A. As the pupil of their eyes is _very broad_, the light of the fire
_pains_ them; and they keep shutting their eyes to relieve the sensation
of too much light.
Q. _Why do TIGERS, CATS, OWLS, &c. PROWL by NIGHT for prey?_
A. As these animals cannot see distinctly in _strong daylight_, they
_sleep_ during the _day_: and as they can see clearly in the _dark_,
they prowl then for prey.
Q. _Why do GLOW-WORMS glisten by NIGHT only?_
A. Because the light of day is _so much stronger_, 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 DAY-TIME?_
A. Because the light of day is so powerful, that it _eclipses the feeble
light of the stars_: in consequence of which, they are invisible by day.
Q. _Why can we see the STARS even at MID-DAY, from the bottom of a deep
WELL?_
A. As the rays of the sun never come _directly over a well_, but the
rays of the _stars_ do; therefore the light from those stars (in such a
situation) is more clear than the light of the _sun_.
Q. _What is the USE of TWO EYES, since they present only one image of
any object?_
A. The use of two eyes is to _increase the light_, or take in _more rays
of light_ from the object looked at, in order that it may appear _more
distinct_.
Q. _Why do we NOT see things DOUBLE, with TWO EYES?_
A. 1st--Because the _axis of both eyes is turned to one object_; and,
therefore, the _same impression_ is made on the ret´ina of _each eye_.
2ndly--The nerves (which receive the impression) have _one point of
union_, before they reach the brain.
Q. _Why do we SEE OURSELVES in a GLASS?_
A. The rays of light from our face _strike against the surface of the
glass_, and (instead of being absorbed) _are reflected_, or sent back
again to our eye.
Q. _Why are the rays of light REFLECTED by a MIRROR?_
A. Because they cannot _pass through the impenetrable metal_ with which
the back of the glass is covered; so they _rebound back_, just as a
_marble_ would do if it struck against a wall.
Q. _When a marble is rolled towards a wall, what is that path THROUGH
WHICH IT RUNS called?_
A. The line of the _angle of incidence_.
Q. _When a marble REBOUNDS back again, what is the path it THEN
describes called?_
A. The line of the _angle of reflection_.
Q. _When the light of our face goes TO the GLASS, what is the path
through which it goes CALLED?_
A. The line of the _angle of incidence_.
Q. _When the light of our face is reflected BACK again from the mirror,
what is this RETURNING path called?_
A. The line of the _angle of reflection_.
Q. _Why does our reflection in a mirror seem to APPROACH us as we walk
TOWARDS it, and to RETIRE FROM us as WE retire?_
A. Because the line _of the angle of incidence_ is always _equal_ to the
_line and angle of reflection_.
[Illustration: Here CA, EA and DB, FB are the lines of the angle of
incidence; and GA, KA and HB, LB are the lines of the angle of
reflection. When the arrow is at CD, its shadow will appear at GH,
because the line CA=GA and the angle CAB=angle GAB, &c.; and the same
may be said about the point D.]
Q. _Why can a man see his WHOLE PERSON reflected in a LITTLE MIRROR not
6 inches in length?_
A. Because the _line of the angle of incidence_ is always equal to the
_line and angle of reflection_.
Take the last figure--CD is much larger than the mirror AB; but the head
of the arrow C is reflected obliquely behind the mirror to G; and the
barb D appears at H.--Why? Because the line CA=AG and the angle
CAB=angle GAB, &c. The same may be said of the point D.
Q. _Why does a SHADOW in WATER always appear TOPSY-TURVY?_
A. Because the _line of the angle of incidence_ is always equal to the
_line and angle of reflection_.
[Illustration: Here the arrow-head A strikes the water at F, and is
reflected to D; and the barb B strikes the water at E, and is reflected
to C.
If a spectator stands at G, he will see the reflected lines CE and DF,
produced as far as G.
It is very plain that the more elevated object A will strike the water,
and be projected from it more perpendicularly than the point B, and
therefore the shadow will seem inverted.]
Q. _When we see our SHADOW in WATER, why do we seem to STAND on our
HEAD?_
A. Because the _line of the angle of incidence_ is always equal to the
_line and angle 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. (_See last
figure._)
Q. _Why do WINDOWS seem to BLAZE at SUN-RISE 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. _Why do NOT windows reflect the NOON-DAY rays also?_
A. They do, but the _reflection is not seen_.
Q. _Why is the reflection of the RISING and SETTING sun seen in the
window, and NOT that of the NOON-DAY sun?_
A. As the angle of _incidence_ always equals the _angle of reflection_,
therefore the rays of the noon-day sun enter the glass _too
perpendicularly_ for their reflection to be seen.
[Illustration: Here AB represents a ray of the noon-day sun striking the
window at B; its reflection will be at C:
But DB (a ray of the rising or setting sun) will be reflected 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.
[Illustration: Let BDEC be the well, and DE the water.
The ray AB strikes against the brick-work _inside_ the well; and
The ray AC strikes against the brick-work _outside_ the well.
None will ever touch the water DE.]
Q. _Why do we see the MOON reflected in a WELL very OFTEN?_
A. As the rays of the MOON are not so _oblique_ as those of the sun,
they will often reach the water. _(See next figure.)_
Q. _Why are the STARS REFLECTED in a WELL, although the SUN is NOT?_
A. As the rays of the STARS are not so _oblique_ as those of the sun,
they will often reach the water.
[Illustration: Here the moon's rays AB, AC, both strike the water DE,
and are reflected by it.]
Q. _In a sheet of water at noon, the sun appears to shine upon only ONE
spot, and all the REST of the water seems DARK,--WHY is this?_
A. Because the rays (which fall at various degrees of obliquity on the
water) are _reflected at similar angles_; but as only those which _meet
the eye of the spectator_ are visible, all the sea will appear dark but
_that one spot_.
[Illustration: 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 spectator D, but no
other spot of the water ABC.]
Q. _At night the MOON seems to be reflected from only ONE SPOT of a lake
of water, while all the REST seems DARK,--WHY is this?_
A. Because the rays (which fall at various degrees of obliquity on the
lake) _are reflected at similar angles_; but as only those which _enter
the eye of the spectator_ will be visible, all the water will appear
dark _but that one spot. (See last figure.)_
Q. _Why are MORE STARS visible from a MOUNTAIN, than from a PLAIN?_
A. As the air _absorbs and diminishes light_, the _higher we ascend_,
the _less light will be absorbed_.
Q. _Why does the SUN seem LARGER at his RISE and SET, than it does at
NOON?_
A. Because the earth is surrounded by air, which acts like a _magnifying
glass_; and when the sun is near the horizon (as its rays _pass through
more of this air_), it is more magnified.
[Illustration: Here SC represents a ray of the sun at noon, and MC a ray
of the sun near the horizon. DEG represents the air or atmosphere around
the earth.
Because EC is longer than DC, therefore the rays of the sun at M pass
through _more air_ than the rays of the sun at S, and the sun is more
magnified.]
Q. _Why does the RISING and SETTING MOON appear so much LARGER, than
after it is risen higher above our heads?_
A. Because the earth is surrounded by air, which acts _like a magnifying
glass_; and when the moon is near the horizon (as its rays pass through
more of this air) it is more magnified. _(See last figure.)_
Q. _When CANDLES are LIGHTED, we CANNOT SEE into the STREET or
road,--WHY is this?_
A. 1st--Because glass is a _reflector_, and throws the candle-light
_back into the room again_; and
2ndly--The pupil of the eye (which has become _contracted_ by the light
of the room) is _too small_ to collect rays enough from the dark street,
to enable us to _see into it_.
Q. _Why can't persons in the street SEE into a WELL-LIGHTED ROOM?_
A. Because the pupil of their eyes is _much dilated by the dark_, and
cannot collect from the window sufficient rays to enable them to _see
into the room_.
Q. _Why do we often see the FIRE REFLECTED in our parlour WINDOW in
winter time?_
A. Because glass is a _good reflector_; and the rays of the fire
(striking against the window-glass) _are reflected back into the room
again_.
Q. _Why do we often see the shadow of our CANDLES in the window, while
we are sitting in our parlour?_
A. Because the rays of the candle (striking against the glass) are
_reflected back into the room_: and the _darker_ the night, the
_clearer_ the reflection.
Q. _Why is this reflection more clear, if the external AIR be DARK?_
A. Because the reflection is not then _eclipsed_ by the brighter rays of
the sun _striking on the other side of the window_.
Q. _Why is the SHADOW of an object (thrown on the wall) LARGER and
larger, the CLOSER any object be held to the CANDLE?_
A. Because the rays of light _diverge_ (from the flame of a candle) _in
straight lines_, like lines drawn from the centre of a circle.
[Illustration: Here the arrow A held close to the candle, will cast the
shadow BF on the wall: while the same arrow held at C, would cast only
the little shadow D E.]
Q. _When we enter a long AVENUE of TREES, WHY does the avenue seem to
get NARROWER and narrower till it appears to MEET?_
A. Because the _further the trees are off_, the more _acute will be the
angle_ that any two will make with our eye.
[Illustration: Here the width between the trees A and B will seem to be
as great as the line AB: But the width between the trees C and D will
seem to be no more than EF.]
Q. _In a long straight STREET, WHY do the houses seem to APPROACH NEARER
and nearer as they are more DISTANT?_
A. Because the more _distant the houses_ are, the more _acute will be
the angle_ which any 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 A B:
And if C and D were two houses at the bottom of the street, the street
at the bottom would seem to be no wider than E F.
Q. _In an AVENUE of TREES, WHY do they seem to be SMALLER as their
distance increases?_
A. Because the _further the trees are off_, the more _acute will be the
angle_ made by their perpendicular height with our eye.
[Illustration: Here the first tree A B will appear the height of the
line A B; but the last tree C D will appear only as high as the line E
F.]
Q. _In a long straight STREET, WHY 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 will be the
angle_ made by its perpendicular height with our eye.
Thus in the last figure--
If A B be a house at the top of the street, its perpendicular height
will be that of the line A B.
If C D be a house at the bottom of the street, its perpendicular height
will appear to be that of E F.
Q. _Why does a man on the TOP of a MOUNTAIN or church spire seem to be
no BIGGER than a CROW?_
A. Because the angle made by the _perpendicular height of the man_ (at
that distance) _with our eye_, is no bigger than the perpendicular
height of a _crow close by_.
[Illustration: 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 BIGGER than the STARS, though
in fact it is a great deal SMALLER?_
A. Because the moon is _very much nearer to us_ than any of the stars.
[Illustration: Let AB represent a fixed star, and CD the moon.
AB, though much the larger body, will appear no bigger than EF; whereas
the moon (CD) will appear as big 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 went 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.
Had it begun, therefore, when Adam was created, it would be no further
on its journey than a coach (which has to go from the bottom of Cornwall
to the top of Scotland) after it has past about three-quarters of a
mile.]
Q. _Why does the MOON (which is a sphere) APPEAR to be a FLAT surface?_
A. It is _so far off_, that we cannot distinguish any difference between
the _length of the rays_ which issue from the _edge_, and those which
issue from the _centre_.
[Illustration: The rays AD and CD appear to be no longer than the ray
BD; but if all the rays seem of the same length, the 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. _Why do the SUN and STARS (which are spheres) appear to be FLAT
surfaces?_
A. Because they are such an _immense way off_, that we can discern _no
difference of length_ between the rays which issue from the _edge_, and
those which issue from the _centre_ of these bodies.
The rays AD and CD appear no longer than BD; and as B appears to be no
nearer than A or C, therefore ABC must all seem equally distant; and ABC
will seem a flat or straight line. (See last figure.)
Q. _Why does DISTANCE make an object INVISIBLE?_
A. Because the angle (made by the _perpendicular height_ of the distant
object _with our eye_) is so very _acute_, that _one_ line of the angle
_merges in the other_.
[Illustration: 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, till after
the point B is past; when the tree will appear like a very little
speck.]
Q. _Why do TELESCOPES enable us to SEE objects INVISIBLE to the naked
eye?_
A. Because they _concentrate several rays_ within the tube of the
telescope, and _bend them upon the mirror or lens_, which acts as a
_magnifying glass_.
Q. _When a SHIP (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 round_, and the _curve_ of the sea _hides the
hull_ from our eyes, after the tall _masts_ have become visible.
[Illustration: Here only that part of the ship above the line AC 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. The _bending of a ray of light_, as it passes from one medium to
another.
Q. _How is a ray of light BENT, as it passes from 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 _from_ the perpendicular.
[Illustration: Suppose DE to be a perpendicular line.
If AB (a ray of light,) enters the water, it will be bent _towards_ the
perpendicular to C.
If (on the other hand) CB (a ray of light) emerges _from_ the water, it
would be bent _away from_ the perpendicular towards A.]
Q. _Why does a SPOON (in a glass of water) always appear BENT?_
A. Because as the light of the spoon _emerges from the water_, it is
_refracted_.
And the spoon looks like ABC. (See the last figure.)
Q. _Why does a river always appear more shallow than it really is?_
A. Because the light of the bottom of the river is REFRACTED as it
emerges out of the water: and (as a stick is not so long when it is
_bent_, as it is when it is _straight_) so the river seems less deep
than it really is.
Q. _How much deeper is a river than it seems to be?_
A. One-third. If, therefore, a river seems only 4 feet deep, it is
really 6 feet deep.
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 6 feet deep, and so on.
Q. _Why do fishes always seem to be nearer the surface of a river than
they really are?_
A. Because the rays of light from the fish are _refracted_ as they
emerge from the eye: and (as a bent stick is not so far from end to end
as a straight one) so the fishes appear nearer our eye than they really
are.
Q. _Why are some persons NEAR-SIGHTED?_
A. Because the COR´NEA of their eye is so _prominent_, that the image of
distant objects is reflected _before it reaches the_ RET'INA; and,
therefore, is not distinctly seen.
N.B. The cor´nea shields the CRYSTALLINE LENS, and is more or less
convex according to the lens which it covers.
Q. _What is meant by the "COR'NEA of the EYE?"_
A. All the _outside_ of the visible part of the _eye-ball_.
[Illustration: The curve A B C is called the COR'NEA.
If this curve be too prominent (or convex), the eye is near-sighted.
If too flat (or concave), the eye is far-sighted.]
Q. _What is meant by the "RET'INA of the EYE?"_
A. The net-work which lines the _back of the eye_, is so called.
[Illustration: The net-work ABC is called the ret'ina, and the
projecting part DEF is called the cor'nea.]
Q. _What 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. _What is meant by "DOUBLE CONCAVE GLASSES?"_
A. Glasses hollowed in _on both sides_.
[Illustration: The figure A is double concave, or concave on both
sides.]
Q. _What is meant by the "IMAGE of objects being reflected BEFORE it
reaches the RET'INA?"_
A. If the cor'nea be _too convex_, the image of a distant object is
reflected (on the vitreous humours of the eye) _before it reaches the
ret'ina_.
[Illustration: Thus the image is reflected at DE, instead of on ABC (the
ret'ina).]
Q. _What is the use of DOUBLE CONCAVE SPECTACLE glasses?_
A. Near-sighted spectacles _cast the reflection further back;_ and the
image (being _thrown upon the ret'ina_) becomes visible.
Q. _Why are OLD people FAR-SIGHTED?_
A. Because the humours of their eyes _are dried up by age_, and the
COR'NEA _sinks in_, or becomes flattened.
Q. _Why does the FLATTENING of the COR'NEA prevent persons seeing
objects which are NEAR?_
A. As the cor'nea _is too flat_, the image of any near object is formed
_behind the RET'INA of the eye_, and is not seen at all.
[Illustration: The reflection is made at DE, instead of at ABC (the
retina).]
Q. _What sort of GLASSES do OLD people WEAR?_
A. As their cor'nea is _not sufficiently convex_, they must 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.
[Illustration: The figure A is double convex, or convex on both sides.]
Q. _What is the USE of DOUBLE CONVEX spectacle-glasses?_
A. As the image of near objects is reflected _behind the RET'INA_, these
double convex glasses _shorten the focus of the eye_, and bring the
image _into the eye_ (upon the ret'ina).
Q. _Why do NEAR-SIGHTED persons bring objects CLOSE to the eye, in order
to SEE THEM?_
A. As the distance between the _front and back of their eye is too
great_, distant objects are reflected _before they reach the ret'ina_;
therefore, near-sighted persons bring the objects _closer_, in order
that the reflection _may be cast further back_, (to reach the ret'ina).
Q. _Why do OLD people HOLD objects FURTHER OFF, in order to see them
better?_
A. As the distance between the _front and back of their eye is not great
enough_, the reflection of near objects is thrown _beyond the ret'ina_;
therefore, they hold objects _a long way off_, in order to bring their
images _forward_ (so as to cast it on the ret'ina).
Q. _Why are HAWKS 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.
This muscle is called the "marsupium."
Q. _Why can HAWKS not only see such a long way off, but also objects
within half-an-inch of their eye?_
A. Because their eyes are furnished with a broad circular rim which
_confines the action of this muscle_, and throws the _cor'nea forward_.
Q. _Into how many PARTS may a RAY of LIGHT be DIVIDED?_
A. Into three parts: BLUE, YELLOW, and RED.
N.B. These 3 colours, by combination, make seven. 1.--RED. 2.--Red and
yellow form ORANGE. 3.--YELLOW. 4.--Yellow and blue make GREEN.
5.--BLUE. 6 and 7.--Shades of blue called INDIGO and VIOLET.
Q. _How is it KNOWN, that a ray of light consists of several different
colours?_
A. Because, if a ray of light be cast upon a triangular piece of glass
(called a prism), it will be distinctly divided into seven colours:
1.--Red; 2.--Orange; 3.--Yellow; 4.--Green; 5.--Blue; 6.--Indigo; and
7.--Violet.
Q. _Why does a PRISM DIVIDE a ray of light into VARIOUS COLOURS?_
A. Because all these colours have _different refractive powers_. Red is
refracted _least_, and blue the _most_; therefore, the _blue_ colour of
the ray will be bent to the _top_ of the prism, and the _red_ will
remain at the _bottom_.
[Illustration: Here the ray AB received on a prism, would 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.
[Illustration: Let A, B, and C be three drops of rain; SA, SB, and SC
three rays of the sun. SA is divided into the 3 colours; the blue and
yellow are bent _above_ the eye D, and the _red_ enters it.
The ray SB is divided into the three colours; the blue is bent _above_
the eye, and the red falls _below_ the eye D; but the _yellow_ enters
it.
The ray SC is also divided into the three colours. The blue (which is
bent most) enters the eye; and the other two fall below it. Thus the eye
sees the blue of C, and 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, &c.; and thus
it sees a rainbow.]
Q. _Does EVERY person see the SAME colours from the SAME DROPS?_
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, yellow; 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. _Why are there often TWO RAINBOWS at one and the 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 _from the bottom_.
In the _other_ rainbow, we see the rays of the sun _entering the
rain-drops at the bottom_, and reflected to the top, whence they reach
the eye.
[Illustration: Here the ray SA strikes the drop at A,--is refracted or
bent to B,--is then reflected to C, where it is refracted again, and
reaches the eye of the spectator.]
[Illustration: Here the ray SB 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. _Why are the COLOURS of the SECOND bow all REVERSED?_
A. Because in _one_ bow we see the rays which enter at the _top_ of the
raindrops, _refracted from the bottom_:
But in the _other_ bow we see the rays which enter at the _bottom_ of
the raindrops (after two reflections), _refracted from the top_.
[Illustration: Here A, B, C, represent three drops of rain in the
PRIMARY (or inner) RAINBOW.
The _least_ refracted line is RED, and BLUE the _most_.
So the RED (or _least_ refracted rays) of all the drops in the position
of A,--the YELLOW of those in the position of B,--and the BLUE (or the
_most_ refracted rays) of the lowest drops, all meet the eye D, and form
a rainbow to the spectator.
The reason why the primary bow exhibits the stronger colours is
this--because the colours are seen after _one_ reflection and _two_
refractions; but the colours of the secondary (or upper) rainbow undergo
_two_ reflections and _three_ refractions.]
[Illustration: Here also the _least_ refracted ray is RED, and the
_most_ refracted BLUE (as in the former case); but the position of each
is reversed.]
Q. _Why does a SOAP BUBBLE exhibit such VARIETY of COLOURS?_
A. The changing colour of the bubble depends upon the changing
_thickness of the film_ through which the ray passes.
Q. _How does the THICKNESS of the FILM affect the COLOUR of the soap
bubble?_
A. Because different _degrees of thickness_ produce different _angles of
refraction_, and, therefore, different colours reach the eye.
Q. _Why is the SOAP BUBBLE so constantly CHANGING its THICKNESS?_
A. As the bubble is _suspended_, the water keeps _running down from the
top_ to the bottom of the bubble, till the crown becomes so _thin_ as to
burst.
Q. _Why are the late EVENING CLOUDS RED?_
A. Because RED rays (being the _least refrangible_) are the _last to
disappear_.
[Illustration: Here it will be seen that the red ray PA, being reflected
on the horizon at A, will be visible to us; but the YELLOW and BLUE rays
will be hidden by the curve of the earth.]
Q. _Why are the early MORNING clouds RED?_
A. Because RED rays (being the _least refrangible_) are the _first to
appear_.
_See last figure._--It is evident that PA (the red rays) will be
reflected on the horizon before either the yellow or blue ones.
Q. _What becomes of the BLUE and YELLOW rays?_
A. They are refracted _below the horizon_, and are soon made invisible
by the _curve of the earth_. (_See last figure._)
Q. _Why are the EDGES of CLOUDS more LUMINOUS than their CENTRES?_
A. Because the _body of vapour is thinnest_ at the edges of the clouds.
Q. _What 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 towards the earth_, and produce a
little light called twilight.
_See figure on p. 399._--Here the rays of PA will give _some_ light.
Q. _Why is a ray of LIGHT composed of VARIOUS COLOURS?_
A. If solar light were of _one colour only_, all objects would appear of
_that one colour_ (or else black.)
Q. _Why are some things of ONE COLOUR, and some of ANOTHER?_
A. As every ray of light is composed of all the colours of the rainbow,
_some_ things reflect _one of these colours_, and some _another_.
Q. _Why do some things reflect ONE COLOUR, and some ANOTHER?_
A. Because the _surface_ of things is so _differently constructed_, both
physically and chemically; and, therefore, _some_ things reflect _one_
ray; some _two rays_; some _all_ the rays; and some _none_.
Q. _What mainly determines the COLOUR of any object?_
A. The fluid or gas either _in_ the body, or on its _surface_.
N. B. Nitrogen gives green,--Oxygen gives red,--Hydrogen gives blue
colours.
Q. _Why does DYING a silk, &c. CHANGE its COLOUR?_
A. Because the materials used in dyeing _alter the chemical
construction_ of the substance dyed.
Q. _Why is a ROSE RED?_
A. Because the surface of a rose _absorbs the blue and yellow_ rays of
light, and _reflects_ only the _red_ ones.
Q. _Why does a rose absorb the yellow and blue rays, and reflect the
RED?_
A. Because the action of the sun's rays on the oxygen (accumulated in
the petals) produces an _acid_ which turns them _red_.
The leaves which compose a flower, are called PETALS.
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. _Why do violets absorb the red and yellow rays, and reflect the
BLUE?_
A. Because the petals of the violet contain an _alkali_, which gives
them a _purple tinge_.
Q. _Why is a PRIMROSE YELLOW?_
A. Because the surface of the primrose _absorbs the blue and red_ rays
of solar light, and _reflects_ the _yellow_ ones.
All plants which have much alkali in their ash, have blue or yellow
flowers.
Those which have acid in their ash, have orange, pink, or red flowers.
N. B. Anti-acids (like soda) are called ALKALIS.
Q. _Why are some things BLACK?_
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, and stifle their reflection.
Q. _Why is SNOW WHITE?_
A. Snow consists of a vast number of crystals (or small prisms), which
separate the rays into their elemental colours; but as these crystals
are very numerous, the colours _unite again_ before they meet the eye,
and _appear white_.
N. B. The combination of _all_ colours makes WHITE.
Q. _Why is SUGAR WHITE?_
A. Sugar consists of a vast number of small crystals, which separate the
rays into their elemental colours; but as these crystals are very
numerous, the colours _unite again_ before they meet the eye, and appear
_white_.
Q. _Why is SALT WHITE?_
A. Salt consists of a vast number of small crystals, which reflect the
various rays of light from different points of the salt; and as these
colours _unite_ before they meet the eye, the salt appears to be
_white_.
N. B. The combination of _all_ colours makes WHITE.
Q. _Why are the LEAVES of plants GREEN?_
A. Because the _carbon_ of the leaves is a _bluish olive_, and the _sap_
and _tissue of the cells_, YELLOW; when, therefore, the _yellow sap_
flows into the _blue carbon_, it produces a _green leaf_.
Q. _Why are leaves a LIGHT green in SPRING?_
A. Because the young leaves of spring have _more sap_ than _carbon_;
and, therefore, the _yellow_ of the green prevails.
Q. _Why are leaves a YELLOWISH BROWN in AUTUMN?_
A. Because the _carbon_ of the leaves is _dying away_, and the yellow
tinge of the _tissue_ and _falling sap_ prevails over the blue.
Q. _Why are plants a PALE YELLOW when kept in the DARK?_
A. Solar light is essential for the production of _carbon_; and as
plants kept in the dark _lose their carbon_, they lose the _blue colour_
which should convert their yellow sap to _green_.
Q. _Why are POTATOES YELLOW?_
A. Potatoes are grown _underground_, and, therefore, contain very little
_carbon_ (or blue colour); hence the _yellow sap_ of the potato is not
converted to green by carbon.
Q. _Why are potatoes (which grow EXPOSED to the air and light) GREEN?_
A. Because the sun-light _increases their carbon_; which (mingling with
the yellow sap) turns the potato _green_.
Q. _Why is it DANGEROUS to SLEEP in a room which contains LIVING
PLANTS?_
A. Because they _exhale carbon in the dark_ in the form of CARBONIC ACID
GAS, which is destructive to animal life.
Q. _Why are SOME things (like glass) TRANSPARENT?_
A. In transparent bodies (like glass) all the rays of light _emerge on
the opposite side_.
Q. _Why are SOME things SHINING and splendid?_
A. Those objects which _reflect the most rays_ are the most _splendid_;
and those which _absorb_ them most, are _dull_.
Q. _Why are DESERTS so DAZZLING in summer time?_
A. Because each separate grain of sand _reflects the rays of the sun_
like a mirror.
Q. _If you move a stick (burnt at one end) ROUND pretty briskly, it
seems to make a CIRCLE OF FIRE,--WHY is this?_
A. Because 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 image has faded_ from the eye, therefore, 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 seems to be
seated on the horse,--WHY is this?_
A. Because the image of the horse _remains upon the eye_ till the _man_
appears.
The Thaumatrope is constructed on this principle.
Q. _Why do the STARS TWINKLE?_
A. Fixed stars are _so far off_, that their rays of light do not strike
upon the eye _in a continuous flow_, but at _intervals_: when their rays
_reach the eye_, the star becomes _visible_, and then is obscured _till
the next batch of rays arrive_; and this _perpetually_ occurring, makes
a kind of _twinkling_.
Q. _If we look at a RED-hot FIRE for a few minutes, WHY does every thing
seem TINGED with a BLUISH GREEN colour?_
A. Because bluish green is the "ACCIDENTAL COLOUR" of red: and if we fix
our eye upon _any colour whatsoever_, when we turn aside, we see every
object tinged with _its accidental colour_.
Q. _If we wear BLUE GLASSES, (when we take them off,) every thing
appears tinged with ORANGE,--WHY is this?_
A. Because _orange_ is the "_accidental colour_" of blue: and if we look
through _blue glasses_, we shall see its "_accidental colour_," when we
lay our glasses aside.
Q. _If we look at the SUN for a few moments, every thing seems tinged
with a VIOLET colour,--WHY is this?_
A. Because _violet_ is the "accidental colour" of _yellow_ light; and as
the sun is _yellow_, we shall see its "accidental colour" _blue_, when
we turn from gazing at it.
Q. _Does not the DARK SHADOW (which seems to hang over every thing after
we turn from looking at the sun) arise from our eyes being DAZZLED?_
A. Partly so: the pupil of the eye is _very much contracted_ by the
brilliant light of the sun, and does not adjust itself immediately to
the feebler light of terrestrial objects; but, independent of this, the
"ACCIDENTAL COLOUR" of the sun being _dark violet_, would tend to throw
a shadow upon all things. (_See p. 366._)
Q. _Why is BLACK glass for spectacles the BEST for wear?_
A. Because _white_ is the accidental colour of _black_; and if we wear
_black glasses_, every thing will appear _in white light_, when we take
them off.
Q. _Why does every thing seem shadowed with a BLACK MIST, when we take
off our common SPECTACLES?_
A. Because the glasses are _white_, and black being its "accidental
colour," every thing appears in a _black shade_, when we lay our glasses
down.
The accidental colour of red is bluish green.
" " " of orange " blue.
" " " of violet " yellow.
" " " of black " white.
And the converse of this is true:--
The accidental colour of bluish green is red.
" " " of blue " orange.
" " " of yellow " violet.
" " " of white " black.
(The law of an accidental colour is this--The accidental colour 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 colour, the
other leg will hit upon its accidental colour.)
N. B. The spectrum means the seven colours--Red, orange, yellow, green,
blue, indigo, and violet, divided into seven equal bands, and placed
side by side in the order just mentioned.
CHAPTER XXVIII.
SOUND.
Q. _What is SOUND?_
A. The vibration of some sonorous substance produces motion in the air
called SOUND WAVES, which strike upon the _drum of the ear_, and give
the sensation of sound.
Q. _What are MUSICAL SOUNDS?_
A. Regular and uniform successions of vibrations, which are always
pleasing to the ear.
Q. _How FAST does SOUND TRAVEL?_
A. About 13 miles in a minute, or 1142 feet in a second of time.
Q. _How fast does LIGHT TRAVEL?_
A. Light would go 8 times round the whole earth, while sound is going
its 13 miles.
Q. _Why are SOME things SONOROUS, and others NOT?_
A. The sonorous quality of any substance depends upon its _hardness and
elasticity_.
Q. _Why are COPPER and IRON 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 bell-metal, there should be 1 lb. of tin, and 4 lbs. of copper.
Q. _Why is this mixture of tin and copper used for BELL-METAL?_
A. Because it is much _harder_ and more _elastic_ than either of the
pure metals.
Q. _Why is the SOUND of a bell STOPPED by TOUCHING the bell with our
finger?_
A. The weight of the 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. 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. _Why does a FIDDLE-STRING give a musical sound?_
A. The bow drawn across the string _causes it to vibrate_, and this
vibration of the string _sets in motion the sound-waves of the air_, and
produces musical notes.
Q. _Why does a DRUM sound?_
A. The parchment head of the drum _vibrates_ from the blow of the
drum-stick, and sets in motion the sound-waves of the air.
Q. _Why 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, &c. produce musical sounds?_
A. The breath of the performer causes the _air in the flute to vibrate_,
and sets in motion the sound-waves of the air.
Q. _Why do PIANO-FORTES produce musical sounds?_
A. The _keys of the piano_ (being struck with the finger) lift up a
little hammer which _knocks against a string_; and the vibration thus
produced, sets in motion the sound-waves of the air.
Q. _Why are SOME notes BASS and some TREBLE?_
A. _Slow_ vibrations produce _bass or deep sounds_; whereas, _quick_
vibrations produce _shrill or treble sounds_.
Q. _Why is an instrument FLAT when the STRINGS are UNSTRUNG?_
A. Because the vibrations are _too slow_; in consequence of which, the
sounds produced are not _shrill_ or _sharp_ enough.
Q. _Why can persons living a mile or two from_
_a town HEAR the BELLS of the town-church SOME TIMES, and not at
OTHERS?_
A. Fogs, rain, and snow, obstruct the passage of sound; but when the air
is _cold and clear_, sound is propagated more easily.
Q. _Why can we NOT hear sounds (as distant church bells) in RAINY
weather, so well as in FINE weather?_
A. Because the falling rain _interferes with the undulations of the
sound-waves_, and breaks them up.
Q. _Why can we not hear sounds (as distant church bells) in SNOWY
weather, so well as in FINE weather?_
A. Because the falling snow _interferes with the undulations of the
sound-waves_, and stops their progress.
Q. _Why can we HEAR distant clocks MOST distinctly in CLEAR COLD
weather?_
A. Because the air is most _uniform_ then: there are not _two currents
of air_ (one up and one down) to interrupt the sound-waves.
Q. _Why can persons hear the VOICES of men in conversation for a MILE
distant, near the POLES, in winter time?_
A. Because the air is very _cold and very clear_; in consequence of
which, there are not _two currents of air_ (one up and one down) to
interrupt the sound-waves.
Captain Ross heard the voices of his men in conversation, a mile and a
half from the spot where they stood.
Q. _Why are not SOUNDS (such as distant church bells) heard so
distinctly on a HOT DAY as in FROSTY weather?_
A. Because there are _two currents of air_; the current of _hot_ air
_ascending from the earth_, and the current of _colder_ air _falling
towards_ the earth; and these two currents _break up the sound-waves_.
Q. _Why can we not hear SOUNDS (such as distant clocks) so distinctly in
a thick MIST or HAZE, as in a CLEAR night?_
A. Because the mist _diminishes the velocity_ of the sound-waves, and
(by overburdening them with vapour) _limits their length_.
Q. _Why do we hear SOUNDS better by NIGHT than by DAY?_
A. 1st--Night air is _more uniform_, because the ascending currents of
air (raised by the action of the sun's rays) _cease_ as the evening
advances; and
2ndly--Night is more _still_ from the suspension of business, and the
cessation of the hum of men.
Q. _How should PARTITION WALLS be made to PREVENT the voices in
adjoining rooms from being HEARD?_
A. The space between the laths (or canvass) should be filled with
_shavings or saw-dust_; and then no sound would ever pass from one room
to another.
Q. _Why would SHAVINGS or saw-dust PREVENT the transmission of sound
from room to room?_
A. Because there would be _several different media_ for the sound to
pass through: 1st--the air;
2ndly--the laths and paper;
3rdly--the saw-dust or shavings;
4thly--the air again: and every _variety_ diminishes the _strength of
the sound-waves_.
Q. _Why can DEAF people hear through an EAR TRUMPET?_
A. The ear trumpet restrains _the spread of the voice_, and limits the
_diameter of the sound-waves_; in consequence of which, their
_strength_ is increased.
Q. _Why are MOUNTAINS so NOISELESS and quiet?_
A. Because the air of mountains is _very rarefied_; and as the air
becomes _rarefied_, sound becomes less _intense_.
Q. _How do you know that the RARETY of air DIMINISHES the intensity 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 quite
_inaudible_.
Q. _What is the cause of ECHO?_
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 p. 370._)
Q. _What places are most FAMOUS for ECHOES?_
A. Caverns, grottoes, and ruined abbeys; the areas of antique halls; the
windings of long passages; the aisles of cathedral churches; mountains,
and ice-bergs.
Q. _Why are caverns, grottoes, and ruined abbeys FAMOUS for ECHOES?_
A. 1st--Because the sound-waves cannot pass _beyond_ the cavern or
grotto, and _must flow back_:
2ndly--The _return waves_ (being entangled by the cavern) are _detained_
for a short time, and come _deliberately_ to the ear.
Q. _Why are antique halls, winding passages, and cathedral aisles FAMOUS
for ECHOES?_
A. Because the sound-waves _cannot flow freely forward_, but strike
against the winding walls perpetually, and are beaten _back_.
Q. _Why are MOUNTAINS and ice-bergs FAMOUS for ECHOES?_
A. Because they present a _barrier_ to the sound-waves _which they
cannot pass_; and are sufficiently elastic to _throw them 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 _blended
with the original sound_, and produce but _one impression_ on the ear.
Sound travels 13 miles in a minute.
Q. _Why do very LARGE buildings (as cathedrals), often REVERBERATE the
voice of the speaker?_
A. Because the walls are _so far off from the speaker_, that the echo
does not _get back in time_ to blend with the original sound; and,
therefore, _each_ is heard separately.
Q. _Why do SOME echoes repeat only ONE syllable?_
A. The _further_ the echoing body is _distant_, the _more sound_ it will
_reflect_. If, therefore, the echoing body be _near_, it will repeat but
one syllable.
Q. _Why does an ECHO sometimes repeat TWO or more syllables?_
A. Because the echoing body is _far off_; and, therefore, there is time
for one reflection _to pass away_ before _another_ reaches the ear.
Q. _Why do WINDOWS RATTLE when CARTS pass by a house?_
A. 1st--Glass is _sonorous_; and the air communicates its vibrations to
the glass, which echoes the same sound: and
2ndly--The _window-frame is shaken_ by the sound-waves _impinging
against the window_, and contributes to the noise.
CHAPTER XXIX.
MISCELLANEOUS.
Q. _Why do the BUBBLES in a CUP OF TEA range round the SIDES of the
CUP?_
A. Because the cup _attracts them_.
Q. _Why do all the LITTLE BUBBLES tend towards the LARGE ones?_
A. Because the large bubbles (being the superior masses) _attract them_.
Q. _Why do the BUBBLES of a CUP OF TEA FOLLOW a TEA-SPOON?_
A. Because the tea-spoon _attracts them_.
Q. _Why are the SIDES of a pond covered with LEAVES, while the MIDDLE of
the pond is quite CLEAR?_
A. Because the shore _attracts_ the leaves to itself.
Q. _Why do all fruits, &c. (when severed from the tree) FALL to the
EARTH?_
A. Because the earth _attracts them_.
Q. _Why do persons (who water PLANTS) very_
_often pour the water into the SAUCER, and not OVER the PLANTS?_
A. Because the water in the saucer is _supped up_ by the mould (through
the hole at the bottom of the flower-pot), and is transferred to the
stem and leaves of the plant by CAPILLARY ATTRACTION, (_See p. 84_).
Q. _Why is vegetation on the MARGIN of a RIVER more LUXURIANT than in an
open FIELD?_
A. Because the porous earth on the bank _sups up water_ to the roots of
the plants by CAPILLARY ATTRACTION.
Q. _Why is a LUMP of SUGAR (left at the bottom of a cup) so LONG in
MELTING?_
A. Because _as it melts_, it makes the tea above it _heavier_; and (so
long as it remains at the bottom) is surrounded by tea fully _saturated_
with sugar; in consequence of which, the _same_ portions of liquid will
hold _no more sugar in solution_.
Q. _Why does the LUMP of SUGAR MELT more QUICKLY when STIRRED ABOUT?_
A. Because _fresh portions of unsaturated tea_ keep coming 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 RAPIDLY?_
A. Because as the tea becomes _sweetened_, it _descends to the bottom of
the cup_ by its own gravity; and _fresh_ portions of unsweetened tea are
brought constantly into contact with the sugar, till the lump is
entirely dissolved.
Q. _How can a SICK ROOM be kept FREE from unhealthy EFFLUVIA?_
A. Vinegar boiled with myrrh, or camphor, sprinkled in a sick room, will
_entirely correct putridity_.
Q. _Why does LIME destroy the offensive smells of BINS, SEWERS, &c.?_
A. Because it combines with the _carbonic acid_ of these places, and
converts it into CARBONATE OF LIME, which is entirely _free from smell_.
Q. _Why does CHLORIDE of LIME fumigate a sick room?_
A. Because the chlorine absorbs the _hydrogen of the stale air_; and by
this means removes both the _offensive smell_ and the _infection_ of a
sick room.
Q. _How can the TAINT of MEAT be removed?_
A. Either by washing with PYROLIGNEOUS ACID,--covering it for a few
hours with common CHARCOAL,--or by putting a _few lumps of charcoal_
into the _water in which it is boiled_.
Q. _Why do these things DESTROY the TAINT of meat?_
A. Because they _combine_ with the _putrescent particles_, and
neutralize their offensive taste and smell.
Q. _Why should BED-ROOMS, COTTAGES, HOSPITALS, and STABLES, be washed
occasionally with LIME-WHITE?_
A. Because the lime _is very caustic_, and removes all organic matters
adhering to the walls.
Q. _How can MOULDINESS be prevented?_
A. The perfume of _any essential oil_ will prevent mouldiness from ink,
paste, preserves, &c.
Alum, salt of amber, borax, nitre, salt, camphor, charcoal, and
pyroligneous acid, are all excellent antiseptics.
Salt, corrosive sublimates, copperas, and alum, all arrest the decay of
timber. (_See p. 426._)
Q. _Why will strong SOUCHONG TEA POISON FLIES?_
A. Because it produces _prussic acid_, which destroys their _nervous
system_.
Q. _Why is strong GREEN TEA UNWHOLESOME?_
A. Because it contains _prussic acid_, which destroys the _nervous
system_.
Q. _Why is a DEAD man TALLER than a living man?_
A. Because at death the CARTILAGES are _relaxed_. So, also, after a
night's rest, a man is _taller_ than when he went to bed.
Q. _What is SLEEP?_
A. Sleep is the _rest of the brain_ and _nervous system_.
Q. _Why can we not SEE, when we are asleep with our EYES OPEN?_
A. Because the "RET´INA of the eye" is _inactive_ and at rest.
Q. _Why can we not HEAR in sleep?_
A. Because the drum or "TYMPANUM of the ear" is placid and at rest.
Q. _Why can we not TASTE when we are asleep?_
A. Because the nerves _at the end of the tongue_ (called papillæ) are
inactive and at rest.
Q. _Why can we not FEEL when we are asleep?_
A. Because the _ends of the nerves_ (called papillæ), 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" (or _posterior_ part of the brain) is
inactive and at rest.
Q. _Why have DREAMERS no power of JUDGMENT or REASON?_
A. Because the "CEREBRUM" (or _front_ of the brain) is inactive and at
rest.
Q. _Why are DREAMS such FOOLISH and INCONSISTENT things?_
A. Because the "PINEAL GLAND" is acting _without the brain_; and the
_faculty of thinking_ exists in the "PINEAL GLAND," but the _faculty of
judgment_ in the "CEREBRUM of the brain."
The cerebrum of the brain occupies the top and front of the skull. The
PINEAL GLAND is a small conical gland (about the size of a pea) _in the
brain_.
Q. _Why do some persons LOSE all POWER of SENSATION?_
A. Because the "CEREBRUM" (or _front_ of their brain) _has been
injured_.
Q. _Why are many persons IDIOTS?_
A. Because the "CEREBELLUM of the brain" _has been removed_ by some
accident, or _injured by some disease_.
The cerebellum is all the posterior part of the brain.
Q. _Why does a person FEEL when he is TOUCHED?_
A. The ends of certain nerves (called PAPILLÆ) situated in the skin
_erect themselves_ when touched, and produce a nervous sensation called
FEELING.
Q. _Why are persons able to TASTE DIFFERENT FLAVOURS?_
A. Because the "PAPILLÆ" of the tongue and palate _erect themselves_
when food touches them, and produce a nervous sensation called TASTE.
Q. _Why do very OLD people LOSE the power of VOLITION, SENSATION, and
THOUGHT?_
A. Because their _brain ossifies_; and as the "_cerebrum_" (or _front_
of the brain) goes, they lose the power of _sensation and reason_; and
as the "_cerebellum_" (or _posterior_ part of the brain) goes, they lose
the power of _volition_.
Q. _Why are OLD people UNABLE to WALK?_
A. Because their _muscles become rigid_.
GLOSSARY.
ACETIC ACID, commonly called Distilled Vinegar.
CITRIC " " Juice of Lemons.
NITRIC " " Aqua Fortis.
OXALIC " " Salt of Lemons.
SULPHURIC " " Oil of Vitriol.
SULPHATE OF LIME " Plaster of Paris.
" MAGNESIA " Epsom Salts.
" SODA " Glauber Salts.
" ZINC " White Vitriol.
NITRATE OF SILVER " Lunar Caustic.
ACETATE OF COPPER " Verdigris.
MURIATE OF SODA " Table Salt.
TARTRATE OF POTASH " Tartar Emetic.
CARBONATE OF AMMONIA " Smelling Salts.
" LIME " Chalk, Marble, &c.
SUPER-ACETATE OF LEAD " Sugar of Lead.
OXIDE OF LEAD " Goulard.
SUBLIMATES are chemical preparations, the basis of
which is quicksilver. In CORROSIVE SUBLIMATES, the
quicksilver is _extinguished_, either by vitriol, potter's clay, or
some other ingredient.
SUBLIMATION 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 thus:--Take 2 parts of quicksilver, 3 flower of
brimstone, 8 sal ammoniac; and (having ground them)
put them with the quicksilver into a glass retort, 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.
INDEX.
ABSORBERS, best, 192
not conductors, 185
not reflectors, 192
radiators, 197
ABSORPTION of HEAT, 184
not conduction, 184
of light, 364
ACCIDENTAL COLORS, 407, 408
Acetate of lead, 426
Acetic acid, 426
Acid of drinks, 269
of fermentation, 269
Activity affected by cold, 91
" by heat, 93
Aerated water, 267
Aeronauts feel pain, 254
Age affects the sensation, thought, judgment, 425
power of walking, 425
AIR, 240
always in motion, 293
bad conductor, 13, 177, 178
bad radiator, 219, 237
cold, 177
colder than blood, 181
composed of two gases, 27, 240
cooled by convection, 220
" by rain, 159
cools hot iron, 246
density diminished by rain, 337
descends when cold, 289
double current in a room, 290
dries linen, 160
elements of, 33
expanded by heat, 103
full of smells, 152
gets fire up, 50
healthful, 252
heated, 219, 245, 246, 289
" not by sun, 290
in a room, 252
inflammable, _see hydrogen_
in summer, 313
of cities unhealthy, 243, 253
of the country healthy, 243, 252
on land colder than on water, 224
on land cold at night, 230
preserved normal, 244
purified by lightning, 27
rusts iron, 257
still before a tempest, 146
strong, 108
varies in temperature, 335
Aisles famous for echoes, 417
Alcohol, 109, 270, 271
ALE, 109
bottled, 268
froth of, 109
froth increased by heat, 268
Alkali, 45
Anenometer, 314
Anglers hate a magpie, 153
Angle of incidence, 370
of reflection, 370
Animal heat, 83, 85, 243, 277
Animals and vegetables co-dependent, 244
Ants love honey-dew, 221
Appetite, 89, 90, 91
(_See hunger._)
Apples full of air, 105
roasted, 105
soft, 106
April showers, 307
Aqua fortis, 426
Argand lamps, 83
Arnott's stoves smell of sulphur, 56
smoke, 69
Ascent in balloons painful, 145
Ashes soften water, 345
Asses bray in wet weather, 148
Aurora borealis, 142, 285
coloured, 143
white, 142
a prognostic, 143
Avenues, 380
Azote, _see nitrogen_
Bales catch fire spontaneously, 57
Balloons, 146
inflated, 109
rise, 110
Balls of fire, 6
Banisters wet, 216
Barley malted, 270
BAROMETER, 317
affected by cold, 328
" frost, 329
" heat, 328
" thaw, 329
" wind, 327
rules for its rise and fall, 330
sudden change in, 330
use of, 319
varies most in winter, 327
" least in summer, 327
when highest, 328
" lowest, 328
Barren land collects no dew, 209
Bass notes in music, 412
Bass preserves flowers from frost, 206
Bathing, danger of, 387
with ether for inflammation, 157
Beakers broken by hot water, 126
Beasts covered with hair, 176
Beds damp, 157
BEER, fermentation of, 269
flat, 273
froth increased by bottling, 268
froth increased by heat, 268
raisins and raw meat improve it, 273
stale, 275
soured by lightning, 27
not _old_ beer, 27
spoiled, if the vent-peg be left out, 273
yeast added to make it work, 271
Beer-vats dangerous, 265
Bells heard at a distance, 412
cracked, sound harsh, 411
silenced by a touch, 411
Bell-metal, 410
Bellows, 51
Bins purified, 266
Birds covered with feathers, 176
BLACK, 402
cloth warm, 186
eyes, 191
glass for spectacles, 408
hat turns red at the sea-side, 344
Hole of Calcutta, 250
kid gloves, 188
lead, 258
" prevents rust, 258
mist, 144
skin, 190
tea-pot, 197
" used by cotters, 198
" set on a hob to draw, 198
will never blister, 190
Blacks, 60
none to railway engines, 60
Blacksmiths strike fire by nails, 96
Bladders inflated by heat, 103
BLAZE, blue, 46
green, 45
yellow, 46
between the bars of a grate, 45
Blazing coals burn quickly, 39
Blood red, 242
purple, 242
Blowers, 70
Blowing cools broth, 180, 247, 312
tea, 248
Blue, 401
glasses, 407
sky, 132
sublimate, 426
Body warm, 87
BOILING, 234
WATER bubbles, 114, 283
makes it flat, 275
is in a ferment, 232
rattles, 116
runs over, 115, 233
swells, 114
one pot will not boil in another, 118
retarded by a spoon, 117
" by salt, sugar, 118
Bottled ale, &c., 268
Brackish water unfit for railway engines, 263
Bread heavy, 276
made with yeast, 276
Breath exhaled, 244
visible in winter, 217
Breathing difficult on a mountain, 255
previous to a storm, 255
BREEZE at watering places, 310
evening, 309
morning, 308
of islands, 309
speed of, 313
(_See wind._)
Bricks for cold feet, 173
Brick stoves, 174
Bricklayers cannot work in a frost, 359
cover new work with straw, 359
Brilliancy, 364
Brine retards boiling, 119
tested, 361
Broth cooled by breath, 247, 312
by convection, 247
by stirring, 247
Bubbles in tea, 419
of boiling water, 114
Bulk for bulk, 110
Burns cured, 157
Burning glasses, 2
Caloric, 1
Cambric handkerchiefs cool, 184
Cambridge, rain of, 340
CANDLES, 74
burn, 74
" blue, 148
cotton, not easily blown out, 79
easily blown out, 51, 78
and rekindled, 51, 55
extinguished, 79
flame hot, 75
" hollow, 76
" pointed, 77
" purple below, 76
" tends upwards, 77
" yellow, 76
gas of, 281
held at a door, 290
hottest _above_ the flame, 79
give light, 76
make glass damp, 78
need snuffing, 81
Palmer's, 80
prevent our seeing abroad, 378
reflected in a window, 379
rush, easily go out, 79
smoke, 81
spirt, 155
suddenly introduced give pain, 365
wax, need no snuffing, 81
Candlestick rags catch fire spontaneously, 58
Capillary veins, 84
Captain Ross, 414
Carbon, 33, 74
Carbonate of lime, 426
of soda, 426
CARBONIC ACID GAS, 37, 108, 249, 264
deleterious, 250, 264
in human bodies, 84
its presence detected, 264
CARBURETTED HYDROGEN GAS, 279, 280
Carpets warm, 169
Carriage wheels catch fire, 99
Carriage windows misty, 213
Casks charred, 73
Cart grease, 100
Cathedral aisles famous for echoes, 417
CATS in wet weather, 147
prowl by night, 367
rub their ears, 150
see in the dark, 367
wink before a fire, 367
Cattle uneasy in wet weather, 148
Caverns famed for echoes, 416
Ceilings sooty, 71
Cellars cold in summer, 256
warm in winter, 256
Cerebellum, 424
Cerebrum, 424
Chalk, 426
CHARCOAL, 72
bad conductor, 166
fire, 72
" deleterious, 265
purifies water, 72
removes the taint of meat, 72
Charring bread, 73
casks, 73
wood, 73
CHEMICAL ACTION, 30
Chestnuts crack when roasted, 104
not if slit, 105
Chimney pots, 71
CHIMNEYS SMOKE, if a room be too close, 61
remedy, 62
in vestries, valleys, 66
remedy, 67
in wind, 66, 111
if too long, 62, 116
" short, 62
" large, 69
remedy, 70
when the draught is slack, 63, 69
when the door is on the same side, 68
remedy, 68
when it needs repairing, 68
sweeping, 68
when two fires are in one room, 65
remedy, 65
China broken by hot water, 125
Choke damp, 264, 279
Church bells heard at a distance, 151
Churchyards smell offensively, 283
Chyle, 242
Cider, 269
Cinders, 43
iron, 43
will not blaze, 48
Cirro-cumulus clouds, 136
Cirro-stratus clouds, 134
Cirrus clouds, 134
Citizens pale, 243
Citric acid, 426
City air unhealthy, 253
Clean kettles, 186
Cleanliness connected with the dietary, 93
Clear day overcast, 304
Clear nights exhilarating, 144
Clocks heard, at a distance, 151, 413
Close rooms unhealthy, 253
Cloth collects but little dew, 208
Clothes gather damp in summer, 211
wet, 157
Clothing for workmen, 164
promotes warmth, 176
CLOUDS, 127
cause of, 129
classes of, 134
colour of, 132
compound, 136
" simple, 134
differ from fog, 128, 227
dissipated, 304
distance from the earth, 129
edges most luminous, 399
electrical, 131
fall in rainy weather, 337
float, 128
height of, 4, 120
highest and lowest, 130
intermediate, 135
light, 120
motion of, 133
red, 132, 399
round mountain tops, 137
thickness of, 130
" how ascertained, 130
vary in shape, 129, 130
" in colour, 133
where most abundant, 129
where least, 129
use of, 137
velocity of, 314
wind affects them, 129, 131
Coal gas, 280
mines explode, 281
Coals black, 403
COLD WEATHER affects the barometer, 328
makes us love fat, 90
" activity, 91
out of doors, 312
promotes hunger, 91
Collapsing, 289
Colour of clouds, 132, 133
Colours vary, 400
some warm, some cold, 187
Combining not mixing, 25
COMBUSTION, _see fire_, 33, 85
cause of, 36
elements of, 36
heat of, 37
increased by wind, 58
in the veins, 84
COMMUNICATION of HEAT, 164
Compound clouds, 136
Compression, 102
CONDENSATION, 98, 102
Condensed air, 289
CONDUCTION, 164
not absorption, 184
CONDUCTORS, best, 165
worst, 166
not absorbers, 185
of lightning, 22
dangerous, 24
CONVECTION, 219, 231
Convective currents, 245
cool broth, 247
cool iron, 247
Cooking vessels with wooden handles, 166
Cooper applies hot hoops, 122
Copper sonorous, 410
tarnishes, 259
COPPER-HOLE, 60
roars, 60
" not when the door is open, 60
Cornea, 388
Corns ache in wet weather, 256
Corpse cold, 95
Corrosive sublimates, 426
Cotton bales catch fire spontaneously, 57
handkerchiefs hot, 184
Countrymen ruddy, 243
Cowls, 67, 111
Crowds produce drowsiness, 251
head-ache, 249
vitiate air, 249
unhealthy, 250
Culinary vessels have wooden handles, 166
should be sooty, 71, 201
Cultivation promotes dew, 210
warmth, 160
Cumulo-stratus clouds, 136, 137
Cumulus clouds, 134, 135
Cup in a pie, 120
why full of juice, 124
Damp banisters, 217
beds, 158
house, 217
DANGER IN A STORM, 12
in attics and cellars, 16
a crowd, 18
theatre, &c., 19
before a fire, 15
near a tree, 12
river, 14
flocks and herds are exposed to, 19
those who bar shutters, 18
lean against a wall, 17
or carriage, 20
who ring bells, 15, 17
run, 15
Dark colours warm, 186
radiate heat, 197
Davy, Sir H., 281
Day-light produces hunger, 88
Dead bodies cold, 95
taller than living, 423
Deal snaps in fire, 107
Decanting liquor, 274
spirting, 274
Depression of spirits, 145
Descent in a diving bell painful, 146
Deserts hot and dazzling, 405
DEW deleterious, 220
differs from rain, 226
distilled after a hot day, 219
especially if the wind is westerly, 218
unequally, 207
in open places, 204
in valleys and hollows, 207
on clothes, 211
cultivated lands, 210
grass, 209
leaves, &c., 208
none beneath a tree, 204, 205
a flower awning, 205
hedge or wall, 205
none in a cloudy night, 204
in a windy night, 207
especially if easterly, 218
none on stones, cloth, 208
deserts, gravel, metal, rocks, wool, 209
Dew-drops round, 223
flattened, 223
roll on cabbages, 223
roses, 224
Digging promotes warmth, 161
Digestion, 91
Dinner covers, 202
Dirt warm, 93
Distant bells heard, 413
clocks, 151
objects appear small, 381, 382
sight, 390
spectacles for, 391
Distance makes things invisible, 384
Distilled vinegar, 426
Divers suffer pain, 255
Diving bell, 146
Doors swell and shrink, 151
Dogs uneasy in wet weather, 147
Dough, 274
set before a fire to rise, 276
Double concave glasses, 389
convex glasses, 391
Draining lands promote warmth, 160
DRAUGHT at a door, 314
key-hole, 314
window, 315
slack, 63, 64, 69
Dreams, 424
foolish things, 424
Drops of rain roll on dust, 155
Drowned men restored, 101
Drums, 411
DRY WOOD for kindling, 44
burns best, 107
snaps about, 107
Dryest months, 328
Dublin, rain of, 340
Duck dry in water, 224
Dunghills hot, 277
Dusty shoes hot, 194
Dyeing changes a colour, 401
Ear-trumpets, 415
EARTH, bad conductor, 181
cool in summer, 182
cracks by frost, 357
crumbles in spring, 358
warm in whiter, 131
Earth-fog, 221
Earthen tea-pots, 197, 198
set on a hob to draw, 198
East wind cold, 302
dry, 303
prevents dew, 218
Eat more in cold, 90
less in warm weather, 91
Echo, 416
Echoes, two or more, 418
EFFERVESCENCE, 269
soon subsides, 275
Egg cracked when boiled, 239
tested, 178, 239
ELECTRICITY affects the clouds, 131, 133
excited by friction, 29
felt at the elbow joints, 27, 29
hot, 3
of clouds, 4
positive & negative, 16
ENGLAND grows warmer and warmer, 160
WINDS of, 300
east dry, 302
morning at watering places, 310
most prevalent, 300
north cold, 312
north-east dry, 305
south rainy, 303
warm, 303
south-west rainy, 304
west rainy, 304
when highest, 301
lowest, 301
_See March wind._
Epsom salts, 426
Esquimaux love blubber, 92
Equatorial current, 298
ETHER, 47
boils, 119
used for freezing, 360
used for inflammation, scalds, burns, 157
European skin white, 191
EVAPORATION, 156
freezes, 360
EVENING CLOUDS, 132
grey, 140
red, 138, 399
EVENING RAINBOW, 141
Evergreens frost-bitten, 230
Ewers broken by frost, 349
EXPANSION by HEAT, 103
Extinguishers, 79
made of paper, 79
Eyes, two, 368
see single, 369
affected by blue glasses, 407
fire-light, 407
the sun, 407
Face soon scorched, 196
Fanning, 179, 313
Far sight, 390
spectacles for, 391
Farriers apply hot shoes, 123
Fat men swim best, 362
Feathers warm, 176
Feeling, 425
Feet cold before a fire, 53
wet dangerous, 157
FERMENTATION, 269
of dough, 276
Fender and fire-irons cold, 185
Fiddle-strings musical, 411
snap from wet, 339
Fine weather braces, 147
Finger feels cold when wet, 157
FIRE black and red, 38, 40
blazes, 39
not in frost, 48
burns blue, 148
cause of, 36
charcoal, 72
damp, 280
effect upon the eyes, 407
extinguished, 54
by water, 107
fiercest in winter, 49
out of doors, 50
grotesque figures in, 40
heat of, 280
how increased, 63
hot, 37
kindled at the bottom, 42
light dazzles, 366
lighted with paper and wood, 41
luminous, 46
poker draws up, 52
radiates heat, 196
red hot, 38
reflected on windows, 379
sun dulls it, 49
thaw dulls it, 50
wind intenses it, 51
_See combustion._
Fire-irons cold, 185
rust, 257
prevented, 258
Fishes ascend and dive, 363
seem nearer than they are, 388
cold, 94
FLAME of a CANDLE, 76
described, 77
blown out easily, 78
damp, 78
hollow, 76
hottest above, 79
pointed, 77
purple and yellow, 76
smokes, 81
Flame of a fire between the bars of a grate blue, 46
green, 45
yellow, 46, 47
Flannel warm, 94
used for foot-warmers, 173
Flash, _see lightning_
Flat beer, 273
improved, 273
Flavour discerned by the taste, 425
Flint and steel, 97
FLOWING WATER freezes slowly, 354
makes rough ice, 354
oscillates, 348
pure, 347
Flower awnings arrest dew, 205
purify air, 253
Flowers smell sweetest at night and before rain, 152
Flues blacked, 238
_See chimney._
Flutes, 412
Fly-poison, 422
FOGS, 225, 226
arrest sound, 413, 414
cause of, 129
differs from cloud, 128, 227
mist, 227
dispersed by wind, 228
by sun, 227
frozen, 231
in autumn, 228
in marshes, 226
valleys, 228
none in a frosty night, 227
Food converted to blood, 242
cooled by the breath, 312
Foot-prints frozen, 350
Foot-warmers, 173
Forked lightning, 5
dangerous, 5
Forests catch fire spontaneously, 102
France warmer than of yore, 162
FREEZING MIXTURES, 360
FRICTION (_see rubbing_), 98
excites electricity, 29
sets forests on fire, 102
Frogs cold, 94
FROST affects barometer, 329
sound, 414
braces, 147
breaks ewers, 349
tiles, stones, rocks, 350
pipes, 351
cracks earth, 357
expands water, 352
prevents fog, 227
warm, 356
Froth of beer, 269, 350
Frozen ruts and footprints, 350
Fruits cool the blood, 92
fall to the earth, 419
pleasant in summer, 92
Fuel for the body, 87
Fumigation for sick rooms, 421
FUR, bad conductor, 166
for clothing, 175
warm, 171
Furnaces of brick, 174
lined with clay, 174
Furr of kettles, 262
steam engines dangerous, 263
Gallery hot, 249, 316
Gas, 112
of candles, 281
Gauze wire of safety lamps, 282
prevents explosion, 282
German silver tarnishes, 260
German tinder, 102
Germany warmer than of yore, 162
Ghosts, 286
Gideon's miracle, 211
Ginger pop, 268
acid, 269
GLASSES broken by hot water, 125
covered with mist, 214
which soon subsides, 215
dulled by a hot hand, 215
by breath, &c., 215
_See spectacles._
Glass a reflector, 194
soon cools, 212
_See looking-glass._
Glauber salts, 426
Gloves, black kid, 188
Lisle thread, 188
Glow-worms glisten by night, 368
GOD'S WISDOM 182, 208, 210, 302, 308, 352, 357
Gold never tarnishes, 260
Goulard, 426
Grapes never ferment, 272
Grass promotes warmth, 161
collects dew, 209
Grate, _see stove_
Gravel collects no dew, 209
Gravity, 419
Gray morning, sign of a fine day, 140
GREASE liked in cold weather, 90
loathed in hot, 92
prevents rust, 258
used for wheels, 100
Green colour, 401
wood does not burn, 107
Grottoes famous for echoes, 416
Ground frost, 229
Growth promoted by moonlight, 220
Gulls fly to sea, 154
to land, 154
Gusty weather makes a smoky house, 71
HAIL, 331, 334
cause of, 335
accompanied with thunder, 335
falls in summer, 335
Hair, bad conductor, 166
covered with dew, 217
Halls famous for echoes, 417
Halo round the moon, 143
Hard work promotes hunger, 88
Hat covered with dew, 217
turned red at the seaside, 344
Hawks see near and far, 392
Hay-stacks catch fire spontaneously, 58
Haze round the sun, 143
moon, 143
affects sound, 414
Head aches in a crowd, 249
itches in wet weather, 150
Hearth-rug warm, 169
Hearth-stone cold, 169
hot, 170
HEAT, 1
and light, 47
affects barometer, 328
sound, 414
animal, 83, 85, 277
applied to the bottom of boilers, 234
effects of, 2, 4, 103
expands water, 352
from beaten iron, 95
LATENT, 31, 75, 96
of candles, 75
dunghills, 277
fire, 37, 277
lime, 278
radiates, 196
sources of, 2
Heavy bread, 160
Hills larger in a fog, 148
HOAR FROST, 228
not found on trees, 230
under shrubs, &c., 230
of frozen fog, 231
on clear nights only, 229
on grass, 229
tombstones, 189, 230
very partial, 229
HONEY-DEW, 220
ants fond of, 221
effects of, 221
injures plants, 221
Hot cloudy night oppressive, 144
Hot weather abates activity, 93
appetite, 90
love for grease, 92
Hottest place at church, 316
Hoops used red hot, 122, 123
Horse shoes fitted hot, 123
Horses strike fire, 98
snuff up air, 152
uneasy in dull weather, 148
Houses catch fire spontaneously, 56
smoke in valleys, 66
Hunger, 88
promoted by cold, 90
day-light, 88
singing, speaking, work, 88
_See appetite._
Hydrogen gas, 34, 74
ICE, 349
lighter than water, 349
grows thicker, 353
dissolved by snow, 357
melted by sun, 126
Ice-bergs famous for echoes, 417
Idiots, 424
IGNIS FATUUS, 285
cause of, 286
Impure water purified, 72
Indian mode of striking fire, 99
Inflammable air, 34, 74
Insensible perspiration, 213
Intermediate clouds, 135
IRON, bad conductor, 185
cinders, 43
contains latent heat, 96
cooled by air, 246
convection, 246
radiation, 246
matches, 96
rust, 257
when most common, 258
prevented, 258
sonorous, 410
stoves, 174
Ironing-box, 155
Islands equable in temperature, 311
subject to wind, 309, 311
Itching in wet weather, 150
Jack o'lanthorn, _see ignis fatuus_
Jet of flame through bars, 45
Juice of lemons, 426
Jungle of Hindostan fatal, 266
Kendal rainy, 340
Keswick rainy, 340
KETTLE boils over, 115
quickly when covered with soot, 186
slowly when clean, 186
when new, 186
bottom should be sooty, 200
cold when water boils, 200
inside white, 200
lid hot, 201
furr, 262
holder, 167
not full after boiling, 115
runs over, 233
through the spout, 115
sings, 113, 233
top bright, 200
Kindling wet, 43
Lakes which never freeze, 355
Lamps, 74
Argand, 83
smoke, 82, 83
spirit, 155
_See candle._
Lamp-glasses, 83
Land air cold, 224, 311
breeze unhealthy, 309
Laplanders clad in skin, 183
LATENT HEAT, 31, 75, 96
Laziness promoted by want of food, 89
by heat, 93
Lead tarnished, 259
LEAVES collect dew unequally, 208
green, 404
light green in spring, 404
in a pond, 419
pale in dark places, 403
promote cold, 161
yellow in autumn, 408
Lid of kettles, &c. hot, 201
Light bread, 276
LIGHT, 363
composed of various colours, 400
divided by a prism, 393
from a flint, 97
of candles, 76
fire, 46
sun, 363
reflected, 364
speed of, 364
sudden painful, 365
LIGHTNING, 3
balls, 6
barks and snaps trees, 27
comes from clouds, 16
from earth, 16
conductors, 22
dangerous, 24
follows dry weather, not wet, 28
forked, 5
fuses metal, 27
kills animals, 7
knocks down churches, 24
maims, 8
passes down the outside of a tree, 14
passes through the inside of animals, 14
purifies air, 27
rare in winter, 28
sheet, 6
summer, 11
common, 28
straight, 6
turns beer sour, 27
not old beer, 27
milk sour, 25
_See danger, safety._
Lilac steel rusts, 259
prevented, 259
LIME and water, 26, 30
burned, 278
hot, 277
purifies bins, 266, 421
sewers, 267, 421
Lime-wash for rooms, 422
Lincoln, rain of, 340
Linen cool wear, 183
dried, 160, 316
Linseed oil boils, 119
LIQUEFACTION, 126
LIQUIDS, 112
bad conductors, 172, 232
cooled, 235
Lisle thread gloves, 188
Liverpool, rain of, 340
LONDON FOG, 225
rain of, 340
Long flues, 110
grass promotes cold, 161
Log of wood, 2
two burn better than one, 44, 52
Looking-glass, 369
Lucifer matches, 284
Lunar caustic, 426
Mackarel scales, &c., 136
Macintosh prevents cold, 158
Madness from starvation, 86
Malt, 270, 272
Man a swimmer, 362
no bigger than a crow, 382
Manchester, rain of, 340
Magpies indicate weather, 153
Marble, 426
MARCH comes in like a lion, 306
goes out like a lamb, 306
dry good, wet bad, 306
flowers undesirable, 307
wind dry, 305
Marsh damp, 280
Marsupium, 392
Meat-covers, 202
MEAT liked in cold weather, 90
loathed in hot, 92
taint removed, 422
tainted by moonlight, 220
MECHANICAL ACTION, 95
Mercury of barometer bright, 260
concave, 325
convex, 325
its rise and fall, 325
METAL collects no dew, 209
feels colder than wood, 168
hotter than wood, 167
fused by fire, 127
by lightning, 27
good conductor, 165
handles burn, 166
reflectors, 193
tea-pots, 197
Milk soured by lightning, 25
Miners' danger, 283
prevented, 265
Mirror, 369
MIST arrests sound, 414
black, 144
cause of, 224
differs from cloud, 128
dew, 222
fog, 227
seems to rise, 222
vanishes at sunrise, 227
white, 144
Mixing not combining, 25
Money hot in a pocket, 168
Monsoon, 300
Months, driest, 328
wettest, 329
MOON, distance and size, 383
largest at horizon, 149, 378
reflected in water, 376
in a well, 374
seems flat, 383
larger than stars, 383
Moonlight makes plants grow, 220
taints meat, 220
MORNING breeze, 308
gray, 140
rainbow, 141
red, 139, 399
streaks, 132
MORTAR, 278
adhesive, 279
crumbles, 358
Motes in a sun-beam, 248
Mould hardened by sun, 163
Mouldiness prevented, 422
Mountains cold, 100, 195
collect rain, 338
famous for echoes, 417
impede respiration, 255
noiseless, 416
Muriate of soda, 426
Musical instruments, 411
flat, 412
Nails for matches, 96
Naves fitted on hot, 122
Near-sight, 388, 391
spectacles for, 389
Negative electricity, 66
Negroes, why black, 190
with black eyes, 190
New kettles boil slowly, 186
Night allays hunger, 88
exhilarating, 144
oppressive, 144
produces cold, 89
rainbow at, 141
Nimbus clouds, 137
Nitrate of silver, 426
Nitric acid, 28, 426
Nitrogen, 36
North wind cold, 302
dry, 303
North-east wind dry, 305, 320
November rainy, 308, 338
Oak attracts lightning, 257
Old people far-sighted, 390
hold objects at a distance, 392
lose their sensation, thought, volition, 425
lose their power of walking, 425
spectacles for, 391
Oil, 74
linseed, 119
of turpentine, 119
of vitriol, 426
One pot will not boil in another, 118
how to make it boil, 118
Oxalic acid, 426
copper, 259
iron, 257
OXIDE of lead, 259, 426
platinum, 261
potassium, 262
silver, 260
sodium, 262
Oxygen, 34
of air, 97
its use, 240
supports combustion, 240
sustains life, 240
Out-of-door work produces hunger, 89
Owls prowl at night, 367
see in the dark, 367
sleep all day, 367
Paleness, 243
Palmer's candles, 80
Paper burns, 41
not always, 44, 53
extinguishers, 79
puckers from wet, 339
used for kindling, 41
Papillæ, 425
Paris, plaster of, 426
rain of, 340
Parlours smell of smoke in summer, 71
Partition walls to arrest sound, 415
Pea-soup fog, 225
PERCUSSION, 95
Perspiration, 89
Petals, 402
Petrels, 154
Phosphate of lime, 284
Phosphorus, 283, 284
PHOSPHURETTED HYDROGEN GAS, 283
Piano-forte, 412
Pickle tested, 361
Pie with a cup, 120
full of juice, 121
Pin puts a candle out, 81
Pineal gland, 424
Pipes broken by frost, 351
Piston, 102
PLANTS collect dew, 208
deleterious in bedrooms, 405
grow out of walls, 316
Plaster of Paris, 426
of stoves falls away, 124
Plasterers cannot work in frost, 359
Platinum, 261
its use, 261
never tarnishes, 261
Plate warmer, 188, 193
Ploughing, promotes warmth, 161
Plumbago, 258
prevents rust, 258
Poison for flies, 422
Poker draws up fire, 52
cold, 172, 238
how to carry it when hot, 237, 238
rusts, 258
prevented, 258
Polar current, 298
Poor averse to cleanliness, 93
ventilation, 94
lazy, 89
Pores of wood, 106
Porter, froth of, 109
set before a fire, 109
stale, 275
Positive electricity, 16
Potatoes, green, 405
yellow, 404
Potassium, 262
burns in water, 262
Primrose, 402
Prisms divide light, 393
Pump handle cold, 168
water hard, 363
Purple steel rusts, 259
its rust prevented, 259
PUTREFACTION, 277, 278
Putrefying bodies smell, 284, 285
Quadrupeds swim, 362
RADIATION, 195
cools iron, 247
Radiators are absorbers, 197
Rags catch fire spontaneously, 58
Railway steamers, 218
RAIN, 331, 336
affected by wind, 337
after lightning, 11
arrests sound, 413
cause of, 326, 336
cools air, 159
differs from dew, 226
falls in drops, 336
fertilizing, 307, 337
from passing clouds, 336
heaviest in summer, 341
least at the poles, 342
melts salt, 346
sugar, 345
most in mountainous places, 338
most in winter, 341
near the equator, 341
not salt, 347
on dust, 223
prognostics of, 137
purifies air, 338
sudden change, 326
RAINBOW, 394, 397
colours reversed, 396
morning, 141
night, 141
two, 395
Rain drops, 336
vary in size, 337
Rain-water smells offensively, 345
soft, 344
stagnant, 347
Rainy months, 308
parts of England, 340
Rattling of kettle-lid, 116
Ray of light divided, 393, 400
Reading aloud produces hunger, 88
RED colour, 401
rose, 401
sky, 132, 399
sun-rise, 139
sun-set, 139
Reflected light, 364
REFLECTION of HEAT, 192, 370
REFLECTORS, 192
help the roast, 194
keep kitchen cool, 194
not absorbers, 192
should be clean and bright, 189, 192
should not be painted, 189
REFRACTION, 386, 394
Refrangible, 132
Retina, 388
Reverberation, 417
Rice for food, 93
RIVERS flow slowest at sides, 348
freeze unequally, 354
never frozen at bottom, 352
not wholly frozen, 353
shallow freeze fastest, 354
seem shallower than they are, 387
warm when frozen, 354
Roast apples, 105
soft, 106
chestnuts, 104
Road dark from a light room, 194
Rocks collect no dew, 209
broken by frost, 350
Room cooled, 159, 315
ventilated, 375
warmed by fire, 237
Rose red, 401
Ross Captain, 414
Rotting leaves promote cold, 161
Rubbing, 99
hands to warm them, 101
melts ice, 101
restores suspended animation, 101
_See friction._
Ruddiness, 243
Ruins famed for echoes, 416
Running, promotes warmth, 87
Running water freezes slowly, 354
makes rough ice, 354
oscillates, 348
promotes warmth, 87
pure, 347
Rush lights easily blown out, 79
extinguished by a pin, 81
RUST, 257
prevented, 258
when most troublesome, 258
SAFETY IN A STORM abroad, 20
at a slight distance from a tree, 20
best to be wet, 22
in a carriage, 20
in bed, 22
in-doors, 21
Safety lamp, 281, 282
Sailors rarely catch cold, 158
St. Bride's church destroyed by lightning, 24
SALT, 426
and snow cold, 357
and water, 31
bad for washing, 343
crackles in a fire, 44
dissolves ice, 357
by water, 346
especially hot water, 346
retards boiling, 118
white, 403
of lemons, 426
smelling, 426
water unfit for railway engines, 263
Sand dazzling, 405
Saturday's kettle boils fastest, 199
Saucepan boils best when black, 199
slowly when new, 199
lids should be clean and bright, 199
Scald cured, 157
Scum of fermentation, 272
Sea-beach healthy in the morning, 310
not healthy at night, 310
Sea before storm, 146
heaves and sighs, 146
not much heated by sun, 296
Sea-gulls, 154
Sea water easier to swim in than fresh, 360
rarely frozen, 355
gives cold, 158
salt, 346
Sea-waves, 312
Sedentary pursuits abate hunger, 90
SEEING in a glass, 369
into a dark street, 366
light room, 378
ourselves in a small mirror, 371
the same object, 365
when used to darkness, 366
Sensation destroyed, 424
of feeling, 425
of taste, 425
Sewers purified, 267
Shade cool, 183
Shadow in water, 371, 372
Shadow larger as the object approaches a light, 379
Sheen, 405
Sheep bleat, 148
Sheet lightning, 6
Sheets wet, 157
Ships out at sea, 385
Shirts of linen, 183
Shoes hot when dusty, 194
Sick rooms purified, 421
Sides of a pond covered with leaves, 419
Swimming, 112
SILVER meat-covers, 202
should not be chased, 202
tarnishes, 260
Simple clouds, 134
Singing of a kettle, 113
of boiling water, 233
produces hunger, 88
Single magpie unlucky, 153
Skin, black does not scorch, 191
white does, 191
itches, 150
Sleep elongates the body, 423
body feels not in, 425
dreams in, 424
ears hear not in, 423
eyes see not in, 423
mind wills not in, 424
tongue tastes not in, 423
Sleet, 332
Slit chestnuts, 105
Smelling salts, 426
SMELLS in wet weather, 152
of church-yards, 283
of putrefying bodies, 284
SMOKE, 39, 59
curls, 59
falls, 152
of fresh coals, 39
lamps diminished, 83
by a glass, 83
rises, 110
useful in cooking, 201
Smoky chimneys, 59
_See chimney._
Smoke-jacks, 112
SNOW, 331
arrests sound, 413
bad conductor, 333
cause of, 331
falls in winter, 332
not in summer, 334
like wool, 175
nourishes the earth, 333
on mountains, 334
soon melts beneath a hedge or wall, 206
use of, 332
warm, 332, 333
white, 334, 402
Snow and salt cold, 31, 357
Soap, 344
cleansing, 344
hard, soft, 344
yellow, 344
Soap-bubbles, 348, 398
change colour, 399
Soapy water bubbles, 348
Soda water, 268, 269
Sodium, 262
decomposes water, 262
Soft soap, 344
Solids, 112
Soot in summer, 71
on ceilings, 71
Sooty kettles, 186
SOUND, 409
affected by frost, 414
heat, 414
arrested by wet, 413
velocity of, 410
diminished by rarity of air, 416
heard best by night, 414
inaudible on mountains, 147
South wind rainy, 303, 320
warm, 303
South-west wind rainy, 304
Sparks from a fire, 106
a flint, 97
a horse-shoe, 98
Spectacles, 389
black, 408
blue, 407
for aged, 390
near sights, 389
Split bells, 411
Sponge swells when wet, 339
SPONTANEOUS COMBUSTION, 56, 57, 58, 85
Spoons become dull, 26
in water, 387
retard boiling, 117
Speaking promotes hunger, 88
Spring best late, 307
water cool, 182
sparkles, 269
Springs prevent freezing, 356
Sprinkling to cool rooms, 159
Stagnant water, 347
full of worms, 347
Stale beer, &c., _see beer_, 275
Stars distance and size of, 383
invisible by day, 368
seem flat, 384
seen in a well, 368, 374
seen on mountains, 376
twinkle, 406
Starvation, 86
produces madness, 86
STEAM, 127
engines burst, 236
invisible, 116, 235
of a kettle, 236
why visible, 117
what becomes of it, 117
STEEL and flint, 97
rusts, 259
prevented, 259
Stillness before a storm, 146
Stirring cools broth, &c., 247
Stockings difficult to draw on when wet, 340
STONES broken by frost, 350
cold, 169
collect no dew, 208
snap in fire, 108
unfit for fuel, 43
STORMS, 146
direction of, 28
places of danger in, 12
safety in, 20
Straw covered over brickwork, 359
over trees, 359
water-pipes, 359
Street dark from a light room, 194
STOVES crack, when lighted, 123
when cooling, 123
of bricks, 174
on a floor, 52, 237
rust, 257
not often, 258
prevented, 258
settings fall away, 124
warm a room, 237
Strata of air, 9
Stratus clouds, 135
Streets seem to meet at bottom, 381
watered, 159
Stucco peels off in frost, 358
Sublimates, 426
Sublimation, 426
Sudden light painful, 365
SUGAR at top of tea melts quickly, 421
left at the bottom of a cup melts slowly, 420
melted by water, 345
especially by hot water, 346
retards boiling, 118
stirred melts quickly, 420
white, 402
of lead, 426
Sulphate of lime, 426
magnesia, 426
soda, 426
zinc, 426
Sulphuric acid, 426
and water, 30
boils, 110
Summer allays hunger, 90
clothes for, 187
creates dislike of grease, 92
love of fruit, 92
lightning, 11
Sun-beams full of mites, 248
SUN affects eyes, 407
dazzles, 364
dulls fire, 40
largest at horizon, 149, 377
not seen in a well, 373
seems flat, 384
source of heat, 2
reflected in water, 375
Sun-rise red, 139
Sun-set gray, 140
red, 138
yellow, 139
Super-acetate of lead, 426
Swallows fly low, 152
Swan dry in water, 224
Swimmers sink, 361
Swimming, 262
Syrup boils, 119
Table salt, 426
Tainted meat cured, 72, 422
water, 72
Tallow, 74
Tarnish, 259
Tartar emetic, 426
Tartrate of potash, 426
Tarts have a cup inside, 120
full of juice, 121
TEA cooled by blowing, 248
by stirring, 247
in a saucer, 163
green deleterious, 423
poison for flies, 423
TEA-POT, bright metal, 197
tarnishes, 260
black earth, 197
preferred by some, 198
set on a hob, 198
Telescopes, 385
Tempest, 146
affects weather, 326
_See storms._
Thaumatrope, 406
THAW affects barometer, 329
cold, 320, 356
dulls fire, 50
Thermometer, 307
Thick clothing unhealthy, 164
THUNDER, 8
after lightning, 12
bolts, 11
deep growl, 10
irregular roar, 9
one crash, 8
rolling, 10
_See danger, safety, storm._
Tigers prowl by night, 367
sleep all day, 367
see in the dark, 367
Tiles broken by frost, 350
Timber charred, 73
Tin blowers, 70
foot-warmers, 173
reflectors, 193
_See reflectors._
Tinder blown, 97
Toast and water, 73
for the sick, 73
Tomb-stones frosted, 230
Tongs rust, 258
prevented, 258
Trade-winds, 198
Transparency, 405
Treble, 412
TREES barked by lightning, 29
collect dew, 208
covered with bass, &c., 359
look more distant in a fog, 148
promote warmth, 161
purify air, 253
shade of, cool, 183
Tumblers, _see glasses_
Twilight, 399
Two eyes, 368
see single, 369
Unslit chestnuts, 104
Use of barometers, 317
clouds, 137
smoke in cooking, 201
snow, 332
Valley chimneys smoke, 66
VAPORIZATION, 126, 127
Vapour of a carriage, 214
of a room, 212
of sea not salt, 163
Vats fatal, 265
Vegetable and animal life co-dependent, 244
Vegetables collect dew, 208
cool the blood, 92
Velocity of clouds, 314
light, 364
sound, 410
wind, 313
Vent peg, 273, 274
VENTILATION, 315
sought by the well-fed, 94
not by the ill-fed, 94
Verdigris, 426
Vertical sun, 293
Vestry chimneys smoke, 66
Violets blue, 402
Walls wet in winter, 216
Want connected with dirt, 93
Warm clothes, 187
some things more than others, 165
Wash-hand-basin, 171
Washing, water for, 275
should not be hard, 343
WATER, 38, 342
and lime, 30
and sulphuric acid, 30
ashes soften, 345
bad conductor, 171, 234
boiling, 119, 232, 234
bubbles, 114, 233
rattles, 116
runs over, 115, 233
sings, 233
cleans dirty linen, 344
cold, 177
converted to steam, 127, 343
cools slowly, 225
deep, freezes slowly, 356
dried up in summer, 162
expands by frost, 351
by heat, 351
extinguishes fire, 54, 107
flat when boiled, 275
fluid, 342
flowing, pure, 347
for washing, 275
freezes at the surface, 253
hard, 343
unfit for washing, 343
how preserved cool, 191, 202
hot, 191
heated, 232
intenses fire, 54
mixed with salt, boils slower, 119
not heated above boiling, 235
of a spring cool, 182
purified, 72
purifies bins, &c., 267
salt, bad for washing, 343
shallow, freezes fastest, 355
slackens flame, 55
soft, 344
best for washing, 345
sparkles, 269
stagnant, 347
full of worms, 347
stale, 275
swells with boiling, 114
will not bubble without soap, 348
warm when frozen, 354
Water pipes broken by frost, 351
covered with litter, 359
Watering plants by the saucer, 420
streets, 159
Waves, 312
Wax, 74
Wax candles need no snuffing, 81
Weather affected by tempests, 326
prognostics of, 137
told by barometer, 318
rules, 319
Weather toys, 339, 340
Well, moon seen in, 374
stars seen in, 368
sun not seen in, 373
West Wind promotes dew, 218
rainy, 304, 320
Wet clothes cold, 157
feet dangerous, 157
finger cold, 157
kindling, 43, 44
sheets, 158
summer, cold winter, 160
weather offensive, 145, 148
Wettest months, 329
Wheels catch fire, 99
greased, 100
kept cool by water, 162
Wheel-ruts frozen, 350
Wheelwright, 122
WHITE, 402
blisters, 190
body linen, 186
crust on clothes, 163
dresses for summer, 186
not fit for winter, 187
mist, 144
vitriol, 426
WICKS cotton, need snuffing, 81
have a knob when long, 80
not upright when long, 80
Palmer's wicks need no snuffing, 80
smoke, 82
_See candles._
Will o' the wisp, _see ignis fatuus_.
WIND, 287
affects barometer, 327
clouds, 129, 131
after lightning, 11
altered by clouds, 295
by seas, 295, 296
brings dry, 305
rain, 305
cause of, 287, 292
changes the shape of clouds, 132
cold, 117, 180, 312
dispels clouds, 131, 138
fog, 228
draws up fire, 51
dries linen, 316
feels hot sometimes, 181
in England, 300
increases clouds, 131, 138
makes barometer fall, 320
chimneys smoke, 66
of a morning, 308
of an evening, 309
prevents dew, 206
rate of travelling, 313
regular, 297
_See England, monsoon, north, south, west &c., trade-winds &c._
Winding passages famed for echoes, 417
Windows blazing with the sun, 372
not at noon, 372
covered with frost, 214
mist, 211
carriage, dull, 213
rattle, 418
Wine glasses, _see glasses_
Wine made without yeast, 271
Winter clothing, 187
promotes hunger, 90
WISDOM of GOD, 182, 208 210, 352, 357
WOOD burns, 41
spontaneously, 55
charred, 73
hot at one end, cold at the other, 165
ignited by friction, 99
kindling, 41
dry, 44
wet, 107
two logs burn best, 44, 52
sends forth sparks, 106
will not melt, 127
Wooden handles, 166
WOOL bad conductor, 166
collects no dew, 209
warm, 176, 333
Woollen clothing, 175
Work produces hunger, 88
Yeast, 271
makes light bread, 276
not used in wine, 271
Yellow flame gives best light, 47
soap, 344
sun-set sign of wet, 139
FINIS
JARROLD AND SONS, PRINTERS, NORWICH.
Transcriber's Notes:
Archaic and inconsistent punctuation and spelling retained.
Inconsistent question formats were regularized.