After these many weeks have passed, the pots containing the white
powder of carbonate of lead, as it is called, is taken out of the
building where corrosion took place, and the white deposit is put
through an elaborate system of refining, which is called “washing,”
and, in fact, is really washed in water, and is then dried in very
large copper pans. After being dried it is in the form of large white
cakes, resembling pieces of chalk. These cakes are then passed through
a mill, which grinds them to very fine powder, which is packed in
barrels ready to be shipped and used by the paint-maker.]
[Illustration: FURNACE WHERE THE SULPHUR IS ROASTED OUT OF THE ORE.
Now that we have followed through the process of making the white-lead
powder, or pigment, let us take a little time to study the preparation
of the other white powder, known to the paint trade as “oxide of zinc.”
This is prepared in a manner quite different from that of the white
lead.
First the ore which is mined from the earth containing the metallic
zinc is carefully selected by expert workmen and placed in a special
kind of furnace, being mixed with hard coal, such as we use in our
heating stoves.]
[Illustration: A ZINC SMELTER--THE MEN KEEP THEIR MOUTHS COVERED SO AS
NOT TO INHALE THE VAPOR, WHICH IS POISONOUS
The burning of the coal causes an intensely high temperature, sometimes
being several thousand degrees. This causes the zinc ore to be consumed
as it were or to pass into a form of vapor. This vapor is carried
through huge pipes which are several feet in diameter and extend for
a long distance. While these vapors are passing through these pipes
it becomes cooled. After becoming cooled it takes on the form of very
fine white powder, coming from the pipes in much the same way that
snow falls from the sky in the winter. This is collected and placed in
barrels, after which it is ready for the paint-maker without further
preparation.]
~WHERE LINSEED OIL COMES FROM~
Since we have followed the preparation of the two important white
pigments used in making our can of paint, it is now important that
we devote a little thought to the liquid which is to be used. This
is called “Linseed Oil.” Linseed oil is of a golden yellow color,
resembling the appearance of thin syrup which we sometimes have on the
table. This oil is taken from the seed of the flax plant. It might
better be called “Flaxseed Oil,” yet it is not commonly known by that
name, but is nearly always referred to as “Linseed Oil.” Flax is grown
in many parts of the world, the most important places being the United
States of America, Dominion of Canada, Ireland, India and the Argentine
Republic. In the United States, the seed is sown early in spring, much
the same as is done with other crops, and ripens and is harvested early
in the fall of the year. The harvesting and separation of the seed from
the plant or straw is done very much in the same way that other crops,
such as wheat and oats, are harvested. The seed is then taken to market
and is ready for the extraction of the oil, which is done by men who
are known as “oil crushers.”
[Illustration: PRESSING OIL OUT OF FLAXSEED.]
[Illustration: REMOVING OIL CAKE FROM PRESS.]
The oil is extracted from the seed by a very simple process. Usually
the seeds are heated by steaming them, after which they pass through
a mill, being ground to a coarse mass, which is then placed in very
powerful machines called “Hydraulic Oil Presses,” which squeeze the oil
from the seed, leaving the remainder in the form of large cakes which
are then ground to a mealy-like powder which is used as food for cattle
and is very much prized.
The oil which has been extracted by this process is put into large
tanks where it is clarified and is then ready for the paint-maker.
This oil is often referred to as “Vegetable Oil” and it has one very
peculiar and very important characteristic which makes it useful and
necessary for use in paint. This property is that of drying or becoming
solid, losing all tendency to stickiness after it has been spread out
thinly and exposed to the air for a short time.
[Illustration: WHERE LEAD IS GROUND IN OIL.]
[Illustration: WHERE PAINTS ARE MIXED.]
Now that we have given attention to the preparation of the most
important things used in the making of our can of paint, let us look a
little to the manner in which they are put together, and the result.
The oil is necessary in making paint in order to make it fluid, so that
the paint may be brushed on to the wood or other surface, and also so
that the pigment or powdered material which has been put into the paint
will have something to hold it to the surface. The oil or other liquid
which may be used is usually called “Binder” by the paint man because
it binds the pigment in the paint and to the surface on which it has
been spread or applied.
In a large paint factory, the two white pigments, lead and zinc, are
mixed with linseed oil in large machines known as “Mixers” into a
smooth paste which is then run through other machines called “Mills,”
where the paste is ground very fine into large tubes where the paint
is finished by mixing in enough more oil to make it of the proper
thickness or consistency for brushing. In this state it can be used,
but would not be entirely satisfactory because it would dry very
slowly. For that reason, the paint-maker adds in a small amount of what
is known as “Drier,” which causes the paint to dry much more rapidly
after it is spread out on any surface.
The paint-maker may also add in a small amount of thin liquid called
“Turpentine,” which also aids in the drying and the working of the
paint. Turpentine is a very thin liquid which looks like water, and it
is derived from the sap of one species of pine which grows abundantly
in the southern portion of the United States. The sap is taken from the
tree by tapping the tree or making an incision called a box, at certain
seasons. After the sap is collected it is put through a heating process
called “distilling,” which separates the water-white liquid, called
turpentine, leaving a large mass of heavy material which is commonly
known as “Rosin.” This turpentine is very useful to the paint-maker and
the painter. It is also used for many other purposes.
~WHAT MAKES THE DIFFERENT COLORS OF PAINT~
The paint which we have described is the most simple kind and is white.
There are many other kinds of paint used, being of many different
colors. All of these different kinds require different treatment and
preparation and would require many large books to explain even in a
brief way.
The white paint which we have described may be colored or tinted to
many different hues by adding suitable color pigments. These color
pigments are of many kinds and are derived from many different
sources. The vegetable kingdom is represented as well as the mineral
and animal kingdoms. The linseed oil which we have already mentioned,
is derived from the vegetable kingdom. This also applies to some few
of the pigments. A very important instance which we might mention
is a beautiful rich brown called “Vandyke Brown.” This is made from
decayed vegetation which is found in swampy districts. There are many
pigments derived from the mineral kingdom. White lead and zinc oxide
have already been described as useful. Among colored pigments coming
from this kingdom, we might mention yellow ochre, sienna, umber, cobalt
blue, and many others.
The animal kingdom supplies quite a number, one of which is a beautiful
red known as “Carmine.” This is taken from a small insect or fly which
is found in certain tropical climates. The production of carmine is
very expensive and the product is highly prized.
Another important development of the animal world is what is called
“Bone Black.” This is made by taking ordinary animal bones, putting
them into a suitable furnace and burning them, which really produces
bone charcoal, which is refined by powdering and washing, and finally
produces a beautiful black, such as used for painting fine coaches and
carriages.
Why Does a Dog Turn Round and Round Before He Lies Down?
Away back in the history of the animal kingdom, when the ancestors of
our domestic dog were wild, they slept in the woods or open. When they
were ready to lie down, they first had to trample the grass about them
flat to make a place to lie down. This became a habit and one of the
instincts of the animal which has been transmitted to the dogs of today
who keep it up. It is an inherited habit quite useless to the dogs of
to-day.
How Is Light Produced?
You already learned that a substance called ether is found in all
substances, filling the spaces between the molecules. When the
molecules are made to vibrate, the ether naturally also vibrates. As
soon as the vibrations become sufficiently rapid, they produce the
sensation of light. These vibrations also produce heat. In heated
bodies the molecules are always found to be in vibration, and a body
may become so hot that it gives off light. We notice this when iron
becomes red hot. Heat and light are found together in bodies in many
instances. In fact, most of the light we have comes from bodies which
are hot. The sun is so hot, that it is surrounded by the gases of many
substances that exist as solids on earth.
We have some bodies which produce light which is not accompanied by
much heat. The glow-worm, or firefly, seems to make light with little
or no heat; but we do not yet know how this is done. Almost all
sources of artificial light require that heat be produced before light
obtained. Only such vibrations of the ether which are sufficiently
rapid produce enough light to enable us to see. For this reason,
a piece of red hot iron, which is made luminous by heat and whose
particles vibrate less rapidly produce little light.
What Makes Rays of Light?
Whenever the ether is made to vibrate rapidly enough at any point,
the vibrations go in straight lines from the source of light in all
directions. A single line of vibrating particles in the ether, is known
as a ray. A number of rays, that issue from one point, are said to form
a pencil. A pencil of light may be produced by holding near a candle a
screen, with a hole in it. Sometimes rays of light are brought together
in a point, as may be done by means of a burning glass, and one of
these bundles of rays is known as a convergent pencil.
A bundle of rays that lie parallel to each other forms a beam. The rays
that come to us from the sun are practically parallel and are called
sunbeams.
Why Does a Nail Get Hot When I Hammer It?
When we are in the sunshine, or standing before a fire, we feel hot;
when we take snow or ice in our hands, they feel cold. The thing which
produces these sensations is called heat. When we feel heat, it is
because heat is absorbed by our bodies, and when we feel cold, it is
being thrown off by them.
To answer this question, we must see how heat may be produced. If we
draw a cord rapidly through our fingers, they feel hot, and if we rub
a coin briskly with a cloth or our hands, it becomes warm; if we take
a nail and hammer it on a hard substance, it becomes too warm for us
to hold. In these instances heat is produced by retarding or checking
the motion of a body. When we draw a cord through our fingers, it moves
less easily; we retard its motion by gripping it and this is what makes
the heat we feel. When we strike the nail with a hammer, the motion of
the hammer is checked by the nail, and the faster we pound with the
hammer, the hotter the nail becomes. From these experiments we learn
that whenever the motion of a substance is checked, or retarded, heat
is generated, and the substance made hot.
In explaining this method of producing heat, it was at one time thought
that all bodies contained a substance which produced the heat and that,
when rubbed or hammered, this substance was thrown off. About the
end of the 18th century, however, it was shown by Benjamin Thompson
(Count Rumford), that substances when rubbed give off heat. From this
we learned that heat is not a substance, because the quantity of
any substance, present in a body, cannot be limitless. If it were a
substance which produced the heat, the supply would sooner or later be
exhausted, and rubbing could no longer produce heat.
Heat produced by rubbing, or by striking substances together, is
caused as follows: If two substances are struck upon each other,
the whole of those substances are checked, but the molecules of the
substances are made to vibrate very rapidly, and these vibrations
produce the heat we feel.
How Do We Obtain Heat?
We get most of our heat from the sun. If the heat from the sun did
not reach us, no living thing would exist on the earth. No plants or
animals could live; the oceans and rivers would be solid ice.
Another important source of heat, is chemical action. Chemical action
is what causes fire. Even when it does not cause fire, it produces a
great deal of heat. When we breathe to keep our bodies warm, it is
a chemical action that occurs. Fire is the most important form of
chemical action, as a source of heat.
Why Does a Glow-Worm Glow?
A glow-worm is a kind of beetle which may be found in the yards and
hedges in the summer time. The name applies only to the female of
the species which is wingless and whose body resembles that of a
caterpillar somewhat and emits a shining green light from the end of
the abdomen. The male of this species has wings but does not show any
light as does the female and resembles an ordinary beetle. The male
flies about in the evenings looking for the female and she makes her
light glow in order that the male may find her. Glow-worms are found
mostly in England. There are, however, some members of the same species
of beetle common to the United States. We speak of them as fireflies
or lightning bugs. The female of these also is the only one carrying a
light, although unlike the glow-worm she has wings and can fly.
Why Do They Call It Pin Money?
This expression originally came from the allowance which a husband gave
his wife to purchase pins. At one time pins were dreadfully expensive
so that only wealthy people could afford them and they were saved
so carefully that in those days you could not have looked along the
pavement and found a pin which you happened to be in need of as you can
and often do today.
By a curious law the manufacturers of pins were only allowed to sell
them on January 1st and 2nd each year and so when those days came
around the women whose husbands could afford it, secured pin money from
them and went out and got their pins.
Pins have become so very cheap in these days that we are rather
careless with them, but the expression has continued to live although
today when used, it means any allowance of money which a husband gives
a wife for her personal expenses.
Pins were known and used as long ago as 1347 A. D. They were introduced
into England in 1540. In 1824 an American named Might invented a
machine for making pins which enabled them to be manufactured cheaply.
About 1,500 tons of iron and brass are made into pins every year in the
United States.
Why Do People Shake Hands With the Right Hand?
In the days of very long ago when all men were prepared to fight at any
and all times because one could not know whether another approaching
was a friend or an enemy, all men went armed. This was before the day
of guns when the sword was the great weapon of defense.
Upon occasion when one man approached another, each had to decide
whether the other came on a peaceful mission or not.
People in those days were mostly right handed as they are now and when
fighting carried their swords in their right hands.
If, then, a man wished to speak with a stranger or, as might easily
be necessary, to one who may even be known to be unfriendly, he put
out his right hand upon approaching to show that he had no deadly or
dangerous weapon in it. The other man could see this and knew from the
extended open hand that no harm was intended and that the approach was
peaceful. If, then, he was willing to meet the other, he also extended
his right arm with the hand open to show him who was approaching that
his fighting hand was empty also; and when they met each would grasp
the hand of the other so that neither one could change his mind and
assume a fighting attitude without the other having an equal warning.
How Did the Custom of Clinking Glasses When Drinking Originate?
In the days of the Roman gladiators, before a duel with swords, it
became the custom of each of the participants to drink a glass of wine
before fighting. Just before the fighting commenced two glasses of wine
were brought and the gladiators drank. These two glasses of wine were
provided by the friends of either one or the other of the gladiators.
To guard against treachery, through some over zealous friend of the
fighters furnishing poisoned wine was necessary. So before drinking and
to show there was no treachery, the gladiators came close together and
poured wine from one glass into the other back and forth until the wine
in the glasses was thoroughly mixed. If the wine in one glass then had
been poisoned, the poisoned wine would thus be in both glasses, and if
there had been any treachery, both gladiators would be poisoned if they
drank. The wine was poured from one glass to the other to show that
there was no treachery.
This custom continued in use for a long time until the idea of
drinking before a fight was abandoned. The custom, however, of showing
friendliness in this way while drinking continued for a long time.
Later it became a mere custom, however, to show a friendly spirit
toward the one who was drinking with you, and when the danger of
poisoned wine was past, the actual act of pouring the wine from one
glass to another was changed to merely touching the glasses together.
Thus today we have the friendly custom of touching glasses together
long after the necessity of guarding against treachery while drinking
has passed.
Why Cannot Fishes Live In the Air?
It is a curious thing isn’t it that if a boy falls into the water, he
will drown if he cannot swim or someone does not help him out, and that
if a fish falls out of the water onto the land, he will drown also,
even though he knows how to swim, better than anything else he does. A
boy cannot secure the air which he needs to live on if he is under the
water, because there is not enough air for him there and a fish cannot
secure enough air for him to live on when he is on land where the air
is plentiful, because, the boy takes his air from the air itself and
the fish gets his air out of the water.
To live by breathing the air we find on or above the land, it is
necessary to have lungs and fishes do not have lungs. In the case of
the boy under the water he would have to have gills to enable him to
make use of the air which is in the water to live by and he has no
gills.
A fish can only live a little while out of the water, but even so he
can live longer out of the water than a boy can under the water.
Lest you read sometime of the flying fish and think they must be able
to live out of the water, I will tell you before you ask the question
that the flying fish never stays out of the water for more than a few
seconds at a time. His flying leaps amount to little more than long
leaps from wave to wave. He swims along very fast in the water, coming
right up to the surface and out into the air and the speed at which he
has been swimming regulates the distance he will go when he shoots into
the air, as he has no means of propelling himself through the air, but
only into it. He has, however, wing-like fins, which he spreads out
when in the air and which enables him to glide through the air and thus
remain in the air longer.
What Makes a Fish Move in Swimming?
This is a puzzling question, I am sure. Of course, you at once cause
several other questions as soon as you ask this one such as the
following: Does the water in front of him move out of the way and then
close in behind him? If so, where does it go in the meantime? Does the
fish move the water forward or up or down or what does he do?
The answer is, of course, in the movements of the fish’s tail. The fish
in swimming is surrounded with water, top, bottom and all sides of him.
The pressure of the water on the fish is the same at all points so that
any motion made by him would have a tendency to make him move. As a
matter of fact the tail in moving from side to side creates a current
in the water from the head to the tail, or rather would produce an
actual current if the fish remained perfectly still. Instead of making
an actual current of water, the body of the fish is moved forward.
As to whether the water ahead of him opens up first and then the water
behind him is a more difficult question to answer. To the appearance it
would seem as if the water moved at both ends and sides at once, but
according to scientific theory, the water at the head of the fish is
displaced first.
Why Are Birds’ Eggs of Different Colors?
This is a wise provision of nature to help the mother birds hide her
eggs away from the eyes of her enemies. In the animal kingdom every
kind of life is the natural prey of some other kind of animal. A bird
will have enemies which try to catch her as food. A bird cannot fight
back, so must fly away when danger threatens, in order to save her
life. This means that she must leave the eggs in the nest for the
time being. At certain times she must also leave her nest and search
for food for herself. In order that the eggs so left alone may have a
better chance of not being discovered, nature has arranged matters so
that the eggs take the color very much of the surroundings in which
they are laid. Eggs of some birds are spotted or look like pebbles,
because the mother bird lays them in the sand. Some of them are green,
almost the color of the materials from which the bird builds the nest,
and so the colors have a real, and to the birds, a valuable purpose.
Why Does a Hen Cackle After Laying an Egg?
The hen cackles because she is glad. She is glad because she has just
accomplished something, which she was put on earth to do. If you study
the life on the earth carefully with this in mind, you will discover
that all kinds of life give expression in some form of gladness, when
they have performed the things they are on earth for. It’s the hen’s
way of expressing herself and letting the chicken world know. The dog
wags his tail when he is pleased; boys and girls jump up and down when
they are pleased, whether they have been doing anything commendable or
not. No doubt also the actual laying of the egg causes some discomfort
to the hen and the corresponding feeling of gladness would come
naturally after the discomfort disappeared.
Why Will Water Run Off a Duck’s Back?
The reason that water runs of a duck’s back, is that the feathers of
ducks are oily and, as water and oil will not mix, the water runs off
instead of soaking in. The feathers on a duck are so thick on the body
of the duck, top and bottom, that even if it were not for the oil which
is on the feathers the water would have some difficulty in soaking
through the feathers. But the main reason why the feathers on a duck’s
back cause water striking them to run off is that the duck has an oil
gland which is constantly producing grease or oil and which the duck
uses in giving his feathers a thin coating of oil to make them slick
with oil and when any water strikes the duck it runs off. Other birds
which live in the water a great deal have this oil gland for the same
reason.