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A GUIDE
TO THE
SCIENTIFIC KNOWLEDGE
OF THINGS FAMILIAR;
BY
REV. DR. BREWER,
TRINITY HALL, CAMBRIDGE,
Beud Master of King's College School, Norwich-in union with Kmg'j
College, London.
EarefulIj 3eb[fset, ault abaptr for use Itn ljaml[es
al~.%ctools of the  [nfte'  States.
NEW YORK:
JAMES MILLER, 522 BROADWAY,
(SUCCESorP TO C. S. FRANCIS & CO.)
1864.




Entered, according to Act of Congress, in tbe year 1860,
By C. S. FRANCIS & Co.,
in the Office ct thte Clerk of the I)istrict Court of the Soutnsrm
District of New Ycrk




PREFACE.
No science is more generally interesting than
that which explains the common phenomena of
life. We see that salt and snow are both white,
a rose red, leaves green, and the violet a deep
purple; but how few persons ever ask the reason
why!  We know that a flute produces a musical
sound, and a cracked bell a discordant one-that
fire is hot, ice cold, and a candle luminous-that
water boils when subjected to heat, and freezes
from cold; but when a child looks up into our face
and asks us " why "-how many times is it silenced
with a frown, or called "very foolish for asking
such silly questions!"  The object of the present
book is to explain about 2000 of these questions
(which are often more easily asked than answered)
in language so simple that a child may understand
it, yet not so childish as to offend the scientific.
In order to secure the strictest accuracy in the
answers, the most approved modern authors have
been consulted, and each edition has been submitted
to the revision of gentlemen of acknowledged reputation for scientific attainments. Sincere thanks
ire due to the REv. A. BATII POWER, MI. A.,
md to ROnERT JAMES MIANN, ESQ., M. R. 0. S., of
Buxton, for their most careful revisions of the
whole book, for many excellent hints and useful
Additions. In conclusion, the almost unparalleled
uccess of this little volume, of which 25,000 copies




Vi                  PREFACE.
have been printed, since the year 1848, is an in.
controvertible proof of its acceptability; and has
induced the author to spare neither labor nor expense to render his " Guide to the Scientific Knowledge of Things Familiar" instructive and amusing
to the young, as well as to those of maturer life.
To teachers of schools it may be advisable to
state, that, as every question has been again and
againi ubmitted to a most rigid investigation, no
material alterations will be made in future editions.
A remarkable instance came before the author a few
months since of the statement made in the early part of
this preface. The conversation was about smoke —why it
was black, and not white like the fine (lust of lime. A
little child who was present, asked, "Why is the kettle so
black with smoke?" Her papa answered, " Because it
has been on the fire;" " But" (urged the child) " what is
the good of its being black?"  The gentleman replied,
" Silly child-you ask very foolish qllestions-sit dewn
and hold your tonCgue." lie might have read pp. 186,
and 186, and answered the child more discreetly.
TunE An1.EnIcAN PUBnlsIEns offer their revised edition
of this useful book, in full confidence that it will meet
with an equal and universal acceptance both in families
and schools, throughout this country. They believe it
will bo fund to contain an amount of useful information
never before collected in a shape so convenient for study,
and so easy for refrenee.




SUBJECTS OF THE CHAPTERS.
PART I.-HEAT.
BIAGI
Introduction....                                 9
I.-The SUN a source of heat..                    10
II.-ELECTRICITY a source of heat...   11
II.-Thunder and lightning    11-36
III.-CHEMICAL ACTION a source of heat              36
III.-Chemical action..  36
IV.-Combustion...  39
V.-Smoke and smoky chimneys   62
VI.-Lamps and candles..  74
VIL.-Animal heat..    83
VIII. —IMECHANICAL ACTION a source of heat   94
VIII.-Percussion...  94
IX.-Friction....  97
X.-Condensation, or Compression  100
XI.-EFFECTS OF HEAT.                             102
XI.-Expansion... 102
XII.-Same subject continued. 117
XlII.-Liquefaction..     121
Vaporization (clouds). 121
XIV.-Evaporation.. 147
XV.-CO2II.UNICATION OF HEAT...  155
X'\.-Conduction... 155
XVI. —Absorption... 173
XVII. —Rflection... 179
XVIII.-Radiation (dew). 182
XIX.-Convection (boiling). 213




PART II.-AIR.
XX.-THE ATMOSPHERE..                        2 19
Gases The Blood. Rust. Tarnish, &c.
XXI.-CARBONIC ACID GAS...             238
Froth. Effervescence. Fermentation, &c.
XXII.-CARBURETTED HYDROGEN GAS.                261
Fire-damp. Safety lamp, &c.
XXIII.- PHOSPHURETTED  IHYDROGEN GAS.  265
Ignis Fatuus. Ghosts, &c.
XXIV.-WIND.                268
XXV.-BAROMETER... 296
Ten Special Rules, &o.
XXVI. -SNOW.  HAIL.  RAIN                      309
XXVI.-AVATER.... 319
XXVIII.-IE...                                325
Freezing mixtures. Frost. Swimming, &c.
XXIX.-LTGHT.                338
Reflection. Telescopes. Refraction.
Spectacles. Rainbows. Color.
XXX.-SOUND.377
Ear trumpets. Echoes, &c.
PART 111.-MISCELLANEOUS.
Attraction. Anti-putrescents. Dreams. Color.
Ink. Iron. Bread. Horn. India-iubber.
Starch. Meat. Butter. Mirrors. Bricks.
Milk. Steel. Manure. Soap, etc....   387
Antidotes to Poisons........  452
Glossary...........     454
Index.............   455
Index to Part III. —Miscllancous Questions.                                   485




PART I.
HEAT.
INTRODUCTION.
Q.  Wlhat is HEAT?
A, The sensation of warmth.
Q.  hlow is this sensation produced?
A.  When we touch a substance hlot.
ter than  ourselves, a subtile invisible
streamn flows from  the hotter substance,
and produces on our nerves the " sensation of warmth."
Q.  tIltat is that'"subtile invisible stream"
CALLED, which flows from the hotter substance?
A. CALO RIn. Caloric, therefore, is
the cagent, which produces the sensation
of iwarmth; but HEAT is the sensation
itself.
Q.  What are the four principal SOURCES of
heat?
A.  1.- The Sun.  2. — Electricity.
3.-Chemical Action; and 4. —Mechanical Action.
(1)       9




10                HEAT.
Q.  TThat are the principal EFFECTS of heat?
A.  Expansion, Liquefaction, Vapor.
ization, and Ignition.
CHAPTER I.
THE SUN.
Q.   W'hat is the PrINCIPAL source of heat?
A.  The SuN.
Q.  ITVhy do BUrNING GLASSES set fire to sub.
stances submitted to their power?
A. Because, when the rays of the
Sun pass through the burning glass, they
are bent toward one point, called the
"focus;" in consequence of wlhiclh, the
light and  heat at this poilt are very
greatly increased.
Q.  Wh/y is there a DARK RuIM round this
focus?
A.  Because  the  rays of light are
bent front the rim  into the focus; and,
as the rim is deprived of these rays, it is
darkened.
Q.  Are ALL the rays bent into one point?
A. Not quite all: and, therefore, the
rim  round the focus is not quite black,
but only dini.




ELECTRICITY.               1I
CHAPTER II.
ELECTRICITY.
Q.   Thtat is the SECOND chief source of heat?
A,  ELECTRICITY.
Q.   What is LIGHTNING?
A.  Lilghtning  is  accumulated  elec.
Iricity discharged from the clouds.
Like that from a " Leyden jar."
Q.   What CAUSES the discharge of an electric
cloud?
A.  When a cloud, overcharged with
electric fluid, approaches another which
is undercharged, the fluid rushes from
the former into the latter, till both contain the same quantity.
N. B. It is generally supposed that there are two different sorts of Electricity-one Vitreous, and the other
Resinous.
Q.  Is there any OTHER cause of lightning, besides the one just mentioned?
A. Yes; sometimes mountains, trees,
and steeples, will discharge the lightning fromn  a cloud floating near; and
sometimes electric fluid rushes out of the
earth into the clouds.
Q. What produces ELECTRICITY in the CLOUDS?
A.  1st-The  evaporation  from   the
earth's surface;




12           ELECTRICITY.
2dly-The chemical changes, which
take place on the earth's surface; and
3dly-Currents  of air of unequal
temperature, which excite electricity by
friction, as they pass by each other.
Q.  How I1IGII are the LIGIITNING CLOUDS
from the earth?
A. Sometimes they are elevated 4
or 5 miles high; and sometimes actually
touch the earth with one of their edges:
but they are rarely discharged in a thunder storm, when they are more than
700 yards above the surface of the
earth.
Q.  How high are the clouds GENERALLY?
A.  In a fine day, the clouds are
often 4 or 5 miles above our heads; but
the average height of the clouds is from
11 to 2 miles.
Q.  Why is lightningm sometimes FOrlCED?
A. Because the li(lghtningf-cloud is a
long Tway off; and the resistance of the
air is so great, that the electrical current is diverted into a zig'-zag, course.
Q.  How does the resistance of the air make the
lightning zig-zag?
A.  As the lightning condewnscs the
air in the immediate advance of its path,
it flies from side to side, in order to pass
where there is the least resistance.




,LIGHTNINO.               13
Q.  Why, are there sometimes TWO flastes of
forked lightlaing at the same moment?
A.  Becaulse (in very severe storms)
the flash will divide into ttwo or more
parts; each of which will assume the
0 * 
zig-Zag form.
Q. ITrhy is the FLASHI sometimes quite STRAIGHT?
A.  Because  the  lightning-cloud  is
near the cuart.'; and, as the flash meets
with  xv >::,  little  resistance, it is  not
diverted; (in other words) the flash is
straigll:
Q.  I[/wt is SHEET LIGHTNING?
A.  Eitler  the reflection  of distant
flashes not distinctly visible; or else
several flashes intermingled.
Q.  VIhat OTHER form does lightning occasion.
ally assume?
A.  Sometimes the flash is globular;
which is the most dangerous form  of
lightning-.
Q.  TIhcat are those BALLS of FIRE, which
sometimes fall to the earth in a thunder-storm?
A.  Masses of explosive gas, formed
in the air: they generally move more
slowly than lightning.
Q.  Why are BALLS of FIRE so very DANGERA.  Because, when  they fall, they




14           ELECTRICITY.
explode like a cannon; anti occasion
much mischief.
Q.  Do these BALLS of FIrE ever run along thi
ground?
A. Yes; sometimes they run a considerable way along the ground, and
explode in a mass:
At other times they split into numerous smnaller balls, each of which explodes
in a similar manner.
Q.  Ifhat MISCIIEF will these balls of file
produce?
A. They will set houses and barns
on fire; and kill all cattle and human
beings,  which happen to be in their
course.
Q.  VWhy does LIGHTNING sometimes KILL men
and beasts?
A. Because (when the electric current passes through a man or beast) it
produces so violent an action upon the
nerves, that it destroys life.
Q.  WIHEN is a person struck DEAD by light.
ning?
A.  Only when his body forms a part
of the lightning's path; i. e. when the
electric fluid (in its way to the earth)
actually passes through his body.
Q.  Why are MEN sometimes MAIMED by lightning?




THUNDER.                 15
A. Because the electric fluid produces an action upon the nerves sufficient
to injure them, but not to destroy aife.
Q.  WThat is THUNDER?
A.  The noise made by the concussion
of the air when it closes again, after it
has been parted by the lightning flash.
A part of the noise is owing to certain physical and chermi-al changes produced in the air by the electric fluid.
Q.  Why does LIGHTNING part the air through
which it passes? it does not part a rod of iron.
A.  As iron is a conductor, it allows
the fluid to pass frieely over it; but air
(being a non-conductor) resists its passage.
Q.  WVhy is THUNDER sometimes ONE VAST
CRASH?
A.  Because  the  liughtning-cloud  is
near the earth; and as all the vibrations
of the air (on which  sound  depends)
reach the ear at the same moment, they
seem  like one vast sound.
Q.   Wichy is the PEAL sometimes an IRREGULARS
bm'oken ROAR?
A. Because the lightning-cloud is a
long way off; and as some of the vibrations of the air have muich further to
travel than others, they reach the ear at
different times, and produce a continuous
otund.




16                THUNDER.
Q.   Which vibrations will be soonest heard?
A.  Those produced in the lowest portions of the air.
Q.   Why will those vibratio.ns be heard FIRST,
which are made LAST?
A.  Because theflaslh (wlich pl)oduces
the sound) is almost instantaneouts, but
sound  takes a whole second of tinme to
travel 380 yards.
Q.  If a thunder-cloud were 1900 yards off,
how long, would the peal last?
A.  Five seconds: we shouldjirst hear
the vibrations produced in those portions
of the air contiguous  to the earth; then
those more remote; and  it would be 5
seconds before those vibrations reached
us, which were made in the immediate
vicinity of the cloud.
380 X 5 = 1900.
A popular method of telling how far the storm is off is
this-Imihnlediately you see the flash, put yolr lhand upon
your pulse, and count how many times it beats before you
hear the thunder: if it beats 6 pulsations, the storm is 1
mile off; if 12 pulsations, it is 2 miles off; and so on.
Q.   W'hy is the THUNDER sometimes like a deep
GROWL?
A.  Because the storm  isfar distant,
and the sound of the thunder indistinct.
Q.  Is not the sound of thunder affected by
LOCAL circumstances?
A.  Yes; theflatter the country, the
more  unbroken  the  peal.    MJLuntain




THUNDER-BOLTS.               17
scenery breaks the peal, and makes it
harsh and irregular.
Q.  W'hat is the cause of ROLLING TIHUNDESR?
A.  The vibrations of air (having diffferent lengths to travel) reach the ear at
successive intervals.
The reverberation (or echo) amongst the massive clouds
contributes in some measure to this effect.
Q.  WThy is a fiash of lightnin,r generally followed by POURING RAIN 2
A.  The flash  produces a change in
the physical condition oftthe air, rendering
it unable to hold so much water in solution as it could  before; in consequence
of which, a part is given off in heavy
rain.
Q.  TWhy is a flash of light4ning generalnily followed by a GUST OF WIND?
A.  Because the physical colndition of
the air is disturbed by the passage of the
lightning, and wind is the result of this
disturbance.
Q.   Wby is there NO THUNDER to what zs called
SUMMER LIGIITNING?
A. Because the lightning-clouds are.
sofar distant, that the sourul of the thui, —
der is lost, before it reaches the ear.
Q.  Do THUNDER-BOLTS ever drop from  thet
clouds?
A.  No; the notion of thlnder1-bolts




18             ELECTRICITY.
arises, either from the globular form
which lightning sometimes assumes; or
else  from  the  gaseous fire-balls, which
sometimes fall from the clouds.
See page 13.
Q.   Why is the THUNDER often several moments
ArTER the FLASH? 
A. Because it has a long w'ray to
come.  Lightning travels nearly a 7nillion tinres faster than thunder; if, therefore, the thunder has a long way to come,
it will not reach the earth, till a considerable title after the flash.
Q.   Can we not tell the DISTANCE of a thundercloud, by observing the interval which elapses between
the flash and the peal?
A.  Yes; the flash is instantaneous,*
out thunder will take a whole second of
time to travel 380 yards: hence, if the
flash  be 5  seconds before the thunder,
the cloud is 1900 yards off. (See note,
p. 16.)
i. e. 380 X 5 = 1900 yards.
Q.   Whlat rLACEs are most DANGEROUS during
-e STORM?
A. It is very dangerous to be near a
tree, or lofty building;  and  also to be
near a river, or any running water.
* The speed of lightning is so great, that it would go
480 times round the earth in one mihlute: whereas thundier would go scarcely 13 miles in the same space of time,




LIGHTNING.                 19
Q.   Why i; it DANGEROUS to be NEAR a TREE,
or lofty building, during a thunder-storm?
A.  Because a tall pointed object (like
a tree or spire) will fiequently discharge
a lightningc-cloud; and if any one were
standing  near, the  lightning  milghlt diverge firom  the tree, and  pass through
the fluids of the human body.
Q.  Hozw can a TREE or SPIRE DISCHARGE a
lightning-cloud?
A.  A  lightning-cloud  (floating  over
a plain) may be  too far off  to be discharged by it; but, as a tree or spire
would shorten this distance, it micght no
longer be too far off to be dischalrged.
For example. If a lightning-cloud were 7100 yards
above the earth, it would be too far off to be discharged:
but a tree or spire 50 yards high would make the cloud
only 650 yards oWf a conductor; in consequence of which,
the cloud would be instantly discharged.
Q.  Is not AIm a CONDUCTOR of lightzing?
A.  No; dry air is not a conductor of
lightningr.
Q.   T/ky /would lightning fly from a tree or
spire, into a MAN standing near?
A. Because the electric fluid (called
lightning) always chooses for its path the
best conductors; and, if the human fluids
proved the better conductor, would pass
throug'h the man standingc near the tree
rather than down the tree itself.




20             ELECTRICITY.
There would be no danger if the tree or spire were
made of metal; because metal is a better conductor than
the human fluids.
Q.  Does lightning go through the inside, or
down the OUTSIDE of a tree?
A.  It runs down the outside of' a tree;
but passes through tile inside of a nan.
Q.  Why does lightning pass down the OUTSIDE
of a tree?
A. Because it always makes choice
of the best conductors; and the outside
of a tree is a better conductor than the
inside.
Q.  Why does lightning pass throug,h the INSIDE of a man?
A.  Because the fluids of the human
bedy make a better conductor than the
skcin; therefore, lightning, passes through
a man, and not down his skin.
Q.   wfihy is it DANGEROUS to be?near a deep
RIVER, or any other running uwater, during a thunder-slorm?
A. Because running water is a good
conductor; and lightning always takes
in its course the best conductors.
Q.  Why is it dangerous for a man to be NEARP
WATER in a thunder-storm?
A. Because the height of a ntma1  may
be sufficient to discharge a cloud and
(if there were no taller object nigh) the




LIGHTNING.              21
lightninag mi(ght make the nzan its comductor to the water.
SIe note on p. 19.
Q.  Tr/hy is it DANGEROUS to RING CHURCH
BELLS during a thunder-storm?
A.  For two reasons: 1st-Because
the steeple may discharge the lightningcloud, merely firom its height; and
2dly-As the swinging of the bells
puts the air in nmotion, it diminishes its
resistance to the electric fluid.
Q.  Why is it unsafe to RUN or DRIVE FAST
during a thundler-storm?
A.  Because it produces a current of
air; and, as air in motion affords less
resistance to the flash, it is a better conductor than air iln a state of rest.
Q.  What PARTS of a DWELLING are most DANGEROUS during a thunder-storm?
A. The fire-place, especially if the
fire be lighted; the attics and cellar. It
is also imprudent to sit close by the
walls, to ring the bell, or to bar the shutters, during a thunder-storm.
Q.  WT/,y is it DANGEROUS to sit BEFORE A
FIRE during a thunder-storm?
A. Because the heated air and soot
are conductors of lighlltning; especially
when  connected  with  such  excellent




t'2           ELECTRICITY.
conductors as the stove, fender and fireIrons.
Q.  T/iy are ATTICS and CELLARS more DANGEROUS in a cthunder-storm, than the middle story
of a house?
A. Because lightning sometimes passesfr-om the clouds to the earth, and sometimes front the earth to the clouds; in
either cases the middle story would be
the safer place.
Q.  WVhen does lightning pass FROM  THE
EARTH to the CLOUDS?
A.  When the clouds are in a "negative" state of electricity.
Q.  WThen does lightning pass FROM  THE
CLOUDS to the EARTH?
A. When the clouds are in a " positive" state of electricity.
Q.  What is meant by the clouds being in a
"positive state of electricity?"
A.  When the clouds contain  more
electric fluid than they generally do, they
are said to be in a " positive state of electricity."
Q.  What is meant by the clouds being in a
" ne-gative state of electricity?"
A.  When  the  clouds  contain  less
electric fluid than they ought to do, they
are said to be in a "negative state of
electricity."




LIGHTNING.                 23
Q. Does the flash proceed firom a negative or
POSLTI E body?
A. Always from a positive body;
that is, from one over-charged with elec.
tric fluid.
It is generally thought that there are two worts of electricity, one called VITREOUS, corresponding to positive electricity; and the other called RESINOUS, corresponding to
negative electricity.
Q.   Wthen lightning flashesfrom the earth to
the clouds. what is the flash called?
A.  It is popularly called the "returning stroke;" because the earth (being
over-charged with electric fluid) returns
the surplus quantity to the clouds.
Q.   Why is it DANGEROUS to lean AGAINST A
WALL during a thunder-storm?
A. Because the electric fluid will
sometimes run down a wall; and (as a
man is a better conductor than a  vall)
would leave the wall, and run down the
man.
Q.    thy is it dangerous to RING a BELL dur.
ing a thunder-storm?
A.  Bell-wire  is an excellent  conductor; and (if a person were to touch the
bell-handle) the  electric  fluid, passing
down  the wire, might run throughll his
hand and injure it.
Q.   Why would the lightning run through a
man touching a bell-handle?




24            ELECTRICITY.
A. Because the human body is a
better conductor than the wall (between
the bell-handle and the floor); and as
lightning always chooses the best conductor for its path, it would (in this case)
pass through the man, and injure him.
Q'Why is it DANGEROUS to BAr, a SIIUTTER
during a thunder-storm?
A.  Because the iron shutter-bar is an
excellent conduZctor; and the electric fluid
mi'ght run from the bar throulgh the person touching it, and injure hllim.
Q.  VWhy is it dangerous to be zn a CROWD
during a thunder-sterm?
A. For two reasons: 1st-Because
a mass of people forms a better conductor
than an individual; and
2dly-Because the vapor arising from
a crowd increases its conducting power.
Q.  TVhy is a MASS of bodies a better conductor
than a single body?
A.  Each living body is a conductor
of electricity; and a connected mnass of
such conductors is more likely to  be
struck, than a single individuttl.
Q    WV7y is the danger increased by the vAPon
which rises from a crowd?
A. Because vawpor is a conductor,
and the more conductors there are, the
greater the danger will be.
b-~IIV  IIV  HII




LIGHTNING.             25
Q.  Why. is a THEATRE dangerous during a
thunder-storm?
A. Because the crowd, and great vapor arisingf from  so many livingc bodies,
render it an excellent conductor of lightnling.
Q.  Why is a FLOCK of sheep in greater dan
ger than a smaller number?
A.  1st-Because each sheep is a conductor of lightning, and the conducting
power of the fock is increased by its
numbers: and
2dly-The very vapor arisirong from  a
flock of sheep increases its conducting
power, and its danger.
Q.  Why is a HERD of cattle in danger during
a storm?
A. ist —Because the number of living
bodies increases the conducting power
of their animal fluids  and
2dly-The very vapor arising from a
herd increases its conducting power.
Q.  If a person be ABROAD in a thunder-storm,
what place is the SAFEST?
A. Any place about 20 or 30 feet
from some tall tree or building; except
it be near to running water.
Q.  Why would it be safe to stand 20 ot 30
feet from some tall tree, in a thundler-storm?
A. Because the liohtning would al.
2




ci0e          ELECTRICITY.
ways choose the tall tree as a conductor;
and we should not be sufficiently near
the tree, for the lightning to diverge front
it to us.
Q.  If a person be in A CARRIAGE in a thunder-storm, in wehat way can he travel most SAFELY?
A.  He should not lean against the
carriage; but sit upright, without touching any of the four sides.
Q.  lW'hy should not a person lean AGAINST the
carriage in a storm?
A. Because the electric fluid might
run down the sides of the carriage; and
(if a person were leaning against them)
would make choice of him for a conductor, and perhaps destroy life.
Q.  If a person be in A HOUSE during a thunder-storm, what place is SAFEST?
A. Any room in the middle story.
The middle of the room is best; especially if you place yourself on a mattress, b)ed, or hearth-rug.
Q.  Why is the MIDDLE STORY of a house SAtmrST in a thunder-storm?
A. Because the fluid (if it struck the
o.use at all) would be diffused among
the several conductors of the ulpper part
of the house, before it reached the middie story; in consequence of which, its
force would be weakened.




LIGHTNING.              27
Q.   TWhy is the MIDDLE of the ROOM more SAFE
than any other part of it, in a thunder-storm?
A.  Because the lightning (if it struck
the room at all) would come down the
chimney, or walls of the room; and,
therefore, the fulrther distant from these,
the better.
Q.  Why is a MATTRESS, BED, or HEARTII-RUO
a good security against injury from lightning?
A.  Because they are all non-conductors; and, as lightning  always makes
choice of the best conductors, it would
not choose for its path such thinlgs as
these.
Q.  Is it better to be WET or dry during a
storm?
A. To be iwet: if a person be in the
open field, the best thing he can do, is
to stand about 20 feet fiom some tree,
and get completely drenched to the skin.
Q.  Why is it better to be WET than dry?
A. Because twet clothes form a better
conductor than the fluids of our body;
and, therefore, liglltning would pass
down our wet clothes, without touching
ou' body at all.
Q.  What is the SAFEST thing a person can do,
to avoid injuryfrom lightning?
A   He should  draw  his bedstead
ato  the middle of the room, commit




28             ELECTRICITY.
himself to the care of God, and go to
bed; remembering that our Lord has
said, " The very hairs of your head are
all nurmbered."
N. B. No great danger needs really to be apprehended
from lightning, if you avoid taking your position near tall
trees, spires, or other elevated objects.
Q.  What is a LIGHTNING-CONDUCTOR?
A.  A  metal rod fixed in the earth,
runninc   up the whole height of a building, and risinog in a point above it.
Q.   What metal is the best for this purpose?
A.  Copper makes the best conductor.
Q.   Why is COPPER better than iron?
A.  1st-Because copper is a better
conductor than iron:
2dly-It is not so  easily fused  or
melted: and
3dly-It is not so much injured by
weather.
Q.   What is the USE of a lightning-conductor?
A. As metal is a most excellent conductor, lightning (which makes choice
of the best conductors) will run down a
metal rod, rather than the walls of the
building.
Q.  How FAR will the beneficial influence of a
6sghtning-conductor extend?
A.  It will protect a space all round,




tIGHTNING.               29
4 times the length of that part of the rod
which rises above the building.
Q.  Give me an example.
A. If the rod rise 2 feet above the
house, it will protect the building for (at
least) 8 feet all round.
Q.  Wlhy are not lightning-condiactors more
generally used?
A. Because many accidents have
arisen from conductors of defective construction.
Q.  Howl can', lightning-conductors be productive of HARM?
A. If the rod be broken by weather
or accident, the  electric  fluid  (being
obstructed in its patll) will damage the
building.
Q.  Is there any other evil to be apprehended
from a lightning-rod?
A.  Yes; if the rod be not big enough
to conduct the vwhole current to the earth,
the lightning will fuse the metal, and
injure the building.
The conducting rod should be (at least) one inch in diameter.
Q.  How does LIGHTNING  sometimes KNOCK
DOWN HOUSES and churches?
A. The steeple or chimney is first
struck; the lightningr then darts to the
iron bars and cramps, employed in the




so              ELECTRICITY.
building; and (as it darts from bar to
bar) shatters to  atoms  the  bricks  and
stones which oppose its progress.
Q.   Can you tell ime how St. Bride's Church
(London) was nearly destroyed by lightning, about
100 years ago?
A.  The  lightning  first  struck  the
metal vane, and ran down the rod; it
then darted to the iron cramps, employed
to support the building; and (as it flew
from bar to bar) smashed the stones of
the church which lay between.
Q.   Why did the lightning fly about from
place to place, and not pass down in a straight
course?
A. Because it always takes in its
course the best conductors; and will fly
both  rioht and  left, in  order to reach
them.
Q.   Why does LIGHTNING turn milk souR?
A.  Lightning causes the gases of the
air (through which it passes) to combine,
and thus produces a poison, called nitric
acid; some small portion of which, mixing with the milk, turns it sour.*
* The air is composed of tw,) gases, called oxygen and
nitrogen, mized together, but?oot combined. Oxygen cornbired with nitrogen, produces five deadly poiso;is, viz.nitrous oxide, nitric oxide, hyponitrous acid, nitrous acid,
and nitric acid, according to the proportion of each gas in
the combination.




K. B. Sometimes the lwere heat of the air, during the
storm, turns milk sour.
Q.  What is the difference between COMBINING
and MIXING?
A. When different ingredients are
mingled together iwithout undergoing any
chemical change, they are  said  to be
mixed; but when the natural properties
of each are altered by the union, then those
ingredients are said to be combined.
Q.  Give me an example.
A.  Different colored sands (shakento-,ether in a bottle) will mix together, but
ot combine: but water poured on quicklime, will comzbine with the lime, and not
mix with it.
Q. WZhy are diferent grains of sand said t.
be MInXED, when they are shaken together?
A.  Because (though mingled tog(eth
er) the property of each grain remains
the same as it teas before.
Q.  7Ithy is water, poured on lime, said to
COMBINE with it?
A. Becalse the properties of each
are altered by the mixture; the lime alters theclharacter of the water, and the
water that of the lime.
Q.  Do oxygen and nitrogen COMBINE: or only
Mix together, in common atmospheric air?
A.  They only nmix together, as grains
-LIJ  V-I'~VYV~V




32           ELECTRICITY.
of sand would do when shaken in a but.
tie. When oxygen and nitrogen cotn.
bine, they do not constitute air, but acid
poisons.  (ASee note on p. 30.)
Q. Why does LIGHTNING turn BEER SOUR, al.
though contained in a close cask?
A.  Because, if beer be new and the
process of fermentation incomplete, lightninf will so accelerate the process, as to
turn the sugar into acetic acid at once,
without'passing through the interinediate state of al'cohol.
Q.  Why is NOT OLD beer and strong PORTER
made soUR by lightning?
A.  Because thefermentation is more
complete; and, therefore, is less affected
by electrical influence.
Q.'Why is METAL sometimes FUSED by light
ning?
A. Because the dimension of the
metal is too small to afford a path for the
electric current.
Q. Why does LIGHTNING PURIFY the AIR?
A.  For two reasons: 1st-Because
the electric fluid produces " nitric acid"
in its passage through the air
2dly-Because the agitation of the
storm stirs up the air.




LIGHTNING.                 33
The " nitric acid " is produced by the conbiuztlion of
some portions of the oxygen and nitrogen of the air.*
Q.  How does the prod uclion of nitric acid PURlFY t,e air?
A.. Nitric acid acts very powerfully
in destroying the exhalations, which arise
from putrid vegetable and animal matters.
Q.   WAhy is LIGHTNING more common in sumMER arnd in AUTUMN, than in springo and winter?
A. Because the heat of summer and
autumn produces great evaporation; and
the conversion of water into vapor always
developes electricity.
Q.   Why does a THUNDER-STOR.I  generally foalow very dry weather?
A. Because dry air (being a nonconductor) will not relieve the clouds of
their electricity; so the fluid accumulates,
till the clouds are discharged in a storm.
Q.   Why does a THUNDER-STORM rarely succeed WrET weather?
A. Because nmoist air or falling rain
(being  a conductor) carries down  the
electric fluid gradually and silently to
the earth.
Q.   What is the general DIRECTION of a TrII/U
DEIR-STORM?
* The oxygen and nitrogen are not combined, but simply
mixed, in the ordinary nir; but lightning causes some
portions of the mixed eletnauts to combine. See note, p. 30.




34            ELECTRICITY.
A. Either from east to west; oi from
north to south.
Q.  Why is ELECTRICITY excited by FRICTION?
A. Electricity, like heat, exists in all
matter; but is often in a latent state:
friction disturbs it, and brines it into
active operation.
" Latent," see p. 87.
Q.  Wlhy is a TREE sometimes SCORCHED by
lightning, as if it had been set on fire?
A. Lightning scorches by its own
positive heat, just the same as fire would.
Q.  Why is the BARK of a TREE often ripped
Autite of by a flash of lightning?
A. Because the latent heat of the
tree (being very rapidly developed by
the electric fluid) forces away the bark
in its impetuosity to escape.
Some part of this is probably due to the simple mechan.
icalforce of the lightning.
Q.  Why are BOUGHS of TREES broken of by
lightning?
A. Because the mechanical force of
lightning  is very  great; and, as  the
boughs of a tree are imperfect condluctors, they will often be broken off by this
force.
Q.  Why is an electric shock felt MOST at the
~ELBOW JOINT?
A. Because the path of the fluid is




LIGHTNING.                35
obstructed by the joint; and the shock
(felt at the elbow) is caused by the fluid
leaping from  one bone to another.
Q.  Is electricity accompanied with any ODOR 
A.  Yes; near a large electrical machine in good action, there is always a
peculiar odor, resembling  sulphur' and
phos)phorus; this odor is called " OZONE."
Pronounce O-ZONE, in two syllables.
Q.  Has this peculiar odor, called " OZONE,"
been observed in thunder-storms?
A.  Yes;  sotnetiim-es the sulphurous
odor prevails, and sometimes the phosphoric.
If the gaseous body disengaged by lightning, reaches us
in a concentratea form, the odor is SULPHUROUS; if in a
diluted form, it is PHOSPHORIC.
Q.   What are FUL'GURITES?
A. Hollow tubes produced in sandy
soils by the action of lightning.
Q.  How does lightning produce fiulgurites?
A. When it enters the earth, it fuses
the flinty matter of the soil into a vitreous (or glassy) substance, called a fulgurite.
Q. Does not lightning sometimes affect the
tharacter of IRON and STEEL?
A. Yes; bars of iron and steel are
sometimes rendered  magnetic by licrhtning.




36         CHEMICAL ACTION.
Q. Give, me an instance of the magnctw effect
of lightning.
A. Sometimes it will reverse the magnetic needles of the electric telegraph,
and sometimes destroy their magnetism
altogether.
Q.  What is meant by the magnetic needles
being REVERSED?
A. That part of the needle which
ought to point toward the northl, is made
to point toward the south; and that part
which ought to point south, is made to
point toward the north.
Q.  How does ligkhtning act upon the magnetiz
needles of the electric telegraph?
A. The electric fluid is conveyed
along the conductino, wires to the telegraphic needles.
CHEMICAL ACTION.
CHAPTERP III.
Q. What is the THIRD chief source of heat?
A.  CHEMICAL ACTION.
Q.  Whfat is meant by chemical action being
the source of heat?
A.  Many things, when theirchemical
constitution is changed (either by the




LATENT HEAT.                 37
abstraction of some of their gases, or by
the combination of others not before united) evolve heat, while the change is going on.
Q.  Explain by illustration what you mean.
A. Water is cold, and sulphuric acid
is cold; but if these two cold liquids be
mixed together, they will produce intense
heat.
Q.   W7iy does COLD WATER, poured on LIME,
make it intensely HOT?
A. Because heat is evolved by the
chemical action which takes place, when
the cold water combines with the lime.
N. B. Heat is always evolved, when a fluid is converted
Into a solid form. Heat is always absorbed, when a solid is
changed into a liquid state. As the water is changed from
its liquid form when it is taken up by the lime, therefore,
heat is given off.
Q.   Where does the heat come from?
A. It was in the water and lime before; but was in a latent state.
Q.   Was there heat in the cold water an4 Dime,
before they were mixed together?
A. Yes. All bodies contain heat;
the coldest ice, as well as the hottest fire.
Q.  Is there HEAT even in ICE?
A. Yes; but it is latent (i. e., not per.
ceptible to our senses.)
Latert, from the Latin word Lateo, (to lie hid.)




38            CHEMICAL ACTION.
Q.   How do you KNOW  there is heat, if you
cannot PERCEIVE it?
A.  Thus:-Ice  is  32~ by  the  thern
rinometer; but if ice be melted over a fire,
(though 140~ of heat are absorbed by the
process,) it will feel no hotter than before.
i. e., it will be only 320, and not 1720.*
Q.   WTrhat becomes of the 140~ which went into
the ice to melt it?
A. It is hidden in the water; or (to
speak more scientifically) it is stored up
in a latent state.
Q.   flow MUCH heat may be thus secreted or
made latent?
A. All things contain a vast quantity
of latent heat; but as much as 11400 of
heat may remain latent in water.
Q.   Iiow can 1140~ of heat be added to water,
without being perceptible to our feelings?
A. lst-1400 of heat are hidden in
water, when ice is melted by the sun or
fire.
2dly —10000 more of heat are secreted, when water is converted into steam.
Thus, before ice is converted into steam,
1140~ of heat become latent.
One pint of boiling water, (2120 according to the ther.
mometer,) will make 1800 pints of steam; but the steam
is no hotter to the touch than boiling water-both are
212~; therefore, when water is converted into steam, 10003
* 320, i. e., 82 degrees; 140o, i. e., 140 degrees, &c.




COMBUSTION.              39
of heat become latent. HIence, before ice is converted
into steam, it must contain 1140~ of latent heat.
Q.  Can we be made to FEEL the heat of ICE or
snow?
A. Yes. Into a pint of snow put half
as much salt; then plunge your hands
into the liquid; and it will feel so intensely cold, that the snow itself will
seem warmn in comparison to it.
Q.  Is SALT and SNOW really COLDER than
snow?
A. Yes, many degrees; and by dipping your hand into the mixture first,
and into snow afterward, the snow will
seem to be comparatively warm.
CHAPTER IV.
COMBUSTION.
Q.  Wrhat is FIRE 
A. Heat and light, produced by the
combustion of inflammable substances.
Q.  How is HEAT evolved by combustion?
A.  By chemical action. As latent heat
is liberated, when water is poured upon
lime, by chemical action; so latent heat
is liberated in combustion, by chemical
action also.




40          CHEMICAL ACTION.
Q. What CHEMICAL ACTION takcs Jplace $s
combustion?
A. The elements of the fuel combine
with the oxygen of the air.
Q. What is meant by the " ELEMENTS OF FUEL?"
A. As bread is a compound of flour,
yeast, and salt; so fuel is a compound
of hydrogen and carbon.
Q.  What are the ELEMENTS of atmospheric AIR?
A.  Oxygen and nitrogen, mixed together in  the following  proportions;  4
gallons of nitrogen and one of oxygen
will make 5 gallons of common air.
Q.  What is CARBON?
A. The solid part of fuel. Carbon
abounds in all animal bodies, earths, and
even in some minerals.
Q.  Mention some different species of CARBON.
A. Common charcoal, lamp-black,
coke, and the diamond.
Q.  What is HYDROGEN?
A. An inflammable gas. The gas
used in our streets is hydrogen driven
out of coals by heat.
Coal gas (more correctly speaking) is carburetted hy.
drogen, i. e., carbon and hydrogen. See p. 262.
Q.  What are the peculiar characteristics of
hydrogen gas?
A. 1st-It is the lightest of all known
substances:




COMBUSTION.                   41
2dly —t will burn immnediately it is
ignited: and
3dly-A  lighted candle (immersed  in
this gas) will be instantly extinguished.*
Q.   What is OXYGEN 
A. A gas, much heavier than hydrogen; it gives brilliancy to flame, and is
essential to animal life.t
* Hydrogen gas may be made thus: —Put some pieces
of zinc or iron filings into a glass: pour over them a little
sulphuric acid (vitriol)' diluted with twice the quantity
of water; then cover Lhe glass over for a few minutes
and hydrogen gas will be given off.
EXPERIMENTS.
If a flame be put into the glass, an EXPLOSION will be
made.
If the experiment be tried in a phial, which has a piece
of tobacco-pipe run through the cork, and a light held a
few moments to the top of a pipe, a FLAMPE will be made.
If a balloon be held over the phial, (so that the gas can
inflate it,) the balloon will ascend in a very few minutes.
t Oxygen gas is much more troublesome to make than
hydrogen. The cheapest plan is to put a few ounce of
manganese (called the black oxide of manganese) into an
iron bottle, furnished with a bent tube; set the bottle on
a fire till it becomes red hot, and put the end of the tube
into a pan of water. In a few minutes, bubbles will rise
through the water; these bubbles are oxygen gas.
These bubbles may be collected thus:-Fill-a common
bottle with water; hold it inverted over the bubbles which
rise through the pan, but be sure the mouth of the bottle
be held in the water. As the bubbles rise into the bottle.
the water will run out; and when all the water has run
out, the bottle is full of gas. Cork the bottle while the
mouth rem.ains under water; set the bottle on its base;
cover the cork with lard or wax, and the gas will keep,
till it be wanted.
N. B. The quixkest way of making oxygen gas, is to
rub together in a mortar half an ounce of oxide of copper




42           CHEMICAL ACTION.
Q.   What is NITROGEN?
A. An invisible gas, which abounds
in animal and vegetable substances. The
following are its peculiar characteristics:
1. It will not burn;
2. An animal cannot live in it;
3. It is the principal ingredient in
common air.*
Nearly 4 gallons out of every 5 being nitrogen gas.
and half an ounce of chlorate of potassa. Put the mixture into a common oil flask, furnished with a cork which
has a bent tube thrust through it. Heat the bottom of
the flask over a candle or lamp; and when the mixture is
red hot, oxygen gas will be given off. Note-the tube
must be immersed in a pan of water, and the gas collected
as before.
(Chloride of potassa may be bought at any chemist's;
and oxide of copper may be procured by heating a sheet
of copper red hot, and when cool, striking it with a hamraer; the scales that peel off, are oxide of copper.)
EXP. Put a piece of red hot charcoal (fixed to a bit of
wire) into your bottle of oxygen gas; and it will throw
out most dazzling sparks of light.
Blow a candle out; and while the wick is still red, hold
the candle (by a piece of wire) in the bottle of oxygen
gas; the wick will instantly ignite, and burn brilliantly.
(Burning sulphur emits a blue flame, when immersed
in oxygen gas.)
* Nitrogen gas may easily be obtained thus:-Put a
piece of burning phosphorus on a little stand, in a plate
of water; and cover a bell glass over it. (Be sure the
edge of the glass stands in the water.) In a few minutes
the oxygen of the air will be taken up by the burning
phosphorus; and nitrogen alone will be left in the bell
glass.
(N. B. The white fume, which will arise and be absorbed
by the water in this experiment, is phosphoric acid; i. e.
phosph orus combined with oxygen of the air.)




COMBUSTION;             43
Q.  Why is there so MUCH nitrogen in the air?
A. In order to dilute the oxygen.
If' the oxygen were not thus diluted,
fires would burn out too quickly, and
life would be too rapidly exhausted.
Q.  What three elements are necessary to pre.
duce COMBUSTION?
A. Hydrogen gas, carbon, and oxygen
gas: The two former in thefuel; and the
last in the air, which surrounds the fuel.
Q.  What causes the combustion of the fuel?
A. The hydrogen gas of the fuel
(being set free, and excited by a match),
unites with the oxygen of the air, and
makes a yellow flame; this flame heats
the carbon of the fuel, which (also uniting
with oxygen of the air) produces carbonic acid gas.
Q.  What is CARBONIC ACID GAS?
A. Only carbon (or charcoal) combined with oxygen gas.
Q.  Why does FIRE produce HEAT?
A. Because it liberates latent heat
from the air and fuel.
Q.  What CHEMICAL CHANGES in air and fuel
are produced by COMBUSTION?
A. 1st —Some of the oxygen of the
air, combining with the hydrogen of the
fuel, condenses into water: and




14         CHEMICAL ACTION.
2dly —Some of the oxygen of the air
combining with the carbon of the fuel,
forms carbonic acid gas.
Q.  Why is a FIRE (after it has been lang
burning) r~ED HOT?
A.  Because the whole surface of the
coals is so thoroughly heated, that every
part of it is undergoing a rapid union
with the oxygen of the air.
Q.  In a BLAZING fire, w/hy is the UPPER surface of the COALS BLACK, and the LOWER surface RED?
A. Because carbon (being solid) requires a great degree of heat to make it
unite with  the oxygen of the air.  In
consequence of which, the hot under
surface of coals is frequently red from its
union with oxygen, while the cold upper
surface remains black.
Q.  Which burns the more quickly, a BLAZING
fire, or a RED HOT one?
A. Fuel burns quickest in a blazing
fire.
Q.  Wrhy do BLAZING COALS BURN QUICKER
than red hot ones?
A. Because the inflammable gases of
the fuel (which are then escaping) greatly assist the process of combustion.
Q.  Why do the coals of a CLEAR BRIGHT fire
durn out more slowly than blazing coals?
A.  Because rmyost of the iafltamwnable




COMBUSTION.              45
gases, and much of the solid fuel, have
been consumed already; so that there
is less food for combustion.
Q.  What is SMOKE?
A.  Unconsumed parts of fuel (principally carbon) separated from the solid
mass, and carried up the chimney by
currents of hot air.
Q.  WVhy is there MORE SMOKE when COALS are
FRESH added, than when they are red hot?
A. Because carbon (being solid) requires a great degree of heat to make it
unite with oxygen, (or, in other words, to
bring it into a state of perfect combustion:)
when coals are fresh laid on, more carbon
is separated than can be reduced to combustion, and the surplus flies off in smoke.
Q.  Why is there so LITTLE SMOKE with a RED
HOT FIRE?
A. Because the entire surface of the
coals is in a state of combustion; and, as
very little carbon remains unconsumed,
there is but little smoke.
Q.  Why are there DARK and BRIGHT SPOTS in
a CLEAR cinder FIRE?
A. Because the intensity of the combustion is greater in some parts of the
fire, than it is in others.
Q.  Why is the intensity of the combustion so
UNEQUJI.?




46         CHEMICAL ACTION.
A. Because the air flies to the fire in
various and unequal currents.
Q.  Why do we see all sorts of GRLOTESQUE
FIGURES in hot COALS?
A. Because the intensity of combustion is unequal, (owing to the gusty
manner in which the air flies to the fuel:)
and the various shades of red, yellow,
and white heat (mingling with the black
of the unburnt coal), produce strange
and fanciful resemblances.
Q.  Why does PAPER BURN more readily than
wood?
A. Because it is of a more fragile
texture; and, therefore, its component
parts are more easily heated.
Q.  Why does WOOD BURN more readily than
coal?
A. Because it is not so solid; and,
therefore, its elemental parts are more
easily separated, and made hot.
Q.  When a FIrE is LIGHTED, hy is PAPER
laid at the BOTTOM, against the grate?
A. Because paper (in consequence
of its fragile texture) very readily catches
fire.
Q.  Why is WOOD laid on the top of the paper?
A.  Because wood (being more subtacntial) burns longer than paper; and}




COMBUSTION.             47
therefore, affords a longer contact of
flamne to heat the coals.
Q.  Why would not paper do WITHOUT mUod?
A. Because paper burns out so rap.
idly, that it would not afford sufficient
contact offfaine to heat the coals to com.
bustion.
Q.  Why will not wood do WITHOUT shavings;
straw, or paper?
A. Because wood is too substantial
to be heated into combustion by the feeble flame issuing from a match.
Q.  Why would not the paper do as well, if
placed on the TOP of the coals?
A.  Because every blaze tends upward; if, therefore, the paper were
placed on the top of the coals its blaze
would afford no contact of flame to the
fuel lying below.
Q.  Why should COAL be placed ABOVE the wood?
A. Because otherwise, the flame of
the fuel would rnot rise through the coal,
to heat it.
Q.  Why is a FIRE KINDLED at the LOWEST
BAR of a grate?
A. That the flame may ascend
through the fuel, to heat it. If the fire
were kindled from  the top, the flame
would not come in contact with the fue
placed below.




48         CHEMICAL ACTION.
Q.  Why does COAL make such EXCELLENT
FUEL!
A. Because it contains a large
amount of carbon and hydrogen gas, in a
very compact and convenient form.
Q.  Why will CINDERS become RED HOT more
quickly than COALS?
A. Because they are sooner reduced
to a state of combustion, as they are
more porous and less solid.
Q.  WM'y will not IRON CINDERS burn?
A. Because they contain impurities,
which are not so ready to combine with
oxygen, as carbon and hydrogen are.
Q.  Why are CINDERS lighter than COALS?
A. Because they are full of little
holes; from which vapor, gases, and
other volatile parts, have been driven
off by previous combustion.
Q.  Why will not STONES do for fuel as well as
COALS?
A. Because they contain no hydrogen,
and little or no carbon.
Q. Why will not WET KINDLING light afire?
A. 1st-Because the moisture of the
wet kindling prevents the oxygen of the
air from getting to the fuel; and
2dly —The heat of the fire is perpetually drawn off, by the conversion of water
into steam.




COMBUSTION.             49
Q.  Why does DRY wood burn BETTER than
GREEN?
A. 1st-Because none of its heat is
carried away by the conversion of water
into steam; and
2dly-The pores of dry wood (being
filled with air) supply the fire with
oxygen.
Q.  Why do TWO pieces of WOOD burn BETTER
than ONE?
A. 1st-Because they help to entangle the heat of the passing smoke, and
throw it on thefuel; and
2dly-The air, impinging against the
pieces of wood, is thrown upon the fire
in a kind of eddy or draught.
Q.  Why does SALT CRACKLE, when thrown
into a FIRE?
A. Salt contains water; and the
crackling of the salt is owing to the sudden conversion of this water into steam.
Q. Why will not wood or paper burn if steepea
in a solution of POTASH, phosphate of LIME, or AMMONIA (hartshorn)?
A.  Because any "al'kali" (such as
potash) will arrest the hydrogen which
escapes from the fuel, and prevent its
combination with the oxygen of air.
Q.  What ss an al'kali?
A. The con'verse of an acid: as
3




50         CHEMICAL ACTION.
bitter is the con verse of sweet, or insipid
the con'verlse of pungent.
Q.  Why does a JET Of FLAME sometimes burst
into the room THROUGH THE BARS OF A STOVE?
A. Because the iron bars conduct
heat to the interior of some lump of coal;
and its volatile gas (bursting through
the weakest part) is kindled by the
glowing coals over which it passes.
Q.  Why is this JET sometimes of a GREENISH
YELLOW color?
A. Either because some lump of coal
lies over the hot bars; or else the coals
below it are not red hot: in consequence
of which, some of the gas escapes unburnt,
and is of a greenish color.
Q.  Why does the gas escape UNBURNT?
A. Because neither the bars, nor
coals over which it passes, are red hot.
Q.  Why does a BLUISH FLAME sometimes flicker
on the surface of hot cinders?
A. Because the gas fromn the hot coals
at the bottom of the grate, mixing with
the carbon of the cc als above, produces an
inflammable gas (called carbonic oxide),
which burns with a blue flame.
Q.  Why is the FLAME of a good fire YELLOW?
A. Because both the hydrogen and
carbon of the fuel are in a state of perjt c




COMBUSTION.                51
comnbustion.  It is the white heat of the
carbon, which gives the pale yellow tinge
to the flaming' hydrogen.
Q.   What is LIGHT?
A.  Rapid undnlations of a fluid called
ether, striking on the eye.
Q.  How does COMBUSTION make these undulations of LTGHT?
A. Tile atoms of matter (set in motion by heat) striking against this ether,
produce undulations in  it; as a stone
thrown into a stream, produces undulations in the water.
Q.  How can UNDULATIONS of ether produce
LIGHT?
A.  As sound is produced by undulations of air striking on the ear; so light
is produced by undulations of ether striking on the eye.
Q.   WhatI/    is ETHER?
A. A very subtle fluid, which pervades and surrounds everything we see.
N. B. This theory of LIGHT is not altogether satisfactory;
but has been retained, as the most plausible hitherto projected.
Q. Does HEAT ALWAYS produce LIGHT?
A. No; the heat of a stack of hay,
or reeking  dunghill, though  very great,
is not sufficient to produce light.
Q.  Why is a YELLOW FLAME brighter than a
&ED IIOT COAL?




52         CHEMICAL ACTION.
A. Because yellow rays produce the
greatest amount of light, though red rays
produce the greatest amount of heat.
Q.  Why is the LIGHIT of a fire MORE INTENSE
sometimes than it is at others?
A.  The intensity of fire-light depends
upon the whiteness to which the carbon
is reduced by combustion. If carbon
be white hot, its combustion is perfect,
and the light intense; if not, the light is
obscured by smoke.
Q. Why will not CINDERS BLAZE, as well as
FRESH coals?
A. The fame of coals is made chiefly
by hydrogen gas.  As soon as this gas
has been consumed, the hot cinders produce only a gas, called carbonic acid,
which is neither luminous nor visible.
Q.  Where does the hydrogen gas of afire come
from?
A. All fuel is composed of carbon and
hydrogen gas, which are separated from
each other by the process of combustion.
(See p. 40.)
Q.  Why does not a FIRE BLAZE on a FROSTY
NIGHT, so long as it does upon another night?
A.  1st-Because  air condensed by
the cold contains more oxygen than the
same quantity of warmer air; and




COMBUSTION.             53
2dly-Air condensed by the cold is
heavier.  In consequence of which, it
falls more quickly on the fire, to supply
the place of the hot ascending air.
Q.'7rAy does a FIRE burn CLEAREST On a
FROSTY nught?
A. Because the volatile gases are
more quickly consumed; and the solid
carbon is plentifully supplied with oxygen
from the air, to make it burn brightly
and intensely.
Q.  Why does a FIRE burn more intensely in
WINTER than in~ SUMMER? 
A. Because the air is colder in winter,
than it is in summer.
Q.  Why does the COLDNESS of the air increase
the HEAT of a fire?
A.  Ist-Because air condensed by
the cold, supplies more oxygen than a
similar volume of warmer air; and
2dly-Condensed  air, being  heavy,
falls more rapidly into the place of the
hot ascending air, to supply the fire with
nourishment.
Q.  Why does the SUN, shining on a FIRE malk
it DULL; and often put it out?
A. 1st-Because the air (being rare.
fled by the sunshine) flows more slowly
to thie fire; and




54          CHEMICAL ACTION.
2dly-Even that which reaches the
fire, affords less nourishmtent.
Sunshine produces also some chemical ejfect upon the
air or fuel detrimental to combustion.
Q.   Why does the airflow to thefire more TARDILY for being RAREFIED?
A. Because the greater the contrast
(between the external air and that owhich
has been heated by the fire), the more rapid
will be the current of air toward that fire.
Q.  TW-hy does rarefied air afford LESS NOURISHMENT to fire than cold air?
A.  Because rarefied air contains less
oxygen than the same quantity of condensed air.
Inasmuch as the same quantity of oxygen is diffused
over a larger volume of air.
Q.  llhy does a FIRE burn more fiercely in the
OPEN AIR?
A.  1st-Because the air out-of-doors
is more dense than the air in-doors; and
2dly-It has freer access to the fire.
Q.   Why is the air out-of-doors more DENSE
than that in-doors?
A. Because it has freer circulation;
and, as soon as any portion has been
rarefied, it instantly escapes, and is supplied by colder currents.
Q.   Why does not a FIRE burn so freely in a
rHAW as in a FROST?




COMBUSTION.              55
A. Because the air is laden with
vapor; in consequence of which, it both
moves too slowly, and is too much rarefied
to nourish the fire.
Q.  Why does a FIRE burn so fiercely inl WINDY
weather?
A.  Because  the  air is so rapidly
changed, and affords plentiful nourishment to the fire.
Q.  Why does a pair of BELLOWS get a fire up?
A.  Because it drives the air more rapidly to the fire e; and the plentiful supply
of oxygen soon makes the fire burn intensely.
Q.  Why is theflame of a CANDLE EXTINGUISHED
when blown by the breath; and not made more intense like a fire?
A.  Because the flame of a candle is
confined to a very small wrick, firom which
it is severed by the breath; and (being
unsupported) must go out.
Q.  Why is a SMOULDERING WICK sometimes
RE-KINDLED by blowing it?
A. Because air is carried to it by the
breath with great rapidity; and the oxygen of the air kindles the red hot twick,
as it would kindle charred wood.
Q.  Why is not the red hot wick kindled by the
~ir AROUND it, without BLOWING?
A. Because oxygen is not supplied




56          CHEMICAL ACTION.
with sufficient freedom, unless air be
blown to the wick.
Q.  When is this experiment most likely to suc.
reed?
A.  In frosty weather; because the
air contains more oxygen when it is
condensed by the cold.
Q.   Why does a POKER LAID ACROSS a dull
FIRE revive it?
A.  For two reasons; ist-Because
the  poker  concentrates the  hcat, and
therefore increases it; and
2dly —Air is arrested in the narrow
aperture  between  the  poker and  the
coals, and a dratught  created.
See p. 49.
Q.   Why are STOVES fixed on the FLOOR of a
room?
A.  In order that the air on the lowoer
part of the o'0oom  may be heated by the
fire.
Q.  Wou/ld not the air of the lower part of a
room be heated equally well, if the stoves were fixed
higher up?
A.  No; the heat of a fire has a very
little effect upon the air belowo the level of
the grate;  and, therefore, every grate
shculd be as ntear to the Jloor as possible.
Q.  Or FEET are very frequently COLD when
we sit close by a good fire. Explain the reason of
this.




COMBUSTION.             57
A. As the fire consumes the air
which passes over it, cold air rushes
through the crevices of the doors and
windows alone the bottom  of the room
to supply the deficiency; and these cur
rents of cold air, rushing constantly over
ourfeet, deprive them of their warmth.
Q.  If a piece of PAPER be laid FLAT On a clear
fire, it will NOT BLAZE but CHAR. Why so?
A. Because the carbon of a clear fire,
being sufficiently hot to unite with the
oxygen of the air, produces carbonic acid
gas, which soon envelops the paper laid
flat upon the cinders: but carbonic acid
gas will not blaze.
Q.  If yoM nBLOW the paper, it will BLAZE immediately.  WIhy so?
A.  Because by blowing or opening a
door suddenly, the carbonic acid is dissipated, and the paper fanned into flame.
Q.  ThIrly does WATER EXTINGUIShI  FIRE?
A.  1st-Because the water forms a
coating over the fuel, which keeps it from
the air; and
2dly-The conversion of water znto
steam, draws off the heat of the burning
fuel.
Q.  A LITTLE WATER makes a fire FIERCEIS
while a LARGER quantity of water puts it ouT.
Explain how this is.
3*




58          CHEMICAL ACTION.
A.  Water is composed of oxygcen and
hydrogen; when, therefore, the fire can
decompose the water into its simrple ele.
ments, it serves forfuel to the flame.
Q.  1towt can WATER serve for FUEL to fire?
A.  Because the hydrogen of the water
burns with aficrame; and the oxygren of the
water increases the  intensity  of that
flame.
Q.  Tlthen a house is on fire, zs too LITTLE water
worse than NONE?
A.. Certainly. Unless water be supplied so plentifully as to quelch the fire,
it will increase its intensity, like fuel.
Q.  MWVen will water EXTINGUISH FIRE?
A.  When the supply is so rapid and
abundant that the fire cannot decompose
it.
Q.  Does not a very LITTLE water SLACKEN the
heat of fire?
A.  Yes, till it is decomposed; it then
increases the intensity of fire, and acts
like fuel.
Q.  IVhy does the WICK of a candle (when the
flame has been blown out) very readily CATCH FIRE?
A. Because the wick is already hot,
and a very little extra heat will throw it
into flame.
Q.   Why does the EXTRA heat revive the flamd I




COMBUSTION.              59
A.  Because it again  liberates the
hydrogen of the tallow, and ignites it.
Q.  Cann7ot WOOD be made to BLAZE withOut
actual contact with fire?
A. Yes; if a piece of wood be held
near the fire for a little time, it will blaze,
even thoughli it does not touch the fire.
Q.  TWhy will WOOD BLAZE, even if it does not
touch the fire?
A. Because the heat of the fire
drives out the hydrogen gas of the wood;
which gas is inflamed by contact with
the red hot coals.
Q.  W7hy will a NEIGHBOR'S HOUSE sometimes
CATCH FIRE: though no flame of the burning house
ever touches it?
A. Because the heat of the burning
house sets at liberty the hydrogen gas of
the neighboring wood-work; and this
gas is ignited by the flames or red hot
bricks of the house or fire.
Q.  TWhat is COKE?
A. Coal freed from its volatile gases
by the action of artificial heat.
Q.  Why do STOVES sometimes SMELL very
strongly of SULPHUR?
A. Because coal and coke contain
sulphur; and whenever the draught is
not rapid enough to drive the sulphur Lup
the flue, it is emitted into the roonm.




60         CHEMICAL ACTION.
Q.  What is meant by SPONTANEOUS COMBUS
TION?
A.  Combustion produced without the
application of flame.
Q.  Give an example of spontaneous combustion.
A. Cuals stowed in the hold of a
vessel, and goods packed in a warehouse,
will often catch fire of themselves-especially such goods as cotton, flax, hemp,
rags, &c.
Q.  Why do such GooDS sometimes CATCH FIRE
of themselves?
A. Because they are piled together
in very large masses in a damp state or
place.
Q.  Why does this produce spontaneous combus.
tion?
A. The damp produces decay, or the
decomposition of the goods; and the
great heat of the piled-up mass makes
the decaying goods ferment.
Q. How does this FERMENTATION produce COMBUSTION?
A. During fermentation, carbonic acid
gas is given off by the goods-a slow
combustion ensues-till at length the
whole pile bursts into flame.
Q.  Why is the HEAT of a LARGE MASS ofgood,
GREATER than that of a smaller quantity?
A. Because the carbonic acid cannot




COMBUSTION.              61
escape through the massive pile; ana
the products of decomposition being confined, hasten further changes.
Q.  Why do HAY-STACKS sometimes CATCH FIRE
of themselves?
A. Either because the hay was got
up damp; or else because rain has penetrated the stack.
Q.  Why will a HAY-STACK CATCH FIRE if the
hay be damp?
A.  Because damp hay soon decays,
and undergoes a state of fermentation;
during which, carbonic acid gas is given
off, and the stack catchesfire.
Q.  Roasted COFFEE sometimes CATCHES fire
spontaneously. Explain the reason of this.
A.  The heat of coffee is greatly increased by being roasted; and the carbon of the coffee, uniting with the oxygen
of the air, produces carbonic acid gas, and
bursts into fame.
Q.  Why do old RAGS, used for CLEANING
LAMPS and CANDLESTICKS, sometimes set a HOUSE On
fire?
A. Because they very readily ferment, and (during fermentation) throw
off exceedingly inflammable gases.
N. B. Lamp-black mixed with linseed oil is more liable
to spontaneous combustion than anything that servants
handle.




62         CHEMICAL ACTION.
CHAPTER V.
SMOKE.
Q.  Why does SMOKE ASCEND the chimney?
A. Because the air of the room (when
it passes over the fire) becomes lighter
for being heated; and (being thus made
lighter) ascends the chimney, carrying
the smoke with it.
Q.  What is SMOKE?
A. Small particles of carbon, separated by combustion from the fuel, but not
consunmed.
Q.  Why do SMOKE and steam CURL as they
ascend?
A. Because they are pushed round
and round by the ascending and deScending currents of air.
Q.  Wtlhy does a CLOSE STOVE DRAW Up more
fiercely than an OPEN GRATE?
A. Because the air which supplies
the stove must pass through the fire,
and, as it becomes exceedingly heated,
rushes up the flue with great violence.
Q.  What produces the ROARING noise made by
the fire in a close stove?
A. Air rushing rapidly through the
crevices of the iron door, and up the
chimney flue.




SMOKE.               63
Q.  Whny Is the ROAR LESS if the stove DOOR be
thrown O PEN?
A. Because fresh air gets access to
the fire more easily; and, as the air is
not so intensely heated, its motion is not
so violent.
Q.  Why do some CHIMNEYS SMOKE?
A. Because fresh air is not admitted
into a room so fast as it is consumed by
thefire; in consequence of which, a current of air rushes dowvn the chimney to
supply the deficiency, driving the smoke
along with it.
Q.  Explain this by an illustration.
A. If water be taken with a pail out
of a river, other water will rush toward
the hole as soon as the pail is lifted out;
and, if air be taken from a room (as it
is, when some of it goes up the chimney),
other air will rush toward the void to
fill it up.
Q.  What prevents air being supplied so fast as
it is consumed by thefire?
A. Leather and curtains round the
doors: sand-bags at the threshold and
on the window-frames; and other contrivances to keep out the draught.
Q   TI%!y /uill the air come down the CHIMNEY 
A. Because it can get into the room




64         CHEMICAL ACTION.
n no other way, if the doors and wi-.
dows are all made air-tight.
Q.  What is the best REMEDY in such a:ase?
A. The speediest remedy is to open
the door or window: but by far the best
remedy is to carry a small tube from the
hearth into the external air.
Q.  Why is that the BEST remedy?
A. Because the fire will be plentifully supplied with air by the tube: the
doors and windows may all remain airtight; and we may enjoy a warm fireside, without the inconvenience of
draughts and cold feet.
Q.  W/hy is a CHIMNEY raised so high above
the ROOF?
A.  That it may not smoke; as all
funnels do which are too short.
Q.  What is meant by the FUNNEL Or FLUE Of
a chimney?
A. That part of a chimney through
which the smoke passes.
Q.'Why does a CHIMNEY SMOKE, if the funnel
be very short?
A.  Because the draught of a short
flue is too slack to carry the smoke up
the chimney.
Q.  Why is the DRAUGHT of a SHOrT FLUE
more SLACK than that of a long one?




SMOKE.                65
A.  1st —Because the fire is alrvays
dull and sluggish, if the chimney be too
short:
2dly —Because the smoke rolls out of
the chimney, before it has acquired its
full velocity; and
3dly-Because the wind, rain, and air,
have more influence over a short funnel,
than over a long one.
Q.  ~Why is the FIRE always DULL and SLUG
GISH, if the CHIMNEY-FLUE be very SHORT?
A.  Because the draught is bad; and,
as the rarefied air passes very tardily up
the chimney-fresh air flows as tardily
toward the fire, to supply it with oxygen.
Q.  On what does the INTENSITY offire depend?
A. The intensity of fire is always in
proportion to the quantity of oxygen with
which it is supplied.
Q.  Why does not SMOKE acquire its full VELOCITY in a SHORT funnel?
A.  Because the higher smoke  ascends, (provided the flue be clear and
hot,) the faster it goes: if, therefore, a
funnel be very short, the smoke never
acquires its full velocity.
Q.  Does the DRAUGHT of a chimney depend on
the SPEED of the SMOKE through the.flue?
A. Yes. The more quickly hot air
flies up the chimney, the more quickly




66         CHEMICAL ACTION.
cold air will rush toward the fire to supply
the place; and, therefore, the longer the
flue, the greater the draught.
Q.  lWrhy are the CHIMNEYS of MANUFACTORIES
made so very LONG?
A. To increase the intensity of the
fire.
Q.  ]Wrhy is the INTENSITY of afire increased by
LENGTHENING the FLUE?
A.  Because the draught being greater, more fuel is consumed in the same
time; and, of course, the intensity of the
heat is proportionally greater.
Q.  If a SHORT CHIMNEY cannot be lengthened,
what is the best REMEDY to prevent smoking?
A.  To contract the opening  of the
chimney contiguous to the stove.
Q.  Why will a SMALLER OPENING against the
stove PREVENT the chimney's SMOKING?
A. Because the air will be compelled
to pass nearer the fire; and (being more
heated) will rise through the chimney
more rapidly. This increase of heat will
therefore compensate for the shortness
of the flue.
Q.  Why will a ROOM SMOKE if there be TWO
FIRES tn it?
A. Because the fiercer fire will exhaust the most air, and draw from the
smaller one, to supply its demand.




SMOKE.               67
Q.  Why will a chimneys SMOKE if there be a
t'IRE in TWO ROOMS communicating with each other!
A. Because (whenever the door between the two rooms is opened) air will
rush from the chimney of the inferior
fire to supply the other; and both rooms
will be filled with smoke.
Q.  What is the best REMEDY in thZs case?
A. Let a tube be carried from the
hearth of each stove into the external
air; and then each fire will be so well
supplied, that neither will need to borrow from the other.
Q.  WThy does a HOUSE in a VALLEY or by the
side of higher buildings very often SMOKE?
A. Because the wind (striking
agtainst the surrounding hills or buildings)
bounds back again upon the chimney, and
destroys its draught.
Q.  What is the REMEDY in these cases?
A.  To fix a cowl on the chimney-top,
to turn like a weather-cock, and present
its back to the wind.
Q.  Why will not a COWL always PREVENT a
chimney SMOKING?
A.  Because if the wind be strong, it
will keep the opening of the cowl toward
the higher building or hill; and then the
reflected wind will blow into the cowl,
and down the chimney.




68         CHEMICAL ACTION.
Q.  As a cowl is such a poor remedy, can any
OTHER b& suggested?
A. Yes. If the chimney-flue can be
carried higher than the other buildings
or hills, no wind can enter the flue.
Q.  If a chimney-flue be carried up HIGHER tkan
the buildings or hill, why cannot the wind enler it?
A. Because the reflected wind would
strike against the sides of the chimneyflue, and not pass over the ojpening at all.
Q.  In what OTHER cases will a CHIMNEY SMOKE?
A.  If the door and stove are both
placed on the same side of a room, the
chimney will often smoke.
Q.  Why will a CHIMNEY SMOKE> if the DOOR
and STOVE are both on the SAME SIDE?
A. Because (whenever the door is
opened) a current of air will blow obliquely into the chimney-place, and drive
the smoke into the room.
Q.  What REMEDY can be applied to this evil?
A.  The door must be set opposite to
the chimney-place, or nearly so; and
then the draught from the door will blow
the smoke up the chimney, and not into
fie roorn.
Q.  Why will a CHIMNEY SMOKE if it NEEDS
SWEEPING?
A. Because loose soot obstructs the




SMOKE.               69
free passage of the smoke, delays its
current, and prevents the draught.
Q.  Why will a CHIMNEY SMOKE if it be OUT
OF REPAIR? 
A.  1st-Because the loose mortar and
bricks obstruct the smoke; and
2dly —Cold air (oozing through the
chinks) chills the air in the chimney, and
prevents its ascent.
Q.  Why will a STOVE SMOKE, if the joints of
theflue do not fit air-tight?
A.  Because cold air (oozing through
the joints) chills the air in the flue, and
prevents its ascent.
Q.  Why does an old-fashioned FARM CHIMNEYPLACE generally smoke?
A.  Because the opening is so very
large, that much of the air which goes
up the chimney, has never passed near
the fire; and this cold air (mixing with
the hot) so reduces its temperature that it
ascends very slowly, and the draught is
destroyed.
Q.  W;y does a chimney smoke if the DRAUGHT
be SLACK?
A. Because the current of air up the
chimney is not powerful enough to buoy
up the smoke through the flue.
Q.  If the opening of a chimney be TOO LARGrE
whal REMEDY can be applied?




ro         CHEMICAL ACTION.
A. The chimney-place must be contracted.
Q.  Why will CONTRACTING the chimney-place
PREVENT its SMOKING?
A. Because the air will then pass
nearer the fire; and (being more heated)
fly faster up the chimney.
Q.  Why do almost all CHIMNEYS SMOKE in
GUSTY weather?
A.  Because the column of smoke is
suddenly chilled by the wind, and (being unable to ascend) rushes back into
the room.
Q.  What is the use of a CHIMNEY-POT 2
A. It serves to increase the draught,
when the opening of a chimney is too
large.
Q. How does a CHIMNEY-POT INCREASE tho
DRAUGHT of a chimney?
A. As the same quantity of hot air
has to escape through a smaller opening,
it must pass through more quickly.
Q. Why do BLOWERS help to get a fire up?
A. Because they compel the air to
Wo through the fire, and not over it;
in consequence of which, the fire is well
supplied with oxygen, and the draught
greatly increased.
Q.  Wthy does a BLOWER  INCREASE thM
DRAUGHT?




SMOKE.                 71
A.  Because  the  air  (by  passing
through the fire) is made much hotter,
and ascends the chimney more rapidly.
Q.  /Why is a fire better supplied with oxygen
while the blower hangs before it?
A. Because the blower increases the
draught; and the faster the hot air flies
up the chimney, the faster will cold air
rush toward the fire, to supply it with
oxygen.
Q.  Wty does a parlor often SMELL disagreeably
of SOOT iA SUMMER-TIME.?
A. Because the air in the chimnney
(being colder than the air in the parlor)
descends into the roonm, and leaves a disagreeable smell of soot behind.
Q.  Why are the CEILINGS of PUBLIC OFFICES
generally BLACIK and filthy?
A. Because the heated air of the
office buoys up the dust and fine soot;
which (being unable to escape through
the plaster) is deposited on the ceiling.
Q.  Why are SOMlE parts of the ceiling, BLACKER
and mnore fillhy than others?
A. Because the air, being unable to
penetrate the thick joists of the ceiling
passes by those parts, and deposits its sco:
and dust on others more penetrable.
N. B. The site of this deposit of soot and dust is try
quently determined by draughts and currents of air.




CHEMICAL ACTION.
Q.  What is CHARCOAL?
A.  Wood which has been exposed to
a red heat, till it has been deprived of
all its gases and volatile parts.
Q.  WfJ5 Is a CHARCOAL FIRE hotter than a
woood fire?
A. Because charcoal is very pure
carbon; and, as it is the carbon of fuel
which produces the glowing heat of
combustion, therefore, the purer the carbon, the more intense will the heat of
the fire be.
Q.  Why does charcoal REMOVE the TAINT of
meat?
A.  Because it absorbs all putrescent
effluvia, whether they arise from animal
or vegetable matter.
Q.  Wh/y is WATER PURIFIED by being filtered
through charcoal?
A. Because charcoal absorbs the impurities of the water, and removes all
disagreeable tastes and smells, whether
they arise from animal or vegetable
matter.
Q.  Why are water and wine CASKS CHARRED
inside?
A. Because charring the inside of
a cask reduces it to a kind of charcoal;
and charcoal (by absorbing animal and




SMOKE.                73
vegetable impurities) keeps the l.iquor
sweet and good.
Q.  Why does a piece of BURNT BREAD make
impure WATER fit to drink?
A.  Because the surface of the bread
(which has been reduced to charcoal by
being burnt) absorbs the impurities of the
water, and makes it palatable.
Q.  Why should TOAST and WATER: placed by
the side of the sick, be made of BURNT BREAD?
A. Because the charcoal surface of
burnt bread prevents the water from
being affected by the impurities of the
sick room.
Q.  Why should sick persons eat DRY TOAST
rather than bread and butter?
A. Because the charcoal surface of
the dry toast helps to absorb the acids
and impurities of a sick stomach.
There are other reasons which belong to the science of
medicine.
Q.  W7Zy are TIMBERS which are to be exposed
to damp CHARRED?
A. Because charcoal undergoes no
change by exposure to air and water; in
consequence of which, timber will resist
weather much lonrer after it has been
charreO.
4




74          CHEMICAL ACTION.
CHAPTER VI.
LAMPS AND CANDLES.
Q.  Of what are OIL, TALLOW, and WAX comr
posed?
A.  Principally of carbon and hydrogen gas. The solid part is carbon, the
volatile part is hydrogen gas.
Q.  What is CARBON?
A. A solid substance, generally of a
black color; well known under the
forms of charcoal, lamp-black, coke, &c.
Q.  What is HYDROGEN GAS?
A.  The principal ingredient of water.
It burns so readily that it used to be
called " inflammable air."+
Common coal gas is a mixture of carbon and hydrogen,
called " carburetted hydrogen." See p. 262.
Q.  A CANDLE BURNS when lighted. Explain
how this is.
A. The heat of the lighted wick decomposes the tallow  into its elementary
parts of carbon and hydrogen; and the
hydrogen of the tallow, combining with
the oxygen of the air, produces flame.
Q.  WHERE is the tallow or wax of a candle
decomposed?
A.  In the wick.  The melted tallow
* To make hydrogen gas, see p. 41.




LAMPS AND CANDLES.             75
or wax, rises up the wick by  capillary
attraction, and is rapidly decomposed by
the heat of the flame.
Q.  What is capillary attraction?
A. The power which very minute
tubes possess of causing a liquid to rise
in them above its level.
"Capillary," from the Latin word "capillaris " (like a
hair); the tubes referred to are almost as fine and delicate
as a hair.
Water ascends through a lump of sugar, or piece of
sponge, by capillary attraction. N. B.-The smaller a
tube, the higher will a liquid be attracted by it.
Q.   Why is the FLAME of a candle HOT?
A.  Because the flame liberates latent
heat from the air and tallow.
Q.  How is LATENT HEAT liberated by theflame
of a CANDLE 2
A.  When the elements of the tallow
combine with the oxygen of the air, latent
heat is liberated by the chemical changes.
Q.'Why does the flame of a CANDLE produce
LIGHT?
A.  Because  the  chemical changes
made by combustion excite undulations
of ether, which (striking the eye) produce
light.
See p. 51.
Q.  Tnhy is the fame of a CANDLE YELLOW?
A. It is not so altogether; only the
outer coat of the flame is yellow —the




76         CHEMICAL ACTION.
lower part is violet; and the inside of the
flame hollow.
Q. Why is the outside of the flame YELLOW.
A. Because the carbon of the tallow
(being in a state of perfect combustion)
is made white hot.
See p. 50.
Q.  Why is the BOTTOM part of the flame purple?
A. Because it is overladen with hydrogen, raised from the tallow by the burning wick; and this gas (which burns
with a blue flame) gives the dark tinge
to the bottom of the candle-flame.
Q.  Why is the INSIDE of the flame HOLLOW?
A.  Because it is filled with vapor,
raised from the candle by the heat of the
wick, and not yet reduced to a state of
combustion.
Q.  Describe the different parts of the FLAME of
a common CANDLE.
A. The flame consists of three cones.
The innermost cone is hollow; the intermediate one of a dingy purple hue; and
the outside cone is yellow.
Q.  Why is the intermediate cone of a flame
PURPLE as well as the BOTTOM of the flame?
A. Because the gases are not in a
state of perfect combustion; but contain




LAMPS AND CANDLES.           77
an excess of hydrogen, which gives the
flame a purple tinge.
Q.  WMhy is not the MIDDLE cone in a state of
perfect combustion as well as the outer one?
A. Because the outer cone prevents
the oxygen of the air from getting to the
middle of the flame; and without the
free access of oxygen gas, there is no
such thing as complete combustion.
Q.  Why does the FLAME of a candle point uPWARDS 2
A. Because it heats the surrounding
air, which (being hot) rapidly ascends,
driving the flame upwards at the same
time.
Q.  Why is the FLAME of a candle POINTED at
the top like a cone?
A.  Because the upper part of a flame
is more volatile than the lower; and, as
it affords less resistance to the air, is reduced to a mere point.
Q. W4hy are the LOWER parts of a flame less.
VOLATILE than the upper?
A. Because they are laden with unconsumed gas and watery vapor, whichl
present considerable resistance to the air.
Q.  Why is the FLAME of a candle BLOWN OUIT
by a puff of breath?
A. Because it is severed from that
wick, and goes out for want of support,




78          CHEMICAL ACTION.
Q.   Why does the FLAME of a candle make a
GLASS (which is held over it) DAMP?
A.  Because  a  "watery  vapor" is
made by the combination of the hydrogen
of the tallow with the oxygen of the air;
and this "vapor' is condensed  by the
cold glass held above the flame.
Q.   Why does our hand, held ABOVE a candle,
suffer more from heat than when it is placed BELOW
the flarne, or on ONE SIDE of it?
A. Because the hot gases and air
(in their ascent) come in contact with the
hand placed above the flame; but when
the hand is placed below the flame, or on
one side, it only feels heat from radiation.
Radiation: i. e., emission of rays. The candle-flame
throws out rays of light and heat in all directions; but
when the hand is held above the flame, it not only feels the
heat of the rays~, but also of the ascending current of hot
air, &c.
Q.   Wt1hy is a RUSH LIGHT extinguished more
quickly than a cotton-wick candle?
A. Because a hard rush imbibes the
melted fat or wax much more slowly
than porous cotton; as it imbibes less
fat, it supplies a smaller volume of combustible gases; and, of course, the light
is more easily extinguished.
Q.   Why is it more diffcult to blow out a COTTroN wick than a rush light?
A. Because porous cotton imbibes




LAMPS AND CANDLES.          79
the melted fat, or wax, much more quick.
ly than hard rush; as it imbibes more
fat, it supplies the flame with a larger
volume of combustible gases; and, of
course, the light is with more difficulty
extinguished.
Q.  Why is a GAS FLAME more easily extinguished when the jet is very slightly turned on, than
when it is in full stream?
A. Because there is less volume of
combustible gases in the small flame
than in the full blaze.
Q.  Why does an EXTINGUISHER put a candle
out?
A.  Because the  air in  the  extinguisher is soon exhausted of its oxygen by
the flame: and when there is no oxygen, flame goes out.
Q.  Why does not a candle set fire to a PIECE
of PAPER twisted into an extinguisher, and used as
such?
A. 1st-Because the flame very soon
exhausts the oxygen contained in the paper extinguisher: and
2dly — The flame invests the inside
of the paper extinguisher with carbonic
acid gas, which prevents it from blazing.
Q.  Why is a LONG WICK never upright?
A. Because it is bent by its own
weight.




80         CHEMICAL ACTION.
Q.  A LONG WICK is covered with an EFFLORESVENCE at the top.  What does this arisefrom?
A. The knotty or flowery appearance of the top of a wick arises from an
accumulation of particles partly selparated but still loosely hanging to the wick.
Q.  Why is not the END of a long wick BURNT
OFF as it hangs over the flame?
A. Because the length of the wick
diminishes the heat of the flame; so that
it is no longer hot enough to consume the
wick.
Q.  Why do PALMER'S METALLIC WICKS never
need SNUFFING?
A. Because the wick is divided into
two parts, each of which bends toward
the outside of the flame, where the end
is intensely heated, and separated from the
wick by the current of air up the candle.
N. B. The small wire twisted in the wick greatly assists
the process.
Q.  Why do common CANDLES require to be
SNUFFED?
A. Because the heat of the flame is
not sufficient to consume the 7wick; and
the longer the wick grows, the less heat
the flame produces.
Q. Why do WAX CANDLES NEVER need SNUFFING?
A. Because the wick of rwax candles




LAMPS AND CANDLES.         81
is made of very fine thread, which the
heat of the flame is sufficient to consume.
The wick of tallow candles (on the other
hand) is made of coarse cotton, which is
too substantial to be consumed by the
heat of the flame, and must be cut off
by snuffers.
Q.  Why does a PIN stuck in a RUSH LIGHT
EXTINGUISH it?
A. Because a pin (being a good
conductor) carries away the heat of the
flame from  the wick, and prevents the
combustion of the tallow.
Q.  What is the SMOKE of a CANDLE 2
A. Solid particles of carbon, separated from the wick and tallow, but not
consumed.
Q.  Why are SOME particles consumed and not
OTHERS?
A. The combustion of the carbon depends upon its combining with the oxygen
of the air: now, as the outer surface of
the flame prevents the access of air to the
interior parts, much of the carbon of
those parts passes off in smoke.
Q.  Wh.y do LAMPS SMOKE?
A. Either because the wick is cut
unevenly, ot else because it is turned up
too high.
4*




'20       CHEMICAL ACTION.
Q.  Why does a LAMP SMOKE when the 1ICK ii
ct UNEVENLY?
A.  1st-Because the points of the
jagged edge (being very easily separated
from the wick) load the flame with more
carbon than it can consume; and
2dly —As the heat of the flame is
greatly diminished by these bits of wick,
it is unable to consume even the usual
quantity of smoke.
Q.  Why does a LAMP SMOKE when the WICK iS
turned up too HIGH?
A. Because more carbon is separated
from the wick than can be consumed by
theflame.
Q.  Why do not " ARGAND BURNERS' smoke?
A. Because a current of air passes
through the middle of the flame; in consequence of which, the carbon of the
interior is consumed, as well as that in
the outer coating of the flame.
Q.  yWhy does a LAMP-GLASS DIMINISH t1h
SMOKE of a lamp?
A. 1st-Because it increases the
supply of oxygen to the flame, by producing a draught; and
2dly-It concentrates and reflects the
heat of the flame; in consequence of
which, the combustion of the carbon is




ANIMAL HEAT.            83
more perfect, and very little escapes
unconsuined.
CHAPTER VII.
ANIMAL HEAT.
Q.  Wh7at is the cause of ANIMAL HEAT?
A. Animal heat is produced by the
combustion of hydrogen and carbon in
the capillary vessels.
Q.  What are CAPILLARY VESSELS?
A. Vessels as small as hairs running
all over the body; they are called capillary from  the Latin word "capilla'ris"
(like a hair).
Q.  Do these CAPILLARY VESSELS run all over
the human body?
A. Yes. Whenever blood flows from
a wound, some vein or vessel must be
divided; and as you can bring blood
from any part of the body by a very
slight wound, these little vessels must
run through every part of the human
frame.
Q. How do HYDROGEN gas and CARBON get
tnto these very little vessels?
A The food we eat is converted into




84         CHEMICAL ACTION.
blood; and blood contains both hydrogen
and carbon.
Q. Hiow does COMBUSTION take place in the ce
pillary vessels?
A.  The carbon of the blood combines
with oxygen of the air we breathe, and
forms into carbonic acid gas.
Q.;tWhat BECOMES of this CARBONIC ACID GAS
formed in the human blood?
A. The lungs throw off almost all of
it into the air, by the act of respiration.
Q.  What GAS is generated in a common FIRE
by COMBUSTION?
A.  Carbonic acid gas-formed by the
union of the carbon of fuel with the oxygen of the air.
Q.  What GAS is generated by a lighted CANDLE
or LAMP?
A.  Carbonic acid  gas —formed  by
the union of the carbon of the oil or tallow with the oxygen of the air.
Q.  What is the cause of SPONTANEOUS COMBUSTION?2
A.  The piled-up goods fermnent from
heat and danmp; and (during fermentation) carbonic acid gas isformed, which is
attended with combustion.
Q.  Does the HEAT of the HUMAN BODY arise from
the SAIE CAUSE as the heat of FIRE?
&. Yes, precisely. The carbon of




ANIMAL HEAT.              85
the blood combines with the oxygen of the
air inhaled, and produces carbonic acid
gas, which is attended with combustion.
Q.  If animal heat is produced by COMBUSTION,
why does not the human body BURN UP like a coal or
candle?
A. It actually does so. Every muscle, nerve, and organ of the body, actually wastes away like a burning candle;
and (being reduced to air and ashes) is
rejected from the system as useless.
Q.  If every bone, muscle, nerve, and organ, is
thus consumed by combustion, why is not the BODY
entirely CONSUMED?
A. It would be so, unless the parts
destroyed were perpetually renewed: but
as a lamp will not go out, so long as it
is supplied with fresh oil-neither will
the body be consumed, so long as it is
supplied with sufficient food.
Q.  WThat is the principal DIFFERENCE between
the combustion of a FIRE or LAMP and that of the
HUMAN BODY?
A. In the human body, the combustion is effected at a much lower temperature; and is carried on more slowly,
than it is in a lamp or fire.
Q.  How is it that carbon can be made to burn
at so LOW a temperature in the human body?
A. Because the carbon in the blood




86         CHEMICAL ACTION.
is reduced to very minute particles; and
these particles are ready to undergo a
rapid change as soon as oxygen is
supplied.
Q.  When a man is STARVED,what parts of the
body go first?
A.  First the fat, because it is the
most combustible; then the muscles;
last of all the brain; and then the man
dies, like a candle which is burnt out.
Q.  Why does WANT of sufficient NOURISHMENT
often produce MADNESS 2
A.  Because after thefat and muscles
of the body have been consumed by animal combustion, the brain is next attacked; and (unless the patient dies) madness ensues.
Q.  Why does a man SHRINK when STAnVED?
A. Because the capillary fires feed
upon the human body when they are not
supplied with food-fuel. A starved man
shrinks just as a fire does, when it is not
supplied with fuel.
Q.  What is the FUEL of the BODY?
A.  Food  is the fuel of the body.
The carbon of the food mixing with the
oxygen of the air, evolves heat in the
same way that a fire or candle does.
Q.  Why is EVERY part of the BODY WARM?




ANIMAL HEAT.            87
A. Because the capillary vessels run
through every part of the human body,
and the combustion of blood takes place
in the capillary vessels.
See p. 84.
Q. Why does RUNNING make us WARnI?
A. Because we inhale air more rapidly when we run, and cause the blood
to pass more rapidly through the lungs
in contact with it. Running acts upon
the capillary vessels as a pair of bellows
on a commonfJire.
Q.  Why does INHALING AIR RAPIDLY make the
body feel WARmA 
A.. Because more oxygen is introduced into the body. In consequence
of which, the combustion of the blood is
more rapid —the blood itself more heated
-and every part of the body is made
warmer.
Q.'Why does HARD WORK produce HUNGER?
A. Because it produces quicker respiration; by which means, a larger amount
of oxygen is introduced into the lungs,
and the capillary combustion increased.
Hunger is the notice (given by our body)
to remind us that our food-fuel must be
replenished.
Q. IVhy does SINGING make us HUNGRY?




88        CHEMICAL ACTION.
A. Because it increases respiratimo;
and, as more oxygen is introduced into
the lungs, our food-fuel is more rapidly
consumed.
Q.  Why does READING ALOUD make us feel
HUNGRY?
A. Because it increases respiration;
and, as more oxygen is introduced into
the lungs, our food-fuel is more rapidly
consumed.
Q.  Why do we feel less HUNGRY in the nmght
than in the DAY?
A.  Because we breathe more slowly
during sleep; therefore, less oxygen is
introduced into the lungs, to consume our
food-fuel.
Q.  1'Vhy do we need WARMER CLOTHING by
NIGHT than by DAY?
A. 1st-Because the night is generally colder than the day; and
2dly —Our bodies are colder also; because we breathe more slowly, and our
animal combustion is retarded.
Q.  Why do we PERSPIRE whean very hot?
A. The pores of the body are like the
safety valves of a steam-engine,' when
the heat of the body is very great, some
of the combustible matter of the blood
is thrown off in perspiration; and the
heat of the body kept more temperate.




ANIMAL HEAT.              89
Q.  Tiv7y do persons feel LAZY and averse to
exercise when they are HALF-STARVED or ILL-FED?
A. Animalfood contains great nou
rishment, and produces a desire for active
occupations; but, when the body is not
supplied with strong food, this desire
for muscular action ceases, and the person
grows slothful.
Q.  Why have persons who follow HARD, OUTOF-DOORS OCCUPATIONS more APPETITE than those
who are engaged in SEDENTARY pursuits?
A. Hard bodily labor in the open air
causes nuch oxygen to be conveyed into
the lungs by inspiration; the combustion
of the food is carried on quickly; anima,
heat increased; and need for nutritious
food more quickly indicated by craving
hunger.
Q.  Why have persons who follow SEDENTARY
PURSUITS less APPETITE than ploughmen and masons?
A.  1st-Because the air they inhale
is less pure, being deprived of some of
its oxygen: and
A.  2dly-Their respiration is neither
so quick, nor so strong; and, therefore,
the combustion of their food is carried 9n
more slowly.
Q.  Whey do we like strong MEAT and GREASY
food when the WEATHER is very COLD?
A.  Because strong meat and grease




90         CHEMICAL ACTION.
contain large portions of carbon and hy.
drogen; which (when burned in the
blood) produce a larger amount of heat,
than any other kind of food.
Q.  W4rhy do persons EAT MORE food in COLD
weather than in hot?
A. Because the body requires more
fuel in cold weather, to keep up the same
amount of animal heat; and as we put
more coals on a fire on a cold day, to keep
our roomn  warm; so we eat more food
on a cold day, to keep our body warm.
Q.  XWhy does COLD produce RIUNGER?
A. 1st - Because the air contains
more oxygen in cold weather; and, therefore, fires burn more fiercely, and animal
combustion is more rapid: and
2dly-As we are more active in cold
weather, our increased respiration acts
like a pair of bellozws on the capillary
combustion.
Q.  Why does rapid DIGESTION produce a cra.
Ving APPETITE?
A. This is a wise providence to keep
our bodies in health; they give notice (by
hunger) that the capillary fires need replenishinrg, in order that the body itselj
may not be consumed.
Q.  W-hy do we feel a desire for ACTIVITY In
cold weathei?




ANIMAL HEAT.             91
A.  Ist-Because activity increases
the warmth of the body, by fanning the
combustion of the blood: and
2dly-The strong food we eat creates
a desire for muscular exertion.
Q.  W7.y are the Esquimaux so passionately
fond of TRAIN OIL and WHALE BLUBBER?
A. Because oil and blubber contain
large quantities of carbon and hydrogen,
which are exceedingly combustible;
and, as these people live in climates of
intense cold, the heat of their bodies is
increased by the greasy nature of their
food.
Q.  Trhy do we feel a DISLIKE to strong meat
and greasy food in very HOT weather?
A. Because strong meat and grease
contain so much carbon and hydrogen,
that they would make us intensely hot:
we therefore, instinctively refuse them in
hot weather.
Q.  Why do we like FRUITS and VEGETABLES
mest in hot weather?
A. Because they contain less hydrogen and carbon than meat; and, therefore, produce both less blood, and blood
of a less combustible nature.
Q.  Hrhy is the blood of a less COMBUSTIBLE nalure, if we live chiefly upon FRUITS and VEGETABLES?
A. Because friuits and vegetables




92         CHEMICAL ACTION.
supply the blood with a very large
amount of water; which is not combustible, like the carbon and hydrogen  of
strong meat.
Q.  How do FRUITS and VEGETABLES COOL the
BLOOD?
A.  1st-They diminish the amount of
carbon and hydrogen in the blood, which
are the chief causes of animal heat: and
2dly —They supply the blood with a
large amount of water, which exudes
through the skin, and leaves the body
cool.
Q.  Why do we feel LAZY and averse to activity
in very HOT WEATHER? 
A. 1st-Because muscular activity
increases the heat of the body, by quickening the respiration: and
2dly —The food we eat in hot weather (not being greasy) naturally abates
our desire for bodily activity.
Q.  Why do the inhabitants of TROPICAL countries live chiefly upon RICE and FRUIT?
A. Because rice and fruit (by digestion) are mainly converted into water; and
(by cooling, the blood) prevent the tropical
heat from feeling so oppressive.
Q.  Why are the ILL-FED instinctively AVERSB
so CLEANLINESS? 




ANIMAL HEAT.            93
A.  Because cleanliness increases hunger, which they cannot allay by food.
Q.  Why are the ILL-CLAD also instinctively
averse to CLEANLINESS?
A. Because dirt is warm, (thus pigs,
who love warmnth, are fond of dirt); to
those, therefore, who are very ill-clad,
the warmlth of dirt is agreeable.
Q.  Tny are very POOR PEOPLE instinctively
AVERSE to VENTILATION?
A. 1st-Because ventilation increases
the oxygen of the air-the combustion of
food-and the cravings of appetite: and
2dly-Ventilation cools the air of our
rooms: to poor people, therefore, who are
ill-clad, the warmth of an ill-ventilated
apartment is agreeable.
Q.  Why does FLANNEL, ~C., make us WARM?
A. Flannel and warm clothing do
not make us warm, but merely prevent
our body from becoming cold.
Q. Ilow does FLANNELS Cc., prevent our body
from becoming cold?
A. Flannel (being a bad conductor)
will neither carry off the heat of our body
into the cold air, nor suffer the cold of
the air to come in contact with our warm
body: and thus it is, that flannel clothing
keeps us warm.




94       MECHANICAL ACTION.
Q.  Why are FROGS and FISHES COLD BLOODED
animals?
A. Because they consume very little
air; and, without a plentiful supply of
air, combustion is too slow to generate
much animal heat.
Q.  Why is a DEAD BODY COLD?
A.  Because air is no longer conveyed
to the lungs, after respiration has ceased;
and, therefore, animal heat is no longer
generated by combustion.
MECHANICAL ACTION.
CHAPTER VIII.
1.-PERc USSION.
Q.  Now is heat produced by MECHANICAL ACTION?
A.  1.-By Percussion. 2. —By Friction.  And 3.-By Condensation.
Q.  What is meant by PrECUSSION?
A.  The act of striking; as when a
blacksmith strikes a piece of iron on his
anvil with his hammer.
Q.  Why does STRIKING IRON make it RED HOT?
A.  Because it condenses the particles




PERCUSSION.             95
of the metal, and makes the latent heat
sensible.
Q. Does COLD iron contain HEAT?
A. Yes; everything contains heat;
but, when a thing feels cold, its heat is
LATENT.
Q.  What is meant by LATENT HEAT?
A.  Heat notperceptible to ourfeelings.
WVhen anything contains heat without
feeling the hotter for it, that heat is
called " latent heat."
See p. 37.
Q.  Does COLD iron contain latent HEAT 2
A. Yes; and when a blacksmith
compresses the particles of iron by his
hammer, he brings out latent heat; and
this makes the iron red hot.
Q.  How  used blacksmiths to LIGHT THEIR
MATCHES before the general use of lucifers?
A. They used to place a soft iron
nail upon their anvil; strike it two or
three times with a hammer; and the
point became sufficiently hot to light a
brimstone match.
Q.  How can a NAIL (beaten by a hammer)
IGNITE a brimstone MATCH?
A. The particles of the nail being
compressed by the hammer, can no longer
contain so much heat in a latent state, as




96         MECHANICAL ACTION.
they did before; some of it, therefore,
becomes sensible, and increases the temperature of the iron.
Q.   Why does STRIKING a FLINT against a
piece of STEEL produce a SPARK?
A. Because it compresses those parts
of the flint and steel which strike toge
ther. In consequence of which, some of
their latent heat is disturbed, and exhibits itself in a spark.
Q. How does this development of HEAT produca
a SPARK and set TINDER on fire?
A.  A very small fragment (either of
the steel or flint) is knocked off' red hot,
and sets fire to the tinder on which it
falls.
Q.  Why is it needful to keep BLOWING th]
TINDER with the breath?
A. In order that the increased supply of air may furnish the tinder with
more oxygen to assist combustion.
Q.   Where does the OXYGEN of the air COME
FROM, which is b.own to the lighted tinder?
A.  From  the air itself, which is composed of two gases (nitrogen and oxygen)
mixed together.
Every 5 gallons of common air contain nearly 4 gallons
of nitrogen, and 1 of oxygen.
Q.   What is the USE of OXYGEN GAS to lighted
tznder?




FRICTION.             97
A.  It supports the combustion of the
tinder.  Blowing lighted tinder carries
oxygen to it and quickens it, in the same
way as a pair of bellows quickens a dull
fire.
Q.  Why do HORSES sometimes STRIKE FIRE
with, their FEET 
A.  Because when their iron shoes
strike against the flint stones of the road,
very small fragments (either of the shoe
or stones) are knocked off red hot, and
look like sparks.
Q.  What makes these fragments RED HOT?
A. The percussion condenses the part
struck: In consequence of which, some
of its latent heat is rendered sensible, and
exhibits itself in these red hot fragments.
CHAPTER IX.
2.-FRICTION.
Q. What is meant by FRICTION?
A. The act of rubbing two things to.
gether; as the Indians rub two pieces of
wood together to produce fire.
Q.  How do the Indians produce FIRE by merda
RUBBING TWO PIECES of dry WOOD TOGETHER?
5




98        MECHANICAL ACTION.
A. They take a piece of dry wood,
sharpened to a point, which they rub
quickly up and down a flat piece, till a
groove is made; and the dust (collected
in this groove) catches fire.
Q.  Wh7y does the dust of the WOOD CATCH FIRE
by RUBBING?
A. Because latent heat is developed
from the wood byfriction.
The best woods for this purpose are boxwood against
mldberry, or laurel against poplar or ivy.
Q.  Do not CARRIAGE WHEELS sometimes CATCH
FIRE?
A.  Yes; when the wheels are dryor fit too tightly-or revolve very rapidly.
Q.  Why do wheels catch fire in such cases?
A. Because the friction of the wheels
against the axle-tree disturbs their latent
heat, and produces ignition.
Q. What is the use of GREASING CART WHEELS?
A.  Grease lessens the fiiction; and,
because there is less friction, the latent
heat of the wheels is less disturbed.
Q.  MWhy does RUBBING our HANDS and FACES
make them feel WARM?
A.  1st-Because friction excites the
latent heat of our hands and faces, and
makes it sensible to our feeling: and
2dly —The blood is made to circulate
more quickly; in consequence of which,




FRICTION.              99
the quantum of heat (left in its passage)
is increased.
Q.  When a man has been almost DROWNED,
why is suspended animation RESTORED by RUBBING I
A.  ist-Because friction excites the
latent heat of the half-inanimate body:
and
2dly-It makes the  blood  circulate
more quickly, which increases the animal
heat.
Q.  Why do two pieces of ICE (rubbed together)
MELT?
A. Ice contains 140 degrees of latent
heat, and (when two pieces are rubbed
together) some of this latent heat is made
sensible, and melts the ice.
Q.  Are not FORESTS sometimes SET On FIRE by
friction?
A. Yes; when two branches or
trunks of trees (blown about by the
wind) rub violently atgainst each other,
their latent heat is deve, ned, and sets fire
to the forests.
Q.  Why do carpenters' Too:.S (such as gimlets,
saws, files, 4-c.) become HOT when used?
A.  Because the friction of the tools
against the wood disturbs its latent heat,
and makes it sensible.
Q.  Gi Pan ILLUSTRATION of this.
A. W. en cannon is bored, thelborers




100         MECHANICAL ACTION.
becon;e so intensely hot from friction, that
they would blister the hands, if touched.
Q.  1W7y do these BORERS become so intensely
HOT?
A.  Because the friction of the borers
against the metal is so great, that it sets
free a large quantity of latent heat.
CHAPTER X.
3.-CONDENSATION  or COMPRESSION.*
Q.   MThat is meant by COMPRESSION?
A.  The act of bringing parts nearer
together; as a sponge is compressed by being squeezed in the hand.
Q.   Cannot HEAT be evolved from  common air
merely by COMPRESSION?
A. Yes; if a piece of German tinder
be placed at the hottonm of a glass tube,
and the air in t je tube compressed by
a piston, the tin' er will catch fire.
In a common syrire e or squirt, the handle part (which
contains the sucker, and is forced up and down) is called
"the Piston."
* N. B. The reduction of matter into a smaller compass by any external or wmchanical force is called COMPRESSION.
The reduction of matter into a smaller cor pass by some
internal action (as by the escape of caloric' s called cov
DENSATIOII.




CONDENSATION OR COMPREAsION. 101
Q.  MWy will the tinder catch fire?
A.  Because the  air is conpressed,
and its  latent heat being squeezed out,
sets fire to the tinder at the bottom of
the tube.
Q.   When an AIP-GUN is discharged in the
dark, why is it accompanied with a slight F'LASH? 
A. Because the air is very rapidly
condensed, and its latent heat developed
in a fash of light.
N. B. If a glass lens be fixed in the copper ball, (where
the air of the gun is condensed,) a flash of light may be
distinctly discerned at the stroke of the piston.
Q.   Why do DETONATING salt and powder EXPLODE on being rubbed or struck?
A. Because the mechanical action of
rubbing or striking, produces sufficient
heat to ignite the explosive materials of
which they are composed.
Q.   Why are SHOT and CANNON-BALLS HEATED
by being dischargedfrom a gun or cannon?
A.  Because the air is so rapidly condensed, when the discharge is mnade, that
sufficient latent heat is developed to
make the shot or balls hot.
Q.  WVhy does the HOLE made by a shot or can.
non-ball in a wall or timber. look as if it were BURNT?
A. Because the shot or cannon-balls
were so heated by the discharge, as ac.
tually to scorch the material into which
they penetrated.




102        ElFECTS OF HEAT.
EFFECTS OF HEAT.
CHAPTER XI.
1.-EXPANSION.
Q.  What are the principal EFFECTS of H:EAT?
A.  1.-Expansion.   2. - Liquefac.
tion.  3.-Vaporization.  4.-Evaporation; and 5.-Ignition.
Q.  Does HEAT EXPAND AIR?
A. Yes; if a bladder (partially filled
with air) be tied up at the neck, and laid
before the fire, the air will expand till the
bladder bursts.
Q.  Why will the AIR SWELL if the bladder be
laid before the fire?
A. Because the heat of the fire will
drive the particles of air apartfrom each
other, and cause them to occupy more
room than they did before.
Q.  Why do unslit CHESTNUTS CRACK with a
loud noise when ROASTED?
A. Because they contain a great deal
of air which is expanded by the heat of
the fire; and not being able to escape,
bursts violently through the thick rind,
slitting it, and making a great noise.




EXPANSION              103
Q.  What occasions the loud cRACK or report
wohich we hear?
A.  1st-The sudden bursting of the
rind makes a report; in the same way
as a piece of wood or glass would do, if
snapped in two: and
2dly-The escape of hot air from the
chestnut makes a report also; in the
same way as gunpowder, when it escapes
fromn a gun.
Q.  TWhy does the sudden BURSTING of the rind,
or SNAPPING of a piece of wood, make a REPORT? 
A. Because a violent jerk is given
to the air, when the attraction of cohesion is thus suddenly overcome. This
jerk produces rapid undulations in the
air, which (striking upon the ear) give
the brain a sensation of sound.
Q.  WMIy does the ESCAPE of AIR from the chestnut, or the EXPLOSION of GUNPOWDERq produce a
REPORT?2
A. Because the sudden expansion of
the imprisoned air produces a partial
vacuum; the report is caused by the
rushing offresh air to fill up this vacuum.
See Thunder, p. 15.
Q. If a CHESTNUT be SLIT, it will NOT CRACK;
ohy is this?
A. Because the heated air of the




104        EFFECTS OF HEAT.
chestnut can then freely escape through
the slit in the rind.
Q.  Why does an APPLE split and SPURT about
when roasted?
A. Because it contains a vast quantity of air, which (being expanded by the
heat of the fire) bursts through the peel,
carrying the juice of the apple along
with it.
Q.  Does an APPLE contain MORE AIR in proportion than a CHESTNUT?
A. Yes, much more. There is as
much condensed air in a common apple,
as would fill a space 48 times as large
as the apple itself
Q.  How can all this AIR be stowed in an APrLE?
A. The inside of an apple consists of
little cells (like a honey-comb), each of
which contains a portion of the air.
Q.  When an APPLE is ROASTED, why is one
part made SOFT, while all the rest remains hard?
A.  Because the air'in those cells next
the fire is expanded, and flies out; the
cells are broken, and their juices mixed
together; so the apple collapses (from loss
of air and juice), and feels soft in those
parts.
Q.  What is meant by the "apple COLLAPSINq?"
A. It means that the plumpness gives




EXPANSION.             105
way, and the apple becomes flabby and
shrivelled.
Q.  Wflly do SPARKS of fire start (with a crackling noise) from pieces of WOOD laid upon a FIRI?
A. Because the air (expanded by
the heat)forces its way through the pores
of the wood; and carries along with it
the covering of the pore, which resisted
its passage.
Q.  What is meant by the " PORES of the WOOD?"
A. Very small holes in the wood,
through which the sap circulates.
Q.  W'hat are the SPARKS OF FIRE which burst
from the WOOD?
A. Very small pieces of wood made
red hot, and separated from  the log by
tlleforce of the air, when it bursts from
its confinement.
Q.  Wthy does DRY PINE make more snapping
than any OTHER WOOD?
A.  Because the pores of pine are verm
large, and contain more air than wood
of a closer grain.
Q   Why does GREEN WOOD make LESS SNAPPING than DRY?
A. Because the pores being' filled
with sap, contain very little air.
Q.  Why does DRY WOOD mak# MORE SNAPPING
than green?
5.




106        EFFECTS OF HEAT.
A. Because the sap is dried up, and
the pores are filled with air instead.
Q.  Why does DRY wood BURN more easily than
GREEN'or wet wood?
A. Because the pores of dry wood
are filled with air which supports combustion; but the pores of green or wet
wood are filled with moisture, which extinguishes flame.
Q.  Why does MOISTURE EXTINGUISH FLAME?
A. 1st-Because it prevents the hydrogen of the fuel from mixing with the
oxygen of the air, to form carbonic acid
gas; and
2dly-Because  heat is  perpetually
carried off, by the formation of the sap
or moisture into steam.
Q.  Why do STONES SNAP and fly about when
keated in the FIRE?
A. Because the close texture of the
stone prevents the hot air from escaping;
in consequence of which, it bursts forth
with great violence, tearing the stone to
atoms, and forcing the fragments into
the room.
Probably some part of this effect is due to the setting
free of the water of crystallization.
Q.  When bottled ALE or PORTER is set before a
FIRE, why is the CORK FORCED OUT sometimes?
A. Because the carbonic acid of the




EXPANSION.               107
liquor expands by the heat, and drives
out the cork.
Carbonic acid gas is a compound of carbon and oxygen.
The carbon comes from thefuel, and the oxygen from the
air. See p. 40.
Q.   Why does ALE or PORTER FROTH more after
it has been set before the fire?
A. Because the heat of the fire sets
free the carbonic acid of the liquor;
which is entangled as it rises throuoh
the liquor, and produces bubbles or froth.
Q.  ~When a boy makes a BALLOON, and sets
fire to the cotton or sponge (which has been steeped in
spirits of wine), why is the balloon INFLATED?
A.  Because the air of the balloon is
expanded by the flame, till every crumple
is inflated and made smooth.
Q.  hthy does the BALLOON RISE after it has
been inflated by the expanded air?
A. Because the same quantity of air
is expanded to three or four times its original volunze; and made so much lighter,
that even when all the paper, wire, and
cotton are added, it is still lighter than
common air.
Q.  Why does SMOKE RUSH UP a CHIMNEY?
A. Because the heat of the fire expands the air in the chimney; which
(being thus made lighter than the air
around) rises up the chimney, and carries
the smoke in its current.




t08        EFFECTS OF HEAT.
Q.  Why will a LONG chimney qMOKE, unless
the FIRE be pretty FIERCE?
A.  Because the heat of the fire will
not be sufficient to rarefy all the air in
the chimney.
Q.  WHY will the chimney smoke, unless thefire
be FIERCE enough to heat ALL the air in the CHIMNEY
FLUE?
A.  Because the cold air (condensed
in the upper part of the flue) will sink
from its own weight; and sweep the ascending smoke back into the room.
Q.  What is the use of a COWL /upon a chimney-pot?
A. It acts as a screen, to prevent the
wind from blowing into the chimney.
Q.  What HARM would the WIND do if it were
to BLOW into a C111MNEY?
A.  1st-It would prevent the smoke
from getting out; and
2dly-The cold air (introduced into
the chimney by the wind) would fall
down the flue, and drive the smoke with
it into the room.
Q.  Why are some thinps SOLID, others LIQUID,
and others GASEOUS?
A. Because the particles which compose some things are nearer together
than they are in others. Those in which
the particles are closest are solid; those




EXPANSION.            109
in which they are furthest apart are gas.
eous; and the rest liquid.
Q.  TVhy does heat change a SOLID (like ice)
first into a LIQUID, and then into a GAS?
A. Because heat drives the component particles further asunder; hence a
certain quantity of heat chances solid ice
into a liquid-and a further addition of
heat changes the liquid into steam.
Q.  I/ty does WATER SIMMER before it boils?
A. Because the particles of water
near the bottom of the kettle (being formed into steam sooner than the rest) shoot
upwards; bult are condensed again (as
they rise) by the colder water, and produce what is called " simmering."
Q.  What is meant by SIMMERING?
A. A gentle tremor or undulation on
the surface of the water.  When water
simmers, the bubbles collapse beneath the
surface, and the steam is condensed to
water again; but when water boils, the
bubbles rise to the surface, and the steam
is thrown off
Collapse, i. e., burst.
Q.  Why does a KETTLE SING,when the water
rimmers?
A. Because the air (etltangled in the
water) escapes byfits and starts through




110        EFFECTS OF HEAT.
the spout of the kettle, which makes a
noise like a wind instrument.
Q.  tvyly does NOT a kettle SING when the water
BOII.S?
A. Because all the water is boiling
hot; so the steam escapes in a continuous streamt, and not by fits and starts.
Q.  W'hen does a kettle sing MOST?
A. When it is set on the hob to boil.
Q.  W'/hy does a kettle SING MORE when it is sel
on the SIDE of afire, than when it is set in the MIDST
of the fire?
A. Because the heat is applied so
unrequally, that onze side is made hotter
than the other; in consequence of which,
the steam is more entangled.
Q.  Why does a KETTLE sing, when the boiling
water begins to COOL again?
A.  Because the upper surface cools
first; and the steam (which rises from
the lower part of the kettle) is again entangled, and escapes by fits and starts.
Q.  Why does BOILING WATER SWELL?
A.  Because it is expanded by the heat:
x. e.-The heat of the fire drives the par.
tides of water further apart fiom  each
other: and (as they are notpacked so closely together) they take up more room;  in
other words, the water swells.




EXPANSION.               111
Q.'Ihat is meant when it is said, that " HEAT
drives the PARTICLES of water further APAaT from
each other?"
A.  Water is composed of little globules, like very small grains of sand; the
heat drives these particles away from
each other; and (as they then  require
more room) the water siwells.
Q.   Why does BOILING WATER BUBBLE?
A. Because the vapor (risinc through
the water) is entangled, and forces up
bubbles in its effort to escape.
N. B. All the air of water is expelled at the commencement of its boiling.
Q.   Why does a KETTLE sometimes BOIL OVER?
A.  Because the water is expanded by
heat; if, therefore, a kettle is filled wvith
cold water, some of it must run over, as
soon as it is expanded by heat.
Q.  But I have seen a KETTLE BOIL OVER, altho:ogh it has not been filled FULL of WATER; how do
you account for THAT?
A. If a fire be very fierce, the air and
vapor are expelled so rapidly, that the
bubbles are very numerous; and (towerering one above another) reach the top
of the kettle, and fall over.
Q.   Why is a pot (which was full to OVERFLOWING, while the water was boiling HOT) NOT
FULL, after it has been taken of the fire for a short
time?




112         EFFECTS OF HEAT.
A. Because (while the water is boil.
ing) it is expanded by the heat, and fills
the pot even to overflowing: but, when
it becomes cool, it contracts again, and
occupies a much less space.
Q.'Why does the water of a KETTLE run out
of the SPOUT when it BOILS?
A. Because the lid fits so tightly, that
the steam cannot lift it up and escape:
being confined, therefore, in the kettle, it
presses on the tvater with great power,
and forces it out of the spout.
Q.  W'hat causes the RATTLING NOISE, so often
made by the LID of a saucepan or boiler?
A. The steam (seeking to escape)
forces up the lid of the boiler, and the
weight of the lid carries it back again:
this being done frequently, produces a
rattling noise.
Q.  If the steam COULD NOT LIFT UP THE LID
of the boiler how would it escape?
A. If the lid fitted so tilghtly, that the
steam could not raise it up, the boiler
would burst intofragments, and the consequences might be fatal.
Q.  When steam pours out.from the spout of a
kettle, the STREAM begins apparently HALF AN INCH
of the SPOUT why does it not begin CLOSE to ths
spout?
A.  Steam is really invisible ~ and the




EXPANSION.             113
half-inch  (between the spout and the
" stream of mist", is the real steam, before
it has been condensed by air.
Q.  Why is not ALL the steam INVISIBLE as
well as that half-inch?
A. Because the invisible particles are
condensed by the cold air; and, rolling
one into another, look like a thick mist.
Q.  Tlhat BECOMES of the STEAM? for it soon
vanishes.
A. After it has been condensed into
mist, it is dissolved by the air, and dispersed abroad as invisible vapor.
Q. And what BECOMES of the INVISIBLE VAPOR?
A.  Being lighter than air, it ascends to
the upper regions of the atmosphere,
where (beinc acain condensed) it contributes to form clouds.
Q.  Why does a METAL SPOON (left in a saucepan) RETARD the process of BOILING?
A. Because the metal spoon (being
an excellent conductor) carries off the heat
from the water; and (as heat is carried
off by the spoon) the water takes a longer time to boil.
Q.  Why will a POT (filled with water) IEVER.
BOIL, when immersed in ANOTHER vessel full of water,
also?
A. Because water can never b)e heat —
ed above the boiling poiYnt; all the heat.




114         EFFECTS OF HEAT.
absorbed by water after it boils, is em.
ployed in generating steam.
Q.  How does the conversion of water into steam,
prevent the INNER POT from BOILING?
A. Directly the water in the larger
pot is boiling hot (or 212~), steam is formed and carries off some of its heat; therefore, 212~ of heat can never pass through
it, to raise the inner vessel  to boiling
heat.
Q.  Why do SUGAR, SALT, 4'C., RETARD the process of BOILING?
A. Because they increase the density
of water; and whatever increases the
density of a fluid, retards its boiling.
Q.  If you want water to boil without COMING
IN CONTACT with the SAUCEPAN, what plan must you
adopt?
A. We must immerse the pot (containing the water to be boiled) in a saucepan  containing strong  brine, or sugar.
Q.  WhMy would the INNER vessel boil, if the
OUTER vessel contained strong BRINE?
A. Because brine will not boil, till it
is raised to 218  or 2200.   Therefore,
212~ of l.eat may easily pass through,it, to raise the vessel immersed in it to boiling heat.
Q.  Why will brine impart to another vessel
IIORE than 212~0, and water NOT SO MUCH?




EXPANSION.                 115
A. Because no liquid can impart so
high a degree of heat, as its own boiling
temperature: As water boils at 2120 it
cannot impart 212~ of heat: but, as brine
will not boil without 21~ of heat, it can
impart enough to make water boil.
Q.   Thy can liquids impart no EXTRA heat,
after they boil?
A. Because all extra heat is spent in
making  steam.    Hence  water will not
boil a vessel of water ilmmersed in it, because it cannot impart to it 2120 of
heat; but brine will, because it can impart more than 212~ of heat, before it is
itself converted  into steam.
Ether boils at- - 100 degs. Syrup boils at - - 221 degs.
Alcohol - - - - - 173 "   Oil of turpentine - 314"
Water - - - - - - 212  "   Sulphuric acid - - 472"
Water, with one-         Linseed oil -- -- 640
fifth salt - - 219  "   Mercury - - - 656 "
Any liquid which boils at a lower degree can be made to
boil, if immersed in a liquid which boils at a higher degree.
Thus a cup of ether can be made to boil in a saucepan of
water. A cuLp of water in a saucepan of brine or syrup.
But a cup of water will not boil, if immersed in ether; nor
a cup of syrup in water.
Q.   Why are CLOUDS HIGHERI 0o a FINE DAY?
A.  Because  they   are  lighter, and
more buoyant.
Q.   Why are CLOUDS LIGHTEFR on a FINE DAY 
A. lst-Because the vapor of the
clouds is less condensed; and




116        EFFECTS OF HEAT.
2dly-The air itself (on a fine day)
retains much of its vapor in an invisible
form.
Q.  Why is a CUP put INVERTED into a FRUIT"
PIE?
A.  Its principal use is to hold the
crust up, and prevent it frorn  sinking,
when the cooked fruit gives way under it.
Q.  Does not the cup PREVENT the FRUIT of the
pie firon BOILING OVEr I2
A.  No-it will rather tend to nake it
boil over, as there will be less room in
the dish.
Q.  Explain this.
A.  When the pie is put into the oven
the air in the cup will begin to expand,
and drive every particle of juice from
under it; in consequence of which, the
pie-dish will have a cup-full less room to
hold its fruit in, than if the cup were
taken out.
Q.  If the juice is driven OUT of the cup, why is
the cur always FULL of JUICE when the pie is cut up?
A. Because immediately the pie is
drawn, the air in the cup begins to condense aoain, and occupy a smaller space;
and, as the cup is no longer full of air,
juice rushes in to occupy the void.
Q.  Why does JUICE rush into the cup when the
CUp is NOT FULL of AIR?




EXPANSION FROM  HEAT.           117
A. Because the external air presses
upon the surface of the juice, which rushes
unobstructed into the cup; as mercury
rises through the tube of a barometer.
N. B. Since the juice of the pie runs into the cup, as
soon as it is taken out of the oven; the cup prevents the
juice from being spilt over the crust, when the pie is carried
about from place to place; although it does not prevent
the fruit from boiling over.
CHAPTER XII.
EXPANSION  FROM  HEAT.
( Continued.)
Q.  Does heat expand everything ELSE besides
air and uwater?
A. Yes: every thing (that man is acquainted with) is expanded by heat.
Q.   Why does a cooPER heat his HOOPS RED
HOT when he puts them on a tub?
A.  1st-As iron expands by heat, the
hoops will be larger when they are red
not; in consequence of which, they will
fit on the tub more easily: and
2dly-As iron contracts by cold, the
hoops will shrink as they cool down, and
girt the tub with a tighter grasp.
Q.   Why does a WHEELWRIGHT make the hoop
RED HOT which he fixes on the NAVE of a WHEEL?




118        EFFECTS OF HEAT.
A.  1st-That they may fit on more
tasily: and
2dly-That they may girt the nave
more tightly.
Q.  Why will the wheelwright's HoOP FIT the
nave MORE EASILY,for being made RED HOT?
A. Because it will be expanded by
the heat; and (being larger) will go on
the nave more easily.
Q.  Why will the Hoops which have been PUT
ON HOT GIRT the nave more FIRMLY?
A.  Because they will shrink when
they cool down; and, therefore, girt the
nave fwith a tighter grasp.
Q.  Why does a STOVE make a CRACKLINQ
NOISE when afire is very hot?
A. Because it expands from the heat;
and the parts of the stove rubbing
against each  other, or driving against
the bricks, produce a crackling noise.
Q.  Why does a STOVE make a similar CRACKLING NOISE when a large FIRE is TAKEN DOWN?
A.  Because it contracts again, when
the fire is removed; in consequence of
which, the parts rub against each other
again, and the bricks are again disturbed.
Q.  Why does the PLASTER round a STOVE
CRACK and fall away?
A. Because (when the fire is light
ed) the iron-work expands more than




EXPANSION FROM HEAT.         119
the brick-work and plaster, and pushes
them  awvay; but (when the fire is put
out) the metal shrinks again, and leaves
the "setting" behind.
The "setting" is a technical word for the plaster, &c.,
in immediate contact with the stove.
Q.  Why does the PLASTER FALL AWAY?
A. As a chink is left (between the
"setting" and the stove), the plaster
will frequently fall away from its own
weight.
Q.  What OTHER cause contributes to BRING
the PLASTER DOWN?
A. As the heat of the fire varies, the
size of the iron stove varies also; and this
swelling and contracting keep up such
a constant disturbance about the plaster,
that it cracks and falls off, leaving the
fire-place very unsightly.
Q.  Why does the MERCURY of a THERMOMETER
RISE in hot weather?
A.  Because heat expands the metal,
which (being increased in bulk) occupies
a larger space; and, consequently, rises
higher in the tube.
Q. WMhy is a GLASS BROKEN when HOT WATER
is poured into it?
A. Because the inside of the glass is
expanded by the hot water, and not the




120        EFFECTS OF HEAT.
outside; so the glass snaps, in consequence of this unequal expansion.
Q.  Why is not the OUTSIDE of the GLASS e:
panded by the hot water as well as the INSIDE?
A. Because glass is a bad conductor
of heat, and breaks before the heat of the
inner surface is conducted to the outside.
Q. iVWhy does a GLASS snap because the INNER
surface is HOTTER than the OUTER?
A. Because the inner surface is expanded and not the outer: in consequence of which, an opposing force is
created, which breaks the glass.
Q.  Why is a CHINA CUP broken if HOT WATER
be poured over it, or into it?
A. Because it is a bad conductor;
and, as the inner surface expands from
the heat, (and not the outer,) an opposing
force is created, which breaks the cup.
Q.  If a GLASS BEAKER be set on a warm HOB,
why does the BOTTOM COME OFF?
A.  Because glass is a bad conductor;
and (as the bottom of the glass expands
from the warmth of the hot stove, before
the sides are heated) the two parts separate from each other.




LIQUEFACTION.           121
CHAPTER XIII.
2. —LIQUEFACTION.
3. -VAPORIZATION.
Q.  What is meant by LIQUEFACTION?
A.  The state of being melted; as ice
is melted by the heat of the sun.
Q.   thy is ICE MELTED by the HEAT of the SUN?
A. Because, when the heat of the
sun enters the solid ice, itforces its particles asunder; till their attraction of
cohesion is sufficiently overcome, to
convert the solid ice into a liquid.
See p. 109.
Q.  Why are METALS MELTED by the heat oj
FIRE?
A.  Because, when the heat of the
fire enters the solid metal, itforces its particles asunder; till their attraction of
cohesion is sufficiently overcome, to convert the solid metal into a liquid.
Q.  Why is WATER converted into STEAM by
the heat of the FIRE?
A. Because, when the heat of the
fire enters the water, it separates its
globules into very minute bubbles; which
(being lighter than air) fly off from the
surface in the form of steam.
Q. WWhy does not WOOD MELT like metal?
6




122        EFFECTS OF HEAT.
A. Because the heat of the fire de.
composes the wood into gas, smoke, and
ashes; and the different parts separate
fromn each other.
Q. What is meant by VAPORIZATION?
A.  The conversion of a solid or liquid
into vapor: as snow  or water is converted into vapor by the heat of the
sun.
Q.  What are CLOUDS?
A.  Moisture  evaporated  front the
earth, and again partially condensed in
the upper regions of the air.
Q.  Wrhat is the difference between a FOG and a
CLOUD?
A. Clouds and fogs differ only in
one respect.  Clouds are elevated above
our heads: but fogs come in contact with
the surface of the earth.
Q.  Why do CLOUDS FLOAT SO readily in the air?
A. Because they are composed of
very minute globules (called ves'icles);
which (being lighter than air) float, like
soap bubbles.
Q.  Trhy does VAPOR sometimes form  into
CLOUDS, and sometimes rest upon the earth as MIST
or FOG?
A. This depends on the temperature
of the air.  When the surface of the
earth is warmer than tle air, the, vapor




VAPORIZATION             12?
of the earth (being condensed by the
chill air) becomes mist or fog.   But,
when the air is warmer than the earth,
the vapor rises through the air, and beconmes cloud.
Q.  Are ALL clouds ALIKE?
A.  No. They vary greatly in density,
height, and color.
Q.'What is the chief CAUSE of fog and cLouDS?
A.  The changes of the wind.
Many local circumstances also favor the formation of
clouds.
Q.  hIow can the CHANGES of the WIND affect the
CLOUDS?
A.  If a cold current of wind blows
suddenly over any region, it condenses
the invisible vapor of the air into cloud
or rain: but if a warm  current of wind
blows over any region, it disperses the
clouds, by absorbinge their vapor.
Q.  What COUNTRIES are the MOST cloudy?
A. Those where the winds are most
variable, as Britain.
Q.  What COUNTRIES are the LEAST cloudy?
A.  Those where the winds are least
variable, as Egypt.
Q.  What DISTANCE are the CLOUDS from the
EARTH?
A.  Some thin, light clouds are elevate I above the highest mountain-top;




124        EFFECTS OF HEAT.
some heavy ones touch the steeples,
trees, and even the earth: but the average height is between one and twto miles.
N. B. Streaky, curling clouds, like hair, are often 5 or
6 miles high.
Q.  WHAT CLOUDS are the LOWEST?
A. Those which are most highly electrified; lightning clouds are rarely more
than about 700 yards above the ground;
and often actually touch the earth with
one of their edges.
Q. What is the SIZE of the CLOUDS?
A.  Some clouds are 20 square miles
in surface, and above a mile in thickness;
while others are only a few yards or
inches.
Q.  How can persons ascertain the THICKNESS
of a cloud?
A.  As the tops of high mountains are
generally above the clouds, travellers
may pass quite through them into a clear
blue firmament; when the clouds will
be seen beneath their feet.
Q.  What produces the great VARIETY in the
SHAPE of the CLOUDS?
A.  Three things: 1st-The cause
and manner of their formation:
2dly —Their electrical condition: and
3dly-Their relations to currents of
wind.




VAPORIZATION.            125
Q. Itow can ELECTRICITY affect the SHAPE of
CLOUDS?
A.  If one cloud be full of electricity
and another not, they will be attracted to
each other, and either coalesce-diminish in size-or vanish altogether.
Q.  WHAT CLOUDS assume the most FANTASTIC
shapes?
A.  Those that are the most highly
electrified.
Q.  What effect have WINDS on the SHAPE of
CLOUD?
A.  They sometimes absorb them entirely; sometimes increase their volume
and density; and sometimes changce the
position of their parts.
Q.  fow can WINDS ABSORB CLOUDS altogether?
A.  Warm, dry winds will convert the
substance of clouds into invisible vapor,
which they will carry away in their own
current.
Q.  oIow can WINDS INCREASE the bulk and
density of CLOUDS?
A. Cold currents of wind will condense the invisible vapor of the air, and
add it to the clouds with which they
come in contact.
Q.  How can winds CHANGE the SHAPE of
CLOUDS, by altering the position of their parts?
A.  Clouds are so voluble and light,




126         EFFECTS OF HEAT.
that every breath of wind changes the position of their ves'icles or bubbles.
Q.   What are the general cOLORS of the
CLOUDS? 
A. White and grey, when the sun is
above the horizon: but red, orange, and
yellow, at sun-rise and sun-set.
The blue sky is not cloud at all.
Q.  tWhy are the LAST CLOUDS of EVENING generally of a RED tinge?
A.  Because red rays (being the least
refrangible of all) are the last to disappear.
Do
Suppose P A to be the red rays, P B the yellow, P C
the blue. If the earth turns in the direction of P A D, it
is quite manifest that a spectator will see A, (the red rays,)
some time after P C and P B have passed from sight.
Q.   WhMat is meant by being " LESS REFRANGIBLE'?
A.  Being less able to be bent.  Blue
and yellow rays are more easily bent
beloiw the horizon by the resistance of the
air: but red rays are not so much bent




VAPORIZATION.             127
down; and, therefore, we see them  later
in the evening.o
As at A in the figure on p. 126.
Q.  WThy are MORNING CLOUDS generally of a
RED tinge?
A. Because red rays are the least refrangible of all; and not being bent so
much as blue and yellow rays, we see
them sooner of a morning.
Thus (fig. on p. 126) if the earth turned in the direction
of D A P, a spectator at D would see A (the red rays) long
before he saw P B and P C.
Q.  TIVhy is not the color of clouds always ALIIKE?
A.  Because their size, density, and situation in reegard to the sun, are perpetually varying; so that sometimes one color is reflected and sometimes another.
Q.   What regulates the MOTION of the CLOUDS?
A.  Priincipally tile winds; but sometimes electricity will influence their motion also.
Q.  Hlow do you know that CLOUDS move by
OTHER i?/l7tuences besides WIND?
A. Because (in calm weather) we
often see small clouds meeting each other
fiom opposite directions.
Q.  lHow. do you know that ELECTRICITY affect
the motion?f the clouds?
A.  Because clouds often meet from
opposite directions; and, having discharg



128         EFFECTS OF HEAT.
ed their opposite electricities into each
other, vanish altogether.
Q.  Into how many cLAssEs are the diferend
sorts of CLOUDS generally divided?
A.  Into three classes:-viz. Simple,
Intermediate, and Compound.
Q.  How are SIMPLE CLOUDS sub-divided?
A.  Into  1.-Cirrus; 2. —Cun'ulus;
and 3.-Stra'tus clouds.
Q.  What sort of CLOUDS are called CIRvus?
A.  Clouds like fibres, loose hair, or
thin streaks, are called " cirrtus clouds."
Q.  T:Irhy are these clouds called cirnus?
A.  From  the Latin word cirrits (" a
lock of hair, or curl").  Cirrus clouds
are the most elevated of'all.
Q.  TWhat do CIRnus clouds rorTEND?
A.  When  the  streamers  point zpwards, the clouds are fllin(g, and rain is
at hand: but when the streaimers point
downwards, westerly  winds or drought
may be expected.
Q.  1Vhat sort of CLOUDS are called CUM'ULUS?
A.  Cum'ulus clouds are  ilumps, like
great suzar-loaves-voltnes (?f smokeor nmountains towzering over notuctains.
Q.   TV7hy are these monster masses called CUM'ULUS CLOUDS?
A.  From  the Latin word  calnt'alus
"a mnass or pile ").




VAPORIZATION.            129
What Edo CUM'ULUS clouds FORESIIOV?
A. Wlen these piles of cloud are
fleecy, and  sail against the wind, they
indicate rain; but when their outline is
very hard, and they come up with the
wind, they foretell fine weather.
Cum'ulus clouds should be smaller towards evening
than they are at noon. If they increase in size at sun-set,
a thunder-storlm mlay be expected in the night.
Q.  What sort of CLOUDS are called STRA'TUS?
A.  Creeping ntists, especially prevalent in a su-mmer's evening: these clouds
rise at sun-set in low, damp places; and
are always nearer the earth  than  any
other sort of cloud.
Q.  WIVhy are these mists called STRA'TUS clouds?
A.  From  the  Latin  word  stra'tus
(" laid low," or " that which lies low").
Q.   XTWhat produces CIRRUS CLOUDS?
A.  Moisture in a visible form, deposited in the hiigher regions of the atmosphere by ascending currents of heated air.
Q. What produces CUM'ULUS CLOUDS?
A. Masses of visible vapor passing
from the places where they wereformed,
to other places where they are about to
be either dissolved, or deposited as falling
rain.
Q.  WUrhat produces STRA'TUS CLOUDS?
A.  Beds of visible moisture, formed
6*




130         EFFECTS OF HEAT.
by some chilling effects, acting along the
direct surface of the earth.
Q.  How are the INTERMEDIATE CLOUDS Sb-di
vided?
A.  Into two  sorts.  1.-The CirroCum'ulus; and 2.-The Cirro-Stra'tus.
Q.   W-hat are CIRRO-CUM'ULUS CLOUDS?
A.  Cirro-Cum'ulus clouds are cirrus
clouds springing  fi'omn a massy centre,
or hearvy nmasses, edged with long( streaks
generally called "mares' tails."
A system of snmall round clouds may be called cirru
cuml'ulus.
Q.  What do CIRRO-CUM'ULUS clouds generalt
FOREBODE?
A. Continued drought, or hot, dry
weather.
Q.  Wt[hat are CIrnO-STRA TUS CLOUDS?
A.  They compose what is generally
called a " nzackarel sky."  This class of
clouds invariably indicates rain and
wind; hence the proverb" AMackarel's scales and mares' tails
MIake lofty ships to carry low sails."
Q.  W71hat produce CIRRO-CUM'ULUS clouds?
A.  Cttunttlus clouds diss,)lving away
into cirrus produce the intermediate class
called CIRRO-CUM'ULU.s.
Q.  What produce CIRnRO-STRA TUS clouds?
A    Cirrus clouds accumulatingr into




VAPORIZATION.            131
denser masses produce the intermediate
class, called CIRRO-STRA'TUS.
Q. How are COMPOUND CLOUDS sub-divided?
A. Compound clouds are also subdivided into two sorts. 1.-The Cum'ulo-Stra'tus; and 2.-The Nimbus clouds.
Q.  lVhat is meant by CUMULO-STRA'TUS clouds?
A. Those clouds which assume all
sorts of gigantic forms; such as vast
towers and  rocks-huge  whales and
dragons-scenes of battle —and cloudy
giants. This class of clouds is the most
romantic and strange of all.
Q.  What do the CUMULO-STRA'TUS clouds
FORETELL?
A. A change of weather; either from
fine to rain, or from rain to fine.
Q.  What are NIMBUS CLOUDS?
A.  All clouds from which rainfalls.
Nimbus is the Latin word for "clouds
which bring a storm."
Q. By what particular character may the
NfIBUS (or rain-cloud) be at once DISTINGUISHED?
A. By the want of a defined outline:
Its edge is gradually shaded off from the
deep grey mass into transparency.
Q.  ]What APPEARANCE takes place in the CLOUDS
at the approach of RAIN?
A    The cum'ulus cloud becomes sta.




132        EFFECTS OF HEAT.
tionary, and cirrus streaks settle upon it,
forming cum'ulo-stratus clouds; black at
first, but afterwards of a grey color.
Q.  Why do CLOUDS gather rOUND IOUNTArN
TOPS?
A.  Because the air (being chilled by
the cold mountain tops) deposits its vapor there in a visible form or cloud.
Q.  What are the USES of CLOtUDS?
A.  1st-They  act as screens, to ali
rest the radiation of heat from the earth;
2dly-They temper the heat of the
sun's rays; and
3dly-They are the great store-houses
of rain.
"' Radiation of heat," i. e., the escape of heat, when no
comductor carries it away.
Q.  WMIy is WIND said to BLOW UP the CLOUDS?
A. Because a dry, warnm wind (which
has travelled over seas) having absorbed
a large quantity of moisture, deposits
some of it in the visible forme of clouds,
as soon as it reaches a colder region of
air.
Q.  Why does WIND sometimes DRIVE AWAY thd
CLOUDS?
A. Because it has travelled over dry
climes or thirsty deserts, and become so
dry, that it absorbs vapor from the
clouds, and causes them to disappear.




VAPORIZATION.              133
Q. What is the CAUSE of a RED SUN-SET?
A. The vapor of the air, not being
actually condensed into clouds, but only
Dn the point of being condensed.
Q.   Why is a RED SUN-SET an indication of a
FINE DAY to-morrow?
A. Because the vapors of the earth
are not condensed into clouds, by the cold
of sunset. Our Lord referred to this
prognostic  in  the   following  words:
"When it is evening ye say it will be
fair weather, for the sky is red." (Matt.
xvI. 2.)
Q.   What is the cause of a coppery YELLOW
SUN-SET?
A. The vapor of the air being actually condensed into clouds.
Q.  Why do vapors (NOT ACTUALLY CONDENSED)
refract RED rays, while condensed vapor refracts
yellow?
A. Because the bearns of light meet
with very little resistance; in consequence of which, those rays are bent
down to the eye, which require the least
refraction, such as red.
See figure on p. 126, where it is evident that the red ray
P A, is less bent, than the yellow and blue rays, P B, P C.
Q.   Why do CONDENSED vapors refract YELLOW rays, whereas vapors not actually condensed
refract red?
A. Because the beams of light meet




134        EFFECTS OF HEAT.
with more resistance from the condensed
vapor; in consequence of which, those
rays are bent down to the eye, which are
more refracted than the red, such as yellow.
See on figure p. 106, where it is evident that the yellow
ray, P B, is more bent than the red ray, P A.
Q.  WYhy is a YELLOW SUN-SET an indication
of WET? 
A. Because it shows that the vapors
of the air are already condensed into
clouds; rain, therefore, may be shortly
expected.
Q.  WZhat is the cause of a RED SUN-RISE?
A. Vapor in the upper region of the
air jwst on the point of being condensed.
Q. WTYy is a RED and LOWERING sky at SUNRISE an indication oJ' a WET DAY?
A. Because the higher regions of the
air are laden with vapor on the very
point of condensation, which the rising
sun cannot disperse. Hence our Lord's
observation, " In the morning ye say, it
will be foul weather to-day, for the sky
is red and lowering." (Matt. xvI. 3.)
Q.  Why is a GR1EY MORNING an indication of
a FINE DAY?
A. Because only the air contiguoaus to
the earth is damp  and  full of vapor.
There are no vapors in the hirher re



VAPORIZATION.              135
gions of thle air, to bend down to the eye
even the red rays of any beam  of light.
Q.'What difference (in the state of the air) is
required, to make a GREY and RED SUN-RISE?
A. In a grey sun-rise, only that portion of air contiguous to the earth is filled
with vapor; all the rest is clear and dry.
But in a red sun-rise the air in the upper
regions is so full of vapor, that the rising
sun cannot disperse it.
Q.   Why is a GREY SUN-SET an indication
of WET?
A. Because it shows that the air on
the surface of the earth is very damp at
sun-set; which is a plain proof that the
air is saturated  with vqapor;  in  consequence of which wet may be soon expected: hence the proverb"Evening red and morning grey
Will set the traveller on his way;
But evening grey and morning red
Will bring down rain upon his head."
Q.  lW[hat is meant by an AURORA BOREA'LiS1
or northern light?
A.  Luminous clouds in the north of
the sky at night-tirne.  Sometimes streaks
of blue, purple, green, red, &c., and
sometimes flashes of light, are seen.
Q.   What is the cause of the AURORA DOREA'LIS, or northern light?




136        EFFECTS OF HEAT.
A. Electricity in the higher regions
of the atmosphere.
Q.  Why are there DTFFERENT COL )RS in the
Aurora Borea'lis, such as white, yellow, red and
purple?
A.  Because the electric fluid passes
through air of different densities.  The
most rarefied air produces a owhite li4ghlt;
the most dry air, red; and  the  most
damp produces yellow streaks.
Q.  Does the AURORA BOREA LIS forebode fi7e
weather or xw\ET?
A. When its coruscations are very
bright, it is generally followed by unsettled weather.
Q.  Why does a HAZE round the SUN indicate
RAIN?
A. Because the haze is caused by
very fine rain falling in the upper regions
of thle air: when this is the case, a rain
of 5 or 6 hours' duration may be expected.
Q.  Why is a HALO round the MOON a sue indication of RAIN?
A. Because it is caused by fine rain,
falling in the upper regions of the air.
The larger the halo, the nearer the rainclouds, and the sooner may rain be expected.
Q.  What is the cause of a BLACK MIST: and
why does it bringL WET weather?




WEATHtER.            137
A. The mist is black, because it is
overshado'wed by dense clouds; and twet
weather may be expected, because the
air is saturated with vapor.
Q.  Why is MIST sometimes WHITE: and why
does a while mist indicate FINE weather?
A. The mist is vwhite, because no
clouds blackenz it with their shadozw; and
fine weather may be expected, because
the sky is cloudless.
Q.  WIhy do we FEEL almost SUFFOCATED in a
hot cloudy night?
A.  Because the heat of the earth
cannot escape into the upper region of
the air; but is pent in by the clouds,
and confined to the surface of the earth.
Q.  TWhy do we feel SPnIGHTLY in a clear,
bright ni, ght?
A.  Because the heat of the earth can
readily escape into the upper regions of
the air, and is not confined and pent in
by thick clouds.
Q.  W7hy do we FEEL DEPRESSED in SPIRITS on
l, WET, murky DAY?
A.  Ist-Because the  air is  laden
wvith vapor, and has (proportionally) less,xygen.
2dly-The air being lighter than usual,
toes not balance the air iln our body; and




138         EFFECTS OF HEAr.
3dly-Moist air has a tendency to depress the nervous system.
Q.  W7Mat is meant by the "air balancing the
air in our body?"
A. The human body contains air of
a given density; if, therefore, we ascend
into rarer air, or descend into denser, the
balance is destroyed, and we feel oppressed.
Q.  Wrhy do we feel OPPRESSED, if the air
around is not of the SAME DENSITY as that in our
body?
A. Because if the air be more dense
than our body, it will produce a feeling
of oppression; if it be less dense, the air
in our body will produce a feeling of
distension.
Q.  W'hy do PERSONS, who ASCEND in BALLOONS, FEEL PAIN in their eyes, ears, and chest?
A. Because the air in the upper regions of the atmosphere is more rare
than the air in their bodies; and (till
equilibriunm is restored) pain will be felt in
the more sensitive parts of the body.
More especially in the tympanum of the ear.
Q.  Why do PERSONS, who DESCEND in DIVINGBELLS, FEEL PAIN in their eyes, ears, and chest?
A. Because the air in the diving-bel.
is comnpressed by the upward pressure of
the water; in consequence of which,




WEATHER.               139
fgreat pain is felt in the more sensitive
parts of the body.
The presstre thus caused is sometimes sufficient to ru<i4
ture the membrane of the tympanum, and produce incurable dcafnbess.
Q. Why are PEARL DIVERS very frequently
DEAF 2
A.  Because the pressure qf the water
against the tympanum of their ears ruptures the membrane; and this rupture
produces incurable deafness.
Q.  Why does the SEA HEAVE and SIGH, aust
PREVIOUS to a STORM?
A. Because the density of the air
is very suddenly diminished; and (as the
density of the air is diminished) its power to transmit sound is diminished also;
in consequence of which, the roar of the
sea is less audible, and seems like heavy
sighs.
Q.  Why is the AIR SO universally QUIET, just
PREVIOUS to a TEMPEST?
A. Because the air is suddenly and
very greatly rarefied; and (as the density
of the air is diminished) its power to
transmit sound is diminished also.
Q.  How do you KNOW, that RAREFIED air
CANNOT TRANSMIT SOUND SO well as dense air?
A. Because the sound of a bell, (in
the receiver of an air-pump) can scarcely




140         EFFECTS OF HEAT.
be heard, after the air has been partially
exhausted; and the report of a pistol
(fired on a high mountain) would  be
scarcely audible.
Q.  Wlhy do we FEEL BRACED and LIGHTHEARTED on a FINE spring or FROSTY morning?
A.  1st-Because there is more oxy.
gen in the air on a fine frosty morninog
than there is on a wet day: and
2dly-A  brisk and frosty air has a
tendency to brace the nervous system.
Q.  Why do DOGS and CATS (coiljined to a
room) feel LAZY and DROWSY, at the approach of
rain?
A. 1st-Because the air does not
contain its full proportion of oxygen; and
2dly-The damp depresses their nervous system, and makes them  drowsy.
Q.  When SHEEP lie under a HEDGE, and seem
unwilling to go to pasture, RAIN is at hand: Ex.
plain the reason of this.
A. 1st-As the air does not contain
its full proportion of oxygen, they feel
uneasy; and
2dly-As the damp  air relaxes their
nervous system, they  feel listless and
drowsy.
Q.  Irhy do HORSES neigh, CATTLE,,Oy, SHEEP
bleat, and ASSES bray, at the approach of rain?
A.  1st-As the air does not contain




WEATHER.              14t
its full proportion of oxygen, they feel
a difficulty in breathing; and
2dly-As damp relaxes their nerves,
they feel languid and uneasy.
Q.  Mention some OTHER ANIMALS. which indicate the approach of rain in a similar way.
A. When pigs squeak, as if in great
pain-frogs croak with a loud, hoarse
noise-owls screech-woodpeckers cry
-peacocks scream-guinea-fowls squall
-or ducks and geese are unusually
noisy, rain is close at hand.
Q.  Why do CANDLES and FIRES burn with a
BLUER FLAME in wet weather?
A. Because the air contains less oxygen in wet weather, and therefore, the
heat of fire is less intense: The flame is
blue, because the fuel is not thoroughly
consumed.
Q. Why do HILLS, C.c., appear LARGER in
WET weather?
A.  Because the air is laden with vapor,
which causes the rays of light to diverge
more; in consequence of which, they produce on the eye larger images of objects.
Q.  Wthy do TREES, Cjc., in WET weather ap
pear FURTHER OFF than they really are?
A.  Because the fog or mist diminishes the light reflected from the object; and




142        EFFECTS OF HEAT.
as the object becomes more dinzm, it seems
to be further off.
Q.  Why do CATS RUB their EARS, when it is
likely to rain?
A. Either because the air is full of
vapor, and its humidity (piercing between
the hair of the cat) produces an itching
sensation: or more probably,,because the
air is overcharged with electricity.
Q.  How can the ELECTRICITY of air produce a
sensation of ITCHING?
A. If the air is overcharged with
electricity, the hair of the cat is overcharged also; and this makes her feel
as if she were covered with cobwebs.
Q.  Why does the CAT keep RUBBING herself?
A.  Because her hair will not lie
smooth, but has a perpetual tendency to
become turgid and nuffled; so the cat
keeps rubbing her coat and ears, to
smooth the hair down, and brush away
the feeling of cobwebs.
Q.  Why do our HEADS and SKIN itch befor&
rain?
A. Probably because the air is overcharged with electricity; and, therefore.
a sensation (like that of cobwebs) irritates the skin, and produces an itching.
Q.  When the plants called TREFOIL: DANDE




WEATHER.               143
LION, PIMrPERNEL~,'c., FOLD Up their 7eaves, RAIN is
qlways close at hand: Explain this.
A. Ist-The cloudy weather diminishes the light of the sun; and without
the stimulus of sun-light, these flowers
never open their leaves.
2dly-The vapor of the damp air, in.
sinuatingc itself into the air-vessels of
these delicate plants, causes themt to
expand; in consequence of which, the
leaflets contract and close.
All these plants close at sun-set also.
Q.  TIMiy do DOORS SWELL in RAINY weather?
A.  Because the air is filled with vapor, which (penetrating into the pores of
the wood) forces the parts farther apart,
and swells the door.
Q.  Why do DooRS SHRINK in DRY weather?
A.  Because the moisture is absorbed
from the wood; and, as the particles are
brought closer together, the size of the
door is lessened-in  other words, the
wood shrinks.
Q.  MWhy is the AIR filled with ofensive SNIELLS:
just previous to a coming RAIN?
A. Because the volatile parts which
rise from dunghills, sewers, &c., are prevented (by the vapor of the air) from
rising so readily, as when the sun is
shining brightly.




144         EFFECTS OF HIEAT.
Q.  Why do FLOWERS smell SWEETEl. arm
STRONGER, just previous to RAIN?
A. Because the volatile parts which
constitute the perfume of flowers, are
prevented (by the vapor of the air) from
rising; in consequence of which, they
are confined to the lower regions of the
atmosphere.
N. B. Many essential oils and other volatile substances,
which produce odors in plants, require the presence of
much moisture for their perfect development.
Q.  Why do HORSES and other animals stretch
out their necks, and SNUFF up the AIR, just previous
to a fall of RAIN?
A.  Because they smell the odor of
plants and hay, and delight to snuff in
their fragrance.
Q.  Why does SMOKE FALL, when RAIN is at
hand?
A. Because the air is less dense, and
cannot buoy up the smoke so readily as
dry and heamy air.
Q.  Why do SWALLOWS FLY LOW, when RAIN
is at hand?
A. Because the insects (of which they
are in pursuit) have fed from  the cold,
upper regions of the air, to the warm  air
near the earth; and, as theirfood is low,
the swallows fly lozo.
Q.  Why do these INSECTS seek the lower regions




FOUL WEATHER.            145
of the air in WET weather, more than in TINE
weather?
A.  Because  (in wet weather) the
upper regions of the air are colder than
the lower; and, as insects enjoy warmth,
they seek it near the earth.
Q.   Ih/q/ does a DOWNWARD current of COLD
AIR bring rtAI.N?
A.  Becaulse it condenses the warm
vapor;  which (being  condensed) descends in rain.
Q. The ~proL0erb says, " A SINGLE MAGPIE in
spring, FOUL WEATHER will bring:" WVhy is this
the case?
A. Because in cold, stormy weather,
one magpie alone will leave its warm,
snug nest ill search of food, while the
other stays with the egs, or young ones;
but in fi;e, mild weather (when their
brood will not be injured by cold) both
the magpies fly out logether.
Q.  ITT7y is it UNLUCKY for ANGLERS to see a
SINGLE MAGPIE in spring?
A.  Because when magpiesfly abroad
singly, the weather is cold and stormy;
but, when both birds fly out together, the
weather is wvarm  and mild, which is
favorable for fishing.
Q.  VWhy do SEA-GULLS fly about the SEA si
FINE weather?
7




146         EFFECTS OF HEAT.
A.  Because they live upon the fishes,
which are found near the surface of the
sea in fine weather.
Q.  ISVhy may we expect STORMY RAINS, when
SEA-GULLS assemble on the land?
A. Because the fishes (on'which
they live) leave the surface of the sea in
stormy weather, and are beyond the
reach of the sea-gulls; in consequence
of which, they are obliged to feed on the
worins and larvae, which are driven out
of the gr'ound at such times.
Larvae, little grubs and caterpillars.
Q.  W[hy do PETRELS fly to the SEA during a
storm?
A.  Because they live upon sea insects,
which are always to be found in abundance about the spray of swelling waves.
N. B. Petrels are birds of the duck-kind, which live in
the open sea. They run on the top of the waves, and are
called Petrels, or rather Peter-els, from " St. Peter," in
allusion to his walking on the sea, to go to Jesus.
Q.   Why do CANDLES and LAMPS SPIRT, when
RAIN is at hand?
A.  Because the air isfilled wvith vapor
which penetrates the wick; where (being
formed into steanz) it expands suddenly,
and produces a little explosion.
Q.  Why does a DrnOP of WATER sometimes ROLL
along a piece of hot iron, without leaving the leasi
trace?




VAPOR.               147
A. Because the bottom of the drop is
turned into vapor, which buoys the drop
up, without allowing it to touch the iron.
Q.  ]Why does it ROLL?
A. Because the current of air (which
is always passing over a heated surface)
drives it along.
Q.  WVhy does a LAUNDRESS put a little SALIVA
on a FLAT-IRON, to know if it be hot enough?
A. Because whlen the saliva sticks to
the box, and is evaporated, she knows it
is not sufficiently hot; but, when it runs
alone the iron, it is.
Q. Why is the FLAT-IRON 1HOTTER if the saliva
RUNS ALONG it, than if it adheres till it is evaporated?
A.  Because  when  the saliva runs
alonzg the iron, the heat is sufficient to
convert th/e bottoml of the drop inrto vapor;
but, if the saliva will not roll, the iron is
not sufficiently hot to convert the bottom
of the drop into vapor.
CHAPTER XIV.
4.-EVAPORATION.
Q.  What is meant by EVAPORATION?
A. The dissipation of liquid by its
conversion into vapor.




148          EFFECTS OF HEAT.
Q.  WThat EFFECTS are produced by ev:aporation?
A.  rThe liquid vaporized tabsorbs heal
from the body whence it issules; and the
body dlerived of the liquid by evaporation, loses heat.
Q.  If you WET your FINGEr, in7 your mouth,
and hold it up in the air, why does it FI,:EL COLD?
A.  Because the saliva quickly evaporates; aind (as it evaporates) absorbs
heatfinom  thefi-cnger, making it feel cold.
Q.  lf you BATHE your TEMPLES - wlith ether,
why does it allay TINFLAMMIATION anld fu'verish heat?
A.  Because ether very rapidly evaporates; and (as it evaporates) absorbs heat
from the burning head, producing( a sensation of cold.
Q.   TVhy is ETHER better for this purpose than
WATER?
A.  Because ether requires less heat
to convert it into vapor; in collsequence
of which, it evaporates more qui/ckly.
N. B. Ether is converted into vapor with 1000 of heat:
but water reqluires 21i2 of heat to conve:'t it into steam.
Q.   Ilhty does ETIIER very greatly rELIEVE a
SCALD or BUJriN?
A.  Because it evaporates very rapidly;
and (as it evaporates) carries off tlhe heat
of the burn.
Q.   WA:hy do we FEEL COLD, whent we have WET
FEET or CLOTHES?
A. Because the wet of our shoes or




DAMP CLOTHES.           149
clothes rapidly evaporates; and  (as it
evaporates) absorbs heat front our body,
which makes us feel cold.
Q.  Why do WET FEET or CLOTHES give us
{ COLD?"
A. Because the evaporation absoirbs
heat so abundantly fromn the surface of
our body, that its temperature is lowered
below  its natural standard; in consequence of which, health is injured.
Q.  Why is it DANGEROUS to SLEEP in a DAMP
BED?
A. Because the heat is continually
absorbed fi'orn the surface of our body,
to convert the damp of the sheets into vapor; in consequence of which, our animal heat is reduced beloto the healthy
standard.
Q.  Why is HEALTH INJURED, when the TEMPERATURE of the BODY is REDUCED below its natural
standard?
A.  Because the balance of the circulation is destroyed.  Blood is driven away
from  the external surface by the chill,
and  thrown upon the internal o:gans,
which are oppressed by this increased,
load of blood.
Q.  WVhy do we not feel the same sensation of
cold, if we throw a MACINTOSH over our WEI
CLOTHES?




150        EFFECTS OF HEAT.
A.  Because the macintosh (being air
tight) prevents evaporation; and (as the
wet cannotl evaporate) no heat is absorbed
from our bodies.
Q.  TW;hy do NOT SAILORS get COLD, who are
frequentlgy wet all day with SEA-WATERI 
A.  1st-Because the salt of the sea
retards evraporation; and (as the heat of
their body is drawn off gr'adally) the
sensation of cold is prevented.
2dly-The salt of the sea acts as a
stimulant, and keeps the blood circulating in the skin.
Q.  WThy does SPRINKLING a IIOT ROOM With
water COOL IT?
A. Because the heat of the room
causes a rapc'id evaporation of the sprinkled wcater: and as the watel evaporates,
it absorbs heat front the rvoom, which
cools it.
Q.  TW'hy does WATERING Zhe STRFEETS and
roads CoorL TIIEM?
A. Because they part with their heat
to promote the evaporation of the water
sprinklec on them.
Q.  lWrhy does a SHOWER of RAIN COOL the AIR
-in summer-tine?
A. Because the wet earth ])arts?with
its heat to pronote evaporation; and when
the earth is cooled, it cools the air also.




EVAPORATION.             151
Q.   V7ly is LINEN DRIED by being exposed to
the WIND?
A.  Because  the  wind  accelerates
evaporation, by removing the vapor from
the szrjace of the twet linen, as fast as it
is formed.
Q.  WHrl"y is LINEN DrIyED sooner in the open
AIR, than in a conJfined room?
A. Because the particles of vapor are
more rapidly removed from the surface
of the linen by evaporation.
Q.  Trhy are WET SUMMERS generally sucCEEDED by COLD WINTEnS?
A. Because the great evaporation
(carried on through  the wet summer)
reduces the temperature of the earth loiwer
than usual, and produces cold.
Q.  TVhy is THIS COUNTRnY WARIIME  and the
winters less severe than formerly?
A.  Because it is better drained and
oetter cultivated.
Q.  IVhy does DRAINING land promote WVARMTH?
A.  Because it dliminieshes evaporation,
in consequence of which, less hecat is abstracted from thle earth.
Q.   Wh7y  does CULTIVATION  increase  the
WARMTH of a country?
A.  1st-Because hedgecs and belts of
trees are multiplied:
2dly-The land is better drained: and




152        EFFECTS OF HEATr.
3dly -The vast forests are cut down,
Q.  Why do HEDGES and BELTS of TREES pro.
note XVWArMTH?
A.  Because they retard evapwratlion,
by keeping off the wind.
Q.  _ bellts of trees promote WArIwaTH, why do
FORESTS pvroduce COLD?
A.  ist —Becausoe  they  detain  and
condense the passing clouds;
2dly-They  prevent the access of
both wind and sun;
3dly-The  soil of forests is always
covered with long, daCnp grass, rotting
leaves, and thick brushwvood; and
4thly-In  every forest there are always many hollows full of stagnant
water.
Q.  Why do LONG GRASS and ROTTING LEAVES
promote COLD?
A.  Because they are always damp.
and evaporation, which they promote, is
constantly absorbing heat fiom the earth
beneath.
Q.  WWhy are FRANCE and GEnrMANY WARMER
now, than wheL the vine uwould not rip;en there? 
A. Chiefly because their vast forests
have been cut down; and the soil is better drained and cultivated.
Q.  Wthat becomes of the WATER of PONDS and
rUBs in summer-ime?




EVAPOR ATION.           153
A.  Ponds and tubs are often left dry
in surnmer-tihne, because their water is
evaporatcd by the air.
Q.  HIow is this EVAPORATION PRODUCED and
carried on?
A.  The heat of the air chances the
surface of the water into vapor, which
(blending w ithll the air) is soon wafted
away; and similar evaporation is repeatedly produced, till the pond or tub is
left quite dry.
Q.  WThy are the WHEELS of some machines
kept CONSTANTLY WVET with WATERt?
A.  To carry off (by evaporation) the
heat which arises fiom the rapid motion
of the wheels.
Q.  Why is /MOULD HARDENED by the SUN?
A.  Because  the  moisture  of the
mould is exhaled by evaporation; and,
as the earthy particles are brought closer
together, the mass becomes more solid.
Q.  Show the WISDOM of GOD in this arrangement.
A.  If the soil did not become crusty
and hard in dry weather, the heat and
drought would pentetrate the soil, and kill
both seeds and roots.
Q.  Why is TEA cooled FASTER in a SAUCER
than in a cup?
A.  BeRause evaporation is increased
7*




154         EFFECTS OF HEAT.
by inc reasing the surface; and, as tea in
a saucer presents a lagcr surface to the
air, its heat is more rapidly carried off
by evaporation.
(The subject of " convection" will be treated of in a fauture chapter; it would scarcely be understood in this
place. See p. 213.)
Q.  Why is not the VAPOR of the SEA SALT?
A. Because the salt is always left
behind, in the process of evaporation.
Q.  What is that WHITE CRUST, which appears
(in hot weather) uporn CLOTHES wetted by sea water?
A.  The salt of the wtater, left on the
clothes by evaporation.
Q.   Why does this WHITE CRUST always DISAPPEAR in WET weather?
A.  Because  the nmoisture of the air
dissolves the salt; in consequence of
which, it is no longer visible.
Q.  Why should NOT persons, who take violent
exercise, WEAR very THICK CLOTHING?
A. Because it prevents the perspiration from evaporating.  When the heat
of the body is increased by exercise, perspiration ireduces the heat (by evaporation) to a healthy  standard;  as  thick
clothing prevents this evaporation, it is
injurious to health.




CONDUCTION.            155
COMMUNICATION OF HIEAT.
CHAPTER XV.
1-CONDUCTION.
Q.  f:lbw is HEAT COMMUNICATED from one body
to another?
A.  1.-By Conduction. 2.-By Absorption.  3.-By  Reflection.   4-By
Radiation. And 5.-By Convection.
Q.  What is meant by CONDUCTION of heat?
A. Heat communicated from one
body to another by actual contact.
Q.  Why does a PIECE of WOOD (blazing at
ONE end) NOT feel HOT at the OTHER?
A.  Because wood is so bad a conductor, that heat does not traverse freely
through it; hence, though one end of
a stick be blazing the other end may be
quite cold.
Q.  Why do SOME THINGS feel COLDER than
others?
A. Principally because they are better conductors; and draw off heat from
our body much faster.
Q.  T'hat are the BEST CONDUCTORS of HEAT?
A. Dense, solid bodies, such as metal
and stone.




156     COMMUNICATION OF HEAT.
Q.  VWhich METALS arTe the most RAPID CONDUCT.
ORS of HEAT?
A. The best conductors of heat are
1. gold, 2. silver, 3. copper:
The next best are 4. plat'inum, 5. iron,
6. zinc, 7. tin. Lead is a very inferior
conductor to any of the preceding metals.
Q.   W/that are the WORST CONDUCTORS f IIEAT?
A.  All light and poroets bodies; such
as hair, fur, wool, charcoal, and so on.
Two of the worst conductors known are hare's fur and
eider down;-the two next worst are beaver's fur and raw
silk;-then wood and lanp-black; —theln cotton and fine
lint; —then charcoal, wood ashes, &c.
Q.  Why are COOKING VESSELS often furnished
with WOODEN HANDLES?
A.  Because wvood is not a good conductor, like metal; and, therefore, zwooden,
handles prevent the heat of the vessel
from  rushing into our hands, to burn
them.
Q.  Why is the HANDLE of a METAL TEA-POT
made of WOOD? 
A.  Because wood is a bad conductor;
therefore, the heat of the boilin( water
is not so quickly conveycd to our hand by a
wooden handle, as by one made of metal.
Q.  Why would a METAL HANDLE BURN thd
IIAND of the tea-maker?
A.  Because metal is an excellent conductor; therefore, the heat of boiling wa.




IETTLE-HOLDERS.           157
ter would rush so quickly into the zmetal
handle, that it would burn our hland.
Q.  _Prove that a METAL IIANDLE would be HOTTER than a WOODEN ONE.
A.  If we touch the imetal collar into
which the wooden handle is fixed, we
shall find that the wooden handle feels
cold, but the metal collar intensely hot.
Q.  WThy do persons use paper or WOOLLEN
KETTLE-HOLDERS?
A. Because paper and woollen are
both very bad conductors of heat; in consequence of which, the heat of the kettle
does not readily pass through thenz to the
hand.
Q.  Does the heat of the boiling kettle NEVER
get through the woollen or paper kettle-holder?
A.  Yes; but though the kettle-holder
became as hot as the kettle itself, it
would neverfeel so hot.
Q.  Why would not the kettle-holder FEEL SO hot
as the kettle, when both are of the same temperature?
A. Because it is a very bad conductor, and disposes of its heat too slow2ly to
be. perceptible; but metal (being an excellent conductor) disposes of its heat so
quickly, that the sudden influx is painful.
Q.  Why does HOT METAL FEEL MORE intensely
WARM than HOT %WOOL?
A. Because metal gives out. a nluch




i58    COMMUNICATION OF HEAT.
g-reatcr quatntity of heat in the samne space
of time; and the influx of heat is, consequently, more perceptible.
Q.  Why does MONEY in our pocket feel very
HOT when we stand BEFORE a FrIRE?
A.  Because metal is an excellent conductor, and becomes rapidly heated.
For the same reason, it becomes rapidly
cold, whenever it comes in contact with
a body colder than itself
Q.  Why does a PUMP-IIANDLE feel intenzsely
COLD in WINTER?
A. Because it is an excellent conductor, and draws off the heat of our hand
so rapidly, that the sudden loss produces
a sensation of intense coldness.
Q.  Is the iron HANDLE of the pump really
COLDER than the wooden PUMi itself?
A. No; every inanimate substance
(exposed to the same temperature) possesses in reality the same decgree of heat.
Q.  Why does the IRON HANDLE seemnt so MUCH
COLDER than the WOODEN PUMP? 
A. Merely because the iron is a better conductor; and, therefore, draws'off
the heat from our hand more rapidly
than wood does.
Q.  Why does a STONE or marble HEARTH feel
to thefeet COLDER than a CARPET or hearth-rug?
A. Because stone anld marble are good




CARPETS-STONES.             159
conductors;  but  woollen  carpets  and
hearth-rugs are very bad conductors.
Q.  How does the STONE HEARTH make our
FEET -OLD?
A.  As soon as the hearth-stone has
absorbed a portion of heat from our foot,
it instantly disposes of it, and calls for a
fresh sujpply; till the hearth-stone has become of the same temperature as the foot
placed upon it.
Q.  Do not also the woollen CARPET and HEARTHRUG conduct heat from the humnzan body?
A.  Yes; but being very bad conductors, they convey the heat away so slowJy, that the loss is scarcely perceptible.
Q.  Is the COLD IIEARTII-STONE in Lreality of
the SAME TEMPERATURE as the WvARM CARPET?
A.  Yes; every thing in the room is
really  of one tenmperature; but some
things feel colder than  others, because
they are better conductors.
Q.  How LONG will the hearth-stone feel cold to
thefeet resting on it?
A.  Till the feet and the hearth-stone
are both of the same temperature; and
then the sensation of cold in the hearthstone vJill go off.
Q    X-Why would not the HEARTH-STONE feel
COLD, iwhen it is of the SAME temperature as our
FEET?




160    COMMUNICATION OF HEAT.
A.  Because the heat wolld no longer rush otut of our feet into the hearthstone, in order to produce equilibrium.
Q.  Wh1y does the IEARTII-STONE (when the fire
is lighted) feel HOTTER than the IIEARTTH-rUG?
A. Because the hearth-stone is an
excellent conductor, and parts  with  its
heat very readily; but the woollen hearthrur (being  a bad conductor) parts with
its heat very reluctantly.
Q.  Why does PARTING with HEAT RAPIDLY
make the IIEARTH-STONE feel WARM?
A. Because the rapid influx of heat
raises the temperature of our body so sud.
denly, that we cannot help perceiving the
increase.
Q.  TFAhy does the non-condicting power of the
HEAR.TH-RPUG prevent its feeling so HOT as it really is?
A.  Because it parts with its heat so
slowly and gradually, that we scarcely
perceive its transmission into our feet.
Q.   W'hen we plunge our HIANDS into a basin
of WATER why does it produce a sensation of COLD?
A.  Because -water is a better conductor than air; and, as it draws  off the
heat from our hands more rapidly, itfeels
colder,
Q.  Why does the CONDUCTING pouer of water
make it feel COLDER than AIR? 
A.  Because it abstracts heat from our




WATER.                161
hands so rapidly, that we feel its loss;
but the air abstracts heat so very slowly,
that its gradual loss is hardly perceptible.
Q.  Is woater a GOOD CONDUCTOR of heat?
A.  No; no liquid is a good conductor
of heat; but yet water is a much better
conductor than air.
Q.  Tvhy is WATETR  a BETTER CONDUCTOR Of
heat than AIR?
A.  Because it is less subtile; and the
conducting power of any substance depends upon its solidity, or the closeness
of its particles.
Q.  How do you know that WATER is NOT a
GOOD CONDUCTOR of heat?
A.  Because it may be made to boil at
its sufface, without imparting sufficient
heat to melt ice a quarter of an inch below
the surface.
Q.  IWh/y are NOT LIQUIDS GOOD CONDUCTORS
of heat?
A. Because the heat (which should
be transmitted) produces evaporation, and
flies off in the vapor.
Q.  Why? does a roKiER (resting on a fender)
feel COLDER than the HIEARTH-RnUG, which is further
off thefire?
A.  Because the poker is an excellent
conductor, and draws heat from the hand
much  more rapidly  than  the woollen




162    COMMUNICATION OF HEAT.
hearth-rur, which is a very bad conductor:
though both, therefore, are equally wearm,
the poker seems to be the colder. (See
also p. 173.)
Q.  Why are HOT BPJICKS (wrapped in cloth)
employed in cold weather to ICEEP the FEET WARM?
A.  Because bricks are bad conductors
of heat, and cloth or flannel still iworse:
in consequence of which, a hot brick
(wrapped in flannel) will retailn its heat
a very lonig tine.
Q.  Whiy is a TIN PAN (filled with HOT WATER)
employed as a FOOT-WARMIER?
A.  Because polished tin (being a bad
radiator of heat) ikeeps hot a very long
time; and warms the feet resting upon it.
Q.  TWhat is meant by being a "bad RADIATOR
of heat?"
A. To radiate heat is to throtv off
heat by rays, as the sun; a polished tin
pan does not throw off the heat of boiling
awater firom its surface, but keeps it in.
Q.  TVhy are TIN FOOT-WARMERS covere, with
FLANNEL?
A.  1st —That the polish of the tin
may not be injured:
2dly-Because the flannel (being a
Venj bad conductor) helps to keep the tin
hot longer: and




FOOT-WARMERS-STOVES.    MtY6
3dly-Lest the conducting surface of
the tin should feel painfully h/ot.
Q.   T1hat disadvantage would it be, if the POL.
ISH of the tin were injured?
A.  If the tin foot-warmer were to
lose its p)?lish, it would get cold in a much
shorter timne.
Q.  IfTihy would the tin foot-warmer get COLD
300NER, Zf the POLISH were INJURED?
A. Because polished tin throws off its
heat very slowoly; but dull, scratched,
painted, or dirty tin, throws off its heat
very quickly.
Q.  TIhy are FURNACES and stoves (where
much HEAT is rcquired) built of porozus BRICK?
A.  Because  bricks  are  bad  conductors, and prevent the escape of heat;
in consequence of which, they are employed where great heat is required.
Q.  WVhyJ are FURNACE DOORS, dC., frequently
COVERED wilh a cpaste of CLAY and SAND?
A. Because this paste is a very bad
conductor of heat; and, therefore, prevents the escape of heat fronm the furnace.
Q.  If a stove be placed in the MIDDLE of a room
should it be made of bricks or IRON?
A.  A stove in the middle of a room
should be made of iron; because iron
is an  excellent conductor, and  rapidly
communicates heat to the air around.




164    COMMUNWATION OF HEAT.
Q.  Why does the Bible say, t.Lat God;' giveth
SNOW li/ke XWOOL?"
A.  Because snotw (being a very bad
conductor of heat) protects vegetables
and seeds from the frost and cold.
Q.  How does the nonz-conducting power of SNOW
PROTECT VEGETABLES from the FROST and cold?
A.  It prevents the heat of the earth
fronm  being draon  off  by the cold ail
which rests upon it.
Q.  WAhy are WOOLLENS and Funs used for
CLOTHING in COLD weather?
A. Because they are very bad conductors of heat; and, therefore, prevent
the warmth of the body fronm being drawon
off by the cold air.
Q.  Do not woollens and furs actually IMPART
neat to the body?
A.  No; they merely prevent the heat
of the body from escaping.
Q.  WThere would the heat ESCAPE to, if the
body were NOT wrapped in wool orfur?
A.  The heat of the body would fly
off into the air; for the cold air (coming
in contact with our body) would (gradually drawt away its heat, till it was as
cold as the air itself.
Q.  What then is the PRINCrIPL vTSE of C.OTHLNG in winter-time?
A. lst —To prevent the animal heat
from escaping too freely; and




AIR.                 165
2dly-To protect the body from the
external air (or wind), which  would
carry away its heat too rapidly.
Q.  WTThy are BEASTS COVERED with FUR, HAIR
or WOOL?
A. Because fur, hair and wool, are
very slow  conductors of heat; and  (as
dumb animals cannot be clad, like human
beings) God has given them  a robe of
hair or wool, to keep them  warmn.
Q.   T]Vhy are BIRDS covered withb DOWN or
FEATHERS?
A. Because down and feathers are
very bad conductors of heat; and (as
birds cannot be clad, like human beings)
God has given them  a robe of feathers,
to keep thenm warnm.
Q.   T/thy are WOOL, FUR, HAIR, and FEATHERS$
suh. SLOWV CONDUCTORS of heat?
A.  Because a great quantity of air
lurks entangled between the fibres; and
air is a veryX bad conductor of heat.
The warmest clothing is that which fits the body very
loosely in every part except at the e.xtremilies: Because
more hot air will be confined by a loose garment than by
one which fits the body tightly.
Q.  If AIR be a BAD CONDUCTOR of heat, why
should we not feel as warm WITHOUT clothing, as
when we are wrapped in wool and fur?
A.  Because the air (which is cooler
than our body) is never at rest; and




t66    COMMUNICATION OF HEAT.
every fresh particle of air dravs off a
fresh portion  of heat.
Q.  flow does the ceaseless CHANGE of air tend
to DECREASE the WARMTH of a naked bory?
A.  Thus:-the air (which cases the
body) absorbs as much heat from  it as
it can, while it remains in contact; being
then blown away, it makes rooml for a,fresh coat of air, which absorlbs mnore heat.
Q.  Does the AmR which encases a naked body
become (by contact) as WARM as the BODY itself?
A.  It would do so, if it remained
motiodless; but, as it remains only a very
short time, it absorbs as much heat as it
can in the time, and passes on.
Q.  Why do we feel COLDEr, in, WINDY WEATHiER than in a CALM day?
A. Because the particles of air pass
over us mtore rapidly; and every fresh
particle takes fiom  us some portion of
heat.
Q.  Show the wisdJn of God in making the
AIR a BAD CONDUCTOR.
A.  If air were a good conductor (like
iron and stone) heat would be drawn so
rapidly fron,, our body, that we should be
chilled to death.  Similar evils would be
felt also by all the animal and vegetable
world.
Q.  Does not the bad conductiLng power of air




STALE EGG- FANNING.         167
enable persons to judge whether an EG a b, NEW O0
STALE?
A. Yes; touch the larger end of the
shell with your tongue  if itfeels warm,
the egg is stale; if not, it is new-laid.
Q.  WTAhy will the SHELL of a STALE EGG feel
WARM to the tongue?
A. Because the thick end of an egg
contains a small quantity of air (between
the shell and the white); when the egg
is stale the white shrinks, and the confined air accordingly expands.
Q.  WhAy does the expansion of air (at the end
of an egg) make itfeel WARM to the tongue?
A. Because air is a very bad conductor, and the more air an egg contains,
the less heat will be drawn from the tongue
when it touches the shell.
Q.  WTiLy will a NEW-LAID egg feel COLDER to
the tongue at the thick end than a stale one?
A.  Because it contains more white
and less air; and as the white of an egg
is a better conductor than air, the heat
of the tongue will be drawn off more rapidly, and the egg feel colder.
Q.  Why does FANNING the face in summer
make it COOL?
A. Because the fan puts the air in
motion, and makes it pass more rapidly
over theface; and (as the temperature of




168    COMMUNICATION OF HEAT.
the air is always lower than  that of the
human face) each puff of air carries off
somre portion of its heat.
Q.  Does FANNING make the AIR itself COOLER?
A. No; fanning makes the air hotter
and hotter.
Q.  hlow does FANNING the face increase the
HEAT of the air?
A. By driving the air more rapidly
over the human body, and causing it,
consequently, to absorb more heat.
Q.  If fanning makes the AIR IIOTTER, why can
it make a PERSON feel COOLER?
A. Because it takes the heat outt of
theface, and gives it to the air.
Q.  Thty is BROTII COOLED by BLONrING it?
A.  Because the breath causes a rapid change of air to pass over the broth;
and (as the air is colder than the broth)
it continually absorbs heat from it, and
makes it cooler and cooler.
Q.   Would not tle air absorb heat from the
broth just as well WITHOUT BLOWING?
A.  No; air is a very bad cortactor;
unless, therefore, the change be rapid, the
air nearest the surface of the brothl would
soon become as hot as the broth itself
Q. Would not hot air PART with ilts heat in.
stantly to the CIRCUMJACENT air?
A. No; not instantly. Air is so bad




WIND.               169
a conductor, that it parts with its heat
very slouwly: unless, therefore, the air be
kept in continual mnotion, it would cool
the br'oth very slowvly indeed.
Q.  Why does wIND generally feel COOL?
A.  Because it drives the air more
rapidly over our body; and this rapid
change of air draws off a large quantity
of heat.
Q.  TWhy does AIR ABSORB heat more QUICKLY
by being set i7L MOTION?
A. Because every fresh gust of air
absorbs a Jfesht portion of heat; and the
more rapid the succession of gusts, the
greater will be the quantity of heat absorbed.
Q.  If the AIR were HOTTER than our body
would the WIND feel COOL? 
A. No; the air would feel insufferably hot, it' it were hotter than our body.
Q.  Why would the AIR feel INTENSELY HOT, if?it were WARMER than, our BbDY?
A. Because it would add to the heat
of our body, instead of diminishing it.
Q.  Is tue AIR EVER as HOT as the human
BODY?
A. Not in this country: in the hottest summer's day, the air is at least 10
or 12 degrees cooler than the human body.
Q.  Is the EARTHI a good conductor of heat?
8




170    COMMUNICATION OF HEAT.
A.  No; the earth is a very bad con,
ductor of heat.
Q.   Thy as the EARTH a BAD conductor of heat?
A. Because its particles are not continuous: and the power of condacting
heat depends upon  the continuity of
matter.
Q.  Why is the earth (BELOWr the SURFACE)
WARMER in WVINTER than the surface itself?
A. Because the earth is a bad conductor of heat; and, therefore, (although
the ground be frozen,) the frost never
penetrates more than a fewl inches below
the surface.
Q.  Why is the earth (BELOw  the SURFACE)
COOLER i? SUMMER than the surface itself?
A.  Because the earth is a bad con.
ductor of heat; and, therefore, (although
the surface be scorched with the burning
sun,) the intense heat cannot penetrate
to the roots of the plants and trees.
Q. Show the WISDOM of GOD iln making the
EARTH a BAD CONDUCTOR.
A.  If the heat and cold could pene.
trate the earth (as freely as the heat of
a fire penetrates iron), the springs
would be dried up in summer, and fro.
zen in winter; and all vegetation would
perish.




SHADE COOL.            171
Q.  Why is WATER from a SPRING always
0OOL even in SUMMER?
A.  Because the earth is so bad a conduclor, that the burning rays of the sun
can penetrate only a few inches below
the surface; in consequence of which,
the springs of rwater are not affected by
the heat of summer.
Q.  Why is it COOL under a SHADY tree in a
hot summer's day?
A.  1st-Because the overhanging foliage screens off the rays of the sun:
2dly —As the rays of the sun are warded off, the air (beneath the tree) is not
heated by the reflection of the earth: and
3dly —The leaves of the trees, being
non-conductors, allow  no heat to penetrate themn.
Q.  Why do the LAPLANDERS wear SKINS with
the Firt INWARDS?
A. Because the dry skin prevents the
wind from  penetrating  to their body;
and the air (between the hairs of the fur)
soon becomes heated by the body: in
consequence of which, the Laplander in
his fur is clad in a case of hot air, impervious to the cold and wvind.
Q.  Why does a LINEN SHIRTfeel COLDER than
$ COTTON ONE?
A. Because linen is a much better




172    COMMUNICATION OF1 HEAT.
conductor than  cotton;  and, therefore,
(as soon as it touches the body) it draws
away  the heat more rapidly, and produces a greater sensation of cold.
Q.  W-tRhy is the FACE COOLED by wiping the
temples with afine CAIBmIC HANDKERCHIEF?
A.  Because  the  fine  fibres of the
cambric have a strong capillary attraction
for nmoistutre, and are excellent conductors
of heat: in consequence  of which, the
moisture and heat are abstracted from
theface by the cambric, and a sensation
of coolness produced.
" Capillary attraction," i. e., the attraction of a thtread or
hair. The wick of a candle is wet with grease, because
the melted tallow runs up the cotton from capillary attraction.
Q.  Hrhy would not a COTTON handkerchief do
as well?
A.  Because the coarse fibres of cotton lhave very little capillary attraction,
and  are very bad conductors; in consequence of which, the heat of the face
would be increased (rather than dirnin.
tshed) by the use of a cotton handker.
chief.




AB qSORPTION.           173
CHAPTER XVI.
2.-ABSORPTION OF HEAT.
Q.  What is the difference between CONDUCTING
heat, and ABSORBING heat?
A.  To conduct heat is to transmit it
from one body to another through a conductin,cg  medium. To absorb heat is to
suck it up, as a sponge sucks up water.
Q.  Give me an example.
A.  Black cloth absorbs, but does not
conduct heat; thus, if black cloth be laid
in the sun, it will absorb the rays very
rapidly; but if one end of the black cloth
be made hot, it would not conduct the
heat to the other end.
Q.  Are good CONDUCTORS of heat good ABSORBERS also?
A.  No; every good conductor of heat
is a bad absorber of it; and no good ab.
sorber of heat can be a good conductor
also.
Q.  Is IRON a good ABSORBERP of heat?
A.  No; iron is a good conductor, but
a very bad absorber of heat.
Q.  TV1hy do the FIRE-IRONS (which l,: cpon a
FENDER) remain COLD, although they are before a
goodfire?
A.  Because they are bad absorbcrs of




174    COMMUNICATION OF HEAT.
heat;  in consequence of which, they
remain cold, unless they come in contact
with the stove or fire.
Q.  Why are the FIRE-IRONS intensely HOT,
when they REST AGAINST the STOVE which contains
a good fire?
A. Because they are excellent conductors of heat, and draw  it rapidly fiom the
stove with which they are in contact.
Q.  WHhy does a KETTLE boil faster, when the
bottom and back are COVERED with SOOT?
A. Because the black soot absorbs
heat very quickly from the fire, and the
metal conducts it to the water.
Q.  W;hy will not a NEW KETTLE boil so fast
as an OLD one?
A. Because the bottonm and sides of a
new kettle are clean and bright: but in
an old kettle they are covered iwith soot.
Q.  WIhy will a KETTLE be SLOWER BOILING if
the BOTTOM and BACK are CLEAN and bright?
A.  Because brilght metal does not absorb heat, but reflects it; and (as the
heat is thrown off from the surface of
bright metal by reflection) therefore, a
new kettle takes a lon(er time to boil.
Reflects heat, i. e., throws it off.
Q.  TVhy do we wear WHITE LINEN and a
2;LACK outer DRESS. if we want to be warm?
A.  Because  the  black  outer dress




COLORS.              175
quickly absorbs heat from the sun; and
the vwhite linen (being a bad absorbent)
abstracts no heat from the warm body.
Q.  Why do persons WEAR WHITE dresses in
SUMMER time?
A.  Because white throws  off the heat
of the sun by reflection, and is a very bad
absorbent of heat; in consequence of
which, white dresses never become so
hot fr'0om  the scorching sun  as dark colors do.
Q.  Why do NOT persons wEAR WHITE dresses
in WINTER lime?
A.  Because owhite twill not absorb heat,
like black and other dark colors; and,
therefore, vwhite dresses are not so twarm
as dark ones.
Q.;What COLORns are WAARMESTfOr dresses?
A.  For outside garments black is the
tiwarmest, and then such colors as approach nearest to black, (as dark blue
and green.)   White is the coldest color
for external clothing.
Q.  IVhy are DARKI COLORS (for external wear)
so much WA'.NIER than LIGHT ONES?
A.  Because dark colors absorb heat
from the sun more abundantly than light
ones.
Q.  I-ow can you prove that DARK colors are
WARMER than LIGHT ones?




176     COMMUNICATION OF HEAT.
A. If a piece of black and a piece of
white cloth were laid upon snow, in a
few hours the black cloth twill have nelted
the snow  beneath; whereas, the white
cloth will have produced little or no effect
upon it at all.
N. B. The darker any color is, the warnmer it is, because it is a better absorbent of heat. The order may be
thus arranged:-1.-Black (warmest of all).-2. Violet.3. Indigo.-4. Blue.-5. Green.-6. Red.-7. Yellow: and
8. White (coldest of all).
Q.  Why are BLACK KID GLOVES unpleasantly
HOT for summer wear?
A. 1st-Because black absorbs the
solar heat; and
2dly —Kid will not allow the heat of
our hand to escape through the glove.
Q. Why are LISLE THREAD GLOVES agreeably
COOL for summer wear?
A. ist —Because thread absorbs perspiration: and
2dly-It conducts away the heat of our
hot hands.
Q.  Are Lisle thread gloves ABSORBENTS of
heat?
A.  No; Lisle thread gloves are gen.
erally of a grey or lilac color; and, therefore, do not absorb solar heat.
Q.  Why is a PLATE-WARMER made of UNPAINTED BRIGHT TIN?
A.  Because bright tin reflects the heat




REFLECTOR-HOAR FROST.           177
(which issues from the fire in rays) upon
the meat; and, therefore, greatly assists
the process of roasting.
Reflects the heat, i. e., throws it back upon the meat.
Q.   Why would not the tin REFLECTOR do as
sell, if it were PAINTED?
A.  Because it would then absorb heat,
and not reflect it at all.  A plate-warmer
should never be painted, but should be
kept very clean, bright, and frieefrom  all
scratches.
Q.  Why should a REFLECTOR be kept so very
CLEAN and free from all SCRATCHES?
A. Because if a reflector were spotted,
dull, or scratched, it would absorb heat,
instead of reflecting it; and, consequently,
would be of no use whatsoever as a?-eflector.
Q.  Why does HOAR FROST remain on TOMBSTONES long after it has melted from the GRASS and
G(RAVEL-WALKS of a church-yard?
A.  Because tomb-stones (being white)
will not absorb heat, like the darker grass
and gravel; in consequence of which,
they remain too cold to thaw  the frost
congealed upon their surface.
Q.  If black absorbs heat, why have those who
live in HOT climates BLACK SKINS, and not WHITE
skins, which would not absorb heat at all?
A. Because black will not blister from
8*




178    COMMUNICATION OF HEAT.
the heat of the sun. Although, therefore,
the black skin of the negro absorbs heat
more plentifully than the white skin of a
European; yet the blackness prevents the
sun from blistering or scorching it.
Q.  How is it known that the BLACK color prevents the sun from either BLISTERING or SCORCHING
the skin?
A.  If you put a white glove on one
hand, and  a black glove on the other
(when the sun is burning hot), the hand
with the white glove will be scorched, but
not the other.
Q.  WHICH hand will FEEL the HIOTTER?
A.  The hand with the  black glove
willfeel the hotter, but will not be scorched by the sun; whereas, the hand with
the white glove (though much cooler) will
be severely scorched.
Q.  Why does the BLACK skin of a NEGRO NEVER SCORCH or BLISTER with the hot sun?
A. Because the black color absorbs
the heat-conveys it below the surface of
the skin-and converts it to sensible heat
and perspiration.
Q.  Why does the WHITE EUROPEAN SKIN
BLISTER and SCORCH when exposed to the hot sun?
A.  Because white will not absorb heat:
and, therefore, the hot sun rests on the
surface of the skin, and scorches it.




REFLECTION OF HEAT.          179
Q.  Why has a NEGRO BLACK EYES?
A. Because the black color defends
them  from the strong light of the tropical sun.  If a necro's eyes were  not
black, the sun would scorch thenm, and
every neogro would be blind.
Q.  Wkhy is WATER (in hot weather) KEPT
COOLER in a BRIGHT TIN POT than in an EARTHEN
one?
A.  Because bright metal will not
absorb heat from  the hot air, like an
earthen vessel; in consequence of which,
the water is kept cooler.
Boiling water is also kept hot in bright metal better
than in earthen vessels. See p. 187.
CHAPTER XVII.
3.-REFLECTION OF HEAT.
Q. What is meant by REFLECTING HEAT?
A.  To reflect heat is to throw it back
in rays from the surface of the reflecting
body towards the place whence it came.
Q.  What are the BEST REFLECTORS of heat?
A.  All bright surfaces and liglt  colors.
Q.  Are GOOD ABSOB BES of heat GOOD ]t
FIECTORS also?




180    COMMUNICATION OF HEAT.
A. No; those things which absorb
heat best, reflect heat vworst; and those
which reflect heat worst, absorb it best.
Q.  Why are those things which ABSORB HEAT
unable to REFLECT it?
A.  Because if anything sucks in heat
like a sponge, it cannot throw it off from
its surface; and if anything throiws off
heat from its surfa ce, it cannot driink it in.
Q.  Why are REFLECTORS always made of
LIGHT COLORED and highly POLISIIED METAL?
A.  Because light colored and highly
polished metal makes the best of all reflectors.
Q.  Why do not PLATE-WARIMERS BLISTER and
scorch the WOOD behind?
A.  Because  the  bright  tin  front
throws the heat of the fire back again,
and will not allow it to penetrate to the
wood behind.
Q.  If metal be such an excellent CONDUCTORP of
heat, how can it REFLECT heat, or throw it off?
A. Polished metal is a conductor of
heat, only when that heat is communicated by actual contact: But whenever
heat falls upon bright metal in rays, it is
reflected back again, and the metal remains cool.
Q.  What is meant " by heat falling upon metaJ
IN RAYS," and nwt "' by contact?"




TIN REFLECTORS.           181
A. If a piece of metal were thrust
into a fire, it would be in actual contact
wvith the fire-; but if it were held bfjore a
fire, the heat of the fire would fall upon
it in rays.
Q.  WVhat is the use of the TIN SCREEN or RE.
FLECTOR used in ROASTING?
A.  It throwts the heat of the.fire back
upon the nmeat; and, therefore, both assists the process of roasting, and helps to
keep the kitchen cool.
Q. How does a tin REFLECTOR tend to keep the.KITCHEN COOL?
A. By confining the heat of the fire to
the hearth, and preventing its dispersion
throughout the kitchen.
Q. Why are SHOES HOTTER for being DUSTY 2
A.  Because  dull, dusty shoes will
absorb heat from the sun, earth, and air;
but shoes brightly polished throwl off
the heat of the sun by reflection.
Q.  Why does it always FREEZE on the TOP of
a MOUNTAIN?
A.  1st-Because the air on a mountain is very rarefied; and rarefied air retains more heat in the latent form than
denser air does: and
2dly-Air is heated by the reflection of
the earth, and not by solar rays; therefore
a mountain-top (which is deprived of this
reflection) remains intensely cold.




182    COMIMUNICATION OP HEAT.
CHAPTER XVIII.
4.-RADIATION.
Q.  lrhat is -meant by RADIATION 
A. Radiation means the emission of
rays: thus the sun radiates both light
and heat; that is, it emits rays of light
and heat, in all directions.
Q.  WIHEN is heat RADIATED front one body to
another?
A. When the two bodies are separated
by a non-conducting medium: thus the
sun radiates heat towards the earth, because the air (which is a very bad conductor) comes between.
Q. On WHAT does RADIATION DEPEND?
A.  On the roughness of the radiating
surface: thus, if metal be scratched, its
radiating power is increased; because
the heat has more points to escape from.
Q. Does a FIRE RADIATE heat?
A. Yes; and because burning fuel
emits rays of heat, therefore we feel warm
when we stand before a fire.
Q.  Why does our FACE FEEL uncomnfortablv
HOT when we approach a FIRE?
A. Because the fire radiates heat
upon the face; which (not being covered)
feels the effect immediately.




RADIATION-BL CK LEAD.             183
Q.  W1y does the fire catch the FACE more than
it does the REST of the body?
A. Because the rest of the body is
covered with  clothing; which (being  a
bad conductor of heat) prevents the same
sudden and rapid transmission of heat to
the skin.
Q.  Do those substances which RADIATE heat
ABSORB heat also?
A. Yes. Those substances which
radiate most, also absorb imost heat; and
those which radiate least, also absorb the
least heat.
Q.  Does anything ELSE radiate heat BESIDES
the SUN and FIR-E?
A.  Yes: all things radiate  heat in
some measure, but not equally  vell.
Q.  WHAT things RADIATE heat the NEXT BEST
to the sun and fire?
A.  All dull and dark substances are
good radiators of heat; but all light and
polishcd substances are bad radiators.
Q.   Why should the FLUES (connected with
stoves, Jyc.,) be always BLACKENED with BLACK LEAD?
A, In order that the heat of the flue
may be more readily diffyused throughout
the room.  Black lead radiates heat more
freely than any other known substance.
In heating a room with steam it would be absurd to use
black pipes for conveying the steam, because they would
tend to cool the hot vapor.




184    COMMUNICATION OF HEAT.
Q.  TWhy does a POLISHED METAL TEA POT makA
BETTER TEA than a black earthen one?
A.  Because polished metal (being a
very bad radiator of heat) keeps the water
hot much longer; and the hotter the water is, the better it " draws" the tea.
Q.  Why will not a DULL BLACK TEA-POT make
good tea?
A. Because the heat of the water
flies off so quickly through the dull black
surface of the tea-pot, that the water is
very rapidly cooled, and cannot " draw"
the tea.
Q.  Do not pensioners and aged cottllagers generally prefer the little BLACK EARTIEN TEA-POT to the
bright METAL one?
A.  Yes; because they set it on the
hob " to a, trv;" in which case, the little
black tea-pot will make the best tea.
Q.  Why will a BLACK TEA-POT make better tea
than a bright metal one, if it be set upon the Hor to
DRAW? 
A. Because the black tea-pot will
absorb heat plentifully from the fir e, and
keep the water hot: whereas, a bright
metal tea-pot (set upon the hob) would
throwv off the heat by reflection.
Q.  Then sometimes a BLACK EARTIIEN tea-pot
is the best, and sometimes a bright metal one?
A. Yes; when a tea-pot is set on/the




SAUCEPAN-KETTLE.           185
hob "to draw," black earth is the best,
because it absorbs heat: But, when a
tea-pot is not set on the hob, bright metal is the best; because it radiates heat
very slowly, and therefore keeps the 7water
hot.
Q.  Why does a SAUCEPAN which has been USED
boil in a shorter time than a NEW ONE?
A. Because the bottom and back are
covered swith soot; and black soot rapidly
absorbs the heat of the glowing coals.
Q.  Why should the FRONT and LID of a SAUCE
PAN be clean and BRIGHT?
A. Because they cannot absorb heat,
as they do not come in contact with the
fire; and (being bright) they will not
suffer the heat to escape by radiation.
Q.  In what state should a SAUCEPAN be in order that it may BOIL QUICKLY 2
A. All those parts which come in
contact with the fire, should be covered
with soot, in order to absorb heat; but
all the rest of the saucepan should be as
bright as possible, to prevent the escapp.~
of heat by radiation.
Q.  Why should NOT the BOTTOHM and BACK of
a kettle be CLEANED and polished?
A.  Because, they come in contacit with
the fire, and (while they are covered wvith



186    COMMUNICATION OF HEAT.
black soot) absorb heat freely from the
burning coals.
Q    Why should the FRONT and TOP of a kettle
be CLEAN and well polished?
A. Because polished metal twill not
radiate heat; and, therefore, (while the
front and top of the kettle are well polished) the heat is kept in, and not suffered
to escape by radiation.
Q.  Why is the BOTTOM of a KETTLE nearly
COLD when the WATER is BOILING HOT?
A. Because black soot is a very bad
conductor of heat; and, therefore, the heat
of the boiling water is some time before
it gets through the soot which adheres to
the bottom of the kettle.
Q.  Why is the LID of a KETTLE intensely HOT
when the uwater boils?
A.  Because the bright metal lid is an
admrirable conductor; and, therefore, the
heat from the boiling twater pours into our
hand the moment we touch it.
Q.  Show the benefit of SMOKE in COOKING?
A. The carbon of' the fuel (which
flies off in smoke) naturally blackens all
culinary vessels set upon the fire to boi;,
and thus renders themt fit for use.
"Culinary vessels" are vessels used in kitchens for
cooking, as saucepans, boilers, kettles, &c., (from the LatJi
word " Culina," a kitchen.L




SMOKE-BRIGHT METAL;            187
Q.  tHow does SMOKE make culinary vessels FIT
for USE?
A.  By absorbing heat.  If it were
not for the smoke (which gathers round
a kettle or saucepan) heat 2would not be
absor'bed, and the process of boiling would
be greatly retarded.
Q.   Why is boiling water KEPT HOT in a
BRIGHT METAL pot better than in an earthen vessel?
A. Because bright metal (being a
bad radiator) will not throew offfrom  its
surface the heat of the boiling water.
Q.  Would a metal pot serve to keep water hot
if it were DULL and DIRTY?
A.  No.  It is the bright polish of the
metal which makes it a bad radiator: if
it were dull, scratched, or dirty, the heat
would escape very rapidly.
Water in hot weather is also kept cooler in bright metal
than in dull or earthen vessels. See p. 179.
Q.  Why are DINNER-COVERS made of BRIGHT
TIN or SILVER?
A. Because light-colored and highlypolished mnetal is a very bad radiator of
heat; and, therefore, bright tin or silver
will not allow the heat of the cooked food
to escape through the cover by radiation.
Q.  Why should a MEAT-COVER be very brightly
POLISHED?
A. To prevent the heat of the food




188    COMMUNICATION OF HEAL.
from escaping by radiation.  If a meatcover be dull or scratched, it will absorb
heat fr'om  the food beqneath; and (instead
of keeping it hot) make it cold.
Q.  Why should a SILVER MEAT-COVER he
PLAIN and not CHASED?
A. Because a chased meat-cover
would absolrb heat frSor  the food; and
(instead of keeplin  it hot) make it cold.
Q.  Wfhat is DEW?
A.  Dew is the vapor of the air condensed by coming in contact with bodies
colder thanl itseyf
Q.  Wtchy is the GsrOUND sometimes COVERED
with DEW? 
A.  Because the surface of the earth
(at sun-set) is made so very cold by radiation, that the warm vapor of the air is
chilled by contact, and condensed into
dew.
Q.  Wxhy is the EARTH made colder than the
AIR after the suit has set?
A.  Because the  earth radiates heat
very freely, but the air does not; in consequence of which, the earth is often 5
or 10 decrees colder than the air (after
sun-set); although it was much ivariner
than the air, during the whole day.
Q.  WAy is the EARTH WhRMER than  ie AIR
during the d-y?




DEW.               189
A. Because the earth absorbs solar
heat very freely, but the air does not; in
consequence of which,it is often many degrees warmer than the air, during the day.
Q.  IsVhy is the surface of the GROUND COLDER
in a FINE clear NIGHT than in a CLOUDY one?
A. Because, on a fine, clear star-light
night, heat radiatesfrom the earthfreely,
and is lost in open space: but on a dull
night, the clouds arrest the process of radiation.
Q.  Why is DEW deposited only on a FINE, clear
NIGHT?
A. Because the surface of the ground
radiates heat most freely on a fine niglht;
and (being cooled down by this loss of
heat) chills the vapor of the air into dew.
Q.  Why is there NO DEW on a dull, CLOUDY
NIGHT?
A. Because the clouds arrest the
radiation of heatfrom the!arth; and (as
the heat cannot freely escape) the surface is not sufficiently cooled down to
chill the vapor of the air into dew.
Q. Why is a CLOUDY NIGHT WARMER than a
FINE one?
A. Because the clouds prevent the
radiation of heatfromr the earth; in consequence of which, the surface of the
earth remains warmer.




190    COMMUNICATION OF HEAT.
Q.  Why is DEW most ABUNDANT in situations
iost EXPOSED?
A. Because the radiation of heat is
not arrested by houses, trees, hedges, or
any other thing.
Q.  WThy is there scarcely any DEW under a
shady TREE?
A.  lst-Because the shady head of
a tree arrests the radiation of heat from
the earth: and
2dly-A  leafy tree radiates some of
its own heat towards the earth; in consequence of which, the ground underneath
a tree is not sufficiently cooled down to
chill the vapor of the air into dew.
Q.  WThy is there never much DEw at the foot
of WALLS and HEDGES?
A. 1st-Because they act as screens,
to arrest the radiation of heat fi'orm the
earth: and
2dly-The'  themselves radiate sonze
portion of heat towards the earth; in
consequence of which, the ground at the
foot of walls and hedges is not sufficiently
cooled down, to chill the vapor of the air
into dew.
Q.  WVhy is there little or No DEW beneath a
FLOWER-AWNING, although that awning be open on
ll four sides?
A.  1st-Because the awning arrests




FROST-SNOW.             191
the radiation of heat from  the ground
beneath: and
2dly-It radiates some of its own heat
downwards; in consequence of which,
the ground beneath an awning is not
sufficiently cooled down, to chill the vapor of air into dew.
Q.  How can a thin covering of BASS or even
MUSLIN protect trees from FRosT?
A. Because any covering prevents
the radiation of heat from the tree; and
if trees are not cooled down by radiation
the vapor of the air will not befrozen, as
it comes in contact with them.
Bass pronounce bas-a kind of matting used by gardeners.
Q.  Why is the BASS or CANVASS itself (whicA
covers the tree) always DRENCHED swith DEW?
A.  Because it radiates heat both upwards and downwards; in consequence
of which, it is so cooled down that it readily chills the vapor of the air into dew.
Q.  Why does SNOW (at thefoot of a HEDGE 0F
WALL) melt sooner than that in an open field?
A. Because the hedge or wall radiates heat into the snow  beneath, which
melts it.
Q. Why is there NO DEW after a WINDY NIGHT?
A.  1st-Because the wind evaporatea




192    COMMUNICATION OF HEAT.
the zmoistzure, as fast as it is deposited.
and
2dly-It disturbs the radiation of heat;
and thus diminishes the deposition of
dev.
Q.  WInhy are VALLEYS and HOLLOWS often
thickl.y covered with DEW, although they are sheltered?
A. Because the surrounding hills
prevent the repose of air from being disturbed; but do not overhang and screen
the valleys sufficiently to arrest their radiation.
Q.  Why does DEW fall more ABUNDANTLY on
SOME TILINGS than, on OTHERS?
A. Because some things radiate heat
more frJeely than others; and, therefore,
become mnuch cooler in the nilght.
Q.   T'Why are things which rADIATE HEAL
MOST FREELY always the most THICKLY COVERED
with DEW?
A. Becaulse the vapor of the air is
chilled into dew, the moment it comes in
contact with them.
Q.  WHAT kind of things RADIATE HEAT most
FREELY?
A. Grass., wood, and the leaves of
plants, radiate heat very freely: but polished metal, smooth stones, and woollen
cloth, part with their heat very:ardily.
Q.  Ito the leaves of AL", plants s adiate heai
EQUALLY WELL?




VEGETABLES.             193
A. No. Rough,?woolly leaves (like
chose of a holly-hock) radiate heat much
more'freely than the hard, smooth, polished
leaves of a common laurel.
Q.  Show the WISDOM of GoD in making grass,
the leaves of trees, and ALL VEGETABLES, EXCELLENT
RADIATORS of heat?
A.  As vegetables require much nmoisture, and would often perish without a
plentiful deposit of dew, God  wisely
made them to radiate heat freely, so as to
chill the vapor (which touches them) into dew.
Q.   Will polished METAL, smooth STONES, and
woollen CLOTH, readily collect DEW?
A. No. While grass and the leaves
of plants are completely drenched with dletv
a piece of polished metal, or of woollen cloth
(lying on the same spot), will be almost
dry.
Q. IWthy would POLISHED METAL and WOOLLEN CLOTH be DRY, while grass and leaves are
drenched with DEW?
A. Because the polished metal and
woollen cloth part with their heat so slowly, that the vapor of the air is not chilled
into dew as it passes over them.
Q.  Why is a GRAVEL WALK almost DRY, When
a grass plat is covered thick with DEW?
A. Because grass is a good radiator
9




194    COMMUNICATION OF HEAT.
and throws off its heat very freely; but
gravel is a very bad radiator, and parts
with its heat very slowly.
Q.  Is that the reason why GRASS is SATURATED
with DEW, and the GRAVEL is NOT?
A.  Yes.  When the vapor of warm
air comes in contact with the cold grass,
it is instantly chilled into dew; but it is
not so fr'eely condensed as it passes ower
gravel, because gravel is not so cold as
the grass.
Q.  Wlhy does DEW rarely fall upon hard
ROCKs and BARREN lands?
A. Because rocks and barren lands
are so conmpact and hard, that they can
neither absorb nor radiate much heat;
and (as their temperature varies but very
little) very little dew distils upon them.
Q.  Why does DEW fall more abundantly 0n
CULTIVATED soils than on BARREN lands?
A.  Because cultivated soils  (being
loose and porous) very freely radiate by
night the heat which they absorbed by
day; in consequence of which, they are
much cooled down, and plentifully condense the vapor of the passing air into
dew.
Q.  Show the WISDOM of GOD in this arrange.
ment.
A.  Every plant and inch of land,




GIDEON'S MIRACLE.           195
which needs the  moisture  of dew, is
adapted to collect it; but not a sincgle
drop is woasted where its refreshing moisture is not required,
Q.  Show the advantae to us in having polished METAL and woollen CLOTH BAD RADIATORS of
heat.
A.  If polished metal collected dew as
easily as grass, it could nvver be kep]t dry
and firee froom  rust.  Again, if woollen
garments collected dew as readily as the
leaves of trees, we should be (flea soatking weet, and subject to constant colds.
Q.  Show how this afforls a beautiful illtstration of GIDEON'S MIRACLE, recorded in the book of
uclges, vi. 37, 38.
A.  The fleece of wool (which is a very
bad radiator of heat) was soaking wvet
with dew, when  the grass (which is a
most excellent radiator) was quite dry.
Q.  TlTas not this CONTRARY to the l4wws of
NATURE?
A.  Yes; and was, therefore, a plain
demonstration of the povwer of God, who
could thus change the very nlature of
things at his will.
Q. ]Why do our CLOTHES FEEL DAMP, after
walking in a fine evening in SPRING or AUTUMN?
A.  Because the vapor (condensed by
the cold earth) lights upon themn like dew.




196    COMMUNICATION OF HEAT.
Q   Wh/ are WINDnows  often covered with tfi/cA
MIST, and the frames wet with standingr WATER?
A.  Because the temperature of the
external air always falls at sunset, and
chills the wvindowv-glass with which  it
comes in contact.
Q. fiow does this account for the MIST and WATER on a WINDOW?
A.  As the warm vapor of the room
touches the cold glass it is chilled and condensed into nmist; and the mist (collecting inlto drops) rolls down the windowframe in little streams of water.
Q.  Does the GLASS of a window COOL down
more RAPIDLY than the AIR of the room itsef?
A.  Yes;  because  the  air is  kept
zwarnm  by fires, and by the animal heat
of the people in the room; in consequence
of which, the air of a room suffers very
little diminution of heat from the setting
of the sun.
Q.  W'hence arises the VAPOR of a ROOM?
A.  1st-The very air of the room
contains vapor:
2dly-The breath and insensible rprspiration  of the inmates increase this
vapor: and
3dly —Hot dinners, the steamn of tean
and so on, increase it still more.




MIST-VAPOR.              197
Q.  What is meant by " the INSENSIBLE PERI
BPIRATIGN?"
A.  From  every part of the human
body, an insensible and invisible perspiration issues all night and day; not only
in the hot weather of sunmtnter, but also
in the coldest day of wvinter.
Q.  f' lthe perspiration be both INSENSIBLE and
INVISIBLE, how is it KNOWN that there is any such
perspiration?
A.  If you put your naked arm  into a
clean, dry glass tube, the perspiration will
condense on the glass like mist.
Q.  /Tzy are CARRIAGE WINDOWS very SOON
covered with thick MIST?
A. Because the warm vapor of the
carriage is condensed by the cold glass,
and covers it with a thick mist.
Q.  WnYI is the glass window COLD enough to
condense the vapor of the carriage?
A. Because the inside of a carriage
is much iwarmer than the outside; and
the glass window is made cold by contact with the external air.
Q.  WHNERE tdoes the WARMA vapor of the carriage come from?
A. The warm breath and insensible
perspiration of the persons riding, load
the air of the carriage with warm vapor,
Q.  TWhat is the cause of the pretty FrIOST
WORK, seen on bed-room WINDOWS in whiter time?




198    COMMUNICATION OF HEAT.
A.  The breath and insensible persp.
ration of the sleeper (coming in contact
with the ice-cold window) arefrozen by
the cold glass, and form those beautiful
appearances seen in our bed-rooms on a
winter mlorning.
Q.  lWhy is the GLASS of a window colder than
the WALLS of a room?
A.  Because glass is so excellent a ra
diator, that it parts with its heat more
rapidly than the walls do.
Q.  Why is a TUMBLER of cold WATER made
quite DULL with mist, when brought into a rooms
FULL of PEOPLE?
A.  Because the hot vapor of the room
is condensed upon the cold tumbler, with
which it comes in contact; and changes
its invisible and gaseous form into that
of a thick mist.
Q.  W/jhy is a GLASS made quite DULL by laying a HOT HAND upon io?
A.  Because the insensibleperspiration
of the hot hand is condecnseal upon the cold
glass, and made perceptible.
Q.'ihy are WINE-GLASSES made quite DULL,
when they are brought into a r'oom FULL of COMPANY?
A. Because the hot vapor of the
r'oom (coming in contact with the cold
wine-glasses) is condensed upon them,
and covers them with vapor, like dew,




WINE GLASS-WALLS.           195
Q.  TVhy does this misty appearance co OFF,
after a little time?
A. Because the glass becomes of the
same ternperature as the air of the room;
and will no long'er c/till the vapor which
touches it, and condense it into mist.
Q.  Thy is a WINE GLASS (which has been
brought out of a CELLAR into the AIR) covered with
a thick MIST in summer-time?
A. Because the vapor of the hot air
is condensed into a thick mist, by contact
with the cold glass.
Q.  Why does BREATHING on a GLASS make it
quite DULL?
A.  Because tile hot breath is condensed by the cold glass; and therefore
covers it with a thick mist.
Q.   VAthy are the WALLS of a house covered
with WET in a sudden THAW?
A.  Because the walls (being thick)
cannot change their templerature so fast
as the air; in consequence of which, they
retain their cold after the thaw has set in.
Q. HIow does " RETAINING their COLD" account
for their being so WET?
A. As the vapor of the warm air
touches the cold walls, it is chilled and
condensed into water; which either sticks
to the walls or trickles down in little
streams.




200    COMMUNICATION OF HEAT.
Q.  Why does a thick WELL-BUILT HOUTSE COrm
tract mowre DAMP of this kind than an ORDINArsn
one?
A.  Because  the  walls  are  much
thicker; and (if the frost has penetrated
far into the bricks) they will be some
time before they are reduced to the same
tenmperature as the air.
Q.  TVhy are BALUSTERS, oC., DA3MP after a
THAW?
A.  Because they are made of some
very  close-grained   varnished   wood,
which cannot chancge its teniperatw'me so
fast as the air.
Balusters-corruptly called banisters.
Q.  How does Tils account for the BALUSTERS
being DAMP? 
A.  The vapor of the warm  air (cominc in contact with the cold balusters) is
chilled and condensed into twater upon
them.
Q.  Why is our BREATH VISIBLE in WINTER,
and NOT i3n SUMMER?
A.  Because  the  intense  cold condenses our breath  into  visible tvapor;
but in summer the air is not cold enough
to do so..
Q.  Why are our HAIR and the BRIM of our
tIAT often covered with, little drops of pearly DEW
sn winter-time?
A. Because our breath is condens.od




WINDS-MOISTNESS.            201
as soon as it comes in contact with our
cold hair or hat, and hangs there in little
dew-drops.
Q.  Wthy does the STEAM of a RAILWAY BOILER
often I our down, like fine rain, when the steam is
"let off?"
A. Because in cold weather the
steam  fiom the chimney is condensed by
the chill air and falls like fine rain.
Q.  TWVhy is there LESS DENW when the WIND is
WESTERLY, than whenL the wind is EASTERLY? 
A.  Because westerly winds cross the
continent, and, (as they pass over land)
are dry and arid: But easterly winds
cross the Atlantic Ocean, and (as they
pass over water) are mnoist and full of
vap)or.
Q.  How does the DRYNESS of a westerly wind
PREVENT DEW-FALLS?
A.  As westerly winds are very dry,
they imbibe the moisture of the air; in
consequence of which, there is very little
left to be condensed into dew.
Q.  Hlow does the MOISTNESS of an eastern wind
PROMOTE deuw-falls?
A. As easterly winds are saturated
with vapor, they require very little reduction of heat to cause a copious deposition of dew.
Q.  When is DEW most COPIOUSLY distilled?
9'




202    COMMUNICATION OF HEAT.
A.  After a hot day in summer oi
autumn, especially if the iwind be easterly.
Q.  WVhy is DEw distilled most COPIOUSLY af.
ter a HOT day?
A.  Because the surface of the hot
earth radiates heat very freely at sunset,
and (being made much colder than the
air) chills the passing vapor and condenses it into dew.
Q.  Does not xAIR radiate heat, as well as the
EARTH and its vacrious plants?
A.  No.'The air never radiates heat;
nor is the air made hot by the rays of
the sun.
Q.  How is the AIR, made HOT or COLD?
A.  By convection of hot or cold currents.
Q.  Explain this.
A.  The air which has been heated by
the surface of the earth ascends, warmin  thle  air throughl wich it passes.
Other air (bein( warmed in a similar
way) also ascends, carrying heat; and
this is repeated, till all the air is made hot.
Q.  -liou, is the AIR made COLD?
A.  lThe air resting on the earth is
made cold by contact: this cold air nmakes
the air above it cold; and cold currents
(or winds) shake the tvhole tojrether, till
all becomes of one temperature.




MOONLIGHT-HONEY-DEW.    203
Q.  Why is MEAT very subject to TAINT On a
IOONLIGHT night?
A. Because it radiates heat very freely
in a bright moonli-lght night; in consequence of which, it is soon covered with
rlew, which produces rapid decompjosition.
Q.  HIow do MOONLIGHT nights conduce to the
rapid GROWXTH of PLANTS?
A. Radiation is carried on very
rapidly on bright moonlight nights; in
consequence of which, dew is very plentifully deposited on young plants, which
conduces much to their growth and vigor.
Q.  Whv is evening DEW INJURIOUS tO HEALTH?
A. Because it is always laden with
noxious exhalations from the earth; especially iln marshy countries.
Q. Is HONEY-DEW a similar thing to DEW f
A. No. Honey-dew is a sweet liquid
shed by a very small insect (called the
a'phis) and deposited in autumn on the
under surface of favorite leaves.
Frequently also on Lime Trees, in the Spring.
Q. Does HONEY-DEW INJURE leaves, or do them
good?
A.  It injures them very much, by filling the pores with a thick, clammy liquid;
in consequence of which, the leaf can




204    kOMMUNICATION OF HEAT.
neither transpire nor absorb its nledful
food.
Q. WMhat EFFECT has honey-dew upon thd
APPEARANCE of a leaf?
A. After a little time, the leaf (being
sntot.htered and starvud) begins to turn a
dinzgy yellowo.
Q.  Are not ANTS very FOND of HONEY-DEW?
A.  Yes; and crawl up the loftiest
trees in order to obtain it.
Q.  WIhat is the cause of MIST (or earth-fog)?
A.  If the night  has been very calnt,
the radiation of heat from the earth has
been very abundant; in consequence of
which, the air (resting on the earth) has
been  chilled, and  its vapor condensed
into a thick mist.
Q.  Why does not the MIST become DEW?
A.  Because the chill of the air is so
rapid, that vapor is condensed faster
than it can be deposited; and (covering
the earth in a rmist) prevents any further
radiation of heat from the earth.
Q.  When the earth can no longer RADIATE
heat upwards, does it continue to CONDENSE the vapor
of the air?
A.  No; the air (in contact with the
earth) becomes about equal in tempera.
ture with the surface of the earth itself
for which reason, the mist is not con



DEW-DROPS.             205
densed into dew, but remains floating
above the earth as a thick cloud.
Q.  This MIST seems to RISE UIGIIER and
HIGHER: and yet remains quite as dense below as at
first. Explain the cause of this.
A.  l'he air resting on the earth is
first chilled, and chills the air resting on
it; the air which touches this netw layer
of mist being also condensed, layer is
added to layer: And thus the mist seems
to be rising, when (in fact) it is only
deepening.
Q.  Why do MIST and DEW VANISH, as the SUN
rises?
A. Because the air becomes warmer
at sun-rise, and absorbs the vapor.
Q.  Why is a DEW-DROP ROUND?
A. Because every part of it is equally
balanced; and, therefore, there is no
cause why one part of the drop should
be further from the centre than anothlr.
Q.  Why is the DEW-DROP (on a broad leaf)
sometimes FLATTENED?
A.  Because two or more drops of
dew roll together, and make one large
Rpheroid (or flattened drop).
Q.  Why will DEW-DROPS ROLL ABOUT CABBAGE-PLANTS, POPPIES, 4Cc., without wetting the surface?
A. Because the leaves of cabbages




206    COMMUNICATION OF HEAT.
and poppies are covered with a very fin
tvaxen powder, over whlich the dew-drop
rolls without wettinr the surface, as a
drop of rain would over dust.
Q.  Why does not a d-rop of RAIN WET the
DUST over which it rolls?
A. Because dust has no affinity for
water, and, therefore, repels it.
Q.  Why does not the DEW-DROP WET the row
DER of the CABBAGE-PLANT?
A. Because the fine powder which
covers the cabbag'e-leaves has no affniti,
fogrwater, and, therefore, repels it.
Q    Why will DEW-DROPS ROLL over a ROSE,
_c., without wetting the petals?
A.  Because the leaves of a rose contain an essential oil, which has no affinity
for water, and, therefore, repels it.
Q.  W'y can SWANS and DUCKS dive under
water WITHOUT being WETTED?
A. Because their feathers are covered with an oily secretion, which has no
affinity for water, and, therefore, repels it.
Q.  What is the cause of MIST?
A. Currents of air from the water
coming in contact with colder land currents,
Q.  Why are the currents of air from the LANI
COLDER than those blowing over WATER? 




AIR AND WATER.            207
A.  Because the earth radiates heat
after sun-set more freely than water;
consequently the air which comes in contact with  the land is more cold than
that which comes in contact with water.
For other questions respecting land and sea breezes see
Chapter XXIV.
Q.  W7by is not the AIr, which passes over
WATER SO COOL as that which passes over LAND?
A.  Because  water  does  not cool
down at. suh-set so fast as land does;
and, therefore, the air in contact with it
remains wartmer.
Q.  Why does not WATER cool down so fast as
LAND?
A.  1st-Because the surface of water
is perpetually chagtnng; and, as fast as
one surface is made cold, another is presented: and
2dly-The  moment water is made
cold it sinkls, and warnecr portions of water rise to occupy its place: therefore,
before the surface of water is cooled, the
whole voltne rmust be made cold: which
is not the case with land.
Q.  JThat is the cause of a "pea-soup" LONDON FOG?
A. Tlhese fogs (which occur generally in the winter time) are occasioned
thus:-Some current of air (beinr sud



208    COMMUNICATION OF HEAT.
denly cooled) descends into  the wcarmn
strects, forcin( back the smoke in a mass
towards the earth.
Q.  Wchy are there not FOGS EVERY night?
A.  Because the air will always hold
in solution a certain quantity of vapor,
(which varies accordingr to its temlperatlre:) and, when. the air is not saturated,
it may be cooled without parting with
its vapor.
Q.  ITVhen do FOGS occur at night?
A.  When the air is saturated with
vapor during the day.  When this is the
case, it deposits some of its superabundant moisture in the form of dew or fog
as soon as its capacity for holdin( vapor
is lessened by the cold night.
Q.  HWhy is there very OFTEN a fog over
mi Isa.S and inivLt:s, at night-time?
A. Because the air of marshes is
almost always near saturation; and,
therefore, the least depression of tenmperature will compel it to relinquish some
of its moisture in the form  of dew  or
fog.
Q.  What is the DIFFERENCE between DEwv ana
aAIN?
A.  In dleo, the condensation is made
near the earth's sutface.




MIST ANI) FOG.            209
In rain, the drops fall from  a considerable height.
Q.  What is the CAUSE of both dew and rain?
A.  Cold condensinrg the vapor of the
air when near the point of sataratign.
Q.  I'Vhy do MIST anld FOG VANISI at sun-rise?
A.  Because the condensed particles
are again chatned into invisible vapor by
the heat of the sun.
Q.  What is the difference between a MIST and a
FOG?
A.  MIST is generally applied to vapors condensed on rmarshes, rivers, and
lakes.
FoG is generally applied to vapors
condensed on land; especially if those
vapors are laden with smoke.
Q.  W'hat is the reason why condensed vapor
sometimes forms into CLOUDS, and sometimes into
FOG?
A. If the surface of the EARTH is
hotter than  the air, the vapor of the
earth is chilled by the cold air, and becomes FOG: But if the AIR is hotter than
the earth, the vapor rises throagh the air,
and becomes CLOUD..Q. If cold air produces FOG, why is it not
foggy on a FP1OSTY MORNING? 
A.  Ist-Because less vapor is f)rmed
on aftrosty day: and




210    COMMUNICATION OF HEAT.
2dly-The vapor is frozen upon the
ground, before it can rise from the earth,
and becornes HOAR-FROST.
Q.  Why are FOGS more general in AUTUMN
than in spring?
A.  tst-Because the air in spring is
generally much drier than it is in autumn;
in consequence of which, it is not so near
the point of saturation: and
2dly-The earth in spring is not so
hot as it is in autumn; in consequence
of which, its vapor is not chilled into fog
as it issues into the air.
Q.  W'hy are FOGS snore common in VALLEYS
than on HILLS?
A. 1st - Because valleys contain
more rnoisture than hills: and
2dly-They are not exposed to suffim
cient wind to dissipate the vapor.
Q. How does WIND dissipate FOGS?
A.  Either by blowoing them  away;
or else by dissolving them into vapor
again.
Q.  What is HOAR-FROST?
A. There are two sorts o' hoar-frost;
1.-FROZEN DEW: and 2. —T  tOZEN FOG.
Q.  What is the cause of the GROUND HOARFROST, or? fozen DEW?
A.  Very rapid radiation of heat from
the earth; in consequence of which, the




HOAR-FROST.            211
rT fiace is so cooled doiwn that it freezes
the dezo condensed upon it.
Q.  tVhy is HOAR-FROST seen only after a very
CLEAR NIGHT'?
A. Because the earth will not have
thrown off heat enough by radiation to
freeze the vapor condensed upon its surface, unless the night has been very clear
indeed.
Q.  Why does HOAR-FROST very ojten cover
the GROUND and TREES, when the water of rivers is
not frozen?
A. Because it is not the effect of cold
in the air, but cold on the surface of the
earth (produced by excessive radiation),
which freezes the dewv condensed upon it.
Q.  Why is the HIOAR-FROST Upon GRASS and
VEGETABLES much thicker than that upon lofty
TREES?
A. Because the air (resting on the
suiface of the ground) is much colder
after sun-set than the air higher up; in
consequence of which, more vapor is
condensed andfrozen there.
Q.  WIly is the AIR (resting on the surface of
the EARTH) colder than that in the HIGHER regions?
A.  Because the earth radiates more
heat than the leaves of lofty trees; and,
therefore, more rapidly condenses and
freezes the vapor of the air.




212    COMMUNICATION OF HEAT.
Q.  Why are EVERGREENS often FROST-DITThL
when lofty trees are NOT?
A. Because they do not rise far above
the surface of the earth; and (as the air
conti0guous to the earth is made colder by
radiation than that in the hiogher regions),
therefore, the lot evergreen is often fr3ostbitten, when the lofty tree is uniinjured.
Q.  Why is there little or NO HOARI-FROST Under SHRUBS and shady TREES?
A.  1st-Because the leafy top arrests
the process of radiation from the earth:
2dly —Shrubs and trees radiate heat
towards the earth: and, therefore, the
ground beneath is never cold enough to
congeal the little dew which rests upon it.
Q.  W'hat is the cause of that HOAR-FROST
which arises from FROZEN FOG?
A. The thick fog which invested the
earth durinog the night (being7 condensed
by the coldfr7ost of early morning), is co.ngealed upon every object with wllich it
comes in contact.




CONVECTION'.           213
CHAPTER XIX.
5.-CONVECTION.
Q.  Tlrhat is meant by the CONVECTION of
1IEAT?
A.  Heat communicated  by  being
carried to another thing or place; as the
hot water resting on the bottom of a kettle carries heat to the water through
which it ascends.  (See p. 226.)
Q.  Are LIQUIDS good CONDUCTORS of heat?
A.  No; liquids are bad conductors;
and are, therefore, made hot by convection.
Q. W/hy are LIQUIDS BAD CONDUCTORS of
heat?
A.  Because heat converts a liquid into
steann; and flies off with the vapor instead of being conducted through  the
liquid.
Q.  Explain how WATER is made HOT.
A.  The water nearest the fire is first
heated, and (being heated) rises to the
top; while its place is supplied by colder
portions, which are heated in turn, till
all the water is boiling hot.
Q.  Why is WATER in such continual FERMENT2
when it is BOILING?
A. This commotion is mainly produ



214     COMMUNICATION OF HEAT.
ced by the ascending and descending currents of hot and cold water.
The escape of steam from the water contributes also to
increase this agitation.
Q.  irow do these two currents PASS each other.?
A.  The hot ascending current rises up
through the centre of the mass of water;
while the cold descending currents pass
down by the metal sides of the kettle.
For other questions on the subject of boiling water,
see from page 109 to 115.
Q.   Why is IIEAT applied to the BOTTOm, and
7ot to the top of a KETTLE?
A.  Because the heated water always
ascends to the surwface, heating the water
through which it passes; if, therefore,
heat were applied to the top of a vessel,
the water below the surface would never
be heated.
Q.  As the lower part of a GRATE is made REDHOT by the fire ABOVE, why would not the WATER
boil, if fire were applied to the TOP of a kettle?
A. The iron of a grate is an excellent
conductor; if, therefore, one part be heated, the heat is conducted to every other
part: But water is a very bad conductor,
and will not diffuse heat in a similar way.
Q.  Prove that WATER is a BAD CONDUCTOR of
heat.
A.  When a blacksmith immerses his
red-hot iron in a tank of water, the water




BOILING WATER-SOUP.          215
which surrounds the iron is made boiling
hot, while that below the sutrfcc e remains
quite cold.
Q. if you wish to COOL LIQUIDS, where should
the cold be applied?
A.  To the top of the liquid; because
the cold portions will always descend, and
allow the warmer parts to come in contact with the cooling substance.
Q.  Does BOILING water get hotter by being
KEPT on the FIRE?
A.  No:  not if the steam be suffered
to escape.
Q.  WHY does not boiling H1er get HOTTER,
if the steam be suffered to ESCAPE?
A.  Because the water is converted
into steam as fast as it boils; and the
steam  carries away the additional heat.
Q.  Why does soup keep HOT longer tha;, boil.
ing water?
A. Because the grease and various ingredients floating in the soup, oppose the
ascending motion of the hot particles,
and prevent their rising so freely to the
surface.
Q.  If you* wanted to keep WATER HOT for a
long time, how could it be done?
A.  By adding a little starch or flour
to the water.
Q. Why would a little STAROCIH added to boil.
ing water, serve to keep it HOT?




216    COMMUNICATION OF HEAT.
A.  Because  it would  oppose the
ascending motion of the hot particles of
water, and prevent their rising so freely
to the suLface.
Q.  WAIy do THICK MILK, RICE MILK, I hC., re
mainl HOT loinger than water?
A.  Because the ascending motion of
the hot particles is opposed by the flour
or rice, and cannot so quickly reach the
surface.
Q.  Is STEAM visible or INViSIBLE?
A.  Steam  is is iisible; but when it
comrles in contact with  the air (being
condensed into small drops) it instantly
becomes visible.
Q.  flow do you know that STEAM' is INVISIBLE 
A.  If you look at the spout of a boilb
ing kettle, you will find that the steam
(which issues firomn the spout) is always
invisible for about half ant incA; after
whllich it becomes visible.
Q.  WiHY is tile steam INVISIBLE for HALF AN
INCH?
A.  Because  the  air is not able to
condense it, as it first issues from  the
spout; but when it spreads and comes in
contact with a larger volume of air, the
invsisible steam, is readily condensed into
visible drops.
Q.  WnY do STEAM-ENGINES sometimes BsuRs1 




HEATED AIR.              217
A.  Because:steam  is very  elaslic,
and thtis elasticity: increases in a greater
proportion than the th t hat ich Iptroduces
it; uo:Iless,:therefore, some ver:t  b  fireely
allowed,..steam  wicil burst,- the  vessel
whicth coilffifes it.
Q.  Is AIR a goad' CONDUGCT9Qra'2
A.  No; air is a very brad conductor;
and is heated (like water) by conlvectionm.
Q.  Irow is a ROOM WAARMED by a STOVE?
A.  The air nearest tle fire is made
hotfirst and rises; cold air then descends,
is heated, and ascends in like manner;
and this interchange goes on till all thle
air of the room  is warmed.  (See p. 56.)
Q.  TThy are FIRES placed on the FLOOR of a
room00  and not towards the CEILING?
A. Because heated air always ascendls.  If, therefore, the fire were  not
near ih,e floor, the air of the lowver part of
the room would never be heated by the
fire at all.
Q.  If you take a POKER out of the fire, and
hold the IIOT END DOWNWAR.DS, why is t]he HANDLE
intensely ITOT?
A.  Because the hot end of the poker
heats the air around it: and this hlot air
(in its ascent) scorches the poker and the
hand wlhich holds it.
10




218    COMMUNICATION OF HEAT.
Q.  Hfow should a RED-HOT POKER be carried,
o as not to BURN our fingers?
A.  With the hot end upwards; for
then the air (heated by the poker) would
not pass over our hand and scorch it.




PART II,
A I R.
CHAPTER XX.
THE ATMOSPHERE.
Q. Of what is atmospheric AIR composed?
A. Principally of two gases, oxygen
and nitrogen, mixed together in the
following proportion: viz., 1 gallon of
oxygen to 4 of nitrogen.
It must not be forgotten that the air contains small
quantities of other gaseous substances also, as vapor of
water, carhbonic acid, and ammonia.
Q.   WThat do you mean by a GAS?
A.   A  permanent elastic fluid  resembling air.
N. B. MOST CeGSES ARE INVISIBLE OR COLORLESS, LIKE AIR.,
" PERMANENT,"-In this respect gas differs from vapor,
which is not permanent; for vapor may be easily condensed by cold into a liquid, but gas never changes its
gaseous form.
" ELASTIC,"-In this respect gas differs from a liquid,
which is almost inelastic; whereas gas is exceedingly
elastic.
" RESEMBLING AIR,"  or aeriform.- The word "Gas"
means air, but air is a compound of two gases. Some
few gases are visible, as CHLORINE, which is a greenish
yellow.
219




220                 AIR.
Q.   What is the dfference between a GAS and a
LIQUID?
A.  Gases are elastic, but liquids n7ot.
Q.  Illustrate what is meant by " the ELASTICITY
of GAS.)"
A.  If fiom  a vessel full of gas half
were taken out —the other half would immediately spread itself out, and fill the
same space as was occupied by the whole.
Q.  Prove that a LIQUID is NOT ELASTIC.
A. If from a gallon of water you take
half, the remaining 4 pints will take up
only half the room that the whole gallon
previously did: a liquid, therefore, is not
elastic like gas.
Strictly speaking, a liquid is slightly elastic; inasmuch
as it may be compressed and will afterwards recover its
former dimensions.
Q.   W'hat are the uses of the OXYGEN of the air'
A.  To support combustion and sustnain life.
Q.  IThat is meant, when it is said, that thd
OXYGEN of the air "SUPPORTS COMBUSTION?"
A.  It means this: It is the oxygen
of the air which makesfuel burin.
Q.  How does the OXYGEN of the air make FUEL
BURN?
A.  The fuel is decomposed (by heat)
into  hydrogen  and  car'bqn; and  these
elements combinining with the oxyzgen of
the air produce combustion.




GASES.              221
Q.  What GAS is produced by the combination
of carbon and oxygen?
A. CARBONIC ACID GAS. (See p. 43.)
Q.  What becomes of the HYDROGEN of the
FUEL?
A.  The hydrogen of the fuel combines
with the oxygen of the air, and forms
WATERY VAPOR; but the combination is
attended by the production of flame,
owing to the very inflammable nature
of hydrogen gas.
Q.  What becomes of the NITROGEN of the air,
amidst all these changes and combinations?
A.  The nitrogen escapes unchanged,
to be again mixed with oxygen, and converted into coinmon AIR.
Q.  What is meant, when it i. said, that oxYGEN "L SUSTAINS LIFE 2.7
A. It means this: If a person could
not inhale oxygen, hle would die.
Q.  What GOOD does this inspiration of OXYGEN
do?
A. 1st-It gives vitality to the blood:
and
2dly-It is the cause of animal heat.
Q.  How is FOOD converted into BLOOD?
A. After it is swallowed, it is dissolved in the stomach into a grey pulp,.
called CHYME; it then passes into the intestines, and is converted by the " bile"
into a milky substance, called CHYLE.




222                 AIR.
Chyme-pronounce kyme-chyle pronounce kyle —e"A
as mle syllable.
Q.  What BECOMES of the milky substance
called CHYLE?
A. It is absorbed by the vessels called " lacteals," and poured into the veins
on the left side of the neck.
Lac'teals-pronounce Lac'-te-als.
Q.  IWhat becomes of the chyle, AFTER it is
POURED into the VEINS?
A.  It nzingles with the blood, and is
itself converted into blood also.
Q.   How does the OXYGEN we inhale MINGLE
with the BLOOD?
A.  The oxygen of the air mingles
with the blood inl the ltngs, and converts
it into a bright red color.
Q.   What color is the blood BEFORE it is oxidized in the lungs?
A. A darkc purple. The oxygen turns
it to a bright red.
Oxidized, i. e., impregnated with oxygen.
Q.  W'hy are PErtSONS  SO PALE, who live in
CLOSE ROOMS and CITIES?
A. Because the blood derives its
redness fiomn the oxygen of the air inhaled; but, as the air in close rooms and
cities is not fresh, it is dfJicient in oxygen,
and cannot turn the blood to a beautiful
bright red.
Q.   Why are PERSONS, who live in the OFEN
AIR and in the country, of a RUDDY complexion?




BLOOD.                223
A    Because  they  inhale  fresh  air
which has its full proportion of oxygen:
and the blood derives its bricght red color
from the oxygen of the air inhaled.
Q.   Why is not the air in CITIES SO FRESH as
that in the cOUNTRY?
A.  Because it is impregnated  with
the breath of its numerous inhabitants,
the odor of its seiwers, the snmoke of its
fires, and many other impurities.
Q.  fow does OXYGEN convert the color of blood
into a bright RED?
A.  The coloring matter of the blood
is formed by very minute globules floating in it; the oxygen (uniting with the
coats of these globules) makes them nzillcky
-and the dark  coloring matter of the
blood  (seen  through  this milky  coat)
appears of a bright red.
Exp.:-If you put some dark venous blood into a milky
glass, and hold it tiup towards the light, it will appear of a
bright florid color like arterial blood.
Q.  How does the COMBINATION of OXYGEN with
the BLOOD produce animal HEAT?
A. The principal element of the
blood is carbon; and this carbon (combining with the oxygen of the air inhaled)
produces carbonic acid gas, in the same
way as burning fuel.  (See p. 43.)
Q.   lrhat becomes of the NITROGEN of tle air,.fter the oxygen enters the blood?




224                    AIR.
A. It is thrown out from the lungs
unchanged, by the act of breathing; to
be  again  mixed  with  oxygen and  converted into common AIR.
Q.   Why does the vitiated air (after the oxygen has been absorbed) COME OUT of the MOUTH, and
not sink into the stomach?
A. Because a mechanical provision
is made in the upper part of the windpipe and gullet for this purpose.
N. B. The lungs are a hollow, spongy mass, capable of
confining air and of being dilated by it. They are so situated in the thorax (or chest), that the air must enter into
them, whenever the cavities of the thorax are enlarged.
The process of breathing is performed thus: When we
INHALE, the thorax (or chest) is expanded; in consequence
of which, a vacuum is formeLd round tile lungs, and heavy
external air instantly enters (through the mouth and
throat) to supply this vacuum.
When we EXHALE, the thorax contracts again; in consequence of which, it can no longer contain the same quantity of air as it did before; and some of it is necessarily
expelled. When this expulsion of air takes place, the lungs
and muscular fibres of the wind-pipe and gullet contract in
order to assist the process.
Q.  If (both in combustion and respiration) the
OXYGEN of the air is CONSUMED, and the NITROGEN
REJECTED- Why are not the pROPOraTIONS of the
AIR DESTROYED?
A. Because the under surface of vegetable leaves (during  the  day) gives out
oxygen; and thus restores to the air the
very element of which it has been deprived.




VEGETABLES.               225
Q.    Vt~hence do leaves OBTAIN  the oxygen
which they exhale?
A.  From  the carbonic acid absorbed
by the roots from the soil, and carried to
the leaves by the rising sap.
N. B. Carbonic acid (it must be remembered) is a
compound of carbon and oxygen.
Q.  How do plants contrive to absorb carbonic
acid Jrom the soil?
A. It rises (by capillary attraction)
throughl the small fibrous roots, after it
has been dissolved in the soil by water.
Q.   Whence does the SOIL obtain carbonic acid?
A.  Ist-From the air; firom which it
is driven by falling showers:
2dly —From  the decomposition of vegetable and animal matters, which always produces this gas in abundance:
and
3dly-All lime-stone, chalk, and calcareous stones, contain vast quantities of
carbonic acid in a solid state.
Calcareous, i. e., of a limy nature.
Q.  If leaves throw of the OXYGEN of the carsonic acid, what becomes of the carbon?
A. It is retained to give firmness and
solidity to the plant itself.
Q.  Show how God has made ANIMAL life dependent on that of VEGETABLES.
A.  Animals require oxygen to keep
them  alive, and draw  it firom the air by
10o




226                AIR.
inspiration: The under surface of leaves
gives out oxygen; and thus supplies the
air with the very gas required for the
use of animals.
Q.  Show how God has made VEGETABLE life
dependent on that of animal.
A. Plants require carbonic acid,
which is their principal food; and all animals exhale the same gas from their
lungs. Thus plants supply animals with
oxygen, and animals supply plants with
carbonic acid.
Q.  How is AIR HEATED?
A. By " convective currents."
Q.  Explain what is meant by " CONVECTIVE
CURRENTS."
A. When a portion of air is heated,
it rises upwvards in a current, carrying
the heat with it; other colder air succeeds,
and (being heated in a similar way) ascends also: These are called " convective
currents."
(" Convective currents;" so called from the Latin words,
cum-vectus (carried with); because the heat is "carried
with" the current.)
Q.  Is AIR HEATED by the RAYS of the sux?
A.  No; air is not heated (in any sensible degree) by the action of the sun's
rays passing through it.
Q.  Why then is the AIR HOTTER on a;SUNNI
DAY, than on a CLOUDY one?




CONVECTION.            227
A.  Because the sun heats the surface
of the earth, and the air (resting on the
earth) is heated by contact: as soon as it
is heated it ascends; while its place is
supplied by colder portions which are
heated in turn also.
Q.  IJ'AI be a BAD CONDUCTOR, why does hot
IRON become COLD by EXPOSURE to the AIR?
A.  Because it is made cold-I stBy "convection;" and 2dly-By "radiation."
Q.  How is hot iron made cold by CONVECTION?
A.  The air resting on the hot iron
(being intensely heated), rapidly ascends
with the heat it has absorbed; colder air
succeeding absorbs more heat and ascends also; and this process is repeated
till the hot iron is cooled completely down.
Q.  How is hot iron cooled by RADIATION?
A. While its heat is being carried off
by " convection," the hot iron throws off
heat (on all sides) by radiation also.
Q.  What is meant by RADIATION?
A. Heat emitted (in all directions)
from any surface by rays.
Q.  Hfow is BROTH COOLED by being left exposed to the AIR?
A. It throws off some heat by radiation; but it is mainly cooled down by
convection.




228                  AIR.
Q.  How is hot BROTH cooled (down by coNv'Ea
TION 
A.  The air resting  on the hot broth
(being heated) ascends; colder air succeeding absorbs more heat, and  ascends
also; and this process is repeated till
the broth is made cool.
The particles on the surface of the broth sinlk as they
are cooled down, and warnmer particles rise to the surface;
which gradually assists the cooling process.
Q.   Why is hot TEA and BROTH COOLED faste?
by being  STIRRED about?
A.  1st-Because the agitation assists
in  bringing  its hottest particles  to  the
surface.
2dly-The  action of stirring agitates
the air, and brings it more quickly to the
broth or tea: and
3dly —As the hotter particles are more
rapidly brulght into contact with the
air, therefore, convection is more rapid.
Blowing tea or broth cools it also. (See p. 168.)
Q.  If a shutter be closed in the day-time, the
stream of lighrlt (piercing through the crevice) seems
in CONSTANT AGITATION.  HVIIY is this?
A.  Because little motes and particles
of drtst (thrown  into  agitation  by  the
violence of the convective currents) are
made visible by the strong beam  of light
thrown  into the room  through the cre.
vice of the shutter.




PRESSURE OF AIR.          229
Q.  TW'y is the GALLERY of a CHURCH or the.
Are HIOTTER than the AISLE or pit?
A.  Because the hot air ascends from
the bottonm to the top of the builirg;
while cold air flows to the bottowz from
the doors and windows.
Q.  Why do persons who ascend in balloons
feel inten:se pain in their eyes and ears?
A. Because the air of the upper
regions is nore rarefied  than that on the
earth; and the air inside their bodies.
(seekingr to become of the same rarity)
bursts througoh their eyes and ears, producin( inteise pain.
Q.  Why is it often PAINFUL and difficult t6
BREATHE, on a MOUNTAIN-TOP?
A. Because the pressure of air on the
mountain-top is not so great as it is on
the plain; and the air inside our bodies
(seeking to become of the same ratity)
bursts throutgh the pores of the body and
produces great pain.
Q.  IWhy do we feel OPPRESSED just PREVIOUS
to a storm?
A.  Because the air is greatly rarefied
by heat and vapor; and the air inside us
(seeking to become of the same rarity)
produces an oppressive and suffocating
feeling.




230                AIR.
Q.   Why do DIVERS, when they are under
water, szffer great pain in their eyes and ears?
A.  Because the air at the bottom of
the sea is more dense than the air on the
surface; and (till the air inside the diver's
body is settled into the same density) he
feels oppressed with pain, especially in
the ears.
Q.  Why is this PAIN felt especially about the
EARS of a DIVER?
A.  Because the ear is fitted with a
small membrane called the drumn(ortym'panurn), through which the dense] air
bursts: The rupture of this membrane
very often produces incurable deafness.
When the diver is not in a bell the dense water bursts
into his ears and ruptures the tympanum.
Q.  Why do our CORNS ache just previous to
RAIN?
A.  Because our feet swell from  the
sudden depression in the density of air;
and the hard corn (not being elastic) is
painfully stretched and pressed.
Some of this pain is due to electricity.
Q.  Howl do you know that the density of tht
air is lowered, previous to a storm?
A. Because the mnercury of a barometer rapidly falls.
Q.  Why do CELLARS feel WARM in WINTEI?
A. Because the external air has not




RUST.              231
free access into them; in consequence of
which, they remain almost at an even
temperature-which (in winter tine) is
about 10 degrees warmer than the external air.
Q.  Why do CELLARSfeel COLD in SUMMER?
A, Because the external air has not
free access into them; in consequence
of which, they remain almost at an even
temnperature-which (in summer time) is
about 10 degrees colder than the external air.
Q.  Why does AIR rust iRON?
A.  Because the oxygen of the air
combines with the surface of the metal,
and produces oxide of iron; which is
generally called " rust."
An oxide of iron, copper, &c., is oxygen in combitnatimo
with iron, copper, &c.
Q.  W/Vhy does hot iron SCALE and PEEL o0f
when struck with a EAMMER?
A. Because the oxygen of the air very
readily unites with the surface of the
hot iron, and forms a metallic oxide (or
rust), which scales off when struck with
a hammer.
Q   Does iron RUST in DRY air?
A.  No; iron undergoes no change
in dry air.




232                  AIR.
Q.   Why do STOVES and FIRE-mIrONS become
RUSTY in rooms, which are not ocCUPIED?
A.  Because  the air is damp;  and
moist air oxidizes iron and steel.
Oxidizes, i. e., rusts.
Q.  In what part of the year is it most dificWlt
to keep STOVES and FIRE-IRONS BRIGHIT?
A. In autumn and 2winter.
Q.   Why is it more difficult to keep STOVES and
FIRE-IRONS bright in AUTUMN and W\INTER than in
spring auld summner?
A. Because the capacity of the air
for holding water is constantly on the
decrecase, after the summer is over; in
consequence of which, vapor is deposited
on everything with which the air comes
in contact.
Q.   W'hy does GREASING iron prevent its be
coming RUSTY? 
A.  Because grease prevents the humidity of air from   comingr in  contact
with the surface of the iron.
Q.   Why do not STOVEs rust so frequently as
POKERS and TONGS?
A. Because stoves are generally covered twith plumbago, or black lead.
Q.   W'hat is plumbago, or black lead?
A.  A  mixture of' charcoal and iron.
Plumbago (strictly speaking) is a chemical union of
caibon, and iron, in the following proportions:-91 parts
carbon and 9 iron. But the B.ACK LEAD se.d in shlop is a
mixture of charcoal and iron filings.




METALS.                 233
N. B. A most excellent varnish to prevent rust is
made of 1 pint of fat oil varnish, mixed with 5 pints of
highly rectified spirits of turpentine, rubbed on the iron
or steel with a piece of sponge. This varnish may be applied to bright stoves, and even mathematical instruments,
without injuring their delicate polish.
Q.   Why does ornamental STEEL (of a purple
or LILAC color) rust more readily than polished
WHITE steel?
A.  Because  the  lilac  tinge  is produced by partial oxidation; and. the
process which forms rusts has, therefore,
already commenced.
Q.  How can lilac STEEL be kept FREE from
RUST?
A.  By keeping it in a very dry place.
Q.  If DRY AIR contains OXYGEN, why does it
NOT RUST IRON, as well as MOIST air?
A. Because moisture is always needed, in order  to  bring  into  action  the
affinity of oxygen for steel.
Q.  Do any OTHER metals (besides iron) combine rapidly with oxygen?
A. Yes; copper, lead, mercury, and
even silver to some extent.
Q.   Why does COPPER TARNISHI?
A. The tarnish of copper is caused
by its oxidation: that is, the oxygen  of
the air combines with the surface of the
copper, and (instead of rusting it) covers
it with a dark tarnish.
Q.   Why does LEAD become of a DARKER  a.1
by being exposed to the air?




234               AIR.
A.  Because the vapor of the air combines with the lead, and oxidizes its surface; but instead of becoming rusty, the
surface assumes a darker hue.
Q.  Why does LEAD lose its BRIGHTNESS, and
become DULL, by being exposed to the air?
A.  The dullness of the lead is caused
by the presence of a carbonate of the
oxide.  When  the  oxide is formed, it
attracts carbonic acid from  the air, and
(combinitlg with it) produces a carbonate,
which gives the dull tint to old lead.
Q.  Why is it difficult to keep SiLVER BRIGHT?
A. Because the vapor of the air oxidizes its surface, and tarnishes it.
Q.  ]Why do silver TEA-POTS and SPOONS tarnish more quickly than silver ore or bullion?
A.  Because alloy of some baser metal is used, to make them  more hard and
lasting; and  this alloy  oxidizes more
quickly than silver itself.
Q.  wThy does GERMAN silver turn a dingy
yellow in afew hours?
A. Because  German  silver  has a
great affinity for oxygen; and shows its
oxidation by a sickly yellowz tarnish, instead of rust.
Q.  If quicksilver (or mercury) will tarnish lik
copper and lead-why does it preserve its BRILLIANCY
in BARO11METERS and THERMOMETERS 2




OXIDATION-PLATINUM.              235
A.  Because the air is excluded; and
no moisture can come in contact with it,
to oxidize (or tarnish) it.
Q.  Is GOLD affecled by the atmosphere?
A. Not readily; gold will never
combine with oxygen of itself, (i. e.,
without aid.)
Q.  WIICH of the METALS is capable of resisting
oxidalion alltogelher?
A.  Plat'inum;  in  consequence  of
which, the graduated  arcs of delicate
" instruments-for-observation " are made
of plat'inum instead of any other metal.
Q.  /Why is PLAT'INUM used for the graduated
arcs of delicate mathematical instruments, instead of
any other metal?
A. Because it will never oxidize;
but retains its bright sufitce in all weathers, fiee fi'oin both riust and tarnish.
Q.  Befrore platinum was discovered, which of
the metals was employed for the same purpose?
A.  Gold.
Plat'inurm (a white metal), so called from " plata,"
the Spanish word for silver. It was introduced firom
South Ameirica into England by Mr. Wood, (A. D. 1749.)
Q.  For what other SCIENTIFIC purpose is PLAT'.
INUM 1o011 used?
A. For crucibles in which acids are
employed: and for galvanic batteries.
Q.   IVhy/ are CRUCIBLES (in which acids are
enployed) made of PLAT'INUM?




236                 AIR.
A. Because the acid would act upon
other nmetals, or upon glass; and prevent
the experimenter's success.
Q.   Which of the METALS hace the GREATEST
iffinity for OXYGEN?
A.  Those called potasciunm  and so'.
diunz.
Potas'sium and so'dinm derive their aarmes from potash
and soda. Potas'sa is the oxide of potas'siumi and soda
is the oxide of so'dium.
Q.  How is the affinity of potas'sium and so'dium for oxygen shown?
A.  They decompose water immediately
they are brought into contact with it.
Q.  Hrhat EFFECT has POTAS SIUM on WATER?
A.  It catches fire thie moment it is
thrown  into water, and  burns with a
vivid  flanme-which is still futrther increased by the combustion of hydrogen,
separated from the water.
N. B. Water is composed of oxygen and hydrogen;
and potas'sium separates the two gases.
Q.   What efect has soD'muM on WATER?
A.  It does not takecfire, as potassium
does; but undergoes very rapid oxidation.
Q.  Is the FURR Of KETTLES an oxide?
A.  No; the fun' (or deposit of boiling water) is a precipitate of lism  and
mineral salt, separated friom  the water
by the process of boiling.




FURR.               237
Q.  Is not this FURR of boiling water often
DANGEROUS?
A. Yes; especially in tubular boilers,
such as those employed in railways.
Q.  Why is this FUnrt especially TnOUBLESOME
in RAILWAY en gines?
A. Because it is a bad conductor of
heat; in consequence of which, it hinders the evaporating  effect of the fire,
and prevents the economy of fuel.
Q.  Why is this FUrvt  especially DANGEROUS
in RAILWAY egrines?
A. Because, when it is deposited in
the boilers, they are likely to become
over-heated; and then explosion will take
place, fi-ro the sudden generation of
highly elastic steam.
Q.  Why cannot RAILWAY engines be fed with
BRACKISH WATER?
A.  Because brackish water contains
nimneral salt; which makes a much lar.
ger deposit of furr than water which
contains only vegetable matters.




238        CARBONIC ACID GAS.
CARBONIC ACID GAS.
CHAPTER XXI.
Q.  WThat is CARBONIC ACID GAS?
A.  A  gas formed by the  union  of
carbon and oxygen: It used to be called
ts FIXED AIR.7)
3 lbs. of carbon and 8 lbs. of oxygen will form 11 lbs. of
carbonic acid.
Q.   Under what circumstances does CARBON
most readily UNITE with OXYGEN?
A.  lst — When  its  tenmperature  is
raised:  Thus if carbon be red-hot, oxygen will most readily unite with it:
and
2dly-When it forms part of the fluid
blood.
Q.  WThy do oxygen and carbon so readily.nite in the BLOOD?
A. Because the atoms of carbon are
so loosely attracted by the other materials
of the blood, that they unite very readily
with the oxygen of the air inhaled.
Q.  Is carbonic acid WHOLESOME?
A.  No;  it is fatal to animnal life;
and (whenever it is inhaled) acts like a
narcotic poison-producing drowsiness,
which sometimes ends in death.
Q.  Iow can any one KNOW, if a place be imp
tested with CARBONIC ACID GAS?




VITIATED AIR.           239
A. If a pit ior well contain carbonic
acid, a candle (let down into it) will be
instantly extinguished.  The rule, therefore, is this —Where a candle will burn,
a man can live; but what will extinguish
a candle, will also destroy life.
Q.  WThy does a MINER. lower a CANDLE into
a mine, before he descends?
A. Because the candle will be extinguished, if the mine contains carbonic
acid gas: but if the candle is not extinguished, the mine is safe, and the man
may fearlessly descend.
Q.  Wthy does a CROWDED ROOM produce
HEAD-ACHE?
A.  Because we breathe air vitiated
by the crowd.
Q.  Why is the AIR of a room VITIATED by a
CROWD?
A.  Because it is deprived of its due
proportion of oxygen, and laden with
carbonic acid.
Q.  How is the air of a room afected thus by
a crowd?
A. The elements of the air inhaled
are separated in the lungs: —the oxygen
is converted in the blood into carbonic
acid; and the carbonic acid (together
with the nitrogen) is thrown back again
by the breath into the room.




240        CARBONIC ACID GAS.
Q.  Is ALL the NITROGEN REJECTED by the
lungs?
A.  Yes; all the nitrogen of the air
is always expired.
Q.  Why is a CROWDED ROOM UNWHOLESOME?
A. Because the oxygen of the air is
absorbed by  the  lungs; and  carbonic
acid gas (which is a noxious poison) is
substituted for it.
Q.  MArention, the historical circumstances. so
well known in connexion with the "BLACK HOLE
of CALCUTTA."
A.  In the reign of George  II., the
Raja (or Prince) of Bengal* marched
suddenly to Calcutta, to drive the English from the country; as the attack was
unexpected, the English were obliged
to submit, and 146 persons were taken
prisoners.
Q.  What became of these prisoners?
A. They were driven into a place
about 18 feet square, and 15 or 16 feet
in height, with only two small grated
windows. 123 of the prisoners died in
one night; and (of the 23 who survived)
the larger portion died of putrid fevers,
after they were liberated.
Q.  Why were so many persons SUFFOCATED in7
* The Snur Raja, at Dovlat; a young man of violent passions, who had but just sr ccceded to the throne. A. D. 1756.




JUNGLES.            241
a few hours, from confinement in this close,,tot PRISON-HIOLE 2
A.  Because the oxygen of the air was
soon consumed by so many lungs, and
its place supplied by carbonic acid, ex.haled by the hot breath.
Q.  Why did the captives zn the BLACK HOLE
die SLEEPING?
A.  1st-Because the absence of oxygen quickly affects the vital functions,
depresses the nervous energies, and produces a lassitude which ends in death:
and
2dly - Carbonic acid gas (being a
narcotic poison) produces dcrowsiness and
death, in those who inhale it.
Q.  Why are the JUNGLES of Java and Ilindostan so FATAL to life?
A. Because vast quantities of carbonic acid are thrown off by decaying
vegetables in these jungles; and (as the
wind cannot penetrate the thick brushwood to blow the pernicious gas away)
it settles there, and destroys animal life.
Q.  Why do persons in a crowded CHUaCH feel
DROWSY?
A. 1st-Because the crowded congregation inhale a large portion of the
oxygen of the air, which alone can sus.
tain vitality and healthy action: and
11




242       CARBONIC ACID GAS.
2dlv  The air of the church is im.
pregnated with carbonic acid gas, which
(leing a strong narcotic) produces drowsmess in those who inhale it.
Q.  Why do PERSONS who are muclh in th4
OPEN AIR enjoy the best HEALTH?
A. Because the air they inhale is
nmuch more pure.
Q.  Why is COUNTRY AIR more PURE than the
air in CITIES?
A. 1st-Because there are fewer
inhabitants to vitiate the air:
2dly —There are more trees to restore
the equilibrium  of the vitiated air: and
3dly-The  free  circulation  of air
keeps it pure and wholesome: (In the
same way as running streams are pure
and wholesome, while stagnant waters
are the contrary.)
Q.  Why does the SCANTINESS of a country
POPULATION render the COUNTRY AIR more PURE?
A. Because the fewer the inhabitants,
the less carbonic acid will be exhaled;
and thus country people inhale pure
oxygen, instead of air impregnated with
the narcotic poison, called carbonic acid
gas.
Q.  Why do TREES and FLOWERS help to make
country AIR WHOLESOME?
A. 1st -Because trees and flowers




COUNTRY AND CITY AIR.    243
ttbsorb the carbonic acid, generated  by
the lungs of animals, putrid substances,
and other obnoxious exhalations: and
2dly- Trees and flowers restores to
the air the oxygens, which has been inhaled by man and other animals.
Q.  WVhy is the AIR of CITIES LESS wholesome,
than COUNTRY air?
A. ist-Because there are more inhabitants to vitiate the air:
2dly-The  sewers, drains, bins, and
filth of a city, very greatly vitiate the
air:
3dly —The streets and alleys prevent
a free circulation: and
4thly —There are fewer trees to absorb the excess of carbonic acid gas,
and restore the equilibriitin.
Q.  WIhy are PERSONS, who live in CLOSE
ROOMS and crowded CITIES, generally SICKLY?
A.  Because the air they breathe is
not pure, but is (in the 1st place) defective in oxygen; and (in the 2d) is impre-gnated with carbonic acid gas.
Q. WIhere does the CARBONIC ACID of close
RooMs and CITIES COME f'-om?
A. From the lungs of the inhabitants,
the sewers, drains, and other like places,
in which organic substances are undergoing decomposition.




244       CARBONIC ACID GAS.
Q.  What BECOMES of the CARBONIC ACID Of
crowded cities?
A.  Some of it is absorbed by vegetables; and the rest is bloiwn  naway by the
wi?ld, and diffused through the whole
volume of the air.
Q.  Does not this constant diffusion of carbonic
acid a.#ict the PURITY of the WHOLE AIR? 
A.  No; because it is wafted by the
wind fi-om  place to place, and absorbed
in its passage by the vegetable wvorld.
Q. What is CHOKE DAMP?
A.  Carbonic acid gas accumulated at
the bottom of wells and pits, which renders them noxious, and often fatal to
life.
Q.  Why is not this carbonic acid TAKEN UP by
the AIR and DIFFUSED, as it is in cities?
A.  Because (being heavier than comnmon air) it cannot r'ise from  the iwell or
pit: and no wind can get to it, to blow
it away.
Q.  Why are PERSONS sometimes'KILLED by
leaning over BEER VATS?
A.  Because vats (where  beer has
been made) catain a large quantity of
carbonic acid gcrs, produced by the "vinous fermentation" of the beer; and
when a man incautiously leans over a




BEER VATS-CHARCOAL.           245
beer vat, and inhales the carbonic acid,
he is immediately killed thereby.
Q.  Why are PERSONS often KILLED, who enter
BEER VATS to clean them?
A.  Because carbonic acid (beinr heavier than atnospyheric air ) often rests upon
the bottonm of a vat: when, therefore, a
person enters the vat, ard stoops to clean
the bottom, he inhales the pernicious gas,
which kills him.
Q.  HWhy are PERSONS sometimes KILLTED, by
having a CI3ARCOAL FIRE in their bedrooms?
A.  Because the carbon of the burning
charcoal unites with the o.ygen of ti'e air,
and forms carbonic acid gas, wllich is a
narcotic poison.
Q. If carbonic acid settles at the BOTTO~M of a
room, how can it injure a person LYING upon a BED,
raised considerably above the floor?
A.  Because all gases diffause them.
selves througw, ca'ch other, as a drop of
ink would diffuse itself throuth a cup of
water.  If, therefore, a person slept for
6 or 8 hours in a room containing carbonic
acid, quite enough of the gas will be
difflsed throughout the room to produce
death.
The heat of the fire assists the process of diffusion.
Q.  What aie the chief souricES of CARIBONIC
ACID?




246        CARBONIC ACID GAS.
A.  lst-The breath of animals.
2dly-The decomposition of vegetable
and animal matter.
3dly-Lime-stone, chalk, and all calcareous stones,-in which it exists in a
solid form.
Q.  From which of these sources is CARrcNIC
ACID most likely to ACCUMULATE to a noxious exlte:t?
A.  From  the fermentation and putrefaction of decaying vegetable and aninmal matters.
Q.   How can this ACCUMULATION of CARBONIC
ACID be PREVENTED?
A.  By throwing quick-lime into places, where such fermentation  and putrefaction are going on.
Q.  Houz,t will QUICK-LIME PREVENT the accumulation of CARBONIC ACID?
A.  Quick-lime  will absorb the carbonic acid; and produce a combination
called "carbonate of lime."
Q.  Does not heavy RAIN prevent the ACCT MULATION of CARBONIC ACID, as well as quick-lime?
A.  Yes;  an  abundant  supply  of
water will prevent the accumulation of
carbonic acid, by dissolving it.
N. B. Red heat (as a pan of red-hot coals, or a piecu
of red-hot iron) will soon absorb the carbonic acid gas,
Iccumulated in a pit or well.
Q.   "'hat effect has CARBONIC ACID on the WAtER in which it is dissolved?




EFFERVESCENCE.              247
A.  It renders it slightly acid to the
taste.
Q.  Can the CAPACITY of water for dissolving
carbonic acid be increased?
A.  Yes. Carbonic acid may beforcecd
into water by pressure to a considerable
extent.
Q.  To what practical USES has this capaczty
of water (for dissolving carbonic acid) been applied?
A.  Effervescinfg draughts are made
upon this principle.
Q.  Explain the cause of EFFERVESCENCE in
these beverages?
A. The carbonic acid of the beverage
(being prevented by the cork from escaping) is forced into the liquor by pressure, and absorbed by it: but when the
cork (or pressure) is removed, some of
the carbonic acid flies off in bubbles or
effervescence.
Q.  Why does AERATED WATER effervesce when
the CORK is removed?
A.   While  the  bottle remains corked, carbonic acid isforced into the water
by pressure, and absorbed by it: but,
when the cork (or pressure) is removed,
some of the carbonic acid flies off ill
effervescence.
Q. Why does SODA WATER effervesce?
A. In soda water there is forced 8




~48       CARBONIC ACID GAS.
times its own bulk of carbonic acid gas,
which makes its escape in effervescence,
as soon as the cork is remroved.
Q.  Why does GINGER POP fly about in froth,
when the string of the cork is cut?
A. Because it contains carbonic acid
gas.  While the cork is fast, the carbonic
acid is forced into the liquor; but when
the pressure is renmoved the gas is given
off in effervescence.
N. B. All vinous fermentation produces carbonic acid.
Q.  Why does BOTTLED ALE froth more than
DRAUGHT ale?
A. Because the pressure is greater
in a bottle than in a tub which is; continually tapped; and effervescen:c is always increased by pressure.
Q.  What produces the FROTH of' BOTTLED
PORTER?
A.  Carbonic acid generated by the
vinous ferntietation of the porter:  This
gas is absorbed by the liqutor, so long as
the bottle is well corked; but is given off
in froth, when the pressure of the cork is
removed.
Q.  What gives the pleasant ACID taste to soda
water, ginger beer, champagne, and cider?
A.  The presence of carbo.,,ic acid,
generated by fermentation; and liberat



SPRING WATER-ALCOHOL.    249
ed by effervescence, when the pressure
of the cork is removed.
Q. TVhy does fresh SPRING eWATER SPARKLE,
when poured from one vessel to another?
A. Because fresh spring and pump
water contain carbonic acid; and it is
the presence of this gas which makes
the water sparkle.
Much of the froth and bubbling of ale, beer, wATER,
&c., wihen they are " poured high," is due to simple mechanlicat action.
Q. Wlhat is the FERMENTATION of BEER and
WINE?
A.  The escape of carbonic acid, produced by the change of sugar into al'cohol.
Q.  TI/at iS AL'COHOL?
A. The spirit of beer and wine,
obtained by fermentation.
Q.  of uwhat ELEMENTS is AL'COTIOL composed?
A.  Of carbon, oxygen, and hydrogen.
Of AL'coiorL, 4 parts are carbon, 2 oxygen, and 6 hydrogen
Q.  IVWhat are the ELEMENTS of grape SUGAR?
A.  Carbon, oxygen, and  hydrogen,
all in equal proportions.
Q.  What CHANGES does SUGAR undergo by
FERMENTATION?
A. It is first decomposed, and then
its elements re-unite in different proportions, producing alcohol, carbonic acid,
and water.
Il1




250         CARBONIC ACID GAS.
Of SUGAR, one portion is alcohol; and anoth er carbonie
acid; as may be seen by the following table.
Carbh. Oxy. Hyd.
Every atom of anhydrous sugar contains 12 12 12
Two atoms of alcohol contain        8  4 12
Four atoms of carbonic acid contain  4  8  0
12 12 12
N. B. " Anhydrous sugar" is sugar dried at 300~
Q.  How does SUGARform AL'COHOL by fermentation?
A.   Two-thirds of its carbon and one.
third of its  oxygen  re-unite  with  the
hydrogen, and generate al'cohol.
Q.   How does SUGAR form CARBONIC ACID b.
fermentation?
A.  The  remaininlg  one-third  of its
carbon  and tiwo-thirds of its oxygen re
unite, and generate carbonic acid.
Q.   What BECOMES of the AL'COHOL which is
thus generated byfermentation?
A.  It mixes  with  the  water, and
forms the intoxicating part of beer and
wine.
Q. *What becomes of the CARBONIC ACID, which
is generated by fermentation?
A.  It makes its escape into the air.
Q.   Why is BARLEY MALTED?
A.  Because germination is produced
by the artificial heat; and in germination, the starch of the grain is converted
into sugar.




BARLEY-YEAST.              251
Q.   low is barley malted?
A.  It is nmoistened  with water, and
heaped rup; by which means, great heat
is produced, which  makes the barley
sprout.
(See "spontaneous combustion.")
Q. Why is not the BARLEY suffered to GIrow
as well as SPROUT?
A.  Because plants in the germ  contain more sugar than in any other state:
as soon as the germ puts forth shoots, the
sugar of the plant is consumed, to support the shoot.
Q.  How is BARLEY PREVENTED from SHOOTING in the process of MALTING?
A. It is put into a kiln, as soon as it
sprouts; and the heat of the kiln checks
or destroys the young shoot.
Q. hr hat is YEAST?
A.  The foam  of beer (or of some
similar liquor) produced byfer'mentation.
Q.  Why is YEAST used in BLREWING?
A. Because it consists of a substance
called glu'ten, undergoing putrefaction;
in which state it possesses the peculiar
property of exciting fermentation.
If the gluten were not in a putrefying state, it could
aot produce fermentation.
Q.  What is glu'ten?
A. A tough, elastic substance, comrn



252        CARBONIC ACID GAS.
posed of carbon, oxygen, hydrogen, and
nitrogen.
Q. Does MALT contain glu'ten?
A. Yes. The infusion of' malt, called
Cc sweet-wort" contains an abundance of
glu'ten; and tile yeast (which converts
its sugar into al'cohol) converts this glu'ten into yeast.
Q.  Why is YEAST needful in order to make
malt into BEER?
A. Because the presence of a putrefyingf body containing nitrogen is essential, in order to convert sugar into al'coliol.
Q.   Yhat FFFECT has yeast upon the swtrWORT?
A. It causes the SUGAR to be con.,verted into alcohol and carbonic acid;
and its GLUTEN into yeast.
Q.  WIhat change is produzce in gluten by ruTREFACTION?
A. Its elements are loosened from
their former conditions of conmbination,
and re-arranged (with the addition of
oxygen from the air) into a new series.
Q. What is the DIFFERENCE between FERMENTATION and PUTREFACTION?
A.  FERMENTATION  is a chance effected in the elements of a body composed of carbon, oxygen, and hydrogen,




PUTREFACTION.               253
Lwitlhout  nitrogen.   PUTREFACTION  is  a
change effected  in  the  elements of a
body composed of carbon, oxygen, hydrogen, and nitrogen.
Q.   What NEW COMPOUNDS are produced by
the chantge called FERMENTATION?
A.  Alcohol and  carbonic acid.-The
alcohol is still further changed  (unless
the process be checked) into ace'tic acid
or V'iler(lF.
Q.  WThat new compounds are produced by the
chance calledl PUTREFICTION?
A.   The carbon, oxygen, hydrogen,
and  nitrogen, of the original substance
(being  separated by decomposition) reunite in tile following manner. 1. Carbon
and oxygen unite to form  carbonic acid.
2. Oxygen  and  hydrogen unite to form
water.  3. Hydrogen and nitrogen unite
to form anrn-tonia.
iLzrtshorn is a solution of ammonia in water.
N. B. When bodies containing sulphur and phosphorus
putrefy, the sulphur and phosIAwrus unite with hydrotg,cn,
and form sudplhuretted and phosphurctted hyd(rogen gases.
Q.    Vhat BECOMES of these several products of
putrefaction?
A.  They  are all elastic bodies, and
escape into the air.
N. B. Invter is elastic and gaseous when in the condi-,
tion of vapor.
Q.   Wlhat is the cause of the OFFENSIVE SMELL
which issues from putrefying bodies?




254         CARBONIC ACID GAS.
A.'I'he evolution of ammonia, or of
sulphuraetted and phosphuretted hydrogoen
gases; all of which  have pungent and
offensive odors.
Q.   WVhy do boiled EGGS DISCOLOR a SILVER
SPOON?
A. Because they contain a small
portion of sulphur, which unites with the
silver (fbr which it has a great afinity)
and tarnishes it.
Both the white and yolk contain sulphur-the latter
more abundantly.
Q.   T;hat causes the ofensive smell of STALE
hard boiled ECGS?
A. Tile hydrogen of the egg combining with  the sulphur  and  phosphorus,
form  sulphuretted and phosphurettcd hydrogen; both of which gases  have an
offensive odor.
Of an egg 55 parts are carbon, 16 nitrogen, 7 hydrogen,
and the remaining 22 are oxygen, phosphorus, and sulphur.
Q.    Vxhy is it NOT needful to put YEAST into
GRAPE juice, in order to producefermentation?
A.  Because grape juice contains  a
sufficient quantity of'a nitrogoenized
substance (like yeast) to produce fermen.
tation.
Nitrogenized, i. e., containing nitrogen.
Q.   Why do NOT GRAPES ferment, whiie thej
tang on the VINE 




FERMENTATION.             255
A. Because the iwater of the juice
evap)orates through the skin, and allows
the grapes to shrivel and dry up, after
they are ripe.
Fermentation cannot occur unless the sugar be dissolved
in a sufficient quantity of water.
Q.  What is the FROTH or scuM of fermented
LIQUORS?
A. Putrefying glutinous substances
(of a nature similar to yeast), whllich rise
to the surface from their lightness.
Q.  TWhy is BEER FLAT if the cask be left open
too long?
A.  Because too much of the carbortic
acid gas (produced by fermentation) is
suffered to escape.
Q.   WVly are BEER and PORTER made STALE by
being exposed to the AIR?
A.  Because too much of the carbonic
acid gas (produced by fermentation) is
suffered to escape.
Q.  Why does BEER turn FLAT if the VENT PEG
be left out of the tub?
A. Because the carbonic acid gas escapes through the vent hole.
Q.  whay will NOT beer IRUN OUT of the tub till
the VENT PEG is taken out?
A. Because the upward pressure of
the external air (admitted through the
tap) holds the liquor back-not being




256         CARBONIC ACID GAS,
counterbalanced by any pressure of air
on the surface of the liquid.
The itpward pressure of air is illustrated by the following simple experinimnt:-Fill a wine glass withl water;
cover the top of the glass with a piece of vwriting paper
turn the glass upside down, and the water swill not run
out. The palper is used merely to give the air a medium
sufficiently dense to act against.
Q.   Why does the BEER RUN FREELY, immediately the VENT PEG is taken out?
A.  Because  air rushes immediately
throughlh the vcnt hole at the toi,  of tle tub,
to  counterbalance  the air admitted  by
the  tap; in consequence  of which  the
liquid  escapes  by  its own  downward
pressure.
Q.   IVLy does liquor flow reluctantly out of t,
BOTTLE held upside down?
A.  Because the upward press'wec of
the air prevents the liquor fiom  flowing
out.
Q.   Why should a bottle be held OBLIQUELY ill
order to be emptied of its liquor?
A.  Because air will then Jlowl  into
the bottle, and  help  the  liquor out, by
counterbalancingr the upwiardl pressure.
Q.   Why does wine (poured fiomn a bottle
QUICKLY) SPIRT about, without goilng  into  the
decanter?
A.  Because it fills the top of the decanter (like a cork), and  leaves no 1roor




YEAST-FERMENTATION.          257
for the air inside' to escape; the decanter,
therefore, (being full of air) refuses to
admit the swine.
Q.  Why does the EFFERVESCENCE of soda water
and ginger beer so soon go of?
A.  Because the carbonic acid, (which
produced the effervescence) very rapidly
escapes into the air.
Q. WVhy is BOILED WATER FLAT and insipid?
A.  Because the whole of the carbonic
acid is expelled by boiling, and escapes
into the air.
Q.  Why does YEAST make BREAD LIGHT?
A. Because it produces a species of
fermentation on the starch and glu'ten
of flour, as it does in the sugar of malt.
Q.  hIow does FERMENTATION make the DOUGH
RISE?
A.  During fermentation, carbonic acid
gas is evolved; but the sticky texture of
the dough will not allow  it to escape;
so itforces up little bladders all over the
dough.
Q.  WhTy is DOUGH placed BEFORE the FIRE?
A. 1st-Because the heat of the fire,
increases thefermentation; and
2dly —It expands the gas, confined in
the little bladders; in consequence of
which, the bladders are enllaed, and




258      CARBONIC ACID GAS.
the dough becomes lighter and inore po.
rous.
Q.  Ihy is BREAD HEAVY, if the dough be re.
moved from thefire?
A.  Because the dough gets cold, and
then the air in the bladders codiensesthe paste falls-and the bread becomes
close and heavy.
Q.  Wrhat causes the HEAT of FIRE?
A. The carbon offuel (wllen heated)
combines with the oxygen of the air, and
produces carbonic acid gas: Again, the
hydrogen of the fuel combining  with
other portions of oxygen, condenses into
water; by which chemical actions heat
is evolved.
Q.  What causes the HEAT of our own BODY?
A.  The carbon of our blood coLnbines
with the oxygen of the air inhaled, and
produces  carbonic  acid  gas; which
evolves heat in a way similar to burning fiel.
Q. qWhfence does the IIEAT of a DUNGHILL
arise?
A.  As the strawz, &c., of the dlnghill
decays, it uIndergoes fermentationt, which
produces carbonic acid gas; and heat is
evolved by a species of combustion, (as
in the two former cases.)




I ME- WATER.               259
Q. How does the formatwn of CARIONC ACID
(in all these cases) produce HEAT?
A. Carubonic acid has less power of
holding latent heat than carbon and oxygena have: When, therefore, these  elements are changed into carbonic acid,
latent heat is given off, and made sensible.
Q.  Why do persons throw LIME into BINS and
SEWERS, to PREVENT their offensive SMELL, in sumner time?
A.  Because they contain large quantities of carbonic acid gas, which readily
combines With linme; and producing " cabonate of linme," neutralizes the offensive
gases.
Q.   WAhy should WATER (used for washing) be
exposed to the air?
A. Because it is made more soft by
exposure to the air.
Most spring water holds lime in solution as a bicarbonate, in consequence of the presence of abundant carbonic
acid. Carbonic acid escapes by exposure to air-and the
lime is, consequently, deposited as a carbonate.
Q.   t7iy is hard WATER made more SOFT by
exposure to air?
A.  1st-Because  the  nmineral salts
(which cause its hardness) subside: and
2dly-Because the carbonic acid  of
the water makes its escape into the air,
Q.  How is the carbonic acid of water i'o
4duce?




260       CARBONIC ACID GAS.
A. From the presence of lime, which
is firequently held in solution by hard
water: When the carbonic acid escapers
by exposure to the air, the lime is deposited As a carbonate.
Q.  Why is HARD WATERt more agreeable to
DRINK than soft water?
A. Chiefly because it contains carbonic acid.
Q.  Why is water FRESH from the pump mare
8PARKLING, than after it has been driawn some time?
A.  Because water fresh from  the
pump contains carbonic acid, which soon
escapes into the air, and leaves the water flat and stale.
Q.  MWy is QUICK-LIME formed by burning
chalk and marl in a KILN?
A.  Because the carbonic acid (which
rendered it mild) is driven off by the
heat of the kiln: and the lime becomes
quick or caustic.
Q.  What is MORTAR 
A. Quick-lime mixed with sand and
water.
Q.'Wherein does LIME-STONE difer in appear
ance from quick-lime?
A. LIME-STONE is a hard, rocky sub.
stance; but aUICK-LIME a loose powder.
Q. Why does MORTAR become HARD after & fewo
days?




MORTAR- -CHOKE-DAMP.        261
A.  Because the lime re-inmbibes fiom
the air the carbonic acid  which had
been expelled byfire; and the loose powder again becomes as hard as the original lime-stone.
Q.  Explain iln what way MORTAR is adhesive.
A.  When the carbonic acid is expelled, the hard lime-stone is converted into
a loose povwder, which (being mixed with
sand  and water) becomes a soft and
sticky plaster; but as soon as it is placed
between bricks, it imbibes carbonic acid
again, and hardens into linme-stone.
CARBURETTED HYDROGEN GAS.
CIIAPTER XXII.
Q.  Tlhat is CHOKE-DAMP?
A. Carbonic acid gas accumulated
at the bottom of wells and pits. It is
called CHOKE damp, because it chokes (or
suffocates) every animal that attempts to
inhale it. (See p. 238.)
It suffocates without getting into the lungs, by closing
the outer orifice spasmodically.
Q.  What is marsh-gas or FIRE-DAMP?
A.  Carburetted hydrogen gas accu



262  CARBURETTED HYDROGEN GAS.
mulated on marshes, in stagnant waters,
and  coal-pits;  it is frequently  called
"inflammable air."
Q.  ~What is CARBURETTFD HYDROGEN GAS?
A.  Carbon combined with hydrogen.
Q.  fow mlay CARBURETTED HYDROGEN GAS
be PROCURED on marshes?
A. By stirring the mud at the bottom
of any stagnant 1)ool, and collecting the
gas (as it escapes upwards) in an invertedl glass vessel.
Q.  What is COAL GAS?
A.  Carburetted hydroqen extracted
from coals by the heat offire.
Q. - thy is carburelted hydroggen gas called
FIRE-DAMP or ifilammable air?
A. Because it very readily catches
fire and explodes, when a lightl is introduced to it.
Provided atmospheric air be present.
Q.  Why is carburetted hydromen gas frequent
4I called MARSII-GAS?
A.  Because it is generated in mea.
dozws and marshes fromrn putrefyino vegetable substances.
See ignis fatuus, p. 266.
Q.  What gas is evolved by the WICi of a
burning CA.NDLE?
A.  Carburetted hydrogen gas: The
carbon and hydr'ogen of the tallow corn.




DAVY'S SAFETY LAMP.         263
bine into a gas from the heat of the
flame; and this gas is called carburetted
hydrogen or inflammable air.
Q.  Why do COAL-MINES SO frequently EXPLODE?
A.  Because the carburetted hydrogen
gas (which is generated in these mines
by the coals) explodes, when a light is
incautiously introduced.
Q. How can miners SEE in the coal-pits if
they may never introduce a LIGHT?
A. Sir Humphrey Davy invented a
lantern for the use of miners, called " the
Safety Lamp," which may be used without danger.
Q.  Who was Sin HUMPHREY DAVY?
A. A very clever chemist, born in
Cornwall, 1778, and died in 1829.
Q. What kind of thing is the SAFETY-LAMP?
A.  A  kind of lantern, covered with a
fine gauze wire, instead of glass or horn.
Q. How does this fine GAUZE WIRE prevent an
EXPLOSION in the coal-mine?
A.  By preventing the flarle of the
lamp from  communicating with the inflammable gas of the mine.
N. B. The interstices of the gauze wire must not ex.
ceed the 7th of an inch in diameter.
Q. Why will not FLAME PASS THIROUGH vert
finc woire GAUZE?




264 CARBURETTED HYDROGEN GAS.
A. Because the metal wire is a very
rapid conductor of heat; and when the
flame (of gas burning in the lamp) reaches the wire gauze, so much iheat is conducted awoay by the tvire, that the flame is
extin guished.
Q.  Does the gas of the COAL-PIT get TIE-iOUGIT
{he wire gauze INTO thae LANTERN?
A.  Yes;  and  the  inflammable  gas
ignites, and  burns inside the latnp: As
soon as this is the case, the miner is in
danger, and should  wvithdllraw.
Q.  TWhy is the miner in DANGEr if the gas ig,
nites and burns in thle INSI)E of the safety lamp?
A.  Because the heat of the tburning
gas will soon destroy the wire gautze; and
then the flame (being free) will set fire
to the mine.
N. B. When the carburetted hydrogen gas takes fire
from the miner's candle, the miner sometilmes perislles in
the blast of the flame, and sometimes sultles s ffication from
the carbonic acid which is thus produced.




PHOSPHORUS.            265
PHOSPHIURETTED HYDROGEN
GAS.
CHAPTER XXIII.
Q. From what do the very OFFENSIVE EFFLUVIA of CHURCH-YAPDS arise?
A.  From  a gas called PUOSPHIURETTED  HYDROGEN; which  is phoslphorus
combined with hydrogen gas.
Q.  W4thal is rPIospIsorus?
A. A pale amber-colored substance,
resembling wax in appearance.  The
word is derived firon two Greek words,
which mean " to produce or carry light."
(OWS-0iPEl-). 
Q.  fIOW is PHOSPHORUS OBTAINED?
A. By heating- bones to a white
heat; by which means, the animal matter and charcoal are consumed, and a
substance called "phosphate of lime " is
left behind.
Q.  What is the PIOSPHATE OF LIME?
A.  Phosphorus united to oxygen and
lime; when sulphuric acid is added, and
the mixture heated, the lime is attracted
to the acid, and pure phosphorus remains.
If powdered charcoal be added, phosphorus may be
procured by distillation.
Q.  Of what is the ignitible part of LUCIFER
MATCHES made?
12




266  PHOSPHURETTED HYDROGEN GAS.
A. Of phosphorus: and above 250
thousand lbs. are used  every  year in
London  alone, merely for the manufacture of lu:.ifer matches.
Q.   Why'does a  PUTREFYING  dead  BODE
SMELL SO offensively?
A.  Because phosphuretted  hydrogen
gas always rises from putrefying' animal
substances.
The escape of ammonia and suiphuretted hlydrogen contributes also to this offensive effluvia.
Q.   What is the cause of the IGNIS FATUUS,
Jack o'Lanlern, or Vrill o'lhe l isp?
A.  This luminous appearance (which
haunts  meadows, bogs, and  marshes)
arises fiomn the gas of putrefyjin, anintal
and vegetable substances; especially from
decayinT  fish.
Q.   TIhat gases arise from these PUTREFYING
substances?
A.  Phosphuretted hydrogen fiom  putrefyinl) animctl substances: and
Carburetted hydrqogen, from  decaying
vegctable matters.  (See p. 262.)
Q.  Hlow is the gas of the ignis fatuus IGNITED
on bogs and meadows?
A.  Impure phosphuretted hydrogen
bursts spontaneously into flame, whenever
it mixes with air or pure oxygen gas.
Pure p)hosphuretted hydrogen will not ignite spontaneously-this spontaneous ignition is due to the presence of




IGNIS FATUUS.'267
a small quantity of the vapor of an exceedingly volatile liquid-compound of phosphorus with hydrogen, which is
occasionally prolduced with the gas itself.
If phosphorus be boiled with milk of lime, and the beak
of the retort be placed under water, bubbles of p)llosl)huretted hydrogen will rise successively through the water, and
(on reaching the surface) burst into flame.
Q.  TWhy does an ignis fatuus or IT'ill o'the
Wisp FLY fi'07  us when we RUN to MEET it?
A.  Because we produce a current of
air in front of ourselves, (when we run
towards the ignis fatuus) which drives the
light gas forewards.
Q.   IThy does an ignis fatuus'un AFTE ItUS
when we FLEEfrom it in afright?
A.  Because we produce a current of
air in the way we run, which attrlacts the
light gas in the same course; drawing it
after us as we run awayfromn  it.
Q.  Is not a kind of Jack o'Lanlern sometimes
produced by an INSECT?
A.  Yes; swarms of luminous insects
sometimes pass over a meadow, and
produce an appearance similar to tile
ignis fatuus.
Q.   M2lkay not many GHOST stories have arisen
from some igtis faluus lurking about churchi-yards?
A.  Perhaps  all the   ghost  stories
(which deserve  any  credit at all) have
arisen friom  the ignited  gas of churchyards, lurllking about the tombs; to wHhich
fear has added its own creations.




268               WIND.
WIND.
CHAPTER XXIV.
Q.  TIhat is WIND?
A.  Wind is air in motion.
Q.  TI/hat PUTS the air in motion, so as to produce wr.NTD?
A.  The principal caluses  are  the
variationts of heat and cold, produced by
the succession of day and night, and of
the four seasons.
Q.  TIhat efect has IJEAT upon the air?
A.  Heat rarefies the air and causes it
to expand.
Q.  l-Tow do you KNow that heat causes the air
to EXPAND?
A. Thus, if a bladder halffall of air
(tied tight round the neck) be laid before
a fire, the air will expand by the heat,
and fill the bladder.
Q.  }What EFFECT is produced upon air by
RAREFACTION?
A.  It is made lighter and  ascends
through colder strata; as a cork  (put at
the bottom of a basin of water) rises to
the surface.
Q.   Prove that rarefied air ASCENDS.
A.  When a boy sets fire to the cotton
or sponge of his balloon, the flame heats




AIR.               269
the air; which becomes so light, that it
ascends, and carries the balloon wil/h it.
Q. ]t1hat eftfct is produced upon AIR by COLD I
A.  It is condensed, or squeezed into
a smaller compass: in consequence of
which, it becomes heavier, and descends
towards the ground.
Q.  Prove that air is condensed by COLD.
A. Lay a bladder half full of air
before a firle, till it has become fully
inflated; if it be now removed fronl the
fire, the bladder will collapse again, because the air condenses into its former
bulk.
Q.  Wthat is meant by the bladder " COLLAPSING?1"
A.  The  skin  becoming  wrinkled,
shrivelled, and flabby; because there is
not sufficient air inside to fill it.
Q.  1How do you KNOW that CONDENSED air
will DESCEND?
A. Because a fire balloon falls to the
earth, so soon as the spirit in the cotton
is burnt out, and the air of the balloon
has become cold again.
Q. Does the SUN HEAT the AIR as it does the
SARTH?
A. No; the air is not heated by the
rays of the sun; because air (like water)
is a very bad conductor.




270                WIND.
Q.  Hlow is the AIR HEATED?
A. By convection, thus:-The stmr.
heats the earth, and the earth heats the
air restintg  utpon it; the air thus heated
rises, and is succeeded by other air, which
is heated in a similar way; till the whole
volume is wvarmned by " convective currents."
Q.  What is meant by':CONVECTIVE CURRENTS"
of hot air?
A.  Streams of air heated  by  the
earth, which  rise  tupwiards, and  carry
heat with4 then.  (See p. 226.)
Q.  Is the air in a ROOM in perpetual motion as
the air ABROAD is?
A. Yes; there are always twoo currents of air in the room we occupy; one
of hot air flowing oust of the room, and
another of cold air flowing into the room.
Q.  How do you KNOW that there are these TWO
currents of air in every occupied RooM?
A. If I hold a lighted candle near
the crevice at the top of the door, the
flame will be blown outovard (towvards
the hall); but if I hold the candle at the
bottom  of the door, the flame  will be
blown inwzards (into the ro7'0 ).
N. B. Thisis not the case if afire be in the room. When
a fire is lighted, an inward current is drawn through all
the crevices.
Q.   Why would the flame be blown OITTWARDS




CANDLE FLAME.            271
(towards the IIALL),'f a candle be held at the Tor of
the door?
A.  Because the air of the room beingheated, &c., ascends; and (floating  about
the upper part of the room) some of it
escapes throuLgh the crevice at the top of
the door, producing a current of air outwards (into the hall).
Q.  I Vhy/ would the fame be blown INWXARDS
(into the rooiL), if the candle be held at the BOTTOM
of the door?
A.  Because a partial vacuum is made
at the bottonm of the room, as soon as the
warm air of' the room has ascended to
the ceiling, or made its escape fi'om  the
room: and cold air fiom the hall rushes
under the door, to supply the void.
Q.  JT/rhal is meant by a "partial VACUUM being made at the BOTTOM of the noomI?"
A.  A  vacuum  means a place friom
which, the air has been taken: and a
"partial vacuum" means a place from
which a part' of the air has been taken
away.  Thus, when the air on the floor
ascends to the ceiling, a partial vacuum
is made on tle floor.
Q.  AnLd how is the vAcuuMfilled uP again?
A.  It is filled up by colder air, which
rushes (untlier the door, and tlhrough the,oindoto crevices) into the room.




272              WIND.
Q.  Give me an ILLUSTRATION.
A. If I dip a pail into a pond,ond
fill it with water, a hole (or vacuunm) is
made in thle pond as big as the pail; but
the moment I dratv the pail out, the hole
isfilled upl by the water around.
Q.  S/how how this illustration APPLIES.
A.  Thile  eated air, whllich ascends
from  the bottom of a room, is as much
taken away as the water in the pail;
and (as the void was instantly supplied
by other water in the pond) so the void of
air is suptplied by the air around.
Q.  PItOat is the CAUSE Of WIND?
A.  The suin heats the carth, and the
earth heats the air resting upon it; as
the warm air ascends, the void is filled
up by a rush of cold air to tile place; and
this r'us of air we call WIND.
Q.  Does the WIND ALWAYS blow?
A.  Yes; there is always somne motion
in the air; but the violence of the motion
is perpetually varying.
Q.  Does the rotation of thle earthl upon its axis
affect the motion of the air?
A. Yes, in two ways. 1st-As the
earth  moves round  its axis, the thir
moveable air is left somewhat behind'
and, therefbre, seems (to a stationary




VERT'ICAL RAYS.          273
object) to be blowing in the opposite direction to the earth's motion: and
2dly-As the earth revolves, different
portions of its surface are continually
passing under the vertical rays of the,sun.
Q.  TVhen are the rays of the sun called " VERTICAL RAYS?"
A.  Whllen the sun is in a direct line
above any place, his rays are said to be
" vertical " to that place.
Q.  illustrate the manner in which the earth's
surface passes unlder the vertical sun.
A. Stlppose the brass meridian of a
globe to represent the vertical rays of
the sun; as you turn the globe round,
different parts of it will pass under the
brass rim, in constant succession.
Q.  WZ?/ is it NOON-DAY to the place over which
the SUN is VE:rTICAL?
A. Because the sun is half-wnay between rising and setting to that place.
Q.  Shiotw how this ROTATION of t/he earth afects
th AIR.
A. If we suppose the brass meridian
to be the vertical sun, the whole column
of air bencath will be heated by the noonday rays; that part which the sun has
left, will become gradually colder and
colder; and that part to which the sun
129




274                WIND.
is approaching,  will grow   constantly
warmoer and warmZer.
Q.  Then there are THREE qualities of air about
this spot?
A. Yes; the air over the place, which
has passed the meridian, is cooling; the
air under the vertical sun is the /hottest;
and the air. which is over the place about
to pass under the meridian, is increasing
in heat.
See fig. on next page. The column A (which the sun
has passed) is cooling-B is under the vertical sun; and
C is inc?'easitg in heat.
Q.  How does this VARIETY in the HEAT Of AIR
produce WIND?
A.  The air always seeks to preserve
an equiilibriun: so cold air Inshes into
the voidl made by the upward current of
the trarrm air.
Q.  Wthy does not the wind ALWAYS BLOW
ONE way, follouowig the direction of the SUN?
A.  Because the direction of the wind
is subject to perpetual interruptions from
hills, and valleys, deserts, seas, &c.
Q.  Ifio0w can HILLS and MOUNTAINS ALTER the
course of the WIND?
A.  Suppose a wind (blowing from
the north) comes to a mountain; as it
cannot pass through it, it must either
rush back again, or fly off at one side, (as
a marble, wheen it strikes against a wall.)




MOUNTAINS-OCEAN.                27'5
Q.  Do MOUNTAINS afect the wind in any OTHER
way 
A.  Yes; many mountains are capped
with snow, and the warm  air is condensed,
when it comes in contact with them; but
so soon as the temperature of the wind is
changed, its  direction  may  be changed
also.  (See Fig.)
THE SUN.
Suppose A F C, to be three columns of air.  A, the column of air which is cooling down; B, the column to which
the sun is vertical; and C the column which is to be heated
next. In this case the cold air of A will rush towards B C;
because the air of B and C is hotter than A. But suppose
now C to be a snow-capped mountain: As the hot air of B
reaches C, it is chilled; and (being now colder than the air
bchind) it rushes back again towards A, instead of following the sun.
Q.  Iow  can the OCEAN affect the direction of
the WIND?
A.  When the ocean rolls beneath the
vertical sun, the water is not omade so hot
as the land; in consequence of which,
the general direction of the wind is directed from tracts of ocean towards tracts
of land.
Q.   Why is not the WATER of the sea made so




276               WIND.
HOT, by the vertical sun, as the surface of the
LAND?
A.  1st-Because the evaporation of
the sea is greater than that of' the land:
2dly-The  constant motion  of the
water prevents the increase of temperature at the surface: and
3dly-The rays of the sun strike into
the water; in consequence of whMich the
immediate surface is much less affected.
Q.  TT'hy does the EVArPORATION of the sea prevent its surface from being HIEATED by the vertical
sun?
A.  Because its heat is absorbed in the
generation of vapor and carried off into
the air.
Q.  Why does the MOTTON of the sea prevent its
surfacefifrom being HEATED by the vertical suin?
A. Because each portion r7olls alway,
as soon as it becomes heated, and is
succeeded by another; and this constant
motion pr-events the sufitcfce of the sea
from being mnore heated than the water
belowt the surface.
Q.  Do CLOUDS affect the WIND?
A.  Yes.  As passing clouds screen
the direct heat of the sun firom the earth,
they diminish the rarefaction of the air
also; and this is another cause why nei.




TRADE WINDS.            277
ther the strength nor direction of the
wind is unrifor':
Q.  Would the wind blow regularly from east
to west, if these OBSTRUCTIONS were REMovED?
A.  Without doubt.  If the whole
earth were covered with water the winds
would always follow the sun, and blow
uniformly in one direction.
Q.  Do winds EVER. blow REGULARLY?
A. Yes: in those parts of the world,
which present a large surface of water,
as in the Atlantic and Pacific Oceans.
Q.  Whfat are the winds, which blow over the
ATLANTIC and PACIFIC Oceans, called?
A.  They are called "Trade Winds."
Q.  IM/hy are they called " TRADE WINDS."
A. Because they are very convenient
to merchants, who have to cross the
ocean, inasmuch as they always blow
in one direction.
Q.  In what DIRECTION do the TRADE WINDS
blow?
A. That in the northern hemisphere
blows from  the north-east; that in the
southern hemisphere from the south-east.
Q.  Why do they not blow from  the FULL
NORTH and SOUTH?
A. Because currents of air flowing
fron the poles, give them an easterly direction.




'278               WIND.
This effict is due in some measure to the rotation of the
earth on its atis.
Q.  WThat is the cause of these currents of ait
fron tlhe POLES to the EQUATOR?
A.  The air about the equator constantly ascends, in consequence of being
rarefied by the heat of the sun: as the
hot equatorial air ascends, cold air from
the north and south flows towards the
equator, to restore the equilibrium.
Q.  Is there an UPPER as well as a LOWER
CURRENT iZ the atmosphere?
A. Yes; the uppver current of rarefied air is fronm  the equator to the poles;
where it is condensed-and then returns
again to the equator, forming the lowoer
current.
Q.  These LOWER CURRENTS (from the poles to
the equator) have an EASTERLY tendency.  Explain
the cause of this.
A. All the atmosphere revolves with
the earth; but when a current of air from
the poles flows towards the equator, it
comes to a part of the earth's surface
which  is moving faster than itself; in
consequence of which it is left behind,
and thus produces the effect of a current
moving in the opposite direction.
Thus, to a person in a carriage, the hedges and trees
seem to be running in an opposite direction.
As the circumference of the earth at the equator is




POLAR CURRENTS.                279
mtch tarBget, than the circumference of the earth at the
poles, the rcfore every spot of the earth's equatorial surface
must move nuch faster than the corresponding one at the
poles.
N. B. As the earth revolves on its axis from west to
east, therefore the air which is carried with it will seem
to blow from the west: As, however, the current of air from
the poles seems to blow in the opposite direction, it will
seem to blow friom the east (or to' be an easterly wind).
Q.   By what means are the north-east and
south-east TRADE WINDS produced?
A.  By a combination of the two motions of the polar currents: which  produces the intermediate directions of the
north-east and south-east.
Q.  Are BOTH these motions of thepolar currents
REAL?
A. No. The motion from the east
to west is only apparent. As the earth
revolves fiom  iwest to east. the air carried
with it will be a wrest wind; but the polar
currents  seem   to  blow  in  the  opposite
direction, merely because  they have not
acquired the same velocity.
Q.   Do trade winds blow from  the north-east
and south-east ALL the YEAR ROUND?
A.  Yes, in  the open  sea; that is, in
the Atlantic and Pacific Oceans, for about
300 each side of the equator.
Q.    LAIat do the north-easterl?/ and south-easterly trade  winds produce when they meet near the
equator?
A. A region of calms, in which thick




280                WIND.
foggy air prevails, with sudden showels
and thunder-storms.
Q.  Is this region of calms FIXED in its position?
A.  No; it shifts its place according
to the sun's distance, and  position  in
regard to the equatar: beinrg sometimes
entirely to the nlorth of the equator, and
occasionally reaching as far as 2~ south
of it.
Q.  Do the TRADE WINDS blow uniformly from
north-east and south-east in the IrNDIAN OCEANT 
A. No; nor yet in those parts of the
Atlantic and Pclcfic which vergre on the
continents.
Q.  How do the TRADE WINDS in the INDIAN
OCEAN blow?
A.  From  April to October a southwest wind prevails; but from October to
April, a norith-east.
Q.   What are these periodical currents of air
(which affect the neighborhood of the Arabian, In.
dian, and Chinese Seas) called?
A.  They are called MONSOONS.
Q.  lHow far do the limits of the MONSOONS extend?
A.  They  extend  from  the African
shore to the longritude of New  Guinea
and  are felt ngrithwvard as far as the
parallel of latitude, which crosses the
Loochoo Isles.




MONSOONS.              281
The Loochoo Isles are about 241 north latitude, and
130~ east longitude.
Q.  Why do not the trade winds it the INDIAN
OCEAN blow south-west from April to October?
A.  Because the air of Arabia, Persia,
India, and China, is so rarefied by the
enormous heat of' their summer sun,
that the cold air from  the south rushes
towards these nations, across the equator,
(during  these six months,) and produces
a SOUTH-WEST wind.
Q.  To what distance does this SOUTH-WEST
wind prevail?
A.  From 3~ south of the equator, to
the shores of the Arabian, Indian, and
Chinese Seas.
Q.  Why ldo the trade winds (in the INDIAN
OCEAN) blow norlh-east from October to April?
A.  Because the southern part of the
torrid zone is most heated, when the sun
has left the northern side of the equator
for the southern: and the cold air firom
the north (rushingc towards the southern
tropic) is diverted into the direction of
NORThI-EAST, where it continues for the
other six months of the year.
Q.  Are the monsoons as POWERFUL as thb
trade winds?
A. They are far mnore so, and very
often amount to violent gales.




282               WIND.
Q. 1V',y are the MONSOONS more USEFUL to tke
marzner than the fixed TRADE WINDS?
A.  Because the mariner is able to
avail himself of these periodic changes,
to go in one direction during one half of
the year, and to return in the opposite direction during the ot'ter half.
Q.  How is the chantge of the monsoons marked?
A.  By an interval of alternating calms
and storms.
Q.  When are the WINDS at the NORTII generally the HIG EST?
A. T'he winds in December and January are generally the highest. Those
in February and November the next;
and those in August and September are
the least boisterous.
Q.  Why are the winds at the North generally
HIGHEST in DECEMBER and JANUARY?
A.  Because the sun is furthest south
in those months; and (as the heat in
these northern regions rapidly decreases)
the contrast between our temperature
and that of the torrid zone is greater in
December and  January, than in  any
other two months throughout the year.
Q.  Why does this CONTRAST of heat increase
the VIOLENCE of the WIND?
A. Because the air always seeks to
preserve an equilibrizn; therefore the




THE GOODNESS OF GOD.        283
greater the contrast, the  more violent
will be the rush of air to equalize the
two volumes.
Q.  Why are the winds at the North generally
most PLACID during the moAths of SEPTEMBEP and
AUGUST?
A.  Because August and September
are the?warmest monthLs, when we approach nearest to the heat of the torrid
zone; therefore the air (to and friom the
equator) moves with less velocity in our
northern hemisphere in those'two months
than in any other.
Q. Show the GOODNESS and WISDOM of GOD inr
this constant tendency of air to equilibrium.
A. If the torrid zone were not tempered by cold air from the polar regions,
it iwould become so hot, that no human
being could endure it.  If (on the other
hand) the polar regions were never
warmed by hot air from the torrid zone,
they  would  soon become insuffelably
cold.
Q.  In u'hat OTHER way does the mingling of
the polar and equatorial atmosphere act BENEFICIALLY?
A.  In  the  equatorial regions, the
great abundance of vegetable life is productive of a very large amount of oxygen: In the colder regions, artificial fires




284              WIND.
and dense masses of animal life, produce
large quantities of carbonic acid: The
mingling of the polar and equatorial
atmosphere assists in supplying each of
these regions with the very gas in which
it would be otherwise delective.
Q.  How does the mingling of the POLAR an4
EQUATORIAL atmosphere serve to supply each r'egion
with the GAS it most requires?
A.  lThe plants of the EriUATORIAL regions require carbonic acid;-The animals  of the COLDER  regions  require
oxygen:-The currents of air from  the
Poles carry carbonic cacid to the equatorial plants; and the currents of air firom
the Epuator carry oxygren to the animals
which abound nearer the pI)oles.
Q.  Why/ are EAST wINDS in Europe, and
WEST WINDS in the United States, generally D tY?
A. Because they come over vast continents, and therefore absorb very little
water; and being thirsty, they readily
imbibe moisture from thle air and clouds,
and therefore bring dry weather.
\  Q.  Why is the NORTH WIND generally COLD?
A. Because it comes firom the polar
regions, over mountains of snow and
seas of ice.
Q.  Why are NonRT WINDS generally DRY and
bting?




NORTH AND SOUTH WINDS.   285
A. Because they come from colder
Legions, and bein(r woarmed by the heat
of our climate, absorb  noisture from
every thing they touch; in consequence
of which, they are both dry andpatrchQ.  Wchy are SOUTH WINDS generally WArM?
A.  Because they come from the torfid zone, where they are much heated.
Q.  W'hy do SOUTH WINDS often bring RAIN?
A.  Because, coming  from  the torrid
zone, they are much heated, and inmbibe
water vcry plentfiully, as they pass over
the Ocean.
Q.  How does this account for the RAINY character of SOUTH winds?
A. As soon as they reach a cold climate they are condensed, and can no
longoer hold all their vapor in suspension; in consequence of which, some of
it is deposited as rain.
Q.  Why are WEST rINDS in Europe, and
EAST W[NDS in the United States, generally RAINY?
A. Because they come over the
Atlantic  Ocean, and  are laden  with
vapor; if, thereforey they meet with the
least chill, some of the vapor is deposited
as rain.
Q.  Why is a fine CLEAR DAY sometimes ovEtw
CAST in a few minutes?




286              WIND.
A. Because some sudden change of
temperature has condensed the vapor of
the air into clouds.
Q.  Why are CLOUDS sometimes DISSIPATED very
suddenly?
A. Because some dry wind (blowing
over the clouds) imnbibes their moisture,
and carries it off in invisible vapor.
Q.  Why do SOUTH-EAST winds bring us RAIN?
A. Because they come from the torrid zone, and get laden with vapor in
their transit across the ocean. But when
they reach our colder climate, (being
condensed by the chill) some of the vapor is precipitated in rain.
Q.  Why do NORTH-WEST winds RARELY bring
RAIN.
A.  Because they come from a climate
colder than our ovwn, and their capacity
for imbibing vapor is increased, when
they reach a warmer climate; in consequence of which, north-west winds dry
the air, dispel the clouds, and promote
evaporation.
Q.  Why does WIND sometimes bring RAIN and
sometimes FINE weather?
A.  If the wind be colder than the
clouds, it will condense their vapor into
rain: But if the wind is warmer tltan




MARCH WINDS.            287
the clouds, it will dissolve them, and cause
them to disappear.
Q.  What is the UsE ovdry MARCH winds?
A.  They dry the soil, which is saturated with the floods of February, break
up the heavy clods, and fit the land for
the seed committed to it.
Q.  Why is it said, that " MARCH COMES IN
like a LION?"
A.  Because it comes in with bluster
ing iwinds, so essential to dry the soil,
lest it rot the seeds committed to it.
Q.  W7hy does " MARCH GO OUT like a LAMB?'
A. Because the water (evaporated
by the high winds) falls again in showers,
to fertilize the earth; and these constant
showers break the violence of the winds.
Q.  Why is it said, that " A bushel of MARCH
DUST is worth a king's ransom?"
A. Because it indicates that there
has been a continuance of dry weather;
and unless March be dry, the seed will
rot in the wet soil.
Q.  Why is it said, "A DRY, cold:MARCB
never BEGS BREAD?"
A.  Because the dry, cold twinds of
March prepare the soil for seeds; which
germinate and produce fruit in the
autumn.




88                 wNVID.
Q.  It is said, that "A WET MARCH makes a
SAD autumn."  Explain the reason of this.
A.  If.MVarch is wet, so  much seed
rots in tile ground, that the autumn crops
are spoiled.
Q.  It is said, that "M ARCH FLOwERS ma/ke
NO summer BOWERS."  Explain the reason of this.
A.  If the sprinog be very nmdild, vegetation gets too forward, and is pinched
by the nightly friosts, so as to produce
neither fruits nor flowers.
Q.  It is said, "A LATE SPRING makes a FRUITFUL YEAR.;' Explaig the reason of this.
A.  If the  vegetation  of spring be
backward, the fiosty nights will do no
harm; for the fruits and  flowers will
not put forth their tender shoots, till the
nighrlts become tog  warm t injure th/em.
Q.   Why is it said, that "APRIL SHOWERS
bring MAY FLOWERS?"
A.  Because  April showers  supply
the  principal  nourishment, on  which
seeds depend for their development.
Before seeds call germinate, three things are essential:Darkness, Hecat, and Moisture.
Q.  Does RAIN-WATER possess any fertilizing
properties, BESIDES that of mere MOISTURE?
A.  Yes;  rain-water  contains  an
abundance of carbonic acid, and a small
quantity of amnmo'nlia; to which much
of its fertilizing power may be attributed.




RAIN.                289
Ammonia is a compound of nitrogen and hydrogen.
Common hartshorn is only ammonia and water.
Q.  MW7!) is there MOnE rain Fr'OM SEPTEMBER
to MARCH, than fJon rot Tarch to Septeminer?
A.  Because the temperature of the
air is constantly  decreasing; on which
account, its capacity for holdming vapor is
on the decrease, and the vapor is precipitated as rain.
Q.  Whhat good purpose is efected under PRovIDENCE by this increase of rain i? AUTUMN and WINTER?
A. Because rain hastens the putrefaction of the fallen leaves; and this
makes the earth fertile.
Q.  WIly is there LESS rain FROMz MARCH to
SEPTEMBER, than from September to M]arch?
A.  Because the temperature of the
air is con.stantly increasing;  on which
account its capalcity for holdjbng vapor is
on the increase, and very little is precipitated as rain.
Q.  Why is the RISING SUN in summer accompanied with a BREEZE?
A. Because the heat of the rising
sun stops the radiation of heat from the
earth, and warnvs its surface.
Q.  HIow does this WARMTH produce a BREEzE?
A.  The  air (resting on the earth's
surface) being warmted by contact ascends,
13




290                WIND.
and colder air rushing in to fill up the
void, produces the mrrning breeze.
Q.   Trhy is there often an EVENING BREEZB
during the summer months?
A.  Because  the earth radiates heat
at sun4-st and the air is rapidly cooled
down  by  contact:  this condensation
causes a  mnotion in the air, called the
eveningr breeze.
Q.  ITVIy are TROPICAL ISLANDS subject to a
SEA BREEZE every MORNING: (i. e., a breeze blowing
from the sea to the land)?
A. Because solar rays are unable to
heat the surface of the sea, as they do
the earth; therefore, the air resting on the
sea is less heated than the air restinto on
the earth; and the colder sea air blows
inland to restore the equilibrium.
Q.   Why is a LAND BREEZE UNIIEALTHIIY?
A.  Because  it is frequently  laden
~with  exhalations from  putrefying  animal and vegetahbh substances.
Q.   W&hy is a SEA BREEZE fresh and HEALTHY?
A. Because it passes over the fresh
sea, and is not laden with noxious exhalations.
It is particularly healtky, therefore, to walk on the sea.
beach before ten o'clock in the morning; but unhealthy
after sun-set.
Q.  fJ/7y is there generally a fresh breeze fitom
the SEA during the summer and autumn MORNINGS?




SEA AND LAND BREEZES.   291
A.  Because land is more heated by
the sun, than the sea is; and the land air
becomes hotter than that over the sea;
in consequence of which, the cooler sea
air glides inland to restore the equilibrium.
Q. Why does a SEA BREEZE feel COOL 2
A. Because the sun cannot make the
surface of the sea so hot as the land;
therefore, the air which blows firom the
sea is cooler than the air of the land.
Q.  WTIhy are TROPICAL ISLANDS subject to a
LAND BREEZE every EVENING (i. e., a breeze blowing
from the lan7d towards the sea)?
A.  Because the surface of the land
cools clown faster (after sun-set) than
the surface of the sea: in consequence
of which, the air of the cold land is condensed-sinkls down-and spreads itself
into the warmer sea air-causing the
LAND BREEZE.
Q.  IWhy is the LAND BREEZE COOL?
A.  Because the surface of the land
is cooled at sun-set quicker than the surface of the sea; therefore, seamen feel
the air from the land to be chill.
Q.  Why is the TEMPERATURE of ISLANDS mtre
EQUABLE than that of CONTINENTS?
A.  Because the wtiner around the island  absorbs the extreme heat of sum



292               WIND.
mer; and gives out heat to initig'ate the
extreme cold of winter.
Q.  ISLANDS are WARMER in winter than conti.
Tents. E.xplaia the reason of this.
A.  Unless the sea be fJiozen (which
is rarely the case) it is warmer than the
fiozen land: and the warimth of the sea
air helps to mitioate the intense cold of
the land air.
Q.  Explain the cause of sea WAVES?
A.'The wind (acting on the surface
of the sea) piles up ridges of toater,
leaving  behind an indentation: as the
water on all sides rushes to fill up this
indentation, the disturbance spreads on
all sides, and billow rolls after billow.
Q. W7My does WIND generally.feel COLD?
A.  Because a constantly  changing
surface comes in contact with our body,
to draw off its heat.
Q.  Wh/y is a ROOM (even without a fire) geo
nerally wAR:lMER than the OPEN AIR?
A.  Because the air in a room  is not
subject to much change, and soon becomes
of the saime temperature as our skin,
when it no longrer feels cold.
Q.'Wrhy do we generally feel COLDER out-of.
doors than in-doors?
A. Because the air (which surrounds
us) is always changing; and as fast as




COOLING.             293
one portion of air has become warmer
by contact with our body, another coldei
portion surrounds us, to absorb more
heat.
Q.  How does BLOWING HOT FOOD make d
COOL?
A.  It causes the air (which  has
been heated by the food) to changce msore
rapidly, and give place to fresh cold air.
Q.  Why do ladies PAN THEMSELVES in hot
weather?
A.  Thatfiresh particles of air may be
brought in contact with their faces by
the action of the fan; and as every
fresh particle of air absorbs sorie heat
from  the  skin, this  constant chtange
makes them cool.
Q.  Does afan COOL the AIR?
A.  No; it makes the air hotter by
imparting to it the heat out of oUr face;
but it cools our face by transferring its
heat to the air.
Q.  HIow fast does wind travel 
A. A gentle breeze goes at about
the rate of 5 miles an hour. A hi-gh
wind from 20 to 60.  A hurricane from
80 to 100 miles an hour.
Q.  How is the VELOCITY of WINDS ascertaied?
A. By observing the velocity of the




294               WIND.
clouds; and by an instrument for the
purpose, called an Anemometer.
Pronounce An-e-mom'-e-ter. From two Greek words
se/,oo (wind) and pLeTroy (a measure). This terml is applied
more friequently to an instrument which measures the force
of wind.
Q.  flow is the VELOCITY of the CLOUDs ascertained?
A. By observing the speed of their
shadow  along  the  ground;  which  is
found (in a high wind) to vary from  20
to 60 miles an hour.
Q.  Why is there a strong DRAUGHT through
the KEYHOLE of a door?
A.  Because the air in the room  we
occupy is varmner than  the air in the
hall; therefore, the  air from  the  hall
rushes throZugh the keyhole in the room,
and causes a draught.
Q.  Why is there a strong DRAUGHT UNDER the
DOOR, and thzrough the crevice on each side?
A.  Because cold air rushes fromn the
hall, to  supply the  void in  the room,
caused by the escape of warm air up
the chimney, &c.
Q.  lVthy is there always a DRAUGHT through
the WINDOW crevices?
A.  Because the external air (being'colder than the air of the room we occu-,py) rushes through the window  crevices to supply the deficiency, caused by




DRAUGHT-VENTILATION.    295
the escape of warm  air up the chimney,
&c.
Q.  If you open the LOWER SASH of a window,
there is more DRAUGI1T than if you open the UPPER
sash. Explain the reason of this.
A.  If the  lowcvr sash be open, cold
external air will rush freely into the room
and  cause  a great draught inwrards;
But if the utpper sash be open, the hcated air of the roonm will rush out, and (of
course) there will be less dlraught inwards.
Q.  By which means is a noon better VENTILATED-By opening the upper or the lower sash?
A.  A  room  is better ventilated  by
opening the upjper sash; because the hot
vitiated air (which always ascends towards the ceilingc) can escape nmore easily.
Q.  By which means is a HOT ROOM more
quickly COOLED-B/y openi2ng the upper or the lower
sash?
A.  A hot room is cooled mtore quickly
by opening the lowver sash; because the
cold air can enter more freely at the
lower part of the room, than' at the uplttper.
Q.  WIhy does WIND DRY damp LINEN?
A. Because dry wind (like a dry
sponge) imbibes the particles of vapor
from the surface of the linen, as fast as
they are formed.




296            16AROM ETER.
Q.  Thlich is the HOTTEST PLACE in a ch~Src
shael, cr theatlre?
A. Thle gallery.
Q.  TVhy is the GALLERY of all public places
HOTTER than the LOWER parts of the building?
A. Because the heated air of the
building ascends; and  all the cold  air
(which can enter tllrough the doors and
windows) keeps to tlte floor, till it has become heated.
Q.  Why do PLANTS often grow out of WVALLS
ald TO\WERS?
A. Because the seed has been blown
there with  the  dust, by  the wind, or
dropped by some bird flying over.
BAROMETER.
CHAPTER XXV.
Q.  WThat is a BAROMETER 
A.  A weather-olass, or instrument to
measure the variations in the wCeighlt of the
air; by means of which variations, we
may judge what weather may be expected.
BIAROMETER is a compound of two Oreek words, By
(weight) and prTpoI (a mecasure).
Q.  Whkat is a THERMOMETER?




BAROMEIETER.              297
A.  An instrument to show  how  hot
or cold anything is.
THER MOMFTEn is a compound of two Greek words Oqp.
Fos (heat) and pErpov (11'asure).
Q.  Wthlat is the DIFFERENCE between a TIIER.
MOMETER and a BARGOMETER? 
A.  In a TIERMOMETER  the mercury
is sealed up jfi'on  the air; and  rises or
falls, as thle varying temperature of the
air expands or contracts it: but
In  a BAROMETER the mercury  is left
exposed (or open) to the air;*  and  rises
or falls, as the varying  wreight of the air
presses upon the open column.
Q.  If the mercury of the thermometer be SEALED
uP from the air, hour can the air AFFECT it?
A.'The heat of the air passes through
the glass tube into the mercury which
causes the metal to expand and rise in
the tube.
Q.   Why is the TUBE of a barometer left OPEN?
A.  That the air may press utponl it
freely; and, as this pressure varies, the
mercury rises orfalls in the tube.
The top of the tube must be a " vacuum;" otherwise
the pressure of the external air upon the lower part of the
column cannot affect the mercury.
Q.  iow can a barometer, which measures the
WEIGHT of air, be of service as a WEATHIER glass?
* At its lower extremity.
13*




238           BAROMETER.
A. Whcn air is moist, or filled with
vapor, it is lighter than usual; and the
column of mercury stands low:
When air is dry and free from vapor,
it is heavier than usual; and the mercury
stands high: Thus the barometer (by
showing the variations in the weighlt of
the air) indicates the  changes of the
weather also.
Q.  Why can you tell (by looking at a BAROMETER) what KIND of WEATHER it will be?
A. Because the mercury in the tube
rises and falls, as the air becomes heavier or lighter: and we can generally tell
by the weight of the air, what kind of
weather to expect.
Q.  Does the WEIGHT of the air VARY MTUCH 
A.  Yes; the  atmosphere varies as
much as one-tenth part more or less.
Q.  What USE is a BArOMETER. to sailors?
A.  It warns them  to regulate their
ghips, before squalls come on.
Q.  Howi can a BAROMETER warn SAILORS to
regulate their SHIPS?
A.  As it indicates when wvind, rain,
and stornm  are at hand, the sailor can
make his shiptrifn before they overtake
him.
Q.  Are there any RULES which can be deended
Mn?




BAROMETER.              299
A. Yes; there are ten special rules
to dlrct us how to know the changes
of wcatther, by marking the mercury of
a barometer.
Q.  Mentinn the 1ST SPECIAL RULE with regard
to the baromter?
A..  The barometer is highest of all
during a long frost; and  it generally
rises with a north-west wind.
Q.  Why is the barometer HIGHEST of all during
a long FROST?
A.  Because a lonog frost condenses the
air very greatly; and the more condensed
air is, the greatpr is its pressure on the
mercury of a barometer.
Q.  Why does the barometer generally RIsE
with NORTH-WES MWinds?
A. Because NORTH-WEST' winds make
the air both cold and dry: and  being
both condensed, and without vapor, it is
much heavier.
Q.  Mention the 2D SPECIAL RULE with regard
to the barometer?
A. The barometer is lowest of all
during a thdwt, which follows a longs frost:
and  it generally  falls with  SOUTH  or
EAST wind.
Q. Why does the barometer fall LOWEST of all
t the BREAKING UP of a long FROST?
A. 1st-Because the air (which had




300           BAROMETER.
been much dried by the frost) absorbs
the moisture of the fresh warm1  current
of wind from the south or south-west:
and
2dly —The air (which had been much
condensed by the frost) is suddenly expanded by the warm  wind, which is
introduced.
Q.  Why does the barometer fall very low with
SOUTH and EAST winds?
A.  Because souTH and EAST winds
come heavily laden wvith vrp9r; and vaporized air is lighter than dry air.
Q. wThat effect has WIND on the mercury?
A.  The barometer is high, when the
wind blows between the  VEST and the
NORTH; but it is lo10, when the wind
blows between the SOUTH and the EAST.
Q.  WilY do these winds affect the mercury of a
barometer?
A. Because the pressure of the air is
increased by cold winds, and diminished
by wcarmn ones.
Q.  Why is the pressure of air INCREASED with
cold windsfrom the NORTH? 
A.  Because the air contracts, when
it is cooled by winds fiom the north and
east, and warmer air flows in friom  all
sides to fill up the vacuum; in conse



BAROMETER.             01
quence of which, its volume is increased,
and the barometer rises.
Q.  Why is the PRESSURE of a);r DIMINISHED
by warm winds from the SOUTII?
A.  Because the air ascends when it is
heated by south winds, and flows away
in all directions; in consequence of
whicha, its volume is diminished, and the.lercu'y falls.
Q.   4i/hat is the 3D SPECIAL RULE with regard
to the barometer?
A.  While the barometer stands above
30, the aiir must be very dry, or very
cold, or perhaps both —and no rain may
be expected.
Q.  Tlhy will there be NO RAIN if thle AIR be
very DRY?
A.  Because dry air will absorb mnoisture, and not part with it in rain.
Q.  TV7ty will there be NO RAIN if the AIR be
very COLD?
A.  Because it is so much condensed,
that it has already parted with as much
moisture as it can spare.
Q.  What is the 4TII SPECIAL RULE wilth regard
to the barometer?
A.  When the barometer stands very
/loz  indeed, there will never be much
rain; although a fine day will seldom
occur at such times.




302            BAROMETER.
Q.  Wfhat kind of WEATHER is there likely to
be, wher tlhe barometer is UNUSUALLY LOW?
A.  S'lort heavy showers, with sudden
squall. oj'wvind from the west.
Q.  tIVy will there be VERY LITTLE RAIN, if
the baromt)eter is UNUSUALLY LOW?
A.  Because  the  air must be very
warr,, or very moist, or perhaps both.
Q.  TVhy will there be little or no rain, if the
AIR be ver(y WARI M?
A.  3Because warnm  air has a tendency to imbibe nwr'e moisture and not to
part with what it has.
Q.'IThy will there be little or no rain, if the
air be MOIST and the barometer very LOW?
A. Because rain will never fall (even
thouXgh the air be saturated), till cold air
has -been introduced to condense the vapor: And, as soon as cold air has been
introduced, the barometer will rise instantly.
Q.  Name the 5TH SPECIAL RULE with regard
to the bar-ometer?
A.  In summer-time (after a long continuance of fair weather) the barometer
will fall graduaily for 2 or 3 days before
rain comes: But if the fall of the mer.
cury is very sudden, a thunder-storar  may
be expected.
Q.  What is the 6Tn SPECIAL RULE wZil regard
to the barometer?




BAROMETER.              303
A.  When the sky is cloudless, and
seems to promise fair weather —if the
barometer is lozv, the face of the sky will
soon be suddenly overcast.
Q. Wat"hat is the 7TH SPECIAL RULE With regard
to the barometer?
A. Dark dense clouds will pass over
without rain, when  the  barometer is
high,; but if the barol:neter be lwo, it
will often rain without any appearance of
clouds.
Q.  WTThat is the 8TH SPECIAL RULE with regard
to the barometer?
A. Trrhe higher the barometer, the
greater the probability of fair weather.
Q.  W7iy is the barometer HIGH in FINE weather?
A.  Because the air in fine Nweather
contains v3ry little vapor.  The drcier the
air, the higher does the mercury of the
barometer rise.
Q.  TlVhat is the 9TH SPECIAL RULE with regard
to the barometer?
A. When the mercury is in a risilng
state, fine weather is at hand; but, when
the mercury is in a sinking state, foul
weather is near.
Q.  Wh"by does the mercury RISE at the approach
Of FINE weather?
A.  Because the air is becoming more




304             BAROMETER.
dry; and, therefore, its priessure is in.
creased.
Q.  TWhy does the mercury SINK at the approach
of FOUL weather?
A.  Because  the air is laden wDith vapor or  diturbed by winzd.
Q.   IVhy does vArPrJ in the air make the mercury sNK?
A.  Because vaporized air is lighter
thanl  dr'y air;  and its pressure on the
barometer less.
Q.  ITWhat is the 1 OTI  SPECIAL RULE with regard to the baroneter?
A.  If (in firosty weather) it begins to
snow?, the barometer oenerally rises to
30;  where it remains,  so long as the
snow  continues to fall: If, after this, the
weather clears up, you may expect very
severe cold.
Q.  IHow can you know if the MEIRCURY of the
barometer is RISING? 
A.  When  the top of the column is
convex (i. e., higher ini the middle than at
the sides), the mercury is in a risitgc state.
Q.  I-ow can you'tell if the MErCUarY of the
barometer is FALLING?
A.  When  tlle top of the column is
concave (i. e., hollow in the middle), the
mercury is in afallirng state.
Q.   Why is the mercury CONVEX when ii is
RISING'




BAROMETER.             305
A. Because the parts of the nmercury
in contact with the tube are delayed by
the glass; in consequence of wliich, the
middle part rises faster than the sides;
and the surface is CONVEX.
Q.  T/VWhy is the mercury CONCAVE uhen, it is
FALLING?
A.  Because the parts of the mercury
in contact with the tube are delayed by
capillary attraction; in consequence of
which, the middle part sinks fasters than
the sides: and the surface is CONCAVE.
Q.  What effect does a THUNDER-STORnl produce
on the weather?
A.  It is generally preceded by hot
weather, and followed by cold and showery weather.
Q.  WT/hat efect does a SUDDEN CHANGE of temperaiure produce on the weather?
A.  A great and sudden change (either firom hot to cold, or from cold to
hot) is generally followed by rain wvithin
24 hours.
Q.   WAVy is a suddenr CHANGE from HOT to
COLD followed by RAIN?
A.  Because cold condenses the air;
and some of its vapor is given off in
rain.
Q.  W7iy is a sudden CIIANGE from COLr to
noT followed by RAIN?




3BO6           BAROMETER.
A. Because the air is quickly saturated with  moisture: but when night
comes on, and chills the temperature,
some of the abundant moisture is given
off in rain.
Q.  Why is the air quickly SATURATED with
MOISTURE, uwhen HEAT rapidly succeeds to COLD?
A.  Because the evaporation (which
was checked by the cold) is carried on
very rapidly, in consequence of the diminislted pressure of the air.
N. B. The less the pressure of the air, the more rapid the
evaporation of moisture will be.
Q.  lW~hen does the barometer VARY MOST.
A.  In winter-time.
Q.  Wly does the barometer vary MORtE in
WINTER, than ill SUMMEn-time?
A. Because the difference of temperature between the torrid and temperate
zones is much greater in winter than in
summer: and produces a greater disturbance in the state of the air.
Q. icWhen does the barometer VARY LEAST?
A.  In summer-time.
Q.  Tlhy does the barometer vary LESS in SUMMrER tMan in WINTEn-time?
A. Because the temperature of the
torrid and temperate zones in summer
is so  actrly equal, that its state is not
musch disturbed by interchanlre of cur,
rents.




BAROMETER.              307
Q.  1Ttve HEAT and COLD any elect on the ba'ometer?
A.  No, not of themselves; but be.
cause cold weather is generally either
dry, or routgh  with  north-west winds,
therefore the mercury rises in cold weather: And  because warm   weather is
often  n      oist, or fanned  by  south-east
winds, therefore. the  mercury sinks in
warm  weathler.
Q.  1V/Iy is the mercury of a barometer LOWVER
in the TORIr)D than in the FRIGID zone?
A.  Because the warm  air of the torrid zone contains much more va)7or than
the condensed  air of the frigid  zone;
and the imoister the air, the less is its
pressure.
Q.  In wChat MONTHS is the barometer HIGHEST?
A.  In  May  and  August; then  in
June, Marlcl, September, and April.
Q.  In what MONTHS is the barometer LOWEST?
A.  In November and February; then
in October, July, December, arind January.
Q.  I7ly is there LESS wet from MAncH to
AUGUST thanl there is from August to ianrch?
A.  Because the heat is conzstntly increasingr   and the capacity of air to abl
sorb and retain moisture increases likewise.




308              BAROMETER.
Q.   T'Vh is there MORE wet from AUGUST tt
MIARCH thatn fiom MIarch to Augusl?
A.  Because  the  heat is  constantly
dccreasiclf; and  the capacity  of air to
retain  mnoisture decreases also; so that
altholah  it often  rains, yet the air is
alwavs on the point of saturation.
Q.   IV/.y does the mercury of a baroleter RJSE
in a FROST?
A.   Because frost condl31ses the air;
and coldensed air is heavier than rarefled air.
Q.  AWhy does the mercury of a barometer FALL
in a THAW'?
A. Because the air is filled with
vap)or.
Q.  TIhat does a SUDDEN rise or fall of the barometer inldicate?
A.  If the rise be  sudden, fine weather will not continue longr:
If tile fitll be sudden, foul weather
will not continue long.
Q.   Whlat sort of weather may wc expect, if the
barometer is very FLUCTUATING?
A.  If' the mercury fluctuates much,
the weather will be very cit ucable and
unsettled.
THE FALL OF TTiE BAROMETER.
In very h/It vweather, the fall of the mercury denotes
thundcr. Otllherwise, the sudden falling of the barometer
denotes high wind.




BAROMETER -SNOW.                    309
In frost?/ weather, the fall of the barometer denotte tha7w,
If wet wenttler happens soon after the fall of the ba.
rometcr, expect i1but little of it.
n wael wealther, if the barometer falls, expect much wet.
In fir wveatlier. if the barometer falls and renmails low.
expect much wet in a few days, and probably wind.
N. B. The barl)meter sinks lowest of all for wind and
rain together; next to that for wind, (except it be an east
or north-east windl.)
THE RISE OF TTF:.BAROMETER.
In winter, the rise of the barometer presages frost.
In fiosly weather, the rise of the barometer presage
snoV.
If fair weather happens soon after the rise of the ba.
rometer, exlpect but little of it.
In wet weatller, if the mercury rises high and remains
so, expect continled fine wealther in a day or two.
In wet weatlher, if the mercury rises suddenly very high,
fine weather will not last long.
N. B. The barometer rises highest of all for north and
westwinds; for all ollter winds it sinks.
THE BAROMTF-P.R UNSETTLED.
If the motion of the mercury be u4nsettled, expect unsettled weather.
If it stamjl at " MUCII RAIN " and rise to " CANGEABLE,r"
expectfair wealhcer tf short continuance.
If it stanlrld at " PAIR" and fall to " cHANEAEnr,,"   expect
foul weather.
N. B. Its motion lupwards indicates the approach of
fine weather; its motion downwards indicates the approach
of foul weather.
SNOW. IIAIL. RAIN.
C HAPTER XXVI.
Q.   TTM7at is sxow?
A.      hile  condensed vapor of the  air
frozen, and precipitated  to the earth.




310                 SNOW.
Q.   What is the CAUSE of S.NOV?
A.  Whlen the air is neaily saturated
with vapor, and condensed by a curtrent
of air bdl)o1o freezing point, some of the
vapor is condensed, and firozen into
snow.
A few years ago, some fishermen (-who wintered at
Nova Zenblla) after they had been shut tu) ill a hut for
several days, opledl the wuindow, and the (ol external air
rushing in, instantly condensed the air of the hut, and its
vapor fill on the floor in a shower of snoWu.
Q.   ITViy does sNowfall in WI~NTER ti1me?
A.  Because  the sun's ravs are too
obliqtue to heat the surface of the earth;
and (as the earth has no heat to radiate
into the air) the air is very cold.
Q.   WTrhat is the cause of SLEET? 
A.  When  flakes of snoxv (in  their
descent) pass through a bed of air above
freezilg point, they partially melt; and
fall to the earth as half-melted snow, or
sleet.
Q. WThat is the USE of SNOW?
A.  To keep the earth wzarm, and to
noujrisht it.
Q.  Does snow keep the EARTH WARM?
A.  Yes, because it is a very bad conr
ductor; in consequence of wlhich, when
the earth is covered with snow, its temnperature very rarely descenlds below




VSE OF SNOW.           311
freezing p)oint, even when the air is 15
or 20 degrees colder.
Q.  WaH iS SNOW a BAD CONDUCTOR of heat
and cold?
A.  Because air is confined and entangled among the crystals; alld air is
a very bad conductor: When, therefore,
the earth is covered with snow, it cannot
throw off its heat by radiation.
Q.  Tell me the words of the PSALMIST (cX1Vii.
16) respecting snow; and explain what he means?
A. The Psalmist says-" The Lord
giveth snow like wool;" and he means,
not only that snow is as white as wool,
but that it is also as warm as wool.
Q.  TVhy is WOOL WARM?
A. Because air is entangled among
the fibres of the wool; and air is a very
bad conductor.
Q.  Why is SNOW WARM?
A.  Because air is entangled among
the crystals of the snow; and air is a
very bad conductor.
Q.  Why does SNOW NOURISH the earth?
A. Because it supplies moisture con
taining carbonic acid; which penetrates
slowly into the soil, and insinuates itself
through every clod, ridge, and furrow.
Q.  Why is there No sNow in YUMmIER time?




312          SNOW-HAIL.
A. Because the heat of the earth melts
it in its descent, and prevents it from
reachingr the surface of the earth.
Q.  Why are some MOUNTAINS ALWAYS COVER
ED with SNOW?
A.  1st-Because the air on a high
mountain is more rarefied; and rarefied
air retains mdch heat in a latent state:
and
2dly —Mountain-tops are not surrounded by earth, to radiate heat into the air;
and, therefore, the snow  is not melted
in its descent, but falls on the mountain,
and lies there.
Q.  WVhy is SNOW WHIITE?
A. Because it is formed of an infinite
number of very  minute crystals and
prisms, which reflect all the colors of the
rays of light from different points; and
these colors, uniting before they meet
the eye, cause snow to appear white.
The same answer applies to salt, loaf-sugar, &c. (S
p 3;72.)
Q. WhTat is HAIL?
A.  Rain, which  has passed in its
descent throutgh some cold bed of air, and
has been frozen into drops of ice.
Q.  TVhat makes ONE bed of air COLDER thanS
another?




HAIL-RAIN.              313
A. It is frequently caused by electricity unequally distributed in the air.
Q.  Why is HAIL frequently accompanied with
TIIUNDER and, LIGHTNING?
A. 1st-Because the congelation of
tvatcr into hail disturbs the electricity of
the air: and
2dly —The friction (produced by the
fall of hail) excites it still more.
Q.  IYhy does HAIL fall generally in SUMMEl
and AUTUMN?
A.  1 st-Because  the air is more
highly electrified in summer and autumn
than in winter and spring: and
2dly-The vapors in summer and
autumn (being rarefied) ascend to more
elevated regions, which are colder than
those nearer the earth.
Q.  TVhat TWO things are essential to cause
IAIL 2
A.  Two strata of clouds having opposite electricities, and tiwo currents of twind.
The lower cloud (being negative) is the
one Iprecil)itated in hail.
Q.  What is RAIN 
A The vapor of the clouds or air
condensed, and precipitated to the earth.
Q.  When is the vapor of the azr or clouds
PRECIPITATED in hail, rain, or snow?
14




814              RAIN.
A.  When the air is saturated zwith va.
popt, and a cold current condenses it; it
is then no longer able to hold all its
vapor in solution, and some of it falls as
rain.
Q.  T'hy does RAIN fall in DROPS?
A. Because the vapory particles in
their descent attract each other; and
those which are sufficiently near unite,
and form into drops.
Q.  Why does not the COLD of NIGHT ALWAYS
cause rain?
A. Because the air is not always near
saturation; and unless this be the case,
it will be able to hold its vapor in solution, even after it is condensed by the
chilly night.
Q.  Why does a PASSING CLOUD often drop
LRAIN?
A. Because the cloud (travelling
about on the wind) comes into contact
with sonzetlinog that chills it; and its vapor being condensed, falls to the earth as
rain.
Q.  Why are RAIN-DROPS sometimes much
LARGER than at OTHER tizv's?
A.  Because the rain-cloud is floating
near the earth; when this is the case,
the drops are large, because such a




RAIN-WATER.               315
cloud is much more dense than one more
elevated.
The size of the rain-drop is also increased, according to
the rapidity with which the vapors are condensed.
Q.  Does not WIND sometimes INCREASE the
SIZE of razn-dirops?
A. Yes; by blowing two or more
drops into one.
Q.   Why do CLOUDS FALL in RAINY weather?
A.  lst-Because they are heavy with
abundant vapor: and
2dly-The density of the air being
diminished, is less able to buoy the clouds
up.
Q.  HIow do you KNOW that the DgNSITY of die
air is DIMINISHED in RATNY weather?
A.  Because  the  mercury  of a barometer f/lls.
Q.   T4fhy is RAIN-WATER, more FERTILIZING
thzni PUMP-WATER? 
A. 1st-Because it contains more
carbonic acid: and
2dly —It contains also a small quantity of annmmonia, with which it supplies
the young plants.
It is probable that the ammonia of rain-water is merely
that which escapes from putrefying animal matters, beaten
back by the force of the shower.
Q.   Why does RAIN PURIFY the AIR?
A.  1st-Because  it beats down the




316              RAIN.
noxi(tUs exhalations collected in the air,
anl dissolves them:
2dly —It mixes the air of the tupper
regions with that of the loiwer regions:
and
3dly —It washes the earth, and sets in
motion the stacnant contents of sewers
and ditches.
Q.  Wrhy are MOUNTAINOUS countries more
RAINY thanflat ones?
A.  Because thle air (striking against
the sides of the mountains) is carlriod up
the inclined plane, and brourght in contact
with the cold air of the hioher regions:
in consequence of whicli, its vapor is
condensed, and deposited in rain.
Q.  W7My does a SPONG7, SWELL when it U
WETTED?
A.  Because the water penetrates the
pores of the sponge by capillary attraction, and drives the particles fur therj fSom
each other; in consequence of which, the
bulk of the sponge is greatly incr'eased.
Q.  Why do FIDDLE-STRINGS SNAP in WET
weather?
A. Because the moisture of the air
(penetrating  the  strin() causes it to
swell; and (as the cord thickens) its
tension is inc eased, and the strinc snaps.




MOISTURE              317
Q.  Why does PAPER PUCKER whe.n it is wETTED?
A. Because the moisture (penetrating
the paper) drives its particles fairtlhe
apart; and (as the moisture is absorbed
unequally by the paper) some parts are
more enlarged  than  others; in consequence of which, the paper blisters or
puckers.
Q.  Wt/hy do the weather-toys (called cAPUCHINs)
lift the cowl over the figures in wet wealher, and
remove it in dry?
A.  Because the cowl of the cap'utchin
is attached to a piece of cat-gut in such a
manner, that when the cat-gut is shortened by moisture, it pulls the cowl up;
but in dry weather the string is lodsened,
and the cowl falls down by its own
weight.
Q.  Il another weather-toy the MAN comes out
in WET weather, and the LADY in FIN W: —Why is
this?
A.  Because the two figures are attached to a piece of cat-gut in such a
manner, that when the cat-gut is sho2tened by moisture, it pulls the mann out;
but when it is loose, the wooran falls out
by her own weight.
Q.  Why are WET STOCKINGS DIFFICULT id
PULL ON?




318               RAIN.
A. Because the moisture penetrates
the threads of the stockings, and causes
them  to shrink inz size.
Q.  In which PART of the DAY does the MOAT
RAIN fall?
A.  More rain falls by nigl1t than by
day; because the cold night condeetses
the air, and diminishes its capacity for
holding vapor in solution.
Q.  Does more rain fall in saMsmaE or in WIN'
TER?
A.  There are more rainy days from
September to March; but heavier rains
between March and September.
Q.  W'hy are there MORE RAINY DAYS from
September to lMarch than fi'onI Mlarch to September?
A.  Because the temperature of the
air is constantly decreasing, and its capacity for llolding vapor decreases also;
in consequence of which, it is frequently
obliged to part with some of its vapor
in rain.
Q.  In what PART of the WORLD does RAIN fall
MOST ABUNDANTLY?
A.  Near the equator; and the quantity of rain decreases, as we approach the
poles.
Be it remembered that there are fewer rainy days,
although more rain actually falls during the wet season
of the equator, than falls in 12 months at any other pIart
of the globe.




PUMP-WATER.              319
WAT ER.
CHAPTER XXVII.
Q.  Of what is WATER composed?
A. Of two gases, oxygen and hydro.
gen.
In 91bs. of water-8 are oxygen, and 1 is hydrogen.
Q.   WkThy is WATER FLUID?
A. Because its particles are kept
separate by latent heat: When a cer.
tain quantity of this latent heat is driven
out, tvater becomes solid, and is called
ice.
By increasing its latent heat, the particles of water are
again subdivided into invisible steam.
Q.   Why is PUMP-WATER called " HARD water?"
A. Because it is laden with foreign
matters, and will not readily dissolve
substances immerse I in it.
Q.  WThat makes P'IMP-WATER HARD?
A.  When it filters thrQugh tile earth,
it becomes impregnated with sulphate of
lihlc, and many other impurities from the
earths and minerals with which it comes
in contact.
Q.  WlThat is the cause of MINERAL SPRINGS?
A.  WhV-en water trickles through the
ground, it dissolves some of the substances with  which it conies in contact; if




320              WATER.
these substances are metallic, the water
will partake of their mineral character.
Some water is imbued with lime; some with sail, &c., &c.
Q.  Why is it diicult to WASH oar HANDS
clean with HARD water?
A.  Because the soda of the soap combines with the sulphuric acid of the hard
water —and the oil of the soap with the
lime —and floats in flakes on the top of
the water.
N. B. Sulphate of lime consists of sulphuric acid and
lime.
Q.  Why is it difficult to wash in SALT WATER?
A.  Because it contains rnuriotic acid;
and the soda of soap combines with the
muriatic acid of the salt vwater, and produces a cloudiness.
Q.  What is the cause of PETRIFACTIONS?
A. While water rolls underground,
its impurities are held in solution by the
presence of carbonic acid: but when
the stream reaches the open air, its carbonic acid escapes, and these impurities
are precipitated on various substances
lying in tile course of the stream.
These impurities are especially carbonate of lime and
Iron.
Q.  Why does a BLACK HAT turn RED a' th4
IEA;SIDE?
A.  Because the mnuriatic acid of the




8OA P-RAIN-WATER.           321
sea water disturbs the gallic acid of tho
black dye, and turns it red.
Q. Of whitt is SOAP made?
A. Of kelp (or the ashes of sea-weed
dried and burnt in a pit) mixed with oil
or fat.
YELLOW SOAP is made of whale oil, soda, and resin.
SOFT SOAP is made of oil and potash. HIARD SOAP, of oil
and soda.
Q.'Why does WATER CLEAN dirty LINEN?
A. Because it dissolves the stains, as
it would dissolve salt.
Q. Why does SOAP greatly INCREASE the cleansing power of water?
A. Because many stains are of a
greasy nature; and soap has the power
of uniting wvith greasy matters, and renderin( them soluble in water.
Q.  Why is RAIN-WATER SOFT?
A.  Because  it is not impregnated
with earths and minerals.
Q.  WhLy is it MORE EASY to WASH with sorr
water, than with HARD?
A. Because soft water unites freely
with soap, and dissolves it; instead of decomposing it, as hard water does.
Q.  Why do WOOD ASHES make HARD Wated
SOFT?
A. 1st-Because the carbonic acid
of wood ashes combines with the sulphate
14*




322             WATER.
of limle in the hard water, and converts
it into chalk: and
2dly-Wood ashes convert some of
the soluble salts of water into insoluble,
and throw them down as a sediment; in
consequence of which, the water remains
more pure.
Q.  Why has RAIN-WATER such an UNPLEASANT
SMELL, when it is collected in a rain-water tub or
tank?
A.  Because it is impregnated with
decomposed  organic  matters, washed
fi'cn roofs, trees, or the casks in which
it is collected.
Q.  Why does WATERk MELT SUGAR? 
A. Because vex minute particles of
water insinuate themselves into the
pores of the sugar, by capillary attraction; and force the crystals apart from
each other.
Q.  Why does WATER MELT SALT?
A. Because very minute particles
of water insinuate themselves into the
pores of the salt, by capillary attraction;
and force the crystals apart from each
other.
Q.  Why does melted SUGAR or SALT g;ve a
FLAVOR to water?
A. Because the sugar or salt (being
disunited into very minute pieces)floats




SEA-WATER -SrAGNANT WATER. 323
about the water, and mixes with every
part.
Q.  Why does HIOT water melt sugar and salt
QUICKER than COLD water?
A. Because the heat (entering the
pores of the sugar or salt) opens a passage for the water.
Q. Why is SEA-WATER brackish?
A.  1st-Because the sea  contains
mines of salt at the bottom of its bed:
2dly-It is impregnated with bituminous matter, which is brackish: and
3dly-It contains many putrid. substances of a brackish nature.
Q.  MTAhy is NOT RAIN-WATER SALT, although
most of it is evaporated from the SEA?
A.  Because salt will not evaporate;
and therefore when sea-water is turned
into vapor, its salt is left behind.
Q.  Why does STAGNANT water PUTREFY?
A. Because leaves, plants, insects,
&c., are decomposed in it.
Q.  Why is STAGNANT water full of WORMS,
EELS, 4C.?
A. Because numberless insects lay
their etggs in the leaves and plants floating on the surface; these eggs are soon
hatched, and produce swarms of worms,
eels, and insects.




324             WATER.
Q.  Wly is FLOWING water FREE from thes
IMPURITIES?
A.  1st-Because the motion of running water preventsfermentation:
2dly-It dissolves the putrid stzbstances which happen to fall into it: and
3dly —It casts on the bankc (by its
current) such substances as it cannot
dissolve.
Q.  M'Thy does RUNNINGC water OSCILLATE and
WHIRL in its current?
A.  1st-Because it impinges against
its banks, and is perpetually  diverted
from its forward motion: and
2dly-Because the centre of a river
flows fastert than its sides.
Q.  91(yJtdo the SIDES of a river flow more
TARDILM. tkal its CENTRE?
A.  Because they rub  against the
banks, and are delayed in their current
by t his l'iction.
Q.  1W7iy does SOAPY water BUBBLE?
A.  Because soap makes the water te,
nacious; anti prevents the bubbles from
bursting as soon as they are formed.
Q.  W'hy.will not water bubble WITHOUT SOAP?
A. Because it is not tenacious enough
to hold together the bubbles that are
forimed.




ICE.               325
Q. tWhen SOAP-BUBBLES are blown friom a pipe
why do they ASCEND?
A.  Becaulse they are filled?with lwarm
breath, which is lighter than air.
IC E.
CHAPTER  XXVIII.
Q.  What is iCE 
A.  FROZEN WATER.  When the air
is reduced to 32 decrees of heat, water
will no longer remain in a fluid state.
Q.  TWhy is SOLID ICE LIGHTER than WATERm?
A.  Because water expands by freezing; and as the bulk is increased, the
gravity must be less.
Nine cubic inches of water become ten when frozen.
Q.  WAy do EIWERS BREAK in a FROSTY NIGHT?
A.  Because the water in them freez.
es; and (expanding, by frost) bursts the
ewers to make room  for its increased
volume.
Q.  Why does it not expand UPWARDS (likd
boiling water), and RUN OVER?
A.  Because  the  surface is frozen
first; and the fiozen surface acts as a
plugt,, which is more difficult to  burst
than the earthen ewer itself.




326                 ICE.
Q.   hizy do TILES, STONES, and ROCKS Oflea
SPLIT in winter?
A. Because the moisture in thenm
freezes; and (expanding by frost) splits
the solid mass.
Q.  Int winter-time, FOOT-MARKS and WHEELRUTS are often covered with an icy NET-WORK,
through the interstices of which the soil is clearly
seen: — WTiy does the wuaterfreeze in NET-WORK?
A. Because it freezes first at the
sides of the foot-prints: other crystals
gradually shoot across, and would cover
the whole surface, if the earth did not
absorb the water before it had time to
freeze.
Q.  In winter-time, these FOOT-MARKS  and
WHEEL-RUTS are sometimes covered with a perfect
SHEET of ice, and not an icy net-work: —Why is
TtIlS?
A.  Because the air is colder and the
earth harder than in the former case, in
consequence of which, the entire surface
of the foot-print is frozen over before the
earth has had time to absorb the water.
Q.  Why is not the ice SOLID in these ruts? —
WHY is there only a very thin FILMI or NET-WORK Of
ice?
A.  Because the earth absorbs most of
the water, and leaves only the icy film
behind.




EXPANSION OF'ArATER.             327
Q.   WMiy do WATER-PIPES frequently rURST in
I Vosl r weIather?
A. Because the water in theinfreezes; and  (expanding by friost) bursts the
pipes  to  make  room   for its  increased
volume.
Q.  Does not water expand by HEAT as well as
by COLD?
A. Yes; it expands as soon as it is
more than 42 degrees, till it boils; after
which time, it flies off inl steam.
Freezing water, 32~0.       2120, Boiling water.
Here A B measures the bulk of a portion of water at
42 degrees.
It goes on increasing in bulk to C D, when it boils.
It also goes on increasing in bulk to E F, when it freezes.
Q.   AVHEN does WATER begin to EXPAND from
cold?
A.  When it is reduced to 42 degrees.
Water is wisely ordained by God to be
an  exception  to  a very  general rule-it
contra;cts till it is reduced to 42 degrees,
and then it expands till itfreezes.
The genleral rule is this-That cold condenses and contracts the volume of nearly everything; but water is not
cofntracted by cold after it freezes, (which it does at 320).




328                ICE.
Q.  WHY does water expand when it freezes?
A.  Becatuse it is converted into solid
crystals which do not fit so closely as particles of water do.
Q.  WIh/Ay is the BOTTOM of a river NEVER FROZEN?
A. Because water ascends to the
surface, so soon as it becomnes colder
than 42 degrees; and (if it freezes)floats
there till it is melted.
Q.  Stoww the WISDOM of GOD in this wondeful
exception to a general law.
A.  If ice were heavier ithan water, it
would sinlc; and a river would soon become a solid block of ice, which could
never be dissolved.
The general rule is —that all substances become ilavi'r
from condensation; but ice is lighter than water.
Q.  WThy does not the ICE on the SURFACE of a
river CHI LL the water BENEATI and make it fireze?
A.  lst-Because water is a very bad
condtctor, and is heated or chilled  by
CONVECTION only:
2dly-If the ice on the surface were
to comlmunicate its coldnzes3 to the water
beneath, the water beneath would communicate its heat to the ice, and the ice
would instantly melt: and
3dly-The ice on the surface acts as
a shiehl, to prevent the  cold air from




FROZEN RIVERS.           329
penetratinoW throlughr  tie river, to freeze
the water below the surface.
Q.  WMy does WATER FREEZE at the SURFACE
first?
A.  Because the surface is in contact
with the air, and the air carries awvay its
heat.
Q.  IWhy does the coat of ice grow THICKER and
THICKER if the frost CONTINUES 2
A. Because the heat of the water
(immediately below  the frozern surface)
passes throaugh the pores of the ice into
the cold air.
Q.  TVhy are not WHOLE RIVERS FROZEN
(layer by layer), till they become solid ice
A. Because water is so slotw a conductor, that our frosts never continue
long enough to convert a whole river into a solid mass of ice.
Q.  IbWhy does not RUNNING water freeze so
FAST as STILL water?
A. 1st-Because the motion of the
current disturbs the crystals, and prevents,
their forming' into a continuous surface:::
and
2dly-The heat of the under surface
is communicated to the upper surface by
the rolling of the water.
Q.  Wthen RUNNING water is FROZrN whJy is
ghe ICE generally very ROUGH?




330                ICE.
A. Because little flakes of ice are
first formed and carried dotwn tile stream,
till they meet some obstacle to stop) them;
other flakes of ice  (impinging,  against
them) are arrested in like manner; and
the edges of the different flakes overlapping each other, make the swuface rouogh.
Q.  WAhy do SOME parts of a RIVER FREEZE
LESS than OTHERS?
A. Because springs issue from the
bottom; and (as they bubble upwards)
thawv the ice, or make it thin.
Q.  When persons FALL into a RIVER in wintertime why does the WATER feel remarkably WARM?
A.  Because the frosty air is at least
10 or 12 degrees colder than the water is.
The water below the surface is at least 420; but the
air 32~, or even less.
Q.  TVh]y is SHALLOW%  water FROZEN more
QUICKLY than DEEP ualter?
A.  Because the whole volaune of water
must be cooled to 42 decrees, before the
sttufice cain be frozen: and it takes a
longer tiame to cool down a deep bed of
water than a shallow one.
Q.  I7Thj is SEA-WATER RARELY FROZEN?
A.  lst —Because the mass of zoater
is so great, that it requires a very long
time to cool the whole volume down to
42 degrees:




FREEZING.            331
2dly —Tle ebb anrd flowD of the sea interfere with the cooling influence of the
air: and
3dly —Salt water never freezes till the
surface is cooled down 25 degrees below
freezing, point.
Q.  Why do some LAKES RARELY (if ever)
FREEZE?
A.  1st-Because they are very deep:
and
2dly —Because their water is supplied
by springs, which bubble from the bottom.
Q.  W'hy does the DEPTH of water RETAtD its
FREEZING?
A.  Because the whole volume of water
must be reduced to 42 degrees, before
the surface woill freeze: and the deeper
the water, the longier it will be before
the whole volume is thus reduced.
Q.  WTVhy do SPRINGS at the bottom of a lake
PREVENT its FREEZING? 
A. Because they keep continually
sending forth frc'sh water, which  prevents the lake friom  being reduced  to
the necessary degree of coldness.
Q.  It is COLDER in a THAWv', than in a FROST.
Explain the reason of this.
A.  When fiozen water is thawed, it
absorbs heat from  the air, &c., to melt




332                ICE.
the ice; in consequence of which, the
heat of the air is greatly reduced.
Q.  It is WARlMER in a FROST than in a THAW.
Explain the reasons of this.
A.  When water f'reczes, it gives out
latent heat, in order that it may be converted into solidl ice; and, as much heat
is liberated from the water to the atmosphere, the air feels zvarnier.
Q.  SALT DISSOLVES ICE. Explain the reason
of this.
A.  Water freezes  at 32~, but salt
and water will not freeze till the air is
25 degrees colder; if, therefore, salt be
added to frozen water, it dissolves it.
Unless the thermometer stands below 70~.
Q.  WTill any thinr DnrIssoLvE ICE besides SALT?
A.  Yes; any acid, such as sulphuric
acid, nitric acid, &c.
Q.  W7ny is a mixture of SALT and SNow cold.
er than SNOW itself?
A.  Because salt dissolves the crystals
of snowv into a fluid: And whenever a
solid is converted into a fuid, heat is absorbed, and the cold Inade more intense.
Q.  IWhy does FROST make the EARTII CRACK?
A.  Because the water absorbed by
the earth in warmn weather, expanding
by the firost, thrusts the particles of




FROST.              333
earth apart from each other, and leaves
a chink or crack between.
Q.  Show the WISDOM of GOD in this arrangement.
A.  These cracks in the earth let in
air, dew, rain, and many gases favorable
to vegetation.
Q.  WIttLy does the EARTH CRUMBLE in SPrING?
A.  Because the ice of the clods dissolves; and the particles of earth (which
had been thrust apart by the frost) being
left zunsuppor'ted, tulnble into minute parts,
because their cement of ice is dissolved.
Q.  Why does MORTAR CRUMBLE away in
FROST?
A.  Because it was not dried in the
warnm  weathier; therefore its moisture
freezes, expand(s, and thrusts the particles of the mortar away fi'om each other;
but as soon as the fiost goes the iwater
condenses, and leaves the mortar full of
cracks and chinks.
Q.   Whty does STUCCO PEEL from a WALL in
FROSTY weather?
A.  Because the stucco was not dried
i;z the earnz weather; therefore its moisturefireezcs, exrpands, and thrusts its particles away from the wall; but, as soon
as the water condenses again by the




334               ICE.
thaw, the stucco (being unsupported)
falls by its owRn wzeight.
Q.  TFhy cannot BRICKLAYERS and PLASTERERS
work in FrOSTY weather?
A. Because frost expands mortar,
and causes the bricks and plaster to
start from their position.
Q.  Why do BRICKLAYERS COVER their worA
with STRAW in spring and autumn?
A.  Because straw  is a non-conductor; and prevents the mortar of their
new work from freezing, during the cold
nights of spring and autumn.
Q.  Why are WATER PIPES often covered with
STRAW in winter-time?
A.  Because straw (being a non-conductor) prevents the tWater of the pipes
fiomn freezing. and the pipes fron bursting.
Q.  W'Vi are delicate TREES covered with STRAW
in WINTER?
A. Because straw (being a non-conductor) prevents the sap of the tree from
being frozen.
Q.  Can WATER be FKOZEN in any way BE.
SIDES byfrosty weather?
A.  Yes; in very many ways.  For
example-a bottle of water wrapped in
cotton, and frequently wcttcd iwith ether,
will soon freeze.




FREEZING  MIXTURES.               335
Q.   W/hy w0ould WATER FREEZE if the bottle
were kept constantly wetled with ETHER?
A.  Because evaporation would carry
off the heat of the water, and reduce it
to the freezing point.
Q.   WMhy does ETHER freeze under the RECEIVER of an AIR-PUMP, when the air is exhausted?
A.  Because   evaporation   is   very
greatly increased  by the diminution  of
atmoaspheric pressure; and the ether
freezes by evaporation.
FREEZING MIXTURES.
1. If nitre be dissolved in water, the heat of the liquid
will be reduced 16 degrees.
2. If 5 oz. of nitre, and 5 of sal-ammoniac (both finely
powdered) be dissolved in 19 oz. of water, the heat of the
liquid will be reduced 40 degrees.
3. If 3lbs. of snow be added to 1lb. of salt, the mixture
will fall to 00 (or 32 degrees below fireezing point).
The two following are the coldest mixtures yet known1. Mix 31bs. of muriate of lime with llb. of snow.
2. Mix 5lbs. of diluted sulphuric acid with 4lbs. of snow.
Q.   Why is it more easy to SWIM ill the SEA
than in a RIVER?
A.  Because  the  specific  gravity  of
salt water is greater than that of fresh;
and, therefore, it buoys up  the swimmer
better.
Q.   How do cooks ascertain if their BBRINE be
SALT ENOUGH for pickling?
A.  They put an egg  into  their brine.
If the egg sinks, the  brine  is not strong
enough; if the ego floats, it is.




336              SWIMMINU.
Q.   T'Vhy  will an EGG SINK, if the brine be NOT
STRONG enougtrh for pickling?
A.  Because an egfog will be the heaviwr: but if as much  salt be  added  as
the water can dissolve, an egg will be
liglhter than the strong brine, and consequently float on the surface.
Q.  WHIY will an EGG FLOAT in strong BRINE
and not in water?
A. Because the specific gravity of
salt and?water is greater than  that of
water only.
Q.   Why do persons SINK in water when they
are UNSKILFUL S\VIMMERS? 
A.  Because  they  struggle  to  keep
their head out of walter.
Q.  Explain how this is.
A.  When  the  head  is thrown  back
boldly into the water, the mouth is kept
above the surface, and  the  swimmer is
able to breathe:
But when  the head  is kept above the
su~rface of' the water, the chlln and mouth
sink beneath it, and  the swimmer is suffocated.
This may be illustrated thus:-If a piece of wood be
of such specific gravity, that only two square inches can
float out of water; it is mnanifest, that if two olther inches
are raised out, the two former inches must be plunged in.
The body (in floating) resenllies this piece of' woodIf two square inches of the face float out of the water, the
swimmer can breathe; but if part of the back and crown




SWIMMING.               337
of the head be forcibly raised above the surface, a proportional qlantity of the face must be plunged it; and the
mouth becomles covered.
Q.   ItWhy can QUADRUPEDS swim MOnE EASILY
than MAN?
A.  lst-Because the trunk of quadrupeds is lightter than water; and this is
the greatest part of them: and
2dly-The position of a beast (when
swimmingir) is a natural one.
Q.  W'hy! is it MORE DIFFICULT for a MAN to
swim than for a BEAST?
A.  lst-Because his body is more
heavy in proportion than that of a beast:
and
2dly-The position and muscular action of a mnan (when swimminig) differ
greatly from his ordinary habits; but
beasts swim in their ordinary position.
Q.   Whrhy can FAT men swIM more EASILY than
SPARE men?
A.  Becausefat is lighter than waouter;
and the fatter a man is, the more buoyant will he be.
Q.  hIow are FISIIES able to ASCEND to the sunFACE of water?
A.  Fishes have an air-bladder near
the  abdomen;  when  this bladder  is
filled wzith air the fish increases in size,
and (being lighter) ascends through the
water to its surface.
15




338               LIGHT.
Q.  flHow are fishes able to DIvE in a minute tf
tei BOTTOIMT of a stream?
A.  They e.vpel the air from their airbladder; in consequence of which, their
size is diminished, and they sink instantly.
LIGHT.
CHAPTER XXIX.
Q.  TTWhat is LIGHT 2
A. Rapid undulations of a fluid called
ether, made sensible to the eye by striking on the optic nerve.
See p. 51.
Q.  Tlow FAST does LTGHT TRAVEL?
A.  Light travels so fast, that it would
go eight times round the earth while a
person counts " ONE."
Q.  Does ALL light travel equally fast?
A.  Yes; the light of the sun-the
light of a candle-or the  light from
houses, trees, and fields.
Q.  itrhere does the LIGHT of HOUSES) TREES,
and FIELDS, come from?
A.  The light of the sun (or of some
lamp or candle) is reflected fi'omn their
surfaces.




REFLECTION OF LIGHT.          339
Q.  Why are sOME surfaces BRILT,LIANT (like
glass and steel), and OTHErS DULL, like lead?
A.  Those surfaces which reflct the
most light, are the most brillia,-t; and
those which (tbsorb lirght are dall.
Q.  Wfrhat is meant by REFLECTING LIGHIT?
A.  Throwing the rays of lihllt back
again from  the surface on which they
fall.
Q.  Tjrhat is meant by ABsonRBIN  LTGIIT?
A.  Retaining  the  rays of lig)ht on
the surface on which they fall; in consequence of which, their presence is not
made sensible by reflection.
Q.  XWhy can a THOUSAND personas SEE the
SAME OBJECT at t]he same time?
A. Because it throws off firom its
surface an infinite numbler of rays  in
all directions; and one person sees one
portion of these rays, and another person
another.
Q.  Why is the EYE PAINED by a SUDEN light?
A. Because the nerve of the eye is
burdened wlith rays before the pupil has
had time to contract.
Q.  VWhy does it give us r, if a CANDLE be
brought suddenly towards oar BE: at nig lt lime?
A. Because the pupil of the eye dirates very much in the dark, in order to
admit more rays.   When, therefore, a




340               LIGHT.
candle is brought suddenly before us, the
enlarged pupils overiload the optic nerves
waith rays, which causes pain.
Q.  Why CAN we BEAR the candle-light after a
few moments?
A.  Because the pupils contract again
almost instantly; and adjust themselves
to the qluantity of lig ht which falls upon
them.
Q.  h/7y can wue SEE NOTIHING, when we leave
a WELL-LIGIITED room, and go into the DARKER
ROAD Or STREET 2
A.  Because the pupil (which  contracted in the bri(llt room) does not dilate
instantaneousl/y; and the contracted pupil is not able to collect rays enough
from the darker road or street to enable
us to see objects before us.
Q.  Why do we SEE BETTERI when we get USED
to the DARK?
A. Because the pupil dilates again,
and allows more rays to pass throu-gh
its aperture; in consequence of which,
we see more distinctly.
Q.  If we look at the SUN for a few moments,
why do all OTHE R things appear DAIRK?
A. Because the pupil of the eye becomes so imuch contracted by lookinc at
the sun, that it is too small to collect sufficient rays from other objects to evnable




VISION.              341
us  to  distinguish  their colors.   (See
"' Accidental colors;" pp. 375, 376.)
Q.  If we watch a bright FIrE for afew moments,
why does the ROOM seem DARK?
A. Because the pupil of the eye becomes so much contr'acted by lookinll at
the fire, that it is too snall to collect sufficient rays fromn the objects around to
enable us to distinguish their colors.
Q.  Why can we see the rorEOPE  COLOrS of
every object again, after afeuw minutes?
A. Because the pupil dilates again
and acconrmmodates itself to the light
around.
Q.  W/-hy can TIGERS, CATS, and owLS, see in
the DARK?
A. Because they have the power of
enlargin, the pupil of their eyes so as to
collect several scattered rays of lighlt;
in consequence of which, they can see
distinctly when it is not light enough for
us to see any thing at all.
Q.   Whiy do CATS and OWLS SLEEP almost all
DAY?
A. Because the pupil of their eyes is
very broad, and daylight fatigues them;
so they close their eyes for relief.
Q.   Trhy do CATS keep WINKING, when they sil
before a FIRE?
A. Because the pupil of their eye is




1342              LIGHIT.
very broad, and the lighlt of the fire is
painful; so they keep shutting their eyes
to relieve the sensation of too much ligrht.
Q.   Why do TIGERS, CATS, OWLS, 4C., PROWL
by NIGHIT.for prey?
A.  Because they sleep all day when
the  strong  lighlt would  be painful to
them; and as they can see clearly in the
dark, they prowl then for prey.
Q.  TTrhy do GLow-wonMS glisten by NIGHT
only?
A.  Because  the light of day is so
stron.  that it eclipses the feeble light of
a glow-worm; in consequence of which,
glow-worms are invisible by day.
Q.   Why can we NOT see the STARS in the DAYTIME?
A.  Because the light of day is so
powerful that it cclvipses thefeeble light of
tile stars: in consequence of which, they
are invisible by day.
Q.   TAVhy can  we see the STARS even at MIID-bAY,
from the botlom of a deep WELL?
A.  Because the light of the stars is
not overpowered by the rays of the sun,
which are lost in the numerous reflections whlich they underg'o in the well.
The rays of the sun will enter the well very obliquely
whercas, many stars will shine directlly over the well. See
pp. 348, 349.




TIHE EYES.               343
Q.   T7iat is the usE of TWO EYES, since they
yresent only/ one image of any object?
A.  To increase the licrht-or to take
in  more ratys of light from  tile  object
looked  at, in order that it may appear
more listiltct.
Q.   TVrhy do we NOT see things DOUBLE, with
TWO EYES?
A. lst-Because the axis of both eyes
is turncd to one object;  and, therefore,
the samie imlplessiorz is made on the retina of each eye: and
2dly-Because the nerves (whlich receive tile impression) have one point of
union before they reach the brain.
This is not altogether satisfactory, altllhough it is the
explanation igenrally given. The phenomenon p)robably
is rather pIsyhological than material.
Q.   Itrh/y do we SEE OURSELVES in a GLASS 2
A.  Because the rays of liight friomn
our face stl'ike agcainst the sufface of the
glass, and  (instead of being  absorbed)
are re/lcctcd, or sent back agrain to our
eye.
Q.   TTIr/y are the rays of light REFLECTED by
a MIRROR?
A.  Bccause they cannot pass throtugh
the in]lxnclet'able netal with  Vllich the
back of tile glass is covered; so  they
rebounld back, just as a marble xvould do,
if it were tlhrown against a wvall.




344                  LIGHT.
Q     Mrien a mcarble is rolledl towards a wall
what is the path THROUGH WIIIC[ IT RUNS called?
A.   Thle line of INCIDENCE.
Q.   TI/hen a marble REl;OUNDS back again,
what is the palh it THEN describes c(lled?
A.   Tile line of REFLECTION.
See fignra below. If AB be the line of incidence, then
BC is the line of reflection; and vice versa.
Q.   1V}hen the light of our face,goes TO the
GLASS, what is the path  througb which it goes
CALLED?
A.   Thle line of incidence.
Q.   Ilrhen the light of our face is r'eflected BACK
again. from the mirror, what is this iRETURNIlNG path
called?
A.  The line of re7fectto,.
Q.   T'Ihat is the ANGLE of incidence?
A.  Tr'le  angfle  between  tile  line  of
incidence arid the perpendlicitldr.
Q.   ITrhal is the ANGLE of re/leclion)?
A.  The  angle  betweenl  tlle  line  of
reflection  and  the perpendicular.   (See
ig. )
S.8             4




REFLECTION.                 345
Let SS be anS surface, PB a perpendicular to it.-If a
marble were thlrown from A to B, and bounded back to
C; then ABP would be called the angle of iTncidence, and
CBP the angle ot'frfection.
Q.   IVhy does our reflection in a mirror seem
to APPROACHI US) as we walk TOWAnrDS it; and to
RLETIRE FPOM US, as WE retire?
A.  Because the  lines and  ang,fles of
incidcncc  are  always equal to  the  lines
and  tincles of r eflection; in consequence
of which, tile inmag, e wvill always seem
to be as far belhind the mirror as the real
object is before it.
o     Oa                      F t
h         I-[              _1)         F
Suppose A to be a mirror —CA, EA and DA, FA, the
lines of ineilMece; then GA, KA and lhA, LA, are the
lines of redflction. When the arrow is at CD, its image
will applal alt G11, because line CA=GA, and line DA=
IIA; anldl also tlle an-le CAB=angle GAB, and angle
DAB=IIAB. Fol a similar reason, if the arrow were at
EF, the minage  w ould scem to be at KL.
Q.   I7tty can a man see his IWITOLE PERSON
reflecled i7 a LITTLE MIRROR, not 6 inches in length?
A.  Because the  lines and  angeles of
incidence are always equal to  the  lines
and angi nles of?eflection; in consequence
of wllich, his imnage will seem  to  be as'! ~~




346                   LIGHT.
far behind  the  mirror  as  his  person  is
before it.
Take the last figure-CD  is much larger than the mirror A; but the head of the arrow C is reflected obliquely
behind the mirror to G; and the barb D al)l)lars at I[.Why? Becaluse line CA=GA, and line D)A= =1I,It; also t!e
angle CAB =angle GAB, and angle DAB=1lAB.
Q.   1T7?.y does the IMAGE of anzy object in WA.
TER always appear INVEnTED?
A.   Because  the  angles  of incidence
are always equal to the a,nrgles (f rejtection.
A
--      ________.- A-,,
Here the,sirow-head A strikes the water at F, and is
reflected to D':red the barb B strikes the water at E, and
is refl:cted to C.
If a spectator stands at G, he will see the reflected lines
CE and DF l1'oduced as far as G.
It is very plain, that A (the more clckvated object) will
strike the water, and be' projected firom it more perpendicularly than the point B; and, thereforc, the image will
seem inverted.  See p. 345.
Q.   IVthen we see our nEFLECTION in WATER,
why do we seem to STAND On our                   E,:A,?
A.   Because  the  angles  of  incidence




GLASS AS A REFLECTOR.            347
are always eq al to the angles of reflection.
Suppose our head to be at A, and our feet at B; then
the shadow of our head will be seen at D, and the shadow
of our feet at C. (S&e figure on p. 346.)
Q.   Why do WINDOWS seem to BLAZE at SUNRISE and SUN-SET?
A. Because glass is a good reflector
of light; and the rays of the sun (striking against the window-glass) are reflected, or thrown back.
Q.   V7tLy do NOT windows reflect the NOON-DAY
rays also?
A.  They do, but the reflection is not
seen.
Q.  TWhy is the reflection of the RISING and,
SETTING sun seen in the uwindow, and NOT that of
the NOON-DAY sun?
A. Because the rays of the noon-day
sun enter the glass too obliquely for their
reflection to be seen.
Sun near noon.
Sun near the horium
V~~~~~~~~~a




348                 LIGHT.
In the preceding cut, AB represents a ray of thle noonday sun striking the window at B; its reflection will be at C.
But DB (a ray of the rising or setting sun) will be re.
flected to E (the eye of the spectator.)
Q.   Why can we not see the REFLECTION of the
SUN in a WELL, during the day-time?
A.  Because  the rays of the SUN fall
so  obliquely  that they  never  reach  the
surface of the water at all, but strike
against the brick sides.
THE SUN.
33J'
Let BDEC be the well, and DE the water.
The ray AB strikes against the brick-work inside the
wall; and
The ray AC strikes against the brick-work outside the
well.
None will ever touch the water DE.
Q.   Why are STARS REFLECTED in a WELL
although the sun is NOT?
A.  Because the rays of those STARS,
which pass nearly over-head, will not fall




REFLECTION  ON WATER.             349
so obliquely into the well as the rays of
the sun.
THE MOON OR A STAR.
D          i
Here the star's rays AB, AC, both strike the water DE,
md are reflected by it.
Q.   On a lake of water, the MOON seems to make
a PATH of light towards the eye qf the spectator, while
all the REST of the lake seems DAtLr-WIIY is this?
A. Because the lake is in deep shadowo; and many rays which would be
eclipsed by the broad light of day become visible.
The same path of light may be discerned in the day-time,
when a cloud passes over the sun.
Q.  In a sheet of water at noon, the sun appears
to shine upon only oNfE spot, and all the REST of the
water seems DARK-WVIIY is this?
A. Because the rays fall at various
degrees of obliquity on the water, and




350               LIGHT.
are reflected at similar angles; but as
only those  which  meet the eye of the
spectator are visible, all the water will
appear dark except that one spot.
C//3
Here, of the rays SA, SB, and SC, only the ray SC
meets the eye of the spectator D.
The spot C, therefore, will appear luminous to the spec.
tator D, but no other spot of the water ABC.
Q.  TWihy are MORE STARS visible from a MOUNTAIN than from a PLAIN?
A. Because they have less air to pass
through.  As air absorbs and diminishes
light; therefore, the higher we ascend,
the less light will be absorbed.
Q.  Why do the SUN and MOON seem LARGER
at their RISING and SET'INOG than at any other
time?
A.  Because the arch of the sky (in
which the sun and mnoon are seen) is




SUN AT HORIZON.               351
further distant at the horizon than it is
over-head.
lv:;!' ~~
/i
Let IMMI be the orbit of the sun or moon.
Let BD be the arch of the sky, in which the sun and
mnoon are seen by us.
It wsill be seen from the figure, that the sun or moon at
the horizon will appear much larger, because CD is longer
than CB.
The Phenomenon referred to on p. 350, (called the horizontal Sun anld MIoon), has perplexed philosophers to the
present hour. The solution given is not altogether satisfactory-Sir J. Herschell says, "The dilated size of the
sun or moon, when seen near the horizon, has nothing to
do with refraction. It is an illusion of the jdbgmet, arising from the terrestrial objects interposed, or placed in
comparison with them. Actual measurenlent with a proper instrument corrects our error, without, however, dis.
pelling our illusion-the whole is owing to the effect of
parallax."




352              LTGHT.
Q    Why can we NOT SEE into the STtrErT Mo
road, whena CANDLES are LIGITED?
A.  1st-Because glass is a reflector,
and throws the candle-lighllt back into the
roonm acrain: and
2dly-'rhe pupil of the eye (having
become contracted by  the lihrlt of the
room) is too small to collect rays enough
ftom  the dark street to enable us to see
into it.
Q.  TWhy do we often see the FIRE REFLECTED
in our parlor WINDOW in winter-time?
A.  Because glass is a good reflector;
and the rlays of the fire (striking against
the window-glass) are reflected back into
the roonm again.
Q.   Why do we often see the image of our CANDLES in the window, while we are sitting in our
parlor?
A. Because the rays of the candle
(striking against the glass) are reflected
back into the roonz; and the darker the
night, the clearer the reflection.
Q.  WrH  is this reflection more clear, if the
external AIR be DARK?
A. Because the reflection is not
eclipsed by the bri(ghter rays of the sun
striking on the other side of the wtndgiw.
Q.  If the SHADOW qf an object be thrown on a
wall-the CLOSER the object is held to the CANDLE.
the LARGER will be its SHADOW.  Why is this?




EFFECTS OF DISTANCE.              353
A.  Because the rays of light diverge
(from  the flame of a candle) inc strainght
lines like lines drawn fiom  the centre of
a circle.,,.
Here the arrow A held close to the candle, will cast the
shadow BF on a wall; while the same arrow held at C
would cast only the little shadow DE.
Q.   HWhen we enter a long AVENUE of TREES,
WHY does the avenue seem to get NARnROWER and
narrower till the two sides appear to TMEI'T?
A.  Because the further thle trees are
off, the more acute wvill be the angle that
any opposite two make with our eye..e |.. —':?:?~. Gc
Here the width between the trees A and B will seem to
be as great as the line AB:




351                  LIGHT.
But the width between the trees C and D will seem to
be no mete than EF.
Q.   In a long', strazght STREET) WHY do the
houses on the opposite sides seem to APPROACH NEiARER
together as they are more DISTANT?
A.  Because  the   more  distant  the
houses are the more acute twill be the angle which any opposite two make with
our eye.
Thus in the last figure,
If A and B were two houses at the top of the street, the
street would seem to be as wide as the line AB:
And if C and D were two houses at the bottom of the
street, the street there would seem to be no wider than
EF.
Q.   In an AVENUE, WHY do the TREES seem to
be SMALLER as their distance increases?
A.  Because the farther the trees are
off, the more acute will be the angle made
by their perpendicular height with our
eye.
Here t ftep.....   A
Here the first tree AB will appear the height cf the
line AB; but the last tree CD will appear only as high as
the line EF.
Q.   In a long, straight STREET, WIIY do the
houses seem to be SMALLER and smaller, the FURTHER
they are OFF?
A.  Because the further any house is
off, the more acute wrill be the angle made
by its perpendicular height with our eye.




PERPENDICULAR  HEIGHT.             355
Thus in the last figure,
If AB be a house at the top of the street, its perpendicWlar height will be that of the line AB.
If CD be a house at the bottom of the street, its perpen.
dicular height will appear to be that of EF.
Q.   Why does a man on the TOP of a MOUNTAIN, or church spire, seem to be no BIGGER than a
cnow? 
A.  Because  the  aigle made  in  our
eye by the perpendicular height of the
man at that distance, is no bigger than
that made by a crow  close by.
Let AB be a man on a distant mountain, or spire, and
CD a crow close by:
The man will appear only as high as the line CD, which
is the height of the crow.
Q.   Why does the MOON appear to us so much
LARGER than the STAns, though, infact, it is agreal
deal SMALLER?
A.  Because  the  moon  is very much
nearer to us than any of the stars..3:::::::::
~~ r u"~'




356                   LIGHT.
Let AB represent a fixed star, and CD the moon.
AB, though much the larger body, will appear no big.
ger than EF; whereas the moon (C1)) will appear as large
as the line CD to the spectator G.
The moon is 240,000 miles from the earth, not quite a
quarter of a million of miles. The nearest fixed stars are
20,000,000,000,000. (i. e.. 20 billions.)
if a ball wvent 500 miles an hour, it would reach the
moon in twenty days: but it would not reach the nearest
fixed star in 4,500,000 years. IHad it begun, therefore,
when Adam was created, it would be no further on its
journey than a coach (which has to go from the Land's
End, Cornwall, to the most northern parts of Scotland)
after it has passed about three-quarters of a mile.
Q.   Why does the MOON  (which is a sphere)
APPEAR to be a FLAT surface?
A. Because it is so far off that we
cannot  distinguish  any  difference  between the length of the rays issuing from
the edge and those which issue from  the
centre.
The rays AD and CD appear to be no longer than the
ray BD; but if all the rays seem of the same length, thle
part B will not seem to be nearer to us than A and C; and
therefore ABC will look like a flat or straight line.
The rays AD and CD are 240:000 miles long.
The ray BD is 238,910 miles long.
Q.   W7y do the sun  and STARS (which are
spheres) appear to be FLAT surfaces?
A.   Because  they  are  such  an  im.
mense way off, that we can discern no
difference  of length  between  the  rays
which  issue  fromn  the  edge   and  those




TELESCOPES,                  357
which issue fromn the centre of these bodies.
The rays AD and CD appear no long'.r than BD; and
as B appears to be no nearer than A or C, therefore A, B,
C, must all seem equally distant; and ABC will seem a
flat or straight line. (See last figure, p. 856.)
Q.   Why does DISTANCE make an  object xNVISIBLE?
A. Because no visible perpendicular
can be inserted between tile lines which
form   the  angle;  or because  the  lines
actually cross before they meet our eye..:*
Here the tree AD would not be visible to the spectator C,
even if he were to approach as far as B; because no visible perpendicular can be inserted between the two lines
AC, DC, at the point B, and after B the lines would cross:
Therefore, the tree would be invisible from C, till after the
spectator had passed B.
Q.   Why do  TELESCOPES  enable us to aEE
objects INVISIBLE to the naked eye?
A. Because they gather together
more luminous rays from  obscure objects
than  the  eye  can;  and  form   a  bright
image  of them  in  the  tube of the telescope where they are magnified.
As many times as the dimensions of the object-glass exceed the dimensions of the pupil of the eye, so many times
the penetrating plowers of the telescope will exceed that
of the naked eye.




958                LIGHT.
Q.   When a siJP (out at sea) is approaching
the shore, why do we SEE the small MASTS before we
see the bulky HULL?
A.  Because the earth is rotund; and
the curve of the sea hides the hull flotn
out' eyes after the tall masts have becuuome
visible.
Here, only that part of the ship above the line AG can
be seen by the spectator A; the rest of the ship is hidden
by the swell of the curve DE.
Q.   What is meant by REFRACTION 
A.  Bending a ray of light, as it passes
friom  one medium  to another.
Q.  How is a ray of light BENT, as it passes
front one medium to another?
A.  When a ray of light passes into a
denser medium  it is bent towards the perpendicular. When it passes into a rarer
medium it is bent froin the perpendicular.
3i \                          A
A__________sC _              __




RIVERS.                   359
Suppose DE to be a perpendicular line.
If AB (a ray of light) enters the water, it will be bent
touards the perpendicular to C.
If (on the other hand) CB (a ray of light) emerges
from the water, it would be bent away front the perpen.
dicular towards A.
Q.'VThy does a SPOON (in a glass of water)
always appear BENT?
A.  Because the light (reflected from
the spoon) is refracted as it emergesfrom
the vlater.
See Fig. 2, p. 358. The spoon ABC will appear bent, like
ABD.
Q.'Why does a river always appear more
shallow than it really is?
A. Becatuse the light of the bottom
of the river is REFRACTED, as it emerges
out of the water.
See FiP. 2, p. 358. The bottom of the river will appear
elevated like the bowl of the spoon D.
Q.   How much deeper is a river than it seems
to be?
A. About one-third. If, therefore, a
river seelns only 4 feet deep, it is really
6 feet deep.
The exact apparent depth would be 4j. To find the
real depth, multiply by 4 and divide by 8-thus 4kX4-3
=6, real depth.
N. B. Many boys get out of their depth in bathing, in
consequence of this deception. Remember, a river is always one-third deeper than it appears to be:-thus, if a
river seems to be 4 feet deep, it is in reality nearly 6 feet
deep, and so on.
Q.   Why do fishes seem to be nearer the surface
of a river than they really are?




360                 LIGHT.
A.  Because  the  rays of light from
the fish are refracted, as they emerge from
tilhe eye: and (as a bent stick is not so
far from  end  to end, as a straight one)
so the fishes appear nearer to our eye
than they really are.
See Fig. 2, p. 358.
Q.   Why are some persons NEAR-SIGHTED?
A.  Because the COR'NEA of their eye
is so promninent, that the image of distant
objects is formed before it reaches the
RET'INA; and, therefore, is not distinctly
seen.
Q.   What is meant by the "COR'NEA of the
EYE?"
A.  All the outside of the visible part
of the eye-ball.. The curve ABC is called the CORaNEA.
z~&. /If this curve be too prominent
(or convex), the eye is near-sighted.
If too flat (or concave), the eye is
far-sighted.
Q.   }that is meant by the "d RET'INA of the
EYE?"
A.  The  net-work, which  lines  the
back of the eye, is called the ret'ina.
The net-work ABC is called the ret'v cw          maina, and the projecting part DEF is called
IB       V   the cor'nea.
D   N. B. This net-work is composed of
a spreading out of the fibres of the
nerve of vision.




SPECTACLES.             361
Q.   Whtat sort of GLASSES do NEAr-SIGHTED
persons wear?
A. If the cor nea be too convex (or
projecting), the person must wear double
concave glasses, to counteract it.
Q.  TWhat is meant by " DOUBLE CONCAVE
GLASSES?"
A.  Glasses hollowed-in on bath sides.
\A   The figure A is double concave, or concave on
both sides.
Q.  Where is the IMAGE of objects formsd, if
the cornea be too convex?
A.  If the cor'nea be too conec.x, the
image of a distant object is formed in
the vitreous hunmors of the eye, and not
on the retina.
B1              Thus the image is formed at DE
and not on ABC (the retina).
Q.   Trhat is the use of DOUBLE CONVEX SPEO
TACLE glasses?
A.  To cast the imnage further brck
in order that it may be thrown upon the
ret'ina and become visible.
Q.   TVhy are OLD people FAR-SIGHTED?
A. Because the humors of their eyes
are dried tp by age; in consequence of
16




362               LIGHT.
which, tile COR'NEA sinks in, or becomes
flattened.
Q.  MI7hy does the FLATTENING of the COR'NEA
prevent persons seeing objects which are NEAR? 
A.  Because the  cor'nea is too fat,
and the imace of near objects is not
completely formed, when their rays reach
the RET'INA; in consequence of which,
the image is imperfect and confused.
The perfect image is made at DE;
and not on ABC (the retina).
Q.  WIhat sort of GLASSES do OLD peonle WEAR?
A. As their cor'nea is not sufficiently
convex, they  mnust use  double  convex
glasses, to enable them to see objects
near at hand.
Q.  What sort of glasses are " DOUBLE CONVEX
SPECTACLE-GLASSES?"
A.  Glasses which curve outwards on
both sides.
A]    The firgure A is double convex, or convex on both
Q.  What is the use of DOUBLE CONVEX spe.
JacW-glasses?
A.  To shorten the focus of the eye,




SIGHT.                363
and bring the image of distant objects
upon the ret'ina.
Q.   Wrhy do NEAR-SIGHTED persons bring objects
CLOSE to the eye, in order to SEE THEMI 
A. Because the distance between
the fj'ont and back of the eye is so great,
that the imagre of distant objects is fortned in fr'ont of the ret'ina; but when objects are brou(ht near to the eye, their
image is thrown farther back-, and made
to fall on the ret'ina.
Q.  TItrhy do OLD people HOLD objects FAR OFF,
in order to see them better?
A. Because the distance between
the front atd back of their eyes is not
great enonzh: when, however, objects
are held further off, it compensates for
this defect; and a perfect image is formed on the ret'ina.
Q.   W'hy are HlAWKS able to see such an IMMENSE way/ off?
A.  Because they have a muscle in
the eye which enables them to flatten
their cor'nea, by drawing back the crystalline lens.  See p. 362.
This muscle is called the Marsupium.
Q.  Wty can HAWKS see objects uwithin half-aninch of their eye, as well as those a long way of?
A. Because their eyes arie furnished
with a flexible bony rim, which throws




364                LIGHT.
the cornea forward, and makes the hawk
near-sighted.  See p. 360.
Q.  Into ]how many PARTS may a RAY of LIGHTI
be DIVIDED?
A. Into three parts: BLUE, YELLOW,
and RED.
N. B. These three colors, by combination, make seven.
1.-RED. 2.-ORANGE (or red and yellow). 3.-YELLOW.
4.-GREEN (or yellow and blue). 5.-BLUE. 6.-INDIGO
(a shade of blue); and 7.-VIOLET (or blue and red).
Q.  How is it known, that a ray of lighlt consists of several different colors?
A.  Because, if a ray of light l:e cast
upon a triangular piece of glass (called a
prism), it will be distinctly divided into
seven  colors:  1.-Red; 2.-Oranye;
3.-Yellow;  4.-Green;  5.- Blue;
6.-Irndi(o; and 7.-Violet.
Q.  Wthy does a PRISM DIVIDE a ray of light
into VARIOUS COLORS?
A.  Because  all  these  colors  have,;,fcrent refractive susceptibilities.   Red
is refracted least, and  blue  the  most;
therefbre, the blue color of the ray will
be bent to the top of the prism, and the
red will remain at the bottom.
B
Here the ray AB (received on a prism at B), would




RAINBOW.                   365
have the blue part bent up to C; the yellow part to D:
and the red part no further than E.
Q.   What is meant by the REFRACTION of a
-ray?
A.  Bending it from  its straight line.
Thus the ray AB of the last figure is refracted at B into
three courses, C, D, and E.
Q.   What is the cause of a RAINBOW?
A.  When the clouds opposite the sun
are  very  dark, and  rain  is still falling
from them, the rays of the bright sun
are  divided  by the  rain-drops, as  they
would be by a prism...: 
Let A,, and C, be three drops of rain  SA, and
SC, three rays of the san. SA is divioed nto three colors; the blue and yellow are bent above the eye D, and the
red enters it.
The ray SB is divided into the three colors; the blue is
bent above the eye, and the red tals below the eye D; but
the yellow enters it.
~.;!j I::  ~?., ~  ~'~-..".-i~,~.~  "-~
The ray SC is also divided into the three colors. The
blu;e (which is bent most) enters the eye; Dcr ald'ther
red~~~~~~~( e   n     er i.
Teray SBi   iiedit h  hreclr; h   lei
ben abv   h   yadterdtlsblwteeeD   u
t                    Cheyllo ener it.
Th    e     r ay SC    "is ls   irie   notetre,!r.
blu  (wic  isbn   ot  nesth y;~a;e(&e




366                 LIGHT.
two fall below it. Thus the eye sees the blue of C, and
of all drops in the position of C; the yellow of B, and of
all drops in the position of B; and the red of A, and of
all drops in the position of A; and thus it sees a rainbow.
Q.  Does EVERY person see the SAME colors from
the SAME DRwOPS?
A.  No; no two persons see the same
rainbow.
To another spectator, the rays from SB might be red
instead of yellow; the ray from SC vellow; and the blue
might be reflected from some drop below C. To a third
person, the red may issue from a drop above A, and then
A would reflect the yellow, and B the blue, and so on.
Q.   Thy are there often TWO RAINBOWS at one
and t/he same time?
A.  In one rainbow  we see  the rays
of the sun entering the rain-drops at the
top, and  reflected  to  the eye fromn  the
bottonm.
In the other rainbow, we see the rays
of the sun entering the r ain-dlrops at the
bottom, and  reflected to the top, whence
they reach the eye.
B
/BBLU2
liere the TIy SA (of the primary rainbow) strikes the
drop E.:.-is refracted or bent to B3-is then reflected




COLORS OF THE RAINBOW.    367
to C, where it is refracted again, and reaches the eve of
the spectator. (Sce belouw.)
Here the ray of SB (of the secondary rainbow) strikes
the drop at B —is refracted to A-is then reflected to C
-is again reflected to D, when it is again refracted or
bent, till it reaches the eye of the spectator.
Q.   Wthy are the coLonrs of the SECOND bow all
REVEiRSED?
A. Because in one bow we see the
rays, which enter at the top of the  raindrops, refracted fromL the bottom,:
But in the otlzher bow  we see  the rays
which  enter at tLhe  bottom  of tle  raindrops  (after  two  reflections),'cfr'actcd
from  the to)).
Sce Jfigure on next paze.
Here ABC reprlselnt thrce  drops of rain in the SECONDARY (or upperI)) RAINBOW.
The least refracted line is RED, and BsrUE the vmost.
So the REn (o(r Icast refracted rays) of all thle (drops in
the position of A-the YELLOW of those in thle lsition
of B-and the BLUE (or the most refracted rays) of' the
lowest drops, all meet the eye D, and form a rainblow to
the spectator.
The reason why the primary bow cxlhibits the stronger
colors is this —because the colors are seen after one reflec



368                  LIGHT.
i ion and tho refractions; but the colors of the secondary
ior upper) rainbow, undergo two reflections and two re.
I:
lractions.
(S e figure on p. 365.) Here also the least refracted ray
is RED, and the most reft'acted BLUE (as in the former case);
but the position of each is reversed.
Q.   Why does a SOAP BUBBLE exhibit such a
A. Because the thickness of the film
throu(gl  which  the  rays  pass, is constantly varying.
Q.   II'ow does t0le THICKNESS of the rILM affect
the COLr, of the soap bubble?
A.   Because different dleorees of thickLess  in the filo n produce  different por ters
of reD  action; and, therefore, as the tchickness of the film varies, different colors
reach the eye.
Q.   Why is a SOAP  BUBBLE  so constantly
QHANGING its TH     IC     KNESS?
ofreratin;a     d,~ thrfra  tetic




RAYS.                    369
A. Because the water runs down
front the top to the bottom of tile bubble,
till the  crown  becomes  so  thin  as  to
burst.
Q.   TIfhy are the late EVENING CLOUDS RED?
A.   BecauLse RED rays, being the least
refranrgible, are the last to disappear.
DA
Suppose PA to be a red ray, PB yellow, and PC blue —
if the earth turns in the direction of CBD, it is quite manifest that a spectator standing at C or B (carri ed round
in the same direction), would lose sight of the red rays
(A) last of all.
Q.    frhly are the early MORNING clouds RED?
A.   Because RED rays being  the least
refrangible are the first to appear.
See last figlure.-We must suppose the sun to be on the
left side of' the diagram —or (what will answer the same
purpose) suppose the earth to be turning in the direction
of DAP, then it is quite clear, that every person on the
earth's surface will pass under A (the red rays) before he
passes under B or C, (and theref)re his early morning
rays will be red.)
Q.   TWhy are the EDGES of CL DUDS more LUMINous than thAir C ENITRES?
16'




370               LIGHT.
A. Because the body of vapor is thtin.
nest at the edges of the clouds.
Q.  Thnat is the cause of morning and evening
TWILIGHT?
A.  When the sun is below the horizon, the rays which strike upon the
atmosphere  or clouds  are  bent down
towtards the earth, and produce a little
light called twilight.
Sce figure on p. 369.-Here the rays of PA will give some
light.
Q.  TWHY is a ray of LIGHT composed of vArIovs COLORS?
A. To vary the color of different
objects.  If solar light were of one color
onl1y, all objects wTould appear of that one
color, or else black.
Q.  Some things are of onsE COLOIR, and some
of ANOTHER. Explain the cause of this.
A.  As every ray of ligrht is composed
of all the colors of the rainbow; some
things reflect one of these colors and some
another.
Q.  WHIIY do some things reflect ONE COLOR, and
some ANOTHER 2
A.  Because the surface  of things is
so differently constructed, both physically
and chemically.
Q.   Why is a ROSE RED?
A. Because the surface of a rose ab



COLOR.                  371
sorbs the blue and  yellow  rays of light,
and reflects only the red.
Q.   Why is a VIOLET BLUE?
A. Because the surface of the violet
absorbs the red and yellow rays of the sun,
and reflects the blue only.
Q.  WThy ts a PRIMROSE YELLOW?
A. Because the surface of the primrose absorbs the blue and redc rays of solar
light, and reflects the yellow.
The chief reason why some rays are absorbed and others
reflected is, because the corpuscles which compose the col.
ored substance vary in magnitude:-thus, for example, if
the diameter of a corpuscle of equal density with air be
21 millionth of an inch. it will reflect purple; if, on the
other hand, it be 29 millionth of an inch, it will reflect
red, and so on.
Q.   TIfhy are some things BLACIK?
A.  Because they absorb all the rays
of light and reflect none.
Q.   Why are some things WHITE?
A.  Because they absorb  none of the
rays of light, but reflect them  all.
Q.   Why are COALS BLACK?
A.  Because they absorb all the rays
of the sun which impinge upon them.
Q.   Why are FROTHI, and SPRAY) and many
CLOUDS, WHITE?
A. Because they consist of an infinite
number of small bubbles or vesicles,
which  act like prisms in  dividing  the




372               LIGHT.
rays of' light; which, by uniting agaiin
before they meet the eye, give the appearance of white.
Q.  TIhy are SNOW, SUGAR, and SALT WHITE 
A. (See pagye 312.)
N. B. The combination of all colors makes WHITE.
Q.  TWVhy are the LEAVES of plants GrEE N?
A. Because a peculiar chemrical principle, called chlo'rophyll, is form-ned within
their cells; which has the property of
absorbing the red rays and of reflecting
the  blue and  yellow;  which  mixture
produces green.
Chlorophyll (XXwpov OvXXov, a green leaf) is the green
matter of vegetable substances. PoiwaVt'ce klo-ro-fill.
Q.  WThy are leaves a LIGUT green in SPRING?
A.  Because the  chlo'rophyll is not
fully formied.
Q.  Wlhy do leaves turn BnrowN in AUTUMN?
A.  Because the clllo'rophyll undergoes decay, and is not replaced  as it is
in spring.
Q.   IVhy are plants a PALE YELLOV, when
kept in the DARK?
A.  Because chlo'rophyll can be formed only by the agency of the stuz's r ays.
Q.  Why are POTATOES YELLOW?
A.  Because they are grown under.
ground; and, therefore, can  form   no
chlo rophyll in their tubers.




TRANSPARENCY.             373
Q.  Why are potatoes which grow EXPOSED to
the air and light GRE EN?
A. Because chlo'rophyll is formed in
them  under the influence of the sun's
light.
Q.  Why are SOME things TRANSPARENT?
A.  Because every part between the
two  surfaces has a uniform  refracting
power, or (in other words) has in every
place the same density.
And, therefore, the rays of light emerge on the opposite
side.
Q.  Why are some things NOT TRANSPARENT?
A. Because the particles which compose them are sfparated by minute pores
or spaces, which have a different densit7
fiom  the particles themselves.
Therefore, the rays of light are reflected and refracted
too often to emerge.
Q.  Why are DRY PAPER and calico (which are
OPAQUE) made transparent by being OILED? 
A. Because the pores are filled by
the oil, which has nearly the same density as the substance of the paper itself
-by which means a uniform density is
effected, and the substance becomes
transparent.
Q.  WThy is GLASS (which is transparent) rendered OPAQUE by being ground or pzulverized?
A.  Because  the  whole  substance




374               LIGHT.
from  surface to surface is no longer of
one uniform  density.
Q.  W/hy are SOMiE thizng-s SuTINING and others
DULL?
A.  Because some things reflect rays,
and are bright; but others absorb them.
Q.  Why do DESERTS DAZZLE from sunshie e?
A.  Because each grain of sand rejfects
the rays of the sun like a mirror.
Q.  If yoU move a stick (burnt at one end)
pretty briskly AROUND) it seems to make a CIRcLE
OF FlrE -WIIY is this?
A.  Becau:se the eye retains the image
of any bright object, after the object itself
is withdrawn,; and as the spark of the
stick returns before the im-tage has faded
from  the eye, it seems to form a complete
circle.
Q.  If separate figures (as a man and a horse)
be drawn on separate sides of a card, and the card
TWISTED quickly, the man will seem to be seated on
the horse-WhY is this?
A. Because the imagoe of the horse
remains upon the eye till the mant  appears.
The Thaumatrope is constructed on this principle.
Q.  TWhy do the STARS rWINKLE?
A. Because the inequalities and undulations in the atmosphere produce unequal refractions  of light;  and  these




ACCIDENTAL COLORS.            375,inequal refractions cause the twvinkling
or irregular brilliancy of the stars.
Q.  If we look at a RED-HOT FirE for a few
minutes. wnY does every thing seem TINGED wilth a
BLUISH GREEN color?
A. Because bluish green is the
ACCIDENTAL COLOR" of red; and if we
fix our eye upon any color whatsoever,
we see every object tinged with its accidental color when we turn aside.
The acciddental color is the color which would be required
to be added, in older to make up while light. S:c p. 360.
Q.  IWhy does the eye perceive the ACCIDENTAL
COLOR when the fandamenltal one is removed?
A. Because the nerve of the eye has
become tired of the one, but still reimnains
fresh for the perception of the other.
Q.  ]f we weanr BLUE GLASSES, why does every
thing appear tingled with ORANGE whea we take them
of?
A. Because orange is the " accidental
color " of blue; and if we look througrh
blue glasses, we shall see its " accidental
color" when we lay our glasses aside.
Q.  If we look at the SUN for a few moments,
every thing seems tinged with a VIOLET color —WHI
is t'is?
A.  Because violet is the " accidental
color" of yellowv; and as the sun is yel/,lo, we shall see its " accidental color"
violet when we turn fionom gazing at it.




376                 LIGHIIT.
Q.  Does not the DARIC STADow (which seems is
hang over every thing after we turn from looking at
the stal) arise from our eyes being, DAZZLED?
A.  Partly so: the pupil of the eye is
lery wliuch contracted by the brilliant light
of the sun, and does not adjust itself immediately to the feebler lightt of terres.
trial objects;  but, independent of this,
the " ACCIDErNTAL  COLOR " of the sun beinz  clark violet, would  tend  to throw  a
shadow  upon all thinigs.  (Se p. 340.)
Q.   tEhy is BLACK glass for spectacles the BEST
for wear ill this respect?
A.  Because  white  is the  accidental
col,:r of black;  and  if we  wear black
glasses, every thinr will appear in white
light -when we take them  off.
Q.   IVhTy does every tlhizg seem shadowed with
a BLACK MIST when we takie off our commeon SPECTACLES?
A.  Because  the  glasses  are  white;
and black being) its " accidental color,"
every thing appears in a black shade when
we lay our glasses down.
The accidental color of red   is bluish green.
it ".... of orange " blue.
cc"   "      "  of violet " yellow.
it    " "    "  of black  " white.
And the converse of this is true:The accidental color of bluish green is red.;   "  " Cof blue      "orange.
t"    " " of yellow'violet.
"   "  "  of white     "black,




SOUND.                    377
(The law of an accidental colcr is this —The accidental
color is always half the spectrum. Thus, if -we take half
the length of the spectrum by a pair of compasses, and
fix one leg in any color, the other leg will hit upon its accidental color.)
N. B. The spectrum means the seven colors (red, orange, yellow, green, blue, indigo, and violet), dividlutd into.even equal bands, and placed side by side in the order just
mentioned.
SOUND.
CHAPTER XXX.
Q.   How is SOUND produced?
A. The vibration of some sonorous
substance  produces  motion  in  the  air,
called  SOUND-WAVES, which  strike  upon
the drunk  of the car and  give the sensation of sound.
Q.   qWhat are MUSICAL SOUNDS 2
A.   Regular and  uniform  successions
of vibrations.
Q.   How FAST does SOUND TRAVEL?
A.   About 13  miles in  a minute, or
1142 feet in a second of time.
Light would go 480 times round the whole earth, while
sound is going its 13 miles.
Q.   ThYVy are SOME t/hings SONOROUS and otherj
NOT?
A.  The sonorous quality of any subs
stance  depends upon  its hacdnlcss and
elasticity.




378               SC UND.
Q.  Why atre coPPErn ana IRtON SONOrOUs and
not LEAD?
A.  Copper and iron  are hard and
elastic; but as lead is neither hard nor
yet elastic, it is not sonorous.
Q.  Of what is BELL-METAL made?
A.  Of copper and tin in the following
proportions:-In every 5 pounds of bellmetal there should be 1 pound of tin,
and 4 pounds of copper.
Q.  ltil/ is this nixture of tin and copper used
for nELL-'MsILTAL?
A. Because it is much harder and
more elastic than any of the pure metals.
Q.  HTqAy is the SOUND of a bell STOPPED by
TOUCHING the bell with cur.finger?
A.  Because the weight of our finger
stops the vibrations of the bell; and as
soon as the bell ceases to vibrate, it ceases
to make sound-waves in the air.
Q.  Why does a SPLIT BELL make a hoarse, disagreeable sound?
A.  Because  the  split of the  bell
causes a double vibration: And as the
sound-waves clash and jar, they impede
each other's motion, and produce discordant sounds.
Q.  WI7y does a FIDDLE-STRING give a musical
sound?
A. Because the bow drawn across
the stringl causes' t.e  21blhrate; and this




MUSICAL SOUNDS.          379
vibration of the string sets in nzoltion the
sou-nd-craves of the air, and produces
musical notes.
Q.  Tih?/ does a DriUM sound?
A.  Because the parchment head of
the drum vibra'tes fr'om  the blowv of the
drum-stick, and sets in motion the soundwaves of the air.
Q.  Whfty (do MUSICAL GLASSES give sounds?
A.  Because the glasses vibrate as
soon as they are struck, and set in motion
the sound-waves of the air.
Q.  Why do FLUTES, 4.c., produce musical
sounds?
A.  Because the breath of the performer causes the aiir in the flute to vibrate; and this vibration sets in motion
the sound-waves of the air.
Q.  Why do PIANO-FORTES produce musical
sounds?
A.  Because each key of the piano
(being struck with the finger) lifts up a
little hammer which knocks against a
string; and the vibration thus produced
sets in nlotion the sound-waves of the air
Q.  Hfh.y are SOME notes BASS, and some TREBLE?
A. Because slow vibrations produce
bass or deep sounds; but quick vibrations
produce shrill or treble ones.




380                 SOUND.
Q.   W'hy is an  instrument FIAT when thd
BTRPINGS are UNSTRUNG? 
A. Because the vibrations are too
slow;  in  consequence  of  which, the
sounds produced are not sh/ill/ or sharp
enougrh.
Q.   Irhy can persons, living a mile or two frcrm
a town, HEAR the BELILS of the town churches so:ETlIMl:S a~nd not at OTHERS 2
A. Because fogs, rain, and snow,
obstruct the passagre of sound; but when
the air is colld and clear, sound is propagated more easily.
Q. Wavr can we NOT hear sounds (as those of
distant church, bells) in RAINY weather so well as in
FINE  ealther?
A.  Because the falling rain inlteiferes
with the'un dulations of the sound-zwaves,
and breaks them up.
Q.   Why can wue not. hear sounds (as those of
distant church bells) in sNowY weather so well as in
FINE wealher?
A.  Because  the fallinog  snow  interferes withl tlle undalatiotZs of the sountdcaves, and stops their progress.
Q.  WLhy can we HEAr distant clocks MOST distinctly in CLEAR COLD weather?
A.  Because the air is of more ut/bfor7m
lZensity, and there are fewer currents of
air of unequal temperature to interru.pt
the sound-waves.




DISTANT SOUNDS.               381
Besides, dense air can propagate sound-waves more
readily than rarer air.
Q.  Why can persons (near the POLES) hear the
VOICES of men in conversation for a MILE distant in
winter-time?
A.  Because the air is very cold, clear,
and still; in consequence of which, there
are but few  currents of air of unequal
temperature  to  interrupt  the  soundwaves.
Captain Ross heard the voices of his men in conversation a mile and a half fiom the spot where they stood.
Q.   Why?/ are not SOUNDS (such as those of distant church bells) heard so distinctly on a HOT DAY
as in FROSTY weather?
A. lst-Because the density of the
air is less uniforn- in very hot weather:
2dly —It is more rarefied; and, consequently, a worse conductor of sound: and
3dly-It is more liable to accidental
currents, which impede the progress of
sound.
Q.   iVh/  can we not hear SOUNDS (such as
those of distaLnt clocks) so distinctly in a thick MIST
or HAZE as in a CLEAr, night?
A.  Because the air is not of uniform
density when it is laden  with mlist; in
consequence of which, the sound-waves
are obstructed in their progress.
Q.   Thy do we hear SOUNDS better by NIGHT
than by DAY?
A. 1st-Because night air is of more




382              SOUND.
unifornm  density and less liable to acci.
dental currents: and
2dly —Night is more still from  the
suspension of business and hum of men.
Q.  TIVhy is the air of more UNIFORM DENSITY
by NIGHT tha/a it is by day?
A. Because it is less liable to accidental currents; inasmuch as the breezes (created by the action of the sun's
rays) Leenerally cease during the night.
Q.  I-ow should PARTIT[ON WALLS be made, to
PREVE NT the voices in adjoining rooms from being
HEARD?
A.  The  space  between  the  laths
should be filled with shavings or savwdust; and then  no sound would ever
pass fromn one roo-n to another.
Q.  TVhy would SUHAVINGS, or saw-dust, PREo
VENT the transmission of soutndl fom room to room?
A. Because there would be several
different imedia for the sound  to pass
throlugh: 1st —the air; 2dly-thlle laths
and pip)er; 3dly-the saw-dust or shaving's;  4ttily —lath  and  paper argain;
5thly-the air afgain: And every change
of mediumn diminishes the streng?,rth of the
sound-wcaves.
Q.  Whhy can DEAF people hear through an
EAR,"TR~UM PET?
A.  Because the ear-trumpet restrains




ECHO.               383
the spread of the voice an(l limits the diameter of the soatnd-woaves: in consequence
of which, their strength is increased.
Q.  Why are M3UNTAINS NOISELESS and quiet?
A. Because the air of mountains is
very rarefied; and, as the air becomes
rarefied, sound becomes less intense.
Q.  HIow do you know that the RARITY of air
DIMINISHES the intenlsity of SOUND?
A. If a bell be rung in the receiver
of an  air-pump, the  sound  becomes
fainter and fainter as the air is exhausted; till at last it is almost inaudible.
Q.  What is the cause of ECIO?
A.  Whenever a sound-wave strikes
against any obstacle (such as a wall or
hill), it is reflected (or thrown back); and
this reflected sound is called an ECHO.
The same laws govern echo as light. (See pi. 338.)
Q.  What places are most famous for ECHO?
A. Caverns, grottoes, and ruined abbeys; the areas of halls; the windings
of long passages; the aisles of cathedral
churches; mountains and icebergs.
Q.  Why are caverns, grottoes, and ruins, FA
mous for ECHOES?
A. 1st-Because the souind-waves
cannot pass beyond the cavern or grotto,
and, therefore, mustflow back: and
2dly —The return-waves (being entan



384                BOUND.
gled by the cavern) are detained for a
short time, and come deliberalely to the
ear.
Q.   Why are halls, winding passages, and ca.
thedral aisles, FAMoUSfor ECIOES?
A.  Because the sound-waves cannot
Jflow  f'eely  forwlard;  but perpetually
strike  against the winding  walls, and
are beaten back.
Q.   Why are MOUNTAINS and icebergs FAMOUS
for ECHOES?
A.  Because they present a barrier to
the sound-waves, 7which they cannot pass,
and are sufficiently elastic to throtw themn
back.
Q.   Why do not the WALLS of a ROOM or church
produce ECHO?
A.  Because sound travels with such
velocity that the echo is blbndlcld zwith the
original sound;  and  the two  produce
but one inmpression on the ear.
Sound travels 13 miles in a minute; and no echo is
heard, unless the surface (against which the sotund strikes)
is 65 fCct from the place whence the sound originally proceeded.
Q.  WHthy do very LARGE buildings (as cathedrals) cOten REVERBERATE the voice of 1te sneaker?
A. Because the walls are so ftr off
fronm  the speaker that the echo does not
get back in time to blend with the origi



ECHO.                    38S
nal sound; and, therefore, each is heard
separately.
Q.    YVALy do SOME echoes repeat only ONE syllable?
A.   Because the echoing body is very
near'.  rThe further the echoing  body is
off, the  more  sound  it will reflect:  If,
therefore, it be very near, it will repeat
but one syllable.
Q.   lIt.hy does an ECHO sometimes repeat TWO
or more syllables?
A.   Because the echloing  body is far
off; and, therefore, there is time for one
reflection  to pass  away  before  another
reaches the ear.
N. B. All the syllables must be uttered, before the echo
of the first syllable reaches the ear-If, therefore, a person repeats 7 syllables in 2 seconds of time, and hears
them all echoed, the reflecting object is 1142 feet distant;
(because sound travels 1142 feet in a second, and the
words take one second to go to the reflecting object, and
one second to return.)
Q.   Ifhy are TWO or more ECHOES sometimes
heard?
A.   Because  separate  reverberating
surfaces receive the sound and reflect
it in succession.
17 miles above Glasgow (Scotland) near a mansion called
Rosneath, is a very remarkable echo. If a trumpeter
plays a tune and stops, the echo will begin the same tune
and repeat it all accurately:-as soon as this echo has
ceased, aiwther will echo the same tune in a lower tone;
and after the second echo has ceased. a third will succeed
with equal fidelity, though in a much feebler tone.
17




s386               WINDOWS.
At the Lake of Kilkarrev in IRELAND, there is an echo
which plays an excellent "sccond" to any simple tune
played on a btgle.
Q.   WhYy do WVINno WS RATTLE awhen CARTS
pass by a house?
A.   1st-Because  glass is sonorotz;
and the air communicates its vibrations
to  the  glass, which  echoes  the  samne
sound: and
2dly —The  wvindowo-fiame  being  shaiken, contributes to the noise.
Window frames are shaken, 1.-By sound-waves impinging against them; 2. —By a vibratory motion communicated to them by the walls of the house.




PART III.
MISCELLANEOUS.
*  This part is little else than a collection of various
questions propounded by different correspondents, pupils,
and private fiiends, set down, without regard to arrangemcnt, in the order in which they were proposed; together
with a few leading questions to break up some which
would have been otherwise too intricate, and others which
naturally arose out of the subject under consideration.
Q.   Wt7Thy do the BUnnBLs in a cuP of TEA rantge
round the SIDES of the cur?
A.  Because the cup attracts thcim.
Q.   IhIty do all the LITTLE BUBBiLES tend towards the LARGE ones?
A. Because the large bubbles (being
the superior masses) attract them.
Q.  IWhy do the BUBBLES of a cuP OF TEA
FOLLOW a TEA-SPOON?
A. Because the tea-spoon attracts
them.
Q.   TVhy are the SIDES of a pond covered with
LEAVES, while the MIDDLE of the pond is quite
CLEAR?




388      CAPILLARY ATTRACTION.
A.  Becaulse  the  sho re. attracts the
leaves to itself.
Q.   T/hy do allftauits. tc., (when severcdj f-on
the tree.) FALL to the EARTH?
A.  Because thle earth attracts thezm.
Q.   TZhVy (1o pcrsons who u;ater PLANTS very
often pour the walter into the SAUCERP, and not over
the PLAN'rs?
A.  Because the water in the saucer
is d(rawnv tup by the mould (thlrough tile
hole at the bottom  of the  flower-pot)
and is tr'ansferred to the stem and leaves
of the plant by CAPILLARY  ATTRACTION.
(See p. 75.)
Q.  IThy is vegetation o0n the MARG(IN of a rPIv
ER zoire LUXURIANT than, in a-n open FIELD?
A.  Because the porous earth on the
batik drawts utp) wcater to the roots of the
plants by CAPILLAR.Y  ATTRACTION.
Q.  [I"Th1y is a LUMP of SUGAR (left at the botton
of a cup) so LONG in MELTING?
A.  Becaiuse (as it melts) it makes the
tea above it heavier; and (so long as it
remains at the bottom) is surrounded by
tea fully saturatled with suglar; in corsequlence of which, tlle samne portions of
liquid will hold no nlore sugair in solution.
Q.  WJhy does the LUMP of SUGAR MELT mort
QUICKLY uhen STIRRaED ABOUT?
A.  Because fresh portions of unsate i




EFFLUVIA.             389
rated tea come in contact with the lump,
and soon dissolve it.
Q. Why does a PIECE OF SUGAR. (held in a
spoon at the TOP of our tea) melt very RALPDI,Y?
A. Because, as the tea becomes
swieetened, it dlescendls to the bottom of the
cup by its own gravity; and fiesh portions of unsweetened tea are brought
constantly into contact with the su(ar
till the lump is entirely dissolved.
Q.  fIow can a sIci ROOM be lkept FREE from
unhealthy EFFLUVIA?
A.  By  sprinkling  it with  vinegar
boiled with myrrh or camphor.
Q.   TVh/y does LTME destroy the o.fensive smells
of BINS) SEWEERS, 4c.?
A. Because it decomposes the offensive gases upon which the smell depends,
and destroys them.
Q.  WlFhy does cnLORnIDE of LIMIE fumigate a
sick room?
A.  Because the chlorine absorbs the
hydrogen of the stale air; and by this
means removes both the offeisive snmell
and the infction of a sick room.
Q.  Ifo07. can the TAINT of MEAT be removed?
A.  Either by washin( with PYROLIG -
NEOUS ACID-or by covering it for a few
hours with common CHARCOAL-Or by




390          TAINT REMOVED.
putting a fev lumnps of charcoal into the
water in,wltich it is boiled.
Q.  Why do these things DESTROY the TAINT oJ
meat?
A.  Because they conmbine with the
putrescent particles, and neutralize their
offensive taste and smell.
Q.  TWVhy should BED-ROONIS, COTTAGES, IIOSPITALS, andl STABLES, be washed occasionally with
LIME WHITE?
A. Because the lime is very caulstic,
and removes all organic matters adhering to the walls,
Q.  WVhy will strong SovcIiONG TEA POISON
FLIES?
A.  Because it contains prussic acid,
which destroys their nervous system.
Q.  lWrhy is strong GREEN TEA UNWXHOLESOME?
A.  Because it contains prttssic acid,
which destroys the nervous systemn.
Q.  Why is a DEAD man TALLER than a living
one?
A.  Because at death the CARTILAGES
are relaxed.   So, also, after a nighlt's
rest, a man is taller than when lie went
to bed.
Q.   ihat is SLEEr?
A.  Sleep is the rest of the brain and
nervous system.
Q.  Hfhy can we not SEE, when uwe are asIeep
with our EYES OPEN?




THE SENSES.             391
A. Because the " RET INA Of the eye"
is inactive and at rest.
Q.  Whly can we not HEAR in sleep?
A.  Because  the nerve  of hearing
(seated within the TYIPrANUM of the ear)
Is at rest.
Q.  Why can we not TASTE when we are asleep?
A.  Because the nerves at the end of
the tongue (called papille) are inactive
and at rest.
Q.  IThy can we not FEEL when we are asleep?
A.  Because the ends of the nerves
(called papillae) situated in the skin, are
inactive and at rest.
Q.  Why have persons in sleep no WILL of their
own, but may be moved at the will of ANY one?
A.  Because the  "cErEBELLUM"V (or
posterior part of the brain) is inactive
and at rest.
Q.  Wthy have DREAMERS no power of JUDGM1ENT or REASON?
A.  Because  the  "CEREBRUM " (or
front of the brain) is inactive and at rest.
Q.  Why do some persons LOSE all POWER of
SENSATION?
A.  Because  the  "CEREBRUM"  (or
front of their brain) has been injured.
Q.  Why does a person FEEL when he is
TOUCIIED?
A.  Because  the  ends  of  certain




892            REFRACTION.
nerves (called " PAPILL.E") situated in the
skin, are excited; and produce a nervous
sensation called FEELING.
Q.  Why are persons able to TASTE DIFFERENr
FLAVORS?
A. Because the " PAPILL.E" Of the
tongue and palate are excitedl when food
touches them, and  produce a nervous
sensation called TASTE.
Q.  T'Vthy are OLD people UNABLE to WALK?
A.  Because  their  msascles  beconme
r, igid.
Q.   Why does ABUNDANCE of DEW sn. the morning indicate, that the day will be FiNE? p. 189.
A.  Because dew is never deposited
in dull, cloudy weather, but only in very
clear, calnz nights; when the cold currents
of air are not mixed  with tlhose of a
warmer temperature.
Q.  Why does an OAR in water appear bent?
p. 358.
A.  Because the part out of the water
is seen in a diffierent medium to the part
in the water; and the rays of tlhese two
parts, meeting together at the surface of
the river, formn  anz acngrle- -or, in other
words, make the oar look as if it were
bent.
As all the rays of light are refracted (or bent) mnore in
their passage through water than in their passaget through




COLOR.                 393
air, they will tend to cross each other at the surface of
the water, and, of course, form an elbow or angle.
Q.   If a piece of BROWVN PAPER be submitted to
the action of a BURNING GLASS, it will catch fire
much SOONER than a piece of white paper would;
Exp':lain the reason. p. 175.
A.  Because wvhite paper reflects the
rays of the sun, or throws them back;
in consequence of which, it appears more
lurinous, but is not so much heated, as
dark brown paper, which absorbs the rays
and readily becomes heated to ignition.
Besides, brown paper is of a looser and more combustible fabric than white paper.
Q.   Why does a lady's BLUE DRESS appear
GREEN by CANDLE LIGHT? pp. 76, 364.
A.  Because the light of a candle is
tinged with yellowo; and this yellowo tinge,
mixingc with the blue dye of the dress,
produces green.
Q.  MIy does the SUN look red in a FOG? p.
127.
A.  Because red rays have a greater
momentum than any other rays; and
this superior momentum enables them to
penetrate the dense atmosphere more
readily than either blue or yellow rays,
which are either absorbed or reflected by
the fog.
" Momentum " means, the impetus or power of p.m.etra-.
ing the fog.
17*




394                INK-SPOTS.
Q.   Why is an INK-SPOT onb linen BLACK WAen
first rmade?
A.   Because the ink produces a chemni
cal chance in the internal condition of
the fibres of the linen, by which it loses
its power of reflecting  light; and, as it
absorbs the  rays  of the  sun, the  spot
seems black.
The black color of ink is composed of a compound of
Tannic acid, sesqui-oxide of iron, and water.
" Tannic acid " is an acid which exists in oak trees, especially in the bark, but is abundant in nutgalls. It derives its name from its property of combining with the
skins of animals and converting them into leather, which
is called tanning them.
"Sesqui-oxide of iron " means, that one atom iand a half
of oxygen is mixed with one atom of iron.-The amount
of oxygen in an oxide is always expressed by somne similar
affix, thus
Protoxide-1 atom of oxygen~
PrBinotoxide-  atom of oxygen   and one of the
Binoxide-2 atoms of oxygen  substance oxidized
Toroxide-3 atoms of oxygen   called the base.
Per-oxide-the highest possible degree of oxidation,
&c.
Sesqui-oxide-11 atom of oxygen and 1 of base.
Q     WhLy does the black ink-spot on linen turn
YELLOW after a few days?
A.   Because  the  compound,  which
composes the  blackness of ink, is  destroyed by exposure to air; and the linen
partially recovers its power of reflecting
colors, but with  a preference  to  yellow
rays.
The tannic acid and %wa" r are in a measure taken ur
by the air, and the oxide of iron leaves a yellow iron
mould behind.




CANDIE FLICKERING.         395
Q.  Why does BRUSHING the HAIR much make
lhe head itch? p. 142.
A. 1st-Because the friction of the
hair-brush excites electricity in the hlair,
which thus becomes overcharged and irritates the skin: and
2dly-The   hair-brush   excites  increased action in the vessels and nerves
of the scalp, producing a slight degree of
inflammation, which is indicated by a
sensation of itching.
Q..Zihy does a CANDLE FLICKER, especially
just previous to its being BURNT OUT? pp. 76, 80.
A. Because it is tunequcally supplied
with combustible gases. —When a candle
is nearly burnt out, there is not sufficient
tallow or wax to keep up the regular
supply of combustible gas; in consequenlce of which, the flame flickers, i. e
blazes, when it is supplied with gas, and
goes out for a moment, when the supply
is defective.
Q.  If the " corrER" (or boiler) attached to a
kitchen range, be.filled with cold water AFTER the fire
has been some time lighted, it will very often CRACK
(or burst).  Why is this? p. 118.
A. Because the hteat of the fire has
caused  the "copper" to expand; but
the cold water very suddenly condenses
again those parts with which it comes in




896               FLAG-STONES.
contact: and, as one part is la;rer than
the other, the copper cracks or bursts.
Q.   WTThat is color?
A.   An  inherent property  in light.The reason why different things appear
of different colors, is owingr to their power of reflecting some rays and  absorbing
others.
N. B. It must not be forgotten, that color is not an Inherent property of' the flower, carpet, rainbow, &c., but an
inherent property of the lirt/,  which falls upon them.
The reason why one thing reflects one ray. and another
thing reflects another ray, is ofwing to the difflrent thickness of the corpuscules which compose them —the acid or
alkaline properties of their juices or dyes-the unifolrmity
and texture of their parts-and so on; in consequence of
which, some ray or rays are reflected in preference to
others.
Q.   WIhy, do all things appear BL.ACK in t/u
DARK? p. 371.
A.   Because there is no light; and as
color is the  inherent property  of lilght,
therefore, in the dark all things are wvithout. color.
Of course, in certain degrees of darkness, objects aro actually invisible. The question refers to that peculiar degree of darkness, when the forms of objects may be seen,
but not their hues.
Q.    ArtIy are the FLAG-STONES of our streetsfrequeltly LOOSENED after a FROST? p. 326.
A.   Because  the  nmoisture   beneath
them,  expanded  during  the  frost  and
raised  the  flag-stones fiom   their beds;
but afterwards, the moisture thawed and




WARM ROOMS.             897
zondensed agoain, leaving' the flag-stones
loose.
Q.   Whr. y is a nooM WARMER, when the window CU'RTAI^tN are DRAWN? p. 1C5.
A.  Because air is a bad conductor;
and the air, confined between the curtains and(l the window,' opposes both the
escape of wlarm air out of the room, and
of cold.tairi into the roomn.
Q.  1U,7hy are rooms much tvWAbrMr, for being
furnished ut'dh DOUrILE DooRS anld WINDOWS? p.
165.
A.  Because air is a cbad conhuctor;
and the air confined betwveen the double
doors and l  indows, opposes both the escape of'rtvran air out of the room and of
cold air i/tao the room.
Q.  I~hy is LOOSE clothingr WARnMErt than
that which fitls closely? p. 165.
A. Because air is a bad conductor;
and the qilantity of air, confined between
our body and clothing, prevents; 1stthe heat of our body from escaping; and
2dly —ITle external air from coming into contact with our body.
Q.  IVhy does WETTJNG a CORNELTAN make it
more TRANSP.ArENT? p. 373.
A.  Because the pores of the corneHlan are then filled \with vlater; and as
the density of the mass is rendered some



398         RUSTY  IRON-PFIRES.
what  more  uniform  than  when  tnose
pores were filled with air, the stone becomes more transparent.
The water on the surface of the stone acts also as a var.
nish, to make the external coating more lustrous.
N. B. Transparency depends on the uniformitv of parts.
If the parts of' any substance are not pretty uniform, the
rays of light are refracted and absorbed so frequently, that
no part of them can emerge on the opposite side.
Q.  WThy does IRON rust?
A. Because water is decomposed,
when  it comes in contact with the  surface of iron; and the oxygen of the water  combining  with  iron  produces  an
oxide, which is generally called rust.
N. B. Water is a compound of Oxygen and Hydrogen,
in the following proportions: 8 lbs. of oxygen, and 1 lb.
of hydrogen=9 lbs. of water.
Q.  XW hy does PAINTING iron prevent it from
RUSTING. p. 232.
A. Because paint prevents the moist
air from  coming in contact with the iron.
Q.   Why is a dull FIRE REVIVED by sweeping
clean the hobs: bars, ash-grate, 4~c. of the stove? pp.
52, 53.
A. Because the air, which was arrested by the loose dust and coals, finds
its wayfr'eely to the fire, so soon as these
obstacles are swept away.
N. B. The brightness of a fire depends on its supply of
oxygen, derived from the air.
Q.   Why does STIRRING a dull FIRE serve to
ksic'xa  it? pp. 52, 53.
A, Because it bre&a — up the clotted




BREAD, ETC.            399
cinders and coals, making a passage for
the air into the very heart of the fire.
A lire should be stirred from the bottom, and not from
the top.
Q.  Why does sOAPY WATER " lather?" p.
924.
A.  Because soap makes the water
tenacious, and prevents its bubbles from
bursting; "Lather" is only an accumulation of bubbles.
Q.  Why is well-made BREAD fall of holes or
eyes? p. 257.
A. Because the fermentation of the
dough throws up little bubbles filled with
carbonic acid gas; and when the dough
is baked, these bubbles are made permnanent in the bread.
Q.   rhy do the SAILS of a WIND-MILL turn
round? p. 108.
A. Because the wind, blowing against
the oblique surface of the sails, pushes
them out of the way, drlliving them  from
place to place in a restless round.
Q.   After striking a finger-glass, why is the
SOUND SILENCED, Upon touching the glass wzth your
finger? p. 378.
A. Because the pressure of your finger stops the vibrations of the fingerglass; and, so soon as the finger-glass
ceases to vibrate, it ceases to make soundwaves in the air.




400        STARS TWINKLING.
Q.   TVYhy does a WET SPONGE CLEAN a SLATE t
p. 321.
A. Because the water of the wet
sponge dissolvbes the pencil marks made
upon the slate.
Something is due to the mechanical action of the mere
friction.
Q.   Waldhy do STARS TWINKLE more thlan usual,
just previous to RAIN? p. 374.
A. lst-Because the air is unequally
filled with vapor, which offers constant
obstructions to the passage of the rays:
and
2dly-Because   clouds   and   other
opaque vapors passing through the air,
veil for a little time the light of the stars,
which again becomes apparent after the
clouds have passed:-This constant shutting off the lighllt for very brief intervals,
produces what is called twinkling.
The answers are not altogether satisfactory: probably
difraction and the interference of different rays with each
other, will be found, at some future time, to explain the
phenomenon better.
Q.  Ihrhy does MILK BOIL OVER  lore readily
than water? p. 324.
A. Because the bubbles of milk, produced by the process of boiling, are more
tenacious than the bubbles of water; and
these bubbles, accumulating and climb



GLAZED PICTURES;, ITC.      401
ing  one  above another, soon  overtop
the rim of the saucepan and run over.
Q.  If a PICTURE be GLAZED, yoU cannot see the
"print" in certain positions; why not? p. 352.
A.  1st-Because glass is a reflector;
and, whenever the strong( light of the
sun is reflected from the glass to the eye
of the spectator, the (glass becomes intensely luminous, and the picture remains in comparative darkness: and
2dly-When the spectator is so placed,
as to catch  the rays of lighlt reflected firom  the glass, his eye is dazzled
with the strong light, and cannot see
the more faintly illuminated picture behind it.
Q.  DUST very RARxELY flies by NIGHIT: why
ts this? p. 188.
A.  1st-Because the dews of nio-ht
moisten the dust, and prevent its rising
into the air: and
2dly-As the surface of the earth is
colder than the air after sunrset, the current of the wind will incline dwlonzward;
and tend rather to press the dust down:
than to buoy it up.
Q.  W7Men the cork of a SODA —WATER bottle is.
drawn, why is a loud o: trorTr made? p. 102
A.  Because sotla-water cortaintselghtt




402    SODA-WATER BOTTLES, ETC.
times its own bulk of carbonic acid gas;
which, being suddenly liberated, strikes
against the air, and produces a report.
In the same way, as when we strike our hand upon the
table.
Q.  MW7y does the CORK of a SODA-WVATErP bottyl
FLY OFF, the instant it has been released from the
bond which held it in? p. 102.
A. Because the vast quantity of carbonic acid gas forced into the soda-water can no longer be confined; and seeking to escape, drives out the cork with
great violence.
Q.   Wi/hy do our HANDS and LiPS CHAP in
frosty and winl? weather? p. 295.
A.  1st-Because the  wind or frost
absorbs the moisture from  the surface
of the skinrt: and
2dly-The action of wind or frost
produces a kind of inflammation on the
skin.
Cold acts very readily upon the skin, exciting a kind of
crysipelas, of a red color; if the cold is continued, the
skin becomes pale and languid, and the patient suffers
from chaps, chilblains, &c. The question, however, is
one belonging to the physician, rather than the natural
philosopher.
Q.   lVhen a BLACK SUBSOIL is dug or ploughea
up, it turns of a reddish BROWN color after a short
time; why is this? p. 233.
A. Because the soil contained a certain compound of iron, called the "pro



DECAYING  VEGETABLES.              403
toxide," which  is black: This protoxide
of iron, absorbing more oxygen from  the
moist air, is converted into another compound, called  the  "per-oxide  of iron,"
which is of a reddish rusty color.
There are two oxides of iron, the one containing more
oxygen than the other. The protoxide, which contains
the least oxygen, is black; the peroxide, which contains the
most oxygen, is ecd. p. 394.
Q.   IWhzy ar-e DECAYING VEGETABLES always
WET? p. 2503.
A.  Because the hydrogen and oxygen
of the vegetables are given up by decay,
and form  into wvater.
Water is comp)osed of the two gases oxygen and hydrogen in the followving protl)ortions: 8 lbs. of' oxygenand 1 lb.
of hydrogen = 9 Ilbs. of water.
N. B. Decaying ve*getables combine into the following
new forms: 1st,'fThc oxygen and hlydrogen form into water: and 2dlly, Tlc, carbon unites with the oxygen of the
air, and produces carbonic acid gas.
Q.   If a house be facedl with STUCCO to resenible
stone, why do's t/It facingl very? oq/len FLAKE OFF in
winter, andl leave the house unsir:htly? p. 333.
A.  Becalse the stucco was not quite
dry; thelefo e, its moisture fi'eezinl( and
expandilng,  tllrusts  the   stucco   away
from  the wall;   and when thle thaw  sets
in, the  stucco  bein(g  unsupported, will
fall by its own weight.
Q.   hTTlhy do the LUSTRES of a CHANDELIER seem
tinted with VAlIOUS brillianC  colors? p. 364.
A.  Because each " drop" of the chan



104-   HORN-GLAZING WINDOWS.
delier is so cut, as to act like a prism:
It decomposes the light, and reflects the
different rapts thereof from its different
points or angles.
Q.  HOaN i.s TRANSPARENT, wAiy are NOT horn
SHAVINGS transparent also? p. 373.
A.  Because the surface of the shaving has been torn and rendered rough;
and the rays of lilght are too much reflected and refracted by the rough surface
to be transmitted through the shaving,
so as'to. produce transparency.
Q.  When a glazier is mending a window, and
cleans the pane with Ahis brush, why do the loose
pieces of putty (on the orPProsIT side of the windowpane) DANCE Up anld downv? p. 142.
A.  When glass is rubbed, electricity
is excited in the parts submnitted to the
friction, and on the part opposite also;
the electricity attracts light substances,
such as loose firagments of putty: As
soon as these fragmnents have touched
the excited part of the glass they become
charged, and fall back again; the ledge
on which they fall deprives them of their
burden, and they then fly up again to
receive a firesh cllare: This process being repeated often, makes the commotion in the loose fiagmfrents of putty, referred to in the question.




INDIAN  RUBBER.                405
A very pretty experiment of a similar kind may be made
thus: Take a common window glass, wipe it quite dry
and warm. and support it on two wine glasses like the
slab of a table: Place underneath the window glass, at the
distance of about two inches, some bran, sand, small pieces
of paper, Dttch gold, pith, &c.: If you now rub the upper
surface of the win-dow glass with a silk rubber, the light
substances beneath will dance up and down.
N. B. The rubber mnay be made thus: Take a common
cork cut evenly and flat, cover it with a piece of silk, and
run a skewner into the upper surface for a handle. A little
amalgam applied to the rubber will greatly improve the
experiment.
Q.   TV7ten yno rub a piece of paper with INDIAN
RUBBER), why is the paper sticky? p. 34.
A.  Because the friction of the Indian
rubber against the  surface of the paper
develops electricity, to which this stickiness is mainly to be attributed.
Q.   If yczt dry a piece of common BROWN
PAPER by tie,.ire and draw it once or twice between
your two IKNEES, s'why will it STICIK fast to the wall?
p. 34.
A.  Because   the   friction   develops
electricity on the paper, which manifests
itself by this property of adhesion.
Q.   Thrhy can noises be HEARD (in a calm day) at
a GREATER DISTANCE on the sea than on land? p. 381.
A. ist —-Because the air over the sea
is generally denser and more laden with
moisture, than the  air over the land  is:
p. 139.
2dly-The density is more uniform:
p. 380, and




106         MOUNTAINS-STARCH.
3dly —Water being more  elastic than
and, is a better propagator of sound.
Q.   The heiAght of MOUNTAINS vlay be ascertained by a BAROMNETER: Explain the reason of this?
p. 383.
A. As we ascend a high mountain,
the quantity of air above us becomes less
and less every step we ascend, and requires less mercury to balance it; in consequence  of which  the mercury  in  the
tube of the barolneterfalls.
If a pile of books be placed on a table, the bottom book
will sustain the most weight, and every book will sustain
less and less, as we get nearer and nearer to the top: The
air somewhat resembles this pile. That on the surface of
the earth resembles the bottom book of the pile; and, as we
ascend a mountain, the quantity of air above keeps diminishing, and the weighl-t to be sustained is in proportion less,
For general practical purposes we may take this for a
rule: for every 100 feet of perpendicular height, the ba.
rometer will fall oi of an inch. If, therefore, the barom.
eter has fallen 1& inch, you know the mountain is 1500
feet high.
Q..How does STARCih assist in giving a smooth
GLAZED SURFACE to LINEN? p. 373.
A. It fills up the interstices between
the threads; and makes the fabric of
more uniform  density.
"Interstices between the threads."-Put your fingers
close, and lay your open hand on the table-a little groove
may be seen, where the fingers divide; these grooves may
be called interstices; and, when we speak of the' interstices of linen," we mean the groove or space between
thread and thread.
Q.   If a DROP of WATER be spilt on a table-clot/
tohy ill it SPREAD in all directions? p. 75.




SALT MEAT.                   407
A. Because the threads of the cloth
absorb the water by capillary attraction.
Q.   V'chy does SALT PRESERVE mealt?
A.  Because it removes the cwater contained in the  animal fibre; absorbing it,
and leaving the meat dry.
The reason stated above is not the sole reason, though
it is certainly the chief one. The following have some in.
fluence also:
2. Salt is composed of chlorine and sodium; the chlorine of the salt takes up the hydrogen of the meat as it is
given off,; and prevents the offensive taste and smell of decay:
3. Brine draws away the albu%'men fiom between the
muscular fibres, which is very subject to putrefaction.
4. The salt unites with the muscular fibre, and makes a
new chemical compound, much less subject to decay: and
5. It keeps the air from the meat, the flies, &c.
Q.   Is SALTED meat equally nutritious as fres]h
meat?
A.   No: Because the albu'men of the
meat is separated  from  the flesh by  the
brine; as well as the alkaline phosphates
and some other substances of great
value.
"Phosphates" pronounce fos'-fates.-Phosphates are
alkaline, and mincral.-ALKALINE PHIOSPHATES are phospho.
ric acid combined with some alkali, such as soda, potash,
magnesia, &c.
" Albu'men of the meat "-a substance like the white of
at, egg, which lies between the muscular fibres of all flesh,
and makes the meat tender.
" The alkaline phosphates of meat" are such as these:
the phosphate of soda, the phosphate of potash, and the
phosphate of magnesia, which are extracted from  the
meat by the acid re-action of the brine.




408             TOUGH MEAT.
Q.   Why is the FLESH of OLD animals rerv
TOUGH?
A. Because it contains very little a1.
bu'nmen, and  much muscular fibre.
Q.  4Why is MEAT always TOUGH, if it be put
into the boiler before the water boils?
A. Because the water is not hot
enough  to  coagulate  the  albumen  between the muscular fibres of the meat,
which therefore runs into the water, and
rises to the surface as a scum.
Q.   Why is MEAT TOUGHII, which has been BOILED
TOO LONG?
A.  Because  the  albumen  beconies
hard, like the white of a hard boiled
egg.
The best way of boiling meat to make it tender is this.
Put your joint in very brisk boiling water; after a few
minutes, add a little cold water. The boiling water will
fix the albu'men, which will pre;vent the iwater from soaking into the meat-keep all the juices in-and prevent the
muscular fibre from contracting. The addition of cold
water will secure the cooking of the intsidc of the joint, as
well as of the surface.
Q.   Why should VEGETABLES be ALWAYS eaten
with salted meat?
A. Because they are all rich in POTASRl, which the brine has deprived the
meat of.
Q.   Why are LAMB and VEAL roore TENDER than
beef and mutton?




MTEAT.                  409
A. Because they contain more albu'men, and less muscular fibre.
Albu'men is a substance like the white of an egg.
Q.   Why do LAMIB and VEAL TAINT more quickly
than beef and mluttlo?
A.  Because   they   contain  a  large
quantity of albu'menii, which is very liable
to undergo putrefaction.
Q.   Why are small birds, such as quails, larks,
partridges, 4c., covered with lard, when they are
roasted?
A. To make them tender and savory.
The covering of lard prevents the savory
constituents  of the  bird   from   evaporatinog with  the  water: in  consequence
of which, the flesh is more tender and
sapid.
" Sapid " i. e. full of flavor.
Q.   Why does inelled wAX become HarD,:when
coed? p. 109.
A.  Because  the  particles  collapse;
and, being packed more closely together,
form  a solid.
The sole difference between a liquid and a solid is thisIn a SOLID the particles are packed more closely together,
than they are in a liquid. The tendency of heat is, to
drive the particlesfutrtAler apart from each other, and thus
to liquify solids.
Q.   Wrhy does PAINT often BLISTER from heat?
A. Because the heat, penetrating
through  the  paint, extracts  some  little
moisture from  the wood, and turns it in18




410           ROTTING LEAVES.
to vapor or steam.  As this vapor red
quires room, it throws up blisters in the
paint, to make room for its expanded
bulk.
Q.   W7hy are ROTTING LEAVES HOT? pp. 60,
253.
A. Because the fermentation of rotting leaves produces carbonic acid gas,
which production is always attended
with heat.  In fact rotting is a species
of slow  combustion.
N. B.-The carbon of the leaves unites with the oxygen
of the air, to produce carbonic acid gas. p. 259.
The new combinations disturb latent heat, and make it
sensible.
Q.  MWy are ROTTING LEAVES DAMP? p. 253.
Answered before, see page 403.
Q.   Why does BREAD become HARD, after it has
been KEPT afew days? p. 153.
A. Because the vapor and gases escape, leaving the solid particles dry; so
that they collapse, and become more solid and hard.
Q.   Wh7iy is NEW BREAD INDIGESTIBLE?
A.  Because the change called "pan'ary fermentation," is not completed.
" Panary " from the Latin  word Panis (bread); " panary
fermentation " means, the fermentation that dough under.
goes in order to become bread.
The sugar of the dough is converted into alcohol and
carbonic acid by fermentation; the dough being adhesive,
prevents the escape of these products, till the mass is




PLANTS -OIL.                411
Maked; when the gas expands, bursts through the mass,
leaving a number of holes or bladders, to show where it
was confined.
So long as the bread is warm, the process of fermentation is going on; and, thercefore, bread should never be
eaten, till it is 24 hours old.
Q.   Why are PLANTS WHITE, which are kept in
the DARK? p. 372.
A. Because chlo'rophyll can be formed only by the agency of the sun's rays;
and it is this peculiar chemical principle,
which gives the green tinge  to healthy
leaves and plants.
Ohlo'rophyll is the green coloring matter of leaves.
Q.   Why does OIL become THICK in WINTERTIME? p. 268.
Ist-Because  it is condensed  by  the
cold, and rendered more solid: and
2dly-Because the  " ste'arine," which
is held in solution  in  warm  weather, is
separated by the action of the cold; and
deposited  as a thick white  almost-solid
matter.
" Stearine " (from the Greelk word Tarap, suet) is the solid
or hard ingredient of all fat, suet, oil, &c. The soft or'iquzd part is called oleine from the Latin word oleum (oil.)
Q. Why is omuttogn FAT, 4-c., solid, and OIL
liquid?
A. Because fat contains a predominance of solid ste'arine; and only a very
small quantity of the liquid oily substance,
called  oleine.  On  the other hand, oil




412    BUTTETR-RAILW'AY WHISTLE.
contains more of tlhe liquid oleine, and
less of the solid matter, called ste'arine.
Q.'/Why is BUTTER IIHAIRD in winter, and soFl
in sumAMERR-time?
A.  Because in \vinter-time the weather is too cold t-) nmeltt the ste'arine, and
the butter is solid; b),ut the heat of summer dissolves it, or holds it in solution
in the oily substance called oleine, and
the butter is soft atjd liquid.
Q.  Why does a rpore-cus make a loud REPORT,
when the paper bullet is dischar/, edfrom it? p. 102.
A.  Because tlhe air. confined between
tile paper bullet and the discharging rod,
is suddenly liberated, and strikes aoainst
the surrounding air; tlis makes a report
irn the same way, ns when any two solids
(such as your hand and the table) come
into collision.
Q.  How does STzEAM r make the whistle of a locomotive engine sound? p. 110.
A.'The whllistle is so constructed, as
very frequently to obstruct the free passage of the steaml  through the jet; in
consequence bf wllicll, very rapid vibrations are caused itn the air, producing the
sharp shrill soulld of the locomotive
whistle.
No sound is ever produced in any sounding body, unlese
there are 12i vibrations in a second of time; if there art




SOUND-WOOD.              413
7680 vibrations, the sound is sharp and shrill; the shrill.
ness increasing, as the vibrations inclrease in number.
Q.  W'hy will BRIGHT lnRON LOSE its POLISH b)
being put into a FIRE? p. 231.
A. Because the oxygen of the air
very readily unites with the surface of
hot iron, and  forms a  metallic oxide;
which displays itself, in this case, by a
dull leaden color, instead of a red rust.
Q.  TVhy does SOUND SEESI LOUDER in CAVES,
than on a plain? p. 381.
A. Because the sides of the cave
confine the sound-waves, and prevent
their spreading; in consequence of
which their strength is greatly increased.
Q.  Whly does PAINT PRESERVE wood?
A. Ist-Because it covers the surface of the wood, and lreveuts both air
and damp from penetrating into the pores:
2dly-Because paint (especially of a
white color) being a bad conductor, preserves the wood of a more uniform temperature: and
3dly —-Because it fills up the pores of
the wood, prevents insects and vermin
from harboring therein and eating up the
fibre.
Q.  Why does UNSEASONED WOOD DECAY much
more rapidly than wood well seasoned?
A.  Because the albu'men which the




Mf4         KMOTUER OF PEARL.
sap contains, p)roduces a species of fermenltation; duritg vwhich, the cel.l'lllir,
and ligneous rmatter of the  wood  are
turned into carbollic acid and wa/ter.
"Albu'men," a substance resembling the white of an
egg.
"Cellulin," the substance which composes the cells of
wood, aJ wax composes the cells of a honey-comb in a
bee-hive.
"Ligneous matter," or vegetable fibre, is the hard or
woody part of wood.
Q.  WTThIy is wOOD placed in a stream of running WVATER to SEASON it?
A. - Because the running water washes away the sap; and thus prevents fermentation and decay.
Q.   Why will solutions of salts PREVENT the
DECAY of wood steeped thercin?
A. Because the salts unite with the
albu'men of the sap, coagulate it, and
prevent fermentation.
Q.  lWVhy does MOTHIER of PEARL show so many
colors? pp. 364, 370.
A.  Mother of parl consists of a vast
number of very tlhil half-transparent layers of unequal tlliclrness, over-lapping
each other like the scales of a fish.
Where these layevcs terminate are very
small grooves or strealks running in all
directions, which act like prisms.
It is these strcakingl's or grooves, which




WATER  IN  A GLASS.               415
cause the various and changing colors of
mother of pearl.
The same thing may very easily be imitated, and is
frequently done in what are called "iris ornaments." first
invented by John Barton, Esq., of the Royal Mint. These
iris ornaments are made of steel, and have about 30.000
grooves per inch; they are used in court dresses, for but.
tons, sword handles, &c., and are very brilliant indeed.
Mother of pearl may be also imitated by taking inpressions of it in bwax, balsam of tolu, isinglass, or gum; these
impressions will exhibit all the shades and colors of mother
of pearl, merely because the impression will be streaked
or grooved in a similar way.
Q.   WIrhy can you fill a DRY GLASS BEYOND the
level of the brim? p. 206.
A.   Because the mass of water in the
glass  holds the  overplus back, by  the
power of attraction.
Q.    ~t7ty/ will the over?plus instantly flow over,
if the edges of the glass are wet?
A.   Because  the  water on  the  edfge
of the glass has an affinity to the water
towering above it, no less than the water
in the body of the glass has; and in this
state of equilibrium  the force of gravity,
acting on the elevated particles of water,
causes thenm  at once to fall over.
Q.   If you leave a little tea in your cup, adl
rest your spoon on the bottom of the cup, why does the
TEA RUSII to the SPOON? p. 387.
A. Because the spoon attracts it, by
what is called, capillary attraction.
The sloping spoon makes with the sides or bottom of
the cup a space in the shape of a very small wedge,; where




(16          LUCIFER  MATCHES.
the aperture is small, the cup and spoon draw the tea up
by the force of attraction; and the narrower the opening,
the stronger the attraction.
Q.   WTIhen LIQUOR is decanted or pouredfrom 4
bottle, -why does it GURGLE? p. 256.
A.  This bubbling  noise  is made by
the air bursting into the bottle, and the
liquor bursting oult.
The liquor, filling the neck of the bottle, prevents the
air from getting fieely in; and the air, pressing against
the mouth of the bottle, prevents the liquor from getting
freely out: in consequence of wlhich, the air bursts into
the neck of the bottle, and the liquor runs firom the same,
by fits and starts, as either is able to prevail: as this process is repeated, the noise produced is called a gurgle.
Q.   Why will LUCIFER  MATCHES IGNITE by
merely drawing them  across any roug/h surface?
pp. 99, 221.
There are two sorts of lucifer matches; those that ignite
silently, and those that ignite with an explosions.
A. SILENT LUCIFERS are made of
phosphoruzs, which has an affinity to oxygen at the lowest temperature; insomuch  that  the  little  additional heat,
caused by the friction of the matclh across
the  bottom   of the  lucifer-box, is sufficient to ignite it; and, at the salne time,
to  ignite  the  sulphur with  which  the
match is tipped.
EXPLOSIVE LUCIFERS are made of
chlorate (f potash, which will c.xp)ldle by
very slight friction, and produce combustion.




MIRRORS.                  417
" Chlorate of potash" is a compound of chloric acid
and potash. Chloric acid is a compound of two gases,
chlorine and oxygen.
Q.  IWhy will not lucifer matches ignite, if they
are DAMP? p. 48.
A.   lst —Because  the cold, produced
by the evaporation of the water, neutralises the heat produced by the fiiction of
the match across the bottom of the lucifer-box: and
2dly-Because the damp prevents the
free accession of oxygen to the match,
-without which it cannot burn.
Q.   When our likeness is reflected in a lookingglass, the entire image is REVERSED; SO that our
RIGHT cheek is the LEFT cheek of the reflection, 4yc.;
why is this? p. 345.
If a person stands opposite to us, his position in regard to
the cardinal points of the compass is altogether reversed.
As in a mirror all the lines and ancles
of incidcence  equal the lines and angles of
reflection, it is manifest that those  parts
of the person which are nearest the mirror, will seen  to be nearer than  those
more  remote;  but, if our  right cheek
were to cross over to the right cheek of
the reflection, then this law would be
broken.
Our right cheek would cross over to the right check in
the mirror, and our left to the left, 3XA in which (without doubt) the extreme points of the diagonals A A, and
B B, are further apart than A is from B.
18*




418        PAPER CURLING, ETC.
Q.  A SILVER tea-spoon becomes iorIn 1HEATED
by hot tea, than one of INFERIOR metal (as German
silver, lNickel, 4-c.); why is this? p. 156.
A.  Because silver is a better conduct.
or than German silver or Nickel.
The three best conductors of heat are, i. Gold, 2. Silver,
8. Copper.
Q.  If you scrape a slip of paper with a knife,
why will the PAPER CURL?
A.   Because the under surface of the
paper is cnltracted by the scrapingr, which
brings the particles closer together; this
contraction  of the under surface bends
the slip of paper into a curl or arch.
Q.  Wlhy does the STOPPLE of a decanter STICK
fast, if it be put in damp?
A. If the stopple be damp, it fits the
decanter air-tight; and if the decanter
was last used in a heated room, as soon
as the hot air inclosed in the inside has
been condensed by the cold, the weight
of the external air will be sufficient to
press the stopple down, and make it stick
fast.
Q.  Wthy does the STOPPLE of a SMELLING-BOTTLE very often STICK fast?
A.  Because the contents of a smelling-bottle are very volatile, and leave the
neck of the bottle, and the stopple,
damp.
If the smelling-bottle was last used in




DECA~ ING  VEGETABLES.             419
a hot room, as soon as the hot air and
volatile essence, inside the bottle, lhave
been condensed by the cold, the weight
of the external air will be sufficient to
press the stopple down and make it stick.
In the last two instances, the pressure of air forces the
stopple down too far, so that it is like a cork which has
been forced into a bottle: Hence there are two mechanical forces to contend against; 1st, The weight of air on
the stopple which holds it down, as an exhausted receiver
is held tight on the plate of an air-pump: and 2dly, The
neck of the bottle, (expanded by heat when the stopple
was put in,) will girt it with great pressure, so soon as it
is contracted again by cold.
Q.   Decaying vegetables are first of a brownish
tint, why do they afterwards turn of a DEEP BLACK?
A. Because the hydrogen of the decaying vegetables is separated from the
mass by the process of decay, and leaves
a larger proportion of carbon behind.
Vegetable fibre contains 652 per cent. of carbon.
When partially decayed  64  "
When black with decay 66 " " " "
Q.   Why is an  OAK  STRUOK  by LIGHTNING
more frequently than any other tree?
A. Because the grain of the oak,
being closer than that of any other tree of
equal bulk, renders it a better conductor.
It is said, that the sap of the oak contains a large quantity of iron in solution, which impregnates the wood and
bark. thus increasing its conducting power.
Q.   Why does a LOBSTER, which is black while
Zlive, turn RED by being BOILED?
A.   The blackness is due to a peculiar




420         BOILED  SHRIMPS,  ETCc
coloring matter secreted by the lobster;
which, however, turns red when exposed
to the heat of boiling water.
Q.   Why does a sHrIrMP, which is nearly WHITE
while alive, turn rED by being BOILED?
A. The delicate pinky whiteness is
due to a peculiar coloring matter secreted  by  the  shrimp;  which, however,
turns red  when   exposed to the heat of
boiling water.
Many coloring matters pass into each other under very
slight changes of condition. g. e.
Blae indigo changes to white indigo, if only one atom
more of hydrlogen be added. So also, the green chlorophyll
of leaves changes into the infinite hues of the petals of
flowers.
The science of colors is not at present sufficiently understood to give very lucid explanations of these changes;
the facts are known, and little else besides.
Q.   Wh:ay is the SIHADOW  of the MCooN stronger
than the shadow of the sun?
A.   Because the light of the moon  is
not so strong as the light of the  sun; in
consequence of which, the dispersed and
reflected rays of the moon cannot reduce
the opacity of shadows so much, as the
more intense  rays of dispersed  and  re.
flected daylight.
"The opa'city of shadows," i. e. the darkness of shadows.
Q.   Why does HARTSHORN take out the red spot
in cloth, produced by any AcID?
A.  Because  hartshorn  is an  alkali




POWDERED SULPHUR.                 421
and the peculiar property of every alkali
s to neutralize acids.
" Alkali" pronounce Al'-ka-li. Soda, potash, magnesia,
&ec., are alkalies.
Upon this principle effervescing drinks are made of a
carbonate of soda (an alkali), and citric or tartaric acid.
Effervescence is produced, by the giving off of carbonic
acid during the process of neutralization.
N. B.-The carbonic acid is made from the carbon (of
the carbonate of soda) combining with the oxygen of the
acid. p. 43.
Q.   Why will rPOVDERED  SULPHUR QUENCH
FIRE more readily than water?
A.   Ist-Because  powdered  sulphur
has a very strong affinity for oxygen, and
converts it into sullh aurows acid; as this
is the case, the fire is deprived of
its essential food (oxygen), and is, in
fact, starved out: and
2dly-Because sulphurous acid throws
off dense whitefuwnes, and surrounds the
fire with an extinouishing atmosphere.
The difference between sulphurous acid and sulphuric
acid is this: sulphurons acid contains less oxygen than
sulphutic acid. When we burn sulphur in air, it throws
off suffobecating white fumes, called sulphurous acid.
Q.   How does STARCHi STIFFEN linen?
A. By filling the interstices of the
fabric with a solution of starch, by which
means the linen is made more rigid.
Q.   Why  should  LIGHITNNG-CONDUCTORS  be
POINTED? 
A.  Because points conduct electricity




422       BRICKS-POTATOES, ETC.
away  silently  and   imperceptibly:  but
knobs produce an explosion, which would
endanger the building.
Points empty the clouds of electricity, acting at a much
greater distance than knobs; thus a Leyden jar of considerable size may be safely and silently discharged, by holding the point of a needle an inch or two off.
Bladcs of grass, the ears of corn, and other pointed objects, serve to empty the clouds of their electricity.
Q.   Why do BRICKS turn GREEN, after they
have been exposed to the weather?
A. The "green" is a moss or lichen,
which grows on the bricks; the seeds of
which were carried to the surface by the
winds.
Q.   When POTATOES are boiled, why are those
at the TOP of the boiler COOKED SOONER than those
nearer the fire?
A.  1st-Because the hottest particles
of the water rise to the top of the boiler,
and the coldest particles sink to the bottom: and
2dly —Because the top of the boiler is
always enveloped with very hot escaping steam; in consequence of which, the
potatoes on the top are subjected to more
intense heat, than those at the bottom of
the boiler are.
Q.  If a SILVER SPOON. which has been tarnished
by an EGG, be rubbed with a little SALT, why will the
tarnish disappear?
A.  The tarnish in this case is sitlphwtt




SOUR MILK, ETC.            423
ret Gf szlver, produced by the sulphur of
the egog combining with the silver spoon.
Salt acts upon this sulphuret of silver
thusThe sodium of the salt combines with
the sulphur, and produces sulphate of soda.  The sulphur being thus taken away
from the silver, the tarnish disappears.
" Sulphuret of silver," i. e. sulphur in combination with
silver.
Salt is a compound of the metal called sodium, and tho
gas called chlorine.' Sulphate of soda" is a combination of sulphuric acid
and soda.
Q.   Why are BOOKS discolored by AGE or
DAMP?
A. Because the fibre of the paper
becomes partially decomposed, and various impurities firom the atmosphere (or
other sources) become mixed with it.
Q.  /Why does soUr MILK CUrIDLE?
A. Milk consists of five ingredients:
1, Ca'sein or curd; 2, Butter; 3, Sugar;
4, Water; 5, Certain Salts.
The Ca'sein or curd of sweet milk is
like  the white of an egg before it is
boiled; but the casein or curd of sour
milk is like the white of an egg after it
is boiled.
This casein or curd of milk is coagrulated by acids:-When milk is sour, the




424              MILK SOUR.
lactic acid of the sour milk, mixir.g with
the casein, coagulates it; in consequence
of wlhich, it separates  from  the  water
and  becomes an insoluble  mass; or (in
other words) the milk curdles.
1' Lactic acid " (from the Latin word Lac, milk) is the acid
of sour milk. But it is found in several other substances
also, as in the fermented juice of beet-root, turnips, carrots, rice-rwater, tanning bark, &c.
Q.  W- hy does MILK turn soUR by KEEPING?
A.  Because it undergoes a fermentation; during which " lactic acid" is
formed, which turns the milk sour.
The lactic acid is formed from the sugar of milk by fer.
mentation.
Q.   TWVhy does MILK turn soUR in HOT weather;
much sooner than in cold?
A. Because heat very greatly accelerates the process of fermentation; during which  lactic  acid  is formed, which
turns the milk sour.
Q.   Why can you NEVER BOIL STALE MILE
without curdling it?
A. Because stale milk is in an incipient state of fermentation, which the heat
of the fire greatly accelerates: Tie lactic acid which is formled during fermenetation, mixino with the casein of the
milk, coaoulates it.
Casein ( prnoun7ce cas'-e-in) is the curd of milk coagia
latedl by acids only.
Q.   Why does RENNET CURDLE MILK?




CREAM, ETC.                  425
A.  Because  it converts the sugar  of
milk into  lactic acid, which  mixes with
the casein and coagulates it.
Milk contains soda and potash; so long as these alkalies
are combined with the casein of the milk, the compound
is soluble in water, and the milk sweet: but when the
acid deprives the casein of the alkalies by combining with
them itself, then the casein is no longer soluble in water,
but is precipitated or curdled.
Rennet is the prepared inner membrane of the stomach
of a calf- so called from the Germlan word rinLe1 (to
curdle.)
Q.   W4zy does CHURNING cream  convert it into
BUTTER?
A. Cream is the fat or butter of
milk, contained in little globular cases of
albu men:
By   churning,  this  film   or  envelop
of albu'men is broken, andt the butter ot
fat set free.
The globules are invisible to the naked eye, but may be
distinctly seen floating about milk, by a tolerable micro.
scope.
Albu'men is a substance resembling the white of an egg.
Q.   Il'rhy does the SUN or fire WAnr WOOD?
A.   Because heat draws out the moisture  from   that part of the wood  whlich
faces it, and causes the heated surf:ace
to shrink; as, therefore, the  heated surface of the wood sh7rinks, and is smaller
than the other surface, it draws it into a
curve, and the wood is warped.
Q.   IWhyt does the SUN, for the most pa7t, rAwT
artificial COLORS?




426.       KNIVES-DOUIGH.
A. Generially, the loss of col(,r arises
from the oxidation of the substances used
In dyeing; as tarnish and rust are an oxidation of metals.
Sometimes, however, the ingredients
of the dye are otherwise decomposed by
the sun; and the color (which is due to
a conmbination of ingredients) undergoes
a change, as soon as the sun deranges
or destroys that combination.
Q.  Hthen a KNIFE is sharpened on a GRINDSTONE, wh/ is OIL or water used?
A. To make the contact more perfect.
The oil or water fills up the interstices
of the rough stone, and makes a more
uniforln surface: In consequence of
which, the entire edge of the blade is suhmitted to an equal portion of friction,
which would otherwise be rough and
uneven.
Q Wfhy does BAKING dough convert it into
BREAD?
A. When flour is baked in an oven
its starch is changed into a g'lnt called
destrin: and
A similar change is produced upon
the farinaceous portion of the dougyh.
The yeast (added to the douglh) converts
part of the starch and sugar into alcohol
rV~\  - rlv~VIL —~  rrn h~r




MOULDY BREAD.                  427
and carbonic acid: Of these, the alcohol
evaporates in the oven, and the carbonic
acid forces the dough into bubbles, in its
effort to  escape, rendering  the  bread
light and full of eyes.
In 100 lbs. of bread, and 100 lbs. of dough, we have
STARCH.     SUGAR.   DEXTRIN.
In dough,      68 lbs.     5 lbs.     0=100
In bread,      53" i  "              18=100
wherebv it will be seen that 16j lbs of starch have been
converted into the gum called dextrin by baking.
Dextrin is a gummy matter similar to that which composes the cells of wood (called cellu'lin), only it is soluble
in cold water.
Diastase (pronounce di-as'-tase) is a peculiar vegetable
principle of malt extracted by water, which converts starch
into dextrin or sugar.
Q.   Why does BREAD become mouldy, after it
has been KEPT a few days?
A. Because spores of the mould fungus, floatilg  in tile air, fix thcmsclvcs   in
the  decaying bread and germinate.
Fungi germinate only in decaying, bodies.
Spores (one syllable) or Sporules (two syls.) from the
Greek word arropa (seed) is a word used by botanists to indicate the seed of cryptogamic or flowerless plants. They
differ from seeds in this respect, every part of the spore
shoots into a plant, and not one particular point alone, as
in common seeds.
Q.   Why does MEAT PUTREFY sooner in hot,
DAMP weather, than in cold?
Putrefaction is simply the decomposition of the original
elements, and their reunion in a new order. The new order
is as follows:
1st. Carbon and oxygen unite to form carbonic acid;
2dly. Hydrogen and oxygen" "  "    water;
Hdi'/. Hydrogen and nitrogen "    ammonia.
N. 1. —Carbon unites with oxygen with a readiness pro




428           PUTRID MEAT.
portioned to its heat: When red hot, the cGmbinati.)n i
most readily effected.
The reason  why  meat taints more
rapidly in hot weather than cold, is this;
Because the carbon of the meat unites
with the oxygen of the air more readily
when hot than cold: and
The reason why damp aids putrefac.tion is this; Because the clamp, deposited on the surface of the  meat, is of
itself one of the compounds of putrefaction, and leaves an excess of hydrogen
in the meat: and
Thus the original proportions and combinations of the meat are altered and decomposed.
The chief reason why salt preserves meat is because it
absorbs tile water from it, and deprive.: it of hydrogen.
Q.  V/hy does MEAT rUTRErI'  most rapidly iM
very CHANGEABLE weather?
A.  Because moisture is more freely
deposited on the meat in very changeable weather; and  this inoisture is a
chief compound of putrefaction.
Q.  BIRaDS, after they are killed, KEEP longer iu
their FEATHERS, than when they are plucked; why is
this?
A. Because the feathers prevent tlhe
air or damp from  getting so readily to
the bird, to produce fermentation or des
cay.




PLANTS-INDIAN-RUBBER.             429
Q.  lWhy do PLANTS, which are kept on a wmtb
dow, BEND to the GLASS?
A.  Because the side acway from  the
lioht grolvS facster, than  the side facirng
the light, and pushes the top of the plant
over in a curve.
Wood is warped by the fire, because the under surface is
smaller than the upper.
And paper is made to curl by scraping the under surface
with a knife for the same reason.
N. B. —Woody tissue is deposited in the stem most
abundantly on the side nearest the liglt; and where wood
is formed most., growth is slowest, because the part is less
succulent.
Q.   Why does INDIAN-rtUBBEIt erase PENCIL
MArKS from paper?
A. Indian-rubber contains a very
large quantity of carbon: Black-lead is
carbon and iron.
Now, the carbon of the Indian-rubber
has so great an attraction for the blacklead, that it takes up the loose traces of
it left on paper by a pencil.
Q.   Why does WATER ROT WOOD? and why
does AIR rot WOOD?
A. Because it converts the solid part
of the wood into what is called humus,
by oxidation; thus1st-The carbon of the  wood  is oxidised into carbonic acid; and
2dly-The  hydrogren of the wood is
oxidised into water-the residue becomes humus or mould.




130        WATER-HOT IRON.
"Humus," pronounce U'-mus. The black mould of our
gardens is called humus, and is produced by the decay of
vegetable matter by the action of air and water.
Q.  Why does WATER make a HISSING noise,
when it is poured on FIRE?
A.  Because the part which comes in
contact with the hot coals is immediately
converted into steam; and, as it flies upward, meets other particles of water not
yet vaporised; the collision produces
very rapid vibrations in the air, and a
hissing noise is the result.
Q.  Why does HOT IRON make a hissing noise,
when plunged into WATER?
A.  Because the hot iron converts into
steam the particles of water, which come
in immediate contact with it; and, as
the steam flies upwards, it passes by
other particles of water not yet vapo.
rised: the collision produces very rapid
vibrations in the air, and a hissing noise
is the result.
Q.  Wthy will HOT IRON BEND more easily th'mz:old?
A.  Because it is not so solid.  The
particles are driven further apart by heat,
and the attraction of cohesion weakened;
in consequence of which, the particles
can be made to move on each other more
readily.
By a still further application of heat: the particles wiL




HEATED  IRON, ETC.               431
be driven so far asunder from each other, that thle solid
iron will liquefy: in which state the particles will move on
each other almost without resistance.
Q.   Why does IRON turn first RED and then
VIIITE from  HEnT X
A. Light and heat depend upon vibrations; the more rapid  the vibrations,
the  more  intense the  light and  heat;
White heat is a more intense decree of
heat than red, and occurs only when the
vibrations are most rapid.
Candescence occurs when bodies are heated to 800~
It begins with a dull red color, passes to an orange tiht
and ultimately to a shining white.
The more perfect the combustion of carbon the whiter
its color.
Probably these varying colors depend upon some variety
in the thickness of the molecules of the heated substance,
caused by the influence of heat; whereby it is made to
reflect different colors according to the varying thickness
of the molecules. But the subject is not well understood
at present.
Molecules (pronwunce mo-le-cules) are very small particles of matter in a mass. ATOMS have no regard to
aggregation.
Q.   Why does WATER  FREEZE more quickly
than MILK?
A.   Because milk contains salts in solution; in consequence of which, it requires a greater degree of cold to congeal it than water.
Water freezes at 32~, but salt and water will not freeze
unless the thermometer sinks below 7~.
Q.   WIhy does HOT WATERI FRtEZE  more quickli
Man cold?
A.  Because there is a slight agitatiron
0     0




432        OIL-FREEZING  WATER.
on the surface of hot water, which pro.
motes  congelation;  by   assisting   the
crystals to change their positions, till they
take up that which  is most favorable to
their solidification.
Other causes may have aminor influence, as for example:
In hot water, the particles are subdivided into smaller
globules by the heat, and offer less resistance to the action
of cold than larger ones. 2dly. The air has been expelled
from the water by the process of boiling-hence the Indians always used boiled water in their ice-pits.
N. B. -Air must be expelled from water before it can be
frozen.
Q.   Why will a little OIL on the surface of
water prevent its FREEZING?
A. Because oil is a bad conductor,
and prevents heat from leaving the water.
The surface of water never freezes, till the whole mass
is cooled down to 42~.
Q.   Wh7y does water in a very EXPOSED place
freeze more rapidly than that which is under cover,
or in places less exposed?
A.   1st-Because evaporation goes on
more rapidly, when water is exposed;
and carries away heat from the general
mass: and
2dly-Any  covering will radiate heat
into the water below, and prevent the
mass from  cooling down to 42~.
"Radiate heat" means, to send heat out in rays.
Q.   Why are GLUE, GUM, STARCH, and PASTE,
adhesive?




RAIL-WAY TRAIN) ETC            433
A.  Because  the  water used  with
them rapidly evaporates, and leaves them
solid.
They lose their adhesiveness when dissolved in water;
and, therefore. inust always be suffered to become dry,
before they will lhold with tenacity.
Q.  TWrhy does a rail-way TRAIN make more
NOISE, when it passes over a BRIDGE or MEADOWS
than whern it rutns over SOLID GROUND?
A. Because the bridge (or meadow)
is very elastic, and vibrates muchl more
from  tile we'ak' of the train, than the
solid earth; in consequence of whlich, it
produces more definite sound-waves.
The bridge acts as a sounding-board; and the water or
earth, below the bridtge, repeals the sound.
Q.   Why does MILK BOIL more QUICKLY than
water?
A.  Because less steam  is carried off
from  the thick liquid (milk), than from
the thin liquid (water); in consequence
of which, the heat of the whole mass rises
more quickly.
Q.   Why twill MILK BURN very easily, when
boiled, while water will not do so?
A. 1st-Because milk contains solid
organic substances, capable of burning;
which water does not:-and
2dly-Because  the  heat of the  fire
coagulates  the  albu'men  of  the  milk
19




434          WAX —STEEL,  ETC.
which  falls to the bottom, and adheres
to the boiler.
Albu'men is a substance resembling the white of an egg.
Q.   I f7y does WAx become SOFT, before it turns
LIQUID?
A.  Because it absorbs heat sufficient
to loose, the contact of its particles,
before it has absorbed sufficient to liquefy
the mass.
Q.  If you heat STEEL RED IIOT in thefire, and
then plunge it suddenly into cold water, it becomes
HARD and BRITTLE; why is this?
A. Because the sudden chill violently
expels  the  latent heat, which  would
have settled in the steel, had it been allowed to cool slowly.
The malleability and toughness of metals depend upon
their power of absorbing heat.
Q.   W7Wy are the ICE-PITS of India lined with
straw and coarse blanketing —stopped up with STRAW
at the mouth, instead of a door-and TIHATCHED On
the roof, instead of being covered with slates or tiles?
A. Because straw and coarse blanketing, being very bad conductors indeed,
prevent the external heat from getting
to the ice-pits to dissolve the ice.
Q.  How do the natives of INDIA provide them
selves with ICE, when the temperature is much higher
than the freezing point?
A.  They make a hole in  the  earth
about 2 feet deep, and 30 feet square:
They cover the bottom of this hole, to




WARM COUNTRIES, ETC.           435
the depth of a foot, with the stalks of
Indian corn or sug'ar-canes:
On this bed they place fleet unglazed
earthern pans about an inch and a quarter deep, and pour into them (at sun-set)
soft water, which has been boiled and
suffered to cool. At sun-rise the water
is found to be frozen, and is thrown into
the ice-pit.
The reason of this is: The vessels being porous, part of
the water evaporates through the pans, and reduces the
heat of the water sufficient for congelation.
Q.  Why is it customary, in very HOT COUNTKRIES, to sit in rooms separated by CURTAINS, instead
of'walls; and to keep these curtains constantly
sprinkled with WATER?
A. Because curtains are bad conductors of heat; and the rapid evaporation
of water reduces the temperature of the
room  10 or 15 degrees.
Q.   WV>hy is it impossible to WRITE on GREASY
PAPER 2
A. Because grease has no affinity for
water or ink, and, therefore, will not mix
with it.
Q.  Wf/hy is rain said to "bring down the
rold?"
A.  Because the change in the atmosphere, which causes rain to fall, sets free
latent heat, and makes it sensible.




136           TURPENTINE, ETC.
Fro.st is broken up by the rains; and the sharp, piercing
wind, being laden with vapor, is much mitigated.
Q.   TWihy does TURPENTINE  take out GREASE
spots from cloth?
A. Because it dissolves fixed oils.
Thefived oils are all greasy oils, such as spe:rm oil, olive
oil, &c. The other sort of oils, called vwltatile or essential
oils, are those used in perfumery, &c.
Q.   Why does OXALIC acid lake oust INK spots?
A.   Because it dissolves the tannate of
iron, of which the black portion of the
ink consists.
" Tannate of iron " is tannic acid combined with iron.
Tannic acid is the acid of tan, or oak bark.
Q.    thcn COPPER is exposed to moist air, it is
incrusled with a green coatintg, called VEr.DIGRIS;
why is this?
A.   Because the  oxygen of the moist
air combines with the copper, and forms
what is called a hydrate of tile carbonate
of the protoxide of copper.
" Protoxide " (wrpcarog-oxide, the lowcst or first state of
oxidation): The protoxide of copper is a comnlination of
ane poftion of oxygen, and one of copper. IIydrate (from
the Greek word vdcp, water) is a compound containing
water; but in all hydrates, the sub.,stance forms so intimate a union with water, as to soliditf it, and render it a
component part. A " hydrate of the carbonate of copper,"
is a compound of water, carbonic acid, and c!,per; and
"A hydrate of the carbonate of the protoxide iof copper,"
is copper in its lowest state of oxidation, in wb:i:h1 carbonic
acid and water is so united, as to forml  a solidi.
Q.   IVhy does ZINC TARNISHI in the evr?
A.   Because the oxygen of' the moist
air combines with the zinc, and forms an
oxide of Zilnc.




SALT-SILVER.                437
An " oxide of zinc " is oxygen in union with zinc.
Q.   Why does SALT turn silver BLACK?
A. Because it precipitates an oxide
of silver on the surface of the spoon, the.
color of which is black.
" Marking ink" is made of soda and the nitrate of silver; the black mark being due to the oxide, precipitated
on the cloth.
Q.  How can the BLACK stain of SILVER, made
by salt, be REiMOVErD?
A.  By washing  the  silver in hartshorn, or common  ammonia; by  which
means, the oxide will be re-dissolved
and the blackness entirely disappear.
Q.   Why does WAXING cotton or thread make it
STRONGER?
A.  Because it cements the loose filaments to the cord; and makes the strands
of the thread more compact.
The " filaments of the cotton," are the loose fibres hanging about it. The " strands " are the twists or single yarns.
twisted into a thread. Sewing cotton contains two, three,,
and occasionally more than three strands.
Q.   The cronmb of twalking-sticks is made byBOILING the end of the stick, and then bending it,
into an arch; why is a STICK made FLEXIBLE hby
BOILING?
A.  Wood contains many substances
soluble in hot water, as starch, sugar,
gum, &c., and several other substances
which are softened by it: as, therefore,.
several substances are dissolved, and




188            MANURE-GUANO.
others softened by boiling water, the stick
is rendered flexible.
Cell'ular fibre and woody matter, when boiled in water,
become soft and gelatinous.
Q.   Explain how  MANURE makes LAND Fnr.
TILE.
A.  As plants extract a certain amount
of salts firom  the soil, whiclh arle entirely
removed at harvest, it is obvious that the
soil will become gradually imnpoverished,
unless these  matters are  restored; this
restoration  is  made  by   flanuraiug  the
soil.
Q.   WIhy is GUANO valuable as a MANURE?
A.  Because it contains nitrogen  and
ammonia, both of which are essential to
plants.
Q.   XTIhat is th/e use of LIME, MARL,   -C., as
MANURE?
A. 1st-They decompose vegetable
substances: and
2dly-They  liberate  the  alkalies  in
union with the silica of the. soil.
Silica (proownce Sil'-i-cah), from the Latin word Silex,
flint-one of the most common substances on the earthcontaining the following varieties-wlhite chuckystoneviolet amethysts-red quartz-yellowv cairngormiul-Brazil
pebbles for spectacle glasses —rock crystal-chalcedonyagate-bloodl-stones-cornelian-flint, &c.
Q.   TI/,hy do you see the reflection of Two candies, or tiwo fires, in a looking-glass or wilidowu-pane,
though there is only ONE candle or fire in the room?
A.  Because each surface of the look



WKY  BLUE-LIGHtT.               439
ing-glass or window-pane makes a reflection.
N. B.-In order to see these two reflections, you must
not stand directly before the glass, but a little on one side.
Q.  WThy is the siY BLUE on a fine day, and
not red or orange?
A.  Because the momentum  of red and
orange rays (being greater than that of
blue) causes them  to penetrate  beyond
the clouds; but the blue rays are stopped on their passage, and reflected.
Q.  TWh7y is it LIGIT when the heavens are
covered wuilh thick CLOUDS?
A.  Because the multiplied reflections
of the sun in the atmosphere  are sufficient to give light upon  the earth, even
when thick clouds are passing  over the
disc of the sun.
Q.   IVhy are put Irefyi g FIS}IT LIUaITNOUS? p. 266.
A.  Because the carbon  of the fish,
uniting witll oxygen, forms carbonic acid;
and  tlle Vphosphoric acid of the fish (being  tlhus deprived  of oxygen)  is  converted into pIWhoshorltts: as soonl as tlhis is
the case, tlhe pllosphorus begins to unite
with the oxy'gen of the air, and becomes
luminous.
Carbonic acid is a compound of carbon and oxygen.
Phosphlloric acid is a compound of' plos)horus and oxygen. If you take the oxygen avay frio  phosphoric acid,
the residue, of course, is phosphorus.




440            SEA LUMINOUS.
The luminousness spoken of is due to the slow comns.
lion of the phosphorus, while it is uniting with the oxygen
of the air.
Q.   Why is the SEA often LUMINOUS in summer.
time? p. 266.
A. Because the small jelly fish decay;
the phosphoric acid which they contain
(being deprived of oxygen) is converted
into phosphorus, unites with  the oxygen
of the air, and becomes luminous.
Q.   TVhFat causes the disease commonly called
the itch?
A. It is produced by an insect called
the "itch  insect," which burrows in the
skin, and is greatly encouraged by filth.
Sul Dour, corrosive  sublimate, &c., will
des -roy the insect, and cure the disease.
Co, rosive sublimate is made of 200 parts of mercury
fvith 72 of chlorine. It is plain to see how the disease is
contagious.
Q.   Why does the use of SALT BEEF produce
scurvy?
A.  Because the soluble salts are removed from  the beef by brine: in consequence of which, it cannot restore to
the human system  those salts, which are
essential to preserve the blood in a
healthy state.
Q.   WILhy is LIME-JUICE a perfect CURE for
ECURVY?
A. Because it contains the very salts,




VEGETABLES-WVOOD.                441
removed firom  the beef by  the action of
orine.
Namely-alkaline phosphate-and sulphate, chloride
and phospllate of lime.
"Alkaline plhospllates "   are such as these-phosphate
of soda, phosl)liate of potash anD( nhosphate of magnesia;
i. e. soda, potash, or magnesia, in combination with phosphoric acid.
" Sulpllate of lime," a compound of sulphuric acid and
lime.
"Chloride of lime," a compound of chlorine gas and
lime.
"Phosphate of lime," a compound of phosphoric acid
and lime.
Q.   T7iry does the use of VEGETABLES generally
PREVENT SCURVY?
A.   Because they contain  the soluble
salts removed from   the beef by  brine;
which being restored by the vegetables,
preserve the blood in a healthy state.
Q.   lT7tL/ does wOOD DECAY 2
A.  Because  the  oxygen  of the  air
unites \with the  carbon and hydrogen of
the  wood, and  forms carbonic  acid  and
water.
Q.    WV/ten WINE is spilt on a TABLE-CLOTH,
napkin, or handkerchief  how  can the STAIN  be
REMOVED?
A.   By  dipping it in a weak  solution
of chlorine.
Bleaching powder is only lime impregnated with hlo.
rine.
Q.   [Vhen WINE is spilt on a table-cloth, 4-c.,
19*




442         INFECTIOUS DISEASES.
why do persons generally cover the part im;nedzatel5
with SALT?
A.   Because  salt is  a  compound  of
chlorine and sodium; and the chlorine of
the salts acts as a bleaclhing powder.
Q.   WThen INFECTIOUS DISEASES prevail, hom
can the contagious matter be removedfront bed-roomns,
hospitals, houses, d4.?
A. By using a solution of chlorine, or
of sulphurous acid; which will not only
remove  the  contagious matter, but also
the offensive smell of a sick room.
Q.   Hrhat is an excellent remedy against RATS
and MICE?
A.   Sulphuretted hydrogen.   All that
is necessary is to introduce the beak of a
retort into a rat-hole, while sulphuretted
hiydroglen is being given off.
It will destroy the rats and make the hole unfit for
others to frequent.
Stldplhrelted hydrogen is made thus. Put into a retort
or glass bottle a quantity of sulphuret of iron, prepared by
healtiqh  a rod of iron red hot; bring it in contact with a roll
of sulphur-allow the sulphuret of iron formed to drop
into water; pour over it a small portion of water, and
then add an equal quantity of sulphuric acid; sulphuretted
hydrogen will be given off most copiously.
Q..   WhLy does GUNPOWnDER EXPrODE?
A.  Because of the instantaneous production and expansion of carbonic acid,
sulpllurous acid, and nitrogen.
Gunpowder consists of 76 parts of nitre, 13 charcoaL
and 11 sulphur.




SHADE, ETC.                443
Q.  An object in the SHADE is not so bright
and apparent, as an object in the sun; twhy is it
not?
A. Because objects in the shade are
seen by  reflected light reflected, i. e. the
light is twoice reflected: and, as the rays
of light are always absorbed in some
measure by  every  substance on which
they fall, therefore, some light is lost;
1st-Befcre the second reflection is made,
and 2dly —In  the object that makes the
second reflection:
Part of the rays are absorbed, and part are scattered in
all directions by irregular reflections; so that rarely more
than half is reflected, even from the most polished metals.
Q.   Why are GREEN GOOSEBERRIES, CURRANTS?
4c., HARD; and RIPE ones SOFT.
A. Because they contain an infinite
number of little cells, with thick walls;
these  become thinner from  day  to  day,
as the fruit ripens, until they break; when
the fruit becomes soft.
Q.   Why is PORTER much DARKEr, than ale or
beer?
A. Because the malt of which porter
is made is dried at a higher temperature
and slightly charred.
Small beer is a weak wort fermented, and contains 1I
per cent. of alcohol.
Ale is a stronger wort, and contains 7 per cent. of alcohoL
Porter contains 41 per cent. of alcohol.
Brown stout contains 6} per cent. of alcohol.
Burtn& ale contains 8J per cent. of alcohol.




444          WVINE-H.AMS  ETC.
Q.  If w\INE or BEEr be, imperfectly corked, why
does it rapidly turn sour?
A.  Because air gets into the liquor;
and the oxygen of the air, combining
with the alcohol of the liquor, produces
ace'tic acid.
1 alcohol and 4 oxygen, become 1 hydrous acetic acid
and 2 water.
Q.   IT/zy does pyroligneous acid  PRESEiVE
MEAT and remove its taint?
(Pyroligneous acid, is vinegar extracted frtm wood.)
A.  Because it contains a small quantity of creasote, which is a great preservative of all animal substances.
Creasote, pronomnce Cre-a-sote (from two Greek words,
rpcas, flesh, and axcdJ, I save), an extract from the oil of tar,
and a powerful antiseptic.
Q.  lWhy are EHAMS preserved by  SMOKING
them?
A.  Because the smn-oke of a wood fire
contains creasote, which is a great preservative of all animal substances.
Q.  Is TrEA a NUTRIT[OJS beverage?
A.  Yes;  the  tea-leaf  contains  the
largest amount of nutritive matter of any
plant used as human food; thougrh only
a portion is extracted  by our common
method of making  tea.  When soda  is
added, the casein of the leaves is dissolved,
and thenutritive quality of the tea is
much increased.




SOAP, ETC.                  445
Casein pronounce Cas'-e-in, from the Latin word caseus,
cheese; lecause cheese consists chiefly of the casein of
milk. It is ibund in many vegetable substances, as peas,
beans, lentils, &c., and is the same as the substance called
legu'mine.
Q.  tHow  do the  Tartar tribes make a most
nutritious food from tea?
A. They boil the leaves with soda,
and eat them  with salt and butter.
Q.   SoAr is made of oil or fat.  lHow  is it
t.hat oil and fit make water greasy, whereas SOAP
destroys grease?
A. Oil contains two parts; the solid
part called stearine, and the liquid part
called oleine.
Stearine of oil is not soluble in water;
but when  soda  or potash is boiled with
it, the oily principle flies off, and the
stearine is converted into an oxide of
potassium, which is quite soluble in water.
Stearine (pronounce Ste'-a-rine), from the Greek word
Treap, suet; the acid of stoearine unites with the soda or
potash, and the oily principle called glycerine flies off.
Oxide of' potassium is the fundamental part of potash; it
is what chemists call a metallic oxide.
Q.   TVhat is the difference in composition between
HARD soap and SOFT SOAP?
A. The hard soaps are made of soda,
and the soft soaps are made of potash.
Q.   WThy is sorrel sour?
A. Because it contains oxalic acid.
Oxalic, from the Greek word o4a~e, sorrel. Oxalic acid
W sometimes erroneously called " salt of lmowns."




446          APPLES-VINEGAR.
Q.   Why are unripe APPLES, GOOSEBERRIESi
and RIIUBARI1, SOUR.
A. Because they contain malic acid.
Ma'lic, from the Latin word malum, an appic.
Q.   Why are tamarinds and unripe GRAPES
sour?
A. Because they contain tartaric
acid.
Tartaric acid is the acid of tartar. Tartar is a substance
deposited by wine; adhering, like a hard crust, to the
sides of the casks.
Q.   Why does TANNING hides convert them into
LEATHEr?
A.  Because oak bark contains tannic
acid; and, on evaporation, this acid precipitates  a  solution  of glue  upon  the
hides, which converts them into leather.
Q.  WThy are citrons, limes, LEMONS, and unripe
ORANGES, SOUR?
A. Because they contain citric acid.
Citric, from the Latin word citrus, a lemon or citron.
Q. Why is VINEGAR SOUR? 
A. Because it contains ace'tic acid.
Ace'tic, from the Saxon word aeced, vinegar; whence
also acid, i. e. like vinegar.
Q.   Why do old WIN} CASKS SMELL OFFENSIVELY?
A.  Because wine (ald whiskey) ccntain an acid called cenanthic acid; which
unites with the alcohol cf the wine, and
forms a salt of an offensk;e smell.




CANDLES-TEETH.                   447
This salt is called the cenanthate of ethyle, i. e. the
wiLey acid of ether.
CEnanthate, from  the Greek word otvo;, wine; and
" ethyle," fiom the two Greek words, atnOp-vn, the basis:r fundamental principle of other.
Q.'When a CANDLE is BLOWN OUT. whence
arises the OFFENSIVE ODOR?
A.   The tallow  distills a substance in
the smoke, called acryle, which has a
very offensive smell.
"Acryle "(pronounce ac-ryle) fiom two Greek words,
aKpin-v2A, the basis or principle of a wick or end, i. e. the
odor which issues from a wick-end, after it has been
blown out.
Q.   TWhat causes the decay of teeth?
A.   After the enamel is worn  off, the
dentine or ivory of the tooth is left bare:
This dentine or ivory is full of little tubes,
filled with lime; Now, the acids of saliva,
mucus, and food, dissolve. this  lime, and
fill the tubes with foreign matters; after
which,  the  tubes  dissolve  or  crumble
away, leave the nerve exposed, and the
pain of tooth-ache ensues.
Dentine (from the Latin word dens, a tooth) is the main
part of the tooth.
Q,   Why does CREASOTE CURE TOOTH-ACIIE.
A.   Creasote  acts  as  a  caustic, and
burns away the mortified bone, or ulcer
formed upon it, which produced the
pain.
Tooth-ache arises from numerous causes, as cold,
stomach, caries, or decay, &c. C(rcasote is a remedy fol
tooth-ache only when the pain arises from caries.




448         INDIAN RUBBER, ETC.
Ca -ri-cs is a Latin word which signifies, mortification or
2lcer of the bone.
Q.   What is Indian rubber?
A.  The  oil or resin  fiom   various
species of ficus, oxidised in contact with
air.
" Fi'-cus," the fig-tribe.
Q.   What is gulta percha?
A.  The oil or resin of a tree which
grows in Malacca (Asia), called Isonandra gutta, oxidised in contact with air.
Q.   What wines contain the MOST spirit, and
what the least?
A.  GCanmpagne is one of the weakest
wines, then hoclc, then claret, then sherry,
and pIort is one of the most potent.
Four glasses of port being nearly equal
to five glasses of sherry.
Champagne contains about 12 per cent. of alcohol.
IHock       "   "    13      "       "
Claret      "   "    16      "        "
Slherry     "   "    19      "       "
Port        "   "    23 t "           "
Q.  lWhat is the origin of the term  PRooF
spirit?
A.  It is derived from  the old method
of testing spirit, which  was thus:  the
spirit to be tested was poured over gun.
powder, and ignited; if the powder exploded, the spirit was said  to  be above
proof; if it did not explode, it was said
to be below proof.




STEEL-MARKING INK.           419
Q. What do we mean, at the present day, by
spirit above and below PROOF?
A. If we say that spirit is 10 over
proof, we mean this —-that 1.00 gallons of
it will require 10 gallons of woater to reduce the spirit to proof strength. So on
the converse, if we say that spirit is 10
under proof, we mean that 10 gallons of
water must be taken friom the spirit to
raise it to proof strength.
Proof spirit has.91833 specific gravity; the strength of
spirit is now tested by an instrument called an hydrolm'eter.
Q. How is STEEL made from IRON?
A.  The iron is surrounded with charcoal, and placed for six or eight days in a
furnace, intensely heated; the  carbon
unites with the iron, and forms what is
called " carburet of iron" (or steel).
Q.  What is meant by " SHEAR STEEL?"
A.  Steel used for making  shears, for
dressing woollen cloth: Shear steel is
broken and welded frequently.
Welded, i. e. hammered together again.
Q.  What is common MARKING INK?
A.  There are generally tiwo bottlesone containing a solution of the carbonate of soda: and another containing a
solution of nitrate of silver.  The cloth
is first moistened with the carbonate of
soda, dried, and then written on with a




450.JEWVELLER'S GOLD,  ETC.
pel dipped in the nitrate of silver.  An
oxide of silver is thus precipitated, and
leaves a black mark behind.
Q.  What is JEWELLER'S GOLD?
A. An alloy of gold and copper with
silver-this gold is liable to tarnish, but
its brilliancy can easily be restored, by
immersing the metal in ammonia.
Q.  I-low is IRON GALVANIZED?
A.  By plunging  it into melted zinc;
when an alloy is formed on the surface,
which prevents oxidation.
Q.  What is the diference between LEAD and
SOLDER?
A.  Solder is a mixture of lead and
tin.
Fine solder is 2 tin and I lead.
Coarse solder is 1 tin and 4 lead.
Q.  MT;hat is TWHIIITE LEAD, used foi paint?
A.  It is prepared by placing sheets
of lead over earthen pots, which contain
weak acetic acid, atnd sttlnd uponi tan or
dung. The lead, being corroded with
the  acid, unites with the carbon  and
oxygen evolved from the dung.
Q.  Wthat is rEWTER?
A.  An alloy of lead (or bismuth) and
tin.
In the following proportions: 1 part lead and 20 parts
tin.




TIN-FIREWORKS.                   451
Q.    Wat is BLOCK TIN?
A.   Tin purified by heat, and  run into
nloulds,  which   forLn   blocks  of  great
size.
Some 3 cwt., and some even more.
Q.  1How  is the GREEN FIRE of fireworks pro.
duced?
A.   By the  nitrate of bary'tes, which
burns with a green hue.
(Barytes, pronomnce ba-ry'-tes) an earthl so called from a
Greek word which signifies heavy, (0apvr.) It is made
thus; 100 parts of nitrate of bary tes well dried,- 9 of sul —
phur, 7 of clllorate of potash, 2 charcoal, 4 sulphuret of
antimony, all well dried and mixed in a mortar:
Q.   HIow  is the RED  FIRE of fireworks produced?
A.   By the nitrate of stron'tian, wlhich
burns with a red hue.
(Stron'tian is an earth, so called from a village in
Argyleshiire of the same name, where it was first discovered.) It is made thus; 100 parts of (dry nitrate of
stron'tian, mixed with 12 parts of chlorate of potash, 30
sulphur, 10 sulphulret of antimony, and 3 charcoal Ka
dried and rubbced curejttlly in a mortar.
N. E. —Unless care be taken the mixture will explode.




L52                POISONS.
ANTIDOTES FOR POISONS.
Q.  Of a  person has swallowed a MINERAL,
poison, such as ARSENJIC what is the best antidote?
A.  A tca-spoo)ful of sul/phltr-or half
a tea-spoonful of pearl-ash —or a twineglass of soap)-suds:
After a little while, give a table-spoon.ful of antimonial wine, and  plenty  of
walrm  water.
Q.  if ac person has swallowed a VEGETABLF
poison, such as SULPHURIC ACID, AQUA-FORTIS or0
OXALIC ACID7 what is the best antidote?
A.  Lime, chalk, pearl-ash, magnesia,
carbonate of soda, or soap-suds, and  a
plenty of warlm water; a dessert-spoonful
of antimonial wine should be added, if
at hand.
The chalk or lime, &c., unites with the oxalic acid, and
forms oxalate of lime, which is quite innocuous.
Q.  If LAUDANUMI has been taken, what is the
best antidote?
A.  A  tea-spoonful of common mustard; and to keep the patient walking.
Q.  If CHLORINE has been taken, what is the
best antidote?
A. Ammonia, which will neutralize
the ill effects of chlorine.
Q.  If IODINE has been taken in too large a
quantity, what is the best antidote?




ANTIDOTES FOR POISON.           453
A.  Iron-filinags are the best antidote
for an over-d(ose of iodine.
Q.  If a person. feels faint from the fumes of
PRUSSIC ACID, what is the best antidote?
A.  To smell the vapors of strong ammonia, which  will soon  restore  consciousness.
Q.  Il(ow can WARTS, 4'c., be RElMOVED 2
A.  By rubbing  them  with  common
solid potash.
Q.  TWhat is the best antidote to vErDIGRIS?
A.  Sugar, or white of e,,.
Q.   wtIhat is the best antidote to coRnosivE
SUBLIMATE?
A.  White of egg, or milk; which will
combine with them, and neutralize their
poisonous qualities.
Q.  if a person has eaten too vnuch FRUIT, what
is the best anitiole?
A.  Lime, chalk, pearl-ash, magnesia,
carbonate of soda, or soap-suds.
Great relief is often found by eating the hard part of
cheese (cut close to the rind) thickly covered with common sal;; the reason is plain.




GLOSSARY.
Acetic  Acid.    called    Distilled Vinegar.
Citrlc    "        "       Juice of Lemons.
Nitric    "        "       Aqua Folrtis.
O.canlic   "       "       Salt of Lemons.
SIdI/lu'riC   "    "       Oil c-f Vitriol.
SiLdplt. of Allmina  "     Alum.
(9    Lime       "       Plaster of Paris.
"     Iron       "       Green Copperas.
"      Copper    "       Blue Vitriol.'  Mnagnesia "   F)soml Salts.
"      SSoda     "       Glanber Salts.' Zinc          "       Whlite Vitriol.
Nitrate of Potash   "      Saltpetrc.
"     Silver    "      Lunar Caustic.
Prussiate of Potash "      Prussian Blue.
Tar/lrale of Polash  "     Rochelle Salt.
Acetate of Copper   "      Verdigris.
M:tria/le of Soda    "     Table Salt.
Oc.ide of Lead     "       Goulard.
Carb. of Ammonia  "        Smelling Salts.
"     Lime       "       Chalk, Marble, &c.
Sap. Acetate of Lead"      Sugar of Lead.
SUIBLIMAT'M:S are chemical preparations, the basis of
which is quicksilver.  In CORROSIVe: SUBLIMATES, the
quicksilver is extinbguished either by vitriol, potter's clay,
or some other ingredient.
SUEr.LIMATIoN is a similar process to distillation; only
solids (such as metals) are employed, instead of liquids.
Thus the fine blue used by painters is a sublimate, and
made tllus:-Take 2 parts of quicksilver, 3 t\ower of' brimstone, 8 sal aninmoniac; and (having ground them) put
them with the quicksilver into a glass reto(rt, luted at the
bottom: place the retort in a sand-heat; and (when the
moisture is given off) you will have a splendid blue sublimate for painting.
N. B. It may be profitable to remind the pupil that
when the termination "ous" is used, it imnllies that the
substance has less oxygen than when thle tet'rmillnation " it;'"
Is added —-thus, sulphurous acid contains less oxygen than
sulphuric acid, &c




INDEX,
Fige                        Pax
ABSORBERs,...... 173  Air dries linen.. 1. 1
not conductors 173    elements of....... 219
not reflectors.  179    expanded by heat 102, 268
radiators..... 182    full of smells...... 143
ABSORPTION Of Hn:A'T.. 173    gets fire up........  54
not conduction 178    healthful.......... 242
of light....... 339    heated.... 202, 220, 270
ACCIDENTAL COLORS.. 375        not by thesun 181, 226
Acetate of copper.... 451    hotter when the sun
Acetic acid.........  464      shines........... 227
Acid of drinks........  248    in a room.........  270
of fermentation.. 248    inflammable, see hyAcids dissolve ice....  32     drogen.
Activity  affected  by        needful for fire.....   63
cold........ 90    non-conductor......  19
"  by heat...... 92    of cities unhealthy
Aerated water:........ 247                    223, 242
Aeronauts feel pain 138, 229    of the country healAge affects power of            thy......... 223, 242
walking............ 392    on land colder than
Aged people far-sighted         on water........ 207
361, 363    on land cold at night 211
I.R               219, 268    preserved normal... 224
always in motion.. 270    purified by lightning  32
ascends when hot.. 268    radiates no heat.... 202
bad conductor 15, 165,217    rarefied is noiseless. 139
bad radiator....... 202    rarefied, bad conduccold...........    166              tor of sound. 383
colder than blood.. 169      "    bya crowd.. 239
composed  of two            rusts iron.......... 231
gases........ 30, 219    still before a tempest 139
condensed by cold.. 269    use of oxygen in.... 220
cooled by convection 202    varies  in  temperacooled by rain...... 150     ture............ 313
cools hot iron...... 227  Air-gun............. 101
density diminished by     Air-pump freezes water 335
rain............  315  Aisles famous forechoes 384
descends when cold 269    colder than galleries 229
double current in a       Alcohol............. 249
room............ 270    from  sugar....... 260
(For Index to Part III, see page 486.&




456                     INDEX.
Page                         Paw
Alcohol, boiling point of 115  Balloons............. 138
ALE..........  107         inflate..........   107
bottled............ 248       rise (sec acroaults.) 107
froth of............ 248  Balls of fire..........  14
"increased by heat        Balusters wet........ 200
107, 218  Banisters, see b&adIsters.
Alkali............     50  Barley naltetl........   251
Ammonia............ 254  BARO.I+:'rT:,.......... 296
Anemometer........    294       affected by cold.. 300
Anglers hate a magpie 145              i    frost.. 299
Angle of incidence.... 344             "    heat.. 302
of reflection.... 344           "     thaw.. 300
Anhydrous sugar...... 250             "    wind.. 299
Animal fluids conduc-             rules for its rise
tors.                20          and fall.. 299, 308
ANIMAL HEAT...  83, 258          sudden chaung e in 302
caused )y com-             use of'........  298
bustion.....   85       varies most in winAnimal and vegetable                tcr............ 306
life dependent...... 225       "least in summiier 306
Animals for bode rain.. 141        when lightle.st... 306
Ants love honey-dew.. 204           l" oecst... 307
Appetite, see hunwger.       Barren land collects no
Apples full of air.....  104    dew............... 194
roasted....... 103  Bass notes in ilmlsic..   379
soft.......... 104  Bass preserves flowers
April showers........ 288    from frost..........  191
Aqua-fortis.......... 454  Bathing, danger of.... 359
Argand lamps........  82    "  with ctlher for inAscent in balloons pain-          flainialtiol..... 148
ful................ 138  Beakers broken by hot
Ashes soften water.... 322    water.120
Asses bray in wet wea-       Beasts covered with hair 165
tlher.............. 141  Beds danpl..........    149
Atmosphere (see air).. 284  BEEn, ferlllentation of 249
Aurora borealis...... 1,36      flat............. 255
colored.......  136     froth increased by
white........ 136          bottli,, g........ 248
a prognostic.. 136       froth increased by
Autumn tints........ 372          heat...... 107, 248'
Avenues............ 353         stale............ 255
Azote, see Litrogeen.            souredl by lightning  32
not old( ber....  32
Bales catch fire spon-           spoiled. if the venttaneously.........  60          peg be left out 255




INDIEX.                     457
Page.                         Page
Beer, yeast added to         Blocd, red.......222, 223
make it work...... 251  Blowers.............  70
(see vent peg.)        Blowing cools broth, tea,
Beer-vats dangerous.. 245    &c..        168, 293
Bells heard at a distance 380  Blue.                 454
cracked, sound harsh 378        sky............. 126
ringing dangerous..  23        spectacles........ 375
silenced by a touch 378         sublimate..... 454
Bell-metal.......... 378  Body, fuel of........  86
Bellows..............  55          warm...... 84, 258
Bible explained.. 161, 195  Boiler, see saucepan.
311  BoILING............. 213
Birds covered with fea-         "  WATER bubbles.. 111
thers.              165           furr of........ 236
Bins purified by lime 259            makes it flat.. 257
BLACK.............. 371             is in a ferment 214
cloth warm......  174            kept hot...... 187
eyes............ 179             rattles........ 112
glass for spectacles 376         runs over..... 111
hat turns red at the             swells.        110
sea-side........ 321       one pot will not boil
hole of Calcutta.. 240         in another..... 113
Black kid gloves...... 176       retarded by a spoon 113
lead............. 232 " by salt, sugar 114
prevents rust.. 232       without touching
mist............. 137          the boiler...... 114
skin........       178  Boiling point........ 115
tea-pot.......... 184  Boots hot when dusty 181
used by cotters 184  Bottled ale, &c....... 248
set on a hob to        Brackish water unfit for
draw........ 184    railway engines.... 237
will never blister.. 178  Bracing weather...... 140
Blacksmiths strike fire      Bread heavy......'... 258
by nails......       95          made with yeast 257
Bladders inflated  by        Breath exhaled...... 223
heat... 102, 269         inhaled........ 221
BLAZE, blue..........  50          visible in winter 200
green..........  50  Breathing described.. 224
yellow.........  50       difficult on a mounbetween the bars             tain........... 229
of a grate....  50       previous to a storm 229
Blazing  coals burn          BREEZE  at watering
quickly...........  44             places....... 291
Blood......... 222, 238           evenipg........  290
purple......  222             land.. 291
20




458                    INDEX.
Page                         Pap
Breeze, morning...... 289  Candle-flame purple beof islands...... 291             low........   76
ea........ 290, 291           tends upwards 77
speed of....... 293           yellow.......    75
(scc win'd.)        Candles, gas of.... 84, 262
Bricks for cold feet... 162     held at a door 270, 271
Brick stoves......... 163       hottest above the
Bricklayers cannot work             flame..........  78
in a fiost.... 334      give light.......   75
cover worlk with           make glass damp  78
straw........    334    need snuffing....  80
Bright day exhilarating 137      Palmer's.........  80
Brilliancy............ 339      prevent our seeing
Brine retards boiling.. 114         abroad...       352
tested..        335       reflected in a winBritain cloudy........ 123         dow........... 352
Broth cooled by breath 2 27      rekindle quickly..  55
by convection 228       rush, easily go out 78
by stirring.. 228      shadow cast by.. 3852
Bubbles in tea........ 387      smoke of........  81
of boiling water 111      spirt............ 146
Bulk for bulk........ 107       suddenly introduced
Burns cured.......... 148          give p)ain...... 339
Bulnt stick twisted.. 374       wax, need no snufBurning glasses......  10         fing...........  80
Candlestick rags catch
Calcutta, black hole of 240    fire spontaneously..  61
Calcareous........... 225  Cannon balls hot.        101
Caloric...........    9            boring......   100
Cambric handkerchiefs        Canvass flower-awning 191
cool............ 172  Capillary attraction 75, 172
Camphor antiseptic... 389                            388
CANDLES.............    74            vessels......  83
burn...........  74  Captain Ross......... 381
cotton, not easily      Capuchin............ 317
blown out.....  78  Carbon............  40, 74
easily blown out 55, 77        in the blood.... 238
extingIiished.....  79  Carbonate of ammonia 454
bya pin.......  81               of lime.... 454
breath.....   77  CnRBoNIC ACID GAS 43, 238
paper.....   79       absorbed by leaves 225
flame blown out..  55       accumulation of,
hot.........  76          prevented...... 246
hollow......  76        deleterious......   238
pointed......  77       detected.........  239




INDEX.                     459
Page                         Page
Carbonic acid gas dis-       CHEMICAL ACTION.....   36
sipatedby red heat 216  Chestnuts crack when
in hulnan bodics..  84            roasted...... 102
of the soil........ 225       not if slit...... 103
sources of...... 245  Chimney pots........  70
CARBURETTED HYDROGEN                  flueos long....  64
GAS.         263               sho  t       64
GAS............... s26              "short......  64
Carpenters' tools hot..  99           raised above a
Carpets warm......., 157              house... 64, 68
Cavriage in a storm..  26  CHIMNEYS SMOKii.....  63
wheels catch fire  98        if a room be too
windows misty. 197             close........  63
Casks charred........   72         remedy.......   64
Cart-grease..........   98        in old farm houses 69
Cathedral aisles famous             valleys........  67
for echoes......... 384         in wind.... 70, 108
CATrs in wet weather.. 140         if too-long.. 64, 108
prowl by night    342  Chimneys smoke if too
rub their ears....  142       short........  64
see in the dark... 311           remedy......  66
wink before a fire 342         large              69
Cattle low in wet wea-                remedy......  70
ther......... 140       when the draught
in a storm..... 25          is slack..... 65, 69
Caustic lime......... 390        when the door is on
lunar.             454         the same side..  68
Caverns famed for ech-                remedy......  68
oes............... 383    when they need reCeilings sooty........  71           pairing......  69
Cella'rs cold in summer 231         sweeping......  69
warm  in winter 231        when two fires are
Cerebellum........ 391            in one room....  67
Cerebrum............ 391             remedy......  67
Chalk.............. 454  China broken by hot
Champagne acid...... 248    water.............. 120
CHARCOAI.............  72  Chlorophyll.. 3....7. 372
bad conductor.... 156  Choke damp.... 244, 261
fire very hot.....  72  Church bells heard at a
" deleterious.    245             distance  139, 380
purifies water....  72      congregation drowsy 241
removes taint....  72  Churcllhyards smell offenCharring bread....... 73    sively............. 265
casks..........  72  Chyle............... 221
wood........ 73  Chyme.............. 221




160                     INDEX.
Page                         Pa
Cinders, iron........  48  Clouds, distance from
lighter than coals  48         the earth...... 123
soon heated......  48       edges most lumiwill not blaze....  52         nous.......... 36,
C(irro-cumulus clouds 130        electrical....... 12,t
Cirro-stratus clouds... 130      fall in rainy weaCirrus clouds........ 128          ther........... 315
Citizens pale......... 222       fantastic........ 131
Citric acid........... 454      float............. 123
City air unhealthy.... 242     gather round hills 132
Clay for furnaces....  163       height of.      12, 124
Clean kettles......... 174      highest.......... 124
Cleanliness connected            highest in a fine day 115
with the dietary  93       increased by wind 166
poverty..........  93       intermediate.....  130
Clear day overcast.... 285       light............ 115
fire buins slowly.. 44      lowest........... 124
nights  exkilarat-           morning  red...... 127
ing............ 137        motion of........ 127
Clocks heard at a dis-           nimbus......       131
tance.............. 380        thin indicated by. 131
Close rooms unhealthy 240        red......... 126, 369
Cloth collects but little        round  mountaindew..............   143         tops..........  132
Clothes gather damp in           simple....    128
summer..... 195           size of..........  124
wet............. 148        stratus.........  129
Clothing for workmen 154         sun-set...    133
loose warmest.... 165      thickness of...... 124
promotes warmth 164            how ascertained 124
want of makes dirt           thunder.........  15
agreeable......  93        vary in shape.... 124
Cloudiest countries... 123        in color........ 127
COUDS..............   122    where most abundabsorbed by wind 125           ant............  123
cause of......... 122       where least...... 123
cirro-cumulus.... 130       use of........... 132
cirro-stratus..... 130      velocitv of....... 294
classes of........ 128      wind affects them
color of..... 124, 126                     123. 1'25
coml)ound....... 130        yellow...... 133, 134
cumulo-stratus... 131        indicate wet..... 134
cumulus....       129  Cloudy night warm... 189
differ from fog 122, 209         oppressive      137
dissipated... 125, 133  Coal gas.......... 74, 262(




INDEX.                    461
Page                        Pag
Coal mineu explode.,. 262  CoMrlrFsso........ 1
Coals black.371                differs from  conblazing..........  44        densation....   (9
grotesque figures of 46  CONDENSATION.......    99
for fuel..........  48  Condensed air........ 269
smoke.........  45  CONDUCTION.........  55
Coffee,   spontaneous             not absorption.. 173
combustion of....  61
aCokte.5........... ~.. 69  CONDUCTORS, best....  56
for fuel..........    48      orst.....5
spontaneous corm-             animal fluids...  20
bustion of.....   G0 not absorbers.. 173
COLD WEATHi:,R affects            of lightning....  27
the   barometer             dangerous.....  29
299,306  CoNvEcTIoN.....   202, 213
makes us love fat 89  Convective currents 226,270
activity......  90        cool broth.     228
out of doors...... 293           iron....... 227
promotes hunger.  90  Cooking  vessels with
Colder some things than       wooden handles.... 156
others.........: 155  Cooper  applies  hot
Colds from wet clothes 149    hoops...    117
Collapsing....... 104, 269  Copper for conductors  28
Color of clouds....... 123      sonorous...... 378
electricity...  35       tarnishes..... 233
Colors............... 364  Cork driven out by heat 106
accidental..... 375  Cornea.............. 360
dark, warm.... 175  Corns ache in wet wealight, cold..   175    ther............... 230
vary.......... 370  Corpse cold..........  94
Combining not mixing  31  Corrosive sublimates.. 396
COMBUSrION (see Jie)..  83  Cotton bales catch fire  60
animnal..........   8          spontaneously. 60
cause of.........  43        candles hard to
chemistry of... 40, 43          blo v out....  78
from fermentation  60       handkerchiefs hot 172
elemnents of......  43     oiled transparent. 373
heat of..........  40  Countries nmost cloudy 123
increased by wind  55             least cloudy 123
in the veins......  81  Country air salubrious
produces light....  51                   223, 242
spontaneous... 60, 81  Countrymen       enjoygCOMMUNICATION OF HEAT         health............. 242
155             ruddy..... 221
Compound clouds.... 130  Cowls............ 67, 108




462                     IINDEX.
Page                         Page
Crowds dangerous in a        Dark colors warm.... 176
storin........   24           radiate hcat.. 183
produce drowsiness 242  Davy, Sir H...... 263
head-ache. 239  Day - light  pl)oduces
vitiate air........ 239            hunger....    88
unhealthy.....  240              mitigates cold  88
Crucibles made of pla-       Dead bodies cold.        94
tinum............. 236           smell.......... 2C6
Culinary vessels...... 186        taller than living 390
have wooden handles 156  Deafness............ 382
should be sooty.... 186  Decanting liquor.....  256
Cultivation   promotes                    spirting.. 266
dew............... 194  Decomposition....... 246
warmth... 152  Deep  water  fieezes
Cumulo-stratus clouds 131    slowly............. 331
Cumulus clouds...... 129  Depression of spirits.. 137
Cup in a pie.........   116  Descent in a diving bell
use of......... 117    painful.......... 138
why filll ofjuiee 117  Deserts hot and dazzling 374
Currents of air....... 270  Detonating powder... 101
DEw................ 188
Damp balusters...... 200        cause of......... 209
beds.......... 149        deleterious...... 203
clothes........ 195       differs firom rain.. 209
house......... 200      distilled after a hot
Dandelion   forebodes              day.......... 202
rain............ 142        especially  if the
DArGER IN A STORM...  18           wind be westerly 202
in attics and cellars  22    in fine nights only  189
a crowd.......  25        distilled unequally 192
in a theatre,&c...  25       in open places.... 190
before a fire....    25    in valleys and hollows 191
near a tree......  19       on clothes........ 195
in a river......    19       cultivated lands.. 194
flocks and herds are         grass............ 194
exposed to.....  25       hair............. 201
those   who   bar            hat.............  201
shutters...  24        leaves, &c........ 1.93
those  who  drive          none beneath a tree. 190
fast........... 21           a flower awning  191
lean against a              a hedge or wall 191
wall..... 23    none in a cloudy night 189
or carriage.  26         in a windy night 191
who ring bells 19, 23         especially   if
run.        21             easterly.... 201




INDEX.                    463
Page                        Page
Dew, none on stones, 191  Dry wood burnsbest.. 106
t.oth, deserts,grav-            snaps about.. 106
el, metal, rocks,     Driest months........ 307
wool........ 194  Dublin, rain of...... 317
Dew-drops round..... 205  Duck dry in water.... 206
flattened.......  205       noisy before rain 141
r6ll on cabbages 205  Dullness......... 339, 371
"   roses... 206  Dunghills hot....... 258
Digestion............  90  Dusty shoes hot...... 181
Dinner covers........ 187
Dirt warm...........   93  Ear trumpets........ 382
Distant bells heard.... 380  EARTHI, bad conductor. 170
clocks............ 381      cool in sumnmer... 170
objects appear small 354     cools after sun-set 189
sight.        361, 363          in a fine night 189
spectacles for 362      cracks by frost... 332
Distance makes things           crumbles in spring 333
invisible....      357       warm in winter... 170
Distilled vinegar..... 454     warmer than  air
Divers suffer pain  138, 230      by day....... 189
Diving bell.......... 138  Earth-fog.......... 204
Doors swell and shrink 143  Earthen tea-pots.     184
Dogs  uneasy in  vet          set on a hob to draw 184
weather.......... 140  Eat more in cold weaDough fermented..... 257         ther...........   90
set before a fire to rise 258  less in warm weaDouble concave glasses 361        ther...........  90
convex glasses....  362  Echo................ 383
Down warm.......... 165  Echoes, two or more.. 385
Draining lands promote              remarkable.. 385
warmth...........   151  EFFECTS OF HEAT.....  101
DRAUGHT at a door.... 294  EFFERVESCENCE......   247
key-hole. 294           soon subsides 257
window.. 294  Effervescing draughts. 247
slack....'.. 65, 23  Egg, component parts of 254
Dreams.......    390    discolors silver spoons 254
Driving  in  a  storm         new-laid, cold...... 167
dangerous.           21    stale, warm...    167
Drops of rain r6ll on          " smells offensively 254
dust.............. 206    tests brine...    335
Drowned men restored  99    tested.......       167
Drowsiness at church.. 242  Egypt not cloudy..... 123
Drums.............. 379  ELECTRICITY affects the
Dry toast for invalids.  73       clouds.... 125, 127
wood for kindling  49       excited by friction  34




464                     INDEX.
Page                         Pao
Electricity felt at the      Eyes affected by sudelbow joints....  34         den light...... 339
hot.............  34        affected by the sun 375
odor of..........  35       black............  179
of clouds..... 11, 127      cornea of........ 360
positive and nega-           retina of.....    360
tive........... 22   two, use of.......  343
resinous and vitre-            "  see single.... 343
ous... 11, 23
source of heat....  11  Face soon scorched... 182
Electric telegraph....  36  Fanlling........ 167, 293
Elements of air.......  40  Far sight........  361, t)3
of fuel......  40         spectacles for.. 362
Emetic tartar........ 451  Farm-houses smoke..  69
Epsom salts.......... 454  Fat nmen swim best... 337
Esquimauxloveblubber 91  Fat pleasant in winter  89
Equatorial current.... 0278           not in summer  91
ETHER..............  51   Feathers warni....... 165
boiling point of.. 115  Feeling............... 392
used for freezing.. 335  Feet cold before a fire.  57
inflammation,           wet dangerous    148
scalds, burns. 148  FERMENTATION.......    249
vaporized........  148         differs from  puEuropean skin white.. 178             trefaction.... 252
EVAPORATION........ 147            of dough...... 257
freezes.... 335          produces  comof sea.      276           bustion......  60
EVENING CLOUDS.. 126, 133          requires water.. 155
grey...... 135  Fender and  fire-irons
red 126, 133, 370    cold...............  173
yellow. 133, 234  Fiddle-strings musical 378
Evergreens frost-bitten 212           sila)p from wet 316
Ewers broken by frost. 325  Fine weather braces.. 140
EXPANSION by HEAT 101, 117             indications of 134
Explosion  of roasted        Finger feels cold whllen
chestnuts.... 102     wet.                  148
of gunpowder.. 103  FIRE................  39
of mines....... 263       air necedfill for....  63
Extinguishers........  79        bellows, use of...  55
made of paper  C9        black and red....  44
Eyes adapt themselves            blazes........    44
to light........ 310        not in frost....  52
affected  by  blue           burns blue....... 141
glasses........ 375       cause of.........  43
affected by fire-light 374    charcoal......... 




INDEX.                      465
Fire, charcial danger- Pag   Fishes ascend and dive 1 3a
cus......       2-15       seem nearer than
clea-........44,.53         they are...... 359
damp.......... 261           cold............  93
differs from animal      FLAME of a CANDLE...  75
heat..........  85        described........  76
dull, cause of....  65     bllown out easily..  77
effect  upon  the            damp...........  78
eyes...... 41, 374        hollow..........  76
extinguished....  57       hot............   75
by water 57, 106       hottest above....  78
fiercest in winter. 53      luminous........  75
out of doors..  54       pointed..........  77
gas generated by  84         pl':ple and yellow   76
grotesque  figures           smokes..........  81
in............  46  Flame of a fire between
heat of.......... 258         the bars of a grate 50
how increased 53, 63       blue............  50
hot.............  44         green...........   50
kindled at the bot-      Flame yellow........  60
tom...........  47  Flannel warm........  93
lighted with paper           used for foot-warmand wood......  46          ers............   93
light dazzles...   340  Flash, see l1itohlning.
-lght variable....  52  Flat beer, &c......... 255
luminous........ 50          iron............ 147
melts metal...... 121  Flavor discerned by the
mottled........  45    taste.............  392
out of doors.....  45  Flax  burns spontanepoker draws up..  56    ously..............  60
ra(liates heat..... 182  Flint and steel strike
red hot......44, 330    fire...............  96
reflected  on win-       Flocks  dangerous  in
dows.......... 352    storms............  25
spotted..........  45  FLOWING WATER freezes
sun dulls it.......  53       slowly.........  329
thaw dulls it.....  55       makes rough ice.. 330
wind intenses it..  55      oscillates........ 824
S&e combustion.            pure............ 324
Fire irons cold....161, 174  Flower awnings arrest
hot......... 174              dew......... 190
rust........... 231         purify air......'232
"  most in win-      Flowers smell sweetest
ter......  2:2       at  night, and
prevented. 232          befjre rain..... 14,20l




466                     INDEX.
Page                          t
Flowers forebode rain 142  Friction excites electriFlues...............  64           city..........34
blacked......... 183        sets foresfs on fire  99
long,  good   for        Frogs cold........   94
draught.......  66        croak before rain 141
short, bad    "     65  FROST affects baromeSee chimney.                ter............ 299
Flutes............ 379                 "  sound.. 380
Fly poison........... 390         braces........... 140
Foam, white......... 371         breaks ewers..... 325
FOGS................ 208         "tiles, stones, rock 325
arrest sound..... 381        " pipes.......... 327
cause of......... 123       cracks earth.      332
differ from  cleod              "  mortar..... 333
122, 209      expands water.... 325
mist......... 209        on windows...... 220
dispersed by wind 210        prevents fog.... 209
dispersed by sun 209         stops work....... 334
frozen........... 212       warmer than thaw 332
in autumn......   209  Froth of beer.... 107, 248
increase distance. 141       of fermentation..  255
in marshes...... 208         white........... 372
in valleys........ 210  Frozen water warm.. 330
magnify......... 141        ruts and foot-prints 326
none in a frosty night 209  Fruits cool the blood..  92
Food converted to blood 221      fall to the earth.. 388
cooled  by  the             pleasant in summer 91
breath........ 293  Fuel, dry burns well..  49
Food, want of, produces           elements of......  40
hunger......  89        for the body.....   86
want of, produces w,         et burns badly..  49
laziness.....  89  Fulgurites......   35
aversion to clean-     Fumigation  for  sicke
liness.......  93       roJmms........... 389
"to ventilation  93  Fur:.el (see flues)....  64
Foot-prints frozen.... 325  FUR, bezd conductor.. 166
Foot warmers........ 162        for clothing...... 164
Forked lightning.....  12       warm.......... 165
Forests catch fire spon-     Frnaces of brick.... 163
taneously....  99           lined with clay 163
cold.......... 152  Furr of kettles...... 236
France warmer than of            steam-engines danyore.............. 153          gerous........   237
FREEZING MIXTURES... 335
FRICTION (see rubbiitg)  97  Gallery hot...... 229, 294




INDEX.                      467
Page                         Page
Bas...........  74, 109, 19  195, 225, 283, 289, 328, 333
differs from liquid 220  Gold never tarnishes.. 235
elastic.......    220  Goodness (sea wisdom).
invisible........ 219  Grape sugar..........  249
jet of............  79  Grape juice needs no
of candles........ 263        yeast.......... 254
Gauze wire of safety-            ferments......... 249
lamps... 26I           makes alcohol.... 250
prevents explosion 261          "  carbonic acid 250
Geese noisy before rain 141  Grapes never ferment. 254
German silver tarnishes 235  Grass promotes cold.. 152
tinder........ 100      collects dew...... 194
Germany warmer than          Grate (see stoves).
of yore...........  153  Gravel collects no dew 194
Germination......... 288  Gravity............. 387
Ghosts.............. 266  Gray morning, sign of a
Gideon's miracle..... 195         fine day........ 134
Ginger-pop.......... 248         evening, sign of wet 135
acid........ 248  GREASE liked  in cold
GLASSES  broken by hot              weather.......  89
water.......... 119       loathed in hot....  91
broken if set on a           prevents rust...,. 145
hob......... 120        used for wheels..  98
covered with mist 198  Green color.......... 372
"if brought from            wood does not burn 105
cellar........ 199        "does not snap
dulled  by  a hot                 when  burned 205
hand...... 198  Grottoes  famous  for
"by breath, &c. 199    echoes............ 383
mist of, soon sub-       Ground frost......... 209
sides.......... 193  Growth  promoted  by
See spectales.           moonlight..........  203
Glass a reflector.....  352  Guinea fowls squall besoon cools... 1I''j,'J3    fore rain........... 141
ground r.ot trar, -      Gulls fly to sea....... 145
parentc..........73to land...... 145
See loolkinggl. s.      Gunpowder explodes.. 103
Glauber salt3......1. 54  Gusty weather makes a
Gloves, black ]iJ..... 176    smoky house....   70
Lisle threcd...  176
Glow-worms giten bj          HAIL..............   312
night.............. 342       accompanied with
Gluten.........       251          thunder          813
ferments...... 252  Hail, cause of........  313
GOD's WISDOM 153, 166, 193        falls in summer.. 31.9




468                    INDEX.
Page                        Pap
Hair, bad conductor.. 156  HEAT, LATENT...... 38, 9.5
covered with dew 201        of candles.......  75
warm........ 165           dunghills...... 258
Halls famous for echoes 381        fire.258
Halo round the moon 136            ice............  38
Handles, wooden.....  156         human bodies 84, 258
metal.......  156        lime.......... 265
Hard work promotes              radiates.... -... 182
hunger....  87       reflection of......   179
water bad for wash-         sensation of..       9
ing........... 234       sources of.. 10 to 101
Hartshorn.......... 253  Heating rooms by stoves
Hat covered with dew 200                       103, 183
turned red at the               by steam.... 183
sea-side...... 320  Heavy bread......... 258
Hawks see near and far 363  Hemp, spontaneous comHay-stacks catch fire         bustion of.........  60
spontaneously......  61  Herds  dangerous  in
Haze round the sun... 136    storms............  25
"  the moon 136  Hedges increase watmth 152
affects sound..... 381  Hills larger in a fog... 141
Head aches in a crowd 239       seem more distant 141
itches in wet weather 142  HOAR FROsT......... 211
Hearth-rug warm.... 159        not found on trees 212
RHearth-stone cold.... 159        under shrubs, &c. 212
hot..... 160       of fiozen fog..... 212
HEAT...............   9        on clear nights only 211
absorbed........  37       "grass.......... 211
and light........  51      " tombstones.....    177
affects barometer. 302      very partial..... 211
"  sound.... 380  HONEY-DEw.......... 203
animal... 83, 223, 258  Honey-dew, ants fond of 204
applied to the bot-           effects of...... 203
tom of boilers.. 214       injures plants.. 203
communication of 155  Htoops used red-hot... 117
conduction of.... 155  Horizontal  sun  and
effects of... 10 to 101    moon.350
evolved..........  37  IIorses strike fire.....  97
"  by compres-              snuff up air.... 144
sion...... 100        uneasy  in  dull
expands air...... 102          weather.      141
expands water....     334  hot, cloudy night opfrom  beaten iron. 94    pressive.......... 137
increased by accu-      Hot water.......... i87
mulation......  60         melts sugar.... 323




INDEX.                     469
Page                         Page
Hot weather abates ac-       IRON affected by lighttivity........   92       ning..........  36
abates appetite.  91       cinders..........  48
produces love of           cold............. 159
fruit....  91      contains latent heat 95
"dislike   of            cooled by air.... 227
grease...  91          "    convection 227
Hottest place at church             "    radiation. 227
229, 296      good conductor... 173
Houses catch fire spon-     I    heated by blows..  94
taneously....  59       rust............. 231
gather damp... 200       "when most cornseem  more dis-                mon......... 231
tant in a fog 141        "prevented...... 232
smoke in valleys  67       " scales.........231
Hull of ships seen last 358       sonorous........ 378
Hunger.......  87 to 91        stoves........... 163
promoted by cold  90  Ironing box.......... 147
"day-light......  88  Islands equable in tem" rapid digestion. 90         perature....... 291
" singing,  speak-           subject to wind... 290
ing, work....  88        warm..........    291
See appetite.          Itching in wet weather 142
Hydrogen gas...... 40, 74
of fuel...... 220  Jack o'-lantern (see igInis fatunus)......... 266
ICF.................. 325  Java (see jugngles)..... 241
contains heat....  38  Jet of flame through
dissolved by acids 332    bars...............  50
friction  99  Judges vi. illustrated. 195
salt... 332  Juice of lemons...... 454
sun. 121  Jungles of Hindostan
grows thicker.... 329    fatal.............. 241
lighter than water 325
Ice-bergs famous for         K       KETTLE boils over.... 111
echoes........... 384  quickly if coverIGNIS pFArUUS.... 266, 267          ed with soot. 174
cause of....  266         slowly if clean... 174
Impure water purified  72             "   if new... 174
Indian mode of striking             bottom   should
fire...............  97            be sooty..... 185
Inflammable air.... 40, 74          cold when water
Insects in wet weather 145            boils........ 186
Insensible perspiration 197        furr of........ 2i6
fntermediate clouds... 130          holder....... 167




470                    INDEX.
Page                        PNM
Kettle-lid clean..    185  Leaves in a pond.....
hot....... 186       lightgreen in spring 372
Kettle not full after           pale in dark places 372
boiling..   111         promote cold.... 152
runs over....   111       yellow in autumn 372
through the spout 112  Lemons, juice of...... 454
sings........... 109          salt of....... 454
steam of........ 216  Lid of kettle bright... 185
top bright..     185               hot.....  186
Kid gloves......... 176              rattles... 112
Kilkarney, echo of.... 386  Light bread.......... 257
Kindling fires......... 46     colors cool...... 175
dry.........  49  LIGHT............ 5, 338
wet.........  48       absorbed........ 339
composed of var!Ladies fan.....  289          ous colors 361, 370
Lakes  which  never             divided by a prism 364
freeze............. 331      from a flint......  96
Lamps..............  74        compression..... 100
Argand........   82      of candles.......  76
smoke.........   82        fire........ 50, 52
spirt.......... 149        houses, trees, &c. 338
Sce candle.               the sun....... 338
Lamp-glasses........  82       reflected......... 339
Land air cold........ 207      speed of.....  337, 338
Land breeze unhealthy 290       sudden, painful... 339
cools faster,than    Lighting fires........  46
water........ 207  LIGHTNING..........  11
Laplanders clad in iskin 171    affects iron & steel 35
Larve....     146' electric teleLATENT HEAT.......38, 95             graph..      36
Laundress........ 147          balls............   13
Laziness caused by want         barks & snaps trees 34
of food..  89     clouds..........   12
by heat....  92       comes from clouds  22
Lead, dullness of..... 234       "   from earth.  22
tarnish of....... 234      conductors.....  28
Leanness from starva-           dangerous........ 29
tion...........8....  6      followed by rain..  17
LEAvES absoib carbonic            "    by wind.. 17
acid........... 225     follows dry weather,
collect dew  une-            not wet........  33
qually......   192      forked..........  12
exhale oxygen... 224       fuses metal...... 82
green...... 372.kills animals....  14




LNDKX.                      47)
Page                         Page
Lightniag knocks down        Liquids heated...... 214
houses, churches,              not elastic.....  220
&c..............  29  Lisle thread gloves... 176
magnetic........  36  LONDON FOG......... 208
maims...........  14  Long flues......... 107
odor of..........  385     grass promotes cold 152
passes down the out-     Logs, two burn better
side of a tree..  20    than one..........  49
passes through the                See wood.
inside of animals  20  Looking-glass........ 343
produces fulgurites  35      a reflector........  343
purifies air......  33      reflects our image
rare in winter....  33         approaching, &c. 345
returning stroke..  23       reflects our whole
scorches trees....  34         person......... 345
sheet............  13  Lucifer matches...... 265
speed of.........  18  Lunar caustic........   454
straight.........  13  Lungs described......  224
summer.........  17
common in..  33  Mackarel scales, &c... 130
turns beer sour..  32  Mackintosh   prevents
milk sour....  30    cold............... 149
not old beer..  32  Madness from  starvanot porter...  32    tion...............      86
two flashes......  13  Magnetic effects of lightSee daneeru,  safet.       nin..        36
TLilac steel rusts......  233    agpies indicate weaprevented 233    ther............... 145
LIM, and water... 31, 37  Malt.252
burned..........   260  Malting............. 251
hot............. 260 Man a swimmer.    337
purifies bins 259, 389       fat, swims best... 337
"   sewers 259, 389        no bigger than a
quick or caustic.. 260         crow.......... 355
Lime-wash  for rooms 389  Marble.............. 454
Line of incidence.... 344  MARuc  comes in like a
of reflection.... 344          lion......... 287
Linen cool wear...... 171         goes out like a
dried...... 151, 295          lamb........ 287
Linseed  oil, boiling               dry  good, wet
point of.......  115               bad......... 288
LIQUEFACTION....... 121           flowers undesiraI.QuIDS............ 109             ble......... 288
bad conductors, 213          use of........ 287
coDled........ 215          wind cry...... 287




472                    INDEX.
Page                        Pa
Mares' tails..........  131  Mist i;creases distance. 1r1
Marsh gas........... 261       magnifies........ 141
Marsupium.......... 363        on windows...... 196
Mast of ships seen first 358    seems to rise.... 205
May flowers......... 288       vanishes at sunrise
MEAT covers......... 188                     205, 209
Meat liked in cold wea-         white..........  137
ther..........  90  Mixing not combining  30
loathed in hot....  91  Money hot in a pocket 158
roasted by reflect-     Monsoon.........280, 282
ors............ 180  Months, driest....... 307
taint removed.... 389           wettest...... 307
tainted by moon-        MOON, distance and size 356
light.......... 203      largest at horizon. 350
MECHANICA.L ACTION...  94       reflected in water. 349
Mercury of barometer. 297       seems flat........  356
boiling point of. 115        larger than stars 356
bright......... 235  Moonlight makes plants
concave...... 304              grow...... 203
convex........ 304           taints meat.. 203
its rise & fall, 303 to 308  MORNING breeze...... 290
rises from heat... 119        gray.......... 134
METAL collects no dew 193          rainbow....... 135
conductors....... 156         red....127, 134, 369
feels colder than             streaks........ 127
wood........ 158  MORTAR............. 260
hotter than wool 157        adhesive....... 260
fused by fire..... 121       crumbles...... 333
by lightning  32         hardens.... 260
good conductor... 156  Motes in a sunbeam.. 228
handles burn..... 156  Mould hardened by sun 153
reflectors........ 180  Mountains cloudy....  132
tea-pots......... 184       cold.. 181
Milk long in cooling.. 216      collect rain...... 316
soured by lightning  30       famous for echoes 384
Mineral springs....... 320      impede respiration 229
Miners' danger....... 264       noiseless........ 383
prevented 239  Muriate of soda... 454
Mirror.............. 343  Murky nights oppresMIST arrests sound... 381    sive..............  137
black............ 137  Musical instruments.. 379
cause of.... 204, 206                  flat.. 38(
differs from cloud 122        glasses.......  379
dew. 204          notes........ 379
fog.. 209         sounds..      3. 377




INDEX.                      473
Page                          Page
Myrrh antiseptic.....  889  Old  people lose their
power of walking 392
Nails for matches.....  95          spectacles for.. 362
Naves fitted on hot.. 118  One pot will not boil in
Near-sight.......360, 363            another...... 113
spectacles for 360        how to make it
Negative electricity...  22           boil......... 114
Negroes, why black... 178  Out-of-door work prowith black eyes Itq        duces hunger....  89
New kettles boil slowly 174  Owls prowl at night.. 342
Night allays hunger..  88         see in the dark.. 341
exhilarating...... 137       sleep all day.... 341
oppressive....... 137        screech before rain 141
produces cold....  88  Oxalic acid.......... 396
rainbow at....... 135  Oxide of copper......  233
warm, when cloudy 189             iron......... 231
Nimbus clouds....... 131             lead......... 234
Nitrate of silver...... 454  Oxide of platinum.... 235
Nitric acid.....30, 33, 454          potassium... 236
Nitrogen............  42             silver........ 234
expired....224, 239            sodium......  236
of air.......... 221  Oxidised............ 222
Nitrogenized.......  254  Oxygen..............  41
Non-transparency..... 373       exhaled by leaves 226
North wind cold...... 281        heats the blood... 223
dry...... 284        in the blood.      238
North-west wind  dry 286          inhaled.......... 222
299       makes blood red.. 223
Northern lights...... 135          "   fuel burn.. 220
Notes, bass........... 379       of air...........  96
fiat............ 380       its use...... 22(
sharp......... 380        supports combustreble..........  379        tion........ 97, 2201
November rainy......  289        sustains life...... 221
Ozone...............  35~
Odor of electricity....  35
Oil, elements of......  74  Paleness............ 222.
linseed, boiling point     Palmer's candles....  80o
of............... 115  Paper burns.........  46
of turpentine.... 115            not always 49, 57
of vitriol........ 454      extinguishers....  79,
Oiled paper transparent 373       oiled, transparent. 373:
Old people far-sighted 361       puckers from wet. 317'
hold objects at a          used for kindling.  4M;
distance..... 363  Papillae............   392'




47 1                    INDEX.
Page                          Pace
FPats  piaLter of...... 454  Poison for flies        390
Parlors smell of smoke       Poker draws up fire..  56
in summer........  71           hot against a stove 173
Partition walls to arrest         cold on a fender 161, 173
sound............ 382           how  to  carry  it
Pea-soup fog......... 207           when hot...... 217
Peacocks forebode rain 141  Poker rusts.......... 232
Pearl divers deaf..... 139       rust of, prevented 232
PERCUSSION..........  94  Polar current........ 278
Perspiration...... 88, 197  Polish, use of....... 163
Petals............... 370  Polished metal tea-pots 184
Petrels............. 146  Ponds dried up...... 153
Petrifaction.......... 320  Poor averse to cleanliPhosphate of lime.... 265           ness..........  92
Phosphoric acid......  43         ventilation......  93
Phosphorus..........  65        lazy.............  89
PHOSPHURETTED HYDRO-         Pores of wood........  105
GEN,GAS...........  265  Porter, froth of.. 107, 248
Piano fortes.......... 379          set before a fire 107
Pickle tested......  335  Porter, stale......... 255
Pie with a clip......  116  Porter vats dangerous 245
full ofjuice......   116  Positive electricity...  22
Pigs squeak before rain 141  Potatoes, green...... 372
Pimpernel  forebodes                   yellow...... 372
rain............... 143  Potash, tartrate of.... 454
Pin puts a candle out 81  Potassium........... 236
Pine snaps in fire.... 105         burns in water 236
Pipes broken by frost 327  Primrose yellow......    371
Piston............   100  Prisms divide light... 364
PLANTS collect dew.. 192  Psalm  cxlvii. 16, illusforebode rain.... 143    trated........ 164, 311
grow out of walls 296  Pump handle cold.... 158
after moonlight 203          water hard.... 320
Plaster of Paris...... 454  Purple steel rusts.... 233
of stoves falls          its  rust prevent-.
away.......   118        ed............ 233
Plasterers cannot work       PUTREFACTION........ 253
in frost............ 334            differs   from
Plate warmer.... 177. 180             fermentation 253
Platinum, its ulse... 235  Putrefying bodies smell
nevei tarnishes 235                     253, 266
Ploughing   promotes
warmth.......... ]51  Quadrupeds swim.... 337
Plumbago........... 232  Quick lime absorbs carprevents rust 232    bonic acid..... 246, 266




INDEX.                      475
Page                         Page
Quicksilver bright.... 235  Rainbow colors reversed 367
extinguished 454  Rainbows, two........  366
Quiet precedes storm.. 139  Rain drops.              314
vary in size.. 314
RADIATION...... 182, 228  Rain-water smells offencools iron.... 228            sively..... 322
Radiators are absorb-                 fertilizing.... 324
ers.......... 182           not salt.....  23
bad...........   162          soft........ 321
Rags catch fire sponta-               stagnant.      323
neously..........   60           unpleasant... 322
especially candle-     Rainy months........ 318
ras........    61  Rare air bad for sound 383
Railway steamers..... 201  Rattling of kettle-lid.. 112
water for...... 237  Ray of light divi(led.. 364
BRAIN...........        13..... 1    Reading aloud produaffected by wind.. 315    ces hunger.........  88
after lightning....  17  RED color........    2,, 371
arrests sound.....  380       rose............ 371
cause of......... 209        sky......... 126, 369
cloudls bode...... 134       sun-rise.....  127, 134
cools air......... 150       sun-set.......... 134
differs from dew.. 208  Reflected light........ 339
dispels carb. acid.. 246  REFLECTION Of HEAT.. 179
falls in drops.....  314      in a mirror.... 345
fertilizing....   288, 315      in water....... 346
from passing clouds 315  REFLECTORS......... 179
heaviest in summer 318        help the roast... 181
least at the poles.. 313       keep kitchen cool 181
most in mountain-             not absorbers.... 180
ous places......  316      should be clean and
most in winter 289, 318            bright.. 177, 179
near the equator.. 318           " not be painted 177
not salt.........  323  R:FRACTION.......... 358
on dlust.......... 206  Refrangible.......... 126
cabbages...... 206  Resinous electricity...  -3
rose-leaves.... 20(6  Retina.............. 360
prognostics of'... 134  Returning stroke......    23
firol animals... 140  Reverberation....... 383
candles & fires 141  Rice for food.........  92
clouds...... 134  RIvEas flow slowest at
flowers...... 143           sides........ 324
purifies air....... 315         freeze unequally
sud(len change... 302                      328, 323(
RAINBOW....... 364:, 365          invert our image 3"e




476                    INDEX.
Page                        P
Rivers never frozen at      Running water pule...  a4
bIottom..... 328  Rush lights easily blown
not wholly frozen 3'9             out........ 78
shailow,  freeze               extinguished by
fastest......... 330          a pin....n..  81
seem shallower than     RUST................ 231
they are....... 359       prevented....... 232
warm if frozen.... 330     when most troubleRoast apples......... 103         some.......... 232
soft.....  103  Rustics healthy......  242
chestnuts........ 102  Ruts frozen.......... 326
Road dark fiom a light
room.............  340  SAFETY  IN  A  STORM
Rocks collect no dew.. 194          abroad.... 25 to 27
broken by frost... 326        at a slight disRoom cooled..... 150, 295         tance from a tree 25
currlents of air in a 270    best to  be wet 27
ventilated........ 295      in a carriage....  26
vitiated by a crowd 295       in bed..........  27
warmed  by fire... 240       in doors........  26
Rose red............. 371  Safety lamp.......... 263
Rosneath, echo of..... 385  Sailors rarely catch cold 150
Ross, Captain......... 381  St. Bride's church deRotation of earth.....  272    stroyed by lightning  30
Rotting leaves promote       SALT................ 454
cold......          152       and snow cold..39, 332
Rubbing..............  98        and  water  boils
Rubbing hands to warm              slowly......... 114
tllem..........  98       crackles in a fire..  49
melts ice.........  99      dissolves ice...... 332
restores suspended           dissolved by water 322
animation......  98         especially by hot
wood excites fire..  98           ater........... 323
&Se friction.            flavors water...... 322
Ruddiness...........   223      of lemons........ 454
Ruine, famed for echoes 383      retards boiling.... 114
Running   promotes               smelling........454
warmth......  87      white.........   372
in a storm dan-           water unfit for railgerons..   21             way engines.. 237
water freezes slow-         for wnashing.... 320
ly.329  Salts, Epsom........  96
water   makes.        Sand dazzling.......  374
rough ice.   33  Saucepan  boils  best
" oscillates..... 324    when black.......-   186




INDEX.                      477
Page                         Page
Saucepan boils slowrly       Shallow   wa;er  soonll
when new.... 185    freezes............ 330
lids should  be        Sheep bleat before rain 141
clean and bright 185             in a storm. 25
rattle......... 112         lie under hedges 140
Scald cured........... 149  Sheet lightning......  14
Scripture illustrated...  161  Sheets wet.......... 149
145, 311  Ships out at sea....... 358
Scum of fermentation.. 255          hull of, last seen 358
Sea-beacll healthy  in       Shirts of linen........ 172
the morning.... 290  Shoes cold when wvet.. 148
not healthy at night 290       hot when dusty. 181
Sea betore storm..... 139  Shot hot............. 101
gives out heat.... 292  Shower cools air......  150
heaves and sighs.. 139  Shutters dangerous...  24
less lhot than land. 275  Sick rooms purified... 389
not much heated          Sides of a pond covered
by sun........ 275    with leaves......... 388
Sea-gulls............. 146  Sight affected by sudSea-vapor not salt..... 154    den light........... 339
Sea-water easier to swim     SILVER meat-covers... 188
in than fresh... 335             should not be
heavy an(l salt.... 323              chased... 188
rarely frozen.....  331     nitrate of.......  454
"   gives cold.. 150       tarnishes........ 234
salt............. 323  Simmering..........109
Sea-waves........... 292  Simple clouds........ 128
Sedentarly pursuits abate    Singing of a kettle.... 110
hunger...........  89            of boiling water 110
SEEING in a glass...... 313        produces hunger  88
into a dark street. 352  Single magpie unlucky 145
"   light room. 340  Size diminished by disourselves in a small       tanc.............354
mirror........ 345  Skin, black, does not
the same object... 339          scorch........ 176
When used to dark-           white does....... 179
ness........ 340         itches before rain. 142
Sensation destroyed.. 391  Sky blue............ 126
of feeling... 391  Sleep  elongates  the
of taste..... 391        body.......... 390
Sewers purified by lime 259      body feels n At in.. 391
Shade cool........... 171       dreams in........ 391
Shadow in water... 345, 3t46     ears hear not in... 391
Shadow larger as object          eyes sqe not in... 391
approaches a light.. 852       mind wills not ir.. 391




478                     INDEX.
Page                         Page
Sleep, tongue tastes not     Soap-bubbles.......   368
in................. 31           ascend........ 325
Sleet................ 310          change color... 368
Slit chestnuts......... 103  Soapy water bubbles.. 325
Smelling salts........ 454  Soda, muriate of'..... 454
SMELLS in wet weather 143          water..........    247
of bins and sewers 258           "  acid.....    248
church-yards... 265  Sodium............  236
putrefying bodies 253      decomposes water 236
SMOK..............45, 62  Soft soap............ 321
ascends........  62         water for washing 321
curls............  62  Solids............... 109
falls............ 144  Sonorous things..... 377
" downachimney  65  Soot in summer......  71
offiresh coals.....  45     on ceilings.......  71
candles........  81  Sooty kettles........ 174
lamps diminish-        SOUND.............. 377
ed by a glass.  83       affected by firost.. 381
red-hot coals...  45                   heat.. 381
rises............ 107       arrested by mist.. 381
useful in cooking.. 186                  wet... 380
Smoky chimneys.....   63          diminished by rarity
See chinmncy.               of air.......3..  83
Smoke jacks.......... 108       heard best by night 381
Smouldering wicks....  56                in a fiost 380
SNOw................ 309        inaudible on mounarrests sound..... 380        tains.......... 383
bad conductor.... 311        velocity of...... 377
cause of......... 310  Sounds musical....   377
falls in winter.... 310        prevented firom
" not in summer 312              passing firom
like wool......... 164            room to room  381
nourishcs the earth 311  Soup long cooling..... 215
on mountains..... 312  Sources of heat.. 9 to 15
soon melts beneath       South wind rainy 285, 800
a hedge or wall 191                warm.... 285
use of......    310  South-east wind rainy 286
warm............   310  Sparks from a fire.... 105
mixed  wVith salt,                   a flirt.... 196
cold... 33                         a horsewhite.......... 31                    shoe...  97
Soap................ 321  Spectacles........... 361
cleansng........  321           black........  376
hard, soft........ 321          blue.........  375
yellow..          321           for aged......362




INDEX.                      479
Page                          Page
Spectacles for near sight 860  Steam, why visible.... 112
Spectrum.......... 3877         what becomes oW' it 113
Split bells........... 378  STEEL affected 5y light.
Sponge swells when wet 316            ning..g....   36
SPONTANEOUS COMBUS-                 and flint make a
TION... 60, 84     s      park........ 96
of forests...   99       purple........ 233
Spoons become dull... 234           rusts.......... 233
bent in water.... 359                prevented 233
discolored byeggs 254  Stick  burnt makes a
retard boiling... 113    circle of light...... 374
Speaking produces hun-       Stillness before a storm  139
ger................ 88  Stirring cools broth, &c. 228
Spray white.........  371  Stockings difficult to
Spring, best late..... 288    draw on when wet.. 317
crumbles the earth 333  STONES broken by frost 326
bracing........ 140            cold.......... 159
verdure........ 372            collect no dew 193
Spring water cool.... 171           snap in fire.... 106
cc  "i   sparkles. 249            unfit for fuel..  49
Springs prevent freez-       STORMS.............   139
ing................ 331         direction of......  34
Sprinkling to cool rooms 150      distance of, told 16, 19
Stagnant water....... 323        follow dry weather  33
full of worms 323       places of danger in  19
Stale beer, &c. (see beer) 255       "     safety in  26
Stars, distance and size          prevail in summer
of............. 355          and autumn....  33
invisible by day.. 342      rare in wet weather 34
seem  flat........ 356  STOVES  crack  when
seen in a well.... 342          lighted...... 118
seen on mountains 350          when cooling.. 118
twinkle........  374        of bricks...... 163
Btarvation........... 86         on a floor.... 54, 217
produces dirtiness  93       rust.               240
laziness  89           most in  winleanness  86              ter........ 232
madness  86            not often.... 232
STEAM............... 122            prevented.... 232
engines burst.... 217       settings fall away 118
invisible.... 112, 216      smell of sulphur..  59
of a kettle.'....... 216     smoke..........  69
"  locomotive... 201        close............  62
pipes should not be          warm a room...   21
black......... 184  Strata of air.......  1




480                    INDEX.
Fage                        Pae
Stratus clouds........ 129  Summer allays hunger  91
Straw covered over brick-         clothes fior..... 175
work........ 334         creates dislike of
over trees...... 334            grease...   91
" water-pipes 334           "love of fiuit 92
Streets dark from a light          lightning.....   17
room........ 340  Sun-beallms full oflmotes 228
seem to meet at       SUN afflcts eyes...... 375
bottom...... 354       dazzles.......... 340
watered.....   150       dulls fire........  53
Striking iron makes it           hardens earth.....153
hot............  94          largest at horizon. 350
Struggling in water dan-         not seen in a well. 348
gerous..            336       radiates heat..... 183
Stucco peels off in frost 333    reflected in Nwater. 349
Sublimates.......... 454        seems flat........ 356
Sublimation......... 454        source of heat....  10
Sudden light painful.. 339  Sun-rise red...... 127, 134
SUGAR.............. 249  Sun-set gray......... 135
anhydrous....... 250           red....... 133, 135
ferments......... 249         yellow.... 133, 134
at top of tea melts     Super-acetate of lead.. 454
quickly........  389  Suspended  animation
flavors water..... 322   Irestored(...........  99
left at the bottom      Swallows fly low...... 144
of a cup melts        Swan dry in water....   206
slowly......... 388  Sweet-wort needs yeast 252
makes alcohol...  250  Swimmers sink.......   336
"  carbonic acid 250  Swimming.......337
melted by water.. 322           in the sea.... 335
"  especially by      Syrup, boiling point of 115
hot water. 322
of lead..... 454  Table salt............ 454
retards boiling... 114  Tainted meat cured 72, 389
stirred melts quick-            in moonlight. 203
ly............. 388        water........., 2
white.......... 372  Tallow.............   74
Salphate of lime.. 320, 454  Tarnish............. 233
magnesia. 454  Tartar emetic.          454
soda.     454  Tartrate of potash.... 454
zinc...... 454  Tarts hlave a cup inside 116
8ulphuric acid....... 454      full of juice...... 117
and water  37  Taste...............  392
boils 115  TEA cooled by }blowing 228
Sumrrer, aMr in......   293           by stikring 228




INDEX.                     481
Page                         Paro
Tea cooled in a saucer 153  Tin-blowers reflectors la
green, deleterious 390          See reflectors.
poison for flies 390  Tinder blown........  96
TEA-POT, bright metal. 184  Toast and water.....  73
tarnishes 234       dry, for the sick..  73
black earth..... 184  Tomb-stones frosted    177
preferred by       Tongs rust......... 232
some..... 184               prevented.. 232
set on a hob.... 184  Tools hot from use...  99
Tea-spoons tarnished. 234  Trade winds......277, 280
by eggs 251  Transparency........ 37g
Telescopes.            357  Treble..........   379
Tempest........ 139  TREES barked by lightaffects weather 305            ning........  34
Sce storms.                 collect dew.... 190
Thaumatrope........ 374             covered  with
THAW affects barometer 308            bass, &c..... 334
cold.......        331          look  more disdulls fire.......   55           tant in a fog.. 141
Theatre dangerous....  25          not frost-bitten. 211
Thermometer....119, 296            promote warmth 152
Thick   clothing   un-              purify air...... 242
healthy............ 154          shade of, cool.. 171
Thread gloves cool.... 176  Trefoil forebodes rain. 143
THUNDER............   15  Tube of barometer.... 297
after lightning....  17  Tubs dried up..... 153
bolts (seefulgurites) 17  Tumblers (see glasses.)
deep growl......  16  Twilight............. 370
distance of, told.16, 18  Twinkling of stars.... 374
followed by rain..  17  Two eyes............ 343
wind.  17          "   see single.. 343
irregular roar....  15      logs burn best....  49
one crash......  15
rolling..........  17  Unslit chestnuts...... 103
See danger, safety, storm.   Use of barometers.... 298
Tigers prowl by night. 342          clouds.....  132
see in the dark. 341         smoke in cooking 186
sleep all day... 341        snow......... 310
Tiles broken by frost.. 326
Timber charred...... 73  Valley chimneys smoke  61
Tin-blowers.......... 70  VAPORIZATION........ 12'
foot-warmers.... 162  Vapor a conductor....  25
" covered  with                 forms fog and
flannel... 162             cloud...... 209
plate-warmer... 177              of a carriage. 197
21




482                     INDEX.
Page                         P
Vapor of a room.... 196  WATER (see rain)..... 
of sea not salt 154       and lime...... 31, 37
Varnish to prevent rust 232       and sulphuric acid  37
Vats fatal............. 244      ashes soften...... 321
Vegetable and animal              bad conductor 161, 214
life dependent...... 225      boiling.. 115, 213, 215
Vegetables absorb car-                bubbles. 111, 214
bonic acid... 225           rattles....... 112
agreeable in sum-               runs over.... 111
mer.........   91           sings........ 109
collect dew.... 192       cleans dirty linen. 321
cool the blood..  92       cold............. 160
exhale oxygen. 224         converted to steam
Velocity of clouds.... 294                     121, 319
light...... 338      cools slowly...... 207
sound..... 384        deep, freezes slowly 330
wind...... 294       dried up in summer 153
Vent peg.......... 255           elastic........... 253
VENTILATION......    93, 295     expands by frost.. 327
sought by  the                      by heat.. 327
well-fed.....  93       extinguishes fire 57,106
sought not by the               not always 57. 58
ill-fed.......  93      flat when boiled.. 257
Verdigris............ 454       fluid............ 319
Vertical sun......... 273       flowing, pure..... 324
Vinegar antiseptic.... 389       for washing.. 259, 320
distilled...... 454     freezes at the surViolets blue........ 371           face.......... 328
Violins musical....... 378      fresh, sparkles... 260
Vitreous electricity 11, 23       frozen by ether.. 334
Vitriol, oil of........   454             air-pump 335
white.. 454        fuel.............  58
furr of........... 237
Walls to arrest sound. 382      hard............ 320
wet in winter.... 199       agreeable to drink 260
"  in a thaw.... 199        unfit for washing 320
Want connected with              how preserved cool 179
dirt...............  92                  hot 179, 187
Warm clothes........   175      heated.......... 213
some things more           intenses fire.....  57
than others... 155       inverts images... 346
Warming rooms...... 217         kept hot......... 216
Wash-hand basin....   160       melts sugar, salt,
Washing, water for.... 259             &c....... 322
should not be hard 320           especially hot 373




INDEX.                      483
Page                         Page
Water mixed with salt,       Weather, prognostics of 130
boils slower.... 115         told by barometer 296
needfil for ferment-           rules for....... 299
ation........ 255  Weather-toys........ 317
not heated above         Well, stars seen in.... 348
boiling........  215      sun not seen in... 348
of a spring cool.. 171  West winds...... 201, 285
oscillates........ 324  Wet clothes give cold 148
pump, agreeable.. 260            safe.........  27
hard........ 319        feet dangerous... 148
purified.........  72       finger cold.....   148
purities bins, &c.. 259     indications of 131 to 136
reflects sun by a spot 3650  kindling........  48
moon by a path 349         night oppressive.. 137
running, keeps pure 324      sheets.......... 149
salt, bad for wash-          summer, cold wining........... 320          ter............ 151
shallow,   freezes           weather offensive
fastest.........   330                    137, 140
simmers......... 109  Wettest months...... 307
slackens flame....  58  Wheels catch fire.....  98
soft...... 259, 321      greased..........  98
best for washing 321       kept cool by water 153
sparkles......... 249  Wheel-ruts fiozen.... 325
stagnant......... 323  Wheelwright........ 117
full of worms 329  W1IIrF:.............. 371
stale............ 257        blisters.178
swells with boiling 110      body linen.         174
will  not bubble             crust on clothes.. 154
without soap... 324        dresses for summer 175
warm when frozen 330           "not fit for winWater-pipes broken by                   ter........ 175
frost.......... 327       mist............. 138
covered with litter 334     vitriol.......... 454
Watering plants by the       WicKs,  cotton,  need
sancer...... 388          snuffing.......  80
streets........ 150       gas of.......... 262
Waves............... 292         have a nob when
Wax................  74             long..........  80
candles need no            not upright when
snuffing.....  80         long..........  80
Weather  affected  by            Palmer's, need no
tempests.... 305          snuffing.......  80
affected by weight         rekindled,4 a ickly 55, 58
of air....... 297       smoke.........       81




184                   INDEX.
Se carndles.        Windows rattle......37
Will o' the wisp, (sce      Winc-glasses(seeoglasses.)
i&g'is fatl us)... 266  Wine, fermentation of 249
WIND........ 268, 296        made without yeast 254
affects barometer. 299  Winter clothing...... 164
"  clouds 125, 127  Winters less severe... 157
after lightning....  17  Winter cold.......... 151
altered by clouds.. 276      promotes hunger  90
"  by electricity 127  WlSDOM  OF GOD 153, 16,3,
"' by seas..... 275    193, 195, 225, 283, 289,
always blows..... 272                     328, "333
brings clouds..... 132  WooD ashes soften water 322
" dry...         286     burns..........  46
"  rain......  286         " spontaneously  59
cause of.....    268, 272   charred..........  72
changes the shape           hot at one end, cold
of clouds.. 123, 125        at the other....  55
cold........ 17. 184      ignited by fiiction  97
dispels clouds 125, 133     kindling........  47
"   fog.......    210       "    dry.....  49
draws up fire.     55           "    wet....  49
dries linen....... 295     made incombustible 49
effects on air.....  268    sends forth sparks 105
feels hotsometimes 169      snaps........... 103
increases clouds.. 125      two logs burn best 49
males  barometer            will not melt..... 122
fall........... 299  Wooden handles.....  156
makes  chimneys         Woodpeckers cry before
smoke.....   67, 108    rain.............. 141
near mountains... 276  WOOL bad conductor.. 156
of a morning.....  289       collects no dew.. 193
of an evening....  290      warm...... 165, 311
prevents dew.....  191  Woollen clothing..... 164
velocity of....... 293       kettle holders.. 157
regular.......... 277  Work produces hunger  87
S&e monsoou, -iorth, sout,,
west, 4c,  trade-winds,  Yeast..               215
+ce.                           makes lighlt brelad 275
Winding passages famed           not used in wine 245
for echoes......... 384       usedin brewhig.. 215
Windows blazing with        Yellow flame gives best
the sun....... 347         light.........  51
not at noon..... 347       soap........  321
covered with frost 197      sun-set sign of wet, 1]33
e":' mist 196
carriage, dull.... 197  Zig-zag lightning..    12




INDEX TO PART III.
Page 
Above proof.......... 449  Books  discolored  by
Abundance of dew a              age..............  423
sign of fine weather 392  Brazil pebbles........ 438
Acetic acid........... 446  Bread............... 426
Acid stains removed.. 420          full of eyes.... 399
Acryle............... 447         hard from age.. 410
Agate............... 438          mouldy........ 427
Air rots wood........ 429         new, indigestible 410
Albumen............. 407  Bridges increase sound 433
Ale................. 443  Brine preserves meat. 407
Alkali............... 420  Brown paper burns well 393
Alkaline phosphates.. 441              sticky fiom
of meat 407               rubbing.. 405
Amethyst............  438  Brown stout......... 443
ANrID('rES FOR P)ISONS 452  Brushing hair makes
Apples soul'..........   446    the head itch.... 395
Aqua-fortis, antidote for 452  Burning glass ignites
Arsenic, antidote for 452        paper............ 893
Burton ale......... 443
Baking  dough  into         Butter hard from cold 412
bread............ 426         soft fiom heat. 412
Barometers   measure
heights.......... 406  Cairngorum.....    438
Barytes..............  451  Candescence.....   431
Beer................. 443  Candle flickering..... 395
sour from bad cork-     Candle-wick smell.... 447
ing............ 444  Carbonic acid........ 439
Below proof..........  449  Caries.............. 447
Binoxide............ 394  Casein........... 44, 443
Birds kept in feathers 428  Caves increase sound. 413
Black earth turns red 402  Cellular fibre......... 438
Blackness from  decay 419  Cellulin.............. 414
Block-tin............ 451  Chalcedony.......... 438
Bloodstones.......... 438  Champagne.......... 448
Blue  looks green by        Chandelier lustrous... 404
candle-light...... 393  Chaps and chilblains.. 402
Blue sky............ 439  Cheese...............   425
Boiled lobster red.... 419  Chlorate of potash.... 417
shrimp red.... 429  Chloride of lime...... 440
Boiler bursts........ 395  Chlorine, antidote for. 442
Boiling meat......... 402  Chlorophyll......... 411
stale milk, curdles 424  Chlucky stone........ 438
Boiling wood makes it       Cllurning makes butter 425
soft.............. 437  Claret............... 448




486                     INDEX.
Page
Clothing warm if loose 399  Dentine............... 
Clouds do not bide light 439  Dextrin.............. 427
Citric acid.......... 446  Diastase............. 427
Citrons sour......... 446  Double doors increase
Cold affects skin...... 402       heat............. 397
Color................ 396  Double  reflexions  in
destroyed by dark-            glass............. 4.38
ness........... 396  Dough...............  426
faded by sun..... 425            mad. e bread.... 426
Contagion prevented.. 442  Drops of water spread. 406
Copper bursting....    395  Dust laid by night.... 401
Copper cankers...... 436
Cork of soda-water flies 401  Effervescing draughts. 420
pops 401  Egg tarnishes silver... 423
Cornelian............ 438         tarnish removed by
shines, if wet 397          salt........... 422
Corros've sublimate.., 440  Electricity sticky..... 405
antidote for 453  Essential oils......... 436
Court buttons........   415  Explosive lucifers.... 416
Cream made butter... 425  Explosion of gunpowder 442
Creasote............. 444
for tooth-ache... 447  Fat solid....            411
to remove taint. 444  Ficus................ 448
Crombs made by boil-          Filaments........... 437
ing.............. 437  Fire destroys steel-pol-.
irystal..............     438        ish............ 413
Cup filled beyond brim  t55         revived by brush 398
not if'edge be wet 415                by poker 398
Curdling milk........ 423          quenched by sulCurling   paper  with                 phur......... 421
knives........... 418          warps wood....   425
Currants hard........ 443  Fire-works........... 451
ripe, soft.....  443  Fish luminous........ 439
Curtains I)romote heat 397  Fixed oils........... 436
Flag-stones loose in frost 396
Damp lucifers........ 417  Flickering of candles.. 395
of decay....... 410  Flint................ 438
Darkness spoils color. 396  Flowers bend to sun.. 429
Decanter-stopple sticks 418  Fog rrmakes sun red.... 393
Decanting liquor, gur-        Frost loosens pavement 396
gles............. 416   Fruit, antidote for.... 453
Pecay, see r0t.                Fungus.............. 427
black..........  402
Decay of teeth........  447  (t lasses filled above brim 415
tkeory of.      403          not if wet...... 415




INDEX.                       487
Page                           Page
Glazed pictures some-         Ink-spots removed... 436
times invisible.... 401             turn yellow 394
Glazier mending a win-        Interstices............ 406
dow............. 404   Iodine, antidote for... 451
Glue adhesive........  432  Iris ornaments........ 415
Gooseberries lhard.... 443  Iron bends...........  430
soft, if ripe 443      galvanized....... 450
sour...... 446        hisses........... 436
Grapes sour.......... 446          melts........... 431
arease spots removed. 436           rusts.....        398
Greasy paper unfit for              turns red........ 431
writing........... 435         turns white...... 431
Green fire-works......451  Itch................. 440
fruit hard...... 443  Itching caused by hair
wood rots...... 413        brush............ 395
Grindstone wet......  425
Guano............... 438  Jeweller's gold....... 450
Gum adhesive........ 432
Gunpowder explosive. 442  Knife  sharpened  by
Gurgling explained... 416          grindstones....... 426
Gutta percha.........  448
Lactic acid........... 424
Hams smoked....... 444  Lamb soon taints..... 409
Hard bread......... 410              tender......... 408
soap........... 445  Larks roasted with lard 407
Hartshorn removes acid        Lather............... 399
stains........... 420  Laudanum, antidote for 452
Heat warps wood..... 425   Lead differs from solder 450
Hock................ 448  Legumine........... 445
Horn shavings opaque 404  Lemons sour......... 446
Humus.............. 436  Ligneous matter...... 414
Hydrate............. 436  Light, when cloudy... 439
of the carbonate       Lightning  conductors
ofcopper.... 436        pointed.......... 421
Likeness reversed in a
Ice in India.......... 434        glass............. 417
Ice pits............ 434  Lime for manure...... 438
Indian houses kept cool 435  Lime-juice cures scurvy 440
Indian-rubber........ 448  Limes sour.......... 446
erases pencil marks 429  Linen starched....... 421
Indian-rubber sticky.. 405  Liquor gurgles....... 416
Indigo blue, white.... 420  Locomotive whistle... 412
Infection prevented... 450  Lucifer matches...... 416
Ink................. 394            spoilt by damp. 417
Ink-spots black...... 394  Lustres variegated.... 40?




488                     INDEX.
Page                          Pan
Manure for land......  438  Oxalic acid..........  445
%arking ink......... 449         antidote for...... 452
Marl for manure..... 438          removes ink-spots 436
Meadows reverberate. 433  Oxide of potassium... 445
Meat,  directions  for
boiling........... 408  Paint blisters......... 409
preserved...... 444         preserves wood. 413
tough when old 408           prevents rust... 398
overcooked 408  Pannary fermentation. 410
boiled in cold     Paper curls by scraping 418
water.... 408          discolored by age 423
putrefies   from       Partridges roasted with
change...... 428         lard........... 409
damp.. 428  Paste adhesive.......  432
heat... 427  Pencil marks erased.. 429
Mice destroyed....... 442  Peroxide............. 394
Milk boils over...... 400             of iron red.. 403
quickly... 433  Pewter.............. 450
burns..........   4.32  Phosphate........... 407
curdles........ 423              of lime..... 440
by rennet 424              of meat.... 407
sourfrom boiling 424  Phosphoric acid...... 439
heat... 424  Pictures glazed invisikeeping 424        ble.............. 451
Molecules............ 431  Plants bend to sun.... 429
Moon shadow strong.. 420  Plants white if kept in
Mother of pearl...... 414        the dark......... 411
Mouldy bread........ 437  Plaster of walls peals off 403
Mountains meted..... 406  Points discharge elecMutton fat hard....  411         tricity........... 422
PoisoNs, antidotes for 452
Oak bark contains iron 419  Polish of steel destroyOak struck by lightning 419       ed by fire........ 413
Oar bent in water.....  392  Pop-guns pop...    412
Oil liquid............ 411  Porter. dark.......... 453
prevents  water        Port-wine.....   448
freezing...... 432  Potatoes boiled...... 422
thick in winter 411  Proof spirit..........  448
used on grind-         Protoxide....... 394
stones....... 426            of iron black 403
Oleine............... 411             of copper... 436
tEnanthate..... 447  Prussic acid, antidote
of ethyle.. 447         for............ 453
Oranges sour......... 446  Putty dancing........ 404
Overboiled meat tough 408  Putrefaction.......... 424




INDEX                      489
Page                         Pus
Putrid fish luminous.. 439  Sesquioxide of irlon... 394
Pyroligneous acid..... 444  Shadowofmoonandsun 420
dark.......... 443
Quails roasted with lard 409  Shear steel........... 449
Quartz............... 438  Sherry............... 448
Shrill sounds....... 412
Railway whistle....... 412  Shrimps red......... 420
train passing a bridge    Silent lucifers....   416
or meadow...... 433  Silica................ 438
Rain brings down cold 435  Silver hotter than nickel 448
Rats destroyed....... 442       tarnished by egg,
Red earth............ 403        cleaned........ 422
fireworks........ 451          by salt cleaned 437
Reflection in a glass        Sky blue.............  439
double.......... 438  Small beer........... 443
reversed 417  Smell of sick rooms reRennet.............. 425        moved........... 442
curdles milk... 424  Smelling-bottle stopple
Rhubarb sour........ 446        sticks............ 418
Ripe fruit soft........ 443  Smoked meat........ 444
Rock crystal....... 428  Soap made of fat..... 445
Rooms kept warm by           Soapy water lathers... 399
curtains.......... 397  Soda in tea......  444
Rot........ 413, 429, 441  Soda water cork flies out 402
Rotting leaves hot.... 410                 pops.. 401
Rust................. 398  Soft soap............ 445
prevented by paint 398  Solder.............. 450
Sorrel sour........... 445
Sails of mill turn...... 396  Sound.............  412
Salt................. 423         heard  furthest
beef produces scurvy 440           on sea...... 406
remedy... 440          louder in caves. 413
meat not nutritious 407          silenced by touch 399
meat needs vegetables 408  Sour milk............ 424
removes tarnish from                curdles...... 423
silver............ 422  Sponge cleans a slate. 400
wine stains..... 442  Spores, Sporules......  427
tarnishes silver..... 437  Stains removed....420, 436
tarnishes removed.. 437  Starch glazes linen.... 406
Salts preserve meat... 407         stiffens linen... 421
wood... 414  Stars twinkle......... 400
Sapid................ 409  Stearine......... 411, 446
Scraped paper curls... 418  Steel made fiom iron. 449
Scurvy.......... 440, 441        made brittle.... 434
Sea luminous......... 440  Stirring a fire....... 399




490                   INDEX
Page                       Pan
9topples stick........ 418  Vegetables black from
Strands.............. 437     decay............ 419
Strontian............ 451     essential with salt
Stucco falls off........ 403    meat........... 408
Sulphate of lime...... 441    prevent scurvy... 407
soda...... 423     wet from decay... 403
Sulphur quenches fire. 421  Verdigris............. 436
Sulphuret of silver.... 423        antidote for.. 433
Sulphuretted hydrogen 442  Vinegar sour......... 446
Sulphuricacid........ 421  Volatile oils.......... 436
Slphurous  acntidote for....  452  Walking-stick crombs. 437
Sulphurousacid   1Water................ 388
Sugar of dough....... 4103
Sun fades colors..... 426      freezes ifexposed. 431
sooner than milk 431
red in fog........ 393           when boiled 432
warps wood...... 425      hisses on fire...  430
Tainted meat......... 428      rots wood         429
Tamarinds sour....... 446
Tannate of iron.....     4       spreads on cloth.. 406
Tannicate of iron d......394, 436  used on grindstones 426
Tanning leather......  46  Warm clothing.....,. 397
Tanning leather...... 44609
Tarnish of silver...... 437       d.409
removed, 423, 437
of zinc 2... 436      makes cotton strong 437
soft...............  434
Tartaric acid......... 446so
Tea.rtaric acid....   446  Wet of decay......... 403
improved by soda 444  Wet sponge cleans slate 400
improved by soda 444  White lead..........  450
in Tartary........ 445       leaves.........  411
rashes to a spoon. 415  Whistle of locomotive. 412
Teeth decay.......... 447  Windows mended..... 404
Windmill sails........ 399
Tooth-ache, cause of.. 447  Windmill sails.      44399
Touch till fsounsour from corking 444
Touch stills sound.... 399
stains removed.... 441
Tough ineat.......... 408      strength of....... 448
gre-ase sremoves     Wood, decay of....... 441
rease spTwinklingots...... 43600  flexible, if boiled. 437
Twinkling............ 400
preserved by paint 413
Unseasoned wood rots 413                 by salts 414
rotted by air..... 429
Veal soon taints..... 409       warped by eat.. 425
ener.      40  Warts cured......... 453
tendel.......4... 408   tarns.. 4.3
Vegetable fibre....... 414  Zinctarnish......... 43




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Illustrated. 88 cts.
THE CHILD'S OWN
TREASURY OF FAIRY TALES.
Containing the best and most popular Fairy Tales.
Beautifully Illustrated. Square 16mo. $1.25.
THE MAGIC RING,
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HOME STORY BOOK.
A Collection of unexceptionable Tales by MISs STRICKLAND and
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Square 16mo. 75 eta.
TIE N BOY'S 3BOOK OF
INDIAN BATTLES & ADVENTURES,
WITH ANECDOTES ABOUT THEX.
10 Engravings. 88 cts.




Tn ANOU AIIRlA.IIV  JUIENILES,
Just Published.
TRAVELS AND SURPRISING ADVENTURES OF
BARON MUNCHAUSEN,
nlustrated with 11 full-page, and 22 smaller Engravings. 88 eta
THIE LIFE AND ADVENTURES OF ROBINSON CRUSOE.
By DANIEL DE FOE, including a Memoir of the Author, with anD
Essay on his writings. Printed on tinted paper, and beauti
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i",ruB B L PIF8P1RE    0. a II D A N
on,
BIBLE EXAMPLES OF EVERY-DAY TRUTH.
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BLIND ARTHUR, AND OTHER STORIES:
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LILIES FROM LEBANON;
OR,
SCRIPTURE SKETCHES.
By MIss GRAHAM, embellished with 8 beautiful Wood-cuts
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FAVORITE FAIRY TALES
YFOR I;ITTLE:FOLES.
With 70 Illustrations by THWAITES and others, engraved by the
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ALWAYS HAPPY;
OR
OF
FELIX AND HIS SISTER SERENA,
NEW YORK:
PUBLISHED BY JAMES MILLER:
SUCCESSOR TO C. S. FRANCIS & CO.,)
522 BROADWAY.
MDOCOLXIV.




TREASURY OF FAIRY TALES,
Embracing the best and most popular of the old
fashioned Fairy Tales, and Illustrated
in the highest style of Art.
FAVORITE FAIRY TALES
FOR LITTLE FOLKS.
With 70 Illustrations by THwVAITES and others
POPULAR FAIRY TALES
FOR LITTLE FOLKS.
With 60 Illustrations from original designs.
This series of Fairy Stories has for generations
been listened to and read by children with a delight which all others have failed to afford them.
That these editions may be more perfect than
ny others extant, they have been embellished with
exquisite specimens of high Pictorial Art, from
which children may derive those correct ideas that
will mature into the beautiful and grand.




AMY DEANE,
BY VIRGINIA F. TOWNSEND.
ILLU STRATED.
NEW YORK:
PUBLISHED BY JAMES MILLER,
(SUCCESSOR TO C. S. FRANCIS & CO.,)
522 BROADWAY.
1864




NEW  ANI) ATT'LACTIVE
JUST PUBLISHED BY JAMES MILLER.
THE DREAM OF LITTLE TUK,
AND OTHER TALES.
BY IIANS CHIZISTIAN ANDERSEN.
Illustrated. 50 cts.
THE STORY OF CECIL AND HIS DOG
Illustrated. 88 cts.
lanbine, anb tle 6arlanb  of  acbrlIstings.
illustrated. (;3 cts.
RIGHT AND WRONG, & THE GOLD CROSS
Illustrated. 63 ets.
ALWAYS HAPPY;
Or, Anecdotes of Felix and his Sister Serena.
Illustrated. 63 ets.
The Well ill the Rock, and Other Stories
BY VIRGIYIA F. TOWNSEND.
Illustrated. 88cts.




AMY DEANE,
AND OTHER STORIES.
BY VIRGINIA F. TOWNSEND.
Beautifully Illustrated.
The interesting character of these stories, and
the high moral tone which, without becoming
tedious, pervades them all, recommends this book
in a special manner to our Young Friends. The
Publisher is satisfied that on perusal it will be found
to compare favorably with any of the tales of Mary
Howitt, Miss Edgeworth, Mrs. Hofland, &c., &c.
THE MAGIC RING,
AND OTHER ORIENTAL FAIRY  TALES.
ILLUT/STRATED.
The same simplicity of style and elegance of
language, which have rendered the "Arabian
Nights" so justly popular, will be found in thl(
above bcok, which the Publisher now offers, and
which will, he is confident, when better knownl,
take rank amongst our most Popular Juvenile
JLiterature
THE FAVORITE SCHOLAR.
By MARY H0WITT.
AND OTHER TALES.




PALEY'S
EVIDENCES OF CHRISTIANITY,
With Annotations
BY RICHARD WHATELY, D. D.,
ARCHBISHOP OF DUBLIN.
One Volume, Octavo, Cloth, $1.75.
The Publifher feels great pleafure in calling the
attention of the religious and thinking portion of
the community to his very handfome edition of this
work of the celebrated PALEY, a man remarkable for
vigor and clearnefs of intellect, and originality of character, and acknowledged by all to be the greatest
among the divines of his age, and without a fuperior
fince the days of the early fathers of the Protestant
Church. To add to the value of that which is intrinfically valuable in itfelf, the volume now presented
to the American Public is enriched with "Annotations" by the celebrated Dr. Whately, Archbifhop
of Dublin, than whom there is no clearer thinker or
more powerful writer in the Proteftant Hierarchy of
our day..Also, uniform with the above,
BACON'S ESSAYS,
With Annotations
BY RICHARD WHATELY, D. D.
One volume, Octavo, Cloth, -- -    $2.50.
JAMES MILLER, Publifiher,
2zz Broadway, Ncv rorl.




A POEM,
BY PIHILIP JAMES BAILEY,
BAIRRISTER AT LAW.
1 volume, Blue-and-gold, $1. 00. 12mo, $1 00.
"It is an extraordinary production."-London Literary
Gazete
WORKS OF WILLIAM WARE.
Z E N 0 B I A; or the Fall of Palmyra. In letters of L
Manlius Piso, from Palmyra, to his friend Marcus
Curtius, at Rome. 1 vol., 12mo,    - - - $1.50
AURELIAN; or Rome in the Thlird Century. In
Letters of Lucius M. Piso, from Rome to Fausta,
the daughter of Gracchus, at Palmyra. 1 volume,
12mo, -  -             - - -       - -  $1.50
JULIAN; or Scenes in Judea.  1 vol., 12mo, - $1.50
JAMES MILLER, Publisher,
522 Broadway.