Paint such as is most frequently used is the material used for painting buildings, such as houses, barns, stores, and many others which we need not mention here. This paint is used on these buildings mostly for two very important reasons—one being to beautify the buildings, the other being to protect them from the ravages of the weather, much in the same way that your clothes protect you from the weather.

Paint such as we mention here may be regarded as the most simple and useful form. You have no doubt frequently seen the painter-man spreading paint on some building, or perchance, you have seen your father doing it, and have noticed that paint is a fluid substance looking something like cream, which is applied to the surface to be painted with a suitable brush and is brushed out smoothly. After the first coat is dry, other coats are put on in the same way until enough paint has been put on to thoroughly hide the unevenness of the lumber and making it of a uniform color.

This paint is made by simply mixing together dry powder, which is usually called pigment, with a thin, yellowish liquid which is called linseed oil. In the earlier days, the painter-man mixed this paint himself whenever he desired to use it. In these more modern times, he usually buys this paint already prepared.

Perhaps a little history of the preparation of the package of a can of paint which he buys may be interesting to you.

Let us imagine that the can of paint is white. In this case, the pigment which is used is a white powder and is made of either metallic lead or metallic zinc. The preparation of this fine white powder is very interesting and requires considerable time to perfect.

Let us consider the pigment known as white lead first. This is produced by causing metallic lead, which is of a bluish-gray color and very heavy, to change from its original form by a process which is known as “corrosion.” This corrosion is brought about by first taking the metallic lead, which at this stage exists in large pieces known as “pigs.” These pigs of lead are melted in a furnace and then molded into small, thin shapes which are buckles.

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.”

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.

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.

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.