Chapter V: Part 5

This is an illustration of a method of excavating and loading marl and clay to be manufactured into Portland cement. The large bucket suspended over the cars does not gouge into the hillside as shown in the preceding picture, but descends like a huge steel hand, the metal parts opening and closing like fingers. The long derrick elevates the bucket and swings it over the train of cars.]

This is a view of the electric motors operating the grinding machines which reduce the raw material to a very fine powder. There are various types of mills or grinders, to which the material comes after going through the rock crusher. They grind it in preparation for the kilns.]

This is an ingenious machine which bags and weighs the cement. The bags are suspended as shown, and when filled and weighed by the machine are placed in barrels and shipped to their destination. Every device of this kind that will save time and labor cheapens the cost of manufacture.]

This picture shows how concrete houses or walls are built through the use of what are known as forms. In building a wall we have an inside and outside form, as shown in the picture, between which the concrete is placed. After it hardens the forms are removed. In some operations, such as the construction of a large factory building or great bridge, there is such a vast array of timber construction as to make the scene quite impressive, especially when bridge arches of great span and height are under construction.]

This is a curious example of concrete construction. It is a coal pocket, from which locomotives are supplied with fuel. Railroad companies have adopted it because of its great strength and durability.]

This is an interesting example of concrete construction. It is a large water tower which will never warp, rust or decay. In this field concrete has been of great service, whether reservoirs are constructed in the form of towers or tanks. As already stated, water does not affect the life or strength of concrete, except to improve it.]

MECHANICAL CEMENT MIXER]

Our two last pictures relate to an exceedingly important and rapidly increasing use of cement. It is the construction of concrete roads. The first picture shows a concrete road in course of construction. The mechanical mixer referred to above is shown in this picture. It is a self-propelling machine and mixes the concrete very rapidly. As it comes from the mixer in a wet and mushy mass it is placed between rigidly staked side forms, where it hardens into imperishable rock. The road is brought to its shape by working to and fro a long plank called a template, after which the surface of the road is troweled with wooden floats, giving it a texture which prevents horses and cars from slipping. The last picture shows a narrow concrete road in the state of Maryland. Wherever these roads have been built they mean much to the women and children of the community. They never grind up into mud or dust, and are as pleasant to walk upon as the sidewalks of the city. Children, especially, delight in them. In Wayne county, Mich., where they have the most celebrated concrete roads in the world, the children go to and from school on roller skates, and various games are played on the concrete road.]

Why Don’t We Make Roads Perfectly Level?

Roads are made with a curving upper surface, i. e., higher in the middle, in order that the rain will drain away from the road into the gutters or ditches which you find at the sides. You see water has the faculty of running only in one direction, and that is downward. If it cannot go down on one side or the other, it will collect in puddles and make the road impassable. For this reason we build our roads so they are higher in the middle than at the sides--not much higher; only about six inches or so--giving them just the gentle slope toward each side that is necessary to allow the water to run off gradually, but sufficiently sloping to keep the water from collecting in puddles in the road. Thus after the dust has been settled by the first rain that falls, most of the surplus rain that falls on the roads finally runs into the ditches at the side of the road.

Why Are Some Roads Called Turnpikes?

Undoubtedly the name turnpike as applied to some roads arose from the fact that pikes or gates were set across the roads by the keeper or toll-collector. In addition to collecting tolls, it was a part of the toll-keeper’s business to keep the road in repair. His wages and other expenses for doing this were received from the tolls collected from the people who used the road to ride on in carriages, wagons, etc. In the early days the toll-collector was armed with a pike, a long-handled weapon with a sharp iron head, which he used to prevent people who travelled his road from going by without giving up their toll. Later on a swinging gate was built across the road, which made it unnecessary to use the pike, though the name was retained, for no one could pass while the gate barred the way. When the passerby had paid his tolls, the toll-collector opened the gate and let him pass. If he did not pay the gate remained closed and the driver had to turn back or decide to pay. Hence comes the name turnpike. In some parts of the country they call these toll roads.

What Is Dust?

A large part of the dust we see in the roadway when the horses kick it up, or when an automobile passes, is made up of the pulverized dirt of the roadway. It becomes mixed with other things, such as the street deposits of animals, particles of carbon, etc. Particles of this dust get into our throats, and as there are many germs in it, they are very liable to cause sickness, especially the colds from which we suffer.

What Becomes of the Dust?

The dust of the roadway is generally blown away by the wind, to come down to earth again wherever the wind happens to carry it--on the lawns, the doorsteps or back to the road, perhaps. In any event, the rain which is certain to come sooner or later, washes this dust back into the soil, or into the sewers. Part of it mixes with the soil. The organic matter in dust helps to fertilize the soil, and is therefore useful. Other parts of the dust are oxidized and consumed by the air, through the heat of the sun. So you see the dust is continually changing from one thing to another.

Are Stones Alive?

Real stones are not alive. They do not become stones until they have been burned out--until they have become what is known as dead matter. This is meant entirely in the sense that we commonly think of the meaning of the word “alive,” which is to be able to breathe and grow. Stones can neither breathe nor grow. They belong to the inanimate kingdom of things on the earth. Particles of this dead matter, found in stones, etc., are in many cases taken up by things that are actually alive, and help to form the bodies of living things.

The most common thing to be found in rocks and stones is what is called “silicon,” and we find this silicon in the straws of the wheat, oats and corn, and in many other things, but not in a way that can be detected except by chemical analysis. A great many of the things found in stones are found in living things, but rocks and stones are not alive in any sense.

What and Why Is Smoke?

Smoke is produced only when something which is being burned is burning imperfectly. If we were to put anything burnable into the fire and establish just the right amount of draft, and knew how to build our fires properly, there would be no smoke and very little ashes.

In the case of the black coal smoke which we think of mostly when we think of smoke at all, the black portion is principally little unburned particles of coal which pass up the chimney with the gases which are thrown off when the coal is being burned. These gases would be invisible--they really are invisible--if it were not for the little particles of coal which are drawn up the chimney with them. If you look at the chimney from which a wood fire expels the gases you find the smoke very light in color--showing that not so much unburned matter is being thrown off. A charcoal fire makes no smoke, because the charcoal has had the unburnable things taken out of it beforehand, and the charcoal stove is almost perfect in construction from the standpoint of combustion.

Of course, the thickness of the smoke from a coal fire is often increased by the fact that there are unburnable things mixed in with the coal, some of which also pass off through the chimney.

Why Can’t We Burn Stones?

We cannot burn anything that has already been burned, and a stone has already been burned. To understand how this is we must first find out what takes place when a thing is burned. When a thing is burning it means merely that that particular thing is taking into its system all of the oxygen of the air that it can combine with. When it has done this it cannot be burned any more. Of course, in doing this the thing originally burned changes its character. The elements in a candle when lighted mix with the oxygen in the air and disappear in the form of gases. The elements in coal mix when fired with oxygen and change into ashes, gases and smoke. A stone, however, is the result of a burning that has already taken place. The original element of most of the rocks and stones we see was silicon, and when that combines with oxygen, the result is some form of rock, which you may be able to break up or throw, but which you cannot burn again.

What Is Fog?

The fog which we generally think of when we speak this word is the fog at or on the sea or other body of water--the one that makes the ships stand by and blow their fog horns. A fog of this kind is nothing more nor less than a cloud, come right down to earth and spread out a little more. People who have gone up into the air in balloons and other airships through the clouds, say that the clouds are only fogs, and that above them it is as clear as it is on a sunshiny day on the water when there is no fog.

There is another kind of fog which settles down over the land, especially in the cities. It is a damp mist which combines with the smoke and other impurities in the air and forms a black and dirty cloud about everything. This occurs when the upper air prevents the smoke which rises from a city with all its people and fires in the furnaces from passing up and away. The upper air acts like a blanket and keeps the misty, smoky air down, until the wind comes along and blows it away.

What Becomes of the Smoke?

There are a number of things in smoke, and when we know what they are, we will find a natural answer to this question. First, there are, of course, the little unburned particles of fuel which get carried up the chimney by its drawing power. These naturally fall to the ground of their own weight, once they get beyond the drawing power of the chimney and out of the current of air so formed. Some of the gases are already quite burned out when they pass up the chimney. There is a lot of carbonic acid gas which, of course, mixes with the air and eventually becomes food for the plants. Then there are some gases which are not entirely burned, and the air burns them still more until they, too, become carbonic acid gas, or water which is also thrown off by a burning fire.

Why Does an Apple Turn Brown When Cut?

The reason is that when you cut an apple, the exposure to the air of the inside of the apple causes a chemical change to take place, due to the effect the oxygen in the air has on what is scientifically known as the enzymes in the apple, or what are commonly called the “ferments.” When the peel is unbroken it protects the inside of the apple against this action by the oxygen. The brown color happens to be due to the chemical action. The action is similar to the action of the air on wet or damp iron or steel, in which case we call it rust.

Why Does a Piece of Wood Float in Water?

A piece of wood will float in water because it is lighter than the same amount of water. We do not mean that a piece of wood weighing one pound, for instance, would weigh any more than a pound of water, of course, but if you took the measurements of each you will find that it took less bulk to make a pound of water than of wood. If you had a piece of wood so shaped that it just filled a glass completely, and then took another glass and filled it with water, you would find that the glass containing the water weighed the most. Another name to give to this difference would be to say that the water was more dense than the wood. By the law of gravitation the denser thing will always go to the bottom, and as wood is less dense than water, it will stay at the top if put in water. The piece of wood has more air in it than the water. If you could expel the air from the piece of wood and then put it in water, it would sink.

Why Does Iron Sink In Water?

The explanation in regard to the piece of wood floating in water is the beginning of the answer to this question. A piece of iron is heavier than an equal bulk of water, and will therefore go to the bottom, as will all things which are more dense than water. A piece of iron has no air in it. The particles of a piece of iron are so close together that there is no room for air in it and it will therefore sink in water. A piece of wood from which all of the air had been expelled would also sink.

Why Doesn’t an Iron Ship Sink?

This is a very natural question for you to ask right after you were told why iron sinks in water. The explanation is that by making an iron ship in the way we do, we fix it so that it holds a lot of air in between the bottom and sides, making the combination of the two--the iron ship and the air in it--lighter than the water on which it sails. Men thought at one time that a ship would sink if made of iron, and therefore built all of their ships of wood. Finally one inventor made a ship of iron and it was one of the wonders of the world. When we found that iron ships would float if they were built to retain sufficient air to keep them from sinking, we made the hulls of most ships of iron for a time. Now, however, the best ships are made of steel, which is even better.

If you bore a hole in the bottom of a ship, the water will run in if the ship is in the water, and the ship will sink, because the water coming in drives out the air; and when the ship is full of water, the water in it, with the ship itself, are heavier than the water on which it sails, and the ship will go down. Filling a ship with water makes the iron part of the ship just like a bar of iron, so far as its sinking qualities are concerned.

Of course, an iron ship must be made long enough and broad enough so that when it is completed there will be sufficient air contained within the hull to make the combination lighter than water. Always, therefore, when a ship is to be built, competent engineers must go over the plans of the vessel and calculate the air capacity, so as to make sure she will float.

Nowadays it would be difficult to sink a modern vessel by boring one small hole in the bottom, because the bottom and sides are lined with enclosed steel air-chambers, and a ship will keep afloat even if one or a number of holes are made. The reason is, of course, that when you bore a hole into one of these air-chambers the water rushing in will fill that air-chamber with water, but as there is no connection from the inside with the rest of the ship, the water can get no further.

Why Does a Poker Get Hot at Both Ends if Left in the Fire?

Both ends of the poker become heated because the poker is made of iron, and iron is a particularly good conductor of heat. To understand this we must look into the question of what a good conductor of heat is. In this case the particles of iron, which combined form the poker, are so close together that when those at the end of the poker which is in the fire get hot, the particles at that end hand the heat on to the particles next to them, and so on until the whole poker is hot. The difference between a thing which is a good conductor of heat and a thing which is not a good conductor, lies in the ability of the different particles which compose it to hand the heat on to the others. Did you ever notice that the handle of a solid silver spoon will become hot if the spoon is left in hot coffee? Solid silver is a good conductor of heat. A plated spoon is not a good conductor, however, and will not become hot if left in the cup of hot coffee as a solid silver spoon will.

Would a Wooden Spoon Get Hot?

A wooden spoon would not get hot, because wood is not a good conductor of heat. The atoms which compose the wood have not the power to transmit the heat to each other. This is strange, too, when we think that a poker is a good conductor of heat, but will not burn, while wood is not a good conductor, but will burn readily. Perhaps you have already discovered this in connection with a wood fire. One end of a stick of wood may be burning fiercely, and yet you can pick it up by the other end and find it is not even warm. This proves to you that wood is not a good conductor of heat, and explains why the handle of a wooden spoon in a bowl of hot soup will not get hot while the handle of a silver spoon will.

Why Does Iron Turn Red When Red Hot?

The answer is that the piece of iron has been heated to the point where it gives off light of its own. The red you see is only one stage in the development of iron to the point where it makes its own light. If you heat it still more it will make a white light. You know that it produces the light itself, because if you take a piece of iron into a perfectly dark room and heat it to a white heat it will show better than where there is other light. If you continue the process the iron will melt and change in form. Therefore, the “red hot” name for a piece of iron in that state is a perfect name. It is a warning that the iron is coming to a point where if the heating process is continued, it will change its form and in this state, when treated according to known methods, the iron is turned into steel, which has many characteristics that iron does not possess. Now, I can, of course, hear you ask why doesn’t an iron kettle get red hot? and I can answer that easily. If you treat the kettle the same way as you do the piece of iron, it will get red hot. The difference is that you are thinking of an iron kettle with water in it. As long as there is any water in the kettle, that keeps it from getting hot. The water inside keeps the kettle from becoming red hot. If you took a hollow rod of iron and filled it with water, it would not become red hot as long as any water remained in the hollow portion.

How Did the Sand Get on the Seashore?

The sand on the seashore is nothing more or less than ground-up sandstone. In dealing with the inanimate things in the world we find that a very important element of all of them has been given the name silicon. When the crust of the earth, which is the part we call the land and rocks, and includes the part under the sea, was a molten mass, this silicon was burned, combining with the oxygen which surrounded everything, and produced what is known as silica. Silica is the name given to the thing which is left after you burn silicon. A very large part of this silica was deposited in parts of the earth, and when the crust of the earth cooled off it was sand. By pressure and contact with other substances it became stuck together, just as you can take wet sand at the seashore to-day and make bricks and houses and tunnels, excepting that in the case we speak of it was something besides water that pressed and stuck the little particles of sand together. They stuck together more permanently. Then when the oceans were formed, as shown in another part of this book, much of the sandstone was found to be at the bottom and on the shores of the oceans. The action of the water continually washing against the sandstone gradually broke the sandstone up into the tiny particles of sand again, and this is what makes the sand on the seashore.

What Makes a Soap Bubble?

A bubble is merely a hollow ball of water with air inside. The air in coming up through the water in trying to rise out of the water is caught in the water in such a way as to form the bubble, and since the ability of the air inside of the bubble to rise is greater than that of the water which forms the bubble, and which has a tendency to pull it down, the bubble rises into the air. The water ball is very thin and keeps running down to the bottom of the ball, where you see it form into drops, and soon this makes the walls of the water bubble so thin that the air bursts through the ball of water, and that is

What Makes the Bubble Explode?

Sometimes we blow soap bubbles. We mix soap in the water and that makes the walls of the water ball which we produce a little tougher, and it requires a great deal more effort for the air to escape from it, as the soap keeps the water in the walls of the bubble from running down to the bottom for quite some time, and, therefore, soap bubbles will often travel in the air for some distance. The colors we see on soap bubbles are produced by the rays of sunlight, which strike the bubble and reflect them back to us in colors very similar to those of the rainbow.

Why Are Bubbles Round?

Bubbles are round because the air which forms the inside of the bubble exerts an equal pressure in all directions. It presses equally against all sides of the bubble at the same time.

The Story in a Yard of Silk

God’s Creation and Man’s Invention.

~WHERE DOES SILK COME FROM?~

Silk in its finished state is an ideal product. It is at once durable, magnificent to the eye, tender to the touch, and its rustle is soft music to the ear. Hence it is easy to understand why the silkworm, from the earliest times, has been an object of much consideration and concern from a commercial and industrial point of view. In this country alone, we annually expend as much for silk goods as we do for public education and thirty times as much as we do for foreign missions. Such an indomitable producer of wealth is the silkworm, and a producer of wealth it has been from an age as remote as when Joseph was down in old Egypt, interpreting the dreams of King Pharaoh’s butler and baker and later that of the King himself.

To-day we speak of twenty centuries, and our minds can hardly comprehend such a lapse of time. What shall we think of the silkworm, that for twice twenty centuries has furnished practically all the raw material for the world’s silk supply? Because man’s ingenuity is at present actively engaged in the attempt to displace it by cheaper substitutes, the thought has come to us that, without going too minutely into mechanical processes, a good opportunity is presented to give some interesting information in regard to the silkworm as the creation of the Divine Hand, in contrast to the silkworm as the creation of man.

According to Chinese authority, the use of silk dates from 2650 B.C., and it is generally conceded that, in point of age, it stands midway among the great textiles, wool and cotton having preceded it, while flax, hemp and other fibrous plants followed shortly in its train.

The first patron of the silkworm was Hoang-Ti, Third Emperor of China, and his Empress, Si-Ling-Chi, was the first practical silkworm breeder and silk reeler. It is related of her that she was once walking in the palace gardens when she discovered a strange and repulsive looking worm. It was small, of a pale green color, and was feeding greedily on a mulberry leaf. She interested the Emperor in this strange creature, and, at the Emperor’s suggestion, took the fine silken web which the worm finally spun, and was the first to successfully reel the new filament and weave it into cloth. So beneficial to the nation was her work considered that her gratified subjects bestowed upon her the divine title of “Goddess of the Silkworms,” and to this day the Chinese celebrate in her honor the “Con-Con Feast,” which takes place during the season in which the silkworm eggs are hatched.

In accounting for the presence of silkworms in the garden of this early empress, we can rightly conclude that certain parts of China have always abounded in forests of mulberry trees, and that the worms themselves had existed in great numbers in a wild state and attached their cocoons to the trees for ages before any use was discovered for their web. In fact, such wild silkworms not only abound in China to-day, but have also been found in Southern and Eastern Asia, inhabiting the jungles of India, Pegu, Siam and Cochin China, but the cocoons of these worms are, naturally, of a very inferior quality, and are only used for the crudest kind of work.

Illustration by courtesy The Brainerd & Armstrong Silk Co.

THE INTRODUCTION OF SILK INTO EUROPE

Pilgrims brought silkworm eggs in their staffs, together with the branches of mulberry trees, from China to the Court of Justinian at Byzantine, A.D. 555. The penalty for taking silkworm eggs out of China was death.

The accompanying illustration is a reproduction of a mural painting on rep in the Royal Textile Museum at Crefeld, Germany, one of the great silk textile centers of the world. The artist shows the pilgrims presenting the silkworm eggs and the mulberry branches to Justinian, beside whom, just in the act of rising, is his famous queen Theodora.]

Silk culture from the time of Hoang-Ti became one of the cherished secrets of China. The headquarters of the industry was in the Province of Chen Tong, where was produced the silk for the royal family. In time the silk and stuffs of China became articles of export to various portions of Asia. Long journeys were made by caravans, occupying two-thirds of a year in going from the cities of China to those of Syria, but the price obtained there exceeded the expense of the journey, and thus left a large margin of profit to the merchants. In this manner, for one thousand years, the Chinese sent their silk to the Persians who, without knowing how or from what it was made, carried it to the Western nations.

So carefully did the Orientals guard their secret, that there is reason to believe that Aristotle was the first person in the occidental world to learn the true origin of the wrought silk from Persia. In commenting on the silk which was brought from that country on the return of Alexander’s victorious army, he described the silkworm as a “horned insect,” passing through several transformations, which produced “bomby-kia,” as he called the silk. But the classics must convince one that Aristotle’s discovery did not at once become matter of current knowledge. In fact, for five hundred years after Aristotle’s time the common theory of the origin of silk among the Greeks and Romans was that it was either “a fleece which grew upon a tree” (thus confounding it with cotton), or a fibre obtained from the inner bark of a tree; and some, deceived by the glossy and silky fibres of the seed vessels of the plant that corresponds to our milk or silk weed, believed it to be the product of some plant or flower. So Virgil, in speaking of silk, says, “the Seres comb the delicate fleecings from the leaves.”

In the Sixth Century, A.D., all the raw silk was still being imported from China by way of Persia, when the Emperor Justinian, having engaged in war with Persia, found his supply of raw silk cut off and the manufacturers in great distress. His foolish legislation did not help the situation, and a crisis was averted only by two Nestorian monks, who came from China with seed of the mulberry tree and a knowledge of the Chinese method of rearing worms. No one, on pain of death, was allowed to export the silkworm eggs from China, but Justinian bribed the monks to return to that country, and in 555 they came back, bringing with them a quantity of silkworm eggs concealed in their pilgrim’s staffs. And here let us say that there has only once since been an important importation of eggs from Asia. That was about 1860, when Dr. Pasteur was making a study of a germ disease which was threatening the industry. Consequently, it can truly be said that practically all the silkworms of the Western world are descended from those brought in the eggs by the monks to Constantinople. Justinian gave the control of the silk industry to his own treasurer. Weavers, brought from Tyre and Berytus, were employed to manufacture the silk, and the whole production was a monopoly of the emperor, he fixing its prices. Under his management, the cost of silk became eight times as great as before, and the Royal Purple was twenty-four times its former price. But this monopoly was not of long duration and, at the death of Justinian in 565, the monopoly ceased, and the spread of the industry commenced in new and diverse directions.

While every detail of the growth of the industry has an unusual interest, as showing how such an insignificant thing as a worm may become a potent factor in Nature’s economy, the scope of this article will hardly allow us to more than sketch some of the other more salient points of the history of the silkworm.

About the year 910, the silkworms made their appearance in Cordova, Spain, being brought there by the Moors. From Spain silk culture soon extended to Greece and Italy.

~WHEN SILK CULTURE WAS INTRODUCED IN AMERICA~

Silk was introduced on this continent through the Spanish Conquest of Mexico, and the first silkworm eggs sold for $60.00 an ounce.

A century later royal orders were issued requiring mulberry trees to be planted in the Colony of Virginia, and a fine of twenty pounds of tobacco was imposed for neglect, and fifty pounds of tobacco was given as a bounty for every pound of reeled silk produced.

Silk culture spread rapidly in the other Colonies, and to-day the story of the ineffectual attempts to profitably rear the silkworm in this country is as voluminous as it is interesting. Suffice it to say, as a sop to our inherent Yankee pride, that silk culture was introduced into Connecticut as early as 1737, the first coat and stockings made from New England silk being worn by Governor Law in 1747, and the first silk dress by his daughter, in 1750. This State, for the eighty-four years following, led all the others in the amount of raw silk produced. In Connecticut also, was built the first silk mill to be erected on this continent for the special purpose of manufacturing silk goods. This building was constructed in 1810 by Rodney and Horatio Hanks, at Mansfield, and is still standing as an heirloom which has come to us from the infant days of the industry.

The silkworm has become domesticated, since, during the long centuries in which it has been cultivated, it has acquired many useful peculiarities. Man has striven to increase its silk producing power, and in this he has succeeded, for, by comparing the cocoon of the silkworm of to-day with its wild relations, the cocoon is found to be much larger, even in proportion to the size of the worm that makes it or the moth that issues from it. The moth’s loss of the power of flight and the white color of the species are probably the results of domestication.

GATHERING MULBERRY BRANCHES.[1]

This picture shows a grove of mulberry trees from which branches are being gathered as food for the worms. This is often done by the children.]

The moths are placed upon pieces of cardboard, upon which they deposit their eggs.

The cards with the eggs are kept in a cool place until the season for hatching arrives.]

This picture shows two boys preparing a bed of twigs or branches upon which the worms may spin their cocoons.]

[1] Illustrations by courtesy The Brainerd & Armstrong Co.

HATCHING THE EGGS.

As the eggs hatch on the cards, the young worms are removed to other cards or trays, where they are fed and cared for.]

Every few days the young worms are changed to new and clean cards.]

The cocoons are soaked in hot water in the basins shown in the front to loosen the gum. The silk threads then pass through the hands of the operators and are reeled on swifts in the cabinet shown in the rear.

A more modern appliance for reeling the silk is shown on one of the following pages.]

The foregoing pages and pictures by courtesy of Brainerd & Armstrong
Silk Company, from their book entitled, “Silk, the Real versus the
Imitation.”

]

]

]

]

]

[2] The cuts on this page and balance of cuts in the story of silk
copyright by the Corticelli Silk Mills.

The silk moth exists in four states--egg, larva, chrysalis, and adult. The egg of the moth is nearly round, slightly flattened, and closely resembles a turnip seed. When first laid it is yellow, soon turning a gray or slate color if impregnated. It has a small spot on one end called the micropyle, and when the worm hatches, which in our climate is about the first of June, it gnaws a hole through this spot. Black in color, scarcely an eighth of an inch in length, covered with long hair, with a shiny nose, and sixteen small legs, the baby worm is born, leaving the shell of the egg white and transparent.

~THE SILKWORM—HOW HE DOES HIS WORK~

Small and tender leaves of the white mulberry or osage orange are fed the young worm which simply pierces them and sucks the sap. Soon the worm becomes large enough to eat the tender portions between the veins of the leaf. In eating they hold the leaves by the six forward feet, and then cut off semi-circular slices from the leaf’s edge by the sharp upper portion of the mouth. The jaws move sidewise, and several thousand worms eating make a noise like falling rain.

The worms are kept on trays made of matting, that are placed on racks for convenience in handling. The leaves are placed beside the worms, or upon a slatted or perforated tray placed above them, and those that crawl off are retained, while the weak ones are removed with the old leaves. The worms breathe through spiracles, small holes which look like black spots, one row of nine down each side of the body. They have no eyes, but are quite sensitive to a jar, and if you hit the rack they stop eating and throw their heads to one side. They are velvety, smooth, and cold to the touch, and the flesh is firm, almost hard. The pulsation of the blood may be traced on the back of the worm, running towards the head.

The worm has four molting seasons, at each of which it sheds its old skin for a new one, since in the very rapid growth of the worm the old skin cannot keep pace with the growth of the body. The periods between these different molts are called “ages,” there being five, the first extending from the time of hatching to the end of the first molt, and the last from the end of the fourth molt to the transformation of the insect into a chrysalis. The time between the four “molts” will be found to vary, depending upon the species of worm.

]

When the worm molts it ceases eating, grows slightly lighter in color, fastens itself firmly by the ten prolegs, and especially by the last two, to some object, and holding up its head and the fore part of its body remains in a torpid state for nearly two days.

By each successive molt the worm grows lighter, finally becoming a slate or cream white color, and the hair, which was long at first, gradually disappears. The gummy liquid which combines the two strands hardens immediately on exposure to the air.

The worm works incessantly, forcing the silk out by the contraction of its body. The thin, gauze-like network which soon surrounds it gradually thickens, until, twenty-four hours after beginning to spin, the worm is nearly hidden from view. However, the cocoon is not completed for about three days.

~SIXTY-FIVE MOTIONS OF HIS HEAD A MINUTE~

The cocoon is tough, strong, and compact, composed of a firm, continuous thread, which is, however, not wound in concentric circles, but irregularly in short figure eight loops, first in one place and then in another. In doing this the worm makes sixty-five elliptical motions of his head a minute or a total of 300,000 in an average cocoon. The motion of the worm’s head when starting the cocoon is very rapid, and nine to twelve inches of silk flow from the spinneret in a minute, but later the average would be about half this amount per minute.

]

SILKWORM PREPARING TO FORM ITS COCOON.]

Having attained full growth, the worm is ready to spin its cocoon. It loses its appetite, shrinks nearly an inch in length, grows nearly transparent, often acquiring a pinkish hue, becomes restless, seeks a quiet place or corner, and moves its head from side to side in an effort to find objects on which to attach its guy lines within which to build its cocoon. The silk is elaborated in a semi-fluid condition in two long, convoluted vessels or glands between the prolegs and head, one upon each side of the alimentary canal. As these vessels approach the head they grow more slender, and finally unite within the spinneret, a small double orifice below the mouth, from which the silk issues in a glutinous state and apparently in a single thread.

The color of the worm’s prolegs before spinning indicates the color the cocoon will be. This varies in different species, and may be a silvery white, cream, yellow, lemon, or green.

~WHEN THE SILKWORM’S WORK IS DONE~

When the worm has finished spinning, it is one and a quarter inches long. Two days later, by a final molt, its dried-up skin breaks at the nose and is crowded back off the body, revealing the chrysalis, an oval cone one inch in length. It is a light yellow in color, and immediately after molting is soft to the touch. The ten prolegs of the worm have disappeared, the four wings of the future moth are folded over the breast, together with the six legs and two feelers, or antennæ. It soon turns brown, and the skin hardens into a tough shell. Nature provides the cocoon to protect the worm from the elements while it is being transformed into a chrysalis, and thence into the moth.

With no jaws, and confined within the narrow space of the cocoon, the moth has some difficulty in escaping. After two or three weeks the shell of the chrysalis bursts, and the moth ejects against the end of the cocoon a strongly alkaline liquid which moistens and dissolves the hard, gummy lining. Pushing aside some of the silken threads and breaking others, with crimped and damp wings the moth emerges; and the exit once effected, the wings soon expand and dry.

The escape of the moth, however, breaks so many threads that the cocoons are ruined for reeling, and consequently, when ten days old, all those not intended for seed are placed in a steam heater to stifle the chrysalis, and the silk may then be reeled at any future time.

The moths are cream white in color. They have no mouths, but do have eyes, which is just the reverse of the case of the worm. From the time it begins to spin until the moth dies, the insect takes no nourishment. The six forward legs of the worm become the legs of the moth. Soon after mating the eggs are laid.

The male has broader feelers than the female, is smaller in size, and quite active. The female lays half her eggs, rests a few hours, and then lays the remainder. Her two or three days’ life is spent within a space occupying less than six inches in diameter.

One moth lays from three to four hundred eggs, depositing them over an even surface. In some species a gummy liquid sticks the eggs to the object upon which they are laid. In the large cocoon varieties there are full thirty thousand eggs in a single ounce avoirdupois. It takes from twenty-five hundred to three thousand cocoons to make a pound of reeled silk. Do you wonder that, centuries ago, silk was valued at its weight in gold?

Growers of silk in the United States, by working early and late every day during the season, which lasts from six to eight weeks, could scarcely average fifteen cents for a day’s labor of ten hours. Silk, once regarded as a luxury, is now considered a necessity.

REELING THE SILK FROM COCOONS BY FOOT POWER, CALLED “RE-REEL” SILK.

The cocoons are first assorted, those of the same color being placed by themselves, and those of fine and coarse texture likewise. The outside loose silk is then removed, as this cannot be reeled, after which the cocoons are plunged into warm water to soften the “gum” which sticks the threads together. The operator brushes the cocoons with a small broom, to the straws of which their fibers become attached, and then carefully unwinds the loose silk until each cocoon shows but one thread. These three operations are called “soaking,” “brushing,” and “cleansing.”

Into one or two compartments in a basin of warm water below the reel are placed four or more cocoons, according to the size of the thread desired. The threads from the cocoons in each compartment are gathered together and, after passing through two separate perforated agates a few inches above the surface of the water, are brought together and twisted around each other several times, then separated and passed upward over the traverse guide-eyes to the reel. The traverse moves to and fro horizontally, distributing the thread in a broad band over the surface of the reel. The rapid crossing of the thread from side to side of the skein in reeling facilitates handling and unwinding without tangling, the natural gum of the silk sticking the threads to each other on the arms of the reel, thus securing the traverse. Silk reeled by hand or foot power is known as “Re-reel” silk, while silk reeled by power machinery is called “Filature.”]

]

WINDING FRAMES--WINDING THE SILK ON BOBBINS.]

~WHERE MAN’S WORK ON THE SILK BEGINS~

The raw silk is first assorted, according to the size of the fiber, as fine, medium, and coarse. The skeins are put into canvas bags and then soaked over night in warm soapsuds. This is necessary to soften the natural gum in the silk, which had stuck the threads together on the arms of the reel. Following the soaking, the skeins are straightened out and hung across poles in a steam-heated room, as shown in the accompanying photograph. When the skeins are dry, they are ready for the first process of manufacturing. The room we now step into is filled with “winding frames,” each containing two long rows of “swifts,” from which the silk is wound on to bobbins. The bobbins are large spools about three inches long. The bobbins filled with silk, as wound from the skeins, are next placed on pins of the “doubling frames”; the thread from several bobbins, according to the size of the silk desired, is passed upward through drop wires on to another bobbin. Should one of the threads break, the “drop wire” falls, which action stops the bobbin. By this ingenious device absolute uniformity in the size of silk is secured. The “doubling frame” is shown in one of the photographs herewith.

The bobbins taken from the “doubling frame” are next placed on a “spinner.” Driven by an endless belt at the rate of over six thousand turns a minute, the bobbins revolve, the silk from them being drawn upward on to another bobbin. This spins the several strands brought together by the “doubling process” into one thread, the number of turns depending on the kind of silk--Filo silk being spun quite slack, and Machine Twist just the reverse.

]

]

A transferring machine combines two or three of these strands; two for sewing silk and three for machine twist; and the bobbin next goes on to the “twisting machine”--a machine that is similar to a “spinner,” but the silk is twisted in the opposite direction from the spinning. To stand before these machines and watch how rapidly and how accurately they do the work assigned them is a revelation. No one realizes how nicely the parts are adjusted. If but one tiny strand breaks that part of the machinery is stopped by an automatic device which works instantaneously. After twisting, the silk is stretched by an ingenious machine called a “water-stretcher.” This smooths and consolidates the constituent fibers, giving an evenness to the silk not to be obtained by any other known process. The bobbins are placed in water and the silk is wound on to the lower of the two copper rolls. From the lower roll it passes upward to the upper roll, which turns faster than the lower one, thereby stretching the silk. From the upper roll it passes again on to a bobbin.

WATER STRETCHER--MAKING THE SILK THREAD SMOOTH.]

The dyeing process is a very important one, and upon its success depends the permanency of the various colors.

Vast tubs, tanks, and kettles surround you on every side, and the hissing steam seems to spring from all quarters. The “gum” of the silk is first boiled out by immersion in strong soapsuds for about four hours. The attendants, standing in heavy “clogs” (big shoes with wooden soles two inches thick), turn the silk on the sticks at intervals until the gum is removed. After the silk is dyed it is put into a “steam finisher,” a device looking like a long, narrow box with a cover opening on the side, set upright on top of an iron cylinder. The hanks of silk are placed upon two pins in the steam chest, the cover fastened, and the live steam rushes in around the silk. This brightens the silk, giving it the lustrous, glossy appearance.

The editors are indebted to the Corticelli Silk Mills, Florence,
Mass., for this story of how silk is made, as well as for permission
to use their splendid life-like copyrighted photographs of the
silkworm. Many teachers will be glad to know that they can obtain
from the Corticelli Silk Mills, at slight expense, specimen cocoons
and other helps for object lesson teaching.

What Animal Can Leap the Greatest Distance?

The galago, or flying lemur. This singular animal is a native of the Indian Archipelago. It is from 2 ft. to 3 ft. in length, and is furnished with a sort of membrane on each side of its body connecting its limbs with each other; this is extended and acts as a parachute while taking its long leaps, which measure about 300 ft. in an inclined plane. The kangaroo can leap with ease a distance of between 60 ft. and 70 ft. and can spring clean over a horse and take fences from 12 ft. to 14 ft. in height. The animals that can leap the greatest distance in proportion to their size are the flea and the grasshopper, the former being able to leap over an obstacle five hundred times its own height, while the grasshopper can leap for a distance measuring 200 times its own length. The springbok will clear from 30 ft. to 40 ft. at a single bound. The flying squirrel, in leaping from tree to tree often clears 50 ft. in a leap. This animal also has a broad fold of skin or membrane connecting its fore and hind legs. A steeplechase horse, called The Chandler, is reported to have covered 39 ft. in a single leap at Warwick some years ago. Some species of antelopes can make a leap 36 ft. in length and 10 ft. in height. A lion and a tiger each clear from 18 ft. to over 20 ft. at a bound while springing on their prey. A salmon often leaps 15 ft. out of the water in ascending the falls of rivers.

Why Do We Call Voting Balloting?

The term covers all forms of secret voting, as in early times such votes were determined by balls of different colors deposited in the same box, or balls of one color placed in various boxes. The Greeks used shells (ostrakon), whence we derive the term ostracism. In 139 B.C. the Romans voted by tickets. The ballot was first used in America in 1629, when the Salem Church thus chose a pastor. It was employed in the Netherlands in the same year, but was not established in England until 1872, although in Scotland it was used in cases of ostracism in the 17th century. In 1634 the governor of Massachusetts was elected by ballot, and the constitutions of Pennsylvania, New Jersey and North Carolina adopted in 1776, made this method of voting obligatory. The ballot progressed slowly in the Southern States, Kentucky retaining the viva voce method until a comparatively recent date. In certain states, the constitutions stipulate that the legislature shall vote viva voce, i. e., cast their votes orally. Since 1875 all congressmen have been elected by ballot. In 1888 the Australian ballot system, which requires the names of all the candidates for the various offices to be placed on one large sheet of paper, commonly known as a “blanket” ticket, was adopted in Louisville, Ky., and some sections of Massachusetts. It is now in very general use in this country. The voter, in the privacy of an individual booth, indicates his preference by making a mark opposite a party emblem or a candidate’s name. This system originated in 1851 with Francis S. Dutton, of South Australia, and Henry George, in a pamphlet, “English Elections,” published in 1882, was the first to advocate it in the United States. The first bill enacting it into a law here was introduced in the Michigan legislature in 1887, but it did not pass until 1889.

Why Do We Call a Cab a Hansom?