.
Laftly, Echoing bodies maybe fo ordered, that from
any one found given, they {hall produce many echoes
different both as to tone and intenfion. By which
means a muAcal room may be fo contrived, that not
only one inffrument playing therein fliall feem many
of the fame fort and Aze, but even a concert of differ¬
ent ones, only by placing certain echoing bodies fo,
that any note played fliall be returned by them in
3ds, jths, and 8ths.
Echo, is alfo ufed for the place where the repetition
of the found is produced or heard.
Echoes are diftinguiflied into divers kinds, viz.
1. Single,
E C H [ 5s
1. Single, which return the voice but once. Whereof
feme are tonka/, which only return a voice when mo¬
dulated into fome particular mulical tone : Others,
poliifyl/abical, which return many fyllables, words, and
fentences. Of this laft kind is that fine echo m W ood-
ftock park, which Dr Plot affures us, m the day time,
will return very diilinaiy feventeen fyllables, and m the
night twenty. . „ , .
2. Multiple, or tautologicali which return fyllables
and words the fame oftentimes repeated.
In echoes, the place where the fpeaker Hands is call¬
ed the centrum phonicum, and the object or place that
returns the voice, the centrum phonneampticum.
Ax the fepulchre of Metella, wife of Cralius, was an
echo, which repeated what a man faid five times.
Authors mention a tower at Cyzicus, wdrere the echo
repeated feven times. One of the fineft echoes we read
of is that mentioned by Barthius, in his notes on bta-
tius’s Thehais, lib. vi. 50. which repeated the words
a man uttered 17 times : it was on the banks ot the
Naha, between Coblentz and Bingen. Barthius allures
us, he had proved what he rvrites} and had told 17
repetitions. And whereas, in common echoes, the re-
petition is not heard till fome time after hearing the
word fpoke, or the notes fung; in this, the perfon who
fpeaks or fings is fcarce heard at all •, but the repeti¬
tion molt clearly, and always in furprifing varieties j the
echo feeming lometimes to approach nearer, and lome-
times to be further oft. Sometimes the voice is heaid
very diftinctly, and fometimes icarce at all. One heai s
only one voice, and another feveral; one hears the
echo on the right, and the other on the left, &c. At
Milan in Italy, is an echo which reiterates the report
of a piftol 56 times and if the report is very loud, up¬
wards of 60 reiterations may be counted. 1 he firlt
20 echoes are pretty diftinft 5 but as the noife feems
to fly away, and anfwer at a greater diltance, the re¬
iterations are fo doubled, that they can fcarce be count¬
ed. See an account of a remarkable echo under the
article Paisley.
Echo, in Architecture, a term applied to certain
kinds of vaults and arches, mold commonly of the el¬
liptic and parabolic figures, ufed to redouble founds,
and produce artificial echoes. # ,
Echo, in Poetry, a kind of compofition wherein the
laft words or fyllables of each verfe contain fome
meaning, which, being repeated apart, anlwers to
fome queftion or other matter contained in. the verie ,
as in this beautiful one from Virgil :
Crudelis mater magis, an puer mprobut ille?
Improbus ille puer, crudelis tu quoque mater.
The elegance of an echo confifts in giving a newr fenfe
to the laft words *, which reverberate, as it were, the
motions of the mind, and by that means ailebt it with
furprife and admiration.
Echo, in fabulous hiftory, a daughter of the Air
and Tellus, who chiefly refided in the vicinity of the
Cephifus. She was once one of Juno’s attendants,
and became the confidant of Jupiter’s amours. Her
loquacity, howrever, difpleafed Jupiter, and ihe was de¬
prived of the power of fpeech by Juno, and only per¬
mitted to anfwrer to the queftions which wrere put to
her. Pan had formerly been one of her admirers, but
lie never enjoyed her favours. Echo, after fhe had
t 3 E C H
been punifhed by Juno, fell in love with Narcifiusj but kcTTon-eter
being defpifed by him, pined herfelf to death, having £c!l,[l.t;Cj
nothing but her voice left. ^ —-y——1
ECHOMETER, among muficians, a kind of fcaie
or rule, with feveral lines thereon, ferving to meafure
the duration and length of founds, and to find their .in¬
tervals and ratios.
ECHOUERIES. See under Trichecus.
ECKIUS, John, an eminent and learned divine,-
profeffor in the univerfity of Ingolftadt, memorable
for the oppofition he gave to Luther, Melanclhon,
Caraloftadius, and other leading Proteftants in Ger¬
many. He wrote many polemical tracts; and among
the reft, a Manual of Controverts, printed in 1535,
in which he difeourfes upon moft of the heads contefted
between the Proteftants and Papifts. He was a man
of uncommon learning, parts, and zeal, and died in
I543-
ECLECTICS (ecleBici), a name given to lome an¬
cient philofophers, who, without attaching them,
felves to any particular left, took what they judged^
good and folid from each. Hence their denomina¬
tion ; which, in the original Greek, fignifies, “ that
may be chofen,” or “ that chopfes 5” of the verb
ix-teyu, I choofe.—Laertius notes, that they were alio,
for the fame reafon denominated analogetki; but
that they call themfelves Philalethes, i. e. lovers of
truth.
The chief or founder of the eclectici was one Po-
tamon of Alexandria, who lived under Auguftus and-
Tiberius j and w'ho, weary of doubting of all things
with the Sceptics and Pyrrhonians, formed the eclectic
left ; which Voflius calls the edeclive.
Towards th*e clofe of the fecond century, a fe<ft
arofe in the Chriftian church under the denomination
of EcleBics, or modern Platonics. They profefled to
make truth the only objed of their inquiry, and to
be ready to adopt from all the different fyftems. and
feels fuch tenets as they thought agreeable to it.—
However, they preferred Plato to the other philofo¬
phers, and looked upon his opinions concerning God,
the human foul, and things invifible, as conformable to
the fpirit and genius of the Chriftian doclrine. One of
the principal patrons of this fyftem was Ammonias
Saccas, who at this time laid the foundation of that
fed, afterwards diftinguiftied by the name of the new
Platonics, in the Alexandrian fchool. See AMMONIUS
and Platonists.
Eclectics were alfo a certain fet of phyficians
among the ancients, of whom Aichigenes, under Tra¬
jan, was die chief, who felefted frem the opinions of
all the other fefts that which appeared to them belt
and moft rational j hence they are called ec/eclks, and
their preferiptions medicina ecleCfica.
ECLIPSE, in AJlronomy, the deprivation of the
light of the fun, or of fome heavenly body, by the in-
terpofition of another heavenly body between our fight
and it. See Astronomy Index.
ECLIPTA, in Botany, a genus of the polygamia
fuperflua order, belonging to the fyngenefia clafs of
plants. The receptacle is chaffy ; there is no pappus,.
and the corollulae of the dilk quadrifid.
ECLIPTIC, in AJlronomy, a great circle of the
fphere, fuppofed to be drawn through the middle of the
zodiac, making an angle with the equinoctial of about
E C T [ 5
Ecliptic
if.
Ectylotic.
230 30,> which is the fun’s great eft declination j or,
more ftridlly fpeaking, it is that path or way among the
fixed ftars, that the earth appears to defcribe to an eye
placed in the fun. See Astronomy Index.
Some call it via Solis, “the way of the fun}” becaufe
the fun in his apparent annual motion never deviates
from it, as all the other planets do more or lefs.
Ecliptic, in Geography, a great circle on the ter-
■re(trial globe, not only anfwering to, but falling within,
the plane of the celeftial ecliptic. See Geography.
ECLOGUE, in Poetry, a kind of paftoral com-
pofition, wherein (hepherds are introduced converfing
together. The word is formed from the Greek ix.'Koy*
■choice; fo that, according to the etymology, eclogue
ihould be no more than a fele£t or choice piece} but
cuftom has determined it to a farther fignification, viz.
a little elegant compofition in a fimple natural ftyle and
manner.
Idyllion and eclogue, in their primary intention, are
the fame thing : thus, the idyllia, of Theocri¬
tus, are pieces wrote perfectly in the fame vein with the
eclogce of Virgil. But cuftom has made a difference be¬
tween them, and appropriated the name eclogue to pieces
wherein (hepherds are introduced fpeaking : idyllion, to
thofe wrote like the eclogue, in a fimple natural ftyle,
but without any (hepherds in them.
ECLUSE, a fmall but ftrong town of the Dutch
Low Countries, in the county of Flanders, with a good
harbour and (luices. The Englifh befieged it in vain in
1405, and the people of Bruges in 1436. But the
Dutch, commanded by Count Maurice of Naffau, took
it in 1644. It is defended by feveral forts, and (lands
near the fea. E. Long. 3. 10. N. Lat. 50. 25.
ECONOMY, Political. See Political Eco-
I
nomy.
ECPHRACTICS, in Medicine, remedies which at¬
tenuate and remove obftrudlions. See Attenuants,
and Deobstruents, Materia Medic a Index.
ECSTASY. See Extasy.
ECSTATICI, ’Eutxthcoi, from 1 am entran¬
ced, in antiquity, a kind of diviners who were caft into
trances or ecftafies, in which they lay like dead men,
or afleep, deprived of all fenfe and motion } but, after
fome time, returning to themfelves, gave ftrange rela¬
tions of what they had feen or heard.
ECTHESIS, in church hiftory, a confefiion of
faith, in the form of anedicl, publiihed in the year 639,
by the emperor Heraclius, with a view to pacify the
troubles occafioned by the Eutychian herefy in the
eaftern church. However, the fame prince revoked it,
on being informed that Pope Severinus had condemned
it, as favouring the Monothelites} declaring at the fame
-time, that Sergius, patriarch of Conftantinople, was
the author of it.
ECTHLIPSIS, among Latin grammarians, a fi¬
gure of profody, whereby the m at the end of a word,
-when the following word begins with a vowel, is elided,
or cut off, together with the vowTel preceding it, for the
fake of the meafure of the verfe : - thus they read mulp
ille, for multum ille.
ECTROPIUM, in Surgery, is when the eyelids are
inverted, or retraced, fo that they (how their internal
■or red furface, and cannot fufficiently cover the eye.
ECTYLOTICS, in Pharmacy, remedies proper for
^onfuroing callofities.
I
2 ] E D D
ECU, or Escu, a French crown j for the value of Ecu
which, fee Money. I!
ED AY, one of the Orkney ifles, is about five miles
and a half long, and about a mile and a half broad.
It has feveral good harbours, and contains about 600
inhabitants.
EDDA, in antiquities, is a fyftem of the ancient
Icelandic or Runic mythology, containing many cu¬
rious particulars of the theology, philofophy, and
manners, of the northern nations of Europe 5 or of
the Scandinavians, who had migrated from Alia, and
from whom our Saxon anceftors wTere defcended. Mr
Mallet apprehends that it was originally compiled,
foon after the Pagan religion was abolifhed, as a courfe
of poetical ledlures, for the ufe of fuch young Ice¬
landers as devoted themfelves to the profeflion of a
fcald or poet. It confifts of twro principal parts } the
JirJl containing a brief fyftem of mythology, properly
called the Edda; and the fecond being a kind of art of
poetry, and called fcalda or poe'tics. The mod ancient
Edda was compiled by Soemund Sigfuffon, furnam-
ed the Learned, who was born in Iceland about the
year 1057. This wras abridged, and rendered more
eafy and intelligible about 120 years afterwards, by
Snorro Sturlefon, who wras fupreme judge of Iceland
in the years 1215 and 1 222 } and it was publifhed in
the form of a dialogue. He added alfo the fecond
part in the form of a dialogue, being a detail of dif¬
ferent events tranfadled among the divinities. The
only three pieces that are knowm to remain of the more
ancient Edda of Soemund, are the Volufpa, the Hava-
maal, and the Runic chapter. The Volufpa, or pro¬
phecy of Vola or Fola, appears to be the text, on
which the Edda is the comment. It contains, in twn>
or three hundred lines, the whole fyftem of mythology
difclofed in the Edda, and may be compared to the
Sibylline verfes, on account of its laconic yet bold ftyle,
and its imagery and obfcurity. It is profeffedly a re¬
velation of the decrees of the Father of nature, and
the actions and operations of the gods. It defcribes
the chaos, the formation of the world, with its various
inhabitants, the function of the gods, their mod fignal
adventures/ their quarrels wnth Loke their great ad-
verfary, and the vengeance that enfued} and con¬
cludes with a long defcription of the final (late of the
univerfe, its diffolution and conflagration, the battle of
the inferior deities and the evil beings, the renova¬
tion of the world, the happy lot of the good, and the
puniftiment of the wacked. The Havamaal, or Sub¬
lime Difcourfe, is attributed to the god Odin, wrho is
fuppofed to have given thefe precepts of wifdom to
mankind} it is comprifed in about 120 ftanzas, and re-
fembles the book of Proverbs. Mr Mallet has given fe¬
veral extrafts of this treatife on the Scandinavian ethics.
The Runic chapter contains a (hort fyftem of ancient
magic, and efpecially of the enchantments wrought by
the operation of Runic charatters, of which Mr. Mal¬
let has alfo given a fpecimen. A manufcript copy of
the Edda of Snorro is preferved in the library of the
univerfity of Upfal} the firll part of which hath been
publifhed with a Swedifh and Latin verfion by M.
Goranfon. The Latin verfion is printed as a fupple-
ment to M. Mallet’s Northern Antiquities. The firft
edition of the Edda was publilhed by Refenius, pro-
feffor at Copenhagen, in a large quarto volume, in the
year
E D E [ 51
year t66c *, containing the text of the Edda, a I.atin
tranflation by an Icelandic prieft, a Danifh veifion,
and various readings from different MSS. M. Mallet
has alfo given an Englilh tranflation of the firft part,
accompanied with remarks •, from which we learn, that
the Edda teaches the doftrine of the Supreme, called
the Univerfal Father, and Odin, who lives for ever, go¬
verns all his kingdom, and dire&s the great things as
well as the fmall; who formed the heaven, earth, and
air ; made man, and gave him a fpirit or foul, which
fhall live after the body fhall have mouldered away 5
and then all the juft fhall dwell with him in a place Gimle
or Vingolf, the palace of friendlhip •, but wicked men
{hall go to Hela, or death, and from thence to Niflheim,
or the abode of the wicked, which is below in the ninth
World. It inculcates alfo the belief of feveral inferior
gods and goddefles, the chief of whom is Irigga or
Frea, i. e. lady, meaning hereby the earth, who was
the fpoufe of Odin or the Supreme God j whence
we may infer that, according to the opinion of theie
ancient philofophers, this Odin was the adive prin¬
ciple or foul of the world, which uniting itfelf with
matter, had thereby put it into a condition to pro¬
duce the intelligences or inferior gods,, and men and
all other creatures. The Edda likewife teaches the
exiftence of an evil being called Lohe, the calumnia¬
tor of the gods, the artificer of fraud, who furpaffes-
all other beings in cunning and perfidy. It teaches
the creation of all things out of an abyfs or chaos j
tlie final deftrudion of the world by fire *, the ablorp-
tion of the inferior divinities, both good and bad, into
the bofom of the grand divinity, from whom all things
proceeded, as emanations of his eflence, and ■nho will
furvive all things •, and the renovation of the earth in
an improved ftate.
EDDISH, or Eadish, the latter pafture or grafs
that comes after mowing or reaping > otherwife called
eagrafe or earjh, and etch,
EDDOES, or Edders, in Botany, the American
name of the Arum efculentum,
EDDY (Saxon), of ed “ backward,” and ea
“ water,” among feamen, is where the water runs
back contrary to the tide 5 or that which hinders the
free paflage of the rtream, and fo caufes it to return
again. That eddy water which falls back, as it were,
on the rudder of a fhip under fail, the feamen.call the
dead water.
Eddy Wind is that which returns or is beat back
from a fail, mountain, or any thing that may hinder
its paffage.
EDELINCK, Gerard, a famous engraver, born
at Antwerp, where he was -inftruded in drawing and
engraving. He fettled at Paris, in the reign of
Louis XIV. who made him his engraver in ordinary.
Edelinck was alfo counfellor in the Royal Academy
of Painting. His works are particularly efteemed for
the neatnefs of the engraving, their brilliant caft, and
the prodigious eafe apparent in the execution} and
to this facility is owing the great number of plates
we have of his •, among which are excellent portraits
of a great number of illuftrious men of his time.
Among the moft admired of his prints, the fol¬
lowing may be fpecified as ‘holding the chief place.
I. A battle between four horfemen, with three figures
lying flain upon the ground, from Leonardo da Vinci.
■Vox.. VII. Part II.
Eden
3 1 . . E D H
2. A holy family, with Elizabeth, St John, and two
angels, from the famous picture of Raphael in the king Edhiling<
of France’s collection. The firft impreffipns are before ,  —-
the arms of M. Colbert were added at the bottom 01
the plate 5 the fecond are with the arms > and in the
third the arms are taken out, but the place where they
had been inferted is very perceptible. 3. Mary Mag¬
dalen bewailing her fins, and trampling upon the riches
of the world, from Le Brun. The firft impreffions are
without the narrow border which furrounds the print.
4. Alexander entering into the tent of Darius, a large
print on two plates, from Le Brun.. T his dngraving
belongs to the three battles, and triumphal entry ot
Alexander into Babylon, by Girard Audran, and
completes the fet. The firft impreflions have the
name of Goyton the printer at the bottom. 5. Alex¬
ander entering into the tent of Darius (finifhed b\
P. Drevet), from Peter Mignard. Edelinck died in
1707, in an advanced age, at the Hotel Royal at the
Gobelins, wdiere he had an apartment. He had a
brother named John, who was a {kilful engraver, but
died young.
EDEN, (Mofes) the name of a country, with a
garden, in which the progenitors of mankind were
fettled by God himfelf: The term denotes pleafure
or delight. It would be endlefs to recount the le-
veral opinions concerning its fituation, fome of them
very wild and extravagant. Mofes fays, that “ a ri¬
ver went out of Eden to water the garden, and from
thence it was parted and became into four heads.”
This river is fuppofed to be the common channel of
the Euphrates and Tigris, after their, confluence ;
which parted again, below the garden, into two dif¬
ferent channels j fo that the two channels before, and
the other two after their confluence, conftitute the
heads mentioned by Mofes. Which will determine
the fituation of the garden to have been in the fouth
of Mefopotamia, or in Babylonia. The garden was
alfo called Paradife ; a term of Perfic original, denot¬
ing a garden. See Paradise.
EDGINGS, in Gardening, the feries of fmall but
durable plants fet round the edges or borders of flower
beds, &c. ' The belt and moft durable of all plants for
this ufe is box j which, if well planted and rightly ma¬
naged, will continue in ftrength and beauty for many
years. The feafons for planting this are the autumn,
and very early in the fpring : and the beft fpecies for
this purpofe is the dwarf Dutch box.
Formerly, it was alfo a very common practice to
plant borders, or edgings, of aromatic herbs j as thyme,
favory, hyffop, lavender, and the like : but thefe are
all apt to grow woody, and to be in part, or wholly,
deftroyed in hard winters. Daifies, thrift, or fea july-
flower, and chamomile, are alfo ufed by fome for this
purpofe : but they require yearly tranfplanting, and a
great deal of trouble, elfe they grow out of form \ and
they are alfo fubjedt to perifti in very hard feafons.
EDHILING, Edhilingus, an ancient appellation
of the nobility among the Anglo-Saxons.
The Saxon nation, fays Nithard (Hill. lib. iv.) is
divided into three orders or claffes of people j the edhi-
lingi, the frihngi, and the /axon; which fignify the no¬
bility, the freemen, and the vaflals or {laves.
Inftead of edhiling, we fometimes meet with athehng,
or cvthelinr *, which appellation was likewife given to
3T the
Origin of
the name.
EDI [5
E4',ft the king’s fon^ and the prefumptive heir of the crown.
n , See Atheling.
Edinburgh. xr ta t r
,v——y—«—> -M.iJiL'l, m matters of polity, an order or inftru-
xnent, figned and lealed by a princej to ferve as a law
to his fubjefls. We find frequent mention of the edifts
of the praetor, the ordinances of that officer in the
Roman law. In the French law, the edidls are of fe-
t erai kinds : fome importing a new law or regulation j
others, the erection of new offices; eftabliffiments of
1.uties, rents, &c. j and lometimes articles of pacifica¬
tion. In France, edicts are much the fame as a pro¬
clamation is with us : but with this difference, that the
former have the authority of a law in themlelves, from
the power which iffues them forth ; whereas the latter
are only declarations of a law, to which they refer, and
have no power in themfelves.
EDILE, or ALdile. See A5dile.
EDINBURGH, a city of Mid-Lothian in Scot-
, land, fituated in W. Long. 30, and N. Lat. 56°, near
the fouthem bank of the river Forth.—The origin of the
name, like that of moft other cities, is very uncertain.
Some imagine it to be derived from Eth, a fuppofed
king of the Pifts 5 others from Edwin, a Saxon prince
of Northumberland, who overran the whole or greateft
part of the territories of the Picffs about the year 6175
while others choofe to derive it from twro Gaelic
words Dun Edin, fignifying the face of a hill. The
name Edinburgh itfelf, however, feems to have been
unknown in the time of the Romans. The moft an¬
cient title by which we find this city diftinguiffied is
that of Cajlelh Mijnyd Agncd; which, in the Britiffi lan¬
guage, fignifies “ tlie fortrefs of the hill of St Agnes.”
Afterwards it was named Cajirum Puellaruin, becaufe
the Pi&ilh princeffes were educated in the caftle (a ne-
ceffary proteftion in thofe barbarous ages) till they
were married.—The ages in which thefe names were
its founda- given cannot indeed now be exactly afcertained : but
*aiii UnCer‘ the tmvn certainly cannot boaft of very great antiquity;
fince, as Mr Whittaker informs us, the celebrated King
Arthur fought a battle on the fpot where it is fituated
towards the end of the fifth century.
The Romans, during the time they held the domi¬
nion of part of this ifland, divided their poffeffions into
fix provinces. The moft northerly of thefe was called
Valentin, which comprehended all the fpace between
the walls of Adrian and Severus. Thus, Edinburgh,
lying on the very outfkirts of that province ■which was
molt expofed to the ravages of the barbarians, became
perpetually fubjeft to wars and devaftations; by means
of which, the time of its firft foundation cannot now be
gueffed at..
The caftle is certainly very ancient. It continued
in the hands of the Saxons or Englifh from the inva-
fion of 0<fta and Ebufa in the year 45 2 till the defeat
of Egfrid king of Northumberland in 685 by the Pitf s,.
who then repoffeffed themfelves of it. The Saxon
kings of Northumberland reconquered it in the ninth
century} and it was retained by their fucceffors till
the year 956, when it was given up to Indulphus
king of Scotland. In 1093 it was unfuccefsfully be-
fieged by the ufurper Donald Bane. Whether the city
was at that time founded or not is uncertain. Moft
probably it was: for as prote&ion from violence was
aeceffary in thofe barbarous ages, the caftle of Edin¬
burgh could not fail of being an inducement to many
Time of
14 ] EDI
people to fettle in its neighbourhood-, and thus the Edinburgh.
city wrculd gradually be founded and increafe. In v——-v—
1128, King David I. founded the abbey of Holy-
roodhoufe, for certain canons regular: and granted
them a charter, in which he ftyled the town Burgo meo
de Edwinejburgh, “ my borough of Edinburgh.” By
the fame charter he granted thefe canons 40 fhillings
yearly out of the town revenues ; and likewdfe 48 ffiil-
hngs more, from the fame, in cafe of the failure of cer¬
tain duties payable from the king’s revenue ; and like-
wife one half of the tallow, lard, and hides, of all the
hearts killed in Edinburgh.
In 1174, the cable of Edinburgh was furrendered toCaftie fur-
Henry II. of England, in order to purchafe the liberty rendered to
of King William I. who had been defeated and takenthe EngIifll*
prifoner by the Engliffi. But when William recovered
his liberty, he. entered into an alliance with Henry,
and married his coufin Ermengarde ; upon which the
caftle was reftored as part of the queen’s dow-er.
In 1 215, this city was firft diftinguilhed by having a
parliament and provincial fynod held in it. In I 296,
the caftle was befieged and taken by Edward I. of
England j but was recovered in 1313 by Randolph earl
of Moray, who was afterwards regent of Scotland dv.
ring the minority of King David II. At laft King
Robert deftroyed this fortrefs, as well as all others in
Scotland, left they ffiould afford Ihelter to the Englifh
in any of their after incurfions into Scotland.—It lay
in ruins for a confiderable number of years ; but was
afterwards rebuilt by Edward III. of England, who
placed a ftrong garrifon in it.
In 1341 it was reduced by the following ftratagem.
A man pretending to be an Englilh merchant, came
to the governor, and told him that he had on board his
ftiip in the Forth fome wine, beer, bifeuits, &c. which
he would fell him on very reafonable terms. A bargain
being made, he promifed to deliver the goods next
morning at a very reafonable rate : but at the time ap¬
pointed, twelve men, difguifed in the habit of failors,
entered the caftle with the goods and fuppofed mer¬
chant : and having inftantly killed the porter and cen-
tinels, Sir William Douglas, on a preconcerted fignal,
ruffied in with a band of armed men, and quickly made
himfelf mafter of the place, after having cut moft of the
garrifon in pieces. ^
The year 143 7 is remarkable for the execution of Cruel exe-
the earl of Athol and his accomplices, who had a con- cutl°n of
cern in the murder of James I. The crime, it muft^e“uJf
be owned, was execrable j but the punilhment was al-jame5 l
together fhocking to humanity. For three days fuc-
ceffively the affaffins were tortured by putting on their
heads iron crowns heated red hot, diflocating their
joints, pinching their fleffi with red hot pinchers, and
carrying them in that dreadful fituation through the
ftreets upon hurdles. At laft an end was put to their
fufferings, by cutting them up alive, and fending the
parts of their mangled bodies to the principal towns of
the kingdom. 5
About the end of the 14th century it was cuftom-Edinburgh
ary to confider Edinburgh as the capital of the king-kec?mes^1®
dom. The town of Leith, with its harbour and mills, ^otlaluL
had been beftowed upon it by Robert I. in 1329} and
his grandfon John earl of Garrick, who afterwards
afeended the throne by the name of Robert III. con¬
ferred upon all the burgeffes the fingular privilege of
building
Edinburgh
Venereal
difeafe im
ported.
. 7 c
Origin of
the town
guard.
EDI [ S'
building boufes in tbe caftle, upon the foie condition
that they fhould be perfons of good fame j which we
muft undoubtedly conlider as a proof that the number
of thefe burgeffes was at that time very Imall. ^ In
1461, a very conliderable privilege was conferred on
the city by Henry VI. of England when in a ftate of
exile • viz. that its inhabitants Ihould have liberty to
trade’to all the Englilh ports on the fame terms with
the city of London. This extraordinary privilege was
bellowed in confequence of the kindnefs with which
that king was treated in a vifit to the Scottifh
monarch at Edinburgh 5 but as Henry was never re-
ftored, his gratitude was not attended with any bene¬
fit to this city. From this time, however, its privi¬
leges continued to be increafed from various caufes.
In 1482 the citizens had an opportunity of libe¬
rating King James from the oppreflion of his nobles,
by whom he had been imprifoned in the caftle. On
this account the provoft was by that monarch made
hereditary high ftieriff within the city, an office which
he continues ftill to enjoy. ihe council at the
fame time were invefted with the power of. making
law? and ftatutes for the government of the city; and
the trades, as a teftimony of the royal gratitude for
their loyalty, received the banner known by the name
of the Blue Blanket; an enfign formerly capable of
producing great commotions, but which has not now
been difplayed for many years paft. However, it ftill
exifts j and the convener of the trades has the charge
of keeping it.
It was not long after the difeovery of America that
the venereal difeafe, imported from that country, made
its way to Edinburgh. As early as 1497* hve
years after the voyage of Columbus we find it looked
upon as a moft dreadful plague} and the unhappy per¬
fons affected with it were feparated as effeftually as pof-
fible from fociety. The place of their exile was Inch-
keith, a fmall ifland, near the middle of the forth}
which, fmall as it is, has a fpring of freffi water, and
now affords pafture to fome fheep.
By the overthrow of James IV. at the battle of
Flowden, the city of Edinburgh was overwhelmed
with grief and confufion, that monarch having been
attended in his unfortunate expedition by the earl of
Angus, then provoft, with the reft of the magiftrates,
and a number of the principal inhabitants, moft of
whom periffied in the battle. After this difafter, the
inhabitants being alarmed for the fafety of their city,
it was enacted that every fourth man ffiould keep
watch at night} the fortifications of the town were
renewed, the wall being alfo extended in luch a man¬
ner as to enclole the Grafsmarket, and the field on
which Heriot’s Uofpital, the Grey Friars Church, and
Charity Workhoufe, ftand. On the eaft fide it was
made to enclofe the College, Infirmary, .and High
School} after which, turning to the north, it met the
old wall at the Netherbow port. After this alarm was
over, the inhabitants were gradually relieved from the
trouble of watching at night, and a certain number of
militia appointed to prevent difturbances} who con¬
tinue to this day, and are known by the name ot
the Town Guard. Before thefe new enclofures, moft of
the principal people lived in the Cowgate without the
wall } and the burying place was fituated where the
5 ] EDI
Parliament Clofe now is. In our days of peace, when EdmburgV
no alarm of an enemy is at all probable, great part ot
the walls, with all the gates, have been taken down,
and the city laid quite open, in order to aliorU more
ready paffage to the great concourfe of people with
whom the ftreet is daily filled. But at the period
we fpeak of, not only were the inhabitants much leis
numerous by reafon of the fmall extent of the city,
but it was depopulated by a dreadful plague } io that,
to flop if poffible the progrefs of the mfedhon, all
houfes and (hops were ftiut up for 14 days, and lome
where infeaed perfons had died were pulled down al-
^In 1504, the traa of ground called the Burrougn Ereft.on of
Muir was totally overgrown with wood, though now wooden
it affords not the fmalleft veftige of having been m1
fuch a ftate. So great was the quantity at that time,
however, that it was enaded by the town .council, that
whoever inclined to purchafe as much wood as was
fufficient to make a new front for their houfe, migin
extend it feven feet into the ftreet. I hus the city
was in a Ihort time filled with houfes of wrood inftead
of ftone } by which, befides the inconvenience oi hav¬
ing the ftreet narrowed 14 feet, and the beaut> c.
the wffiole entirely marred, it became much more lia¬
ble to accidents by fire : but almoft all thefe are. now
pulled down } anil in doing this a Angular tafte in the
mafonry which lupported them is faid to have been d. -
covered. _ 1 9
In icq l, a war with England having commenced Edinburgh
through the treachery of Cardinal Beaton, an Engliffi deflaxyed
fleet of 200 fail entered the F orth ■, and having landed ^7,^
their forces, quickly made themfelves matters of the
towns of Leith and Edinburgh. They next attacked
the caftle, but were repulfed from it with lofs } and by
this they wrere fo enraged, that they not only deftroyed
the towns of Edinburgh and Leith, but laid wTafte the
country for a great way round.—Thefe towns, how¬
ever, fpeedily recovered from their ruinous ftate } and,
in 1547, Leith was again burned by the Englffh after
the battle of Pinkey, but Edinburgh was fpared.
Several difturbances happened in this capital, at . the
time of the Reformation, of which an account is given
under the article Scotland } out none of theie greatly
affeaed the city till the year 1570, at which time
there was a civil wrar on account of Mary’s forced re-
lignation. 1 he regent, who was one of the contending
parties, bought the caftle from the perfidious governor
(Balfour) for 50Q0I. and the priory of Pittenweem.
He did not, however, long enjoy the fruits of this in¬
famous bargain. Sir William Kirkaldy, the newr go¬
vernor, a man of great integrity and bravery, declared
for the queen. The city in the mean time was feme-
times in the hands of one party and fom.etime.s of ano¬
ther } during which contentions, the inhabitants, as IO
may eafily be imagined, fuffered extremely. In the Siege of the
year 1570 above mentioned, Queen Elizabeth fent a Qu^en Eli
body of xooo foot and 30O horle, under the cornman^ 1
of Sir William Drury, to affift the king’s party. fhe t;me-
caftle wyas fummoned to furrender} and feveral Ikir-
miffies happened during the fpace of two years, in
which a kind of predatory war wras carried on. At
laft a truce was agreed on till the month of Januaiy
1 C75 } and this opportunity the earl of Morton, now
3 T 2. regent,
EDI [ 5
Edinlmrgli regent, made ufe o£ to build two bulwarks acrofs the
v high llreet, nearly oppofite to the tolbooth, to defend
the city from the fire of the caftle.
On the firit of January, early in the morning, the
governor began to cannonade the city. Some of the
cannon were pointed againlt the fifh-market, then
held on the high ftreet } and the bullets falling among
the fillies, icattered them about in a furprifing manner,
and even drove them up fo high in the air, that they
fell down upon the tops of the houfes. This unufual
fpeftacle having brought a number of people out of
their houfes, fome of them were killed and others
dangeroufly wounded. Some little time afterwards,
feveral houfes were fet on fire by Ihot from the caftle,
and burned to the ground ^ which greatly enraged the
people againft the governor. A treaty was at laft con¬
cluded between the leaders of the oppofite fadions j
but Kirkaldy refufed to be comprehended in it. The
regent therefore folicited the affiftance of Queen Eli¬
zabeth, and Sir William Drury was again lent into
Scotland with i500ifoot and a train of artillery. The
caftle was now befieged in form, and batteries raifed
againft it in different places. The governor defended
himfelf with great bravery for 33 days j but finding
moft. of the fortifications demolilhed, the well choked
up with . rubbilh, and all fupplies of water cut off, he
was obliged to furrender. I he Englilh general, in
the name of his miftrefs, promifed him honourable
treatment^ but the queen of England lhamefully gav&
him up to the regent, by whom he was hanged.
Soon after this, the fpirit of fanaticifm, which fuc-
ceeded the Reformation, produced violent commotions,
not only in Edinburgh, but through the whole king¬
dom. The foundation of thefe dirturbances, and in¬
deed of moft others which have ever happened in Chri-
ftendom on account of religion, was that pernicious
maxim of Popery, that the church is independent of
the ft ate. It is not to be fuppofed that this maxim
was at all agreeable to the fovereign ; but fuch w^as
the attachment of the people to the do£!rines of the
clergy, that King James found himfelf obliged to com¬
pound matters with them. This, howrever, anfwered the
t i purpofe but very indifferently } and at laft a violent up-
Fhe city roar was excited. The king was then fitting in the
dlfpleafure C°Urt °f wllich was held .in the tolbooth,
of James w^en a petition was prefented to him by fix perfons,
VI. lamenting the dangers which threatened religion y and
being treated with very little refpecf by one Bruce a
minilter, his majefty alked who they wrere that dared
to convene againft his proclamation ? He was anfwer¬
ed by Lord Lindfay, that they dared to do more, and
would not fuffer religion to be overthrown. On this
the king perceiving a number of people crowding in¬
to the room, withdrew into another without making
any reply, ordering the door to be fhut. By this the
petitioners were fo much enraged, that on their return
to the church the moft: furious refolutions wrere taken y
and had it not been for the aclivity of Sir Alexander
Home the provoft, and Mr Watt the deacon convener
who affembled the crafts in his majerty’s behalf, it is
more than probable that the door would have been
forced, and an end put to his life. This affront was
fo much refented by the king, that he thought proper
to declare Edinburgh an unfit place of refidence for the
court or the adminiffration of juftice. In confequence
16 ] EDI
of Ihis declaration, he commanded the college of juftice, Edinburgh.
the inferior judges, and the nobility and barons, to ' v—
retire from Edinburgh, and not to return without ex-
prefs licenfe.. This unexpected declaration threw the
whole town into confternation, and brought back the
magiftrates and principal inhabitants to a fenfe of their
duty. With the clergy it was far otherwife. They
railed againft: the king in the moft furious manner ;
and endeavouring to perfuade the people to take
up arms, the magiftrates ivere ordered to imprifon
them .• but they eicaped by a timely ftight. A de¬
putation of the moft refpectable burgeffes was then
ent to the king at Linlithgow, with a view to miti¬
gate his refentment. But he refufed to be pacified ;
and on the laft day of December I596 entered the
town between two rows of his foldiers who lined the
ftreets, while the citizens were commanded to keep
within their houfes. A convention of the eftates was
held in the tolbooth, before whom the magiftrates
made the moft abject fubmiftions, but in vain. The
convention declared one of the late tumults, in which
an attack had been made upon the king’s perfon, to
e high trealon y and ordained, that if the magiftrates
did not find out the authors, the city itfelf ftiould be
fubjeCted to all the penalties due to that crime. It was
even propofed to raze the town to the foundation, and
erect a pillar on the fpot where it had ftood, as a mo¬
nument of its crimes. The inhabitants were now re¬
duced to the utmoft defpair j but Queen Elizabeth in*
terpofing in behalf of the city, the king thought pro*
per to abate fomewhat of his rigour. A criminal
profecution, however, was commenced, and the town
council were commanded to appear at Perth by the firft
of February. On their petition, the time for their ap¬
pearance was prolonged to the firft: of March y and the
attendance of 13 of the common council was declared
fufficient, provided they had a proper commiftion from
the reft. The trial commenced on the 5th day of
the month y and one of the number having failed in his
attendance, the caufe was immediately decided againft
the council; they were declared rebels, and their reve¬
nues forfeited. I2
For 15 days the city continued inf the utmoft confu-P again re-
fion ; but, at laft, on their earneft fupplication, and offceived into
fering tofubmit entirely to the king’s mercy, the com-tavour’
munity were reftored on the following conditions, which
they had formerly proffered : That they Ihould conti¬
nue to make a moft diligent fearch for the authors of
the tumult in order to bring them to condign punilh-
ment y that none of the feditious minifters Ihould be
allowed to return to their charges, and no others ad¬
mitted without his majefty’s confent y and that in the
election of their magiftrates they Ihould prefent a lift
of the candidates to the king and his lords of council
and feflion, whom his majefty and their lordftiips might
approve or rejedl at pleafure. To thefe conditions the
king now added fome others y viz. that the houfes
which had been poffeffed by the minifters Ihould be de¬
livered up to the king y and that the clergymen ihould
afterwards live difperfed through the town, every one
in his own parilh : That the town council houfe fhould
be appointed for accommodating the court of exche¬
quer : and that the .town fhould become bound for the
fafety of the lords of fefiion from any attempts of the
burgeffes, under a penalty of 40*000 merksj and, laftly,
that
EDI [S’
Edinburgh, that the town (liould immediately pay 20,000 merks to
his maiefty. . , , , . ,
Upon thefe terms a reconciliation took place j which
appears to have been very complete, as the king not
only allowed the degraded minifters to be replaced, but
in 1610 conferred "a mark of his favour on the town
by allowing the provoft to have a fword of itate carried
before him, and the magiilrates to wear gowns on pub¬
lic occafions. In 1618 he paid his laft vifitto this city,
when he was received with the moft extravagant pomp
and magnificence. See Scotland.
Proceed- The events which, during this period, regard the
ings of the internal police of the city, were principally the iollow-
magiftrates, jng- After the unfortunate battle at Pinkey, the ma-
&'c' giftrates, probably apprehending that now their power
was enlarged by reafon of the prefent calamity, pro¬
ceeded in fome refpe&s in a very arbitrary manner j
forcing the inhabitants to furnith materials for the pub¬
lic works ; enjoining merchants to bring home filver to
be coined at the mint j and ordering lanterns to be
hung out at proper places to bum till nine at nlght»
See. Another invafion from England beingapprehende
in i c 58, the city raifed 1450 men for its defence, among
whom there are faid to have been . 200 tailors, fo
their profeflion feems to have been in a very nounihing
ftate at that time. During the dillurbances which
happened at the Reformation, and of which a particular
account is given under the article SCOTLAND, it nas
enabled, that the figure of St Giles fiiould be cut out
of the town ftandard, and that of a thiille inferted m its
place. It was likewife enafted, that none but thofewho
profeffed the reformed religion Ihould ferve in any office
whatever *, and the better to preferve the extraordinary
appearance of fanftity which was affecled, a pillar was
erefted in the North Loch, for the purpofe of ducking
fornicators.
In 1595) the boys of the High School rofe agamit
their mafters j and fuch was the barbarifm of thofe
days, that one of thefe ftriplings.ihot a magiftrate with
a piilol, who had come along with the reft to reduce
them to obedience. "I he reafon of the uproar was,
that they were in that year refufed two vacations,
which had been cuftomary in former times : however,
they were at laft obliged to fubmit, and ever fince have
been allowed one for about fix weeks in the autumn.
The fame year the houfe of one of the bailies was af-
faulted by the tradefmen’s fons, aflifted by journeymen
who had not received the freedom of the town.; he
efcaped with his life, but the offenders were baniflitd
14 the city for ever.
Difturban- In the beginning of the reign of Charles I. a per-
ces-in the harmonv’feems to have fubfifted between the court
Charles I and the city Edinburgh; for in 16 27 King Charles I.
prefented the city with a new fword and gown to be
worn by the provoft at the times appointed by his fa¬
ther James VI. Next year he paid a vifit to this ca¬
pital, and was received by the magiftrates m a moft
pompous manner ; but foon after this the difturbances
arofe which were not terminated but by the death of
that unfortunate monarch. Thefe commenced on an
attempt of Charles to introduce Epifcopacy into the
kingdom; and the firft ftep towards this was the erec¬
tion of the three Lothians and part of Berwick into
a diocefe, Edinburgh being the epifcopal feat, and the
church of St Giles the cathedral. An account of the
7 ] EDI
difturbance occafioned by the firft attempt to read the Edinburgh,
prayer book there, is given under the article Britain ;
but though the attempt was given over, the minds ot
the people were not to be quieted. Next winter they
reforted to town in fuch multitudes, that the privy-
council thought proper to publifh two a61s ; by one of
which the people were commanded, under fevere pe¬
nalties, to leave the town in 24 hours j and by the
other, the court of feflion was removed to Linlithgow.
The populace and their leaders were fo much enraged
by the latter, that Lord Traquair and fome ot the bi-
fhops narrowly efcaped with their lives ; and next year
(1638) matters became ftill more ferious. For now,
the king having provoked his fubje6fs throughout, all
Scotland with the innovations he attempted in religion,
Edinburgh was made the general place of rendezvous,
and the moft formidable affociations took place ; an
account of which has already been given under the ai-
ticle Britain. Each of the towns in Scotland had a
copy ; and that which belonged to Edinburgh, crowd¬
ed with 5000 names, is ftill preferved among the
records of the city. Notwithftanding this difagree-
merit, however, the king once more vifited Edinburgh
in 1641, and was entertained by the magiftrates at an
expence of 1 2,OOol. Scots. It does not appear that af¬
ter this the city was in any way particularly concerned
with the difturbances which followed either through¬
out the remainder of the reign of Charles I. the com-
monw ealth, or the reign of Charles II. In 1680 the
duke of York with his duchefs, the princefs. Anne;
and the whole court of Scotland, were entertained by.
the city in the Parliament Houle, at the expence ot
15,000!. Scots. At this time it is faid that the fchemt
of building the bridge over the North Loch was fill!
proje6ted by the duke. ; . 15
From the time that King James VI. paid his laft vi- Regulations -
fit to Edinburgh in 1618, till the time of the union mack by.^
in 1707, a confiderable number of private regulations^^,
were made by tbe magiftrates ; fome of them evident¬
ly calculated for the good of the city, others ftrongly
charaaeriftic- of that violent fpirit of fanaticifm which
prevailed fo much in the laft; century. Among the
former was an aff paffed in 1621, that the houfes, in-
ftead of being covered with ftraw or boards, Ihould.have
their roofs conftruaed of Hate, tiles, or lead. This aa
was renewed in 1667 5 and in 1668 an aa was paffed re¬
gulating their height alfo. By this they were reftrained
to five ftories, and the thicknefs of the wall determined
to be three feet at bottom. In 1684 a lantern with a.
candle was ordered to be hung out on the firft lloor ot
every houfe, in order to light the ftreets at night; and
there were two coaches with four horfes each ordered
to be bought for the ufe of the magiftrates ; but it
does not appear how long they continued to be u.fed.
In 1681 the court of feftion difeontinued its fittings
in fummer : but as this was found to be attended with
inconvenience, an aa was paffed for their reftoration,
which has continued ever fince. During the time of
the civil war in 1649, t^ie was vidted> by the
plague, which is the laft time that dreadful diftemper
hath made its appearance in this country. The m-
feaion was fo violent, that the city was almoft de¬
populated, the prifoners were dilcharged from the
tolbooth, and an aa was made for giving one Dr
Joannes Politius a falary of 8cl. Scots per month, for
vifitmg
E I) I
[ 5i8 J
Edinburgh, vifiting tWe who were Sinfe&ed with the ditafe' Itf '
1677 tJle firft coffee houfes were allowed to be opened
but none without a licenfe : and the fame year the
town council regulated the price of penny weddings :
o.darning the men to pay no more than two killings,
^tel^tee!5 FriCeSha-
In ^ntradiffinaion to thefe falutary afts, we may
ffate thofe which fhmy an extravagant defire of prev
emng the appearance of virtue in the female fex, as
n 1. had been poffible for others to infpire them with
virtuous notions if they had not imbibed them of them-
lelves. In 1633 an aft of council was paffed, by which
women were forbidden to wear plaids over their faces,
under penalty of five pounds and the forfeiture of the
plaid for the firff fault. Banifhment was the punifli-
ment of the third. The reafon afligned for this ad was,
that matrons were not known from ffrumpets and loofe
women while the plaid continued to be worn over the
lace* I his act was renewed in 1637 and 1638. Suc¬
ceeding town councils continued to (how the fame re¬
gard to thefe matters 5 for in 1695 they enafted, that
EDI
16
Infamous
treatment
j » ' J J J j Ultit
mkeeper, vintner, or alefeller, fliould for the fu¬
ture employ women as waiters or fervants, under the
penalty of five (hillings iterling for each.
The following anecdote may perhaps make the vir-
tues of thefe legiflato™ themfelves wear a fufpicious
apect.^ In 1649 city having borrowed 40,000k
ucots, m order to raife their quota of men for his ma-
jeity, the payment of it was abfolutely refufed by the
town council when a demand was made for that pur-
pole. I hat they might not, however, depend entirely
upon their own opinion in a matter of fuch importance,
tiey took that of the General Affembly upon the
abject 5 and it was determined by thefe reverend di¬
vines, that they were not in confcience bound to pay
tor an unlawful engagement which their predeceffors
had entered into. But in 1652, Cromwell’s parliament,
V'o Pretended to no lefs fanCtity than they, declared
t lemielves of a very different opinion ; and on the ap-
th^fum1 0l °ne tllC Creditors» forced them to repay
The treatment which the brave marquis of Montrofe
of the rnar- ^ With, hkewife fixes an indelible ftigma both upon
quisof the magiitrates and clergy at that time. Having been
Montrofe. put under fentence of excommunication, no perfon was
allowed to (peak to him or do him the lead office of
fnendffiip. Being met without the city by the ma-
gikrates and town guard, he was by them conduded
in a kind of gloomy proceffion through the flreets
bareheaded, and in an elevated cart made for the pur-
poie; the other prifoners walking two and two before
him. At the time of his execution he was attended
hy one of the mmifters, who according to his own ac¬
count did not choofe to return till Zie hadfeen him cajlen
ever the ladder. J
The union in 1707 had almoft produced a war be¬
tween the two kingdoms which it wasidefigned to unite-
and on that occahon Edinburgh became a feene of tl^
moft violent diffurbances, of which a particular account
^ tinder tne article Britain*. During the time
the ad was paffing, it was found abfolutely neceffary
^or tne guards and four regiments of foot to do duty
in the city. The diffurbances were augmented by the
iiilagreement of the two members of parliament j and
4
notwithffanding the viclory gained at that time by the Edinburgh,
court party, Sir^ Patrick Johnfton the provoff, who' r—*
voted for the union, was obliged afterwards to leave
e country In 1715 the city remained faithful to Loyalty of
e royal cauie, and proper meaiures were taken for its the city in
detence. A committee of fafety was appointed, the l715 and
Clty guard increafed, and 400 men railed at theex-1^’
pence of the town. The trained bands likewife were
ordered out, 100 of whom mounted guard every night:
y which precautions the rebels were prevented from
attempting the city: they however, made themfelves
ma cr of the citadel of Leith 5 but fearing an attack
rom the duke of Argyll, they abandoned it in the
night time A fcheme was even laid for becoming
tTev6 brih i ^ °f which purpol
Tims f ^ ? NrjeauV° plaCe their baling ladders,
I hus feme of the rebels got up to the top of the walls
before any alarm was given j but in the mean time the
plot being difeovered by the ferjeant’s wife, her huffiand
was hanged over the place where he had attempted to
whirhTfi tH? u1?1 u The exPence of the armament
vhich the city had been at on this occafion amounted to
yew ^ 72I01* WhlCh WaS repaid by Kovernment in the
. Tbe loyalty of thls city was ftill farther remarkable
m the year 1725, when difturbances were excited in
ail parts Of the kingdom, particularly in the city of
Glalgow concerning the excife bill j for all remained
quiet m Edinburgh, notwithftanding the violent out¬
cries that were made elfewhere j and fo remarkable was
the tranquillity in the metropolis, that government af¬
terwards returned thanks to the magiftrates for it. In
1 j ’ 1lowever’ tile city liad again the misfortune to fall
uiider the royal difpleafure, on the following account.
I wo (mugglers having been detefted in dealing their
own goods out of a cuftomhoufe, were condemned to
be hanged. The crime was looked upon as trivial:
and therefore a general murmur prevailed among the
populace, which was no doubt heightened by the fol- l8
lowing accident. At that time it had been cuffomary Captain
tor perions condemned to die to be carried each Sun- P°rteous
day to the church, called fforn that circumftance theexecuted b7
10lbooth church.' The two prifoners juft mentioned a mob‘
were conducted m the ufual way, guarded by three
loidiers, to prevent their making their efcape ; but ha¬
ving once gone thither a little before the congrega¬
tion met, one of the prifoners feized one of the guards
m each hand, and the other in his teeth, calling out
to his companion to run 5 which he immediately did
with fuch fpeed, that he foon got out of fight, and
was never heard of afterwards. The perfon who had
thus procured the life of his companion without re-
garci to his own, would no doubt become a general ob-
ject of compaffion j and of courfe, when ^led to the
place of execution, the guard were feverely pelted by
the mob, and fome ol them, according to the teftimony
of the witneffes who were fwom on the occafion, pretty
much wounded. By this Captain Porteous, who
commanded the guard, was fo much provoked, that he
gave orders to fire, by which fix people w-ere killed
and eleven wounded. The evidence, however, even
of the fact that the orders to fire were given, anpears
not to have . been altogether unexceptionable 5 never-
thelefs, on this he was tried and condemned to be exe¬
cuted. At that time the king was abient in Hanover,
bavin?
EDI [ 5>
Edinburgh, having left the regency in the hands of the queen ; and
' r ’ the cafe of the unfortunate Porteous having been re-
prefented to her, fhe was pleafed to grant him a re¬
prieve : but fuch was the inveteracy of the people
againft him, that they determined not to allow him to
avail himfelf of the royal clemency. On the night pre¬
vious to the day that had been appointed for his execu¬
tion, therefore, a number of people affembled, fhut the
gates of the city, and burnt the door of the prifon, the
fame which the mob would formerly have broken open
in order to murder King James. They then took out
Porteous, whom it was found impoffible to refcue out of
their hands, though every method that the magiftrates
could take for that purpofe in fuch a confufion was made
ufe of. It was even proved, that the member of par¬
liament went to the commander in chief, and requeiled
that he would fend a party of foldiers to quell the dif-
turbance, but was abfolutely denied this requeft, becaufe
he could not produce a written order from the proyoft to
this purport; which, in the confufion then exiftmg m
the city, could neither have been expeaed to be given
by the provoft, nor would it have been fafe for any
perfon to have carried it about him. 1 hus the unhap¬
py viaim was left in the hands of his executioners
and being dragged by them to the place dc limed for re¬
ceiving his fate, was hanged on a dyer’s iign poll. As
they had not brought a rope along with them, they
broke open a {hop where they knew they were to be
had *, and having taken out what they wanted, left the
money upon the table, and retired without committing
19 any other diforder.
Govern- Such an atrocious infult on government could not
ment high- but be highly refented. A royal proclamation was if-
InThaTS fued, offering a pardon to any accomplice, and a reward
count. of 200I. to any perfon who would difcover one of
thofe concerned. The proclamation was ordered to be
read from every pulpit in Scotland the firll Sunday of
every month for a twelvemonth : but fo divided were
the people in their opinions about this matter, that ma¬
ny of the clergy hefitated exceedingly about complying
with the royal order, by which they were brought in
danger of being turned out of their livings j while thofe
who complied were rendered fo unpopular, that their
Situation was rendered {till worfe, than the others.
All the efforts of government, however, were infufh-
cient to produce any difcovery $ by which, no doubt,
the court were {fill more exafperated 5 and it was now
determined to execute vengeance on the magiftrates
and city at large. Alexander Wilfon, the provoft
at that time, was imprifoned three weeks before he
could be admitted to bail ; after which, he and the
four bailies, with the lords of jufticiary, were order¬
ed to attend the houfe of peers at London. On
their arrival there, a debate enfued, whether the. lords
{hould attend in their robes or not ? but at laft it was
agreed, that they fhould attend in their robes at the
bar. This however, was refufed by . their lordftiips,
who infilled that they fhould be examined .within the
bar '■) upon which the affair of their examination was
dropped altogether. A bill at laft paffed both, houfes,
by w7hich it was enabled, that the city of Ldinburgh
fhould be fined in 2000I. for the benefit of Porteous’s
widow (though fire was prevailed upon to accept of
1500I. for the whole) j and the provoft was declared
incapable of ever ferving government again in any
9 ] EDI
capacity whatever. To prevent fuch cataftrophcs in tnue ^ ‘h-kur£ ,
coming, the town council enabled, that, on the firft
appearance of an infurreftion, the chief officers in the
different focieties and corporations {hould repair to the .
council to receive the orders of the magiftrates for the
quelling of the tumult, under the penalty of 81. 6s. 8d.
for each omiffion. 20
In 1745, the city wa, inveiled by the U-^nder s The eny
army ; and on the 17th of September, the Nether bow the rebels
gate being opened to let a coach pafs, a party of high-jn
landers, who had reached the gate undifeovered., rulh-
ed in, and took poffeflion of the city. I he inhabi¬
tants were commanded to deliver up their arms at the
palace or Holyroodhoufe } a certain quantity of mili¬
tary {lores was required from the city, under pain of
military execution •, and an afleffment of 2s. 6d.. upon
the pound was impofed upon the real rents within the
city and liberties for defraying that expence.
The Pretender’s army guarded all the avenues to the
caftle ; but no figns of hortilities .enfued till the 25th of
the month, when the garrifon being alarmed from fome
unknowm caufe, a number of cannon were dneharged
at the guard placed at the Weft Port, but with very
little effedl. This gave occafion to an order to the
guard at the Weigh-houfe, to prevent all intercourfe
between the city and caftle } and then the governor
acquainted the provoft by letter, that unlefs the com¬
munication was preferved, he wrould be obliged to dif-
lodge the guard by means of artillery. A deputa¬
tion vTas next fent to the Pretender; acquainting him
with the danger the city was in, and entreating him to
withdraw the guard. With this he refufed to comply y
and the highland centinels firing at fome people who
were carrying provifions into the caftle, a pretty fmart
cannonading enfued, which fet on fire feveral houfes,
killed fome people, and did other damage, I he Pre¬
tender then confcnted to difmifs the guard, and the
cannonading ceafed. After the battle of Culloden,
the provoft of Edinburgh was obliged to ftand a very-
long and fevere trial, firil at London and then at Euin-
burgh, for not defending the city againft the rebels j
which, from the fituation and extent of the walls, every
One muft have feen to be impoflible.
During this trial a very uncommon circumftance hap¬
pened 5 the jury having fat two days, infilled that they
could fit no longer, and prayed for a ftiort refpite. As
the urgency of the cafe was apparent, and both parties
agreed^ the court, after long reafoning adjourned till
the day following, taking the jury bound under a pe¬
nalty of 500I. each ; when the court continued fitting,
two days longer, and the jury were one day enclofed.
The event was, that the provoft was exculpated.
After the battle of Culloden the duke of Cumber¬
land caufed fourteen of the rebel ftandards to be burn¬
ed at the crofs •, that of the Pretender was carried by the
common executioner, the others by chimney-fweep-
ers the heralds proclaiming the names of the com¬
manders to whom they belonged as they were thrown
into the fire. At this time the city of Edinburgh felt
a temporary inconvenience from the eledlion of their 2I
magiftrates not having taken place at the ufual time ; Govern-
fo that it became neceffary to apply to his majefty ment of the
for the reftoration of the government ot the city. This city reilor-
was readily granted, the burgeffes being allowed a polle
tax ; after which an entire new fet of magiftrates was
rptnrnefi..
S3 2
Salary be
flowed on
EDI [ 5ao ]
Edinburgh returned, all of them friends to the houfe of Hanover j quartered
^ and foon after the freedom of the city in a gold box
was prefented to the duke of Cumberland.
With thele traniaftions all interferences betwixt go¬
vernment and the metropolis of Scotland were ended j
the reil of its hiltory therefore only confifts of inter¬
nal occurrences, the regulations made by its own ma-
giftrates for the benefit of the city, their applications
to government for leave to improve it, or the execution
of thefe improvements } of which we fhall now give a
brief detail.
In the year 1716, the city fisft bellowed a fettled fa-
the provoft. ^ary on Prov°ft> in order to enable him to fupport
the dignity of the firft magiftrate. This was at firlt 300I5
but has lince been augmented to 5O0I. which his
lordfhip Hill enjoys. In 1718 it was recommended to
the magiftrates to diftinguifh themfelves by wearing
coats of black velvet, for which they were allowed
10I. but this aft being abrogated in 1754, gold chains
•were affigned as badges of their office, which they
continue to wear. Provoft Kincaid happened to die in
office in the year 1777 ; which being a very rare
accident, perhaps the only one of the kind to be met
with in the records of Edinburgh, he was buried
with great folemnity, and a vaft concourfe of people
23 attended.
Account of Tumults have been frequent in Edinburgh, chiefly on
account of the dearnefs of proviflons. 101740 Bell’s
mills were firft attacked by the populace, and afterwards
Leith mills; nor could the rioters be difperfed till the mi -
litary had fired among them and wounded three, of whom
E D I
in the caflle to his affiiiance.
night a party of rioters let out for Ford.
tumults.
one died 5 and it was found neceflary to order fome dra¬
goons into the city in order to preferve tranquillity. In
1742, another violent tumult took place, owing to a cu-
ftom of Healing dead bodies from their graves for anato¬
mical purpofes, which had then become common. The
populace beat to arms, threatened deftruftion to the bur¬
geons 5 and, in fpite of the efforts of the magiftrates,
demoliffied the houfe of the beadle at St Cuthbert’s.
In 1756 new difturbances, which required the affift-
ance of the military, took place : the caufe at this
time was the impreffing of men for the war which was
then commencing. A difturbance was likewife excited
in 1760. This was occafioned by the footmen, who
till then were allowed to follow their mafters into the
playhoufe, and now took upon them to difturb the en¬
tertainment of the company j the confequence of which
was, that they were turned out, and have ever ftnce
been obliged to wait for their mafters. In 1763 and
1765, the tumults on account of the price of provi-
ftons were renewed 4 many of the mealmongers had
their houfes broken open and their ffiops deftroyed.
The magiftrates, as ufual, were obliged to call in a
party of dragoons to quell the difturbance ; but at the
fame time, to put an effeftual flop, as far as was in their
power, to thefe proceedings for the future, they gave
fecurity, that people w-ho brought grain or provifion
into the market ffiould be fecured m their property.
Since that time there have been no tumulrs direftly on
the account of provilions ; though in 1784 a terrible
riot and attack of a diftillery at Canonmills took place,
on a fuppolition that the diftillers enhanced the price
of meal by ufing unmalted grain. The attack was re¬
pelled by the fervants of the diftillery; but the mob
cquld not be quelled until the fheriff called the foldiers
3
The fame Edinburgh*
a place ten y—
miles to the foutlrward, wffiere there was likewife a
large diftillery 5 which, as there was none to make any
pppofition, they foon deftroyed. One man was killed
in this riot at Edinburgh by the fire of a fervant of the
diftillery, and feveral of the rioters were aftemards
fecured and puniftied.
In the years 1778 and 1779 two very alarming di¬
fturbances happened, which threatened a great deal of
bloodffied, though happily they were terminated with¬
out any. The firft was a mutiny of the earl of Sea-
forth’s Highland regiment, who were at this time quar¬
tered in the caftle. Thefe having been ordered to em¬
bark, for fome ;eafon or other unanimoufly refufed, and
polled themfelves on the top of Arthur’s feat, where
they continued for two days. Troops were collefted to
prevent their efcape, and the inhabitants were ordered
to keep within doors at the firft toll of the great bell,
which wras to be a lignal of violence about to take
place } but fortunately all the fears, naturally arifing
• from the expeftation of this event, wrere diffipated by an
accommodation. The other happened on account of the
attempt to repeal the penal laws againft the Papifts j
and was much more alarming than the. other, as being
the effeft of a premeditated fcheme and determined re-
folution to oppofe government. On the 2d of Febru¬
ary 1779 a mob affembled in the evening, burned a
Popiffi chapel, and plundered another. Next day they
renewed their depredations ; deftroying and carrying
off' the books, furniture, &c. of feveral Popiffi priefts
and others of that perfuafion. The riot continued all
that day, though the affiftance of the military was
called in j but happily no lives were loft, nor was there
any firing. The city was afterwards obliged to make
good the damage fuftained by the Catholics on this
occafion, which was eftimated at 1500I. This year
alfo an unlucky accident happened at Leith. About
50 Highland recruits having refufed to embark, a par¬
ty of the South Fencibles was fent to take them pri-
foners. Unexpectedly, however, the Highlanders flood
upon their defence *, when, after fome words, a firing
commenced on both fides, and about one half of the
Highlanders were killed and wounded, the remainder
being taken prifoners and carried to the caftle. Captain
Mansfield and two or three privates were killed in this
affray. . > # 24
We ffiall clofe this hiftory of Edinburgh with a ge-General
neral account of the improvements which have lately tuftory of
taken place in it, and of which a particular defcription 1 ^ im~
will afterwards be given. Thefe began in the year*>r°vemen
1753, when the foundation-ftone of the Exchange
was laid, at which time there was a grand proceffion,
and the greateft concourfe of people ever known in
Edinburgh. A triumphal arch was eroded for the
purpofe, through which the proceffion paffed, and me¬
dals were fcattered among the populace. In 1756 the
high ftreet was cleared by the removal of the crofs j
though many regretted this, on account of its being a
very ancient and elegant building. In the middle it
had an unicorn placed on the top of a pillar 20 feet
high 3 but this fine ornament was broken to pieces by
the giving way of the tackle by which it was attempt¬
ed to remove it. It is now again ereded at Drum, a
feat formerly belonging to Lord Somerville, about four
miles •
EDI [ 5
Edinburgh miles from Edinburoli. In 1763 the firft ftone of the
'' v— North bridge was laid by Provoft Drummond ; and in
1767 an adt of parliament was obtained for extending
the royalty of the city over the fields to the north-
ward, where the New Town is now fituated. About
the fame time a fpot of ground upon the fouth fide of
the town was purchafed by a private perfon for 12001.
which being feued out for building, gave rile to the
increafe of the town on that quarter ; and this pro¬
ceeded the more rapidly, as the houfes built there were
free from the dues im poled upon others fubject to the
royalty. In 1774 the foundation of the Regiiler Of¬
fice was laid. In 1784 the projedt for rendering the
accefs to the town equally eafy on both fides was be¬
gun to be put in execution by laying the foundation of
the South bridge. At the fame time a great improve¬
ment was made by reducing the height of the llreet
feveral feet all the way from the place where the crofs
flood to the Netherbow; by which means the afcent
is rendered more eafy, not only for carriages, but alfo
for perfons w'ho walk on foot. At the fame time, the
flreet was farther cleared by the removal of the town
guard houfe, which had long been complained of as an
encumbrance. Within thefe three years (1805) part
of the Luckenbooths has been removed, and it is Hill far¬
ther in contemplation to remove the whole with the
prifon. When this is accomplilhed, with other im¬
provements by which it mult neceffarily be accom¬
panied, it is to be queltioned whether any city in Bri¬
tain w ill be able to vie with Edinburgh in elegance and
beauty.
Having thus given a concife hiltory of the city from
its earlieit foundation, we lhall now proceed to defcribe
it in its molt improved Hate.
*S . Edinburgh is fituated upon a lleep hill, rifing from
ofEdm-1011 ea^ to welt, and terminating in a high and inacceffible
rock, upon which the cattle Hands. At the ealt end
or lower extremity of this hill Hands the abbey of
Holyroodhoufe, or king’s palace, diflant from the
caHle upwards of a mile 5 and betwixt which, along
the top of the ridge, and almoit in a Hraight line, runs
the high Hreet. On each fide, and parallel to this
'<n’dge or hill, is another ridge of ground lower than
that in the middle, and wdfich does not extend fo far
to the eafi 5 that on the fouth being intercepted by Sa-
lilhury rocks and Arthur’s feat, a hill of about 800
feet of perpendicular height •, and that on the north by
the Calton hill, confiderably lower than Arthur’s feat :
fb that the fituation of this city is mofl lingular and
romantic ; the ealt or lower part of the town lying be¬
tween two hills *, and the welt or higher part rifing up
towards a third hill, little inferior in height to the high-
eft of the other two, upon which, as has been obferved,
the caflle is built, and overlooks the town.
The buildings of the town terminate at the diflance
of about 200 yards from the cafile gate $ which fpace
affords a moH delightful as well as convenient and
healthful walk to the inhabitants. The profpebt from
this fpot is perhaps the fineff anywhere to be met with,
for extent, beauty, and variety.
In the valley or hollow betwixt the mid and the fouth
ridges, and nearly parallel to the high Hreet, is another
Hreet called the Cowgate 5 and the town has now ex-
-tended itfelf over moH part of that fouth ridge alfo,
Vol. VII, Part II,
burgh.
21] EDI
Betwixt the mid and the north ridges was a loch, which, Edinburgh.,
till of very late, terminated the town on that fide. From -
the high Hreet towards the loch on the north, and
Cowgate on the fouth, run narrow crofs flreets or lanes,
called wynds and ciofes, which grow fleeper and deeper
the farther welt or nearer the caitle } fo tuat, were it
not for the clofenefs and great height of the buildings,
this city, from its fituation and plan, might naturally be
expected to be the beff aired, as well as the cleaneff, in
Europe. The former, notwithffanding thefe difad-
vantages, it enjoys in an eminent degree } but we can¬
not compliment it upon the latter, notwithflanding every
poflible means has been ufed by the magiitrates for that
purpofe.
The Heepnefs of the afcent makes the accefs to tne
high Hreet from the north and fouth very difficult
which no doubt greatly retarded the enlargement of
the city. To remedy this inconvenience on the north,
and with a view to extend the town on that quarter, a
molt elegant bridge has been thrown over the North
Loch, which joins the north ridge to the middle of the
high flreet, by fo eafy an afcent as one in fixteen ;
and in purfuance of the defign, a plan of a new town
to the north was fixed upon, and is now nearly finifhed,
with an elegance and tafle that does honour to this
country. In like manner, to facilitate the accefs from
the fouth fide, a bridge has been thrown over the val- *
ley through which the Cowgate runs ; which, if not
equally elegant with the North bridge, is certainly as
convenient. 26
The gradual increafe of the city of Edinburgh may Account of
in fome degree be underflood from the traces of its an-if6 gradual,
cient walls that Hill remain. James II. in 1450, hrfl
bellowed on the community the privilege of fortify¬
ing the city with a wall, and empowered them to levy
a tax upon the inhabitants for defraying the expence.
When the city was firff fortified, the wall reached no
further than the prefent water-houfe, or refervoir, on
the cafile hill : from thence to the foot of Halker -
flon’s wynd, jufl below the new bridge, the city wTas
defended by the North Loch ; an inconfiderable morafs,
which, being formerly overflowed, formed a fmall lake
that hath fince been drained. From this place to the
foot of Leith wynd, it does not appear how the city
was fortified ? but from the foot of Leith wTynd to the
Nether-bow port it was defended only by a range of
houfes 5 and when thefe had became ruinous, a wall was
built in their place. The original wall of Edinburgh,
therefore, began at the foot of the north-eafl rock of
the caflle. Here it was Hrengthened by a fmall fortrefs,
the ruins of which are Hill to be feen, and are called the
Wei/-houfe Tower, from their having a fpring in their
neighbourhood. When the wall-came oppolite to the
refervoir, it w’as carried quite acrofs the hill, having a
gate on the top for making a communication between
the town and caflle. In going down the hill, it went
flanting in an oblique direction to the firfi angle in
going down the Wefl-bow, where was a gate named
the Ufiper-bbw Port, one of the hooks of which Hill
remains. Thence it proceeded eaflward in fuch a man¬
ner, as would have cut off not only all the Cowgate,
but fome part of the parliament houfe } and being con¬
tinued as far as the Mint clofe, it turned to the north-
eafl, and connected itfelf with the buildings on the
3 .U north
EDI [52
J^inbnrgh. north fide of the high ftreet, where was the original
c—■“V'—^ Nether-bo%v Port, about 50 yards well from that which
afterwards went by the fame name.
Soon after the building of this wall, a new ftreet
was formed on the outfide of it, named the Cowgate,
which in the 16th century became the refidence of the
nobility, the fenators of the college of juftice, and other
perfons of the firft diftindtion. After the fatal battle
of Flowden, however, the inhabitants of the Cowgate
became very anxious to have themfelves defended by
a wall as well as the reft. The -wall of the city was
therefore extended to its prefent limits. This new
wall begins on the fouth-eaft fide of the rock on which
the caftle is built, and to which the town wall comes
quite clofe. From thence it defcends obliquely to the
Weft Port • then afcends part of a hill on the other
fide, called the High Riggs; after which, it runs eaft-
ward with but little alteration in its courfe, to the
Brifto and Potter-row ports, and from thence to the
Pleafance. Here it takes a northerly direclion, which
it keeps from thence to the Cowgate port 5 after which
the enclofure is completed to the Nether-bow by the
houfes of St Mary’s wynd. The original Nether-bow
port being found not well adapted for defence was
pulled down, and a new one built in ij’yi by the ad¬
herents of ^)ueen Mary. In 1606, the late hand-
fome building was eredted about 50 yards below the
place where the former flood. It was two ftories high,
and had an elegant fpire in the middle 5 but being
thought to encumber the ftreet, and the whole build¬
ing being in a crazy fituation, it was pulled down by
order of the magiftrates in 1764.
In the original wall of Edinburgh there was, as has
been already obferved, a port on the Caftle hill. On
the extenfion of the wall, after building the houfes in
the Cowgate, this gate was pulled down. That in the
upper or Weft-bow flood for a much longer time, and
was pulled down within the memory of fome perfons
lately or perhaps ftill living. Befides thefe, there was
a third, about 50 yards above the head of the Canon-
gate 5 but whether there were any more, is uncertain.
The ports or gates of the new walls were, 1. The IVe/h
Port, fituated at the extremity of the Grafs Market;
beyond which lies a fuburb of the town and a borough
of regality, called Portjburgh. Next to this is a wicket,
ftruck out of the town wrall in 1744, for the purpofe
of making an eafier communication between the town
and the .public walks in the meadows, than by Brifto
port. The next to this wras Brijio Port, built in 1515 ;
beyond which lies a fuburb called Briflo Street. At a
fmall diftance from Brifto was the Potter-row Port, which
took this name from a manufactory of earthen ware in
the neighbourhood. Formerly it was called Kirk of
Field Port. Between this and the Cowgate port flood
another, called St Mary's Wynd Port, which extended
from eaft to weft acrofs the foot of the Pleafance, and
which was demolithed only fince the middle of the laft
century. Clofe to the middle of this flood the Cotv-
gate Port ; which opened a communication between the
Cowgate and St Mary’s wynd, and the Pleafance.
The Nether-how Port has been already fpoken of. At
the foot of Leith wynd was another gate, known by
the name of Leith Wynd Port; and within it was a
wicket giving accefs to the church of Trinity College,
and which ftill remains. At the foot of Halkerfton’s
1
EDI
^.nd was another, which, as well as the former, was Edinburgh,
built about the year 1560. Both of thefe were pulled —-y—
down fome years ago, and all the reft in 1785. Ano¬
ther ftill remains at the foot of the Canongate, known
by the name of the Watergate.
For 250 years the city of Edinburgh occupied the
fame fpace of ground, and it is but very lately that its
limits have been fo confiderably enlarged. In the
middle of the 16th century, it is defcribed as extending
in length about an Italian mile, and about half as much
in breadth ; which anfwers very nearly to its prefent
limits, the late enlargements only excepted. This fpace
of ground, however, was not at that time occupied in
the manner it is at prelent. The houfes were neither
fo high nor fo crowded upon each other as they are now.
This was a confequence of the number of inhabitants
mcreafing, which has occafioned the raifing of the
houfes to luch a height as is perhaps not to be paral¬
leled in any other part of the world. Till the time of
the Reformation, the burying ground of the city
extended over all the fpace occupied by the Par¬
liament fquare, and from thence to the Cowgate.
£ he lands lying to the fouthward of the Cowrgate were
chiefly laid out in gardens belonging to the convent of
Black friars, and the church of St Mary in the Field.
Thefe extended almoft from the Pleafance to the Pot-
terrow port. From the Brifto to the Weft port the
ground was laid out in gardens belonging to the Gray
friars. The magiftrates, on their application to Queen
Mary, obtained a grant of the Gray friars gardens for a
burying place j for which it was given as a reafon, that
they were fomewhat diftant from the town. Here,
however, it muft be underftood, that thefe gardens
were diftant from the houfes, and not without the
walls 5 for they had been inclofed by them long be¬
fore. In the time of James I. the houfes within the
walls feem to have been in general, if not univerfal-
ly, covered with thatch or broom j and not above
20 feet high. Even in the year 1621, thefe roofs
were fo common, that they were prohibited by aft
of parliament, in order to prevent accidents from fire.
In the middle of the laft century, there were nei¬
ther courts nor fquares in Edinburgh. The Parlia¬
ment clofe or fquare is the oldeft of this kind in the
city. Miln’s fquare, James’s court, &c. were built
long after ; and Argyll’s and Brown’s fquares about
the years 1750 or 1760.
The New Town was projefted in the year 1752
but as the magiftrates could not then procure an ex-Town,
tenfion of the royalty, the execution of the defign was
fufpended for fome time. In 1767, an aft was ob¬
tained, by which the royalty was extended over the
fields to the northward of the city ; upon which ad-
vertifements were publiftied by the magiftrates, de¬
firing proper plans to be given in. Plans were given
in accordingly, and that defigned by Mr James Craig
architeft was adopted. Immediately afterwards, peo¬
ple were invited to purchafe lots from the town coun¬
cil ; and fuch as purchafec! became bound to conform
to the rules of the plan. In the mean time, however,
the town council had fecretly referved to themfelves a
privilege of departing from their own plan j which
they afterwards made ufe of in fuch a manner as pro¬
duced a law fuit. According to the plan held forth
to the purchafers, a canal was to be made through that
place
EDI
t
Edinburgh, place where the North Loch had been, and the bank on
l'   ' the north lide of it laid out in terraces : but inftead
of this, by an aft of council, liberty was relerved to
the town to build upon this fpot j and therefore, when
many gentlemen had built genteel houfes in the new
town on faith of the plan, they were furprifed to find
the fpot appointed for terraces and a canal, beginning
to be covered with mean irregular buildings, and
work houfes for tradefmen. This deviation was im¬
mediately complained of j but as the magiftrates {bow¬
ed no inclination to grant any redrefs, a profecution
was commenced again it them before the Lords of Sef-
fion. In that Court the caufe was given againft the
purfuers, who thereupon appealed to the Houle of
Lords. Here the fentence of the Court of Seffion was
reverfed, and the caufe remitted to the confideration
of their Lordihips. At laft, after an expenfive con-
teft, matters were accommodated. The principal
term of accommodation was, that fome part of the
ground was to be laid out in terraces and a canal $
but the time of difpofing it in that manner, was refer¬
red to the Lord Prefident of the Court of Seflion and
the Lord Chief Baron of the Exchequer. The fall
of part of the bridge, hereafter mentioned, proved a
very confiderable diiadvantage to the New Town j as it
neceffarily induced a fufpicion that the paffage, by
means of the bridge, could never be rendered fafe.
An overfight of the magiftrates proved of more elfen-
tial detriment. A piece of ground lay to the fouth-
ward of the Old Town, in a fituation very proper for
building. This the magiftrates had an opportunity
of purchafing for 1 200I j which, however, they ne-
glefted, and it wras bought by a private perfon, who
immediately feued it out in lots for building, as has
been already mentioned. The magiftrates then began
to fee the confequence, namely, that this fpot being
free from the duties to which the royalty of Edinburgh
is fubjeft, people would choofe to refide there rather
than in the New Town. Upon this they offered the
purchafer 2000I. for the ground for which he had paid
1200I. j but as he demanded -20,000!. the bargain
Bid not take place. Notwithftanding thefe difcourage-
ments, the New Town is now almoft finiihed j and
from the advantages of its fituation, and its being built
according to a regular plan, it hath undoubtedly a fupe
riority over any city in Britain. By its fituation, how¬
ever, it is remarkably expofed to ftorms of wind, which,
at Edinburgh, fometimes rage with uncommon violence.
It has three ftreets, almoft a mile in length, running
from eaft to weft, interfefted -with crofs ftreets at proper
diftances. The moft northerly, called -Queen's Street,
till lately that Heriot row was built, is 100 feet broad,
and commands an extenfive profpeft of the Forth, the
county of Fife, and the {hipping in the river. That
called George's Street, which is in the middle, is no lefs
than 115 feet wide. It is terminated at each end by
two very elegant and extenfive fquares ; that on the eaft
end is called St Andreve's Square; the other, which is
not yet finiihed, is called Charlotte's Square. Prince’s
ftreet is the moft foutherly; and extends from the
northern extremity of the bridge, quite to the weft end
ol the town. It has only been finifhed this year (1805).
From the -weft end of Prince’s ftreCt, a fpacious road
has been lately opened to join the two roads to Glaf-
523 ] EDI
gow by Airdrie and Whitburn. This has greatly xm- EJinburglu
proved the approach to the town from the weft.
The moft remarkable public buildings in Edinburgh
are— ?8
I. The Cajlle. This {lands on a high rock, acceflible Public
only on the eaft fide. On all others it is very fteep, and
in fome places perpendicular. It is about 300 feet high
from its bafe : fo that, before the invention of artillery,
it might well have been deemed impregnable 5 though
the event {bowed that it was not. The entry to this
fortrefs is defended by an outer barrier of pallifadoes j
within this is a dry ditch, drawr-bridge, and gate, de¬
fended by two batteries which flank it j and the whole
is commanded by a half-moon mounted with brafs
cannon, carrying balls of 12 pounds. Beyond thefe
are two gate-ways, the firft of which is very ftrong,
and has tivo portculifies. Immediately beyond the fe-
cond gate way, on the right hand, is a battery mount¬
ed with brafs cannon, carrying balls of 12 and 18
pounds weight. On the north fide are a mortar and
fome gun batteries. The upper part of the caftle
contains a half-moon battery, a chapel, a parade for
exercife, and a number of houfes in the form of a fquare,
which are laid out in barracks for the officers. Be-
fides thefe there are other barracks fufficient to con¬
tain 1000 men; a powder magazine, bomb proof; a
grand arfenal, capable of containing 8000 ftand of
arms; and other apartments for the fame ufe, which
can contain 22,000 more : fo that 30,000 ftand of
arms may be conveniently lodged in this caftle, On
the eaft fide of the fquare above mentioned, were for¬
merly royal apartments , in one of which King James
VI. was born, and which is ftill fliown to thofe who
vifit the caftle. In another, the regalia of Scotland
w’ere depofited on the 26th of March 1707 , but as
they were never fhown to any body, a fufpicion has
arifen that they wTere carried to London, perhaps du¬
ring the rebellions 1715 or 1745. This apartment was
opened in 1794 by an order from government, in pre¬
fence of the firft civil officers of the crown, as the lord
prefident of the court of feffion, the lord juftice clerk,
&c. but no part of the regalia wras found.
The governor of the caftle is generally a nobleman,
wffiofe place is worth about 1000I. a-year j and that of
deputy governor, 500I. This laft refides in the houfe ap¬
pointed for the governor, as the latter never inhabits it.
There is alfo a fort-major, a ftore-keeper, mafter gunner,
and chaplain ; but as this laft does not refide in the caftle,
worlhip is feldom performed in the chapel. The parlia¬
ment houfe was formerly included in the great fquare
on the top, and the royal gardens -were in the marflx
afterwrards called the North Loch ; the king’s {tables be¬
ing on the fouth fide, where the houfes ftill retain the
name, and the place where the barns were ftill retain
the name of Caftlebarns.
The caftle is 'defended by a company of invalids, and
four or five hundred men belonging to fome marching
regiment, though it can accommodate 1000, as above
mentioned 5 and this number has been fometimes kept
in it. Its natural ftrength of fituation was not fufticient
to render it impregnable, even before the invention of
artillery, as wTe have already obferved 5 much lefs would
it be capable of fecuring it againft the attacks of a mo¬
dern army well provided with cannon. It could not, in
3 U 2 all
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Edinburgh- all probability, withftand, even for a few hours, a well
* diretted bombardment: for no part but the powder
magazine is capable of refilling thefe dellruCtive ma-
cnines j and the Iplinters from the rock on which the
caftle is built, could not fail to render them ftill more
formidable. Befides, the water of the well, which is
very bad, and drawn up from a depth of 100 feet, is
apt to fubfide on the continued difcharge of artillery,
which produces a concufiion in the rock.
2. T/ie Palace of Holy roodhoufe. This, though much
neglected, is the only royal habitation in Scotland
that is not entirelyun ruins. It is a handfome fquare of
230 feet in the infide, furrounded with piazzas. The
front, facing the well, confills of two double towers
joined by a beautiful low building, adorned with a
double baluftrade above. The gate-way in the middle
is decorated with double Hone columns, fupporting a
cupola in the middle, reprefenting an imperial crown,
with a clock underneath. On the right hand is the
great ftaircafe which leads to the council chamber and
the royal apartments. Thefe are large and fpacious, but
unfurniflied : in one of them the Scotch peers meet to
eledl 16 of their number to reprefent them in parliament.
The gallery is on the left hand, and meafures 1 <;o feet by
27 b. It is adorned with the fuppofed portraits of all the
kings of Scotland. In the apartments of the duke of
Hamilton, which he poffeffes as hereditary keeper of
the palace, Queen Mary’s bed of crimlbn damalk, bor¬
dered with green fringes and taffels, is Hill to be feen,
but almoll reduced to rags. Here alfo llrangers are
fhown a piece of wainfcot hung upon hinges^ which
opens to a trap flair communicating with the apart¬
ments below. Through this paffage Darnley and the
other confpirators rulhed in to murder the unhappy
Rizzio. Towards the outward door of thefe apart¬
ments are large dufky fpots on the floor, faid to be
occafioned by Rizzio’s blood, which could never be
■wafhed out. In the lodgings afligned to Lord Dun-
more is a piilure by Van Dyke, efleemed a maflcr-
ly performance, of King Charles I. and his queen go¬
ing a-hunting. There are like wife the portraits of
their prefent majeflies at full length by Ramfay. The
lodgings above the royal apartments are occupied by
the duke of Argyll as heritable mafler of the houfe-
hold.
The front of this palace is two fiories high ; the
roof flat j but at each end the front projedls, and is or¬
namented wuth circular towers at the angles. Here
the building is much higher, and the reft of the palace
is three fiories in height. The north-weft towers w'ere
built by James V. for his own refidence : his name is
flill to be feen below a niche in one of thefe towers.
During the minority of Queen Mary, this palace was
burned by the Englifh 5 but foon after repaired and
enlarged beyond its prefent fize. At that time it
conftiled of five courts, the moft wefterly of which
was the largefl. It was bounded on the call by the
front of the palace, which occupied the fame fpace it
does at prefent •, but the building itfelf extended fur¬
ther to the fouth. At the north-weft corner was a
ftrong gate with Gothic pillars, arches, and towers,
part of which was not long ago pulled down. Great
part of the palace was burnt by Cromwell’s foldiers j
but it was repaired and altered into the prefent form
after the Refloration. The fabric was planned by Sir
1 524 1
EDI
W illiam Bruce a celebrated architect, and executed Edinburgh,
by Robert Mylne mafon. The environs of the palace v—'
afford an afylum for infolvent debtors j and adjoin¬
ing to it is an extenfive park, all of which is a fanc-
tuary.
I he abbey church was formerly called the monajlery
of Holy roodhoufe, and built by King David I, in 1128.
He gave it the name of Holy roodhotife, in memory, as
is laid of his deliverance from an enraged hart, by the
miraculous interpofition oi a crois from heaven. This
monaltery he gave to the canons regular of St Auguf-
tine : on wdtom he alfo beitowred the church of Edin¬
burgh cartle, with thofe ol St Cuthbert’s, Corftorphin,
and Libberton, in the ihire of Mid Lothian, and of
Airth in Stirlinglhire ; the priories of St Mary’s I fie
in Galloway, of Blantyure in Clydefdale, of Rowadill
in Rofs, and three others in the Weftern Lies. To
them he alfo granted the privilege of ere£ting a bo¬
rough betwreen the town of Edinburgh and the church
of Holyroodhoufe. From thele canons it had the
name oi the Canongate, which it Hill retains. In this
new borough they had a right to hold markets. They
had alfo portions of land in different parts, with a moft
extenfive jurifdiclion, and right of trial by duel, and
fire and water ordeal. They had alfo certain re¬
venues payable out of the exchequer and ether funds,
with fiftiings, and the privilege of ere6ling mills
on the water of Leith, which ftill retain the name
of Canon mills. Other grants and privileges were be¬
llowed by fucceeding fovereigns •, fo that it was deem¬
ed the richeft religious foundation in Scotland. At
the Reformation, its annual revenues were 442 bolls
of wheat, 640 bolls of bear, 560 bolls of oats, 500
capons, twTo dozen of hens, as many falmon, 1 2 loads
of ialt; befides a great number of fwine, and about
250I. fterling in money. At the Reformation, the
fuperiority of North Leith, part of the Pleafance, the
barony of Broughton, and the Canongate, wTere veiled
in the earl of Roxburgh ; and wrere purchafed from
him by the town council of Edinburgh in 1636. In
1544, the church fuffered confiderably by the invafion
of the Engliih 5 but was fpeedily repaired. At the
Reftoration, King Charles II. ordered the church to be
fet apart as a chapel royal, and prohibited its ufe as a
common pariih church for the future. It was then fit¬
ted up in a very elegant manner. A throne was
erefted for the fovereign, and 1 2 Halls for the knights
of the order of the thiille :' but as mafs had been ce¬
lebrated in it in the reign of James VII. and it had
an organ, with a fpire, and a fine chime of bells on
the weft fide, the Preibyterians at the Revolution
entirely deftroyed its ornaments, and left nothing but
the bare wralls.—Through time, the roof of the church
became ruinous ; on which the duke of Hamilton re-
prefented its condition to the barons of exchequer, and
craved that it might be repaired. This requeft w^as
complied with : but the architect and mafon who were
employed, covered the roof wnth thick flag Hones,
which foon impaired the fabric 5 and on the 2d of
December 1768, the roof fell in. Since that time, no
attempt has been made to repair it, and it is now en¬
tirely fallen to ruin.
The ruins of this church, however, are flill fufficient
to difeover the excellency of the workmanfhip. Here
feme of the kings of Scotland are interred ; and an
odd
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[ 52S 3
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KoddUndofcu,^
counter^"? Roxburgh who died feveral hundred years
rpi r (• ’j to belon? to tne fortner were very
We and the latter had feme Aelh dried upon them.
Tlfe chapel was fitted up in the elegant manner above
mentioned by James VII. but fuch was the enthunafra
of the mob, that they not only deftroyed the orna¬
ments, but tore up even the pavement, which was of
m l^the eaftward of the palate is the bowling green
now entirely in diforder; and behind it is a held called 6/
Ami's Yards. Beyond this is a piece of ground called the
King's Park; which undoubtedly was formerly over¬
grown with wood, though now there is not a fingle
free in it. It is about three miles in circumference,
and was firft enclofed by James V. ^ J
rockv hills of Jtkuvr's Heat ana Salllhury Craigs,
which laft afford an inexhauftible flone quarryand up-
the north fide of the hill ftands an old ruinous cha¬
pel dedicated to St Anthony. The ftones are uled in
building as well as for paving theftreets and highways.
The park was mortgaged to the family of Haddington
for a^debt due to them; and by the prefent earl .
been divided into a number of enclofures by ilone dykes
ra“ed at a conliderable expence A good nurnbe „
iheep and feme black cattle are fed upon it, and
now rented at x cool, annually. . ,
- St Giles's Church, is a beautiful Gothic building,
meafuring in length 206 feet. At the weft end, its
breadth fs no ; in the middle, 129 •, and at the eaft
end 76 feet. It ha,s a very elevated fituation, and
Badofned with a lofty fquare tower • from thefides
and corners of which rife arches of figured ftone
work : thefe meeting with each other m the middle
complete the figure of an imperial crown, the top of
which terminates in a pointed fpire. Ihe whole heig 1
of this tow^er is x6x feet. , 1
This is the moft ancient church m Edinburgh. From
a paffage in an old author called Simeon Dunelmenfis,
foL conieclure it to have been built before the year
Bc4: but we do not find exprefs mention made of it
pefore x 3 59- The tutelar faint thlS \
Edinburgh, was St Giles, a native of Greece. He
lived in" the fixth century, and was defeended of an
illuftrious family. On the death of his parents,_ he
gave all his eftate to the poor ; and travelled into
France, where he retired into a wildernefs near the
conflux of the Rhone with the fea and continued there
three years. Having obtained the reputation of ex
traordinary fanaity, various miracles were attributed
to him ; and he founded a monaftery m Languedoc
known long after by the name of St Giles s.—ln the
reign of James II. Mr Prefton of Gorton, a gentleman
whofe defeendants ftill poffefs an eftate m the county
of Edinburgh, got poffefiion of the arm of this {am ,
which relick he bequeathed to the church of Edu -
burgh. In gratitude for this donation, the magiftrates
granted a charter in favour of Mr Prefton s heirs, y
which the neareft heir of the name of Prefton was en¬
titled to carry it in all proceflions At the am
time, the magiftrates obliged themfelves to fou
an altar in the church of St Giles’s, and appom a
chaplain for celebrating an annual mafs for the foul
Mr Prefton 3 and likewife, that a tablet, contain g
his asms, and an account of his pious
be put up in the chapel.—St Giles s was tin- 1 ‘
parllh church, of which the bilhop of Lmdisiarn 01 Ho¬
ly Ifland, in the county of Northumberland, was pa¬
tron. He was fucceeded in die patronage by the ab¬
bot and canons of Dunfermline, and they b> the ma¬
giftrates of Edinburgh. In 1466, it was ereHed into
^ collegiate church by James HI. At the Reforma-,
tion, the church was, for the greater convenience, di¬
vided into feveral parts. The four principal ones are
appropriated to divine worflup, the leffei_ ones to
other purpofes. At the fame time the religious uten-
fils belonging to this church were feized by the magi¬
ftrates. "They were,-St Giles’s arm, enfhrirmd m
filver, weighing five pounds three ounces and a half , a
filver chalice, or communion cup, weighing 23 ounces ,
the great euchari/l or communion cup, with golden weike
andjlcnes; two cruets of 25 ounces-, agolden bell, with a
heart, of four ounces and a half 3 a go den unicorn 3 a
golden pix, to keep the hoft 3 a fmall golden heait,
with two pearls 3 a diamond ring 3 a filver chalice, pa-
tine and fpoon, of 3 2 ounces and a half: a commu¬
nion table cloth of gold brocade St Giles s coat, wit 1
a little piece of red velvet which hung at his feet a
round filver euchari/l; two filyer cenfers of three
pounds fifteen ounces-, a filver (hip for mcenfe 3 a large
filver crofs, with its bafe, weighing fixteen pounds thir¬
teen ounces and a half 3 a triangular filver lamp 3 two
filver candlefticks, of feven pounds three ounces 3 other
two, of eight pounds thirteen ounces 3 a filver chalice
gilt, of 201 ounces 3 a filver chalice and crofs, of 75
ounces-, befides the priefts robes, and other veftments,
of gold brocade, crimfon velvet embroidered with gold
and green damafle.—Thefe were all fold, and part of
the money applied to the repairs of the church , the
reft was added to the funds of the corporation.
In the fteeple of St Giles’s church are three large
bells brought from Holland m 1621 3 the biggelt
weighing 2000lb. the fecond 700, and the third 500-
There are alfo a fet of mulic bells, which play every
day between one and two o’clock, or at any time in the
cafe of rejoicings. The cathedral is divided by paiti-
tion wafts 3 and the principal apartments are uftd a>
four feparate churches, which are dittmguilhed by the
names of the New or High Church, the Old Church, the
Tolbooth Church, which is contiguous to the pnlon, and
the Little Church, or lladdow's Hole Church, which
derives its latter name from a gentleman who had been.-
confined in it. The principal divifion is called tue
High Church, which has been elegantly repaired and
new feated. There is a very elegant and finely orna¬
mented feat for his majerty, with a canopy fupported
by four Corinthian pillars decorated in high tafte. i his
feat is ufed by the king’s commiflioner _ during the
time the General Affembly fits. On the right hand is
a feat for the lord high conftable of Scotland, whole
office it is to keep the peace within doors m his ma-
ieily’s prefence 3 it being the duty of the earl marlhal
to do the fame without. The feats belonging to the
lords of council and feflion are on the right of the lord
high conftable 3 and on the left of the throne was a feat
for the lord high chancellor of Scotland 3 but that office
being now aboliffied, the feat is occupied by others.
On the left of this fit the barons of exchequer 3 and,
to the left of them, the lord provoft, magistrates.
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t0™ councl1- The pulpit, king’s feat, and gal-
fiTkCfringes.C0Verel1 W‘'11 Cnmr°n V'lvCt Sold “nd
1 he aide of St Giles’s church is fitted up with feats
for the general aflembly who meet here; and there
is a throne for hts majefty’s commiffioner with a cano-
py of crimfon filk damalk, having the king’s arms era-
rendered with gold, prefented by the late" Lord Cath-
cart to his fucceffor in office. In this church is a mo-
nf "iv?1 dudnCated t0,;hIe memory °f Lord Napier, baron
Merchffion, well known as the inventor of lo^a-
rithms j a fecond to the earl of Murray, regent of
Scotland during the minority of James VI. j and a
third to the great marquis of Montrofe.
A- The Parliament Houfe, in the great hall of which
the ScQttiffi parliament ufed to affemble, is a magnificent
afi rfhC ^r11S,1 23 feet lonS and 42 broad, with
a fine arched roof of oak, painted and gilded. In this the
lawyers and agents now attend the courts, and Angle
judges fit to determine caufes in the firft inftance, or to
prepare them for the wffiole court, who fit in an inner
room formerly appropriated to the privy council. This
inner apartment has been lately repaired and very com-
modioufiy fitted up. In a niche of the wall is placed a
fine marble fiatue of Prefident Forbes, erefted at the
expence of the faculty of advocates. There are alfo
full-length portraits of King William III. Queen Mary
his confort, and Queen Anne, all done by Sir Godfrey
At!? of George I. John duke of Argyll and
Archibald duke of Argyll, by Mr Aikman of Caimey.
Above flairs were formerly the court of exchequer
and treafury chamber, with the different offices belong¬
ing to that department j but thefe were removed in
1^03 to the apartments in the royal exchange occu-
pie by the cuftomhoufe 5 and below is one of the moft
valuable hbranes in Great Britain, belonging to the
faculty of advocates. Befides 30,000 printed volumes,
there are many fcarce and valuable manuferipts, me¬
dals and coins .- here is alfo an entire mummy in its ori¬
ginal cheft prefented to the faculty (at the expence
of 300I.) by the earl of Morton, late prefident to
the Royal Society. As thefe rooms are immediately
emw the hall where the parliament fat, they are fub-
qect to a fearch by the lord high conftable of Scot-
land ever fmee the gunpowder plot 5 and this is fpeci-
fied in the gift from the city to the faculty. This li¬
brary was founded, in the year 1682, by Sir George
Mackenzie lord advocate. Among other privileges, it
is entitled to a copy of every book entered in Stationers
all Before the great door is a noble equeftrian ftatue
of Charles II. the proportions of which are reckoned ex¬
ceedingly juft. Over the entrance are the arms of Scot¬
land, with Mercy and Truth on each fide for fun-
porters. T
1 he court of leffion, the fupreme tribunal in Scot-
lanc confifts of 15 judges, who fit on a circular bench,
•clothed in purple robes turned up with crimfon velvet!
Six of thefe are lords of the jufticiary, and go the cir¬
cuit twice a-year ; hut, in that capacity, they wear
Icarlet robes turned up with white fatin.
5. The Tolbooth was erefted in 1561, not for the
purpofes merely of a prifon, but likewife for the ac¬
commodation of the parliament and other courts • but
it has fince become fo very unfit for any of thefe
-purpofes, that it is now' propofed to pull it down, and
/
C 526 ]
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rebuild it in Come other place, efpecially as It Is very Ed
nconvement in its prefent fituation on account of its
encumbering the ftreet. The provoft is captain of the
tolbooth, with a gaoler under him : and the latter has
a monopoly of all the provifions for the prifoners : a
ciicumftance which muft certainly be confidered as a
grievous oppreffion, thofe who are leaft able to pur-
chafe them being thus obliged to do fo at the higheft
price. Ihere is a chaplain who has a falary of 30I. a-
the^Nb ^Lon-hill, to be feen from
buil^ k !; B7dpl- 18 a COrre6Hon-houle or Bridewell,
built within thefe few years. It is a ftrong ftone fabric
Ser Dnwi,t T r 16 ¥ldin8 is in 'he {°™ of ,be
letter I), with a houfe for the governor at feme diftance
oppofite to the northern or rehtilineal part of it. The
whole is (unrounded by lofty walls, betwixt which and
the^ houfe is an area laid out as a garden.
of tbi t? !? •railt0 b-e °neTof the moft c°mplete buildings
of the kind m Britain. It confifts of five ftories • the
uppermoft of which is ufed as an hofpital for fick pri¬
foners and for ftore-rooms, &c. The other four ftories
are laid out m the following manner: A paffage goes
along the middle of the femicircular part of the build-
onMTn TTrT ?\eaCh hand‘ The aPartments
the outward fide of the curvature are fmaller than
thofe on the inner fide. They are double the number,
and are ufed as feparate bed-chambers for each of the
perions confined. The apartments on the inner fide of
e emicircle, of which there are thirteen in each
foiy, are allotted for labour. They have a grate in
W, ?„d look into the inner court. Oppffite £
them, m the flat fide of the building, is a dark apart-
ment with narrow windows, from which, without be¬
ing leen, the governor can fee how the prifoners in the
apartments for. work are employed. The court, or
pace m the middle between the flat and femicircular
part of the building, is roofed in at the top ; and a
great part of it is covered with glafs, fo as to light the
^hole. On the floor of the area is a ftove,^ vhich
unng winter heats the wffiole apartments allotted to
a our. 1 here is alfo a pulpit, from which a chaplain
preaches on Sundays j and the prifoners come into the
tront apartments to attend the fervice.
I he bed-chambers, looking outwardsto the country
are lighted by a long narrow window in each. The
window is glazed. The frame in which the glafs is
hxed is of iron. It turns on pivots fixed at the top
and bottom, fo as to be opened and ftmt at pleafure.
±.ach bed-chamber, which is about eight feet long bv
leven broad, is furniffied with a bed and a bible. The
frame of the bed is of iron, the bed confifts of a flraw
mattrefs of the beft quality. The whole floors and par¬
titions of the building are of ftone. No wood is ufed
excepting for the doors of the apartments. There are
cells, however, for folitary confinement for male cri-
mmals, m which the frames of the beds are of w-ood
e , by breaking them, tools or weapons of a danger¬
ous nature ffiould be obtained. Large cifterns, fupplied
with water from the city’s refervoir, are placed at the
top of the houfe, from which the water is diftributed to
the different ftories, and to a kitchen, walhing houfe
and baths, on the ground floor.
. I he inftitution is managed with great care. Befides
being fupermtended by the magiftrates of Edinburgh,
the
Beauties of
Scotland,
vol. 1.
p.n4.
EDI . [ 5
'Edinburgh, the fheriff of the county once each month vifits every
1 corner of it. It is kept in a flats of the moft perfed
cleannefs. The prifoners,_ when firft received are
clothed in a uniform belonging to the place } and t leir
own clothes, after being cleaned, arepreferved for them
till their difmiffion. They remain during, the day in
the apartments allotted to labour, from which they are
always difmiffed as foon as it becomes dark to their bed¬
chambers. The women fpin, and the men pick oakum.
Their food confifts of oatmeal porridge with imall beer
for breakfaft and fupper ; and for dinner, of broth
made of fat and vegetables, refembling what in Scotland
is called Jhcarer's kail (reaper’s broth). Ihofe that
exert any tolerable induftry are allowed bread to their
broth, and alfo a larger portion of porridge. Only
one death has occurred in the houfe. during the laft
four years j and in that cafe the individual who d.ed
had come into Bridewell under a complication of dil-
eafes. In truth, the food, clothing, good air, and
comfortable lodging, which are enjoyed in this place,
are far fuperior to what the greater number of inha¬
bitants can expeft to obtain on their return to the
world at large. To refide here, therefore, is a punifli-
ment from moral and not from phyfical caufes} that is
to fay, becaufe it is attended with the lofs of freedom
and of fociety, and becaufe it is a place of infamy.
y. There is a hall in the Writers Court belonging
to the clerks to his majefty’s flgnet, where there is alfo
an office for the bulinefs of the fignet. The office of
keeper of the fignet is very lucrative, and he is allowed
a depute and clerks under him. Before any one enters
into this fociety he muft attend the college for tw o
years, and ferve five years as an apprentice to one of
the fociety. There is a very excellent library belong¬
ing to this hall, which is rapidly increafing, as every
one who enters muft pay lol. towards it. He pays al¬
fo tool, of apprentice fee, and look wffien he enters.
8. The Exchange is a large and elegant building,
with a court of about C)0 feet fquare in the middle.
On the north fide are piazzas where people can walk
under cover, the other three fides being laid out in
{hops •, but the merchants have never made ufe of it to
meet in, ftill Handing in the ftreet as formerly. The
back part of the building formerly ufed for the general
cuftomhoufe of Scotland, w7here the commiffioners met
to tranfatl bufinefs, is now occupied by the offices con-
ne&ed with the Exchequer. They had above 20 offices
for the different departments, to which the accefs is by
a hanging flair 6o feet in height. In looking over the
window before he afeends this flair, a ftranger is fur-
prifed to find himfelf already .40 feet from the ground,
which is owing to the declivity on which the Ex¬
change is built. The fine manfion of Bellevue north
of the New Town is nowT converted into apartments for
the cuftomhoufe.
The Truftees Office for the improvement of fiffieries
and manufactures in Scotland is in the fouth-weft cor¬
ner of the Exchange j the fund under their manage¬
ment being part of the equivalent money given to Scot¬
land at the Union. This is diftributed in premiums
amongft thofe who appear to have made any confider-
able improvement in the arts.
9. The North Bridge, which forms the main paffage
of communication betwixt the Old and New Towns,
was founded, as has already been obfexved, in 1763 by
27 ] EDI . . . . „
Provoft Drummond 5 but the contract for. building it Edinbnrgri,
was not figned till Auguft 21. 17^5' archite£t
was Mr William Mylne, who agreed with the town
council of Edinburgh to finiffi the work for 10,1401.
and to uphold it for 10 years. It was alfo to be finifli-
ed before Martinmas 1769 : but on the 3d of Auguft
that year, when the work was nearly completed, the
vaults and fide walls on the fouth fell down, and five
people wrere buried in the ruins. I his misfortune wras
occafioned by the foundation having been laid, not up¬
on the folid earth, but upon the rubbifti of the houies
which had long before been built on the north fide of
the High ftreet, and which had been thrown out into
the hollow to the northward. Of this rubbifti there
were no lefs than eight feet between the foundation of
the bridge and the folid earth. Befides this deficiency
in the foundation, an immenfe load of earth which had
been laid over the vaults and arches in order to raife
the bridge to a proper level, had no doubt contributed
to produce the cataftrophe above mentioned.—The
bridge was repaired, by pulling down fome parts of the
fide walls, and afterwards rebuilding them 5 ftrengthen-
ing them in others with chain bars 5 removing the-
quantity of earth laid upon the vaults, and fupplying
its place with hollow arches, &c. The whole was fup-
ported at the fouth end by very ftrong buttreffes and
counterforts on each fide} but on the north it has .only
a Angle fupport.—The wffiole lengtn of the bridge,
from the High ftreet in the Old Town to Prince’s ftreet
in the New, is 11 25 feet •, the total length of the piers
and arches is 310 feet. The width of the three great
arches is 72 feet each j of the piers, 13-J feet, and of
the fmall arches, each 20 feet. The height of the great
arches, from the top of the parapet to the bafe, is 68
feet j the breadth of the bridge within the wall over
the arches is 40 feet, and the breadth at each end 50
feet.—On the fouthem extremity of this bridge ftands
the General Poll Office for Scotland; a neat plain build¬
ing, with a proper number of apartments for the bufi¬
nefs, and a houfe for the fecretary.
The communication betwixt the two towns by means
of this bridge, though very complete and convenient
for fuch as lived in certain parts of either, was jet
found infufficient for thofe who inhabit the weftern
diftridls. Another bridge being therefore neceffary,.
it was propofed to fill up the valley occafionally with
the rubbilh dug out in making the foundations of
houfes in the New Town ; and fo great was the quan¬
tity, that this was accomplifhed fo as to be fit for the
paffage of carriages in little more than four years and
a half.
10. The South Bridge is directly oppofite to the other,
lb as to make but one ftreet, croffing that called the
High Street almoft at right angles. It confifts of 19
arches of different fizes : but only one of them is vi-
fible, viz. the large one over the Cowgate j and even
this is fmall in comparifon with thofe of the North
Bridge, being no more than 30 feet wide and 31 feet
high! On the fouth it terminates at the Gniverfity
on one hand, and the Royal Infirmary on the other.
The Tron Church, properly called Thrift Church, ftands
at the northern extremity, facing the High ilreet, and
in the middle of what is now called. Haw/erV Square,
in memory of the worthy chief magiilrate Mto plan¬
ned thofe improvements, but did not live to fee them
executed>
EDI [
^Edinburgh..-executed. On the weft fide of this fquare the Mer-
' v" chant Company have built a very hartdfome hall for
the occafional meetings of their members. This bridge
was erefted with a defign to give an eafy accels to the
great number of ftreets and fquares on the fouth fide,
as well as to the country on that quarter from whence
the city is fupplied with coals. The ftreet on the top
is fuppofed to be as regular as any in Europe; every
lloufe being of the fame dimenfions, excepting that
between every two of the ordinary conftru&ion there
is one with a pediment on the top, in order to prevent
that famenefs of appearance which would otherwife
take place. So great was the rage for purchafing
ground on each fide of this bridge for building, that
the areas fold by public auction at 50I. per foot in
front. By this the community will undoubtedly be
confiderable gainers j and the proprietors hope to
indemnify themfelves for their extraordinary expence
by the vaft fale of goods fuppofed to attend the ftiops
in that part of the town 5 though this feems fomewhat
more dubious than the former.
11. The Concert Ha//, called alfo St Cecilia'1 s Hal!,
ftands in Niddery’s ftreet; and was built in 1762,
after the model of the great opera theatre in Parma.
The plan was drawn by Sir Robert Mylne, architeft
of Blackfriars bridge. The mufical room is of an oval
form, the ceiling being a concave elliptical dome, light¬
ed from the top by a lanthorn. The feats are ranged in
the fonn of an amphitheatre ; and are capable of con¬
taining 500 perfons, befides leaving a large area in the
middle of the room. The orcheftra is. at the upper end,
and is terminated by an elegant organ.
The mufical fociety was firft inftituted in the year
1728. Before that time, feveral gentlemen had formed
a weekly club at a tavern kept by one Steil, a great
lover of mufic, and a good finger of Scots fongs. Here
the common entertainment confifted in playing on the
harpfichord and violin the concertos and fonatas of
Handel, juft then publiflied. The meeting, however,
foon becoming numerous, they inftituted, in the year
above mentioned, a fociety of 70 members, for the
purpofe of holding a weekly concert. The affairs of
the fociety were regulated by a governor, deputy-go-
vemor, treafurer, and five direftors, who were annual¬
ly chofen by the members. The meetings were
continued ever fince that time on much the fame
footing as at firft, and the number of members in-
creafed to 200. The weekly concerts were on Friday ;
the tickets being given gratis by the direftors, and at-
.tention paid in the firft place to ftrangers. Oratorios
were occafionally performed throughout the year ; and
.the principal performers had alfo benefit concerts.
The band were excellent in their feveral departments;
and feveral of the members being alfo good performers,
took their part in the orcheftra. There were al¬
ways many applications on the occafion of a vacancy ;
and fuch wTas generally the number of candidates, that
it was no eafy matter to be admitted. This fociety,
however, has been long negle&ed, and the hall difpofed
of for other purpofes.
12. The Univerjity. In the year 1581, a grant was
obtained from King James VI. for founding a college
P_r _ univerfity within the city of Edinburgh ; and the
-citizens, aided by various donations from w7ell-difpofed
.perfons, purchafed a fituation for the intended new
528 ] EDI
college, confifting of part of the areas, chambers, and Edinburgh*
church of the collegiate provoftry and prebends of the V—1 J
Kirk-a-field, otherwife called Tetnplum et PrcefeBura
Sanclcv Maricc in ccttnpis, lying on the fouth fide of the
city. Next year, a charter of confirmation and erec-
tion wras obtained allb from King James VI. from
which the college to be built did afterwards derive all
the privileges of an univerfity.
I5^3» t^e provoft, magi-ftrates, and council, the
patrons'? ot this new inftitution, prepared the place
in the beft manner they could for the reception of
teachers and ftudents ; and in the month of October
the fame year, Robert Rollock, wdiom they had in¬
vited from a profefforftup in St Salvator’s College in
the univerfity of St Andrew’s, began to teach in the
new college of Edinburgh. Other profeflors wTere
foon after elefted ; and in the year 1586, Rollock w^aS
appointed principal of the college, and the following
year alfo profeffor of divinity, immediately after he
had conferred the degree of M. A. on the ftudents
w’ho had been under his tuition for four years. The
olhces of principal and profeffor of divinity remained
united till the year 1620.
In the 1617, King James VI. having vifited Scot¬
land after his acceffion to the crown of England, com¬
manded the principal and regents of the college of
Edinburgh to attend him in Stirling caftle; and after
they had there held a folemn philofophical deputation
in the royal prefence, his majefty wras fo much fatif-
fied with their appearance, that he defired their col¬
lege for the future might be called The College of King
James, which name it Hill bears in all its diplomas or
public deeds.
For feveral years the college confifted only of a
principal, who was alfo profeffor of divinity, with four
regents or profeffors of philofophy. Each of thefe
regents inftrudled one clafs of ftudents for four years,
in Latin, Greek, fchool logic, mathematics, ethics,
and phyfics, and graduated them at the conclulion of
the fourth courfe. A profeffor of humanity or Latin
was afterwards appointed, who prepared the ftudents •
for entering under the tuition of the regents; alfo a
profeffor of mathematics, and a profeffor of Hebrew
or Oriental languages. It was not till about the year
1710 that the four regents began to be confined each
to a particular profeflion; fince which time they have
been commonly ftyled Profejfors of Greek, Logic, Mo¬
ral Philofophy, and Natural Philofophy.—The firft me¬
dical profeffors inftituted at Edinburgh, wrere Sir Ro.
bert Sibbald and Doftor Archibald Pitcairn, in the
year 1-685 *. Thefe, however, were only titular pro-.
fefibrs ; and for 30 years afterwards, a fummer lebture *^p,Cf/e^e
on the officinal plants, and the diffe&ion of a human.^,,
body once in two or three years, completed the whole
courfe of medical education at Edinburgh. In 1720,
an attempt was made to teach the different branches
of phylic regularly; wffiich fucceeded fo well, that
ever fince, the reputation of the univerfity as a fchool
for medicine hath been conftantly increafing, both in
the illand of Britain, and even among diftant nations.
The college is endowed with a very fine library,
founded in 1580 by Mr Clement Little advocate,
who bequeathed it to the town council. They order¬
ed a houfe to be built for it in the neighbourhood of
St Giles’s church, where it was for feme time kept
under
E D I
EDI [529
KlmW-und« the care of the elded mtnifter of Edinburgh,
 tf—— but was afterwards removed to the college. I his co ~
ledlion is enriched, as well as others of a fimilar kind,
by receiving a copy of every book entered m Station¬
ers hall, according to the ftatute for the encourage¬
ment of authors. Befides this, the only fund it has
is the money paid by all the Undents at the uyuveiiity,
except thofe of divinity, upon their being matriculated 5
and a fum of 5I. given by each profeflbr at his admif-
fion. The amount of thefe fums is uncertain, but has
been eftimated at about 150I. annually. The ftudents
of divinity, who pay nothing to this library, have one
belonging to their own particular department.
Here are Ihown two ikulls, one almoft as thin as pa¬
per, pretended to be that of the celebrated George
Buchanan 5 and, by way of contrail, another faid to have
been that of an idiot, and which is exceilively thick.
Here alfo are preferved the original proteil againft t.ie
council of Conftance for burning John Hufs and Jerome
of Prague in 1417-, the original contracl of Queen
Mary with the dauphin of France, and fome valuable
coins and medals. There are alio feveral portraits j
particularly of Robert Pollock the firft principal of the
univerfity, King James VI. John Napier the inventor
of logarithms, John Knox, Principal Carftairs, Mr
Thomfon the author of the Seafons, &c. The mufeum
contains a good colledfion of natural curiolities, t le
number of which is daily increaling. The anatomical
preparations are worth notice, as are alfo thofe belong¬
ing to the profeffor of midwifery.
The celebrity of this college has been greatly owing
to the uniform attention of the magiftracy in filling up
the vacant chairs with men of known abilities in their
refpedtive departments.
The univerfity of Edinburgh “having been inftituted
after the Reformation, among a frugal people that had
no love for eccleliaftical dignities, it difters greatly
from the wealthy foundations which receive the name
of univerjities and colleges in England, or in the ca¬
tholic countries of the continent of Europe. I he uni¬
verfity of Edinburgh confifts of a fingle college, which
enjoys the privilege of conferring degrees. It confifts
of a principal, with a falary of 11 il. 2s. ojd. whofe of¬
fice is in a great meafure nominal, and of a profeffor in
each of the following departments :
Salaries. Edinbcrgfi,
Faculty of Theology,
Divinity
Church Hiftory
Oriental Languages
Salaries.
L, 161 2
100 o
119
12
o
8
Faculty of Law.
Law of Nature and Nations.—Salary
variable, but always above
Civil Law - * '
Scots Law
Civil Hiftory and Antiquities
Faculty of Medicine.
Anatomy and Surgery
Practice of Medicine
Botany
Materia Medica
Vol. VII. Part II.
300
100
100
100
50 o o
77
102
70
5-2
52
52
II3
100
52
5°
4
o
4
10
4
6
o
4
b
5t
o
5t
o
5t
8
o
-5t
o
1
Chemiftry
Theory of Medicine
Midwifery
Natural Hiftory
Faculty of Arts.
Moral Philofophy
Rhetoric and Belles Lettres J
Greek - - "
Latin -
Natural Philofophy . -
Mathematics
Practical Aftronomy
Logic -
Agriculture ^ *
« Of thefe, the profeffors of church hiftory and natu¬
ral hiftory, aftronomy, law of nature and nations, and
rhetoric, are in the gift of the crown. The profeffor
of agriculture was nominated by Sir William Pultney,
founder of the inftitution. The remaining chairs are
in the gift of the town-council of Edinburgh. Befides
thefe claffes here enumerated, the medical profeffors Beauties if
ternately give clinical lectures upon the cafes of the pa- scotianiji^ -I.
tients in the royal infirmary of Edinburgh.” 45.
The univerfity is now attended by not lefs than from
1200 to 1400 ftudents in the different departments of
fcience and literature.
The old buildings being very mean, and unfit for
the reception of fo many profeffors and ftudents, and
quite unfukable to the dignity of fuch a flourilhing
univerfity, as well as mconfiftent with the improved
ftate of the city, the Lord Provoft, Magiftrates, and
Council, fet on foot a fubfeription for erefting a new
ftrudlure, according to a defign of Robert Adam, Efq.
architect. Part of the old fabric has in tonfequence
been pulled down, and the new building is already in
confiderable forwardnefs. The foundation ftone was
laid on Monday the 16th of November, with great So¬
lemnity, by the Right Hon. Francis Lord Napier,
grand mafter mafon of Scotland, in the prefence of
the Right Hon. the Lord Provort, Magiftrates, and
Town Council of the city of Edinburgh, _ with the
principal, profeffors, and ftudents. of the univerfity of
Edinburgh, a number of nobility and gentry, and
the mailers, Officers, and brethren of all the lodges
of free mafons in the city and neighbourhood, who
marched in proceffion from the Parliament Houfe
down the High ftreet. After the different mafonic
ceremonials were performed, two cryftal bottles, caft
on purpofe at the glafs houfe of Leith, were depoiited
in the" foundation ftone. In one of thefe were put
different coins of the prefent reign, each of them be¬
ing previoufly enveloped in cryftal, in fuch an ingeni¬
ous manner, that the legend on the coins could be di-
ftin&ly read without breaking the cryftal. In the other
bottle were depofited Seven rolls of vellum, containing
a fhort account of the original foundation and prefent
ftate of the univerfity, together with feveral other pa¬
pers, in particular the different newfpapers, containing
advertifements relative to the college, &c. and a lift of
the names of the principal and profeffors, alfo of the
prefent lord provoft and magiftrates, and officers of
3 X the
E D I
[ 5
.Edinburgh tlie grand lodge of Scotland. The bottles being care'
’ fully fealed up, were covered with a plate of copper
wrapt in block tin ; and upon the under hde of the
copper were engraved the arms of the city of Edin¬
burgh jmd the univerfity; like wife the arms of tlie
Right Hon. Lord Napier, grand mailer mafon of Scot¬
land. Upon the upper fide, a Latin inicription, of
whigh the following is a copy :
ANNUENTE t)EO OPT. MAX.
REGNANTE GEORGlO III. PRINCIPE
MUNIFICENTPSSIMO J
academia: edinburgensis
iEDIBUS,
INITIO QJjTDEM humileimis,
ET JAM, POST DUO SECULA, PENE RUINOSIS J
NOVI IRTjuS jEDIFICII,
UBI COMMODITATI SIMUD ET ELEGANTIjE,
TANTO DOCTRINARUM DOMICIDIO
DIGNJF.,
CONSUIiERETUK,
PRIMUM LAPIDEM POSU1T,
PLAUDENTE INGENTI OMNIUM ORDINUM
FREQUENT! A,
VIR NOBIEISSIMUS
FRANCISCUS DO MINUS NAPIER,
REIPUB. ARCHITECTONIC A: APUD SCOTOS
CURIO MAXIMUS r
XVI. KAL. DECEAIB.
ANNO SALUTIS HUMANA: MDCCLXXXIX.
tera: architectontca: id3Iocclxxxix.
CONSOLE THOM A ELDER,
academia: pra:fecto gulielmo
ROBERTSON,
ARCHITECTO ROBERTO ADAM.
Q_. F. ¥. Q. S.
The call and well fronts of this pile are to extend 255
feet, and the fouth and north 358. There are to be
houfes ior the principal and fix or feven of the profelfors.
The library is to be a room of 160 feet in length ; the
mufeum for natural curiofities is to be of the fame
extent j and the dimenfions of the hall for degrees and
public exercifes are about 90 feet by 30. There are
likewife to be an elegant and moll convenient anato-
* Tits Is mical theatrea chemical laboratory; and large rooms
r-o-w jni/b- for inftruments and experiments for the profeflbrs of
mathematics, natural philofophy, and agriculture. The
whole, when finilhed, if not the moll fplendid llrudlure
of the fort in Europe, will however be the completed:
and moll commodious. The progrefs of the building
has now (1804) Hopped. The front was completed by
the aid ot royal munificence; but after an expendi¬
ture of 50,000!. it is fuppofed that not more than one
third of the plan has been executed.
The botanical garden belonging to the univerfity is
fxtuated at the dillance of about a mile, on the road
between Edinburgh and Leith. It confills of about five
acres of groundand is fumilhed with a great variety
of plants, many of them brought from the moll dillant
quarters of the globe. The profefior’is 'bbtanill to the
king, and receives a falary of I lol. annually for the
fupport of the garden. A monument, to the memory
of the celebrated botanift Litinseus, was creeled here by
30 ] EDI
the late Dr Hope, who firlt planned the garden, and Edinburgh,
brought it to perfection. —-y-—
The univerfity of Edinburgh, like the others in this
kingdom, fends one member to the General Affembly
of the church of Scotland ; and the widows of the
profeffors have a right to the funds of thofe of mini-
flers, the profelfors being trullees on that fund along
with the prelhytery of Edinburgh.
“ In the year 1772, the Board of Trullees for the en¬
couragement of Manufactures, &c. in Scotland, ap¬
pointed Mr Alexander Runciman, painter, to teach 20
boys or girls drawing, allowing him a yearly falary of
1 20I. He was fucceeded in this office by Mr Allan, to
whom followed Mr Graham. This inilitution being
appropriated for the ufe of manufactures, is not proper¬
ly a fchool of painting. In this lalt art, however, very
eminent teachers are to be found in Edinburgh, but no
public eftablilhment exilts for its encouragement.
“ Near the Univerfity there is alfo a Riding School,
called the Royal Academy for teaching Ever a fee. Tlie
teacher of this academy receives a falary of 200I. a-
year from the crown, and is accommodated with a ai¬
ding fchool of 1 20 feet in length by 40 in breadth,
and llables to a conliderable extent.
“ In Edinburgh there is eltablilhed, in imitation of
that in London, a Royal Society, which has publilhed fome
volumes of tranfaClions. It contains a number of mem¬
bers of great refpeClability; but in Edinburgh men of
letters are apt to be extremely jealous and unfociable
with regard to each other. This illiberality of temper
prevents the Royal Society from being of much value.
Great numbers of the moll accomplilhed and active
men of letters are unconnected with it, while it con¬
tains others who have been introduced to it merely by
their rank in the world, or the circumltance of having
attained to diltinguilhed literary fituations by the pa¬
tronage of men in power, who of late years have, in
this country, difplayed little of that anxiety to diferi-
minate and bring into notice men of literary talents,
which once formed the moll honourable charaCteriitic oi^cau,iies, °/
the nobles and Itatefmen of Scotland.” ^9 * ^ >
13. The Royal Infirmary was firlt thought of by the'
College of Phyficians in 1725. A filhing company
happening to be diffolved at that time, the partners
contributed fome of their llock towards the eltablilh-
ment of the Infirmary. A fubfeription was alfo fet on
foot, and application made to the General Alfembly to
recommend the fame throughout their jurifdiCtion.
This was readily complied with, and the affembly pair¬
ed an aCt for that purpofe ; but very little regard was
paid to it by the clergy. Notwithllanding this, how¬
ever, 2000I. being procured, a fmall houfe was opened
for the reception of the lick poor in Augult 1729. In
1736, the contributors towards the Infirmary wrere
ereCled into a body corporate by royal llatute ; and
after this the contributions increafed very conliderably:
by which means the managers were enabled to enlarge
their fcheme from time-to time; and at lalt to under¬
take the prefent magnificent ItruCture, the foundation
of which was laid in 1738. During 25 years, when
this inilitution was in its infancy, Lord Hopetoun be
itoived upon it an annuity of 400I. In 1750, Doc¬
tor Archibald Ker bequeathed to this incorporation
200I. a-year in the ifland of Jamaica. In 1755, the
lords -
EDI t 53
Edinburgh, lords cf the treafury made a donation to it of 8000I.
 which had been appointed for the fupport of invalids.
In return for this, the managers of the Infirmary con-
ilantly keep 60 beds m readmefs for the reception o
fick foldiers. This year alfo fick ferVants began to be
admitted into the Infirmary, and a ward was fitted up
for their reception. • j u.. u «■„
This inftitution, however, was more indebted to
George Drummond, Efq. than to any Other perfon. He
was feven times chofen lord proved of Edinburgh; and
always direfted bis attention to the improvement of the
city, particularly to that ot the Royal Infirmary. . 00
fenfible were the managers of their obligations to mm,
that, in their hall, they erected a buft of him with this
infeription, “ George Drummond, to whom this coun¬
try is indebted for all the benefit which it derives from
the Royal Infirmary.”—In 1748, the dock cf tue In¬
firmary amounted to 5000I.; in x755» ^ 7°7^ • e
fides the edate left by Do&or Ker ; m 1764, to
23,426b; and in 1778, to 27,074b .
The Royal Infirmary is attended by two _ pnyucians
chofen by the managers, who vifit their patients daily
in prefence of the dudents. All the members of the
College of Surgeons were obliged to attend m rota¬
tion, according to feniority. If any ihrgeon declined
attendance, he was not allowed to appoint a depute; and
the patients were committed to tne care of one cf foui
affiftant furgeons, chofen annually by tire managers :
this rvas formerly the mode of attendance, but the ma¬
nagers have m confecuence of a deciiion of the high
court of judicature aflumed to themfelves the lole right
of eledling the furgeons.—From the year 1762 to 1769,
there were admitted 6261 patients; which number ad¬
ded to 109 who were in the hofpital at the commence¬
ment of the year 1762, made, in all, 6370. Oi thefe,
4395 "were cured; 358 died : the red were either re¬
lieved, difinified incurable, for irregularities, or by
their own delire, or remained in the hofpitab—from
1770 to 1775, the patients annually admitted into the
Infirmary were, at an average, 1567; of whom 63
died. In 1776, there were admitted 1668, of whom
q7 died; and in 1777, the number admitted was I593>
and of deaths 52. In the year 1786, there were ad¬
mitted 1822 patients : Of thefe 1354 were cured ;
166 relieved ; 84 died; the red were either relieved,
dimuffed incurable, for irregularities, or by their own
desfire.
The building confids of a body and two wings, each
of them three dories high, with an attic dory and gar¬
rets, and a very elegant front. The body is 210 feet
long, and 36 broad in the middle, but at the ends only
24 feet broad. There is a bud of King George II. in
a Roman drefs, above the great door. I be wings are
70 feet long, and 25 broad. In the centre is a large
daircafe, fo wide that fedan chairs may be carried
up. In the different wards, 228 patients may be ac¬
commodated, each in a difierent bed. I here are
cold and hot baths for the patients, and alfo for the
\ citizens ; and to thefe lad the patients are never ad¬
mitted.
Belides the apartments necoflary for the fick, there
are others for the officers and fervants belonging to the
houfe. There are likewife rooms for the managers, a
confulting room for the phyficians and furgeons,, a
waiting room for the dudents, and a theatre that will
1 ] EDI
hold upwards of 2CO people foi performing elmur-Ediobrngle
gical operations. There is a mditary ward, tupport-
ed by the intereft of the 8000I. already mentioned ;
and in confequence of which a fmall guard is a -■
ways kept at the Infirmary. The wards for lick
fervants are lupported by collections at the church
doors. Befides the furgical attendance already men¬
tioned, there are two phyficians belonging to the
houfe, who are ele&ed by the managers, and have a
falary : there is j likewife a houfe-furgeon and apothe¬
cary. Students who attend the Infirmary paid rormer-
ly 3I. 3s. which is increafed to 5b 5s* annually, which
brings in a confiderable revenue towards defraying the
expence of the hottfe. Two wards are let apart for the
patients whole cafes are iuppofed to be moft intereftmg;
and the medical profeffors in the univerfity give cli¬
nical leftures upon them by rotation.
jq.. T/ie Public Difpenfary was founded by Dr Dun¬
can in 1776, for the poor whofe dileaies are of fuch a
nature as to render their admiliion into tiie Infirmary
either unnecefiary or improper. Here the patients
receive advice gratis four days in the week ; a r^gifte-
is kept of the difeafes of each, and of the effeas pro¬
duced by the medicines employed. Ail patients not
improper for difpenfary treatment are admitted on the
recommendation of the elder or church warden of the
parish where they relide. The phyficians officiate and
give leaures gratis ; fo that the apothecary who lodges
in the houfe, and the medicines, are the only expences
attending this uleful inflitution, I he expence of the
whole is defrayed by public contributions, and from
a fmall annual fee paid by the Undents who attend
the leclures. It is under the direction of a prefident,
two vice-prefidents, and 20 directors, ele&ed annually
from among the contributors. One guinea entitles a
contributor to recommend patients and be a governor
for two years, and five guineas gives the fame privilege
for life. ’ Under the fame management, there is an infli¬
tution for the gratuitous inoculation for the cow pox.
i 5. The Hio-/i School. The earlieft inftitution of a
grammar fchool in Edinburgh feems to have been a-
bout the year 1519. The whole expence beftowed
upon the firft building of tuis kind amounted oruy to
about 40I. fteriing. Another building, which had
been ere&ed for the accommodation of tne fcnolars in
1 578, continued, notwithftanding the great increafe
of their number, to be ufed for that purpofe till 1777,
The foundation of the prefent new building was laid
on the 24th of June that year by Sir William Forbes,
Grand Mailer of the Free Mafons. The total length
of this building is 1 20 feet from faith to. north ; the
breadth in. the middle 36, at each end 38 feet. The
great hall where the boys meet for prayers, is 68 feet
by 30. At each end of the hall is a room of 3 2 feet
by 20, intended for libraries. The building is two
ft cries high, the one 18, the other 17, feet in height.
The expence of the whole was reckoned at 4000I.
There is a re&or and four mailers, who teach from
400 to 500 fcholars annually. The falaries are trifling,
and the fees depend upon the reputation they have ob¬
tained lor teaching ; and as this has been for lome years .
very confiderable, the re&or’s place is luppofed to be
worth not lefs than Per atuium, a mailer’s about
half that fan. There is a janitor, whofe place is.fup-
pofed to be worth about 70I. a-vear. His bufinefs is
X 2
to
»
ED1 [ 5
Edinburgh to take care of the bpys on the play ground j and there
is a woman w’ho lives on the fpot as under-janitor,
whofe place may be worth about 25I. annually. There
is a library, but not large, as each of the boys pays on¬
ly one (hilling annually to its fupport.
There are four eftablifhed Englilh fchools in Edin¬
burgh 5 the mailers, of which receive a fmall falary,
upon exprefs condition that they (hall not take above
a limited fum per quarter from any of their fcholars.
There are likewife many other private fchools in Edin¬
burgh for all languages ; and, in general, every kind
ot education is to be had here in great perfedfion and
at a very cheap rate.
_ I6* The Mint is kept up by the articles of Union,
with all the offices belonging to it, though no money
is ever llruck here. It Hands in the Cowgate, a little
to the weft of the Engliffi church ; but is in a ruinous
Hate, though Hill inhabited by the different officers,
who have free houfes : and the bellman enjoys his fa¬
lary ky regularly ringing the bell. This place, as well
as the abbey of Holyroodhoufe, is an afylum for
debtors.
17. The Enghfh Chapel Hands near the Cowgate
Port, and was founded on the 3d of April 1771. The
foundation ftone wTas laid by General Oughton, with
the following infcription : Edificiifacr. Ecclejice epifc. An-
ghce, primum pofuit lapidem J. Adolphus Oughton, in
architeEioniccv Scotice r'epub. curio maximus, militum prce-
feclus, regnante Georgia III. tertio Ap. die, A. D.
MDCCLXXI. It is a plain handfome building, neatly
fitted up in the infide, and fomewhat refembling the
church of St Martin’s in the Fields, London. It is
9a feet long, 75 broad, and ornamented writh an ele¬
gant fpire of confiderable height. It is alfo furniihed
with an excellent bell, formerly belonging to the chapel
royal at Holyroodhoufe, which is permitted to be rung
for affembling. the congregation 5 an indulgence not
granted to the Prefbyterians in England. The expence
of tile building was defrayed by voluntary fubfcription j
and to the honour of the country, people of all per-
fuafions contributed to this pious work. It has already
coft.yoool. and will require loool. more to finiffi the
portico. This church is built in a Angular manner,
viz. from fouth to north, and the altar-piece ftands
on the eaft lide. Three clergymen officiate here, of
whom the firft has 150I. the other two iool. each:
the altar-piece is finely decorated, and there is a good
organ.
There is another Epifcopal chapel, but fmall, in
Blackfriars wynd, which was founded by Baron Smith
in the year 1722. There are alfo fome meetings of
the Epifcopal church of Scotland, who adhere to their
old forms, having ftill their bilhops and inferior clergy,
tor fome time thefe wrere fubjecled to penal laws, as
they refufed to take the oath to government, or men¬
tion the prelent royal family in their public prayers:
] EDI
but having conformed, and taken the oatli of allegiance,Edinburgh,
their conducl has been approved of by his majefty ; fo
that now every denomination of Chriftians in Britain
pray for the royal family on the throne.
18. Henats Hofpital owes its foundation to George
Heriot, goldlmith to James VI. who acquired by his
bufinefs a large fortune. At his death, he left the
magiftrates of Edinburgh 23,625!. 10s. “ for the
maintenance, relief, and bringing up of fo many poor
and fatherlefs boys, freemen’s Ions of the town of
Edinburgh,” as the above fum Ihould be fufficient
for. I his hofpital is finely fituated on the weft
end of the fouth ridge, almoft oppolite to the caltle,
and is the moft magnificent building of the kind in
Edinburgh. It was founded in July 1628, according
to a plan (as is reported) of Inigo Jones j but the work
being interrupted by the civil wars, it was not finiih-
ed till the year 1650. The expence of the building
is faid to have been upwards of 30,000!. (a) : and
the hofpital is now polfeffed of an income of about
3000I. a-year j though this cannot be abfolutejy af-
certained, as the rents are paid in grain, and of courfe
muft be ffudfuating.
. It ftands on a riling ground to the fouth-weft of the
city, and is a fquare of 162 feet without, having a
court 94 feet fquare in the infide, with piazzas on
three of the fides. There is a fpire with a clock over
the gateway, and each comer of the building is orna¬
mented with turrets j but notwithstanding the magni¬
ficent appearance of the outfide, the inner part is
far from being convenient. There is a ftatue of the
founder over the gateway, in the drefs of the times,
and a very good painting of him in the governors
room, with a picture of the late treafurer Mr Carmi¬
chael. There is a chapel 61 feet long and 22 broad,
which is now repairing in fuch a manner as will make
it worthy of notice. When Cromwell took poffelfion
of Edinburgh after the battle of Dunbar, he quartered
bis fick and wounded foldiers in this hofpital. It was
applied to the fame purpofe till the year 1658, when
General Monk, at the requeft of the governors, re¬
moved the foldiers j and on the nth of April $659,
it was opened for the reception of boys, 30 of whom
were admitted into it. The Auguft after, they were
increafed to 40 j and in 1661, to 52. In 1753 the
number was railed to 130, and in 1763 to 140 j but
fince that time it has decreafed.—In this hofpitai the
boys are inftru&ed in reading, writing, arithmetic, and
a knowledge of the Latin tongue. With fuch as choofe
to follow any kind of trade, an apprentice fee of 30I.
is given when they leave the hofpital; and thofe who
choofe an academical education, have an annuity of
10I. a-year bellowed on them for four years. The
whole is under the overfight of the treafurer, who has
under him a houfe governor, houfekeeper, and fchool-
mafters.
19, IVatfords
(a) It is to be obferved, that money then bore 10I. per cent, intereft.—The above firms are taken from Mr
Amot’s Hiftory of Edinburgh, who fubjoins the following note. “ Where Maitland had eollefled his moft:
erroneous account of George Heriot’s effefls we do not know. He makes the fum received, out of HerioUs
effects, by the governors of the hofpital, to be 43,608!. us. 3d. being almoft double of what they really
got. I his blunder has been the caufe of many unjuft muxmurings againft the raagiftrates of Edinburgh, and
even the means of fpiriting up lawfuits againft them,”
,9' W4°f 4" t”St Wll^3
EW i, .6,6, .hen accountant a^nt T^ocl.t; “
of the bank of Scotland ; after that he became jeceiy r [ fs inconfiderable •, but the inftitution is
of the city’s import on ale, treasurer to the Merchants The revenue isj of charltabie perfons.
Maiden Hofpital, and to the fociety lor propaga mg PP h p -t j orphans are received from any part
Chriftian knowledge. Dying a bachelor in 1723, he Into this hoipital orphans ^
v^iirnuaii is.iiv;v>x^v*6x,. —o . r 1
left 1 2 oool. for the maintenance and education ot the
children and grandchildren of decayed members of
the merchant company of Edinburgh. Ihe icheme,
however, was not put in execution till the year 1730,
when the fum originally left had accumulated to
20,000!. The prefent building was then erected, m
which about 60 boys are maintained and educated.
It is much lefs magnificent then Heriot’s hofpital, but
the building is far from being defpicable. _ It Hands to
the fouthward of the city at a fmall diftance bom
Heriot’s hofpital, and was erefted at the expence ot
coool.: its prefent revenue is about 1700I. It is un¬
der the management of the mailer, artiftants, and trea¬
surer of the Merchant Company, four old bailies, the
old dean of guild, and the two mmifters oi the Old
church. The boys are genteelly clothed and liberally
educated. Such as choofe an university education are
allowed 10I. per annum for five years : thofe who goto
trades have 20I. allowed them for their apprentice tee,
and at the age of 25 years, if they have behaved proper¬
ly, and not contracted marriage without content ot the
governors, they receive a bounty of 50I. Ihe boys are
under the immediate infpeftion of the treafurer, fchool-
mafter, and houfekeeper.
20. The Merchants Maiden Hofpital was eftabhlhed
by voluntary contribution about the end of the laft cen¬
tury, for the maintenance of young girls, daughters ot
the merchants burgeffes of Edinburgh. The gover¬
nors were ereaed into a body corporate, by ad of par¬
liament, in 1707. The annual revenue amounts to
12 col. Seventy girls are maintained m it j who, up¬
on leaving the houfe, receive 3I. 6s. 8d. excepting
a few who are allowed 8k 6s. 8d. out of the funds o
the hofpital. The profits arifing from work done m
the houfe are alfo divided among the girls, according
to their induftry.
21. The Trades Maiden Hofpital was founded in the
year 1704 by the incorporations of Edinburgh, for the
maintenance of the daughters of decayed members, on
a plan fimilar to that of the merchants hofpital. 1 o
this, as well as to the former, _ one Mrs Mary Erikme,
a widow gentlewoman, contributed fo liberally, t .at
fhe was by the governors ftyled joint foundrys of t ic
hofpital. Fifty girls are maintained in the houfe, who
pay of entry money ll. 13s 4d. } and, when they
leave it, receive a bounty of 5I. us. I-M- d he re¬
venues are eftimated at 600k a-year.
22. The Orphan Hofpital was planned in 173.2, by
Andrew Gairdner merchant, and other inhabitants.
It was promoted by the fociety for propagating Chri¬
ftian knowledge, by other focieties, by voluntary iub-
fcriptions, and a colleftion at the church doors.—In
1730 the managers hired a houfe, took in 30 orphans,
maintained them, gave them mftrufhons m reading
and writing, and taught them the weaving bulmeis.
In 1735, they were erefted into a body corporate
by the town of Edinburgh : and, jn 1742, they ob¬
tained a charter of erection from his late majefty, ap-
of the kingdom. None are admitted under feven, nor
continued in it after 14 years of age. r ,
The orphan hofpital is fituated to. the eaft ok the
North bridge j and is a handfome building, confiftmg
of a body and two wings, with a neat Ipire, furmihed
with a clock and two bells. The late worthy Mr
Howard admits, that this inftitution is one of the mok
ufeful charities in Europe, and is a pattern lor all m-
ftitutions of the kind. The funds have been, confider-
ably increafed, and the building greatly improved
through the attention and exertions of Mr Ihomas iod
formerly treafurer. . . . ,
23. The Trinity Hofpital. This was originally found¬
ed and amply endowed by King James .II.’s queen. t
the Reformation, it was ftripped of its revenues j but
the regent afterwards bellowed them on the provoft ot
Edinburgh, who gave them to the citizens for the ule
of the poor. In 1585, the town council purchafed
from Robert Pont, , at that time provoft of 1 rimty col¬
lege, his intereft in thefe {objects j and the tranfachon
was afterwards ratified by James VI. -The 10 pita was
then repaired, and appointed for the reception oi poor
old burgeffes, their wives and unmarried children, not
under 30 years of age. In the year 1700, this hoi¬
pital maintained 54 perfons j but, fince that time,, the
number has decreafed.—The revenue confifts in a
real eftate of lands and houfes, the grofs rents of which
are 762k a year, and 5500k lent out fti bonds at 4 per
CeXhis hofpital is fituated at the foot of Leith wynd,
and maintains about 50 of both fexes, who are com¬
fortably lodged, each having a room for themielves.
They are fupplied with roaft or boiled meat every day
for dinner, have money allowed them for clothes, and
likewife a finall fum for pocket money. I here is
a final! library for their amufement, and they have a
chaplain to fay prayers. There are fome out-pen-
fioners who have 6k a-year, but thefe are difcouraged
by the governors. The funds are under the manage¬
ment of the towm council. .
24, The Charity IVorkhoufe was erefted m 1743. by
voluntary contribution. It is a large plain building,
on the fouth fide of the city. Here the poor are em¬
ployed, and are allowed twopence out of every Hulling
they earn. The expence of this inftitution is fuppo-
fed not to be lefs than 4000k. annually as about 700
perfons of both fexes, including children, are main¬
tained here, each of whom cannot be reckoned to coll
lefs than 4k ios. per annum j and there are befides
300 out-penfioners. . The only permanent fund for de¬
fraying this expence is a tax of two per. cent, on t ic
valued rents of the-city, which may bring in about
600k annually j ■ and thare are other funds which yield
about 400k The reft is derived from colleftions at
the church doors and voluntary contributions j but as
thefe always'fall Ihort of what is reqmfite, recourle mult
frequently be had to extraordinary colkaions. ihe
fum arifing from the rents of the city, however, is
0 conilantly,
E D I
Edinburgh. CQiifl.mtly increafaig • but the members of the college
of jullice arc exempted from the tax.
25. lo the fouth-welf of the caltle, near a fuburb
called the Wrights Houfes, on the f;te ol a very ancient
building, which was demolilhed to make way for it,
truiefhie's Hofpital has lately been creeled. Its appel¬
lation is derived from the founder, an eminent manu-
iaclurer of fnuft in Edinburgh. It is intended for the
lupport of aged perfons 5 and thole bearing the name
of the founder are preferred. It is a neat ilcne build-
ing, executed in a ftyle of moderate expence, with a
fmall tow’er in the centre and a parapet, and Gothic tur¬
rets at luitable difiance's around the roof.
u Belides thefe there are to be found in Edinburgh
feveral charitable eltabliihments, which, though not
furnilhed with coltly buildings, are not of a lefs bene¬
volent or valuable nature. Of thefe, one of the molt
diltinguilhed is the Hofpital or Workhoufe, or Afylum,
as it is called, for the Indujlrious Blind; which is fup-
ported by the contributions of charitable perfons, and
by the price of the articles manufactured in it. Here
the blind are taught Inch trades as may enable them to
earn a fubfiftence, or at lealt aid them in contributing
to their own fupport. They manufacture balkets,
matts, dec. •, and lome of them have been taught to
aCt as weavers^ for which purpole they ufe the fly-
fhuttle.
“ i he Magdalene Mfylum alfo deferves notice; in
wThich a molt laudable attempt has of late years been
made, by a benevolent fociety, to reclaim, from vice
■and mifery, wmmen who have degraded themielves by
public prollitution, but wrho think fit to retire thither
with the view of abandoning their mode of life, and of
fupporting themfelves by indultry. This inllitution is
managed with a’ degree of care and delicacy wdrich does
the higheft credit to its patrons. The objects of this
charity are kept concealed : they reap the fruits of
their own labour 5 and every effort is made to procure
employment for them. In particular, needle-work of
a ll forts is executed in it in the neateft manner j and
linen is walked, at moderate prices, for fuch perfons
in the city as think fit to tranfmit thefe articles to the
fociety.
11 Befides all thefe charities, there is an hofpital in
the city for Lying-in IVonien, under the care of the
profeilor of midwifery : which is an inllitution analagous
to that of the Royal Infirmary.—There is a Society for
the Belief of the Dflitute Sick, which has received con-
fiderable public countenance, though it has no appro¬
priate building or local ellablifhment.—An inllitution
of a peculiar nature, not unconnected with the prefent
lubjeft, called the Repoftory, ought not to pafs un¬
noticed. It is a Ihop or ware-room on South Bridge
Street, to which ladies in llraitened circumltances have
an opportunity of fending for fale curious, beautiful, or
ufeful articles of needle-work, with the price affixed.
When a purchafer has been found for the goods, the
proceeds are tranfmitted in fuch a manner as to prevent
its being known to the public by whom the articles
Beaut',es of were prepared. This inllitution has been promoted
Scotland, I. by the Duchefs of Buccleugh and many other perlons
6^- of rank.”
There are two other charity workhoufes in the fub-
urbs, much on the fame plan with that now deferibed ;
1 534 ]
E D I
one in the Canongate, and the other in Si Cuthbert’s Edinburgh*
or Well kirk parilh. 1 v~—*
f0 this account of the charitable ellablilhments in
Edinburgh, we lhall add that of fome others 3 which,
though not calculated to decorate the city by any
public building, are perhaps no lefs deferving of
prade than any we have mentioned. The firll is that
of Captain William Horn ; who left 3 5C0I. in trull to
the magiilrates, the annual profits to be divided on
Chrillmas day to poor out-day labourers, who mull at
that feafon of the year be dellitute of employment 3
five pounds to be given to thofe who have large fami¬
lies, and one half to thofe who have fmaller.
Another charity is that of Robert John lion, LL. D.
of London, who in 1640 left 3000I. to the poor of
this city 3 1000I. to be employed in fetting them to
work, another 1000I. to clothe the boys in Heriot’s
Hofpital, and the third 1000I. to burfars at the uni-
verfity.
About the beginning of this century John Strachan
left his eltate of Craigcrook, now upwards of 300!.
a-year, in trull to the prelbytery of Edinburgh, to be
by them dilpofed of in fmall annual fums to poor
old people not under 65 years of age, and to orphans
not above 12.
d here is befides a fociety for the fupport of the in-
duftrious poor, another for the indigent lick, and there
are alfo many charity fchools.
Having thus given an account of the moll remark¬
able edifices belonging to Old Edinburgh, we fiiali
now proceed to thofe of the New Town. This is
terminated on the call fide by the Calton hill, round
which there is a pleafant walk, and which affords
one of the finefl profpecls that can be imagined, vary¬
ing remarkably almofl at every flep. On this hill is
a burying ground, which contains a fine monument
to the memory of David Hume the hiilorian.—On
the top is an obfervatory, the fcheme for building
which was firll adopted in the year 1736 5 but the di-
ilurbance occaficned by the Porteous mob prevented
any thing from being done towards 'the execution of it
at that time, 'ihe earl of Morton afterwards gave
look for the purpofe of building an obfervatory, and
appointed Mr M‘Laurin profeffor of mathematics, to¬
gether with the principal and fome profeffors of the
univerfity, trultees for managing the fum. Mr M‘Lau-
rin added to the money above mentioned the profits
arifing from a courfe of ledlures which he read on ex¬
perimental philofophy 3 which, with fome other fmall
fums, amounted in all to 3001.3 but Mr M‘Laurin
lhe defign was dropped.—Afterwards the mo¬
ney was put into the hands of two perfons who became
bankrupt 3 but a confiderable dividend being obtained
out of their effedls, the principal and interell, about
the year 1776, amounted to 400I. A plan of the
building was made out by Mr Craig architect 3 and the
foundation Hone was laid by Mr Stodart, lord provoll
of Edinburgh, on the 25th of Augull 1776. About
this time, however, Mr Adam architect happening to
come to Edinburgh, conceived the idea of giving the
whole the appearance of a fortification, for which its
fituation on the top of the Calton hill was very much
adapted. Accordingly a line was marked out for en-
clofing the limits of the obfervatory with a wall con-
Itrufled
4
EDI [ 53
Edinburgh, ftrufted with buttreffes and embrafures, and having
1 V 1 Gothic towers at the angles. Thus the money dengned
for the work was totally exhaufted, and the obfervatory
itill remains unfinhhed j nor is there any appearance of
its being foon completed either by voluntary fublcnp-
tion or any other way. , , . .
26. Proceeding to the weftward, the nrft remarkable
building is the Theatre, which Hands oppofite to the
RegiHer Office, in the middle of Shakefpeare Square.
The building is plain on the outiide, but elegantly
fitted up within, and is generally open three days m
the week, and when full will draw about 150I. a-night}
fo that the manager generally finds himielf wrell re¬
warded when he can procure good actors.
Entertainments of the dramatic kind came very eariy
into faihion in this country. I hey were at hrit only
reprefentations of religious iubjeefs, and peculiarly Ue-
figned to advance the intereits of religion ^ the clergy
being the compofers, and Sunday the principal time or
exhibition. In the 16th century, the number ot play-
houles was fo great, that it was complained of as a
nuifance, not only in Edinburgh, but throughout the
kingdom. They foon degenerated from their original
inilitution } and the plays, inftead of being calculated
to infpire devotion, became filled with all manner ox
buffoonery and indecency.—After the Reformation,
'the Prelbyterian clergy complained of thefe indecencies;
N and being adfuated by a fpirit of violent zeal, anathe¬
matized every kind of theatrical reprefentation w thiL-
ever. Kiug James \ I. compelled them to pafs from^
their cenfures againft the ftage but in the time of
_ Charles I. when fanaticifm ivas carried to the utmoil
length at which perhaps it w7as poffible lor it to ariive,
it cannot be fuppoied that ftage plays tvould be tolera¬
ted.—It feems, however, that amufettients of this
kind were again introduced at Edinburgh about the
year 1684, when the duke of h ork kept his court
there. His refidence at Edinburgh drew off one half
of the London company, and plays were acted in E-
dinburgh for fome little time. The misfortunes at¬
tending the duke of York, however, and the eftablifh-
ment of the Prefbytcrian religion (the genius of which
is unfavourable to amufements of this kind), foon put
a flop to the progrefs of the ftage, and no theatrical
exhibition was heard of in Edinburgh till aiter the
year 1715. The firft adventurer w7as Signora Violante,
an Italian, remarkable for feats of ftrength, tumbling,
&c. In this way fixe firft exhibited in a houfe at the
foot of Carubber’s clofe, wdxich has fince been employ¬
ed by different feftaries for religious purpofes. Meet¬
ing witb good fuccefs, fixe foon invited a company of
comedians from London *, and thefe being alto well
received,. Edinburgh continued for fome years to be
entertained with tlxe performances of a ftrolling com¬
pany, who vifited it annually. Becoming at laft, how¬
ever obnoxious to the clergy, they were in 1727
prohibited by the magiftrates from afting within their
jurifdicfion. But this interdi61 was fufpended by the
court of feflion, and the players continued to perform
as ufual.
Still, however, theatrical entertainments wrere but
rare. The town wras vifited by itinerant companies
only once in two or three years. They performed in
the Taylor’s Hall in the Qwgate •, which, when the
hmife wras full, would have drawn (at the rate of 25. 6d.
s ] *EDI
for pit and boxes; and is. 6d. for the gallery) 40I. or
45!. a night. About this time an act of parliament
was paffed, prohibiting the exhibition of plays, except
in a houfe licenfed by the' king. Of this the preffiy-
tery of Edinburgh immediately laid hold •, and at their
own expence brought an atlion on the ftaLUxe agaiuft
the players. The caufe was by the court of let lion
decided againft the players j who thereupon applied to
parliament for a bill to enable bis majefty to Ucenle a
theatre in Edinburgh. Againft this bill petitions were
prefented in 1739 to the houfe of commons by the
magifti'ates and town council, the principal and pro-
feffors of the mxiverixty, and the dean of guild and his
council j in conlequence of which, the affair w as drop¬
ped. All this oppofition, however, contributed in
reality to the fuccefs of the players j for the ipirit of
party being excited, a wTay of evading the aft was ea-
£4y found°out, and the houfe was frequented more
than ufual, infomuch that Taylor’s Hall was found in-
fufficient to contain the number of fpectatois.
The comedians now fell out among themfelves, and
a new playhoufe was credited in the Canongate in the
year 1746. The confequence of this was, that the old
one in Taylor’s Hall became entirely deferted, and
through bad conduct the managers of the new theatie
foon found themfelves greatly involved. At laft, a riot
enfuing through diiTenlions among tne performers, the
playhoufe wTas totally demolifhed.—When the extenfion
of the royalty over the fpot where the New I on 11 is
built was obtained, a claufe was likewife added to^ the
bill, enabling his majefty to licenfe a theatre in Edin¬
burgh. This was obtained, and thus the . oppofition
of the clergy for ever filenced.. But notwithiLanding
this, the high price paid by the managers to the pa¬
tentee, being no lefs than 500 guineas annually, pre¬
vented them effeflually from decorating the hou.e as
they would otherwife have done, or even from always
retaining good aefors in their fervice 5 by wixich means
the fuccefs of the Edinburgh theatre has not been io-
great as might have been expefted.
Not far from this building, an amphitheatre v.as
opened in 179a, on the road to Leith, for equeftrian
exhibitions, pantomine entertainments, dancing, and
tumbling. The circus was 60 feet diameter •, and in the
forenoon ladies and gentlemen were taught to ride,.
The houfe held about 1500 people. This building
has been fince converted into an elegant ana commodious
concert room.
27, The Re^iJIer Office. This work was firft fug-
gefted by the late Earl of Morton, iord-regifter of Scot-
fand, with a view to prevent the danger which attended
the ufual method of keeping the public records. In
« former times, indeed, thefe fuffered from a variety of
accidents. Edward I. carried off or deftroyed moft .of
them, in order to prevent any marks of the former in¬
dependence of the nation from remaining to pofterity.
Afterwards Cromwell fpoiled this nation of its records,
moft of which were fent to the T ower of London. At
the time of the reftoration, many of them were fent
down again by fea } but one of the veflels was ftiip-
wrecked, and the records brought by the other have
ever ftnee been left in the greateft confufion.—I he
Earl of Morton taking this into connderation, obtain¬
ed from his majefty a grant of 1 2,oooh out ol the .for¬
feited eftates, for the purpofe of building a regifter
office,,
EDI [ 536
Tidinburgb. office, or houfe for keeping the records, and difpofmg
v'- 1 them in proper order. The foundation was laid on
the 27th of June 1774, by Lord Frederic Campbell
lord-regifter, Mr Montgomery of Stanhope lord advo¬
cate, and Mr Miller of Barlkimming lord juflice clerk j
three of the truftees appointed by his majelty for exe¬
cuting the work. The ceremony was performed under
a difcharge of artillery, in prefence of the judges of the
courts of feffion and exchequer, and in the fight of a
multitude of fpedlators. A brafs plate was put into the
foundation done with the following infcription : Con-
SERVANDIS TaBULIS PuBLICIS FOSITUM EST, ANNO
M.DCC.EXXIV, MUNIFICENTIA OFTIMI ET PIETISSIMI
FRiNCiPis Georgiii Tertii. In a glafs vafe herme¬
tically fealed, which is alfo placed in the foundation
done, are depofited fpecimens of the different coins of
his prefent majefty.
The front of the building direftly faces the bridge,
extends from eaft to weft 100 feet, and is 40 feet back
from the line of Prince’s ftreet. In the middle of the
front is a fmall projeefion of three windows in breadth.
HereMs a pediment, having in its centre the arms of
Great Britain, and the whole is fupported by four Co¬
rinthian pilafters. At each end is a tower projefting
beyond the reft of the building, having a Venetian
window in front, and a cupola on the top. The front is
ornamented from end to end with a beautiful Corin¬
thian entablature. In the centre of the building is a
dome of wooden work covered wdth lead. The inftde
forms a fa loon 50 feet diameter and 80 high, lighted
at top by a copper window 15 feet in diameter. Round
the whole is a hanging gallery of ftone, with an iron
balluftrade, which affords conveniency for preffes in
the walls for keeping the records. The whole number
of apartments is 97 j all of wdiich are vaulted beneath,
and warmed with fire-places. This building, wffiich is the
moft beautiful of Mr Adam’s defigns, has been execu¬
ted in a fubftantial manner, in about 16 years, at the
expence of near 40,000!. and is one of the principal
ornaments of the city. A ferjeant’s guard is placed
here from the caftle, for the further proteftion of the
records. It is intended to place a ftatue of his prefent
majefty in the front of the building, with the lion and
unicorn above the centinels boxes. The lord-regifter.
has the direction of the whole, and the principal clerks
of feffion are his deputes. Thefe have a great num¬
ber of clerks under them for carrying on the bufinefs
of the court of feffion. The lord-regifter is a mini-
fter of ftate in this country. He formerly collected
the votes of the parliament of Scotland, and ftill col-
lefts thofe of the peers at the eleftion of 16 to reprefent
them in parliament.
27. On the eaft fide of St Andrew’s fquare Hands
the General Excife Office, built by the late Sir Law¬
rence Dundas for his own refidence, but fold by his
fon for the above purpofe. It is a very handfome
building, with a pediment in front ornamented with
the king’s arms, and fupported by four Corinthian
pilafters •, and, in conjunction with the two comer
houfes, has a fine effect.
28. St Andrew's Church Hands on the north fide of
George’s ftreet, It is of an oval form j and has a
very neat fpire of 186 feet in height, wdth a chime of
eight bells, the firft and only one of the kind in Scot¬
land, It has alfo a handfome portico in front.
3
]
EDI
29. Oppofite to St Andrew’s church is the Edinburgh
fficians Hall, defigned for the meetings of the facul- ""“v
ty, and which has a portico refembling that of the
church.
30. Farther to the wTeftw7ard, on the fouth fide, ftand
the Affifembly Rooms, which though a heavy looking
building on the outfide, are neverthelefs extremely ele¬
gant and commodious within. The largeft is 100
feet long and 40 broad, being exceeded in its dimen-
fions by none in the illand, the large one at Bath ex¬
cepted. Weekly affemblies are held here for dancing
and card-playing, under the direction of a mafter of
ceremonies j admifiion tickets five {hillings each.
“ There are three Banking Companies in Edinburgh
eftabliflied by ftatute, or by royal charters. Thefe are,
the Bank of Scotland, commonly called the Old Bank,
the Royal Bank of Scotland, and the Britiih Linen
Company.
31. “ The Bank of Scotland, commonly called the Old
Bank, wras erefted by aft of parliament, A. D. 1695.
By the ftatute of ereftion, the company wras empowered
to raife a joint flock of 1,200,oool. Scots, or ioo,oool.
Sterling, for the purpofe of carrying on a public bank.
The fmalleft {hare which any perfon could hold in the
bank was declared to be 1000I. Scots j and the largeft
fum for which any one wras allowed to fubferibe wTas
20,oool. of the fame money. Eight thoufand are de¬
clared to be the qualification neceffary to entitle any one
to be elefted governor j 6000I. deputy governor j and
3000I. for each direftor. The management of the af¬
fairs of the company wTas veiled in a governor, deputy
governor, and twenty-four direftors j and in choofing
thele managers, each proprietor w7as declared to have a
vote for every 1 oool. of ftock held by him.
“ The office of this company has hitherto been held
in a houfe down a narrow lane at the fouth fide of that
part of the High ftreet called the Lawn-market j but,
at a great expence, they have erefted for their accom¬
modation a building wffiich will fpeedily be ready to be
occupied, and which is fituated to the northward of the
High ftreet, in full view of Prince’s ftreet. This is at
once a magnificent and beautiful fabric. The back of
the building is towards Prince’s ftreet j and here, while
erefting, it had the difad vantage, from its vaft height, of
having fomewffiat the afpeft of a tower. This effeft,
however, is now removed by reftoring the earth for the
purpofe of covering up the lower part of it, and by a wall
of confiderable height in the nature of a curtain, wffiich
has been added to augment its apparent breadth. It
forms, upon the wffiole, a beautiful and moft fuperb fa¬
bric. As a work of magnitude, it is feen to moft advan¬
tage from the mound of earth wffiich connefts the Old
, and the New Town, at that part of the mound wffiich is
in the direftion of the north-wTeft angle of the building.
Here the eye is filled by the full view of two fides of
the fabric, and by a difplay of its great height. The
refult of which is, that as a magnificent and ftupen-
dous ftrufture, it feems to have no rival in this coun¬
try.
“ This banking company has eftablifiied branches in
every confiderable town in Scotland, excepting Glafgow,
wffiich, in confequence of an amicable adjuftment to a-
void rivalfhip, is left to the Royal Bank. By agree¬
ment, the latter has a branch at Glafgow, and no branch
in any other town in Scotland.
Kctinbui-gti-
EDI [ 537 1 EDI
4 , “ The W Bank was eflablilhed in the follow- and Company ; and then notes W
By the articles of union, Scotland was de-
poflefTed a moft Edinburgh^
mg manner : t.*^ ““-v   . ' , . , i • j
dared to be liable to the fame duties which were levied
by way of cuftoms or excife in England. As thefe du¬
ties had, in the latter of thefe nations been appropria¬
ted for the difeharge of debts contraaed by England
before the union, it was found reasonable to give Scot¬
land an equivalent for this additional burthen, i he
fum, given by way of equivalent, was ordained to be
paid for certain purpofes, and to certain perfons or bo¬
dies corporate, mentioned in the articles of umon and
in pollerior ftatutes. The proprietors of thefe turns, to
the extent of 248,550!. Sterling, were ereded into a
body corporate, under the name of the Equivalent Lom-
panv ; and the laid fum of 248,550!. was declared to be
the joint flock of the company. Upon application by
this company, they obtained a royal charter, empower¬
ing fuch of them as inclined to fubfenbe their fhares
in the joint flock for that purpofe, to carry on the bufi-
nefs of banking. By this charter the fubfenbers to this
banking bufinefs were, in A. D. 1727, erefted into a
body corporate, to be called, “ The Royal Bank of Scot-
land:' They were veiled with the reqmfite powers,
and the management of the company’s affairs declared
to be in a governor, deputy governor, nine ordinary and
nine extraordinary directors. The qualifications of
thefe managers were declared to be, that of the gover¬
nor to hold flock to the extent of 20061.5 of the depu¬
ty governor, of 15O01.5 of the ordinary directors, o
loool.j and of the extraordinary direftors, of 500b
The fum originally fubferibed was ill ,oool.} but by
a charter palled in favour of the Royal Bank, A. D.
1738, explaining the privileges formerly bellowed up¬
on them, and enabling them to increale tneir capital,
they were empowered to raife their flock to a min not
exceeding in whole, when joined to their original funds,
150,000k By the charter of eredion of this company,
a fhare of 300k entitles a proprietor to one vote, one ot
■book to two, of 1200k to three, and of 2000k to
four*, and no proprietor can have more than four
votes. . , ‘ 1 e
34. “ The Britijh Linen Company, with a capital ot
100,000k was incorporated by royal charter in I74^»
with a view to encourage the manufacture of linen in
Scotland. By the conflitution of this company, its affairs
•are declared to be under the management of a governor,
deputy governor, and live directors. It is declared a ne-
celfary qualification in the governor to be polfelfed of
a fhare in the company’s flock to the amount of
loool. j of the deputy governor, 500I. j and of eadi
direftor, of 300I. A fhare of 200I. entitles a proprie¬
tor to vote in the choice of thefe managers, of 500k
to two votes, and of 1000I. to four votes j but it is de¬
clared that no proprietor fliall polfefs more than four
'votes. .
“ This company carries on the bufinefs of banking,
and ilfues promiffory notes like the two former com¬
panies •, but the banking bufinefs is carried on feparately
from the linen trade. The Linen Hall remains in the
Canongate , but the apartments of the bank are removed
to a lane on the fouth fide of the High flreet, above
what was called the Nether-bow port.
“ Promilfory notes, payable on demand, have ajfo
been long ilfued in Edinburgh by a private banking
houfe, that of Sir William Forbes, Sir James Hunter,
VOL» VII. Part II.
extenfive circulation. . . .
“ Befides thefe there are feVeral private banking
houfes of great reputation in Edinburgh, which do
not iffue promilfory notes for fmall fums payable on
demand, but which carry on the other branches GiBcautmf
uenmnu unv whav** ^j v** -— -
the banking trade, by tranfmitting money, difexiunt- Scctland, I.
ing bills, and accommodating individuals with cafh ac-9 •
counts ^
It now remains only to fpeak fomething of the re-Religious
ligious and civil eltablifhments of this metropohs e^abhlh.
The highefl of the former is the General Aflembly of
the Church of Scotland, who meet here annually in the
month of May, in an aide of the church of St Giles
fitted uo on purpofe for them. I he throne is filled by
a commiffioner from his majefty, but he neither debates
nor votes. He calls them together, and diffolves them
at the appointed time in the name of the king y but
they call and diffolve themfelves in the name of the
Lord Jefus Chrift. This affembly confifts of 352.
members chofen out of the various prefbyteries throug 1-
out the kingdom 5 and the debates are often very m-
terefting and eloquent. This is the fupreme eccle-
fiaftical court in Scotland, to which appeals lie front
the inferior ones. . r
The ecclefiaftical court next in dignity to the ai-
fembly is the Synod of Lothian and Iweeddale, who
meet in the fame place in April and November j and
next to them is the Prelbytery of Edinburgh. Theld
meet on the laft Wednefday of every month, and are
truftees on the fund for minifters widows. They have
a hall in Scott’s clofe, where there is a good pifture
of Dr Webfter by Martin, which was put up
the expence of the truftees, out of gratitude^ for the
trouble he took in planning and fully eftabliftnng the
fun(h , ,
The Society for propagating Chriftian Knowledge
in the Highlands and Ifiands of Scotland, was efta-
blifhed a body corporate by Queen Anne in the year
1709, for the purpofe of erecting fchools to inftrucl
poor children in the principles of Chriftianity, as well
as in reading and waiting. T he fociety have a haU m
Warrifton’s clofe where their bufinefs is tranfaCted.
From time to time they have received large contribu¬
tions, which have always been very properly applied ;
and for much the fame purpofe his majefty gives 1000I.
annually to the general affembly of the church or
Scotland, which is employed by a committee of their
number for inftructing the poor Highlanders in the
principles of the Chriftian religion.
The Erfe church at Edinburgh was built about
^ o years ugo by (ubfcriptions for the fame laudable
purpofe. Great numbers of people rrfort to the me¬
tropolis from the Highlands, who underftand no other
language but their oVvn, and confequently have no op¬
portunity of inftruftion without it } and a moft re¬
markable proof of the benefit they have received fiom
it is, that though the church is capable of holding
1000 people, yet it is not large enough for thofe who
apply for feats. The minifter has 100k per annum
arifing from the feat rents, and holds communion with
the church of Scotland. The eftablilhment was pro¬
moted by William Dickfon dyer in Edinburgh. 30
With regard to the political conftitution ot Edin- Political
burgh, the town council have the direaion of all pub-conlUnw
6 ’ 3 Y lie110"1
EDI L 53
Edinburgl). lie affairs. The ordinary council coniuls only of 25
perfons ; but the council ordinary and extraordinary, of
33. The whole is compofed of merchants and tradef-
mcn, whole reipeclive powers and interefls are fo in¬
terwoven, that a balance is preferved between Use two
bodies. The members oi the town council are partly
eledled by the members of the 14 incorporations, and
they partly choofe their own fucceffors. The eleciion
is made in the following manner : Firft, a lift or leet of
fix perfons is made out by each incorporation j from
which number, the deacon belonging to the incorpo¬
ration mull be chofen. Thefe liils are then laid before
the ordinary council of 25, who “ Ihorten the leeis”
by expunging one half of the names from each ; and
from the* three remaining ones the deacon is to be
ehofen. When this eleftion is over, the new deacons
are prefented to the ordinary council, who choofe fix
of them to be members of their body, and the fix dea¬
cons of lafl year then walk off. The council of 25
next proceed to the election of three merchant and
two trades councilors. The members of council, who
now amount to 33 in number, then make out leets,
from which the lord provoft, dean of guild, treafurer,
and bailies, muft be chofen. The candidates for each
of thefe offices are three in number 5 and the eleciion
is made by the 30 members of council already men¬
tioned, joined to the eight extraordinary council dea¬
cons.
The lord provoft of Edinburgh, who is fly led right
honourable, is high fheriff, coroner, and admiral, within
the city and liberties, and the town, harbour, and road
of Leith. He has alfo a jurifdiction in matters of life
and death. He is prefes of the convention of royal
borought, colonel of the trained bands, commander of
the city guard and of Edinburgh jail. In the city he
has the precedency of all the great officers of Hate and
of the nobility ; walking cn the right hand of the king
or of his majefty’s commiffioner ; and has the privilege
of having a fword and mace carried before him. Un¬
der him are four magiflrates called bailies, whofe office
is much the fame with that of aldermen in London.
There is alfo a dean of guild, who has the charge of
the public buildings, and without whofe warrant no
houfe nor building can be erected within the city. He
has a council to confult with, a nominal treafurer, who
formerly had the keeping of the town’s money, which
is now given to the chamberlain. Thefe feven are
elected annually 5 who with the feven of the former
year, three merchants and two trades counfellors, and
14 deacons or prefes of incorporated trades, making in
all 33, form the council of the city, and have the foie
management and difpofal of the city revenues 5 by
which means they have the difpofal of places to the
amount of 20,000!. annually. Formerly the provoft
was alfo an officer in the Scots parliament. The ma-
giftrates are ffieriffs-depute and jullices of the peace ;
and the town council are alfo patrons for all the churches
in Edinburgh, patrons of the univerfity, and electors
of the city’s reprefentative in parliament. They have
befides a very ample jurifdidtion both civil and crimi¬
nal. They are fuperiors of the Canongate, Portfhurgh,
and Leith ; and appoint over thefe certain of their own
number, who are called baron bailies : but the perfon
who prefides over Leith has the title of admiral be-
8 ] EDI
caufe he hath there a jurifdiction over maritime affairs. Ediab
The baron bailies appoint one or two of the inhabi- *
tants of their refpective diitridts to be their fubftitutes,
and theie are called rejident bailies. They hold courts
in abfence of the baron bailies, tor petty offences and
difeuffing civil caufes of little moment.
No city in the world affords greater fecurity to the
inhabitants in their perfons and properties than Edin¬
burgh. Robberies are here very rare, and ffreet murder
hardly known in the memory of man 5 lo that a perfon
may walk the ftreets at any hour of the night in per¬
fect fecurity. This is in a great meafure owing to the , £
town guard. This inftitution originated from the con-Tow *
fternation into which the citizens were thrown after the gu -rT
battle at Flowden. At that time, the town council
commanded the inhabitants to affemble in defence of
the city, and every fourth man to be on duty each
night. This introduced a kind of perfonal duty for
the defence of the town, called watching and warding ■
by which the trading part of the inhabitants were ob¬
liged in perfon to watch alternately, in order to pre¬
vent or fupprefs occafional difturbances. This, how¬
ever, becoming in time extremely inconvenient, the
town council, in 1648, appointed a body of 60 men to
be raifed 5 the captain of which was to have a monthly
pay of ill. 2s. 3d. two lieutenants of 2I. each, two
ferjeants of il. 5s. and the private men of 15s. each.
No regular fund was eftabliffied for defraying this
expence : the confequence of which was, that the old
method of watching and warding was refumed but
the people on whom this fervice devolved were
now become fo relaxed in their difeipline, that the
magiftrates were threatened with having the king’s
troops quartered in the city if they did not appoint a
fufficient guard. On this 40 men were raifed in 1679,
and in 1682 the number was increafed to 108. After
the Revolution, the town council complained of the
guard as a grievance, and requefted parliament that it
might be removed. Their requeft was immediately
granted, and the old method of watching and warding
was renewed. This, however, was nowT fo intoler¬
able, that the very next year they applied to parlia¬
ment for leave to raife 1 26 men for the defence of the
city, and to tax the citizens for their payment. This
being granted, the corps was raifed which ftill con¬
tinues under the name of the town guard. At prefent
the eftabiifhment confifts of three officers and about
90 men, who mount guard by turns. The officers
have a lieutenant’s pay 5 the ferjeants, corporals, drum¬
mers, and common foldiers, the lame with thofe of the
army. Their arms are the fame with thole of the
king’s forces : but when called upon to quell mobs,
they ufe Lochaber axes, a part of the ancient Scot-
tifti armour now in ufe only among themfelves. 32
The militia or trained band of the city confift of Militia
16 companies of 100 men each. They were in ufe to trained
turn out every king’s birth day j but only the officers bands*
now remain, who are chofen annually. They confift
of 16 captains and as many lieutenants and enligns }
the provoft, as has already been mentioned, being the
colonel.
The towm guard are paid chiefly by a tax cn the
trading people 5 thefe being the only perfons former¬
ly fubjedt to watching and warding. This tax, how¬
ever,
E D I
C 539 1
E D I
33
Syftem ot
police.
Edinburgh, ever, amounts only to i 250L and as ttie expence of
1 v" ' the guard amounts to 1400I. the magi ft fates are obli¬
ged to defray the additional charge by other means.
But in the year 1805, in confequence of a new fyftem
of police being eftablhhed, the city guard was reduced
to one lieutenant, two ferjeants, two corporals, two
drummers, and thirty men, the lord provoft for the time
beincr to be captain, without pay, and the company to
be armed and clothed at the expence of the city, but
their pay to be defrayed out of the general fund railed
under the new police a£t 5 and the duty of this compa¬
ny is to attend upon his majefty’s commiflioner to the
general affembly of the church of Scotland, the magi-
itrates and town council, the fupreme courts of juftice,
and to act in general for the fupport of the new fyftem
of police.
The fyftem of police above alluded to, was eftablilu-
ed in 1805 by a£t of parliament, under the authority of
which the city and fuburbs are divided into fix diltricts
or wards for the more convenient execution of the pui-
pofes to which the aft extends.. The regulations in¬
cluded under this fyftem of police relate to cieanftng
and lighting the ftreets and paflagesin the city and fub¬
urbs, apprehending and punilhing vagrants and difn-
derly perfons, fupprefting common begging, preventing
nuilances and obftrucfions, and for other purpoies con-
nefted with the prefervation of peace and good order.
The management of the whole affairs under this i) hem
of police is entrufted to the general and reiident com-
miliioners. The general commiffioners appointed by
the acl, are, the lord provoft and magistrates of the city
of Edinburgh, with the lord prefident of the court of
feftion, the lord juftice clerk, the lord chief baron of
the court of exchequer, the law officers of the. crown,
and feveral other public characters, in conjunction with
the whole refident commiffioners in the ^different wards.
There are to be feven refident commiffioners in each
ward, the two higheft in the lift to go out, and two o-
thers to be elected in their ftead annually ; the com-
miffioners to be occupiers of houfes valued at twenty
pounds fterling of free rent yearly, excepting in two
wards, where occupying a houfe of twelve pounds rent
is a fufficient qualification. In each ward there are to
be elected by the refident commiffioners, with the ap¬
probation ot the general commiffioners, an infpeCtcr,
and fuch a number of officers of police and watchmen
as may be neceffary, the officers of police and watch¬
men upon duty having the authority and poffeffmg the
powers given by the law of Scotland to the office oi
conftable.
The generalc ommiffioners have the power of chooffng
a fuperintendant or mafter of police for the whole city
and fuburbs included in the aCt, and to appoint a clerk
who (hall do the duty of clerk to the general meetings,
as well as to the court of police to be held by the fu¬
perintendant. The general commiffioners alfo are
authorized to fix the number of officers and watchmen
to be employed in the different wards. The fuperin¬
tendant of police having been appointed by the com¬
miffioners, is to receive from the flieriff depute of the
county of Edinburgh the authority of a fherifffubffitute,
as well as a commiffion of ffieriff depute within the city
and liberties from the lord provoft who is principal
ftieriff within thefe bounds, that the fuperintendant a cl¬
ing as mafter or judge of police may have the full
powers of a magiftrate in the execution of his duty. Edinburg!«
By the powers with which the fuperintendant is invert- v
ed, he may commit offenders to the tolbooth or to
bridewell for a period not exceeding 60 days, and im-
pofe fines for offences not exceeding 40 [hillings fter¬
ling, and give judgment in damages for any fum not
exceeding three pounds fterling with the expences in
either cafe. From the fentences of the fuperintendant
there is no appeal to the iheldff depute of .the county,
or to the lord provoft as ftieriff principal within the ci¬
ty. The fuperintendant of police is alfo the billet-maf-
ter within his bounds, and the infpe£k>rs ot wards are
billet-matters within their feveral wards. The infpec-
tors alfo have the powers of procurator ftfcals with re-
fpe<ft to all profecutions for offences committed witnin
their bounds.
The expences neceffary to carry the above act into
execution, are to be defrayed from a fund railed by
affeffment on the inhabitants of three per cent, on the
free rent of houfes, fiiops or warehoufes, and for the ex-
pences of clothing and alimenting the perfoi.s commit¬
ted to bridewell a farther affeffment not exceeding } per
cent, of the free rent of fuch houfes, &c. For the pur-
pofe of afeertaining rents, iurveyors are appointed j
and if the rent fixed by them ftiould be over-rated,
an appeal may be made to a committee of the general
commiffioners fpecially appointed.
The office of the fuperintendant of police is in the
Lawnmarket. The operation of the aft has only con¬
tinued for a few months (September 1805) and al¬
though fome complaints have been made of its rigorous
execution, arifing probably from fuch unavoidable and
unforefeen circumftances as frequently occur 111 the. efta-
bluhnient of a new fyftem, yet there is every reafon to
hope, that it will prove highly beneficial for the prefer¬
vation of peace and good order in the city and fuburbs
over which it extends. _ 34
The number of inhabitants in the city of Edinburgh Number of
is fomewhat uncertain, and has been very varioufly inhabitants,
calculated. By a furvey made in the year-1775, it
appears that the number of families in the city, Ca-
nongate, and other fuburbs, and the town of Eeith,
amounted to 13,806. Hie difficulty therefore is to fix.
the number of perfons in a family. X)r Price fixes this
number at 4 rT5 j Mr Maitland, at 5 \ and Mr Arnot,
at 6 ; fo that, according to this laft gentleman, the
whole number of inhabitants is 82,836; to which he
thinks 1400 more may be added for thofe in the gar-
rifon, hofpitals, &c.
The following table exhibits a comparative view of
the population of the city of Edinburgh and fuburbs
taken in different years. The laft; enumeration made in
1801 by aft of parliament is fuppofed to be confidera-
bly defeftive in the real amount of the inhabitants, as
an alarm was induftrioufly fpread that it was done with
a view to the impofition of new taxes. This, it appear¬
ed, Induced many to conceal the names and number ot
the individuals in their families.
1678
1722
*755
ins
1791
1801
40,420
57ft95
70i43°
84,886
82,3*60
Y 2
There
EDI C 540 1 * EDI
EfltnVmrgli, There are in Edinburgh 14 incorporations, capable
Edinburgh-0f choofnig their own deacons, viz. The royal college
. 1^t^ of furgepns j the corporations of goldfmiths, Ikinners,
furriers, hammermen, weights and mafons, taylors, ba¬
kers, butchers, fhoemakers, weavers, waukers, bonnet-
-j; makers, and merchant company.
Plenty of The markets of Edinburgh are plentifully fupplied
provTions. -with all forts of provifions. Frefh butcher meat, as
well as fowl and fifh, if the weather permit, may be
had every day 5 and no city can be better fupplied
with garden fluffs. The Edinburgh ffrawberries par.
ticularly are remarkably large and fine. A fink¬
ing infiance of the plenty of provifions with which
Edinburgh is fupplied was obferved in the year 1779,
when feveral large fleets, all of them in want of ne-
cefiaries, arrived in the Forth, to the amount of
about 500 fail, and having on board at leaft 20,000
men; yet the increafed confumption of provifions,
which certainly enfued upon the arrival ol fo many
ftrangers, made not the leaft increafe in the rate of the
markets, infomuch that feveral viftualling ftiips fent
down by the navy board returned without opening
their hatches. The city mills are let to the corporation
of bakers in Edinburgh 5 and the bread made in the
city is remarkable for its goodnefs.
Edinburgh is fupplied with wTater brought for fome
miles in pipes, and lodged in two refervoirs, from
wdience it is diftributed through the city both to
public wells and private families. A revenue accrues
to the town from the latter, which muft undoubtedly
increafe in proportion as the city extends in magni¬
tude.
There are but few merchants in Edinburgh, moft of
them refiding at the port of Leith ; fo that the fup-
port of the city depends on the confumption of the
neceffaries as well as the fuperfluities of life. There
are five different forts of people on whom the fhop-
keepers, publicans, and different trades depend : 1. The
people of the law, who are a very refpeftable body in
the city. 2. The number of young people of both
fexes who come to- town for their education, many of
the parents of whom come along with them. 3. The
country gentlemen, gentlemen of the army and navy,
and people who have made their fortunes abroad, &c.
all of whom come to attend the public diverfions, or
to fpend their time in fuch a manner as is moft agree-
• .able to them. 4. The vaft concourfe of travellers from
all parts. 5. Moft of the money drawn for the rents
of country gentlemen is circulated among the bankers
or other agents.
At Edinburgh there are excellent manufactures of
linen and cambrics} there are alfo manufactures of
paper in the neighbourhood, and printing is carried on
Very extenfively. But for fome time the capital branch
about Edinburgh has been building : which has gone
on, and ftill continues to do fo, with fuch rapidity,
that the city has been increafed exceedingly in its ex¬
tent $ and it is not uncommon to fee a houfe built in
a few months, and even inhabited before the roof is
quite finifhed.
EDINBURGHSHIRE, or Midlothian, is bound ¬
ed on the north by the frith of Forth and the river
Amend, which divides it from Weftlothian or Linlith¬
gow •, on the eaft by Haddingtonlhire 5 on the fouth by
the counties of Lanark, Peebles, and Berwick $ and at
the weft corner by part of the county of Linlithgow. Edinfiurgh-
It extends about 30 miles in length, and its breadth
varies from 16 to 20; containing in all about 360 v
fquare miles, or 230,400 Englifti acres. The furface
of the country is pleafant, having much level ground,
interfperfed with fome hills, watered with many agree¬
able ftreams, and ftieltered and decorated with woods.
The arable land, which may be calculated about one
third of the whole, is in a ftate of high cultivation, and
affords excellent crops. The two great ridges of hills
which pafs through the county, called the Moorfoot and
the Pent/and hills, afford pafture j the former is far
fuperior in quality to the latter : in thefe hills it is ge¬
nerally remarked that the north fide of the hill is the
fineft and beft pafture, contrary to what we Ihould be
apt, a priori, to imagine. Like the other parts of the
country, this diftrict experiences the confequences of an
infulated fitution ; being fubjedt to that inftability and
uncertainty, that the climate in one day exhibits the
weather of every feafon of the year ; the cold eaft winds
in the fpring are exceedingly detrimental to fruit, and in
autumn the hears or mills from the fea, are apt to
whiten and wither the corns before they are ripe. The
immediate vicinity of many of the farms to the metro¬
polis affords the opportunity of procuring ftreet dung-
eafily, and has been of material advantage in improving
the land 5 it has this difadvantage, however, that by
long continuance the fields become very full of weeds,
particularly the /caller or wild muftard *, it is imagined
that this would be obviated by throwing the field out
in pafture for a few years, and afterwards liming it well
before ploughing. The chief rivers of the county of
Edinburgh, are the North and South Ejhs, which, unit¬
ing, fall into the frith of Forth at the town of Muffel-
burgh •, the Amond, which falls into the fame frith at
the village of Cramond, and the water of Leith, which
forms the harbour of that towm : all of thefe abound
with trout. The iflands of Inchkeith and Cramond,
and of Inchmickery, alfo belong to this county. Few
diftrifls of Scotland afford more minerals than the coun¬
ty of Edinburgh 5 it abounds everywhere with coal,,
limeftone, and freeftone of fuperior quality •, and iron
ore of different fpecies is very abundant} compound
ftone, called petuntfe, is found in great quantity in the
Pentland hills, and has been fuccefsfully employed in.
the manufadure of Britilh porcelain. In the pariffr
of Ratho is found a fine fpecies of whetftone or hone j
and in the parifti of Duddingftone, at Brickfield, is found
clay, fit for making earthen wrare. The hills are com-
poled of porphynj and bafaltic whin/one, wdrich in
many places, particularly Arthur’s Seat and Craig-
Lockhart, exhibit regular forms. Near Glencrofs, and in
the Braid-hills, are found great veins of the heavy fpar,
or barytes, which is often an attendant on metallic
veins, efpecially of lead and copper. All the hills con¬
tain fpecimens of zeolites, jafpers, fpars, &c. From the
vicinity to the metropolis, numerous feats of nobility
and gentry are everywhere to be feen. Befides the
city of Edinburgh and its fuburbs, in which we may in¬
clude the towm of Leith, this county contains feveral
large towns and villages, as Dalkeith, Muffelburgh, Li-
berton, Laffwade, and Gilmerton, and is divided into
31 pariihes, of which the following is the population at
twro different periods.
Parijhes*
EDO
[
£(Hnburgh-
fljire
II
Edom.
Pdrijlcu
[ Bortliwick
Calder, Weft
Canongate
Carrington
5 Cpckpen
Colingtown
Corftorpkine
Cramond -
Cranftoun
Crichton
Currie
Dalkeith
Duddingfton
Edinburgh
Fala
Glencrofs _■
Heriot
Inverefl-i
Kirknewton
Laflwade
Leith, North
Leith, South
Libbertoun
Midc alder
Newbottle
Newton
Pennycuick
Ratho
St Cuthberts
30 Stow
31 Temple
10
15
20
Population
in D55-
9XO
1294
45co
555
640
792
995
1455
725
611
1227
31x0
989
3 x ,122
312
557
209
4645
ii57
2190
2205
7200
2793
1369
1439
1 *99
890
93°
12,193.
1294
9°5
9°,412
Population in
1750—1798.
858
I 289
6200
329
1123
I395
1037
M85
839
900
1300
4366
910
31,898
372
385
3°o
5392
812
3000
2409
IL432
3457
1251
*295
1 *35
1721
825
32,947
1400
593
Red lea, Edmund,
Education,
122,655
90,412
Increafe, 32,243
EDITOR, a perfon of learning, who has the care
of an impredion of any work, particularly that of an
ancient author : thus, Erafmus was a great editor •, the
Louvain doftors, Scaliger, Petavius, F. Sirmond, Bi-
(hop Walton, Mr Hearne, Mr Ruddiman, &c. are
likewife famous editors. ,
EDOM, or Esau, the fon of Ifaac and brother 01
Jacob. The name of Edom, which fignifies/W, was
given him, either becaufe he fold his birthright to
Jacob for a mefs of red pottage, or by reafon of the
colour of his hair and complexion. Idumaea derives
its name from Edom, and is often called in Scripture
the land of Edom. See the next article.
Edom, or Idum$a, in Ancient Geography, a diftncl
of Arabia Petraea y a great part alfo of the fouth ot
Judaea was called Idumcea, becaufe occupied by the
"idumaeans, upon the Jewilh captivity, quite to Hebron.
But the proper Edom or Idumaea appears not to have
been very extenfive, from the marcly of the Ifraelites, in
which they compaffed it on the fouth eaftwards, till
they came to the country of the Moabites. Within
this compafs lies Mount Hor,_ where Aaron died y
marching from which the Ifraelites fought with King
Arad the Canaanite, who came dowm the wildernels
againft them (Mofes). And this is the extent of the
Idumcea Propria lying to the fouth of the Dead .ea y
54T 1 . E U u
but in Solomon’s time extenaing to t e
^1 EDMUND L and II. See (HiJionj 0/) England. t
EDUCATION maybe defined, that ienes ot means DefinkicE>i
by which the human undemanding is gradually en¬
lightened, and the difpofitions of the human heart are
formed and called forth between earlieft infancy and
the period when we confider ourfelves as qualified to
take^a part in acdive life, and, ceafing to direft our
views folely to the acquifition of new knowledge oi
the formation of new habits, are content to act upon
the principles which we have already acquired. Parti*u!ar*
This comprehends the cxrcumftances of.the,^ , Lnpre-
regard to local fituation, and the manner in which the het ded un_
neceffaries and conveniencies of life are fupplied to himjder lhede -
the degree of care and tendernefs with which he is fimtion.
nurfed m infancy y the examples fet before him by
parents, preceptors, and companions y Uie degree o.
reftraint or licentioufnefs to which he is accuftome ,
the various bodily exercifes, languages, arts and ici-
ences, which are taught him, and the method and or¬
der in which they are communicated y the moral, and
religious principles which are mftilled into, his mind y
and even the ftate of health which he enjoys during
that period of life. . .3
In different periods of foc.ety, m different cbmates. Various
and under different forms of government, various
tutions have naturally prevailed in the education ot^^^
youth y and even in every different family, the children vaped.
are educated in a different manner, according to the
differences in the fituation, difpofitions, and abilities,
of the parents. The education of youth being an
obieft of the higheft importance, has not only engaged
the anxious care of parents, but has hkewife. often at-
trafted the notice of the legifiator and the philofopher 4
What our readers have therefore a right to expect plan,
from us on this article is, I ft. That we give an ac¬
count of feme of the molt remarkable mftitutions for
the education of youth which have been legally efta-
blifhed or have accidentally prevailed among various
nations and in various periods of fociety.. 2dly, I hat
we alfo give fome account of tne moft judicious and
the moft fanciful plans which have been propofed by
thofe authors who have written on the fubjeft of edu¬
cation. And, laftly, That we venture to prefent them
with the refult of our own obfervations and recolkaions
on this important head.. . 1 r-j
In the infancy of fociety, very little attention can beEducauon
paid to the education of youth. Before men have”- .- S
rifen above a favage ftate, they are almoft entirely the
creatures of appetite and inftma. The impulfe of
appetite hurries them to propagate their fpecies. The
power of inftinaive affeaion is often, though not al¬
ways, fo ftrong as to compel them to preierve and
uurfe the fruit of their embraces. But even when
their wants are not fo urgent, nor their hearts fo^e-
ftitute of feeling as to prompt them to abandon their
new-born infants to the ferocity of wild beafts or the
feverity '.of the elements, yet ftill their uncomfortable
and precarious fituation, their ignorance of the law s ot
nature, their deficiency of moral and religious princi¬
ples, and their want of dexterity or fkill m any of the
arts of life y all thefe together muft render them unable
to regulate the education of their chi dren with much
attention and fagacity.. They may relate to thein the
«5
E E> U
fi "■ \vl 14pi*rrco;iHAent tales, in which
ccrning fuperior beings, and all their knowledge of the
circumilances and tranlaiflions of their ancelfors, are
contained j they may teach them to bend the bow, to
point their arrows, to hollow the trunk of a tree into a
canoe, and to trace" the almoft imperceptible path of
an enemy or a wild beaft over dreary mountains or
through intricate forefts : but they cannot imprefs
tneir minds with juft ideas concerning their fecial rela¬
tions, or concerning their obligations to a Supreme
Being, the framer and upholder of nature 5 they teach
them not to reprels their irregular appetites, not to re-
ftram the fallies of paftion when they exceed juft bounds
or are improperly direfled ; nor can they inform their
underftandings with very accurate or extenftve views
of the phenomena of nature. Befides, they know not
how far implicit obedience to bis parents commands
is to be required of the boy or youth, nor how far he
ought to be left to the guidance of his own reafon or
humour. Among favages the influence of parental
authority foon expires, nor is the parent felicitous to
maintain it. As the eagle expels his young from his
lofty neft as foon as they become able to fupport them-
felves in the air •, fo the favage generally ceafes to care
for his child, or aliume any povrer over him, as foon as
he becomes capable of procuring the means neceflary
for his own fubfiftence. Savages being fcarce con¬
nected by any focial ties, being unacquainted with the
reftraint of civil laws, and being unable to contribute
m any great degree to the maintenance or protection
of one another 5 each individual among them, as foon
as he attains that degree of ftrength and dexterity
which may enable him to procure the neceflaries of
life, ftands tingle and alone, independent on others,
and fcorning to fubmit to their commands. The pa¬
rent, confcious of his inability to confer any important
benefits on his child, after be has advanced even a
very flsort way towards manhood, no longer endea¬
vours to controul his actions ; and the child proud of
Ills independence, fcarce fubmits to alk his parents ad¬
vice. And even before his reaching this period of inde¬
pendence, fo fewT are the benefits which parents can
beftow (being confined to fupplying the neceflaries of
life, and communicating the knowledge of a very few
of the rudeft fimpleft arts), that children regard them
with little deference, nor do they always infill on im¬
plicit fubmiflion. AY ant of natural affeclion, and con-
Icioulhefs of fuperior ftrength, often prompt the pa¬
rent to abufe the weaknefs of his child. Yet though
Imall the fkill with which the favage can cultivate the
underftanding or form the difpofitions of his child,
though few the arts which he can teach him, and
though not very refpedlful or fubmiflive the obedience
or deferences which he requires : yet there is one qua¬
lity of mmd which the favage is more careful to infpire
than thofe parents who are d'ireifted in educating their
children by all the lights of civilized fociety. That
quality indeed is abfolutely neceflary to fit the favage
for his fituation ; without it, the day on which he
ceared to enjoy the preteflion of his parents would
moll probably be the laft day of his life : That quality
is Fortitude. We may perhaps think, that the hard¬
ships to which the young favage is from the period
of his birth unavoidably expofed, might be enough to
inipire him with fortitude ; but as if thefe were in-
4
[ 542 1 E D U
a 1 their notions con- futiicient, other means are applied to infpire him with EJuca'Br,
what the Stoics have regarded as the firft of virtues. *
He is compelled to fubmit to many hardlhips unne-
ceflary, but from a view to this. Children are there
called to emulate each other ih bearing the fevereft
torments. Charlevoix relates, that he has feen a boy
and girl bind their arms together, place a burning coal
between them, and try who could longeft endure with¬
out (blinking the pain to which they thus expofed
themffclves. ^
Still, however, the young favage owes his education The favage
rather to nature and to the circumftances in which he indebted
is placed, and the accidents which befal him, than to to .
the kindnefs or prudence o£ his parents. Nature has circumftan.
endowed him with certain powers of underftanding, ces for his *
fentiments, fenfations, and bodily organs; he has been education,
placed in certain circumftances, and is expofed to
a certain train of events 5 and by thefe means chieflv,
not by the watchful induftry of inftru£lors, does he be¬
come -fuch as he appears when he has reached the years
of maturity. - _
But man was not defigned by his wife and beneficent Education
Creator to remain long in a favage ftate ; the princi- an im*
pies of his nature incline him to focial life. Reafon, f0
diftinguilhing the fuperior advantages to be enjoyed in dety.
fociety, concurs with the focial principle in his breaft,
in prompting him to feek the company and converfa-
tion of others of the human race. When men enter
into fociety, they always unite their powers and ta¬
lents, in a certain degree, for the common advantage
of the focial body. In confequence of this, laws come
in time to be inftituted 5 new arts are invented 5 pro-
grefs is made in the knowledge of nature ; moral du¬
ties are better underftood and defined ; jufter ideas are
gradually acquired of all our fecial relations ; friend-
fhip, love, filial, parental, and conjugal affedion, all
are heightened and refined. All thefe advantages da
not iqftantly refult from men’s entering into a focial
ftate •, the improvement of the human mind, and the
civilization of fociety, are gradual and progreftive : But
as it is natural for men to unite in a focial date, fo it is
no lefs natural for fociety to be gradually improved and
civilized till it attain a high degree of perfedion and
refinement.
8
When men have attained to fuc'h knowledge and Attcnt'or
improvement as to be entitled to a more honourable to the edu-
appellation than that of favages, one part of their im-cabon of
provements generally confifts in their becoming more a na*
judicious and attentive in directing the education
their youth. I hey have now acquired ideas of de- civiliza-
pendence and fubordination ; they have arts to teach don.
and knowledge to communicate ; they have moral prin¬
ciples to inftil) and have formed notions of their re¬
lation and obligations to fuperior powers, which they
are defirous that their children ftiould alfo entertain.
Their afieiftion to their offspring is now alfo more ten¬
der and conftant. We obferve at prefent in that ftate
of fociety in which ive live, that the poor who can
fcarce earn for themfelves and their children the ne-
ceffaries of life, are generally lefs fufceptible of parental
affedlion, in all its anxious tendernefs, than the rich, or
thofe whom Providence hath placed in eafy circum¬
ftances ; and we may make ufe of this fadl in reafoning
concerning the different degrees of the fame affection
felt by the favage and the member of a civilized focie-
tv.
E D U
[ 54
FJuc.itloru ty. 'I'Ke favage may be confidered us the pool man,
1 v ; who with difficulty procures the necefiaries of Ine even
for himfelf; the other, as the man m affluent circum-
-ftances, who is more at leifure to liifen to the voice cu
tender and generous affeftion. .
In this improved date of fociety, the education of
youth is viewed as an object of higher importance. The
child is dearer to his parent •, and the parent is now
more capable of cultivating the underftanding and rec¬
tifying the difpbfitions of his child. His knowledge
of nature, and his dexterity in the arts of life, give him
more authority over a child than what the favage can
poffefs. Obedience is now enforced, and a fyitem of
education, is adopted } by means of wnich the parent
attempts to form his child for adding a part in focial
life. Perhaps the legifluture interferes j the education
of'the vouth is regarded as highly worthy of public
concern': it is coniidered that the foolilh fondnels or
the unnatural caprice of parents may, in the riling ge¬
neration, blaft the hopes of the date.
In reviewing ancient hiitory, we find that this ac¬
tually took place in leveral of the moil ccneDialed go¬
vernments of antiquity. The Perfians, the Cretans,
and the Lacedemonians, were all of them too anxious
to form their youth for dilcharging the duties of citi¬
zens to intruft the education of the children .olely to
the parents. Public eftahliffiments were formed among
thofe nations, and a feries of inftitutions enacted, for
carrying on and regulating the education of their
youths: Not fuch as our European univerfities, in which
literary knowledge being the foie object of puiluit,
the ftudent is maintained iolely at his parents expence,
Public e-
ftablifti-
ments for
education
among the
ancients.
Among the
ancient
Periians.
and attends only if his parents think proper to fend
him j but of a very different nature, and on a mucn
more enlarged plan.
The Perfians, according to the elegant and accurate
account delivered by Xenophon in the beginning. ot
his Cyropsedia, divided the tvhole body of their citi-
zens into four orders the boys, the youth, the nnl-
grown men, and thofe who were advanced, beyond that
period of life during which military fervice was requir¬
ed. For each of thefe orders particular halls were
appropriated. Each of them was fubjeefed to the in-
fpeclion of twelve rulers. The adults and the Super¬
annuated were required to employ themlelves in the
performance of particular duties, fuitable to tneir age,
their abilities, and their experience j while the boys
and the youth were engagecl in fuch a courfe of edu¬
cation as feemed likely to render them worthy and ufe-
ful citizens. > . .
The boys were not employed, in their places or m-
itru&ion, in acquiring literary accompliffiments y cor to.
fuch the Perfians were ftrangers. 'They went thither
to learn juflice, temperance, modefty $ to Ihoot the
bow, and to launch the javelin. The virtues and the
bodily exercifes were what the Perfians laboured to
teach their children. Thefe were the direch, and net
fubordinate, purpofes of their fyftem of education. The
mailers ufed to fpend the greatell part of the day in
difpenfing juilice to their fcholars j who carried before
them aflions for thefts, robberies, frauds, and other
fuch grounds of complaint againil one another. Such
were the means by which the Perfians endeavoured to
inftil, even in early youth, a regard for the laws of na¬
tural equity, and for the inilitutions of their country..
J E D u
Till the age ot 16 or 17, the boys were baneu in a(" 1'““'" "
quiring thole parts of education. At that period they
ceafed to be coufidered as boys, and were railed to t>n.
order of the youths. Alter they entered this ordei,
the fame views were itill attended to in the carrying
on of their education. They were Hill inured to bo¬
dily labour. They were to attend the magiftrates, and
to be always ready to execute their commands. They
were led out frequently to the chafe j and on fuch ex¬
peditions they were always headed by the king, as in
time of war. Here they were taught to expole them-
felves fearlefsly to danger ; to fuffer, without repining
or complaint, hunger, third, and fatigue j and to con¬
tent themfelves with the coarfeit, fimpleit fare, lor re¬
lieving the neceflities of nature. In ihort, whether a;
home or out on lome hunting expedition, they weie
conllantly employed in acquiring new Ik ill and dexte¬
rity in military exercifes, new vigour oi mind and
body, and confirmed habits of temperance, fortitude,
abltinence, patience, patriotifm, and noble^ integrity.
After fpending ten years in this manner, tneir courie
of education was completed j they were admitted into
the clafs of the adults, and were elteemed qualified for
nublic offices. It mult not eicape our notice, tnat
the citizens were not compelled to fend theii children
to pals through this courfe of education in the public
halls j but none except fuch as paffed through this,
courie of education were capable of Civil power, or au-
mitted to participate in public offices or public ho -
nours. ^ .
Such are the outlines ot that fyiiem of education
which Xenophon reprefents as publicly eltablilhed
among the Perfians. Were we able to preferve in a
tranilation all the manly and graceful limplicity of that
enchanting author, we would have offered to the per
ulal of our readers the paffiiye in which he has deft iii>-
ed it : but confcious of
we have prefumed only to extract
which it contains. . _ I1:
Perhaps, however, this fyllem of education did not t^einai]<s
fubfift precifely as the eloquent difciple oi Socrates de- jr» Xeno-
feribes it among that rude and fimple people. On p'ron’s ac-
other occalions he. has commemorated iuch milances of ^
being inadequate to that talk,
information
their barbarity, as would tempt us to think them inca-^^^.^
pable of fo much order and fo much wifdom. Perhaps,
as the difcoverers of the new would have fometimes
conferred on the inhabitants of that hemilphere, in the
accounts of them with which they entertained their
friends in Europe, amazing degrees of moral and po¬
litical wifdom, of fldll and dexterity in the arts, of in-
duffry and valour, which thofe uncivilized children of
nature were afterwards found not to poflefs; fo the
Athenian philofopher has alfo aferibed to the Perlians
prudence and attention in regulating the education of
their youth beyond what people in fo rude a Hate can
poffibly exert..
But' if we examine into the principles on which this
fyffem of education proceeds, without concerning our—
felves whether it once actually prevailed among the
Perfians, or is the produclion of the fine imagination
of Xenophon, we will find it peculiarly fuitable for a
nation juft emerging from the rulencfs and ignorance
of barbarity to a knowledge of focial and civil rela¬
tions, and of the duties connected with fmh relation*.
They have facrificed their independence to obtain the
comfort
f
£ £> U [ 544 ] £ t) U
Jl.’ucation. comfort and fecurity of a focial date. They now
'' " “ v glory in the appellation of citizens, and are defirous to
difeharge the duties incumbent on a citizen. They
mult inform their children in the nature of their focial
relations, and imprefs them with habits of difeharging
their focial duties *, otherwife the lociety will foon be
diffolved, and their pollerity will fall back into the
fame wild miferabie date from which they have emer¬
ged. But perhaps the circumdances, or abilities, or
difpofitions of individuals* render them unequal to this
weighty talk. It becomes therefore naturally an ob-
of public care. The whole focial body find it ne-
ceffary to deliberate on the mod proper means for dif¬
eharging it aright. A plan of education is then form¬
ed ; the great objeft of which is, to fit the youth for
difeharging the duties of citizens. Arts and fciences
are hitherto almod wholly unknown : and all that can
be communicated to the youth is only a fkill in fuch
exercifes as are neceffary for their procuring fubfiltence,
or defending themfelves againd human enemies or
beads of prey *, and habits of performing thofe duties,
the negleft of which mud be fatal to the fociety or the
individual.
Such is the fydem of education which we have furvey-
ed as edablidred among the Perfians 5 and perhaps we
may now be lefs fufpicious than before of Xenophon’s
veracity. It appears natural for a people who have reach¬
ed that degree of civilization in which they are deferib-
ed, and have not yet advanced farther, to inditute
fuch an edablifliment. Some fuch edablilhment alfo ap¬
pears necefiary to prevent the fociety from falling back
into their former barbarity. It will prevent their vir¬
tue and valour from decaying, though it may perhaps
at the fame time prevent them from making any very
rapid progrefs in civilization and refinement. Yet the
•indudry, the valour, the integrity, and the patriotifm
which it infpires, mud neceffarily produce fome favour¬
able change in their circumdances; and that change in
their circumdances will be followed by a change in
1 z their fydem of education.
Among the The Cretans, too, the wifdom of whofe laws is fo
Cretans. much celebrated in the records of antiquity, had a
* public edablidiment for the education of their youth.
Minos, whom they revered as their great legiilator,
was alio the founder of that edablilhment. Its tendency
Was fimilar to that of the courfe of education purfued
among the Perfians,—to form the foldier and the citi¬
zen. We cannot prefent our readers with a very par¬
ticular or accurate account of it 5 but fuch as we have
been able to procure from the bed authorities we think
it Our duty to lay before them.
The Cretans were divided into three clalfes j the
boys, the youth, and the adults. Between feven and
feventeen years of age, the boy was employed in learn¬
ing to dioot the bow, and in acquiring the knowledge
of his duties as a man and a citizen, by lidening to
the converfation of the old men in the public halls,
and obferving their conduft. At the age of feven, he
was conduced to the public halls to enter on this
courfe of education. He was taught to expofe himfelf
boldly to danger and fatigue •, to afpire after Ikill and
dexterity in the ufe of arms and in the gymnadic ex¬
ercifes *, to repeat the laws and hymns in honour of
the gods. At the age of feventeen he was enrolled
.among the youth. Here his education was dill con-
3
tinued on the fame plan. He was to exercife himfel/ Educatiart-
among his equals in hunting, Wredling, and the mill- v" J
tary exercifes j and while thus engaged, his fpirits
were roufed and animated by drains of martial mufic
played on fuch indruments as were then in ufe among
the inhabitants of Crete. One part of the education
of the Cretan youth, in which they were partici Jarly
defirou's to excel, was the Pyrrhic dance ; which was
the invention of a Cretan, and confided of various mi¬
litary evolutions performed to the found of indru¬
ments.
Such were the principles and arts in which the Cre¬
tan legiilature direfted the youth to be indrudted.
This courfe of education could not be directed or fu-
perintended by the parent. It was public, and car¬
ried on with a view to fit the boy for difeharging the
duties of a citizen when he diould • attain to man¬
hood. 13
It is eafy to fee, that fuch a fydem of education Remarks
mud have been indituted in the infancy of fociety, be- ^ ^
fore many arts had been indented, or the didinCtions of CHt on ec J
rank had arifen •, at a time when men fubdded in a con-
fiderable degree by hunting, and when the intercourfe
of nations was on fuch a footing, that war, indead of
being occafional, was the great bufinefs of life. Such
a fydem of life would then naturally take place, even
through no fage legiflator had arifen to regulate and
enforce it. 14
Lycurgus, the celebrated lawgiver of Lacedemon, Among the?
thought it neceffary to direCt the education of youth
in a particular manner, in order to prepare them for
paying a driCI obedience to his laws. He regarded
children as belonging more properly to the date than
to their parents, and wilhed that patriotifm diould be
dill more carefully cheridied in their breads than filial
affeftion. The fpirit of his fydem of education was
pretty fimilar to that of thofe which we have jud view¬
ed as fubfiding among the Perfians and the Cretans.
As foon as a boy was born, he was fubmitted to the
infpeftion of the elders of that tribe to which his pa¬
rents belonged. If he was well diaped, drong, and
vigorous, they direfted him to be brought up, and
affigned a certain portion of land for his maintenance.
If he was deformed, weak, and fickly, they condemn¬
ed him to be expofed, as not being likely ever to be¬
come an ufeful citizen. If the boy appeared worthy
of being brought up, he was intruded to the care of
his parents till he attained the age of feven years ; but
his parents were ftriclly charged not to fpoil either his
mind or his bodily conditution by foolidi tendemefs.
Probably, too, the date of their manners was at that
time fuch as not to render the injunftion peculiarly ne¬
ceffary.
At the age of feven, however, he was introduced
to a public clafs, confiding of all the boys of the fame
age. Their education was committed to maders ap¬
pointed by the date •, and what was chiefly inculcated
on them in the courfe of it, was fubmiflive obedience
and refpeft to their fuperiors; quicknefs and brevity in
their converfation, and replies to fuch quedions as
were put to them; dexterity and addrefs in perform¬
ing what was commanded them, and firmnefs and pa¬
tience in bearing every pain or hardfhip to which they
might be expofed. One of the means ufed to form
them to habits of aclivity and addrefs, was to permit,
nayj
*5
Remarks.
E D U [ 545 ]
Education, nay, to dirc£l them to commit little a6ls ol theft j the republic
1 ■ V which, if they performed them fo dexterouily as to
avoid detection, they might afterwards boaft of as
noble exploits : but if detefted in fuch enterprises,
the awkward artlefs boy was expofed both to punilh-
ment and difgrace. To avoid the punilhment and dif-
incurred oy being detected in an aft of theft, the
Spartan boy would often fuffer with unihrinking forti¬
tude the fevered torments. It is related of one of them,
that rather than be difeovered with a young fox under
his cloak, which he had ftolen, he fuffered the little
animal to tear open his bowels. Not content with be¬
holding the children Suffer by fubmitting voluntarily
to fuch hardihips, the Spartans alfo endeavoured to
form them to fortitude, by whipping them on their re¬
ligious feftivals, fometimes with Such Seventy that they
expired under the lalh. 1 he Lacedemonian youth
were alfo taught fuch bodily exercifes, and the uie of
fuch warlike weapons, as were neceffary to render them
expert and Skilful foldiers.
They too, as well as the Cretans and Perfians, a-
mong whom we have feen Similar modes ot education
adopted, were to be citizens and foldiers j not hulband-
men, mechanics, artilts, merchants, &c. I heir mode
of education, therefore, was Ample and uniform. Its
aim was, to make them acquainted with the nature of
their focial duties, and to form them to fuch vigour of
body and fuch firmnefs of mind as might render them
fit for the Station in which they were to be placed,^ and
adequate to the part which they were to aft. I his
establishment for education was perfectly confident
with the other parts of that legislature wnich was insti¬
tuted by Lycurgus. Youth educated among the La¬
cedemonians could hardly fail to become worthy mem¬
bers of that fingular republic. Let us not however
regard the Spartans as Singularly inhumane in their
treatment of youth. Let us realcend, in imagination,
to that period in the progrefs of fociety from rudenefs
to refinement, which they had reached when Ly¬
curgus arofe among them. W hat were then their
circumftances, their arts and manners, their moral
principles, and military difeipline ? Not very different
from thofe which the laws of Lycurgus rendered So
long Stationary among them. He, no doubt, reftified
fome abufes, and introduced greater order and equa¬
lity. But man is not to be So eafily metamorphofed
into a new form. As you cannot, at once, raiie an
acorn to a venerable oak j fo neither will you be able
to change the favage, at once, into the citizen. All
the art or wifdom of Lycurgus, even though alfiited
by all the influence of the prophetic Apollo, could
never have established his laws among his countrymen,
had not their charafter and circumstances previously
difpofed them to receive them. But, grant this, and
you mult, of confequence, allow, that, what to us
may appear cruel and inhumane, mult have aftefted
their feelings in a different manner. The change in¬
troduced in the treatment of youth by the establish¬
ment of this fyftem of education was probably recom¬
mended by its being more humane than what before
prevailed. Corrupted as are our manners, and effemi¬
nate our modes of education j yet we would not per¬
haps aft wifely in laying them afide, to adopt in their
ilead thofe of ancient Sparta. But the Spartan edu¬
cation was peculiarly well fitted to form citizens for
Vox. VII. Part II.
E D U
__r of Lycurgus ; it was happily adapted to E.iucatnrT,
the Slate of fociety in which it was introduced. And,
if we Should inquire by what means Lycurgus was
enabled to fix the arts, the manners, and in Short
the civilization of his country, for fo long a period, in
a Stationary Slate -, we would perhaps find reafon to
aferibe that effeft to the public establishment which
he instituted for the education of youth •, to his -
confining the Spartan citizens to the profelnon of
arms, and aSfigning all fervile oifices to tne Helots 4
and to his prohibiting the ufe of gold and filver.
Among thefe however his establishment for education
occupies the chief place. Never was any State adorn¬
ed with more patriotic citizens than thole of Sparta.
With them every private affeftion feemed to be Swal¬
lowed up by the amor patrice: the love of their coun¬
try was at leatt their ruling paffion. Poedaretes being
rejected when he offered himfelf a candidate for a Seat
among the council of three hundred, returned home,
rejoicing that there were in Sparta no fewer than
three hundred whom his countrymen found reafon to
regard as better citizens than himfelf. This was not
a Seeming joy, affumed to conceal the pain which he
fuffered from the difappointment ; it was heartfelt
and fincere. Such were the effefts of their fyitem of
education. 16
When we turn our eyes from the Perfians, the Cre- Education
tans, and the Spartans, to the other nations of anti- 0^" na-8
quity ; .we nowhere behold fo regular a lyltem of pub- t;ons of an.
lie education. Among the Athenians and the Romans, tiquity.
the laws did not defeend to regulate in fo particular a
manner the management of the youth. Thefe nations
gradually emerged from a State of the rudeit barbarity,
to that polished, enlightened, and civilized State which
rendered them the glory and the wonder of the hea¬
then world : but in no part of their progrefs from the
one State to the other do we find any fuch eitablilhment
fubfiiting among them. So various, however, are the
circumstances which form and diverfify the charafter
of nations, that we cannot reafonably conclude, be-
caufe no fuch establishments existed among the Athe¬
nians and Romans, that therefore their existence was
unnatural among thofe nations who pofieffed them.
But though the education of youth was managed in a
different manner among thefe and molt other nations
in the ancient world, than by public establishments,
which detached children from the care of their parents;
yet Still it was everywhere regarded as an objeft of the
highelt importance. As the manners of mankind gradu¬
ally improved to a State of refinement; as the invention
of arts, and the difeovery of fcience, gradually intro¬
duced opulence and luxury ; connubial, parental, and
filial affeftion gradually acquired greater Strength and
tendernefs. Of confequence, children experienced more
of their parents care ; and that care was direfted to
form them for afting a becoming part in life. Ac¬
cording to the circumstances of each nation, the arts
which they cultivated, and the form of govern nent
under which they lived •, the knowledge which they
fought to communicate to their children, and the ha¬
bits which they endeavoured to imprefs upon them,
were difterent from thofe of other nations: And again,
according to the different circumstances, tempers, abi¬
lities, and difpolitions of parents, even the children of .
each family were brought up in a manner different from
3 Z that
E D U
Kducatlm. that in which thofe of other families were
1 he Athenians, the Romans, the Carthaginians, con-
rinr*rri ^or'n r\r — *-1   iT -1 • .i •
. *7
Quint ti¬
ll an.
dueled each of them the education of their youth in a
different manner, becaufe they had each different ob-
jefts in view. But having confidered the molt Angular
effablilliments for education which prevailed in the an¬
cient world, it feems unneceffary for us to defeend to a
particular account of the manner which every nation,
or fantafhc individual, thought proper to purfue in
Bringing up their youth. It will probably be more
ufefal and entertaining to our readers, if we next pre-
ient them with a view of fome of the moll judicious or
fanciful plans of education which have been propofed
by the writers on that 1’ubject.
One of the moft refpedlable writers on education
among the ancients is the celebrated Quin&ilian. He
taught rhetoric in Rome during the reign of Domitian,
and under feveral of the other emperors. When he re¬
tired from the exerciie of his employment as a teacher
of rhetoric, he fpent his leifure in the compofition of a
treatife, not merely on rhetoric, but on the moft pro¬
per means for educating a boy fo as to render him both
an eloquent orator and a good man.
_ In that valuable treatife, he enters into a minute de¬
tail of all that appears to him moft likely to conduce to
thofe important ends.
As foon as the boy enters the world, he would have
the greateft care to be ufed in fele&ing thofe who are
to be placed about him. Let his nurfe have no impe¬
diment of fpeech. It will be happy for him, if his
parents be perfons of fenfe and learning. Let his tu¬
tor, at leaft, poffefs thefe qualifications. As foon as he
attains the diftindf ufe of his organs of fpeech, let him
be initiated in the firft elements of literature. For
as he is capable of diltinguilhing and remembering at
very early age ; fo his faculties cannot poffibly be
employed in a more advantageous manner. And even
at this early period of life, let maxims of prudence
and the firft principles of morals be inculcated upon
his mind by the books which are put into his hands,
and even by the lines which he copies in learning the
art of writing. The Greek language was to the Ro¬
mans in the days of Quin&ilian, what the Latin and
Greek and French are to us at prefent, an acquifition
held indifpenfably neceffary to thofe who afpired to a
liberal education $ and Quinclilian judges it proper
that the boy fliould begin his application to letters
with the Greek language in preference to his mother
tongue.
This judicious writer next examines a queftion which
has been often agitated, Whether a domeftic or a pub¬
lic education is liable to the feweft inconveniences,
and likely to be attended with the greateft advantages?
And he is of opinion, that in a domeftic education the
boy is in danger of being corrupted by injudicious
fondnefs and evil example j is not roufed by the fpur
of emulation j and is deprived of proper opportunities
for acquiring a juft idea of his own power, or that
a&ivity and dexterity which he will afterwards find fo
neceffary when he comes to aft a part in life : While
in a public education, which was preferred by fome of
the moft renowned nations of antiquity, the morals are
not greatly expoled to corruption, emulation is roufed,
friendftvips are formed, all the powers of the mind are
filled forth to juft with new vigour, and the youth is
t 54<J ] E D U
managed, prepared for performing his part on the great theatre Education.
of the world. Quinftilian, therefore, wifties that pa-' v—*•*’
rents would place their children in public feminaries of
education.
When a boy is committed to a mafter’s care, the
mailer’s attention mult be firft direfted to difeover his
difpofitions and the extent of his capacity. Of his
capacity he. will form a favourable judgment, not from
hi t fprightlinefs, nor even from his quicknefs of appre-
henfion, but from his modefty, docility, and virtuous
difpofitions. If the boy poffefs thefe laft qualifica¬
tions, the mailer will rejoice in him, as likely to give
him fatisfaftion and do him honour. According to
his temper and difpofitions, let the boy be treated with
mildnels or feverity ; but never let feverity extend to
blows. Let the boy be allured and led, by the moft
artful and infinuating treatment, to do his duty; there
will then be no occalion to punifir him for neglefting
. -A8 Quinftilian’s profeffed objeft was, not merely to
give , general direftions for forming the heart and cul- •
tivating the undemanding, but to form a particular
charafter in life, the fcholar and the orator 5 he finds
it neceflary to enter into minute details concerning the
manner. in which the boy is to be inftrufted in fpeak-
ing, writing, grammar, and compofition j of which it
does not appear neceflary for us to take particular no¬
tice in this place. Mufic and geometry, he thinks,
ought to make a part of the young orator’s ftudies •
as being ufeful to render him accurate in reafoning^
and capable of relilhing the beauties of the poets. He
is alfo of opinion, that the boy ftiould not be confined
to one branch of ftudy, without being allowed to at¬
tempt others till he have made himfelf mailer of that.
Let feveral parts of literature engage his attention
by turns . let him dedicate a confiderable portion of
his time to them. He may thus acquire habits of in-
duftrious . application w hich will remain with him
through life.
With the tender attention of a good man, this fen-
fible and elegant writer ftill accompanies his pupil
through the courfe of his ftudies; anxioufty infills that
he be placed under a mailer diftinguiftied for purity of
morals, and for no mean abilities in his profeflion ; di-
refts his memory to be ftored with the nobleft paffages
of the poets, orators, and hiftorians} and carefully difi-
cuffes and refutes thoie opinions w’hich reprefent ge¬
nius as above induftry. The remaining part of his
w?rk being employed on the principles of rhetoric,
without containing any thing on the fubjeft of educa¬
tion in general, it is not neceffary that we ihould here
prefent an analyfis of. it to our readers. But fmee
C^umftilian was fo diftinguiihed, not only as a rheto¬
rician, but as an inilruftor of youth, and diiplays fo
much good fenfe and fo lolid a judgment, formed on
long experience, in whatever he advances on the fub¬
jeft of education; we could not, without extreme ne¬
gligence, omit taking notice of him under this ar¬
ticle, and affording our readers an opportunity of
being inftrufted by liftening to his fentiments on this
head.
The name of John Milton is fo much revered in Bri- Milton’s
. . ~ ;   ***v*w.i AtvtlCU ill »
tain, that his lentiments on any fubjeft are intereitine Treatire oft
to Britons. His life was dedicated to ftudy : During Education-
a part of it, he was employed in the talk of icilrufting
youth;
1
E D U
[ 547 1
E D U
Education, youtii; aftd among his other works we find a treatife
11 on education. He had himfelf been educated accord¬
ing to that plan which has long been eitablilhed in the
Englilh univerfities j but with that mode of education
he was not fatisfied. The objeft of his direftions is
chiefly to form a fcholar. He conftdered himfelf as
qualified to exhibit a model of “ a better education,
in extent and comprehenfion far more large, and yet
of time far fhorter, and of attainment far more certain,
than any that had yet been in practice.” The follow¬
ing is the fubftance of his treatife.
As the end of learning is to cultivate our under-
ftandings, and to reftify our difpofitions j therefore the
defign of our applying to the ftudy of languages cannot
be merely that we may commit to memory the words
of which they confilt, or that we may acquire a know¬
ledge of their analogy and ftrufture ; but that we may
enrich our minds with the treafures of wifdom which
they contain. But in the prefent modes of education
this defign does not appear to be kept in viewi 1 he
learner of Latin is burdened with rules, and themes,
and verfes, and orations j but no care is taken to make
him matter of the valuable knowledge which the dailies
contain. And when he advances a little farther, he is
driven into the thorny paths of logic and metaphyfics.
So, when his ftudies are completed, and he is conli-
dered as having received a liberal education, he is al-
moft as deftitute of real knowledge as when he firtt
entered a fchool.
But to render learning truly beneficial, inftead of
the fchool and univerfity education which youth at
prefent receive, let the place of both fchool and uni-
verflty be fupplied by an academy, in which they may
acquire all that is taught at either, except law and phy-
iic. Let the academy afford accommodation for 150
perfons; 20 of whom may be fervants and attendants.
As many academies as are neceffary may be afterwards
erefted on the model of this one. Let the youth
who are introduced into this academy begin their ttu-
■dies with learning the principal rules of grammar from
fome good elementary book. In their pronunciation
of Latin, let them be taught to follow the pronun¬
ciation of the Italians} as that of the Lnglith is in-
diftinft, and unfuitable to the genius of the language.
Next, read to them fome entertaining book on educa¬
tion ; fuch as, the three firft books of Quin&ilian in
Latin, and Cebes, Plutarch, or fome other of the So-
•cratic difeourfes, in Greek-, and be careful to feize
every opportunity of infpiring them, by feafonable lec¬
tures and explanations, with love for learning, admira¬
tion of great and virtuous characters, and a difpofition
to cheerful obedience. At the fame time, but at a
difterent hour of the day, let them be inftruCled in the
rules of arithmetic and the elements of geometry. Be¬
tween fupper and bedtime, inttruCl them in the prin¬
ciples of religion and the facred hiftory. From the
writers on education let your pupils pafs to the authors
on agriculture, to Cato, Varro, and Columella. Be¬
fore half thefe authors be read, they cannot but be
pretty well qualified to read moft of the profe authors
in the Latin language j and they may now, with great
propriety, learn the ufe of the globes, and make them-
felves acquainted with the ancient and modern maps.
Let them, about the fame time, begin the ttudy of
the Greek tongue, and proceed in it as in the Latin :
IS Education.
they will not fail to overcome, in a Ihort time, ail the  
dithculues of grammar j after which they will have ac- L“
cefs to all the treafures of natural knowledge to be
found in Ariftotle and Theophraftus. In the fame
manner they may make themfelves acquainted with
Vitruvius, Seneca, Mela, Cellus, Pliny, and Solinus.
And having thus palled through the principles of arith¬
metic, geometry, aftronomy, and geography, with a
general compact of phyfics j let them next turn their
attention to mathematics, in which they may begin
with the practical branch of trigonometry, which will
ferve as an introdudtion to fortification, architefture,
and navigation. To teach them the knowledge oi
nature, and mftruct them in the arts of life, let them
have the affiftance and inttruclions, not merely of ma¬
tters who are acquainted only with books, but of men
whofe Ikill has been obtained by aftual practice, even
of artitts and mechanics. Next, let the poets obtain
their attention j and they will now read them with eafe
and pleafure. From the poets let your pupils proceed
to the moralitts ; and, after acquainting themfelves
with them, they may be allowed the entertainment of
fome of the bett Greek, Latin, and Italian dramatic
compofitions. From thefe let them proceed to poli¬
tics } let them here ftudy the law of Mofes, the ad¬
mirable remains of the ancient lawgivers of Greece, the
Roman tables, edicts, and pandefts, concluding with
the inftitutions of their mother-country. Now let
them be more particularly inftru£ted in the principles
of theology *, for by this time they may have acquired
the Hebrew language, together with the Chaldee and
the Syriac dialect, and may therefore read the Scriptures
in their original language. When their minds are thus
furnifhed, they will be able to enter into the fpirit of
the nobleft hiftorians and poets. To get by heart,
and repeat in a proper manner, paffages from the
writings of fome of thefe, will have the happieft ef¬
fects in elevating their genius. Let this ftateiy edifice
be crowned with logic and rhetoric. Far different
would be the eftefts of fuch a courfe of education,
from thofe produced by any which is at prefent pur-
fued. We fhould then fee abler writers, more eloquent
fpeakers, and wifer ftatefmen. Similar to this, pro¬
bably, was the courfe taught in the famous fchools of
Pythagoras, Plato, Ifocrates, and Ariftotle. 1 his
would unite the advantages of an Athenian and a Spar¬
tan education : for our pupils ftiould be taught the ex-
ercifes of wreftling and fencing, and the whole military
difeipline. rp
Such are the ideas of our admired Milton on the Remark^,
fubjeft of education. An enthufiaftic admirer of the
fciences, arts, and inftitutions of Greece and Rome $
from his religious and political principles, no friend to
the univerfities ; it was natural for a man of his learn¬
ing and ingenuity, in an age of innovation, and in¬
fluenced by fuch prejudices, to form fuch a projeft as
that which we have furveyed. He feems not to have
refle&ed, that it is neceffary for children to be long
occupied in obtaining a familiar acquaintance with
words, before they can gain from books any know¬
ledge of things j overlooking this circumftance, and
perceiving plainly that the mode of education which
then prevailed confined the attention of youth almoft
wholly to words, he could not but regard the fcheme
which Tie propofed as likely to produce very happy
3 Z 2 effefts.
Education.
*o
Locke’s
Treatife on
Education.
21
Bodily con.
ftitmion.
E I) U [ 548 ] E D U
effe&s. His obfervation, that the appearances of ex¬
ternal nature are among the firft objedls which attract
the attention of youth, which he communicates by di-
refting his pupils to perufe the writers on agriculture
and natural hiilory as near the beginning of their ftu-
dies as poflible } if not altogether juft, yet muft be
allowed to be nearly fo. Perhaps human aftions and
paflions, and the feries of events which happen around
us, are, by the time at which we begin our applica¬
tion to learning, the objefts which moft frequently and
itrongly engage our attention : But the appearances
of external nature are at lead; the next object of our
regard.
Mr Locke, to whofe abilities and noble deftre to be
ufeful to the world his country is fo much indebted,
has written, among other things, on the education of
youth. He was capable of thinking for himfelf 5 but
more deftrous of rendering himfelf ufeful, than of being
admired for Angularity. He is therefore an author to
whom we ought to liften, at leaft, with refpectful at¬
tention. If Quinftilian and Milton had been employ¬
ed as teachers of youth, Mr Locke had been conver-
fant with the world, had inquired into the principles
of human nature, and had no doubt endeavoured to
examine without prejudice the effects of thofe modes
of education of which he difapproves. When we confi-
der, that, to render himfelf ufeful to the rifmg gene¬
ration, he could defcend from the heights of fcience
to tranflate the fables of ./Efop, and to perform other
humble tafks in literature, which a philofopher of
lefs benevolence and virtue would have difdained 5 we
cannot but look with veneration and gratitude on fo
exalted a charafter. In his Treatife on Education,
the two great objects which Mr Locke keeps in view
are, ift, To preferve and ftrengthen the bodily con-
ftitution ; idly, To inform the underftanding with
ufeful knowledge, and to cherifh good difpofitions in
the heart.
In his directions on the firft of thefe heads, he feems
extremely anxious to prevent parents and others in
whofe hands children are placed, from injuring them by
ill-directed tendernefs. Plain fare, Ample and light
clothing, abftinence from phyfic and from ftrong
liquors, he earneftly recommends as the moft judi¬
cious means for preferving and confirming the health
of the child. In all his gratifications let the ftriCleft
moderation be obferved. If you permit him to in¬
dulge pretty freely in lleep, at leaft caufe him to get
up at an early hour in the morning. In one thing,
however, few parents will be willing to comply with
Mi Locke’s advice. He not only direCts that the
child’s feet be frequently bathed in cold water, but
even exprefies a with, that his flioes were always kept
in fuch a condition as to admit water freely. This he
thinks likely to fortify the conftitution of the body
in fuch a manner, as to render him lefs liable, in the
courfe of life, to fuch difeafes as arife from any un-
ufual expoiure to wTetnefs or cold, than others whofe
feet have been more carefully kept dry. Though he
had profecuted his ftudies with a defign to enter into
the profeflion of phyfic, yet fo unfavourable an opinion
did he entertain of the effefts produced by medical pre¬
parations on the human conftitution, that he earneftly
infifts on the parent to beware of adminiftering any of
them to his child. From the defire which Mr Locke Education,
difcovers to have children expofed to hardlhips, and re- ^
{trained from indulgence, in order to confirm the health
and invigorate the conftitution, we may conjeCture him
to have been an admirer of that fevere mode of educa¬
tion which ufually prevails in the earlier periods of the
exiftence of fociety. He feems to have thought, that
if a boy be brought up like a Huron or a Spartan, he
muft necelfarily become robuft and healthy •, without
reflecting, that of thofe children who are lubjeCted to
fuch a courfe of education, too great a proportion are
unable to furvive it : fuch is the natural delicacy of the
human frame. 23
When he turns his attention to the cultivating of Cultivation:
the underftanding, and the forming of the difpofitions,0*Pow"
Mr Locke ftill defervedly claims the regard of the pa- t^e
rent and the preceptor. With a virtuous indignation
he reprobates that negligence and folly by which we
generally corrupt the heart and fpoil the temper of child¬
ren, even in that period of infancy 5 fo as to render
them incorrigible when they advance farther in life.
Their appetites are pampered, all their defires are gra¬
tified : and if we are at any time difpofed to refufe
what they afk, they have an all-powerful engine to
compel our compliance with their wifties. They affail
us wflth tears •, and we then yield to their requefts, how¬
ever hurtful to themfelves or inconvenient to us. We
often ftudiouily inftruCl: them in vicious tricks, and call
forth their evil paflions. At fo early an age, their rage
or cunning can fcarcely injure us ; and wTe reflect not
that habits of peeviftmels and deceit muft be peculiarly
hurtful to themfelves.
But though all the foolilh defires of children ought
not to be gratified, and though we Ihould carefully avoid
leading them into any bad habit 5 yet it is not neceflary
nor prudent to treat them with harflmefs or feverity.
Let them be formed to obedience from their earlieft
years: let them be accuftomed to iubmit implicitly
to the direftion of thofe on wiiom they depend. But
beware of fouring their temper and deprefling their fpi-
rits by harfhnefs : and, on the other hand, remember
that it is no lefs improper to give the boy a habit of
negledling his duty, except when he is allured to it by
the hopes of reward. As he advances towards man¬
hood, and attains the ufe of reafon, you may admit
him to greater familiarity, and allow him to follow' his
own inclinations more than at an earlier period : and if,
inftead of indulging all his freaks in childhood, you have
carefully accuftomed him to obedience and fubmiflion,
without enforcing thefe by improper means, he will now
be able to regulate his conduct wuth feme degree of
prudence.
But while caution is to be ufed in beftowing rewards
and inflifting punifhments, ftill rewards and punilhments
are indifpenfably neceffary in the management of the
child. Infpire your boy wTith a fenfe of fliame, and
with a generous thirft for praife. Carefs and honour
him when he does well: treat him with negle£t when
he a£ts amifs. This conduft will produce much better
effedts than if you were at one time to chide and beat
him 5 at another, to reward him with a profufion of
fw'eetmeats and playthings.
Think not that children are to be taught propriety
of conduct by loading their memory with rules, di¬
refling
E D U [ 549 1
, , q. n11 every particular occarion. in liftlefs indolence,
reamg them l>ow ‘o f cn ve^rpa t ^ ^
reeling' them now xo aei. un r—r ,
Burden them not with rules, but imprefs them with ha-
blBe not defirous of forming them at too early an age
to all that politenefs and propriety of manners wmcl
touwilh to diltinguilh them when they beeome men.
Let them be taught an eafy, graceful carriage of body
but •nvc yourfelf no concern, though they now and
then blunder again!! the puna.lios of good breeding,
time will correct their awkwardnels.
With regard to that important quefhon, whether
children ought to be fent to a public fchool, or are like.y
to be better trained up in a domeftic education m im-
noflible is it for one mailer to extend his attention to a
number of boys, and fo likely is the contagion of vice
to be caught among the crowd of a public fchool, th
a private items more favourable than a public educatio
to virtue, and fcarce lefs favourable to learning
When you refolve to give your fon a domeftic edu
cation, be careful to regulate that domeftic education
in a judicious manner. Keep him at a diftance fiom
evil example : choofe the moft favourable -eafons for
communicating inftruaion : ftrift y enforce obedxence
but never by blows, except m cafe of obftmacy whic
you find otherwife’incurable. If his engagements in
life prevent the parent from fupermtending and di-
reaing his fon’s education perfonally, let him commit
him tog the care of a virtuous and judicious tutor. Let
the tutor be rather a man of experience m the world
than of profound learning j for it is more neceffary that
the pupil be formed for conduamg himfelf with pru¬
dence in the world, and be fortified againft thofe temp¬
tations to which he will be expofed when he enters up¬
on aaive life, than that his head be fluffed with Latin
^Herf^Mr Locke, notwithftanding that his own
mind was ftored with the treafures of Grecian and
Roman literature, takes occafion to declaie himleli
pretty freely againft that application to ancient learn¬
ing, which was then indifpenfably required m the edu¬
cation of youth. He confiders languages and philoio-
phy as rather having a tendency to render the youth
unfit for a£ting a prudent and becoming part m ftte
than forming for it: and he therefore mfifts that thefe
Ihould be but in a fubordinate degree the objeds oi his
attention. . .
Let the tutor encourage the child under his care to
a certain degree of familiarity j let the pupil be accu-
ftomed to give his opinion on matters relative to him¬
felf : let him be taught juftice, by. finding injuftice to
others prejudicial to himfelf} let him be taught libera¬
lity, by finding it advantageous*, let him be. rendered
fuperior to teafing his parents or tutor with com¬
plaints, by finding his complaints unfavourably receivec.
That you may teach him to reftrain every fooliih or
irregular defire, be fure never to indulge his wifties,
fave when you find the indulgence proper for him, and
convenient for yourfelf. Cunofity,. however, is a prin¬
ciple which ought to be induftnoufty roufed m the
breaft of the child, and cheriftied there by meeting
always the readieft gratification. However you may
oppofe the boy’s inclinations in other, things, yet re-
fufe him not a proper portion of recreation : let him m
dulge in play, while he continues to play with keen-
nefs and a&ivity; but fuffer him not to loiter about
EDU
m liitleis muoience. To reftrain your child from fool- Etoom
hardy courage, point out to him the dangers to which
it expofes him : to raife him above timorous cowardice,
and infpire him with manly fortitude, accuftom him
from the earlieft period of life to an acquaintance with
fuch things as he is moft likely to be afraid of : iubject
him now and then to pain, and expofe him to danger j
but let fuch trials be judicioufty conduaed
Idlenefs or curiofity fometimes leads children to cru¬
elty in their treatment of fuch animals as are placed
within their power. Dogs, cats., birds, and butterflies,
often fuffer from their inhumanity. But when they
feem inclined to fuch cruelty, let them be carefully
watched, and let every means be ufed to awake their
hearts to generous fenfibility. Allow thern to keep
tame birds, dogs, &c. only on condition oi their ufing
them with tendernefs. Perhaps this unhappy difpofi-
tion to cruelty is occafioned, or at leaft loitered, b>
people’s laughing when they behold the impotent ef¬
forts of children to do mifchief; and often going fo xar
as even to encourage them in maltreating thole crea¬
tures which are within their reach. We entertain them,
too, with ftories of fighting and battles j and reprefent
characters diftinguiihed for atrocious acts of inhumanity
as great and illuftrious. But let fuch praaice be care¬
fully refrained from, if you wilh to mfpire your child
with generous and humane fentiments. I each him gen-
tlenefs and tendernefs, not only to brute animals, but
alfo to fervants and companions.
Curiofity is to be roufed and chenfhed in the breait
of the child : but by what means ? Anfwer his inquiries
readily : though his queftions be put in awkward lan¬
guage, let not that hinder you from attending to the
objects of them. Curiofity is natural to the human
mind ; and if you reprefs not the curiofity of the child,
he will often be moved by its impulie to the purfuit of
knowledge. Let him find his eagernefs in the purimt
of knowledge a fource of applaufe and efteem. Avoid-
the folly of thofe who fport with the credulity oi child¬
ren, by anfwering their queftions in a ludicrous or de¬
ceitful manner. . , .
You muft, however, not only hften with obliging at¬
tention to his queftions, and ftrive to gratify his curio¬
fity ; but even whenever he attempts to reaion on iuch
fubiedts as are offered to his obfervation, be careful to
encourage him : praife him if he reafons with any de- •
gree of plaufibility j even if he blunders, beware oi ri¬
diculing or laughing at him. With regard to the boy s
playthings: while you indulge him freely m innocent
diverfions, give him fuch playthings as may be necei-
fary in the amufements in which he engages, provided
thev be fuch as he cannot make himfelf j but it will be
ftill better for him to exercife his dexterity and inge¬
nuity in making them himfelf. .
After throwing out thefe things concerning the ge¬
neral principles on which education ihould be carried on,
Mr Locke next proceeds to thofe particular parts oi
knowledge in which he thinks , every young gentleman
ought to be inftrufted. In virtue, wifdom, breeding,
and learning, he comprehends all that is neceffary to
enable his pupil to adt a refpedtable part in hie.
In forming the boy to virtue, the firft thing to be done
is to inform him of the relation fubfiftmg between hu¬
man creatures and a fupreme independent Being, their
creator, preferver, and governor j and to teach him,.
. . . . F- r> u i 5J0
^ilucanen. tliat obedience and worfln'p are due to that Being, But
when you inform the child of the exiftence of an invili-
ble Being, beware of imprefling his mind with any no-
f'ons. concerning fpirits or goblins, which may render
him incapable ot bearing darknefs or folitude. In in¬
fancy our minds are, by the indiferetion of thofe about
us, generally impreffed with fuch prejudices concerning
a thouland frightful forms, ever ready to aflail or haunt
us under the fhade of night, that we become incapable
of manly fortitude during the courfe of life : the foldier
who will boldly face death in the field of battle, fliall
perhaps tremble and take to flight at the ruffling of a
few leaves, or the grunting of a hog in the dark.^ But
were the imaginations of children not crazed with wild
ftories concerning fpirits and hobgoblins, darknefs would
be no more alarming to them than light. After inform¬
ing the child of the exiftence of a Deity, and teaching
him to pray to him j next labour to imprefs his mind
with a veneration for truth, and habituate him to a ftrift
adherence to it on every occafion. Endeavour alfo to
render him gentle and good-natured.
The beft means you can ufe to teach him wifdom or
prudence in conducing himfelf in the ordinary bufinefs
/and intercourfe of life, is to teach him to defpife the
mean fliifts of cunning. The reft muft be learned by
adtual experience in life. J
I he decencies of life, comprehended under the word
Good Breeding, form no inconfiderable part of a good
education. In teaching thefe, two things are to be
attended to: . Infpire the youth with a difpofition to
pleale and oblige all with whom he is converfant 5 next,
teach him how to exprefs that difpofition in a becoming
manner. Let boifterous roughnefs, haughty contempt
of others, cenfonoufnefs, impertinent raillery, and a
fpint of contradidlion, be banifhed from his temper and
behaviour. At the fame time, beware of leading him to
regard the mere forms of intercourfe as a matter of
the higheft importance. Remember that genuine good
breeding is only an eafy and graceful way of exprefling
.good fenfe and benevolence in his converfation and de¬
portment.
Mr Locke, when he comes to give his opinion con¬
cerning thofe parts of learning which are proper to be
taught a young gentleman, and the manner in which
they ought to be communicated, advifes to initiate the
child in the art of reading, without letting him know
that he is engaged about a matter of any importance,
01 learning an accomplilhment which you are felicitous
that he ftiould acquire. Prefent it to him in the form of
an amufement, or teach him to confider it as an high
honour to be permitted-to learn his alphabet; otherwife
he will turn from it with difguft. ViTien by infinuating
arts you have allured him to apply to reading, put into
his hands fuch books as are plain, entertaining, and in-
ftrudtive. Infift not on* his reading over the Bible : in-
ifead of gaining any advantage from an indiferiminate
perufal of it at this period of life, he is likely to acquire
the moft confufed notions of religion, and an indiffer¬
ence for the facred volume during the reft of life : yet
it may be highly proper to caufe him to perufe feme
of its beautiful hiftorical paffages, and to familiarize
him with its elegant and Ample moral precepts. After
learning to read his mother tongue, the boy’s attention
ought to be next diredled to the art of writing. The
,-eafieft way to teach him that art, is to get a plate eix-
1
E D U
graved, after the model of any hand which you think Education,
moft proper for his imitation. With this plate get a —v~—*
number of copies call with red ink ; the letters of thefe
the learner may trace with his pen filled with black ink:
and he will thus in a fhort time, and without much
trouble to you or himfelf acquire a decent hand. As
drawing is ufeful on many occafions in life, if the boy
be not naturally incapable of acquiring it, he may wdth
great propriety dedicate fome part of his time and at¬
tention to that art.
When the ichoiar has attained a tolerable degree of
fkill in writing, and in reading and fpeaking his native
anguage, he muft next begin an acquaintance with o-
ther languages. Among thefe, the firft objeft of his
ftudy will naturally be the Latin. Yet let none tvafte
them time in attempting to acquire a knowledge of
Latin, but fuch as are defigped for fome of the learned
profcffions, or for the life of a gentleman without a
profeflion. To thefe laft it may be ufeful 3 to others
it is vBolly unlerviceable. But in learning the Latin
tongue,^ a much happier method than burdening and
perplexing him with rules of grammar, would be to
make him fpeak it with a tutor who wras fufficiently
mafter of it for that purpofe. Thus might he fpend
that time which is ufually occupied in acquiring this
language, in learning Ibme other neceffary branches
of education. But if you cannot conveniently have the
boy taught the language by the wray of converfation,
let the introduflory books be accompanied with an
Englilh verfion, which he may have eafy recourfe to
for the explanation of the Latin. Never perplex him
with grammatical difficulties. Reflea that, at his
age, it is impoflible to enter into the fpirit of thofe
things. Render every thing as eafy and pleafing as
poffibie : for the attention will not fail to wander, even
though you labour not to render the talk difagreeable.
Skill in grammar may be ufeful 3 but it is to thofe
whofe lives are to be dedicated to the ftudy of the dead
languages : that knowledge which the gentleman and
the man of the world may have occafion to derive from
the treafures contained in the ancient languages, may
be acquired, without a painful ftudy of profody or fyn-
tax. As the learning of any language is merely learn¬
ing words 3 if poffibie, let it be accompanied with the
acquiiition of fome real knowledge of things 3 fuch as
the nature of plants, animals, &c. their growth and pro¬
pagation. But if you cannot or will not give your boy
a private education, and are ftill refolved to fend him
to fchool, to be whipped through the ufual courfe of
Greek and Latin 3 at leaft act with fo much good
fenfe and humanity, as to infift that he be not burdened
and tormented with the compofition of Latin themes
and verfes. Neither let his memory be oppreffed with
whole pages and chapters from the claflics. Such ridi¬
culous exercifes have no tendency, whatever prejudice
may urge to the contrary, to improve him either in the
knowledge of languages or of nature.
Mr Locke feerns to wifh that the French language,
which in his days had attained to higher refinement
and a more regular analogy than any of the other mo¬
dern languages of Europe 5—he feems to with that
the French were learned along v/ith the Latin : and he
wiflies the ftudy of thefe languages to be accompanied
with the ftudy of arithmetic, geography, hiftory, and
chronology. Let theie branches of knowledge be
conamunicated
E D U [55
communicated* to the learner in one of the two lan¬
guages : and he will thus acquire the language with
greater facility. He next points out the advantages
of the branches of knowledge which he recommends
as proper to be learned together with the languages 5
but on that head he lays nothing Angular. One me¬
thod which he recommends for facilitating the fludy
of language is, to put into the youth s hands, as foon
as he has acquired a tolerable knowledge of chronolo¬
gy, fome of the molt entertaining Latin hiftorians •,
the interelling nature of the events which they relate
will not fail to command his attention, in Ipite of the
difficulty which he mult find in making out their mean¬
ing. The Bible and Tully’s Offices will be his belt
guides in the iludy of ethics. 1 he law of nature ami
nations, as well as the civil and political inftitutions ot
his country, will form to him an important objeft,
which he ought to ftudy ivith the molt careful atten¬
tion. Rhetoric and logic, though generally regarded
as objefts of great importance in a liberal education,
can neither of them contribute much with all their
rules and terms, to render him an acute realoner or an
eloquent fpeaker; and it is therefore unneceffary for
him to honour them with very particular attention.
Tully and Chillingworth will be more beneficial m
teaching him to reafon and to perfuade, than ail the
treatifes on rhetoric and logic which he can poffibly
perufe, or all the leaures on thofe arts which he can
gain opportunities to hear. In every art. and every
fcience praaice and experience are infinitely better
than rules. Natural philofophy, as contributing to
infpire the bread with warmer fentiments of devotion,
and ferving alfo to many ufeful purpofes in life, ought
to make a part in the young gentleman’s iludies.
But the humble experimental writers on that fubjea
are to be put into his hands in preference to the. lolty
builders of fyftems. As for Greek, our pupil is not
to be a profefled fcholar, but a gentleman and a man
of the world ; and therefore it does not appear necef-
fary that Greek fhould make a part in the iv Item of
his education. But in none of theie ftudies wall the
pupil ever attain any proficiency, unlefs he be.accu-
flomed to method and regularity in the profecution or
them. In languages, let him gradually alcend from
what is fimpleft to what is moil difficult: in hiifory,
let him follow the order of time ) in philofophy, that
of nature.
Dancing, as contributing to eafe and gracefulnefs
of carriage, ought to make part in our young gentle¬
man’s education. Fencing and riding being, fafuion-
abie, cannot wTell be denied him. As he is likely, in
the courfe of life, to have fome leifure hours on his
hands, and to be fometimes difpofed to adlive recrea¬
tion, let him learn fome mechanical trade, with the
exercife of which he may agreeably fill up fome of thofe
hours. If he is to pofiefs any property, let him not be
unfkilled in the management of accounts. Travel, in-
flead of being ufeful, appears more likely.to be hurt¬
ful to the underftanding and morals of the traveller,
unlefs deferred to a later period than that at which
young men are ufually fent out to complete their edu¬
cation by traverfing through foreign countries.
Here Mr Locke concludes his work with obferving,
that he does not offer it to the world as a full or com
prehenfive treatife on the fubjefl of education, but
1 ] E D u
merely as the outlines of what occurred to him as moft Eluca-tioir
proper to be obferved in breeding up a young gentle- '
man not intended for any learned profeffion or mecha¬
nical employment, but for atling a refpectable part in
life at the head of a competent hereditary fortune. . 23
In confidering the fentiments of this refpe£lable phi- Remarks,
lofopher on the fubjeft of education, we perceive, that
as he was, on the one hand, fuperior to thofe preju¬
dices which render us incapable of diftmguiffiing the
defeats or abfurdities of any cuftom or inflitution which
has long prevailed j fo, on the other hand, he was free
from that filly vanity which difpofes thofe wffio are fub-
jecl to its intluence to affebt novelty and fingularity of
fentiment on every lubjedt which they confider. Though
a member of one of the univerfities, he hefitates not
to declare himfelf againll a very laborious attention to
claffical learning j and his reafoning is, through the
whole of his treatife, rather plain and folid than fubtle
or refined.
Yet, however we refpecl the foundnefs of his under-
ffanding or the benevolence of his intentions, we can¬
not avoid obferving, that his opinions are not always
fuch as experience iuilifies. He had no doubt taken
notice of iome inilances in which the too great anxiety
of parents about the prefervation of their children’s
health was the very means of rendering their conftitu-
tion feeble and tender through the courfe of life ; and
from that circumllance might be led to propofe thofe
expedients which he mentions for preferving the health
and ilrengthening the conllitution of children. But a
little more obfervation or inquiry would have eafily con¬
vinced him, that fome of his expedients, inftead of
Ilrengthening the child’s conllitution, would in all pro¬
bability ffiorten his days.
He had perhaps feen fome of the heroes of clalfical
literature, who were familiar with Demolthenes and
Cicero, and had Homer and Virgil at their finger ends,
—he had feen fome of thofe gentlemen fo overloaded
with their cargo of Greek and Latin as to be unfit for
the ordinary bufinefs and intercourfe of life ; and fuch
inilances might tempt him to forget the advantages
which he himftlf, and a long feries of philofophers,
patriots, and llatelmen, with whofe names the annals of
our country are adorned, had derived from a regular
claffical education. But as we are afterwards to de¬
liver our own fentiments on the fubjecf, we will not
here extend our obfervations on Mr Locke to a greater
length. 2 4
An author more diflinguilhed than Mr Locke for Rouil'eau^
tendemefs of fentiment, fingularity, eloquence, and
whim, has prefented the public with a work on the fub-
jecl of education r in which, with unexampled bold-
nefs, he inveighs againll all the ellablilhed modes, as well
as reprobates whatever had been advanced by former
writers on the fubjecl 5 and at the fame time, delineates
a plan of education which he would perfuade us is in¬
finitely fuperior to thofe which he explodes. This wri¬
ter is the amiable and pathetic Rouffeau : And though
he be often vain, paradoxical, and whimfical; yet the
charm of genius and ientiment which adorns his writ¬
ings will at leall engage our attention while he unfolds
his opinions. Imprudent
He fets out with obferving, that our bufinefs in the m an age-
bringing up of children Ihould be, to lecond and to call j
forth nature 5 and that, inileadof this, we alruoll always ulfai Cy
oppofe
E D U [55
Education, opppfe her intentions and operations. As foon as the
child fees the light, he is wrapped in jfwathing bands.
His limbs are thus reftrained from that free motion
which is neceffary to their growth and vigour ; and
even the internal parts of his frame are rendered incapa¬
ble of their proper funftions. Mothers are too proud
or indolent, or too fond of gaiety and diffipation, to fub-
mit to the talk of nurling their owh children. The
poor infants are committed to fome hireling nurfe, who
not being attached to them by natural affeftion, treats
- them with negligence or inhumanity. But is that
mother capable of any delicacy of fentiment, who can
permit another to fuckle her child, and to fhare with
her, or perhaps wholly fupplant her, in the filial affec¬
tion of that child ?
Again, When parents undertake the care of their in¬
fant children, they often injure them by miftaken ten-
dernefs. They pamper them with delicate meats, cover
them with warm clothes, and anxioufly keep them at
a diftance from all that has the appearance of danger :
not attending to the economy of nature, who fubjefts
us in infancy to a long train of epidemical diifempers,
and expofes us during the fame period to innumerable
dangers j the delign of which doubtlefs is, to teach us
a prudent concern for our own fafety, and to ftrengthen
and confirm our conflitutions.
A child no fooner enters into life, than it begins to
ciy ; and during a great part of infancy continues fre¬
quently to died tears. We either attempt to foothe it
into good nature, or leek to filence it by hardier means j
and it is thus we infufe into its infant mind thofe evil
paffions which wre afterwards prefume to impute to na¬
ture.
As the mother generally difdains to nurfe her own
child, fo the father is feldom at leifure to take any fhare
in the management of his education : he is put into the
hands of a tutor. But that tutor whofe time and atten¬
tion can be purchafed for money is unworthy of the
charge. Either be yourfelf your ion’s preceptor, or
gain a friend whofe friendfhip to you fhall be his foie
26 motive to undertake the talk.
Manage- After a few preliminary obfervations to the above
ment of E- purp0rt, our author introduces his Emilius *, in whofe
milius dur- e(jucat;on he delineates that plan which he prefers,
mg infancy. preceptor whom he would affign Emilius muff be
young j and muff dedicate his attention to Emiiius alone,
from the time when his pupil enters the world till he at¬
tain the full age of manhood. Emilius, to receive the
full benefit of his preceptor’s fyilem of education, and
to afford full fcope to it, mult poffefs a genius of the
middle clafs ; no prodigy of parts, nor Angularly dull 5
he muft have been bom to affluent circumftances and
an elevated rank in life. His preceptor is invefted
with the rights, and takes upon him the obligations,
of both father and mother. Emilius is, when put
into the hands of his preceptor, a welhfhaped, vigorous,
and healthy child. The firft care of the. preceptor is
to provide him with a nurfe, who, as he is new born,
mult be newly delivered ? it is of ftill higher importance
that ffle be clean, healthy, virtuous, and of mild difpo-
fitions. While fuckling her charge, fhe fhall feed plen¬
tifully, chiefly on a vegetable diet. The child muft be
frequently bathed, in cold water if pofiible } if \ou be¬
gin with warm, however, ufe it by degrees colder and
colder, till at length he is able to bear it entirely cold.
2
2 ] E D U
He is not to be wrapped in fwaddling clothes or rol- Educalior.
lers, or bound with ftaybands } but put in good warm'
blankets, and in a roomy cradle : Let him ftretch and
move his limbs at freedom, and crawl about on hands
and knees at his pleafure. The greateft care muft now
be taken to prevent the child from contrafting any ha¬
bits whatever : Suffer him not to ufe one arm more
than another, or to eat or fleep at Hated hours. Pre¬
pare him for the enjoyment of liberty, by preferving to
him the exercife of his natural abilities, unfettered by
any artificial habits.
As foon as the child begins to diftinguifh objects, let
his education begin. Some obje&s are naturally a-
greeable, others frightful. Accuitom him to look up¬
on any objedf that may come in his way without being
affrighted. Children are at firft ignorant of local re¬
lations, and learn to diftinguifh them only by experi¬
ence j and while Emilius is yet an infant, incapable of
fpeaking or walking, he may be affifted in acquiring
the knowledge of thefe.
In his feeble helplefs condition, the child muft feel
many wants and much uneafinefs j tears are the lan¬
guage which nature has given him to make known his
diftreffes and wants. When the child cries, it would
be much more prudent and humane to examine what
he fuffers or Hands in need of, than, as is ufually done,
to rock or fing him afleep j or, when thefe means fuc-
ceed not, to threaten or ufe him brutally.
In managing children, as nature has endowed them
wdth no fuperfluous powders, we ought not to confine
them from the free ufe of thofe which they are able to
exert. It is our duty to fupply their deficiency both
of mental and bodily powers ; but while wre are ready to
adminifter on every occafion to their real wants, we muft
bewrare of gratifying their caprice or unreafonable hu¬
mours. In order to diftinguifh between their natural
and fantaftic wants, we muft ftudy the language and
figns by which they exprefs their wifhes and emotions.
Though crying be the means which nature has given
infants to enable them to procure relief er afliftance, yet
when they cry they are not always in need of either.
They often cry from obftinacy or habits of peevifhnefs.
But if, inftead of attempting to foothe them by divert¬
ing their attention to other objebls, we would on fuch
occafions entirely negledt them, they w?ould foon ceafe
to indulge in fuch fits of crying.
When children begin to fpeak, we are ufually anxi¬
ous about their language and articulation, and are every
moment correfting their blunders. But inftead of hop¬
ing to teach them purity or corre&nefs of fpeech by
fuch means as thefe, let us be careful to fpeak eafily
and corre&ly before them, and allow them to exprefs
themfelves in the beft manner they can. By fuch means
we will be much more likely to obtain our wifhes
in this matter. When they fpeak, let us not liften with
fuch folicitude as to relieve them from the neceflity of
ufing an open diftincl articulation.
When the child attains the power of expreflmg him-
felf in artificial language, he may then be confidered as
having reached the fecond period of infancy. He needs
not now to make known his wants by tears, and fhould
therefore be difeouraged from the ufe of them. Let
his tears be entirely negletted. He now begins to run
about, and you are anxious to prevent him from hurt¬
ing hirofelfj but your anxiety can only render him
peevifh
Education.
.27 .
Subjection
to authori¬
ty-
and then fuffer him to run about at
He will now and then bleed, and
but he will become bold, lively, aud
aS
Ideas of
moral obli¬
gation.
E D U
peevifh or timid. Remove him from
ing danger,
his pleai’ure
liurt himfelf
cheerful.
In regulating the conduft of your child, let him
know that he is dependant j but require not of him an
implicit fubmiflion to your will. Let his unreafonable
defires be oppoi'ed only by his natural inability to gra¬
tify them, or by the inconveniences attending the gra¬
tification. When he afhs what is necelTary or reaion-
able, let him inftantly obtain it j when he afks what is
unreafonable or improper, lend a deaf ear to all his
entreaties and demands. Beware of teaching him to
ellabliih his authority over you by means of the forms
of politenefs. A. child wall fcarce take the trouble to
addrefs you with If you pleafe* unlefs he has been made
to regard thefe as a let of magic fyllables, by the ule
of which he may 1 abject every perfon to his will. His
If you pleafe then means / pleafe } pray, with him, lianas
for, do. Though you put in his mouth the words of
humility, his tone and air are thofe of authority that
'ivill be obeyed. _
Sacrifice not tlie prefent happmefs of youi ciiild for
the fake of any diftant advantage.
Be not too anxious to guard hiin againft natural
evil. The liberty which he enjoys while he is now and
then permitted to expofe himfelf to blows, or cold, or
wetnefs, is more than a fufficient compenlation for all
that he thus fullers.
Seek not to imprefs him with iaeas of dutij or obliga¬
tion. Till children reach the years of difcretion, they
are incapable of any notions of the dillindlions ot mo¬
rality. Avoid therefore even the ule of the terms_
by which they are exprelfed in their hearing. While
they continue to be affefled only by fenfible objects,
feek not to extend their ideas beyond the fphere of
lenfation. Try all the powers of language, ufe the
plainell and moll familiar methods you can contrive j
you lhall Hill be unable to give the boy at this age any
juft ideas of the diftinclion between right and_ wrong.
He mav readily conceive, that for one fet of actions
you will punifh him, and that oy another he will ob¬
tain your approbation but farther than this his ideas
of right and wrong, of virtue and vice, cannot yet be
carried.
The powers of the human mind are gradually un¬
folded. 1 At firft, the infant is capable only of percep¬
tion; by and by, his inftin&s and paflions begin to
exert their force -, at length, as he advances towards
manhood, realon begins to a£l, and he becomes able
to feel the beauty of virtue and the deformity of
vice.
But though you feek not to regulate his condufl
by notions oi duty, yet let him feel the yoke of necei-
fity. Let him know, that as he is weaker than you,
he mull not, therefore, expect that you Ihould be fub-
je6t to his will j and that, as he has neither Ikill nor
ftrength to control the laws of nature, and make every
obje£l around him bend to his pleafure, he cannot hope
to obtain the gratification of all his wiih.es. I hus you
teach him virtue before he knows what virtue is 5 and
call forth#,his reafon without mitleading or perverting
it. Let him feel his impotence •, but forbid him not
to think, that if he had power there would be no rea-
Vol. VII. Part II.
[ 553 1 . £ D U
any very alarm- fon why he might not at pleafure even turn the world Elueation.
upfide down. '
Hitherto you have given your pupil no verbal in-
ftrudlions, nor muft you yet attempt to inftruct him by
any other means than experience j let all his knowledge
be literally of his own acquifition.
Let not the parent who has obferved the condufl of
children brought up in the ufual way be afraid that, if
his child Ihould be treated like our pupil, he would be¬
come ftupid and vicious. Nature fends not human be¬
ings into the world with a predifpofition to vice : we
fovv the feeds of it in the infant heart ; and by our ab-
furd modes of treatment, we alio enfeeble and pervert
the powers of the underftanding.
But from the hour of his birth till he attain the age
of twelve, the education of Emilius lhall be purely ne -
gative. Could we but bring him up healthy and ro-
buft, and entirely ignorant, till that period, the eyes of
his underftanding would then be open to every leflbn ;
free from the influence of habit and prejudice, his paf-
fions would not then oppofe us ; and we might render
him the wifeft and moll virtuous of men. If we can
but lofe time, if we can but advance without receiving
any impreffions whatever, our gains are unfpeakable.
Nature gives the powers of every mind lome particular
diredlion : but that particular bias, impreffed by the
hand of nature, cannot be diftinguilhed before the pe¬
riod we have mentioned \ and if you counteract nature,
inftead of feconding her views, the confequences cannot
but be highly unfavourable both to the heart and the
underftanding of your pupil.
Perhaps, in the midft of fociety, it may be difficult
to bring up our pupil without giving him fome idea of
the relations between man and man, and of the mora¬
lity of human actions. Let that, however, be deferred
as long as poffible.
Were Emilius to witnefs a fcene of anger, and to alk
the caufe of the appearances which he beheld, he Ihould
be told that the perfons were aftebled with a fit of lud-
den illnefs. We might thus perhaps prevent the unhap¬
py effects of fuch an example.
The firft moral notions which fhould be communi¬
cated to the child are thofe of property. To commu¬
nicate the ideas of property to our pupil, we will di¬
rect him to take poffeffion of fomething ; for inftance,
of a piece of ground belonging to fome other pexfon,
and in a ftate of cultivation. Let him cultivate this
fpot of ground anew, fow it with feeds, and look ea¬
gerly forward to the time of harveft in the hopes of
reaping the fruit of his labours. In the mean time, let
the proprietor of the ground take notice of what is
done, deftroy your pupil’s riling crop, and complain of
the injuftice done him. While the boy laments his
lofs and the difappointment of his hopes, in all the
bitternefs of grief, let the proprietor of the ground
ftill infill on the injury done him, and complain of
what he fullers by the purpofe for which he himfelf
had cultivated and fown the ground being frullrated.
Our pupil, now fenfible of the realbnablenefs of the
other’s claims, will defift from his lamentations, and
only beg to have fome other fpot affigned him which
he may cultivate at his plealure without offending any
perfon. This he will juilly confider as his own pro¬
perty, to the produ£tions 0! which raifed by his own
labour he has an exclufive right, and in the occupying
4 A of
ECU [
Education of winch none ought to moleft him. In fome fuch
manner as this may the nature of property, the idea of
which eafily refers in the inftance to the firft occupier,
and afterwards the exchange of property, be explained
to him.
Another inftance of the manner in which the pupil
is now to be managed may not be improper in this
place. He is poffibly fo rude and boifterous as to fpoil
or break whatever is within his reach. Be not angry
with him, however : if he break the utenfils which he
has conflant need of, be in no hafte to fupply him
with others in their room j let other things be re¬
moved out of his way : if he break the windows of
his apartment, let him be expofed night and day to
the cold ; complain not of the inconvenience yourfelf,
but order matters fo that he may feel it. After fome
time, let them be mended up 5 and if he break them a-
gain, change your method. Tell him calmly, “ Thefe
windows are mine; I took care to have them put
there 5 and I will prevent their being again broken,
by confining you in a dark room.” Let all his en¬
deavours to avoid this prove ineffectual. Let him be
aCtually confined, and be liberated only on propofing
and agreeing to the condition of breaking no more
windows. When he propofes this condition, be ready
to liften to him ; obferve that it is well thought on,
and that it is a pity he did not think of it fooner. Con-
fider this engagement between you as facred j treat
him as before, and you cannot fail to attain the end in
view.
The'moral world now opens to us : But no fooner
are we able to diltinguifh between right and wrong,
than we become defirous to conceal thofe initances in
which we aCt wrong. Lying is therefore a vice of
which your pupil is now apt to be guilty : you cannot
always prevent, but you can punifh} but let the punifh-
ments which you infliCt appear to the child only the
natural confequences of his conduCt. If he is in any
inftance convicted of a lie, let his affertions no longer
gain credit. By this means, fooner than by precepts,
or any other fpecies of punifhment, will you be able to
reclaim him from the habit of lying.
The methods generally taken to render children
virtuous are prepofterous and foolifh. To render them
generous and charitable, we give them money, and bid
them beftow it in alms, while wTe ourfelves give nothing 5
but the parent or mafter, and not the child, fhould beftow
the alms. Example might produce the wifhed-for effeCt.
Befides, children are ftrangers to the value of money.
A gingerbread cake is more to them than a hundred
guineas. Though you teach them to give away
money, till you perfuade them to part readily with
thofe things which they value moft, you do not infpire
them with generofity. Would you make them liberal
by fhowing them that the moft liberal is always beft
provided for ? this is to teach covetoufnefs, not libera¬
lity. Example is the only means by which you can,
at this period, hope to teach your pupil any of the
virtues.
The only leffon of morality that can with any pro¬
priety be inculcated on children, is to injure no per-
fon. Even the pofitive precept of doing good, muff
be confidered as fubordinate to this negative one of
doing no harm. The moft virtuous and the molt ex-
554-1 E D U
alted of characters, is the man who does the leaf! harm Education-,
to his fellow creatures. '"“’’“■v"'
In a public education, it xvill be neceffary to attempt
the communication of moral inltruction at an earlier
period than in a private one. In a private education,
it w-ill always be beft to allow the moral powers of
children to ripen as much as poffible before you en¬
deavour to inform and direCt them by precepts.
There is an inequality among geniufes j and fond
mothers and fathers may be dilpofed to plead for ex¬
ceptions in favour of fuch of their children as they
view with a partial eye. “ This boy’s mind is more
capacious, his powers are riper, than thofe of others.”
But however great the feeming difparity of geniufes
may be, it is at bottom but inconfiderable. Let the
age of children be therefore regarded as a common
meafure by which their treatment is to be regulated.
However quick and tenacious the memories of chil¬
dren may feem, they can derive little advantage from
the exertions of memory till fuch time as judgment
begins to aft. All the knowledge that they acquire
in the courfe of the ufual fyftem of education, is
merely the knowledge of words. The languages,
geography, chronology, in fhort all that they are
taught, and called to difplay fo oftentatioufly at this
other purpofe than to fill their
period of life, ferve no
minds with words.
Hillory is efteemed
the hands of children.
29
a proper thing to be put intoHiftory,
But except you with to con- far
fine their attention to the external and phyfical aftions, ^roPc^ f°
it is almoft nothing they can acquire by the perufalthe^ambof
of it. And if diverted of the moral diftinftions of boys,
aftions, of the workings of the paflions, and the com¬
plication of interefts, what is there to render hiftory
entertaining ? We may indeed eafily teach them to re¬
peat the words kings, emperors, wars, conquejls, revo¬
lutions, laws : but of the things which you ufe thefe
words to denote, you will find they are hitherto inca¬
pable of forming any clear ideas.
But the mere knowledge of words is not fcience $
make your pupil acquainted with things, and he will not
fail to acquire their names. Emilius muft never be fet
to get any compofition by heart, not even fables : be
careful to place before him thofe fcenes and objefts, the
images of which it may be ufeful for him to have im-
preffed on his memory j but by no other means feek to
aflirt him to improve that faculty.
Emilius ftiall not even learn to read till he attain the
age of twelve : for, before that period, it can be of no
benefit to him ; and the labour would only make him
unhappy during that period of life which is naturally
the golden part of our days. But -when he has attain¬
ed the proper age, matters fliall be fo ordered, that he
lhall find his ignorance of letters an inconvenience. A
card {hall be fent him, which being unable to read, he
will apply to fome of thofe about him. They may be
unwilling to oblige him, or otherwife engaged, if, at
length, it is read to him, that may be when it is now
too late to take advantage of fome agreeable invitation
which it contained. This may be two or three times
repeated. At length he becomes eager to learn to read j
and accomplilhes that almoft without afliftance.
The principle on which we proceed, is to leave the
pupil almoft ■wholly under his own direftion, feemingly
at
E D U [ 555
Education, at leafi *, to lead him to acquire new accomplifhments,
1 u" *" folely from the deiire of increafmg his powers, and
extending his influence 5 and humbly to follow nature,
not to force her.
As we are defirous of cultivating his underftanding,
the means which we employ for that purpofe is, to cul¬
tivate thofe abilities on which it depends ; he is always
aftive and in motion. Let us firft make him a man in
point of health and vigour, and he will foon become a
man in underftanding.
By our conftant attention to the welfare of children,
we render it unneceffkry for them to attend to it them-
felves. What occafion has your fon or pupil to obferve
whether the afpect of the Iky threaten rain, wdien he
knows that you will take care to have him Iheltered
from a (hower ? or to regulate the length of his excur-
fions, when he is fure that you wall not fuffer him to
lofe his dinner ?
While matters are fo ordered that Emilius thinks him-
felf fubjedt only to his own will, though all his motions
are regulated according to your pleafure } inftead of
becoming fantaftic and capricious, he infenfibly ac¬
quires the habit of keeping utility in view in all his
actions.
The firft objefts which engage the attention of chil¬
dren are the appearances of the material wrorld around
them : our firft ftudy is a kind of experimental philo-
fophy 5 our inftruments and inftruftors are our hands,
our feet, and our eyes. By exercifing thefe bodily
organs, the boy wrill acquire more real knowledge
even in the period of childhood, than if he Ihould de¬
dicate nine-tenths of his time to books, from the age
of fix to fixty. All who have examined, with any fa-
gacity, the charafters, circumftances, and manners of
the ancients, have agreed in attributing to their gym-
naftic exercifes that fuperior ftrength of body and
mind which renders them objefts of admiration to the
moderns.
Our pupil’s clothes cannot be too light and eafy. If
tight and clofe, they fetter and confine his joints and
limbs, and likewife obftruft the circulation of the
blood j if accuftomed to warm clothing, he will foon
become incapable of bearing cold.
In every thing let him be habituated to what is
plain and hardy. Let his bed be coarfe and hard, his
clothes plain, his fare Ample. Infants muft be freely
indulged in fleep : but as Emilius is now advanced be¬
yond infancy, he muft be accuftomed at times to go
to bed late and get up early, to be fometimes haftily
WTaked from fleep ; and thus to prepare himfelf for what
he may afterwards have occafion to fubmit to in the
courfe of life.
As this period is in a particular manner that of ex-
ercife, and Emilius is encouraged to take as much
exercife as he choofes : wre muft endeavour to prompt,
but without feeming to direct him to fuch as are moft
proper. Swimming, though not generally attended to,
is yet one of the firft which a boy ought to learn. It
may, on many occafions in life, be of the greateft ad¬
vantage, by enabling us to fave our own life or the
life of others. Emilius fhall be taught to fwim •, he
(hall be taught whatever can really enlarge the fphere
of his powTer : “ could I teach him to fly in the air, I
would make him an eagle 5 if to bear the fire, a fala-
niander,”
3°
Expofure
and exer-
■cife.
] E D U
To exercife the fenfes is not merely to make ufe of Education,
them j it is to learn to judge by them. Call not your “-y—^
pupil to exert all his ftrength on every occafion 5 but
let him learn to judge of the truth of the information
which he receives from one fenfe, by having recourle
to the evidence of another.
It is not impoffible to improve the fenfes to a higher
degree of perfection than that which they ufually at¬
tain. Blind men general poffels the fenfe of touch
in a more exquifite degree, than we who have alfo
eyes to guide and inform us. But they acquire this
fuperior delicacy and acutenefs of fenfation, only by
their finding it neceiTary to have more frequent re-
courfe to the information of that fenfe. Here is then
a wide field for improvement and agreeable exercife to
our pupil.
What a variety of ufeful diverfions might he be led Darknefs
to entertain himfelf with in the courfe of the night, and ghofts.
The hours of darknefs are generally hours of terror,
not only men, but alfo to the brute animals. Even
reafon, knowledge, and courage, are not always fuffi-
cient to render us fuperior to the terror which darknefs
infpires.
This timidity is ufually attributed to the tales of
ghofts and goblins with which we are frightened in
infancy. But it originates from another caufe : our
ignorance of what is pafiing around us, and our ina¬
bility to diftinguilh objefts during that period of
darknefs. The paflion of fear was implanted by nature
in the human breaft, in order that it might ferve to
put us on our guard againft danger. But in confe-
quence of our being fubjeCt to the influence of that
paflion, when we are ignorant of what furrounds us,
imagination calls up dangers on all hands. And fuch
is the caufe from which cur terror in darknefs naturally
arifes.
But the only way to free our pupil from this tyran¬
ny of imagination, is to oppofe to it the power of ha¬
bit. A bricklayer or tyler is never giddy on looking
down from the roofs of houfes. Neither will our pupil
be alarmed by the terrors of darknefs, if he be accu¬
ftomed to go frequently abroad under night. It is eafy
to contrive a number of little amufements, the agree-
ablenefs of which may, for a time, overcome our pupil’s
averfion for darknefs j and thus may a habit be at length
impreffed.
Let us give yet another inftance of the means by
which children may be led to do wdiat we wilh, with¬
out our impofing any reftraint on their will. Sup-
pofe Emilius is lazy and inaftive, and we wifli to make
him learn to run. When walking out with the young
fluggard after dinner, I would fometimes put a couple
of his favourite cakes in my pocket j of thefe each of
us Ihould eat one in the courfe of our walk. After
fome time I would flrow him I had put a third cake
in my pocket. This he would not fail to alk after
finftiing his own : no fays I, I can eat it myfelf, or w’e
will divide it j—or ftay, wre had better let thefe two
little boys there run a race for it. Accordingly I pro-
pofe the race to the boys j wdio readily accept the con¬
ditions, and one of them carries off the prize. After
feeing this feveral times repeated, Emilius begins to
think himfelf qualified to obtain the third cake as ■well
as any of the little boys, and to look upon running as
an accompliftiment of fome confequence. He feeks an
4 A 2 opportunity
E D U t 5
Education opportunity of being permitted to enter the lifts. He
—v ^ runs j and after being two or three times outftripped, is
at length fuccefsful, and in a fliort time attains an un-
31 doubted fuperiority.
Drawing. children naturally imitate almoft whatever they
behold, they are often difpofed to attempt drawing.
In this our pupil might be obliged, not merely for the
fake of the art, but to give' him a fteady hand and a
good eye. But he fhould draw from nature, not from
other drawings or from prints. W ere he to draw the
likenefs of a horfe, he fhould look at the animal : if to
attempt a reprefentation of a houfe, he fhould view the
houfe itfelf. In this method he will, no doubt, fcratch
for a long time without producing any likenefs : but
he wall acquire what we propofed as the ends of his at¬
tempting to draw •, namely, fteadinefs of hand and
juftnefs of fight, by this method, fooner than by any
33 other.
Geometry. Geometry, when taught in the ufual way, is cer¬
tainly above the capacity of children *, they cannot go
along with us in our reafonings : Yet they are not to¬
tally incapable of acquiring even this difficult fcience 5
if, when they are profecuting their amufements, you
lead them infenfibly to obferve the properties of the
circle, the triangle, and the fquare, and place them
now and then in circumftances when they may have
occafion to apply their knowledge of thefe to real ufes
in life.
A child has been taught the various relations be¬
tween the outlines, furfaces, and contents of bodies, by
having cakes let before him, cut into all manner of re¬
gular iolids 5 by winch means he was led to mafler the
ivhole fcience of Archimedes, by ftudying which form
contained the greateft quantity.
There is a period between infancy and the age of
puberty, at which the growth and improvement of our
faculties exceed the increafe of our defires. About I 2
or 13, when the appetite for the fex has not yet begun
to make itfelf felt, wdien unnatural w-ants are yet un-
knowrt, no falfe appetites yet acquired } at that pe¬
riod, though weak as a man, as a child the youth is
ftrong.
This interval, when the individual is able to effeft
more than is neceffary for the gratification of his
wfilhes, contains the moft precious moments of his life,
which ought to be anxioufly filled up in an ufeful
manner. This is the beft time for employment, for
inftruftion, for ftudy.
Now, let us begin to confider what is ufeful; for,
hitherto, we have only inquired what was neceflary.
In entering on our ftudies, wre will make no account of
any but fuch as inftincl direcls us to purfue : thofe
which the pedant and the pretended philofopher are
impelled to purfue folely from the defire of attraft-
ing the admiration of mankind, are unworthy of our
notice.
The earth which we inhabit, and the fun by whofe
beams we are enlightened, are the firft objects which
claim our attention. We will therefore direft the at¬
tention of our pupil to the phenomena of nature. We
•wall lead him to the knowledge of geography, not by
maps, fpheres, and globes : we wall lead Emilius out
on fome beautiful evening to behold the fetting fun.
Here we take particular notice of fuch objefts as
mark the place of his going down. Next morning
56
J E D U
we vifit the fpot to contemplate the rifing of the Education,
glorious luminary. After contemplating for feme' v —'
time the fucceffive appearances which the feene before
us affumes, and making Emilius obferve the hills and
the other furrounding objetls, I Hand filent a few mo¬
ments, affedting to be occupied in deep meditation;
At laft I addrefs him thus : “ I am thinking, that
when the fun fet laft night, it went down yonder •,
whereas this morning you fee he is rifen on the oppo-
fite of the plain here before us. What can be the
meaning of this I fay nothing more at this time,
but rather endeavour to dire£t his attention to other
objects.
This is our firft leffon on cofmography.
Our laft obfervation was made about Midfummer;
wre will next view the rifing fun on fome fine morn¬
ing in the middle of winter. This fecond obfervation
fliall be made on the very fame fpot which we chofe
for the former. When Emilius and I perceive the
fun now emerging above the horizon, wre are itruck
at the change of the place of his rifing. By fuch
leflbns as thele may the pupil be gradually taught
a real, not a feeming, acquaintance with the relative
motions of the fan and the planets and with geogra¬
phy.
During the firft period of childhood, the great ob-
jeef of our fyftem of education was to fpend our time
as idly as poflible, in order that we might avoid cm- ^
ploying it to an ill purpofe : but our view’s are now ohjedts c!n-
changed with our pupil’s progrefs in life ; and wepmv the fe-
have fcarce enough of time for the accomplifhment of cond period
our neceflary purfuits. We therefore proceed as .quick-
ly as poftible in making ourfelves acquainted with the
nature of the bodies around us, and the laws by which
their motions and appearances are regulated. W e
keep to this ftudy at prefent, as being neceffary for
the moft important purpofes in life, and as being the
moft fuitable to the prefent ftate of our pupil’s powers.
We ftill begin with the moft common and obvious
phenomena of nature, regarding them as mere .fads ;
and, advancing from thefe, we come to generalize by
degrees.
As foon as we are fo far advanced as to be able to
give our pupil an idea of wdiat is meant by the w ord
ufeful, we have attained a confiderable influence over
his future condud. On every, occafion after this, a
frequent queftion between us will be, Of what uie. is
this ? This fhall be the inftrument by means of which
I fhall now be able to render him abfolutely fubmiflive
to my willies. However, I wall allow him to make ufe
of it in his turn, and wall be careful not to^ require of
him to do or learn any thing the utility of which he
cannot comprehend.
Books only teach people to talk about what they
do not underftand. Emilius fhall have as little re-
courfe as poflible to books for inftrudion. ^ et if we
can find a book in which all the natural wants of man
are difplayed in a manner fuitable to the underftand-
ing of a child, and in which the means of latisfymg
thofe wants are gradually difplayed with the fame
cafe and fimplicity ; fuch a book will be worthy of
his moft attentive ftudy. There is fuch a book to be
found ; but it is neither Ariftotle, nor Pliny, nor ^
Buffon ; it is Robinfon Crufoe. Emilius fhall have Robmion
the adventures of Robinfon put into his hands: he Crufoe.
fhall
.Education.
E D U [ 557 1 ,,, , E, Df Uh-
fhall imitate his example even affed his drefs ; and, vate the land winch he mhents from h.s
_ , . _  : without the
mall imitaie ms > ~ . r • i ' , '
like Robinfon, learn to provide lor himfelf without the
aid of others. „ ^ a • * i
Another employment of Emihus at this period
ihall be, to vilit the fliops of various artilans j and
when he enters a Ihop, he Ihall never come out with¬
out lending a hand to the work, and underftandmg
the nature and the reafon of what he fees going for-
Still, however, we are careful to afford not a hint
concerning thofe focial relations the nature of which
he is not yet able to comprehend.
The value and importance of the various arts are
ordinarily eilimated, not according to their real uti¬
lity, but by a very injudicious mode of eftimation :
Thoie which contribute in a particular manner to the
gratification of the fantaftic willies of the rich, are pre¬
ferred to thofe which fupply the indifpenfable neceffa-
ries of life. But Emilius ihall be taught to view them
in a different light. Robinfon Crufoe fhall teach him
to value the flock of a petty ironmonger above that
of the mofl magnificent toy-fhop m Europe. Let us
eftablifh it as a maxim, that we are to lead our pupil
to form juil notions of things for himfelf, not to
diftate to him ours. He will eflimate the works both
of nature and art by their relation to his own conve¬
nience ; and will therefore regard them as more pre¬
cious than gold—-a fhoemaker or a mafon, as a man
of more importance than the moll celebrated jeweller
in Europe. . . .
The intercourfe of the arts confifts in tae reciprocal
exchange of induflry j that of commerce, in the ex-'
change of commodities j and that of money, in tne ex¬
change of bills and cafli. To make our pupil compre-
hend the nature of thefe, we have now only to generalize
and extend to a variety of examples thole ideas ct the
nature of property, and of the exchange of property,
which we formerly communicated to him. I he nature
of money, as bearing only a conventional valve, which
it derives from the agreement of men to ufe it as a ngn
for facilitating commerce,, may be now explained to E-
milius, and will be ealily comprehended by bim. ^ But
go no farther : feek not yet to explain to the child in
what manner money has given rife to the numerous
chimeras of prejudice and caprice •, nor how countries
which abound mofl in gold and filver, come to be tne
mofl deflitute of real wealth. .
Still our views are direfled to bring up our pupil m
fiuch a manner that he may be qualified to occupy any
place in the order of focicty into which even the caprice
of fortune can throw him. Let us make him a man j
not a flave, a lord, or a monarch. How much fuperior
the character of a king of Syracufe turned fchoolmafter
at Corinth, of a king of Macedon become a notary^ at
Rome, to an unhappy Tarquin incapable of fupporting
himfelf in a date of independence when expelled from
his kingdom !
Whatever be our fituation in the world, we can con¬
tribute nothing but our perfonal abilities to fociety.
0 To exert them is therefore the indilpenfaole duty of
young man every one enjoys the advantages of a focial date ;
fph„eatoefverand to cultivate them in our pupil to the bed purpofe,
life, learn a ought to be the great aim of every courfe of education.
Wade. Emilius has already made himfelf familiar with all the
labours of hufbandry; I can therefore bid him culti-
3*
The pro¬
priety of
making
father. But Education.
if it fhould be lod, what fliall be hisrefource ? He fhall'
learn a trade, that he may be provided agamd fuch an
accident. And he fhall not be a politician, a painter.
a mufician, or an archited *, to gain employment tor
his talents in any of thefe arts, would cod him no leis
trouble than to regain his lod edate. He fhall learn
fome fimple mechanical art: he will then need only to
dep into the fird drop he fees open, to perform his
day’s labour, and receives his wages. .
It may be here proper to take notice ot a miltake
into which people generally fall in determining the trade
or profedion in which they are to place their children..
Some accident difpofes the child to declare himfelf for
a particular employment : the( parent regards that as
the employment to which his talents are fitted by the
defign of nature ; and permits him to embrace it with¬
out inquiring whether another would have been mom
datable or advantageous. But becaufe I am plea.ed
with my occupation, I am not on that account necef-
farily qualified for it. Inclinations do not confer abi¬
lities. It requires more careful and accurate obferva-
tion than is generally imagined,^ to didtnguifh the par¬
ticular tade and genius with which nature has endow eo
the mind of a child. We view him carelefsly, and of
confequence we are apt to midake cafual inclination
for original difpofition.
But Emilius needs not now to hefitate about the oc¬
cupation which he is to choofe. It is to be fome me¬
chanical employment. All the didinaion we have now
to make is, to prefer one that is cleanly and not likely
to be injurious to his health. We fhall make choice
of that of a joiner. We cannot dedicate all our time
to the trade •, but at lead for two days in the week we
will employ ourfelves in learning our trade.^ \\ e will
have no workfhop ereaed for our convenience, nor
will we have a joiner to wait on us in order to give us
the neceffary inflruaiotts : But for the two days in eve¬
ry week which we dedicate to the purpole of learning
a trade, we will go to our mader’s workfhop j ue ^
will rife before him in the morning •, work according
to his orders } eat at his table } and, after doing our¬
felves the honour of dipping with his family, return
to our own hard mattreffes at night. We fhall be
treated only according to the merit of our performan¬
ces. Our mader fhall find fault with our work when
clumfily or negligently done, and be pleafed with it
only when tvell executed. _ 37
While my pupil has been accudomed to bodily ex- New ideas
ercife and manual labour, his education has been hi- fuggefted
therto conduaed in fuch a manner as to give him in- b° £™apu_s
fenfibly a tafle for redeaion and meditation.^ Before piication to
he has been long a workman, therefore, he will begin a trade,
to become more fenfible of that inequality of ranks
which takes place in the order of fociety. He will
therefore take notice of his own dependence, and of
my apparent wealth, and will be defirous to know why
I contribute not my perfonal exertions to fociety. I put
off the quedion w ith telling him, that I bedow my fu-
perfluous wealth on him and the poor \ and will take
to make a bench or table every w7eek, that I may not
be quite ufelefs to the public.
And now, when about to enter the mod critical
period of life, when jud on the brink of that age at
which the heart and blood begin to feel the impulfe of
3 8
Progrefs
that Emi-
lius has
made be-
for the
age of pu¬
berty.
Ed E D U [ 558
a new appetite, what 'progrefs lias our pupil made >
what knowledge has he acquired ? All his fcience is
merely phyfical. Hitherto he has fcarce acquired any
ineas of moral relations ; but the effential relations be¬
tween men and things he has attentively ftudied. He
knows the general qualities of certain bodies j but upon
thoxe qualities he has not attempted to reafon. He
has an idea of abftraft fpace by means of geometrical
gures J of abllract quantity, by means of algebraical
hgns. He has no defire to find out the efi'ence of
things ; their relations alone interefi: him. He values
nothing external but from its relation to himfelf. The
general confent of mankind, or the caprice of cuftom,
have not yet given any thing a value in his eyes: utility
alone is his meafure of eftimation. He is laborious,
temperate, patient, refolute, and bold. His imagi¬
nation never exaggerates danger. He fcarce knows
as yet what death is j but fliould it approach him, he
is prepared to fubmit to neceffity. He is virtuous in
every thing relative merely to himfelf. He is prepared
to become a virtuous member of fociety as foon as he
xhall be made acquainted with the nature of his focial
relations. He is free from vice and error as far as is pof-
hble for human nature. He confiders himfelf as uncon-
nected with others ; requires nothing from any nerfon,
and thinks none has a right to require any thing of
him. Sure a youth arrived thus at his fifteenth ‘year
New La- th£ peri°d of his infancy,
fares to be . ?Utf °Ur PUpil haS reacllecl the moft critical pe-
adopted in ”od of life. He now feels the influence of the paffion
his educa- for the lex ; and as foon as we become fubjedt to the
1
E D U
pamons, his employment, his pleafures. Let all our care Education,
be diredted to nourifh his fenfibility without inflaming
us defires. As his moral powers now begin to unfold
them.elves 4, in cultivating them let us proceed not by
way of leefure, or by directing his attention to books,
->ut ftnl by leading, him to acquire experience. At
ength the period will arrive for communicating to him
fome religious mflrudion. When he knows the na¬
ture of his relations to fociety, he may be informed of
his i elation to, and dependence upon, a Deity.
. ^rT1le creed of the Savoyard curate, containing
thole fentiments concerning religious matters which
Kou lean feems to propofe as the moft proper to be
inculcated on his pupil, comes next in the order of the
work j but it does not appear to be fo clofely con-
nected with the fubjedl of education as to render
^uPrrPer- f°r US ^ve a yiew of ^ in this place,
i-he lentiments which he there advances, the reafon-
nigs which he urges, are evidently hoiiile to reveal¬
ed religion j and the power of his eloquence has
adorned flight and fuperficial arguments with fuch a
charm, that even the fterneft believer, if not abfo-
lutely defhtute of taife and feeling, mull; read them
with delight.]
And now, notwithftanding all my arts, I can no
longer keep back that moment which I have endeavour¬
ed to defer to.as late a period as poffible. As foon as I
perceive that it has certainly arrived, I no longer treat
Emihus as my pupil or difciple, but as my friend.
His afleftions are now expanded beyond himfelf j his
moral powers have.begun to exert themfelves, and have
tion at that influence of that naff,on w™ T JT • , , - PTers nave be§un to exert themfelves, and have
age. ;ZTtZ P? ’ -n f6"0 lon^r unfoclal be' received fome cultivation j he alfo is become capable
.g-. he uant of a miflrels foon produces the tvant of relirrtnuo  i • /i. n i • P -
. ^Pne want a miftrefs foon produces the want
of a mend.
As hitherto we have been careful not to force or
anticipate nature, fo even now our attention muff be
diredfed to divert the impulfes of that dangerous appe¬
tite which now begins to make itfelf felt. To confine
the growing paflions within proper limits, let it be our
care to defer as long as poflible the time at which they
begin to difplay themfelves. For this purpofe, let us
cautioufiy guard our words and aftions in the prefence
of our pupil. Let us be careful to give him no prema¬
ture mitruftions.
To excite and cherifh that fenfibility of mind which
now firft begins to fhow itfelf, to extend the care of
the youth beyond himfelf, and to interefi him in the
welfare. of his fellow creatures, let us be careful to put
fuch objeds in his way as have a tendency to call forth
and refine the feelings. It is not poffible for the hu¬
man heart to fympathize with thofe who are happier
than ourfelves : our fympathy is moved only by the
fight of mifery. We pity in others only thofe diftref-
fes to which we ourfelves are liable ; and our pity for
the misfortunes of others is meafured, not by the quan¬
tity of the evil, but by the fuppofed fenfibility of the
fufTerer. Let thefe obfervations ferve to direft us in
what manner we are to form the minds of children to
humanity and compaflion.
In profecution of our defign, to retard rather than ac¬
celerate the growth of the paffions, let us, when that cri¬
tical period which we have fo much feared comes on, fe-
clude him as much as poflible from the intercourfe of fo¬
ciety, where fo many obje&s appear to inflame the ap¬
petites, Let us be circumfpedl in the choice of his com-
3
r-,*. r •     — vapauic
ot religious fentiments, and inflruaed in the nature of
his relation to a fupreme Being. Befides, it is now
requifite, if we confider the period to which nature
has condufted him, that he fhould no longer be treat¬
ed as a fimple child. Hitherto ignorance has been his
guardian, but now he mull be reflrained by his own
good fenfe.
Now is. the time for me to give him in my accounts j
to fhow him in what manner his time and mine have
been employed ; to . acquaint him with his llation and
mine, with our obligations to each other, his moral
relations, the engagements he has entered into with
regard to others, the degree of improvement which he
has attained, the difficulties he will hereafter meet
with, and the means by which he may furmount them ;
in^a word, to point out to him his critical fituation,
and the. new perils which furround him ; and to lay
before him all the folid reafons which fhould engage
him to watch with the utmofl attention over his con-
du£l, and to be Cautious of indulging his youthful de¬
fires.
Books, folitude, idlenefs, a fedentary and effemi- Means’em
nate life, the company of women and young people, ployed to
are what he mull carefully avoid at this age. He has preferve
learned a trade, he is not unfkilled in agriculture •the PuritT
thefe may. be means, but not our only means, for pre!of h!s ma!l-
ferving him from the impulfe of fenfual defire. He is nerS'
now too familiar with thefe ; he can exercife them
without taking the trouble to refledl; and while his
hands are bufy, his head may be engaged about fome-
thing quite different from that in which he is employ¬
ed. He mufl have fome new exercife which may at
once fix his attention and caufe him to exert his bodily
powers.
E D U [ 559 ] E D U
Education, powers. We can find none more iuitable for this pur-
' v   pofe than hunting. Now, therefore, Emilius {hall
eagerly join in the chafe } and though I do not wilh
him to acquire that cruelty of difpofition and ferocity
of temper which ufually diftinguiih thofe who dedi¬
cate their lives to that barbarous diverfion, yet at pre-
fent it may have the happieft effecls in fufpending the
influence of the moft dangerous of paflions.
When I have now conducted my pupil fo far j have
informed him of what I have done for him, and of the
difficulty of his fituation •, and have refigned my au¬
thority into his hands •, he is fo fenfible of the dangers
to which he is expofed, and of the tender folicitude
with which I have wTatched over him, that he ftill
wilhes to continue under my direction. With fome
feigned difficulty I again relume the reins. My au¬
thority is now eltablifhed. I may command obedience j
but I endeavour to guard againlt the neceflity of ufing
it in this manner.
To preferve him from indulging in licentious plea-
fures, I let him know that nature has defigned us for
living in a ftate of marriage, and invite him to go in
fearch of a female companion. I will defcribe to him
the woman whom he is to confider as wrorthy of his at,
tachment in the moft flattering colours. 1 will array
her in fuch charms, that his heart fliall be hers before
he has once feen her. I will even name her : her name
{hall be Sophia. His attachment to this imaginary
fair one will preferve him from all the allurements of
unlawful love. Befides, I take care to infpire him
with fuch reverence for himfelf, that notwithftanding
all the fury of his defires, he wall not condefcend to
purfue the enjoyments of debauchery. And though
I may now7 fometimes intruft him to his owrn care, and
not feek to confine him alwrays under my eye j yet ftill
I will be cautious to watch over Iris conduct wTith care¬
ful circumfpeftion.
But as Emilius is to be fhortly introduced to his So¬
phia, it may perhaps be proper for us to inquire into
her character, and in w7hat manner fhe has been brought
. .4* . UP* .
Diftincbve There is a natural difference between the tw7o fexes.
of theftw5 r^le difference in the ftrufture of their bodies, fhows
fexes. them to be deftined by nature for different purpofes in
life, and muft neceffarily occafion a diftincHon between
their chara&ers. It is vain to alk which of them me¬
rits the pre-eminence : each of them is peculiarly fitted
to anfwer the view's of nature. Woman is naturally
weak and timid, man ftrong and courageous; the
one is a dependent, the other a protector. As the
guardian of her virtue, and a reftraint on her defires,
woman is armed with native modefty. Reafon is the
guide and governor of man. When a man and a w7o-
man are united by conjugal vows, a violation of thofe
vowrs is evidently more criminal in the woman than in
the man. The wTife ought to be anfw'erable for the
genuinenefs of the offpring w'ith wrhich (he has been
intrufted by nature- It is no doubt barbarous and
wicked for the hulhand to defraud his wife of the only
reward which fhe can receive for the fevere duties of
her fex : but the guilt of the faithlefs wife is ftill
more atrocious •, and the confequences of her infidelity
are ftill more unhappy.
But if nature has eftablifhed an original diftinffion
betwxen the charafters of the tw7o fexes} has formed
them for different purpofes, and afligned them differ*
ent duties 5 it muft follow, that the education of the Education
one fex ought to be conduced in a manner different v
from that of the other. The abilities common to the
twTo fexes are not equally divided between them 5 but
if that fliare which nature has diftributed to wToman be
fcantier than what fhe has beftowed on man, yet the
deficiency is more than compenfated by the qualities
peculiar to the female. When the woman confines
herlelf to affert her proper rights, fhe has always the
advantage over man ; when (he would ufurp thofe of
the other fex, the advantage is then invariably againft
her.
But we require not that woman Ihould be brought
up in ignorance. Let us confider the delicacy of her
fex, and the duties which fhe is deftined to perform j
and to thefe we may accommodate the edcaution which
we bellow upon her. While boys like whatever is at¬
tended with motion and noife, girls are fond of fuch
decorations as pleafe the eye. Dolls are the favourite
plaything of the fex in their infant years. This is an
original tafte, of the exiftence of which we have the
plaineft evidence. All therefore that we ought to do
is, to trace and bring it under proper regulation. Al¬
low the girl to decorate her baby in whatever manner
fire pleafes j while employed about that, {he will ac¬
quire fuch {kill and dexterity in thofe arts which are
peculiar to her fex, that with fcarce any difficulty {he
will acquire needle work, embroidery and the art of
working lace. Her improvements may even be ex¬
tended as far as defigning, an art fomewhat connected
with tafte in drefs ; but there is no reafon that their
fkill in this art ftiould be carried farther than to the
drawing of foliage, fruits, flowers, drapery, and fuch
parts of the art as bear fome relation to drefs. Al¬
ways aflign reafons for the employment which you
give to young girls, but be fare you keep them con-
ftantly bufy. They ought to be accuftomed to labo¬
rious induftry, as well as to bear the. abridgement of
their liberty. Ufe every art to prevent their work
from becoming difagreeable to them. For that pur-
pofe, let the-mother be careful to make herfelf agree¬
able. A girl who loves her mother or her aunt, will
work cheerfully by them all day 5 while fhe to whom
her mother is not dearer than all the world befides,
feldom turns out well. Never fuffer girls, even at their
diverfions, to be entirely free from reftraint, nor allow
them to run from one amufement to another. If you
now and then deteft your daughter ufing a little artifice
to excufe herfelf from obedience, reffeft that artifice is,
in a certain degree, natural to the fair fex j and as every
natural inclination, when not abufed, is upright and
good, why {hould it not be cultivated ? In order to
give girls proper notions of drefs, let them be taught
to confider fplendour and elegance of drefs, as defigned
only to conceal the natural defedls of the perfon} and
to regard it as the nobleft triumph, the higheft praife,
of beauty, to ihine with unborrowed luftre in the
fimplelt attire. Forbid not young women to acquire
thofe arts which have a tendency to render them agree¬
able. Why refufe them the indulgence of learning to
dance, to fing, and to ftudy fuch other accompliftiments
as afterwards enable them to entertain their hulbands ?
Girls are more difpofed to prattle, and at an earlier
age, than boys. We may now and then find it ne-
ceffary to reftrain their volubility. But the proper
queftion to them on fuch occaffons is not, as to boys.
Of
E I) U
t 5^0 ]
E D U
Education. Of what ufe is thus ? but, What effects will this produce?
v"_ ■' 1 At this early period, when they are yet Grangers to
the diitin6tion between good and evil, and therefore
unable to form a juit judgment concerning any perfon’s
conduct, we ought to reitraiu them carefully from
laying what may be difagreeable to thofe with whom
they converfe.
Girls are no lefs incapable than boys of forming di ■
ilinct notions of religion at an early age. Yet, and
even for that very reafon, religious inftruction Jlhould
be communicated to them much fooner than to the
youth of the other fex. Were we to wait the period
when their mental faculties arrive at maturity, we might
perhaps lofe the happieft time, from our inability to
make a right diftindlion. Since a woman’s conduct is
iubjedt to public opinion, her belief ought therefore
to depend, not on reafon, but on authority. Every
girl ought to follow the religion of her mother, every
married woman that of her huiband. They cannot
derive a rule of faith from their own inquiry. Let us
therefore feek, not fo much to inftrudt them in the
reafons of our belief, as to give them clear diitindt no¬
tions of thofe articles which wre require them to be¬
lieve. Be more careful to inltrucl her in thofe doc¬
trines which have a connexion with morality, than in
thofe myfterious articles which wre are required to be¬
lieve, though wre cannot comprehend them.
Such are the principles on wdiich the education of
Emilius’s unknown miltrefs has been conduced.
[Notwithilanding the merit of that part of this trea-
tife in which the author entertains us wdth the court-
Ihip between his Emilius and Sophia, it does not ap¬
pear to be intimately connected with the fubjecl of
education as to render it proper for us to prefent our
readers with a view of it. We therefore pafs over
the courtlhip, to give a view of our author’s fentiments
concerning the advantages to be derived from travel¬
ling, and the manner in which it ought to be diredt-
ed.J
When Emilius has formed a firm attachment to So¬
phia, and by his afliduities has been fo fortunate as to
gain her affeftions, his great wifh now7 is, to be united
with her in the bonds of marriage. But as he is Hill
young, is but imperfectly acquainted with the nature
of thofe duties incumbent on him as a member of a
particular fociety, and is even ignorant of the nature
of laws and government, I muff feparate him from his
Sophia, and carry him to gain a knowledge of thefe
things, and of the charafler and circumilances of man¬
kind, in various countries, and under various forms of
civil government, by travelling. Much has been faid
concerning the propriety of fending young people to
travel, in order to complete their education. The
multiplicity of books is unfavourable to real knowledge.
We read with avidity, and think that by reading wre
render ourfelves prcdigioufiy wife. But we impofe on
ourfelves : the knowledge wrhich we acquire from books
is a falfe fpecies of knowledge, that can never render us
truly w ife.
To obtain real knowledge, you mull obferve nature
with your own eyes, and lludy mankind. But to gain
this knowledge by travelling, it is not neceffary that
we fliould traverfe the univerfe. Whoever has feen ten
Frenchmen has beheld them all ; and whoever has fur-
42
Emilius at.
tached to a
mi ft refs.
43
Travel.
veyed and compared the circumilances and manners of Education..
ten difierent nations may be faid to know mankind, w—y—j
To pretend that no advantages may be derived from
travelling, becaufe fome of thofe who travel return home
without having gained much real improvement, would
be highly unreafonable. Young people who have had
a bad education, and are fent on their travels without
any perfon to diretl or fuperintend their conduit, can¬
not be expeiled to improve by viliting foreign coun¬
tries. But they whom nature has adorned with vir¬
tuous difpofitions, and have been fo happy as to re¬
ceive a good education, and go abroad with a real de¬
lire of improvement, cannot but return with an in-
creafe of virtue and wrifdom. In this manner lhall E-
milius conduit his travels. To induce him to improve
in the molt attentive manner that time which he Ihould
fpend in travelling, I would let him know, that as he
had now attained an age in wThich it might be proper
for him to form fome determination with regard to the
plan of his future life, he ought therefore to look
abroad into the world, to view the various orders in
fociety, to obferve the various circumltances of man¬
kind under different forms of government, and in
. different parts of the globe •, and to choofe his country,
his llation, and his profelhon. With thefe view's Ihould
Emilius fet out on his travels : and with thefe views,
in the courfe of our travels, w7e Ihould inquire into the
origin of fociety and government, into the nature of
thofe principles by means of which men are united in a
focial Hate, into the various circumilances W'hich have
given rife to fo many different forms of government,
and into the neceffary relation between government and
manners. Our Hay in the great towns Ihould be but
Ihort : for as in them corruption of manners has rifen
to a great height, and dilfipation reigns, a long Hay
in any great town might be fatal to the virtuous dii-
pofitions of Emilius. Yet his attachment to Sophia
would alone be fufficient to fave him from the dangers
to which his virtue is expofed. A young man mull
either be in love, or be a debauchee. Inltances may be
pointed out in which virtue has been preferved w'ithout
the aid of love ; but to fuch inllances I can give little
credit.. . ... 44
Emilius, however, may now 'return to his Sophia. Return
His underllanding is now' much more enlightened than from his
when he fet out on his travels. He is now acquainted travels, and
wdth feveral forms of government, their advantages marru!t
and defeils, with the charadlers of feveral different na¬
tions, and with the effe£ts w'hich difference in circum-
ftances may be expelled to produce on the charadlers
of nations. He has even been fo fortunate as to get
acquainted with fome perfons of merit in each of the
countries w'hich he has vifited. With thefe advantages
gained, and with affection unchanged and unabated, he
returns to his Sophia. After having made him ac¬
quainted with the languages, the natural hiltory, the
government, the arts, culloms, and manners, of fo
many countries, Emilius eagerly informs me that the
period which we had dellined for our travels ^ is now ex¬
pired. I alk, What are then his purpofes for life ? He
replies, that he is fatisfied with the circumilances in
w'hich nature has placed him, and with my endeavours
to render him independent on fortune, and wilhes only
for his Sophia to be happy. After giving him a ffw
advices
4
E D U [56
Education advices for tlie regulation of his conduct in life, I con-
    duel him to his Sophia, and behold him united with her
in marriage. I behold him happy 5 with aflfeaionate
gratitude he bleffes me as the author of his happmefs j
and 1 thus receive the reward of all the pains with
which I have condufted his education.
Remarks. Such are the outUnes of the fyilem of education pro-
pofed by this Angular and original genius. Fo^ongi-
nality of thought, affe&ing fentiment, enchanting de-
fcription, and bold vehement eloquence, this book \s
one of the nobleit pieces of compoiition, not only m
the French language, but even in the whole compafs
of ancient and modem literature. Ihe irregularity of
his method, however, renders it a very difficult talk to
give an abridged view of his work. He conducts his
pupil, indeed,° from infancy to manhood : But inftead
of being barely a {yftem of education, his woik is be-
fides a treafure of moral and philofophical knowledge.
He has chofen a path, and follows it from the bottom
to the fummit of the hill : yet whenever a flower ap¬
pears on the right or left hand, he eagerly fteps afide
to pluck it j and fometimes, when he has once ilepped
afide, a newT obiecl catches his eye and ieduces him
{till farther. Still, however, he returns. His obfer-
vations are in many places loofely thrown together,
and many things are introduced, the want of w hich
would by no means have injured either the unity or the
regularity of his work. If we attempt to review the
principles on which he proceeds in reprobating the pre¬
valent modes of education, and pointing out a new
eourfe, his primary and leading one feems to be, that
we ought to wratch and fecond the deiigns of nature,
without anticipating her. As the tree bloffoms, the
f!owrers blow, and the fruit ripens at a certain period $
fo there is a time fixed in the order of nature for the
fenfitive, another for the intellectual, and another for
the moral powers -of man to difplay themfelves. W e
in vam attempt to teach children to reafon concerning
truth and falfehood, concerning right and wrong, before
the proper period arrive : We only confound their no¬
tions of things, and load their memories with words
without meaning j and thus prevent both their reaion-
ing and moral powers from attaining that itrength and
acutenefs of which they are naturally capable. He at¬
tempts to trace the progrefs of nature, and to mark in
-what manner file gradually raifes the human mind to
the full ufe of all its faculties. Upon the obfervations
which he has made in tracing the gradual progrefs of
the powders of the human mind towards maturity, his
I'yftem is founded.
As it is impoffible to communicate to the blind any
juft ideas of colours, or to the deaf of founds : lo it
muft be acknowledged, that wre cannot poflibly com¬
municate to children ideas which they have not facul¬
ties to comprehend. If they are, for a certain period
of life, merely fenfitive animals, it muft be folly to treat
them during that period as rational and moral beings.
But is it a truth that they are, during any part of life,
guided folely by inftlmft, and capable only of fenfation r
Or, how long is the duration of that period r1 Has na¬
ture unkindly left them to be, till ithe age of twelve,
the prey of appetite and paffion ? So far are the fafts
■of which we have had occalion to take notice, concern¬
ing the hiftory of infancy and childhood, from leading
Vol. VII. Part II.
i ] E D U
to fuch a conclufion, that to us it appears undeniable Education.
that children begin to realon very foon after tiieii en¬
trance into life. Wlien the material world firft opens
on their lenfes, they are ignorant of the qualities and
relations of furrounding oojecls: they know not, for
inftance, wrhether the candle which they look at be neai
or at a diftance j whether the fire with which they are
agreeably warmed may alfo affect them witn a painful
fenfation. But they remain not long in this ftate ot
abfolute ignorance. T. hey loon appear to have acquir¬
ed fome ideas of the qualities and relative fituation oa
bodies. They cannot, however, acquire iuch ideas,
without exerting reafoning powers in a certain degree.
Appearances muft be compared, and inferences drawn,
before knowledge can be gained. It is not fenlation
alone which informs us of the relative diftances oi^ bo¬
dies j nor can fenfation alone teach us, that the fame
effedts which we have formerly obferved will be again
produced by the fame caufe.
But if children appear capable of reafoning at a very
early period, they appear alfo to be at a very early pe-.
riod fubjedl to the influence of the paffions : they are
angry or pleafed, merry or lad, friends or enemies,
even while they hang at the breaft j inftead of being
felfifn, they are naturally liberal and focial. And if
we obferve them with candid attention, we will find
that the paffions do not difplay themlelves fooner than
the moral fenfe. As nature has wifely ordered, that we
ftiould not fee, and hear, and feel, without being aole
to compare and draw inferences from our perceptions j
fo it is a no lefs certain and evident law of nature, that
the paffions no fooner begin to agitate the human
breaft, than we become able to diftinguilh the beauty
and the deformity of virtue and vice. Ihe child is not
only capable of gratitude and attachment to the perfon
who treats him with kindnefs j he is alfo capable of
diftinguifiiing between gratitude and ingratitude, and
of viewing each with proper fentiments. He cries
when you refule to gratify his defires j but he boldly
infifts that he is injured when you ufe him cruelly or
unjuftly. It is indeed impoflible to attend to the con-
duft of children during infancy, without being convin¬
ced that they are, even then, capable of moral diftinc-
tions. So little are they acquainted with artificial lan¬
guage, that we and they do not then well underftand
each other. But view their actions *, confider thofe figns
by which nature has taught them to exprefs themfelves.
Our limbs, our features, and our lenfes, are not gradual¬
ly and by piecemeal bellowed as we advance towards
maturity the infant body comes not into the world
mutilated or defective : why then, in point of mental
abilities, ftiouid we be for a while brutes, without be¬
coming rational and moral beings till the fulnefs of
time be accomplilhed ? All the differences between the
phenomena of manhood and thofe of infancy and child¬
hood may be accounted for, if we only refled, that
when children come into the world, they are totally un¬
acquainted with all the objects around them j with the
appearances of nature, and the inftitutions of fociety $
that they are fent into the world in a feeble ftate, ia
order that the helpleffnefs occafioned by their ignorance;
may attract the notice and gain the affiftance of thofe
who are able to help them j and that they attain not
full ftrength in the powers, either of mind or body,
4 B nor
E D U [ 552 ]
Education, nor a fufficient acquaintance with nature, with artifi-
; v cial language, and with the arts and inftitutions of fo-
ciety, till they arrive at manhood.
Even Rouileau, notwithilanding the art with which
he lays down his fyltem, cannot avoid acknowledging
indire&ly, on feveral occafions, that .our focial difpo-
litions, our rational and our moral powers, difplay
themielves at an earlier period than that at which he
wilhes us to begin the cultivation of them.
But though the great outlines of his fyilem be mere¬
ly theory, unfupported by facts, nay plainly contra¬
dictory to fadtsj yet his obfervations on the improprie¬
ty or abfurdity of the prevalent modes of education
are almolt always juft, and many of the particular di¬
rections which he gives for the conducing of education
are very judicious. He is often fanciful, and often de¬
viates from the common road, only to thaw that he is
able to walk in a leparate path. Yet why fhould he
be oppofed with fo much virulence, or branded with fo
many reproachful epithets ? His views are liberal and
extenlive : his heart feems to have glowed wdth bene¬
volence : his book contains much obiervation of human
actions 5 difplays an intimate acquaintance with the mo¬
tives which fway the human heart 5 and if not a perfect
fyftem for- education, is yet fuperior to what any other
writers had before done upon the fubjeCt. It is furely
true, that we curfelves often call forth evil paflions in
the breads of children, and imprefs them with bad ha¬
bits : it is no lefs true that we put books in their hands,
and load their memory with words, when we ought ra¬
ther to direCl their attention to tilings, to the pheno¬
mena of nature, and the fimplert arts of life. The form
in which he has chofen to communicate his fentiments
on the fubjeCl of education renders the perufal of it
more plealing, and his precepts more plain, than they
would othenvife have been : it is nearly that dramatic
form with which we are fo much delighted in fome of
the nobleil compofitions of the ancients.
_ After viewing the public ellablilhments for educa¬
tion which exifted in fome of the mod renowned dates
of antiquity ; and after lidening to the fentiments of
the experienced Quindfilian, the learned Milton, the-
judicious Locke, and the bold fanciful Roufleau, on
this intereding fubjedf ; it may now be proper to lay
before the reader our own fentiments concerning the
education of youth under a few didinft heads.
Indeed, if we w-ere difpofed to give abridgments of all
the books which have been written on the fubjeft of edu¬
cation, or even to hint at all the various modes which
have been recommended by teachers or theorids, we
might fwell this article to an amazing fize : Nay, were
we only to take notice of the many elegant and fen-
dble writers who have of late endeavoured to call the
attention of the public to this lubject, we might ex¬
tend it to an immoderate length. A Karnes, a Pried-
ley, a Knox, a Madame de Sillery, and a Berquin,
might well attraft and fix our attention. But as,
among fuch a crowd of waiters, every thing advanced
by each cannot be original 5 and even of thofe things
which are original, only a certain, and that perhaps
even a modeiUte, proportion, can be jud and judicious 5
and as they often either borrow from one another, or
at lead agree in a very friendly manner, though in fome
things they profefs a determined hodility j therefore
E D u
we diall content ourfelves with having taken notice of Education.
tour of the mod refpeftable writers on the lubjetd.  v——*
, Prfknting to our readers the refult of our own
oofervations and rededtions, we diall throw7 our thoughts
nearly under the following heads. The management of
children from their birth till they attain the age of five
or fix; from that period till the age of puberty j and from
that age till manhood 5 private and public education •, re¬
ligion and morals; the languages 5 natural philolophy •
the education of people of rank and fortune ; education
of perlons defigned for a mercantile employment, and
for the other humbler occupations in aefive life not
particularly connefted with literature } education of the
female fex ; foreign travel; knowledge of the world 5
and entrance into aftive life. We do not pretend to
be able to include under thefe heads every thing worthy
of notice in the fubjeft of education: but under thefe
we wall be able to comprehend almoft every thing of
importance that has occurred to us on the fubjeft.
I. On the Management of Infants from the Time of their
Birth till they attain the Age offive or fix.
The young of no other animal comes into the
world in fo helplefs a ftate, or continues fo long to
need afliltance, as that of the human fpecies. The
calf, the lamb, and the kid, are vigorous and live¬
ly at the inftant of their birth j require only, for a very
ftiort period, nourilhment and proteftion from their re-
fpeftive dams ; and foon attain fuch degrees of ftrength
and aftivity as to become entirely independent. The
infancy of the oviparous animals is not of longer con¬
tinuance : And, indeed, whatever department of the
animal world w-e may choofe to furvey, we Hill find that
no fpecies is fubjeff to the fame fevere laws as man
during the firfl period of life.
Yet the charaffer and the views of man are fo very
difterent from thofe of the other animals, that a more
careful attention to thefe may perhaps induce us to re¬
gard this feeming feverity rather as an inftance of the
peculiar kindnefs of the Author of nature. From every M
obfervation which has been hitherto made on the powers parT/tT'
and operations of the inferior animals, we are led to con- other ani-
fider them as guided and afluated chiefly, if not folely, niab» ‘n re-
by inlfindf, appetite, and fenfation: their view's extend lped* t0 the
not beyond the prefent moment 3 nor do they acquire
new knowdedge or prudence as they advance in life.
But the chara&er of the human race is much more ex¬
alted. We have alfo powers and organs of fenfation,
inllin&s and appetites 5 but thefe are the moft ignoble
parts of our nature : our rational faculties and moral
powers elevate us above the brutes, and advance us to
an alliance with fuperior beings. Thefe rational facul¬
ties and moral powers render us capable of focial life,
of artificial language, or art, of fcience, and of religion.
Now, w'ere one of the fpecies to come into the world
full grown, poffefied of that bodily lirength and vigour
which diftinguiflies manhood, his ignorance wrould Hill
render him inadequate to the duties of life; nay,
would even render him unable to procure means for his
fubfiftence : while his manly appearance wmuld deprive
him of the compaflion and benevolent afliftance of
others ; and his ftrength and vigour would alfo render
him lefs docile and obedient than is necelfary, in order
that
E D U T 56.3 1 E D U
Education, tliat he may receive inftruftion in the duties and arts
u v ' of life. Again, were the period of infancy as fhort to
the human fpecies as to the other animals 5 were we
to be no longer fubjetted to a parent’s authority, or
prote&ed by his care, than the bird or the quadruped 5
we ihould be expofed to the dangers and difficulties of
the world before we had acquired fufficient knowledge
or prudence to conduct us through them, before we
had gained any acquaintance with the ordinary pheno¬
mena of nature, or were able to ufe the language or
practife the arts of men in a focial Hate.
Since then, it is by the benevolence of nature that
we are feeble and helplefs at our entrance into life,
and that our progrefs towards maturity is (low and
gradual 5 lince nature has deltined us to be for a con-
iiderable time under the care and authority of our pa¬
rents and lince the manner in which we are managed
during that early part of life has fo important an in¬
fluence on our future charafter and conduft : it is
therefore incumbent on parents to diredt that tender-
nefs, which they naturally feel for their offspring, in
fuch a manner as to fecond the views of nature.
When children come into the world, inffindl diredls
them to receive nourilhment from the breaft, and
* to claim attention to their pains and wants by crying.
We attend to their ligns, and ftrive to render them as
(prefsof in-eafy as we can* They are waffied, clothed with fuch
fants. garments as we think moff fuitable, and fuckled either
by their mother or by fome other woman who is con-
fidered as proper for the purpofe. The abfurd mode
of fwaddling up infants in fuch a manner as to confine
them almolt from all motion, and leave fcarce a limb at
liberty, which has been fo often exclaimed againlt and
Ireprefented as highly injurious to the fymmetry and vi¬
gour of the human frame, is now almoft entirely laid a-
lide ; and therefore we need not raife our voice ^gainft
it. Still, however, there are certainly too many pins
- and bandages ufed in the drefs of infants : thefe are un¬
favourable to the circulation of the blood, impede the
growth, and often occafion thofe tears and that peevilh-
nefs which we ralhly attribute to the natural ill humour
of the poor creatures. Their drefs ought to be loofe
and cool, fo as to prefs hard on no joint, no vein nor
mufcle j and to leave every limb at liberty. If too
heavy and clofe, it may occafion too copious a perfpi-
ration, and at the fame time confine the matter perfpi-
red on the furface of the fkin ; than which nothing can
be more prejudicial to the health of the child. It may
alfo, however, be too thin and cool: for as moderate
warmth is neceffary to the vegetation of plants *, fo it is
no lefs neceffary for promoting the growth of animals :
and, therefore, though the drefs of infants ought to be
43 loofe and eafy, yet Hill it Ihould be moderately warm.
N-uries. It is common for mothers in affluent or even in
comfortable circumftances, to forego the pleafure of
nurfing their own children, that they may avoid the fa¬
tigues with wfflich it is attended. This practice has
long prevailed in various ages and among various na¬
tions : it has been often reprobated with all the warmth
of paffion, and all the vehemence of eloquence, as dilho-
nourable, inhuman, contradiftory to the defigns of
mature, and deftrudlive of natural affection : yet itill it
prevails ; fathers and mothers are Hill equally deaf to
the voice of nature and the declamations of philofo-
phera. Indeed, in a luxurious age, fuch a pradlice may
be naturally expected to prevail. In iuch an age, tney ^riuiat'Oiv
who are poffeffed of opulence generally perfuade them-
felves, that, to be happy, is to fpend their time wholly
amid diverfions and amufements, without defcending to
ufeful induitry, or troubling themfelves- about the ordi¬
nary duties of life. Influenced by fuch notions, they
think it proper for them to manage their family affairs,
and to nurfe and educate their children, by proxy ; nay,
to do for themfelves nothing that another can perform
for them. It is vain to make a ferious oppofition to
thefe abfurd notions 5 the ialfe views of happinefs, the
pride and the indolence produced by luxury, will ftill
be too powerful for us. We mutt not hope to per¬
fuade the mother, that to receive the careffes, to
behold the fmiles, and to mark the bodily and mental
powers of her child in their gradual progrefs towards
maturity, would be more than a fufficient compenla-
tion for all the fatigues which Ihe wmuld undergo in
nurfing and watching over him in his infant years. V» e
need not mention, that the mutual affection between a
mother and her child, which is partly the effedl of in-
ftinft, depends alfo, in no inconliderable degree, on
the child’s fpending the period of infancy in its mo¬
ther’s arms } and that when (he fubftitutes another in
her place, the child naturally transfers its affedtion to
the perfon who performs to it the duties of a mother.
We need not urge thefe, nor the various other reafons
which feem to recommend to every mother the province
of fuckling her own children, and watching over their
infant years y for we wall either not be heard, or be
liftened to with contempt. Yet we may venture to fug-
geft, that if the infant muff be committed to a ftran-
ger, fome degree of prudence may be employed in fe-
ledling the perfon to whom he is to be intrufted.
Her health, her temper, and her manner of fpeaking,
muff be attended to. A number of other qualifica;-
tion are alfo to be required in a nurfe : but it is rather
the buffnefs of the phyfician to give direftions with re¬
gard to thefe. If her habit of body be any way un¬
healthy, the conftitution of the infant that fucks her
milk cannot but be injured : if her temper be rough or
peeviffi, the helplefs child fubjedled to her power will
be often harfhly treated } its fpirit will be broken, and
its temper foured : if her pronunciation be inarticulate
or too rapid, the child may acquire a bad habit when
it firft begins to exert its vocal organs, which will not
be eattly correfted. 49
In the milder feafons of the year, infants ought to Influence of
be frequently carried abroad. Not only is the open ‘eAtjnent
air favourable to health, but the frelhnefs, the beau- ^
ty, the variety, and the lively colours of the fcenes jjt;es and
of nature, have the happieft effefts on the temper, and difpofmons,
have even a tendency to enliven and invigorate the
powers of the mind. At this period, the faculties of
the underftanding and the difpolitions of the heart
generally acquire that particular bias, and thofe di-
ftinguifhing features, which charafterize the individual
during the future part of his life, as quick or dull,
mild or paflionate; and which, though they be gene¬
rally attributed to the original conformation of the
mind by the hand of nature, yet are owing rather to
the circumftances in which we are placed, and the
manner in which we are treated, during the firft; part'
of life. v
When children begin to walk, our fondnefs difpofes
4 B 2 us
E D U [
Education, us to adopt many expedients to aflift them. But thefe
v feem to be improper. It is enough for us to watch
over them fo as to guard them from any danger which
they might otherwife incur by their firit attempts to
move about. Thofe w*ho advife us not to be too an¬
xious to preferve children from thofe flight hurts to
which they are expofed from their difpofltion to acti¬
vity, before they have acquired fufficient ftrength or
caution, certainly give a judicious piece of advice
which ought to be liilened to. By being too atten¬
tive to them, we teach them to be carelefs of them-
ielves j by i'eeming to regard every little accident
which befals them as a molt dreadful calamity, we in-
ipire them with timidity, and prevent them from ac¬
quiring manly fortitude. When children begin to lifp
out a few words or fyllables, the pleafure which we
feel at hearing them aim at the ufe of our language,
dilpofes us to liflen to them with fuch attention as to
relieve them from the necelnty of learning an open
diftincl articulation. Thus we teach them to exprefs
themfelves in a rapid, indillinft, and helitating man¬
ner, which we often find it difficult, fometimes even
impoffible, to correCl, when they are farther advanced.
Would we teach them a plain dillinCt articulation,
we ought not only to fpeak plainly and diftinCtly in
their prefence, but alfo to difregard their queftions and
requells, if not exprelfed with all the opennefs and
diltinctnefs of pronunciation of which they are ca¬
pable.
Man is naturally an imitative animal. Scarce any
of our natural difpofitions is difplayed at an earlier pe¬
riod than our difpofition to imitation. Children’s
firil amufements are dramatic performances, imitative
oi the arts and addons of men. This is one proof
among others, that even in infancy our reafoning fa¬
culties begin to difplay themfelves; for we cannot
agree wdth fome philofophers that children are a ciliat¬
ed and guided folely by inllincl in their attempts at
imitation.
However that be, the happiefl ufe might be made
of this principle which difcovers itfelf fo early in the
infant mind. Whatever you wilh the child to acquire,
do in his prefence in fuch a manner as to tempt him
to imitate you. Thus, without fouring his mind by
relfraint during this gay innocent period of life, you
may begin even now to cultivate his natural powrers.
Were it impoffible at this time to communicate any
infl.ruclion to the boy, without banilhing that fpright-
ly gaiety which naturally diftinguiffies this happy age,
it would be bed to think, only how he might lofe his
time in the leal! difadvantageous manner. But this
is far from being necelfary. Even now the little crea¬
ture is difpofed to imitation, is capable of emulation,
and feels a defire to pleafe thofe whofe kindnefs has
gained his affeclion. Even now his fentiments and
conduct may be influenced by rewards wffien prudently
bellowed, and by punifhments when judicioufly in¬
flicted. Why then Ihould w e hefitate to govern him
by the fame principles, by which the laws of God and
fociety aflert their influence on our own fentiments
and conduCt ? Indeed, the imprudent manner in which
children are too generally managed at this early period,
W'ould almoft tempt us to think it impoffible to inftruCt
them, as yet, without injuring both their abilities and
difpofitions. But this is owing folely to the careieffhefs,
E D U
conduCt of thofe under whofe Edacatioe.
564 ).
ftupidity, or capricioti:
care they are placed.  v 
Is implicit obedience to be exaCted of children ? and 5°
at what period of'life fliould we begin to enforce it • whether06
As children appear to be capable both of reafoning and ant/when,
of moral diltinCtions at a very early age ; and as they to be exadh
are fo weak, lo inexperienced, lo ignorant of thecd*
powers of furrounding bodies, and of the language,
inllitutions, and arts of men, as to be incapable of
fupporting or conduCling themfelves without direc¬
tion or allillance j it leems therefore proper that they
be required even to fubmit to authority. To the ne-
ceffity of nature both they and we mult on many oc-
cafions fubmit. But if the will of a parent or tutor
be always found fcarce lefs unalterable than the ne-
ceffity of nature, it will always meet with the fame
refpeCtful fubmiffive resignation. It may not perhaps
be always proper to explain to children the reafons
for which we require their obedience : becaule, as the
tange of their ideas is much lefs extenfive than ours j
as they do not well underftand our language, or com¬
prehend our modes of reafoning j and as they are now
and then under the influence of paffion and caprice, as
WTell as people who are farther advanced in life ; we
are therefore likely to fail in making them compre¬
hend our reafons, or in convincing them that they
are well grounded. And as it is proper to exaCf obe¬
dience of children ; fo we fliould begin to require it as
foon as they become capable of any conliderable degree
of activity. Yet we mull not confine them like Haves,
without allowing them to fpeak, to look, or to move,
but as we give the word. By 1'uch treatment we could
expe61 only to render them peevifli and capricious. It
will be enough, at firfl, if we let them know that obe¬
dience is to be exafted ; and if we reftrain them only
where, if left at liberty, they wrould be expofed to im¬
minent danger.
If then, at fo early a time of life as before the age ox
five or fix, it is pollible to render children obedient,
and to communicate to them inilru&ion 5 what arts,
or what learning, ought we to teach them at that pe¬
riod ? To give a proper anfwer to this quellion, is no
eafy matter. It feems at firit difficult to determine,
wfietfier we ouglit yet to initiate tfiem in letters. But
as their apprefienfion is now quick, and their memory
pretty tenacious, there cannot be a more favourable
time for this very purpofe. As foon as they are ca¬
pable of a diftinft articulation, and feem to pofiefs any
power of attention, we may with the greateft propriety
begin to teach them the alphabet. The moil artful,
alluring methods may be adopted to render the horn¬
book agreeable •, or we may ufe the voice of authority,
and command attention for a few minutes j but no
harfhnefs, no feverity, and fcarce any reftraint. At the
fame time, it will be proper to allow the little creatures
to run much about in the open air, to exercife their
limbs, and to cultivate thofe focial difpofitions which
already begin to appear, by playing with their e-
quals.
Such are the thoughts which have fuggefted thenv
felves to us concerning the management of children in
mere infancy. What an amiable little creature would the
boy or girl be, who were brought up in a manner not
inconfiftent with the fpirit of thefe few hints ? Behold
him healthy and vigorous, mild, fprightly, and cheer¬
ful;
E D U
[ 565 1
F, D U
Education, (ul: He is fubmiflive and docile, yet not dull or timid ;
V ' he appears capable of love, of pity, and of gratitude.
His mind is hitherto, however almoft wholly main-
formed : he is acquainted but with a few of the oojects
around him-, and knows but little of the anguage,
manners, and-inftitutions of men : but he ieels the m-
pulfe of an ardent curiofity, and all the powers oi his
mind are alive and active.
II. On the Management of Children between the Age of
five or fix and the Age of Pubcrtij.
At this period it may be proper, not only to exaft
obedience, and to call the child’s attention for a few
minutes now and then to thofe things of which the
knowledge is likely to be afterwards ufeful to him :
but we may now venture to require .of him. a regular
Heady application, during a certain portion of his
time, to fuch things as we with him to learn. Before
this time it would have been wrong to confine his at¬
tention to any particular talk. I he attempt could
have produced no other efTed than to deifroy his na¬
tural gaiety and cheerfulnefs, to blunt the natural quick-
nefs of his powers of apprehenfion, and to render hate¬
ful that which you wilhed him to acquire.
however, the cafe is fomewhat different : 1 he child, is
not yet fenfible of the advantages which he may derive
from learning to read, for inftance ; or even though
he were able to forefee all the advantages which he
will obtain by ikill in the art of reading through the
courfe of life j yet is it the charaffer of human nature,
at every Itage of life, to be fo much influenced by pre-
fent objeds in preference to future views, that the
fenfe of its utility alone would not be fufticient to in¬
duce him to apply to it. Even at the age of 1.2, o
20, of 50 j nay, in extreme old age, when reafon is be¬
come very perfpicacious, and the paflions are mortifi¬
ed ; Hill we are unable to regulate our condud folely
by views of utility. Nothing could be more abfurd,
therefore, than to permit the child to fpend his time
in foolifh tricks, or in idlenefs, till views of utility
Ihould prompt him to fpend it in a different manner.
No let us begin early to habituate him to applica¬
tion and to the induflrious exertion of his powers. By
endowing him with powers of adivity and. apprehem
fion, and rendering him capable of pu.rfuing with a
Heady eye thofe objeds which attrad his defires, na*
ture plainly points out to us in what manner w e ougnt
to cultivate his earlier years. Befides, wre can com¬
mand his obedience, we can awaken, his curiofity, we
can roufe his emulation, we can gain his. affedion, we
can call forth his natural difpofition to imitation, and
we can influence his mind by the hope of reward and
the fear of punifhment. When we have fo many means
of efiablifhing our authority over the mind of the boy
without tyranny or ufurpation y it cannot furely be dif¬
ficult, if we are capable of any moderation and pru¬
dence, to cultivate his powers, by. making him begin
at this period to give regular application to fomething
SI that may afterwards be ufeful.
A know- And if the boy muH now- begin to dedicate fome
ledge of portion of his time regularly to a certain talk, what
words and tafl. win be moft fuitable ? Even that to which children
muVbf are ufually firH required to apply ;, continue teaching
learnt at the him to read. Be not afraid that his abilities wall fufler
fame. time.
from an attention to books at fo early an age. Say not Fa ucation.
that it is folly to teach him words before he. have gain¬
ed a knowledge of things. It is neceflary, it is the de-
fign of nature, that he Ihould be employed in acquiring
a know-ledge of things, and gaining an acquaintance with
the vocal and written figns by which we denote them,
at the fame time, t hefe are intimately connected ^
the one leads to the other. When you view any ob¬
ject, you attempt to give it a name, or fe^k to. learn
the name by w-hich men have agreed to diffinguifh it :
in the fame manner, when the names of fubffances or.
of qualities are communicated to us, we are defirous or
knowing what they lignify. At the fame time, lb
imperfect is the knowledge of nature w-hich. children
can acquire from their own unaffiffed obfervation, tnat
they muff have frequent recourfe to our affiffance be¬
fore they can form any diffinct notions of thofe objects
and feenes which they behold. Indeed language can¬
not be taught, without teaching that k is merely a
fyffem of figns, and explaining what each particular
fign is defigned to lignify. If, therefore, language is
not only neceffary for facilitating the mutual inter-
courfe of men, but is even ufeful for enabling.us to
obtain fome know-ledge of external nature, and if the
knowledge of language has a natural tendency to ad¬
vance our knowledge of things} to acquaint ourfelves
w-ith it muff therefore be regarded as an objedl of the
higheff importance : it mult alfo be regarded as one of
the firff objects to which we ought to direeff the atten¬
tion of children. But the very fame realons which
prove the propriety of making children acquainted with
thofe artificial vocal figns w-hich we ufe to exprefs our
ideas of things, prove alfo the propriety of teaching
them thofe other figns by which we exprefs thefe in
writing. It is poffible indeed, nay it frequently hap¬
pens, that we attempt to inffruf! children in. language
in fo improper a manner as - to confound their notions
of things, and to prevent their intellectual powers
from making that improvement of which they are na¬
turally capable j but it is alio poflible to initiate them
in the art of reading, and in the know-ledge of lan¬
guage, w-ith better aufpices and happier effeCls. I he
know-ledge of language may be confidered as the key
by which w-e obtain accefs to all the flores of natural
and moral knowledge.. _ 52
Though we now agree to confine our pupil to a cer- Confine-
tain talk,.and have determined that his firff talk lhallbe roenb^1°^r
to learn to read 5 yet we do not mean to require that lU 1 ^e
he be confined to this talk during the greateft part of
the day,.or that his attention be ferioully direCled to no
other obje&. To fubjeCt him to too fevere reftraint
would produce the. molt unfavourable effeCts on his ge¬
nius, his temper, and his difpofitions. It is in * confe-
quence of the injudicious management of children, while
they are fometimes fuffered to run riot, and at other
times cruelly confined like pritoners or llaves ; it is in
confequence of this, that w-e behold fo many inftances
of peevilhnefs, caprice, and invincible averfion to all
ferious application at this period of life. But were a
due medium obferved, were reftraint duly tempered
with liberty and indulgence, nothing would be more
eafy than to difpofe children to cheerful obedience,
and to communicate to them inftruCtion at this age.
That part of their time which they are left to enjoy
at liberty, they naturally dedicate to their little fports.
E K u f 566 ]
JMKn™. The favourite fports of boys are generally aftive ; thofe him hi
V ^ nr mvle \C __ _1 1 , '
of girls, fedentary. Of each we may take 'advantage,
to prepare them for the future employments of life!
However, neither are the amufements of boys invari-
ab.y active, nor thofe of girls always fedentary : for
as vet,, the manners and diipofitions of the two fexes
are diihnguilhed rather by habit or accident than by
nature. I he difpolition to aftivity which charafter-
izes children, is no lefs favourable to health than to
the u- improvement in knowledge and prudence 5 their
aflive fports have a tendency to promote their growth
and add new.vigour to their limbs. Perhaps, even at
this time, children might be enticed to learn the ele¬
ments of natural philofophy and natural hiftory amid
-their amufements and fports. Birds, butterflies, dogs,
and other animals, are now favourite objects of their
care ; their curiofity is powerfully roufed by the ap¬
pearance of any ftrange objeft; and many of the fim-
pleft experiments of. natural philofophy are fo plealing
that they cannot fail to attracf the attention even of
tnole. -who are leaf! under the influence of curiofity.
Yct it wouid be improper to infill on their attention
to thele things as a talk : if we can make them regard
them as amufements, it will be well j if not, we mult
defer them to feme happier feafon. They might alfo
y proper management, be led to acquire feme Ikill in
the arts. They build mimic houfes, and fill them with
luitable furniture j they.conltrucl little boats, and fail
tnem they will fence-in little gardens, and cultivate
them j and we even fee them imitate all the labours
o the hufbandman. Such is the pleafure which man
naturally feels in exerting his powers, and in a&ing
with delign. Let us encourage this difpofition. Thele
are the moll fuitable amufements in which they can
\ 53 engage.
molt r)sn°kS AS the b°y’S attent!on to ^terary objects is Hill fop-
‘ 1 - pofed to be continued, he will foon be able to read
with fome corre&nefs and facility. It becomes an ob¬
ject of importance, and of no fmall difficulty, to deter¬
mine what books are to be put into his hands, and in
"hat manner his literary education is to be conduced.
After the child is made acquainted with the names
and powers of the letters, with their combination into
fyllables, and with the combination of thefe again into
words, fo that he can read with tolerable facility j it
will, be proper that the pieces of reading which are
put into his hands be fuch as are deferiptive of the ac¬
tions of men, of the feenes of external nature, and of
the forms and characters of animals. With thefe he is
already m fome degree, acquainted j thefe are the ob-
je.6ts.of his daily attention j beyond them the range of
his ideas does not yet extend •, and therefore other
fubjefts will be likely to render his talk difagreeable to
him. Befides, our prefent obje6t is to teach him
words : in order to teach him words* we mull let him
know their fignification 3 but till he have acquired a
very confiderable knowledge of language, till he have
gained a rich fund of fimple ideas, it will be impoffible
for him to read or to hear with underftanding on anv
other fubjedl.but thefe. And let us not as yet be par¬
ticularly anxious to communicate to him religious or
moral inllrudHon, otherwife than by our example, and
by caufing him to a6l in fuch a manner as we think
molt proper. Our great bufinefs at prefent is, to
.make him acquainted with our language, and to teach
s
per.
E D u
. wh;t ‘nmn« we ufe it to exprefi cur ideas. Ednotior.
m r °Tl obltrvatlon> an(i b7 our inllrudlion, he1 v—'
vuil loon become capable of comprehending all that
we with to communicate : But let us not be too hafty •
the boy cannot long view the aftions of mankind, and’
oblerve the economy of the animal and the vegetable
world, without becoming capable of receiving both
^religious and moral inltrudiion when judicioully com-
As foon as the pupil can read and fpell with tolera- Writing,
ble facility, and has acquired fufficient ilrength of
aim and. fingers to hold a pen, it may be proper to
initiate him in the art of writing. If this art is not
made difagreeable by the manner in which his applica¬
tion to it is requited, he will learn it without diffi-
cu ty Children’s natural difpofition to imitate, parti¬
cularly whatever depends on manual operation, renders
this art peculiarly eafy and pleafing to them, when
they are not harffily forced to. apply to it, nor fuffered
to get into a habit of performing their talk with hafle
and negligence.
• ‘Il: r^l!lres lndeed the moll cautious prudence, the Reftraint
me ell delicacy, and the moll artful addrefs, to prevail
with children to give a cheerful and attentive apnlica-
tion to any appointed talk. If you are too Hern and
rigid m enforcing application, you may feemingly ob¬
tain your objecl : the child fits motionlefs, and fixes
his eye on his book or copy 5 but his attention you
cannot command ; his mind is beyond your reach, and
can elude your tyranny; it wanders from the prefent
oojedls, and flies with pleafure to thofe feenes and ob-
jeels .111 which it has found delight. Thus you are dif-
appomted of your purpofe 5 and, befides, infpire the
child with luch averfion both to you and to thofe obiedts
to which you wiffi him to apply, that perhaps at no
future period will he view learning otherwife than with
dffigulL ^
gentlenefs, and the arts of infinuation, will Gentknefs.
not ahyays be fuccefsful. If you permit the child to
apply juil when he pleafes 3 if you liilen readily to all
his pretences and excufes ; in fhort, if you feem to
confider learning as a matter not of the highell im¬
portance, and treat him with kindnefs while he pays
but little attention and makes but flow progrefs 3 the
confequences of your behaving to him in this manner
will be fcarce lels unfavourable than thofe which at¬
tend imprudent and unreafonable feverity. It is how¬
ever, fcarce poffible to give particular diredions how to
treat children fo as to allure them to learning, and at
the fame time to command their ferious attention.
But the prudent and affedlionate parent and the judi¬
cious tutor will not always be unfuccefsful 3 fince there
are fo many circumllances in the condition of children,
and fo many principles in their nature, which fubjedl
them to our will.
. ^ be principles of arithmetic ought to make a part Arithm©.
m tne boy’s education as foon as his reafoning powerstic.
appear to. have attained fuch ilrength and quicknefs
that he will be able to comprehend them. Arithme-*
tic affords more exercife to the reafoning powers of
the mind than any other of thofe branches of learning
to which we apply in our earlier years: and if the child’s
attention be diredted to it at a proper period, if he be
allowed to proceed flowly, and if care be taken to make
him comprehend fully the principles upon which each
particular
E D U
[ 567 1
£ D U
Education, particular operation proceeds, it will contribute much
‘ to increafe the ilrength and the acutenefs of the powers
of his underftanding.
Where the learned languages are regarded as an ob¬
ject worthy of attention, the boy is generally initiated
in them about this time, or perhaps earlier. We have
relerved to a feparate head the arguments which occur
to us for and againit the practice of inftructing chil¬
dren in the dead languages} and {hall therefore only
obferve in this place, that the itudy of them ought not
to engrofc the learner’s attention fo entirely as to ex-
58 elude other parts of education.
Pradiical From arithmetic our pupil may proceed to the prac-
mathema- tjca] branches of the mathematics: And in all of thefe,
tlcs* as well as in every other branch of learning, what you
teach him will be bell remembered and moil thorough¬
ly underftood, if you afford him a few opportunities of
applying his lelfons to real uie in life. Geometry and
geography are two moil important branches of educa¬
tion^ but are often taught in fuch a manner, that no
real benefit is derived from the knowledge of them. The
means which Roulfeau propofes for initiating young
people in thefe and in feveral other of the arts and
fciences are excellent-, and if judicioufiy applied, could
hardly fail of fuccefs.
While boys are engaged in thefe and in the lan¬
guages, they may alfo attend to and cultivate the bo¬
dily exercifes 5 fiich as dancing, fencing, and horfe-
manfhip. Each of thefe exercifes is almoft abfolutely
necefiary for one who is defigned to have intercourfe
with the world; and befides, they have a tendency to
render the powers of the body adtive and vigorous,
and even to add new courage and firmnefs to the
mind.
When our pupil has acquired fome knowledge of
cifesin com-his own and of the learned languages, has gained
pofition. fome {kill in the principles of arithmetic and of prac¬
tical mathematics, and has received fome inlfrucfion
in the principles of morality and religion, or even be¬
fore this time, it will be proper to begin him to the
pradlice of compofition. Themes, verfions, and let¬
ters, the fir ft exercifes in compofition which the boy is
ufually required to perform, none of them feems hap¬
pily calculated for leading him to increafe his know¬
ledge, or to acquire the power of expreiTmg himfelf
with eafe and elegance. Without enlarging on the
impropriety or abfurdity of thefe exercifes, we will
venture to propofe fomething different, which we can¬
not help thinking would conduce more eft'ebtually to
the end in view. It has been already obferved, that
the curiolity of children is amazingly eager and aftive,
and that every new objeft powerfully attrafts their re¬
gard : but they cannot view any obi eft without tak¬
ing notice of its molt obvious qualities any animal,
for inftance, without taking notice of its fhape, its
colour, its feeming mildnefs or ferocity and they are
generally pretty ready to give an account of any thing
extraordinary which they have obferved. How eafy
then would it be to require them to write down an ac¬
count of any new objeft expofed to their obferva-
tion ? The* talk would not be difficult 5 and every
new piece of compofition which they prefented to us
would add fo much to their knowledge of nature. We
might even require fuch fpecimens of their accuracy of
ohfervation and {kill in language, at times when they
59
Firft exer-
enjoyed no opportunities of beholding new or furprif- Education,
ing objefts j a tree, a flower, a field, a houle, an ani-
mal, any other fimple objeft, ihould be the fubjeft of
their exercife. After fome time, we might require
them to deferibe fomething more various and complex.
They might give an account of feveral objefts placed
in a relative fituation j as, a ftream, and the vale
through which it flows; or, a bird, and the manner
in which it conftrufts its neftor, of one objeft fuc-
ceflively afluming various appearances, as the bud, the
flower, the apple. Human aftions are daily expofed
to their obfervation, and powerfully attraft their at¬
tention. By and by, therefore, their talk Ihould be
to deferibe fome aftion which had lately paffed in their
prefence. We need not purfue this hint farther ; but,
if we miftake not, by thefe means young people might
fooner, and much more certainly, be taught to exprefs
themfelves with eafe and correftnefs in writing, than
by any of the exercifes which they are at prefent
caufed to perform with a view to that. Befides, they
would at the fame time acquire much more real know¬
ledge. The ftudy of words would then be rendered
truly fubfervient to their acquiring a knowledge of
things.
We cannot defeend to every particular of that feries
of education in which we wifh the boy to be engaged
from that period when he firft becomes capable of fe-
rious application till he reach the age of puberty. It
is not neceffary that we Ihould, after having given ab-
ftrafts of what has been offered to the world by fo
many refpeftable writers on the fubjeft.
The few hints which we have thrown out will be fuf-
ficient to fhow, in general, in what manner we wilh the
youth’s education to be condufted during this period.
Let the parent and the tutor bear in mind, that much
depends on their example, with regard to the difpofi-
tions and manners of the youth -, and let them careful*
ly ftrive to form him to gentlenefs, to firmnefs, to pa¬
tient induftry, and to vigorous couragelet them, if
poftible, keep him at a diftance from that contagion
with which the evil example of worthlefs fervants and
playfellows will be likely to infeft him. Now is the
time for fowing the feeds of piety and virtue : if care¬
fully fown now, they will fcarce fail to grow up, and
bear fruit in future life.
III. From ?liberty to Manhoods
ft)
This age is every way a very important period in
human life. Whether we confider the change which
now takes place in the bodily conrtitution, or the
paflion which now firft begins to agitate the breaft,
ftill we muft regard this as a critical feafon to the
youth. The bufmefs of thofe to whofe care he is
ftill intrufted, is to watch over him fo as to prevent
the paflion for the fex from hurrying him to {hameful
and vicious indulgence, and from feducing him to ha¬
bits of frivolity and indolence j to prevent him from
becoming either the fhamelefs rake, or the trifling
coxcomb. Though fo furious is the impulfe of that
appetite which now fires the bofom and {hoots through
the veins of the youth, that to reftrain him from the
excefies to which it leads can be no eafy talk 3 yet if
his education has been hitherto condufted with pru¬
dence, if he is fond of manly exercifes, aftive, fober,
and
E D U [S63] E D U
Edncatian. and temperate, and ftill influenced by modefty and
the fenfe of flvame j even this may through the blef-
fmg of heaven be accompliflied. It is impoiiible to
give better directions than thofe of Rouffeau for this
purpofe. Let the young man know his fituation y fet
before him in a ftriking light the virtue which he may
praCHfe by reftraining appetite, and the frightful fa¬
tal vices into which he may be hurried. But truft not
to precept, nor to any views which you can lay before
him, either of the difgracefulnefs and the pernicious
conlequences of vice, or of the dignity and the hap¬
py fruits of virtue. Something more mult be done.
Watch over him with the attention of an Argus j en¬
gage him in the moft aCtive and fatiguing fports.
Carefully keep him at a diftance from all fuch compa¬
ny, and fuch books, as may fuggeft to his mind ideas of
love, and of the gratification at which it aims. But ftill
all your precautions wall not counteract the defigns of
nature ; nor do you wifh to oppofe her defigns. The
youth under your care muft feel the impulfe of defire,
and become fufceptible of love. Let him then fix his
affeClions on fome virtuous young woman. His attach¬
ment, to her will raife him above debauchery, and teach
him to defpife brutal pleafures: it wall operate as a mo¬
tive to difpofe him to apply to fuch arts, and to purfue
fuch branches of knowledge, as may be neceffary for his
future eftablhhment in the wmrld. The good fenfe of
Rouffeau on this head renders it lefs neceffary for us
to enlarge on it j efpecially as w e are to treat of fome
articles feparately which regard the management of
youth at this period.
IV. Religion and Morals.
€0
At what
age the
principles
of religion
may be
taught.
/
In pointing out the general plan of education which
appears to us the moft proper to be purfued in order
to form a virtuous and refpeCtable member of fociety,
we took but flight notice of the important objeCts of
religion and morals. At w'hat period and in what
manner, ought the principles of religion and morality
to be inftilled into the youthful mind It has been
before obferved, that children are capable of reafon-
ing and of moral diftinCtions even at a very early age.
But they cannot then comprehend our reafonings, nor
enter into our moral diftinClions •, becaufe they are
ftrangers to our language, and to the artificial manner
in which we arrange our ideas when wre exprefs them
in converfation or in writing. It follows, then, that as
foon as they are fufficiently acquainted tvith our lan¬
guage, it muft be proper to communicate to them the
principles and precepts of morality and religion. Long
before this time, they are diligent and accurate obfer-
vers of human a&ions. For a Ihort period it is merely
the external aft which they attend to and obferve :
foon, however, they penetrate farther y confcious them-
felves of reflection aud volition, they regard us alfo as
thinking beings y confcious of benevolent and of un¬
friendly difpofitions, they regard us as afting with de-
fign, and as influenced by paflion : naturally imitative
animals, they are difpofed in their conduft to follow
the example which w^e fet before them. By our ex¬
ample we may teach them piety and virtue long be¬
fore it can be proper to oiler them religious or moral
jnftruftion in a formal manner.
We cannot prefume to determine at what particular
2
period children ought to be firft informed of their re- Education..
lations to God aud to fociety, and of the duties incum-' 1 v ~
bent on them in confequence of thofe relations. That
period wall be different to different children, according
to the pains which have been taken, and the means
wdiich have been employed, in cultivating their natural
powers. Perhaps even where the moft judicious maxims
of education have been adopted, and have been purfued
wTith the happieft effefls, it cannot be fooner than the
age of eight or nine. But even before this period
much may be done. Show the child your reverence
for religion and virtue y talk in his prefence, and in
the plaineft, fimpleft terms, though not direflly to
him, of the exiftence of God the creator, the preferver
and the governor of the world ; fpeak of the conftant
dependance of every creature on the gracious care of
that Being; mention with ardour the gratitude and o-
bedience which we owe to him as our great parent and
belt btenefaftor 5 next, fpeak of the mutual relations
of fociety y of the duties of children and parents, of
mafters and fervants, of man to man. At length, when
his mind is prepared by fuch difeourfes which have paf-
fed in his prefence without being addreffed to him,
you may begin to explain to him in a direft manner
the leading do&rines of religion. He will now be able
to Comprehend you, when you addrefs him on that
important fubjecl ■: the truths which you communicate
will make a powerful impreflion on his mind 5 an im-
preflion which neither the corruption and diflipation of
the world, nor the force of appetite and paflion, will
ever be able to efface.
Some writers on this fubjecl have afferted, that Habit
youth are incapable of any juft ideas of religion till
they attain a much more advanced age y and have in¬
filled, that, for this .reafon, no attempts Ihould be
made to Communicate to them the articles of our creed
in their earlier years. This doftrine, both from its
novelty and from its pernicious tendency, has provoked
the keeneft oppofition. It has, however, been oppo-
fed rather with keennefs than with acutenefs or Ikill.
Its opponents feem to have generally allowed that
children are incapable of reafoning and of moral di-
ftin&ions y but they have aferibed wonderful effedls to
habit. Enrich the memories of children, fay they,
with the maxims of morality, and with the do&rines-
of religion y teach them prayers, and call them to en¬
gage in all the ordinances of religion. What though
they comprehend not the meaning of what they learn ?
What though they underftand not for what purpofe
you bid them repeat their prayers, nor why you con¬
fine them on the Lord’s day from their ordinary a-
mufements ? Their pow’ers will at length ripen, and
they will then fee in what they have been employed,
and derive the higheft advantage from the irkfome
talks to which you confined them. You have formed
them to habits w'hich they will not be able to lay alide;
After this they cannot but be religious at fome period
of life, even though you have infpired them with a
difguft for the exercifes of religion. Thofe good
people have alfo talked of the principle of the aj/bcia-
tion of ideas. As no man Hands alone in fociety, fay
they y fo no one idea exifts in the mind fingle and
unconnefted with others: as you are connected with
your parents, your children, your friends, your coun¬
trymen 5 fo the idea of a tree, for inftance, is connect¬
ed
E D U
t 569 ]
E D U
Education, ed v.'itli that of the field in which it grows, or the
  v   fruit which it bears, and of contiguous, diiiimilar, and
refembling objefts. When any one fet of related
ideas have been often prefented to the mind in con¬
nexion with one another, the mind at length comes to
view them as fo intimately united, that any particular
one among them never fails to introduce the reft.
Revifit the fcenes in which you fpent your earlieft
years; the fports and companions of your youth na¬
turally arife to your recolleftion. Have you applied
to the ftudy of the claflics with reluftance and con-
ftraint, and fuffered much from the feverity of parents
and tutors for your indifference to Greek and Latin j
you will, perhaps, never through the courfe of life fee
a grammar fchool, without recollecting your fufferings,
nor look on a Virgil or Homer without remembering
the ftripes and confinement which they once occafion-
ed to you. In the fame manner, when religious prin¬
ciples are impreffed on the mind in infancy in a proper
manner, a happy affociation is formed which cannot
fail to give them a powerful influence on the fentiments
and conduct in a future life. But if we have advanced
to manhood before being informed of the exiftence of
a Deity, and of our relation to him j the principles of
religion, when communicated, no longer produce the
fame happy effects: the heart and the underftanding
are no longer in the fame ftate j nor will the fame af-
fociations be formed.
This dodtrine of the affbciation of ideas has been ad¬
duced by an ingenious writer, diftinguilhed for his
difcoveries in natural philofophy, and for his labours
fociationVf controverfal divinity, as an argument in behalf of
the propriety of inftrudting youth in the principles of
religion even in their earlieft years. We admire, we
efteem, the fpirit which has prompted him to difcover
fo much concern for the interefts of the rifing genera¬
tion •, but at the fame time we will not conceal our
opinion, that even this argument ought to be urged
with caution. Many of the phenomena of human na¬
ture may indeed be explained, if we have recourfe to
the principle of affociation. The influence of any
principle, religious or moral, depends in a great mea-
fure on the ideas and images which, in confidering it,
wre have been accuftomed to affociate with it in our
minds. But what are the ideas or images moft likely
to be affociated by children with the doctrines and du¬
ties of religion, if w’e call them to liften to the one
and perform the other at too early a period ? Will
they be fuch as may aflift the influence of religion on
their fentiments and conduct in the future part of
life ? Obferve the world: Are thofe who, in infancy,
have been moft rigidly compelled to get their cate-
chifms by rote, either the moft pious or the beft in¬
formed in religious matters ? Indeed, when we confi-
der what has been faid of the influence of habit, and
of the affociation of ideas, wre cannot help thinking,
that any arguments which on the prefent occafion
May be adduced from' either of thefe, tend direftly to
prove, not that we ought to pour in religious inftruc-
tion into the minds of children, without confidering
whether they be qualified to receive it } but, on the
contrary, that wre ought cautioufly to wait for and
catch the proper feafon •,—that feafon when the youth¬
ful mind, no longer a ftranger to our language, our
fentiments, our views of nature, or our manner of rea-
Vol. VIL Part II.
62
Dr Prieft-
ley’s opi¬
nion con-
iisas.
foning, will be able to go along with us, when we talk Education.
to him of a fupreme Being, or our condition as depen- "y—T "'
dant and accountable creatures, of truth, benevolence,
and juftice.
We flatter ourfelves, then, that our readers will rea¬
dily agree with us, ift, That the moral and reafoning
powders of children begin to difplay themfelves at a
very early age, even in infancy, idly, That as loon
as they have made themfelves acquainted with the moft
obvious appearances of nature, and have gained a to¬
lerable knowledge of our language and our manner ot
arranging our ideas in reafoning, we may with the
greateft propriety begin to inftrucl them in the prin¬
ciples of religion. 3dly, That the moft careful and
judicious obfervation is neceffary to enable us to di-
ftinguilh the period at which children become capable
of receiving religious inftruftion *, becaufe, if we either
attempt to communicate to them thefe important truths
too early, or defer them till towards manhood, we
may fail of accomplilhing the great end which we have
in view.
If we can be fo fortunate as to choofe the happieft
feafon for fowing the firft feeds of piety in the infant
mind, our next care will be to fow them in a proper
manner. We muft anxioufly endeavour to communi¬
cate the principles of religion and morality, fo as they
may be eafieft comprehended by the underftanding of
the learner, and may make the deepeft impreflion on
his heart. It wmuld be a matter of the greateft diffi¬
culty to give particular directions on this head. The
difcretion of the parent or tutor muft here be his
guide. We are afraid that fome of the catechifms „
commonly taught are not very happily calculated to
ferve the purpofe for wThich they are intended. Yet
we do not wilh that they ftiould be negletted while
nothing more proper is introduced in their room. In
inftrucling children in the firft principles of religion,
wTe muft beware of arraying piety in the gloomy garb,
or painting her with the forbidding features, in wffich
Ihe has been reprefented by anchorites, monks, and pu¬
ritans. No 5 let her affume a pleafing form, a cheer¬
ful drefs, and an inviting manner. Defcribe the Deity
as the atieClionate parent, the benefactor, and though
the impartial yet the merciful judge of mankind.
Exhibit to them Jefus Chrift, the generous friend and
Saviour of the pofterity of Adam, wTho with fuch en¬
chanting benevolence hath faid, “ Suft’er little children
to come unto me.” Reprefent to them his yoke as
eafy, and his burden as light. Infill not on their fay¬
ing long prayers or hearing tedious fermons. If pof-
fible, make the doClrines of religion to appear to them
as glad tidings, and its duties as the moft delightful of
talks.
V. The Languages,
Is the time ufually fpent In learning the languages
ufefully occupied ? What advantages can our Bri-
tilh youth derive from an acquaintance with the
languages and the learning of Greece and Rome ?
Would we liften to many of the fathers, the mothers,
and the polite tutors of the prefent age, they will
perfuade us, that the time- which is dedicated to
grammar-fchools, and to Virgil, Cicero, Homer, and
Demofthenes, is foolilhly thrown away } and that no
4 C advantages
E D U
Education, advantages can be gained from the fludy of claflical
' v ‘ learning. They with their children and pupils to be
Prejudices not merety Scholars : they wifh them to acquire what
agamft claf-rnay be ufeful and ornamental when they come to min-
fical eauca- gle wuth the world; and for this purpofe, they think it
non. much better to teach their young people to fmatter.
out French, to dance, to fence, to appear in company
with invincible affurance, and to drefs in fuch a manner
as may attract the attention of the ladies. Befides, the
tendernefs and humanity of thofe people are amazing.
They are fhocked at the idea of the fafferings which
boys undergo in the courfe of a claflical education.
The confinement, the ftripes, the harfli language, the
burdens laid on the memory, and the pain occafloned
to the eyes, during the dreary period fpent in acquiring
a knowdedge of Greek and Latin, affeft them with
horror when they think of them as infilled on chil¬
dren. They therefore give the preference to a plan of
education in which lefs intenfe application is required
gj. and lefs feverity employed.
Prejudices But, again, there are others who are no lefs warm
font. in their eulogiums on a claflxcal education, and no lefs
induftrious in recommending the fludy of Greek and
Latin, than thofe are eager in their endeavours to
draw neglect on the poliflred languages of antiquity.
With this fecond clafs, if an adept in Greek and La¬
tin, you are a great and learned man j but without
thofe languages, contemptible for ignorance. They
think it impoflible to infpire the youthful mind with
generous or virtuous fentiments, to teach the boy wif-
dom, or to animate him with courage, without the af-
flflance of the ancient philofophers, hiftorians, and
poets. Indeed their fuperftitious reverence for the an¬
cient languages, and for thofe writers whofe compofl-
tions have rendered Greece and Rome fo illuflrious,
leads them to afcribe many other ftill more wonderful
virtues to a claflical education.
With which of thefe parties fhall we join ? or fhall
we mediate between them ? Is it improper to call youth
to the ftudy of the languages ? Is it impoflible to com¬
municate any ufeful knowledge without them ? Or are
they, though highly ufeful, yet not always indifpenfably
^ neceffary ?
Utility of ^ e have formerly taken notice of one circumftance
claffical in favour of a claflical education, to which it may be
Jearnin# to- proper to recal the attention of our readers. We ob-
wards the the cultivation of clafiical learning has a
ment°of favourable influence on the living languages. It has
our mother a tendency to preferve their purity from being debaf-
longue. ed, and their analogy from becoming irregular. In
fludying the dead languages, we find it neceflary to
pay more attention to the principles of grammar than
in acquiring our mother tongue. We learn our native
language without attending much to its analogy and
ftructure. Of the numbers who fpeak Englilh through
the Britifli dominions, but few are fldlied in the in¬
flexion of its nouns and verbs, or able to diftinguiflr
between adverbs and conjunctions. Defirous only of
making their meaning underflood, they are not anxi¬
ous about purity or correXnefs of fpeech. They re-
jeX not an expreflion which occurs to them, becaufe
it is barbarous or ungrammatical. As they grew up
they learned to fpeak from their mothers, their nurfes,
and others about them , they were foon able to make
known their wants, their wiflies, and their obferva-
E D U
tions, in words. Satisfied with this, or called at a Education.
vary early period to a life of humble induftry, they '-—“v 1
have continued to exprefs themfelves in their mother
tongue without acquiring any accurate knowledge of
its general principles. If thefe people find occafion
to exprefs themfelves in writing, they are fcarce more
fludicus of ccrreXnefs and elegance in writing than in
fpeaking ; or, though they may afpire after thofe
properties, yet they can never attain them. But fuch
writers or fpeakers can never refine any language,
or reduce it to a regular analogy. Neither can they
be expeXed to diftinguifh themleives as the guardians
of the purity and regularity of their native tongue, if
it Ihould before have attained a high degree of per
feXion. But they who, in learning a language dif¬
ferent from their native tongue, have found it necef¬
fary to pay particular attention to the principles of
grammar, afterwards apply the knowfledge of grammar
wfliich they have thus acquired in ufing their mother
tongue ; and by that means become better acquainted
with its ftruXure, and learn to wrrite and fpeak it with
more correXnefs and propriety. Befides, the lan¬
guages of Greece and Rome are fo highly diftinguifh-
ed for their copioufnefs, their regular analogy, and
for various other excellencies, which render them fu-
perior to even the chief of modern languages, that the
fludy of them has a natural tendency to improve and
enrich modern languages. If we look backwards to
the 15th century, when learning began to revive in
Europe, and that fpecies of learning which began firft
to be cultivated wras claflical literature, we find that
almoft all the languages then fpoken in Europe wTere
wretchedly poor and barbarous. Knowledge could not
be communicated, nor bufinefs tranfaX:ed, without
calling in the aid of Latin. Claflical learning, how¬
ever, foon came to be cultivated by all ranks with en-
thufiaftic eagernefs. Not only thofe defigned to pur-
fue a learned profeflion, and men of fortune whole ob-
jeX was a liberal education without a view to any par¬
ticular profeflion ; but even the lowTer ranks, and the
female fex, keenly ftudied the languages and the wif-
dom of Greece and Rome. This avidity for claflical
learning wras followed by many happy effeXs. But its
influence w as chiefly remarkable in producing an ama ¬
zing change on the form of the living languages. Thefe
foon became more copious and regular j and many of
them have confequently attained fuch perfeXion, that
the poet, the hiftorian, and the philofopher, can clothe
their thoughts in them to the greatefl advantage.
Could w’e derive no new advantage from the ftudy of
the ancient languages, yet would they be worthy of
our care, as having contributed fo much to raife the
modern languages to their prefent improved ft ate. But
they can alfo conduce to the prefervation and fupport
of thofe noble ftruXures wrhich have been reared by
their afllftance. The intercourfe of nations, the affec¬
tation of w riters, the gradual introduXion of provin¬
cial barbarifms, and various other caufes, have a ten¬
dency to corrupt and debafe even the nobleft languages.
By fuch means were the languages of Greece 'and
Rome gradually corrupted, till the language uled by a
Horace, a Livy, a Xenophon, and a Menander, w^as
loft in a jargon unfit for the purpofes of compofition.
But if we would not difdain to take advantage of
them, the claflical works in thofe languages might
prevent
[ 570 1
E D U [57
Education, prevent that which we ufe from experiencing inch a
1 v—' decline. He who knows and admires the excellencies
of the ancient languages, and the beauties of thole
writers who have rendered them fo celebrated, will be
the firm enemy of barbarifm, affeftation, and negli¬
gence, whenever they attempt to debale his mo. i
tongue. We venture therefore to affert, that when
the polifhed languages of antiquity ceafe to be iludied
among us, our native tongue will then lofe its purity,
regularity, and other excellencies, and gradually de¬
cline till it be no longer known for the language of
Pope and of Addifon; and we adduce it as an argu¬
ment in behalf of clalfical learning, that it has contri¬
buted fo much to the improvement of the living lan¬
guages, and is almolt the only means that can prevent
g them from being corrupted and debafed.
For inuring In thofe plans of education of which the lludy of
to induftry. the dead languages does not make a part, proper
means are feldom adopted for imprelTing the youthful
mind with habits of ihduftry : nor do the judgment,
the memory, and the other powers of the mind, receive
equal improvement, as they pafs not through the lame
exercifes as in a claffical education. Let us enter thofe
academies where the way to a complete education leads
not through the thorny and rugged paths of claffical
literature } let us attend to the exercifes which the
polite teachers caufe their pupils to perform. Do
they infill on laborious induftry or intenfe application ?
No ; they can communicate knowledge .without re¬
quiring laborious ftudy. They profefs to allow their
pupils to enjoy the fweets of idlenefs, and yet render
them prodigies of learning. But are their magnificent
promifes ever fulfilled ? Do they indeed cultivate the
underftandings of the young people intrufted to their
care ? They do not : their care is never once directed
to this important objefl. To adorn them with Ihowy
and fuperficial qualities, is all that thofe gentlemen aim
at. Hence, when their pupils come to enter the world
and engage in the duties of atlive life, they appear de-
ftitute of every manly qualification. Though they have
attained the age and grown up to the fize of man¬
hood, their underftandings are ftill childifh and feeble :
they are capricious, unfteady, incapable of induftry
or fortitude, and unable to purfue any particular ob-
je£t with keen, unremitting perfeverance. That long
ieries of ftudy and regular application, which is requi-
fite in order to attain fkill in the ancient languages,
produces much happier effefts on the youthful mind.
The power of habit is univerfally felt and acknow¬
ledged. As he who is permitted to tritle away the
earlieft part of his life in idlenefs or in frivolous oc¬
cupations, can fcarce be expedled to difplay any man¬
ly or vigorous qualities when he reaches a more ma¬
ture age fo, on the contrary, he whofe earlier days
have been employed in exercifing his memory and fur-
nifiiing it with valuable treafures, in cultivating his
judgment and reafoning powers by calling the one to
make frequent diftin&ions between various objects,
and the other to deduce many inferences from the
comparifon of the various objects prefented to the un-
derftanding, and alfo in ftrengthening and improving
the acutenefs of his moral powers by attending to hu¬
man actions and characters, and diftinguiihing between
them, as virtuous or vicious, as mean or glorious : he
who has thus cultivated his powers, may be naturally
]
ECU
Education.
expeCted to diftiaguiih himfelf when he comes to per¬
form his part in aCtive life, . by prudence,^ activity,
firmnefs, perfeverance, and moft of the otner noble
qualities which can adorn a human character. But in
the courfe of a claffical education, the powers of the
mind receive this cultivation; and therefore thefe happy
effeCts may be expeCted to follow from it. The repe¬
titions which are required afford improving exercife
to the memory, and ftore it with the moft valuable
treafures j the powers of the underftanding are em¬
ployed in obferving the diftinCtions between words j
in tracing words to the fubftances and qualities in na¬
ture which they are ufed to reprefent j in comparing
the words and idioms of different languages, and in
tracing the laws of their analogy and conftruChon ;
while our moral faculties are at the fame time improv¬
ed by attending to the characters which are deferib-
ed, and the events and aCtions which are related, in
thofe books which we are direCted to perufe in order
to acquire the ancient languages. We affert there¬
fore that the ftudy of the ancient languages is par¬
ticularly ufeful for improving and ftrengthening ail the
powers of the mind : and by that means, lor prepar¬
ing us to aCt our part in life in a becoming manner }
and this our readers will readily agree with us in con-
fidering as a weighty argument in behalf ol that plan
of education. . 68
But if, after all, claffical learning is ftill to be given Fund of
up, where ftiall we find the fame treafures of moraft1^
wifdom, of elegance, and of ufeful hiftorical knowledge, |-n,jW;efjge
which the celebrated writers of Greece and Rome nf-w}1jcj1 an_
ford ? Will you content yourfelf with the modern wrri-cient au.
ters of Italy, France, and England ? Or will you deign thors af.
to furvey the beauties of Homer and Virgil through
the medium of a tranflation ? No furely } let us pene¬
trate to thofe fources from which the modern writers
have derived moft of the excellencies which recommend
them to our notice ; let us difdain to be impofed upon
by the whims or the ignorance of a tranfiator.
Juvat integros accedere fontes.
Farther, claffical learning has long been cultivated
among us } and both by the ftores of knowledge which
it has conveyed to the mind, and the habits which it
has impreffed, has contributed in no fmall degree to
form many illuftrious charafters. In reviewing the
annals of our country, we will fcarce find an eminent
politician, patriot, general, or philosopher, during the
two laft centuries, who did not fpend his earlier years
in the ftudy of the claffics.
Yet though we have mentioned thefe things in fa¬
vour of claffical literature, and were we to defeend
to minute particulars might enumerate many more
facts and circumftances to recommend it ■, we mean
not to argue that it is abfolutely impoflible to be a
wife, a great, or a good man, unlefs you are {killed
in Greek and Latin. Means may, no doubt, be .a-
dopted to infpire the young mind with virtuous dif-
pofitions, to call forth the powers of the youthful un-
‘ derftanding, and to imprefs habits of induftry and yi-
.gorous perfeverance, without having recourfe to the dis¬
cipline of a grammar fchool. But we cannot help think¬
ing, for the reafons which we have ftated to our read¬
ers, that a claffical education is the moft likely to pro¬
duce thefe happy effects.
4 C 2 • ’As
E D CJ [ 572
are afterwards to take particular notice of
69
Duties of
people of
rank.
Education. As we
the courfe of education moft fuitable for thofe who
are to occupy the humble ftations in fociety, wre fliall
not here inquire whether it be proper to introduce them
to an acquaintance with the Greek and Latin claffics.
VI. 0/2 t/ie Education of People of Rank and Fortune.
Those whom the kindnefs of providence has placed
in an elevated ftation, and in affluent circumflances,
io that they leem to be born rather to the enjoyment
of wealth and honours than to aft in any particular
profeffion or employment, have notwithftanding a cer¬
tain part affigned them to perform, and many import¬
ant duties to fulfil. 1 hey are members of fociety,
and enjoy the proteftion of the civil inftitutions of
that fociety to which they belong; they mull there¬
fore contribute what they can to the fupport of thofe
inftitutions. Lhe labours of the mduftrious poor are
neceffary to fupply them with the luxuries of life ;
and they muft 'know how to diftribute their wealth
■with prudence and generofity among the poor. They
enjoy much leifure 5 and they ought to know how to
employ their leifure hours in an innocent and agreeable
manner. Befides, as their circumftances enable them
to attraft the regard and refpeft of thofe who are pla¬
ced in inferior ftations, and as the poor are ever ready
to imitate the conduft of their fupenors ^ it is neceffary
ti^at they endeavour to adorn their wrealth and honours
by the moll eminent virtues, in order that their example
may have a happy influence on the manners of the
community.
_ Their education ought therefore to be condufted
with a view to thele ends. After What we have urged
in favour of a claflical education, our readers will na¬
turally prefume that we regard it as highly proper for
a man of fortune. The youth who is dellined to the
enjoyment of wealth and honours, cannot fpend his
earlier years more advantageoufly than in gaining an
acquaintance with the elegant remains of antiquity.
Tne benefits to be derived from claflical learning are
particularly neceffary to him. Care mull be taken to
preferve him from acquiring a haughty, fierce, im¬
perious temper. The attention ufualiy paid to the
children of people cf fortune, and the fooliffl fondnefs
with which they are too often treated, have a direft
tendency to infpire them with high notions of their
own. importance, and to render them paflionate, over¬
bearing, and conceited. But if their temper acquire
that bias even in childhood, wrhat may be expefted
when they advance tmvards manhood, when their at¬
tention is likely to be oftener turned to the dignity
und importance of that rank which they occupy, and
to the pitiful humility of thofe beneath them ? Why,
they are likely to be fo proud, infolent, refentfiil,
and revengeful, as to render themfelves difagreeable and
hateful to all who know them : and befides, to be in¬
capable of thofe delightful feelings which attend hu¬
mane, benevolent, and mild difpofitions. Let the man
of fortune, therefore, as he is concerned for the future
happinefs and dignity of his child, be no lefs careful
to prevent him from being treated in fuch a manner
as to be infpired with haughtinefs, caprice, and info-
lence, than to prevent his mind from being foured by
harfli and tyrannical ufage.
70
-How to
form the
temper of
a young
man of for.
tune.
1 ECU
'1 be manly exercifes, as they are favourable to the Education.
health, the llrength, and even the morals j fo they are 1 '
highly worthy of engaging the attention of the young
gentleman. Dancing, fencing, running, horfeman-
flnp, the management of the mulket, and the motions
ot military dilcipline, are none of them unworthy of
occupying his time, at proper feafons. It is unne-
ceffary to point out the advantages which he may de¬
rive bom dancing } thele feem to be pretty general!v
undei flood. Perhaps our men of fortune wrould be
alhamed to make ufe of their legs for running j but
occafions may occur, on which even this humble ac-
complilhment may be ufeful. Though we wilh not to
fee the young man of fortune become a jockey 5 yet
to be able to make a graceful appearance on horfe-
back, and to manage his horfe with dexterity, will
not be unworthy of his ftation and charafter. If times
of public danger fliould arife, and the ftate ihould call
for the fervices of her fubjefts againft any hoftile at¬
tack, they whofe rank and fortune place them in the
moil eminent ilations will be firfl expefted to fland
forth ; but if unacquainted with thofe exercifes which
are connefted with the military art, what a pitiful
figure mull they make in the camp, or on the field of
battle ?
As the man of fortune may perhaps enjoy by he-
reditary right, or may be called by the voice of his aW'
fellow citizens, to a feat among the legiilative body of
his country-, he ought in his youth'to be carefully
inftrufted in the principles of her political conftitution,
and of thofe laws by which his own rights and the
rights of his fellow citizens are determined and fe-
cured.
Natural philofophy, as being both highly ufeful and philofophy ,
entertaining, is well worthy of the attention of all
who can afford to appropriate *ny part of their time
to fcientific purfuits 5 to the man of fortune, a tafle for
natural philofophy might often procure the moll de¬
lightful entertainment. To trace the wonders of the
planetary fyilems, to mark the procefs of vegetation,
to examine all the properties of that fine element which
we breathe, to trace the laws by which all the different
elements are confined to their proper funftions, and
above all to apply the principles of natural philofophy
in the cultivation of the ground, are amufements wfflich
might agreeably and innocently occupy many of the
leifure hours of the man who enjoys a fplendid and in¬
dependent fortune.
Neither do we fuppofe civil hiftory and the prin-p.^3
ciples of morals to be overlooked. Without being ac- morals ^
quainted with thele, how could any juft or accurate
knowledge of the laws and political conflitution of his
country be acquired by the young gentleman ? Hiftory
expofes to our obfervation the fortune and the aftions
of other human beings, and thus fupplies in fome mea-
fure the place of experience 3 it teaches prudence,
and affords exercife to the moral fenfe. When hiftory
c'ondefcends to take notice of individuals, they are al-
moll always fuch as have been eminent for virtue, for
abilities, or for the rank which they held in life 3 to
the rich and great it ought to fpeak with peculiar effi.
cacy, and they ought to be carefully invited to liften
to its voice.
Such then is the manner in which we wifh the edu¬
cation of young men of rank and fortune to be con¬
ducted,.
E D U
C 57.3 ]
E D U
Education, ducted, in order that they may be prepared for en-
i '“-v * ' ioyine their opulence and honours with becoming di¬
nky. Let them be early inured to habits of vigorous
induftry and perfevering firmnefs, by pari mg tarough a
regular courfe of claflical learning in a free Drool} L t
them play and converie with tneir ecjuals, and not be
permitted to form high ideas of their omr importance,
nor to domineer over fervants or inferiors: Let them
be carefully inftruefed in the principles of morality and
religion : Let them be taught the manly exercifes: Let
them be carefully informed of the nature of the political
conftitution of their country, and of the extent of thole
civil and political rights which it fecures to them and
their fellow citizens : Let them be called to trace the
annals of mankind through the records of hiftory *, to
mark the appearances and operations of nature, and to
amufe themlelves by purfuing tliele to tneir general
caufes. We fay nothing of caufing the young man of
fortune to learn fome mechanical art : VV e think Ikill
in a mechanical art might now and then alfoid him an
innocent and pleafmg amufement •, but we do not con-
fider it as abfolutely neceffary, and therefore do not in¬
fill on his acquiring it. With thole accomplilhments
we hope he might become an ufeful member of fociet\,
might adorn the rank and fortune to which he is born,
and might find wealth and high ilation a blefling, not
a curfe. It is peculiarly unfortunate for our age and
country, that people of rank and fortune are not fo
ftudious that their children acquire thefe as the more
fuperficial accomplifhments.
VII. On the Education of People defgned for a Mercan¬
tile Employment, and for the humbler Occupations in
Life not particularly conneSled with Literature.
Were modern literature in a lefs flourilhing Hate ■,
were the Englilh and French languages adorned with
fewer eminent poetical, hillorical, and philofophical
compofitions ; we might perhaps infill on it as ne-
celfary to give the boy, who is defigned for a mercan¬
tile employment, a claffical education. At prefent
this does not appear abfolutely necellary ; yet we do
Elegl* li- not prefame to forbid it as improper. Even the
terature. merchant will fcarce find reafon to repent his hav¬
ing been introduced to the acquaintance of Plato
and Cicero. But Hill, if the circumltances of the
parent, or any other juft reafon, Ihould render it
inconvenient, to fend the young man who is intend¬
ed for trade to a free fchool to itudy the ancient
languages, means may be eafily adopted to make up
for his lofs. Confine him not to writing and accounts
alone. Thefe, though particularly ufeful to the mer¬
chant, have no great power to rellrain the force of
evil paffions, or to infpire the mind with generous and
virtuous fentiments. Though you burden him not
with Latin and Greek, yet flrive to infpire him with
a take for ufeful knowledge and for elegant literature.
Some of the purefl and moll elegant of our poets, the
excellent periodical works which have appeared in our
language, fuch as the Speflator, the Adventurer, the
Mirror, and the compofitions of our Britilh hiftorians,
together with fome of the bell tranllations of the daf¬
fies which we polfefs •, thefe you may with great pro¬
priety put into his hands. They will teach him how
to think and reafon jullly, and to exprefs himfelf in Education.
converlation or in writing with corre&nefs and ele-
gance : tney will refine and polilh his mind, and raife
him above low and grofs piealures. And as no man,
who has any occafion to fpeak or write, ought to be
entirely ignorant of the principles of grammar, you will
therefore be careful to inltrudl the young man who is
defigned for a mercantile occupation in the grammar of
his mother tongue. 75
A facred regard to his engagements, and an honefty luteg ity,
which may prevent him from taking undue advantages
or exacting unreafonable profits, are the virtues which
a merchant is moil frequently called to exercife : punc¬
tuality and integrity are the duties .molt particularly
incumbent on the mercantile profellion. lemptations
will now and then arife to feduce the merchant to the
violation of thefe. But if fuperior to every fuch temp¬
tation, he is one of the moll illuilrious charafters, and
is likely .to be one of the moil fuccefsful merchants.
From his earlielt years, then, labour to infpire the
child whom you intend for trade with a facred regard
for truth and juitice : let him be taught to view deceit
and fraud, and the violation of a promile, with abhor¬
rence and difdain. Frugality is a virtue which, in the
prefent age, feems to be antiquated or proferibed. Even
the merchant often appears better Ikilled in the arts of
profufion than in thofe of parfimony. The mifer, a.
charadter at no time viewed as amiable, is at prefent be¬
held with double detellation and contempt. Yet, not-
withllanding thefe unfavourable circumftances, fear not
to imprefs upon the young merchant habits of frugality.
Let him know' the folly of beginning to fpend a for¬
tune before he have acquired it. Let him be taught to
regard a regular attention to confine his expences with¬
in due bounds, as one of the firlt virtues which can
adorn his charadler.
Frugality and indullry are fo clofely connected, that induftry,
when we recommend the one of them to the merchant,
we will be naturally underllood to recommend the other
alfo. It is eafy to fee, that without indullripus appli¬
cation, no man can reafonably expedl to meet with fuc-
ceis in the occupation in which he engages •, and if the
merchant thinks proper to leave his bulinefs to the ma¬
nagement of clerks and Ihop-keepers, it is not very pro¬
bable that he will quickly accumulate a fortune. It is,
therefore, no lefs neceffary, that he who is intended for
trade be early accuftomed to habits of fober application,
and be carefully reftrained from volatility and levity,
than that he be inftructed in writing, arithmetic, and
keeping of accounts.
With thefe virtues and qualifications the merchant is
likely to be refpeftable, and not unfuccefsful, while he
continues to profecutehis trade : and if, by the bleihng
of Providence, he be at length enabled to accumulate a
moderate fortune, his acquaintance with elegant litera¬
ture, and the various habits which he has acquired,
will enable him to enjoy it with tafte and dignity. In¬
deed, all the advantages which a man wdthout taile, or
knowdedge, or virtue, can derive from the poffeflion of
even the moil fplendid fortune, are fo inconfiderable,
. that they can be no adequate rewrard for the toil which
he undergoes, and the mean arts which he praflifes in
acquiring it. At the head of a great fortune a fool can
only make himfelf more ridiculous, and a man of a.
V
E D U
E DU [ 574 ]
Education, wicked and \dcious charadler more generally abhorred, Education
' v than if fortune had kindly concealed their crimes and VIII. On the Education of the Female Sex. —“
yy -follies by placing them in a more obfcure hat ion.
Education A confiderable part of the members of fociety are The abftrafts which we have given of fome of the
in'the Tow P*acec* circumftances, that it is impoflible for molt celebrated and original treatifes on education, as
eft ranks. * t^em to receive the advantages of a liberal education, well as our own obfervations on this lubje£t, have been
ihe mechanic and the hufbandman, who earn a fubfifi- hitherto either relative to the education of both the fexes,
ence by their daily labour, can feldom afford, whatever or directed chiefly to the education of the male fex.
parental fondnefs may fuggeft, to favour their children But as there is a natural difference between the charac-
with many opportunities of literary inftrucHon. Con- ters of the two fexes, and as there are certain duties pa¬
tent if they can provide them with food and raiment culiar to each of them 5 it is eafy to fee that the educa-
till fuch time as they acquire fufficient ftrength to la- tion of the boy and that of the girl cannot, ought not,
hour for their own fupport, parents in thofe humble to be conduced precifely in the fame manner. And
circumftances feldom think it neceffary that they Ihould
concern themfelves about giving their children learning.
Happily it is not requilite that thofe who are deftined
to fpend their days in this low fphere fliould be furnilh-
ed with much literary or fcientific knowledge. They
may be taught to read their mother tongue, to write,
and to perform fome of the moft common and the moft
generally ufeful operations of arithmetic : for without
an acquaintance with the art of reading, it will fcarce
be poffible for them to acquire any rational knowledge
of the doctrines and precepts of religion, or of the du¬
ties of morality ; the invaluable volume of the facred
Scriptures would be fealed to them : we may allow
them to write, in order that they may be enabled to
enjoy the fweet fatisfaftion of communicating accounts
of their welfare to their abfent friends 5 and, befides,
both writing and arithmetic are neceflary for the ac-
complifliment of thofe little tranfaflions which pafs
among them. It would be hard, if even the lowefl: and
pooreff were denied thefe Ample and eaflly acquired
branches of education ; and happily that degree of Ikill
in them which is neceffary for the labourer and the me¬
chanic may be attained without greater expence than
may be afforded by parents in the meanefl: circumftan¬
ces. Let the youth who is bom to pafs his days in
this humble ftation be carefully taught to conflder hon-
eft patient induftry as one of the Arft of virtues : let
him be taught to regard the fluggard as one of the moft
contemptible of charafters : teach him contentment
with his lot, by letting him know that wealth and ho¬
nour feldom confer fuperior happinefs : Yet fcruple not
to inform him, that if he can raife himfelf above the
humble condition to which he was born, by honeft arts,
by abilities virtuoufly exerted, he may And fome com¬
fort in affluent circumftances, and may And reafon to
rejoice that he has been virtuous, induftrious, and aiftive.
In teaching him the principles of religion, be careful
to fhow him religion as intimately connefted with mo¬
rality : teach him none of thofe myfterious doctrines,
whofe foie tendency is to fofter that enthuAafm which
naturally prevails among the vulgar, and to perfuade
them that they may be pious without being virtuous.
Labour to infpire him with an invincible abhorrence
tor lying, fraud, and theft. Infpire him with a high
efteem for chaftity, and with an awful regard to the
duties of a fon, a hufband, and a father. Thus may he
become refpeilable and happy, even in his humble fta¬
tion and indigent circumftances 5 a character inflnitely
fuperior, in the eyes of both God and man, to the rich
and great man who mifemploys his wealth and leifure
jn fhameful and vicious purfuits.
Ance the duties of the female fex are fo important to fo¬
ciety, and they form fo confiderable a part of our
fpecies, their education, therefore, merits the higheft at¬
tention.
In infancy, the infthnfts, the difpoAtions, and the
faculties of boys and girls feem to be nearly the fame.
They difcover the fame curioAty, and the fame difpo-
Ation to adlivity. For a while they are fond of the
fame fports and amufements. But by and by, when wTe
begin to make a diftin£tion in their drefs ; when the
girl begins to be more conAned to a fedentary life un¬
der her mother’s eye, while the boys are permitted to
ramble about without doors ; the diltinction between Similarity
their characters begins to be formed, and their tafte01"'he tha-
and manners begin to become different. The boy now
imitates the arts and the active amufements of his fa- ln° the^rft
ther j digs and plants a Attle garden, builds a houle in period of
miniature, Ihoots his bow, or draws his little cart j while Afo.
the girl, with no lefs emulation, imitates her mother,
knits, fews, and dreffes her doll. They are no longer
merely children j the one is now a girl, the other a
boy. This tafte for female arts, which the girl fo eaAly
and naturally acquires, has been judicioufly taken no¬
tice of by Rouffeau, as affording a happy opportunity
for inftrufting her in a very conAderable part of thofe
arts which it is proper to teach her. While the girl
is buAed in adorning her doll, ftie infenAbly becomes
expert at needle wrork, and learns how to adjuft her
own drefs in a becoming manner. And therefore, if
ftie be kindly treated, it will not be a matter of difficulty
to prevail with her to apply to thefe branches of female
education. Her mother or governefs, if capable of
managing her with mildnefs and prudence, may teach
her to read with great facility. For being already
more difpofed to fedentary application than the boy of
the fame age, the conflnement to which flie muft fub-
mit in order to learn to read vTill be lefs irkfome to
her. Some have pretended that the reafoning powTers
of girls begin to exert themfelves fooner than thofe of
boys. But, as we have already declared our opinion,
that the ueafoning powers of children of both fexes be¬
gin to difplay themfelves at a very early period 5 fo wTe
do not believe that thofe of the one fex begin to ap¬
pear or attain maturity, fooner than thofe of the other.
But the different occupations and amufements in which
wre caufe them to engage from their earlieft years, na¬
turally call forth their powers in different manners, and
perhaps caufe the one to imitate our modes of fpeaking
and behaviour fooner than the other. Hovrever, as
we v ifh both boys and girls to learn the art of reading
at a very early age, even as foon as they are capable of
any
l
E D' U t 57
Education, any ferious application j fo we wifh girls to be taught
1   1 the art of writing, arithmetic, and the principles of re¬
ligion and morals, in the fame order in which thefe are
inculcated on boys.
We need not "point out the reafons which induce us
to regard thefe as accomplifhments proper for the female
fex . they feem to be generally conlidered as hot only
fuitable, but neceffary. It is our moil important pri¬
vilege, as beings placed in a utuation different from
that of the inferior animals, that we are capaole or xe-
ligious fentiments and religious knowledge •, it there¬
fore becomes us to communicate religious inllruftion
with no lefs afliduity and care to the youth of the fe¬
male fex than to thofe of our own. Beiides, as the care
of children during their earlier years belongs in a parti¬
cular manner to the mother j (he, therefore, whom na¬
ture has dellined to the important duties of a mother,
ought to be carefully prepared for the proper difcharge
of thofe duties, by being accurately inftrutted, in her
youth, in fuch things as it will be afterwards requifite
• for her to teach her children.
Ladies have fometimes diftinguilhed fhemfelves as
prodigies of learning. Many of the moll eminent ge-
79 niufes of the French nation have been of the female fex.
Erudition, Several of our countrywomen have alfo made a refpect-
how far.be-able figure [n t]ie republic of letters. Yet we cannot
ladies!^m approve of giving girls a learned education. To ac¬
quire the accomplilhments which are more proper for
their fex, will afford fufficient employment for their
earlier years. If they be inftrufled in the grammar of
their mother tongue, and taught to read and fpeak it
•with propriety 5 be taught to write a fair hand, and
to perform with readinefs the moll ufeful operations of
arithmetic : if they be inftructed in the nature of the
duties which they owe to God, to themfelves, and. to
fociety j this will be almolt all the literary inilru&ion
necelfary for them. Yet we do not mean to forbid
them an acquaintance with the literature of their coun¬
try. The periodical writers, who have taught all the
duties of morality, the decencies of life, and the prin¬
ciples of talle, in fo elegant and plealing a manner, may
with great propriety be put into the hands of our fe¬
male pupil. Neither will we deny her the hiftorians,
the mod; popular voyages and travels, and fuch of our
Britiik poets as may be put into her hands without
corrupting her heart or inflaming her paflions. But
could our opinion or advice have fo much influence,
we would endeavour to perluade our countrymen and
countrywomen to banilh from among them the novelifls,
thofe panders of vice, with no lefs determined leverity
than that with which Plato excludes the poets from
his republic, or that with which the converts to Chri-
ifianity, mentioned in the Acts, condemned their ma¬
gical volumes to the flames. Unhappily, novels and
plays are almoft the only fpecies of reading, in which
the young people of the pre-ent age take delight j and
nothing has contributed more effeclualry to bring on that
dilfolutenefs of manners which prevails among all ranks.
But we will not difcover fo much aufterity as to ex-
prefs a wifh that the education of the female fex fhould
be confined folely to fuch things as are plain and ufe-
Omamert- ftik We forbid not thofe accomplilhments which are
al accom- merely ornamental, and the defign of which is to ren-
pliftiments. der them amiable in the eyes of the other fex. When
we cpnnder the duties for which they are deftmed by
Si E D U
nature, we find that the art of pleafing conflitutes no Education..
inconfiderable part of thefe •, and it would be wrong,
therefore, to deny them thofe arts, the end of which
is to enable them to pleafe. Let them endeavour to
acquire tafte in drefs: to drefs in a neat graceful
manner, to fuit colours to her complexion, and the fi¬
gure of her clothes to her lhape, is no fmall accom-
plifhment for a young woman. She who is rigged out
by the tafte and dexterity of her maid and her milli¬
ner, is nothing better than a doll fent abroad to public gr
places as a fample of their handywork. Dancing is[}ancing,
a favourite exercife : nay, we might almoft call it the
favourite ftudy of the fair fex : So many pleafing ima¬
ges are ailociated with the idea of dancing 5 drefs, at¬
tendance, balls, elegance and grace of motion irrefill'
ible, admiration, and courtlhip : and thefe are fo early
inculcated on the young by mothers and maids, that
we need not be furprifed if little Mifs confider her
leflbn of dancing as a matter of much more importance
than either her book or fampler. And indeed, though
the public in general feem at prefent to place too high
a value on dancing ; and though the undue eftimation
which is paid to it feems owing to that tafte for difli-
pation, and that rage for public amufements, which
naturally prevail amid fuch refinement and opulence ;
yet ftill dancing is an accompliftunent which both fexes
may cultivate with confiderable advantage. It has a
happy effeift on the figure, the air, and the carriage •,
and we know not if it be not favourable even to dig¬
nity of mind : Yet as to be even a firft-rate poet or
painter, and to value himfelf on his genius in thefe
arts, would be no real ornament in the character of a
great monarch ; fo any very fuperior {kill in dancing
mull ferve rather to difgrace than to adorn the lady or
the gentleman. There are fome arts in which, though <,
a moderate degree of Ikill may be ufeful or ornamental,
yet fuperior tafte and knowledge are rather hurtful,
as they have a tendency to feduce us from the more
important duties which we owe to ourfelves and to fo¬
ciety. Of thofe, dancing feems to be one : It is faid
of a certain Roman lady, by an eloquent hiftorian,
“ that flie was more fidlled in dancing than became a
modeft and virtuous woman.”
Mufic, alfo, is an art in which the youth of .the fe-
male fex are pretty generally inftrudled 5 and if their
voice and ear be luch as to enable them to attain any
excellence in vocal mufic, it may conduce greatly to
increafe their influence over our fex, and may afford a
pleafing and elegant amufement to their leifure hours.
The harpfichord and the fpinet are inftruments often
touched by female hands 5 nor do we prefume to for¬
bid the ladies to exercife their delicate fingers in calling
forth the enchanting founds of thefe inftruments. But
ftill, if your daughter have no voice or ear for mufic,
compel her not to apply to it.
Drawing is another accomplilhment which general- D„a.7fn -
ly enters into the plan of female education. Girls are '
ufually taught to aim at fome fcratches with a pencil:
but when they grow up, they either lay it totally alide,
or elfe apply to"it with fo much affiduity as to neglect
their more important duties. We do not confider ikill
in drawing, any more than Ikill in poetry, as an ac-
complilhment very neceffary for the ladies •, yet we agree
with Rouffeau, that as far as it can contribute to im¬
prove their tafte in drefs, it may not be improper for
them
E D U
*4
Arguments
for private
■education.
Education, them to purfue it. They may very properly be taught
to {ketch and colour flowers ^ but we do not wiih them
to foiget or lay afide this as foon as the drawing-mailer
is difmifled : let them retain it to be ufeful through life.
Though pride can never be lovely, even in the fairefl
female form j yet ought the young woman to be care¬
fully impreffed with--a due refpecf for herfelf. This will
jom with her native modeily to be the guardian of her
virtue, and to preferve her from levity and impropriety
of conduct. r r J
Such are the hints which have occurred to us on the
education proper for the female fex, as far as it ought
to be ccndudted in a manner different from that of the
male.
IX. Public and Private Education.
One queftion ufually difcufied by the writers on this
fubjedl has not hitherto engaged our attention. It is,
Whether it be moft proper to educate a young man pri¬
vately, or fend him to receive his education at a public
fchool ? 1 his queftion has been fo often agitated, and
by people enjoying opportunities of receiving all the
information which experience can furnifli on the fubjeft,
that we cannot be expelled to advance any new ar¬
gument of importance on either fide. Yet we may
flate what has been urged both on the one and the
other.
They who have confidered children as receiving their
education in the hcufe and under the eye of their parents,
and as fecluded in a great meafure from the fociety of
other children, have been fometimes led to confider this
fituation as particularly favourable for their acquiring
ufeful knowledge, and being formed to virtuous habits.
Though we reap many advantages from mingling in
facial life, yet in fociety we are alfo tainted with many
vnces to which he who paffes his life in folitary retire¬
ment is a ftranger. At whatever period of life we be¬
gin to mix with the wmrld, we ftill find that w^e have
not yet acquired fufficient ftrength to refift thofe temp¬
tations to vice with which we are there affailed. But if
we are thus ready to be infected with the contagion of
vice, even at any age, no other argument can be ne-
ceilary to fhow the propriety of confining children from
thofe dangerous fcenes in which this infedtion is fo ea-
lily caught. And whoever furveys the ftate of morals
m a public fchool with careful and candid attention,
even though it be under the management of the moft
vntuous, judicious, and afliduous teachers, will find
reafon to acknowledge, that the empire of vice is efta-
bliflied there not lefs fully than in the great world.
I\ othing, therefore, can be more negligent or inhu¬
man, than for parents to expofe their children to thofe
fedudhons which a great fchool prefents, at a time when
they are ftrongly difpofed to imitate any example fet
before them, and have not yet learned to diftinauifh
between fuch examples as are worthy of imitation,0 and
•thofe which ought to be beheld with abhorrence. Even
when under the parent’s eye, from intercourfe with
fe.wants and vifitors their native innocence is likely to
fiiffer conliderably. Yet the parent’s care will be much
mo.e hkely to preferve the manners of his child uncor¬
rupted in his own hoi’fe, than any afliduity and watch-
iulnefs of his teachers in a fchool.
I he morals and difpofttions of a child ought to be
[' 576 ]
E D U
tlm firft objedls of our concern in condudfing his edu- Education,
cation : but to initiate him in the principles of ufeful y-—'
knowdedge is alfo an important objebt •, and it will be
happy, if in a private education virtue be not only
better fecured, but knowledge alfo more readily ac¬
quired, than in a public. But this adfually happens.
TV hen oae or two boys are committed to the care of a
judicious tutor, he can watch the moft favourable fea-
fons for communicating inilruction ; he can awake cu-
riofity and command attention by the gentle arts of in-
fin uation : though he ftrive not to inflame their breads
with emulation, which leads often to envy and invete¬
rate hatred j yet he will fucceed in rendering learning
pleafing, by other means lefs likely to produce unfa¬
vourable effedfe on the temper and difpofitions of his
pupils. As his attention is not divided among a num¬
ber, he can pay more regard to the particular difpo¬
fitions and turn of mind of each of his pupils : he
can encourage him who is modeft and flow, and reprefs
the quicknefs and volatility of the other ; and he can
call forth and improve their powers, by leading them
at one time to view the fcenes of nature and the changes
which fhe fucceflively undergoes through the varying
feafons : at another, to attend to feme of the moft en°
tertaining experiments of natural philofophy 5 and again
alluring them artfully to their literary exercifes. With
thefe he may mix fome a drive games 5 and he may af-
fume fo much of the fondnefs of the parent, as to join
in them with his little pupils. Thefe are certainly cir-
cumftances favourable both to the happinefs and to the
literary improvement of youth ; but they are peculiar
to a private education. Befides, in a private educa¬
tion, as children fpend mere of their time with grown¬
up people than in public ; thofe, therefore, who re¬
ceive a domeftic education, fooner acquire our manner
of thinking, of exprefling ourfelves, and of behaving
in bur ordinary intercourfe with one another. For the
very fame reafon for which girls are often obferved to
be capable of prudence and propriety of behaviour at
an earlier age than boys, thofe boys who receive a fa¬
mily education will begin fooner to think and aft like
men, than thofe wTho pafs their earlier days in a public
feminary. And though you educate your fon at home,
there is no reafon wdiy he fliould be more accuftomed
to domineer over his inferiors, or to indulge a capri¬
cious or inhumane difpofition, than if he were brought
up among fifty boys, all of the fame age, fize, and rank,
with himfelf. He may alfo, in a private education,
exercife his limbs with the fame activity as in a public
one. He cannot indeed engage in thofe fports for
which a party of companions is neceffary ; but ftill
there are a thoufand objects which will call forth his
activity: if in the country, he will be difpofed to
filh, to climb for bird nefts, to imitate all that he fees
performed by labourers and mechanics : in fliort, he
wrill run, leap, throw and carry ftones, and keenly exert
himfelf in a variety of exercifes, which will produce
the moft favourable effebls on the powers both of his
mind and body. It may indeed be poflible for you to
oppofe the defigns of nature fo effeblually, if you take
pains for that purpofe, as to reprefs the natural aftivity
of your child or pupil, and caufe him to pine aw^ay his
time in liftlefs indolence j but you will thus do violence
to his difpofitions, as well as to thofe inftinbts w'hich
nature has for wife purpofes implanted in his breaft.
And
E D U
Education. And tlie bad confequences which may refult from this
“l11" 1 management are not to be confidered as the natural ef¬
fects of a domdtic education, but as the effefls of an
education carelefsly or imprudently conduced.
But there is another confideration which will per-
' haps be ftill more likely than any of thofe which wre
have hitherto urged, to prevail with the fond parent
to give his child a private education. As the infant
who is abandoned by its mother to the care of an hire¬
ling nurfe, naturally transfers its affe&ion from the
unnatural parent to the perfon who fupplies her room
and performs the duties incumbent upon her *, fo the
boy wdm is banifhed from a parent’s houfe at a time
when he has fcarce begun to know the relation in which
he ftands to his father and mother, brothers or lifters,
foon ceafes to regard them with that fondnefs which
he had contrafled for them from living in their com¬
pany and receiving their good offices. His refpetf,
his afteclion, and his kindnefs, are bellowed on new
objefls, perhaps on his mailer or his companions ; or
elfe his heart becomes fellilh and deftitute of every ten¬
der and generous feeling •, and when the gentle and
amiable affeflions of filial and fraternal love are thus,
as it were, torn up by the roots, every evil paffion
fprings up, with a rapid growth, to fupply their place.
The boy returns afterwards to his father’s houfe : but
he returns as a ftranger ; he is no longer capable of
regarding his parents and relations with the fame ten-
dernefs of affedlion. He is now a ftranger to that fi¬
lial love which fprings up in the breaft of the child
who is conilantly fenlible of the tender care of his pa¬
rents, and fpends his earlier years under their roof, in
Inch a manner as to appear the effedl of infiinfl rather
than of habit. Selfilh view’s are now the only bond
which attaches him to his parents and relations; and
by coming under their influence at fo early a period of
life, he is rendered for ever incapable of all the moll
amiable virtues w’hich can adorn human nature. Let
the parent, therefore, who loves his child, and willies
to obtain from him a mutual return of affection, be-
tvare of excluding him from his houfe, and devolving
the foie charge of him upon another, in his child¬
hood.
Thefe views reprefent a private education as the moll
favourable to virtue, to knowledge, and to the mutual
affedlion which ought always to unite the parent and
his child. But let us now liften to the arguments
which are ufually urged in behalf of a public educa¬
tion.
In the firft place, it has been afferted, that a public
education is much more favourable than a private to
the pupil’s improvement in knowledge, and much
more likely to infpire him with an ardour for learning.
In a private education, with wffiatever afliduity and
tendernefs you labour to render learning agreeable to
your pupil, ftill it will be but an irkfome talk. You
may confine him to his books but for a very Ihort fpace
in the courfe of the day, and allow him an alternation
of ftudy and recreation. Still, however, you will ne¬
ver be able to render his books the favourite objedls of
his attention. He will apply to them with reludlance
and carelefs indifference j even while he feems enga¬
ged on his leffon, his mind will be otherwife occupied 5
it w’ill wander to the fcenes where he purfues his diver-
lions, and to thofe objects which have attracted his de-
Vol. VU. Part II,
[ 577 ]
E D U
85
Arguments
for public
education.
fires. If the period during which you require his ap- Education.
plication be extremely Ihort ) during the firft part of '* v J
it, he will ftill be thinking of the amufements from
which you have called him, and regretting his con¬
finement j during the laft, he wall fondly anticipate
the moment when he is to be fet at liberty, and think
of new amufements. Again, iff you confine him du¬
ring a longer period, ftill more unfavourable effedls
will follow. Peeviftmefs, dullnefs, and a determined
averfion to all that bears the name of literature, w’ill
be naturally impreffed on his mind by fuch treatment.
How can it be otherwife ? Books poffefs fo few of
thofe qualities wdiich recommend any objedl to the at¬
tention of children, that they cannot be naturally a-
greeable. They have nothing to attradl and detain
the eye, the ear, or any of the fenfes *, they prelent
things with which children are unacquainted, and of
wffiich they know not the value : children cannot look
beyond the letters and wmrds, to the things which'thefe
reprefent 5 and even though they could, yet it is much
more pleafing to view fcenes and objefls as they exill
originally in nature* than to trace their images in a
faint and imperfebl reprefentation. It is vain, there¬
fore, to hope that children will be prevailed with to pay
attention to books by means of any allurements which
books can of themfelves prefent. Other means mult
be ufed; but thofe in a private education you cannot
command. In a public feminary, the fituation of
mailers wdth refpefl to their pupils is widely different.
When a number of boys meet together in the fame
fchool, each of them foon begins to feel the impulfe
of a principle wffiich enables the mailer to command
their attention without difficulty, and prompts them
to apply with cheerful ardour to talks which would
otherwife be extremely irkfome. This principle is a
generous emulation, which animates the breaft with
the delire of fuperior excellence, without infpiring en¬
vy or hatred of a competitor. When children are pru¬
dently managed in a great fchool, it is impoflible for
them not to feel its impulfe. It renders their talks
fcarce lefs agreeable than their amufements, and directs
their activity and curiofity to proper objedls. View
the fcholar at a public fchool, compoling his theme,
or turning over his dictionary j how alert ! how cheer¬
ful ! how indefatigable! He applies with all the eager-
nefs, and all the perfeverance, of a candidate for one
of the moil honourable places in the temple of fame.
Again, behold and pity that poor youth who is con¬
fined to his chamber with no companion but his tutor 5
none whole fuperiority can provoke his emulation, or
w’hoie inferiority might flatter him with thoughts of
his owm excellence, and thus move him to preferve by
indullrious application the advantages which he. has
already gained. His book is before him ; but how
languid, how liftlefs his polture! how heavy and dull
his eye ! Nothing is expreffed in his countenance but
dejedlion or indignation. Examine him concerning
his leffon; he replies wnth confufion and hefitation. Af¬
ter a few minutes obfervation, you cannot fail to be
convinced that he has fpent his time without making
any progrefs in learning; that his fpirits are now broken,
his natural cheerfulnefs deftroyed, and his breaft arm¬
ed with invincible prejudices againft all application in
the purfuit of literary knowledge. Befides, in a fchool
there is fomething more than emulation to render leam-
4 ^ ing
e n u [
■■■ ing lefs difagreeable than it naturally is to children.
The flighted: obfervation of life, or attention to our
own conduit in various circumilances, will be fufficient
to convince us, that whenever mankind are placed in
circumltances of diltrefs, or fubjected to any difagree¬
able reftraint, that which a Angle perfon bears with
impatience or dejeition will make a much lefs impref-
Aon on his mind if a number of companions be joined
with him in his differing or reftraint. It is efteemed
a piece of much greater feverity to conAne a prifoner
in a folitary cell, than where he is permitted to mix
with others in the fame uncomfortable Atuation. A
journey appears much lefs tedious to a party of travel¬
lers, than to him who beats the path alone. In the
fame manner, when a number of boys in a great fchool
are all buAed on the fame or on Amilar talks, a fpirit
of induftry and perfeverance is communicated from
one to another • over the whole circle each of them
infenAbly acquires new ardour and vigour; even though
he feel not the fpur of. emulation, yet, while all are
bufy around him, he cannot remain idle. Thefe are
fadfs obvious to the molt carelefs obferver.
Neither are public fchools fo unfavourable to the
virtue of their members as they have been reprefented
to be. If the matters are men of virtue and prudence,
careful to fet a good example before their pupils, at¬
tentive to the particular character and behaviour of
each individual among them, Arm to punilh obttinate
and incorrigible depravity, and even to expel thofe who
are more likely to injure the morals of others than to
be reclaimed themfelves, and at the fame time eager
to applaud and to encourage amiable and virtuous dif-
poAtions wherever they appear; under the govern¬
ment of fuch matters, a public fchool will not fail to
be a fchool of virtue. There will no doubt be par¬
ticular individuals among the pupils of fuch a femi-
nary, whofe morals may be corrupt and their difpoA-
tions vicious ; but this, in all probability, wall arife
from the manner in which they were managed before
entering the fchool, or from fome other circumftances,
rather than from their being fent for their education
to a public fchool. Again, at a public fchool young
people enjoy much greater advantages for preparing
them to enter the world, than they can poffibly be fa¬
voured with if brought up in a private and folitary
manner. A great fchool is a miniature reprefentation
of the world at large. The objedls wdfleh engage the
attention of boys at a fchool are different from thofe
which occupy their parents ; the view's of the boys
are lefs extenAve, and they are not yet capable of pro-
fecuting them by fo many bafe and mean arts : but, in
other refpe£Is, the two feenes and the aftors upon
them nearly refemble each other; on both you behold
contending paflions, oppoAte interefts, weaknefs, cun¬
ning, folly, and vice. He therefore who has perform¬
ed his part on the miniature feene, has rehearfed as it
were for the greater ; if he has acquitted himfelf well
on the one, he may be alfo expefted to diftinguifh him¬
felf on the other; and even he who has not diftinguifhed
himfelf at fchool, at leaft enters the world with fupe-
rior advantages when viewed in comparifon wdth him
who has fpent his earlier days in the ignorance and fo-
litude of a private and domeftic education. BeAdes,
when a number of boys meet at a public feminary of
5/8 ] E D U
education, feparated from their parents and relations ; Education.
nearly of the fame age, engaged in the feme iludies, ~ v  
and fond of the fame araufements ; they naturally con¬
trail friendfhips with one another wThich are more cor¬
dial and Ancere than any that take place between
perfons farther advanced in life. A friendfliip is often
formed between two boys at fchool w'hich continues
through life, and is productive of the happieft confe-
quences to each of them. While at fchool, they mu¬
tually affitt and encourage each other in their learning ;
and their mutual affedion renders their talks lefs bur-
denfome than they might otherwife And them. As
they advance in life, their friendihip ftill continues to
produce happy effeCls on their fentiments and conduft :
perhaps they are mutually ufeful to each other by in-
tereft or by perfonal affiftance in making their way in
the wmrld ; or wrhen they are engaged in the cares
and buttle of life, their intercourfe and correfpondence
with each other may contribute much to confole them
amid the vexations and fatigues to which they may be
expofed.
Such are the chief arguments ufually adduced in fa¬
vour of a public education. Wken we compare
them with thofe which have been urged to recom¬
mend a private education, we fliall perhaps And that
each has its peculiar advantages. A public educa¬
tion is the more favourable to the acquiAtion of
knowledge, to vigour of mind, and to the formation
of habits of induftry and fortitude. A private educa¬
tion, when judicioufly conduced, will not fail to be
peculiarly favourable to innocence and to mildnefs of
difpofltion ; and notwithftanding what has fometimes
been advanced by the advocates for a public educa¬
tion, it is furely better to keep youth at a diftance
from the fedutttions of vice till they be fufficiently
armed againft them, than to expofe them to them at an S6
age when they know not to what dangers they lead, and A medium
are wholly unable to reAft them. Were we to givebetween
implicit credit to the fpecious talk of the two par-t:ietwo’
ties, either a private or a public education would
form characters more like to angels than to thofe men
whom we ordinarily meet in the world: but they
fpeak with the ardour of enthuftafts ; and therefore wTe
mutt liften with caution both to the faCts which they
adduce, and to the inferences which they draw'. Could
we without expoAng children to the contagion of a
great town, procure for them the advantages of both
a public and a private education at the fame time, wre
would by this means probably fucceed beft in render¬
ing them both refpeftable fcholars and good men. If
wre may prefume to give our opinion freely, we wrould
advife parents never, except wrhen fome unavoidable
neceiTity of circumftances obliges them, to expel their
children from under their own roof till they be advan¬
ced beyond their boyifh years : let the mother nurfe
her own child ; let her and the father join in fuperin-
tending its education : they may then expeCI to be
rewarded, if they have aCIed their parts aright, by com¬
manding the gratitude, the affeClion, and the refpeft
of their child, while he and they continue to live to¬
gether. Let matters be fo ordered, that the boy may
refide in his father’s houfe, and at the feme time at¬
tend a public fchool : but let the girl be educated
wholly under her mother’s eye.
x. a?
Education.
8?
Travel con¬
fide red in
genet al.
E D U
X. On Travel,
Another Cjueftion which has been oiten difcuf-
fed comes here under our review. The philoiophers
of ancient Greece travelled in fearch of knowledge.
Books were then fcarce, and thofe few which were
to be obtained were no very rich treafunes of ufe-
ful information. The rhapfodies of a poet, the rude
legends of fome ill-informed and fabulous hilforian,
or the theories of fanciiul phiiolophers, were all that
they could afford. Thales, Lycurgus, Solon, Plato, tra¬
velled, feeking that knowledge among more civilized
nations which they could not find in their native coun¬
try. In the courfe of their travels, they heard the lec¬
tures of celebrated philofophers \ confulteo the prietls,
who wrere the guardians of the traditions of antiquity,
concerning the nature and origin of thole traditions }
and obferved the inftitutions of thofe nations which
were moft renowned for the wifdom of theii legiila-
ture. When they fet out to vifit foreign countries,
they leem to have propofed to themielves a certain
end •, and by keeping that end fteadily in view during
the courfe of their travels, they gained fuch improve¬
ment as to be able on their return to command the
veneration of their countrymen by means, of the know¬
ledge which they were enabled to communicate. Many
belides the philofophers of ancient Greece have tra¬
velled for improvement, and have fucceeded in their
views. But ancient hiffory does not relate to us, that
travelling was confidered by the Greeks or Romans as
neceffary to finilh the education of their young men
.of fortune before they entered the feenes of a&ive life.
It is true, after Greece became a province of the Ro¬
man empire, and the Romans began to admire the
fcience and elegance of Greece, and to cultivate Gre¬
cian literature, the young noblemen of Rome , often
repaired to Rhodes and Athens to complete their ftu-
dies under the mailers of philofophy and eloquence
“who taught in thofe cities. But they went thither
with the fame views with which our youth in modern
times are fent to free fchools and umverlities, not to
acquire knowledge by the obfervation of nature, of the
inilitutions, manners, and cultoms of nations} but mere¬
ly to hear leclures, read books, and perform exercifes.
In modern times, a few' men of reflection and expe¬
rience have now and then travelled for improvement :
but the greateft part of our travellers, for a long time,
were enthufiatic devotees who went in pilgrimage to
vifit the Ihrine or relics of fome favourite faint.; lol-
diers, wTho wTandered over the earth to deitroy its in¬
habitants *, or merchants, whole bufinefs as factors be¬
tween widely diftant countries and nations led them to
brave every danger in traverfing from one corner of the
globe to another. But fince the nations of modern
Europe have begun to emerge from rudene'fs, igno¬
rance, and fervile depreflion, they have formed one
great commonwealth, the members of which are fcarce
lefs intimately connected with each other than weie
the Hates of ancient Greece. The confequence of
this mutual connexion and dependence is, that annoit
all the nations of Europe have frequent intercourle with
one another •, and as fome of them are, and have long
been, more enlightened and refined than others, thofe na¬
tions who Lave attained the higheft degrees ot civiliza-
579 ] E D U
lion and refinement have naturally attracted tne admira- EL'
tion and homage of the reft. Their language has been
ftudied, their manners and arts have been adopted, and
even their drefs has been imitated. Other nations have
thronged to pay the homage due to their fuperior
merit, and to itudy under them as mafters. Hence
has arifen the practice which at prefent prevails among
us of fending our youth to complete their education
ky travelling, l#efore we introduce them to aCtive life,
or require them to engage in bulinefs. Formerly young
men were not fent to travel till alter they .had proceed¬
ed through the forms of a regular education, and had
at leaft attained fuch an age that they wTere no longer
to be conlidered as mere boys. But tne progrefs. ot
luxury, the defire of parents to introduce their chnd -
ren into the wrorld at an early age, that they mas
early attain to wealth and honours, and various other
caufes, have gradually introduced the practice of
fending mere boys to foreign countries, under pretence
of affording them opportunities of lhaking oft prejudices,
of ftoring their minds with truly uleful knowledge, and
of acquiring thofs graceful manners and that manly.ad-
drefs which will enable them to acquit themielv es in a
becoming manner when they are called to the duties of
abtive life. How much travelling at fuch an e.aily age
contributes to fulfil the view's of parents, a flight fur-
vey of the fenate-houfe, the gambling-houfes, the race-
courfe, and the cockpit, will readily convince the fa-
gacious obferver. _ _
But we w'iih to fofter no prejudices againft^.neigh¬
bouring nations •, w7e entertain no fuch prejuuices in
favour of Britain, as to wilh to confine our country¬
men within the fea-girt ille. Let us inquire what ad¬
vantages may be gained by travelling, and at w'hat age
it may be moft proper to fet out in purfuit of thofe
advantages.
After all that bookifti men have urged, and not-Travel ne-
withftanding all that they may continue vehemently ™
to urge, in behalf of the knowledge to be derived from tion ofH
their beloved books •, it muft ftill be acknowledged, that know’ledge,
books can teach us little more than merely the lan¬
guage of men. Or, if we Ihould grant that books are
of higher importance, and that language is the leaft:
valuable part of the knowledge which they teach, yet
ftill we need to beware that they lead us not affray j
it is better to examine nature wdth the naked eye, than
to view her through the fpedtacles of books. Neither
the theories or experiments of philofophers, nor the
narratives of travellers, nor the relations of hiftorians,
though fupported by a numerous train of authorities,
are worthy of implicit credit. T ou retire from the
world, confine yourfelf for years to your clofet, and
read volume after volume, hiftorians, philofophers, and
poets ; at laft you fancy that you have gained an im-
menfe ftore of knowledge : But leave your retirement,
return into the world, compare the knowledge which
you have treafured up with the appearances of nature, j
you will find that you have laboured in vain, that it is
only the femblance of knowledge which you have ac¬
quired, and w’ill not ferve for a faithful guide in life,
nor even enable you to diftinguilh yourfelf for literary
merit. Compare the relations of travellers with one
another *, how feldom do they agree when they deferibe
the fame feenes and the iame people ! I u-m your at¬
tention to the moft refpeclable hiftorians, compare
n
tbeir
E D U
.Education, their accounts of the fame events;     ,
v ' what contrariety ! Where (hall truth be found ? Liften
to the cool, the candid philofophers j what contradic¬
tory theories do they build on the fame fyllem of facts!
We agree, then, that it is better to feek knowledge
by aftual obfervation and experiment, than to receive
it at fecond hand from the information of others. He
who would gain an acquaintance with the beauties of
external nature, muft view them with his own eyes •
he who would know the operations of the human un-
derftanding, mull: relleft upon what paffes in his own
mind; he who would know the cuftoms, opinions,
and manners of any people, muft mingle with them,
muft obferve their conduft, and liften to their conver-
fation. The arts are acquired by aftual praftice 5 the
fciences by a final obfervation in your own perfon, and
by deducing inferences from your obfervations.
If thereiore to extend our knowledge can contri¬
bute in any degree to render us happier, wifer, or
better 5 travelling, as being more favourable to know¬
ledge than the ftudy of books, muft be highly advan¬
tageous. Get well acquainted with your own coun-
try.; with the manners, the cuftoms, the laws, and the
political fituation of your countrymen : Get alfo a
knowledge of books 5 for books would not be altoge¬
ther ulelefs, though they could ferve no other purpofe
but to teach us the language in which mankind ex-
prefs themfelves: And then, if your judgment have at¬
tained maturity 5 if curiofity prompt you 5 if your con-
ftitution be robuft and vigorous, and your fpirits live¬
ly ; you may imitate the Solons, Homers, and Platoes,
of old, and vifit foreign countries in fearch of know¬
ledge, and with a view to bring home fomething which
may be of real utility to yourfelf and your country.
You will, by this time, be fo much mafter of the lan¬
guage of your own country, that you will not lofe it
while you are learning the languages of foreign nations j
your principles of tafte and of right and wrong will
be fo formed and fixed, that you will not defpife any
mftitution or cuftom or opinion merely becaufe it pre¬
vails not in- your own country; nor yet will you be
ready to admire and adopt any thing, merely becaufe
it prevails among a foreign nation who are diftinguifti-
ed for profound and extenfive knowledge, or for ele¬
gance of tafte and manners. No ; you will divert
} ourfelf of every prejudice, and judge only by the
fixed unalterable principles which determine the di¬
ll in clion between right and wrong, between truth and
faliehood, between beauty and deformity, fublimity
and meannefs. Your objeft will not be to learn exotic
vices, to mingle in frivolous amufements, or to form
a catalogue of inns. Your views, your inquiries, will
have a very different dirediion. You will attend to
the ftate of the arts, of the fciences, of morals, man¬
ners, and government ; you will alfo contemplate with
eager delight, the grand or beautiful fcenes of nature,
and. examine the vegetable productions of the various
regions through which you pafs, as well as the different
[ 580 ] E D U
what difagreement ! other through every various legion and climate from one Education
extremity of the globe to another j you will admire —-v  
and revere that impartiality with which the Author of
nature has dillributed his benefits to the wTole human
race. When from the chilly climes and ftubborn foil
of the north, you turn your eyes to the fertile ge¬
nial regions of the louth, where every tree is loaded
with exquifite fruits, and every vegetable is nourilh-
ing and delicious 5 you will be pleafed to find, that the
inhabitants of the north, by their ftiperior ingenuity
and vigour, are able to raife themfelves to circumftances
no lefs comfortable and refpedable than thofe which
the nations inhabiting between the tropids enjoy : when
you behold the French fhaking off the yoke of def-
potjfm, and afpiring to the fweets of liberty as well as-
their Britilh neighbours: you will be pleafed to fee, that
the natural gaiety and cheerfulnefs of the former nation
render them not incapable of the energy of the latter.
You will be pleafed to view the remains of antiquity,
and the noble monuments of art; but you will think
it below you to trille away your time in gazing at pa¬
laces and churches, and collecling rufty° medals and
fragments of marble j you will feek the fociety of emi-
nent men, and eagerly cultivate an acquaintance with
the moft diftinguifhed artifts and men of fcience wdio
adorn the nations among w'hom you may happen to
fojourn.. Knowing that the knowledge which is to
be acquired in great towns, is by no means an ade¬
quate compenfation for the vicious habits which you
are liable to contra# in them 5 and befides, that the
luxuries, the arts, the manners, the virtues, and the
vices of all great towns are nearly the fame, fo that
when you have feen one, you have leen all others j you
will avoid taking up your refidence for any confider-
able time in any of the great towns through which
you have occafion to pafs in the courfe of your tra¬
vels. . The traveller who has attained the previous ac-
complirtunents which we have mentioned as neceffary,
who fets out with the views which we have fuppofed
him to entertain, and who conduits his travels in this
manner, cannot fail to return home enriched with
much ufeful knowledge •, he cannot but derive more
real improvement from travelling, than he could have
gained by {pending the fame period of time in folitary
itudy: when he returns to his native country, he will
appear among his countrymen as more than a philofo-
pher 5 a fage, and a benefactor. His knowledge is
fo extenfive and accurate, his views are fo liberal and
enlarged, and he is fo fuperior to prejudices, without
being the enemy of any ufeful eftablilhments, that he
will be enabled to command univerfal efteem, by per¬
forming his part in life with becoming dignity and pro¬
priety, and perhaps to render his name illuitrious, and
his .memory dear to future times, by fome important
fervices to the community to which he belongs, or
even to mankind in general,
. But though we have thus far, and we hope for ob- CircunL
vious .and folid reafons, decided in favour of travelling, ftances that
* r, * m /r ^  ; ? as being more likely than a folitary application torendertra-
what bkffmgs the beneficence of nature has conferred on books, to fumifh the mind with ufeful and orna-vel'ing.Vn*
the inhabitants of each.particular dmfion of the globe, mental knowledge 5 yet we do not fee that our Britifli£Ve^uth
and how far the ingenuity and induftry of man have ta- youth either take care to fumilh themfelves with the of She kef
xen. advantage of the kmdnefs of nature.. Thus fur- previous knowledge which we confider as indifpen-fent age*
*eymg the face of the earth, and confidenng.how ad- fably neceffary in order to prepare them for travelling-
•'.antages and dnaavantages are balanced with each with advantage, or fet out with proper views, or pro-
fecute
tribes of animals wdueh inhabit them 5 you will obferve
E D U
[ 58
Education, fee ate their travels in a prudent judicious . manner.
l-—v   After receiving a very imperfect education, m which
religious and moral initruition are almod wholly ne¬
glected, and no means are ufed to infpire the youth¬
ful mind with folid, virtuous, manly qualities j but
every art is tried to make the young man appear learn¬
ed, while his mind is deftitute of all ufeful information,
and to teach him to affume the confidence of manhood
before he has attained even to a moderate degree of
fenfe and prudence after an education conduced
in this manner, and with thefe views, the (tripling is
fent abroad to view7 the wmrld, and is expeCted to ic-
turn home a finiihed character, an ornament and a
comfort to his parents and all his connexions. He is
hitherto unacquainted, perhaps, even wfith the fimple
events of the hiftory of his native country 5 and either
totally ignorant of claflical literature, or but \eiy lu-
perficially inftructed in it. He has not yet viewed
with a difeermng eye the manners and cuttoms pie-
vailing among his countrymen j he knows not the na¬
ture of the government under which he lives, nor the
fpirit of thofe laws by which his civil conduCf inuft be
regulated. He has no fixed principles ; no clear, di-
ftinft views. But to fupply all his wants of this na¬
ture, he is put into the hands of a travelling governor,
-who is to be entirely fubmiffive to his will, and yet to
ferve him both for eyes and intelka. This governor
is generally either fome macaroni olheer, wrho is conli-
dered as well bred, and thougtit to know tne w orld ;
or elfe, perhaps, fome cringing fon of literature, who
having Ipent much time among his books, without
acquiring fuch ftrength or dignity of mind as to raile
him above frivolity of manners and converfation or
pitiful fawning arts, is therefore regarded as happily
qualified for this important charge. This refpeftable
perfonage and his pupil are (hipped off for France,
that land of elegant diffipation, frivolity, and fafhion.
They travel on with eager impatience, till, they reach
the capital. There the young man is induitrioufiy
introduced to all the gay feenes wdiich Pans can dii-
play. He is, at firft, confounded 5 by and by his
fenfes are fafeinated $ new defires are awaked in Ins
bread j all around him he fees the fons of diffipati.on
wallowing in debauchery, or the children of vanity
fluttering about like io many gawdy infeffs. The
poor youth has no fixed principles : he has not been
taught to regard vanity as ridiculous, or to turn from
vice with abhorrence. No attempt is made to allure
him to thofe objecls, an attention to which can alone
render travelling truly beneficial. Hitherto his mind
had been left almod wholly uncultivated j and now
the feeds of vice are plentifully fown in it. From one
great town he is conveyed to another, till he vifit al¬
mod every place in Europe where profligacy of man¬
ners has attained to any uncommon height. . In this
happy courfe of education he probably continues to
purfue improvement till he is well acquainted wfith
mod- of the pod roads, the principal inns, and the great
towns at lead in France and Italy •, and perhaps till
he has worn out his conditution, and rendered his
mind totally incapable of any generous fentiments or
fober refledtion. He then revifits his native country,
to the inexpreflible happinefs of his parents, who now
eagerly long to embrace their all-accompliftied child.
But ho.w miferably are the poor folks difappointed,
2.
r ] E D U'
when they find his conditution waded, his underdand- Education,
ing uninformed, his heart deditute of every manly or
generous fentiment : and perceive him to pofleis. no
accompliflunent, but fuch as are merely fuperficial. ?
Perhaps, however, his parents are prevented by their
partiality both for their child and for the means
which they have adopted in condudting his education,
from viewing his charadter and qualifications in a
true light. Perhaps they overlook all his defedfs, oi
confider them as ornaments, and regard their dear ion
as the mirror of perfection. But, unlo.rtunatel),
though they be blind to the hideous deformity of the
monder which they have formed, they cannot hinder
it from being confpicuous to others *, though they may
view their fon’s charadter as amiable and refpedtable,
they cannot render it ufeful, they cannot prevent it
from being hurtful to fociety. Let this youth whole
education has been thus wifely condudled, let him be
placed at the head of an opulent fortune, advanced to
a feat in the legiilative body of his country, or called
to adt in any public charadter ; how will he diffinguifli
himfelf ? As the virtuous patriot, the honed yet able
ffatefman, the Ikilful general, or the learned upright
judge ? How will he enjoy his fortune ? Will he be
the friend of the poor, the fleady fupporter .of the law s
and conditution under wrhofe protedtion he lives f Will
he (how himfelf capable of enjoying otium cum digni-
tate ? If w7e reafon by the ufual laws of probability,
we cannot expedt that he fliould; and if we obierve
the manners and principles of our men of wealth and
high birth who have been brought up in his manner,
we find our reafonings confirmed.
Such are the opinions which candid obfervation leads
us to entertain with regard to the advantages wdiich
may be gained by travelling.
He wfiiofe mind has been judicioufly cultivated, and
who has attained to maturity of judgment, if he fet out
on his travels w'ith a view7 to obtain real improvements,
and perfiff invariably in the profecution of that view7,
cannot but derive very great advantages from travel-
ling.
But again, thofe young men whofe minds have not
been previoutly cultivated by a judicious education, who
fet out without a view7 to the acquifition of real know7-
ledge, and who w7ander among foreign nations, without
attention to any thing but their luxuries, their follies,
and their vices, thofe poor young men cannot gain any
real improvement from their travels.
Our countrymen, wfiro travel for improvement, do
not appear to derive fo much advantage from their
travels as w7ere to be wfiftied, becaufe they generally re¬
ceive too fuperficial an education, fet out at too early
a period of life, and direft not their views to objefts of
real utility and importance.
XL On Knowledge of the World, and Entrance into ■
Life.
Much has been faid concerning the utility of a Unhappy
knowledge of the world, and the advantage of acqui • effedts of a
ring it at an early period of life. But thofe who have too early
the mod earneflly recommended this knowledge of the™"0™^
world, have generally explained themfelves in fo inac- tfie wory^
curate a manner concerning it, that it is difficult to
underhand what ideas they affix to it. They feem. to
wiih,_.
Education
9l
mat
knowledge
ot the
world may
be lately
communi¬
cated to
young peo¬
ple.
E D U [582
with, that, in order to acquire it, young people may
be early made acquain’ ed until all the vices and follies
of the world, introduced into polite company, carried
to public places, and not confined even from the ga¬
ming table and the flews. Some knowledge of the
world may, no doubt, be gained by thefe means. But
it is fureiy dearly purchafed; nor are the advantages
which can be derived from it fo conlidetable, as to
tempt the judicious and affeclionate parent to expofe
his child to the infection of vanity, folly, and vice, for
their fake. Carry a boy or girl into public life at the
age of fourteen or fifteen ; fhow them all the fcenes of
fplendid vanity and diffipation which adorn London or
Paris ; tell them of the importance of drefs, and of
the ceremonies of good breeding and the forms of in-
tercourfe •, teach them that fafhionable indifference and
affurance which give the ton to the manners of our fine
gentlemen and fine ladies of the prefent age. What
effecfs can you expedl the fcenes into which you intro¬
duce them, and the myfteries which you now teach
them, to produce on the minds of the children ? They
have a direft tendency to infpire them with a tafle for
vanity,' frivolity, ^and diflipation. If you wifh them to
be like the foolifh, the diflipated, and the gay, you
are likely to obtain your purpofe 5 but if, on the con¬
trary, your views are to prepare them for difcharging
the duties of life, you could not adopt more improper
means : for though they be well acquainted with all
thofe things on which you place fo much value, yet
they have not thereby gained any acceffion of ufeful
knowledge. They are not now more able than before
to eftimate the real value of objefts 5 nay, their judge¬
ment is now more liable than before to be milled in
eftimating the value of the objects around them. Lux¬
ury, vanity, and fafluon, have ftamped on many things
an ideal value. By mingling at an early age in thofe
fcenes of the world where luxury, vanity, and fafhion,
reign with arbitrary fway, young people are naturally
imprefied with all thofe prejudices which thefe have
a tendency to infpire. Inftead of acquiring an ufeful
knowledge of the wrorld, they are rendered incapable
of ever viewing the world with an unprejudiced and
difcerning eye. If pofhble, therefore, we fhould ra¬
ther labour to confine young people from mingling in
the fcenes of gay and diffipated life till after they have
attained maturity of age and judgment. They wall
then view them in a proper light, and perhaps be
happy enough to efcape the infeftious contagion of
vice.
But there is another and a more valuable knowdedge
of the world, which we ought indultrioufly to com¬
municate to them as foon as they are capable of recei¬
ving it. As foon as'they are made thoroughly acquaint¬
ed with the diliinflions between right and wrong, be¬
tween virtue and vice, between piety and impiety, and
have become capable of entering into our reafonings 5
we ought then to inform them concerning the various
eftablifihments and inftitutions which exilt in fociety j
concerning the cuftoms, opinions, and manners of man¬
kind 5 and concerning the various degrees of ftrength
or weaknefs of mind, of ingenuity or dullnefs, of vir¬
tuous or vicious qualities, which difcriminate thofe cha-
radlers which appear in fociety. We ought alfo to feize
every opportunity which may be prefented of exempli¬
fying our lefibns by inliances in real life. We mull
I
1
E D U
Edu ards.
point out to them thofe circumftances wdrich have led Edulcora-
mankind to place an undue value on fome objects, tIon
while they appretiate others much below their real uti¬
lity and importance. Thus let us fortify their judge- 1
ments againlt that impreilion wdiich the dazzling novel¬
ty of the icene, and the force of pafiion, will be apt to
produce ; and communicate to them ft knowledge of
the world, without expoling them imprudently to the
contagion of its vices and follies. '
When at length the period arrives at w'hich they
muft be emancipated from fubjeftion, and committed
to the guidance of their own conicience and reafon,
and of thofe principles which we have laboured to in¬
culcate on their minds ; let us warn them of the dan¬
gers to wdiich they are about to be expofed; tell them
of the glory and the happinefs to which they may at¬
tain ; infpire them, if polfible, with dildain for folly,
vanity, and vice, whatever dazzling or enchanting
forms they may affume ; and then dilmifs them to en¬
rich their minds wdth new idores of knowledge by vi-
fiting foreign nations; or, if that Ihould be inconveni¬
ent, to enter immediately on the duties of fome ufeful
employment in aftive life.
EliULCORATION, properly fignifies the render¬
ing iubftances more mild. Chemical edulcoration con-
fills almoft alw’ays in taking awTay acids and other fa-
line fubltances ; and this is eifefted by wafhing the bo¬
dies to which they adhere in a large quantity of water.
The walking of diaphoretic antimony, powder of al-
garoth, &c. till the water comes off quite pure and
infipid, are inltances of chemical edulcoration.— In
pharmacy, juleps, potions, and other medicines, are
faid to be edulcorated^ by adding fugar or fyrup.
EDWARD, the name of feveral kings of England.
See (Hi/Ionj of) England.
EDWARDS, George, fellow of the royal and an¬
tiquarian fccieties, was born at Stratford, a hamlet be¬
longing to Wellham in Effex, on the 3d of April 1694.
After having fpent fome time at fchool, he was put
apprentice to a tradefman in Fenchurch llreet. His
mailer, wdio wras eminent both for his piety and Hull in
the languages, treated him wdth great kindnefs j but
about the middle of his apprenticelhip, an accident
happened wdiich totally put a Hop to the hopes of
young Edwards’s advancing himfelf in the wray of trade.
Dr Nicolas, a perfon of eminence in the phyfical world,
and a relation of his mailer’s, happened to die. The
Doctor’s books were removed to an apartment occu¬
pied by Edwards, who eagerly employed all his leifure
hours, both in the day and great part of the night, in
perilling thofe which treated of natural hiilory, fculp-
ture, painting, aftronomy, and antiquities. The reading
of thefe books entirely deprived him of any inclination
for mercantile bufinefs he might have formerly had, and
he refolved to travel into foreign countries. In 1716, he
vilited moll of the principal towms in Holland, and in
about a month returned to England. Two years after,
he took a voyage to Norway, at the invitation of a
gentleman wdio was difpofed to be his friend, and who
was nephewr to the mailer of the Ihip in which he em¬
barked. At this time Charles XII. was befieging Fre-
derickfhall ; by wdiich means our young naturalill wTas
hindered from making fuch excurfions into the coun¬
try as otherwife he would have done, for the Swedes
were very careful to confine fuch llrangers as could not
give
E D W [ 583 J
Edwards, give a good account of themfelves. Eut notuxtl.iland-
 v—Jng an his precaution, he was confined i>y the Danilh
ruard, who fuppofed him to be a ipy employed by the
enemy to get intelligence of their defigns. However,
by obtaining tefiamonials of his innocence, a releafe was
granted. In 1718 he returned to England, and next
year vifited Paris by the way of Dieppe. During his
pay in this country he made two journeys of 100 miles
each 5 the firft to Chalons in Champagne, in May 1 7 20 •,
the fecond on foot, to Orleans and Jdlois 5 but an edict
happening at that time to be iflued for fecuring va-
grants, in order to tranfport them to America, as
the banks of the Mifliffippi wanted population} our au¬
thor narrowly efcaped a weftern voyage. On his ar¬
rival in England, Mb Edwards clofely purfued his fa¬
vourite ftudy of natural hiftory, applying himfelf to
drawing and colouring luch animals as fell under his
notice. A ftrift attention to natural, more than pic-
turefque beauty, claimed his earlieit caie . biids full
engaged his particular attention } and having pui-
chafed fame of Mae beft piblures of thefe lubjects, he
was induced to make a few drawings of his own j which
were admired by the curious, who encouraged our
young naturalift to proceed, by paying a good price
for his early labours. Among his firft patrons and bene-
fadtors may be mentioned James I heobalds, Efq. of
Lambeth 5 a gentleman zealous for the promotion of
fcience. Our artift, thus unexpeaedly encouraged, in-
creafed in fkill and afliduity j and procured, by his ap¬
plication to his favourite purfuit, a decent fubfiftence and
a large acquaintance. HowTever, he remitted his in-
duftry in 17315 when, in company with two of his re¬
lations, he made an excuriion to Holland and Biaoant,
where he colledled feveral fcarce books and prints, and
had an opportunity of examining the original pictures of
feveral great mafters at Antwerp, brufiels, Utrecht, and
other cities. In December 1733, by the recommenda¬
tion of the great Sir Hans Sloane, Bart, prefident of the
College of Phyficians, he was chofen librarian, and had
apartments in the college. This office was peculiarly a-
greeable to his tafte and inclination, as he had the oppoi-
tunity of a conftant recourfe to a valuable library, fill¬
ed with fcarce and curious books on the fubjedl of na¬
tural hiftory, which he fo affiduoufly fludied. By de¬
grees he became one of the moft eminent ornithologills
in this or any other country. His merit is lo wTeIl
known in this refpea, as to render any eulogium on his
performances unneceffary: but it may be obferved, that
he never trufted to others wffiat he could perform him¬
felf 5 and often found it fo difficult to give fatisfadlion
to his own mind, that he frequently made three or four
drawings to delineate the objedt in its moft lively cha-
racter, attitude, and reprefentation. In 1743, the firft
volume of the Hiftory of Birds was publifhed in quarto.
His fubfcribers exceeding even his moft fanguine expec¬
tations, a fecond volume appeared in 1747. The third
volume was publiftied in I750, *75U fourth vo¬
lume came from the prefs. This volume being the laft
he intended to publilh at that time, he feems to have
confidered it as the moft perfedt of his produdlions in
natural hiftoryand therefore devoutly oftered it up to
the great God of nature, in humble gratitude for all
the good things he had received from him in this world.
Our author, in 1738, continued his labours under a
new title, viz. Gleanings of Natural Hiftory. A fe- Edwards,
cond volume of the Gleanings was publiffied in 1760. Edvito-.e.^
'J’he third part, which made the feventh and laft volume
of his works, appeared in 1764. Thus our author, af
ter a long feries of years, the moft ftudious application,
and the moft extenfive correipondence to every quarter
of the world, concluded a work which contains engra¬
vings and defcriptions of more than 600 fubjedls in na¬
tural hiftory, not before defcribed or delineated. He
like wife added a general index in French and Engliffi ;
which was afterwards perfected, with the Lirmcean names,
by that great naturalift Linnaeus himfelf, who frequent¬
ly honoured him with his friendfhip and correfpondence.
Some time after Mr Edwards had been appointed
library keeper to the Royal College of Phyficians, he
was, on St Andrew’s day, in the year 1750, prefented
with an honorary compliment by the prefident and
council of the Royal Society, with the gold medal, the
donation of Sir Godfrey Copley, Bart, annually given
on that day to the author of any new difcovery in art
or nature, in confideration of his natural hiftory juft
then completed. A copy of this medal he had after¬
wards engraved, and placed under the title in the firft
volume of his hiftory. He w^as a few7 years afterwards
eledfted fellow of the Royal Society, and of the Society
of Antiquaries, London ; and alfo a member of many
of the academics of fciences and learning in different
parts of Europe. In compliment to thefe honorary
diftinflions from fuch learned bodies, he prefented ele¬
gant coloured copies of all his wmrks to the Royal Col¬
lege of Phyficians, the Royal Society, and Society of
Antiquarians, and to the Britiffi mufeum : alfo to the
Royal Academy of Sciences at Paris, from wffiom he re¬
ceived the moft polite and obliging letter of thanks by
their then fecretary Monfieur Defouchy. His collec¬
tion of drawings, which amounted to upwards of poo,
were purchafed by the earl of Bute. 4 hey contain a
great number of Britiffi as wrell as foreign birds, and
other animals hitherto not accurately delineated or de~
fcribed. After the publication of the laft work, being
arrived at his 70th year, he found his fight begin to fail,
and his hand loft its wonted fteadmefs. He retired from
public employment to a little houfe which he purchal
ed at Plaiftow7 5 previous to which, he difpofed of all
the copies, as well as plates, of his works. T he conver-
fation of a few7 feleft friends, and the perufal of a few
fele£I books, were the amufement of the evening of his
life; and now and then he made an excurfion to fome
of the principal cities in England, particularly to Bri-
ftol, Bath, Exeter, and Norwich. Some years before
his death, the alarming depredation of a cancer, wffiich
baffled all the efforts of medical Ikill, deprived him of
the fight of one of his eyes : he alfo fuffered much
from the ftone, to wffiich at different periods of his life
he had been fubjeft. But in the fevereft paroxyfms of
pain, he was fcarcely known to utter a fingle complaint.
Having completed his 80th year, emaciated with age
and ficknefs, he died, defervedly lamented, on the 23d
of July 1773.
EDYSTONE, a lighthoufe in the Britifir channel,
built on rocks of the fame name, which are fuppofed to
have got this appellation from the great variety of con¬
trary lets of the current among them, both upon tne tide
of flood and the tide of ebb." They are fituated nearly
fouth-
E D Y
fouth-lbuth-wefl from the middle of Plymouth found ac-
cordmg to the true meridian 5 and the diftance, as near¬
ly as can be colkaed, 1S twelve miles and a half: and from
the lame point in the Sound to the Jetty Head, called the
-Barbican, in the port of Plymouth, is a mile and a half
more, which makes the diitance of the Edyftone from
the °* Plymouth to be nearly fourteen miles,
. ^Promontory called Ram Head is the neareft
point oi land to the Edyifone, which bears from thence
louth Icarcely one point weft, diftant about ten miles,
and confequently by the compafs is nearly fouth-weft by
louth.—Thofe rocks are nearly in a line, but fomewhat
within that hue which joins the Start and the Lizard
joints j and as they lie nearly in the direction of vef-
lels coafting up and down the channel, they muft, be-
ore a lighthaufe was eftablilhed thereon, have been
very dangerous, and often fatal to Ihips under fuch cir-
cumftances: and many rich Ihips and other veffels have
m former times, been aftually loft upon thofe rocks!
particularly fuch as were homeward-bound from foreign
parts ; it being even now a common thing, in fo^gy
and thick hazy weather, for homeward-bound Ihips
from long foreign voyages to make the Edyftone light-
houle. as the. firft point of land of Great Britain • fo
that in the night, and nearly at high water, when the
whole range of thefe rocks arc covered, the moft careful
mariner might run his Ihip upon them, if nothing was
placed there by way of warnings
-The many fatal accidents which fo frequently hap¬
pened, made it a thing very defirable to have a light-
houfe built thereon, and that for many years before
any competent undertaker appeared. At length, how¬
ever, we learn, that in the year 1696 Mr Henry Win-
flanley, of Littlebury in the county of Effex, Gent,
was not only hardy enough to undertake it, but was
fumifhed with the neceflary powders to put it in execu¬
tion. This, it is fuppofed, was done in virtue of the
general powers lodged in the mafter, wardens, and affif-
>tants of the Trinity-houfe at Deptford Strond to ere&
ea marks, &c. by a ftatute of Queen Elizabeth, where¬
by they are impowered ‘ to erect and fet up beacons,
marks, and figns for the fea, needful for avoiding the
dangers; and to renew, continue, and maintain the
lame.’ But whether Mr Winftanley was a proprietor
or ftiarer of the undertaking under the Trinity-houfe,
or only the dire&ing engineer employed in the execu-’
tion, does not nowr appear.
1 gentleman had diftinguiflied himfelf in a cer¬
tain branch of mechanics, the tendency of which is to
raife wonder and furprife. He had at his houfe at Lit-
[ S84 ]
E D Y
tlebury a fet of c^ncesTfurh a7.h; foZ-W _ “Zf iffi ’’ Z dOWn 'he "PP"
Being taken into one particular room of his houfe"and L »
jj . J cid luiiuwiiig
-Being taken into one particular room of his houfe, and
there obferving an old flipper carelefsly lying on the
middle of the door,-—if, as wras natural, you gave it a
kick wuth your foot, up ftarted a ghoft before you : If
you fat down in a certain chair, a couple of arms would
immediately clafp you in, fo as to render it impoflible
to difentangle yourfelf till your attendant fet you at li¬
berty : And if you iat down in a certain arbour by thd Edyltone,
hue ot a canal, you was forthwith fent out afloat to the' 
mmdle of the canal, from whence it was impoflible for
you to efcape till the manager returned you to your
mrmer place.-—Whether thofe things were Ihewn to
itrangers at his houfe for money, or were done by way
or amufement to thofe that came to viflt the place is
uncertain 5 as Mr Winftanley is faid to have been a
man of fome property : but it is at leaft certain, that
be eftablilhed a place of public exhibition at Hyde
park comer, called IVinJlanleif s water-works; which
were Ihewn at ftated times at one Hulling each perfon.
Ine particulars of thofe water-works are not now
known 5 but according to the tafte of the times, we
mult naturally luppoie a great variety of Jets d'eau
&.c. (a). - *
“ I he lighthoufe Mr Winftanley built was beo-un in
the year 1696, and was more than four years inlmild-
mgj not, (fays the archited), for the greatnefs of
the work, but for the difficulty and danger in getting
backwards and forwards to the place. The difficulties
were many, and the dangers not lei's. At length, in the
third year, all the work was raifed, which to the vane
was .eighty feet. Being all finilhed, with the lantern,
and all the rooms that were in it, they ventured to
lodge there foon after midfummer, for the treater difl
patch of the work. But the firft night the weather
came bad, and lo continued, that it was eleven days be¬
fore any boats could come near them again, and not
being acquainted with the height of the fea riling they
were almoft all the time drowned with wet, and5 their
proviflons in as bad a condition, though they worked
night and day to make flicker for themfelves. In this
ftorm they lolt fome of their materials, although they did
v hat they could to lave them 5 but the boat then return-
mg, they all left the houfe to be refrefhed onlhorej and
as loon as the weather permitted, they returned again
and finilhed all, and put up the light on the 14th of
November 1698 j which being fo late in the year, it
was three days before Chriilmas before they had relief
to get on fhore again, and were {almoft at the laft ex¬
tremity for want of provifions j but by good providence,
then two boats came with provifions, and the family that
was to take care of the light.
“1 he fourth year, finding in the winter the effeas the
lea had upon the houfe, and burying the lantern at
times,, although more than 60 feet high j Mr Winftanley
early in the fpring encompafled the building with a new
work of four feet thicknefs from the foundation, making
all folid near 2o feet high 3 and taking down the upper
nnrt nf   J . t • rA .
its proportion, he raifed it forty feet higher than it was
at firft 3 and yet the fea, in time of ftorms, flew up in
appearance 100 feet (b) above the vane 3 and at times
covered half the fide of the houfe and the lantern as if
they were under water.
“ On the finifhing this building, it was generally faid,
that in the time of hard weather, fuch was the height
of
.. II aPPeaf?.that. tht exhibition of thefe water-works continued fome years after the death of Mr Winftanlev
,7lTwfngrm ‘.v 0f rS.eI>tem,bf .I’°9- b“'S “ the Tatler of that date Wm“anle*
(b j Mr bmeaton fays this is ihort of its real height jo feet.
E D Y [
of tlie Teas, that it was very poffible for a fix-aared boat
to be lifted up upon a wave, and driven through the
open gallery of the lighthoufe.
“ In November 17G3, the fabric wanted feme repairs,
and Mr Winftanley went down to Plymouth _ to luper-
intend the performance of them. I he opinion th^
common people was-, that the building would not be oi
long duration Mr Winftanley, however, held different
fentiments. Being amongft his friends previous to his
going off with his workmen on account of thofe repara-
uons, the danger was intimated to him and it was laid,
that one day or other the lighthoufe would certainly be
overfet. To this he replied, “ He was fo well affured
of the ftrength of his building, he fhould only wifhto be
there in the greateft ftorm that ever blew under the face
‘of the heavens^ that he might fee- what effect it would
have upon the ftrufturev” _
“ In this wifh he was foon gratified j for while he was
there with his Workmen and light'keepers, that dread¬
ful ftorm began which raged the molt violently upon
the 26th November 1703, in the night} and of all the
■accounts of the kind which hiftory fumifhes tis with,
we have none that has exceeded this in Great Bri¬
tain, or was more injurious or extenfive in its de»
vaftation.
“ The next morning, when the ftorm Was abated,
nothing of the lighthoufe was to be feen. ’Hie fol¬
lowing account of its dcftnidtion was printed at the
time, by Daniel Defoe in a book entitled The St or 1)1
« The lofs of the lighthoufe called the Edyftone, at
Plymouth, is another article of which we never heard
any particulars, other than this, that at night it was
Handing, and in the morning all the upper part of the
gallery was blown down, and all the people in it perifti-
ed, and, by a particular misfortune, Mr Winftanley the
contriver of it •, a perfon whofe lofs is very much re¬
gretted by fuch as knew him, as a very ufeful man to
his country. The lofs of that lighthoufe is alfo a con-
fiderable damage, as it is very doubtful whether it will
’ever be attempted again j and it was a great fecurity to
the failors, many a good ftiip having been loft there
in former times.
“ It was very remarkable, that as we are informed,
at the fame time the lighthoufe aforefaid was blown
down, the model of it in Mr Winftanley’s. houfe at
Littfebury in Effex, above 200 miles from the lighthoufe,
fell down and was broke to pieces.
“ At Plymouth they felt a full proportion of the
ftorm in its utmoft fury. The Edyftone has been al¬
ready mentioned , but it was a double lofs, in that the
lighthoufe had not been long down when the Wincheifea^
■a homeward-bound Virginia-man, was fplit upon the
rock where that building flood, and moft of her men
drowned.”
“ The great utility of Mr Winftanley’s lighthoufe had
been Sufficiently evident to thofe for whofe ufe it was
creeled • and the lofs of the Winchelfca Virginia-man,
before-mentioned, proved a powerful incentive to fuch
as were interefted, to exert themfelves in order for its
reftoration. It was not, however, begun fo foon as
might have been expefted. In fpring of the year 1^06,
an aft of parliament paffed enabling the Trinity houfe to
rebuild, but it was no earlier than July that it was be¬
gun. The undertaker was a Captain Lovell or Lovett,
\vho took it for the term of ninety nine years, com-
Vot. VII. Part II.
ige 1 E D Y
mencing from the day that a light fltould be exhi- Edyfton ->
bited. ~ .
“ To enable him to fulfil his undertaking, Captain
Lovett engaged Mr John Rudyerd to be his engineer
or architeft 5 and his choice, though Mr Ruiyerd does
not appear to have been bred to any mechanical bull-
nefs or feientifical profeflion, was not ill made. He at
that time kept a linen-draper’s (hop upon Ludgate-hiU.
His want of experience, however, was in a degree adift-
ed by Mr Smith and Mr Notcutt, both Ihip-wnghts
from the king’s yard at Woolwich, who worked with
him the whole time he was building the lighthoufe.
“ It is nOt very material in what way this gentleman
became qualified for the execution of the work : it is
fufticient that he direfted the performance thereof m a
mafterly manner, and fo as perfeftly to anfwer the end
for'which it was intended. He law the errors in the
former building, and avoided them : inftead of a poly¬
gon, he chofe a circle for the outline of his bunding,
and carried up the elevation in that form. His princi¬
pal aim appears to have been ufe and limplicity j and
indeed, in a building fo fituated, the former could
hardly be acquired m its full extent without the latter.
He feems to have adopted ideas the very reverfe of his
predeceffor j for all the unwieldy ornaments at top, the
open galleryq the projefting cranes, and other contri¬
vances, more for ornament and pleafure than ufe, Mr
Rudyerd laid totally afide : he faw, that how beautiful
foever ornaments might be in themfelves, yet when they
are improperly applied, and out of place, they 111 fey a
bad tafte, and betray ignorance of its firft principle,
judgment.
“The building was begun in July 1706, a light
was put up in it the 28th July 1708, and it was
completely finifhed in 1709‘ quantity of ma¬
terials expended in the conftruftion, was $oo tons of
ftone, 12©o tons of timber, 80 tons of iron, and -35
tons of lead 5 of trenails, ferews, and rack-bolts 250b
each.
“ Louis XIV. being at war with England du¬
ring the proceeding with this building, a French pri¬
vateer took the men at work upon it, together with
their tools, and carried them to France 5 and the cap¬
tain was in expeftation of a reward for the atchieve-
ment. While the captives lay in prifon, the tranfaftion
reached the ears of that monarch. He immediately or¬
dered them to be releafed, and the captors to be put
in their place } declaring, that though he was at war
with England, he was not at war with mankind} he
therefore direfted the men to be fent back to their vvonc
with prefents } obferving, that the Edyftone light-houfe
was fo fituated, as to be of equal fervice to all nations
having occafion to navigate the channel that divides
France from England.
In the year 1,715 Captain Lovett being dead, his
property in the Edyftone lighthoufe was fold before a
mailer in chancery to Robert Wefton, Efq. Noyes,
Efq. of Gray’s-Inn } and Cheetham, Efq. an al -
derman of Dublin, who divided the fame into eight
fliares. After a few years feme repairs were found want¬
ing^ and in 1723, Mr Rudyerd being, we fuppofe, then
dead, Mr John Holland, foreman ftiip-wrightinthe dock¬
yard at Plymouth, became overfeer and direftor of the
neceffary reparations ; which office he again executed in
I734' " 4JS Th-
/
E D Y [ 5
“The cataftrophe ofthii lighthoufe took place on the
¥ 2d December 1755, when the light-keeper upon watch,
about two o’clock in the morning, went into the lantern
as ufual to fnuff the candles j he found the whole in a
Imoke *, and upon opening the door of the lantern into
the balcony, a flame inftantly burft from the inlide of
the cupola : he immediately endeavoured to alarm his
companions ; but they being in bed, and afleep, were
not fo ready in coming to his afliftance as the occafion
required. As there were always fome leather buckets
kept in the.houfe, and a tub of water in the lantern,
he attempted to extinguilh the fire by throwing water
from the balcony upon the outfide cover of lead. By
this time his companions arriving, he encouraged them
to fetch up wTater with the buckets from the fea *, but
the height of the place, added to the conflernation which
mult attend fuch an unexpected event, rendered their
eftorts fruitlefs. The flames gathered Itrength every mo¬
ment ; the poor man with every exertion, having the wa¬
ter to throw four yards higher than himfelf, found him-
felf unable to flop the progrefsof the conflagration, and
was obliged to defilt.
“ As he was looking upward with the utmofl: attention
to fee the effedt of the water thrown, a pofition which,
phyfiognomifts tell uS, occafions the mouth naturally to
be a little open, a quantity of lead diflblved by the heat
of the flames fuddenly rufhed like a torrent from the
root, and fell upon his head, face, and flioulders, and
burnt him in a dreadful manner : from this moment he
had a violent internal fenfation, and imagined that a
•quantity ol this lead had palled his throat, and got into
his body. Under this violence of pain and anxiety, as
every attempt had proved ineffectual, and the rage of
the flames was increafing, it is not to be wondered that
the terror and difmay of the three men increafed in pro¬
portion 5 fo that they all found themfelves intimidated,
and glad to make their retreat from the immediate
Icene of horror into one of the rooms below. They
therefore defeended as the fire approached, with no
other profpeCl: than that of fecuring their immediate fafe-
ty, with Icarcely any hopes of being faved from de-
ItruClion.
“ How7 foon the flames wTere feen on the fhore is un¬
certain 5 but early in the morning they were per¬
ceived by fome of the Cawfand filhermen, and intelli¬
gence thereof given to Mr Edwards, of Rame, in that
neighbourhood, a gentleman of fome fortune, and more
humanity, who immediately fent out a filhing-boat
and men to the relief of the diffrefled objeCts in the
lighthoufe (d).
“ The boat and men got thither about ten o’clock,
after the fire had been burning full eight hours; in which
time the three light-keepers were not only driven from
all the rooms and the ftaircafe, but, to avoid the falling
of the timber and red-hot bolts,. &c. upon them, they
were found fitting in the hole or cave on the eaft fide of
the rock under the iron ladder, almoft in a ftate of ftu-
pefaCtion j it being then low water.
“ With much difficulty they were taken off 5 when
finding it impoflible to do any further fervice, they
haliened to Plymouth. No fooner were they fet on
] ED Y
fimre, than one of the men ran away, and was never Euyftone,
aiterwar'ds heard of. This circumltance, though it  
might lead to fufpicions unfavourable to-the man, Mr
Smeaton is of opinion ought not to weigh any thing
againft him, as he fuppofes it to have arifen from
a panic which fometimes felzes weak minds, and
prevents their aCling agreeable to the dictates of right
reafon.
“ It was not long before the dreadful news arrived at
Plymouth. Alderman Tolcher and his Ion immediate¬
ly went to fea, but found it impoffible to do any thing
with efleet. Admiral Weft alfo, who then lay in Ply¬
mouth found, fent a floop properly armed, with a beat
and an engine therein, which alfo carried out Mr Jeflbp
the furveyor. This veffel arrived early in the day.
Many attempts were made to play the engine, but the
agitation of the fea prevented it from being employed
with fuccefs. On the fucceeding days the lire ftiil con¬
tinued, and about the 7th the deftruClion of the whole
was completed.
“ The man who has been mentioned already was
named Henry Hall, of Stonehoufe, near Plymouth, and
though aged 94 years, being of a goodconfiitution, was
remarkably aClive, confidering his time of life. He in¬
variably told the furgeon who attended him, Mr Spry
(now Dr Spry) of Plymouth, that if he would do any
thing effeClual to his recovery, he muft relieve his llo-
mach from the lead which he was fare was within him \
and this he not only told Dr Spry, but all thofe about
him, though in a very hoarfe voice, and the fame afler-
tion he made to Mr Jeffop.—The reality of the afl'er-
tion feemed, however, then incredible to Dr Spry, who
could fcarcely fuppofe it poftible that any human being
could exift after receiving melted lead into the ftomach;
much lefs that he fhould afterwards be able to bear
towing through the fea from the rock, and alio the fa*-
tigue and inconvenience from the length of time he waS
in getting on fhore before any remedies could be applied.
Tire man, however, did not ftiew any fymptoms of be¬
ing much worfe or better until the fixth day after the
accident, when he was thought to mend : he conftant-
ly took his medicines, and fwallowed many things
both liquid and folid, till the tenth or eleventh day 3 af¬
ter which he fuddenly grew worfe 3 and on the twelfth,
being feized with cold fweats and fpafms, he foon after
expired.
His body was opened by Dr Spry, and in the fto¬
mach was found a folid piece of lead of a flat oval form,
which weighed 7 ounces and 5 drachms. So extraordi¬
nary a circumftance appearing to deferve the notice of
the philofophical world, an account of it was fent to the
Royal Society, and printed in the 49th volume of their
tranfa&ions, p. 477.
“ The lighthoufe being thus demolifhed, the proprie¬
tors immediately turned their thoughts to the rebuild¬
ing of it. They had in it a term of near half a cen¬
tury, but fome lhares being fettled by the marriage ar-»
ticks of one of the parties-, fome impediments arofe which
could not be overcome without the aid of parliament,
which was foon obtained. To one of the partners, Ro¬
bert Wefton, Efq. the management of the bulinefs was..
committed.
(d) This benevolent gentleman caught a cold on this occafion which coft him his life.
t-f
&
committed, and iTrcquidte to apply L dm Lmediately began his operations
earl of Macclesfield, then prelident oi the Royal So-
ciety, to recommend a proper perfon to fuperintend ne
work. On communicating the objecl Oa his uiit, a
Macclesfield told him, that there was one of the Royal
Society whom he would venture to recommend to the
bufinefs ; yet that the mod material part oi "hat he
knew of him was, his having within the compafs of the
laid feven vears recommended lumfelf to the Society by
the communication of feveral mechanical inventions and
improvements 5 and though he had at find made it his
bufinefs to execute things in the inldrument way (with¬
out having been bred to the trade) yet on account oi
the merit of his performances, he had been choien a
member of the Society, and that for about three years
paid, having found the bufinefs of a philofophical inurn¬
ment-maker not likely to afford an adequate recom-
pence, he had wholly applied himfelf to fuch branches
of mechanics as were wanted by the proprietors > that^
he was then fomewhere in the north ot England, exe¬
cuting a work : and that as he had always iatisfied his
employers, he would not be likely to undertake what he
could not perform. . , „ ,
“ The perfon thus deferibed was. Mr Smeaton, who
Was written to by Mr Benjamin Wilfon the painter, la¬
conically informing him, that he was the perfon fixed
upon to* rebuild the Edyidone Ughthoufe. But this in¬
timation conveying to his mind no more than a met c no¬
tice that he might, in common with others, deliver
in propofals to repair it, not knowing then that it was
entirely deilroyed, it afforded but httle fatis.aTion,
and he returned only a cool anfwer. Mr Wilfon s re¬
ply was ftill more laconic : That the demolition was to¬
tal, and that as Nathan faid unto David, ‘ ihou art
the man.’ . ^ , .. ... ...
“ Mr Smeaton immediately dwelled himlelt Ox his en¬
gagements in the north, and arrived in London the 23d
of February 1756, and had an interview next day witn
the principal proprietor, dhe mode of. rebuilding
then became the fubjeft of their deliberations,, which
at length ended in a determination to rebuild it .M\n
Hone.
“ On the 5th of April Mr Smeaton firft let his loot on
the Edyftone rock. " He immediately began to take his
meafures for proceeding on the work. He made all the
neceffary inquiries on the Ipot, and irt the neighbour¬
hood. He confidered the nature and quality of the Hone
proper to be tiled, and from Whence it might be ob¬
tained at the bert and cheapeft rates. He vifited the
quarries at Beare in Devonfhire, and the iile^ 01 * I ort-
land, and from the latter of theie places he at length de¬
termined to be {applied with his materials.
u Having proceeded thus far, he returned to London,
and had a meeting with the proprietors, who, for rea-
fons highly honourable to them, confirmed their deter¬
mination to rebuild with ftone. He accordingly pre¬
pared his models and defigns, which were approved
by his employers, and <lire<rted to be exhibited to
the lords of the Admiralty, and the mailers Ox the Iri-
_ nhy houfe. To the former they were Ihewn 5 but
the latter having fixed their time for viewing ttiem
at fo diftant a day'as to hazard the progrefs of the work,
lie determined to fet off for Plymouth without their in-
ipecBom
“He arrived at Plymouth the 'JnJy,175•
D Y
He appointed his Edytior^.
afiirtants, hired his men, fettled their wages, and'—v
drew up rules for their conduct. He alfo hired a piece
of ground for a work-yard. On the 3d of Auguft they
went off to the rock, and continued to work as long a?
the weather would permit.. I he next winter Mr
Smeaton determined to continue at Plymouth, to go
through a courfe of experiments on cements. On the 3d
of June 17 O, the works wrere refumed, and on tm 1 -.to
the firlt ftone was fixed. From this time the ereftion
proceeded with regularity and dilpaudi, and with no
other interruptions than what might be expected from
the nature of the work, until the. 9th of October 1739,
■when, after innumerable difficulties and dangers, a hap¬
py period was put to the undertaking, without the lo s
of life or limb to any one concerned in it, or accident
by which the wrork could be laid to be materially re¬
tarded. .
“ It now remained only to wrait for a ftorm to try
the durability of the building. ihe hard weather
of 1759, 1760, and 1761, appeared to make no im-
preffion. The year 1762 was uffiered in by a tempell
of the firft magnitude, the rage of which was fo great,
that one of thofe who had been ufed to predict it-
downfal was heard to fay, “ If the Edyftone lighthoufe
is now ftandittg, it will Hand to the.day of judgment}
and in reality, from this time its exiftence has been lo
entirely laid out of men’s minds, that whatever ftorms
have happened lince, no inquiry has ever been made
concerning it. So confident was a very intelligent
friend of Mr Smeaton’s of its durability, that he wrote
to him, that he might for ever rid himfelf of any uneafy
thought of the houfe as to its danger from wind and
fea. ,
“ The lighthoufe is attended by three men, wno re¬
ceive 251. a-year each, with an occafional aofence in
fummer. Formerly there were only two, who wratched
alternately four hours and four hours •, but. one iicing
taken ill and dying, the neceffity of an additional hand
became apparent. In this dilemma, the living man
found himfelf in an awkward fituation. Being app.re-
henfive if he tumbled the dead body into the lea, which
was the only way in his poW7er to diipofe of it, he mignt
Be charged wdth murder, he w’as induced for iome time
to let the dead body lie, in hopes that the boat might
be able to land, and relieve him from the diftrefs he
was in. By degrees the body became fo .offenfive,
that it w7as not in his power to get . quit of it without
help } for it was near a month before tne attending
boat could effect a landing ; and then it was not with¬
out the greateft difficulty that it could be done, when
they did land. To fuch a degree was the whole build¬
ing'filled with the flench of the corpfe, that it was all
they could do to get the dead body difpofed of and
thrown into the fea, and it wias fome time au-er tnat Lc- ..
fore the rooms could be freed fri>m the noiiome ftenen
that was left.
“ It is laid, that while two light-keepers only were
employed, on fome difguft they forbore to fpeak. xO
each other. A perfon obfervmg to one of them how
happy thev might live in their ftate of retirement,
“ Yes,” fays the nan, “ very comfortably, if w e could
have the ufe of our tongues 5 but it is now a full month
fince my partner and I have ipoke to eacn other.
“ To ^iefe anecdotes we {hall add one more,
E F F [588
elude. A flioemaker was carrying out to the iight-
houfe in order to be light-keeper. In their way, %s
the fkipper to him, “ How happens it, friend Jacob,
that you fhould chufe to go out to be a light-keeper,
when you can on Ihore (as I am told) earn half-a-crown
and three (hillings a-day in making leathern hofe
(leathern pipes fo called) ; whereas the light-keeper’s
(alary is but 25]. a-year, which is fcarce ten (hillings a-
week.” Says the flioemaker, “ I go to be a light-
keeper, becaufe I don’t like confinement,” After this
anlvver had produced its (hare of merriment, he at lad:
explained himfelf by faying, that he did not like to be
confined to work.
“ J he whole time between the firfl: ftroke upon the
rock and leaving the lighthoufe complete, was three
years nine weeks and three days ; from the 5th of De¬
cember 1755, to exhibiting the light Oftober 1799,
was three years ten months and fixteen days j and
the whole time ot working on the rock 111 days 1 o
hours” (e). J
EEL. See Mur^na, Ichthyology Index.
EsL-FiJhing. See Bobbing and Sniggling.
I he lilver eel may be catched with feveral forts of
baits, as potvdered beef, garden worms, minnows, hens
guts, fdh garbage, &c. The molt proper time for tak¬
ing them is in the night, fattening your line to the
bank Tides, with your laying hook m the water : or a
line may be thrown with good (tore of hooks, baited
and plumbed, with a float to difeover where the line
lies, that they may be taken up in the morning.
Mwrofcopic Eels. See Animalcule, N° 8.
Eels in vinegar, are limilar to thofe in four pafte.
The taite of vinegar was formerly thought to be occa-
lioned by the biting of thefe little animals, but that
opinion has been jultly long exploded. IVIentzelius fays,
he lias obfervefl the actual transformation of thefe little
creatures into flies.
1i.el Spear, a forked inftrument with three or four
jagged teeth, ufed for catching eels : that with the
four teeth is bell, which they (trike into the mud at
the bottom of the river, and if it (trike againit any eels
it never fails to bring them up.
EFFARE', or Effraye', in Heraldry, a term ap¬
plied to a beall rearing on its hind legs, as if it were
frighted or provoked.
EFFECT, in a general fenfe, is that which refults
from, or is produced by, any caufe. See Cause.
EFFEMINATE, womanilh, unmanly, voluptuous.
Effeminate according to the vulgate,
are mentioned in feveral places of Scripture. The word
is there ufed to fignify fuch as were confecrated to fome
profane god, and proftituted themfelves in honour of
him. The Hebrew wmrd hadejh, tranflated efeminatus,
properly fignifies confecrated, and hence was attributed
to thofe of either fex, who publicly proflituted them-
fel \ es in honour of Baal and Aftarte. IVIoles expre(s-
!y forbids thefe irregularities among the Ifraelites j but
the hiftory of the Jews (hows, that they w ere notwith-
ftanding frequently pra&ifed. Levit. xxiii. 18.
EibENDI, m the Turkifli language, fignifies ma-
1
E F F
cence
Jef'■ and accordingly is a title very extenfively ap- EiTervef-
phed; as to the multi and emirs, to the prieils of  
mofques, to men of learning, and of the law. The
grand chancellor of the empire is called reis-effendi.
EFFERVESCENCE, an intelline motion excited
betwixt the parts ot two bodies of dift'erent natures,
when they reciprocally diflblve each other. Effervef-
cences are commonly attended with bubbles, vapours,
fruall jets of the liquid, and a hiding noile 5 and thefe
phenomena are occalioned by the air which at that time
difengages itlelf. Sometimes alfo they are accompanied
with a great degree of heat, from the decompofition of
lome fubitances and the formation of new compounds.
Formerly the word fermentation was alfo applied to
effei vefcences j but now that word is confined, to the
motion naturally excited in animal and vegetable mat¬
ters, and from which new combinations amono- their
principles take* place. b
. EFFIGY, the portrait, figure,, or exad reprefenta-
tion of a perfon.
Efiigy, is alio ufed for the print or impreflion of
a coin, reprefenting the prince’s head who (truck it.
Effigt, to execute or degi'ade in, denotes the execu¬
tion or degradation of a condemned contumacious cri¬
minal, who cannot be apprehended or feized. In
France, they hang a pifture on a gallows or gibbet;
wherein is reprefented the criminal, with the quality or
manner of the punilhmentat the bottom is written
the fentence of condemnation. Such perfons as are
fentenced to death are executed in effigy.
EFFLORESCENCE, among phylicians, the fame
wdth exanthema. See Exanthema..
Efflorescence,, in Chennffryy, denotes the forma¬
tion of a. kind of mealy pow*der on the furface of cer¬
tain bodies. Efflorefcence is occafioned either by de¬
compofition or drying. The efflorefcence which hap¬
pens to cobalt and martial pyrites is of the firfl:; and
that obferved on the cryflals cf foda, Glauber’s fait, &c.
of the latter kind. An efflorefcence is fometimes alfo a
fpecies of cryflallization ; fuch as the beautiful vegeta¬
tions which flioot. up from different faline fubftances-
See Crystallization.
EFFLORESCENTIA, in Botany, (from efflorefco
to bloom) ; the precile time of the year and month inr
which every plant. (hows its firft flowrers.
Some plants flower twice a-year, as is common be¬
tween the tropics ; others oftener, as the monthly role.
The former are called by botaniils- biferce ; the latter,
multiferce.
The time of flowering is determined by the degree cf
heat which each fpecies requires. Mezereon and fnow-
drop produce their flowers in February ; primrofe, in
the beginning of March ; the gi eater number of plants,
during the month of May ; corn,, and other grain, in
the beginning of June ; the vine, in the middle of the
fame month ; feveral compound flowers, in the months
of July and Auguft ; lailly, meadow-faffron flowers in
the month of Oclober, and announces the fpeedy ap¬
proach of winter.
Grafs of Parnaffus always flowers about the time of
cutting
(E) This account is extrafled from a Narrative of the Building, and a Defcription of the Ccriilru61i.cn of the
Edyfi**# Lighthoufe with Stone. By John Stneaton, Civil Engineer, F. R, S-
EJflortf-
eence
II.
Egeria.
E G E C 5^9 ] EGG
1 I. U 1 the different is reckoned by many as a goddefs who prefided over
^I'lSuceTtcory, and bal- the pnegnanc/of wonten ; and W tnaintain that the
fant, feldom dower till after the ollhce : the rS >he fame as larcma. ^ formed ^
■ country men even know, ashy a ‘X-" their males ii which is contained an embryo or feus of
ilice is pad when thefe plants begm to produce their male^ ^ a cort.cal ^ or xhe
^The'temperature of the feafons has a great influ- exterior part of an egg is the Ihell ^ which m a hra, for
ence both in accelerating and retarding the flowering
of plants. All plants are earlier m warm countries ;
hence fuch as are cultivated out of their native foil,
ne ver flower till the heat of the climate, or fituation in¬
to which they are removed, is equal to that under the
influence of which they produced flowers in their own
country. For this reafon, all exotics from warm cli¬
mates are later in this country than many plants which
it naturally produces.
In general, we may obferve, that the plants of the
coldeil countries, and thofe produced on the mountains
in all climates, being of equal temperature, ^ flower
about the fame time, viz. -during our fpnng in Fu-
rOPpiants that grow betwixt the tropics, and thofe of
temperate climates, flower during our fummer..
Plants of temperate climates, fituated under the fame
parallel of latitude with certain parts of Europe, but
removed much farther to the weft, fuch as Canada, Vir¬
ginia, and Mifliffippir do not produce flowers till au-
1 Plants of temperate climates in the- oppofite hernia
fphere to Europe, flower during our winter, which is
the fummer of thefe regions. _ _ ,
Linnaeus and Adanfon have given a fketch of the
different times in which, plants flower at Upfal and
^EFFLUVIUM, in P/iyJto/ogy, a term much _ufed
by philofopbers and phyficians, to. exprefs the minute
particles w-hich exhale from moll, if not all, terreilna
bodies, in form of fenffble vapours.
EFFRONTES, in church hiftory, a feet of here¬
tics, in 1534, who feraped their forehead with a knife
till it bled, and then poured oil into the wound. This
ceremony ferved them inftead of baptifm. I hey are
likewife faid to have denied the divinity of the Holy
SPEFFUSION, the pouring out of any liquid thing
with fome degree of force. In the ancient heathen la—
orifices there were divers effufions of wine and other li¬
quors, called libations.
Effusion, or Fusion, in AJlronotnij,. denotes that
part of the fign Aquarius, reprefented on celeftial
globes and planifpheres, by the water iffuing out of the
urn of the water-bearer.
EFT, or WATER lizard. See Lacerta, Erpe-
TOLOGY Index.
EGERIA, or JEgeria, a nymph held in great
veneration by the Romans. She was courted by Nu-
ma Pompilius ; and, according to.Ovid, Ihe became his
wife. This prince frequently vifited her and that lie
might introduce his laws and new regulations into the
ftate, he folemnly declared before the Roman people,,
that they were previously fanclified and approved by
the nymph Egeria. Ovid fays, that Egeria was fo.dif-
confolate at the death of Numa, that fhe melted into
tears, and was changed into a fountain by Diana. She
inftance, is a white, thin, and friable cortex, including
all the other parts. The fliell becomes more brittle by
being expofed to a dry heat. It is lined everywhere
with a very thin but a pretty tough membrane, whic i
dividing at, or very near, the obtufe end of the egg,
forms a fmall bag, where only air is contained. In new
laid eggs this follicle appears very little, but becomes
larger w-hen the egg is kept.
Within this are contained the albumen or white, and
the vitellus or yolk } each of which have their different
virtues. .
The albumen is a-cold, vifeous,. white liquor in the
egg, different in confiflence in its different parts. It is
obferved, that there are two diftinft albumens, each
of which is enclofed in its proper membrane. Of thefe
one is very thin and liquid : the other is more denfe
and vifeous, and of a fomewhat whiter colour j but,
in old and ftale eggs, after fome days incubation, in¬
clining to a yellow. As this fecond albumen covers
the yolk on all fides, fo it is itfelf furrounded by the
other external liquid. The albumen of a fecundated
egg is as fvveet and free from corruption, during aU
the time of incubation, as it is in new laid eggs 5 as is.
alfo the vitellus. As the eggs of hens confiff of
twro liquors feparated one from another, and diftin-
guiflied by two branches of umbilical veins, one of
which goes to the vitellus, and the other to the albu¬
men j fo it is very probable that they. are . of different
natures, and confequently appointed for different pur-
pofes.. • • 1 •
When the vitellus ■ grows warm with incubation, it
becomes more humid, and like melting wax or fat y
whence it takes up more fpace. For as the foetus increaf-
es, the albumen infenfibly wraftes away and copdenfes .
the vitellus, on the contrary, feems to lofe little or
nothing of its bulk when the foetus is perfecled, and
only appears more liquid and humid when the abdomen
of the foetus begins to be formed.
The chick in "the egg is firft nourifhed by the albu¬
men : and when this is confumed, by the vitellus, as
with milk. If we compare the chalazae to the extre¬
mities of an axis pafling through the vitellus, which is
of a fpherical form, this fphere will be compofed of
two unequal portions, its axis not pafling thiough.its
centre •, confequently, ftnee it is heavier than the white,
its fmaller portion muff always be uppennoft in all pro-
fitions of the egg. . . .
The yellowifh white round fpot, called cicatncula^
is placed on the middle of the fmaller portion of the
yolk 5 and therefore, from what has been faid in the
laft paragranh, mult always appear on the fuperior part
of the vitellus.
Not long before the excluffon of the chick, the
whole yolk is taken into its abdomen j and the fliell,
at the obtufe end of the egg, frequently appears crack¬
ed fome time before the exclufion of the chick. F.he
chick ist fometimes obferved to perforate the fheff with
E G It [ 590
its beak. After exclufion, the yolk is gradually waft¬
ed, being conveyed into the fmall guts by a fmall
]
E G Y
i dudl.
Eggs differ very much according to the birds that
lay them, as to their colour, form, bignefs, age, and
the different way of drefting them: thofe mod ufed
in food are hens eggs 3 of which, fuch as are new laid
are bcft.
As to. the prefervation of eggs, it is obferved that
the egg is always quite full when it is firft laid by the
-iien 3 but from that time it gradually becomes lefs and
lefs fo, to its decay : and however compact and clofe
its ftiell may appear, it is neverthelefs perforated with
a habitude of fmall holes, though too minute for the
difcernment of our eyes, the effeft of which is a daily
decreafe. of matter within the egg, from the time of its
being laid 3 and the perfpiration is much quicker in hot
weather than in cold.
lo preferve the egg frefh, there needs no more
than to preferve it full, and flop its tranfpiration; the
method of doing which is, by flopping up thofe pores
with matter which is not foluble in watery fluids : and
on this principle it is, that all kinds of vamifh, pre¬
pared with fpirit of wine, will preferve eggs frefh for
a long time, if they are carefully rubbed all over the
ftiell : tallow, or mutton fat, is alfo good for this pur-
pofe ; for fuch as are rubbed over with this, will keep
as long as thofe coated over with varnifh.
Artificial Method of Hatching Eggs. See Hatch¬
ing.
EGINA. See TEgina.
EGINHART, fecretary to the emperor Charles
1 he Great, was a German. He is the moft ancient
hiftorian of that nation, and wrote very eloquently for
a .man of the pth century. It is faid, that he infinuated
himfelf fo well into the favour of Imma, daughter to
Charles the Great, that he obtained from her whatever
he defired. Charles the Great, having found out the
intrigue, did not do as Auguftus, who is thought to
nave baniflied Ovid becaufe he believed him to be too
much favoured by Julia 3 for he married the two lovers
together, and gave them a fine eftate in land.
EGLANTINE. See Rosa, Botany Index.
EGLON, a king of the Moabites, who opprefted
the Ifraelites for 18 years (Judges iii. 1 2—14.). Cab¬
inet confounds this fervitude of the Hebrews with that
under Chufan-rifhathaim, making it to fubfift only
eight years., from, the year of the world 2591 to 25993
whereas this fervitude under Eglon lafted 1 8 years, and
commenced in the year of the world 2661, and 62
5 cars after, they had been delivered by Qthniel from
the fubje&ion of Chufan-rilhathaim.
EGRA, a town of Bohemia, formerly imperial, but
now fubjecl to the houfe of Auftxia'. It contains a
great number cf able artificers, and is famous for its
mineral waters. Walienftein, the emperor’s general,
was affaffinated here in 1634. The French became
mailers of this town in 1741 3 but afterwards being
blocked up, they were forced to capitulate on Septem-
ber 7th, 1743* ^ looked upon as a town of the
greateft confequence in Bohemia, except Prague. It
is feated on a river of the fame name, in E. Long. \ 2.
30. N. Lat. 50. 21.
EGRET, in Ornithology, a fpecies of ardea. See
Ardea, Ornithology Index.
4
EGh P f, an extenfive country of Africa, lying be* Eg
tween 30° and 36° of eaft longitude, and between 210 —v
and 310 of north latitude. It is bounded by the Medi¬
terranean on the north 3 by the Red fea and ifthmus of
Suez, which divide it from Arabia, on the eaft 3 by
Abyffinia or Ethiopia, on the fouth 3 and by the de-
ferts of Barca and Nubia, on the weft 3 being 600 miles
in length from north to fouth, and from 100 to 200
in breadth from eaft to wreft.
As a nation, the. Egyptians may with juftice lay DifP
claim to as high antiquity as any in the ivorld. The names
country ivas moft probably peopled by Mizraim the
Ion 01 Ham. and grandfon of Noah.—By its ancient
inhabitants it was called Chejnia, and is Hill called
Chemi in the language of the Copts or native Egyp¬
tians 3 and this name it is xuppoled to have received'
from Ham the fon of Noah. In feripture, we find it
moft generally named Mifraim; though in the Pfalms
it is ftyled the land of Ham.—To us it is beft known
by the. name Egypt, the etymology cf which is more
uncertain.—Some derive it from JEgyptus, a fuppofed
king of the country : others fay it fignifies no more
than “ the land of the CoptsAia in Greek figni-
fying a country, and JEcoptos being eafily foftened into
Agyptus.—The moft probable opinion, however, feems
to be, that it received its name from the blacknefs of
its foil, and the dark colour both of its river and inha¬
bitants : for fuch a blackilh colour is by the Greeks
called ccgyptios from gyps, and eegyps “ a vulture 3” and
by the E&Cms, fubvulturius. For the fame reafon, other
names of a fimilar import have been given to this coun¬
try by the Greeks 5 fuch as Aeria and Melatnbo/us:
the river itfelf was called Me/o or Melas; by the
Hebrews, Shihor ; and by the Europeans, Siris ; all of
\vhich fignify “ black.”
Ancient Egypt is by fome divided into two parts,
the Upper and Lower Egypt: by others into three, the
Upper Egypt, properly fo called, or Thebais; the Middle
Egypt, or Heptanotnes; and the Lower Egypt, the beft
part of which was the Delta, or that fpace encompaf-
fed. by the branches of the Nile. See Thebais, &c.
I he Egyptians, like the Chinefe, pretend to an ex-
ceffive antiquity, pretending to have records for ten,
twenty, or even fifty thoufand years. Thus their hi--
ftory is fo much involved in obfeurity and fable, that
for many ages it muft be palled over in filence.—The
firft mortal king whom the Egyptians own to have*
reigned in that country, was Menes or Menas. At’
what time he reigned, it would be to a very little pur-
p&fe to inquire. He had been preceded, however, by
a fet of immortals, who it feems left him the kingdom
in a very bad lituation : for the whole country, except
Thebais, was a morafs 3 the people alfo were entirely
dellitute of religion, and every kind of knowledge
which could render their life comfortable and happy.
Menes diverted the courfe of the Nile, which before
that time had waftied the foot of a fandy mountain
near the borders of Libya, built the city of Memphis,
inftrufted his fubjefls, and did other tb',"gs of a fimi¬
lar kind which are ufually attributed to the founders
of kingdoms.
O j
From the time of Menes, the Egyptian chronology Invaded
is filled with a lift of 330 kings, who reigned igoo thefliep-
years, but did nothing worthy of notice.—-The firfi!ieicb-
diftincl piece of hiftory we find concerning Egypt, is
the
E G Y [5
Sgvnt. tie irruption of the Shefheris by uhom the country
—-V—' was fubdued ; but whether tins revohmon happened
durine the vaft interval of indolence above mentioned,
or before or after, cannot be known. The affair is
thus related by Manetho. It happened, in the reign
ofTimausking of Egypt, that God being ollplealed
with the Egyptians, they fullered a great revolution :
for a multitude of men, ignoble in their race, took
courage, and, pouring from the call into Egypt, made
war with the inhabitants *, who fubmitted to them with¬
out reiiftance. The {liepherds, however, behaved with
the created cruelty burnt the cities, threw down the
temples of the gods-, and put to death the_ inhabitants*
carrying the women and children into captivity. 1 ms
people came from Arabia, and were called Hycfos, or
kinv-fhepherds. They held Egypt in fubjeftion for 259
years ; at the end of which period, they were obliged
by a king-of Upper Egypt, named Amojis, ox Lueth-
tno/tSf to leave the country. I his prince s father had,
itfeems, gained great advantages over them, and Ihut
them up in a place called Aborts, or Avans, contain¬
ing 10,000 acres of land. Here they were clofely be-
fieged by Amofis, with an army of 400,000 men but
atlailthe king, finding himfelfunable to reduce tnem
by force, propofed an agreement, which was. readily
accepted. In cohfequence of this agreement,^ the mep-
herds withdrew from Egypt with their families, to t e
number of 240,000 and, taking the way oi the de-
fert, entered Syria: but fearing the Affynans, who were
then very powerful, and mailers of Alia, they enter¬
ed the land of Judaja and built there a city capable
of holding fo great a multitude, and called it Jt 1 u-
faletn. , . , ,
' According to Mr Bruce, the fhepherds wno invaded
Egypt were no other than the inhabitants of Barabra.
They were, he fays, carriers to the Cuihites vho li\ed
farther to the fouth. The latter had built the many
ftately temples in Thebes and other cities of Egypt
though, according to him, they had no dwelling places
but holes or caves in the rocks. Being a commercial
people, they remained at home colie tiling and prepa¬
ring their articles, which were difperfed by the bara-
bers or {hepherds already mentioned.^ Ihele, from the
nature of their employment, lived in moveable habi¬
tations, as the Tartars do at this day. By the He-
brews, he tells us, they were called/)/^/1, but/bep/icrds
by every other people-, and from the name barabcr,^ the
word Barabra is derived. By their employment, which
was the difperfing the Arabian and African goods all
over the continent, they had become a great an
powerful people; and from their oppofite difpofitions
and manners, became very frequently enemies to the
Egyptians. To one Salatis our author afcribes the
deilruriion of Thebes in Upper Egypt, fo much cele¬
brated by Homer for its magnificence. But this cer¬
tainly cannot be the cafe 4 for Homer wrote long af¬
ter the time of Jofeph : and we find that even, then
the Egyptians had the Ihepherds in abhorrence, in all
probability becaufe they had been grevioufly oppreffed
by them, Mr Bruce counts three invafions of thefe
people; the firft that of Salatis already mentioned, who
overthrew the firll dynafty of Egyptian kings nom Mc-
nes, and dellroyed Thebes : the fecoud was that of
Sabacco or So; for according to him this was not
ike name of a iingle prince, but of a people, and figm-
91 ] EG Y ^
fies fliepherds: and the third, after the building of Mem
phi's, where 240,000 of them were beiieged as. aooye
mentioned. But accounts of this kind are evidently
inconliftent in the higheft degree ; for how is it poi -
fible that the third invafion, antecedent to^the building
of Jerufalem, could be pcfterior to the fee on d, it the
latter happened only in the days of Hezeniah ?
In thefe early ages, however, it would feem tuai. t ic
kingdom of Egypt had beett very powerful and its do¬
minion very widely extended; fmee we find it faicl, t.iat
the Baclrians revolted from Ofymandyas, another E-
gyptian king of very high antiquity, and oi whom
wealth the moil marvellous accounts.are given. .
After au unknown interval of time trom this mo¬
narch, reigned Setoftris. He was the firft great war-
rior whofe conquefts are recorded with any degree ot
diftinanefs. In what age of the world he lived, is
uncertain. Some chronologers, among whom is Sir
Ifaac Newton, are of opinion, that he is the Seiac
or Shiihak, who took Jemlalem in the reign ot Rc-
hoboam the fon of Solpmon. Others, however, place
him much earlier ; and Mr Whifton will. have him
to be the Pharaoh who refufed to part with the lf-
raelites, and was at laft drowned in the Red fea. Mr
Bryant endeavours to prove that no tuch ^ per Ion e\ er
exifted; but that in his hiftory as well ras that of many
ancient heroes, we have an abridgment of that of the
Cuihites or Babylonians, who fpread themfelves over
great part of the then known world, and everywh.eie
brought the people in iubjeelion to tnem.^ His reign,
is reckoned the moft extraordinary part of the Egyp¬
tian hi dory ; and the following ieems to. be tne leak
fabulous account that can be got ot it. 1 he father ot
Stfoftris was told in a dream, by the god Vulcan, that
his ion, who was then newly born, or perhaps Itilt
unborn, ihould be lord of the whole earth. His la¬
ther, upon the credit of this viuon, got together a.l
the males in the land of Egypt that were born on thfc
fame day with Sefoftris ; appointed nurfes^ and pro¬
per perlons to take care of them, and had tnem treat¬
ed like his own child ; being perfuaded that they who
had been the conftant companions of his youth would
prove the moft faithful minifters and. ioldiers. . As
thev grew up, they were inured to laborious exercifes ;
and, in particular, were never permitted to taile any
food till they had performed a courfe of 180 furlongsy,
upwards of 22 of our miles. When the . old king ima¬
gined they were fufnciently educated in the martial
way he defigned them to follow, tney were feht by way
of trial of their abilities againft the Arabians. In this
expedition Sefoftris proved fuccefsful, and in the end
fubdued that people who had never before been con¬
quered. He was lent to the weft ward, and conquered
the greateft part of Africa ; nor could he be. flopped,
in his career till he arrived at the Atlantic ocean.
Whilft he was on this expedition, his father died ;
and then Sefoftris refolved to fulfil the prediction of.
Vulcan, by actually conquering the whole world. As
he knew that this mult take up a long time, he pre¬
pared for his journey in the belt manner poflible. I he-
kingdom he divided into 36 provinces, and endeavoui-
ed to fecure the affedtions of the people by g^tti both
of money and land. He forgave all wno had been
guilty of offences, and difeharged the debts ol ail
his ioldiers. He then conftituted his brother Armais.
ft G Y [ 59
>t. tile fupreme regent; but forbade him to ufe the diadem,
!md commanded him to offer no injury to the queen
or her children, and to abftain from the royal concu¬
bines. His army confifted of 600,060 foot, 24,000
horfe, and 27,000 chariots. Befides thefe land forces,
he had at fea two mighty fleets; one, according to Dio¬
dorus, of 400 fail. Of thefe fleets, one was defigned
to make conquefts in the weft, and the other in the
eaft; and therefore the one was built on the Mediter¬
ranean and the other on the Red fea. The firft of
thefe conquered Cyprus, the coaft of Phoenicia, and
feveral of the iflands called Cyclades ; the other con¬
quered all the coalts of the Red fea ; but its progrefs
was flopped by fhoals and difficult places which the na¬
vigators could not pafs, fo that he feems not to have
made many conquefts by fea.
With the land forees Sefoflris marched againft the
Ethiopians and Troglodites ; whom he overcame, and
obliged them to pay him a tribute of gold, ebony, and
ivory. From thence he proceeded as far as the pro¬
montory of Dira, which lay near the ftraits of Babel-
mandel, where he fet up a pillar with an infeription in
facred characters. He then rtiardhed on to the coun¬
try where cinnamon grows, or at leaft to fome country
where cinnamon at that time was brought, probably
fome place in India ; and here he in like manner fet
up pillars, which were to bt feen for many ages after.
As to his farther conquefts, it is agreed by almoft all
authors of antiquity, that he overran and pillaged the
whole continent of Afia, and fome part of Europe.
•He crofted the Ganges, and erefted pillars on its
banks ; and from thence he is faid to have marched
eaftward to the very extremity of the Afiatic conti¬
nent. Returning from thence, he invaded the Scy-
1 thians and Thracians ; but all authors do not agree
that he conquered them. Some even affirm, that he
was overthrown by them with great flaughter, and ob¬
liged to abandon a great part of his booty and mili¬
tary Itores. But whether he had good or bad fuc-
cefs in thefe parts, it is a common opinion that he
fettled a colony in Colchis. Herodotus, however, who
gives the moft particular account of the conquelts of
this monarch, does not fay whether the colony was
defignedly planted by Sefoftris : or wBether part of
his army loitered behind the reft, a#id took up their
refidence in that region. From his own knowledge,
he aflerts, that the inhabitants of that country were
undoubtedly of Egyptian defeent. This was evident
from the perfonal refemblance they bore to the Egyp¬
tians, who wrere fwarthy complexioned and frizzle
haired ; but more efpecially from the conformity ©f
their cultoms, particularly Oircufncifion.
The utmoft boundary of this mighty monarch’s con--
quefts, however, wras in the country of Thrace ; for
beyond this country his pillars wrere nowhere to be
feen. Thefe pillars he was accuftomed to fet up in
every country which he conquered, with the following
infeription, or one to the fame purpofe : “ Sefoftris,
kings of kings, and lor*! of lords, fubdued this country
by the pow er of his arms.” Befides thefe, he left alfo
ftatues of himfelf; twro of which, according to Hero¬
dotus, were to be feen in his time; the one on the
Toad between Ephefus and Phocsea, and the other be¬
tween Smyrna and Sardis: they were armed after the
Ethiopian and Egyptian manner; holding a javelin in
3
ns to
2 ] £ C5 Y
one hand and a bow in the other. Acrofs the hfeaft Egypt
they had a line drawn from one fhoulder to the other, »•
wdth the following infeription : “ This region I ob¬
tained by thefe my fhoulders.” They w’ere fniftaken
for images of Memnon.
The reafons given by Sefoftris for his returning intoRet,^
Egypt from Thrace, and thus leaving the conqueft of Egypt,
the world unfinifhed, were the w-ant of provilions for
his army, and the difficulty of the paffes. Moft pro¬
bably, however, his return w-as haftened by the intelli¬
gence he received from the high prieft of Egypt, con-
■cerning the rebellious proceedings of his brother; wdiof
encouraged by his long abfence, had affumed the dia¬
dem, violated the queen, and alfo the royal concu¬
bines. On receiving this news, Sefoftris haftened from
Thrace; and at the end of nine years came to Pelu-
fium in Egypt, attended by an innumerable multitude
of captives taken from many different nations, and
loaded with the fpoils of Afia. T he treacherous bro¬
ther met him at this city 3 and it is faid, with very
little probability, that Seloftris accepted of an invita¬
tion to an entertainment from him. At this he drank
freely, together with the queen and the reft of the
royal family. During the continuance of the enter¬
tainment, Armais caufed a great quantity of dried
reeds to be laid round the apartment where they were
to fleep; and as foon as they were retired to reft fet
fire to the reeds. Sefoltris perceiving the danger he
was in, and that his guards, overcharged with liquor,
were incapable of affifting him, ruffled through the
flames, and was followed by his wrife and children. In
thankfgiving for this wonderful deliverance, he made
feveral donations to the gods, particularly to Vulcan
the god of fire* He theft took vengeance on his bro¬
ther Armais, faid to be the Danaus of the Greeks,
who, being on this oCcafion driven out of Egypt, with¬
drew into Greece.
Sefoftris now laid afide all thoughts of war, and ap- His great
plied himfelf wholly to fuch w-orks as might tend to works,
the public good, and his own future reputation. In or¬
der to prevent the incurfions of the Syrians and Ara¬
bians, he fortified the eaft fide of Egypt with a tyall
which ran from Pelufium through the defert to Helio¬
polis, for iSyi- miles. He railed alfo an incredible
number of vaft and lofty mounts of earth, to w hich he
removed fuch towns as hadfbefore been fituated too
lowq in order to fecure them from the inundations of
the Nile. All the way from Memphis to the fea he
dug canals wdfich branched out from the Nile; and not
only made an eafier communication between different
places, but rendered the country in a great meafure ini-
paffable to an enemy.- ?He erected a temple in every
city in Egypt, and dedicated it to the fupreme deity
of the place ; but in the courfe of fuch a great under¬
taking as this neceffarily muft have been, he took care
not to employ any of his Egyptian fubjeits. Thus he
fecured their affection, and employed the vaft multi¬
tude of captives he had brought along with him ; and
to perpetuate the memory of a tranfadtion fo remark¬
able, he caufed to be inferibed on all thefe temples,
“ No one native laboured hereon.” In the city of
Memphis, before the temple of Vulcan, he raifed fix
gigantic ftatues, each of one (tone. Two of them were
30 cubits high, reprefenting himfelf and his wife ; the
other four were 29 cubits each, and reprefented his
four
E G Y
[ 593 ]
E G Y
Cgvpt.
His uenth.
6
Origin of
the fable of
Proteus.
Arrival of
Paris and
Helen in
■Egypt.
Four Tons. Thefe he dedicated to Vulcan in memory
of his above-mentioned deliverance. He railed alio
two obehlks of marble 120 cubits high, and charged
them with infcriptions, denoting the greatnefs of his
power, his revenues, &c.
The captives taken by Sefoftris are faid to have been
treated with the greateil barbarity ; fo that at lull they
refolved at all events to deliver themfelves from a ler-
vitude fo intolerable. The Babylonians particularly
were concerned in this revolt, and laid wafte the coun¬
try to fome extent j but being offered a pardon and a
place to dwell in, they were pacified, and huilt for them¬
felves a city, which they called Babylon, .towards the
conquered princes wrho waited on him with their tri¬
bute the Egyptian monarch behaved with unparalleled
infolence. On certain occafions he is faid to have un-
harnaffed his horfes, and, yoking kings together, made
them draw his chariot. One day, however, obfeiving
one of the kings who drew his chariot to look back
upon the wheels with great earneitnefs, he afked whaj
made him look fo attentively at them ? The unhappy
prince replied, “ O king, the going round of the wheel
•puts me in mind of the viciflitudes of fortune : for as
every part of the wheel is uppermolt and lowermoil by
turns, fo it is with men } who one day fit on a throne,
and on the next are reduced to the vileft degree of
flavery.” This anfwer brought the infulting conqueror
to his fenfes 5 lo that he gave over the practice, and
thenceforth treated his captives with great humanity.
At length this mighty monarch loft his fight, and laid
violent hands on himfelf.
After the death of Sefoftris, we meet with another
chafm of an indeterminate length in the Egyptian
hiftory. It concludes with the reign of Amafis or Am-
tnofis •, who being a tyrant, his ftibjefts joined Adi-
fanes the king of Ethiopia to drive him out.— I hus
Adfifanes became mafter of the kingdom j and after
his death follows another chafm in the hiftory, during
which the empire is faid to have been in a ftate of
anarchy for five generations.— ihis period brings us
dowrn to the times of the .Trojan wrar. Ihe reigning
prince in Egypt was at that time called Cetes ; by the
Greeks, Proteus. 1 he priefts reported that he wyas a
magician j and that he could affume any fliape he
pleafed, even that of fire. I his fable, as told by the
Greeks, drew its origin from a cuftom among the E-
gyptians, perhaps introduced by Proteus. They were
ufed to adorn and diftinguifli the heads of their kings
with the reprefentations of animals or vegetables, or
even with burning incenfe, in order to ftrike the be¬
holders with the greater awe. Whilft Proteus reigned,
Paris or Alexander, the fon of Priam king of Troy,
was driven by a ftorm on the coaft of Egypt, with
Helen, wdrom he was carrying off from her hufband.
But when the Egyptian monarch heard of the breach
of hofpitality committed by Paris, he feized him, his
miftrefs, and companions, with all the riches he had
brought away with him from Greece. He detained
Helen, with all the effeas belonging to Menelaus her
hufhand, promifmg to reftore them to the injured party
whenever they wTere demanded ; but commanded Paris
and his companions to depart out of his dominions in
three days, on pain of being treated as enemies. In
what manner Paris afterwards prevailed upon Proteus
to reftore his miftrefs, we are not told , neither do we
Vol. VII. Part II,
know any thing further of the tranfadlions of this Egypt. ^
prince’s reign nor of his fucceffors, except what has ~ ^
entirely the air of fable, tiu the days of Sabbaco the iigypt COn«
Ethiopian, wrho again conquered this kingdom. Heqnered by
began his reign with an act of great cruelty, caufmgSabbaco.
the conquered prince to be burnt alive: neverthelefs, he
no fooner faw himfelf firmly eftablifhed on die throne
of Egypt, than he became a new man •, fo that he is
highly extolled for his mercy, clemency, and wifdom.
He is thought to have bee.-- the So mentioned in Scrip¬
ture, and who entered into a league with Hofhea king
of Ifrael againft Shalmanefer king of Affyria. He is
faid to have been excited to the invafton of Egypt by
a dream or vifion, in which he was allured that he
fhould hold that kingdom for 50 years. Accordingly,
he conquered Egypt, as had been foretold j and at the
expiration of the time above mentioned, he had another
dream, in which the tutelar god of Thebes acquainted
him, that he could no longer hold the kingdom of
Egypt with fafety and happinefs, unlefs he maffacred
the priefts as he paffed through them with his guards.
Being haunted with this vifion, and at the fame time
abhorring to hold the kingdom on iuch terms, he fent
for the priefts, and acquainted them with what feemed
to be the will of the gods. Upon this it was concluded,
that it wras the pleafure of the Deity that Sabbaco
fhould remain no longer in Egypt j and therefore he
immediately quitted that kingdom, and returned to
Ethiopia.
Of Anyjias, who was Sabbaco’s immediate fuccefibr,
rve have no particulars worth notice. After him reign- p
ed one Sethon, who w^as both king and prieft of Vul-Remark-
can. He gave himfelf up to religious contemplation j able itory
and not only neglefled the military clafs, but deprived01 baion‘
them of their lands. At this they were fo much incen-
fed, that they entered into an agreement not to bear
arms under him j and in this ftate of affairs Sennache¬
rib king of Aflyria arrived before Pelufium with a
mighty army. Sethon now applied to his foldiers, but
in vain: they unanimoufly perfifted in refufing to march
under his banner. Being therefore deftitute of all hu¬
man aid, he applied to the god Vulcan, and requefted
him to deliver him from his enemies. WTiilft he was
yet in the temple of that god, it is faid he fell into a
"deep deep ; during which he faw Vulcan Handing at
his fide, and exhorting him to take courage. He pro-
mifed, that if Sethon would but go out againft the
Affyrians, he fhould obtain a complete viffory over
them. Encouraged by this affurance, the king affem-
bled a body of artificers, fhop-keepers, and labourers j
and, with this undifeiplined rabble, marched towards
Pelufium. He had no occafion, however, to fight j for
the very night after his arrival at Pelufium, an innu¬
merable multitude of field rats entering the enemies
camp, gnawed to pieces the quivers, bowftrings, and
fhield ftraps. Next morning, when Sethon found the
enemy difarmed, and on that account beginning to fly,
he purfued them to a great diftance, making a terrible
daughter. In memory of this extraordinary event, a
ftatue of Sethon was erefted in the temple of Vulcan,
holding in one hand a rat, and delivering thefe wrords j
“ Whofoever beholdeth me let him be pious.”
Soon after the death of Sethon, the form of govern¬
ment in Egypt was totally changed. The kingdom
was divided into twelve parts, over which as many of
4 F the
Egypt.
Reign cf
Pf.immiti-
chus.
ii
Succeeded
by Nechu?.
E G Y [
the chief nobility prefided. This divifion, however,
fubliiled but for a fliort time. Pfammitichus, one of
the twelve, dethroned all the reft, 15 years after the
divilion had been made. The hiftory now begins to
be divefted of fable 5 and from this time may be ac¬
counted equally certain with that of any other nation.
J. ne vaft conquefts of Sefoftris were now no longer
known j for Pfammitichus poffefied no more than the
country of Egypt itfelf. It appears, indeed, that none
of the fuccelfors of Sefoftris, or even that monarch him-
felf, had made ufe of any means to keep in fubjedlion
the countries he had once conquered. Perhaps, indeed,
his defign originally was rather to pillage than to con¬
quer *, and therefore, on his return, his vaft empire va-
(nifhed at once. Pfammitichus, however, endeavoured
to extend his dominions by making war on his neigh¬
bours j but by putting more confidence in foreign auxi¬
liaries than in his own fubje&s, the latter were fo
much offended, that upwards of 200,000 fighting men
emigrated in a body, and took up their refidence in
Ethiopia. To repair this lofs, Pfammitichus earneftly
applied Kimfelf to the advancement of commerce •, and
opened his port to all ftrangers, whom he greatly ca-
reffed, contrary to the cruel maxims of his predecef-
foas, wrho refuted to admit them into the country. He
alfo laid fiege to the city of Azotus in Syria, which
held out for 29 years againft the whole ftrength of the
kingdom ; from which we may gather, that, as a war¬
rior, Pfammitichus vras by no means remarkable. He
is reported to have been the firft king of Egypt that
drank wine. He alfo lent to difcover the fprings of
the Nile j and is faid to have attempted to difcover the
moft ancient nation in the wmrld by the following me¬
thod. Having procured two newly born children, he
caufed them to be brought up in fuch a manner that
they never heard a human voice. He imagined that
thefe children wrould naturally fpeak the original lan¬
guage of mankiad : therefore, w-hen, at two years of
age, they pronounced the Phrygian wrord becos (or
fome found refembling it), wliich fignifies bread, he
concluded that the Phrygians w'ere the moft ancient
people in the world.
Nechus, the fqn and fucceffor of Pfammitichus, is
the Pharaoh-Necho of Scripture, and was a prince of an
enterpriling and warlike genius. In the beginning of
his reign, he attempted to cut through the ifthmus of
Suez, between the Red fea and the Mediterranean j
but, through the invincible obftacles which nature has
thrown in the way of fuch undertakings, he w7as obli¬
ged to abandon the enterprife, after having loft 1 20,000
men in the attempt. After this he fent a fliip, manned
with fome expert Phoenician mariners, on a voyage to
explore the coafts of Africa. Accordingly, they per¬
formed the voyage ; failed round the continent of A-
frica 5 and after three years returned to Egypt, where
their relation was deemed incredible.
The moft remarkable wars in which this king wras
Ej-ypt.
11
His wars _ ^
with Jofiah engaged are recorded in the facred writings. He^went
and Nebu¬
chadnez¬
zar.
out againft the king of Affyria, by the divine com¬
mand, as he himfelf told Jofiah j but being oppofed by
the king of Judea, he defeated apd killed him at Me-
giddo $ after which he fet up, in that country, King
Jehoiakim, and impofed on him an annual tribute of 100
talents of filver and one talent of gold. He then pro¬
ceeded againft the king of Affyria j and weakened him
594 ] E G Y
fo much, that the empire was foon after diffolved.
Thus he became mafter of Syria and Phoenicia j but
in a Ihort time, Nebuchadnezzar king of Babylon came
againft him with a mighty army. The Egyptian ma-
narch, not daunted by the formidable appearance of
his antagonift, boldly ventured a battle j but was over¬
thrown with prodigious flaughter, and Nebuchadnez¬
zar became mafter of all the country to the very gates
of Pelufium.
The reign of Apries, the Pharaoh-Hophra of Scrip-Apries a
ture, prefents us with a new revolution in the Egyp-rnart(al and
tian affairs. He is reprefented as a martial prince, ^ufceislu*
and in the beginning of his reign very fuccefsful, Her>U“Ce‘
took by ftorm the rich city of Sidon •, and having over¬
come the Cypriots and Phoenicians in a fea fight, re¬
turned to Egypt laden with fpoil. This fuccefs pro¬
bably incited Zedekiah king of Judaea to enter into an
alliance with him againft Nebuchadnezzar king of
Babylon. The bad fuccefs of this alliance was fore¬
told by the prqphet Jeremiah j and accordingly it hap¬
pened. For Nebuchadnezzar having fat down with
his army before Jerufalem, Apries marched from E-
gypt with a defign to relieve the city ; but no fooner
did he perceive the Babylonians approaching him, than
he retreated as faft as he could, leaving the Jews ex-
pofed to the rage of their mercilefs enemies 5 who were
thereupon treated as Jeremiah had foretold j and by
this ftep Apries brought upon himfelf the vengeance I4
denounced by the fame prophet. The manner in which Bad confe-
thefe prediftions were fulfilled is as follows : The Cy- 'lances of
reneans, a colony of the Greeks, being greatly ftrength- e-
ened by a numerous fupply of their countrymen under
their third king Battus ftyled the Happy, and encou¬
raged by the Pythian oracle, began to drive out their
Libyan neighbours, and (hared their poffeftions among
themfelves. Hereupon Andica king of Libya fent
a fubmiftive embafly to Apries, and implored his pro-
teclion againft the Cyreneans. Apries complied with
his requeft, and fent a powerful army to his relief.
The Egyptians were defeated with great flaughter j and
thofe who returned complained that the army had been
fent off by Apries in order to be deftroyed, and that
he might tyrannize without controul over the remain-
der of his fubjetts. This thought catching the atten-His fubjedb
tion of the giddy multitude, an almoft univerfal defec-reV0lt-
tion enfued. Apries fent one Amafis, a particular
friend, in whom he thought he could confide, to bring
back his people to a lenfe of their duty. But by this
friend he was betrayed ; for Amafis, taking the op¬
portunity of the prefent ferment, caufed himfelf to be
proclaimed king. Apries then defpatched one Patar-
bemis, with orders to take Amafis, and bring him alive
before him. This he found impoffible, and therefore
returned without his prifoner j at wThich the king wras
fo enraged, that he commanded Patarbemis’s nofe and
ears to be cut off. This piece of cruelty completed
his ruin j for when the reft of the Egyptians wrho con¬
tinued faithful to Apries beheld the ^inhuman mutila¬
tion of fo w'orthy and noble a perfcn as Patarbemis
was, they to a man deferted Apries, and wTent over to
Amafis.
Both parties now prepared for war; the ufurper hav¬
ing under his command the wEole body of native E-
gyptians; and Apries only thofe lonians, Carians, and
other mercenaries wiiom he could engage in his fer-
vice.
E G Y
[ 595 ]
E G Y
Egypt.
16
A pries de¬
feated and
taken pri-
for er by
Amafis.
T7
Egypt in¬
vaded by
Nebuchad-
iS
Happy ad-
miniftra-
tion of
Amafis.
x9
Offends
Cambyfes
king of
Peiiia.
vice. The army of Apries amounted only to 30,000 }
but, though greatly inferior in number to the troops
of his rival, as he well knew that the Greeks were much
fuperior in valour, he did not doubt of victory. ^ Nay,
fo far was Apries puffed up with this notion, that he
did not believe it was in the power even of any god
to deprive him of his kingdom. The two armies foon
met, and drew up in order of battle near Memphis. A
bloody engagement enfued •, in which, though the army
of Apries behaved with the greateil reiolution, they
were at laft overpowered with numbers, and utterly de¬
feated, the king himfelf being taken prifoner. Amafis
now took poffemon of the throne without oppofition.
He confined Apries in one of his palaces, but treated
him with great care and refpeft. The people, how¬
ever, were implacable, and could not be fatished while
he enioyed his life. Amafis, therefore, at laft found
himfelf obliged to deliver him into their hands. Thus
the prednElion received its final completion . Apries
was delivered up to thofe wfio fouglit his life ; and who
no fooner had him in their power, than they ftrangled
him, and laid his body in the fepulchre of his ancef-
tors.
During thefe inteftine broils, which muft have great¬
ly weakened the kingdorn, it is probable that Nebu-
' chadnezzar invaded Egypt. He had been for 1 3 y ears
before this employed in befieging Tyre, and at laft had
nothing but an empty city for his pains. To make
himfelf fome amends, therefore, he entered Egypt, mi-
ferably haraffed the country, killed and carried away
great numbers of the inhabitants, fo that the country
did not recover from the effeffs of this incurlion for a
long time after. In this expedition, however, he feems
not to have aimed at any permanent corvqueft, but to
have been induced to it merely by the love of plunder,
and of this he carried wdth him an immenfe quantity to
Babylon.
During the reign of Amafis, Egypt is faid to have
been perfedlly happy, and to have contained 20,000
populous cities. That good order might be kept
among fuch vaft numbers of people, Amafis enacted a
law, by which every Egyptian was bound once a-year
to inform the governor of his province by what means
he gained his livelihood ; and if he failed of this, to
put him to death. The fame puniftiment he decreed to
thofe who could not give a fatisfactory account of
themfelves.
This monarch was a great favourer of the Greeks,
and married a woman of Grecian extract. To many
Greek cities, as well as particular perfons, he made
confiderable prefents. Befides thefe, he gave leave to
the Greeks in general to come into Egypt, and fettle
either in the city of Naucratis, or carry on their trade
upon the fea coafts *, granting them alfo temples, and
places where they might ereA temples to their own
deities. He received alfo a vifit from Solon the cele¬
brated Athenian lawgiver, and reduced the illand of
Cyprus under his fubje&ion.
This great profperity, however, ended with the death
of Amafis, or indeed before it. The Egyptian mo¬
narch had fome how or other incenfed Cambyles king
of Perfia. The caufe of the quarrel is uncertain ; but
whatever it was, the Perfian monarch vowed the de-
ftruAion of Amafis. In the mean time Plumes of Ha-
licarnaflus, commander of the Grecian auxiliaries in the
20
pay of Amafis, took fome private difguft j and leaving Egypt.
Egypt, embarked for Perfia. He was a wife and able v
general, perfectly well acquainted with every thing that
related to Egypt j and had great credit with the Greeks
in that country. Amafis was immediately fenfible how
great the lofs of this man would be to him, and there¬
fore lent after him a trufty eunuch with a fwift galley.
Phanes was accordingly overtaken in Lycia, but not
brought back 5 for making his guard drunk, he con¬
tinued his journey to Perfia, and prefented himfelf oe-^
fore Cambyfes, as he was meditating the deftruftion Oi
the Egyptian monarchy.
At this dangerous crifis alfo, the Egyptian monarch And Poly-
imprudently made Polycrates the tyrant of Samos hiscmtc^ty-
enemy. This man had been the molt remarkable per-
haps of any recorded in hiftory, for an uninterrupted
courfe of fuccefs, without the intervention of one fingle
unfortunate event. Amafis, wbo was at this time in
ftrift alliance with Polycrates, wrote him a letter, in
which, after congratulating him on his profperity, he
told him that he was afraid left his fucceffes were too.
many, and he might be fuddenly thrown down into
the greateft mifery. For this reafon he adviled him
voluntarily to take awT.ay fomething from his own hap-
pinefs j and to caft away that which would grieve him
moft if he was accidentally to lofe it. Polycrates fol¬
lowed his advice, and threw into the fea a fignet of
ineftimable value. This, however, did not anfwer the
intended purpofe. The fignet happened to be fvval-
lowed by a fiih, which was taken a few days atter-
wards, and thus was reftored to Polycrates. Of this
Amafis wTas no fooner informed, than, conlidering Po¬
lycrates as really unhappy, and already on the brink of
deftruclion, he refolved to put an end to the friendlliip
which fubfifted between them. For this purpofe he
defpatched a herald to Samos, commanding him to
acquaint Polycrates, that he renounced his alliance,
and all the obligations between them } that he might
not mourn his misfortunes wdth the forrow of a friend.
Thus Amafis left Polycrates at liberty to aft againft
him, if he chofe to do fo 5 and accordingly he offered
to aflift Cambyfes with a fleet of drips in his Egyptian
expedition.
Amafis had not, however, the misfortune to fee the
calamities of his country. He died about 525 years
before Chrift, after a reign of 44 years j and left the 21
kingdom to his fon Pfammenitus, juft as Cambyfes was Egypt in-
approaching the frontiers of the kingdom. The new Carsbyfe*.
prince was fcarce feated on the throne, wdren the Per-
fians appeared. Pfammenitus drew together what forces
he could, in order to prevent them from entering the
kingdom. Cambyfes, however, immediately laid fiege
to Pelufium, and made himfelf mafter of it by the fol-
lowing ftratagem : he placed in the front of his army
a great number of cats, dogs, and other animals that
wrere deemed facred by the Egyptians. He then at¬
tacked the city, and took it without oppofition % the
garrifon, which confifted entirely of Egyptians, not
daring to throw a dart or fhoot an arrow againft
their enemies, left they (hould kill fome or the holy
animals.
Cambyfes had fcarce taken poffeflion of the city, an^
when Pfammenitus advanced againft him wdth a nume- defeat of
rous army. But before the engagement, the Greeks the Egyp-
who ferved under Pfammenitus, to (how their indig-tiaos.
4 F 2 nation
E G Y [ 596 ] E G Y
Egypt.
Tieir
dreadful
punifliment
by Camby-
fes.
nation againil their treacherous countryman Phanes,
brought his children into the camp, killed them in the
prefence of their father and of the two armies, and
then drank their blood. The Perfians enraged at fo
cruel a light, fell upon the Egyptians with the utmoft
fury, put them to flight, and cut the greatefl: part of
them in pieces. Thofe who efcaped fled to Memphis,
■where they were foon after guilty of a horrid outrage,
Cambyfes fent a herald to them in a fliip from Mity-
lene : but no fooner did they lee her come into the
port, than they flocked down to the Ihore, deftroyed
the Ihip, and tore to pieces the herald and all the crew,
afterwards carrying their mangled limbs into the city,
in a kind of barbarous triumph. Not long after, they
were obliged to furrender : and thus Pfammenitus fell
into the hands of his inveterate enemy, who was now
enraged beyond meafure at the cruelties exercifed upon
the children of Phanes, the herald, and the Mitylenean
failors.
The rapid fuccefs of the Perlians ftruck with fuch
terror the Libyans, Cyreneans, Barcteans, and other
dependents or allies of the Egyptian monarch, that
they immediately fubmitted. Nothing now remained
but to difpofe of the captive king, and revenge on him
and his fuhjecls the cruelties which they had commit¬
ted. This the mercilefs victor executed in the feverelt
manner. On the 10th day after Memphis had been
taken, Pfammenitus and the chief of the Egyptian no¬
bility were ignominioufly fent into one of the fuburbs
of that city. The king being there feated in a pro¬
per place, faw his daughter coming along in the habit
of a poor Have with a pitcher to fetch water from the
river, and followed by the daughters of the greatefl:
families in Egypt, all in the fame miferable garb, with
pitchers in their hands, drowned in tears, and loudly
bemoaning their miferable fltuation. When the fathers
fawr their daughters in this diftrefs, they burft into tears,
all but Pfammenitus, vdio only call his eyes on the
ground and kept them fixed there. After the young
women, came the fon of Pfammenitus, with 2000 of
the young nobility, all of them with bits in their mouths
and halters round their necks, led to execution. This
was done to expiate the murder of the Perfian herald
and the Mitylenean failors 5 for Cambyfes caufed ten
Egyptians of the firfl rank to be publicly executed for
every one of thofe that had been ilain. Pfammenitus,
however, obferved the fame conduft as before, keep¬
ing his eyes ftedfaftly fixed on the ground, though all
the Egyptians around him made the loudeft lamenta¬
tions. A little after this he faw an intimate friend and
companion, now advanced in years, wdio having been
plundered of all he had, was begging his bread from
door to door in the fuburbs. As foon as he faw this
man, Pfammenitus wept bitterly •, and calling out to
him by his name, ftruck himfelf on the head as if he
had been frantic. Qf this the fpies wrho had been fet
over him to obferve his behaviour, gave immediate no¬
tice to Cambyfes, who thereupon fent a meflenger to
inquire the caufe of fuch immoderate grief. Pfamme¬
nitus anfwered, That the calamities of his own family
confounded him, and were too great to be lamented by
any outwards figns of grief*, but the extreme diftrefs
of a bofom friend gave more room for reflection, and
therefore extorted tears from him. WTith this anfwer
Cambyfes was fo affe&ed, that he fent orders to pre¬
vent the execution of the king’s fon •, but thefe came Egypt,
too late, for the young prince had been put to death —v'—^
before any of the reft. Pfammenitus himfelf was then
fent for into the city, and reftored to his liberty : and
had he not fhowred a defire of revenge, might perhaps
have been trufted with the government of Egypt: but
being difeovered hatching fchemes againft the go¬
vernment, he wras feized, and condemned to drink
bull’s blood. .,4
The Egyptians were now reduced to the loweft de-Egypt be.
gree of flavery. Their country became a province ofcomfs a
the Perfian empire : the body of Amaifi•> their late king
was taken out of his grave •, and after being mangled an(j after_ ’
in a fhocking manner was finally burnt. But w hat wards of
feemed more grievous than all the reft, their god Apisthf Greciaa
was flain, and his priefts ignominioufly fcourged ; andemPire‘
this infpired the whole nation with luch a hatred to
the Periians, that they could never afterwards be re¬
conciled to them. As long as the Perfian empire fub-
fifted, the Egyptians could never lhake off their yoke.
They frequently revolted indeed, but were always over-
throwm with prodigious lofs. At laft they fubmitted,
without oppofition, to Alexander the Great: after
his death, Egypt again became a powerful kingdom j
though lince the conqueft of it by Cambyfes to the
prefent time it hath never been governed but by fo¬
reign princes, agreeable to the prophecy of Ezekiel.
“ There ihall be no more a prince of the land of E-
gypt” 25
On the death of Alexander the Great, Egypt, to- \fligned to
gether with Libya, and that part of Arabia which Ptolemy
borders on Egypt, were afligned to Ptolemy Lagus as ;uVmres'the
governor under Alexander’s Ion by Roxana, who was t;t]e 0f
but newly born. Nothing was farther from the inten-king.
tion of this governor, than to keep the provinces in
truft for another. He did not, however, affume the
title of king, till he perceived his authority fo firmly
eftabliftied that it could not be lhaken , and this did
not happen till 19 years after the death of Alexander,
when Antigonus and Demetrius had unfuccefsfully at¬
tempted the conqueft of Egypt.
From the time of his firft eftabliftiment on the throne,
Ptolemy, who had affumed the title of Soter, reigned
20 years *, which added to the former 19, make up the
39 years which hiftorians commonly allow him to have
reigned alone.—In the 39th year of his reign, he made
one of his fons, named Philadelphus, partner to the em¬
pire j declaring him his fucceffor, to the prejudice of his
eldeft fon named Ceraunus; being excited thereto by
his violent love for Berenice Philadelphus’s mother.
When the fucceflion was thus fettled, Ceraunus imme¬
diately quitted the court 5 and fled at laft into Syria,
where he was received with open arms by Seleucus Ni-
cator, whom he afterwards murdered.
The molt remarkable tranfadtion of this reign was
the embellifhing of the city of Alexandria, which Pto¬
lemy made the capital of his new* kingdom, and of which
an account is given under the article Alexandria.
About 284 years before Chrift, died Ptolemy Soter,.
in the 41ft year of his reign, and 84th of his age. He
was the beft prince of his race •, and left behind him
an example of prudence, juftice, and clemency which
few of his fucceffors chofe to follow. Befides the pro¬
vinces originally afligned to him, he added to his
empire thofe of Coelo-Syria, Ethiopia, Pamphylia,
Lycia,
■JEgyPtr
.6
Succeeded
by Fhila-
delphus.
17
Ptolemy
Eueigetes
a git at con
queiOF.
E G Y [
Lycia, Carla, and fome of the Cyclades. His fuc-
ceffar, Ptolemy Philadelphus, added nothing to the
extent of the empire i nor did he perform any thing
worthy of notice except embelliflung further the city
pf Alexandria, and entering into an alliance with the
Romans. In his time, one Magas, the goveimr oi
Libva and Cyrene, revolted : and held thefe provinces
as an independent prince, notwithHanding the utmo
efforts of Ptolemy to reduce hum At lail an accom¬
modation took place J and a marriage was ProP^d be¬
tween Berenice, the only daughter of Magas, and Pt -
lemy’s eldeft fon. The young prmcefs was to recede
all her father’s dominions by way of dowry, and thus
they would again be brought under the dominion of
Ptolemy’s family. But before this treaty could be
put in execution, Magas died > and then Apamea the
princefs’s mother, did all ftie could to prevent tbe
match. This, however, Ihe was not able to d°, though
her efforts for that purpofe produced a deftrucbve w
of four years continuance with Antiochus Theus k g
of Syria, and the afting of a cruel tragedy m the fa¬
mily of the latter. See Syria. .
About 246 years before Chnft, Pto emy i a _
phus died j and was fucceeded by his eldeft fon Pt -
my, who had been married to Berenice, the daughter
of Magas as above related. In the beginning of his
reign, he found himfelf engaged m a war with Anti -
thus Theus king of Syria. From this he returned
viaorious, and brought with him 2500 ^tues a
pidures, among which were many of the ancient Lgyp-
tian idols, which had been carried away by Cambyfes
into Perfia. Thefe were reftored by Ptolemy to their
ancient temples ; in memory of which favour, the
Egyptians gave him the furname of Euergetes, or t _c
Beneficent. In this expedition he greatly enlarged is
dominions, making himfelf mailer of all the countries
that lie between Mount Taurus and the confines of
India. An account of thefe conquefts was given by
himfelf, infcribed on a monument, _ to the following
effea. “ Ptolemy Euergetes, having received from
his father the fovereignty of Egypt, Libya, Syria,
Phoenice, Cyprus, Lycia, Cana, and the other Cyclades
affembled a mighty army of horfe and foot, with a great
fleet, and elephants, out of Trogloditia and Ethiopia ,
fome of which had been taken by his father, and the
reft by himfelf, and brought from thence, and trained
up for war: with this great force he failed into Afia j
F . . Jill -1,^ which llC OU
w 1 E G Y
money, and defired him to acquaint the Jews that he _
would make war upon them in cafe of a reumil A
young man, however, named Jofepb, nephew to O-
nias, not only found means to avert the king s anger
but even got himfelf chofen his receiver general, and
by his faithful difcharge of that important trull, con¬
tinued in high favour with Ptolemy as long as he
Ptolemy Euergetes having at laft concluded a peace
with Seleucus the fucceffor of Antiochus. I hens king
of Svria, attempted the enlargement of his dominions
on the fouth fide. In this he was attended with fuch
fuccefs, that he made himfelf mailer of all the coafts. ot
the Red fea, both on the Arabian and Ethiopian
fides, quite down to the ftraits of Babemrandel. On
his return he was met by ambaffadors from the Achle¬
ans, imploring his afliftance again!! the Etohans and
Lacedemonians. This the king readily promifed them .
but thev having in the mean time engaged Antigonus
king of Macedon to fupport them, Ptolemy was io
much offended, that he fent powerful fuccours to Cleo-
menes king of Sparta 5 hoping, by that means., to
humble both the Achieans and their new ally AnUgo-
Egypt.
2S
humble both me ' j A fleomenea
nus. In this, however, he was difappomted j for Cleo-Cleome
roenes, after having gamed very confiderable advan-s_)artatak£r5
tages over the enemy, was at laft entirely deteated tn refuge in
the battle of Sellafia, and obliged to take refuge m Egypt.
Ptolemy’s dominions. He was received by the Egyp¬
tian monarch with the greateft demonilrations of kmd-
nefs ; a yearly penfion of 24 talents was afligned him,
with a promife of reftoring him to the Spartan throne ,
but before this could be aceomphihed, the king oi E- ■
gypt died, in the 27th year of his reign,, and was luc-
ceeded by his fon Ptolemy Philopater. .
Thus we have feen the Egyptian empire brought to •
a very great height of power 5 and had the fucceeding
monarchs been careful to preferve that ftrength of em¬
pire tranfmitted to them by Euergetes,- it is verjf pro¬
bable that Egypt might have been capable of holding^
the balance aga5nft Rome’ and afte^ def^UCh0n °f
Carthage prevented that haughty city from becoming
miftrefs of the world. But after the death of Ptolemy
Euergetes, the Egyptian empire, being governed only
bv weak or vicious monarchs, quickly declined, and
from that time makes no confpicuous figure m hiftory.
Ptolemy Philopater began his reign vath the murder P o emy
of his brother •, after which, giving lumfeif up to -11^^
r   lUoCf Irincnrlom fell into a kind ,
up for war1: with this great force he failed into Afia^ ^^Xn^ntioufiieft,1 the kingdom fell into a kind ^ ty'
and having conquered all Ae . the o{ anarchy. Cleomenes the Spartan king ftill refided
and na\ing conqucicu - . ,
this fide the Euphrates, Cilicia, Pamphylia, Ioma> th^
Hellefpont, and Thrace, he croffed that river with all
the forces of the conquered countries, and the king*
of thofe nations, and reduced Mefopotamia, Bab> Io¬
nia, Sufiana, Perfia, Media, and all the country as iar
as Ba<5tna« # ■* /y* i
On the king’s return from this expedition, he palled
through Jerufalem, where he offered many facnfices
to the God of Ifrael, and ever afterwards expreffed a
11 real favour for the Jewiflr nation. At tins tune, the
Jews were tributaries to the Egyptian monaichs, and
paid them annually 20 talents of .filver. 1 his. tribute,
however, Onias, who was then high pneft, being of a
very covetous difpofition, had for a long time neglected
to pay, fo that the arrears amounted to a very large
fum. Soon after his return, therefore, Ptolemy fent
one of his courtiers named Athenian to demand , the
of anarchy. Cleomenes the Spartan king ftill refided
at court j and being now unable to bear the diflolute
manners which prevailed there, he p.reffed Philopater.
to give him the afliftance he had prormled for reftormg
him to the throne of Sparta. This he the rather in¬
filled upon, becaufe he had received advice that Anti¬
gonus king of Macedon was dead,, that the Achseans
were engaged in a war with the Etohans, and that the
Lacedemonians had joined the latter agamft the Aclne-
ans and Macedonians. Ptolemy, when atraid ot Ins
brother Magas, had indeed promifed to afliit the king
of Sparta with a powerful fleet, hoping by this means
to attach him to his own intereft', but now when Magas
was out of the way, it was determined by the king, or
rather his minifters, that Cleomenes fliould not be af-
fifted, nor even allowed to leave the kingdom ; and
this extravagant refolution produced the defperan.^-
Egypt.
E G Y [ 598
'Jhehiftor^f SPARTA^ Kh,Ch anaCC°Um “ ^ “
Of the diforders which now enfued in the govern¬
ment, Antiochus king of Syria, furnamed the Great
took the advantage, and attempted to wreft from Pto-
lemy the provinces of Coelo-Syria and Paleftine. But
in this he was finally disappointed j and might eafily
have been totally driven out of Syria, had not Ptolemy
been too much taken up with his debaucheries to think
of carrying on the war. The difeontent occafioned by
this piece of negligence foon produced a civil war in
ns dominions and the whole kingdom continued in
the utmoft confufion till his death, which happened in
the 17th year of his reign and 37th of his are
During the reign of Philopater happened a very ex-
eoncerning traor?Inary .event wdth regard to the Jews, which‘is
the Jews, mentioned in the Maccabees *. The king- of Ervnt
*Lib. i,i. 2. while on his Syrian expedition, had attempted to en-
ter the temple of Jerufalem j but being hindered by
t e Jews, he was filled with the utmoif rage againft
the whole nation On his return to Alexandria, he
reiolved to ma^e thofe who dwelt in that city feel the
]
E G Y
30
sExtraordi-
nary itory
3, 4. 5-
firft efFeds of his vengeance. He began with publilhing
a decree, which he caufed to be engraved on a pillar
erefted for that purpofe at the gate of his palace, ex-
cluding all thofe who did not facrifice to the gods wor-
ihipped by the king. By this means the Jews were
debarred from fuing to him for juftice, or obtaining
his protection when they happened to hand in need of
it. By the favour of Alexander the Great, Ptolemy
Soter, and Euergetes, the Jews enjoyed at Alexandria
the lame privileges with the Macedonians. In that
metropolis the inhabitants were divided into three
ranks or claffes. In the firlt were the Macedonians,
or original founders of the city, and along with them
were enrolled the Jews j in the fecond were the mer-
cenanes who had ferved under Alexander: and in
the third native Egyptians. Ptolemy now, to
be revenged of the Jews, ordered, by another decree,
that they fliould be degraded from the firft rank, and
enrolled among the native Egyptians. By the fame
decree it was enafted, that all of that nation ftiould ap¬
pear at an appointed time before the proper officers, in
order to be enrolled among the common people : that
at the time of their enrollment they ffiould have the
wftbk°h -^W^e of Bacchus, impreffed
maAe^ffi 'TA™ th,eir/aces 5 that all who were thus
me ffid m°nld made fl-aVeS ’ and» la%* that if any
one ffiould ftand out againft this decree, he ffiould be
immediately put to death. That he might not, how-
tw’tW™ ln rnem/ t? the whole nation* he declared,
that thofe who facrfficed to their gods ffiould enjoy their
former privileges, and remain in the fame clafs. Yet
notwithftandmg this tempting offer, 300-only out of
many thoufand Jews who lived in Alexandria could be
prevailed, upon to abandon their religion in order to
lave themfelves from Ha very.
tl Th® aP°ftates V’ere immediately excommunicated by
heir brethren and this their enemies conftrued a^
done m oppofition to the king’s order 5 which threw
,he tyrant into fuch a rage, that he refolved to extir-
pate the whole nation, beginning with the Jews who
lived in Alexandria and other cities of Esjypt and
proceeding from thence to Judaea and Jerufalem itfelf.
^n coniequence of this cruel refolution, he commanded
1
ad the Jews that lived in any part of Egypt to he
brought in chains to Alexandria, and there to be fhut
up m the Hippodrome, which was a very fpacious
place without the city, where the people uied to af-
iemble to fee horfe races and other public diverfions.
x le then fent for^ Herman mafter of the elephants ■
and commanded him to have 500 of thefe animals ready
againft the next day, to let loofe upon the Jews in the
ippodrome. But when the elephants were prepared
for the execution, and the people were affembled in
great crowds to fee it, they were for that day dhap-
pointed by the king’s abfence. For, having been late
up the night before with fome of his debauched com¬
panions, he did not awake till the time for the fliow
was over, and the fpeftators returned home. He
therefore ordered one of his fervants to call him early
on the following day, that the people might not meet
with a lecond difappomtment. But when the perfon
awaked him according to his order, the king was not
yet returned to his fenfes -y having withdrawn, exceed¬
ingly drunk, only a fliort time before. As he did not
remember the order, he therefore fell into a violent
%>’!*•
  ..v- icii iiuo a violent
paliion, and threatened wdth death the fervant who had
awaked him ; and this caufed the ffiow to be put off
till the third day. At laft the king came to the Hip¬
podrome attended with a vaft multitude of fpeftators:
but when the elephants were let loofe, inftead of falll
ing upon the Jews, they turned their rage againft the
ipectators and foldiers,.and deftroyed great numbers of
^ ^ ^ame Gme? fome frightful appearances
which were feen in the air fo terrified the king, that he
commanded the Jews to be immediately fet at liberty
and reftored them to their former privileges. No fooner
were they delivered from this danger than they de¬
manded leave to put to death fuch of their nation as
had abandoned their religion j and this being granted,
t ley defpatched the apoftates without excepting’ a An¬
gle man. 0
Philopater was fucceeded by Ptolemy Epiphanes 5 Ptolemy
and he, after a reign of 24 years, by Ptolemy Philo-Philometor
metor. In the beginning of his reign, a war com-taken Pri-
menced with the king of Syria, who had feized on thefone.rlY
provinces of Coelo-Syria and Paleftine in the preceding
mgn. In the courfe of this wrar, Philometer was ei-conraifed
ther voluntarily delivered up to Antiochus or taken toffie
priloner. But however this was, the Alexandrians de-chrontu
Ipainng of his ever being able to recover his liberty,
railed to the throne his brother Ptolemy, wffio took the
name of Euergetes II. but was afterwards called Phyfcon
or ‘‘ the great-bellied,” on account of the prominent
belly which by his gluttony and luxury he had acquir¬
ed. He was fcarce feated on the throne, however,
when Antiochus Epiphanes, returning into Egypt
drove out Phyfcon, and reftored the whole kingdom
except Pelufium,. to Philometor. His defign was to
kindle a war betwixt the two brothers, lb that he might
have an opportunity of feizing the kingdom for him-
felf. For this reafon he kept to himfelf the city of
Pelufium ; which being the key of Egypt, he might at
his pleafure re-enter the country. But'Philometor, ap-
pnfed of his defign, invited his brother Phyfcon to an
accommodation 5 which was happily effeefted by their
filter Cleopatra. In virtue of this agreement, the bro¬
thers were to reign jointly, and to oppofe to the utmoft
01 their poi\ er Antiochus, whom they conlidered as a
common
Egypt.
33
Difference
between
the two
brothers
decided by
the Roman
fenate.
E G Y [ 599 1 E G ^ f ,
On this the king of Syria invaded Phyfcon dropped all thoughts of Cyprus for the pre-
1 ’ 1 fent ; and haftened with all his forces to Cyrene, where
34
liland of
Cyprus ad¬
judged to
Phyfcon.
35
Philometer
refutes to
co .n ply.
Rebellion
againft
Phyfcon.
common enemy.   - - 0
Egypt with a mighty army, but was prevented by the
Romans from conquering it.
The two brothers were no {boner freed from the ap-
prehensions of a foreign enemy than they began to
quarrel with each other* Their differences foon came
to fuch a height, that the Roman fenate interpofed.
But before the ambaffadors employed to inquire into
the merits of the caufe could arrive in Egypt, 1: hyfcon
had driven Philometor from the throne, and obliged
him to quit the kingdom. On this the dethroned
prince fled to Rome, where he appeared meanly drefs-
ed, and without attendants. He was very kindly re¬
ceived by the fenate •, who were fo well fatisfied of the
injuflice done him, that they immediately . decreed his
reftoration. He was reconducfed accordingly; and,
on the arrival of the ambaffadors in Egypt, an accom¬
modation between the two brothers was negotiated.
By this agreement, Phyfcon was put in poffeffion of
Libya and Cyrene, and Philometor of all Egypt and
the iiland of Cyprus; each of them being declared in¬
dependent of the other in the dominion allotted to
them. The treaty, as ufual, was confirmed with oaths
and facrifices, and was broken almoit as foon as. made.
Phyfcon was diffatisfied with his fhare of the dominions }
and therefore fent ambaffadors to Rome, defiring that
the ifland of Cyprus might be added to his other pof-
feffions. This could not be obtained by the ambaffadors j
and therefore Phyfcon went to Rome in perfon. His
demand was evidently unjuft j but the Romans, confi-
denng that it was their intereft to weaken the power
of Egypt as much as poftible, without further ceremo¬
ny adjudged the ifland to him.
" Phyfcon fet out from Rome with two ambaffadors *,
and arriving in Greece on his way to Cyprus, he raffed
there a great number of mercenaries, with a d.efign to
fail immediately to that iftand and conquer it. But
the Roman ambaffadors telling him, that they were
commanded to put him in poffeffion of it by fair means
and not by force, he difmiffed his army, and returned
to Libya, while one of the ambaffadors proceeded to
Alexandria. Their defign was to bring the two bro¬
thers to an interview on the frontiers of their domi¬
nions, and there to fettle matters in an amicable man¬
ner. But the ambaffador who went to Alexandria,
found Philometor very averfe from compliance with the
decree of the fenate. He put oft the ambaffador lo
long, that Phyfcon fent the other alfo to Alexandria,
hoping that the joint perfuaftons of the two would in¬
duce Philometor to comply. But the king, after en¬
tertaining them at an immenfe charge for 40 days, at
laft plainly refufed to fubmit, and toid the ambaffadors
that he was refolved to adhere to the firft treaty. With
this anfwer the Roman ambaffadors departed, and were
followed by others from the two brothers. The fenate,
however, not only confirmed their decree in favour of
Phyfcon, but renounced their alliance with Pnilome-
tor, and commanded his ambaffador to leave the city
in five days.
In the mean time, the inhabitants of Cyrene having
heard unfavourable accounts of Phyfcon’s behaviour
during the ftiort time he reigned in Alexandria, con¬
ceived fo ftrong an averfion againft him, that they re¬
folved to keep him out of their country by force of
arms. On receiving intelligence of this refolution,
Egypt.-
—^—
he foon got the better' of his rebellious iubjecfts, and
eftabliftied himfelf in the kingdom. His vicious and
tyrannical conduct, however, foon eftranged from him
the minds of his fubje£ts, in fuch a manner, that fome
of them entering into a confpiracy againft him, fell
upon him one night as he was returning to his palace,
wounded him in feveral places, and left him for dead
on the fpot. This he laid to the charge of his bro¬
ther Philometor j and as foon as he was recovered, took
another voyage to Rome. Here he made his com¬
plaints to the fenate, and {bowed them the fears of his
wounds, acculing his brother of having employed the
affaftins from whom he received them. 1 hough Phi¬
lometor was known to De a man of a moft humane and
mild difpofition, and therefore very unlikely to have
been concerned in io biack an attempt j yet the lenate,
being offended at his refufing to fubmit to their decree
concerning the ifland of Cyprus, heancened to this falle
accufation j and carried their prejud ee io far, that they
not only refufed to hear what his ambaffadors had to lay,
but ordered them immediately to depart from the city.
At the fame time, they appointed five commiffioners to
conduct Phyfcon to Cyprus, and put him in pofleflion
of that ifland, enjoining all their allies in thofe parts to ■
fupply him with forces for that purpofe.
Phyfcon having by this means got together an army
which feemed to him to be lufticient lor the accom-
plifliment of his delign, landed in Cyprus p but being
there encountered by Philometor in perfo.n, he.was
entirely defeated, and obliged to (belter himfelf in a
city called Lapitho. Here he was clofely befteged, and ^
at laft obliged to furrender. Every one now expe&ed He is de-
that Phyfcon would have been treated as he deferved 5 feated and
but his brother, inftead of puniihing, reftored him to ^ Pn*
the government of Libya and Cyrene, adding fome
other territories inftead of the iftand of Cyprus, and
promifing him his daughter in marriage. Thus an
end was put to the war between the two brothers $ for
the Romans were aftiamed any longer to oppofe a prince
who had given fuch a fignal inftance of his juftice and
clemency. # # .
On his return to Alexandria, Philometor appointed
one Archias governor of Cyprus. But he, foon after
the king’s departure, agreed with Demetrius king of
Syria, to betray the iftand to him for 500 talents.-
The trenchery was difcovered before it took effect j and
the traitor, to avoid the punilhment due to his crime,
laid violent hands on himfelf. Ptolemy being offended
with Demetrius for this attempt on Cyprus, joined At¬
tains king of Pergamus, and Anarathes king ot Cap¬
padocia, in fetting up a pretender to the crown of Sy¬
ria. This was Alexander Balas 5 to whom he even gave
his daughter Cleopatra in marriage, after he had placed
him on the throne of Syria. But he, notwithftanding
thefe and many other favours, being fufpe£ted of having-
entered into a plot againft his benefaftor, Ptolemy be¬
came his greateft enemy j and marching againft him,
routed his army in the neighbourhood of Antioch. -g
He did not, however, long enjoy his vidory j for he Death of
died in a few days after the engegement, of the v/ounds Prftom.
he had received.
On the death of Philometor, Cleopatra the queen
defigned to fecure the throne for her ion. But fome.
E G Y
39
Monftrous
-wickednefs
40
He is driv
.en out#
^gypt- , of the principal nobility declaring for Phyfcon, a civil
v war was about to enfue, when matters were compro-
mifed on condition that Phyfcon lliould marry Cleo¬
patra, that he fhould reign jointly with her during his
life, and declare her fon by Philometor heir to the
wicKeoneis crown' Thefe terms were no fooner agreed upon than
of Phyfcon. Phyfcon_married Cleopatra, and, on the very day of
,the nuptials, murdered her fon in her arms. This was
only a prelude to the cruelties which he afterwards
prachifed on his lubjedts. He was no fooner feated on
the throne, than he put to death all thofe who had
Jhown any concern for the murder of the young prince.
He then wreaked his fury on the Jew’s, whom he
treated more like Haves than fubjefts, on account of
their having favoured the caufe of Cleopatra. His own
people were treated with little more ceremony. Num¬
bers of them were every day put to death for the fmalL
^elf faults, and often for no fault at all, but merely to
gratify his inhuman temper. His cruelty towards the
Alexandrians is particularly mentioned under the ar¬
ticle Alexandria. In a Ihort time, being v’earied of
his queen, who was alfo his filler, he divorced her •, and
married her daughter, who was alfo called Cleopatra,
- and whom he had previoufly ravilhed. In Ihort, his
behaviour was fo exceedingly wicked, that it foon be¬
came quite intolerable to his fubjefts ; and he was obli¬
ged to dy to the illand of Cyprus with his new queen,
and Mempliitis, a fon he had by her mother.
On the flight of the king, the divorced queen was
placed on the throne by the Alexandrians4 but Phyfcon,
fearing left a fon whom he had left behind.fhould be ap¬
pointed king, fent for him into Cyprus, and caufed him
to be affaflinated as foon as he landed. This provoked
the people againft him to fuch a degree, that they pulled
dowrn and dallied to pieces all the ftatues which had been
erefted to him at Alexandria. This the tyrant fuppofed
to have been done at the inftigation of the queen, and
therefore refolved to revenge it on her by killing his
own fon whom he had by her. He therefore, without
the leaft remorfe, caufed the young prince’s throat to
be cut j and having put his mangled limbs ipto a box,
fent them as a prefent to his mother Cleopatra. The
melfenger with whom this box v’as fent, was one of his
guards. He w’as ordered to wait till the queen’s birth¬
day, which approached, and was to be celebrated with
extraordinary pomp •, and in the midft of the general
.rejoicing, he was to deliver the prefent.
1 he horror and deteftation occafioned by this un¬
exampled piece of cruelty cannot be exprefled. An
army was foon raifed, and the command of it given to
one Marfyas, whom the queen had appointed general,
and enjoined to take all the neceffary flops for the de¬
fence of the country. On the other hand, Phyfcon,
having hired a numerous body of mercenaries, fent
them, under the command of one Hegelochus, againft
the Egyptians. The two armies met on the frontiers
of Egypt, on which a bloody battle enfued ; but at
laft the Egyptians were entirely defeated, and Marfyas
was taken prifoner. Every one expected that the cap¬
tive general u’ould have been put to death with the fe-
vereit torments j but Phyfcon, perceiving that his cru¬
elties only exafperated the people, refolved to try whe¬
ther he could regain their affeftions by lenity; and
therefore pardoned Marfyas, and fet him at liberty 
Cleopatra, in the mean time, being greatly diftreffed
a
[ 600 ] E G Y
by tins overthrow, demanded afliftance from Deme¬
trius king of Syria, who had married her eldeft daugh¬
ter by Philometor, promifing him the crown of Egypt
for his reward. Demetrius accepted the propofal
without hefitation, marched with all his forces into E-
gypt, and there laid fiege to Pelufium. But he beinu-
no lefs hated in Syria than Phyfcon wras in Egypt, the
people of Antioch, taking advantage of his abfence,
revolted againft him, and were joined by moft of the
other cities in Syria. Thus Demetrius was obliged to
return; and Cleopatra, being now in no condition to
4i
Murders
his Ion.
oppofe Phyfcon, fled to Ptolemais, where her daughter PHyicon re¬
tire queen of Syria at that time refided. Phyfcon was ftoreth
then reftored to the throne of Egypt, which he enjoy¬
ed without further moleftaticn till his death; which
happened at Alexandria, in the 29th year of his reign
and 67th of his age. - ’
To Phyfcon fucceeded Ptolemy Lathyrus, about
122 years before Clirift 5 but he had" not reigned lonrq
before his mother, finding that he would not be entirely
governed by her, by falfe furmifes ftirred up the Alex-
andrians, who drove him from the throne, and placed Ptolemy
on it his youngeft brother Alexander. Lathyrus after Lathyrus
this was obliged to content himfelf with the govern-
ment of Cyprus, which he was permitted to enjoy in ander fet"
quiet. Ptolemy Alexander, in the mean time, finding up.
he was to have only the ihadow of fovereignty, and
that his mother Cleopatra w'as to have all the power,
ftole away privately from Alexandria. The queen ufed
every artifice to bring him back, as well knowing that
the Alexandrians would never fuller her to reign alone.
At laft her fon yielded to her entreaties ; but foon af¬
ter, underftanding that Hie had hired aflaflinsto defpatch
him, he cauled her to be murdered. ^
The death of the queen was no fooner known to the Lathyius
Alexandrians, than, difdaining to be commanded by reltored.
a parricide, they drove out Alexander, and recalled La¬
thyrus.— Phe depofed prince for fome time led a ram¬
bling life in the illand of Cos 5 but having got toge¬
ther fome Ihips, he, the next year, attempted to return
into Egypt. But being met by Tyrrkus, Lathyrus’s
admiral, he was defeated, and obliged to fly to Myra
in Lycia. From Myra he fleered his courfe towards
Cyprus, hoping that the inhabitants would place him
on the throne, inltead of his brother. But Choreas,
another of Lathyrus’s admirals, coming up with him
while he was ready to land, an engagement enfued, in
which Alexander’s fleet was difperfed, and he himfelf
killed. ^
During thefe difturbances, Apion king of Cyrenaica, Cyreuaica
the fon of Ptolemy Phyfcon by a concubine, having bequeathed
maintained peace and tranquillity in his dominions du-t0.t^e ^t)"
ring a reign of 21 years, died, and by his will leftm‘inb'
his kingdom to the Romans ; and thus the Egyp¬
tian empire was confiderably reduced and circum-
feribed. ^
Lathyrus being now delivered from all competitors, City of
turned his arms againft the city of Thebes, which had T hebes
revolted from him. The king marched in perfonr J
againft the rebels 5 and, having defeated them in a
pitched battle, laid clofe fiege to their city. The in¬
habitants defended themfelves with great refolution for
three years. At laft, however, they were obliged to
fubmit, and the city was given up to be plundered by
the foldiery. They left everywhere the moft melan¬
choly
ruined.
Egypt.
47 ,
Alexander
II. tucceeds
Lathy rus.
48
Marries
Cleopatra,
and mur¬
ders her.
49 .
Leaves his
kingdom
to the Ro¬
mans.
E G Y [60
choly monuments of their avarice and cruelty ’ J° ^
Thebes, which till that time had been one of the mo t
wealthy cities of Egypt, was now reduced fo low that
it never afterwards made any figure.
About 76 years before Chnft, Ptolemy Lat yrus
was fucceeded by Alexander II. He was the on of
the Ptolemy Alexander for whom Lathyrus had oee
driven out; and had met with many adventures. He
was firit fent by Cleopatra into tne ifland of Cos, with
a great fum of money, and all her jewels j as thinking
that was the fafeft place where they could be kept.
When Mithridates king of Pontus made himielt malter
of that iiland, the inhabitants delivered up to him the
young Egyptian prince, together with _ all the tiea-
fures. Mithridates gave him an education fuitable to
his birth •, but he, not thinking himfelf fafe with a
prince who had Ihed the blood of his own children,
fled to the camp of Sylla the Roman dictator who
was then making war in Afia. From that time he li¬
ved in the family of the Roman general, till news was
brought to Rome of the death of Lathyrus. Sylla then
fent him to Egypt to take poffeflion of the throne.
But, before his arrival, the Alexandrians had choien
Cleopatra for their fovereign. To compromiie matters,
however, it was agreed, that Ptolemy ihould marry her,
and take her for his partner in the throne. I his was
accordingly done ; and 19 days after the marriage, the
unhappy queen was murdered by her hulhand, who for
1 c years afterwards fliowed himielf luch a moniter of
wickednefs, that a general infurre&ion at lalt enfued
among his fubjefts, and he was obliged to fly to Pom-
pey the Great, who was then carrying on the war a-
gainft Mithridates king of Pontus. But Pompey
refufing to concern himfelf in the matter, he retired
to the city of Tyre, where he died fome months
after. . - . ,
When he was forced to {hut himfelf up m the city
of Tyre, Alexander had fent rnnbaffadors to Rome, m
order to influence the fenate in his favour. But, y-
ing before the negociation was finiftied, he made over
by his laft will all his rights to the Roman people, de¬
claring them heirs to his kingdom : not out of any a -
fection to the republic } but with a view to raife dis¬
putes between the Romans and his rival Auletes, whom
the Egyptians had placed on the throne. The will
was brought to Rome, where it occafioned warm de¬
bates. Some were for taking immediate poffeiiion of
the kingdom. Others thought that no notice Ihould
be taken of fuch a will, becaufe Alexander had no
naht to difpofe of his dominions in prejudice of his luc-
ceffor, and to exclude from the crown thofe who were
of the royal family of Egypt. Cicero reprelented, that
fuch a notorious impofition would debafe the majefly of
the Roman people, and involve them in endlefs wars
and difputes $ that the fruitful fields, of Egypt would
be a itrong temptation to the avarice of the people,
who would iniift on their being divided among them ;
and laftly, that by this means the bloody quarrels about
the Agrarian laws would be revived. I hefe reafons
tad fome weight with the fenate 5 but what chiefly pre¬
vented them from feizing on Egypt at this time was,
that they had lately taken pofieflion of the kingdom of
Bithynia in virtue of the will of Nicomedes, and of
Cyrene and Libya by the will of Apion. I hey thought,
therefore, that if they fliould, on the like pretence,
'Yol. VII. Part II.
1 j - E G Y
take poffeflion of the Kingdom of Egypt, this might Egypt^
too much expofe their deiign of fettmg up a kind of
univerfal monarchy, and occafion a formida e combi
nation againft them.
Auletes, who was now raifed to the throne by t le ^ A^,ete„
Egyptians, is faid to have furpaffed all the kings that the n£W
went before him in the effeminacy of his manners, lucking,
name Ju/etes, which fignifies xhe flute-player, was giv¬
en him becaufe he piqued himfelf on his Ikiil in per-
foftning upon that inftrument, and was not aihamed
even to contend for the prize in the public games. He
took great pleafure in imitating the manneis of tie
Bacchanals j dancing in a female drefs, and in t e
lame meafures that they ufed during the folemnity c.
their god Bacchus , and hence he had the furname o.
the New Dionyfius or Bacchus. As his title to t is
crown was difputable (he being only the fon o a
concubine), the firft care of Auletes was to get him¬
felf acknowledged by the Romans, and declared their st
ally. This was obtained by applying to J ulius Caiiar, is acknow-
who was at that time conful, and immenfely in debt, bj
Caefar being glad of fuch an opportunity of railing
money, made the king of Egypt pay pretty dear for
his alliance. Six thoufand talents, a fum equal to
1,162,500k Sterling, were paid partly to Cadar him¬
felf, and partly to Pompey, whofe intereft was necef-
fary for obtaining the confent of the people. Though
the revenues of Egypt amounted to twice, this fum,
yet Auletes found it impoflible for him to raife it with¬
out feverely taxing his fubjefts. This occafioned a ge¬
neral difcontent j and while the people were almofl;
ready to take up arms, a molt unjuft decree paffed at
Rome for feizing the iiland of Cyprus. W hen the A-
lexandrians heard of the intentions of the republic, they
preffed Auletes to demand that ifland as an ancient ap¬
pendage of Egypt j and, in cafe of a refufal, to de¬
clare war againil that haughty and imperious people,
who, they now faw, though too late, aimed.at nothing
lefs than the fovereignty of the world. With this re-
queft the king refufed to comply upon which his fub-
je£ts, already provoked beyond meafure at tne taxes js jrjven
with which they were loaded, flew to arms, and fur-from the
rounded the palace. The king had the good luck to throne, and
efcape their fury, and immediately leaving Alexandria,
fet fail for Rome.
In his way to that city, he landed on the ifland of
Rhodes, where the famous Cato at that time was, be¬
ing on his way to Cyprus, to put the unjuft decree of
the fenate in execution. Auletes, defirous to coiner
with a man of his prudence, immediately fent to ac¬
quaint him with his arrival. He imagined, that, up¬
on this notice, Cato would immediately come and wait
upon him j but the proud Roman told the meflenger,
that if the king of Egypt had any thing to fay to Ca¬
to, he might, if he thought proper, come to his houfe.
Accordingly the king went to pay him a vifit j but was
received with very little ceremony by Cato, who did
not even vouchfafe to rife out of his feat when he came 53
into his prefence. When Auletes had laid his affairs _at0 s
before this haughty republican, he was blamed by him
for leaving Egypt, the richeft kingdom in the. world,
in order to expofe himielf, as he laid, to the indigni¬
ties he would meet with at Rome. T here Cato told
him, that nothing was in requeft but wealth and gran¬
deur. All the riches of Egypt, he faid, would not. be
4 G fumcient
E G Y
£4
Infamous
fufKcient to fatisfy the avarice of the leading men In
Rome.. He therefore advifed him to return to E^ypt;
and ft rive, by. a more equitable conduft, to regain the
.iffeclions of his people. He even offered to recondufl
aim tnitlier, and employ his good offices in his behalf.
Eut^ though Ptolemy was fenfible of the propriety
this advice, the friends he had with him diffuaded
rum from following it, and accordingly he fet out for
Rome.
On his arrival in this metropolis, the king found,' to
Auletes. hlS great COncern’ that Caefar; ^ whom he'placed his
greateft confidence, was then in Gaul. Pie was receiv¬
ed, however, by Pompey with great kindnefs. He
affigned him an apartment in his own houfe, and omitted
nothing that lay in his power to ferve him. But, not-
withftanding the prote<ftion of fo powerful a man, Au¬
letes was forced, to go from houfe to houfe like a pri¬
vate perfon, foliciting the votes of the fenators. Af¬
ter he had {pent immenfe treafures in procuring a
ftrong party in the city, he was at laft permitted to
lay his complaints before the fenate 5 and at the fame
time there arrived an embaffy from the Alexandrians,
confining of 100 citizens, to acquaint the fenate with
55 the reafons of their revolt.
ra'fedtTl- ’ ,^len Auletes .firft fet out for Rome, the Alexan-
throneof e ^rians’ not knowing what was become of him, placed
on the throne his daughter Berenice j and fent an em-
baffy intQ Syria to Antiochus Afiaticus, inviting him
into E.gy])t to marry the queen, and reign in partner-
Ihip with her. Antiochus was dead before the arrival
~ . of tne ambaffadors 5 upon which the fame propofal was
Seleiic.us*1CSp;a^e to brother Seleucus, who readily accepted it.
and mur- ^ bis Seleucus is delcnbed by Strabo as monftroully de-
ders him. formed in body, and ftill more fo in mind. The E-
gyptians nicknamed him CybiofaBes, or the Scullion ; a
name which feemed more fit for him than any other.
He was fcarce fettled on the throne, when he gave a
iignal inftance of his fordid and avaricious temper.
' Ptolemy the firft had caufed the body of Alexander the
Great to be depofited in a coffin of maffy gold. This
the king feized upon ; and by that means provoked his
wife Berenice to fuch a degree, that fhe caufed him to
be. murdered. She then married one Archelaus, high
prieft of Comana in Pontus, who pretended to be the
[ 602 ]
E G Y
Egypt.
Egypt.
5*
Marries
Archelaus.
fon of Mithridates the Great ; but was, in faff, only
the fon of that monarch’s general.
Auletes was not a little alarmed on hearing of thefe
tranfadlions, efpecially when the ambaffadors arrived,
which he feared would overturn all the fchemes he had
laboured fo much to bring about. The embaffy was
headed by one Dion, a celebrated Academic philofopher
Ametes W^° kac* many powerful friends at Rome. But Ptolemy
murders the found means to get both him and moft of his followers
Egyptian afiaffinated ; and this intimidated the reft to fuch a de¬
gree, that, they durft not execute their commiffion, or,
for.fome time, even demand juftice for the murder of
their colleagues.
The report of fo many murders, however, at lafl:
fpreaft a general alarm. Auletes, fure of the protec¬
tion of Pompey, did not fcruplg to own himfelf the
perpetrator of them. Nay, though an adlion was
commenced againft one Afcitius, an affaffin, who had
{tabbed Dion the chief of the embaffy above mentioned,
and the -crime was fully proved j yet he was acquitted
58
Auletes
ambaffa
dors.
59
by the venal judges, who had all been bribed by Pto-
lemy. . In a ffiort time, the fenate paffed a decree, by
which it was ena&ed, that the king of Egypt fhould
be reftored by force of arms. All the great men in His reftora-
Kome were ambitious of this commiffion 5 which, they tiondecreed
well, knew, xvould be attended with immenfe profit, by the fe»
Iheir contefts on this occafion took up a confidcrablenate>
time ; and at laft a prophecy of the Sybil was found
out, which forbade the affifting an Egyptian monarch
wuth an army. Ptolemy, therefore, wearied out with fo
long a delay, retired from Rome, where he had made
himtelf generally odious, to the temple of Diana at
Epheius, there to xvait the decifion of his fate. Here
he remained a confiderable time : but as he faw that the
lenate came to no refolution, though he had folicited
them by letters, fo to do; at laft, by Pompey’s advice, he
applied to Gabinius the proconful of Syria. This Gabi-
nius was a man of a moft infamous chara&er, and ready
to undertake any thing for money. Therefore, though
it was contrary to an exprefs lawT for any governor to
go out of his province without pofitive orders from the
enate and people of Rome, yet Gabinius ventured to
tranfgrefs. this law, upon condition of being well paid
for his pains. As a recompenfe for his trouble, how'- r 6a-
ever, he demanded 10,000 talents; that is, .,937,500!. ..ndmX,
iterimg. Ptolemy, glad to be reftored on any terms, to reltore
agreed to pay the above-mentioned fum ; but Gabiniusfor a
xvould not ftir till he had received one half of it. This §rea,: fum*
obliged the king to borrow- it from a Roman knight
named Cams Rabinus Pq/Ihunuus ; Pompey interpofing
his credit and authority for the payment of the capital
and intereft.
Gabinius now fet out for Egypt, attended by the
famous Mark Antony, xvho at this time ferved in the
army under him. He w^as met by Archelaus, wffio
fince the departure of Auletes had reigned in Egypt
jointly with Berenice, at the head of a numerous army.
I he Egyptians were utterly defeated, and Archelaus
taken prifoner in the firft engagement. Thus Gabi¬
nius might have put an end to the w-ar at once : but
his avarice prompted him to difmifs Archelaus on his
paying a confiderable ranfom ; after which, pretending
that he had made his efcape, freffi fums w-ere demanded
from Ptolemy for defraying the expences of the war.
For .thefe fums Ptolemy xvas again obliged to apply to
Rabirius, who lent him what money he wanted at a 61
very high intereft:. At laft, hoxvever, Archelaus w-as Arctalaus
defeated and killed, and thus Ptolemy again became Seated
mafter of all Egypt. and kiiled*
No fooner was Auletes firmly fettled on the throne, R 6?
than he put to death his daughter Berenice, and op-
preffed his people wdth the moft cruel exadlions, in or-death and
der to procure the money he had been obliged to hor-the people
row while in a ftate of exile. Thefe oppreffions and °PPre^ed.
e.xaftions the coxvardly Egyptians bore with great pa¬
tience, being intimidated by the garrifon which Gabi¬
nius had left in Alexandria. But neither the fear of
the Romans, nor the authority of Ptolemy, could make
them put up an affront offered to their religion. A
Roman foldier happened to kill a cat, which w-as an
animal held facred and even worfliipped by the Egyp¬
tians ; and no fooner was this fuppofed facrilege knowm,
than the Alexandrians made a general infurre&ion,
and, gathering together in croxvds, made their way
through
E G Y
t 603 . ]
E G Y
Egypt.
through the Roman guards, dragged the foldier out of
' his houfe, and, in fpite of all oppofition, tore him m
Egypt*
pieces.
Notwithftanding the heavy taxes, however, which
Ptolemy laid on his people, it doth not appear that
he had any defign of paymg his debts. Rabirius, »\ho,
63 as we have already obferved, had lent him immenfe
Ingratitude fums, finding that the king affetfed delays, took a
of Auletes. VOyage to Egypt, in order to expoftulate with him m
perfon. Ptolemy paid very little regard to his expoftu-
lations *, but excufed himfelf on account of the bad
ftate of his finances. For this reafon he offered to
make Rabirius colleftor general of his revenues, that
he might in that employment pay himfelf. The unfor¬
tunate creditor accepted the employment for fear of
lofmg his debt. But Ptolemy, foon after, upon fome
frivolous pretence or other, caufed him and all his fer-
vants to be clofely confined. Ibis bafe conduft exaf-
perated Pompey as much as Rabirius j for the former
had been in a manner fecurity for the debt,- as tire mo¬
ney had been lent at his requeft, and the bufinefs trani-
ailed at a country houfe of his near Alba. However,
as Rabirius had reafon to fear the worfl, he took the
firft opportunity of making his efcape, glad to get otf
with life from his cruel and faithlefs debtor. To com¬
plete his misfortunes, he was profecuted at Rome as
foon as he returned, 1. For having enabled Ptolemy
to corrupt the fenate with fums lent him for that pur-
pofe. 2. For having debafed and diihonoured the cha-
railer of a Roman knight, by farming the revenues,
and becoming the fervant of a foreign prince. 3. For
having been an accomplice with Gabinius, and iharing
with him the 10,000 talents rvhich that proconful had
received for his Egyptian expedition. By the elo¬
quence of Cicero he was acquitted •, and one of the
beft orations to be found in the writings of that author
was compofed on this occafion. Gabinius was ailo pro¬
fecuted } and, as Cicero fpoke againft him, he very nar¬
rowly efcaped death. He was, however, condemned to
perpetual banifhment, after having been ftripped of all
he wras worth. He lived in exile till the time of the
civil wars, when he was recalled by Caefar, In whofe
- fervice he loft his life.
Leaves his Auletes enjoyed the throne of Egypt about four
children to years after his re-eftabliftunent } and at his death left
the care of children, a fon and two daughters, under the tui-
Rf,- £jon of the Roman people. The name of the fon was
Ptolemy, thofe of the daughters were Cleopatra and
Arfinoe. This was the Cleopatra who afterwards be¬
came fo famous, and had fo great a fhare in the- civil
wars of Rome. As the tranfaftions of the prefent
reign, however, are fo clofely connefted with the af¬
fairs of Rome, that they cannot be well underftood
without knowing the fituation of the Romans at that
time, we refer for an account of them to the Hi/lory
of Rome.
jiiuc — With Cleopatra ended the family of Ptolemy Lagus,
gvpt oil its the founder of the ^Grecian empire in Egypt, after it
conquc.fi: by I,ad ^e]d that country in fubjeftion for the fpace of
ofCairw-m 294 years* From this time Egypt became a province
of the Roman empire, and continued fubjeft to the
emperors of Rome or Conftantinople. In the year
642, it wTas conquered bv the Arabs under Atnru Lbn
al As, one of the generals of the caliph Omar. In the
vear 889, an independent government was fet up in
65
the Ra¬
ni aas.
5S.
State ot E-
this kingdom by Ahmed Ebn Tolun, who reoelied a-
gainft Al Mokhadi caliph of Bagdad. It continued
to be governed by him and his fucceltors for 27 _y^ars»
when it was again reduced by Al MoClafi caliph of
Bagdad. In about 30 years after, we find it again an
independent ftate, being joined with Syria under Ma¬
homet Ebn Taj, who had been appointed governor of
thefe provinces. This government, however, was alio
but fliort-lived ; for in the year 968 it was conquered
by Jawhar, one of the generals of Moez Ledmillah,
the Fatemite caliph of CairwaA in Barbary. See Bar¬
bary, N° 34.
No fooner was Moez informed of the fuccefs of his Moez
general, than he prepared with all expedition to go andj^po.
take poffeffion of his new conqueft. According y e ^-s nev/
ordered all the vaft quantities of gold which he and his j-^gdom.
predeceffors bad amaffed, to be caft into ingots of the
fize and figure of the millftones ufed in band mills, and
conveyed on camels backs into Egypt.. I o ftiowr that
he was fully determined to abandon his dominions .111
Barbary, and to make Egypt- the refidence of himleL
and his fucceflors, he caufed the remains of the three
former princes of his race to be removed fiom Cair-
wan in Barbary, and to be depofited in a (lately mofque
erected for that purpofe in the city of Cairo in Egypt*
This was a moft effeftual method to induce his fuccei-
fors to refide in Egypt alfo, as it was become an.efta-
blithed cuftom and duty among thofe princes frequent¬
ly to pay their refpeCtful vifits to the tombs of tiieir
^ To'eftablifti himfelf the more effectually in his new Will not
dominions, Moez fupprefted the ufual prayers made irj r^s to be
the mofques for the caliphs of Bagdad, and fubftituted for tjlC
his own name in their (lead. Ibis was complied with,caliph of
not only in Egypt and Syria, but even throughout all Bagdad.
Arabia", the city of Mecca alone excepted. The cpn-
fequence was, a fchifm in the Mahommedan faith,
which continued upwards of 2G0 years, and. was at¬
tended with continual anathemas, and fometimes de-
ftructive wars,between the caliphs of Bagdad.and of
Egypt. Having fully eftabliibed himfelf in his king¬
dom, he died in the 45th year of. his age, three years
after he had left his dominions in Barbary and w as
fucceeded by his fon Abu Al Manfur Earar, furnamed
Aziz Billah. /8
The new caliph fuccecded to the throne at the age UjGccds-
of 215 and committed the management of affairs en-^.W^
tirely to the care of Jawhar, his father’s long-expe- gyr
rienced general and prime minifter. In 9.78, he fent
this famous warrior to drive out Al Aftekin, the emir
of Damafcus. The Egyptian general accordingly
formed the fiege of that place ; but at the end of two
months, was obliged to raife it, on the approach of an
army of Karmatians under the command of Al Hakem.
As Jawhar was not ftrong enough to venture an en¬
gagement with thefe Rarmatians, it was impoffible foC
him to hinder them from effecting a junction wit.1! the-
forces of Al Aftekin. He therefore retreated, or. ra¬
ther fled, towards Egypt with the utmoft expedition ;
but being overtaken by the two contederate armies, he
was foon reduced to the laft extremity. He was, how-
evef, permitted to reftime his march, on condition that
he paffed under Al Aftekin’s fword and Al Hakem s
lance •, and to this difgraceful condition Jawhar found
himfelf obliged to (ubmit. On his arrival in Egypt,
4 G 2 he
Egypt.
dp
Aleppo be-
fieged with¬
out fuccefs.
7°
Strange
madnefv of
the cahph
Hakem.
E G Y [604
he immediately advifed A1 Aziz to undertake an expe¬
dition in perfon into the eaft, againft the combined ar¬
my of Turks, Karmatians, and Damafcenes, under the
command of A1 Aftekin and A1 Hakem. The caliph
followed his advice ; and advancing againit his enemies,
overthrew them with great daughter. A1 Aftekin
himfelf efcaped out of the battle ; but was afterwards
taken and. brought to A1 Aziz, who made him his
chamberlain, and treated him with great kindnefs.
Jawhar, in the mean time, was difgraced on account of
his bad fuccefs : and in his difgrace he continued till
his death, which happened in the year of our Lord,
990, and of the Hegira 381.
This year A1 Aziz having received advice of the
death of Saado’dawla prince of Aleppo, fent a formi¬
dable army under the command of a general named
Manjubekin, to reduce that place. Lulu, who had
been appointed guardian to Saado’dawla’s fon, finding
himfelf prefl'ed by the Egyptians, who carried on the
fiege with great vigour, demanded affiftance from the
Greek emperor. Accordingly, he ordered a body of
troops to advance to Lulu’s relief. Manjubekin, being
informed of their approach, immediately raifed the
fiege, and advanced to give them battle. An obfti-
nate engagement enfued, in which the Greeks were
at lalt overthrown with great (laughter^ After this
victory, Manjubekin puftied on the fiege of Aleppo
very brilkly ; but finding the place capable of defend¬
ing itfelf much longer than he at firft imagined, and
his provifions beginning to fail, he raifed the fiege.
The caliph upon this fent him a very threatening letter,
and commanded him to return before Aleppo. He did
fo ; and continued the fiege for 13 months ; during all
which time it w^as defended by Lulu with incredible
bravery. At laft, the Egyptians hearing that a numer¬
ous army of Greeks vras on their wray to relieve the
city, they raifed the fiege, and fled wdth the utmofl:
precipitation. The Greeks then took and plundered
fome of the cities which A1 Aziz poffeffed in Syria j
and Manjubekin made the belt of his wfay to Damafcus,
where he fet up for himfelf. A1 Aziz being inform¬
ed of this revolt, marched in perfon againit him with
a conliderable army j but being taken ill by the way,
he expired, in the 2lit year of his reign and 42d of
his age.
A1 Aziz was fucceeded by his fon Abu A1 Manfur,
furnamed A1 Hakem j who, being only 11 years of age,
was put under the tuition of a eunuch of approved
integrity.
This reign is remarkable for nothing fo much as the
madnefs with which the caliph was feized in the latter
part of it. This manifefted itfelf firlt by his iffuing
many prepofterous edifts j but at length grew to fuch
a height, that he fancied himfelf a god, and found no
fewer than 16,000 perfons who owned him as fuch.
Thefe were moftly the Dararians, a new feed: fprung
up about this time, who were fo called from their chief,
Mohammed Ebn Ifhmael, furnamed Darari. He is
fuppofed to have infpired the mad caliph with this im¬
pious notion ; and, as Darari fet up for a fecond Mo-
fes, he did not fcruple to affert that A1 Hakem w as the
great Creator of the univerfe. For this reafon, a zea¬
lous Turk ftabbed him in the caliph’s chariot. His
death was followed by a three days uproar in the city
-ef Cairo) during which, Darari’s houfe was pulled
]
E G Y
down, and many of his followers maflacred. The fe&, Egypt,
however, did tot expire with its author. He left be- —y—^
hind him a difciple named Hamza, wdro, being encou¬
raged by the mad caliph, fpread it far and wide through
his dominions. This was quickly followed by an abro¬
gation of all the Mahommedan fails, feftivals, and pil¬
grimages, the grand one to Mecca in particular j fo
that the zealous Mahometans wrere now greatly alarm¬
ed, as juftly fuppoimg that A1 Hakem deligned en¬
tire <y to lupprefs the worfliip of the true God, and in¬
troduce his own in its place. From this apprehenfion,
however, they w^ere delivered by the death of the ca¬
hph j who was affaflinated, by a contrivance of his own
filler, in the year 10 20.
A1 Hakem was fucceeded by his fon A1 Thaher
who reigned 15 years ; and left the throne to a fon un¬
der feven years of age, named A1 Moltanfer Billah. 
In the year 1041, a revolt happened in Syria ; but A1
Moitanfer having fent a powerful army into that coun¬
try, under the command of one slnujhtehin, he not only
reduced the rebels, but conliderably enlarged the E-
gyptian dominions in Syria.
In 1054, a Turk named A1 Baffafiri, having quar-a) Moftan,
relied with the vizir of A1 Kayem caliph of Bagdad, fled ferattempts
to Egypt, and put himfelf under the protedion oftheton-
A1 Moilanfer. The latter, imagining this would be a g’' f! °f
favourable opportunity for enlarging his dominions, and BaS 3 *
perhaps feizing on the city of Bagdad, fupplied Baffa¬
firi with money and troops. By this affiilance, he was
enabled to poffefs himfelf of Arabian Irak, and rava-faliph ef
ged that province to the very gates of Bagdad. On agdad af.
this, A1 Kayem wrote to Togrol Beg, or Tangroli- ^
pix, the lurkifh fultan, who poffefled very extenfive
dominions in the call, to come to his aflillance. The ^
fultan immediately complied with his requell, and foon
arrived at Bagdad with a formidable army and 18 ele¬
phants. Of this Baffafiri gave notice to A1 Moilan¬
fer, and entreated him to exert himfelf further for his
fupport againll fo powerful an enemy. This was ac¬
cordingly done, but nothing worthy of notice happen¬
ed till the year 1058. At this time Baffafiri having
found means to excite Ibrahim the fultan’s brother tb
a revolt, Togrol Beg was obliged to employ all his
force againll him. This gave Baffafiri an opportunity 73
of feizing on the city of Bagdad itfelf j and the unfor-
tunate caliph, according to fome, was taken prifoner,
or, accordingly to others, fled out of the city. Baflafiri,
on his entry, caufed A1 Moltanfer to be immediately
proclaimed caliph in all quarters of the city. A1 Kay-
em’s vizir he caufed to be led on a camel through the
llreets of Bagdad, dreffed in a woollen gown, with a
high red bonnet, and a leathern collar about his neck; a
man lathing him all the way behind. Then being fewed
up in a bull’s hide, with the horns placed over his
head, and hung upon hooks, he was beaten without
ceafing till he died. The imperial palace was plun¬
dered, and the caliph himfelf detained a clofe pri¬
foner.
This fuccefs was but Ihort-lived ; for, in 1059, To- nv t
grol Beg defeated his brother Ibrahim, took him pri- reftoredl^
foner, and Itrangled him with a bow tiring. He then
marched to Bagdad, which Baflafiri thought proper to
abandon at his approach. Here the caliph A1 Kayem
was delivered up by Mahras, the governor of a city
called Haditha, who had the charge of him. The
E G Y
[ 605 ]
E G Y
Egypt caliph was immediately reftored to his digiuty ; which
—-Y 1 Bailaiiri no fooner underftood, than he again advanced
towards the city. Againit him Togrol Beg lent a
part of his army under fome of his generals, while he
himfelf followed with the reft. A battle enfaed m
which the army of Baifaliri was defeated, and he him¬
felf killed. His head was brought to 1 ogrol Beg,
who caufed it to be carried on a pike through the
ftreets of Bagdad. • 1 r
Thus the hopes of A1 Moftanfer were entirely iru-
Egypt.
75 f
Decline o: x uus luc w*    , .
the Egyp- ftrated ; and from this period we may date the decien
tianempire — . • 1 ^ i
7« r
Terrible fa'
mine and
plague.
73
77
Invaded by
the Turks
lion of the Egyptian empire under the caliphs.. They
had made themfelves mafters of almoft all Syria j but
no fooner was Balfafiri’s bad fuccefs known, than the
younger part of the citizens of Aleppo revolted, and
fet up Mahmud Azzo’dawla, who immediately laid
liege to the citadel. A1 Moftanfer fent a powerful ar¬
my againft him, which Azzo’dawla entirely defeated,
and took the general himfelf prifoner •, and foon after
this, he made himfelf mafter both of the city and cita¬
del, with all their dependencies. In his new domi¬
nions he behaved with the greateft cruelty, deftroymg
every thing with fire and fword, and making frequent
incurlions into the neighbouring provinces, -which he
treated in the fame manner.
This difafter was foon followed by others lull more
terrible. In 1066, a famine raged over all Egypt and
Syria, with luch fury, that dogs and cats were iold. or
four or five Egyptian dinars each, and other provihons
in proportion. Multitudes of people died in Cairo for
want of food. Nay, fo great was the Icarcity, that
the vizir had but one fervant left who was able to attend
him to the caliph’s palace, and to whom he gave the
care of his horle when he alighted at the gate. But
at his return, he was furprifed to find that the horle
had been carried off, killed and eaten by the famifhed
people. Of this he complained to the caliph ; who
caul'ed three of them who had carried off the horie to
be hanged. Next day, however, he was ftill more iur-
prifed to hear, that all the ilefh had been picked oft the
bones of the three unhappy criminals, lo that nothing
but the fkeletons were left. And to fuch a degree of
xnifery were the inhabitants, not only m Cairo but
through all Egypt, reduced, that the carcafes of thole
who died were fold for food at a great price, inftead
of being buried. All this time the caliph {bowed the
greateft kindnefs and beneficence towards his unhappy
fobjeels 1 infomuch that of 10,000 hories, mules, and
camels, which he had in his {tables when the famine be¬
gan, he had only three left when it was removed.
The famine was followed by a plague *, and this y
-an invafion of the Turks under Abu Ah A1 Halan
Naferod’dawla, the very general who had been lent a-
gainft the rebel Azzo’dawla and defeated by him.
He began with befieging the caliph in his own palace j
and the unhappy prince, being in no condition to make
refiftance, was obliged to buy himfelf off at the ex¬
pence of every thing valuable that was left m ms ex-
haufted capital and treafury. Ihis, however, did not
hinder thofe .mercilefs plunderers from ravaging a
the Lower Egypt from Cairo to Alexandria, and com¬
mitting the moft horrid cruelties through that whok
trafl.—This happened in the years 1067 and 1068 j
and in 1069 and 1070, there happened two other re¬
volts in Syria : fo that this country was now almoft
entirely loft. „ r 1 •
In 1095 died the caliph A1 Moftanfer, having reign¬
ed 60 years : and was fucceeded by his fon Abul Ea-
fem, furnamed A1 Moitali. The moft remarkaole
tranfaction of this prince’s reign, was his taking the
city of Jeruialem from the Turks in 10985 but this
fuccefs was only of Ihort duration > for it was the lame
year taken by the crufaders. • t*
From this time to the year 1164, the Egyptian hi-
ftory affords little elfe than an account of the mteftine
broils and contefts between the vizirs or prime mini-
fters, who were now become fo powerful, that , they
had in a great meafure ftripped the caliphs of their ci¬
vil power, and left them nothing but a ftiadow of ipi-
ritual dignity. Thefe contefts at laft gave occafion to ?9
a revolution, by which the race of Fatemite caliphs revolu-
was totally extinguiftied. This revolution was accom- t on in the
pliihed in the following manner. One S/iawer, having kingdom,
overcome all his competitors, became vizir to A1 A-
ded, the eleventh caliph of Egypt. He had not been
long in poffeflion of this oftice, when A1 Dargam, an
officer of rank, endeavoured to deprive him of it.
Both parties quickly had recourfe to arms j and a battle
enfued, in which Shawer was defeated, and obliged
to fiy to Nuroddin prince of Syria, by whom he was
graciouily received, and who promiied to reinftate him
in his office of vizir. As an inducement to Nuroddin
to aftift him more powerfully, Shawer told him tha*.
the crufaders had landed in Egypt, and made a con.
fiderable progrefs in the conqueit of it. He promiied
alfo, that, in cafe he was reinftated in his oftice, he
would pay Nuroddin annually the third part of the re¬
venues of Egypt 5 and would, befides, defray the whole
expence of the expedition. .
As Nuroddin bore an implacable hatred to the Chri-
ftians, he readily undertook an expedition againft them,
for which he was to be fo well paid. He therefore
fent an army into Egypt under the command of Shawer
and a general named Afadoddin. I)argam,in the. mean,
time, had cut off fo many generals whom he imagi¬
ned favourable to Shawer’s intereft,. that he thereby
weakened the military force of the kingdom, and in a
great meafure deprived himfelf of the power of refift-
ance. He was therefore eafily overthrown by Aft.a-
doddin, and Shawer reinftated in the office of vizir.
The faithlefs minifter, however, no fooner faw himfelf
firmly eftablifhed in his office, than he refufed .to mlfil
his engagements to Nuroddin by paying the ftipulated
funis. Upon this, Afadoddin feized Peluiiuin and xorne
other cities. Shawer then entered into an alliance with
the crufaders, and Afadoddin was befieged by their com¬
bined forces in Pelufium. Nuroddin, however, having
invaded the Chnftian dominions in Syria, and taken a
ftrong fortrefs called Harem, Shawer and his confede¬
rates thought proper to hearken to fome terms of ac¬
commodation, and Afadoddin was permitted to depart
for Syria.
In the mean time, Nuroddin, having fobdued the
greateft part of Syria and Mefopotamia, refolved to
make Shawer feel the weight of his refentment on
account of his perfidious conduft. He therefore fent
back Afadoddin into Egypt with a fufficient force,
to compel Shawer to fulfil his engagements: but this
E G Y
Efypt- , t}]c vJzir took care to do before the arrival of Afidod-
din ; and thus, for the prefent, avoided the danger.
It was not long, however, before he gave Nuroddin
. 1 occafion to fend this general again It him. That
prince had now driven the crufaders almoit entirely
out of Syria, but was greatly alarmed at their progrefs
m h-gypt 5 and confequently offended at the alliance
which Shawer had concluded with them, and which
he Itill perlifted in obferving. This treaty was alfo
thought to be contrived on purpofe to prevent Shawer
from being able to fulfil his promife to Nuroddin, of
fending him annually a third of the revenues of Eoypt.
Nuroddin therefore again defpatched Afadoddin into
Egypt, m the year 1166, with a fufficient force, and
attended by the famous Salahaddin, or Saladin, his
own nephew. They entered the kingdom without op-
pofition, and totally defeated Shawer and the crufa-
ders._ They next made themfelves mailers of Alex¬
andria ; and, after that, overran all the Upper Egypt.
Saladin was left with a confiderable garrifon in Alexan¬
dria j but Afadoddin was no fooner gone, than the
crufaders laid fiege to that city. This at laft obliged
Aladoddm to return to its relief. The great Ioffes he
lad fuftained in this expedition probably occafioned
his agreeing to a treaty with Shawer, by which he
engaged to retire out of Egypt, upon being paid a
ium of money.
A fadoddm was no {boner gone, than Shawer enter-
e .mto a frefh treaty with the Franks. By this new'
alliance he was to attack Nuroddin in his own domi-
mons, as he was at that time engaged in quelling fome
revolters, wdiich would effedtually prevent his fending
\ny more forces into Egypt. This treaty fo provoked
the Syrian prince, that he refolved to fufpend his other
conquells for fome time, and exert his whole ifrength
m the conqueft of Egypt.
By this time the crufaders had reduced Pelufium,
and made a confiderable progrefs in the kingdom, as
well as in fome other countries, through the divifions
which reigned among the Mahometan princes. In
fuch places as they conquered, they put almoft every
body to the fword, Chriftians as well as Mahometans 5
felling their prifoners for Haves, and giving up the
towns to be plundered by the foldiers. From Pelu¬
fium they, marched to Cairo ; which was then in no
pofture of defence, and in the utmoft confufion, by
reafon of the divifions which reigned in it. Shawer,
therefore, as foon as he heard of their approach, cau-
fed the ancient quarter called Me/r to be fet on fire
and the inhabitants to retire into the other parts. He
alfo prevailed upon the caliph to folicit the affifiance
of Nuroddin ; which the latter was indeed pretty much
inclined of himfelf to grant, as it gave him the faireft
opportunity he could have walked for, both of driving
the crufaders out of Egypt, and of feizing the king¬
dom to himfelf. For this purpofe he had already railed
an army of 60,000 horfe underhis general Afadoddin •
and, on the receipt of A1 Aded’s meffage, gave them
orders to let out immediately. The crufaders were
now' arrived at Cairo ■, and had fo clofely befieged that
place, that neither Shawer nor the caliph knew any
thing of the approach of the Moflem army which was
haliening to their relief. The vizir, therefore, find¬
ing it impoffible to hold out long againft the enemy,
had recouife to his old fubterfuge of treaties and high
4
Egypt
So
Conquefts
of the- cru¬
faders.
[ 606 ] E G Y
promifes. He fent tlie enemy 100,000 dinars, and
promiled them 900,000 more, if they would raife the
fiege ; which they, dreading the approach of Afadod¬
din, very readily accepted.
I he army of Nuroddin now'approached the capital They are
by hally marches, and were everywhere received with repulfed by
the. greateft demonftrations of joy. Afadoddin, on histfiearmy°f
arrival at Cairo, w'as invited by A1 Aded to the royal Nliroddin
palace, where he was entertained in the moff magnifi- DamafrL
cent manner, and received feveral prefents 5 nor wTere
Saladin and the other principal officers lefs magnificent¬
ly treated. Shawer alfo, confcious of his perfidious
condua, was no lefs affiduous in attending punaually
upon him. But having invited the general and Ibme
others to an entertainment, he had formed a fcheme of
haying them feized and murdered. The plot, however
being difcove.red, Shawer himfelf had his head cut off
and Afadoddin w'as made vizir in his ftead. He did
not, however, long enjoy his new dignity ; for he died
fucceeded'in hlf offir ^ being 5e.
lucceeded in his office of vizir by his nephew Sala-comes vizir
i he new vizir was the youngeft of all the grandees
who afpired to that office, but had already given fome
fignal proofs of his valour and conduct. What deter¬
mined the caliph to prefer him to all the reft is not
known 3 but it is certain that fome of them were highly
dupleafed w ith his pi emotion, and even publicly de¬
clared that they wmuld not obey him. In order to gain
thefe to his mtereft, therefore, Saladin found it necef-
iary to diftribute among them part of the vaft treafures
left by his uncle 5 by which means he foon governed
Egypt without controul, as had been cuftomary with
the vizirs for fome time before. Soon after his being
mftahed into the office of vizir, he gave a total defeat
to the negroes who guarded the royal palace, and had
oppofed his eleftion ; by which means, and a ftrong
garnfon he had placed in the caftle of Cairo, his power
became firmly eftabliffied. Though he had not the
leaft. intention of continuing in his allegiance to Nu-
r odd in, he did not think it prudent at firft to declare
himfelf. He fent for his father, however, and the reft
01 his family, who W'ere in Nuroddin’s dominions, in
cider, as he faid, to make them partakers of his gran¬
deur and happinefs. Nuroddin did net think proper
to deny this requeft ; though, being already jealous of
the great power of Saladin, he infilled that his family
fiiould confider him only as one of his generals in E-
gypt-
A good underftanding fubfifted between Nuroddin
and Saladin for fome time, wEich did not a little con¬
tribute to raife the credit of the latter with the Egyp¬
tians, In 1169, Nuroddin fent him orders to omit
the name of A1 Aded, the caliph of Egypt, in the pu¬
blic. prayers, and fubftitute that of the caliph of Bagdad
in its place. Ibis was at any rate a dangerous at¬
tempt j as it might very readily produce a revolt in fa¬
vour of A1 Aded : or if it did not, it gave Saladin an
opportunity of engroffing even that fmall remnant of
power which was left to the caliph. A1 Aded, how'- .
ever, was not fenfible of his difgrace ; for he was on Seize/the
his deathbed, and part recovery, when Nuroddin’s or- effects of
ders were executed. After his death, Saladin feized onthe calipk
all his wealth and valuable effecls 5 which confided of
jewels of prodigious fize, fumptuous furniture, a library
containing
E G Y
[ 607 ]
E G Y
Egypt.
84
Afpires to
the crown.
Subdues A-
rahk Felix
86
Aflumes
the title of
fultan.
containing 100,000 volumes, &c. His family he caufed
to be clofely confined in the moll private and retired
part of the palace ; and either manumitted his flaves,
or kept them for himfelf, or difpofed of them to
others.
Saladin was now arrived at the highell pitch of
wealth, power, and grandeur. He was, howevef, ob¬
liged to behave with great circumfpeCtion with regard
to Nuroddin : who Hill continued to treat him as his
vaffal, and would not fuffer him to difpute the leaf! of
his commands. He relied for advice chidiy on his fa¬
ther Ayub t who was a confummate politician, and
very ambitious of feeing his fon raifed to the throne of
Egypt. He therefore advifed Saladin to continue lled-
falt in his refolutions; and, whilft he amufed Nuroddin
with feigned fubmiffions, to take every method in his
power to fecure himfelf in the poffeffion of fo valuable
a kingdom. Nuroddin himfelf, however, was too great
a mailer in the art of diHimulation to be eafily impofed
on by others 5 and therefore, though he pretended to
be well pleafed with Saladin’s conduct, he was all this
time raifing a powerful army, with which he was fully
determined to invade Egypt the following year. But
while he meditated this expedition, he was feized with
a quinfy at the caftle of Damafcus, which put an end
to his life, in the year 1173-
Saladin, though now freed from the apprehenfions
of fuch a formidable enemy, dared not venture to af-
lume the title of Sovereign, while he faw the fucceffor
of Nuroddin at the head of a very powerful army, and
no lefs delirous than able to difpoffefs him. For this
reafon his firil care was to fecure to himfelf an afylum,
in cafe he Ihould be obliged to leave Egypt altogether.
For this purpofe he chofe the kingdom of Nubia •, but
having defpatched his brother Malek Turanfhah thi¬
ther, at the head of a confiderable army, the latter
was fo much ilruck with the ilerility and defolate ap¬
pearance of the country, that he returned without at¬
tempting any thing. Saladin then fent his brother into
Arabia Felix, in order to fubdue that country, which
had been for fome time held by Abdalnabi an Arabian
prince. Malek entered the country without oppofi-
tion j and having brought Abdalnabi to a general ac¬
tion, entirely defeated him, took him prifoner, and
threw him into irons. He then overran and reduced
under fubjeclion to Saladin great part of the country,
taking no fewer than 80 caftles or fortreffes of confi¬
derable ftrength.
After this good fortune, Saladin, now fore of a con¬
venient place of refuge in cafe of any misfortune, af-
fumed the title of Sultan or fovereign of Egypt ; and
was acknowledged as fuch by the greater part of the
Hates. The zeal of the Egyptians for the Fatemite
caliphs, however, foon produced a rebellion. One Al
Karvz, or Katvzanaddowla, governor of a city in Upper
Egypt, aflembled a great army of blacks, or rather
fwarthy natives ; and marching directly into the lower
country, was there joined by great numbers of other
Egyptians. Againfi them Saladin defpatched his bro¬
ther Malek, who foon defeated and entirely difperfed
them. This, however, did not prevent another infor-
reftion under an impoHor, who pretended to be David
the fon of Al Aded the lafi Fatemite caliph, and had
collected a body of x 00,000 men. But before thefe
had time to do any great damage, they were forprifed
by the fultaft’s forces, and entirely defeated. Above bgypf. (
300 were publicly hanged, and a vafi number perilhed v
in the field, infomuch that it was thought fcarce a
fourth part of the -whole body efcaped.
About this time Saladin gained a confiderable ad¬
vantage over the cmfaders, commanded by William IT.
king of Sicily. That prince had invaded Egypt with
a numerous fleet and army, with which he laid clofe
fiege to Alexandria both by fea and land. Saladin,
horvever, marched to the relief of the city with luch
furprifing expedition, that the crufaders were feized
with a Hidden panic, and fled with the utmofi precipi¬
tation, leaving all their- military engines, flores-, and
baggage behind. 87
In thejear 1175, the inhabitants of Damafcus beg-Saladm
ged of Saladin to accept the fovereignty of that.city
and its dependencies} being jealous of the mmifier,^"^
who had the tuition of the reigning prince, and wjio
governed all with an abfolute livay. Ihe application
was no fooner made, than the fultan fet out with the
utmofl celerity t<v Damafcus, at the head of a chofen
detachment of 700 horfe. Having fettled his aftairs in
that city, he appointed his brother Saif Al lilara go¬
vernor of it ; and fet out for Hems, to which he imme¬
diately laid fiege. Having made himfelf mafler of this
place, he then proceeded to Hamah. 'Ihe city very
foon furrendered, but the citadel held out for fome time.
Saladin pretended that he accepted the fovereignty or"
Damafcus and the other places he had conquered, only
as deputy to Al Malek Al Saleh, the fucceifor of Nu¬
roddin, and who was then under age ; and that he was
defirous of fending Azzoddin, who commanded in the
citadel, with a letter to Aleppo, where the young prince
refided. This fo pleafed Azzoddin, that he took the
oath of fidelity to Saladin, and immediately fet out
with the fultan’s letter. He had not, however, been
long at Aleppo before he vTas by the minifter’s orders
throwm into prifon \ upon which his brother, who had
been appointed governor of the citadel Hamah in his
abfence, delivered it up to Saladin without further ce¬
remony. The fultan then marched to Aleppo, with
a delign to reduce it *, but, being vigoroufly repulfed
in feveral attacks, he was at lafi obliged to abandon the
enterprife. At the fame time, Kamfchlegin, Al Ma-
lek’s minifier or vizir, hired the chief of the Batanifts,
or Aflaflins *, to murder him. Several attempts v7ere * See Atfaf-
made in confequence of this application j but all oty^*-
them, happily for Saladin, mifearried.
After raifing the fiege of Aleppo, Saladin returned
to Hems, which place the crufaders had invefied. On
his approach, however, they thought proper to retire j
after which, the foltan made himfelf mafler of the
flrong caflle belonging to that place, which before
he had not been able to reduce. This was foon fol-
lowTed by the reduftion of Baalbec : and thefe rapid
conquefis fo alarmed the miniflers of Al Malek, that,
entering into a combination with fome of the neigh¬
bouring princes, they raifed a formidable army, with 8g
which they defigned to crufti the fultan at once. Sa-Defeats his
ladin, fearing the event of a war, offered to cede Hems enemies,
and Hamah to Al Malek, and govern Damafcus only
as his lieutenant : but thefe terms being rejected, a
battle enfoed •, in which the allied army was utterly de¬
feated, and the fliattered remains of it fhut up in the
city of Aleppo, This produced a treaty, by which
Saladin
Egypt.
and
90
The Chri.
ftians re¬
ceive a
great defeat
at fea.
91
Saladm’s
rapid con-
^.■uefts.
E G Y [ 608
Saladin was left mafter of all Syria, excepting only the of
city of Aleppo and the territory belonging to it.
In j 176 Saladin returned from the conqueft of Syria,
and made his triumphal entry into Cairo. Here, hav¬
ing refted himfelf and his troops for fome time, he
began to encompafs the city with a wall 29,000 cubits
in length, but which he did not live to finiih. Next
year he led a very numerous army into Paleftine a-
gainft the crufaders. But here his ufual good fortune
failed him. His army was entirely defeated. Forty
thoufand of his men were left dead on the field j and
the reft lied with fo much precipitation, that, having
no towns in the neighbourhood where they could fhel-
ter themfelves, they traverfed the vaft defert between
Paleftine and Egypt, and fcarce Hopped till they
reached the capital itfelf. The greateft part of the
army by this means perilhed and as no water was to
be had in the defert above mentioned, almoft all the
beafts died of thirft before the fugitives arrived on the
confines of Egypt. Saladin himfelf feemed to have
been greatly intimidated j for in a letter to his brother
A1 Malek, he told him, that “ he was more than once
in the moft imminent danger; and that God, as he ap¬
prehended, had delivered him from thence, in order to
referve him for the execution of fome grand and im¬
portant defign.”
In the year 1182, the fultan fet out on an expedi¬
tion to Syria with a formidable army, amidft the ac¬
clamations and good willies of the people. He was,
however, repulfed with lofs both before Aleppo and
A1 Mawfel, after having fpent much time and labour
in befieging thefe two important places.
In the mean time, a moft powerful fleet of Euro¬
pean {hips appeared on the Red fea, which threatened
the cities of Mecca and Medina with the utmoft dan¬
ger. The news of this armament no fooner reach¬
ed Cairo, than Abu Beer, Saladin’s brother, who had
been left viceroy in the fultan’s abfence, caufed an¬
other to be fitted out with all fpeed under the com¬
mand of Lulu, a brave and experienced officer, who
quickly came up with them, and a dreadful engage¬
ment enfued. The Chriftians were defeated after
an obftinate refiftance, and all the prifoners butchered
in cold blood. This proved fuch a terrible blow to
the Europeans, that they never more ventured on a
like attempt.
In 1183, Saladin continued to extend his conquefts.
The city of Amida in Mefopotamia furrendered to him
in eight days 5 after which, being provoked by fome
violences committed by the prince of Aleppo, he re-
folved at all events to make himfelf mafter of that
place. He was now attended with better fuccefs than
formerly $ for as his army was very numerous, and he
puflied on the fiege with the utmoft vigour, Ama-
doddin the prince Capitulated, upon condition of being
allowed to poffefs certain cities in Mefopotamia which
had formerly belonged to him, and being ready to at¬
tend the fultan on whatever expedition he pleafed. Af¬
ter the conqueft of Aleppo, Saladin took three other
cities, and then marched againft his old enemies the
crufaderS. Having fent out a party to reconnoitre the
enemy, they fell in with a confiderable detachment of
Chriftians *, whom they eafily defeated, taking about
100 prifoners, with the lofs of only a Angle man on
their fide. The fultan, animated by this firft inftance
3
] E
fuccefs, drew up his
advanced againft the
Egypt
G Y
forces in order of battle,
crufaders, who had affem-
bled their whole army at Sepphoris in Galilee. On
viewing the fultan’s troops, however, and perceiving
them to be greatly fuperior in ftrength to what they
had at firft apprehended, they thought proper to de¬
cline an engagement, nor could Saladin with all his
{kill force them to it. But though it was found im-
poflible to bring the crufaders to a decifive engage¬
ment, Saladin found means to harafs them great¬
ly, and deftroyed great numbers of their men. He
carried off alfo many prifoners, difmantled three
of their ftrongeft cities, laid wafte their territories,
and concluded the campaign with taking another ftrong
town.
For three years Saladin continued to gain ground onChnftiar.s
the crufaders, yet without any decifive advantage j but totally de--
in xi 87, the fortune of wTar was remarkably unfavour-teate^’
able to them. The Chriftians now' found themfelves
obliged to venture a battle, by reafon of the cruel
ravages committed in their territories by Saladin, and
by reafon of the encroachments he daily made on
them. Both armies therefore being refolved to exert
their utmoft efforts, a moft fierce and bloody battle
enfued. Night prevented vidlory from declaring on
either fide, and the fight was renewed with equal ob«
ftinacy next day. The viftory was ftill left undecided j
but the third day the fultan’s men finding themfelves
furrounded by the enemy on all fides but one, and
there alfo hemmed in by the river Jordan, fo that there
was no room to fly, fought like men in defpair, and
at laft gained a moft complete viftory. Vaft numbers
of the Chriftians periihed on the field. A large body
found means to retire in fafety to the top of a neigh¬
bouring hill covered vrith wood •, but being furrounded
by Saladin’s troops, who fet fire to the w’ood, they
were all obliged to furrender at diferetion. Some of
them were butchered by their enemies as foon as they
delivered themfelves into their hands, and others thrown
into irons. Among the latter were the king of Jeru-
falem himfelf, Arnold prince of A1 Shaw'bec and A1
Carac, the mafters of the Templars and Hofpitalers,
with almoft the whole body of the latter. So great
was the confternation of the Chriftians on this occafion,
that one of Saladin’s men is faid to have taken 30 of
them prifoners, and tied them together wfith the cord
of his tent, to prevent them from making their efcape.
The mafters of the Templars and Hofpitalers, with the
knights a61ing under them, w'ere no fooner brought
into Saladin’s prefence, than he ordered them all to be
cut in pieces. He called them Jljfaflins or Batanifts;
and had been wont to pay 50 dinars for the head of
every Templar or Hofpitaler that was brought him.
After the engagement, Saladin feated himfelf in a
magnificent tent, placing the king of Jerufalem on his
right hand, and Arnold prince of A1 Shawbec and A1
Carac on his left. Then he drank to the former, who
was at that time ready to expire with thirft, and at
the fame time offered him a cup of fnow water. This
was thankfully received j and the king immediately
drank to the prince of A1 Carac, who fat~near him.
But here Saladin interrupted him with fome: warmth :
“ I will not (fays he) fuffer this curled rogue to drink j
as that, according to the laudable and generous cuftom
of the Arabs, would fecure to him his life.” Then,
turning
E G Y
t 609
E G Y
.
His Further
fconqueits.
ggypt. turning towards the prince, he reproached him with
—v-—' having undertaken the expedition while in alliance with
himfelf, with having intercepted an Egyptian caravan
m the time of profound peace, and mailacring the
people of which it Was compofed, &c. Notwithhand¬
ing all this, he told him, he would grant him his life,
if he would embrace Mahometanifnn This condition,
however, was refufed 5 and the fultan, with one ftroke
of his fcimitar, cut off the prince’s head. This great¬
ly terrified the king of Jeruialem but Saladin allured
him he had nothing to fear, and that Arnold had
brought on himfelf a violent death by his want of com¬
mon honelty.
The crufaders being thus totally defeated and dif-
perfed, Saladin next laid fiege to Tiberias, which ca¬
pitulated in a Ihort time. From thence he marched
towards Acca or Ptolemais, which likewife furrendeied
after a lliort fiege. Here he found Mahometan
prifoners in chains, whom he immediately releafed.
As the inhabitants enjoyed at prefent a very extenfive
trade, the place being full of merchants, he found there
not only vaft fums of money, but likewife a great va¬
riety of wares exceedingly valuable, all which he feized
and applied to his own ufe. About the fame time
his brother A1 Make attacked and took a very ftrong
fortrefs in the neighbourhood ^ after which the fultan
divided his army into three bodies, that he might with
the greater facility overrun the territories of the
Chriftians. Thus, in a very Ihort time, he made him¬
felf mailer of Neapolis, Cwfarea, Sepphoris, and other
cities in the neighbourhood of Ptolemais, where his
foldiers found only women and children, the men hav¬
ing been all killed or taken prifoners. His next
conqueft was Joppa, which was taken by ftotm after a
vigorous refiftance. Every thing being then fettled,
and a diftribution made of the fpoils and captives, Sa¬
ladin marched in perfon again!! 1 ebrien, a llrong for¬
trefs in the neighbourhood of Sidon ; which was taken
by affault, after it had fuftained a fiege of fix days.
No fooner was he mailer of this place, than he ordered
the fortrefs to be razed, and the gartrifon put to the
fword. From Tebrien the vidtoiious fultan proceeded
to Sidon itfelf which, being deferted by its prince,
furrendered almofi oh the firft fummons. Berytus
was. next invelted, and furrendered in feven days. A-
mong the prifoners Saladin found in this place the
prince of a territory called Uobei/, who by way of ran-
fom delivered up his dominions to him, and was of
confequence releafed. About the fame time, a Chri-
fiian {hip, in which was a nobleman of great courage
and experience in war, arrived at the harbour of Pto¬
lemais, not knowing that it was in the hands of Sala¬
din. The governor might eafily have fecured the
Veffel ; but neglecting the opportunity, file efcaped
to Tyre, where the above-mentioned nobleman, toge¬
ther wath the prince of Hobeil, contributed not a little
to retrieve the affairs of the Chriitians, and enable them
to make a Hand for four years after.
Saladin in the mean time went on with his con-
quefts. H iving made himfelf mailer of Afcalon after
a fiege of 14 days, he next inverted Jerufalem. I he
garrilbn was numerous, and made an obilinate defence ',
but S iladin having at laft made a breach in the walls
by Tapping, the befieged delired to capitulate. This
was at firft refufed : upon which the Chriftian ambaf-
VoL. VIL Part IE
E?vnt.
54
Jerufalem
taken.
fador made the following fpeech: “ If that be the cafe,
know, O fultan, that we who are extremely numerous, 1
and have been reltrained from fighting like men in de-
fpair only by the hopes of an honourable capitulation,
will kill all our wives and children, commit all our
wealth and valuable effects to the flames, maffacre 5000
prifoners now in our hands, leave not a lingie Dealt of
burden or animal of any kind belonging to us alive,
and level with the ground the rock you eileem lacred,
together with the temple A1 Akla. Aiter this we will
Tally out upon you in a body } and doubt not but we
lhall either cut to pieces a much greater number of you
than we are, or force you to abandon the liege.” I his
delperate fpeech had fuch an effefl upon Saladin, that
he immediately called a council of war, at which all the
general otficers declared, that it would be moil proper
to allow the Chriitians to depart unmoleiled. T he ful¬
tan therefore allowed them to march out freely and fe-
curely with their wives, children, and effefls •, after
which he received ten dinars from every man capable of
paying that fum, five from every woman, and two from
every young ‘perfon under age. For the poor who were
not able to pay any thing, the reft of the inhabitants
raifed the fum of 30,000 dinars.
Moll of the inhabitants of Jerufalem were efcorted
by a detachment of -Saladin’s troops to Tyre j and foon
after, he advanced with his army againil that place.
As the port was blocked up by a Iquadron of five men
of war, Saladin imagined that he ihould eafily become
mailer of it. But in this he found himfelf miftaken.
For, one morning by break of day, a Chriftian fteet fell
upon his fquadron, and entirely defeated it; nor did a
fingle veffel efcape their purfuit. A confiderable num¬
ber of the Mahometans threw themfelves into the fea
during the engagement; moll of whom were drowned,
though fome few efcaped. About the fame time Sala¬
din himfelf was vigoroully repulfed by land } fo that,
after calling a council of war, it was thought proper
to raife the fiege.
In 1188, Saladin, though his conquefts were not fo
rapid and confiderable as hitherto, continued Hill fupe-
rior to his enemies. He reduced the city of Laodicea
and fome others, together with many ftrong c allies j
but met alfo with feveral repulfes. At laft he took the
road to Antioch ; and having reduced all the fortreffes
that lay in his way, many of which had been deemed
impregnable, Bohemond prince of Antioch was fo much
intimidated, that he defired a truce for feven or eight
months. This Saladin found himfelf obliged to com¬
ply with, on account of the prodigious fatigues his men
had fu ained, and becaufe his auxiliaries now demand¬
ed leave to return home. pr
All thefe heavy Ioffes of the Chriftians, however,Crafader*
proved in fome refpefts an advantage, as they were thus ;11
obliged to lay aftde their animofities, which had ongi-lh 11 ai*
nally proved the ruin of their affairs. Thofe who had
defended Jerufalem, and moll of the other fortreffes
taken by Saladin, having retreated to Tyre, formed
there a very numerous body. This proved the means
of preferving that city, and alfo of re-ellablilhing their
affairs for the prefent. For, having received powerful
fucceurs from Euroue, they were enabled in 1189 to
take the field with 30,000 foot and iooo horfe. Jheir
firft attempt was upon Alexandretta; from wdience
they diflodged a ftrong party of Mahometans, and made
4 H themfelvei
airs.
Egypt.
95
Richard I.
of England
arrives in
■Afia.
E G Y [6
themfelves mailers of the place with very little lofs.
' They next laid fiege to Ptolemais 5 of which Saladin
had no fooner received intelligence, than he marched to
the relief of the place. After feveral fldrmifhes with
various fuccefs, a general engagement enfued, in which
Saladin was defeated wTith the lofs of 10,coo men.
i his enabled the Chriilians to carry on the fiege of
Ptolemais with greater vigour ; which place, however,
they were not able to reduce for the fpace of two
years.
This year the fultan was greatly alarmed by an ac¬
count that the emperor of Germany was advancing to
Conliantinople with an army of 260,000 men, in order
to allill the other crufaders. This prodigious arma¬
ment, however, came to nothing. The multitude was
io reduced with licknefs, famine, and fatigue, that fcarce
1000 of them reached the camp before Ptolemais. The
uege of that city was continued, though with bad fuc¬
cefs on the part of the Chriilians. They wrere repulled
in all their attacks, their engines were burnt with
naphtha, and the belieged always received fupplies of
provilions in fpite of the utmofl efforts of the beliegers 5
at the fame time that a dreadful famine and pellilence
raged in the Chriftian camp, which lemetimes carried
off 200 people a-day.
In 1191, the Chriilians received powerful fuccours
from Europe. Philip II. of France, and Richard I.
of England (from his great courage furnamed Caur de
Lion_) arrived at the camp before Ptolemais. The lat¬
ter was elteemed the bravell and moll enterpriling of
all the generals the crufaders had ; and the fpirits of
his foldiers were greatly elated by the thoughts of a£t-
ing under fuch an experienced commander. Soon af¬
ter his arrival, the Englilh funk a Mahometan Ihip of
vail lize, having on board 650 foldiers, a great quantity
of arms and provilions, going from Eerytus to Ptole¬
mais. Of the foldiers and failors who navigated this
veffel, only a fmgle perfon efcaped •, who being taken
prifoner by the Englilh, was defpatched to the fultan
with the newTs of the difaller. The belieged Hill de¬
fended themfelves with the greatell refolution ; and
the king of England happening to fall lick, the ope¬
rations of the beliegers were confiderably delayed. On
his recovery, however, the attacks were renewed with
Inch fury, that the place was every moment in danger
of being taken by affault. This induced them to fend
a letter to Saladin, informing him, that if they did
not. receive fuccours the very next day, they would be
obliged to fubmit. As this fowm was the fultan’s
principal magazine of arms, he was greatly affe&ed
with the account of their dillrefs, efpecially as he
found it impoffible to relieve them. The inhabitants,
therefore, found themfelves under a neceffity of fur¬
rendering the place. One of the terms of the capitu¬
lation W'as, that the crufaders Ihould receive a very
conliderable fum of money from Saladin, in confe-
quence of their delivering up the Mahometan prifoners
they had in their hands. This article Saladin refufed
to. comply wdth ; and, in confequence of his refufal,
FJchard caufed 3000 of thofe unfortunate men to be
llaughtered at once.
After the redu£lion of Ptolemais, the king of Eng¬
land, now made generaliffimo of the crufaders, took the
road to Afcalon, in order to beliege that place j after
vvnich, he intended to make an attempt upon Jexufaleia
10 ] EG Y
itfelf. Saladm propofed to intercept his paffage, and Egypt,
placed himlelf in the wray with an army of 300,000 ——
* On this occalion was fought one of the preatell 97
fViof- cij r 1 • \ Defeats S
men.
battles of that age. Saladin was totally defeated, wTithplcj-Ik
the lofs of 40,000 men; and Afcalon loon fell into the
hands of the crufaders. Other lieges were afterwards
carried on with fuccefs, and Richard even approached
within fight of Jerufalem, w*hen he found, that by rea-
fon. of the weakened Hate of his army, and the divifions
which prevailed among the officers who commanded it,
he Ihould be under the neceffity of concluding a truce
with the lultan. J.his was accordingly done in the
year 1192; the term was, three years, three months,
three weeks., three days, and three hours; foon after
which the king of England let out on his return to his
own dominions.
In 1193 Saladin died, to the inexpreffible grief of
all true Mahometans, wffio held him in the utmoll ve¬
neration. His dominions in Syria and Palefline were
lharedjOut among his children and relations into many
petty principalities. His fon Othman fucceeded to
the crowm of Egypt : but as none of his fucceffors
poffeffed the enterprifmg genius of Saladin, the hiilory
from that time till the year I 250 affords nothing re- Q
markable. At this time the reigning fultan Malek AlMamlouk*
Salek was dethroned and llain by the Mamelucs or Mam- become
fouhy as they are called, a kind of mercenary foldiersmafters of
who ferved under him. In confequence of this revolu-ESyi),;*
tion, the Mamlouks became mailers of Egypt, and
chofe a fultan from among themfelves.—Thefe Mam¬
louks are thought to have been young Turks or Tar¬
tars, fold to private perfons by the merchants, from
■whom they were bought by the fultan, educated at his
expence,. and employed to defend the maritime places
of the kingdom. The reafon of this inllitution origi¬
nally wTas, that the native Egyptians were become fo
cowardly, treacherous, and effeminate, from a long
courfe of llavery, that they wrere unfit for arms. The
Mamlouks, on the contrary, made moll excellent fol¬
diers ; for having no friends but amongll their otvn corps,
they turned all their thoughts to their own profeffion.
According to M. Volney, they came originally from , 99
Mount Caucafus, and are dillinguilhed by the Haxen^^.11^ Cf
colour of their hair. Here they wrere found by the
crufaders, and were by them called Mame/ucs, or more
correctly Mamlouks. The expedition of the Tartars in *
in 1 227 proved indiredlly the means of introducing them
into Egypt. Thefe horrible conquerors, having flaugh-
tered and maffacred till they wTere wTeary, brought along
wdth them an immenfe number of Haves of both fexes,
wdth whom they filled all the markets in Alia.. The
1 urks, taking advantage of the opportunity, purchafed'
about 1 2,000 young men, wdiom they bred up in the
profeffion of arms, in which they foon attained to great
perfeftion ; but becoming mutinous, like the Roman
pretorian bands, they turned their arms againll their
mailers, and in 1250 depofed and murdered the caliph,
as has been already related.
The Mamlouks having got poffeffion of the govern¬
ment, and neither underllanding nor putting a value
upon any thing befides the art of war, every fpecies of
learning decayed in Egypt, and a great degree of bar-
barifm was introduced. Neither w^as their empire of
long duration notwithllanding all their martial abilities.
The reafon of this was, that they were originally only
£ G Y [oi
terft. a fmall part of the futon of Egypt’s tonding forces.
As a numerous [landing army was necenary in a coun¬
try where the fundamental maxim of government was,
\ that every native mull be a Have, they were at hill at a
lofs how to acl} being juftly fufpicious of all the reft
of the army* At lait they refolved to buy Chriftian
[laves, and educate them in the fame Way that they
themfelves had formerly been. Lhefe wrere commonly
brought from Circaffia, where the people, though they
profeffed Chriftianity, made no fcruple of felling their
children* When they were completed in their military
education, thefe foldiers were diipofed of through all
the fortreffes erecled in the country to bridle the inha¬
bitants •, and becaufe in their language fuch a fort was
called Borg?) the new militia obtained the name of
Borgites. ' By this expedient the Mamlouks imagined
they wmuld be able to fecure themfelves in the love-
reignty* But in this they wTere mi [taken.. In p roc eft
of time, the old Mamlouks grew proud, infolent, and
Thriven laz7 • and the B°rglteS» taklng advantage °f this*
by the Bor-rofe upon their mailers, deprived them of the govern-
gites. ment, and transferred it to themffelves about the year
1382*
The Borgites, as well as the former, affirmed the
name of Marnlouhs ; and were famous for their valour
and ferocity of conduct. they were aftnoll perpetu¬
ally engaged in wars either foreign or domeltic-j and
„ their dominion lafted till the year 15171 wken they w ere
Egypt con- invaded by Selim the Turkifti fultan. 1 ne Mamkmks
querc-d by defended themfelves with incredible valour ; notwith-
Selim. [landing which, being overpowered by numbers, they
were defeated in every engagement. I he fame year,
their capital, the city of Cairo, was taken, wdth a ter¬
rible [laughter of thofe who defended it. ihe fultan
was forced to fly} and, having collected all his foice
ventured a decilive battle. 1 he moft romantic efforts
of valour, however, were infufficieilt to cope w ith the
innumerable multitude which compofed the I urkiih
army. Moft of his men wrere cut in pieces, and the un¬
happy prince himfelf was at laft obliged to take fhelter
in a marih. He was dragged from his. hiding-place,
where he had Hood up to the [boulders in wrater, and
foon after put to death. With him ended the glory, and
almoft the exiftence, of the Mawdouks, who watre now
everywhere fearched for and cut in pieces. ^
This was the lait great revolution in the Egyptian
affairs : a revolution very little to the advantage of the
natives, wrho may wrell doubt whether their ancient or
modern conquerors have behaved with the greater de¬
gree of barbarity* Selim gave a ipecimen of his go¬
vernment, the very day after his being put in full poi-
feflion of it, by the death of Tuman Bey the unfortunate
His Horrid fultan above mentioned* Having ordered a theatre tb
ciueity. be erecled with a throne upon it on the banks of the
Nile, he caufed all the prifoners, upwards of 30,000
in number, to be beheaded in his prefence, and their
bodies thrown into the river*
Notwithftanding this horrid cruelty bf Selim, he did
, ] E G Y
not attempt the total extermination of the race of Marti-, ^ Pr*.,
louks, though this -would have been quite agreeable to
the maxims of Turkifti policy j but in the prefent cale
he feems to have recollected, that if he eltablifhed a
pacha in Egypt wnth the fame powers with which he
invefted thofe of other parts, he would be under ftrong
temptations to revolt by reafon of the diftance from the 103
capital* He therefore propofed a new form of govern-New form
ment, by which the power being diftributed among the^™-^
different members of the Hate, fliould preferve an equi- jm-ed
librium, fo that the dependence of the whole ftiould beselim.
upon himfelf. With this view, he chofe from among
the Mamlouks wTho had efcaped the general maffacre,
a divan, or council of regency* confffting of the pacha
and chiefs of the feven military corps. I he former was
to notify to this council the orders of the Porte, to fend
the tribute to Conilantinople, and provide for the fafety
of government both external and internal •, while, on
the other hand, the members of the council had a right
to rejecl the orders of the pacha, or even of depoling
him, provided they could aflign fufficient reafons. All
civil and political ordinances muft alfo be ratified by
them* Befides this, he formed the wftiole body into a
republic *, for which purpofe he iffued an edift to the 104
following purpofe » “ Though, by the help of the Al-jlhedkl
mighty, wre have conquered the whole kingdom of E-
gypt with our invincible armies; nevertheleft our bene¬
volence is willing to grant to the 24 fangiacs (a) of
Egypt a republican government, with the following
conditions.
“ I. That our fovereignty [hall be acknowledged, by
the republic ; and in token of their obedience, our lieu¬
tenant [hall be received as our reprefentative : but to do
nothing agaihft our wull or the republic , but, on the
contrary, [hall co-operate with it for its -welfare on all
occafions. Or if he [hall attempt to infringe any of its
privileges, the republic is at liberty to fufpend him from
his authority, and to fend to our Sublime Porte a com¬
plaint againft him, &c.
“ II. In time of war, the republic [hall provide
I 2,000 troops at its own expence, to be commanded by
a fangiac or fangiacs*
“ III. The republic [hall raife annually and fend to
Our Sublime Porte the fum of 360,000 allany (b), ac¬
companied by a fangiac, who [hall have a iatisfaClory
receipt, &c.
‘‘ IV. The fame fum to be raifed for the ufe of Me¬
dina, and Kiabe or Mecca.
“ V. No more troops of Janizaries [hall be kept by
the republic in time of peace than j 4,000 j but in
time of war they may be increafed to oppoie our and
the republic’s enemies.
“ VI. The republic [hall fend annually to our. gra¬
nary, out of the produce of the country, one million
of cafiz (c) or meafures of corn, viz. 600,000 of wheat
and 400,000 of barley.
“ VII. The republic, fulfilling thefe articles, [hall
have a free government over all the inhabitants of E-
4 H 2 gypt,
(a) Thefe fangiacs are the governors of provinces. . ...
(b) Each of thefe coins is in value about half-a-crowft Englifh ; and the tribute fince that time has been aug¬
mented to 800,000 aflany, or about 100,oool. fterling. _ . .-
(c) Each cafiz weighs occa, and each occa is equal to two pounds.ten ounces Englnh avoirdupois weight*
Egypt.
105
The Turk
ifh powei
now almolt
entirely
loft.
ic6
Why the
children o:
the Mam-
louks and
Turks all
die in E-
gypt-
E G Y [ 6l
gypt, independent of our lieutenant, but diall execute
the laws of the country with the advice of the mollah
or high pried; under our authority and that of our fuc-
ceffors.
VI11- The republic (hall be in poMon of the
mint as heretofore 5 but with this condition, that it fhall
be under the infpedtion of our lieutenant, that the coin
may not be adulterated.
“ That the republic fhall ele£f a Jheik bellet out
ot the number of beys, to be confirmed by our lieute¬
nant 5 and that the faid fheik bellet (hall be our repre-
fentative, and (hall be efteemed by all our lieutenants,
and all our officers both of high and low rank, as the
head of the republic ; and if our lieutenant is guilty of
oppreffion, or exceeds the bounds of his authority, the
faid (heik bellet (hall reprelent the grievances of the
republic to our bublime Porte : but in cafe any foreign
enemy or enemies diilurb the peace of the republic, we
and our fucceffors engage to protect it with our utmoft
power until peace is re-eilabliffied, without any coif or
expence to the republic.
“ Given and ligned by our clemency to the republic
of Egypt.”
Thus the power of the Mamlouks ftill continued in
a very confiderable degree, and by degrees increafed
fo much as to threaten a total lofs of dominion to the
Turks. During the laft 50 years, the Porte having
relaxed from its vigilance, fuch a revolution has taken
place, that the Turkiffi power is now almoft reduced
to nothing. But in order to underftand this, we muft
confider the way in which the race of Mamlouks is
continued or multiplied in Egypt. This is not in the
ordinary way, by marriage . on the contrary, M. Vol-
ney allures us, that “ during 350 years in which there
have been Mamlouks in Egypt, not one of them has
left fubfifting iffue ; all their children perilh in the firft
or lecond defeent. Almoft the fame thing holds good
with regard to the Turks 5 and it is obferved, that
they can only fecure the continuance of their families
by marrying women who are natives, wffiich the Mam¬
louks have always difdained. The means by which
they are perpetuated and multiplied are the fame by
which they were firft eltabliffied, viz. by Haves brought
from their original country. From the time of the
Moguls this commerce has been continued on the
banks of the Cuban and Phafis in the fame manner as
it is carried on in Africa, by the wars among the ho-
ftile tribes, and the mifery or avarice of the inhabi¬
tants, who fell their children' to ftrangers. The (laves
thus procured are firft brought to Conftantinople, and
afterwards difperfed through the empire, where they
are purchafed by the wealthy. When the Turks fub-
dued Egypt (fays M. Volney), they ihould undoubted¬
ly have prohibited this dangerous traffic ; their omit¬
ting which feems about to difpofl'efs them of their con-
quell, and which feveral political errors have long been
preparing.
“ For a confiderable time the Porte had negle&ed
the affairs of this province ; and in order to reftrain the
pachas, had fuffered the divan to extend its power till
2 ] E G Y
the chiefs of the janizaries and azabs were left without
Egypt.
Controul. The foldiers themfelves, become citizens by ,
the marriages they had contracted, wrere no longer the
creatures of Conftantinople ; and a change introduced
into their difeipline (till more increafed thefe diibrders.
At firft the feven military corps had one common trea-
fury j and though the fociety was rich, individuals,
not having any thing at their own difpofal, could effect
nothing. I he chiefs, finding their power diminilhed
by this regulation, had intereft enough to get it abo-
liihed, and obtained permiihon to poliefs diltinCt pro¬
perty, lands, and villagesi And as thefe lands and
villages depended on the Mamlouk governors, it was
neceflary to conciliate them, to prevent their opprellions.
From that xnoment the beys acquired an afeendancy
oyer the foldiers, who till then had treated them with
difdain j and this could not but continually increafe
fince their governments procured them confiderable
riches. Thefe they employed in creating themfelves
friends and creatures. They multiplied their (laves ;
and after emancipating them, employed all their intereft
to promote them to various employments, and advance
them in the army. Thefe upftarts, retaining for their
patrons the fame fuperftitious veneration common in the
Eaft, formed faftions implicitly devoted to their plea- 107
fure.” Thus, about the year 1746, Ibrahim, one of Authority
the kiayas (E>) of the janizaries, rendered himfelf in J1/urP-d by
reality mafter of Egypt; having_managed matters foE^
well, that of the 24 beys or fangiacs eight were of his
houfehold. His influence too was augmented by always
leaving vacancies in order to enjoy the emoluments him¬
felf ; while the officers and foldiers of his corps were
attached to his intereft : and his powrer was completed
by gaining over Rodoan, the moft powerful of all the
colonels, to his intereft. Thus the pacha became alto¬
gether unable to oppofe him, and the orders of the ful-
tan were lefs refpefted than thofe of Ibrahim. On his
death in I757> family, i. e. his enfranchifed (laves,
continued to rule in a defpotic manner. Waging war,
however, among each other, Rodoan, and feveral othex
chiefs were killed ; until, in 1766, Ali Bey, who had
been a principal adior in the difturbances, overcame his
enemies, and for feme time rendered himfelf abfolute
mafter of Egypt. ^ g
Of this man there are various accounts. The fol- Hiftory of
lowing is that given by M. Volney. He begins with Ali Bey.
obferving, that the private hiftory of the Mamlouks in
general muft be fubjedl to great uncertainty, by reafon
of their being generally carried off from their parents at
a time of life when they can remember but little or no¬
thing of their parents; and he remarks, that they are
likewife unwilling to communicate the little they may
happen to remember. It is moft commonly fuppofed,
however, that Ali Bey was born among the Abazans,
a people of Mount Caucafus ; from whom, next to the
Circaflians, the (laves moft valued by the Turks, and
other nations who deal in that commodity, are to be ob¬
tained. Having been brought to a public fale at Cairo, He is9
Ali Bey was bought by two Jew brothers named Ifaac oou^ht and
and Youfef, who made a prefent of him to Ibrahime<lucate(J
Kkya.^a^
(d) Thefe were the commanding officers of the janizaries, azabs, &c. who after the firft year laid down their
employments, and became veterans, with a voice in the divan.
Egypt
E G Y [ 61
Kiaya. At this time he is fuppofed to have been about
M or 14 years old, and was employed by his patron m
offices fimilar to thofe of the pages belonging to European
princes. The ufual education was alfo given him j viz.
that of learning to manage a horfe wellj fire a carabine
and piftol •, throw the djerid, a kind of dart ufed m the
diverfions of that country, and which ffiall be afterwards
defcribed. He was alfo taught the exercde of the
fabre, and a little-’reading and writing. In all the
feats of activity juft mentioned, he difcovered inch im-
petuofity, that he obtained the furname of Djendah, or
“ madman and as he grew up, difcovered an muni¬
tion proportionable to the aftivity diiplayed m his
youth. About the age of 18 or 20, his patron gave
him his freedom •, the badge of which among the lurks
is the letting the beard grow, for among that people it
is thought proper only for women and Haves to want a
beard. By his kind patron alfo he was promoted to
the rank of kachef or governor of a diilnd, and at lalt
ele&ed one of the 24 beys. By the death of Ibrahim
in 17C7, he had an opportunity of fatisfymg his ambi¬
tion ; and now engaged in every fcheme for the promo¬
tion or difgrace of the chiefs, and had a principal ffiare
in the ruin of Rodoan Kiaya above mentioned. Rodo-
an’s place was quickly filled by another, who did not
long enjoy it j and in 1762 Ali Bey, then llyled Sheik-
el-Beled, having got Abdelrahman, toe ponetlor at that
time, exiled, procured himfelf tobeelefted in his room.
„e 15 oa_ However, he foon ffiared the fate of the reft, being con-
niflied, but demned to retire to Gaza. I his place, being undei t re
returns, and dominion of a Turkith pacha, was by no means agree-
able ; for which reafon Ali having turned off to another
the Turkiin . ’ . until in
no
He is ba-
yoke.
in
place, kept himfelf concealed for feme time, until m
1766 his friends at Cairo procured his recal. On this
he appeared fuddenly in that city } and in one nig it
killed four of the beys who were inimical to hisdefigns,
baniffied the reft, and affumed the whole power to him-
felf. Still, however, his ambition was not fatisfied ^
and he determined on nothing lefs then to throw off
his dependence on the Porte altogether, and become
fultan of Egypt. With this view he expelled the
pacha, refufed to pay the accuftomed tribute, and in
the year 1768 proceeded to coin money in his owa name.
The Porte being at that time on the eve of a danger¬
ous war with Ruffia, had not leifure to attend to the
proceedings of Ali Bey ; fo that the latter had an op¬
portunity of going forward with his enterprifes very
Ovi* * omes vigoroufly. His firft expedition was againft an Ara-
an Arabian bian prince named Hammam; againft whom he lent
prince. fav0urite Mohammed Bey, under pretence that
the former had concealed a treafure intruhed with him
2 by Ibrahim Kiaya, and that he afforded protetiion to
Prop1 fes to rebels. Having deftroyed this unfortunate prince, he
make Mec-next began to nut in execution a plan propofed to him
ca the em- by a young Venet an merchant, of rendering Jedda,
v’ftVa-' the port of Mecca, an emporium for all the commerce
commerce" of India •, and even imagined he ffiould be able to make
the Europeans abandon the paffage to the Indies by
the Cape of Good Hope. With this view, he fitted
out fome veffels at Suez 5 and manning them with
Mamlouks, commanded the bey Haffan to fail with
them to Jedda, and feze upon it, while a body of
cavalry under Mohammed Bey advanced againft tlie
town. Both thefe commiffions were executed accord¬
ing to his wifti, and Ali became quite intoxicated with
3 ] E G Y
his fuccefs. Nothing but ideas of conqueft now occu- Egypt. >
pied his mind, without conlidering the immenie dii- ~
proportion between his own force and that ot the grand
lignior. Circumftances, it muff be owned, were at
that time very favourable to his fchemes. ihe thei
Daher was in rebellion againft the Porte in Syria 5 and
the pacha of Damafcus had fo exafperated the people
by his extortions, that they were ready for a revolt. ^
Having therefore made the neceffary preparations, Ah h:s expedi-
Bey defpatched in 1770 about 500 Mamlouks to take tic,n into
poffeflion of Gaza, and thus fecure an entrance into }ria*
Paleftine. Ofman, the pacha of Damafcus, however,
no fooner heard of the invafton than he prepared for war
with the utmoft diligence, while the troops of Ah Bey
held themfelves in readinefs to fly on the firft attack.
They were relieved from their embarraffment by Sheik
Daher, who haftened to their aiiiftance, while Ofman
fled without even offering to make the leaft refiftance j
thus leaving the enemy mailers of all Paleftine without
ftriking a ftroke. About the end of February 1771,
the grand army of Ali Bey arrived j which, by the re-
prefentation made of it in Europe, was fuppofed to IT4
conlift of 60,000 men. M. Volney, however, informs Voiney’s
us, that this army was far from containing 60,000 iol- °
diers j though he allows that there might be two-thirds
of that number, who were claffed as follows : 1. Five
thoufand Mamlouks, conftituting the whole effeaive
part of the army. 2. Fifteen hundred Arabs from Bar¬
bary on foot, conftituting the whole infantry ot the
army. Beiides thefe, the fervants of the Mamlouks,
each of whom had two, would conftitute a body ot
10,000 men. A number of other fervants would con¬
ftitute a body of 2000 : and the reft of the number
would be made up by futlers and other ufual attendants,
on armies. It was commanded by Mohammed Bey the
friend of All. “ But (fays our author) as to order and
difeipline, thefe muft not be mentioned. The armies of
the Turks and Mamlouks are nothing but a confufed
multitude of horfemen, without uniforms, on horfes of
all colours and fizes, without either keeping their ranks
or obferving any regular order.” This rabble took the
road to Acre, leaving wherever they paffed fufficient
marks of their rapacity and want of difeipline. At
Acre a jundlion was formed with the troops of Sheik
Daher, confifting of 1500 Safadians (the name of
Sheik Daher’s fubjefts, from Safad, a village of Gali¬
lee, originally under his jurifdiflion). Theie were on
horfeback, and accompanied by 1 200 Motualis cavalry
under the command of Sheik Naftf, and about 1000
Mogrebian infantry. Thus they proceeded towards
Damafcus, while Ofman prepared to oppofe them by
another army equally numerous and ill regulated.: and
M. Volney gives the following defeription of their ope-
rations . ** The reader muft not here figure to himielf"[ heir ab-
a number of complicated and artificial movements : fuchfurd ure¬
as thofe which, within the laft century, have reduced ^od o
war with us to a fcience of fyftemand calculation. The^J
Aiiatics are unacquainted with the firft elements of this
conduft. Their armies are mere mobs, their marches
ravages, their campaigns inroads, and their battles
bloody frays. The ftrongeft or the moft adventurous
party goes in queft of the other, which frequently flies
without making any refiftance. If they ftand their
ground, they engage pell-mell, difeharge their carabines,
break their fpears, and hack each other with their fabres;
for
on
■Egypt.
E G Y [614
_ f.ur tiley liave fc]dom any cannon, and when they have
they are but of little fervic*. A panic frequently dif-
mes itlelf without caute j one party dies, the other
Ihouts victory j the vanquilhed fubmitto the will of the
conqueror, and the campaign often terminates without
a battle.
. “ Such, jn a great meafure, were the military opera-
tions in Syna m the year 1771. The combined army
of Ah Ley and Sheik Daher marched to Damafcus.
Ihe pachas watted for them j they approached, and, on
the 6th of June, a decilive action took place : the Mam-
louks and Safadians nifhed on the Turks with fuch fury
that, terrified at their courage, they immediately took
to t ig it, and tne pachas were not the lalt in endeavour¬
ing to make their eicape. 1 he allies became matters of
the country, and took pofleflion of the city without op*
petition, there being neither walls nor foldiers to defend
it. 1 he cattle alone refitted. Its ruined fortifications
iad not a fmgle cannon, much lefs gunners ; but it was
iurrounded by a muddy ditch, and behind the ruins
P°^eci a ^ew niuiketeers : and thefe alone were
mfhcient to check this army of cavalry. As the be-
fieged, however, were already conquered by their fears
they capitulated the third day, and the place was to be
iuirendered next morning, when, at day-break, a moft
extraordinary revolution took place.
This was no lefs than the defedtion of Mohammed
n6
I)efe<£tion      
sencraf6^ S whom Ofman had gained over in a con*
ieience during the night. At the moment, therefore,
that the fignal of Arrender w^as expedled, this treache¬
rous general founded a retreat, and turned towards E-
gypt with all his cavalry, flying with as great precipi¬
tation as if he had been purfued by a fuperior army.
Mohammed continued his march with fuch celerity,
that the report of his arrival in Egypt reached Cairo
only fix hours before him. Thus Ali Bey found him-
felf at once deprived of all his expeditions of con-
quefl: $ and what was worfe, found a traitor whom he
durft not punifli at the head of his forces. A hidden
reverfe of fortune now took place. Several veflels laden
with corn for Sheik Daher were taken., by a Ruffian
privateer; and Mohammed Bey, whom lie defigned to
ba^e put to death, not only made his efcape, but was fo
well attended that he could not be attacked. His fol¬
lowers continuing daily to increafe in number, Moham¬
med foon became fufficiently flrong to march towards
Cairo 5 and, in the month of April 1772, having de-
tJy feated the troops of Ali in a rencounter, entered the
He is driven city fword in hand, while the latter had fcarce time to
«ut of make his efcape with 800 Mamlouks* With diffieultv
Cairo, and was enabled to get to Syria by the affiftance of
Sneik Daher, whom he immediately joined with the
troops he had with him. The Turks under Ofman
wxre at that time befieging Sidon, but railed the liege
on the approach of the allied army, confiding of about
Jjefeats the 7000 cavalry.. Though the Turkifh army was at leaf!;
rVrr pvf!nd tlmes Tiumber, the allies did not he fit ate to
attack them, and gained a complete viclory. Their af¬
fairs now began to wear a more favourable afpect 5 but
the military operations were retarded by the fiege of
Yafa, a place which had revolted and wEich, though
defended only by a garden wall, without any ditch, held
out for eight months. In the beginning of 1773 it
capitulated, and Ali Bey began to think of returning
to Cairo. For this purpoie Sheik Daher had promifed
4
with diffi¬
culty gets
into S^ria.
118
retrieves
his affairs.
J E G Y
to furmfli him with fuccours; and the Ruffians, with Egypt.
whom he had now contra&ed an alliance, made him a '—"v 
piomife of the like kind. Ali, however, ruined every
thing by his own impatience. Deceived by an aftro- He is niin.
leger, who pretended that the aufpicious moment when ed by his
ie was highly favoured by the ftars was juft arrived, heown impa*
w-ould. needs let out without waiting for the arrival 0f demc.
his allies. He was alfo farther deceived by a ftratagem
o. Mohammed, who had by force extorted from the
inends of Ali Bey letters preffing his return to Cairo,
w ere the people were weary of his ungrateful Have,
and wanted only his prefence hi order to expel him.
Confiding in thefe promifes, Ali Bey imprudently fef
out with his Mamlouks and 1500 Safadians given'him
by Daher ; but had no fooner entered the defert which
leparates Gaza from Egypt, than he was attacked by
a body of 1000 chofen Mamlouks who were lying in
wait for his arrival. They were commanded by a young
bey, named Alourad; who being enamoured of the
wife of Ali Bey, had obtained a promife of her from
Mohammed, in cafe he could bring him her huflband’s
head. As foon as Mourad perceived the duft by which
the approach of Ali Bey’s armed was announced, he
ruffied upon him, attacked and took prifoner Ali Bey
himfelf, after wounding him in the forehead with a fa-
bre. Being conduced to Mohammed Bey, the latter
pretended to treat him with extraordinary refpe<ft, and
ordered a magnificent tent to be ere&ed for him ; but
in three days he was found dead of liis wrounds, as was
given out ; though fome affirm, perhaps with equal
reafon, that he was poifoned.
After the death of Ali Bey, Mohammed Bey took Is fucceeded
upon him the fupreme dignity 5 but this change ofbyMoham-
mafters proved of very little fervice to the Egyptians. med Bey.
At firft he pretended to be only the defender of the
rights of the fultan, remitted the ufual tribute to Con-
ftantinople, and took the cuftomary oath of unlimited
obedience ; after which he folicited permiffion to make
war upon Sheik Daher, the ally of Ali Bey. The
reafon of this requeft was a mere perfonal pique ; and
as foon as it was granted, he made the moft diligent
preparations for war. Having procured an extraordi¬
nary train of artillery, he provided foreign gunners, and
e the command, of them to an Englilhman named
Robinfon. He brought from Suez a cannon 16 feetHiselpedi-
long, which had for a. confiderable time remained ufe-tion againil
lefs $ and at length, in the month of February 1776, Shei'k
be appeared in Syria with an army equal in number to 1-)a^er'
that which he had formerly commanded when in the
fervice of Ali Bey. Daher’s forces, defpairing of be¬
ing able to cope with fuch a formidable armament,
abandoned Gaza, which Mohammed immediately took
pofleffion of, and then marched towards a fortified
town named Yafa. The hiftory of this fiege M. Vol-
ney gives as a fpecimen of the Afiatic manner of con-
duaing operations of that kind. “ Yafa (fays he), of
tne ancient Joppa, is fituated on a part of the coaft, the liege of
tne general level of which is very little akove the fea.Yafa: a
The city is built on an eminence, in the form of a fu.fPecin>en o*
gar loaf, in height about 130 feet perpendicular. The^ttado?
houfes, diftnbuted on the declivity, appear rifing: above befieging
each other, like the fteps of an amphitheatre. On the towns.
Summit is a finall citadel, which commands the town ;
the bottom of the hill is furrounded by a wall without
a rampart, of 12 or 14 feet high, and two or three in
. thicknefs.
E G Y [ 61
thicknefs. The battlements on the top are the only
tokens by which it is diilinguifhed from a common
garden wall. This wall, which has no ditch, is envi¬
roned by gardens, where lemons, oranges, and cnrons,
grow in this light foil to a molt prodigious fize. The
city was defended by five or fix hundred Safadians and
as many inhabitants, who, at the fight of the enemy,
armed themfelves with their fabres and mulkets j they
had likewife a few brafs cannon, 24 pounders, without
carriages j thefe they mounted as well as they could,
on timbers prepared in a hurry ; and iupplymg the
place-of experience by hatred and courage, they replied
to the fummons of the enemy with menaces and cannon
fhot.
“ Mohammed, finding he mult have recourfe to force,
formed his camp before the town ; but was fo little ac¬
quainted with the bufinefs in which he was engaged,
that he advanced within half cannon fhot. . Ihe. bul¬
lets, which ftiowered upon the tents, apprizing him of
his error, he retreated ; and, by making a frefh expe¬
riment, was convinced he was ftill too near. At length
he dilcovered the proper dillance, and let up his tent,
in which the moft extravagant luxury was difplayed .
around it, without any order, were pitched thoie of the
Mamlouks, while the" Barbary Arabs formed huts with
the trunks and branches of the orange and lemon trees,
and the followers of the army arranged themfelves as
they could : a few guards were diffributed here and
there 5 and, without making a flngle entrenchment,
they called themfelves encamped.
“ Batteries were now to be erected } and a fpot of
riling ground wras made choice of to the fouth-eaif-
ward of the town, where, behind fome garden walls,
eight pieces of cannon were pointed, at 200 paces fiom
the town ; and the firing began, notwithftanding the
mufquetry of the enemy, who, from the tops of the ter¬
races, killed feveral of the gunners.
It is evident that a wall only three feet thick* and
without a rampart, muff foon have a large breach in it }
and the queffion wras not how to mount, but hou to
get through it ? The Mamlouks wrere for doing it on
horfeback j but they were made to comprehend that
this wTas impoffible } and they confented, for the fiiit
time, to march on foot. It muff have been a curious
fight to fee them, with their huge breeches of thick
Venetian cloth, embarraffed with their tucked-up
benicheS) their crooked fabres in hand, and piilols
hanging at their fides, advancing and tumbling among
the ruins of the wrall. 1 hey imagined that they had
conquered every difficulty when this obftacle was fur-
mounted ; but the befieged, who formed a better
judgment, waited till they arrived at the empty fpace
between the city and wall *, where they ailailed them
from the terraces and windows of the houfes with Inch
a Ihower of bullets, that the Mamlouks did not fo much
as think of fetting them on fire, but retired under a
perfuafion that the breach was utterly impracticable,
fince it was impoffible to enter it on liorfeback. Morad
Bey brought them ieveral times back to the charge,
but in vain.
“ Six weeks paffed in this manner ; and Mohammed
wTas diftraCteJ with rage, anxiety, and defpair. I he
befieged however, whofe numbers were diminifhed by
the repeated attacks, became wreary of defending alone
^he caufe of Daher. Some perfons began to treat with-
si . E G Y .
the enemy j and it was propofed to abandon the p^ace^ -ifl'P*'- t
on the Egyptians giving hoflages. Conditions wrere
agreed upon, and the treaty might be conlidered as
concluded, when, in the midit of the fecurity occafion-
ed by this belief, fome Mamlouks entered the town 5
numbers of others followed their example, and attempt- 123
ed to plunder. The inhabitants defended themfelves, The town
and the attack recommenced: the whole army then^n™^
rufhed into the town, which fufiered all the horrors tants
of war 5 men, women and children, young and old, crecl.
were all cut to pieces, and Mohammed, equally mean
and barbarous, caufed a pyramid formed of the beads
of thefe unfortunate fuiferers to be raifed as a monu¬
ment of his viClory.”
By this difafter the greateft terror and confternation
were everywhere diffulcd. Sheik Eaher himfelf fled,
and Mohammed foon became mailer of Acre alfo.
Here he behaved with his ufual cruelty, and abandon¬
ed the city to be plundered by his foldiers. Xhe French
merchants claimed an exemption, and it veas procured
with the utmoil difliculty : nor was even this likely to
be of any confequence ; for Mohammed, informed that
the treaiures of Ibrahim kiaya of Haher had been de-
pofited in that place, made an immediate demand of
them, threatening every one ol the merchants with
death if the treafures were not inftantly produced. A^H^
day was appointed for making the fearch 5 but before jyj0jiain_
this came, the tyrant himfelf died of a malignant fever mej
after two days illnefs. His death was no fooner known
than the army made a precipitate retreat, fuch as has
been already mentioned from Damafcus. Sheik Haber
continued his rebellion for fome time, but was at lalt
entirely defeated, and his head fent to Conflantinople
by Haffim Pacha the Turkiffi high-admiral.
' The death of Mohammed was no fooner known in of
Egypt, than Morad Bey haftened to Cairo in order to Egyp1t/frora
difpute the fovereignty with Ibrahim Bey, who had that time
been intrufted with the government on his departure to the ye-*#
from that place for Syria. Preparations for war were17s6*
made on both fides; but at laft, both parties, finding
that the conteft muff be attended with great difficulty^
as well as very uncertain in the event, thought pro¬
per to come to an accommodation, by which it was
agreed that Ibrahim fliould retain the title of Sheik El
Beled, and the power was to be divided between them.
But now the beys and others who had been promoted
by Ali Bey, perceiving their own importance totally
annihilated by this new faCtion, refolved to fhake off
the yoke, and therefore united in a league under the
title of the Houfe of Ali Bey. They conducted their mat¬
ters with fo much filence and dexterity, that both Mo¬
rad and Ibrahim were obliged to abandon Cairo. In
a ffiort time, however, they returned and defeated their
enemies though three times their number ; but not¬
withftanding this fuccefs, it was not in their power
totally to fupprefs the party. This indeed was owing
entirely to their unfkilfulnefs in the art of war, and
their operations for fome time were very trilling. At
laft, a new combination having been formed among
the beys, five of them were fentenced to banifhment
in the "Delta. They pretended to comply with this;
order, but took the road of the Defert of the Pyra¬
mids, through which they were purfued for three days
to no purpofe. At laft they arrived fafe at M.tniahr
a village fituated on- the Nile, 49 leagues above Cairo.
Here
E G Y [ 6t6
Egypt. Here tlie'y took up their refidence, and being mafters
^ of the river, foon reduced Cairo to diftreis by, inter¬
cepting its provifions. Thus a new expedition became
neceflary, and Ibrahim took the command of it upon
himfelb In the month of October 1783 he fet
out nith an army of 30C0 cavalry 5 the two armies
loon came in fight of each other, but Ibrahim thought
proper to terminate the affair by negociation. This
gave fuch offence to Morad, who fufpe&ed fome plot
again!! himfelf, that he left Cairo. A war betwixt
the two rivals wras now daily expected, and the armies
continued for 25 days in fight of each other, only fe-
parated by the river. Negociations took place 5 and the
five exiled beys, finding themfelves abandoned by Mo¬
rad, took to flight, but were purfued and brought
back to Cairo. Peace feemed now to be re-eflabliflied j
but the jealoufy of the two rivals producing new in¬
trigues, Morad was once more obliged to quit Cairo
in 1784* forming his camp, however, direftly at
the gates of the city, he appeared fo terrible to Ibrahim,
that the latter thought proper in his turn to retire to the
defert, where he remained till March 1785. A new
treaty then took place J by tvllieh the rivals agreed to
fhare the power between them, though there was cer¬
tainly very little probability that fuch a treaty would
be long obferved. Since that time we have no accounts
of any remarkable tranfa&ion in Egypt j nor indeed
can we reafonably expect any thing of confequence in
a country where matters are managed, as M. Volney
expreffes himfelf, by a feries of “ cabals, intrigues,
treachery, and murders.”
Of late Egypt has been vifited by feveral travellers,
all of whom have publilhed defcriptions of the country,
its produftiqns, inhabitants, &c. The lateft are M.
Savary, M. Volney, the baron de Tott, and Mr Bruce;
and from the accounts publifhed by thofe gentlemen
the following geographical dtfcription is principally
uS compiled.
Account of This country is ftill divided into two principal parts,
the coun- called the Upper and Lower Egypt. According to M.
Savary, the former is only a long narrow valley begin-
liing at Syene and terminating at Cairo. It is bound¬
ed by two chains of mountains running from north to
fouth, and taking their rife from the laf! cataradl of
the Nile. On reaching the latitude of Cairo they fe-
parate to the right and left ; the one taking the di¬
rection of Mount Colzoum, the other terminating in
Ibme fand banks near Alexandria ; the former being
compofed of high and deep rocks, the latter of fandy
hillocks over a bed of calcareous Hone. Beyond thefe
mountains are defects bounded by the Red fea on the
caft, and on the weft by other parts of Africa ; having
in the middle that long plain which, even where wide!!,
is not more than nine leagues over. Here the Nile is
confined in its courfe betwixt thefe infuperable barriers,
and during the time of its inundation overflows the
country all the way to the foot of the mountains ; and
Mr Bruce obferves that there is a gradual Hope from
the bed of the river to thofe mountains on both Tides.
The baron de Tott fays, that the mountains four leagues
from the Nile, and facing Cairo, “ are only a ridge of
rocks of about 40 or 50 feet high, which divide Egypt
from the plains of Libya ; which ridge accompanies the
courfe of the river, at a greater or leffer diftance, .and
%ype.
try,
] E G Y
feems as if only intended to ferve as a bank to the ge¬
neral innndution.” 1
Lower Egypt, according to M. Savary, compre¬
hends all the country between Cairo, the Mediterra¬
nean, the ifthmus of Suez and Libya. “ This im-
menfe plain (fays he) prefents on the borders of its’
parching fands a ftrip of lands cultivated along the
canals of the river, and in the middle a triangular iiland
to which the Greeks gave the name of Delta ; at the
top of the angle of which the baron de Tott informs
us the rocks of Libya and the coafts of Arabia open
and recede from each other towards the eaft and weft,
parallel to the Mediterranean. This great extent of
country, from the kingdom of Barca to Gaza, is ei¬
ther overflowed by the river, or Capable of being fo ;
which thus fertilizes in a high degree a traft of coun¬
try feemingly devoted to perpetual barrennefs on ac¬
count of the want of rain and the heat of the cli¬
mate.
According to the teftimonies of both Mr Bruce and Coal^ofiE.
M. Volney, the coaft of Egypt is fo extremely low, that gypt exa
it cannot be difcovered at fea till the mariners come tremely
within a few leagues of it. In ancient times the failors
pretended to know when they approached this country,
by a kind of black mud brought up by their founding
line from the bottom of the fea ; but this notion, though
as old as the days of Herodotus, has been difcovered to
be a miftake by Mr Bruce ; wrho found the mud in
queftion to arife wThile the veffel was oppofite to the
deferts of Barca. All along the coaft of Egypt a ftrong
current fets to the eaftw'ard. i2g
In former times Egypt was much celebrated for its of-he fer=
fertility ; and there is great reafon to believe, that were til.ty of aru
the fame pains beftowed upon the cultivation of the c*ent and
ground, and the diftribution of the w'aters of the Nile ™
in a proper manner, the fame fertility would ftill be
found to remain. The caufe of decreafe in the produce
of Egypt We ftiall defcribe in the words of M. Savary.
“ The canals,” fays he, fpeaking of the Delta, “ which
ufed to convey fertility with their waters, are nowT filled.
The earth no longer watered, and continually expofed
to the burning ardour of the fun, is converted into a
barren fand. In thofe places where formerly were feen
rich fields and flourifliing towns, on the Peluliac, the
Tariclic, and the Mendeiian branches, which all ftrike
out from the canal of Damietta, nothing is to be found
at this day but a few miferable hamlets, furrounded by
date trees and by deferts. Thefe once navigable canals
are now no mo*e than a vain refemblance of what they
were : they have no communication with the lake Men-
zall, but what is merely temporary, on the fwelling of
the Nile 5 they are dry the remainder of the year. By
deepening them by removing the mud depolited by the
river fince the Turks have made themfelves fnarters of
Egypt, the country they pafs through would be again
fertilized, and the Delta recover a third of its great-
nefs.”
Concerning this ifland it has been the opinion of a gavary>j
great many, even from very ancient times, that it was ., count of
produced by the mud brought down by the inunda-the forma¬
tions of the Nile : and this opinion we find adoptedvm ‘'J'1 ot ^
the ftrongeft manner by M. Savary. His account 0£Ue‘ta"
the fuppofed rife of the Delta, and indeed of the
greateft part of Egypt, is to the following purpofe.
In
3
E G 'k [ 61
In tbofe early ages where hiftory has not fixed any
epoch, a certain people defcended from the mountains
near the catarafts into the valley overflowed by the
Nile, and which was then to uninhabitable morals
overgrown with reeds and canes. In wdiat manner, or
from°what motive, thefe people were induced to defcend
from their ancient habitations to inch a place, or hdw
they found means to penetrate into a morafs which he
exprefsly tells us was impenetrable, we are not informed,
neither is it to our prefent purpofe to inquire. At
that time, however, the fea bathed the feet of thole
mountains where the pyramids are built, and advanced
far into Libya. It covered alfo part of the ilthmus
of Suez, and every part of what we now call the Delta
formed a great gulf. After many ages the Egyptians,
by what means is unknown, at lealt not fpecified by
our author (though they ought to have been fo, as the
country it feems was then overflowTed not only by the
river but by the oceanJ, formed canals to carry off the
itagnant wTaters of the Nile ; oppoled Itrong dykes to
its ravages j and, tired of dwelling in the caverns of
rocks, built towns and cities upon Ipots elevated either
by nature or art. Already the river was kept within
its bounds, the habitations of men were out of the reach
of its inundations, and experience had taught the peo¬
ple to forefee and announce them. One of the kings
of Egypt undertook to change the courfe of the river.
After running 25 O leagues between the barriers already
mentioned, meeting with an unfurmountable obflacle to
the right, it turned fuddenly to the left j and taking
its courle to the fouthward of Memphis, it fpreads its
waters through the fands of Libya. The prince we
fpeak of cauied a new bed to be dug for it to the call of
Memphis 5 and by means of a large dyke obliged it to
return between the mountains, and difcharge itfelf into
the gulf that bathes the rock on which the caitle of
Cairo is built. The ancient bed of the river was Hill
to be feen in the time of Herodotus, and may even be
traced at this day acrofs the defects, palling to the weft-
ward of the lakes of natrum. The Arabs ftill bellow
upon it the name of Bahr Belatna, “ or fea without wTa-
tee,” and it is now almoft choked up. To the labours
of this monarch Egypt is indebted lor the Delta. A
reflux of the fea was occalioned by the enormous weight
of the waters of the Nile, which precipitated themfelves
into the bottom of the gulf. Thus the lands and
mud carried along with them wrere collected into heaps 5
and thus the Delta, at firft very inconfideruble, rofe
out of the fea, of which it repelled the limits. It wras
a gift of the river, and it has fince been defended from
the attacks of the ocean by railing dykes around it. Five
hundred years before the Trojan war, according to He¬
rodotus, the Delta wjas in its infancy •, eight cubits of
water being then fufticient to overflow it. Strabo tells
us, that boats palled over it from one extremity to the
other ; and that its towns, built upon artificial emi¬
nences, refembled the illands of the Egean fea. At the
time that Herodotus viiited this country, 15 cubits
were neceffary to cover all the Lower Egypt ; but the
Nile then overflowTed the country for the Ipace of two
days journey to the right and left of the iiland. Un¬
der the Roman empire 16 cubits performed the fame
-effedl. When the Arabs came to have the dominion,
17 cubits were requisite ; and at this day 18 are necef-
fery to produce a plentiful crop } but the inundation
Vol. VIE Part II.
7 ] E G Y
flops at Cairo and the neighbouring country, without Egypt,
being extended over the Lower Egypt. Sometimes, ' ' "v
however, the Nile rifes to 22 cubits •, and the caufe of
this phenomenon is the mud for fo many years accu¬
mulated on the illand. Here, in the fpace of 3284
years, we fee the Delta elevated 14 cubits. Our author
wrote in 1777, and informs us that he twice made the
tour of the illand during the time of the inundation.
“ The river (fays hel flowed in full dreams in the great
branches of Rofetta and Damietta, as well as in thofe
which pafs through the interior part of the country ‘y
but it did not overflow the lands, except in the lower
parts, where the dykes were pierced for the purpole of
watering the plantations of rice. We muft not, how»
ever, imagine, as feveral travellers pretend, that this
illand will continue to rife, and that it will become un¬
fruitful. As it owes its increafe to the annual fettling
of the mud conveyed thither by the Nile, when it ceafes
to be overflowed it will no longer increafe in height,
for it is demonftrated that culture is not fufficient to
raife land.
“ It is natural to imagine that the Delta has in-
creafed in length as well as in height j and of this we
may look upon the following fadl to be a remarkable
proof. Under the reign of Pfammiticus, the Mile-
fians, wdth 30 velTels, landed at the mouth of the Bol-
bitine branch of the Nile, now called that of Rofetta,
where they fortified themfelves. There they built a
town called Metelis, the fame as Faoiie, which, in the
Coptic vocabularies, has prelerved the name of Mefjil.
This town, formerly a feaport, is now nine leagues
diftant from the fea, all which fpace the Delta has in-
creafed in length from the time of Pfammiticus to the
prefent. Homer, in his Odyffey, puts the following
words in the mouth of Menelaus. ‘ In the ftormy fea
which walhes Egypt there is an ifland called Pharos.
Its diftance from the Ihore is fuch, that a veffel with
a fair wind may make the paflage in a day.’ From the
way in wdiich he fpeaks of this ifland in other places,
alfo, we may fuppofe that the ifland of Pharos, in his
time, was not lefs than 20 leagues diftant from the E-
gyptian coaft, though now it forms the port of Alex¬
andria j and this fentiment is confirmed by the moil an¬
cient writers.
“ What prodigious changes great rivers occafion on
the furface of the globe ! How they elevate, at their
mouths, iflands which become at length large portions
of the continent! It is thus that the Nile has formed
almoft all the Lower Egypt, and created out of the.
waters the Delta, which is 90 leagues in circumfe¬
rence. It is thus that the Meander, conftantly repel¬
ling the waves of the Mediterranean, and gradually fill¬
ing up the gulf into which it falls, has placed in the
middle of the land the town of Miletus, formerly a ce¬
lebrated harbour. It is thus that the Tigris and the
Euphrates, let loofe from the Armenian hills, and
fweeping with them in their courfe the fands of Me-
fopotamia, are imperceptibly filling up the Perfian
§ulf-” 130
Thefe are the reafons afligned by M. Savary for Mr Bruce’s
thinking that the Delta, as well as the greateft part of reafons for
the Lower Egypt, had been produced by the Nile j ^ con-
but this opinion is violently contefted by other11.31^ °1)I*
travellers, particularly Mr Bruce, who has given a
pretty long differtation upon it, as well as many occa-
4 I fional
E G Y
Egypt fiotal remarks through the courfe o£ his work. He
— y~~—j j)egjns w;th obferving, I. That the country of Egypt
is entirely a valley bounded by rugged mountains j
whence it might feem natural to imagine that the Nile,
overflowing a country of this kind, would be more
ready to wafh away the foil than add to it. 2. It is
obferved by Dr Shaw, and the fame is confirmed by
our author, that there is a gentle Hope from the mid¬
dle of the valley to the foot of the mountains on each
fide ; fo that the middle, in which is the channel of
the Nile, is really higher than any other part of the
valley. Large trenches are cut acrofs the country from
the channel of the river, and at right angles with it, to
the foot of the mountains. 3. As the river fwells, the
canals become filled with wTater, which naturally de-
fcending to the foot of the mountains, runs out at the
farther end, and overflows the adjacent level country.
4. When the water, having attained the lowefl ground,
begins to flagnate, it does not acquire any motion by
reafon of the canal’s being at right angles with the
channel of the Nile, unlefs in the cafe of exceflive rains
in Ethiopia, when the water by its regurgitation again
joins the llream. In this cafe, the motion of the cur¬
rent is communicated to the whole mafs of wraters, and
every thing is fwept away by them into the lea. 5. It
has been the opinion of feveral authors, that there was
a neceffity for meafuring the height of the inundation on
account of the quantity of mud brought down annually
by the waters, by which the landmarks were fo covered,
that the proprietors could not know their own grounds
after the river fubfided. But whatever might be the rea-
fon of this covering of the landmarks in ancient times, it
is certain that the mud left by the Nile could not be fo
in the time of Herodotus, or during any period of
time affigned by that hiftorian 5 for he affigns only
one foot of increafe of foil throughout Egypt in an
hundred years from the mud left by the river 5 the in¬
creafe during one year, therefore, being only the hun¬
dredth part of a foot, could not cover any landmark
whatever. Befides, the Egyptian lands are at this day
parted by huge blocks of granite, which frequently
have gigantic heads at the end of them j and thefe
could not, at the rate mentioned by Herodotus, be
covered in feveral thoufand years. 6. The Nile does not
now bring down any great quantity of mud ; and it is
abfurd to fuppofe that it can at prefent bring down as
much as it did foon after the creation, or the ages imme¬
diately fucceeding the deluge. Throughout Abyffinia,
according to the teftimony of our author, the channel
of every torrent is now worn to the bare rock, and al-
mofl every rivulet runs in a hard flony bed, all the loofe
earth being long ago walked away 5 fo that an annual
and equable increafe of the earth from the fediment of
the waters is impofhble. 7. Our author made a great
number of trials of the tvater of the Nile during the
time of its inundation in different places. At Bai-
boch, when juft coming down from the cultivated
parts of Abyffinia, and before it enters Sennaar, the
lediment is compofed of fat earth and land, and its
quantity is exceedingly fmall. At the junction of the
Nile and Aftaboras the quantity of fediment is very
little augmented ; confiding ftill of the fame materials,
but now moftly fand. At Syene the quantity of fedi¬
ment was almoft nine times greater than before 5 but
was now compofed ajmoft entirely of fand, with a very
E G Y
fmall quantity of black earth. The eonclufion of cur Egypt.
author’s experiments, however, is different from what v '
we fhould have been led to expect from thofe juft men¬
tioned. “ The experiment at Rofetta (fays he) was
not fo often repeated as the others : but the refult was,
that in the ftrength of the inundation the fediment con-
fifted moftly of land 5 and, toivards the end, was much
the greater part earth. I think thefe experiments con-
clufive, as neither the Nile coming frefti from Abyffinia,
nor the Atbara, though joined by the Mareb, likewife
from the fame country, brought any great quantity of
foil from thence.”
8. Our author goes on to obferve, that had the Nile
brought down the quantities of mud which it has been
laid to do, it ought to have been moft charged with it
at Syene j as there it contained the wffiole that was to
be conveyed by it into Egypt. Inftead of this, howr-
ever, the principal part of the fediment at this place
was fand j and this is very naturally accounted for from
the vaft quantities of fand taken up by the winds in the
deferts between Gooz and Syene. Here our traveller
frequently faw vaft pillars of this kind of fand, which
is fb fine and light as to form an impalpable powder,
traverfmg the defert in various directions. Many of
thefe were driven upon the river j and when it became
calm in the evening, fell down into it entirely j thus
affording materials for the many fandy iflands to be met
with in the Nile.
9. Mr Bruce adopts the opinion of thofe who Tup-
pofe that there has been a continual decreafe of water
fince the creation of the world. In this cafe, therefore,
if the land of Egypt had been continually increafing in
height while the water that was to cover it decrealed j
there muff have been frequent famines on account of
the want of a fufficient inundation. But fo far is this
from being the cale, that, according to the teftimony
of feveral Arabian MSS. there had not, when Mr
Bruce was in Egypt, been one fcarce feafon from the
lownefs of the inundation for 34 years j though during
the fame fpace they had three times experienced a famine
by too great an abundance of water, which carried
away the millet.
10. If there had been fuch an increafe of land as He¬
rodotus and others fuppofe, it muff now have been very
perceptible in feme of the moft ancient public monu¬
ments. This, however, is by no means the cafe. The
bale of every obelilk in Upper Egypt is to this day
quite bare and vifible. Near Thebes there are ftill ex¬
tant two coloffal ftatues, plainly defigned for nilome-
ters, and v/hich ought by this time to have been almoft
covered with earth 5 but notwithftanding the length of
time thefe have remained there, they are ftill bare to
the very bafe.
The ftrongeft argument which the advocates for the odniong of
increafe of land of Egypt can make ufe of is, that various au-
the meafures by which the quantity of inundation is t hors con-
determined are fmaller now than in former times 5 and
thefe fmall meafures are faid to have been introduced Nq^in an-
by the Saracens. On this Mr Bruce very juftly ob-cient times,
ferves, that fuch an expedient could not have anfwer-
ed any good purpofe ; as no decreafe of the meafure
could have augmented the quantity of corn produced
by the ground. M. Savary obferves, that, to render
his calculation concerning the growth of land in Egypt
abfolutely exafl, it would be neceffary to determine
[ 618 ]
E G Y [6
the precife length of the Greek, Rowan, and Arabian
cubit; and even to know the different alterations
which that meafure had undergone among thefe people :
But this nicety he thinks needlefs, looking upon the
general fa& to be fully eftablilhed by what he had faid
before. Mr Bruce, however, has treated the fubjeft
with much greater accuracy. He obferves, that from
the fituation of Canopus, the diftance betwixt Egypt
and Cyprus, and the extenlion of the land to the north¬
ward, it appears that no addition of any confequence
has been made to it for 3000 years patf. The only
argument left for the increafe of land therefore mull be
taken from the nilometer. The ufe of this inftrument
was to determine the quantity of inundation, that fo it
might be known whether the crop would be fufficient
to enable the people to pay the taxes exacled of them
by the fovereign or not. The firft ftep was to know
what fpace of ground was overflowed in a given number
of years and this being determined by menfuration, the
next thing was to afcertain the produce of the ground
upon an average. Thus becoming acquainted with the
greatell and leaf! crops produced, together with the
exadt extent of ground overflowed, they were furnifli-
ed with all the neceflary principles for conftrudling a
nilometer } and nothing now remained but to eredt a
pillar in a proper place, and divide it exadlly into cu¬
bits. This was accordingly done ; the pillar was firfl:
divided into cubits, and thefe again were fubdivided
into digits. The firfl: divifion of this kind was un¬
doubtedly that mentioned in Scripture, and called the
cubit of a man ; being the length of the arm from the
middle of the round bone in th6 elbow to the point of
the middle finger 5 a meafure ftill in ufe among all rude
nations. As no ftandard could be found by which this
meafure might be exactly determined, authors have dif¬
fered very much concerning the true length of the cubit
when reduced to our feet and inches. Dr Arbuthnot
reckons two cubits mentioned in Scripture \ one of them
containing one foot nine inches and tVoV °1 an inch ;
the other one foot and T8o~ of a foot ; but Mr Bruce
is of opinion that both of thefe are too large. He
found, by menfuration, the Egyptian cubit to be ex¬
actly one foot five inches and three-fifths of an inch 5
and Herodotus mentions, that in his time the cubit ufed
for determining the increafe of the Nile wTas the Samian
cubit, about 18 of our inches. The latter alfo informs
us, that in the time of Moeris, the minimum of increafe
was 8 cubits, at wdiich time all Egypt below the city
of Memphis w-as overflowed •, but that in his time 16
or at leaft 15 cubits were neceflary to produce the
fame eflfeft. But to this account Mr Bruce objefts,
that Herodotus could have no certain information con¬
cerning the nilometer, becaufe he himfelf fays that the
priefts, who alone had accefs to it, would tell him no¬
thing of the matter. Herodotus alfo informs us, that
in the time of Moeris, great lakes were dug to carry
off the waters of the inundation ; and this fuperfluous
quantity Mr Bruce fuppofes to have been conveyed in¬
to the defert for the ufe of the Arabs, and that by
fuch a vaft drain the rife of the water on the nilometer
would undoubtedly be diminifhcd. But even granting
that there was fuch a difference between the rife of
the water in the time of Moeris and in that of Hero-
dctus, it does not appear that any thing like it has
appeared ever fince. Strabo, who travelled into Egypt
19 ] EG Y
400 years after the time of Herodotus, found that
eight cubits wrere then the minimum, as well as in
the time of Moeris. From fome pafiages in Strabo,
however, it appears that it required a particular exer¬
tion of induflry to caufe this quantity of wTater pro¬
duce a plentiful crop ; but there is not the leait reafon
to fuppofe, that the very fame induflry was not ne-
ceffary in the time of Moeris ; fo that flill there is not
any increafe of land indicated by the nilometer. About
100 years afterwards, when the emperor Adrian vifited
Egypt, wTe are informed from unqueflionable authority,
that 16 cubits were the minimum when the people were
able to pay their tribute ; and in the fourth century,
under the emperor Julian, 15 cubits were the ftandard j
both which accounts correfpond with that of Herodo¬
tus. Laftly, Procopius, who lived in the time of Juf-
tinian, informs us, that 18 cubits were then requifite for
a minimum.
From thefe accounts, fo various and difcordant, it is No inrreaie
obvious that no certain conclufion can be drawn. It lant! ia
is not indeed eafy to determine the reafon of this dif. tl!ele^ages
ference in point of faft. The only conjecture we can ab]y be fup.
offer is, that as it appears that by proper care a fmaller pofed;
quantity of water will anfwer the purpofe of producing
a plentiful crop, fo it is not unreafonable to fuppofe
that at different periods the induftry of the people hag
varied fo much as to occafion the difagreement in que-
ftion. This would undoubtedly depend very much upon
their governor \ and indeed Strabo informs us that it
was by the care of the governor Petronius, that fuch a
fmall quantity of water was made to anfwer the purpofe.
The conclufion drawn by Mr Bruce from the whole of
the accounts above related, is, that from them it is moft
probable that no increafe of land has been indicated by
the nilometer from the time of Moeris to that of Juftx-
nian.
On the conqueft of Egypt by the Saracens, their nor irf
barbarous and ftupid caliph deftroyed the nilometer, more mo-
caufing another to be built in its ftead, and afterwards ^ern t‘mes"
fixed the ftandard of paying tribute confiderably below
what it had ufually been. The Egyptians rvere thus
kept in continual terror, and conftanfly watched the
new nilometer to obferve the gradual increafe or de-
creafe of the water. On this he ordered the new nilo¬
meter to be deftroyed, and another to be conftrucled,
and all accefs to it to be denied to the people. Which
prohibition is ftill continued to Chriftians j though our
author found means to get over this obftacle, and has
given a figure of the inftrument itfelf. That the people
might not, however, be fuppofed to rertrain in total ig¬
norance of their fituation, he commanded a proclamation
to be daily made concerning the height of the water,
but in fuch an unintelligible manner that nobody was
made any wifer \ nor, according to our author, is the
proclamation underftood at this day. From his own ob-
fervations, however, Mr Bruce concludes, that 15 cubits
are now the minimum of inundation, and as this coin¬
cides with the accounts of it in the times of Herodotus
and Adrian, he fappofes with great probability, that
the lame quantity of water has been neceffary to over¬
flow this country from the earlieft accounts to the pre-
fent time.
It now remains only to take notice of what is faid
by M. Savary concerning the former diftance of the
illand of Pharos from the land to which it is now joined.
4 1 2 ’ With
E G Y
Egypt. With regard to his other affertions concerning the city
’ ' of Metelis having been once a fea port, M. Volney proves
M. Sava- that ll.e has Strabo unfairly, and confequently no
ry’s opinion ftrefs is to be laid upon them. The principal, indeed
concerning the only, evidence which therefore remains, is the paffage
Pharos r^ alrcad7. <'luotecl from Homer, viz. that “the illandof
futetThyM. -^aros as far diftant from one of the mouths of the
Volney. Nile as a veffel can fail in one day before the wind.”
“ ilut (fays M. Volney) when Homer Ipeaks of the
diftance of this iiland, he does not mean its dillance from
the Ihore oppofite, as that traveller (M. Savary) has
tranflated him, but from the land of Egypt and the
river Nile. In the fecond place, by a day’s fail we mull
not underftand that indefinite fpace which the yeffels,
or rather the boats, of the ancient Greeks, could pafs
through in a day 5 but an accurate and determined
meafure of 540 ftadia. This meafure is afcertained by
Herodotus, and is the precife difiance between Pharos
and the Nile, allowing, with M. d’Anville, 27,000
toifes to 540 ftadia. It is therefore far from being
proved, that the increafe of the Delta or of the'continent
was fo rapid as has been reprefented *, and, if we were
difpofed to maintain it, we fhould ftill have to explain
how this fiiore, which has not gained half a league from
the days of Alexander, ftiould have gained eleven in the
far fhorter period from the time of Menelaus to that
conqueror. The utmoft extent of the encroachment of
this land upon the fea, however, may be learned from the
words of Herodotus 5 who informs us, that “ the breadth
°f Egypt, along the fea coaft, from the gulf of Plin-
thine to the lake Serbonis near Mount Callus, is 3600
ftadia; and its length from the fea to Heliopolis 1500
lladia.” Allowing therefore the ftadium of Herodotus
to be between 50 and 51 French toiles, the 1500 ftadia
juft mentioned are equal to 76,000 toifes; which, at the
rate of 57,000 to a degree, gives one degree and near 20
minutes and a half. But from the aftronomical obferva-
tions of M. Niebuhr, who travelled for the king of Den¬
mark in 1761, the difference of latitude between Helio¬
polis, now called Alatarea, and the fea, being one degree
29 minutes at Damietta, and one degree 24 minutes at
Rofetta, there is a difference on one fide of three minutes
and a half, or a league and a half encroachment ; and
eight minutes and a half, or three leagues and a half
on the other.”
Thus the difpute concerning the augmentation of the
land of Egypt by the Nile feems to be abiblutely decid¬
ed ; and the encroachments of it on the fea fo trifling,
that we may juftly doubt whether they exift, or whether
we are not entirely to attribute the apparent differences
to thofe which certainly take place betwixt the ancient
and modern menfuration.. M. Volney gives a very par¬
ticular defcription of the face of the country ; but takes
notice of the inconveniences under which travellers la¬
bour in this country, by which it is rendered extremely
difficult to fay any thing certain with regard to the na¬
ture of the toil or mineral produflions. Thefe arife
from the barbarity and fuperftition of the people, who
imagine all the Europeans to be magicians and forcerers,
who come by their magic art to difcover the treafures
which the genii have concealed under the ruins. So
deep-rooted is this opinion, that no perfon dares walk
alone in the fields, nor can he find any one willing to
accompany him ; by which means he is confined to the
banks of the river, and it is only by comparing the ac-
E G Y
counts of various travellers that any fatisfaflory know- Egypt,
ledge can be acquired. *
According to this author, the entrance into Egypt 135,
at Rofetta prefents a molt delightful profpea, by the ^ountof
perpetual verdure of the palm trees on each fide, the the face of
orchards watered by the river, with orange, lemon, and the coun-
other fruit trees, which grow there in valt abundance ;tr>r-
and the fame beautiful appearance is continued all the
way to Cairo. As we proceed farther up the river, he
fays, that nothing can more refemble the appearance of
the country than the marfhes of the Lower Loire, or
the plains of Flanders : inftead, however, of the numer¬
ous trees and country houfes of the latter, we mult
imagine fome thin woods of palms and fcyamores, with
a few villages of mud-walled cottages built on artificial
mounds. All this part of Egypt is very low and flat,
the declivity of the river being fo gentle, that its wa¬
ters do not flow at a greater rate than one league in an
hour. Throughout the country nothing is to be feen
but palm trees, Angle or in clumps, which become more
rare in proportion as you advance ; with wretched vil¬
lages compofed of huts with mud walls, and a bound-
lefs plain, which at different feafons is an ocean of frefti
water, a miry morafs, a verdant field, or a dufty defert ;
and on every fide an extenfive and foggy horizon, where
the eye is wearied and difgufted. At length, towards
the jun&ion of the two branches of the river, the moun¬
tains of Cairo are difcovered on the eaft ; and to the
fouth-wTeft three detached maffes appear, wfffich from
their triangular form are knowm to be the pyramids.
We now enter a valley which turns to the fouthward,
between twro chains of parallel eminences. That to the
eaft, which extends to the Red fea, merits the name of
a mountain from its fteepnefs and height, as well as that
of a defert from its naked and favage appearance. Its
name in the Arabic language is Mokattam, or the hewn
mountain. The weftern is nothing but a ridge of rock
covered with fand, wfffich has been very properly term¬
ed a natural mound or caufeway. In Ihort, that the read¬
er may at once form an idea of this country, let him
imagine on one fide a narrow fea and rocks; on the
other, immenfe plains of fand; and in the middle, a river,
flowing through a valley of 150 leagues in length and
from three to feven wide, which at the diftance of 30
leagues from the fea feparates into two arms ; the
branches of wfffich wander over a foil almoft free from
obftacles, and void of declivity.
from comparing his owm obfervations with thofe of
other travellers, our author concludes, that the bafis of
all Egypt from Afouan (the ancient Syene) to the Me¬
diterranean, is a continued bed of calcareous ftone of
whitifh hue, and fomewhat foft, containing the fame
kind of {hells met with in the adjacent feas, and w'hich
forms the immenfe quarries extending from Saouadi
to Manfalout for the fpace of more than 25 leagues,
according to the teftimony of Father Sicard.
As this country has been more recently vifited by v
men of eminent abilities and profound refearch, who
appear to have examined every object that prefented
itfelf with a philofopher’s eye, w-e beg leave to add to
the teftimonies of the authors already mentioned, the
fubftance of the French general Reynier’s account of
the face of the country. He informs us, that the bar-,
riers by which Egypt is inclofed muft be ftrong, be-
caufe they have been planted by the hand of nature.
It
[ 620 ]
E G Y [62
It is feparated from Afia by deferts of coniiderable ex¬
tent : and fbould an hoftik army attempt to approach
it on that fide, it would have to take its route through
marlhy grounds below its general level, and presenting
to the traveller little elfe than brackifh water. Its
flat Shore towards the Mediterranean, and the mouths
of the Nile gorged up with mounds of fand, prefent to
an enemy very few places which will be found proper
for the debarkation of troops. Immenfe deferts confti-
tute its natural boundaries on the weft, on which ac¬
count it has nothing to dread but the incurfions of the
Arabs from Barbary. A defert alfo Separates Egypt
from the Red fea, which gives no flattering invitations
to an enemy to invade it from that quarter, the two
ports of that fea being deftitute of refources, and Egypt
itfelf being the only country from which a hoftile army
could procure provifions and camels, fufficient to en¬
able it to crofs the defert.
In upper Egypt, a chain of mountains prefent them-
felves to the eye of the traveller on either fide of the
Nile. The valley between thefe mountains, through
which the courfe of the river is direfted, is nearly five
leagues broad, which the periodical inundations^ of the
river completely cover. Ehis valley alone is inhabit¬
ed, and fufceptible of cultivation. Bhe eaftern chain
of mountains, by which the Nile is Separated from the
Red fea, furpaffes that on the weft in refpeft of height,
terminating by precipices towards the valley, affuming
in different places the appearance of an immenfe wall,
broken irregularly by narrow' valleys, which have owed
their origin to the hidden and temporary torrents of
winter, and Serve for paffes over thefe ftupendous
mountains. The w'eftern chain, by which the valley
of the Nile is Separated from that of Ouafis, has m ge¬
neral a gradual and gentle declivity, although it be¬
comes more abrupt towards Siout, and is fteep from the
angle formed by the Nile towards Hennh, till it reaches
Syene, at which place the mountains have a more con-
fiderable height, affording but a narrow paffage to the
river-
'file diftance between thefe two chains of mountains
is increafed as you approach Cairo, the eaftern chain
terminating near the extremity of the Red fea, without
the appearance of any j unci ion writh the Arabian moun¬
tains, which have a fimilar termination. The weftern
chain declines towards Faycum, taking a north-weft
direflion near Grand Cairo, and forming tne Mediter¬
ranean coaft in a direiSfion to the w7eft. Lower. Egypt
lies between thefe tv,ro great chains ot mountains and
the fea, which has moll probably been formed, at leal!
in a great meafare, by the (lime or mud which the
river Nile depofits, as it is interfeaed by its branches,
and a vaft number of canals.
The feven branches by which the Nile anciently
emptied itfelf into the Mediterranean, are at prefent re¬
duced to two, viz. thofe of Damietta and Rofetta.
There are now no veftiges of the other five, except a
canal or two, which are only navigable during a part
of the year. It is not improbable, that when all the
branches of the Nile wTere entire and diftinft, each ot
them contained about the fame quantity of water.
The cutting of canals to effeft the equilibrium of the
wTater, the channels of wdiich were afterwards neglefted,
would diminilh the quantum of water in one branch
and. increafe it in another. The fait water mingling
i ] E G Y
with the frefh, would deftroy the fecundity ot the
ground in fome places, aad thus induce the inhabitants
to fearch for habitations where they might find the
earth more fertile.
It has already been obferved, that the principal part
of Lower Egypt owes its exiftence to the depofitiou of
mud or earth by the Nile, which alfo formed the banks
at the different mouths of that river. The mud of the
Nile would fir ft cover the low ground neareft to its
bed or channel, and the increafe of land from tne de-
pofition of mud would be more gradual in ns piogieis
in diftant parts, from which circumftance would anfe
the formation of lakes. Ihefe in their turn would be
gradually filled up by the laftd growing out of the de-
pofited mud of the river, which of conlequence would
increafe the boundaries of Lower Egypt, by taking
from the fea •, but as it is natural for the fea to refiit
fuch encroachments, it is probable that the ground
formed by the depofited mud of the Nile will no longer
continue to increafe in one direffion without diminiih-
ing in another. The experience of centuries paft has
fully evinced, that the fea has actually taken more
from the extent of Egypt than has been compenfated.
by the mud of the Nile. By the Ample operation of
natural caufes it may be fafely concluded, that if natuie
and art do not co-operate j if the water is permitted to
increafe, and the channels of the different branches aie
allowed to be augmented, the fea will continue to fnatch
new lands from the inhabitants, which appears to be
the inevitable doom of Egypt, while it continues in
the hands of a people wTho are ignorant and unculti¬
vated.
A large proportion of the land formerly watered by
the branches of the Nile, anciently denoted the Pelu-
fiac, Tanitic, and Mendefian branches, is now the bed
of Lake Menzaleh. Lake Bourlos is not far from the
mouth of what was formerly called the Sebennitic
branch, and Lake Maadieh is near the mouth of the
ancient Canopic. Lake Mareotis was at too great a
diftance from the Nile to be filled up with the mud
which it depofits, the waters of which were diverted
from the lake, by a canal wdiich had been cut for the
conveyance of water to the city of Alexandria j and
having no communication with the fea, its w'aters of
confequence were gradually evaporated. It ftill, how¬
ever, contained a moving fand and a brackilh mud,
which receiving the rain in winter, and a imall portion
of the wTaters from the Nile by the canals of Bahireh,
it exhibits the appearance of a marlh during the greater
part of the year. There are alfo a few lakes which
owe their origin to the redundant waters of the Nile,
diffufing themfelves over hollow' places in which they
are confined, and only difappear by the gradual pro-
cefs of evaporation.
In addition to the branches and chief canals already
mentioned, there are numerous canals in Lower Egypt
by which it is interfered. Thefe convey the waters
of the inundation, which dykes in different diftricls
ferve to retain. By thefe waters the more elevated
grounds are fertilized, and other cantons in fucceftion,
after which they are poured into the lakes, or are loft
in the fea. The fwelling of this remarkable river com¬
mences about the fummer folftice, reaching its utmoft
extent in the autumnal equinox and after appearing
for a few days in all its native majefty, it gradually be-
gms.
E G Y [6
, gins^o fubfule. In point of time there is a difference
* - of fifteen days, and fometimes twice that period, with
refpedl to the rife and fall of the Nile j but it may be
affirmed in general, that Lower Egypt cannot be fafe-
iy palled during any more of the year than from the
beginning of February to the end of Auguff. At this
time the great branches alone contain water, on which
paffage boats are always to be met with.
It is obvious from this fuccindt account of the general
face of the country, that no invading army could carry
Oil any military operations in Lower Egypt during more
than leven months in the year. It may perhaps be ad¬
mitted with truth, that the confines of the defert might
be traverfed during the five remaining months; but the
villages in that diredlion are ill qualified to grant thofe
neceffary fupplies to an army which, after crolTmg the
oeferi., muff be in want of every thing. No communi¬
cation could be kept open from the defert with the in¬
terior, from September to December inclufive. At
this period, therefore, an enemy could not carry on
any military operations in the interior but by water.
Nor wTould an army dellined to defend Egypt find it-
ielf free, from very confiderable embaraffment during
the continuance of the inundation j for as a confider¬
able part of its movements would unavoidably be made
on that element, they would be from the nature of
137 ^ things both tedious and difficult.
accom-itofS r -^ruce ^as given us a particular account of the
the cleferts, ^°urces ^rom whence .■were derived the vail quantities
marble p* marble met with in the remains of ancient build-
mountains, ings in this country. Thefe he difcovered during
his journey from Kenne to Coffeir on the Red fea,
before he took his expedition to Abyffinia. He
gives a moll difmal idea of the deferts through which
he palled. What houfes he met with were conifrudled
like thofe M. Volney mentions, of clay, being no more
than fix. feet in diameter, and about ten in height. The
mountains were the moll dreary and barren that can be
imagined ; and the heat of the fun fo great, that two
ificks rubbed together only for half a minute would
take fire and flame. In theie burning regions no living
creature was to be met with, even the poifonous fer-
pents and fcorpions not being able to find fubfillence.
1 he firll animal he faw was a fpecies of ants in a plain
called Hamra from the purple colour of its fand 5 and
it wras remarkable that thefe infedls were of the fame
colour with the fand itlelf. No water was anywhere
to be met with on the furface ; though at a place call-
ed Legeta there were fome draw-wells, the water of
which was more bitter than foot itfelf. At Hamra the
porphyry mountains and quarries begin, the Hone of
which is at firll foft and brittle ; but the quantity is
immenfe, as a whole day was taken up in palling by
them. Thefe porphyry mountains begin in the latitude
of nearly 24 degrees, and continue along the coalt of
the Red fea to about 22° 30', when they are fucceeded
by the marble mountains j thefe again by others of ala-
baller, and thefe lall by bafaltic mountains. From the
marble mountains our author ftlecled twelve kinds, of
different colours, which he brought along with him.
Some of the mountains appeared to be compofed en¬
tirely^ of red and others of green marble, and by their
different colours afforded an extraordinary fpedlacle.
Not far from the porphyry mountains the cold was fo
.great, that his camels died on his return from Abyf-
J
22 ] E G Y
fmia though the thermometer flood no lower than Egvp#.
42 degrees.
Near to Coffeir he difcovered the quarries whence
the ancients obtained thofe immenfe quantities of mar¬
ble with which they conllrudled fo many wonderful
works. The firft place where the marks of their ope¬
rations were very perceptible, was a mountain much
higher than any they had yet paffed, and where the
Hone was fo hard that it did not even yield to the
blows of a hammer. In this quarry he obferved that
lome duels or channels for conveying water termina¬
ted j which, according to him, ffiowrs that wrater was
one of the means by which thefe hard ftenes were cut.
In four days, , during which our author travelled among
thefe. mountains, he fays, that he had “ paffed more
granite, porphyry, marble, andjafper, than would build
Rome, Athens, Corinth, Syracufe, Memphis, Alex¬
andria, and half a dozen fuch cities.” It appeared to
him that the pafiages between the mountains, and
which lie calls defiles, were not natural but artificial
openings 5 where even whole mountains had been cut
out, in order to preferve a gentle flope towards the
river. This defeent our author fuppofes not to be
above one foot in 50 5 fo that the carriages mull have
gone very eafily, and rather required fomething to re¬
tard their velocity than any force to pull them forward.
Concerning the mountains in general, he obferves, that
the porphyry is very beautiful to the eye, and is difco¬
vered by a fine purple fand without any glofs. An
unvariegated marble of a green colour is generally met
with in the fame mountain ; and where the two meet,
the marble becomes foft for a few inches, but the por¬
phyry retains its hardnefs. The granite has a dirty
brown appearance, being covered with fand •, but on
removing this, it appears of a gray colour with black
fpots, with a reddiffi call all over it. The granite
mountains lie nearer to the Red fea, and feem to have
afforded the materials for Pompey’s pillar. The red-
nefs above mentioned feems to go -off on expofure to the
air ; but re-appears on working or polilhing the ftone
farther. The red marble is next to the granite, though
not met with in the fame mountain. There is alfo a
red kind with white veins, and vaft quantities of the
common green ferpentine. Some famples of that beau¬
tiful marble named Ifiabella were likewife obferved 5 one
of them of that yellowifh call called quaver colour, the
other of the blueifh kind named dove colour. The
moft valuable kind is that named verde antico, which is
found next to the Nile in the mountains of ferpentine.
It is covered by a kind of blue flaky ftone, fomewhat
lighter than a flate, more beautiful than moll kinds of
marble, and when polilhed having the appearance of a
volcanic lava. In thefe quarters the verde antico had
been uncovered in patches of about 20 feet fquare.
There wTere fraall pieces of African marble fcattered a-
bout in feveral places, but no rocks or mountains of it 5
fo that our author conjectures it to lie in the heart of
fome other kind. The whole is fituated on a ridge
wdth a defeent to the eaff and well 5 by which means it
might eafily be conveyed either to the Nile, or Red fea,
while the hard gravel and level ground would readily
allow the heavielt carriages to be moved with very lit¬
tle force. r g
Travellers have talked of an emerald mine in thefe of a"fuppo-
deferts ; but from the refearches of Mr Bruce, it does fed emerald
not
E G Y [ 623 ] E G Y
Egypt, not appear to have any exiftence. In the Red iea in-
'   1 deed, in the latitude of 250 3', at a fmall diftance from
the fouth-weltern coaif, there is an ill and called the
Mountain of Emeralds; but none of thefe precious
Hones are to be met with there. Here,, as well as on
the continent, there were found many pieces of a green
pellucid fubftance 5 but veined, and much fofter than
rock cryftal, though fomewhat harder than glafs. . A
few yards up the mountain he found three pits, which
are fuppofed to have been the mines whence the ancients
obtained the emeralds \ but though many pieces of the
green fubftance above mentioned were met with about
thefe pits, no figns of the true emerald could be per¬
ceived. This lubftance, however, he conjeftures to
have been the fmaragdus of the Romans. In the moun¬
tains of Coffeir, as well as in fome places of the deferts
of Nubia, our author found fome rocks exactly refem-
bling petrified wood.
The only metal faid by the ancients to be produced
in Egypt is copper. On the road to Suez are found
great numbers of thofe ftones called Egijf)tianfints and
x^9 r a pebbles, though the bottom is a hard, calcareous, and
curious ap- fonorous Hone. Here alfo M. Volney tells us, that
pearance. the Hones above mentioned, and which refemble petri¬
fied wood, are to be met with. Thefe, he fays, are
in the form of fmall logs cut flanting at the ends, and
might ealily be taken for petrifactions, though he is
I4n convinced that they are real minerals.
Salt lakes. F. Sicard mentions two lakes, from the water of
which is produced annually a great quantity of fait
containing much mineral alkali: and M. Volney in¬
forms us, that the whole foil of this country is impreg¬
nated with fait j fo that, upon digging to fome depth
in the ground, we always meet with brackilh water im¬
pregnated in fome degree with the mineral alkali as
well as wuth common fait. The two lakes mentioned
by Sicard are Htuated in the defert to the weH of the
.Delta 5 and are three or four leagues in length, and
about a quarter of a league in breadth, with a f olid and
Hony bottom. Fcr nine months in the year they are
without water ; but in the wdnter time there oozes out
of the earth a reddifh violet coloured water, which fills
the lakes to the height of five or fix feet. This being
evaporated by the return of the heat, there remains a
bed of fait two feet thick and very hard, which is bro¬
ken in pieces with iron bars} and no lefs than 30,000
quintals are procured every year from thefe lakes. So
great is the propenfity of the Egyptian foil to produce
fait, that even when the gardens are overflowed for the
fake of watering them, the furface of the ground, af¬
ter the evaporation and abforption of the water, ap¬
pears glazed over with fait. The v/ater found in the
wells contains mineral alkali, marine fait, and a little
Vegetable n^re* M. Volney is of opinion, that the fertile mould
mowd of of Egypt, which is of a blackilh colour, differs effen-
Egypt not tially from that of the other parts *, and is derived from
originally t]ie internal parts of Ethiopia along with the wraters of
t-o'mthe Nile. This feems to contradict what he had before
Ethiopia, advanced againfi M. Savary concerning the increafe of
the land of Egypt by means of the wraters of this ri¬
ver : but there is no reafon at all to fuppofe this kind
of earth to be of a foreign origin j it being ahvays the
refult of vegetation and cultivation. Even the molt
barren and fandy fpots in the world, if properly water¬
ed, and fuch vegetables planted in them as wrould grow i ..
there, in time would be covered with this black earth
as well as others : and of this kind of artificial forma¬
tion of foil, travellers give us a remarkable inflance m
the garden of the monks at Mount Sinai, where the
country is naturally as barren as in any place of the
world. “ The monks of Sinai (fays Dr Shaw), in a
long procefs of time, have covered over with dung and
the iweepings of their convent near four acres of na¬
ked rocks} w'hich produce as good cabbage, roots,
falad, and all kinds of pot herbs, as any foil and cli¬
mate whatfoever. They have likewile raifed olive,
plum, almond, apple, and pear trees, not only in great
numbers, but of excellent kinds. The pears particu¬
larly are in fuch eiteem at Cairo, that there is a pre-
fent of them fent every year to the balhaw and perlons
of the firfi quality. Neither are their grapes inferior
in fize and flavour to any whatfoever : it being fully
demonfirated, by what this little garden produces, how
far an indefatigable induflry can prevail over nature ;
and that feveral places are capable of culture and im¬
provement which were intended by nature to be bar¬
ren, and wdrich the lazy and flothful have ahvays fuf-
fered to be fo.” 142
From this general account of the country, we may NaturJ
reafonably conclude, that the natural fertility of ^
gypt is not diminiflied in modern times, provided the
fame pains were taken in the cultivation of it as former¬
ly j but this is not to be expefted from the prefent
degenerate race of inhabitants. “ The Delta (lays
M. Savary) is at prefent in the molt tavouraole Hate
for agriculture. Walked on the call and wefi by two
rivers formed by the divifion of the Nile, each of which
is as large and more deep than the Loire, interledted
by innumerable rivulets j it prefents to the eye an im-
menfe garden, all the different compartments of which
may be eafily watered. During the three months that
the Thebais is under water, the Delta pofleffes fields
covered with rice, barley, vegetables, and winter fruits.
It is alfo the only part of Egypt where the fame field
produces two crops of grain wuthin the year, the one of
rice, the other of barley.”
The only caufe of all this fertility is the Nile, with¬
out w'hich the whole country would loon become an un¬
inhabitable defert, as rain falls very feldom in this part
of the wTorld. It flows with a very gentle fiream through
the flat country, and its waters are very muddy, fo that
they muff have time to fettle, or even require filtration 143
before they can be drunk. For purifying the water, Method of
the Egyptians, according to M. Volney, ufe bitter purifying
almonds, with W'hich they rub the veffel containing
and then the water becomes light and good j but onin£ .
W'hat principle this ingredient a6ls ve cannot pretend
to determine. Unglazed earthen veflels filled w’ith wra-
ter are kept in every apartment j w'hich by a continual
evaporation through their porous fubffance, render the
contained fluid very cool even in the greatefl heats.
The river continues muddy for fix months: and during
the three which immediately precede the inundation,
the flream being reduced to an inconfiderable depth, be¬
comes heated, green, fetid, and full of worms. The
Egyptians in former times paid divine honours to the
Nile, and Hill hold it in great veneration. They believe
its waters to be very nouriflung, and that they are fupe-
rior
E G Y
, -Egypt-
*44.
Of the in¬
undation of
the Nile.. ma
. *45
Nilometer
defcribed.
rior to any in the world; an opinion very excufable in
them, as they have no other, and large draughts of cold
water are among their highert luxuries.
This river, fwelled by the rains which fall in Abyfli-
i, begins to rife in Egypt about the month of May;
but the increafe is inconfiderable till towards the end of
June, when it is proclaimed by a public crier through
the ftreets of Cairo. About this time it has ufually rifen
five or fix cubits; and when it has rifen to 16, great
rejoicings are made, and the people cry out Waffah
Allah, that is, that God has given them abundance. This
commonly takes place about the latter end of July, or
at fartheit before the 20th of Auguil; and the fooner
it takes place, fo much the greater are the hopes of a
good crop. Sometimes, though rarely, the neceffary
increafe does not take place till later. In the year x 705,
it did not fwell to 16 cubits till the 19th of September ;
the confequence of which was that the country wras de¬
populated by famine and peftilence.
We may eafily imagine that the Nile cannot over¬
flow the whole country of itfelf in fuch a manner as to
render it fertile ; for which reafon there are innumer¬
able canals cut from it acrofs the country, it has al¬
ready been obferved, by which the water is convey¬
ed to dillant places, and almoft every town or village
has one of thefe canals. In thofe parts of the country
where the inundation does not reach, and where more
water is required than it can furnilh, as for watering of
gardens, they mult have recourfe to artificial means^ for
railing it from the river. In former times they made
ufe ol Archimedes’s fcrew ; but that is now difufed,
and in place of it they have chofen the Perfian w heel.
This is a large wheel turned by oxen, having a rope
hung with feveral buckets which fill as it goes round,
and empty themfelves into a ciltern at the top. Where
the banks of the river are high, they frequently make
a bafon in the fide of them, near which they fix an up-
right pole, and another with an axle acrofs the top of
that, at one end of which they hang a great done, and
at the other a leathern bucket; this bucket being drawn
down into the river by twro men, is raifed by the defcent
of the done, and emptied into a cidern placed at a pro¬
per height. This kind of machine is ufed chiefly in the
upper parts of the country, where the raifing of wrater
is more difficult than in places near the fea. When any
of the gardens or plantations want water, it is conveyed
from the cilferns into little trenches, and from thence
condudled all round the beds in various rills, which the
gardener eafily dops by raifing the mould againd them
wfith his foot, and diverts the current another way as he
fees occafion.
The rife of the inundation is meafured, as has alrea¬
dy been obferved, by an indrument adapted for the
purpofe, and called mikeas, which wTe trandate nilometer.
Mr Bruce informs us, that this is placed between Geeza
and Cairo, on the point of an illand named Rhoila,
about the middle of the river, but fomewhat nearer
to Geeza. It is a round towrer with an apartment, in
the middle of which is a cidern neatly lined with mar¬
ble. The bottom of this cidern reaches to that of the
river, and there is a large opening by wffiich the w'ater
has free accefs to the infide. The rife of the water is
indicated by an oftagonal column of blue and wffiite
marble, on which are marked 20 peeks or cubits of 22
inches each. The two lowermod of thefe have no fub-
[ 624 ]
£ G Y
Egypt.
divifions; but each of the red is divided into 24 parts
called digits; the whole height of the pillar being 36'
feet 8 inches.
When the river has attained its proper height, all the Of thefe a
canals are opened, and the wdiole country laid under wa-nalsby
ter. During the time of the inundation a certain vor-wfik'h the
tical motion of the waters takes place : but notwith-water *s
danding this, the Nile is fo eafily managed, that many
fields low’er than the lurface of its waters are preferved
from injury merely by a dam of moidened earth not
more than eight or ten inches in thicknefs. This me¬
thod is made ufe of particularly in the Delta when it is
threatened with a riood.
As the Nile does not always rife to a height fuffi-
cient for the purpofes of agriculture, the former fove-
reigns of Egypt were at vad pains to cut proper ca¬
nals in order to fupply the deficiency. Some of thefe
are dill preferved, but great numbers are rendered ufe-
lefs through the indolence or barbarity of their fuccef-
fors. Thofe which convey the water to Cairo, into the
province of hayoom, and to Alexandria, are bed taken
care of by government. The lad is watched by an
officer/ appointed for that purpofe, whofe odice it is to
hinder the Arabs of Bachria, wffio receive this fuper-
fluous W'ater, from turning it off before Alexandria be
provided for, or opening it before the proper time,
which would hinder the increafe of the river. In like
manner, that which conveys the w^ater to Fayoom is
w'atched, and cannot be opened before that of Cairo,
■which is called the Canal of Trajan. A number of
other canals, only taken care of by thofe who derive
advantage from them, proceed from that arm of the
Nile W'hich runs to Damietta, and fertilize the pro¬
vince of Sharkia; which, making part of the idhmus
of Suez, is the mod confiderable of Egypt, and the
mod capable of a great increafe of cultivation. The
plains of Gaza wffiich lie beyond, and are poffeffed by
the Arabs, would be no lefs fertile, were it not for the
excedive inclination thele people have to dedroy, fo that
they make war even wdth the fpontaneous productions
of the earth. A number of other canals run through
the Delta ; and the vediges of thofe which watered the
provinces to the eadw'ard and wedward, diow that in
former times thefe wTere the bed cultivated parts of
Egypt. “ We may alfo prelume (fays the baron de
'lott), from the extent of the ruins of Alexandria, the
conltruClion of the canal, and the natural level of the
lands which encompafs the lake Mareotis, and extend
themfelves wedwrard to the kingdom of Barca, that this
country, at prefent given up to the Arabs, and almod
defert, was once lufficiently rich in productions of eve¬
ry kind to furnifh the city of Alexander w ith its whole
fubfidence.”
The air and climate of Egypt are extremely hot, Air and
not only from the height of the dm, which in dimmerc,imate
approaches to the zenith, but from the wrant of rain and ^yi*’
from the vicinity of thofe burning and fandy deferts
which lie to the fouthwTard. In the months of July and
Augud, according to M. Volney, Reaumur’s thermo¬
meter dands, even in the mod temperate apartments,
at the height of 24 or 25 degrees above the freezing
point; and in the fouthem parts it is faid to rife dill
higher. Hence, he fays, only two feafons fhould be
didinguidied in Egypt, the cool and the hot, or fpring
and dimmer. The latter continues for the greated part
of
Egypt.
E G Y t 625 ]
of the year, viz, from March to November or even breathed
' longer j for by the end of February the fun is intoler¬
able to a European at nine o’clock in the morning.
During the whole of this feafon, the air feems to be
inflamed, the Iky fparkles, and every one fvveats pro-
fufely, even without the lead exercife, and when cover¬
ed with the lighted drefs. • This heat is tempered by
the inundation of the Nile, the fall of the night dews,
and the fubfequent evaporation 5 fo that fome of. the
European merchants, as well as the natives, complain of
the cold in winter. The dew we fpeak of does not fad
regularly throughout the fummer, as with us; the
parched date of the country not affording a fuflicient
quantity of vapour for this purpofe. It is fird ob-
ferved about St John’s day (June 24th), when the river
has begun to fwell, and confequently a great quantity
of water is railed from it by the heat of the fun,, which
beincr foon condenfed by the cold of the night air, falls
down in copious dews.
It might naturally be imagined, that as for three
months in the year Egypt is. in a wet and mardiy
fituation, the exceflive evaporation and putrefaction of
the dagnating waters would render it very unhealthy.
But this is by no means the cafe. The great drynefs
of the air makes it abforb vapours of all kinds .with the
utmod avidity} and thefe riling to a great height, are
carried off by the winds either to the fouthward or
northward, without having time to communicate any
of their pernicious effefts. This drynefs is fo remark¬
able in the internal parts of the country, that fle.fli meat
expofed to the open air does not putrefy even in fum¬
mer, but foon becomes hard and dry like wood. In the
defects there are frequently dead carcafes thus dried in
fuch a manner, and become fo light, that one may ea-
fdy lift that of a camel with one hand. . In the mari¬
time parts, however, this drynefs of the air is not to be
expefled. They difeover the fame degree of moifture
which ufually attends fuch lituations. At Rofetta and
Alexandria, iron cannot be expofed to the air for 24
hours without ruffing. According to M. Vo.lney, the
air of Egypt is alfo ftrongly impregnated with falls :
for which opinion he gives the following reafon ; “ The
ftones are corroded by natrum (mineral alkali or foda),
and in moift places long cryftallizations of it are to be
found, which might be taken for faltpetre. I he wfa.ll of
the Jefuits garden at Cairo, built with earth and bricks,
is everywhere covered wdfh a cruft of this natrum as thick
as a crown piece: and when this garden has been over¬
flowed by the waters of the kalidj (canal),, the ground,
after they have drained off, appears fparkling on e\eiy
fide with cryftals, which certainly w^ere not brought
thither by the water, as it Ihows no lign of fait either
to the tafte or by diilillation.”-—But whatever may be
the quantity of fait contained in the earth, it is certain
that M. Volney’s opinion of its coming thither from
the air cannot be juft. I he fait in queftion is excef-
fively fixed, and cannot be diflipated into the air writh-
out the violent heat of a glafshoufe furnace ; . and even
after this has been done, it wall not remain diflufed
through the atmofphere, but quickly falls back again.
No experiments have ever fhown that any fait was or
could be diffufed in the air, except volatile alkali, and
this is now7 known to be formed by the union of two
permanently elaftic fluids •, and it is certain that a fa-
Ene air would quickly prove fatal to the animals who
Vol. VII, Part II.
EjrypG
148
E G Y
„ it. The abundance nf this kind of fait in
Egypt therefore only (hows, that by fome unknown
operation the heat of the fun forms it from the two in¬
gredients of earth and water, though we do not yet un-
derftand the manner, nor are able to imitate this natural
operation. •
To this faline property of the earth M. \olney a-Why exotic
feribes the exceflive quicknefs of vegetation m Egypt,
which is fo great, that a fpecies of gourd called kara^ Egypt,
will, in 24 hours, fend forth fhoots of four inches m
length j but for the fame reafon, in all probability, it is
that no exotic plant will thrive in Egypt. Fne mei-
chants are obliged annually to fend to Malta for their
garden feeds j for though the plants thrive very well at
firft, yet if the feed of them is preferved, and Town
a fecond year, they always come up too tall and
flender. .
By reafon of the great drynefs of the air, .Egypt is
exempted from the phenomena of rain, hail, inow',
thunder, and lightning. Earthquakes are alio leldoni
heard of in this country j though foraetimes they
have been very fatal and deftru&ive, particularly one
in the year 1112. In the Delta, it never rains in
fummer, and very feldom at any other time. In 176*,
however, fuch a quantity of rain unexpectedly tell,
that a great number of houfes, built with mudwalls,
tumbled entirely down by being foaked with the
wrater, to which they were unaccuftomed. In the
Higher Egypt the rain is ftill lefs frequent; but the
people, fenfible of the advantages which accrue from
it, always rejoice when any falls, however infufficient 149 _
to anfwer the purpofe. This deficiency of rain Is ^
fupplied by the inundation and dews already men-£ t.
tioned. The latter proceed, as has already been
faid, partly from the waters of the inundation and
partly from the fea. At Alexandria, after fun-
fet, in the month of April, the clothes expofed to the
air on the terraces are foaked with them as ii it had
rained. Thefe dews are more or lefs copious accord¬
ing to the direction of the wand. Bhey are produced
in the greateft quantity by the wefterly and northerly
winds, which blow from the fea } but the fouth and
fouth-eaft winds, blowing over the deferts of Africa and
Arabia, produce none. < 150
'J'be periodical return of winds from a certain quar-R.eniark-
ter is a very remarkable phenomenon in this country, able re|u-^
When the fun approaches the tropic of Cancer, they wjn(jSi>
ftiift from the eaft to the north •, and, during the
month of June, they always blow from the north or
north-weft. They continue northerly all the month
of July, varying only fometimes towards the eaft, and
fometimes the contrary way. About the end of this
month, and during the whole of Auguft and Sep¬
tember, they blow diredHy from the north, and are
but of a moderate ftrengtb, though fomewhat weaker
in the night than in the day. Towards the end of
September they return to the eaft, though they do not
abfolutely fix on that point, but blow more regularly
from it than any other except the north. As the fun
approaches the fouthern tropic, they become more va¬
riable and tempeftuous, blowing moft commonly from
the north, north-eaft, and weft, which they continue to
do throughout the months of December, January, and
February, and, during that feafon,. the vapours raifed
from the Mediterranean condenfe into miff, or even
4 K fometimes
%ypt.
E G Y [ 6
fometlmes into rain. Towards tlie end of February,
and in the fucceeding month, they more frequently blow
from the fouth than from any other quarter. l)urirrr
fome part of the month of March and in that of Aprif,
they blow from the fouth, fouth-eaft, and fouth-weft ;
lometimes from the north and call, the latter beco¬
ming moft prevalent about the end of that month, and
continuing during the whole of May.
It is to the long continuance of the north winds,
formerly called the Etejian winds, that Egypt proba-
men'a oY" ^ °'ves its extreme drynefs, as well as part 'of the in-
caJioned by undation b7 which it is fertilized. From the month
twooppo- April to July, there appear to be two immenfe cur-
lite currents rents in the atmcfphere, the under one blowing from
Rains in
.Abyffinia
vt air’ the north, and the upper from the fouth. By the for-
mer the vapours are raifed from the Mediterranean and
louthern parts of Europe, where they are carried over
Abyflinia, diiTolvmg there in immenfe deluges of rain ;
while by the latter the fuperfluous vapours, or thofe
raifed from the country of Abyffinia itfelf, are carried
northward toward the fources of the Euphrates.
Here the clouds coming from the fouth, defcending
into the lower part of the atmofphere, diffolve in like
manner into rain, and produce an inundation of the
Euphrates fimilar to that of the Nile, and immediately
fucceeding it. Mr Bruce had an opportunity of afcer-
taining this fa£l in the month of June 17685 for at that
time, while on a voyage from Sidon to Alexandria, he
obferved great numbers of thin white clouds moving
rapidly from the fouth, and in direct oppolition to the
Eteftan winds.
Befides the ordinary winds here fpoken of, Egypt is
infefted with the deftrudtive blafts common to all warm
countries which have deferts in their neighbourhood.
I hefe have been diftinguiffied by various names, fuch
152 aspoijonous winds, hot winds of the defert, Samiei, the
Of the hot wind of Damafcus, Katnfn, and Simoom. In Egypt they
winds. are denominated “ winds of 50 days,” becaufe they
moft commonly prevail during the 50 days preced¬
ing and following the equinox ; though, fliould they
blow conftantly during one half of that time, an uni-
verfal deftrubtion would be the confequence. Of thefe
travellers have given various defcriptions. M. Volney
fays, that the violence of their heat may be compared
to that of a large oven at the moment of drawing out
the bread. They always blow from the fouth j and are
undoubtedly owing to the motion of the atmofphere
over fuch vaft trabls of hot fand, where it cannot be
fupplied by a fufficient quantity of moifture. When
they begin to blow, the iky lofes its ufual ferenity, and
affumes a dark, heavy, and alarming afpebt, the fun
himfelf laying aftde his ufual fplendor, and becoming of
a violet colour. This terrific appearance feems not to
be occafioned by any real haze or cloud in the atmo¬
fphere at that time, but folely to the vaft quantity of
fine fand carried along by thofe winds, and which is fo
exceffively fubtile that it penetrates everywhere. The
motion of this wind is always rapid, but its heat is not
intolerable till after it has continued for fome time. Its
pernicious qualities are evidently occafioned by its ex-
ceffive avidity of moifture. Thus it dries and flirivels
up the Ikin 5 and by doing the fame to the lungs, will
in a Ihort time produce fuffocation and death. The dan¬
ger is greateft to thofe of a plethoric habit of body, or
who have been exhaufted by fatigue 5 and putrefablion
26 ] E G Y
foon takes place in the bodies of fuch as are deftroyed
by it. Its extreme drynefs is fuch, that water fprink-
led on the floor evaporates in a few minutes 5 all the
plants are withered and ftripped of their leaves 5 and a
fever is inftantly produced in the human fpecies by the
luppreffion of peifpiration. It ufually lafts three days,
but is altogether infupportable if it continue beyond
that time. The danger is greateft when the wind
bloses in fqualls, and to travellers who happen to be
expofed to its fury without any flicker. The beft me¬
thod in this cafe is to flop the nofe and mouth with an
handkerchief. Camels, by a natural inftinbl, bury
their nofes in the fand, and keep them there till the
fquall is over. The inhabitants, who have an oppor¬
tunity of retiring to their houfes, inftantly ftmt them-
felves up in them, or go into pits made in the earth, till
the deftrublive blaft be over.
The defcription of a blaft; of this kind which over¬
took Mr Bruce in the defert of Nubia is ftill more ter¬
rible than that juft given from M. Volney. We have
already mentioned fomething of the pillars of moving
fand raifed by the winds in the defert. Thefe were ob¬
ferved by our traveller on this occafion in all their ter¬
rific majefty. Sometimes they appeared to move (low¬
ly ; at other times with incredible fwiftnefs, fo that
they could not have been avoided by the fleeteft horfe.
Sometimes they came fo near, that they threatened de-
ftrubtion to the whole company. Frequently the tops,
when arrived at an immenfe height, fo that they
wrere loft in the clouds, fuddenly feparated from the
bodies, and difperfed themfelves in the air 5 and
fometimes the whole column broke off near the mid¬
dle, as if it had received a cannon (hot 5 and their
fize was fuch, that at the diftance of about three
miles, they appeared ten feet in diameter. Next day
they appeared of a fmaller fize, but more numerous,
and fometimes approached wuthin twTo miles of the
company. The fun was now obfcured by them, and
the tranimiffion of his rays gave them a dreadful ap¬
pearance refembling pillars of fire. This was pro¬
nounced by the guide to be a fign of the approaching
Simoom or hot wind 5 and he direbled, that when it came,
the people Ihould fall upon their faces and keep their
mouths on the fand, to avoid the drawing in this per¬
nicious blaft with their breath. On his calling out
that the Simoom was coming, Mr Bruce turned for a
moment to the quarter from whence it came, which
was the fouth-eaft. It appeared like a haze or fog of
a purple colour, but lefs bright than the purple part
of the rainbow 5 feemingly about 20 yards in breadth,
and about 1 2 feet high from the ground. It moved
with fuch rapidity, that before he could turn about and
fall upon his face, he felt the vehement heat of its cur¬
rent upon his face 5 and even after it paffed over,
which was very quickly, the air which followed w as of
luch a heat as to threaten fuffocation. Mr Bruce had
unfortunately infpired fome part of the pernicious
blaft 5 by which means he almoft entirely loft his voice,
and became fubjeft to an afthmatic complaint, from
wdiich he did not get free for two years. The fame pheno -
menon occurred twice more on their journey through
this defert. The fecond time, it came from the fouth a
little to the eaft : but it now feemed to have a (hade of
blue along with the purple, and its edges were lefs per-
fe<ftly defined 5 refembling rather a thin fmoke, and ha-
E G Y
t 627 ]
E C Y
F.eypt. ving about a yard in the middle tinged with blue and
' -v   purple. The third time, it was preceded by an appear¬
ance of Tandy pillars more magnificent than any they
had yet obferved ; the fun finning through them in
fuch a manner as to give thofe which were nearefi a re-
femblance of being fpangled with ftars of gold. The
fimoom which followed had the fame blue and purple
appearance as before, and was followed by a molt fuf-
focating wind for two hours, which reduced our travel¬
lers to the loweft degree of weaknefs and defpondency.
It was remarkable that this wind always came from the
fouth-eaft, while the Tandy pillars, which prognoftica-
ted its approach, affe&ed to keep to the weftward, and
to occupy the vail circular fpace inclofed by the Nile to
the weft" of their route, going round by Chagre to¬
wards Dongola. The heaps of fand left by them
when they fell, or raifed by the whirlwinds which car¬
ried them up, were 12 or 13 feet high, exadlly coni¬
cal, tapering to a fine point, and their bafes well pro-
153 portioned.
Of the in- The inhabitants of Egypt may now be difiinguilhed
habitants of jnto four races Qf people.
j The Arabs, who may be fubdivided into three
claffes. I. The pofterity of thofe who fettled here
immediately after the conqueft of the country by
■Amrou Ebn A1 As, the khalif Omar’s general. 2. The
Magrebians, or Weftem Arabs, who at different times
have migrated from the countries to the weftward
of Egypt, and are defcended from the Saracen con¬
querors of Mauritania. 3. The Bedouins, or Arabs
of the defert, known to the ancients by the name of
Scemtes, or dwellers in tents. 1 he firft of thele claffes
are now found among the hufbandmen and artizans 5
and are diftinguiftied from the others by being oi a
more robuft habit of body, as well as of a larger fta-
ture than the others. They are in general five feet
four inches high ; and many of them attain two or three
inches more, and are mufcular without being fiefhy.
Their countenances are almoft black, but their features
are not difagreeable j and as thofe of the country do not
ally themfelves in marriage but with the people of their
own tribe, their faces have all a ftrong relemblance to
each other. This is not the cafe with fuch as live in
towns, by reafon of their promifcuous marriages. Phe
fecond clafs are more numerous in the Said, where they
have villages and even diftindl fovereigns of their own.
Eike the former, they apply themfelves to agriculture
and mechanical occupations. Phe Bedouins pafs their
lives among the rocks, ruins, and fequeftrated places
where they can find water ; fometimes uniting in tribes
and living in low fmoky tents, and ftiifting their ha¬
bitations from the defert to the banks of the river and
back again, as beft fuits their conveniency. I heir
time of inhabiting the defert is the fpring •, but after the
inundation they take up their refidence in Egypt, in or¬
der to profit by the fertility of the country. Some farm
lands in the country, which they cultivate, but change
annually. In general, all thefe Bedouins are robbers,
and are"^ a great terror to travellers as well as to the huf¬
bandmen j but though their number is eftimated at
not lefs than 30,000, they are difperfed in fuch a
manner that they cannot attempt any thing of confe-
quence.
II. The Copts are defendants of thofe inhabitants of
Egypt whom the Arabs fubdued, and who were com-
pofed of original Egyptians, Ferfians and Greeks. M.
Volney is of opinion that their name of Copts is only
an abbreviation of the Greek word Aigouptios, an
Egyptian. They are principally to be met with in the
Said, though fome alfo inhabit the Delta. They have
all a yellowilh duiky complexion, puffed-up vifage,
fwoln eyes, flat nofes, and thick lips } and in fail the
exaft countenance of a mulatto. M. Volney, from a
view of the fphynx, and finding its features to be fuch
as is juft now defcribed, concludes, that the ancient E-
gyptians were real negrqes 5 which he thinks is likewife
confirmed by a paffage in Herodotus, where he con¬
cludes, that the inhabitants of Colchis were defcended
from the Egyptianr, “ on account of the blacknefs of
their fkins and frizzled hair.” M. Volney alfo re¬
marks, that the countenance of the negroes is fuch as
exactly reprefents that ftate of contraction affumed
by our faces when ftrongly affected by heat. Phe
eye-brows are knit, the cheeks rife, the eye-lids are
contracted, and the mouth diftorted j and this ftate
of contraction to which the features of the negroes
are perpetually expofed in the hot climates they in¬
habit, is become particularly charaCteriftic. Excef-
five cold and fnow produces the fame effeCt j and hence
this kind of countenance is alfo common among the
Tartars j while, in the temperate climates, the features
are proportionably lengthened, and the whole counte¬
nance expanded.
The Copts profefs the Chriftian religion, but follow
the herefy of the Eutychians, whence they have beeii
perfecuted by the Greeks 5 but having at laft got the
better of their adverfaries, they are become the depofi-
taries of the regifters of the lands and tribes. At Cairo
they are called writers ; and are the intendants, fecre-
taries, and collectors for government. The head of
their clafs is writer to the principal chief j but they are
all hated by the Turks, to whom they are flaves, as
well as by the peafants whom they opprefs. P'heir
language bears a great refemblance to the Greek ; but
they have five letters in their alphabet, as well as a
number of words in their language, which may be con-
fidered as the remains of the ancient Egyptian. Thefe are
found to bear a near refemblance to the dialeCts of fome
of the neighbouring nations, as the Arabic, Ethiopian,
Syriac, &c. and even of thofe who lived on the banks of
the Euphrates. The language of the Copts, however,
has fallen into difufe for upwards of 300 years. On
the conqueft of the country by the Saracens, the latter
obliged the people to learn their language j and about
the year 722 the ufe of the Greek tongue was prohi¬
bited throughout the whole of their empire : the Ara¬
bic language then of courfe became univerfal j while
the others, being only met with in books, foon became
totally negleCted. P'he true Coptic, therefore, though
there is a tranfiation of the fcriptures and many books
of devotion written in it, is underftood by nobody, not
even the monks and priefts.
III. The Turks, who have the title of being maflers
of Egypt, but are chiefly to be met ryith at Cairo, where
they poffefs the religious and military employments.
Formerly they poffeffed alfo the ports under govern¬
ment 5 but thefe are now occupied by the fourth race of
inhabitants, viz.
IV. The Mamlouks. Of the origin of thefe we have
already given fome account: we have only, there-
4 K 2 fore.
Egypt.
\
E G Y [ 628 ] E G Y
Egypt.
*54
Abfurd
tlrefs and
accoutre¬
ments of
the Mam-
louks.
fore, to relate forae of the molt remarkable particulars
concerning their conftitution and government, man¬
ners, &c.
Thefe people, as has already been mentioned, are
the real mailers of Egypt; -and in order to iecure them-
lelves in the poffeflion of the country, they have taken
icveral precautions. One of the principal of thefe is
the degradation of the two military corps of azabs
and janizaries, both of which were formerly very for¬
midable. They have been able to effeft this only in
confequence of the corrupt and wretched government
of the Turks $ for before the revolt of Ibrahim Kiaya,
the Turkiih troops, which ought to have coniiited
of 40,000, were reduced to leis than half that num¬
ber through the avarice and malverfation of their
officers. Their degradation was completed by Ali Bey j
who having firil difplaced all the officers who gave him
any umbrage, left their places vacant, acd fo reduced
the confequence of the whole, that the azabs and ja¬
nizaries are now only a rabble of vagabonds, who dread
the Mamlouks as much as the meaneli of the populace.
The principal body of the Mamlouks refide at Cairo 5
but many of them are difperfed through the country, in
order to keep up their authority, collect the tribute,
and opprefs the people : yet it ihould feem very eafy
for the Porte to difpoffefs them of this ufurped autho¬
rity, as their number is fuppofed not to exceed 8500,
including among thefe a great many youth under 20
years of age.
The Mamlouks are all horfemen j and as war is ac¬
counted the only honourable employment among them,
it is reckoned difgraceful to walk on foot, none but
cavalry being accounted foldiers. The other inha¬
bitants are allowed only the ufe of mules and affes ;
and the fame mark of indignity is impofed upon Eu¬
ropeans $ though by proper management and liberal
prefents, this may be got over. In the year 1776
Lord Algernoun Percy, afterwards Lord Louvaine, and
the earl of Charlemount, obtained permiffion to ride up¬
on horfeback. The Mamlouks, however, are not incited
to this continual appearance on horfeback merely by
their fuppofed fuperiority to the reit of the inhabitants j
it is rendered neceffary by their drefs, which is extreme¬
ly unwieldy and cumberfome. It tonfiils of a wide
ffiirt of thin yellowith-coloured cotton j over which is
a gown of Indian linen, or fome of the light Huffs of
Damafcus or Aleppo. Over this is a fecond covering
of the fame form and widenefs, with fleeves reaching
down to the ends of the fingers. The former covering
is called antari, and the latter caftan. The'caftan is
ufually made of filk or fome finer fluff than the un¬
der garments $ and both of them are fallened by a
long belt, which divides the whole drefs into two
bundles. Over all thefe they have a third, named djou-
ha, confifling of cloth without lining, and made
nearly fimilar to the others, but that the fleeves are
cut in the elbow. This coat is lined, fcmetimes even
in fummer, with fur j and as if all this was not fuffi-
cient, they have an outer covering called the beniche,
which is the cloak or robe of ceremony ; and fb com¬
pletely covers the body, that even the ends of the fingers
are not to be feen. Thus, when the beniche and other
accoutrements are on, the whole body appears like a
long fack, with a bare neck and bald head covered
with a turban thruft out of it. This turban is cabled
a kaouk; and is of a cylindrical form, yellow, and Ejnpt.
turned up on the outlide with a roll of muffin artifici- y-——>
ally folded up. On their feet they have a lock of yel¬
low leather reaching up to the heels, flippers without
any quarters, which confequently are always ready to be
left behind in walking. Lailly, to complete this extra¬
ordinary drefs, they have a kind of pantaloon or trow-
fers, long enough to reach up to the chin, and fo large
that each of the legs is big enough to contain the whole
body ; but that they may walk more at their eafe un¬
der fuch a number of impediments, they tie all the
loofe parts of their drefs with a running falh. “ Thus
fwaddled (fays M. Volney), we may imagine the Mam¬
louks are not very ablive walkers *, and thofe who are
not acquainted by experience with the prejudices of dif¬
ferent countries, will find it fcarcely poffible to believe
that they look on this drefs as exceedingly commodi¬
ous. In vain wre may objeft that it hinders them from
walking and encumbers them unneceffarily on horfe¬
back j and that in battle a horfeman once difmounted
is a loll man. They reply, It is the cujlom, and every
objeblion is anfwered.”
In the accoutrements of their horfes, the Mamlouks
are almoil equally abfurd. The faddle is a clumfy piece
of furniture, weighing with the faddle-cloths not lefs
than 25 pounds 5 while the weight of the ilirrups is
never lefs than 9 or 10 pounds, nay, frequently ex¬
ceeds 13. On the back-part of the faddle rifes a truf-
fequin about eight inches in height, while a pummel
before projects four or five inches, in fuch a manner
as to endanger the breaft of the horfemen if he ihould
happen to Hoop. Inllead of a fluffed frame, they have
three thick woollen coverings belowr the faddle j the
whole being fallened by a furcingle, which, inllead of
a buckle, is tied with leather thongs in very complica¬
ted knots, and liable to flip. Inllead of a crupper
they have a large martingale which throws them upon
the horfes Ihoulders. The ilirrups are made of copper,
longer and wider than the foot, having circular edges
an inch high in the middle, and gradually declining to¬
ward each end. The edges are ffiarp, and ufed inllead
of fpurs, by which means the poor animal’s fides are
much wounded. The weight of the furniture has al¬
ready been mentioned j and is the more ridiculous as
the Egyptian horfes are very fmall. The bridle is
equally ill contrived, and greatly injures the horfe’s
mouth, efpecially by reafon of the violent method they
have of managing the animal. Their uiual way is to
put the horfe to a full gallop, and fuddenly Hop him
when at full fpeed. Thus checked by the bit, he bends
in his hind legs, fliffens the fore ones, and moves along
as if he fcarce had joints in his body : yet, notwithiland-
ing all thofe difadvantages, our author acknowledges
that they are vigorous horfemen, having a martial ap¬
pearance which pleafes even llrangers. ^ e
In the choice of their arms they have Ihown them- Thefr'arms
felves more judicious. Their principal weapon is an education,
Engliffi carbine about 30 inches long j but fo large in^0*
the bore, that it can dilcharge 10 or 1 2 balls at a time,,
which can fcarcely fail of doing great execution even
from the moll unfldlful hand. Befides two large pif-
tols carried in the belt, they have fometimes a heavy
mace at the bowT of the faddle for knocking down their
enemy ; and by the ffioulder belt they fufpend a crook¬
ed fabre meaffiring 24 inches in a Hraight line from the
hilt
E G Y [ 629 ] E G ^ " r .
30 at kail in the curve. The feem convinced that their patrons are
Egypt.
Egypt, hilt to the point, but  -- - ,,, .
—v reafon of the preference given to the crooked blade is,
that the effea of a ftraight one depends merely on he
force with which it falls, and is confined to a imall
fpace, but that of a crooked one is continued longer
by the action of the arm in retiring. The Mamlouks
commonly procure their fabres from Conftantmcjple
or other parts of Europe •, but the beys rival each oJier
in thofe of Perfia and fuch as are fabricated of the an¬
cient fteel of Damafcus. For thefe they frequently
pay as high as 40I. or 50I. fterling *, but though 1
muft be allowed that the edge of thefe weapons is
exquifitely keen, yet they have the defecl; of being
almoft as brittle as glafs. The whole education and
employment of the Mamlouks confifts m the exercife
of thefe weapons, or what is conducive to it 5 io that
we fhould imagine they might at laft become altoge¬
ther irrefiftible. Every morning the greater part of
them exercife themfelves in a plain near Cairo, by hung
their carbines and piftols in the moll expeditious man¬
ner, having an earthen veffel for a mark to ftioot at j
and the perfon who breaks it is highly applauded by
the beys who attend in order to encourage them. Here
alfo they exercife themfelves in the me o. the fabre, as
well as of the bow and arrows j though they do not any
longer make ufe of thefe laft in their engagements. 1 heir
favourite diverfion is throwing the Jjend; a word pro¬
perly fignifying a reed, but which is generally made
ufe of to fignify any ftaff thrown by the hand after the
manner of the Roman pilum. In this exercife they
make ufe of the branches of the palm-tree frefti ftnpped.
Thefe branches, which have the form of the ftalk ot an
artichoke, are about four feet long, and weigh five or
fix pounds. With thefe the cavaliers enter the hits,
riding full fpeed, and throwing them afterwards at
each other from a confiderable difiance. As foon
as the affailant has thrown his weapon, he turns his
horfe, and his antagonift purfues in his turn, f he di¬
verfion, however, frequently turns out very fenous, as
. fome are capable of throwing thefe weapons with force
Ate not fufficient to wound their antagomlfs mortally Ah
formidable Bey was particularly dexterous at this kmdot fport
and frequently killed thofe who oppofed him. Ail
thefe military exercifes, however, are by no means luf-
ficient to render the Mamlouks formidable in the field.
In their engagements they have neither order, d\ici-
pline, nor even fubordination •, fo that their wars are
only fcenes of robbery, plunder, and tumultuary en¬
counters, which begin very often fuddenly in the ffreets
of Cairo without the leaft warning. If the contention
happens to be transferred to the country, d is 1 car
ried on in the fame manner. The ftrongeft or moft
daring party purfues the other. If they are equal m
courage, they will perhaps appoint a field of battle,
and that without the leaft regard to advantages of li-
tuation, but fighting in platoons, with the boldelt
champions at the head of each. After mutual defian¬
ces, the attack begins, and every one choofes out his
man. After difcharging their fire-arms, if they have
an opportunity they attack with their fabres } and
fuch as happen to be difmounted are helped up again
by their fervants *, but if nobody happens to be near,
the fervants will frequently kill them for the lake of the
money they carry about them. Of late, however,
the ordinary Mamlouks, who are all Hares to the red,
m war.
r57
cipally interefted 5 for which reafon they reafonao y
enoup-h conclude that they ought to encounter the great-
eft dangers. Hence they generally leave them to carry
on the difpute by themfelves *, and being always fure of
finding a mafter who will employ them, they generally
return quietly to Cairo until fome newr revolution takes
The mode oflivinff among the Mamlouks is exceed-Thek W-
ingly expenfive, as may cafily be conceived from 'vhatPp^y
has already been related. There is. not one of tnem
who does not coft above look fterling annually, and
many of them upv/ards of 200I. At every return
of the faft of Ramadan, their, mailers muft give
them a new fuit of French and Venetian clothes, with
fluffs from India and Damafcus. Frequently they re¬
quire new horfes and harnefs : they muft hkewife have
piftols and fabres from Damafcus, with gilt ftirrups and
fuddles and bridles plated with filver. .The chiefs are
diftinguifhed from the vulgar by the trinkets and pie-
cious ftones they wrear ; by riding Arabian horfes of
200I. or 300I. value, wearing fhawls of Cathmire m
value from 25I. to 50I. each, with a variety of pehffes,
the cheapeft of which coils above 20I. Even the Eu¬
ropean merchants have given into this kind of. extra¬
vagance j fo that not one of them looks upon his war¬
drobe to be decently fumifhed unlefs it be in value
500I. or 600I.
Anciently it was cuftomary for the women to adorn
their heads with fequins •, but this is now rejetted as
not fufticiently expenfive. Inftead of thefe, diamonds,
emeralds, and rubies, are now fubftituted *, and to thefe
they add French fluffs and laces. In other refpetts
the charatter of the Mamlouks is almoft the.worfl I5g
that can be imagined. Without affettion, tie, or Their bad
connettion with each other or with the reft of man-c ara
kind, they give themfelves up without controul to the
moft’ enormous vices ; and, according to M. Volney,
they are at once ferocious, perfidious, feditious, bale,
deceitful, and corrupted by every fpecies of debauch-
ery, not excepting even the unnatural vice of which
he tells us not one is free, this being the veiy firlc
leffon each of them receives from his mafter,: all being
originally {laves, as has already been mentioned. 159
As thefe are the prefent governors of Egypt, weMiferable
may eafily judge that the condition of the commonftatettthe.
people cannot be very agreeable. The greater part
of the lands indeed are in the hands of the Mamlouks,
beys, and profeffors of the law, the property of all
others being very precarious. Contributions are to be
paid, or damages repaired, every moment; and there
is neither right of fucceflion nor inheritance for real
property, but every thing muft be purchafed from go¬
vernment. The peafants are allowed nothing but what
is barely fufficient to fuftain life. They cultivate, rice
and corn indeed, but are not at liberty to ufe either.
The only food allowed them is dora or Indian millet,
from which they make a kind of taftelefs bread •, and
of this, with water and raw onions, confifts all their
fare throughout the year, ffhey efteem themfelves
happy, therefore, if along with thefe they can fometimes
procure a little honey, cheefe, lour milk, or a few
dates. They are very fond of flefli meat and fat .; nei¬
ther of which, however, they have an opportunity of
except at extraordinary feftivals. I heir or¬
dinary
tailing
Egypt.
t6o
Difeafes
prevalent
in this
tountry.
. E G Y [ 630
dlHfr>' rdre^ confirts a fhiit of coarfe blue linen, and
a clumfy black cloak j with a fort of black bonnet
over their heads ; and over all they wear a long red
woollen handkerchief. Their arms, legs, and breads,
are naked, and mod of them do not even wear draw¬
ers. 1 hey live m mud-walled huts of the mod mifer-
able condrudhon, where they are expofed to the in¬
conveniences of fmoke, heat,, and unwholefome air :
to all which are to be added the continual fears they
live m of being robbed by the Arabs, oppreffed by the
Mamlouks, or feme other grievous calamity. The on¬
ly converfation is concerning the intedine troubles and
milery of the country, murders, badinadoes, and exe¬
cutions. Here fentence of death is executed without
the lead delay or form of trial. The officers who go
the rounds m the dreets either by night or day, are
attended by executioners, who carry along with them
leathern bags for receiving the heads they cut off in
thefe expeditions.^ Even the appearance of guilt is
not neceffary to infer a capital punilhment j for fre¬
quently nothing more is requifite than the poffeffion of
wealth or being fuppofed to poffefs it. In this cafe
the unfortunate perfon is fummoned before fame bey j
and when he makes his appearance, a fum of money
is demanded of him. If he denies that he poffeffes it,
ie is thrown on his back, and receives two or three
mndred blows, on the foies of the feet, nay perhaps is
put to death without any ceremony. The only fecurity
of thofe who poffefs any wealth in this country there-
fore is, to preferve as great an appearance of poverty as
poffible. J
the climate of Egypt is far from being un¬
healthy j yet there are not a few difeafes which feem to
be peculiar to it, and to have their origin either from
tne conditution of the atmofphere, or the manner of
living of the inhabitants. One of thefe till lately has
been fuppofed to be the plague 5 which opinion we
find fupported by Hr Mead, who has endeavoured to
affign a natural reafon why it diould take its origin in
this country. But it is now univerfally agreed, that
the plague never originates in the interior parts of
kgypt* but always begins at Alexandria, paffing fuc-
ceffively from thence to Rofetta, Cairo, Damietta,
and the red of the Delta. It is likewife obferved, that
its appearance is always preceded by the arrival of fome
veffel from Smyrna or Condantinople ; and that if the
plague has been very violent in either of thefe cities,
the danger of Egypt is the greater. On proper in¬
quiry, it is found to be really a native of Condantinople j
from whence it is exported by the abfurd negligence
°u ^ ur^s’ yEo refufe to take any care to prevent
the fpreading of the infedion. As they fell even the
clothes of the dead without the lead: ceremony, and
mips laden with^ this pernicious commodity are fent to
.Alexandria, it is no wonder that it ffiould foon make
its appearance there. As foon as it has reached Cairo,
the European .merchants dmt themfelves up with their
amilies in their hhans or lodgings, taking care to have
no further communication with the city. Their pro-
vifions are now depofited at the gate of the khan, and
are taken up by the porter with iron tongs ; who
plunges them into a barrel of water provided for the
purpofe. If they have occafion to fpeak to any per¬
fon, they take care to keep at fuch a didance" as to
.avoid touching or even breathing upon each other.
] ’EG Y
By thefe precautions they certainly efcape the general
calamity, except by accident j and it not long ago
happened that the difeafe wms conveyed by a cat into
the. dwellings of the French merchants in Cairo 5 by
which two were infe&ed, and one died. In this man¬
ner they are imprifoned for three or four months,
without any other amufement than walking on their
terraces in the evenings, cards, or converfation with
one another, d here is a remarkable difference betwixt
tne plague, at Condahtinople and in Egypt. In the
former, it is mod violent in dimmer $ and in the latter
m winter, ending there always in the month of June,
t is alfo remarkable, that the water-carriers of Eaypt
whole backs are condantly wet from the nature of
their occupation, never have the plague. It ap¬
pears in Egypt every fourth or fifth year, when it
makes, fuch ravages as would depopulate the country
wrere it not for the vad concourfe of drangers which
arrive here every year from all parts of the Turkifli
empire.
A malady which feems in reality to be peculiar to
Egypt is blindnefs. This is fo common at Cairo, as
M. Volney informs us, that out of 100 people whom
he. has met on the dreet, he might reckon 20 quite
blind j 10 without the fight of one eye j and 20 o-
thers with their eyes red, purulent, or blemiffied.
Almod every one, fays he, wears a fillet, a token of
an approaching or convalefcent ophthalmy. In confi-
flering the caufes of this diforder, he reckons the fleftp-
ing uPon terraces to be a principal one. The fouth
wind, he fays, cannot be the caufe 5 otherwife the Be¬
douins ivould be equally fubject to it with the Egyp¬
tians thcmfelves : but what is with the greated proba¬
bility to be affigned as the caufe, according to our au¬
thor, is the very poor and little nutritive food which
the natives are obliged to ufe. “ The cheefe, four-
milk, honey, confeftion of grapes, green fruits, and
raw vegetables (fays he), which are the ordinary food
of the people, produce in the domach a diforder wdiich
phyficians have obferved to affecd the fight ; the raw
onions, efpecially, which they devour in great quan¬
tities, have a peculiar heating quality, as the monks
of Syria made me remark on myfelf. Bodies thus
nouriffied, abound in corrupted humours, which are
con.dantly endeavouring a difeharge. Diverted from the
ordinary channels, by habitual perfpiration, thefe hu¬
mours dy to the exterior parts, and fix themfelves where
they find the lead refidance. They therefore naturally
attack the head, becaufe the Egyptians, by (having it
once a-week, and covering it with a prodigioully hot
head.-drefs, principally attract to it the perfpiration ;
and if the head receives ever fo dight an impreffion of
cold on being uncovered, this perfpiration is fupprefs-
ed, and falls upon the teeth, or dill more readily on
the eyes as being the tendered part. It will appear
the more probable that the exceffive perfpiration of the
head is a principal caufe, when we refieft that the an¬
cient Egyptians, who went bare-headed, are not men¬
tioned by phyficians as being fo much affiidded wdth
ophthalmies j though w’e are informed by hidorians
that fome of the Pharaohs died blind. The Arabs of
the defert alfo, wrho cover the head but little, efpe¬
cially when young, are alfo very little fubjedt to them.’
In this country blindnefs is often the confequence of
the fmall-pox, a diforder very frequent and very fa¬
tal
E G Y [ 631 ] E G Y
Egypt, tal among t’ne Egyptians j and no doubt the more
—v—' dangerous on account of their abfurd method of treai.-
ing it, of which it is needlefs to enter into any difeuf-
don in this place. ’X'hey are not unacouainted with
inoculation j but feein not to be fenlible oi its advanta¬
ges, as they very feldom pra£hfe it.
To the fame caufe, viz. unwholefome food, M. Vol-
ney aferibes the general deformity of the beggars, and
the miferable appearance of the children j which he
fays are nowhere fo wretched. “ Their hollow eyes,
pale and puffed faces, fwollen bellies, meagre extremi¬
ties, and yellow ikins, make them always feem as if
they had not long to live. Their ignorant mothers
pretend that this is the effect of the evil eye of fome
envious perfon, who has bewitched them j arid this an¬
cient prejudice is Hill general in Turkey : but the real
caufe is the badnefs of their food. In fpite of the ta-
lifmans, therefore, an incredible number of them pe-
riih } nor is any city more fatal to the population of the
neighbouring country than Grand Cairo.
The venereal difeafe, which, for reafons belt known
to themfelves, the inhabitants call the blejfed evil, is fo
general at Cairo, that one half of the inhabitants are
infeded. It is extremely difficult to cure, though the
fymptoms are comparatively very mild, infomuch that
people who are infected with it will frequently live to
the age of 80; but it is fatal to children born with the
infedion, and exceedingly dangerous to fuch as emi¬
grate to a colder climate.
Befides thefe, there are two uncommon difeafes met
with.in Egypt, viz. a cutaneous eruption which returns
annually ; and a fwelling of the teilicles, which often
degenerates into an enormous hydrocele. The former
comes on towards the end of June or beginning of Ju¬
ly, making its appearance in red fpots and pimples all
over the body, occafioning a very troublefome itch¬
ing. The caufe of this diftemper, in M. Volney’s
opinion, is the corruption of the waters of the Nile,
which towards the end of April become very putrid,
as has already been obferved. After this has been
drunk for fome time, the waters of the inundation,
which are frefh and wholefome, tend to introduce
fome change in the blood and humours j whence a cuta¬
neous eruption is the natural confequence.
The hydrocele moll commonly attacks the Greeks
and Copts ; and is attributed to the quantity of oil
they make ufe of, as well as to their frequent hot-
bathing. Our author remarks, that “ in Syria as
well as in Egypt, conllant experience has Ihown, that
brandy diililled from common figs, or from the fruit
of the fycamore tree, as well as from dates and the
fruit of the nopal, has a moft immediate effect on
the tellicles, which it renders hard and painful the
third or fourth day after it has been drunk ; and if
the ufe of it be not difeontinued, the diforder degene¬
rates into a confirmed hydrocele. Brandy diltilled
from dried railins has not the fame effect : this is al¬
ways mixed with anifeeds $ and is very llrong, being
diltilled three times. The Chriftians of Syria and
the Copts of Egypt make great ufe of it 5 the latter
efpecially drink whole bottles of it at their fupper. I
imagined this an exaggeration 5 but I have myfelf had
ocular proofs of its truth, though nothing could equal
my allonilhment that fuch exceffes do not produce in-
itant death, or at leait every fymptom of the molt in- Egypt-
fenfible drunkennefs.” ' "v
In the fpring feafon malignant fevers prevail in this
country; concerning which our author mentions no re¬
markable particular, but that eggs are a kind of poi-
fon, and that bleeding is very prejudicial. He re¬
commends a vegetable diet, and the bark in very large
quantity. > i6r
Notwithflanding the oppreflion which the Egyptians Commerce
labour under, a very conliderable trade is carried on Cairo
from Cairo. This flourishing ftate of commerce in^^er‘’
the midit of the molt defpcrate barbarity and defpotifm
is owing to three caufes. 1. That all the commodities
confumed in Egypt are collected within the walls of
that city. 2. That the Mamlouks and all the people
of property reflde in that place, and there fpend their
whole revenues. 3. By the fituation of this city it is
a centre of circulation *, correfponding with Arabia
and India, by the Red Sea j with Abyflinia and the in¬
terior parts of Africa, by the Nile j and with Europe
and the Turkilh empire, by means of the Mediterra¬
nean. A caravan comes here annually from Abyflinia,
bringing from xooo to 1200 Haves, with gum, ivory,
gold-dull, oftrich-feathers, parrots, and monkeys.—
Another, which fets out from the extreme parts of Mo¬
rocco, takes in pilgrims for Mecca from all that
country as far fouth as the mouth of the river Senegal.
It conlilts of not fewer than three or four thoufand ca¬
mels , and, pafling along the coalts of the Mediterra¬
nean, collects likewife the pilgrims from Algiers, Tri¬
poli, and Tunis, arriving at lalt at Alexandria by the
wray of the defert. Proceeding thence to Cairo, it joins
the Egyptian caravan 5 and then, fetting out both toge¬
ther, they take their journey to Mecca, from whence they
return in one hundred days j but the Morocco pilgrims,
who have Hill 6oo leagues to go, are upwards of a year
in returning. The commodities they bring along with
them are, India fluffs, ftiawls, gums, perfumes, pearls,..
and principally coffee. Belides the profits of this mer-
chandife, conliderable fums arife from the duties paid
by pilgrims, and the fums expended by them.
The caravans above-mentioned are not the only
means by which thefe commodities are brought to
Cairo. They arrive alfo at Suez, to which port the
foutherly winds bring in the month of May fix or eight
and twenty fail of veffels from Jedda. Small caravans
likewife arrive from time to time from Damafcus with
filk and cotton fluffs, oils, and dried fruits. During
the proper feafon there are alfo a number of veffels in
the road of Damietta, unloading hogfheads of tobacco
from Latakia, vaft quantities of which are confumed
in this country. For this commodity riee is taken in
exchange j while other veffels bring clothing, arms,
furs, paffengers, and wrought filk, from Conftantinople.
There are other veffels which come from Marfeilles,
Leghorn, and Venice, with cloths, cochineal, Lyons
fluffs and laces, grocery ware, paper, iron, lead, Ve¬
netian fequins, and German dahlers. Thefe are con¬
veyed to Rofetta in barks called by M. Volney djerm,
but which feem to be the fame mentioned by Mr Bruce
under the name of canja, and which are particularly de-Vefl'cls
feribed by him. He informs us, that there is a pecu-na*’
liarity in the form of this veffel wdiich makes it ufeful^^16, t^ie
for navigating the river Nile; and that is, that thefCj^e((e‘
keel
E G Y [6
, ^gyp*- keel is not ftraight, but a portion of a parabola, whofe
v ' curve is almoft infenfibie to the eye. Hence, as fand-
banks are very common in the Nile, and veffels are apt
to ftrike them when the water becomes low, the middle
of the canja will be aground while the extremities are
aRoat, and thus by means of oars and other afiiftance,
it is always poflible to get clear j but were the keel
llraight, this would be altogether impoflible, by reafon
of the vail fails thofe veffeis carry, which would urge
them on with too much force to be recovered. The
accommodation on board thefe veffels is much better
than what could be expe&cd i but they are liable to
the depredations of robbers, who either fwim under
water in the day-time, or upon goats fkins during the
night : though thefe feldom attack any boats where
there are Europeans, whom they dread on account of
their fkill in lire arms.
From fo many fources we need not wonder that the
commerce of Cairo Ihould be in a very flourilhing Hate.
In 1783, according to the report of the commiifioner-
general of the cuiloms, it amounted to no lefs than
6,250,000!.; but notwithflanding this Ihow of wealth,
the trade carrifed on at Cairo contributes very little to
the enriching of the people. This will readily appear,
when we confider, that great part of the coffee and
other merchandife brought from India is exported to
foreign countries, the value being paid in goods from
Turkey and other European countries 5 while the
country confumption Conliils entirely, or mollly, in
articles of luxury already finilhed, and the produce gi-
ven in return is mollly in raw materials,
through'the Schemes have frequently been projfefted of enlarging
ifthmus of e commerce °f Egypt by cutting through the iith-
Suez. mus of Suez, and thus joining the Mediterranean and
■Red feas by a canal. This is looked upon by M.
Vclney as impradlicable. He owns, indeed, that no
objedliofi can arife from the dillance, w'hich is not
•more than 18 or 19 leagues j neither does any ob-
ilacle arife from mountains, or the inequality of levels,
the whole being a fandy barren plain. The difficulty,
which he conhders as infuperable, proceeds from the
nature of the correfponding coalls of the Mediterra¬
nean and Red feas $ both of which are low and fandy,
wdiere the waters form lakes, Ihoals, and moralfes, fo
that Ihips cannot come within a confiderable dillance
of either j and it wTould be fcarce poffible to cut a per¬
manent canal amidll thefe fnifting fands : not to men¬
tion, that the Ihore is deftitute of harbours, which mull
be entirely the work of art. The country, befides has
not a drop of frefh water, which it would therefore be
neceffary to bring as far as from the Nile. The bell me¬
thod of effecling this jundlion, therefore, is by means of
t3ie river itfelf; and for this the ground is perfedlly
well calculated. This has been already done by feveral
Egyptian princes, particularly Sefollris ; and the canal
is faid to have been 1 70 feet wide, and deep enough for
large veflels. After the Grecian conquefl it w7as renewed
by the Ptolemies, then by Trajan, and lallly by the
Arabs. Part of it Hill remains, running from Cairo
to the north-eall of the Berket-el-Hadj^ or Lake of the
Pilgrims, where it lofes itfelf. At prefent the com¬
merce with Suez is only carried on by means of cara¬
vans, which fet out towards the end of April or begin¬
ning of May, or in the months of July and Augult j
waiting the arrival of the veffels, and fetting out on
2.
32 ] E G Y
their departure. The caravans are very numerous; that Egypt.
with which M. Volney travelled conliiting of 5000 or 1 
6000 men and 3000 camels. The country is as defert
and barren as poflible, without a Angle tree or the
fmallell fpot of verdure } fo that every neceffary for
thofe who accompany the caravan mull be carried
on the backs of the camels, wood and water not ex¬
cepted.
The cullom-houfes of Egypt are in the hands of the
Chriltians of Syria. Formerly they were managed by
Jews j but thefe were completely ruined by the extor¬
tions of Ali Bey in 1769. The Syrian Chrillians came
from Damafcus fomewhat more than 50 years ago j and
having by their economy and induftry gained poffeflion
of the moll important branches of commerce, they wrere
at length enabled to farm the cullom-houfes, which is
an office of great confequence. There were at Aril only
three or four families of them ; but their number has
flnce increafed to more than 500, and they are reckon¬
ed very opulent, ^
From what has already been faid concerning theLowftate
Hate of the Egyptians, wre may naturally conclude, of the ait;
that the arts and all kinds of learning are at a very low _an^ learn-
ebb among them. Even the moil Ample of the mecha-*n®°
nical profeflions are Hill in a Hate of infancy. The
work of their cabinet-makers, gun-fmiths, and lock-
fmiths, is extremely clumfy. There are manufactures
of gunpowrder and fugar •, but the quality of both is
very indifferent. The only thing in w hich they can be
faid to arrive at any degree of perfection is the manu¬
facture of Aik fluffs; though even thefe are far lefs
highly flnifhed than thofe of Europe, and likewdfe bear
a much higher price. One very extraordinary art in¬
deed is Hill extant among the Egyptians, and appears
to have exifled in that country from the molt remote
antiquity j and that is a power of enchanting the mofl
deadly ferpents in fuch a manner, that they (hall allow
tbemfelves to be handled, nay even hurt in the fevereff
manner, wathout offering to bite the perfon who injures
them. Thofe who have this art are named Psylli $
to which article we refer for an account of what has
been faid on the fubjeCt by ancient and modem tra-
veHers, . _ 1<f£
The long and bloody war to which the revolution of War in
France gave rife, induced the government of that coun- Egypt,
try to leave no meafure unattempted, by which the
grandeur, independence, and commerce of Great Bri¬
tain might be as much injured as poffible, if not utter¬
ly dellroyed. The conquefl of Egypt was therefore
projeCled, as a preparatory Hep towards the fubjugation
of the Eaft Indies, to be effeCted by reaching the In¬
dian ocean through the ifthmus of Suez. This was a
daring, a defperate undertakings and no military char¬
acter of which France could boaft, was conAdered as
equal to its fuccefsful execution but the hero of Maren¬
go. He accordingly embarked at Toulon, as com-
tnander in chief of the army of the eaft, which a-
mounted to about 40,000 men, and having compelled
Malta to furrender in the courfe of his voyage, he fleer- I(56
ed for the coaft of Egypt, and arriving at Alexandria Alexandria
on the ill of July 1798, he carried it by affault on taken by
the evening of the 5th. ff'e French.
It is wTell known that while Bonaparte continued in
Italy, he ftridly prohibited his troops from committing
aCls of rapine and plunder, of which, however, they
were
Egypt-
167
Battle of
%h« Nile.
E G Y [
tverfe guilty at Alexandria, and confctjUently it is to be
' nrefumed that the commander in chief could not then
prevent it. If he could, he was unqueftionably blind
to his own intereft not to do fo, fince nothing was more
Unlikely to conciliate the a flections ot the Egyptians.
Cairo next furrendered to the viftors on the 23d of the
fame month. The French general attacked one of the
enemy’s pods at Lambabe on the 25th, when 300 of the
enemy were killed ; but this was only a prelude to the
memorable battle of the pyramids, which was fought
on the following day, and ieemed for the prefent to de¬
cide the fate of Egypt. The Mamlouks loft 2000
men 5 and 400 camels, together with their baggage and
50 pieces of cannon, fell into the hands of the conquer¬
ors. Thus far Bonaparte appeared to be the favourite
of fortune, by whom he was never t<3 be deferted •, but
he foon found that the race is not always to the iwift,
or the battle to the ftrong. He experienced a reverfe
of an irreparable nature 5 and as it does not appear that
he entertained the fmalleft apprehenfion of it, it gave a
trait of ferocity to his fubfequent conduit which he had
never before exhibited.
Admiral Nelfon appeared off the mouth of the Nile
on the 1 ft of Auguft, with a naval force equal to that
of the French admiral, and although the fleet of the
latter was fo ftationed and defended as to render an at¬
tack extremely hazardous, the Britifh hero was determin¬
ed to attempt it 5 and in this he fucceeded to the utmoft
of his wilhes. He captured nine fail of the line belonging
to the enemy, L’Orient, the admiral’s flag fliip of 1 20
guns, having blown up during the defperate and bloody
engagement. The lofs on the part of the French muft
have been immenfe, fince GantheaUme mentions 3100
made prifoners, whom the Britifti commander returned:
of this number there were 800 wounded. J he Bri-
fcilh had about 20 2 killed, belides fixteen officers, and
678 wounded.
After Grand Cairo furrendered to the French, Bona¬
parte formed his victorious army into three divifions,
one of which was commanded by General Defaix,
whofe deftination was Upper Egypt, in purfuit of the
flying Mamlouks j the fecond divifion he left for the
defence of Cairo, and marched in perfon at the head
of the third in purfuit of Ibrahim Bey, who had taken
his route towards Syria with a rich caravan. To ren¬
der abortive, if poflible, the defigns of Bonaparte, Bri¬
tain formed an alliance with the Sublime Porte, and the
chief preparations for Carrying the concerted plan into
effeft, were made in Syria, under the care and direc¬
tion of the pacha Djezzar. The frontiers of Egypt to¬
wards Syria were to be attacked by an army from Alia
Minor, the operations of wffiich wrere to be favoured by
making a ftrong diverfion towards the mouths of the
Nile, and by various affaults in Upper Egypt with the
^remains of Mourad Bey’s army. Sir Sidney Smith left
Portfmouth to fuperintend the execution of this exten-
five plan, and grant every affiftance in his power by
the maritime force under his command.
In the mean time care was taken to block up the
harbour of Alexandria with four fail of the line and
five frigates, under the command of Commodore Hood,
as he found it impracticable to burn or deftroy the
French fleet of tranfports, without the affiftance of a
land force fufficient to attack Alexandria. Of the light
Veffels which had been fent him by the combined fleet
Vol. VII. Part II,
Egypt-
168
633 1 E G Y
of Turks and Ruffians the commodore had made no
ufe ; and he alfo found the report to be without, foun¬
dation, that the veffels in the old. port belonging to
the French, were burnt. It was in order to deftroy
the preparations of the pacha Djezzar, and difconcert
the plans of Sir Sidney Smith, that General. Bonaparte
thought of leaving Egypt and marching into Syria.
The refult of this expedition, as w^e have already hint¬
ed, was fatal to the French intereft, although Bona¬
parte perhaps never undertook an enterprife with more
rational expectations of ultimate fuccefs.
The town of Jafta, (anciently Joppa), was obftinate-
ly defended, but at laft furrendered to the fuperior tac¬
tics of European foldiers. From this place the Irench
general marched with his army in three divifions againft
St Jean d’Acre, which put an effeaual period to his
hitherto triumphant Career. Ihe pacha wras powerml-^
ly encouraged by Sir Sidney Smith to make an obfti- Smith,
nate refiftance to the attack of Bonaparte ; and to ani¬
mate him ftill more with the hopes of being able to
hold out, and force the affailants in the iffue to raife
the fiege, he fent him a French engineer of diftinguiffi-
ed merit, by whofe inftrumentality Sir Sidney Smith
had been enabled to effeCt his efcape from prifon.
Although the fortrefs was completely repaired by
Colonel Philipeaux (the name of the engineer),
yet it is more than ^probable that it could not have
long held out againft the {kill and intrepidity of
Bonaparte, if his heavy artillery had not been inter¬
cepted by the Britilh on their way from Damietta and
Rofetta. ' After a defperate and bloody fiege of about
61 days continuance, the French commander was ob¬
liged to abandon the hope of making Acre furrender. ^
In the courfe of his retreat back again to Egypt,- Bona¬
parte’s army ravaged the whole country, burnt the har-
vefts, deftroyed the defences of the difterent ports, the
the magazines, and every refource of which the lurks
might have availed themfelves in approaching the fron¬
tiers of Egypt. He reached Grand Cairo in 26 days
after raifing the fiege of Acre.
Sir Sidney Smith, with indefatigable zeal and attivi-
ty, continued to execute the remaining parts of the
plan of operations againft Egypt, which was feconded
by the increafing zeal of the Turks in the profecution
of the fame defign. The troops deftined to make an
attack upon Alexandria were affembled in the different
ports in the ifland of Rhodes, by Seid Muftapha Pacha,
the enterprife being conducted by European officers.
The combined fleet of Turkey and Britain only, waited
the arrival of a convoy, previous to their failing for
Egypt, which the captain pacha, who then lay at an¬
chor in the Dardanelles, was to defpatch to Rhodes.
During the abfence of General Bonaparte, no method had
been left unattempted, in order to ruin the intereft of
the French, and kindle a fpirit of rebellion in the minds
of the people. This plan fucceeded to a certain extent,
but the prefence of Bonaparte reftored tranquillity.
His army no doubt ftiffered feverely in its march to Sy¬
ria ; but with fuch zeal, and activity did he turn his at¬
tention to the re-eftablilhment of its organization, that
it was in a condition to undertake active operations in
the ftiort period of three weeks, although, according to
very high authority, it had been completely buried in
the burning fands of the defert.
While Bonaparte was in the vicinity of the pyra- ^
4 L mids,
'^gypt
169
Bonaparte
returns to
France.
E G Y [ 63
mids, intended to purfue Mourad Bey in Ids retreat to
iaj'Oum, he received intelligence from Alexandria, that
n lurkiih fleet of 100 fail had come to anchor in the
bay of Aboukir, from which 3000 troops had landed
on the fliore of the peninfula, and carried the fort of
Aboiiltir by affault. He accordingly gave directions
to his officers to march their forces towards the place
ot landing, and the firff; rendezvous of the army was
appointed to be at Rhamanieh, fituated on the left
iide of the Nile. The advanced guard under the
command of General Murat, took the route to
Gizeh, and General Menou’s moveable column, to¬
gether with the park of artillery and the llaff,’for¬
med a junaion at Rhamanieh on the 20th of July.
After the French army quitted its poll at the vil¬
lage of Birket, it afl'embled at the wells between
Alexandria and Aboukir; and Bonaparte fixed his
head quarters at the former place.
Ihe lurkiih army was about 15,000 flrong, and
receiving d.any reinforcements. When Bonaparte came
in fight of it, he inftantly formed his columns to attack
it, and General d’Ellaing carried the entrenched height
of the enemy, by which their right was fupported, at
the point of the bayonet. I heir two wings were cut
oft from retreating by General Murat, who marched
up to the centre of the enemy with a body of cavalry.
By this manoeuvre 2000 men ^eriffied by water, or
were killed by the fire of the republicans. As Bona¬
parte found that the chief ftrength of the Turkiih ar¬
my was at the centre, he changed his pofition as the
nature of the ground rendered it neceftary. By a variety
of experienced movements, in which the French loft
feveral brave officers, the Turks were at length thrown
into the utmoft confufion, retreated" in every direction
and threw themlelves into the fea. The majority of
them were at too great a diftance from the veffels, to
he. laved in this manner from a watery grave. After
this battle, the fort of Aboukir was fummoned to fur-
render, which was defended with the moll defperate
lury, as the Turks had no idea of capitulating with
arms in their hands. General Menou conduced the
liege with great vigour and addrefs, and after bombard¬
ing it for eight days, till it exhibited nothing but a
heap of ruins, the fon of the pacha and 2000 men laid
down their arms, and were made prifoners of war. In
the fort the republicans found 1800 men killed, and
300 wounded. It is faid that Sir Sidney Smith wit-
neffed this melancholy reverfe of fortune on the part of
the Turks, without having it in his power, as at Acre
to grant them relief, or to animate them by his coura¬
geous example.
The next day Bonaparte returned to Alexandria, where
he learned the difmal fituation of French affairs on the con¬
tinent of .Europe, particularly in Italy and on the Rhine,
and the violent commotions which were agitating the in¬
terior of France. This determined him to quit Egypt,
and return to his own country, full of the idea of vert¬
ing in his own perfon.the fovereign authority, to which
he has at length attained, both in name and reality.
General Berthier alone was his confidential friend, to
whom he communicated his future defigns. Admiral
Gantheaume was ordered to get ready two frigates with
the utmoft expedition, without informing that officer
>vhat was to be their deftination, and brought with him
4 ] E G Y
Generals Lafnes, Marmont, Murat, and Andreoffi, to¬
gether w.th Monge. and Berthollet of the inftitute •1
-Beiheres and his guides received fealed notes which
were not to be opened till a certain day, and certain
hour and at a particular point of the fea-ffiore. They
were found to contain orders for immediate embarka¬
tion ; and. another packet which was to be opened on
the day alter the failing of the frigates, contained the
nommatmn of General Richer to the chief command,
and Deiaix to that of Upper Egypt.
By difpatches from General Richer fubfequent to the
departure of Bonaparte, it appears that Mourad Bev
havingdropt down the Nile to El-Ganayur, was repul-
fed by a divihon of the army of Upper Egypt, Jder
the command of General Morand. Being overtaken
m his flight by this divifion, his camp was furprifed at
oamahout, a vaft number of Mamlouks were entirely
cut off; 200 camels with fpoils, 100 horfes, and a pro¬
digious quantity of. military implements fell into the
hands of the republicans, and it was with the utmoft
difficulty that the bey effeaed his efcape. Thus fm
nally defeated, Mourad wandered through the inhofpt
table deferts of Upper Egypt, in fearch of an afylum
and. the means of fubfiftence. As this man was fuch
an indefatigable enemy to the French, Defaix refolved
to exterminate him if poffible, and for this purpofe two
columns of infantry mounted on dromedaries were im¬
mediately organized, the one commanded by Defaix
m perfon, and the other by Adjutant-general Boyer
who came up with Mourad on the 19th of Qdober in
the defert of Sediman, after a forced march of three
days.. The Mamlouks fought with determined valour
and intrepidity, animated with the hopes of gaining
poffeffion of the dromedaries. Their attack was met
with fuch vigour on the part of the republicans, that
the Mamlouks and Arabs were foon put to flight, and
purfued back to the deferts by their intrepid conquer-
On the 24th of September, a Turkiffi fleet of 18
veffels came to anchor before Damietta, which was fo
rapidly increafed by conftant reinforcements, that it
amounted to 53 about the end of the fubfequent month.
Ihe naval commander of this fleet was Sir Sidney
Smith on board the Tyger.. On the ill of November
4000 I urks eftedled a landing, who were attacked by
General Verdier at the head of 1000 men, and loft, in
this apparently unequal conteft, no fewer than 3000
men killed, 800 prifoners, including Ifmael Bey, the
fecond in command, 32 Hand of colours, and five pieces
of cannon.. After a number of fubfequent battles and
inferior Ikirmifties which the republicans fought with
vaiious fuccefs, they feemed willing to evacuate Egypt
upon certain.conditions, which met with the approba¬
tion of Sir Sidney Smith ; but they were afterwards re-
jedfted by a fpecies of policy for which it is difficult toi
account, and frefh obftacles were thrown in the way of
the propofed evacuation. I his was an event much to
be defired by the republicans, according to the opinion
of feme, while the French denied that the neceflity of
fuch a meafure ever exifted. According to them, they
had Hill 20,000 effedlive men in that quarter of the
globe, and liberally ftiared in the affedlions of the inha¬
bitants, by whom they wrere aflifted.
The gallant mid experienced Kleber, who fucceeded
Bonaparte
E G Y [ 635 ] E 0 Y
170
Affaffina-
tion of
Kiebsr.
,Egypt. Bonaparte in tlie chief command of the army of the
Eaf, was treacheroufly affaflinated by a janiiTary, while
prefenting the general with a memorial for his perufal,
on which the chief command devolved on Menou, but
not till fome other generals, and Reynier in particular,
had refufed to accept of it. Sufpicions fell heavily on
General Menou, who, it was fuppofed, had hired the af-
faffm, as it was well known that a variance fubfiited be¬
tween Kleber and Menou but it is only doing juftice
to the latter to declare, that the dying affertions of the
murderer fufficiently evinced the contrary; He was
mod probably hired by the grand vizier himfelf j but
who advifed the vizier to the adoption of fuch an in¬
famous, cowardly meafure, we mud leave to our readers
to find out. The affadin was impaled alive, his right
hand burnt off, and his body left to be devoured by
birds of prey. Three Iheiks who were privy to his de-
figns, but did not divulge them, were beheaded.
Lieutenant Wright was difpatched to Cairo by Sir
Sidney Smith, with propofitions refpefting the evacua¬
tion of Egypt to General Menou, whofe anfwer the'
combined powers expecled with anxiety, as the grand
vizier was determined to advance againd the enemy at
the head of 30,000 men, Ihould Menou evince himfelf
determined not to evacuate Egypt. He foon gave
them to underdand that no overtures of accommodation
which they could make to him would be received;
He apcordingly recommenced hodilities, and marched
againd Syria with the principal part of his army 5 a mea¬
fure which proved abortive under the aufpices of Bona¬
parte, by the prompt and gallant exertions of Sir Sid¬
ney Smith. The determination of Menou in fuch a
perilous fituation, was no doubt owing in a great mea¬
fure to the acceffions of drength which he received from
the different beys who joined him, as the bed means of
fecuring their independence, having been informed that
the Sublime Porte was determined on the conqued of
Egypt, and the deitruflion of the Mamlouks. The
aid of Mourad Bey was of fome importance to Menou,
and it formed a junction of a very Angular nature, ha¬
ving formerly been fuch a determined enemy of the
French. Menou drongly fortified Alexandria, Da-
mietta, and Rofetta, and not only finilhed the lines
Which Colonel Bromley had begun at Aboukir, but
made to thefe feveral important additions, putting every
place into fuch a date of defence as feemed to bid de¬
fiance to any attack from the Turks.
In the mean time Britain was not idle, but aiflive in
the organization of an army dellined to invade Egypt,
and compel the French troops to evacuate that country,
which was too contiguous to her inedimable polTedions
in the Ead Indies $ and the command of it was given to
that gallant and highly refpeftable officer, the late ge¬
neral Sir Ralph Abercromby, who appeared off" Abou¬
kir in the beginning of March, 1801. The weather
proving unfavourable for fome days, Sir Ralph did not
begin to land his troops till the 8th, at an early hour
in the morning. The French having marched from
The Brnilh Alexandria, took their dation on the heights of Abou-
_ kir, to prevent the landing of the Britilh forces. An
action foon commenced between the holtile armies,
which laded for two hours, but the republicans were
obliged to retreat, having only 4000 men to oppofe to
three times that number. The lofs of the French on
this occafion was edimated at 30QO, and that of the
j7i
under
Abercrom
by vidlori-
ous at A-
boukin
Britiffi about 1500 men, in killed, wounded, and pri- Egvpt
foners. El ^ 1
After this, few actions of importance occurred till
the memorable 2id of March, on which day a battle
was fought about four miles from Alexandria. A falfei
attack on the left of the Britiffi army was the com¬
mencement of hodilities, but the French were dill more
anxious to turn the right of their opponents, which they
attempted in vaim With the fame fuccefs they made
an attack upon the central divifion. About 200 pri-
foners fell into the hands of the Britiffi, but as their
cavalry was much inferior to that of the enemy, whofe
retreat was alfo covered by cannon on the oppofite
hills, they could not purfue their advantages. The lofs
of the Britilh at this time was very confiderable, but
the mod irreparable part of it was the lofs of the com¬
mander in chief, who was mortally wounded on the
2111, and died on the 28th of the fame month. He
was fucceeded by General Hutchinfon, the fecond in
command, to whom was committed the completion of
the plans which his worthy predeceffor had concerted.
He attacked the French on the 19th of May, near
Rhamanieh, and forced them to retire towards Cairo.
He had 4000 Britiffi troops under his command, and
an equal number of Turks under the captain pacha.
He then direiled his route towards Cairo, from which
the army of the grand vizier was didant only four
leagues, in a north-ead direction. A ifeinforcement
of 300b Britiffi troops reached Aboukir about the 6th
of May,
By the advice of Colonel Murray and fome other
Britiffi officers then in the camp of the grand vizier,
his highnefs obtained a viftory over 4600 French,
with 9000 chofen troops, not encumbered with the
women and ufelefs attendants fo commonly met with
in the camps of eallern generals. The whole of
Damietta foon fell into the hands of the allies, and the
fucceflor of Mourad Bey declared in favour of the Bri¬
tiffi, joining Sir J. Hutchinfon with 150b cavalry, that
kind of force of which the Britilh commander dood in
greated need. In a ffiort time after, the French eva¬
cuated Cairo, which was taken poffeffion of by the
combined Turkiffi and Britilh army. The republicans
■were not made prifoners, but were, by dipulation, to
be conveyed to the neared ports belonging to France,
at the expence of Great Britain. Alexandria dill held
out, which Menou was determined to defend to ^the
lad, notvvithdanding the idea of receiving reinforce¬
ments appeared altogether groundlefs. He was at
length, however, obliged to furrender, and thus the
whole of Egypt was in poffeffion of the allies. As the
joyful news of peace between Great Britain and France
had fpread over the country prior to this intelligence,
it did not excite half the intered in the mind of Bri¬
tons which it would otherwife have done,
For a defcription of thofe dupendous and almod in-
dellruclible monuments of human grandeur, the pyra¬
mids, fo often taken notice of and defcribed by travel¬
lers, fee the article Pyramids.
EGYPTIANS, or Gypsies. See Gypsies.
EHRE 1.1 A, a genus of plants belonging to the pen-
tandria clafs. See Botany Index.
EH RH ART A, a genus of plants belonging to the'
hexandria clafs. See Botany Index.
EHUD, the fon of Gera, a Benjamite, a man left-
4 L 2 handed,
E J E [ 636 ] E K R
£Ia hantled, who delivered Ifrael from the oppreflion of
. H Eglon king of Moad, under whom they ferved for 18
10n', years. See Eglon. It being cuftomary for the If-
raelites to fend a prefent or tribute to the king of
Moab ; in the year of the world 2579, being the laft
year of their fervitude, Ehud was appointed to carry
it, who having a defign either to free his country from
this oppreffion, or perilh in the attempt, had for this
purpofe provided himfelf with a dagger which had two
edges, and which he had concealed on his right fide,
(Judges iii. 15. &c.). After he had delivered the pre¬
fent, pretending he had fomething of great importance
to communicate to the king, he obtained a 'private au¬
dience of him 5 when taking his opportunity, he dab¬
bed him with the- poniard to the heart, and fo (hut¬
ting the door after him, had time to make his efcape 5
for as the king was a very corpulent man, his atten¬
dants fuppofed that he was either repoflng or eafing
himfelf, and therefore forbore to enter his apartment
until Ehud was quite gone. As foon as he came to
Mount Ephraim, he gathered together the Ifraelites
that lay neareft him, acquainted them with what he had
done ; and then fecuring the fords of Jordan that none
of them might efcape, he fell upon the Moabites, and
fubdued them.
EIA, or Ey, in our old writers, is ufed for an
iiland. Hence the names of places ending in ez/, de¬
note them to be iHands. Thus, Ramfey, the ille' of
rams -y Shepey, the ille of fheep, &c.
Eia is alfo fometimes ufed for water 5 and hence the
names of places near waters or lakes terminate in ey.
EJACULATOR, in Anatomy, a name applied to
two mufcles of the penis, from their office in the ejec¬
tion of the feed. See Anatomy, Table of the Mufcles.
EICETyE, called alfo Heicetye and Hicet^e, here¬
tics of the feventh century, who made profeffion of the
monadic life.—From that paffage in Exodus where
Mofes and the children of Ifrael are faid to have fung
a long in praife of the Lord, after they had palled the
Red lea, wherein their enemies had periffied ; the ei-
cetae concluded, that they mull ling and dance to praife
God aright: and as Mary the prophetefs, lifter of
Mofes and Aaron, took a drum in her hand, on the
fame occalion, and all the women did the like, to
teftify their joy, by playing, beating, and dancing $
the eicetae, the better to imitate their conduct herein,
endeavoured to draw women to them to make profeffion
of the monaftic life, and affift in their mirth.
EICK. See Bruges.
EIDER-duck. See Anas, Ornitholggy Index.
EiDF.R-Down, the down of the ‘eider-duck. The
eider-duck plucks off the down from its breaft for the
purpofe of making its neft, which, after being robbed
by thofe who collefl the down, is renewed by the bird
till its breaft is quite bare.
EJECTA, a term ufed by lawyer for a woman de¬
flowered or call from the virtuous.
EJECTION, in the animal economy, the evacua¬
tion, or difcharging any thing through fome of the e-
mundlories, as by ftool, vomit, &c.
Ejection, in Scots Law, is the turning out the pof-
feffor of any heritable fubjecl by force 5 and is either
legal or illegal. Legal ejection is where a perfon ha¬
ving no title to poffefs, is turned out by the authority
of law. Illegal ejection is one perfon’s violently turn¬
ing another out of poffeffion without lawful autho-Ejeflment^
rity. Ekron.
EJECTMENT, in Englifh Law, a writ or action ’ v ^
which lies for the leffee for years, on his being ejected
or put out of his land, before the expiration of his term,
either by the leflbr or a ftranger. It may alfo be
brought by the leffor againft the leffee, for rent in ar¬
rears, or holding over his term, &c. Eje£hnent of
late years is become an aftion in the place of many real
a&ions, as writs of right, formedons, &c. which are
very difficult, as well as tedious and expenlive j and this
is now the common adtion for trial of titles, and reco¬
vering of lands, &c. illegally held from the right own¬
er ; yet where entry is taken away by difcents, fines,
recoveries, diffeifins, &c. an ejedment lhall not be
brought 5 whereby we find that all titles cannot be
tried by this adion.
The method of proceeding in the adion of ejedment
is to draw up a declaration, and feign therein a leafe
for three, five, or feven years, to him that would try
the title ; and alfo feign a cafual ejedor or defendant 5
and then deliver the declaration to the ejedor, who
ferves a copy of it on the tenant in poffeffion, and gives
notice at the bottom for him to appear and defend his
title j or that he the feigned defendant wall fuffer
judgment by default, whereby the true tenant will be
turned out of poffeffion : to this declaration the tenant
is to appear at the beginning of next term by his attor¬
ney, and confent to a rule to be made defendant, in-
ftead of the cafual ejedor, and take upon him the de¬
fence, in which he muft confefs leafe, judgment, entry,
and aufter, and at the trial ftand upon the title only :
kut in cafe the tenant in poffeffion does not appear,
and enter into the faid rule in time, after the declara¬
tion ferved, then, on affidavit being made of the fervice
of the declaration, with the notice to appear as afore-
faid, the court will order judgment to be entered againft:
the cafual ejedor by default; and thereupon the te¬
nant in poffeffion, by writ habere facias pqffeffionem, is
turned out of his poffeffion. On the trial in ejed¬
ment, the plaintiff’s title is to be fet forth from the
perfon laft feifed in fee of the lands in queftion, under
whom the leffor claims down to the plaintiff, proving
the deeds, &c. and the plaintiff lhall recover only ac¬
cording to the right wffiich he has at the time of bring¬
ing his adion. And here, another who hath title to
the land, upon a motion made for that purpofe, may
be defendant in the adion with the tenant in poffeffion,
to defend his title j for the poffeffion of the lands is
primarily in queftion, and to be recovered, which con¬
cerns the tenant, and the title thereto is tried collate¬
rally, wffiich may concern fome other.
EKRON, a city and government of the Philiftines^
It fell by lot to the tribe of Judah, in the firft divifion
made by Joffiua (xv. 45.), but afterwards it was given
to the tribe of Dan (id. xix. 43.). It was fituated
very near the Mediterranean, between Alhdod and Jam-
nia. Ekron wras a powerful city, and it does not ap¬
pear by hiftory that the Jewrs w^ere ever foie peaceable
poffeffors of it : the Ekronites w'ere the firft who faid
that it wras neceffary to fend back the ark of the God
of Ifrael, in order to be delivered from thofe calamities
wffiich the prefence of it brought upon their country,
(1 Sam. v. 10.). The idol Baalzebub was principally
adored at Ekron (2 Kings, i. 2. &c.)
ELA1AGNUS,
Ebeagnus
If .
Elafmis.
See
E L A r
ELxEAGNUS, Oleaster, or Wild Olive:
genus of plants, belonging to the tetrandna clals.
, Botany Index. . , ^ ,
ELiHOCARPUS, a genus of plants bexongmg to
the polyandria clafs. See Botany Index.
EL^EOTHESIUM, in antiquity, the anointing
room, or place where thofe who were to wreftle or had
bathed anointed themfelves. See Gymnasium.
ELAIS, a genus of plants belonging to the natuial
order of Pa/nue. See Botany Index.
ELAM, in Ancient Geography, a country frequently
mentioned in Scripture, and lying to the fouth-eah ot
Shinar. In the time of Daniel (via. 2.), Sufiana leems
to have been part of it} and before the capUvity, it
does not appear that the Jews called Perfia by any
other name. Elymse and Elymais are often mentioned
bv the ancients. Ptolemy, though he makes Elymais
a province of Media, yet he places the Elym* m Su¬
fiana, near the fea-coait. Stephanus takes it to be a
part of Affyria *, but Pliny and Jofephus more properly
of Perfia, whole inhabitants this latter tells us Iprang
from the Elamites. The beft commentators agree,
that the Elamites, who were the anceftors ot' the Per¬
sians, were defcended from Elam the fon of Shem. t
is likewife allowed, that the molt ancient among the
infpired writers conftantly intend Perlia, when they
fpeak of Elam and the kingdom of Elam. _ Thus, not
to detain the reader with unneceffary quotations, when
the prophet Jeremiah (xlix. 39.)> after denouncing
manv judgments againil this country, adds tneie words,
“ But it fhall come to pafs in the latter days, tnat I
will bring again the captivity of Elam, faith t e
Lord,” he is always understood to mean the reitera¬
tion of the kingdom of the Perfians by Cyrus, who
fubdued the Babylonians, as they before had fubdued
the Perlians.
ELAPHEBOLIA, in Grecian antiquity, a feltiyal
in honour of Diana the huntrefs. In the celebration
a cake was made in the form of a deer (s^os), and
olfered to the goddefs. It owed its institution to the
following circumftance : W hen the Phocians had been
feverely beaten by the Theffalians, they refolved, y
the perfuafion of one Deiphantus, to raife a pile of
combustible materials, and burn their wives, children,
and effeas, rather than fubmit to the enemy. This
refolution was unanimously approved by the women,
who decreed Deiphantus a crown for his magnanimity.
When every thing ivas prepared, before they fired the
pile, they engaged their enemies, and fought with fuch
defperate fury, that they totally routed them, and ob¬
tained a complete viaory. In commemoration of this
unexpeaed fuccefs, this festival was instituted to Diana,
and obferved with the greateft folemnity.
ELAPHEBOLIUM, in Grecian antiquity, the
ninth month of the Athenian year, anfwering to the
latter part of February and beginning of March. It
confiSled of 30 days ; and took its name from the
festival elaphebolia, kept in this month, in honour of
Diana the huntrefs, as mentioned in the preceding ar¬
ticle.
ELASMIS, in Natural Hijory, a genus ot talcs,
compofed of fmall plates in form of fpangles 5 and ei¬
ther Single, and not farther Affile •, or, if complex, on¬
ly ftffile to a certain degree, and that in fomewhat thick
laminae.—Of thefe talcs there are feveral varieties, fome
637 ] E L A
A with large fled others with fmall fpangles, which dii- ^
fer alfo in colour and other peculiarities.
ELASTIC, in Natural Philofophy, an appellation
given to all bodies endowed with the property of ela¬
sticity. See Elasticity.
Elastic Fluids. See Air, ELECTRICITY, GAS^and-
Elastic Vapours below.
Elastic Rejin. See Caoutchouc.
Elastic Vapours are fuch as may, by any external
mechanical force, be compreffed into a fmaller fpace
than what they originally occupied; restoring them¬
felves, when the preffure is taken off, to their former-
state with a force exactly proportioned to that with
which they were at firft compreffed. Of this kind are
all the aerial fluids without exception, and all kinds of
fumes raifed by means of heat whether from Solid or
fluid bodies.
Of thefe, fome retain their elasticity only when a
considerable degree of heat is applied to them or the
fubftance which produces them j while others remain
elaftic in every degree of cold, either natural or artifi¬
cial, that has yet been obferved. Of the former
kind are the vapours of water, fpirit of wine, mercu¬
ry, fal ammoniac, and all kinds of Sublimable falts 5 of
the latter, thofe of muriatic acid gas, hydrogen gas,
nitrous gas, common air, &c.
The elastic force with which any one of thefe fluids
is endowed has not yet been calculated, as being, ulti¬
mately greater than any obstacle we can put in its
way. Thus, if we comprefs the atmofpherical air, we
Shall find that for fome little time it will eafily yield to
the force we apply 5 but every fucceeding moment the
resistance wall become Stronger, and a greater and.great¬
er force mutt be applied in order to comprefs it far¬
ther. As the compreflion goes on, the veffel contain¬
ing the air becomes, hot j but no power whatever, has
Elaftic.
yet been able to destroy the elasticity of the contained
"fluid in any degree j for upon removing the prefiuie,
it is always found to occupy the very fame Space that
it did before. The cafe is the fame with aqueous
Steam, to which a fufficient heat is applied to keep it
from condenfing into water. This will yield to a cer¬
tain degree : but every moment the refiitance becomes
greater, until at laft it will overcome, any obstacles
whatever. An example of the power of this Kind of Steam
we have every day in the Steam engine j and the va¬
pours of other matters, both folid and fluid, have fre¬
quently manifested themfelves to be endowed with an
equal force. Thus the force of the vapours of fpirit
of wine has occasioned terrible accidents when the
worm has been Stopped, and the head of the Still ab-
furdly tied down to prevent an explofion y the vapours
of mercury have burft an iron box y and thofe of Sal
ammoniac, volatile falts, nitrous acid, marine acid,
phofphorus, &c. have all been known to burit the che¬
mical veffels which confined them with great force, in
fuch a manner as to endanger thofe who, Stood near
them. In Short, from innumerable obfervations, it
may be laid down as an undoubted fa£t, that there is
no Substance whatever capable of being reduced into, a
Slate of vapour, but what in that State is endowed with
an elaltic force ultimately fuperior to any obstacle we
can throw in its way.
It hath been a kind of defideratum among philo-
fophers to give a Satisfactory reafon for this altonilh •
ing
E L A [638
Vanmns lnS Pcwier of elafticity in vapour, fcemingly fo little ca-
1 t Pao 1 0 accompliiliing any great purpoie when in an
unconfined Hate. As air is that fluid in which, from
the many experiments made upon it by the air-pump
and otherwiie, the elaftic property has moil frequently
been obferved, the refearches of philofophers were at
firft principally diredted towards it. The caufes they
aliigned, however, were very inadequate j being found¬
ed upon an hypothefis concerning the form of the par¬
ticles of the atmofphere itfelf, which they fuppofed to
be either rolled up like the fprings of watches, or that
they confifted of a kind of elaftic flakes. This was
ollowed by another hypothefis concerning their fub-
ftance, which was imagined to be perfectly elaftic, and
fo ftrong that they could not be broken by any me¬
chanical power whatever 5 and thus they thought the
phenomenon of the elaflicity of the air might be ex¬
plained. But an infuperable difficulty ftill attended their
cheme, notwithftanding both thefe fuppofitions ; for
it was obferved, that the elaftic power of the air was
augmented not only in proportion to the quantity of
preffure it was made to endure, but in proportion to
the degree of heat applied to it at the time. Sir Ifaac
Newton was aware of this difficulty ; and juftly con¬
cluded, that the phenomena of the air’s elafticity could
not be folved on any other fuppofition but that of a
repulfive^ power dilfufed all around each of its parti-
c es, which became ftronger as they approached, and
weaker as thfey removed from each other. Hence the
common phenomena of the air-pump and condenfing-
engine received a latisfaffory explanation j but ftill it/
remained to account for the power Ihown in the pre¬
lent cafe by heat, as it could not be denied that this
element had a very great lhare in augmenting the ela¬
fticity of the. atmofphere, and feemed to be the only
•caule of elafticity in other vapours. It does not ap¬
pear that Sir Ifaac entered into this queftion, but con¬
tented himfelf with attributing to heat the property of
increafing repulfion, and afcribing this to another un¬
explored property called rarefaction. Thus matters
ftood till the great difcovery made by Dr Black, that
lome bodies have the power of abforbing in an un-
known manner the element in qtaeftion, and parting
'Vlt.h 11 afterwards, fo that it flows out of the body
which had ablorbed it with the very fame properties
t tat it had before abforption. Hence many pheno¬
mena of heat, vapour, and evaporation, w^ere explained
m a manner much more fatisfaftory than had ever been
attempted or even expeded before. One of thefe was
that remarkable property of metals becoming hot by
hammering 5 during which operation, in the Dodor’s
opinion, the element of heat is fqueezed out from be-
tween the particles of the metal, as water is from the
pore-; of a fponge by preffing it between the fingers.
Of the lame nature is the phenomenon above-mention¬
ed, that air when violently compreffed becomes hot,
by reafon of the quantity of more fubtle element
Iqueezed out from among the particles. In this man¬
ner it appeals that heat and the repulfive power of Sir
Ilaac Newton are the very fame j that by diminilhing
the heat of any quantity of air, its elafticity is effec¬
tually diminiffied, and it will of itfelf {brink into a
fmaller Ipace as effedually as by mechanical preffure.
In one cale wje have what may be called ocular d^*-
monftration of the truth of this dodrine, viz. that by
4
1
E L A
throwing the focus of a ftrong burning lens upon a
fmall quantity of charcoal in vacuo, the whole will be con¬
verted into inflammable air, having even a greater power '
of elafticity than common air in an equal degree of
heat. Here there is nothing elfe but heat or lioht
to produce the elaftic power, or caufe the particles'3 of
charcoal which before attracted now to repel each other.
In another cafe we have evidence equally ftrong, that
the element of heat by itfelf, without the prefence of
is capable of producing the' fame effed.
1 hus when a phial of ether is put into the receiver of
an air pump, and furrounded by a fmall veffel of water
the ether boils violently, and is diffipated in vapour!
while the water freezes, and is cooled to a great de¬
gree. I he diffipation of this vapour Ihows that it has
an elaftic force j and the abforption of the heat from
the water. {hows, that this element not only produces
the elafticity, but adually enters into the fubftance of
the vapour itfelf j fo that we have not the leaft reafon
to conclude that there is any other repulfive power by
which the particles are kept at a diftance from one
another than the fubftance of the heat itfelf. In
v hat. manner it ads, we cannot pretend exadly to
explain, without making hypothefes concerning the
form of the minute particles of matter, which muft al¬
ways be very uncertain. All known phenomena, how¬
ever, concur in rendering the theory juft now laid down
extremely probable. The elaftieity of the fteam of
u ater is exadly proportioned to the degree of heat
which flows into it from without; and if this be kept
up to a.iufhcient degree, there is no mechanical pref¬
fure which can reduce it into the ftate of water. This,
however, may very eafily be done by abftrading a cer!
tain portion of the latent heat it contains : when the
Elailio
Vapours.
elaftic vapour will become a denfe and heavy fluid.
1 he fame thing may be done in various ways wfith the
permanently elaftic fluids. Thus the pureft dephlo-
gifticated air,, when made to part with its latent heat
by burning with iron, is converted into a gravitating'
fubftance of an unknown nature, which adheres ftrong-
ly to the metal. If the decompofition is performed
by means of inflammable air, both together unite in¬
to. an heavy, aqueous, or acid fluid : if by mixture
with nitrous air, ftill the -heat is difcemible, though lefs
violent than in the twm former cafes. The decompofi¬
tion indeed is flower, but equally complete, and the
dephlogifticated air becomes part of the nitrous acid,
from which it may be again expelled by proper means :
but of thefe means heat muft always be one ; for thus
only the elafticity can be reftored, and the air be re¬
covered in its proper ftate. The fame thing takes
place in fixed air, and all other permanently elaftic
fluids capable of being abforbed by others. The con-
clufion therefore which we can only draw from what
data we have concerning the compolition of elaftic va¬
pours is, that all of them are formed of a terreftrial
fubftance, united with the element of heat m fuch a
manner that part of the latter may be fqueezed out from
among the terreftrial particles'; but in fuch a manner,
that as focn as the preffure is taken off, the furround¬
ing fluid rufhes in, and expands them to their original
bulk : and this expanfion or tendency to it will be in-
creafed in proportion to the degree of heat, juft as the
expanfion of a fponge wmuld be exceedingly augment¬
ed, if we could contrive to convey a ftream of water
into
>
E L A
Elafticity. into the heart of it, and make the'liquid flow out with
violence through every pore in the circumference. In
this cafe, it is evident that the water would a6t as a
power of repul/ton among the particles of the fponge, as
well as the fire does among the particles of the water,
charcoal, or whatever other fubftance is employed.
Thus far we may reafon from analogy; but in all
probability the internal and eflential texture of thefe
vapours will for ever remain unknown. Their ob¬
vious properties, as well as fome of their more latent
operations in many cafes, are treated of under Che¬
mistry.
It has been imagined by fome, that the artificial
elaftic fluids have not the fame mechanical property
with common air, viz. that of occupying a fpace in-
verfely proportional to the weights wuth vdiich they
are prefled : but this is found to be a miftake. All of
them likewife have been found to be non-condu£tors
of eledlricity, though probably not all in the fame de¬
gree. Even aqueous vapour, when intimately mingled
with any permanently elaftic fluid, refufes to conduct
this fluid, as is evident from the highly eleftrical ftate
of the atmofphere in very dry wreather, when we are
N certain that aqueous vapour muft abound very much,
and be intimately mixed wdth it. The colour of the
eleftric fpark, though it may be made vilible in all
kinds of permanently elaftic vapours, is very different
in different fluids. Thus in inflammable and alkaline
air it is red or purple, but in fixed air it appears
“White.
ELASTICITY, or Elastic Force, that property
of bodies wherewith they reftore themfelves to their
former figure, after any external preflure.
The caufe or principle of this important property
elafticity, or fpringinefs, is varioufly afligned. The
Cartefians account for it from the materia fubtilis ma¬
king an effort to pafs through pores that are too nar¬
row for it. Thus, fay they, in bending, or compref-
fing, a hard elaftic body, e. gr. a bowq its parts recede
from each other on the convex fide, and approach on
the concave : confequently the pores are contradled or
ftraitened on the concave fide 5 and if they were before
round, are now, for inftance, oval fo that the materia
fubtilis, or matter of the fecond element, endeavouring
to pafs out of thofe pores thus ftraitened, muft make an
effort, at the fame time, to reftore the body to the
ftate it was in wrhen the pores were more patent and
round, i. e. before the bow-was bent: and in this con-
fifts its elafticity.
Other later and more wary philofophers account
fbr elafticity much after the fame manner as the Car¬
tefians j with this only difference, that in lieu of the
fubtile matter of the Cartefians, thefe fubftitute E-
ther^ or a fine ethereal medium that pervades all bo¬
dies.
Others, fetting afide the precarious notion of a ma¬
teria fubtilis, account for elafticity from the great law
of nature attraction, or the caufe of the cohesion of
the parts of folid and firm bodies. Thus, fay they,
when a hayd body is ftruck or bent, fo that the compo¬
nent parts are moved a little from each other, but not
quite disjointed or broke off, or feparated fo far as to
be out of the power of that attraftive force whereby
♦hey cohere j they muft certainly, on the ceffation of
1 639 ]
E L A
the external violence, fpring back to their former na- Elafticity:
tural ftate. v
Others refolve elafticity into the preffure of the at-
mofphere; for a violent tenfion or compreflion, though
not fo great as to feparate the conftituent particles of
bodies far enough to let in any foreign matter, muft yet
occafion many little vacuola between the feparated fur-
faces j fo that upon the removal of the force they will
clofe again by the preffure of the aerial fluid upon the
external parts. See Atmosphere.
Laftly, others attribute the elafticity of all hard bo¬
dies to the power of refilition in the air included with¬
in them : and fo make the elaftic force of the air the
principle of elafticity in all other bodies.
Ihe Elasticity of Fluids is accounted for from thelrv
particles being all endowed with a centrifugal force y
when Sir Ifaac Newton, prop. 23. lib. 2. demonftrates,
that particles, which naturally avoid or fly off from
one another by fuch forces as are reciprocally pro¬
portioned to the diftances of their centre, will com-
pofe an elaftic fluid, whole denfity {hall be propor¬
tional to its compreflion 5 and vice verfa, if any fluid
be compofed of particles that fly off and avoid one
another, and hath its denfity proportional to its com¬
preflion, then the centrifugal forces of thofe par¬
ticles will be reciprocally as the diftances of their
centres.
Elasticity of the Air, is the force wherewith that
element dilates itfelf, upon removing the force vdiere-
by it was before compreffed. See Air and Atmo¬
sphere.
The elafticity or fpring of the air w’as firft difco-
vered by Galileo. Its exiftence is proved by this expe¬
riment of that philofopher: An extraordinary quantity
of air being intruded by means of a fyringe into a
glafs or metal ball, till fuch time as the ball, with
this acceflion of air, weighs conliderably more in the
balance than it did before j upon opening the mouth
thereof,. the air ruffles out, till the ball fink to its for¬
mer weight. From hence wre argue, that there is juft
as much air gone out, as comprefled air had been
crowded in. Air, therefore, returns to its former de¬
gree of expanfion, upon removing the force that com-
preffed or refilled its expanfion ; confequently it is en¬
dowed with an elaftic force. It muft be added, that as
the air is found to rufti our in every fituation or direc¬
tion of the orifice, the elaftic force adls every way, or
in every dire&ion.
The elafticity of the air makes a confiderable article
in Pneumatics.
The caufe of the elafticity of the atmofphere hath
been commonly afcribed to a repulfion between its par¬
ticles 5 but this can give us only a very flight idea of
the nature of its elafticity. The term repu/fon, like
that of attrallion, requires to be defined j and in all pro¬
bability will be found in moft cafes to be the effedl of
the aftion of fome other fluid. Thus, w^e find, that
the elafticity of the atmofphere is very confiderably af-
fefted by heat. Suppofing a quantity of air heat¬
ed. to fuch a degree as is fufficient to raife Fahren¬
heit’s thermometer to 212, it will then occupy a con¬
fiderable fpace. If it is cooled to fuch a degree as to v
fink the thermometer to o, it will fhrink up into lefs
than half the former bulk. The quantity of repulfive
powrer
I
E L B [ 640 ] EL £
Ehte power therefore acquired by the air, while pairing from
one of thefe Hates to the other, is evidently owing to
, the heat added to or taken away from it. Nor have
we any reafon to fuppofe, that the quantity of elafti-
city or repullive power it Hill poffeffes is owing to any
other thing than the fire contained in it. The fuppo-
fing repulfion to be a primary caufe, independent of
all others, hath given rile to many erroneous theories,
and been one very great mean of embarrafling philofo-
phers in their accounting for the phenomena of Elec¬
tricity.
ELATE, a genus of plants belonging to the na¬
tural order of Palmee. See Botany Indeic.
ELATER, a genus of infedts belonging to the or-
order of Coleoptera. See Entomology Index.
ELATERIUM, a genus of plants belonging to
the moncecia clafs. See Botany Index*
Elaterium, in Pharmacy, a violently pur¬
gative medicine, prepared from the wild Cucumber.
ELATH, or Eloth, a port of Idumaea, fituated
upon the Red fea, which David in his conquefl of E-
dom took (2 Sam. viii. 14.), and there eftablifhed a
trade to all parts of the world. His fonj we fee, built
fliips in Elath, and fent them from thence to Ophir for
gold, (2 Chr. viii. 17, 18.). It continued in the poffef-
fion of the Ifraelites about 150 years, till in the time
of Joram, the Edomites recovered it (2 Kings viii.
20.) ; but it was again taken from them by Azariah,
and by him left to his fon, (2 Kings xiv. 22.). His
grandfon Ahaz, however, loll it again to the king of
yria (/#. xvi. 6.) ; and the Syrians had it in their hands
a long while, till after many changes under the Ptole¬
mies, it came at length into the poffelTion of the Ro¬
mans.
ELATlNE, a genus of plants belonging to the oc-
tandria clafs. See Botany Index.
ELATOSTEMA, a genus of plants belonging to
the monoecia clafs. See Botany Index.
ELBE, R large river in Germany, which, riling on
the confines of Silefia, runs through Bohemia, Saxony,
and Brandenburg j and afterwards dividing the duchy
of Luxemburg from that of Mecklenburg, as alfo the
duchy of Bremen from Holftein, it falls into the Ger¬
man ocean, about 70 miles below Hamburg. It is
navigable for great Ihips higher than any river in Eu¬
rope.
ELBlNG, a city of Polilh Pruflia, in the palati¬
nate of Marienburg, fituated in E. Long. 20. o. N.
Lat. 54. 15, on a bay of the Baltic fea, called the
Frifchaff, near the mouth of the Viltula. The town is
large, populous, and very well built. It is divided into
twu parts, called the old and new town, which are
both of them very wrell fortified. The old town has
a handfome tower, with a good college. The ftadt-
houfe and the academy are good buildings, with plea-
fant gardens, which are worth feeing. The place has
a confiderable trade, efpecially in flurgeon, mead,
cheefe, butter, and corn. It is feated in a champaign
level like Holland, very fruitful and populous. The
inhabitants are partly Lutherans and partly Roman
Catholics. The boors in the neighbourhood have as
good houfes and apparel almofl as the nobility of Cour-
land.
ELBOW, the outer angle made by the flexure or
bend of the arm. That eminence whereon the arm
3
refts, called by us elbow, is by the Latins called cubi- Elbcntf
tus, and the Greeks a,yx.m, and by others oAtxjavav. II
Elbow is alfo ufed by architects, mafons, &c. for
an obtufe angle of a wall, building, or road, which di-» , .,]
verts it from its right line.
ELCESAITES, in church hiflory, ancient here-
tict, who made their appearance in the reign of the
emperor Trajan, and took their name from their leader
Elcelai. The Elcefaites kept a mean between the Jewrs,
Chriltians, and Pagans j they worihipped but one
God, obferved the Jewilh fabbath, circumcifion, and
the other ceremonies of the law. They rejected the
Pentateuch, and the prophets: nor had they any more
refpeft for the writings of the apoftles, particularly
thofe of St Paul.
ELDERS, or Seniors, in Jewifh hiftory, were
perfons the molt confiderable for age, experience, and
wifdom. Of this fort were the 70 men whom Mofes
aflbeiated to himfelf in the government of his people i
fuch, likewife, afterwards were thofe who held the firfl:
rank in the fynagogue, as prefidents.
In the firit affemblies of the primitive Chriltians,
thofe who held the firft place were called elders. The
word prejhyter, often ufed in the New Teftament, is of
the fame lignification : hence the firfl; councils of Chri-
ftians were called prejbyteria, or councils of elders.
Elders is alfo a denomination ftill retained in the
Prefbyterian difeipline. The elders are officers, who,
in conjunction with the paflors, or minifters, and dea*
cons, compofe the confiflories or kirk-feflions, meet¬
ing to confider, infpeCt, and regulate, matters of reli¬
gion and difeipline. They are chofen from among the
people, and are received publicly with fome degree of
ceremony. In Scotland, there is an indefinite num¬
ber of elders in each pariih \ generally about 12. See
KiRK-SeJJions and PRESBYTERY.
Elder. See Sambucus, Botany Index.
ELEA, or Elis, in Ancient Geography, a diftrict
of Peloponnefus, fituated between Achaia and Mef-
fenia, reaching from Arcadia quite to the weft or Io¬
nian fea: fo called from Elis, a cognominal town.
See Elis.
ELEATIC philosophy, among the ancients, a
name given to that of the stoics, becaufe taught at
EAe«, in Latin Velia, a town of the Lucani.
The founder of this philofophy, or of the Eleatic
fed, is fuppofed to have been Xenophanes, who lived
about the 56th Olympiad, or between 500 or 600 years
before Chrift. This fed was divided into two parties,
which may be denominated metapby/ical and phyjical,
the one rejecting, and the other approving, the appeal
to faCt and experiment. Of the former kind were Xe¬
nophanes, Parmenides, Meliffus, and Zeno of Elea.
They are fuppofed to have maintained principles not
very unlike thofe of Spinoza j they held the eternity
and immutability of the world} that whatever exifled
was only one being ; that there was neither any gene¬
ration nor corruption \ that this one being was im¬
moveable and immutable, and wras the true God \ and
whatever changes feemed to happen in the univerfe,
they confidered as mere appearances and illufions of
fenfe. Plowever, fome learned men have fuppofed,
that Xenophanes and his followers, fpeaking metaphy-
fically, underftood by the univerfe, or the one being,
not the material world, but the originating principle
E L E [64
Eleeam- or all tilings, or the true God, whom they exp refs! y
pane affirm to be incorporeal. Thus Simplicius reprefents
them as merely metaphyfical writers, who diftinguiffi-
Eketion. between things natural and fupernatural j and who
made the former to be compounded of different prin¬
ciples. Accordingly, Xenophanes maintained, that
the earth confifted of air and fire 5 that all things
were produced out of the earth, and the fun and ftars
out of clouds, and that there were four elements. Par¬
menides alfo diftinguiffiejd between the doclrine con¬
cerning metaphyfical objefts, called trut/i, and that
concerning phyfical or corporeal things, called opinion;
with refpect to the former there was one immoveable
principle, but in the latter two that were moveable,
viz. fire and earth, or heat and cold j in which parti¬
culars Zeno agreed with him. The other branch of
the Eleatic left were the atomic philofophers, who
formed their fyftem from an attention to the phenome¬
na of nature j of thefe the molt confiderable were Leu¬
cippus, Democritus, and Protagoras.
ELECAMPANE. See Inula, Botany Index.
ELECT, (from eligo, “ I choofe”) Chosen, in the
Scriptures, is applied to the primitive Chriftians, in
which fenfe, the eleft are thofe chofen and admitted to
the favour and bleffing of Chriftianity.
Elect, in fome fyftems of theology, is a term ap¬
propriated to the faints, or the predeftinated : in which
lenfe the eleft are thofe perfons who are faid to be pre¬
deftinated to glory as the end, and to fanftification as
the means.
Elect is likewife applied to archbiffiops, bilhops,
and other officers, who are chofen, but not yet confe-
crated, or aftually invefted with their office or jurif-
diftion.
The emperor is faid to be eleft before he is inaugu¬
rated and crowned •, a lord-mayor is eleft, before his
predeceffor’s mayorality is expired, or the fword is put
is his hands.
ELECTION, the choice that is made of any thing
or perfon, -whereby it is preferred to fome other.
There feems this difference, however, between choice
and eleftion, that eleftion has ufually a regard to a
company or community, which makes the choice ;
whereas choice is feldom ufed but when a fingle per¬
fon makes it.
Election, in Britilh polity, is the people’s choice
of their reprefentatives in parliament. (See Parlia¬
ment.) In this confifts the exercife of the democra-
tical part of our conftitution: for in a democracy there
can be no exercife of fovereignty but by fuffrage, which
is the declaration of the people’s will. In all democra¬
cies, therefore, it is of the utmoft importance to regu¬
late by whom, and in what manner, the luffrages are
to be given. And the Athenians were fo juftly jealous
of this prerogative, that a ftranger, who interfered in
the affemblies of the people, was puniffied by their
laws with death ; becaufe fuch a man was efteemed
guilty of high treafon, by ufurping thofe rights of
Blatljlonts fovereignty to which he had no title. In Britain,
Comment, where the people do not debate in a colleftive body,
but by reprefentation, the exercife of this fovereignty
•confifts in the choice of reprefentatives. The laws
have therefore very ftriftly guarded againft ufurpation
or abufe of this power, by many falutary provi-
fions; which may be reduced to thefe three points,
yoL. VII. Part IL
i ] E L E
1. The qualifications of the eleftors. 2. The* qua¬
lifications of the elefted. 3. The proceedings at
eleftions.
(1.) As to the qualifications of the eleftors. The
true reafon of requiring any qualification, with regard
to property, in voters, is to exclude fuch perfons as are
in fo mean a fituation, that they are efteemed to have
no will of their own. If thefe perfons had votes, they
would be tempted to difpofe of them under fome un¬
due influence or other. This tvoukl give a great, an
artful, or a wealthy man, a larger ffiare in eleftions
than is conliftent with general liberty. If it were pro¬
bable that every man would give his vote freely, and
without influence of any kind j then, upon the true
theory and genuine principles of liberty, every member
of the community, however poor, flrould have a vote in
elefting thofe delegates to whofe charge is committed
the difpofal of his property, his liberty, and his life.
But fince that can hardly be expefted in perfons of
indigent fortunes, or fuch as are under the immediate
dominion of others, all popular fiates have been obli¬
ged to eftablilh certain qualifications j whereby fome,
who are fufpefted to have no will of their own, are ex¬
cluded from voting, in order to fet other individuals,
whofe will may be fuppofed independent, more tho¬
roughly upon a level with each other.
And this conftitution of fuffrages is framed upon a
wifer principle with us, than either of the methods
of voting, by centuries, or by tribes, among the Ro¬
mans. In the method by centuries, inftituted by Ser-
vius Tullius, it was principally property, and not num¬
bers, that turned the fcale : in the method by tribes,
gradually introduced by the tribunes of the people,
numbers only were regarded, and property entirely
overlooked. Hence the law's paffed by the former me¬
thod had ufually too great a tendency to aggrandize
the patricians or rich nobles; and thofe by the latter
had too much of a levelling principle. Our conftitu¬
tion fleers between the two extremes. Only fuch are
entirely excluded as can have no will of their own :
there is hardly a free agent to be found, but what is
intitled to a vote in fome place or other in the king¬
dom. Nor is comparative wealth, or property, entire¬
ly difregarded in eleftions \ for though the richeft man
has only one vote at one place, yet, if his property be
at all diffufed, he has probably a right to vote at more
places than one, and therefore has many reprefentatives.
This is the fpirit of our conftitution \ not that we affert
it is in faft quite fo perfeft as we have endeavoured to
deferibe it 5 for if any alteration might be wilhed or
fuggefted in the prefent form of parliaments, it ftiould
be in favour of a more complete reprefentation of the
people.
But to return to the qualifications ; and firft thofe
of eleftors for knights of the {hire. 1. By ftatute
8 Hen. VI. c. "j. and 10 Hen. VI. c. 2. (amended by
14 Geo. III. c. 58.) the knights of the {hire ftiall be
chofen of people, whereof every man fhall have free¬
hold to the value of forty {hillings by the year within
the county *, which (by fubfequent ftatutes) is to be
clear of all charges and deduftibns, except parliamen¬
tary and parochial taxes. The knights of {hires are
the reprefentatives of the landholders, or landed inte-
reft of the kingdom : their eleftors muft therefore have
eftates in lands or tenements within the county repre-
4 M " 1 fented;
E L E [ 642 ] E L E
■Rledtion. fenteJ. Thefe eftates mull be freehold, that is, for term
v of life at leaf! j becaufe beneficial leafes for long terms
of years were not in ufe at the making of thefe fta-
tutes, and copyholders were then little better than vil¬
lains, abfolutely dependent upon their lords. This free¬
hold mull be of 40 fhillings annual value 5 becaufe
that fum would then, with proper induftry, furnilh all
the necefiaries of life, and render tbe freeholder, if he
pleafed, an independent man : For Bilhop Fleetwood,
in his Chronicon Preciojum, written at the beginning of
the lafi: century, has fully proved 40 (hillings in the
reign of Henry VI. to have been equal to 1 2 pounds
per annum in the reign of Queen Anne ; and, as the
value of money is very confiderably lowered fince the
bifhop wrote, we may fairly conclude, from this and
other circumltances, that what was equivalent to 12
pounds in his days, is equivalent to 20 at prefent. The
other lefs important qualifications of the eleftors for
counties in England and Wales may be collcfted from
the flatutes cited below (a) } which diredl, 2. That no
perfon under 21 years of age fhall be capable of voting
for any member. This extends to all forts of mem¬
bers as wrell for boroughs as counties; as does alfo
the next, viz. 3. That no perfon conviifed of per¬
jury, or fubornation of perjury, fhall be capable of
voting in any eleftion. 4. That no perfon fhall vote
in right of any freehold, granted to him fraudulently,
to qualify him to vote. Fraudulent grants are fuch as
contain an agreement to re-convey, or to defeat the
eflate granted ; which agreements are made void, and
the ellate is abfolutely veiled in the perfon to wrhom it
is fo granted. And, to guard the better againll fuch
frauds, it is further provided, 5. That every voter fhall
have been in the actual pofleflion, or receipt of the pro¬
fits, of his freehold to his own ufe for 12 kalendar
months before j except it came to him by defcent, mar¬
riage, marriage fettlement, will, or promotion to a
benefice or office. 6. That no perfon fhall vote in re-
fpefl of an annuity or rent-charge, unlefs regiffered
with the clerk of the peace 12 kalendar months before.
7. That in mortgaged or trufl eflates, the perfon in
poffeffion, under the above-mentioned reflriclions, fhall
have the vote. 8. That only one perfon fhall be ad¬
mitted to vote for any one houfe or tenement, to pre-
vent the fplitting of freeholds. 9. That no eflate fhall
qualify a voter, unlefs the eflate has been aflefled to
fome land-tax aid, at leaf! 1 2 months before the elec¬
tion. 10. That no tenant by copy of court-roll fhall
be permitted to vote as a freeholder. Thus much for
the ele£lors in counties.
As for the eleflors of citizens and burgeffes, thefe
are fuppofed to be the mercantile part or trading inte-
refl of this kingdom. But as trade is of a fluftuating
nature, and feldom long fixed in a place, it was for¬
merly left to the crowm to fummon, pro re nata, the mod
flouriffiing towms to fend reprefentatives to parliament.
So that as towns increafed in trade, and grew popu¬
lous, they wrere admitted to a (hare in the legiflature.
But the misfortune is, that the deferted boroughs con¬
tinued to be fummoned, as well as thofe to whom their
trade and inhabitants wTere transferred ; except a few Ele<ftion.
which petitioned to be eafed of the expence, then ufual, l—-y-—■“
of maintaining their members : four (hillings a-day
being allowed for a knight of the (hire, and two (hil¬
lings for a citizen or burgefs j which was the rate of
wages eflablifhed in the reign of Edurard III. Hence
the members for boroughs now bear above a quadruple
proportion to thofe for counties 5 and the number of
parliament men is increafed fince Fortefcue’s times, in
the reign of Henry VI. from 300 to upwards of jco,
exclufive of thofe for Scotland. The univerfities were,
in general, not empowered to fend burgeffes to parlia¬
ment •, though once, in 28 Edw. I. when a parliament
was fummoned to confider of the king’s right to Scot¬
land, there were ifiued writs, which required the uni-
verfity of Oxford to fend up four or five, and that of
Cambridge two or three, of their mod difcreet and
learned lawyers for that purpofe. But it w7as King
James I. who indulged them with the permanent pri¬
vilege to fend conflantly two of their own body j to
ferve for thofe fludents wffio, though ufeful members
of the community, were neither concerned in the land¬
ed nor the trading interell 5 and to protect in the le-
giflature the rights of the republic of letters. The
right of eledtion in boroughs is various, depending en¬
tirely on the feyeral charters, cufloms, and conflitu-
tions of the refpedlive places ; which has occafioned
infinite difputesq though now, by flatute 2 Geo. II.
c. 24. the right of voting for the future fhall be allow¬
ed according to the lafl determination of the houfe of
commons concerning it \ and, by flatute 3 Geo. III.
c. 13. no freeman of any city or borough (other than
fuch as claim by birth, marriage, or fervitude) fhall be
intitled to vote therein, unlefs he hath been admitted
to his freedom 1 2 kalendar months before.
(2.) Next, as to the qualifications of perfons to be
eletted members of the houfe of commons. Some of
thefe depend upon the law and cuflom of parliaments,
delated by the houfe of commons j others upon cer¬
tain flatutes. And from thefe it appears, 1. That
they muff not be aliens born or minors. 2. That they
muff not be any of the 1 2 judges, becaufe they fit in
the lords’ houfe •, nor of the clergy, for they fit in the
convocation ; nor perfons attainted of treafon, or fe¬
lony, for they are unfit to fit anywhere. 3. That fhe-
riffs of counties, and mayors and bailiffs of boroughs,
are not eligible in their refpedlive jurifdidlions, as be¬
ing returning officers ; but that fheriffs of one coun¬
ty are elligible to be knights of another. 4. That,
in flridlnefs, all members ought to have been inhabi¬
tants of the places for which they are chofen ; but this,
having been long difregarded, was at length entirely
repealed by flatute 14 Geo. III. c. 58. 5. That no
perfons concerned in the management of any duties or
taxes created fince 1692, except the commiffioners of
the treafury, nor any of the officers following (viz.
commiffioners of prizes, tranfports, lick and wounded,
wine licenfes, navy, and vicluailing j fecretaries or re
ceivers of prizes ; comptrollers of the army accounts ^
agents for regiments 5 governors of plantations, and
their
(a) 7 and 8 Will. III. c. 25. 10 Ann. c. 23. 2 Geo. II. c, 21. 18 Geo. II.. c. 18. 31 Geo. II. c. 14-
3 Geo. III. c. 24.
E L E
[ 643 ]
E L E
Election, tlieir deputies ; officers of Minorca or Gibraltar ; offi-
1   1 cers of the excife and cuftoms; clerks or deputies in
the feveral offices of the-treafury, exchequer, navy,
victualling, admiralty, pay of the army or navy, fecre-
taries of date, fait, damps,, appeals, wine-licenfes,
hackney-coaches, hawkers, and pediars), nor any per-
fons that hold any new office under the crowm created
fince 1705, are capable of being elefted or fitting as
members. 6. That no perfon having a penlion under
the crowm during pleafure, or for any term of years,
is capable of being elefted or fitting. 7. That if any
member accepts an office under the crown, except an
officer in the army or navy accepting a newr commiffion,
his feat is void •, but fuch member is capable of being
re-eleaed. 8. That all knights of the ihire ffiall be
aaual knights, or fuch notable efquires and gentlemen
as have efiates iufficient to be knights, and by no means
of the degree of yeomen, ihis is. reduced to a Hill
greater certainty, by ordaining, 9. I hat every knight
of a ihire ihall have a clear eilate of freehold or copy-
hold to the value of 600I. per annum, and every citi¬
zen and burgefs to the value of 30°^ • except tlm e^_
ded fons of peers and of perfons qualified to be knights
of ffiires, and except the members for the two univer-
fities j which fomewyhat balances the afcendant which
the boroughs have gained over the counties, by obli¬
ging the trading intered to make choice oi landed
men : -and of this qualification the member mud make
oath, and give in the particulars in writing, at the time
of his taking his feat. But, lubjeft to thefe Handing
redactions and difqualifications, every fubject of the
realm is eligible of common right : though there are
indances, wherein perfons in particular circumdances
have forfeited that common right, and have been de¬
clared ineligible for that parliament, by a vote of the
houfe of commons, or for ever, by an a£t of the ]e_gif-
lature. But it was an unconditutional prohibition,
which was grounded on an ordinance of the houle of
lords, and inferted in the king's writs, for the parlia¬
ment holden at Coventry, 6 Hen. IV. that no appren¬
tice or other man of the law ihould be elefred a knight
for the (hire tiaerein : in return for which, our law¬
books and hidorians have branded this parliament with
the name of parliamentum indo&um, or the lack-learning
parliament} and Sir Edward Coke obferves with fome
fpleen, that there was never a good law made thereat.
(3.) The third point, regarding elections, is the
method of proceeding therein. 1 his is alio regulated
by the law of parliament, and the feveral datutes re-
rerred to in the margin below (b) j all which we diall
blend together, and extract out of them a. fummary
account of the method of proceeding to elections.
As foon as the parliament is fammoned, the lord
chancellor (or if a vacancy happens during the fitting
of parliament, the fpeaker, by order of the houle, and
without fuch order if a vacancy happens by death in
the time of a recefs for upwards of 20 days) fends his
warrant to the clerk of the crown in chancery j w'ho
thereupon iffues out writs to the Iheriff of every coun¬
ty, for the election of all the members to ferve for that
county, and every city and borough therein. Within
three days after the receipt of this writ, the Hieriff is to
fend his precept, under his feal, to the proper return¬
ing officers of the cities and boroughs, commanding
them to cleft their members: and the faid returning,
officers are to proceed to eleftion within eight days
from the receipt of the precept, giving four days no¬
tice of the fame ; and to return the perfons chofen, to¬
gether with the precept, to the iheriff.
But eleftions of knights of the (hire mud be pro¬
ceeded to by the Iheriffs themfelves in perfon, at the
next county-court that ffiall happen after the delivery
of the writ. The county court is a court held every
month or oftener by the Iheriff, intended to try little
caufes not exceeding the value of 40s. in what part of
the county he pleafes to appoint for that purpofe : but
for the eleftion of knights of the dure, it mud be held
at the mod ufual place. If the county-court fails up¬
on the day of delivering the wrrit, or within fix days
after, the iheriff may adjourn the court and eleftion
to fome other convenient time, not longer than 16
days, nor Ihorter than 10 : but he cannot alter the
place, without the confent of all the candidates 5 and,
in all fuch cafes, 10 days public notice mud be given
of the time and place of the eleftion.
And, as it is effential to the very being of parlia¬
ment that eleftions ffiould be abfolutely free, therefore
all undue induences upon the eleftors are illegal, and
drongly prohibited. For Mr Locke ranks it among
thofe breaches of trud in the executive magidrate,
which, according to his notions, amount to a diliolu-
tion of the government, “ if he employs the force,
treafune, and offices of the fociety to corrupt the re-
prefentatives, or openly to pre-engage the eleftors, and
prefcribe what manner of perfons ffiall be chofen : For
thus to regulate candidates and eleftors, and new-model
the ways of eleftion, wffiat is it (fays he) but to cut up
the government by the roots and poifon the very foun¬
tain of public fecurity ?” As foon, therefore, as the
time and place of eleftion, either in counties or
boroughs, are fixed, all foldiers quartered in the place
are to remove, at lead one day before the eleftion, to
the didance of two miles or more 5 and not to return
till one day after the poll is ended. Riots likewife
have been frequently determined to make an eleftion
void. By vote alfo of the houfe of commons, to whom
alone belongs the power of determining conteded
eleftions, no lord of parliament, or lord-lieutenant of
a county, hath any right to interfere in the eleftion
of commoners \ and, by datute, the lord warden of
the cinque-ports diall not recommend any members
there. If any officer of the excife, cudoms, damps, or
certain other branches of the revenue, prefumes to in¬
termeddle in eleftions, by perfuading any voter or
diffuading him, he forfeits tool, and is difabled to hold
any office.
a M 2 Thus
Eleftlhn.
(b) 7 Hen. IV. c. 15. 8 Hen. VI. c. 7. 23 Hen. VI. c. 14. 1 W. & M. d. 1. c. 2. 2 W. & M. d. 1. c. 7.
5 and 6 W. & M. c. 20. 7 W. III. c. 4. 7 and 8 W. III. c. 7. and c. 25. 10 & 11 W. III. c. 7. 12 and 13 W. IjL
c. 10. 6 Ann. c. 23. 9 Ann. c. 5. 10 Ann. c. 19. and c. 33. 2 Geo. II. c. 24. 8. Geo. II. c. 30. 18 Geo. IT
c. 18. 19 Geo. II. c. 28. 10 Geo. III. c. 16, 11 Geo. III. c. 42. 14 Geo. HI. c. 1;.
E L E
. Election. Thus are tlve ele<fl:ors of one brancli of the legifla-
ture fecured from any undue influence from either of
the other two, and from all external violence and com-
pulfion. But the greateft danger is that in which
themfelves co-operate, by the infamous pra&ice of
bribery and corruption. To prevent which it is en-
atfed, that no candidate fhall, after the date (ufually
called the tejlc) of the writs, or after the vacancy,
give any money or entertainment to his electors, or
promxfe to give any, either to particular perfons, or
to the place in general, in order to his being ele&ed;
on pain of being incapable to ferve for that place in
parliament. And if any money, gift, office, employ¬
ment, or reward be given, or promifed to be given,
to any voter, at any time, in order to influence him
to give or withhold his vote, as well he that takes as
he that offers fuch bribe forfeits 500I. and is for ever
difabled from voting and holding any office in any
corporation *, unlefs, before convi&ion, he will dif-
cover fome other offender of the fame kind, and
then he is indemnified for his own offence. The firff
inftance that occurs of eledlion bribery, was fo early
as 13 Eliz. when one Thomas Longe (being a Ample
man, and of fmall capacity to ferve in parliament) ac¬
knowledged that he had given the returning officer
and others of the borough for which he was chofen
four pounds to be returned member, and was for that
premium elected. But for this offence the borough
was amerced, the member was removed, and the officer
fined and imprifoned. But as this practice hath lince
taicen much deeper and more univerfal root, it hath
occafioned the making of thefe wholefome ffatutes ;
to complete the efficacy of which, there is nothing
wanting but refolution and integrity to put them in
itrict execution.
Undue influence being thus guarded againft, the
election is to be proceeded to on the day appointed j
the iheriff or other returning officer firff taking an oath
againft bribery, and for the due execution of his office.
The candidates likewife, if required, muft fwear to their
qualification, and the electors in counties to theirs y and
the elefftors both in counties and boroughs are alfo com¬
pellable to take the oath of abjuration, and that againft:
bribery and corruption. And it might not be amifs,
if the members eledfed were bound to take the latter
oath as well as the former j which, in all probability,
would be much more effeftual than adminiftering it only
to the electors.
The ele&ion being clofed, the returning officer in
boroughs returns his precept to the fheriff, with the
perfons defied by the majority : and the flieriff re¬
turns the whole, together with the writ for the county
and the knights defied thereupon, to the clerk of the
crown in chancery; before the day of meeting, if it
be a new parliament, or within 14 days after the elec-
tion* if it be an occafional vacancy 5 and this under
penalty of 500I. If the flieriff does not return fuch
t knights only as are duly defied, he forfeits, by the
old ftatutes of Henry VI. look; and the returning
officer in boroughs, for a like falfe return, 40I. ; and
they are beftdes liable to an aflion, in which double
damages fhall be recovered, by the later ftatutes of
King William : and any perfon bribing the returning
officer ffiall alfo forfeit 300I. But the members re¬
turned by him are the fitting members, until the houfe
E L E
of commons, upon petition, fhall adjudge the return Election
to be falfe and illegal. The form and manner of pro- !l
ceeding upon fuch petition are now regulated by fta- £hacr.
tute 10 Geo. Ill, c. 16. (amended by 1 x Geo. HI. v
c. 42. and made perpetual by 14 Geo. III. c. 15.),
which direfts the method of choofing by lot a felefl
committee of 15 members, who are fworn well and
truly to try the fame, and a true judgment to give, ac¬
cording to the evidence.
Election of Scots Peers. See Lords.
. Election of Ecclefmjiical Perfons. Eleflions for the
dignities of the church ought to be free, according to
the flat. 9. Ed. II. cap. 14. If any perfons, that have
a voice in eleflions, take any reward for an eleaion in
any church, college, fchool, &c. the eleflion fhall be
void. And if any perfons of fuch focieties refign their
places to others for reward, they incur a forfeiture of
double the fum ; and both the parties are rendered in¬
capable of the place. Stat. 31 Eliz. cap. 6.
Election of a Verderor of the Forejl (eiefhone viri-
darwrum Jorejlcc f m PaiVy a writ that lies for the choice
of a verderor, where any of the verderors of the foreft
are dead, or removed from their offices. This writ is
direfled to the ffieriff, and the verderor is to be elec¬
ted by the freeholders of the county, in the fame man¬
ner as coroners. New. Nat. Brev. 366.
Election is alfo the ftate of a perfon who is left to
his own free will, to take or do either one thing or an¬
other, -which he pleafes. See Liberty.
Election, in Theology, fignifies the choice which
God, of his good pleafure, makes of angels or men,
for the objefls of mercy and grace.
The election of the Jews was the choice God made
of that people to be more immediataly attached to his
worfhip and fervice, and for the Meffiah to be born
of them. And thus particular nations were elected to
the participation of the outward bleffings of Chriftia-
nity.
Election alfo, in the language of fome divines, flg~
nifies a predeftination to grace and glory, and fometimes
to glory only. And it has been enjoined as an article
of faith, that predeftination to grace is gratuitous,
merely and Amply fo •, gratia, quia gratis data. But the
divines are much divided as to the point, whether elec¬
tion to glory be gratuitous, or whether it fuppofes obe¬
dience and good works, i. e. whether it be before or
after the proviAon of our obedience. See Grace and
Reprobation.
ELECTIVE, fomething that is done, or pafles, by
eleilion. See Elector.
Some beneAces are ele<5live, others collative. Mu¬
nicipal offices in England are generally ele&ive ; in
Spain, venal. Poland is an ele(Stive kingdom.
Elective AttraElion. See Chemistry Index.
ELECTOR, a perfon who has a right to ele<St or
choofe another to an office, honour, &c. See Elec¬
tion.
Elector is particularly, and by way of eminence,
applied to thofe princes of Germany in whom lies the
right of electing the emperor; being all fovereign
princes, and the principal members of the empire.
The elecSloral college, conAfting of-all the eledors of
the empire, is the moft illuftrious and auguft body in
Europe. Bellarmine and Baronius attribute the infti-
tution of it to Pope Gregory V. and the emperor O-
tho
[ <44 ]
E L E
Eleftor. tlio III. in the tenth century j of which opinion are
““ v " 1 the generality of hiilorians, and particularly the ca-
nonilts: however, the number of eleclors was unfet¬
tled, at lea ft, till the 13th century. In 1356 Charles IV.
by the golden bull, fixed the number of eledors to
feven 5 three ecclefiaftics, viz. the archbifhops of Mentz,
Treves, and Cologne j and four fecular, viz. tne hing
of Bohemia, count Palatine of the Rhine, duke of
Saxony, and marquis of Brandenburg. In 1648 this
order was changed, the duke of Bavaria being put in
the place of the count Palatine, who having accepted
the crown of Bohemia was outlawed by the emperor j
but being at length reftored, an eighth eleftorate was
erefted for the duke of Bavaria. In 1692, a ninth e-
ledlorate w^as created, by the emperor Leopold, in fa¬
vour of the duke of Hanover, of the houfe of Brunfwic
Lunenburg.
There is this difference between the fecular and ec-
clefiaftical electors, that the firft have an aftive and
paffive voice, that is, may choofe and be chofen } the
laft an active only. The three archbifhops are to be
30 years old before they can be advanced to the dig¬
nity ; the feculars 18, before they can perform the of¬
fice themfelves. Thefe laft: have each their vicars, who
officiate in their abfence.
Befides the powTer of choofing an emperor, the elec¬
tors have alfo that of capitulating with and depofing
him ; fo that, if there be one fuffrage wanting, a pro-
teft may be entered againft the proceedings. By the
right of capitulation, they attribute to themfelves great
privileges, as making of wTar, coining, and taking care
of the public intereft and fecurity of the ftates j and the
E L E
emperor promifes, upon oath, to receive the empire up- Eieifkirate
on thefe conditions. _ Ele&ridty
The ele£lors have precedence of all other princes of.
the empire, even of cardinals and kings j and are ad-
dreffed under the title of eleEioral highnejs.
Their federal functions are as follow. The elector of
Mentz is chancellor of Germany, convokes the ftates,
and gives his vote before any of the reft. The eleHor
of Cologne is grand chancellor of Italy, and confe-
crates the emperor. The elector of Treves is chancel¬
lor of the Gauls, and confers impofition of hands upon
the emperor. The count Palatine of the Rhine is great
treafurer of the empire, and prefents the emperor with
a globe at his coronation. The elector of Bavaria is
great mafter of the imperial palace, and carries the gol¬
den apple. The marquis of Brandenburg is grand-
chamberlain, and puts the ring on the emperor’s finger.
The elector of Saxony is grand marlhal, and gives the
fword to the emperor. The king of Bohemia is grand
butler, and puts Charlemagne’s crown on the emperor’s
head. Laftly, the eleftor of Hanover, now king of
Great Britain, is arch treafurer, though firft ere&ed
under the title of Jlandard-bearer of the empire.
ELECTORATE, a term ufed as w-ell to fignify
the dignity of, as the territories belonging to, any of
the ele&ors of Germany ; fuch are Bavaria, Saxony,
&c. See Elector.
ELECTRIC, derived from “ amber,” in
phyfics, is a term applied to thole fubftances, in which
the eleftric fluid is capable of being excited, and accu¬
mulated without tranfmitting it, and therefore called
non-conduftors. See Electricity.
[ 645 ]
ELECTRICITY.
INTRODUCTION.
General Principles.
General TXT’HEN a glafs tube of confiderable fize, perfectly
idea ot elec- ^ ’ clean and dry, is rubbed brilkly with a dry hand,
tricity. an(j immediately held over fmall pieces of paper, ftraws,
feathers, or other light bodies, it wdH attract them, and
after retaming them in contadft with it for fome time,
repel them j and this attraction and repulfion will be
alternately repeated feveral times.
If after rubbing the tube, the knuckle be prefented
to the clofed end, a fnapping noife wall be heard, and
the finger will receive a flight {hock. When this ex¬
periment is made in the dark, a luminous fpark will
appear at the moment the fnap is heard, between the
2 finger and the tube.
Metftricj. Many other fubftances poflefs the property of attraft-
ing light bodies and emitting fparks, wflien rubbed
with certain other fubftances, as amber, fealing-wax,
rofin, &c. As amber was firft obferved to poffefs
them, the bodies which are capable of exhibiting fimi-
lar appearances have been termed Electrics, from
»iA8*]§ev, amber; and the fcience which illuftrates and
explains thefe phenomena is denominated ELECTRICI¬
TY (A)- „ . . . t 3
We lhall not at prefent attempt any inquiry into the Elecftrk
caufe of thefe phenomena, but lhall content ourfelves Power*
with calling the power by which they are produced,
the eleSlric power, referving any inveftigation of the
nature of this power for a future part of this article, in
which wTe lhall treat of the theory of eleftricity. The
term cleffricity, which is moll properly applicable to
the fcience, is alfo fometimes applied to the caufe of
the phenomena, or wThat we here call the eleElric
power. 4
When eleflrics are made, by rubbing, to Ihew the Excitation.-
aftion of the eleftric power, they are laid to be excited. <.
There are many fubftances which are incapable of Non-elec¬
being excited, fo as to produce eleftrical appearances,tries or con-
and are therefore non-eleflrics ; but which being pla-
ced near or in contact with an excited eleftric, receive
from
(a) The attracting power of amber w7hen rubbed, is faid to have been known to Thales the
pher, 600 years before ChrilL
Milclian philofo-
MS ELECT
Princol'l ^rom a Porti°n the eleEiric power, and are thus
^ iincip < s ^ maje capable 0f producing the fame appearance as the
electric. Ihus if a metallic rod or wire pointed at one
end and rounded at the other, be attached by the
pointed extremity to an excited eleEiric, or even placed
very near this, the rounded extremity will attract light
bodies, and emit fparks. As thefe fubltances are found
to convey or conduEl the eleEiric power to any diftance
in proportion to their length, they are called conduEiors.
It is found that all bodies in nature are either elec¬
trics or conduEiors. Neither of thefe clafies of bodies
are, however, perfeft elettrics or conduftors, as there
are tew eledlrics which may not under fome circum-
ftances be made to a£l as conductors, and on the other
hand, many conductors may be fo far excited as to be¬
come in fome meafure eleCtrics per fe (b). The fol¬
lowing table exhibits the eleCtrics and conductors ar¬
ranged according to their degree of eleCtrical or con¬
ducting power.
Electrics.
Glafs and all vitrifications, even the metallic vitrifica¬
tions.
All precious {tones, of which the molt tranfparent are
the belt.
Amber.
Sulphur.
All refinous fultances.
Wax.
Silk.
Cotton.
Several dry and external animal fubftances, as feathers,
wool, hair, &c.
Paper.
White fugar, and fugar-candy.
Air, and other permanently elaltic fluids.
Oils.
Dry and complete oxides of metallic fubftances.
The afhes of animal and vegetable fubitances.
Dry vegetable fubftances.
Moft hard {tones, of which the hardeft are the belt.
Conductors.
Gold.
Silver.
Copper.
Platina.
Brafs.
Iron.
Tin.
Quickfilver.
Lead.
Semi-metals, more or lefs.
Metallic ores, more or lefs.
Charcoal, either of animal or of vegetable fubftances.
The fluids of an animal body.
R I c I T Y. Introd.
Water (efpecially fait water),’and all fluids, excepting General
the aerial, and oils. Principles.
The effluvia of flaming bodies. . ¥ *
Congealed water, viz. ice or fnow.
Moft faline fubftances, of which the metallic falts are
the belt.
Several earthy or ftony fubftances.
Smoke.
The vapour of hot water.
Electricity pervades alfo fuch a vacuum, or abfence of
air, as is caufed by the belt air-pump ; but- not the
perfeCt abfence of air, or the torricellian vacuum,
formed by boiling the quickfilver in a barometer
tube. dlavalh'-s
Many of the fubftances given in the above table are
found to change their nature under certain circumftances.
Thus, among the eleCtrics, glafs heated to rednefs, melt¬
ed refins, baked wood when very hot, and heated air,
are tolerably good conductors} and glafs, which is ufual-
ly the belt eleCtric, is fometimes from caufes which have
not been well afcertained a very bad eleCtric. The
excitability of glafs veflels is found to differ according
to the degree of rarefaCtion of the included air ; when
this is rarefied as much as poflible, the external furface
of the veffel cannot be excited, while the internal fur-
face exhibits ftrong marks of eleEiric power ; but when
the included air is confiderably condenfed, the internal
furface (hews no marks of eleCtric power, while the
external is much more excitable than ufual.
Among the conductors, the conducing power of
charcoal varies in proportion to the degree of heat to
which it has been expofed in the making, as, when im-
perfeCtly burned, it is a bad conductor. Indeed it is
worth remarking here, that wood is capable of being
made an eleCtric or a conductor feveral times alternate¬
ly according to its ftate. When frefh cut, it is a good
conduEior : thoroughly dried by baking, it becomes, as
we have feen an eleEiric; burned to charcoal, it is again
a conductor j but when reduced to afhes, it is once
more made an eleEiric.
Ice (c) is placed among the conductors : but in an
experiment of M. Achard, it appeared that when diftil-
led water was gradually frozen, fo that one fide of the
veffel retained it fluid, and therefore permitted the air
to efcape, the ice thus., produced would not conduCt,
but on the contrary became a very good eleCtric, and
was employed as fuch. Snow is a much worfe con¬
ductor than ice. Water is a conductor, and fo are the
fecondary falts j it is found that when water is impreg¬
nated with a lalt, its conducting power is much in-
creafed.
We have, after Mr Cavallo, placed the falts among
conductors) but in ftriCt propriety, this conducting
power muft be confined to falts in the ftate of cryftals,
as it has been proved by decifive experiments, that
falts,
Pbilofophy,
vol. 3.
(b) The difference between eleCtrics and conductors was firft obferved by Mr Stephen Grey in 1759, but the
terms conduEior and eleEiric per fe, were firft employed in this prefent fenfe by Dr Defaguliers.
(c) The conducting power of common ice was firft {hewn by M. Jallabert, profeffor of philofophy at Geneva j
there,feem, however, to have been various opinions refpeCting this faCts till it was fully afcertained by Dr Prieftley.
Vid. Brief lefs Hfory of EleEiricity, Part viii. feCt. 4.
2
Introd. E
General falts, when deprived of their water of cryflallization,
Principles, become non-condu£tors. The conducting power of
' v ' crydallized falts is therefore probably owing to the
6 water which they contain.
Infulation. Electrics are called non-conduttors, as they do not
readily tranfmit eleclric power; they may hence be
employed to check the paffage of this power, or td con¬
fine its influence. When a body communicates with a
conducting fubftance, as the earth, a table, the human
body, &c. the electric power eafily paffes oft'j but when
it is fupported by an electric, the power may be retain¬
ed for a confiderable time. In this latter cafe the body
is faid to be infulated.
We have feen (i, 3), that fire or light appears to
ifliie from an excited electric; and this appearance is
ftronger in proportion to the fize of the electric, and the
degree of friction which it has undergone. When a
rounded body, as the knuckle or a metallic ball, is
prefented to the excited electric, the fire appears to
dart from it in a fpark ; but if the prefented body be
pointed, the fire will appear to iffue in a ftream com-
pofed of luminous rays. Thefe rays will take a dif¬
ferent direction, according to the fubftance with which
the electric is rubbed, and other circumftances which
will be explained hereafter. In the cafe of the glafs
tube rubbed with the hand, when a pointed body, as a
needle, or wire, is prefented to the tube, the luminous
rays will appear like aJlar around the point. The
fame appearance will take place on prefenting a point
to a Hick of fealing-wax rubbed with any metallic body,
as a piece of tin foil ; but when the fealing-wax is rub¬
bed with a piece of woollen cloth, the rays will appear
to iflue from the point in a pencil diverging towards the
wax. In feme experiments which will afterwards be
deferibed, the ftream of fire appears in an evident cur¬
rent in a direction from the eleflric in fome cafes, as in
the tube excited as above, and towards the eledlric in
^ others, as in the wax rubbed with the woollen cloth.
Pofitive and Thefe different appearances have been fuppofed owing
negative e- to two different ftates of the eleBric power, and thefe
le&ricity, fl-ates have been called the two electricities. As in the
former cafe, the fire feems to flow from the glafs into
the metallic body, as if there wras an excefs in the for¬
mer, the glafs is faid to be electrified plus, or pojitivehj,
and this is called pojitive eleBricity. In the latter cafe,
as the ftream appears to Row from the point into the
fealing-wax, as if there were a deficiency in the latter,
g the fealing-wax is faid to be eleftrified minus, or nega-
or vitreous an(^ '•bis is called the negative eleBricity : As
and refinous when glafs is rubbed with molt fubftances, pofitive,
eledtricity. eleftricity is excited, and negative when refinous bodies
are rubbed with moft fubftances, the former is often
called vitreous, and the latter refinous electricity.
The difference of thefe two ftates of the eleCfric
power may be further illuftrated by the following fimple
experiment.
Plate Let a ftem of glafs (A, B. fig. I.) be fixed in a
CLXXXVII wooden pedeftal C. Through the upper extremity A,
pafs a wire A, D, with a rounded end at D, and from
this end fufpend twTo very fine filken threads a, b.
Thefe threads in the ufual ftate of the inftrument will
hang in the parallel pofition a, b, but if the end of the
L E C T R I C I T Y.
wire to which they are attached be prefented to the ex¬
cited tube, the threads will diverge from each other,
and take a pofition as at c, d. If in this diverging
ftate they are prefented to an excited ftick of fealing-
wax, they will collapfe into their original pofition.
Again, the threads prefented firft to the excited feal¬
ing-wax will diverge, but prefented in this ftate to the
excited tube will collapfe, thus Ihowing that thefe two
ftates are oppofite to each other, each deftroying the
effeCt produced by the other.
The following table fhows what kind of electricity
will be excited by rubbing various electrics with differ¬
ent bodies.
64?
General
Principles,
The back of a
cat
Smooth glafs
Rough glafs
Tourmalin
Hare’s fkin
White filk
Black filk
Sealing-wrax
Baked wood
C p0£tjve f Every fubftance with which
* L E has been hitherto tried.
{f Every fubftance hitherto tri-
Pofitive < ed, except the back of a
i cat.
' Pofitive i Dry oiled fllk’ fulPhur>me-
X tals*
1 * W oollen cloth, quills, wood.
Negative -1 paper, fealing-wax,white-
wax, the human hand.
Pofitive -J Amber, air.
f
Negative - Diamond, the human hand.
p - • T Metals, filks, Ibadftone, lea-
° 1 U e - ther, hand, paper, baked
1. wood.
Negative Other finer furs.
Pofitive
L
Black filk, metals, black
cloth.
Negative 3 PaPer> hand> hares andwea-
egative | ^ ^
Pofitive - Sealing-wax.
1" Hares, weafels, and ferrets
Negative 1 ^K^adlW brafs, fil-
I. ver, iron, hand.
Pofitive - Metals.
1 ‘ Hares, weafels, and ferrets
Negative -' {kin, hand, leather, wook-
1. len, cloth, paper.
Pofitive >| Silk
Negative Flannel.
It appears from (3) that the power of producingElerfhified
eleflrical appearances may be communicated from an bodies,
excited electric to a condudlor. The more perfect the
conductor, the more eafily does it receive the eledric
power. Eledrics may alfo be made to receive this
power from excited eledrics, but it is communicated to
thefe with more difficulty than to condudors. When
any body, whether eledric or condudor, is made to ex¬
hibit eledrical phenomena, either by being excited,
or by communication, it is faid to be eleBnfied.
PART
64S ELECTRICITY. Parti.
PART I.
OF THE GENERAL PHENOMENA OF EXCITED ELECTRICITY.
%
TGeneral WHEN an ele&ric is once excited, it will retain
Phenomena.the eledlric power for a longer or fhorter time accord- ■*
' ing to its lituation and nature. If it communicates
freely with conductors, it wall lofe it fooner in propor¬
tion as thefe are more perfeft j but if it be infulated, it
will continue in an eleftrified ftate for a confiderable
10
Modes of
time.
Fri&ion.
Ele&rics may be excited in various modes j the
exciting e- greatefl; number of them by fridlion, as glafs, precious
.Juts. ^ones> fiih, fulphur, fealing-wax, amber, &c. j fome by
melting, and being allowed to cool, as fulphur, "wax j or
Amply by heating and cooling, as the tourmalin. We
fhall here give an account of the general appearances
exhibited by the principal electrics when excited in
thefe feveral modes.
Friction, as we have obferved, is the more ufual me¬
thod of exciting eleftrics. Thefe may be rubbed either
by other eledtrics, or by conductors, but in fome cafes
they are beft excited by being rubbed with the molt
perfedt conductors. Thus glafs rubbed with filk, ex¬
hibits figns of eleCtricity, but thefe are much ftronger
if the Aik be covered with fome metallic iubAance, as
an amalgam of zinc. Duft or moifture is found very
much to diminifh the excitability of eleCtrics \ but oil,
or any fat fubltance increafesit. The appearances Aiown
by eleCtrics excited by friCtion, differ fomewhat accord¬
ing to the nature of the eleCtric, and the fubltance em¬
ployed as a rubber *, we lhall defcribe the molt remark¬
able of them, as they will ferve hereafter to illuftrate
and explain the experiments which are to be introduced
in the following parts of this article.
Chap. I. Of the Phenomena produced hy excited glafs.
Phenomena Dr William Gilbert, a native of Colchelter in Ef-
from excit- pex^ an(j a phyfician in London, wTho publiAied in the
cu glafs. year 1600 a valuable treatife “ De Magnetef wTas the
Arlt, we believe, who obferved the eleCtrical property
of glafs when rubbed j but he difcovered little more
than that like amber it attracted and repelled light
bodies. He found fhat the molt tranfparent glafs was
* -Gilbert Athe belt electric *. In the beginning of the eighteenth
Magnetc, century. Mr Hawkefbee, to whom eleCtricity is in-
n. 2- debted for many improvements, made the Arft rational
M-Hawke-exPer“nen1;S 011 t^ie e^e<^:r^c Power con'
fbee’s expe-trived to Ax a hollow globe of glafs in a wooden frame,
riments. fo that it could be wdiirled round while he rubbed it by
applying his dry hand to the furface. He obferved
that when the air within the globe was confiderably
rarefied, a ftrong light appeared in the inude on apply¬
ing his hand to the globe, and when the air was reftor-
ed to its natural denfity, a light appeared alfo on the
outAde, appearing as if flicking to his Angers or other
bodies held near the globe.
Having exhaufted another globe of glafs, he oBferv-
■ed, that on bringing this near his excited globe, a
light appeared within the former, and became very
brilliant if the exhaufted globe was kept in motion, but
I
died away in a fhort time if it wTas ftiffered to remain at General
Phene mena*
He coated more than half of the inflde of a globe ' ~v ~ '
with fealing-wax of various thicknefs, and after exhduft-
ing the globe, he fet it in motion. On applying his
hand as a rubber, he wras furprifed to fee the exaCI
fhape of his hand appearing on the concave furface of
the wfax, and that even w'here the coating of wrax was
interpofed between his hand and the oppoAte Ade,
though the wax was in fome places an eighth of an
inch in thicknefs.
Pitch or common fulphur melted anfwered as wrell as
wax, but he could not produce thefe appearances by
uflng melted flowers of fulphur. When he employed
a very thick coating of common fulphur, he obferved
that there was a much greater light within the globe j
but he could not fo eaflly diftinguilh the figure of his
hands.
On admitting a fmall quantity of air into the globe,
the light diminiftied, and on the coating of fealing wxax
it entirely difappeared. While the globe continued ex¬
haufted, the coated part of it ftiowTed fome attraftion for
light bodies, but if there was no wax, the globe would * phxf,c0
not attrafl at all ; on admitting the air, the power oimechanical
attraction w7as greater on the coated than on the uncoat- experiments,
ed part. * P- 6S*
Glafs in any form is capable of excitation, but it is
more eafy, as well as more convenient, to employ a veffel
or plate of glafs than a folid rod or mafs of that fub-
ftance j and the thinner the veffel or plate is, the more
eaftly is it excited. When a tube, plate, or veffel of
glafs is excited, it is found that one Ade is ele&rifled
poAtively and the other negatively. Both fmooth and
rough glafs may be employed to produce electrical phe¬
nomena, but they require different rubbers. The beft
rubber for fmooth glafs is black oiled Aik fpread with an
amalgam of zinc, made in the proportion of four or Ave
parts of mercury to one of zinc. The beft rubber for
rough glafs is foft new7 flannel. The amalgam of zinc
may be moft conveniently made in the following man¬
ner. Place the zinc over the Are in an iron ladle •, and
when the ladle is red hot, put a fmall quantity of tal¬
low or fuet on the zinc, which will immediately melt.
It is beft not to allow the zinc to melt without the ad¬
dition of fome fatty matter, as tins metal is very eaflly
oxydated or calcined, and thus a great part of it would
be rendered unAt for the required purpofe } this in¬
convenience is prevented by the fat which covers the
furface of the melted metal, and protefts it from the
aftion of the air. When the zinc is melted, add the
mercury, previoufly heated to the degree of boiling wa¬
ter 5 ftir the mixture a Attle, and allow it to cool. Laft-
ly, rub it well in a glafs mortar, fo as to unite the
fat with it, which will prevent it from becoming hard
by keeping, and will allb preferve it longer from oxi¬
dation,
Mr Canton, who was the Arft perfon that employed
an amalgam to increafe the eftett of friCtion on glafs
tubes,
*5
Cavallo’s
tubes.
Chap. I. E L E C T R
General tubes, ufed an amalgam of two parts of mercury and one
Phenomena. 0f with the addition of a little chalk. Mr
' 'r~~l Wilcke found that a piece of woollen cloth fpread with
a little wax formed a very powerful rubber for fmooth
glafs. The bell rubber for rough glafs is foft new
flannel.
Mercurial It had been obferved by Mr Ha-wkelbee, that on
phofphorus. {baking mercury in a glafs veffel, in the dark, a con-
liderable light was produced, and that this was much
more remarkable when the air in the veflel wras con-
fiderably rarefied. He called the light which he con¬
ceived to be emitted from the mercury, mercurialphof-
phorus.
Mr Cavallo found that, by fluking mercury in a glafs
tube hermetically fealed, and in ■which the air was
pretty much rarefied, the tube was lenlibly eledlrified
on the outfide} but the ele&ricity produced was not con-
ftant, nor in proportion to the agitation. From this
obiervation he was led to make fome experiments, the
refults of which are very curious.
He prepared feveral tubes fuch as are reprefented at
experiments fig. 2. Plate CLXXXVII. about 31 inches long, and
with glafs fomewhat lefs than half an inch in diameter and about
one twentieth of an inch thick.
They were clofed at one end, and contained each
three fourths of an ounce of mercury, which being made
to boil, the air within the tube was rarefied and the o-
pen end was then hermetically fealed. Having made
the tube clean and a little warm, he caufed the mercury
to flow from the one end to the other, by gently eleva¬
ting and deprefling either end, alternately, while the
tube was held nearly in a horizontal pofition. The
tube wras thus rendered eleftrical, but fo that the end
where the mercury flood wus eledlrified pofitively (d)
and all the remaining part of the tube negatively. If
the mercury was made to flow from the pofitive end to
the negative, by elevating the former, the end to which
it flowed became pofitive, while the reft of the tube ac¬
quired a negative electricity j but if in elevating the
pofitive end where the mercury flood, that end were
not touched with the hand, it became negative only in a
flight degree, and if the mercury was made to flow back
to it, and again retire from it, ftill without touching it,
it became pofitive *, whereas by touching it while eleva¬
ting it, it was rendered ftrongly negative. The eledlric
power was always ftrongeft at the pofitive end. Ihe
eledlric power at either end was made much more ap¬
parent by coating each end for about two inches with
tin foil, as reprefented in the figure, fo that the tubes
would fometimes emit fparks on being brought near a
conductor. *
We have feen (6) that when an ele&ric is once
Vol. VII. Part II.
I C I T Y.
Cavallo s
£le£lricityf
vol. ii. p. 69.
16
Durability
of the elec¬
tricity of
glafs.
6.
excited, it retains the electric power for iome time. G'-rter
Glafs is one of the molt remarkable ele&rics in this P‘lclK^
refpeift. '
Mr Canton procured fome very thin glafs balls, about
an inch and a half in diameter, with flender tubular
Items of eight or nine inches in length. He electrified
thefe balls in the infide, or femi-pofitively, and then,
fealed the Items hermetically. On examining them af¬
ter fome time, he found that they Ihowed no ligns of
electricity; but on holding them at a fmall diftance from
the fire, they became ftrongly eledtrical, and ftill more,
fo as they cooled. On repeatedly heating them, he
found that the eledtric powrer diminilhed, but it wras not
impaired by keeping them for a week under water.
One of them which he had heated feVeral times be¬
fore immerfing it in water, and again feveral times after
lying for a wTeek in w7ater, ftill retained a conlider-
able degree of eledtric power at the end of above a
month ; and even at the end of fix years they had not
entirely loft it.
Mr Henley having eledtrified a fmall bottle, obferved
that it ftiowed figns of electricity feventy days after,
though it had flood all that time in a cupboard.
On the 5th February he excited a glafs cylinder j
and from that time till the 10th of March following,
various methods were employed to deltroy its eledtrici-
ty. Thefe always fucceeded at the time, and the cylin¬
der loft all figns of electricity ; but thefe figns returned
again without any frefli excitation, and on the 10th ot
March the cylinder ftill retained confiderable eledtric
power. The marks of eledtricity fometimes became
fironger or weaker, or even quite difappeared and re¬
turned without any evident caufe. The eledtricity was
generally ftrongeft when the wind was northerly, or
when it had returned after having been deftroyed by
flame j it was generally vveakeft when there was a fire
in the room where it was kept, or wdien the door was
left open. He repeated the excitation, but not al¬
ways with the fame fuccefs j for fome times the cylin¬
der would lofe all figns of eledtricity in a fortnight,
and at others in twelve hours, till it was again excited *. *
Tran/.
Crap. II. Of the Phenomena produced by excited
Silk.
SilK was firft difcovered to be an eledtric in the year
1729 by Mr Stephen Grey, while making experiments
with his friend Mr Wheeler. Thefe gentlemen at¬
tempted to condudt the eledtric power to a great di¬
ftance by means of filk lines, as Mr Grey had done be¬
fore by means of packthread j but they were di(’ap¬
pointed, as they found that the filk refufed to condudt,
4 N but
(d) The method of diftinguifhing between pofitive and negative eledtricity will be more fully explained here¬
after, as well as the modes in wdiich either may be produced at pleafure. But it may be proper here to Ihow a
Ample mode of diftinguilhing thefe two ftates of the eledtric powTer, which may be done by means of the inftrument
defcribed in (8). The eledtricity fliowm by excited polilhed glafs was faid to be pofitive j and it appeared that the
threads of the inftrument feparated when brought near an excited tube, as alfo when brought near excited fealing
wax, the eledtricity of which is negative. If, therefore, when the threads are made to diverge by excited glals,
they diverge ftill farther, or remain ftationary on being made to approach any other eledtrified body, the eledtricity
of this kft is pojitvve ; but if they collapfe, it is negative. Again if the threads, when made to diverge by excited
fealing wax, diverge ftill farther, or remain ftationary on being made to approach another eledtrified body, the
«ledtricity of this is negative j but if they collapfe, it \spofitive.
65° . ELECT
Fliaiomena l5Ut; )?jemc^ ral^er to retain the dearie pbwer j no
>. n^mena,'experiments of any confequence were however made on
this Jubilance, till I759> when Mr Symmer prefented to
the Royal Society a feries of obfervations which he had
made on lilk llockings.
He had been accuftomed to wear two pairs of filk
blockings j a black and a white. When thefe were put
off both together, no figns of ele£lricity appeared ; but
on pulling off the black ones from the white, he heard
a fnapping or crackling noife, and in the dark per¬
ceived fparks of fire between them. To produce this
and the following appearances in great perfection, it
was only neceffary to draw his hand feveral times
backv/ard and forward over his leg with the flocking
upon it.
Strong at- When the blockings were feparated and held at a di-
t raft ion fiance from each other, both of them appeared to be
Lon be-11 ' Eighty excited 5 the white flocking pofitively, and the
tween elec-blac1^ negatively. While they were kept at a dillance
tiified from each other, both of them appeared inflated to
Lockings, fuch a degree, that they exhibited the entire fhape of
the leg. When two black or two white flockings were
held in one hand, they would repel one another with
eonfiderable force, making an angle feefningly of 30 or
35 degrees. When a white and black flocking were
prefented to each other, they were mutually attracted ;
and if permitted, would rufli together with furprifing
violence. As they approached, the inflation gradually
iubfided, and their attradlion of foreign objects dimi-
niihed, but their attradlion of one another increafed ;
when they adlually met, they became flat, and joined
clofe together like as many folds of filk. When fepa¬
rated again, their eledlric virtue did not feem to be in
the lealt impaired for having once met •, and the fame
appearances would be exhibited by them for a con-
fiderable time. When the experiment was made with
two black ftockings in one hand, and two white ones
in the other, they were thrown into a flrange agitation,
owing to the attradlion between thofe of different co¬
lours, and the repulfion between tbofe of the fame co¬
lour. This mixture of attradlions and repulfions made
the flockings catch at each other at greater diftances
than otherwife they would have done, and afforded a
very curious fpedlacle.
When the ftockings were fuffered to meetj they
ftuck together with confiderable force. At firfl Mr
Symmer found they required from one to 1 2 ounces to
feparate them. Another time they raifed 17 ounces,
which was 20 times the weight of the flocking that
fupported them 5 and this in a diredlion parallel to its
furface. When one of the blockings was turned infide
out, and put within the other, it required 20 ounces to
feparate them j though at that time ten ounces were
futheient when applied externally. Getting the black
ftockings new dyed, and the white ones wafhed, and
whitened in the fames of fulphur, and then putting
them one within the other, with the rough fides toge¬
ther, it required three pounds three ounces to feparate
them. With ftockings of a more fubflantial make, the
cohebion was ftill greater. When the white flocking
Was put within the black one, fo that the outfide of
the white was contiguous to the infide of the black,
they raifed nine pounds wanting a few ounces ; and
‘when the two rough furfaces were contiguous, they-
raifed x 5 pounds one pennyweight and a half. Cut-
R I C I T Y. Part I.
ing oft the ends of the thread and the tufts of filk General
which had been left in the infide of the ftockings,Phenomena*
xvns found to be very unfavourable to thefe experi- '
merits.
Mr Symmer alfo obferved, that pieces of white and
black filk, when highly electrified, not only cohered
with each other, but would alfo adhere to bodies with
broad and even polifhed furfaces, though thefe bodies
were not electrified. Ibis he dilcovered accidentally j
having, without defign, thrown a flocking out of his
hand, which ftuck to the paper-hangings of the room.
He repeated the experiment, and found it would con¬
tinue hanging near an hour. Having ftuck up the
black and white ftockings in this manner, he came with
another pair highly eleClrified 5 and applying the white
to the black, and the black to the white, he carried
them off from the wall, each of them hanging to that
■which had been brought to it. The fame experi¬
ments held with the painted boards of the room, and
likewife with the looking-glafs, to the fmooth furface * Pkll.
of which both the white and the black filk appear- ?ranf yok
ed to adhere more tenacioufly than to either of thell' part u
former. * J^0’ig
Similar experiments, but with a greater variety ofExperi-
circumftances, were afterwards made by Mr Cigna of ments on
Turin, upon white and black ribbons. He took two ribbons by
white filk ribbons juft dried at the fire, and extended 1 r ClSna’
them upon a fmooth plain, whether a conducting or
eleCtric fubftance was a matter of indifference. He
then drew over them the fharp edge of an ivory ruler,
and found that both ribbons had acquired eleClricity
enough to adhere to the plain 5 though while they
coxitinued there, they fhowed no other fign of it.
When taken up feparately, they were both negatively
eleClrified, and would repel each other. In their fe-
paration, eleCtric fparks were perceived between them;
but when again put on the plain, or forced together,
no light was perceived without another friction. When
by the operation juft now mentioned they had acqui¬
red the negative eleClricity, if they were placed, not
upon the fmooth body on which they had been rub¬
bed, but on a rough conducting fubftance, they would,
on their feparation, fhow contrary eleClricities, which
would again difappear on their being joined together.
If they had been made to repel each other, and were
afterwards forced together, and placed on the rough
furface above mentioned, they would in a few minutes
be mutually attracted 5 the lowermoft being pofitively
and the uppermoft negatively eleClrified.
If the two white ribbons received their friCtion up¬
on the rough furface, they always acquired contrary
eleClricities. The upper one was negatively, and the
lower one pofitively eleClrified, in whatever manner
they were taken off. The fame change was inftanta-
neoufly produced by any pointed conductor. If two
ribbons, for inftance, were made to repel, and the
point of a needle drawn oppofite to one of them a-
long its whole length, they would immediately rulh
together.
The fame means which produced a change of elec¬
tricity in a ribbon already eleClrified, would commu¬
nicate eleClricity to one which had not as yet received
it} viz. laying the uneleCtrified ribbon upon a rough
furfaee, and putting the other upon it j or by holding
it parallel to an eleCtrified ribbon, and prefenting a
pointed
Chap. II. ELECT
General pointed conductor to it. He placed a ribbon that was
Phenomena. not qUite dry under another that was well dried at the
fire, upon a fmooth plain; and when he had given
them the ufual friction with his ruler, he found, that
in what manner foever they were removed from the
plain, the upper one was negatively and the lower
one pofitively eleftrified.—If both ribbons were black,
all thefe experiments fucceeded in the fame manner as
ytith the white. If, inftead of the ivory ruler, he
made ufe of any {kin, or a piece of fmooth glafs, the
event was the fame j but if he made ufe of a flick of
fulphur, the electricities were in all cafes the reverfe of
what they had beercbefore the ribbons were rubbed, ha¬
ving always acquired the pofitive eleCtricity. When
he rubbed them with paper either gilt or not gilt, the
refults were uncertain. When the ribbons were wrap¬
ped in paper gilt or not gilt, and the friction was made
upon the paper laid on the plain above mentioned, the
ribbons acquired both of them the negative eleCtrici-
ty. If the ribbons were one black and the other
white, whichever of them wras laid uppermoft, and in
whatever manner the friCtion was made, the black ge¬
nerally acquired the negative and the white the pofitive
eleCtricity.
He alfo obferved, that when the texture of the up¬
per piece of filk was loofe, yielding, and retiform like
that of a flocking, fo that it could move and be rub¬
bed againft the lower one, and the rubber was of fuch
a nature as could communicate but little eleCtricity to
glafs, the eleCtricity which the upper piece of filk ac¬
quired did not depend upon the rubber, but upon
the body on which it was laid. In this cafe, the black
was always negative and the white pofitive. But
when the filk was hard, rigid, and of a clofe tex¬
ture, and the rubber of fuch a nature as would have
imparted a great degree of eleCtricity to glafs, the
eleCtricity of the upper piece depended on the rub¬
ber. Thus, a white filk flocking rubbed with gilt
paper upon glafs became negatively, and the glafs po¬
fitively, eleCtrified. But if a piece of filk of a firmer
texture was laid upon a plate of glafs, it was akvmjs
eleCtrified pofitively, and the glafs negatively, if it was
rubbed with fulphur, and for the moft part if it was
rubbed with gilt paper.
If an eleCtrified ribbon was brought near an infulated
plate of lead, it was attracted, but very feebly. On
bringing the finger near the lead, a fpark w’as obferved
between them, the ribbon was vigoroufly attracted,
and both together fliowed no figns of eleCtricity. On
the feparation of the ribbon, they were again eleCtri¬
fied, and a fpark was perceived between the plate and
the finger.
When a number of ribbons of the fame colour were
laid upon a fmooth conducting fubflance, and the ruler
was drawn over them, he found, that when they were
taken up fingly, each of them gave fparks at the place
where it was feparated from the other, as did alfo the
laft one with the conductor ^ and all of them wrere ne¬
gatively eleCtrified. If they wTere all taken from the
plate together, they cohered in one mafs, w'hich was
negatively eleCtrified on both fides. If they were laid
upon the rough conductor, and then feparated fingly,
beginning wdth the lowTermoft, fparks appeared as be¬
fore, but all the ribbons were eleCtrified pofitively, ex¬
cept the uppermoft.—If they received the friCtion upon
R I C I T Y.
6.1
the rough conduCtor, and were all taken up at once, General
all the intermediate ribbons acquired the eleCtricity, ei-f‘‘enoineiia,‘
ther of the higheft or loweft, according as the fepa-
ration was begun with the higheft or the loweft. If
two ribbons wrere feparated from the bundle at the fame
time, they clung together, and in that ftate ftiowed no
fign of eleCtricity, as one ot them alone would have
done. When they were feparated, the outermoft one had
acquired an eleCtricity oppolite to that of the bundle, but
much weaker.
A number of ribbons were placed upon a plate of
metal to which eleCtricity was communicated by means
of a glafs globe, and a pointed conduCtor held to the
other fide of the ribbons. The confequence was, that
all of them became poffeffed of the eleCtricity oppo-
fite to that of the plate, or of the fame, accord¬
ing as they w'ere taken off j except the moft remote,
which always kept an eleCtricity oppofite to that of the
plate *. * Mem ef
the Acad-
Chap. III. Of the Phenomena produced by excited
Paper.
Turin, tor
1763.
1. When a Angle leaf of writing paper, after beingExperi-
warmed, is laid on a table, and rubbed brilkly with aments on
piece of caoutchouc, (elaftic gum or India rubber) itPaPer*
becomes itrongly eleCtrical } on attempting to remove
it from the table, it is found to adhere as if it were be-
fmeared with fome gluey fubftance j and if, before it is
quite feparated, it be fuffered to return to the table, it
will fly back with confiderabls force, and will adhere al-
moft as ftrongly as at firft.
2. On feparating it from the table immediately after
rubbing, it vrill be ftrongly attracted by the table or
any fubftance prefented to it, and remain in contaCt for
a confiderable time.
3. When the knuckle is prefented to the paper on its
being firft taken from the table, a fnapping noife is heard,
which is more perceptible if the knuckle be made to pafs
fucceflively over different parts of the paper. If this ex¬
periment is made in the dark, fparks will be feen to ac¬
company the fnapping noife.
4. On employing a double piece, or two pieces of
paper, thefe appearances will be increafed. On at¬
tempting to feparate the two pieces of paper, they are
found to adhere ftrongly together, and their feparation
is accompanied with a crackling noife, fimilar to that
produced by the application of the knuckle but not fo
loud. When quite feparated, on being brought again
within fome inches of each other they are ftrongly and
mutually attracted, and if, while feparated, one of them
be held between the other and fome contiguous fub¬
ftance, it wall be alternately attracted by that fubftance,
and the other piece, according as it is nearer the one or
the other.
5. Placing a piece of clean new flannel between the
paper and the table, or between the folds of the paper,
does not appear to diminifh the eleCtrical appearances
produced } but rubbing the paper with flannel produces
no remarkable figns of eleCtricity-.
6. It is not neceffary that the paper be rubbed on a
table to produce thefe appearances ; a book will anfwer
as well, but with this difference, that if the book be in
boards, the paper will produce no crackling when the
knuckle is applied to it 5 but when the paper is double,
4 N 2 the
/
652 ' ELECT
General the feparation of the folds will be attended with the
Phenomena. ;fame crackling as before ; whereas when the book is
bound in leather, a fingle fheet when rubbed will pro¬
duce the crackling on the application of the knuckle,
while the double piece will produce it only when its
folds are feparated. The adhefion of the paper to the
books is in both cafes much (lighter than its adhefion to
the table, and in the cafe of the book in boards it is
fcarcely perceptible.
7. White paper of all kinds feems capable of produ--
cing thefe appearances, when rubbed with caoutchouc 5
but blotting paper whether white or red produces them
in a very inferior degree, probably on account of the
weaknefs of its texture not allowing it to be rubbed with
fufficient force.
In general, the flouter the texture of the paper, the
ftronger will be the fparks and the attraftion.
8. Paper does not appear to retain its ele&ricity for
any great length of time ; in general, it ceafes to (how
any remarkable figns of eleftric power about 10 or 15
minutes after being excited.
9. Other fubftances befides caoutchauc may be em¬
ployed as rubbers , for the excitation of paper, efpe-
cially the dry hand, but none fucceed fo well as caout¬
chouc.
The ele&ric property of paper was firft difcovered by
Mr Grey. The paper employed by him was the kind
called white prejjing paper, which is of the fame nature
with card paper. Not only did this paper, when made
as hot as his fingers could bear, produce a light when
drawn brilkly through his fingers •, but when his fingers
were held near it, a light iffued from them alfo, attend-
* Phil. ed with a crackling noife *.
*Tranf. Air.
Chap. IV. Phenomena produced by the'Tourmalin.
20
Tourmalin
the lyncuri-
um of the
ancients.
2t
Experi¬
ments by
,/F.pinus;
22
by the due
de Noya;
Mr Canton.
24
Dr Prieft-
ley.
The electrical power of this (tone, fo far at lead as
refpefts its attraction of light bodies, was known to the
ancients ; as Theophraftus fpeaks of a (tone by him
called lyncurium, which agrees in all refpeCts with the
tourmalin, and which he fays attracted draws, adies,
and even fmall cuttings of iron and copper.
Nothing more feems to have been known of this done
tiil the year 1756, when M. ^Epimis made a fet of ex¬
periments on this done, which were printed in the Hi-
dory of the Academy of Sciences and Belles Lettres of
Berlin for that year.
In 1758, the due de Noya, in conjunction with M.
Daubenton and Adamfon made fome experiments on
the tourmalin, but they do not feem to have been fo ac¬
curate as thofe of M. Axpinus.
Soon after this done was introduced to the notice of
the Englifh, by Dr Heberden, who procured from Hol¬
land feveral, with which Aipinus’s experiments were
repeated by Mefirs Wilfon and Canton.
But the mod complete feries of experiments on the
tourmalin were made by Dr Priedley, and of thefe we
(hall here give a detailed account, as they comprife
nearly all that rs known on the fubjeCt.
R I c I T Y. Parti.
1. To afeertain the kind of eleCIricity produced, he General
had always at hand a dand of baked wood with four^henomena-
arms projecting from it. Three of thefe were of glafs, '■'■“"v-—--
having threads of fine filk as it comes from the worm
fadened to them, and at the end of each thread a fmall
piece of down. From the other arm hung a fine thread
about 9 or .10 inches long, while a brafs arm fufpend-
ed a pair of pith-balls. At the other extremity of
this arm, which was pointed, a jar could be placed, to
receive the eleCtricity, and by the repulfive power of
it keep the balls equally diverging with pofitive or ne¬
gative elearicity •, or fometimes he fufpended the balls
in an uninfulated date within the influence of large
charged jars: and ladly, he had always a fine thread of
trial at hand, by which he could difeover whether the
done was eleCtrical or not before he began his experi¬
ments (e).
2. Before he began any experiments on the done,
alfo, ha never failed to try how long the fine threads,
which he ufed as eleClrometers, would retain their vir¬
tue ; and found this to be various in various cafes.
When the threads would retain their eleftric virtue for
a few minutes, he preferred them ; but when this was
not the cafe, he had recourfe to the feathers, which
never failed to retain it for feveral hours. They might
be touched without any fenfible lofs of power, though
they received their virtue very (lowly. In the experi¬
ments now to be related, he made ufe of Dr Heber-
den’s large tourmalin, whofe convex fide became po¬
fitive and the flat fide negative in cooling ; and in all
of them, when the pofitive or negative fide of the tour¬
malin is mentioned, it is to be underdood that which
is pofitive or negative in cooling.
3. From Mr Wilcke’s experiments on the produc¬
tion of fpontaneous eleClricity, by melting one fub-
dance within another, he fird conjeftured that the
tourmalin might colleft its eleClricity from the neigh¬
bouring air: To determine which the following experi¬
ment was made. Part of a pane of glafs was laid on
the dandard bar of an excellent pyrometer, and upon
that glafs the tourmalin wras placed. This bar was
heated by a fpirit lamp, fo that the increafe or de-
creafe of heat in the tourmalin could thus be exaCtly
determined. In this fituation he obferved, that when¬
ever he examined the tourmalin, the glafs had acquired
an eleClricity contrary to that fide of the done which
lay upon it, and equally drong with it. If, for ex¬
ample, the flat fide of the done had been prefented to a
feather eleClrified pofitively, as the heat w^as increa-
fing, it would repel it at the dillance of about two inch¬
es, and the glafs wmuld attraCl it at the fame or a
greater didance j and when the heat w^as decreafing,
the (lone would attraCl, and the glafs repel it at the
didance of four or five inches. The cafe was the fame
whichever of the fides was prefented, as well as when
a (hilling wras fadened with fealing-wax upon the glafs;
the eleClricity both of the (hilling and glafs being al¬
ways oppofite to that of the done. When it came to
the turn, the eleClricky wras very quickly reverfed , fo
that
(e) Dr Priedley’s ipethod wdll be better underdood, after the reader has perufed Chap. I. III. and XIIL of
Part HI,
Chap.
 ^ iv. ELECT
General that in lefs than a minute the ele&ricity would be con-
phenornem.trary to what it was before. In tome cales, hm\-
  v  Cver viz where the convex fuiface of the tourmalin
was’laid upon the glafs or IhilUng, both of thefe be¬
came pofitive as well as the done This he fuppofed
to be owing to the done touching the furtace on which
it lay only in a few points, and that its electridt^was
collefted from the air j which fuppofition was vended :
for, getting a mould of Paris plaiter made for the tour-
malin, and heating it in the mould, fadened to a flip
of glafs, he always found the mould and glafs poffefled
of an eletdricity contrary to that of the done,, and e-
qually drong with it. During the time of cooling, the
mould feemed to be fometimes more drongly negative
than the done was pofitive ; for once, when the done
repelled the thread at the diltance of three inches, the
mould attracted it at the didance of near fix.
4. On fubdituting another tourmalin indead of the
piece of glafs; it was obferved, that when one of the
tourmalins was heated, both of them weie elechihed
as mu<;h as the tourmalin and glafs had been. If the
negative lide of a hot tourmalin was laid upon the ne¬
gative fide of a cold one, the latter became pofitive, as
would have been the cafe with a piece of glafs. On
heating both the tourmalins, though fadened together
by cement, they acquired the fame power that they
would have done in the open air.
5. As the tourmalins could not in this cafe touch in
a fufficient number of points, it was now thought pro¬
per to vary the experiment by cooling the tourmalin
in conta£l with fealing-wax, which w?ould fit it with
the utmod exa£tnefs. On turning the done, when cold,
out of its waxen cell, it was found pofitive, and the
wax negative} the electricity of the done being thus
contrary to wbat wrould have happened in the open air.
The other fide, which w7as not in contact w ith the
wax, acquired the fame eledtricity that it would have
done though the done had been heated in the open
air ) fo that both Tides now became pofitive. In like
manner the pofitive fide of the done, on being cooled
in wax, became negative.
6. On attempting to afeertain the date of the dif¬
ferent Tides of the tourmalin during the time it wras
heating in wax, many difficulties occurred. It was
found impoffible in thefe cafes to know exaflly when
the done begins to cool j befides, that in this me¬
thod of treatment it mud neceffarily be feme time in
the open air before it can be prefented to. the elec¬
trometer j and the electricity of the fides in heating
is by no means fo remarkable as in cooling. In the
experiments made with the tourmalin, wrhen its pofitive
fide was buried in wax, it was generally found nega¬
tive, though once or twice it feemed to be pofitive.
On cooling it in quickfilver contained in a china cup,
it always came out pofitive, and left the quickfilver
negative ; but this effeft could not be concluded to be
the confequence of applying the one to the other, be-
caufe it is almod impoflible to touch quickfilver with¬
out fome degree of friCHon, which never fails to make
both fides drongly pofitive though it be quite cold,
and efpecially if the done be dipped deep into it. At
lad, fuppofing that the done wTould not be apt to re¬
ceive any fridion by fimple prefiure againd the palm
of the hand, he was induced to make the experi¬
ment, and found it fully to aufwer his expectations *
r 1 c I T V. 6'53-
for thus, each fide of the done was affected in a
ner dire cl ly contrary to what would have happened m .-^.4
the open air.
7. Fadening the convex fide of the large tourmalin
to the end of a dick of fealing-wax, and prelfingAt
againd the palm of the hand, it acquired a drong ne¬
gative electricity, contrary to what would have hap¬
pened in the open air. I hus it continued till it had
acquired all the power it could receive by means of the
heat of the hand-, after which it began to decreafe,
though it continued feniibly negative to the very
lad.1 On allowing the done’to cool in the open air,
its negative power condantly increafed till it became
quite cold.
8. On heating the fame flat fide by means of a hot
poker held near it, and then jud touching it with the
palm of the hand when fo hot that it could not be borne
for any length of time, it became pofitive. Letting
it cool in the air it became negative, and on touch¬
ing it again with the hand it became pofitive 5 and thus;
it might be made alternately pofitive and negative for
a confiderable time. At lad, when it became To- cool
that the hand could bear it, it acquired a drong pofi¬
tive electricity, which continued till it came to the fame
degree of heat.
9. The wax was removed from the convex, and fal-
tened to the flat fide of the> done j in which circum-
dances it became weakly pofitive after receiving all the
heat the hand could give it. On letting it cool in the
open air it grew more drongly pofitive, and continued
fo till it was quite cold 5 and thus the fame fide became
pofitive both with heating and cooling.
10. On heating tire convex fide by means of a poker,
and prefling it againd the palm of the hand as foon as
it could be borne, it became pretty drongly negative j
though it is extremely difficult to procure any appear¬
ance of negative eleClricity from this fide ; and care:
mud be taken that a flight attraftion of the eleClrified*
feather, by a body not eleftrified, be not midaken for--
negative eleftricity.
11. On covering the tourmalin when hot with oil
and tallow,, no new appearances were produced $ nor
did the heating of it in boiling oil produce any other
effeft than leffening the eleftricity a little j and the7
event was the fame when the tourpialin was covered with
cement made of bees-wax and turpentine. On making
a fmall tourmalin very hot, and dropping melted feal¬
ing-wax upon it, fo as to cover it all over to the thick-
nefs of a crown piece, it was found to aft through this*
coating nearly, if not quite, as well as if it had been ex-
pofed to the open air. Thus a pretty decqstion may;
be made: for if a tourmalin be inclofed in a dick of wax,
the latter will feem to have acquired the properties, of
the done.
1 2. On letting the done cool in the vacuum of an
air-pump, its virtue feemed to be diminiflied about one
half, owing no doubt to the vacuum not being fuffi-
ciently perfefl.
J3. On fixing a thin piece of glafs oppofite and pa¬
rallel to the flat fide of the tourmalin, and about a quar¬
ter of an inch didance from it, in an exhauded re¬
ceiver, the glafs was fo llightly electrified, that it>
could not be didinguilhed whether it was pofitive or
negative.
13. On laying the done upon the dandard bar of.
IV LEG T B I C
ranIa tlie pyfOiT.eter, and communicating the heat to it by
means of a fpirit lamp, it was extremely difficult to
determine the nature of the eleftncity while the heat
was mcreafing to 70°; during which time the index of
the pyrometer moved about one 7200th part of an inch.
But if the Hone was taken off the bar, and an ele£tri-
fied thread or feather prefented to that fide which had
lam next it, the convex fide was always negative, and
the flat one pofitive.
14. To determine uffiat would be the effedl of keep¬
ing the tourmalin in the very fame degree of heaf for a
confiderable time together, it was laid upon the middle
of the bar, to wdnch heat wTas communicated by two
fpirit lamps, one at each extremity; and making the
index move 45 degrees, it was kept in the fame degree
for half an hour without the leaft fenlible variation 5 and
it was obferved, that the upper fide, which happened
to be the convex one, was always elearified in a fmall
degree, attrafting a fine thread at the diftance of about
a quarter of an inch. If in that time it was taken off
the bar, though ever fo quick, and an elearified feather
prefented to it, the flat fide, which lay upon the bar,
was negative, and the upper fide very flightly pofitive*
which appeared only by its not attraaing the feather.
On putting a piece of glafs between the ftone and ftan-
dard bar, keeping it likewife in the fame degree of heat,
and for the fame fpace of time as before, the refult was
the fame j the glafs was flightly elearified, and of a kind
oppofite to that of the ftone itfelf. To avoid the in¬
convenience of making one fide of the ftone hotter than
another, which neceffarily took place when it was heat¬
ed on the pyrometer, the following method was ufed.
By means of two rough places which happened to be
m the ftone, it was tied with a filk thread which
touched only the extreme edge of it j and thus being
perfeaiy infulated, it might be held at any diftance from
a candle, and heated to what degree was thought
neceffary j while, by twilling the firing, it was made
to prefent its fides alternately, and thus the heat was
rendered very equal in both. After being made in
this manner fo hot that the hand could fcarce bear it,
it was kept in that fituation for a quarter of an hour!
1. hen, with a bundle of fine thread held for fome time
before in the fame heat, the eledlricity which it had
acquired by heating was taken off, and it was found
to acquire very little, if any j whence appeared the
juftnefs of an obferyation of Mr Canton’s, that it is
the change of heat, and not the degree of it, that pro¬
duces the ele&ric property of this ftone.
15. On heating the ftone fuddenly, it may fometimes
be handled and preffed with the fingers feveral times
before any change takes place in the eleftricity which
it acquires by heating, though it begins to cool the
moment it is removed from the fire. In this cafe,
however, the ftone mull be heated only to a fmall de¬
gree. When the heat is three or four times as great
as is fufficiewt to change the eleclricity of the two fides,
the virtue of the ftone is the ftrongeft, and appears to
be fo when it is tried in the very neighbourhood of the
fire. In the very centre of the fire the ftone never
fails to cover itfelf with affies attra£led to it from every
quarter ; whence it acquired its name in Dutch.
16. The tourmalin often changes its eledlricity very
flowly j and that which it acquires in cooling never
fails to remain many houis upon it with very little di-
t
ITT. Parti.
minution. It is even poffible, that in fume cafes the General
eledlricity acquired by heating may be lb ftrong as to^enorntn8'
overpower that which is acquired by boiling j lb that '~*_v
both fides may ffiow the fame power in the whole ope¬
ration. “ I am very certain (fays the Dodlor), that in
my hands both the lides of Dr Heberden’s large tourma¬
lin have frequently been pofitive for feveral hours toge¬
ther, without any appearance of either of them having
been negative at all. At this time I generally heated
the tourmalin, by prefenting each fide alternately to a red
hoi poker, or a piece ol hot glafs, held at the diftance
of about half an inch, and fometimes I held it in the
focus of a burning mirror j but I have fince found the
lame appearance when I heated it in the middle of an
iron hoop made red hot. The ftone in all thefe cafes
was faftened by its edge to a Hick of fealing-wax. This
appearance I have oblerved to happen the ofteneft when
the iron hoop has been exceedingly hot, fo that the
outfide of the ftone mull have been heated fome time
before the infide ; and alfo I think there is the greateft
chance of producing this appearance, when the convex
fide of the ftone is made the hotter of the two. When
I heat the large tourmalin in this manner, I feldom fail,
to make both fides of the ftone pofitive till it be about
blood-warm. I then generally obferve a ragged part
of the flat fide towards one end of the ftone become
negative firft, and by degrees the reft of the flat fide ;
but very often one part of the flat fide will, in this
method of treatment, be llrongly pofitive half an hour
after the other part is become negative *. * Priefbi
° Mijl. Eletl.
Chap. V. Phenomena produced by excited fulphur. fedl. 12!'
Sulphur is one of thofe electrics which may be made Expen-
to exhibit eledrical appearances by being melted and ments on
fuffered to cool again. Dr Gilbert had Ihown that ful-fulPhu.r !,v
phur might be rendered electric by fridlion; but the firft W ikke,
perfon who demonftrated its excitability by melting,
was Mr Wilcke, of Roftoch in Lower Saxony, who
firft called this fpontaneous electricity.
He melted fome crude fulphur in an earthen veffel,
a»d left it to cool after placing the veffel on a condud-
ing fubftance. On taking out the fulphur when cool,
he found it llrongly eledrical, but this was not the
cafe when the veffel was placed on an eledric.
He then melted fulphur in glafs veffels, and found
that both the glafs and the fulphur became eledrical,
but the former acquired a pofitive, and the latter a ne¬
gative eledricity. When glafs veffels were employed, it
did not matter whether they were placed on eledrics
or condudors, except that the eledricity produced, was
ftronger in the former cafe, and Hill ftronger when the
glafs was coated with fome metallic fubftance. The
eledricity of the fulphur was not produced till it began
to contrad, and was the ftrongeft when the greateft de¬
gree of contradion bad taken place. The eledricity of
the glafs was always weakeft when that of the fulphur
was ftrongeft, and the former was the ftrongeft poffible
when the fulphur was lhaken out before it had begun
to contrad.
He found that when melted fulphur was poured into
veffels of rough glafs, or into hollowed cakes of fulphur,
no eledricity was produced.
Mr Wilcke alfo made experiments of the fame kind
with melted fealing-wax, and found that when this
Chap.
I Wilds
Difput.
26
iEpinus’s
experi¬
ments.
J JEpim
‘lentamen.
V. ELEC T
General was left to cOol in veffiils of fmootli glals or of wood,
Phenomena. tke fealing.W3X acquired a negative, and the glafs or
' ' wood a pofitive eleftricity \ but when it was cooled in
cups of fulphur, the fealing-wax became eleclrified pofi-
tively, and the fulphur negatively f.
^.pinus made fome experiments on melted fulphur
which he cooled in metal cups. On examining them
after the fulphur was cold, he found that while the
fulphur remained in the cups, neither of them fhowed
any figns of eledlricity •, but the moment they were fe-
parated, both appeared ftrongly ele&rieal. The marks
of eleftricity difappeared however on replacing the ful¬
phur in the cups, and returned on their being again fe-
parated. When feparated, the fulphur was eleftrified
pofitively, and the cups negatively j but if, before re¬
placing the fulphur in the cups, the electricity of either
was taken off, the fulphur and cups when together,
would fhow figns of that electricity that had not been
taken off
It muff be remarked here that though the eleCtricity of
the fulphur, fealing- wax, &c. in the above experiments
appears to be the confequence of their cooling after
being melted, it is in fa£t excited by a degree of fric¬
tion which thefe fubftances undergo by their contraction
while cooling in the cups, or by being touched with
the hand in making the experiment \ for it is found
that if they are cooled under circumftances that pre¬
vent all friCtion, a very fmall degree of which is fuffi-
cient to excite thefe bodies, no eleCtricity is produced.
This appears from experiments made by M. M. Van
Marum and Van Trooftwryck, for the purpofe of af-
certaining this point, an account of which is contained
in the 33d volume of Rozier’s Journal, to which we
mult refer our readers.
The durability of the eleCtric power in excited ful-
ot the elec- pftur is fo remarkable, that Mr Grey, from fome expe-
tric power riments which he made on this and limilar fubftances,
in iuiphur. was jecj t0 fUpp0fe it perpetual. In particular, he pour¬
ed melted tulphur into a conical drinking glafs, and
when it was cold he found, that on taking off the glafs
the fulphur never failed to attraCt light bodies, and
that in every ftate of the atmofpherej and in fair weather
the glafs would alfo attraCt.
Mr Henly, who repeated Mr Grey’s experiments,
fays, he has never known the fulphur fail of Ihowing
iigns of eleCtricity on the removal of the glafs.
Although it be true that fulphur, as well as roftn,
fealing-wax, amber, and filk, retain the eleCtric power
for a conftderable time, this is, however, continually
diminiftiing, and at length difappears altogether.
Other fubftances, as well as ftilphur and fealing-wax,
become eleCtrical by cooling after being melted. Mr
Henly obferved that chocolate, when firft from the
mill, as it cools in the tin pans into which it is re¬
ceived, becomes ftrongly eleCtrical, and retains this pro¬
perty for fome time after being taken out of the pans,
but lofes it by handling. If melted again, and left to
cool as before, its eleClricity returns, though in a lefs
degree •, and thus it may be renewed once or twice, but
ftill in a much fmaller degree than before. But if be¬
fore pouring it into the pan, it be well mixed with a
little olive oil, it becomes again ftrongly eleClrical.
When a ftick of fea4ing-wax is broken acrofs, each
R I c I T Y.
the one pofitively and the other negative-
6c ^
General
Phenomena.
27
Durability
28
EleCtricity
of choco¬
late.
29
Sealing-
wax excit-
bgbbrokcn.P^ece becomes ekClrified at the extremities that were
contiguous
ty- . . _ v _
When wood that is hard and pretty dry, is cut or ,0
ftiaved, the {havings are rendered eleClrical. This fa Cl EleCtricity
was firft obferved by Mr William WTilfon, who, from of vvoodj
a number of experiments, draws the following conclu-fhavinSs'
fions.
From thefe experiments it appears, that when very
dry wood is feraped with a piece of window glafs, the
{havings are always politively eleClrilied. And if chip¬
ped with a knife, the chips are pofttively eleClrified if
the wood is hot, the edge of the knife not very {harp,
and negatively eledrified if the wood is quite cold.
But if the edge of the knife is very keen, the chips
will be negatively eleCtrified whether the wood is hot
or cold.
The greateft number of trials was made with the in-
fulated knife, which was always eleClrified contrarily
to the chips ; but the furface of the wood where the
chips were cut from was very feldom eleClrified, and
when it was it, was always but weakly fo, and of the
fame denomination as that of the weakeft of the other
two. Mr Wilfon repeatedly found that if a piece of dry
and warm wood is fuddenly fplit afunder, the two fur-
faces which were contiguous are eleClrified, one fide
pofitive and the other negative.
Powders, either of eleClrics or conductors, are ren-EleCtricity
dered eleClrical by dropping them on an infulated me- of powders
tallic plate.
The method, as deferibed by Mr Cavallo, is as fol¬
lows :
“ Infulate a metal plate upon an eleCtric ftand, fuch
as a wine glafs, and conned with it a cork-ball electro¬
meter ; then the powder required to be tried, being
held in a fpoon, or other thing, at about fix inches
above the plate, is to be let fall gradually upon it. In
this manner the eleCtricity acquired by the powder, be¬
ing communicated to the metal plate, and to the elec¬
trometer, is rendered manifeft by the divergence of the
threads 5 and its quality may be afeertained in the ufuaj
manner ; to be hereafter deferibed.
“ It muft be obferved, that if the powder is of a con¬
ducting nature, like the amalgam of metals, fand, &c,
it muft be held in fome eleCtric fubltance, as a glafs
phial, a plate of fealing-wax, or the like. Sometimes
the fpoon that holds the powder may be infulated, in
which cafe, after the experiment, the fpoon will be
found poffeffed of an eleCtricity contrary to that of
the powder.
“ In performing thefe experiments, care muft be
taken to render the powders, and whatever they are
held in, as free from moifture as pofiible ; fometimes
it being neceffary to make them very warm, otherwife
the experiment is apt to fail. The following are the
particulars which have been obferved with this method,
which, however, are neither numerous, nor often re¬
peated ; but they may fuffice to excite the curioftty of
thofe perfons, who have leifure and the opportunity of
repeating them more at large and in a greater variety.
“ Powder of rofin, whether it be let fall from paper,
glafs, or a metal fpoon, eleCtrifies the plate ftrongly
negative ) the fpoon, if infulated, remaining ftrongly
politive. Flower of fulphur produces the fame effeCt,
but in a little lefs degree. Pounded glafs, let fall
from
6$6
£ledlrical
Apparatus.
31 .
Ele&ricity
Ihown by
vapour.
33.'
Galvanic
ckAricity.
ELECT
)rom a piece of paper, made dry and warm, elearifies
; the plate negatively, but not in fo ftrong a degree as
rofm. If it be let fall from a brafs cup, it eleftrifies
the plate pofitively, but in a very fmall degree.
“ Steel-filings let fall either from a glafs phial or
paper, ele&rify the plate negatively; but brafs-filings,
treated in the fame manner, eleffrify the plate pofitive-
-V. I he amalgam of tin-foil and mercury, gunpowder,
or very fine emery, eledrify the plate negatively, when
they are let fall upon it from a glafs phial. *£)uick-
filver, from a glafs phial, electrifies the plate pofitrvely.
. “ Soo,; from the chimney, or the alhes of common
pit-coal mixed with fmall cinders, electrify the plate
negatively, when let fall from a piece of paper.”
M. Volta difcovered, that when water and feme
other fluids are reduced to a ftate of vapour, by
throwing the fluid on fome lighted coals placed in an
infulated crucible, the vapour fhews figns of pofitive
electricity, while the coals it is leaving are negatively
eledtrified j and hence it is concluded, that all fluids in
the adt of evaporation become eledtrical, the vapour be¬
ing eledtrified pofitively, and the body which it is
leaving negatively; and again, that when vapour be¬
comes condenfed into a fluid, it becomes negatively
eledtrifled, leaving the bodies with which it was laft in
contadt in a ftate of negative electricity.
Some condudtors arranged in certain w-ays will pro¬
duce eledtrical appearances without fridtion, or com¬
munication with any eledtric eiycept the air.
Thusjf a plate of zinc, a plate of filver, or of cop¬
per, and a piece of woollen cloth moiftened with fome
* .1 C I T Y. patt II.
faline foliation, as of muriat of ammonia, be arranged in Electrical
the order we have mentioned one above another^ they Apparatus,
w ill manifelt figns of eledtricity, which will be the "’V—^
ftronger in proportion as the fets of metal and cloth are
more numerous.
The fame appearances 17111 be more manifelt if the
metallic plates joined together be fixed in a trough at
fmall diltances, while the intermediate fpaces are filled
with the faline folution.
As the appearances produced by condudtors arranged
m this way are of a peculiar nature, we fhall not treat
of .them in this article, but refer the confideration of
them till wre come to Galvanism.
Under the fame article will alio be confidered the
eledtrical phenomena which are produced by certain
animals, as the torpedo, &c.
The glafs tube and the dry hand, mentioned in (i)f
conftitute the moil fimple elefirical apparatus of which
the efl'ential parts are the ele&ric and'the rubber. But
for the purpofe of experiment it is neceffary to have the
eledtric of coniiderable fize, furnifhed with fome pro¬
per fubftance which can always perform the office of a
rubber, and fo firmly fixed as not to be eafily difturbed
from its fituation in the courfe of our experiment. We
fhall then have what is called an electrical machine.
As much of the fuccefs of eledtrical experiments de¬
pends on the proper conftrudtion and management of
the machine and its attendant apparatus, we fhall here
give a pretty full account of the ufual apparatus be¬
fore we proceed in explaining the principles of the
fcience.
PART IL
OF ELECTRICAL APPARATUS.
Chap. I. Of the Conf ruction of Electrical Ma¬
chines.
3i
Gonftruc- \\ K fhall firft lay down the general principles on
tHcal ma20* W^C^- t^e con^ru<^on °f an eledtrical machine and the
chines. d adjufling of its feveral parts depends *, and lhall after¬
wards defcribe fome of the more important machines
which are now in ufe.
I he principal parts in an eledtrical machine are the
electric, the engine by which it is to be fet in motion,
3S the rubber, and the prime conductor.
EJedtric. Several fubftances have, at various times been em¬
ployed as eledtric s, as fulphur (r), roftn, polifhed glafs,
and rough glafs; and they have been ufed of various
form globes, fpheroids, cylinders, &c. The reafon of
this variety of form feems to be that experience had not
fhown what form was the molt convenient j but the
different fubftances were employed for the purpofe of
producing a pofitive or negative eledtricity as the natute
of the experiment or the fancy of the operator might re¬
quire.
But as this purpofe is better anfwered by infulating
the rubber, or allowing it to communicate freely with
condudtors, polifhed glafs is almoft the only fubitance
at prefent employed as the eledtric of a machine.
Globes of glafs are fometimes ufed, but the molt con¬
venient forms are cylinders and plates. ,
The moft convenient fize for globes Is from nine to Cylinder,
twelve inches diameter. They are made with one
neck, which is cemented to a ftrong brafs cap, in order
to adapt them to a proper frame. The moft conveni¬
ent cement for holding together the parts of eledtrical
apparatus is made by melting together, over a gentle
fire, two parts of rofm, two of bees-wax, and one of
powdered red ochre. This cement is much better than r. r .
r 1 • r i Lenient tot
roim alone, as it ierves the purpoies or mlulation ele&rical
equally well, and is much lefs brittle. Globes were apparatus.
formerly
(f) Tne firft perfon who conftrudted any thing like an eledtrical machine w as Otto Guericke, burgomafter of
Magdebourg, who lived in the latter end of the 17th century. He formed-a globe of fulphur by melting this
fubftance. a gl°be, which he then broke away from it, little imagining that the glafs itfelf would have an-
fwereci his purpofe much better. Vid, Experiment a Magdeburgica,
2
Chap.
plates of
glafs.
39
I. ELECT
Elcdlrical formerly much more ufed than at prefent j their great
Apparatus- advantage appears to be, that by making the electric
11 v revolve on an axis nearly perpendicular, the upper part
- is more completely infulated ; but one great diiadvan-
tage attends this motion, namely, that as the preilure is
applied at a diftance from the fulcrum, it in time
-o loofens the adhefion of the ftrongeft cement.
Plates of glafs are much in falhion on the continent ;
and they feem to attribute to this form much of the
wonderful power of their machines, as of that at Haar¬
lem, to be hereafter mentioned. Perhaps the greateft
advantage of plates is that the fri&ion may be applied
to both furfaces at once j but it may be doubted,
whether this be not an imaginary advantage, and this
form is attended with feveral material inconveniences •,
as, i ft, Plates cannot bear any great preflure of the
rubber ; 2d, They cannot be inlulated without very
complicated machinery ; 3d, As they are fixed by the
centre, and the fri£tion is applied towards the circum¬
ference, if much force be employed, there will be great
danger of breaking (the plate, or at leaft of loofening
it, and thus difturbing the equability of its motions j
and, qthly, They are much more expenfive than any
other form, and hence, as they are much expofed to
injury, the replacing of them becomes a very ferious
object.
The ingenious Mr Cuthbertfon has contrived to ob¬
viate fome of thefe difadvantages, and his plate ma¬
chines are very conveniently managed, as well as very
powerftil in their effeft.
Cylinders to On the whole, the cylindrical form feems preferable
be prefer- to any other, and this is now almoft univerfally em¬
ployed. The cylinders fhould be blown kas light as
poffible, confiftently with fufticient ftrength, and their
furface ftiould be as equable and free from knots or pro¬
tuberances as may be j for thefe not only render the
cylinder more liable to be broken, but prevent the lilk
of the rubber from being clofely applied to every part
of the furface. To avoid thefe inequalities, the cylin¬
der fhould be blown at the time when the glafs is in
the moft complete ftate of fufion, and this is found to
be the cafe, when the pot is about half emptied, which
happens at the London glafs-houfes on Wednefdays and
Thurfdays.
The cylinders are ufually made of the beft flint-glafs,
but it is not determined which is the beft kind. In
fize they vary from eight inches long and four in dia¬
meter to two feet long and one foot in diameter, which
is perhaps as large as they can be conveniently blown.
Very fmall cylinders are, however, of little ufe, and it
may be doubted whether the diameter fhould not be
greater in proportion to their length than what is above
afligned. It is of great confequence that the cylinders
fhould have been properly annealed, or that they
fhould be brought very gradually from the temperature
of the glafs-houfe to that of the external air ; as when
they have been too fuddenly cooled, they are apt to
fly in pieces in the a£t of whirling, to the great annoy¬
ance both of the experimenter and the fpeftators.
Cylinders are made with two necks ; and the open¬
ings of thefe ftiould be fo wide as to admit the hand to
clean the inner furface of the glafs, which is fometimes
fullied by condenfed vapour. Thefe necks are ce¬
mented as above directed, to caps of brafs, which are
VOL. VII. Part II.
red.
P, I C I T Y. 657
much fuperior to wooden caps, as they may be made EleftrLat
much more fmooth and equal. 1 'y .
Brafs caps have been objedled to on account of the
conducing power of the metal; but this objeftion is
abfurd, as the infulation depends on the diltance be¬
tween the cap and the cufhion, which, as will be men¬
tioned prefently, fhould be as great as poflible. Indeed
wood, if ever fo well dried, is but a very imperfedl in-
fulator, and the hardeft can never be fo completely po-
liftied as a metallic fubftance. I he brafs cap fhould be
compofed of two parts •, one a ring to be cemented round
the neck of the cylinder, with an {iperture fufficient to
admit of the introduction of the hand within the glafs,
and with a furface as extenfive as poflible, that the ad¬
hefion of the cement may be the more complete ; the
other a head or lid of brafs completely polifhed, to be
fcrewed into the ring, and with an orifice into which
the winch or the pin on which the other end of the
cylinder is fupported may be fcrewed. 4®
It has been thought of advantage to line the infide Coating of
of the glafs with fome electric fubftance, as wax, rofin, ^
&c.: this has been thought by fome to increafe the ex¬
citability of the glafs. It feems afcertained, however,
that if fuch a coating does not make a good cylinder
better, it at leaft often improves a bad one. The com-
pofition moft approved for coating globes or cylinders
is formed of four parts of Venice turpentine, one part
of rofin, and one of bees-wax, melted together and kept
boiling over a gentle fire for about two hours, fre¬
quently ftirring it. When a velfel is to be coated with
this compofition, a fufficient quantity of it, broken into
fmall pieces, is to be put within the globe or cylinder,
which is then held to the fire to melt the compofition j
and by cpnftantly turning it round, the coating is to be
fpread equally over the lurface to about the thicknefs
of a fixpence. In doing this, care muft be taken to
heat the glafs very gradually and equally, otherwife it
is liable to be broken during the operation. 41
The eleftric is fet in motion either by a Ample Mear.s of
winch, or by means of multiplying wheels. The form-^^'lS
er, as being more fimple, and confequently lefs liable
to produce diforder in the motion of the machine, is
generally to be preferred. The handle of the winch is
lometimes made of glafs, but this is unneceffary ; for
the glafs does not ftiorten the interval, which is moft;
favourable to the difperfion of the electric power.
Multiplying wheels w^ere much more common form¬
erly than at prefent. The ufual method of employing
thefe is, to fix a wdieel on one fide of the frame of the
machine, -which is turned by a winch, and has a groove
round its circumference.
Upon the brafs cap of the neck of the glafs globe*
or one of the necks of the cylinder, is fixed a pulley,
whofe diameter is about the third or fourth part of the
diameter of the wrheel; then a firing or itrap is put
over the wheel, and the pulley ; and by thefe means*
when the winch is turned, the globe or cylinder makes
three or four revolutions for one revolution of the
wheel. The principal inconvenience attending this
conftrudlion, is, that the firing is fometiroes fo very
flack, that the machine cannot wrork. To remedy
this, the w'heel fhould be made moveable with refpe£t
to the eleftric, fo that, by means of a fcrew, it may be
fixed at the proper diftance ; or elfe the pulley fhould
4 O have
658 elect
Elertrical have feverai grooves of different radiufes on its circum-
Apparatus. ference>
The chief advantage of multiplying wheels, is that
the arm of the operator is lefs fatigued by turning the
machine, when thefe are employed, than when a limple
■winch is ufed } and as by theie the motion of the elec¬
tric is rendered quicker, it is fuppofed by feme that its
electric power is proportionally increafed.
In feme machines, inltead of the pulley or firing de-
feribed above, there are ufed a wheel and pinion, or a
wheel and an endlefs ferew. This machinery requires
confiderable nicety in its conftru&ion, is apt to pro¬
duce an unpleafant rattling, and unlefs frequently oiled
the conllant friction of the parts again!! each other
ibon wears them away, fo as to render the motion very
uniteady.
Rubber. . Ihe rubber (g), by which the eleblric is to be ex¬
cited, confilts of two parts. One part is a cufhion,
which is uiually made of a piece of red bafil fkin, fluff¬
ed with hair or flannel. The cufhion is either fixed
to a piece of wood well rounded at the edges, and
faftened to a fupport of glafs, or feme other infulatmg
fubftance $ or where two conductors are employed, it is
fixed to one of thefe. The cufhion fhould be made as
hard as the bottom of an ordinary hair-chair, and
Ihculd be fo adapted to the furface of the cylinder, as
to prefs equally on it in every part. For this pwrpofe
it is generally provided with a fpring, by which
means it may be the better adapted to any inequalities
of the furface of the glafs 5 in the ufual conftruefion of
the cufhion the fpring is placed without, but Mr Jones,
inflrument-maker in London made, what he confiders
as a great improvement on the mode of placing it.
1 his confifls in a fpring placed within the rubber it-
ielf j the aCtion of which is found to be better fuited
for adapting the rubber to the inequalities of the glafs,
than that placed entirely without the rubber. It con-
fifts of a piece of flexible iron or brafs, reprefented
edgewde by A, fig. 3. •, and it is evident that it aCts in
a much more parallel and uniform manner than the
former, which is conflantly changing the preffure of
the line of contaCl betwixt the rubber and cylinder
while it paifes from the under to the upper fide, thus
rendering the effeCt inconflant and uncertain.
The length of the cufhion fhould not exceed one-
third of the length of the cylinder ; for if it were
longer, the infulation would be much lefs complete,
fince one end of the conductor (when the rubber is
fixed to a conductor) mult ahvays be nearer to the
hand by two or three inches than the cufhion.
The other part of the rubber confifls of a piece of
black Perfian lilk as broad as the length of the cufhion,
and reaching from it over nearly one half of the cylin¬
der. It fhould be fewed upon a ware, bent at both
ends, and thefe ends are adapted to holes made on the
upper edge of the wood to which the cufhion is fallen-
v c 1 T Y- Partir,
ed j or it may be glued to the edge of the cufhion : but Eledtricaf
t te former mode of fixing it is to be preferred, as it Apparatus,
can then be eafily removed. Si.,-V-—. "*
I he rubber fhould be infulated in the moil perfeCt
manner ; as, when infulation is not required, it may be
eafily taken off by a chain or w ire hung upon it, and
thus communicate with the earth or with any unelec¬
trified body j but where there is no contrivance for in¬
ti atmg the rubber, it is impoffible to perform many of
the molt curious experiments. In fliort, to conltruct
the rubber properly, it mull be made in fuch a manner,
that the fide it touches in whirling may be as perfect a
conductor as it can be made, in order to fupply ele&ri-
uty as quick as poflible j and the oppofite part fhould
be as perfect a non-condu£tor as pofhble, in order that
none of the elettric power accumulated upon the glafs
may return back to the rubber j which has been found
to be the cafe when the rubber w^as not made in a pro¬
per manner (h).
Of late, a confiderable improvement in the rubber Wolff?,
has been made by M. Wolff, of Hanover. The con- provement
itiuchon and advantage of his rubbers, as applied to rul>~—
plate machine fimilar to that of Van Marum, of which ^er*
an account will be given by and by, is thus deferibed
by the author in a paper in Gilbert’s Annalen der P/iy-
frek for 1802, and tranflated in Nicholfon’s Journal, for
february 1804, from which we have copied them.
The four rubbers are made of dry walnut wood foak-
ed in amber varnilh, and are inches long, 14- broad,
and a little more than one quarter of an inch thick.
1 he metallic plate that communicates with the leather
covered with amalgam, is only 14 inch broad, and
is fixed externally to the centre of the piece of wood.
The rubbers are preffed towards the glafs by means of
a fpring. They are covered with a piece of thick
woollen, upon which is a piece of fine neat’s leather.
A’V.er the leather is faftened to the wood, it is wetted,
and preffed between twm boards, where it is kept till it
is again dry. thus it is rendered very fiat, and its
edge very fharp, and all its parts will apply to the fur¬
face of the glafs. Ihis piece of leather is covered with
another a little broader, the rough furface of which is
towards the glafs, and its low^er edge on the fide to¬
wards which the plate moves 5 and its lower edge on
the other fide from which the plate moves, being like-
wife very fharp. The piece of filk is applied with ac¬
curacy to this leather. Before it is faftened on, it is
heated, and befmeared firft with butter of cacao, then
vvith a large quantity of Kienmayer’s amalgam (1) j
and after it is faltened on, it is compreffed in conjunc¬
tion with the wrood, or prefied fhongly againft the
machine. The leather is next covered with amber var-
niih, amalgam is fpread over this, and after the varnifh
is dry, it is fmoothed with a burnifher. This is re¬
peated feverai times. I he whole being very drv, and
the rubber being preffed fo as to touch the glafs in all
points.
(g For a long time the only rubber employed was the dry hand of the experimenter, till the middle of the
to ih century, when M. Wmckler, profeflor at Leipfic, introduced the cufhion. It was long after this, however
^e ore electricians could be perfuaded that any rubber wras better than the clean dry human hand. Vid. Prieftlev^s
riijt. part 1. fee. 7. J J
(H) The improvement of the filk flap was firft introduced by Dr Nooth. Vide Phil. Tranf. vol. Ixiii.
i i; He adds to this amalgam as much filver, as the mercury can diffolve in conjunction with the zinc.
Chap.
I. E L E C T
Eledlrical points, tlic Icatlier coated with amalgam (k) is covered
Apparatus. a p[ece of fine white paper, as long as the leather,
' v ' and half an inch broader, fo as to cover the Team that
fallens the fills to the leather $ and the paper is faften-
ed to the wood above or below, accordingly as it is
on the afcending or defcending fide of the plate.
Dry paper is known to be capable of acquiring a
high Hate of electricity, which induced me to try this
fubftance as an immediate rubber. The following are
the advantages, that by my experiments, repeated and
varied in a great number of ways, I have found paper
employed as a rubber to poffefs over every other known
fubllance.
1. The glafs is not rendered dull by the friftion, as
happens at length, and by frequent ufing, when it is
in immediate contact with the amalgaftn.
2. By the immediate contact of the amalgam, the
glafs-frequently contracts Itreaks here and there, that
occafion a circulation of the fluid. I. his cannot take
place in the conftrudlion 1 propofe.
3. Neither the glafs ‘nor the filk can be foiled. It
it well known, that the cleannefs of the glafs, as well
as of the rubber and the whole machine in general, is
of importance in producing an intenfe degree of elec¬
tricity. It is true, that it has been propofed to apply
the amalgam to the glafs in Head of the rubbers 5 but
the greater effect, that feems to be produced by this
laft method, is only apparent, and confifts entirely in
the circulation of the fluid on the glafs, rvhile far from
exciting or accumulating more of the fluid, this procels
and the circulation difperfe it.
4. The amalgam on the leather does not require to
be frequently renewed. The duff of the amalgam,
that is depofited on the edges of the paper, is injurious
-only when accumulated there in fufficient quantity to be
conveyed to the glafs, from which however it may eafily
be removed.
5. The return and paffage of fparks to the rubbers
are rendered more difficult, as the paper fufficiently
covers the borders of the rubbers, that are turned to¬
ward the axis.
6. In my conftruclion the rubbers may be larger
than in the ufual wTay, and in reality they are larger in
proportion in my machine than in Van Marum’s. No
{park paffes the axis, unlefs the air be very damp. I
am perfuaded, that, by adopting my conftrudlion, the
rubbers of a plate of 32 inches, fuch as Van Marum’s
is, may be eleven inches inffead of nine, in which
cafe there wrould Hill be two inches for the diameter of
the piece of wood that faftens the plate to the axis, and
three inches for the diftance from this piece to the rub¬
bers •, which I think would be fufficient in thefe cir-
cumftances j and the friction being on a larger furface
of the plate, the effedl muff naturally be much great¬
er. I ftiall try this alteration of the rubbers on large
plates of Bohemian glafs, as wrell as on Englifh eylin-
R 1 C I T Y.
t>59
ders of 18 inches diameter, and 21 inches long. I he kwctncal
reiult 1 have already obtained with a Imall cylindei L "J, ^ r >
gives me reafon to hope much more complete ruccels
with a large one.
7. With my rubbers the fri&ion may be rendered
much greater, than with thofe the amalgam of which
is in immediate contafl with the glafs, and foils it •, be-
fides, the plate turns with an uniform friction.
8. The activity of the machine is extraordinarily in-
creafed by this conftrudtion. The greater freedom
with which the plate moves, even under a greater pref-
fure, and the paper’s preventing the glafs from being
foiled, w7ould be fufficient to produce this effect •, even
if the greater preffure alone did not occafion a more
powerful efteft than can be obtained from common
machines. _ p • ^ 00
The laft Part a machine wffiich we are to deferibe^'™^
is the prime conduSor.
This is a cylindrical tube, ufuaily made of brafs,
copper or tinned iron, the two firlt of which are much
the beft, as they admit of more nicety in the conftruc-
tion, efpecially of being better poliffied. When re¬
quired very large, the cylinder may be made of paffe-
board covered with tin- foil or gold-leaf. It is of great
confequence that the conductor be made perfectly free
from points or edges, and where holes are made in
it, as is commonly done, for the purpofe of experiment,
thefe fliould have their edges perfe£tly fmooth and even.
The cylinder is clofed at both ends by fpherical lids or
covers, made fo as to fit with the greateft accuracy,
but fo as to be taken off, if requifite. Thefe ends are
fometimes made larger than the reft of the cylinder j
but this is unneceffary, and it is much better that
they fliould form with it one fmooth and uniform fur-
face. In fome machines the conductor is placed at
right angles to the glafs cylinder, but it is now ufually
placed parallel to it. At the end or fide oppofite the
glafs, are fixed a row of metallic points, for receiving
the ele&ric power •, thefe are generally either fixed im-
moveably in the fide or end of the condudtor, or are
fixed along a feparate piece of ftrong brafs wire, which
is made to ffiut into two holes in the conductor, fo that
the points can be removed at pleafure. Mr Reid con¬
trived to fix them to rings turning on an axis, the ends
of which were forced into holes made in the conduc¬
tor, fo that the points refted on the glafs, with which
they were thus in perpetual contact, without difturbing
its motion. It is certainly of great advantage to have
the points as near the glafs as poffible, but this mode of
fixing them is attended with the inconvenience of mul¬
tiplying the protuberances on the furface of the con¬
dudtor.
The fize of the condudtor is of fome confoquence j
in general its length ffiould equal that of the giafs cy¬
linder including its necks, and its diameter ffiould be
about one«-third of that of the cylinder. It fliould be
4 O 2 infulated
(k) The amalgam mentioned by M. Wolff is formed of two parts of mercury, one part olpurified •zinc, and
one of pewter. The zinc and pewter are melted together, and, before the mixture is quite cool, the mercury
is added. The whole is then poured into a clofe box, lhaken for fome time and left to cool on a marble flab.
When nearly cold, it is reduced to powder in a glafs or earthen mortar, taking care not to triturate it fo long as
to make it turn gray. The Baron de Kienmayer, the author of this amalgam, has given a particular account of
its preparation and ufes in the 33d vol. of Rozier’s Journal, p. 96. q. v.
66o
ELEC T
Electrical mfulatcd by being fixed on a pillar of glafs covered
* lls.’ w'ith fealing-wax. For this purpofe, the fealing-wax
may be diflblved in alcohol (fpirit of wine), and thus
applied to the glafs pillar j but it is better to heat the
glafs gradually, and then rub it over with the fealing-
wax till it is covered to a fufficient thicknefs. Where
there are two conductors, one of them lupports the rub¬
ber, and is called the negative conductor; this is not
furnilhed with points : the other, which is what we
have juft defcribed, is placed oppofite and parallel, on
the other fide of the glafs, and is called the pojitive
conduftor (l).
It is proper to have feveral brafs balls furnifhed with
ftalks, fome ftraight, and others curved, wdiich may
be fitted into the holes in the furface of the condu&or.
I he balls Ihould be of various fizes, and fhould be
made to fcmv \ipon the ends of the ftalks, fome of
which Ihould be terminated by points. It is convenient
alfo that fome of the ftalks be made with a joint, fo
that the ball or point can be placed in any pofition.
paratns at Ele&rical machines Ihould be fumiftied with one or
tached to * m°te chains, by which, when infulation is not requir¬
ed, either of the conductors may be made to communi¬
cate with the table or with the floor.
There is alfo attached to the electrical machine, a
ftool with four glafs legs or feet, for the purpofe of
infulating various bodies in the courfe of experiment,
and hence called the infulating fool. This ftool ftiould
be made either of baked wood or thick glafs, and
ftiould be fufficiently large to fupport an ordinary chair,
or at leaft fo large that a perfon can eafily ftand on it.
Chap. II. Defcription of fome particular EleBrical
Machines.
45
Other ap-
the ma
chine.
46
Dr Prieft-
ley’s ma¬
chine.
4-
The firft machine wdiich we fhall defcribe is one in¬
vented by Dr Prieftley, w^hich has been confidered by
fome as fo ingenious, that it has been called a univer-
fal eleBrical machine.
It is thus defcribed by Dr Prieftley in his hiftory.
The frame confifts of two ftrong boards of maho¬
gany. of the fame length, parallel to one another, about
four inches afunder ; and the lower is an inch on each
fide broader than the upper. In the upper board is a
groove, reaching almoft its wdiole length. One of the
pillars, wThich are of baked wTood, is immoveable, being
let through the upper board, and firmly fixed in the
lower, while the other pillar Aides in the groove above
mentioned, in order to receive globes or cylinders of
different fizes ; but it is only wanted wrhen an axis is
ufed. Both the pillars are perforated W7ith holes at
equal diftances, from the top^to the bottom by means
of w’hich globes may be mounted higher or lower ac¬
cording to their fize ; and they are tall to admit the
ufe of two or more globes at a time, one above the
qther. Four of a moderate fize may be ufed, if two
be fixed on one axis 5 and the wheel has feveral grooves
for that purpofe.
R I C I T Y. Part II.
it a globe wuth only one neck be ufed, a brafs arm Eledtrical
with an open focket, is neceffary to fupport the axis be- apparatus.
yond the pulley 5 and this part is alfo contrived to be' 7 1
put higher or low'er, together wdth the brafs focket in
which the axis turns. The axis is made to come quite
through the pillar, that it may be turned by another
handle, without the wheel, if the operator chufes.
The frame being fcrewed to the table, may be placed
nearer to, or farther from the wheel, as the length of
the firing requires, in different ftates of weather. The
wheel is fixed in a frame by itfelf, by which it may
have a fituation with refped to the pulley, and be
turned to one fide, fo as to prevent the firing from cut¬
ting itfelf. The hinder part of this frame is fupported
by a foot of its own.
The rubber confifts of a hollow piece of copper lin¬
ed with horfe hair, and covered with a bafil Ikin. It
is fupported by a focket, which receives the cylindrical
axis of a round and flat piece of baked wood, the op¬
pofite part of which is inferted into the focket of a bunt
fteel fpring. Thefe parts are eafily feparated ; fo that
the rubber, or piece of wood that ferves to infulate it,
may be changed at pleafure. The fpring admits of a
twofold alteration of pofition. It may be either flip¬
ped along the groove or moved in a contrary diredion ;
fo as to give it every definable pofition with refped to
the globe or cylinder ; and it is befides furniftied with
a fcrew, which makes it prefs harder or lighter, as the
operator chufes.
The prime condudor is a hollow veffel of polilhed
copper, in the form of a pear, fupported by a pillar,
and a firm bafis of baked wood, and it receives its fire
by means of a long arched wire, or rod of very foft
brafs, eafily bent into any lhape, and raifed higher or
lower, as the globe requires 5 and it is terminated by
an open ring, in which are hung fome Jharp-pointed
wires playing lightly on the globe when it is in mo¬
tion. The body of it is furnilhed with holes and fockets,
for the infertion of metallic rods, to convey the fire
wherever it is wanted, and for many other purpofes
convenient in a courfe of eledrical experiments. The
condudor is by this means fteady, and yet may be
eafily put into any fituation. It colleds the fire per-
fedly well, and (what is of the greateft confequence
though but little attended to) retains it equally every¬
where.
When pofitive eledrity is wanted, a wire or chain,
as is reprefented in the figure, conneds the rubber with
the table, or the floor. When negative eledricity is
wanted, that wire is conneded with another condudor,
fuch as is reprefented at fig. 5. while the condudor at
fig. 4. is conneded by another wire or chain with the
table. If the rubber be made tolerably free from
points, the negative power will be as ftrong as the po¬
fitive.
In ftiort, the capital advantages of this machine
are, that glafs veflels, or any other eledric body, of
any fize or form, may be ufed, with one neck or two
necks
(l) M..Boze, profeffor at Wittemburg, firft employed a prime conduBor ; his condudor was a tube of iron
or tin, which1 he infulated at firft by its being held by a man Handing on cakes of rofin, and afterwards by
fufpending it by filken lines, horizontally before the globe. For a long time a gun-barrel was employed as a
prime condudor.
Chap.
Ik The
The
IT. ELECT
Electrical necks at plealure ) and even feveral of them at the
Apparatus fame time if required. All the effential parts of the
"v machine, the globe, the frame, the wheel, the rubber,
and condu&or, are quite feparate $ and the pofition of
them to one another may be varied in every manner
poffible. The rubber has a complete infulation, by
which means the operator may command either the
pofitive or negative power, and may change them in
an inftant. The conductor is fteady and eafily en¬
larged, by rods infcrted into the holes, with which it is
furnifhed, or by the conjundtion of other conductors in
order to give larger fparks, &c. The wheel may be
ufed or not at pleafure ; fo that the operator may either
fit or ftand to his work, as he pleafes; and he may
with the utmoft eafe both manage the wheel and his
apparatus.
Plate This machine is figured in Plate CLXXXVII. fig. 4.
clxxxvii where
a a. Reprefent the two boards of the frame.
b, One of the pillars.
c, The brafs arm with the open focket.
d, The axis on which the globe turns.
e, The frame to which the wheel is fixed.
f, The rubber •, g, The piece of baked wood 5
fteel fpring •, i. The fcrew.
b, The prime condu&or ; /, The rod or wire ;
points.
n, The wire for connecting the rubber with the table.
Machine by Next to Dr Prieftley’s machine, tve (hall defcribe
Dr Ingen- one which was invented by Dr Ingenhoufz, in which
houfz. a pjate 0f giaps ;s employed initead of a globe or cylin-
der.
There is a circular plate of glafs, about a foot in di¬
ameter, perforated in the centre by an iron axis, upon
which it is turned vertically by means of a winch. It
has four cufhions, each above two inches long, which
are fituated at the oppofite ends of its vertical diameter.
It moves in a frame compofed of a bottom board about
a foot fquare, or a foot long and about fix inches broad,
upon which are raifed two other fmaller boards, paral¬
lel to each other, and fattened together at the top by
a fmall wooden crofs bar. By thefe upright boards,
the axis of the plate is fupported, and to them the
cuthions are fattened. When the machine is ufed,. the
bottom of the frame is fattened to the table by an iron
crank. The condu&or in this machine is made of hol¬
low brafs; and is furniihed with branches extending
from its extremities, and approaching very near the
circumference of the plate.
An improvement on this machine is thus defcrib-
ed by Mr Walker in his Le&ures on Familiar Philo-
fophy.
Plate “ It is made of a round plate of thick looking-glafs,
CEXXXVII (fi^, 6. Plate CLXXXVII.) This plate turns on an axis
a, Supported by the mahogany frame c cc, by the han¬
dle r. The rubbers are of red leather fluffed with curl¬
ed hair, and nailed to thin flips of wood, (It!, one on
each fide of the glafs, and made to prefs die glafs very
clofe by the fcrews xx to thefe rubbers are attached
oiled filk curtains, z 2, on both rides of the glafs. The
condu&or, w w w, is of brafs and fixed to the frame,
c cc, by the glafs fupporter y, which infulates the con¬
du&or w, and terminates in the two knobs, s s ; into
tkefe knobs are fcrewed fmall cylinders of brafs, with
R I c I T Y. 661
a number of points that nearly touch the glafs, and re- Electrical
ceive the ele&ric matter from it ; they cannot be feen
in the drawing, being behind the curtains. For excit-
ing pofitive ele&ricity in all kinds of weather and fitua- •(• Walter t
tions, this is the molt powerful and convenient ma- Lett. yol. ii.
chine ever yet invented”f. 2d edit.
A very powerful machine, in which plates of glafs w?c^;ne ;n
are employed, is that in Teyler’s mufeum at Haarlem, Xeyler’s
conftru&ed by Mr John Cuthbertfon. It confifts ofmufeumat
two circular plates of glafs, each 65 inches in diame-Haarlem,
ter, and made to turn upon the fame horizontal axis,
at the diftance of 7F inches from one another. Thele
plates are exerted by eight rubbers, each 154-inches
long. Both fides of the plates are covered with a re-
linous fubftance to the diftance of \ 6i inches from the
centre, both to render the plates ftronger, and likewile
to prevent any of the ele&ricity being carried off by
the axis. The prime condu&or confifts of feveral
pieces, and is fupported by three glafs pillars 57 inches
in length. The plates are made of French glafs, as
this is found bell next to the Englilh flint which could
not be proenred of fufficient fize. The condu&or is
divided into branches which enter between the plates,
but colle& the fluid by means of points only from one
fide of the plate. The force of two men is required to
work this machine ; but when it is required to be
put in a&ion for any length of time, four are necef-
fary.
By this machine Van Marum made his experiments
on metals, &c. which will be mentioned hereafter.
Within thefe few years, Dr Van Marum has con-Van Ma.
ftru&ed a new machine, of fmaller dimenfions, but oflurn’s neW1
much greater proportional power than the preceding. tnac"'ne'
It is thus deferibed in Nicholfon’s Journal. Fig. 75.
PI. CXC. exhibits a perfpe&ive view of the machine,
and fig. 76, 77, 78, 79, a fe&ion, exclufive of the
cufhions. In the view it may be obferved that the
cufhions are each feparately infulated upon pillars of
glafs, and are applied nearly in the dire&ion of the ho¬
rizontal diameter of the plate, inftead of the vertical
diameter as heretofore. The ball diametrically oppo¬
fite to the handle is the prime condu&or, and the femi-
circular piece with two cylindrical ends ferves, in the
pofition of the drawing, to receive the eie&ricity from
the plate. By the happy contrivance of altering the
pofition of this femicircular branch from vertical to
nearly horizontal, the cylindrical ends may be placed
in conta& with the cufhions, and the prime condu&or
inftantly exhibits negative ele&ricity. But as it is ne-
ceffary that the cufhions fhould communicate with
the ground when the pofitive power is wanted,
and that they fliould be infulated when the negative
powrer is required, there is another femicircular branch
applied to the oppofite fide of the plate nearly at right
angles to the firft. That is to fay, when pofitive elec¬
tricity is wanted, this fecond branch denoted by I, I in
the fe&ion fig. 76. is placed nearly - horizontal, and
forms a communication from the cufhions to the ground
through a metallic rod from K behind the mahogany
pillar which fupports the axis ; but when, on the con¬
trary, the negative power is wanted, and the branch
from the prime condu&or is placed in conta& with the
cufhions, this other branch from the axis is put into the
vertical fituation, and carries off the ele&ricity emitted
from the plate of glafs.
The
Plate
CXC.
6(52 E Tj ^
Eicdlrical The axis of the plate B //, fig. 76. is fupported by a
TP'le column A ix4^E   r . .
Apparatus./; i . 1 f, r ’ 7&- 15 mpported by a
 , Angle column A, which for that purpofe is provided
With a bearmg-pifece K, on which two brafs collar-pie.
ces DID, reprefented more at large and in face in fig.
7«. are fixed, and carry the axis itfelf. The whole of
nflD6, 1Sf t0,°ne l6th of its real dimenfions,
u lefs contrafted _ by the fhrinking of the paper after
printing ; to obviate which, it may be remarked that
the diameter of the plate is 31 Engliih inches. The
axis has a counterpoife O, of lead, to prevent too great
inchon m the collar D heard! the handle. The arc
o. the conductor EE, which carries the two fmall re¬
ceiving conductors FF, is fixed to the axis G, which
turns m the ball H. On the other fide of the plate is
feen the other arc I I, of brafs wire, half an inch in
diameter, fixed to the extremity of the bearing-piece
K, in that it may be turned in the fame manner as the
arc J1D. I he two receiving conductors FF are fix in-
ches long and two and a half inches in diameter.
I he double line P represents a copper tube termina-
ting m a ball g. It moves like a radius upon the item
R or the ball S, which being ferewed into the conduc-
tor H, ferves to confine the arm P in any pofition
which may be required. The diameter of the ball S is
on y tuo inches, which, together with certain other
• th s rounded Parts of this apparatus, may ferve to fhow
1 r nT6 r T 6 elearicity from this machine is
Ids difpofed to efcape than if it had proceeded from a
t yhnder. ^ I he diifipation of eleCtricity along the glafs
iupports is prevented by a kind of cap T, of mahoga¬
ny, which affords an eleCtrical well or cavity under¬
neath and like wife effectually covers the metallic caps
into which the glafs is cemented. The lower extremi¬
ty ol the cap is guarded in the fame manner by a hol¬
low piece or ring V, of mahogany, which covers the
metallic focket into which the glafs is cemented. The
- wee glafs pillars are fet in Hiding-pieces, as marked
fong1 ^ P atf°rm °f 75, which are nine inches
The rubbers of this machine differ in no effential
particular from thofe deferibed by the inventor in the
Journal de Phyfique for February 1791 ; and the ap¬
paratus for applying them is deferibed in the fame work
for April 1789 Fig. 77. reprefents a feCtion of this
.judicious piece of mechaniim feen from above, and one-
lourth ol the real fize. A metallic Hiding -piece £ b is fiid-
c arcorrePPondent face, on the ball Z, which is one
°t thole fixed on the top of the glafs pillars near the
circumference of the glafs plate in fig. 75. To this is
affixed the piece dd, which terminates in two hinges
JyG Jhat allow the fprings e e to move in the plane of
the horizon. Ihe pieces reprefent the wood-work
or the culhions attached to the extremities of the fprings
by the hinges hThe fprings are regulated by the
oolt and ferew ? 7. The two cufiiions are thus made to
appjy to the plate equally through their whole length •
the actions on the oppofite Hides of the plate are accu-
1 ately the fame ; and the play of the hinges g g, pre-
vents the prate from being endangered by any drain in
the direction of its axis. It is certain that, before this
adequate provifion was made to fecure thofe effential
requifites, it was impracticable to apply the cufhions to
a plate with the fame fafety and effed as to cylinders
which poffefs much itrength from their figure. An in’
genious workman will probably find little difficulty in
Z
1 ,C 1 T D. Pari II.
conhruftmg thefe rubbers from this defeription and EleDrical
-rung; but the moft precife information refpeCtinn-Apparatus.
every circumftance and dimenfions is to be found in the ^
letters above quoted.
The inner extremities of the cuffiions are defended
y t e plates of gum-lac YY, which cover the three
ncles or edges, and prevent their attracting the elec-
trie power from the ends of the receiving conductor.
he part of the axis which moves between the col¬
lars ,s made of fteek The middle of the non-conduc¬
ing part of the axis is a cylinder of walnut-tree a a aa,
baked until its infulatmg power is equal to that of glafs,
and then ioaked in amber varniffi, while the wood ftill
whlT eXtremitles of this cylinder,
which are of a lefs diameter, are forced, by ftrong
blows, with a mallet, into the flout brafs caps £ and r
m which they are retained by three iron ferews dd.
I je cylinder a a, and the brafs caps, are covered with
a ayer of gum-lac ceee, to preferve the infukting
fate of the wooden cylinder more perfectly, and to
prevent the cap b from throwing daffies to the rubbers.
I he bottom of the cap b is ferewed home on the cap¬
ped extremity of the Heel axis b. The bafe of the cap
which is four inches in diameter, terminates in an
axis one inch thick, and two in length ; the extremity
of winch is formed into a ferew. The glafs plate is
put on this projecting part, and fecured in its place by
a nut of box-wood, forced home by a key, applied in
the holes z 1. Two rings of felt are applied on each ■
me of the glafs, to defend its furface from the contaCt
of the wood and the metal; and the central hole in
the glals, which is two inches in diameter, contains a
ring of box-wood, which prevents its immediate appli>
cation to the axis.
As it is neceffary that the axis G ffiould be parallel
to the axis of the plate, in order that the conduftors
. * move parallel to the plate itfelf, the pillar M
is rendered adjuffable by three bearing ferews RR at
the bottom which re-ad againfi the itrong central
crew 1, and this is drawn downwards by its nut The
conductors FF are alfo adjuflable by the Hiding-pieces
*7•’ naiU • biuding-fcrews w w, which alfo afford an
adjultment to bring the axis of each fmall conductor
parallel to the face of the glafs plate. A fimilar ad-
juitment may be obferved at the extremities of the
arc II.
79' reprefents a feCtion of the moving part of
the branch II, one-half of its real fize. A brafs plate
is ferewed to the face of the capital K by three iron
icrews /3. I'o this is icrewed another ring 2 2, which
affords a groove for the moveable ring y y, into which
the arms II are fixed. This is accordingly applied in its
Place before the ring ^ is fixed.
The wooden part of the rubbers GG, fig. 77 is
covered with thin plates of iron, excepting the furface
neared to the glafs. The intention of this is to main¬
tain a more perfeCt communication between the rubbed
part of the cuffiion and the earth or negative conductor
as the cafe may be.
The plates of gum-lac YY, are applied to the rub¬
bers, each by means of a thin plate of brafs, to which
they are affixed by heat. There are two wires rivetted
in the plates, which are thruft into correfpondent holes
in the wooden part of the cuffiion.
The mahogany column A ends in a fquare £ £ upon
which
Chap. II. E L E C T
Electrical which the piece K is fitted and firmly applied, by means
Apparatus-0f the fcrew and nut exhibited in the feftion. f
The following defcription of a ufeful machine is ta-
J-JL.lu!.ken from Mr Cavallo> who confiders it as one of the
vol. i. p. 84. moft complete with which he is acquainted.
The frame of this machine confiils of the bottom
board ABC, which when the machine is to be ufed,
is faftened to the table by two iron clamps, one of which
appears in the figure near C. Upon the bottom board
are perpendicularly raifed two ilrong wooden pillars
KL, and AH, which fupport the cylinder, and the
wheel. From one of the brafs caps of the cylinder
FF, an axle of Heel proceeds, which paffes quite through
a hole in the pillar KL, and has on this fide of the
pillar a pulley I, fixed upon its fquare extremity. Up¬
on the circumference of this pulley there are three or
four grooves, in order to fuit the variable length of the
Bring b, wdiich goes round one of them, and round
the groove of the wheel D. The other cap of the cy¬
linder has a fmall cavity, wdiich fits the conical extre¬
mity of a ftrong fcrew, that proceeds from the pillar
H. The w'heel D, which is moved by the handle E,
turns round a flrong axle, proceeding from alinoil the
middle part of the pillar KL.
The rubber G of this machine is on each end twTo or
three inches fhorter than the cylinder (i. e. the cylinder
exclufive of the necks), and it is made to rub about
one-tenth part of the cylinder’s circumference, or ra¬
ther lefs ; it confifts of a thin quilted culhion of filk,
Huffed wdth hair, and faffened by filk firings upon a
piece of wood, which is properly adapted to the furface
of the cylinder. And to the lower extremity of the
culhion, or rather of the piece of wood to which the
culhion is tied, a piece of leather is faftened, which is
turned over the culhion, i. e. Hands between it and the
furface of the -cylinder, and to the extremity of which
a piece of filk or oiled filk is faftened, wdaich covers
almoft all the upper part of the cylinder. Upon this
leather, which reaches from the lower to almoft the up¬
per extremity of the culhion, fome of the amalgam is to
be worked, fo as to be forced as much as pofiible into
its fubftance : if mofaic gold is to be tried, then the
leather Ihould be newr, and whereon no other amalgam
has been put. This rubber is fupported by two fprings,
fere wed to its back, -and from which it may be eafily
unferewed, when occafion requires it. The two fprings
proceed from the wTooden cap of a ftrong glafs pillar,
perpendicular to the bottom board of the machine.
This pillar has a fquare wooden balls, that Hides in two
grooves in the bottom board ABC, upon w'hich it is
faftened by a fcrew7. In this manner the glafs pillar1
may be faftened at any required diftance, and in confe-
quence the rubber may be made to prefs harder or
lighter upon the cylinder. The rubber in this manner
is perfectly infulated j and, wdien infulation is not re¬
quired, a chain with a fmall hook may be hanged to
it, fo as to have a regular communication with the
piece of leather $ the chain then falling upon the table,
renders the rubber uninfulated.
Fig. 7. reprefents the prime conductor AB belong¬
ing to this machine. This is of hollow brafs, and is
fupported by two glafs pillars varnilhed, that by tw'O
brafs fockets are fixed in the board CC. This conduc¬
tor receives the electric powder through the points of the
it I C I T Y. 663
colledtor L, which are fet at about half an inch diltance Ele&rical
from the farface of the cylinder of the machine. Apparatus.^
If the handle E of the w'heel, be turned (and on ac¬
count of the rubber it Ihould be turned alw7ays in the
direction of the letters a b c) this machine Handing in
the fituation that is reprefented in the figure, will give
pofitive electricity, i. e. the prime conductor will be
electrified pofitively. But if a negative electricity be
required, then the chain muft be removed from the rub¬
ber and hung to the prime conductor ; for in this cafe
the eleCtricity of the prime conductor will be communi¬
cated to the ground, and the rubber remaining infula¬
ted, will appear ftrongly negative. Another conduc¬
tor, equal to the conductor AB, may be connected
wdth the infulated rubber, and then the operator may
obtain as ftrong negative electricity from this, as he
can pofitive from the conduCtor AB. 50
prefently deferibed, will anfwer for moft purpofes of
eleCtrical experiment better than any other.
The cylinder in Mr Nairne’s machine is about twelve
inches long and feven in diameter ; it turns upon two
wrooden pieces cemented on the top of two ftrong glafs
pillars, BB. Thefe pillars are made fait into the bot¬
tom board of the machine, which is faftened to the ta¬
ble by means of a crank. There are grooves made in
the under part of the bottom of the crank, through
wThich the pieces FE Hide. On thefe pieces the pillars
Hand by w hich the two conductors are fupported; and
in order to place thefe conductors nearer to the cylin¬
der, or remove them farther from it, the pieces on
which they Hand are moveable imvards or outwrards,
and may be fixed by the two fcrew nuts LL. The
rubber is faftened to the conduCtor R j and confifts of
a culhion of leather Huffed, having a piece of filk glued
to its under part. This laft being turned over the fur¬
face of the culhion, and thus inteipofed between it and
the glafs, goes over the cylinder, and almoit touches
the pointed wires w'hich are fixed on the other conduc¬
tors. The conductors are of tin covered with black
lacquer, each of them containing a large coated glafs
jar, and likewife a fmaller one, or a coated tube, which
are vifible when the caps NN are removed. To each
conduCtor is fixed a knob O, for the occafional fufpen-
fion of a chain to produce pofitive or negative elec¬
tricity. The part of the winch C, which aCts as a le¬
ver in turning the cylinder, is of glafs. Thus every
part of the machine is infulated, the cylinder itfelf and
its brafs caps not excepted. And to this the inventor
has adapted fome flexible condufting joints, a difeharg-
ing eleCtrometer, and other utenfils necefi’ary for the
praCtice of medical eleCtricity.
A modification of this, machine is reprefented at
fig. 9.
a, the handle of the cylinder.
b, the negative, and c, the pofitive conduCtor.
d, the filk flap of the rubber.
51’
Mr Reid’s portable machine, as improved by Mr Mr Reid’s
Lane, is the lalt wdiich wre lhall deferibe, and is repre-Porta^e
fented at fig. 10. A is the glafs cylinder, moved ver-p.achine'
tically by means of the pulley at the lower end of the 8’
axis,-
The next machine which wTe fliall mention is one m- MrNairne
vented by Mr Nairne, wdiich is chiefly employed for niachme.
medical purpofes ; but a modification of wdiich, to be *
6<54 ELECT
EWTrical axis. This pulley is turned by a large wheel B, which
> ^ ^ lies parallel to the table. There are three pulleys of
different dimenfions marked in the figure; one of which
revolves four times for every revolution of the large
wheel B. The condu&or C, is furniihed with points
to colleft the fluid, and is fcrewed to the wire of a
coated jar D, which Hands in a focket between the cy¬
linder and the wheel. This figure alfo fliews how
Mr Lane’s ele&rometer, to be afterwards defcribed,
may be adapted to this machine.
A great many other machines have been defcribed
in the Philofophical Tranfaftions, Journal de Phyfique,
and in various books on eleflricity; but thofe of which
we have given an account are the moft material.
Chap. III. General direElions for uftng the EleBri-
cal Machine.
•5* It is of the greateft confequence that the machine,
as well as the table on wdiich it Hands, and every thing
in its neighbourhood, be perfe<ffly free from dull ; it is
therefore neceffary to begin by wiping every part of
the machine, &c. with a clean, dry, foft linen cloth.
If the weather is not warm and dry, it will be proper
alfo to place the machine for fome time before the fire,
that it may be perfeftly free from moiflure. The cy¬
linder if ufed lately and not cleaned, may have con-
tradted fpots of dirt or greafe ; ih wiiich cafe it muff
be rubbed with a foft rag dipped in fpirit of wine. In
fhort, very much depends on the machine being quite
free from dirt and moiHure.
•53 The conductors are now to be fixed in a proper fitua-
tion, fo that the rubber of the negative condudtor may
prefs clofely to the cylinder on one fide, and the points
of the pofitive condudtor may approach on the other as
near to it as pofiible, without touching. Then while
the cylinder is made Jo revolve, the amalgam is to be
applied to it, where it is not covered with the filk j
this is beH done by means of a piece of leather to
which the amalgam has been previoufly faHened, which
is a better method than by fpreading it on the rubber.
As the amalgam is liable to oxidation from expofure to
the air, it is proper to fcrape the furface of it before it
is applied to the cylinder) and if any old amalgam has
been left on the cufhion of the rubber, this fliould alfo
be fcraped before ufing the new.
54 After having made thefe arrangements, on whirling
the cylinder in contaft with the rubber, without bring¬
ing any conducting body near the former, or infulating
the latter, wre will perceive in the dark a flream of fire
iffuing from the place of contaCt between the rubber
and the cylinder, and adapting itfelf to the form of the
cylinder, fo as to involve it in a blue flame mixed with
bright fparks ) the whole making a very perceptible
whizzing and (napping noife. If the finger is brought
near the cylinder in this lituation, the flame and fparks
will leave the cylinder and Hrike the finger) and this
phenomenon will continue as long as the globe con¬
tinues to be whirled round.
On applying the prime conduftor, the light wrill va
nilh, and be perceptible only upon the points prefented
to it by the cylinder ) but if the finger is now brought
near the conduCtor, a very fmart fpark will Hrike it,
nnd that at a greater or fmaller diHance, according to
' the Hrength of the machine. This fpark, when the
l
55
56
R I C I T Y. Part II.
eleCtricity is not very Hrong,. appears like a ffraight Electrical
line of fire j but if the machine aCts very powerfully, Apparatus
it will put on the appearance of zig-zag lightning,v——v——^
throwing out other fparks from the corners, and flrike
with fuch force as to give confiderable pain to thofe
who receive it.
If thefe appearances do not take place, or if they
take place only in a flight degree, foon after the apply¬
ing the amalgam, fpread a little oil on the palm of
your hand, and let it flightly touch the cylinder as it
moves round j in general this is inflantly followed by a
copious emiflion of fparks, numerous torrents of wrhich
will now pafs from the edge of the filk to the knuckles.
Sometimes, however, after ufing all thefe precautions,
the machine does not aCt w^ell, and in this cafe the rub¬
ber fliould be examined, to fee if fomething is not
wrong there. The rubber fliould be removed from the
glafs pillar or the negative conduftor, to which it is
faflened, by’taking out the fcrews by which it is ufually
fecured ;; it is then to be brought near the fire fo that
the filk may be perfectly dried, after which a little tal¬
low or fuet fliould be rubbed upon the cufliion, and it
fliould then be replaced in its fituation. If the filk of
the rubber is fitted to the cufliion by means of a wire
as defcribed in (42.) it will only be neceffary to take
out this wire, in order to dry the filk.
While both conductors remain infulated, the machine
will not continue to aCt long, or at leaff its aCtion will
be much lefs powerful) but if the negative conduCtor
or rubber be made to communicate with the floor or a
moiff wall, it will in general continue its aCtion for any
length of time required.
The weather is found to have confiderable influence
on the aCtion of an eleCtrical machine ) in wet weather
it will neither aCt fo powerfully, nor for fo long a time
as when the weather is moderately warm and dry, un-
lefs perpetual care be taken to keep every part of it
wrarm and clean. Very hot dry weather is alfo unfa¬
vourable to the aCtion of the machine, and*when this
happens, even the floor of the room may be too dry to
ferve as a conduCtor ) it is then necetfary to conneCt
the rubber by a chain which communicates with fome
moiff furface, as a cellar, a pump, or the like.
Mr Nicholfon lays down the following directions for Mr Nickoi-
preparing the machine for experiment. ton’s direc-
Clean the cylinder, and wipe the filk. for in-
Greafe the cylinder, by turning it againff a greafed
leather till it is uniformly obfcured. I ufe the tallow fv^vHn
of a candle. der.
Turn the cylinder till the filk flap has wflped off fo
much of the greafe as to render it femitranfparent.
Put fome amalgam on a piece of leather, and fpread
it well fo that it may be uniformly bright. Apply
tiffs againff the turning cylinder. The friction will im¬
mediately increafe, and the leather muff not be remov¬
ed until it ceafes to become greater.
Remove the leather, and the aCHon of the machine
will be very ftrong. * *
'Tranf. for
Chap. IV. An Enumeration of fome other Parts of Llii9-
an EleBrical Apparatus to be defcribed hereafter.
There are many other parts of the eledrical appara¬
tus) but thefe we can only enumerate here, as their de-
fcription and ufe will come more properly to be ex¬
plained
57
Chap. I. elec t 11
Principles of plained under tlie principles on which they are con-
Ekarkity ilrU(51ed.
13. reprefent different forms of coated
phials employed for the accumulation
power, and the ufual forms of the dif-
of the moft approved forms of
Fig. 12. and
jars or Leyden
of the eleftric
charging rod.
Fig. 14. fhews one
the electrical battery.
Fig. 15. reprefents a Hand fupporting four ele£tro-
meters for afcertaining the prefence and meafuring the
degree of electricity.
Fig. 17. exhibits the ufual form of the quadrant e-
lectrometer invented by Mr Henly, placed on the end
of the prime conductor.
Fig. 18. reprefents Mr Bennet’s gold-leaf eledtro-
Ineter.
Fig. 19
; Fig. 29
and fig. 30
Fig. 31. ,
difcharging rod.
Fig. 42. reprefents Mr Nicholfon’s inftrument
diltinguiihing pofitive and negative eleftricity.
Fig. 67. gives a view of Lane’s eleftrometer.
Fig. 68. and 69. reprefent Mr Brooke’s electrometer
as made by Mr Adams.
Fig. 70. reprefents Cuthbertfon’s compound or uni-
Verfal electrometer.
(hews Mr Cavallo’s pocket eleCtrometer.
reprefents Mr Henly’s univerfal difcharger j
a prefs belonging to it.
and 3 2. ftiew an outline of Mr Morgan’s
for
I C I T Y. 66 i
Fig. 71. and 72. are twro views of Dr Robifon’s com-PlinciPles°f
parable eleCtrometer. ' UluftratecT
Fig. 73. illuffrates the mode of ufing the eleCtro-eXperi_<
phorus. ment.
Fig. 80. is a figure of an eleCtrical machine in which
filk is employed as an eleCtric inftead of glafs.
Fig. 85. reprefents Bennet’s doubler, and fig. 86.
Nicholfon’s revolving doubler.
The reft of the apparatus figured in the plates will
be enumerated and fully delcribed in the fucceeding
parts of the article.
Befides the apparatus which we have defcribed and
enumerated, the eleCtrician Ihould have feveral glafs
tubes, fome of fmooth and others of rough glafs, flicks
of fealing wax, a piece of yellow amber, &c. for ex¬
citing pofitive and negative eleCtricity, wThen thefe two
ftates are to be obferved or compared.
It is of fome confequence that an eleCtrician fhould
have fome mechanical tafte; as he may often be re¬
quired to renew or repair parts of his apparatus, either
to' fave expence, or when he is at a diitance from a
fkilful workman. For this purpofe, few tools are ne-
ceffary. The principal are a turner’s lathe, for turn¬
ing caps, balls, pedeftals, &c. *, a blow-pipe wdth a
proper lamp, for bending tubes, or opening and clofing
fuch as are of large diameter j a few files of various
degrees of finenefs, and various forms, as flat, half-
round, rat-tail, See.
PART III.
AN EXPERIMENTAL ILLUSTRATION OF THE PRINCIPLES OF
ELECTRICITY.
rp WE propofe, in this part, to deferibe the principal
phenomena of communicated eleflricitij; and to illuf-
trate thefe by experiments, which we {hall, as nearly
as can be done, clafs under certain general heads or
principles. After recounting the experiments which
illuftrate each head, we fliall deferibe the conftruCtion
and explain the ufes of the feveral eleCtrical inftrum’ents
wLich depend on the principle laid down. We fhall
alfo take an opportunity, in this part, of tracing the
origin and progrefs of the more important difeoveries
which have been made in the experimental part of the
fcience.
As it muft be fuppofed that the reader is at prefent
unacquainted with the theory of eleCtricity, the princi¬
ples to which the feveral experiments in this part are
referred, will be merely fuch faCts or general pheno¬
mena as have been obferved in the courfe of experi¬
ment, independently of theory. In the following part
of this article, wre fliall endeavour more accurately to
illuftrate thefe phenomena, and explain them according
to the moft generally received theory of eleCtricity.
Chap. I. Of Electrical Attraction and Repulfton,
and the Jnjlruments which depend on them.
■fo An eleBrified body atiraCls bodies brought near it,
and after holding them in contact with it for fome time,
nyam repels them.
VOL; VIL Part II.
Experiment I.-—Sufpend a downy feather by a filkeit
thread •, on making it approach within a few inches of
the prime conductor, while the cylinder is fet in mo¬
tion, it will be attracted to the conductor, and almoft:
immediately repelled; and thus alternately attracted
and repelled, as long as the machine continues to be
worked.
This experiment may be thus varied in a pleafing
manner. Take a glafs tube, no matter whether fmooth
or rough, and, after rubbing it, prefent to it a dowmy
feather $ this will, as in the former inftance, be inftant-
ly attracted, and be retained for a ihorl time in contaCt
whh the tube ; when it will be repelled. If, at the
time of its repulfion, the tube be held in the air at a dif-
tance from furrounding objeCts, the repelled feather will
float above the tube, and may be driven about the room
as long as it does not touch any objeCt m its neighbour¬
hood. If one perfon hold a fmooth glafs tube, and an¬
other a rough tube or a flick of fealing wax, and a fea¬
ther be let loofe between them when excited, the fea¬
ther will leap from one to the other, and thus the two
perfons will feem to drive it between them like a fhut-
tlecock, whence this experiment is called the eleCirical ■
fhuttlecoch. 6 r
Exper. 2.—Let there be twx> metallic plates, one asDancing
c, fig. 20.Supported by a ftand, fo as that it may be^S11 l's'
placed on a table, &c. the other d provided with a P,ate
hook, by which it may be hung byachainto the prime0LXXXVirt’
4 P conductor^
666 ELECT
Principles ofcondu&or* at fome diftance from the other plate. Then
aiuftmed CUt ^°mC ^gures men or other obje&s in paper,
expeii- or> w^at better, form them out of the dry pith of el-
raent. der, or of rullies, and lay them on the lower plate. On
 i working the machine the figures will rife from the lower
plate, and move perpetually from the one plate to the o-
ther as reprefented in the figure.
Exper. 3.—Let a folid rod of glafs, as a, fig. 21. be
made to pafs through a bell b, perforated for the pur-
pofe, and let one end of the rod be fixed in a wooden
foot, while the other fupports two metallic arms, c d, efy
croffmg each other, and knobbed at their extremities.
From each extremity let a fmall bell without a clapper
be fufpended by a metallic wire, and from each arm, at
a little diilance from the extremities, let the clappers of
thefe bells be fufpended by filken threads. On con-
ne&ing the top of the Hand with the prime conductor,
and fetting the machine in motion, the clappers will be¬
gin to move between the central bell and the other four
lb as to ring the whole five.
Here the bells receive the eleftric power from the
prime condu&or, and being eleblrified, attraft and re¬
pel the clappers which hang freely between them.
Exper. 4.—Tie a fmall body, as for infiance a light
piece of cork, to a filk thread about eight inches long,
and holding the thread by its end, let the fmall body
hang at the difiance of about eight inches from the fide
of the prime condublor electrified. This fmall body, if
the electrization of the conductor is not ftrong, will not
be attracted. But if a finger or any conducting fub-
fiance be prefented to that fide of the fmall body which
is fartheft from the prime conductor, then the fmall
body will immediately move toward the prime conduc¬
tor j and when this body has touched the prime con¬
ductor, it will be inftantly repelled from it, on account
of the repulfion exifiing between bodies pofieffed of the
fame kind of electricity.
Indeed, if this infulated body be very , near to the
prime conductor, or the prime conductor firongly elec¬
trified, then the fmall body will be attracted without
prefenting to it any conducing fubftance $ or the natu¬
ral fluid belonging to that body will be all crowd¬
ed on that fide of it wThich is neareft to the prime
conductor.
If this fmall body, inftead of the filk, be fufpended
by a linen thread, it will be attracted at a much great¬
er difiance, than in the other cafe.
Bodies in the fame Jlate of eleflricily, i. e. which
are all eleElrfiedpof lively, or all negatively, have a ten-
dency to repel each other.
Exper. x.— Stick a downy feather into one of the
holes of the prime conductor. When the cylinder is
moved the feather will begin to fwell, and its plumes
will feparate to a confiderable difiance from each
other.
This experiment may be varied, by placing the re~
prefentation of a human head upon the prime conduc¬
tor. When the cylinder is moved, the hair of the
pjate head will brittle up and Hand ereCt as reprefented in
cuixxviii. fig. 22.
Exper. 2.—Let fmall balls made of cork or the pith
of elder well dried, be fufpended from the prime con¬
ductor by threads of an equal length. While the cylin¬
der continues at reft, the balls will touch each other,
but as foon as the machine is fet in motion they will
R I C I T Y. Part III.
repel each other to a greater or lefs difiance, accord-Principles of
ing as the eleCtric power produced is ftronger or Electricity
weaker. illuftrated
It is not neceffary that the threads be in ContaCt with
the prime conductor, for if the balls be brought near 1
the conductor while the machine is in motion, they will
recede from each other as before.
Ihe fame effeCt will be produced whether the
balls are hung from the pofitive or the negative con¬
ductor.
From the circumftance obferved in the above ex¬
periments we deduce the following important corol-
lary* • 63
ObjeBs brought near an eleclrifed body are eleftrifiedCqiqIXztj,.
by pofition.
The communication of eleCtricity from an eieCtrified
body, to another which is not in contaCt with it, but
is only in its vicinity, may for the prefent be conceived
by remarking that thefe bodies are furrounded with air.
Air, although an eleCtric, is not a very perfeCt eleCtric,
but is more or lefs alfo a conductor, efpecially when it is
moift. When a body is elettrified it communicates to
the air in contaCt with it a portion of its eleCtric power,
and thus the air becomes eieCtrified, and of courfe im¬
parts to the bodies, which are furrounded by it a degree
of eleCtricity 5 and this the more eafily as it is in a bet¬
ter conducting fiate.
The apparent aCtion of the air in communicating
eleCtricity to a body which is furrounded by it, may be
illuftrated by the following experiments.
Infulate in a horizontal pofition a metallic rod about
trvo feet long, having blunt ends, and at one of its ends
fufpend an eleCtrometer, like that reprefented in fig. 116}
then bring within three or four inches diftance of its
other end an excited glafs tube. On the approach of
the tube, the balls of the eleClrometer will open, and if
you prefent towards them a body politively eleClrified,
you will perceive that they diverge with pofitive elec¬
tricity. If the tube be removed, the balls come together
again, and no eleClricity remains in them, or in the me¬
tallic rod. But if while the tube is near one end of the
rod, and the balls diverge with pofitive eleClricity, the
other end of the rod, viz. that from which the eleCtro¬
meter hangs, be touched with fome conductor, the cork
balls will come immediately together, and they will re-
main fo when the conductor has been removed $—re¬
move now the excited glafs tube, and the balls will im¬
mediately diverge with negative eleCtricity j wdiich
ftiows that the rod remains eieCtrified negatively.
If the above experiment be made with an eleCtric ne¬
gatively eieCtrified (for inftance, a rod of fealing-wTax
inftead of the excited glafs tube) then the apparent elec¬
tricities in the rod will be juft the reverfe of wdrat they
were before ; for in this cafe, that end of the rod to
which the eleCtric has been prefented, will be pofitive,
and the oppofite end negative ; which oppofite end, if
touched in this ftate with fome conducting fubftance,
will acquire fome eleCtric power from that fubftance j
and when, after that fubftance has been removed, the ex¬
cited eleCtric is alfo removed, the rod will remain pofitive.
In making this experiment, care mutt be taken that
the end of the rod be very blunt, and that the eleCtric
be not very powerfully excited 5 otherwife a fpark may
pafs from this to the rod, which renders the experiment
precarious,
Take
Chap. I.
ELECTRICITY.
66y
Principles of Take two rods of metal, each about a foot long, fur-
Eledlricity ni{he(l ^vith knobs at both ends ; and, either by filk
b^ex^rf ^nes or b7 infulating ftools, infulate them, fo that they
Ycnt.H may ftand horizontally in one di reft ion, and about a
w—y—»< quarter of an inch diilance from one another. To the
middle of each of thefe rods hang an eleftrometer, like
that reprefented in fig. 16. This done, take an excited
glafs tube, and bring it to about three inches diitance
from the knob of one of the rods •, on doing which, the
eleftrometers of both rods will appear eleftrified : keep
the tube in that iituation for about two feconds, then
remove it. The rods now will remain eleftriiied, as
appears by the eleftrometers j the firit, viz. that to which
the excited tube had been preiented, remaining negative,
and the other pofitive.
In this experiment^ if, inftead of the glafs tube, an
eleftric, negatively excited, be brought near the end of
one rod, then that rod will be eleftrified pofitively, and
the other negatively.
This is all that we can properly explain at prefent
with refpeft to the agency of the air in the produftion
of eledtrical phenomena. We {hall take occafion to
confider this fubjeft more fully in a future part of this
article, when we {hall fee that a variety in the ftate
of the air produces confiderable diverfity in the pheno¬
mena.
On the principle of eleftric repulfion and the above
corollary depend the aftion of feveral inftfuments which
are of great ufe in eleftrical experiments, and which we
{hall now defcribe.
Inltruments which are employed to afcertain the pre¬
fence of eleftricity are called eleBrofcopes. As they
are generally employed to meafure the degree of elec¬
tricity produced, they are alfo called ele&rometers,
and by this name we {hall in future diftinguilh them.
The firft eleftrometer appears to have been conftruft-
ed by the abbe Nollet 5 it confifted of two threads of
filk, which, as has been Ihown, recede from each other
on the approach of an eleftrified body. He obferved
the angle of their divergency by its fhadow call on
a board placed behind them. Mr Waltz improved
this eleftrometer by appending fmall weights to the
threads *.
Mr Canton contrived an eleftrometer which is the
foundation of thofe which are now in common ufe. He
got a pair of balls turned in a lathe out of the dry pith
of elder 5 thefe he hung by threads of the fineft linen,
and kept them in a narrow box rvith a Hiding cover,
where they were fo difpofed that the threads could lie
ftraight. When he was to ufe it, he held the box by
the extremity of the cover, and allowed the balls to hang
freely from a pin to which they wrere fixed f.
Fig. 15. reprefents a {land fupporting the eleftrome¬
ters F)D, CC. B is the bafis of it, made of common
w’ood. A is a pillar of wax, glafs, or baked wood.
To the top of the pillar, if it be of wax or glafs, a cir¬
cular piece of wood is fixed j but if the pillar be of ba¬
ked wood, that may conftitute the whole. From this
circular piece of wood proceed four arms of glafs, or
baked wood, fufpending at their ends four eleftrome-
*4
Eledfro-
fcopes or
cledt rome-
ler.
65
Abbe Nol-
Jet’s.
* Hipoire
ie I'EledrU
■site.
66
Mr Can¬
ton’s elec¬
trometer.
f Phil.
“Tranf.
vol. xKx.
p. 300.
Plate
clxxxvh
ters, two of which, DD, are filk threads about eight Principles of*
inches long-, fufpending each a fmall downy feather at -{‘ftdcity
its end. The other two eleftrometers, CC, are thofe
with very {mall balls of ork, or of the pith of elder j
and they are conftrufted in the following manner :—a b
is a {tick of glafs about fix inches long, covered wuth
fealing-wax, and fhaped at top in a ring : from the
lower extremity of this {lick of glafs proceed twm fine
linen threads (m) cc, about five inches long, each
fufpending a cork or pith-ball */, about one-eighth of
an inch in diameter. When this eleftrometer is not
eleftrified, the threads cC hang parallel to each other,
and the cork-balls are in contaft $ but when eleftrified,
they repel one another, as reprefented in the figure.
The glafs Hick ab ferves for au infulating handle, by
which the eleftrometer may be fupported, when it is ufed
without the Hand AB.
Another fpecies of the above eleftrometer is repre¬
fented in fig. 16 ; which confifts of a linen thread, hav¬
ing at each end a fmall cork-ball. The eleftrometer is * Cavallo's
fufpended by the middle of the thread on any conduc-
tor proper for the purpofe, and ferves to {hew the kind ^ r'g'g
and quantity of its eleftricity *. 5-
Fig. 17. reprefents the quadrant eleftrometer of Mr Mr Hen-
Henly, one of the moll ufeful infiruments of the kind ley’s ciua"
yet difcovered, as well for meafuring the degree of elec-(bante*ec'’
tncity of anybody, as to afcertain the quantity of a
charge before an explofion j and to difcover the exaft
time the eleftricity of a jar changes, w7hen without
making an explofion, it is difcharged by giving it a
quantity of the contrary eleftricity. The pillar LM is
generally made of wrood, the graduated arch NOP of
ivory, the rod RS is made of very light wood, with a
pith ball at the extremity j it turns upon the centre of
the femicircle, fo as always to keep near its furface 5 the
extremity of the Hem LM may either be fitted to the
conduftor or the knob of a jar. When the apparatus
is eleftrified, the rod is repelled by the item, and moves
along the graduated arch of the femicircle, fo as to
mark the degree to which the conduftor is eleftrified,
or the height to which the charge of the jar is ad¬
vanced.
Beccaria recommends fixing the index between two
femicircles, becaufe when it is placed over one only,
the eleftricity of this repels and counteraft'i the motion
of the index. Other improvements and variations have
been made in this inftrument, which will be defcribed
hereafter.
The firit account of Mr Henly’s eleftrometer was
given in the Phil. Tranf. vol. Ixii. by Dr Prieftley, who
fpeaks of it in very high terms in a letter to Dr Frank¬
lin. He confiders it as a perfect inftrument for meafur-
ing degrees of eleftricity, but it will appear hereafter
that this is not the cafe.
The fcale in Mr Henly’s quadrant is divided into e-M. Ac-
qual parts ; but M. Achard has already {hewn that hard’s ob-
w'hen this is the cafe, the angle at wriiich the index isK'rvat'ons
held fufpended by the eleftric repulfion is not a true of tH "
meafure of the repulnve force ; to eftimate which truly, fcale.
he demonftrates that the arc of the eleftrometer Ihould
4 P 2 be
(m) Thefe threads fiiould be wetted in a weak folution of fait.
668
ELECTRICITY.
69
Mr Ben-
net’s elec¬
trometer.
Principles of be divided according to a fcale of arcs, the tangents of
illcctncity wbich are in arithmetical progreffion.
The balls of the ordinary electrometer may be made
of or of cork, but the latter mult be very fmooth and
well polilhed. They are belt made in a turner’s lathe.
They may be made of any lhape, provided they are
regular and free from edges. A very convenient elec¬
trometer is made of two long, {lender pieces of rufh
pith, made and appended to Ihort threads of flax.
Thefe may eafily be hung parallel to each other, where¬
as in the ufual ball-electrometers the threads to which
the balls are hung form an angle with each other.
This parallelifm of the threads is of advantage, and
was confidered of fo much confequence by Lord Stan¬
hope (better known to eleftricians by the title of
Lord Mahon) that he was at great pains to fufpend his
balls in a parallel polition.
Of all the inftruments by which it has been attempt¬
ed to meafure electricity, none have been found to an-
fwer the purpofe better than that invented by Mr Ben-
net, and which is reprefented in fig. 18. It confiits of
two flips of gold leaf, a a, fufpended in a glafs cylinder
b. The foot, c, may be made of wood or metal, and
the cap, d, Ihould be of metal •, the latter being made
flat at top for the convenience of putting any thing up¬
on it that is to be eledlrified. The cap is about an inch
wider than the diameter of the glafs, and its rim about
three quarters of an inch broad, hanging parallel to the
glafs to keep it fufficiently infulated, and to turn off
the rain, when the inftrument is employed in experi¬
ments on atmofpherical electricity. Within this is a-
nother circular rim about half as broad as the former,
lined with filk or velvet, fo that it may be made to
fit the outfide of the glafs exactly, while the cap may
be eafily taken off to repair any damage done to the
gold leaf. From the centre of the cap hangs a tin
tube fomewhat longer than the depth of the inner rim,
in which a fmall peg,_/i is placed, which may be taken
out occafionally. To this peg, which is rounded at one
end and flat at the other, two flips of gold leaf are falt-
ened with palte, gum water, or varnilh. They are a-
bout a fifth part of an inch broad and two inches long,
and are generally made tapering to a point. In one
fide of the cap is a fmall tube, g, to place wires in •,
h, k, are twro long pieces of tin-foil faftened with var-
nilh on oppofite fides of the internal fur face of the glafs,
where the flips of gold leaf may be expefted to ftrike,
and in connexion with the foot of the inftrument. The
upper end of the glafs is covered and lined with fealing-
wax as low as the outer rim, in order to make the in-
fulation more complete.
An improvement on this eletftrometer is to make the
?ntnt °f ^'scylinder pretty long, and to have a fmall additional tube
jultrument. ^ gum jac on en^ Gf 'Jpbe fl;pS 0f tinfoil reach
almoft to the edge of the outer rim, and are lharp point¬
ed at the top, wridening in the middle and decreafing in
breadth again as they defcend.
Advantages The great advantage of this inftrument over the elec-
of this in- trometers which we have defcribed above is its extreme
itrument. fenfibility, which will appear from the following ex-
amples.
Its extreme I. On putting powTdered chalk into a pair of bellows
fenfibility. and blowing it upon the cap, this was electrified pofi-
tively when the nozzle of the bellows was about fix
inches from it; but at the diftance of three feet from the
7°
Irnpr.
Part IIL
nozzle, the fame ftream eleCtrificd the cap negatively. Principiesof
Thus it appears that the electricity may be changed from Electricity
poiitive to negative merely from the circumftance of this (‘^dtratecl
ftream of chalk being more widely diffufed ih the air. ™
It may alfo be changed by placing a bunch of fine wrire,' v— ■>l
filk, or feathers, in the nozzle of the bellows: and it is
likewife negative when the air is blown from a pair of
bellows wanting the iron pipe, fo that it may come out
in a larger ftream ^ but this laft experiment fucceeded
belt when the air was damp. There is likewife a re.
markable difference between the experiments in which
the eleftricity is pofitive and that in which it is nega¬
tive j the former being communicated to the cap with
fome degree of permanency, fo that the flips of gold leaf
continue for fome time to diverge 5 but the latter being
only momentary, and the flips collapfing as foon as the
cloud of chalk is difperfed. The greater permanency
of the eleCtricity in the former cafe is owing to fome of
the chalk fticking to the cap when the nozzle of the
bellows is very near it.
2. A piece of chalk drawn over a brufh, or pow¬
dered chalk put into the brufh, and projected upon
the cap, eleCtrifies it negatively 5 but its eleCtricity is not
communicated.
3. Powrdered chalk blown with the mouth or bellows-
from a metal plate placed upon the cap, communicates
to the cap a permanent pofitive eleCtricity. If the chalk
is blown from the plate either infulated or not fo, that
the powder may pafs over the cap, if not too far off, the
eleCtricity communicated is alfo pofitive } or if a brrih
be placed upon the cap and a piece of chalk be drawn
over it, the flips of gold-leaf when the hand is withdrawn
gradually open with pofitive eleCtricity as the cloud of.
chalk difperfes.
4. Powdered chalk falling from one plate to ano¬
ther placed upon the inftrument eleCtrifies it nega¬
tively.
Other methods of producing eleCtricity with chalk
and other powders have been tried 5 as projecting chalk
from a goofe 'wing, chalking the edges of books and
clapping the leaves of the book fuddenly together, alfo
lifting the powrder upon the cap, all which eleCtrified it
negatively 5 but the inftrument being placed in a dully
road, and the dull ftruck up with a Itick near it, elec¬
trified it pofitively. Breaking theglafs-tear upon a book
eleCtrified it negatively, but when broken in wrater it did
not eleCtrify it.
Wheat flour and red lead produced a ftrong negative
eleCtricity in all cafes where the chalk produced a pofi¬
tive eleCtricity. The following powders were like chalk:
red ochre, yellow rofin, coal allies, powdered crocus
metallorum, aurum mofaicum, black-lead, lamp-black
(which was only fenfible in the two firft methods), pow¬
dered quick-lime, umber, lapis calaminaris, Spanilh
browm, powdered fulphur, flowers of fulphur, iron filings,
ruft of iron, fand. Rofin and chalk, feparately alike,
were changed by mixture ; this was often tried in dry
weather, but did not fucceed in damp ; white-lead alfo
fometimes produced pofitive and fometimes negative elec¬
tricity when blown from a plate.
If a metal cup be placed upon the cap with a red hot
coal in it, and a fpoonful of water be thrown in, it
eleCtrihes it negatively •, and if a bent wire be placed
in the cap, with a piece of paper faftened to it to in-
creafe its furface, the poiitive eleCtricity of the afeend-
ing
by experi¬
ment.
Chap. I. L E C 1
Principles of ing vapour may be tried by introducing the paper in-
Electricity t0
ilhiftrated The fenfibility of this eleftrometer may be confider-
ably increafed by placing a candle on the cap. By
v  this means, a cloud of chalk, which in the other cale
73 only juft opens the gold-leaf, will caufe it to ftrike the
Itsfeniibili-ficles £or a iong time together', and the electricity which
lwas not before communicated, now pafles into the elec-
el candle, trometer, cauling the gold-leaf to repel after it is car¬
ried away. Even fealing-wax by this means communi¬
cates its eledlricity at the diftance of 12 inches at
leaft, which it would fcarcely otherwife do by rubbing
upon the cap.
A cloud of chalk or wheat flour may be made in one
room, and the electrometer with its candle be afterwards
R I C I T Y. 669
which attends the electrometers in which cork or pithPrmci[jlesuf
balls are employed. In thefe, when the balls are e1iec" j:pufl.rateci
trifled, they are very apt to adhere together for lome ^ experi-
time before the repulflon takes place, and then they ment.
often feparate with a jerk fo as to recede from each v " f
other farther than 'they [ought to do, and thus make
the eleftricity produced appear greater than it really
is 5 whereas the flips of gold-leaf in Bennet’s electrome¬
ter do not adhere together, and feparate equally and
gradually. 74
This inftrument is, however, not without its defects,Its detects,
as the delicate texture of the gold-leaf renders it very
difficult to fallen the flips, fo as to keep them entire,
and alfo prevent the inftrument from being eafily re- 75
moved from one place to another. Mr Cavallo pro-Cavalio^s
leifurely brought from another room, and the cloud
wall electrify it before it comes very near. The air of
a room adjoining to that wherein the electrical ma¬
chine wras ufed, was very fenfibiy electrified, which was
perceived by carrying the initrument through it with its
candle.
No fenfible eleftricity is produced by blowing pure
air, by projecting wTater, by fmoke, flame, or explofions.
of gun-pow'der.
A book wras placed upon the cap, and {truck with
fllk, linen, woollen, cotton, parchment, and paper, all
which produced negative repullion •, but when the other
fide of the book was ftruck with fllk, it became pofltive;
this fide, ftruck at right angles with the former, was a-
gain negative 5 and by continuing the ftrokes which,
produced pofitive, it changed to negative for a little
while •, and by flopping ag.dn, became pofltive. No
other book would do the lame, though the fides were
fcraped and chalked, upon a fuppofition that altering
the furface wTould produce it. At laft, one fide of a
book was moiftened, which changed it; whence it was
concluded, that one edge of the book had lain in a
damp place •, which conjeCture was farther confirmed
by all the books becoming pofltive in damp weather,
and one of them being dried at the fire again became
negative.
When the cap is approached with excited fealing-
wax, the gold-leaf may be made to ftrike the fides of
the glafs more than twelve times ; and as the fealing-
wTax recedes, it ftrikes nearly as often j but if it ap¬
proaches much quicker than it recedes, the lecond num¬
ber will fometimes be greater.
The quantity of eleftricity neceffary to caufe a re-
pulfion of the gold-leaf is fo fmall, that the lharpeft
points or edges do not draw it off without touching }
hence it is unneceffary to avoid points or edges in the
conftruftion of this inftrument.
To the experiments on blowing powders from a pair
of bellows, it may be added, that if the powTder is blown-
at about the diftance of three inches upon a plate which
is moiftened or oiled, its electricity is contrary to that
produced by blowing upon a dry plate. This Ihews
that the eleClricity of the llreams of powder iffuing out
of the bellows is only contrary to the more expanded
part, hecaufe it is wdthin the influence of its own at¬
mosphere •, for when this is deftroyed by the adhefion
of the pow der to the moiftened place, it is negative
when the bellows are pofitive, as it wTas betore pofitive
when the more expanded cloud was negative.
This inftrument is alfo free from an inconvenience
3
pofes to remedy thefe defects in the following manner re“
When the flips are cut and are lying upon paper, or^^J^
on the leather culhion upon which they are cut, makefeiqs.
them equal in length, by meafuring them with a pair
of compaffes, and cutting off a fuitable portion from
the longeft j then cut two bits of very fine gilt paper,
each about half an inch long, and a quarter of an inch
broad, and by means of a little wax, flick one of them
to one extremity of each flip of gold-leaf, fo as to form a
kind of letter T. This done, hold up in the fingers of
one hand, one of thofe pieces of paper with gold-leaf
fufpended to it, and hold the other with the fingers of
the other hand j then bringing them near to each other,
and having adjufted them properly, viz. fo as to let them
hang parallel and fmooth, force the pieces of paper which
now touch each other, between the two fides of a lort
of pincers made of brafs ware, or of very thin and
hammered brafs plate, which pincers are faftened to the
under part of that piece which forms the top or cover
of the glafs veffel. As thefe gold flips are very apt to
be fpoiled, we fhould keep feveral of them ready cut
in a book, each having a crofs piece of paper faftened
to one extremity, fo that in cafe of accident, a new
pair of gold flips may be foon put between the aperture
of the above-delcribed pincers} and by this means
the electrometer is rendered, in a certain manner, por¬
table. 7 <5
Mr Cavallo defcribes an electrometer which is nearly Mr Caval-
as fenfible as Mr Bennet’s, and is not liable to the in-^^P®^^
conveniences above mentioned. It is reprefented atter>
%• I9-
The cafe or handle of this eleftrometer is formed
by a glafs tube, about three inches long, and three-
tenths of an inch in diameter, half of which is covered
with fealing-w-ax. From one extremity of this tube,
i. e. that without fealing wax, a fmall loop of filk pro¬
ceeds, which ferves occafionally to hang the electrome¬
ter on a pin, Stc. To the other extremity of this tube
a cork is adapted, which, being cut tapering on both
ends, can fit the mouth of the tube with either end.
From one extremity of this cork, two linen threads
proceed, a little fliorter than the length of the tube,
fufpending each a little cone of pith of elder. When
this electrometer is to be ufed, that end of the cork
which is oppofite to the threads is pulhed into the
mouth of the tube 5 then the tube forms the infulated
handle of the pith electrometer, as reprefented fig. 19.
c. But when the electrometer is to be carried in the
pocket, then the' threads are put into the tube, and the
cork flops it, as reprefented at b. The peculiar advan¬
tages
„ .77
Capi.lary
fvphon.
670 ELECT
Principlesoftiiges of tins eleclroiECter ^re, its convenient fmall fize,
Pluftrateif *tS Sreat fenubllity, and its continuing longer in good
by experi- order than any other we have yet feen.
ment. a, Reprefents a cafe to carry the above-defcribed elec-
v tromer in. This cafe is like a common tooth-pick cafe,
except that it has a piece of amber fixed on one extre¬
mity A, which may occafionally ferve to electrify the
eleidrometer negatively, and on the other4extremity it
has a piece of ivory fattened upon a piece of amber
BC. This amber EC ferves only to infulate the ivory,
which, when infulated, and rubbed again ft woollen
cloths, acquires a pofitive ele&ricity *, and it is therefore
ufeful to electrify the electrometer pofitively.
There are many other electrometers employed by
electricians ; but thefe cannot properly be deferibed at
prefent, as they are conftruCted on principles which
have not yet been explained. They will be noticed in
their proper place.
The cleftric power forces a fluid to flow in a flream
through a capillary tube, through which, when not elec¬
trified, it would only pafs in dropsi
Exper. I.—Sufpend a imall metallic bucket
full of water from the prime conductor, and place in
the water a glafs fyphon, the diameter of whofe tube is
fb fmall that the water will only drop from it. Now
fet the cylinder of a machine in motion, and the water
will begin to flow in a full ftream from the end of the
fyphon. The ftream will fometimes be fubdivided,
and if the experiment is made in the dark, the water
will appear luminous-
Exper. 2.—Dip a fponge ‘in water, and fuf-
pend it from the prime conductor. The water which
before only dropped from the fponge, will now flow
very fall, and appears in the dark like fiery ram.
The effeCt of eleCtricity on water flowing through
Capillary tubes, was firft obferved by M. Boze , but
was more accurately inveftigated by the Abbe Nollet.
He found that the ftream of water through a capillary
tube, was accelerated in the inverfe ratio of the diame¬
ter of the tube ; but that if the diameter of the tube,
was lefs than a line j the ftream was not fenfibly accel-
rated. The important application which the abbe thought
he could make of this experiment will be feen hereafter.
When an infulated vejfel is eietlrified, and an infulat¬
ed body, fuch as a ball-eleElrometer, is fufpended within
the cavity of the vejfel, the body Jhows noflgns of elec¬
trical attraction or repulficn.
The experiment by which this principle is to be il-
luftrated, is called the eleElrical well, and is thus de¬
feribed by Mr Cavallo.
“ Place upon an eledric ftool a metal quart mug, or
fome other conducting body nearly of the fame form
and dimenfion j then tie a fhort cork-ball eleClrometer,
of the kind reprefented fig. 3 6. (n), at the end of a filk
thread proceeding from the ceiling of the room, or
from any other proper fupport, fo that the eleClrometer
may be fufpended within the mug, and no part of it
may be above the mouth ; this done, eleCtrify the mug,
by giving it a, fpark with an excited eleCiric or other-
wife, and you will fee that the ele&rometer, whilft it
R I C I T Y.
Part III.
7»
79
JSleftrical
Well.
remains in that infulated fituation, even if it be made Principles»f
to touch the fides of the mug, is not attra&ed by it, Eledlricity
nor does it acquire any eleCtricity ; but if, whilft it ^lu^£ratfc.^
ftands fufpended within the mug, a conductor ftanding ^menz.^
out of the mug be made to communicate with, or only
prefented to it, then the eleCfrometer acquires an elec¬
tricity contrary to that of the mug, and a quantity of
it, which is proportionable to the body with which it
has been made to communicate j and it is then immedi¬
ately attracted by the mug.
If, by railing the filk thread a little, part of the
electrometer, i. e. of its linen threads, be lifted juft a-
bove the mouth of the mug, the balls will be immedi¬
ately attracted j for then, by the aCtion of the eleCtri¬
city of the mug, it will acquire a contrary eleCtricity,
by giving to, or receiving the eleCtric power from, the
air above the cavity of the mug.”
This experiment may be made in greater perfection
by employing a globular glafs veffel, with a narrow
neck juft fufticient to admit the eleClrometer, which
Ihould be faftened to a crooked glafs rodr fo that it
may be prefented to any part of the cavky. The out-
fide of the veffel Ihould be fmeared with fome clammy
fubftance, as fyrup or treacle, and may be infulated
J»y placing it on a wine glafs. The balls prefented to
the outfide when the veffel is eleCtrified, will be repel¬
led, but prefented to any part of the infide, they will
(how no figns of eleClricity, unlefs touched with fome
febftance, as a wire, while within the cavity j when, on
being taken out, they will repel each other.
This experiment was invented by Dr Franklin, and
is called by him the eleElrical cup.
CflAP. II. Of the diverflties exhibited by the eleBric
power in its paffage from pointed furfacesy and
from obtufefurfaces.
When the electric power paffes between an ele&rifled gc.
body and a pointed conduBor, a luminous flream is
produced, attended with a current of air from the
point.
Exper. 1.—Fix a metallic point in the prime
conduClor, and fet the machine m motion. No crack¬
ling, but rather a hilling noife, will be heard, and a
light will appear as if ifluing from the point, and on
holding the hand near it, a Itrong blait of air will be
found to proceed from it. On holding another point
at the diftance of about half an inch from the point in
the prime conduCtor, a ftream of light will be feen paf-
fing between them, attended with a crackling noife.
This current of air will be fuftkiently ftrong to turn
any light bodies which are freely fufpended, and in
this way the following pleafing experiments may be
made.
Exper. 2.—Cut a round flat piece of cork*
with the edges very fmooth, and flick a number of
fmall crow quills into the circumference, with the fea¬
ther ends as reprefented in fig. 23. } pafs a needle p]ate
through the centre of the cork, and fufpend this needle cLxxxvm.
by a fmall magnet nt; on holding the cork near the
point
(n) Inftead of the eleClrometer, there may be ufed any other kind of fmall conducting body j but that feerns
heft adapted to- fuch experiments.
8l
Electrical
borfe-race.
8z
Electrical
arrery.
Chap. II. EL E C I
Principles of poirit, tlie current of air will make it move round with
Electricity great fwiftnefs.
illuftrated Exper. 3.—Let four arms of wire, with their
^ment. extremities pointed and turned all in the fame direction,
be ftuck in the circumference of a fmall circular piece
of light wood, fupported on a pointed wire, as repre-
fented in fig. 24. On bringing the wires near the
point in the conductor, while the machine is in motion,
they will move fwiftly round as before, and in the
dark, a beautiful circle of fire will be produced by the
light ifiuing from the points. If figures of dogs, horfes,
&c. formed of elder pith, be ftuck on the points, they
will appear as if purfuing each other, thus forming what
Mr Kinnerfly called the electrical horfe-race.
Exper. 4.—Fix eight bells near the edge of a
circular board fupported on four feet, as reprefented
fig. 25, having a glafs pillar e in the centre, terminat¬
ed by a point g. On this point place the pointed wares
ufed in the laft experiment, hanging from one of them
as </, a fmall glafs clapper by a filken thread j and con¬
necting the apparatus by a chain h, proceeding from
the prime conductor. On fetting the machine in mo¬
tion,. the wire will move round, and the clapper rmg
the bells.
Exper. 5.—-By this motion of circulating points
we may in fome meafure imitate the revolutions of the
heavenly bodies, forming what is called the electrical
orrery. Let a- fingle wire, with the extremities point¬
ed and turned as before, be nicely balanced on a point j
fix a fmall glafs ball over its centre, as a, fig. 26, to re-
prefent the fun. At one extremity of the wire, let a
fmall wire be foldered perpendicularly, and on this ba¬
lance another fmall wire with its ends pointed and turn¬
ed, and having a fmall pith ball w in its centre to re-
prefent the earth, and a fmaller ball of the fame kind
at one of the angles for the moon. Let the whole be
fupported upon a glafs pillar, and be conducted by a
chain proceeding from the prime conductor to the wire
fupporting the glafs ball. Now, when the machine is
put in motion, the wires will turn round, fb that the
ball reprefenting the earth wall move round the central
• ball, and the little ball at the angle of the fmaller wire
g wrill at the fame time revolve about the earth.
Gravitation Exper. 6.—The power exerted by eleClricity
refitted by upon points, may under fome circumftances be made
the adtion to counteraCl the power of gravitation. Let an inclin-
of points. ecj pjane j-,e formed of two parallel wires faftened by
their extremities to four pillars of folid glafs, M, N, O, P,
fig. 27. fixed in a board fo that the two at one end fhall
be higher than the other twTo. Then fix a wire with
its ends pointed and turned in the fame direction, at
right angles upon a wire axis. When this axis is laid
upon the inclined plane, it wall of courfe roll to the
bottom, but if, when it has nearly arrived there, the
machine be put in motion, the wire will return up the
plane, revolving on its axis.
Exper. 7‘—Take a fmall lock of cotton, ex¬
tended in every direction as much as can conveniently
be done, and by a linen thread about five or fix inches
long, or by a thread drawm out of the fame cotton, tie
it to the end of the prime conductor 5 then fet the ma¬
chine in motion, and the lock of cotton on being elec¬
trified, will immediately fwell, by repelling its fila¬
ments from one another, and will ftretch itfelf towrards
the neareft conductor. In this fituation let the cylin-
& I G I T Y.
671
*4
The eke-
trified cot
ton.
der be kept in motion, and prelent the end of your firw Principles of
ger, or the knob of a wire, towards the lock of cotton,
which will then immediately move towards the finger, ^y experi-
and endeavour to touch it 5 but take with the other ment.
hand a pointed needle, and prefent its point towards 'v''*—
the cotton, a little above the end of the finger, and the
cotton will be obferved immediately to (brink upwards,
and move towards the prime conduClor. Remove the
needle, and the cotton will come again towards the
finger. Prefent the needle, and the cotton will (brink
again.
When the electric power pajfss between an elcBrified 85
body and a conduClor whofe furface is obtufe, a luminous
/park is produced, attended with an explojion, and thefe
appearances are more or lefs Jlrong in proportion as the
furfaces are more or lefs obtufe. 35
Exper. 1.—When the prime conduClor is fitu-Drawing-
ated in its proper place, and eleftrified by whirling the (parks,
cylinder, if a metallic wire with a ball at its extre¬
mity, or the knuckle of a finger, be prelented to the
prime conduClor, a fpark will be feen to ilfue between
them, which will be Kjore vivid, and wTill be attended
with a greater or lefs explofion, according as the ball,
is larger. The ftrongeft and mod vivid fparks are
drawn from that end or fide of the prime conduClor,
which is fartheft from the cylinder. The fparks have
the fame appearance whether they be taken from the
politive or the negative conduClor j they fometimes ap¬
pear like a long line of fire reaching from the prime
conduClor to the oppofed body, and often (particularly
when the fpark is long, and different conduCling fub-
ftances in the line of its direction) it will have the ap¬
pearance of being bent to (harp angles in different
places, exaClly refembling a tlafti of lightning. 87
The figure of the fpark varies with the fuperficial Figure of
dimenfions of the part from which it is taken. If it^e elednc
be drawn from a ball of two or three inches in diame- ^
ter, it will have the appearance of a ftraight line ; but
if the ball from which it is drawn be much fmaller, as
half an inch in diameter, it wail aflame the zig-zag ap¬
pearance above mentioned.
We have juft feen that when tire eleCtric power paf-
fes from a point to a point, there are no fparks, but a
luminous dream appears j but if the point be obliterat¬
ed, by being thruft back fo as to be on a level with the
furface of the conduClor, by being held between the
fingers &c. the fparks will appear as before. g8
The length of the fpark, or the didance through the Length of
air which it ftrikes from the conduClor, depends on fe~ me ipark.
veral civcumftances j as, the length and diameter of
the conduClor *, the termination of the furface from
which, or to which, the fpark paffes 5 the dimetilions
of the cylinder j and the pofition of the conduClor.
1. If the conduCling body be increafed in length
only, the diilance of the fpark will be (hortened. This
faCt was very early obferved by Dr Prieftley. He
found that a fpark from the end of a wire feveral yards
in length, and about one fourth of an inch in diameter,
wras not longer than one taken from a conduClor two
feet in length, and two inches in diameter. Signior
Volta found, that when he conneCled feveral rods, eight
feet long, and half an inch in diameter, fufpended at
the diftance of eight inches from each other, the fpark
drawn from them was not fo long as one drawn from
a conduClor of the fame length, but of twelve inches
diameter.
fiyJ E L E C T R
Principles of diameter. Mr Brook of Norwich connected nearly
electricity twenty rods of wood covered with tin-foil, near feven
illuttraied £eet ancl three-fourths of an inch in diameter, at
about a foot from each other, fo that the whole appa¬
ratus refembled a large gridiion, which was fufpended
from the cieling by glafs rods. From fo large an ex¬
tent of condudting furface no fpafk exceeding fix inches
could be drawn •, whereas from a conductor eight feet
long, and five inches in diameter, fpurks may often be
drawn above nine inches long, with the fame cylinders
2. If the diameter of the conductor be increafed in
proportion to its length* the fpark is not fo long as
when it is fhortened, while the diameter is increafed.
A conductor twelve feet long, and eight inches in dia¬
meter, does not yield a ipark above half the length
that may be drawn from a conductor of the fame dia¬
meter, only fix feet long.
3. The fpark will Itrike to a greater diftance, accord¬
ing as the cylinder is fmaller in proportion to the con¬
ductor. A much longer and more violent fpark was
drawn from Mr Brook’s gridiron conductor with a cy¬
linder only four inches in diameter than from a conduc¬
tor five feet long, and fix inches in diameter, with the
fame cylinder.
4. The length of the fpark is greater from a ball of
moderate dimenfions than from the furface of the prime
conductor.
5. The fpark wall be longer when the conductor is
placed parallel to the cylinder, than when it is at right
89 angles with the cylinder.
Sound of Xhe found of the fpark varies according as the fur-
the fpark. £aces ketween which it ftrikes are more or lefs obtufe. It
is louder wdien the fpark is taken from the prime con-
duCtor, than when taken from a ball. annexed to it ;
imd it is loudeft of all when the fpark ftrikes from one
flat furface to another : a ftraight fpark is always loud¬
er than one of the zig-zag appearance. If the fpark
be made to pafs from one end of a glafs tube (clofed
at both ends and very dry) to the other, the found is
90 entirely hufhed.
Force of When the fpark is received by the knuckle it pro-
the fpark. duces a fenfation which is, more or lefs painful. It is
more pungent when received from the prime conductor
than from a ball attached to it. The fpark produces
a more painful fenfation in proportion as it is flior-
91 ter.
light of the The moft remarkable circumftance attending the elec-
fpark. trjc fpark ;s the light £0) produced in its palfage through
the air. The fparks which ufually pafs between the
rubber of the negative conductor, through the cylinder
to the points of the pofitive.conduCtor, are of a beauti¬
ful light blue colour •, but when the fpark naffes be¬
tween the prime conduCtor and a ball of the diameter
of an inch, its edges are purplhh, and fromthefe diverge
feveral ramifications of a purple or indigo colour. If
the balls between which the fpark paffes are not more
than half an inch diltance from each other, a continued
itream of the molt brilliant light will be produced, at¬
tended with a whizzing noife. If the diltance of the
illuftrated
by experi¬
ment.
1 C I T Y. . Part HR
balls from each other be increafeu, fparks equally bril-Principles of
liant will be produced ; but their fucceflicn will be lefs Ele<bncity
r -in -n ., j
quick, and no continued Itream will appear.
The light emitted from electrified conductors is more
copious and brilliant in proportion as their furfaces are '
more extended. If a perfon Handing on an infulating
Itool, and connected with the prime conductor of a ma¬
chine in motion, hold a flat plate ol metal, as a pewT-
ter plate, while another perlon Handing on the
floor holds another plate, large flalhes of vivid light
will appear between the plates, fo as to illuminate a
dark room. v 92
Soon after the cylinder is fet in motion, and fparks Peculiar
begin to ilfue, a peculiar odour may be perceived 5 and°at~j
if the machine aCts well, this is very powerful. It isfp^, “
difficult to delcribe this odour, but it feems to refemble
that of phofphorus.
Chap. III. Of charging and difcharging the Leyden
Phial; with directions for the conjlruction of Jars
and Batteries.
The eleBric power is communicated to electrics with 93
difficulty, unlefs their furfaces be covered with fame
condutiing fubfiance ; but it may be accumulated on them
in a much greater degree than on conductors.
Exper. 1.—Take a common tumbler or glafs Dancirg
jar, and having placed a brais ball in one of the holes balls,
of the prime conductor, fet the machine in motion,
and let the balls touch the infide of the tumbler; while
the ball touches only one point, no more of the furface
of the glafs will be eleCtrified, but by nioving the tum¬
blers about fo as to make the ball touch many points
fucceflively, all thefe points will be eleCtrified, as will
appear by turning down the tumbler over a number of
pith or cork balls placed on a table. Thefe balls wall
immediately begin to fly about, thus fhowfing the elec¬
tric attraction and repulfion illufirated in (61). This
experiment is coinmonly called the experiment of the CLXxa^nr
dancing balls, and is reprefented at fig. 28. 95
Exper. 2.—Let a glafs jar, either cylindrical, fuch asConftmc-
is reprefented at fig. 12. Plate CLXXXV1I. or withtion of the
as wide a mouth as poflible, be covered on both its in-^, w|en
fide and outfide furfaces to wathin two inches of the top,
with tin foil faHened on by means of gum wTater. The
jar is then faid to be coated. Fit to the mouth of the
jar a piece of baked wood, through the centre of which
pafs a wire, whofe lower extremity is terminated by a
number of other wires, wdiich mufl be made to touch
the infide coating, while its upper extremity pro¬
jects an inch or two above the mouth of the jar, and
terminates in a metallic ball a. This ball fliould be
perforated fo as to receive a wire fupporting a quadrant
eleCtrometer. ^5
The jar being thus prepared, let the knob a com-Met odtf
municate with the prime conductor, and let it remain cliar5qng
while the cylinder is in motion till the ball c of ther
eleCtrometer Hands nearly horizontal ) the jar is then' ld Sing
faid to be charged- It may be removed from the con-
duCtor
(o) The firH perfon who feems to have obferved the eleCtric light was Otto Guericke. Fie appears indeed on¬
ly to have had a glimpfe of jt; and the firH who perceived it in any great degree was Dr Wall, on rubbing a
pretty large piece" of amber. Vid. Philof Tranfi abridged, vol. ii.
Chap. m.
ELECTRICITY.
671
illuitrated
by experi¬
ment.
Principles of du£lof without any cffe$: being produced fc long as the
Electricity tp,e infJ(]e coating has no communication with the out-
fide.
Let there be provided a curved brafs rod, termina¬
ting at each end in a knob, and furnilhed with a glafs j
handlej fuch as D e f; if now one of the knobs, as
be made to approach the ball a of the jar, while the
other knob f touches the outfide coating, a conlider-
able explofion will take place, and the jar will lofe
its eleftricityj as will appear by the ball oi the eledtro-
meter falling into a perpendicular fituatiom
The jar is then faid to be difcharged, and the tod def
is called a difcharging rod.
A jar or phial of glafs thus conftrufted is, for a reafon
which will prefently appear, called a Leyden jar or phial.
In this experiment, the jar is not charged to its ut-
tnoft height. If, initead of hopping when the index of
the quadrant is nearly at right angles, we perfift in
charging, there will foon appear feveral luminous
ftreams pafiing from the prime conduftor acrofs the
'cylinder to the cufhion. Prefently an explolion will
take place from the phial, and this is called its fpon-
ianeous difekarge. If the phial is not very ftrong,
it will probably either be broken, or on examination
will be found perforated in fome part. If the glafs
be very thin, a fpontaneous difeharge will foon take
place, attended with a harih crafhing noife, and
the phial will certainly be cracked. A fpontaneous
difeharge happens much more readily when the neck
of the phial is very fmall, and cohfequently the ware
comes very near the uncoated part of the glafs.
If the uncoated part of the glafs be moiil or dufty,
the jar will not receive a charge* fo that it is neceffary
to be very careful in cleaning the jar before ufmg it.
When the uncoated part is made very hot, the fpon¬
taneous difeharge is much accelerated.
The appearance of the uncoated part of the jar* when
the difeharge is made in the dark, is very curious. A
great number of luminous dreams will be feen pouring
over the edge of the jar from the inlide to the outfide.
The force of the explofion depends very much on
the termination of the extremity of the difcharging rod.
If this be terminated by a large ball, the noife will be
much greater than when the ball is fmall •, if it be ter¬
minated by a fmall obtufe furface, a hiding noife is
heard before the explofion, and this is faint. But if
the rod terminate in a point, no explofion will take
place, but the jar will be filently difeharged.
In the above experiment the jar is charged pofitively,
it having been in contadl with the pofitive conductor ;
but if it be connetled with the negative condudlor, the
jar will be charged negatively. This will be more
fuby illuftrated by and by.
As the accumulation of the electric power by means
of coated jars forms one of the mod important difeover-
ies which have been made in this fcience, we fhall here
relate the method in which the difeovery was made.
This difeovery was accidental, and was the refult of
lhc Ley-jm experiment made in the end of the year 1745 by
Van ^ran Kleid, dean of the cathedral in Cammin, who
kleift. 1 feut the following account of it to Dr Leiberkuhn at
Berlin.
When a nail or a piece of thick brafs-wire, &c. is
put into a' fmall apothecary’s phial, and eledlrified, re¬
markable e(redds follow; but the phial mud be very dry
Vol„ VII. Part IT
..97
I)ifcovery
ledtricfty
iiluftrated
by experi¬
ment.
or warm. I commonly rub it once before hand with a Principles of
finger, on which I put fome pounded chalk. If a little
mercury, or a few drops of fpirits of wine, be put into
it, the experiment fucceeds the better. As foon as
this phial and nail are removed from the eledfrifying 1—-y—
glals, or the prime condudtor to which it has been ex-
pofed, is taken away, is taken awray, it throws out a
pencil of dame fo long, that with this burning machine
in my hand, I have taken above fixty deps in walking
about my room. When it is eleddiied drongly, I can
take it into another room, and there fire fpirits of wine
with it. If, while it is eleftrifying, I put my finger,
or a piece of gold, which I hold in my hand, to the
nail, I receive a diock which duns my arms and
droulders.
A tin tube, or a man placed upon electrics, is elec-'.
trifi«4fcj!nuch dronger by this means than in the com¬
mon way. When I preient this phial and nail to a tin
tube, which I have, fifteen feet long, nothing but ex¬
perience can make a perfon believe how drongly it is
eleftrified. Two thin glaffes have been broken by the
Ihock of it. It appears to me extraordinary, that when
this phial and nail are in contact with either conducing
or non-condu£ting matter, the drong (hock does not
follow. I have cemented it to wood, metal, glafs,
fealing-wax, &c. when I have electrified without any
great effect.
M; Van Kleid communicated this experiment to fe¬
veral of his acquaintances, but they all for fome time
failed in their attempts to repeat it. ^
An experiment of a fimilar kind was foon after made Experi-
at Leyden by Mr CuneuSi Making an attempt to ment by
communicate the eleCtric pow’er to water, contained in Cunedfc
a phial, in which was a nail, happening to hold his
glafs in one hand, while he difengaged it from the
prime conductor with the other, when he imagined
that the water had received as much eleCIricity as it
was capable of acquiring, he was furprifed with a hid¬
den lhock in his arms and bread, which he had not in
the lead expeCted.
This experiment was afterwards repeated in the pre¬
fence of M. M. Allamand and Mufchenbroeck with
fimilar refults; and as it wras at Leyden that the expe¬
riment was made with the greateit fuccefs, and after¬
wards improved, it obtained the name of the Leyden
experiment, and a phial fo condructed as to exhibit fi¬
milar phenomena, has been ever fince called a Leyden
phial.
Indeed the philofophers of Leyden feem to have
fome merit in this difeovery, which with them does which led
not appear to have been merely accidental. The views to tins dif-
which are -aid to have led to it were as follow. Pro- coveiT*
feffor Mufchenbroeck and his friends, obferving that
eletlified bodies, expofed to the common atmofphere,
which is always replete with conducing particles of
various kinds, foon loll their eleftrcity, and were ca¬
pable of retaining but a fmall quantity of it, imagined,
that were the eledfric bodies terminated on all fides by
original eledtrics, they might be capable of receiving a
ftronger power, and retaining it a longer time. Glafs * PrijUey,
being the moll convenient electric for this purpofe, and
water the moft convenient non-ele£tric, they firft made pr0g°Jfp ve
the;e experiments with water in clofe bottles *. improve-
For a long time water and fpirit of wine were the ment of the
only conductors employed in this experiment j but it ' >‘fen
O
was
phml.
674 K L E C T
Pi inaplc^ of was foort found by DrWatfon, that the experiment fuc-
Eledlrieity cee(ieJ better wlien the outfide of the glals was coated
iiluftrated
bv experi¬
ment.
ioi
Electrical
battery de- injJS
f. ribcd.
with foine metallic leaf, as fheet-lead, or tin-foil, while
the phial contained fome water within 5 and alter this
there was a natural tradition to the ule of an internal
as well as external metallic coating, and thus the Ley¬
den phial was completed inks prelent form (p).
A number of coated jars having their internal coat-
conne&cd together by metallic wires, conilitute
what is called a lottery. rig. 14. reprefents an elec¬
trical battery of the mod approved form, containing
nine jars. The bottom of the box is covered with tin-
foil to conned! the exterior coatings •, the indue coat¬
ings of the jars are connedted by the wires a b c, dcf,
g )i /, which meet in the large ball A a ball B pro¬
ceeds from the infide, by which the circuit may be con¬
veniently completed. In one fide of the box, near the
bottom, is a hole through wdiich a brals hook pafles,
and which communicates with the metallic lining of the
box, and ccnfequently with the outfide coating of the
jars. To this a wire or chain is occafionally connedled
when a difcharge is made •, and for the more conveni¬
ent making of this difcharge, a ball and wire, B, pro¬
ceed to a convenient diitance from the centre ol the ball
A. When the whole force of the battery is not re¬
quired, one, two, or three jars may be removed, only
by prelbing down the wires belonging to them, until
their extremities can flip out of their refpedlives holes
in the brafs ball, and then turning them into fuch a
pofture that they cannot have any communication with
the battery. The number of jars reprefented in this
iigure is rather fmall for fome purpofes ; but it is better
to join two or three fmall batteries, rather than have a
lingle large one,' which is inconvenient on account of
Tc2 its weight and unwieldinefs.
Diredtions As coated jars form one of the mod expendve parts
for the cor.-0f an eledlrical apparatus, it is of confequence that the
ftrudhon of eledlrician Ihould himfelf be able to adjud them for
tars arc experiment, and repair the coating, &c. when injured.
We diall therefore give particular diredlions for the
preparation of jars and batteries. the circumdances
neceffary to be attended to, refpe£t principally the
form of the coated eleftric, the fubdance employed
as an eleftric, and the conductor employed as a coat-
ing.
For mod experiments the bed form is that of a cy¬
lindrical jar, in which the mouth is large enough to
admit the introduction of the hand. A phial of this
form is much more eadly coated, cleaned, or repaired,
than one of any other form. Mr Cuthbertlon ufed to
make his jars entirely cylindrical, but now heis of opinion
that it is better to have the mouth a little contracted,
and he has of late always made his jars of this latter
form. For illudrating the theory of coated electrics,
as we (hall fee hereafter, plates are the mod conveni¬
ent, and they are alfo ufeful in fome experiments.
Dr Robifon prefers bottles of a globular form to any
other, and he commonly employed the balloons ufed in
batteries.
103
Form of
jars, See
It I C I T Y. Partin.
didillation, which he fays make excellent jars. The Principles of
bottles employed for holding mineral acids alio make FUAr.xity
very good jars, but they are rather inferior to the bal- ^lulr;Lte^
loons, as having very thick bottoms. For ordinary 'n(r.t "
purpoies, where a glais-houfe is at a great didance, 1 —»
common green glals bottles or apothecary’s phials
with the mouths as wide as podibie, will aniwer very
well.
With refpecl to the elecliic employed for this pur- f _
pofe, glals is to be preferred on many accounts, anebof
this the bell kind, as Hint or ciyftal : but the expence
here becomes a very condderabie object, efpecially as
the jars of a battery are very apt to break by reafon of
the inequality of their ftrength 5 for it diould feem that
the force of the eleblvic power in a battery is equally
didributed among all tire bottles, without any regard
to their capacities of receiving a charge dngiy conlider-
ed. Thus if we exprels the quantity of charge which
one jar can eadly receive, by the number 10, we ought
not to connecd Inch a jar in a battery with one wlrofe
capacity is only 8 5 becaufe the whole force of eleblricity
expreffed by 1 o will be dirccled alio againd that whole
capacity is only 8, fo that the latter vsrll be in danger
of being broken. It will be proper, therefore, to
compare the bottles with one another in this relpebt be¬
fore putting them together in a battery. Bcirdes the
condder ation of the ahlolute capacity which each bottle
has of receiving a charge, the time which is taken up
in charging it mud alfo be attended to, and the jars of
a battery ought to be as equal as pofiible in this refpecl
as well as the former. The thinner a glafs is, the more
readily it receives a charge, and vice verfa ; but it
does rrot follow from thence, as was formerly imagined,
that on account of its thinnefs it is capable of contain-
ing a greater charge than a thicker one. The reverfe
is aclually the cafe j and though a thick glafs cannot
be charged in fuch a drort time as a thin one, it is
neverthelefs capable of containing a greater degree
of eleftric power. In Fad!, if the glafs be thinner
than one-eighth of an inch, the phial will not bear any
condderable charge. If the thicknefs of the glafs be
very great, no charge can indeed be given it j but ex¬
periments have not yet determined how great the
thicknefs mud be which will prevent any charge. In¬
deed it is obferved, that though a thick glafs cannot be
charged by a weak eledlrical machine, it may be fo by.
a more powerful one, whence it feems reafonable to fup*
pofe that there is no real limit of this kind 5 but that if a
machine could be made fufficiently powerful, glades of
any thicknefs might be charged.
Glafs is attended with one ccnfiderable inconveni¬
ence ; that it is very apt to attradl moidure, and there •
fore the jars acquire perpetual care in wiping before
they are ufed •, and this, when a large battery is em¬
ployed, becomes a very troublefome operation. It is
the uncoated part of the jar which is injured by the
moidure, for it is found, that if the coating be moid,
the jar is more eafily and more completely charged.
Eledtricians
(p) Dr Watfon was indebted for the hint of a metallic coating to Dr Bevis, who was alfo the fird eledfrician
that employed a plate of glafs coated on both ddes in performing the experiments with coated eledlrics. Hence
the coated plate is often called, efpecially by the continental eledlricians, Bevis’s plate, or fquare, le carreau de
Bevis,.
very
Chap. IH. E L E C T
principles of Hletfricians have often endeavoured to find fome
Elcdlricity other eleiSlric which might anfwer better than glafs for
illuftrated thjs purp0fe) at leaft be cheaper j but except Father
byment.n~ Beccana’s method, which may be ufed very well, no
* v 1 remarkable difcovery has been made relating to tnis
105 point. He took equal quantities of very pure colopho-
Subftitute njum and powder of marble fifted exceeding fine, and
for glafs by kept them jn a hot place a confiderable time, where
eccaria' they became perfectly free from mcifture j he then
mixed them, and melted the coihpofition in a.proper
veffel over the fire, and wdren melted, poured it upon
a table, upon which he had previously ftuck a piece of
tin-foil, within two or three inches of the edge ol the
table. This done, he endeavoured with a hot iron
to fpread the mixture as equally as poffible, and to
the thicknefs of one-tenth of an inch all over the table ;
he afterwards coated it with another piece of tin-foil,
reaching within about two inches of the edge of the
mixture •, in Ihort he coated a plate of this mixture as
he would a plate of glafs. This coated plate feems,
from what he fays, to have had a greater power than a
glafs plate of the fame dimenfions: even when the
weather wyas not very dry, and if it is not liable
to be eafily broken by a fpontaneous difcharge, it may
be conveniently employed in place of glafs} for it does
not very readily attra£l moiifure, and confequently may
hold a charge better and longer than gla&, befides
when broken, it may be again repaired by means of a
hot iron, wdrereas a broken plate or veiTel of glafs can
feldom be employed again.
Talc, or Mufcovy glafs, is one of the moll convenient
eledlrics for the purpcies of coating. It is not very
apt to contraft moiilure, and will retain a charge for a
very confiderable time.
A very convenient portable phial may be conftrudled
of fealing wax in the following manner : Procure a
phial made of tin-plate, or white-iron (as it is called
in Scotland), with a long neck j cover the outfide of
this phial with fealing wax as far as the neck, and coat
the fealing wax to within a little of the neck with tin-
foil. In this phial it is evident that the fealing wax is
the electric, of which the tin-foil forms the outer and
the tin-plate the inner coating.
When plates or jars having a {Sufficiently large open¬
ing are to be coated, the belt method is to coat them
with tin-foil on both fides, which may be fixed upon
the glafs with yamifh, gum water, bees wax, &c. •, but
in cafe the jars have not an aperture wade enough to
admit the tin-foil, and an inllrument to adapt it to the
furface of the glafs, brafs filings, fuch as are fold by
the pin-makers, may be advantageoufiy ufed ; and thefe
may be ftuck on with gum water, bees wax, &c. but
not with vamilh, for this is apt to be fet on fire by the
difcharge. Care mull be taken that the coating do not
come very near the mouth of the jar, for that will
caufe the jar to difcharge itfelf. If the coating is about
two inches below the top, it wall in general do very
well; but there are fome kinds of glafs, efpecially tin¬
ged glafs, that when coated and charged have the
property of difcharging themfelves more eafily than
others, even when the coating is five or fix inches be¬
low the edge.
It is much more difficult to coat ve Jels of a globular
form than plates or cylindrical jars ; but the former may
be coated with tolerable eafeby attending to the method
106
Talc a
good elec
trie tor
coatms
107
Method of
coating
plates and
jars.
R I C 1 T Y. 675
of cutting the tin-foil. This fhould be cut into the Principles of
form of guffets as in covering a globe or in making
a balloon •, and they fhould be palled on, fo as to over- ^ expert-
lap each other about half an inch. After having coat- ment,
ed the fides of a balloon in this manner, the bottom is 1 
to be covered with a circular piece of tin-foil. Fhe
thinner the foil, the better it is adapted for the infide
coating j and it may readily be applied by firft palling
it upon paper, and then palling either the paper or the
foil next the glafs.
In co-ting plates of glafs it is better to cut the tin¬
foil “into circular pieces, as it is found that a circular
fpace is capable of giving as great a charge to the glafs,
as a fquare coating of the fame breadth, and a fpon¬
taneous difcharge does not fo readily take place from
the circular edge, as from the edges of a fquare coat-
M I0*
Mr Brooke difeovered, that when jars were coated ^,oke.s
with tin-foil firft palled upon paper, they were render- mode of
ed much lefs liable to be broken by the difcharge. As coating,
the trials which led to this difcovery afford a ufeful lef-
fon to the young ele£lrician, wre lhall relate them in his
own tvords.
“ In making electrical experiments, and in particular
thofe in which the Leyden phial is concerned, a me¬
thod of preferving the bottles or jars from being ftruck
through by the electric powrer, is very defirable ; but I
do not know that it has hitherto been accomplilhed.
The number of them that have been deftroyed in many
of my experiments, have led me to various conjedlures
to preferve them : at the fame time I have been obliged
to make ufe of bottles inftead of open-mouthed jars.
And as coating the former withinfide is very trouble-
fome, it has put me on thinking of fome method more
eafy, quicker, and equally firm and good, as with tin-
foil. With refpeCl to the new method of coating, I
failed ; though fomething elfe prefented itfelf rather in
favour of the former : therefore, introducing the pro*-
cefs here will not be of very great ufe; unlefs in
faving another the trouble of making ufe of the fame
method, or giving a hint towards the former fo as to
fucceed with certainty. My aim was to find fomething
that fnould be quick and clean, and not eafy to come
off with the rubbing of wires againft it, and yet a good
conductor. My firft effay was with a cement of pitch,
rofin, a.nd wax, melted together j into which, to make
it a good conduClor, I put a large proportion of finely
lifted brafs filings. When this mixture was cold, I
put broken pieces of it into the bottle, and warmed
the bottle till it was hot enough to melt the cement in
it fo as to run, and cover the bottle withinfide 5 then I
coated the outfide with tin-foil, as is commonly done,
and nowT it wras fit for ufe or ready to be charged, to
which I next proceeded; and I believe I had not
made more than four or five turns of the winch, before
it fpontaneoufiy ftruck through the glafs with a very
fmall charge. I then took off the outfide coating, and
Hopped the fraclure with fome of my common cement,
after which I put the coating on igain ; and in as little
time as before, it was ftruck through again in a differ-.
ent place j and thus I did writh this bottle five or fix
times ; fometimes it ftruck through the glafs in four
different places. This made me confider what it might
be that facilitated the fpontaneous linking through the
glafs, and likewife v/hat might retard it. I had, long
4 Q 2 befortq
676 ELECT
Principles of before, thought that jars or bottles appeared to be
flluftmed ^1UC^ t^roug^ a much lefs charge, juft after their
by experi- coated, or before they were dry, than when they
ment. had been coated long enough for the moifture to be
* v 1 evaporated from the pafte, with which I moftly lay on
the tin-foil, and could only confider the dry pafte as a
kind of mediator between the tin-foil and the glafs, or
in other words, that the moifture in the pafte was a bet¬
ter condudfor and more in adhral contadf with the glafs
than the pafte itfelf when dry. And the coating the
bottles with the heated cement, though long afterward,
did not alter my former idea 5 for it appeared as if the
hot cement, with the conducing fubftance in it, might
be ftill more in adhial contaft with the glafs than the
moifture in the pafte. On thefe probabilities I had to
confider what might aft as a kind of mediator more
effeftually than the dry pafte, between the glafs and
the tin-foil. It occurred, that common writing paper,
as being neither a good conduftor nor infulator, might
be ferviceable by being firft pafted fmoothly to the tin-
foil, and left to dry. The paper then being pafted on
one fide, having the tin-foil on the other, I put them
on the glafs together with the tin-foil outward, and
rubbed them down fmooth. This fucceeded fo well
that I have never fince had any ftruck through that
were thus done, either common phials or large bottles,
which contain near three gallons each, though fome of
the latter have flood in the battery in common ufe
with the others for a long time. And as I have
never had one ftruck through that has been prepared
in this way, I am much lefs able at prefent to tell
how great a charge they will bear before they are
ftruck through, or whether they will be ftruck through
at all
The mineral acids ferve very well for an infide
coating to jars 5 but their ufe is attended with fome rilk,
from their corrofive quality.
The wire through which the charge is made, fhould
not be lefs than the fourth of an inch in diameter j
it fhould be tenninated by a metallic ball, at leaft one
inch in diameser.
If the phials be intended to be frequently removed
from one place to another, the charging wire mull be
faftened fo as to be always fteady in the centre of the
phial. For this purpofe, fome employ a piece of wood,
to fit the mouth of the phial like a lid, but the length
of infulation which feparates the coating from the
phial is thus diminifhed, and confequently, as we fhall
fee hereafter, the phial is more liable to a gradual
fpontaneous difcharge, fo that it is much more diffi¬
cult to charge it. The wire is bell faftened below the
edge of the inner coating, and in this way Mr Cuth-
berefon conftrufts his jars, the mouth being left entirely
open.
When the phial is not to be removed from the fitua-
tion in whch it is charged, the wire may be faftened to
the conduftor.
Batteries may be formed either of plates or jars.
A very compendious battery may be made in the fol¬
lowing manner. Seleft a number of plates of the bell
crown glafs that are very flat and thin 5 coat them on
each fide with a circular piece of tin-foil pafted in
the middle of the plate, fo as to leave a margin fuf-
ficiently wide to prevent a fpontaneous difcharge ; let
a narrow flip of tin-foil pafs from the circumference of
* Broole's
XAifctlla-
neous Expe¬
riments and
Obferva-
tions.
ICQ
Direftions
for fixing
the wire,
&C.
no
Conftruc-
tion o’ ba
teries.
R I C I T Y. Fart III.
the coating on each fide, and lay the plates upon each Principles of
other fo that thefe flips may coincide. Let the flips be Ekdlricity
connefted at their ends by a wire which touches !lluftratecl
them all ; then if one of thefe flips be connefted
with the prime conduftor, and the other with the ' y—■—>
ground, the whole may be charged or difeharged to¬
gether. II we wilh to have a number of thefe plates
connefted fo as to form a perpetual battery, they
may be cemented by covering the tin-coated margins
wdth melted pitch, and preffing the plates down on each
other while the pitch is foft till the coatings touch
each other. But il we defire to make ufe only of a
lew of the plates at a time, and to vary their num¬
ber, they may be placed upon their edges in an open
frame; and when we wilh to make a break in the
chain of plates, this may eafily be done by placing one
of them at right angles to the reft.
A very convenient battery may be formed in this
way with coated plates of Mufcovy glafs ; but great
caution is neceffary in the ufe of liich plates, as they
are very eafily broken by a fpontaneous difcharge, and
it is not eafy to difeover where the crack has happen¬
ed.
Mr Brooke of Norwich, conftrufted his batteries, Mr
which appear to have been very powerful, of green Brooke’s
glafs bottles. Some of them, like that reprefented inmode°f
the figure, had only nine of thefe bottles : but when a fon^u^,:-
greater power was wanted, more were added. Jars teries.
would have been preferred to bottles, on account of
their being more eafily coated by reafon of their wide
mouths j but being lefs eafily procured, he was content
to put up with this inconvenience. The mean fize
of thefe bottles was about eight inches in diameter $
they were coated 10 inches high, and made of the
thickeft and ftrongeft glafs that could be procured,
weighing from five pounds and a half to feven pounds
each. In the conftruftion of a battery of 27 bottles,
he difpofed of them in three rows nine of the ftouteft
and beft compofing the firft row, nine of the next
in ftrength being difpofed in the fecond, and the third
containing the nine weakeft. All of thefe were of
green glafs, but not of the fame kind. Some of thofe
which flood in the foremoft row, wTere compofed of a
kind very much like that of which Frontigniac wine
bottles are made j and our author remarks, that this
kind of glafs feems to be by much the beft, as being
both harder and ftronger, and lefs liable to break by
a high charge. The fecond and third rows of the bat¬
tery confifted of bottles wffiofe diameter was from fix
and a half to ten inches, and which were coated
from eight and a half to eleven inches high j none of
their mouths being larger than an inch and a half, nor
lefs than three quarters of an inch.
All the bottles of this battery, as well as the Angle
ones wffiich he commonly made ufe of in his experi¬
ments, were coated both on the infide and outfide with
flips of tin-foil from three-eighths to three-fourths of
an inch wide, laid on with pafte of flour and water, at
the diftance of about a flip between each.
Mr G. Morgan lays down the following requifites jvfr Mor¬
as effential in the conftruftion of a battery. gan’s rules
1. Its connefting wires fhould be perfeftly free fromtor the con-
all points and edges. ftrudLon of
2. The connefting wires fhould be eafiily moveable,
fo that when accident has leflened the number of phials,
the
Chap.
III. ELECT
Principles of the number of wires may be reduced *fo as to corre-
Elefhicity fp0nd -with the remaining quantity of glafs.
illuftrated 1 ^ The phials ihould not be crowded } for in fuch a
ment n~ cale> necelhty Ihould oblige us to employ phials of
i ^ different heights or lizes, the tin-foil of the higher ones,
being in contact with the uncoated glafs of the lower
ones, the infulation will thus be rendered lefs complete.
4. The fize of the phials Ihould not be large *, for
though an increafe of magnitude leffens the trouble of
cleaning, it at the fame time increafes the expence of
repairing damages which frequently occur.
5. The feveral wires Ihould be fixed very fteadily,
or in fuch a manner as not to admit of any {halting.
6. The battery Ihould take up the leaft pofiible
room *, for as it increafes in fize, fo is the probability in-
creafed of its being expofed to the infiuence of fur-
t T rounding conductors.
Origin of The firft eledtrical battery appears to have been con-
the eledtri- ftruCted in the year 1746 by Mr Gralath, a German,
cal battery. j)r Franklin conltructed a battery confifting of eleven
plates of common window glafs, and with this he made
moil of the experiments which will be mentioned here¬
after. The conitruction of the battery was greatly im¬
proved by Dr Prieftley, who formed them of confider-
able fize and power. In his hiftory he defcribes and
figures one confifting of fixty-four jars, each ten inches
high, and two inches and a half in diameter, and the
whole battery containing 3 2 fquare feet of coated fur-
114 face.
Van Ma- But the moft complete electrical batteries are thofe
rum’s bat- made by Mr Cuthbertfon for Teyler’s mufeum at Haar-
ter>r' lem. Of thefe batteries there are two, differing in their
magnitude and mode of conftruction, but allowed to be
equally perfedt. The firft was completed in the year
1784, and is compofed of 135 jars in nine boxes, which
may be ufed feparately or combined, as the nature of
the experiment requires. Each box is a feparate bat¬
tery of itfelf; and the defcription of one box will be
fufficient for explaining its conftruCtion and ufe. Each
box contains 15 jars*, each jar is 11 inches high, and
fix inches in diameter, contracted at the mouth to four
inches, and coated fo as to contain 140 fquare inches }
and thus the w’hole battery will contain about 132
fquare feet of coated furface. Each box is divided in¬
to 15 partitions, five of which are in the length and
three in the breadth ; the height of the fidcs of the box
being fomewhat lower than the coating of the jars, as
are alfo the partitions in which they ftand. The lid of
the box is made without hinges, for the convenience of
releafing it from the box, that it may be removed while
experiments are performed. It is taken off by lifting
it upwards. The outfide coatings of the jars are con-
neCled by means of crofs wires pafling under the bot¬
tom of each jar *, and thofe on the inside by means of a
brafs frame, bearing 15 brafs balls, fixed upon the
frame above the centre of each jar. All thefe bells,
excepting the four at the corners, have wires fcrewed
to them and hanging downwards into the infide of each
jar *, but the wires of the four corner iars are fcrewed
to a foot, which is cemented to the bottom of each in
the made. Upon thefe wires the whole frame refts,
and is kept in its proper pofition. The four corner
balls have holes, which receive the ends of the wires,
and terminate at a proper height from the jars. By
this contrivance the infide connecting frame may at any
R 1 c 1 T Y.
677
cracked
jars.
time be eafily removed. It is according to the above Principles of
conftrucHon that Mr Cuthbertfon forms his prefent
batteries, excepting that he has increafed the fize of experi-
thejars, fo as to make one battery contain about 17 ment.
fquare feet 5 and he engages to prove by experiment, —y—J
that the batteries of his conftrudlion are far fuperior to
any others. Teyler’s fecond grand battery was finifti-
ed by Mr Cuthbertfon in 1789. This is the largeft
and moft complete battery that was ever made. It
confifts of 100 jars of the fame ihape with that of
thofe already defcribed, only that they are fo enlarged
in fize, that each of them contains 5! fquare feet of
coated furface, inftead of 140 inches, and the whole
battery contains 550 fquare feet of coating 5 and for
conveniency, it is put into four feparate cafes, each
containing 25 jars in the form of a fquare, five on each
fide. The boxes are lined with lead on the infide for
forming the outfide communication *, each jar has a
perpendicular ftand retting upon its bottom, and fup-
ported from falling lideways by three ftays on the in.
fide. Upon the top is fcrewed a three-inch brafs globe,
from which proceeds a brafs tube about one inch in
diameter, t£ a large brafs globe, fupported by the mid¬
dle jar at a proper height, fo as to keep the infide com¬
munication properly arranged. 115
Various expedients have been thought of to repair Method of
jars when cracked, and enable them to bear another reIJa.irin§
charge, but they feem to have been attended with very
little fuccefs. Mr Brooke found that when any of hisJ
bottles was broken by the difcharge, it might be con¬
veniently mended and made ferviceable in the follow¬
ing manner. “ Take of Spanifti white, eight ounces j
heat it very hot in an iron ladle, to evaporate all the
moifture *, and when cool fift it through a lawn fieve }
and three ounces of pitch, three quarters of an ounce
of rofin, and half an ounce of bees wax j heat them
all together over a gentle fire, ftirring the whole fre¬
quently for near an hour j then take it oft the fire, and
continue the ftirring till it is cold and fit for ufe.” The
bottles cemented with this compofition, however, were
not judged to be fufticiently ftrong to ftand in their
original place, but were removed to the fecond or third
row, as it was apprehended they could beft fuftain the
charge. Ji6
In relating the experiment of charging and difchar-Qf the dig¬
ging a Leyden phial, we have briefly defcribed the <^//^ charging
charging rod. Difcharging rods are made of various ro<k
forms and dimenfions *, fig. 13. reprefents one of the
moft common forms. It is convenient that the legs
fliould move upon a hinge, fo that the balls may be pla¬
ced at a greater or lefs diitance as occafion may require j
the extremities of the legs fliould terminate in points,
and the balls be made to fcrew on and off at pleafme.
Fig. 29. reprefents Mr Henly’s univerfal difcharger
an inftrument of very extenlive ufe in forming commu-lyN uni-
nications between jars, or direfHng.the ihock through ve| fd dif-
any particular fubftance. AB is a flat board fifteen c*urSer*
inches long, four broad, and one thick, and forming
the balls of the inftrument. DC are two glafs pillars
cemented in two holes upon the board AB, and fur-
nilhed at their tops with brafs caps *, each of which has
a turning joint, and fupports a fpring tube, through
which the wires EE and ET Aide. Each of thefe caps
is compofed of three pieces of brafs, conne<?ed v ith
each other in fuch a manner, that the wire EE, belides
its
<678
ELE CTRICIT Y.
Part III
tliroupli the focket.
has two other motions,
Each of the
end, and at
it8
Mr Mor-
Frinciples ofits Aiding tmoug
vj2> a horizontal one, and a vertical one
by expe l WI"res fumiftied ■with an open ring at on
ment. the other has a brafs ball $ which, by a Ihort fpring
* i— v-— focket, is flipped upon its pointed extremity, and may
be removed from it at pleafure. HG is a circular piece
of wood five inches diameter, having a flip of ivory in¬
laid on its furface, and fumiflied with a rtrong cylindrical
foot, which fits the cavity of the focket I. This focket
is fixed in the middle of the bottom board, and has a
fcrew at K •, by which the foot of the circular board is
made fall at any required height.
Fig. 30. is a fmall prefs belonging to this inftrument.
It confilts of two oblong pieces of wood, which are
forced together by the two fcrews, a, a. The lower
end has a circular foot equal to that of the circular ta¬
ble H. When this prefs is to be ufed, it muft be fixed
into the focket I, in place of the circular board HG j
which in that cafe is to be removed.
Mr G. Morgan gives the following rules for the
gan’s rules conftrudljon and ufe of difcharging inftruments.
fhi ft in"- a 1' ^iey ^10u^ be conftrufted fo as to f How no other
difchargieg t0 the eleflric power, than that of the intended
rod. " ° circuit.
2. The conducing wires of the inftrument fhould be
made to come into contadl with the inner furface of the
coated eledlric as fpeedily as poflible; for when ap¬
proached gradually part of the charge is taken off pre¬
vious to the explofion, the power of which is thus
greatly diminifhed.
3. The operator fliould not be within the atmofphere
of the conduftor at the time of making the difcharge.
4. The difcharging inftrument and the infide of the
charged furface Ihculd be feparated as rapidly as they
no were connefled.
His difchar- Qn thefe principles the inftrument employed by Mr
gmg rod. ]\/[organj in his experiments on the conducing power
of various fubftances, is conftrudted, and is thus defcri-
bed by him.
A and B, fig. 31. are two brafs wheels, whofe dia¬
meter is four or five inches j they are connedled by an
axis, which is made to turn eafily in a collar, fixed up¬
on the glafs ftem DM. The wires DC, and EF, are
fcrewed into the circumference of the wheels, but on
fides direftly oppofite to each other. Ihe length of
thefe wares is regulated by the diftances at which the
difcharging rod is fixed from the conducing body, and
their diredlion is perpendicular to the axis of the wheels.
Twto other wires are to be fixed perpendicularly to the
planes of the wheels, to the circumference of which
they are fcrewed as nearly as poflible, but at oppofite
points, fo that they may ftrike obi eels lying in the fame
line, parallel to the axis at the diftance of half a revo¬
lution from each other. I he length of thefe laft wires
is regulated by the diftances at which they join the
metallic or other connexion that is formed with the
outfide of the coated phial.
The mode of ufing this difcharging rod is as follows.
When C is brought into contacl with the condudlor, it
receives the eledlric power, and conveys it through G
into the outfide of the coated furface. The motion of
C is not flopped by the contacl, but the continuance of
it brings E into the fame contaft by which the refidue
of the jar is conveyed through K to the outfide. The
glafs ftem {hould penetrate deeply into each of the caps,
4
for the whole apparatus will be otherwife loofened and Piinciplesot’
put out of order, by the neceiTary rapidity of the mo- Ekftn'city
tion and the conquaflation of parts attending it. illuftrated
t* • • -T • ^ •! • py exueri-.
It C, m its circumvolutions, ftnxe againft an im- ment.
moveable body in connexion with the conductor, it is > v——.
frequently flopped, and then its ball is injured, or a
change unfavourable to the accuracy of the experiment
takes place.
To prevent thefe inconveniences, C, fig. 32. ftrikes
the ball A which is connedled with the brafs tube that
penetrates into the conducting fubftance, with an elaf-
tic wire bent into the form of a fpring. The points
and edges of this inftrument are rendered impotent by
faftening a box to the brafs tube, fo that the ball A
may move backwards and forwards in the hollow of it,
when ftruck by C. The box Ihould be made of hard
wood, and its edge carefully turned and well polilhed. 120
When a coated jar has been difeharged, either Cautions,
fpontaneoufly, or by a difeharger, there is ftill a por¬
tion of the charge remaining, fufficient to give a flight
ftiock, as will be found by grafping the outfide with
one hand, and with the other touching the ball of the
ware. As this remaining charge, eipecially in large
jars or batteries, is often fo conliderable as to give a
pretty fevere ftiock, it is therefore proper to caution
the experimenter, not to touch the outfide of the jar
or battery, or any conductor which communicates with
the infide at the lame time.
Every machine will not charge jars equally well, but
the power of charging will depend much on the good-
nefs of the cylinder.
In a battery it fometimes happens, that one or more
of the jars is more apt than the reft to undergo a fpon-
taneous difcharge, and in this cafe, the wdiole of the
battery wall be difeharged at the fame time, although
the other jars, without this accident, wrould have con¬
tained a much higher charge. I2
To remedy the inconvenience of fome of the jars inMrNairne’s
a battery burfting at the time of the difcharge, Mr mode ot
Nairne propofed that the difcharge Ihould not be madePrev.ent'n?
through a perfedf conductor of a fhorter circuit than a battery
five feet 5 and this method he found fo effeftual, that from bemg
after he adapted it, he wTas able to difcharge a battery broken by
for a hundred times without breaking a Angle jar,a difchaige.
which before was continually happening. It muft be
obferved, how’ever, as will appear foon, that when the
circuit through which the difcharge is made, is confix
derably lengthened, the force of the difcharge is alfo
proportionably diminilhed. Hence in many experi¬
ments, where it is neceffary to employ the higheft pof-
fible charge, this method of diminilhing the rilk of
breaking the jars is inadmiflible. 122
If a Leyden phial, or any other coated eleBric, be in- An infula-
fulated or placed fo that its external coating has no com- ted phial
munic at ion with conducing bodies, it cannot be charged. cf‘nr}0t ,be
Place a Leyden phial on the infulating ftool, or on 1 0
a wine glafs turned mouth downwards ; conned! the
knob of the jar, or its outfide coating, with the prime
condudtor, by means of a chain, and let the machine in
motion. It will then be obferved that the quadrant
electrometer on the knob will foon rife to 90°, feem-
ing to indicate that the jar is charged. On taking off
the connedlion between the jar and the prime conduc¬
tor, a?id endeavouring to difcharge the jar by means of
the difcharging rod, or by the hands, it will however
appear
Chap.
HI. ELECT
principles of appear that the jar has received only a very flight
EleAricity charge, as no confiderahle fpark will ftrike the ball of
illuitrated ^ c^rc^argjng and no remarkable fhock will, be
^ment. felt by the hand.
w—v  If now the outfide of the jar, ftill Handing on the
infulator, be conne&ed with the floor, table, &c. by a
chain, and then charged, the refill will be very dif¬
ferent as the jar will then receive its ufual charge.
If a jar be infulated, and one fide of it, inftead of
being conneded with the earth, be connected with the
infulated rubber, while the other fide communicates
with the prime conductor, the jar will be charged,
and perhaps in a more expeditious manner.
To make the above experiment in a clearer and more
fatisfadory manner, place the jar upon the ftool as before,
and with its wire not in con tad, but at about half an
inch difiance from the prime condudor j hold the knob
of another wire at fuch a difiance from the outiide
coating of the jar, as the knob of the jar is from the
prime condudor, then let the winch of the machine be
turned, and it will be obferved, that whenever a fpark
comes from the prime condudor to the wire of the jar,
another fpark paffes from the outfide coating of the jar
to the knob of the wire prefented towards it. In this
manner the jar becomes charged.
If inftead of the knobbed ware, a pointed wire be
prefented to the outfide of the jar, the point will ap¬
pear illuminated with a liar; and if inftead of pre-
fenting any wire to the jar, a point be conneded wuth
its coating, the point will appear illuminated with a
brulli of rays which will laft as long as the jar is
charging.
If the knob of another jar be prefented to the out¬
fide coating of the infulated jar in the above experi-
T2, ment, it will alfo be charged.
The charge The charge of a coated jar, or any coated electric, re¬
ef a coated Jides in the jar, or electric, and not in the coating.
fide^'in the hake an uncoated phial, and, for a coating on the
eleAric. outfide, flick a piece of tinfoil with a little talkw or
bees wrax, fo that it can juft adhere to the glafs; and
for an infide coating put into the jar a quantity of fmall
Ihot or of mercury : flop the mouth of the jar writh a
perforated cork, through which infert a knobbed wire,
fo as to communicate with the Ihot or the mercury.
Then hold the phial thus coated, by its outfide coating,
and charge it by prefenting the knob of the wire to
the prime condudor. When it is charged, turn it up-
fide dowm, fo that the wire, and the mercury or Ihot
within the jar, may fall into a dry glafs veffelj then re¬
move alfo the outfide coating. During this operation
the phial does not lofe its charge; and if the Ihot or
mercury be examined, it wall be found that they are not
more eledrified than wrould happen to any other infula¬
ted body of equal conduding power, after having been
in contad with the prime condudor. Now replace the
cutfide coating on the phial, and pour into it the (hot
or mercury •, then touch wdth one hand the outfide coat¬
ing, and with the other introduce a knobbed ware with¬
in the phial fo as to touch the infide non-eledric, and
you will feel a fhock, wyhich will prove that the jar
has loft very little of its charge by removing the
coatings.
The fame experiment may be more conveniently
made by laying a pane of glafs upon a metal plate, and
It I C I T Y. 679
covering an equal part of the upper furface with tin Principles of
foil, having a lilk thread fattened to one of its fides,
by which it may be eafily taken off when the glafs is ^ e
charged, and as eafily replaced when required. ment.
This important fad, that the charge in a coated ~—r ‘
eledric refides in the eledric and not in the coating, . ,fI74
was afeertained by Dr Franklin. Qr'eref
When he firft began his experiments upon the Leyr prany;n.
den phial, he imagined that the eiedric power was all
accumulated in the fubilance of the non-eledric in con-
tad with the glafs j but he afterwards found by the
following ingenious analylis of the bottle, that the
power of giving a shock lay in the glafs itielf, and not
in the coating.
In order to find where the ftrength of the charged
bottle lay, he placed it upon glafs ; then firft took out
the cork and the wire, and finding the virtue was not
in them, he touched the outfide coating with one hand,
and put the finger of the other into the mouth of the
bottle, when the ftiock was felt quite as ftrong as if the
cork and the wire had been in it. He then charged
the phial again, and pouring out the water into an emp¬
ty bottle infulated, expeded that if the force refided
in the water it would give the Ihock, but he found it
gave none. He then judged that the eledric fire muft
either have been loft in decanting, or mufi remain in
the bottle, and the latter he found to be true ; for fill¬
ing the charged bottle with frelh wrater, he found the
fhock, and was fatisfied that the power of giving it re¬
fided in the glafs itfelf.
He made the fame experiment with panes of glafs,,
laying the coating on lightly, and changing it as he
had before changed the wrater in the bottle, and the
refult wras the fame in both. This experiment is more
fatisfadory than the former; becaufe when the wTater
is poured out of the phial, there ftill remains a thin
coating of the fluid, which might be thought to contain
the power of giving a ftiock. 125
ud charged jar may be gradually difeharged by tnahing
a conducting body communicate alternately with the out-'
fde and the infde coating. 126
Experiment 1.—Fig. 33. reprefents an eledric jar, [ke else-
having a wire, CDF., fattened on its outfide, which isje^et1^’
bended fo as to have its knob E as high as the knob A. plate
B is the figure of a fpider formed out of a piece of cork clxxxviie,
flightly burned, with a few ftiort threads run through
it to reprefent its legs. This fpider is to be fattened at
the end of a filk thread, proceeding from the ceiling of
the room, or any other fupport, fo that the fpider may
hang midway between the twTo knobs AE, when the
jar is not charged. Let the place of the jar upon the
table be marked j then charge the jar, by bringing its
knob A in contad with the prime condudor, and re¬
place it in its marked place. The fpider will now be¬
gin to move from knob to knob, and continue this
motion for a confiderable time, fometimes for feveral
hours.
This experiment is one of the earlieft that were
made by Dr Franklin and his friends, and is deferibed
by Dr Franklin in one of his letters to Collinfon.
Exper. 2.—Let a coated jar be infulated by pafling
it through a ring fixed upon a glafs ftand, as reprefent-
ed at fig. 34. From the ball a of the wire which com¬
municates with the infide coating fufpend a wire to
which
illuftratcd
fey experi¬
ment.
. I27
Lateral ex-
plolion.
680
Principles of which are hung tlirce bells and two clappers, and fu-
tilurtrah*! ^Penc^ a ^m^ar wire with the fame number of bells and
clappers from the ball, of a wire which is made to
communicate with the outfide coatingi Hang the
chain q to the wire rz, fo that it does not touch the
table, and charge the jar by holding the knob a to the
prime conduflor. Tv'llile the jar is charging, the bells
hanging from b will ring. When the jar is charged,
remove it from the prime conductor, and unhook the
chain g, by means of a wire failened to a glafs handle,
and let it lie on the table* If now the ball b be touch¬
ed, the bells which are fufpended from it will ceafe
ringing, and the bells fufpended from a will ring, and
will continue to ring for a conhderable time if not
touched. But, now again, if a be touched, thefe bells
will ceafe, and thofe at b will begin to ring, and thus
each fet may be made to ring alternately, but never
both fets at once till the bottle is difcharged.
If a jar be difcharged with a difcharging rod that
has no eleftric handle, the hand that holds'it, in making
the difcharge, feels fome kind of fhock, efpecially
W'hen the charge is confiderable.—In other words : A'
perfon, or any conducing fubftance, that is connedled
wdth one fide of a jar, but forms no part of the circuit,
will feel a kind of ihock, i. e*' fome effeft of the dif¬
charge. This may be rendered vifible in the following
manner. Conned! with the outlide of a charged jar
a piece of chain ; then difcharge the jar through
another circuit, as for inilance, with a difcharging rod
in the common way, and the chain that communicates
with the outfide of the jar, and which makes no part
of the circuit, will appear lucid in the dark, i. e. fparks
will appear between the links* This chain will alfo
appear luminous, when it is not in contadl with the
outfide of the jar, but only very near it ; and on
making the difcharge, a fpark will be feen between the
jar and the end of the chain near it. This electrical
appearance out of the circuit of a difcharging jar, is
that which we call the lateral explojton : and to make
it appear in the moft confpicuous manner, obferve the
following method, which is that of Dr Prieftley.-
When a jar is charged, and Hands upon the table as
ufual, infulate a thick metallic rod, and place it fo
that one of its ends may be contiguous to the outfide
coating of the jar •, and within about half an inch of
its other end, place a body of about fix or feven feet in
length, and a few inches in breadb $ then put a chain
upon the table, fo that one of ;ts ends may be about
one inch and a half diftantdrom the coating of the jar j
to the other( end of the chain apply one knob of the
difcharging rod, and bring the other knob to the wire
of the ]ar in order to make the explofion* On making
the difcharge in this manner, a Hrong fpark will be
feen between the infulated rod, which communicates
with the coating of the jar, and the body near its ex¬
tremity, which fpark does not alter the Hate of that
body in refpeft to ele&ricity •, hence it is imagined,
that this latetal fpark flies from the coating of the jar,
a: d returns to it at the fame inftant, allowing no per-
certible fnace of time, in which an eledrometer can
be affeded. Whether this lateral explofion is received
on flat and fmooth furfaces, or upon {harp points, the
Ipark is always equally long and vivid.
electricity.
Part III,
Principles of
Ohap. IV. Of the methods of dijlmgu 'tjhing Poftive Electricity
and Negative Hleclncity. illuftrated
•' by experi-
I hese Hates of eledricity are ufually diflinguiflied bv 1 «
means of the common pith-ball eledrometer. 128
Experiment.—Set the machine in motion, while P' fitive ani
both conductors are infulated, or without conneding e“
either the prime condudor or the rubber with contigu-
ous bodies. We have before remarked (44), that tire d the
prime condudor was called the poftive, and that toeie<arom8!i
which the rubber is adapted the negative conductor j er‘
that they are lo in thefe circumflances may be demon-
firated according to the explanation given in
note (d).
On prefenting a pith-ball eledrometer to the cylind¬
er whole eledricity we have agreed to call poftive, the
balls will diverge, and wall continue to diverge wdien
brought near that fide of the prime conductor which is
mofi remote from the cylinder ; but being carried to
the other condudor, they will inltantly collaple ; thus
fhowing that the eledricity of the rubcer is oppofite to
that of the other condudor or of the cylinder, i. e. that
it is negative. This may be Ihown m another way.
The balls prefented to the rubber will diverge with ne¬
gative eledricity, but being brought near the other
condudor in this divergent Hate, they will collapfe.
But mould a more precife method be required to
determine the quality of the eledricity of an eledrified
body, the following may be ufed :—Firfl, eledrify one
of the eledrometers C, placed upon the Hand fig. 15,
either pofitively, or negatively, at pleafure : touch it^
for inHance, with an excited glafs tube, lb that its balls
may repel, and Hand about two inches diflant from one
another ; then touch the other eledrometer C with the
eledrified body, that you defire to examine, fo that it
may be poffeffed of the fame degree of eledricity : laH-
ly, take either of the tw'o eledrometers by the top of
the glafs handle, difengage it from the arm of the Hand,
and bring it near the other eledrometer ; if then the
balls of one eledromer repel thofe of the other, you
may conclude that they are poffefled of the fame kind
of eledricity ; but if they attrad each other, you may
conclude that they have been eledrified with contrary
eledricities •, and as you know the eledricity of that
eledrometer, which was firfl eledrified, you will of
courle know the eledricity of the other eledrometer,
i* e. of the eledrified body, with which it was
touched.
The above experiment may be alfo made with the
fingle-thread eledrometers $ for if they are brought
near to one another, wTen their feathers are eledrified,
they will, if pofieffed of the fame eledricity, repel
each other, or, if poffeffed of contrary eledricities, they
will attrad each other.
While the condudors are thus infulated, if a pointed ^
body (as for inflance, the point of a needle or pin) be light,
prefented to the back of the rubber, at the diflance of
about tw’O inches, a lucid pencil of rays wall appear to
proceed from the point prefented, and diverge towards
the rubber.
If another pointed body be prefented to the prime
condudor, it will appear illuminated with a ffar 1 but
■ a1
3
Chap. IV.
ELECT
by experi
ment.
i Wilch,
p. 240.
Prinoplesotif a pointed wire, of other pointed conducting body,
Electricity be connected with the prime conductor, it will throw
nlultrated oul; a pencil Qf raySi
F. Beccaria remarks, that if two equally lharp points
are approached to a prime conductor, they will appear
luminous at only half the diltance at which one of
them would have done.
From this experiment may be learned the method of
diitinguilhing the quality of the electricity of an electri¬
fied body, by the appearance of the eledtric light 5 for
if a needle, or any other pointed body, be prefented in
the dark, with the point towards a body Itrongly elec¬
trified, it will appear illuminated with a itar, when that
body is eleftrified pofitively, and with a pencil or brulh,
when it is electrified negatively (q_).
Here it is proper to remark, that when two points
(one of which is connected with the prime conductor,
or the rubber) are oppo ed to one another, the appear¬
ance of light in both is pretty much the fame. Mr
Wilcke' remarks, that when a point not eleCtrified, is
oppofed to another point electrified pofitively, the cones
of light, which othenvife would appear upon them, dif-
appear ■, but that if a politive cone be oppofed to a ne¬
gative cone, they both preferve their own characteriltic
properties f.
Mr Nicholfon has given us fome valuable obferva-
tions on the different appealances of the electric light,
when proceeding from bodies electrified pqfitively or ne¬
gatively.
“ The efcape of negative electricity from a ball,,,
fays Mr Nicholfon, “is attended with the appearance of
ftraight lharp fparks wfith a hoarfe or chirping noifet
When the ball was lefs than two inches in diameter, it
wras ufually covered wfith fhort flames of this kind,
which were very numerous,
Mr Nichol- “ When two equal balls w’ere prefented to each
fon’s expe- other, and one of them wTas rendered Itrongly politive,
riments on wbile the other remained in connexion with the earth,
the light t|ie p0fltjve brulh or ramified fpark was feen to pafs
by pofitive from the eleCtrified ball : when the other ball was elec-
and nega- trilled negatively, and the ball, which before had been
pofitive, was connected with the ground, the eleCtricity
exhibited the negative flame, or denfe, ftraight, and more
luminous fparks from the negative ball; and when the
one ball was electrified p/ns and the other minus, the
figns of both eleCtricities appeared. If the interval was
not too great, the long zig-zag fpark of the plus ball
ftruck the ftraight plane of the minus ball, ufually at
the diltance of about one third of the length of the lat¬
ter from its point, rendering the other two thirds very
bright : fometimes, however, the pofitive fpark ftruck
the ball at a diftance from the negative flame. Thefe
effeCts are reprefented in Plate CLXXXVIII. figs. 35,
cx.xxxv111.36> 3nd 37* 1 ..
“ Two conductors of three quarters of an inch dia¬
meter, wfith fpherical ends of the fame diameter, were
laid parallel to each other, at the diftance of about two
inches, in fuch a manner as that the ends pointed in
onnofite directions, and w^ere fix or eight inches afunder.
Thefe, which may be diitinguilhed by the letters P and
Vol. VII. Part II.
130
live ek c-
tricity.
Plate
R I C I T Y. 63i
M, were fucceflively electrified, as the balls were fin Principle^ of
the laft paragraph. When one conductor P was pofi-
tive, figi 39. it exhibited the fparks of that eleCtricity experi-
at its extremity, and ftruck the fide of the other con- ment.
duCtor M. When the laft-mentioned conductor M v 1
W7as eleCtrified negatively, fig. 38. the former being in
its turn connected wfith the earth, the fpaiks ceafed to
ftrike as before, and the extremity of the eleCtrified
conductor M exhibited negative figns, and ftruck the
fide of the other conductor. And w hen one ccnduCtor
was eleCtrified plus and the other minus, fig. 40. both
figns appeared at the fame time, and continual ftreams
of eleCtricity palled between the extremities of each
conductor, to the fide of the other conductor oppofed
to it.
“ In drawing the long fpark from a ball of four in.
ches diameter, I found it of fome confequence that the
Item lliould not be too fhort, becaufe the vicinity of
the large prime conduCtor altered the difpofition of the
eleCtricity to efcape : I therefore made a fet of experw
ments, the refult of which Ihowed, that the difpolition
of balls to receive or emit eleCtricity, is greater when
they Hand remote from other furfaces in the fame ftatej
and that betw'een this greateft difpofition in any ball,
whatever may be its diameter, every poflible lefs de¬
gree may be obtained by withdrawfing the ball towards
the broader or lefs convex furface out of which its Item
projeCts, until at length the ball, being wholly depref-
fed beneath that furface, lofes the difpofition entirely.
From thefe experiments it follows, that a variety of
balls is unneceffary in eleCtricity : becaufe any fmall
ball, if near the prime conduCtor, wfill be equivalent
to a larger ball whofe Item is longer.
“ From comparing fome experiments made by my- Mr Nichol*
felf many years ago wfith the prefent fet, I confidered a lon’s aPP2~
point as a ball of an indefinitely fmall diameter, and ^'ichThe
conitruCted an inftrument confilting of a brafs ball of ac4jon 0f
fix inches diameter, though the axis of which a Item, points is
carrying a fine point, was ferewed. When this Item is kuftrated,
fixed in the prime conduCtor, if the ball be moved on
its axis in every direction, it caufes the fine point either
to protrude through a fmall hole in its external furface,
or to withdraw itfelf j becaufe by this means the ball
runs along the Iterm The difpofition of the point to
tranfmit eleCtricity may thus be made equal to that of
any ball whatever, from the minuteft fize to the diame¬
ter of fix inches. See fig. 41. A.
“ The effeCt of a pofitive furface appears to extend ,
farther than that of a negative ; for the point aCts like T;ranf foi
a ball, w;hen confiderably more prominent, if it bepo-^So.
fitive, than it will if negative f.” 1.3*
Fig. 42. reprefents an inftrument invented by ^r, N:iC^01"
Mr Nicholfon for diitinguithing pojitive from negative
eleCtricity. It confifts of two metallic balls, A, B, aiftmguifti-
which may be placed at a greater or lefs diftance from mg nega-
each other, by means of a joint at C, on which thet,vt fi'om
two branches CA, CB move. Thefe branches are ^
glafs covered with varniih. A ihort point proceeds *
from one of the balls B towards the other A. If the
two balls be placed near a body which is eleCtrified, fo
4 R that
(q) The pencil of light exhibited by a point pofitively eleCtrified was firft feen by Mr Grey, though the dif»
ference of the two ftates was not in his time correCtly afeertained.
682
E L E C T R I
FrindpJcs ofthat tlie ele&ric power may pafs through them, it may
ill ultra ted be kn0W1 whether it is pofitive or negative, that is,
by experi- whether it is proceedingor towards the eledrilied
merit, body. For, fuppofmg that the eledricity palfes from
' / A to B, there will be a certain diftance of the balls at
which a fpark will pafs betwTeen the balls} but this dif-
tance will be much fliorter wdien the eledfricity is paf-
fing from B to A. It is evident that this inftrument
tvill be of uie only when the eledlricity to be examined
is fufficiently ftrong to give fparks.
Appearance 1 he appearances of politive and negative elec-
of the light tricity are fufficiently dxilincl in almolt every experi-
on paper, ment which can be made with the exhibition of eledric
light. Paper is a good fubltance for obferving the vi-
lible paffage of the electric power. If a ftrong politive
eledtric ftream be let fall on the flat fide of an uninfu-
lated Iheet of paper, it wall form a beautiful Jlar about
four inches in diameter, confifting of very diltindt radii
not ramified. Negative eletftricity, in perfedtly fimilar
circumltances, throwrs many pointed bruflies to the pa¬
per, but forms no liar upon it. This experiment is by
Mr Nicholfon, and the cylinder of the machine em-
*Nhlmlfonsployed in making it was feven inches in diameter*.
Phil. Journ.
vol. ii.
P- 43s- Chap. V. Of the different fates of electricity pojfefed
by the two furfaces of a charged electric.
Tun oppofte furfaces of a charged e/eBric are in op-
134 pofite fates, i. e. one poftive, and the other negative.
Politive and Exper. 1. Infulate a coated phial, fuch as is defcrib-
ftatesof eC* *n 34* without the bells, and charge it by hold-
charged fiarinS knob a to the_ pofitive condudtor, while the
proved by hnob b communicates with the table. When the phial
the ball- is charged, hold a pith-ball eledlrometer to the knob a,
eledlrome- and the balls will diverge with pofitive eledlricity, as
will appear by prefenting them in their diverging llate
to excited fealing-wax, when they will coilapfe. Now
hold the balls to the knob b, which communicates with
the outer coating of the phial, and they will diverge
with negative eledlricity, as wall appear by prefenting
them to an excited glafs tube.
If the jar be charged at the negative condudlor,
thefe appearances will be reverfed ; the balls prefented
to the knob a- will diverge with negative eledlricity,
and prefented to b, they will diverge with poftive elec¬
ts tricity.
By the ap- Exper. 2. Fix a pointed wire into a hole in the knob
the f ffit °f^ tbe ^n^ulatecl pbial, and fix another wire in the po-
16 ‘ fitive condudlor. Hold the knob a to the point in the
pofitive condudlor, and on turning the cylinder in the
dark, a pencil of luminous rays will be feen diverging
from the point in the condudlor to the knob a, while a
fimilar pencil of rays, diverges from the wire fixed in
the knob b.
If the wire is fixed in the negative condudlor, a lu¬
minous far wall appear at each point.
Exper. 3.—Fix a pointed wire into a hole in the
knob a, while another pointed wire is fixed in b, as in
the laft experiment. Prefent the wire in the knob a in
the dark, to the pofitive condudtor, and a luminous
far will appear at the point a, while the point at b
throws out a pencil of luminous rays.
If the point at a be prefented to the negative con-
C I T Y. part m.
dudlor, the luminous pencil will appear at a and the lu-Principles of
minousfar at b. Eledlriuty
Exper. 4.—Fig. 43, is an eledtric jar which ferves to !llulirate.d
illuflrate the contrary Hates of the fides of a Leyden 'Aent
phial while charging : BE is the tinfoil coating ; C, a ' v 
ftand which fupports the jar j D, a focket of metal, carry- Plaie
mg the glafs rod EF, a bent brafs wire pointed at each crxxxtx
end, and fixed at the end of the rod G •, this rod is
moveable in the fpring tube N at pleafure : that tube
being fixed by a focket on the top of the glafs red E,
the jar is charged by the infide wire, which communi¬
cates with the different divifions of the infide coating
by horizontal wires.
1 race the jar at the condudlor as ufual j and when
charging, a luminous ftar will appear upon the upper
point of the wire at F, clearly Ihowing, accordingXto
the commonly received opinion, that the point is then
receiving the eledlric povrer. From the upper ring of
the coating B, on the outfide of the jar, a ftream or
pencil of rays will at the fame time fly off, beautifully di-
verging from the lower point of the wire E Upon the
bottom ring of the coating of the jar. When the ap¬
pearances ceafe, which they do w hen the jar is charged,
let a pointed ware be prefented to the condudtor : this
will foon difeharge the jar filently; during which the
point will be illuminated with a fmall fpark, wffiile the
upper point of the wire will throw off a pencil of rays
diverging towards the upper ring of the coating.
When a charged eleBric is difeharged, the electric Courfe of
power paffes from the poftive to the negative furface. the eledtric
Exper. 1.—When ajar has been charged at the pofi-P0Weriu
tive condudlor, take a difeharging rod, fumilhed with' j^rdli'
pointed extremities, and hold it in fuch a pofition, that(hewn|
one point fhall be at the diftance of about an inch from by tha
the knob of the jar, while the other point {hall be atlight;
nearly the fame diftance from the outfide coating. In
this wTay the jar will be filently difeharged, and if the
experiment be made in the dark, a luminous far will
appear at that point which is held to the knob of the jar,
and a luminous pencil at the point which is held to the
outer coating.
If the jar has been charged at the negative coridmCtor,
the appearance of the light at the points will be reverfed 5
a luminous pencil will now appear at the point which is
held to the knob of the jar, and a luminous far at that
wffiich is held at the outer coating.
Exper. 2.—Remove the circular piece of wmod GH, By ?hldi-
from the univerfal difeharger, fig. 29, fix the wires j EF, redtion
ET, fo that their knobs FT may be about two inches §lven to
diftant from one another. Then fix upon the focket flame .
from which the board wras removed, a fmall lighted wrax° a
taper fo that its flame may be juft in the middle betw een
the knobs FT. When the apparatus is thus difpofed,
if the outfide of a charged jar be connected by means of
a chain or other conducing fubftance, with one of the
wires, and the knob of the jar be brought to the other
wire, it will be obferved, that, on making the difeharge
which muft pafs between the knobs FT, the flame of the
taper wdll be driven in the diredlion of the eledlric
power, i. e. it will be blowm towards the knob of
that wire which communicates with that furface of the
jar which is negatively eledlrified.
Exper. 3.—Fig. 44. and 45. of Plate CLXXXIX.
reprefent a fmall phial coated on the outfide, about three
inches
Chap. V, ELECT
Principles of inches up, with tin-foil j at the top of the neck of this
Elccfricuy phial, is cemented a brafs cap, having a hole with a
byUexperi va^ve> an(^ from the cap a wire proceeds a few inches
ment. within the phial, terminating in a blunt point. When
y—■■ * this phial is exhaufted of air, a brafs ball is to be fcrew-
133 ed on the brafs cap, fo as to defend the valve, and pre-
*he vent any air from getting into the exhaufted glafs. This
cuum • phial exhibits clearly the direction of the eletftric power,
’ both in charging and difcharging j for if it be held by
its bottom, and its brafs knob be prefented to the prime
conduftor politively ele&rified, you wall fee that the
ele&ric power caufes a pencil of rays to proceed from
the wire within the phial, as reprefented fig. 45. and
when it is difcharged, a Jlar will appear in the place of
the pencil, as reprefented in fig. 44. But if the phial
be held by the brafs cap, and its bottom be touched
with the prime conductor, then the'point of the wire,
on its infide, will appear illuminated with a Jlar when
charging, and with a pencil when difcharging. If it be
prefented to a prime conductor eletftrified negatively, all
thefe appearances, both in charging and difcharging,
will be reverfed.
This experiment of the Leyden vacuum, as it is call*
ed, is an invention of the late Mr Heniy.
Exper. 4.—Fig. 46. reprefents an eledtric jar, whofe
exterior coating is made up of fmall pieces of tin-foil
placed at a fmall diftance from each other. This jar
is to be charged in the ufual manner, when fmall fparks
will pafs from one piece of tin-foil to the other, in vari¬
ous dire£Hons, forming a very pleafing fpeftacle. The
feparation of the tin-foil is the caufe of this viuble pafiage,
from the outfide to the table j and the experiment is li-
milar in appearance to that mentioned. If the jar be
difcharged by bringing a pointed wire gradually to the
knob F, the unfealed part of the glafs between the
wire and knob will be agreeably illuminated, attend¬
ed by a crackling noife of the fparks. If the jar
be fuddenly difcharged, the whole outfide will be
illuminated. The jar, uled in thefe experiments, muft
be very dry.
Exper. 5.—Fig. 47. reprefents two jars, or Leyden
phials, placed one over the other, by which various ex¬
periments may be made in order to elucidate the theory
of eleflricity. Bring the outfide coating of the bottle
A in contaft with the prime conduflor, and turn the
machine till the bottle is charged } then place one ball
of the difcharging rod upon the coating of B, and with
the other touch the knob of the jar A, an explofion
will follow ; now place one ball of the difcharger
on the knob A, and bring the other ball to its coat-
ing, and you have a fecond difcharge. Again, ap¬
ply one ball of the difcharger to the coating of B, and
carry the other to the coating of A, and it will pro¬
duce a third difcharge. A fourth is obtained by ap-
plying the difcharger from the coating of A to its
knob.
The outer coating of the upper jar communicating
with the infide of the under one, conveys the ele£!ric
power from the conductor to the large jar which is
therefore charged pofitively : the upper jar does not
charge, but when a communication is formed from the
outfide of A to the infide of B, part of the dearie
power on the infide of A will be conveyed to the nega¬
tive coating of B, and the jar will be difcharged. The
*39
By the
double jar
R I C I T Y. 683
fecond explofion is occafioned by the difcharge of the Principles of
jar A ; but as the outfide of this communicates by con-
duding fubftances with the politive infide of the jar B, by. eXper--
if the ball of the difcharging rod remains for a little ment.
time after the difcharge on the knob of A, part of the v-—
ele&ric power of the infide of A will efcape, and be re¬
placed by an equal quantity on the outfide from the jar
B, by which means A is charged a fecond time j the
difcharge of this produces the third, and of B the fourth
explofion. I40
Mr Brooke of Norwich brings the following ex- MrBrooke’j
periments to prove that the oppofite furfaces of anexPer^
eleftric, while charging, are not neceffarily in oppofite ments’
ftates of eledricity.
“ 1. Let two pound phials be coated with tin-foil on
their outlides, and filled to convenient height with com¬
mon Ihot, to ferve as a coating withinfide, as well as to
keep a wire fteady in the phials without a ftopple in the
mouth of them. Let each phial be furniflied with a
wire about the fize of a goofe-quill, and about ten inch¬
es long, and let each wire be fliarpened a little at
one end, that it may the more eafily be thruft down in¬
to the Ihot, fo as not to touch the glafs anywhere at the
mouth of the phials, yet fo as to Hand fteadily in them.
Let a metallic ball about fix or feven eighths of an inch
diameter be ferewed on at the other end of each wire :
alfo, let there be in readinefs a third wire, fitted up like
thole for the phials, except that another ball of nearly
the fame fize as the former may occafionally be ferewed
on at the lharpened end of it. I fay, inftead of fuf-
pending the phials from the prime condudor, let one of
thole above deferibed be charged at the prime conduc¬
tor, and then fet it afide, but let it be in readinefs in
its charged ftate ; then let the other be placed upon a
good infulating Hand, and let the third wire alfo be laid
upon the Hand, fo that its ball, or fome part of the wire,
may touch the coating of the phial. Let the lharpen¬
ed end of this wire projed five or fix inches over the
edge of the Hand ; all of thefe being now placed clofe
to the edge of a table, hang a pair of cork balls on the
lharpened end of the wire* and make a communication
from the prime condudor to the ball on the wire on the
bottle.: on working the machine, the lharpened end of
the wire will permit the bottle to be charged although
it be infulated ; and if the wire be very finely pointed,
the bottle may be charged nearly as well as if it wTere
not infulated : I fay, on working the machine, the phial
will charge, and the cork balls will immediately repel
each other ; but whilft this phial is charging, take the
firft phial, which having been previoufly charged at the
fame prime condudor in the hand, and while the fecond
phial is charging, prefent the ball of the firft to the
cork balls, and they will all repel each other. This
plainly proves that the outfide of the fecond bottle is
eledrified plus at the time that it is charging, the fame
as the.infide of the firft ; and the infide of both the bot¬
tles will readily be allowed to charge alike, that is plus
or pnjitive.
^ 2. Lee the fecond bottle in the laft experiment be
wholly difcharged, and charge it again as before (the
firft bottle yet remaining charged) \ and whilft it is charg-
ing, let the ball of the firft apprcv.ch the cork balls con¬
tiguous with the fecond, and they will, as before, all re¬
pel each other ; withdraw the ball of the firftr and fo
4^-2 long
illaftrated
by experi¬
ment.
684. E L E C T It
Principles oflong as tlie maclnne continues to charge the fecond bot-
Eiedtricily Ijigher, the cork balls will continue to repel each o-
ther ; but ceafe working the machine, and the cork balls
will ceafe to repel each other till they touch, and will
1 then very foon repel each other again } then let the ball
in the fir it phial approach the cork balls, and they will
now be attradled by it, inftead of being repelled as a-
bove, as in the laid experiment. This alfo plainly fhows,
that both fides of a Leyden phial are alike at the time
it is charging 5 and at the fame time evidently fhows,
that the difference of the two Tides does not take place
till after the bottle is charged, or till the machine ceafes
to charge it higher.
“ 3. In this experiment, let both of the former bot¬
tles be difcbarged, then let one of them be placed upon
the infulating Hand. Let a ball be put on over the fhar-
pened end of the third ware, and let it be laid on the
Hand as before, fo as to touch the coating of the phial :
place the other phial on the table, fo that its ball or
wire may touch the ball on the third wire, or any part
of the wire itfelf: make a communication from the ball
on the wire of the firlt phial to the prime condudtor :
then, by working the machine, both bottles will foon
become charged. As foon as they are pretty well char¬
ged, and before the machine ceafe working, remove the
fecond phial from the third wire •, after the fecond
phial is removed, ceafe wrorking the machine as foon
as poffible ", take the third ware, writh its two balls, off
the Hand with the hand, and lay it on the table, fo that
one of its balls may touch the outlide coating of the fe¬
cond phial : remove the firfl phial off the Hand, and
place it on the table fo as to touch the ball at the
other end of the third ware j then wath an infulated dif-
charging rod, make a communication from the ball in
one bottle to the ball in the other. If the outfide of the
firff phial be negative at the time it is charging, the in-
fide of the fecond will be the fame, and making the a-
bove communication would produce an explofion, and
both bottles would be difcharged j but the contrary
will happen, for there wall be no explofion, nor will ei¬
ther of the bottles be difcharged, although there be a
complete communication between their outfides, becaufe
the inffde of them both will be pofitive. This is a proof,
that confidering one fide of a phial to be pofitive and
the other negative at the time they are charging is a
miitake ; as well as that, if any number of bottles be
fufpended at the tail of each other, all the intermediate
furfaces or fides do not continue fo.
“ 4. Here alfo let the apparatus be difpofed as in the
laft experiment^ till the bottles are highly charged,
then with a clean flick of glafs, or the like, remove the
communication between the balls of the firfl; phial and
the prime condudlor, before the machine ceafes working:
then, with an infulated difcharging rod, make a com¬
munication from the outfide to the infide of the firfl;
phial j a ftrong explofion will take place on account of
the excefs withinfide, notwithftanding they are both
pofitive.
“ 5. This experiment being fomething of a continua¬
tion of the preceding one, immediately after the lart ex¬
plofion takes place, difcharge the prime condudlor of its
eledlricity and atmofphere ; then touch the ball in the
firft phial with the hand, or any conducing fubftance
that is pot infulated 3 then will the infide coating of the
I C I T Y.
Fart III.
firfl; phial, whLh at firfl was fo ffrongly pofitive, be in Principles erf
the fame Hate as the outfide coating of the fecond, hav-
ing a communication with the hand, the floor, &c. with eXperj_
each other 3 that is negative, if any thing can properly ment.
be called negative or pofitive that has a communication c—j
with the common flock : but a pair of cork-balls that
are eleiffrified either fi/i/s or minus will no more be at-
trafled by either the infide coating of the firft phial or
the outfide coating of the fecond, than they will by the
table on which they ftand, or a common chair in the
room, wLile they continue in that fituation. Remove
the aforefaid communication from the ball of the firft
phial 3 touch the ball in the fecond, as before in the
firft, or difcharge the bottle with the difcharging rod,
and the ball in the firft bottle will immediately become
negative ; with a pair of cork balls electrified negative¬
ly, approach the ball in the firft phial, and they will all
repel each other, or if the cork-balls be eleCtrified pofi-
tively, they will be attra&ed. All thefe circumftances
together ferve fully to prove what has already been faid,
not only that the infide of the firft phial, which was fo
ftrongly pofitive, may be altered fo as to become in the
fame ftate as the outfide of the fecond, without dif¬
charging the phial, or any more working the machine 3
but that it may be fairly changed, from being pofitively
charged to being negatively charged. If a pair of cork-
balls are now hung on to the ball of the wire in this
phial, by the help of a ftick of glafs, they will repel each
other, being negatively eleftrified. Make a communi¬
cation from the outfide of the bottle to the table, and
replace the communication from the prime conductor to
the ball in the bottle 3 thep, upon moderately working
the machine to charge the bottle, the cork-balls wall
ceafe to repel each other till they touch, and will foon * Brooles
repel each other again by being eleCtrified pofitively.
Here the working the machine anew, plainly fliows that
the infide of the firft bottle, wdiich was pofitive, waschap.^.
likewife changed to negative ^
The following obfervations and experiments on the Milner’s
Leyden phial, are taken from a little work by Hr iho-obferva-
T\/r*i tions and
mas Milner. _ x •_
An eleCtric power communicated to any infulated on
conduding fubftance has been named fimple eleCtrifica- the Leyden
tion, in order to diftinguifti this particular ftate from phial,
that of the charged phial : but it will appear whether
this diftindion ought to be retained or not, by taking
a comparative view of both thefe cafes. And, if the
changes which an eledrical power in general is capable
of making in the eledrical ftate of any fubftance con¬
tained within the fphere of its influence, be taken into
conlideration, and compared with thofe which have
been obferved in the charged phial, it is apprehended
that they will not appear to be different in any material
circumftance.
I. In the charged phial, when the infide has either
kind of eledricity communicated to it, the outfide is
found to poffels a contrary powyer. It appears alfo that
either kind of eledricity always produces the other on
any conduding fubftance placed within the fphere of
influence. And as the fame effed is alfo produced on
eledncs themfelves, in the fame fituation, and as lome
portion of the air, fuppofing no otner fubftance to be
near enough, muft be unavoidably expofed to fuch in¬
fluence, it neceffarily follows, that neither power can
exift
142
Chap. V. ELECT
prindplesof exift without the other $ and, therefore, in every pofli-
lEledlncity ljte cafe, pofitive and negative eleftricity are infeparably
illaftrated un;ted>
byment.n' IL A Plllal cannot be fulh charged m ^ wa7 hY
■ v i which the outiide acquires a contrary electricity, unleis
the external coating has a communication by iome con-
* duCtor with the earth. In the fame manner a full charge
of the contrary eleCtricity cannot readily be procured
without a limilar communication.
III. In both cafes the interpofrtion of an eleftric bo-
dy between the contrary powers is abfolutely necef-
fary. In one cafe that body is glafs, in the other it is
air j and the experiment will not lucceed in either, un-
lefs both the glafs and the air be tolerably free from
moifture.
IV. It appears that the influence of cleftricity acts in
the fame manner through glafs as it does through the
air, and produces a contrary power in both cafes.
V. A communication of the eleftric power is more
eaftly made through the fluid yielding fubftance ot the
air than through glafs, which is fo hard and iolid a bo¬
dy, as to require a very confiderable degree of power to
feparate its component particles : this however, fome-
times happens, and a hole is made through the glafs
itfelf, without deflgn, in attempting to charge a very thin
phial as high as poflible, in the moll favourable ilate of
the atmofphere.
VI. A conducing body receives the ftrongefl: charge
of the contrary eledlricity, when it is brought as near
as poflible to the eleftric power, without being in the
communicating diftance. And it is well known that the
thinneft phial, if it be ftrong enough to prevent a com¬
munication between the twro furfaces, will always receive
the higheft charge.
VII. The eleftricity of the external furface of the
charged phial cannot be deftroyed, fo long as the inter¬
nal furface remains in force, and continues to exert its
influence through the glafs j becaufe this influence was
the caufe of the contrary electricity on the external fur¬
face, and muft therefore preferve it.
VIII. If part of the courfe which the eledtric powder
takes in difcharging a phial be through the air, a fmall
part of the charge will always remain ; becaufe the whole
of the redundancy on one furface is not capable of for¬
cing a paifage through the refilling medium of the air,
in order to fupply the deficiency on the other furface.
But if every part of the circuit, from the internal to the
external coating, confilts of the belt conductors, and if
the coated furfaces be nearly equal, and diredtly oppo-
fite to each other, the phial will then appear to have re¬
tained no part of the charge } fo far as it is covered with
tin-foil •, but the parts of it above the coating on both
fides will, however, Itill retain the contrary eledtricities,
after the circuit has been completed. A relidue ot the
charge may alfo be obferved in every other inltance of
electrification, in which the degree of eledtricity is
futficient to force a communication between the elec¬
trified body and a condudtor not infulated, through a
fmall portion of the air : and if the experiment be
carefully made, it will appear, that the whole of the
redundancy is not capable of palling through the re¬
filling intermediate air, in any cafe, and therefore a
part of the charge mult always remain. But here it
will be proper to examine more particularly the nature
of the charged glafs..
r I C l T Y._ 685
Wiicn a plate of coated glafs lias been charged, and p' jn"plc.'°'
the circuit between the coatings has been completed, jd^rra^e(j
by the mediation of a good condudting fubltance, no ^ experi-
part of the coated furface is fuppofed to retain any part ment.
of the charge ; but, according to the commonly receiv- —v '
ed dodtrine, the wdiole of it is faid to be dilcharged j or
in other words, to be brought into its natural Hate.
This however is not really the cafe, as will evidently
appear from the following experiment j the delign of
which is to Ihow the effedts produced by charging and
difcharging a plate of glafs.
Let the middle of a piece of crown window glafs, fe-
ven inches fquare, be placed between two circular plates
of brafs, about the 16th part of an inch thick, and five
inches in diameter. In order to enable thefe plates to
retain a greater degree of power, it wall be proper to
terminate each of them with a round bead the third part
of an inch thick •, and the whole of the bead ftrould
be formed on one fide of the plate, that the other fide
may remain quite flat, and apply well to the furface of
the glafs. Let the whole be infulated about four inches
above the table, and in a horizontal polition, by faften-
ing one end of a cylindrical piece of fome good infula-
ting liibitance to the middle of the under plate, the o-
ther end of it being fixed in any convenient Hand. Let
a like infulating Item be fattened to the middle of the up¬
per plate. Let a brafs chain, which may eafily be re¬
moved, reach from the under plate to the table. In the ^
lalt place bend a piece ot brals wire into fuch a fliape,
that it may Hand perpendicularly on the upper plate ;
and let the upper extremity of this wire be formed into
a book, that it may be removed at any time by the aflift-
ance of a filk firing, without deftroying the infulation of
the plate-
The glafs being thus coated with metal on both fides,
and having alfo a proper communication wdth the table,
will admit of being charged } and both coatings may
be feparated from the glafs, and examined apart, with¬
out defiroying the infulation of either : for the upper
coating may be feparated by the means of its own pro¬
per Item ; and the under coating may be feparated by
taking hold of the corners of the glafs, and lifting the
glafs itfelf.. As glafs readily attracts moifture from the
atmofphere, it will therefore be neceffary to w>arm it in
the beginning, and to repeat it feveral times in the
courfe of the experiment, unlefs the air Ihould be very
dry.
Excite a fmooth glafs tube, of the common fize, by M4
rubbing it with filk, and apply it repeatedly to the bent
wire, until the glafs be w'ell charged. Then remove the
chain, which readies from the lower plate to the table,
and alfo the charging ware from the upper plate, by lay¬
ing hold of its hook with a filk firing. It necelfarily
follows, from confidering the quality of the power em¬
ployed in the prefent cafe, that the upper furface of the
glafs, together with the upper coating, muft be electri¬
fied poiitively ; and that the under furface and coating
muft be edeCtrified negatively } bu. as it is defigned in
this experiment to examine the powers of charged glafs,
that no virtue may be imputed to the glais but wdrat
really belongs to it, let both coatings be feparated from
it j and after they have been brought to their natural
ftate, by touching them with a conducting body not in¬
fulated, let the glafs be replaced between them j and
whatever effeCts may be now produced mult be alcnbed
M5
686 E L EOT
E!earicitvf-r°Iely t0 tlie p0’WerS °£ the c^rged glafs. On bring-
ilfuftrated ,a near t1ne uPper coating, a finall eleftrical
by experi- appear between that coating and the finger,
ment. attended with a fnapping noife. Apply a finger in the,
- lPle mamjer to the under coating, and the fame thing
mil nappen. Phis eft'eft Cannot be produced twice,
by two fucceeding applications to the fame coating ;
but it may be repeated feveral hundred times over,
in a favourable date of the atmofphere, by alternate ap¬
plications to the two coatings ; and the powers of the
glafs will be thus gradually weakened.
i his part of the experiment may be explained, by
obferving that the contrary eledlricities have a natural
tendency to produce and to preferve each other, on the
oppofite fides of a plate of glafs j and therefore, the in-
creafe or decreafe of power, on the other fide : and as
in charging a plate of glafs pofitively, no gradual addi¬
tion of eleftric matter can be made to the upper furface,
without a proper conveyance for a proportionable part
to pafs away from the lower furface j fo in this method
of uncharging it, the eledtric power cannot be gradually
taken away from the upper furface, without adding a
proportionable part to the under furface : one operation
is the reverfe of the other, and fo are the effe&s ; one
cafe being attended with an increafe and the other with
a decreafe of power.
Let the glafs be again fully charged, and after bring¬
ing both coatings to their natural ftate, as before, let
the glafs be replaced between them ; and on touching
the upper coating with a finger, and then feparating it
from the upper and pofitive furface of the glafs by the
infulating ftem, this coating will acquire a weak nega¬
tive power, which will be fufficient to produce a finall
fpark w’hile the glafs is in full force, though after the
powder of the glafs has been reduced, it will give little
or no fpark ; but in both cafes, on touching the coat¬
ings alternately two or three times, the negative power
of this coating, when feparated from the pofitive furface
of the glafs, will be fo confiderably increafed, as to pro¬
duce ftrong negative fparks.—This effect may now be
repeated feveral times, by only touching the upper coat-
Jng, but the fparks wall grow weaker every time ; and
tney may be reftored again to nearly their former
flrength, by alternate applications to both coatings, as
before. The fame things will alfo happen to the under
coating, in the fame circumftances 5 but wnth this differ¬
ence, that the power of the under coating, on being
feparated from the under and negative furface of the
glafs will be pofitive. And thus "a long fiicceflion of
both pofitive and negative fparks may be produced in
favourable weather, or at any time by" keeping the glafs
moderately warm.
It appears from this part of the experiment, that each
of the furfaces of the charged glafs has a power of pro¬
ducing a contrary eleftricity in the coating in contact
witn it, by a momentary interruption of the inhalation.
It neceffarily follows, in producing thefe effeds, th^t
more elefirical matter muff have paffed away from the
upper coating, at the time of touching it, than the fame
coating could receive from the upper furface of the glafs;
and therefore the upper coating, by lofing forne of its
natural quantity, will be negatively electrified ; and alfo
that more eledric matter mult have been added to the
under coating at the time of touching it, than the under
furface of the glafs could receive from it ; and therefore
4
11 I C I T Y. Part HI.
the under coating, by receiving fome addition toils na-Principles of
tuial quantity, will be pofitively eledrified. It appears Pledtricity
further, that the greateft degree of this inlluential power ilIuItratetl
which may be confiftent with the circumftances of the*
cafe, will be produced in either coating by taking care ^ m‘‘ ~ >
at the fame time to bring the oppofite coating into a
like ftate. of influential eledricity f and thus it is evident,
that the influential powers of the two coatings have the*
fame relation to each other, as the contrary powers of the
glafs itfelf, and will therefore always increafe or decreafe
together*
The glafs being again well charged, as at firft, let a I4g
brals wire bent in the form of a ftaple be brought in¬
to contad with the upper and lower coating at the
lame time. By this the common difeharge will be
made ; but the equilibrium of the coated glafs will be
only reftored in part; for a confiderable degree of at-
tradion will happen at the fame time between the up¬
per coating and the gials, which has frequently been
ftrong enough to lift a piece of plate glafs weighing
ten ounces. Neither coating wall now ihow the leaft
external fign of eledricity while it is in contad with
the. glafs: but on feparating either of them from
it, if care be taken to preferve their infulations, the
upper coating will be ftrongly eledrified negatively,
and the under coating will be ftrongly eledrified pofi-
lively. Let then both coatings be brought to their
natural ftate., by touching them when feparated from
the glafs, with a conducting body not infulated, and
let the glafs be replaced between them as before. In
this ftate of things, on touching the upper coating only,
and feparating it from the glafs, it wall not be capable’
of giving any fpark 5 but on touching the coatings alter¬
nately five or fix times, it wall then give a weak fpark ;
and this may now be repeated feveral times by only
touching the upper coating : but on a fecond applica¬
tion of the bent ware to both coatings at the fame time,
a fecond difeharge may be perceived, though much
weaker than the firft, and the coatings will be again
brought into the fame eledrical ftate as immediately
alter the firft difeharge. This may frequently be re¬
peated ; and a confiderable number of ftrong negative
fparks may be taken from the coating when it is fe¬
parated from the pofitive furface of the glafs. If the
glafs in replacing it between the two plates be turned
upfide down, the eledrical powrers of both coatings
will be changed by the next application of the dif-
charging ware to complete the circuit j and a fucceflion
of ftrong pofitive fparks may be taken from the coat¬
ing when it is feparated from the negative furface of
the glafs.
It appears from this part of the experiment, that
the coated part of the charged glafs was not brought
into its natural ftate by completing the circuit be¬
tween the coatings, but that it ftill "retained a degree
of permanent eledricity 5 that the powers of both
coatings were adually changed at the time of the firft
difeharge 5 and that a fucceftion of the fame pow'ers
may be produced in the coatings, without renewing
the leaft application of eledricity to the glafs itfelf.
The w'hole quantity of eledric power added to the 147
glafs in charging it, is evidently diftinguilhed into two
parts in this experiment. The firft part, which is by
far the moft confiderable, appears to have been readily
communicated from one furface of the glafs to the
other
Chap. V.
ELECT
Principles ofother, along the bent wire, when it was firft brought
tlluitrated ^nt° conta^ h°th coatings at the fame time». 'I'he
by experi- feconci Part °f the charge appears to be more perma-
"ment. nent, and remains ftill tmited with the glafs, notwith-
Handing the circuit has been completed (r). This
permanent electricity, as well as the other, muft be po-
fitive on the upper furface, and negative on the lower
furface : becaufe, in the prefent experiment, the charge
was given by a fmooth glafs tube excited with a filk
rubber. Now, the influence of the oppofite and per¬
manent powers on the different fldes of the glafs (each
iide having a tendency to bring the coating in con-
tad with it into a ffate of eleCtricity contrary to its
own) mult affiit each other, in caufing part of the elec¬
tric matter naturally belonging to the upper coating to
pafs away from it to the under coating, along the dif-
charging wire, and at the fame time the furcharge to
pafs the fame way. The upper coating, therefore, by
lofmg fome part of its natural quantity, muff be nega-.
lively electrified j and the under coating, by receiving
an addition to its natural quantity, muff be pofitively
eleCtrified. The whole quantity of eleCtric matter,
which the influence of the permanent eleCtricity of
the glafs is capable of taking from one coating and
of adding to the other, bears but a fmall proportion
to the whole charge : and therefore the fecond and
every fabfequent difeharge muft be conliderably weaker
than the firft. >
It appears from feveral of the preceding experi¬
ments, that a confiderable degree of influential power
may be produced at fome diltance by an eleCtric in full
force and therefore a fmall excited body of a cylin¬
drical ihape was fulficient to anfwer that purpofe : but
when the excited eleCtric has been fo far weakened
that it cannot communicate its own power, nor pro¬
duce this influential pow'er in any bodv, unlefs it be
brought very near or in contaCt with it, bodies of a
cylindrical form muft then aCt to great difad vantage,
and a fmall degree of power only can be produced j
becaufe the ftrength of the influential eleCtricity in this
cafe will be in proportion to the furfaces of the eleCtric
and conducting bodies, which are brought near toge¬
ther, or in contaCt with each other 5 and therefore a
plate of glafs in the fame circumftances, whether its
permanent powrer be derived from excitation or com¬
munication, is enabled from its Ihape to produce a con-
fiderable degree of the influential powers in the coat¬
ings in contaCt wflth it.
It has been very properly recommended to ufe
a particular kind of rubber, and to attend to the ftate
of it, in order to excite glafs well j but it will not be
necellary to pay the leaft regard to thefe circumftances
in the following experiments, in wdiich a method will
be fhown of charging a fmall phial and a plate of
glafs at the fame time, by a gradual accumulation of
power j that power being entirely derived from the
glafs itfelf, and with no other degree or kind of fric-
148
How to
charge a
phial with¬
out iric-
tion.
R I C I T Y. 687
tion than is neceffarily conneCled with the form of the l^inciplescff
experiment. qi^ftrateri”
Place a circle of tin-foil five inches in diameter on ^ CXper;,
the table, between a foil piece of baize and the middle meat,
of the fame plate of glafs that was ufed in the laft expe- u..—— .>
riment, which wall thus be coated on the under fide :
and in order to preferve a proper communication with
this coating, let a fillet of tin-foil reach from it beyond
the extremity of the glafs. The fame infulated metal
cover is to be ufed for the upper coating as before.
Let a thin ounce phial of glafs be filled with bra!3
filings, and coated with tin-foil on the outfide to a-
bout one inch from the top. Let a large brafs wire,
the fifth part of an inch in diameter, pafs through the
cork of the phial into the filings, about an inch of it
being left above the cork, and let the upper extremity
of this wire be wrell rounded. This experiment re¬
quires, that the whole conftrudtion fhould be well
warmed at firft 5 and it wall be neceffary to repeat it
at proper intervals, unlefs the atmofphere fliould be
very dry.
Taking bold of the wire of the phial with one
hand, let it be placed on the upper furface of the glafs,
and its bottom carried in contact over the middle of the
upper furface, as far as the tin-foil coating reaches on
the under fide : and during this part of the operation,
a finger of the other hand muft be kept in contabl with
the fillet of tin-foil. Then lifting the phial by the
wire with one hand, let it be placed on the infulated
metal cover, fufpended in the air with the other hand j
and after fluffing the hand from the wire to the coating,
let the bottom of the phial be placed on the end of the*
tin-foil fillet. Place the infulated metal cover on the
middle of the glafs, and touch it wflth a finger of one
hand, while the other hand touches the tin-foil fillet.
Now lift the infulated cover by its item, and bring the
head of the cover in contaft with the wire of the phial,
and a very fmall fpark of light will appear between them.
Let this be repeated in the fame manner about 15 times,
taking care to preferve a proper communication between
the coating and the floor. Then taking hold of the
phial by the coating, let it be replaced on the infulated
cover while it is fufpended in the air ; and after fluff¬
ing the hand from the coating to the wire, let it be
again placed on the middle of the glafs : and let the
bottom be again carried in contaeft over the middle of
the glafs, holding the wire in one hand, while the other
has a proper communication with the tin-foil coating.
Let the phial be again returned to the tin-foil fillet as
before, and let the inlulated cover be applied repeatedly
to the wire, immediately after every feparation from
the glafs j and a brighter fpark, together with a weak
fnapping, will now attend each application, if it be
carefully obferved to touch the cover with one hand
before every feparation, while the other hand refts on
the fillet of tin-foil. By proceeding in this manner,
after the third application of the phial to the glafs, a
very
a '^rS?me nCW t?r-mS ?em t0 be Wanted m °rder to exPrcfs with precifion the different parts of the charge
And ft that part of it which cannot be deftroyed by completing the circuit, fliould be called the permanent part
efthe charge, or more Amply the charge; then might the other part, or that which may be deftroyed by com-
pleting the circuit, be named the furcharge. J J LOili
688 ELECTRICITY. Part III
Principles of very weak fhock will be felt in tbofe fingers which are
Eledlnci y ufej [n completing the circuit of the glals •, and after
b iWptri- rePeat^r“g two rounds more in the manner before men-
tioned, t'ne phial will be fully charged* By applying
fc—y ' the coating of the phial when it is in full force to the
upper furface as before, the glafs plate will get the
greateft power it is thus capable of receiving, and will
then give a Ihock as high as the elbows. After this,
on attempting to lift the iniulated cover, the glafs it-
felf will generally be lifted at the fame time, with the
tin-foil coating adhering to the under furface : but by
continuing the reparations of the cover from the ^lafs,
a fucceilion of lirong negative fparks may be produced
by the influence of the upper furface •, and by turning
the glafs over, and leaving the tin-foil coating on the
baize, a fuccetiion of llrong politive fparks may be pro¬
duced by the influence of the other lide.
This experiment may be performed more fteadily
by placing the glafs, together with the tin-foil coat¬
ing and baize, on a plate of metal about one-tenth of
an inch thick, and of the fame fquare as the glafs. The
whole may be fattened together by two fmall hoidfatts
placed at the oppottte corners, which wTill prevent the
glafs from being lifted. This plate of metal will be
ufeful in another view 5 for after it has been futticiently
warmed, by retaining heat well, it will help to keep the
glafs dry, and confequently fit for ufe fo much the
longer. But when it fhall be required to fhow the con¬
trary powers of the oppofite fides of the glafs, it will
be more convenient not to fatten the parts together,
and the whole may be kept futficiently fteady, by the
operator’s keeping down one corner of the glafs with
a finger, and by placing a proper weight on the oppo¬
fite corner.
The bottom of the phial cannot be carried in con-
ta61 over the glafs without producing fome little de¬
gree of friftion ; from which the power in this experi¬
ment is originally derived* The cover will appear on
examination to be eleftrified negatively after every re¬
paration from the glafs : but as it was touched in com¬
pleting the circuit between the coatings before every
feparation, it neceffarily follows, that the cover can
have only an inttuential eledlricity, and confequently
that the permanent power of the upper furface of the
. glafs mutt be pofitive. The negative power of the co¬
ver is communicated to the wire of the phial, by which
the infide is eletlrified negatively and the outlide pofi-
tively •, and both thefe powers will increafe wfith every
application, becaufe the circumftances of the phial are
favourable to its charging. The phial mutt be infulat-
ed every time it is required to ttiift the hand from the
wire to the coating, or from the coating to the wire ‘7
for without this precaution the phial would be difehar-
ged. By applying the outflde of the phial to the up¬
per furface of the glafs, in the manner above mention¬
ed, the phial will be partly difeharged on the furface ;
and though it mutt be therefore weakened, the power
of the glafs will be increased, and confequently enabled
to produce a proportionably (tronger effe<tt on the brafs
cover, which by the next round of applications will
give the phial a ttronger charge than it had before. And
thus a very fmall degree of original power is firft gene¬
rated, and then employed in forming tw^o different ac¬
cumulations : and by making each of thefe fubfervient
to the increafe of the other, the phial is at laft fully
3
charged, and the glafs plate acquires fuch a degree of Pnndplesof
the furcharge, as to give a pretty fmart Thock j and Eleftndty
after, it remains capable, by the influence of its perma-
neat powers, of producing a fuccettion of pofitive and
negative fparks on the oppofite furfaces*   , « 1
The contrary charge may be given to the phial
by taking hold of the coating, and carrying the wire
in contact over the middle of the upper furface of the
glafs, and by applying the power of the infulated co¬
ver to the coating ; for if the operation be conducted
in every other refpedt in the fame manner as before,
then will the iniide be electrified poutively, and the
outfide negatively. The powers of the glafs plate will
be the fame as they were in the former cafe*
Alter the phial has been fully charged negatively,-
by the procefs of the lalt experiment, let it be infu¬
lated j and taking hold of the wire, let the bottom be
held uppermott, and let the hand which holds it reft on
the fillet of tin-foil. Apply the infulated cover to the
glafs, and after touching it wdth a finger of the other
hand, fepaiate it from the glafs j and on bringing it to¬
wards the coating of the phial, a ftrong fpark will pals
between them. After repeating this between 20 and
30 times, the powers of the phial will be deftreyed $
and by continuing the fame operation, they will be in¬
vented 5 for the infide will be at laft fully charged po-
fit.vely, and the outlide negatively.
The fame effedt may be produced by turning the
glafs over, and by repeatedly applying the influen¬
tial eledlricity, produced on that lide, to the wire of
the phial.
w hen the phial has been fully charged negatively,
as in the laft experiment, take hold of the coating of
the phial wdth one hand, and while the other hand
relts on the tin foil fillet, apply the wire to the middle
of the upper furface of the glafs, as far as the tin-foil
coating extends on the other fide. By this the powers
of the glafs plate will be changed*
Another, and perhaps a better method of apply- 145
ing the phial, is to place the infulated cover on the
furface of the glafs, and then holding the phial by the
coating in one hand, to apply the wire to the cover,
while the other hand touches the fillet of tin-foil; by
which a ftiock will be given, and the fame charge of
powers will be produced in an inftarit, which before took
up fome little time. On lifting the infulated cover Ly its
ftem immediately after the fhock, it will be negative, or
have the fame power as the infide of the phial j but on
replacing the cover, and completing the circuit of the
glafs plate, the furcharge will be dettroyed ; another
ihock will be felt $ and the power of the cover, after the
next feparation, will be pofitive, or contrary to that of
the infide of the phial. Apply this pofitive power to
the wire of the phial as before-, and after 15 applica¬
tions, the powers of the phial will be dettroyed ; and
by ftill proceeding in the fame manner, the powers of
the phial will be changed, and the infide will be fully
charged pofitively, and the outfide negatively, by 60
applications.
Thefe effefts may alfo be produced by a fingle ap¬
plication of the coating of the phial to the other fide
of the glafs plate j and by repeated applications of the
influential eleftricity, produced on the fame fide, to the
coating of the phial.
If it were fimply the objett in this experiment to *^
change
Chap. VI.
ELECTRICITY.
Principles of change the powers of the phial, the operation might
then be confiderably Ihortened, by completing the cir-
byexpeti- cu^t t^le P^iah an<l confequently deftroying the whole
ment> furcharge : but it was intended to fhow what effects
■■v-. i might be produced, by oppoling the contrary powers
to each other ; and by doing this it appears that either
fide of the glafs plate can deltroy the powers of the
phial, and give it a contrary charge j that either fide
of the phial can alfo change the powers of the glafs
plate ; and that the powers of the glafs plate, thus in¬
verted, can again deftroy the powers of the phial, and
give it a full charge of the contrary eleftricity.
Here it may be obferved, that, in fome cafes, the
quality of the power may be determined by obfervation
alone. When the phial employed in the two laft expe¬
riments has been fully charged, it may be known whe¬
ther the infide be pofitive or negative from the light
which appears at the wire, or from the hilling noife
which attends it : for when the phial has been fully
charged pofitively, if the room be fufficiently dark¬
ened, a bright luminous appearance may be feen, di¬
verging in feparate rays to the diftance of an inch, at¬
tended with an interrupted luffing noife ; and both the
light and the noife continue a very lliort time. But
when the phial is fully charged negatively, a weaker
and more uniform light appears, which does not extend
itfelf more than the fixth part of an inch, and is at¬
tended with a clofer and more uniform hilling j and
this noife and light always continue longer than the
former. Even pofitive and negative fparks, palling be¬
tween the infulated cover and a finger, may be diffin-
guilhed from each other: for the pofitive fparks are
more divided, give lefs light, make a weaker fnapping
noife, and affedl the finger lefs fenfibly than the nega¬
tive. \
The ftrongeft fparks which can be produced in thefe
experiments, are thofe that pafs between the coating of
the phial and the infulated cover, when they poffefs the
contrary powers ; but they will be more particularly
vigorous if the coating be pofitive, and the infulated
cover negative *.
689
Chap. VI. Mifcellaneous Experiments ’with charged
Electrics.
* Milner,
Experi¬
ments and
Obferma-
tiont.
Cigna’s ex- SlG. Cigna made fome curious experiments on the
periments adhefion of eleftrified plates of glafs. He laid two of
on charged thefe plates well dried, one upon the other as one
F a es‘ piece, the lowermoft of them being coated on the out-
fide j and, when they were infulated, he alternately
rubbed the uppermolt plate with one hand, and took
a fpark from the coating of the lower with the other
till they were charged j when the coating and both
the plates adhered firmly together. Giving a coating
to the other fide, and making a communication between
the two coatings, the ufual explofion was produced.
But, though the united eledtric was thus difcharged,
the plate ftill cohered, and though no fign of eledlricity
appeared while they were united, they were, when fe-
parated, found pofleffed of oppofite ftates of eledlri-
city.
If the two plates were feparated before they were
tlifcharged, and the coating of each was touched, a
fpark came from each, and when they were again pla-
Voi*. VJL Part II.
ced together, they cohered as before, but were not ca-Principles of
pable of giving a Ihock f. Electricity
If plates of glafs, thus coated and electrified, be fe-
parated in the dark, flatties of light wall be perceived menu
between them. By laying the plates together again, v-—
and again feparating them fuccelfively, the appearance t °f
of thefe luminous flalhes may be repeated feveral times, Aca^' °E
but always in a weaker degree than the firft. , ur/n' or
Mr Symmer made feveral experiments of the fame 3
kind before Sig. Cigna. He found that when the two
plates were coated only on one fide, they were charged
as one plate, and the uncoated fides adhered together j
but when they were coated each on both fides, they
became charged diftin&ly from each other, and did not
adhere. iqt
Mr Henley, in defcribing an experiment of this kind,Mr Henly^
makes the following obfervation. “ Crown glafs, thatremarks*
is, the glafs commonly ufed for fafli-windows, though
fo much thinner, fucceeds in this experiment as well as
the plate-glafs ; but what is very remarkable, the
Dutch plates, when treated in the fame manner, have
each a pofitive and a negative furface, and the ele&ri-
city of both furfaces of both plates is exchanged for
the contrary electricity in the difcharge. If a clean,
dry, uncoated plate of looking-glafs be placed between
the coated looking-glafs plates, or between the plates
of crown-glafs, it appears after charging, to be nega¬
tively eleftrified oa both fides ; but if it be placed be¬
tween the Dutch plates it acquires, like them, a pofitive
eleCtricity on one furface, and a negative eleCtricity on
the other”. j..
A very curious and elegant experiment on the Ley-Curious ex-
den phial was made by Profeflbr Richman of Peters-P‘:ritnen1:.
burgh, whole unfortunate death will be hereafter re-^i^^|'or
lated.
He coated both fides of a pane of glafs, within twro
or three inches of the edge, and fattened linen threads
to the upper part of the coating, on both fides; which,
when the plate was not charged, hung down in contaCt
with the coating : but fetting the plate upright and
charging it, he obferved, that when neither of the fides
was touched by his finger, or any other conductor com¬
municating with the earth, both the threads were re¬
pelled from the coating, and flood at an equal diftance
from it •, but when he brought his finger or any other
conductor to one of the fides, the thread hanging to
that fide fell nearer to the coating, wEile the thread
on the oppofite fide receded as much ; and that when
his finger was brought into contaCl with one of the
fides, the thread on that fide fell into contaCf with it
likewife, while the thread on the oppofite fide receded
to twice the diftance at which it hung originally j fo
that the two threads always hung fo as to make the
fame angle with one another
One of the molt diverting experiments with charged MaSic P^c"
eleCtrics, is that which Dr Franklin calls the Magic^'
Pitfure, and which he defcribes in the following man¬
ner. Having a large mezzotinto print (fuppofe of the
kmg^, with a frame and glafs ; take out the print and
cut a pannel out of it, near two inches diftant from the
frame all round. If the cut be through the picture, it
is not the worfe. With thin pafte or gum-water,
the board that is cut off on the infide of the glafs, pref-
fing it fmooth and clofe, then fill up the vacancy by
4 S gilding
690
ELECTRICITY.
Part III„
Letters.
155 ,
Electrical
jack.
Principles of gilding the glafs well with gold or brafs leaf. Gild
inner edge of the back of the frame all
b ye x peri roun^» except the top part, and form a communication
ment. between that gilding and the gilding behind the glafs j
Y~ "-1 then put in the board and that fide is finilhed. Turn
up the glafs, and gild the forefide exaftly over the
back gilding 5 and when it is dry, cover it, by palling
on the pannel of the pidlure that has been cut out, ob-
ferving to bring the correfpondent parts of the board
and picture together, by which the picture will appear
, of a piece as at firft, only part is behind the glafs, and
part is before. Laftly, hold the picture horizontally
by the top, and place a little moveable gilt crown on
the king’s head.
If now the picture be moderately eledlrified, and
another perfon take hold of the frame with one hand,
fo that his fingers touch its infide gilding, and with the
other hand endeavour to take off the crown, he will
receive a fevere Ihock, and fail in the attempt. The
operator who, to prevent it from failing holds the pic¬
ture by the upper end, wrhere the infide of the frame is
not gilt, feels nothing of the Ihock, and may touch the
face of the pidlure with impunity, which he pretends to
* Franklins ^ a left of his loyalty. If a ring of perfons take a
Ihock among them, the experiment is called the con-
fpirators *.
On the fame principle that the wires of phials charg¬
ed differently, will attradl and repel differently, is
made an eleBrical wheel, which, Dr Franklin fays,
turns with confiderable ftrength, and of which he gives
the following defcription. A fmall upright lhaft of
wnod paffes at right angles through a thin round board,
of about twelve inches diameter, and turns on a lharp
point of iron, fixed in the lower end *, while a ftrong
wire in the upper end, pafiing through a fmall hole in
a thin brafs plate, keeps the fliaft truly vertical. About
thirty radii of equal length, made of fafh-glafs, cut in
narrow flips, iffue horizontally from the circumference
of the board j the ends moil difiant from the centre,
being about four inches apart. On the end of every
one a brafs thimble is fixed.
If now the wire of a bottle ele&rified in the common
way, be brought near the circumference of this wheel,
it will attract the neareft thimble, and fo put the wheel
in motion. That thimble, in palling by, receives a
fpark, and thereby being eleftrified is repelled, and fo
driven forwards j wdiile a fecond being "attradled, ap¬
proaches the wire, receives a fpark, and is driven after
the firft ; and fo on till the wheel has gone once round;
when the thimbles before electrified approaching the
wire, inftead of being attradled as they wrere at firft,
are repelled, and the motion prefently ceafes.
But if another bottle which had been charged through
the coating, be placed near the fame wheel, its wire
will attract the thimble repelled by the firft, and there¬
by double the force that carries the wheel round } and
not only taking out the eledlric power that had been
communicated by the thimbles to the firft bottle, but
even depriving them of their natural quantity, inftead
of being repelled when they come again towards the
firft bottle, they are more ftrongly attradled ; fo that
the wheel mends its pace, till it goes with great rapidi¬
ty, 12 or 15 rounds in a minute, and with fuch ftrength,
that the weight of 100 Spanifh, with which it was
once loaded, did not feem in the leaft to retard its mo¬
tion. This is called eleBrical jack, and if a large Principles of
fowl was fpitted on the upper ftiaft, it would be carried f kcftncity
round before a fire, with a motion fit for roafting. by'exuerf
But this wheel, like thofe driven by wind, moves
by a foreign force, viz. that communicated to it by the
bottles. ls6
The felf-moving wheel, though conftrudled on the Self-mov-
fame principles, appears more iurprifing. It is made ing wheel,
of a thin round plate of window glafs, feventeen inches
in diameter, well gilt on both fides, to within twro in¬
ches of the circumference. Two fmall hemifpheres of
wood are then fixed wuth cement, to the middle of the
upper and under fides, centrally oppofite, and in each
of them a thick ftrong wire, eight or ten inches long,
together making the axis of the wheel. It turns hori¬
zontally on a point at the lower end of its axis, which
refts on a bit of brafs cemented within a glafs fait fel¬
ler. The upper end of its axis paffes through a hole in
a thin brafs plate, cemented to a long and ftrong piece
of glafs j which keeps it fix or eight inches diftant from
any non-eledlric, and has a fmall ball of wax or metal
on its top.
In a circle on the table which fupports the wheel,
are fixed twelve fmall pillars of glafs, at about eleven
inches dillance, with a thimble on the top of each. On
the edge of the wTheel is a fmall leaden bullet, communi¬
cating by a wire wuth the upper furface of the wheel j
and about fix inches from it, is another bullet, com¬
municating, in like manner, with the under furface.
When the wdteel is to be charged by the upper furface,
a communication muft be made from the under furface
wuth the table.
When it is well charged it begins to move. The
bullet neareft to a pillar moves toward the thimble on
that pillar, and palling by, electrifies it, and then
pulhes itfelf from it. The fucceeding bullet, which
communicates with the other furface of the glafs, more
ftrongly attraCls that thimble, on account of its being
eleCirified before by the other bullet, and thus the
wheel increafes its motion, till the refiftance of the air
regulates it. It will go half an hour, and make one
minute with another, twenty turns in a minute, which
is fix hundred turns in the wdiole, the bullet of the up¬
per furface giving in each turn, twelve fparks to the
thimbles, which makes feven thoufand two hundred
fparks, and the bullet of the under furface receiving as
many from the thimble, thefe bullets moving in the
time near twro thoufand five hundred feet. The thim¬
bles are well fixed, and in fo exaCt a circle, that the
bullets may pafs within a very fmall diftance of each of
them.
If inftead of two bullets you put eight, four com¬
municating with the upper furface, and four with the
under furface, placed alternately, (which eight at about
fix inches diftance, complete the circumference) the
force and fwiftnefs will be greatly increafed, the wheel
making fifty turns in a minute, but then it will not
continue moving fo long.
Thefe wheels may be applied perhaps to the ringing Leturi
of chimes, and moving light made orreries *. 157
Mr Cavallo gives the following defcription of anSelf-charg-
inftrument wdfich he calls the felf charging Leydenxxf. Leyden
Phial. _ _ _ P
Take a glafs tube of about eighteen inches in length,
and an inch, or an inch and a half, in diameter. It is
immaterial
* Franklin s
Chap. VII. ELECT
Principles of immaterial whether one of its ends be clofed or not.
Eleftricity 0oat Qf wJth tin-foil, but only from one
jlluftrated ^ . r • i r . ,
by experi- °Pen extremity ox it about as tar as its middle ; the
ment. other part, which remains uncoated, wTe (hall call the
v-"-. i naked part of the inftrument. Put a cork into the aper¬
ture of the coated end, and let a knobbed wire pafs
through the cork, and come in contaft with the coat¬
ing. The inftrument being thus prepared, hold it in
one hand by the naked part, and with the other hand
clean and dry-rub the outfide of the coated part of the
tube ; but after every three or four ftrokes you muft re¬
move the rubbing hand, and muft touch the knob of
the wire, and in fo doing a little fpark will be drawn
from it. By this means the coated end of the tube will
gradually acquire a charge, which may be increafed to
a conftderable degree. If then you grafp the outfide
of the coated end of the tube with one hand, and touch
the knob of the wire with the other hand, you will ob¬
tain a fhock, &c.
In this experiment the coated part of the tube an-
fwers the double office of eleftrical machine and of
Leyden phial ; the naked part of it being only a fort
of handle to hold the inftrument by. The fridftion on
the outfide of the tube accumulates a quantity of pofi-
tive electricity upon it, and this eleftricity forces out
of the infide a quantity of electricity alfo pofitive.
Then by taking the fpark from the knob, this infide
electricity, wffiich is by the coating communicated to
the knob through the wire, is removed, confequently
the infide remains undercharged or negative, and of
courfe the pofitive eleCtricity of the outfide comes clof-
er to the furface of the glafs, and begins to form the
charge. By farther rubbing and taking the fpark from
the knob this charge is increafed, &c.
Inftead of a tube, this inftrument may be conftrufted
with a pane of glafs, in which cafe it will be rather
limpler, but it cannot be managed fo eafily, nor of
courfe can it be charged fo high as the tube. A piece
of tin-foil muft be palled in the middle of only one
lurface of the pane, leaving about two inches and a
half or three inches of uncoated glafs all round. This
done, hold the glafs by a corner, wfith the coated fide
from you, and with the other hand rub its uncoated
fide, and take the fpark from the tin-foil alternately,
until you think that the glafs may be fufficiently charg¬
ed ; then lay the glafs with its uncoated fide fiat upon
one hand, and on turning the tin-foil with the other
hand you will receive the ffiock.
Chap. VII. Of the chemical ejfefis of the EleFlric
Spark.
15* The electric fbarh fets fre to inflammable bodies.
To fire ro- Exper. 1.—To fire rofln. Wrap fome cotton wool,
fin- containing as much powdered rofin as it will hold, about
one of the knobs of a difcharging rod. Then having
charged a Leyden jar, apply the naked knob of the
rod to the external coating, and the knob enveloped
by the cotton to the ball of the wire. The aft of dif¬
charging the jar will fet fire to the rofin.
A piece of phofphorus or camphor wrapped in cot¬
ton wool, and ufed in the fame wray, will be much more
T ^ eafily inflamed.
To fire Exper. 2.—To fire fpints. Hang a fmall ball with
fpirits. a ftem to the prime conduftor, fo that the ball may
R I C I T Y. 691
projeft below the conduftor. Then w-arm a little ar-Principles of
dent fpirit, by holding; it a ftiort time over a candle in a Electricity
. r 1 , P , ^ , illuftrated
metallic fpoon \ hold the fpoon about an inch below ^ u^rat^.
the ball, and fet the machine in motion. A fpark will ment,
foon iffue from the ball and fet fire to the fpirits. 1
This experiment fucceeds in the very fame manner,
whether the conduftor is eleftrified pofitively or nega¬
tively, i. e. whether the fpark be made to come from
the conduftor or from the fpoon ; it being only in con-
fequence of the rapid motion of the fpark that the fpirits
are kindled.
It wall be perhaps fcarce neceffary to remark, that
the more inflammable the fpirits are, the more proper
they will be for this experiment, as a fmaller fpark will
be fufficient to inflame them ; therefore reftified fpirit
of wane is better than common proof fpirit, and aether
is better than either.
This experiment may be varied different ways, and
may be rendered very agreeable to a company of fpec-
tators. A perfon, for inftance, Handing upon an elec¬
tric ftool, and communicating with the prime conduc¬
tor, may hold the fpoon with the fpirits in his hand,
and another perfon, Handing upon the floor, may fet
the fpirits on fire, by bringing his finger within a fmall
diflance of it. Inflead of his finger, he may fire the
fpirits with a piece of ice \ when the experiment wrill
feem much more furprifing. If the fpoon is held by
the perfon Handing upon the floor, and the infulated
perfon brings fome condufting fubflance over the fur-
face of the fpirit, the experiment fucceeds as well.
Mr Winckler fays, that oil, pitch, and fealing-wax,
might be lighted by eleftric fparks, provided thofe
fubflances were firfl heated to a degree next to kind¬
ling. To thefe it mult be added, that Mr Gralath
fired the fmoke of a candle juH blown out, and light-
ed it again j and that Mr Boze fired gunpowxler, melt¬
ing it in a fpoon, and fired the vapour that role from
it *. * Pritjiley,
This experiment will fucceed better with a charged H^' Elea’
jar-
Exper. 3. To fire hydrogenous gas.—Provide a bot-To fire hy-
tle of firong glafs with two necks, as a, fig. 48. Let adrogenous
brafs cap be fitted to each neck r, d; one of which ^3Spi
is furnilhed with a cock, and through the other c, CLXXXIX
a glafs tube j- r is paffed, containing a ware projefting
beyond the tube at one end, which is terminated by a
knob /?, while the other paffing within the bottle turns
round fo as to come within an inch of the brafs through
which the glafs tube paffes. The bottle being thus
prepared, fill it with water, and throw up into it equal
parts of hydrogen gas and common air ,or three parts
of hydrogen and one of oxygen gas; fix in the cork,
and ffiake the bottle fo as to mix the gafes well toge¬
ther. Then bring the knob «, near the knob of a
charged jar, or a ball of the prime conduftor, and the
hydrogen will be inflamed with a loud report.
In general the cork will be forced out by the explo-
fion 5 but if this fhould not be the cafe, an opportunity
is afforded of proving that the gafes have difappeared,
and wrater has been produced by the experiment. On
taking out the cork below the furface of wTater, the
water wall rulh in, and fill the bottle, thus ffiewing that
the gafes have difappeared.
To prove the produftion of water, it is neceffary
that the bottle ihould have been filled with mercury
4 S 2 before
6g:
ELECT
Principles of before tbe gafes were introduced. In both cafes drops
■Eledricity of water will appear within the bottle after the report;
h^expen* ^ut whcre water has been employed in introducing the
ment. ga^es» tellimony is more equivocal than when no
( v— ' water has been ufed.
* Phil. The firft perfon who fired inflammable bodies by the
<Tranf. eledlric fpark, was Dr Ludolf of Berlin, in 1774, who,
vo!. x. ^ gy fparks excited by the fridlion of a glafs tube, kin-
f 1\ ollet s jjjgj ethereal fpirits of Frobenius *. Mr Gordon
of Erfurd, produced lb ftrong a fpark from the back
of a cat, as to fire fpirit of wane f.
Exper. 4.—It has been propofed by Sig. Volta to
Refsarches,
£. 98.
161
Inflamma¬
ble air
lamp.
R I C I T Y. Part HI.
gafes, and forms new compounds with their component Principles of
principles. Electricity
The firft who examined the adtion of electricity on hyexperf
the gafes, was Dr Prieftley. In the courfe of his ex- meat,
periments on air, he found that by means of the elec- —v——^
trie fpark, he could convert the blue colour of a vege- l63
table infufion into red. The inftrument ufed in this ex- ty1^!<jn(cj)f;c
periment, was a glafs tube about four or five inches fparjc on
long, and one or two tenths of an inch in diameter in the gafes.
the infide ; a piece of wire was put into one end of the 164
tube, and fixed there with cement j a brafs ball was fix- ExPerI-
ed on the top oi this wire ; the lower part of the tube
apply the bunting of hydrogen gas to economical pur- ^was filled with water, tinged blue with a piece of turn-iey#
merits of
Dr Pritft-
pofes, in what he called the infiammahle air lamp
A, fig. 49. is a glafs globe for containing the gas 5
B a glafs bafon or refervoir for holding water j D a
cock to form a communication between the wrater and
the gas. The water pafies into the globe through the
metal pipe^, which is fixed to the upper part of the
refervoir A j at r is a cock to cut oft or open a com-
muhfeation between the air and the jar K. N is a
fmall pipe to hold a piece of wax taper j L a brafs
pillar, on the top of which is a ball of the fame metal;
a, is a pillar of glafs with a focket at the top, in which
Aides the wire b, having a ball ferewed on the end of
it. F, is a cock by which the globe is filled wdth hy¬
drogen gas, and which afterwards ferves to confine the
gas and what water falls from B into A.
To ufe this inftrument, having filled the globe with
gas, and the refervoir A with wTater, turn the cocks D
and r, and w^ater wdll fall into the globe, forcing up a
quantity of gas, which wall rife through the pipe K.
If now an eleftric fpark be made to pafs from the ball
m to that marked n, it will fet fire to the inflammable
gas which pafles through the pipe K. To extinguifh
the lamp, firft fhut the cock r, and then D.
The gas is obtained in the ufual way from diluted
fulphuric acid and iron filings, and the globe is to be
filled in the following manner. Having previouily fil¬
led it wflth water, place the foot A in a tub of wTater
fo that it may be covered, and that the bent glafs tube
through which the gas is to be introduced, may pafs
commodioufly below the foot. When the gas has dri¬
ven out nearly all the water, turn the cock F, and the
162 lamp is ready for ufe.
To fire gun- Exper. 5. To fire gunpowder.—Fix a fmall cartridge
powder. on a metallic ware which is fitted to a glafs or wooden
handle j make a communication between the wire and
the ground 5 then prefent the cartridge to the knob of
a charged Leyden phial, and the gunpowder will be
fired.
Fig. 50. reprefents a fmall cannon, with an ivory touch-
hole fitted with a brafs pin furnifhed with a round head.
Gunpowder may be fired from this cannon by the elec¬
tric fhock, in the following manner. Charge the can¬
non with gunpowder as ufual \ then fill the touch-hole
with powder, ram it well down, and pufh into it the
brafs pin fo that its end may be near the bottom of the
hole. Now make a communication between the outfide
of a large charged jar, or a battery, and the body of the
cannon; then, placing one ball of a difeharging rod
on the head of the pin, which pafles down the touch-
hole of the cannon, and bring the other to the knob of
the jar, and the difeharge will fire the cannon.
The eleBric fparh decompofes mofi of the compound
foie or archil. This was eafily eftedted by fetting the
tube in a veflel of the tinged w-ater, then placing it un¬
der a receiver on the plate of an air-pump •, exhaufting
the receiver in part, and then, on letting in the air,
the tinged liquor rofe in the tube, and the elevation
would be in proportion to the accuracy of the vacuum j
now taking the tube and veflel from under the re¬
ceiver, he threw ftrong fparks on the brafs ball from
the prime conductor.
When Dr Prieftley made this experiment, he per¬
ceived, that after the eledhric fparks had been palled
between the ware and the liquor for about a minute,
the upper part of the liquor began to look red \ in two
minutes it was manifeftly fo, and the red part did not
readily mix wflth the reft of the liquor. If the tube
wras inclined where the fparks were palled through it,
the rednefs extended twice as far on the lower fide as
on the upper. In proportion as the liquor became red,
it advanced nearer to the wire, fo that the air through
which the fparks were pafled, was diminilhed j the di¬
minution amounted to about one fifth of the wfliole fpace $
after which a continuation of the eleftric fparks pro¬
duced no fenfible effeft.
To determine the caufe of the change of colour, Dr
Prieftley expanded the air in the tube by means of an
air-pump, till it expelled all the liquor, and admitted
frefh blue colour in its place j but after this, eleftricity
produced no fenfible effeft on the air or on the liquor;
fo that it w^as clear, that the air had been decompofed,
and fomething of an acid nature had been produced.
The refuit was the fame wflth wires of different metals.
It wras alfo the fame, when by means of a bent tube,
the fparks wore made to pafs from the liquor in one leg
of the tube to the liquor in the other. The air thus
diminifhed, wras in the higheft degree noxious.
In paflmg the eleftric fpark through dirferent gafes,
it appears of different colours. In carbonic acid gas,
the fpark is very white } in hydrogenous gas, and am-
moniacal gas, it appears of a purple or red colour.
Dr Prieftley found that the eleftric fpark pafled
through any kind of oil, produced an inflammable gas.
He tried it wflth oil of olives, oil of turpentine, and ef-
fential oil of mint. The eleftric fpark when pafled
through ether, produces the fame effeft.
’ He found that the eleftric fpark when pafled through
ammoniacal gas, increafes the bulk of this gas j fo
that, by making about two hundred fhocks pafs through
a given quantity of it, the original quantity was fome-
times increafed one fourth. If water was admitted
to this gas, it abforbed the original quantity, and left
about as much gas as was generated by the eleftricity,
and this was a ftrongly inflammable gas.
Dr
Chap. VII. E L E C T
Principles of Dr Frieflley found, that on paffing flight electric
Electricity {]loc^s for about an hour, through an inch of carbonic
illufti ated acidgas, confined in a glafs tube one-tenth of an inch in
"ment. diameter, when water was admitted to it, only one fourth
^ - ■' ' of the air was abforbed.
He likewife found, when the electric fpark was paf-
fed through carbonated hydrogen gas, that the inlide of
the tube in which the gas was confined, was covered
with a blackifh fubftance.
Dr Prieitley took the frmple eleftric fpark from a
conductor of a moderate fize, for the fpace of five mi¬
nutes without interruption, in a quantity of carbonated
hydrogen gtts, without producing any change in the in-
fide of the glafs} when immediately after, paffing
through it only two fhocks of a common jar, each of
which might be produced in lefs than a quarter of a
minute with the fame machine in the fame date, the
whole of the infide of the tube was completely covered
with the black matter.
A large phial, about an inch and a half wide, being
filled with this gas, the explofrons of a very large jar,
containing more than two feet of coated furface, had no
effedf upon it} from which it feems, that in thefe cafes
the force of the fhock was not able to decompofe the
gas.
Several valuable experiments were made by the
Hon. Henry Cavendith, of which he gave an account
in the '73 d volume of the Phil. Tranf.
The apparatus ufed in making the experiments was
Mr Caven- as follows. The air, through which the fpark was in-
dlfli’s expe- tended to be paffed, wTas confined in a glafs tube M,
riments. to an angle, as in fig. 51. which, after being fil¬
led with quickiilver, wTas inverted into two glalles of
the fame fluid, as in the figure. The air to be tried,
was then introduced by means of a fmall tube, fuch as
is ufed for thermometers, bent in the manner reprefent-
ed by ABC, fig. 52. the bent end of which, after be¬
ing previoufly filled with quickfilver, was introduced,
as in the figure, under the glafs DEF, inverted into
water, and filled with the proper kind of air, the end
C of the tube being kept flopped by the finger •, then,
on removing the finger from C, the quickfilver in the
tube defcended in the leg BC, and its place was fup-
plied with air from the glafs DEF. Having thus got
the proper quantity of air into the tube ABC, it was
held with the end C uppermofl, and flopped with the
finger} and the end A, made fmaller for that purpole,
being introduced into one end of the bent tube M,
fig. 51. the air, on removing the finger from C, was
forced into that tube by the preffure of the quickfilver
in the leg BC. By thefe means he was enabled to in¬
troduce the exacl quantity of foap-lees, or any other
liquor which he wanted to be in contact with the air.
In one cafe, however, in which he wanted to intro¬
duce air into the tube many times in the fame experh
ment, he ufed the apparatus reprefented in fig. 53. con-
filling of a tube AB of a final] bore, a ball C, and a
tube DE of a larger bore. This apparatus was firll
filled with quickfilver, and then the ball C and the
tube AB were filled with air, by introducing the end
A under a glafs inverted into water, which contained
the proper kind of air, and drawing out the quickfilver
from the leg ED by a fiphon. After being thus fur-
nifhed with air, the apparatus was weighed, and the
end A introduced into one end of the tube M, and
r 1 c 1 T Y. 693
kept there during the experiment J the way of forcingthincipleso
air out of this apparatus into the tube, being by thrufl- ;]juftrateci
ing down the tube ED a wooden cylinder, of fuch a ^ experi-
fize as almofl to fill up the whole bore, and by occa- ment.
fionally pouring quickfilver into the fame tube, to fup- v
ply the place of that puihed into the ball C. After
the experiment was finifhed, the apparatus was weighed
again, which fhewTed exadlly how much air had been
forced into the tube M, during the whole experiment j
it being equal in bulk to a quantity of quickfilver,
whofe weight wras equal to the increafe of weight of the
apparatus.
The bore of the tube M ufed in moll of the follow¬
ing experiments, was about one-tenth of an inch , and
the length of the column of air, occupying the upper
part of the tube, was in general from one and a half
to three-quarters of an inch.
In order to force an eledlrical fpark through the
tube, it was neceffary, not to make a communication
between the tube and the conductor, but to place an
infulated ball at fuch a dillance from the conductor, as
to receive a fpark from it, and to make a communica¬
tion between that ball and the quickfilver in one of the
glaffes, while the quickfilver in the other glafs commu¬
nicated with the ground.
When the eleftric fpark was made to pafs through
common air, included between fhort columns of a folu-»w
tion of litmus, the folution acquired a red colour, and
the air wras diminiflied conformably to what was ob-
ferved by Dr Prieitley. When lime-water was uled in-
Head of the folution of litmus, and the fpark was con¬
tinued till the air could be no farther diminilhed, not
the leait cloud could be perceived in the lime-water j
but the air w’as reduced to two thirds of its original
bulk; which is a greater diminution than it could have
fuffered by mere phlogiftication, aa,.that is very little more
than one-fifth of the whole.
The experiment was next repeated with fome impure
oxygen gas. The gas was very much diminiflied, but
without the leaft cloud being produced in the lime-
water, nor was any cloud produced when carbonic acid
gas was let up to it ; but on the further addition of a
little caullic ammonia, a brown fediment was immedi¬
ately perceived.
Hence we may conclude that the lime-water was
faturated by fome acid formed during the operation ;
as in this cafe it is evident that no earth could have
been precipitated by the carbonic acid gas alone,
but that the cauftic ammonia, on being added, would
unite with the carbonic acid, and thus becoming a rar-
bonate jvould precipitate the lime by double affiinity;
whereas, if the lime had not been faturated with an
acid, it would have been precipitated on the addition
of carbonic acid gas. As to the brown colour of the
fediment, it was probably owing to fome of the mer¬
cury having been diflblved.
When the impure oxygen gas was confined by foap
lees, the diminution proceeded rather falter then when
it was confined by lime-water ; for which reafon, as
well as on account of this lixivium containing a large
quantity of alkali in proportion to its bulk, it feemed
better adapted than lime-water for experiments delign-
ed to invelligate the nature of the acid produced. Ac¬
cordingly fome experiments were made to determine of
what degree of purity the oxygen gas flrould be, in
order
6p4 ELECT
Eleandt°f0r<*er t0 ^ d!.m'm!(I,ed mofi readily and in the greateft
illuftrated ^eSree > an^ it was found that when good oxygen gas
by experi- was empioyed, the diminution wTas but fmall 5 when
t ment. perfectly pure azotic gas was ufed, no fenfible diminu-
^ tion took place j but when five parts of pure oxygen
gat, and three of common air were employed, almoft
the whole of the gafes were made to dilappear. It mult
be confidered that common air confifts of one part of
oxygen gas mixed with between three and four of azo¬
tic gas, lo that a mixture of five parts of pure oxygen
gas and three of common air, was nearly the fame
thing as feven parts of oxygen gas and three of azotic
gas.
Having made thefe previous trials, Mr Cavendifh in¬
troduced into the tube a little foap lees, and then let
up fome oxygen gas and common air, mixed in the
above proportions, which rifing to the top of the tube
diftributed the foap-lees in the twro legs of the tube,
as faff as the air contained in it was diminilhed by the
eleilric fpark j continuing to add more of the fame
mixture till no further diminution took place j after
which a little pure oxygen-gas, and then a little com¬
mon air were added, in order to fee whether ceflation
of diminution was not owing to fome imperfection of
the proportion of the two kinds of air to each other,
but without efFeCt. The lixivium being then poured
out of the tube, and feparated from the mercury, feem-
ed to be perfectly neutralized, as it produced no change
on the colour of paper tinged with the juice of blue
flowers. Being evaporated to drynefs, a fmall quantity
of fait wras left, which was evidently nitre, as appeared
by the manner in which paper impregnated with a fo-
lution of it burned.
For more fatisfaClion, he tried this experiment over
again, on a larger fcale. About five times the former
quantity of foap lees were now let up into a tube of a
larger bore 5 and a mixture of oxygen gas and common
air, in the fame proportions as before, being introduced
by the apparatus reprefented in fig. 53. the fpark was
continued till no more air could be made to difappear.
The liquor when poured out of the tube, fmelled
evidently of nitrous acid. This fait was found by the
manner in which paper, dipped into a folution of it,
burned, to be true nitre. It appeared by the left of
muriate of baryta, to contain no more lulphuric acid
than the foap-lees themfelves often contain, wdiich is in
general very little j and there is no reafon to think
that any other acid entered into it, except the ni-
tri;.
R I C I T Y. Part III,
xsy tneie beautiful experiments was demonitrated Principles of
one of the moil: important faCts in modern chemiilry, Electricity
viz. that the nitric acid is compofed of oxygen and !lluftrate.d
azote. ^ by.expen*
The above experiments of Prieitley and Cavendiih,
were repeated on a large fcale by Hr Van Marum,
with the powerful machine in Teyler’s mufeum.
For this purpofe he ufed a cylindrical glafs receiver '
five inches long and an inch and a quarter in diameter, the gafes.
into which different forts of gafes were fucceflively in-
ferted, and were confined by quickfilver or water. To
a hole made in the bottom of the inverted glafs re¬
ceiver, an iron wire was faftened, the external part of
which communicated with a condu&or, which being
prefented to the prime conductor of the machine, re¬
ceived the fparks from it. In this difpofition of the
apparatus it evidently appears, that the fparks pafled
through the gas contained in the receiver, by going
from the inner extremity of the wire to the quickfilver
or water in which the receiver was inverted. With
this apparatus it was found, that oxygen gas, obtained
from mercurial red precipitate, loft one-twentieth of its
bulk ; but its quality was not fenfibly altered, as ap¬
peared from examining it with the eudiometer. This
experiment being repeated when the receiver was in¬
verted in lime water, and likewife in the infufion of
turnfole, there enfued no precipitation, nor change of
colour. On pouring out this air, the ufual fmell of the
eleftric fpark was very fenfibly perceived.
Nitrous gas wTas diminiflied to more than the half of
its original bulk ; and in that diminifhed fiate, being
mixed with common air, it occafioned no red colour,
nor any fenfible diminution. It had loft its ufual
fmell, and it extinguilhed a candle. In palling the
fparks through the nitrous gas, a powder was formed
on the furface of the quickfilver, which is a part of that
metallic fubftance diflblved by the nitrous acid.
Hydrogen gas, obtained from iron and diluted ful-
phuric acid, communicated a little rednefs to the tinc¬
ture of turnfole. The ftream of electricity through
this air appeared more red, and much larger, than in
common air, being everywhere furrounded by a faint
blue light.
The inflammable gas, obtained from alcohol and
fulphuric acid, was increafed to about three times its
original bulk, and loft a little of its inflammability.
Carbonic acid gas, from chalk and fulphuric acid,
was a little increafed in bulk by the adlion of eledtrici-
ty j but it was rendered lefs abforbable by water (x).
The
(x.) It was found by C. Monge, who carefully examined the gas produced by pafling eledtric fparks throucrh
car borne acid gas, that it had been rendered inflammable j and that the mercury employed to confine the gas
as well as the wires between which the fparks pafled, wrere oxidated. C. Monge fuppofed that the carbonic acid*
emp oyed had undergone no change, but that the water held in folution by it had been decompofed $ thus account¬
ing for the oxidation of the metals, and the generation of inflammable gas.
M. Theodore de Sauflure, not confidering C. Monge’s experiments as decifive, repeated them on a larger fcale.
He caufed to circulate for 18 hours, eledtric fparks in the bulb of a matrafs which contained 13 cubic inches of
pure carbonic acid gas, and without any mixture of water fuperabundant to that wdiich it might naturally hold
m folution. The mercury in wyhich the inverted matrafs was immerfed rofe to about the half of its neck. After
eledlnzation the metallic fluid was found oxidated black, as had been obferved by Monge and Prieftley ; but his
condudfors, which were of copper, wTere not fenfibly altered. The elaftic fluid had experienced a fmall dilatation,
which appeared to him not to exceed the tenth part of a cubic inch. He then made about a grain of water to
f afs in contact with the aeriform gas contained in the matrafs. He let it remain there for feveral days, without
2 perceiving
Chap. VII. ELECT
Principles of The gas obtained from fulphuric acid and char-
Ele&ocity coa| was a little, and black fpots were
b^ex^er^ ^orme^ on t^e °f the glafs receiver. Afterwards
yment.r * it was obferved, that only one-eighth part of the eleftri-
'—v——' fied gas was abforbed by water. It extinguilhed a
candle, and had very little fmell.
Muriatic acid gas feemed to oppofe in great meafure
the paiTage of the eledlric fparks, fince they would not
pafs through a greater length than 2|th inches of this
air. It was confiderably diminilhed, but the reft was
readily abforbed by water.
Fluoric acid gas was neither diminifhed, nor any
other way fenlibly altered, by the electric fparks.
Ammoniacal gas, extracted from pure ammonia, was at
lirft almoft doubled in bulk j then it was diminiihed
a little •, after which it remained without any aug¬
mentation or diminution. It became unabforbable
by water*, and by the contaft of flame it exploded,
like a mixture of hydrogen gas and a good deal of
common air.
Common air was laftly tried, and it was found to
give a little faint rednefs to the thnfture of turnfole j
becoming at the fame time fenfibly deoxidized. The
experiment was repeated thrice at different times, and
in each time after the eleflification it was examin¬
ed by the admixture of nitrous gas in Mr Fontana’s
eudiometer, and it was compared with the fame gas not
eleftrified 5 the latter always fullering the greateft di¬
minution. In the firft experiment the diminutions
were and 5 in the fecond, anci ? and
in the laft, ^4 and
On attempting to repeat Mr Cavendilh’s experi¬
ment defcribed above, in which he produced the nitric
acid by a mixture of oxygen with azotic gas j inftead
of a fyphon, the Doftor made ufe of a glafs tube one-
lixth part of an inch in diameter, clofed at one end, in¬
to which an iron wire, Troth of an inch in diameter,
had been inferted : into this tube, filled with mercury,
and fixed in a vertical pofition, was introduced the air
with which the experiment w'as to be tried. The oxy¬
gen gas wTas obtained from red preciptate, and had
been thoroughly purified by alkaline fairs, from any
acid it might have contained. With a mixture of five
R I C I T Y. 695
parts of this and three of common air, the tube wras Principles of
filled to the height of three inches, to which was add-
ed five-twelfths of an inch of lixivium, of the fame kind by experi_
with that ufed by Mr Cavendilh. The refult was, ment. ’
that, after tranfmitting through the tube a continued -v—
ftream of the electric fparks during 15 minutes, two
inches of the air were abforbed by the lixivium : more
air being introduced into the tube till it was filled to the
height of three inches, when it was again eleftrified.
This procefs was repeated till S^th inches of air had
been abforbed by the lixivium : this was nowr examined,
and found to be, in fome degree, impregnated with the
nitric acid ; but it wras very far from being faturated.
With the fame lixivium, of which a quarter of an inch
remained in the tube, the experiment was continued
till 14 inches more of air had been ablorbed j but its
diminution was not perceived to decreafe, though the
lixivium had now abforbed 77 meafures of air, each
equal to its own j whereas, in the experiment related
by Mr Cavendiflr, only 38 meafures of air w-ere ab¬
forbed by the alkali. But notwithftanding this great¬
er abforption, the lixivium wras yet far from being fa¬
turated.
The experiment was repeated with oxygen gas, ob¬
tained from minium, moiftened with the fulphuric
acid ; feven parts of this were mixed with three of
azotic gas, and lixivium added to the height of one-"
eighth of an inch. Here, as in the former experi¬
ment, the diminution continued without any decreafe ;
and the lixivium, after it had abforbed 22^th inches,
and confequently 178 times its own meafure of air,
was very far from being faturated with the nitric acid.
On this Dr Van Marum wrote to Mr Cavendifh j
and finding, by his anfwer, that this gentleman had
ufed oxygen gas, obtained from a black powder pro¬
duced by (baking mercury with lead, he requefted to
be informed of the procefs by which it is generated :
but Mr Cavendifh, not choofing to communicate this
at prefent, he determined to defer the repetition of the
experiment till this ingenious philofopher ftiould have
publifhed his mode of obtaining the oxygen gas ufed
in it.
Our author then goes on to fome experiments
made
perceiving any dilatation in the volume of the gafes, the refidue of the operation. He then moiftened with a
drop of water, which he introduced, the wThole infide of the matrafs j but in vain : the mercury conftantiy re¬
mained at the fame height. He, however, found, on abforbing by potafli the refiduum of the acid gas, that a
cubic inch of carbonic acid gas had difappeared, and had been replaced by a quantity nearly equal, or rather
fuperior, to the inflammable gas. The 20 cubic centimetres, occupied in the neck of the matrafs, a column four
inches in length •, and the acid gas, had the fuppofed explanation been juft, would have been dilated throuo-h all
that fpace. He then thought that this inflammable gas did not arife from the decompofition of the water, but
from that of the carbonic acid itfelf, by the metal. He indeed found that this gas was not hydrogen gas, but
carbonous gas perfeftly pure. He burnt zoo parts of it on mercury with about a third of oxygen gas. He did
not perceive water after this combuftion, which left for refiduum 77 parts of carbonic acid gas.
The dilatation which the latter experiences by ele&rization may be explained by the different denfities of the
carbonous gas and the carbonic acid gas. He was not able to verify the obfervation of C. Monge refpefting the
dilatation experienced by the carbonic acid gas, after ele&rization over mercury.
If it was not poflible to reduce entirely the acid gas into carbonous gas by thefe proceffes, it was becaufe the
the firft ft rata of metallic oxidation prefented an obftacle to further oxidation, by preventing the points of contafh
The developement of the carbonous gas produced therefore an analogous effect.
It refults then from his obfervations, that the change which carbonic acid gas undergoes by electrization does
not arife from the decompofition of the water, but from the partial decompofition of the carbonic acid gas,
which becomes carbonous gas, giving up a part of its oxygen to the metal introduced in thofe experiments.
696 ELECT
Principles ofmade by fuffering the ele&ric fpark to pafs in a con-
flluftrated t*nue<^ ftream through various kinds of air, enclofed for
by experi- PurP°fe t^6 little glafs tube ufed in the laft ex-
ment. periment.
—  ' Oxygen gas obtained the week before from red preci¬
pitate, being placed over mercury, and electrified for
30 minutes, was diminifhed by one-fifth, the furface of
the quickfilver foon began to be oxidated, and to¬
wards the end of the experiment the glafs tube was fo
lined with the oxide as to ceafe to be tranfparent. By
introducing a piece of iron, the eleCtric dream was
made to pafs through the air without immediately
touching the mercury : yet this was equally oxidated.
Two inches and three quarters of the fame kind of gas
being placed over water, and eleftrified in the fame
manner during half an hour, loft a quarter of an inch j
and being fufl'ered to Hand 1 2 hours in the tube, was
found to have lolt one-eighth of an inch more. This
was very nearly the fame diminution of the gas that
had taken place when it was eleftrified over mercury ;
but, in this cafe, the procefs appears to have been more
flow. The gas remaining after thefe experiments, be¬
ing tried by the eudiometer, did not difter from unelec¬
trified oxygen gas taken from the fame receiver.
To determine whether the gas retained any of the
acid employed in its production, the DoCtor repeated
the experiment with gas obtained from red precipitate,
confined by an infufion of turnfole, but could not per¬
ceive in it the leaft change of colour. He alfo elec¬
trified gas obtained from minium and the fulphuric
acid, placed over fome diluted acetate of lead 3 but
this was not rendered at all turbid.
Three inches of azotic gas being eleCtrified, during
the firft five minutes were augmented to 3 J-th inches,
and in the next 10 minutes to 3^th inches: fome
lixivium was then introduced to try whether this would
abforb it 3 but upon being eleCtrified 15 minutes, the
column rofe to the height of 3^th inches. It was fuf-
fered to ftand in the tube till the next day, when it
was found to have funk to its original dimenfions.
Nitrous gas, confined by lixivium, being eleCtrified
during half an hour, loft three quarters of its bulk 3 the
lixivium appeared to have abforbed a great deal of ni¬
tric acid 3 and the gas remaining in the tube did not
feem to differ from common azotic gas. Some of the
fame nitrous gas, confined by lixivium, was, by Hand¬
ing three weeks., di mini (lied to half its bulk, and this
refiduum alfo proved to be azotic gas.
Hydrogen gas obtained from fteel filings and the
diluted fulphuric acid, being confined by an infufion of
turnfole, was eleCtrified for 10 minutes without any
change of colour in the infufion, or any alteration
in the bulk of the air. The tube being filled with
the fame air to the height of 2! inches, and placed
in diluted acetate of lead, was expofed to the eleCtric
ftream during 12 minutes, in which time the enclofed
gas rofe to five inches 3 but the acetate remained perfect¬
ly clear. Three inches of inflammable gas, obtained
from a mixture of alcohol and fulphuric acid, on being
eleCtrified for 15 minutes, rofe to 10 inches; thus di¬
lated, it loft all its inflammability, and when nitrous gas
was added, no diminution enfued.
A column of ammoniacal gas obtained by heat from
pure ammonia, three inches high, was eleCtrified
^oqr minutes, and rofe to fix inches, but did not rile
1
R I C I T Y. Partlll.
higher when eleCtrified ten minutes longer. It appears Principles of
that this air is not expanded more by the powerful elec- Electricity
trie ftream from this machine than by the common fpark. ||,u^iate^
Water would not abforb this eleCtrified air, which was ment™'
in part inflammable. t——
The tube, being filled to the height of an inch with
ammoniacal gas, and inverted in mercury, was eleCtrifi¬
ed four minutes 3 in which time the tube was filled
with eight inches of gas, which proved to be equally
inflammable, and as little abforbed by wxiter as the am¬
moniacal gas.
The following experiment is Very curious. Two Curious ex¬
balloons, made of the allantoides of a calf, wrere filled periment
with hydrogen gas, of which each contained about two w’t*1 bi¬
cubic feet. To each of thefe was fufpended, by a^0^^ ^
filken thread about eight feet long, fuch a weight asge‘n r°‘
was juft fufficient to prevent it from rifing higher in*
the air 3 they were connefted, the one with the pofitive,
the other with the negative conduftor, by fmall wires
about 30 feet in length 3 and being kept near 20 feet
afunder, were placed as far from the machine as the
length of the wires would admit. On being eleftri-
fied, thefe balloons rofe up in the air as high as the
wire allowed, attraCled each other, and uniting as it
were into one cloud, gently defeended. 16s
The rarefaftion of air by the eleCfric explofion, is Ele&rical
well illuftrated by an experiment of Mr Kinnerfley,a,r
thus deferibed by Mr Cavallo. Fig. 54. PI. CLXXXIX. metp[‘te
reprefents an inftrument, which the inventor, Mr Kin-cLXXXIX.
nerfley, calls the eleEirical air thermometer, it being
very ufeful to obferve the effeCts of the eleCfric explo¬
fion upon air. The body of this thermometer confifts
of a glafs tube AB, about ten inches long, and nearly
two inches diameter, and clofed air-tight at both ends
by two brafs caps. Through a hole in the upper cap,
a fmall tube HA, open at both ends, is introduced in
fome water at the bottom B of the large tube. Through
the middle of each of the brafs caps, a wire FG, El, is
introduced, having a brafs knob within the glafs tube,
and by Hiding through the caps, they may be fet at any
diftance from one another. This inftrument is, by a
brafs ring C, fattened to the pillar of the wooden ftand
CD, that lupports it. When the air witbin the tube
AB is rarefied, if will prefs upon the wTater at the bot¬
tom of the tube, which will confequently rife in the
cavity of the fmall tube ; and as this wrater rifes higher
or lower, fo it lhowTs the greater or lefs rarefaCtion of
the air within the tube AB, which has no communica¬
tion with the external air.
If the water, when this inftrument is to be ufed, is
all at the bottom of the large tube, (i. e. none of it is
in the cavity of the fmall tube) it will be proper to
blow with the mouth into the fmall tube, and thus
caufe the water to rife a little in it 3 where, for better
regulation, a mark may be fixed.
Bring the knobs G1 of the wires IE, FG, into con-
taft with one another, then conned the ring E or F,
with one fide of a charged jar, and the other ring with
the other fide, by which operation a (hock will be
made to pafs through the wares FG, IE, i. e. between
the knobs El. In this cafe you wrill obferve, that the
wTater in the fmall tube is not at all moved from the
mark.
Put the knobs GI, a little diftant from one another,
and fend a Ihock through them as before, and you will
fee
Chap. VII. ELECT
Principles of fee that the fpark between the two knobs, not only dif-
Eletfricity places, but rarefies confiderably the air $ for the water
will be fuddenly pulhed almoft to the top of the fmall
'meritn' tube, and immediately it will fubfide a little, as for
—V—^ inltance as far as H which is occafioned by the Hid¬
den difplacing and replacing of the air about the place,
where the fpark appeared within the tube AB. After
that the water has fubfided fuddenly from the firft
rifing, it will then gradually and llowly come down to
the mark at which it flood before the explofion •, which
is the effeft of the air that was rarefied, and which gra*-
dually returns to its former temperature*
If this experiment be made in a room, where the de¬
gree of heat is variable, then proper allowance muft be
made for this circumflance, in eftimating the event of
the experiment *, for the electrical air thermometer is
affefted by heat or cold in general, as well as by that
caufed by an eleftric fpark.
Mon111?0" t^e year 17^9» Meffrs Pacts, Van Trooftwyk, and
water° Deiman, the three affociated Dutch chemifls, as they
are generally called, fent a letter to M. de la Methrie,
giving an account of fome experiments, which they,
affifted by Mr Cuthbertfon, had made on the effect of
palling a ftream of eleftricity for a confiderable time
through water. Their letter was printed in the Jour¬
nal de Phyjique for that year 5 but the account is too
long to be inferted here $ we lhall, therefore, copy the
following fuccinct account of the experiment by Dr
Pearfon.
The apparatus employed was a tube 12 inches in
length, and its bore was one-eighth of an inch in diame¬
ter, Englilh meafure $ which was hermetically fealed at
one end, and, while it was fealing, an inch and a half
of gold or platina wire was introduced within the tube,
and fixed into the clofed end, by melting the glafs a-
round the extremity of the wire. Another wire of
platina, or of gold, with platina wire at its extremity,
immerfed in quickfilver, was introduced at the open
end of the tube, which extended to within five-eighths
of an inch of the upper wire, which, as was jufl faid, was
fixed into the fealed extremity (u).
The tube was filled with diftilled water, which had
been freed from air by means of Cuthbertlon’s laft im¬
proved air-pump, of the greateft rarefying power. As
the open end 6f the tube wras immerfed in a cup of
quickfilver, a little common air was let into the con¬
vex part of the curved end of the tube, with the
view of preventing frafture from the eleftrical dif-
charges.
The wire which palled through the fealed extremity
Vol. VII. Part II.
ft 1 C I T 697
was fet in contaft with a brafs infulated bail j and this Principles of
infulated ball was placed at a little diftance from the
prime conductor of the eledtrical machine. The wire ^ eXperi-
of the lower or open extremity, immerfed in quick- ment.
lilver, communicated by a wTire or chain wnth the ex-1 v-—^
terior coated furface of a Leyden jar, which contained
about a fquare foot of coating *, and the ball of the jar
was in contadt with the prime conductor.
The eledtrical machine confirted of two plates of 31
inches in diameter, and fimilar to that of Teyler. It
polTeffed the power of caufing the jar to difeharge itfelf
25 times in 15 revolutions. When the brafs ball and
that of the prime condudlor were in contadl, no air or
gas was difengaged from the water by the eledtrical dil-
charges $ but on gradually increaling their diftance
from one another, the polition was found in which gas
was difengaged, and wdiich afeended immediately to the
top of the tube. By continuing the difeharges, gas con¬
tinued to be difengaged, and afeend, till it reached near¬
ly to the lower extremity of the uppeis. wire j and then
a difeharge occafioned the wThole of the gas to difappear,
a fmall portion excepted, and its place was confequently
fupplied by wrater.
The reiiduary portion of gas being let out after each
experiment, and the difeharges being continued in the
fame water, this refiduary gas wras left in fmaller and
fmaller quantity 5 fo that after four experiments, proba¬
bly made on the fame day, it did not amount to more
than 1 80th of the bulk cf gas which had been produced.
If it had been poflible to pafs eleftric fparks through
this very fmall quantity of gas a fecond time, or
oftener, it was fuppofed it would have been diminilhed
ftill more. But when the tube had been left for a
night only filled with water, the refiduary gas was in
greater quantity than after the laft experiment the pre¬
ceding day (x).
It was concluded that the gas produced by the elec¬
trical difeharges was oxygen and hydrogen gas, from de¬
compounded water :
1. Becaufe no other gas hitherto known inftant*
ly difappears on paffing through it an electric fpark.
2. The gas obtained muft have been the oxygen and
hydrogen of decompounded water, becaufe they were in
exactly thofe proportions in which by combination they
reproduce water j the trilling refidue being confidered
to be merely a portion of air which had been diffolved in
the water.
3. Liquids which are not compounded of hydrogen
and oxygen, as fulphuric and nitric acids, afforded gas
by the eledtric dilcharges, but which did not difappear
4 T on
(u) In another part of Mr Van Trooftwyk’s memoir it is ftated that the diftance was an inch and a quarter from the
end of the upper wire to the top of the lower wire J and that the diftance between the infulated ball and
prime condudlor was at firft three-fourths of an inch, but that afterwards it was increafed to an inch. Although
the wire fattened into the top of the tube was faid to be an inch and a half in length, it is obferved, that when
a column of three-eighths of an inch of air was collected, it wras almoft at the extremity of the upper wire, From
thefe and other inaccuracies, it will be made appear, that no one, from the account pubfilhed, has been able to re¬
peat the experiment.
(x) In at leaft fifty experiments I have never feen the refidue of gas lefs than one-fortieth of the gas produced,
although the wrater had been freed from air by the moft effectual means. But Mr Schurer (Annales de Chimie,
tom. v. p. 276.) teftifies that he faw Mr Van Trooftwyk make the experiment ; and that after it was repeated
many time'', on the fame parcel of water, there was no refidue at all. I have very good grounds for believing, that
this is one of the number of inaccuracies in the account publilhed of this fubjeCL
69« _ - ELECT
liScuf j"r,paffing throu§1’ !t ai! 'l*aric fpark ; but which did
illuftrated “llaPPear on adding to it nitrous gas over water. Mr
by experi- ^c*lurcralio afferts, on the authority of Mr Van Trooft-
rnent. wyck, that even liquid muriatic acid, which contains
' v a verJ ^arge proportion of water, affords hydrogen gas
only the oxygen being abforbed by the muriatic acid,
i7o and becoming oxy-muriatic acid.
Br Pear- ^ Di Peaifon repeated the above experiments i and has
riments^" §1V^n a[1.amP^e detail of the manner in which he con¬
ducted his experiments, and of their refult. Our limits
will not permit us to give the paper of this ingenious
cnemilhat length : we lhall, therefore, prefent our readers
with a brief abftraCt of it, referring them for the origi¬
nal to Nicholfon’s Journal for September, October, and
November 1797, or the Philofophical Tranfadions for
the fame year.
Dr Pearfon remarks that eleCtric difeharges may be
employed in twTo manners to decompound water, viz. by
what has been termed the interrupted explofion, which
was Mr Van Trooftwyk’s method, and the uninterrupt¬
ed or complete explofton.
The Dodor lays down the following requifttes for
fucceeding in this experiment by the interrupted ex¬
plofion.
1. The eledlrical machine mujl pojjejs fufficient power.
Dr Pearfon employed a plate machine, conftruded by
Cuthbertfon, wThich he confiders as preferable to a cylin¬
drical machine.
2. The Leyden jar mujl have a fufficient quantity of
coated furface. I he Dodor found by experience that
the pioper quantity was about 150 or 160 fquare inches,
with a proportional prime condudor.
3. The di/lance between the infulated ball and the prime
conduBor mujl always be lefs than the di/lance between
the extremities of the wires.
4. Ihe extremities of the upper and under wire within
the tube tnufl be at a certain difance from one another.
The diftance which the dodor generally found to
anfwer beft, was about five-eighths or feven-eighths of
an inch.
5. The upper wire fixed into the clofed extremity of the
tube mujl be of a proper length and thicknefs. The dia-
meter of the upper wire cannot perhaps be too fmall,
and the Imaller the diameter of the tube, the longer this
wire may be.
6. The tubes mujl be of a proper length and diame¬
ter. The Dodor found the proper length to be nine
or ten inches, exclufive of the curved part. The dia¬
meter ftiould not be more than one-eighth, or lefs than
one -twelfth of an inch.
To fucceed by the complete or uninterruptedexplofion
Dr Pearfon ufed the following apparatus.
1. A tube about four or five inches in length, and
one-fifth or one-fixth of an inch in diameter } one end
of which was mounted with a brafs cap, and into the o-
ther, which was hermetically fealed, wras fitted a platina
wire of about 1 -40th of an inch in diameter, extend¬
ing into the brafs cap, fo as to be almojl in contad
with it.
2. He alfo employed a tube five inches long and half
an inch wide, either blown into a funnel at one end or
having a brafs funnel fitted to it, and inverted in a brafs
dilh 5 a wire, fuch as the laft, is fealed into the other end
and nearly touches the brafs dilh.
The proper diftaqce between the wire and dilh jnuft
R 1 c I T Y. Part HI.
be found by trials. In the Dodor’s experiments it was Principles of
about one-twentieth of an inch. -kle&ricity
3. The Leyden jar employed muft contain about 1 co ''llu<,:rate{l
fquare inches of coating.
4. I he diftance between the infulated ball and the L 1 - 1
prime condudor was about half an inch.
. hrom his experiments Dr Pearfon draws the follow¬
ing conclufions.
1 he mere concuflion by the eledricr difeharge?, ap¬
pears to extricate not only the air diffolved in water,
which can be feparated from it by boiling and the air-
pump, but alio that which remains in water, not-
withftanding thefe means of extricating it have been
employed.
I he quantity of this air varies in the fame, and in
difterent waters, according to circumftances. New-River
water from the ciftern yielded one-fifth of its bulk of
air, when placed by Mr Cuthbertfon under the receiver
of his molt powerful air-pump 5 but in the fame fituation,
New-River water taken from a tub expofed to the at-
mofphere for fome time yielded its own bulk of air.
Hence the gas procured by the firft one, two, or even
three hundred explofions in water containing its natural
quantity of air, is diminilhed very little by an eledric
fpark.
The gas thus feparable from water, like atmofpheri-
cal air, confifts of oxygen and nitrogen, or azotic gas j
"which may be in exadly the fame proportions as in at-
molpherical air : for the water may retain one kind of
gas more tenacioufly than the other and on this account
the air feparated may be better or worfe than atmofphe-
rical air at different periods of the procefs for extrica¬
ting it.
With regard to the gas, which inftantly difappears on
palling through it an eledric fpark, its nature is Ihewn
by (a) this very property of thus diminilhing • and by
the following properties t
(b) A certain quantity of nitrous gas inftantly difap-
peared, apparently compofing nitrous acid, on being add¬
ed to the gas (a).
Oxygen gas being added to the refidue after fatura-
tion with nitrous gas, and an eledric fpark being ap¬
plied to the mixture of gaffes, well dried, a confiderable
diminution immediately took place, and water was pro¬
duced.
(c) Combuftion from hydrogen and oxygen gas took
place when the tube was about three-fourths full of gas,
■which was confirmed by palling an eledric difeharge,
under the fame circumftances, through a mixture of hy¬
drogen and oxygen gas.
(d) Combuftion from hydrogen and oxygen gas took
place when the points of the compaffes were accidental¬
ly applied to the part of the tube containing gas j which
was confirmed by palling a difeharge, under the fame
circumftances, through a mixture of hydrogen and oxy¬
gen gas, while the points of the compaffes were applied
to the tube.
(e) The obfervations made of the kindling of gas, in
fmall quantities, from time to time, during the procefs
of obtaining it, particularly while it was afeending in
chains of bubbles, or was adhering to the funnel of the
tube, confirm the evidence in favour of this gas being
hydrogen and oxygen gas. Fufi^nof
The eleBric fpark fifes and oxidates metals. Themetalsby
firft experiment to afeertain the adion of eledricity on the ele&ric
metals fPark*
Chap. VIL
Principles of metals Was, we believe, made by Dr Franklin. The me-
f/luftrated W^C’1 made the fpark fafe metals was by
hy esperi- Putting tbin pieces of them between two panes of glafs
ment. bound fall together, and fending an electric (hock through
w— v them. Sometimes the piece of glafs by which they
were confined, would be fhattered to pieces by the dif-
charge, and be broken into a kind of coarfe fand, which
once happened with pieces of thick lookiiig-glafs j but
if they remained whole, the piece of metal would be
milling in feveral places where it had lain between them,
and inltead of it, a metallic ftain would be feen on
both the glalles, the Itains on the under and up¬
per glafs being exactly fimilar in the minuteft ftroke.
A piece of gold-leaf ufed in this manner appeared
hot only to have been melted, but even vitrified, as the
Dodior thought, or otherwife fo driven into the pores of
the glafs, as to be protected by it from the adlion of the
ftrongeft aqua-regia. . Sometimes he obferved that the
metallic ftains would fpread a little wider than the
breadth of the thin pieces of metal. True gold, he ob¬
ferved, made a darker ftain, fomewhat reddilh, and fil-
Ver a greenilh Item.
Mr Cavallo gives the following directions for fufing
metallic wirest
Conned with the hook, Communicating with the out-
iide coating of a battery, containing at leaft thirty fquare
feet of coated furface, a wire, that is about one-fiftieth
part of an inch thick, and about two feet long j the o-
ther end of it miift be faftened to one end of the dif-
charging rod j this done, charge the battery, and then by
bringing the difcharging rod near its wires, fend the ex-
plofion through the fmall wire, which, by this means, will
be made red hot, and melted, fo as to fall upon the floor
in different glowing pieces. When a wire is melted in
this manner, fparks are frequently feen at a confiderable
ffiftance from it, which are red hot particles of the metal,
that by the violence of the explofion are fcattered in all
diredions. If the force of the battery is very great, the
wire will be entirely difperfed by the explofion, fo that
none of it can be afterwards found.
By repeating this experiment with wires of different
metals, and the fame force of explolion, it will be found
that fome metals are more readily faffed than others, and
fome not at all affeded j which ihows the difference of
their conduding power. If it be required to melt fuch
particles of metals, that cannot ealily be drawn in wires,
as ores, grains of plathta, &c. they may be fet in a train
upon a piece of wax ; this train may be inferted in the
circuit, and an explofion may be fent through it,
which, if it be fufficiently ftrong, will melt the metal¬
lic particles, as well as the wires : or, if the quantity tb
be tried be large enough, it may be confined in a fmall
tube of glafs.
If a wire be ftretched by weights, and a ftiock be made
to pafs through it, fo as to render it juft red hot, the
wire after the explofion will be found confiderably in-
creafed in length, but if the wire be left loofe it will
be found after a fimilar explofion confiderably ftior-
* Cat alio'S tened *.
iSleflricity, If a wire be melted upon a piece of glafs, the glafs will
v°L i. after the explofion be found marked with all the prifma-
p,3IC* tic colours.
Ihe wire may be formed into globules by Inclofing
it in a glafs tube about a quarter of an inch in diameter,
and fending the charge of a battery through it. The
.. , . . . 699
Wire thus melted, will run into globules, which will ad-Prmciplesof
here to the inner furface of the tube, and may be eafily Ele&ricity
feparated from it. On examination they will be found
to be hollow, and are the metal in its leaft ftate of oxi- merit?1
dation. . .
Some nicety is required in this experiment, as if the
charge be too fmall, the globule will not be well form¬
ed, and if it be too great, the metal will be fo much
oxidated as to be diifipated in fmoke.
If a piece of metal be fixed upon each of the knobs
of the univerfal difcharger, or upon the extremities of
the wires that fupport thefe knobs, fo that their furfaces
may come fufficiently near each other for the charge of
a battery to be paffed betw-’een them, and if a difcharge
be then made, a fpot and coloured circles will be form¬
ed upon each metallic lurface, which are evidently ow¬
ing to a partial oxidation of the metal.
In order to exhibit coloured rings upon the furface
of metals, place A plain piece of any of the metals upon
one of the wires of the univerfal difcharger, and upon
the other wire fix a ffiarp-pointed needle, with the point
juft oppofite to the furface of the metal then connect
one wire of the difcharger with the outfide of a bat*
tery, and the other with the difcharging rod, &c. In
this manner, if explofions be repeatedly fent either from
the point to the piece of metal, or from the latter to
the former, they will gradually mark the furface of the
piece of metal oppofite to the point, with circles, con-
fiftmg of all the prifmatic colours 5 wffiich are evidently
occafioned by laminae of the metal, raifed by the force
of the explofions.
Thefe colours appear fooner, and the rings are clofer
to one another, wffien the point is nearer to the furface
of the metal. The number of rings is greater or lefs
according as the point of the needle is more ffiarp or
more blunt ; and they are reprefented equally wrell up¬
on any of the metals.
I he point of the needle is alfo coloured to a confider¬
able diftance ; the colours upon it returning in circles
though not very dillinctly. This is an experiment of Dr
Prieftley. v x
But the moll fplendid experiments on the fufion of Van Mr-
metals by fele&ricity have been made by Dr Van Ma- rum’s ex-
rum. He firft tried the effea of a battery containing ptr'a'ents
130 fquare feet of coated furface. With this extraordinary metalsl'^
power, he melted an iron wire 15 feet long and T-fT of
an inch in diameter ; and another time melted a wire of
the fame metal 25 feet long and T^th of an inch in
diameter.
He afterwards added to the battery 90 jars, each of
the fame lize with the former, fo that"his grand bat¬
tery now formed a fquare of 15 feet, and contained 22c
fquare feet of coated glafs. He caufed wires of differ¬
ent metals to be drawm through the fame hole, of one-
thirty-eighth part of an inch in diameter, and obferved
how many inches of each could be melted by the ex¬
plofion of his battery ; taking care in all thefe experi¬
ments to charge it to the fame degree as afcertained by
his elearometer. The refults w^e're as follows :
Of lead he melted 120 inches <
Of tin 1 go
Of iron - r
Of gold 3.*
Of jilver, copper, and brafs, not quite a quarter
of an inch.
4 T 2 Thefe
electricity.
7 oo ELECT
Principles of TheTe feveral lengths of wire, of the fame diameter
Pledricity me{teci by equal exploflons, indicate according to our
if 'es^erf author, the degree in which each metal is fufible by the
^incntn eleftrical difeharge $ and if thefe be compared with the
  y——' fufibility of the fame metals by fire, a very confiderable
difference will be obferved. According to the experi¬
ments of the academicians of Dijon, to melt tin required
a 'heat bf 17 2 degrees of Reaumur’s thermometer.
R
Lead
Silver
Gold
Copper
Iron
220
43°
563
630
696 (y).
Thus tin and lead appear to be equally fufible by elec¬
tricity, but not by fire : and iron, which by fire is lefs
fufible than gold, is much more fo by the eledrical ex-
plofion.
When iron wire is melted by the explofion of the
battery, the red hot globules are thrown to a very con¬
fiderable diffance, fometimes to that of 30 feet j it is
however remarkable, that the thicker the wire is which
is melted, the further are the globules difperfed •, but
this is accounted for, by obferving, that the globules
formed by the fufion of the thinner wires, being final-
ler, are lefs able to overcome the refiftance of the air,
and are therefore fooner flopped in their motion.
Two pieces of iron wire being tied together, the fu¬
fion extended no further than from the end conneded
with the infide coating of the jars to the knot •, though
wire of the fame length and thicknefs, when in one
continued piece, had been entirely melted by an equal
explofion.
When a wire was too long to be melted by the dif¬
eharge of the battery, it w7as fometimes broken into
feveral pieces, the extremities of which bore evident
marks of fufion; and the effed of eledricity in fhorten-
ing wire, was very fenfible in an experiment made on
18 inches of iron wire Trrth of an inch in diameter,
which by one difeharge loft a quarter of an inch of its
length. An explofion of this battery through very
fmall wires, of nearly the greatefl length that could be
melted by it, did not entirely difeharge the jars. ^ On
tranfmitting the charge through 50 feet of iron ware of
th of an inch in diameter, the dodor found that
the refiduum was fufficient to melt two feet of the fame
wire ; but this refiduum was much lefs when the wire
was of too great a length to be melted by the firfl dif¬
eharge. After an explofion of the battery through 180
feet of iron wire of equal diameter with the former,
the refiduum was difeharged through 12 inches of the
fame wire which it did not melt, but only blued.
Twenty-four inches of leaden wire -^th of an inch
in diameter, wTere entirely oxidated by an explofion of
this battery j the greater part of the lead rofe in a thick
I c I T Y. Fartin:
fmoke, the remainder was flmck down upon a paper Principles of
laid beneath it, where it formed a Haiti which refem-
bled the painting of a very dark cloud. When fhorter •i!ultrat“d
wires were oxidated, the colours were more varied. In ^nent.'
Dr Van Marum’s wrork a plate is given of a ilaln v~
made by the oxidation of this wire, in which the cloud
appears varioufly ihaded wfith different tints of green,
gray, and browm, in a manner of which no adequate
defeription can give an idea.-
On difeharging the battery through 8 inches of tin-
wire -jVth of an inch in diameter, extended over a flieet
of paper, a thick cloud of blue fimoke arofe, in which
a number of filaments of oxide of tin wrere difeernibley
at the fame time a great number of red hot globules of
tin, falling upon the paper, were repeatedly throw-n up
again into the air, and continued thus to rebound from
its furface for feveral feconds. The paper was marked
with a yellowiffi clouded ftain immediately under the
wire, and with flreaks or rays of the fame colour iffu-
ing from it in every direction j fome of thefe formed
an uninterrupted line, others wTere made up of feparate
fpots. In order to be certain that the colour of tbefe
ftreaks w7as not caufed by the paper being fcorched, the
experiment wTas feveral times repeated, when a plate of
glafs and a board covered with tin were placed to re¬
ceive the globules. Thefe, however, were ftaine
exadlly like the paper. On oxidating five inches of the
fame kind of wire, the red hot globules were thrown
obliquely to the height of four feet, which afforded an
opportunity of obferving that each globule, m its courfe,.
diffufed a matter like fmoke, which continued to ap¬
pear for a little time in the parabolic line deferibed by
its flight, forming a track in the air of about half an
inch in breadth.
Dr Van Marum attributes the clouded ftain, imme¬
diately under the wire, to the inftantaneous oxidation
of its furface j whereas the remainder of the metal is
melted into globules, which while they retain their
glowing heat, continue to be fuperficially oxidated, and
during the procefs, part with this oxide in the form of
vapour.
Phenomena fomething fimilar to the above, were ob¬
ferved on the oxidation of a wire of equal parts of tin
and lead, eight inches long, and -^d of an inch in dia¬
meter. This alfo was melted into red globules, which
were repeatedly driven upwards again from the paper
on which they fell, and marked it with ftreaks of the
fame kind, but of a brown colour, edged with a yel¬
low tinge. Some of thefe globules, though apparently
not lefs hot, moved with lefs velocity than others, and
and were foon flopped in their courfe by their burning
a hole in the paper. In this cafe a yellow matter was
feen to rife from their furface to the height of one or
two lines, and extended itfelf to the width of a quarter
of an inch. This matter continued during five or fix.
feconds.
(y) According to the experiments of Mr Wedgew'ood with his Pyrometer, the following are the degrees of heat
computed in degrees of Fahrenheit’s fcale that are required to fufe certain metals.
Brafs
Swedifli copper
Fine filver
Fine gold
Call iron
38o7°
4587
4717
5237
39977
Vid. Phil Tranf. vol. Ixxii.
ELECTRICITY.
Chap. VII.
principlesof feconds, to hTue from tlie glooules, and formed\m their
ElecTncity fm-face a hind of efflorefcence, refembling the flowers
iHuitrated o£ produced by the fo/fa-terra. The globules,
k'inent n~ from which this efflorefcence had iffued, were found to
be entirely hollow, and to confift only of a thin fliell.
When this mixed metal is oxidated with a lefs charge
of battery, it leaves a ftain upon the paper, fomething
fimilar to that made by lead, and does not run into
globules.
Dr Van Marum has alfo given plates of the ftains
made upon paper by the oxidation of iron, copper,
brafs, filver, and gold. Thofe made by copper and
brafs wire, are uncommonly beautiful, and are varie¬
gated with yellow, green, and a very bright brown.
Eight inches of gold wire, of ^th of an inch diame¬
ter, were, by the explofion reduced to a purple fub-
ftance, of which a part rofe like a thick imoke, and
the remainder on the paper, left a ftain diverfilied with
different (hades of this colour. Gold,- filver, and cop¬
per, cannot eafily be melted into globules. Our author
has once accidentally fucceeded in this •, but it required
a degree of electrical force ib very particular, that the
medium between a charge, which only broke the wire
into pieces, and one which entirely oxidated it, could
not be afcertained by the electrometer.
Dr Van Marumlfound, as might be expected, that
the eleCtric fpark did not oxidate metals when confined
in any gas which did not contain oxygen. On expo-
fing wires of lead, tin, and iron, to the ele&ric fpark
from the difcharge of a battery, while the metals were
confined in air deprived of oxygen, by the burning
of inflammable bodies in it, he found that the firft was
reduced to a fine pow'der, which upon trial with nitric
acid appeared to be merely lead 5 the two other metals
were melted into fmall globules. He found that in ge¬
neral metals were not more highly oxidated in pure
oxigenous gas than in common air, except that lead
was reduced to a fine yellow oxide, perfectly refembling
. maflicot.
In nitrous gas, oxidation took place as eafily as in
common air or in oxigenous gas.
His method of making thefe experiments rvas as fol¬
lows. He confined the gas in w7hich he wTas to fubjeCt
the metal to the explofion, in a glafs- cylinder fix inches ■’oneip!e- oi
high and four inches in diameter, clofed at the upper ^^ted
end with a brafs plate-, from the centre of this plate ^ expen-
was fufpended the wire on which the experiment was ment.
made. The cylinder w'as fet in a pewter difh filled ^
wuth w^ater and to prevent its being broken by the
expanfion of the air, its low-er edges were fupported by
two pieces of wood half an inch high. The lower end
of the wire refted on the difh, which was connefted
with the outfide coating of the battery.
On fubmitting metallic wires to the aftion of the
eledlric fpark while confined in wTater, he found that
the water w-as decompofed, the metal being oxidated,
and a portion of impure hydrogenous gas being difen-
gaged (z). . . *73
Exper.—To burn a metallic’vcire in oxygen gas, by'To burn
the eieclric/park. ox^ en rr
The apparatus for this experiment is reprefented atoxysen 0
fig. 55. It confifts of a glafs jar for holding the gas, fit¬
ted to the bottom C, fo that it may eafily be taken out.
Into the bottom is fartened a brafs knob B, and a wire
paffes through the top of the jar furnifhed with a ball at
A, and a knob within the jar as D, into which the piece
of wire, twilled in a fpiral form, is to be inferted.
The jar, thus fitted up with the wire, is to be filled
with oxygen gas, obtained from the black oxide of man-
ganefe as deferibed under Chemistry; and on pafling
the charge of a fmall Leyden phial through the ware
A, an explofion will take place between the knob
and the extremity of the fmall wire, by which this will--
be inflamed, producing a moft brilliant and beautiful
appearance.
When the eleRric fparh is pajfed through a metallic *74
oxide, the oxide is reduced to the metallic Jiate.
This was effefted by Sign. Beccaria, by making the
fpark pafs between two furfaces of the oxide. In this
way he reduced feveral of the metallic oxides, among HBtccari*^
others, that of zinc. He alfo obtained pure mercury,
from the red fulphuret or cinnabar, f _ '
The eleRric fpark renders bodies luminous, and makes -j-q jiuirni-
opaque fibjlances appear tranfparent. nate water*
Exper. 1.—ConneCt one end of a chain with the out¬
fide of a charged phial, and let the other enjd lie on
the-
(z) Although there was good- reafon to fuppofe that the powders produced in the above experiments were real
oxides of the metals, yet they had not been proved to be fo by any fatisfaCtory experiment. Dr Van Marum
and his ingenious coadjutor (Mr Cuthbertfon), began a fet of direCt experiments for the purpofe of afeertaining
this point; but the doCfor was foon difeouraged by the breaking of apparatus, and nothing fatisfaClory was done.
Since Mr Cuthbertfon’s return to London, he has carried into execution a feries of experiments which he had
projeCfed in Holland, and by thefe he has fully proved that metaLs exploded by the eleCtric fpark abforb oxygen.'
from the air and become oxidated, more readily than when fufed by ordinary fire. We cannot pretend to give
any thing like an account of thefe experiments in this note; they are publifhed at length in Nicholfon’s Journal
for July 1801. The following are Mr Cuthbertfon’s general conclufions.
“ From the refult of the foregoing experiments, it may be fafely concluded that all the duClile metals can by
eledric difeharges be fublimed and converted into proper oxides, by abforbing the oxygen from the atmofphere,
and although fome of the metals refifl the aftion of common fire, and require different folvents to convert them
into oxides, yet they all yield to the aCtion of eleftricity.
It is remarkable that platina, though it refills the aCtion of common fire, is more eafily fufed by eleClric dif¬
eharges than copper, filver, or gold, and feems to be as greedy of oxygen as any of the other metals; but thefe
experiments have not been fufficiently extenfive to fettle the laft mentioned property.
It is well known that all metals which are fublimable by common fire, abforb oxygen in different degrees, and
likewife in different proportions, according to the degrees of heat employed; this leems to take place alfo when
they are fublimed by eieclric difcharges, but the proper degree of difcharge for each metal remains for in-
■vefligation.
JO 2
I nr.c pu softhe table. Place the end of another piece of chain at
the durance of about a quarter of an inch from the
lormer j and fet a glals decanter of water on thefe fepa-
rated ends. On making the difcharge, the water will
appear perfectly luminous.
. ele(^ric fpark may be rendered vifible in water,
in the following manner. Take a glafs tube of about
KLECTftICITY.
Eledlricit
by experi¬
ment
176
To
nate e^pfs.
Pl-'te
’77
. , an inch ln diameter, and fix inches long 5 fill it
Mitn water, and to each extremity of the tube adapt a
cork, which may confine the water j through each cork
inlert a blunt wire, fo that the extremities of the wires
within the tube may be very near one another 5 then on
connefhng one of thefe wires with the coating of a fmall
charged phial, and touching the other wire with the
knob of it; by which means the (hock will pafs through
the. wires, and caufe a vivid fpark to appear between
their extremities within the tube. The charge in this
experiment muft be very weak, or there will be danger
of burfting the tube.
Exfier. 2.—Fig. 56. reprefents a mahogany Hand, fo
rn.ie conltructed as to hold three eggs at greater or fmaller
CLXXXIX. d^ance, according to the pofition of the Hiding pieces.
A chain C is placed at the bottom, in fuch a manner
as to touch the bottom of the egg at B with one end,
and with its other the outfide coating of a charged jar.
The Hiding wire A at top is made to touch the upper
e&§ ? and the diflance of the eggs afunder fliould not
exceed the quarter or eighth part of an inch. The
elechic fpark, being made to pafs down by means of
tile difcharging rod through the wire and ball at A,
will in a darkened room render the eggs very luminous
and tranfparent.
Expci\ 3. Place an ivory ball on the prime con¬
ductor of the machine, and take a ftrong fpark, or fend
the charge of a Leyden phial through its centre, and
the ball will appear perfectly luminous 5 but if the
charge be not paffed through the centre, it will pafs
over the furface of the ball and fmge it. A fpark
made to pafs through a ball of boxwmod, not only il¬
luminates the whole, but makes it appear of a beauti¬
ful crimlon, or rather fine fcarlet colour.
Exper. 4. Gold-leaf or Dutch metal may be ren-
dered luminous by difcharging a fmall Leyden phial
through it. A flrip of gold leaf, one-eighth of an inch
in breadth, and a yard long, will frequently be illumi¬
nated throughout its whole extent, by the explofion of
a jar containing two gallons. This experiment may be
beautifully diverfified, by laying the gold or filver leaf
on a piece of glafs, and then placing the glafs in wa¬
ter ; for tne whole gold leaf wdll appear moft brilliant¬
ly luminous in the water, by expofmg it thus circum*
ftanced to the explofion of a battery.
Exper. 5.—The natural, or what anfwers better, the
artificial Bolognian Hone reduced to powder, (common¬
ly called Canton's phofphorus') may be illuminated by
the electric fpark in a more perfeft manner than by the
rays of the fun. The method of making this experi¬
ment is thus related by IVIr Cavallo,
Put fome of thi§ powTder in a clear glafs phial, and
flop it with a glafs Hopper, or a cork and fealing-wax.
If this phial be kept in a darkened room (which for
this experiment mufl be very dark) it will give no
light; but let two or three Hrong fparks be drawn
from the prime condu&or, wLen the phial is kept at
about tw’o inches diflant from the fparks, fo that it may
3 -
^8
To illumi¬
nate v. an
ton’s phof¬
phorus.
, r fart III.
e exp0iCd t0 tfiat llght and this phial will receive the Principles 0f
tight and. afterwards will appear illuminated for a con- Eiedtricity
Uderable time. iliuilrated
This powder may be fluck upon a board by means by experi*
°( the ^hke of an egg» as to reprefent figures of
planets, letters, or any thing elfe, at the pleafure of
the operator, and thefe figures may be illuminated in
the dark, m the fame manner as the above-defcribed
phial.
. A beautiful method of exprefling geometrical figures
with the above powder, is to bend fmall glafs tubes, of
a out the tenth part of an inch diameter, in the fliapes
of the figure defired, and then to fill them with the
phofphonc powder. Thefe may be illuminated in the
manner defcnbed ; and they are not fo fubjeft to be
IpcHlcd, as the figures reprefented upon the board fre¬
quently are.
. Th^belm^h°d of dluminating this phofphorus, and
that Mr W. Canton generally uled, is to difcharge a
Imail electric jar near it.
Paper after being made dry and rather hot, marble,
oyfter fhells, and moft calcareous fubftances, efpecially
when burned to lime, have the property of being il¬
luminated by the light given by the difcharge of a jar,
though not fo much as the above-mentioned powder.
Put the extremities of two wares upon the fiirface of
a card, or other body of an eleftric nature, fo that they
may be in one dire&ion, and about one inch diftance
from one another 5 then, by connecting one of the
wares with the outfide of a charged jar, and the other
wire wath the knob of the jar, the ftiock will be made
to pafs over the card or other body. If the card be
made, very dry, the lucid track between the wires wall
be vifible upon the card for a confiderable time after
the explofion. If a piece of common writing paper
be ufed inftead of the card, it wall be tom by the ex-
ploiion into very fmall bits.
When the eledric difcharge is paffed through a lump
of fugar,. the fugar is rendered perfectly luminous, and
will retain the light for a confiderable time.
Exper. 6.—But the moft remarkable inftance of the
penetrability of the elearic light, is that related by
Di Piieftley. “ I laid a chain (fays he), w'hich wras in
contaa wath the outfide of a jar, lightly on my finger,
and. fometimes kept it at a fmall diftance by means of
a.thin piece of glafs. If I made the difcharge at the
diftance of about three inches, the elearic fire wras vi¬
fible on the furface of the finger, giving it a Hidden
concuflion, wdiich feemed to make it vibrate to the very
bone; and wLen it happened to pafs on that fide of the
finger that was oppofite the eye, the whole feemed, in
the dark, perfeaiy tranfparent.”
The following, is Mr Cavallo’s method of making
this curious experiment.
Let the extremities of two wares, one of which pro¬
ceeds from the outfide of a charged jar, and another
from one branch of the difcharging rod, be laid on a
table at the diftance of one-tenth of an inch from each
other j then put the thumb juft upon that interruption
prefling .it flat down. This done, bring the difchargl
ing rod in contaCI with the knob of the jar, and on
making the difcharge, the fpark which neceffarily hap¬
pens under the thumb will illuminate it in fuch a man¬
ner that the bone and the principal blood-veffels may¬
be eafily difcemed in it,
I»
17S>
illuftrated
by experi
ment.
I So
Spiral tube
Chap. VII. ELECT
Principles of In this experiment the operator need not be afraid of
receiving a hiock j for the difeharge of the jar paffes
from wire to wire, and only affe&s the thumb with a
fort of tremor, which is far from being painful.
' We have before related Mr Hawkefbee’s experi¬
ment by which he rendered fealing-wax tranfparent.
Signior Beccaria effe&ed the fame by making an elec¬
tric explolion pafs between two plates of fealing-wax,
on which fome brafs-dult was fprinkled. The whole
was rendered perfectly luminous and tranfparent.
Exper. 7.—Fig. 57. reprefents an inilrument com-
pofed of two glafs tubes CD, one within another, and
clofed with two-knobbed brafs caps A and B. The in-
nermoft of thefe has a fpiral row of fmall round pieces
of tin-foil Ituck upon its outfide furface, and lying at
about one-thirtieth of an inch from each other. If
this inftmment be held by one of the extremities, and
its other extremity be presented to the prime conduftor,
every fpark that it receives from the prime conductor
will caufe fmall fparks to appear between all the round
pieces of tin-foil ftuck upon the innermolt tube 5 which
in the dark affords a plealing fpe&acle, the tube ap¬
pearing encompaffed by a fpiral line of fire.
Fig. 58. reprefents feveral fpiral tubes placed round
a board, in the middle of which is ferewed a glafs pil¬
lar, and on the top of this pillar is cemented a brafs
cap with a fine fteel point. In this a brafs ware turns,
having a brafs ball at each end, nicely ballanced on
the ware. To make ufe of this apparatus, place the
middle of the turning wire under a ball proceeding from
the conductor, fo that it may receive a fucceflion of
fparks from the ball; then pulh the wire gently round;
and the balls in their relative motions will give a fpark
to each tube, and thereby illuminate them down to the
board, which from its brilliancy and rapid motion, af¬
fords a moft beautiful and pleafing fight.
Exper. 8.—The fmall pieces of tin-foil may be ftuck
on a fiat piece of glafs ABCD, fig. jcp. fo as to repre-.
lent various fanciful figures. Upon the fame principle
is the word Light produced, in luminous chara&ers.
It is formed by the fmall feparations of the tin-foil
palled on a piece of glafs fixed in a frame of baked
wood, as reprefented fig. 60. To ufe this, the frame
muft be held m the hand, and the ball G prelented to1
the condu£tor. 1 he Ipark then wull be exhibited in.
the intervals compofing the word ; from whence it
paffes to the hook at h, and thence to the ground by a
chain. The brilliancy of this is equal to that of the
fpiral tubes.
. Though many of the following experiments on elec-
tric light, may not wdth. ftri£t propriety belong to this
chapter, we (hall relate them here for the fake of uni-
xSa formity.
Morgan’5 Mr G. Morgan, in the Philofophical Tran factions for
^eSric5 h?S Slven a.feries of propofitions refipefting the
ight. eleftric light, and illuftrated them by experiments j we
fliall here give the fubftance of his paper nearly in his
own wmrds.
I. There is no fluid or folid body, in its paffage
through which the ele&ric light may not be rendered
luminous.
This propofition has been fully illuftrated by the fore¬
going experiments.
t.83 II. The difficulty of making any quatitity of the elec-
iSt
Luminous
word.
R I C I T Y. 705
trical light vifible in anybody, increafes as the con-Principlesof
dueling power of that body increafes. Electricity
Exper. 1.—In order to make the contents of ajar b^exTerf
luminous in boiling water, a much higher charge is ^ment.
neceffary, than would be fufficient to make it luminous ' ——y— ■*
in cold water, which is univerfally allowed to be the
worft condu£tor.
Exper. 2.—There are various reafons for believing
the acids to be very good conductors j if, therefore,
into a tube filled with water, and circumftanced as has
been already deferibed, a few drops of either of the mi¬
neral acids are poured, it will be almoft impoffible to
make the light vifible in its paffage through the tube.
Exper. 3.—If a ftring, whofe diameter is one-eighth
of an inch, and whofe length is fix or eight inches, is
moiftened with water, the contents of a jar will pafs
through it luminoully 5 but no fuch appearance can be
produced by any charge of the fame jar, provided the
fame ftring be moiftened wuth one of the mineral acids.
To the preceding ‘inftance we may add the various
inftances of metals which will conduft the eleClric
power without any appearance of light, in circum-
ftances the fame with thofe in which the fame force
ivould have appeared luminous in pafling through other
bodies, whofe conducting power is lefs.
III. That the eafe with which the eleCtric light is 184
rendered vifible in any particular body, is increafed by
increafing the rarity of the body. The appearance of
a fpark, or of the difeharge of a Leyden phial, in rare¬
fied air, is well known. But w^e need not reft the
truth of the preceding obfervation on the feveral varie¬
ties of this faCt; fimilar phsenomena attend the rarefac¬
tion of ether, of fpirits of wine, and of water.
Exper. 4.—Into the orifice of a tube, 48 inches
long, and two-thirds of an inch in diameter, cement an
iion ball, fo as to bear the weight which preffes upon it
when the tube is filled with quickfilver, leaving only
an interval at the open end, which contained a few
drops of water. Having inverted the tube, and plun¬
ged the open end of it into a bafon of mercury, the mer¬
cury in the tube Hood nearly half an inch lower than it
did in a barometer at the fame inftant, owing to
the vapour which was formed by the w^ater. But
through this rarefied water, the eleCtrical fpark paffed
as luminoufly as it does through air equally rarefied.
. Exper. 5.—If, inftead of water, a few drops of fpi¬
rits of wine are. placed on the furface of the mercury
phenomena, fimilar to thofe of the preceding experi¬
ment, will be difeoyered, with this difference only, that
as the vapour in this cafe is more denfe, the eleClrical
fpark, in its paffage through it, is not quite fo luminous
as it is in the vapour of water.
Exper. 6.—Good ether, fubftituted in the room of
the fpirits of wine, will prefs the mercury down fo low
as the height of 1.6 or 17 inches. The eledric fpark,
m paffmg through this vapour, (unlefs the force be very
great indeed), is fcarcely luminous ; but if the preffure
on the furface of the mercury in the bafon, be gradual-
y leffened by the aid of an air-pump, the vapour will
become more and more rare, and the eledric fpark, in
palling through it, more and more luminous.
Exper. 7. It has not been difeovered, that any
vapour does efcape from the mineral acids when ex-
pofed in vacuo. To give them, therefore, greater ra¬
rity
704 ELECT
Principltsofnty or tenuity, different methods are found neceffary.
Electricity a fine camel-hair pencil, dipped in the fulphuric,
illuftrattd ^ • J . I
by ex ieri t^ie nltrici or the muriatic acid, draw upon a piece or
ment. glafs a line, about one-eighth of an inch broad. In
1" —y-'-" ■' fome inftances, you muff extend this line to the length
of 27 inches, and you will find that the contents of an
electric battery, confifting of ten pint phials coated,
will pafs over the whole length of this line with the
greateff brilliancy. If, by widening the line, or by
laying on a drop of the acid, its quantity be increafed
in any particular part, the charge, in paffmg through
that part, will not appear luminous. Water, fpirits of
wine, circumffanced fimilarly to the acids in the pre¬
ceding experiments, will be attended with fimilar, but
not equal effedls j becaufe, in confequence of the infe¬
riority of their conducting power, it wall be neceffary
to make the line, through which the charge paffes, con-
fiderably fhorter.
185 IV. The brilliancy or fplendour of the eleftric light,
in its paffage through any body, is always increafed by
leffening the dimenfions of that body j that is, a fpark,
or the difcharge of a battery, which we might fuppofe
equal to a fphere one quarter pf an inch in diameter,
will appear much more brilliant, if the fame quantity is
compreffed into a fphere one-eighth of an inch in dia¬
meter. This obfervation is the obvious confequence cf
many known faffs •, if the machine be large enough to
afford a fpark, whofe length is nine or ten inches, this
fpark may be feen fometimes forming itfelf into a brulh,
in which ftate it occupies more room, but appears very
faintly luminous •, at other times, the fame fpark may
be feen dividing itfelf into a variety of ramifications,
which (hoot into the furrounding air. A fpark, which
in the open air cannot exceed one quarter of an inch in
diameter, will appear to fill the whole of an exhaufted
receiver, four inches wide and eight inches long : but
in the former cafe it is brilliant, and in the latter it
grows fainter and fainter, as the fize of the receiver
increafes. This obfervation is further proved by the
following experiments.
Ex/)cr. 8.—To an infulated ball, four inches in dia¬
meter, fix a filver thread, about four yards long. This
thread, at the end which is remoteft from the ball, muff
be fixed to another infulated fubftance. Bring the ball
within the ffriking diftance of a conductor, and the
fpark, in paffmg from the condu&or to the ball, wall
appear very brilliant; the whole length of the filver
thxead will appear faintly luminous at the fame inftant.
When the fpark is confined within the dimenfions of a
fphere, one-eighth of an inch in diameter, it will be
bright} but when diffufed over the furface of air which
received it from the thread, it’s light will be fo faint as
to be feen only in a dark room. If you leflen the iur-
face of air which receives the fpark, by fhortening the
thread, it will not fail to increafe the brightnefs of the
appearance.
Erfier. 9.—To prove that the faintnefs of the elec¬
tric light in vacuo, depends on the enlarged dimenfions
of the fpace through which it is diffufed ; wTe have no¬
thing more to do than to introduce two pointed wires
into the vacuum, fo that the fluid may pafs from the
point of the one to the point of the other •, when the
diftance between them is not more than the one-tenth
of an inch, in this cafe we fliall find a brilliancy as
great as in the open air.
4
It I C I T Y.
Part III.
1st;
Exper 10.—Into a Torricellian vacuum* 36 inchesP'inciplesof
long, convey as much air as will fill twTo inches only of Ebdlncity
the exhaufted tube if it wTere inverted in water; this j, ^x^teri-
quantity of air will afford refiftance enough to con- ment.
denfe the light as it paffes through the tube into a l——v~--/
fpark, 38 inches in length. The brilliancy of the
fpark in condenfed air, in water, and in all liibftances
through which it paffes with difficulty, depends on prin¬
ciples iimilar to thole which account for the preceding
fads.
V. That in the appearances of ele&ricity, as well as
in thofe of burning bodies, there are cafes in which all
the rays of light do not efcape ; and that the moft re¬
frangible rays are thofe which efcape firft or moft eafily.
'The electrical brulh is always of a purple or bluilh hue.
If you convey a fpark through a Torricellian vacuum,
made without boiling the mercury in the tube, the
brulh will difplay the indigo rays. The fpark, how¬
ever, may be divided and weakened, even in the open
air, fo as to yield the moft refrangible rays only.
Exper. 11.—To an infulated metallic ball, four in¬
ches in diameter, fix a wire a foot and half long j this
wrire Ihould terminate in four ramifications, each of
which mull be fixed to a metallic ball half an inch in
diameter, and placed at an equal diftance from a metal¬
lic plate, which mult be communicated by metallic
conductors with the ground. A powerful fpark, after
falling on the large ball at one extremity of the wire,
will be divided in it’s paffage from the four fmall balls
to the metallic plate. When you examine the divifion
of the fpark in a dark room, you will difeover fome lit¬
tle ramifications, which will yield the indigo rays only s
indeed at the edges of all weak fparks, the fame purple
appearance may be difeovered. You may likewife ob-
ferve^ that the nearer you approach the center of the
fpark, the greater is the brilliancy of its colour.
VI. That the influence of different media on elec¬
trical light, is analogous to their influence on folar
light, and will help us to account for fome very
Angular appearances.
Exper. 12.—Let a pointed wire, having a metal¬
lic ball fixed to one of its extremities, be forced ob¬
liquely into a piece of wood, fo as to make a fmall angle
with the furface of the wood, and to make the point lie
about one-eighth of an inch below the furface. Let an¬
other pointed wire, which communicates with the ground,
be forced in the fame manner into the fame wood, fo
that its point likewife may lie about one-eighth of an
inch below the furface, and about two inches diftant
from the point of the firft wire. Let the wood be infu¬
lated, and a ftrong fpark, which ftrikes on the metallic
ball will force its paffage through the interval of wood
which lies between the points, and appear as red as
blood. To prove that this appearance depends on the
wood’s abforption of all the rays but the red ; when
thefe points were deepeft below the furface, the red on¬
ly came to the eye through a prifm ; when they wrre
raifed a little nearer the furface, the red and orange
appeared 3 when nearer ftill, the yellow 3 and fo on,
till, by making the fpark pafs through the wood very
near its furface, all the rays wTere at length able to reach
the eye. If the points be only One-eighth of an inch
below the furface of foft deal wmod, the red, the o-
range, and the yellow rays will appear as the fpark
paffes through it 3 but whea the points are at an equal
depth
Chap. VII. ELECT
principles of depth in a harder piece of wood, (fuch as box) the yel-
Eledlricity iow> ancJ perhaps the orange will difappear. As a far*
il'uftrated t|ier proof tliat the phenomena, thus defcribed, are
k^rnent ^ owing to t*le interpofition of the wood, as a medium
t ' which abforbs fome of the rays, and fuffers others to
efcape 5 it may be obferved, that when the fpark llrikes
very brilliantly on one fide of the piece of deal, on the
other fide it will appear very red. In like manner,
a red appearance may be given to a fpark which ftrikes
brilliantly over the infide of a tube, merely by Ipread-
ing fome pitch very thinly over the outfide of the fame
tube.
Exper. 13.—If into a Torricellian vacuum, of any
length, a few drops of ether are conveyed, and both
ends of the vacuum are Hopped up with metallic con*
duftors, fo that a fpark may pafs through it; the fpark
in its paffage will affume the following appearances.
When the eye is placed clofe to the tube, the fpark will
appear perfectly white ; if the eye is removed to the
difiance of fix or feven yards, the colour of the fpark
will be reddilh. Thefe changes evidently depend on
the quantity of medium through which the light paffes,
and the red light of a difiant candle, or a beclouded
fun.
Exper. 14.—Dr Prieftley long ago obferved the red
appearance of the fpark when palling through hydrogen
gas ; but this appearance is very much diverfified by
the quantity of medium, through which you look at
the fpark. When at a very confiderable diftance, the
red comes to the eye unmixed j but if the eye is placed
clofe to the tube, the fpark appears white and brilliant.
In confirmation, however, of fome of thefe conclufions,
you muft obferve, that by increafing the quantity of
fparks which are conveyed through any portion of hy¬
drogen gas, or by condenfing that gas, the fpark may
be entirely deprived of its red appearance, and made
perfectly brilliant. All Weak explofions and fparks,
when viewed at a diftance, bear a reddilh hue. Such
are the explofions which have palled through water,
fpirits of wine, or any bad conductor, when confined in
a tube whofe diameter is not more than an inch. 1 he
reafon of thefe appearances feems to be, that the weak¬
er the fpark or explofion is, the lefs is the light which
efcapes •, and the more vifible the effed of any medium,
which has a power to abforb fome of that light.
Chalk, oyfter-lhells, together with thofe. phosphoric
bodies, whole goodnefs has been very much impaired by
long keeping, when finely powdered, and placed within
the circuit of an eledtrical battery ; will exhibit, by
their fcattered particles, a fhower of light} but thefe
particles will appear reddilh, or their phofphoric power
will be fufficient only to detain the yellow, orange, and
red rays. When fpirits of wine are in a fimilar manner
brought within the circuit of a battery, a fimilar effecl
may be difcovered •, its particles diverge in feveral di-
redtions, difplaying a moft beautiful golden appearance.
The metallic oxides are, of all bodies, thofe which are
rendered phofphoric with the greateft difficulty 5 but
even thefe may be fcattered into a Ihower of red lumi¬
nous particles by the eledtric firoke.
Vol. VII. Part II.
It I C I T Y.
1°S
The following experiments are given by Mr Cava no Principles o£
to illuftrate the appearance of the eledtnc light in rare-
lied air. # by expeii-
Exper. 1.—Fig. 61. reprefents a prime condudtor, mPnt.
invented by Mr Henly, which ffiows clearly the di- u-—v~—
redtion of the eledlric poiver palling through it, from
whence it is called the luminous conduSior (4). They^jj"^!,
middle part EF of this condudlor, is a glafs tube about""
eighteen inches long, and three or four inches in dia¬
meter. To both ends of this tube the hollow brafs
pieces FD, BE, are cemented air-tight, one of which
has a point C, by which it receives the eledtric power,
when fet near the excited cylinder of the eledtricair
machine, and the other has a knobbed wire G, from
which a ftrong fpark may be drawn , and from each of
the pieces FD, BE, a knobbed ware proceeds, within
the cavity of the glafs tube. The brafs piece FD, or
BE, is compofed of two parts, i. e. a cap F cemented
to the glafs tube, and having a hole with a valve, by
which the cavity of the glafs tube may be exhaufted of
air $ and the ball D, which is fcrewed upon the cap
F. The fupporters of this inftrument are two glafs
pillars faftened in the bottom board H, like the prime
condudtor reprefented fig. 61. When the glafs tube
of this condudtor is exhaufted of air by means of an
air-pump, and the brafs ball is fcrewed on, as repre¬
fented in the figure, then it is fit for ufe, and may
ferve for a prime condudtor to an eledtrical machine.
If the point C of this condudtor is fet near the ex¬
cited cylinder of the machine, it will appear illuminat¬
ed with a ftar j at the fame time the glafs tube will ap¬
pear all illuminated with a weak light 5 but from the
knobbed wire, that proceeds within the glafs from the
piece FD, a lucid pencil will iffue out, and the oppo-
fite knob will appear illuminated with a ftar or round
body of light, which, as wTell as the pencil of rays, is
very clear, and difcernible among the other light, that
occupies the greateft part of the cavity of the tube.
If the point C, inftead of being prefented to the cy¬
linder, be connedled with the rubber of the machine,
the appearance of light within the tube wdll be rever-
fed ; the knob which communicates writh the piece FD
appearing illuminated wdth a ftar, and the oppofite
wuth a pencil of rays.
If the wires within the tube EF, inftead of being
furnifiied with knobs, be pointed, the appearance of
light is the fame, but it feems not fo ftrong in this, as
in the other cafe. ^
Exper. 2.—Take a glafs tube of about twro inches' ondu&Ing
diameter, and about two feet long ; fix to one of its glafs tube,
ends a brafs cap, and to the other a ftop-cock, or a
valve j then by means of an air-pump exkauft it of air.
If this tube be held by one end, and its other end be
brought near the eleftrified prime conduftor, it will
appear to be full of light, wffienever a fpark is taken
by it from the prime condudlor ; and much more fo,
if an eledtric jar be difcharged through it.
This experiment may alfo be made wuth the receiver
of an air-pump.—Take, for inftance, a tall receiver,
clean and dry, and through a hole at its top infert a
4 U wire,
(a) An inftrument much like this condudlor xvas fome years ago invented by Dr Watfon, with which he made
feveral original experiments upon -the eledtric light.
7<o6
tealis.
Principles ofwire, which muft be cemented air-tight. The end of
Tlluftmed the wire’ that Js within the tube, muft be pointed, but
by experi- n<?t very hiarp j and the other end muft be furnifhed
ment. with a knob. Put this receiver upon the plate of the
v 1 ‘ air-pump, and exhauft it. If now the knob of the
wire at the top of the receiver be touched with the
prime conduclor, every fpark will paO: through the
receiver in a denfe and large body of light, from the
wire to the plate of the air- pump.
It muft be obferved, that when the air is very much
rarefied, the eledric light in it is lefs denfe, though
i5o more diftufedj and contrary-wife.
Aurora bo- Exper. 3.— Take a phial nearly of the fhape and
fize of a Florence ftalk, fuch as is reprefented at fig.
62.
Fix a ftop-cock or a valve to its neck, and exhauft
it of air as much as it is poffible with a good air-pump.
If this glafs be rubbed in the common manner ufed to
excite eledrics, it will appear luminous within, being
full of a flalhing light, which plainly refembles the au¬
rora borealis, or northern light. This phial may alfo
be made luminous by holding it by either end, and
bringing the other end to the prime condudor j in this
cafe all the cavity of the glafs will inftantly appear full
of flalhing light, which remains in it for a conlider-
able time after it has been removed from the prime con¬
dudor.
Inftead of the above-defcribed glafs veffel, a glafs
tube, exhaufted of air and hermetically fealed, may be
ufed, and perhaps with greater advantage. The moft
remarkable circumftance of this experiment is, that if
the phial or tube, after it has been removed from the
prime condudor (and even feveral hours after its Halh-
ing light hath ceafed to appear) be grafped with the
hand, ftrong flafhes of light will immediately appear
within the glafs, which often reach from one of its ends
to the other.
Exper. 4.—GI, fig. 63. reprefents the receiver with
the plate of an air-pump. In the middle of the plate
IF, a Ihort rod is fixed, having at its top a metal ball
H nicely polilhed, whofe diameter is nearly two inches,
from the top of the receiver another rod AD with a
like ball A proceeds, and is cemented air-tight in the
neck C ; the diftance of the balls from one another
being about four inches, or rather more. If, when
the receiver is exhaufted of air, the ball A be eledri-
fied pofitively, by touching the top D of the rod AD
with the prime condudor or an excited glafs tube, a
lucid atmofphere appears about it, which, although it
confifts of a feeble light, is yet very confpicuous, and
very well defined j at the fame time the ball B has not
the leaft light. The atmofphere does not exift all
round the ball A, but reaches from about the middle
of it, to a fmall diftance beyond that fide of its furface,
which is towards the oppofite ball B. If the rod with
the ball A be eledrified negatively, then a lucid at¬
mofphere, like the above defcribed, will appear upon
the ball B, reaching from its middle to a fmall diftance
beyond that fide of it, that is towards the ball A j
at the fame time the negatively eledrified ball A re¬
mains without any light.
The operator in this experiment muft take care not
to eledrify the ball A too much, as, in that cafe, a
fpark will pafs from one b’.ll to the other, and the de-
fired effed will not be produced. A little pradice.
ELECTRICIT Y.
Part III.
I<)t
Vilible e-
ledric at-
mofphere.
192
however, will render the experiment very eafy and fa-Principles of
miliar. Ele&ricity
This elegant experiment is the invention of Sig. Bee- 'llufl;rate.c*
caria. J expen-
t?- zr 1 r • ment.
rig. 64. and 65. reprefent a curious appearance of <
the eledric light. In fig. 65. the light is feen ftream-
ing from a wire within the exhaufted receiver of an air-
pump. If in this ftate of things, the hand or a finger
be applied to the external part of the receiver, part of
the light will approach the finger, as reprefented in
fig. 64.
l]ie ele&nc fpark produces changes on mojl artificial
colours. T93
Mr Cavallo made feveral experiments on fubftances Mr Caval-
painted with various colours. They were occafioned Io’s exPei i-
by his having obferved that an eledric fpark fent over “^‘srs°n
the furface of a card, made a black ftroke upon a red U S*
fpot, from which he was induced to try the effed of
fending fhocks over cards painted with different w7ater
colours. The force employed was generally about one
foot and a half of charged furface ; and the Ihocks
were fent over the cards while the latter were in a
very dryjlate.
“ Vermilion was marked wfith a ftrong black track,
about one tenth of an inch wide. This ftroke is ge¬
nerally fingle, as reprefented by AB, fig. 66. Some¬
times it is divided in twro towards the middle, like
EF j and fometimes, particularly wFen the wires are
fet very diftant from one another, the ftroke is not
continued, but interrupted in the middle, like GH.
It often, although not always happens, that the im-
preftion is marked ftronger at the extremity of that
wire from which the eledric fparks iffue, as it appears
at E, fuppofing that the wire C communicates w ith the
pofitive fide of the jar ; wdiereas, the extremity of the
ftroke, contiguous to the point of the wire D, is nei¬
ther fo ftrongly marked, nor furrounds the wire fo
much, as the other extremity E.
“ Carmine received a faint and {lender impreflion of
a purple colour.
“ Verdegrife was ftiaken off from the furface of the
card y except when it had been mixed wfith ftrong
gum-water, in which cafe it received a very faint im¬
preflion.
“ White lead was marked by a long black track,
not fo broad as that on vermilion.
“ Red lead was marked with a faint mark much like
carmine.
The other colours I tried wTere orpiment, gamboge,,
fap green, red ink, ultramarne, pruffian blue, and a
few others which were compounds of the above •, but
they received no impreflion.
“ It having been infinuated, that the ftrong black
mark, which vermilion receives from the eledric ftiock,
might poflibly be owing to the great quantity of ful-
phur contained in that mineral, I was induced to make
the following experiment. I mixed together equal
quantities of orpiment and flowrer of fulphur •, and with
this mixture, by the help, as ufual, of very diluted gum-
wrater, I painted a card ; but the eledric ftiock fent
over it left not the leaft impreflion.
“ Defirous of carrying this inveftigation on colours
a little farther, with a particular view to determine
fomething relative to the properties of lamp black and
oil, I procured fome pieces of paper painted on both
fides
 r VIII. ELECT
Piinciples of Tides with oil colours •, and fending the charge of two
Chap.
R I C I T Y.
707
iiuca y     O — . ,
Electricity £eet 0£ COated glafs over each of them, by mahing the
illuftrated ;nte tion 0£ the circuit upon their furfaces, I obferv-
h^mentri" ed that the pieces of paper painted with lamp black,
1—„'-L; pruffian blue, vermilion, and purple brown, were torn
by the explofion j but white lead, Naples yellow, .Lng-
liih ochre, and verdigrife, remained unhurt.
“ The fame fhock lent over a piece of paper paint¬
ed very thickly with lamp black and oil left not the
leaft impreffion. I fent the (hock alfo over a piece of
paper unequally painted with purple browri, and the
paper was torn where the paint lay very thin, but re¬
mained unhurt where the paint lay evidently thicker.
Thefe experiments I repeated feveral times, and with
fome very little variation, which naturally produced
different effeas •, however, they all feem to point out
the following propofitions.
“ 1. A coat of oil-paint over any fubftance, defends
it from the effecf of fuch a fhock as would otherwise
injure it } but by no means defends it from any elcclnc
fhock whatever.
“ 2. No one colour feems preferable to the others, if
they are equal in fubftance, and equally well mixed
with oil; but a thick coating does certainly afford a
better defence than a thinner one.
“ By rubbing the above mentioned pieces of paper,
I find that the paper painted with lamp-black and oil
is more eafily excited, and acquires a ftronger eleftri-
citv, than the papers painted with the other colours }
and perhaps on this account it may be, that lamp black
and oil might refift the fhock fomewhat better than the
other paints. . 1111
“ It is remarkable that vermilion receives the black
impreflion when painted with linfeed oil nearly as well
as when painted with water. The paper painted with
white lead and oil receives alfo a black mark} but its na¬
ture is very fmgular. The track when firft made, is al-
moft as dark as that marked on white lead painted with
Water *, but it lofes its blacknefs, and in about an hour’s
time (or longer, if the paint is not frefh) it appears
without any darknefs ; and when the- painted paper, is
laid in a proper light appears only marked with
a colourlefs track, as if made by a finger nail. I fent
the {hock alfo over a piece of board, which had been
painted with white lead and oil four years before, and
the explofion marked the black track upon this alio;
this track, however, wras not fo ftrong, nor vanifhed
fo foon, as that marked upon the painted paper j but in
about twro days time it alio vanifhed entirely.
Chap. VIII. Of/fo Mechanical Effects of the Electric
Power.'
The eleBric power in its pajfage through the air,
ls, drives light bodies before it.
Electnc Sig. Beccaria put a narrow piece of filver leaf be-
power tween tw*o plates of wax, laying it acrofs them, but fo
drives light}p0 tpat jt ^id not quite reach one of the fides. The
'bodies be- dJfc]large being made through this ftrip of metal, by
bringing a wTire oppofite to the filver at the place where it
was difcontinued ; the filver was found melted, and
part of it difperfed all along the track that the eledlric
fpark took betw een the plates of w'ax, from the filver
to the wire.
The following experiment fliows the force of the elec*
trie explofion in driving the particles of a metal into the WnaplescT
Eledlricity
iiluftrated
pores of glafs. . r , miurraicu
Take two flips of common window glafs, about three eXpen_
inches long, and half an inch wdde } put a fmall flip ment.
of gold, filver, or brafs leaf, between them, and tie -
them together, or prefs them together between the
boards of the prefs H, belonging to the univerfal dif-
charger, leaving a little of the metallic leaf out between
the glaffes at each end ; then fend a fhock through this
metallic leaf, and the force of the explofion will drive
part of the metal into fo clofe a contacl with the glafs,
that it cannot be wiped off, or even be affected by the
common menftrua which otherwife would difiblve it.
In this experiment the glafies are often fhattered to
pieces j but whether they are broken or not, the inde¬
lible metallic tinge wall always be found in feveral
places, and fometimes through the whole length of both
glaffes.
Dr Prieftley made the following experiments to aft
certain this remarkable property of the eledfric power.
He difeharged frequent fhocks both of a common
jar, and another of three fquare feet, through trains.of
brafs duft, laid on a ftool of baked wTood, making in¬
terruptions in various parts of the train j and he al¬
ways found the brafs duft fcattered in the intervals, fo
as to connedl the two disjoined ends of the train j but
then it w'as likewife fcattered nearly as much from aft
moft all other parts of the train, and in all direc¬
tions.
When fmall trains were laid, the difperfion was the
moft confiderable, and a light w*as very viiible in the
dark, illuminating the wdrole circuit. It made no dif¬
ference, in any of thefe experiments, which way the
{hock was difeharged.
When he laid a confiderable quantity of the duft at
the ends of twro pieces of chain, through which the
fhock paffed, at the diftance of about three inches from
one another, the duft was always difperfed over the
whole interval, but chiefly laterally 5 fo that the great-
eft quantity of it lay in arches, extending both ways,
and leaving very little of it in the middle of the
path. '
The Doctor then infulated a jar of three fquare feet,
and upon an adjoining glafs Hand laid a heap of brais
duft ; and at the diftance of feven or eight inches, a
brafs rod communicating with the outfide of the jar.
Upon bringing another rod communicating with the
infide, upon the heap of duft, the heap was difperfed
ia a beautiful manner, but not one way more than the
other. It however, prefently reached the rod com¬
municating with the outfide-.
Making two heaps, about eight inches afunder, he
brought one rod communicating with the infide upon
one of them, and another rod communicating with the
outfide upon the other. Both the heaps were difperfed
in all direfrions, and foon met; prefently after which
the jar was difeharged by means of this difperfed duft,
in one full explofion. When the two heaps were too
far afunder to promote a full difeharge at once, a gra¬
dual difeharge was made through the fcattered particles
of the duft.
When one heap of duft was laid in the centre of the
ftand, and the two rods were made to approach on each
fide of it, they each attrafted the duft from the fide of
the heap next to them, and repelled it again in all di-
4 U 2 regions.
ment.
19S
708 E L £ C T R
ErLt£f??[0nS- ‘%came very nor the heap, the
iltuftrateit dl,cl.lalge was made through it, without giving it any
by expcri- Partlcular motion.
An experiment given by Mr Cavallo to prove the
— diredhon of the_ elearic power in the difcharge of a
Leyden phial, will afford a good illuftration of our pre-
lent pofition. r
Bend a card, length-ways, over a round ruler, fo as
to form a channel, or femicircular groove (s) : lay
this card upon the circular board E of the univerfal
difcharger, and in the middle of it put a pith-ball of
about half an inch diameter ; then at equal diflances,
about half or three quarters of an inch from the pith-
ball, lay the two brafs knobs EE. Lhe card being
perfeftly dry, and rather hot, if you connedl, by means
of a chain or otherwife, the outfide of a charged jar
with one of the wires C, and bring the knob of the jar
to the other wire C, you will obferve, that on making
the difcharge, which muff pafs between the knobs EE,
and over the card, &c. the pith-ball is always driven
m the direftion of the dearie power ; i. e. it is puflied
towards that knob which communicates with the nega¬
tive fide of the jar.
It muff be obferved, that in this experiment the
charge of the jar muff be juft fufficient to pafs through
the interval in the circuit } the card, or piece of baked
wood, muft be very dry and clean j and, in fhort, the
difpofition of the apparatus, and the performance of
this curious experiment, require a degree of nicety that
can only be obtained by praaice. Without great pre¬
caution, it fometimes fails j but when the operator has
once got it to fucceed, and follows exadtly the fame
method of operating, he may be fure that the event of
the experiment will be conftantly as above deferib-
ed.
By the electric explofion, paper, pajlehoard, card, thin
glafs, and other non-conduBitig fubjlances, tnay be perfor¬
ated or broken.
Exper. 1.—Take a card, a quire of paper, or the
cover of a book, and keep it clofe to the outfide coat¬
ing of a charged jar 5 put one knob of the difeharging
rod upon the card, quire of paper, &c. fo that between
the knob and coating of the jar the thicknefs of that
card or quire of paper only is interpofed ; laftly, by
bringing the other knob of the difeharging rod near
the knob of the jar, make the difcharge, and the elec¬
tric fpark will pierce a hole (or perhaps feveral) quite
through the card or quire of paper. This hole has a
bur raifed on each fide, except the card, &c. be preffed
hard between the difeharging rod and the jar. If this
experiment be made with two cards inftead of one,
which however muft be kept very little diftant from
one another, each of the cards, after the explofion, will
be found pierced with one or more holes, and each hole
will have burs on both furfaces of each card. The
hole, or holes, are larger or fmaller, according as the
card, &c. is more damp or more dry. It is remark¬
able, that if the noftrils are prefented to it, they will
1 c IT Y. Fart III.
be affedted with a fulphureous, or rather a phofpho-Principles of
196
real imell, juft like that produced by an excited elec- Electricity
trie. illuftrated
If, inftead of paper, a very thin plate of glafs, rofin, byn^®ri'
fealing wax, or the like, be interpofed between the-y—L-i
knob of the difeharging rod and the outfide coating
of the jar, on making the difcharge, this will be bro¬
ken in ieveral pieces.
^ If the explofion is fent over the furface of a piece of
glafs, this will be marked with an indelible track,
I' hich generally reaches from the extremity of one of
the wires to the extremity of the other. In this man¬
ner, the piece of glafs is very feldom broken by the
explofion. But Mr Henley difeovered a very remark¬
able method to increafe the efFed of the explofion upon
the glafs ; which is by prefling with weights that part
of the glafs which lies between the two wires (i. e. that
part over which the fhock is to pafs). He put firft a
thick piece of ivory upon the glafs, and placed upon
that ivory a weight at pleafure, from one quarter of an
ounce to fix pounds : the glafs in this manner is gener¬
ally broken by the explofion into innumerable frag¬
ments, and lome of it is abfolutely reduced into
an impalpable powder. If the glafs is very thick,
and refills the force of the explofion, fo as not to be
broken by it, it will be found marked with the moft
lively prifmatic colours, which are thought to be oc-
cafioned by very thin laminae of the glafs, in part fe-
parated from it by the Ihock. The weight laid upon
the glafs is always fliook by the explofion, and fome¬
times it is thrown quite off from the ivory. This ex¬
periment may be moft conveniently made with the uni¬
verfal difcharger.
Exper. 2.—Place the extremities of two wires, one
above and the other below a card, fo as to be about an
inch diftance from each other, taking care that the ,
card be kept fteady. Then, make the charge of a
Leyden phial pafs from one wire to the other, and it
will be found, that a luminous track will pafs from the
end of that wire which is connefted with the pofitive
furface of the phial, to the extremity of the other
wire, where a hole will be perforated through the
card.
This experiment, to which we fliall have occafion
to refer hereafter, is by Mr Lullin of Geneva.
Mr Symmer made fome experiments on the perfora¬
tion of paper, which we fhall mention here, as on them
he grounded a principal argument in favour of that
theory which he adopted, and of which we fhall give
an account hereafter.
Exper. 3.—A piece of paper covered on one fide
with Eutch gilding, and which had been left acciden¬
tally between two leaves in a quire of paper, in which
a former experiment had been made, was found to have
the impreflion of two ftrokes upon it, about a quarter
of an inch from each other j the gilding was ftripped
off, and the paper left bare for a little fpace in both
places. In the centre of one of thefe places was a lit¬
tle
(r) Inftead of the card, a piece of baked wood may be cut in that fhape, and painted over with lamp-black
moifture W ^ ^ anfwer better than thc card> * being much more fteady, and not fo liable to attraft
Chap. VIII.
ELECT
Principles oftle round hole, in the other only an indenture or im-
^lu ft rat111 Prei®on> ^uc'1 as might have been made with the point
byUexrpaeri-oft.bodkin- , . „ ,
ment. Exper. 4.—In the middle or a paper book, of the
V—thicknefs of a quire, Mr Symmer put a flip of tinfoil ;
and in another of the fame thicknefs, he put two flips
of the fame fort of foil, including the two middle leaves
of the book between them. ^On palling the explofion
through the two different books, the following elTecls
were produced. In the firft, the leaves on each fide
of the tinfoil were pierced, while the foil itfelf remain¬
ed unpierced 5 but at the lame time, it might be per¬
ceived that an impreffion had been made on each of its
lurfaces, at a little diftance from one another 5 and
fuch impreffions were ftill more vifible on the paper,
and might be traced, as pointing different wrays. In
the fecond, all the leaves of the book wrere pierced,
excepting the two that wTere included between the
flips of tinfoil 5 and in thefe two, inftead of holes, the
two impreffions in contrary dire&ions, were vilible.
The following experiment ffiows how eafily fo hard a
fubftance as glafs, may be pierced by the eledlric fpark.
It is thus related by Mr Cavallo.
Exper. 5.—Let a glafs tube of any diameter, and
about five or fix inches in length, be clofed hermetical¬
ly, or by means of fealing-wax, at one end, and fill
about half of it with olive oil j then flop the aperture
of it with a cork, and let a wire pafs through the
cork, and come fo far within the tube, as to have its
extremity below the furface of the oil. This end of
of the ware mull touch the furface of the glafs, for
wffiich purpofe it mull be bent nearly at right angles,
which may be eafily done before the cork is put upon
the tube. Things being thus prepared, bend into a ring
the other extremity of the wii\ and fufpend it, with
the tube hanging to it, to the wire at the end of the
conduftor. Then work the machine, and bring the
knuckle of a finger or the knob of a wire near the out-
fide of the tube, juft oppofite to the extremity of the
ware ; the confequence of which will be, that a fpark
will happen between the ware and the knuckle, which
makes a hole through the glafs.—By turning the ware
about, or raifing and lowering it, many holes may be
fucceffively made in the fame tube, after the manner
above defcribed.
Exper. 6.—Roll up a piece of foft tobacco-pipe clay
in a fmall cylinder, and infert in it two wires, fo that
their ends without the clay may be about a fifth part of
an inch from one another. If a ffiock be fent through
this clay, by connefting one of the wares wath the out-
fide of a charged jar, and the other with the infide, it
wall be inflated by the fliock, i. e. by the fpark, that
paffes between the two wires, and, after the explofion,
will appear fwelled in the middle. If the Ihock fent
through it is too ftrong, and the clay not very moift, it
wall be broken by the explofion, and its fragments fcat-
tered in every direflion. To make this experiment wath
a little variation, take fa piece of the tube of a tobac¬
co-pipe, about one inch long, and fill its bore with
moift clay 5 then infert in it two wires, as in the above
rolled clay •, and fend a fliock through it. This tube
will not fail to burft by the force of the explofion, and
its fragments wall be fcattered about to a great diftance.
If, inftead of clay, the above-mentioned tube of the
tobacco pipe, or a glafs tube (which will anfwer as
R 1 C l T Y.
709
well), be filled with any other fubftance, either eleftric Principles of
or non-eleftric, inferior to metal, on making- the dif- Electricity
     • ’ 6 - - illuft rated
charge, it wall be broken in pieces with nearly the
fame We TW ,-o  c ti/t- by exPen-
fame force. This experiment is the invention of Mr
Lane, F. R. S.
Exper. 7.— Place within a common drinking-glafs,
nearly full of water, two knobbed wires, bent in fuch a
manner, as that their knobs may be within a little
diftance of each other in the wrater. Conned one of
thefe wares with the outfide coating of a pretty large
jar, and touch the other wire wath the knob of it; on
making the difcharge, the explofion wffiich muft pafs
through the water between the two knobs, will difperfe
the water, and break the glafs with a fufprifing viorf
lence. This experiment requires great caution.
Sig. Beccaria contrived a fmall mortar, into which a
drop of water was put, between the extremities of two
wires which went through the lides of the mortar, and
a wooden ball was applied over the drop "of waiter j
then a charged jar being difcharged through the wires
of the mortar, and confequently through the drop of
water, rarefied the latter, and drove the ball out wath
confiderable force. Mr Lullin produced a greater
effedt by making the difcharge through oil inftead of
wrater.
ment.
Chap. IX. Of the Methods of efimating the De*
gree of Accumulated Electricity in Jars and Bat¬
teries.
The only method of afcertaining the charge of a 197
Leyden phial or of a battery, which wre have hitherto
mentioned, is that of obferving the repulfive force of
the charge _ on the ball of Henly’s quadrant eledrome-
ter. But it wTas found {Viae 122) that this was not
always a juft criterion of the amount of the charge ;
as, even when the jar w'as infulated, and confequently
could receive no charge, the index of the elettrometer
ftill rofe as high as if the jar wois fully charged. We
ffiall now proceed to defcribe two methods, wffiich, par¬
ticularly the laft, are much lefs liable to error. The
firft depends on the following principle.
The di/lance of the ball of a difcbarging rod from the 19 Sv
It nob of a charged phial or battery neceffary to produce
an explofon, will be greater in proportion to the degree
of accumulated electricity which the jar or battery has
received.
Exper.—Take a Leyden phial, into the knob of
which is fixed a quadrant eleftrometer; communicate
to it a fmall charge, fo that the index of the eledrome-
ter may point, wre Ihall fuppofe, at io°. In making
the dilcharge, it wall be found neceflary to bring the
ball of the difcharging rod almoft in contadl with the
knob of the jar. Now charge the jar to 20°, and it
will be found that the explofion will take place, when
the ball of the difcharging rod is at a greater diftance
from the knob of the jar, than before 5 and thus, by
repeating the experiment with greater charges, it wall .'~-%
be obferved,. that the diftance neceffary to produce an
explofion wall increafe nearly in proportion to the
charge. ~
On this principle Mr Lane conftrufted an eleftro-r 1
meter, which has been found extremely ufeful, wffien trometer!'**
it was required to difcharge a jar or battery a number
of times fucceffively, with the fame charge. This in-
ftrument
ELECTRICITY. Fart IlL
Principles'of ftrument has been called Mr Lane’s difcharging elec-
Electricity trometer.
byUexperi d he principal part of it confided originally of a brafs
ment. ball about an inch and a half in diameter, fcrewed to a
f‘..v—graduated brafs rod, and adapted to a proper frame, fo
that it might be fet at any required didance from the
prime conductor of the knob of a Leyden phial. The
chief ufe of this indrument is to allow ajar to difcharge
fpontaneoudy through any proper circuit, without em¬
ploying a difcharging rod, or moving any part of the
apparatus, and alfo to produce fuccedive explodons
nearly of the fame drength, as obferved above. If, for
example, the brafs ball be placed at the didance of
about half an inch from the prime conductor, and a
Leyden phial be fo fituated as to have its knob in con¬
tact with the prime conducdor, while its outdde coat¬
ing communicates with the ball of the electrometer, it
is evident that the communication between the outdde
and indde of the jar, is interrupted only between the
prime conductor and the brafs ball, which are half an
inch afunder •, therefore, in charging the jar, when the
charge is become fo high as to drike through half an
inch of air, the jar will difcharge fpontaneoudy, and by
keeping the brafs ball at the fame didance from the
prime conductor, and charging the jar fucceffively, the
diocks will be nearly of the fame drength.
An electrometer of this kind, though not exactly like
the original one, is now commonly ufed by the prac¬
titioners of medical electricity, and is delineated in
CLXXXIX fig* °f Plate CLXXXIX^ F conMs .of a glafs
' J • arm which proceeds from the wire of the jar F, and
to the extremity E of which a fpring focket is cement¬
ed, through which a wire paffes, which is furnidied
with a knob B, towards the knob A of the jar, and
with an open ring C at its other extremity. Now* as
this wire may be did backwards and forwards, the knob B
may be put at any required didance from the knob A, as
far as the condru&ion of the indrument will allow.
The wire BC is generally marked with divifions which
Ihew the didance of the two knobs, when the wire is
fo fituated, as that the required divifion coincides with
the edge of the fpring focket j as, for indance, one-
tenth, or one quarter of an inch, &c. When the jar
F is fet againd the prime conduftor G, as reprefented
in the figure, fuppofe that the ball B is fet at the
didance of one-tenth of an inch from the ball A, and
that a wire be fixed from the electrometer’s ring to the
outfide coating of the jar, as diewn by the dotted line
CK ; then, when the machine is put in motion, the
difcharge of the jar, as foon as this becomes fudiciently
charged, will be made between the knobs AB, and
through the wire CK ; and it is evident that thefe dif-
charges will be of the fame drength, as long as the di¬
dance between AB remains the fame.
This indrument is fubjecl to the following inconve¬
nience, viz. that the force of the explofion, after a time,
roughens the furface of the brafs ball, and thus, for a
reafon to be explained hereafter, the indrument is ufe-
lefs, unleis the polidi of the ball be again renewed. It
is alfo found that this indrument is not accurate in
diewing the exact charge of a jar.
,£co The charge of a jar or battery may be moj} accurate¬
ly determined by the weight which t/ie repulfvefoicc of
the accumulated electricity is able to raife.
Upon this principle Mr Brooke of Norwich conftrutt-
2
ed a very valuable electrometer, of which he has given Principles of
a long and accurate account in his Mifcellaneous Expe-
litnents, _ by experi-
Our limits will not permit us to copy this long de- ment.
fcription, for which we mud therefore refer our readers  
to Mr Brooke’s work. We have, however, the lefs
reafon to regret this omidlon, becaufe we diall prefent-
ly defcribe an indrument-invented by the late Profeffor
Robifon, which appears to us fuperior to Mr Brooke’s
both in fimplicity and utility.
Mr G. Adams has defcribed an electrometer very
fimilar in principle to that of Mr Brooke, and we diall
here copy his defcription. 2oi
“ Fig. 68. and 69. reprefent an electrometer, near-Eledtrome-
ly fimilar to that contrived by Mr Brooke. The two ter^lnnilar
indruments are fometimes combined in one, or ufed fe- Poke’s,
parately, as in thefe figures. The arms FH/£, fig. 69.
when in ufe, are to be placed as much as podible out
of the atmofphere of a jar, battery, prime conductor,
&c. The arm FFI and the ball K are made of cop¬
per, and as light as podible. The divifions on the arm
FH are each of them exattly a grain. They are af-
certained at fird by placing grain weights on a brafs
ball which is within the ball L, (this ball is an exact
counterbalance to the arm FH and the ball K when
the fmall dide r is at the fird divifion) and then re¬
moving the hide r, till it, together with the ball K,
counterbalances the ball L and the weight laid on it.
A, fig. 69, is a dial-plate, divided into 90 equal
parts. The index of this plate is carried once round,
when the arm BC has moved through 90 degrees, 01'
a quarter of a circle. That motion is given to the in¬
dex by the repulfive powder of the charge afting between
the ball I) and the ball, B.
The arm BC being repelled, {hews wdren the charge
is increafing, and the arm FH (hews what this repulfive
porver is between two balls of this fize in grains, ac¬
cording to the number the weight reds at when lifted
up by the repulfive power of the charge : at the fame
time the arm BC points out the number of degrees to
w hich the ball B is repelled j fo that by repeated trials,
the number of degrees anfwering to a given number of
grains, may be afcertained, and a table formed from
thefe experiments, by which means the ele&rometer,
fig. 69. may be ufed without that of fig. 68.
Mr Brooke thinks that no glafs, charged (as we call
it) with electricity, will bear a greater force, than that
whofe repulfive power, between two balls of the fize he
ufed, is equal to fixty grains ; that in very few indances
it will dand fixty grains weight; and he thinks it ha¬
zardous to go more than 45 grains.
Hence, by knowing the quantity of coated furface,
and the diameter of the balls, we may be enabled to fay,
fo much coated furface, with a repulfion between balls
of fo many grains, will melt a wire of fuch a fize, or
kill fuch an animal, &c.
Mr Brooke thinks, that he is not acquainted with all
the advantages of his eleftrometer j but that it is
clear, it fpeaks a language which may be univerfally
underdood, which no other will do } for though other
ele&rometers will diew whether a charge is greater or
lefs, by an index being repelled to greater or fmaller
didances, or by the charge exploding at different di¬
dances, yet the power of the charge is by no means
afcertained ; but this ele&rometer Ihew's the force of
Chap. IX. ELECT
Principles ofthe repuliive power in grains 5 and the accuracy of the
“1^rument eardy proved, by placing the weights on
by expen- t^e interna^ ball, and feeing that they coincide with
y expen- . 7 o j ■ • —
ment. t^le divifions on the arm FH, when the Hide is removed
> to them.
With his electrometer, Mr Brooke made a fet of ex¬
periments, with a view to determine exactly the force
of batteries of an inferior power, in melting fine metal¬
lic wires of different kinds. The following is the fub-
on the force ftance of thefe experiments.
of batteries. j. a battery of nine bottles, containing about
16 fquare feet of coated furface, and charged to 32
grains of repulfion, a Ihock was eleven times fent
through a piece of iteel wire twelve inches long and
-r^oth of an inch thick ; the wire was fhortened an
inch and a half, being then about ten inches and a
half long j by a twelfth fliock, the wire was melted to
pieces.
2. A (hock from the fame nine bottles charged to
the fame degree of repulfion, being fent through a
piece of fteel wire, 1 2 inches long and tto^ °f an
inch thick, the firft time melted the whole of it into
fmall globules.
3. A fhock from the fame nine bottles charged to
. the fame degree, being fent through a piece of brafs
wire twelve inches long and T4oth of an inch thick,
melted the whole of it, with much fmoke, refembling
that from gunpowder ; but the metallic part formed it-
felf, in cooling, chiefly into concave hemifpherical
figures of various fixes.
4. A fliock from only eight of the bottles charged to
the fame degree, did but juft melt twelve inches of fteel
wfire x4oth of an inch thick, fo as to fall into feveral
pieces 5 thefe pieces in cooling formed themfelves into
oblong lumps, joining themfelves to each other by a
very fmall part of the wire between each lump which
was not melted enough to feparate, but appeared like
oblong beads on a thread at different diftances.
5. A fliock from the fame eight bottles, charged to
the fame degree, fo perfectly heated twelve inches of
brafs wire about x4oth of an inch in diameter, as to
melt it, or at leaft foften it fo far as to make it fall
down by its own weight, from the forceps by which it
was held at each end, upon a ftieet of paper placed be¬
low to catch it, and when it fell down it was fo per-
fe&ly flexible that, by falling it formed itfelf into a ver¬
micular fliape, and remained entire its whole length,
which when it was put into the forceps was about
x 2 inches : but after the ftiock was paffed through it,
it fagged fo much as to be ftretched by its own weight
to almoft fifteen inches, and by falling on the paper it
was flattened throughout its whole length fo much, that
when it was examined by a magnifier of half an inch
focus, it appeared five or fix times as broad as it was
thick.
6. A fliock from nine bottles charged only twenty
grains, was fent through a piece of fteel wire, of the
fame length and diameter as in the former experiments,
and heated it fufticiently to melt it, fo that it feparated
in leveral places j and the pieces were formed into
beads ftrung as in experiment 4.
7. A ftiock from the fame nine bottles charged to
twenty grains was fent through ten inches of brafs wire
TTo'th of an inch diameter j the wire was heated red
hot fo- as to render it very flexible, but it did not fepa-
R I C I T Y. 711
rate. It was fliortened, however, nearly three-eighths Principles of
of an inch. Electricity
8. A fliock from the fame nine bottles charged to
the fame degree, being fent a fecond time through the ment.
laft piece of wire, melted it afunder in feveral places. <■ v — .J
9. A fliock from nine bottles charged to 30 grains,
fent through twelve inches of brafs wire T4gth of an
inch in diameter, afted on it nearly as in experiment 9,
except that it was feparated in two places, and the
pieces when joined meafured about fixteen inches and a
half long j it was perfectly flattened by its fall on the
paper as before.
10. A ftiock from nine bottles charged to 30 grains,
being fent through eight inches and a half of brafs
wire of the fame diameter, wholly difperfed it in fmoke,
and left nothing remaining to fall on the ftieet of paper
placed below it.
11. A ftiock from twelve bottles charged to 20
grains fent through ten inches of fteel wire, -r^o^h of
an inch in diameter, made it red hot, but did not melt
it.
12. A fecond charge, the fame as the laft, being
fent through the fame piece of wire, heated it red hot
as before, but did not caufe it to feparate; the wire
was now, however, ftiortened five-fixteenths of an inch..
13. A ftiock from the fame twelve bottles charged
to. 25 grains, being fent through the fame piece of
wire, partly melted it into feveral pieces, and produced
many globules of oxidated metal.
14. With 15 bottles charged to 25 grains, a ftiock
was fent through ten inches of fteel wire T~th of an
inch in diameter, which melted it at the firft time, and
difperfed a great part of it about the room.
15. A ftiock from the fame 15 bottles charged to
20 grains, juft melted ten inches of fteel wire of the
fame diameter as before, fo as to caufe it to run into
feveral beautiful globules, nearly as in experiment 13.
16. A ftiock of 13 bottles charged to 15 grains, be¬
ing fent through ten inches of fteel wire of the fame
diameter as the laft, made the wire barely red-hot j but
fliortened it one-tenth of an inch.
17. The laft piece of wire having received a ftiock
from 15 bottles charged to 12 and a half grains, was
not made red-hot.
18. A ftiock from the fame 15 bottles, charged to
25 grains, was fent through the fame piece of wire,
and feemingly tore the wire into fplinters.
19.. Four bottles charged to 30 grains, juft melted
three inches of fteel wire -r^oth of an inch in diameter,
fo as to make it fall into pieces.
20. Five bottles charged to 25 grains, melted three
inches of fuch wire as the laft into large beautiful glo¬
bules.
21. With eight bottles charged to 15 grains, three
inches of fteel wire, -r^h of an inch in diameter, were
melted as in the laft experiment j indeed the appear¬
ance and effedl were fo nearly alike in both cafes, that
the metal after both experiments might have been faid
to be the fame.
The force of ten bottles charged twelve grains
22.
and a half rather exceeded experiment 19, but fcarcely
came up to experiments 20 and 21.
23. Sufpedfiing fomething wrong in experiment 19,
Mr Brooke found, that though his bottles hitherto
were as nearly of the fame fixe as he could procure
them.
712 E L E C T K
Principles of them, yet Tome of them were a little larger than others,
Electricity an(j} which was the cafe in experiment 19, one of the
by^xperi* ^our was fnlaher than the other three ; fo that he re-
ment. peated the experiment with four bottles more equal in
v—*—' hze, charging them to 30 grains, and the fulion was as
perfect: as in any.
24. A charge to 30 grains, with the laft eight bot¬
tles, beautifully melted fix inches of fteel wire
an inch in diameter.
25. A fiiock from two bottles charged to 45 grains,
was lent through one inch of It eel wire, of the fame dia¬
meter as the lall, but only changed its colour.
26. With three bottles charged to 40 grains, a {hock
fent through one inch and a half of fteel r^ire of the
above diameter, difperfed it all about the room.
27. Mr Brooke confidering that a fteel wire of T-~th
-of an inch in diameter, contains nearly twice the quan¬
tity of metal which is contained in the fame length of
wire of of an inch in diameter, took three inches
of the former, and fent through it a Ihock from ten
bottles, charged to 25 grains. This Ihock melted it
juft as the Ihock from five bottles did in experiment 2o.
28. With 20 bottles charged to 12 grains and a
half, he melted three inches of fteel wire of -r^oth of
an inch in diameter, exaflly as in the foregoing experi¬
ment.
29. Asa fteel wire of -/oth of an inch diameter con¬
tains nearly twice the quantity of metal iti the fame
length, as is contained in a fteel wire of T~th, or four
times the quantity contained in a fteel wire of TTo^h
of an -inch diameter; it might from the foregoing ex¬
periments be expefted, that 20 bottles charged to 25
grains wTould melt three inches of fteel wrire of -g^h of
an inch in diameter : but on a great many trials he
could not procure 20 bottles which would bear the
difeharge when charged to 25 grains ; for at the dif-
charge, there was always one or more bottles broken
or perforated. He was now reduced to the neceflity of
being content with bottles of any fize, that would bear
the required charge of from one to three gallons each,
or that contained from 150 to 300 or more fquare
inches of coated furface each, but all in vain. The
only refource left him, as he was not near a glafshoufe,
was to increafe the quantity of furface and not to
charge fo high and to proportion the one to the other :
it was therefore refolved to adopt a third expedient, i. e.
inftead of employing about 36 fquare feet of coating,
he added a third, or twelve feet, which made it in all
48 feet 5 and inftead of charging to 25 grains, or rather
24 for the fake of a more eafy divifion by three, he
annulled one-third of the charge, leaving fixteen grains,
and thus he fucceeded perfectly well 5 for by 48 feet of
coated furface charged to 16 grains, three inches of
fteel wire -g^-th of an inch in diameter wrere as curioufly
melted as in any of the former experiments.
Thefe bottles, thus broken in large difeharges, feem
always to break or to be perforated nearly in the thin¬
ned:, but never in the thickeft place, which fhowrs the
neceflity of the glafs being of a confiderable thicknefs.
30. As in experiments 19. and 20. where the coated
furface in the former is but half the quantity of that in
the latter, and the former is charged to 30, and the
latter to 15 grains, to know how high 48 feet of coat¬
ing mud be charged to produce the fame effeft exact¬
ly ; and as the coating in four bottles, confifting of a
I
I C I T Y. Partlll.
little more than fix feet and a half, is contained in 48 Principles of
feet a little more than feven times 5 fo Mr Brooke ^jetftncity
tried, by charging 48 feet only to a little more than
four grains, or only about one-feventh part fo high, as ‘ment.
four times feven is 28 ; that is, but two lefs than 30 : u-—y——j
and this had exaftly the fame efieift on the wire, which
w^as xToth of an inch in diameter, and three inches
long, as it had upon the former.
31. As the laft experiment agreed fo exaflly with
experiments 19. and 20. the next thing tried was to fee
the eft'e6t of 48 feet of coated furface charged to a little
more than four grains upon fix inches of fteel ware, the
fize of the laft this was made very faintly red.
3 2. By a repetition of the laft experiment, ivith the
fame length of the fame ware, to fee how often the fame
charge might be fent through it without melting it,
and to obferve the appearance of the wire after each
fhock, he found that by the eighth fiiock it was melted
into feveral pieces. After the firft fliock, the rednefs
produced became lefs every time, even the laft time,
when it w7as feparated. By the firft (hock, though
made little more than fairly red, the wire became fo
flexible, that by a fmall addition to its own weight, it
feemed to become almoft perfectly ftraight w-hen cool¬
ed : at about the third or fourth Ihock it began to af-
fume a zig-zag appearance j after the fixth fhock the
furface of it appeared rough ; after the feventh Ihock
the furface was very roughly fcorified or fcaly j and
fome of the feales had fallen upon a piece of white pa¬
per placed at about half an inch diftance below it.
The eighth Ihock melted it in three places *, and at
thefe places where the angles appeared he ftiarpeft or
moft acute, a great number of the feales wTere driven
off about the paper, and appeared as in experiment 18)
fome of them wTere almoft one-tenth of an inch long,
and fome of them about a third or fourth part ol the
diameter of the wire in breadth, and very thin 5 after the
feventh Ihock it was Ihortened feven-fixteenths of an
inch 5 the wire wTas T4o-th of an inch in diameter.
3 3. Repeating experiment 31. again with the fame
length of wire of the fame diameter, and the fame bat¬
tery charged to the fame degree, in order to obferve
the method of the wire ftiortening, having fixed an in-
fulated gage parallel to it and at the diftance of about
a quarter of an inch from it : after the firft {hock,
which made the wire fairly red, (holding it fixed at one
end, that the ftiortening might appear all at the other,
which was held fo that it might either contracft or di¬
late) he obferved, that it ftiortened confiderably as it
cooled 5 repeating the fliock, it did the fame, and fo on
till it wras melted, which was by the eighth fliock, as
before. At the inftant when the fliock paffed through
the wire, it appeared to dilate a little ; and after it was
at the hotteft, it gradually contra&ed after every ftroke,
as it cooled, about one-fixteenth of an inch each time j
the dilatation wras fo very trifling, as to bear but a very
fmall proportion to its contraftion, and fometimes it
was doubtful whether or not it dilated at all; but after
all the obfervations it appeared oftener to dilate, than
not.
34. The fame 48 feet, negatively charged to a little
more than four grains, melted three inches of fteel wire
-y-^-th of an inch in diameter, the fame as the pofitive
charge did in experiment 30.
35. The fame battery of 48 feet of coated furface,
charged
Chap. IX. ELECT
Principles ofcharged to a little more than eight grains, melted three
inches of fteel wire, T-^oth of an inch in diameter,
by* ex peri ^ ver7 nearly in proportion to experiment 27, but
ment< here the charge was negative, and Mr Brooke fays the
v,—v.-, 1 the fufion was the moil pleafing he had hitherto had j
which he attributes to the charge having been proba¬
bly fo well adjulfed as to be exactly fufficient to melt
the wire and no more : the heat remained for the
longeft time, and the fufed metal ran into the largeft
globules $ probably the long continuance of the heat,
wTas owing to the charge being juft fufficient, and to the
fize of the lumps into which the fufed metal was formed.
36. This was a repetition of experiment 1. with
twelve inches of fteel wire -r^th of an inch in diame¬
ter, but with this difterence, that as then only nine
bottles were employed, containing about fixteen feet
of coated furface, charged to 3 2 grains, he here ufed
18 bottles containing about 3 2 fquare feet of coating
charged to only 16 grains. This wTas done to obferve
the progefs of the deftnnftion of the ware, as in experi¬
ment 3 2. as well as to prove the fimilarity of the effe6l.
The wire being the fame fize, fort of metal, and length,
as recited juft above ; the firft fhock made it red-hot
throughout its whole length attended with fmoke and
fmell, changed its colour to a kind of copperifli hue,
and fhortened it confiderably $ the fecond fiiock made
it of a fine blue, but it did not appear red, and fhortened
it more} at the third fhock it affumed a zig-zag ap¬
pearance, many radii were very vifible at the bendings,
and the ware continued to fhorten till the eleventh
fhock, wdien one of the bottles in the fecond row of the
battery was ftruck through : the fracture was covered
over with common cement, and its place fupplied by
changing place with one in the third row, fuppofing
the mended one to be the wTeakeft ; and with the bat¬
tery in this ftate he made the twelfth fhock, which fe-
parated the wire as in experiment 1. but fhortened it
only one inch.
37. A fhock from 48 feet of coated furface, charged
to eight grains, fent through three inches of copper
vvire YToth of an inch in diameter, feven times, gave
it the zig-zag appearance, but did not make it much
fhorter j the eighth fhock feparated it at one end clofe
to the forceps wiiich held it, but it did not appear to
be made at all fenfibly red-hot, notwithftanding it muft
have been often fo at the place wffiere it w7as melted j
which fpace was fo very fmall as barely to be percepti¬
ble, like as when a point is fet upon any flat furface of
iron, and a fhock from a pound phial fent through,
both the point and flat furface where the point retted,
if examined with a magnifying glafs, will be found to
have been melted, and a fpeck may be feen j but the
rednefs of the metal will fcarcely be .vifible.
38. A fhock from 48 feet, charged tq,i6 grains, was
fent through fix inches of lead wire -^th of an inch in
diameter, and melted it into many pieces.
39. A fhock from 48 feet, charged to 15 grains,
was fent through fix inches of wire like the laft, which
did not feparate it, but made it fmoke.
40. A fhock like the laft, wras fent through the fame
piece of wire a fecond time, and melted it into feveral
pieces.
I he law by wbich wires refift deftruftion, in propor¬
tion to the diameter of the wire, does not feem to be
Yol. VIL Part IX,
R I C I T Y. 713
nearly fo equable, in the lead as in the fteel wire. For Principles of
a charge of four grains, in experiment 34. melted
three inches of lead wire -g^th of an inch in diame- p,y experi-
ter j but it took a charge of about three times that 'ment.
power, to deftroy three inches of lead wire ^%-th of an —v 1
inch in diameter *, which is about double the quantity
of metal in the fame length as in that of ^th of an
inch in diameter. Thus, it is eafy to find wbat differ¬
ent refiftance a wire or any of the preceding metals,
of equal fize and length, will make to the ele&rical
ftroke.
The length of the eleclric circuit, in which the dif¬
ferent wires were placed, in the foregoing experiments,
from the neareft part of the infide to the neareft part
of the outfide of the battery, exclufive of the length of
the faid wares, was about eight feet.
41. Two gentlemen coming to fee a piece of wire
melted by eledfricity, Mr Brooke proceeded to Ihew it
them, by fixing twelve inches of fteel ware TToth
an inch in diameter, and then (fuppofing the electro¬
meter, and all other things ready placed), to charge the
battery, but the eleiftrometer did not move : neverthe-
lefs, he continued charging as he fuppofed j but ftill
the eleftrometer remained as it was, although he had
been charging much longer than wTould have been ne-
ceffary, contrary to his defign, which was to take a
fmall wire, that a fmaller charge might be fuflicient.
Having been charging a long time, Mr Brooke left off
to look about the apparatus, in order to fee if all was
right : as he wTas looking he found there wras no com¬
munication between the battery and the eleftrometer,
and he heard a flight crackling in the battery which
convinced him that it wras charged. Accordingly he
made the difeharge, expecting nothing unufual; but
the wire wras difperfed feemingly in a very violent man¬
ner. The report w’as fo very loud that their ears were
ftunned, and the flafli of light fo very great, that Mr
Brooke’s fight was quite confufed for a few feconds. 2o ;
Mr Cuthbertfon has lately contrwed an electrometer, Cuthbert-
which poffeffes all the advantages of Mr Brooke’s, add-<on’- co,n'
ed to thofe of Lane and Henly, with which he has in- P01'11^ e^ec*
genioufly combined it. rometer.
This valuable inftrument is thus deferibed by the in¬
ventor.
The eleCtrometer is reprefented in Plate CLXXXIX.
N° 2. fig. 70. GHis a long fquare piece of wood, about
18 inches long, and fix inches broad, in which are fix¬
ed three glafs fupports, DEF, mounted wath brafs balls,
a b c. Under the brafs ball a, is a long brafs hook j the
ball c is made of two hemifpheres, the under one being
fixed to the brafs mounting, and the upper turned with
a groove to flint upon it, fo that it can be taken off at
pleafure. The ball b has a brafs tube fixed to it, about
three inches long, cemented on to the top of F; and the
fame ball has a hole at the top, of about one-half inch
diameter, correfponding with the infide of the tube.
AB is a ftraight brafs wire, with a knife-edged centre
in the middle, placed a little below the centre of gra-
vity, and equally balanced with a hollow brafs ball at
each end, the centre, or axis, refting upon a proper
lhaped piece of brafs fixed in the infide of the ball c ;
that fide of the hemifphere towards c is cut open, to
permit the end c A of the balance to defeend till
it touches the ball a} and the upper hemifphere C
4 X ig
7H ELECTRICITY. Part HI.
Principlesofxs alfo cut open to permit the end c B to afeend ; / is a
weighing a certain number of grains, and made
by ex peri- in the form of a pin with a broad head ; the ball B has
ment. two holes, one at the top, and the other at the bottom 5
v-— the upper hole is fo wide, as to let the head of the pin
pafs through it, but to flop at the under one, Math its
thank hanging freely in ; a number of fuch pins are
commonly made to each electrometer of different
MTeights ; (c) -£ is a common Henley’s quadrant elec¬
trometer, and when in ufe, it is fcreMred upon the top
of c.
It is evident, from the conftruciion, that if the foot
Hand horizontal, and the ball B be made to touch it
M'ill remain in that petition wdthout the help of the
Mreight 1; and if it fhould by any means receive a very
low charge of ele&ric fluid, the two balls b, B, will re¬
pel each other ; B nail begin to afeend, and, on ac¬
count of the centre of gravity being above the centre
of motion, the afcenfion will continue till A reft upon
a. If the balance be fet again horizontal, and a pin 2’,
of any fmall weight, be put into its place in B, it will
caufe B to reft upon £, with a preffure equal to that
weight, fo that more eleftric fluid muft be communica¬
ted than before, before the balls will feparate •, and as
the weight in B is increafed or diminilhed, a greater or
lefs quantity of eledric fluid nail be required to effeft a
feparation.
When this inftrument is to be applied to a jar, or
battery, for MThich purpofe it was invented, one end of
a wire, L, muft be inferted into a hole in b, and the o-
ther end into a hole of any ball proceeding from the in-
fide of a battery, as M (d) : k muft be ferewed upon c,
rvith its index toMTards A ; the reafon of this inftrument
being added, is to flieMq by the index continuing to rife,
that the charge of the battery is increafing, becaufe the
other part of the inftrument does not a£t till the battery
has received its required charge.
If this inftrument be examined with attention, it will
be found to conftft of three eledlrometers; and anfwers
three different purpofes, namely, a Henly’s eleftrome-
ter, Lane’s difeharging electrometer, and Brooke’s fteel-
yard eleCtrometer j the firft not improved, but the tM’o
laft, which were very defective when firft invented, I
flatter myfelf are here brought to perfection. As the
only ufe of Henly’s eleCtrometer to this inftrument is,
as I have faid before, to ftiew, by its continuing to in-
creafe in divergency, that the battery continues to re¬
ceive a ftill ftronger charge, it required no improvement;
but Lane’s eleCtrometer, in its primitive ftate, could by
no means anfwer the required purpofe for batteries, be¬
caufe the ball intended to difeharge the battery, was
neceflarily placed fo near to the ball of the battery, that
duft and fibrous particles were always attracted by and
adhered between the two balls, fo as to retard the charg-
ing, and often render a high charge impoflible : where¬
as, in this, they are placed at four inches afunder; and Principles of
when the defired height of charge is obtained, and not E,e&ridty
before, the ball of the eleCtrometer moves of itfelf near- j*luftratf d
er to the ball M7hich is connected wath the outfide of the ^mem n"
battery, and caufes a difeharge. The defeCts in Brooke’s1  y ■J
iteelyard eleCtrometer Mere, ift, that it could not caufe
a dilcharge ; and 2dly, the difficulty of obferving the
firft feparation of the balls cauled great error. If it
MTere not placed in an advantageous light (which the
nature of the experiments could not always permit),
it would not be ieen, M'ithout the attention of an
afiiftant, which is fometimes unpleafant, and cannot
always be commanded. But the inftrument M7hich I
have deferibed, requires no attention or afliftance ;
for as foon as the feparation takes place betM^een B and
b, the ball A defeends, and difeharges the battery of
itfelf.
By this combination and improvements, Mre poffefs
in the prefent inftrument all that can ever be required
of an eleClrometer j namely, by we fee the progrefs
of the charge ; by the feparation of B, b, we have the
repulfive power in M-eight \ and by the ball A, the dif-^Wf‘4to
charge is caufed, when the charge has acquired the I01;"*
ftrength propofed *. 520^
With this eleCtrometer Lieutenant Colonel Haldane Col. Hal-
has made fome very ingenious experiments to determine dane’s
the exaSi charge of a battery required to produce cer-moc1,- °f
tain changes in wires of the fame kind. His method of
eftimating the force of the charge is by the number of of a bat-0
explofions that it is capable of producing in a jar con-ter/»
neCted with the outfide coating of the battery. Thus,
if the battery while charging produces three explofions
of the jar, he fays, it has received three mcafures of elec¬
tricity.
Mr Cuthbertfon having obferved that when he breath¬
ed into a jar, it M'as thus rendered capable of receiving
a higher charge, made the following experiments to af-
certain the effeCt of fuch increafed charge.
Exper. I.—Prepare the eleCtrometer in the manner Breathing
(hewn in the plate, ndth the jar M annexed, uftfich con-,r|to a jar
tains about 168 fquare inches of coating (s) : put intomakes 11
B the pin, marked 15 ; take two inches of w7atch-pen-
dulum ware, fix to each end a pair of fpring tongs, as is charge,
reprefented at G ra, hook one end to 222, and the other
to the wire N, communicating with the outfide of the
jar ; let the uncoated part of the jar be made very clean
and dry ; and let the prime conductor of an eleCtrical
machine, or a wire proceeding from it, touch the wire
L ; then, if the machine be put in motion, the jar and
eleCtrometer will charge, as will be feen by the rifing
of the index of and when charged high enough, B
will be repelled by b, and A will defeend and dif¬
eharge the jar through the wire, which w7as confined
in the tongs, and the wire \yill be fufed and run into
balls.
Exper.
(c) Inftead ot the pins, which wTere found inconvenient, Mr Cuthbertfon has lately conftruCted his eleCtrometer
ndth a Aiding piece of brafs, fo adapted to the arm of the balanced ware, as by Aiding nearer to, or farther from
the centre of gravity to denote proportional weights.
(d) A chain, or wire, or any body through which the charge is to pafs, muft be hung to the hook at 222, and
carried from thance to the outfide of the battery, as is reprefented by the line N.
(s) Take out the pin in B, and obferve whether the ball B will remain at reft upon b ; if uot turn the adjuft-
ing ferew at C‘ till it juft remains upon A.
Chap. IX. ELECT
principles of Exper, l.-r-Put into the tongs eight inches of the
i£iecT:ricity fame fort Qf wJre as before, hang one pair of tongs to the
illuftrated jiqoj, an(j apply the other to the wire which forms
' * the outlide communication : take out the pin in B, and
v_—y—.*/ put in its head one marked 30 ; all the other part of the
apparatus remaining as before, and the uncoated part of
the jar being previoufly cleaned and dried : the machine
being then put in motion, the jar and eledlromcter will
charge, as is {hewn by the rifing of the index as before ^
but as foon as the jar has received a greater quantity of
electric power than before, a fpontaneous exploixon will
happen without affedting the balls B b, becaufe the dif-
charge will have palled along the uncoated part of the
jar from the infide coating to the outixde ; whence it
follows, that, while the jar remains in that clean ftate,
it is incapable of receiving a charge high enough to af-
fedt the balls, or even a higher charge than it had re¬
ceived in the firit experiment. Let the uncoated part
of the jar be therefore rendered, in a flight degree,
damp ; which is ealily done, by breathing into the in¬
fide, through a glafs tube j put the machine in motion,
and no fpontaneous explofion will happen, but the balls
B b will repel, as in the firft experiment, and the dil-
charge will happen from A to a, and pafs through the
wire placed in the circuit *, and though it was eight
inches, it will be fufed in the fame degree as two
inches in the lait experiment, namely, the wire feen
red hot the whole length, and then fall into balls.
Very different degrees of fufion are caufed by elec*
trie difeharges, which may caufe great miftakes, if not
well attended to. It is proper to adhere to the degree
above-mentioned, and particular care ought to be taken
to lay the wire, intended for fufion, ftraight, without
any bendings or angles in it. The wire ufed in the two
lart experiments, was that which is commonly Called
watch-pendulum wire, which is flatted $ and as it ap¬
proaches very near to Inch a {harp edge as might be
fuppofed to affedl the experiment, by permitting a difli-
pation of the eleftric fluid in its paffage, round wires
were tried, and the refult was the fame.
Robii'on’s The late Ur Robifon contrived an eleclrometer on fi-
■comparable milar principles with that of Mr Brooke, but much fu-
ele<ftrorne- perior to it in fimplicity of conitrudtion, and not infe-
ter’ rior to any which have been invented in point of ac*
• curacy.
Plate Fig. 71. exhibits a front view of this inllrument,
CTXXXIX. which is thus conitru£ted. A polilhed brafs ball
2* A, a quarter of an inch in diameter, is fixed on the
point of a common needle about three inches long, and
as {lender as can be procured of that length. On the
other end of the needle is fixed a ball of amber, glafs, or
other folid non-conducting fubtlance, of about half an
inch or three-quarters of an inch in diameter. This ball is
fixed in fuch a way as that the needle does not quite
reach to its furface, though the ball F mufl: be com¬
pletely perforated. From the eledtric ball there paffes
a {lender glafs rod, F, E, L, bent at right angles at E,
fo that the part FE is about three inches long, and
the other extremity L is immediately oppofite to the
centre of the ball A. A piece of amber C, cut fo as to
have two parallel cheeks, is fixed on the extremity L of
the glafs rod. For the principal part of the inftrument,
a ftrong dry filk thread is to be prepared by holding it
perpendicular in melted fealing-wax, till it fhall be fully
penetrated by the wax, fo as to retain a thin coating of
H I c I T Y. 71s
it. The thread, thus coated, muft be kept extended, Principles of
fo that it may be quite ftraight, and it muft be made ^j.^ated
perfeftly fmooth by holding it before a clear fire and ^ eXj)eri.
rolling it on a fmooth plane. It is then to be paffed ment.
through a fmall cube of amber, that has two holes drill- " v"
ed in two of its oppofite faces, perpendicularly about
half way to the ftalk. By thefe holes the cube is fiif-
pended, fo as to move readily, on two fine brafs pins,
between the cheeks of the piece of amber at L. The
waxed thread is about fix inches long, and is equally
divided by the amber cube. To one end of it, B, is
fixed a ball of fome conducting fubftance, as of very thin
poliihed metal, or gilt and bumilhed cork, a quarter
of an inch in diameter. The other extremity, D,
paffes through a cork ball, fo as to move with fome
fridtion.
This part of the inftrument is fo conftrudled, that
when FE is perpendicular to the horizon, and the ftalk
BD, with its balls, is allowed to hang freely, the ball B
juft touches the ball A. This pofition is reprefented in
fig. 72.
The ball F is fixed to one end of a glafs rod FI
made to pafs perpendicularly through the centre of a
graduated circle GHO, and furnifhed at its other ex¬
tremity I with a knobbed handle of box wood. HK is
the ftand of the eledlrometer, in the head of which is a
hole in which the rod FI moves fmoothly but not eafi-
ly. Farther, there is adapted to the glafs rod FI an in¬
dex NH that turns round it. This index is fo placed
as to be parallel to a line LA drawn through the centre
of the ball A. Now, as the circle is divided into 360
degrees, o being marked above and 90 on the right
hand $ the index will point out the angle which the
line L A makes with the vertical line. It is convenient
to have another index on the rod FI turning ftilHy
round it, and extending confiderably beyond the
circle.
The method of ufing this inftrument will be fliewn
when we fpeak of the law of eledtric adlion in the next
part.
Chap. X. Of the EleEtrophorus.
... 207
The eledtrophorus is an inftrument invented by Defcnptioft
Signior Volta of Como. It generally confifts of two ot the elec-
parts *, a round plate of metal, or of wood, made per- troP^orus*
fedlly free from points and edges, and covered with tin-
foil •, as A fig. 73 : and another circular plate of any
condudling fubftance covered with a coating of fome re-
finous eledlric, generally of lac diffolved in alcohol,
melted fealing-wax, pitch, or of fulphur ; as B. The
firft plate is furniftied with a glafs handle, or with filk
firings, fo that it may be occafionally infulated : to
this plate Volta has given the name of Scudo.
Sometimes the apparatus is made in three parts, i. e.
the refinous eledlric is formed into a cake independent
of the plate B, and this is the moft convenient method
for experiment. To thefe three parts Dr Robifon has
given the following names j viz. the refinous eledlric he
calls the cake, the plate B, the foie, and the plate A the
Cover ; and thefe names we ihall adopt for the fake of
convenience. For the purpofe of exhibiting the appear-
ances which we are about to deferibe in the moft brilliant
manner, the feveral parts may be made very thin in pro¬
portion to their circumference j but for illuftrating the
4X2 theory
716
E L E C T R
Prineiples°f theory of the inftrument, which we (hall explain in the
following part, they ftiould be made of confiderable
byexperi- t|1^c^ne^s* The foie ihould be provided with an infula-
ment. * ting Hand.
'' ■ '--v—, ■1 The general appearances which have been obferved
with this apparatus may be reduced to the following
heads.
1. If the cake, after being juft formed, be fuffered to
remain on the foie, till it be perfectly cool and hard,
while the foie is infulated; on examination the whole
wall be found negatively eledtric, and on applying the
finger to any part of it, efpecially the foie, a fpark is
produced. If the apparatus be now fuffered to remain
at reft, its electricity gradually becomes weaker, and at
length entirely difappears. It may, however, be again
produced by rubbing the cake with a piece of new flan¬
nel, or, what is better, a piece of hare or mole fkin with
the fur on, made dry and warm. If after the cake has
been thus excited, the cover be placed on it, by means
of its infulating handle, and if it be again lifted off,
without being Vouched, no electricity whatever can be
obferved in the cover.
2. If, however, the cover while in contaCt with the
cake, be touched with the finger, a fmart pungent fpark
will be obtained from the cover ; and if, while the
finger touches the cover, the thumb is placed upon the
foie, a fenfible fhock will be felt between the finger and
thumb.
3. After the above fpark or fhock has been obtain-
t*J, the eleCtricity of the eleCtrophorus difappears, and
the apparatus is faid to be dead ; no figns of eleCtricity
appearing in either foie or cover, fo long as the latter re¬
mains in contaCt with the cake.
4. But if the cover be railed to fotne diftance from
the cake, and in a direction parallel to it, and if the
cover be touched while held in this pofition, a fmart
fpark will appear between it and the finger, and will
even ftrike to fome diftance. This fpark will be more
remarkable, if obtained from the upper furface of the
cover, efpecially from its edge, which, if it has not been
well rounded, will even throw off fparks into the air.
The fpark received from the cover under thefe circum-
ftances, is however, not fo pungent as that mentioned
in N° 2, refembling a fpark from any eleCtrified con¬
ductor.
5. When the cover is thus raifed from the cake, the
former is found pof lively eleCtrified, and the latter, as
before, negatively.
6. But the eleCtricity of both cover and cake, while
in contaCt, is negative.
7. The appearances above deferibed may be repeated
for a confiderable time, with apparently undiminilhed
vivacity, without re-exciting the cake by friction 5 the
apparatus has been obferved to retain its eleCtric power,
even for feveral months. Hence it ferves as a kind of
eleCtrical magazine, and may be repeatedly employed
for charging jars, either pof lively, by imparting to the
jar the eleCtric fpark from the cover while raifed from
the cake •, or negatively, by receiving the fparks from
the covet* in contaCt with the cake. From this property
of retaining the eleCtric power for fo long a time, Signior
Volta denominated the apparatus eleBrophorus, or elet-
troforo perpetuo.
8. If, before placing the cover on the cake, the foie
, by experi-
means Jo ptmgent nient.
the foie has not been infix-i——v—
208
1 c I T Y. Partin.
has been infulated, the fame fpark may be obtained Puncipies of
from the cover, and the fame ftiock may be felt on ^!e<ftrrcity
touching both cake and cover at the fame time 5 but “lu^rated
the fpark, in this cafe, is by no means fo
as that obtained when
lated.
9. If, when the foie has been infulated, the cover
be again lifted to a confiderable diftance from the
cake, the foie will be found eleCIrical, and its elec¬
tricity will be the lame as that of the cake, or ne¬
gative.
1 °: jTter touching both foie and cover, the cover
be raifed from the cake, by its infulating. handle, and
again replaced upon the cake without being touched
while feparate, the whole apparatus is found to poflefs
no eleClricity.
11. If both foie and cover be inaClive after being
joined, they will, when feparated, fhow oppofite elec¬
tricities ; the cover being electrified pof lively and the
lole negatively.
12. If both cover and foie be rendered inadlive
while feparate, they will, when placed in contadl, be
found to poffefs the eledtricity oppofite to that of the
cake, i. e. they will together be in a ftate of politive
eledlricity.
It is of little confequence what fubftance forms the ^ Cavaj
bafis to which the electric coating is applied 5 formerly Jo’s experi-
a glafs plate was employed, and this was coated with mem’s on
various refinous eledtrics. Mr Cavallo, who made fe-the ele<ftr«>~
veral experiments on the conftrudHon and phenomena Qf Phorus*
the eledlrophorus, found that the moft convenient elec¬
tric was made with the fecond fort of fealing-wax fpread
upon a thick glafs plate. A plate made by him after
this manner, the diameter of which was no more than
fix inches, was, when once excited, capable of charg¬
ing a coated phial fo ftrongly, that by the explofion, a
card could be perforated •, this phial might be charged
feveral times fucceflively, without again exciting the
plate. Sometimes the cover, when feparated from the
plate, was fo itrongly eledtrified, that it darted ftrong
fiafhes towards the table on which the eledlric plate was
laid, and even into the air. “ The power of fome of
my plates,” fays Mr Cavallo, “ is fo ftrong, that fome-
times the eledlric plate adheres to the metal when this
is lifted up; nor will they feparate even wdien the
metal plate is touched with the finger, or other con-
dudfor.
“ If, after having excited the fealing-wax,” conti¬
nues he, “ I lay the plate with the wax upon the table,
and the glafs uppermoft, i. e. contrary to the common
method, then, on making the ufual experiment of put¬
ting the metal plate on it, and taking the fpark &c.
I obferve it to be attended with the contrary eledlrici¬
ty ; that is, if I lay the metal plate upon the eledlric
one, and while in that fituation touch it with an inful-
ated body, that body acquires the pof live eledlricity,
and the metallic, removed from the eledlric plate,
appears to be negative 5 whereas it would become ppfi
live if laid upon the excited wax. This experiment, I
find, anfwers in the fame manner, if an eledlric plate
is ufed which has the fealing-wax coating on both
fides, or one of Mr Adams’s, which has no glafs
plate.
“ If the brafs plate, after being feparated from, be
prefented
Chap.
ELECTS
edge towards the wax, lightly
X.
Principleso< prefented with the
Electricity touching it, and thus be drawn over its furface, I find
that the electricity of the metal is abforbed by the feal-
vpvneri- an(j t|]e plate lofes part of its
power ; and if this operation be repeated five or fix
times, the electric plate lofes its power entirely, fo that
a new excitation is neceflary to revive it.”
There is one part of Mr Cavallo’s experiments upon
the electrophorus, which by no means accords with the
account of the phenomena given by us in Nos 8, 9,
JO, II, 12.
If, fays he, “ inllead of laying the electric plate upon
a table, it be placed upon an eleftric Hand fo as to be
accurately infulated, then the metal plate let on it, ac¬
quires fo little electricity that it can only be difeovered
by an electrometer.
“ Upon an ele&ric Hand E fig. 73, I placed a circular
tin plate, nearly fix inches in diameter, which by a
{lender wire El, communicated with an electrometer of
pith balls G, which was alfo infulated upon the elec¬
tric Hand F. I then placed the excited eleCtric plate
D, of fix inches and a quarter in diameter upon the tin
plate with the wax uppermoft, and on removing my
hand from it, the eleftrometer G, which communi¬
cated with the tin plate, i. e. with the under fide of the
eleftric plate, immediately opened with negative elec¬
tricity,” Sec. *.
It is fomewhat extraordinary that fo expert an elec¬
trician as Mr Cavallo, Ihould alfert that an infulated
eleftrophorus Ihows weaker figns of ele&ricity than one
uninfulated } whereas, in fact, the electricity in the for¬
mer cafe is generally llronger than in the latter, and
always fo Itrong as to afford fparks from fome part of
the apparatus.
Mr G. Morgan has given us fome valuable experi-
gan’s expe- mental obfervations on the Infulated Elelirophorus.
riments. piis apparatus confilts of a rounded piece of wood, AB
fig. 74. with fmootli edges and covered with tin-foil,
placed on an infulating Hand CD. On this board or
foie is placed the eleCtric plate or cake ; a b \s a wire
with a brafs ball from which are hung the eleCtrome-
ter balls g h. G reprefents the feudo or cover. After
relating the ufual appearances produced by friction,
he proceeds to deferibe thofe which arife from con¬
necting the cake with oppofite fides of a Leyden
phial.
“ When the negative lurface of a charged phial is
placed on the excited furface, by bringing the hand
into contaft with the oppofite fide of the phial, a fpark
is inftantly communicated, and the pith-balls g and //,
feparate negatively.
If the phial be taken off, and the feudo placed in
its room, no change is obfervable on the fubfequent re¬
moval of the feudo, provided, that no communication
has been formed between it and the ground. When fuch
a communication is formed, a charge is communicated,
and the feudo and the balls are in oppofite Hates of
eleClricity.
If the pofitive fide of a Leyden phial be placed on
the excited furface, the pith-balls feparate pofitively.
It muff be obferved that thefe experiments are made
with a refinous fab fiance.
The appearances of the pith-balls and feudo are
materially varied, if the Leyden phial be applied to the
* Cavallo's
EleShicity,
vol. ii.
209
Mr Mor-
I C I T Y. 717
eleClrophorus while the feudo is in contaCl with its ex-Principles of
cited furface. If the negative fide of the phial be ap-
plied, and a fpark be taken from the pofitive, the pith- 1:)y experi-
balls immediately feparate negatively ; but on taking ment.
up the feudo, they immediately clofe, and as rapidly—y——'
feparate again pofitively.
If after the phial is removed, the hand be applied to
the feudo before it is raifed, a fmall fpark ftrikes into
the hand ; but on railing the feudo, the balls clofe and
feparate infiantaneoully, and give figns of pofitive elec¬
tricity.-—If the feudo and the brafs plate be connected,
either by an infulated or uninfulated difeharging rod,
the balls clofe and feparate again, and the feudo, upon
being raifed, receives a vigorous negative fpark.
It is obvious that in all the preceding experiments,
the brafs plate continues unchangeably adherent to the
lower furface, while the feudo only, or the conducting
fubftance in connection with the upper furface, is im¬
moveable. It is of importance that we Ihould know
the confequences of making both the metallic furfaces
moveable.
But this is not an eafy matter 5 it is very difficult to
get a refinous fubffance thin enough, and at the fame
time firm enough, for the purpofe. The perfeCt laminae
of talc, which I have been able to procure, are too
fmall to be ufed with any fatisfaClion 5 I have therefore
had recourfe to glafs for the purpofe. The refult of
my repeated trials is the following.
Having fubftituted a glafs plate, about twelve inches
in diameter, and one fourth of an inch thick, in the
room of the refinous fubftance, and having refted it on.
a ground metallic plate, five inches in diameter, and
well conneded with the pith-balls g and //, I expofed it
to the fparks of a conductor charged pofitively, and
kept my hand at the fame time in connexion with the
wire a b. The plate took a confiderable charge 5 its
upper fide was unequivocally pofitive, and its lower
fide negative. I placed the feudo on the glafs thus
charged, and approaching it with my hand, I received
a fpark. I then approached a b with my hand, and
received another. By alternate approaches of this kind,
four or five times repeated, the fparks became weaker
and weaker till they difappeared ; the feudo was then
raifed, and was ftrongly negative ; but the pith-ball,
on the removal of the feudo, clofed and feparated pofi¬
tively.
I then made the lower the upper furfaee ; and placing
the feudo upon it, formed the communication, as in the
preceding part of the experiment 5 but upon being
raifed, the feudo was ftrongly pofitive, and the balls'
negative.
But if, previous to the placing the feudo on the
glafs, the pith-balls be carefully difeharged of all ad¬
herent eleCtricity, both the upper and lower fides of
the glafs will be charged with pofitive eleCtricity, or:
will give figns of their being in the fame ftate at the
fame time.
It is obfervable that the fucceflion of eleCtrics, in
the preceding experiments feems to vary according to
the priority of contaCt given to the wire or the feudo.
But though this happens moft frequently, yet fuch
anomalies take place as not to juftify us in confidering
this fingular connection of. diverfities as by any means * Morgan s
certain*”. Zeflura,.
Chap^vo1,
7i9 ELECT
Principles of
TilecTricity Chap. XI. Obfervations and Experiments on Excita-
byexperi'! tWH and Ele^rical Machines, with the defcription
ment. °f afl Electrical Machine in which Silk is employed
*—v—J injlead of Glafs.
Nicbolfon’s Mr Nicholfon publlflied in the Phil. Tranf. for
experi- f°me valuable obfervations on the bell means of
excitation» which we fliall here extraft.
^ I. A glals cylinder was mounted, and a culhion ap¬
plied with a filk dap, proceeding from the edge of the
culhion over its furface, and thence half round the cy¬
linder. The cylinder was then excited by applying an
amalgamed leather in the ufual manner. The electri¬
city was received by a conductor, and palled off in
(parks to Lane’s eleCtromcter. By the frequency of
thefe fparks, or by the number of turns required to
caufe fpontaneous explolion of a jar, the ftrength of the
excitation was afcertained.
2. The culhion was withdrawal about one inch from
the cylinder, and the excitation performed by the lilk
only. A Itream of fire was feen between the culhion
and the lilk j and much fewer fparks paffed betwreen
the balls of the electrometer.
3. A roll of dry filk w-as interpofed, to prevent the
Itream from palting between the culhion and the filk.
X ery fewr fparks then appeared at the eleCtrometer.
4* -X metallic rod, not infulated, wras then interpofed
inltead of the roll of filk, fo as not to touch any part
of the apparatus. A denle Itream of eleCtricity appear¬
ed between the rod and the filk, and the conductor gave
very many fparks.
5. The knob of ajar being fubftituted in the place
of the metallic rod, it became charged negatively.
6- The lilk alone, with a piece of tin-foil applied
behind it, afforded much eleCtricity, though lefs than
when the culhion was applied with a light preffure.
The hand being applied to the filk as a culhion, pro¬
duced a degree of excitation feldom equalled by any
other culhion.
7. The edge of the hand anfwered as wxril as the
palm.
8. When the excitation by a culhion was weak, a
line of light appeared at the anterior part of the culhion,
and the lilk w7as Itrongly difpofed to receive eleCtricity
from any uninfulated conductor. Thefe appearances
did not obtain wdien the excitation wras by any means
made very Itrong.
9. A thick lilk, or twro or more folds of filk, ex¬
cited w'orfe than a fingle very thin flap. I ufe the fiik
which the milliners call Perlian,
10. When the filk wras feparated from the cylin¬
der, fparks paffed between them ; the filk was found
to be a wreak negative, and the cylinder in a pofitive
an Itate.
The filk The foregoing experiments Ihow that the office of
^rincfal ^ ^ not mere^y to prevent the return of eleCiri-
caufe of ex- cJt7 from tlle. cylincle1' to the Culhion, but that it is the
citation. chief agent in the excitation ; while the culhion ferves
only to fupply the eleCtricity, and perhaps increafe the
preffure at the entering part. There likewufe feems to
be little reafon to doubt but that the difpofition of the
eleCtricity to efcape from the furface of the cylinder is
not prevented by the interpofition of the filk, but by a
compenfation after the manner of a charge j the lilk
2
R I C I T Y. Part nr.
being then as Itrongly negative as the cylinder is pofi- Principles of
tive} and, laltly, that the line of light between the Electricity
filk and culhion in wTeak excitations does not confilt of ^lu^Iattfl
returning eleCtricity, but of eleCtricity which paffes to
the cylinder, in confequence of its not having been ^ , ‘ f
fufficiently fupplied during its contaCt with the rubbing
furface.
11. When the excitation wras very Itrong in a cy¬
linder newly mounted, flalhes of light wTere feen to fly
acrofs its infide, from the receiving furface to the liar-
face in contaCt wdth the culhion, as indicated by the
brulh figure. Lhefe made the cylinder ring as if (truck
with a bundle of fmall twigs. They feem to have arifen
from part of the eleCtricity of the cylinder taking the
form of a charge. 1 his appearance was obferved in a
9-inch and a 1 2-inch cylinder, and the property went
off in a few weeks. Whence it appears to have been
chiefly occafioned by the rarity of the internal air pro¬
duced by handling, and probably reltored by gradual
leaking of the cement. 1 2
13. With a view to determine what happens in the State of tli#7
infide of the cylinder, recourfe was had to a plate ma-infide of a
chine. One culhion was applied with its lilken flap, cylinder 4
The plate was 9 inches in diameter and T25ths of an citation d*"-
inch thick. During the excitation, the furface oppo- termmed.6*
fite to the culhion Itrongly attracted eleCtricity, which
it gave out when it arrived oppcfite to the extremity of
the flap : fo that a continual Itream of eleCtricitv paffed
through an infulated metallic bow terminating in balls,
which were oppofed, the one to the furface oppofite
the extremity of the filk, and the other oppofite to the
culhion 5 the former ball {bowing pofitive and the lat¬
ter negative figns. The knobs of two jars being fub¬
ftituted in the place of thefe balls, the jar applied to
the furface oppofed to the cuflaion was charged nega¬
tively, and the other pofitively. This difpofition of
the back furface feemed, by a few trials, to be weaker,
the ffronger the aCtion of the culhion, as judged by the
eleftricity on the culhion fide.
Hence it follows, that the internal furface of a cy¬
linder is fo far from being difpofed to give out eleftri-
city during the friftion by which the external furface
acquires it, that it even greedily attraCls it.
13. A plate of glafs was applied to the revolving
plate, and thrufl: under the culhion in fuch a manner
as to fupply the place of the filk flap. It rendered the
eleCfricity ftronger, and appears to be an improvement
of the plate machine.
14. Two culhions wrere then applied on the oppo¬
fite furfaces with their filk flaps, fo as to clafp the plate
between them. The eleCtricity was received from both
by applying the finger and thumb to the oppofite fur-
faces of the plate. When the finger was advanced a
little towards its correfpondent culhion, fo that its di-
llance was lefs than between the thumb and its culhion,
the finger received Itrong eleCtricity, and the thumb
none •, and, contrariwife, if the thumb were advanced
beyond the finger, it received all the eleCtricity, and
none paffed to the finger. This eleCtricity was not
ttronger than was produced by the good aCtion of one
culhion applied fingly.
15. The cufliion in experiment 12. gave molt elec¬
tricity when the back furface was fupplied, provided
that furface was fuffered to retain its eleCtricity till the
rubbed furface had given out its eleCtricity.
From
hap.
machine.
214
Velocity
XI. ELECT
Principles of From the two laft paragraphs it appears, that no
Electricity advantage is gamed by rubbing both furfaces 5 but that
illufti atu a wejj managed friition on one furface will accumulate
as much electricity as the prefent metliods of excitation
feexn capable of collecting $ but that, when the exci-
2r3 tation is weak, on account of the eleCtric matter not
ta^ained Pa^'ing with fufficient facility to the rubbed furface,
by rubbing the friction enables the oppofite furface to attract or
two fides receive it, and if it be fupplied, both furfaces will pafs
of the plate 0ff in the politive Hate', and either furface will give out
more ele£tricity than is really induced upon it, becaufe
the electricity of the oppofite furface forms a charge.
It may be neceffary to obferve, that I am [peaking of
the facts or effects produced by friftion 5 but how the
rubbing furfaces aft upon each other to produce them,
whether by attraction or otherwife, we do not here in¬
quire.
16. When a cylinder is weakly excited, the appear¬
ances mentioned (par. 8.) are more evident the more
rapid the turning. In this cafe, the avidity of the lur-
face of the cylinder beneath the filk is partly fuppiied
from the edge of the filk, which throws back a broad
cafcade of fire, fometimes to the diftance of above 1 2
inches. From thefe caufes it is that there is a de-
neceffary to terminate velocity of turning required to produce the
produce^the maximum of intenfity in the conduftor. The Itronger
gree of ex- t^e exchation, the quicker may be the velocity 5 but
citation. it rarely exceeds five feet of the glafs to pafs the culhion
in a fecond.
17. If a piece of filk be applied to a cylinder, by
drawing down the ends fo that it may touch half the
circumference, and the cylinder be then turned and ex¬
cited by applying the amalgamed leather, it will be¬
come very greedy of eleftricity during the time it paffes
under the filk. And if the entering furface of the
glafs be fupplied with eleftricity, it will give it out at
the other extremity of contaft •, that is to fay, if infu-
lated conduftors be applied at the touching ends of the
filk, the one wrill give, and the other receive, eleftri¬
city, until the intenfities of their oppofite Hates are as
high as the power of the apparatus can bring them ;
and thefe Hates will be infiantly reverfed by turning
the cylinder in the oppofite direftion.
As this difeovery promifes to be of the greateH
ufe in eleftrical experiments, becaufe it affords the means
of producing either the plus or minus Hates in one and
the fame conduftor, and of inHantly repeating experi-
conduftor. ments with either power, and wnthout any change of
pofition or adjuHment of the apparatus, it evidently de-
ferved the moH minute examination.
18. There was little hope (par. 6.) that cufhions
could be difpenfed with. They were therefore added •,
and it was then feen, that the eleftrified conduftors
were fupplied by the difference between the aftion of
the culhion which had the advantage of the filk, and
that which had not ; fo that the naked face of the cy¬
linder was always in a ffrong eleftric Hate. Methods
were ufed for taking off the preflure of the receiving
cufnion •, but the extremity of the filk, by the con-
ffruftion, not being immediately under that culhion,
gave out large Hallies of eleftricity with the power that
was ufed. Neither did it appear prafticable to prefent
a row7 of points or other apparatus to intercept the
eleftricity wdiich flew round the cylinder ; becaufe
fuch an addition would have materially diminifhed the
R I C t T Y.
719
215
How to
produce
both elec¬
tricities in
the fame
intenfity of the conduftor, which in the ufual way was Principles of
fuch as to fiaffi into the air from rounded extremities
of four inches diameter, and made an inch and half ball ^ eXpfiri_
become luminous and blow like a point. But the great- ment.
eff inconvenience was, that the tw7o Hates with the L——v "■ f
backward and forward turn were feldom equal •, becaufe
the difpofition of the amalgam on the filk, produced
by applying the leather to the cylinder in one direftion
of turning, was the reverfe of what mufi take place
when the contrary operation was performed.
Notw ithffanding all this, as the intenfity with the
two cufliions was fuch as moH operators would have
called firong, the method may be of ufe, and I Hill
mean to make more experiments when I get pofleflion
of a very large machine w7hich is now in hand. 21(j
19. The more immediate advantage of this difeo-improved
very is, that it fuggeHed the idea of two fixed cufliions method of
with a moveable filk flap and rubber. Upon this pnn_ excitation,
ciple, w hich is fo Ample and obvious, that it is wonder¬
ful it fliould have been fo long overlooked, I have con-
ftrufted a machine with one conduftor, in which the
two oppofite and equal Hates are produced by the Ample
procefs of loofening the leather rubber, and letting it
pafs round with the cylinder (to which it adheres),
until it arrives at the oppofite fide, where it is again
fallened. A wifli to avoid prolixity prevents my deferib-
ing the mechanifm by which it is let go and faflened
in an inflant, at the fame time that the cufliion is made
either to prefs or is withdrawn, as occafion requires.
20. Although the foregoing feries of experiments
naturally lead us to confider the filk as the chief agent
in excitation ; yet as this bufmefs wras originally per¬
formed by a cufliion only, it becomes an objeft of in¬
quiry to determine what happens in this cafe. 2Iy
21. The great Beccaria inferred, that in a Ample In what
cufliion, the line of fire, which is feen at the extremity n?ani?er ?x-
of contaft from which the furface of the glafs recedes,Cltafl0n 18
confifls of returning eleftricity, and DrNooth ground- byVfimple
ed his happy invention of the filk flap upon the fame rubber
fuppofition. The former afferts, that the lines of fightWitll0ut
both at the entering and departing parts of the furface a
are ablolutely fimilar; and thence infers, that the cufhicn
receives on the one fide, as it certainly does on the
other. I find, how7ever, that the faft is direftly con¬
trary to this affertion ; and that the oppofite inference
ought to be made, as far as this indication can be reck¬
oned conclufive : for the entering furface exhibits ma¬
ny luminous perpendiculars to the cufliion, and the de¬
parting furface exhibits a neat uniform line of light.
This circumflance, together with the confideration that
the fine of fight behind the filk in par. 8. could not
confifl of returning eleftricity, fliow7ed the necefiity of
farther examination. I therefore applied the edge of
the hand as a rubber, and by occafionally bringing for¬
ward the palm, I varied the quantity of eleftricity
which paffed near the departing furface. When this was
the greateH, the [parks at the eleftrometer were the
mofl numerous. But as the experiment was liable to the
objeftion that the rubbing furface was variable, I palled
a piece of leather upon a thin flat piece of wood, then
amalgamed its wdiole furface, and cut its extremity off
in a neat right fine clofe to the wood. This being ap¬
plied by the conflant aftion of a fpring againfl the cy¬
linder, produced a weak excitation*, and the fine where
the contaft of the cylinder and leather ceafed (as abrupt-
meats.
720 • ELECT
Principles0fly as poffible) exhibited a very narrow fringe of light,
"f/luftra^ed J^-not^er P^ece wood was prepared of the fame wfdth
by e/peri- ?s t^ie rubber, but one quarter of an inch thick, with
ment. ^ts edges rounded, and its whole furface covered with
Y-—‘ tin-foil. This was laid on the back of the rubber, and
was there held by a fmall fpring, in fuch a manner as
that it could be Hided onward, fo as occafionally to
projedl beyond the rubber, and cover the departing and
excited furface of the cylinder without touching it.
The fparks at the eleftrometer were four times as nu¬
merous when this metallic piece was thus projected;
but no electricity was obferved to pafs between it and
the cylinder. The metallic piece was then held in the
hand to regulate its diilance from the glafs : and it was
found, that the fparks at the eleftrometer increafed in
number as it was brought nearer, until light appeared
between the metal and the cylinder •, at which time
they became fewer the nearer it was brought, and at
2l8 laft ceafed when it was in contadl.
Conclufions The following conclulions appear to be deducible
from thefe from thefe experiments. 1. The line of light on a cy-
expen- Under departing from a limple culhion confifls of re¬
turning eleftricity : 2. The projefting part of the cu-
fhion compenfates the ele&ricity upon the cylinder, and
by diminilhing its intenfity prevents it ftriking back in
fuch large quantities as it would otherwife do : 3. That
if there was no fuch compenfation, very little of the
excited ele&ricity would be carried off: And, 4. That
the compenfation is diminilhed, or the intenlity increa¬
fed, in a higher ratio than that of the dillance of the
compenfating fublfance ; becaufe, if it were not, the e-
leftricity which has been carried off from an indefinite¬
ly fmall diflance, would never Hy back from a greater
diflance and form the edge of light.
22. I hope the confiderable intenfity I fliall fpeak
of will be an apology for defcribing the manner in
eledlriat°* ^ produce it. I wifh the theory of this very
tp a great °bfcure procefs were better known ; but no conjec-
degree. ture of mine is worth mentioning. The method is as
follows:
Clean the cylinder, and wipe the filk.
Greafe the cylinder by turning it againfl a greafed
leather till it is uniformly obfcured. I ufe the tallow
of a candle.
Turn the cylinder till the filk flap has wiped off fo
much of the greafe as to render it femitranfparent.
Put fome amalgam on a piece of leather, and fpread
it well, fo that it may be uniformly bright, Apply
this againft the turning cylinder. The friction will
immediately increafe, and the leather mufl not be re¬
moved until it ceafes to become greater.
Remove the leather, and the action of -the machine
will be very firong.
My rubber, as before obferved, confifts of the filk
flap palled to a leather, and the cufhion is prefied againfl
the filk by a flender fpiral fpring in the middle of its
back. Tire culhion is loofely jetained in a groove,
and reds againfl: the fpring only, in fuch a manner that
by a fort of libration upon it as a fulcrum, it adapts
itfelf to all the irregularities of the cylinder, and never
fails to touch it in its whole length. There is no ad-
juftment to vary the preflfure, becaufe the preflure can¬
not be too fmall when the excitation is properly made.
Indeed the adual withdrawing of the cufhion to the
l
R I C I T Y.
Part III.
219
How to in¬
creafe the
diftance of -^th of an inch from the filk, as in par. 2. Principles of
will not materially afieft a good excitation. Electricity
The amalgam is that of Dr Higgins, compofed ^'uftrate.ti
of zinc and mercury. If a little mercury be added to J
melted zinc, it renders it eafily pulverable, and more
mercury may be added to the powder to make a very
foft amalgam. It is apt to cryftallize by repofe, which
feems in fome meafure to be prevented by triturating it
with a fmall proportion of greafe 5 and it is always of
advantage to triturate it before ufing.
A very ftrong excitation may be produced by ap¬
plying the amalgamed leather to a clean cylinder with
a clean filk : but it foon goes off, and is not fo ftrong
as the foregoing, which lafts feveral days. 220
23. To give fome diftimftive criterions by which Eft'edb of
other electricians may determine whether the intenfityc1lfferent
they produce exceeds or falls ftiort of that which thisexrkfdln
method affords, I lhall mention a few faCts. ti4s man.
With a cylinder 7 inches' diameter and culhion 8ner.
inches long, three brulhes at a time conftantly flew out
of a 3-inch ball in a fucceflion too quick to be count¬
ed, and a ball of inch diameter was rendered lu¬
minous, and produced a ftrong wind like a point. A
9-inch cylinder with an 8-inch cufhion occafioned fre¬
quent flafhes from the round end of a conduftor 4 inches
diameter: with a ball of 2^- inches in diameter the flalhes
ceafed now and then, and it began to appear luminous:
a ball of 1 inch diameter firft gave the ufual flaflies ;
then, by quicker turning, it became luminous with a
bright fpeck moving about on its furface, while a con-
ftant ftream of air ruffled from it : and, laftly, when
the intenfity was greateft, brufties of a different kind
from the former appeared. Thefe were lefs luminous,
but better defined in the branches j many ftarted out
at once with a hoarfe found. They were reddiih at
the item, fooner divided, and were greenifli at the point
next the ball, which was brafs. A ball of -f^ths of an
inch in diameter was furrounded by a Heady faint light,
enveloping its exterior hemifphere, and fometimes a
fialh ftruck out at top. When the excitation was
ftrongeft, a few flalhes ftruck out fidewife. The ho¬
rizontal diameter of the light was longeft, and might
meafure one inch, the ftem of the ball being vertical.
With a x 2-inch cylinder and rubber of 74 inches,
a 5-inch ball gave frequent flalhes, upwards of 14
inches long, and fometimes a 6-inch ball would flafli.
I do not mention the long fpark, becaufe I was not
provided with a favourable apparatus for the two lar¬
ger cylinders. The 7-inch cylinder affords a fpark of
io4 inches at beft. The 9-inch cylinder, not having
its conductor infulated on a fupport fufficiently high,
afforded flaflies to the table which was 14 inches di-
ftant. And the I 2-inch cylinder, being mounted on¬
ly as a model or trial for conftru£ling a larger appara¬
tus, is defective in feveral refpe&s* which I have not
thought fit to alter. When the five-inch ball gives
flaflies, the cylinder is enveloped on all fides with lire
which rulhes from the receiving part of the conductor.”
It is of confequence that electricians fliould employ uiual me-
fome common method of eftimating the power of their thods of
machines, fo as to admit of comparing thofe of diffe- eitimating
rent lizes or conftruCtions. This is ufuaffy done by de-
fcribing the length and appearance of the Ample fpark pUWer 0f
drawn from the prime conduftor j or the diftance to eledtrical
which machine^.
Chap.
rum s ma
thines.
XL ELECT
Principles of which the attractive power of the prime conductor is
Eledtricity rendered perceptible on a thread or other pendulous
ilmftrated |3od^. or eXpl0r10n produced from a certain
^ent.^ extent of coated furface. The firft of thefe methods is
v-L-j fubjeCt to confiderable variation from the circumftances
mentioned in (88), and the fecond is fubjeCl to modi¬
fication both from the ftruCture of the lefs effential parts
of the machine, and from the dimenfions and figure of
the apartment in which the experiments are made.
The laft method is therefore mod generally employed,
and according to this, Mr Nicholfon gives the follow¬
ing eftimate of the comparative power of Van Marum’s
a,, two machines defcribed in n° 48, 49.
Compara- By 150 turns of his new machine, 90 jars, each con-
live power taining upwards of a fquare foot of coated glafs, were
of Van Ma-charge(i fQ that the battery difcharged itfelf. I he
great Teylerian machine, with two plates of fixty-five
inches diameter, in its original date, before Dr Van
Marum’s improved rubbers were applied to it, never
charged the fame battery, in the mod favourable cir-
cumitances, in lefs than 66 turns. It follows, there¬
fore, that this fmall and fimple machine exhibited
-//o-ths, or about £ths, of the power of that great ma¬
chine in its fird date j and probably, if the circum-
dances had been alike favourable in each, it would
have amounted to one half. The doctor has grounded
a calculation upon thefe facts 5 but as he dates the rub¬
bed furfaces of thefe two machines, probably by fome
midake in calculation, to be 1243 anc^ 9636 fquare
inches refpedtively, I (hall repeat the calculation in this
place.
The diameter of the plate is 31 inches, and the
length of the culhion 9 inches. Then 31.7854—-
31—18j1.7854=:522 fquare inches rubbed by one cu¬
lhion on one fide. And 512X4=2088 fquare inches
rubbed by the four culhions. Again, in the great ma¬
chine, the two plates having a diameter of 65 inches,
and eight culhions of 154 inches long, 65l2.7854—
65—31]2.7854= 2410.4. And I410 4x8=19283
fquare inches rubbed. But the intenfity of the eledtric
power of a machine will be in the compound ratio in-
verfely of the furfaces and number of turns when the
charge is the fame; Or 150X 2088 : 66x 19283 : : 1
— the intenfity of the larger machine ; 4= the inten¬
fity of the fmaller.
To have increafed the power of deady excitation
four-fold, is certainly an adonilhing acquifition. This
cxpreffion, however, of the intenfities appears to be lefs
generally ufeful than that of the ratio of the furface
rubbed, to that which is charged. This lad expreffion
becomes very fimple when the latter quantity is reduced
to 1, or unity. Thus, in the two machines here men¬
tioned, the rubbed furfaces in inches for the battery
19283X66 , 2088x150 ,. . .
fere —— , and , which are equal to
90X144 90X144
the fimple numbers 90.5 and 24.0, which refpeclively
denote the number of inches rubbed to charge one inch
of coated glafs.
From comparing the effedts of his awn machines in
the highed degree of excitation with thofe produced by
the great machine at Haarlem, Mr Nicholfon had been
induced to give the preference to the cylinder. From
later experience, however, and the account of the ef-
fedts produced by Van Marum’s new machine, Mr
Vol. VII. Part II.
*2$
Kate ma¬
chine pre¬
ferable to
a cylindri¬
cal.
E I C I T Y. 721
Nicholfon has been led to alter his opinion ; and he
now prefers a plate to a cylinder. illultrated
From confidering the defedts of the ufual methods of ^ eXper;.
edimating the power of machines, Mr Cuthbertlon ment.
was led to propofe the explofion of deer wire fes a pro-v——y——-^
per meafure; and he has made feveral experiments to 2.24
drew that this method is the lead liable to error. Mr jd ^
Nicholfon has given an account of thefe experiments in thoc} 0f
his Journal for Augud 1798 ; but they feem to require meafuring
a repetition and farther extenfion before they can be the power
received as conclulive. ^ chines.
As glafs j though preferable to all eledfrics that can ‘ 22$
be employed for the purpofes of excitation, from its Subftitutes
durability and unchangeable nature, is from its brittle-for glafs in
nefs attended with confiderable expence, various expe-
dients have been thought of to fubditute in its place 1
fome other eledlric in the condrudlion of eledtrical
machines.
Dr Ingenhoufz, the inventor of the plate machine,
made a variety of experiments for this purpoie. Pade-
board thoroughly dried and heated, and then foaked
and varnilhed with a folution of amber in linfeed oil,
formed plates which were drongly eledtrified when
rubbed with a cat’s Ikin or hare’s fkih. He tried baked
wood boiled in linfeed oil, but with lefs fuccefs. A
cylinder of drong filk velvet, formed by dretching that
fubdance upon two circular wooden dilks, was found
to afford confiderable eledlrical force when caufed to
revolve againd a culhion covered with hare’s Ikin *. * Phil.
And ladly, the fame philofopher contrived a portable Tranf. for
apparatus for charging a jar by means of a varnidred DTP*
filk ribband, expofed to the fri&ion of a rubber at¬
tached to the external coating, while the oppofite elec¬
tricity of the filk was taken ofi' by a metallic part com¬
municating with the infide.
It was at the beginning of 1784, that M. Walckiers
de St Amand undertook to condruft a machine, in
which a piece of filk was made to revolve inceffantly,
and pafs between two pair of rubbers. He made one
of fmall dimenfions, and afterwards a larger one, in
which the filk wTas twenty-five feet in length, and five
feet broad. In the following year M. Rouland, pro-1 Defcriptio*
feffor of natural philofophy in the univerfity of Paris, des machina
condructed a machine of the fame kindf. As the a
vantages and effects of thefe machines appear to Par
confiderable, we (hall here infert the defcription of the f^njRoU~
latter from Nicholfon’s Journal for December 1798. a\,6
A, B, fig. 80. is a wmoden table four feet and a half Defcription
long, tw7o feet nine inches wide, and fomewhat more °f a filk
than an inch and a half thick : its feet are 18 inches '
long. Upon this table are fadened by drong wooden clxxxIX.
fcrews, abed, twTo crofs pieces, each nine inches broad, js;0 2.
which carry the uprights C, D, E, F, which lad are 27
inches in height. Atabouttwm-thirdsormoreofthe height
of thefe uprights, there are cut notches of an inch fquare
each, in wdiich the axes of the two cylinders G and H
turn freely, Thefe axes are parallel to the table and to
each other, and are kept in their place by clamps of
wood ferewed over them. The cylinders G and H are
formed of light wTood glued together, and covered at
the ends by a circular piece, wkofe rounded edges arife
half an inch above the furface of the cylinders them-
felves. Their diameter is eight inches; the axes are of
box-wrood, and are lefs than an inch in diameter, hav¬
ing a ftioulder which prevents the ends of the cylinders
4 Y from
722 ELECT
Pnncip'es of from touching the uprights when turned round j and
Kkilncity laltly, the cylinders are covered with ferpe.
iHuftratea i .
by experi- 1 he haudIe 13 copper, its radius being fix inches
menu lcng-
^—v   ^ K, L, is a piece of taffety covered with oily and re-
finous mattei, of the fame hind as is uled m hranee m
the conftrufition of air-balloons, which, M. Rouland
fays, renders the filk very elearical: the breadth of the
filk is nearly one inch lefs than the length of the cy¬
linders, and it is wrapped round them with its ends
fewed together.
The whole breadth of the filk is taken hold of or
pinched between two flattened tin tubes oppofite each
other at M, and two of the lame kind at N: thefe are
the rubbers, and may be made to prefs againfl: each
other, more or lefs ftrongly, by means of ferews. They
are retained by firings of filk fallened to the four up¬
rights of the machine, v v are two brafs chains hook¬
ed upon the rubbers, and communicating with the earth 5
op and q r are four pieces of taffety, prepared in the
fame manner as the principal piece, fewed in the direc¬
tion of their length to the rubbers, and fallened to
each other by their correfponding comers by means of
threads of filk. J he metallic tubes or rubbers are co¬
vered with cat’s fkin.
S reprefents the conductor. It is a cylinder of brafs
three inches in diameter, 36 'inches in length, including
the balls at the end, -whofe diameters are four inches :
one of thefe balls has a ring, t, above it, which ferves
to form a communication between the condudlor S and
any other conduftor.
The upper and lower parts of this cylindrical prime
conduftor are armed with two plates of brafs y ?/, wdrofe
length is equal and correfpondent to the breadth of the
taftety, which is 26 inches, and 132 inches or 11 feet
long : the edges of the plates are about half an inch
dill ant from the filk, and ferve inllead of the metallic
points that were ufed by M. Walckiers, but rejedled
by M. Rouland, becaufe they were apt to flick into the
.filk and damage it.
The condudlot S is fufpended by filk firings, faflened
to the uprights of the machine by the hooks and rings
i i: its fituation is parallel to the cylinders G, H, and
equidiftant from each. The adlion of this machine is
as follows: The cylinder H is moved rapidly on its
axis by means of the handle, and the cylinder G moves
of courfe in the fame direction on the twm extremities
of its axis, provided the taffety K, L, be properly
ftretched. This tenfion is eafily obtained ; becaufe the
crofs pieces to which the uprights C, D, and E, F, are
fixed, may be moved nearer or further from each other,
and faftened by means of the ferews a b and c d, wdiich
pafs through holes cut in the diredlion of the table.
The rotation of the cylinders neceffarily producing
a circulation of the taffety, it muft confequently be
rubbed in its paffage between the tin tubes covered
with cat’s fkin at M and N j and by this fridlion it ob¬
tains what is called the negative eledlricity, which is
communicated from both parts of the filk to the com¬
mon condudlor S. But it may be made to eledlrify
pofitively, by removing the rubbers to the middle of
the filk, fo that the prime condudlor may communicate
with them : or, if the two cufhions be removed to half
the diftance .between the revolving cylinders and the
prime conductor, pofitive and negative electricity may
R I C I T Y. _ Part III.
be had at the fame time, the rubbers being in a nega-Principles of
txve ftate, and the prime conduftor in a pofitive ftate. Pk&ricity
J he advantages of a machine of this conftruftion d ultrated
beyond thofe of glafs are ftated by the inventor to be, ’ “'nienu *'
I. It is not brittle in any part. 2. Its excitation is ~
more fteady, becaufe it requires no amalgam. 3. Its
dimenfions have no limit.
I he power of excitation in this wTay appears to have
been very confiderable. The fadls are not related with
fo much detail as could be wifhed in the report of the
academy 5 but it appears that the negative fparks from
the conductor of Walckiers, which was five feet long,
veie from 15 to iy inches in length, very loud and
denfe, and very painful to the hand 5 that pointed bo¬
dies emitted very fenfible fparks to the condudor 5 and
that 2 battery of 30 fquare feet was charged by 30
turns of the machine, which gives 19 feet of filk rub- ’
bed to charge one foot of glafs *. In another inftance, * See Phil
however, it is faid, that a fquare foot w^as charged by Journal
one turn of the machine, which anfwered to 3 i-I-Iquare1, 87-
feet of filk. It is not faid wrhether the labour of turn¬
ing was confiderable or not.
M. Rouland made feveral trials to fubftitute plain
filk inffead of that which was varniflied j and he alfo
tried woollens and mixed cloth containing goat’s hair j
but none of thefe anfwered to his fatisfaclion.
Chap. XII. Of the Electric Properties of Air.
We have ranked air among the eledrics, but it will Heated afr
be feen by the table of eledric iubftances given in pagefaid to be a
646. that it is but an imperfed eledric. We have ob-conck|cl;or-
ferved at the beginning of this part, that it may even
become a condudor by being impregnated with moif-
ture. It is alfo found that when air is heated to a con¬
fiderable degree, it becomes a condudor; this accord-
ing to Cavallo, may be ftiewn by the following experi¬
ment. Eledrify a common ball eledrometer, or the
prime condudor with Henly’s quadrant eledrometer
placed upon it; the balls will, of courfe, feparate from
each other, or the index of the quadrant will denote
the degree of eledricity communicated to the prime
condudor. Now bring a red-hot iron within a fuffici-
ent diflance of the eledrometer or the prime condudor,
and it tvill be found that they foon lofe their eledricity,
it being conduded away by the heated air that fur-
rounds the iron •, that the heated iron is the caufe of
the lofs of eledricity may be proved, by repeating the ex¬
periment with the fame iron when cold, as in this cafe
it will be found that the eledfometer of the condudor,
will not lofe its eledricity fo foon, unlefs the iron be
brought very near.
Mr Read made the following experiment to prove
that hot air is not a condudor. ^
“It has been,” fays Mr Read, “ commonly’faid, This denied
that hot air conduds eledricity. With a view to af-by Mr
certain this matter, the following experiments were ^-ea<f
made. To one end of a long piece of wrood (which
ferved as a handle,) was fixed a glafs rod fifteen inches
long j to the remote end of the glafs was fixed a pith-.
ball eledrometer. Having eledrified the balls, I held
them by the wood handle, and projeded them into a
large oven, immediately after the fire was draw n out of
it; the confequence wras, that wEen I performed the
operation flowly, the balls loll their eledricity 3 but
% R tad's
Jummary
’view of
fpontancous
eleilricity.
229
Means of
exciting
air.
230
Friction.
Chap. XII. ELECT
Principles of that when done quick, with as little delay as poffible.
Electricity eleftric charge was not ditninilhed. The lofs ol
Htufl:rated [n t}^ firft Cafe, was found to have efcaped
^ment. along the glafs into the wooden handle, and fo to the
u—y ■■ ' earth, owing to the great heat the glafs rod had acquir¬
ed, by which it became a condudfor of the fluid j for
until it had cooled a little, the balls could not be char¬
ged again.
“ I lhall lay before the reader one circumftance more,
becaufe it may tend to throw light on what degree of
heat the oven was in at the time the oblervations were
made. The baker having pointed out to me the hot¬
ted part of the oven with a quick motion in and out,
I plunged the electrified balls into that part of it, by
which one thread ball was burned off, but the remain¬
ing ball (hewed that it ftill retained its eleftric charge,
becaufe it was ftrongly attracted on the approach of my
finger *.
Air, as an ele&ric, may be eleftrified either by ex~
citation or by cojntnunication.
Air may be excited by any circumftance which tends
to produce motion among its particles; as by friction,
evaporation, heat and cold, expanfion and contraction,
and by any chemical proceffes in which thefe circum-
Itances are produced.
1. That air may be excited by fridtion was fuflicient-
ly fhown by the experiments related to demonftrate the
fenfibility of Bennet’s eledtrometer ; by thefe experi¬
ments it appeared, that whenever a cloud of duft or
powder was raifed in the air furrounding the electrome¬
ter, the flips of gold leaf, by their feparation, manifeited
figns of eleCtricity, which muff doubtlefs have been
produced by the attraction of the particles of duft or
powder againft the particles of air.
2. Air may be rendered eleCtrical by the vapour or
fmoke which rifes into it from evaporating or burning
fubftances. At the end of the firft part of this article,
we noticed, in a general way, Sig. Volta’s experiments
on the eleCtricity produced by evaporation ; we mult
now confider this lubjeCt rather more at large, t he
produCtion of eleCtricity by evaporation, may be ftiown
by the following experiments.
Exper. I. Upon the cap of Bennet’s eleCtrometer <r,
fig. 81. place a metallic cup containing a little water j
drop into the water a red-hot coal, or a red-hot piece
of clean iron \ a vapour will arife from the water, and
the (trips of gold leaf n n will diverge with ftrong ne¬
gative eleCtricity. If at the fame time, an iron wire/>,
fixed to a rod of glafs or fealing-wax, with a common
ball eleCtrometer hanging from its extremity, be held
by the glafs or fealing-wax in the air, at a little dif-
tance above the cup, the balls d will be found to di¬
verge with pofitive eleCtricity.
Exper. 2. Let there be two of the above electrome¬
ters, as A, B, fig. 8 2.; upon the cap of the eleCtrometer
B, place a metallic cup d, as in the laft experiment,
and into the cap of the eleCtrometer A, let there be
ferewed a bent wire m, with a piece of tin s foldered
to its other extremity. If now, the eleCtrometer B
with its metallic cup be placed immediately below the
tin r, and a cullender c, containing a few live coals,
be held over the cup, and if water be poured frdm the
jug upon the coals in the cullender, fo as to fall into
the metal cup, the flips of gold lea/ in both electrome¬
ters will diverge; thofe of the electrometer B, with
Evapora¬
tion.
Plate
CXCI.
R I C I T Y. 723
negative eleCtricity, and thofe of the eleCtrometer Aj^dacipleso'
with pofitive deftricity, flhfaaS
I he experiments on the eleCtricity produced by eva- ^ eXpen-
poration, may be very conveniently made by heating ment.
the frnall end of a pretty long tobacco-pipe, and pour- * 1
ing water into the bowl of it j the water rtinning down
to the heated part, which (hould be held over the cap
of Bennet’s eleCtrometer, is fuddenly expanded into va¬
pour, and the flips of gold leaf wall feparate with nega¬
tive eleCtricity, 232
In the above experiment it has been feen, that theTTeelec-
eleCtrometer from which the vapour arofe, was alwaystriclty 77°
eleCtrified negatively ; from having obferved this to be1)0[jies n0^
always the cafe in his experiments, Sig. M, Volta always ne-
confidered it as a general law. Mr Cavallo, however,gative. „
mentions fome experiments made by a profefior at Man¬
tua, and by himfelf, which feem to contradict this fup-
pefition.
All the experiments, (fays Mr Cavallo), made on
evaporation for fome years after this difeovery, were at¬
tended with refults conformable to the above-meutioned
general law ; but two remarkable exceptions have of
late been diicovered, which, befides their contradict¬
ing the faid law, feem to point out a more intimate
connection between the eleCtric fluid and other bodies.
The firft of thofe exceptions was difeovered and pub-
liihed three years ago, by a learned profeffor of the
academy of Mantua; the fecond was very lately dif¬
eovered by myfelf.
The Mantuan profeffor obferved, that when water
was evaporated by being put in contaCt with a red hot-
piece of rutty iron, it would leave the iron eleCtrified
politively j whereas when the experiment was tried wdth
a clean piece of iron, the eleCtricity acquired by the
metal would be of the negative kind.
When I firft attempted to repeat this curious experi¬
ment, the refult did by no means anfwer my expecta¬
tions ; the eleCtricity, which was produced being of
the negative, and not of the pofitive kind but obferv-
ing that fometimes no fenfible degree of eleCtricity was
produced, though the evaporation was very quick and
copious, I began to fufpeCt that the iron, which I had
employed, was not fufliciently covered with ruft, in
Confequence of which two oppofite dates of electricity
might poflibly be produced, viz. the negative from the
clean, and the pofitive from the rufty part of the iron :
which two oppofite dates, by counteracting each other,
would leave the iron un-eleCtrified. Afrer various re¬
petitions of this experiment, in which the red-hot iron
was thrown into the infulated water, or the wrater wyas
poured upon the red-hot and infulated iron, I found
that this wras aftually the cafe.
I procured fome old iron nails, which had remained
expofed to the atmofphere for feveral years, and of
courfe had contracted a very thick coat of ruft ; and on
performing the experiment with them, I obtained pofi¬
tive eleCtricity, agreeably to the affertion of the above-
mentioned gentleman. The fame nail very feldom
wrould anfwer for more than one experiment j for the
aCtion of the fire and of the wTater generally removed a
great deal cf the ruft, and exhibited the naked metal,
w hich would afterwards acquire the negative eleCtricity.
Here follows the manner of performing this remarkable
experiment.
Jnfulate a metallic or earthen plate^ and pour a
4 Y 2 fm^ll
724 ELECT
Principles offmall quantity of water in it, and let a fenfible eleftro-
iiiuftn'ted meter be connefted with the w^ater j then drop a red-hot
by 'experi- Piece iron ^0 the plate, and it wall be found, that,
ment. . if very rufty iron be ufed, the eleflrometer vdll be
' v 1 opened with pofitive eleftricity ; if the iron be clean,
or free from ruft, the electrometer will acquire the ne¬
gative eleftricity j and laitly, if the iron be partially
nifty, the electrometer will acquire little or no eleCtri-
city, though in every cafe the evaporation may be equal¬
ly quick and copious.
The other exception of the above-mentioned general
law is ftiown by means of red-hot glafs, which I chan¬
ced to difcover very lately. The various degrees of
eleCtric power that are produced by the evaporation of
w^ater from different fubftances induced me to diverfify
the experiments as much as I could, in order to dif¬
cover, if poflible, the reafon why thofe different effeCls
took place when the evaporation feemed to be equally
quick and copious. Amongft other fubftances, I tried
glafs, and found that it generally produced little or no
, eleClricity. The wyater was fometimes poured upon the
hot glafs, but in general the hot glafs was dropped into
the infulated water, which was contained in a tin cup.
However, the difference of effeCt was found not to be
occafioned by thofe two different modes of proceeding.
Having repeated this experiment a great many times, I
at laft found, that the effeCl depended on the different
nature of the glafs. If white and clean flint glafs be
made red-hot, and in that ftate be dropped into the vef-
fel of water, a quick evaporation will enfue, and the
veffel is eleftrified pofitively. If the flint glafs be not
very clear, there will not be any ele&ricity generated
by the evaporation, &c. And laftly, if the experi¬
ment be tried with more impure glafs, as the glafs of
which wine bottles are made, the negative electricity
will be produced.
In performing this experiment, it is neceffary to take
care that no pieces of coal adhere to the glafs, which
will frequently happen when a piece of glafs is heated
in a common fire ; for in that cafe negative electricity
will be produced by the evaporation, though the belt
flint glafs be ufed.
It has frequently happened, in the courfe of my ex¬
periments, that no eleClricity whatever has been pro¬
duced by the evaporation of water from certain fubftan¬
ces ; however, as in thofe cafes the evaporation w7as
not very copious, I attributed the deficiency of eleCtri-
eity to the weaknefs of the evaporation. But a very
remarkable inftance of this fort is mentioned in the dif
fertation of the above-mentioned ingenious profeffor.
He flaked 25 pounds weight of quicklime with a fuf-
ficient quantity of -water, and though a very -copious
evaporation took place, yet it was not attended with
any eleClricity. Should any perfon fufpeCt, that the
deficiency of eleftricity in this experiment wras owing
to the w7ant of burning coals or aCtual fire, he fhould
confider, that in other fimilar proceffes eleClricity is
. produced without any aClual fire ; thus the evaporation,
which is occafioned by the effervefcence of iron filings
in diluted vitriolic acid, produces negative eleClricity.
After a careful examination of the above-mentioned
experiments, the origin of the eleClricity, which is ob-
ferved in the- evaporation of wTater and other evaporable
fubftances, wdiether folid or fluid, feems not to be re-
eoncileable to the general lavr already noticed;, nor can
R I C,I,T Y- Part m
I form any plaufible theory that can be fufficient to ac- Principles of
count for all the phenomena. If the production of E^dhicity
eleClricity in thofe experiments depended upon the in- illuftratecl
creafed or dimmifiied capacity of water for holding the
eleCtric fluid, it thould feem to be immaterial whether ^
the wrater be evaporated in one way or in another, pro¬
vided the evaporation be made with equal quicknefs
and in equal quantities. Were it not known that glafs
or iron made red-hot produces no eleClricity in cooling,
we might fufpeCt, that the eleClricity, which is produ¬
ced by the evaporation of water, may be counteracted
by the contrary eleClricity, which is produced by the
cooling of glafs or iron ; but it has been obferved by
feveral ingenious perfons, that red-hot glafs and red-
hot iron produce no eleClricity whatever when fuffered
to cool upon infulated Hands.
It has been found that eleClricity promotes eva¬
poration. This may be proved by the following
Exper. Upon the prime conductor of an eleftrical Evapora-
machine, place a fhallow metallic difti, as a pewter tion increaf-
plate, containing a fmall quantity of w7ater ; and let a ec! ele(>
fimilar difh, containing fuch a quantity of water as thattncity
the two difties may exaCtly counterpoise each other, be
placed on a table at a diftance from the machine. Now
fet the machine in motion, and after a certain time has
elapfed, place the two difties again in the Scales, and it
will be found that the difti which flood on the prime
conduClor is lighter than the other ; evidently fhowing
that more of the water has been evaporated.
This experiment might with more propriety have
been given when defcribing the chemical effeCts of the
eleCtric power.
We ftiall return to this fubjeCt, under Attnofpherical
EleBricity, to which the consideration of the other cir-
cumftances effecting the eleClricity of air by excitation,
more properly belongs.
Air may be eleCtrified by communication in two Method of
ways j by Jimp/e electrification, as it is called, or by electrifying
charging a ftratum of it fituated between tw7o conduCt-t!ie air of *
ing furfaces. room.
Exper. 1.—Fix twm or three pointed needles into
the prime conductor of an eleCtrical machine, and fet
the glafs in motion fo as to keep the prime conductor
eleClrified for feveral minutes. If now7, an eleClrometer
be brought within the air that is contiguous to the
prime conductor, it will exhibit Signs of eleClricity, and
this air will continue eleCtrified for fome time, even af¬
ter the machine has been removed into another roem.
The air, in this cafe, is eleClrified pofitively ; it may
be negatively eleClrified by fixing the needles in the ne¬
gative condudor while infulated, and making a com¬
munication between the prime conductor and the
table, by means of a chain or other conducting fubftance.
The air of a room may be eleCtrified in another way.
Charge a large jar, and infulate it 5 then conneCt two
or more {harp pointed wires or needles, with the knob
of the jar, and conneCt the^outfide coating of the jar with
the table. If the jar be charged pofitively, the air of
the room will foon become pofitively eleClrified likewife;
but if the jar be charged negatively, the eleClricity com¬
municated by it to the air, will become alfo negative.
A charged jar being held in one hand, and the flame
of an infulated candle, held in the other, being brought
near the knob of the jar, will alfo produce the fame ef¬
feCl.
A
Chap. XII. / E L E C T R
Principles of A ftratum of air may be charged in the fame man-
Elearicity ner as a plate of glafs, when its oppofite lurfaces are
illuitrated laceci contaft with metallic plates which ferve as a
hYment.n' coating to the plate of air. ■ i u A
.  1 Xo perform this experiment, take two circular boards,
23 s each three or four feet in diameter, made perfectly
Method of fmooth^ and their edges rounded } coat one fide of each
charging a board ^ tinf0n? fo that it may be turned up over
plate or air.^ edge of the boardj and let it be burnifhed fo as to
render it as fmooth as poffible. Ihefe boards mutt be
placed, with their coated fides parallel to each other,
horizontally, and fo that they may be fet at a greater
or fmaller diftance, and they muft both be mfulated.
For this purpofe, it is moll convenient to fix one of the
boards on a ftrong fupport of glafs or baked wood, and
to fufpend the other by filken firings from the ceiling
of the room, from which it may be raifed or lowered
by a proper pulley, fo as to be placed at the required
diftance from the lower board.
The boards being thus placed in their fituation, at
the diftance of about an inch from each other, on their
being cleft rifled, the ftratum of air, interpofed between
them, will prefent phenomena fimilar to thofe of a
plate of glafs under the fame circumftances. On con-
nefting one of the boards with the prime conduftor,
while the other is infulated, the air will receive no
charge agreeably to what wras remarked of an infulated
Leyden phial. But if, while one of the boards is elec¬
trified from the prime conduftor, the other be made to
communicate with the earth or other condufting bodies,
the plate of air will receive a charge, and when the
communication between the boards is completed by
conduftors, an explofion will take place. Ihe explo-
fion in this cafe, however, is by no means fo remarkable
as that which is produced from an equal furface of
coated glafs, for reafons winch will be explained here¬
after. .
The experiment of charging a plate of air was fiift
made by M. iEpinus and M. Wilcke, who being at
r Berlin together, jointly made feveral experiments. ^
This'expe- They made feveral experiments to give the eleftnc
rimer.t firft fliock by means of air, and at length iucceeded by fuf-
made by pending large boards of wTood covered with tin with toe
^pinus flat fides parallel to one another, and at fome inches
and Wilcke. afunder. for tbey found, that upon eleftrifying one of
the boards pofitively, the other wras always negative.
But the difcovery wTas made complete and indifputable
by a perfon touching one of the plates with one hand,
and bringing his other hand to the other plate ; for he
then received a fhock through his body, exaftly like
that of the Leyden experiment.
With this plate of air, they made a variety of curi¬
ous experiments. The two metal plates, being in op¬
pofite ftates, ftrongly attrafted each other, and w'ould
have rulhed together, if they had not been kept afun¬
der by firings. Sometimes the eleftricity of both
wmuld be discharged by a ftrong fpark between them,
as when a pane of glafs burfts with too great a_ charge.
A finger put between them promoted the difcharge,
and felt the (hock. If an eminence was made on either
of the plates, the felf difcharge would always be made
through it, and a pointed body fixed upon either of
* them prevented their being charged at all *.
'Tentamen. At the end of the table of conductors given in page
646. it was obferved that a Torricellianjacuum was a
I C I T Y. 725
non-conduftor of eleftricity. Some experiments tvere Pnncipies ot
made by Mr Walfti, which proved the perfeft imper-
meability of a vacuum by the eleftric light. But the by'experi-
moft complete experiments on this fubjeft are thofe of meat.
Mr W. Morgan and Mr Cavallo. The following are ' v ’
Mr Morgan’s experiments. 237
A mercurial gage B, fig. 83. about 15 inches long,MrMoi;-
carefully and accurately boiled, till every particle of air
was expelled from the infide, w’as coated with tin-foil, non_
five inches down from its fealed end (A), and being in-con(julqing
verted into mercury through a perforation D, in the power of a.
brafs cap E, which covered the mouth of the ciftern perfect v*.-
H ; the wdiole was cemented together, and the air was cuum-
exhaufted from the infide of the ciftern through a valve
C, in the brafs cap E juft mentioned 5 which producing
a perfeft vacuum in the gage B, afforded an inftrument
peculiarly wTell adapted for experiments of this kind.
Things being thus adjufted, a fmall wire, F, having
been previoufly fixed on the infide of the ciftern, to
form a communication betwTeen the brafs cap E, and
the mercury G, into which the gage was inverted } the
coated end A was applied to the conduftor of an elec¬
trical machine ; and, notwithftanding every effort, nei¬
ther the fmalleft ray of light, nor the flighteft charge,
could ever be procured in this exhaufted gage. It is.
w'ell known, that if a glafs tube be exhaufted by an
air-pump, and coated on the outfide, both light and a-
charge may very readily be procured. If the mercury
in the gage be imperfeftly boiled, the experiment will
not fucceed ; but the colour of the eleftric .light, which,
in air rarefied by an exhaufter, is always violet or pur¬
ple, appears in this cafe of a beautiful green 5 and what
is very curious, the degree of the air’s rarefaftion may
be nearly determined by this means. There have been
inftances known, in a cour.fe of experiments, where a
fmall particle of air having found its way into the tube
B, the eleftric light became vifible, and as ufual of a
green colour } but the charge being often repeated, the
gage has at length cracked at its fealed end, and in cotv.
fequence the external air, by being admitted into the
infide, has gradually produced a change in the eleftric
light, from green to blue, from blue to indigo, and fo
on to violet and purple, till the medium has at laft be¬
come lo denfe, as no longer to be a conduftor of elec¬
tricity. There can be little doubt, from the above ex¬
periments, of the non-condufting power of a perfeft
vacuum ; and this faft is ftill more ftrongly confirmed
by the phenomena which appear upon the admiftion of
a very minute particle of air into the infide of the gage.
In this cafe, the whole becomes immediately luminous,
upon the flighteft application of eleftricity, and a charge
takes place, which continues to grow more and more
powerful, in prop6rtion as frelh air is admitted, till the
denfity of the condufting medium arrives at its maxi¬
mum, which it always does when the colour of the elec¬
tric light is indigo or violet. Under thefe circumftances,
the charge may be fo far increafed, as frequently to
break the glafs. In fome tubes, which have not been
completely boiled, they will not conduft the eleftric
fluid, when the mercury is fallen very low in them *,
yet upon letting in air into the ciftern H, fa that the
mercury ftiall rife in the gage B, the eleftricity, which
was before latent in the infide, fliall now become vifible,
and as the mercury continues to rife, and of confe-
quence the medium is rendered lefs rare, the light fliall
grow
72<5 E L E C T
^iiriIl le:StofgrOW more and m.ore vIflb1^ and the gage fliall at laft
‘^‘7 Ije charged, notwithftandiny it has not heen nn
ment.
Surprifing
eafe with
which an
exhaufted
tube may
tricity.
lluhratcd e c'uarSei^ notwithftanding it has not been near an
by experi- machine for two or three days. 1'his feems
to prove, that there is a limit, even in the rarefaction of
ait, which fets bounds to its conducting power j or, in
other words, that the particles of air may be fo far’ fe-
parated from each other, as no longer to be able to
tranlink the eleCtricity-j that if they are brought within
a ceitain diltance of each other, their conducing power
begins,_ and continually increafes, till their approach
alio arrives at its limit, when the particles again become
fo ncai, as to relift the paffage of the electricity entire¬
ly, without employing violence, which is the cafe in
common and condenfed air, but more particularly in the
latter.
It is furpriling to obferve, how readily an exhaufted
tube is charged with eleftricity. By placing it at ten
or twelve inches from the conduftor, the light may be
 , feen pervading its infide, and as ftrong a charge may
be charged fometimes be procured, as if it were in contaft with the
with elec- conduftor. Nor does it fignify how narrow the bore of
the glafs may be 5 for even a thermometer tube, having
the minuteft perforation poflibie, will charge with the ut-
moft facility; and in this experiment, the phenomena are
peculiarly beautiful.
Let one end of a thermometer tube be fealed herme¬
tically 5 let the other end be cemented into a brafs cap
with a valve, or into a brafs cock, fo that it may be
fitted to the plate of an air-pump. When it is exhauft¬
ed, let the fealed end be applied to the conduftor of an
eleCtrical machine, while the other end is either held in
the hand, or connected to the floor. Upon the flighteft
excitation, the eleCtricity will accumulate at the fealed
end, and be difcharged through the infide in the form
of a fpark 5 and this accumulation and difcharge may
be incefiantly repeated, till the tube is broken. By this
means, a fpark 42 inches long may be procured ; and
if a proper tube could be found, we might have a fpark
three or four times that length : if, inftead of the fealed
end, a bulb be blown at that extremity of the tube, the
eleCIric light will fill the whole of that bulb, and then
pafs through the tube in the form of a brilliant fpark, as
m the foregoing experiment; though in this cafe, the
charge, after a few trials, will make a fmall perforation
in the bulb. If, again, a thermometer, filled with mer¬
cury, be inverted into a ciftern, and the air exhaufted
in the manner before defcribed for making the experi¬
ment with the gage, a Torricellian vacuum will be pro¬
duced ; and now the eleCIric light in the bulb, as well
as the fpark in the tube, wdll be of a vivid green ; but
the bulb will not bear a frequent repetition of charges,
before it is perforated in like manner as when it has been
exhaufted by an air-pump. It can hardly be neceffary
to pbferve, that in thefe cafes the eleCIricity affumes the
appearance of a fpark, (f) from the narrownefs of the
paffage through which it forces its way. If a tube, 40
inches long, be fixed into a globe eight or nine inches in
diameter, and the whole be exhaufted, the eleCiricitv,
after pafling in the form of a brilliant fpark throughout
the length of the tube, will, when it gets into the in-
R I C I T Y. PartlH.
, £1°: t1a<r expand itfelf in all direCIions, entire-Principles of
ly filling it with a violet and purple light, and exhibit- Electricity
ing a linking inltance of the vail elafticity of the elec- lUuftrated
trie power. by
Mr Morgan concludes his remarks with acknow-
ledging his. obligations to Mr Brooke of Norwdch
for communicating to him his method of making mer¬
curial gages.
Mr Brooke’s method of making mercurial gages is Mr2"39
nearly as follows: Let a glafs tube L (fig. 84.), lealed ttrooke’s
Hermetically at one end, be bent into a right angle with-naetbod °^
in two or three inches of the other end. At the diltance making. ,
of about an inch or lefs from the angle, let a bulb K, oCZl"™'
about three-fourths of an inch in diameter, be blown m * ’
the curved endr and let the remainder of this part of the
tube be drawm out /, fo as to be fufticiently lono- to take
hold of when the mercury is boiling. The bulb K is
defigned as a receptacle for the mercury, to prevent its
boiling, over j and the bent figure of the tube is adapt¬
ed for its inverfion into the ciftern : for by breaking off
the tube at M within an eighth or a fourth part of an
inch of the angle, the open end of the gage may be
held perpendicular to the horizon when it is dipped in-
to.the mercury in the ciftem, without obliging us to
bring our finger or any other fubftance into contaft with
the mercury in the gage, which never fails to render the
inftrument imperfea. It is neceffary to obferve, that if
the tube be 14 or 15 inches long, it will be impoflible
to boil it effectually lor the experiments mentioned a-
bove in lefs than three or four hours, although Mr Brooke
feems to preferibe a much fliorter time for the purpofe 5
nor will it. even then fucceed, unlefs the greateft attend
tion be paid that no bubbles of air lurk behind, which
is frequently the cafe : but experience has taught how
to guard pretty well againft this difappointment, parti¬
cularly by taking care that the tube be completely dry
before the mercury is put into it; forif this caution be not
obferve.d, the inftrument can never be made perfea.
There is, however, one evil which it is fufficient to re¬
medy ; and that is, the introduaion of air into the gage,
owing to the unboiled mercury in the ciftern : for when
the. gage has been a few times exhaufted, the mercury
which originally filled it becomes mixed with that into
which it is inverted, and in confequence the vacuum is
rendered lefs and lefs perfea, till at laft the inftrument
is entirely fpoiled.
Mr Cavallo’s experiments were made with an excel¬
lent air-pump, which is defcribed in the 73d volume of
the Philofophical TranfaCtions.
I he following is the refult of Mr Cavallo’s experi -2d°
ments as given by himfelf. 1 , ,r CaVjI"
brom thefe experiments it appears, firft, that in ments on
the utmoft rarefaaion that can be effeaed by the befttbe fame
air-pump, which amounts to about one thoufand, both fubje<a-
the dearie light, and the dearie attraaion, though
very weak, are ftill obfervable ; but, fecondly, that the
attraaion and repulfion of efearicity become weaker
in proportion as the air is more rarefied, and in the
fame manner the intenlity of the light is gradually di-
minilhed. Now, by reafening on this analogy, we may
conclude
* one ei,d °f a ti'ermomcto tute’a fpark t be °bts“'d>»"di
Chap. XIII. ELECT
Principles cfconclude, that both the attraction and the light will-
El'-chicity ceafe in a perfect abfence of air 5 but* this will never
iljurttavc, accounl; for this perfect vacuum ever becoming a non-
^ment. conductor of eletricity j however, the fact feems to be
t.. ■-v— . fully afcertained by Mr Wallh and Mr Morgan, and
the only thing that remains to be done is to invelligaie
the caufe of fo remarkable a property.”
Experiments on the action of electrics in vacuo had
been long ago made by Mr Boyle and Mr Gray 5 but
as the vacuum that they were able to produce was very
imperfect, it is not furprifing that they could perceive
no difFerence whether the body was expofed in the open
air or confined within an exhaufled receiver.
1
Chap. XIII. Of the means of afcertaining fmall de¬
grees of Electricity.
241
Ufual elec- lx the courfe of this part of our ar icle we have al-
troll|.e^rs ready defcribed many inftruments for afcertaining the
cKutiy de Pre^ence °f electricity ; and one of thefe, Bonnet's E/cc-
hcate for tromeler, has been fhewn to be exceedingly fenfible.
nice obftr- But on a nicer examination it has been found, that in
tcons. the courfe of experiments, as well as in obfervations on
natural eletricity to be related hereafter, the quantity
or degree of eletricity is fo minute, as not to be fenfi¬
ble by means even of this delicate inftrument, and is
yet capable of being rendered fufficiently obvious by
other means. Thefe means we are now to defcribe.
Moft of the means which have been devifed for
rendering fenfible minute degrees of eletricity have
242 been fuggefted by the effets of Volta’s eletrophorus.
Method of The firfl procefs employed for this purpofe was in-
ber^ard vented by Profelfor Lichtenberg, and the fame thought
-Klincock. ^e€ms to have occurred to Dr Klincock of Prague.
It was performed by means of two refinous plates like
thofe of the common eletrophorus, and one metallic
plate with an infulating handle. One of the refinous
plates wras firfl excited by flight frition, and it was
then employed to communicate eletricity to the me¬
tallic plate, which wTas in its turn made to communi¬
cate eletricity to the other refinous plate. The elec¬
tricity poflefled by this latter plate w7as now com¬
municated to the metallic plate : this was again con¬
veyed to the firfl refinous plate, of which it increafed
the eletricity by communication. By repeatedly ap¬
plying the metallic plate to each of the refinous plates,
"^W^for 1V]'t^out bringing them in contat, the eletricity at firfl
Z?8o”‘ °r excited wns accumulated till it became fufficiently
' 243 fenfible to an ordinary eletrometer *.
Experi- The next method employed was that of the cele-
v H ^ 1 d kratecl Volta, or the condenfer. But before we de-
to the in- ^cr^be the apparatus and the mode of ufing it, it is
vention of necelfary that w7e ffiould give a brief account of the ex-
Volta’s periments which led to the invention,
condenfer. Mr Volta found that conduflors of the fame fltape
loTduaorfWCre caPa^e °f containing more or lefs eledlricity, as
' their furfaces are /f or more influenced by homologous
atmofpheres; and that the capacity of a conductor of
the fame ffiape and furface w7as increafed, when, inflead
of being quite inflated, they were, while infulated, pre-
fented to another conductor not infulated, and this in-
creafe became more confpicuous according as the twro
condudlors were larger, or approached nearer to each
other.
R I C I T Y
’27
When an infulated conduftor is thus prefentcd to Principles of
any other conduflor, Signior Volta calls it a Conjugate Electricity
Conductor. ^ ^
In order to fhew by experiment the above-mention- mpnt.
ed property or increafe of capacity in a conduflor, take ’ v~—
the metal plate of an electrophcrus, and holding it by 2.44
its infulating handle in the air, electrify it fo high,
that the index of an electrometer annexed to it might
be elevated to 6o°; then lowering this metal plate by
degrees towrards a table or other conducting plain fur-
face, you wall obferve that the index of the electrome¬
ter will fall gradually from 6o° to 50°, 40°, 30°, &c. >
Notwithllanding this appearance, the quantity of elec¬
tricity in the plate remains the fame, except the faid
plate be brought fo near the table as to occafion a
tranfmiffion of the electricity from the former to the
latter ; at lead the quantity of electricity will remain
as mu'di the fame as the dampnefs of the air, &c. will
permit. The decreafe, therefore, of intenfity is owing
to the increafed capacity of the plate, which is now con¬
jugate, viz. oppofed to another condudling furface. In
proof of which, remove gradually the metal plate from
the table, and it will be found that the electrometer
rifes again to its former ilation, namely to 6o°, except¬
ing the lofs of that quantity of eleftricity, which du¬
ring the experiment mull have been imparted to the
air.
The two following experiments will throw more
light upon the reciprocal aftion of the eledlric atmo¬
fpheres. Fir ft, fuppofe two flat conductors, eleCtrified
both pofitively or both negatively, to be prefented to¬
wards, and to be gradually brought near, each other 5
it will appear by two annexed electrometers, that the
nearer thofe two conductors come to each other, the
more their intenfities will increafe; which ftiews, that
either of the two conjugate conductors has a much lefs
capacity now, than when it was fingly infulated, and
out of the influence of the other.
Secondly, let the preceding experiment be repeated,
with this variation only, viz. that one of the flat con¬
ductors be eleCtrified pofitively, and the other negative¬
ly : the effeCts then will be juft the reverfe of the pre¬
ceding 5 viz. the intenfities of their eleCtricities wall
be diminiftied, becaufe their capacities are increafed,
the nearer the conductors come to each other.
Let us now apply the explanation of this laft expe¬
riment to that of bringing an eleCtrified metal plate to¬
wards an uninfulated conducting plane; for as this
plane acquires a contrary eleCtricity by the vicinity of
the eleCtrified plate, it follows that the intenfity of the
eleCtricity of the metal plate muft be diminiffied, and
in the fame proportion its capacity is increafed ; con-
fequently the metal plate in that cafe may receive a
greater quantity of eleCtricity.
This property may be rendered ftill more evident, by
infulating the conducting plane wffiilft the eleCtrified
plate is very near it, and afterwards feparating them ;
for then both the metal plate and the conducting plane
(Trhich may be called the inferior plane) will be
found eleCtrified, but poffeffed of contrary eleCtricities,
as may be afcertained by electrometers.
If the inferior plane be infulated firft, and then the
eleCtrified^plate be brought over it, then the latter will
caufe an endeavour in the former to acquire a contrary
eleCtricity, which however the infulation prevents from
taking
ELEC T
Principles of taking place j hence the intenfity of the eleftricity of
n I art rated t^.e hlate is 110t diminiOied, at lead the electrometer
by experi- vv^ Ihew a very little and almoft imperceptible depref-
ment. hon, tvhich is owing to the imperfection of the infula-
1*" v " tion of the inferior plane, and to the Imall rarefadtion
and condenfation of the dearie fluid, which may take'
place, in different parts of the faid inferior plane.
But if in this fituation the inferior plane be touch¬
ed, fo as to cut off the infulation for a moment,
then it will immediately acquire the contrary ekari-
city, and the intenfity in the metal plate wall be dimi-
nilhed.
If the inferior plane, inftead of being infulated, were
itfelf a non-conduaing fubftance, then the fame pheno¬
mena would happen, viz. the intenfity of the ekarified
metal plate laid upon it would not be diminilhed.
This, however, is not ahvays the cafe ; for if the faid
inferior non-conduairtg plane be very thin, and be laid
upon a conduaor, then the intenfity of the ekarified
metal plate will be diminilhed, and its capacity will be
increafed by being laid upon the thin infulating ftra-
tum, becaufe, in that cafe, the conduaing fubftance
which Hands under the non-conduaing ftratum ac¬
quiring an ekaricity contrary to that of the metal
plate, will dimini Hi its intenfity, &c. and the infulating
ftratum will only diminilh the mutual aaion of the
two atmofpheres, more or lefs, according as it keeps
them more or lefs afunder.
The intenfity or ekaric aaion of the metal plate,
which diminifties gradually as it is brought nearer and
nearer to a conduaing plane not infulated, becomes al¬
moft nothing w7hen the plate is nearly in contaa with
the plane, the compenfation or accidental balance be¬
ing then almoft perfea j hence if the inferior plane
only oppofes a fmall refiftance to the paffage of the
ekaricity (whether fuch refiftance be occafioned by a
thin ekaric ftratum, or by the plane’s imperfea con¬
duaing nature, as is the cafe with dry wood, marble,
&c.) that refiftance, and the interval, however fmall,
that is between the tw7o planes, cannot be overcome
by the w7eak intenfity of the ekaricity of the metal
plate, which on that account will not dart any fpark
to the inferior plane (except its ekaricity were very
powerful, or its edges not w7ell rounded) and will
rather retain its ekaricity ; fb that, being removed
from the inferior plane, its ekarometer will nearly re¬
cover its former height. Befides, the ekarified plate
may even come to touch the imperfeaiy conduaing
plane, and may remain in that fituation for fome time :
in wdiich cafe the intenfity being reduced almoft to
nothing, the ekarieity wall pafs to the inferior plane
exceedingly flowly.
But the cafe will not be the fame, if, in performing
the experiment, the ekarified metal plate be made to
touch the inferior plane edgewife } for then its intenfi¬
ty being greater than w’hen laid flat, as it appears by
the ekarometer, the ekaricity eafily overcomes the
fmall refiftance, and paffes to the inferior plane, even
acrofs a thin ekaric ftratum ; becaufe the ekaricity
of one plane is balanced by that of the other, only in
proportion to the quantity of furface which they op-
pofe to each other wdthin a given diftance 5 whereby,
when the metal plate touches the other plane in flat
and ample contaa, its ekaricity is not diflipated.
Hitherto wx have confidered in what manner the
t J
R 1 c I T Y. Part III.
aaion of ekaric atmofpheres muft modify the ekari-Pi ineiplesof
city of the metil plate in various fituations. We muft Elcdtricity
nowr confider the effeas which take place when the
ekaricity is communicated to the metal plate whilft ^ment.11"
Handing upon the imperfeaiy conduaing plane j how-y—J
ever the explanation of this eafily follows from -what
has been faid above. Suppofe, for inftance, that a
Leyden phial or a conduaor were fo weakly ekarified,
that the intenfity of its ekaricity w ere only of half a
degree, or even lefs ; if the metal plate, when Hand¬
ing upon the proper plane, were touched with that
phial or conduaor, it is evident that either of them
would impart to it a quantity of its ekaricity, propor¬
tional to the plate’s capacity, viz. fo much of it as
would make the intenfity of the ekaricity of the plate
equal to that of the ekaricity in the conduaor or
phial, fuppofed of half a degree ; but the plate’s capa¬
city, now that it lies upon the proper plane, is above
100 times greater than if it Hood infulated in the air ;
or, which is the fame thing, it requires 1 bo times more
ekancity in order to ftiew the fame intenfity j there¬
fore, in this cafe, it muft acquire upwards of a hundred
times more ekaricity from the phial or conduaor. It
naturally follows, that when the metal plate is after¬
wards removed from the proper plane, its capacity be¬
ing leffened fo as to remain equal to the hundredth
part of wdiat it was before, the intenfity of its ekari¬
city muft become of 50° j fince, agreeably to the fuppo-* Cavalts'
fition, the intenfity of the ekaricity in the phial or EUallity
conduaor wTas of half a degree *. Vcl. ii. ?
Having premifed thus much refpeaing the capacity
of conductors, wx fhall now proceed to deferibe Signi-
or Volta’s method of rendering fenfible minute degrees
of ekaricity.
His method, in ftiort, is to communicate the other-Defcnptio*
w ife unobfervable quantity of ekaricity to the metallic of Volta’s ,
plate of an ekarophorus, wdiile Handing on an imper-condenfcrfe
feaiy infulating plane ; for the capacity of the metallic
plate being thus augmented, it will acquire a much
greater quantity of ekaricity than if it flood complete¬
ly infulated in the air, and wrhen it is again feparated
from the plane its .capacity will be diminifhed ; confe-
quently, its ekaricity increafing at the fame time, the
intenfity of this will be rendered manifeft either by
fparks or by means of a delicate ekarometer.
The particulats neceflary to be kept in view in this
method, are the following. The metal plate muft be
at kaft fix inches in diameter, wnth the edge wxll
rounded, and having a vamifhed glafs handle, or, in¬
ftead of the glafs, three filken firings. The inferior
plane muft be of a very imperfea conduaing nature, as
dry marble, very dry and flightly varnifhed wood, a
common piece of wxod covered with oiled filk, or fuch
like fubftance •, but let the fubftance be what it will, its
furface muft be very fmooth, and fuch as to coincide as
well as poflible with the furface of the metal plate ; on
which account, if a marble flab be chofen for the infe¬
rior plane, it will be proper to fit the metal plate to
that of the iron, by grinding one againft the other.
What Mr Cavallo found to be very fit for this purpofe
was a paper drum, confining of a common wooden
hoop, fuch as are ufed for barrels, over which a piece
of thick writing paper was parted, and on the back of
which he palled a piece. of tin-foil. The upper fur¬
face of the paper was varnifhed only once with lhell-l;ac
diffolved
by experi¬
ment.
Chap. XIII. ELECT
Principles of diffolved in alcohol or fpirit of wine. This fort of
Electricity plane has many advantages, viz. it is eafily made, and
ii (nitrated from Hghtnefs is very portable j its furface is per¬
fectly plane, excepting when the hoop is not very
ftrong, for then the contraction of the paper has powTer
fufficient to wrarp it j and laftly, as the thicknefs of the
paper and of the varnilh may be varied at pleafure, and
very ealily, the plane may be rendered of any required
degree of conducting power.
Having fuch a femi-conduCting plane and metallic
plate properly conftruCted, the former is to be laid upon
a table, and the latter is to be placed upon it, taking
care that the inferior plane be not excited by any de¬
gree of friCtion. If the furface of the inferior plane
ihould have acquired any eleCtricity by accidentally
rubbing it, &c. the belt way of freeing it of that elec¬
tricity is to pafs it two or three times over the flame of
a Candle. Now the metalliq plate is to be ftruck five
or fix times with the corner of a dry handkerchief, a
piece of dry flannel or paper, &c. j then it is to be
raifed from the inferior plane by means of its infulating
handle, and prefented to an ele&rometer, when it will
be found fenfibly eleClrified. If the metallic plate be
Ilruck while it is not in contaCl with the femi-conduCt-
ing plane, it will be found either to poflefs no eleftri-
city or an incomparably fmaller degree than it acquires
in the other mode.
By this means eleClricity may be obtained from fub-
ftances which could hardly be fuppofed eleCtrified, and
that not only in fufficient quantity to afcertain its qua¬
lity, but even fufficient to afford fparks. Signior
Volta has given to this apparatus the name of condenf-
ing apparatus.
Mr Cavallo, obferving that in ftroking the metallic
plate, in order to obtain eleClricity from various ffib-
provement ftances, and efpecially from the hand, the plate was
«lenlferCOn” 0^ten movec^ as to occafion fome friClion on the in¬
ferior plane, whereby this w7as excited, and confequently
the refult of the experiment rendered precarious,
thought of the following method of preventing fuch
motion.
Upon a vamiffied glafs handle he cemented a brafs
tube about fix inches long and three-fourths of an inch
in diameter, from the extremity of wffiich proceeded a
fine flexible wire about 14 inches long. Now7, wffien
the metallic plate was fituated upon the inferior plane,
he held the glafs handle of the brafs tube with his left
hand, in fuch a manner as that the end of the wire
might touch the plate, the reft remaining in the air.
Sometimes, in order to make a better contaCl, the end
of the above-mentioned wire wras put into a hole pur-
pofely made in the edge of the plate. In this difpofi-
tion of the apparatus, the fubftances to be tried are
ftroked upon the brals tube, and the eleCtricity pro¬
duced by them is conveyed to the metallic plate by the
wire, 'Which being fine and flexible, communicates no
motion to the plate.
Another improvement of Mr Cavallo’s confifts in
rendering fenfible degrees of eleClricity {till more mi¬
nute than thofe which may be difcovered by the con-
denfing apparatus.
Notwithftanding the great fenfibility of Volta's con-
denfer, yet fometimes the eleClricity acquired by the
metallic plate from fome fubftances was fo fmall as not
to affeCl an eleClrometer fufficiently to afcertain its qua¬
lity, or even its exiftence j hence it naturally occurred
VOL. VII. Part II.
246
Mr CavaL
lo’s im-
R I C I T Y.
729
to Mr Cavallo, that for the fame reafon for which thePrinciplesoi'
metallic plate of the condenjing apparatus manifefted HtClricity
fuch minute degrees of eleClricity as could not be j*luUme.cl
otherwife obferved, another fmaller plate, or fmall con- ^nientT'*
denfing apparatus, might be employed to render the' — y-—-<
W’eak eleClricity of the large metallic plate fenfible.
Accordingly, he conllruCled a fmall plate of about the
fize of a flfilling, having a glafs handle covered with
fealing-wax j and when the large metallic plate feemed
to be fo wreakly eleClrified as not to affeCl an eleClrome¬
ter fenfibly, he placed the fmall plate upon the inferior
plane, and touched it with the edge of the large plate j
then, after removing the fmall plate, he took up the
fmall one from the plane, holding it by the extremity
of the glafs handle, and prefented it to the eleClrome¬
ter, wffiich was generally fo much affeCted by it as to
diverge to its utmoft limits.
In this manner Mr Cavallo often obtained eleClrici¬
ty more than fufficient for afcertaining its quality, front
a fingle ftroke of the corner of a handkerchief; viz.
the large plate being placed upon the proper plane, was
ftroked once ; then being removed and prefented to an
eleClrometer, it appeared not eleClrified *, but by touch¬
ing the fmall plate with the edge of it, that fmall plate
acquired thereby eleClricity fufficient to make an elec¬
trometer diverge.
When this fecondary condenfing apparatus is ufed,
care mull be taken to hold the large plate almoft ver¬
tically while the fmall plate is touched by it. There
is no need of having another inferior plane for the
fmall plate, the large one being fufficient for both j for
immediately after taking up the large plate, weakly
eleClrified, with one hand, you lay down the fmall
plate, &c.
The fmall quantity of eleClricity that can be difcover¬
ed by this means is really furprifing, and there is hard¬
ly any fubftance, excepting the metals, or thofe wffiich
cannot be fubjeCled to trial, as w7ater and other fluids,
which will not produce fome eleClricity wffien rubbed ^
or ftroked againll the large plate of the condenfing ap¬
paratus, and that eleClricity is afterwards condenfed by
being communicated to the fmall plate. ^
The difcovery of Volta’s led to a difcovery P^net’s
no lefs important, the doubler, for which we were firftdoubler.
indebted to the Reverend Abraham Bennet of Wirkf-
worth, though the inftrument has been much improved
by Mr NichoHbn and Mr Read.
The doubler in its firft and fimpleft form confifted
of three parts, wffiich are reprefented at fig. 85. Plate
CXCI. viz. a poliffied brafs plate A, with an in- Plate
fulating handle fixed in its centre 5 a fimilar plate B
with an infulating handle fixed in its periphery, and
the cap of Bennet’s gold-leaf eleClrometer C, which
ferves as a third plate. The tw7o plates A and B are
varniffied on the under fide, and the handles are made
of mahogany fixed to the plates by means of glafs nuts
covered with fealing-wax.
The method of demonftrating the prefence ofMJfpUia
eleClncity by means of this apparatus is as follows.tion of the
Suppofe that we have to examine the eleClricity of the doubler,
plate C.
1. Place B upon C, and communicate fome eleClrici¬
ty to the latter, while the plate B is touched with the
finger. The confequence will be that C will receive a
greater degree of eleClricity than it would have been
capable of acquiring if B had not been prefent.
4 ^ 2. Remove
730 E L E C T R
Principlesof 2. Remove the communication from C, and take
Electricity the fing
er from off B, then raife this latter by its infula-
Vyexperi handle, and B and C will exhibit the oppofite
ment. Hates of electricity more ftrongly than when they are
in contaft.
3. Place A upon B, and touch A with the finger.
The confequence will be that A will receive a portion
of eleftricity of a ftate oppofite to that of B, or A will
be in the fame ftate of eleClricity with C.
4. Place B upon C, and touch B with the finger as
before, and at the fame time apply A edgeways to C.
In this fituation, A will communicate the greateft part
of its eleCtricity to C.
5. Remove A, take the finger from B, and raife B
from C. The oppofite ftates of eleCtricity in B and C,
will now be ftronger than before, on account of the
additional eleCtricity afforded by A.
6. Place A upon B again, as in the third ftage of
the procefs, and repeat the fubfequent manipulations.
In each of them the intenfity of the eleCtricity is fup-
pofed to be doubled, and by proceeding in this manner
for a certain time, the eleCtricity originally communi¬
cated to C, though at firft too fmall to affeCt the ftrips
of gold leaf, will at laft become fufficiently fenfible
249 t0 produce a confiderable divergence of them.
Moveable Though the above procefs is fufficiently fimple and
doubler by evident, yet it requires to be learned, and takes up a
Dr Darwin. certain time for jts performance. . It was therefore de-
firable that an inftrument fhould be formed which
might complete this feries of operations by a very fimple
mechanical movement. The firft inftrument conftrufted
with this view was contrived by Dr Darwin, and was
ffiown to Mr Nicholfon in the month of December
1787. This inftrument confifted of four metallic plates,
two of which were moveable by wheel-work into pofi-
tions which required them to be touched by the hand
in order to produce the effeCI. It appeared to Mr
Nicholfon that the whole operation, including the
touching, might be done by a fimple combination with¬
out wheel-work by the direCt rotation of a winch. •
This was foon afterwards effeCted, and communicated
by him to the Royal Society in 1788. Mr Nicholfon’s
defcription of his revolving doubler, was firft printed in
the 78th volume of the Philofophical Tranfaftions, and
has been reprinted by Mr Nicholfon in his Philofophi-
cal .journal for May 1800, from which we have co¬
pied it.
Fig. 86. reprefents the apparatus of the doubler fup-
ported on a glafs pillar 64- inches long. It confifts of
the following parts. Two fixed plates of brafs, A and
C, are feparately infulated and difpofed in the fame
plane, fo that a revolving plate B may pafs very near
them, without touching. Each of thefe plates is two
inches in diameter; and they have adjufting pieces be¬
hind, which ferve to place them accurately in the re¬
quired pofition. D is a brafs ball, likewife of two in¬
ches diameter, fixed on the extremity of an axis that
carries the plate B. Befides the more effential purpofe
this ball is intended to anfwer, it is fo loaded within
on one fide, that it ferves as a counterpoife to the re¬
volving plate, and enables the axis to remain at reft in
any pofition. The other parts may be diftindlly feen
in fig. 87. The ftiaded parts reprefent metal, and the
white reprefent varniffied glafs. ON is a brafs axis,
paffing through the piece M, which laft fuftains the
250
Nicholfon’s
revolving
doubler.
Plate
CXCI.
I C I T Y. Partin.
plates A and C. Atone extremity is the ball D al-Principles of
ready mentioned *, and the other is prolonged by the Ele&ricity
addition of a glafs flick, which fuftains the handle L ^u^ra^e.‘
and the piece GH feparately infulated. E, F, are pins 'ment?1"
rifing out of the fixed plates A and C, at unequal dif-1 y—
tances from the axis. The crofs-piece GH, and the
piece K, lie in one plane, and have their ends armed
W'ith fmall pieces of harpfichord-wire, that they may
perfeflly touch the pins EF in certain points of the re¬
volution. There is likewife a pin I, in the piece M,
which intercepts a fmall wire proceeding from the re¬
volving plate B.
The touching wires are fo adjufted,' by bending, that
when the revolving plate B is immediately oppofite the
fixed plate A, the crofs-piece GH connefts the tw7o
fixed plates, at the fame time that the wire and pin at I
form a communication between the revolving plate and
the ball. On the other hand, when the revolving
plate is immediately oppofite the fixed plate C, the ball
becomes connected with this laft plate, by the touching
of the piece K againft F 5 the two plates, A and B,
have then no connexion with any part of the appara¬
tus. In every other pofition the three plates and the
ball will be perfectly unconnefted with each other. 2^T
Mr Bennet and Mr Cavallo obferved, foon after Defedls of
the difcovery of the doubler, that it never fails to ex-the doubler,
hibit an elejftric ftate by the mere operation, without
any communication of dle&ricity being previoully made.
Mr Bennet endeavoured to find out a method of de¬
priving the doubler of this inherent electricity, and af¬
ter a number of trials, he confidered the following
as the beft mode of anfwering this purpofe. 252
He conneded the plates A and C together by a Mr Ben-
wire hooked at each end upon two fmall knobs on the ™c’^e
backs of the plates, the middle of the fame wire touch- thefe. S
ing the pillar which fupports the doubler. Another
wire was hooked at one end upon the back of the plate
B, and at the other end, to the brafs ball which coun¬
terbalances this plate. Thus all the plates were con-
neCted with the earth, and by turning the handle of
the doubler, it might be difcharged of eleClricity in
every part of its revolution.
After often trying this method of depriving the
doubler, Mr Bennet obferved that its fpontaneous
difcharge was almoft ahvays negative. Fie then touch¬
ed A and C with a pofitively charged bottle, and turn¬
ed the doubler till it produced fparks for a long time
together •, and after this ftrong politive charge he hook¬
ed on the wires as above, and revolved the plate B
about a hundred times, winch fo deprived the doubler
of its pofitive eleClricity, that wiien the wires were
taken off, it produced a negative charge at about the
fame number of revolutions which it required be¬
fore.
The pofitively charged bottle wras again applied, and
the wires being hooked upon the plates as before, B
wTas revolved only fifty times, yet this was found fuffici-
ent to deprive it of its pofitive charge, and in many
experiments five or fix revolutions were fufficient ; but
he never thought it fafe to flop at fo few, and therefore
he generally turned the handle 40 or 50 times between
every experiment.
Left eleCtricity adhering to the eleClrometer fhould
obftrud the above experiments, Mr Bennet did not
let it Hand in contaCl w7ith the doubler during its revo¬
lutions,
Chap,
Bennet's
the errors
of the
doubler.
254
Cavallo’s
.XIII. ELECT
Principles otlutions, but toucbed tbe plate A with the cap of the
Electricity elearometer, after he fuppofed its eleftricity was be-
J come fufficiently fcnfible j but left even this contaft
fliould communicate any elearicity, he made a cap of
fliell lac for his ele&rometer, having a fmall tin tube
in the centre, to which the gold leaf was lufpended with¬
in the glafs, and a bent wire was fixed to the top which
might ealily be joined to the plate A of the doubler,
and thus the gold leaf was more perfectly infulated,
and the eleftricity could not be diffufed over fo large a
furface. The glals which infulates the plates and
New Expt- tool's piece 0f the doubler was alfo covered with fhell
rimints. _ r
2^3 lac *.
Robifon’s Dr Robifon conceived that Mr Rennet’s original
propofal l°r ftoubler might be freed from error as far as was poftible,
obviating eTnpl0ying a thin ftratum of air as the intermedium be¬
tween the three plates. The method which he propofes for
effe£ling this is very ingenious. Stick on one of the plates
three very fmall fpherules, made from a capillary tube of
glafs or from a thread of fealing-wax. 1 he other plate be¬
ing laid on them, refts on mere points, and can fcarcely
receive any friclion, which may difturb the experiment.
Mr Cavallo, finding that Mr Rennet’s mode of ob-
viating the inconveniences of the doubler did not iuc-
11Clty‘ ceed with him, conftrufted a new inftrument, which he
calls a colleBor of eleBricity, and a defcription of which
was inferted in the 78th volume of the Philofophical
Tranfaftions. It conlifts of a plate of tin, fupported by
two upright fticks of glafs •, on each fide of which plate
are two frames of wood covered with gilt paper, which
do not touch the tin-plate, but ftand parallel to it at a
little diltance. Thefe frames are faftened to the plat¬
form of the inftrument by hinges ; fo that if electricity
be communicated to the plate, it will receive a large
quantity w ithout any confideiable intenfity, becaule its
capacity is much augmented by the vicinity of the
plane of gilt paper on each fide. Rut if thefe planes
be thrown back into the horizontal pofition, which is
eafily done by means of their hinges, the eledtricity,
which before was compenfated in the plate, wall have
its intenfity greatly increafed. An electrometer con¬
nected -with this plate wall therefore (how figns of elec¬
tricity by means of a communication made betwreen a
large flock of eleCtricity, and the tin-plate in its firft
pofition, though the intenfity of that flock may have
been too fmall to have affeCted the eleCtrometer without
this contrivance.
It does not appear, in the author’s defcription of this
inftrument, that it removes the equivocal effeCt of the
doubler ; for it is evident that it does not in its Ample
procefs, enter the province of the doubler in winch this
effeCf takes place. The doubler requires fix or feven
turns before it will exhibit fpontaneous eleCtricity •, at
which period the firft charge is magnified above twelve
thoufand times ; but his Ample inftrument will fcarcely
exceed one hundred times, and therefore requires the
eleftiicity to be one hundred and twenty times as ftrong
as that which caufes the uncertainty of the doubler.
Whence it may be inferred, that the doubler would
have aCted unequivocally with all fuch eleftricities
as this inftrument is capable of exhibiting *.
Mr Cavallo has lince conftruCted another inftru-
ofekdlrlci ment’ which he calls a multiplier of eleclricily, and
tv, "which he confiders as quite free from equivocal re-
fulls.
* Nkhol-
Jon's Jeur.
4tO, vol. i.
255
Cavallo’s
multiplier
ft 1 C I T Y.
751
“ The figs. 88, and 89. reprefent this Retv inftru-Prmapk^ot
ment, and they are about two-thirds of the real fize. moated
QRS is the bottom board, upon which are fteadily fix- eXperu
ed on the glafs fticks H, G, two flat brafs plates A and ment.
C.— R is a fimilar brafs plate fupported by a glafs ftick
I, wdrich is cemented in a hole made in the wooden
lever KL, which moves round a fteady pin K, that is
fcrewed tight in the bottom board. Ry moving this
lever backwards and forwards, the plate R may be al¬
ternately put in the two fituations reprefented by the
figures. N is a thick brafs wire fixed tight into the
bottom board. There is a fourth brafs plate D, fimi¬
lar to the other three, which is fupported not by glafs,
but a wire } and this wire is fcrewed fall; to an oblong
piece of brafs TP, that Aides in a grove made for the
purpofe in the bottom board QRS; fo that by apply¬
ing a finger’s nail to the notch on the end F, the Aid¬
ing piece FP may be drawn out either entirely or to a
certain length, and of courfe the plate D will be re¬
moved to any required diftance from the fixed plate C.
I need not fay any thing particular refpeCting the
fockets of thofe brafs plates, they being clearly indicat¬
ed in the figures, excepting only that the focket of the
plate A reaches as high as the top of it, and ferves to
receive a ware, or other apparatus, on certain occa-
fions.
The parts of this inftrument are fo adjufted, as that
when the lever is in thefituation of fig, 88. viz. is pufti-
ed as far toward (,) as it can go, the plate R comes pa¬
rallel to the plate A, and about one-twrentieth of an
inch diftant. At the fame time the extremity of the
wire OM juft touches the fixed ware N, and of courfe
renders the plate R uninfulated. Rut as foon as the
lever begins to be moved towards S, the communica¬
tion of the plate fl with the wire N, or with the
ground, becomes interrupted, and R remains infulated.
And when the lever has been moved as far as it can
go towards S, the wire M comes in contadft with the
plate C, as ftrowm in fig. 89. Then the twTo plates R
and C communicate with each other, though they are
otherwife infulated. The fourth plate D being fup¬
ported by a wire, communicates with the ground j and
W’hen the Aiding piece PF is puftied home, it ftands
parallel to, and at about one-twrentieth of an inch from
the plate C.
When the inftrument is fituated as in fig. 88. if an
eleftrified body be brought into contaft with the plate
A, this plate will imbibe a great deal more of that
eleftricity than it would otherwdfe, becaule its capacity
is increaled by the vicinity of the uninfulated plate B,
and therefore, if after the communication ol that elec¬
tricity, the plate R, by moving the lever, be removed
from that fituation, and A be made to touch an elec¬
trometer, this wall be electrified more fenlibly by it,
than it would have been by the contaCt of the original
eleCtrified body itfelf. So far the plate A aCts like a
condenfer, or collector of eleCtricity. Rut let us now
confider the inftrument as a multiplier.
When the plate A has received a fmall quantity of
eleCtricity by the contaCt of any eleCtrified body what¬
ever, and that body is removed, the plate R being un¬
infulated and oppofed to the eleCtrified plate A, will,
like the metal plate of an eleCtrophorus, acquire the
contrary eleCtricity, by either receiving from, or giv¬
ing to, the ground fome eleCtric fluid, according as
4 Z 2 the
732 ELECT
Principlesofthe plate A happens to be elearified. Thus, fuppofe
illuftrated ^as ^een_ elearified pofitively, B will become
by experi-ne§a^ve» an^ vice verfa. If now the lever be pulhed
inent. towards S, tlie plate B will remain elearified negative-
' v ' ly, the communication with the ground being cut off j
and when B comes into the fituation reprefented by
fig* at which time the ware M touches the plate
C, the negative elearicity of B will go to C, becaufe
the capacity of C for holding elearicity is confiderably
augmented by the vicinity of the uninfulated plate D.
If after this the lever be moved back again to its firft
fituation, B will be made negative a fecond time in
the lame manner as before : and by puffing the lever
again towTards S, that fecond charge of negative elec¬
tricity wall be communicated from B to C ; and thus,
by repeating the operation, which confilfs in merely
moving the lever backwards and forwards, a confider-
able quantity of negative electricity will be accumulated
upon C.
In fa£t, the aCtion of this inftrument refembles very
much that of an eleCtrbphorus j for the plate Amay repre-
fent the excited refinous plate, B may reprefent the
metal plate of the eleftrophorus, and C is a kind of
refervoir, into which the fucceffive charges of the plate
B are collected.—When a number of thofe charges or
portions of eleCtricity has been communicated to C, if
the Hiding piece FP be drawm out about an inch, and
of courfe the plate D be removed to the like diitance
from the plate C, the capacity of the plate C will
thereby be much diminiffed : and therefore if an elec¬
trometer be brought into contaft with it, the eleftricity
will be mamfefied : whereas the electricity originally
communicated to the plate A, could not have affefted
an eleCfrometer in any fenfible degree.
In ufing this inftrument, 30 or 40 additions of elec¬
tricity are the utmoft number practicable \ for after
that number the augmentation of the charge upon C
will not go any farther; the limit of which is, wffen
the charge of C is increafed to fuch a degree, as to
leave a portion of eleCtricity upon B, equal to that
portion which B can receive from the aCtion of A.
In this cafe, let C touch an eleCtrometer as mention¬
ed above, and if the eleCtrometer does not diverge,
proceed to a fecond procefs *, for though its pendulums
do not diverge, yet fome eleCtricity remains in them,
which muft not be ditturbed, as it will help the effeCt
of the fecond operations, wffich is as follows : Puff in
the Aider FP, and go on moving the lever backw-ards
and forwards as before, by W'hich means, after a cer¬
tain number of additions, the plate C will acquire a
fecond charge, about as high as the former : and if
then the Aider FP be pulled out, and C brought into
contaCt with the fame eleCtrometer, the divergency of
the pendulums, which before was either not at ail or
hardly perceptible, wdll thereby be rendered more con-
fpicucus : and thus it may be increafed ftill farther by
a third and a fourth operation. But if, notwithftanding
thcfe repeated operations, the eleCtrometer ffould be
found not to diverge, the quantity of eleCtricity may
ftill be augmented by another method, which is, by
* Cavallo's communicating that little eleCtricity of C to the plate
Ek£iricity, A of another inftrument of the fame fort, and proceed-
vol. iii. jng with that in the manner already defcribed
256 In Nicholfon’s Journal for September 1804, is a
R I c I f Y. Fart 111.
paper by Mr W. Wilfon, containing a defcription of Ymciples&f
an inftrument which Mr Wilfon calls a compound con- ^ttfncny
denfer of e/edricily, and which he confiders as an im-
provement on Mr Cavalio’s multiplier, anfwering the
purpofe of a condenfer, a fingle and double multiplier,y—J
and a doubler. The inftrument is very complicated,
containing no lefs than fix plates. Like all complicated
inftruments of this kind, it is of courfe fubjeCt to er
ror from its own fpontaneous eleCtricity.
Mr Nicholfon has conftrufted an inftrument for af- Nichoifon’s
certaining fmall degrees of eleCtricity, without, as herPinnin?
fays, a poffibility of equivocal refult. This inftrumentcondenter*
he calls the/pinning condenfer, and it is thus defcribed
in his Journal for April l 797.
“ Fig. 90. reprefents a vertical feCtion of the inftru-
ment. A is a metallic vafe, having a long fteel axis CXCI.
which paffes through a hole in the ftand H at K, and
refts on its pointed end in an adjuftable focket at C.
The ufe of the vafe is, by its weight, to preferve, for
a confiderable time, the motion of fpinning wffich is
given by the finger and thumb applied to the nob at
the top of the inftrument. The ftiaded parts D and E
reprefent tw*o circular plates of glafs nearly i-i inch in
diameter. The upper plate is fixed to the vafe, and
revolves with it; the low^er is fixed to the ftand. In
the lowrer plate are inferted two metallic hooks, diame¬
trically oppofite each other, at F and G. They are
cemented into holes drilled in the edge of the glafs,
which is near twTo-tenths of an inch thick. In the up¬
per plate are inferted in the fame manner two fmall
tails of the fine Aatted wire ufed in making filver lace.
Thefe tails are bended dowm fo as to ftrike the hooks
in the revolution, but in all other pofitions they remain
freely in the air without touching any part of the ap¬
paratus. At C is a fcrewq wffich by raifing or lower¬
ing the vafe keeps the faces of the glafs plates from
each other at whatever diftance may be required. The
faces of the glafs plates which are oppofed to each other
are coated with fegments of tin-foil, as reprefented, fig.
91 and 92, the latter of which reprefents the upper
plate. Each of the tails communicates with the tin-
foil coating to which it is contiguous, as does alfo the
hook F with that coating of the lower plate neareft to
it. But the hook G is entirely infulated from the
whole apparatus, and is intended to communicate only
with the ele&rified body or atmofpherical conduftor L.
The lower coating neareft to G is made to communicate
permanently with the ftand H, and confequently with
the earth.
In this fituation, fuppofe the motion of fpinning to
be given to the apparatus, and the effects will be thefe ••
One of the tails will ftrike the hook G, by which
means the upper coating annexed to that tail will af-
fume the eleftric ftate of L by communication. But
this ftate, on account of the proximity of the low7er un¬
infulated plate to wffich it is, at that inftant, direftly
oppofed, will be as much ftronger than that of L, as a
charge exceeds fimple electrization. The tail G with
its plate or coating proceeds onwrard, and after half a
revolution arrives at the fituation to touch the hook F.
The upper coating, the lower on the fide of F, the
hook F itfelf, and the tail V, muft then conftitute one
jointly infulated metallic mafs, in which no charge fub-
lifts, but which is Amply electrified by the whole charge
received
XIII,
Prim i | lies of received at G,
Chap.
ELECT
And of this mafs the furfaces of the
Eieftncity plates themfelves, conftituting the eleftric well of
illuttrated pranyjnj w;n throw out all their eleftricity to the
h^ent” ^ook and tail. But the coating and its tail inftantly
t v—L-. pafs round, leaving F eledrified, and proceed to bring
another charge from G and depofit it as before. 1 he
balls at F are therefore very fpeedily made to diverge.
It is fcarcely neceffary to remark, that the two upper
coatings do nothing more than double the fpeed of the
operation 5 one of the tails being employed in collect¬
ing, while the other is depofiting *, and that the gold-
leaf eleCtrometer may be advantageoully fubilituted for
the cork-balls.
The inftrument I caufed to be made was five inches
high. The receiving fide G was connefted with a
coated jar of four fquare feet coating, and the giving
fide F was connected with Bennet’s gold-leaf eleftro-
meter. The eleClrometer was rendered as ftrongly
pofitive as it was capable of being, and the jar wTas
rendered negative, by giving it as much of that power
as was produced by drawing a common flick of feal-
ing-wax once through the hand. In this date the jar
was incapable of attracting the finefl thread. The vafe
was then made to fpin j and the effeCt was, that the
leaves of the electrometer fir it gradually collapfed, and
then in the fame manner gradually opened, and ftruck
the Tides of the glafs of the eleCtrometer with negative
electricity. The experiment was renewed and repeated
with every requifite variation.”
To conclude, the methods of afeertaimng minute
degrees of eleCtricity may be reduced to three.
I. If the abfolute quantity of eleCtricity be fmall and
pretty much condenfed, as that produced by a fmall
tourmaline when heated, or by a hair when rubbed, the
ele6tricity|; only effectual method of manifefkng its prefence, and
B a^deli Pertaining its quality, is to communicate it to a very
cat^elec- delicate eleCtrometer, i. e. one that is very light and has
trometer; no great extent of conducting furface.
260 2. When we with to afeertain the prefence of a con-
% the co^' fiderable quantity of eleCtricity, which is difperfed, or
JpJier m-1 ' exPanded into a great fpace, and is little condenfed, fuch
" ’ as the conftant eleCtricity of the atmofphere in clear
weather, or fuch as the eleCtricity which remains in a
large Leyden phial after the firft or fecond difeharge •,
this may be belt afeertained by means of Cavalto’s col-
leclor or multiplier, or by the condenfer with Cavallo’s
improvement of the fmall plate.
3. When the eleCtricity to be afeertained is neither
very confiderable in quantity nor much condenfed, fuch
douMer ard as t^le eleCtricity of the hair of certain animals, of the
a delicate furface of chocolate when cooling, &c. In this cafe
the belt method is to apply a metallic plate furnilhed
with an infulating handle, fuch as one of the plates of
the doubler, to the eleCtrified body, and to touch the
plate with a finger wdiile it remains for fome time in this
fituation 5 which done, the plate is to be removed and
brought near a fenfible eleCtrometer •, or its eleCtricity
may be communicated to the plate of a fmall condenfer,
by wThich it will be rendered more confpicuous. In this
operation care mult be taken not to bring the plate too
near the body whofe eleCtricity is to be examined,
left the friction, likely to happen between the plate
and the body, ftrould produce fome eleCtricity, the
origin of which might be attributed to fome other
caufes.
R I C I T Y.
733
258
Three ge¬
neral me¬
thods of af-
certaining
fmall de¬
grees of
condenfer;
25i
By one of
the plates
of the
eledlrome
ter.
, „ . Principles of
Chap. XIV. Mifcellamous and additional ILxperi- Electricity
meats and Qbfervations. illuftrattd
J by experi-
Mr Nicholfon, in his Journal for September 1797’ ment.
propofes wdiat appears to be a valuable improvement in  v ■
Bennet’s eleCtrometer. ,
“ There are, (fays he) twTo particulars in which this °ve°n 3
excellent inftrument appears capable of improvement: ment Qf
the firft, to render it portable, wnthout danger to the bennet’s
gold-leaf, and the fecond to exprefs its various degrees'eleCtrome-
of electrization by a fcale of divifions. ter*
I have refteCted much on the probable means of fe-
curing the gold-leaf from fraCture by carriage, but
hitherto with little profpeCt of fuccefs. There was fome
hope that a fingle flip of this gold might be preferved
in a fheath or box, wuth its lidcs very nearly in contaCt j
but when I placed fuch a flip upon a gilded piece of
wood of the fame fuperficial dimenfions, to which it was
faftened at one end, its flexibility was fuch that the leaf
very readily Hided along the furface of the wood, and
became full of folds, by inclining the faftened end a very
few degrees lower than the other extremity. There
was ftill lefs immediate expectation that the flips could
be aCtually and repeatedly confined between two leaves
or culhions, as in the book of the gold-beaters, without
their being broke by continual agitation. To this,
howrever, my attention will probably be direCted wdren
I may again relume this objeCt. In the mean time, I
recommend it to other philofophers, as a very defir-
able improvement in the mineralogical apparatus, and
Ihould rejoice to be anticipated by their fucceisful
refearches.
The weight of one flip of gold-leaf, in the eleCtro¬
meter of Bennet, is about 1-600th part of a grain) but
this, as wTell as the fenlibility of the inftrument, muft
vary, not only from the figure and dimenfions of the
piece, but the nature and thicknefs of the gold itfelf *. * Ptil,
It leemed, therefore, unneceffary to endeavour to render 70ur,,‘
two of thefe inftruments comparable with each other. u
All that could be done was, to diftinguifti the different
intenfities as fhewn by the divergencies of the leaf) or,
as I have taken it, the diftances at which they ftrike a
pair of uninfulated metallic bars. In Plate CXCIII.
fig. 93. A reprefents the infulated metallic cap, from
which, at C, depend the two narrow^ pointed flips of gold-
leaf. BB is the glafs tirade, which ferves to fupport
the cap, and defend the leaves from the motion of the
furrounding air. DD are twTo flat radii of brafs, which
open and ftrut by means of one common axis, like a pair
of compaffes. By a contrivance of fprings, they are
difpofed to open wrhen left at liberty ) but the micro¬
meter fcrewr E ferves to draw a nut, v/hich has two rteel
bars, with a claw at the end of each, that enters into a
correfpondent flit, in tw o fmall cylindrical pieces, to
which the radii are fixed refpeCtively. This apparatus
is feen in another pofition in fig. 94. KL reprefents a
piece of brafs, which ferves as the frame for the work,
and fits the low^er focket of the eleCtrometer, FF, fig. 3.
In this the letters IH indicate the cylindrical pieces
wrhich carry the radii, and are feen from beneath. On
the fide of the nut G, one of the fteel drawing pieces
is feen ; the other being on the oppofite fide, and con-
fequently not vifible. Towards L appear the two re-ac¬
tion fprings. The other parts require no verbal de-
feription.
Plate
CXUII.
In
263
His obfer-
vations on
the glafs
cafe of this
734 ELECT
Principles of In the common conftruftion of the gold-leaf elec-
flluftrptcd trometer> tllcre are two pieces of tin-foil palled on
by expei i- 0PP°iite parts of the internal furface of BE j againft
ment. v.hich the gold-leaf ftrikes when its eleftricity is at
■v the maximum. If the radii DD be left at the greateft
opening, our inftrument does not then differ from
that in common ufe. But if the divergence produced
by the contact of an atmofpheric condu£tor, or any o-
ther fource of eledlricity, be fo fmall as to render it
doubtful whether the leaves be electrified or not, the
radii may then be brought very gradually together by
means of the fcrew, until the increafed divergency from
their attractive force be fufficient to afcertain the kind
of eleClricity polfeffed by the leaves. In this and all
other cafes, the divifion on the micrometer head, which
ftands oppofite the fixed index, at the time the leaves
itrike the radii, will lhew the greater or lefs degree of
intenfity.
In his Journal for January 1799, he has the follow¬
ing remarks on the glafs cafe of this inftrument.
“ Under all the uncertainties concerning" the place
inftrument. occupied by the eleCtric charge of coated glafs, though
it may feem unfair to make any inference refpeCting
glafs which is uncoated, yet, upon the whole, there ap¬
pears to be a probability that the interpofition of naked
glafs may impede the aClion of eleftrified bodies. This
♦■jueftion more immediately points at the tube in which
the gold-leaf eleCtrometer of Bennet is inclofed. To
-determine whether the tube of the eleCtrometer does af-
feCt the eleCtric ftate of the included leaf, either by com-
penfation or otherwiie, I took a piece of window-glafs
■eighteen inches long, two inches wide and one-twentieth
of an inch thick, which I cleaned very well, and then
pafied it feveral times through the hot air over the fiame
of a candle. In this ftate one end of the glafs was laid
gently upon the eleCtrified plate of Bennet’s eleCtro¬
meter, and then fuddenly raifed by a turn of the wriit.
It was fcarcely poflible to difeern that the leaves were
at all affeCted j but when the eleCtrometer was in the
plus ftate a very flight collapfion was produced by
railing the glafs, and the contrary effeCt was produced
when the eleCtrometer was negative. Some days after¬
wards the experiment was repeated, after the gold-
leaf had been changed for other pieces, which were
very pointed and delicate in their movements. The
refult was, that the glafs was always Ihewn by the
eleCtrometer to be in a weak pofitive ftate •, and,
when the eleCtricity of the eleCtroxpeter was made plus,
the collapfion was equal to the divergence when it was
minus.
In making thefe experiments I had previoufly fup-
pofed that the influence of the metallic ftate of the
■deCtrometer would produce fomewhat of the nature of
a charge upon the glafs ; and confequently that the in¬
tenfity of the leaves would have been diminilhed during
the exiftence of that charge 5 and alfo, that in fuch a
cafe the aCtion of the metal through the glafs would be
fubjeCt to the fame diminution as in the feries of jars.
But as the glafs did not appear to aft in this man¬
ner, it feems proper to conclude that clean glafs
does not alfeCl: the eleCtric ftate of bodies by its
vicinity, and that the divergence of the balls or the
gold-leaf in the electrometers of Cavallo and Ben-
net is not diminilhed by the tube which furrounds
ihem.
R I C l T Y. Part III.
From a variety of experiments it was clearly afeer-Principles of
tained that the metallic coatings, though by their vici- Ekdtricity
nity they may diminifli the intenfity of the eleCtric ftate 'Iluftrate.ci
in the leaves, do neverthelefs increafe the angle of di-
vergence by their attraction. 1 —-y t
When the gold-leaf eleCtrometer is made with a very
fmall tube, its fenfibility is fomewhat increafed by the
nearnefs of the coatings • but the chance of rendering
it unferviceable from cafual friCtion, rvhich excites
the glafs, and caufes the gold-leaf to ftick to it, to¬
gether with the lefs perfeCt view of the divergence
through a tube of fmall curvature, afford reafons whv
a diameter of lefs than an inch Ihould be reject¬
ed. Other reafons of convenience indicate that the
diameter of the glafs Ihould not much exceed this
quantity.
I was once induced to think that the confiderable
magnitude of the cap of Bennet’s eleCtrometer might
render it lefs capable of being aCted upon by fmall quan¬
tities of eleCtricity. Experiment did not however give
much countenance to this fuppofition. By trials with
heads of different fize, the fmalleft were found to be ra¬
ther more fenfible to extremely minute electricities, and
lefs fo to fuch as were greater. The influence of very
weak eleCtricity may produce the oppofite ftate in the
whole of a fmall head, but only in part of a larger •,
the remaining part of this laft affuming the oppofite ftate,
and robbing the leaves of part of their intenfity. But
in higher electricities the whole of the large head may
be urged to give eleCtricity to the leaves, in a quantity
which the fmaller head could not give without acquir¬
ing a higher degree of intenfity, and confequently
more ftrongly refilling the defired procefs. It appears
therefore that the maximum of effeCt with a given
eleCtricity, aCting without communication, will not
be obtained but by a head of a definite figure and mag¬
nitude.”
In N° 82. experiment 5. we deferibed a method of Other me-
imitating the planetary motions by the motion commu-thodsof
nicated by the current of air from eleCtrified points •, this‘m‘tat^nS
may be done in various other ways, of which we lhall^ae Pidlie‘
only add the following. lions.010"
1. From the prime conductor of an eleCtric ma¬
chine fufpend fix concentric hoops of metals at differ¬
ent diftances from one another, in fuch a manner as
to reprefent in fome meafure the proportional diftances
of the planets. Under thefe, and at the diftance of
about half an inch, place a metallic plate, and upon
this plate, within each of the hoops, a glafs bubble
blown very thin and light. On eleCtrifying the hoops,
the bubbles will be immediately attracted by them, and
will continue to move round the hoops as long as the
electrification continues. If the eleCtricity is very
ftrong, the bubbles will frequently be driven off, run
hither and thither on the plate, making a variety of
furprifing motions round their axis 5 after which they
will return to the hoop, and circulate as before ; and
if the room is darkened, they will all appear beautifully
illuminated with eleCtric light.
2. Provide a ball of cork about three quarters of an
inch in diameter, hollowed out in the internal part
by cutting it in two hemifpheres, fcooping out the in-
fide, and then joining them together with pafte. Hav- ■*
ing attached this to a filk thread between three and
four feet in length, fufpend it in fuch a manner that it
may
2
Chap. XIV.
E L E C T R
Principksof may juft touch the knob of an eleftric jar, the outiide
Electric ty 0f which communicates with the ground. On the firft
contact it will be repelled to a confiderable diftance, and
\nent. after making feveral vibrations will remain ftationary j
but if a candle is placed at fome diftance behind it, fo
that tire ball may be between it and the bottle, the ball
will inftantly begin to move, and will turn round the
knob of the jar, moving in a kind of ellipfis as. long
as there is any electricity in the bottle. J. his ex*
periment is very ftriking, though the motions are
far from being regular j but it is remarkable that
they always affedt the elliptical rather than the circular
form.
In the table of conductors we have placed flame,
flmohe, and the vapour of hot water. 1 hat thefe va¬
pours are condudtors may be {hewn by the following ex¬
periments.
name* Exper. i.—Bring the knobs of two metallic dif-
condudtor. charging rods, communicating the one with the outiide,
and the other with the inficle of a charged phial, oppo-
lite each other, each wdthin an inch of the dame of a
candle, fo that the dame may be in the middle between
them. The dame will be feen to fpread on each lide
towards the knobs, and will produce the difcharge of the
I C I T Y.
735
265
Flame a
266
Cuthbert-
fon’s mode
of diftin-
guifliing
the two
electrici¬
ties.
* Nicbol-
fon s ‘Journ.
Nov. 1802.
267
Smoke and
fteam con¬
ductors.
Jar-
Mr Cuthbertfon has propofed a method of diftingmfti-
ing politive from negative eleftricity by the dame oi a
candle. He places "the dame of a candle exa£tly in the
middle between tw'o metallic balls at the diftance of
four inches from each other, fo that the centre of the
dame is in a line with that of the balls. 1 he balls are
about three-fourths of an inch in diameter, and commu¬
nicate by infulated wires, the one with the pofltive and
the other with the negative conductor. If the machine
be then put in motion, the dame will wraver very much,
but will feem to incline rather to the negative than the
pofltive ball. After turning the machine for about 50
revolutions (if the glafs be a plate of two feet diame¬
ter), the negative ball will begin to grow warm, while
the pofltive ftill remains cold. After 200 revolutions,
the negative ball will become too hot to be touch¬
ed, while the pofltive will continue as cold as at
firft *.
A charged phial may be gradually difcharged by
pading it for fome time backwards and forwards
through the dame- of a large candle, fo that the dame
may a£l alternately on the knob and the outfide
coating.
Exper. 2.—Sufpend a cork-ball eleftrometer about
four or five feet above the prime conductor of an elec¬
trical machine j then turn the winch very gently, and
it will be found that the balls do not diverge. Now
place a green wrax taper juft blown out in the prime con¬
ductor, fo that its fmoke may afcend towards the balls,
and thefe will diverge a little with the fame degree of
motion communicated to the machine.
The fame effecft, but in a lefs degree, will be produ¬
ced if, inftead of the taper, a veffel of hot wnter is pla¬
ced below the balls, thus {hewing xErzX fleam is a con¬
ductor, though inferior to fmoke in its conducing
power.
Thefe experiments are by Mr Henly, and are among
feveral others related by him in the 64th volume of the
Philofophical Tranfaiftions. His'reafon for employing
green taper, was, that on account of the verdigris which Principles of
it contained, it occafioned much fmoke with little
heat. . by experi-
It has been remarked in the Introduftion, that glafs, ment.
though one of the moil perfect electrics when cold, be- v ' 1
comes a condu&or when heated red hot. This is
proved by the following experiment, which alfo {hews ot|ier elec_
that other eledtrics change their nature when heated. tr,cs be-
Take a finall glafs tube of about one-twentieth of come con-
an inch in diameter, and above a foot long j clofe it at Tidturs
one end, and introduce a wire into it, fo that it may ioe
extended through its whole length : let two or three
inches of this ware projedl above the open end of the
tube, and there fallen it with a bit of cork } tie round
the clofed end of the tube another wire, which will
be feparated from the wire within the tube only by the
glafs interpofed between them. In thefe circumftances
endeavour to fend a ftiock through the two wires ; i. e.
the wire inferted in the glafs tube, and that tied on its
outfide, by connecting one of them with the outfide, and
touching the other with the knob of a charged jar, and
you will find that the difcharge cannot be made, unlefs
the tube be broken 5 becaufe the circuit is interrupted
by the glafs at the end of the tube, which is interpofed
between the two wires. But put that end of the tube
to which the wire is tied into the fire, fo that it may
become juft red hot, then endeavour to difcharge the
jar again through the wires, and you will find that the
explofion will be eafily tranfmitted from wire to wire,
through the fubftance of the glafs, which, by being made
red hot, is become a conductor.
In order to afcertain the conducting quality of hot
refinous fubftances, oils, &c. bend a glafs tube in the
form of an arch CEFD, fig. 95. and tie a filk fixing
GCD to it, which ferves to hold it by when it is to be
fet near the fire ; fill the middle part of this tube with
rofin, fealing-wax, &c. then introduce two wires, AE,
BF, through its ends, fo that they may touch the rofin,
or penetrate a little wTay in it. This done, let a perfon
hold the tube over a clear fire, fo as to melt the rofin
within it; at the fame time, by connecting one of the
wires, A or B, with the outfide of a charged jar, and
touching the other with the knob of the jar, endeavour
to make the difcharge through the rofin, and you will
obferve that, while the rofin is cold, no {hocks can be
tranfmitted through it : but it becomes a conductor ac¬
cording as it melts, and wrhen totally melted, the {hocks
will pafs through it very freely.
The electric power of glafs may alfo be deftroyed by Glafs and'
reducing the glafs to powxler. This was afcertained by other elec-
M. Wilcke f, and Dr Prieftley J j but it has been moft tr‘cs when
fatisfaflorily proved by M. Van Swinden, in the foh°w-
ing experiments. _ _ _ conductors.
Exper. 1.—He covered a cafe of white iron with pow-1 Mem. de
dered glafs, fo as to form a cake about an inch thick, ■a.k’Acadde
foot long, and eight inches broad, and he placed above f,*x*
this cake, another plate of iron fo as to form a coating,
He then attempted to charge this coated plate, but with- ^ ^4, f, 4,
out fuccefs; he could produce no Ihock.
Exper. 1.—Suppofing that the conducting power of
the glafs in the above experiment might arife from
fome humidity which it had contracted, he dried it in a
crucible, and repeated the experiment. In this cafe, it
appeared {lightly electric, fo long as the machine was
worked,
736 ELEC T
Principles of worked, but when this was flopped the plate of powder-
mnftrTted ed glafs UO lon8er affeaed the eleftrometer.
by e.;peri- Expet', 3. Into ajar, coated on the outlide, he put
ment. ^ quantity of powdered glafs, and having furnilhed it
 ' in other refpefts like a Leyden phial, he proceeded to
<Van, , examine whether it would receive a charge. He found
I'Analllie de 11 j0uld be completely charged, a proof that
V E!Pa riche tJe powdered glafsacted the part of a condudtor *.
a de Mag. By fimilar experiments M. Van Svvinden found that
jietfne, flowers of fulphur afted as a conductor though more
tom.i.p.43. imperfe^iy than pow'dered glafs.
Velocity of Soon after the difcovery of the Leyden phial and
the electric ^hock produced by it, it became a defirable objeft with
fliock. ele&ricians to afcertain how far the Ihock might be
conveyed, and .low long a time would be required to
convey it to any confiderable diftance.
The French philofophers were the firft to appear in
this field, but they did little more than excite the Eng-
liih to go far beyond them in thefe great undertakings.
A circuit was made by the former of 900 toifes, con-
flfting of men holding iron wires betwixt each two,
through which the eleftric fliock was fenfibly felt. At
another time they made the fliock pafs through a wire
two thoufand toifes in length, that is, near a Paris
league, or about two Englifli miles and a half j though
part of the wires dragged upon wet grafs, wrent over
chafms, hedges, or palifades and over ground newly
ploughed up. . Into another chain they took the w-ater
of the bafon in the I huilleries, the furface of wdiich
w as about an acre, and the phial wras difcharged
through it. b
.Mr Monnier the younger, endeavoured to deter¬
mine the velocity of the eleftric power ; and for this
purpofe made the Ihock pafs through an iron wire of
95° toifes in length, but he could not obferve that it
Ipent a quarter of a fecond in pafling it. He alfo
round, that when a ware of 1319 feet, with its extre¬
mities. brought near together, w7as elehfrified, that the
elehfricity ceafed at one end the moment it wras taken
271 joff at the other.
mention t. ^Ut ^ rhefe attempts of the French wmuld fcarcely
Ibis inquiry have deferved to be mentioned, but that they preced-
by Dr Wat- ed ^hc greater, the more numerous, and more accurate
fon and his experiments of the Engliih. The names of the Eno--
ailociates. lifh gentlemen, animated with a truly philofophical
fpirit, and who wTere indefatigable in this bufinefs, de-
ferve to be tranfmitted to pofterity.
The principal agent in this fcene was Dr Watfon.
He planned and direfted all the operations, and never
failed to be prefent at every experiment. His chief
afliflants were Martin Folkes, Efq. prefident of the
Royal Society, Lord Charles Cavendifh, Dr Bevis,
Mr Graham, Dr Birch, Mr Peter Daval, Mr Tremb-
ley, Mr Elliot, Mr Robins, and Mr Short. Many
other perfons, and fome of diflin£tion, gave their attend¬
ance occafionally.
Dr .Watfon, who wTrote the hiflory of their proceed¬
ings, in order to lay them before the Royal Society,
begins by obferving (what was verified in all their ex¬
periments) that the eleftric fliock is not, ftriAly fpeak-
ing, conduaed in the fliorteft manner poflible, unlefs
.the bodies through which it paffes, condua equally
•well; for that, if they condua unequally, the circuit is
always formed through the befl conduaors, though
the length of it be ever fo great.
R I C I T Y. Paitlll.
The firft attempt thefe gentlemen made, was to con-Punciplesof
vey the elearic fliock acrofs the river Thames, making E'eflridty
ufe of the water of the river for one part of the chain of |lluRrilted
communication. This they accompliftied on the 14th ^ent”"
and iSth of July of 1747, by faftening a wrire all along 1 y—1
Weftminfter bridge, at a confiderable height above the
wrater. One end of this wTire communicated with the
coating of a charged phial, the ether being held by an
obferver, who in his other hand held an non rod,
which he dipped into the river. On the oppofite fide
of the river flood a gentleman who likewife dipped an
iron rod in the river with one hand, and in the other
held a wire, the extremity of which might be brought
into contaft with the wire of the phial.
Upon making the difeharge, the fliock was felt by
the obfervers on both fides of the river, but more fenfi¬
bly by thofe who were ftationed on the fame fide with
the machine 5 part of the ele&ric fire having gone
from the wire down the moift ftones of the bridge,
thereby making feveral fliorter circuits to the phial,
but ftill all palling through the gentlemen who were
ftationed on the fame fide with the machine. This was,
in a manner demonftrated by fome perfons feeling a
fenfible ftiock in their arms and feet, who only happen¬
ed to touch the wire at the time of one of the dif-
charges, when they were Handing upon wet fteps which
led to the river *. * pm
Upon this and the fubfequent cccafions, the gentle- ‘Tranf. Abr.
men made ufe of wires, in preference to chains, for this,vo^ x’
among other reafons, that the ele&ricity which w7asP‘,345’&c’
conduced by chains, was not fo ftrong as that conduc¬
ed by w ires. This, as they well obferved, was occafion-
ed by the junCures of the links not being fufliciently
clofe, as appeared by the flaftiing and fnapping at every
jun&ure, where there wras the leaft feparation. Thefe
lefier fnappings being numerous in the whole length of
a chain, very fenfibly leffened the great difeharge at the
prime conduclor.
Their next attempt was to force the eleCrical fliock
to make a circuit of two miles, at the New-river at
Stoke Newington. This they performed on the 24th
of July 1747, at twro places; at one of which, the
dill ance by land was 800 feet, and by w7ater 2000 : in
the other the diftance by land was 2800 feet, and by
water 8000. The difpofition of the apparatus wras fimi¬
lar to what they before ufed at Weflminfler bridge,
and the effeft anfwered their utmoft expeCations.
But, as in both cafes, the obfervers at both extremities
of the chain, which terminated in the water, felt the
fliock, as w7ell w7hen they flood with their rods fixed in¬
to the earth 20 feet from the water, as when they w7ere
put into the river; it occafioned a doubt, whether the
ftiock w/as formed through the windings of the river,
or a much fliorter w7ay by the ground of the meadow :
for the experiment plainly fliewed, that the meadow
ground, with the grafs on it, conduCed the eleCricity
very w7ell.
By fubfequent experiments, they were fully convin¬
ced, that the eleCricity had not in this cafe been con¬
veyed by the water of the river, which was two miles
in length, but by land, where the diftance was only one
mile; in which fpace, however, the eleCric power
mull neceflarily have palled over the New-river twice,
have gone through feveral gravel pits, and a large
Hubble field f. + lb p. 360.
On
Chap. XIV. ELECT
Principles of Oa the 28th of July they repeated the experiment
Electricity the fame plage, with the following variation of cir-
illuitrated cumftances< 'J'hc iron wire was, in its whole length, fup-
^ment.n Ported by dry flicks, and the obfervers Hood upon ori-
t -yi. ,> ginal eledlrics j the ell'ecl of which was, that they felt
the {hock much more fenfibly than when the conduct¬
ing wire had lain upon the ground, and when the ob¬
fervers had flood likewife upon the ground, as in the
former experiment.
Afterwards, every thing remaining as before, the ob¬
fervers were direfted, inftead of dipping their rods into
the water, to put them into the ground, each 150 feet
from the -water. They were both fmartly llruck,
though they were diftant from each other above 500
feet.
The fame gentlemen, pleafed with the fuccefs of
their former experiments, undertook another, the ob¬
ject of which was to determine, whether the ele£lric
power could be conveyed through dry ground ; and at
the fame time to carry it through water to a greater di-
flance than they had done before. For this purpofe they
pitched upon Highbury-barn, beyond Iflington, where
they carried it into execution on the 5th of Auguft
1747. They chofe a flation for their machine almofl
equally diftant from two other ftations for obfervers,
upon the New-river, which were fomewhat more than a
mile afunder by land, and two miles by water. They
had found the ilreets of London, when dry, to conduct
very llrongly, for about 40 yards ; and the dry road
at Newington about the fame diftance. The event of
this trial anfwered their expectations. The eleClric fire
made the circuit of the water when both the wires and
the obfervers were fupported on original eleftrics, and
the rods dipped into the river. They alfo both felt
the fhock, when one of the obfervers was placed in a
dry gravelly pit, about 300 yards nearer the machine
than the former ftation, and 100 yards diftant from the
river; from which the gentlemen were fatisfied, that
the dry gravelly ground had conducted the eleClricity
as ftrongly as water.
The laft attempt of this kind which thefe gentlemen
made, and which required all their fagacity and addrefs
in the conduCl of it, was to try whether the eleftric
{hock was perceptible at twice the diftance to which
they had before carried it, in ground perfectly dry, and
where no water was near, and alfo to diftinguiih, if
poflible, the comparative velocity of eleClricity, and of
found.
For this purpofe they fixed upon Shooter’s-hill, and
made their firft experiment on the 14th of Augult
1747, a time, when, as it happened, but one Ihower
of rain had fallen during five preceding weeks. The
wire communicating with the iron rod, which made
the difcharge, w^as 6732 feet in length, and was fup¬
ported all. the wTay upon baked fticks j as was alfo the
wire which communicated with the coating of the phial,
vvhich rvas 3868 feet long, and the obfervers were
dillant from each other two miles. The refult of the
explofion demonftrated, to the fatisfaClion of the gentle¬
men prefent, that the circuit performed by the elec¬
tricity was four mile's, viz. two miles of wire,
and two of dry ground, the fpace between the ex¬
tremities of the wires, a diftance, which, without trial,
as they juftly obferved, wras too great to be credited.
A gun was difcharged at the inftant of the explofion.
Vol. VII. Part II.
R I C I T Y.
7.37
and the obfervers had flop watches in their hands, to Principles of
note the moment when they felt the {hock j but as far kjeftricify
as they could diftinguifh, the time in which the eleClric ^,Uexp»ri-
power performed that vaft circuit was inftantanecus. ment.
In all the explofions where the circuit was made of —v——'
any confiderable length, it was obferved, that though
the phial was very well charged, yet that the fnap at
the gun-barrel made by the explofion was not near fo ♦
loud as when the circuit was formed in a room ; fo
that a byftander, fays Dr Watfon, would not imagine,
from feeing the flalh and hearing'the report, that the
ftroke, at the extremity of the conducing ware, would
have been confiderable, the contrary of which, when
the wires were properly managed, he fays, always hap¬
pened.
Still the gentlemen, unwearied in thefe purfuits,
were defirous of afcertaining, if pofiible, the abfolute
velocity of electricity though a certain fpace ; becaufe,
though in the laft experiment, the time of its progrefs
was certainly very fmall, they were defirous of knowing,
fmall as that time might be, whether it was meafurable,
and Dr Watfon had contrived an excellent method for
that purpofe.
Accordingly, on the 5th of Auguft 1748, the gentle¬
men met for the laft time, at Shooter’s-hill when it
was agreed to make an eledhric circuit of two miles, by
feveral turnings of the wire, in the fame field. The
middle of this circuit they contrived to be in the fame
room with the machine, where an obferver took in each
hand one of the extremities of the wires, each of which
was a mile in length. In this excellent difpofition of
the apparatus, in which the time between the explofion
and the fliock could be obferved with the greateft ex-
adlnefs, the phial was difcharged feveral times ; but the
obferver always felt himielf {hocked at the very inftant
of making the explofion. Upon this the gentlemen
were fully fatisfied, that through the whole length .
this wire, whicli was 12,276 feet in length, the velo-vJ|a^ r*
city of the eledlric power was xnftantaneous *.
We have noticed the increafed evaporation from li-How to
quids by means of eleclricity. The following experi-h>m fer¬
ment, which is commonly exhibited by ledturers on |nS'dV£lx'n“
eledlricity, is ufually confidered of the fame kind.
Stick a fmall piece of fealing-wax on the end of a
wire, and fet fire to it. Then put an eledlrical ma¬
chine in motion, and prefent the wax juft blown out at
the diftance of fome inches from the prime condudlor.
A number of extremely fine filaments will immediately
dart from the fealing wax to the condudlor, on which
they will be condenfed into a kind of net-work, refem-
bling wool.
If the wire with the fealing-wax be ftuck into one
of the holes of the condudlor, and a piece of paper be
prefented at a moderate diftance to the wax, juft after
it has been ignited, on fetting the machine in motion, a
network of wax will be formed on the paper. The
fame eftedl, but in a {lighter degree, will be produced,
if the paper be brilkly rubbed with a piece of elaftic
gum, and the melting fealing-wax be held pretty near
the paper immediately after rubbing.
If the paper thus painted, as it were, with fealing.
wax, be gently warmed by holding the back of it to the
fire, the wax will adhere to it, and the refult of the
experiment will thus be rendered permanent.
A beautiful experiment of the fame nature is made
5 A with
738 ELECT
Principles of With camplioi*. A fpoon holding a piece of lighted
Hlu^ratcd camP^or ]nac'e 1:0 communicate with an eledlrified
by ex peri- kocty as prime condu&or of a machine, while the
ment. condudor continues ele&rified by keeping the machine
v-‘—-v—in motion, the camplior will throw out ramilications,
•p 2^]. anc^ aPpcar to Ihoot like a vegetable.
camphor6 ^°on a^ter t^le difcovery of the eleftrophorus by
fhoc: into Signior Volta, an experiment was made with that in-
ramifica- Ifrument by Profelfor Lichtenberg of Gottingen, that
tions. attradfed confiderable notice. It is thus defcribed by
Curious x ^ava^°*
periment of elecfrophorus, that is, a plate of fome refmous
Profeffor fubllance, as fulphur, rofin, gum-lac, &c. is firfl: ex-
Lichten- cited, either by rubbing or otherwife; then a piece of
keig* metal of any fhape, at plealure, as for inftance, a three-
legged compafs, a piece of brafs tube, or the like, is
let upon the eledtrophorus, and to this piece of metal,
fo placed, a fpark is given, of the eledlricity contrary
fo that of the plate ; this done, the piece of metal is
removed, by means of a flick of fealing-wax or other
eledlric, and fome powder of rofin, kept in a linen bag,
is lhaken upon the eledfrophorus : this powder will be
found to fall about thofe points upon the plate, which
the piece of metal touched, forming fome radiated ap¬
pearances, much like the common reprefentations of
liars ; at the lame time, upon the greatefi: part of the
plate, that is, befides thofe liars, there is hardly any
powder at all. Now, it is to be remarked, that if the
plate be excited negatively, and the fpark given to the
metal fet upon it is pofitive, the appearance will be as
above defcribed; but if, on the contrary, the plate is
pcfitive and the fpark is negative, then the powder of
lofin wrill be found to fall upon thofe parts of the plate
which in the other cafe is left uncovered, and to leave
the liars clean ; in Ihort, it will do juft the reverfe of
what it did in the other cafe ; or, in other words, the
powder of rofin will be attradled by thofe parts only
- of the eledlrophorus which are eledlrified pofitively.
Method of The configurations produced in the above experi-
producing nient of M. Lichtenberg appeared fo curious that they
various con-were poon imjtatecj gy varlous eledtricians, particularly
byele&H- ^7 Cavallo and the Reverend Abraham Bennet,
city. inventor of the doubler. The diredlions given by this
lall gentleman are as follows.
To make red figures, take a pound of rafped Brazil
■wood : put it into a kettle with as much water as will
cover it, or rather more; alfo put in about an ounce of
gum arabic and a lump of alum about as big as a large
nut ; let it boil about two hours, or till the water is
ftrongly coloured ; ftrain off the extradl into a broad
dilh, and fet it in an iron oven, where it is to remain
till all the water be evaporated, which with me was
effedled in about twelve hours ; but this depends on the
heat of the oven, which ftiould not be fo hot as to en¬
danger its burning. Sometimes I have boiled the
ft rained extradl till it was confiderably infpifiated before
it was placed in the oven, that it might be fooner dry.
When it is quite dry but not burnt, fcrape it out of
the dilh, and grind it in a mortar till it be finely pul¬
verized. In doing this, it is proper to cover the mor¬
tar with a cloth, having a hole through to prevent the
powder from flying away and offending the nofe, and
alfo to do it out of doors if the weather be dry and calm,
that the air may carry away the powder neceffarily
efcaping, and which otherwife is very difagreeable.
E I C t T Y. Part III.
When ground fine, let it be lifted through mufiin or a Principles cf
fine hair-fieve, returning the coarfer part into the mor- Lk-dricity
tar to be ground again. When the grinding and lift- ’^uprated
ing are finilhed, the powder is ready for ufe. The re- cxi;eia“
finous plate I have moftly ufed was compofed of five > i
pounds of rofin, half a pound of bees-wax, and two
ounces ol lamp-black, melted together, and poured up¬
on a board fixteen inches fquare, with ribs upon the
edges at leaft half an inch high, to confine the com-
pofition whilft fluid : thus the refinous plate was half
an inch thick, which is better than a thinner plate, the
figures^ being more diftindl. After the compofition is
cold, it wall be found covered with fmall blifters,
which may be taken out by holding the plate before
the fire, till the furface be melted, then let it cool
again, and upon holding it a fecond time to the fire,
more blillers will appear ; but by thus repeatedly heat¬
ing and cooling the furface, it wall at laft become per-
fedlly fmooth. Some plates were made fmaller, and
the refinous compofition confined to the form of an el-
lipfis, a circle, or efcutcheon, by a rim of tin half an
inch broad, and fixed upon a board.
I he next thing to be done is to prepare the paper,
which is to be foftened in wTater, either by laying the
pieces upon each other in a veflel of cold water, or firft
pouring a little hot water upon the bottom of a large
dilh, then laying upon it a piece of paper, fo that one
edge of the paper may lie over the edge of the dilh, to
remain dry, that it may afterwards be more conve¬
niently taken up. Then pour more hot water upon its
upper furface. Upon this place another piece in the
fame manner, again pouring on more water, and thus
proceed till all the pieces are laid in. By ufing hot
water, the paper will be more foftened in a few mi¬
nutes than if it remains in cold water a wdiole day.
When the figures are to be made, the refinous plate
mult lie horizontally, whilft the eledlricity is communi¬
cated, if the experiment requires any thing to be placed
upon the plate : but it is convenient afterwards to hang
it up in a vertical pofition whilft the powder is projedl-
ed, left too much powder Ihould fall wdiere it is not re¬
quired.
A little of the powTder may be taken between a
finger and thumb, and projedled by drawing it over a
brufti; or, which is better, a quantity of powder may be
put into the bellows and blown towards the plate.
When the figure is fufficiently covered with powder,
let the plate be again laid horizontally upon a table ^
then take one of the foftened papers out of the w7ater
by its dry edge, and lay it carefully betwxen the leaves
of a book, prefling the book together, and let it lie in
this fituation about half a minute. Then remove the
paper to a dry place in the book, and prefs it again
about the fame time, which will generally be fufficient
to take off the fuperfluous moifture. Then take up the
paper by the tw7o corners of its dry edge, and place the
wet edge a little beyond the figure on the refinous plate,
lowering the reft of the piece gradually till it covers
the figure without Aiding ; then lay over it a piece of
clean dry paper, and prefs it gently; let it remain a
fhort time, and then rub it Gofer to the plate with a
cloth, or, which is better, prefs it down by means of a
w7ooden roller covered writh cloth, taking care that the
paper be not moved from its firft pofition. WThen the
paper is fufficiently preffed, let it be taken up by its
i Bennet's
new Expe¬
riments.
Cl lap. XIV. ELECT
principles of dry edge, and laid upon the furface of a veiTel of water
Electricity t}ie printed fide downwards; by this means the
rlluftrated fUperfluous powder will fink in the water, and the
^ment.ri~ figure will not be fo liable afterwards to fpread in the
iu-1^ J paper. After the paper has remained on the water
during a few minutes, take it up and place it between
the leaves of a book, removing it frequently to a dry
place. If it be defired that the paper ihould be fpeedi-
ly dry, let the book-leaves in which it is to be placed
be previoufly warmed, and by removing it to feveral
places it will be dry much fooner than by holding it
near a fire, and without drawing the paper crooked.
By the above procefs, it is obvious, that leather, calli-
co, or linen, as wTell as paper, may be printed with
thefe figures, and the effefts of the diffufion of ele&ri-
city upon a refinous plate be exhibited to thofe who
have not leifure or inclination to perform the experi¬
ments f.
The figures reprefented in Plate CXCII. wrere form¬
ed much after Mr Bennet’s method.
The apparatus ufed for making them confided only
of a common Leyden phial, and a plate of glafs 15
inches fquare, covered on one fide with a varniih of
gum-lac diffolved in fpirit of wine, and feveral times
laid over. The other fide is covered with tin-foil laid
on with common pafte. When it is to be ufed, the
glafs plate is put upon a metallic ftand, with the tin-
foiled fide laid undermoft ; the phial is to be charged,
and the knob drawn over the vamifhed fide. Thus any
kind of figure may be drawn, or letters made, as repre¬
fented in the plate; and from every figure beautiful
ramifications will proceed, longer or fliorter according
to the flrength of the charge. On fome occafions,
howrever, the charge may be too ftrong, particularly
where w-e wifh to reprefent letters, fo that the whole
will be blended into one confufed mafs. The round
figures are formed by placing metallic rings or plates
upon the electrical plate ; and then giving them a fpark
from the eleftrified bottle, or fending a fhock through
them. The figures may be rendered permanent by
blowing off the loofe chalk, and clapping on a piece of
black-fized paper upon them j or if they are wanted
of another colour, they may eafily be obtained by
means of lake, vermilion, rofe-pink, or any of the ordi¬
nary colours ground very fine. The eafieft way of ap¬
plying them feems to be by a barber’s puff bellows.
We (hall conclude this part of our article with no¬
ticing the effects produced by electricity on magnetic
needles.
Thefe may be ftated in the following propofition.
Wn electric Jhock communicates a magnetic power
to needles, and frequently reverfes or defrays that pola¬
rity.
By eleCtricity Dr Franklin frequently gave polarity
to needles and reverfed them at pleafure. A (hock
from four large jars, fent through a fine fewing needle,
he fays, gave it polarity, fo that it w-ould traverfe when
laid on waiter. What is molt remarkable in thefe elec¬
trical experiments upon magnets is, that if the needle,
when it was {truck, lay ealt and weft, the end which
was entered by the electric blaft pointed north j but
275
Experi¬
ments on
the effect
produced
by slcdtri-
city on
magnetic
needles,
277
by Dr
Franklin.
R I C I T Y. 739
that if it lay north and fouth, the end 'which lay to-Principles of
wards the north w'oukl continue to point north,
whether the fire entered at that end or the contrary ; ^ es^efj_
though he imagined that a ftronger ftroke would have ment.
reverfed the poles even in that fituation, an effect which 'v"*—’
had been known to have been produced by lightning.
lie alfo obferved, that the polarity -was ftrongeft when
the needle w'as {truck lying north and fouth, and weak-
eft wdren it lav eaft and wTeft. He takes notice that,
in thefe experiments the needle, in iome cafes, would be
finely blued like the fpring of a watch, by the eleCtric
flame \ in which cafe, the colour given by a flafu from
two jars only might be wiped off, but that a flafti from
four jars fixed it, and frequently melted the needles. * Franklins
The j ars which the doftor ufed held feven or eight gal- Litters.
Ions, and w7ere coated and lined wfith tin-foil 27S
Dr Van Marum made feveral experiments on com-ky Van
municating polarity to needles with his very powerful
machine. He and his coadjutor tried to give polarity
to needles made of wratch fprings from three to fix
inches in length, and likewife to Iteel bars nine inches
long, from a quarter of an inch to half an inch broad,
and about a line in thicknefs. The refult was, that
when the bar or needle wras placed horizontally in the
magnetic meridian, whichever wTay the fhock entered,
the end of the bar that flood tow'ard the north acquired
the north polarity, or the powrer of turning towards the
north wdien freely fufpended, and the oppoiite end ac¬
quired the fouth. If the bar, before it received the
fhock, had fome polarity, and wras placed wfith its poles
contrary to the ufual diredlion, then its natural polarity
wTas always diminifhed, and often reverfed ; fo that
the extremity of it, which in receiving the fliock look¬
ed towards the north, became the north pole, &c.
When the bar or needle was ftruck Handing perpen¬
dicularly, its loveft end became the north pole in any
cafe, even when the bar had fome magnetifm before,
and wras placed with the fouth pole dowmwards. Cce¬
teris paribus, the bars feemed to acquire an equal de¬
gree of magnetic power, whether they wTere flruck
whilft Handing horizontally in the magnetic meridian,
or perpendicular to the horizon.
When the bar or needle wTas placed in the magnetic
equator, whichever way the {hock entered, it never
gave it any magnetifm •, but if the fliock wTas given
through its width, then the needle acquired a confider-
able degree of magnetifm, and the end which lay to-
w-ards the -.eft became the north pole, and the other
end the fouth pole.
If a needle or bar, already magnetic, or a real mag¬
net, was ftruck in any diredftion, its power was always
diminiihed. For this experiment, they tried confider-
ably large bars, one being 7,08 inches long, 0,26
broad, and 0,05 thickr
When the Ihock was fo ftrong in proportion to the
fize of the needle, as to render it hot, then the needle
generally acquired no magnetifm at all, or very little.
Thefe experiments wTere made wfith the extraordinary
power of a battery compofed of 135 phials, containing
among them about 130 fquare feet of coated furface.
$ A 2
PART IV,
ELECTRICITY.
740
Theory of
Electricity,
PART IV.
I
THEORY OF ELECTRICITY.
Part IV.
Theory of
Eledtricity.
Chap. I. A Concife View of the Principal Theories
of Electricity.
Sect. I. Of the Theories of EleBricity before the Time
of Franklin.
^79
Theory of THE firfl; ele&ricians fuppofed, that ele&rical at-
the early tra&ion was performed by means? of un&uous effluvia
electricians, emitted by the excited ele&ric. Thefe were fuppofed
to attach themfelves to all bodies, and to carry back
with them thofe which were not too heavy. For in
that age of philofophy all effluvia were fuppofed to re¬
turn to the body from which they had been emitted,
fince no perfon could otherwife account for the fubltance
not being fenfibly wafted by the conflant emiffion.
When thefe light bodies, on which the un&uous efflu¬
via had faftened, had arrived again at the excited elec¬
tric, a frefh emiffion of the effluvia was fuppofed to
carry them back again. But this elfedt of the effluvia
was not thought of, till ele&rical repuliion had been
Efficiently obferved.
When the Newtonian philofophy had made feme
progrefs, and the extreme fubtility of light, and other
effluvia of bodies, was demonllrated, fo that philofo-
phers were under no apprehenfion of bodies being waft¬
ed by continual emiffion, the doclrine of the return of
effluvia was univerfally given up, as being no longer
neceflary 5 and they were obliged to acquiefce in the
unknown doftrines of attraftion and repuliion, as na¬
tural properties of certain bodies, the unknown caufe
280 of which they fcarcely attempted to explain.
Hypothefis Early in the 18th century, M. du Faye difeovered
® that there were two ftates of eleftricity, or, as he fup¬
pofed, two difterent kinds of eleftricity, produced when
different eleftrics were excited. “ Chance (fays he)
has thrown in my rvay a principle, which calls a new
light upon the fubjeef of ele&ricity. The principle is,
that there are two difthnft kinds of eletftricity, very dif¬
ferent from one another ; one of which I call vitreous,
the other refinous electricity. The iirft is that of glafs,
rock cryftal, precious ftones, hairs of animals, wool, and
many other bodies. The fecond is that of amber,
copal, gum-lac, filk, thread, paper, and a vaft number
of other fubftances. The charaCteriftics of thefe two
eleClricities are, that they repel themfelves, and attract
each other. Thus a body poffeffed of the vitreous elec¬
tricity, repels all other bodies poffeffed of the vitreous,
and on the contrary, attraCls all thofe poffeffed of the
refinous eleClricity. The refinous alfo repels the re¬
finous, and attracts the vitreous. From this principle
one may eafily deduce the explanation of a great num¬
ber of other phenomena 5 and it is probable that this
truth will lead us to the difeovery of many other
things.”
This difeovery of M. du Fay was the origin of a
theory of eleClricity, which is commonly called the
theory of two f uids, and which we lhall prefently con-
fider more at length.
Hitherto attraction andrepulfion were the only elec- 281
trical phenomena which had been obferved 5 and to the
explanation of thefe, the above general theories ap¬
peared fufficiently competent. But when eleClricity
began to Ihew itfelf in a greater variety of appearances,
and to make itfelf fenfible to the fmell, the fight, the
touch and the hearing ; when bodies were not only at¬
tracted and repelled, but made to emit ftrong fparks of
fire, attended wdth a confiderable noife, a painful fen-
fation, and a ftrong phofphorical fmell, eleCtricians
were obliged to make their fyftems more complex, in
proportion as the faCts accumulated. It was then ge¬
nerally fuppofed that the eleCtric powder, which now
began to affume the name of the eleBric fluid, was the
fame wdth the chemical principle of fire *, though fome
thought it was a fluid flu generis, which very much re-
fembled that of fire 5 and others, w ith M. Boulanger at
their head, thought that the eleCtric fluid was nothing
more than the finer parts of the -atmofphere, which
crowded upon the furfaces of eleCtric bodies, when the
groffer parts had been driven awTay by the friCtion of
the rubber. ^
During this time, it was imagined, that the eleCtric Eledtric
matter was produced from the eleCtric body by fric- matter dif-
tion ; but by a difeovery of Dr Watfon’s, it became covered to
univerfally believed, that the glafs globes and tubes ^me
ferved only to fet the fluid in motion, and by no means
to produce it. He was led to this difeovery by ob-
ferving, that, upon rubbing the glafs tube, while he
was Handing upon cakes of wax or rofin (in order, as
he expeCted, to prevent any difeharge of the eleCtric
matter upon the floor), the powder was, contrary to his
expectation, fo much leffened, that no fnapping could
be obferved upon another perfon’s touching any part
of his body 5 but that, if a perfon not eleCtrified held
his hand near the tube while it was rubbed, the fnap¬
ping was very fenfible. The event was the fame when
the globe wras whirled in fimilar circumltances. For,
if the man who turned the wheel, and who, together
with the machine, was fufpended upon filk, touched
the floor with one foot, the eleClric fire appeared upon
the conduClor ; but if he kept himfelf free from any
communication with the floor, little or no fire was pro¬
duced.—He obferved, that only a fpark or two would
appear between his hand and the infulated machine,
unlefs he at the fame time formed a communication
between the conductor and the floor ; but that then
there was a conftant and copious flow of the eleCtric
matter obferved between them. From thefe, and fome
other experiments of a fimilar kind, the DoCtor dif-
covered what he called the complete circulation of the
eleCtric matter. When he found, that, by cutting off
the communication of the glafs globe with the floor,
all eleCtric operations were flopped, he concluded, that
the eteCtric fluid was conveyed from the floor to the
rubber,
Chap.
and efflux.
I.' E L E C T R
Theory of rubber, and from tbence to the globe. For the fame
Ele(fflnaty.reafon> feeing the rubber, or the man who had a com-
‘ munication with it, gave no fparks but when the con-
duftor was conne£led wTith the Hoor, he as naturally
concluded, that the globe w^as fupplied from the con-
,§3 duttor, as he had before concluded that it w^as fupplied
Dr Wat- from the rubber. From all this he was at laft led to
fon’s theory f0rm a new theory of eleftricity, namely, that, in
of afflux eleftric operations, there was both an afflux of ele&ric
matter to the globe and the conduftor, and likewife an
efflux of the fame eleftric matter from them. Finding
that a piece of leaf filver was fufpended between a plate
eleftrified by the conduftor, and another communi¬
cating with the floor, he reafons from it in the follow¬
ing manner : “ No body can be fufpended in equili-
brio but by the joint aftion of two different direttions
of power 5 fo here the blaft of electric ether from the
floor fetting through it, drives the filver towards the
plate eleftrified. We find from hence, likewife, that
the draught of eleftric ether from the floor is always
in proportion to the quantity thrown by the globe
over the gun barrel (the prime conductor at that time
made ufe of), or the equilibrium by which the filver is
fufpended could not be maintained.” Some time af¬
ter, however, the Doftor retraced this opinion con¬
cerning the afflux and efflux, and fuppofed that all the
elefflric phenomena might be accounted for from the ex-
cefs or diminution of the quantity of ele&ric matter con¬
tained in different bodies. This is the theory that was
more fully explained by Franklin. It has been difputed
whether Dr Watfon or Franklin were the original con¬
triver of this theory. It is poflible that Watfon may
have formed the idea independently of Franklin 5 but
certainly to this latter able and acute philofopher is due
the merit of having framed and applied the hypothefis
of pofitive and negative eleftricity, which, writh feme
modification has been fince almoft univerfally adopted.
One great difficulty with which the firft electricians
2$4
Difficulty
concerning were embarraffed, was to afeertain the direction of the
the fluid. At firft, all eleftric powers, as we have already
eleiflric obferved, wrere fuppofed to refide in the excited globe
fluid. or glafs tube. The electric fpark therefore wras imagin¬
ed to proceed from the electrified body towards any
conductor that was prefented to it. It was never
imagined that there could be any difference in this re-
fpeft, whether it wras amber, glafs, fealing wax, or
any thing elfe that was excited. This progrefs of the
eleffric matter w?as thought to be quite evident to the
fenfes ; and therefore the obfervation of electric ap¬
pearances at an infulated rubber ocCafioned the greatelt
aftonifhment.—In this cafe, the current could not be
fuppofed to flow both from the rubber and the con¬
ductor, and yet the firft appearances were the fame.
To provide a fopply of the eleftric matter, therefore,
philofophers were obliged to fuppofe, that, nctxvith-
ffanding appearances wTere in both cafes much the
fame, the electric fluid was really emitted in one cafe
by the electrified body, and received by it in the other.
But now being obliged to give up the evidence from
fight for the manner of its progrefs, they were at a lofs,
whether, in the ufual method of elcCtrifying by excited
glafs, the fluid proceeded from the rubber to the con¬
ductor, or from the conductor to the rubber. It was,
however, foon found, that the eleCfricity at the rubber
was the reverfe of that at.the conductor,, and.in all re-
I C I T Y. 741
fpeCts the fame with that which had before been pro- Theory of
duced by the friCtion of fealing wax, fulphur, rofm, deny.
&c. Seeing, therefore, that both the eleCtricities
w ere produced at the fame time, by one and the fame
eleCtric, and by the fame friCtion, all philofophers were
naturally led to conclude, that both were modifications
of one fluid *, though in what manner that fluid was
modified throughout the immenfe variety of eleCtric
phenomena, was a matter not eafy to be determined.
On this fubjeCt the Abbe Nollet adopted the doc- Abbe Nob
trine of afflux and efflux already mentioned. He fup- ^et’s theory,
pofed, that, in all eleCtrical operations, the fluid is
throwm into two oppofite motions j that the afflux of
this matter drives all light bodies before it by impulfe
upon the eleCtrified body, and its efflux carries them
back again. He wras, however, very much embarraffed
in accounting for faCts where both thefe currents mull
be confidered 5 as in the quick alternate attraction and
repulfion of light bodies by an excited glafs tube, or
other excited eleCtric. To obviate this difficulty, he
fuppofes that every excited eleCtric, and likewife every
body to which eleCtricity is communicated, has two
orders of pores, one for the emiffion of the effluvia, and
another for the reception of them. M. de Tour im¬
proved upon Nollet’s bypothefis, and fuppofed that
there is a difference between the affluent and effluent
current j and that the particles of the fluid are thrown
into vibrations of different qualities, which makes one
of thefe currents more copious than the other, accord¬
ing as fulphur or glafs is ufed. It is impoffible, how¬
ever, that fuppofitions fo very arbitrary could be at all
fatisfaftory, or received as proper explanations of the
eleCtric phenomena.
About this time the Leyden phial was difeovered;
and the extraordinary effeCts of it rendered the in¬
quiries into the nature of the eleClric fluid much more
general than before. It would be tedious, and indeed
impoffible, to give an account of all the theories which
wTere now invented. One of the moft remarkable was
that of Mr Wilfon. According to this gentleman, the Mr Wil-
chief agent in all the operations of eleCtricity, is Sir fan’s theo-
Ifaac Newton’s ether 5 which is more or lefs denfe in T’
all bodies in proportion to the fmallnefs of their pores,
except that it is much denfer in fulphureous and unCtu-
ous bodies. To this ether are aferibed the principal
phenomena "of attraction and repulfion : the light, the
fulphureous or rather phofphoreal fmell with which
violent eleftricity is always attended, and other fenfi-
ble qualities, are aferibed to the groffer particles of
bodies driven from them by the forcible action of this
ether. He alfo endeavours to explain many eleCtrical
phenomena by means of a fubtile medium at the fur-
face of all bodies ; which is the caufe of the refraCtion
and reflection of the rays of light, and alfo refifis the
entrance and exit of this ether. This medium, he; fays,.
extends to a fmall diitance from the body, and is of the
fame nature with what is called the eleBric fluid. On
the furface of conductors this medium is rare, and eafi-
ly admits the paffage of the eleCtric fluid ; whereas, on.
the furface of eleCtrics, it is denfe and relifls it. The
fame medium is rarefied by heat, which thus changes
conductors into non-conduCtors. By far the greater
number of philofophers, howrever, rejeCted the opinion
of Pvlr Wilfon ; and as they neither chofe to allow the
electric fluid to be five nor ether, they were obliged to
own ■
^42
ELECT
Eledb-' city" ^ tha1t ^ Was a fluid Mgeneris, i. e. one of whofe
i nature they were totally ignorant.
387
S:XT- If* Of the Theory of P of the and Negative
Eleciricity.
t)r Frank- _ According to this theory, all the operations of elec-
t ieoiy. tricity depend upon one fluid fit generis, extremely fub-
tile and elallic. Between the particles of this fluid
there fubfifts a very flrong repulfion with regard to
each other, and as ftrong an attraftion with regard to
other matter. Thus, according to Dr Franklin’s hy-
pothefis, one quantity of eleftric matter will repel ano¬
ther quantity of the fame, but will attraa and be at¬
tracted by any terreflrial matter that happens to be near
it. The pores of all bodies are fuppofed to be full of
this fubtile fluid 5 and when its equilibrium is not dif-
turbed, that is, when there is in any body neither more
nor lets than its natural fliare, or than that quantity
which it is capable of retaining by its own attraction,
the fluid does not manifeft itfelf to our fenfes. The ac¬
tion of the rubber upon an electric diilurbs this equili¬
brium, occafioning a deficiency of the fluid in one place,
and a redundancy of it in another. This equilibrium
being forcibly difturbed, the mutual repulfion of the
particles of the fluid is neceffarily exerted to reilore it.
lr two bodies be both of them overcharged, the electric
atmofpheres repel each other, and both the bodies re¬
cede from one another to places where the fluid is lefs
denfe. For as there is fuppofed to be a mutual at-
- traction between all bodies and the electric fluid, fuch
bodies as are electrified muft go along with their at¬
mofpheres. If both the bodies are exhaufted of their
■natural fhare of this fluid, they are both attracted by
the denfer fluid exiting either in the atmofphere con-
rtiguous to them, or in other neighbouring bodies ;
which occaflons them till to recede from one another
*■288 as they were overcharged.
Difficulty This is the Franklinian doctrine concerning the caufe
concerning of electric attraction and repulfion ; but it is evident,
why bodies ^le re?‘^OT1 j11^ now given why bodies negatively
negatively attracted ought to repel one another, is by no means
electrified fatisfactory. Dr Franklin himfelf had framed his hy-
repei one pothefis before he knew that bodies negatively electri-
anot ier. fjecj would repel one another; and when he came af¬
terwards to learn it, he was furprifed, and acknow-
7 cturs>:!‘n 1 ledged that he could not fatisfactorily account for it *.
‘ Other philofophers therefore invented different folu-
Different tiems of this difficulty, of which that above mentioned
folutions. is one. But by fome this was rejefted. They faid,
of this dif- that as the denfer eledlric fluid, furrounding two bo-
CU ty dies negatively electrified, acts equally on all fides of
thofe bodies, it cannot occafion their repulfion. The
repulfion, according to them, is owing rather to an
accumulation of the electric on the furfaces of the two
bodies 5 which accumulation is produced by the at¬
traction, and the difficultv the fluid finds in entering
them. This difficulty is fuppofed chiefly to be owing
to the air on the furface of bodies, which Dr Prieflley
fays is probably a little condenfed there. This he de¬
duces from an experiment of Mr VVilfon, corrected by
M' ' nt.oii The experiment was made in order to
ob:■ >%.• •'■vie of the electric light through a Tor-
\ lingular appearance of light was
rice
ch'j
quickfilver, at which
RIG I T Y. part IV.
the fluid was fuppofed to enter. Mr Wilfon fuppofed Theory of
that this was owing to a fubtile medium fpread over Electricity,
the iunace of the quickfilver, and which prevented v_ *
the eafy entrance of the electric fluid. But this was
afterwards difeovered by Mr Canton to be owing to
a fmall quantity of air which had been left in the tube.
It is plain, however, that as the attraction is equal
a4 round, and likewife the difficulty with which the
fluid penetrates the air, bodies negatively electrified
ought not to repel one another on this fuppofition
more than the former. Nay, they ought to attract
each other ; becaufe, in the place of contact, the refift-
ance of the air would be taken off, and the electric
fluid could come from all other quarters by the attrac¬
tion of the bodies.
This theory is evidently no folution of the difficul- Infufficient.
ty j feeing it is only explaining one fact by another,
which requires explanation at leaf! as much as the firff.
We ffiall fee hereafter how this difficulty may be ex¬
plained.
What gave the greateft reputation to Dr Franklin’s Dr Frlnk-
theory, was the eafy folution which it afforded of the lin’s expla-
phenomena of the Leyden phial. The fluid is fuppofed nation of
to move with the greateft eafe in bodies which are con- ^gna^T^e
ductors, but with extreme difficulty in electrics per fe; Leyden 1 C
infomuch that glafs is abfolutely impermeable to it. It phial,
is moreover fuppofed, that all eleeftrics, and particular¬
ly glafs, on account of the fmallnefs of their pores, do
at all times contain an exceeding great, and always an
equal quantity of this fluid 5 fo that no more can be
thrown into any one part of any dedtric fubftance, ex¬
cept the fame quantity go out at another, and the gain
be exadtly equal to the lofs. Thefe things being pre-
vioufly fuppofed, the phenomena of charging and dil-
charging a plate of glafs admit of an eafy folution.
In the ufual manner of eledtrifying by a Imooth glafs
globe, all the eledtric matter is fupplied by the rub¬
ber from all the bodies which communicate with it.
If it be made to communicate with nothing but one
of the coatings of a plate of glafs, while the conduc¬
tor communicates with the other, that fide of the glafs
which communicates with the rubber muft neceffarily
be exhaufted in order to fupply the condudtor, which
muft convey the whole of it to the fide with which it
communicates. By this operation, therefore, the elec¬
tric fluid becomes almoft entirely exhaufted on one fide
of the plate, while it is as much accumulated on the
other 5 and the difeharge is made by the eledtric fluid
rufliing, as foon as an opportunity is given it by means
of proper condudtors, from the fide which was over¬
loaded to that which is exhaufted.
It is not, however, neceffary to this theory, that the
very fame individual particles of eledlric matter which
were thrown upon one fide of the plate, ihould make
the whole circuit of the intervening condudlors, efpe-
cially in very great diftances, fo as adlually to arrive
at the exhaufled fide. It may be fufficient to fuppofe,
that the additional quantity of fluid difplaces and occu¬
pies the fpace of an equal portion of the natural quan¬
tity of fluid belonging to thofe condudtors in the cir¬
cuit which lay contiguous to the charged fide of the
glafs. This difplaced fluid may drive forwards an
equal quantity of the fame matter in the next conduc¬
tor ; and thus the progrefs may continue till the ex¬
haufted fide of the glafs is fupplied by the fluid natu-
rally
Chap. I. ELECT
Theory of rally exifling in the conductors contiguous to it. In
Electricity, this cale, the motion of the eleftric fluid, in an explo-
'““■""V 1 lion, will rather refemble the vibration of the air in
founds, than a current of it in winds.
It will foon be acknowledged (fays Dr Prieftley),
that while the fubftance of the glafs is fuppofed to
contain as much as it can poflibly hold of the eleftric
fluid, no part of it can be forced into one of the
fides, without obliging an equal quantity to quit the
other fide : but it may be thought a difficulty upon
this hypothefis, that one of the fides of a glals plate
cannot be exhaufted, without the other receiving
more than its natural {hare *, particularly, as the par¬
ticles of this fluid are fuppofed to be repuliive of one
another. But it muff be confidered, that the attrac¬
tion of the glafs is fufficient to retain even the large
quantity of eleftric fluid which is natural to it, againit
all attempts to withdraw it, unlefs that eager attrac¬
tion can be fatisfied by the admiffion of an equal
quantity from fome other quarter. When this oppor¬
tunity of a fupply is given, by connefting one of the
coatings with the rubber, and the other with the con¬
ductor, the two attempts to introduce more of the
fluids into one of the fides are made, in a manner, at
the fame inflant. The aftion of the rubber tends to
dillurb the equilibrium of the fluid in the glafs 5 and no
fooner has a fpark quitted one of the fides, to go to
the rubber, than it is fupplied by the conductor on the
other 5 and the difficulty with which thefe additional
particles move in the fubrtance of the glafs, effectually
prevents its reaching the oppofite exhaufted fide. It is
not faid, however, but that either fide of the glafs may
give or receive a fmall quantity of the eleCtric fluid,
without altering the quantity of the oppofite fide. It
is only a very confiderable part of the charge that is
meant, when one fide is faid to be filled while the other
is exhaufted.
It is a little remarkable, adds Dr Prieftley, that the
eleCtric fluid, in this and in every other hypothefis,
fliould fo much refemble the ether of Sir Ifaac Newton
in fome refpeCts, and yet differ from it fo effentially in
others. The eleCtric fluid is fuppofed to be, like
ether, extremely fubtile and elaftic, that is, repulfive of
itfelf; but inftead of being, like the ether, repelled by
all other matter, it is ftrongly attracted by it: fo that,
far from being, like the ether, rarer in the fmall than
in the large pores of bodies, rarer within the bodies
than at their furfaces, and rarer at their furfaces than
at any diftance from them ; it muft be denfer in fmall
than in large pores, denfer within the fubftance of
bodies than at their furfaces, and denfer at their fur-
292 faces than at a diftance from them.
Attraction T0 account for the attraction of light bodies, and
fiomhror '"h 0l;^er eleCtrical appearances, in air of the fame denfity
with the common atmofphere, when glafs (which is
fuppofed to be impermeable to electricity) is interpo-
fed ; it is conceived, that the addition or fubtrac-
tion of the eleClric fluid, by the aCtion of the excited
eleCtric on one fide of the glafs, occafions, as in the
experiment of the Leyden phial, a fubtraCtion or addi¬
tion of the fluid on the oppofite fide. The ftate of the
fluid, therefore, on the oppofite fide being altered, all
light bodies within the fphere of its aCtion muft be af-
feCted in the very fame manner as if the effluvia of the
excited eleCtric had actually penetrated the glafs, ac-
glab ac¬
counted
for.
It I C I T Y.
743
cording to the opinions of all electricians before Dr Theory of
Franklin. EJeClricity.
This hypothefis has been greatly improved by M. "7^7
iEpinus of St Peterihurgh, and by the Hon. Henry improve-
Cavendifti; and we fliall now proceed to an illuftration ment of
of the theory as given by thefe gentlemen. Franklin’s
theory by
./Epinus
and Caven-
difli.
Theory of TEpinus.
EleCtrical phenomena are produced by a fluid of a 294
peculiar nature, which we call the Electric Fluid
which has the following properties.
1. Its particles repel each other with a force increaf-
ing as the diftances flecreafe.
2. Its particles attraCt the particles of all other mat- 295
ter with a force increafing as the diftances decreafe, and
this attraction is mutual.
3. The Electric Fluid by reafon of its extreme 296
fubtility is capable of penetrating other bodies, but all
bodies are not penetrated by it with equal facility. In
thofe bodies which we call non-elehirics, fuch as metals
and water, it moves very readily ; but in thofe bodies
which have been called eleBrics per fe, fuch as glafs,
&c. it either does not move at all, or moves with
great difficulty.
4. Every body has a certain quantity of eleSlric fluid
which is proper to it, and may therefore be called its ^
natural quantity ; this quantity is proportional to the
mafs.
5. We fay that a body is eleCIrified pofltively when
the quantity of eleCIric fluid which it has in any way
received is greater than its natural quantity ; and when
that quantity is lefs than its natural quantity, we fay
that the body is eleCIrified negatively.
6. The phenomena which depend on the aClion of 293
the eleBric fluid may be reduced to two claffes ; the firft
comprehending the cafes in which the fluid removes
from one body into another which has lefs of it j the
other thofe in which the bodies containing the fluid are
in motion, fo as to approach or recede from each other,
or fo as to attraCI and repel each other.
Such is the hypothefis of M. Hipinus \ let us now
inquire what confequences may be drawn from it.
Let us fuppofe a body to contain a certain quantity 290
of the eleCIric fluid, and let us examine the ftate of a
particle of the fluid, as P, near the furface of the body.
There is a mutual attraction between the particle P,
and the particles of matter in the body ; and there is a
mutual repulfion between it and the other particles
of eleCIric fluid in the body. The whole attrafting-
force may be equal or unequal to the whole repulfive
force. If they be equal, P is in equilibrio, and has no
tendency to motion.
Now let us fixppofe the body to have received a
quantity of fluid over and above its natural quantity }
i. e. let the body be electrified pofltively. As, while the
body was in its natural ftate, the attraCHve and repuL
five forces were in equilibrio, the increafe ol fluid will
augment the repulfive force, which will now exceed
the attraCIive force, and the particle P will be repelled
towards that furface to which it is neareft, till it at
length quits the body. The repulfive power will con¬
tinue to aCI upon other particles, which will be fuccef-
lively puflied nearer the furface, fo as to produce a con-
ftant ejjlux of the fluid till the equilibrium is re-eftablilh-
ed.
I
744
Theory of
Kleftricity.
300
-301
Saturation
defined.
302
3°3
ELECT
ed, or till the body contains no more than its natural
quantity.
Let us now conceive that the body has loft a quan¬
tity of electric fluid, or that it is electrified negatively.
The repulfive force of the fluid upon the particle P
will then be lefs than the attractive force of the mat¬
ter contained in. the body or the fame particle, this at¬
traction will begin to aCt, and the particle will move
nearer the centre. The attraction continuing to aCt,
particles near the furface, and thofe of contiguous bo¬
dies will fucceffively move towards the centre of the
body 5 or a continual influx of fluid will take place till
the equilibrium is reftored.
Definition.—When a body contains its natural
quantity of eleftric fluid, we lliall fay that it is fa-
turated.
It will be convenient for us to have general expref-
lions for thefe feveral Hates of a body, in order the bet¬
ter to eftimate the forces.
Let Q reprefent the natural quantity of fluid,
a, the attractive force of the other matter in the
body, which we fhall hereafter call Amply the
matter,
r, the repulfive force of the fluid ; and
J't the redundant or deficient fluid.
Then in the cafe in which a body is faturated, a—r
will reprefent the degree of force with which the par¬
ticle P is attracted 5 and r—a the force with which it
is repelled. But here a—r; confequently a—r and
■r—a—o.
But let the quantity fbe added to Q, and uniformly
diftributed through the body; the fluid will now be
-A-5 we muft admit the repulfive force to be
proportional to the quantity of fluid, we thall have
u:a+/=-^±p,or|+|OT:+|.
This quantity will reprefent the force with which P is
repelled by the whole fluid of the body. But it is alfo
attracted by the matter of the body, with the force a ;
the whole force exerted on P will therefore be a—r—
fr
~ but a—r—o : the whole aCtion exerted Jon P is
therefore or the force with which the particle P is
u j • fr
repelled, is —.
To conceive this more readily, we are to remember
that when the quantity of fluid ~ (T, P is in equili-
brio j it will therefore be neceflary only to confider the
aCtion of the fuperabundant fluid f. Then to find the
repulfive force of this, we fay Q : f~r : ^ as before }
but to this we muft affix the fign —, as we muft confi¬
der repulfive forces as negative, and attractive as posi¬
tive. The particle P then being repelled with this
fr • • •
force —, it will quit the body unlefs it be oppofed by
fome obftacle, and the repelling force continuing to aft
on other particles, an efflux of fluid will be produced.
The force L- will however be continually diminilhing,
but will not entirely ceafe till f—o.
.Now let the quantity of fluid /be fubtrafted from
E I C I T Y. .Part IV.
Then = r—C- ,vi!l reprefent the Sirkity.
force with which P is repelled. But it is attrafted ' ~^
with the force a; the whole aftion therefore exerted ^
fr
on P is a—r + 7T : but a—r—o; therefore the whole
fr
force = —, which reprefents the force with which P
is attrafted.
When there is a deficiency of fluid there is a pro¬
portional redundancy of matter, and vice verfa. Hence
we may deduce the following inference.
1 he production of eleClricalphenomena depends entire- 305
ly on a redundancy of fluid or a redundancy of matter. Electrical
There are two caufes which obilruft or prevent the^™^0'*
effefts which we have been deferibing; the one depend- aTedun-"
ing on the nature of the body itfelf, the other on thatdancy of
of the furrounding bodies. The firft caufe of obftruc-fluid or
tion takes place when the bodies themfelves are thofe matter*
which are called electrics per fe, in which the fluid Caufe fob-
moving with confiderable difficulty, its efflux in the firftftruding"
cafe, and its influx in the fecond, will be alike retarded, tliefe ef-
The fecond caufe afts when the furrounding bodies are tei^s*
eledrics per fe, as very dry air ; as the refiftance which
thefe oppofe to the motion of the fluid, will produce in
the efflux or the influx, a retardation fimilar to that
which arifes from the eleftric nature of the eleftrified
body. We may hence conclude that a body will con¬
tinue to exhibit eleftrical phenomena for a longer time,
cceteris paribus, according as the body itfelf, or the
bodies by which it is furrounded, approach neareft to
the nature of eleCirics per fe, whence we fee how elec¬
trics are ufeful in confining the eleftric fluid, or in in-
fulating eleftrified bodies.
The conduftors of an eleftric machine will afford a 307
familiar illuftration of the above principles as far they ftluftration‘
relate to non-eleCtrics. In the ordinary machine, in
which a cylinder is employed, the cuffiion and filk by
which the cylinder is rubbed communicate to it a por¬
tion of the fluid which they contain, the lofs of which
they fupply from the neighbouring bodies with which
they communicate, when the chain connefts the rubber
with the earth, &c. The fluid is then communicated
from the cylinder to the prime conduftor by the points
placed on the fide of it, and the conduftcr becomes
eleftrified pofilively. The glafs pillar by which the
conduftor is fupported, and which is an electric per fe,
oppofes the farther propagation of the fluid, and pre¬
vents its efcape on one fide, while the furrounding air,
if it be very dry, oppofes its efcape on the other 5 fo
that the conduftor will retain for a moment the excefs
of fluid which it has received. Now, if we prefent a
fine metallic point to the prime conduftor, a Imall lu¬
minous ftar will appear at the point; indicating, as we
have before feen, a pofitive eleftricity. This ftar is
produced by the efflux of the eleftric fluid from
the conduftor, the particles of the fluid being im¬
pelled by their mutual repulfion, and by the attraftion
of the point to approach and penetrate this, as we ftidl
more fully fee hereafter.
When the rubber is infulated, as it is perpetually
communicating a portion of its fluid to the cylinder,
without being able to procure a freffi fupply from the
furrounding bodies, it is continually acquiring a nega¬
tive
of fluid.
Plate
CXCill.
Chap. I. ELECT
Theory of tive electricity. There will now be a continual efflux
Effidtricity. 0£ from the conduflor towards the cuihion, and
^ v the conductor will, in its turn, be electrified negatively.
In this cafe, if -we prefent a fine metallic point to the
conductor, there will blue from the point a luminous
ptencil, which is produced by the efflux of fluid from
the point to the conductor, fn order to reftore the equi-
8 librium.
Efledf of an We have hitherto confidered the fluid as uniformly
finequal diffufed through the body. But it will often happen,
di.Intuition t]iat t]lere wiH be a redundancy of fluid in one part of
the body, while there is at the fame time a deficiency in
another part. In order to fimplify our formula, we
fhall fuppofe the body BC (fig. 96.) divided into two
equal parts, AB, AC, and that the fluid in AB exceeds
its natural quantity, while that in AC is lefs than the
fame quantity, the proportion of the fluid acquired on
one fide to that loft on the other being variable at
pleafure. Let us examine the fituation of two particles
P, />, placed towards the two extremities.
Let reprefent the quantity of fluid neceffary for
the faturation of AB or AC,
<7 — the attraction of the whole matter in AB
for the particle P or />,
r — the repulfton of the whole fluid uniformly
diftributed in AB on the fame particle,
r' — the repulfion of an equal quantity of fluid
in AC on the fame particle,
f ~ the quantity of redundant fluid in AB,
and g — the deficient quantity in AC.
Now the force by which the particle P or /> is at¬
tracted by the matter of BC when faturated, will be
a—r—r7, which when the body is in its natural ftate
will be equal to 0. But AB contains the redundant
fluid f and AC the deficient fluid g. The whole ac-
(ft+/)Xr
3°9
Adtion on
external
Suid.
tion exerted muft therefore be a—
(Q—g) X ^
Q.
But a—r—r'—o; therefore the whole
gr'-~fr
& ’
or rather, fince r is greater than r\
Q.
aCtion is
Jr—gd
& ’
particle P is repelled. In the fame manner,
wdiich will reprefent the force by which the
Q.
R X C X T Y. 745
conduClor, or fuch as is permeable to the fluid, its ftate Theory of
cannot be permanent till the fluid is uniformly diftribu- tUcctHcUy.
ted between the two halves, unlefs it is aCted on by
fome external force. But in a non-conduCtor, or per¬
fect eleCtric, this ftate may fubfift, and it will be con¬
tinued for a longer or a fhorter time, in proportion as
the eleCtric be more or lefs perfeCt.
If we had fuppofed the part AC to be overcharged,
inftead of AB, P wmuld have been repelled with a
/Xr-fr'
& ’
310
Action on
internal
fluid.
ftronger force, which would be reprefented by
which is evidently greater than"-———, the repulfive
force in the firft cafe. The particle /> is alfo lefs at¬
tracted than before, when AB is undercharged inftead
of AC.
The above remarks wall equally apply to the cafe of 314
two conducting bodies AB and CD, fig. 98. feparated
by an eleCtric, Z.
It is proper to obferve that the quantities f and y,
were indefinite in the above reafoning. Their value
may be fuch that the tendency to influx or efflux may
ceafe, or may be reverfed •, for fuppofing gr’—fflr—o,
or g : f—r : rJ 5 and we fhall have g~ —. In this
cafe the attraction of the redundant matter balances
the repulfion of the redundant fluid, and P is neither
attracted nor repelled. Hence we have this important
faCt, that a body may be neutral, even where it is re¬
dundant or dejicient.
When one extremity of the body is thus rendered
inactive, the ftate of the other extremity is changed.
To find this ftatc we muft put in place of its
equal g, m the formula -—^— ; and we (hall have
Again the forces may be fo balanced, that there 314
fhall he no tendency to influx at C, fig. 96. Make g—
ft* • • •
‘—q-, which expreftes the aCtion at C. The aCtion at B,
. i • fi' .
the other end, will be obtained by putting —, in place
of g in the formula ■— as before, and the refult
&
will reprefent the force by which p is attraded
Now7, let us fuppofe a particle />' in the middle of n 
the body BC j wLile the body is faturated, it will be (—tt— ), will exprefs the repelling force at B.
in equilibrio ; but as the one half of the body AB con- ' '
tains the redundant fluid f, and the half AC the defi¬
cient fluid g, the particle p' will be repelled in the di-
fr
reftion AC by the force But it is repelled in the
therefore the whole re-
direftion AB by the force 5
pulfive force by which it is impelled in the direction
A^ AC Wiube-Cisr, or^xt.
diffufion From what wre have faid above, it appears that fo
will be pro- long as there is a redundancy of fluid in AB, and a
duced it' deficiency in AC, the redundant fluid has a tendency
t!;e„re b„e.n0 to flow from A to C 5 and if the body be a perfeCt
VoLv VIL Part II,
Ubftruction.
In order, the better to conceive the relative effeCts in
each of the above cafes, we muft obferve that the re¬
pulfion of the part AB on the particle P muft increafe
in proportion as the quantity of additional fluid acquired
by AB is greater. On the other hand the attraction of
the part AC for the fame particle will increafe accord¬
ing as the quantity of fluid fubtraCted from AC is
greater. Now7, as we have fuppofed the quantities of fluid
in the two parts variable, we may fuppofe a cafe to hap¬
pen, in which, for inftance, the quantity loft by AC
may be fuch that the excefs of its attraction on P
thence refulting, may exaCtly counterbalance the di-
minifhed attraction ariftng from its great diftance,
compared to the repulfion of the part AB on the
^ 5 B ' fame
In tliis
E
cafe.
L E C T
P will remain immove-
3-1S
746
Theory of feme particle
Eleflricity. ab|e>
If, on the contrary, the quantity of fluid loft by
AC be not fufficicnt to compenfete for the greater di-
ftance, the repullion of AP will prevail over the
attraction of AC, and the particle P will quit the
body.
TL he particle p will alfo undergo certain changes in
thele different cafes. . If the particle P remain im¬
moveable, for inftance, the particle p will have a
progreffive motion towards the body A, ftnce this
is near the part AC of which the attractive force in
this cafe exceeds the repulftve force of AB. If the
particle P has already a tendency towards the body A,
the particle p will for a ftiil ftronger reafon be attracted
towards A.
In general, according to the different degrees offeree
exerted by the two parts of the body, it will happen
that the fluid will be attracted and repelled on both lides
by turns, or it will be attracted on one fide, while it is
repelled on the other, and v. v. or laftly, it may remain
immoveable on one fide, while it is attracted or repelled
on the other.
If we fuppofe that the redundancy of fluid in AB is
exaCtly equal to the deficiency in AC, then the particle
p will have a tendency to penetrate the body A, while
the particle P will be repelled by it.
To prove this, let us fuppofe that the parts AB, AC
aCt by turns on the particle p placed at a determinate
diftance 5 and let us conceive the repulfive force of the
part AB to be concentrated in a determinate point,
while the attraClive force of the part AC muft be fup-
pofed concentrated in a correfponding point on the other
fide. For, whatever be the law, in proportion to the
diftance which the repulfion of the particles of the elec¬
tric fluid follows *, the attraction of the particles of mat¬
ter in the eleftrified body ought to follow the fame
law : fince, without this, there could be no counterpoife
between the attraction and repulfion of the particles in
the natural ftate of the body. It follows then, that
the attraction exerted by AC upon the particle p muft
be equal, in the prefent cafe, to the repulfion of AB
on the fame particle. Since, on one fide, the particle is
repelled by AB by reafon of the excefs of fluid in that
part, and on the other it is attracted by AC by reafon
of the quantity of matter in that part, and which is pro¬
portional to the quantity of fluid which is fuppofed to
have paffed into AB. In the prefent cafe, therefore,
where the particle p is nearer to AC than to AB, the
attraction will prevail over the repulfion, and the par¬
ticle will penetrate to AB, and pafs through it to the
body A.
In the feme manner we might prove that the particle
P would be repelled from A.
The equilibrium between the forces of the parts
AB, AC being difturbed, it is clear that there will be
an attempt to reftore it, fo that a portion of the redun¬
dant fluid in AB will pafs into AC, till the body be
brought back to its natural ftate. The return to this
ftate will be more or lefs flow, according as the body is
a more or lefs perfeCI eleClric 5 but if it is a conduClor
_ . the fluid will pervade it in an inftant, and an equal dif-
“ic tribution will immediately take place,
tions con- ^ ^as ^een ftated that the fluid does not move with
fidered, equal facility through all bodies, but that in moving
B I C I T Y
Fart IV.
316
317
3^
through electrics it meets with more cr lefs refiftance. Theory of
It will be proper, before we proceed farther, to con- Ebdtnoty.
fider the nature of this refiftance. It may either arife y '
folely from the inertia of the particles of the fluid, which
is the cafe in a perfeCI fluid ; or it may refemble the re¬
fiftance oppofed by a parcel of grain to the defeent of
fmall foot through it, or the refiftance of a plaftic or
ductile body, fuch as clay or lead, to the motion of a
body through its pores. In the firft cafe, any inequality
of force, however fmall, is capable of producing a uni¬
form diiiribution of the fluid, or at leaft fuch a diftribu-
tion as will make the excels of the mutual attractions
and repulfions equal to the degree of external force by
which an unequal diftribution may be kept up. But in
the two laft cafes, before a particle of fluid can change
its place, it muft overcome the tenacity of the adjoinino-
particles oi the body, and, confequently, when an un¬
equal diftribution has been produced by an external
force, it will not be rendered equable by a removal or al¬
teration of that force, but. there will remain fuch an in¬
equality of diftribution, as will caufe the want of equi¬
librium between the attractions and repulfions to be
counterbalanced by the tenacity of the body.
From the different ftates of the particles P, />, as de-
feribed in the above cafes, we may conclude, that, during
the return of a body to its natural ftate, the readinels
with which the fluid flows from AB into AC muft de¬
pend much on the nature of the furreunding bodies, and
the greater or lefs facility with which thefe are pervaded
by the eledlric fluid.
If the fluid is not uniformly diftributed throughout
every part of the body, or if, though there be a uniform
ddlribution, the two parts of the body are unequal, we
Ikall always obtain refults analogous to thofe which have
been given. There is an infinity of cafes fuppofable,
relative to the different ftates of AB and AC 5 but as
each of thefe cafes has a determinate relation to the meft
fimple cafe, which we have been confidering, it may al¬
ways be reduced to this.
Let us fuppofe, for example, that the part AB is
double, triple, &c. the part AC, and that the portion
of fluid, which is fuperabundant in AB, is equal to that
which is deficient in AC : If we conceive the particle-
p fituated between thefe two parts, the point in which
we muft fuppofe the repulfive force of AB to be con¬
centrated, will not be the fame as that given in (3 15) j
but the point in which p muft be placed that it may be
attracted by AC and repelled by AB, wall be between
the centres of a ft ion of AB and AC, though not at an
equal diftance from thefe parts. Then, in the cafe where
p is nearer to the centre of aftion of AC than to that of
AB, this particle will tend to penetrate into AC,
while the particle P wall be equally repelled from it. ,7 f>
Having thus examined the aftion between the par- A&ions of
tides of fluid moving in a body, and the particles ofele<ftrical
matter in the fame body, we ftiall proceed to confider bodies on
the aftion of eleftrified bodies on each other. tac*1 otb^r'
Let there be two bodies, A and B, in the if natural
ftate.
Let M reprefent the common matter in A.
the common matter in B.
F, the fluid required to faturate A.
the fluid required to faturate B.
2;, the mutual aftion between a particle of fluid"
and the correfpondent matter. This aftion is reprefent-
ed
Chap. I. ELEC T
Theory of ed by an unknown quantity, becaufe it is indeterminate:
Eleftricity. varying with every change of diftance.
As the actions of thefe bodies on each other are re¬
ciprocal, it will be fufficient here to conlider how the
body A is alfefled. There are three circumftances to
be taken into confideration.
1. The particles of fluid in A attraft the particles of
matter in B with the force -a } fo that the whole at¬
traction of A on B will be the produft of F and m mul¬
tiplied by % or Ym « j or
xft. F tends towards m with the force -}-F m cz.
2. The particles of fluid in A repel the particles of
fluid in B with the fame force % \ fo that the whole re-
pulfion of A on B wall be F or
2d. F tends to feparate from f with the force —F^
3. The particles of matter in A are attrafted by the
particles of fluid in B with the fame force 2;, fo
that the whole attraction of B on A will be 3
or,
3d. M tends to approach f with the force -f-My's;.
The whole tendency of A to approach or to feparate
from B may therefore be reprefented by the fymbol
$s X F /ra-j-M f— F/. But as, from the hypothefis, the
attraction of the particles of fluid in A for the particles
of matter in B is equal to the repulfion between the
particles of fluid in A and the particles of fluid in B,
which are competent to the matter attracted by the fluid
in A, the attraction F m z is balanced by the repulfion
F/s. We have, therefore, only to confider the re¬
maining attraction, or the attraction of the matter ih A
for the fluid in B, or My2;. On the wdiole, therefore,
A will move towards B, and, as all aCtion is equal
and contrary, B will move towards A with an equal
320 force.
■Deficiency This would be the neceffary confequence of the hy-
in the hy- pothefis, as it Hands 3 but as we fee no attraction be-
pothefi!>iup-tween bodies in their natural ftate, there muft be fome
^ec*‘ defeCt in the hypothefis. To remedy this, Atpinus
brings another repulfive force into play, and fuppofes
that every particle of matter in A repels every particle
of matter in B, as much as it is attraded by fo much
of the fluid in B as is neceflary for its faturation. Now,
therefore, the whole aCtion exerted by B on A will be
2; X F m — Y f— M m -j- M f fo that as F m 2; is balan¬
ced by F and M ra ss by My2;, there will remain
no excefs on either fide, and conlequently the bodies will
have no tendency to motion.
iEplnus de- Great objeCtion has been made to this additional part
feuded. of M. Ahpinus’s hypothefis, and indeed Ahpinus him-
felf acknowledges, that this circumllance appeared to
him hardly admiflible 3 it feeming inconceivable that a
particle in A {ball repel a particle in B, or recede from
it eleClrically, wbile it tends toward it by planetary
gravitation. But more attentive confideration fliewed
him, that there was nothing in it contrary to the ob-
ferved analogy of natural operations. We fee innumer¬
able inftances of inherent forces of attraction and repul¬
fion 3 and nothing hinders us from’ referring this lately
difcovered power to the clafs of primitive and funda¬
mental powers of nature. Nor is it difficult to recon¬
cile this repulfion with univerfal gravitation 3 for while
bodies are in their natural ftate, the eleCtric attractions
and repullions balance each other, and .there is nothing
to difturb the phenomena of planetary grav itation ; and
R I C I T Y.
’+7
when they are not in their natural eleClrical ftate, it is Theory of
a faCl that their gravitation is difturbed. Although we Gedlricit)
cannot conceive a body to have a tendency to another
body, and at the fame time a tendency from it,
when we derive our notion of thefe tendencies entire¬
ly from our own confcioufnefs of effort, nothing is
more certain than that bodies exhibit at once the ap¬
pearances which we endeavour to exprefs by thefe words.
We bring the north poles of two magnets near each o-
ther, and they recede from each other 3 if this be pre¬
vented by fome obftacle, they prefs on this obftacle,
and feem to endeavour to feparate. If while they are
in this ftate, we eleClrify one of them, wre find that they
will now approach each other 3 and fo we have a diftinCt
proof that both tendencies are in^ aClual exertion by
varying their diftances, fo that one or other force may
prevail 3 or by placing a third body, which ftrall be
afteCted by one but not the other, &c. We do not
underftand, nor can we conceive, how either force, or
how gravity refides in a body. It muft be granted,
therefore, that this additional circumftance of iEpinus’s
hypothefis has nothing in it that is repugnant to the ob-
ferved phenomena of nature.
In order to limplify the algebraic expreflions which 322
we employ in confidering the actions of thefe bodies, wx
may remark, that, as in the natural ftate of the bodies
they do not affedt each other, we need only, in examin¬
ing the adtions of bodies not in their natural ftate, con¬
fider the action of the redundant fluid or the redundant
matter in them, that is, the fluid or matter which is un-
faturated: for we may confider an overcharged body as
one which contains a quantity of faturated fluid, and a
quantity of unfaturated fluid additional 3 and an under¬
charged \oodcj as one containing a quantity of faturated
matter, and a quantity of unfaturated matter in ad¬
dition.
Suppofe two bodies A and B overcharged, or con¬
taining each a quantity of unfaturated fluid, which we
ftiall call F' and f. Their mutual adtion on each other
will be F' X f'-\-tc,, and it is evident from what was faid
before that this is a repulfion. Hence we have the fol¬
lowing general propofition.
1. Tvoo overcharged bodies repel each other with the 323
force F'x/'-J-ss-
Now let thefe bodies be undercharged, or contain
each a quantity of unfaturated matter, M', m!. Their
mutual adtion will now be M'x^-J-z. This adtion is
alfo repulfive, and hence
2. Two undercharged bodies repel each other with the 324
force M' X "/ -{- 2;.
Again, let one of the bodies A be overcharged or con¬
tain the unfaturated fluid F;, and the other B under¬
charged, or contain the unfaturated matter m'. Their
mutual adtion will now be exprefled by the fymbol
F xm'fz, and will be attradtive 3 or
3. Izvo bodies which are, one overcharged, and the
other undercharged, attract each other with the force
F' X +2;.
Laftly, let one of the bodies be overcharged or un¬
dercharged, and the other in its natural ftate. We infer
from the above formulae, that they will neither attradl
nor repel each other, or that they will be neutral; for
here either F' or f, or M' or m', one of the factors w hich
made part of the above produdts, is w anting. This may
be inferred alfo, independently of the formula*, by coiy-
J B 2 fidering
$26
3*7
3i»
74* K L E C T
Theory °f fideiing that the redundant fluid or redundant matter in
Electricity. onc [s ag much repelled or attradled by the fluid
or matter in the other, as it is attracted or repelled by
the matter or fluid in this other. Hence.
4- If °f lwo bodies, one be in its natural Jlate, they
will neither attract nor repel each other.
I he truth of the three iirft propofitions will be evi¬
dent from the experiments related in the laid Part,
Chap. I. where we found that bodies which were elec¬
trified both pojitively or both negatively, repelled each
other, and that when one body was electrified pojitively
and the other negatively, they attra&ed each other. But
the laid propofition feems contrary to the phenomena •,
and it certainly contradidds a part of the Franklinian
doddrine, which maintains that there is an attraddion be¬
tween an electrified and a non-eleSirif ed body, we {hall
prefently, however, demonldrate the truth of the pro¬
pofition, but muft now proceed in our explanation of
iEpinus’s theory.
Suppofe the body EC, fig. py. to be overcharged in
the half AC, and undercharged in the half AB, and
let us now reprefent the redundant fluid in the part
AC by the fymbol f', and the redundant matter in
AB by in'; let the body D near BC be overcharged
with the redundant fluid F' j let % and <zl denote the
force of addion exerted on 13 at the difdances of this
body from the overcharged or undercharged parts of
BC. Now D is repelled by AC, with the force Y' f vd,
but it is attradded by AB with the force F' in' ; on
the whole, therefore, D will be attradded or repelled by
BC, according as Y' in' % is greater or lefs than Y' f ,
or (becaufe F is common to both) as m' %' is greater or
lefs thany' z. But this will depend on the proportion
that/7 bears to in', or z to td. Now, the former of
thefe is regulated by many external circumftances
which may tend to produce a greater or lefs redundancy
or deficiency of fluid ; and the latter depends on the
law of eleddric addion. Without inquiring at prefent
into this law, it is fufficient to recoiled! that the addion
decreafes with every increafe of diftance, and that the
attraddion and repulfion at the fame diftance are equal.
Both, therefore, vary according to the fame law, and
2: is always greater than td. _
But the fenfible addion of BC on D, and (as addion
and readdion are equal and contrary) of D on BC, may
vary with every new pofition of BC, and even in the
• fame pofition.
1. Let us fuppofe that BC contains on the whole its
natural quantity of fluid, but that part of it is taken
from AB, and crowded into AC. This, which is a very
common cafe in eleddricity, may be expreffed in our
fymbolic manner by making y^z/rc'. Now, in this cafe,
py •z is greater than F'm'd, as % is greater than <d.
A mutual repulfion will therefore take place between
BC and D, and this may be exprefled by F'y X
{z—z'').
2. If D were placed on the redundant fide of BC, it
is evident that the addion would be reverfed, and the
above fymbol will exprefs the attraction between BC
and D.
Again, if inftead of fuppofing D to be overcharged,
we make it undercharged, the adtions will again be
changed : in its prefent fituation it will be repelled ;
on the oppofite fide of BC it will be attradded.
331 3- No addion may be exerted between them ; for the
R I C I T Y.
Part IV.
329
330
redundancy and deficiency in BC may be inverfely pro- Theory of
portional to the forces, or we may have f' in': — z' : jg.Eledhicity.
Now, multiplying extreme and mean terms, we have ’',l ’’
fl 2;
y z—m' %', and again 111’——^. In this cafe the ac¬
tions counterbalance each other, and when D is at the
prefent diftance from the overcharged part AC, it is-
neither attradded nor repelled. 13, and that part of
BC that is contiguous to it, may both be overcharged,
and yet BC may exert no addion on 13, or may be neu¬
tral with refpedd to it.
Now fuppofe D on the oppofite fide of BC ; the ef- 334
r • • Z7 2;
fedds will be different ^ for as m'zzz——, and/// z' is now
z'
become in'z, andy 55 is changed intoy5$', the addion
on D will be expreffed by F' x   f z'^j —F' f
;— ; of courfe D will be attradded.
x —
Again, we may havey and in! fo proportioned as 333
that when X), which we fuppofe overcharged, is placed
at the undercharged end of BC, it fliall be neither at¬
tracted nor repelled, or that at this exadd diftance BC
fhall be neutral. In this cafe, m'~J-—. But if D
z
be on the oppofite fide of BC, it will be ftrongly re¬
pelled wfith the force F'y X (- ).
\ x J 334
Hence W’e fee that when the overcharged end of an Bodies neu-
eleddrified body becomes neutral with refpedd to anothertral at one
body that is alfo overcharged, the undercharged end thar^aioa
ftrongly attracts that body j and wLen the underchar- at the
ged end becomes neutral to the body, this is ftrongly other in-
repelled by the overcharged end, as wTe may deducecreaiec*-
from this reafoning the following general conclu-
fion.
When an eleBrifed body is neutral at one end, it is
rendered more aCiive at the other.
One circumftance merits particular attention. In the 335
above paragraphs, the neutrality of BC has been con¬
fined to a particular dildance of the body D, it being
• y
required that m' fhould ’1 ^et ^ placed near¬
er to BC and both z and d are increafed. Their in¬
creafe may be in the fame proportion 5 or one may in¬
creafe fafter than another : in the former cafe, the value
of —t, remains the fame, and the neutrality continues j
in the latter, if z increafes fafter than d, f z becomes
greater than m! d, and D will be repelled : on the
other hand, if d increafes fafter than z, D w-ill be at¬
tracted. Let D be carried farther from the overcharg¬
ed end of BC, and the effects wfill be reverfed.
We have been fuppofing that D is overcharged e;Lc! of
throughout, but let us take two bodies AB, and CD, unequal
fig. 98. AB being overcharged in u B, and underchar-
ged in // A 1 and CD being overcharged in v D, and^0?.*11
undercharged in v C. bodies-
In the firft place, let us have the overcharged end
of AB oppofite the undercharged end of CD as in the
figure. Let F and f be the fluid natural to each, F'
and f the redundant fluid in u B, and v D, and M'
and id the deficient fluid in u A and v C. Let Z and
Chap.
339
la
It is evident that the
I. E L E C T R
Theory of Z' denote the inteniity of aftion exerted by a particle
Electricity. in w B on a particle in v D and v C j and let ss and
' y in like manner exprefs the intenfity of aftion of a par¬
ticle in A on a particle in ^ D and in v C.
It will ealily appear from the former examples that
the aftion of CL) on AB will be
F m' Z — F/' Z' — M' nil %+M'/' 2s' . , . , .
1/
mula the attradlions are denoted by and the repul-
lions by —.
The attradlive or repullive power will prevail ac¬
cording as the fum of the firft and laft terms in the nu¬
merator of the above fradtion is greater or lefs than the
fum of the two middle terms. Again the value of
each term will vary with the quantity of redundant
fluid or of redundant matter, and with the intenfity of
the electric adtion. As it would lead us into too long
a difcuflion were we to notice the numerous varieties
of effedt, we lhall only ftate the moft fimple cafe, as
being the mofl: frequent and moft ufeful.
337 Let us fuppofe that the overcharged part of each
body is as much redundant in fluid as the undercharged
part is deficient •, in which cafe we have F=M' and f
z=.m. The adtion will now be expreffed by the formu-
F/' (Z—Z') — s-fs;'
Wf
external effedl produced on AB mull depend on the
law of action; if Z-f-ss' be greater than Z'-fs;, AB
will be attra&ed, but if Z'-f-z' be lefs than Z'-fz, ft
will be repelled.
33^ It will be a confiderable relief to the imagination to
exprefs thefe abftradt values by fome fenfible quantities,
fuch as lines, and this may conveniently be done in
the following manner. From a fixed point in a flraight
line, meafure off portions refpedtively equal to BC, BD,
AC and AD, between thofe points of the bodies A B,
CD, fig. 98. in which we fuppofe the forces of the re¬
dundant fluid and matter to be concentrated, and at the
extremities of thefe portions eredt ordinates proportion¬
al to thefe forces. Though the law of adtion be but
imperfedtly known, it will readily be feen of wdrat kind
the movements of the bodies will be. Thus in fig. icq.
from C in the line CZ, make C/>=BC : C y—BD :
C/’zrAC, and C/z=:ADy and eredt the ordinates P/>,
y, R r, and T t. If the adtion of eledtricity be like
other attradlive and repulfive forces with -which we
are acquainted, that is, decreafing with an increafe of
diftance, and more flowly as that diftance becomes
greater, the ordinates will be bounded by fuch a curve
as PQRTZ, that will have its convexity towards the
axis C sz.
In our conftrudlion, the pair of ordinates P/>, £) y
are evidently equidiftant with the pair R rT t; as are
P />, R r, with Q y, T /. It is alfo clear that the fum of
P/>andT t is greater than the fum of (£y and R r. Bifedt
C 2; in -y, and draw V v perpendicular to it, cutting
PT and (^R in x and ?/. Then * f is the half of P/>
-fT/, and y vis the half of (,) y-}-R r. Again, C)///
and T n being drawn parallel to C 2, it is evident that
P m is greater than R r, and in general, if any pair of
ordinates be brought nearer to C, their difference in-
creafes ; and if two pairs be brought nearer to C, the
difference of the nearer pair will increafe fafter than
that of the more remote.
34°- To apply what has been ftated.
I C I T Y. 749
1. When the overcharged end of AB is towards the Theory of
undercharged end of CD, AB is attradled, as P/> -f-T t Ehedtncit)..
is greater than t^y-j-R r.
2. The nearer the bodies are brought, the more the
attraction will increafe, as the difference between P m
and R r is thus made greater.
3. The greater the length of AB or CD, the difi*
tance BC being the fame, the more the attradlion will
increafe : for pr or: q t, (which reprefent the length of
AB) being increafed, R r is diminilhed more than
Tt.
But if the overcharged end of CD be oppofite to the
overcharged end of AB, their mutual adtion will be
reprefented by F’f P/,-+^^+R r~1
and AB will be repelled; the repulfion becoming
greater or lefs, as the attradlitms, by every change of
diflance.
Having thus examined at fome length the refults of
a redundancy or deficiency of fluid, fuppofing it to be
immoveable, we mult now proceed to confider the con-
fequences of its mobility. 341
Let D, fig. 97. contain redundant fluid w'hile BC isEfRdf °f _
fuppofed in its natural ftate, and let the fluid in D be ^,ie
fixed, but that in BC moveable. The redundant fluid
in D will exert its repulfive power, and will drive the
fluid of BC from the proximate end B towards the re¬
mote end C, fo that the fluid will be .rarefied in AB,
and conftipated in AC. Without examining here the
mutual aftions of the redundant fluid and matter, it is
clear that we have a cafe fimilar to that defcribed in
^309. and as f'~m' and % is greater than 2;', D will
be attradled by BC, with the force Y’ f x («—«')•
We may now folve the difficulty mentioned in N°
3 27. and perceive that the hypothefis agrees with the
fad! even in the cafe in which it appeared fo oppofite.
Had the fluid been immoveable, no attradlion would
indeed have taken place but as it is fuppofed move-
able, the redundant matter in the vicinity of D pre¬
vails, and a mutual attradlion enfues.
For the fake of greater fimplicity, we have fuppofed 343
the fluid in D immoveable, but let us fuppofe it move-
able. In that cafe, as foon as the uniform diftribu-
tion on BC is difturbed, and it becomes overcharged in
AC, and undercharged in AB, certain forces begin
to ad! on D, tending to difturb its uniformity. The
redundant matter towards B attradls the fluid in D,
more than the redundant fluid toward C, which is more
remote, repels it; %' being lefs than 2;. By this at¬
tradlion the fluid of D tends to be conftipated in the
proximate extremity, and thus again AB is more un¬
dercharged, and AC more overcharged than before.
Thus the mutual adlion between the bodies is ftill more
increafed. But it is ftill of the fame kind ; forhowever
fmall the redundancy in D may be, it can never be
made deficient in its remote extremity by the irregular
difpofition of the fluid in BC, unlefs BC contain more
or lefs than its natural quantity. By the change in the
difpofition of fluid in D, it is clear that the fimilar
change in BC muft be increafed ; the fluid will be ftill
more rarefied at B and condenfed at C, and this will
go on till all is in equilibria. There are feveral forces
combining to hold m equilibria a particle in BC. The
redundant fluid in D impels it towards C ; but the re¬
dundant fluid here again impels it towards B, while the
redundant
75o
Theory of
■Eleiflncirv.
343
344
Induced
electricity.'
345
Efteci of
ohftruc-
tions.
redundant matter at B attrads it the fame way •, and
thefe two forces of; EC mull he fuppofed to balaitce the
adlion of D.
We may here conclude that the denfity of the fluid
in BC increafes gradually from B to C ; at B it mull
be lefs, and at C greater than the natural denfity, and
there wiB confequently be fome point between B’ and C
\\ .iere it is of the natural denflty. ’I'his point may be
called a neutral point j though we do not mean to im¬
ply by this term that a particle fituated at this point
is neither attrafled nor repelled.
We have fuppofed the fluid in D redundant; but let
it be deficient. Then the attraftion of the redun¬
dant matter in D will change the difpofition of the
moveable fluid in BC, and will conftipate it in B, and
rarefy it in C. Again, the redundant fluid at B will
aft more Wrongly on the moveable fluid in D, and tend
to impel it towards the remote extremity j and D will
thus become undercharged in its proximate extremity,
and lefs undercharged at its remote end than if BC were
away. The unequal dillribution of fluid in BC will
thus be increafed •, but though both BC and D will be
farther from their natural Hate, the remote end of D
can never be overcharged.
It is clear, that when things are in the Hate which
we have defcribed, D and BC will attradl each other
with the fame force as when D was equally under¬
charged.
Let a body, A, (fig. ioi.) that is overcharged, be
placed near the extremities of two oblong parallel con-
dudlors, B and C, that are in their natural ftate. By
the aftion of A, the fluid in B and C will be repelled to¬
wards their remote ends N and 77, where it will be conden-
fed, while at their proximate ends, S and s, it will be
rarefied. Both B wall attract and be attradled by A.
Now the redundant fluid in NB repels the redundant
fluid in n C, and in like manner the redundant matter
in SB repels the redundant matter in a C ; the bodies
B and C therefore repel each other, and will feparate;
but they ought to approach each other, for SB attracts
77 C, and NB attracts a C 5 but the repelling parts be¬
ing nearer each other than the attradting parts, the
forces of the former will prevail. If the body A were
undercharged, it is clear that the fame JenJible appear¬
ances would take place, though the internal motions
of the bodies would be the reverfe of the former.
If another body in the fame date with A be placed
near the oppofite ends of B and C, their internal mo¬
tions will be diminilhed or prevented, and of courfe the
fenfible appearances fliould diminifh alfo.
If another conductor, as E, be placed near s, oppofite
to A, it will be aftedted in the fame manner with C,
and its proximate extremity f will repel j-; but if it be
placed at the remote end, or in the pofition of F, this
remote end will be attradled. As the body A, when
redundant or deficient, affedts every other body in its
vicinity, while thefe do not by themfelves afiedt each
other, A is called the eledtrified body, and the others
are faid to be eledtrified by it. The elediricity of thefe
bodies is called Induced EleBricity.
We have hitherto fuppofed the fluid moveable, ex¬
cept at firft in A 5 but let us fuppofe that there is fome
obftrudtion to its mobility, and let us examine what
will be the confequences. We may date the obitrudiion
E L ECTRICIT V.
Part IV.
as uniform, and as being fuch that fome fmall force is Theory of
required. to enable a particle of fluid to pafs between Ekdlricit}-.
two particles of matter. * —v—
When an overcharged body is placed near an imper-
fedt condudtor, it is clear that the fluid cannot be pro¬
pelled to the remote extremity of the condudtor in fo
great a quantity. We may conceive the diitribution
o. the fluid, by taking a conftant quantity from the in-
tenfity of the force of the overcharged body at every
point of the condudtor. This ftiows that the diitribu¬
tion will not be fo unequable between imperfedt, as be¬
tween perfedt condudtors, and hence that the attradtion
between the former will not be fo itrong as between
the latter. It wall alfo be much longer before an equi¬
librium can be brought about. This leads us to an im¬
portant confequence; viz. that the neutral point will
not be fo far from the other body when the fluid is of
its natural denfity, as it would be, were there no ob-
Itructions. The advance of this point along the imper-
fedl condudtor will alfo be very flow ; and it is clear,
that the final accumulation at the remote extremity of
an imperfedt condudtor -will be lefs than if the conduc¬
tor were perfedt, and the neutral point will be nearer
to the other extremity.
_ f he obftrudtion we are confidering will be attended 345
with another remarkable effedt. The conftipation of the
fluid at the commencement of the adtion will ahvays be
greateft at a place much nearer to the difturbing caufe
than the remote end of the condudtor, and beyond that
point it will diminifh. In the time that elaples during
the progrefs of this change, the condenfed fluid tends
to repel the fluid beyond it, and thus fome of this re¬
mote fluid may be difplaced, and a part of the imper¬
fedt condudtor made deficient, while there is a fmall
condenfation beyond it. By this again a rarefadtion
and condenfation may be produced in another part,
thus cauiing a very irregular diftribution of the fluid.
I he effedt of fuch a mode of adtion will be that there
may be feveral neutral points in an imperfedt conduc¬
tor, and feveral overcharged and undercharged por¬
tions, and hence its adtion on diltant bodies may be
extremely various. The formula^—^r ?_i_>
wtiere f g, h, 7’, exprefs the different portions in oppo¬
fite itates, and r, r', iJ\ r///, the repulfion at different
diftances, may be conveniently employed to denote the
adtion in fuch circumltances. Hence, if another body
be placed in the diredtion of the axis, it will be at-
tradted at one diitance, repelled at a greater, again at-
tradted at a ftill greater diitance, and fo alternately.
The obitrudtion may not be confiderable, and then
the adtion of the neighbouring overcharged body will
produce a deficiency in the proximate part of the con¬
dudtor, a redundancy farther on, then a deficiency,
and fo on. Prefently thefe will fhift, and fucceffively
difappear at the farther end, and the body will remain
with only one neutral point. A greater obitrudtion
will leave the body with more than one neutral point,
and the number of thefe will be in proportion to the
obitrudtion. 347
The removal of an overcharged body from the vici- j
nity of condudtors will have different refults accordingly ^Ity
as the condudtcrs are perfedt or imperfedt, that is, ac- cone pe r.
cording as there is pbftrudtion or not. In the former manent in
m per left
;o:.dudroi5.
ca.e,
/
Chip. I. ELECT
Theory of cafe, the electricity induced by the vicinity of the over-
Eledtricity charged body will be iaftantly deftroyed on the removal
^ ' of the body. But where there is an obftrudtion act¬
ing, though, on the removal of the body, the forces
that tend to reftore the equilibrium in the conductor
begin to act, and reitore it in part, they can never do
this completely j for when the force by which a par¬
ticle is propelled from an overcharged part to one un¬
dercharged is juft fufticient to balance the obftruftion,
it will remain in that ftate of diftribution at which it
had arrived. We may expert then, that imperfect
conductors will retain a part of their induced electri¬
city.
On the removal of the electrifying body, the elec¬
tric appearances induced by it in the conduftor will
difappear in a contrary order to that in which they
were produced, and they will be left in a ftate of un¬
equal diftribution, or with a degree of eleftric power,
proportioned to their imperfection as conductors.
We have now given an account of the principal confe-
quences of the theory of iEpinus, a theory which till of
late was little known in Britain, owing probably to
the very lame and imperfeCt account given of it by Dr
Prieftley in his popular work on eleCtricity. More juf-
tice has been done to this theory by Mr Cavendilh, who
before he faw M. ^Epinus’s work had framed an hypo-
thefts of his own upon very fimilar principles. Mr Ca-
vendiih’s paper, in which he has treated this fubjeCt
in a very able and learned manner, appeared in the 6ift
vol. of the Phil. Tranf.
To this paper we fhall be much indebted prefently ;
but in the mean time we fhall only extraCl from it the
-4S hypothefts, which is as follows.
Cavendifii’s There is a fubftance which we call the electric fluid,
aypothefis. the particles of which repel each other, and attraCl the
particles of ail other matter, with a force inverfely as
tome lefs power of the diftance than the cube } the par¬
ticles of all ether matter alfo repel each other, and at-
tract thofe of the eleCtric fluid, with a force varying
according to the fame power of the diftances. Or,, to
exprefs it more concifely, if you look upon the eleClric
fluid as a matter of a contrary kind to other matter,
the particles of all matter, both thofe of the eledlric
fluid and of other matter, repel particles of the fame
kind, and attraCl thofe of a contrary kind, with a
force inverfely as fome lefs power of the diftance than
the cube.
For the future, he would be underftood never to com¬
prehend the eleftric fluid under the word matter, but
only fome other fort of matter.
It is indifferent whether we fuppofe all forts of mat¬
ter to be endued in an equal degree with the foregoing
attraflion and repulfion, or whether you fuppofe fome
forts to be endued with it in a greater degree than
others •, but it is likely that the elesftric fluid is endued
with this property in a much greater degree than other
matter ; for in all probability, the weight of the elec¬
tric fluid in any body bears but a very fmall proportion
to the weight of the matter ; but yet the force with
which the ele&ic fluid therein attracts any particle of
matter muft be equal to the force which the matter
therein repels that particle ; otherways the body would
appear eledlrical, as will be fhown hereafter.
To explain this hypothefis more fully, fuppofe that
one grain of electric fluid attracts a particle of matter
R I C 1 T Y. 751
at a given diftance with as much force as « grains of Theory -,f
any matter, lead for inftance, repel it: then will one Electricity.
grain of electric fluid repel a particle of eledtric fluid '' "v '
with as much force as n grains of lead attradt it j and
one grain of electric fluid will repel one grain of electric
fluid with as much force as n grains of lead repel n
grains of lead.
All bodies, in their natural ftate with regard to elec¬
tricity, contain fuch a quantity of eledtric fluid inter-
fperfed between their particles, that the attraction of
the electric fluid in any fmall part of the body in a gi¬
ven particle of matter, lhall be equal to the repullion of
the matter in the fame fmall part, in the fame par¬
ticle,
A body in this ftate is faid to be faturated with elec¬
tric fluid ; if the body contains more than this quantity
of eledtric fluid, he calls it overcharged ; if lefs, he calls
it undercharged.
Sect. III. Of the Theory of two Fluids.
This theory originated, as we have faid, in M. du 349
Faye’s difeovery of the different ele&ricities produced
by rubbing glafs and fealing-wax.
Let us fuppofe that there are two eleftric fluids,
which have a ftrong affinity for each other, while, at
the lame time, the particles of each are ftrongiy repul-
five of each other. Let us fuppofe thefe two fluids in
fome meafure equally attraded by all bodies, and ex-
ifting in intimate union in their pores 5 and while they
continue in this manner to exhibit no mark of their ex-
iftence, let us fuppofe that the friftion of an ele£tri<?
produces a feparation of thefe two fluids, caufing (in
the ufual method of eleftrifying) the vitreous eledfri-
city of the rubber to be conveyed to the conduftor,
and the reftneus eleftricity of the conduftor to be con¬
veyed to the rubber. The rubber wall then have a
double ffiare of the reftnous eleftricity, and the conduc¬
tor a double ffiare of the vitreous ; fo that, upon this
hypothefis, no fubftance whatever can have a greater
or lefs quantity of eleftric fluid at different times 5 the
quality of it only can be changed.
The two eleftric fluids being thus feparated, wall
begin to Ihow their refpeftive powders, and their eager-
nefs to ruffi into re-union with each other. With
whichever of thefe fluids a number of bodies are
charged, they wall repel one another: they wall be at-
trafted by all bodies, which have a lefs ftiare of that
particular fluid with which they are loaded j but will
be much more ftrongiy attrafted by bodies which are
wholly deftitute of it, and loaded with the other. In
this cafe, they wall ruflr together with great violence.
On this theory, the eleftric fpark confifts of both
the fluids rmffiing in contrary direftions, and making a
double current. When, for inftance, the finger is pre-
fented to a conduftor loaded with vitreous eleftricity, it
difeharges it of part of the vitreous, and returns fo
much of the refinous, which is fupplied to the body
from the earth. Thus both the bodies are uneleftrified,
the balance of the two powers being reftored.
When the Leyden phial is prefented to be charged,
and confequently the coating of One of its fides is con-
nefted with the rubber, and that of the other with the'
conduftor; the vitreous eleftricity of that fide which is
connefted with the conduftor is trani'mitted to that
which
752
Theory of which is conne&ed with the rubber, which returns an
*'':eC ';clty' equal quantity of its refinous eleftricity ; fo that all the
vitreous eleftricity is conveyed to one of the Tides, and
all the relinous to the other. Thefe two fluids heirsy
thus feparated, attraft each other very ftrongly through
the thin fubftance of the intervening glals, and ruth
together with great violence, whenever an opportunity
is prefented, by means of proper conductors. Some¬
times they will force a paflage through the fubftance of
the glafs itfelf $ and in the mean time, their mutual at¬
traction is ftronger than any force that can be applied
to take away either of the fluids feparately.
Dr Prieftley gives the following view of the compa¬
rative merits of this theory and that of Dr Franklin.
“ In the firft place, (fays he)* the fuppofition itfelf
of two fluids, is not quite fo eafy as that of one, though
it is far from being difagreeable to the analogy of na¬
ture, which abounds with affinities, and in which we
fee innumerable inftances of fubftances formed, as it
were, to unite and counteract one another.
The two fluids being ftippofed, the double current
from the rubber to the conduCtor, and from the conductor
to the rubber, is an eafy and neceffary confequence.
For if, on the common fuppolition, the aCtion of the
rubber puts a fmgle fluid into motion in one direction,
we might expeCt, that if there were two fluids, which
counteracted each other, they would, by the fame
operation, be made to move in contrary directions.
And a perfon that has been ufed to conceive that a
fingle fluid may be made to move either way, viz. from
the rubber to the conduCtor, or from the conduCtor to
the rubber at pleafure, according as a rough or a fmooth
globe is ufed, can have much lefs objection to this part
of the hypothefis.
Admitting theri this different aCtion of the rubber
and the eleCtric upon the twTo different fluids, the man¬
ner of conveying eleCtric atmofpheres, or powers, to
bodies is the fame on this as on any other theory j and
it is apprehended that the phenomena of negative elec¬
tricity are more eafily conceived by the help of a real
fluid, than by no fluid at all. Indeed Dr Franklin
himfelf ingenuoufly acknowledges, that he was a long
time puzzled to account for bodies that were negative¬
ly eleCtrified, repelling one another $ whereas M. du
Faye, who obferved the fame faCt, had no difficulty
about it, fuppofing that he had difeovered another
eleCtricity, fimilar, with refpeCt to the properties of
elafticity and repulfion, to the former.
By this double aCtion of the rubber, the method of
charging a plate of glafs is exceeding eafy to conceive.
Upon this hypothefis, all the vitreous eleCtricity quits
its union with the refinous on the fide communicating
with the conduCtor, and is brought over to the fide
communicating with the rubber •, which, by the fame
operation had been made to part with its refinous elec¬
tricity in return.
All the vitreous eleCtricity being thus brought to
one fide of the plate of glafs, and all the refinous to the
other, the phenomena of the plate while ftanding
charged, or difeharged, are perhaps more free from all
difficulty than upon any other hypothefis. When one
of the fides of the glafs is conceived to be loaded with
one kind of eleCtricity, and the other with the other
kind ; the ftrong affinity between them, whereby they
-attraCt each other with a force proportioned to their
3
Part IV»
nearnefs, immediately fupplies a fatisfaCtory reafon, why Theory of
fo little of either of the fluids can be drawn from one £ledtricity.
of the fides without communicating as much to the v
ether. Upon this fuppofition, that confequence is per¬
haps more obvious, than upon the fuppofition of one
half of the glafs being crowded wnth the eleCtric mat¬
ter, and the other halt exhauifed. In the former cafe,
every attempt to withdraw the fluid from one of the
fides, is oppofed by the more powerful attraction of the
other fluid on the oppofite fide. On the other hypothe¬
fis, it is only oppoled by the attraction of the empty
pores of the glafs.
Laftly, The explofion upon the difeharge of the glafs
has as much the appearance of two fluids ruffiing into
union, in two oppofite directions, as of one fluid pro¬
ceeding only in one direction. The fame may be laid
of the appearance of every eleCtric fpark, in which,
upon this hypothefis, there is always fuppoied to be two
currents, one from the eleCtric, or the eleCtrified body,
and the other to it.
I do not fay, continues Dr Prieftley, that the bur
which is ufually feen on both fides of a quire of paper
pierced by an eleCtric explofion, and the current of air
flowfing from the points of all bodies eleCtrified nega¬
tively as well as pofitively, are material objections to
the doCtrine of a fingle fluid. But upon the fuppofi¬
tion of two fluids and two currents, the difficulty for
accounting for thefe faCts would hardly have occurred.
It is almoft needlefs to obferve, that the influence of
points is attended with exaCtly the fame difficulty
upon this theory, as upon the other. It is equally
eafy, or equally difficult, to fuppofe one fluid to en¬
ter and go out at the point of an eleCtrified conduCtor
at different times, as to fuppofe, that, of two fluids, one
goes out, and the other goes in, at the fame time.
That bodies immerged in eleCtric atmofpheres muft
acquire the contrary eleCtricity, is quite as eafy to fup¬
pofe upon this, as upon any other hypothefis. For, in
this cafe, fuppofe the eleCtrified body to be poffeffed of
the vitreous eleCtricity, all the vitreous eleCtricity of
the body which is brought near it will be driven back-
■wards to the more diftant parts, and all the refinous
eleCtricity will be drawm forwards. And, wffien the
attraction between the two electricities in thefe differ¬
ent bodies is fo great as to overcome the oppofition to
their union occafioned by the attraction of the bodies
that contained them, the form of their furfaces, and
the refiflance of the interpofing medium, they will ruffi
together; an eleCtric fpark will be vifible between them j
and the eleCtricity of both will appear to be difeharged 5,
the prevailing eleCtricity of each being faturated with
an equal quantity of the oppofite kind, from the other
body.
This hypothefis will likewife eafily account for the
difficulty of charging a very thick plate of glafs, and
the impoffibility of charging it beyond a certain thick-
nefs 5 for thefe fluids, at a greater diftance, will attraCt
one another lefs forcibly, and at a certain ftill greater
diftance will not attraCt at all.”
Dr Prieftley makes the following anfwer to the
principal objection that may be urged againft this
theory.
“ If it be afked (fays he), why the twTo fluids meet¬
ing on the furface of the globe, or in the eleCtric ex¬
plofion, do not unite by means of their ftrong affinity,
and
ELECTRICITY.
Chap.
I. ELECT
Theory of and make no further progiefsj it maybe anfvvered,
Ele<£>ricity.that the attraction between all other bodies and the
v particles of both thefe fluids, may be fuppofed to be
at leaft as ftrong as the affinity between the fluids
themi'elves j fo that the moment any body is difpolTeffed
of one, it may recruit itfelf to its ufual point of fatu-
ration, from the other.
Beiides, in whatever manner it be that one of the
eleClric fluids is diflodged from any body (lince upon
every theory the two eleftricities are produced at the
fame time) the oppofite eleftricity will, by the fame
adtion, be diflodged from the other fubftance. And
whatever it be that diflodges the fluid from any fub-
flance, it will be fufficient to prevent its return ; con-
fequently, fuppofing both the fubftances necefl'arily to
have a certain proportion of eleClric matter, each may
be immediately fupplied from that which was diflodged
from the other.
The rubber, therefore, at the time of excitation,
gives its vitreous eledricity to that part of the fmooth
glafs againit which it has been preffed, and takes an
equal quantity of the refinous in return. The glafs be¬
ing a non-condudor, does not allow this additional quan¬
tity of eleClricity to enter its fubftance. It is there¬
fore diflufed upon the furface, and, in the revolution of
the globe is carried to the prime conductor. There it
repels the vitreous, and violently attracts the refinous
eleCtricity j and (the points of the conductor favouring
the mutual tranfition), the vitreous, which abounds up¬
on the globe, pafles to the conductor ; and the refinous,
which abounds upon the neareft parts of the conductor,
ruffies upon the globe. There it mixes with, and fatu-
rates wffiat remained of the vitreous eleCtricity on the
part on which it flows, and thereby reduces it to the
fame ftate in which it was before it wTas excited. Every
part of the furface of the globe performs the fame of¬
fice, firft exchanging electricities with the rubber and
then with the conductor.
The folution of this difficulty will alfo folve that of
the eleCtric explofion, in which there is a collifion, as it
were, of the two fluids, wffiile yet they completely pafs
one another. For ftill each furface of the glafs may be
fuppofed to require its certain portion of eleCtric mat¬
ter, and therefore cannot part with one fort without re¬
ceiving an equal quantity of the other. It muft be con-
lidered alfo, that the air through which the fluids pafs,
has already its natural quantity of eleCtricity, fo that
being fully faturated, it can contain no more, and that
the two fluids only ruffi to the places from which they
had been forcibly diflodged, and wffiere the greater
body of the oppofite fluid waits to embrace them.”
Although, in our explanation of eleCtrical phenome¬
na, W’e ffiall adopt the theory of Aipinus and Caven-
diffi, it is proper to obferve that this theory does not
univerfally prevail among the eleClricians of the pre-
fent day. The hypothefis of Du Fay, or the theory of
twTo fluids, is ftill maintained by feveral, efpecially on
the continent. This theory has lately found two ftre-
nuous advocates in France, M. M. Hauy and Tremery.
Their principal objeftion to the theory of /Epinus
feems to be founded on that part of his hypothefis with
which Afpinus himfelf wxas not perfectly fatisfied, but
w’hich (in N° 32I0 we have attempted to defend, viz.
his introduction of a repullive force among the particles
of matter in a body.
VOL. VII. Part II.
351 ,
Defence of
the theory
of two
f]ait's by
M. Tre-
snery.
R I C I T Y. 753
“ In faCt, (fay they), the fuppofition of a Angle fluid Theory of
of which the particles mutually repel each other, and are
attracted by the particles of matter in all known bodies, A
gives rife to many diftinCt forces, which cannot be in
equilibrio, and which, by their mode of aCting, are
fuch, that two bodies wffiich are in their natural ftate,.
and which are not attracted by any other force belides
that of eleCtricity, muft tend towards each other.
“ The fuppofition of a repulfive force among the par¬
ticles of matter in folid bodies becomes unneceflary if
wre conceive the eleCtric fluid as compofed of two
fluids, of which one poffefles the property whichALpinus
attributes to the particles of matter in the body. It is
much better to admit a repulfion at a diftance among-
the particles of two peculiar fluids, which, like all
others, repel each other, even in contaCt, than to con¬
ceive fuch a repulfion to exift among the particles of
bodies that are in their nature folid. Thofe philofo-
phers who endeavour to explain all the phenomena on
the principle of a Angle fluid, believed themfelves that
its particles repelled each other at a diftance, as from
one furface of the Leyden phial to the other ; and as
wffiat we call aElion at a difiance, is properly no more
than a fad on which we ground a'theory, without in¬
quiring what is the caufe wffiich furniffies the point of
difference, it is fufficient that the manner in which we
conceive this fact enables us to adapt it to our theory.
“ Atpinus, who does not conceal his reludtance to ad¬
mit that fuch a force as that which we have mentioned
can take place, would doubtlefs, (fay thefe gentlemen),
have adopted the hypothefis of two fluids, if in his time
the nature of the electrical phenomena had been bet¬
ter underftood. But, at that period, the means of ob-
fervation not being fo perfeCt, experiments had not been
made with that precifion which characterize thofe wffiich
we owe to M. Coulomb, and which have formed the
foundation of thofe important difeoveries, by means of
which this celebrated philofopher, far exceeding the
point at wffiich Atpinus refted, has carried the fcience
to a high degree of perfection, in that beautiful feries of
memoirs, in which w'e muft admire the addrefs with
wffiich he has availed himfelf both of experiment and
calculation.
“ Almoft all the phenomena of eleCtricity, then, feem
to depend on the aCtion of two peculiar fluids, which
aCt in fuch a manner, that the particles of each mutual¬
ly repel each other at a dijlance, with a force wffiich is
inverfely as thefquare of this difance, and attraCt the
particles of the other fluid with the fame force.
“ It is of confequence not to confound thefe two fluids
with the two currents, the one of influent and the other
of affluent matter, by wffiich Nollet attempted to explain
the phenomena. Thefe two currents belong to the
fame matter, and proceed, one from the conduCtor to~
wards furrounding bodies, the other from thefe towards
the conductor.
“We ihall now endeavour to apply the hypothefis
of twTo fluids to the explanation of fame phenomena
wffiich do not appear to agree with it, and which, by
the manner in which wre are accuftomed to view them,
feem to indicate that vitreous and reflnous eleCtricity
are only modifications of the fame fluid.
“ The experiments which feem to militate againft oujr
theory are very few7, and may be reduced to the fcl-
lowlng.
? C
Exper.
754 E L E C T R
/ heory of “ Kxper. I.—If upon a cake of rolin we trace various
Electricity. (}e£gns wit}j t}-,e p0jnt 0f a condu£ling fubftance, which
is at one time electrified pojttively, or by vitreous elec-
Experi- tricity, and at another negatively, or by rejinous elec-
ments that tricity ; and if on this furface, thus electrified, we let
HtateT mi ^a^ a Powder (g) properly difpofed ^ the defigns thus
RatnftVhis ren<^ere^ v^ible will prefent characters peculiar to each
theory. fpecies of eleitricity •, thus (hewing, according to the
followers of Franklin and TEpinus, a fuperabundance of
^ledtric fluid on one fide and a deficiency on the other.
“ Exper. 2. When a conducting body terminating in
a point, is electrified pojitively or by vitreous eleCtricity,
we perceive at the point a luminous brujh. And if, all
other things being equal, we fubfiitute negative or re¬
jinous electricity, the point is illuminated with a Jiar or
luminous point.
“ According to the theory of pofitive and negative
eleCtricity, the brujh indicates the tranfmiflion of eleCtric
fluidyrewz the body which is eleCtrified pofitively, and the
Jiar its entrance into the body which is negatively elec¬
trified.
“ Exper. 3.—When an eleCtric explofion takes place,
all the eleCtric fluid appears conftantly to pals from the
body eleCtrified pof lively to that which is eleCtrified
negatively.
Here they cite the method of proving this, by piercing
a card placed between the conducting balls of the uni-
verj'al difeharger. (Vid. N° 196. Exp. 2.)
Explained Thefe experiments, to which the theory of pofitive
by M. Tre- and negative electricity is happily applied, feem at firit
Ipery- fight inexplicable, according to the hypothefis of two
fluids. In faCt, the particles of thefe tw7o fluids being
fubjeCt to the fame laws, it feems,
1. That the defigns traced on a cake of rofin, or o-
ther ideo-eleElric fubftance, with the point of a conduc¬
tor, eleCtrified at one time pofitively and at another ne¬
gatively, fliould on the whole be fimilar.
2. That the luminous appearance obferved at the
fummit of a pointed conductor, ought always to be the
fame, whatever be the eleSirwalJlate of the body.
3. That when an eleCtric difeharge has taken place,
the vitreous and refinous eleCtricities, which mutually at¬
tract each other, ought to form a luminous train on each
furface of the card, and the card ought to be perforated
in a point equally diftant from the two extremities of
^ the balls of the difeharger.
M. Tie- The following is the manner in which M. Tremery
mery’s ex- undertakes to explain thefe appearances.
^ilanation. “ The matter, (fays he), to the aCtion of which wTe
attribute the ejeftrical phenomena, being confidered as
compounded of two peculiar fluids, wTe may conclude
that all bodies, confidered in the relation which they
bear to thefe fluids, do not pofl'efs the fame properties j
it is poffible that vitreous and reftious eleClricity may be
of fuch a nature, that, on the one hand, certain bodies,
whether eleftrics or conduftors, may have with refpeCl
to them difterent conducting powers \ and on the other
hand, that the coercive power (h) of ideo-eletlrics may
I c r T Y. Part IV.
vary according as they are oppofed to the motion of Theory of
particles proper to vitreous eleCtricity, pr to the motion EJedtricity.
of particles proper to ref nous eleftricity.
“ If, for inftance, the air of the atmofphere, in which
eleCtrical phenomena ufually take place, has an incom¬
parably greater coercive power with refpeCt to the re¬
finous eleCtricity than it has to the vitreous, it would be
very eafy to explain the experiments that wre have quoted.
In this cafe, the refinous eleCtricity, becaufe of the al-
moft infinite refiftance that the air would oppofe to the
motion of its particles, might be regarded as inherent
in the furface of the bodies ; whence it follows, that
the fame circumftances would take place, as if the body
eleCtrified rejtnoufy had the property of exercifing by
itfelf an attraction for the vitreous or poftive eleCtri-
city j a property which bodies in the negative flate
are fuppofed to have, according to the theory of
Franklin.
“ If nowr, the coercive power that we have fuppofed
the air to Iirvc with refpeCt to the refinous eleCtricity,
could diminifti fo as to become equal to that wdiich it has
with refpeCt to the vitreous, it would happen, that the
figns which induce us to regard the vitreous eleCtricity
as pofitive, and the refinous as negative, would difap-
pear, fo that all the phenomena would leem to depend
equally on the aCtion of the two fluids that would be
fubjeCt to the fame law. In this new' circumftance, we
ftiould obferve a luminous pencil at the fiummit of a
pointed conductor eleCtrified refnoufy or negatively,
and when an eleCtric dilcharge took place, the vitreous
and refinous eleCtricities would appear to approach each
other.
“ If, under thefe circumftances, the coercive power of
the air with refpeCt to the vitreous eleCtricity, fliould in-
creafe, fo as in its turn to become incomparably greater
than what it had with refpeCt to the refinous electricity,
it is evident, that the eleCtric matter, acting in the midft
of fuch a fubftance, would produce phenomena exaCtly
fimilar to thofe with which we are acquainted ; but, in
this cafe, the vitreous or pofitive eleCtricity wuuld per¬
form the office of the refinous or negative, and vice
verfa, and they would mutually exchange figns. A
luminous pencil would appear at a point eleCtrified ne¬
gatively or refinoufly, and a luminous ftar at a pofi¬
tive or vitreoufly eleCtrified point; and when two
conducting bodies, eleCtrified differently, were placed
at a convenient diltance, all the eleCtric matter would
appear to move from the negative body towards the
pofitive * Jaurn. dt
Pbyfique,
Chap. II. A theoretical Explanation of the Phenomena voi-ilv*
of Electricity.
Sect. I. Of the Nature and Difribution of the EleBric
Fluid.
355
Before wTe enter on a theoretical explanation of the Nature of
phenomena of eleCtricity, it will not be improper to in- the eledtrk
quire ffhd-
(g) This powder ftiould be compefed of two fubftances, which, by their mutual friCtion againft each other, are
capable of receiving oppofite eleCtricities.
(//) By coercive power our author underftands that which ideo-eleCtrics or conductors oppofe to the motion of the
particles that are proper to each of the ttvo fluids, that, according to this hypothefis, are fuppofed to form by their
union the elettric fluid.
Chap. II.
E L E C T R
Theory of quire fomewliat more at large into the nature of that
Electricity. fubtile agent which we have diftinguifhed by the
’ yr“ ' name of the eleftric fluid, and to notice fome of the
more plaulible opinions that have been hazarded on the
fubjeft.
One of the firfl: queftions that naturally arifes from
the very name of fluid is, What proofs have we of the
materiality of this power ?
Befides the properties of attra£tion and repulfion,
which are properties of matter, we have many other evi¬
dences that are very perfuafive, as being more diftindtly
r the obje£hs of our fenfes.
,proof, 0f its I. The fpark that appears when the elecfric power
SB&teriality. pafles fuddenly through the air ot any other relifting
medium, and the fnap, by which it is accompanied, are
ftrong evidences in favour of the materiality of the
power, by which they are produced. The noife of the
Ipark is occafloned by the fudden impreflion made on
the air, or fome other elaitic fluid, through which the
fpark pafies. When the air is confined in clofe veffels,
as in a tube above water, no very durable effeft is in¬
deed produced on the water in the tube. But this is
owing to the rapidity with which the expanlion ai\d fub-
fequent condenfation take place. Again, it is objected,
that it is impoflible to communicate motion to a very
delicate lever, nicely balanced, by throwing on it any
quantity of eleddricity. 'Some pretend to have done
this 5 but, however, the impoflibility of doing it is no
argument again it the materiality of the eleddric fluid j
and we might iuft as well fay, that a mulket ball is not
material, becaufe it may be fired through a paper or thin
board delicately fufpended, without imparting to them
'any part of its motion.
2. The light and heat accompanying the fpark, are
proofs of the materiality of the eleddric power. Thefe
are chemical phenomena j and whether we confider them
ns eflfe&s of the fluid as a Ample, or as refulting from its
decompofition, we conceive that they prove the materi¬
ality of the eleddric power, as completely as the materi¬
ality of caloric and light have been proved.
We are aware that this reafoning will not fatisfy
thofe philofophers who deny the materiality of caloric
and light j we know that much ilrefs is laid on the ex¬
periments of Count Rumford, as completely fubverfive
of the materiality of heat, experiments that could even
dagger the opinion of a Robifon. Without defiring in
the leafl: to detradd from the merit of that ingenious and
able experimentalift, for whom wre entertain a very high
elleem, we muft confefs, that wTe do not confider his ex¬
periments as warranting the conclufions that have been
drawn from them, and we are Hill difpofed to think the
materiality of caloric and light as fully proved as can be
expedded, with refpeft to matter that is not abfolutely
tangible.
’Electricity From the fimilarity of the chemical effects of the
fuppofed to electric fluid with thofe of elementary fire or caloric,
be the fame jj. was long ago (as we have {hewn in the beginning of
part^ fUpp0fec^ that they were the fame, and this
is ftill the opinion of fome electricians. We cannot here
pretend to enter on a full difcuffion of this queftion, but
we lhall briefly date the arguments in favour of the
identity of caloric, and the objeditions that we have to
make to them.
Electricity is the fame with caloric (fay the advocates
for their identity) becaufe,
with calo
ric.
I C I T Y. 75
1. Both produce the fame chemical effects, expanfion, Theory ot
fluidity, inflammation, oxidation, &c. _ ~,'Jc -
2. Thofe bodies that are the beft conductors of caloric,
as the metals, are alfo the belt conductors of elec¬
tricity •, and glafs, which is a very bad conduCtor of
caloric, is one of the molt perfect non-conduddors oi
electricity^ 35S
To the firfl: argument for their identity, we {hall re- Arguments
ply in the wmrds of M. Berthollet, who once conlidered^gainft this
them as the fame, but from experiments wras fatisfied that UPP°ltIon*
their effeCts were different.
“ A wire of platina was fubmitted to {hocks which were
nearly Itrong enough to effeCt its combuftion j and to be
fatisfied of this, a Ihock was excited, by which a great
part of the wire was melted and difperfed j afterwards
the ihocks employed were a little weaker, and im¬
mediately after each, the wrire was touched to judge of
the temperature it had acquired : a. heat was felt, wdiich
was diflipated in a few minutes, and wdiich, at the ut-
moft, was eilimated to refemble that of the boiling
point of water. If eledricity liquefied metals, and
brought them into combuftion by the heat it excites, the
platina wire muft after a ihock, which differed but little
from that which would have produced its difperlion and
its combuftion, have approached the degree of tempera¬
ture which odcafions its liquefaction : Now this degree*
which is the moft elevated that can be obtained, would,
according to the valuation, more or lefs accurate, of
Wedgwood, be 322770 of Fahrenheit.
“ When the Ihock is fufficiently ftrong to deftroy the
aggregation of the platina wire, it begins by detaching
molecul* from its furface, which exhale like fmoke } if
it is ftrong enough to produce combuftion, the remains
of the wire appear to be torn into filaments.
“ A thermofeope blackened with ink, and placed in the
fleam of a ftrong eledne {park, only experienced a dila¬
tation which was nearly equal to one degree of Reau¬
mur’s thermometer, and this flight effeft might depend
on the oxidation of the iron of the ink j placed befide
the current, it did not Ihow any dilatation, although the
air was necefiarily affected by the electric action : it was
the fame when it was placed in contact with a metallic
conductor, which received a ftream lefs powerful than in
the preceding experiments.
“ A cylinder of glafs filled with air, with an exciter at
each of its extremities, to one of which was fixed a tube
communicating with another cylinder filled with water,
produced an impulfe at each fliock, which railed the wa¬
ter more than a diameter above its level, but its effect
wras inftantaneous.
“ Thefe experiments feem to me to prove that electri¬
city does not a£t on fubftances, and on their combina¬
tions, by an elevation of temperature, but by a dilata¬
tion which feparates the moleculae of bodies. The flight
heat obferved in the platina wire, is only the effedt of
the compreflion produced by the moleculae which firrt
experience the eledtric adtion, or which experience it
in a greater degree 5 it muft, therefore, be compared
to that excited by percuflion or compreflion.
“ If the dilatation wTas the effedt of heat, that ex¬
perienced by a gas, in the experiment related above,
would not have been inftantaneous; it would only have
experienced a progreflive diminution by cooling, as w hen
its expanfion is owing to heat.
“ In the experiment by which ammoniacal gas is de-
5 C 2 compofed,
to
75<S ELECT
Theory °r compofed, the gas undoubtedly receives the electric ac-
, e^licuy tion, and neverthelefs it is not heated 5 and as foon as
the decompofition is finilhed, its volume remains un¬
changed, becaufe the eledlric aclion which is employed
in this experiment, is not fufficiently energetic to caufe
a perceptible dilatation. No fenfible dilatation is pro¬
duced by a gas in a fhock which is not very ftrong, be¬
came the impulfe not being gradual like the expanlion
arifing from caloric, and being excited inftantaneoufly,
the reliftance of the liquid becomes too great, and
cannot be overcome unlefs the dilatation has great
energy.
“ An experiment of Dieman and his learned affociates
confirms this explanation : they caufed a Ihock to pafs
through lead placed in a veffel filled with azotic gas,
which could not oxidate it j it was reduced into powder
retaining all its metallic properties: If it had ex¬
perienced a liquefaction fimilar to the action of heat,
it would have cooled gradually, and would have
congealed into one, or at lead into feveral maffes.
“ When a metal is fubmitted to the eleCtric aftion, the
effeCts produced immediately by the eleCtricity mult be
diltinguilhed from thofe which are owing to its oxida¬
tion : the fir It are limited to the diminution or deltruc-
tion of the effeCts of the force of cohefion, to removing
and difperfing the moleculae (if by this a little heat is
difengaged, it is only owing to the compreffion fultain-
ed by fome of the parts) ; but thofe which are occalion-
ed by the oxidation, produce a high degree of heat, and
then the eflfeCls alfume all the appearances of an ordi¬
nary combultion: hence it arifes, that the mod oxidable
metals are thofe which become red with the greatell fa¬
cility, and which mud diew the properties of a metal li¬
quefied by heat.
“ Electricity favours this oxidation in as much as it
diminilhes the force of cohefion ; it is thus that an alkali
renders the aClion of fulphur on oxygen much more
powerful, by dedroying the force of cohefion oppofed to
it, and that a metal diflblved in an amalgam, is oxidated
much more eafily than when it is in a folid date. It is
only by dedroying the effeCIs of the force of cohefion
that heat itfelf produces the oxidation of metals j but
the expanfive aClion of eleCtricity will have a great ad¬
vantage over that of caloric, bccaufe its aCtion is con¬
fined to the folid which it encounters in its courfe, fo
that the gas itfelf will not experience a dilatation in op-
pofition to the condenfation which accompanies the
combination : To this circumdance may be applied
what is obferved in the aCtion of hydrogen gas, which
is capable of completely reducing an oxide of iron placed
in the focus of a burning glafs, although water, whofe
two elements receive the heat equally, is decompofed by
- *Nhlolfon s this metal*.”
voTviii8™’ T° the fecond argument we lhall anfwer, that though
in the indance of metals it is correCI, in fo far as that
thefe bodies are the bed conduftors, both of caloric and
eleCtricity, there are however, bodies that conduCt calo¬
ric very well, but either do not conduEl eleCtricity, or
do it very imperfeCtly.
Even in the cafe of metallic bodies, fo far as can be
inferred from the imperfeCt experiments that have been
made on their comparative conducting power, it diould
appear that the order of their conducting power, with
refpeCt to caloric, is not the fame as that with refpeCt to
eleCtricity.
R 1 C I T Y. Partly.
Farther, caloric takes fome time to pafs through the Theory 0f
bed conductors, while the eleCtric fluid pervades the E*e<^ricity.
longed with inconceivable velocity. 1 v__,
Again, if eleCtricity were the fame with caloric, they
fliould mutually produce the fame effeCts, and diould
exid fimultaneoufly. But this is by no means the cafe j
a body may be drongly gleCtrified wdthout being fenfi-
bly increafed in temperature, and fo far is heat from
producing eleCtricity (except in a few indances), that
where the former is preient in any confiderable degree,
the latter is dedroyed.
Ladly, the mode in wdiich eleCtricity and caloric pafs
along conciuCtors is, w7e think different. Caloric teems
undoubtedly to penetrate their fubjiance, wdrile eleCtrici¬
ty appears not to extend beyond the furface, except it
meet wdth fome refidance. The following experiment
is ufually adduced to prove that eleCtricity pervades the
fubitance of conductors.
Take a wire of any kind of metal, and cover part,™55?
of it with fome eleCtric fubdance, as rofin, fealing- the eleftrim
wax, &.c. then difcharge a jar through it, and it fluid per-
will be found that it conduCts as well as without va^es the
the eleCtric coating. This, fays Mr Cavallo, proves fub^a"ce of
that the eleftric matter paffes through the fubdance COndudt°rS*
of the metal, and not over its lurface. A wire
adds he, continued through a vacuum, is alfo a con¬
vincing proof of the truth of this affertion. Even here,
however, the proof, if impartially confidered, will be
found very defective. It is a faCt agreed upon by all
philofophers, that bodies which to us are apparently
in contaCt, do neverthelefs require a very confiderable
degree of force to make them aCtually touch one ano¬
ther. Dr Priedley found that a weight of fix pounds
was neceffary to prefs 20 drillings into clofe contaCt,
when lying upon one another on a table. A much
greater weight was neceffary to bring the links of a
chain into contaCt with each other. It cannot be at
all incredible, therefore, that a wire, though covered
with fealing-wax or rofin, fhould dill remain at fome
little didance from the fubdance which covers it.
M. Coulomb proves that in an overcharged conduct¬
ing body, the fluid does not penetrate into its fub¬
dance, but diffufes itfelf merely over the furface.
By means of a very delicate eleCtrofcope, he examin¬
ed pits made in -a conducting body of various depths,
and found that in the fliallowed of them there was no
fenfible eleCtricity j whence he naturally draws the con-
clufion, that the eleCtr.city in fuch bodies does not ex¬
tend beyond the furface. The reader may fee a defcrip-
tion of the eleCtrofcope employed, and a detail of the
experiments in the Memoirs of the French Academy
for 1786, p. 72, or the Journal de Phyjique, vol. ii. (of
the feries by Delametherie), p. 236.
Dr Robifon repeated Coulomb’s experiments with the
fame refults.
Another opinion that has been maintained with re- Electricity
fpeCt to eleCtricity, is that it is the fame with light. The differs from
principal argument for the identity of eleCtricity and bgAt-
light feems to be that bodies are impregnated with the
latter by means of the former, and indeed that light
commonly appears when the eleCtric fluid paffes in any
quantity from one body to another.
Another reafon given for their identity, is, that both
move with inconceivable velocity.
A ftrong argument againit the identity of light and
eleCtricity,
Chap. II. ELECT
Theory of ele&ricity, is that the former paffe* through glafs and
Electricity. other tranfparent eleftrics, which feem to be imper-
v meable to the eleftric fluid.
As to the impregnation of opaque bodies with light
by means of ele&ricity, this is the effect of chemical de-
compofition, as will prefently appear, and is really pro-
- duced by light itfelf.
Ele'aric What has been now faid is, we think, fulhcient to
fluid proba-prove, that the ele&ric fluid is neither caloric nor light,
bly a com- ;gut appearance of caloric and light, in many cafes,
pound. fhews that there is an intimate connedtion between them
and the eledtric fluid. In Ihort, they feem to form part
of its compofition-, and wre are inclined to conlider it as
a compound, containing caloric and light, and probably
fame peculiar conftituent, to which wTe give the name
of eledlricity. This opinion is not new ; it was the hy-
pothefis of Mr James Ruffel, wrho filled the natural
philofophy chair at Edinburgh, above thirty years
362 ago.
Hypothefis Mr Ruffel confidered the eledlric fluid as a compound
of Profeffor of feveral others, containing particularly elementary
Ruffel. fire? from which it derived its great elafticity or powrer
of repullion. The elafticity of the eledtric fluid he fup-
pofed to differ from that of air, in adting at a diftance ;
W’hereas the adtion of the air is only on adjoining par¬
ticles. Hence bodies that contain more eledtric fluid
than the fpaces around them, have a tendency to re¬
pel each other.
Mr Ruffel confidered the charadteriftic ingredient of
the compound, i. e. the eledtricity, as united to the
other conftituents by chemical affinity, or, as. it
was then called, EleEiive AttraBion. This attradtion
adts at all diftances, but not exadtly according to the
fame law, as the repulfive powder of the elaftic fluid 5
and in general, while in this ftate of compofition, coun-
teradls the repulfion of the eledtric particles. Again,
the eledtricity attradts the particles of other bodies, but
with different degrees of affinity. Non-eledtrics or
condudtors are attradted by it at all diftances, but elec¬
trics only at very fmall and imperceptible diftances,
and at fuch diftances only its owm particles attradt each
other.
Hence this compound fluid repels its owm particles at
all confiderable diftances, but attradts them wffien very
near. It alfo attradts condudtors at all diftances, but
eledtrics only wffien very near. The appearances of
light and heat were confidered by Mr Ruffel as proofs
of a partial decompofition, and as evincing the prefence
of elementary fire : the peculiar odour of the eledtric
fpark, and the effedt produced in certain inftances on
the organ of tafte, were alfo regarded as proofs of chemi¬
cal decompofition, and of the compound nature of the
eledtric fluid.
Again, condudting bodies containing eledtric fluid,
if forced very near, attradt each other j otherwife
they repel each other. Electrics contain the eledtric
fluid in confequence of the eledtricity exifting in the
compound: a part of this muft be attached to the furface
of the eledtric, but not in its elaftic ftate, fince when
brought fo near as to be attradted, its particles are fub-
jedted to their own mutual adtion, and hence the re¬
pulfion occafioned by its combination wffiffi the other in¬
gredient of the fluid is overcome by the redoubled at¬
tradtion } the eledtric fluid is thus partially decompofed,
R I C I T Y. ■ 757
and the eledtricity attaches itfelf to the furface of the Theory of
eledtric. Tl}us the eledtric fluid may appear in two Eledtncity^
ftates ; elaftic when entire, and unelaftic when partial¬
ly decompofi d.
The eledti ity may be rendered unelaftic in feveral
ways, as by iridtion, by which the eledtric fluid con¬
tained in the air is forced into clofer contadt, thus pro¬
ducing a decompofition of the fluid, and caufing its
eledtricity to unite with the furface of the rubbed body.
This operation may be compared to the forcible wet¬
ting of a dry fponge, or of fome pow’der, as that of the
puff' hall, wffiich, wffien dry, do not eafily imbibe moif-
ture *, but when wetted by mechanical compreffion, re¬
tain it very forcibly. The eledtricity unites with bo¬
dies in this wray during feveral operations of nature, as
in the melting and cooling of fome fubftances in con¬
tadt with eledrics j and it may be thus forcibly united
to the furface of eledtrics by means of metallic coatings,
into which the fluid is forced by the Ikilful manage¬
ment of its mutual repulfions. This operation, again,
was compared by Mr Ruffel to the condenfation of the
moifture of humid air on a cold pane of glafsj and the
evacuation of fluids from the other fide of the coated
pane he compared to the evaporation of the moifture
from the other fide of the cold pane, in confequence
of the heat that wTas extricated from the condenfed va¬
pour.
The analogy that exifts between eledlricity and ca
loric, has induced fome to apply to the former the
dodlrine of capacity, fo ingenioufly applied to caloric
by Dr Crawffiord. This dodlrine feems to be one of
the fundamental principles of Mr Wilkinfon’s theory
of eledlricity 5 the fubftance of which is contained in
the following extradl. 353
“ From fome experiments, I am induced to fuppofe, Mr Wilkin- ~
that eledlricity is univerfally diffufed, but not equally ; f°n s hypu-
that thofe bodies are the bell condudlors which containthe ls‘
the greateft quantity, and thofe the beft non-conduc¬
tors wffiich contain the leaft.—Thus metallic bodies are
the beft condudlors \ all fluids, except air and oil, are
alfo condudlors. The difpofition in the body to retain
eledlricity may be termed its capacity.
When condudling bodies undergo any change, if by
fuch change their capacities become altered, then figns
of eledlricity are evinced.
If the change ffiould be of fuch a nature, that their
capacity for eledlricity becomes increafed, the fubftance
will be in a ftate of abftradling it from furrounding
bodies, and therefore wall evince negative figns; the
fame as frigorific mixtures produce negative figns of
heat.
If, in the change it undergoes, the capacity of the
fubftance for eledlricity is diminiffied, it gives out a
portion of its natural quantity, and evinces pofitive
figns, or a ftate of fuperabundance.
When any fubftance, in the change it undergoes,
gives out eledlricity, it becomes proportionally dimi-
nilhed in its condudting powers ; fo, on the contrary,
wffien it acquires an increafe, it increafes alfo its powers
as a condudtor.
Thus a metallic fubftance, which is a good con-
dudtor, when oxidated is a very imperfedt one. In
the change from its reguline ftate to a calx, eledlricity
is given out.
This
758 ELECT
of This capacity for eleftricity is not regulated by any
■Eledtncity. knC)Wn laws, fuch as the denfities or the fpecific gravi¬
ties of the bodies.
In many iubftances, the condudiing power feems to
depend on the addition of other principles ; thus tvood,
when a condudlor, is fo in confequence of the tnoilfure
it contains j when deprived of it by drying, it refills
the pall age of eleftricity.
What this peculiar change may be, is difficult to
conceive 5 but when eleflric bodies become partial
conduflors, it feems to be effefled by the agfency of
heat.
When the preffing aftion is very confiderable, as in
the cafe of metallic bodies, great quantities of heat are
extricated. Thus a nail, when Itruck violently, foon
exhibits figns of confiderable warmth; the caloric in-
fufed in its interltices is exuded on the furface, in con¬
fequence of the approximation of the conftituent par¬
ticles of the iron.
Whether the caloric diffufed in the interfliceS, of
combined wfith the body, is given out by preffute, is a
fafl difficult to determine. Thofe fubllances which are
non-condu£tors, and confequently capable, from ex¬
citation, of giving out figns of eleftricity, do not all of
them lofe their power, when freed from the rubbing
a ft ion. Thofe bodies which are ufually termed refin-
ous, continue for a certain fpace of time in their con-
mints of dufUng Hate, until they are equalized with the fur-
GalLnifm, rounding air y and, continuing in a difpofition to ab-
vol. ii. Itraft eleftricity from furrounding bodies, will there-
364 fore evince negative figns (/)”.
tionsb^Mr ^0<^”ne bodies having different capacities
{LMorgan^05' okfiricity was ingenioully employed by Mr G.
Morgan to account for the effefts produced on defines
by friftion.
“ If (fays he) we admit the corporeal nature of that
which is hence with accuracy called the eleftric fluid,
let us attend to the neceffary confequences of what we
•admit:—ill. That the define fluid, like all other cor¬
poreal fubftances, is capable of attracting, and of being
attrafled. 2d. That in confequence of this capacity,
it enters into an union with other bodies, and that as
the nature of the fubltances to which it is united may
vary, fo the degree of force by which it is united may
fliow an equal variety. 3d. That when the eleftric
fluid is feparated from any body, this feparation mult
be the effeft of leffening the force by which it was
united to that body, and thus giving the attraflive
force of another body the fuperiority; or it mult be the ef¬
feft of very much increafing the force of the third bo¬
dy, and thus ddtroying the equilibrium.
Suppofe that any body, A, ffiould be capable of unit¬
ing to itfdf, or fuppofe the law of its conftitution were
fuch as to admit of its attaching, fifty particles of the
deftric fluid to itfdf, when near or in contaft with
R I C I T t. PartlV-
another body, B, which likewife has an attraflion to Theory of
thofe particles j now, in cafe any fuch change ftiould Eleftrkity.
take place as would add twenty particles to B, and
leave thirty only in A, this change, it is evident, mult
proceed either from a diminution of A’s attrafting
force, or from an adequate increafe of force in B.
Having deduced, from the corporeal nature of the elec¬
tric fluid, fuch confequences as fhow that when it is fe¬
parated from n body, it mult proceed from a diminu¬
tion of attractive force in the body that yields, or an
increafe of the fame force in the body that takes ; let
us now examine how friCtion is likely to be the caufe
of fuch changes.
By attending to the nature of friction, we fliall find
it to be nothing more than a lucceffion of preffure or
contads of the different parts of different fubftances
againft each other : and the queftion in the prefent
cafe is this p—-whether contaCt is neceffarily attended
with a change of attractive force in the different fub¬
ftances which are brought together > or whether the
clofe union of a particle of filk, hair, leather, &c. to
a particle of glafs, may be attended wdth a change of
capacity in thofe bodies to retain the eleCtric fluid ? 
If this queftion be admitted, I think the particular
mode in which friction operates is eafily difeovered.
Briefly my idea of the manner in which friCtion ope¬
rates, is this : when two eleCtrics are preffed clofely to¬
gether, while they continue together, they become ca¬
pable of taking more, or retaining lefs ; and if this be
allowed, I think the various appearances of bodies in a
ftate of excitation are eafily accounted for.
However, it may be alked, if the change produced
in the furfaces of two bodies be the effeCt merely of
bringing the bodies nearer together 5 why does not
contaCt alone produce the fame effeCt ? I mull anfwer,
that the feveral inftances of fpontaneous eleCtricity enu¬
merated by Wilcke, vEpinus, and others, appear to
me to be fo many evidences of the preceding theory.
In thefe inftances we fee the excitation of furfaces
take place in fuch circumftances as will not rationally
admit of any other caufe than fimple contaCt.
It is evident, I think, that contaCt alone is adequate
to the production of eleCtricity. I would add, that in
the only cafe where contaCt may be applied moft com¬
pletely, eleCtricity is produced in a moft remarkable
degree.—By Bennet’s new eleCtrofcope, we find that
the flighteft evaporation (which is certainly the union
of watery with aerialjparticles) produces immediate figns
of eleCtricity. How rationally all the eleCtrical appear¬
ances of our atmofphere may be aferibed to the fame
fource, will be ihown more fully hereafter.
Before I quit this fubjeCt, I would explain to you
the reafons why, in many cafes, agreeably to th6 pre¬
ceding hypothefis, friCtion is neceffarily much more
powerful in its effeCts than preffure.
Suppofe
(/) Mr Coulomb endeavours to prove that the eleCtric fluid is not diftributed among conducting bodies in con¬
taCt by chemical -affinity, but merely by its repulfive motion.
When two bodies, equal and fimilar, placed in contaCt, are tolerably perfeCt conductors, fuch as the metals, the
eleCtricity communicated from one to the other is in an inftant divided equally between them 5 but when one of
the bodies is an imperfeCt conductor, as a plain of paper, it will take fome time before the paper receives the half
of the eleCtricity of the metal. In all cafes, however, the eleCtricity is equally divided. Vid. Mem. dePAcad.
Roij. de Paris, pour 1786. p. 69.
Chap.
II. ELECT
Theory of Suppofe A to be a particle of filk, brought into
Electricity^ contaCt with a particle of glafs, which I call E j by the
v increafe of attraclion eonfequent upon the union, the
combined bodies become capable of attrafting a por¬
tion of the fluid, which I fay, is equal to five. Now
A is no fooner feparated from E, than another particle
of filk comes in contaft, and produces a fimilar effedf.
The portion accumulated is now ten. A third comes
into fucceffive contact with B, and adds to the accumu¬
lation 5 and while the rubbing goes on, a feries of fuc-
ceflive effedts is produced by a feries of fucceffive unions
and feparations •, for A is no fooner feparated from E,
than it is brought into that date in which it wTas be¬
fore the union, and consequently difpofed to part with
what it gained by the union. Now if you fuppofe A
and E, inftead of being fingle particles, to be fiirfaces,
all of whofe parts operate at the fame time, you may
eafily perceive how the effedt would be increafed.
In the preceding cafe, I defcribed the capacity of
A and B to be enlarged by their union. If it had
been leflened, the fubl'equent effedts would have been
fufficient; for, in fuch a cafe, after the diffoiution of
their contadl, they would be difpofed to receive or re¬
take what they had loft by their union. But I will
fpeculate no longer on the confequences of fridfion, as
^_ , elucidated from the fuppofed corporeal nature of the
LeBures eledlric fluid, and from the changes fuppofed to take
vol. i. place on the attradlive force of difterent bodies when
brought into very clofe contadl with each other*.”
Brugnatelli Sig. Bru^natelli, from the chemical properties of the
fuppofes the eledfric fluid, and, from feveral experiments v/hich he
has made upon the fubjedl, concludes that it ffiould be
ranked among the acids. This fluid, fays he, red¬
dens the tindture of tumfole, which as the fluid diffi-
pates returns again to a blue colour •, it penetrates the
metals, oxidates them, and produces hydrogen gas.
In fine, it poffeffes all the properties of an acid. He
therefore denominates it the electric or oxi-eleffric acid,
and of courfe the falts which are formed by its combi¬
nation with falifiable bafes, are called eleclrats. On
fome of thefe he makes the following obfervations.
1. The elcElrat of gold is formed of fmall, brilliant,
and tranfparent points.
2. The eleclrat of filver confifts of fmall prifmatic
cryftals, terminated by fix-fided pyramids, which are
limpid and tranfparent, and ftrongly refiedt the light.
They are taftelefs and infoluble in water.
3. The eledirat of copper confifts of cubical tranfpa¬
rent cryftals, which diflblve in the jacid with effervef-
cence. The cryftals are of a beautiful green colour.
4. The eleBrat of iron is of a reddiffi yellow colour,
and opaque.
5. The eleBrat of zinc is opaque, and of a grayiffi
colour.
The eleBric acid, according to this author, is not de-
compofed, when it oxidates the metals, but the oxygen
required for their oxidation, is derived from the water
employed in his experiments.
Having thus confidered pretty fully the chemical na¬
tion of the ture of the eledlric fluid, we ftiall return to its mechani-
ele&ric cal properties, and endeavour to afcertain the law by
fluid. which its particles adt on each other, and haw it is
diftributed in bodies of various figures, and in various
relations.
It was long a defideratum among eledlricians to dif-
elcdlric
fluid to be
an acid.
365
Law of ac-
R I C XT Y. 759
cover the law of adlion according to which the particles Theory of
of the eledlric fluid attradl and repel each other. Ai-
pinus, we have feen, ftates no other law than that the
adlion decreafes according as the diftance increafes.
Mr Cavendifti fufpedied, but did not prove either by
demonftration or experiment, that the adlion of electri¬
city was, like that of gravitation, inverfeiy as the fquare
of the diftance.
Lord Stanhope attempted to prove that this was the
law of eledlric adlion, both experimentally and mathe¬
matically, and concluded from the refult of both his
experiments and reofoning, that the fuppofition was juft.
But Dr Robifon did not confider the experiment of
Lord Stanhope, as fufficiently accurate, or fufficiently
detailed, to warrant the conclulions that his Lordihip * Mahon's
had drawn *. Principles
That eminent philofopher, nearly 40 years ago,
a fet of experiments for afcertaining this law, and they anr^S
were attended with refults fimilar to thofe of Lord vi.
Stanhope. 3^7
Dr Robifon’s experiments were made with the affif- Afcertained
tance of his excellent eledlrometer, which we have
fcribed in N° 206. The mode of uftng this inilrument Robifon.
is as follows.
The body whofe eledlricity is to be examined is con-
nedled with the eledlrometer by a wire, the end of
which is inferted into the hole at F, and made to touch
the end of the needle. Now the index is to be turned
to the right by the handle I, till it come to 90. In
this pofition LiV, and confequently CB, is horizontal 4.
and the moveable ball B refts on A and moves with
it. The balls being now eledlrified, the handle is turn¬
ed back till the index arrive at o, from which it fet
out. If during this motion the balls be noticed, it will
be found that in fome pofition of the index they will
feparate. Bring them again together, and again fepa-
rate them, till the exadl point of feparation be afcer¬
tained. This will give their repulfion when in contadl,
or at the diftance of their centres. Then turn the in¬
dex ftill more to the vertical pofition, and the balls
will feparate ftill more. Let an affiftant now move the
long index till it become parallel to the flail: of the
eledlrometer, which will be known by its hiding the lat¬
ter from his view. If the ftalk be poifed, by laying a
weight of fome grains on the cork ball D, till the ftalk
become horizontal and nicely balanced, we know exadlly
the weight that denotes the degree of repulfion that will
caufe the balls to feparate when in the horizontal pofi¬
tion, by computing for the proportional lengths of BC
and DC. Then, by a very Ample computation, we
Avail find the weight denoting the degree of repulfion
with which they feparate in any oblique pofition of the
ftalk, and again, by the refolution of forces, we find
the degree of repulfion with which the balls feparate
when AL is oblique, and BC makes with it any given
angle.
I he intention of Dr Robifon’s experiments was to
afcertain the law of repulfion of two fmall fpheres, as
whatever was the law of diftribution of the particles
in a fphere, which we ffiall confider prefently, the ge¬
neral adlion of its particles on thofe of another fphere
will not differ materially from the law of adlion be¬
tween two particles, if the fpheres are very fmall in
proportion to their diftance.
The refult of the experiments was that the mutual
repuliion
760 ELECT
Jeh<£dt0f repulfion of two fmall fpheres, eleftrified either pofi-
*■' ' y -. tively or negatively, was very nearly inverfely as the
fquare of the diflance of their centres, or a little
greater. Thus, if we exprefs the diftance by x, the law
of repuliion was as nearly as poffible —^—. One of
X%'°6
the balls being much larger than the other appeared to
caufe no difterence in the refults.
Repeating the experiment with balls ele&rified op-
pofitely, and which of courfe attrafted each other, the
refults obtained were not quite fo regular j but the ge¬
neral refult was a deviation from the above law rather
lefs than in the preceding cafe, this being in defedl,
while that was in excefs.
Sir Ifaac Newton has demonftrated, (Princip. lib. i.
pr. 74.) that if particles of matter aft on each other
with a force in the inverfe duplicate ratio of the di-
flances, fpheres compofed of fuch particles and of equal
denfity at equal diftances, will aft on each other ac¬
cording to the fame law. He has demonftrated that
the fame holds in the cafe of hollowT fpherical fliells,
and that thefe aft on each other in the fame manner as
if all their matter were crowded into their centres; and
he has farther demonftrated, that if the law of aftion
between the particles be different from what has been
ftated, the aftion of fpheres or fpherical fhells will alfo
be different.
M. Coulomb of the French academy made a num¬
ber of moft valuable experiments for the purpofe of af-
certaining this point, and obtained the fame refults.
I his diftinguifhed academician has publifhed in the
memoirs of the Royal Academy at Paris for 1784,
17^55 i7S6, and 1787, papers which rank him very
high among thofe who have contributed to advance the
fcience of eleftricity.
In the Memoirs for 1785 appeared the papers that
contain the experiments by which he proved the law of
eleftric aftion. Thefe we cannot here pretend to de¬
tail, but the refult is highly fatisfaftory. They were
made with the afliftance of a very delicate eleftrometer,
the conftruftion of which we {hall defcribe under the
368 article Electrometer.
Approxi- The reader may fatisfy himfelf very nearly of the
mating tx- truth of this law by the following fimple experiment,
penment. ^ IQ2. js ^ convex extremity of an excited
furface. BC is a metallic rod, delicately fufpended on
the point E. CF is defigned to contain any weight
which may be applied to the extremity of the rod.
The apparatus fhould be as light as poftible, and is beft
made of reed and cork covered with tinfoil.
While the furface A is in an excited ftate, B is
brought within a certain diftance of it, and the weight
moved by its influence is carefully obferved. A fimi-
lar obfervation is then made at a fecond, a third, and a
fourth diftance.
Varieties wall be difcovered in the refult of thefe ob-
fervations, proceeding from the impoflibility of keeping
the furface for any confiderable time in the fame ftate
of excitation. Thefe varieties, however, are trifling;
and in a vaft number of experiments, the weight will
diminifh very nearly in the duplicate ratio of the in-
creafed diftance.
We may now fafely conclude that the law of eleftric
aftion is like that of gravitation, fo that eleftrified bo-
R I c I T Y.
Part IV.
dies attraftt or repel each other with a force that is Theoiy of
inverfely as the fquare of the diftance. The afcertain-j;:lc6lr'Cit>-
ing of this important law is of infinite confequence. *"
It affords us a full conviftion of the truth of the propofi-
tions refpefting the aftion of bodies that are over¬
charged at one end, and undercharged at the other.
It renders certain what w e could formerly infer only
from a reafonable probability. We now fee that the
curve defcribed in N° 338. muft really have its convex¬
ity turned towards the axis, and that Z-fss' will alw ays
be greater than ^
We now proceed to confider the manner in which Dftnbli¬
the eleftric fluid is diftributed, wdien it is redundant or*Km of l!)C
deficient in bodies ; and for this purpofe we cannot do pIe<^ric
better than lay before the reader the following feries of Ruld‘
propofitions, chiefly taken from Mr Cavendiih’s paper,
but accommodated to the true law of aftion above laid
dmvn. 37G
Lemma I.—Let the whole fpace comprehended be-Fundamen-
tween two parallel planes, infinitely extended each way,t?1 ProP°fl-
be filled w-ith uniform matter, the repulfion of wdiofe ti0n'
particles is inverfely as the fquare of the diftance; the
plate of matter formed thereby will repel a particle of
matter with exaftly the fame force, at whatever diftance
from it it be placed.
For, fuppofe that there are two fuch plates, of equal
thicknefs, placed parallel to each other, let A, fig. 103,
be any point not placed in or between the two plates ; let
BCD, reprefent any part of the neareft plate; draw
the lines AB, AC, and AD, cutting the fiirtheft plate
in b, c, and d; for it is plain that if they cut one plate,
they murt, if produced, cut the other : the triangle
BCD, is to the triangle bed, as AB1 to Ab1; there¬
fore a particle of matter at A will be repelled wdth
the fame force by the matter in the triangle BCD,
as by that m. b c d. Whence it appears, that a parti¬
cle at A will be repelled with as much force by the
neareft plate, as by the more diftant; and confequent-
ly will be impelled with the fame force by either plate,
at whatever diftance from it it be placed.
Cor. i.—The fame will be true of the aftion of
plates of equal thicknefs and equal denfity, or of fuch
thicknefs and denfity as to contain quantities of mat¬
ter or fluid proportional to their areas.
Cor. 2.—The aftion of all fuch feftions made by
parallel planes, or by planes equally inclined to their
axis, is equal.
Cor. 3.—The tendency of a particle to a plane, or
plate of uniform thicknefs and denfity, and infinitely
extended, is the fame, at whatever diftance it be placed
from the plate, and it is always perpendicular to it.
Cor. 4.—This tendency is proportional to the den¬
fity and thicknefs of the plate or plates jointly. 3-r
Problem J.—In fig. 104. let the parallel lines Difpoiibon
A <7, B £, &c. reprefent parallel planes infinitely ex-'n Para^e^
tended each w^ay: let the fpaces AD and EH be filled I)latc5,
with uniform folid matter : let the eleftric fluid in each
of thefe fpaces be moveable and unable to efcape : and
let all the reft of the matter in the univerfe be fatura-
ted with immoveable fluid. It is required to determine
in what manner the fluid will be difpofed in the fpaces
AD and EH, according as one or both of them are
over or undercharged.
Let AD be that fpace which contains the greateft
quantity
X
Ctiap. 1L
Theory of quantity of redundant fluid, if both fpacts are over-
Eledtricity. charged, or which contains the leaft redundant matter,
‘ if both are undercharged j or if one is overcharged,
and the other undercharged, let AD be the overchar¬
ged one* Then^ firft, There will be two fpaces, AB
and GHj which will either be entirely deprived of fluid,
or in which the particles will be preffed clofe together *,
namely, if the whole quantity of fluid in AD and EH
together, is lefs than fufficient to faturate the matter
therein, they will be entirely deprived of fluid 5 the
quantity of redundant matter in each being half the
whole redundant matter in AD and EH together \ but
if the fluid in AD and EH together is more than fuf¬
ficient to faturate the matter, the fluid in AB and GH
will be prefled clofe together; the quantity of redun¬
dant fluid in each being half the whole redundant fluid
in both fpaces. 2,dly, In the fpace CD the fluid will
be prefled clofe together 5 the quantity of fluid therein
being fuch as to leave juft enough fluid in BC to fatu¬
rate the matter therein. 3dly, The fpace EF will be
entirely deprived of fluid; the quantity of matter there¬
in being fuch) that the fluid in EG ftiall be fuflicient to
faturate the matter therein: confequently, the redun¬
dant fluid in CD will be juft fufficient to faturate the
redundant matter in EF. And 4thly, The fpaces BG
and FG will be faturated in all parts.
Cor. 1.—If the two plates be equally overcharged)
all the redundant fluid will be crowded on the remote
furfaces, and the adjacent furfaces will be in their natu¬
ral ftate.
Cor. 2.—If the redundant fluid in the one be juft fuf¬
ficient to faturate the redundant matter in the other, the
two remote furfaces will be in their natural ftate, all the
redundant fluid being crowded in the ftratum C c</D,
and all the redundant matter being in E e/F.
pifpofitkm Lemma II.—Let B D E and pdi, (fig. 105.)
in a fphere. concentric fpherical furfaces, wdiofe center is D ; if
the fpace B £ is filled with uniform matter, whofe par¬
ticles repel with a force inverfely as the fquare of the
diftance, a particle placed anywhere within the fpace
C b, as at P, will be repelled with as much force in one
direction as another, or it will not be impelled in any
diredtion. This is demonftrated in Newt* Princip. lib. i.
prop. 70. It follows alfo from his demonftration, that if
the repulfion is inverfely as fome higher powrer of the di¬
ftance than the fquare, the particle P will be impelled
towards the centre 5 and if the repulfion is inverfely as
fome lower potoer than the fquare, it wall be impelled
from the centre.
Problem 2.-*—Let the fquare BDE, be filled with uni¬
form folid matter, overcharged with eledtric fluid ; let
the fluid therein be moveable, but not able to efcape
from it \ let the fluid in the felt of infinite fpace be move-
able, and fufficient to faturate the matter therein \ and let
the matter in the whole of infinite fpace, or at leaft in the
{pace BB, whofe dimenfions will be given below, be
uniform and folid : it is required to determine in what
manner the fluid will be difpofed both within and with¬
out the globe.
Take the fpace BZ>, fuch that the interftices between
the particles of matter therein lhail be juft fufficient to
hold a quantity of eledlric fluid, whofe particles are
prefled clofe together fo as to touch each other, equal
to the whole redundant fluid in the globe, befides the
quantity requifite to faturate the matter in B } and take
Vol. VII. Part IL
76f
the fpace BB, fuch that the matter therein fltall be juft ™eory of
able to faturate the redundant fluid in the globe : then , c »
in all parts of the fpace B b, the fluid will be preffed clofe
together, fo that its particles {hall touch each other.
the fpace B /3 will be entirely deprived of fluid; and in
the fpace C b, and all the reft of infinite fpace, the
matter will be exactly faturated.
Cor. I.—If the globe BDE is undercharged, every
thing elfe being the fame as before, there will be a
fpace B£, in which the matter will be entirely deprived
of fluid, and a fpace B /3 in which the fluid will be
prefled clofe together j the matter in B b being equal to
the whole redundant matter in the globe, and the redun¬
dant fluid in B /3 being juft fufficient to faturate the mat¬
ter in BZ>: and in all the reft of fpace the matter will be
exaftly faturated, exactly fimilar to the foregoing.
Cor. 2.—The fluid in the globe BDE will be dif¬
pofed in exactly the fame manner, whether the fluid
without is immoveable, and difpofed in fuch manner,
that the matter ffiall be everywffiere faturated, or whe¬
ther it is difpofed as above defcribed; and the fluid with¬
out the globe wdll be difpofed in juft the fame manner,
whether the fluid within is difpofed uniformly, or whe¬
ther it is difpofed as above defcribed. . 373
Let BC, fig. 106. be a cylindrical conducing body, General it*
and A an overcharged body. Draw be parallel to LC,
and draw B C c, P/>, &c. perpendicular to BC, to ditpofitiorw
reprefent the uniform denftty of the fluid, when BC
is in its natural ftate j and letB</, Cr*, P r, &c. re¬
prefent the unequal denfities at different points, while
it is oppofed to the overcharged body A. Now thefe
ordinates wall be bounded by a line dnr. Cutting the
line bcvxn, a point in the line n N drawn perpendicu¬
lar to N, the neutral point of the condu&or. The
wdiole quantity of fluid in BC will be reprefented by
the parallelogram bj, CB ; but this muft be equal to
the fpace P><Zrnd; again, the redundant fluid in any
portion, as PC or PN, may be reprefented by the fpaces
pt rc, o? tpn, and the deficient fluid in any portion BQ^,
may be reprefented by the fp&ce b dn) q. Now, the ac¬
tion of BC on any body placed near it, will entirely
depend on the fpace contained between the curve line
and the axis be. With refpe£t to this curve, the only
circumftance that we can afeertain, is that variations of
curvature at every point are proportional to the forces
exerted by the fpherical body A •, and are, therefore,
inverfely as the fquares of the diftances from A, as will
be ffiewn prefently. The exafir place of the point n, *
and the length of the ordinates, will vary according to
the diameter of the conductor. We lhall at prefent
confider only the fimpleft cafe, or that where the con-
du&or is of no fenfible diameter, like a very fine wire. 374
Let fuch a {lender conducing canal be reprefented Piftribu-
by AE, fig. 107. and letB£, C C, JL e. &c. reprefent
the denfity of the contained fluid, this being kept ih a Or¬
nate of unequal denfity by its repulfion for fome over- jy uniform^
charged body. Now, a particle at C is impelled in
the direTion CE by all the fluid that is on the fide of
A ; and it is impelled in the direftion CA by all the
fluid on the fide of E. The moving force will arife
from the difference of thefe repelling forces. When
the diameter of the canal continues the fame, this will
arife from the difference of denfity only. Therefore, the
force of the element at E may be expreffed by the excefs
of D </ above C c the aftion at the diftance CD.
5 D Draw
ELECTklClT
I
762
Theory of
TleClricity.
?75 .
Commum
cation by
ftraight
canals.
elec
Draw /3 c 1 parallel to AE ; then the force
clement E may be expreffed by the formula
T
of the
376
By crooked
Canals.
Sn CA18 thC f°rC- repClHng the particle ^ the direc-
^Talve CF=CD; the force at F will be expreffed by
^ °r cl* Xy an<^ t^s Poree alfo impels the par¬
ticle in the direftion C A. The joint action of the two
. a d f <p •
18 ~7t~ X' U ice were a Alight line, //2-f fp
would always be proportional to cl, and might be ex¬
preffed by w Xc m denoting feme numbe? that ex-
prefles what part of c$ the fum of d2 and f<p is equal
to ffppofe TV, &c. But in the prefent cafe
^ not always proportional to r for ^ does
not mcreafe fo fell as. c while fcp increafes fafter
\\e may, however, without any fenffole error, exprefs
tne accelerating force tending towards A, in the neigh¬
bourhood of any point C, by that is, by
"'IT VVhich iS the fluxI°n °f the area of a hyperbola
wlD,/G,A0fwhVChiCu,.andCK are ^ptotes. The
whole adion of the duid between F and D may be ex
[he fmall7 ^ Henc^ the adion of
- e 1 mailer conceivable portion of the canal that ad-
Kei °Ten °r thC differeUCe °f the a<aions
all h!v e fmentS’ is eclual to the aftion of
f yond it. Ihe ffate of compreffion is therefore
fcarcely aftefted by any thing at a fenfiblc diftance
in an indefinitely
ceed to examine, the communication of elearicity bv
means of condu6bng canals^ which forms one of the
moft important parts of the theory.
‘ th ^ U.S %P°fe that the body A communicates by
the canal EF,.with another body D, placed on the con-
trary fide of it from B, as in fig. i08. and let thefe
tno bodies be either laturated, or over or under¬
charged 5 and let the fluid within them be in equili-
bno. Let now the body B be overcharged: it is
P air\vrvr fon!e fluld wil1 be driven from the nearer
part MN to the further part RS; and alfo fome fluid
will be driven from RS, through the canal, to the
body D ; fo that the quantity of fluid in D will be in-
crea ed thereby, and the quantity in A, taking the
whole body together, will be diminifhed : the quanti-
ty in tne part near MN will alfo be diminiihed : but
whether the quantity in the part near RS will be dimi-
mfhed or not, does not appear for certain; but proba¬
bly it will be not much altered.
Cgr.—Jn. like manner, if B is made undercharged,
fome fluid will flow from D to A, and alfo from that
part of A near RSr to the part near MN.
Suppofe now that the bodies A and D communicate
/ the bent canai MPN np m (fig. 109.) inftead of
the ftraight one EF: let the bodies be either faturated
or over or undercharged as before j and let the fluid be
•at reft ; then, if the body B is made overcharged, fome
R I C I T Y. partIV
So^i’fR11 T °Uh°-fAf“0D; Pr0v!ded there- Theory of'
pu lion of B on the fluid m the canal is not too great EleAticity.
1 he. repulfion of .B on the fluid in the canal, wilfat'    
firft drive fome fluid out of the leg MP/, m into A
arid out ofiVI> « into D, till the quantity of fluid in
that part of the canal which is neareft to B is fo much
imimfhed., and its repulfion on the reft of the fluid in
the canal is fo much diminifhed alfo, as to compenfate
he repulfion of B : but as the leg NP/,* is longer
wilT °ther’ ^ rrePulflon ofB 011 the1 fluid in it
ofA ^°n^uent7 ^ fluid will runout
omf ffne PnnciPle that water is drawn
out of a veffel through a fyphon : but if the repulfion
th Bd°-i hC 7 tbe Canal 18 fo great as to drive all
in tArfe-M?^ 6 /PaCe GPH/> G’ f° dlat the flu^
n the leg MG/>m does not join to that in NH b n •
en it is p.aui that no fluid can run out of A into D •
any more than water will run out of a veffel through a
fyphon, if . the height of the bend of the fyphon above
wLT^l't U,e Vefld’ 1S greater than that to which
Water will rile in vacuo.
I his is. Mr Cavendifli’s reafoning j but Dr Robifon
objects to.it,. that m thefe cafes the fluid does not move
on the principle of a fyphon, and that there is nothing
to prevent the fluid from expanding in GPH. He was
therefore of opinion, that it would always move from
A to D over the bend.
C°r.—-If AB is made undercharged, fome fluid will
run out of D into. A j and that though the attradion
of n on the fluid m the canal is ever fo great.
We fhall now confider the adion of eledrified bodies A J77 r
iWt C2mmUnIcation’ in fomc of the moft pla1eon°aa
mportant cafes. . But, as we are confined in our limits ftraight
and have much important matter yet to treat of we, canal*
muft. content ourfelves, with enumerating fads without
proving them by rigid demonftration.
Let AC* fig no. reprefent a thin conduding
plate feen edgwife, to the centre of which the flender
canal CP is perpendicular. It is required to determine
the adion exerted by the fluid, or matter, uniformly
dilpoled over the plate, on the fluid moveable in PC >
• V P °,dnd tbe a^on °f a particle at C on the fluid
in the whole canal. Join AP, and let CP be denoted
by *, AP by rj and AC by r. Alfo, let /reprefent
the intenfity of adion at the diftance x of the fcale
irom which the lines are meafured.
The adion of A™ P is and it may be demon-
ftrated that the adion of A on the whole of CP is
2. To find the adion of the plate whofe diameter is
A * on a particle at P.
Let * denote, the area of a circle whofe diameter is
’ I he adion required will be expreffed by the
fluent
= 1.
Cor.—If PC be very fmall in comparifon of AC
the- adion will be nearly the fame as if the plate was
mnnite-
3. To find the adion of the plate on the whole
column. This will be expreffed by the fluent if a
(x+r—y). /.
Our
Chap. II. ELECT
Theory of Our mathematical readers, who are familiar with
Electricity. t]le method of fluxions, (and to no others will thefe
y theorems be intelligible), will readily fee the meaning of
thefe expreflions.
The following geometrical conftrufHon will render
the aftion of the plate for the whole column, or its parts,
more familiar, and more eafily remembered.
Produce PC till CK is CA, and with the centre
P, defcribe the arch AI, eroding CK in I. Then the
electrical aclion will be exprelTed by if ay, IK; and
this expreflion reprefents a cylinder wrhofe radius is i of
the fcale, and whofe height is — 2 IK.
Again, about the centre />, with the diftance p A,
defcribe the arch A i, cutting CH in i. Then we have
2/tfXfK, exprefling the action of the plate on the
column Cyi, and/tf X I exprefling its a6tion on P />.
By the formula if a x IK, is meant, that the adtion
exerted by the w'hole plate on PC is the fame as if all
the fluid in the cylinder expreffed by « x 2 IK were
placed at the diftance from the adtiug particle denoted
by 1.
37* Cor. 1.—If PC is very great compared with AC,
the adtion is nearly the fame as it would be if the
column were infinitely extended.
379 Cor. 2.—If befides, another column /» C is very
fmall wrhen compared with AC, the adfion on PC wall
be to that on /> C, as/> C to AC nearly.
The redundant fluid cannot be uniformly diffufed
over the wdrole plate, as we have hitherto fuppofed,
fince the mutual repulfion of its particles will render it
denfer at the circumference. As it is difficult to de¬
termine the variation of denfity, we ffiall only ftate the
refult of the extreme cafe, where the whole redundant
fluid is Crowded into the circumference of the plate.
.580 Xhe adiion of the fluid in the canal is now
and the whole adlion of the fluid crowd-
JSi
•38.2
ed into the circumference will be f o r1 y \ -^
' ' r!/ J
T=far(^--—This may be thus reprefented geo¬
metrically. Defcribe the quadrant C b BE, crofting
AP in B, and Ap in b. Draw BD and b d parallel
to PC. Now', PE is —y—r, and DCcrr^—). The
expreffion fa r ^ j will therefore denote a cylin¬
der whofe radius is I, and height DC, multiplied byjfi
Again d C wall be the height of the cylinder expref-
fing the adlion on p C, and D d that of the cylinder ex-
preffing the adlion on P/>.
Cor. i.—-If CP be very great compared with CA,
D is very near to A, and I to C, and CD has to IK
very nearly the ratio of equality.
Cor. 2.—But if the column /> C is very fliort, the
adlion of the fluid uniformly diffufed over the plate, is
to the adtion of the fluid crowded into the circumference
nearly as 4AC to p C.
From this corollary wTe fee that the recefs of the
fluid towards the circumference, has a much lefs effedt
on Ihort columns than on long ones, i. e. the adlion in
the former cafe will be much lefs diminifhed. Any
external force that tends to impel fluid along the canal,
and from thence to diffufe it over the plate, will impel
R I C I f t. 76.5
a greater quantity to the plate when the fluid of the Theory at
plate is crow'ded into the circumference, than if it were Eledtricity.
uniformly diffufed over the plate, and this difference ~v
will be greater wffien the canal is ffiort.
Laftly, When KL is equal to AP, or PL to Ki, 3D
the repulfion exerted by the whole fluid of the plate,
colledled in K, on the fluid in the canal CL, is equal
to the repuliion of the fame fluid, when crowded into
the circumference, on the column CP.
Cor. 1.—When CP is very long in comparifon
with AC or KC, the adlions of the two fluids in both
the above lituations is nearly equal.
Cor. 2.—The adtion exerted by the whole fluid on
the column CP, wffien uniformly diffufed, is to its adtion
wdien colledted in K, as 2 IK to CD.
Cor. 3.—If CNO be a fpherical furface, or a fphe- 3?4
rical ffiell, of the fame diameter and thicknefs with the
plate A a, and containing redundant fluid of uniform
denfity, the adtion exerted by this fluid on the column
CL is equal to twice the adtion of the fluid on the
column CP, when the fluid is uniformly diffufed over
the plate, and to four times its adtion on the fame
column, when it is crow'ded into the circumference.
Let there be two circular plates, reprefented edgewife Adlion of
at DE, //e, fig. HI. or two fpherical fhells ABO,wvoplates
ab 0, of the fame diameters and thicknefs with theor fi)*ieres
plates, containing redundant fluid of uniform denfity,
and let them communicate with ftraight canals OP, o/>,canals.m C
infinitely extended, perpendicular to their furfaces and
palling through their centres, and let the fluid in thefe
canals be of uniform denfity and equally diffufed.
It may be demonftrated that the repulfions exerted
by the fluid in the plates or fpheres on the canals are
as the diameters of the plates or fpheres.
Cor. 1.—When the canals are very long compared 3S6
to the diameters of the fpheres or plates, the repulfions
are nearly in the fame proportion.
Cor. 2.— The more the length of the canals dimi- 387
nifhes wffien compared with the diameters of the plates
or fpheres, the more the repulfions approach to equa¬
lity.
Cor. 3.—When the denfity of the fluid in two fphe- 3SS
rical (hells is inverfely as their diameters, the repul¬
fions of the contained fluid on a column of fluid infi¬
nitely extended, will be equal.
Cor. 4.—When the quantities of redundant fluid in 3S0
two fpheres are proportional to their diameters, the re¬
pulfions exerted by them on a canal infinitely extended
are equal.
Cor. 5.—If tliere be two overcharged fpheres, or 39s
fpherical (hells, as ABO, 0 « £, fig. 11 2. that commu¬
nicate by a conducting canal infinitely extended, the
quantities of redundant fluid they contain are propor¬
tional to their diameters : and they will be nearly fo if
the canals be very long.
Cor. 6.—When the fpheres of conducing matter 35i
?Ltt in equilibria, the preffures exerted by the fluid on
their furfaces are nearly proportional to their diame¬
ters.
It follows from this corollary that the tendency of
fluid to efcape from fuch fpheres is, exteris paribus,
inverfely as the diameters.
Let there be four circular plates, as HK, AB, DF, Important
LM, fig. 113. equal and parallel to each other, andcare of
let two of them, AB and HK, communicate by an in-Plates’
5 D 2 definite
764
ELECT
T.'i^ cana^ GC perpendicular to their planes and
’- e^ncity. paffing through their centres j let DF and LM commu¬
nicate in like manner by the canal EN, both canals
being in the fame ftraight line: let HK be overcharged,
and LM juft faturated. It is required to determine
the difpofttion of the fluid, and its proportion in the
plates, fo that the above condition may be poflible and
permanent, while all is in equilibrio ? 1
As HK and AB communicate and are equal, as
HK is overcharged, AB will be fo abb, and in the
fame degree, and the fluid will be fimilarly difpofed in
both. HK and AB being in this fituation, if DF and
LM be brought near them to within the diftance CE,
as in the figure, the redundant fluid in AB will aft on
the moveable fluid in DF, and force feme of it along
the canal EN into LM, rendering this latter over¬
charged. Nowq if this redundant fluid in LM be ta¬
ken off, the repulfion which LM was beginning to
exert on the canal NE, will be diminifhed or deftroyed.
Hence, more fluid will move from DF into LM, and
this will again be overcharged. The redundant fluid
in LM may again be taken off, but in lefs quantity
than before, and fo on repeatedly, till no more can be
taken off. DF will thus be rendered undercharged, or
will contain redundant matter. This will aft on the
fluid in GC, and attraft it from G, and confequently
the fluid will now move from AK into AB, by which
HK. will be rendered lefs overcharged, and AB more fo
than at fir ft. The thus increafed redundancy of fluid
in AB will aft more ftrongly on the moveable fluid in
DF, and repel a part of it into LM as before. DF
will thus be again rendered deficient, and by its re¬
dundant matter will again aft on the canal GC. Thus,
by repeatedly touching LM to take off the fluid driven
into it from DF, or by allowing LM to communicate
with condufting bodies, an equilibrium will be pro¬
duced ; and when this is the cafe, HK contains a cer¬
tain quantity of redundant fluid, AB contains redundant
fluid in a greater degree, DF contains redundant matter,
and LM is in its natural ftate. The problem may now
be reduced to this. To find what proportion the re¬
dundant fluid in HK bears to that in AB, and what
proportion this latter bears to the deficient fluid in DF ?
To determine thefe proportions it is neceffary that,
I ft, The repulfion exerted by the redundant fluid in
AB on the fluid in EN be precifely equal to the at-
traftibn exerted by the redundant matter of DF on the
fame canal.
2dly, The repulfion exerted by the redundant fluid
in HK on the whole fluid of the canal GC, balances
the excefs of the repulfion of the redundant fluid in AB
on GC above the attraftion of the redundant matter of
DF on the fame canal.
If we call the redundant fluid in AB,y; the redundant
matter in DF, m ; and the redundant fluid in HK,/':
as the fluid in HK and AB is fimilarly difpofed, (they
being equal), and as it is probable that the redundant
fluid in AB, and the redundant matter in DF, are fimi-
Jarly difpofed, it follows, that their aftions on the fluid
in the canals will be fimilar, and proportional to their
quantities nearly.
Let 1 be to », as the repulfion exerted by the fluid in
AB on the fluid that would occupy CE, to the repul-
/on exerted by the fluid in AB on the fluid in EN or
CG.
R I C I T Y.
Tart IV.
AB afts on EN with the force/x («—x) j and DF Theory of
afts on EN with the force m n ; but thefe aftions muft
balance each other, as LM is inaftive. Therefore Y
/X («—and ni— /x ———.
n
If/repels the fluid in CG with the force /«, m at-
trafts the fluid in CG with the force m X (n—I) : but as
s (n—I)z
m —f X   the attraftive force of m for CG
will be /x
O—i)*
X(«—1) : Therefore the repulfion
of / is to the attraftion of m, as /« to / X ——
n
—fn1 :/ X (»—i)a=«* ; n—1*.
Let r denote the repulfion of /, and a the attraftion
of m; then r : a—n' : {n—1 )a j and r : (r—a^—n' : nx
—(n—1 ')i~n1 : (2«—1).
But the repulfion of f = r — a \ therefore :
<>-.)=/: and/' =/x (~) ; or /=/'
x(—)•
V 2n—1)
If we fuppofe «* much greater than 2»—1, we fhall
have the quantity of redundant fluid in AB much great¬
er than that in HK. ^
When EC is very fmall in proportion to AC, it will Prodigious
appear, on referring back to N° 382. that 1 is to «a5cu’,lula-
tion and
nearly as CE : CA j and confequently nzz nearly.diffiPation
CE ■' of redun-
When this is the cafe, « is a confiderable quantity jdant
and there is fo little difference between — and —-—
2n TJi—1
that we may take the former for the latter without any
material error. Now wre have /=/' x - very nearly.
Suppofe AC to reprefent 6 inches, and CE ^T-fh of an
inch, we fhall have n~\ 2a and/=60/', or more ex-
aftly/'=/_^_, =£4,400 =;N6
. \2«—I 239 )
This, it will be remembered, reprefents the redundant
fluid in HK j hence it will appear how great muft be
the redundancy in HK.
Again, when AB and DF are very near, n is a
large number, and the deficiency in DF is nearly equal
to the redundancy in AB. In the above example m is
fgths of /', as m =/X [n—1).
But though there is this great deficiency in DF, and
redundancy in AB, DF is not eleftrical on the fide
next LM, nor is AB more eleftrical than HK 5 in
fhort, this cafe affords another example of bodies being
neutral while redundant or deficient, in addition to
what was advanced in N° 313, 314.
It will readily occur to the reader, that cafes exaft-wit^„t
ly fuch as we have now ftated never happen in the any fenfibl#
courfe of experiment $ but when the canals are very eledlrical
long in comparifon of the diameters of the plate, andeffeC4*
when AB is very neat DF, the proportions will not
greatly vary. #
We have been very particular in the examination of Mode of re-
this cafe, becaufe; it is of great importance, and will ftoring the
aflift us in explaining fome of the principal phenomena/qu‘llbliui11
To prepare for fuch an application of it, we fhall herCgrets?
/late
Chap.
396
At once.
   XT. " ELECT
Theor^ of ftate fome fimplc confequences of this combination of
Sledfricity. plateS. , j
'"'v ' If AB be touched by any body, this body will re¬
ceive from it a part of its redundant fluid, but only a
part j for only fo much- fluid will quit AB as is fuffici-
ent to render it neutral, while the touching body com¬
municates with the ground. This will happen till the
redundant matter in DF attracts fluid on the remote
fide of AB as much as the redundant fluid in AB re¬
pels it. The repulfion of AB on EN is now diminilh-
ed, the attra&ion of DF will therefore prevail, and this
wTill be no longer neutral. If noiv DF be touched, it
may again be made neutral with refpeft to EN j but
AB will again repel the fluid in CG, and being re¬
dundant on that fide will again become eleftric. AB
being touched again, lofes more fluid, and DF be¬
comes eleftric by deficiency. Ihus by alternately
touching AB and DF, the redundancy in AB may be
exhaufted, and the deficiency in DF fupplied.
But the equilibrium that is thus gradually produced
may be effe£ted at once. If w7e fuppofe a ilender con¬
ducting canal a b d, brought very near the plates on
the outfide, fo that the end a is near to A, and to D >
the firft effeCt of the vicinity of a to A, will be to
caufe the fluid in 6 to recede a little from tf, by rea-
fon of the repulfion of the redundant fluid in AB.
Thus, redundant matter will be left at a, and this will
ftrongly attraCt redundant fluid from A, and a may
receive a fpark. Should the fluid approach ftill nearer
the furface at A, the correfponding part of DF will be
rendered more attractive, and by the fluid retiring from
<t along a fome of the natural fluid of this canal wall
be pulhed towards d; this increafes the difpofition of
A to part with fluid, and of to receive it, while a is
difpofed to give out and D to receive. Ihus all con¬
tributes to favour the paffage of almolt the whole of th§
redundant fluid in AB to rulh from AB, by A, along
abd into DF.
It is alfo clear that, without the canal ab d, there
is a ftrong tendency of the fluid in AB for the matter
in DF, and that, of courfe, thefe plates will ftrongly at-
traft each other.
The theorems we have now given refpeCling the dif¬
pofition of the eleCfric fluid are the refult of mathema¬
tical reafoning, founded on the hypothetical nature of
the fluid, and its affumed law of aCtion. .. We ftiall con¬
clude this feCfion with relating the refult of M. Cou¬
lomb’s experiments on this fubjeCt, given in the Me¬
moirs of the Academy for 1786 and 1787* M. Cou¬
lomb gives the following general theorem.
In a body of any form, AFB d e, fig. i 14* which
is fuppofed filled wfith fluid whofe particles aCt on each
ments on 0tfier with a force that is inverfely as the Iquare of the
■of^he'^fluid diftance, let there be raifed a perpendicular a ^infinitely
m contaCt. fmall, and let a plane, perpendicular to a b at the point
b, divide the body into two parts *, one dacb, infinite¬
ly fmall, the other b AFB c b, of any determinate di-
menfions. Then the aCfion of the particles compofing
the thin flice, eftimated in the direClion ab, on the
particle b, muft be equal to the aCfion of the whole
fluid in the reft of the body, if b be fuppofed at reft.
Now, as whatever be the difpofition of the fluid, the
law of continuity will be the fame, it is evident that
if we take a b fufficiently fmall, the difference of the
denfity at a and at c may be infinitely fmall j and that
U I e I T Y. . . 76S
the aClion of dcbe will be infinitely near to an equitibri- Theory of
um with that oi da eb. Hence the aClion of the fluid in Ele nclty.
the reft of the body wall be reduced to nothing, or will
be infinitely fmall. But this cannot take place when
the aCtion of the mafs at a finite diftance on a particle
of fluid, is infinitely fmall with refpeCt to that of a par¬
ticle in contaCt on the fame particle, unlefs we fuppofe
the quantity of fluid at a finite diftance nearly nothing.
It follows that the whole redundant fluid muft be con-
ftipated on the furface, and the interior parts be merely
faturated.
M. Coulomb then proceeds to examine the denfity of
the eleCtric fluid in different bodies that are in contaCt.
He firft examines the denfity of two globes of dif¬
ferent diameters in contaCt.
After a number qf experiments, he gives the refult
in the following table, reprefenting the manner in
which the fluid is diftributed between the two globes.
The firft column ftiews the proportion of the radii of
the globes, the fecond the proportion of their furfaces,
and the third the correfponding proportion of their den-
fities. It muft be remarked that this table fliews only
the proportional denfity of the globes, when after be¬
ing feparated, the fluid is uniformly diffufed over their-
furfaces.
397
Coulomb’s
experi¬
ments on
I-
%
4-
8
infinite
4
16
. 64
infinite
I
1,08
i,3°
2,00
Thus it appears, that the greater the proportion of the
furfaces of the globes, the nearer the proportion of their
denfities approached to 2, but never attained this.
This is very different from the proportions between
two fpheres that communicate by a very long flender
canal, which, as was ftiewn in N° 390, contained quan,
tkies of fluid proportional to their diameters, and that
the denfities were inverfely as the diameters; and this
M. Coulomb found to agree very exa&ly with experi¬
ment.
M. Coulomb nexts proceeds to examine the denfity
of the fluid in various parts of the furface of the globes
in contaCt, in order to afcertain the diftribution.
His method of proceeding was this. He hung a
fmall circle of gilt paper to a thread of lac, fixed to a
cylinder of glafs or baked wood; the paper was varnifh-
ed with fome eleCtric fubftance. The body to be ex¬
amined was firft touched with the paper circle, the .
eleCtricity of which was then examined by means of his
eleCtrometer, and an eftimation of the denfity of the
fpheres made on the fuppofition that the circle brought.
off one half of the eleCtricity of the touched point.
The refult of numerous experiments made with two 7
globes in contaCt was as follows. The more unequal1
the globes were, the more the denfity of the fmall globe
varied from the point of contaCt to the diftance of 18o°, ,
and the nearer it approached to uniformity in the large
globe, increafing rapidly from the point of contaCt, ,
where it was o, to 70 or 8° from that point.. Thus,
when he placed a fphere of 8 inches in contaCt with
one of two inches, he found the denfity of the fmall
globe infenfible till about 30° from the point of con¬
taCt ; that at 450 it was nearly the one-fourth of what
it was at 90°, and hence it increafed in the proportion
of:
;66
elec
_ ^ ^ rp
EleAricitf. t0, Vf tl!I ’ where it was uniform. In the
'-V— ZT t 0thCT.1’-d, the denfity was o ,U1
to“ to .8o4; enCeI,‘ m-rafed raPit11)'' mi f™®
30 to Ibo 1l was nearly uniform.
^efe r^ults we may conclude that Mr Caven-
h s mathematical demonftration of the uniform dif-
wthZrh k’' omd,in 3 gI°b.e that communicates
£a^ ‘ £r a ^eni^er canal, is conformable to the
A imall globe between two equal larger globes was
found to pofTefs the fame eleftricity as fhe other’two
•when the proportion of their radii was not more than
no eu4rid£n “ WaS Srea,er’ the fma11 SIobe fl‘-ed
I hree equal globes being placed in contaft, the den-
‘fity m the middle one was —L. of that in the other
taft* w-hhM 3 fma11 Sl0lbe, after Having been in con-
tadt with a larger one that was overcharged, was re-
^oved toa veryfman dirtance, the eledricity of the
hnall globe in the fronting point was oppofite to that
ftheiargeone at a little greater diftance the fmall
gJobe was neutra!, and Hill farther off, it was redundant.
ref^Jr Vhe ldlTe1;<;rS °f the globeS Were 11 and 8
refpechvely the fmall globe at the fronting point was
.eganve ,‘11 it was at the diftance ,, when ft was nfu
tral, and beyond this it was pofitive. When the diame¬
ers were 11 and 4, the neutral diilance was 2, and when
they were 11 and 2, the diftance at which the fmall
globe wras neutral was 2\.
ft is indifferent whether the globes be folid, or con-
fift merdy of a thin ftiell. This circumftance is an ad¬
ditional proof of the juftnefs of the theoretical invefti-
gation on the fuppofition of the fluid being diffufed
over the furface, leaving the interior parts i/a neutral
S^T* lb,fn ^PPIica^n of the Theory of TEpinus and
Cavcndijh to the principal Phenomena of EleBricity.
5PS On an attentive confideration of the phenomena
r ,at lave .alread7 paffed under our review, and a care¬
ful companion of thefe with the theory of pofitive and
negative dearicity, as improved by Afpinus and Ca-
vendiJh, it wall, w^e think, appear, that this theory is
adequate to the explanation of the fafts.
I he companfon of the theory with the experiments
may readily be made, and we have already hinted at
it in feveral cafes. We cannot, however, purfue this
to any extent, and muft reftrift ourfelves in the remain-
. er ot.thls c,laPte1' to the more important and intereft-
mg phenomena, leaving the reft to be fupplied by the
reader, for which purpofe we have furniflied him with
/ample materials.
Vv e have already, in our illuftration of the theory of
Aipinus, fo fully confidered the phenomena of eledfric
attraction and repulfion in a general view, that little
more needs to be done, than to explain a few of the
more remarkable cafes.
The phenomena of attraaion and repulfion may be
399 feduced to the following fimple propofitions
Eledtricity Prop. I.—If any body be eleftrificd by any means
lHr iSa f Tf! bAdy be b.r°l'Sht ft, this latte/ b l
iea' coiftcg eleflrifie d by pofition.
^ I C I T Y. part jy
4T:e“em.ate th:s pr0r0fi,i0n % ^ foUoiving^Sj„f'
Let there be provided three metallic condudors,
each iupported on an infulatmg Hand, fuch as A, B, C,
g- 1 if. Set thefe in a row, with their extremities
ouching each other, and at one end of the row, as at c
S6 rn T1’ Which is hunS a bal1 eledrometer
near / i threadr* 0? bnngmg an excited eledric
near the-oppofite end of the condudor, the pith ball
will approach the end c. Care muft, however, be
theTanl't T8 tbe5learic fo near asto make
the ball ftnke the oppofite extremity j as in that cafe
the experiment would come under our fecond propo¬
rtion. W hen the excited eledric is removed, the ball
retires to its perpendicular fituation. The fame effeA
wfl! be produced if the elearometer be placed at
clea °f-the 1?0ndua°rj iniiead of extremity,
not [l7 T1! ^ f 18 affeaed ^the COaduaor, and
n°t nnmethatdy by the exerted eledric.
This is an mftance of induced eledricity, and is eafily
explained on the principles mentioned in N# 344. The
approach of the excited electric to the end a of the
compound condudor, renders this end deficient, if the
electnc be overcharged, or redundant if it be under¬
charged j and the oppofite extremity is in the contrary
ftate and hence attrads the ball of the eledrometer.
Although the oppofite extremities of the condudor
arc m oppofite ftates, the fluid is varioufly difpofed in
vanous parts of the condudor; as may be proved in
the following manner. WTile the excited eledric re¬
mains near 17, take away the two extreme condudors,
A and L, or, if only two have been employed, take
away the remote one ; remove the excited eledric, and
examine the parts of the condudor feparately. The
part A will be found entirely negative ; if the eledric
were overcharged, C will be entirely pofitive : and if
fhiee pieces have been employed, the middle piece B
will be faintly pofitive. If the pieces be again united,
they wall be found devoid of eledricity. The fame ap -
pearances will be more completely feen by forming a
condudor of a feries of metallic balls, lufpended^by
mk threads, one of which wall be found fcarcely eledri-
PRop. II.—When an infulated body is brought very 400
near an eledrified body, a fpark paffes between them,
and the iniulated body becomes eledrified permanently
by communication, while the eledricity of the eledrified
body is diminilhed.
_ In this cafe the eledricity imparted is of the fame
und as that of the eledrified body, pofitive if this were
pofitive, and vice verfa. The propofition may be il-
iullratetl by the fame apparatus of the condudors and
eledrometers, and fcarcely requires an explanation.
. V\hen tbe eledrigity is in a fmall degree, the fpark
:s eitner very fmall or fcarcely perceptible, but ther^ is
no doubt, that it takes place in all cafes. The fpark
is owing to the hidden transference of a portion of the
fluid from the eledrified body to the uneledrified body.
^ Prop. III.—When an eledrified body has com-Repulfiou
municated part of its eledricity to another body, this bodies in
latter is repelled, unlefs it has communicated its acquiredthe fame
ft ore to other bodies. fta;e-
The flying feather, the cork balls, and many other
experiments related in the firft chapter of Part III.
amply
4
Chap. II. ELECT
Theory of amply nluflrate this propofition, which exprefies one
L!ednc:ty.0f t]ie mofl general fa^s in eleftricity.
Before the ele&rified body has communicated part
of its eleflricity t© the body prefented to it, this latter
is in its natural ftate 5 but after the communication,
both are either redundant or deficient, and confequent-
ly repel each other, as appears from N° 323, 324.
From theie general proportions we may deduce the
following corollaries, an application of which will ferve
ftill further to illuftrate and explain the phenomena of
electric attraction and repulfion.
402 Cor. i.- 1 he vivacity of the appearances produced
by a transference of fluid will be proportional to the
quantity of fluid transferred.
4°3 . 2-—phenomena of communicated eleftri-
pity will be more remarkable, the greater the condufl-
ing power of the bodies to which it is communicated.
It will have appeared from numerous experiments re-
lated in I art III. efpecially that of the dancing balls in
N ’94. that an imperfea conductor, fuch as glafs, permits
the communication of eleftricity only in the point pre¬
fented to an eleftrified body j whereas, when eleftricity
is communicated to one point of a tolerably perfedl
conductor, fuch as the prime conductor of a machine,
the whole conduftor is inftantly pervaded, and becomes
electrical in every part.
404 Cor. 3.—When an electrified body has a free com¬
munication with a perfect conduftor, its elearicity can¬
not apparently be communicated to a body touched by
For the mafs of the earth, with which the body com¬
municates, bears fo great a proportion to the body it-
felf, that when the elearicity of the latter is communi¬
cated to the former, it becomes imperceptible in both.
4°5 C°R* 4.—When an unekarified body is prefented
to an elearified body, the former is firft attraaed,
comes in contaa with the elearified body, and is then-
repelled.
I his corollary has been illuftrat’ed by numerous ex¬
periments j we may inflance the dancing figures, &c.
and the appearances are eafily explained. The unelec¬
trified body becomes elearical by induaion 5 in confe-
quence of this, it is attrafled to the elearified body,
from which it receives a fpark, becomes elearified by
communication, and being now in the fame flate with
the elearified body, is repelled by it.
It will probably have been obferved, in making the
experiment of prefenting a feather, or a pith ball, fuf-
pended by a firing to the prime conduaor, that they
cling to the conduaor, and are not repelled for feme
time. The reafon of this is, that thefe bodies are im-
perfea conduaors, efpecially when very dry, and hence
their furface is not eafily pervaded by the fluid j when
this becomes equally diffufed, they are repelled. The
fame cfrcumflance explains why the balls of the com¬
mon elearometer fometimes adhere together, and them
feparate wdth a jerk.
405 Cor. 3,^—Elearical attraaion and repulfion are not
prevented by the interpofition of unele a rifled non-con-
duaing fubftances.
A thin plate of glafs may be interpofed between the
conductor and the pith-ball in the experiment of N°
399, and flill, though the plate be very extenfive, the
elearometer wall be affeaed.
Nay, an infulated elearified body may be covered
ft I C I T Y. 767
with a glafs bell, and it will yet attract a ball prefented Theory of
to it. Electricity.
As this Angle eircumflance affords one of the bell T '
arguments againft the hypethefis of material elearic Hypothefis
atmofpheres, which has been maintained, and is Hill of elearic
maintained, by fome of our moil eminent elearicians ; atrno-
we fhall take this opportunity of giving a brief account
01 this hypothefis, and Hating the reafons tvhich induce
us to rejea it.
It has been fuppofed, that the elearic fluid is collec¬
ted around the lurface of an eleftrified body, forming
a kind of atmofphere } and that on thefe atmofpheres
depended the aaion or thefe elearified bodies. If the
reader will examine the plates of Lord Stanhope’s Prin¬
ciples of Eletiricitg, he will fee the figures of conduc¬
tors furrounded with a fhining margin, like the line of
coafls and illands in a map.
a his idea of elearic atmofpheres was firfi held at a
very early period of the fcience by Otto Guericke, and
afterwards by the academicians del Cimento, wdio con¬
trived to render the elearic atmofphere vifible, by means
of fmoke attraaed by, and uniting itfelf to a piece of am¬
ber, and gently riling from it, and vanifhing as the am¬
ber cooled. But Dr Franklin exhibited this elearic
atmofphere with great advantage, by dropping rofin
on hot iron plates held under bodies ele id rifled, from
which the fmoke rofe and encompaffed the bodies, giv¬
ing them a very beautiful appearance. He made other
obfervations on thofe atmofpheres : he took notice that
they and the air did not feem to exclude one another j
that they were immoveably retained by the bodies from
which they iffued j and that the fame body, in different
circumllances of dilatation and contraflion, is capable of-
receiving and retaining more or lefs of the eleflric fluid
'on its furface. However, the theory of eleffrical at¬
mofpheres was not fufficiently explained and underflood
for a conliderable time 5 and the invefligation led to
many very curious experiments and obfervations. Mr
Canton took the lead, and was followed by Dr Frank¬
lin. Meflrs Wilcke and Axpinus profecuted the in-
quiiy, and completed the dilcovery. The experiments
of the two former gentlemen prepared the way for the
conclnfion that was afterwards drawn from them by the
latter, though they retained the common opinion of
eleftric atmofpheres, and endeavoured to explain the
phenomena by it. The conclufion was, that the eleCtric
fluid, when there is a redundancy of it in any body, re¬
pels the eleCtric fluid in any other body, when they are
brought within the fphere of each others influence, and
diives it into the remote parts of the body, or quite out
of it, if there be any outlet for that purpofe.
By atmofphere M. YEpinus fays, no more is to be un¬
derflood than the fphere of adlion belonging to any bo¬
dyor the neighbouring air eleflrified by it. Sig. Bec-
caria concurs in the fame opinion, that the ele&rified
bodies have no other atmofphere than the eledlricity
communicated to the neighbouring air, and not rvithr
tne electrified bodies. And Mr Canton likewife, hav¬
ing relinquilhed the opinion that eleflrical atmofpheres
\vere compofed of effluvia from excited or eleftrified bo¬
dies, maintained that they only refult from an alteration
in the ftate of the eledlric fluid contained in, or belong¬
ing to the air furrounding thefe bodies to a certain dif-
tance ;. for inflance, that excited glafs repels the elec¬
tric fluid from it, and confequently beyond that diftance
makes
768
Theory of makes it more denfe j whereas excited wax attra&s the
Elearicity.deftric fluid
exifting in the air hearer to it, making it
rarer than it was before.
Among the fupporters of this dodtrine is Dr Peart of
Gainfborough, w'ho has diftinguiihed himfelf as a zeal¬
ous opponent of the chemical theory of LaVoifier, the
fallacy of wThich he has, in his own opinion, fully de-
monilrated. Bur Dr Peart’s atmofphetes are not thofe
of moll eledlricians ; they confift of chemical elements,
of ether and phlogi/lon, by the union and reciprocal
aftion of which all the phenomena of electricity are
effedfed. We are afraid of doing more than Hating this
leading principle of Dr Peart’s hypotheiis, left we
ftiould fhare the fate of Mr Read, with whoih the Doc¬
tor is very angry for only partially agreeing with
him.
We muft therefore refer fuch of our readers, as with
for more fatisfadlion on this head to the Dodtor’s pam¬
phlets on eleBricitij and mdgnetifni^ and on ele&ric dt-
408 mofphereSi
Refuted# It is perhaps a fofficient refutation of this dodlrine
of material atmofphefes, that eledtrical attradlion and
repulfion may take place, where thefe atmofpheres can¬
not, according to the general opinion, be formed. Thus,
in the inftance given above, it is fcarcely conceivable,
that the excited eledlric on one fide of the glafs pane,
or bell, ftiould fo fpeedily extend its atmofphere to the
other fide of the pane, or, in the cafe of the bell, that
it fliould extend it at all, fo as inftantaneoufly to affedl
an eledlrometer prefented to the other fide# Nay, it is
well known, that an eledlrified body will affedl a con-
dudling wire, fo as to render it pofitive at one end, and
negative at the other, though the wire be completely
enveloped in fealing-wax, or fome other eledlric fub-
ftance. It therefore becomes a queftion, how, if the
tnterpofed body be impermeable to the eledlric fluid,
(and we fee no reafon to think that glafs and other per-
fedl eledlrics are not fo), the eledlric atmofphere can
be produced ? The one atmofphere can, in this inftance,
produce the other only by adling at a diftance on the
particles of which this latter is to be formed# Even
fuppofing that the one atmofphere could produce the
other in this way, we ftiould gain nothing by the fup-
pofition. It only fuppofes Innumerable attradtions and
repulfions in place of one.
Dr Franklin whirled an eledlrified ball, fufpended
by a filk thread, many times about his head with great
rapidity, and found that its eledlricity was not fenfibly
diminiflied by the motion. Now it is fcarcely conceiv¬
able, that the eledlric atmofphere could remain attach¬
ed to the ball under thefe circumftances, or that it could
be fo inftantaneoufly formed, of renewed in every point
of its revolution, as to be capable of adlirtg the moment
the motions wTere ended j for the eledlricity of the ball
muft in this wray have been greatly leffened, or nearly
exhaufted ; whereas Dr Franklin found that, when the
air wras very dry, the eledlricity of the revolving ball
was, when the ball was flopped, not lefs than that of a
fimilar ball that had remained for the fame time in a
40p ftate of reft.
Permeabili- We have faid that we fee no reafon to think, that
ty of glafs glafs is permeable to the eledlric fluid. We are aware,
fuppofed by tiiat permeability is fupported by fome eledlricians,
iwme‘ and that experiments have been related in proof of their
opinion. Among the moft plaufible of thefe, are the
Part IV.
experiments of Mr Lyons of Dover, which may all be Theory of
reduced to the following. A wire is brought from the Elea:r'city:
outfide of a phial charged by the knob, and terminates i
in a fharp poin* “t a fmall diftance from a thin glafs
plate \ it is commonly introduced into a glafs tube,
having a ball at the end, and the point of the wire
reaches to the centre of the ball) and another wire
is connedled with the difeharging rod, and alfo comes
very near, and frequently clofe to the other end of
the glafs, oppofite to the pointed wire# With this ap¬
paratus he obtains a difeharge, and therefore fays that
the glafs is permeable to the eleftric fluid#
Dr Robifon repeated moft of Mr Lyons’s experiments,
and found that, in the above way, he did indeed pro¬
cure difeharges, but that thefe were very incomplete,
and very unlike the full and audible difeharge ufually
obtained j they were always very faint, except when the
glafs wras perforated. 410
To terminate this long digreflion, it muft be remark- Eledlrics
ed, that the impermeability of ele&rics fuppofed in our only fo fa-
theory, ftiews that the redundancy or deficiency indu- perflciaUjr#
ced in an overcharged or undercharged eleclric, does
not extend beyond the furface j for, when the furface is
rendered eledtrical by excitation in any vray, the im¬
permeability of the body prevents the redundant fluid
from penetrating to any depth, or from expanding to
fupply the deficiency on the furface. Hence we find,
that an excited eledlric, when plunged into water,
quickly lofes its eleflricity by communication with this
conducing medium.
We muft now return to our corollaries, of which we
lhall deduce one mote# 411
Cor. 6.—As non-ele£lrics are condu£lors, and as Gimpen-
forne eledlrics are excited by rubbing them with non- eke-
eledlrics, it will follow, that if the non-eledlrics be in- tncit?-
fulated and feparated from the eledlric, the former will
flidw figns of eledlricity as well as the latter, but that,
while they remain together, no figns of eledlricity can
be exhibited by either.
This corollary may be illuftrated by numerous fadls
that have been related in the preceding parts of this ar¬
ticle.
The flieets of paper in N° 19. fiiowed no figns of
eledlricity while in contadl with the table } the fulphur
in the experiments of Wilcke and ALpinus, wras not
eledlrical while within the metallic Cups, &c#
When cafes of this kind occur, in which twro bodies,
that would, when feparated after mutual contadl, fhow
figns of oppofite eledlricities, are, wThen united, faid to
coinpenfate each other, the circumfiance is eafily ex¬
plained.
In whatever way excitation is produced by friftion
or other means, winch wTe do not pretend to explain, it
muft happen that the adjoining furfaces of two bodies
rubbed together, muft be irt oppofite ftates, and the
one overcharged in the fame degree as the other is un¬
dercharged. When the bodies, which we ftiall fuppofe
to be two plates, are joined, fo that the one exad^ly co¬
vers the other, they muft be inadlive \ becaufe a par¬
ticle of moveable fluid in any part of one furface of the
overcharged plate, will be as much attradled by the un¬
dercharged furface of the farther plate, as it is repelled
by the overcharged furface of the nearer plate. As the
furfaces are fuppofed equal, coincident, and equally
eledtrical, their adlions muft balance each other. The
adtioii
ELECTRlClTf.
Chap.
412
Elethrical
xvell ex¬
plained.
II. ' E L E C T R
Theory of a&ion of tlie united bodies will be exprefled by FW x
Eledricity. ^—<2') or Wm'; $5—%' being hcire =ro.
]3ut now again, if the plates be feparated, a confider-
able part of the redundant fluid will fly back from the
one furfece to the other, being impelled thither by the
repulfion of its own particles, and drawn by the attrac¬
tion of the redundant matter in the other furface. But,
as the ele£lric is a non-condu£lor, it will retain a por¬
tion of fluid, or will remain deprived of a portion, in a
ftratum a little way within the furface, the two plates
mull, after feparation, be in oppoflte Hates, and the non-
eledric plate, if it has been infulated before feparation,
will, after feparation, appear ele61 rifled.
We (hall clofe our confideration of eledfrical attrac¬
tion and repulflon, by explaining two very beautiful ex •
periments of Dr Franklin j one of which, the eledlrical
well, has been defcribed in N° 79 5 the other lhall be
defcribed prefently.
It appears from Mr Cavendifli’s account of the dif-
pofition of fluid in a fphere, given in N° 372, that
when the fphere is overcharged, all the redundant fluid
is crowded into the furface, leaving the internal parts in
a neutral Hate. Now the veffel that reprefents the elec¬
trical well is exadlly in this condition 5 the electro¬
meter, therefore, when let down within the cavity of
the veffel, cannot be affe£ted, becaufe all that fpace is
neutral •, but when the balls are raifed above the
brim of the veffel, they are affedled, becaufe they
come within the fphere of action of the redundant fur¬
face.
The other experiment to which we allude, is that of
the eledtrified can and chain, which is thus made.
Infulate a metallic can, or any other concave piece
of metal, and place within it a pretty long metallic
chain, having a filk thread tied to one of its ends. At
the handle of the can, or to a wire proceeding from it,
fufpend a cork ball electrometer ; then eleCtrify the can,
by giving it a fpark with the knob of a charged phial,
and the balls of the eleCtrometer will immediately diverge.
If, in this fituation, one end of the chain be gradually
raifed up above the top of the can, by the filk thread,
while the lower end of the chain remains in it, the balls
of the eleCtrometer will converge a little, and more or
lefs in proportion to the greater or lefs elevation of the
chain above the top of the veffel. A fimilar experi¬
ment was made by Mr Ronayne, which is as fol¬
lows :—He excited a long flip of white flannel, or a filk
ribband, by rubbing it with his fingers 5 then, by ap¬
plying his hand to it, took off as many fparks as the ex¬
cited eleCtric would give j but when the flannel, &c.
had loft the power of giving any more fparks in this
manner, he doubled, or rolled it up ; by which operation
the contra6fed flannel, &c. appeared fo ftrongly elec¬
trical, that it not only afforded fparks to the hand,
brought near, but it threw out fpontaneous bruflies of
light, which appeared very beautiful in the dark.
To explain this experiment, wre muft have recourfe to
an inference, that is eafily deducible from the fame
theorem of Mr Cavendilh : namely that in overcharged
bodies of all ftiapes, the redundant fluid will be much
more denfe near the furface than in the more internal
parts •, and that it will be alfo denfer in all elevated or
protuberant parts of thefe bodies, as alfo near the ex¬
tremity of oblong bodies j and in general, that the re¬
dundant fluid, or redundaut matter, will bear a much
Vol- VII. Part II.
413 ,
Electrified
can and
chain.
I 6 I T Y. 769
nearer proportion to the furfaces of bodies^ than to their Theory of
quantities of matter. Hence we may perceive, that hi.ectiicit, ■
when the chain, in the above experiment, is lifted up,
it will attrad to itfelf a part of the denfer fluid, leav¬
ing that of the furface of the veffel, to which the elec¬
trometer is attached, more rare ; and confequently, the
divergence of the balls will decreafe, in proportion
as the chain is more elevated above the rim of the cup.
Mr Ronayne’s experiment admits of a fimilar explana¬
tion.
4r4
The well known effeCts of points, in caufing a quick Aftion of
difcharne of eleCtricity, feem to agree very well withp°’nts ex-
this theory. . ..
It appears from 391, that, if two fimilar bodies of
different fizes are placed at a very great diflance from,
each other, and connected by a llender canal, and over¬
charged, the force with which a particle of fluid placed
clofe to correfponding parts of their furface is repelled
from them, is inverfely as the correfponding diameters
of the bodies. If the diftance of the bodies is final),
there is not fo much difference in the force with which
the particle is repelled by the two bodies ; but ftill, if
the diameters of the two bodies are very different, the
particle will be repelled with much more force from the
fmaller body than from the larger. It is indeed true,
that a particle placed at a certain diftance from the
fmaller body, will be repelled with lefs force, than if it
be placed at the fame diftance from the greater body ;
but this diftance is in moft cafes pretty confiderable. If
the bodies are fpherical, and the repulfion inverfely as
the fquare of the diftance, a particle placed at any di¬
ftance from the furface of the fmaller body, lefs than a
mean proportion between the radii of the two bodies,
will be repelled from it with more force than if it
be placed at the fame diftance from the larger
body.
We may probably, therefore, be well affured, that if
two fimilar bodies are connefted together by a {lender
canal, and are overcharged, the fluid muft efcape fafter
from the fmaller body than from an equal furface of the
larger ; but as the furface of the larger body is greateft,
it is not certain wduch body ought to lofe moft eledlri-
city in the fame time 5 and indeed it feems impoffible
to determine pofitively from this theory which ftiould,
as it depends in a great meafure on the manner in
which the air oppofes the entrance of the eledlric
fluid into it. Perhaps, in fome degrees of eledlrJfica-
tion, the fmaller body may lofe moft, and in others
the larger.
Let now ACB (fig. 116.) be a conical point, {land¬
ing on any body DAB, C being the vertex of the
cone 5 and let DAB be overcharged : Mr Cavendifti
fuppofes, that a particle of fluid placed clofe to the fur¬
face of the cone anywhere between b and C, muft be
repelled with at leaft as much, if not more, force, than
it would, if the part A £ B of the cone was taken a-
way, and the part a Cb connected to DAB by a {len¬
der canal; and confequently, from what has been faid
before, it feems reafonable to fuppofe that the w’afte of
eledlricity from the end of the cone muft be very great
in proportion to its furface ; though it does not appear
from this reafoning, w hether the wafte of electricity from
the whole cone fliould be greater or lefs than from a
cylinder of the fame bafe and altitude.
All that has'been here faid relating to the flowing out
5 E of
77^ ELECT
Theory of of electricity from overcharged bodies, holds equally
£ ertncny. true regarci to flowing in of eledlricity into un-
v _ dercharged bodies.
But a clrcumftance which probably contributes as
much as any thing to the quick difeharge of eleftricity
from points, is the Iwift current of air caufed by them,
as taken notice of in N° 80 et.feq. and which is produ¬
ced in this manner.
If a globular body ABD is overcharged, ihe air clofe
to it, all round its furface, is rendered overcharged by
the electric fluid, which flows into it from the body ;
it will therefore be repelled by the body j but as the air
all round the body is repelled with the fame force,
it is in equilibrio, and has no tendency to fly oft’ from
it. If now the conical point ACE be made to ftand
out from the globe, as the fluid will efcape much falter
in proportion to the furface from the end of the point
than from the reft of the body, the air clofe to it will be
much more overcharged than that clofe to the reft of the
body: it will therefore be repelled with much more force ;
and confequently a current of air will flow along the
ftdes of the cone from B towards C j by which means
there is a continual fupply of frelh air, not much over¬
charged, that the eleflricity would have but little dif-
pofition to flow from the point into it.
The fame current of air is produced in a lefs degree,
without the help of the point, if the body, inftead
of being globular, is oblong or flat, or has knobs on
it, or is otherwife formed in fuch a manner as to make
the ele&ricity efcape fatter from fome parts of it than the
reft.
In like manner, if the body ABD be undercharged,
the air adjoining to it will alfo be undercharged, and
will therefore be repelled by it; but as the air clofe to
the end of the point will be more undercharged than
that dole to the reft of the body, it will be repelled
xvith much more force *, which will caufe exactly the
fame current of air, flowing the fame way, as if the
body was overcharged ; and confequently the velocity
with which the electric fluid flows into the body, will
be very much increafed. We believe, indeed, that it
may be laid down as a conftant rule, that the fafter the
cle&ric fluid efcapes from any body when overcharged,
the fafter will it run into that body when under¬
charged.
Points are not the only bodies which caufe a quick
difeharge of ele&ricity; in particular, it efcapes very
fall from the ends of long flender cylinders ; and a fwift
current of air is caufed to flow' from the middle ‘of the
cylinder towards the end : this will eafily appear by
conlidering, that the redundant fluid is colledted in
much greater quantity near the ends of the cylinders
than near the middle. The fame thing may be faid,
but we believe in a lefs degree, of the edges of thin
plates.
What has been juft faid concerning the current of air,
ferves to explain the reafon of the revolving motion of
Dr Hamilton’s and Mr Kinnerfley’s bent pointed wires,
('N° 81.) for the fame repulficn which impels the air
from the thick part of the ware towards the point, tends
to impel the wftre in the contrary diredlion.
It is well known, that if a body B is pofitively elec¬
trified, and another body A, communicating with the
ground, be then brought near it, the eleftric fluid will
R I C I T Y. Part IV.
efcape fafter from B, at that part of it which is turned Theory 0f
toward A, than before. This is plainly conformable
to theory \ for as A is thereby rendered undercharged,—v—^
B will in its tum be made more overcharged, in that
part of it which is turned towards A, than it was be¬
fore. But it is alio wrell known, that the fluid will
efcape faller from B, if A be pointed, than if it be blunt,
though B will be lei's overcharged in this cafe than in
the other j for the broader the furface of A, which is
turned towards B, the more effeift will it have in increaf-
ing the overcharge of B. The caufe of this phenomenon
is as follows.
If A is pointed, and the pointed end turned towards
B, the air clofe to the point will be very much under¬
charged, and therefore will be flrongly repelled by A,
and attracted by B, which will caufe a fwift current of
air to flow from it towards B 5 by which means a con¬
ftant fupply of undercharged air will be brought in con-
tad: with B, which will accelerate the difeharge of
elediicity from it in a very great degree; and more¬
over, the more pointed A is, the fwifter will be this
current. If, on the other hand, that end of A which
is turned towards B is fo blunt, that the eledricity is
not difpofed to run into A fafter than it is to run out of
B, the air adjoining to B may be as much overcharged
as that adjoining to A is undercharged j and, therefore
may, by the joint repulfion of B and attradion of A,
be impelled from Bto A, with as much, or more force,
than the adjoining air to A is impelled in the contrary
diredion ; fo that what little current of air there is, Ynay
flow in the contrary diredion.
We might here give an account of Coulomb’s experi¬
ments on the diflipation of eledricity into the air, and
along imperfed condudors. But wre muft defer this to
the article Electrometer, under which w e lhall de-
feribe the inftrument with which they were made.
We muft now' proceed to the theory of the Leyden phial.
In the 4th, 6th, and 7th chapters of the third part, we 415
have related a confiderable number of experiments, Phenomena
illuftrating the phenomena of charged eledrics. Before charged
wre examine the theory of the Leyden phial, it will,
therefore, be neceffary to confider the phenomena only
in a Ample cafe, and for this purpofe wre lhall give an
experiment, by which the late Dr Robifon ufed to illuf-
trate the theory of charged glafs.
Fig. 117. reprefents the profeffor’s apparatus. G is
the extremity of a prime condudor, on which is fixed a
quadrant eledrometer H. AB reprefents a round plate
of tin-foil, pafted on a plate of glafs, the edges of which
extend beyond the tin-foil about two inches. The plate
of glafs is fixed to a wooden ftand, fo thaftit may be placed
upright, and at any required diftance from the conduc¬
tor. DF is another plate of equal dimenfions with AB,
having a wire EN fixed in its centre, with its extremity
N, terminating in a fmall ball, from which is hung a
common ball eledrometer. The wire alio pafles through
a wooden ball O, wftiich is faftened to the infulating
ftand P. It is neceffary that the glafs plates be very clean
and dry, and a little wTarm.
The condudor G is to be conneded with the plate
AB, by a wire reaching to the centre C. Now move
the eledrical machine flowly, till the index of the qua¬
drant rife to 30° or 40°, and mark the number of turns
required to produce this effed. Take off the eledricity,
and
Chap. II. K L Z C T
Theory of and having removed the conne&mg wire GC, turn the
Ble<fhicity. machine again llowly, till the index be in the. fame
—v  fituation. The difference in the number of turns in this
latter cafe, from the former, will fhew pretty nearly the
expenditure of fluid neceffary to eleftrify only the plate
of tin-foil. This difference will be found very trifling,
when a low degree of eleftricity is employed j and to
this it is neceflary to confine the eleftrification, to pre¬
vent too great a diffipation from the edges of the plate.
Now replace the wire, and caufe the index of the elec¬
trometer to point again at 30° j bring forward the plate
DF, taking care to keep it julf oppofite and parallel to
AB without touching it. No fenfible change will be
produced on the index, till the plate DF come within
four or five inches of AB, and it may even be brought
much nearer, without making the index fink more than
two or three degrees, unlefs a fpark pafs between AB
and DF. Remove DF again to the difiance of two or
three feet, and fallen to the ball N a piece of chain, or
metallic thread, fo that it may lie on the table. Now
raife the eledlrometer again to 30°, and advance DF
gradually towards AB. The index will gradually fall
as DF advances, but will rife again to its former height,
if DF be carried back to its original fituation.
Thefe appearances are eafily explained in the prin¬
ciples laid down in N° 392, 393* For asDF advances
towards AB, the redundant fluid in the latter repels a
part of the fluid in DF towards the remote end of the
wire EN, as is (hewn by the feparation of the balls at
N j hence an accumulation commences in AB, and the
index of the electrometer HG falls juft as if part of the
fluid in the prime conduftor were communicated to
AB. When DF is made to communicate with the
floor, much more electricity is repelled from DF, ac¬
cording as it approaches nearer to AB j but, by reafon
of the communication, the ele&rometer at N gives no
ligns of electricity.
If, inftead of connecting AB with the prime conduc¬
tor, rve adapt to the wire GC, at the extremity G, a
metallic plate of the fame dimenfions as AB, with an
eleCtrometer attached to it next AB, and if this appa¬
ratus be any how eleCtrified, and the feparation of the
balls at H be noted, before DF, which communicates
^vith the floor, be approached, on attending to the
charges, it will be feen, that the divergency of the balls
correfponds very nearly to the diltance of DF, as is re¬
quired by the theory.
Now, while the plates are near each other, efpecially
if DF communicates with the floor, if wre fufpend a
pith ball by a filk thread between AB and DF, the
ball wall be ftrongly attraded by either of thefe plates
that is neareft to it, fuppofe DF $ and, having touch¬
ed this, it will be immediately repelled, and drawn to¬
wards AB, by which it wall be again repelled to DF,
and it will thus be driven backwards and forwards like
the eleCtrified fpider defcribed in N° 1 26, as long as
any eleCtricity remains in either of the plates. In the
mean time, the index of the eleCtrometer at H will
gradually defcend, till the motion of the pith ball
ceafes.
All thefe appearances are more remarkable, ac¬
cording as the plates are nearer to each other, and
when they come in contaCt, the phenomena are the moft
complete.
If, when the plates are charged, we approach one
It I C I T Y. 771
end of a bended wire, (having a downy feather at each Theory of
end, to the plate DF, and bring the other to AB, we^e ^vlt- i
ftiall obferve the feathers fpread out their fibres to the
plates, and then the equilibrium will be reftored, or the
plates will be difeharged.
Having, by means of this experiment, brought again
into view the phenomena of charging and difeharging
a coated eleCtric, we are prepared to explain the theory
of the Leyden phial, which can eafily be done by re¬
curring to the important theorem of the difpolition and
aCtions of four parallel plates, fo fully detailed in
N° 392. - . 416
The following obfervations will alfo afford fome idea Theory of
of the manner in which the fluid is difpofed in the fub-en
ftance of the glafs. _ ^1
It fully appears from what has been faid in N° 409.
that the eleCtric fluid is not able to penetrate a plate
of glafs without breaking it •, and yet it feems able
to penetrate to a very fmall depth, w'e might almoft
fay, an imperceptible depth, within the furface of the
glafs.
Let ACGM, fig. 118. reprefent a flat plate of glafs,
or any other fubftance wftiich will not fuffer the eleCtric
fluid to pafs through it, feen edgeways; and let BbdD%
and E ef¥, or B r/ and E fy as we ftiall call them for
fhortnefs, be tw’O plates of conducting matter of the
fame fize, placed in contaCt with the glafs, oppofite to
each other ; and let B </ be pofitively eleCtrified ; and
let E f communicate with the ground ; and let the fluid
be fuppofed either able to enter a little w\ay into the
glafs, but not to pafs through it, or unable to enter it
at all; and if it is able to enter a little way into it, let
B $ r/, or £ 2 as we ftiall call it, reprefent that part of
the glafs, into which the fluid can enter from the plate
B b, and e <p that which the fluid from E/can enter.
By the above mentioned propofition, N° 134* ^ aP~
pears that if b e, the thicknefs of the glafs, is very fmall
in refpeCt of b d, the diameter of the plates, the quan¬
tity of redundant fluid forced into the fpace B or B q
(that is, into the plate B d, if the fluid is unable to
penetrate at all into the glafs, or into the plate B d,
and the fpace b $, together if the fluid is able to pene¬
trate into the glafs) will be many times greater than
what would be forced into it by the fame degree of
electrification, if it had been placed by itfelf; and the
quantity of fluid driven out of E <p will be nearly equal
to the redundant fluid in B $.
If a communication be now made between B S and
E p by the canal NRS, the redundant fluid will run
from B S to E <p; and if in its way it paffes through the
body of any animal, it will, by the rapidity of its mo¬
tion produce in it that fenfation, called a Jhock.
It appears from N° 392, that, if a body of any fize
was eleCtrified in the fame degree as the plate B d, and
a communication wras made between that body and the
ground, by a canal of the fame length, breadth, and
thicknefs as NRS ; that then the fluid in that canal
would be impelled with the fame force as that in NRS,
fuppofing the fluid in both canals to be incompref-
fible ; and confequently, as the quantity of fluid to be
moved, and the refiftance to its motion, is the fame in
both canals, the fluid ftiould move with the fame rapi¬
dity in both : and there feems no reafon to think that
the cafe will be different, if the communication is made
by canals of real fluid.
Therefore
772
ELECTRICITY. Part IV.
Theory of Therefore, in the opinion of Mr Cavendiih, as great
Eleiflricity. a Would be produced by making a communica¬
tion between the condudlor and the ground, as between
the two fides of the Leyden phial, by canals of the
fame length, and fame kind. This feems a neceffary
confequence of this theory j as the quantity of fluid which
pafles through the canal is, by the fuppofition, the fame
in both 5 and there is the greatefl: reafon to think, that
the rapidity with which it pafles, will be nearly, if not
quite, the fame in both.
It may be worth obferving, that the longer the ca¬
nal NRS is, by which the communication is made, the
lefs will be the rapidity with which the fluid moves
along it ; for the longer the canal is, the greater is the
refiftance to the motion of the fluid in it ; whereas the
force with which the whole quantity of fluid in it is im¬
pelled, is the fame whatever be the length of the canal.
Accordingly it is found in melting fmall wires, by di-
redling a fliock through them, that the longer the wire,
the greater charge it requires to melt it.
As the fluid in B S, is attradled with great force by
the redundant matter in E <p, it is plain that if the fluid
is able to penetrate at all into the glafs, great part of
the redundant fluid will be lodged in b d, and in like
manner there will be a great deficiency of fluid in e (p.
But in order to form fome eftimate of the proportion of
the redundant fluid, which will be lodged in £ § : let
the communication between E /' and the ground be
taken away, as well as that by which B is eledtrified;
and let fo much fluid be taken from B as to make
the redundant fluid therein equal to the deficient fluid
in E cp. If we fuppofe that all the redundant fluid is
colleiled in b S, and all the deficient in E <p, fo as to
leave B d and E f faturated ; then as the ele&ric repul-
fion is inverfely as the fquare of the diftance, a particle
of fluid placed anywhere in the plane b d, except near
the extremities b and d, will be attracted with very
near as much force by the redundant matter in e <p, as
it is repelled by the redundant fluid in b 5. Hence it
follows, that if the depth to which the fluid can pene¬
trate is very fmall in refpedl of the thicknefs of the
glafs, but yet is fuch that the quantity of fluid
naturally contained in £ S or c <p, is confiderably
more than the redundant fluid in B ^; then, as the re-
pulfion is inverfely as the fquare of the diftance, almoft
all the redundant fluid will be colledled in b S, leaving
the plate B d not very much overcharged ; and in like
manner E f will be not very much undercharged : if the
repulfion were inverfely as fome higher power than the
fquare, B d wall be very much overcharged, and E f
very much undercharged : and if the repulfion were in¬
verfely as fome lower powyer than the fquare, B d will be
very much undercharged, and E/Very much overcharged.
4X7 It is a part of Dr Franklin’s theory, that no ele<ftric
fluid can be thrown into one fide of a coated plate, un-
lefs an equal quantity be at the fame time abftradled
from the other fide j and that confequently the charged
plate contains no more fluid than before it was char¬
ged. We find, indeed, that one fide of the plate will
not receive a charge, unlefs the other fide at the fame
time communicate with the ground. He infers the
fame confequence from the circumftance, that if ajar
be difcharged through a perfon when infulated, the per-
fon is not found elesftrified ; the neceflary confequence
of which is, according to Dr Franklin, that any nutn>
ber of jars may be charged by the fame turns of a ma- Theory of
chine, provided that the cutfide of one ]ar communi- Ele<ftricity,
cates with the infide of the next fucceflively, while the
outlide of the laft has a communication with the ground.
He found, however, by experiment, that a greater
number of turns was neceflary, than his theory requir¬
ed ; but he attributed this circumftance to the diffipa-
tion of the fluid into the air. But we learn from our
theory that the redundant matter in the plate that com¬
municates with the ground is lefs than the redundant
fluid in the other plate in the proportion of n—i to n :
and that the proportion of redundant fluidin the next plate
or jar is no greater. If we have any number of jars,
m
the charge of the rath jar in the feries, will be - -
m
If the charge of the firft jar or nr=z6o, that of the loth
will= 51 nearly.
Though a coated plate wall not receive a charge, un¬
lefs one fide communicate with the ground, it may how¬
ever be rendered electrical, as appears when we attempt
to charge it while infulated. For when we attempt to
eleCtrify one fide, the other gives a fpark which proves
this to be eleCtrified alfo. Again, when a charged
phial is difcharged by means of an infulated difcharger,
it always remains eleCtrical, pofitively or negatively,
according as the body from wThich it wTas charged was
pofitive or negative.
It was fuppofed by Wilcke, that when a jar is char- Miftake of
ged by connecting one fide of it with the prime con-Wilcke.
duCtor, and the other with the rubber, it is neutral on
both fides. But if this were the cafe, it could not be
difcharged ; and in faCt, it will be found by experiment
to be equally aCtive on both fides.
It is fcarcely neceflary to remark, that the theory of Method of
the Leyden phial, and that of a coated plate, are the verifying
fame ; and hence we have an eafy method of compar- t^ie flieory-
ing the theory with experiment, by taking two plates
of the fame kind of glafs, and of an equal thicknefs,
but different in the extent of coated furface. If we-
charge both plates, by means of very long conducting
wires attached to both fides, we are to meafure how
often the charge of the leffer plate is contained in the
greater, which is eafily done by the following method
of Mr Cavendifh.
420
When a jar is charged, obferve the eleCtrometer that Cavemlilh’s
is connected with it, and immediately communicate method of
the charge to another equal jar, the perfeCt equality of me^urinS
which has been previoufly afcertained by the methods, c a S •
which will prefently appear. Again, note the elec¬
trometer. This will give the elevation, that indicates
one half, independent of all theory. Now eleCtrify a
jar, or a feries of equal jars, to the fame degree as the
firft, and communicate the charge to a coated plate of
mirror glafs, difcharging the plate after each communi¬
cation, till the eleCtrometer reaches the degree that in¬
dicates one half. This fhews how often the charge
of the plate is contained in that of the jar or row of
jars.
Let the charge of the plate be to that of the jars as
# to 1. Then by each communication, the eleCtricity is'
diminhhed in the proportion of 1 -J-* to 1. li m com¬
munications have been made, it will be reduced in the
proportion of \-\-xm to 1. Therefore 1 and
1 -\-x—mV2, and xz=.mV2—1.
When
Chap. II. ELECT
Theorv of When * is fmall in proportion to I, we fhall come
Electricity. very near the truth, by multiplying the number ot
'     communications by 1,444, ^trading 0,5 from the pro¬
duct The remainder (hews how olten the charge oi
the plate is contained in that of the jars 01 —.
The important difcovery of Franklin, that the charge
of coated glafs refides in the glafs, and not 111 the coat¬
ing, led Beccaria to a no lets important dilcoycr} ;
namely, that in a charged plate of glafs, and probably
of any other eleAric, there are feveral ftrata, incon¬
ceivably thin, that are alternately in a pofitive and ne¬
gative date, and that the number of thefe ftrata m-
creafes as the electrification is continued. .
This difpofition of the furfaces of eleCtric plates ex¬
plains many phenomena •, particularly the experiments
with charged plates defcribed m N° 151. and fonie cu¬
rious appearances obferved by Beccaria, and ranked by
him under the head of vindicating electricity.
They are thus defcribed by Mr Cavallo.
422. , 1. AB, ab, fig. HQ, reprefents a plate ot glais,
vindTcaunP-coated on both fides with the two metallic coatings,
eletricity2 CD, c *, which are not ftuck to the plate, but only
laid upon it. , ,
From the upper coating CD, three filk threads pro¬
ceed, which are united at their top H, by which the
faid coating may be removed from the plate in an imu-
lated manner, and may be prefented to an electrified
electrometer as reprefented in fig. 120. m order to ex¬
amine its eleCtricity. fG is a glafs ftand, which in u-
lates and fupports the plate, &c.
2. Let the plate AB, a b, be charged m the com¬
mon manner, by means of an eleCtrical machine,, lo
that its furface AB may acquire one kind of eleCtncity,
(which may'be called K) and the oppofite furface
may acquire the contrary eleCtricity, (which we ftiall
call L). Then, if the coating CD be . removed trom
the plate, and be prefented to an eleCtrified electrome¬
ter, as reprefented in fig. 120, it will be found poffel-
fed of the eleCtricity K, viz. of the fame kind with
that which was communicated to the furface AB of the
glafs plate •, from whence it is deduced, that the fuiface
AB has imparted fome of its eleCtricity to the coating.
Now, this difpofition of the charged plate to give part
of its electricity to the coating, is what the learned
F. Beccaria nominates the negative vindicating elec¬
tricity. _ .
3. If the coating be again and again. alternately
laid upon the plate and removed, its eleCtricity K will
be found to decreafe gradually, till after a number of
times (which is greater or lefs, according as the edges
of the plate infulate more or lefs exaCtly), the. coating
will not appear at all eleCtrified. I his ftate is. called
the limit of the two contrary eleCtricities 5 for if now
the above-mentioned operation of coating and uncoat¬
ing the plate be continued, the coating will be found
poffeffed of the contrary eleftricity, viz. the eleCtricity
L. This elearicity, L, of the coating is weak on its
firft appearance j but it gradually grows ftronger and
ftronger till a certain degree •, then infenfibly decreafes,
and continues decreafing until the glafs plate has en¬
tirely loft every fign of elearicity.
By this change of elearicity in the coating, it is de¬
duced, that the furface AB of the glafs plate changes
R 1 C I T Y. 113
property, and whereas at firft it was dj[pofed
with its elearicity, now, (viz. beyond the. limit, ot the ^ 1
two contrary elearicities) it feems to vindicate its own
property, that is, to take from the coating.fome elec¬
tricity of the fame kind with that of which it was
charged : hence this difpofition wTas by F. Beccaria
called the pofitive vindicating electricity.
4. This pofitive vindicating elearicity never changes,
though the coating be touched every time it is re¬
moved. It appears ftronger, and lafts a very confider-
able time after the plate has been difeharged \ wdnch is
a very furprifing property of glafs, and probably of all
good and folid eleancs.
5. If, foon after the difeharge of the plate, the coat¬
ing be alternately taken from the plate, and replaced,
but with the following law,, viz, that when the coating'
is upon the plate, both coatings be touched at the fame
time, and wThen the coating is cut off, this be either
touched or not : then the furface AB of the plate, on
being uncoated every time, takes a quantity of elec¬
tricity, which it alternately lofes every time it is coat-
ed. . . an
6. On removing the coating in a dark room, a flaih
of light appears between it and the glafs, which is ftill
more confpicuous if the coating be removed by the
fingers being applied immediately to it, viz. not in an
infulated manner, becaufe, when the coating is not in-
fulated, the glafs plate can give to, or receive from it,
more of the ele&ric fluid, and that mgre freely, than
otherwife. . .
y. It is obfervable, that in the negative vindicating
eleftricity, the glafs lofes a greater or lefs portion of
electricity in an inverfe proportion of the charge given
to the plate, viz. the part loft is greater when the charge
has been the weaker } for in the pofitive. vindicating
eleCtricity, the force of receiving eleCtricity is the
ftronger, when the charge has been ftronger, and con-
trarywufe. . .
8. If, after every time that the coating CD is re¬
moved, the atmofpheres E, e, that is, the air conti¬
guous to the furface of the glafs plate, be examined,
they will be found ekarified as in the following table,
viz. the threads of an ekarometer, brought within one
or two inches, or more, of the furfaces AB, ab, will
diverge with ekaricities contrary to thofe expreffed ill -
the table.
During the (the air E.
time of the j if the plate
negative vin-qhas been
dicating Elec- I charged
tricity * the air e is electrified L
During the rthe
time of the po- I
fitive vindicat-<
ing Eledtri- I
moderately moderately L
high - - "1 0
very high - moderately K
> are eledtrified L.
city
The
The theory of coated glafs naturally leads us to that 423
of the ekarophorus; for though this apparatus is not
exaaiy fimilar to a charged plate, as has been fuppcr-phoru5
fed by fome •, there is yet a confiderable refemblance
in the phenomena.
We have given a defeription of the ekarophorus,
and of its effeas in Chap. X. of Part III. where we al-
fo ftated, that, for illuftrating the theory, it was prop*r
to
.424 .
Difpofition
of fluid in
425
t. Its pri¬
mitive
ftate.
774 ELECT
mSkitt u n’,?krhr fcve?1 part!.of the apparatus of confidera.
' v ' b e t^cknefs, as the more mftrudhve but minute changes
are thus greatly increafed, though the ihowy and bril-
Jiant phenomena are not fo remarkable. Fig. 121. re-
prefents a fe&ion of the three parts of the apparatus in
contaft, where ABCD is the dearie cake, CDEF the
>/e and ABHG the cover. They are here reprefen-
ted lying horizontally on each other ; but for experi¬
ment, it will be moft convenient to have them fixed
vertically to glafs fupporters, furnilhed with leaden
leet to keep them fteady.
We might here give a mathematical explanation of
the phenomena of the elearophorus 5 and the adions of
every part of the apparatus might eafily be ftated by
means of the propofitions in N° 308 to 314, and the
eorrefponding ones in N° 228-335, taking into con¬
sideration the true law of adion. J5ut as this would
e going over again much of the ground that we have
already trodden, where our readers might not be pleaf-
ed with being obliged to follow us j we fhall treat the
lubject m a manner fomewhat more popular, the refult
however, of If rid mathematical reafoning*.
Having related the general phenomena in N° 207
the eleflro-T • n0W t0 conrider only the difpofition of fluid in
phoms. the. v.anous Parts the apparatus in various fituations,
and the mutual forces that operate between them.
We fhall confider the inlfrument under various dates.
When the cake is left to cool after being made, it
becomes negative by cooling 5 and if it were by itfelf,
t e lurface on both fides rvould be negative to a confi-
derable thicknefs near the edges; and the fluid would
probably grow denfer by degrees towards the middle,
where it would have its natural denfity. This difpofi¬
tion may be inferred from N° 3 71, 3 7 2. But as it cools
in conjundion rvith the foie, the attradion of the re¬
dundant matter in the cake for the moveable fluid in
the foie, muff difturb its uniform diffufion in the foie, and
caufe it to approach the cake. And as this probably
happens while the cake is ftill in a conduding ftate,
the difpofition of its fluid will be different from what is
defenbed above, and the final difpofition of the fluid in
the cake and foie will refemble that given in N° 371.
where the plates may reprefent the cake and foie. It
will be fufficient at prefent to confider the cake and
o e as divided into only two ftrata 5 one containing re¬
dundant fluid, and the other deficient, negleding the
neutral ftratum interpofed between them in each. The
cake then confifts of a ftratum AB b a A, containing
redundant matter, and a ftratum abCD containing re¬
dundant fluid ; and the foie of a ftratum DC n m con¬
taining redundant fluid 5 that is, all that belongs natu¬
rally to. the fpace DC FE, and of a ftratum inn FE,
containing redundant matter. We may call this the
primitive Jlate of the cake and foie j and if this is once
changed by communication with unele&rified bodies, it
can never be recovered wdthout new excitation.
2. If the foie is touched by a body that communi¬
cates with the ground, fluid will enter it, till the repul-
fion of the redundant Jluid in the foie for a fuperficial
particle. is equal to the attraction of the redundant
matter in the cake for the fame particle. What we
have faid concerning infinitely extended plates rendered
neutral on one fide, may fuftice to give a notion of the
.prefent difpofition of the fluid in the foie. The infe-
427
426
2. Common
ttate.
R I C I T Y. part jy
nor lurface will be neutral; and the denfity of the fluid Th,«y of
Will mcreafe towards the furface DC. The foie con- E,e&ricity.
tains more than its natural quantity of fluid, but is neu- ' 
•r 1 by,the hf1.31106 of 0PPofite forces. Let it now be
inlulated. This may be called the common Rate of the
eleerrophorus.
3. Place the cover GHBA on the cake. A particle
r’xfiu U?per furface of the cover> muft be more at¬
tracted by the redundant matter in the ftratum AB b a
than i± will be repelled by the redundant fluid in the
remoter ftrata j for the fluid in the cake is lefs than
when it is in its natural ftate, and therefore Z is at-
racted by the cake. The redundant fluid which has
entered the remote fide of the foie is lefs than what
wouid be fufficient to faturate the redundant matter of
the cake,^ becaufe it only balances the excefs of the re¬
mote a chon of this matter above the nearer a&ion of
the compreffed fluid in the foie, and this fmaller quan¬
tity of redundant fluid ads on Z at a greater diftance
than that of the redundant matter in the cake. There¬
fore the particle Z, lying immediately within the fur-
face GH, is on the whole attra&ed ; fome fluid will
move toward the cake, and its natural ftate of uniform
diffufion in the cover, will be changed into a violent
itate, m which the fluid will be compreffed on the fur-
face AB, and abftradled from the furface GH. There
will now be a ftratum GgpH, containing redundant
?13j,:er> and another gp BA containing redundant
fluid. But this difpofition wall difturb the arrangement
that had taken place in the foie, and had rendered it
neutral on the inferior furface. The particle Z fituated
in that furface, will be more repelled by the compreffed
fluid m the ftratum gp CA than it will be attraded by
the equivalent more remote redundant matter in GH
pg. Fluid is now therefore difpofed to quit the fur¬
face EF, and the foie will appear pofitively ele&ric, but
in a fmall degree only, if the cover be thin. All this
may'be obferved by attaching a fmall ball elearometer
to the low7er furface of the foie, or touching the foie,
with it, and then trying its ekaricity by excited glafs,
or fealing-wax.
4- particle of fluid Z, placed immediately with¬
out the furface GH, is more attraaed by the deficient
ftratum GH g q and by AB b a, than it'is repelled by
the redundant ftrata beyond them, and hence the cover
muft be fenfibly negative. This is the common ftate
of the whole apparatus after fetting on the cover.
The lower furface of the foie is flightly pofitive, and
the upper furface of the cover more lenfibly negative.
A fmart Ipark will be feen between the apparatus and
the finger, and fluid will enter, till the attraaion of
the redundant matter in AB b a balances the repulfion
of the redundant fluid in DC FE.
5. A fpark may.now be obtained from the foie , nei
it. was faintly pofitive before, and there is now the ad-ftate.
ditional aaion of the fluid that has entered into the
cover. Part of the fluid in the foie is therefore difpo¬
fed to fly to any body that is prefented to it. But wrhen
this transference has taken place, the equilibrium at the
furface GH is deftroyed, and this furface again becomes
negative, and will attradf fluid, although the cover con¬
tains already more than its natural quantity. A finall
fpark will therefore be feen between the cover and any
conducing body prefented to it. By touching it, the
neutrality
428
r 4*9
tor Its neutral
Part V. E' L E C T R
Atmo- neutrality or equilibrium may be reftored at GH j but
fpherical it wftl be deftroyed again at EF, from which a pofitive
Elearicitv. fpark may be obtained, leaving GH negative in its
* turn. This would go on for ever, in a feries of com¬
munications continually diminilhing fo as at lalt to be¬
come infenfible, if the three parts of the elettrophorus
be thin. This (hews the necefiity of making them
otherwife, if the initrument be intended for illuilrating
the theory.
The equilibrium is at length completed at the fur-
faces GH and EF, both of which are neutral with re-
fpe£l to furrounding bodies, although both the cover
and foie contain more than their natural (hare of elec¬
tric fluid. This ftate of the apparatus may be called
its neutral Jlate; and it may be produced at once, in-
Head of doing it by thefe alternate touches of GH and
Its charged EF. If we touch at once both thefe furfaces, we lhall
ftate. have a bright, pungent fpark, and a fmall (hock. If
this be the objeft of the experiment, the ftate N° 428.
which gives occafton to it may be called the charged
Jlate of the elecftrophorus.
When the apparatus has been thus rendered neutral
with refpeft to furrounding bodies, it may continue in
this ftate for any length of time, without its eapability
of producing the other phenomena being diminilhed,
provided that no fluid pafs from the cover to the
cake.
6. Now if the cover be removed to a diftance, both
parts of the apparatus will exhibit ftrong marks of elec¬
tricity. For the cover contains much redundant fluid,
and muft therefore appear ftrongly pofitive j it will give
a brilk fpark, which may be employed for any purpofe,
particularly for charging a jar pofltively by the knob,
if we juft touch the cover with the knob. Again, the
foie will attraft fluid, or it will be negative, though it
contains more than its natural quantity of fluid •, it will
therefore take a fpark. The foie, therefore, in the ab-
fence of the cover, may be employed to charge a jar
negatively by the knob. By being touched with the
■finger, or with the knob of a jar held in the hand, it
will be reduced to the common ftate defcribed in
N* 426.; and now all the former experiments may be
repeated. We may call this the aBive or the charging
Jlate of the eleflrophorus.
7. If the ele6trophorus be not infulated, a (hock may,
however, be obtained, by touching firft the foie, and
then the cover, wuthout taking off the finger 5 but will
not be fo fmart as wdien the negative caver is touched
I C I T Y.
at the fame time with the foie.
43*
Its charg¬
ing ftate.
43*
77 z
Atmo-
however, be fcarcely perceptible when the pieces are
The difference will,
433
434
8. If the apparatus has not been infulated, the cover
wdien put on wall afford a fpark, in the manner already
mentioned, and this will be rather ftronger than when
it is infulated j for the fluid being allowed to efcape
from the foie, does not obllrucl the entry of fluid into
the cover. If then, without removing the finger from
the cover, w7e touch the foie, we feel nothing 3 but if
we firrt touch the foie, and then, without removing the
finger from it, touch the cover, we (hall obtain a fhock.
By this feries of alternate touches, the period of the
elehtrophorus is completed. For it is firft charged or
rendered neutral, by touching the plates in contact;
then, by touching both wdien feparate, the whole is re¬
duced to the common ftate. When after having beerk
in the neutral Jlate they are feparated, they have oppo-
fite ele&ricities, the /c/e having that of the cake. When
brought together, each in the common Jlate, they have
oppofite electricities, the cover having that of the
cake.
9. By being long expofed to the air without the Method of
cover, the eleCtrophorus gradually lofes its activity, renewing
This may however be ftgain reftored in feveral ways.lts ac 1VI ^
One of the molt obvious methods is, to produce a frefh
excitation of the refinous cake j and this is belt done by'
rubbing it with a piece of new flannel, of cat or hare’s
Ikin, or, what anfwers ftill better, a piece of mole Ikin j
This friCtion renders the cake negative. It may alfo
be eleCtrified negatively, by placing on it a jar charged
negatively in the infide, and then touching the knob of
the jar with any conducting body that communicates
with the ground. By this means it may be very ftrong¬
ly excited, if the jar be large, and if the cake be cover¬
ed with a piece of tinfoil,* that comes clofely in contaCt
with its whole furface. But one of the moft expedi¬
tious and effectual methods of reftoring the energy of
the cake, will be to eleCtrify it by means of an eleCtri-
cal machine, while the furface of the cake is connect¬
ed with the rubber.
The only important part of the theory of eleCtricity
wdnch wre have yet to confider, is that of the conden-
fer, but as this will be greatly elucidated by an appli-
tion of Coulomb’s experiments on injulators, we lhall
delay it till we give an account of thefe in the article
Electrometer.
PART V.
ON ATMOSPHERICAL ELECTRICITY.
THE phenomena of eleCtricity, that we have hither¬
to defcribed, are fufficiently curious, and many of them
extremely interefting •, but they are trifling, when com¬
pared with thofe that are now to come under our confi-
deration. In the prelent part of our article, we are to
view the eleCtric fluid as one of the principal agents, em¬
ployed to produce fome of the moft remarkable and af-
toni filing phenomena of nature. We are about to
prove, by a feries of the moft fatisfaclory experiments, .
that thunder and lightning are merely the effeCls of a
vaft explofion of accumulated eleftricity in the atmof-
phere.-
Chap*.
E L E C T It
776
Atmo-
fpherical
Eledlricity.
435
Identity of
eledlricity
and light¬
ning.
43s
Conjedlur-
ed by Wall
and Grey.
„ 437
By the ab-
die Nollet.
438 J
Suppofed
by Dr
franklin.
Chap. I. Of Thunder.
SECT. I. Of the Identity of E/e&ricity and Lightning.
It is not furprifing that the experiments in which
the eleftric fpark is made to produce the effefts which
we have recounted in the third part of this article,
fhould have led philofophers to conceive a fimilarity
between thefe effefls, and thofe produced by lightning.
Dr Wall and Mr Grey feem to have fancied a re-
femblance between thunder and the fnapping noife pro¬
duced by applying the fingers to an excited ele&ric :
•but how fuch a refemblance Ihould ftrike them, is not
eafy to conceive; and indeed it feems to have been
merely a bold conje£ture.
The abbe Nollet appears to have formed the firfl: ra¬
tional idea of their fimilitude, and exprefles himfelf on
the fubjeft in the following remarkable manner.
“ If any one Ihould take upon him to prove from a
.well connefled comparifon of phenomena, that thunder
is in the hands of nature what electricity is in ours j
that the wonders which we now exhibit at our pleafure,
are little imitations of thofe great effects that frighten
us, and that the whole depends upon the fame mecha-
nifm : if it can be demonftrated that a cloud prepared
by the aCtion of the winds, by heat, by a mixture of ex¬
halations, &c. is oppofite to a terrellrial objeCl j that
this is the electrified body, and at a certain proximity
to that which is not: I avow that this idea, if it was
well fupported, would give me a great deal of pleafuie ;
and in fupport of it, how many fpecious reafons prefcnt
themfelves to a man who is well acquainted with elec¬
tricity ! The univerfality of the eleCtric matter, the
readinefs of its aCtion, its inflammability, and its adlivity
in giving fire to other bodies, its property of linking
externally and internally even to their fmalleft parts,
the remarkable example we have of this efi’eCl in the
Leyden experiment, the idea which we might truly
adopt in fuppofing a greater degree of eleftric power,
&c. all thefe points of analogy which I have been
fome time meditating, begin to make me believe, that
by taking eledlricity for the model, one might form to
one’s felf, in refpeft to thunder and lightning, more per-
feft and more probable ideas than have hitherto been
offered.”
But the firit electrician who formed a plan for afcer-
taining the truth of this hypothefis, was Dr Franklin,
who truly realized the fable of Prometheus in bringing
down fire from heaven.
Before we relate Dr Franklin’s experiments, we
{hall ftate the points of refemblance which led him to
-think of making them.
He begins his account of the fimilarity of the elec¬
tric fluid and lightning, by cautioning his readers not
to be ftaggered at the great difference of effeCls in
point of degree j fince that was no argument of any
jlifparity in their nature. It is no winder, lays he, if
the effeCls of the one fliould be fo much greater than
thofe of the other. For if two gun-barrels eleftrified
will ftrike at two inches diftance, and make a loud re¬
port ) at howT great a diftance will 10,000 acres of elec¬
trified cloud ftrike and give its fire, and how loud muft
be the crack !
l, Flalhes of lightning, are generally feen crooked
I C I T Y. Part V.
and waving in the air. The fame is the ele&ric fpark Atmo-
always, when it is drawn from an irregular body at jphencal
fome diftance. He might have added, when it is 7 LCt‘ult>‘
drawrn by an irregular body, and through a fpace in
which the beft conductors are difpofed in an irregular Similar ef-
manner, which is always the cafe in the heterogeneous fe&s of
atmofphere of our globe. ' ' a^d^ledtri
2. Lightning ftrikesthe higheft and moft pointed ob-c^. C1
jeCts in its wTay, preferably to others j as high hills and
trees, towers, fpires, mafts of {hips, points of fpears, &c.
In like manner, all pointed conductors receive or throw
off the eleCtric fluid more readily than thofe wdiich are
terminated by flat furfaces.
3. Lightning is obferved to take the readieft and beft
conductor ; fo does eleCtricity in the difcharge of the
Leyden phial.
4. Lightning fets fire to inflammable bodies; fo does
eleCtricity.
5. Lightning, as well as eleCbricity, fufes metals.
6. Lightning rends fome bodies. The fame does
eleCtricity.
7. Lightning has often been knowm to ftrike people
blind. And a pigeon, after a violent ftiock of eleCtri¬
city, by which the DoCtor intended to have killed it,
was obferved to have been (truck blind likewife.
8. Lightning deftroys animal life. Animals have
likewife been killed by the fhock of eleCtricity.
9. Magnets have been obferved to lofe their virtue,
or to have their poles reverfed by lightning. The
fame effeCt has been produced by eleCtricity. 440
Reafoning on the fimilarity of thefe effeCts, he form- Franklin’s
ed the bold attempt to draw down lightning from the ProP°fal for
clouds, and examine by experiment whether he could thef/con-
produce effeCts fimilar to thofe of nature. Having ob-je(qures.
ferved the effeCts of pointed conductors in attracting the
eleCtric fluid more eafily than thofe of any other form,
he conceived that pointed rods of iron, fixed in the air,
when the atmofphere was loaded with lightning, might
draw from it the matter of thunderbolts, without noife
or danger, into the body of the earth. His account of
this fuppofition is given by himfelf in the following
words : “ The eleClric fluid is attraCled by points. We
do not know whether this property be in lightning ;
but fince they agree in all the particulars in which we
can already compare them, it is not improbable that
they agree likewife in this. Let the experiment be
made.” 441
In the year 1752, while waiting for the ereCtion of exPeri-
a fpire in the city of Philadelphia, not imagining that (^wri
a pointed rod of a moderate height could anfwer theiig{ltnjng
purpofe j at laft it occurred to him, that, by means from the
of a common kite, he could have readier accefs to the clouds,
higher regions of the atmofphere than any other way
whatever. Preparing, therefore, a large filk handker¬
chief, and two crois flicks of a proper length on which
to extend it, he took the opportunity of the firft ap¬
proaching thunder-ftorm to take a walk into a field
where there was a ftied proper for his purpofe. But
dreading the ridicule which too often attends unfuccefs-
ful attempts in fcience, he communicated his intention
to nobody but his fon, who aflifted him in railing
the kite. A confiderable time elapfed before there
w7as any appearance of fuccefs. One very promifing
cloud had paffed over the kite w ithout any effedlj w’hen,
juft as he was beginning to defpair, he obferved fome
Chap. I. ELECT
Atmo- loofe threads of the hempen firing to Hand ereft, and
fpherical avoid one another, juft as if they had been fufpended
Eledtridty. ^ tjie conduaor of a common electrical machine. On
‘ v this he prefented his knuckle to a key which was faften-
ed to the firing, -and thus obtained a very evident elec¬
tric fpark. Others fucceeded, even before the firing
was wet j but when the rain had begun to defcend, he
collected eleftric fire pretty copioutly. We are told,
that when he faw the fibres of the firing eredt them-
felves, he uttered a deep figh, and wiftred that moment
to be his laft, feeling that by this difcovery his name
would be immortalized. He had afterwards an infula-
ted iron rod to draw the lightning into his houfe } and
performed almoft every experiment with real lightning,
that had before been done with the artificial reprefenta-
tions of it by eleclrical machines. That he might lofe
no opportunity of making his experiments, he connect¬
ed two bells with his infulated rod ; and thefe by their
ringing, gave him notice wdrenevcr his apparatus wTas
electrified by the lightning.
Although we have recounted Dr Franklin’s experi¬
ments firft, he was not however, the firft who verified
his own hypothefis. This was done in France, about
a month before Dr Franklin’s experiments with the
kite.
Tile iden- The moft active perfons were two French gentlemen,
tity of Meflirs Dalibard, and Delor. The former prepared his
and deftri aPParatus at Marly la ville, fituated about five or fix
chy firft leagues from Paris •, the latter at his own houfe, which
difiovered was on fome of the higheft ground in that capital,
m France. Mr Dalibard’s apparatus confified of an iron rod, 40
feet long, the lower extremity of which was brought
into a fentry box where the rain could not enter 5 while
on the outfide, it was fafiened to three wooden, ports,
by filken firings defended from the rain, ihis ma¬
chine was the firft that happened to be favoured with a
vifit from the ethereal fire. Mr Dalibard himfelf was
not at home *, but, in his abfence he had intrufted the
care of his apparatus to one Coifier a joiner, who had
ferved 14 years among the dragoons, and on wirofe
courage and underftanding he could depend. I his ar-
tifan had all the neceffary inftru&ions given him •, and
was defired to call fome of his neighbours, particularly
the curate of the parifh, whenever there firould be any
appearance of a thunder-ftorm. At length the long-
expefled event arrived. On Wednefday the 10th of
May 1752, between two and three in the afternoon,
Coifier heard a pretty loud clap of thunder. Immediate¬
ly he ran to the machine, taking with him a vial fur-
nifhed with a brafs wire ; and prefenting the ware to
the end of the rod, a fmall fpark iflued from it with a
fnap like that of a fpark from an ele&rified conductor.
Stronger fparks were afterwards drawn, in the prefence
\ of the curate and a number of other people. The cu¬
rate’s account of them wras, that they were of a blue
colour, an inch and a half in length, and fmelled
ftrongly of fulphur. In taking them, he received a
ftroke on his arm, a little below the elbow ; but he
could not tell whether it came from the brafs wire in-
ferted into the phial, or from the bar. He did not at¬
tend to it at the time, but the pain continuing, he un¬
covered his arm wdren he went home, in the prefence
of Coilier. A mark was perceived round it, fuch as
might have been made with a blow of the wire on his
•caked Ikin.
Vol. VII. Part II.
R I C I T Y. 777
Eight days after, Mr Delor witneffed the fame ap-
pearances at his own houfe, though only a cloud pafled
over, without either thunder or lightning. His appa- ,.. _v — 1
ratus differed little from that of Mr Dalibard, except
that his rod was 99 feet high, and anfivered rather bet¬
ter than that of the other gentleman. As it was found
that only a fmall quantity of eleclric fluid could be col-
lefted by a Angle pointed rod, thefe experimentalifis
added to this apparatus a number of infulated iron bars,
communicating with the pointed iron conductor, con-
ftituting what they called a magazine of eledrici-
ty. _ . . . i
Dr Franklin having proved the identity of lightning 44$
and electricity, was defirous of afcertaining whether the
electricity produced from the clouds wTas pofitive or
negative. The firft: time he fucceeded in making an
experiment for this purpofe, w^as on the 12th of April
1-753, when the lightning appeared to be negative.
Having found that the clouds eledrified negatively for
eight fucceflive thunder-gufts, he concluded that their
eledricity was always negative, and fet about forming
a theory to account for this. But he afterwards found
he had concluded too foon. For on the fixth of June
following, he met with one cloud which was eledrified
pofitively $ upon which he correded his former theory,
but did not feem able perfedly to fatisfy himfelf with
any other. The Dodor fometimes found the clouds
would change from pofitive to negative eledricity
feveral times in the courfe of one thunder-guft, and he
once obferved the air to be ftrongly eledrified during
a fall of fnow, wdien there wTas no thunder at all.
The experiments of Dr Franklin and M. Dalibardj
wrere foon known over all Europe, and the eledricians
of every country were eager to participate in the glory
and fatisfadion to be derived from fuch grand under¬
takings. M. M. Mazeas, Monnier, and de Romas in
France, Canton and Wilfon in England, and above
all, Beccaria in Italy, made a number of interefting ex¬
periments on the eledricity to be drawm from the clouds,
and foon difcovered that figns of eledricity might be
obtained, not only during thunder-ftorms, but almoft:
at all times, and in every kind of weather. But be¬
fore we relate thefe obfervations, we muft conclude our
prefent fubjed. We ftiall only here defcribe Dr Prieft-
ley’s method of conftruding a thunder-rod for making
fuch obfervations. 444
“ On the top of any building, which will be the Method of
more convenient if it ftand upon an eminence, ered ^onftnic-
pole as tall as a man can well manage, having on the^”^^"0'
top of it a folid piece of glafs or baked wTood a foot in
length. Let this be covered with a tin or copper vef-
fel in the form of a funnel, to prevent its ever being
wetted. Above this, let there rife a long flender rod,
terminating in a pointed wire, and having a fmall wire
twifled round its wEole length, to condud the eledri¬
city the better to the funnel. From the funnel make
a wire defcend along the building, about a foot diftance
from it, and be conduded through an open fafti, into
any room which (hall be moft convenient for making
the experiments. In this room let a proper condudor
be infulated, and conneded with the wire coming in at
the window. This wire and condudor, being com¬
pletely infulated, will be eledrified whenever there is a
confiderable quantity of eledricity in the air ; and no¬
tice will be given when it is properly charged, either
5 F V
778
Atmo-
fpherical
Elcdlricity.
^ Priejlley'i
Hijl. part v.
fecfl. t.
445
by Mr
bells
E L E C T R
Canton’s balls hung to it, or by a let of
Sect. II. Of the Phenomena
ning.
A thunder-ftorm commonly
and Effects of Light-
commences in the fol-
Promefs of ^owl'np manner. At iirft a low denfe cloud begins to
a thunder ^orm in a P^rt of the atmofphere which was previouily
ftorm. clear ; this cloud increafes fall, but only from its upper
part, and fpreads into an arched form, appearing like
a large heap of cotton wool. Its lower furface is ge¬
nerally level, as if it relied on a fmooth plane. The
wind is all this time very gentle, and frequently it is
imperceptible.
Numberlefs fmall ragged clouds, like teazled flakes
of cotton, foon begin to make their appearance, moving
about in various directions, and perpetually changing
their irregular furface, appearing to increafe by gradual
accumulation. As they move about, they approach
each other, and appear to llretch out their ragged arms
towards each other ; they do not often come in contaft,
but after approaching very near each other, they evi¬
dently recede, either in whole, or by bending away their
ragged arms.
While this irregular motion continues, the whole
mafs of fmall clouds gradually approaches towards the
large cloud which firit appeared, and with which they
finally coalefce; frequently, however, uniting with
each other into larger maffes, before the general coalef-
cence takes place. The upper cloud often increafes
by acceflion of freflr vapour, without any aflillance from
the fmaller maffes. When this happens, its lower fur¬
face, which was before level and regular, becomes rag¬
ged, and llretches out its irregular tatters towards each
other, and towards the earth. The clouds now thick¬
en fail, moving about fwiftly in all directions, and
flalhes of lightning are feen to dart from one cloud to
another; the wind now rifes or increafes, generally
blowung in fqualls. The lightning becomes more fre¬
quent, linking between the clouds and the earth, often
in two places at once ; ftalhes of various lhapes and
various brilliancy are produced, and frequently a vail
expanfe of horizon appears in one blaze of light. The
thunder is now heard to roar at a diftance, gradually
approaching nearer, and foon fucceeded by heavy
rain *.
The circumltances to be noticed as attending a thun-
der-llorm, chiefly refpeft the form and colours of the
lightning, the found of the thunder, and the devalla-
tions produced when an explofion takes place between
a cloud and fome imperfeClly conducting body on the
furface of the earth.
The form of the flalh is various, but in ordinary
lightning it is generally angular, or ,zlg-‘zag j this zig¬
zag is fometimes larger than at others, and in fome in-
Itances the flalh is divided into feveral diltinCt currents.
Thefe diverfities might be expefted from the heteroge¬
neous nature, and various conducting powmr, of the fe¬
veral fubllances which float in our atmofphere. As
thefe fubllances are placed in no certain order, the elec¬
tric fpark, in palling through the air, and linking fuc-
ceflively from one of thefe bodies to another, as fo
many llepping Hones irregularly placed, can feldom
obferve the fame tract, and hence its zig-zag appear¬
ance.
*•- Beccaria
Lett, del
elettr'uifme.
446
Form of
the flalh.
I C I T Y. Party.
Sometimes the flalh appears as one denfe ball of Atmo-
fire, efpecially when it ftrikes from a cloud to any part fy^bcal
of a building, when it is generally deferibed as a globe ~tS'le(^aty;
of lire falling on the building. ^
The colours of the flafli are alfo various j pale llraw Colours of
colour, vivid yellow, and various lhades of blue, are thedie
moll prevailing tints. Thefe various colours probably
depend on the dilferent denlity of the air through which
the light has palled, or perhaps, on its different nature.
We found, when relating the experiments of Mr Mor¬
gan on the appearance of the eleClric light in rarefi¬
ed air, that its colour varied with the degree of rarity
produced in the exhaulled receiver •, and from the
experiments on palling the eleclric fpark through vari¬
ous gafes, we found that the colour of the light varied
conliderably with the nature of the gas through which x
it palfed.
Lightning very often appears without being fucceed- ciaplff
ed by thunder, but we believe there is fcarcely an in- ihunder al¬
liance where the latter is not preceded by the former j ways Pre-
we fay, fcarcehj an infance, for we have on record in y a
the 77th volume of the Philofophical Tranfaclions, an
account of a thunder-llorm that happened on the banks
of the Tweed in 1785, in which an explofion took
place that killed a man and two horfes, but was not
preceded by any flalh. The refpeftable recorder of
this account, Mr Brydone, was not himfelf a witnefs of
the accident, but could not learn from the perfons
whom he interrogated, (two Scotch peafants), who had
feen the accident, that there was any preceding flalh of
lightning. In fuch lingular circumfiances, and with
fuch doubtful authority, we Ihould be difpofed to fuf-
pend our belief, and, until fome fimilar inftance better
authenticated lhall occur, to take it for granted, that
a clap of thunder is always preceded by a flalh of light-
ning.
The found which attends the explofion of the light- SoumHY
ning, varies according to the difiance from which it is the explo-
heard, and the nature of the country where the ttorm f10n‘
takes place. At a little diftance, it is generally a
hoarfe grumbling noife, whicli appears to extend through
a confiderable part of the atmofphere, and gradually
dies away. If it be heard very near, the cralh is in-
fiantaneous, and exactly fimilar to the explofion of a
cannon, when we are very near it at the time of its be¬
ing fired.
When the explofion begins very near, the fnap be¬
gins with great fmartnefs, and for fome time refembles
the violent tearing of a piece of ftrong filk j but it be¬
comes more mellow as it proceeds to a greater dif¬
tance.
If the country where the ftorm happens be high and
irregular, where there are numerous objedls capable of
reverberating the found, the explofion confifts of a long
and broken fucceflion of claps, the loudnefs of which
varies more according to the nature and circumftances
of the reverberating objefts, than according to the
length of time which intervenes between the claps. In
a level and low country, where there is no diverfity of
reverberating obje&s, and particularly at fea, the feries
of explofions is regular, and their loudnefs decreales as
the length of time increafes.
The explofion of thunder differs from the fnap pro¬
duced by the eledtric fpark, or even the explofion of a
jar or a battery, not only in its degree of loudnefs, but
in
Chap. I.
electricity.
ploflon.
45* .
Manner m
which the
explofion
Atmo- in its nature } it is a long-continued, rumbling, une-
fpherical quable noife. The long-continued roar of thunder, is
Eiedtricity. certainly owing to the commencement and termination
of the explofion reaching our ears at. different periods
of time; and the unequally loud rumbling noife is owing
to the different parts of the explofion linking the ear
45o in a different manner. .
Method of It will not be improper here to mention the method
meafuring i which the diftance of a thunder-ftroke may be afcer-
the diftance g obferving the flalh, and counting, by means
eX' of a watch with afecond hand, the number of feconds
which elapfe between the appearance of the llaffi and
the commencement of the roar, this may be ealily e -
fecled •, for we know that found travels at the rate of
186,768 feet in a minute : by reducing the time obferved
between the flafh and the report, into feconds, and al¬
lowing for each its proper number of feet, we obtain,
with fufficient accuracy, the diftance of the ftroke fiom
the place of obfervatien.
To underftand the manner in which the explolion ot
thunder is produced, we muft obferve, that the air 0
takes^dace the atmofphere is often arranged in ftrata, and thefe
ftrata are bounded by clouds. That the clouds are ftrati-
fied, is very evident. From various caufes, to be ex-
* plained hereafter, thefe ftrata, or the oppofite furfaces
of h particular ftratum, are poffeffed of oppofite ftates of
eleftricity, or the ftratum becomes charged as the plate
of air between the two coated boards, defcribed in N
235. Numberlefs experiments have proved, that du¬
ring a thunder-ftorm, there is a contemporaneous accu¬
mulation and deficiency of the eleclric tiuid, or that
there are two parts in the atmofphere, that are in the
oppofite ftates of pofitive and negative eledlricity. Hence
' we may eafily conceive the nature 01 the exploiion j for
when the accumulation and deficiency, on the oppofite
furfaces of the ftratum of air, have attained a ceitain
height, a diicharge muft take place, fimilar to the fpon-
2 taneous difcharge of a Leyden phial.
Generally The explofion commonly takes place in the heavens,
confined to and is merely the reftoration of the equilibrium between
the heavens, oppofite clouds j but m fome inftances, the explofion
happens between the clouds and the earth. In this lat¬
ter cafe, it is believed by moft eleiftricians, that the
earth is in the negative ftate •, but Mr G. Morgan is of
opinion, that the deficiency is never in the earth, but
in fome other cloud to which an eafier paftage is found
through fo good a conductor as the wet earth, than
through the air, which is an imperfect conductor. Mr
Morgan brings a great many arguments in fupport of
his opinion, but for thefe we muft refer to his lectures.
It is of little confequence to our prefent purpofe,
whether the deficiency is in the earth or in fome adja¬
cent cloud •, it is fufficient to know, that lightning
ibmetimes ftrikes from the cloud to the earth, or from
the earth to the clouds. When this happens, and when
the accumulated fluid comes in contact with any body
that is an imperfeft conductor, fiich as trees, buildings,
&.c. it produces thofe devaftations which are fometimes
the attendants of fevere thunder-ftorms } thefe, therefoie,
453 wye are now to confider. _ _
Effects pro- Lightning, when it ftrikes a building, for the moft
duced hy t attacks the higheft parts of it, as the chimneys, or
on abuftd- fpires, efpecially if thefe are furmounted by any.metal¬
ing. lie work, which is always the cafe witn fpires or
churches, and not unfrequently on chimney-tops, where
779
iron machines have been placed to prevent fmoking.
In moft of the cafes which have been recorded ot £ie(^:rjcjty-
houfes being damaged by lightning, it has entered by u—-y—- <
the chimney, down which it teems to be conducted by
the fmoke and foot. Having entered the houfe, it com¬
monly proceeds to the beft and neareft conductors in its
paffage, particularly bell-wires, gilt cornices, rrames of
pidlures, and other gilded furniture , thefe it commonly
deftroys, fufing, and very often oxidating, the metal as
it paffes along. Some very remarkable initances are re¬
lated of the powder of lightning in fufing metals; we
have heard of the fufion of bells, of large chains, and ot
iron conducing-rods near an inch in diameter ; bm the
authority on which thefe facts are related does not feem
worthy of our implicit confidence. 1 here are inftances,
however, fufticiently credible, where the pointed end of
a conductor has been rounded, parts of leaden fpouts
melted, and the edge and point of a knife completely
ffifed. But in general the bell wires of a houfe fuffer
the moft; thefe are always ftiortened and very common¬
ly melted in fome parts •, while in others, they are en¬
tirely diftipated in oxide, marks of whicn are very com¬
monly vifible on the walls.
It has been difputed, whether the fufion of metals by
lightning be fuch a chemical fufion as is occafioned by 454
fire, or what is called a cold fufton. Dr Franklin was Fufion of
of the latter opinion j the principal.arguments for which, by
are, that money has been melted in a perfon’s pocket, ^ a co^d
and a fword within its Icabbard, without the pocket or fu{jon-
the fcabbard being deftroyed. We confefs ourfelves at
a lofs to conceive what is meant by a coldfujion, as. we
have no idea of a metallic body being fufed at^all,^i. e.
reduced into thofe globular forms which metals that na\ e
been fubjefted to the a&ion of lightning and cle&ricity
ufually affume, but by the power of a. degree of heat,
which would, when applied to bodies lufticiently inflam¬
mable, fet thefe on fire. . 455
That the explofion of lightning frequently does this, Lightning
is fufficiently certain. In the ordinary cafes, indeed, of fets fire to
a building’s being ftruck by lightning,, inflammation
does not enftie, becaufe the parts of the building through k0(pies.
which the fluid paffes, are either in their nature, very
little inflammable, or are fo hard and denfe in their tex¬
ture, that they are not eafily inflamed. But when the
building attacked contains matters of a veiy comb.uiti-
ble nature, fuch as hay, ftraw, and more efpecially
gun-powder, a fire is very commonly the confequence j
and accordingly, w^e every now and then hear of inftances
of ftables being burned, and powder magazines blown up
by lightning. _ 456
When the lightning in its courfe meets with any ob- Tears nidi
ftruftion, as in palling through a body which is an im-bodies as
perfeft conductor, it overcomes this obftruction by for- ref«
cing a paffage through the refilling body : hence, we very Pa“aSe'
commonly find large beams lhattered, and ftones and
bricks either driven from their places, or fplit and. per¬
forated in an unequal manner. Frequently, the light¬
ning will forfake one conducting body, as the handle of
a bell-wire, and ftrike through the wall of the room, at-
trafted by fome conduftor, either of greater power or
larger dimenfions, fuch as a kitchen grate, on the other
" 1 This eff-a of lightning is exadtly fimilar to the
fide.
perforation and rending of bodies by^electricity, as we
related when treating of the mechanical effects of that
power ; it is undoubtedly owing to the fudden expanfion
5 F 2 of
780
Atmo-
Ipheiical
KJedt'ricity.
457
Deltroys
animals life
458
Death of
Profeffor
Richman
by light-
ning.
ELECT
of the air or moifturc contained witliin the pores of the
relifting body.
We have leen that animals are deftroyed by lightnincr*
but tiie effedls of this power on the animal body come
to be explained with more propriety in a future part of
this work, where we ftiall treat of the effeds of eledri-
city on vegetable and animal life.
We fhall here only relate the unfortunate death of
the celebrated Profeffor Richman of St Peterlhurgh.
This happened on the 6th of Auguft 1753, as he was
making experiments on lightning drawn into his own
room. . He had provided himfelf with an inftrument for
meafuring the quantity of eleftricity communicated to his
apparatus j and as he ftood. with his head inclined to it, IVTr
Solokow an engraver, who was near him, obferved a g’lobe
of blue fire, as big as his fift, jump from the inftru¬
ment, which was about a foot diftant, to Mr Richman’s
head. The profeffor was inftantly dead, and Mr Solo¬
kow was alfo much hurt. The latter, however, could
give no particular account of the way in which he was
affeded; for, at the time the profeffor was ftruck,
there arofe a fort of fteam or vapour, which entirely
benumbed him, and made him fink down to the ground,
fo that he could not even remember to have heard the
clap of thunder, which was a very loud one. The
globe of fire was attended with an explofion like that
of a piftol ; the inftrument for meafuring the eledri-
city (called by the profeffor an eleBrical gnomon) was
broken to pieces, and the fragments thrown about the
room. Upon examining the effeds of the lightning in
the profeffor’s chamber, they found the door-cafe half
fplit through, and the door torn off and thrown into
the room. They opened a vein in the body twice, but
no blood followed y after which, they endeavoured to
recover life by violent fridion, but in vain : upon turn¬
ing the corpfe with the face downwards during the
rubbing, an inconfiderable quantity of blood ran out
of the mouth. There appeared a red fpot on the fore¬
head, from which fpirted fome drops of blood through
the pores without wounding the fkin. The ftioe be¬
longing to the left foot was burft open, and uncovering
the loot at that part, they found a blue mark ; from
whence it was concluded, that the eledric matter hav¬
ing entered at the head, made its way out again at
that foot. Upon the body, particularly on the left
fide, were feveral red and blue fpots, refembling leather
finunk by being burnt. Many more alfo became vi-
fible over the whole body, and particularly over the
back. That upon the forehead changed to a brownifh
red, but the hair of the head was not finged. In the
place where the ftioe was unripped, the flocking was
entire *, as was the coat everywhere, the waiftcoat on¬
ly being finged on the fore flap where it joined the
hinder : but there appeared on the back of Mr Solo-
kow’s coat long narrow ftreaks, as if red-hot wares had
burned off the nap, and which could not well be ac¬
counted for.
When the profeffor’s body w^as opened next day, the
cranium was very entire, having neither fiffure nor’eon-
tra-fiffure : the brain was found ; but the tranfparent
pellicles of the windpipe were exceflively tender, and
eafily rent. ’There was fome extravafated blood in it
as alfo in the cavities below the lungs. Thofe of the'
breaft w^ere quite found ; but thofe towards the back of
a brownifh black colour, and filled with more of the
Part V,
Atmo-
fpherical
Electricity.
L I c I T Y.
blood above mentioned. The throat, the glands, and
the fmall inteftines, were all inflamed. The finged lea¬
ther-coloured fpots penetrated the fkin only. ° In 48
hours the body was fo much corrupted, that they could v —
fcarcely get it into a coffin, 4_9
From the dangers to which perfons and buildings are Diftance at
expofed from lightning, it becomes an objedt of im-which tlie
portance to afeertain the diftance at which they may be expIo,flon
confidered as fecure from its influence. The following Serous
obfervations of Mr G. Morgan on this fubjedl are re¬
plete with ingenuity and good fenfe. ^
I he greateft danger of a thunder-ftorm lies between Morgan’s
the tvvo neareft extremities of the correfpondent parts Qbk'iva-
of the charged atmofphere, or in that interval of un-tions*
eh ft rified air which is always found to feparate the pofi-
tive from the negative portion of the loaded cloud : but
on either fide of this interval, the further you get into
the pofitive or the negative, the more does the power of
injuring diminilh.
“ The idea which I now wifh to imprefs, will be illufi-
trated by the following circumftances of faft.
“ Take a Leyden phial, five inches in diameter, and
thirteen or fourteen inches in height. On the infide
let the coating rife till its upper edge be two inches and’
a half from the rim of the veffel. On the outfide, let
the coating rife no higher than one inch from the bot¬
tom. When the phial is thus coated, let it be charged,
and a fpark will pafs from the tin-foil on the outfide to
that on the infide j but its form wall refemble that of 2
tree, whofe trunk will increafe in magnitude and bril¬
liancy, and confequently in power, as it approaches^ the
edge, owing to ramifications which it collefts from all
parts of the glafs. Within twm inches of the edge it be¬
comes one body or ftream, and along that interval its
greateft force acts.
“ When two clouds, or the two correfpondent parts of
a cloud, have their equilibrium reftored by a difeharge,
the appearances are exaftly fimilar to thofe of the pre¬
ceding experiment. [Each extremity of the flafh is
formed by a multitude of little ftreams, which gather
into one body, whofe power is undivided in that in¬
terval only which feparates the pofitive from the ne¬
gative.
“ In this country thefe appearances are frequently feem
but they are moft commonly hidden by intervening
clouds. While I wais pafling over Mount Jura, one
night during a thunder-ftorm, the flaflies fucceeded each
other fo rapidly, that about thirty ftruck within each
minute, but owing to the height of my fituation at that
time, not one of them appeared otherwife than partially
or generally, according to the defeription I have juft
given. Sometimes a lower cloud would hide one of the
tw'o charged parts, and in this cafe the lightning af-
fumed the form of a tree, wTofe trunk and branches on¬
ly appeared. Sometimes the trunk was hidden, and
then the ramifications on each fide w^ere alone vifible.
Frequently intervening clouds wmuld hide all but the
trunk, and the lightning then appeared as it commonly
does to a fpeftator in a low fituation.
“ It muft be obvious from the preceding ftatement of
circumftances, that the greateft devartation of lightning
muft take place in that interval through which the
whole body of the fluid paffes, and that as you penetrate
further and further into the cloud, the ftream that is
formed becomes lefs and lefs, like a river which dimi-
niflies
Chap. I.
E L E C T R
Atmo- niiTies by entwifling itfelf as you approach its fountain,
fpherical Hence to us placed on the ground, no danger can ever
Electricity. occur? t;n the clouds are fo low, that the ftriking di-
' v ' ftance through air, or the aerial interval between the
charged parts, refills the paffage more powerfully than
the body of earth, and any additional portion of atmo-
fphere which may lie in the dire&ion of the earth from
the flriking interval.
“ If the charged cloud lies in contaft with the ground,
its paflage to the earth will be that of feveral ilreams,
and the danger will be great, in proportion to the mag¬
nitude of that feparate dream which palfes through any
given part of the earth •, and feveral diilincl fituations
may be thus unequally endangered at the fame time.
Hence it happens, that-the fame droke will frequent¬
ly injure feveral dillinfl buildings, which are very near
to each other, and that different degrees of injury are
always obferved in the different trails.
“ The driking didance, or the length of the interval
of greated danger, will vary with the height of the
charge, and not with the dimenfions of the charged bo¬
dy. This is clear from a multitude of fads already il-
ludrated and applied. We may hence fafely conclude,
that the longer any charged cloud is in the vicinity of
the wet ground, the more will the length, and con.
fequently the danger, of its driking didance be dimi-
niihed, provided the points and prominences, which
are active on the ground, difcharge the fluid more
abundantly than it is accumulated by the producing
•caufe.
“ From what I have already faid, it is clear that all
the parts of the circuit, through which a thunder cloud
may difcharge its contents, are not equally dangerous,
and that the maximum of danger is confined within
much narrower limits than thofe of the interval, wititin
which it may be felt in one inferior degree or another.
You mud however perceive, that as the cloud en¬
larges, the number of additions increafes, by which the
great body of the fiadr is formed, and that the length of
the mod dangerous interval will always increafe with,
and bear a certain proportion to, the diameter of the
cloud. In our attempts to edimate this diameter, wTe
may folknv twro methods, which have been recommend¬
ed 5 but I cannot fay that either of thefe methods has
any great pretenfions to accuracy.
“ id, If you meafure the fpace on which the thunder-
fhower falls, it is faid that you meafure what is com-
menfurable with the dimenlions of the thunder-cloud.
In a mountainous country this meafurement is very
poffible •, for the body of the fhower may be feen at a
fmall didance, wrell defcribed upon the elevated grounds
whofe parts it feparates from the eye. Its diameter,
therefore, may be correctly eflimated from the di-
ilance of thofe well known objects by which it is
bounded. Thofe thunder-fhow^ers, which I have ob¬
ferved, have varied in their diameter, from five hundred
yards to twro miles. It is, however, to be obferved,
that the partial vacuum, produced by the collapfe at¬
tending the removal of the eleftric fluid, may extend its
influence to a greater didance, and caufe the fall of rain,
by rarefying the atmofphere, far beyond the bounds of
the charged cloud.
“ 2dly, The velocity of a cloud may be known by
meafuring its height, and the time which any fixed ap-
I C I T Y. „ 781
pearance in it takes to defcribe a certain angle. This Atmo-
may be done in a very fmall portion of time, and wdien
it is done, you are next to watch the moment at which f ^ ' 1
it begins to affedl your elevated conduftor, and with e-
qual accuracy you are to mark the evanefcence of its
figns. The knowledge of thefe circumdances, united
with that of the cloud’s velocity,’will correctly determine
its dimenfions.
“ From a diary in my poffeflion, made by Mr Brook,
it does not appear that the fame ele&ricity ever lad- -
ed more than fifteen minutes. When the fymptoms
of approaching thunder wrere decifive, the oppofite elec¬
tricity generally laded as long, and the interval of time
between the two eledlrics feldom exceeded one-tenth of
the wdiole.
“ If we allow, that the cloud in this cafe moved at the
rate of eight or ten miles in an hour, its diameter mud
have been four miles. However, in many indances, all
the above-mentioned changes of eledlricity took place in
two minutes. This happened feveral times fucceflively,
and each feries of changes terminated by a flafli of light¬
ning. In all indances of this kind, to make the dia¬
meter of the cloud half a mile, we mud fuppofe that it
moves at the rate of thirty miles an hour 5 and in fuch
a cafe, one-tenth of the whole, or the interval of greated
danger, would not exceed a hundred and eighty yards.
But on the fuppofition that the fize of the cloud were
fuch as to drike over the didance of two miles, many
are tire circumdances which, on its defcent towards the
ground will encroach upon its offenfive powers, change
its diredlion, or decreafe and perhaps altogether annihi¬
late its violence..
“ 1. Innumerable points and prominences rife from
the whole furface of the earth over which it hangs.
Thefe adl as fo many channels, through which its con¬
tents will find a rapid evacuation. In the power of
carrying off the fluid gradually, I have been able to dif~
cover but little difference between partial and metallic
conduflors. It fliould be added, that the torrent through
an elevated wire is fuch, when the cloud approaches it,
as would difcharge a battery, whofe furface equalled four
or five acres, in twenty or thirty feconds. When, there¬
fore, millions of other condu&ors are ading with equal
effect at the fame moment, that mud be an immenfe
cloud indeed, whofe flriking didance in fuch circumdan¬
ces is not much leffened, or whofe flriking powers are
not altogether exhauflcd..
“ 2. Metals alone condud the fluid better than
charged furfaces. If a plate of glafs, coated on one fide
with tin-foil, be charged and placed in a circuit, fo that
the contents of ajar may pafs over the other fide un¬
coated, the luminous driking didance will be quadru¬
ple what it is in air. Such, a combination of changes
as that which I have now defcribed mud frequently
occur in the upper regions of the atmofphere for the
charged clouds muff lie in ftrata above each other ; and
in the varieties of their motions, produced by their mu¬
tual attradions, and by the innumerable caufes which
affed their different currents, they mud be perpetually
ferving as difcharging-rods to one another. We confe-
quently find that nine hundred and ninety-nine flaflies
out of a thoufand, drike from cloud to cloud through
the intervening air*.” * Morgan 1
Severe (hocks have been fometimes experienced from Le^ures,
„ vol. ii.
a.
782
Atmo-
fpherical
Eledlrkity,
ELECT
461
Danger
from di-
ftant thun
-der.
462
Lord Stan-
hope’s
theory of
the return¬
ing ftroke.
^ Mahon s
Principles
of Eleftri-
city, p. vii.
•* Phil.
Vranf.
vol. Ixxvii.
•\ Morgan s
p.c£hires,
■vol. ii.
• p. 171.
a flafli of liglitning, when the perfon or building flruck
has been at a very confiderable diftance from the cloud
\ in which the dil’charge appeared to take place. A per¬
fon at Vienna received a terrible Ihock from a thunder-
rod, on which his hand relied during an explofion that
happened at the diltance of three miles from the place
where the condu&or, was eredled ; and it is fuppofed
that a fhock might be felt, or even a perfon killed, at
a dirtance “ prodigionfly greater.” It is certain that
during a thunder-ftorm, the infulated conducior is af-
fefted at every explofion, however great, fo as to emit
fparks.
It is fuppofed by moft ele&ricians that no direB ftroke
is adequate to the production of thefe effeCts, and they
have therefore had recourfe to what Lord Stanhope calls
the returning Jjroke. The following is an abridgement
of this theory.
Let PC, fig. 122. reprefent a conduftor charged poft-
tively ; and AB a conduCIor in its natural ftate, placed
fo that one of its extremities A, may juft enter the at-
mofphere of PC. In this cafe, Lord Stanhope fays, that
the fuperabundance of PC will caufe fome of the natu¬
ral fhare of AB to pafs from A to B, where it is flop¬
ped and accumulated. By this change A is left in a
different or negative ftate, and B by the addition it has
received becomes pofitive. But when the fuperabundance
at P is taken off, the pofitive fluid at B rulhes back
to its natural place at A, and this reftoration is called
the returning Jirohe.
Again, let us fuppofe PC to be negative; and A placed
as before juft within its atmofphere. Now part of the
fluid in AB will rufh from B to A, and there being
flopped will produce an accumulation j but when PC
is difeharged, this accumulation will difappear, and the
returning ftroke will be from A to B *.
To apply this to the prefent cafe. Let us fuppofe
two clouds horizontally diftant, A and
B (in the annexed diagram), the one A
eleCtrified pofitively and the other B ne¬
gatively, to be incumbent over the fur-
face of the earth at a and b ; they will
here tend to produce the oppofite ftates, or the part of
the furface a wrill be negative and b pofaive. If now
a difeharge take place between the clouds A and B,
the fluid will rufh back from b to a ; and if conductors
are fixed at thefe places, the fluid wall rufh dowm the
conductors at />, and up that at a. The fame effects,
though in a lefs degree, wall be produced, if w'e fuppofe
the negative cloud B placed above the pofitive cloud A.
By this theory, Lord Stanhope undertook to explain
how the man and two horfes w ere killed in the thunder-
ftorm deferibed by Mr Brydone, and his Lordfhip pre-
fented a very able paper on this fubjeCt to the Royal
Society *.
This theory of Lord Stanhope has been wrell re¬
ceived, and it is no fmall teftimony in its favour that
it has obtained the fupport of fo able a philofopher as
Profeflbr Robifon. Mr G. Morgan, however, ftrenu-
oufly objeCts to this theory, on the very ferious grounds
that its principle is erroneous, its effecis overrated, and
its application unnecejjary -f. Our limits will not per¬
mit us to detail all Mr Morgan’s objections, but we
muft confefs they do not convince us of the fallacy
of the theory, although they certainly tend to invali¬
date the effeBs attributed to the returning ftroke.
4
A-f —B
a— 4X
R I C I T Y. part V,
“.Let us allow, (fays Mr Morgan), that the force Atmo-
required by the theory is rendered active in the manner rpherical
which I have juft deferibed, what reafon have we foricity;
believing that it wrould be aCtive to the degreefup- TY *
pofed ? Lord Stanhope has eftimated, that what is fe- EfFtcb 0f
parated from our natural fhare without injuring us, and l116 retum-
what may be abfent for hours without being felt, is fo ‘n^ ^roke
great in quantity as to deftroy us by its motion in re_ovcrrateL
turning.. But what are the grounds of this eftimate ?
As yet it has been juftified by no appeal, either to faCI
or experiment; and the perfon who could fay, that the
greateft poffible lofs from our natural fhare is little or
nothing, would certainly ftand upon equal, I think
rather better, grounds, than thofe wfho would make it
adequate to the fufion of metals and the deftruCtion of
life. I would add, that when the power of the returning
ftroke is magnified as it is in this theory, the rationale
of this bold eftimate is not only negleCted, but it is ne-
g ected w’here it might have been made without much
trouble.
“ Jf the returning ftroke of a thunder-cloud will de¬
ftroy large edifices, furely artificial eleClricity could pro¬
duce a fimilar ftroke which would deftroy a bird or a
moufe, or aCI on fome fcale analogous to that wdiich
it is faid to refemble. If, I fay, the returning ftroke in
nature will melt the irons of a waggon wTheel, furely,
with the grand machines which wTe are now able to
conftruft, fuch a returning ftroke might be caufed as
would melt a capillary thread of metal. But nothing
of this kind has ever been done or attempted by thofe
w’ho fupport the theory, and I am bold enough to pro¬
phecy, from the details of my owm experience, that
nothing of the kind ever will be done. j Morgan
ubi fupra.
Sect. III. Of the means of preventing udccidents from P-27S-
Lightning.
It has been well obferved, that knowledge is va-invention
luable chiefly in proportion as it is ufeful; a maxim of concfiic-
which no man ever exemplified better than Dr Frank-tors againft
lin. No fooner was the real nature of lightning afeer-j’g^ins
tained by experiment, than it was naturally fuggefted Franklin,
that this grand difeovery might be rendered beneficial
to mankind, by affording means for preferving build¬
ings from the formerly inevitable devaftations of that
powerful inftrument of nature. Here too, the genius
of Franklin led the way; and as he certainly deferves
the greateft ftiare of the merit due to the difeovery of
the identity of lightning and eleftricity, we are alfo
chiefly indebted to him for the means of applying this
knowledge to advantage. He was led to propofe the
ufe of pointed metallic condudlors attached to the
building* as a fecurity againft the effefls of lightning j
and this propofal, like moft of Dr Franklin’s ingenious
contrivances in elcdlricity, was the refult at once of
acute reafoning and accurate obfervation. ,
Dr Franklin confidered the earth as performing the His direc-
office of a condudftor, in reftoring to the atmofphere the t'ons for
eleftrical equilibrium, that had been difturbed by the ’r con*
caufcs which tend to produce atmofpherical eledlricity. ^ru<^10n‘
In its courfe, he obferves, that the lightning will com¬
monly ftrike the beft conductors •, and accordingly, as
a metallic rod is a much more perfeCt conductor .than
the ftones, bricks, &c. of which buildings are chiefly
compofed, the lightning will ftrike the rod in prefer¬
ence
Chap. I.
Atmo-
fpherical
E L
ence to tlie materials of the building.
466
Requifites
to be ob-
ferved.
467
Should be
E C T
He therefore
advifed, that a metallic rod fliould be fixed to fome
Elearicity. part of t]ie builJing? penetrating for fome diitance into
¥ the moift earth, and, as lightning does not in every cafe
fir ike the higheft parts of a building, that the rod
fliould extend for fome feet above thefe, in order, as it
were, to folicit the lightning. As lightning has been
found to deftroy metallic rods of a confiderable dia¬
meter, he advifes, that thefe conduftors Ihould be at
leaft half an inch thick, that they may the better refift
the deftrudlive power of the lightning.
From a cornparifon of numerous experiments and ob-
lervations, the following rules have been laid down for
the conftruction of condudlors.
1. T/iai the rods be made of fuch fubjlances as are in
l!;eA'Cat their nature the bfl conduBors of eleffricitij.
cob u trs. ^ js £oun(j t]iat aij metals do not condudl equally
well, and that lead and copper are the belt fitted to
ferve as condudtors againfl lightning j but as lead is
exceedingly deilruclible by eledfricity, and therefore
would require to be of a very confiderable diameter,
copper is to be preferred, as well on account of its
greater condudling power, as from its being lefs liable to
contrad! rufi than iron, which is commonly employed.
2. That the rods be of a fu fficient diameter.
q. That they be perfectly uninterrupted, or, if formed
offeveralpieces, that their junttions be as nearly in con-
tatl as pojfble.
The effect of interruptions in condudtors, as well as
the effedts of lightning in general on buildings, may be
illuftrated by the following experiments.
Exper. 1.—Fig. 1 23. fliews an inftrument repre-
fenting the fide of a houfe, either furniflied with a
metallic conductor, or not j by which both the bad
effedts of lightning ffriking upon a houfe not proper¬
ly fecured, and the ufefulnefs of metallic condudtors,
may be clearly reprelented. A is a board about
three-quarters of an inch thick, and Ihaped like the
gable end of a houfe. This board is fixed perpen¬
dicularly upon the bottom board B, upon which the
perpendicular glafs pillar CD is alfo fixed, in a hole
about eight inches diffant from the bafis of the board
A. A fquare hole, ILMK, about a quarter of an
inch deep, and nearly one inch wide, is made in the
board A, and is filled with a fquare piece of wood,
nearly of the fame dimenfions. We fay nearly of the
fame dimenfions, becaufe it mult go fo eafily into the
hole, that it may drop off by the leart lhaking of the
inftrument. A wire, LK, is faftened diagonally to
this fquare piece of wood. Another wire, IH, of the
fame thicknefs, having a brafs ball, H, fcrewed on its
pointed extremity, is faftened upon the board A 5 fo
alfo is the wire MN, which is ihaped in a ring at O.
From the upper extremity of the glafs pillar CD, a
crooked wire proceeds, having a fpring focket F,
through which a double-knobbed wire flips perpendicu¬
larly, the lower knob G of which falls juft above the
knob H. The glafs pillar DC mufi: not be made very
fall into the bottom board j but it muft be fixed fo as
to be pretty eafily moved round its own axis, by wrhich
means the brafs ball G may be brought nearer or farther
from the ball H, without touching the part of EFG.
Now when the fquare piece of wood LMIK (which
may reprefent the ftiutter of a wundow or the like) is
fixed into the hole fo, that the wire LK Hands in the
468
Should be
of luffieient
diameter'.,
and
469
Perfeiffly
continuous.
^ 470
Thunder-
houfe.
R I C I T Y. ^ 783
dotted reprefentation. IM, then the metallic communi- Atmo-
cation from H to O is complete, and the inftrument re- j-ie^icity.
prefents a houfe furnilhed with a proper metallic con- , ,-,-v—
dudlor 5 but if the fquare piece of wood LMIK is
fixed fo, that the wire LK Hands in the diredlion LK,
as reprefented in the figure, then the metallic conduc¬
tor HO, from the top of the houfe to its bottom, is in¬
terrupted at IM, in which cafe the houfe is not proper¬
ly fecured.
Fix the piece of wood LMIK, fo that its w7ire may
be as reprefented in the figure, in which cafe the me¬
tallic condudfor HO is difcontinued. Let the ball G
be fixed at about half an inch perpendicular diftance
from the ball FI, then, by turning the glafs pillar DC,
remove the former ball from the latter : by a wire or
chain conned! the wTire EF wdth the wire of the jar
P, and let another wire or chain, faftened to the hook
O, touch the outfide coating of the jar. Conned! the
ware £) with the prime condudior, and charge the jar j
then, by turning the glafs pillar DC, let the ball G
come gradually near the ball H, and when they are
arrived fufficiently near one another, you will obferve'
that the jar explodes, and the piece of wTood, LMIK,
is pulhed out of the hole to a confiderable dillance from
the thunder.houfe. Now the ball G, in this experi¬
ment, reprefents an eledlrified cloud j which, w’hen it
is arrived fufficiently near the top of the houie A, the
eledlricity ftrikes it, and, as this houfe is not fecured
with a proper condudior, the explofion breaks part of
it, i. e. knocks off the piece of wood IM.
Repeat the experiment with only this variation, viz.
that this piece of uTood IM is fituated fo, that the wire
LK may Hand in the fituation IM \ in which cafe the
condudior HO is not difcontinued j and you will ob-
fefve, that the explofion will have no effedl upon the
piece of wood LM j this remaining in the hole unmoved 5
wffiich fliews the ufefulnefs of the metallic condudior.
Further : Unfcrew the brals ball H from the wire
HI, fo that this may remain pointed, and, with this
difference only in the apparatus, repeat both the above
experiments } and you wall find that the piece of wood
IM is in neither cafe moved from its place, nor any
explofion will be heard ; which demonilrates the pre¬
ference of condudtors with pointed terminations to thofe
wdth blunted ones. 471
Exper. 2.—This apparatus is fometimes made in the Powder-
ftiape of a houfe, as reprefented fig. 124. wffiere, for the houfe.
fake of diftindtnefs, the fide and part of the roof next
the eye are not reprelented. The gable end AC re¬
prefents that of the thunder-houfe, and may be ufed in
the fame manner with that above defcribed, or more
readily by the following method. Let one ball of the
difcharging rod touch the ball of the charged jar, and
the other the knob A of the condudior AC of the
thunder-houfe ; the jar will then of courfe explode, and
the fluid will adt upon the condudior juft mentioned.-
The condudting wire at the windows h h muft be placed
in a line. The lides and gable AC of the houfe are
connedled with the bottom by hinges 5 and the build¬
ing is kept together by a ridge on the roof. To ufe
this model, fill the fmall tube a with gunpowder, and
ram the wire c a little way into the tube j then conned!
the tube e with the bottom of a large jar or battery.-
When the jar is charged, form a communication from
the hook at C, on the outfi.de, to the top of the jar, by
dijcharging
472
JEftecfts of
breaks in
vs4 ELECT
A tmo- dxfchargmg tlie rod 5 the difcharge will fire the powder,
El'S;iaty. an.d the exPlorion of the latter will throw off the roof,
with the fides, back and front, fo that they will all fall
down together. The figures/and ^ in the fide of the
houfe reprefent a finall ramrod for the tube a, and a
pricker for the touch-hole at C.
Mr Jones of Holborn quakes the front of the com¬
mon thunder-houfes, as well as the powTder-houfe above
defcribed, with two pieces of wood or windows h h,
which, by being placed in proper fituations, the one
to conduct and the other to refill the fluid, will illu-
flrate by one difcharge the ufefulnefs of good conduc¬
tors for fecuring buildings or magazines from the ex-
plofion of thunder, as well as the danger of ufmg im¬
perfect ones.
Exfier. 3.—Fig. 125. reprefents a wooden pyramid,
c on luftors ma<^e “1 feveral pieces, with a wire through each, fo
iUuftmeT’ ,i^at t^r ends may touch» as at j-j-j. Let one corner
by a pyra- t^ie pedeital d be loofe, and have the fafety wire pafs
•mid. almolt but not quite through it. Let the wire palfing
through the reft of the pedeftal join by a chain the out-
fide coating of a Leyden phial. If the cloud * be fup-
ported by a wire from the prime conductor, and hang
hall an inch from the k^ob q of the pyramid ; when
the phial is difcharged, a flalh will take place between
x and g ; the fpark will pafs along the wires sss, till
it comes to the break at d; there an explofion will
take place, that will drive out the corner-ftone d, and
overthrow the fabric.
Abundant obfervation has proved the danger of hav¬
ing difcontinuous conductors either attached to a build-
ing, or forming part of the materials. About the mid¬
dle of the laft century, the fteeple of St Bride’s church
in London was ftruck by lightning, and greatly injured.
In the conftruClion of this fteeple a great deal of iron
work had been employed 5 the ftones having been faft-
ened together in many places by iron cramps, the ends
of which were covered with fmall ftones. The light¬
ning feems firft to have ftruck the vane of the fpire,
from which it was fafely conducted down the lhaft by
which the vane was fupported ; from the extremity of
this Ihaft, it leaped to two crofs iron bars which wTere
at the bafe of the obelilk, ftiattering the obelilk in its
way. Hence it pafled to one of the above mentioned
cramps, and thus from cramp to cramp throwing out
473 or dem°lifhing the ftones as it pafled along.
Effedt of an The principles of eleCtricity afford us an eafy expla-
mtermp- nation of the manner in which the interruption of con-
duftors ads. We know that at the extremity of all
long rods there is a confiderable accumulation of elec¬
tricity, and this has here a tendency to fly off with
great force, efpecially if there is another conductor at
hand. This other conductor alfo aflifts the accumula¬
tion in the former by acquiring at its adjacent extremi¬
ty the oppofite eleCtricity. Suppofing a pofitive cloud
to be over the upper conductor, this conductor will be
eleCtrified pofitively at its lower extremity, and this ac¬
cumulation being increafed by the negative eleCtricity
of the upper and of the lower conductor, will tend to
fly off with great violence into the air, or if any ob-
ftruCtion oppofe its paffage, this will be removed by
the burlting or difplacing the refilling body.
4. It is necejfanj that the connection between the con¬
ductor and the common flock, or the earth, be as complete
as poflible.
tion ex
plained
474
Should be
properly
connedted
with the
garth.
K I c I T Y. part V.
It has been faid, that the lower extremity of the con- Atmo-
ductor ftiould be inferted fome feet below the furface of Spherical
the ground : it is alfo proper that it Ihould be turned ^leet''lclty;
in a direction away from the foundation 5 and as moif- v
ture is one of the belt conductors, it would be advife •
able, where this can conveniently be done, to conned
the extremity of the metallic rod with fome neighbour¬
ing piece of water.
5. That the rod be carried from the top of the build- Should be
ing to the commonflock in the Jhortefl convenient direction. as ftrait as
6. That the upper extremity be finely tapered, and ter- I)oQlbie*
minate in a Jharp finooth point.
There is no queftion in eleCtricity, that has been ar- Should be
gued with more keennefs, than whether thunder-rods pointed.
Ihould terminate in a ftiarp point, or in a round ball.
Dr Franklin, we have feen, decidedly gave the prefer¬
ence to a pointed conductor, and he has been followed
by molt of the eleCtricians of Europe $ Dr Wilion
Handing almoit alone in fupport of the round ball. This
controverly was renewed with great warmth on the oc-
cafion of a houfe at Puifleet belonging to the board of
ordnance, having been ftruck by lightning, although
guarded by a pointed conductor. A fet of very inge¬
nious experiments were made, both by Mr Nairne and
Dr Wilfon, to eftimate the comparative merits of
pointed and obtufe conductors j but by thefe the quef¬
tion w^as not decided j Mr Nairne’s experiments always
concluding in favour of pointed conductors, while thole
of Dr Wilfon as conftantly favoured the obtufe termi¬
nation. Moft eleCtricians, however, ftill prefer the
pointed conduCtor.
Let B (fig. 1 26.) reprefent the pofition of a charged
cloud j A, the part that is oppofitely charged, or that is
connected with it 5 FG a pointed wire. In this cafe,
the eleCtric fluid muft pafs either through the feries of
par- tial conductors, a, b, c, &c. or through the body
of earth, AF.
Now when, on the one hand, we confider the dry-
nefs of that foil which is generally feleCted for the
foundation of buildings, the probability there is that
nothing but the foil, thus dry, may leparate A from
the wire FG, and the certainty that if water fhould
conneCt A and FG, its refiftance is very confiderable j
when, on the other hand, we take into confideration,
the nails, bolts, iron bars, ftrips of lead, bell wires,
and metallic utenfils that are fcattered through all
buildings, we (hail, I think, perceive the much great¬
er probability there is qf the lightning’s palling through
a, b, c, d, &.c. to the cloud, than of its paffage through
the ground.
2. Let us ereCt another wire, HI, and ftill the dan¬
ger is almoft as great 5 for now" the poflible circuits of
the lightning are four, and of thofe, that leading through
the houfe appears to be the eafieft : if HI convey it
harmlefs, then it muft pafs through the body of the
air FG, or over the roof of the houfe. We well know
from paft experiments, that the infulating pow-er of the
air makes the refiftance in the direction IG very confi¬
derable j and even on the fuppofition that y w7ere wTet,
the refiftance over the roof of the houfe is not much
confiderable. If the houfe were covered or coped with
lead, the probability of a ftroke wmuld then be dimi-
nilhed, but not taken away ; for, fuppofe the eafieft
circuit Ihould lie in the direction KM, then, rather
than pafs through the body of earth IIK, or FK, it
might
3
Chap.
Atmo-
fpherical
'T'.lcclricity
^ 477
ajr Mor¬
gan’s pro-
pofal for
t. E I-. E C T R
might find an eaiier paffage through the houfe than ei¬
ther of the conductors. This would not be the cafe, if
a ftrip of lead, or metallic fubltance of any kind, ex¬
tended from K to H, and from K to F. “I hence
thought, (fays Mr Morgan), at one time, that a houfe
would be perfectly fafe, if a ftrip of lead were carried
around the top, and all the bottom of the building, and
then connected by two or three metallic ftrips extending
from the one to the other.
“ Let us fuppofe tlt&t a houfe were eredted over a
ftratum of moiiture, or any other conducing fubftance,
which dipped conftderably, at a little diftance from the
houfe, and then fuddenly rofe juft below it j in that
cafe, if the ftratum became the circuit of a charge, the
ftroke would rife immediately in the centre or body of
the houfe, and in all direclions would force its way
with devaftation, towards the condudtors on the out-
fide.”
To prevent all poffible danger, Mr G. Morgan pro-
pofes, that, while the houfe is building, the foundation
of each partition wall be laid on a ftrip of lead, or
Preve'Lt‘1?S that fuch ft ftrip be faftened to the fides of thefe parti-
all poffible
ttangen
, 47® r
Means of
tion walls. The ftrips ftrould be two inches wide, and
at leaft a quarter of an inch thick, and they fhould be
clofely connedled with each other. A perpendicular
ftrip on each fide of the houfe, Ihould rife from this
bed of condudlors, to the furface of the ground 5 whence
a ftrip fhould be continued round all the houfe, and
carefully connected with wTater-pipes, &c. The drips
on the fides of the houfe, fhould then be continued to
the roof, which fhould be guarded in the fame manner
as the foundation. The top fhould be furrounded by a
ftrip, whofe connection fhould fpread over every edge
and prominence, and fhould continue to the fummit of
each feparate chimney. It is particularly neceffary to
guard the chimnies *, for Mr Morgan wras witnefs to a
cafe, in which a houfe that had been guarded, in molt
refpedts, according to the foregoing directions, except
that the chimnies were unprotected, w?as ftruck with
lightning which entered by one of the chimnies : here
it fpent its fury ; but the chimney falling on the roof,
did confiderable damage.
The principal objection to this method, is the ex¬
pence attending it •, but this may be, in a great meafure
avoided, by making proper ufe of the leaden pipes,
gutters, and copings, which belong to moft houfes.
Ships, from the height and ConftruCtion of their
Srote&ing mails, and from their being fuch infulated conducting
dps* objeCts as muft neceffarily attraCt the lightning from
a cloud that is very hear, are peculiarly expofed to dan¬
ger. It is, therefore, ftill more neceffary to guard vef-
lels by proper conductors. Chains are very commonly
employed for this purpdfe, from their being more con¬
veniently difpofed among the rigging >, but it is found,
that from the want of continuity in the links, chains
are very imperfeCt conductors, and have not unfrequent-
ly been broken by a fevere fhock. Strips of lead, are
therefore, to be preferred, both as they are cheaper,
and lefs liable to be injured by the Weather and fait
wrater, than iron chains. One ftrip fhould furround the
deck, and another the bottom or fide of the keel, and
thefe fhould be connected with other ftrips, embracing
the fhip in various parts. If the fhip be copper-
bottomed, it will only be neceffary to conneCt the
topper with the deck j but in every cafe, a ftrip fliould
Vpl. VII. Part IX,
I C I T Y. 785
pafs on each fide from the reft of the ftrips to each maft.
The maft may be protected by extending a metallic
body along the flays to as great a height as poflible, , y
and connecting this with the top of the maft, and with
the reft of the conduClors furrounding the fhip. 479
The principles of eleClricity, applied to the explana- Means of
tion of the phenomena of lightning, alfo afford us fome ^fonal'1*
ufeful hints for our perfonal fecurity during a thunder- danaer>
ftorm. Thefe naturally divide themfelves into two
heads, firft, the confideration of the figns of approach¬
ing danger, and fecondly, the rules to be obferved, when
we find ourfelves within the ftriking diftance of the
cloud. 48o
1. Approaching danger may be dreaded from the Signs of ajt-
following circumftances. preaching
a. s? rapid approach of the charged clouds. The Ion- ^anSer
ger time any given portion of charged air remains over
a certain fpace, the more it is affe&ed by points and
prominences 5 but when a cloud feems to be over our
heads almoft as foon as it is formed, w7e are expofed to
the utmoft of its fury. When a cloud growp darker
and darker while it is near us, it is alfo a mark of
great danger, for w7e may be certain the accumula¬
tion is not materially leffened by an exhauftion, and
that the charge muft foon attain its ftriking height.
b» The perpendicular dir eel ion of the flajhes. This is
a certain evidence that the charged clouds are at that
height from which they can ftrike into the ground.
The appearance of two flafhes at the fame time, has
been confidered as an evidence, that the earth is aCling
as a difeharging rod but this may often happen, as
the twro extremities of the flafb, when palling behind a
cloud which partly hides it, may often give out the
fame appearance j the fign, therefore, is not fufficiently
accurate, and cannot be confidered as denoting more
than a certain degree of probable danger.
c. In making experiments with the kite, if very frong
fparks are emitted from the fringe or if a fenfation like
a cob-web puffing over the face be felt, it is time to de-
ff. This wall be fully illuftrated in the experiments
which wTe are about to relate on atmofpherical eleflri-
city.
d. In making experiments with an infulated conduBor,
if a torrent of fparks Jlxjuldflow from its interruptions,
or ffuch a torrent, after having continuedfor fome time,
Jhould fuddenly flop, and foon after recommence with an
oppoflte eledlricity, there is conflderable danger in being
near the condudlor.
2. Having afeertained, that wx are within the limits
of danger, our next objeft is to feek prote&ion ; it is
therefore neceffary to know7 how the threatened dam-
ger may be avoided. , 481
In a houfe, it is neceffary to place one’s felf at a dif- Rul‘s for
tance from all good conduftors, fuch as chimney places, !)rote<aion
gilt mirrors Or pictures, luftres, or burning candles. fiJatioiS
It is therefore proper, to withdraw into the middle of
a room, where no metallic body is fufpended from the
ceiling, and here, according to Dr Franklin, almoft:
all poflible danger may be avoided, by bringing a bed
or matrafs, and placing on it the chair on which we
fit.
If we are in the open air, and overtaken by a thun-
der-ftorm, it is proper to avoid all high and pointed
objects, except trees perhaps •, but we muft not come
very near thefe, keeping only at fuch a diftance as may
5 G prevent
786
Atmo-
fphercal
Electricity.
ELECT
prevent our being injured by the fplinters of wood, if
the tree Ihould be ftricken. It is particularly necef-
fary to avoid rivers and brooks, as thefe are excellent
conduftors.
Perhaps the bed proteftion in the open air, is a car¬
riage made fo large, as that a perfon may lit in it at a
diftance from the iides, efpecially if it be iurrounded at
the top and bottom with metallic fillets connected with
each other by a drip of the fame fubftanee.
If overtaken in a ftorm, it is fafer to be completely
wet than dry.
Chap. II. Experiments and Obfervations on the Spon¬
taneous Electricity of the Atmofphere.
482
Expei i- The firft perfon who obferved the fpontaneous elec-
me-nts on tricity of the atmofphere, was M. Monnier, who found
JaUlSrf^ha1 even when there was no appearance of lightning,
Ci\y by fonre degree of elefhdcity might generally be obferved
Monnier. in the atmofphere. His experiments were made at St
Germaine en Laye, and publifhed in a memoir read at
48^ the Royal Academy of Sciences at Paris in 1752.
Abb6 Ma- Eut more accurate experiments were made upon the
zeas. electricity of the air by the abbe Mazeas, at Chateau
de Maintenon, during the months, June, July, and Oc¬
tober, of 1753, and communicated to the Royal Society
in a letter to Dr Hales.
The abbe’s apparatus confided of an iron rod, 370
feet long, raifed 90 feet above the horizon. It came
down from a very high room in the cadle, where it
was fadened to a iilken cord fix feet long j and was
carried from thence to the deeple of the town, where
it was likwife fadened to another filken cord of eight
feet long, and dickered from rain. From the extremi¬
ty of this rod, a large key was fufpended to receive the
eleflric duid.
'When he began his experiments, viz. on the 17th of
June, the eledlricity of the air was fenfibly felt every
day, from funrife till feven or eight in the evening,
except in moid weather, when he could perceive no
figns of eleblricity. In dry weather, the rod attratted
minute bodies at no greater didance than three or four
lines. He repeated the experiment carefully every
day, and condantly obferved, that in weather void of
dorms, the eleblricity of a piece of fealing wax of two
inches long, was above twice as drong as that of the
air. This obfervation inclined him to conclude, that in
weather of equal drynefs, the electricity of the air was
always equal.
It did not appear to him that hurricanes and tempeds
increafed the ele&ricity of the air, when they were not
accompanied with thunder ; for that during three days
of a very violent continual wind in July, he was obliged
to put fome dud within four or five lines of the con-
duftor, before any fenfible attraftion could be per¬
ceived.
No fenfible alteration in the eleflricity of the air
was obferved under different directions of the winds,
except when thefe were moid.
He could obferve no eleftricity in the air during the
dried nights of fummer, but it returned in the morn¬
ing with the fun, difappearing again foon after fun-
fet.
The dronged common electricity of the atmofphere
H I C I T Y. PartV.
during that fummer, was obferved in July, on a very Atmo-
dry, clear, warm day. fpherical
On the 27th of June about noon, he perceived feme kleftneny.
dormy clouds rifing above the horizon, and obferved v ^
that the eleCiricity of the atmofphere cccafioned by
them, was increafed as the clouds reached the zenith.
Pie at this time drew confiderable fparks from his ap¬
paratus, though there was neither thunder nor light¬
ning.
The eleClricity obferved during the appearance Phil.
thefe dormy clouds, was not diminifhed by a very hea- CJ‘ranf-
vy rain, till the clouds began to didipate *. xol. xivin*
Mr Kinnerfley obferved, that when the air was in MrKm,
its dried date, there was always a quantity of ele&rici-nerlky.
ty in it, and which might be eafily drawn from it.
This, he fays, may be proved by a perfon in the nega¬
tive date of eleefricity extending his arm into the air in
the dark while holding a pointed needle in his hand j
this, however, can only be obferved when the air is
very dry.
Whether the eleftricity in the air, in clear dry
weather, be of the fame denfity at the height of two
or three hundred yards, as on the furface of the earth.
Mr Kinnerdey thought might be eafily afeertained by
Dr Franklin’s old experiment wnth the kite. The
twine, he fays, fhould have throughout a very fmall
wire in it, and the ends of the ware, where the feveral
lengths are united, ought to be tied down with a wax-,
ed thread, to prevent their afting in the maimer. of^0j
points f. . _ _ 485
Mr Canton made feveral ingenious exporiments on Mr Canton,
atmofpherical electricity, by means of his pith-ball elec¬
trometer, deferibed in N° 66. According to this phi-
lofopher, deficcated atmofpheric air, when heated, be¬
comes negatively ele£tric, and when cooled, the elec¬
tricity is of the pofitive kind, even when the air is not
permitted to expand or contract j and the expanfion or t Phil.
contra&ion of atmofpheric air occafions changes in its voIs x‘viii.
electrical date J. _
But no ele&rician, in the earlier dage of the feience, Beccatia.
conducted his obfervations in this wray with greater ac¬
curacy, or purfued them farther than Sig. Beccaria.
He obferved, that, during very high winds, his appa¬
ratus gave no ligns of being eleftrified. Indeed he
found, that in three different dates of the atmofphere,
he could find no electricity in the air : viz. in windy
and clear weather; in weather when the Iky was cover¬
ed with didimt and black clouds, that had a flow mo¬
tion ; in moid weather, not actually raining. In a
clear iky, when the w-eather was calm, he always per¬
ceived figns of a moderate electricity, but interrupted.
In rainy weather without lightning, his apparatus was
always electrified a ffiort time before the rain fell, and
during the time of the rain, but it ceafed to be affected
a little before the rain was over.
The higher his rods reached or his kites flew, the
dronger figns they gave of electricity. Alfo longer
drings and cords, extended and infulated in the open
air, acquired electricity fooner than thofe which wxre
ftiorter. A cord 1500 Paris feet long, dretched acrofs
the river Po, was as drongly electrified during a fliower
without thunder, as a metallic rod, employed to bring
lightning into his houfe, had been in any thunder-
dorm.
Having
Chap. II.
ELECT
Atmo- Having two rods for bringing the lightning into his
fphencal houfe, 140 feet afunder, he obferved, that if he took a
r.iofhicity. fparj. £roin t|le Qf thefe, the fpark from the
other, which was 30 feet lower, rvas at that inftant
leffened ; but its power again revived, though he kept
his hand upon the former.
He imagined that the electricity communicated to
the air might fometimes furnilh fmall fparks to his ap¬
paratus ) fince the air parts with the eleCtricity it has
received very flowly, and therefore the equilibrium of
the eleCtric duid in the air, will not be reitored fo foon
as in the earth and clouds.
Among the effeCts of a moderate eleftricity in the
atmofphere, Signior Beccaria confiders rain, hail, and
4S7
Rain, hail,
and (now,
fuppofed ef»
fedls of e- fnow'
leitricity.
488
Beccaria’s
idea of the
Clouds that bring rain, he thought, were produced
in the fame manner as thunder-clouds, only by a
more moderate electricity.
He notes feveral circumftances attending rain with¬
out lightning, which make it very probable, that it is
produced by the fame caufe as when it is accompanied
with lightning. Light has been feen among the clouds
by night in rainy weather •, and even by day, rainy
clouds are fometimes feen to have a brightnefs evident¬
ly independent of the fun. The uniformity with which
the clouds are fpread, and -with which the rain falls, he
thought were evidences of a uniform caufe, like that of
eleClricity. The intensity of eleCtricity in his appara¬
tus, generally correfponded very nearly to the quantity
of rain that fell in the fame time.
Sometimes all the phenomena of thunder, lightning,
hail, rain, fnow and wind, have been obferved at one
time j which Ihews the connection they all have with
fome common caufe.
Signor Beccaria fuppofes, therefore, that previous to
rain, a fmall quantity of eleCtric fluid efcapes out of the
earth, in fome place where there was a redundancy of
it; and in its afcent to the higher regions of the air,
ColleCts and conduCts into its path a great quantity of
vapours. The fame caufe that colleCts will condenfe
them more and more, till in the places of the nearelt in¬
tervals they come almofl: into contaCt, fo as to form
fmall drops, which uniting with others as they fall,
come down in rain. The rain will be heavier in pro¬
portion as the eleCtricity is more vigorous, and the
cloud approaches more nearly to a thunder cloud.
He imitated the appearance of clouds that bring rain,
by infulating himfelf between the rubber and conductor
of his eleCtrical machine, and with one hand dropping
colophcnium into a fpoon fattened to the conductor, and
holding a burning coal, while his other hand communi¬
cated with the rubber. In thefe circumttances, the
fmoke fpread along his arm, and by degrees all over
his body, till it came to the other hand that communi¬
cated with the rubber. The lower furface of this fmoke
was everywhere parallel to his clothes, and the upper
furface was fwelled and arched like clouds replete with
thunder and rain, In this manner, he fuppofed, the
clouds that bring rain diffufe themfelves from over thofe
parts of the earth which abound with the eleCtric fluid,
to thofe parts that are exhaufted of it ; and by letting
fall their rain, reftore the equilibrium between them.
This ingenious philofopher fappofes hail to be form¬
ed in the higher regions of the air, where the cold is
is very copious.
of°ha^10n intenfe> and where the eleCtric fluid
R t C I T Y. 1^1
In thefe circumftances a great riumber of particles of
water are brought near together, where they are frozen,
and in their defcent colleCt other particles, lo that the cc ^ .
denfity of the fubftance of the hailftone grows lefs and
lefs from the centre} this being formed firft in the
higher region, and the furface being collected on the
lower. Agreeable to this it is obferved, that in moun¬
tains, hailftones, as well as drops of rain, are very fmall;
there being but fmall fpace through which to fall and
thereby increafe their bulk. Drops of rain and hail
alfo agree in this circumftance, that the mere intenfe
is the eleCtricity that forms them, the larger they are.
Clouds of fnow differ in nothing from clouds of rain,
but in the circumftance of cold which freezes them.
Both the regular diffufion of fnow, and the regularity
in the ftruCture of its particles, ftiew the clouds of fnow
to be actuated by fome uniform caufe like eleCtricity.
All thefe conjectures about the caufe of hail and fnowr
were confirmed by obferYing, that his apparatus never
failed to be eleCtrified by fnowq as ■well as by rain.
A more intenfe eleCtricity unites the particles of hail
more clofely, than the more moderate eleCtricity does
thofe of fnow. In like manner, we fee thunder clouds
more denfe than thofe that merely bring rain, and the
drops of rain are larger in proportion, though they *
often fall not £rom fo great a height *. "489
Mr Ronayne obferved, that the air in Ireland was Obferva-
generally eleCtrified in a fog, and even in a mift, and tions by Mr
that both day and night, but principally in winter; Ronayna.
feldom in fummer, except from pofitive clouds or cool
fogs. The eleCtricity of the air in a froft or fog is al¬
ways pofitive. He lays, that he has often obferved,
during wThat feemed the palling of one cloud, luccefllve .
changes from negative to pofitive, and from pofitive to
negative. It may be remarked that molt fogs have a vop
fmell like an excited glafs tube 490
Mr Henly has Ihewn, that fogs are more ftrongly By Mr
eleCtrified in or immediately after a froft than at other ^eihey-
times ; and that the eleCtricity of fogs is often the
ftrongeft foon after their appearance, Whenever there
appears a thick fog, and at the fame time the air is
lharp and frofty, that fog is ftrongly eleCtrified pofitive-
Though rain is not an immediate caufe, yet Mr
Henly is inclined to confideritas a remote confequence
of atmofpherical eleCtricity; and he generally foundj
that in two or three days after he had difeovered the air
to be ftrongly eleCtrified, there was either rain or fnow.
If, in clear woather, a lowT cloud, which moves flow¬
ly and is confiderably diftant from any other, paffes
over the apparatus, the pofitive eleCtricity generally
grows very weak, but does not become negative ; and
when the cloud is gone, it returns to its former ftate.
When many whitilh clouds keep over the wire, fome¬
times uniting with and then feparating from each other,
thus forming a body of confiderable extent, the pofitive
eleCtricity commonly increafes. In all the above cir-
cumrtances the pofitive eleCtricity never changes to ne¬
gative.
The clouds which leffen the eleCtricity of the ex¬
ploring wire, are thofe which move } though thofe that
are low, feem alfo to have the fame effeCt. 4^
Mr Cavallo has confiderably improved our know- By Mr Ca-
ledge with refpeCt to atmofpherical eleCtricity, and by val!o.
his. apparatus, has greatly facilitated the means of
5 G 2 making
788 ELECT
A tmo- making experiments. His firft experiments were made
Electricity by means.of a kite ’ and af'ter bellowing much pains in
i v—- . conllru£ling kites of various dimenfions, &c. he found
492 that a common fchool-boy’s kite, .about four feet high,
Conftruc- and two wide, anfwered as well as any other. The
non Ot his ftring 0f his kite was formed by twilling together two
threads of common twine, and one of copper thread,
fuch as is ufed for trimmings. When a kite conltrudl-
ed in this manner was raifed, he always found the
firing give figns of ele&ricity, except once, when the
weather was warm, and the wind fo very weak, that
the kite could fcarcely be raifed, and could be kept up
only for a few minutes. Afterwards, however, when
the wind increafed fo that he could eafily raife the kite,
493 he obtained, as ufual, pretty llrong ligns of eledlricity.
avoid'* °f • mak^nS experiments on atmofpherical electricity
danger0^t:en attended with more or lefs danger, it is necef-
fary to obferve the following directions given by Mr
Cavallo.
“ In railing the kite when the weather is very cloudy
and rainy, in which time there is fear of meeting with
a great quantity of eleftricity, I generally ufe to hang
upon the Itring AB, fig. 1 27. the hook of a chain C,
the other extremity of which falls upon the ground.
Sometimes I ufe another caution befides, which is,
to Hand upon an infulating Itool ; in which fituation
I think, that if any great quantity of eleClricity, fud-
denly difcharged by the clouds, llrikes the kite, it can¬
not much affett my perfon. As to infulated reels, and
fuch-like inllruments, that fome gentlemen have ufed
to raife the kite, without danger of receiving any
(hock *, fit for the purpofe as they may appear to be
in theory, they are yet very inconvenient to be
managed. Except the kite be raifed in time of a
thunder-llorm, there is no great danger for the opera¬
tor to receive any Ihock. Although I have raifed my
eleClrical kite hundreds of times without any caution
whatever, I have very feldom received a few exceed¬
ingly flight Ihocks in my arms. In time of a thunder-
llorm, if the kite has not been raifed before, I would
not advife a perfon to raife it while the llormy clouds are
jult overhead ; the danger at fuch time being very great,
even with the precautions above mentioned: at that time,
without railing the kite, the eleftricity of the clouds
may be obferved by a cork-ball eleClrometer held
in the hand in an open place 5 or, if it rains, by my
eleftrometer for the rain; which will be defcribed here¬
after.
“ When the kite has been raifed, I generally intro¬
duce the Itring through a window in a room of the
houfe, and fallen it to a llrong filk lace, the extremity
of which is generally tied to a heavy chair in the room.
In fig. 128. AB reprefents part of the Itring of the
kite which comes within the room • C reprefents the
filk lace ’j DE, a fmall prime conductor, which, by
means of a fmall wire, is connected with the firing of
the kite j and F reprefents the quadrant eledrometer,
fixed upon a Hand of glafs covered with fealing-wax,
which I ufed to put near the prime conductor, rather
than to fix it in a hole upon the conduClor, becaufe the
firing AB fometimes lhakes fo as to pull the prime con¬
duClor down 5 in which cafe the quadrant eleClrometer
remains fafe upon the table : otherwife it would be
broken, as I have often experienced before I thought
of this method. G reprefents a glafs tube, about
R I c I T Y. Part V.
eighteen inches long, with a knobbed wire cemented Atmo-
to its extremity •, with -which inftrument I ufe to obferve fpher|cal
the quality of the eleClricity, when the eleClricity Qf Ekctnaty.
the kite is fo ftrong that I think it not fafe to come v"
very near the Itring. The method is as follows:—I
hold the inftrument by that extremity of the glafs tube
which is the fartheft from the wire, and touch the
firing of the kite with the knob of its wire, which, be-
ing infulated, acquires a fmall quantity of eleClricity
from it j which is fufficient to afcertain its quality
when the knob of the inftrument is brought near an
eleClrified eleClrometer.
“ Sometimes, when I raife the, kite in the night-time,
out of the houfe, and where I have not the convenience
of obferving the quality of its eleClricity by the attrac¬
tion and repulfion, or even by the appearance of the
eleClric light, I make ufe of a coated phial, which I
can charge at the firing, and, when charged, put it in¬
to my pocket; wherein it will keep charged even for
feveral hours. By making ufe of this inftrument, I am
obliged to keep the kite up no longer than is neceffary
to charge the phial, in order to obferve the quality of
the eleClricity in the atmofphere j for after the kite has
been drawn in and brought home, I can then exa¬
mine the eleClricity of the infide of the phial, which is
the fame as that of the kite.
“ When the eleClricity of the kite is very ftrong, I fix
a chain, communicating with the ground, at about fix
inches diftance from the firing *, which may carry off
its eleClricity, in cafe that this fliould increafe fo much
as to put the by-ftanders in danger.
“ Befides the above-defcribed apparatus, I have occa-
fionally ufed fome other inftruments, which I have
often varied, according as fome particular experiments
required ; but, as they are of no great confequence, I
fliall omit to defcribe them. It is only necelfary, to
give an idea of the ftandard of my quadrant eleClrome¬
ter ; which may, very probably, ftiew the fame intenfi-
ty of eleClricity under a number of degrees different
from the other inftruments of the fame kind. When
the kite is flying, and the apparatus is difpofed as in
fig. 128. I bring, under the extremity E of the prime
conduClor, a little bran, held upon a tin plate, and
obferve, that when the index of the eleClrometer is at
ten degrees, the prime conduClor begins to attraCl the
bran at the diftance of about three-fifths of an inch ;
when the index is at twenty degrees, the prime conduc¬
tor attraCls the bran at the diftance of about one inch
and a quarter 5 when the index is at thirty degrees,
the bran begins to be attraCled at the diftance of two
inches and one-fifth. Thefe diftances vary, as the
weather changes its degree of drynefs j but in frofty
weather I obferve them conftantly as above.” ^
Mr Cavallo has given copious extraCls from a jour-Inftance of
nal which he kept of his experiments with the kite j great dan-
from thefe we fliall give his account of one experiment, Ser-
which is peculiarly interefting from the danger to
which the experimenters appear to have been expofed.
“ OClober the 18th. After having rained a great
deal in the morning, and night before, the weather be¬
came a little clear in the afternoon, the clouds appear¬
ing feparated, and pretty well defined. The wind was
weft, and rather ftrong, and the atmofphere in a tem¬
perate degree of heat. In thefe circumftances, at three
P. M- I raifed my eleCtrical kite with three hundred
and
Chap. II. ELECT
Atmo- and fixty feet of firing. After that the end of the
fpherical flying had been infulated, and a leather-ball, covered
Electricity.vvjth tin-foil, had been hung to it, I tried the power
' v ' and quality of the ele&ricity, which appeared to be po-
fitive, and pretty ftrong. In a fhort time a fmall cloud
palling over, the eleftricity increafed a little -, but the
cloud being gone, it decreafed again to its former degree.
The firing of the kite was now fattened by the filk
lace to a poll in the yard of the houfe wherein I lived,
which was fituated near Iflington, and I was repeated¬
ly charging two coated phials, and giving fhocks with
them :—while I was fo doing, the electricity, which
was ftill pofitiye, began to decreafe, and in two or
three minutes time it became fo weak, that it could be
hardly perceived with a very fenfible cork-ball elec¬
trometer. Obferving at the fame time that a large and
black cloud was approaching the zenith (which, no
doubt, caufed the decreafe of the eleClricity) indicating
imminent rain, I introduced the end of the firing
through a window, in a firft-floor room, wherein I
fattened it by the filk lace to an old chair. The qua¬
drant eleClrometer was fet upon the fame window, and
was, by means of a wire, connected with the firing of
the kite. Being now three quarters of an hour after
three o’clock, the eleClricity was abfolutely unper-
ceivable } however, in about three minutes time, it
became again perceiveable, but now upon trial was
found to be negative *, it is therefore plain, that its
flopping was nothing more than a change from pofitive
to negative, which was evidently occafioned by the ap¬
proach of the cloud, part of which by this time had
reached the zenith of the kite, and the rain alfo had
begun to fall in large drops.—The cloud came farther
on 5—the rain increafed, and the eleClricity keeping
pace with it, the eleClrometer foon arrived to 150. See¬
ing now, that the eleClricity was pretty ftrong, I began
again to charge the two coated phials, and to give
fhocks with them 5 but the phials had not been charged
above three or four times, before I perceived that the
index of the eleClrometer was arrived at 350, and was
keeping ftill increafing. The fhocks now being very
fmart, I defifted from charging the phials any longer ;
and, confidering the rapid advance gf the eleClricity,
thought to take off the. infulation of the firing, in cafe
that if it fhould (Jincreafe farther, it might be filently
conduCled to the earth, without caufmg any bad acci¬
dent, by being accumulated in the infulated firing.
To effeCl this, as I had no proper apparatus near me,
I thought to remove the filk lace, and fatten the firing
itfelf to the chair j accordingly I difengaged the wire
that connected the eleCtrometer with the firing; laid
hold of the firing ; untied it from the filk lace, and
fattened it to the chair; but while I effeCled this,
which took up lefs than half a minute of time, I re¬
ceived about a dozen, or fifteen, very ftrong fhocks,
which I felt all along my arms, in my breaft, and legs ;
fhaking me in fuch a manner, that I had hardly power
R I C I T Y.
78^
enough to effeCl my purpofe, and to warn the people in Atmo-
the room to keep their diftance. As foon as I t00^ Elcdh'idty^
my hands off the firing, the eleClricity (in confequence' ^ *
of the chair being a bad conduClor) began to fnap be¬
tween the firing and the fhutter of the window, which
was the neareft body to it. The fnappings, which were
audible at a good diftance out of the room, feemed firft
ifochronous with the fhocks which I had received, but
in about a minute’s time, oftener; fo that the people of
the houfe compared their found to the rattling noife of
a jack going when the fly is off. The cloud now was
juft over the kite ; it was black, and well defined, of
almoft a circular form, its diameter appearing to be
about 40°; the rain was copious, but not remarkably,
heavy. As the cloud was going off, the eleClrical
fnapping began to weaken, and in a fhort time became
unaudible. I went then near the firing, and finding
the eleClricity weak, but ftill negative, I infulated it
again, thinking to keep the kite up fome time longer;
but obferving that another larger and denfer cloud was
approaching apace towards the zenith, as I had then no
proper apparatus at hand, to prevent every poflible bad
accident, I refolved to pull the kite in ; accordingly a
gentleman, who was by me, began pulling it in, while
I was winding up the , firing. The cloud was now
very nearly over the kite, and the gentleman, who was
pulling in the firing, told me, that he had received one
or two flight fhocks in his arms, and that if he were to
feel one more, he would certainly let the firing go ;
upon which I laid hold of the firing, and pulled the
kite in as fall as I could, without any farther obferva-
tion ; being then ten minutes after four o’clock. * r ir
“ N. B. There was neither thunder or lightning
perceived that day, nor indeed for fome days before or vol h.
afterwards 49s
From his experiments with the kite, Mr Cavallo de-Cavallo’s
duces the following conclufions.
1. The air appears to be eleCtrified at all times;
its eleClricity is conftantly pofitive, and much ftronger
in frofty, than in warm weather; but it is by no means
lefs in the night than in the day-time (*)•
2. The prefence of the clouds generally leffens the
eleClricity of the kite ; fometimes' it has no effeCt upon
, it ; and it is very feldom that it increafes it a little.
3. When it rains, the eleCtricity of the kite is gene¬
rally negative, and very feldom pofitive.
4. The aurora borealis feems not to affeCt the eleCtri¬
city of the kite.
5. The eleCtrical fpark taken from the firing of the
kite, or from any infulated conductor connected with
it, efpecially when it does not rain, is very feldom
longer than a quarter of an inch ; but it is exceedingly
pungent. When the index of the eleClrometer is not
higher than 20°, the perfon that takes the fpark will
feel the effeCl of it in his legs ; it appearing more like
the difcharge of an eleClric jar, than the fpark taken
from the prime conduClor of an eleCtrical machine.
6. The
conclufions.
(x) In all his experiments, it happened only once that the firing of the kite gave no figns of eleCtricity ; it"-
was one afternoon, when the weather was warm, and the wind fo weak, that the kite was raifed with difficulty,
and could hardly be kept up for a few minutes; in the evening, however, the wind, which in the daytime had been,
north-weft, fhifted to the north-eaft, blowing a little ftronger : he then raifed the kite again, being half paft ten.
o’clock, and obtained, us ufual, a pretty ftrong pofitive eleClricity.
ELECT
6. The ele&ricity of the kite is in general llronger
Efeftricity. "[ea,^er> according " ' * ' " '
-1; but it does not keep any exa6f
elecflrome-
ter to the
kite.
79°
A_tmo-
fpher.cal^ or wealceI.} according as the firing is longer or fliorter j
j but it does not keep any exad proportion to it: the
electricity, for inflance,^ brought dow n by a firing of a
hundred yards, may raife the index of the eleClrometer
to 20° 5 when, with double that length of firing, the
index of the eleClrometer will not go higher than 250.
7. When the weather is damp, and the eleftricity is
pretty flrong, the index of the eleftrometer, after taking
a fpark from the firing, or prefenting the knob of a
coated phial to it, rifesfurprifingly quick to itsufual place;
496 hut in dry and warm weather, it riles exceedingly flow.
Application Mr Bennet obferved with his eleCliometer, that in
of Pennet’s very clear wreather, when no clouds were vifible, on ap*
plying the inflrument to the infulated firing of kites
without metal, their pofitive eleftricity caufed the flips
of gold-leaf to flrike the Tides of the glafs ; but when a
kite was raifed in cloudy weather, with a wire in the
firing, and when it gave fparks about a quarter of an
inch long, the eleClricity was fenfible by the electrome¬
ter, at the diftance of about ten yards from the firing ;
but when placed at the diflance of fix feet, the gold-
leaf con'inued to flrike the Tides of the eleClrometer for
more than an hour together, with a velocity increafing
and decreafing with the denfity or diftance of the unequal
clouds that palfed over.
Sometimes the eleClricity of an approaching cloud has
been fenfible without a kite, though in a very un¬
favourable Tituation for it, being in a town furrounded
with hills, and where buildings encompaffed the wall
on which the eleClrometer was placed. A thunder
cloud palling, caufed the gold-leaf to llrike the Tides
of the glafs very quick at each flafh of lightning.
Mr Bennet relates the following inltance of the dan-
ger fometimes incurred in making experiments with the
kite. Having on the 5th of July 1788, raifed a kite
with two hundred yards of firing, when it had been
flying for about an hour, a dark cloud appeared at a
great diilance, and changed the eleClricity from pofi¬
tive to negative. The eleClric power increafed till the
cloud became nearly vertical, when fome large drops of
rain fell; and Mr Bennet atfempting to fecure the
firing from wet, received fuch a flrong Ihock in his arm,
as deprived it for a few feconds of fenfation. The ex-
plofion was heard at the diflance of forty yards, like the
loud crack of a whip.
The following curious phenomenon was obferved by
Mr Loammi Baldwin, while railing an eleClrical kite
ed^^Mr'7"3n I771’ ^ur^ng ^ approach of a fevere thunder-
.Baldwin dorm. He obferved himfelf to be Turrounded by a rare
medium of fire, which, as the cloud rofe nearer the ze¬
nith, and the kite rofc higher, continued to extend itfelf
with fome gentle faint flafhes. Mr Baldwin felt no o-
ther effeCl than a general weaknefs in his joints and
limbs, and a kind of lifllefs feeling ; all which, he ob-
ferves, might poffibly be the effeCl of furprife, though
it wras fufficient to difcourage him from perfifling in any
farther attempt at that time. He therefore drew in his
leite, and retired to a fhop till the florm was over, and
then went to his houfe, where he found his friends much
more furprifed than he had been himfelf; and wdio, after
exprefling their aftonifliment, informed him, that he ap¬
peared to them (during the time he was railing the
kite, to be in the midit of a large bright dame of fire,
attended with fiafhings ; and, that they expeCted every
4
497
Curious
phenome-
R 1 c I T Y. Party.
moment to Tee him fall a facrifice to the flame. The Atmo-
fame was obferved by fome of his neighbours, who lived fyhcrical
near the place where he flood *. -Electricity.
Fig. 129. reprefents a very Timple inflrument, contri-* Memoir,
ved by Mr Cavallo for making experiments on atmo-o/ the Aim.
fpherical eleClricity, and wdrich, on feveral accounts,'^* Aca.
Teems to be the mofl convenient for that purpofe. demy,
AB is a common jointed fifhing-rod, without the laflvo!'
or fmalleft joint. From the extremity of this rod pro-carlo’s
ceeds a flender glafs tube C, covered with Tealing-wax,atmofpheri-
aad having a cork D, at its end, from wrhich a pith-ball caf ekClro-
eleclrometer is fufpended. HGI is a piece of twine faf-me^er*
tened to the other extremity of the rod, and fupported at
G by a fmall firing FG. At the end I of the twine a pin
is faflened, wdiich, wdien puflied into the cork F), ren¬
ders the eleClrometer E uninfulated.
When he would obferve the eleClricity of the atmo-
fphere with this inftrument, he thrufl the pin I into the
cork D, and holding the rod by its lower end A, pro-
jeCls it out from a window of the upper part of the
houfe into the air, railing the end of the rod with the
eleClrometer, fo as to make an angle of about 50° or
6o° with the horizon. In this Tituation he keeps the
inflrument for a few feconds, and then pulling the twine
at H, difen gages the pin from the cork D; which opera¬
tion caufes the firing to drop in the dotted fituation
KL, and leaves the eleClrometer infulated and eleClri-
fied, with an eleClricity contrary to that of the atmo-
fphere.—This done, he drawrs the inflrument into the
room, and examines the quality of the eleClricity, with¬
out obilruClion either from wind or darknefs.
With this inflrument he made obfervations on the
eleClricity of the atmofphere, feveral times in a day for
feveral months, and from them he deduces the follow
ing general obfervations, which feem to coincide wTith
thofe made with the eleClrical kites.
1. That there is in the atmofphere, at all times,
a quantity of eleClricity ; for, whenever he ufed the
above-defcribed inflrument, it always acquired fome elec¬
tricity.
2. That the eleClricity of the atmofphere, or fogs, is
ahvays of the fame kind, namely pofitive ; for the elec.
trometer is always negative, except when it is evidently
influenced by heavy clouds near the zenith.
3. That in general, the flrongefl eleClricity is obfer-
vable in thick fogs, and alfo in frofly weather; and the
wTeakeft, tyhen it is cloudy, warm, and very near rain¬
ing : but it does not feem to be lefs by night than in
the day time.
4. That in 'a more elevated place, the eleClricity is
flronger than in a lowrer one ; for, having tried the at-
mofpherical eleClrometer, both in the flone and iron
gallery on the cupola of St Paul’s cathedral, Mr Caval.
lo found that the balls diverged much more in the lat¬
ter than in the former lefs elevated place ; hence it ap¬
pears, .that, if this rule takes place at any diilance from
the earth, the eleClricity in the upper regions of the at¬
mofphere mull be exceedingly flrong.
Mr Cavallo has alfo contrived an inflrument, which Hi- c.ectro-
he calls his eleBrometer for the rain ; this is merely an ueter for
infalated inflrument to catch the rain, and, by means of ra“1’
a pith-ball eleClrometer, to fhowr the degree and quality
of its eleClricity.
At fig. 130. is reprefented an inflrument of this
kind, which Mr Cavallo frequently ufed, and after
feveral
Chap. II. ELECTRICITY. 79*
At mo- fcveral obfervations, found to a&fwer very well. ABCI
fpherical js a itrong glafs tube about two feet and a half long,
Eleftncity. having a tin funnel, DE, cemented to its extremity,
' ^ which funnel defends part of the tube from the rain.
The outfide furface of the tube from A to B is covered
with fealing-wax ; fo alfo is the part of it which is co¬
vered by the funnel. ED is a piece of cane, round
which feveral brafs wires are twilled in different direc¬
tions, fo as to catch the rain eafily, and at the fame
time to make no re’fiftance to the wind. This piece of
cane is fixed into the tube, and a [lender wire pioceeding
from it roes through the bore of the tube, and commu¬
nicates with he llrong wire AG, which is thruit into a
piece of cork faftened to the end A of the tube. I he
end G of the wire AG is formed into a ring, from
which is fufpended a more or lefs fenuble pith-ball elec¬
trometer, as occalion requires.
This inflrument !s faftened to the fide of the window-
frame, where it is fupported by ftrong brafs hooks at
CB, which part of the tube is covered with a filk lace,
in order to adapt it better to the hooks. The part EC
is out of the window, with the end F a little elevated
above the horizon. The remaining part cf the inftiu-
ment comes through a hole in one of the lights of the
falh, wdthin the room, and no more of it touches the fide
of the -window than the part CB.
When it rains, efpecially in palling ftuwvers, this in-
ftrument, Handing in the lituation above deferibed, is
frequently eleclrined •, and, by the diverging of the
ele&rometer, the quantity and quality of the eledhicity
of the rain may be obiei ved, without any danger of a
miftake. With this inftrument, he obferved, that the
rain is generally, though not always eledlrified nega¬
tively, and fornetimes lo ftrongly, that he has been able
to charge a fmall coated phial at the wire AG.
This inftrument ihould be fixed in fuch a manner, that
it may be eafily taken off from the window, and replaced
again, as occalion requires •, for it will be neceffary to
clean it very often, particularly when a Ihower of rain
,00 is approaching.
Ufe of his Mr Cavallo has alfo ftiewm how the electricity of the
multiplier, atmofphere may be obferved by means of his multiplier,
deferibed in N°. 255.
In order to examine the ele&ricity of the atmofphere,
he at firft ufed to fix a long pointed wire into the focket
of the plate A, and then expofed it to the open air.
But he has lately ufed a much better method of accom-
plifhing that object. He expofes, out of the window,
an infulated flick of about five feet in length, and co¬
vered with tin-foil } and while he holds this apparatus
by the extremity of its infulating handle, he touches
with the other hand, for about two or three feconds,
the lower part of the Hick. By this means, the Hick
being free from points, acquires an electricity contrary
to that of the furrounding air. Mr Cavallo then brings
it within the room, and communicates that electricity
to the plate A of the multiplier, &c. But the eleftri-
city fo acquired by the infulated flick, is generally fuffi-
cient to affeft an eleCtrometer without the ufe of the
multiplier. To examine the electricity of the rain, fnow,
hail, &c. the fame apparatus muft be expofed out of a
window, but the flick mufl not be touched, for in this
cafe, it acquires the fame fort of electricity as that of the
rain, fnow, Sec. and not the contrary fort^ as when ex¬
pofed to the air.
Mr Read, in his “ Summary View or the Spontaneous Atmo-
EleCtricity of the Earth and Atmofphere,” obferves,
that the eieftricity of the atmofphere, in moderate wea- f ~ ‘Y y
ther, was always found to be pofitive j in ftorms and ^0i
diiturbed ftates of the air frequently negative ; and fud- Obferva-
denly and repeatedly changing from the one ftate tothet ons^y
other. Warm fmall rain, was found to be very ilightly Read’
electric j large drops, ftrongly ; hail fhowTers, the moil
intenfely of all. In an eafterly wind of long continu¬
ance, the eleCtricity was fo faint, as to require the niceft
of all known tefts for difeovering its exiftence. The
vapour of water, as foon as it had attained the height
of five or fix inches cf infulation in the air, was found
to be permanently and pofitively eleCtrified j and the
furface from which it evaporated, negatively. Accord¬
ing to Mr Read, vapour has a greater capacity for elec¬
tricity, or abforbs and requires more of fluid, than wa¬
ter in its denfer ftate j and, therefore, rarefaction muft
diminifli, and condenlation increafe, the fenftble electric
charge of the vapour. Hence, in ferene weather, the
atmofphere is fubjedl to a regular flux and reflux, or in¬
creafe and diminution of eledlricity twice in every twen¬
ty-four hours, depending on the aCtion of the fun, and
the confequent evaporation and ftate of the vapours.
This diligent obferver further remarks, that a limited
portion of the earth’s furface is often fenfibly eleffri-
fied j over it, there is always a proportionate ftate of
the contrary electricity in the atmofphere ; and when
an electrified cloud is carried forward by wind, an equal
and oppofite elediric charge keeps pace with it on the
earth, till the two charges, becoming more augmented
or approaching nearer to one another, or meeting with
fome conducting eminence, rulh together, and produce
an explofion. cr.,
W e lhall conclude our account of experiments on at- Ey Mr
mofpherical eleClricity, with thofe made by M. Sauffure Sauiime,.
in his excurfions among the Alps. The inftrument em¬
ployed by M. Sauffure is a modification of Cavallo’s at-
mofpherical eleClrometer, and (hall be deferibed under
the article Electrometer.
The following are M. Sauffure’s obfervations on the
eleClricity of the atmofphere. 503
Aerial eleClricity varies according to the fituation j it Obferva-
is generally ftrongeft in elevated and infulated fitUations ; ^
not to be obferved under trees, in ftreets, in houfes, or ele«ftricity.
any inclofed places •, though it is fometimes to be found
pretty ftrong on quays and bridges. It is alfo not fo
much the abfolute height of the places, as their fitua¬
tion : thus a projeCling angle of a high hill will often
exhibit a ftronger eleClricity than the plain at the top of
the hill, as there are fewer points in the former to de¬
prive the air of its eleClricity ,
The intenlity of the atmofpheric eleClricity is varied
by a great many circumftances, fome of which may be
accounted for, others cannot. When the weather is
hot ferene, it is impoflible to aflVgn any rule for their
variation, as no regular correfpondence can then be per¬
ceived with the different hours of the day, nor with
the various modifications of the air. The reafon is evi¬
dent 5 when contrary and variable winds reign at dif¬
ferent heights, when clouds are rolling over clouds,
thefe winds and clouds, which we cannot perceive by
any exterior fign, influence however the ftrata of air
in which we make our experiments, produce thefe
changes of which we only fee the refult, without be-
^92 ELECT
Atmo- Ing able to aflign either the caufe, or its relation,
fpherical XhllS, in ftormy weather, we fee the eleftridty flrong,
>' ^ , then null, and in a moment after arife to its former
force •, one inftant politive, the next negative 5 without
being able to affign any reafon for thefe changes. M.
Sauflure fays, that he has feen thefe changes fucceed
with fuch rapidity, that he had not time to note them
down.
When rain falls without a florm, thefe changes are
not fo hidden 5 they are however very irregular, parti¬
cularly with refpeft to the intenfity of force $ the quality
thereof is more conftant. Rain, or fnow, almoit uni¬
formly gives pofitive eleftricity.
In cloudy weather, without rain or florins, the
eledricity follows generally the fame laws as in ferene
weather.
Strong winds generally diminifh its intenfity 5 they
mix together the different ftrata of the atmofphere, and
make them pafs fucceflively towards the ground, and
thus diftribute the electricity uniformly between the
earth and the air j M; Sauffure has obferVed a ftrong
eleftricity with a ftrong north wind (7« bife).
The itate of the air, in which the eleCtricity is
ftrongeft, is foggy weather : this is always accompanied
with eleCtricity, except when the fog is going to refolve
into rain.
The moft interefting obfervations, and thofe which
throw the greateft light upon the various modifications
of eleCtricity in Our atmofphere, are thofe that are made
in ferene weather. In winter, (during which molt of
M. Sauffure’s obfervations were made) and in ferene
weather, the eleCtricity was generally weakeft in an
tevening, -when the dew had fallen, until the moment
of the fun’s riling j its intenfity afterwards augmented
fcy degrees, fometimes fooner, and fometimes later j but
t ! C I T Y. PartlVi
generally before noon, it attained a certain maximum, Atmo-
from whence it again declined, till the fall of the dew,
when it would be fometimes ftronger than it had t ncity.
been during the whole day j after which, it would
again gradually diminilh during the whole night } but
is never quite deftroyed, if the weather is perfectly
ferene‘ . . . . 504
Atmofpherical eleCtricity feems, therefore, like the Periodical
fea, to be fobjeCt to a flux and reflux, which caufes it to^ux and re«
increafe and diminilh twice in 24 hours. The moments
of its greatert force are feme hours after the riling andtjie eiec^r;
fetting of the fun*, thofe when it is weakeft, precede thecity 0f thc
riling and fetting thereof^ This will be further explain^ atmofphere.
ed in the folkwing pages.
M* Sauffure has given an inftance of this periodic flux
in eleCtricity, on the 22d of February, 1785, (one of
the coldeft days ever remembered at Geneva) 5 the hy¬
grometer and thermometer wrere fufpended in the open
air, on a terrace expofed to the fouth-wreft j the electro¬
meter, from its fituation, indicated an eleCtricity equal
to what it would have Ihewn if it had been placed on
an open plain. The height of the barometer is reduced
to w'hat it would have been if the mercury had been,
conftantly at the temperature of 10 degrees of Reau¬
mur’s thermometer. The place of obfervation was ele¬
vated 60 feet above the level of the lake. The ob¬
fervations of the day preceding and following this great
cold, are inferted in the following table j becaufe it is
pleafing to have the obfervatiohs which precede and fol¬
low any lingular phenomena. There was a weak fouth-
weft wind during the whole three days j and it is rather
remarkable, that moft of the great colds, which have
been obferved at Geneva, were preceded by, or at leaft
accompanied with, a liftle fouth-wTelt breeze.
TABLE.
Barometer,
feet in height.
h. m.
Feb. 21ft, 9 1 c M
11 10 iyi
2 10 E
5 5
6 E
7 E
8
9
10
11
12
2 2d, 1
2
E
E
E
E
E
M
M
6 15 M
7 30 M
8 10 M
9 10 M
10 10 M
11 10 M
1 10 E
2 20 E
26
26
26
26
26
26
26
26
26
26 6
26 6
26 6
26 5 J5
26 6.0
8
7
4
2
26
26
26
26
26 4 15
26 4 13
4 3
4 °
26 3 14
Thermometer.
— 8 3
— 43
— 02
— 23
— 52
— 68
— ibo
— 10 6
— 9
— 12
— 12
— x4
— M
— x5
— 14
— M
— id
— 8
— 4
— 4
+ 6
Hygfoni.
89 ;
83 !
69 I
77
85
89
95
97 ,
95
99
H r fro ft
Idem
Id.
Id.
Id.
Id.
Id.
Id.
Id.
Id.
82
EleCltom.
Pale fun, cloudy.
Bright fun*
The fame.
Setting fun.
Cloudy in the S. W.
Perfectly clear.
Idem.
Idem*.
Little cloud at horizon S.
Idem more to S* W.
Idem.
Idem.
Clouds incteafe and approach
Clear.
Light fog.
Idem.
Idem.
Thicker fog.
Idem.
Idem.
Weak fog, pale fun.
v
3
Chap. IT.
A.tmo-
fpherical
Eledlricity.
ELECTRICI TY.
h. m.
Feb. 22d, 3 30
5
6
7
8
E
E
E
E
E
23d o 45 M
8 5 M
10 7 M
3 45 E
E
E
E
E
E
Barometer,
feet in height.
5
6
7
8
12
26
26
26
26
26
26
26
26
26
26
26
26
26
*3
J3
H
r4
r3
3
3
3
3
3
5 °
5 5
6 8
6 14
7 3
7 9
7 M
9 1
Thermometer.
— O
— 4
~ 4
— 6
— 5
““ 4
— 1
— o
o
o
o
I
3
3
+
Hygrom.
Ele&rom
8l
89
91
94
Id.
Id.
81
76
76
75
74
79
87
92
1
1
2
1
3
1
1
o
Id.
1
o
2
I
O
Cloudy pale fun.
Lefs cloudy.
More fo.
Idem.
Cloudy foggy in S. W.
Cloudy with more log.
Idem.
Idem.
Cloudy pale fun.
Cloudy.
Idem.
Very clear.
Cloudy.
More fo.
M for Morning, E for Evening.
793
Atmo-
fpherical.
Electricity.
S°5 .
EleCtricity
weaker in
fummer
than in
winter.
506 _
Electricity
of the air
in ferene
weather
naturally
pofitive.
S°7
From the firft 18 obfervations of this table, when
the Iky was quite ferene, we fee that the electricity was
pretty ftrong at nine in the morning j that from thence
it gradually diminiihed till towards fix in the evening,
which was its firft minimum ; after which it increafed
again till eight, its fecond maximum $ from whence it
again gradually declined till fix the next morning,
which was the time of its fecond minimum after which,
it again increafed till ten in the morning, which was
the firft maximum of the following day : as this was
cloudy, the eleftric periods were not fo regular.
J'he eleftricity of ferene weather is much weaker in
fummer than in winter, which renders it more difficult
to obferve thefe gradations in fummer than in winter ;
befides a variety of accidental caufes, which at the fame
time render them more uncertain. In general, in fum¬
mer, if the ground has been dry for fome days, and
the air is dry alfo, the electricity generally increafes,
from the rifing of the fun till three or four in the af¬
ternoon, when it is ftrongeft : it then diminiffies till the
dew begins to fall, which again reanimates it; though
after this it declines, and is almoft extinguiffied during
the night.
But the ferene days that fucceed rainy weather in
fummer, generally exhibit the fame diurnal periods or
ftates of electricity, as are to be obferved in winter.
The air is invariably pofitive in ferene weather, both
in winter and fummer, day and night, in the fun or in
the dew. It would feem, therefore, that the electrici¬
ty of the air is effentially pofitive, and that whenever it
appears to be negative, in certain rains or in ftorms, it
probably arifes from fome clouds, which have been ex-
pofed to the preffure of the electric fluid contained in
the upper part of the atmofphere, or to more elevated
clouds, that have difcharged a part of their fluid upon
the earth, or upon other clouds.
In order to find out the caufe of thefe phenomena,
Mr Saufiiue inftituted a fet of experiments on evapora¬
tion, avoiding the ufe of Volta’s condenfer.
Fo produce a ftrong evaporation, he threw a mafs of
red hot iron into a fmall quantity of water, which was
Vox,. VIL Part IIt
contained in a coffee-pot, with a large mouth, and fuf-
pended by filk firings •, by this he obtained a ftrong po¬
fitive electricity, though, according to M. Volta’s fyf-
tem, it ought to have been negative. The experiment
was repeated feveral times, varying fome of the circum-
ftances, but the refult w’as always the fame.
As it was not eafy to think fo able a philofopher as
M. Volta was deceived, it was neceffary to try the ex¬
periment in a manner more analogous to that of M.
Volta. A fmall chafing-diffi was therefore infulated
by filk cords, and the coffee-pot, with a fmall quantity
of water, placed on it *, one electrometer was connect¬
ed with the coffee-pot, and another with the chafing-
diffi ; the fire was railed by a pair of bellows : when
the water had boiled ftrongly for a few minutes, both
ele&rometers exhibited figns of ele&ricity, which, on
examination, was found to be negative $ proving the
truth of M. Volta’s experiment. The evaporation pro¬
duced by the eftervefcence of iron in the fulphuric acid,
and by that of chalk in the fame acid, gave alfo nega¬
tive eledlricity.
It was now neceffary to inquire, why the vapour, ex¬
cited by the heated iron, produced pofitive electricity ;
while that from boiling water, in any other way, pro¬
duced a negative electricity.
M. Sauffure fufpected, that the intenfity of heat to
which the water is expofed, by the contact of a body in
a ftate of incandefcence, was the caufe of the electri¬
city produced by its evaporation; and that a combina^
tion was then formed, by which a new quantity of the
eletric fluid was produced. This conjecture may at
firft fight feem improbable -, but the quantity of electri¬
city produced by this experiment will aitoniffi thofe
that repeat it *, and this quantity is more furprifing, be-
caufe, if it is true, according to the fyftem of M. Vol¬
ta, that the vapours abforb, while they are forming, a
quantity of the electric fluid, there mult, therefore, be
enough developed in this experiment, for the formation
of the great quantity of vapours produced by the heated
iron, and afterwards a fufficient quantity to electrify
ftrongly the apparatus, and all thefe vapours.
5 H Thif
794 ELECT
Atmo- This experiment fliews clearly the caufe of that pro-
EkdlHcft1 eleftricity, which is unfolded in the
i—y— }' eruption of volcanoes *, as it is probable, that the water
50S in thefe, from many circumllances, acquires a much great-
Explana- er degree of heat than is given to it in our experi-
tion of the ments.
fit^ofelec- verIfy this conjefture, that it was in fome mea-
tricity ap- i"ure the combullion of the -water, or the iron, that pro¬
parent in duced the pofttive eleftricity, it was proper to try whe-
the erup- ther, by a regular moderation of the heat of the iron,
canoes '0l"P°iitive eleftricity would always be obtained. This
was eflayed in the following manner: A large iron
crucible, five inches high, four in diameter, and fix
lines thick, was heated red hot ; then infulated ; after
which, final 1 quantities of -water were thrown into it,
each projection of the water cooling more and more the
crucible j thus defending by degrees till there was only
fudicient heat to boil the water j carefully obferving, and
then deploying the eleftricity produced at each projec¬
tion. The eleftricity was always pofitive or null 5 at
the firft projections it was very lirong ; it gradually di-
minifhed to the t-welfth, when it was fcarce fenfiblc,
though always with a tendency to be pofitive.
On repeating this experiment, and varying it in dif¬
ferent ways, a remarkable circumftance was obferved :
When a finall quantity of water was thrown into the
crucible, the moment it was taken from the fire, while
it was of a pale red, approaching what is called the
white heat, no eleCfricity was obtained.
This fad feemed to have fome connection with ano¬
ther mentioned by Pvlufchenbroek, that water evaporates
more (lowly on a metal, or any other incandefcent body,
than on the fame body, heated only a finall degree a-
bove boiling water. To examine this relation, and to
find whether there was any between the periods of eva¬
poration, and the production of eleCtricity, M. Sauf-
fure made a great number of experiments, wdnch are
molt accurately defcribed in bis excellent work ; but as
the detail would be much too long to be introduced in
this article, we muft content ourielves with prefenting
the reader with the heads thereof, and a defcription of
50p the apparatus.
Experi- The apparatus confided of a pot of clay, well baked
ments on or annealed, fifteen lines thick, and four inches in dia-
tiorf012" met;er i this was infulated by a dry glafs goblet j upon
this pot wras placed the crucible, or any other heated
fubflance, On which the water was to be thrown, in
order to be reduced into vapours*, the crucible was
contiguous to a wire conneCled with an eleClrometer; a
meafure, containing 54 grains weight of diftilled wa¬
ter, was thrown upon the heated crucible ; the time
employed in the evaporation thereof was obferved by a
fecond w^atch 5 the ele&ricity produced by this evapo¬
ration tvas noted. When this meafure of wrater was re¬
duced into vapour, the eleCtricity of the apparatus wTas
deftroyed, and a frefh meafure of w*ater was thrown in¬
to the crucible *, proceeding in the fame manner till the
crucible w-as almoft cold. \
The firft experiment was with an iron crucible, from
which it was found, that Mufchenbroek was not right,
in faying that the evaporation was floweft when the iron
was hotteft ; for at the inftant it was taken from the
fire it required 19 feconds to evaporate the water, and
took more time till the third projection, when it took
35 feconds, though from th^t period it employed lefs
R 1 c I T Y. EartV.
time, or in other words, the evaporation accelerated in Atmo-
proportion as the iron cooled. fpherical
yVith refpeCt to the eleCtricity, it was at firft o, then ^e<^ncit:y«
pofitive, afterwards negative, then o, and afterwards " v
pofitive to the end of the experiment. The vapour
wras not vifible till the 'yth projection.
In the fecond experiment with the fame crucible,
though every endeavour was made ufe of to render them
as fimilar as poffible, the eleCtricity was conftantly pofitive.
.L he third experiment -was with a copper crucible *,
here alfo the eleCtricity was pofitive, and the longeft
time employed in evaporation w^as not the inftant of the
greateft heat. It w-as very curious to fee the water en¬
deavouring to gather itfelf into a globule, like mercury
on glais; to he fometimes immoveable, and then to turn
on itfelf horizontally, with great rapidity *, fometimes
throwing from fome of its points a little jet, accom¬
panied wfith a hiding noife.
The fourth experiment was with the fame crucible; the
eleClricity was at firft negative, then conftantly pofitive.
I he fifth was with a crucible of pure (liver ; a con-
fiderable time was employed here in evaporating the
fame quantity of water *, even in the inftant of the
greateft heat it took five minutes, fix feconds j the e-
leCiricity was weak, three times no eleClricity -was per¬
ceived, five times negative eleClricity was dilcovered.
In a fixth experiment with the fame crucible, a pofi¬
tive eleClricity was obtained, at the fecond projection •,
after which none of any kind was perceived.
I he feventh with the lame, gave at firft ftrong nega¬
tive eleClricity, the fecond and third projection gave a
wreak pofitive eleClricity.
I he eighth was made with a porcelain cup*, here the
evaporation was (lower at the fecond, than the firft pro¬
jection *, but from this it took longer time till it was
cold, contrary to what happened with the metals 5 the
eleClricity wras always negative.
'I he ninth and tenth experiments, with the fame cup,
produced (imilar eft’eCts.
The eleventh experiment was with fpirits of wine in
a filver crucible 5 here there was no eleClricity produ¬
ced at the twTo firft projeClions, and what was after¬
wards obtained was negative.
Twelfth experiment with ether *, here the eleClricity
was alio negative. Thefe two inflammable fluids, in
evaporating, followed the fame laws as wrater, being
diflipated at firft mod rapidly in the greateft heat, after¬
wards taking a longer and longer time before they wrere
evaporated, to a certain period, then employing lefs
time, or evaporating quicker, till the crucible wras-
nearly cold.
Now as china and filver alwTays produced negative
electricity, wdiile iron and copper have generally given
politive eleClricity, we may conclude, that eleClricity
is pofttive with thofe bodies that are capable of decom-
pofing wrater, or of being decompofed themfelves bv
their contaCl with thd water *, and negative with thofe.
which are not at all decompofed or altered.
If in the foregoing experiment, thofe fubftances
wdiich wTere fufceptible of oxidation had conftantly giv¬
en a pofitive eleClricity, and thofe which do not oxidate
had always given the negative j every thing would have
been explained by thefe principles, and they would
thence have acquired a greater degree of probability.
But the phenomena have not alwrays followed this law.
We-
Chap. IT.
ELECTRICITY.
Atmo- We have feen iron and copper fometimes give a nega-
fpherical t}ve electricity, and filver the pofitive. The firft cafe
Eiedlricity. not: |_0 account for j it is well known with
what facility iron and copper are oxidated in a brilk
fire 5 they become covered with a fcaly cruft, which is
not fufceptible of any further alteration with the fame
heat. If the bottom of the crucible acquires this crufty
coating, the drop of water placed thereon will be no
longer in contact with an oxidable fubftance j there will
be no further decompofition, no generation of the elec¬
tric fluid : the vapours, however, which are ftill formed,
will abforb a part of the fluid naturally contained in
the apparatus, and this will therefore be eledrified ne¬
gatively. If fome of the fcales Ihould be fo far de¬
tached, that the water may gain fome points of contact,
the quantity thus generated may compenfate for what
is abforbed by the vapours, and thus the electricity will
be null. If more are detached, it will fuper-abound
and be pofltive. From the fame reafons, a large mafs
of water, by attacking the iron in a greater number of
points, always gives politive eleCtricity; and hence,
alfo, a ftrong politive electricity is obtained, by throw¬
ing a piece of red-hot iron into a mafs of water.
It is not fo eafy to explain why lilver gives fometimes
a pofltive electricity, but by fuppofing it to have been
mixed with fome fubftances capable of oxidation ; and
this the more, as the white porcelain always gave ne¬
gative electricity. This fuppofttion was verifled by fome
fubfequent experiments, in which the fame fllver, when
purified, always gave a negative eleCtricity.
M. Sauflure owns himfelf incapable of explaining
why heated charcoal always gives negative eleCtricity j
unlefs it can be attributed to the promptitude with
which fo rare a fubftance lofes its heat, by the contaCt
et water.
One fact aftonilhed him, namely, that by combuf-
tion properly fo called, although it is an evaporation,
nay, the higheft degree of evaporation, he never ob¬
tained any figns of eleCtricity $ though he tried to ob¬
tain it in a variety of ways. Probably, the current
produced by the flame, difperfes and diflipates the elec¬
tricity as foon as it is formed. The cafe, however,
muft not be looked upon as general, becaufe M. Volta
obtained figns of electricity from bodies in combuftion,
by means of his condenfer.
Another Angular fact was, his not being able to ob¬
tain electricity without ebullition, though he endea¬
voured to compenfate by the quantity of iurface for the
quantity of vapours that were elevated by boiling wa¬
ter; and indeed, the fame quantity of water, if extended
over too large a furface, will not give any eleCtricity.
We {hall refume this fubject immediately, but muft
firft conclude our obfervations on the phenomena of at-
mofpherical eleftricity.
The following axioms with refpeCl to atmofpherical
eleCIricity, deduced by M. Cotte after a long courfe of
obfervations, merit attention.
x. EleCtricity manifefts itfelf oftener without ftorms
than with them.
2. It is produced more frequently by dry than by
rainy clouds.
3- ^ is more frequently pofitive than negative, ef-
pecially when occafioned by ftationary clouds.
4. The atmofphere exhibits figns of eleCtricity at all
times by night or day.
Sia
Cotte’s
axiom1'.
705
In our endeavours to explain the production of natu- Atmo-
ral eleCtricity, we have nothing more to do, than to y)1]fr.ic.al
difcover the various cireumftances of the atmolphere, ^
in which moifture is abforbed or precipitated.
It is necelfary to recolleCt the proof furnilhed by nu- Caufes of
merous experiments, that when any portion of the at-a.tmj0^^e*
mofphere is in a ftate to take up an additional quantity ”<:^te*ec"
of moifture, it is in a ftate at the fame time to take up ^I2
more eleCtric fluid ; and vice vcrfa, when it is parting ' bforption
with its water, it is at the fame time parting with itsapd preci-
eleCtric fluid. But in thefe cafes, neither the fuper-P'^1^0^
abundance nor the deficiency can produce a chjirge, pai-qcle^.
unlefs there be fome other part of the air contempo-1
raneoufly in an oppofite ftate, or in a difpofition either
to receive or give. It is, however, fcarcely poflible
that this ftrould not always happen; for our atmofphere
is, throughout its vaft dimenfions, each moment agitated
by millions of co-inftantaneous changes, and for our
purpofe, it is of no confequence where the required
change takes place. Were it New Holland, or at the
Antipodes, a connedion would be inftantly formed be¬
tween the remote but oppofite fituations, by the con¬
ducting power of the earth. ^
It is a neceffary conclufion from what we have juft Violence of
faid, that if the abforption of moifture by air, or theft°rmscoIV
copious evaporation of it from the earth, be attended 111
with a new accumulation of the fluid ; then where this
caufe operates moft powerfully, there its correfpondent
effeCt will be moft fenfible. We confequently find,
that the moft tremendous eleCIrical phenomena belong
to the countries within the tropics, or to that portion of
our atmofphere which is loaded with moifture by the
moft powerful influence of the fun’s rays. In like man¬
ner, within the limits of our own and other fimilar cli¬
mates, eleCIrical phenomena are greateft, both in force
and frequency, during the hotteft months of the year,
or during the feafon in which our atmofphere is moft
copioufly and rapidly charged, by abforbing the humi¬
dity of the ground.
In the neighbourhood of Attna and Vefuvius, during KJedlncal
the period of their volcanic fury, furfaces, covering theaPPearanc*
dimenfions of feveral fquare leagues, are fometimesot voIca'
fcorched with red-hot lava, and every atom of their ‘ *
moifture is rapidly diflipated. At the fame time the
furrounding air is heated to a vaft extent, and in this
ftate fwallows up an immenfe quantity of aqueous va¬
pour ; but contemporaneoufly with the operation of
thefe powers, according to the reports of all natural
hiftorians, an immenfe quantity of the eleCtric fluid is ac¬
cumulated and difcharged. 515
Again, a dry wind palling over a moift foil is ano-Storms pe¬
ttier modification of the caufe we are applying ; it pro-^u^?Jtot^e
duces a copious and rapid folution of the aqueous par-
tides, and its confequent alteration of attractive force.
Let us for inftance, fuppofe a wind, which had pafied
over the deferts of Arabia, or that had been torrefied in
its palfage over a large extent of burning fands, to come
in contaCt with a fimilar extent of marlhy foil, or of any
furface well drenched with water, a moft abundant eva¬
poration would neceffarily take place, and with it an
immenfe accumulation of the eleCtric fluid. But fub-
fequently, in cafe any power operated, which would
take away the aqueous particles thus diffolved, and of
courfe alter the degree of attractive force by which
the collected eleCtric fluid is.Jiifpended, we ftiould find
5 H 2 that
795 ELECT
Atm.o- that the moft dreadful thunder-ftorms would take place.
Eledlrici^1 is real,y thc cafe ? f°r there is fcarcely a region in
c, 'y' the valt circle furrounding the immeafurable fands of
Africa, which is not remarkable for florins and tempefts.
On the fide of Abyflinia, when the warm winds that
have paffed over the neighbouring deferts are condenfed
on its mountains, thofe deluges are colledled, which
form the inundations of the Nile.
On the coaft of Guinea, the harmattan, which is a
current of air fo dry, as to wither and pulverize, by a
complete abforption of all its juices, every fubflance
that occurs in its paffage, is no fboner mixed with that
body of air which is cooled by the ocean, than it forms
molt terrific hurricanes of wind and lightning that are
defcribed by navigators. Along the Syrian regions,
we learn from facred authority, that the ftorms gather
with fuch rapidity, that a cloud, which this inflant
might be covered with the hand, is within the interval
of a few minutes, charged with water adequate to the
inundation of a whole country.
-Che thunder that attended thefe impetuous ftorms,
provoked the fublimeft expreflions of their poets. In¬
deed, whenever their minds attempt the defcription of
celeftial greatnefs, or the hidden and overwhelming ap¬
proach of divine power in its triumph, or in its fury,
they have recourfe for imagery to thofe thunder-clouds,
which they juftly reprefented as extinguifliing the light
of the fun, and as involving the world in a few inftants
in the darknefs of midnight.
Application Having fpecified the two moft general caufes of eva-
ofthe vari- poration on the furface of this earth, let us now attend
^ecLita ^ to the poflible changes of the atmofphere, when by the
operation of either, or both, it is charged with the elec¬
tric fluid. All thefe changes are but different degrees
of the fame effe£l, viz. the condenfation of moilture,
and this condenfation is in every cafe produced by an
^ alteration of temperature, which may proceed,
Mixture of I* From a mixture, or even the contaft, of a colder
of a colder with a warmer air. When the fmalleft clouds are form-
with a ed by fuch a mixture, an ele&rical charge takes place,
warmer air. tjlat one part 0£ t]ie cioucj has more> ancl ^ other
lefs, than its natural lhare. Fogs, dews, and the flight-
eft change of clear for hazy weather, commonly arife
from a warmer atmofphere coming in contaft with one
of a lower temperature ; but even thefe trifling degrees
of condenfation are always followed by figns of eledlri-
* Vide
JicaJ on
city
In this country, from its infular fituation, which ex-
fpontaneous p0fes jt to the perpetual influence of varying winds, the
EUflncity. ajr changes its appearances often many times in one day.
But there is no degree of thick cloudinefs or perfebl
clearnefs, of fcattered clouds fucceeding embodied maf-
fes of clouds, of fmall rain increaling to heavy, or vice
verfo, that is not attended with changes in the expref-
fions of the elevated conductor, which never fails to
vary with all the atmofpheric condenfations and rarefac¬
tions that take place.
It is, however, obvious that the effeft muft be in
proportion to the quantity and rapidity of the condenfa¬
tion. When, therefore, any body of air has been for
a long time fufpended over a furface of ground previ-
oully drenched with fhowTers, and at the fame time ex-
pofed to the violence of the fun’s rays, a change in the
direftion of the wand, or fuch a change in the weight
of the air as mixes the upper with the lower regions
R I C I T Y. Part V.
of the air, is almoft always attended with a thunder- Atmo-
ftorm. fpherical
In tropical climates, for months together, fcarcely aE“'<^ Clty',
day paffes, in wdiich the calm atmofphere is not loaded
by fucceflive additions of moifture, till at laft, it be¬
comes the refervoir of vaft rivers and lakes, and of all
the moifture that is ipread over whole continents. But
when this drought has reached its crifis, the fun croffes
the line, the wand takes a new direction, a colder air
mixes with that which is thus charged with vapours,
and the condenfation becomes fo copious, as to inundate
all the fubjacent country 5 but the deluge is not more
deftiublive than its attendant ftorm } for, according to
the reports of fpeftators, our imaginations, confined to
the proceedings of nature in this frozen region, have
no images from which any fuch comparifon can be
made, as will communicate the leaft idea of the thunder
attending a tropical hurricane.
The caufe which we are now applying to the expla¬
nation of thefe natural appearances, will furnifh us with
an ealy folution of a difficulty which has oppreffed feveral
theories of eleftricity, namely, that rapid generation
and increafe of the eleblric fluid wffiich takes, place in
fome thunder-ftorms. Even in this country, the fuc-
ceflion of flaflies is fometimes fo quick, that one hun¬
dred and twenty have been known to follow each other
in a minute. In Afia, this celerity of accumulation
and difcharge was lo great, that Homer ufes it as part
of a fimile, by wThich he paints the quick repetition
of Agamemnon’s fighs and pantings in an hour of dif-
trefs.
It may be alked, if each diftindt cloud is loaded with
a diftinft charge, and if each flafti is a feparate dif¬
charge of fuch a cloud, what is there, in our know¬
ledge of natural powers, that wall account for an in¬
numerable repetition of thefe accumulations and dif-
charges within a very ftiort fpace of time, more efpeci-
ally when each of them is connected in our minds with
the neceflity of a diftindl part of that time for its pro-
cefs ? In other words, do we know of any caufe that is
adequate to the filling and emptying of the fame por¬
tion of air every inftant, for hours together ?
On a hot fummer’s day it not unfrequently happens,
that a fine blue Iky will, within five feconds, be chan¬
ged into one mafs of clouds. If the caufe which pro¬
duced fo great an effedt, were fuppofed to be doubled
in its power of condenfation, the degree of eledtricity
Ihown by the elevated condudlcr would be rather more
than doubled, and its figns wTould be much ftronger
than in a common ftorm ; w?e may hence conclude, that
the whole mafs which might be thus formed in-five fe¬
conds, wrculd be loaded fo as to have every pait of it
at the difcharging height ) but the mafs might confift
of hundreds of diftincl clouds all in the fame ftate, and
confequently adequate to the produdlion of feveral hun¬
dred flalhes within a minute.
The collapfe of aqueous particles, wftfieh wmuld ne-
ceffaiily follow fueh a rapid lucceffion of difcharges a&
have been now proved to be poflible, vrould produce a
partial vacuum of great extent, and on all fides the
heavier air would rulh into it, and the upper and cold¬
er regions would prefs downwards, and by their con-
denfing temperatures, would renovate all the accumu¬
lations and difcharges which have been already defcrib¬
ed : a fecond collapfe would follow a fecond feries of
thunder-ftrokes*
Chap. II.
ELECT
Atmo-
fpherical
Eietflricity.
jiS
Heated air
coming in
contact
With the
cold earth.
S.I9 .
Sudden in-
terruntion
of the fm ’i
influence.
thunder-ftrokes, and a partial vacuum additional to
the former 5 a freih portion of warm air would again
rufh in from all quarters, and a frefh mixture of cold
air from the upper regions. It is fcarcely neceffary to
fhow that this repetition of condenfations may continue
for hours, or till the air, which rufhes in laterally, be¬
comes of fuch a temperature, that its mixture with the
colder air will not produce the condenfations adequate
to the collection of that quantity of eleftric fluid which
is neceffary for a difcharge.
From this explanation, it is obvious that a central
point muff exilt, at which the violence of every florm
begins, and from which it is fpread in all direftions.
A hurricane in the Weft Indies, though ruinous to
many, is generally the diftinguiftiing calamity of one
iiland, at wdrich alone the wind is defcribed as blowing
from every point of the compafs 5 while in every other
iftand, it is reprefented as bearing down deciiively from
one quarter.
2. The precipitation of aqueous particles when fuf-
pended by heat in air, is frequently the confequence of
the loaded atmofphere’s coming in conta£f with portions
of the earth that are colder than itfelf. Such, particu¬
larly, are the fummits of mountains, whole effect is
great in proportion to the degree of their cold and the
extent of their furface. It is, however, certain that
condenfations, when thus produced, are invariably at¬
tended by thunder-ftorms.
The uproar, and the fplendour of the innumerable
lightnings, which dart through all the entangled cir¬
cuits of an abyfs of thunder-clouds, are the immutable
attributes of grandeur which belong to the Cordilleras;
for they dam up, as it were, an immenfe flow of air,
which is almoft faturated with moifture by palling over
feveral thoufand leagues of land, expofed to the fury of
a tropical fun.
In fummer, the north-wefterly winds that pafs over
France, are always condenfed by the Alps •, and in the
night, during fuch a ftate of the atmofphere, to all thofe
who live along the Saone and the upper part of the
Rhone, thefe mountains are always brightened by elec¬
trical flafhes and corrufcations.
All ridges or chains of very high grounds, efpecially
thofe which terminate extenfive plains lying in the di-
redlion of their moft common winds, are perpetually
beclouded ; and with a good condudlor, fixed on their
fummit, we Ihould find that the figns of eledtricity were
as conftant as the condenfations by which they are en¬
veloped. But in proportion to the coldnefs, fo is the
fubfequent change of temperature on the eminences di-
minilhed, and the eleftrical effedt dependant on that
change- It hence happens, that there are countries in
the northern parts of Europe, the gloom of whofe mills
is never difperled by a thunder-ftorm, excepting in the
hotteft feafon of fnmmer.
3. When the fun, by directing its rays with force
and abundance upon the earth for any length of time,
has produced a conftderable evaporation, the mere in¬
terruption of its influence will be attended with a dif¬
charge of the eledlric fluid ; for the great fource of
change in our atmofphere is the ready influence of its
upper regions, which are cold, on its lower regions when
warmed ; and any caufe which mixes thefe together,
muft bring on a condenfation of aqueous vapour. This
R I C 1 T Y. 797
mixture, however, takes place on the mere approach of A tmo-
night, as is evident from the change of temperature ex-
preffed by the thermometer, and the ufual fall of the i' 11
dews 5 we confequently find, that as night comes on,
the figns of electricity always increafe. When the
weather is tolerably fettled, or fuch that no other caufe
is aClive than that proceeding from the change of day
for night, or night for day j then the figns of eleClrici-
ty gradually decreafe from twelve o’clock at night till
fix in the morning 5 from this hour till nine, they gra¬
dually increafe, when they become exceedingly weak,
and continue fo till four in the afternoon : the increafe
at this time recommences, and is very decifive in its
appearance till about two hours after funfet, when it
becomes ftationary, and remains in this ftate, or de-
creafing, fo as fcarcely to be fenfible, till the mor¬
ning *. *
The caufe, whofe operation we have now inveftigated out
in the production of its moft feeble effeCts, may be eafi-^
ly applied to many other caufes, in which fimilar, but
greater powers are difplayed by nature. Let us fup-
•pofe, that on a wide furface of ground, previoufly warm¬
ed by the fun, copious fhowers of rain had fallen, fol¬
lowed by a return of the fun’s influence ; in this cafe,
the evaporation is neceffarily very rapid, and the figns
of eleClricity expreffed by an elevated conductor are
very ftrong.
When a copious production of eleCtric fluid has at¬
tended a copious evaporation continued for feveral fuc-
ceflive hours, a thunder-ftorm, or fome linking eleCtri-
cal appearance will come on with the approach of night} ■
for unlefs the barometer ftiould fuddenly rife, the con¬
denfation attending the evening’s cold muft be very con-
fiderable, and its ufual confequences proportionally
great. Such a day as wTe have juft defcribed, is ufually
followed by a violent thunder-ftorm. Indeed, there is
fcarcely an inftance in which a moift ground, operated
on for fome hours by a clear fun, provided the wind
continues to blow from the fouth-weft or weft, is not
attended the following night by the appearance of fal¬
ling ftars, flalhes of lightning, or the Aurora Borea-
hs* ' ' j20
We have alluded to the connection of winds with EfFe<f(: of'
the phenomena of atmofpherical eleCtricity. The in- ^■nc*)s on .
fluence of winds muft depend on various circumftances
in fome cafes, they will tend to dimimlh eleCtrical ap-atmofphtre.
pearances, and in others, they may altogether deftroy
them. The current of air which proceeds from a mix¬
ture of two winds of different temperatures, is the ef¬
fect of a condenfation of vapour, that may be fucceed-
ed by the moft violent ftorms. But if there Ihould be
two neighbouring regions, in one of which, the rays of
the fun Ihould co-operate with the moifture of the
ground, in producing eleCtricity, while in the other
there ihould prevail a condenfation favourable to the
difcharge of the eleCtric fluid } a current of air would
be produced that would aft like a communicating rod
between two oppofite eleCtrified furfaces, would ex¬
change the lituations of the charged bodies^ and would
confequently caufe the new fituation to counteract the
effeCts produced in the laft. This effeCt would be more
fenfible in proportion as the exchange has been more
rapid, and accordingly we find, that during high winds, * Morgan '1 *
the electricity of the atmofphere is very fmall *. Leftures,
Chap.vo •Ur
79*
Atmo-
fpherical
JElesftricity.
ELECT
Chap. III. Of the Aurora Borealis.
Most of the luminous appearances in the atmofphere
have of late been attributed to ele&ricity. Of thefe we
In all at prefent only conlider the Aurora Borealis, or
Northern Lights, referving the account of other meteors
Phenomena^ ^ art^e METEOROLOGY.
of the aim)- .^he aui‘ora borealis is ufually of a reddilh colour, in-
ra borealis. chning to yellow, fending out frequent corufcations of
pale light, which feem to rife from the horizon in a py¬
ramidal undulating form, {hooting with great velocity
towards the zenith. This light fometimes appears re-
. markably red, as it happened December 5. 1737.
The aurora borealis appears frequently in the form of
an arch ; chiefly in fpring and autumn, after a dry
year. This arch is partly bright, partly dark, but ge¬
nerally tranfparent ; and no change is found to be pro¬
duced by it on the rays of light which pafs through it.
It fometimes produces a rainbow.
This kind of meteor, which becomes more uncom¬
mon as we approach towards the equator, is almoft
conftant during the long winter of the polar regions,
and appears there with the greateft luftre.
In the Shetland illes, the merry dancers, as the nor¬
thern lights are there called, are the conftant atten¬
dants of clear evenings, and afford great relief amid
the gloom of the long winter nights. They commonly
appear at twilight, near the horizon, of a dim colour,
approaching to yellow } fometimes continuing in that
ftate for feveral hours, without any perceptible' motion ;
and afterwards breaking out into ilreams of Ifronger
light, fpreading into columns, and changing {lowly in¬
to numberlefs different fhapes, and varying in colour
xrom all the tints of yellow, to the moff obfcure ruflet
brown. They often cover the whole hemifphere, then
exhibiting the moil brilliant appearance. Their motions
'p.t this time are exceedingly quick, and they aftonilh
the fpeftator with the rapid change of their form. They
break out in places where none were feen before, ikim
brilkly along the heavens, are fuddenly extinguiflied,
and are fucceeded by a uniform dulky tradl. This
again is brilliantly illuminated in the fame manner, and
as iuddenly becomes a dark fpace. In fome nights,
they a flume the appearance of large columns, on one
fide of the deepelt yellow, and on the other gradually
changing, till it becomes undiftinguifliable from the
iky. They have generally a ftrcng tremulous motion
from one end to the other, continuing till the whole
vaniflies. As for us, who fee only the extremities of
thefe phenomena, we can have but a faint idea of their
fplendour and motions. They differ in colour accord¬
ing to the hate of the atmofphere, and fometimes af-
fuming the colour of blood, they make a dreadful ap¬
pearance. 1 he ruftic fages who oblerve them become
prophetic, and terrify the fpe&ators with alarm of war,
peftilence, and famine ; nor indeed were thefe fuperfti-
tious prefages peculiar to the northern iflands : appear¬
ances of a fimilar nature are of an ancient date 5 and
they were diftinguilhed by the appellations of phafmata,
trabes, and bolides, according to their forms and co¬
lours. In old times they were either more rare or lefs
frequently noticed j but when they occurred, they were
R I C I T Y. * Part v.
fuppofed to portend great events, and the timid imagi- Atmo-
nation formed of them aerial conflidls. fpherical
In the northern latitudes of Sweden and Lapland, Elearieity;
the aurora borealis is not only an objedl of plealing cu- v~
riofity from the Angular beauty of its appearance, but
is extremely ufeful in affording to travellers, by its ai¬
med conftant effulgence, a very brilliant light. In
Hudfon’s bay, it is faid to poffefs a variegated fplendour,
equalling that of the full moon. “ In the north-eaf-
tein parts of Siberia,” fays Gmelin, u thefe northern
lights are obferved to begin with Angle bright pillars
riling in tne north, and almoft at the lame time in the
north-eaft, which gradually increaftng, comprehend a
large fpace ^ of the heavens, rulh about , from place to
place with incredible velocity, and Anally almoft cover
the whole fey up to the zenith, and produce an appear¬
ance as if a vaft tent was Ipread in the heavens, glitter¬
ing with gold, rubies, and fapphire. A more beautiful
fpeflacle cannot be painted ; but whoever Ihould fee
luch a northern light for the Aril time, could not behold it
without terror. lor however Ane the illumination may
be, it is attended, as 1 have learned, with fuch a hil-
Ang, cracking, and rulhing noife through the air, as if
the largeft Areworks were playing off. To deferibe
what they then hear, they make ufe of the expreffion
fpolochi chodjat, i. e. “ the raging hoft is pafting.” The
hunters who purfue the white and blue foxes in the con-
Anes of the Icy fea, are often overtaken with thefe
northern lights. Their dogs are then fo frightened,
that they will not move, but lie obftinately on the
ground till the noife has pafied. Commonly clear and
calm wxather follows this kind of northern lights. I
have heard this account, not from one perfon only, but
conArmed by the teftimony of many who have fpent *
part ^ of fever hi years in thefe very northern regions, and
inhabited different countries from the Yenifei to the
Lena j 10 that no doubt of its truth can remain. This
feems, indeed, to be the birthplace of the aurora bo¬
realis * ”
Vf • - , . * Phil,
1 ms account ot the noiies attending the aurora bo- Tran/.
reahs, allowing for fome degree of exaggeration, hasv°klxxiv.
been corroborated by other teftimonies. P*
Similar appearances have likewafe been obferved to- Aurora
w’ards the fouth pole, and are therefore called ««ror<rauftra]ii
atiflrales. J he belt account of thefe is given by Mr
For lie r, who in his voyage round the world with
Captain Cook, fays that he obferved them in high
fouthern latitudes, though attended with phenomena
fomewhat different from thofe obferved here. “ On
February 17. 1773, in fouth lat. 58°, a beautiful pheno¬
menon (he fays), was obferved during the preceding
night, which appeared again this and feveral following
nights. It conAfted of long columns of a clear white
light, {hooting up from the horizon to the eaftward,
almoft to the zenith, and gradually fpreading on the
whole fouthern part of the Iky. Thefe columns w^ere
fometimes bent ftdewrays at their upper extremities, and
though in moll refpedls Amilar to the northern lights
(aurora borealis) of our hemifphere, yet differed from
them in being always of a whitifli colour, wTereas ours
aflume various tints, efpecially thofe of a Aery and purple
hue. The fley was generally clear when they appear¬
ed, and the air ftiarp and cold, the thermometer Hand¬
ing at the freezing point.”
The
Chap.
III. ELECT
At mo- The periods of the appearances of the aurora borealis
fpherical are very inconftant. In fome years they occur very
Eleftiic.ty. frequently, and in others they are more rare ; and it
has been obferved that they are more common about
the time of the equinoxes than at other leafons.
Dr Halley has given us a lort of chronological
hiftory o£ the appearances which may be ranked under
the aurora borealis ; but for his account of the indivi¬
dual cafes we mult refer to his paper in the Philofophi-
cal Tranfaftions Abridged, vol. iv.
The particular part of the atmofphere in which thefe
appearances take place, or the height above the earth
to which they extend, is by n* means certain 5 various
philofophers have attempted to afcertain the height of
various aurorte boreales by trigonometrical calculation *,
fome have eftimated them at a few hundreds, others at
fome thoufands of miles above the earth j but the refults
of their admeafurements are fo contradidlory, that they
r ^ cannot be relied on.
Aurora u Several of the mod celebrated inquirers into nature
attributed have given their authority to fome of the mod extrava-
by fome to gant theories, in attempting to aflign its proper caufe
polar fires. to the aurora borealis. Their imaginations have
kindled bonfires in the poles of the earth, and they
have reprefented the northern lights as the effedfs of
flames, to which thofe lights have fcarcely any fimilari-
ty, and from which they are diflinguilhed by numberlefs
diverfities.
“ The falt-pits of the north were at one time re¬
garded as emitting a luminous effluvium from their en¬
trails, copious enough to pervade the whole of our
northern atmofphere. The difeoveries of eleflricians
have configned all thefe reveries to a lhade, whence
* Morganswould never return to excite the wonder of mo-
LeSiuret, dern philofophers, if the authors of them had not
vol. ii. brought forth other produdlions, whofe merits have
P* 335* made even their miflakes immortal*.'”
Evidence evidence which we have for confidering the
for its elec- aurora borealis as an effedt of eledlricity, chiefly confifls
trical ori- of the following arguments.
2m* 1. If lightning be an effect of eledlricity, the fame
caufe mud, at a certain height in the atmolphere, pro¬
duce fuch an appearance as is exhibited by the aurora
borealis. The paffage of the eledtric matter through air
rarefied to a certain degree, is attended with all the undu¬
lating corufcations of this meteor. Indeed there is
Icarcely a Angle circumdance attending the paffage of
a fpark or a charge through an exhaufled tube, that
does not bear a refemblance to fomething obferved in
the northern lights. The fame peculiar motion, the
fame variety of colour, the fame rapid alternations of
flalhes, occur both in the experiment, and in the natural
phenomenon 5 the dreams of light in both are vivid
and pointed; and if, in the experiment, the exhaudion
has been properly managed, fome parts of the light
wall be marked with that reddilh tinge, which in the
aurora borealis has fo often druck the vulgar mind
with terror and condernation. The experiments to
which we particularly allude are thofe of the conduEling
glafs tube, the luminous conductor and the aurora bore¬
alis deferibed in N* 188—190.
2. The flriking didance of a charge of eleftric fluid
paflmg through the air, increafes according to the rare-
faflion of that medium. If, therefore, two clouds in
oppofite dates of eleflricity have no other circuit, it is.
R I c I T Y.
799
probable that they will be difeharged through the high- Atmo-
er regions of the atmofphere, more efpecially if they
are at luch an elevation, as renders their communication 'fc ’1C1
with the earth impracticable.
3. The fame caufes which tend to produce fuch an
accumulation of eleClricity in the atmofphere as will
bring on a thunder-dorm, have been found, in certain
feafons, and in the more northern climates, to be at¬
tended with an aurora borealis.
It mud be confeffed, however, that Mr Brook and
PTr Bennet, in their obfervations on the eleClricity of
the atmolphere during an aurora borealis, could obferve
no particular figns ot increafed eleClricity, more than
■would have occurred in a ferene Iky without any luch
appearance.
4. A magnetic needle commonly appears a little
dilfurbed during a flrong aurora borealis.
We have already hinted at the connexion between
magnetifm and eleffricity, and we fliall fully illuflrate
this in the article Magnetism. Till this conneClion
is fully explained, the force of this lad argument can
fcarcely be feen. ^
A confiderable difficulty attends even the n*od re- Theory of
ceived theories of the aurora borealis, viz. the light thefe ap-
appearing always to llrike from the poles towards the l)earances*"
equator, rather than in the contrary direClion. Per¬
haps this may be explained in the following manner.
We lhall affume the three following axioms.
1. 2 hat all electrics when conjidcrab/ij heated, become
condudlors of eledlricity.
2. 7 hat, e converfo, non-elcBrics when JuhjeBed to vio¬
lent degrees of cold, ought to become elclirics.
3. 1 hat cold tnuf alfo increafe the elcdlric powers of
fuch fubjlances as are already electric.
The air, all round the globe, at a certain height
above its furfacev is found to be exceedingly cold, and,
as far as experiments have yet determined, exceedingly
electrical. The inferior parts of the atmofphere be¬
tween the tropics, are violently heated during the day¬
time, by the reflection of the fun’s rays from the earth.
Such air will, therefore, be a kind of conductor, and
much more readily part w-ith its electricity to the clouds
and vapours floating in it, than the colder air towards
the north and fouth poles. Hence the prodigious ap¬
pearances of eleftricity in thefe regions, fliewing itfelf
in thunder and other tempefts of the molt terrible kind.
Immenfe quantities of the eleftric fluid are thus com¬
municated to the earth ; and the inferior wrarm atmo*-
Iphere having once exhaulted itfelf, muft neceffarily be
recruited from the upper and colder region. This be¬
comes very probable from what the French mathema¬
ticians obferved when on the top of one of the Andes.-
ihey were often involved in clouds, which, finding
down into the warmer air, appeared there to be highly
eledlrified, and difeharged themfelves in violent tempefts
of thunder and lightning j while in the mean time, on
the top of the mountain, they enjoyed a calm and ferene
fky. In the temperate and frigid zones, the inferior
parts of the atmofphere, never being fo ftrongly heated,
do not part with their eledhicity fo eafily as in the tor¬
rid zone, and confequently do not require fuch recruits
from the upper fregionsj but notwithftanding the dif¬
ference of heat obferved in different parts of the earth
near the furface, it is very probable that at confiderable
heights the degrees of cold are nearly equal all round
tha
goo ELECTRICITY. Part VI.
Atmo- the globe. Were there a like equality in the heat of
fpherical under part, there could never be any confiderable
. c ^1C1 y~, lofs of equilibrium in the eleftricity of the atmofphere j
but as the hot air of the torrid zone is perpetually
bringing down vaft quantities of electric matter from
the cold air that lies above it; and as the inferior parts
of the atmofphere lying towards the north and fouth
poles do not conduft in any great degree *, it thence
follows, that the upper parts of the atmofphere lying
over the torrid zone will continually require a fupply
from the northern and fouthern regions. This eafily
Ihews the neceflity of an electric current in the upper
parts of the atmofphere from each pole towards the
equator j and thus we are alfo fumifhed with a reafon
why the aurora borealis appears more frequently in
winter than in fummer j namely, becaufe at that time
the eledtric power of the inferior atmofphere is greater
on account of the cold than in fummer j and confe-
quently the abundant eledfricity of the upper regions
mull go almoft wholly off to the equatorial parts, it
being impoffible for it to get down to the earth ; hence
alfo the aurora borealis appears very frequent and bright
in the frigid zones, the degree of cold in the upper
and under regions of the atmofphere being much more
nearly equal in thefe parts than in any other. In fome
parts of Siberia particularly, this meteor appears con-
ftantly from Odfober to Chriltmas, and its corufcations
are faid to be very terrifying. Travellers agree that
here the aurora borealis appears in its greateil perfec¬
tion } and it is to be remarked, that Siberia is one of
the coldeit countries in the world. In confirmation of
this, it may alfo be obferved, that from the experiments
hitherto made with the kite, the air appears confider-
ably more eledtrical in winter than in fummer, though
the clouds are known to be often moll violently elec¬
trified in the fummer time j a proof, that the eledlricity
naturally belonging to the air, is in fummer much more
powerfully drawn off by the clouds than in winter, ow¬
ing to the excels of heat.
A confiderable difficulty, however, Hill remains from
the upright pofition which the ftreams of the aurora Atmo-
borealis are generally fuppofed to have j whereas, ac- fpherical
cording to our hypothefis, they ought rather to run di-'F1^1'10^^
redlly from north to fouth. Dr Halley anfwered this
difficulty by fuppofing his magnetic effluvia, (to which
he attributed this phenomenon), to pafs from pole to
pole in arches of great circles, arifing to a great height
above the earth, and confequently darting from the
places whence they arofe like the radii of a circle j in
which cafe, being fet off in a diredlion nearly perpendi¬
cular to the furface of the earth, they mull neceffarily
appear eredl to thofe who fee them from any part of
the furface, as is demonllrated by mathematicans. It
is alfo reafonable to think that they will take this di¬
redlion rather than any other, on account of their meet¬
ing with lels relillance in the very high regions of the
air than in fuch as are lower.
But the greateil difficulty Hill remains j for we have
fuppofed the equilibrium of the atmofphere to be broken
in the daytime, and reltored only at night j wffiereas,
confidering the immenfe velocity with which the elec¬
tric lluid moves, the equilibrium ought to be rellored
in all parts almoil inltantaneoully j yet the aurora bore¬
alis never appears except in the night, although its
brightnefs is fuch as mull fometimes make it vifihk to
us did it really exill in the day time.
In anfwer to this it mull be obferved, that though
the paffage of eledlricity through a good condudlor is
almoil inilantaneous, yet through a bad condudlor it
takes fome time in palling. As our atmofphere, there¬
fore, unlefs very violently heated, is but a bad conduc¬
tor of eledlricity 5 though the equilibrium in it is brok¬
en, it can by no means be inilantaneoully rellored.
Add to this, that as it is the adlion of the fun wffiich
breaks the equilibrium, fo the fame adlion, extending
over half the globe, prevents almoll any attempt to re-
llore it till night, when llaffies arife from various parts
of the atmofphere, gradually extending themfelves with
a variety of undulations towards the equator.
PART VI.
OF THE EFFECTS OF ELECTRICITY ON VEGETABLE LIFE.
$26
Experi¬
ments on
vegetation
by
527
Mr Maim-
bray.
Prie/lley’s
ffjtory.
Part viii.
fe£t. 4.
S27
Abb 6 Nol¬
ift.
IT has been much difputed whether eledlricity pro¬
duces any effedls on vegetables ; and the experiments
that have been made with the view of afcertaining this
point are moll contradidlory.
The firll eledlrician who feems to have attended to
this fubjedl of inquiry wTas Mr Maimbray of Edinburgh,
who, in the year 1746, eledlrilied two myrtles during
the wffiole month of Odloher (L e. we fuppofe, for
fome hours every day). The confequence was, that in
the following fummer, thefe eledlrified myrtles put forth
buds and bloffoms fooner than their neighbours who
had been left to nature *.
Mr Maimbray was foon followed by the Abbd Nol-
let, wffio made fome comparative experiments on the
germination of feeds under fimilar circumllances, ex¬
cept that one pot was eledlrified three or four hours
every day for fifteen days. The refult of thefe expel i- N°lkt
ments was fimilar to that of Mr Maimbray’s f. '*
Similar experiments wTere made by M. Achard of j^_5Acjiar<]<.
Berlin, and feveral other philofophers, but Hill with the 529
fame refult ; till Dr Ingenhoufz inllituted a very com- Dr Ingcu-
plete fet of experiments on the eledlrification of plants,
w'hich were communicated to the world through the
medium of Rozier’s Journal, at firll by M. Swankhardt,
and aftemards by Dr Ingenhoufz himfelf, in confe¬
quence of fome fevere animadverfions which the com¬
munication of M. Swankhardt had called from M.
Duvemier. By thefe experiments the faith of philofo¬
phers with refpedl to the effedl of eledlricity on vegeta¬
tion w-as llaggered, as they were attended with refults
very oppolite to thofe ,of Maimbray, Nollet and A-
chard,
Experiment;*
may and
1’abbe Or-
moy.
* Morgan s
LeSiuret,
vol. ii.
53
Ion.
532
Eledlro-
Vegetome-
ter dffcri-
%ed-.
Part VI. ELECT
Effects of Experiments have alfo been made by Dr Carmoy
Electricity an(j tile abbg D’Ormoy, rather more favourable to the
®u opinion j but the manner in which the electricity
» v ' ' was applied appears very equivocal, as it is found that
530 even fliocks do not pafs through the body of the plant,
by Dr Car. but merely OVer its furface
But the moft complete fet of experiments on this
fubjeft has been made by the Abb6 Bertholon, and
thefe we (hall give more in detail.
“ In the firft place (fays the Abbe), there is continu¬
ally and everywhere diffufed in the atmofphere (particu-
By the ab- larty the upper regions) a confiderable quantity of
be Bertho- the eleftric fluid.
“ This principle being granted : in order to reme¬
dy the deficiency of eledlric fluid which i# fuppofed hurt¬
ful to vegetation, we mud ere£t in the fpot which we
want to fecundate the following new apparatus, which
has had all poilibie fuccefs, and which I (hall call by
the name of the eieSlro'-vegetometer. This machine is
as Ample in its conitrudtion as efficacious in its manner
of adling 5 and I doubt not but it will be adopted by
all thofe who are fufficiently inftructed in the great
principles of nature*
“ This apparatus is coropofed of a mad AB, fig. 131,
or a long pole thrud jud fo far into the earth as to dand
firm and be able to refid the winds. That part of the
mad which is to be in the earth mud be well dried at
the fire j and you mud take care to lay on it a good
coat of pitch and tar after taking it from the fire, that
the refinous particles may enter more deeply into the
pores of the wood, which will then be dilated, at the
fame time that its humidity will be expelled by the
heat. Care mud likewife be taken to throw around
that part fixed in the earth a certain quantity of coal
dud, or rather a thick layer of good cement, and to
build befides a bafe of mafon-work of a thicknefs and
depth proportionable to the elevation of the indrument,
fo as to keep it durable and folid. As to the portion of
it above the ground, it will be futficient to put upon
it fome coats of oil paint, except one choofes rather to
lay on a coat of bitumen the whole length of the piece.
“ At the top of the mad there is to be put an iron
confole or fupport C j whofe pointed extremity you
are to fix in the upper end of the mad, while the other
extremity is to terminate in a ring, in order to receive
the hollow glafs tube which is feen at D, and in which
there is to be glued an iron rod rifing with the point E.
This rod, thus pointed at its upper extremity, is com¬
pletely infulated, by reafon of its keeping a ilrong
hold of a thick glafs tube, which is filled with a quan*
tity of bituminous matter, mixed with charcoal, brick-
dud, and glafs-powder j all together forming a fuf¬
ficiently good and drong cement for the objedl in view7.
To prevent rain wetting the glafs tube, care mud be
Taken to folder to the rod E a funnel of wdute-iroh \
which confequently is entirely infulated. From the
lower extremity of the rod E hangs a chain G, which
enters into a fecond glafs tube H, fupported by the
prop I. The lower end of the above-mentioned chain
•reds upon a circular piece of iron ware, which forms a
part of the horizontal conductor KLMN. In L is a
breaker w7ith a turning joint or hinge, in order to move
to the right or left the iron rod LMN j there is like¬
wife another in £>, to give dill greater effedl to the
'circular movement. O and P are two funports termi-
Vol. VII. Part II.
R 1 C I T Y. 8ot
Hating in a fork, where there is fixed a (liken cord Effedls ot
tightly dretched, in order to infulate the horizontal
condudlor : in N are feveral very (harp iron points. tj0I(
“ In fig. 132. you fee an apparatus in the main like 
the former, but with fome difference in the conftrudlion. ^,,
At the upper extremity of the mail a b there is bored Another
a hole into wrhich enters a wooden cylinder c, w'hich form of this
has been carefully dried before a great fire, in order to111^111112111,
extradt its humidity, dilate its pores, and faturate it
with tar, pitch, or turpentine, applied at repeated
intervals. The more heat the wood and bituminous
matter receives, the more the fubdance penetrates, and
the infulation will be the more complete. It is more¬
over proper to befmear the circumference of the little
cylinder with a pretty thick coat of bitumen. This
preparation being made, we next infert the cylinder c in ¬
to the hole b of the mail j and it is eafy to join togethet
thefe two wmoden pieces in the moil perfect manner.
“ At the upper extremity of the cylinder c we ilrong-
ly attach an iron rod gf; wiiich, indead of one, is
terminated by feveral (harp points, all of gilded iron.
In e you fee a branch of iron refembling the arm of
an iron crow7, from whence hangs an iron chain h /,
at the end of which there is hooked a piece of iron re¬
fembling a mafon’s fquare, and ending in a fork. The
piece of iron /is a ring with a handle entering a little
into the glafs tube m filled with madich, in the fame
manner as does the iron rod n. The condudlor p 9
is to be confidered as an additional piece to adt in that
marked p. There are likewife put iron fpikes in q :
the fupport s refembles thofe of O and P in the former
figure. In this new machine you can lengthen or
(horten the horizontal condudlor as you pleafe j and as
the iron ring / turns freely in a circular gorge made in
the mad, the condudlor is enabled to defcribe the entire
area of a circle. ^
“ The conilrudlion of this eleBfo-vegetometer once w7ell Effects of
underllood, it w7ill be eafy for us to conceive its eftedts. thefe inftra*
The eledlricity which prevails in the aerial regions wTillmerrt,s*
foon be drawn down by the elevated points of the upper
extremity.
“ The eledlric matter brought down by the point E,
or by thofe marked fff, will be neceffarily tranfmitted
both by the rod and chain ; becaufe the infulation
produced at the upper extremity of the mad complete¬
ly prevents its communication with the timber. The
eledlric fluid paffes from the chain to the horizontal
condudlor KM. or « 0 : it then efcapes by the points at
Band 7. _ _ 535
“ The manner of ufing this indrument is not more Method of
difficult than the knowdedge either of its conilrudlion oru^nS then’'
effedls. Suppofe, for example, wre are to place it in
the midd of a kitchen garden. By making the ho¬
rizontal condudlor turn round fucceflively, you will be
able to carry the eledlricity over the whole furface of
the propofed ground. The eledlric fluid thus drawn
down, will extend itfelf over all the plants you want
to cultivate ; and this at a time w7hen there is little or
no eledlricity in the lower regions nigh the furface of
the earth.
On the other hand, wffien it happens that the elec¬
tric fluid (hall be in too great abundance in the atmo¬
fphere, in order to take off the effedl of the appa¬
ratus in K, fig. 131. and in «, fig. 132. you have only to
hang to it an iron chain reaching to the ground, or
5sd elfe
E L E C T R
S02
E&clf of die a perpendicalar iron rod, which will have the fame
on Vegeta-f^,^' thr&t °f dcilro>’inS the infulation, and of
tion. • mlenlibly tranfmittmg the ekaric fluid in the fame
u-—v—^ proportion as it is drawn by the points ; fo that there
lhall never be an overcharge of this fluid in the inftru-
ment, and its efka fhall be either fomething or nothin1'-'',
according as you add or remove the fecond chain or the
additional rod.
1 here will be nothing to fear from the fpontaneous
difcharge of this apparatus, becaufe it is terminated
below by proper points in P and q of both machines ;
However, it will be eaiy to furnilh one, by means of
which we may approach the apparatus with perfed
lecurity ; it is only neceffary to hold the hand before it.
This has the form of a great C, and is of a height equal
to the diftance that takes place betwixt the horizontal
condudor and the furface of the earth. This difcharger
near the middle mult be furnilhed with a glafs handle ;
and at that extremity which is direded towards the ccn-
dudor, there mult hang an iron chain made to trail on
the ground. This infoument is an excellent fafeguard.
536
Great ad¬
vantages
to be ex
See %. 133.
liniments.
“ By means of the eledro-vegetometer jull now de-
to oe ex- fc”bed> one maX be able to accumulate at pleafure
peded from ^‘J'S wonderful fluid, however diltufed in the regions
thefe in- above, and condud it to the furface of the earth, in
thole feafons when it is either fcantily fupplied, or its
quantity is infufficient for vegetation ; or although it
may be in fome degree fufficient, yet can never pro¬
duce the effeds of a multiplied and highly increafed
vegetation. So that by thefe means we lhall have an
excellent vegetable manure or nourilhment brought
down as it were from heaven, and that too at an eafy
expence ; for after the conftrudion of this inlirument,
it will coif nothing to maintain it : It will be more¬
over the mold efficacious you can employ, no other
fublfance being fo adive, penetrating, or conducive to
the germination, growth, multiplication, or reproduc¬
tion of vegetables. This heavenly manure is that
which nature employs over the whole habitable earth 5
not excepting even thofe regions which are efteemed
barren, but which, however, are often fecundated by
thofe agents which nature knows fo wHl to employ to
the mold ufeful purpofes. Perhaps there was nothing
wanting to bring to a completion the ufeful difco-
veries that have been made in eledricity, but to ffiow
this fo advantageous an art of employing eledricity
as a manure ; confequently, that all the effeds which
we have already mentioned depend upon eledrici¬
ty alone j and lallly, that all thefe effeds, viz. accele¬
ration in the germination, the growth, and produc¬
tion of leaves, flowers, fruit, and their multiplication, &c.
will be produced, even at a time when fecondary caufes
are againld it: and all this is brought about "by the
eledric fluid, which we have the art of accumulating
over certain portions of the earth, where we want to
raife thofe plants that are mold calculated for our ufe.
By multiplying thefe inttruments, which are provided
at little expence (fince iron rods of the thicknefs of one’s
finger, and even lefs, are fufficient for the purpofe), we
multiply their beneficial effeds, and extend their ufe ad
infinitum.
“ This apparatus having been raifed with care in the
midld of a garden, the happieft effeds were perceived,
viz. different plants, herbs, and fruits,, in greater for-
I C I T Y. part yj
wardnefs than ufual, more multiplied, and of better x-fTcdh of
quality. At tae lame time it was obfervable, that Eiedtricity
during the night, the points P and q, as well ’as the’011 5.egeu“
v_' ' a — y ? ao LUC
upper extremities, were often garniffied with beautiful
luminous Iparks. Thefe fads are analogous to an ob-
fervation which I have often made, viz. that plants
grow bell and are mold vigorous near thunder-rods, C37
where their lituation iavours their developement. They Veg( ration
hkewife ferve to explain why vegetation is fo vigorous m°a vi^°-
m lofty forefts, and where the trees raife their heads
far from the furface of the earth, fo that they feek kA *
as it were, the eledric fluid at a far greater height
than plants lefs elevated 5 while the ffiarp extremities
oi their leaves, boughs, and branches, ferve as fo '
many points granted them by the munificent hand of
nature, to draw down frem the atmofphere that eledric
fluid, which is fo powerful an agent in forwarding vege¬
tation, and in promoting the different fundions ofplants.
“ ft i® not emty by means of the eledricity in the ,538
atmofphere, coiieded by the above apparatus, that augment
one can fupply the eledric fluid, which is fo ne-’k powers
ceffary to vegetation ; but the eledricity named ar-of veSeta-
tjficial anfwers the fame purpofe. However aftonilh-d-n Y T'
mg the idea may be, or however impoffible it may ap-Erkitv.
pear to realize it, yet nothing will be found more eafy
upon trial. Let us fuppole that one wants to augment
the vegetation of trees in a garden, orchard, &c. with¬
out having recourfe to the apparatus deffined to
pump down as it were the eledricity from the atmo¬
fphere, it is fufficient to have a large infulating ftool.
ihis may be made in two ways; either by pourino-
a fufficient quantity of pitch and melted wax up
on the above ffool, whole borders being more raifed
than its middle, will form a kind of frame ; or more
Amply, the ftool (which is likewife called the infula-
tor') fhall only be compofed of a plate longer than
broad, fupported by four glafs pillars, like thofe
ufed for eledrical. machines. One muft take care to
place above the infulator a wooden tray full of wa¬
ter, and to caufe mount upon the ftool a man car¬
rying^ fmall pump in the form of a fyringe. If you
eftablifh a communication between the man and an
eledrical machine put in motion (which is eafily done
by means of a chain that conneds with the condudor
of the machine), then the man thus infulated (as well
as every thing upon the ftool) will be able, by pufhing
forward the fucker, to water the trees, by pourino-
upon them an eledrical fliower; and thus diffbfing over
all the vegetables under its influence a principle of fe¬
cundity that exerts itfelf in an extraordinary manner
upon the whole vegetable economy : and this method
has moreover this advantage, that at all times and in
all places it may be pradifed and applied to all plants
whatever.
Every one knows that the eledricity. is communi¬
cated to the water thus employed ; and it would be eafy.
to obtain the moft ample convidion (if any one doubt¬
ed it), by receiving upon his face or hand this elec¬
trical fliower ; he immediately feels fmall pundures or
ftrokes, which are the effeds of the fparks that iffue
from each drop of water. This is perceived moft fenfi-
bly if there is prefented a metal difli to this eledrical-dew •
for at the very inftant of contad, brilliant flafhes are
produced.
“ That the eledricity received by the man from the
ehain
ELE C TUI C 1 T Y.
Plate CYXXXVin.
EL K O TRl C 1 T Y.
Plate CXC.
ill, E C T K 1C 1 T Y. Plat e C X C I.
A v/y^/Vv* /e*t/.
TIL IE C TLIC IT Y.
Plate CXCIII.
r>//Sr// //,//! J,-,,//,/./■
4 '
6 6.
!•; I, l*', C T JVIC IT Y.
Plate CXCV.
ry!U, ^c5>.
t . //a/.'
MTs. tyO.
*
EI - K C r H ICJ/r V. PI ate r xc vv .
Part VI.
ELECT
Effeifls of chain may be communicated to the tray, we muft put
Ele&ricity a fmaii cake of white iron, upon the end of which he
°n twfaa~may P^ace foot* The tray filled with water is a
w—. - ■ kind of magazine or refervoir to ferve as a continual
fupply to the pump. After watering one tree, you
tranfport the ftool to a fecond, a third, and fo on fuc-
ceftively ; which is done in a Ihort time, and requires
very little trouble*
“ Inftead of the chain, it is better to employ a cord
or twill of pinchbeck or any other metal : by means of
which there can be no lofs of the ele&ric matter, as
there is in the cafe of the chain by the ring points.
Moreover, this metal cord or thread being capable of
being untwifted and lengthened, there will be no occa-
fion for tranfporting fo often the eleftrical machine. It
is almoft needlefs to add, that this firing or metallic
cord, which is always infulated, may reft upon the
fame kind of fupports with thofe which have been ex¬
hibited in OP and s of fig. 131, and 132. This method
is fimple, efficacious, and nowife expenfive, and cannot
be too much employed.
Eafy me- “ If one wants to water either a parterre or com-
thodofap- mon garden, beds and platforms of dowers, or any
plymg elec- plots in which are fown grain or plants of diffe-
this man- rent a£es an^ hmds, no method is mote eafy and ex-
nfer. peditious than the following : Upon a fmall carriage
with two wheels there is placed a framed infulator in form
of a cake of pitch and rofm, as we have mentioned before
in N° 538. The carriage is drawn the whole length
of the garden by a man or horfe fixed to it. In propor¬
tion as you draw the carriage, the metallic cord winds
itfelf upon a bobbin, which turns as ufual. This laft
is infulated, either becaufe the little apparatus that
fuftains the bobbin is planted in a mafs of rofin (when
you choofe the axle to be of iron), or elfe becaufe
this moveable axis is a tube of folid glafs. There
muft alfo be a fupport, which ferves to prevent the
gold thread or the metallic cord from trailing on the
ground, and thus diffipating the electricity j and,
moreover, it ferves as an infulator. To accomplilh
this laft purpofe, it is neceffary that the ring into which
it paffes be of glafs. One may likevvife employ the
infulators and fupports marked OP and r, in fig. 1^1.
and 132. If a gardener, mounted upon an infula¬
tor, holds in one hand a pump full of water, and
with the other takes hold of a metallic cord, in order
to tranfmit the eleftricity which comes from the
conduClor 5 in this cafe, the water being eleCtri-
fi&d, you will have an eleclrical fhower ; which fall¬
ing on the whole furface of the plants which you
want to eleCtrify, will render the vegetation more
vigorous and more abundant. A fecond gardener is
to give additional pumps full of water to him who is
upon the infulator, when he fliall have emptied thofe
he holds } and thus in a little time you will be able to
eleCtrify the whole garden. This method takes hardly
/ longer time than the ordinary one •, and although it
fhould be a little longer, the great advantages refult-
ing from it will abundantly recompenfe the fmall addi¬
tional trouble.
“ By repeating this operation feveral days fucceffive-
ly, either upon feed fown or plants in a Hate of growth,
you will very foon reap the greateft advantages from it.
This operation, equally eafy with the preceding de-
fcribed upon the fubjeCl of watering trees, has beeii put
R I C I T Y.
in praClice with the greateft fuc'cefs. Several other Effedls of
methods, anfwering the fame purpofe, might be de- Electricity
vifed 1 but they arc all of them pretty fimilar to that011 Y^eu‘
juft defcribed. ' . U°^ ,
“ I cannot finiffi this article without mentioning 540
another method relative to the prefent objeft, although elecfkn-'
it be much lefs efficacious than the preceding ones, p’ watcr
It confifts in communicating to water kept in batons, reC^r^;rs
refervoirs, &c. (for the purpofe of watering), the eleo-Scc.
trie fluid, by means of a good eleCtrical machine. To
this end, one muft plafter over with a bituminous
cement all the interior furface of the bafon deftined to
receive the water that ferves for irrigation 5 the na¬
ture of this cement anfwering the purpofe of infula-
tion, will prevent the eleftric fluid that communicates
with the water from being diffipated ; and the water
thus charged with eleClricity will be the more fitted
for vegetation.
“ If the deficiency of the eleClric fluid, or rather a Vegetables
fmall quantity of it, is apt to be hurtful to vegetables, !njure(1 b?
a too great abundance of this matter will Hkewife
fometimes produce pernicious effeCts. The experi¬
ments made by Meffrs Naime, Banks, and other learn¬
ed men of the Royal Society of London, prove fuffi*
ciently this truth. An eleftric battery, very ftrong,
was difeharged upon a branch of balfam ftill holding
by its trunk. Some minutes after, there was obferved
a remarkable alteration in the branch, of which the
lefs woody parts immediately withered, dropped towards
the ground, died next day, and in a Ihort tinle entirely
dried up ; at the fame time that another branch of the
fame plant that had not been put under the eleftric
chain, was not in the fmalleft degree affefted.
“ This experiment repeated upon other plants ffiowed
the fame effefts $ and it was remarked that the attrac¬
tion, occafioned by a ftrong difeharge of the eleftri-
city, produced an alteration different according to the
different nature of the plants. Thofe which are lefs
W'oody, more herbaceous, more aqueous, experience in
proportion, impreffions that are ftronger and much more
Ipeedy in their operation.
‘‘ A branch of each of the following plants, com-
pofing an electrical chain, it was obferved by thefe
able philofophers, that the balfam was affefted by
the difeharge of the battery in a few moments af¬
ter, and periihed next day, The leaves of a marvel
of Peru did not drop till the day following that 5 and
the fame phenomenon happened to a geranium. Se¬
veral days elapied before there was obferved any fa¬
tal ell eft on the cardinal flower. The branch of a
laurel did ndt ffiow any fymptoms till after the lapfe
of about 13 days, after which it died •, but it was a
full month before they perceived any fenfible change
on the myrtle j at the fame time they conftantly obferved
that the bodies of thofe plants and branches which had
formed no part of the chain, continued to be freffi, vi¬
gorous, and covered with leaves in good condition *. * Phil.
“ It hardly fever happens that the fuperabundance of Tranf-
the eleftric fluid exifting in a fmall portion of the at-Vul'‘X1V’
mofphere where a plant is fituated, can be fo great as
that which took place by the explofion of the ftrong
battery of Mr Naime, direfted particularly upon one
branch j or if this Ihould happen, it can only be upon
a few individual plants in a very fmall number.
3 I 2
INDEX.
-804
ELECTRICITY.
Index.
INDEX.
ACHARD's experiments on ice, N° 5
divifion of the fcale of
an electrometer, 68
ABion, eleCtric, law of, 366—368
fhewn by experiment, 368
JRpinus's experiments on the tourma¬
lin, 21
on fulphur, 27
theory of eledricity, 294—^,47
defeCt in, fupphed, 3 20
defended, 3 21
Air, effeCt of, in electricity, 63
decompofed by eleftricity, 165
rarefied by an explofion, 168
when hot, a conductor, 227
how excited, 229
by friCtion, 23 O
evaporation, 231
of a room, to eleCtrify, 234
plate of, to charge, 235
eflential to eleCtrical phenomena, 237
Amalgam, eleCtrical, 13
preparation of, ib.
Amber, eleCtricity of, known to
Thales, page 645, note (a.)
gives name to eleCtricity, 1
Ammonia decompofed by eleCtricity, 166
Apparatus, eleCtrical, Part II.
Atmojphcre, eleCtric, vifible, 191
eleCtricity of, conftant, 495
always pofitive in
dry weather, ib.
ftrongelt in foggy
weather, 503
table of obferva-
tions on the, p.792.
periodical flux and reflux
obferved in the, 504
caufes affeCting the elec¬
tricity of the, 511—520
Atmofpheres, eleCtric, hypothefis of,
refuted, 408
AttraBion and repulfion, eleCtrical,
illuftrated, Part III. Ch. i.
through glafs explained, 292
Aurora auftralis, 522
borealis, phenomena of, 521
attributed to polar
fires, 523
evidence for the e-
leCtrical origin of, 524
theory of 5 25
borealis, experiment of, 190
Axioms on atmofpherical eleCtricity, 510
B
Baldwin, curious phenomenon obfer¬
ved by, 497
Battery, eleCtrical, 101
how conftruCted, 3 ic
Battery, eleCtrical, compendious, N° no
rules for, 112
origin of, 113
Van Marum’s, 114
charge of, how efti-
mated, 204
Beccaria's fubftitute for glafs, 105
vindicating eleCtricity, 422
obfervations on atmofphe¬
rical eleCtricity, 486
idea of the production of
hail, 488
Bells, eleCtrified, 61, 80, 126
Bennet's eleCtrometer, 69
advantages of, 71
defeCts of, 74
how remedied, 75, 216
applied to kites, 496
doubler, 247
mode of remedying the de¬
fects of the doubler, 25 2
Bertholet' remarks on the fufion of
metals by eleCtricity, 3 28
Bertholon's obfervations on eleCtrify-
ing vegetables, 531
eleCtro-vegetometer, 53 2
Bo/e introduces the prime conductor,
page 660, note (1).
Brooke's method of making batteries, 11 x
of coating jars, 108
of repairing jars, 115
experiments on the Leyden
phial, 140
on the force of bat¬
teries, 20 2
mode of conftruCting gages, 239
Brugnatelli fuppofes the eleCtric fluid
to be an acid, 365
and chain, eleCtrified, 413
Canals, communication of eleCtricity
by, explained, _ _ 374“392
uniformity of fluid in very
flender, 374
Canton firft employs an amalgam, 13
Canton's experiments on glafs, 16
eleCtrometer, 66
Capillary fyphon, 77
Carbonic acid decompofed by eleCtri¬
city, page 694, note (1).
Carmoy's experiments on eleCtrifying
vegetables, 53 O
Cavallo's experiments on glafs tubes, 16
on exciting powders, 31
improvement of Bennet’s e~
leClrometer, 75
pocket eleCtrometer, 76
directions for fuiing metals, 171
experiments on colours, 193
Cavallo's experiments on the eleCtro-
phorus, N° 208
on the non-conduCting
power of a vacuum, 240
improvement of the conden-
fer, . 246
collector of eleCtricity, 2q4
multiplier of eleCtricity, 255
ufe of in obfervations
on atmofpherical
[eleCtricity, 300
conftruCtion of kites, 49 2
means of avoiding danger
from the kite, 493
conclufions from his experi ¬
ments with the kite 493
atmofpherical eleCtrometer, 498
eleCtrometer for rain, ' 499
Cavendijh's experiments on air, 163
theory of eleCtricity, 348
of the aCtion of points, 414
of charged glafs, 416
method of meafuring the
charge of a jar, 420
Cement for eleCtrical apparatus, 37
for broken jars, 113
Chocolate, eleCtricity of, 28
Cigna's experiments on filk, 18
with charged plates, 131
Coating for cylinders and globes, 40
for jars and plates, 107
ColleBor of eleCtricity, 234
Colours, experiments on, 193
Compenfated eleCtricity, 411
Condenfer of eleCtricity, 243
improvement of, 246
ConduBors, table of, 3
■ diltinguilhed from elec¬
trics by Gray, page 646,
note (b).
all imperfeCt, 4
prime, of a machine, 39
introduced by Bofe, page
660, note (1).
capacity of, 243
conjugate, 244
againft lightning, invented
by Dr Franklin, 464
ftiould be of the belt con¬
ducting materials, 467
of fufficient diameters, 468
perfectly continuous, 469
interrupted, effeCt of, 473
Ihould be as ftrait as pofli-
Me, 473
pointed, 476
Configurations, curious, produced by
eleCtricity. 273
Copper forms the belt conductors
againft lightning, 467
Cotte's
Index.
E L
Cone's axioms on atmofpherxcal elec¬
tricity, N° Sio
Cotton, eleftrified, # 4
Coulomb afcertains the law of ele&ric
aftion, 3^7
finds that conduftors are e-
lectrical only at the fur-
face, 359
Coulomb''s experimerwts on the denfity
of the ele&ric fluid, 397
Cuneus''s experiment, _ 9^
Cuthbertfon's proofs of the oxidation
of metals by eleftrici-
ty, page 701, note (z).
electrometer, 203
experiments on the effe&
of breathing into jars, 205
mode of eftimating the
power of machines, 224
method of diftinguilhing
the two elechicities, 266
Cylinder, advantages of, 39
directions for choofing, ib.
date of the infide of, during
excitation, 212
D
Dalibard's experiment proving the
identity of lightning
and eleCtricity, 442
Dancing balls, 61
Danger from lightning, means of
avoiding 4^P»
from atmofpherical eleCtrici¬
ty, inftances of, 494, 496, 497
approaching, figns of, 480
Darwin's moveable.doubler, 249
Di/charger, Henly’s univerfal, 117
Difcharging rod, conftruCtion of, 116
Morgan’s, 119
Doubler of eleCtricity, 247
manipulation of, 248
moveable by Darwin, 249
revolving by Nicholfon, 250
defeCts of, 251
how remedied, 252, 253
Du Faye's theory of eleCtricity, 28Q
E C T R I C I T
Elebiric power, attraCts and repels, N° 60
makes liquids flow
through capillary
fyphons, 77
communication of, to
eleCtrics, 93
paffageofjlhewn, 136—139
mechanical effeCts of,
Part III. Ch. viii.
velocity of, 270
See Eleflric Fluid.
EleBrical apparatus defcribed, Part
II.
machine, general conftruc-
tion of, Part II. Ch. i.
different parts of, 34
various, 46—51
directions for ufing,
Part II. Ch. iii.
power of, how efti-
mated, 221
with filk, 226
horfe-race, 84
orrery, 85
jack, 155
air thermometer, 168
Eleciricity, general idea of, 1
origin of the name, I
properly the fcience, 2
applied to the caufe of
phenomena, ib.
produced in various ways, 10
by friCtion, 11
heating and cooling, 21, 24
melting, 25—28
breaking, 29
evaporation, 32
of wood {havings, 30 i
powders, 31
fmall degrees of, how af-
certained, 258—261
theories of, Part IV. Ch; i.,
difcovered to come from
the earth, 282
direction of, doubts con¬
cerning, 284
phenomena of, depend on.
redundancy of fluid or
E
Eggs, illuminated,
JLleclric fluid, nature of, 281,355
materiality of, proved, 356
differs from caloric, 358
from light, 360
probably a compound, 361
generally confined to
the furface of con¬
ductors, _ 359
fuppofed to be an acid, 365
law of aCtion ofj 3^ •
difpofition of, in two
parallel plates, 371
in a fphere, 3 7 2
Eleiiric power, caufe of dearie phe-
* nomena fo called, 2
matter, 3°5 '
induced, 344
compenfated, 411
vindicating, 422
pofitive and negative, 7
how diftin-
guifhed, 128
obfervations
on 130
attraa each
other, . 3 25
produced in
the fame
conduaor, 215
vitreous and refinous, 8
EteElrics, what, 1 -
table of, w 5
Y. 805
EleBrics, all imperfea, N° 4
ufed as infulators, 6
coated, effeas of, 93
refinous, when melted be¬
come conduaors, 268
nature of, 296
only fo fuperficially, 410
EleBrometer, Nollet’s, 65
Canton’s, 66
{land of, ib*
quadrant, 67
fcale of, how belt divid¬
ed, 68
Bennet’s, 69
fenfibility of, 71
rendered more fen-
fible by a candle, 73
defeas of, 74
improvement of, 75
Cavallo’s pocket, 76
Lane’s, 199
by Adams fimilar to
Brook’s, 201
Cuthbertfon’s, 203
Robifon’s comparable, 206
mode of ufing, 367
Cavallo’s atmofpheri¬
cal, 498
for the rain, 499
EleBrophorus defcribed, 207
phenomena of, ib.
experiments on, by Ca-
vallo, 208
by Morgan, 209
theory of, 423
. primitive flate of, 425
common Hate of, 426
neutral ftate of, 429
charged ftate of, 430
charging ftate of, 431
aaivity of, how renew-
ed, 434
EleBrofcopes. See EleBrometers. .
EleBro-vegetometer, defcribed, 532
Evaporation produces elearicity, . 32, 231
increafed by elearicity, 233
experiments on, by Sauf-
fure, . 509
a:caufe of atmofpherical
ekaricity, 512
Excitation, 4
modes of producing, 10—31
of powders, 31
remarks on, by Mr Ni¬
cholfon, 210—220
mode of increafing, 219
how performed without
the'filk flap, N° 217
velocity neceffary to pro¬
duce the greateft de¬
gree of, 214
Experiments on glafs by Hawkefbee, 13
by Cavallo, 14
on filk by Symmer, 17
by Cigna, 18
Experiments
8o6
E
Experiments on paper, N° 19
on the tourmalin, 24
on fulphur by Wilcke, 25
by /Epinus, 26
on porvders by Cavallo, 31
on attraftion^and repul-
Con, Part III. Ch. 1.
on points, 80—84
on the Leyden phial, 96, 122,
etfcq.
on the eleftric fpark, 130
on inflammation, 138
on the gafes, 164—166
on decompofing water, 169
on fufing metals, 171—.173
on eleclric light, —190
on colours^ 193
on the eleftrophorus, 208, 209
on evaporation, 231—233
on the non-condudling
power of a vacuum, 238
. —24°
on the capacity of con¬
ductors, 243
on the velocity of the
eleCtric fluid, 271
proving the identity of
lightning and eledtri-
city, . 441, 442
on atmofpherical eleCtri-
city, Part V. Ch. II.
on evaporation by Sauf-
fure, 509
Experiments, entertaining.
Dancing figures, 61
Capillary fyphon, 77
Eledtrical well, 79
horfe-racc, 81
orrery, 8 2
EleCtrified cotton, 84
Drawing fparks. 86
Dancing balls 94
Leyden phial, 96
EleCtrified fpider, 1
Lateral explofion, 127
Leyden vacuum, 138
Double jar, 139
Magic picture, 154
EleCtrical jack, 15 5
Self-moving wheel, 156
To fire rofin, 158
fpirits, 139
hydrogen gas, 160
gun-powder, 162
Inflammable air lamp, l6i
EleCtrical air thermometer, 168
To fufe wires, 171
To burn wire by eleCtricity, 173
To illuminate water, 173
eggs, 176
Canton’s phofphorus, 178
Spiral tube, 180
Luminous word, 181
conductor, 188
Conducting glafs tube, 189
L E C T R i c I T
Aurora borealis, Is™ jgo
Vilible eleCtric atmofphere, 191
To perforate a card, &c. 196
To eleCtrify the air of a room, 234
To charge a plate of air, 233
I o imitate the planetary motions, 264
To fpin fealing-wax into threads, 272
lo form curious configurations, 273
EleCtrified can and chain, ‘313
Thunder-houfe, 470
Po wder-houfe, 471
F
Flame, a conductor, 26^
Fogs have a fmell like an excited glafs
tube, 489
Franklin difeovers the feat of the
charge in the Leyden
phia!, 124
Franklin's experiments on metals, 171
theory of eleCtricity, 287—292
difficulty to explain the at¬
traction between nega¬
tive bodies, 288
theory of the Leyden phial, 291
conjecture on the identity
of lightning and eleCtri-
cit7, _ 438
comparative view of their
effeCts, 439
propofal for proving their
identity, 440
experiment proving their
identity, 44!
invention of conductors a-
. gainfl: lightning, 464
directions for their con-
ftruCtion, 46 3
FriBion excites eleCtrics, u
obfervations on its mode of
aCtion, 364
G
Gafes, decompofed by eleCtricity, 133
Gilbert, Dr, difeovers glafs to be an
eleCtric. 12
Glafs, when firlt ffiovvn to be an elec¬
tee, ib.
excited, phenomena of, Part I.
Chap. i.
durability of its eleCtricity, 16
belt eleCtric for machines, 33
fubftitute for, 103, 225
red hot, a conductor, 268
powdered, a conductor, 269
impermeable to the eleCtric
fluid, 409
Gralatb firft employs a battery, 113
Grey diftinguiffies eleCtrics from con¬
ductors, p. 646. note (b).
difeovers filk'to be an eleCtric, 16
fuppofes a perpetual eleCtricity
in fulphur, 27
Y. Index.
Hail, Beccaria’s idea of the forma-
rr ,0 ti0n 0f’ N° 488
IIaldane'ls, Colonel, mode of eftima-
ting the charge of a
r* battery, 2Q4
tlawkejbee's experiments on glafs, 13-
renders fealing-wax tran-
fparent,
Henhfs experiments on chocolate, 28
quadrant eleCtrometer, 67
univerfal difeharger, jjy
obfervations on chargedplates, 132
atmofpherical
eleCtricity, 49 a
Honfes, belt means of protecting from
lightning,^ 477.
Ice, when free from air, a non-con-
duCtor, ^
Induced eleCtricity, 344
illuftrated, 399
may become per¬
manent, 347
Ingenhoufds eleCtrical machine, 417
fubititutes for glafs in
machines, 223
denies the effeCt of elec¬
tricity on vegetation, 329
Infulation, what, 6
K
Kienmayer's amalgam, p. 639, note (k).
Kinnerjletfs eleCtrical thermometer, 168
obfervations on atmofpe-
rical eleCtricity, 484
Kite, Franklin’s experiment with, 441
Cavallo’s conftruCtion of, 492
directions for making experi¬
ments with, 493
Bennet’s eleCtrometer applied
M, 496
Kief’s, Van, difeovery of the elec¬
tric ffiock, 97
Klin cock's method of eftimating fmall /
degrees of eleCtricity, 242
H
Hail, fuppofed to be produced by e-
leCtricity, 487
Latnp, inflammable air, 161
Lane's eleCtrometer, 199
Lateral explofion, \ 27
Leyden phial, conftruCtion of, 93
charging and difcharging, 96
difeovery of, 97
progreffive improvement, 100
beft form of, 103
infulated, cannot be
charged, 122
charge of, where feated, 123
gradually difeharged, 1 23
lateral explofion of, 127
Brooke’s experiments
on» 14a
Milner’s experiments.
on, 141
felf-charging, 137
ftates of its furfaces, 134—140
Leyden
Index. E
Leyden phial, charged without fric¬
tion, N° 148
when damped within,
receives a higher
charge, 205
Franklin’s theory of, 291
phenomena of illuftrated, 415
theory of, 4x6
charge of, how afcer-
tained, 4 20
Lichtenberg's method of eftimating
fmall degrees of e-
leftricity, 242
curious experiment with
the eleftrophorus, 274
Light differs from eleftricity,
eleftric, varieties of, 91
firft feen by Otto Gue¬
ricke, p. 672, note (c).
flar and pencil of, 129
appearance of, on paper, 133
experiments on, by Pvlr
Morgan, 1 8 2—187
may become vifible in
all bodies, 182
more vifible in imper-
fe£t conductors, 183
more vifible in rare
jthan in denfe media, 184
more brilliant in fmall
bodies, 185
like folar light in re-
frangibility, 186
affeCled like folar light
by various media, 187
invifible in a perfect
vacuum, 237
Lightning and eleflricity, fimilar ef-
fe£ts of, 439
identity of, proved
by Dr Franklin, 441
flafh of, form of, 446
colours, of, 447
effeCts of, on a building, 453
fufion of metals by, not a
cold fufion, 454
fets fire to inflammable bo¬
dies, . _ 455
tears refilling bodies, 456
kills animals, 457
Luminous wmrd, 181
conduCtor, 188-
Lyncurium, the tourmalin fo called by
Theophraltus, N° 20
Lyons'’s experiments to prove the per¬
meability of glafs,. 409
M
Machine. See EleBrical.
Magic picture, 1-54
Magnetifm given to needles by elec¬
tricity, 276
Maimbray firlt eleCtrified plants, 526
il/tfr//OT,j’,.Van, eleCtrical machines, 48, 49
batteries, 114
L E C T R I C
Marumi's, Van, experiments with the
gaffes, N° 166
experiments with me¬
tals, 172
experiments on mag¬
netic needles, 278
AIa%eas'ls, abbe, experiments on at-
mofpherical eleCtricity, 483
Mercurial phofphorus, 14
Metals fufed and oxidated by eleCtri-
city, _ 171
fufibility of, comparative, by
heat and by eleCtricity,
N° 172. and p. 700. note
(Y)-
oxides of, reduced, 174
fufion of, by lightning not a
cold fufion, 454
Milner''s obfervations on the Leyden
phial, 120
Mourner's experiments on atmofphe-
rical eleCtricity, 482
Morgati's rules for conitruCting bat¬
teries, 112
for difeharging rods, 118
difeharging rod, 119
experiments on eleCtric
light, 182—187
experiments on the infula-
ted eleCtrophorus, 209
experiments on the non-
conduCfing powTer of a
vacuum, 23 8
obferv/tions on the effeCt
of FriClion, 364
obfervations on the diftance
at which thunder may
ftrike, 46°
propofal for preventing dan¬
ger to buildings from
lightning, 477
Multiplier of eleCtricity, 255
Multiplying wheel, its ufes, 41
N
Nairne's eleCtrical machine, 50
method of fecuring jars, 121
Neutral points, feveral in an imper-
feCt conduCtor, 346
Neutrality of bodies that are redun¬
dant or deficient, 313
Nicholfon's obiervations on the elec¬
tric fpark, 130
inftrument for diftinguifh-
ing the two electrici¬
ties, 132
remarks on excitation, 210
—220
revolving doubler, 250
fpinning condenfer, 257
improvement of Bennet’s
eleCtrometer, 262
remarks on the glafs cafe
of ditto. 263
Nitric acid formed by eleCtricity, 165
Nitrous gas decompofed by eleCtri¬
city, 166
T Y. 807
Nollet's, abbe, eleCtrometer, N° 65
theory of eleCtricity, 285"
conjectures on the identity
of lightning and eleCtri¬
city, _ _ 437
experiments on elcCtrifying
plants, 527
Non-conduclors. Vid. Elctirics.
O
Opaque bodies made tranfparent, 13, 179
Otto Guericke, firit confiruCts an elec¬
trical machine, p. 656,, note (f).
P
Paper, eleCtricity of, 19
a good rubber, 43
ufe of as a coating, 108
Pearfon's directions for decompofing
water by eleCtricity, 170
Peart's idea of eleCtric atmofpheres, 407
Pho/phorus, Canton’s, illuminated, 178
Planetary motions imitated, 82, 264
Phz/c-machine fuperior to one with
a cylinder, 223
Plates of glafs, their inconveniences, 3 8
Points, aCtion of, 80—84
explained, 414
Polarity of magnetic needles reverfed
by an eleCtric ftiock, 276
Powder-lwufe, experiment, 471
Priejlleifs eleCtrical machine, 46
experiments on tourmalins, 24.
gafes, 165
R
Rain fuppofed to be owing to eleCtri¬
city, . 487
Read denies hot air to be a conductor, 228
Read's obfervations on atmofpherical
eleCtricity, 501
Reid's portable eleCtrical machine 51
Repuljion between negative bodies un¬
accounted for by Frank¬
lin, 288
attempts to account for, 389
explained, 40!'
Returning ftroke, theory of, 462
effects of, over-rated, 463
Ribbons, experiments on, by Cigna, 18
Rickman's experiment with coated
plates, 153
death by lightning, 458
Robifon's eleCtrometer, 206
improvement of Bennet’s
doubler, 253
afeertains the law of eleCtric
aClion experimentally, 367
Ronayne's obfervations on atmofpheri¬
cal eleCtricity, 489;
Rouland's filk eleCtrical machine, 226
Rubber, firit employed by Winckler
p. 657, note (g).
cohitruCtiom of, 4 2
improvement of, 43
filk flap of, the principal caufe
of excitation, 211
RuJJel's hypothefis, 362
S
658 E L E C T H I
q Spotitaneeus eleSricity,
Stanhope's, Lord, theory of the re¬
turning fttoke, 462
Steam, a condu&or, 267
Suiphtir, excited, phenomena of, Part I.
Ghap. v<
experiments on, by Wilcke, 26
by TEpinus, 27
durability of its ele&ricity, 28
Swinden's, Van, experiments to fhow
that powdered glafs is a
a conduftor, 269
Symmer's experiments on filk, 17
on charged
plates,
on the petfor
ation of pa
per,
7U T
Silt, eleftric power of, 16 Talc, a good dearie for charging, 106 Volta's ‘“™P<
excited, phenomena of, Part I, Theory of the early ekancianj, 279 elettrophoms,
-- of Du Faye, *
of Dr Watfon,
of Abb6 Nollet,
of MrWilfon,
of Franklin,
of iEpinus,
of Mr Cavendiih,
of two fluids,
Salts, when dry, non-condu&ors, N° 5
Saturation defined, 301
Sau(j'urc',s, Theodore, experiment with
carbonic acid, p. 694.
note (i)4
SauJJure's, Horace, obfervations on
atmofpherioal eledtri-
city, 502—508
experiments on evapora¬
tion, _ 569
Sealing-wax, excited by breaking, 29
fpun into threads,
Shavings, wood, eleftricity of,
Ships, how belt protected from light
nlnS» a
Shock, eleftric, difeovered,
perforates cards,
272
30
47 8
98
196
gives polarity to needles, 276
17
18
Chap. ii.
experiments on by Symmer,
Cigna,
firfi: employed as a rubber by
Nooth, p. 657, note (h).
Smoke, a conduftor, 267
Snow, fuppofed to be owing to elec¬
tricity, 487
Spark, eleftric, figure of,
length of,
found of,
force of,
light of,
peculiar odour of,
pofitive and negative
diitinguilhed,
chemical effefts of,
Part III. Chap. vii.
Spider, eleftrified,
Spiral tube,
87
88
89
90
91
92
experiments mi
CITY. Me*.
N° 25 Thunder, diftant, danger from, . N° 461
explained, 462
rods, mode of cbnftrufting, 444
houfe, experiment of the, 470
Tourmalin^ eleflricity of, Part I. Chap. iv.
experiments oh by TEpinus, 21
by Prieftley, 24
Tr emery's defence of the theory of two
fluids, 351
Troojlwyk's, Van, experiments on the
decompolition of Water, 169
u
Vacuum, non-condufting power of, 237
—240
Vapours, condenfation of a caufe of
atmofpherical eleftricity, 512
Vegetables, effeft of eleftricity on, Part VI.
method of eleftfifying, 532
Vindicating eleftricity, 422
161
 —, 207
experiments that led to the in¬
vention of the condenfer,
condenfer,
w
Water decompofed by eleftricity,
illuminated,
Watfon's experiments on the velocity
of eleftricity,
theory of eleftricity,
*51
196
280
283
285
286
287
294—347
348
349
243
245
169
'IS
litating againft, 352 Well, eleftrical,
114
126
180
of Profeffor Ruffel, 3^2
of Mr Wilkinfon, 363
Thunder, always preceded by light¬
ning, 448
found of, 449
diftance of, how meafured, 450
explofion of, explained, 451
generally confined to the
heavens, 452
ftorm, progrefs of, 445
explained,
Wheel, felf-moving,
Wilcke's experiments on fulphur,
miltake,
Wilkinfon's hypothefis,
Wilfon's, W. compound condenfer,
Dr, theory of eleftricity,
Winckler introduces the rubber p.658.
note (g).
Wolff's improvement of the rubber,
271
283
79
412
156
25
418
363
256
286
43
N. B. In conjul,inS .he plate, on eleOricity, the reader is reyuejied to follow the numbers of the figure,, and not thofe of the plate,
after the frjl.
END OF THE SEVENTH VOLUME.
DIRECTIONS »or placing the PLATES of Vol. VIl.
Part L
Platfe CLXVIII. to face
CLXIX.
CLXX.
CLXXL—CLXXIV.
CLXXV.
Page 162
i8o
172
214
250
PlateCLXXVI. to face
CLXXVII—CLXXXIII.
Part II.
CLXXXIV.—CLXXXVI.
CLXXXVIL—CXCIX.
Page i8»
324
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80a
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