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diff --git a/75948-0.txt b/75948-0.txt new file mode 100644 index 0000000..867a625 --- /dev/null +++ b/75948-0.txt @@ -0,0 +1,30917 @@ + +*** START OF THE PROJECT GUTENBERG EBOOK 75948 *** + + + + Transcriber’s Notes + + Words, letters and phrases printed in boldface or italics in the + source document have been transcribed between =equal signs= and + _underscores_ respectively. Small capitals have been transcribed + as ALL CAPITALS. Phrases between ~tildes~ represent side notes. ^o + stands for a superscript o. + + More Transcriber’s Notes may be found at the end of this text. + + + + + THE + BOOK OF WONDERS + + +[Illustration: HOW MAN BURROWS UNDER THE WATER + +This is a picture of a section of one of the world’s greatest tunnels, +showing how man has learned to construct great tubes of steel beneath +the surface of the water and land, in which to run the swiftly moving +trains which carry him rapidly from place to place.] + + + + + THE + BOOK OF WONDERS + + GIVES PLAIN AND SIMPLE ANSWERS TO THE + THOUSANDS OF EVERYDAY QUESTIONS + THAT ARE ASKED AND WHICH ALL SHOULD + BE ABLE TO, BUT CANNOT ANSWER + + FULLY ILLUSTRATED WITH HUNDREDS OF EDUCATIONAL PICTURES + WHICH STIMULATE THE MIND AND GIVE A + BIRD’S EYE VIEW OF THE + + WONDERS OF NATURE + and the + WONDERS PRODUCED BY MAN + + Edited and Arranged by + RUDOLPH J. BODMER + + + Fully Indexed + + 1915 + PRESBREY SYNDICATE, INC. + 456 Fourth Avenue + NEW YORK + + + + + Copyright, 1914 + BY + PRESBREY SYNDICATE, Inc. + + + + +Introduction + + +No truly great book needs an explanation of its aim and purpose. A +great book just grows, as has this Book of Wonders. + +It began with the attempt of a father to answer the natural questions +of the active mind of a growing boy. It developed into a nightly search +for plain, understandable answers to such questions as “What makes +it night?” “Where does the wind begin?” “Why is the sky blue?” “Why +does it hurt when I cut my finger?” “Why doesn’t it hurt when I cut my +hair?” “Why does wood float?” “Why does iron sink?” “Why doesn’t an +iron ship sink?” on through the maze of thousands of puzzling questions +which occur to the child’s mind. It has grown until the answers to +the mere questions cover practically the entire range of every-day +knowledge, and has been arranged in such a form that any child may now +find the answer to his own inquiries. + +As the mind of the child matures, the questions naturally drift toward +the things which the genius of man has provided for his comfort and +pleasure. We have become so accustomed to the use and benefits of these +wonders produced by man that we generally leave out of our books the +stories of our great industries, and yet the mind of the child wonders +and inquires about them. We have so long worn clothes made of wool or +cotton, that we have forgotten the wonder there is in making a bolt +of cloth. Every industry has a fascinating story equal to that of the +silkworm, which moves its head sixty-five times a minute while spinning +his thousand yards of silk. + +Can you tell What happens when we telephone? How a telegram gets +there? What makes an automobile go? How man learned to tell time? How +a moving-picture is made? How a camera takes a picture? How rope is +made? How the light gets into the electric bulb? How glass is made? +How the music gets into the piano? and hundreds of others that embrace +the captivating tales of how man has made use of the wonders of nature +and turned them to his advantage and comfort? The Book of Wonders does +this with illuminating pictures which stimulate the mind and give a +bird’s-eye view of each subject step by step. + +Where shall such a book begin? Shall it begin with the Story of How +Man Learned to Light a Fire--he could not cook his food, see at night, +or keep warm without a fire; or should it begin with How Man Learned to +Shoot--he could not protect himself against the beasts of the forest, +and, therefore, could not move about, till the soil or obtain food to +cook until he knew how to shoot or destroy. + +What was the vital thing for man to know before he could really become +civilized? Some means, of course, by which the things he learned--the +knowledge he had acquired--could be handed down to those who came after +him so that they might go on with the intelligence handed down to them. +This required some means of recording his knowledge. Man had to learn +to write. Without writing there could be no Book of Wonders, and the +book, then, begins naturally with the Story of Mow Man Learned to Write. + + THE EDITOR. + +[Illustration: WRITING BY MEXICAN INDIANS THOUGHT TO BE MORE THAN TEN +THOUSAND YEARS OLD.] + + + + +How Man Learned to Write + + +It is a long time between the day of the cave-dwellers, with their +instruments of chipped stone, and the present day of the pen. Yet wide +apart as are these points of time, the trend of development can with +but few obstacles be traced. + +The story of the pen is a natural sequence of ideas between the first +piece of rock scratched upon rock by prehistoric man, and the bit of +metal which now so smoothly records our thoughts. + +There was a time in the unwritten history of man when necessity +prompted the invention of weapons, and the minds of these primitive men +were concentrated upon this point. But the arts of war did not take up +their entire time; some time must have been given to other pursuits. +As the mind developed, and as an aid to memory, we find them carving, +engraving, incising upon the rocks their hieroglyphics, which took the +form of figures of men, habitations, weapons, and the animals of their +period. + +[Illustration: THE STYLUS] + + +How Did Writing First Come About? + +An apparently difficult question to answer, since without writing there +can be no record of its origin, and without records no facts; yet the +deduction is so clear that the answer is simple. Somewhere far, far +back in the dawn of the world, back in the beginning of human history, +in the epoch which we have now named the Quaternary Period, man lived +in a dense wilderness surrounded by the wildest and most ferocious +beasts. His home was a cave, exposed to the dangers incidental to that +time and his surroundings, and he was of necessity compelled to look +about for means of defense. With this idea in mind, he found that by +striking one stone against another he knocked off chips, which chips +could be used as arrow-heads, spears and axes. Following along these +lines he discovered that by rubbing one of these chips against another +there was left a mark, which was the first imitation of writing; that +the sharper the edge of the chip, the deeper was the scratch, and +consequently the more distinct the mark. + +[Illustration: EARLIEST WAYS OF WRITING + +THE FIRST IMITATION OF WRITING] + +Next it was discovered that certain stones, such as flint, serpentine +and chalcedony, marked more readily than others; that the elongated +chip was handled with more facility; that by rubbing one stone against +another the finest possible points and edges might be obtained. Thus in +the Age of Stone was the long, tapering instrument of stone, the first +pen, the Stylus, originated. + +Then came the time, known as the Bronze Age, when men learned to +hammer metal into shapes, and metal having many advantages over stone, +the stylus of stone gave way to one of iron. So we find that in the +time of the Egyptians, about fourteen or fifteen centuries B.C., an +iron stylus was in use for marking on soapstone, limestone and waxed +surfaces. An improvement in this metal stylus was that the blunt end +was convex and smooth, the purpose of which was to erase and smooth +over irregularities. In some cases it was pointed with diamonds, which +gave it greater cutting properties. The iron stylus was also used by +the Egyptians of that period, as well as in later times, with a mallet, +after the manner of the modern chisel (which indeed it resembled) for +cutting out inscriptions on their monuments. + +[Illustration: THE BRUSH] + +~WRITING FLUIDS HELPED DEVELOPMENT~ + +In course of time a marking fluid was discovered, and this made +necessary a writing instrument which could spread characters on +parchment, tree-bark, etc. Thus it was found that by putting together +a small bunch of hairs, arranging them in the shape of an acute cone, +and fastening them together in some manner, an instrument could be +made which would carry fluid in its path, and thus make a mark of the +desired shape. The hair best adapted for the purpose was found to be +camel’s hair, while that of the badger and sable was also used. A tube +cut from a stalk of grass answered for a holder. The hairs were held +together by a piece of thread which was then drawn through the tube, +thus making the first writing instrument to be used in conjunction with +ink, the Brush. + +[Illustration: HOW THE CHINESE IMPROVED METHODS] + +Just when the Brush came into existence is not definitely known, but +with this instrument the great Chinese philosopher Confucius wrote his +marvelous philosophy. The Brush as a writing instrument is generally +associated with the Chinese, because the Chinese use this instrument +even to the present day, it being especially adapted to their letters +and mode of writing. We have now a pen (brush), as well as an ink, but +the material upon which the people of that age wrote, in lieu of paper, +was still very crude, parchment and tree-bark being most commonly used. + +[Illustration: THE QUILL] + +~THE EARLIEST FORMS OF PAPER~ + +Just as the discovery of an ink wrought a change from the Stylus to +the Brush, so the advent of papyrus, a paper made from the papyrus +plant, which was much finer and more economical than parchment, brought +with it a pen better adapted for this material. It was found that +the Reed, or Calamo, as it was called, which grew on the marshes on +the shores of Egypt, Armenia and the Persian Gulf, if cut into short +lengths and trimmed down to a point, made an admirable pen for this +newly discovered paper. This was the true ancient representative and +precursor of the modern pen. The use of the Reed can be traced to a +remote antiquity among the civilized nations of the East, where Reeds +are in use now as instruments for writing. + +[Illustration: HOW THE MONKS DID THEIR WRITING] + +The introduction of a finer paper rendered necessary a finer instrument +of writing, and the quill of the goose, swan, and, for very fine +writing, of the crow, was found to be well adapted. Immense flocks of +geese were raised, chiefly for their quills. The earliest specific +allusion to the quill occurs in the writings of St. Isadore de Seville, +seventh century, although it is believed to have been in use at an +earlier period. The quill was used for many centuries. Most of the +writing during its reign was done in the monasteries by the monks, and +in the eighteenth century, when quill-making became quite an art, +every monk and every teacher was expected to be proficient in the art +of making a pen from a quill. The preliminary process of preparing the +quills was first to sort them according to their quality, dry in the +hot sand, then clean them of the outer skin, and harden by dipping in +a boiling solution of alum and diluted nitric acid. During the last +century many efforts were made to improve the quill, its great defect +being speedy injury from use. Ruby points were fitted to the nib, but +this was found impracticable on account of the delicacy of the work. +Joseph Bramah devised, in 1809, a machine for cutting the quill into +separate nibs for use in holders, thus making several pens from one +quill and anticipating the form of the modern pen. + +[Illustration: THE STEEL TUBE PEN] + +[Illustration: THE FIRST STEEL PEN] + +The quill held sway as writing instrument for many years, and with +it the greatest masterpieces in literature have been written. Many +attempts, however, had been made to supersede the quill by a pen not so +easily injured by use, but it was not until about 1780 that, after much +experimenting and numerous failures, Mr. Samuel Harrison introduced the +first metallic pen. + +~THE INVENTION OF THE PEN~ + +This pen was made as follows: + +A sheet of steel was rolled in the form of a tube. One end was cut and +trimmed to a point after the manner of the quill, the seam where both +edges of the tube met forming the slit of the pen. This was soon after +improved upon by cutting a rough blank out of a thin sheet of steel, +which blank was filed into form about the nib, rounded, and with a +sharp chisel marked inside where the slit was to be in the finished +pen. After tempering, the nib was ground and shaped to a point +suitable for fine or broad writing, as required. + +[Illustration: THE MODERN STEEL PEN] + +[Illustration: THE MODERN WRITING PEN] + +Once started, the steel pen made rapid strides in improvement. Mr. +James Perry, in 1824, started in England the manufacture of pens on a +large scale, and to him as well as Gillott is due the many improvements +which followed. + +Perry was the first to manufacture “slip” steel pens, up to this time +the pen and holder being one piece. + + “In times of yore, when each man cut his quill + With little Perryian skill; + What horrid, awkward, bungling tools of trade + Appeared the writing instruments, home made!” + +~THE MODERN WAY OF WRITING~ + +The steel pen of the present day has reached the pinnacle of +perfection, and the method of manufacture of this little but mighty +instrument of writing, though of extreme interest, is practically +unknown by the general public. To explain in detail the development +from the rough steel to the finished pen would needs make a book +in itself. And as it has been our intention to dwell, not upon the +manufacture of the pen, but to trace its history and development from +its most crude form, the Stylus, to the perfect and smooth-writing +steel pen of to-day, we will close our story with the well-worn epigram +of old, grim Cardinal Richelieu: + + “Beneath the rule of men entirely great, + The Pen is mightier than the Sword!” + + +How a Steel Pen is Made + + In the picture on the following page, we see the various processes + required in making a steel pen, together with a description of each + process: + +[Illustration: HOW A STEEL PEN IS MADE + + N^o. 1. ROLLED STEEL. + + N^o. 2. SCRAP. + + N^o. 3. BLANKS. + + N^o. 4. MARKING. + + N^o. 5. PIERCING. + + N^o. 6. ANNEALING. + + N^o. 7. RAISING. + + N^o. 8. HARDENING. + + N^o. 9. TEMPERING. + + N^o. 10. SCOURING. + + N^o. 11. GRINDING. + + N^o. 12. SLITTING. + + N^o. 13. No. 1. COLLEGE PEN No. 5. SCHOOL PEN. + (FINISHED PENS.) + COLORING AND VARNISHING. + + The pictures herewith printed are by the courtesy of the Spencerian + Pen Company + + _Raw Material._--The sheet steel is cut into strips of a convenient + length and width, and then rolled cold to the exact gauge necessary, + according to the pen to be manufactured. + + _Cutting the Blank._--This is a mechanical operation, and is effected + with the aid of a screw press, in which a pair of tools corresponding + with the shape of the pen has been fixed. On pulling a lever the + screw descends, driving the punch into the bed, which cuts a blank + with a scissors-like action, from the strip of steel. + + _Marking the Name._--This is done by means of a punch fixed in + the hammer of a stamp, worked by the foot. The blanks are rapidly + introduced between guides fixed on the bed of the stamp, and as + soon as the hammer has fallen the blank is thrown out and a new one + introduced. + + _Piercing._--The tools for this operation are of a delicate + character. The blanks are fed by hand, as above explained, and the + hole punched by a screw press. This is a most important process; the + pierce hole and slide slits determine the elasticity and regulate the + flow of the ink on the pen. + + _Annealing or Softening._--The blanks are still moderately hard and + before raising, it is necessary to soften them by heating to a dull + red, and allowing them to gradually cool. + + _Raising._--The operator places one of the soft blanks on a die to + which guides are affixed to keep it in position; then by moving the + handle of the press, the screw descends, forcing a die which rounds + the blank into the form of a pen. + + _Hardening._--The pen is now too soft, and is hardened by heating and + the immersing in oil while hot, after which it is thoroughly cleansed + from all grease. + + _Tempering._--The pens are now hard but very brittle, and in order + to correct this defect they are placed in an iron cylinder, and kept + revolving over a gas or charcoal fire until they acquire a proper + temper. + + _Scouring._--After soaking in diluted sulphuric acid, the pens are + placed in iron cylinders containing fine stone and water, or fine + sand, and revolved for several hours. When taken from these cylinders + they are bright and smooth. + + _Grinding._--This is a process performed by hand on a “bob,” or + wooden wheel covered with leather and dressed with emory, revolving + at high speed. A light touch on the emory wheel grinds off the + surface between the pierce hole and the point, to obtain proper + action and to assist the flow of ink. + + _Slitting._--This is a hand process performed with a press, the + cutters being as sharp as razors. The pen is placed in position by + means of guides, and must be cut with utmost precision from the + pierce hole to the point, the point must be divided exactly in the + middle, the least variation making the pen defective. + + _Coloring and Varnishing._--The pens having been polished to a bright + silver color are placed in an iron cylinder and kept revolving over + a gas or charcoal fire until the tint required is produced. They are + then immersed in a bath of shellac varnish, and afterwards dried in + an oven. + + _Examination._--Every steel pen passing through the factory is most + carefully examined before being boxed, and should the least fault be + found, it is at once rejected.] + + +Why Does a Pencil Write? + +You can use a pencil to write with or to make marks, because the pencil +wears off if you are scratching it on a surface that is rough enough +to make it do so. Writing, you know, is only a way of making marks in +such a manner as to make them mean something. You cannot write with a +pencil on a pane of glass, because the glass is so smooth that when +you move the pencil over its surface, the pencil will not wear off. To +prove to yourself that the tip of the pencil constantly wears off when +you write, you have only to recall that when you write with it a pencil +keeps getting shorter and shorter. A slate-pencil will wear down short +by merely writing with it, but a lead-pencil must be sharpened--that +is, you must keep cutting away the wood in order to get at the lead +inside. + + +Why Can’t I Write on Paper With a Slate-pencil? + +You cannot do so, because it takes something with a rougher surface +than paper to wear off the point of a slate-pencil. A slate is used to +write on with slate-pencils, because slate wears off the end of the +pencil easily, and also because you can rub out the writing on a slate +with water. Lead-pencils are used for writing on paper, but you must +have a rough surface on the paper to write on even with a lead-pencil. +Some kinds of papers have such a smooth surface that you cannot write +on them with a lead-pencil. + + +How Does a Pen Write? + +Writing with a pen, however, is quite different from writing with any +kind of pencil, because in writing with ink we do not wear off the end +of the pen, but have the ink flow from the pen. For this purpose we +must have a surface that will absorb the ink from the pen, and draw +the ink down off the pen and make it flow. A slate has no power of +absorption and therefore cannot draw the ink. A piece of blotting paper +is the best kind of paper for absorbing ink, but it is too much so for +writing purposes. For writing with ink we need a comparatively hard +surfaced paper that has absorbent qualities, but not too absorbent. + + + + +How Does a Blotter Take Up the Ink of a Blot? + + +It is because the blotter has a very excellent ability to absorb some +liquids. The thinner the liquid the more easily the blotter will absorb +it. Ink is thin--being mostly water--the blotter is of a loose texture +and has a rough surface. This gives the blotter the ability to pick up +the ink, just as a sponge would do. A sponge has what is called the +power of capillary attraction and so has the blotter. + + + + +Where Does Chalk Come From? + + +Deposits of chalk are found on some shores of the sea. A piece of chalk +such as the teacher uses to illustrate something on the blackboard +at school consists of the remains of thousands of tiny creatures +that at one time lived in the sea. All of their bodies excepting the +chalk--called carbonate of lime in scientific language--has disappeared +and the chalk that was left was piled up where it fell at the bottom +of the ocean, each particle pressing against the other with the water +pressing over it all until it became almost solid. It took thousands of +years to make these chalk deposits of the thickness in which they are +found. Later on, through changes in the earth’s surface, the mountain +of chalk was raised until it stood out of the water and thus became +accessible to man and school teachers. + + + + +How Did Men Learn to Talk? + + +Talking and the words used came into being through the desire of men +to communicate with each other. Before words became known and used +man talked to those about him by the use of signs, gestures and other +movements of the body. Even to-day when men meet who cannot talk the +same language they will be seen trying to come to an understanding by +the use of signs and gestures and generally with fair results. The +need of more signs and gestures to express a constantly increasing +number of objects and thoughts led to the introduction of sounds or +combination of sounds made with the vocal cords to accompany certain +signs and gestures. In this way man eventually developed a very +considerable faculty for expressing himself. Sign by sign, gesture +by gesture and sound by sound language was slowly developed. A man +would be trying to explain something to another by sign or gesture +and to make it more clear would make a sound or combination of sounds +to put more expression into his efforts. Finally the other man would +understand what was meant and he would tell some one else, using the +same signs, gestures and sounds. Later on it would develop that to +express thus any certain thought, act or the name of a thing, all of +the people in the community would make this same combination of sounds, +signs and gestures to express the same thing. Finally the gestures +and signs would be dropped and it was found that people understood +perfectly what was meant when only the sound or combination of sounds +was produced. That made a word. All the other words were made in the +same way, one at a time, until we had enough words to express all the +ordinary things and the combination of words became a language. The +children learned the language by hearing their parents talk it, and +that is how men learned to talk. + + + + +How Did Shaking the Head Come to Mean “No”? + + +The origin of this method of indicating “No” is found in the result of +the mother’s efforts in the animal kingdom of trying to feed her young. +A mother animal would be trying to get her young to accept the food she +brought them and tried to put it in their mouths. Perhaps, however, the +young animal had had sufficient food or did not fancy the kind of food +offered. The natural thing to do under the circumstances would be to +close the mouth tight and shake the head from side to side to prevent +the mother from forcing the food into the mouth. Thus we get the closed +lips and the shaking the head from side to side to mean “No.” In other +words, that kind of a way of saying “No” came from an effort to say “I +don’t want any.” + + + + +How Did a Nod Come to Mean “Yes”? + + +The idea of nodding to mean “Yes” comes from the opposite of the action +which, as just described, indicates a “No.” + +When the young animal was anxious to accept the offered food, it made +an effort to get at the food quickly. Hence, the pushing forward of the +head and the open mouth (always more or less opened when you nod to +indicate “Yes”) and an expression of gladness. You will notice if you +see anyone nod the head to indicate “Yes” that the lips are open rather +than closed, and that there is always a smile or an indication of a +smile to accompany it. In other words, the nod to mean “Yes” is only +another way of saying “I shall be pleased.” + + + + +Why Do We Count in Tens? + + +When man even in his uncivilized state found it necessary to count, the +only implements at hand were his fingers and toes, and as he had ten +toes and ten fingers, he naturally began counting in tens, and has been +doing so ever since. + +When we to-day count on our fingers we confine ourselves to our fingers +leaving our toes stay in our shoes, where they naturally belong. But +the first men who counted used both fingers and toes, and so he was +able to count twenty before he had to begin over again, while little +children to-day, when they count with their fingers, must begin where +they started after they reach ten. + + + + +What Does Man Mean by Counting Himself? + + +The expression “counting himself” was originated by the first man who +counted. Such a man would count all of his fingers and toes and the +result would be twenty. Then, so that he would remember the number of +times he had counted himself, he made a mark some place each time he +reached twenty. The mark he made was a mere scratch in the dirt or on a +hoe or something else. To make a scratch you merely, of course, score +the surface of whatever you happen to be scratching on, and that is how +it happened that the word “score” in our language to-day means as a +term in counting, twenty. + +There has been a great effort made to change our system of counting in +tens to one where you count in twelves. That would fit in very well +with our system of measuring which is based on the foot of twelve +inches, and of our calendar for recording the passage of time which has +twelve months. There are many arguments in favor of this change, among +the principal of which is the fact that it would make our problems of +division much easier, for our ten can be evenly divided by but two of +our single figures, two and five, whereas twelve can be evenly divided +by four of our single figures, viz., two, three, four and six. It is +believed that sooner or later the system of counting by twelve instead +of ten will be adopted by the entire world for counting everything. As +it is now we do part of our counting by one system and part of it by +another. + + + + +Where Did All the Names of People Originate? + + +There is no scientific plan by which people get their names. There is +not much except curious interest to be gleaned from the study of how +people got their names. + +In the earliest days of the world, or at least as soon as men had +learned to speak by sounds, all known persons, places and groups of +human beings must have had names by which they could be spoken of or +to, and by which they were recognized. The study of these names and +of their survival in civilization enables us in certain instances to +tell what tribes inhabited certain parts of the earth now peopled +by descendants of an entirely different race and of another speech +altogether. We learn such things from the names of mountains and other +things, for instance, which still cling to them. + +The story of personal names is very complex, but comes from very simple +beginnings. The oldest personal names were those which indicated a +group of people rather than individuals who may have been actually +related to each other or even bound together for reasons of protection +or other convenience. In the races of Asia, Africa, Australia and +America examination shows that groups of people who considered +themselves to be of the same relationship, attached to themselves the +name of some animal or other object, whether animate or inanimate, from +which they claimed to be descended. This animal or object was called +the “totem,” and thus the earliest and most widely spread class and +family names are totemistic. Such groups called themselves by names +from wolves, turtles, bears, suns, moons, birds, and other objects, and +these people wore badges with pictures of the animal or object from +which they took their names to identify them to other people. + +When, then, we come to investigate the giving of personal names among +the tribes, we see that most uncivilized races gave a name to each +new-born infant derived from some object or incident. So a new-born +member of the “Sun” tribe would be named “Dawn,” and would be known +as “Dawn” of the “Sun” tribe; or perhaps a new-born son of the tribe +of “Wolf” would be called “Hungry,” and be known as “Hungry Wolf.” A +member of the “Cloud” tribe would be named “Morning,” because he was +born in the morning. He would always be known as “Morning Cloud.” + +Later, as society became more established and paternity became +recognized, we find the totem name give way to a gentile name. +Among the Greeks and Romans the system was early adopted and proved +satisfactory. Thus we have Caius Julius Caesar. Caius indicates that +he is Roman; Julius is the gentile name given him and the Caesar a sort +of hereditary nickname. On the other hand, the early Greeks began the +system of introducing a local name instead of the gentile name. Thus +Thucydides (obtained from the grandfather), the son of Olorus, of the +Deme (township) of Halimusia. + +~HOW DIFFERENT NAMES ORIGINATED~ + +This was all right and suited the purposes of the Greeks and Romans, +who had plenty of time to give full explanations in this way. But +in Europe, for instance, civilization demanded more speed, and the +increase of population demanded more names, so that nicknames and names +indicating personal descriptions and peculiarities came into use. Such +names as Long, Short, Small, Brown, White, Green and others of the +same kind came from this source, and as families grew these surnames +stuck to the family and parents gave their children Christian names +to further distinguish them as individuals. Other surnames such as +Fowler, Sadler, Smith, Farmer, etc., became attached to people because +of the occupations in which they were engaged, and yet other names +were derived from places. The owner of an extensive estate would be +designated by a Christian name which might be George (after his King) +and then to indicate his landownership, von (meaning of) Wood, making +the combination of George von Wood, meaning George, the owner of the +place called Wood. On the other hand, he might have working for him a +laborer who lived at the place and, if his name was Hiram, they would, +to indicate where he belonged, put the Wood after the Hiram; but, lest +there be confusion as to his class, they would put an At before the +Wood and make him Hiram Atwood, indicating his Christian name, where he +worked and the fact that he was not a landowner. + +Many other names were invented in similar manner. When Adams became so +common that there would likely be confusion on account of there being +so many of them, a son of one of the Adams family would add to the name +the fact that he was a son by writing his name Adamson, and thus start +a new family name. Thus, in the same way also came Willson, Clarkson, +and other names of that kind. + +For a long time the Jews had only one word for a name, such as Isaac, +Jacob, Moses, etc. They became so numerous that it was impossible to +distinguish them, and so a commission was named to give surnames to +all the Jews in addition to their other names. As the race was then, +as now, held in derision by the rulers of many nations into which the +tribe had become scattered, the people who had charge of the naming of +the Jews took advantage of the opportunity to make sport of them, and +gave them such names as + +Rosenstock (Rose bush), + +Rosenszweig (Rose twig), + +Rosenbaum (Rose tree), + +Blumenstock (Flower bush), + +Blumenthal (Flower valley), + +etc., etc. + +Our Christian names are from similar sources, and while many of them +are well selected because of their beautiful meanings, there are many +of them which mean nothing as words as they were only invented for the +purpose of giving a new name to a new child. + + + + +Why Can You Blow Out a Candle? + + +When you light a candle it burns, because the lighted wick heats the +wax sufficiently to turn it into gases, which mix with the oxygen in +the air and produce fire in the form of light. You know it is not easy +to light a candle quickly. You must hold the lighted match to the wick +until the wax begins to melt and change to gases. As long as the wax +continues hot enough to melt and turn to gas the candle will burn until +all burned up; but if there is a break in the continuous process of +changing the wax to gas, the light will go out. Now, when you blow at +the lighted candle, you blow the gases which feed the flame away from +the lighted wick, and this makes a break in the continuous flow of gas +from the wax to taper, and the light goes out. + +[Illustration] + + + + +The Story in a Photograph + + +How Does a Camera Take a Picture? + +When we look upon the surface of a mirror we see the image of ourself +and our surroundings. The extent of the view depends upon the size of +the mirror and the distance we are standing from it. + +If we hold the mirror close to our face we see only the face, or +perhaps but a portion of it, and the farther away we are the more +the mirror will reflect, only, of course, the various images will be +smaller. The mirror reflecting exactly what the eye sees, without doubt +had a great influence in inducing the experiments that resulted in the +process we call photography. + +The taking of a photograph with a camera may in a way be compared +with the action of your eyes, when you gaze upon your reflection in a +mirror, or look at any object or view. Any object in a light strong +enough to render it visible will reflect rays of light from every point. + +Now, the eye contains a lens very similar in form to that used in a +camera. This lens collects the rays of light reflected from the object +looked at and brings them to a focus in the back of the eye, forming an +image or picture of whatever we see, just as the mirror collects the +rays of light and reflects them back through the lens of the eye. + +Certain nerves transmit the impression of the image so focused in the +back of the eye to the brain and we experience the sensation of sight. + + +What Is the Eye of the Camera? + +The lens is the eye of the camera, and the process we call photography +is the method employed to make permanent the image the eye or lens of +the camera presents to a sensitive surface within the camera. + +Fig. 1 shows a simple form of camera, it being merely a light tight box +with a lens fitted to the front, and a means for holding a sensitive +plate at the back, the plate being placed at just the right distance to +focus the rays of light admitted through the lens in exactly the same +manner as the rays of light pass through the lens of the eye and come +to a focus in the back part of the eye. + +Now, if we could look inside the camera we would note that the image +was inverted, or upside down. + +Fig. 2 will explain this. + +The rays of light from “A” pass in a straight line through the lens +“B” until they are interrupted by “C,” upon which they strike, forming +an upside down image of the object “A.” But, you exclaim, “we do not +see things upside down.” No, we do not, because some mental process +readjusts this during the passing of the impression from the eye to our +brain. + +Let us suppose we have our camera loaded with its sensitive plate or +film. We select some object or view we wish to photograph, uncover +the lens for an instant, and let the light impress the image upon the +sensitive surface of the plate or film. Now, how are we going to make +this image permanent? + +If we were to examine the creamy yellow strip of film upon which the +picture was taken there would seemingly be no difference between its +present appearance and before the snapshot was made. + +Now let us suppose that this strip of film is a little trundle bed, and +in it tucked securely away from the light are many hundreds of little +chaps called silver bromides, little roly-poly fellows lying just as +close together as possible, and protected by a coverlet of pure white +gelatine. + +~HOW A PHOTOGRAPH IS DEVELOPED~ + +Until the sudden flash of light in their faces when the picture was +taken, they have been content to lie still and sleep soundly. Now +they are seized with a strange unrest, and each little atom is eager +to do his part in showing your picture to the world. Alone they are +powerless, but they have, all unbeknown to them, some powerful chemical +friends, who, organized and aided by the photographer, will bring +about their transformation. These chemicals, with the help of the +photographer, form themselves into a society called the developer. + +The photographer takes just so many of the tiny feathery crystals of +pyro, just so many of the clear little atoms of sulphite of soda, and +just so many little crystals of carbonate of soda, and tumbles them +all into a beaker of clear cold water. Unaided by each other, any one +of these chemicals would be powerless to help their little bromide +of silver friends. The first of these chemicals to go to work is the +carbonate of soda. + +He tiptoes softly over to the trundle bed and gently begins turning +back the gelatine covers over the little bromide of silver chaps, so +that Pyro can find them in the dark. + +It is Pyro’s mission to transform the little silver bromides into +silver metal, but he is rather an impulsive chap, so he is accompanied +by sulphite of soda, who warns him not to be too rough, and whose sole +mission is to strain his eagerness to help his friends. + +“Go slow now,” says Sulphite, “don’t frighten the little silver +bromides, or else you’ll make them cuddle up in heaps, and the picture +won’t be as nice as if you wake them up gently and each little bromide +stayed just where he belonged.” + +After all the little silver bromides that the light shone on have been +transformed into metallic silver by the developer, another chemical +friend has to step in and carry away all the little bromides that were +not awakened by the flash of light. + +This friend’s name is “Hypo,” and in a few minutes he has carried away +all the little bromides that are still sleeping, so that the trundle +bed with the now awakened and transformed silver bromides will, after +washing and drying, be called a negative, and ready to print your +pictures from. + +If we take this negative, as it is called, and hold it up to the +light, we will see that everything is reversed, not only from right to +left, but also that whatever is white or light in color is dark in the +negative, and that what would correspond to the darker parts of our +picture are the lightest in the negative, and it is from these facts +that we give it the name negative. + +Now, to get our picture as it should be, we must place this negative in +contact with a sheet of coated paper that is also sensitive to light. + +So we place the negative and the sheet of sensitive paper in what is +called a printing frame, with the negative uppermost, so that the light +may shine through the negative, and impress the image upon the sheet of +sensitive paper. Now, it stands to reason that if the lightest parts of +our picture are the darkest in the negative that less light can pass +through such portions of the negative in a given time, so that with the +proper exposure to light the image upon the sheet of sensitive paper +will be a correct picture of whatever the lens saw. + +[Illustration: The swiftest thing that the human race has ever put into +motion is the steel projectile of a twelve-inch gun. No human eye can +follow its flight. Released at a pressure of forty thousand pounds to +the square inch--in a heat at which diamonds melt and carbon boils--it +hurls through the air at the rate of twenty-five miles a minute, and +reaches the mark _ahead of its own sound_! (Pictures and story by +courtesy of McClure’s Magazine.)] + + +TWENTY-FIVE MILES A MINUTE + +AN EXCLUSIVE STORY, ILLUSTRATED WITH A SERIES OF REMARKABLE PHOTOGRAPHS +TAKEN WITH THE FASTEST CAMERA IN THE WORLD + +BY CLEVELAND MOFFETT + +~HOW SHOOTING SHELLS ARE PHOTOGRAPHED~ + +One of the most progressive branches of our military service is the +Department of Coast Defenses, which, under the far-seeing guidance of +General E. M. Weaver, holds our shores and harbors in a state of alert +preparedness against foreign aggression. At Hampton Roads sits the +Coast Artillery Board, composed of officers and consulting engineers +to whom are referred all problems relating to coast artillery, and who +have the responsibility of testing all new instruments proposed for +artillery use. The purpose of this article is to describe one among +several notable achievements of the Hampton Roads Coast Artillery +School, this particular work having been done by Captain F. J. Behr of +the Coast Artillery Corps, who, after years of effort, has recently +developed a system that makes it possible to take pictures of the +swiftest moving bodies, the great steel projectiles of our biggest +guns--to seize them with the camera’s eye as they hurl through the air +at enormous velocities or at the very moment of their emergence from +the gun muzzles, and to preserve these images, never seen before, for +military study and comparison. Captain Behr was ably assisted in this +work by Engineer J. A. Wilson. + +[Illustration: THE FASTEST CAMERA IN THE WORLD + + The big gun, equipped with the fastest camera shutter in the world, + about to be fired and the shell photographed. + +For years a young officer of the Coast Artillery has been trying to +devise a camera so incredibly swift that it will record every stage of +this lightning flight from the gun-barrel to the target. At last he has +succeeded. His photographs--some of them taken one hundred thousandth +of a second apart--have revealed remarkable and unsuspected facts to +the military world. The story of his invention had never before been +told.] + + +Reckoning in Millionths of a Second. + +Some of the increments and decrements of time involved in the series of +photographs herewith published (several of them for the first time) are +as small as one ten-thousandth part of a second. And Captain Behr has +devised a method of taking photographs of projectiles as they arrive at +a steel target and penetrate the target, inch by inch, that involves +increments or decrements of time as small as the one hundred-thousandth +part of a second. To the uninitiated it seems incredible that such +infinitesimal divisions of time can be used in practical calculations; +but every trained physicist knows that in wireless work scientists of +to-day speak casually of experiments that take account of _two-tenths +or one-tenth of a millionth part of a second_! + +[Illustration: THE PROJECTILE EMERGING FROM MORTAR + +In this photograph--the first of a remarkable series showing five +stages of a moving projectile--the half-ton projectile seems to be +standing still, but really it is traveling at the rate of 900 miles an +hour. The gunners here work in concrete pits 34 feet high. Underneath +the mounts are the powder magazines. Each pit has four mortars usually +served by an entire Coast Artillery Company. The projectiles are the +same as those used in the twelve-inch guns, but less powder is required +because mortar projectiles are hurled high in the air, not straight at +a vessel, and deliver their destructive blows downward from a great +height.] + +[Illustration: THE SMOKE RINGS WHICH APPEAR + +This second photograph shows the projectile almost entirely out of the +mortar. Its sharp nose may be seen above the “gas-ring” forming at its +upper end. These “gas-rings,” or “smoke-rings,” come without warning, +and only occasionally, perhaps once in eight or ten shots. They rise +swiftly to the height of fifty or a hundred feet, growing larger +and larger, and giving forth a weird, shrieking sound like a second +projectile. Some insist that these “smoke-rings” are as hard as steel, +owing to the enormous compression of their composing gases, and the +story is told of a bird caught in the path of one of them and torn to +pieces.] + +What happened to the projectile after it leaves the gun, or after +the discharge of the gun, and before the projectile has had time to +issue from the gun-barrel? What is the action at the muzzle of gases +generated? What shape do these gases assume as they leave the gun? What +causes the much-discussed “gas-rings” that sometimes form when a mortar +is fired, and oftener do not form? What phenomena attend the arrival +of the projectile at a solid steel target? Is the steel actually fused +by the heat of impact? Is it vaporized? Or what? These are some of +the questions that Captain Behr set himself to solve, or to help in +solving, as he worked out his methods of rapid photography. His aims +were strictly military, but his results make fascinating appeal to the +general imagination. Fancy doing anything in the one hundred-thousandth +part of a second! + +[Illustration: THE PROJECTILE HIDDEN BY THE SMOKE CONE + +In the third photograph the smoke-cone is almost perfect and gives the +famous “powder-puff” effect. It still hides the projectile, although +the latter is traveling at a velocity that would take it from New York +to Chicago in one hour. At night the “gas-rings” present a startling +and fascinating appearance, burning with a reddish orange glow, and +whirling with a complicated double motion, strange opalescent balls, +like rings of Saturn. A study of these photographs--the first record +ever made of the “gas-rings”--has led some experts to the conclusion +that the cause of the rings is defective ramming of the projectile.] + +[Illustration: THE PROJECTILE EMERGING FROM SMOKE CONE + +The fourth photograph shows the projectile emerging from the smoke-cone +about thirty feet above the muzzle of the mortar. The men who fire +these mortars from the mortar-pits never see the distant target or +vessel they are firing at, but point their mortars according to +directions transmitted to them (usually by telephone) from observers at +distant stations. And so great a degree of precision has been attained +that, on certain practice occasions at Hampton Roads, a record of nine +hits out of ten shots has been scored on a moving target five miles out +in the ocean. This picture shows the smoke-cone as first seen by the +human eye.] + +Captain Behr’s general idea was to utilize some phenomena connected +with the discharge to actuate, by electrical connections, a mechanism +that would work a rapid shutter in a properly placed camera. The +phenomenon of concussion was tried first--the smash of air against a +little swinging door; but this was much too slow. The projectile was +hundreds of yards away before the camera had registered its picture. +And that chance was gone! + +[Illustration: THE PROJECTILE HIGH IN THE AIR + +In the fifth photograph the projectile is seen entirely clear of the +smoke-cone and well started on its long flight. Climbing into the sky +at this steep angle, it will reach a height of from three to six miles +before it begins to descend. There are harbors on our coasts guarded by +so many guns and mortars that if these were fired simultaneously they +could hurl against a given small area a converging rain of projectiles +aggregating more than fifty tons in their combined mass. A minute later +they could hurl another fifty tons against the same small area; and so +on as long as the ammunition lasted.] + +In the next trial, several months later, Captain Behr arranged to +have the electrical connections made or broken by the movement of the +gun-carriage itself in recoiling; but the result was unsatisfactory. +Nor was he more fortunate at the succeeding target practice, when, +having placed the apparatus farther forward on the parapet, he had the +camera demolished by the force of the concussion and several blades of +the rapid shutter broken. He was satisfied, now, that his effort to +actuate the camera mechanism from the gun-carriage would never give the +requisite precision in results, and he saw that he must work with a +device functioning more reliably. + +In the months that followed before the next target practice, the +Captain did some experimenting, and finally determined making the +projectile itself displace a length of piano-wire fixed across the +muzzle of the gun, and thus actuate the electrical system and operate +the shutter. In this way he eliminated troublesome variables of +recoil, elasticity of the carriage, etc., leaving to determine only +the time element of the electrical system to function. This result was +admirable, and, after taking several similar pictures, the captain +found that he could now operate with great precision--that is, he could +get the same phase of the discharge with almost identical shapes of +gas-cone and smoke-cloud, and he could get these every time. + +In the fall of 1912 Captain Behr succeeded in obtaining a series of +extremely rapid photographs showing a twelve-inch mortar battery in +action. In taking these pictures the camera was placed on an elevation +about ten feet above the concrete floor and about sixty feet back of +the mortars. The electrical device for working the shutter was actuated +by the mortar itself in its recoil. These pictures were taken in about +one five-thousandth of a second--which is the more remarkable as the +last two were taken in the shade after 4.30 A.M. The first three were +taken about noon, in the sunshine, as the shadows show. + +So great was the precision of the electrical device as to render +possible the photographic recording of these mortar projectiles, +moving at great velocities, in almost any desired position after the +discharge, say two feet away from the muzzle, or six feet away, or +twenty feet away, or right at the muzzle, as shown in the first mortar +picture, where the great projectile has been caught in its flight half +way out of the mortar. + + +Pictures Never Seen By the Human Eye. + +~A CAMERA THAT IS FASTER THAN THE EYE~ + +It is interesting to note that of these five mortar pictures, +representing five phases of the firing, only the last two are ever +seen by the human eye. The far swifter camera, acting in about one +five-thousandth of a second, has caught all these phases as reproduced +here; but, to the ordinary observer standing by, the first visible +impression after firing is that of the smoke-cone as developed in +Number Four. The strange “powder-puff” effect shown in Number Three is +never seen; nor the earlier effects in Numbers One and Two. Nor is any +sound heard by an observer or by the gun crew until the third or fourth +phase has been reached. This is a matter of simple calculation. + +Sound travels through the air very slowly as compared with light, and +in Numbers One, Two, and Three, although the crashing explosion has +taken place and the projectile is already started on its long journey, +the men (even the lanyard man, who is nearest), have heard nothing, +since the sound-waves have not yet had time to reach their ears. Nor +has the mortar itself had time to recoil, as it does presently, down +into the well in the floor of the pit. + +The men aboard the towing vessels that drag the floating targets during +gun and mortar practice would seem to be in a dangerous position, since +the tow-line is not more than two hundred yards long for guns and +five hundred yards long for mortars, and a very slight error in aim +or adjustment might cause a deviation of several hundred yards when +the range is eight or ten thousand yards. As a matter of fact, such +errors do not occur, and a gun-pointer who would make a right or left +deviation from the target of ten yards, or at the most fifteen yards +at a distance of five miles, would be considered unfit for his job. +In one or two rare instances a towing vessel has been struck when a +projectile has fallen short and then ricochetted to the right, as it +invariably does owing to its rotation in that direction. The rifling of +the gun-barrel causes this rotation. + +[Illustration: This shows one of Captain Behr’s earliest efforts to +photograph the projectile from a twelve-inch gun. The man on the +platform has been adjusting the electrical connections that actuate +the camera mechanism. The halo effect at the muzzle of the gun is due +to compressed air caused by the forward rush of the projectile. The +projectile has not yet emerged from the muzzle of the gun. On the right +is the place where the “Merrimac” and the “Monitor” had their famous +fight.] + +Sometimes these great projectiles ricochet several times, and go +bounding over the water as a pebble skips along the surface of a +mill-pond, only there may be the distance of a mile or more between +these giant leaps. + + +The Projectile Travels Faster Than the Sound It Makes. + +A strange phenomenon is witnessed by the observer on a towing vessel as +he looks, rather uneasily perhaps, toward the distant shore battery, +that seems to be firing straight at him. First there is a flash and +a puff of smoke; then nothing for a period of seconds, while the +projectile is on its way; then suddenly a great splash as the mass of +iron strikes the water. Up to this moment there has been no sound of +the discharge, no sound of the projectile, since it travels faster than +the sound-waves; but now, _after_ it has buried itself in the ocean, is +heard its own unmistakable voice, a low, buzzing _um-m-m-m_ approaching +from the shore. The projectile itself has arrived _before_ the sound +that it makes in transit, and the sound arrives afterward. Last of all +is heard the boom of the discharge. + +[Illustration: A GUN THAT PHOTOGRAPHED ITS OWN SHOT + +In this beautiful picture the hurling projectile was itself the +photographer: that is, in passing out of the gun-barrel, it broke a +length of piano-wire stretched across the muzzle and thus automatically +closed an electrical circuit that actuated the camera mechanism. And so +rapid was the shutter that the great shot hurled forth in the discharge +photographed here has not yet had time to issue from the smoke-cone, +where it is still hidden.] + +Owing to the great velocity of gun projectiles, it is almost impossible +for an observer near the target to see them as they approach; but a +trained eye can discern the slower moving mortar projectiles as they +drop out of the sky, shrieking as they come, curving downward from a +height of four or five miles, half a ton falling from a height of four +or five miles. + +[Illustration: EXPLODING A SUBMARINE MINE + +This photograph illustrates another important form of coast +defense--the submarine mine. A target about 5 by 5 feet, with a red +flag at its apex, is towed across the mine-field, the mines being +exploded electrically from a shore station several miles away. The +methods of laying and exploding these mines are carefully kept secrets. +In this case a charge of five hundred pounds of the newest explosive +was used. Fragments of the shattered target and mine-buoy are seen at +the right of the picture. Tons of water are hurled into the air by +these explosions, and hundreds of fish are killed or stunned.] + +It is difficult to realize what an enormous force is released when one +of these twelve-inch guns is discharged. The pressure inside of the +gun behind the projectile is between thirty-five and forty thousand +pounds to the square inch. No engine or machine made by man produces +anything like this pressure. The boiler pressure in steam-engines, +or in big turbines driven by superheated steam, does not exceed two +hundred or three hundred pounds to the square inch. The huge hydraulic +presses that would crumple up a steel girder do not exert a pressure +of more than one thousand pounds to the square inch. The only reason +a gun-barrel can resist this pressure (forty thousand pounds to the +square inch) is that it is built up in a series of concentric steel +hoops or tubes shrunk one over the other until there is a resistance +capacity of from seventy thousand to ninety thousand pounds to the +square inch. Even at rest, the barrels of these great guns are under +such enormous compression, from being thus squeezed within these outer +steel coverings, that, if the retaining steel jackets were suddenly +cut, the tubes would blow themselves into pieces from the violent +reaction of release. + +Not only does this smokeless powder, burning inside these guns, +produce enormous pressure, but it generates inconceivably great heat. +Water boils at 100° Centigrade; iron melts at 1400°; platinum and +the most resistant metals at 2900°; while the hottest thing on earth +is the temperature of the electric arc, in which carbon boils. This +temperature is between 3000° and 4000° Centigrade, and is believed to +be the same as that of these great powder chambers when the gun is +fired. Thus a diamond, the hardest substance known, would melt in the +barrel of a twelve-inch gun at the moment of discharge. The consequence +is that at each discharge of a big gun a thin skin of metal inside +the barrel is literally fused, and this leads to rapid erosion of +the softened surfaces under the tearing pressure of gases generated. +The rifling is worn away; the band over the projectile becomes +loose-fitting; and soon the huge gun, that has cost such a great sum, +is rendered unfit for service. The life of a twelve-inch gun is only +450 rounds, that is, the gun would be worn out if fired every three +minutes for a single day. After that a new life may be given it by +boring out the inner tube and putting in a new steel lining. + + +A Secret for Which Foreign Governments Would Pay Millions. + +A few words may be added about the formidable smokeless powder used in +these great guns. This powder, in spite of its terrible power, is of +innocent appearance, and a small stick of it may be held safely in the +hand while it burns with a vivid yellowish flame. There is no danger +of its exploding or detonating like gun-cotton, and yet it is made +from gun-cotton, treated by a colloiding process that is one of our +jealously guarded military secrets. There are foreign governments that +would give millions to know exactly how this powder is made and how it +is preserved for years without deterioration. The recent destruction of +two ships of the French navy was due, it is believed, to deterioration +of their smokeless powder. + +[Illustration] + + + + +Why Do Some Eyes In a Picture Seem to Follow Us? + + +If a person’s picture is taken with the eyes of the person looking +directly into the lens or opening of the camera, then the eyes in +the picture will always be directly on and appear to follow whoever +is looking at it. This is also true of paintings. If a subject being +painted is posed so as to look directly at the painter, and the artist +paints the picture with the eyes so pointed, then the eyes of the +picture will follow you. When you are looking at a picture of a person +and the eyes do not follow you, you will know at once that he was not +looking at the camera or artist when the picture was being taken or +painted. + +[Illustration] + + + + +Where Does a Light Go When It Goes Out? + + +~WHY YOU CAN BLOW OUT A CANDLE~ + +To understand the answer to this question fully you will first have to +learn what light is, and particularly that it is not the flame from +the gas jet or of the lamp or candle that is actually the light, but +that light consists of rays or waves in the ether, which is constantly +in all space and even in our bodies, coming from the something that +is burning. This in the instance above mentioned would be the gas +burning as it comes out of the gas jet, the oil in the lamp as it comes +up through the wick or the flame of the candle. We are apt to call +a lighted gas jet a lamp, or a candle, light, because it is steady. +Really, however, there is no such thing as keeping light in a room in +an actual sense, for rays of light travel from the substance which +produces them faster than anything else we know of in the world. The +first thing a light wave does when it is once created is to go some +place, and it does this at the rate of 186,000 miles per second. If it +cannot penetrate the walls of the room it is either reflected back in +the direction from which it came or transformed by the objects which it +strikes into some other kind of energy. + +When you look at the rays coming from a gas jet, you do not see one ray +for more than, say the millionth part of a second, but because these +rays of light come so fast one after the other from the burning jet and +spread in all directions, they seem to be continuous. + +So you see that the rays of light are going away as fast as they are +coming from the gas jet. They either go on as light or, as said above, +are changed into other forms of energy when they strike things they +cannot penetrate in the form of light, or rather one thing, which is +heat. A large part of it goes into the air in the room in the form of +heat, as you well know, now that it is called to your attention. Some +of it goes into the furniture and some of it is changed into another +form of heat, which, combining with the chemicals in other things it +mixes with, changes their appearance and usefulness. As, for instance, +the carpets and hangings in the room, the colors of which become faded +when exposed to light rays too much. The heat from the light rays is +responsible for the fading of colors in our garments as well. + +When you “put out the light,” as we say, or turn off the gas, you cut +off the source of light. Really, then, our expression that “the light +goes out” is only true while the gas is lighted, for from the flaming +gas jet the light is going out all the time, whereas when the gas is +turned off no light is being produced, and when you turn off the gas +you do not turn out the light, but only that which makes light. + + + + +Why Does a Fire Go Out? + + +Fire will go out naturally when there is nothing left to burn, or it +will go out if it cannot secure enough oxygen out of the air to keep it +going. In the first case it dies what we might call a “natural death,” +and in the latter case the fire practically suffocates. The fire in +the open fireplace, if it has plenty of air, will burn up everything +burnable that it can reach. The stones of the fireplace or other parts +of a stove will not burn, because they have already been burned, and +you cannot burn anything a second time, if all of the oxygen in it was +burned out of it the first time. + +Now, then, to burn up a thing, you must first start a fire under it, +and then keep a constant draft of air playing on it from beneath, or +the fire will die out. The more difficult a thing is to burn, the more +important it is that you have plenty of draft. If the ashes accumulate +under the fire the air cannot go through them in sufficient quantity +and the fire will go out. Other things which prevent the current of air +from going up through the fire will cause it to go out. That is why we +close the lower door of the furnace, to keep the fire from burning out. +When we shut off the draft of air from below, the fire in the furnace +burns slowly, i. e., it just hangs on, so to speak. + + + + +Why Does a Lamp Give a Better Light With the Chimney On? + + +When a lamp is burning without a chimney it generally smokes. That +is because the oil which is coming up through the wick is being only +partially burned. The carbon, which is about one-half of what the oil +contains, is not being burned at all, and goes off into the air in +little black specks with the gases which are thrown off. The reason +the carbon is not burned when the chimney is off is that there is not +sufficient oxygen from the air combining with it, as it is separated +from the oil in the partial combustion that is going on. To make the +carbon in the oil burn you must mix it with plenty of oxygen at a +certain temperature, and this can only be done by forcing sufficient +oxygen through the flame to bring the heat of the flame to the point +where the carbon will combine with it and burn. When you put the +chimney on the lamp you create a draft which forces more oxygen through +the flame, brings the heat up to the proper temperature and enables the +carbon to combine with it and burn. When you take the chimney off again +the heat goes down, when the draft is shut off and the lamp smokes +again. + +The chimney also protects the flame of the lamp from drafts from the +sides and above, and helps to make a brighter light, because a steady +light is brighter than a flickering one. + +The draft created by the chimney also forces the gases produced by the +burning oil up and away from the flame. Some of these gases have a +tendency to put out a light or a fire. + + + + +Does Light Weigh Anything? + + +To get at the answer to this question we must go back to the definition +of light. Light is a wave in the ether and contains no particles of +matter. It, therefore, does not weigh anything at all. + +When men had studied light thoroughly, however, they came to the +conclusion that it must have the power of pressure, which, from the +standpoint of results, would amount to the same thing as having weight. +They reasoned that if you had a perfect balance and let sunlight shine +down on one of the sides of the balance, that side should go down under +the pressure of light. In their first experiments along this line men +failed to show that under such conditions the side of the balance on +which the light shone did go down, but by continuous experiments it was +proved finally that the light did exert a sufficient pressure to cause +the scales to go down, and in effect this is the same as having weight; +but this has been found to be a common property of rays of various +kinds, including heat, and we, therefore, do not speak of this quality +as weight, but as the power of radiating pressure. + + + + +Why Does a Stick Seem to Bend When Put in Water? + + +When light passes from one medium to another, as for example from glass +or water to air, or from air or glass to water, the rays of light +change their course, thus making them seem to be bent or broken. The +rays of light from the part of the stick in the water take a different +direction from the rays from the part which is out of the water, giving +the appearance of breaking or bending at the place where the air and +water meet. It is, of course, the light rays which are bent and not the +object itself. + +This bending or changing of the path of light rays is called +refraction. If you place a coin in a glass of water so that it may be +viewed obliquely, you can apparently see two coins, a small one through +the surface of the water and another apparently magnified through the +side of the glass. + +This is due only to the absolute principle that rays of light change +their direction in passing from one thing to another, and on this +principle of the rays of light our optical instruments, including the +microscope, the telescope, the camera and eyeglasses are based. + + + + +What Makes the Stars Twinkle? + + +I might tell you, just to show how clever I am, that stars do not +twinkle at all, and leave you with that for an answer. But since they +really do seem to twinkle, and that is what causes your question, +I will tell you. As we have already learned in our talks about the +stars and the sky in general, the stars are suns which are constantly +throwing off light, just as our sun gives us light, and when this light +strikes the air which surrounds the earth it meets many objects--little +particles of dust and other things always floating about in it. The +light comes to us in the form of rays from the stars and some of +these rays strike particles of various kinds in the air and are thus +interfered with. If you are looking at a lighted window some distance +away and there are a lot of boys and girls or men and women running +past the window, one after the other, rapidly, it will make the +light in the window appear to twinkle. The twinkling is due to the +interference which the rays of light encounter while traveling toward +the eye. + + + + +Why Does an Onion Make the Tears Come? + + +That is nature’s way of protecting the eyes from the smarting which the +onion would cause in your eyes if the tears did not come quickly and +overcome the bad effect so produced. Tears are provided for washing the +ball of your eyes. Every time you wink a little tear is released from +under the eyelid, and the wink spreads it all over the eyeball. This +washes down the front of the eyeball and cleanses it of all dust and +other things that fly at the eye from the air. Then the tear runs along +a little channel, much like a trough, at the lower part of the eye, +and out through a little hole in the eye, and in this case the tear is +really only an eye-wash. Many things, but more often sadness or injured +feelings, start the tears coming so fast from under the eyelid that the +little trough at the bottom and the hole in the corner of the eye are +too small to hold them or carry them off, so they roll over the edge of +the lower eyelid and down the face. These are what we call tears. Among +other things that will cause tear-glands to cause an over-supply of +eye-wash to come down, are onions. What they give off is very trying to +the eyes, and so, just as soon as the something which an onion throws +off hits the eyeball, the nerves of the eye telegraph the brain to turn +on the tears quickly, and they come in a little deluge and counteract +the bad effect of the onion. + +[Illustration: SOME REMARKABLE PICTURES WITH A FAST CAMERA] + +[Illustration] + +[Illustration] + +[Illustration] + +[Illustration] + +[Illustration: THE CAVE MAN OF PREHISTORIC TIMES WHO UNCONSCIOUSLY +INVENTED AMMUNITION] + + + + +The First Missile + + +~HOW MAN LEARNED TO SHOOT~ + +A naked savage found himself in the greatest danger. A wild beast, +hungry and fierce was about to attack him. Escape was impossible. +Retreat was cut off. He must fight for his life--but how? + +Should he bite, scratch or kick? Should he strike with his fist? These +were the natural defences of his body, but what were they against the +teeth, the claws and the tremendous muscles of his enemy? Should he +wrench a dead branch from a tree and use it for a club? That would +bring him within striking distance to be torn to pieces before he could +deal a second blow. + +There was but a moment in which to act. Swiftly he seized a jagged +fragment of rock from the ground and hurled it with all his force at +the blazing eyes before him; then another, and another, until the +beast, dazed and bleeding from the unexpected blows, fell back and gave +him a chance to escape. He knew that he had saved his life, but there +was something else which his dull brain failed to realize. + +He had invented arms and ammunition! + +In other words, he had needed to strike a harder blow than the blow of +his fist, at a greater distance than the length of his arm, and his +brain showed him how to do it. After all, what is a modern rifle but a +device which man has made with his brain permitting him to strike an +enormously hard blow at a wonderful distance? Firearms are really but a +more perfect form of stone-throwing, and this early Cave Man took the +first step that has led down the ages. + +This strange story of a development has been taking place slowly +through thousands and thousands of years, so that today you are able to +take a swift shot at distant game instead of merely throwing stones. + +[Illustration: THE SLING MAN IN ACTION + +PRACTICE DEVELOPED SOME WONDERFUL MARKSMEN AMONG THE USERS OF THIS +PRIMITIVE WEAPON] + +We do not know the name of the man who invented the sling. Possibly +he did not even have a name, but in some way he hit upon a scheme +for throwing stones farther, harder, and straighter than any of his +ancestors. + +The men and women in the Cave Colony suddenly found that one +bright-eyed young fellow, with a little straighter forehead than the +others, was beating them all at hunting. During weeks he had been going +away mysteriously, for hours each day. Now, whenever he left the camp +he was sure to bring home game, while the other men would straggle back +for the most part empty-handed. + +Was it witchcraft? They decided to investigate. + +Accordingly, one morning several of them followed at a careful distance +as he sought the shore of a stream where water-fowl might be found. +Parting the leaves, they saw him pick up a pebble from the bank and +then to their surprise, take off his girdle of skin and place the stone +in its center, holding both ends with his right hand. + +Stranger still, he whirled the girdle twice around his head, then +released one end so that the leather strip flew out and the stone shot +straight at a bird in the water. + +The mystery was solved. They had seen the first slingman in action. + +The new plan worked with great success, and a little practice made +expert marksmen. We know that most of the early races used it for +hunting and in war. We find it shown in pictures made many thousands of +years ago in ancient Egypt and Assyria. We find it in the Roman Army +where the slingman was called a “funditor.” + +Surely, too, you remember the story of David and Goliath when the young +shepherd “prevailed over the Philistine with a sling and with a stone.” + +Yet slings had their drawbacks. A stone slung might kill a bird or even +a man, but it was not very effective against big game. + +What was wanted was a missile to pierce a thick hide. + +Man had begun to make spears for use in a pinch, but would you like +to tackle a husky bear or a well-horned stag with only a spear for a +weapon? + +No more did our undressed ancestors. The invention of the greatly +desired arm probably came about in a most curious way. + +Long ages ago man had learned to make fire by patiently rubbing two +sticks together, or by twirling a round one between his hands with its +point resting upon a flat piece of wood. + +[Illustration: THE “LONG BOW” IN SHERWOOD FOREST + +ONE OF ROBIN HOOD’S FAMOUS BAND ENCOUNTERS A SAVAGE TUSKER AT CLOSE +RANGE] + +In this way it could be made to smoke, and finally set fire to a tuft +of dried moss, from which he might get a flame for cooking. This was +such hard work that he bethought him to twist a string of sinew about +the upright spindle and cause it to twirl by pulling alternately at +the two string ends, as some savage races still do. From this it was +a simple step to fasten the ends of the two strings to a bent piece +of wood, another great advantage since now but one hand was needed to +twirl the spindle, and the other could hold it in place. This was the +“bow-drill” which also is used to this day. + +But bent wood is apt to be springy. Suppose that while one were +bearing on pretty hard with a well-tightened string, in order to bring +fire quickly, the point of the spindle should slip from its block. +Naturally, it would fly away with some force if the position were just +right. + +[Illustration: DEER STALKING WITH THE CROSSBOW + +THIS COMPACT ARM WITH ITS SMALL BOLT AND GREAT POWER WAS POPULAR WITH +MANY SPORTSMEN] + +There was one man who stopped short when he lost his spindle, for a +red-hot idea shot suddenly through his brain. + +Once or twice he chuckled to himself softly. Thereupon he arose and +began to experiment. He chose a longer, springier piece of wood, bent +it into a bow, and strung it with a longer thong. He placed the end of +a straight stick against the thong, drew it strongly back, and released +it. + +The shaft whizzed away with force enough to delight him, and lo, there +was the first Bow-and-Arrow! + +Armed with his bow-and-arrow, man now was lord of creation. No longer +was it necessary for him to huddle with his fellows in some cave to +avoid being eaten by prowling beasts. Instead he went where he would +and boldly hunted the fiercest of them. In other words, his brain was +beginning to tell, for though his body was still no match for the lion +and the bear, he had thought out a way to conquer them. + +Also he was better fed with a greater variety of game. And now, free +to come and go wherever he might find it, he was able to spread into +various lands and so to organize the tribes and nations which at last +gave us civilization and history. + +A new weapon now came about through warfare. Man has been a savage +fighting animal through pretty much all his history, but while he tried +to kill the other fellow, he objected to being killed himself. + +Therefore he took to wearing armor. During the Middle Ages he piled on +more and more, until at last one of the knights could hardly walk, and +it took a strong horse to carry him. When such a one fell, he went over +with a crash like a tin-peddler’s wagon, and had to be picked up again +by some of his men. Such armor would turn most of the arrows. Hence +invention got at work again and produced the Crossbow and its bolt. We +have already learned how the tough skin of animals brought about the +bow; now we see that man’s artificial iron skin caused the invention of +the crossbow. + +What was the Crossbow? It was the first real hand-shooting machine. It +was another big step toward the day of the rifle. The idea was simple +enough. Wooden bows had already been made as strong as the strongest +man could pull, and they wished for still stronger ones--steel ones. +How could they pull them? At first they mounted them upon a wooden +frame and rested one end on the shoulder for a brace. Then they took to +pressing the other end against the ground, and using both hands. Next, +it was a bright idea to put a stirrup on this end, in order to hold it +with the foot. + +Still they were not satisfied. “Stronger, stronger!” they clamored; +“give us bows which will kill the enemy farther away than he can shoot +at us! If we cannot set such bows with both arms let us try our backs!” +So they fastened “belt-claws” to their stout girdles and tugged the bow +strings into place with their back and leg muscles. + + + + +Who First Discovered the Power of Gunpowder? + + +Probably the Chinese, although all authorities do not agree. Strange, +is it not, that a race still using crossbows in its army should have +known of explosives long before the Christian Era, and perhaps as far +back as the time of Moses? Here is a passage from their ancient Gentoo +Code of Laws: “The magistrate shall not make war with any deceitful +machine, or with poisoned weapons, or with cannons or guns, or any kind +of firearms.” But China might as well have been Mars before the age of +travel. Our civilization had to work out the problem for itself. + +It all began through playing with fire. It was desired to throw fire on +an enemy’s buildings, or his ships, and so destroy them. + +Burning torches were thrown by machines, made of cords and springs, +over a city wall, and it became a great study to find the best burning +compound with which to cover these torches. One was needed which would +blaze with a great flame and was hard to put out. + +Hence the early chemists made all possible mixtures of pitch, resin, +naphtha, sulphur, saltpeter, etc.; “Greek fire” was one of the most +famous. + +Many of these were made in the monasteries. The monks were pretty much +the only people in those days with time for study, and two of these +shaven-headed scientists now had a chance to enter history. Roger Bacon +was the first. One night he was working his diabolical mixture in the +stone-walled laboratory, and watched, by the flickering lights, the +progress of a certain interesting combination for which he had used +pure instead of impure saltpeter. + +Suddenly there was an explosion, shattering the chemical apparatus and +probably alarming the whole building. That explosion proved the new +combination was not fitted for use as a thrown fire; it also showed the +existence of terrible forces far beyond the power of all bow-springs, +even those made of steel. + +Roger Bacon thus discovered what was practically gunpowder, as far +back as the thirteenth century, and left writings in which he +recorded mixing 11.2 parts of the saltpeter, 29.4 of charcoal, and +29 of sulphur. This was the formula developed as the result of his +investigations. + +Berthold Schwartz, a monk of Freiburg, studied Bacon’s works and +carried on dangerous experiments of his own, so that he is ranked with +Bacon for the honor. He was also the first one to rouse the interest of +Europe in the great discovery. + +[Illustration: THE “KENTUCKY RIFLE” WITH ITS FLINT-LOCK WAS ACCURATE +BUT MUST BE MUZZLE-CHARGED] + +~THE FIRST REAL FIRE ARMS~ + +And then began the first crude, clumsy efforts at gunmaking. Firearms +were born. + +Hand bombards and culverins were among the early types. Some of these +were so heavy that a forked support had to be driven into the ground, +and two men were needed, one to hold and aim, the other to prime and +fire. + +Improvements kept coming, however. Guns were lightened and bettered in +shape. Somebody thought of putting a flash pan, for the powder, by the +side of the touch-hole, and now it was decided to fasten the slow-match +in a movable cock upon the barrel, and ignite it with a trigger. These +matches were fuses of some slow-burning fiber, like tow, which would +keep a spark for a considerable time. Formerly they had to be carried +separately, but the new arrangement was a great convenience and made +the match-lock. The cock, being curved like a snake, was called the +“serpentine.” + +About the time sportsmen were through wondering at the convenience +of the match-lock, they began to realize its inconvenience. They +found that they burned up a great deal of fuse, and were hard to keep +lighted. Both statements were true, so inventors racked their brains +again for something better. They all knew you could bring sparks with +flint and steel, and that seemed an idea worth working on. A Nuremberg +inventor, in 1515, hit on the wheel-lock. In this a notched steel +wheel was wound up with a key like a clock. Flint or pyrite was held +against the jagged edge of the wheel by the pressure of the serpentine. +You pulled the trigger, then “whirr,” the wheel revolved, a stream of +sparks flew off into the flash-pan, and the gun was discharged. + +[Illustration: WHEEL-LOCK RIFLE] + +This gun worked beautifully, but it was expensive. Wealthy sportsmen +could afford them, and so for the first time firearms began to be used +for hunting. Some of these sixteenth and seventeenth century nabobs had +such guns of beautiful workmanship, so wrought and carved and inlaid, +that they must have cost a small fortune. You will find them in many +large museums to this day. + +But now the robbers had their turn. There are two stories of the +invention of the flint-lock. Both deal with robbers, both have good +authority, and both may be true, for inventions sometimes are made +independently in different places. + +One story runs that the flint-lock which was often styled “Lock à la +Miquelet,” from the Spanish word, “Miquelitos”--marauders--told its +origin in its name. The other is, that the flint-lock was invented in +Holland by gangs of thieves, whose principal business was to steal +poultry. + +In either case the explanation is easy. The match-lock showed its fire +at night and wouldn’t do for thieves, the wheel-lock was too expensive, +so again necessity became the mother of a far-reaching invention. + +Everybody knows what the flint-lock was like. You simply fastened a +flake of flint in the cock and snapped it against a steel plate. This +struck off sparks which fell into the flash-pan and fired the charge. + +It was so practical that it became the form of gun for all uses; thus +gunmaking began to be a big industry. Invented early in the seventeenth +century, it was used by the hunters and soldiers of the next two +hundred years. Old people remember when flint-locks were plentiful +everywhere. In fact, they are still being manufactured and are sold +in some parts of Africa and the Orient. One factory in Birmingham, +England, is said to produce about twelve hundred weekly, and Belgium +shares in their manufacture. Some of the Arabs use them to this day in +the form of strange-looking guns with long, slender muzzles and very +light, curved stocks. + +There were freak inventors in the flint-lock period just as there are +to-day. Some of them wrestled with the problem of repeating guns, +and put together a number of barrels, even seven in the case of one +carbine. Others tried revolving chambers, like our revolvers, and still +others, magazine stocks. Pistols came into use in many interesting +shapes, but these were too practical to be considered freaks. + +~WHY WE CALL THEM PISTOLS~ + +Pistols, by the way, are named from the town of Pistola, Italy, where +they are said to have been invented and first used. + +We must not forget that rifling was invented about the time that the +wheel-lock appeared, and had a great deal to do with the improvement +of shooting. Austrians claim its invention for Casper Zollner, of +Vienna, who cut straight grooves in the barrel’s bore. His gun is said +to have been used for the first time in 1498, but the Italians seem +to have still better warrant as these significant words appear in old +Latin Italian, under date of July 28th, 1476, in the inventory of the +fortress of Guastalla: “Also one iron gun made with a twist like a +snail shell.” The rifling made the bullet spin like a top as it flew +through the air, thus greatly improving its precision. + +In the year 1807 the Rev. Alexander John Forsythe, LL.D., got his +patent papers for something far better than even the steady old flint. +He had invented the percussion system. In some form this has been used +ever since. Which is to say that when the hammer of your gun falls, it +doesn’t explode the powder, although it seems to. Instead it sets off a +tiny portion of a very sensitive chemical compound called the “primer,” +and the explosion of this “primer” makes the powder go off. Of course, +the two explosions come so swiftly that your ear hears only a single +bang. + +Primers were tried in different forms called “detonators,” but the +familiar little copper cap was the most popular. No need to describe +them. Millions are still made to be used on old-fashioned nipple guns, +even in this day of fixed ammunition. + +But now we come to another great development, the Breech-loader. + +[Illustration: THE MODERN AUTOMATIC RIFLE + +THE MODERN SPORTSMAN WITH HIS AUTOMATIC RIFLE IS PREPARED FOR ALL +EMERGENCIES] + +Perhaps you have had to handle an old muzzle-loader. It was all right +so long as you knew of nothing better, but think of it now that you +have your beautiful breech-loader. Do you remember how sometimes you +overloaded, and the kick made your shoulder lame for a week? Or how, +when you were excited you shot away your ramrod? The gun fouled too, +and was hard to clean, the nipples broke off, the caps split, and the +breeches rusted so that you had to take them to a gunsmith. Yes, in +spite of the game it got, it was a lot of trouble, now you come to +think of it. How different it all is now! + +[Illustration: ASSEMBLING REPEATING SHOTGUNS AND RIFLES] + +Breech-loaders were hardly new. King Henry VIII of England, he of the +many wives, had a match-lock arquebus of this type dated 1537. Henry IV +of France even invented one for his army, and others worked a little +on the idea from time to time. But it wasn’t until fixed ammunition +came into use that the breech-loader really came to stay--and that +was only the other day. You remember that the Civil War began with +muzzle-loaders and ended with breech-loaders. + +[Illustration: ASSEMBLING AUTO SHOTGUNS] + +[Illustration: SOME OF THE SHOOTING TESTS] + +Houiller, the French gunsmith, hit on the great idea of the cartridge. +If you were going to use powder, ball and percussion primer to get your +game, why not put them all into a neat, handy, gas-tight case? + + +THE FIRST AMERICAN MADE GUNS + +~HOW THE FIRST AMERICAN GUN WAS MADE~ + +Two men, a smith and his son, both named Eliphalet Remington, in +1816, were working busily one day at their forge in beautiful Ilion +Gorge, when, so tradition says, the son asked his father for money to +buy a rifle, and met with a refusal. The request was natural for the +surrounding hills were full of game. The father must have had his own +reasons for refusing, but it started the manufacture of guns in America. + +Eliphalet, Jr., closed his firm jaws tightly, and began collecting +scrap iron on his own account. This he welded skillfully into a +gun-barrel, walked fifteen miles to Utica to have it rifled, and +finally had a weapon of which he might well be proud. + +[Illustration: TYPES OF CARTRIDGES] + +In reality, it was such a very good gun that soon the neighbors ordered +others like it, and before long the Remington forge found itself hard +at work to meet the increasing demand. Several times each week the +stalwart young manufacturer packed a load of gun-barrels upon his back, +and tramped all the way to Utica where a gunsmith rifled and finished +them. At this time there were no real gun-factories in America, +although gunsmiths were located in most of the larger towns. All +gun-barrels were imported from England or Europe. + + +A VISIT TO A CARTRIDGE FACTORY + +~HOW AMMUNITION IS MADE~ + +One of the first shocks you get when you start your visit through a +cartridge factory is the matter-of-fact way in which the operatives, +girls in many cases, handle the most terrible compounds. We stop, for +example, where they are making primers to go in the head of your loaded +shell, in order that it may not miss fire when the bunch of quail +whirrs suddenly into the air from the sheltering grasses. That grayish +pasty mass is wet fulminate of mercury. Suppose it should dry a trifle +too rapidly. It would be the last thing you ever did suppose, for there +is force enough in that double handful to blow its surroundings into +fragments. You edge away a little, and no wonder, but the girl who +handles it shows no fear as she deftly but carefully presses it into +moulds which separate it into the proper sizes for primers. She knows +that in its present moist condition it cannot explode. + +[Illustration: INSPECTING METALLIC SHELLS] + +[Illustration: EXAMINING PAPER SHELLS] + +[Illustration: WEIGHING BULLETS] + +Or, perhaps, we may be watching one of the many loading machines. +There is a certain suggestiveness in the way the machines are separated +by partitions. The man in charge takes a small carrier of powder from a +case in the outside wall and shuts the door, then carefully empties it +into the reservoir of his machine, and watches alertly while it packs +the proper portions into the waiting shells. He looks like a careful +man, and needs to be. You do not stand too close. + +[Illustration: SHOOTING ROOM OF BALLISTICS DEPARTMENT] + +[Illustration: CHRONOGRAPH FOR MEASURING] + +The empty carrier then passes through a little door at the side of the +building, and drops into the yawning mouth of an automatic tube. In the +twinkling of an eye it appears in front of the operator in one of the +distributing stations, where it is refilled, and returned to its proper +loading machine, in order to keep the machine going at a perfectly +uniform rate; while at the same time it allows but a minimum amount +of powder to remain in the building at any moment. Each machine has +but just sufficient powder in its hopper to run until a new supply can +reach it. Greater precaution than this cannot be imagined, illustrating +as it does that no effort has been spared to protect the lives of the +operators. + +[Illustration: PUTTING METAL HEADS ON PAPER SHOT SHELLS] + +It is remarkable that, in an output of something like four million per +day, every cartridge is perfect. + +Such things are not accidental. The secret is, inspection. + +~TESTING MATERIALS AND PRODUCTS~ + +Let us see what that means. It means laboratory tests to start with. +Here are brought many samples of the body paper, wad paper, metals, +waterproofing mixture, fulminate of mercury, sulphur, chlorate of +potash, antimony sulphide, powder, wax, and other ingredients, and +even the operating materials such as coal, grease, oil, and soaps. +In the laboratory we see expert chemists and metallurgists with +their test-tubes, scales, Bunsen burners, retorts, tensile machines, +microscopes, and other scientific looking apparatus, busily hunting +for defects. + +For example, one marker is examining a supply of cupro-nickel, such as +is used in jacketing certain bullets. A corner of each strip is first +bent over at right angles, then back in the other direction until it +is doubled, then straightened. It does not show the slightest sign of +breaking or cracking, in spite of the severe treatment, therefore it is +perfect. Let but the least flaw appear, and the shipment is rejected. + +[Illustration: WHAT A SHOT TOWER LOOKS LIKE + + SHOT TOWER--TALLEST BUILDING IN CONNECTICUT] + +[Illustration: + + LARGEST CARTRIDGE EQUALS MORE + THAN 1,000,000 OF SMALLEST + (HELD ON HAND)] + +Two large iron cylinders descend in the center, coming down through the +ceiling from above; we are invited to look through an open port in one +of these. + +We see nothing but the whitened opposite wall, against which a light +burns. + +It appears absolutely empty, though within it is raining such a swift +shower of invisible metal that if we were to stretch our hands into the +apparently vacant space they would be torn from our arms. + +A large water tank below is churned into foam with the impact of the +falling shot, and as we look downward we make out finally the haze of +motion. It is so interesting that we take the elevator and rise ten +stories to the source of the shower. + +Here high in the air are the large caldrons where many pigs of lead, +with the proper alloy, are melted into a sort of metallic soup. This +is fed into small compartments containing sieves or screens, through +the meshes of which the shining drops appear and then plunge swiftly +downward. + +But this only begins the process. Taken from the water tanks and +hoisted up again, the shot pellets, in a second journey down, through +complicated devices, are sorted, tumbled, polished, graded, coated with +graphite, and finally stored. + + The pictures shown in this story were prepared especially to + illustrate this story of “How Man Learned to Shoot” by the + Searchlight Library for the Remington Arms Company. + +[Illustration: FORGING A MONSTER GUN + + Photo by Bethlehem Steel Co. + +This photograph shows gun ingots after being “stripped” and “cored.”] + +[Illustration: + + Photo by Bethlehem Steel Co. + +This photograph shows a gun ingot in the process of being forged under +forging press.] + +[Illustration: + + Photo by Bethlehem Steel Co. + +This photograph shows a gun being fired at the Proving Grounds for +test.] + + + + +The Parts of a Big Gun + + +~THINGS TO KNOW ABOUT A BIG GUN~ + +Before going into a description of the manufacture of a big gun it +would be well to understand the following definitions: + +The “breech” of a gun is its rear-end, or that end into which the +projectile and powder charge are loaded. + +The “muzzle” of a gun is its forward end. + +By “calibre” is meant the inside diameter of the gun in inches. A +5-inch gun is one of “minor calibre,” and one of 14-inches a gun of +“major calibre.” + +The length of a gun is never expressed in inches or feet, but in the +_number of times_ that its calibre is divisible into its length; thus, +when we say a 12-inch 50-calibre gun, we mean a gun of 12 inches in +diameter, and 12 times 50, or 600 inches long. + +The “bore” is the hole extending through the center of the gun, from +the rear face of the liner to its forward end. + +The “powder chamber” is the rear part of the bore, and extends from the +face of the breech plug when closed to the point where the “rifling” +begins. The powder chamber is slightly larger in diameter than the rest +of the bore. + +The “rifling” is the name given to the spiral grooves which are cut +into the surface of the bore of the gun, and give to the projectile its +rotary motion when the gun is fired. + +With the advent of “iron-clads” and heavily armored fortresses, it +became necessary to increase the power of the guns in use, until to-day +a 14-inch gun of 45 calibres fires a projectile weighing 1400 pounds, +with an initial velocity of 2600 feet per second. An idea of this +initial velocity may be better obtained by comparison when you realize +that a train going sixty miles an hour is only traveling at the rate +of 88 feet per second. Now, in order to produce such wonderful power in +a gun, great pressure must be generated in the bore, and it was soon +found that a one-piece gun, whether cast or forged, could not withstand +such pressures. + +To begin with, we may consider this one-piece gun, or any gun, as a +tube which must withstand a great pressure from within, so that when +a gun is designed care must be taken to see that the material from +which it is constructed is strong enough to withstand this pressure. +And not only must the gun be sufficiently strong, but it must not +be too heavy, so that you see you cannot go on forever increasing +the thickness of the walls of this tube. Besides, it is generally +acknowledged that a simple tube or cylinder cannot be made with walls +of sufficient thickness to withstand from within a _continued_ pressure +per square inch greater than the tenacity of a square-inch bar of the +same material; in other words, if the tensile strength of a metal is +only twelve tons per square inch, no gun of that metal, however thick +its walls, could withstand a pressure of twenty tons per square inch, +and the modern big guns are tested at that great a pressure. And if we +look further into this matter of pressures we find that when a gun is +fired the pressure exerts itself in two ways; it tends to burst the gun +longitudinally or down the middle, and it tends to pull the gun apart +in the direction of its length. Of course, some method of strengthening +this one-piece gun was sought after, with the result that to-day guns +are either “_built-up_” or “_wire-wound_.” + +A “built-up” gun is one made of several layers, each layer being +separately constructed and then assembled together. The order of +assemblage differs somewhat with the different calibres, but the method +of assemblage is essentially the same, that is, the outside layers are +heated and shrunk on the inner ones. This question will be treated at +greater length later on. + +A “wire-wound” gun is one in which the necessary additional strength +is obtained by winding wire around an inner tube of steel, each layer +being wound with a different tension of the wire; this type of gun +has found great favor with foreign manufacturers. In this country, +however, the “built-up” system is used almost exclusively, and so this +description will deal with the manufacture of a “built-up” gun. + +[Illustration: HOW A BIG GUN WOULD LOOK IF YOU WERE TO CUT IT IN TWO + +Sketch Showing Construction of a Modern “Built-up” Gun. + +_A_, HOOP; _B_, HOOP; _C_, JACKET; _D_, TUBE; _E_, LINER; _F_, HOOP.] + +A modern “built-up” gun is composed of a _liner_, a _tube_, a _jacket_ +and _hoops_. + +The _liner_ is in one piece and extends the entire length of the bore +and carries the “rifling” and the powder chamber. + +The _tube_ is in one piece and envelops the liner for its entire +length. Formerly the _tube_ carried the “rifling” and powder chamber, +but due to the wearing out of the “rifling” with constant firing, a +liner was decided on, so that now when the “rifling” becomes worn, the +liner can be removed and a new one substituted. + +The _jacket_ is usually in two pieces and is shrunk on the tube; it +extends the entire length, and its rear end is threaded in the inside +for the attachment of the “breech bushing.” + +_Hoops_ are shrunk on over the jacket and in a big gun are sometimes as +many as six or seven in number. + +The liner, tube, jacket and hoops are made of the finest quality of +open hearth steel, and the steel must conform to specifications set by +the government. + +[Illustration: + + Photo by Bethlehem Steel Co. + +This photograph shows a mould for a gun ingot under hydraulic press for +fluid compression.] + +The chemical composition having been determined, the necessary elements +are weighed out and the whole charged into an open hearth furnace. When +the furnace is ready to be tapped the molten metal is run into a large +ladle, which in turn is taken by a crane to the casting pit, where the +mould is filled. The ingots for the large calibre guns run from 42-inch +to 48-inch in diameter, and after being poured they are immediately +run under a hydraulic press, where they are subjected to a pressure +of about six tons per square inch to drive out the gases, and then +lowered to about 1500 pounds pressure per square inch for a certain +length of time during the cooling. This pressure tends to make the +ingot solid, by expelling the gases, which would cause blow-holes, and +by preventing “piping” and “segregation.” When a metal cools, the top +and sides cool first, and this outer layer shrinks and pulls away from +the centre, with the result that a cavity or “pipe” would be formed, +but the hydraulic pressure forces fluid metal into this cavity and +so prevents the “pipe.” The cooling also causes the various elements +to solidify separately, and they tend to break away from the mass +and collect at the centre; this is called “segregation,” and is also +partially prevented by fluid compression. A solid ingot, however, is +obtained, and this is absolutely necessary. + +After the ingot has cooled sufficiently it is “_stripped_,” that is, +it is removed from the mould, and then it is sent to the shop to have +the “discard,” or extra length, cut off. When the ingot is cast, an +extra amount of metal is poured into the mould to permit this discard, +the theory being that the poorer metal, together with gases and other +impurities, rise to the top. The government specifications require that +there shall be a 20% discard from the upper end and a 3% discard from +the lower end. The discard having been cut off, the ingot is “cored,” +that is, its centre is bored out, the diameter of the hole depending on +the size of the ingot. + +[Illustration: TAKING THE BORE OF A BIG GUN + + Photo by Bethlehem Steel Co. + +This photograph shows gun ingot in boring mill being cored.] + +The ingot is now ready for the “forge,” and on its receipt in the forge +shop it is placed in a furnace to be heated; and here great care must +be exercised to prevent setting up any additional strains in the ingot. +When the ingot was cooling just after casting the metal tended to flow +from the centre; the interior is still in a condition of strain, and if +the cold ingot is now placed in a hot furnace, cracks are apt to form +in the centre, causing the forging to later break in service. + +However, the ingot having been properly heated, it is ready for either +the forging hammer or the press. The present-day practice, though, is +to forge the ingot under a press forge, as the working of the metal +causes a certain flow, and as a certain amount of time is necessary +for this flow, the continued pressure and slow motion of the press +allows the molecules of the metal to adjust themselves more easily, +and a better and more homogeneous forged ingot is produced than if the +forging had been done with a hammer. + +When forging a hollow ingot, a mandrel, merely a cylindrical steel +shaft, is placed through the hole in the ingot and the ingot forged +on the mandrel, thereby not only is the outside diameter of the ingot +decreased, but the length of the ingot is increased. The usual practice +is to continue the forging until the original thickness of the walls +of the ingot is decreased one-half and until the ingot is within two +inches of the required finished diameters. The ingot is now known as a +“forging,” and the lower end of each ingot as cast will be the breech +end of the forging that is made from it. + +The next process is that of “annealing.” This consists in heating the +forging to a red heat and then allowing it to cool very slowly, and +is usually done by hauling the fires in the furnace after the correct +temperature has been attained and permitting both to cool off together. +This process is to relieve the strains set up in the metal during +forging, and further, it alters the molecular condition of the steel, +making a finer and more homogeneous forging. + +[Illustration: HOW THE GUN TUBE IS TEMPERED + + Photo by Bethlehem Steel Co. + +This photograph shows a gun tube ready to be lowered into oil bath for +“oil tempering.”] + +After annealing, the forging is ready to go to the machine shop to +be rough bored and turned. The forging is set in a lathe, the breech +end being held by jaws on the face-plate and the muzzle end by a +“pot-centre,” a large iron ring having several radial arms screwed +through it. The lathe can now be turned and the forging centered by +screwing in or out on the jaws of the face-plate or the radial arms of +the “pot-centre.” When centered, several surfaces are turned on the +forging for “steady rests” and then all is in readiness for the turning +and boring. + +In both operations of “turning” and “boring,” the work revolves while +the cutting tools are fed along. Turning is very simple and usually +several tools are cutting at the same time, but boring is a more +delicate operation, because the workman cannot see what he is doing. +And in boring, either a “hog bit” or a “packed bit” is used; a “hog +bit” is a half cylinder of cast iron fitted with one cutting tool and +used for rough cuts, while a “packed bit” is a full cylinder of wood +with metal framing and carrying two tools 180° apart and used for +finishing cuts. + +The forging, having been rough machined, is now ready to receive its +heat treatment in order to give to the steel its required physical +characteristics. Every piece of steel used in gun manufacture must +conform to certain specifications as regard both its physical and +chemical characteristics. The chemical analysis was made at the time +the ingot was cast; now for the treatment of the forging, prior to the +physical test as to its tensile strength, elastic limit, elongation and +contraction. + +The “tensile strength” of a metal is the unit-stress required to break +that metal into parts. If a round bar ten inches in cross-section area +will fracture under a strain of 120 tons, its tensile strength is 120 ÷ +10 or 12 tons per square inch. Tensile strength is usually expressed in +pounds per square inch. + +The “elastic limit” of a metal is the unit-stress required to first +produce a permanent deformation of the metal. If a bar of metal be +subjected to an increasing strain, up to a certain point that metal +will be perfectly elastic, resuming its normal shape when the strain +is removed; at the first permanent set or deformation, however, +the elastic limit of that metal has been reached. Elastic limit is +expressed in pounds per square inch. + +By “elongation” is meant the increase in length in a bar when its +tensile strength is reached. If a bar 10 inches long after rupture +measures 11.8 inches, its elongation is 18%. + +By “contraction” is meant the decrease in cross-section area in a bar +when its tensile strength is reached. If a bar 1 square inch in area +after rupture is only .75 of a square inch in area, its contraction is +25%. + +These definitions being understood, a brief description of the heat +treatment can be taken up, because it is after this treatment that +standard bars are taken from the forgings to undergo the physical +tests. The first step consists in “tempering” or hardening the metal. +The piece to be tempered is placed in an upright position in a high +furnace and uniformly heated to the required temperature. It is then +lifted from the furnace through an opening in the top and carried by a +crane to an oil tank of suitable depth and plunged into the oil. This +rapid cooling or “tempering in oil” is facilitated by having the oil +tank surrounded by a water bath, so arranged that a supply of cold +water is constantly in circulation to carry the heat from the mass +as quickly as possible. This operation produces exceeding toughness, +increases the tensile strength and raises the elastic limit of the +metal. + +Now the forging is again annealed, so as to relieve any strains set +up by tempering and to soften up the metal to the degree required by +the specifications. It also increases materially the elongation and +contraction. Great care must be exercised in the heat treatment, as the +acceptance or rejection of the forging depends upon whether or not the +test bars pass the required specifications. + +The forging is now submitted for test and the test bars taken. In the +manufacture of a big gun, four test bars are taken from the breech +end and four from the muzzle end of each forging and these bars +sent to the physical laboratory. Quite an elaborate testing machine +is provided, and if the bars pass the required tests the forging is +accepted and is sent to the machine shop for finish-boring and turning. + +~SEARCHING FOR POSSIBLE DEFECTS~ + +Frequently during finish-boring the work is examined to see that the +bit is running true, and great care must be exercised to prevent its +running out of alignment. + +After finish-boring every forging is “bore-searched,” that is, the bore +is carefully examined for any cracks, flaws, streaks or discoloration. +A special instrument called a “bore-searcher” is used and consists of +a long wooden handle which has a mirror inclined at 45° at one end, +together with a light to illuminate the bore, and so shielded as to +obscure the light from the observer. (See sketch.) + +[Illustration] + +The bore is also inspected by the foreman after each boring, but the +final “bore-searching” is done by an inspector. + +Now to measure accurately the inside diameters of long cylinders, +such as are used in gun work, a special measuring device called a +“star-gauge” is used. Its name is derived from the fact that it has +three measuring points set at 120° apart and two measurements are +taken, one [Illustration] and the other [Illustration], making a star +[Illustration]. Every forging is “star-gauged” after being finish-bored +and also the liner of the _gun_ after each assemblage operation. + +~PUTTING THE PARTS OF A “BUILT-UP” GUN TOGETHER~ + +In preparation for the assembling of the different parts, the tube is +the forging to be finished. It is bored and turned to exact dimensions +and carefully “bore-searched” and “star-gauged.” With the data at hand +a sketch is made showing the external diameters of the liner under the +tube, due allowance being made for the shrinkage when assembling. + +The liner is next bored to within .35 of an inch of the finished +diameter, and turned to the dimensions required by the sketch above. +This extra metal in the bore is left until the gun is completely +assembled and is removed in the finish-boring. The liner is then +carefully “bore-searched” and “star-gauged” and liner and tube are +ready for assembling. + +The liner is now taken to the shrinking pit and carefully aligned in an +upright position with the breech end down. + +The shrinking pit is merely a well of square section with room enough +to permit workmen to move freely about the gun when it is in position, +and equipped with a movable table at its bottom upon which the gun +rests. In the meantime the tube, with breech end down, is being heated +in a hot-air furnace. This furnace is a vertical cylinder built of +fire-brick and asbestos and so constructed that air which has been +passed in pipes over petroleum burners can enter at the bottom, pass +around and through the tube and out through the top to be reheated. +This service permits a uniform heat to be transmitted to the tube and +when the desired temperature has been attained the tube is lifted from +the furnace by a crane, carried to the shrinking pit and carefully +lowered over the liner. Great care must be exercised in this operation +to prevent the tube from sticking while being lowered into place. +Should it happen, the tube should be hoisted off at once, allowed to +cool, any roughing of the liner be smoothed off, the tube reheated and +a second trial made. When the tube is properly in place a cold spray +may be turned upon any particular section where it is desired the tube +should first grip the liner. The tube is then left to cool by itself, +but cold water is constantly circulating through the liner. + +When the gun is sufficiently cool for handling purposes, it is hoisted +out of the shrinking pit and taken to the shop for careful measurement, +the liner being “star-gauged” to note the compression due to the +shrinking on of the tube. + +The same procedure is followed in the case of the jackets and hoops, +until the entire gun is assembled. The gun is considered completely +“built-up” when the last hoop has been shrunk on and is now ready to be +finished. + +The gun is now finish-bored, as .35 of an inch of metal was left in the +liner in the first boring. “Packed bits” are used and the greatest care +is exercised to keep the bit properly centered and running true. After +this step the gun is finish-turned and the powder chamber is bored. + +Following this operation the gun is “bore-searched” for any defects +that may have shown up in the finish-boring and chambering, and then +carefully “star-gauged.” The gun is then ready to be “rifled.” + +[Illustration: RIFLING A BIG GUN + + Photo by Bethlehem Steel Co. + +This photograph shows a gun in the Rifling Machine in the process of +being rifled.] + +The “rifling” of a gun consists in cutting spiral grooves in the +surface of the bore from the powder chamber to the muzzle end, and is +done from the muzzle end. Rifling is a very difficult operation, and +great care must be exercised that the cutting is uniform. The grooves +are separated by raised portions called “lands,” and after “rifling,” +these grooves and “lands” are carefully smoothed up to remove the rough +edges or burrs caused by the cutting tools of the “rifling” machine. + +The necessary holes are now drilled for fitting the breech mechanism +and the breech block fitted. This operation usually takes some little +time, as quite a bit of hand work is necessary to insure a perfect fit. +The “yoke,” really another “hoop,” is now put on at the breech end and +the gun is complete. + +The centre of gravity of gun and breech mechanism is now determined +by balancing on knife edges and the whole then weighed. The breech +mechanism is also weighed and the two weights marked on the rear faces +of the gun and breech mechanism. + +The gun is now fitted in its “slide,” that part of the mount which +carries the trunnions and through which the gun recoils when it +is fired, and after it is adjusted, all is in readiness for the +“proof-firing” or testing of the gun. + + + + +What Is Motion? + + +There are practically but two things we see when we use our eyes. +One of them is matter, which is a term we apply to the things we +see, speaking of them as objects only, and the other is motion which +we observe some of the matter to possess. Some of the things we see +confuse us, if we bear in mind that everything is either matter or +motion. For instance, we see light and know it is not matter and are +confused until we understand that light is a movement of the ether +which surrounds us and is in and outside of everything. In the same way +we feel heat and may think it is matter thrown off by the fire, when it +is only another kind of motion of this same ether. When we understand +these things we see that motion is a very important and real part of +the world. + +When a motion is started it will keep on going forever unless some +other force which is able to overcome the motion stops it. When a ball +is thrown in the air it would go on forever were it not for the law of +gravitation which pulls it to the earth and the friction of the air on +the ball as it goes through the air. When you stop a thrown ball you +sometimes realize that motion is a real thing because it stings your +hands. We do wonderful things with motion. Many things when you add +motion to them acquire qualities which they did not possess before. For +instance, an ordinary icicle thrown against a wooden door will break, +but if you put it into a gun and give it sufficient motion, it will go +right through the door. There is a story of how a man killed another +by using an icicle as a bullet. The icicle entered the man’s body and +killed him. Then, of course, the ice melted and no one could tell how +the man received his wound, for no trace of anything like a bullet +could be found. A piece of paper has no cutting qualities, but if you +arrange a circular or square piece of paper with a rod or stick through +the center and revolve it fast enough, you can cut many things while it +is whirling. The motion gives it the cutting qualities. You can take a +piece of strong rope and, by tying the ends together, making a circle +of it, you can make it roll down the street like a steel hoop if you +catch it just the right way and set it spinning fast enough before +starting it on its way. A steam engine has no power to pull the train +of cars until the wheels are set in motion. So we see that motion is a +very important thing in the world. + +Motion is the cause of movements of all kinds, the power which takes +things from one place to another. + + + + +Is Perpetual Motion Possible? + + +Perpetual motion will never be possible unless some one discovers a +way to overcome the law of gravitation and also the certainty that +materials will eventually wear out. Many men have tried to make a +machine that would keep on moving forever without the application of +any power, the consumption of fuel within itself, the fall of weights +or the unwinding of a spring; such a machine would be absolutely +impossible, although many people have been fooled into investing money +in machines that appeared to have this power within themselves. + + + + +How Can an Explosion Break Windows That Are at a Distance? + + +An explosion is a sudden expansion of a substance like gunpowder or +some elastic fluid or other substance that has the power to explode +under certain conditions with force, and usually a loud report. Some +explosions are comparatively mild and accompanied by a very mild noise, +while others are very powerful and accompanied by a very loud noise. +When an explosion occurs, the air and everything surrounding the thing +that explodes is very much disturbed. The air surrounding the thing +that explodes is thrown back in air waves which are powerful in the +exact proportion in which the explosion is powerful. These air waves +can be so suddenly thrown back against the objects in the vicinity that +not only the windows in the buildings are broken, but often the entire +building blown away. The explosion acts in all directions at once +with equal force. A great hole may be torn in the earth beneath the +explosion. If there is anything over the explosion, that is blown away +unless its power of resistance is sufficient to withstand the power of +the explosion. Then, also, the air surrounding on all sides is forced +back against everything in its path. + +Very often this air which is suddenly forced back by the power of the +explosion is thrown against houses at a distance. These houses may +be so strongly built as to be able to withstand the effect of the +explosion, but still certain parts of them, such as the windows and +the bricks of the chimney, may not be able to withstand this sudden +pressure of air against them and they are forced in. The wind from such +an explosion acts on the outside of the windows just the same as though +you stood on the outside with your hands against the windows and pushed +them in. Anything that is thrown against a window with more force than +the window glass can resist will break the window, and even slight +explosions may be so powerful as to throw the air back and away from +them with such force as to break windows at a great distance--even a +mile or more away. + + + + +Why Do Some Things Bend and Others Break? + + +When an outside force is applied to some objects, some of them will +bend and others break. It is due to the fact that in some things the +particles have the faculty of sticking together or hanging on to each +other, and it is very difficult to break them away from each other. In +such instances, as in the case of a wire, the article will bend when +we apply the power to it and it will not break, because the particles +which make up the wire have the faculty of hanging on to each other. A +piece of glass, however, can be broken right in two by the application +of no more force than was used to bend the wire, because the particles +which make up the glass haven’t the faculty to hang on to each other. +If you continue to bend a wire back and forth, however, at the same +point, it will finally break apart, because you eventually overcome the +ability of the particles in the wire to hang on to each other. + +It all depends upon the hanging-on ability. Sometimes in undergoing +different processes an article which will ordinarily only bend will +become very brittle or breakable. A steel wire may bend but if you make +a steel wire very hard it becomes brittle. On the other hand, glass is +very brittle ordinarily, but if you make it very hot, you can bend it +into any shape you wish, and thus the glass-worker makes different +shapes to various dishes; lamp chimneys, bottles, etc., by heating +glass and then bending it. When it becomes cool again, it also becomes +brittle or breakable as before. + + + + +Why Does a Ball Bounce? + + +When you throw a ball against the floor in order to make it bounce the +ball gets out of shape as soon as it comes in contact with the floor. +As much of it as strikes the floor becomes perfectly flat, and because +the ball has a quality known as elasticity, which means the ability to +return to its proper shape, it returns to its shape immediately and in +doing so forces itself back into the air and that is the bounce. + +Of course, the first thing we think of when we consider something +that bounces is a ball, and in most cases a rubber ball. We are more +familiar with the bouncing qualities of a rubber ball. Other balls, +like standard baseballs, are not so elastic as a rubber ball filled +with air, but a solid-rubber ball is more elastic and some golf balls +are much more elastic than a solid-rubber ball. The principle is the +same, when you drive a golf ball, excepting that when you bounce a ball +on the floor the floor does the flattening and when you drive a golf +ball, the golf club does the flattening. A baseball flies away from the +bat for the same reason. When you meet a fast-pitched ball squarely on +the nose with a good swing, it goes farther and faster than when you +hit a slow-pitched ball with an equal swing, because in the case of the +fast-pitched ball you flatten the ball out more, and it has so much +more to do to recover its proper shape that it bounces away from the +bat at much greater speed and goes much further unless caught than a +slow-pitched ball under the same circumstances. + + + + +What Makes a Ball Stop Bouncing? + + +A bouncing ball, when you first throw it against the wall bounces back +at you about as fast as you throw it, but if you do not catch it on the +rebound, it goes to the floor again, because the law of gravitation +which is the pulling power of the earth, pulls it down again. When it +strikes the floor it is again flattened to a certain extent and bounces +up again, but does not come back so high. It goes on striking the floor +and bouncing back into the air again each time a shorter distance, +until the force of gravity has actually overcome its tendency to bounce +back. + +When you bounce a ball on the floor and it bounces up again, the motion +of the ball through the air is affected by the friction that the +contact with the air produces and this friction of the air overcomes +part of the bouncing ability in the ball also. + + + + +What Makes a Cold Glass Crack if We Put Hot Water Into It? + + +Hot water will not always cause a cold glass to crack, but is very apt +to, especially a thick glass. The very thin glasses will not crack. The +test tubes used by chemists are made of very thin glass, and will not +crack when hot liquids are poured into them. + +When a glass cracks after you have poured a hot liquid into it, it does +so because, as soon as the hot liquid is put in, the particles of glass +which form the inside of the glass become heated and expand. They begin +to do this before the particles which form the outside of the glass +become heated, and in their efforts to expand the inside particles of +glass literally break away from the particles which form the outside, +causing the crack. The same thing happens if you put cold water into a +hot glass, excepting in this instance the inside particles of the glass +contract before the particles which form the outside of the glass have +had time to become cool and do likewise. + + + + +What Causes the Gurgle When I Pour Water from a Bottle? + + +The air trying to get in causes the gurgle. Air has one strong +characteristic which stands out above everything else. It wants to go +some place else all the time. When it learns of a place where there +is no air it wants to go there above all things, and goes at it with a +rush. + +Now, when you turn a bottle full of water upside down, the water comes +out if the cork is out, of course, and as soon as the water starts out +the air strives to get in, and every time you hear a gurgle you know +the air is getting in. Every gurgle is a battle between the water and +the air. Sometimes the air comes and pushes the water back enough to +let it slide into the bottle; sometimes the water pushes the air back, +and thus they fight back and forth. The water always gets out and the +air always gets in. In doing so they make the gurgle. + + + + +Where Does the Part of a Stocking Go That Was Where the Hole Comes? + + +Perhaps this is a foolish question, but many boys and girls have been +puzzled for an answer to it. When you put your stockings on they have +no holes in the feet, and at night, when you take them off, there are +often quite large holes in them. The answer is the same as in the case +of the lead in the lead-pencil. The lead in the pencil wears away. You +can see it wear away because that is what makes the marks. + +When a hole is coming into your stocking, the stocking on your foot +is being rubbed between your foot and something else (probably some +part of your shoe) and this constant rubbing will wear through the +yarns with which the stocking is knitted. Of course, the yarns in +the stocking are stretched somewhat when it is on your foot and the +rubbing finally cuts through the threads and releases the tension of +the threads of yarn, so that not always is as much stocking lost as +the size of the hole. But, if you were to look carefully at your foot +and inside your shoe, when you first take the stocking off and see the +hole, you would find little particles of yarn all about. + + + + +Why Do Coats Have Buttons On the Sleeves? + + +The practice of putting buttons on coat sleeves, which serve no useful +purpose at all and do not add to the beauty of the coat, is a relic of +very old days. + +There was a time when people did not use handkerchiefs, and it was +common practice for men to wipe their noses on their sleeves. They had +coats also in those days, but they did not have buttons on the sleeves. +One of the old kings finally developed the idea of dressing his +soldiers in fancy uniforms and, as he sat in his palace and reviewed +his troops, he noticed many of them using the sleeves of their coats as +handkerchiefs. He immediately issued a decree that all sleeves should +have a row of buttons sewed on them, but at a point directly opposite +to where they are now on the sleeves. This was done to remind the +soldiers that the sleeves of their beautiful uniforms were not to be +used as handkerchiefs, and those who attempted to draw their sleeves in +front of the nose were quickly reminded of the decree by the buttons +which scratched them. And so the buttons really had a quite useful +purpose at one time, and so also all sleeves had buttons sewed on to +them at this place. Later on, however, when the unsightly practice had +been cured and people had learned to use handkerchiefs, the buttons +remained as a decoration, but their former purpose was lost sight of. +Then some tailor or leader of fashion had the buttons set on the under +side of the sleeves for a change, and it became the fashion to have +them there, and the tailors have been sewing them there ever since. + + + + +Why Has a Long Coat Buttons on the Back? + + +The buttons on the back of a long coat, i. e., one with skirts, had a +more sensible reason originally. At one time the skirts of such coats +were made very long, and when the wearer moved quickly the tails of +the coat flapped about the legs and interfered with progress. So an +ingenious gentleman had buttons sewed on to the back and buttonholes +made in the corner of his coat-tails. Then when he was in a hurry he +simply buttoned up his skirts and went his way comfortably. + +[Illustration: TELEPHONE DISPLAY BOARD + +Showing in outline the apparatus necessary to complete the simplest +kind of a telephone call--to a number in the same exchange] + + + + +The Story in the Telephone + + +~WHAT HAPPENS WHEN WE TELEPHONE~ + +Mrs. Smith, at “Subscriber’s Station No. 1,” desires to telephone +to Mrs. Jones at “Subscriber’s Station No. 2.” When she lifts her +receiver, the movement causes a tiny white light to appear instantly on +the switchboard at the Central Office. Directly beneath this light is +another and larger lamp, which glows in a way to attract the operator’s +attention immediately. + +The operator inserts a “plug” in a little hole on the switchboard +called a “jack,” directly above the tiny light which appeared when Mrs. +Smith lifted the receiver. This connects her to Mrs. Smith’s line. Then +she pushes a listening key on the board, connecting her telephone set +to the line. “Number, please?” she calls. + +Mrs. Smith gives the number; the operator repeats it to be sure there +is no mistake, places another “plug” in a “jack” corresponding to the +number of Mrs. Jones’ telephone and makes the connection. + +Each subscriber’s telephone has a particular signal on the switchboard +to which it is connected by a pair of wires. Mrs. Smith’s wires run +from her instrument to the nearest “cable terminal,” a gathering point +for the wires of various telephones in her neighborhood. Here they form +part of a group of wires going to the Central Office. These groups, +called cables, are made up of from 50 to 600 pairs of wires, according +to the telephone needs of the district the “terminal” serves. + +When the wires reach the Central Office they pass through the “cable +vault” to the “main distributing frame,” which is the Central Office +terminal of the cable. + +When the wires come to this frame they are in numbered order in the +cable. Subscribers living next door to Mrs. Smith may have entirely +different call numbers and yet use consecutive wires. It is the task +of the main frame to redistribute these wires, so that they will be +arranged according to their call numbers and to make it possible to +connect Mrs. Smith’s line with the line of any other subscriber with +the least possible delay. This frame has two parts: the “vertical +side” and the “horizontal side.” Before the wires are redistributed +they are taken to pairs of springs equipped with devices for protecting +the lines against outside currents. + +[Illustration: ASKING FOR A NUMBER] + +After leaving the main frame they are taken to the “intermediate +distributing frame,” the central connecting point for various branches +of the lines going to the switchboard, signaling and other apparatus. +From the “horizontal side” of this frame, wires go to the switchboard, +where they terminate in little holes known as “multiple jacks.” They +also connect with the line and position message registers, where the +calls from each Line and the calls handled at each operator’s position +at the switchboard are recorded. The “multiple jacks” are additional +terminals placed at necessary intervals throughout the switchboard, +where they can be used by operators to make connections with any other +line on the board. + +From the “vertical side” of the intermediate frame Mrs. Smith’s wires +reach the “line and cut-off relay,” an electrically controlled switch +which turns on the light signal that appears on the switchboard +when she lifts the receiver from the hook. This “line relay” also +extinguishes the light when the operator makes the connection, or when +Mrs. Smith returns the receiver to the hook. + +[Illustration: A TYPICAL POLE LINE, WITH CROSS ARMS, IN THE COUNTRY] + +The swift moving electric current that was set in motion when Mrs. +Smith began the call, instantaneously passes through all these devices +for safeguarding and protecting the subscriber’s telephone service. The +light announcing Mrs. Smith’s desire to make a call is called the “line +lamp,” and is flashing on the switchboard. Directly beneath it is the +“pilot lamp,” which glows whenever any “line lamp” lights. With the +“line lamp” is a “jack” or terminal, where connection can be made with +Mrs. Smith’s line. This is the “answering jack.” + +[Illustration: THE CABLE VAULT INTO WHICH THE CABLES PASS WHEN THEY +ENTER THE EXCHANGE AND FROM WHICH THEY ARE LED UPWARD TO THE MAIN +DISTRIBUTING FRAME] + +When the operator sees the flashing signal of Mrs. Smith’s “line lamp,” +she inserts one end of a pair of “connecting cords,” which are on +the board before her, in the “answering jack” for Mrs. Smith’s line. +These “connecting cords” are flexible conductors that put the wires +of subscribers in electrical connection. Then she pushes forward the +“operator’s key” directly in front of her and is connected with Mrs. +Smith’s line. + +The operator ascertains the number wanted and places the other +“connecting cord” in the “jack” corresponding to Mrs. Jones’ line. If +she finds she cannot herself connect with Mrs. Jones’ “jack,” because +it is on another part of the board out of her reach, she makes a +connection with another operator who can reach Mrs. Jones’ line. The +second operator then makes the connection with Mrs. Jones’ “multiple +jack” and places her line in connection with Mrs. Smith’s line at the +first operator’s position. At the same time the first operator pushes +the operator’s key back, thus ringing Mrs. Jones’ bell. + +“Supervisory lamps” on the board before her, connected with the +“connecting cords,” tell the operator when Mrs. Jones answers the +summons. They flash when the connection is made and one goes out just +as soon as Mrs. Jones takes the receiver from the hook to answer. +If one of these lamps flashes and dies out alternately it tells the +operator that either Mrs. Smith or Mrs. Jones is trying to attract her +attention and she connects herself and ascertains the party’s wishes. +When both subscribers “hang up,” both lights flash to indicate the +end of the conversation. The operator then disconnects the cords from +the subscribers’ “jacks” and presses the “message register” button +recording the call against Mrs. Smith. + +[Illustration: ROUTINE OF A TELEPHONE CALL + +The subscriber, after looking up in the directory the desired number, +takes the telephone off the hook, which causes a tiny electric light to +glow in front of the operator assigned to answer his calls. (In some +exchanges equipped with a magneto system, a drop is released by the +turning of a crank.)] + +[Illustration: The arrow indicates the light as it appears on the +switchboard. Each operator can connect a caller with any subscriber +in that exchange, but she is assigned to answer the calls of only a +limited number of subscribers whose signals are these lights showing at +her particular position.] + +[Illustration: She takes up a brass-tipped cord, inserts the tip, +or “plug,” into the hole, or “jack,” just above the light, at the +same time throwing a key with the other hand in order to switch her +transmitter line into direct communication with the caller, and says: +“Number?”] + +[Illustration: The caller replies by giving the name of the exchange +and the number he wants, as for example, “Main 1268.” The operator +repeats the number, “One-two-six-eight,” pronouncing each digit with +clear articulation, to insure its correctness, and, if it be from a +subscriber in the Main Exchange, she--] + +[Illustration: Takes up the cord which is the team mate, or “pair,” of +the one with which she answered the caller, locates the jack numbered +1268, and “tests” the line by tapping the tip of the plug for a moment +on the sleeve of the “jack” to ascertain if the line is “busy.” If no +click sounds in her ear she--] + +[Illustration: Pushes in the plug and with her other hand operates a +key on the desk. The first action connects the line of the subscriber +called; the second rings his bell. When either party hangs up his +receiver, a light glows on the switchboard desk, showing the operator +that the conversation is ended.] + +[Illustration: THE CENTRAL TERMINAL OF YOUR TELEPHONE + +A MULTIPLE SWITCHBOARD] + +[Illustration: THE BACK OF A MULTIPLE SWITCHBOARD] + +[Illustration: THE BIRTHPLACE OF THE TELEPHONE, 109 COURT STREET, BOSTON + +On the top floor of this building, in 1875, Prof. Bell carried on his +experiments and first succeeded in transmitting speech by electricity] + + +How the Telephone Came to Be. + +It is hard to realize that there was once a time, not so very many +years ago, when the telephone was regarded as a scientific toy and +hardly anyone could be found willing to invest any money in the +development of the telephone business. + +[Illustration: ALEXANDER GRAHAM BELL IN 1876] + +[Illustration: THOMAS A. WATSON IN 1874] + +The story of Professor Alexander Graham Bell’s wonderful invention is +full of romantic interest and the early days of its exploitation were +replete with dramatic incidents. + +~THE MEN WHO MADE THE TELEPHONE~ + +Young Bell had come to America in 1870 in search of health, the family +settling at Brantford, Canada. He numbered among his forebears many +distinguished professional men. For three generations the Bells had +taught the laws of speech in the universities of Edinburgh, Dublin and +London. He himself was an accomplished elocutionist and an expert in +vocal physiology. + +During the year spent in Canada in regaining his health, Bell taught +his father’s method of visible speech to a tribe of Mohawk Indians and +began to think about the “harmonic telegraph.” + +In 1871 young Alexander Bell accepted an offer from the Boston Board +of Education to teach the “visible speech” method in a school for deaf +mutes in that city. + +For two years he devoted himself to the work with great success. He was +appointed a professor in the Boston University and opened a school of +“Vocal Physiology” which was at once successful. + +He might have continued his career as a teacher had it not been that +his active brain still clung to the “harmonic telegraph” idea and his +inventive genius demanded an outlet. + +[Illustration: PROF. BELL’S VIBRATING REED] + +So we find him in 1874 working out his idea of the “harmonic +telegraph,” the perfection of which meant a fortune to the young +inventor. That he never realized his goal was due to the fact that +while experimenting, he made a discovery which led to a far greater +invention and one that was fraught with more benefit to mankind than +the “harmonic telegraph” could ever have been. + +It was while working with his faithful man Friday, Thomas A. Watson, +in the dingy little workrooms on Court Street, Boston, that Bell got +the inspiration which made him turn from the “harmonic telegraph” to +devote himself to the invention which was destined to make his name +famous--the speaking telephone. + +~THE FIRST SOUND OVER A WIRE~ + +Mr. Watson has dramatically described the incident as follows: + +“On the afternoon of June 2, 1875, we were hard at work on the same +old job, testing some modification of the instruments. Things were +badly out of tune that afternoon in that hot garret, not only the +instruments, but, I fancy, my enthusiasm and my temper, though Bell +was as energetic as ever. I had charge of the transmitters, as usual, +setting them squealing one after the other, while Bell was retuning +the receiver springs one by one, pressing them against his ear as I +have described. One of the transmitter springs I was attending to +stopped vibrating and I plucked it to start it again. It didn’t start +and I kept on plucking it, when suddenly I heard a shout from Bell in +the next room, and then out he came with a rush, demanding, ‘What did +you do then? Don’t change anything. Let me see!’ I showed him. It was +very simple. The make-and-break points of the transmitter spring I was +trying to start had become welded together, so that when I snapped the +spring the circuit had remained unbroken while that strip of magnetized +steel by its vibration over the pole of its magnet, was generating that +marvelous conception of Bell’s--a current of electricity that varied in +intensity precisely as the air was varying in density within hearing +distance of that spring. That undulatory current had passed through +the connecting wire to the distant receiver which, fortunately, was +a mechanism that could transform that current back into an extremely +faint echo of the sound of the vibrating spring that had generated it, +but what was still more fortunate, the right man had that mechanism +at his ear during that fleeting moment, and instantly recognized +the transcendent importance of that faint sound thus electrically +transmitted. The shout I heard and his excited rush into my room were +the result of that recognition. The speaking telephone was born at +that moment. Bell knew perfectly well that the mechanism that could +transmit all the complex vibrations of one sound could do the same for +any sound, even that of speech. That experiment showed him that the +complex apparatus he had thought would be needed to accomplish that +long-dreamed result was not at all necessary, for here was an extremely +simple mechanism operating in a perfectly obvious way, that could do +it perfectly. All the experimenting that followed that discovery, up +to the time the telephone was put into practical use, was largely a +matter of working out the details. We spent a few hours verifying the +discovery, repeating it with all the differently tuned springs we had, +and before we parted that night Bell gave me directions for making the +first electric speaking telephone. I was to mount a small drumhead +of gold-beater’s skin over one of the receivers, join the center of +the drumhead to the free end of the receiving spring and arrange a +mouthpiece over the drumhead to talk into. His idea was to force the +steel spring to follow the vocal vibrations and generate a current of +electricity that would vary in intensity as the air varies in density +during the utterance of speech sounds. I followed these directions and +had the instrument ready for its trial the very next day. I rushed it, +for Bell’s excitement and enthusiasm over the discovery had aroused +mine again, which had been sadly dampened during those last few weeks +by the meagre results of the harmonic experiments. I made every part of +that first telephone myself, but I didn’t realize while I was working +on it what a tremendously important piece of work I was doing. + +[Illustration: WHAT THE FIRST TELEPHONE LOOKED LIKE + +ALEXANDER GRAHAM BELL’S FIRST TELEPHONE] + + +The First Telephone Line. + +“The two rooms in the attic were too near together for the test, as +our voices would be heard through the air, so I ran a wire especially +for the trial from one of the rooms in the attic down two flights to +the third floor where Williams’ main shop was, ending it near my work +bench at the back of the building. That was the first telephone line. +You can well imagine that both our hearts were beating above the normal +rate while we were getting ready for the trial of the new instrument +that evening. I got more satisfaction from the experiment than Mr. Bell +did, for shout my best I could not make him hear me, but I could hear +his voice and almost catch the words. I rushed upstairs and told him +what I had heard. It was enough to show him that he was on the right +track, and before he left that night he gave me directions for several +improvements in the telephones I was to have ready for the next trial.” + +Then followed many heart-breaking months of experimenting and it was +not until the following March that the telephone was able to transmit +a complete, intelligible sentence. + +[Illustration: TELEPHONE APPARATUS PATENTED IN 1876 BY PROF. BELL, +PHOTOGRAPHED FROM THE ORIGINAL INSTRUMENTS IN THE PATENT OFFICE AT +WASHINGTON] + +On February 14, 1876, Professor Bell filed at Washington his +application for patents covering the telephone which he described as +“an improvement in telegraphy” and on March 3, of the same year, the +patent was allowed. + +That was the year of the Centennial Exposition at Philadelphia and +Professor Bell had a working model of the telephone on exhibition. +Tucked away in an obscure corner it had attracted but little attention, +until on June 25th an incident occurred which had a tremendous effect +in giving to the new invention just the sort of publicity it needed. + +Professor Bell himself describes the incident in the following +interesting manner: + +“Mr. Hubbard and Mr. Saunders, who were financially interested in the +telephone, wanted this instrument to be exhibited at the Centennial +Exhibition. In those days--and I must say even up to the present time +I am afraid to say it is true--I was not very much alive to commercial +matters, not being a business man myself. I had a school for vocal +physiology in Boston. I was right in the midst of examinations. + +“I went down to Philadelphia, growling all the time at this +interruption to my professional work, and I appeared in Philadelphia +on Sunday, the 25th. I was an unknown man and looked around upon the +celebrities who were judges there, and trotted around after the judges +at the exhibition while they examined this exhibit and that exhibit. My +exhibit came last. Before they got to that it was announced that the +judges were too tired to make any further examinations that day and +that the exhibit could be examined another day. That meant that the +telephone would not be seen, for I was not going to come back another +day. I was going right back to Boston. + +~HOW AN EMPEROR SAVED THE TELEPHONE~ + +“And that was the way the matter stood--when suddenly there was one man +among the judges who happened to remember me by sight. That was no less +a person than His Majesty Dom Pedro, the Emperor of Brazil. I had shown +him what we had been doing in teaching speech to the deaf in Boston, +had taken him around to the City School for the Deaf and shown him the +means of teaching speech, and when he saw me there he remembered me +and came over and shook hands and said: ‘Mr. Bell, how are the deaf +mutes of Boston?’ I said they were very well and told him that the next +exhibit on the program was my exhibit. ‘Come along,’ he said, and he +took my arm and walked off with me--and, of course, where an Emperor +led the way the other judges followed. And the telephone exhibit was +saved. + +[Illustration: THE FIRST TELEPHONE SWITCHBOARD USED. EIGHT SUBSCRIBERS.] + + +An Emperor Wonders. + +“Well, I cannot tell very much about that exhibit, although it was +the pivotal point on which the whole telephone turned in those days. +If I had not had that exhibition there it is very doubtful what the +condition of the telephone would be today. But the Emperor of Brazil +was the first one to bring that situation about at that time. I went +off to my transmitting instrument in another part of the building, and +a little iron box receiver was placed at the ear of the Emperor. I told +him to hold it to his ear, and then I heard afterward what happened. I +was not present at that end of the line. I went to the other end and +was reciting, ‘To be or not to be, that is the question,’ and so on, +keeping up a continuous talk.” + +“I heard afterward from my friend, Mr. William Hubbard, that the +Emperor held it up in a very indifferent way to his ear, and then +suddenly started and said, ‘My God! it speaks!’ And he put it down; and +then Sir William Thomson took it up and one after another in the crowd +took it up and listened. I was in another part of the building shouting +away to the membrane telephone that was the transmitter. Suddenly I +heard a noise of people stamping along very heavily, approaching, and +there was Dom Pedro, rushing along at a very un-Emperor-like gait, +followed by Sir William Thomson and a number of others, to see what I +was doing at the other end. They were very much interested. But I had +to go back to Boston and couldn’t wait any longer. I went that very +night.” + +“Now, it so happened there, that, although the judges had heard speech +emitted by the steel disc armature of this receiving instrument, they +were not quite convinced that it was electrically produced. Some one +had whispered a suspicion that it was simply the case of the thread +telegraph, the lovers’ telegraph, as it was known in those days, and +that the sound had been mechanically transmitted along the line from +one instrument to the other. Of course, I did not know about it at that +time; but when the judges asked permission to remove the apparatus +from that location I said, ‘Certainly, do anything you like with it.’ +But I could not remain to look after it; they had to look after it +themselves.” + +“My friend, Mr. William Hubbard, who had kindly come up from Boston +to help me on this celebrated Sunday, June 25, said he would do his +best to help them out, although he was not an electrician. He knew +nothing whatever about the apparatus, beyond being in my laboratory +occasionally, knowing me well. But he undertook to remove this +apparatus and set up the line under the direction of the judges +themselves. So they had an opportunity finally of satisfying themselves +that speech had really been electrically reproduced.” + +“Sir William Thomson’s announcement was made to the world in England, +before the British Association, and the world believed--and from that +time dates the popular interest in the telephone.” + +In October, 1876, the first outdoor demonstration, in which +conversation was carried on over a private telegraph wire, borrowed for +the occasion, took place between Boston and Cambridge, a distance of +two miles. + +In April, 1877, the first telephone line was installed between Boston +and Somerville. + +A month later an enterprising Boston man put up a crude switchboard +in his office and connected up five banks, using the system for +telephoning in the day-time and as a protection against burglars at +night. This was the beginning of the exchange system, all previous +telephoning having been between two parties on the same circuit. + +~NINE MILLION TELEPHONES IN U. S.~ + +Soon after exchanges sprang up in several cities, and by August of that +year there were 778 Bell telephones in use. From this modest beginning +the telephone has grown until on January 1, 1914, there were 13,500,000 +telephones in the world, nearly 9,000,000, or over 64 per cent being in +the United States. + +[Illustration: MODERN DISTRIBUTING FRAME + +When the wires come to this frame they are in numbered order in the +cable. The main frame redistributes these wires so that they are +arranged according to their call numbers, making it possible to connect +any wire with any other wire anywhere that telephone service is +installed.] + +[Illustration: HOW THE WIRES ARE PUT UNDERGROUND + +Breaking Up the Asphalt Pavement. First Step in Laying an Underground +Cable.] + +[Illustration: Laying Multiple Duct Tile Subway Through Which the +Cables Will Run.] + +[Illustration: Feeding Cable Into Duct as It is Being Pulled Through +Subway from the Other End.] + +[Illustration: A CABLE TROUBLE] + +The use of the telephone instrument is common, but it affords no idea +of the magnitude of the mechanical equipment by which it is made +effective. + +~UNSEEN FORCES BEHIND YOUR TELEPHONE~ + +To give you some conception of the great number of persons and the +enormous quantity of materials required to maintain an always-efficient +service, various comparisons are here presented. + +[Illustration: TELEPHONES. Enough to string around Lake Erie--8,000,000, +which, with equipment, cost at the factory $45,000,000.] + +[Illustration: WIRE. Enough to coil around the earth 621 +times--15,460,000 miles of it, worth about $100,000,000, including +260,000 tons of copper, worth $88,000,000.] + +[Illustration: LEAD AND TIN. Enough to load 6,600 coal cars--being +659,960,000 pounds, worth more than $37,000,000.] + +[Illustration: CONDUITS. Enough to go five times through the earth from +pole to pole--225,778,000 feet, worth in the warehouse $9,000,000.] + +[Illustration: POLES. Enough to build a stockade around +California--12,480,000 of them, worth in the lumber yard about +$40,000,000.] + +[Illustration: SWITCHBOARDS. In a line would extend thirty-six +miles--55,000 of them, which cost, unassembled, $90,000,000.] + +[Illustration: BUILDINGS. Sufficient to house a city of 150,000--more +than a thousand buildings, which, unfurnished, and without land, cost +$44,000,000.] + +[Illustration: PEOPLE. Equal in numbers to the entire population of +Wyoming--150,000 employes, not including those of connecting companies.] + +The poles are set all over this country, and strung with wires and +cables; the conduits are buried under the great cities; the telephones +are installed in separate homes and offices; the switchboards housed, +connected and supplemented with other machinery, and the whole system +kept in running order so that each subscriber may talk at any time, +anywhere. + + + + +Where Does Sound Come From? + + +Somebody or something causes every sound we hear. Sounds are the result +of disturbances in the air. Sound is produced by waves in the air. The +buzz of the bumble-bee is caused by the quick movement of his wings +in the air. The wings themselves do not make the sound, but their +motion causes waves or vibrations in the air which produce the sound +of buzzing. Every motion made by anybody or anything produces waves in +the air just like the waves you see in the water--a big movement makes +a big wave and a tiny movement a tiny wave. When you clap your hands +you make a disturbance in the air which causes a sound--the harder you +clap the louder the sound. You can hear this sound and anybody else +near can hear it. If there were no air about us, however, we would hear +no sound, even if we could live in such a condition of things, for it +is the air waves produced striking against the drum of our ears that +enable us to discern sounds. When we talk we make air waves also and +thus produce sound. If you were deaf, and talked, you could not hear +any sound, because even when there are air waves they must still strike +against a sounding board in order to be recognized as sound--and the +drum of our ear is our sounding board for hearing sounds. + +When the air waves produced are regular we call the sound musical, and +when they are irregular we call it noise. Some people can make musical +sounds when they sing, while others cannot. + +If you take a piece of thin wire and stretch it tightly, fastening it +at both ends, and then pull it with your finger and let go, you will +hear a musical sound, because the vibrations produced will be regular +and will continue for some time. If you shorten the distance on the +wire where it is fastened at both ends and pull it as before, the +sound produced will be in a higher key. If you take a guitar and snap +the big G string you will produce the bass note of G. If the other +G string (the smaller one) is in tune (if you watch the smaller one +closely while you strike the larger one) you will notice the smaller +one vibrate also. Sound waves of the same tone, although in different +octaves, produce the same sounds, although in different keys. + +This is the principle on which the piano is made to produce music. +Inside the piano are wires of different lengths and the keys of the +piano are arranged to operate certain little hammers, each of which +strikes a certain wire. Every time you strike a piano key you cause one +of the little hammers to hit its wire--the wire then makes vibrations +which cause air waves. The air waves strike against the sounding board +which is located behind the wires, and being thrown back into the air, +strike against the drum of our ears, and we can hear the note. + + + + +Why Can We Make Sounds With Our Throats? + + +The sounds we make when we talk are produced in exactly the same way +with the exception of the little hammers. In our throats are two cords +which we call our vocal cords. When we talk we cause these cords to +vibrate and thus we make the sounds of our voices. The most wonderful +part of this voice of ours is that with only two vocal cords or wires, +we can produce practically all the notes that can be made with a piano, +which has a wire or cord for every note, excepting that we cannot make +so many at one time. The human throat is so wonderfully constructed +that we can lengthen or shorten our vocal cords at will and produce, +with two strings, in our throats as many notes as it takes the piano +many more strings to produce. + + + + +Why Does the Sound Stop When We Touch a Gong that Has Been Sounded? + + +When we touch the gong we stop the sound waves which the gong gives +off when it is struck. These sound waves continue after the gong has +been struck in continuous vibrations until something stops them. When +you touch the vibrating gong, you stop its vibrating. If you only +touch your finger to the vibrating gong you can feel the vibrations +which cause a little tickling sensation. Naturally when you stop these +vibrations you stop the air waves which the vibrations cause, and thus +also the sound of these air waves striking your ear are stopped and the +sound ceases. + + + + +How Can Sound Come Through a Thick Wall? + + +A sound will come through a thick or thin wall only if the wall is a +good conductor of sound. Some things are good conductors of sound and +others are not, just as some things are good conductors of electricity +and others are not. If a wall is built of materials all of which are +good conductors of sound, the sound will come through it no matter how +thick. Wood is an especially good conductor of sound. It is even better +than air. You can stand at one end of a long log and have another +person at the other end hold up his watch in the air, and you cannot +hear the watch tick, but if the watch is “going” as we say, and you ask +the person holding it to put the watch against his end of the log, and +you then put your ear to the other end, you can hear the watch ticking +almost as well as if you had it to your own ear. In like manner you can +hear the scratching of a pin at the other end of the log. When you put +your ear against a telegraph pole you can hear the hum of the wires +while you cannot hear it through the air. All sound is produced by +sound waves and many solids are better conductors of sound waves than +the air. + +Sound waves, however, will sometimes not be heard as plainly through a +wall, because of the fact that the wall may be made of materials which +are not equally good conductors of sound. When a sound wave strikes a +poor conductor it loses some of its power and the sound, although it +may be heard through the wall, will be fainter. + + + + +What Is Meant by Deadening a Floor or a Wall? + + +By deadening a floor, for instance, we mean inserting between the +ceiling of the room below and the floor above, or in the instance of a +deadened wall, between the two sides of the wall, some substance like +felt, paper or other non-conductor of sound, which will prevent the +sound waves from passing through. This deadens them to the passing of +sound or makes them sound-proof. + + + + +What Makes the Sounds Like Waves in a Sea Shell? + + +The sounds we hear when we hold a sea shell to the ear are not really +the sound of the sea waves. We have come to imagine that they are +because they sound like the waves of the sea, and knowledge that the +shell originally came from the sea helps us to this conclusion very +easily. + + + + +What Are the Sounds We Hear in a Shell? + + +The sounds we hear in the sea shell are really air waves or sounds made +by air waves, because all sounds are produced by air waves. + +The reason you can hear these sounds in a sea shell is because the +shell is so constructed that it forms a natural sounding box. The +wooden part of a guitar, zither or violin is a sounding box. They have +the faculty of picking up sounds and making them stronger. We call them +“resonators,” because they make sounds resound. The construction of a +sea shell makes an almost perfect resonator. A perfect resonator will +pick up sounds which the human ear cannot hear at all and magnify them +so that if you hold a resonator to the ear you can hear sounds you +could not otherwise hear. Ear trumpets for the deaf are built upon this +principle. + +Sometimes when you, with your ear alone, think something is absolutely +quiet, you can pick up a sea shell and hear sounds in it. But the sea +shell will magnify any sound that reaches it. + +It would be possible, of course, to take a sea shell to a place where +it would be absolutely quiet and then there would be no sounds. + +There are such places, but very few of them. A room can be built which +is absolutely sound proof. + +[Illustration: SIBERIAN LAMBS IN SOUTH DAKOTA] + + + + +The Story in a Suit of Clothes + + +Where Does Wool Come From? + +We could not write the story of a suit of clothes without dealing +largely with the sheep, for it is only from the wool of the sheep +that the best, warmest and most lasting garment can be made. In order +that we may properly understand the development of the great wool and +clothing industry in America we must supply a brief history of our +sheep industry, for the sheep must always come before the clothing. + + +Who Brought the First Sheep to America? + +The sheep is not a native of America, but it came here with the first +white men. History records that Columbus on his way to this country +stopped at the Canary Islands to take on stores. Among other things +he loaded a number of sheep, some of which were later landed on the +new continent. What became of this early importation history does not +record, but it is probable that most, if not all, of them perished from +the attack of wild animals or at the hands of the natives. However, +when settlers began pouring into the new world many of them brought +along their sheep, so that from the earliest colonial days the sheep +constituted our most numerous domestic animals. This, indeed, was +necessary, for if the colonist was to survive the rigor of our climate +he must have an abundant supply of woolen clothing. In those days +clothing materials were limited to wool, flax and the skins of animals, +and, as may be supposed, wools were in very great demand. England and +most European countries prohibited the exportation of wool, in order to +increase the demand for the clothing which she manufactured. However, +as our new colonist had ample time and but little money, he desired +to make his own clothing rather than send such funds as he had to the +mother country. Therefore, the new settler, as a matter of necessity, +was forced to increase the domestic supply of wools. + + +Who Started to Make Clothing from Wool in America? + +Early records reveal that shortly after the year 1600 many of the +colonies passed laws for the purpose of encouraging the sheep industry. +In fact, some of them went so far as to prohibit the transportation +of sheep or wool from one colony to another. However, our new sheep +industry prospered, and well it should, for it had the backing of every +prominent patriot of the early days. Washington, Jefferson, Madison, +and Franklin all were enthusiastic advocates of sheep husbandry, for +they knew that unless a people had a large domestic supply of wool they +could not long remain independent or hope to gain independence from +foreign countries. In fact, at one time Washington owned as many as one +thousand sheep, and if he lived in the present day he would be regarded +as a sheep baron. Wool, next to food, is the most vital necessity of a +people, for when wars come wool becomes a contraband, and all foreign +supplies are shut off. Thus, in stimulating a domestic wool supply the +great wisdom of our early patriots was vindicated with the coming of +the Revolutionary War. When that great struggle came our foreign wool +supply was shut off, but on account of the foresight of these patriots +in encouraging home production, our colonists had a supply ample for +most of their needs. + +We not only had the wool, but the housewife had learned the art of +manufacturing wool into clothing by means of the spinning wheel, so +that when our soldiers went forth in that great struggle, which was to +bring to us independence, they were clad in garments made of American +grown wool and manufactured by the good housewife during her hours of +leisure. + +When affairs became tranquil, following the close of the Revolution, +settlement, which had largely been confined to the Atlantic coast, +pushed westward farther and farther into the wilderness. Each of +these settlers took with him his supply of sheep, for the purpose of +furnishing wool for clothing and meat for food. In the early days +wool was not grown for the purpose of sale, but to be used entirely +by the family of the producer. However, when settlement reached the +Mississippi River, conditions changed. Wool manufacturing had then been +established in the land, and it became customary to raise wool to sell +to these manufacturers, who had located along the Atlantic seaboard. + + +Why Does the Sheep Precede the Plow in Civilizing a Country? + +In all countries the sheep has been the pioneer of civilization. They +have settled and developed practically all new lands. In fact, so +firmly established has been this rule that it seems almost necessary +that the sheep should precede the plow, and thus prepare land for +agriculture. The reason for this is that the sheep is a tractable +animal and depends on man to guide its every step. It can endure +hardships that would destroy other forms of animal life. However, the +maintenance of a sheep industry requires an abundance of labor, and in +this way settlement always follows the sheep. So has it been in foreign +countries, and so was it in this country. + + +Where Does Most of Our Wool Come From? + +Sheep came into our western states early in the seventies, at a time +when these states were thinly settled, but following the sheep came the +labor incident to its care, and thus the railroads, stores, cities and +schoolhouses found their way into the land. Originally all of our sheep +industry was east of the Mississippi River. Then for a time it was east +of the Missouri River. To-day west of the Missouri River we have about +23,000,000 aged sheep, or more than one-half of the total in the United +States. In the pioneer days the western sheep skirmished on the range +for most of the food that it obtained. To-day conditions are different, +and, while the sheep is on the range for a short time each year, it +spends its summer in the National Forest, for which grazing a fee is +paid to the Federal Government. Its winters are spent largely around +the hay-stack of the farmer, and about fifty to sixty cents’ worth of +hay is fed to each sheep in the West each winter. With the coming of +spring the western sheep are divided into bands of about 1500, and each +two bands are placed in care of three caretakers, who care for and +protect the sheep either on the deeded land of the owner or on the land +rented from the Federal Government. + +[Illustration: SHEEP COMING OUT OF FOREST] + + +How Much Wool Does America Produce Yearly? + +So much for the history of our sheep. A few words now about wool. The +total wool crop of the United States is approximately 300,000,000 +pounds per year. The value of this crop is around $60,000,000 annually. + + +How Do We Get the Wool Off the Sheep? + +With the coming of spring our sheep are driven to large central plants, +where they are shorn by the use of machines driven by electricity or +steam power. One man shears about one hundred and fifty sheep per day. +For this he receives eight cents per head. When the wool is taken off +the sheep it is gathered up and carefully tied with string made of +paper. The tied fleece is then dropped into an elevator, and is carried +up about ten feet, where it is dropped into a large sack about three +feet in diameter and seven feet long. In this sack there is always a +wool tramper, who keeps tramping the fleeces down, so that about forty +fleeces are finally put into each sack, making the weight of the sack +approximately three hundred pounds. As these sacks are filled they are +carefully stored in a dry shed, and, when shearing is completed, are +hauled to the railroad station and shipped to the great wool centers of +Boston or Philadelphia. While the bulk of the wool in the United States +is produced west of the Missouri River, that territory manufactures +very little wool. So the western sheepman, who is thus forced to grow +his wool in the western states, pays about two cents a pound freight on +it back to the eastern market, where it is sold and later manufactured +into cloth. A part of this same clothing is then shipped west, to be +sold to the very man, in some instances, who produced the wool out of +which it is made. + +American wool, taken as a whole, is the best wool grown in the world. +It is not as soft as some Australian wool, but all of it possesses +a greater strength than foreign wools, and it has long since been +determined that clothing made of American wool will give better service +than that made of foreign wool. Of the wool used in the United States +for the manufacturing of clothing we produce about 70 per cent and +import about 30 per cent. + + +How Much Does the Wool In a Suit of Clothes Cost? + +It is customary for the person who buys clothing made of wool to +believe that the value of the wool in the cloth is what makes the +clothing seem expensive. However, if we take a man’s suit made of +medium-weight cloth, such as is worn in November, we find that it +requires about nine pounds of average wool to make the suit. For this +wool the sheepman receives an average of seventeen cents per pound, so +that out of the entire suit the man who produces the material out of +which the suit is made receives a total of $1.53. A suit such as is +here described would be of all wool and free from shoddy or any wool +substitute. It would be a suit that would be sold by the storekeeper +at $25.00, and if you had it made by the tailor he would charge you +$35.00. Yet the wool-grower furnished all the material out of which +the suit was made, and received as his share but $1.53. Thus it will +be clear to the person who buys clothing and reads these lines that no +longer can the blame for the high cost of clothing be laid at the door +of the wool-grower. + +While the wool-using population of the world is increasing very +rapidly, the number of wool-producing sheep in the world is decreasing. +Ordinarily this would mean that a point would be reached where the +supply of wool would be totally inadequate to meet the needs of the +public. However, this unfortunate possibility is being averted by the +energy and thrift of the sheepmen in breeding sheep that produce more +and better wool than was the case in the past. The sheep which Columbus +brought to this country, and, in fact, all the sheep of the world in +that day, produced wool of very coarse, inferior quality, and but very +little of it. One hundred years ago our sheep did not average three +pounds of wool per head, but by careful breeding and better feeding we +have brought the average fleece up to slightly more than seven pounds. +Of course, some sheep produce decidedly more wool than this, but the +fact that in one hundred years we have more than doubled the amount of +wool that a sheep produces and increased its quality very materially +speaks well for the ingenuity and determination of our sheep producers. +Probably as time goes on the average fleece may be still further +increased, so that in the next twenty-five years it is not too much to +hope that our sheep will produce on an average of one pound more wool +than they now do. + +Of course, as wool comes from the sheep, it naturally contains much +dirt. The sheep have run on the range or in the open pasture during +much of the year, and dust and dirt has settled into the wool. Then, +besides producing wool, the sheep excrete into the wool a fatty +substance known as wool fat. When the fleece is taken from the sheep +and sent to the market the first thing that the manufacturer does with +the fleece is to wash out all this foreign matter. The foreign matter +is of a considerable quantity, for 60 per cent of wool as it comes from +the sheep is dirt and grease, so that only 40 per cent of the sheep’s +fleece represents wool fibres. + +This wool fibre is a very delicate affair, being made up of thousands +of little cells, one laid on top of the other. On the surface of the +fibre are a lot of scales arranged something like the scales on a fish. +In the process of manufacturing the scales on one fibre lock with +scales on another fibre, and in that way the fibres are held together +in the piece of cloth. + +When wool is received at the factory it is in fleeces, and each fleece +contains different kinds of fibres--long and short--coarse and fine, +and it is necessary that these should be sorted into different kinds +or grades, as may be desired--perhaps six or eight different kinds, +according to the particular uses to which the different qualities are +to be put. + +[Illustration: + + Copyright American Woolen Company + +WOOL SORTING] + +The fleece is spread out on a table, the center of which is covered +with wire netting, and through this netting part of the dust and other +matter from the wool falls while the sorting is going on. Sorters tear +with the hands the different parts of the fleece from each other and +separate them into piles, according to their different qualities. + +All unwashed wool contains a fatty or greasy matter called yolk, which +is a secretion from the skin of the sheep. The effect of this yolk is +to prevent the fibres of the wool from matting, except at the ends, +where, of course, it collects dust, and, forming a sort of a coating, +really serves as a protection to the rest of the fleece while on the +sheep’s back. + +After the wool is sorted it is next cleansed or scoured, in order to +remove all this yolk, dirt and foreign matter, and this is accomplished +by passing the wool, by means of automatic rakes, through a washing +machine, consisting of a set of three or four vats or bowls, which +contain a cleansing solution of warm, soapy water, until all the grease +and dirt have been removed. + +Each bowl has its set of rollers, which squeezes out the water from +the wool before it passes into the next bowl. Having passed through +the last bowl and set of rollers the wool is carried on an apron made +of slats on chains, to the drying chamber, called the dryer, where is +taken out most of the moisture. + +The wool is now blown through pipes or carried on trucks to the carding +room. + +~DIFFERENCE IN WOOLENS AND WORSTEDS~ + +From this point the wool follows one of two different processes of +manufacture--that of making into worsteds or that of making into +woolens. + +Speaking in a general way, worsted fabrics are made of yarns in which +the fibres all lie parallel, and woolens are made of yarns in which +the fibres cross or are mixed. Ordinarily, worsteds are made from long +staple wools, and woolens from short staple wools. + +[Illustration: + + Copyright American Woolen Company + +WOOL SCOURING] + +By means of the comb the fibre is still further straightened out, the +short stock and noil, or nibs, are removed, and when the sliver comes +from the combs most of the fibres are parallel to each other. A number +of the slivers taken from the comb are then put through two further +operations of gilling, and wound into a large ball, which is called a +finished top. + +The next process in the manufacture of worsteds is carding. In this +process the wool is passed between cylinders and rollers, from +which project the ends of many small wires. These cylinders revolve +in opposite directions. The result is the opening, separating and +straightening of the fibres; and the wool is delivered in soft strands, +which are taken off by the doffer comb and wound upon a wooden roll +into the shape of a large ball, known as a card-ball or card-sliver, or +put into a revolving can. The sliver from a number of these balls or +cans is now taken and put through what is known as the gilling machine, +which to a degree straightens the fibres. + +From the gilling machine the wool comes off in soft strands. Four +strands are then taken to the balling machine, where is made a large +ball, ready for the combing. It takes eighteen of these balls to make a +set or fill up the comb. + +The dyeing is done in three ways--in the top, in the thread or skein +after being spun, or in the piece after it is woven. If the wool is to +be stock dyed--that is, dyed in the top--it is sent to the dyehouse to +be dyed the shade required, and afterwards returned to be gilled and +recombed ready for the drawing. + +[Illustration: + + Copyright American Woolen Company + +WORSTED CARDING] + +Up to this point there has been no twist given to the wool, nor any +appearance of a thread. The top, the soft untwisted end, is now run +through the drawing machine, the process sometimes consisting of nine +distinct operations, and is drawn and redrawn until reduced to the size +required for its special purpose; and the stock is then delivered to +the spinning room on spools, and is called roving. + +[Illustration: + + Copyright American Woolen Company + +GILLING AFTER CARDING] + +[Illustration: + + Copyright American Woolen Company + +COMBING] + +In the spinning the process of drawing continues until the twisted +thread is reduced to the size required, which, either singly or twisted +together in two, three or four strands, is to be used for weaving. + +The yarn is then very carefully inspected, and all imperfections which +would show in the finished goods are removed, and, if it is to be dyed +in the skein, the yarn is taken to a reel, where the skeins are made +ready for the dyehouse. + +~HOW CLOTH IS MADE FROM WOOL~ + +The threads must now be prepared for the loom, in order that the actual +weaving may be done. The thread is used in two ways in weaving--as +warp, which is the thread which runs lengthwise of the cloth, and as +filling, or woof, which runs across the cloth from side to side. + +[Illustration: + + Copyright American Woolen Company + +GILLING AND MAKING TOP AFTER COMBING] + +The warp threads--the threads which run lengthwise of the cloth--are +sized and wound upon large reels, and from these transferred to a large +wooden roll called the warp beam, which holds all the warp threads, +usually several thousands. + +The filling threads are put on shuttle bobbins and placed in the +shuttles to be refilled by the operatives as required, and as the +weaving progresses. + +The warp beam is then taken to the drawing-in room, where these several +thousand threads are drawn through wire heddles in a frame called the +harness, then drawn through a wire reed. The completed warp beam is now +ready for the loom. + +The harnesses are placed in the loom, and by means of what is called +the “head-motion,” part of the threads are raised and part are lowered. +This allows the filling shuttles to pass above some threads and below +others, filling out the pattern required. + +The cloth, having been made in such length as is desired, is taken from +the loom, and, by what is known as burling and mending, any knots or +threads woven in wrongly are removed, and any imperfections which have +been discovered through a careful examination are corrected. + +The web or cloth is scoured or washed and the oil and any foreign +matter removed. + +Undressed fabrics would now be fulled. This consists of running cloth +through a fulling machine, where, moistened with a specially prepared +soap, it is subjected to a great pressure and pounding, which aids in +giving the required finish. + +There are different kinds of finishes which require different +treatments, and it would be impracticable for us to dwell in detail +upon this matter here. + +If dyed in the piece, the web or cloth is taken to the dyehouse and +dyed. It is thoroughly rinsed, all moisture is extracted from it, and +it is dried. + +After drying the cloth is run through a machine by which it is brushed +and sheared, the brushing lifting the long fibres, and the shearing +cutting them off at even length. The cloth is put through the press, +which irons it out, giving it the lustre or the finish that is desired. +It is examined again for further imperfections, and if such have +occurred they are corrected. + +Measuring, weighing, rolling and tagging follow, and the cloth is +packed and ready for the market. + +Woolens are made from short staple wools, known as clothing wools, and +in the finished woolens the fibres of the yarns cross or are mingled +together. In the case of woolens, after the scouring, it is frequently +necessary to remove burrs or other vegetable matter from the wool. To +accomplish this the wool is dipped in a bath of chloride of aluminum or +sulphuric acid solution, then the moisture is extracted and the wool +is put through a drier, where the temperature must be at least 212 +degrees. This heat carbonizes the foreign substance, but has little +effect on the animal fibres of the wool. + +[Illustration: FINISHING BOX + +ENGLISH DRAWING + + Copyright American Woolen Company + +GILLING + +ENGLISH DRAWING + + Copyright American Woolen Company] + +Next, an ingenious machine called the burr picker removes the burr. + +Sometimes there is to be a blend of the wool with other stocks, and in +that case the several different wools are mixed together. + +[Illustration: GILLING, FIRST OPERATION + +ENGLISH DRAWING + + Copyright American Woolen Company + +REDUCER + +ENGLISH DRAWING + + Copyright American Woolen Company] + +~HOW WOOLEN CLOTH IS DYED~ + +Dyeing of woolens is done in three ways--in the wool, in the thread +after it is spun, or in the piece after it is woven. If the wool is +to be “dyed in the wool” it is now conveyed to the dyehouse, dyed the +shade required, then returned to the mixing room. + +During the process of scouring, when the yolk was removed, a large part +of the natural oil of the wool was also eliminated, and, in order to +restore this lubricant, the wool is sprinkled with an oil emulsion, and +the mixing picker thoroughly blends the wools. + +From here the wool goes to the cardroom, and by means of the carding +machine the fibres are carded and drawn and delivered to the finisher +in a broad, flat sheet. By means of the condenser it is divided into +narrow bands, and the wool--free as yet from twist--comes out in soft +strands. These strands or threads are called roping. + +[Illustration: MENDING ROOM + + Copyright American Woolen Company + +BURLING RAISING KNOTS + + Copyright American Woolen Company + +MENDING PERCHING + + Copyright American Woolen Company] + +[Illustration: DRAWING IN WARP THREADS + + Copyright American Woolen Co. + + Copyright American Woolen Co. + + Copyright American Woolen Co. + +WEAVING AND SCOURING] + +Now comes the mule spinning. The roping passes through rolls by which +it is drawn and twisted to the size required, and wound on paper cop +tubes or bobbins. Such of the yarn as is to be used for warp is then +spooled from the bobbins to dresser spools. It is sized and wound upon +large reels: from these transferred to the warp beam, as in the case of +worsteds. + +The processes of drawing-in, preparation for weaving, burling and +mending are practically the same as in the case of worsteds. + +~HOW THE CLOTH IS MADE PERFECT~ + +The finishing processes of woolens, like the finishing processes of +worsteds, vary with different fabrics, some fabrics being scoured and +cleansed in the washers before fulling, others going to the fulling +mill without cleansing. After fulling, the cloth is again washed +and rinsed, and if necessary to remove any vegetable fibres it is +carbonized. + +Napping or gigging raises the fibres to the nap desired. Gigging is +done by means of a wire napping machine or teasel gig, which raises +the ends of the fibres on the face of the cloth. The teasel is a +vegetable product about the shape of a pine cone, and it is interesting +to note that no mechanical contrivance has ever been invented to equal +it for the purpose. + +[Illustration: SPINNING THE WOOL + + Copyright American Woolen Company + +ENGLISH CAP SPINNING] + +The napping which has been raised by the teasel is sheared or cut to a +proper length by machine. The cloth is pressed, and, if it is desired +to finish it with lustre, it is wound upon copper cylinders and steam +is forced through it at a high pressure. + +[Illustration: + + Copyright American Woolen Company + +RING TWISTING] + +[Illustration: + + Copyright American Woolen Company + +BEAMING--YARN INSPECTING] + +[Illustration: + + Copyright American Woolen Company + +WOOLEN MULE SPINNING] + +[Illustration: + + Copyright American Woolen Company + +FINISHER WOOLEN CARDING] + +Next the cloth is dyed, if it is to be piece-dyed--that is, dyed in +the piece. If the cloth is a mixture, the wool was dyed immediately +after the scouring. In worsteds the dyeing is done either just after it +has been subjected to the first combing processes, or the yarn is dyed +in the skein or hank. + +[Illustration: + + Copyright American Woolen Co. + +PIECE DYEING + + Copyright American Woolen Co. + +FULLING CLOTH + + Copyright American Woolen Company + +FINISH PERCHING] + +[Illustration: + + Copyright American Woolen Company + +FINISHED CLOTH, READY FOR THE TAILOR] + +In the dry finishing the cloth is finished with various kinds of +finishes desired, and it is steamed, brushed, sheared and pressed. +Another examination for any imperfections or defects follows; the cloth +is measured, packed and tagged and is ready for the market. + +The difference between worsteds and woolens is principally that in the +threads or yarns from which worsteds are made the fibres of the wool +lie parallel, one to another, being made from combed wool, from which +the short fibres have been removed; and woolens are made from yarns in +which the fibres cross and are matted and intermixed. When finished +the effect of worsteds and woolens is materially different. Upon +examination it will be found that the worsted thread resembles a wire +in evenness, while the woolen thread is uneven and irregular. + +A worsted fabric when finished has a clear, bright, well defined +pattern, seems close and firmly woven, and is of a pronounced dressy +effect; while woolen cloths are softer, they are more elastic, the +colors are more blended, the threads are not so easily distinguishable +and the general effect is duller. + + + + +Why Can’t We See in the Dark? + + +We cannot see in the dark because there is no light to see by. To +understand this we must first understand that when we see a thing, as +we generally say, we do not actually see the thing itself, but only the +light coming from it. But we have become so used to saying that we see +the thing itself that for all practical purposes we can accept that as +true, although it is not scientifically exact. Scientifically speaking, +we see that part of the sunlight or other light which is shining upon +it, which the object is able to reflect. + +If there were no air about us we could not hear any sounds, no matter +how much disturbance people or things created, because it requires air +to cause the sound waves which produce sound, and air also to carry +the sound waves to our ears. In the same way, if there is no light +to produce light rays from any given object to our eyes, we can see +nothing. It requires light waves to produce the reflections of objects +to our eyes. Without light our eyes and their delicate organs are +useless. You cannot see yourself in a mirror when the quicksilver which +was once on the back of the glass has been removed, because there is +then nothing to reflect the light. We can only see things when there is +light enough about to reflect things to our eyes. When it is dark there +is no light, and that is the reason we cannot see anything in the dark. + + + + +Why Can Cats and Some Other Animals See in the Dark? + + +They cannot see in the real dark any more than human beings. These +animals can find their way in the dark and can see more than a human +being, because of one distinct difference in their eyes, which may for +them be considered an advantage. The pupils of their eyes can be made +much larger, and they can, therefore, let more light into their eyes +than people. The result is that when it is so dark that you cannot +see a thing and you decide it is really dark, the cat can still see, +because there is always a little more light left and she can open the +pupils of her eyes and make them larger, thus letting in more light, +and the little bit of light there is still left gets into her eyes and +she is able to see. But in a really dark room a cat could see no more +than you can. You see, our eyes open and shut more or less just like +those of the cat, according to the intensity of the light. When you go +out of the dark and shaded room into the bright sunlight and look at +the sun, you naturally squint your eyes without deliberately intending +to do so. This is nature’s way of preventing too much light getting +into your eyes at one time. Gradually the pupils of your eyes contract +and get smaller, until you can see, without squinting, anything in +the sunlight. If, then, you were to go right back into a dark or +shaded room, you would have to wait a moment or two before you could +see things distinctly in the room--until the pupils of your eyes had +dilated (become larger), so as to let in enough light to enable you to +see normally. The eye automatically enlarges and contracts the pupil of +the eye, to enable us to see distinctly in either light or less light +places. + + + + +Why Is It Difficult to Walk Straight with My Eyes Closed? + + +The reason we cannot do this always is because when we walk naturally +the steps taken by our right and left feet are not of equal length. +This difference in the length of the steps is due to the fact that our +legs are never exactly the same length. We think of them generally as +of the same length, but they are not, and this will be proven if you +measure them accurately. Now, then, the longer of the legs will always +take a longer step than the shorter one, and so, if our eyes are shut, +we walk in circles, unless we have something to guide us. When we +walk with our eyes open, we are able to overcome the tendency to walk +in circles, because our eyes help the brain to direct the legs on a +straight course. Another reason which affects the matter is that our +eyes are very necessary in keeping our bodies balanced on our feet, and +it is very difficult to learn to keep the body balanced with the eyes +closed. Now, when your eyes are closed and you attempt to walk in a +straight line your body balances from one side to the other, and this +fact, coupled with the first reason given, makes your course irregular. +But, say you, the man on the tight-rope has his eyes bandaged and he +walks a very straight line. Yes; but remember that he has a straight +tight-rope to guide him, and all he needs is to maintain his balance. +One can learn to walk in a straight line with the eyes closed, but it +takes a good deal of practice, as you will learn if you try. + + + + +Why Can’t We Sleep with Our Eyes Open? + + +We cannot sleep with our eyes open, because to be asleep involves +losing control of most of the functions of the body. When we sleep +the brain sleeps also. Perhaps it would be stated more clearly to say +that we cannot sleep while the part of the brain which controls our +activities is awake. There is a part of the brain which has the power +to open our eyes, i. e., lift the eyelids, and when that portion of the +brain ceases to exercise its power to keep the eyes open, they go shut. +Even when we are awake that part of our brain cannot keep our eyes +from winking, because there is another part of the brain which sees to +it that our eyes wink every so often. This is done for the purpose of +washing the eye-ball, and is the answer to another of your questions +which is given in another place in this book. When the engineer at the +electric light plant shuts off the power all the lights go out, and +when you go to sleep you automatically shut off the power that opens +your eyes, and the eyes are shut. The brain is asleep also, and if it +is not completely asleep, you are restless. + + + + +Why Do Our Eyes Sparkle When We Are Merry? + + +If you should watch very closely the eyes of a merry person when you +see them sparkle you would probably notice that the eyelids move up and +down more often under such conditions than ordinarily, and if you know +what moving the eyelids up and down in front of the pupil of the eye +does, you will have your answer. + +Every time the eyelid comes down it releases a little tear, which +spreads over the eyeball and washes it clean and bright. It does this +every time the eyelid comes down. Now, there is something about being +merry which has the effect of making the eyelids dance up and down, +and thus, every time the lid comes down, the ball of the eye is washed +clean and bright, and gives it the appearance of sparkling, as we say. + + + + +Why Do We Laugh When Glad? + + +We laugh when glad because the things which make us laugh combine +together to rouse those parts of the body which are involved in a +good laugh to act in a certain harmony, and when this combination is +arranged in a certain way it produces a laugh. Certain things in the +world, whether they are funny, ludicrous, or other things that produce +the laughing effect, cause the brain to work certain muscles and +nerves in a combination that produces a laugh. The impression which +reaches the brain causes these muscles and nerves to act involuntarily +and the laugh comes. It works just like the keys of the piano. Some +combinations of notes produce sad sounds and other combinations produce +glad sounds, but the combination when once touched will always produce +the same sound. It is the impressions made on the brain which start the +proper combination, and it does this instantly. Just as a pin prick in +the arm will at once send a “hurt” message to the brain and cause the +brain to jerk the arm away, so a laugh-producing combination of sounds, +or things we see, or feel, sends an impression to the brain which at +once sends out the “laugh” order. Some things make some people laugh +while they do not affect others at all. That is because our brains are +not always the same in regard to recording impressions. Some things +impress some brains one way and others entirely in a different way or +not at all. You do not laugh so heartily the second time you hear a +funny story, because the impression the brain receives when the story +is told the second time is not so vivid. + + + + +Why Do I Laugh When Tickled? + + +Practically the same things happen when we are tickled, and explains +why you laugh when tickled. When some one tickles the bottom of your +feet or your ribs or another part of your body it produces, in most +cases, the same effect on the brain as the laugh-producing sound or +sight, and arouses the same combination of muscles and nerves to +activity. It is just like pushing the button of an electric bell. When +you push the button the contact produces the spark which sets the +machinery of the bell in motion and the bell rings and will continue +to ring as long as you keep your finger on the button, or until the +spark-producing power of the battery is gone. Then, as in the case +of the bell, you cease to laugh, because the spark that produced the +laugh combination is gone. That is why some things tickle some people +very much and do not affect others. Some are not so sensitive to the +laugh-producing combination as others. After the thing that tickles you +has been going on for some time you are not tickled into laughter any +more, because the impression on the brain ceases to be as strong. + + + + +Why Don’t I Laugh When I Tickle Myself? + + +Your mind tells you there is no need to laugh when you tickle yourself. +Your mind will not respond to the tickling sensation when it is aware +that the cause of the tickle is yourself. The reflex action of the mind +which causes laughter and squirming when some one else tickles you only +acts when it is not conscious of the cause. + +The whole purpose of the sensitive organization of our skins is to +give us information and cause action which will enable us to protect +ourselves when any outside influence touches us. An injurious touch +causes shock and pain, and the harmless tickle arouses the laughing and +squirming sensation. + + + + +What Happens When We Laugh? + + +Laughter is what we call a reflex action. When something occurs to +make us laugh, whether it is something we see, or feel, or hear, it is +because certain sensory nerves receive an impression in one of three +ways, carry it to the nerve centre and the nerve centre then sends +the same impression along certain efferent nerves, which connect with +certain muscles or glands, and excite them to activity. The action is +practically the same as when you hold a light before a mirror. The +rays from the light strike the surface of the mirror and are reflected +back from the surface, lighting perhaps corners of the room, which the +direct rays from the light could not reach, all depending upon the +angle of reflection. Light will always reflect from a mirror that is +exposed to it. + +Now, then, when you see, hear or feel anything that makes you laugh, +the sensory nerves have only to receive the impression to bring on +the explosion of laughter. Something touched the laugh nerves or the +laugh trigger that caused it to go off. You can prove that it is a +matter of impression entirely by noting that some people can listen +to a perfectly funny story, even when told by a clever performer, and +never crack a smile, while others burst into uncontrollable laughter, +and he who does not even smile may be listening even more intently than +the other--he may even be looking for a laugh. It all depends upon the +impression that is made upon the nerves. The muscles have the power +to express the state of gladness which is indicated by laughter when +certain impressions pass along the nerves which operate them, just as +they can be made to do other things when the proper cause for action is +shown them. + + + + +Why Do We Cry When Hurt? + + +We cry when we are hurt for the same reason that we laugh when we +are glad. The muscles and nerves, under the direction of the brain, +produce the cry just as the muscles and nerves produce laughter, +although they are probably, but not necessarily, a different set of +muscles and nerves. + +When we are hurt in any part of our body or feelings the impression +does not affect us until it reaches the brain. Then instantly, of +course, the body and brain go to work to destroy the pain. The first +thing, of course, is to give a warning to other parts of the body that +there is a hurt, and our crying is a warning to other people that we +are hurt. That is probably the only good that crying does. It does not +remove the hurt--it only tells others of our troubles. We cry with the +lower part of the brain--the only portion of the brain which is active +in a little baby. This is why even a tiny baby can cry. Crying is the +only thing a baby can do to give warning of its distress or discomfort. +Later in life the upper part of the brain develops. This is the master +of the lower part. Therefore, we do not always cry when hurt as we grow +older, because the master brain sometimes tells the lower brain that to +cry will not help matters in the least, even though we are inclined to +cry. Sometimes the hurt or shock to older people is so great or sudden +that we cry out before the controlling part of the brain has had time +to get in its work of preventing the outcry, but we are able to stop +crying when the master brain again secures control. + + + + +Where Do Tears Come From? + + +Tears are not made only when we cry. They seem to come only when you +cry, because it is then that they spill over. A little part of you +is making tears all the time, and your eyes are constantly washing +themselves in them. You have often noticed how you wink every few +seconds? You have often tried to keep from winking--to see how long +you could keep from winking. Boys and girls often do that, and when +you keep from winking what seems a long time, you notice how your eyes +ache and feel very dry just before you have to let them wink, in spite +of how hard you try not to, and just when you think you are not going +to. I will tell you just what winking does for the eyes. All of the +time your eyes are open the front, or the part you see things with, is +exposed to the dust and dirt that fills the air at all times, although +we cannot always see the dust. The wind, too, is constantly making them +dry. But have you ever noticed that although you never wash the inside +of the front of the eye, or pupil, it is always clean? Well, it is +because your eye washes itself every time you wink. I will tell you how +this is done. Up above each eye, inside, of course, there is a little +gland called the tear-gland. This gland is busy all the time you are +awake making tears. As soon as the front of your eye becomes dry, or +if a particle of dust or anything else strikes it, the nerves you have +there tell the brain, and almost at once the eyelid comes down with a +tear inside of it, and so washes the front of your eye clean again. It +does its work perfectly and as often as necessary. There is always a +tear ready to be used in this way. + + + + +Where Do the Tears Go? + + +Let me show you. Look right down here at the inner corner of my eyelid, +where you will see a little hole. That is where the tears get out of +the eye, when they have washed your eyeball clean. Where do they go +then? Did you ever notice how soon after you cry you have to blow your +nose? The reason for that is that when the tears go through the little +hole they run down into the nose. This making of tears and winking +goes on all the time while you are awake, and after they wash your eye +off they go on out through this little hole. But when you cry you make +more tears come than you need, so many, in fact, that they cannot all +get away through this little hole, and as there is no place else for +them to go, and as there is no place to keep them inside the eye, they +simply spill themselves right over the edge of your lower eyelid and +run down your cheek. + + + + +Story in a Barrel of Cement + + +What Is Cement? + +The dictionary tells us that cement is “any adhesive substance which +makes two bodies cohere.” Thus any material performing this function +may be called cement, such, for example, as the cement used in mending +broken china. Glue also is a form of cement. This story has to do with +Portland cement, which is a structural or building material used in +countless ways. + + +Why Is Cement Called Portland Cement? + +After being wet with water it hardens into stone, and it was given the +name “Portland” because, when first manufactured in England, and mixed +with sand and stone, it resembled a celebrated building stone called +Portland, which was obtained from the Isle of Portland. Compared with +other American industries, the manufacture of Portland cement is of +recent origin. Formerly all Portland cement was brought from foreign +countries. After successful manufacture became established in this +country, however, the industry advanced with great rapidity. A few +years ago the entire United States did not use as much cement as is +now used in any one of our large cities. At the time these facts were +written (1914) the manufacturers were making more than 90 millions of +barrels a year. + + +What Is Cement Made Of? + +Portland cement is composed chiefly of lime, alumina and silica. It +is manufactured from rocks, marl, clay and shale containing these +ingredients. If any one of them is lacking in the raw material as it +is taken from the earth, it is supplied during process of manufacture. +The greatest cement district in America is in Pennsylvania, and is +known as the “Lehigh District.” A rock containing proper constituents +for making Portland cement was found there in vast quantities, and for +a number of years the Lehigh District was the center of the industry. +In time it was found that certain clays, marls and shale could also be +manufactured into Portland cement, and thus mills have been erected +in all sections of the United States. One of the largest companies +in the United States found that cement could be manufactured from a +combination of blast-furnace slag and limestone, and this is now made +by the company in large quantities, the product being a true Portland +cement. + + +What Is Concrete? + +Portland cement is the strongest and most lasting of all modern mortars +or binding materials. When mixed with sand and stone the resulting +mixture is called concrete. Being a plastic material when first mixed, +it cannot be used as we use brick or stone, but must be poured into +molds or forms, which hold it in place until it hardens into rock. It +may be cast in any form or shape, and thus it is useful for a vast +number of purposes. It will harden under water, and time and exposure +to the elements merely increase its strength. The most common form in +which it is used, one familiar to everybody, is in the construction +of sidewalks. It is used in all great engineering projects, such as +the building of dams, bridges, retaining walls, sewers, subways and +tunnels. Being fireproof, large quantities of it are used in buildings +and likewise on our farms, where it is extremely valuable as an +enduring and sanitary material. + + +What Is Cement Used For? + +It has been said that concrete is a plastic material, meaning that +it is soft and pliable in the sense that clay or putty are plastic. +For this reason it is cast in forms or molds. Sometimes it is used in +the form of plain concrete, and on other occasions it is reinforced, +meaning that iron rods, steel bars or woven wire mesh are imbedded +in the concrete. When we speak of a “reinforced” concrete building, +imagine a huge wire bird cage encrusted within and without with +concrete. Place a block, beam or column of concrete upon the ground and +it will bear a tremendous load, meaning that it has great strength in +compression. On the other hand, if we were to place a long beam upon +supports at either end, leaving the greater length of it suspended and +without support, it would carry but a small load compared with concrete +in compression. Therefore, in making concrete beams or girders in a +building, strong steel bars are embedded in the concrete to take up +what are termed the tensile strains. + +[Illustration: WHAT A CEMENT MILL LOOKS LIKE + +This is a picture of a cement mill. Millions of dollars are invested in +these great mills, which are now located in practically all sections of +the country. Material is brought from the quarry to the mills, where it +passes through various stages, such as grinding, burning and bagging. +Expert chemists are employed to see that the cement is made exactly +right. It is a very scientific matter to make a thoroughly good cement. +There must be no guess work. Some mills are very large, the plant +comprising a number of buildings, and some companies operate several +mills in different localities. A single company supplied all of the +cement used in the Panama Canal, which great project required more than +six million barrels.] + +[Illustration: This picture shows a quarry in the famous Lehigh cement +district. The giant steam shovel or excavator burrows into the hill +like some great animal, and when the bucket is full it is dumped into +the cars shown on the track, which convey the rock or the raw material +to the mill.] + +[Illustration: WHERE THE MATERIAL IS OBTAINED + +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.] + +[Illustration: This is a view of a powerful rock crusher, which is +operated by the electric motor shown at the right. The cement rock is +brought from the quarry and dumped into the machine, from which it +issues in broken fragments, as shown in the illustration, this being +the first or preliminary crushing process.] + +[Illustration: THE HUGE ROCK GRINDERS + +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.] + +[Illustration: The kiln is a very important feature of the cement +plant. The finely ground raw material must be calcined or burned before +it becomes Portland cement. These kilns range from 60 to 240 feet in +length. They are slightly inclined and revolve upon rollers. The finely +ground material enters the kiln at the upper end and travels throughout +its length as the kiln slowly revolves. Powdered coal dust is fed into +the kiln at the lower end, where it is ignited and generates intense +heat. When the finely ground raw material comes into contact with the +heat, which reaches 2800 degrees F., it is transformed into what is +known as clinker, which issues from the lower end of the kiln and is +passed on to other machinery, which grinds it into impalpable powder or +Portland cement.] + +[Illustration: HOW CONCRETE IS MIXED + +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.] + +[Illustration: In mixing cement, sand and stone together in order that +concrete may be obtained, it is customary to use, if the operation +is a large one, what are known as mechanical mixers. These are large +iron cylinders into which the three materials are put and water added. +The cylinder or iron drum revolves until the contents are thoroughly +mixed, when they issue from the mixer through a chute or spout. A mixer +of this type is shown on a succeeding page describing the making of a +concrete road. This picture shows mixing concrete by hand. The sand and +cement are first thoroughly mixed in the dry state and subsequently the +stone and water are added. Concrete should be thoroughly mixed in order +that every grain of sand may be entirely coated with cement, and then +these two combined make a rich mortar, which should surround entirely +every piece of stone.] + +[Illustration: HOW CONCRETE BUILDINGS ARE MADE + +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.] + +[Illustration: This is a view of an arch built of concrete during the +Jamestown Exposition. It is a striking illustration of how concrete +may be used for both ornamental and practical purposes. In no field +has concrete proved to be of more value and economy than in the +construction of bridges, whether large or small. Some of the largest +bridges in the world are built of concrete, and in many cases iron +bridges are incased in concrete to keep them from rusting.] + +[Illustration: CONCRETE HOUSES CANNOT BURN + +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.] + +[Illustration: Just as mammoth structures are created with poured +concrete, so we may produce the most delicate and ornamental patterns. +These are usually cast in plaster molds and often in molds of wood or +iron. Where undercut work is required, such as in the sun-dial shown, a +wood or metal mold could not be removed without injury to the concrete, +and so sculptors have invented the pliable glue mold, which can be +easily removed and which will spring back to its original shape if +necessary to use it a second time.] + +[Illustration: Concrete in dwelling construction means the elimination +of fire danger and also cost of painting and repairs. This picture +shows a solid concrete house, parts of which have been encrusted with +beautiful tiles. Concrete has been successfully used in all types of +dwellings, from the humble abode of the workingman to the palace of +the multimillionaire. An entire house may be made of concrete, even to +the roof and stairways, and where a dwelling is constructed of this +material throughout, it is proof against fire and decay.] + +[Illustration: HOW THE FARMER USES CONCRETE + +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.] + +[Illustration: This is a concrete silo. A silo made of concrete is +merely a huge stone jar in which green food for cattle is preserved. +The crop is gathered and placed in the silo, thus insuring abundance +of green and wholesome food throughout dry seasons and during the +winter. The contents of the silo is known as silage or ensilage, and is +merely corn fodder cut when green. Concrete silos are both storm- and +fire-proof.] + +[Illustration: It is usual to consider concrete in connection with +great engineering enterprises, but nevertheless many millions of +barrels are used each year by the farmers of the United States. This +picture shows a clean, sanitary and durable concrete stable. In +buildings of this character concrete is rapidly supplanting wood, which +soon goes to decay, to say nothing of accumulation of filth.] + +[Illustration: HOW CONCRETE ROADS ARE BUILT + +MECHANICAL CEMENT MIXER] + +[Illustration: A CONCRETE ROAD + +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: + + 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. + +[Illustration: JAPAN THE NATURAL HOME OF THE SILK WORM + +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.] + +[Illustration: FEMALE MOTHS DEPOSITING EGGS.[1] + +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.] + +[Illustration: PREPARING COCOONING BEDS.[1] + +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. + +[Illustration: HOW THE SILKWORMS ARE CARED FOR + +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.] + +[Illustration: REMOVING SILKWORMS FROM CARDS WHERE THEY WERE HATCHED. + +Every few days the young worms are changed to new and clean cards.] + +[Illustration: METHOD OF REELING RAW SILK. + +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.” + +[Illustration: FULL GROWN LARVA--SHOWING POSITION IN MOLTING.[2]] + +[Illustration: MALE MOTH.[2]] + +[Illustration: FEMALE MOTH.[2]] + +[Illustration: SIDE VIEW OF CHRYSALIS.[2]] + +[Illustration: BOTTOM VIEW OF CHRYSALIS.[2]] + + [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. + +[Illustration: HOW THE SILKWORMS ARE REARED.[2]] + +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. + +[Illustration: SILKWORM EATING.[2]] + +[Illustration: SILKWORM—ONE OF THE WORLD’S GREATEST WORKERS + +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. + +[Illustration: COCOON BEGUN--SILKWORM CAN STILL BE SEEN.] + +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. + +[Illustration: COMPLETED COCOON.] + +~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. + +[Illustration: MOTHS EMERGING FROM COCOONS.] + +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. + +[Illustration: COCOONS FROM WHICH THE MOTHS HAVE EMERGED.] + +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. + +[Illustration: HOW THE COCOON IS UNWOUND + +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.”] + +[Illustration: A FILATURE--REELING THE SILK FROM COCOONS BY POWER +MACHINERY.[2]] + +[Illustration: DRYING SKEINS OF SILK.] + +[Illustration: THE SILK IS WOUND ON SPOOLS + +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. + +[Illustration: DOUBLING FRAMES--THE SILK THREAD IS MADE UNIFORM.] + +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. + +[Illustration: SPINNING SILK.[2]] + +[Illustration: TWISTING SILK.[2]] + +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. + +[Illustration: SILK THREADS READY FOR THE WEAVER + +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? + + +The term is applied usually to a public vehicle, known in England as +a “two-wheeler,” or “Hansom” (from the name of the inventor), and +drawn by one horse. In a hansom cab, the passenger or hirer of the +vehicle sits immediately in rear of the dashboard, the driver sitting +on an elevated perch behind, the reins being passed over the top. The +term cab is sometimes also applied to a four-seated, closed or open +carriage, drawn by one or two horses, the driver sitting in front. The +term is also applied to the covered part of a locomotive, in which the +engineer and fireman have their stations. The word cab is derived from +the cabriolet, a light one-horse carriage, with two seats and a calash +top. In London, England, the cab or hansom was called the “gondola” of +the British metropolis by Disraeli. + + + + +Where Did the Name Calico Come From? + + +A fabric of cotton cloth, the name being derived from the city of +Calicut, in Madras, where it was first manufactured, and in 1631 +brought to England by the East India Company. Calico-printing, an +ancient Indian and Chinese art, has become a great industry in this +country and in Britain, as well as in Holland. + + + + +Who Made the First Postage Stamp? + + +The stick on postage stamps so generally used today was invented by +an Englishman James Chalmers in 1834. The English Government passed a +bill calling for uniform postage of One Penny in 1840 and furnished +envelopes bearing stamps printed on them. The people did not like them, +however, and the adhesive stamp invented by Chalmers was substituted. +The first stamps used in America were introduced in 1847. People have, +it seems, always preferred to lick their postage stamps. + + + + +How Many Languages Are There? + + +It is said that there are more than 3,400 languages, including +dialects, in the world. Most of them belong, of course, to savage +or uncivilized people. There are said to be more than 900 languages +used in Asia, almost 600 in Europe, 275 in Africa and more than 1,600 +languages and dialects which are American. + + + + +What Is the Deepest Mine In the World? + + +The mine that goes farther down than any other in the world is the rock +salt mine near Berlin, Germany which is 4,175 feet. It is not, however, +straight down but somewhat slanting. The Calumet Copper Mine near Lake +Superior is at a depth in some places of 3,900 feet. + +The deepest boring in the world is an artesian well at Potsdam, +Missouri, which is 5,500 feet deep or more than one mile straight down. + + + + +What Is Color? + + +~WHAT PRODUCES THE COLORS WE SEE?~ + +What is termed the color-sense is the power or ability to distinguish +kinds or varieties of light and their distinctive tints. We owe the +faculty of doing this to the structure of the eye and its elaborate +connecting nerve machinery. The eye in man is specially sensitive to +light, and the sensations we feel through it enables us to distinguish +the different colors. Over 1,000 monochromatic tints are said to +be distinguishable by the retina of the eye, though these numerous +tints are, in the main, merely blendings or combinations of the three +primary color-sensations, the sense of red, of green and of violet. +Each of these colors, it has been demonstrated, is produced by light +of a varying wave length, while white light is only light in which the +primary colors are combined in proper proportion. Colored light, on the +other hand, as Newton proved, may be produced from white light in one +of three ways: First, by refraction in a prism or lens, as observed in +the rainbow; second, by diffraction, as in the blue color of the sky, +or in the tints seen in mother-of-pearl; and third, by absorption, +as in the red color of a brick wall, or in the green of grass--the +white light which falls upon the wall being wholly absorbed, save by +the red, and all that falls upon the grass being absorbed except the +green. In art, color means that combination or modification of tints +which is specially suited to produce a particular or desired effect in +painting; in music, the term denotes a particular interpretation which +illustrates the physical analogy between sound and color. + + + + +Where Did the Term Dixie Originate? + + +The term was applied originally to New York City when slavery existed +there. According to a myth or legend, a person named Dixie owned a +tract of land on Manhattan Island and had a large number of slaves. As +Dixie’s slaves increased beyond the requirements of the plantation, +many were sent to distant parts. Naturally the deported negroes looked +upon their early home as a place of real and abiding happiness, as did +those from the “Ole Virginny” of later days. Hence “Dixie” became the +synonym for a locality where the negroes were happy and contented. In +the South, Dixie is taken to mean the Southern States. There the word +is supposed to have been derived from Mason and Dixon’s line, formerly +dividing the free states from the slave states. It is said to have +first come into use there when Texas joined the Union, and the negroes +sang of it as Dixie. It has been the theme of several popular songs, +notably that of Albert Pike, “Southrons, Hear Your Country Call”; that +of T. M. Cooley, “Away Down South where Grows the Cotton,” and that +of Dan Emmett, the refrain usually containing the word “Dixie” or the +words “Dixie’s Land.” During the Civil War, the tune of “Dixie” was to +the Southern people what “Yankee Doodle” had always been to the people +of the whole Union and what it continued, in war times, to be to the +Northern people, the comic national air. The tune is “catchy” to the +popular ear and it was played by the bands in the Union army during +the war as freely as by those on the other side. During the rejoicing +in Washington over the surrender of Lee at Appomattox, a band played +“Dixie” in front of the White House. President Lincoln began a short +speech, immediately afterward, with the remark, “That tune fairly +belongs to us now; we’ve captured it.” + + + + +How Big Is the Earth? + + +The third planet in order of distance from the sun, Mercury and Venus +being nearer to it. It is in shape a sphere slightly flattened at the +poles and bulged at the equator, hence it is called an oblate spheroid. +The equatorial diameter or axis measures 7,926 miles and 1.041 yds., +and the polar diameter is 7,899 miles and 1.023 yds. The earth revolves +upon its axis, completing its diurnal or daily revolution in a sidereal +day, which is 3 minutes and 55.9 seconds shorter than a mean solar day. +It revolves around the sun in one sidereal year, which is 365 days, 6 +hours, 9 minutes, and 9 seconds. Its orbit or path around the sun is an +ellipse, having the sun in one of the foci. The earth’s mean distance +from the sun is 93,000,000 miles. Its axis is inclined to the plane +of its orbit at an angle of 23° 27′ 12.68″. The circumference at the +equator measures 24,899 miles. The total surface is 196,900,278 sq. +miles, and the solid contents is 260,000,000,000 cubic miles. As we +descend into the earth the temperature rises at the rate of 1° Fahr. +for every 50 ft. At the depth of 10 or 12 miles the earth is red-hot, +and at a depth of 100 miles the temperature is such that at the surface +of the earth it would liquefy all solid matter in the earth. + + + + +What Causes Hail? + + +Hail is the name given to the small masses of ice which fall in +showers, and which are called hailstones. When a hailstone is examined +it is found usually to consist of a central nucleus of compact snow, +surrounded by successive layers of ice and snow. Hail falls chiefly in +Spring and Summer, and often accompanies a thunderstorm. Hailstones +are formed by the gradual rise and fall, through different degrees of +temperature (by the action of windstorms), and they then take on a +covering of ice or frozen snow, according as they are carried through a +region of rain or snow. + +With regard to rain, it may be said, in popular language, that under +the influence of solar heat, water is constantly rising into the air by +evaporation from the surface of the sea, lakes, rivers, and the moist +surface of the ground. Of the vapors thus formed the greater part is +returned to the earth as rain. The moisture, originally invisible, +first makes its appearance as cloud, mist or fog; and under certain +atmospheric conditions the condensation proceeds still further until +the moisture falls to the earth as rain. Simply and briefly, then, rain +is caused by the cooling of the air charged with moisture. + + + + +Why Does a Human Being Have To Learn to Swim? + + +It is strange, isn’t it, that almost every animal, excepting man and +possibly the monkey, knows how to swim naturally; others such as birds, +horses, dogs, cows, elephants, can swim as soon as they can move about +alone. + +The trouble with man in this connection is that his natural motion is +climbing. He has been a climber ever since he was developed from the +monkey, and when you throw him into the water before he has learned to +swim, he naturally starts to climb and as a climbing motion won’t do, +for swimming, the man will drown. + +This climbing motion is as much of an instinct in man and monkeys as +the instinct in dogs which causes him to turn round once or twice +before he lies down just as his forefathers used to do ages ago when, +as wild dogs, they first had to trample the grass before they could lie +down comfortably. + + + + +Why Do I Get Cold in a Warm Room? + + +I suppose you mean the instances when you get cold while in a warm room +even when you are perfectly well. This will happen often when all of +the moisture in the room outside of what is in your body, is evaporated +by the heat in the room. The remedy is, of course, to keep a pan of +water some place in the room as the air has become too dry. + +While heat is necessary to evaporate water, the process of evaporation +produces cold. The quicker the evaporation the sharper the cold feeling +produced. Now your body is continually evaporating the water from your +body which comes out in the form of perspiration through the pores of +the skin. This is one of nature’s ways of taking the impurities and +waste out of the body. You know, of course, don’t you, that more than +one-half the waste material which the body expels from the system comes +out through the pores of the skin rather than through the canals. + +When the air in the room becomes too dry, the evaporation on the +outside of the body proceeds faster and makes you cold. By keeping +water in some vessel in the room you keep the air of the room from +becoming too dry. + + + + +Why Do They Call Them Wisdom Teeth? + + +The wisdom teeth are the two last molar teeth to grow. They come one +on each side of the jaw and arrive somewhere between the ages of +twenty and twenty-five years. The name is given them because it is +supposed that when a person has developed physically and mentally to +the point where he has secured these last two teeth he has also arrived +at the age of discretion. It does not necessarily mean that one who +has cut his wisdom teeth is wise, but that having lived long enough +to grow these, which complete the full set of teeth, the person has +passed sufficient actual years that, if he has done what he should to +fit himself for life, he should have come by that time at the age of +discretion or wisdom. As a matter of fact these teeth grow at about the +same age in people whether they are wise or not. + + + + +What Makes Freckles Come? + + +Freckles are generally caused by the exposure of unprotected parts of +the body to the sun, but this will not cause freckles on all people. +Only people with certain kinds of sensitive skins freckle. What happens +when freckles are produced in this way is this: The sunlight shining on +the face, neck or arms of anyone who has a tendency to freckle, has a +peculiar action on certain cells of the skin which produces a yellowish +brown coloring pigment, which remains for a time. + +Then again the skins of some people are so peculiarly sensitive the +cells develop this kind of coloring matter in almost any kind of light +and such people are, so to speak, apt to be freckled for life. + +[Illustration: First successful power-driven aeroplane. The Langley +monoplane with steam engine, which flew over the Potomac River in 1896.] + + + + +The Flying Boat + + +When Did Man First Try to Fly? + +~HOW MAN LEARNED TO FLY~ + +Man’s desire to conquer the air is older than recorded history. When a +kite was flown for the first time the principle of aviation, or dynamic +flight, was uncovered. For centuries man has sought the mechanical +equivalents for the things that keep a kite flying steadily in the +air,--the power that lies in the cord that keeps a kite headed into the +wind; an equivalent for the wind’s own power; an equivalent for the +tail which controls the kite’s lateral and longitudinal balance. + +Each separate part of the modern flying machine, or aeroplane, was +worked out long ago, with the exception of the gas engine light enough +and reliable enough to be used for this work. The present generation +knows dynamic flight as a commonplace thing, not because we are so much +more clever than previous generations in designing flying machines, +but because of the development of the modern gasoline or internal +combustion engine. + + +Who Invented Flying? + +No one invented flying, nor did any one man invent all the separate +parts of the flying machine. They are the result of evolution,--of the +combined work and thought of hundreds of men, many of whose names are +unrecorded. To attempt to find the true beginning of the modern flying +machine would be as difficult as attempting to discover who planted +the seed of the tree from which one has gathered a rose. But the tree +from which all the flying machines, or aeroplanes, of today have sprung +undoubtedly is Dr. Samuel Pierpont Langley, third secretary of the +Smithsonian Institution. + + +Some of the Men Who Helped. + +Taking the most conspicuous names of scientists who worked out various +details of the aeroplane during the past century we find that a century +ago Sir George Cayley built a machine on lines very similar to those +accepted today, and he went so far as to foretell the necessity of +developing the internal combustion engine before dynamic flight could +be a success. Mr. F. H. Wenham, in 1866, also built a flying machine +along conventional lines and tried to fly it with a steam engine, which +of course, proved too heavy. + +[Illustration: One of Dr. Langley’s first models; a biplane with +flexible wing-tips and twin propellers. 1889.] + +~EARLY TYPES OF FLYING MACHINES~ + +M. A. Penaud, a Frenchman, in experimenting with models, seems to have +been the first to discover the necessity of vertical and horizontal +rudders in maintaining balance. Mr. Horatio Phillips, an Englishman, +discovered, and patented, the use of curved instead of flat surfaces +for the planes. Otto and Gustav Lilienthal are said to have been the +first to attempt to balance aeroplanes by flexing or bending the wings. +Various others, including Messrs. Richard Harte, Boulton, Mouillard, +worked out ideas for balancing machines by the use of auxiliary planes +which could be set at different angles with regard to the line of +flight, thus forcing the machines to different positions by the force +of the air rushing against them. + +Dr. Langley, trained in scientific investigation, conducted an +elaborate series of experiments covering many years and costing +thousands of dollars to test and prove the value of the claims of +the earlier investigators. Some things which he thought he was +the first to discover,--such as the effect of the vertical and +horizontal rudders,--he later found had already been proven by others. +Independently he covered the entire field of experiment and after +building hundreds of small models he succeeded, in 1896, in making a +machine weighing several pounds equipped with a very light steam engine +which flew safely as long as the fuel lasted. For his early experiments +Dr. Langley was afforded financial assistance by Mr. William Thaw of +Pittsburg. After the success of his small machines Dr. Langley was +asked to undertake the construction of a large, man-carrying machine, +and Congress voted him $50,000 to carry on the work. A large share of +this was spent on the development of a very light gasoline engine. The +machine finally was completed, but was twice broken through defective +launching apparatus. Congress and Dr. Langley were so ridiculed by the +public press that the machine was temporarily abandoned. Not, however, +until after Dr. Langley had successfully flown a steam driven machine +much larger than many of the racing aeroplanes of today. + +But eight years after Dr. Langley’s death, which is said to have been +due to the heart-breaking disappointment he suffered in trying to +demonstrate the large machine, Glenn H. Curtiss, at the request of the +Smithsonian Institution, rebuilt the old Langley machine and succeeded +in making a flight with it at Hammondsport, N. Y., on May 28, 1914. + +[Illustration: THE FIRST MAN-CARRYING AEROPLANE + +First successful man-carrying aeroplane. Designed by Dr. Langley in +1898; flown by Glenn H. Curtiss at Hammondsport, N. Y., 1914.] + +[Illustration: Front view of big Langley machine in 1914.] + +While longer flights probably will be made with this machine none +will attain greater importance, because this first flight with it was +sufficient to establish for all time the fact that Dr. Langley built +the first man-carrying machine equipped with a gasoline engine and able +to fly and raise itself with its own power. This was considerably +more than was accomplished by other machines for some time after Dr. +Langley’s death. The Langley machine not only lifted the weight it was +designed to fly with, but also carried pontoon and other fittings, +added by Mr. Curtiss to make flight from the water possible, which +added 340 pounds to the original weight of the machine. + +[Illustration: THE MACHINE WITH WHICH BLERIOT FLEW IN EUROPE + +Copy of early Langley model with which Bleriot made first circular +flight in Europe.] + +The connection between Dr. Langley’s work and present machines is now +very easy to trace, though not obvious until 1911, when the Smithsonian +Institution published memoirs written by Dr. Langley in 1897, and +some memoirs of Mr. Octave Chanute, a French engineer who resided in +Chicago, and who forms one of the main connecting links. The chain +is practically completed by notes left by the late Lieut. Thomas +Selfridge, U. S. A., America’s first martyr to aviation. + +Dr. Langley’s knowledge is represented in modern aviation by three +distinct lines. The central and most direct line is through Dr. +Alexander Graham Bell, inventor of the telephone, to the Aerial +Experiment Association, and thence to Mr. Glenn H. Curtiss, and finds +its expression in what is known as the Curtiss type of machines. + +Another line is that carried by a Mr. A. M. Herring to Mr. Chanute and +by him transmitted to Mr. Wilbur Wright, finding expression in the +Wright type of biplane. + +The third line is that leading to the modern monoplane school; M. +Bleriot having first copied in toto the tandem monoplane form, +generally known as the Langley type, and later, with the development of +better gasoline engines, developing into the monoplane as known today. + +With the exception of M. Bleriot it is doubtful if the others fully +realized the source of their inspiration,--not to call it information. + +Dr. Bell was interested in Dr. Langley’s work for more than ten years +before Dr. Langley gave up. He observed many of the trials, and his +reports of the first successful flights are incorporated in the +official publications of the Smithsonian Institution. Dr. Bell began +some independent experiments, but following Dr. Langley’s death he +formed the Aerial Experiment Association, to carry on the work left by +Dr. Langley. The members of this organization were, Mr. Curtiss, at +that time the most successful builder of light motors; Lieut. Thomas +H. Selfridge, U. S. A.; Mr. J. A. D. McCurdy and Mr. F. W. Baldwin, two +young Canadian engineers. Mrs. Bell financed the project, furnishing +the sum of $35,000 for the experiments. + +~WHAT TWO BROTHERS ACCOMPLISHED FOR FLYING~ + +The Wright Brothers, for Wilbur Wright was joined by his brother +Orville in the experiments, were the first to reap success from the +seeds of Dr. Langley’s sowing. Mr. Chanute had been experimenting +with a biplane form of motorless glider with little success, because +of lack of means for balancing the machines in the air, until he was +joined by a former employe of Dr. Langley. He appears to have imparted +to Mr. Chanute the secret of the stabilizing effect of the Penaud +tail, or combination of vertical and horizontal rudders. Thereafter +hundreds of successful gliding flights were made with the Chanute +biplane, though Chanute seems not to have grasped the full significance +of the rudders,--though it was well understood by Dr. Langley. To +the Chanute machine, as described to him, Mr. Wright added first the +idea of flexing or warping the wings, after the fashion set by the +Lilienthals. He found, however, as Dr. Langley had found years before, +that in attempting to correct lateral balance in this way caused the +aeroplane to swerve to such an extent that the fixed vertical rudder, +as originally employed, did not correct the upsetting tendency that was +developed. Mr. Wright then arranged his rudder in such a way that when +the wing was warped the rudder turned in a way to offset the swerve. +This combination was patented all over the world and has resulted in +much complicated litigation. + +To this machine the Wright Brothers added a gasoline motor in December, +1903, and with it made numerous flights during 1904-5. Their claims +were not generally credited however until a later date for their +experiments had been conducted with considerable secrecy, and during +1906, 1907 and until late in 1908 they did no more flying. + +In the meantime M. Bleriot had made a copy of one of the early Langley +tandem monoplane models and made some fairly successful flights with it +in Europe. Later, as gasoline motors developed in power for weight, he +reduced the rear surface until the modern monoplane evolved. + +While Bleriot was working in Europe, Dr. Bell’s Aerial Experiment +Association in America was evolving still another type of machine, and +the members of the association made the first successful public flights +in America. Mr. Curtiss won the Scientific American Trophy for the +first time on July 4th, 1908, by a straightaway flight of more than a +kilometer. The balancing system employed by the A. E. A. differed from +that employed by the Wrights and by Bleriot in that small auxiliary +planes took the place of warping planes for righting the machine. This +they claimed to be a superior method, first, because it eliminated the +use of the rudder as being absolutely essential to the balance of the +machine; second, because it enabled them to make the main planes rigid +throughout, and consequently stronger than the flexible planes. + +There are several other names that must be mentioned in connection +with the early history of successful flight; these are the Frenchmen, +Messrs. Henri Farman, Maurice Farman, the brothers Voisin, and Santos +Dumont. These produced some of the first notably successful aeroplanes +in Europe but seem to have discovered nothing which has had any marked +effect upon the later development of flying machines. M. Farman adopted +the auxiliary planes used by the A. E. A. and modified them to suit his +ideas. + +~WONDERFUL RECORDS OF AEROPLANES~ + +Volumes could be, in fact, have been written about the exploits of +the first demonstrators of the practical heavier-than-air flying +machines,--of the crossing of the English Channel by Bleriot, of the +flights by Wilbur Wright at Rheims, France; of Mr. Curtiss’ winning of +the first Gordon Bennet International speed trophy and his flight down +the Hudson from Albany to New York; of Orville Wright’s flight at Fort +Meyer, and the death of Lieut. Selfridge who was flying with him. The +barest record of these interesting accomplishments would fill volumes. +Of the aeroplane proper it is enough to say here that since 1908 its +development has been too rapid for accurate recording. In strength, in +speed, in reliability, in size and carrying capacity, it has developed +at a remarkable rate. At this writing the speed record is about 130 +miles per hour; the duration record is more than 24 hours, non-stop; +the distance record is some 1,300 miles in one day; the altitude record +some 26,000 feet. New records succeed the old ones with such rapidity +that probably before this can be printed all these present records will +have been greatly eclipsed. + +[Illustration: + + AEROPLANE “RED WING” HAMMONDSPORT, N.Y. + + FIRST AMERICAN PUBLIC FLIGHT, MAR 12 1908] + +[Illustration: The biplane in which G. H. Curtiss flew from Albany to +New York in 1910.] + +Meantime the aeroplane has developed greatly in other directions. In +flying over land with the early types of machines many fatal accidents +occurred, particularly to the fliers who gave exhibitions everywhere +during 1909, 1910 and 1911. A majority of these accidents were +indirectly due to the fact that a very smooth surface is required for +landing a fragile machine running at high speed. The obvious expedient +was to develop machines capable of rising from and alighting upon the +water. + +[Illustration: SOME FAMOUS FOREIGN MONOPLANES + +A modern German monoplane.] + +[Illustration: The machine in which Bleriot crossed the English Channel +in 1909. A modified Langley type.] + +[Illustration: Rolland Garros and monoplane in which he flew across the +Mediterranean Sea in 1914.] + +~THE WONDERFUL FLYING BOAT~ + +During the winter of 1910 and 1911 Mr. Curtiss, who had continued +independent experiments upon the disbandment of the Aerial Experiment +Association, succeeded in producing the first machine to safely leave +and return to the water. For the development and demonstration of +this type of flying machine he was awarded the Aero Club of America +Trophy, and when during 1912 he produced still another type of water +flying machine, the Curtiss Flying Boat, he was again awarded the Aero +Club Trophy and also voted a Langley Medal by the directors of the +Smithsonian Institution. + +[Illustration: Different views of flying boat.] + +Not until the development of the flying boat did the general public +begin to take a participative interest in aviation, but as soon as the +comparative safety of this type of machine became apparent the new +sport began to be taken up rapidly both in this country and in Europe. +The experiences of naval fliers and amateurs alike went to show that +water flying offered not only the fastest and most comfortable mode +of rapid travel, but also the safest, for during 1913 several hundred +thousand miles were flown by navy aviators and amateur enthusiasts in +Curtiss water flying machines without a single serious accident. + +What aviation will mean to future generations,--even to this generation +in the course of a few years,--it would be foolhardy to try to guess. +Mr. Rodman Wanamaker already has agreed to furnish the financial +support for Mr. Curtiss’ attempt to build a machine to fly across the +Atlantic Ocean, from America to Europe. If the venture is successful it +is expected the crossing will be made in a fraction of the time taken +by the fastest Transatlantic liners. The discovery of new metals and +new manufacturing methods will certainly result in the development of +light motors that may be relied upon to run for days without stopping, +and automatically stable aeroplanes seem to be not far away. This will +result in overland flight as safe and sure as we now enjoy over water. + +[Illustration: INSIDE OF A MODERN FLYING BOAT + +Interior arrangement of modern flying boat, showing fuel tank and +instrument board.] + +[Illustration: Six-passenger flying boat hull. This machine will fly +1,000 miles without stopping for fuel.] + +[Illustration: FUN IN A FLYING BOAT + +Flying at speed of a mile a minute.] + +[Illustration: Monoplane flying boat, built for R. V. Morris.] + +[Illustration: In a flying boat on pleasure bent.] + +~GREATEST PRESENT VALUE OF AEROPLANE~ + +At present the greatest value of the aeroplane seems to be for +military reconnaissance and all the great powers are striving their +utmost to secure supremacy in the air. France, Germany, Russia and +England have to date spent millions in developing aeroplane fleets. +Only the government of the United States has failed as yet to +appreciate the military significance of the flying machine. If the +relative aeronautical strength of the world’s nations were represented +alphabetically the U. S. would naturally scarce have to change its +initial, U being slightly in advance of Z which would stand for +Zululand. But even with its modest equipment the navy fliers of the +United States proved the great worth of the aeroplane and the flying +boat, when during the recent trouble in Mexico the air scouts gathered +in a few minutes information that could only have been secured by days +of cavalry scouting before the advent of the flying machine. Indeed, +the name of Lieut. P. N. L. Bellinger, the most able of the naval +fliers at Vera Cruz, has figured more prominently in the despatches +from the front than that of any other officer connected with the +expedition. + +Flying seems certain in the very near future to take its place as the +fastest, safest and most comfortable mode of conveyance. The flying +boat will render quickly accessible the vast country lying along the +great rivers of South America, Africa, and Australia; it will bridge +the great lakes and the oceans; bring near together the islands of the +Pacific and Indian oceans. It will make imperative, because of the +speed with which distances will be traversed, of a language common +to all peoples; and treble man’s life without extending his years by +making it possible to see and do three times as much in the same length +of time. + +~TEN YEARS OF FLYING~ + +Ten years ago on that day, December 17, 1913, Wilbur and Orville Wright +made four flights on the coast of North Carolina near Roanoke Island, +a spot historic in America’s history as the site of the first English +settlement in the Western Hemisphere. + +[Illustration: Flying over military post in Curtiss biplane.] + +The first flight started from level ground against a 27-mile wind. +After a run of 40 feet on a monorail track, the machine lifted and +covered a distance of 120 feet over the ground in 12 seconds. It had +a speed through the air of a little over 45 feet per second, and the +flight, if made in calm air, would have covered a distance of over 540 +feet. + +Altogether four flights were made on the 17th. The first and third by +Orville Wright, the second and fourth by Wilbur Wright. The last flight +was the longest, covering a distance of 852 feet over the ground in 59 +seconds. After the fourth flight, a gust of wind struck the machine +standing on the ground and rolled it over, injuring it to an extent +that made further flights with it impossible for that year. + +[Illustration: + + 1900 + + 1901 + + 1902 + + 1905 + 1904 + + 1903] + +The gliding experiments of Lilienthal in 1896 led the Wright Brothers +to become interested in flight. The next four years were spent in +reading and theorizing. In the Fall of 1900 practical experiments were +begun with a man-carrying glider. These experiments were carried on +from the sand hills near Kitty Hawk, North Carolina. The first glider +was without a tail, the lateral equilibrium and the right and left +steering were obtained by warping of the main surfaces. A flexible +forward elevator was used. This machine was flown as a kite with and +without operator, and several glides were made with it. + +A second machine was designed of larger size, and many glides were +made with it in 1901. This machine was similar to the one of 1900 but +had slightly deeper curved surfaces. Experiments with this machine +demonstrated the inaccuracy of all the recognized tables of air +pressures, upon which its design had been based. + +In 1902 a third glider was constructed, based upon tables of air +pressures made by the Wright Brothers themselves. The lateral control +was maintained by warping surfaces, and a vertical rear rudder operated +in conjunction with the surfaces. Nearly a thousand gliding flights +were made with this machine. + +In 1903, the Wright Brothers designed a machine to be driven with a +motor. They also designed and built their own motor. This had four +horizontal cylinders, 4 in. by 4 in., and developed 12 h.p. Two +propellers, turning in opposite directions, were driven by chains from +the engine. After many delays the machine was finally ready and was +flown on the 17th of December, 1903, as related above. + +In the Spring of 1904, power flights were continued near Dayton with a +machine similar to the one flown in 1903, but slightly heavier. + +The first complete circle was accomplished on the 20th of September, +1904, in a flight covering a distance of about one mile. Altogether 105 +flights were attempted during the year, the longest of which were two +of five minutes each, covering a distance of about three miles. All of +the flights were started from a monorail. + +After September a derrick and a falling weight were used to assist in +launching the machine. + +[Illustration: + + 1908-9 + + 1910 + + 1910 + + MODEL R, 1910] + +~INTERESTING GOVERNMENTS IN FLYING MACHINES~ + +It was not till 1908 that the Wright Brothers found purchasers for +their invention. In that year they made a contract to furnish one +machine to the Signal Corps of the United States Army and to sell the +rights to their invention in France to a French company. In both cases +they agreed to carry a passenger in addition to the operator, fuel +sufficient for a flight of 100 miles, and to make a speed of 40 miles +an hour. + +After making some preliminary practice flights at their old experiment +grounds near Kitty Hawk in May, 1908, Wilbur Wright went to France to +give demonstrations before the French Syndicate and Orville Wright to +Washington to deliver the machine to the United States Signal Corps. +The machines used by Wilbur Wright had been standing in bond in the +warehouse at Havre since August of the year before. Owing to damage +done to the machine in shipment, it was not ready for the official +demonstrations until late in the year. + +Meanwhile Orville Wright in September, 1908, started demonstrations +of the machine contracted for by the United States Government. On the +9th he made two flights, one of 57 minutes, and the other one hour +and 2 minutes, world’s records. On the 10th and 11th, these records +were increased and on the 12th a flight of 1 hour and 15 minutes was +made. On the 17th, the tests were terminated by an accident in which +Lieutenant Selfridge met his death and Mr. Wright was severely injured, +so that he was not able to complete the tests until the following year. + +Four days after the accident, on the 21st of September, Wilbur Wright +made a flight of 1 hour and 31 minutes at Le Mans, France, which record +he improved several times during the following months, and on the 31st +of December, won the Michelin Trophy by a flight, in which he remained +in the air 2 hours and 24 minutes. + + + + +Where Is the Wind When It Is Not Blowing? + + +The answer is, of course, that there isn’t any wind then. To understand +this perfectly we must study a little and find out what wind is. In +plain words it is nothing more than moving air. + +If you make a hole in the bottom of a pail of water the water will run +out slowly. If you knock the whole bottom out of the pail filled with +water, the water will rush out before you know it. + +That is about what happens to make the wind. The air is constantly +full of air currents, like the currents you can see in a river. Down +the middle of the river you may notice a softly-flowing current going +straight. Along the shores there will be little side currents going +in all directions, and you may find some little whirlpools. That is +exactly what we should see in the air if we could see air currents. + + + + +Where Does the Wind Begin? + + +The movement of these currents of air leaves many pockets of space +where there is no air, and when one of these is uncovered the air +rushes in and creates a wind in doing so. These air currents are +continually pressing against each other to get some place else. They +change their direction according to the pressure that is being applied +to them. Sometimes the pressure will be very light in one part of the +air, many miles away perhaps, and then the air in another part, which +is under great pressure, will rush with great force into the part where +the pressure is light, and thus form a big wind. When the pressure +stops the wind stops. + +We have probably felt the wind which comes out of the valve of the +automobile tire when the cap is taken off to pump up the tire. It is a +real wind that comes out. The reason is that the air in the tube of the +tire is under great pressure, and when the opportunity is given to get +where the pressure is light it starts for that place with a rush and +comes out of the valve a real wind. + + + + +What Causes the Wind’s Whistle? + + +The whistle of the wind is caused very much like the whistle you make +with your mouth or the noise made by the steam escaping through the +spout of the kettle. You do not hear the wind whistle when you are +out in it. You can hear it when you are in the house and the wind is +blowing hard. When the wind blows against the house it tries to get +in through all the crevices, under the cracks of the doors, down the +chimneys, wherever it finds an opening. And whenever it starts through +an opening that is too small for it, it makes a noise like the steam +coming out of the spout of the kettle, provided the opening is of a +certain shape. + +Not all the noises made by the wind, however, are made in this way. The +wind in blowing against things makes them vibrate like the strings of a +piano or violin, and when things vibrate, as we have already seen, they +produce sound waves, which, when they strike our ears, produce sounds +of various kinds. The wind even on ordinary days makes the telegraph +and telephone wires hum, as you can prove to yourself by placing your +ear against a telegraph or telephone pole, and whenever the wind makes +anything vibrate, a great many queer sounds are produced, which often +frighten us more than they should. + + + + +Why Does the Air Never Get Used Up? + + +Simply because it is constantly being replenished. The three gases, +oxygen, nitrogen and carbonic acid gas, which are found in the air +about us, are constantly being used up. All living animal creatures are +at all times taking oxygen out of the air to live on. Certain microbes +are using up quantities of the nitrogen all the time, and the plants +live on the carbonic acid gas. But while these different kinds of life +between them use up the air, they give back something also. The plants +give off oxygen. The bodies of the animals and plants when they die +decompose, and as they are full of nitrogen, that is given back to the +air in that way, and then all living creatures are always throwing off +carbonic acid gas through their lungs, and thus everything that is +taken out of the air is put back again. The plants live on carbonic +acid gas, and give us back oxygen. The living creatures live on oxygen +and give off carbonic acid gas, and when they die their bodies put +back in the air the nitrogen which the microbes take out, and so, +consumption and production are about equal all the time. + + + + +Why Can’t We See Air? + + +We cannot see air because it has no color and is perfectly transparent. +If at times it appears that there is color in the air it is not the +air you see, but some little particles of various substances in it. +Sometimes you think when you look off toward a range of mountains or +hills, for instance, that the air is blue. You know the grass and trees +on the mountains are green, so it cannot be they that have turned blue, +and so you think the air is blue. But it is only the sunlight reflected +to your eyes from the little particles of dirt and other substances +which fill the air at all times which makes the blue that you see, and +not the air. + +Pure air is a mixture of gases without any color and is perfectly +transparent. Air is nearly entirely composed of a gas called +nitrogen--the remainder being oxygen with a little water and carbonic +acid gas, which latter is thrown off in breathing. This is, however, +but a very small percentage. + +Air has been and still can be reduced to a liquid state, and with +the use of it in this form many seemingly wonderful things can be +done, which are interesting to look at, but have not as yet become +commercially practical. + + + + +Why Does Thunder Always Come After the Lightning? + + +This occurs simply because lightning or light travels so much more +quickly than sound. Light travels at the rate of 186,000 miles per +second, and sound travels only at the rate of 1090 feet per second when +the temperature is at 32 degrees. Now, the thunder and lightning come +at the same time and place in the air, but the light travels so much +faster that you see the lightning often quite some seconds before you +hear the thunder. In fact, you can tell quite accurately how far away +from you the flash of lightning and clap of thunder are by taking a +watch and noting the number of seconds which elapse between the flash +of the lightning and the time when you hear the roll of the thunder. +If as much as five seconds elapse you can figure that it was about a +mile away from you, since sound travels only about 1100 feet per second +and there are 5280 feet in a mile. When the thunder and lightning come +close together you may know that it is near by, and when they come at +the same time you may be sure it is very close. When, therefore, you +see the lightning and then have to wait several seconds for the noise +of the thunder, you may rest easy about the lightning hurting you, +because you know then it is too far away to harm you, and when it is so +close that the lightning and thunder come simultaneously, there is no +use being afraid, because if you were to be struck you would have been +struck at the same instant or before you would have had time to notice +that the lightning and thunder come together. + + + + +How Big Is the Sun? + + +It is very difficult to gain a clear idea of how very large the sun +really is. We know from the scientists who have measured it with their +accurate measuring instruments that it is 865,000 miles through it, and +that at its largest part it is 2,722,000 miles around. Now, you can +see why I said it is very difficult to get a clear conception of the +sun’s size. A mile is quite a long distance to walk on a hot day. Now, +the earth is 8000 miles through. If there were a tunnel right through +the earth, like the subway, and you started to walk it, it would take +you 83¹⁄₃ days if you walked day and night without stopping to rest or +eat, if you kept going at the rate of four miles every hour. This would +be a long, hot walk, for, of course, the inside of the earth is hot, +as we have already learned. It would take an automobile, going at the +rate of 40 miles an hour night and day, about nine days to make the +trip through such a subway from one side of the earth to the other. +That makes it look like a pretty big old earth, doesn’t it? But let us +see what would happen if we started to do the same thing on the sun. +The sun is 865,000 miles through. If you were to walk through a similar +tunnel on the sun at four miles per hour it would take you 20 years, +not counting the stops, and an automobile going 40 miles an hour day +and night would take two years and a half to make the trip one way. + +The sun is ninety million miles from the earth and an automobile +travelling at the rate of forty miles per hour day and night on a +straight road, without stopping, would be 257 years in getting there. + +When we stop to think of how big the bulk of the sun is it is +altogether beyond us. We have a general idea that our earth is a pretty +large affair as worlds go, and yet we cannot conceive how much the +bulk of the earth amounts to. Still, the sun is so large that it could +contain a million worlds like our own. + + + + +How Hot Is the Sun? + + +We think the sun is pretty hot in summer when the thermometer goes +up to 90 degrees in the shade or out. We begin to get sunburned long +before it reaches that high. But right on the sun’s surface it is +between 10,000 and 15,000 degrees hot. That is, of course, a degree +of heat which we cannot conceive. How much hotter still it is on the +inside of the sun we don’t as yet know. It must be awfully hot there. + + + + +Why Is It Warm in Summer? + + +It is warm in summer because at that season of the year the heat rays +of the sun strike our part of the earth through less air. The blanket +of air which surrounds the earth is very much in comparison as to +thickness like the peeling of an orange and surrounds the earth in +just the same way. If you stick a pin straight into an unpeeled orange +you only have to stick it in a little way before you reach the juicy +part of the orange, but if you stick the pin in at an angle the pin +will travel a much longer ways through pure peeling before it strikes +the juicy part. Now, then, in summer the rays of the sun come down +to us straight through the peeling of air, and less of the heat is +lost by contact with the air, and that makes it warmer in summer. The +explanation also accounts for your next question. + + + + +Why Is It Cold in Winter? + + +In winter the heat rays of the sun strike at our part of the earth at +the angle at which you stick the pin into the orange when you wish to +make it travel through the most peeling. In winter the rays strike +the earth at such an angle that a great deal of the heat is lost in +travelling through the air, because they have to come through so much +more of the air. Of course, the sun’s rays strike some part of the +earth straight down through the peeling of air at all times, and at the +equator this occurs all the year round, so it is always summer there, +while at the North and South Poles the rays always strike the earth at +the greatest possible angle, and it is always very cold winter there. +In between, when it is neither hot nor cold, we have spring and fall, +due to the fact that the rays come down at an angle, but not so great +an angle. + + + + +Why Have We Five Fingers on Each Hand and Five Toes on Each Foot? + + +All animals, it seems, from a study of nature were started with ten +fingers and ten toes, the fingers originally having been the toes of +the fore legs. In a good many cases the environment in which animals +have lived has caused a change in the formation of the ends of the +limbs as well as in the limbs themselves. The horse, for instance, has +developed into a one toe or one finger animal, while a cow is a two +finger animal. The hen has only three toes on each foot and a part of +another. But if we go back into the history and examine how the horses’ +foot used to look we will find that he originally had five toes. The +same is true of the cow and also the hen. Something happened to cause +the change, for the rule of five fingers and five toes on the end of +each limb has been universal. If you examine a chicken in a shell just +before it is ready to come out, you can distinctly count five toes on +each foot and at the ends of the wings you will see five little points, +which under other conditions would develop into fingers, perhaps. +Some of these toes of the new-born chicken do not develop. It can be +accepted as a rule that creatures were intended in the original plan to +have five fingers on each hand and five toes on each foot, making our +count of tens, which is the world’s basis for counting, and has always +been. + + + + +Why Do We Have Finger Nails? + + +Finger nails and toe nails are only another phase of the development +of man from the animal that originally walked on four feet. Animals +that walk on all fours use the finger and toe coverings which in man +is the nail, to scratch in the ground, to attack enemies, and to climb +with, and our nails of the present day are what the development of man +into a civilized being has changed them to. At that, there are still +uses for finger nails and toe nails, or man in his changing to a higher +plane would have found a way to develop away from them. They are useful +to-day in making our fingers and toes firm at the end, and enable us +to pick up things more easily. The time may come when man will have +neither finger nails nor toe nails. + + + + +Why Are Our Fingers of Different Lengths? + + +There is no known reason why our fingers should be of different lengths +to-day; in fact, it is thought by some people that the hand would +be stronger if the fingers were all of the same length. Certainly, +however, the hands would not then be so beautiful, and it might not be +so useful. The human hand to-day is perhaps the most versatile thing +in the world. You can do more things with the hand than with any other +thing in the world. The probability is that the shape of the hand +to-day and the length of the fingers are the result of the different +things the human being has called upon the hand to do during man’s +development up to the present time. + +We must go back to the time, however, when man walked on fours, for +that is probably the real explanation. Originally man’s fingers were +of different lengths because all four-footed animals had the same +peculiarities. The shape and length of the toes and their arrangement +were the ideal arrangement for giving the proper balance and support +to the body, and in moving about and in climbing produced the best toe +hold. + + + + +Why Does It Hurt When I Cut My Finger? + + +It hurts when you cut your finger, or, rather, where you cut it, +because the place you have cut is exposed to the oxygen in the air, and +as soon as it is so exposed a chemical action begins to take place, +just as when you cut an apple and lay it aside you come back and find +the cut surface all turned brown. If the apple could feel it would +hurt also, because the chemical action is much the same. The apple has +a skin which protects its inside from the oxygen in the air, and you +have also a skin which protects you from the oxygen as long as it is +unbroken. + +What happens, of course, is this: When you cut your finger you sever +the tiny little veins and nerves which are in your finger. They are +spread all over your body like a net-work under the skin, close to the +surface in most places. The nerves when cut send a quick message to the +brain, with which they are connected, telling that they are damaged, +and the brain calls on the heart and other functions to get busy and +repair the damage along the line. There may be some hurt while this +process of repairing is going on, but the principal part of your hurt, +outside of what we call your feelings, is due to the fact that the +inside of you is thus exposed to the chemical action of the air. Then I +can hear you say next: + + + + +Why Don’t My Hair Hurt When It Is Being Cut? + + +It does not hurt to cut anything that has no nerves. There are no +nerves in the hair which the barber cuts. If he pulls out a hair it +hurts, because the root of the hair has nerves, which telegraph notice +of the damage to the brain. When a dentist takes out or kills the nerve +in your tooth you cannot have any more toothache in that tooth, because +there is no nerve there to send the message to the brain. You can cut +your finger nails without feeling pain, because they have no nerves at +the ends, but underneath, where they join the skin of the finger, there +are a great many nerves, and it hurts very much to bruise the nails at +that location. + + + + +Of What Use Is My Hair? + + +~WHY WE HAVE HAIR~ + +Your hair is a relic of the days when the entire body was covered with +hair, just like some animals to-day, to protect the body from the heat, +cold and wet. Man has, however, for so long a time worn clothes over +most of his body that the need of the hair to protect him from these +elements has all but disappeared, and so also has the hair, excepting +in such places as the top of the head and face and other exposed +parts. If you were to go out into the woods without clothes and live +a long time your body would probably again become covered with hairs. +The time is coming, however, it is believed, when human beings will +have no hair at all on their bodies. You have hair on your head, but +if you were to wear a hat or cap all the time you would soon be bald. +Hair is of no use to us to-day excepting to adorn our bodies and add +to our appearance. This it seems to do to-day, probably because we +are accustomed to seeing it, and will make no difference in our looks +relatively if the time comes when we have no hair at all. + + + + +Why Does My Hair Stand On End When I Am Frightened? + + +It does this under certain conditions, because there is a little +muscle down at the root of each hair that will make each hair stand +up straight when this muscle pulls a certain way. It is difficult to +say just how these muscles are caused to act in this way when we are +frightened. We know that when thoroughly frightened our hair will +sometimes stand straight up, and we know that it is this muscle at the +root of each hair that makes it possible, but why it is that a big +scare will make this muscle act this way we do not as yet know. + + + + +What Makes Some People Bald? + + +The chief cause of baldness is the lack of care of the hair. It is as +necessary for the roots of the hair to have a free circulation of +the blood and that the hair itself should have plenty of air as it is +necessary for the brain to have a good circulation. A great many men +become bald through wearing their hats most of the time. The hat pulled +down tight over the head presses against the scalp and interferes with +the circulation of the blood in the scalp. Then, also, many hats do +not have any means of ventilation, and that keeps the pure air away +from the hair. The hair then becomes sick and dies, just as flowers +wilt if you keep them away from the air. You will notice that women +do not become bald so easily. One reason is that even when the women +wear large hats, as they often do, there is plenty of room for the air +to circulate through the hair, even when the hat is on, and women’s +hats are not pulled down tightly on the scalp. Therefore, they do not +press on the arteries and veins in the scalp and interfere with the +circulation of the blood. Another reason why women do not become bald +is that the hair of women has long been their “crowning glory”; a man +likes to see a fine head of hair on a woman, and as women have long +tried to please men in every possible way, they take better care of +their hair than men do, because they like to have the men consider it +beautiful. + + + + +What Makes Some Things in the Same Room Colder than Others? + + +The objects in a room which has been kept at a given even temperature +of heat will be all the same temperature, because heat spreads from one +thing to another equally. + +Still, if you put your hands on various objects in such a room some +of them will feel colder than others. You touch the tiling of the +fireplace and that will feel cool to you. On the other hand, the +upholstered furniture will feel quite warm. The piano keys feel cool, +while the wood of the piano and case is warm. The difference is due to +the fact that heat or cold will run through some objects more quickly +than through others. It will run through the tiling on the hearth +and the piano keys more quickly than through the upholstering on the +furniture or the wood of the piano case. When you touch a thing with +your finger you supply some of the heat of your body to the object +through your finger. If the object is the tiling on the hearth or +the keys of the piano the heat runs through it quickly and you get a +cold impression in your finger. On the other hand, if you touch the +upholstery on the furniture, through which the heat runs slowly, you +get a warm feeling for the very same reason. Thus, anything which +carries the heat away from our contact quickly we call a cold feeling +object, and if the object touched does not carry the heat away so +quickly we call it a warm feeling object. + + + + +Why Does the Hair Grow After the Body Stops Growing? + + +The hair on our bodies is one of the things that is continually wearing +or falling away, and since, like the skin, it is necessary to protect +certain portions of the body, the hair keeps on growing long after the +grown up period has arrived. The skin is a very necessary protection +of the whole body, but is constantly being worn away, and is all the +time being replaced. Your hair falls out when it is not healthy. Unless +proper care is given to it, it will fall out and not grow in again, and +then we become bald. + + + + +Will People All Be Bald Sometime? + + +There is a theory that before many years have passed human beings +will lose all of the hairs which now grow on different parts of their +bodies, due to the fact that we wear so much clothing and keep so much +of our bodies away from the sunlight. If that time comes we shall have +a hairless race of men and women. + + + + +THE STORY IN A LUMP OF SUGAR + + +[Illustration: PREPARING THE GROUND.--PLOWING AND HARROWING WITH A +CATERPILLAR ENGINE. + +Sugar beets require deep plowing, ten to fourteen inches, or twice the +usual depth. When using horses, farmers are inclined not to plow deeply +enough to secure maximum results, and some of the factories have put +in power plows which turn six furrows and harrow the land at the same +time. They plow and harrow the land of beet farmers for $2.50 per acre, +which is about one-half of what it costs the farmers to plow equally +deep with horses. The traction engines also are used for hauling train +wagon loads of beets to the factory. In some localities farmers are +banding together and purchasing engines for plowing and hauling beets. +The outfit illustrated above costs about $4,500.] + +[Illustration: DRILLING THE SEED. + +Beets are drilled in rows, usually eighteen inches apart, 18 to 25 +pounds of seed being drilled to each acre. Practically all the beet +seed used in America is grown in Europe, principally in Germany, but it +has been demonstrated that superior seed can be produced in the United +States. Sugar-beet seed growing requires five years of the utmost +skill, care and patience, from the planting of the original seed to +the maturing of the commercial crop which is sold to the trade. The +factories contract for their seed for three to five years in advance, +sell it to farmers at cost price, and deduct the amount from the +payment for beets.] + +[Illustration: HOW THE BEETS ARE GROWN + +BLOCKING AND THINNING. + +When the beets are up and show the third leaf they should be “thinned.” +Unless thinned at the proper time the pulling up of the superfluous +beetlets injures the roots of the remaining ones. Scientific +experiments in Germany, where all other conditions were identical, +showed that one acre thinned at the proper time yielded 15 tons; the +next acre, thinned a week later, yielded 13¹⁄₂ tons; the third acre, +thinned still a week later, yielded 10¹⁄₂ tons; and the fourth acre, +thinned three weeks after the first, yielded 7¹⁄₂ tons. + +The men in the foreground are “blocking” the beets, leaving a bunch of +them every eight inches. Those in the rear are “thinning,” or pulling +up the superfluous beetlets, leaving one in a place, eight inches +apart.] + +[Illustration: READY FOR THE HARVEST. + +This field of beets yielded 20 tons to the acre. Ex-Secretary of +Agriculture James Wilson is convinced that when American farmers become +expert in beet culture they will average to produce more than 20 tons +per acre because of the superiority of our soils. The ideal factory +beet weighs about two pounds, and a perfect “stand” of such beets, one +every eight inches, in rows eighteen inches apart, would yield 43¹⁄₃ +tons per acre. The present average yield in the United States is about +10 tons per acre, while the hitherto “worn-out soils” of Germany yield +14 tons per acre, or 40% more than is secured from our “virgin soils.”] + +[Illustration: HUGE BINS TO HOLD THE BEETS AT FACTORY + +TOPPING THE BEETS. + +After the beets are plowed out they are topped or cut off by hand and +the tops are fed to stock, for which purpose they are worth $3.00 per +acre. They are topped just below the crown and the factories require +that they be so topped as to remove any portion which grew above the +ground, as such portion of the beet contains but a small percentage of +sugar. The beet will grow in length, and, if as a result of shallow +plowing or coming in contact with a rock it cannot grow downward, it +will grow upward and out of the ground, thus necessitating a deeper +topping and consequent loss to the farmer.] + +[Illustration: DUMPING CARS AT FACTORY WITH HYDRAULIC JACK. + +Beets arriving at the factory by rail from receiving stations either +are stored in bins until needed or are floated directly to the beet +washers. If to be used at once, they are dumped, as shown above, and +slide directly into a cement flume filled with warm water, which has +been pumped to its upper end, and is flowing in the direction of the +beet end of the factory. In whatever manner they may be received, they +first are weighed, and as they are dumped, a basket is held under them +to catch a fair sample of both beets and the loose dirt, which the +car or wagon contains. These samples, properly tagged, are conveyed +to the beet laboratory, where they are washed, and trimmed if not +properly topped, and the difference in the weight of the sample beets +as received and their weight when washed is called the “tare.” Whatever +percentage this amounts to is applied to and deducted from the weight +of the car or wagon load. A sample of these beets then is tested by the +polariscope for its sugar content and its purity; farmers often being +paid a stipulated price per ton for a beet of a given sugar content and +25 to 33¹⁄₃ cents per ton additional for each extra degree of sugar +which they contain. The tare rooms and the beet-testing laboratories +are open to any one, and in some localities the farmers’ associations +employ experts to tare and analyze each sample of beets.] + +[Illustration: MILLIONS OF BUSHELS OF BEETS + +FACTORY BEET BINS FILLED TO CAPACITY. + +As they arrive by rail from receiving stations, or by team, or traction +engines from the farm, beets are stored in bins or sheds, the capacity +of which ranges from 6000 to 35,000 tons per factory, depending upon +location and general climatic conditions. + +The bins are V shaped, about 3 feet wide at the bottom, 20 to 30 feet +at the top, and they are 20 to 30 feet high. As beets are needed, +beginning at one end of the bin the loose three-foot planks at the +bottom are removed one at a time, and with hooks attached to long poles +the beets are rolled into the flume or cement channel below, in which +they are floated into the factory. This is not only to save labor, +but to loosen up the dirt which attaches to the beets, thus partially +washing them. The water which is used in the flumes is warm water from +the factory.] + +[Illustration: TYPICAL AMERICAN BEET SUGAR FACTORY. + +These factories cost from half a million to three million dollars. +They consume from 500 to 3,000 tons of beets per day, and during the +“campaign,” which usually lasts about three months, will produce from +12 to 75 million pounds of granulated sugar. There are 73 of these +factories, located in 16 States, from Ohio to California. During the +operating season they give employment to from 400 to 1000 men each.] + +[Illustration: WASHING THE SUGAR BEETS + +CHEMICAL LABORATORY. + +In a beet-sugar factory each set of apparatus for performing a given +process is termed a “station.” In the chemical laboratory the juices +and products from each station are tested hourly to check up the +correctness of the work and to determine the losses of sugar in each +process in the factory.] + +[Illustration: CIRCULAR DIFFUSION BATTERY. + +After being floated in from the sheds the beets are elevated from the +flume to a washer, where they are given an additional washing before +being sliced. From the washer they are elevated and dropped into an +automatic scale of a capacity of 700 to 1500 pounds. From the scale +they pass to the slicers, where with triangular knives they are cut +into long, slender slices, which look something like “shoestring” +potatoes. These slices drop through the upright chute seen at the right +side of the picture, and are packed tightly into cylindrical vessels +holding from two to six tons each; the battery consisting of eight to +twelve vessels arranged either in a straight line or in circular form. +Warm water is run into these slices, and coaxes out the sugar as it +passes from one vessel to the succeeding ones. After passing through +the entire series of vessels the water has become rich in sugar, of +which it contains from 12 to 15 per cent, depending upon the richness +of the beets. It then is drawn off and is called diffusion juice or +raw juice. This is carefully measured into tanks and recorded. As this +juice is drawn off the vessel over which the water started is emptied +of the slices from the bottom, the exhaust slices containing in the +neighborhood of ¹⁄₄ to ¹⁄₃ per cent of sugar. These slices are carried +out from the factory in the form of pulp and fed to stock, as explained +later.] + +[Illustration: HOW THE SUGAR IS TAKEN FROM THE BEET + +CARBONATATION AND SULPHUR STATION. + +Warm raw juice is drawn into the carbonatation tanks and treated with +about 10 per cent milk of lime--about like ordinary whitewash. This +lime throws out impurities, sterilizes the juice and removes coloring +matter. Carbonic acid gas from the lime kiln is forced through the +lime juice in the tank, throwing out the excess of lime, converting it +into a carbonate of lime or chalk. Tests are taken here by the station +operator to show when the process is finished.] + +[Illustration: FILTER PRESSES. + +From the carbonatation tanks the juice is pumped or forced through +filter presses consisting of iron frames so covered with cloth that the +juice passes through the cloth as a clear liquid, leaving the lime and +impurities precipitated by it, in the frame, in the form of a cake. +This cake, after washing, is dropped from the presses and conveyed out +of the factory. It contains from one to two per cent of its weight +in sugar, which constitutes one of the large losses of the process. +It also contains organic matter, phosphate and potash, besides the +carbonate of lime, which makes it an excellent fertilizer, all of which +is used in Europe on the farm, but so far to too small an extent in +America.] + +[Illustration: EVAPORATING THE WATER FROM THE SUGAR + +EVAPORATORS. + +After a second, and sometimes a third carbonatation and filtration, the +juice is carried to the evaporators, commonly called the “effects,” +usually four (4) large air-tight vessels furnished with heating tubes +running from 3000 to 7000 square feet in each vessel. A partial vacuum +is maintained in these evaporators which makes the juice boil out at a +low temperature, thus preventing discoloration, and to a large degree +the destruction of sugar which will come about by high temperature. +There always is, however, some unavoidable loss of sugar in this +apparatus. The juice passes along copper pipes from first to last +vessel, becoming thicker as it does so. It comes into the first vessel +at 10% to 12% sugar and is pumped out of the last one so thick that it +contains about 50% of sugar.] + +[Illustration: VACUUM PANS. + +After a careful filtration, the juice that comes from the evaporators, +and is called thick juice, is pumped to large tanks high up in the +building, and from these is drawn into vacuum pans. These are large +cylindrical vessels from 10 to 15 feet in diameter and from 15 to 25 +feet high, with conical top and bottom, built air-tight. Around the +inner circumference they are furnished with 4- to 6-inch copper coils, +which have a heating surface of 800 to 2000 square feet. Exhaust steam +is used in the evaporators, live steam in the pans, the juice in both +being boiled in a vacuum to prevent discoloration and reduce losses. + +After considerable thickening by this evaporation, minute crystals +begin to form. When sufficient of these have formed, fresh juice is +drawn in and the crystals grow, the operator governing the size of +the crystals to suit the trade. If small crystals be desired, a large +quantity of juice is admitted at the outset, while if large crystals +are desired, a small quantity of juice first is admitted, and, as it +boils to crystals, fresh juice gradually is added to the pan, and the +crystals are built up to the desired size. The operator of this pan, +known as the “sugar boiler,” is one of the must important men in the +factory. The water furnished the condensers of these vacuum pans and +the evaporator goes to the beet sheds and is used for floating in the +beets. It amounts to from 3,000,000 to 8,000,000 gallons every 24 +hours, depending upon the size of the factory, and must be very pure.] + +[Illustration: HOW SUGAR IS GRANULATED + +FRONT VIEW OF CENTRIFUGAL MACHINES. + +The mass of crystals with syrup around them and containing about 8 per +cent to 10 per cent of water is let out of the vacuum pan into a large +open vessel called a mixer, beneath which are the centrifugal machines. +These are suspended brass drums perforated with holes and lined with a +fine screen. They are made to revolve about 1000 times to a minute, and +the crystal mass of sugar rises up the side like water in a whirling +bucket. The centrifugals force the syrup out through the screen holes, +leaving the white crystals of sugar in a thick layer on the inner +surface. These are washed with a spray of pure warm water and then are +ready for the dryer.] + +[Illustration: SUGAR GRANULATOR OR DRYER. + +The damp white crystals from the centrifugal machine are conveyed +to horizontal revolving drums about 25 feet long by 5 to 6 feet +in diameter. These drums are furnished with paddles on the inside +circumference, the paddles picking the sugar up and dropping it in +showers as the drum revolves. Warm dry air is drawn through and takes +the moisture out of the sugar, which now is ready to be put in bags or +barrels for the market.] + +[Illustration: BY-PRODUCTS OF THE SUGAR BEET + +CRYSTALLIZERS. + +The syrup that was thrown off from the crystals in the centrifugal +machines is taken back to the vacuum pan, evaporated in the same +manner as previously described, and from the vacuum pan goes into the +crystallizers to carry the process of crystallization as far as it will +go. These contain from 1000 to 1600 cubic feet of the crystallized +mass which remains in them from 36 to 72 hours, during which time it +is kept in constant motion by a set of slowly revolving paddles, or +arms, to facilitate further crystallization. From the crystallizers it +goes to the centrifugal machines, where the syrup is separated from the +crystals as before. The crystals are remelted and go in with the thick +juice for white sugar. The syrup, still containing a large amount of +sugar, goes out to be sold as cattle feed or to an Osmose or Steffens +process, where a portion of the remaining sugar may be recovered. This +lost syrup constitutes the largest loss in the entire process. It +contains all the impurities of the beet juice not removed by the lime. +These impurities prevent more than one and one-half times their weight +of sugar from crystalizing, and make what is called molasses.] + +[Illustration: A SEA OF BEET PULP. + +For a century the high feeding value of sugar-beet pulp has been +recognized in Europe, but until a few years ago millions of tons of +this valuable by-product rotted about American beet-sugar factories, as +shown above, because American farmers could not be made to believe it +possessed sufficient value to pay for hauling it back to the farm.] + +[Illustration: MACHINE THAT FILLS, WEIGHS AND SEWS THE BAGS OF SUGAR + +SACKING ROOM.--SHOWING AUTOMATIC SCALES AND SEWING MACHINE. + +After the moisture has been thoroughly removed in the granulators +or dryers, the sugar drops directly to the sacking room through +a chute, at the lower end of which the top of the double bag is +attached. The sugar flows directly into the sack, the flow being cut +off automatically with each 100 pounds, when an endless belt conveyor +passes the upright sack past the sewing machine at the proper speed and +the product is sealed ready for storage or shipment. + +While it requires from 400 to 1000 men to man a factory, not a human +hand has touched either beets or product since the beets were topped in +the field, and at no stage of the operation could flies or vermin or +filth come in contact with the product, which from the beginning has +been subjected to continuous high temperatures.] + + Pictures herewith by courtesy of United States Beet Sugar Industry. + + + + +How Can We Smell Things? + + +You do not need to be told what organ of the body we use in exercising +the sense of smell. You can prove that easily to yourself by getting +the nose within range of a distasteful smell. + +We do not use all of the nose to smell with, and the nose is useful to +us in other ways besides this. We use the nose a great deal in the act +of respiration or breathing, and it is also useful in helping us to +make sounds, form words, and, though you may not have known it, helps +our sense of taste. + +We smell things by means of the olfactory nerves which are located +within the nose. The entire interior surface of the nose is covered +with a membrane. The ends of olfactory nerves, or the nerves which give +us the sensation of smell, are in this membrane, and the air, which is +filled with the odor of things we smell, passes over this membrane, and +thus the ends of the nerves feel the odor and cause sensation of smell +in the brain. The nerves of smell do not, however, go all through this +membrane. + +There are other nerves in the nose, however, besides those which give +us the sensation of smell. These are also very sensitive and serve to +make the nose exercise other functions when the inside of the nose is +hurt or tickled. When a foreign substance, one of the many smaller +particles which are constantly floating in the air, gets into the +membrane in the nose, it irritates these nerves and often causes us +to sneeze, which is only nature’s effort to drive out this foreign +substance and clean out the nose. Smell is one of the lesser of the +five senses which we possess. It is one of what has been called the +chemical senses. The sense of smell does not act at any great distance. +This sense could be made of more value to us if we developed it. Some +people have a more highly developed sense of smell than others. The +lower animals have a much keener sense of smell than people. A great +many of them can follow a trail for miles merely by the smell of the +foot-prints, and it is said that a deer will note the presence of man +or any other animal that may subject him to danger even when miles +away, the odor being carried to him through the air. + + + + +How Do We Taste Things? + + +The sense of taste is closely associated with the sense of smell. In +fact we do a good deal of what we think is tasting by using our sense +of smell. A cold in the nose will sometimes destroy almost altogether +the taste of food, so that there is a very close connection between the +sense of taste and the sense of smell. + +The sense of taste comes to us through the tongue, which is the +principal organ of taste. The remainder of our sense of taste lies in +the surface of the palate and in the throat. As in the case of the +other senses, the sensation of taste is given us through nerves, the +ends of which are all through those parts of the tongue, the palate +and the throat, which contribute to this sense. More nerves of taste +are located in the back part of the tongue than on the front, and it +is said that when you have to swallow a bad dose of medicine it won’t +taste so much if you put it on the front part of your tongue and then +swallow, because there are so few tasting nerves there. The extreme tip +of the tongue, however, is very thickly covered with the ends of the +taste nerves. In like manner one could have the front end of the tongue +cut off and still retain most of the sense of taste. + +Now, in order to produce the sensation of taste, the substance to be +tasted must come in contact with something which mixes with it and +causes the sensation of taste. This is what happens when we taste +anything. The juices or liquids which are caused to flow when anything +is put into the mouth act on the substances which enter and give the +taste nerves a chance to taste them. Really the nerves of taste are so +placed in the mouth as to be regular guards or inspectors of what shall +go into the stomach. You can see how well they are arranged. In the tip +of the tongue quite a few of them; in the back part of the tongue a +great many nerves, for from there the food goes into the throat, which +delivers it to the stomach; then those in the palate and in the throat. +They are arranged so that the taste nerves have ample opportunity to +test what comes in and to give warning to the brain of what is being +sent to the stomach. Sometimes the things that come into the mouth +are so distasteful to the nerves of taste that they refuse to hand it +over to the stomach, but instead cause the distasteful substance to be +thrown out again immediately. + +It is said that a good rule to follow in eating would be to swallow +only such things as are pleasing to the sense of taste. On this +principle many children would decide to eat nothing but candy, but do +you know, if you tried that, the continuous tasting of sweets by our +sense of taste nerves would cause them to repel further insertion of +candy after a while. You know that too much of a good thing is bad for +you, and that is what makes you feel badly when you have eaten too much +of one thing. + + + + +What Happens When We See? + + +~HOW WE SEE THINGS~ + +Of course, it is the eyes with which we see things. When we think of +the things with which we see, we think only of eyes, which give us our +sense of vision, but there are certain forms of animal life which have +no eyes but which have what are called eye spots or eye points, which +are sensitive to light and which are merely spots. These eye spots +may be located in any part of the body, and are often found in great +numbers on the same body. These rude eyes are, however, not real eyes. +They are, as has already been said, sensitive to light, but are found +only in some of the very low forms of animal life which live in the +water. A real eye is an organ in which the parts are so arranged that +optical images may be formed. + +As animal life becomes developed to a higher scale, the parts which +contain the making of real eyes become more distinct although, of +course, the eyes themselves are not so highly developed as in man. One +of the first kinds of life which has eyes with a definite structural +character are the worms, snails, etc., though their sense of vision is +more or less dim. + +When we come to the family of mollusks, however, low down in the scale +of life though they are, we find them to possess eyes which enable them +to see almost as well as animals which have a backbone, although this +kind of eyes is constructed in a very different manner than the eyes +of vertebrate animals referred to. As we ascend the scale of animal +life in the study of eyes, we come next to the crustaceous, which is an +important division of animal life that embraces the crabs and lobsters, +shrimps, crawfish, and insects such as sand-hoppers, beach-fleas, +wood-lice, fish-lice, barnacles. The eyes of such animals are quite +developed, but the number that each will have varies. Some have only a +single eye and others two, four, six or eight, but only certain kinds +of this class of life have more than two eyes. The spiders generally +have the most. + +In vertebrates, which is the class of animal life to which we belong, +the number of eyes is almost always two and no more. The eyes are +formed in special sockets in the skull, which are called eye sockets +or orbits. This arrangement of placing them in a socket is of great +advantage because the eye is thus protected from chance of injury +except from one direction--the front. These animals have also eyelids, +eyebrows and eyelashes, which serve as a further protection to the eyes. + +The principal parts of the eye are arranged in a globe-like ball called +the eyeball. This eyeball is movable in the socket under control of +various muscles. The eyeball is almost surrounded by a membrane which +is opaque in most parts, but very transparent at the front. This +transparent portion of the surrounding membrane is called the cornea, +and is quite hard. This is the outside coat of the eye. The second +coat of membrane consists of parts of various names and contains the +iris. The third coat is the retina, which is the end of the optic nerve +entering the eye full from behind and expanded into a membrane which +spreads out over the second coat. + +The retina or optic nerve receives optical impressions focused upon it +by the crystalline lens. These impressions are carried along the optic +nerve to the brain, and the brain then receives the sensation of seeing +the image. The eyeball is hollow, and its three surrounding coats +form what is practically the same as the interior of a camera. The +crystalline lens of the eye acts the same as the lens in the camera. +This crystalline lens is suspended within the eyeball right in front of +the transparent opening in the front of the eyeball, and when the rays +of light strike this lens it focuses them on the retina, which is the +same as the film in your camera. + + + + +Why Can We Hear? + + +We can hear because nature has provided us with a very wonderful organ +called the ear and which catches the sound waves that come through the +air into the ear and make a part of the ear vibrate. + +In man and mammals the ear is generally found on the outside of the +body, but the principal part of the ear is located within the skull. +What we call ears are only the funnel-shaped extensions on the outside +of the head which are not so very important so far as hearing is +concerned, because they only help the real ear to hear more easily. The +outside of the ear gathers in the sound waves and, because it is much +larger than the little hole which takes the sounds in to the real ear, +we can detect more sounds by having this funnel-shaped arrangement on +the outside. + +The inside of the ear contains an eardrum or tympanum which is +separated from the outside part of the ear by a membrane. Behind this +eardrum is the real hearing part of the ear in a labyrinth containing +the nerves of hearing. + +Now, when a sound wave strikes the membrane which hangs over the +opening before the eardrum, the membrane vibrates and transmits the +sound wave through the eardrum into the inner ear which contains the +ends of the nerves by which we hear. These nerves, on receiving the +sensation, transmit it to the brain which thus records the impression +of sounds. + +As we descend the scale of animal life from the mammals downward, the +ear becomes a more and more simple organ. In the vertebrates which +are not mammals, there is no external ear at all, and we find great +simplifications of the ear the lower down in the scale we go. + + + + +What Is a Totem Pole For? + + +Before people had individual names, the savage people who lived in +clans or tribes referred to themselves in the name of some natural +object, usually an animal which they assumed as the name or emblem +of the clan or tribe. These names never applied to one individual +more than another, but only to the clan or tribe, so that everyone +in a tribe which had taken the “wolf” for its emblem was known as +“Wolf.” Later on they began to distinguish individuals by giving them +additional names characteristic of the individual, such as “Lonely +Wolf,” “Growling Wolf,” or other names. The name of this animal was +then the emblem of one tribe. They, therefore, placed this emblem upon +their bodies, their clothes, utensils, etc. Through this, these emblems +also became at times idols of worship and so they erected poles upon +which their emblems were engraved. The word totem is a North American +Indian word meaning “family token.” The tribes called themselves after +animals from which they believed themselves descended. + + + + +Where Does a Flower Get Its Perfume? + + +The perfume or smell of the flower comes from within the plant itself. +The perfume arises from an oil which the plant makes, and just as there +are many kinds of flowers, so almost every flower has a different +smell. Of course, flowers belonging to the same family or species are +likely to develop different smells. The oils produced are what are +known as the volatile oils, which means “flying oils,” because, if +extracted from the flower and placed in a bottle and the cork left out, +they will vanish into the air. Without this quality we could not, of +course, smell them at all. + + + + +Why Do Flowers Have Perfumes? + + +Man uses these oils to provide himself with perfumes, but the plant or +flower has another purpose than this. The perfume is not made for man’s +use, but for the use of the plant itself. In the plant and flower world +the smell of the plant which is in the flower is a part of the scheme +whereby plants reproduce themselves. + +Every plant in order to reproduce itself must produce a seed. The +flowers are in most cases the advance agent of the coming seed. Each +flower produces within itself a little powder called the pollen, but as +plants are like people--also male and female--they are dependent upon +each other for the production of a perfect seed. Some of the pollen +from the male plant must be mixed with the pollen of the female plant +before a perfect seed results. + + + + +How Do Flowers Produce Seeds? + + +Naturally, the nearest male plant to a female plant may be quite some +distance off. How, then, is the pollen from the male plant to mix with +the pollen of the female plant? In some cases it is the wind which +blows the pollen powder from one to the other, and this thus leaves the +development of a perfect seed from a perfect flower open to chance. In +the case of perfumed flowers, however, which are mostly low-growing +plants, the wind cannot be depended upon. So nature gives to such +plants the power to make the perfumed oil and the busy bee does the +rest. The perfume being a flying oil rises up into the air and attracts +the bee. He is gathering honey and visits in turn all the flowers to +which he is attracted. He lights on a male flower and gathers in his +honey, and incidentally acquires on his legs, without intending to do +so, some of the pollen of the male flower. Then he flies about to the +next flower, and to others, and sooner or later he will come across a +female flower of the same kind as that from which he secured the pollen +on his legs. When he thus enters the female flower, the pollen on his +legs mixes with the pollen of the same kind of the female flower, and +quite unintentionally the bee helps thus to make the perfect seed. It +is not a part of a bee’s business to do this carrying. It only happens +that he does this in connection with his regular business of gathering +honey. It is a wonderful thing which may be noted here that the pollen +from a male of any flower will not mix with the pollen of the female of +any other kind of flower, but that the same kinds only have attractions +for each other. Flowers are given these attractive perfumes in order +that they may attract the bees and other insects in this way. The +plants or flowers which grow closest to the ground have generally the +strongest and most far-reaching smells. This is so that they will not +be overlooked. + + + + +Why Are Leaves Not All the Same Shape? + + +Leaves are of different shapes because they belong to different +families of plants or trees. They are a good deal like people in this +respect. Hardly two people in the world look exactly alike, but there +is a distinct family resemblance in members of the same family. It is +difficult to say just what happens inside the tree to determine the +shape of the leaf and that causes them to possess different shapes +from others. The shape of the leaf is a mark of identification of the +family to which the tree or plant belongs, just as you can tell from a +dog’s ears and from other characteristics what his breeding has been. +In the case of plants and trees however it is quite probable that the +shape and texture of the leaves has been developed as the result of +the conditions under which the plant grows. A plant or tree throws +off oxygen and takes in carbonic acid gas through the surface of the +leaves. To thrive and be healthy it must secure just the proper amount +of this food and as the quantity of food taken in depends upon the +amount of surface exposed through the leaves, each particular tree or +plant has developed in its own direction in this respect until this +feature of their structures has been adjusted properly to their needs. +It is a good deal like the radiation of heat in your home. + + + + +Why Are Some Radiators Longer Than Others? + + +When the plumber gets ready to put in the radiators in the home he +figures the cubic measurements of the room and then puts in a radiator, +the outside surface of whose pipes, is in the right proportion to throw +off sufficient heat to fill the room or heat all the air in the room. +It requires a certain number of square inches of radiator surface to +heat each cubic foot of air space and a good plumber can figure this +to a nicety. If he puts in a radiator however that has not sufficient +number of square inches on the outside of the pipes, the room will +not be heated properly. In the same way, the trees, require that +their leaves have a certain amount of square inches of surface space +in proportion to the size of the tree, to enable them to do what is +required of them and this is arranged by nature so that the trees grow +naturally, and no doubt the shape of the leaves has something to do +with this. + + + + +What Makes Roses Red? + + +All roses are not red. Some are white and others pink or of still +another color. The color of the rose, and in fact the color of all +flowers is due to the way they absorb and reflect the sunlight. In the +case of the red rose, the something in the plant that determines the +color, absorbs all the other colors in the sunlight and reflects the +pure red rays and that makes the color of the red rose. You cannot see +the color of any flower when it is perfectly dark. That is because they +have no color of their own, but only the colors which they reflect when +in the sunlight or some other light. The question of colors is more +fully explained in another part of the book. + + + + +Why Do Plants and Trees Grow Up Instead of Down? + + +As a matter of fact plants and trees do grow downward as well as up. +There is a part of each called the root whose business it is to grow +down and take certain things necessary to the life of the tree out of +the ground. But the part we see above the ground and which is the part +we generally think of only when we think of plants or trees. + +The tree or plant, in order to grow properly, and eventually produce +flowers and perfect seeds, must have sunshine and carbonic acid gas, +and it is the business of the leaves and other parts above the ground +to get these out of the air for the good of the plant or tree. So they +start to grow toward the sun. It is easy to prove how a plant will turn +toward the light. Take notice of the plants in the flower pots at home. +Set one of them on the window sill inside the window where the sun can +shine on it and notice how quickly the leaves and branches will be bent +over against the window pane. Turn it completely around then so that +the plant leans away from the sunlight and watch it for a day or two. +Before long you will find that it has not only straightened itself +completely out but started to lean toward the window glass again so +as to get as near the sun as possible. Most plants, if kept where the +sunlight cannot touch them, will die. The sunlight is a necessary part +of their lives. + + + + +What Becomes of the Plants and Flowers in Winter? + + +A great many, in fact the large percentage of plants, live only during +one season. This kind of plant actually dies completely after, in the +natural course of growth and flowering, it has produced its seed which +is the method by which such plants are reproduced. Other plants only +appear to die in the winter. Parts of them, such as the leaves and +flowers actually die, but the roots and stalks of such plants do not +die in winter. The part that represents the life in them goes to sleep +and lies dormant until the light and warmth of summer bring forth the +leaves and flowers again. + +The flowers, however, always die and the same flowers never appear +again but others just like them appear in their places. + +Even in hot countries where there is no winter, the plants must go +through a period of rest or sleep, although this change is not so +marked in plants which grow in these hot countries. + + + + +How Can Some Plants Climb a Smooth Wall? + + +To get at the answer to this question, we should pick out one kind +of plant like the creeping ivy vine. If we examine same as it climbs +a brick wall, we find that it sends out little shoots which attach +themselves around the little rough places in the bricks of the wall +which, if examined under a microscope are quite large apparently--at +least they are large enough for the tiny creepers of the ivy to hold on +to. Of course, if there were only one little “shoot” to reach out and +take hold of the rough spots in the wall, the vine could not cling to +the wall, but the vine puts out a great many of these shoots--which it +would perhaps be best to call “clingers” and as each helps a little to +hold on, the great number all holding on together enable a quite heavy +vine to hang on to an apparently smooth wall. + +Some vines have actually the ability to send out little suckers which +are made on the same principle as the boys’ sucker (a circular piece of +leather with string attached to the middle with which a boy can pick up +stones) and such plants can cling to and climb up an almost perfectly +smooth wall. + + + + +What Are the Thorns on Roses and Other Plants Good For? + + +The thorns of roses and other plants which have thorns originally grew +for the purpose of enabling the plants to fasten themselves on to +other things thus helping them to climb. Many plants with thorns are +permitted to grow now in places where they can use their thorns for +climbing but many others with thorns are cut down by the gardener to +make the plants shapely and to make them produce more flowers and less +branches, but they keep on growing their thorns just the same. + + + + +Do Plants Breathe? + + +Yes, indeed, plants do breathe. To breathe is just as important to the +life of a plant as it is to a boy or girl. Plants do not have lungs +like boys and girls and grown up people, but they find it necessary to +breathe. You know, of course, that fishes breathe, but they haven’t any +lungs either, even though they belong to the animal kingdom. Fishes +do not, however, breathe the air in the same form as we do because +they must use the air which they find in the water. That is why we say +fishes drown when on the land. They cannot breathe air in the form in +which we are able to use it any more than people can breathe the air in +the water. + +Breathing, however, is necessary to all living things and the gas which +we take in when breathing is oxygen. There is oxygen in the water as +well as in the air. Things which live in the air take their oxygen out +of the air and things which live in the water get their oxygen out of +the water. For this purpose it is necessary for plants and animals that +live under the water to have a breathing apparatus especially adapted +for getting oxygen out of the water. + + + + +What Happens When Breathing Occurs? + + +The act of breathing consists really of two actions. Taking something +into the body and expelling something. Every living thing inhales and +expels in breathing. We take in oxygen and expel it again but when it +comes out it has added something to it and the combination or result is +carbonic acid gas--so we take in oxygen and expel carbonic acid gas. + + + + +How Do Plants Breathe? + + +The lungs of a plant, or what the plant breathes with corresponding to +our lungs, are located in the leaves of the plant. Under a magnifying +glass we can see the lungs of the leaf quite clearly. In addition to +this we know that plants breathe, because if we put them in a vacuum +where there is no air they die very quickly. The plant needs air or +it will suffocate just as any animal will suffocate under similar +conditions. Plants, however, do not make use of the oxygen as they +find it in the air. They live on the carbon which they find in the +air mixed with oxygen. What happens then is this. The plants take in +through their lungs in the leaves carbonic acid gas from which they +take the carbon and use it as food, and throw off the oxygen which +they cannot use. Human beings and other animals take the oxygen into +their lungs and use it and expel carbonic acid gas. The result is that +each kind of life is dependent upon the other. If it were not for the +plant life, men and other animals would find it difficult perhaps to +find sufficient oxygen in the air to keep them alive, and if it were +not for the carbonic acid gas which the animals throw off, plants and +other vegetable life would have great difficulty in finding sufficient +carbonic acid gas to go around. + + + + +Why Do Plants Need Sunlight? + + +Most plants, if placed where no light from the sun can reach them, will +die very quickly. To prove that a plant needs the sunlight we have +only to place it in a dark corner of the cellar and notice how soon it +dies. In fact if it were not for sunlight there would be no life on +earth at all. The plant or tree drinks in sunlight through the surface +of the leaves. In fact the ability to take in sunlight constitutes the +real life of the tree or plant. Leaves grow thin and flat in order +that as much surface as possible may be exposed to the sunlight. If +a leaf were curled up like a hoop only a part of the outside surface +would be exposed to the sunlight and the amount of life that a leaf +could supply to the rest of the tree would be much less. The leaf is so +constructed that when the sunlight strikes down upon its green surface, +it changes the carbonic acid gas which it drinks in, into its elements, +i.e., it takes out the carbon which goes into the body of the plant and +combining with other food and water supplied by the roots causes the +plant or tree to grow and then returns the oxygen part of the carbonic +acid gas to the air. + + + + +Why Does Milk Turn Sour? + + +The milk turns sour because a little microbe, known as the milk microbe +gets into it, and being very fond of the sugar which is in the milk, +turns this sugar into an acid. + +If we could keep milk entirely away from the air after the cow is +milked, it would not turn sour, but as soon as it is exposed to the air +these microbes which are constantly in the air, drop into the milk. +They are alive, although invisible to the naked eye. If when they drop +into the milk it is warm enough for them to get in their work so to +speak, they fall upon the sugar in the milk and turn it into the acid. +Their attempt to sour the milk can be overcome by keeping the milk at a +low temperature in the refrigerator, but as soon as the milk is taken +out of the refrigerator and left out long enough to become warm, the +microbe begins to work and the milk cannot be made sweet again. If the +milk is boiled as soon or shortly after the cow is milked, the sugar in +the milk is changed in such a way that the microbe cannot feed upon it. + +[Illustration: A PERSIAN RUG WEAVER AT WORK.[3]] + + [3] Pictures and descriptions by courtesy of Hartford Carpet Co. + + + + +The Story in a Rug + + +What Are Carpets and Rugs Made Of? + +The choicest wool of the world is used in the manufacture of carpet. +In order to give satisfactory service carpet must be made of wool that +is of a tough quality and has a long fiber. Such wool is not produced +in America, and the markets of the distant lands that supply it are +practically exhausted to supply the American manufacturers. Most of the +wool used comes from Northern Russia, Siberia and China. It is shipped +in bales. When it arrives at the mill there is much to be done before +the wool is ready for any process of manufacturing. + + +How Long Have People Used Carpets? + +The art of weaving stands foremost among the ancient industries. It +came into being in the sunrise lands of the East where color has +endless charm and variety and where figure is made to serve the purpose +of fact and fancy. The art of weaving rugs is older than Egyptian +civilization. Stone carvings made when Egypt was yet unborn were +reproduced in rugs. + +At what period the loom was first used is impossible to tell. An +ancient Jewish legend claims that Naamah, daughter of Tubal-Cain, was +the inventor of the process of weaving threads into cloth. There are +other indications that the ancient Hebrews were the first weavers. +Mythology also tells of beautiful maidens weaving exquisite patterns +for the gods. Most of us are familiar with the story of Jason who set +sail on the Argo in search of the Golden Fleece, arrived at the kingdom +of Aeetes, won the hand of Medea, the daughter of Aeetes, who eloped +with him after he had secured the coveted fleece. + +The first hands busy at the weaving craft undoubtedly were those of +women. Chaldean gossip, repeated in history relates that Sardanphulees, +an ancient Greek king, was often seen in woman’s garb carding purple +wool from which his wives wrought rugs for floor coverings for the +palace. Homer shows Helen of Troy setting the tale of her people’s +war in the woof of her web, and also tells with Virgil of rugs that +were laid under the thrones of kings or upon chariot horses. Ancient +Hindu hymns show that these people made their textile fabrics studies +of great beauty. The woman in the Proverbs of Solomon says: “I have +woven my bed with cords; I have covered it with painted tapestry from +Egypt.” One learns from the writings of Pliny of the large money value +of rugs in ancient times. He wrote at length of a vast rug displayed at +a banquet of Ptolemy Philadelphius, the value of which was placed at a +fabulous sum. + +A later writer tells of the love of Cleopatra for rich rugs and +tapestries that were woven in her palace or in the countries to the +East. On the occasions of her meeting with Cæsar and Antony, the +Egyptian queen enveloped herself in a superb rug which she had woven +especially for the purpose of showing her renowned beauty to the best +advantage. Akhar, emperor of Hindostan, spread a knowledge of the art +of weaving throughout India. + +The earlier phases of the art of weaving may be traced through the +land of the Pharaohs to Northern Africa, Southwestern Asia, and +finally into the dawn of the Aryan civilization. The loom has not been +materially changed, and it may be seen to-day as it was in the time +when the priests of Heliopolis decorated the shrines of their gods with +magnificent carpets and when Delilah wove the hair of Samson with her +web and fastened it with a wooden pin. The ancient weavers attained +high artistic standards in their fabrics. Pliny tells of Babylonian +couch covers that had all the beauty of paintings and sold for great +fortunes to the ancient Asiatic kings. + +In all ages fine rugs have been used for religious purposes. Early +writings describe the use of rugs on the holy cars of pilgrimage to +Mecca, at the tomb of the prophet at Medinah and throughout the mosques +of the Orient. The abbot Egelric gave to the church at Croyland, before +the year 892, two large rugs to be laid before the high altar on great +festivals. At later periods rugs were used for similar purposes in the +cathedrals of Southern Europe. + +The Oriental people ever have been devoted to symbols and naturally +wove them into their fabrics. Their textiles were made to reproduce +mythological stories in which the fauna and flora of a country figured +prominently. There was the symbolism of form, color and animal life, +of trees and flowers, of faith, and earthly and heavenly existence. +The symbols were made to illustrate the conflict between light and +darkness, the evolution of life, the decay of death and the immortality +that awaits the blessed in paradise. + + +What Do the Designs in Rugs Mean? + +Since many of the figures of ancient rug-weaving are retained in modern +rug designs, the following list of meanings of ancient Oriental symbols +used in rug-weaving may be interesting as a key to the stories that are +said to appear in many rugs of Oriental design: + + Asp--intelligence + Bat--duration + Bee--immortality + Beetle--earthly life + Blossom--life + Boat--serene spirit + Butterfly--soil + Crescent--celestial virgin + Crocodile--deity + Dove--love + Eagle--creation + Egg--life + Feather--truth + Goose--child + Lizard--wisdom + Palm tree--immortality + Sail of vessel--breath + Wheel--deity + Lion--power + Ass--humility + Butterfly--beneficence of summer + Jug--knowledge + Ox--patience + Hawk--power + Lotus--the sun + Pine-cone--fire + Zigzag--water + Leopard--fame + Sword--force + Serpent--desire + Bird--spirit + Owl--wisdom + Pig--kindness + +Such are the traditions that the makers of modern rugs must live up to. +The art of the centuries has been revealed in the rugs of many nations, +and the rug-maker of to-day must uphold the standards of an art that +undoubtedly takes rank with the great arts. Where a valuable painting +goes into the home of one millionaire, thousands of rugs made from +an original design of unquestioned art and beauty go into homes the +country over to give warmth, comfort and beauty, delighting housewives +and imparting a sense of coziness and elegance. + +According to students of the art of weaving, the perfection of this +art was attained about the sixteenth century, after many centuries of +slow growth. Since then weaving as an art has been broadened and given +a wider scope by means of processes invented for a cheaper production +of rugs in all the beauty of their original designs. But there also has +developed a modern school of rug and carpet designing that in itself +represents no mean standard of art. Many of the less expensive grades +of American rugs and carpets, for example, are of designs created by +artists of this modern school of weaving designs whose work is of a +high degree of artistic excellence. + +[Illustration: HOW OUR GRANDMOTHERS MADE RAG CARPETS + +MAKING THE OLD RAG CARPET.] + +A quarter of a century ago many homes had rugs woven by the housewives +with their spinning-wheels, or no floor coverings, except crude +cloths made of rags. These homes, of course, were those of families +in moderate circumstances, which to-day can have their attractive and +comfort-giving rugs of the less expensive grades of tapestry carpet, +Axminster or of the various other grades of carpet manufactured at a +range of prices within the financial reach of people of modest means. + +It is only a step from the ancient weaving of rugs, with all the color, +glamor and romance that attached to rug-weaving in the ancient days, to +the manufacture of rugs in America to-day. There is no romance attached +to the making of rugs and carpets in America, except the romance of +industrial achievement; but the American rug-maker is as careful of the +quality and beauty of his product as was the ancient weaver, and the +best standards of ancient weaving have been realized in the manufacture +of rugs and carpets in America to-day. + + +Why Did the Ancients Make Rugs? + +It is only a rug, several yards of woven threads, a design that few +can understand--a simple thing, to be sure; yet what a lot of history +and memories and traditions it carries! Merely a strip of carpet, with +strange figures, beautiful though meaningless, a product of modern +invention like many another, some may think. But the story of a rug may +go back through many centuries to ancient times of opulent splendor, +when wars were waged and kingdoms created and shattered for the beauty +of a woman; when gorgeous palaces were raised and great spectacles of +art were shown to inspire the world for thousands of years. + +Only a rug, but a relic of a rich and glowing past! For in those +distant days of war and pageantry, an era more classic than our own, +history and romance were woven into the rug. The patterns and designs +told great stories of wars and loves that swept nations away and +created great new empires and related vivid accounts of intrigue and +tragedy that determined history and inspired the immortal works of +poets and dramatists. The rug in the ancient times was also used for +religious symbolism, and sacred doctrines were inscribed in the woven +figures. + +Of all the arts none has been as close to the lives and history of the +peoples of the earth as the art of weaving. Songs and stories of these +peoples and their national achievements have been immortalized through +their woven fabrics. Generations have learned of the great deeds of +their forefathers through the historical accounts woven into rugs. And +in the days of the early Greeks, Hebrews and Egyptians and on through +the succeeding centuries until the middle ages the rug was used as a +symbolical part of state, religious and romantic ceremonies. + + +What Makes Some Rugs so Valuable? + +The reason many rugs are valued at so high a price in money is largely +due to the skill of the artist or designer, just as a painting becomes +valuable because the artist who painted it has succeeded in producing a +remarkable result. The question of rarity also enters largely into the +value of rugs. The great artist weavers of the past who worked for love +of their art rather than for the money they might secure by disposing +of their masterpieces, are dead, and they have had no successors. +Then, also, the rug becomes valuable by reason of the amount of time +and labor put into it. Many valuable rugs take years to produce, +because the artist must do all his work by hand practically and tie his +different colored yarns together just so, or the pattern will not come +right. These knots may occur every inch or sometimes even less than an +inch, and there will be thousands of hand knots in one rug. + +[Illustration: MAKING TURKISH RUGS.] + +[Illustration: THE OLDER THEY ARE THE MORE HIGHLY PRIZED + +The above is a typical Chinese rug, containing symbolical emblems. + +This is an antique and is of a class that sells sometimes as high as +$5,000, its rarity of design, beauty in colors, and scarcity enhances +its value.] + +[Illustration: This is an American machine-made interpretation of a +Chinese rug. The ground is a rich gold coloring, the figures being in +ecru, dark blue, terra cotta and light blue. It is a beautiful rug, and +one of the finest examples of loom-tufted goods ever produced.] + +[Illustration: WHERE THE BEST PERSIAN RUGS ARE MADE + +This antique Persian was made in the district of Kurdistan, in Western +Persia. The general effect is handsome, although the design is crude. +The ground is of a deep rich red, and top colors of dark blue and ecru. + +The most valuable Persian rugs come from Kurdistan, Khurasan, Peraghan +and Karman. The most highly prized come from Kurdistan. The pattern +does not show a uniform ground of flowers or other objects, but +looks more like a field of wild flowers in the spring, which is very +appropriate as a design for anything that is to be walked upon. It +is astonishing what wonderful artistic ability is displayed by some +of the members of these wild nomadic Persian people. The carpets and +rugs are woven on a simple frame on which the warp is stretched. The +woof, or cross threads, consist of short threads woven into the warp +with the fingers and without the use of a shuttle. Then a sort of comb +is pressed against the loose row of cross threads to tighten it. The +weaver sits with the back of the rug towards him, so that he depends +entirely on his memory to produce a perfect pattern.] + +[Illustration: This rug is an American copy of a typical Kurdistan. It +is marvellous how well the effect in colors and design are reproduced +in this domestic rug.] + +[Illustration: HOW WE IMITATE POPULAR DESIGNS BY MACHINERY + +This Tabriz reproduction has all the characteristics of the genuine rug +in both design and color. The ground is of a soft rose with figures +olives, ivory and deep blue.] + +[Illustration: This is a copy of an old piece of a rug in the +Kensington Museum, London, which is 500 to 600 years old. The design is +very interesting on account of the symbolical figures which cover the +ground.] + +[Illustration: WOOL-PICKING MACHINE.] + + + + +The Making of Carpets + + +How Are Modern Rugs and Carpets Made? + +The best way to learn of this is for us to take a brief visit to one +of the largest carpet factories, where we will assume we have already +arrived. + +There is a sharp whistle, then an outlet of steam, the clang of a bell +and a locomotive rolls around the curve of the spur-track into the +factory yard. Attached to it are several freight cars that only the +day before received their cargoes at the New York docks fresh from +steamships coming from foreign lands. Inside the yard, the engine comes +to a stop alongside a warehouse. Sturdy men unlock the doors of the +cars and begin pulling out bales of the imported wool. + +This is the first step in the evolution of a rug. Between the arrival +of the rough wool at the warehouse and the placing in the stock room +of the finished rug, splendidly woven after an artistic design shown +in attractive colors, many interesting processes are followed. It is +sufficient to state that few people looking at rugs of the Saxony, +or Axminster or Tapestry type realize the high degree of mechanical +science and artistic perception that have been brought to bear in the +manufacture of these rugs. + +After the arrival of the wool there are many steps to be taken until +the skeins of yarn receive their coloring treatment in the dye-house +and, at the bidding of the great machine, assemble themselves in the +beautiful designs that the artists have created. Though there are +many details of work in the development of a rug, they have been so +well mastered that the employes in charge of every stage of the rug’s +evolution give to their work a nicety of attention in little time that +careful training and scientific understanding alone can supply. + +The travel-stained covers of the bales are removed. The heavy bulk is +broken and the tightly-compressed bales loosened. Then the wool is fed +into the washing-machine, and after that goes into the picking-machine. +The process of cleansing the wool is an elaborate one, for it is so +full of dirt and grease that several waters and several operations are +necessary to its final appearance in a white and fleecy condition. +After the last washing the wool is lifted to a drying-room, where the +heat from steam-coils is forced through it by means of blowers. + +The wool now passes to the sorting-room, where the blends are carefully +made before it goes to the machine which tears the wool fibers apart, +and gets them in shape for the carding and combing processes. Next +the wool is blown into a spinning mill. The wool is now ready to be +converted into yarn. It passes through a picking-machine, which blends +the different grades of the raw material, selecting the strands as to +fiber and color. Then it is refined and purified. + +[Illustration: CARDING MACHINE] + +Through tubes the wool is forced to the carding-room by means of air +pressure. In passing through the cards it is carefully weighed to +secure evenness in the yarn. Leaving the carding machine, the wool +is taken to the floor above, where the big spools of yarn reach the +combing machine for the next process. This machine separates the long +from the short fibers. The strands of wool are still thick and must go +through another process before they are ready to be made into yarn. +They are finally united and given sufficient strength to stand the +weaving process. As the visitor sees the strands of yarn first appear +on the machine they resemble rolls of smoke. + +[Illustration: DYEING THE YARN] + +~HOW THE YARN FOR CARPETS IS DYED~ + +The yarn next appears on rows of spindles in the mule-room, six hundred +feet long, where the yarn is twisted and brought to its final stage. +The yarn now is ready for the dye-house. Here the atmosphere is very +dense. Clouds of steam rise from the many vats of boiling dyes. The +yarn receives the coloring for which it is intended, or is bleached +in an adjoining department, and then is transferred on poles to the +drying-room, after passing through a steaming process which sets the +color. Next it passes on an electric conveyor to the weave-shop. + +Considerable skill is required in the weaving process. The assembling +of the yarns and matching of colors require expert attention. The +skeins of yarn are wound on spools, which are put in sets back of the +looms, each color or set representing one “frame” of color in the rug. +By the famous Jacquard motion of cards each color wanted in the surface +of the rug is pulled up in its proper place, the other frame color +laying in the back of the rug. The mechanical process is a remarkable +sight. As the pattern forms itself from the mechanical devices, the +onlooker is struck with the wonder of it. + +[Illustration: HOW A CARPET IS WOVEN BY MACHINERY + +WEAVING A RUG BY MACHINERY] + +[Illustration: 10,000,000 YARDS OF CARPET PER YEAR FROM ONE FACTORY + +This picture shows the plant of one of the largest carpet factories in +the United States at Thompsonville, Conn. From the looms of these mills +are annually produced ten-million yards of the twenty-five different +grades of carpet manufactured by this concern. + +Imagine a strip of carpet across the United States at its widest +part, the Forty-second latitude--a strip of “Hartford Saxony”, say, +stretching from the Atlantic seaboard to the Pacific coast; and then +another carpet strip the length of the United States, where this +country is the longest--i. e., from the Northern boundary of the +state of Minnesota to the Southern boundary of the state of Texas; +then imagine one more strip stretching from Chicago to New Orleans, +and finally a connection between the two latter strips at about the +vicinity of St. Louis. + +With a mental picture of this vast country thus stripped with carpet, +you wonder if there is that much carpet in the world. It seems +incredible that this great sweep of land could be measured with +carpet--and yet enough material comes every year from the looms of one +carpet factory alone in this country to strip the United States East +and West, and North and South as indicated above.] + +The weave is now completed; the rug comes out. But it is rough and +has to be finished. It is passed through a machine that removes the +roughness of the face as a lawn-mower cuts away the top-grass. The ends +are finished, and the carpet is complete. + +~SOME DESIGNS STAMPED ON YARN BEFORE WEAVING~ + +The pattern of tapestry carpet is obtained by printing the colors +to appear in the design on the yarn which forms the face before the +weaving is started, by means of large drums. After all rugs leave the +weave-shop a force of skilled women examine them carefully to make sure +that there are no defects. Every yard of the annual output of carpet +and rugs is inspected five times before it leaves the factory. + +[Illustration: EXAMINING AND REPAIRING] + +[Illustration: PACKING FOR SHIPMENT] + + + + +Why Do I Yawn? + + +When you yawn, you do so because you have not been breathing quite +properly and for some reason or other your blood supply has not been +getting sufficient oxygen through the air which has been taken into +your lungs. Nature’s way, in this instance, is to call for a big intake +of air all at one time, and since it is important at such times that a +large quantity of air should be supplied to the lungs at once, nature +has so arranged matters that certain muscles shall cause you to open +your mouth wide and take in as much air as you can at one time, and +also has arranged so that it is almost impossible to keep from yawning +when the demand for it is once made. The yawn is controlled by a part +of our nerve structure which looks after the breathing apparatus. + +The satisfaction we feel after a wholesome yawn is due to the fact that +having replied to nature’s demand that we bring in more air, our blood +secures the oxygen which it needs and we feel the effect of better +blood in our arteries at once. + +A peculiar thing about the process of yawning is that one person in +a room yawning will quite likely set all or nearly all the others to +yawning also. There seems to be no explanation of this excepting that +when a number of people are in one room and one of them begins to +yawn, the others do so, not because they perceive the first yawn so +much as the probable fact that the air in the room has become so poor +that there is not enough good air for all the people in it, breathing +normally, and many of them are forced to yawn at about the same time. + + + + +Where Do Living Things Come From? + + +This is a big subject, but a very interesting one. To understand it +fully we must begin at the very beginning of the world. + +God made first of all the rocks, the mountains, the sun, the moon, the +stars, the soil, and put the water in the lakes, rivers and oceans. +This took a long time, but they had to be there before the living +things could begin to be. + + + + +What is Inorganic Matter? + + +This thing we have spoken of is called inorganic matter, which means +“without life,” and everything in the world which has no life is called +inorganic matter. These things do not die, and for that reason do not +have to be replaced. The form and appearance of inorganic matter and +its location is often changed by man or other causes, but even when man +burns the coal which he has dug up out of the ground in the furnace, no +part of it is destroyed. Some of it is turned into smoke and gas and +some of it is turned into ashes, while every other particle which went +to make up the coal originally is still in existence. It remains as +inorganic matter in some form or other. + + + + +Where Did Life Begin on Earth? + + +After the inorganic things had been made and the earth was ready for +life, the different kinds of living things which we find on the earth +began to exist. These are called organic objects, which means objects +“with life.” The first living things to appear were the bushes, the +grass, the garden vegetables, the flowers, trees, and all the kinds of +life which we ordinarily think of as growing things. + +This division of living things makes up what we call the vegetable +kingdom, and in a general way of classing it is the kind of life +which cannot move about from place to place and which has not a sense +of feeling, or any of the other senses, seeing, hearing, tasting or +smelling. + +After this division of life had been established the world was ready +for the other and more important form of life--the fishes, the birds, +cats, dogs, horses, cows, with others that we call domestic animals, +and also the lions, tigers, elephants and others which constitute the +division of wild animals. + +This kind of life was given some or all of the five senses, but not +all classes of animal life possess all these senses. Some of the lower +forms of animal life, like the oysters, clams, in the fish family, +cannot see, hear, smell or taste. They can only feel; others are able +to do more of these things, and many have all of the five senses. + + + + +When Did Man Begin to Live? + + +Man was not created until all the other living things on earth had been +started, and he was given additional powers so that he might become the +ruler of all the other living things, principally because he was given +a brain with power to think, reason and originate. + + + + +Why Must Life Be Reproduced? + + +Life must be reproduced because living things die. They have power to +live only for a certain length of time. The other life in the world is +used to provide food for man, and if there were no way of reproducing +life it would not be long before man had eaten all the vegetables and +the animals too, and would himself then starve to death. + +To avoid such a calamity God put into each living thing, both +vegetables and animals, a power to cause other things of the same kind +as itself to grow. This is called the power of reproduction. With this +power each kind of living thing can bring other specimens of the same +kind into the world and each kind of living thing can do this without +aid from any other kind of life. + +The trees, the flowers, and other kinds of vegetable life would +reproduce themselves without the aid of man, as would also the fishes +and other kinds of animal life. Man, however, just to have things +conveniently at hand, uses his power over other life to cause his +vegetables to grow near where he lives, and keep the animals which he +wishes to use as food in some place where he doesn’t have to hunt for +them every time he wishes meat for his table. This, however, he does +only with the animals which he has domesticated or tamed. When he wants +meat from the animals which are still wild he must hunt for them as he +used to do. + +Each kind of life has the power, however, to reproduce only its own +kind. If you plant a peach stone you will sooner or later have a peach +tree which will bear peaches, and these peaches from the young tree +will look and taste just like the peach whose pit or stone you planted. +There may be other kinds of fruit trees all about, and also trees which +do not bear fruit. All of the trees secure the food upon which they +live and grow from the same soil. Even the grass under your peach tree +eats the same things as your peach tree, but it remains always true +that things in the vegetable kingdom will grow only to be like the +thing from which it came. + + + + +Have Plants Fathers and Mothers? + + +The little trees grow up to be exactly like their fathers and mothers +(for they have fathers and mothers), which is something all living +things must have. These are not the same kind of fathers, or mothers +either, that a boy or girl has, exactly, but they are parents just the +same. So far as the trees, flowers and plants are concerned we call the +parents father and mother natures, which is a term used merely to keep +you from confusing vegetable life fathers and mothers with the regular +kind. + +In the vegetable kingdom you cannot always see these father and mother +natures, which enable them to reproduce their kind of life, but +everything in the vegetable and also in the animal kingdom has them. + + + + +How Do Plants Reproduce Life? + + +In the spring we put seeds into the ground and later on plants grow up +where the seeds were planted, and later the flowers come. The seeds +contain the baby plants, which come to life, and after bursting the +covering of the seed, unfold and grow up into plants if placed in the +ground, where they can obtain the proper amount of warmth and moisture +to give them a start. + + + + +Why Do Plants Have Seeds? + + +To get at this subject in the best manner we must study first how +plants produce seeds and what happens. The power in a plant to make +another plant like it grow comes from the flower. Ordinarily we think +of the flowers as beautiful to look at and delightful to smell, but +the flowers do not grow for the mere purpose of being beautiful, but +are for a more useful purpose--to develop a seed which, when planted, +will produce another plant. The machinery for producing a perfect +seed is in the flower or blossom. Every flower has a definite plan of +construction. The leaves and colors vary, but the plan for a perfect +flower is always there. The petals which are generally colored are +called the _crown_. When you pluck off the petals you see a number +of green leaves at the bottom where the petals were attached. These +form what is called the _calyx_, and help to hold the petals in place. +Inside the flower are little stems which grow to the petals. These are +called _stamens_. Every one of these little stems is hollow, and if +you split one open you will discover a _fine powder_. This powder is +called _pollen_, and is the “father” nature of the plant. In the calyx, +the part we had left after we plucked off the petals, is the “mother” +nature of the plant. The main part of the mother nature is the stem of +the flower called the _ovary_, and this is where the seeds grow. These +seeds in the ovary, however, will not become perfect seeds unless some +of the pollen from the “father” nature of the plant touches them and +fertilizes them. + +At the proper age of the flower some of this pollen powder passes into +the ovary and fertilizes the seeds and makes them good seeds. This is +only one kind of flower, however. In this kind the father and mother +natures are in the same flower. In other kinds of plants the father and +mother natures are found on different parts of the same plant. + + + + +Why Does an Ear of Corn Have Silk? + + +The corn plant is one of this kind. You know what it looks like--a tall +plant, generally six or seven feet high. The ears of corn grow out of +the side of the corn stalk. The ear is covered with husks and out of +the end of the ear hangs a bunch of brown silk threads which we term +corn silk. Up at the top of the plant you will see the tassel, but +you may not have known that this is the flower of the corn plant. The +tassel or flower in this case contains the “father nature” of the corn +plant, and the ear of corn contains the “mother nature.” The husks on +the outside of the ear of corn protect the grains of corn on the ear +inside and keep them tender. The ear of corn is really the ovary of +the corn plant, because that is where the seeds grow. You will guess, +of course, that the grains of corn on the ear are but seeds of the +plant. Were you to examine one of these ears of corn on the plant when +it had just started to form you would find no kernels on the cob, but +only little marks which indicated where the grains of corn are expected +to grow, but if you want to know, then, how many grains of corn were +expected to grow on the ear, you could easily tell by counting the +little silk threads which you see on the cob and which stick out over +the end. There will be a thread of silk for each grain of corn that is +expected to grow. + +Every grain of corn must receive some of the pollen powder from the +tassel or father nature at the top of the corn plant or it will not +develop into a nice large, juicy kernel. + + + + +How Does the Pollen Touch the Grain of Corn? + + +Before the kernels of corn grow the tassel is in bloom. The wind blows +and shakes the pollen powder off of the tassel and the powder falls +on the ends of the silk which stick out of the little ear of corn to +be. Each thread of silk then carries a little of the powder down to +the spot on the ear where it is attached and thus the grain of corn +receives the fertilizing necessary to develop it into a ripe seed. +If you leave the ear of corn alone the kernel will eventually become +yellow and hard and can then be planted and will produce other corn +plants. Man, however, finds the ear of corn a delightful food, if taken +at a time when the seeds are fully grown but not yet ripened into +perfect seeds. At this stage the grains of corn would not grow up again +if planted, because they have not yet become perfect seeds. + + + + +Do Father and Mother Plants Always Live Together? + + +We come now to the kinds of plants on which the “father” and “mother” +natures are on different plants of the same kind. At times they will +grow side by side, at other times they will be in the same field, but +very often they grow at quite a distance from each other. In some +instances the nearest father tree will be even miles away from the +mother tree of the same kind. But in any event the pollen from the +father nature must reach the mother nature of the plant or tree before +a perfect seed can be produced. In cases of this kind the father nature +will be on one tree or plant and the ovary or mother nature on another. +The wind helps out nature in some of these cases by blowing the pollen +of the father plant to the ovary of the mother plant. In many other +instances the bees and insects help. + + + + +Why Do Flowers Have Smells? + + +Where the bees do this it is because the bee has been visiting the +flowers in his search for honey. They do not fly from flower to flower +for the purpose of uniting the mother and father natures of plants, but +they help the flowers incidentally while getting the honey for which +they are searching. In gathering his honey the busy bee will go all +over the father flower and get his legs all covered with pollen powder. +Sooner or later he comes to a mother flower of the same kind of plant +or tree from which he has father pollen on his legs, and, still bent on +gathering honey, he incidentally rubs the pollen powder on to the ovary +of the mother flower and the fertilization takes place. The wonderful +thing about this is that the father pollen of one kind of a plant will +not fertilize the mother nature of another kind of plant. To illustrate +this, if a bee carrying pollen on his legs from a walnut blossom visits +the mother blossom of a hickory tree the pollen of the walnut would not +affect the hickory blossom, but would still have the proper effect on +the first walnut mother blossom he visited. + +This is how life in general is reproduced among the plants and trees. +Life in the vegetable kingdom has no sense of feeling or any of the +other senses, but this kind of life is still true to its own nature +and is a wise thing in the plan of creation, because, since all seed +will produce only plants like those from which the seed came, man can +control the growth of the vegetables and fruits he needs as food. He +knows when he plants corn that he will get corn in return, because +perfect seed never makes a mistake. It would mix things up terribly for +man if this were not so, because man might then plant one thing and +find another thing growing. It would be a sad thing to plant wheat and +find thistles growing. + +In order that seeds may grow they must be planted under conditions that +suit the kind of vegetable life in the seed. Man has to study and learn +what these conditions are. + +If a seed is planted too deeply the sun may not have a chance to warm +the ground to that depth, and if it is planted too near the surface it +may become too warm and be killed by the sun. When planted under the +proper conditions the seed soon begins to grow. It grows upward toward +the sun to get light and air, and it sends roots down into the ground +to get food and moisture. + +The life in the vegetable kingdom is soon able to take care of itself. + + + + +How Are Fishes Born? + + +The next step in the study of the reproduction of life brings us to +the animal kingdom. The first thing we discover in this section is +that in the animal kingdom father and mother natures are almost always +separated. In plants and trees these parent natures are sometimes in +the same flower, often separated, but on the same plant, and in other +instances on different plants miles apart. What we must remember, then, +is that in the case of plants it is given more or less to the chance of +wind or other circumstances to bring the parent natures together. + +In the animal kingdom there are a few cases where the mother and father +natures are found in the same living object, as in the oyster and +clam families, one of the lowest forms of animal life. These have but +one of the five senses--that of feeling. This class of animals--the +cold-blooded animals--includes the fishes, and in most members of this +class the father and mother natures are separated and in different +bodies. Step by step from now on we enter higher forms of animal life, +and through each step we find a greater difference between the father +and mother natures, and in the animal kingdom we speak of the father +and mother natures as “_male_ and _female_.” In the animal kingdom, +too, what we have previously called the seed is known as the _egg_. +Seeds and eggs are the same so far as their usefulness is concerned, +but we say eggs in the animal kingdom to distinguish from seeds in the +vegetable kingdom. + +Fish have eggs, then, and it is from the eggs that little fish are born +into the world and grow to be of eatable size. You recognize the eggs +of the fish in the “roe,” which is eaten as food. Not all fish eggs are +used as food, however. + +In the fish world the eggs are developed in the body of the female +fish. Each little round speck in a “shad roe” is one egg, and there +are many thousands in a single “roe.” Each egg will produce a little +fish, under favorable conditions. These eggs develop in the body of +the female fish in winter. In the spring, which is the time in which +most living things are born, and, therefore, the time for hatching out +fish eggs, all of the fish swim from the deep water where they live in +winter to the places where the water is shallow and warm, and in these +shallow waters the female fish expels the eggs from her body where the +sun can get at them and hatch them by warming them. After the female +fish has thus laid the eggs, the male fish swims over the eggs as they +lay in the water, and expels from his body over them a fluid which is +white in appearance and which fertilizes the fish eggs. If any of this +fluid fails to reach some of the eggs it is not possible for the sun to +bring them to life. + +When the eggs are laid and fertilized the mother and father fishes swim +away and they never see their children or recognize them as such, even +if they meet them later in life. The parent fish do not act like other +fathers and mothers, and they do not need to, because as soon as a baby +fish is born he is able to find his own food and needs no help from +father or mother to teach him how to find it or enable him to grow into +a real fish. + +Of course, many of the tiny fish are eaten by other fish and not all +the eggs which the mother fishes lay hatch into live fish, because, if +they did, the waters would be so crowded with fish that there would not +be any room for the water. A single female fish will lay millions of +eggs in a year, and if each egg developed into a fish there would be +far too many. + +This order of animals, which includes turtles, frogs, etc., is the +cold-blooded class of animal life. They have only part of the five +senses. They all can feel and some of the fishes can see and hear, but +a great many of them, particularly those kinds which live on the bottom +of the ocean, cannot either see or hear, and some members of the fish +family cannot even swim. + +The thing to remember about fishes in connection with the reproduction +of life is that the mother fish must select a place which is favorable +to deposit the eggs, but after that her responsibility ceases. The +father merely fertilizes the eggs, and then his responsibility ceases. +The little fish look out for themselves as soon as they are born and +never know what it is to have a father or mother to look after them. + +When we study the next higher form of animal life we find that the +young ones have to be looked after, and that this becomes more +necessary as we ascend the scale of animal life until we reach man, the +most intelligent of all animals and yet the most helpless of all at +birth. + + + + +How Birds Are Taught to Fly. + + +The next step brings us to the birds. Before they can look after +themselves the little birds must learn how to search for food and the +kinds of food good for them. They have to learn the habits of their +kind of life. The higher you go in the study of animal life the greater +seem to be the dangers which surround the young animals and the longer +it takes to teach them how to look after themselves and what to do for +themselves. + +The bird family includes not only the robins, larks, sparrows and +pigeons, but also the ducks, geese, and chickens, etc. We are all more +or less familiar with birds’ eggs, and if not we know what a hen’s egg +looks like. The eggs of the bird family are laid in nests, which is the +first sign of home building in the animal kingdom. + +The birds are the first of the large class of warm-blooded animals. +The egg here represents again the reproductive power. The eggs, too, +form in the body of the female bird, but are laid in a nest which the +parent birds build together. Now this is the first step away from the +fish family. The fish looks for a suitable place to lay the eggs and +then goes off and leaves them. The birds, however, have to make a +nest in which to deposit the eggs. The fish, as you remember, depended +upon the warm sun shining on the shallow water to hatch out the eggs, +thus depending on an outside force to supply the necessary warmth. In +the bird family the mother bird must cover the eggs with her own body +and keep them warm until they hatch out. Then, too, the father and +mother birds feed the young until they are strong enough to fly and +find food for themselves, and so the mother and father birds look after +their babies until they are old enough to look after themselves. When +this time arrives the old birds cease to bother about the young ones +altogether. The fishes never act like parents after the baby fishes +are born, because the little fish are able to look after themselves +right away. The parent birds are a good deal like fathers and mothers +for a time, but only so long as it takes them to teach their little +bird children to look out for themselves. Then they forget the children +completely. + +It requires but a few days and no parental care to hatch out a family +of baby fishes and no attention at all after birth. It requires several +weeks and much patience for the parent birds to hatch out their eggs, +and it involves care and attention for several weeks to teach baby +birds to take care of themselves. + +This being a father or mother in the animal kingdom becomes a greater +responsibility in every step as we get closer to man, and when we reach +man we find him to be the most helpless offspring of all at birth, and +that it takes more time, care and attention to bring up a human child +to maturity than any other animal. + + + + +What Makes the Hollow Place at One End of a Boiled Egg? + + +This hollow place on the end of the boiled egg (sometimes it shows on +the side) is the air which is put inside of the egg when it is formed +so that the little chicken will have air to breathe from the time it +comes to life within the egg until it becomes strong enough to break +the shell and go out into the world. There is also food in the egg for +him. When you boil the egg this pocket of air within the shell, which +would have been used up by the chick if the egg had been set to hatch +instead of being cooked for breakfast, begins to fight for its space +and pushes the boiling egg back and forms the hollow place. + +The purpose of the air in the egg is a good thing to remember when we +come to study the higher forms of animal life from the standpoint of +how they reproduce themselves. + +The mammals are the next higher form of animals. The babies of this +class of animals must be fed for several weeks or months before they +are ready to come into the world. + +A little chicken is ready to come out of the egg almost as soon as it +comes to life, and, therefore, needs only a little air and food before +it is strong enough to peck its way out, but the babies of mammals +begin to live months before they are ready to come into the world, and +they need a great deal of air and food during this time. This class +includes the dogs, horses, cows, cats and all other animals in the +Zoo and in the woods. The name mammals means the same as “mamma,” and +indicates an animal which must be fed from the body of a female mammal +even after it is born. + +In this class the eggs are retained within the body of the female +animal instead of being laid in a nest or some other place, as in +animals of lower classes, after being fertilized by the male animal, +so that the baby animal may secure its food and air from within the +mother’s body after the life within the egg is begun. + +The mother’s body supplies the necessary warmth to develop the life +of the little animal in the egg, just as the birds supplied this with +their bodies. In the bird class it only takes a few hours to give +the little bird sufficient strength to peek his way out, but in the +mammal class it is a long time before the baby animal is strong enough +to come out into the world, and even after it is born the babies of +mammals require a great deal of care and attention before they are able +to look out for themselves. During this period the animal secures all +of its food from the breast of the mother animal. + +Another reason why the eggs of mammals are retained within the bodies +of the females is the need for protecting the young animals from +enemies. In the animal kingdom each kind of animal preys upon another +kind. They attack and devour each other and are constantly in danger. +If, then, mammals laid eggs in nests and sat upon them to hatch them +out, the mother animals sitting on the nests would be continually in +danger of attack from their enemies. They would either have to flee +and subject the nest and its contents to the danger of destruction or +else stay and fight, and perhaps be destroyed. But by carrying her egg +within her body the mother mammal is able to move about from place to +place and protect her baby. + + + + +Is Man an Animal? + + +Men, women and children belong to the “mammal” class of animals. The +offspring of the human family is the most helpless of all animals at +birth. The young of most kinds of mammals can stand on their legs +shortly after being born, but the human baby requires months before it +can stand up. A baby horse can also walk within a few hours, but human +children do not begin to walk until they are more than a year old. + + + + +Why Cannot Babies Walk as Soon as Born? + + +The human baby has a great many more things to learn than a horse baby +before it is safe for him to go about alone. It takes time for the +brain to develop, and if a baby could walk before the brain had even +partially developed it would only get into trouble. + +This, then, is what we have learned about the reproduction of life +and the reasons for its being different in different classes of life. +First, we had the division of organic life into the vegetable and +animal kingdoms. Life in the vegetable kingdom has none of the five +senses, for plants cannot see, hear, feel, smell or taste. They cannot +move from place to place, but remain where they grow until destroyed +or removed. On the other hand, all animal life has at least one of +the five senses--feeling. The oysters and clams belong to this class. +Starting with this level of life in the animal kingdom we find that as +we go on up through the different classes we find each class able to +do things which make it superior to the class below it, until we reach +the human mammal, who can do most of all. And, further, that since each +class as we go up in the scale of life has greater ability to do things +than the class beneath it, so in each case the task of the parents +in preparing their offspring for their kind of life becomes greater, +and the period during which the offspring is learning becomes longer +and longer until we reach the human family, in which we find that +parents have the greatest responsibility, and the children are the most +helpless of all animals, but that in the final result man has a right, +on account of his superior qualities, to be the ruler of the other +creatures of the world. + + + + +What Are Ball Bearings? + + +Some years ago a gentleman in trying to find some way to reduce the +friction, which is constantly developed to a certain extent, even when +the axle is oiled, discovered that if between the axle and the inside +of the hub a circle of steel balls were arranged, so that the hub of +the wheel did not touch the axle at all, but rested on the little balls +which in their turn touched the axle, that a great deal of the friction +was eliminated. This proved to be a wonderful invention, and when this +combination is arranged and oiled, there is hardly any friction. + + + + +Why a Gasoline Engine Goes + + +[Illustration: FIG. 1.] + +As you know, gasoline is a very inflammable fluid, and will explode if +placed too close to fire. + +This explosive quality is the basic principle of the gasoline engine. +By admitting a small quantity of gasoline vapor into an enclosed +cylinder, and exploding it by means of an electric spark, repeating +this operation continuously, the engine is given a regular rotary +motion. + +Look at Fig. 1. Starting from the gasoline tank, the fluid is fed +into the ‘carburetor’, which is a sort of atomizer. Here the gasoline +is mixed with air, and broken up into a very fine spray, in which +condition it will explode readily. + +The engine will not start of itself. Its fly-wheel must first be turned +by hand, or by some other outside force, until the first explosion +takes place. After this its action is automatic. + +As shown in Fig. 1, the fly-wheel is being turned, and is drawing the +piston down the cylinder, which in turn sucks gasoline vapor, (shown by +little arrows) through the ‘intake valve’. This ‘intake valve’, and the +‘exhaust valve’ on the opposite side of the cylinder, are opened and +closed at the proper time through the action of the gears shown in the +illustration. + +Passing to Fig. 2, the fly-wheel in turning has drawn the piston to +its lowest point, and is now shown forcing it up the cylinder. This +compresses the gasoline vapor in the cylinder to a density at which its +explosion produces the greatest amount of power. The intake and exhaust +valves are both closed. + +~WHAT CAUSES THE EXPLOSION IN A GAS ENGINE~ + +Fig. 3 shows the explosion. The cylinder has been filled with +compressed gas, and the piston has again started on its downward +travel. The spark plug, set in the top of the cylinder, makes a spark +every time an electrical current passes through it. A switch on the +engine permits the current to pass to the spark plug only when the +engine is at this position in its action. (Fig. 3.) The consequent +explosion drives the piston downward with great force, turning the +fly-wheel, which by its weight continues the rotary motion after the +downward impulse of the piston has been expended. + +Fig. 4 shows the fly-wheel, still turning, forcing the piston up and +thus expelling the burned gases from the cylinder through the exhaust +valve, held open for this purpose. From this position the engine +goes again to that of Fig. 1, and through 2, 3, and 4, continuously, +exploding every second revolution, and giving a regular rotary motion +to the fly-wheel. + +[Illustration: FIG. 2.] + +[Illustration: FIG. 3.] + +[Illustration: FIG. 4.] + +The illustrations show a one-cylinder motor, but these engines can be +built with two or more cylinders, arranged to explode at different +times, thus giving very smooth action to the fly-wheel and main shaft. + +Aeroplanes, almost all automobiles, various pumps and other machinery +are driven by gasoline engines. The rotary motion can readily be +transmitted by chains or gears to the propellor of an aeroplane or +motor boat, or the wheels of an automobile. It is only in the past few +years that the gasoline engine has reached its present high state of +perfection. + +[Illustration: THE BEGINNING OF AN AUTOMOBILE + +CRANKCASE SHOWING BEARINGS. + +The heart of the automobile is the engine. It is built around the +crankcase, which is its foundation or base.] + +[Illustration: CRANKCASE WITH CRANKSHAFT AND FLY-WHEEL ADDED. + +The crankshaft serves the same purpose in an automobile as the pedals +do on a bicycle. + +The fly-wheel on the end helps it to keep turning at an even speed.] + +[Illustration: Gasoline vapor is exploded in the cylinders. This pushes +the piston down, and as the piston is connected to the crankshaft it +starts the crankshaft turning. + +The piston and the rod that connect it to the crankshaft are just like +the feet and limbs of any one riding a bicycle. + +Cylinders showing piston in place and connected to crankshaft.] + +[Illustration: The gears or “cog-wheels” are for running the fan, the +pump and other parts.] + +[Illustration: THE HEART OF THE AUTOMOBILE + +Cylinder added to crankcase. + +The cylinders are next bolted down to the crankcase, the pistons and +crankshaft having been connected, as shown in Fig. 3. A cover is placed +over the gears to keep them clean.] + +[Illustration: An oil pan or reservoir is attached to the bottom of the +crankcase to hold oil for the engine.] + +[Illustration: The carburetor furnishes the gasoline vapor for the +cylinders. It is connected to the engine by a crooked pipe called the +intake manifold. + +After the gasoline has been exploded a valve opens and allows the +burned gases to escape through another pipe, called the exhaust +manifold.] + +[Illustration: Oil is poured in the spout which is at the left of the +carburetor. It runs down into the reservoir and is pumped up through +the engine a little at a time. + +Oil pump and filler added to motor.] + +[Illustration: THE POWER PLANT OF AN AUTOMOBILE + +The electric generator makes electricity to be used for starting the +engine and lighting the car.] + +[Illustration: The magneto gives an electric spark, which explodes the +gasoline in the cylinders. + +The water pump keeps water flowing around the cylinders to prevent them +from getting too hot. This water comes back to the pump through the +radiator at the front of the car. Wind blows through the radiator and +cools off the water. The tire pump on up-to-date cars is run by the +engine. It does not pump except when the gears, which are shown in the +picture, are pulled together.] + +[Illustration: An electric motor starts the engine by turning the +fly-wheel. This makes it unnecessary to get out and crank the car by +hand.] + +[Illustration: SECOND STAGE OF CONSTRUCTION + +The transmission is added. + +The transmission makes it possible to reverse the car. It also enables +the driver to go into high-speed gear when on level roads and low-speed +gear for starting and for pulling hills.] + +[Illustration: Double-drop pressed steel frame. + +The frame on which the car is built.] + +[Illustration: Addition of semi-elliptic and three-fourths-elliptic +springs to frame. + +Large springs are placed at the front and rear of the frame. They make +the car ride smoothly.] + +[Illustration: Adding the front axle.] + +[Illustration: READY FOR THE WHEELS + +Showing addition of full-floating rear axle.] + +[Illustration: Completed engine and transmission is next fastened to +the frame and connected to the rear axle by the drive shaft.] + +[Illustration: Showing addition of gasoline tank and gas lead to +carburetor.] + +[Illustration: Showing how steering gear is connected.] + +[Illustration: WHAT THE COMPLETED CHASSIS LOOKS LIKE + +Wheels are next added to chassis.] + +[Illustration: Completed chassis with radiator added. + +The water which keeps the engine from getting too hot is pumped around +the cylinders and then through the radiator. The wind blows through +the little openings in the radiator, and cools off the water. Then the +water is pumped around the cylinders again.] + +[Illustration: The steps and fenders are next attached.] + +[Illustration: THE MARVELLOUS GROWTH OF TWENTY YEARS + +The finished car.] + +[Illustration: GASOLINE AUTOMOBILE. + +The first American-built automobile, now in Smithsonian Institute, +Washington, D. C., where this photograph was taken. The rude carriage +that was a curiosity twenty years ago and less--the vehicle that vied +with the two-headed calf and the wild man of Borneo at the county +fairs--was the beginning of the greatest transportation aid since the +birth of civilization. Because of it our standards of living have +become higher. It has broadened the horizon of all of us. + +Built by Elwood Haynes, in Kokomo, Indiana, 1893-1894. Equipped with +one-horse-power engine. Successful trial trip made at speed of six +or seven miles an hour, July 4, 1894. Gift of Elwood Haynes, 1910. +262,135.] + +[Illustration: When an automobile passed you twenty years ago.] + +[Illustration: HOW AUTOMOBILES HAVE IMPROVED + +LEFT SIDE VIEW + +RIGHT SIDE VIEW + +A new exhibit in the Smithsonian Institute, officially known as +“Exhibit Number 56,860,” is attracting a great deal of attention from +visitors to the National Museum. It consists of a complete Haynes +six-cylinder unit power plant, and has been given a position at the +side of the original Haynes “horseless carriage,” where the striking +contrast shows the remarkable improvement that has been made in motor +design and construction during the past twenty-two years. + +The most important features of the power plant are shown clearly and +comprehensively by having sections cut away from the various parts, so +that the visitors to the Institute are enabled to see the mechanical +construction, and the relation of the component devices. + +On the right side of the engine, the intake and exhaust manifolds +are shown in their natural position. A full vertical section of the +Stromberg carburetor gives a good idea of how the gasoline is mixed +with the air and supplied to the cylinders. The Leece-Neville generator +has its casing cut away to give a view of the windings and cores. +Numerous windows have been cut into the crankcase to disclose the +crankshaft construction and the oil reservoir. The transmission gears +are also shown in this manner. + +Most of the electrical equipment is shown clearly on the left side of +the motor. Here an interesting feature is the full vertical section +of the American Simms high-tension dual magneto. A half section has +been removed from the rear cylinder, and the piston as well, to +give a glimpse of the interior construction. A large portion of the +Leece-Neville starting motor casing has been cut away. The cover-plate +on the switch controlling the starting motor has been replaced with a +glass cover to display the method of completing the circuit from the +battery to the motor. A skeleton selector switch is mounted at the rear +of the transmission case, instead of its usual position on the steering +wheel. The electric gear-shifting mechanism is made visible by using a +glass plate for the top cover-plate on the transmission.] + + + + +Why Does the Heart Beat When the Brain Is Asleep? + + +Under ordinary conditions the heart beats are controlled by certain +nerve cells which are located within the heart itself, and these cause +the heart to beat even while the brain is asleep. This explains why +the heart beats when the brain is asleep, and the fact that the brain +when asleep does not exercise its functions, shows how necessary this +arrangement and the control of ordinary heart beats is. If this were +not so, we should not be able to live while asleep. It is just like +the management of a great business in this sense. The general manager +of a great business has control of the entire works, but there are +occasions when he must be thinking of only one thing in connection with +the business, and so he must have his organization so complete, that +the parts which he cannot be thinking about at the time will do their +work just the same. So he surrounds himself with competent assistants, +who look after certain departments while he is busy or away or asleep, +and if anything goes wrong while he is away, he calls on special forces +to set things right. Now, the brain is the general manager of the whole +body and has these nerve cells in the heart as a sort of assistant +manager to look after the heart beats in ordinary conditions, and to +keep the heart going while he is asleep. But, by reason of his office +as general manager, the brain has a special way of sending orders to +the heart through special nerves which run from the brain down each +side of the neck to the heart. There are two pairs of these special +nerves. One pair, if set in motion, will make the heart beat faster, +and the other pair will make the heart beat more slowly. + + + + +Why Do Our Hearts Beat Faster When We Are Running? + + +When you start running, the brain knows at once that your legs and +other parts of the body will need more blood to keep them going, and +so the brain sends down orders through his special nerves which make +the heart beat faster, to get busy, and they do. Then when you stop +running, your heart is beating faster than necessary--there is really +an oversupply of blood being pumped through your system for the time +being, and that makes you uncomfortable, until the brain sends word +through the other set of nerves to the heart to slow down the heart +beat. It is better to stop running gradually, to give the heart a +chance to get back to its normal beat gradually also. + + + + +Why Do I Get Out of Breath When Running? + + +This is also caused by your brain in its efforts to keep up your supply +of good blood. We breathe to take air into the lungs, where the blood +which has once been through the arteries and comes back on its return +trip to the heart, is exposed to the air in the lungs, before going +back into the heart. The air which we take into our lungs purifies the +once used blood and makes it into good blood again. When you run the +heart pumps blood into your arteries faster to enable you to run. Thus +also, the arteries send much more blood back to the heart through the +veins, and this must be purified by the lungs before going back into +the heart. To attend to purifying this extra amount of spoiled blood +the lungs need more air, and thus you are made to breathe in more air +for the purpose. Unless you are in good training--your wind in good +condition as we say--it is almost impossible for you to supply the +lungs with enough air for the purpose, but whether you can do it or +not, the lungs call upon you for more air, and cause you to try to get +it, and that is what makes you get out of breath. + + + + +Why Does My Heart Beat Faster When I Am Scared? + + +The natural tendency of a scared creature is to run or fly. The effect +of being scared has the same effect on the brain that your starting +to run has. The brain is always as quick as you are, and knowing that +when you are scared your actual or natural inclination is to run, it is +merely getting you in shape so that you can move or run fast. + + + + +Why Does Cold Make Our Hands Blue? + + +Your hands appear blue when cold because the veins which are near the +surface are filled with impure blood which is purplish in color. Your +hands become cold because there is not sufficient circulation of warm +red blood going on to keep them warm. The blood in circulating through +your body sends warm red blood through the arteries, and this is +returned to the heart through the lungs by way of the veins. The veins +carry only used-up blood or what is left of the good red blood when the +arteries are through with it. Its color is a purplish blue. + +When your hands are blue it means that circulation of good red blood +has practically stopped--the red blood is not flowing from the heart +through the arteries in sufficient quantity and there is no color in +the arteries, as the blood from the arteries has practically all gone +into the veins. The veins are full to purplish blue blood, and this +makes the hands look blue, because there are a great many veins in the +hands close to the surface. + + + + +Why Do I Get Red in the Face? + + +Now, when you rub your cold blue hands together, you start the +circulation going again, and that brings the red blood into the +arteries, giving you the healthy red color again. When you run hard to +get red in the face because you are causing an unusual amount of red +blood to flow through your whole body by your violent exercise. Some +people with an extraordinary amount of circulation are red in the face +all the time. This is because of the presence of a great deal of blood +in the arteries, or because the walls of their arteries are so much +thinner than others that the red blood shows through more easily. + + + + +Is Yawning Infectious? + + +Yawning is infectious to the extent that other habits are. The desire +to yawn which comes to us when we see some one else does so comes under +the heading of suggestion. The power of suggestion is greater than many +of us realize. We are great imitators of each other. When one of us is +downhearted, we are apt to become happy and glad simply by being with +other people who are happy and glad. If enough people one at a time +tell a perfectly well man that he looks sick, he will actually feel +ill, provided he does not suspect a game is being played on him. So a +good actor carries his audience with him. He can make them laugh or cry +almost at will, and if he yawns, his audience will begin yawning. + +Often, however, there is no acting connected with the yawning of the +first person. Then the yawn is caused because the person is not sending +enough good air into the lungs for purifying the blood, and the yawn is +only nature’s way of making us take an exceptionally deep breath of air +in at one time. This lack of sufficient good air in the lungs may not +be due to the poor breathing, but to the amount of bad air in the room. +In such cases it is quite likely that other people in the room yawn +when one of them starts it because they all begin to feel the need of +more good air at about the same time. + + + + +What Makes Me Want to Stretch? + + +The necessity or desire to stretch comes to us because certain parts of +the body are not receiving the proper amount of blood circulation and +it is these parts that we stretch at such times. If you have ever been +to a ball game, you know, of course, that it has become customary for +the crowd, no matter how large, to stretch its legs and arms during the +last half of the seventh inning. In fact, that has come to be a fixture +at ball games and is universally known as the “stretch inning.” Now, +it is not so much the result of a desire to encourage the home team as +the natural following out of nature’s laws that originally started this +practice. The end of the seventh inning at a ball game generally means +that the crowd has been sitting quite still for the greater part of an +hour and a half, just long enough for the circulation to become poor +in parts of the body, and the custom of stretching at a ball game thus +comes from the necessity of getting a little more speed into the action +of the heart to increase the blood supply. + +In other words, the stretching constitutes a mild form of exercise. You +will notice the ball players themselves do not stretch themselves in +the last half of the seventh inning. They are getting enough exercise +without that. + +It is natural, however, for us to stretch as we wake up from sleep +after having lain quietly in one position for one or more hours. It is +nature’s way of causing the heart to work faster. + + + + +What Happens When I Stretch? + + +What happens is simply this. When you stretch your arms and legs, you +squeeze the arteries and veins which are a part of your arms and legs, +much as happens when you pull on a piece of rubber tubing. The tubing +becomes flat instead of perfectly round, and it is not so easy to send +water through a flat tube as through a round one. Just so with the +heart. It is the heart’s business to send blood through the arteries +at all times, and when you make them flat the heart’s job becomes just +a little harder, and it goes to work beating just a little faster to +overcome this extra difficulty. By that time you are through stretching +and the heart is busy pumping blood a little faster than ordinarily, +and that is what makes you feel so good after you have stretched. + + + + +Why Can We Think of Only One Thing at a Time? + + +If you are asking the question intelligently, you must know that to +think means to concentrate, and in that sense we can only think of one +thing at a time, because it takes all of that part of the brain which +is used for thinking for just one thing. To give close attention to any +one subject means to turn the entire brain force practically in one +direction. To let other things pass through the mind at the same time +may appear not to interfere with the one thought, but they do, and our +conclusions suffer accordingly. + +You can be doing something with one part of your body, while engaged +in thinking of one thing, but only such things as are more or less +mechanical as the result of habit, such as walking, or moving the +arms--things which the parts have done so often that actual attention +by the brain is not absolutely essential. Take for instance, the fact +that a man in deep thought on one subject will sometimes walk up and +down the room or along the sidewalk. He can do this walking and still +think concentratedly, but if he stubs his toe on the leg of a chair or +on a rough place in the walk, his thought is broken, because the brain +immediately takes itself out of the thought and pays its attention to +the toe that was stubbed. + + + + +Why Do I Turn White When Scared? + + +Simply because, when you are scared or frightened, the blood almost +leaves your face entirely. Under normal conditions, the red blood which +is flowing through the arteries of your face, gives the face a reddish +tinge, and your face becomes white when you are frightened, because +then the blood leaves the face. It is quite singular, but when you are +really frightened, whatever the cause may be, the human system receives +such a shock that the heart just about stops beating all together. When +your heart stops beating of course the flow of the blood from the heart +stops and then there is no supply of fresh red blood coming through the +arteries under the skin of your face. Therefore you look white--the +color your face would be if no blood ever flowed through your arteries +and veins. Some people have faces so white they look as though they +were scared all the time. This is not because they have no blood +flowing through the veins and arteries in their faces, but because +their supply of blood is less than other peoples, and sometimes because +the walls of their arteries and veins are much thicker than the average +that the color of the blood does not show through. There are also many +people who have so much blood in their systems all the time, and the +walls of whose arteries are so thin, that they look at all times as +though they might be blushing. + + + + +What Makes Me Blush? + + +Anything that will make your heart send an extra supply of blood into +the arteries and veins which supply your face with blood, will make you +blush. Embarrassment will do this. So will anger generally, although +sometimes people get so angry that the blood is driven out of their +faces. In this case they are so angry that their heart has stopped +beating, practically. + + + + +What Occurs When We Think? + + +When we think the mind is acting on sensations; it is receiving, in +conjunction with memories of sensations it has previously received. +Sensations as they reach the mind arouse the mind to activity and, as +soon as the sensation is received, the mind begins to compare the new +sensation with sensations received at previous times, and by putting +things together reaches a conclusion. + +When you are thinking you are really trying to call upon memory to +help you. You know the thought of one thing calls up another, and this +leads to something else. This association of ideas is the faculty which +enables us to think consecutively and accurately. It is the business of +the mind to receive the sensations that enter it and arrange them in +their proper places. That memory of past sensations is the important +part of thinking, is proven by the fact that when we have forgotten a +thing we are unable to think what it was. + + + + +Can Animals Think? + + +For this reason if animals have memory they should be able to think. It +is now believed that many animals have to a certain extent the power to +remember. + +A dog will recognize his master even though he has not seen him for +years. We might think he does this by his highly developed power of +smell, but if his master has come from a direction opposite to that +from which the dog first sees him, he could not have tracked him by his +smell. A dog will recognize his master from quite a distance, so he +must have to a certain extent the ability to remember or the power of +association of ideas, which amounts to the same thing. Again, a horse +that once belonged to the fire department, even though now hitched to a +milk wagon, will have the impulse to run to the fire when he hears the +fire gong. And an old war horse will prick up his ears as he used to +when he hears the bugle call. + + + + +Why Do I Sneeze? + + +You sneeze sometimes when you look up at the sun or at a bright light. +There does not seem to be any real good explanation of why looking at a +bright light should make you sneeze. It is due to the connection there +is between the nerves of the eyes and the nose. You generally blink if +you look at a bright light suddenly, and the blinking process stirs the +nerves inside of the nose to make you sneeze. + +You know, of course, that the start of the sneeze is inside of your +nose. The nose is, besides being the organ of smell, the channel +through which we take air into the lungs, when we breathe properly. +The nose is lined with membranes, back of which are a net of very +small nerves which are extremely sensitive. The membranes are placed +there to catch and hold the impure particles of matter which come into +the nose when we take in a breath of air, and sneezing is only one +effective way of cleaning out the nose. It is brought on only when some +particularly difficult job of nose-cleaning has to be done. Pepper up +the nose will make you sneeze quickly, because pepper produces a very +great irritation inside the nose, and the nose goes to work at once to +get rid of it in the quickest possible manner as soon as the pepper +comes in. Other things have the same effect. Sometimes a cold in the +head causes you to sneeze. The sneeze in that event is merely nature’s +effort to clean out the nose when other efforts have failed. + +There are many suggestions for stopping a sneeze before it takes place, +after you feel it coming on, such as putting the finger on each side of +the nose, and many others. But a half sneeze does not remove the cause +of the sneeze, so it is much better to sneeze it out, and many people +enjoy the after effects of sneezing so much that they take snuff into +the nose to produce it. + + + + +What Happens When I Swallow? + + +The muscles of your throat act in the form of a ring when food passes +into your throat. The food does not drop directly into your stomach. In +other words, the action is not quite the same as when you drop a stone +out of the window. When you do the latter, the stone hits the sidewalk +or whatever is below at the time, with a smash. It would hardly do to +have our food drop into the stomach, so the muscles of the throat are +arranged to contract in rings which push or squeeze the food downward, +and the food is passed from one ring of muscles to the other. It is +just like pushing a ball down into the foot of a stocking that is +apparently too small for it to drop down. You put the ball in the top +of the stocking and then by making a ring of your fingers around the +stocking you can push the ball down. When you swallow, you start the +muscles of your throat to making these rings. The upper ring squeezes +the food on to the ring below it and so on down to the stomach. + + + + +What Makes the Lump Come In My Throat When I Cry? + + +The “lump” which comes up into your throat when you cry is caused +by a sort of paralysis of the rings of muscles in your throat. The +muscles of your throat can make these rings or waves upward also, but +it is more difficult upward than downward--probably because of lack +of practice, as we say. When you have put something into your stomach +that makes you sick and causes you to vomit, the throat muscles take +the matter from your stomach and bring it back to the mouth in the same +way, except, of course, that this action begins at the bottom. + +Sometimes when you cry, or lose control of yourself in some other +way (you know, of course, that in crying you always lose control of +yourself, don’t you) practically the same effect is produced as when +you have something in your stomach that should come out. Crying, or the +thing that happens sometimes when we cry, makes the throat muscles act +just as if we were vomiting, and as the action is an unnatural one, +when the ring or wave reaches the top of the throat, we feel the lump +or ball as we call it. We feel the lump because the throat has been +made to go through the motion of eliminating something in an unnatural +way, just as your arm will hurt if you pretend to have a ball or a +stone in it, and in throwing the imaginary ball or stone, you put the +same force into your movements as you would if you had an actual ball +or stone in your hand and were seeing how far you could throw it. + + + + +Why Do We Stop Growing? + + +We eventually stop growing because certain of the cells of the body +lose their ability of increasing in size and producing other cells. It +is one of the marvels of the construction of the human body that this +is so and one of the wisest provisions also. At first the cells of the +body crave lots of food and increase in size, divide and then the parts +go on growing until they become of a certain size, when they again +divide and each part goes on growing, etc., and thus we grow. A growing +boy needs more fond than a mature man, because he needs some of it to +grow with, while the man only has to keep what growth he has going, i. +e., alive. + +We say this limit of growth is a wise provision of nature because if +there were no limit to the size we might become, we would not know how +large to build houses, barns, etc., or else we would have to build them +so large to start with that we would be lost in them for a long time. +We would constantly be forced to change these things and there would +be no basis to reckon from. Dogs might be as big as elephants and then +they would be of no use to us, or of what use would a dog as big as an +elephant be to a boy of five years. You see it would not do at all to +have this rule changed. + + + + +Why Do We Grow Aged? + + +We age directly in accordance with the lives we lead. You can bend +a wire back and forth a number of times at the same point without +breaking it, but eventually it will break. Just so with the human body. +You can use each part of it for its own purposes a number of times, but +eventually the break will come. Or, you can fail to make a part of it +perform its regular functions, and it will die--the break will come. +The human body is the most wonderful machine in the world, but even it +will eventually wear out. Every time you move your arm, leg or some +other part of your body, you destroy some tissues. The body replenishes +and builds up those tissues again for a certain time. When you bend a +joint in your body, the body oils the joint naturally, but as you grow +older, or rather, as you use the different parts of your body more and +more, it brings nearer always the time, when the body cannot, of its +own accord, build up again the tissues you have destroyed. That is why +some people become very old at forty and others are still comparatively +young at seventy. It requires a great deal of care and attention and +the elimination of all abuse of the body to keep us young when we +are old. The use of drink, lack of sufficient sleep and other abuses +prevent the body from restoring the tissues which have been destroyed. +Worry and sorrow age us very rapidly, because these things affect the +nerves. If the nerves are not quiet we cannot get any rest and without +rest we grow old very rapidly. + + + + +What Causes Wrinkles? + + +Wrinkles come to us in several ways. An easy way to cause wrinkles is +to scowl and frown and get into the habit of doing this. When you scowl +or frown you pucker up the skin on your forehead into wrinkles and if +you continue the habit the skin on your forehead makes the wrinkles +permanent. You have given your skin the wrinkle habit. This acts just +the same way as your arm would, if you tied it up in a sling and held +it close to your side for a very long time--a number of weeks. When you +took the sling off you would find your arm useless--a dead arm. It had +developed the habit of doing nothing. + +In old people, however, wrinkles come more naturally. There it is the +case of the skin not receiving the proper nourishment and attention to +keep the circulation of the blood right. When people become old they +are apt to lose the fat which has accumulated under their skins. If +they had taken just the right amount of exercise all of their lives and +kept their circulation perfect in all parts of the body, there would +have been no fat there. But when the fat accumulates, it makes the +skin grow larger, and then when the fat disappears and people get thin +again, the skin is too large and makes the wrinkles. + + + + +Does Thunder Sour Milk? + + +Milk will sour in any kind of warm and moist temperature and, because +just before and during a thunderstorm the air is generally quite warm +and moist, it is only natural that it should turn sour. It is wrong, +however, to say or think that thunder makes milk sour. Thunder is only +a noise and noise cannot do anything but make itself heard. The fact +that it is generally warm and moist, however, when it thunders, coupled +with the fact that these conditions of the air sour milk very rapidly, +have led people to connect the two in their minds and caused them to +fall into the error of believing that the thunder is responsible for +the change in the milk. + + + + +What Makes the Rings in the Water When I Throw a Stone Into It? + + +Every movement has a beginning. When a movement on the earth is once +started it keeps on going until something stops it. If nothing stops it +it will go on forever. + +When you shout you start air waves going in every direction, which +keeps on going until stopped by something which has the power to break +up their waves. + +When you throw a stone into the ocean you start a series of ripples +or waves which spread out in every direction and if you dropped your +stone into the exact middle of the ocean--half way from each side--in +a perfectly calm sea undisturbed by other forces, your ring of ripples +would go on getting larger until it landed on the beach or shore on +each side of the ocean at the exactly the same time and there the beach +or shore would stop it. + +The original ring of ripples is caused by the fact that when you drop +a stone into the water it disturbs the water where it goes in and +the water moves away from the stone to the sides, and as the stone +goes down, over and up above it, and the whole body of the water is +disturbed in such a way that makes the ripple appear on the surface and +spread out in every direction. As the stone goes down into the water +further and further the disturbance is repeated and ring after ring +appears on the surface. + +Of course there are many disturbances in the water at all times. Many +things may happen to break up your little ring of ripples before they +touch the sides of the ocean--a ship--a fish--the wind--or one of many +other things, and because this is true you would have difficulty in +sending the waves made by your little pebble across the ocean, but you +can take a dishpan from the kitchen and after filling it with water +drop pebbles into it as nearly the middle as possible, and you will see +the ripples or waves your pebble makes spread out from the point where +the pebble entered the water in all directions. + + + + +Why Are There Many Languages? + + +Different languages developed in different parts of the world +because there was no inter-communication between people in different +communities, and each was really developing a language for itself. +In doing so they developed their language without knowing that other +communities were working out the same problems for themselves. So +they first developed their own sign and gesture language and later +on their word or sound language and kept on using it. While they may +thus have developed the use of some of the same signs and sounds or +combination of sounds to express one thing perfectly understandable to +themselves, these sounds or combinations of sounds might mean something +entirely different to another community, where that particular sound or +combination of sounds may have been hit upon to mean something entirely +different. + +Of course, not all languages were developed in this way. There are, +you know, a great many languages used in the world. Some of them are +offshoots of others, where part of a community moved to another part of +the world, taking their language with them, but developing it further +along new lines, and using new combinations of sounds for new words. +Then also, there are many words which mean the same thing in different +languages and are spoken with practically the same sounds. This is due +to the movement of people from one nation to another and bringing their +own words with them, so to speak. In many instances a stranger would +come to another nation, and use his own word for expressing a certain +thing and that would eventually be taken up and used as a better word, +and the old word dropped. It is strange that this should be true, but +this accounts for the fact that many words are the same in sound and +meaning in numerous languages. + + + + +What Makes a Match Light When We Strike It? + + +The match lights when we rub it along a rough substance, because the +rubbing produces sufficient heat on the end of the match to set fire +to the head, as we call it, which is made of chemicals that light more +easily than the stick of wood, which is the rest of the match. The fire +thus started is hot enough and burns long enough to set fire to the +wooden part of the match. + +To explain this more fully, let me say this. Rub your finger quickly +along your coat sleeve or along the seat of your trousers, long a +favorite place for men to strike matches, pretending that your finger +is a match. You find the end of your finger becomes warm, don’t you? +Not warm enough to set your finger on fire, of course, but if you had +the same combination of chemicals on the end of your finger that there +is on the match, you would set the chemicals afire and this would burn +your finger, just as it sets fire to the wooden part of the match. + +It took a great many years to discover the combination of chemicals of +which the head of the match is made. Before that discovery was made it +was far from easy to light the light in the evening as it is now. It +must have been a serious thing to let the fire go out in the furnace in +those days. + + + + +What Makes the Kettle Whistle? + + +The kettle whistles only when the water boils and the steam or gas +which is the form the water turns into when boiling is trying to +escape through the spout of the kettle. You see, when the water starts +boiling, the inside of the kettle is at once filled with steam and more +is coming out of the water all the time. This steam must get out some +way, so it rushes for the spout of the kettle, and because so much of +it is trying to get out of a comparatively small opening at once there +is quite a pressure and this results in making the whistle out of the +spout of the kettle. It is just the same process as when you whistle +yourself. To whistle you fill your mouth with air and force it out +through your lips, which you have closed excepting for a small opening, +by the pressure you can bring to bear with the roof and sides of your +mouth, and if you have learned to make your lips into the proper shape +and apply the pressure steadily you can sound a very long note and make +different notes by making the opening in your lips large or small. The +kettle spout has only one size of opening so the sound is practically +the same at all times though louder at sometimes than at others. This +is caused by the varying pressure at which the steam in the kettle is +being forced out. + + + + +What Makes the Water From a Fountain Shoot Into the Air? + + +The water from the fountain shoots into the air because water anywhere +will run down if given a chance. To produce a fountain you must have +a source of water supply for the fountain which is higher than the +openings of the fountain out of which the water shoots. The water comes +out of the holes in the fountain for the same reason that it comes out +of the faucet in the kitchen or bath room. In the latter case the water +comes from the waterworks reservoir in which the level of the water is +much higher than the opening in the faucet in your home. Being higher +the water in the reservoir is trying to get away through the pipes all +the time and all the pipes leading from the reservoir are full of this +water trying to get away. Just as soon as you turn the valve in the +faucet the water comes out and runs down into the bowl. + +If you were to turn the opening of the faucet up instead of down as +it is, the water would shoot up instead of down. Not very much, it +is true, but it would act much like the water from the fountain. The +reason it does not shoot up high in the air like a fountain is because +the opening in the faucet is the same size as the opening in the +little pipe which leads the water from the street into the house. If +you would turn the opening of the faucet up and attach to it a pipe +which made the opening much smaller (the size of the opening in the +fountains), you would see the water shoot into the air just as it does +from the fountain. When you reduce the size of the opening you increase +the pressure of the water coming from the pipes in proportion to the +reduction you have made in the size of the opening. + +Water from the fountain will not, however, shoot as high as the level +of the water in the reservoir because, as soon as it leaves the pipes, +it encounters the pressure of the air outside the pipes and the law of +gravitation which pulls all things toward the center of the earth. + +It is not natural for water to shoot into the air as it does in a +fountain. The only way water can go naturally is down, and it only goes +up a little way from a fountain because of the pressure of the water in +the pipes behind the openings in the pipes in the fountain. + + + + +What Keeps a Balloon Up? + + +A balloon stays up in the air, because of the air in it, together with +the weight of the balloon, is less than an equal bulk of the air in +which it floats. + +In former days of ballooning the balloons were filled with hot air and +were then found to rise and stay up until the air inside of the balloon +became of the same temperature as that in which it floated. When this +stage was reached, the balloon itself would fall because the material +of which it was made was denser than air. + +Today balloonists fill their balloons with gas which is lighter than +air, even when as cool as the air in which they rise and are thus able +to stay up a long time. + +You, of course, have seen many of the red, white and blue paper +balloons which are sent up on the Fourth of July. You will remember +that father, or whoever it is that is sending them up, lights the +oil-soaked knot of cloth that is attached to the balloon immediately +below the opening at the bottom. He first lights this and then holds +the balloon for a time with his hands. + +Soon, however, you will remember that the balloon starts upward with +father still holding it. This is because the air inside the balloon +is becoming heated. You will notice also that at first he has to hold +out the sides of the top of the balloon with his hands or has some +one help him do this, but that even so the balloon does not stand out +round and full as it should. When the balloon starts to rise, however, +you will notice that it is round and full. This is because the air in +the balloon has become heated and is expanding. Soon the balloon is +tugging to get away and father lets go and it rises and sails away with +the wind. As long as the fire below it burns, and if the wind does not +upset it so as to make the paper part catch fire, the balloon will stay +up; but, when the fire burns out, the balloon will come down. + +The balloon merely rises because the air inside, and held there by the +covering of the balloon, is warmer air and lighter than the air on the +outside. + + + + +Why Did People of Long Ago Live Longer Than We Do Now? + + +When reading of people who lived long years ago and especially when +reading about the length of their lives, we are told that in the old +days people lived longer than they do now. Some of the early historical +records speak of single individuals who lived hundreds of years. There +is great doubt as to whether these statements are founded on fact. In +thinking about this we must first take into consideration that these +records of long ages were recorded at a time when man had no accurate +ideas of the actual passage of long periods of time such as a year. +They did not have our calendar as a basis for figuring at all. Learned +men now tell us that the actual age of men who lived at the time these +records of great ages were recorded probably lived shorter lives +than we do now, and that what they record as a period of one year was +probably a much shorter period than one year. + +It is true beyond the question of a doubt that the people of today live +longer on the average than people who lived ten, twenty or more years +ago. + +In other words, the average period of life has increased steadily. +This is due to the fact that we have taken great care of our bodies; +have improved the conditions in which we live, and made them more +sanitary; have learned to fight and check and eradicate diseases, which +only a few years ago we could not prevent people dying of when they +once contracted them, and we know from the records which we keep that +actually people live longer on the average today than only a few years +ago, and it is safe to say that they live longer now on the average +than at any time in the world’s history. + + + + +Is There a Reason for Everything? + + +The world is so constructed that there must be a reason or cause for +everything. There are so many forces in the world that man has not yet +been able to locate the original cause of every one of them. Concerning +other things, he sees the effects without having any knowledge of the +forces which are their cause. Other things he has never even bothered +to inquire about, but simply takes them for granted. But every force, +which means, of course, everything in the world, must have had a +beginning and therefore something or a combination of things must have +caused it to begin, and the thing or things that caused it to be is the +reason for its being. Every little while someone makes a discovery of +some new force, and then we suddenly realize that this force has been +in existence all the time although not known to man, and we discover +through this the reason for many other things being as they are. + +The other thing or side of the question is also true. We cannot have +a cause without an effect. You cannot do anything without causing +something to happen and producing an effect on one or more other +objects either animate or inanimate. You cannot move your hand without +creating some disturbance in the air. When you make a noise, low or +loud, you produce sound waves. When you burn a stick of wood, you +create smoke, ashes and gases of various kinds. You change the whole +nature of what was the piece of wood, and yet no particle of what made +the stick of wood is ever destroyed or lost, but appears in some other +thing in the air or on or in the earth. + + + + +What Makes an Echo? + + +An echo is caused when the waves of air which you create when you shout +are thrown back again when they are stopped by something they encounter +and are turned back without changing their shape. Any kind of a sound +wave will make an echo in this way. + +You see, you can have no sound of any kind without sound waves. You +could not make a sound if there were no air. Now, when you shout, you +start a series of sound waves that go out from you in every direction +and they spread away from you in circles just like the rings of ripples +that are caused when you drop a stone into a pool of water. You can +prove this to yourself easily by having one, two, three or more of your +friends stand around you in a large circle. You can place them as far +away from you as your shout can be heard if you wish. When you shout, +each of your friends will hear the shout at the same time, provided, of +course, they are at equal distances from you. + +Sometimes these sound waves as they go away from you in circles strike +objects that turn the waves back unbroken just as they came to them. +The waves will bounce back just like a rubber ball from a wall against +which it has been thrown and this is the echo. However, some things +that the sound waves strike break up these waves entirely and others +partially. + +No doubt you have sometimes noticed when you shout you hear a distinct +echo and that at other times, standing in the same place, you cannot +hear any echo, although you shout in the same way. This is explained by +the fact that at times conditions of the air are such that no echo is +produced while at other times a perfect echo results. + + + + +What is a Whispering Gallery? + + +The possibilities of an echo have to be taken into account by the +architects and builders of all public buildings, such as theaters, +halls and churches, where anyone is to speak or entertain others. +Unless they are very careful the walls and ceilings may be so arranged +that when any one sings or speaks in the room, there is such an echo +that it interferes with the music or speaking. It sometimes happens +also that through some peculiarity in which the walls and ceiling of +a building are constructed there will be certain places in the room +where an echo can be heard, even a whisper, and which cannot be heard +in other parts of the room at all. This is likely to occur in rooms +where there is a dome-shaped ceiling. There will be certain spots in +the room hundreds of feet apart, where if you stand on one spot and +another person is on another definite spot clear across the room, the +tiniest whisper can be heard, while the people in between cannot hear +at all. This is called a whispering gallery. Of course, loud talking +would produce the same effect. A whispering gallery is a gallery with +an echo which can be heard from certain positions. There are a number +of famous whispering galleries of the world. In the room beneath the +great dome of our Capitol at Washington is an almost perfect whispering +gallery. There are quite a number of points at which you can stand and +hear the whispers across the room which is more than a hundred feet. +These whispering galleries come accidentally, of course. It would be +difficult to deliberately construct a building in such a way as to +produce a whispering gallery. + + + + +Why Do We Get a Bump Instead of a Dent When We Knock Our Heads? + + +When you knock your head against a sharp corner, or if some one hits +you on the head with anything with a sharp edge, you do receive a dent +in your head, but it does not last. In other words, the head has one of +the qualities of a rubber ball. You can press your finger against the +sides of the rubber ball and push it in, but when you take your finger +off the ball resumes its shape. Just so with your head--it resumes its +shape after a blow. + +After doing this, however, a bump or lump is formed. I will endeavor to +tell you how the bump is formed or rather what causes it to form. You +cannot knock your head against anything that is harder than your head +without causing some injury to the parts which received the bump. Now, +what happens then is just what happens to any other part of your body +when it is injured whether as a result of a bump, a cut or a bee or +mosquito sting. + +As soon as the injury occurs the brain starts the “repair crew” to +work. The result is that first a great supply of blood is rushed to the +injured part with the result that the blood vessels are filled up and +extended with blood. Certain parts of the blood cells find their way +through the walls of the blood vessels at the part of the injury and +other fluids from the body are piled up there, so to speak, to form a +congestion. This “piling up or congestion” distends the skin and raises +the bump. On the head where the layer of muscular structure is thinner +and where there is less space between the bones of the skull and the +outside skin, the bump will be larger and more noticeable, because a +good deal of blood and other fluids are piled up in a comparatively +small space, and so the skin gets pushed out further to accommodate +this great congestion, whereas in other parts of the body the bump may +be quite as large but not so noticeable. + +[Illustration: HOW MEN GO DOWN TO THE BOTTOM OF THE SEA + +PUTTING ON THE SUIT. + +Socks, trousers and shirt in one, and a copper breastplate.] + +[Illustration: PUTTING ON THE IRON-SOLED SHOES. + +They are purposely made heavy, to help the diver sink.] + + + + +The Deep Sea Diver + + +What Does the Bottom of the Sea Look Like? + +It looks very much like the land on which we live. There are mountains +and valleys, rocks and crags, trees and grass, just the same as we see +on land, except, of course, that there are no human beings to be seen. +Instead of birds flitting about the tree-tops, fish swim about them, +and where the squirrel and rabbit bound through the woods on land, the +great king crab and sea turtle drag their unwieldy forms on the ocean’s +bottom. Some of the scenes at the bottom of the sea are like fairyland, +and in tropical waters are often as beautiful and spectacular as those +we see in theatrical pantomimes. Delicately tinted sea-shells, great +trees of snow-white coral, sea foliage of every tint and shape, and +deep dark caverns, in which lurk the devil-fish and other odd looking +fish. + + +The Diver’s Outfit. + +The armor of to-day consists of a rubber and canvas suit, socks, +trousers and shirt in one, a copper breastplate or collar, a copper +helmet, iron-soled shoes, and a belt of leaden weights to sink the +diver. + +[Illustration: ADJUSTING THE TELEPHONE. + +This enables the diver to talk at all times to those above him.] + +[Illustration: PUTTING ON THE HELMET. + +It is made of tinned copper, with three glass-covered openings, to +enable the diver to look out.] + +[Illustration: TELEPHONING FROM THE BOTTOM OF THE OCEAN + +TESTING THE TELEPHONE. + +Every precaution is taken to see that everything is in order before the +diver goes down.] + +[Illustration: THE FINAL TEST. + +The least error in the adjustment may mean death to the diver.] + +The helmet is made of tinned copper, with three circular glasses, one +in front and one on either side, with guards to protect them. The +front eye-piece is made to unscrew and enable the diver to receive +or give instructions without removing the helmet. One or more outlet +valves are placed at the back or side of the helmet to allow the +vitiated air to escape. These valves only open outwards by working +against a spiral spring, so that no water can enter. The inlet valve +is at the back of the helmet, and the air on entry is directed by +three channels running along the top of the helmet to points above the +eye-pieces, enabling the diver to always inhale fresh air. The helmet +is secured to the breastplate below by a segmental screw-bayonet joint, +securing attachment by one-eighth of a turn. The junction between the +water-proof dress and the breastplate is made watertight by means of +studs, brass plates and wing-nuts. + +A life or signal-line and also a modern telephone enables the diver to +communicate at all times with those above him. + +The cost of a complete diving outfit ranges from $750.00 to $1,000.00. +The weight of the armor and attachments worn by the diver is 256 +pounds, divided as follows: Helmet and breastplate, 58 pounds; belt of +lead weights, 122 pounds; rubber suit, 19 pounds; iron-soled shoes, 27 +pounds each. + +The air which sustains the diver’s life below the surface is pumped +from above by a powerful pump, which must be kept constantly at work +while the diver is down. A stoppage of the pump a single instant while +the diver is in deep water would result almost in his instant death +from the pressure of the water outside. + +The greatest depth reached by any diver was 204 feet, at which depth +there was a pressure of 88¹⁄₂ pounds per square inch on his body. The +area exposed of the average diver in armor is 720 inches, which would +have made the diver at that depth sustain a pressure of 66,960 pounds, +or over 33 tons. + +The water pressure on a diver is as follows: + + 20 feet 8¹⁄₂ lbs. + 30 feet 12³⁄₄ lbs. + 40 feet 17¹⁄₄ lbs. + 50 feet 21³⁄₄ lbs. + 60 feet 26¹⁄₄ lbs. + 70 feet 30¹⁄₂ lbs. + 80 feet 34³⁄₄ lbs. + 90 feet 39 lbs. + 100 feet 43¹⁄₂ lbs. + 120 feet 52¹⁄₄ lbs. + 130 feet 56¹⁄₂ lbs. + 140 feet 60³⁄₄ lbs. + 150 feet 65¹⁄₄ lbs. + 160 feet 69³⁄₄ lbs. + 170 feet 74 lbs. + 180 feet 78 lbs. + 190 feet 82¹⁄₄ lbs. + 204 feet 88¹⁄₂ lbs. + +The dangers of diving are manifold, and so risky is the calling that +there are comparatively few divers in the United States. The cheapest +of them command $10.00 a day for four or five hours’ work, and many of +them get $50.00 and $60.00 for the same term of labor under water. + +The greatest danger that besets the diver is the risk he runs every +time he dives of rupturing a blood-vessel by the excessively compressed +air he is compelled to breathe. He is also subject to attacks from +sharks, sword-fish, devil-fish, and other voracious monsters of +the ocean’s depths. To defend himself against them, he carries a +double-edged knife as sharp as a razor. It is the diver’s sole weapon +of defense. + +Just how far back the art of submarine diving dates is a matter of +conjecture, but until the invention of the present armor and helmet, +in 1839, work and exploration under water was, at best, imperfect, and +could only be pursued in a very limited degree. + + +Feats of Divers. + +~THE GREATEST DIVING FEAT~ + +Millions of dollars’ worth of property has been recovered from the +ocean’s depth by divers. One of the greatest achievements in this line +was by the famous English diver, Lambert, who recovered vast treasure +from the “Alfonso XII,” a Spanish mail steamer belonging to the Lopez +Line, which sank off Point Gando, Grand Canary, in 26¹⁄₂ fathoms of +water. The salvage party was dispatched by the underwriters in May, +1885, the vessel having £100,000 in specie on board. For nearly six +months the operations were persevered in before the divers could reach +the treasure-room beneath the three decks. Two divers lost their lives +in the vain attempt, the pressure of water being fatal. The diver +recovered £90,000 from the wreck, and got £4,500 for doing it. + +One of the most difficult operations ever performed by a diver was the +recovering of the treasure sunk in the steamship “Malabar,” off Galle. +On this occasion the large iron plates, half an inch thick, had to be +cut away from the mail-room, and then the diver had to work through +nine feet of sand. The whole of the specie on board this vessel--upward +of $1,500,000--was saved, as much as $80,000 having been gotten out in +one day. + +It is an interesting fact that from time to time expeditions have been +fitted out, and companies formed, with the sole intention of searching +for buried treasure beneath the sea. Again and again have expeditions +left New York or San Francisco in the certainty of recovering tons of +bullion sunk off the Brazilian coast, or lying undisturbed in the mud +of the Rio de la Plata. + +[Illustration: The last look just before going down.] + +[Illustration: Coming up after a successful trip.] + +At the end of 1885, the large steamer Imbus, belonging to the P. & O. +Co., sank off Trincomalee, having on board a very valuable East-India +cargo, together with a large amount of specie. This was another case +of a fortune found in the sea, for a very large amount of treasure was +recovered. + +Another wreck from which a large sum of gold coin and bullion was +recovered by divers, was that of the French ship “L’Orient.” She +is stated to have had on board specie to the value of no less than +$3,000,000, besides other treasure. + +A parallel case to “L’Orient” is that of the “Lutine,” a warship of +thirty-two guns, wrecked off the coast of Holland. This vessel sailed +from the Yarmouth Roads with an immense quantity of treasure for the +Texel. In the course of the day it came on to blow a heavy gale; the +vessel was lost and went to pieces. Salvage operations by divers, +during eighteen months, resulted in the recovery of £400,000 in specie. + +Humorous scenes do not play much of a part on the ocean’s bottom, and +the sublime and awe-inspiring are far more in evidence there than the +ludicrous, yet even beneath the waves there are laughable scenes at +times. A diver had been engaged to inspect a sunken vessel off the +coast of Cuba. Arriving on the scene he discovered a number of native +sponge-divers, who descend to considerable depths, diving down from +their canoes to the sunken vessel trying to pick up something of value. +They paid little attention to the arrival of the wrecking outfit, and +did not notice the diver descend, until suddenly what seemed to them to +be a horrible human-shaped monster, with an immense head of glistening +copper and three big, round, glassy eyes, came walking around the +vessel’s bow and made a big salaam to them. That was enough. They shot +surfaceward like sky-rockets, climbed frantically into their canoes and +hurriedly rowed away. + + + + +What Happens When Anything Explodes? + + +By explosives are meant substances that can be made to give off a large +quantity of gas in an exceedingly short time, and the shorter the time +required for the production of the gas the greater will be the violence +of the explosion. Many substances that ordinarily have no explosive +qualities may be made to act as explosives under certain circumstances. +Water, for example, has caused very destructive boiler explosions when +a quantity of it has been allowed to enter an empty boiler that had +become red hot. Particles of dust in the air have occasioned explosions +in saw mills, where the air always contains large quantities of dust. +A flame introduced into air that is heavily laden with dust may cause +a sudden burning of the particles near it, and from these the fire may +be conveyed so rapidly to the others that the heat will cause the air +to expand suddenly, and this, together with the formation of gases from +the burning, will cause an explosion. + +It must not be thought, however, that fine sawdust or water would +ordinarily be classed as explosives. The term is generally applied only +to those substances that may be very easily caused to explode. + +The oldest, and most widely known, explosive that we possess is +gunpowder, the invention of which is generally credited to the Chinese. +It is a mixture of potassium nitrate, or saltpeter, with powdered +charcoal and sulphur. The proportions in which these substances are +mixed vary in different kinds of powder, but they usually do not differ +much from the following: + + Sulphur 10 per cent. + Charcoal 16 per cent. + Saltpeter 74 per cent. + +The explosive quality of gunpowder is due to the fact that it will burn +with great rapidity without contact with the air, and that in burning +it liberates large volumes of gas. When a spark is introduced into it, +the carbon, charcoal, and sulphur combine with a portion of the oxygen +contained in the saltpeter to form carbonic acid gas and sulphurous +acid gas, and at the same time the nitrogen contained in the saltpeter +is set free in the gaseous form. This action takes place very suddenly, +and the volume of gas set free is so much greater than that of the +powder that an explosion follows. + +In the manufacture of gunpowder all that is absolutely necessary is to +mix the three ingredients thoroughly and in the proper proportions. +But to fit the powder for use in firing small arms and cannon it is +made into grains of various sizes, the small sizes being used for the +small arms with short barrels, and the large sizes for cannon. The +reason for this is that if the powder is made in very small grains it +all burns at once, and the explosion takes place so suddenly that an +exceedingly strong gun is required to withstand the explosion, while if +larger grains are employed the burning is slower and continues until +the projectile has traveled to the muzzle of the gun. In this way the +projectile is fired from the gun with as much force as if the explosion +had taken place at once, but there is less strain on the gun. + + + + +What Causes the Smoke When a Gun Goes Off? + + +Powder of this latter kind always produces a considerable quantity of +smoke when it is fired, because there is a quantity of fine particles +formed from the breaking up of the saltpeter and from some of the +charcoal which is not completely burned. This smoke forms a cloud that +takes some time to clear away, which is a very objectionable feature. +In order to get rid of it, efforts were made to produce a substance +that would explode without leaving any solid residue, and that could be +used in guns. These efforts were finally successful, and there are now +several brands of smokeless powder in use. + + + + +What is Smokeless Powder Made Of? + + +The most satisfactory forms of smokeless powder are all made from +guncotton or nitrocellulose. This substance, which is made by treating +cotton with a mixture of nitric and sulphuric acids, is a chemical +compound, not a mixture like gunpowder; and when it is exploded it is +all converted into gases, of which the chief ones are carbonic acid +gas, nitrogen, and water-vapor. To cause the explosion of guncotton it +is not necessary to burn it, but a mere shock or jar will cause it to +decompose with explosive violence. Of course, such a violent explosive +as this could not be used either in small arms or in cannon, but +guncotton can be converted into less explosive forms which are suitable +for use in guns, and the majority, of smokeless powders are made in +this way. The methods used in producing the smokeless powders are kept +secret by the various countries that use them. + + + + +What is Nitroglycerine? + + +Another very powerful explosive, which is closely related to guncotton, +is nitroglycerine. This compound is made by treating glycerine with the +same sort of acid mixture that is used in making guncotton. It explodes +in the same way that guncotton does and yields the same products. It is +an oily liquid of yellow color, and on account of its liquid form it is +difficult to handle and use. The difficulty in handling nitroglycerine +led to the plan of mixing it with a quantity of very fine sand called +infusorial earth. When mixed with this a solid mass called dynamite is +formed, which is easier to handle and more difficult to explode, but +which has almost as much explosive force as nitroglycerine. + +A more powerful explosive than either nitroglycerine or guncotton is +obtained by mixing them together. When this is done the guncotton +swells up by absorbing the nitroglycerine and becomes a brownish, +jelly-like substance that is known as blasting gelatin. This is +generally considered the most powerful explosive obtainable. + + + + +What Makes Nitroglycerine and Guncotton Explode So Readily? + + +Let us now consider for the moment what it is that makes guncotton, +nitroglycerine, and blasting gelatin explode so readily. The +explanation is found in the presence in them of nitrogen. As you +remember from what you learned about air, nitrogen is an extremely +inactive element. It has no strong tendency to combine with other +elements, and when it does enter into combination with them the +compounds formed are almost always easily decomposed. In the compounds +that have just been described a shock causes a loosening of the bonds +that hold the nitrogen, and the whole compound goes to pieces just as +an arch falls when the keystone is removed. + + + + +What Is Silver? + + +Since the earliest time recorded in history, silver has been the +most used of the precious metals, both in the arts and as a medium +of exchange. Even in the prehistoric times silver mines were worked +and the metal was employed in the ornamental and useful arts. It was +not so early used as money, and when it began to be adopted for this +purpose, it was made into bars or rings and sold by weight. The first +regular coinage of either gold or silver was in Phrygia, or Lydia, +in Asia Minor. Silver was used in the arts by the Athenians, the +Phœnicians, the Vikings, the Aztecs, the Peruvians, and in fact by all +the civilized and semi-civilized nations of antiquity. It is found +in almost every part of the globe, usually in combination with other +metals. The mines in South America, Mexico, and the United States are +especially rich. Silver is sometimes found in huge nuggets. A mass +weighing 800 pounds was found in Peru, and it is claimed that one of +2,700 pounds was extracted in Mexico. The ratio of the value of silver +and gold has varied greatly. At the Christian era it was 9 to 1; 500 +A.D. it was 18 to 1; but in 1100 A.D. it was only 8 to 1. In 1893 +it was as high as 2,577 to 1. The subject has entered largely into +American politics as a disturbing element, and in 1896 the Democratic +party, in its national convention, declared for the free coinage of the +metals at 16 to 1. The Republican party adhered to the gold standard +and declared against the free coinage of silver. Each party reaffirmed +in 1900 this plank in its platform. In both years the Democrats were +defeated. + + + + +What Is Worry? + + +Worry is a feeling of fear, but is never of the present. It is always +about something that may happen or that has happened. It is generally +in the future, sometimes in the past, but never in the present. + +An animal that knows neither future nor past cannot worry. Babies, +living only as they do in the present, cannot worry. All creatures, +excepting human beings, live only in the present and therefore they do +not worry, for such creatures cannot remember what happened in the past +or guess what is going to happen. + +A human being after arriving at a certain age is given such powers +that his mind can go back to the past and cast itself forward into the +future as he thinks it will be, because he has imagination. As a matter +of fact we live less in the present than in the past or future. + + + + +Why Do We Worry? + + +We worry because we are able through a power called self-consciousness +to place ourselves through our minds for the time being. Either--back +somewhere in the past without carrying our physical bodies with us; for +if we could take our bodies with us, we would be in the present again, +and then worry is impossible; or, we use our imagination and project +the future entirely apart from our bodies, for we cannot project our +bodies into the future, and if we could we would again be in the +present. We worry over going to have an operation performed which may +or not be dangerous, but quite necessary. We may still think we worry +when the operation begins, but as soon as that occurs the time becomes +the present, and though we may fear, we cannot worry in the present. + +[Illustration: + + _Back View of Shield_ + + _Longitudinal Section through Shield & Tunnel_ + + _Diagram showing method of tunnel construction by shield and + compressed air._ + + _Scale; ¹⁄₈ inch · 1 foot_ + + _Jacobs & Davies Inc. 30 Church St. N.Y._ + + _Oct. 15. 1910._ + +FIGURE 1.] + + + + +The Story in a Tunnel + + +How a Tunnel Is Dug Under Water. + +Fig. 1. On the left is a cross section showing, in diagram, the back +view of a shield. The heavy black circle is the “tail” or “skin.” +The small circles within the tail are the hydraulic rams which at a +pressure of 5,000 pounds to the square inch force the shield forward. +The square compartments within the shield are the openings through +which the men pass to dig away the ground. In the middle of the shield +is shown the swinging “erector” which picks up the iron lining plates +and puts them in position. + +The view on the right is a longitudinal section of the tunnel showing +the shield and the bulkhead wall across the tunnel with the air locks +built into it. The front of the shield ahead of the doors is made with +a sharp edge called the “cutting edge” and this makes it easier for the +shield to advance in case all the ground in front has not been removed. +This view shows how the tail overlaps the last portion of the iron +lining. + +Some distance behind the shield comes the concrete bulkhead wall with +the air locks contained in it. There are two shown in the view. The +upper one is the emergency air lock, always kept ready so that in case +of an accident the men have a means of escape even though the lower +part of the tunnel is filled with rushing water or mud. The lower air +lock is for the passage of men and materials during ordinary working. +This view also shows that all the tunnel ahead of the bulkhead wall +is under compressed air while the finished tunnel behind the bulkhead +wall is under the ordinary or normal air pressure. When the tunnel is +finished the air locks and bulkhead walls are removed. + +[Illustration: FRONT VIEW OF A DRIVING SHIELD + +This shows the front of one of the shields used on the Pennsylvania +Railroad tunnels crossing the North River at New York. The cutting edge +is clearly seen and the various compartments, each with its door, which +divide up the front of the shield. These shields weighed about 200 tons +each.] + + +HOW TUNNELS ARE BUILT. + +These notes describe very generally the way in which tunnels are built +through mud and gravel under parts of the sea or large rivers in such +a way that the men who build them are protected and as safe as the +carpenter who is building a house. + +The way these tunnels are built is called the “shield” way because +the machine used is called a shield. It is given this name because it +shields the tunnel builders from the water and the mud which are ready +at every moment to overwhelm them and kill them. + +The shield was invented in 1818 by a great Engineer, Marc Isambard +Brunel, who was a Frenchman living in England. The idea of the shield +came to him as he saw how the sea worm which attacks the wooden piles +of docks along the shore bores the holes it makes in the wood. The head +of this worm is very hard and can bite its way through the hardest +woods. As it goes through the wood its body makes a hard shelly coating +which lines the holes which its head has made and prevents the hole +from getting filled up. This is the general idea of a tunnel built by a +shield. + +The first shield was used by Mr. Brunel to make a tunnel across the +Thames River at London, England. This is still the biggest tunnel +ever built by a shield, although not the longest, and is still +used by railroad trains. This tunnel was begun in 1825 and was +finished in 1843, and provides a history of almost unexampled and +not-to-be-excelled courage in attacking difficulties and skill in +defeating them. + +Since the days of Brunel many great improvements have been made in the +shield and in the way of working it but the same idea is still there. + +[Illustration: HOW THE SHIELD IS PUSHED FORWARD + +This shows the rear end or tail end of one of the smaller shields, used +on the Hudson and Manhattan Railroad tunnels under the North or Hudson +River at New York. It shows the skin, the hydraulic jacks within the +skin and the piping and valves for working them. It also shows the +doors leading to the front or “face.” The erector is not shown, but the +circular hole in the middle shows where it would be attached.] + +[Illustration: This shows one side of an air lock bulkhead wall with +the air lock in place. The boiler-like appearance of the lock is +clearly visible, as well as the door and the pressure gauge to tell the +air pressure inside the lock.] + +[Illustration: This is a rear view of one of the Pennsylvania Tunnel +shields, taken after a length of tunnel had been completed. All the +details of construction are shown, but in this case the erector is +clearly seen also. The valves which control the erector and the rams +which push the shield forward are seen near the top of the shield. The +rods across the tunnel are turn-buckles used to keep the iron lining +from getting out of shape in the soft mud. These are removed later. The +floor and tracks in the bottom are temporary and are used for bringing +materials to and from the shield.] + +After the days of Brunel’s shield another great help was given to +tunnel builders by the invention of the use of compressed air to hold +back the water which saturates the ground in which the tunnel is being +built. + +~WHO INVENTED THE COMPRESSED AIR METHOD~ + +The first real invention of compressed air for this purpose was made +by Admiral Sir Thomas Cochrane who, in 1830, took out a patent for the +use of compressed air to expel the water from the ground in shafts and +tunnels and, by this means, to convert the ground from a condition of +quicksand to one of firmness. This patent covers all the essential +features of compressed air working. + +As suggested above, the thing which compressed air does in a tunnel +is to push the water out from all the spaces which it fills in the +ground, so that the men who are digging away the ground for the tunnel +are working in firm dry ground instead of a mixture of earth and water +which will run into and fill the hole they dig as soon as it is dug. + +Whenever a tunnel is being built below a body of water through ground +which is porous, or in other words through any ground except solid +rock or dense clay, the water fills every crevice and space in the +ground and is exerting a pressure of about half a pound per square inch +above the ordinary pressure of the air, (which is 15 pounds to the +square inch) for every foot of depth below the surface of the water; +so that supposing the tunnel is 40 feet below the water the water has +a pressure of nearly 20 pounds per square inch on every square inch +of the surface of the tunnel. This pressure causes the water to flow +violently into any hole or opening that is made in the ground, and, +unless the water is prevented from moving by some means or other, the +opening made would be very quickly filled with water and also with +ground as the rush of water will carry the sand, gravel or mud with it. + +By Cochrane’s invention the whole tunnel is filled with air under +a pressure equal to the pressure of the water. This compressed air +therefore balances the pressure of the water and holds it back from +moving, and if the pressure of the air is made slightly greater than +that of the water the water is driven back from the tunnels for a short +distance so that when the tunnel is being dug the ground instead of +being wet is quite dry. + +This explains the principles of the shield and compressed air way of +making a tunnel. + +The following describes very shortly how these principles are put to +actual use. + +Most tunnels which are built by shield and compressed air under rivers +or arms of the sea are lined with cast iron plates to protect the +railway or roadway which is in the tunnel. + +The tunnel is a circular tube, or shell, and the plates have flanges +on all sides which are bolted together. This shell is put into place, +plate by plate, by means of the shield which not only protects the +workmen and the work under construction, but which helps to build the +iron shell. In fact it corresponds to the sea worm which bores through +the wood and lines the hole with a shell. In the case of the tunnel +the shell is made of iron. The shield itself consists of a steel tube +or cylinder slightly bigger in diameter than the tube or tunnel it +is intended to build. The front edge of this shield is made up of a +ring of sharp edged castings which form what is called the “cutting +edge.” Just behind the cutting edge is a bulkhead or wall of steel, in +which are openings which may be opened or closed at will. Behind this +bulkhead are placed a number of hydraulic jacks or presses arranged +around the shield and within it, so that by thrusting against the last +erected ring of iron lining the whole shield is pushed forward. The +rear end of the shield is a continuation of the cylinder which forms +the front end, and this part, called the “tail,” always overlaps the +last few feet of the built up iron shell. + +[Illustration: This is a photograph of a model of the Pennsylvania +Tunnels to New York City, made for the Jamestown Tercentenary +Exposition of 1907. It is given because it illustrates, as no +photograph of actual work could do, the relationship between the +shield, the tunnel itself and the air lock. This view shows the rear +part of the shield on the extreme left, with the erector picking up an +iron plate. It shows a man bringing a car with two of the iron plates +up to the shield. Behind this man comes the bulkhead wall with the +emergency air lock in the top and the ordinary air lock for passing +in and out at the bottom. It also shows the upper platform to the +emergency lock along which the men can get to the emergency lock in +case of an accident.] + +[Illustration: This is another view of the same model, but showing the +front view of the shield. The doors on the air locks are clearly shown.] + +[Illustration: This is a photograph taken in one of the Pennsylvania +tunnels under the Hudson River. It shows the soft mud, through which +the tunnel is being built, flowing in a thick stream through one of +the doors of the shield. The mud under the Hudson, where these tunnels +are, is so soft that often the shield was pushed through the mud with +all the doors shut, so that no mud came into the tunnel and no digging +had to be done, but the shield pushed its way bodily through the mud, +the rings of iron lining being built up behind as usual. Generally, +however, a certain amount of mud was brought in and had to be removed. +This photograph shows how it looked.] + +~HOW THE SHIELD CUTS THROUGH THE GROUND~ + +The diagram, Fig. 1, shows more clearly what is meant. From an +inspection of Figure 1 it is clear that, when the openings in the +shield bulkhead are closed, the tunnel is protected from an inrush +of either water or earth; the openings in the bulkhead may be so +regulated that control is maintained over the material passed through. +After a ring of iron lining has been erected within the tail of the +shield, the shield doors are opened and men go through them and dig +out enough earth for the shield to go ahead. The rams are then thrust +out thus pushing the shield ahead. Another ring of iron is built up +within the tail for which purpose an hydraulic swinging arm, called the +“erector,” is mounted on the shield face. This erector picks up the +plates and puts them into position, one by one, while the men bolt them +together. Excavation is then carried on again and the whole round of +work repeated, gaining every time the jacks are rammed or thrust out +a length equal to the length of one ring of iron lining. In carrying +out this work in ground charged with water the shield is assisted by +introducing compressed air as described before. To use the compressed +air thick bulkhead walls of masonry are built across the tunnel behind +the shield and into the space between the shield and the bulkhead wall +air is pumped, compressed to the same pressure as that of the water in +the ground, or in other words the pressure of the air in pounds per +square inch is about half the number of feet the tunnel is below the +water surface. This dries the ground and simplifies enormously the +difficulty of working in it. The diagram, (Fig. 1) shows a bulkhead +wall across the tunnel. In order to pass from the ordinary air outside +the bulkhead into the compressed air inside it, all the men and the +materials have to pass through the “air locks” which are built into +the wall. They are called air locks because they are like the locks on +a canal which raise the water from a lower to a higher level or lower +it from a higher to a lower level as the case may be. The difference +is that an air lock enables one to pass from air at a low pressure to +one of a higher, or vice versa. An air lock is made like a large boiler +with a door at each end. If we wish to enter the compressed air we +enter the lock from the outside. The door at the end has been tightly +closed to prevent the compressed air from rushing out. We close the +door behind us and are now tightly shut in the boiler-like lock. We now +open a valve and compressed air begins to flow quickly into the air +lock and the air gets hotter and hotter, due to the compression of the +air. Very likely an intense pain begins to make itself felt in the ears +but by swallowing hard and blowing the nose it may be relieved. It is +caused by the air pressure being greater on the outside of the ear drum +than on the inside. If the delicate ear passages are choked, because +of a cold or some such reason, it is unsafe to go further or the ear +drum may burst. When the pressure in the air lock has reached that in +the working chamber, the door leading to the shield may be opened and +we can pass to the working space and note the work going on. There is +no especial bodily sensation to be felt except a slight exhilaration +and it is curious to find that one cannot whistle. On leaving the +compressed air we enter the air lock by the door we left; a valve is +turned and the air begins to escape and the pressure in the air lock +begins to go down. As it does so the air becomes colder and colder +and the whole lock is filled with a wet fog due to the chilling by +expansion of the air. The air has to be allowed to escape very slowly, +as bubbles of air and gas otherwise form in the blood vessels and +tissues of the body giving rise to the very painful complaint known to +tunnel builders as “the bends,” and in very serious cases to paralysis +and even death. The higher the air pressure the more slowly must one +come out into the ordinary air. + +[Illustration: MAKING THE JOINTS WATER TIGHT + +This shows the erector building up the iron lining in one of the +Pennsylvania tunnels at New York. It shows clearly how the iron plates +are bolted together to make the rings of iron lining.] + +[Illustration: The last, or closing, plate of each iron ring is called +the “key,” and is much shorter than the others. This photograph shows +the shield erector on one of the Pennsylvania tunnels picking up and +putting into place a key plate. This picture gives an idea of the mud +and dirt and wet in which the men who work in tunnels have to do their +work.] + +[Illustration: Wherever possible, every space and crevice outside the +iron lining is filled with cement forced, in a liquid state, through +the iron lining by compressed air. This photograph shows the operation +of “grouting,” as it is called. The man at the left is in control of +the grouting. He has the hose, through which the grout is forced, +screwed to a pipe which passes through a hole made for the purpose in +the iron lining plates and called a “grout hole.” The two men in the +middle of the picture are attending to the “grouting machine” by which +the work is done. Water and cement are fed into the small boiler-like +tank, the tank closed and compressed air admitted thus blowing the +liquid cement through the hose and behind the iron lining. When no +more grout can be forced behind the iron lining all the space has been +filled. The man on the right is the engineers’ inspector taking note of +how much grouting is done, and seeing that the work is properly carried +out.] + +[Illustration: This shows the process by which the iron lining is made +perfectly water-tight, so that, when the compressed air is taken off, +no water at all can get into the tunnel. Two operations are shown here. +One is called “grommetting the bolts,” the other is called “caulking +the joints.” The two men on the left, hanging on to the wrench, are +tightening up the bolts as tight as they can after having put on, +underneath the washers at the head and nut of each bolt, a ring of +spun yarn dipped in red lead and oil or tar or some such water-proof +material. A few of these “grommets” may be seen at the feet of the +third man from the left. The other four men are caulking the joints +between the iron plates by driving into the joints a mixture of sal +ammoniac and iron borings. This sets as hard as iron and if properly +done makes a perfectly water-tight joint.] + +[Illustration: THE REMARKABLE ACCURACY OF ENGINEERING + +Usually when crossing, with a tunnel, a wide river or estuary the +tunnel is started from each shore and the shields are pushed through +the ground until they meet somewhere about the middle of the river. +This shows two of the Pennsylvania tunnel shields which have met far +below the Hudson River. The white arrow shows where each shield ends. +The platform of one shield on which the man stands corresponds exactly +with the platform of the other shield. As may be imagined, it takes +very careful and skillful engineering and surveying work, both before +the work is begun and while it is being carried out, to enable tunnel +shields to meet like this. This part of the art of tunnelling would +take an article to itself.] + +When the shield has been pushed across the entire length of the water +way which has to be tunnelled, and the whole of the iron tube or shell +is in place, a thick lining of concrete is placed inside the iron shell +to protect it and make the tunnel stronger. As an added safeguard +wherever the tunnel is in rock, gravel, strong clay or other ground +which is not so soft that it does not close tightly in on the outside +of the tube, liquid cement is forced by compressed air through holes +made in the iron plates for this purpose. This liquid cement enters +every pore or crevice in the surrounding ground and when it has set +hard it still further protects the iron with a coating of cement. +Pieces have been cut out of the iron lining of a tunnel built under the +river Thames at London, England, in 1869, which showed that the iron +at all places was as good as the day it was first put in forty years +before, and iron put in the lining of the Hudson River Tunnel about +1878 when removed after thirty years was in perfect condition. + +[Illustration: SHIELD AT END OF JOURNEY + +Sometimes, however, shields are not driven to meet one another, but end +their journey at some shaft or in some other tunnel previously built, +after having gone through thousands of feet of all kinds of ground, +from the hardest rock, which had to be blasted out foot by foot before +the shield could advance, through hard pan, gravel, boulders, piles, +rip-rap, made ground and mud so soft that it flows like melted butter. +Naturally, after an experience like this a shield does not look as +spick and span as when it started in life. This photograph shows one +of the shields of the Hudson and Manhattan Railroad in New York just +reaching the end of its journey, battered and bent but still in the +ring.] + +[Illustration: This shows a piece of curved tunnel near Morton Street, +on the Hudson and Manhattan Railroad, and is given because of the clear +showing it gives of the iron lining. The track and floor are only the +temporary roads for use during construction.] + +[Illustration: Sometimes it is necessary to make borings of the ground +below the tunnels. In some of these bore holes vast quantities of water +are found at a much higher pressure than the tunnel compressed air. +This picture shows a spouting bore hole in one of the Pennsylvania +tunnels during construction.] + +[Illustration: The last thing to do before laying the track is to put +the concrete inside the iron lining. This picture shows this work going +on and the wooden forms or ribs for holding up the concrete while it is +setting.] + +[Illustration: THE LAND END OF A GREAT TUNNEL UNDER THE HUDSON + +This view is given to show how complicated an underground structure +may have to be made to take care of the requirements of traffic. This +view shows the three great reinforced concrete caissons sunk through +the earth at Jersey City in order to contain the switches and crossings +required to form the New Jersey connections of the uptown and downtown +tunnels of the Hudson and Manhattan Railroad. + +These caissons were sunk under air pressure by excavating below them +just as though they were tunnels turned up on end. In sinking these +caissons the material passed through was water-logged made ground, and +the hulls of two sunken canal boats were encountered and had to be cut +into pieces small enough to be taken out through the locks. + +The usual passenger rushing at high speed in the trains between Jersey +City and Newark and New York has little idea of the very complicated +structure necessary to allow of his doing so. + +The information in this article was supplied by Jacobs & Davies, Inc., +Consulting Engineers, 30 Church Street, New York, the Engineers for the +Pennsylvania Railroad, Hudson River Tunnels, the Hudson and Manhattan +Railroad, and many other tunnels in various parts of the world. + +The illustrations were kindly supplied by the Pennsylvania Railroad and +the Hudson and Manhattan Railroad.] + +~DANGERS OF TUNNEL BUILDING~ + +This account of tunnelling by shield and compressed air is very +short and gives no more than a bare statement of the principles and +chief methods of such work. Nothing has been said of the engineering +difficulties involved in the design of such work, nor of the delicate +surveying work necessary if one should hope to start two shields a +mile or two apart and have them meet as shown in Fig. 13 like two +great glass tumblers placed rim to rim after having travelled through +thousands of feet of every kind of ground. Nothing has been said of the +men who work on this most arduous form of subterranean navigation, how +they cheerfully face the dark and the water ever threatening above them +and the unseen but not less deadly ally, and yet foe, the compressed +air, with its dreaded result, the bends, or the men on the surface +who keep the air compressors running without pause or stop day in and +day out until the work is done so that their comrades below may work +in safety. Nothing has been said of the curious accidents that are +liable to occur as when the air pressure in the tunnel gets too high, +overbalances the water pressure and blows a hole through the river-bed +and forms a geyser in the river above. It gives no account of the +special difficulties which arise when special conditions are found; +for example, when the lower part of the tunnel is in rock and the +upper part is in soft material. In fact it is nothing more than a bare +outline but it hoped that some, who may not be clear in their minds as +to how tunnels are built, may learn some of the first principles of +this most romantic kind of work from this bald narrative. + + + + +Why Do My Teeth Chatter? + + +Your teeth chatter because when you are cold in a way that makes your +teeth chatter the little muscles which close the jaw act in a series of +quick little contractions which pull the jaw up, and then let it fall +by its own weight. This is repeated many times and, as the action is +quick, the chattering occurs. It is a peculiar thing that this occurs +in spite of the will or brain, when, as a matter of fact, these muscles +which operate the jaws are especially under the control of the brain. +The chattering is really a spasm caused by the cold, and all spasms act +independent of the will. Cold seems to act on the jaw muscles a good +deal like some poisons which cause spasms. + + + + +Where Did All the Water in the Oceans Come From? + + +No, it did not come from the rivers which empty themselves into the +oceans, because the oceans were there before the rivers existed. Part +of it comes from the rivers now, but only a little in comparison to all +the water there is in the ocean. I will try to tell you simply how all +the water got into the ocean. + +There was a time when there was no water on the earth at all. That was +when the earth was red hot, just as it is to-day on the inside, and at +that time all the water we have to-day was up in the air in the form of +gases. Strange as it may seem to you, if you take two gases, one called +hydrogen and the other oxygen, and mix them the right way, they will +turn into water, and if you had the right kind of chemical apparatus +you could take water and turn it into these gases again. When, then, +the earth was still all red hot, all of our water was up in the air in +the form of these two gases. Then, later on, when the amount of heat on +the earth was just right to make these gases mix together, the water +came down out of the air in great quantities, and there was so much of +it that it completely covered the whole earth and no land was visible. +Later on, for various reasons, mountains were thrown up on the earth’s +surface by great earthquakes, and every time a mountain or a high place +was formed there had to be a hole or low place some place else, and the +water ran into these low places and stayed there, and that uncovered +more of the land, because there wasn’t enough water to fill all the +holes and cover the land too, and that is what makes our continents +and islands and all of the land we see. There is now about three times +as much earth covered with water as there is land. Of course, the sun +is always picking up water through what is called evaporation, which +means that it is taken into the air in the form of gases. Later it +comes down again in the form of rain and falls into the oceans or on +the land, where it sinks in, finally finding a stream or river, and +sooner or later gets back into the ocean again. + + + + +Why Don’t the Water in the Ocean Sink In? + + +This is due to the fact that there is a kind of substance at the +bottom of the ocean which the water cannot penetrate, in spite of the +tremendous pressure which the great body of deep water exerts. In all +places where the bottom of the ocean has a covering which water can +sink into it does so, but there are such a few places where this is +possible, by comparison, that the amount that gets out that way is not +noticeable. This water, if it can keep on going, will eventually reach +the inside of the earth, where it is red hot, and is turned into steam. + + + + +Where Does the Water in the Ocean Go at Low Tide? + + +To get to the answer of this you must know something about the tides. +The tide is caused by the pull of the moon on the waters in the ocean. +The moon revolves about the earth once each day and has the ability to +draw up the waters in the ocean toward it, as we have seen in our study +of the tides. + +Now, when it is high tide in one place it is low tide in another. The +moon does not make more water, but only pulls it toward it from side to +side. When it is low tide where we are the water has simply moved as a +body toward the place where it is high tide. + +The tides act a good deal like a see-saw, except that they move from +side to side instead of up and down. When one end of the see-saw goes +up the other end goes down, and when the “down” end comes up the other +end goes down. So the answer to your question really is that at low +tide the water which made it high tide a few hours before has gone to +some place where it is at that moment high tide. + + + + +Why Does the Ocean Look Blue at Times and at Other Times Green? + + +Sometimes when we look at the ocean from the pavilion or while on the +sand of our favorite bathing beach the water in the ocean looks very +beautifully blue, and on other days will look dark green from the same +point. Why is it? If you will stop to think that at night when there is +no moon or other light the water in the ocean looks black, I think you +will soon be on the right track to answer the question yourself. + +When the sky is blue--the kind of blue we like to see in the sky when +we are at the beach--the water in the ocean is blue, because the sea +reflects the color of the sky, and when the sky is overcast and gray +the color reflected by the sea will be gray also. + +But, say you, sometimes the water in the ocean is dark green, and yet +the sky is never green. Quite true, and I will try to tell you what +produces the green color. This happens sometimes where the water is +shallow, either near the shore or out further where there is a sandbar +or other shallow place. Sometimes at such points the sunlight strikes +the water at such an angle that the rays go clear to the bottom and are +reflected from that point--the bottom--to our eyes. In such a case the +light will be changed through a combination of the color of the bottom +at that point and the color of the sky itself at the time to make the +color green as it is reflected to our eyes from the bottom. + + + + +Why Does Water Run? + + +Water runs because it has not enough of anything in it to make it stick +together. + +In school language we call this sticking-together-thing “cohesion.” +The principle of cohesion makes all the difference there is, so to +speak, between solids, liquids and gases. A brick, a stone, a stick +of wood, or a piece of iron and all other solid substances have a +certain amount of this property of cohesion, and the particles stick +together, enabling us to build buildings and other things which become +permanent structures. These solid substances are either naturally +cohesive or else man, as in the case of the brick, has brought together +certain things with little or no cohesion and made them stick together +permanently. In the case of the brick, he takes a quantity of clay, +which is cohesive only to a certain degree, bakes it in an oven and +it becomes hard enough--more cohesive--so that he can pile one on top +of the other and make a building. Then he puts sand, mixed with other +things--lime and water--between the bricks to hold the bricks together, +and makes a structure that will last. Two bricks have no natural +cohesion for each other and, therefore, they can only be held together +by something that has cohesion within itself and also for the bricks. +The lime, sand and water make mortar which is cohesive when properly +mixed, while in themselves neither lime nor sand have much cohesive +property, and water has none at all. + +Liquids have little or no cohesion. Water has none, or very little. +Syrup has a good deal more, but will run over the edge of a piece of +bread and butter if you are not careful. + +Gases have no cohesive properties at all and, therefore, fly all over +the place, through any opening they can find, either at the top of the +room or under the crack of the door. They are always trying to get to +some place else and will keep moving as long as not confined. Gases can +move in any direction. + +Liquids, however, while they are inclined to be constantly on the move, +can only go in one direction--down hill, and they go down fast or slow +if there is a chance, in proportion to the amount of stick-together +properties they have. Liquids can never go up of their own accord, +excepting in the process of evaporation, and then only when changed +into gases. A lake of water will dry up completely by evaporation +unless fed by streams of water constantly flowing in, because +evaporation is constantly taking place wherever water is exposed to the +air. + + + + +What Makes the Water Boil? + + +What we call boiling in the water we see when water is put over a hot +fire long enough to make it boil, is the changing of the water from +what we generally regard it--a liquid--into gases. Water consists of +two gases--hydrogen and oxygen--in fact, two parts of hydrogen gas and +one part of oxygen gas when mixed will always make pure water. Now, +then, if liquid water is heated to a certain point or temperature it +turns into the two gases, oxygen and hydrogen, and comes to the top of +the water, which still remains in liquid form, in the form of a bubble +and explodes into the air--not a very loud explosion, but still an +explosion. The process of turning liquid water into gases is a gradual +one, and that is why the water does not all turn into one large bubble +at once and explode away. If you keep the fire going long enough, all +the water in the vessel will explode away into the air, a few bubbles +at a time. If you hold a cold plate over the vessel as the bubble +explodes you can catch some of these gases in the form of bubbles on +the under side of the plate, which are again liquid water. When the +water becomes hot enough it turns into bubbles and as bubbles rise +that is what makes the boiling you see. When the same gases then come +together again in a certain proportion under proper temperature they +turn into liquid water. + + + + +At What Point of Heat Does Water Boil? + + +The boiling point of water is the temperature at which it begins to +pass into the form of gases. This varies in different altitudes. At +the sea level the boiling point is at 212° Fahrenheit. On the top of +mountains, for instance, water would boil at a much lower temperature. +It would be possible to go high enough in a balloon so that the water +would fly from the pan in the form of gas without making the water hot. +Also, a mile below the level of the sea it would take many more degrees +of heat to make the water boil. It is said that high up in a balloon +you could not boil an egg hard in a pan of boiling water if you kept it +in the boiling water for an hour or more, whereas we know that an egg +will be hard-boiled if we keep it in boiling water down where we live +for more than five minutes. + +The degree of heat at which water passes away into the form of gases +is regulated by the pressure of the air on the water and other things +about us. At the average level in the United States where people +live the pressure of the air on everything is fifteen pounds to the +square inch, and at this pressure water boils only after it reaches a +temperature of 212° Fahrenheit. As we go up the mountains the pressure +becomes less and less as we go up. At the top of Mount Blanc, which is +15,781 feet high, water boils at 185° Fahrenheit. If we took a balloon +from the top of the mountain we would come to a height where there was +no air pressure at all. + + + + +What Do We Mean by Fahrenheit? + + +The name Fahrenheit is used to distinguish the kind of scale most +commonly used on thermometers in Great Britain and the United States. +Gabriel Daniel Fahrenheit, a native of Dantzic, made the first +thermometer on which this scale was used, and it is named after him. In +this scale for thermometers the space between the freezing point and +the boiling point is divided into 180 degrees--the point for freezing +being marked 32 degrees and the boiling point 212 degrees. + + + + +Why Can’t We Swim as Easily in Fresh Water as in Salt Water? + + +Our bodies are heavier than fresh water, i. e., a bulk of fresh water +equal to the size of our body would weigh less than our body, so that +the first tendency is to sink to the bottom if we find ourselves in +fresh water. If man had not learned to swim that is what he would +always do, sink to the bottom; but having learned how to keep from +sinking, he is able to swim in fresh water. However, we find that an +amount of salt water equal to the bulk of a man in size is heavier than +an equal amount of fresh water, although such a bulk of ordinary salt +sea water will still weigh less than the man. A man will sink in salt +water also if he has not learned to swim or float, but he can keep up +with less effort in salt water, and also swim in it more easily. In +a nutshell, then, the answer to this question is that salt water is +heavier than fresh water. You can make salt water so full of salt that +it becomes heavier than a man. Great Salt Lake in Utah is so salty that +one cannot sink in it for this reason. You could drown yourself in it, +of course, by keeping your head under water, but whether in shallow +water or deep water you would not sink in Great Salt Lake. + + + + +Why Do We Say Some Water Is Hard and Other Water Soft? + + +What we call hard water contains certain salts which soft water does +not contain. This salt in hard water is lime or some other salts which +the water has picked up out of the ground as it passed through either +coming up or going down. On the other hand, we can guess after having +been told this much that if we can find any water that has not passed +through the ground, and, therefore, not had a chance to pick up any +salts, we will have soft water. From that point it is easy to guess, +then, that rain water must be soft water, and so it is. The water in +the cisterns, which is rain water, is soft water, and the kind we get +out of the wells is hard water. + +We do not like to wash either our faces or our clothes in hard water, +especially when it is necessary to use soap, because when we use soap +with hard water the soap undergoes chemical change which prevents its +dissolving in the water. Therefore, you cannot easily do a good job +of washing in hard water. On the other hand it is easy to dissolve +the soap in pure rain water or soft water and that is the kind we, +therefore, prefer for washing. + + + + +How Does Water Put a Fire Out? + + +This is at first a puzzling question, because back in your mind is the +thought that since hydrogen and oxygen are necessary to make a fire +burn, it seems strange that water, which is composed of oxygen and +hydrogen, will also put it out. + +A burning fire throws off heat, but if too much of the heat is taken +from the fire suddenly the temperature of the fire is sent down so far +below the point at which the oxygen of the air will combine with it +that the fire cannot burn. We speak commonly as though water thrown on +a fire drowns it. That is practically what happens. Scientifically what +happens is that the water thrown upon the fire absorbs so much of the +heat to itself that the temperature of the fire is reduced below the +point where oxygen will combine with the carbon in the burning material +and the fire goes out. + +To answer the unasked part of your question at the same time I will +say that hydrogen and oxygen when combined as water will put the fire +out rather than make it burn, more because when these gases take the +form of water they are already once burned, and you know that anything, +substance or gas, which has already been burned cannot be burned again. +It required great heat to make oxygen and hydrogen combine and form +water, and it also takes great heat to separate them again. So they are +really burned once before they become water. + + + + +Where Does the Rain Go? + + +Eventually almost all of the rain that falls runs into the rivers +and lakes and later finds its way into the ocean, where it is again +taken up into the air by the sun’s rays. But many other things happen +to parts of the rain which do not find their way into the ocean. In +the paved street, of course, where the water cannot sink in, it flows +into the gutter and thence into the sewer and on down to the river or +wherever it is that the sewers are emptied. You see, it depends very +much on what the earth’s surface is covered with at the place where +the rain falls. When it strikes where there is vegetation a great deal +of it stays in the soil at a depth of comparatively few feet. If it is +soil where trees and other plants grow a great deal of it is sucked up +from the ground by this vegetation and given back into the air through +the leaves and flowers. Some of the rain keeps sinking on down into the +earth until it strikes some substance like rock or clay, through which +it cannot sink, and then it follows along this until it finds something +it can get through and collects in a pool and forms an underground +lake, and may cause a spring to flow. Then there are also worms and +other forms of animal life in the earth which use up some of the water. +But it all gets back into the air eventually to come down some time +again in the form of rain. + + + + +Why Does Rain Make the Air Fresh? + + +The main answer to this question must be that the rain in coming down +through the air drives the dust and other impurities which are in the +air before it, and so cleans the air and makes it absolutely clean. +In addition to this it is now stated that since very often rain is +produced by electrical changes in the air, and that these electrical +changes produce a gas called ozone, which has a delightfully fresh +smell, it is this ozone that makes us say the air has become fresh. + +The air above our cities is almost constantly filled with smoke, +containing various poisonous gases, and these are driven away by the +falling rain. + +Then, too, there is always a greater or less accumulation of dirt, +garbage and other things in the cities which give off offensive smells +constantly, but which we do not notice always because we become used to +them. When the rain comes down it washes the streets and destroys these +smells, and that makes the air fresh and delightful to take into the +lungs. + +In the country the air is more nearly pure all the time, because the +things which spoil the air in the city are not present. + + + + +Is a Train Harder to Stop Than to Start? + + +The answer is yes. It is harder to stop a train than to start it, or +rather it takes more power. The speed of a train depends upon the +motive power. When a train is stopped and you wish to start it, you +must apply enough motive power to start it going. There must be enough +power to move the weight of the train and overcome the friction of the +wheels on the track. It is, of course, easier to move a thing that +weighs less than a heavier one. If you throw a ball ten feet into the +air, it will perhaps not sting your hand when you catch it on its +return; but, if you throw it one hundred feet into the air, it will +sting your hands when you catch it. Besides, it will come down faster +the last ten feet of the way than the ball which you threw only ten +feet into the air. This is because when movement is applied to anything +you add power to it. The ball which comes down from one hundred feet +in the air acquires more power in falling and it takes more power to +stop it. A train in motion has not only the power of the weight of the +train behind it, but also the additional weight which the movement of +the train has given it. Therefore, it takes more power to stop it than +to start it. To stop a train you must apply the same amount of power as +is in the moving train because the power to stop any moving thing must +always be at least as great as the power which is moving it. + + + + +What Makes the Knots In Boards? + + +We find knots in the boards which we notice in a lumber pile or in any +other place where boards happen to be, because the smaller limbs which +grow away from the larger limbs of trees grow from the inside as well +as the outside of the tree. + +When you see a knot in a board it means that before the tree was cut +down and the log sawed up into boards, a limb was growing out from the +inside of the tree at the spot where the knot occurs. + +You will also find that the wood in the knot is harder generally than +the rest of the board. This is because more strength is required at the +base of a limb and in the part of the limb which grew inside the tree +than in other parts, for the limb must be strong enough to support not +only the limb itself, but also the smaller limbs which grow out of it. + + + + +How Many Stars Are There? + + +Man may never know how many stars there are. The best we can do is +to figure on the number that can be seen with the largest telescopes +which have been invented, for, of course, you know there must be many +millions of them which to us are invisible. We have counted the stars +so far as we can see them; or, rather, so far as we can photograph +them. Astronomers have found that a photographic plate exposed to the +stars will show more of them than can be seen by the naked eye. This +is because the materials on a photographic plate are more sensitive +to the light of the stars than the human eye. By this method man has +been able in a way to count the stars he can see. It adds up to more +than a hundred million of them. Astronomers found this out by taking +photographs of the heavens at night, devoting one picture to each +section, until the entire heavens had been covered, and then counting +them. + +[Illustration: WHERE PAINT COMES FROM + +MAKING LEAD BUCKLES--THE FIRST STEP IN PAINT MAKING.] + + + + +The Story in a Can of Paint + + +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. + +[Illustration: HOW WHITE LEAD IS MADE + +FILLING THE STACK WITH LEAD BUCKLES.] + +[Illustration: LEAD BEING TAKEN OUT OF THE STACKS. + +The next step is to take an earthenware vessel, which resembles an +ordinary stone crock, and first pour into it a small quantity of acetic +acid, which is about the same as table vinegar. Then the crock or pot +is filled up with the lead buckles. + +Where this white lead is made in a large way many thousands of these +pots are placed in a building, the sides of which are walled up tight, +the spaces between the crocks being filled in with tan bark. After +the floor has been covered with a layer of these crocks, the layer is +covered with boards, in order to provide a foundation for setting in +the next layer of crocks and tan bark. The layer of boards also serves +as a floor to keep the tan bark from falling into the open crocks on +the tier below. This procedure is followed with tier after tier until +the building is completely filled. + +Corrosion of the metallic lead in the pots now begins, because the tan +bark generates some heat, becoming finally quite warm. This heat causes +the acetic acid or vinegar to throw off vapor or steam, which attacks +the metallic lead, causing it to decompose or corrode. This process +goes on for many weeks (sometimes as much as fifteen or sixteen weeks), +until those buckles of metallic lead have become a mass of white powder +and nearly all trace of the original metallic lead has disappeared.] + +[Illustration: A LEAD BUCKLE AFTER CORROSION.] + +[Illustration: A LEAD BUCKLE BEFORE CORROSION.] + +[Illustration: HOW OXIDE OF ZINC IS OBTAINED + +WASHING THE LEAD. SCREENS COVERED WITH CLOTH REMOVE ALL FOREIGN MATTER. + +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. + + + + +THE STORY IN A STEEL RAIL + + +[Illustration: A Blast Furnace. + +Molten iron is brought from the blast furnaces to the open-hearth +furnaces, and dumped into a receptacle called a mixer, the capacity of +which ranges from 400 tons to 1000 tons, depending upon the number of +furnaces to be served.] + +[Illustration: One-thousand-ton Mixer.] + + Pictures in this story by courtesy of Bethlehem Steel Co. + +[Illustration: INSIDE OF OPEN HEARTH FURNACE + +Charging Side of an Open-hearth Furnace. + +An open-hearth furnace consists of a long, shallow hearth, suitably +enclosed in fire-brick, and bound together with steel binding. The +furnace is heated by burning gas and air, which have previously been +preheated, so that a temperature is obtained in the furnace ranging +from 2900 to 3050 degrees Fahrenheit.] + +[Illustration: Pouring Side of an Open-Hearth Furnace. + +The open-hearth process consists of the purification of iron by +oxidizing out the impurities and burning out the carbon of the iron +until a tough and ductile steel is produced, which can be made of any +desired composition by the addition of the necessary quantities of +alloys just previous to tapping and pouring. The impurities in the iron +are oxidized by the slag lying on top of the metal, and the burning +out of the carbon, which is a very slow operation, is hastened by the +addition of iron ore, the oxygen of which combines with the carbon of +the iron and passes off is a gas going up the stack. + +When an open-hearth furnace is ready for a charge, a variable amount +of scrap, say 30 per cent of the total weight of material used for +the heat, is charged into the furnace. With this scrap is charged +sufficient lime or limestone to make the slag, as well as some iron ore +to assist in reducing the carbon of the iron. In about two or three +hours the required amount of molten iron is brought from the mixer in +ladles, and poured into the furnace on top of the scrap, lime and ore.] + + +[Illustration: MOLTEN STEEL BEING POURED LIKE WATER + +Molten Steel Being Poured Into Ladle. + +When the scrap has all been melted, a test is taken to determine the +amount of carbon remaining in the bath. Iron ore is added from time +to time until the carbon in the bath has been reduced to the desired +point, and the metal is sufficiently hot to pour. At this point +“recarburizers” (consisting of Ferro-Manganese, Ferro-Silicon, and +pig-iron, or coal) are added to get the required composition. The tap +hole at the back of the furnace is opened, and the steel is allowed to +run out into a ladle, the slag coming last and forming a blanket over +the steel in the ladle.] + +[Illustration: Crane Carrying Ingot and Soaking Pit Furnaces. + +The ladle is picked up by an electric crane and carried over cast-iron +moulds, which are set on cars, the steel being poured into the moulds, +resulting in steel ingots. A sufficient amount of time is allowed for +the steel to become chilled or set, when the cars are pushed under an +electric stripper, where the moulds are removed from the ingots. After +the ingots leave the stripper they are taken to the scales and weighed, +and after weighing are put into the soaking pits. The pits get their +name from the part they play in the heating of the steel for rolling. +When the steel ingot is stripped the outside of the ingot is cool +enough to hold the inside, which is still in a liquid state, and the +steel is put into the soaking pits to allow the inside to settle into a +solid mass, after which the ingot is reheated for rolling. The length +of time in the soaking pits depends upon the size of the ingot, as the +larger the ingot, the greater length of time is required to set. + +When the steel is ready for rolling it is taken from the pits by +overhead electric cranes, and placed into a dump buggy at the end of a +roller line, which leads to the blooming mill. The dump buggy derives +its name from the fact that when the ingot is placed into same in +an upright position, the buggy, in order to place the ingot into a +horizontal position on the roller line, dumps over, in the same way as +if one were to rock too far forward in a rocking-chair, the dump buggy +operating on the same principle.] + +[Illustration: GETTING READY TO MAKE A RAIL + +Blooming Mill and Engine. + +The ingot travels down the movable-roller line to the blooming-mill +rolls, which roll it down from a piece 19 inches by 23 inches to what +is known as an 8 inch by 8 inch bloom, which is the size usually used +in the manufacture of rails. The blooming mill derives its name from +the fact that after an ingot is rolled in same it is no longer called +an ingot, but a bloom. + +After leaving the blooming mill the bloom travels along another roller +line to the shears, where it is cut into two or three pieces, the +number of pieces depending on the size of the rail which is to be +rolled. The blooms are then lifted over the roller line at the shears +by a transfer crane, and placed on a traveling roller line which +connects with the rear of the reheating furnace. This furnace is about +35 feet long, and is so constructed that when the bloom is pushed in +at the rear of the furnace, another bloom drops from the front or +discharge end of the furnace.] + +[Illustration: THE INGOT BECOMES A RAIL + +The Ingot Becomes a Rail. + +The bloom dropping out, being sufficiently hot to roll into rails, +travels along another roller line to the roughing or first set of +rolls. Here the bloom is given five passes in the rolls, and is then +transferred to the strand or second set of rolls, where it receives +five additional passes; after this operation it is transferred to +the finishing or third set of rolls, in which it is given one pass. +The bloom has now been converted into a rail, and the rail travels +on another roller line to the hot saw, where it is cut into 33-foot +lengths, this being the standard length in this country for all rails. +The rails when hot are cut by the hot saw to lengths of about 33 feet +6¹⁄₂ inches, the allowance of inches being made for shrinkage in +cooling. It is difficult to believe that steel shrinks to this extent, +but this is a fact, and while the rails are cooling on the hotbeds +they have the appearance of being animated, as they move first one way +and then the other. After the rails are on the hotbed a sufficient +length of time to cool, they are taken from the hotbed and placed +on a traveling roller line, which takes them to an endless chain +conveyor. The statement that rails are put on hotbeds for cooling seems +paradoxical, but the hotbeds are so called because the rails are placed +on them while hot, and are left there until they have cooled. + +The endless-chain conveyor places the rails on another bed, from +which they are picked up by an electric crane and distributed to the +straightening presses, where all burrs (which have been caused by the +hot-sawing operation) are removed before the rails are straightened. +After straightening they are transferred to drill presses, where they +have holes drilled into them for the accommodation of the splice bar, +after which they are placed on the loading docks.] + +[Illustration: After being carefully examined by the railroad +company’s inspectors they are picked up from the loading docks by +electric magnets attached to a crane, and are placed in cars ready for +shipment.] + + + + +Who Made the First Felt Hat? + + +The felt hat is as old as Homer. The Greeks made them in skull-caps, +conical, truncated, narrow- or broad-brimmed. The Phrygian bonnet was +an elevated cap without a brim, the apex turned over in front. It is +known as the “cap of liberty.” An ancient figure of Liberty in the +times of Antonius Livius, A.D. 115, holds the cap in the right hand. +The Persians wore soft caps; plumed hats were the headdress of the +Syrian corps of Xerxes; the broad-brim was worn by the Macedonian +kings. Castor means a beaver. The Armenian captive wore a plug hat. +The merchants of the fourteenth century wore a Flanders beaver. +Charles VII, in 1469, wore a felt hat lined with red, and plumed. +The English men and women in 1510 wore close woolen or knitted caps; +two centuries ago hats were worn in the house. Pepys, in his diary, +wrote: “September, 1664, got a severe cold because I took off my hat at +dinner”; and again, in January, 1665, he got another cold by sitting +too long with his head bare, to allow his wife’s maid to comb his hair +and wash his ears; and Lord Clarendon, in his essay, speaking of the +decay of respect due the aged, says “that in his younger days he never +kept his hat on before those older than himself, except at dinner.” +In the thirteenth century Pope Innocent IV allowed the cardinals the +use of the scarlet cloth hat. The hats now in use are the cloth hat, +leather hat, paper hat, silk hat, opera hat, spring-brim hat, and straw +hat. + + + + +What Is the Hottest Spot on Earth? + + +The hottest regions on earth is said to be along the Persian Gulf, +where little or no rain falls. At Bahrein the arid shore has no fresh +water, yet a comparatively numerous population contrive to live there, +thanks to the copious springs which break forth from the bottom of the +sea. The fresh water is got by diving. The diver, sitting in his boat, +winds a great goat-skin bag around his left arm, the hand grasping +its mouth; then he takes in his right hand a heavy stone, to which is +attached a strong line, and thus equipped he plunges in, and quickly +reaches the bottom. Instantly opening the bag over the strong jet of +fresh water, he springs up the ascending current, at the same time +closing the bag, and is helped aboard. The stone is then hauled up, and +the diver, after taking breath, plunges in again. The source of the +copious submarine springs is thought to be in the green hills of Osman, +some 500 or 600 miles distant. + + + + +Where Do We Get Ivory? + + +Ivory is a hard substance, not unlike bone, of which the teeth of +most mammals chiefly consist, the dentine or tooth-substance which in +transverse sections shows lines of different color running in circular +arcs. It is used extensively for industrial purposes and is derived +from the elephant, walrus, hippopotamus, narwhal, and some other +animals. The ivory of the tusks of the African elephant is held in the +highest estimation by manufacturers; the tusks vary in size, ranging +from a few ounces in weight to 170 pounds. Holtzapffel states that +he saw fossil tusks on the banks of rivers of Northern Siberia which +weighed 186 pounds each. Ivory is simply tooth-substance of exceptional +hardness, toughness, and elasticity, due to the firmness and regularity +of the dentinal tubules which radiate from the axial pulp-cavity to the +periphery of the tooth. + + + + +How Did Trial by Jury Originate? + + +~WHY JURIES HAVE TWELVE MEN~ + +A jury consists of a certain number of men selected according to law +and sworn to inquire into and determine facts concerning a cause or +an accusation submitted to them, and to declare the truth according +to the evidence. The custom of trying accused persons before a jury, +as practised in this country and England, is the natural outgrowth of +rudimentary forms of trial in vogue among our Anglo-Saxon ancestors. +The present system of trial by jury is the result of a gradual growth +under the English Common Law. There is no special reason why twelve is +the usual number chosen for a complete jury except the necessity for +limiting the number. In a grand jury the number according to law must +not be less than twelve nor more than twenty-three, and twelve votes +are necessary to find an indictment. The ancient Romans also had a form +of trial before a presiding judge and a body of judices. The right of +trial by jury is guaranteed by the United States Constitution in all +criminal cases, and in civil cases where the amount in dispute exceeds +$20. A petit or trial jury consists of twelve men, selected by lot +from among the citizens residing within the jurisdiction of the court. +Their duty is to determine questions of fact in accordance with the +weight of testimony presented and report their finding to the presiding +judge. An impartial jury is assured by drawing by lot and then giving +the accused, in a criminal case, the right to dismiss a certain number +without reason and certain others for good cause. Each of the jurymen +must meet certain legal requirements as to capacity in general and +fitness for the particular case upon which he is to sit, and must take +an oath to decide without prejudice and according to the testimony. +A coroner’s jury or jury of inquest is usually composed of from six +to fifteen persons, summoned to inquire into the cause of sudden or +unexplained deaths. + + + + +Can Animals Foretell the Weather? + + +Certain movements on the part of the animal creation before a change of +weather appear to indicate a reasoning faculty. Such seems to be the +case with the common garden spider, which, on the approach of rainy or +windy weather, will be found to shorten and strengthen the guys of his +web, lengthening the same when the storm is over. There is a popular +superstition that it is unlucky for an angler to meet a single magpie, +but two of the birds together are a good omen. The reason is that the +birds foretell the coming of cold or stormy weather, and at such times, +instead of searching for food for their young in pairs, one will always +remain on the nest. Sea-gulls predict storms by assembling on the land, +as they know that the rain will bring earthworms and larvæ to the +surface. This, however, is merely a search for food, and is due to the +same instinct which teaches the swallow to fly high in fine weather, +and skim along the ground when foul is coming. They simply follow +the flies and gnats, which remain in the warm strata of the air. The +different tribes of wading birds always migrate before rain, likewise +to hunt for food. Many birds foretell rain by warning cries and uneasy +actions, and swine will carry hay and straw to hiding-places, oxen will +lick themselves the wrong way of the hair, sheep will bleat and skip +about, hogs turned out in the woods will come grunting and squealing, +colts will rub their backs against the ground, crows will gather in +crowds, crickets will sing more loudly, flies come into the house, +frogs croak and change color to a dingier hue, dogs eat grass, and +rooks soar like hawks. It is probable that many of these actions are +due to actual uneasiness, similar to that which all who are troubled +with corns or rheumatism experience before a storm, and are caused +both by the variation in barometric pressure and the changes in the +electrical condition of the atmosphere. + + + + +Nearest Approach Ever Made to Perpetual Motion in Mechanics. + + +An inventor has patented a double electric battery which seems to +come exceedingly near to perpetual motion. Instead of using the zinc +battery, he professes to have hit upon a solution which makes a battery +seven times as powerful as the zinc battery, with absolutely no waste +of material. The power of the battery grows gradually less in a few +hours of use, but returns to its original unit when allowed to rest a +few hours. He has two batteries so arranged that the power is shifted +from one to the other every three hours. A little machine has been +running for some years in the patent office at New York. Certain parts +of the mechanism are constructed of different expansive capacities, and +the machine is worked by the expansion and contraction of these under +the usual variations of temperature. In the Bodleian Library at Oxford +there is an apparatus which has chimed two little bells continuously +for forty years, by the energy of an apparently inexhaustible +“dry-pile” of very low electrical energy. A church clock in Brussels is +wound up by atmospheric expansion induced by the heat of the sun. As +long as the sun shines this clock will go till its works wear out. Mr. +D. L. Goff, a wealthy American, has in his hall an old-fashioned clock, +which, so long as the house is occupied, never runs down. Whenever the +front door is opened or closed, the winding arrangements of the clock, +which are connected with the door by a rod with gearing attachments, +are given a turn, so that the persons leaving and entering the house +keep the clock constantly wound up. + + + + +Do Plants Breathe? + + +Plants, like animals, breathe the air; plants breathe through their +leaves and stems just as animals do by means of their respiratory +organs. When a young plant is analyzed it is found to consist chiefly +of water, which is all removed from the soil; there is about 75 per +cent or more of this fluid present, and the rest is solid material. +Of this latter by far the most abundant constituent is carbon, almost +every atom of which is removed from the atmosphere by the vital +action of minute bodies contained in the green leaves. The carbon is +taken into the plant as carbonic acid gas. Plants also absorb oxygen, +hydrogen, and nitrogen from the atmosphere in different quantities +through their leaves, and also by means of their roots. These new +products stored are in turn used in building up the different organs +of the plant. Plants give off used-up moisture through their leaves, +just as animals perspire through the pores of their skins. Calculations +have been made as to the amount of water thus perspired by plants. The +sunflower, only 3¹⁄₂ ft. high, with 5,616 square inches of surface +exposed to the air, gives off as much moisture as a man. + + + + +What Depth of Snow Is Equivalent to an Inch of Rain? + + +Newly fallen snow having a depth of about 11¹⁄₃ inches is equivalent to +one inch of rain. A cubic foot of newly fallen snow weighs 5¹⁄₂ pounds +and a cubic foot of fresh or rain water weighs 62¹⁄₂ pounds or 1,000 +ounces. An inch of rain means a gallon of water spread over every two +square feet, or about a hundred tons to every acre. The density of +snow naturally varies a good deal according to the speed with which +it falls. Temperature, also, has much to do with its bulk. In cold, +crisp weather, when the thermometer registers several degrees of frost, +snow comes down light and dry; but in moist, cold weather, when the +temperature is only just below thirty-two degrees, the snow falls in +large, partially thawed flakes, and occupies much less space where it +falls than that which reaches the earth during the prevalence of a +greater degree of cold. + + + + +How Are the Stars Counted? + + +Stars are counted by means of the telescope and photography. The +Astronomer-Royal for Ireland, Sir Robert S. Ball, in one of his +lectures mentioned a photograph which had been obtained by Mr. Isaac +Roberts representing a small part of the constellation of the Swan. +The picture is about as large as the page of a copy-book, and it +is so crowded with stars that it would puzzle most people to count +them; but they have been counted by a patient person, and the number +is about 16,000. Many of these stars are too faint ever to be seen +in the greatest of telescopes yet erected. Attempts are now being +made to obtain a number of similar photographs which shall cover +the whole extent of the heavens. The task is indeed an immense one. +Assuming the plates used to be the same size as that above mentioned, +it would require at least 10,000 of them to represent the entire +sky. The counting of stars by the telescope was first reduced to a +system by the Herschels, who introduced “star-gauges,” which were +simply a calculation by averages. A telescope of 18 in. aperture, 20 +ft. focus, and a magnifying power of 180, giving a field of view 15 +in. in diameter, was used for the purpose. The process consisted in +directing this instrument to a part of the sky and counting the stars +in the field. This, repeated hundreds of times, gave a fair idea of the +average number of stars in a circle of 15 in. diameter in all parts of +the sky. From this as a basis it is possible to reckon the number of +stars in any known area. + + + + +How Is the Volume of Sound Measured? + + +Sound arises from vibrations giving a wave-like motion to the +surrounding atmosphere, the wave gradually enlarging as it leaves the +source of disturbance, while at the same time the motion of the air +particles becomes less and less. The simplest method of determining the +number of vibrations of a sound is by means of Savart’s apparatus. This +consists of two wheels--a toothed or cog-wheel and a driving-wheel. +They are so adjusted that the cog-wheel is made to revolve with great +rapidity, its teeth hitting upon a card fixed near it. The number of +revolutions is indicated by a counter attached to the axis of the +cog-wheel. Suppose that sound is traveling in the air at the rate +of 1,000 ft. per second, and that Savart’s wheel is giving a sound +produced by 200 taps on the card per second, it follows that in 1,000 +ft. there will be 200 waves or vibrations, and if there be 200 waves in +1,000 ft. each wave or vibration must be 5 ft. in length. The velocity +of sound through air varies with the temperature of the latter, but is +usually reckoned at 1,130 ft. per second. + + + + +At What Rate Does Thought Travel? + + +Thought travels 111 feet per second, or about a mile and a quarter per +minute. Elaborate experiments have been made by Professors Heimholtz, +Hersch, and Donders, to ascertain the facts on this question, the +result of which was that they found the process of thought varied in +rapidity in different individuals, children and old persons thinking +more slowly than people of middle age, and ignorant people more slowly +than the educated. It takes about two-fifths of a second to call +to mind the country in which a well-known town is situated, or the +language in which a familiar author wrote. We can think of the name +of the next month in half the time we need to think of the name of +the last month. It takes on the average one-third of a second to add +numbers containing one digit and half a second to multiply them. Those +used to reckoning can add two to three in less time than others; those +familiar with literature can remember more quickly than others that +Shakespeare wrote “Hamlet.” It takes longer to mention a month when a +season has been given than to say to what season a month belongs. The +time taken up in choosing a motion, the “will time,” can be measured as +well as the time taken up in perceiving. If it is not known which of +two colored lights is to be presented, and you offer to lift your right +hand if it be red and your left if it be blue, about one-thirteenth of +a second is necessary to initiate the correct motion. + + + + +What Is the Largest Tree In the World? + + +In San Francisco, encircled by a circus tent of ample dimensions, is a +section of the largest tree in the world--exceeding the diameter of the +famous tree of Calaveras by five feet. This monster of the vegetable +kingdom was discovered in 1874, on Tule River, Tulare County, about +seventy-five miles from Visalia. At some remote period its top had +been broken off by the elements, or some unknown forces, yet when it +was discovered it had an elevation of 240 feet. The trunk of the tree +was 111 feet in circumference, with a diameter of 35 feet 4 inches. +The section on exhibition is hollowed out, leaving about a foot of +bark and several inches of the wood. The interior is 100 feet in +circumference and 30 feet in diameter, and it has a seating capacity +of about 200. It was cut off from the tree about twelve feet above the +base, and required the labor of four men for nine days to chop it down. +In the center of the tree, and extending through its whole length, +was a rotten core about two feet in diameter, partially filled with a +soggy, decayed vegetation that had fallen into it from the top. In the +center of this cavity was found the trunk of a little tree of the same +species, having perfect bark on it, and showing regular growth. It was +of uniform diameter, an inch and a half all the way; and when the tree +fell and split open, this curious stem was traced for nearly 100 feet. +The rings in this monarch of the forest show its age to have been 4,840 +years. + + + + +Where Did the Term Yankees Originate? + + +This is a word said to be a corruption of Yengees, the Indian +pronunciation of English, or of the French “Anglais,” when referring +to the English Colonists. It was first applied to the New Englanders +by the British soldiers as a term of reproach, later by the English to +Americans generally, and still later to the people of the North by the +Southerners. + + + + +How Far Does the Air Extend? + + +It is, perhaps, generally known that enveloping the earth is a layer +of air fifty or more miles in thickness. Just how thick this layer is +we do not know, but we do know that it extends many miles from the +earth. You may assure yourselves of this in a very simple manner by +watching the shooting stars that may be seen on any clear night. These +are nothing but masses of rocks that give off light only when they +have been made red-hot by friction with the air in their rapid flight. +The fact that we often see these stars while they are still many miles +from the earth proves to us that the air through which they are passing +extends to that height. + + + + +What Makes Us Feel Hungry? + + +Hunger is a peculiar craving which we are accustomed to say comes +from the stomach. It is the business of the stomach to change such +food as we take into it in such a way that the rest of the organs of +the body which we have for the purpose can make blood out of it. When +you feel the sensation of hunger, it means that the blood-producing +system is calling on the stomach to furnish more blood-making material. +The stomach prepares the food for blood production by mixing with it +certain juices which the stomach is able to supply. As soon as the +stomach is then called upon to supply more blood-making material, it +goes to work on what is in the stomach and begins mixing things. If, +however, there is nothing in the stomach, the craving which we call +hunger is produced. It is, therefore, then not altogether the stomach +which makes us hungry, but the parts of our body which actually turn +the food into blood after the stomach has prepared it. + +To prove this it is only necessary to say that the sensation of hunger +will stop if food which is easily absorbed and, therefore, does not +need the preparation which the stomach generally gives, is introduced +into the system through other parts of the body, as, for instance, by +injecting it into the large intestine, which is a part of the body, the +food passes through after it leaves the stomach ordinarily. + + + + +What Makes Us Thirsty? + + +Thirst is a sensation of dryness and heat which is generally +communicated to us through the tongue and throat. The sensation of +thirst can be artificially produced by passing a current of air +over the membranes which cover the tongue and throat, but thirst is +naturally due to a shortage of water in the body. The human body +requires a great deal of water to keep it in condition, and when the +supply becomes low a warning is given to us by making the membranes of +the tongue and throat dry. + +In connection with thirst, however, as in the case of hunger, where +the warning is given by the stomach, thirst will be appeased by the +introduction of water, either into the blood, the stomach or the large +intestine, without having touched either the tongue or throat, which +proves that it is not our tongue or throat that is thirsty, but the +body itself. + + + + +What Is Pain and Why Does It Hurt? + + +Pain is the result of an injury to some part of our bodies, or a +disturbed condition--a change from the normal condition. Pain is caused +by nerves in the body. The network of nerves coming in big nerves from +the back bone or spinal chord branches out in all directions, and near +the surface of the skin they spread out like the tiny twigs of a tree, +covering every point of the body. Some parts of our bodies are more +sensitive than others. That is because the nerves are then nearer the +surface or else there are more nerves in that part. The heel is perhaps +the least sensitive part of the body, as the nerves do not lie so near +the surface there. + +Pain is not a thing which you can make a picture of or describe in +words. Pain is a sensation of the brain caused by a disturbance of +conditions in some part of the body. If you cut your finger, you cut +certain veins or arteries and also the tiny nerves in the finger. +The nerves immediately let the brain know that they are injured, and +the brain sets to work to have the damage repaired. But there is a +congestion right where the cut is. The veins being cut, the blood which +would ordinarily flow through them back to the heart, pours out into +the cut and the inside of your finger is thus exposed to the oxygen of +the air, and the action of the air on the exposed part helps to make +the pain. It is not your finger, however, that hurts. It is the shock +that your brain gets when you cut your finger that hurts. + +A pain in your stomach is a pain caused by something else than a cut. +If the stomach could always digest everything or any amount of stuff +you put in it, you would not have a stomach pain. But sometimes you +put things into your stomach through your mouth, of course, that the +stomach cannot handle. Or, it may be a combination of a number of +things that cause this unusual condition in your stomach. The stomach +makes a special effort to get rid of this troublesome substance and +generally succeeds eventually, but while the fight is going on, it +pains or hurts you. + +Pain is the result of a disturbance of the nerves. It is just the +opposite of gladness. We sometimes are so glad we feel good all over. +Pain is just the opposite. You can prove that pain is not a real thing +but only a sensation. Perhaps you have had toothache. You go to the +dentist and he kills the nerve or takes it out. After that you cannot +have the toothache in that tooth again, because there is no nerve there +to telegraph to the brain, even though the cause of the hurt still +exists. You cannot feel pain unless the brain knows about the injury. + + + + +What Is the Horizon? + + +Of course you know what the horizon is. It is easiest to see the +horizon at sea when out of sight of land. There, when you look in +any direction from the ship to the place where the sea and the sky +meet you see a line which, if you follow with your eye as you turn +completely around, makes a perfect circle. It looks as though it marked +the boundary of the earth. On land it is not easy to see as much of +the horizon at one time, because of buildings and trees and hills in +the woods and elsewhere, but if the land were perfectly smooth like +the sea and there were no trees or buildings or hills in the way, you +could see just as perfect a circle on land as on sea. This proves that +the horizon is a movable circle. On land it is where the earth and sky +appear to meet, and on water it is where sky and water appear to meet. + + + + +How Far Away Is the Horizon? + + +The actual distance of the horizon away from us depends altogether upon +the height above the sea level from which we are looking as far as we +can. The horizon is always as far away as we can see. At the seashore, +where we are practically on a level with the water, we cannot see so +far as when we are up on a bluff or hill overlooking the sea. The +higher we go up straight from a given point the greater the distance +we can see up to a certain point and the farther away the horizon will +appear. The height of the person looking, of course, figures in this, +because when you are at sea level it is only your feet really that are +at sea level (if you are standing up straight) and the distance of the +horizon is measured from the eye of the person looking. A boy or girl +of ten would be, say, a little over four feet high, and the eyes of +such a person would be about four feet above the level of the sea. At +that height the horizon would be about two and a half miles away. If +the eyes are six feet above sea level the distance of the horizon will +be about three miles, so that practically every one sees a different +horizon, that is, one that appears at a different distance. A hundred +feet above the level of the sea the horizon will be more than thirteen +miles away, while at 1000 feet altitude it would be 42 miles away, and +if you could go a mile into the air the horizon would appear 96 miles +from where you are. The higher you go the farther away the circle which +apparently marks the joining of the earth and sky appears. + + + + +Why Can We See Farther When We Are Up High? + + +Remember that the earth is round and you will probably be able to +answer the question yourself. This one, like most questions boys and +girls ask, only requires a little thought. The earth, of course, as we +have learned long ago, is a globe. When you look out on the land or the +sea from a high place you can see more of the earth’s round surface +before the curve of the earth’s surface takes things beyond the range +of vision. If you are on a bluff 100 feet high at the seashore and +looking toward a point where a ship is coming toward shore, you will be +able to see the ship much sooner than if you were at the sea level. In +exact words, you actually see more of the earth’s surface the higher +up you are, because, as you go up your position in relation to the +curvature of the earth’s surface changes. + + + + +What Makes Lobsters Turn Red? + + +When a lobster is taken out of the lobster trap with which the +fisherman traps him, he is green, but when he comes to the table as a +choice morsel of food his shell is red. We know that he has been boiled +and we know that he goes into the boiling water green and comes out +red. This change in the color of the shell of the lobster is the result +of the effect of boiling water on the coloring material in the shell. +When the lobster is put in the boiling water the process of boiling +produces a chemical change in the color material in the lobster’s +shell. There is no particular reason why the lobster should turn red, +excepting that that is the effect boiling water has on the coloring +matter in the shell. + + + + +Why Do We Have to Die? + + +Death must come to all things that have life. All matter in the world +is either living (animate) or dead (inanimate). Inanimate things do not +change. They remain always the same. We can change the form and size of +inanimate things, and particles of them even help to make up the bodies +of the living things, but what they are made of always remains what it +was. + +Death is one of the things that must occur if we are to continue to +have more life. The whole plan of living things includes the ability to +reproduce themselves. Every kind of life has the power to produce life +like itself and this process of reproduction is continuous. If there +were no death, then the world would soon be crowded with living things +to the point where there would be neither room nor food. + +[Illustration: WHERE WINDOW GLASS COMES FROM] + + Pictures herewith by courtesy of Pittsburgh Plate Glass Co. + + + + +Making Plate Glass + + +What Is the Difference Between Plate Glass and Window Glass? + +How is plate glass made? These questions are asked very frequently. The +two products are wholly unlike each other; and we wish to show wherein +lies the difference. We shall tell how plate glass is made; and we hope +to make it clear that great care, time and expense are involved in its +manufacture. + +The raw materials may be said to be virtually the same in plate glass +as in window glass; the main difference being that in plate glass +greater care is exercised in selecting and purifying the ingredients. +Window glass is made with a blow-pipe. The work requires skill on the +part of the operator; but the process is quite simple and rapid. And +the result is, naturally, a comparatively ordinary and indifferent +product. On the other hand, the superb quality of plate glass is owing +to the elaborate method of producing it. + +Commercial plate glass was first made in France somewhat more than two +hundred years ago; although glass in one form or another has been in +use for many centuries. Apparently glass was known in Egypt fully four +thousand years ago. + +[Illustration: MINING SILICA] + +The materials used are silica (white sand), carbonate of soda (soda +ash), and lime. Other materials, as arsenic and charcoal, are used in +small proportions, but the main ingredients are the first three named. + +Probably it is little imagined that in the production of plate glass, +mining is involved in two or more forms (namely silica and coal), also +the quarrying of limestone, the chemical manufacture of soda ash on +a large scale, the reduction and treatment of fire clay to its right +consistency, an elaborate and expensive system of pot making; and the +melting, casting, rolling, annealing, grinding and polishing of the +glass. + +In special uses, as in beveled plates and mirrors, two more elaborate +processes must be added--beveling and silvering--all of which are +performed under the direction of experts aided by a large amount of +labor and expensive machinery. + +Pots of fire clay take so important a part in the successful +manufacture of plate glass that the subject deserves especial notice. +The different clays after being mined are exposed to the weather for +some time to bring about disintegration. + +~THE CLAY MUST BE TRAMPLED WITH BARE FEET~ + +At the proper stage finely sifted raw clay is mixed with coarse, burned +clay and water. This reduces liability of shrinkage and cracking. It +is then “pugged,” or kneaded in a mill; kept a long time (sometimes +a year) in storage bins to ripen; and afterwards goes through the +laborious process of “treading.” Nothing has thus far been found in +machinery by which the right kind of plasticity can be developed as +does this primitive treading by the bare feet of men. The clay must be +treaded, not once or twice, but many times. The building of pots is a +slow, tedious and time-killing affair; but this is most essential. + +~HOW MELTING POTS ARE MADE~ + +Without extreme care, some elements used in the making of the pots +might be fused into glass while undergoing the intense heat of the +furnace; or they might break in the handling. The average pot must hold +about a ton of molten glass, and the average furnace heat necessary is +about 3,000° Fahrenheit. The work is not continuous. Each workman has +several pots in hand at a time, and passes from one to another adding +only a few inches a day to each pot, so that a proper interval for +seasoning be given. After completion, comes the proper drying out of +the pots; and this is another feature in which the greatest scientific +care is required. No pot may be used until it has been left to season +for at least three months, and even a year is desirable. And after all +this trouble, the pot has but 25 days of usefulness. The pots form one +of the heavy items of expense in plate glass manufacture; and upon +their safety great things depend. + +[Illustration: POT MAKING.] + +[Illustration: MIXING THE CLAY. + +TRAMPLING THE CLAY.] + +[Illustration: SKIMMING THE POT.] + +[Illustration: CASTING PLATE GLASS.] + +~HOW THE HUGE PLATES OF GLASS ARE CAST~ + +The pot, having been first brought to the necessary high temperature, +is filled heaping full with its mixed “batch” of ground silica, soda, +lime, etc. Melting reduces the bulk so much that the pot is filled +three times before it contains a sufficient charge of metal. When the +proper molten stage is reached the pot is lifted out of the furnace +by a crane; is first carefully skimmed to remove surface impurities, +and then carried overhead by an electric tramway to the casting table. +This is a large, massive, flat table of iron, having as an attachment +a heavy iron roller which covers the full width, and arranged so as +to roll the entire length of the table. The sides of the table are +fitted with adjustable strips which permit the producing of plates of +different thicknesses. The pasty, or half-fluid glass metal is now +poured upon the table from the melting pot, and the roller quickly +passes over it, leaving a layer of uniform thickness. The heavy roller +is now moved out of the way, and then by means of a stowing tool the +red hot plate is shoved into an annealing oven. All of these stages +of the work have to be performed with remarkable speed, and by men of +long training and experience. The plates remain for several days in +the annealing oven, where the temperature is gradually reduced from an +intense heat at first, until at the end of the required period it is +no hotter than an ordinary room. + +[Illustration: PREPARING THE GRINDING TABLE.] + +When the plate is taken from the annealing oven it has a rough, opaque, +almost undulating appearance on the surfaces. It is only the surface, +however, for within it is as clear as crystal. First, it is submitted +for careful inspection, so that bubbles or other defects may be marked +for cutting out. It then goes to the cutter who takes off the rough +edges and squares it into the right dimensions; and thence to the +grinding room. + +[Illustration: HOW THE GLASS PLATES ARE GROUND + +GRINDING THE PLATES] + +The grinding table is a large flat revolving platform made of iron, +twenty-five feet or more in diameter. The plate must be carried from +the annealing oven to the grinding machines, and thence to the racks, +by men skilled in the art. Twenty men are required to carry the larger +plates of glass, ten on each side, using leather straps and stepping +together in perfect time. The lock-step is absolutely essential to +prevent accident. The grinding table is prepared by being flooded with +plaster of Paris and water; then the glass is carefully lowered, and a +number of men mount upon the plate and tramp it into place until it is +set. After this, greater security is obtained by pegging with prepared +wooden pins; and then the table is set in motion. The grinding is done +by revolving runners. Sharp sand is fed upon the table, and a stream of +water constantly flows over it. After the first cutting by the sand, +emery is used in a similar manner. + +The plates are inspected after leaving the grinding room, and if any +scratches or defects of any kind are found they are marked. Some of +these can be rubbed down by hand. There are also, not infrequently, +nicks and fractures found at this stage; and in such case the plate +must again be cut and squared. Afterward comes the polishing, which +is done on another special table. The polishing material is rouge, or +iron peroxide, applied with water, and the rubbing is done by blocks +of felt. Reciprocating machinery is so arranged that every part of the +plate is brought underneath the rubbing surface. + +The grinding and polishing has taken away from the original plate half +of its thickness, sometimes more. There is no saving of the material; +it has all been washed away. When to this waste is added the fact that +fully half of the original weight of lime and soda has been released +by the heat of the furnace, escaping into the atmosphere in fumes and +acids, one may begin to understand something of the cost of converting +the rough materials of sand, limestone and soda into beautiful plate +glass. + +~HOW MIRRORS ARE MADE~ + +In preparing plate glass for mirrors great care must be exercised in +the selection of the plates. This selection bears reference not only to +surface defects, but to the quality in general; defects which cannot +ordinarily be seen are magnified many fold after the glass has received +a covering of silver. + +[Illustration: BEVELING PLATES] + +In the process of beveling, the plate passes through the hands of +skilled workmen of five different divisions, namely: roughers, +emeriers, smoothers, white-wheelers and buffers; and different abrasive +materials are used in the order indicated by the titles. These +materials are sand, emery, natural sandstone imported from England, +pumice and rouge. + +The roughing mill is a circular cast-iron disk about 28 inches in +diameter, constructed so that the face or top of the mill revolves upon +a horizontal plane at a speed of about 250 revolutions per minute. The +sand is conveyed to the mill from above through a hopper simultaneously +with a stream of water which is played upon the sand to carry it to +the mill. The rougher places the edge of the plate upon the rapidly +revolving mill, and the cutting of the bevel is done by the passage +of the sand between the mill and the plate of glass. A bevel of any +desired width may be produced. Pattern plates containing incurves, +mitres, etc., require a practiced eye and great skill upon the part of +the operator. + +When the plate leaves the rougher’s hands the surface of the bevel has +been ground so deep by the coarse sand that polishing at this stage is +impossible. Consequently, in order to produce a surface fine enough +to render it susceptible of a high and brilliant polish it must go +through the various treatments we have mentioned. The emerier uses a +fine grade of emery on a mill similar in construction to a roughing +mill, which takes away considerable of the coarse surface given by the +first cutting. Then it goes to the smoother, who reduces the roughness +slowly by using a fine sandstone from England; then it goes to the +white-wheeler who operates an upright poplar-wood wheel using powdered +pumice stone as an abrasive; and then, as a last stage it reaches the +buffer, whose method of operation is shown in the illustration. The +buffer brings a high polish to the bevel by the use of rouge applied to +thick felt which covers his wheel. + +[Illustration: SILVERING MIRROR PLATES.] + +[Illustration: The two photographs here are of the same building taken +under contrasting conditions. The first picture was taken through a +window glazed with common window glass. It is an extreme example, to +be sure, but of a sort not infrequently seen. The second view shows +the same building taken through a window of polished, flawless plate +glass. An observing person can see this startling contrast any day as +he walks along a residence street. At intervals a front window will +be seen which gives a twisted, distorted reflection of the houses or +trees on the opposite side: this is window glass. The other kind--the +window that gives a sharp brilliant reflection--is _plate glass_. It +is practically impossible to obtain superior reflecting quality from +window glass. It can only be had from surfaces which have been ground +and polished.] + +The plate, after leaving the beveling room, is again carefully examined +for surface defects. These defects may consist of scratches caused +inadvertently by permitting the surface of the plate to come into +contact with the abrasive material. These scratches are removed by hand +polishing, which must be skillfully done; otherwise the reflection will +become distorted through over-polishing in a given area or spot. The +plate is then taken to a wash table where the surface to be silvered +is thoroughly washed with distilled water; after which it is taken +to a table that is covered with blankets, and which is heated to a +temperature of from 90° to 110°. The blanketing is to protect the plate +from being scratched, and also to catch all of the silver waste. The +silvering solution is nitrate of silver liquefied by a certain formula, +and is poured over the plate; the fluid having an appearance which to +the ordinary observer looks like nothing other than pure distilled +water. Within a few minutes the silver, aided by a reactory, added +prior to pouring, begins to precipitate upon the glass; the liquids +remaining above, and thus preventing air and impurities from coming +into contact with the silver. Such contact would produce oxidation. +After the silver is precipitated the plate is thoroughly dried, +shellacked and painted; after which it is ready for commercial use. + +Until about 25 years ago, practically all mirrors were silvered with +mercury. There have been two reasons for discouraging the use of +mercury for silvering; one being its injuriousness to the health of +the workmen. In some European countries stringent laws were enacted, +stipulating that men should work only a certain number of hours. + +Other hygienic stipulations, added to the fact that the use of mercury +was already very expensive, have tended to replace that process by the +use of nitrate of silver. + + + + +Why Is the Sky Blue? + + +This question puzzled every one who thought of it for a long time. +Even astronomers, the men who make a business of studying the skies, +and other learned men, puzzled their brains about it and searched for +the answer long ago, until finally, as always happens when a lot of +people study a subject, Professor John Tyndall, a noted scientist of +the last century, discovered the answer. The explanation follows: All +the light we have is sunlight, which is pure white light. This white +light is made up of rays of light of different colors. These rays are +red, orange, yellow, green, blue, indigo and violet. It takes all of +these different rays of light to make our white sunlight, and when +you separate sunlight into its original rays you always produce the +rays of light in the above colors and in the same order. This is only +true, however, when the sunlight is passed through an object which does +not absorb any of its rays. This is the arrangement of the different +colors of light found in the rainbow. The rainbow is formed by sunlight +passing into raindrops or vapor in such a way as to divide the sunlight +into the different colored rays of light. When the rainbow is formed +none of the rays are absorbed by raindrops or vapor through which the +sunlight passes. Some of these rays of light are known as short rays +and others as long rays. But when sunlight meets other things besides +those which make a pure rainbow, these other objects have the ability +to absorb some of the rays of colored light, and they throw off the +remainder. When these rays have been thrown off those which have been +absorbed make many different combinations, and thus are produced all of +the different colors we know, the various tints and shades of color, +according to composition and size. + +Now, then, to get back to the color of the sky, which is blue as we +know. The sky or air which surrounds the earth is filled with countless +tiny specks of what we may call dust--particles of solid things hanging +or floating in the air. These specks are of just the size and quality +that they catch and absorb part of the rays of light which form our +sunlight and throw off the rest of the rays, and the part which has +been absorbed forms the combination of color which makes our sky so +beautifully blue. Sometimes you notice, of course, that the sky is a +lighter or darker blue than at other times. This difference is due +to the kind and condition of tiny specks in the air at the time, and +to the direction or angle at which the sunlight strikes these tiny +particles. This fact brings up a question which you have not asked, but +which would come naturally as the result of your first. + + + + +What Makes the Colors of the Sunset? + + +The direction of the sun’s rays when they meet these large and small +particles in the air has a great deal to do with the combination of +colors that result as these objects absorb part of the rays and throw +off others. The sky is the most beautiful blue when the sun is high in +the sky. But when the sun is setting the light has a greater distance +to travel through the belt of air which surrounds the earth than +when it is high up over our heads. You know that if you stick a pin +straight down into an orange it won’t go in very far before it is clear +through the peel, but if you stick the pin into an orange along the +edge it will go through a great deal more of the peel than the other +way. That is the way it is with the sunset colors. The peel of the +orange is a good representation of the belt of air which surrounds the +earth. At sunset the light instead of coming straight down through the +belt of air, thus meeting the eye through the shortest possible amount +of air, strikes the air on a slant, and, therefore, travels through +a great deal more air and closer to the earth to reach it, with the +results that it meets a great many more of these little specks, besides +all the smoke and other things that hang in the air near the ground, +and we thus get many more colors, because some of the things in the air +absorb some of the rays and others absorb very different rays when the +light comes in this slanting way, and that is what makes the different +colors in the sunset. For this reason sunsets are often richer and more +beautiful in color when the air is not so pure, but has much dirt and +other matter floating about in it. + + + + +Are There Two Sides to the Rainbow? + + +No, there is only one side to the rainbow. The rainbow is made by +reflection of the rays of sunlight through drops of water in the air, +but you can never see a rainbow unless you are between it and the sun. +You could never see a rainbow if you were looking at the sun, and so +if you are looking at a rainbow you can be certain that anyone on +the other side of it could not see it, because they would have to be +looking right at the sun. The rainbow is always opposite to the sun and +there can never be two sides to it. + + + + +Do the Ends of the Rainbow Rest on Land? + + +The ends of the rainbow do not rest on anything. You see, the rainbow +is only the reflection of the sun’s rays thrown back to us by the +inside of the back of the raindrops, which are still in the sky after +the rain. Of course, if any of the drops of water touched the ground +they would cease to be raindrops and, therefore, could not reflect the +rays of the sunlight. So, what we think of as the ends of the rainbow +do not really exist at all. The rainbow is only a reflection of the +rays of sunlight from countless drops of water in the air, which the +sun’s rays must strike at a certain angle in order to reflect back the +light so we can see it. Where the sun’s rays do not strike the drops of +water at the right angle no light is reflected, and there is the end of +the rainbow. + + + + +What Causes the Different Colors of the Rainbow? + + +The colors of the rainbow, which are always the same, and are shown in +this order--red, orange, yellow, green, blue and violet--are sunlight +broken up into its original colors. It takes all of these colors in the +proportions in which they are mixed in the rainbow to make the pure +sunlight. These are known as the prismatic colors. As shown in another +answer to one of your puzzling questions, the rainbow is caused by the +rays of the sun passing into drops of water in the air and reflected +back to us with one part of the drop of water acting on it in such a +way as to break up the pure sunlight into these prismatic colors. When +a rainbow appears at a time when there is a great deal of sunlight, you +will generally see two rainbows. The inner rainbow is formed by the +rays of the sun that enter the upper part of the falling raindrops, and +the outer rainbow is formed by the rays that enter the under part of +the raindrops. In the inner or primary bow, as it is called, the colors +beginning at the outside ring of color are red, orange, yellow, green, +blue and violet, and being exactly reversed in the outer or secondary +bow. The secondary bow is also fainter. You may sometimes see smaller +rainbows, even if it has not been raining, when looking at a fountain +or waterfall. These are caused in exactly the same way. + + + + +What Makes the Hills Look Blue Sometimes? + + +This is due to the fact that when the hills look blue you are looking +at them at a distance, and there is a long stretch of air between you +and the hills. This air is filled with countless particles of dust +and other things, and what you see is not really blue hills, but the +reflection of the sun’s rays from the little particles in the air +striking your eye. The color is due to the angle at which the light +from the sun strikes these particles, and is reflected back to your eye +and partially due to the character of the particles in the air. + + + + +Do the Stars Really Shoot Down? + + +The answer is “No.” We have come to use the expression “shooting stars” +commonly, but we should probably be more correct if we said “shooting +rocks,” for the things we refer to commonly as “shooting stars” are +more like rocks than anything else. If any of the real stars were to +fall into the air surrounding the earth we should all be burned up by +the great heat developed long before it actually hit the earth, which +it would undoubtedly destroy. + +The things that fall and leave a streak of light are really only +pebbles, stones, rocks or pieces of iron and other substances that fall +from some place into the earth’s air belt. When they strike the air +at the speed at which they are falling the friction of the air makes +a heat that causes them to become luminous, and by far the greater +part of them is burned up before they get very near the earth. We call +them meteorites. Sometimes, though rarely, one will manage to strike +the earth, coming at such great speed and being so large that the air +has not been able to burn it up completely, and it will strike the +earth and sink deep down into the soil. In most museums can be seen +such meteorites that have been dug up after striking the earth. These +are constantly falling into the air surrounding the earth, but in the +day-time their light is not strong enough to be seen while the sun is +shining. + + + + +Will the Sky Ever Fall Down? + + +No, the sky can never fall down, because it is not made of the kind of +things that fall. We have become used to thinking of it as the roof +of the earth, a great dome-shaped roof, because in our little way of +looking at things we compared the earth and what is above it with the +houses in which we live. The sky is just space in which the heavenly +bodies revolve in their orbits. We cannot really ever see sky. We see +only the sun’s light reflected by the air belt which surrounds the +earth. In this air belt are the clouds which do come closer to the +land at times than at others, and this is apt to aid in giving us an +incorrect impression of this. + + + + +What Is the Milky Way? + + +The “Galaxy,” or “Milky Way,” as it is popularly called, is a luminous +circle extending completely around the heavens. It is produced by +myriads of stars, as can be seen when you look at it through a +telescope. It divides into two great branches at one point, which +travel for some distance separately and then reunite. It has also +several branches. At one point it spreads out very widely into a +fanlike shape. + + + + +Why Do They Call It the Milky Way? + + +The stars in the group are so numerous that they present to the naked +eye a whiteness like a stream of milk. To produce this effect there are +not hundreds of stars, nor thousands of them, but actually millions of +them. + +When you stop to think that each one of these stars in the Milky Way +is a sun like our own--some of them smaller, of course, but many of +them much larger--you begin to realize how impossible it is for man to +form any real idea of the magnitude and wonders of the earth. Here in +the Milky Way are so many suns like our own sun that they together as +we look at them form the particles of a path which makes the circle of +the heavens, and yet are so far away that to the naked eye each of them +looks to us like only one of countless drops of milk in a very large +stream of milk that goes around the whole sky. + + + + +Why Don’t the Stars Shine in the Day-time? + + +The stars do shine in the day-time. If you will go down into a deep +well or the open shaft of a deep mine and look up at the sky, of which +you can see a circular patch at the top of the well, you will be able +to see the stars in the day-time. The moon also shines in the day-time, +on some part of the earth. At certain times during the month you can +notice that the moon rises before the sun sets, and sometimes in the +morning you can still see the moon in the sky after the sun is up. +Usually you cannot see either the moon or the stars in the day-time, +because the light from the sun is so bright and strong that the light +of the stars and moon are lost in the brightness of the sun’s rays. +When the moon is visible before the sun sets or after the sun has risen +it is because the light of the sun is not so bright and strong at the +beginning or close of daylight. If you are fortunate enough some time +to witness a total eclipse of the sun you will be able to see the stars +in day-time without having to go down into a deep well or mine shaft. + + + + +How Far Does Space Reach? + + +Space surrounds all earths, planets, suns, and extends for an infinite +distance beyond each of them in all directions. It is impossible to +measure in terms of human knowledge how far space extends. It is one +of the things beyond the comprehension of the human mind, and for that +reason man can never know in miles or the number of millions of miles +how far it extends. Man has been able to measure the distance from +the earth of some of the stars, and some of the nearest of them are +millions of miles from the earth. Most of them are hundreds and even +thousands of million miles away, and when we stop to think that space +extends at least as far on the other sides of the stars as it does on +this side, and even beyond that, we can readily understand that it is +not only impossible to measure space, but also impossible to give in +words any conception of what its limits might be. + +There is one word--infinite--which we are forced to use in speaking of +the extent of space. Infinite means “without end,” unbounded, and so +man has come to use the word “infinite” in describing the extent of +space, and that is as near as any one can describe it. + + + + +What Does Horse Power Mean? + + +The term “horse power” is used in describing the amount of power +produced by an engine or motor. When man made the first engines he +needed some term to use in describing the amount of power his engine +could develop. Up to that time man had used the horse for turning the +wheels of his machinery and the horse to him naturally represented the +most powerful animal working for man. When engines came into use they +replaced the horses because they were capable of developing many times +the power of the horse. In finding an expression which would accurately +convey to the mind of another the power of a particular engine, it +was natural to say that this engine would do the work of five, ten or +more horses, and as this described it accurately and in a way that was +entirely clear, it became customary to describe the power of an engine +as so many times the power of one horse. + +To-day we still cling to the term “horse power” in describing the +strength of the engine, although the horse-power unit used to-day is +greater than the power of an average horse. To speak of an engine of +one horse power to-day means an engine that has the power to lift +30,000 pounds one foot in one minute. + +[Illustration: WHERE OUR COAL COMES FROM + +A COAL BREAKER. + +Coal is brought in mine cars from several mine shafts and slopes, +dumped onto a conveyor that runs on the inclined framework shown at +the right of the picture. At the top it is broken in rolls, sorted and +sized as it slides through the different screens, pickers, etc., and is +finally delivered into railroad cars.] + + + + +The Story in a Lump of Coal + + +How Did the Coal Get Into the Coal Mines? + +The heavy black mineral called coal, which we burn in our stoves +and furnaces, and use to heat the boilers of our engines was formed +from trees and plants of various sorts. Most of the coal was formed +thousands of years ago at a time when the atmosphere that envelopes the +earth contained a much larger proportion of carbonic acid gas than it +does now, and the climate of all regions of the earth was much warmer +than it now is. This period was known as the carboniferous age, that +is, the coal-making age, and its atmospheric conditions, favored the +growth of plants, so that the earth was covered with great forests, +of trees, giant ferns, and other plants, many of which are no longer +found on the earth. In the warm, moist, and carbon-laden atmosphere of +that period the growth of all kinds of plants was rapid and luxuriant, +and as fast as old trees fell and partially decayed, others grew up in +their places. In this way, thick layers of vegetable matter were formed +over the soil in which the plants grew. In many places, where these +beds were formed, the surface of the earth became depressed and the +water of the sea flowed over the beds of vegetable matter. + +Sediment of various kinds was deposited over the vegetable matter, and +in the course of centuries the sediment was transformed into rock. + +After the formation of the covering of sediment, the decay of the +vegetable matter was checked, but a slow change of another kind was +brought about by the pressure of the sedimentary deposits and the heat +to which the plant remains were subjected. The hydrogen and oxygen +which constituted the greater part of the plant substance was driven +off and the carbon left behind. This change took place very gradually, +through periods so long that we can only guess at their duration, but +we know that many beds of coal were formed from layers of vegetable +matter that were covered up many thousand years ago. + +[Illustration: MINE WORKERS THAT NEVER SEE DAYLIGHT + +Underground stable constructed of concrete and iron, with natural rock +roof to avoid danger of fire. Mules are only taken to surface when +mines are idle.] + +The coal first formed and submitted longest to pressure is known as +hard coal, or anthracite. It is pure black, or has a bluish metallic +luster. Its specific gravity is 1.46; which is about the same as that +of hard wood. Anthracite contains from 90 to 94 per cent. of carbon, +the remainder being composed of hydrogen, oxygen, and ash. + +[Illustration: The Mules and their drivers.--An important part of the +haulage system. Mules are kept in stables on surface at this mine and +driven in every day through slope or drift.] + +Hard coal may be called the ideal fuel and is especially adapted to +domestic heating purposes. It burns without smoke and produces great +heat. There is no soot deposit upon the walls of chimneys, and in good +stoves or furnaces the small amount of gas given off by it is consumed. +Anthracite is the least abundant of all the varieties of coal and is +much more costly than the other varieties. For this reason it is not +much used in manufacturing. + +[Illustration: HOW THE SLATE PICKERS WORK + +Boy slate pickers. Coal slides down the chutes. Boys pick out the slate +and rock and throw into chute alongside.] + +[Illustration: Spiral slate pickers do work of many boys. Coal and rock +start together at the top in the small inner spiral. The coal being +lighter slides faster, and in going around is carried over the edge +into the outer spiral, while the rock continues in the bottom.] + +The coal formed later is very different in composition and is called +bituminous or soft coal. Its name is derived from the fact that it +contains a soft substance called bitumen, which oozes out of the coal +when heat is applied to it. Soft coal contains from 75 to 85 per cent. +of carbon, some traces of sulphur, and a larger percentage of oxygen +and hydrogen than anthracite. When soft coal is heated in a closed +vessel or retort, the hydrogen and oxygen, in combination with some +carbon, are driven off. + +[Illustration: HOW A COAL MINE LOOKS INSIDE + +Shaft gate. One of the two cages in the shaft has just brought the men +to the surface; the other is at the bottom. Safety gate resting on top +of cage covers top of shaft when cage is down, as shown at right.] + +[Illustration: Section showing Anthracite Seams. Coal is shown black; +rock and dirt lighter; shaft tunnels and workings, white. Upper part of +“Mammoth” seam is stripped and quarried.] + +[Illustration: Lignite mine in Texas. Loaded mine cars ready to go to +surface.] + +[Illustration: HOW THE MINERS LOOSEN THE COAL + +Undercutting with pick. The man lying on his side cuts under the coal. +A light charge of powder exploded in a drill hole near the roof breaks +the coal down in large pieces.] + +Soft coal is black, and upon smooth surfaces it is glossy. It lacks the +bluish luster sometimes seen in hard coal and is much softer and more +easily broken. When handled it blackens the hands more than hard coal +does. In this kind of coal are frequently seen the outlines of leaves +and stems of plants that enter into its formation. Occasionally, trunks +of trees with roots extending down into the clay below the bed of coal +have been found. + +[Illustration: Undercutting in seam. A compressed air driven machine +undercuts deeper and faster than the man with a pick.] + +Soft coal has a specific gravity of 1.27. It burns with a yellow flame +which is larger than the flame from hard coal, but it does not emit so +high a degree of heat. Combustion, generally imperfect, gives rise to +offensive gases and to black smoke that concentrates in the air and +falls to the ground as soot, which blackens buildings, and, in winter, +noticeably discolors the snow. + +The formation of lignite has been observed in the timbers of some +old mines in Europe. In some of these mines wooden pillars have been +supporting the rocks above for four hundred years or longer, and in +that time the pressure of the rocks and other influences acting upon +the wood of the pillars have caused it to become transformed into a +brown substance resembling lignite. This fact tends to confirm the +theory of coal formation stated at the beginning of this article. The +proportion of carbon in lignite is never above 70 per cent., and the +ash indicates the presence of considerable earthy matter. It is chiefly +used in those forms of manufacture where a hot fire is not required. In +Europe it is used, to some extent, in heating the houses of the poorer +classes. + +Peat is regarded as the latest of the coal formations. In it, the +change in the vegetable matter has not extended beyond merely covering +it, and subjecting it to slight pressure. + +Peat is formed in marshy soils where there is a considerable growth +of plants that are constantly undergoing partial decay and becoming +covered by water. It consists of the roots and stems of the plants +matted together and mingled with some earthy material. When freshly +dug out of the bog or marsh in which it was formed there is always a +quantity of water in it, the amount being greatest in the peat found +nearest the surface and least in that at the bottom of the bed, where +the peat is not very different in appearance from lignite. + +Peat is used for fuel where wood is scarce and coal is high in price. +Recent experiments in saturating peat with petroleum, have shown that +in this way a form of fuel may be produced for which considerable value +is claimed. Its manufacture is confined to Southern Russia, where peat +is plentiful and petroleum is cheap. + + +Why Does Firedamp Explode in a Safety Lamp Without Producing an +Explosion of the Gas With Which the Lamp Is Surrounded? + +The passing of the flame from the lamp to the outside air is prevented +by the gauze. This splits the burning gas into little streamlets (784 +to each square inch of gauze), which are cooled below the point of +ignition, that is, are extinguished by coming in contact with the metal +of the gauze, so that the flame does not pass outside the lamp. In some +cases the explosion may be so great as to force the flame through the +gauze and thus ignite the gas outside. + + +Are There Any Conditions Under Which it Would Not Be Safe to Use a +Safety Lamp? + +~THE DANGERS TO THE MINERS~ + +The underground conditions affecting the safety of the lamp are +exposure in air-currents of high velocity by reason of which the flame +may be blown through or against the gauze, or exposure for too great +a time to mixtures of air and gas which will burn within the lamp and +thus heat the gauze. The dangerous velocity of air-currents begins at +about 500 feet a minute, but varies with the type of lamp, some being +much less sensitive to air-currents of high velocity than others. Other +conditions under which the lamp is not safe concern the lamp itself or +the one using it. The lamp is dangerous in the hands of inexperienced +persons or when the gauze is dirty or broken. If the gauze is dirty, +that portion absorbs the heat and may become hot enough to ignite the +outside gas; naturally any holes in the gauze will pass the flame. + +The safety lamp when left too long in air containing much explosive gas +may cause an explosion, and it is extinguished by certain unbreathable +gases. The electric lamp burns safely regardless of the atmosphere, +but gives no warning of poisonous or explosive gases. It is often used +by rescue men wearing oxygen helmets to enter mines full of poisonous +gases after explosions. + +[Illustration: THE LAMP WHICH SAVES MANY LIVES + +The safety lamp. The sheet iron bonnet or covering of the upper part +protects the gauze within from strong currents of air, while the glass +permits the light to be diffused. The above is a modern lamp similar to +a bonnetted Clanny lamp.] + +The safety lamp is dangerous when there is a hole in the gauze that +will permit the passage of flame to the outside, or when the gauze +is dirty, so that any particular spot may be overheated, or when the +velocity of the air is so great that the flame is blown through the +gauze, or (generally) when in the hands of an inexperienced person. The +unbonneted Davy lamp is not safe where the velocity of the air exceeds +360 feet per minute. The velocity with which the air strikes a lamp +carried against it is increased by the amount equal to the rate at +which the fireboss travels. If he walks at the rate of, say, 4 miles an +hour or 352 feet a minute (on the gangways he will usually have to move +faster than this to make his rounds on time) he will create by his own +motion (and in still air) a velocity practically the same as that at +which the unbonneted Davy is considered unsafe. + +[Illustration: Open oil lamp commonly worn on hat. Wick is inverted in +spout.] + +[Illustration: Acetylene or carbide lamp for cap or hand.] + + +History of the Safety Lamp. + +The safety lamp, the miner’s faithful and indispensable companion at +his dangerous work, has been, heretofore, considered as the invention +of the famous English scientist, Humphrey Davy, though the name of +George Stephenson, of locomotive fame, has also been mentioned in +this connection. Both came out with their inventions about the same +time, but neither of them is the real inventor of the safety lamp; for +there was, as proven by Wilhelm Nieman, a safety lamp in existence two +years before Davy’s invention became known. It was not inferior to the +latter, but rather surpassed it in illuminating power. Previous to +this, all the precaution employed for the prevention of the threatening +dangers of firedamp had been quite incomplete. One tried to thoroughly +ventilate the mines by fastening a burning torch to a large pole, which +was pushed ahead and exploded the gases. This was extremely dangerous +work which, in the Middle Ages, was generally done by a criminal, +in order that he might atone for his crimes, or by a penitent for +the benefit of mankind. The attempt to substitute for the open light +phosphorescent substances, encased in glass, was not much of a success. +An improvement was the so-called steel mill, invented about 1750 by +Carlyle Spedding, manager of a mine. This steel mill consisted of a +steel wheel which was put into rapid motion by means of a crank. By +pressing a firestone against the fast revolving wheel, an incessant +shower of sparks was produced giving a fairly good and absolutely safe +illumination. However, the running expenses of his apparatus, which +necessitated the continual services of one man, were very high; for +instance, the expenditure for light in a coal mine near Newcastle in +the year 1816 amounted to about $200 per week. Nevertheless, the steel +mill was very much appreciated and in use for a long time, only to be +slowly supplanted by the safety lamp. + +[Illustration: ELECTRIC CAP LAMP AND BATTERY. + +The safety lamp when left too long in air containing much explosive gas +may cause an explosion, and it is extinguished by certain unbreathable +gases. The electric lamp burns safely regardless of the atmosphere, +but gives no warning of poisonous or explosive gases. It is often used +by rescue men wearing oxygen helmets to enter mines full of poisonous +gases after explosions.] + +~THE MAN WHO INVENTED THE SAFETY LAMP~ + +At the beginning of the nineteenth century the existing coal mines +were worked to the limit and the catastrophies, caused by firedamp, +increased in an alarming manner. In fact the distress was so great that +in 1812 a society for the prevention of mine disasters was formed at +Sutherland, and the origin of the safety lamp can be traced back to +the efforts and labors of this organization. Dr. William Reid Clanny, +a retired ship’s surgeon, was probably the first to undertake the task +(in the year 1808), which he successfully finished with energy and +skill. He concentrated his efforts at first on the separation of the +flames from the surrounding atmosphere, but he did not succeed till the +latter part of 1812, when he constructed a lamp that seemed to meet +all requirements. The report of this invention was submitted to the +Royal Society of London, May 20, 1813, and was printed in the minutes +of that academy. The casing of this original safety lamp was closed +at the top and bottom by two open water tanks; the air was pumped in +by means of bellows and, passing in and out, had to go through both +these reservoirs which acted as valves, so to speak. The lamp proved to +be absolutely safe and was successfully introduced by the management +of Herrington Mill pit mine. The clumsy parts of this apparatus were +eliminated by its inventor by various improvements. The so-called steam +safety lamp was completed in December, 1815, and installed in several +mines. In the meanwhile, two competitors made their appearance. George +Stephenson had finished his lamp October 21, 1815, and Davy published +his first experiments November 9, 1815, in the Transactions of the +Royal Society of London. Clanny’s lamp, nevertheless, stood the test in +the face of this competition, through its much superior illuminating +power, and more particularly as it still continued to burn when the +Davy and Stephenson lamps had gone out. To Clanny, therefore, belongs +the distinction, in the history of invention, of having constructed the +first reliable safety lamp. + + + + +What Is a Metal? + + +The oldest known metals in the world are gold and silver, copper, iron, +tin and lead. They are to-day still the most useful and widely-used +metals. Some of the properties by which we distinguish metals are the +following: They are solid and not transparent; they have luster and +are heavy. Mercury is an exception to the rule; it is a liquid, though +yet a metal, and there is another, sodium, which is solid, though very +light. + + + + +What Is the Most Valuable Metal? + + +If you were guessing you would naturally say that gold is, of course, +the most valuable of the metals. But you would be wrong. The proper +answer to this is iron. We do not mean the pound for pound value, for +you could get much more for a pound of gold than for a pound of iron. +We mean in useful value--iron is in that sense the most valuable metal +known to man. This is true because iron is of such great service to man +in so many ways, and it is very fortunate that there is such a great +amount of it available for man’s purposes. Iron is not generally found +in a pure state in the mines. It is generally found compounded with +carbon and other substances, and we obtain pure iron by burning these +other substances out of the compound. + +Iron is put upon the market in three forms, which differ very much in +their properties. First, there is cast-iron. Iron in this form is hard, +easily fusible and quite brittle, as you will know if you ever broke a +lid on the kitchen range. In the form of cast-iron it cannot be forged +or welded. + +Next comes wrought-iron, which is quite soft, can be hammered out flat +or drawn out in the form of a wire and can be welded, but fusible only +at a high temperature. Third comes steel, the most wonderful thing we +produce with iron. It is also malleable, which means that it is capable +of being hammered out flat and can easily be welded, and this is the +great property of steel--it acquires when tempered a very high degree +of hardness, so that a sharp edge can be put on it, and when in that +shape it will easily cut wrought-iron. Ordinarily we make wrought-iron +and steel from iron that has been changed from its original state to +cast-iron. + +The term cast-iron is generally given to iron which has been melted and +cast in any form desired for use. Stoves are made in this way. The iron +is melted and then poured into a mold; while the product out of which +wrought-iron and steel are made is technically cast-iron, the term +pig-iron is used in speaking of iron which is cast for this purpose. + +The process by which pig-iron is changed into wrought-iron is called +_puddling_. The object of puddling, which is done in what is called a +reverberatory furnace (which is a furnace that reflects or drives back +the flame or heat) is to remove the carbon which is in the pig-iron. +This is done partly by the action of the oxygen of the air at high +temperature and partly by the action of the cinder formed by the +burning furnace. When this has been done the iron is made into balls of +a size convenient for handling. These are “shingled” by squeezing or +hammering and passed between rolls by which the iron is made to assume +any desired form. + +Now we come to steel, the most wonderful product or form in which we +take advantage of the value of iron. Steel was formerly made from +wrought-iron, so that you first had to get cast-iron, from which +you made wrought-iron, and eventually got steel by changing the +wrought-iron. Now we make steel direct from pig-iron. This is known as +the Bessemer process. + +The most noticeable feature in the chemical composition of the +different grades of iron and steel is found in the percentages of +carbon they contain. Pig-iron contains the most carbon; steel the next +lowest, and wrought-iron the least. + +Iron has been known to men from early historical times. The smelting +of iron ores is not any indication of advanced civilization either. +Savage tribes in many parts of the world practiced the art of smelting, +even before they could have learned it from people who had become +civilized. + + + + +Why Is Gold Called Precious? + + +Gold is called one of the precious metals because of its beautiful +color, its luster, and the fact that it does not rust or tarnish when +exposed to the air. It is the most ductile (can be stretched out into +the thinnest wire), and is also the most malleable (can be hammered +out into the thinnest sheet). It can be hammered into leaves so thin +that light will pass through them. Pure gold is so soft that it cannot +be used in that form in making gold coins or in making jewelry. Other +substances, generally copper, are added to it to make the gold coins +and jewelry hard. Sometimes silver is also added to the gold with +copper. The gold coins of the United States are made of nine parts of +gold to one of copper. The coins of France are the same, while the +coins of England are made of eleven parts of gold to one of copper. +The gold used for jewels and watch-cases varies from eight or nine to +eighteen carats fine. + +Another reason why gold is called a precious metal is that it is very +difficult to dissolve it. None of the acids alone will dissolve gold, +and only two of them when mixed together will do so. These are nitric +acid and hydrochloric acid. When these two acids are mixed and gold put +into the mixture the gold will disappear. + + + + +What Do We Mean By 18-Carat Fine? + + +We often hear people in speaking of their watches say, “It is an +18-carat case.” Others speak of 14-carat watches or 22-carat or +solid-gold rings. + +When you see the marks on a watch-case or the inside of a gold ring +they read 18 K or 14 K, or whatever number of carats the maker wishes +to indicate. A piece of gold jewelry marked 18 K or 18 carats means +that it is three-fourths pure gold. In arranging this basis of marking +things made of gold, absolutely pure gold is called 24 carats. Then if +two, six or ten twenty-fourths of alloy has been added, the amount of +the alloy is deducted from twenty-four, and the result is either 22, 18 +or 14 carats fine, and so on. On ordinary articles made by jewelers the +amount of pure gold used is seldom over 18 carats, or three-fourths. +Weddings rings (and these are considered solid gold) are generally made +22 carats fine, that is, there are only two twenty-fourth parts of +alloy in them. + + + + +Why Does Silver Tarnish? + + +Silver is a remarkably white metal, which is associated with gold as +one of the precious metals. It is harder than gold and will not rust, +although it will tarnish, which gold will not, when exposed to certain +kinds of air. + +The silver tarnishes when it is exposed to any kind of air that has +sulphur mixed in it. It ranks below gold as a precious metal for use in +making ornaments and is not so costly, because there is a great deal +more of it to be found in the world. + +While silver is somewhat harder than gold, it is still not sufficiently +hard to use pure for making coins, so, as in the case of the gold +coins, it is mixed with something else--copper--to harden it. Otherwise +our dimes and quarters would wear out too rapidly. Our silver coins are +made of nine parts of silver to one of copper. The coins of France are +in the same proportion, while the silver coins of England are made of +92¹⁄₂ parts of silver to 7¹⁄₂ parts of copper. German silver coins are +made of three parts of silver and one of copper. + + + + +Why Do We Use Copper Telegraph Wires? + + +One of the characteristics which distinguishes copper is its color--a +peculiar red. It stands next to gold and silver in ductility and +malleability, and comes next to iron and steel in tenacity--which +means the ability of its tiny particles to hang on to each other. +That is why copper wire bends instead of breaking when you twist +it. But that is not the only reason, although an important part of +the reason, why we use copper for telegraph wires. Copper is an +extremely good conductor of electricity when it is pure. So are gold +and silver, but we cannot afford to buy gold and silver wires for the +telegraph, telephone and other wires, and if we used such wires the +cost of the equipment would be so great that we could not afford to +have telephones in our homes. But there is a great deal of copper in +the world and it is very cheap, and so it makes an ideal element for +use in things through which electricity is to pass. When you compound +it with other substances it loses some of its conductivity. Copper +is used extensively in many ways in the world. This book is printed, +for instance, from copper electrotype plates. The whole business of +electrotyping is based on the use of copper. + + + + +Why Is Lead So Heavy? + + +Lead is a white metal and is noted for its softness and durability. It +has a luster when freshly cut, but becomes dull quite soon after the +freshly-cut surface is exposed to the air. Lead is the softest metal in +general use. It can be cut with an ordinary knife. It can be rolled out +into thin sheets, but cannot be drawn out into wire. + +Lead is a very dense metal, that is, its particles are very compact +and there is no room for air to circulate in between these particles. +A piece of wood is lighter than a piece of lead of exactly equal bulk, +because the little particles which make up the piece of wood are not +very close together, and there is a lot of air in the ordinary piece of +wood, while this is not true of the lead. + +A great deal of lead is used in making pipes for plumbing. This is +because lead pipe is comparatively cheap, although you might not think +so when you think of the general conclusions we have been brought to +form about plumbers and everything connected with them. Lead pipe is +easily bent in any direction also, and is particularly good for use in +plumbing for that reason. + +Another wide use of lead is in making paints--white lead being the base +used in making oil paints. The process of making white lead for paint +is quite interesting and pictures of it are shown in “The Story In a +Can of Paint” in another part of “The Book of Wonders.” + + + + +Why Are Cooking Utensils Made of Tin? + + +Tin is the least important of the six useful metals. It is also +inferior in many ways to the others in this group of elements, but is +tougher than lead and will make a better wire, though not a really good +one. It has a whiteness and a luster that are not tarnished by ordinary +temperature and is cheap. That is why it is used in making cooking +utensils, pans, etc., and for roofs. But the pans, roofs, etc., are not +pure tin. They are thin sheets of iron coated with tin. Pure tin would +not be strong enough for these purposes, so a sheet of iron is first +taken to supply the strength and then covered with tin to improve the +appearance of the tin pans and keep them from rusting rapidly. + + + + +What Is Gravitation? + + +Gravitation is the result of the attraction which every body, no matter +what its size, has for every other body. It is a strange force and +difficult to explain in plain words. It is what keeps the heavenly +bodies in their paths. Every one of the planets is held in its path +by gravitation and every object on each of the planets is kept on the +planet by gravitation. We can come nearer understanding gravitation by +studying the effect of the attraction of gravitation on our own earth +and the objects on it. When you throw a ball or a stone into the air +it is the attraction of gravitation that causes it to come back. If +this were not so the stone would go on up and up and would keep on +going forever. If it were not for this wonderful force you could jump +into the air and just keep on going up with nothing to bring you back. +The reason you do not pull the earth toward you is because the body or +mass with the greater bulk has always the greater pulling power. + +This is a wonderful force. It cannot be produced nor can it be +destroyed or lessened. It just is. It acts between all pairs of +bodies. If other bodies come between any pair of bodies the attraction +of gravity between the two outside bodies is neither lessened or +increased, and yet each of the outside bodies will have an independent +attraction or pull on the body which is in between. + +No particle of time is spent by the transmission of the force of +gravity from one body to another, no matter how far apart they may be. +The only effect that distance has on the attraction of gravitation is +to lessen its force. Any body which is being pulled through gravity +toward another body would fall toward the center of the attracting body +if all the force of attraction from all other bodies were removed. + + + + +What Is Specific Gravity? + + +Specific gravity is the ratio of weight of a given bulk of any +substance to that of a standard substance. The substances taken as +the standard for solids and liquids is water, and air or hydrogen for +gases. Since the weights of different bodies are in proportion to their +masses, it follows that the specific gravity of any body is the same +as its density, and we now generally use the term “density” instead of +specific gravity. + +To find, for instance, the specific gravity of a given bulk of silver, +we must take an equal bulk of water and weigh it. Then we also weigh +the silver. We find that the silver weighs ten and a half times as much +as the water, and so the specific gravity of silver is 10.5. If you +will bear in mind that water is the standard used for measuring the +specific gravity of solids and liquids, and that air or hydrogen are +used as standards for the gases, you will always know what the figures +after the words specific gravity mean. + + + + +Why Do We See Stars When Hit On the Eye? + + +We do not really see stars, of course, when we are hit on the eye or +when we fall in such a way as to bump the front of our heads. What we +do see, or think we see, is light. + +To understand this we must go back to the explanation of the five +senses--sight, hearing, feeling, tasting and touching. Now, each of +these senses has a special set of nerves through which the sensations +received by each of the senses is communicated to the brain and, as +a rule, these special nerves receive no sensations excepting those +which occur in their own particular field of usefulness. The eye then +has nerves of vision; the nose, nerves of smell; the ear, nerves of +hearing; the mouth, nerves of taste, and the entire body nerves of +touch. As we have seen then, these special nerves are susceptible of +receiving impressions or sensations only in their particular field. +But, if you should be able to rouse the nerves of smell in an entirely +artificial way and give them a sensation, they might easily act very +much as though they smelled something. We find this often in the nerves +of touch when we think we feel something when we do not. + +Now, when some one hits you in the eye, the nerves of vision are +disturbed in such a way as to produce upon the brain the sensation of +seeing light. In other words, you cannot affect the eye nerves without +causing the sensation of light, and that is just what happens when some +one hits you in the eye. + +[Illustration: “ARGONAUT, JUNIOR.” + +Experimental Boat, 1894.] + +[Illustration: “ARGONAUT THE FIRST.” + +Built 1896-1897.] + + + + +The Story in a Submarine Boat + + +How Can a Ship Sail Under Water? + +Up to a few years ago the stories we could tell about the ships that +sail beneath the water were the creations of the minds of writers of +fiction, like the author of “Twenty Thousand Leagues Under the Sea,” +but to-day we can read of many actual trips beneath the water by the +brave men who man our submarines. We never dreamed that the great story +of Jules Verne would be realized in the little but very destructive +ships of war which can be seen to-day in the naval ports of the nations +of the world. + +We might have had these submarines long ago but for the fact that the +men who were trying to invent them would not give up the secrets which +they had discovered. Many men in different parts of the world worked on +this problem and each discovered one or more things which were valuable +in working out a solution, and if they had all gotten together and +compared notes between them they could have produced a submarine boat +almost as good as those we have to-day. + + +How Does the Submarine Get Down Under the Surface? + +The first essential in a vessel to enable it to navigate below the +surface of the water is that it be made sufficiently strong to +withstand the surrounding pressure of water, which increases at the +rate of .43 of a pound for each foot of submergence. + +A boat navigating at a depth of 100 feet would therefore have 43 pounds +pressure per square inch of surface, or 6192 pounds for every square +foot of surface. It will readily be seen, therefore, that the first +essential is great strength. Therefore, the submarine boats are usually +built circular in cross section with steel plating riveted to heavy +framing, as that is the best form to resist external pressure. These +boats are built for surface navigation as well, therefore they have a +certain amount of buoyancy when navigating on the surface, the same as +an ordinary surface vessel. When it is desired to submerge the vessel +this buoyancy must be destroyed, so that the vessel will sink under the +surface. + +Now, the submerged displacement of a submarine vessel is its total +volume, and, theoretically, a vessel may be put in equilibrium with the +water which it displaces by admitting water ballast into compartments +contained within the hull of the vessel, therefore, if a vessel whose +total displacement submerged was 100 tons, the vessel and contents must +weigh also 100 tons. If it weighed one ounce more than 100 tons it +would sink to the bottom. If it weighed one ounce less than 100 tons it +would float on the surface with a buoyancy of one ounce. If it weighed +exactly 100 tons it would be in what submarine designers specify as +being “in perfect equilibrium.” + +It is possible to give a vessel a slight negative buoyancy to cause +her to sink to, say, a depth of 50 feet and then pump out sufficient +water to give her a perfect equilibrium, and thus cause her to remain +at a fixed depth while at rest. In practice, however, this is seldom +done. Most submarine boats navigate under the water with a positive +buoyancy of from 200 to 1000 pounds and are either steered at the depth +desired by a horizontal rudder placed in the stern of the vessel, or +are held to the depth by hydroplanes, which hydroplanes correspond to +the fins of a fish. They are flat, plane surfaces, extending out from +either side of the vessel, and when the vessel has headway, if the +forward ends of these planes are inclined downward, the resistance of +the water acting upon the planes is sufficient to overcome the reserve +of buoyancy and holds the vessel to the desired depth. If the vessel’s +propeller is stopped, the boat, having positive buoyancy, will come to +the surface. + +By manipulating either the stern rudders or the hydroplanes, the vessel +may be readily caused to either come nearer to the surface or go to +a greater depth, as the change of angle will give a greater or less +downpull to overcome the reserve of buoyancy. + +The above description applies to navigating a vessel when between the +surface of the water and the bottom. + +Another type of vessel which is used for searching the bottom in +locating wrecks, obtaining pearls, sponges, or shellfish, is provided +with wheels. In this type of vessel the boat is given a slight negative +buoyancy, sufficient to keep it on the bottom, and it is then propelled +over the water bed on wheels, the same as an automobile is propelled +about the streets. This type of vessel is also provided with a diver’s +compartment, which is a compartment with a door opening outward from +the bottom. If the operators in the boat wish to inspect the bottom, +they go into this compartment and turn compressed air into the +compartment until the air pressure equals the water pressure outside +of the boat; i. e., if they were submerged at a depth of 100 feet they +would introduce an air pressure of 43 pounds per square inch into the +diving compartment. The door could then be opened and no water could +come into the compartment, as the diving compartment would be virtually +a diving bell. Divers can then readily leave the boat by putting on a +diving suit and stepping out upon the bottom. + +[Illustration: ONE OF THE FIRST PRACTICAL SUBMARINES + +“PROTECTOR.” BUILT 1901-1902, BRIDGEPORT, CONN. + +This was the pioneer Submarine Torpedo Boat of the level-keel type, and +was built in Bridgeport in 1901-1902. It was shipped to St. Petersburg, +Russia, during the Russian-Japanese war. From St. Petersburg it was +shipped to Vladivostok, 6000 miles across Siberia, special cars being +built for its transport.] + +[Illustration: This picture illustrates the same vessel, also at full +speed under engines, with the conning-tower entirely awash and with +the sighting-hood and the Omniscope alone above water. Notwithstanding +the limited areas exposed above the surface, still observation could +be had well-nigh continuously either through the dead-lights in the +sighting-hood or by means of the Omniscope. + +In neither condition is it necessary to have recourse to electrical +propulsion--the boats can still be safely and speedily driven as here +shown under their engines.] + +[Illustration: THE INSIDE OF A SUBMARINE + +THE “G-1” RECENTLY DELIVERED TO THE UNITED STATES GOVERNMENT. + +The largest, fastest submarine in the United States and the most +powerfully armed submarine torpedo boat in the world. + +In addition to the usual fixed torpedo tubes arranged in the bow of the +vessel, which requires the vessel herself to be trained, the (seal) +“G-1” carries four torpedo tubes on her deck which may be trained while +the vessel is submerged, in the same manner as a deck gun on a surface +vessel is trained, and thus fired to either broadside, which gives many +technical advantages.] + +[Illustration: The above view gives a general idea of the interior +of a submarine torpedo boat and the method of operation when running +entirely submerged with periscope only above the surface. + +The commanding officer is at the periscope in the conning tower +directing the course of the submarine through the periscope, which +is a tube arranged with lenses and prisms which gives a view of the +horizon and everything above the surface of the water, the same as if +the observer in the submarine was himself above water. The steersman is +shown just forward of the commanding officer and steers the vessel by +compass under the direction of the commanding officer, the same as when +navigating above the surface. In the larger type boats the steersman +also has a periscope which enables him to see what is going on above +the surface. Below decks two of the crew are shown loading a torpedo +into the torpedo tube; each torpedo is charged with gun-cotton and +will run under its own power over a mile and will explode on striking +the enemy. The crew live in the compartment aft of the torpedo room. +Aft of this is the engine room, in which are located powerful internal +combustion engines for running on the surface and electric motors for +running submerged. The electric motors are driven by storage batteries +located under the living quarters. Wheels are shown housed in the keel, +which may be lowered for navigating on the bottom in shallow water. +A diving compartment in the bow permits divers to leave the vessel +when on the bottom, to search for and cut or repair cables or to plant +mines.] + +[Illustration: A SUBMARINE SAILING CLOSE TO THE SURFACE + +A submarine running partly submerged with the conning tower hatch +open, showing the remarkable steadiness of this type of boat in +a semi-submerged condition, a thing no other craft could safely +accomplish.] + +[Illustration: Another submarine running entirely submerged, periscope +only showing. The flag is attached to top of periscope to show her +position in maneuvers when periscope goes entirely under water.] + +[Illustration: A PHOTOGRAPH TAKEN WITH THE PERISCOPE UNIVERSAL LENS.] + + +AN ALL-SEEING EYE FOR THE SUBMARINE + +Vision under water is limited to but a few yards at best, and hence +a submarine boat, when submerged, would be as blind as a ship in a +dense fog and would have to grope its way along guided only by chart +and compass, were it not for a device known as a periscope, that +reaches upward and projects out of the water, enabling the steersman +to view his surroundings from the surface. Of course the height of the +periscope limits the depth at which the craft may be safely sailed. Nor +can the periscope tube be extended indefinitely, because the submarine +must be capable of diving under a vessel when occasion demands. But +when operating just under the surface, where it can see without being +seen, the craft is in far greater danger of collision than vessels +on the surface, because it must depend upon its own alertness and +agility to keep out of the way of other boats. The latter can hardly be +expected to notice the inconspicuous periscope tube projecting from the +water in time to turn their great bulks out of the danger course. + +The foregoing article describes the type of periscope now in common +use on submarines and one of the engravings on this page clearly +illustrates the principles of the instrument. A serious defect of this +type of instrument is that the field of vision is too limited. The man +at the wheel is able to see under normal conditions only that which +lies immediately before the boat. It is true that he can turn the +periscope about so as to look in other directions, but this, of course, +involves considerable inconvenience. On at least two occasions has a +submarine boat been run down by a vessel coming up behind it. + +[Illustration] + +~SEEING IN ALL DIRECTIONS AT ONCE~ + +As long as the submarine has but a single eye it would seem quite +essential to make this eye all-seeing; and since the two lamentable +accidents just referred to, an inventor in England has devised a +periscope which provides a view in all directions at the same time. +This has been attempted before, but it has been found very difficult +to obtain an annular lens mirror which would project the image down +the periscope tube without distortion. The accompanying illustrations +show how this difficulty has now been overcome. While we will not +attempt to enter into a mathematical explanation of the precise form +of the mirror lens, it will suffice to state that it is an annular +prism. The prism is a zonal section of a sphere with a conoidal central +opening and a slightly concave base. All the surfaces, however, are +generated by arcs of circles owing to the mechanical inconvenience +of producing truly hyperboloidal surfaces. The lens mirror is shown +in section at _A_ in Fig. 1. The arrows indicate roughly the course +of the rays into the lens and their reflection from the surface _B_, +which is preferably silvered. The tube is provided with two objectives +_C_ and _D_ (Fig. 3) between which a condenser _E_ is interposed at +the image plane of the lens _C_. At the bottom of the periscope tube +the rays are reflected by means of a prism _F_ into the eyepiece. Two +eyepieces are employed. One of lower power, _G_, is a Kelner eyepiece, +the purpose of which is to permit inspection of the whole image, while +a high-powered eccentrically placed Huyghenian eyepiece, _H_, enables +one to inspect portions of the image. The two eyepieces are mounted in +a rectilinear chamber, _I_, which may be rotated about the prism at +the end of the periscope, thus bringing one or other of the eyepieces +into active position. The plan view, Fig. 4, shows in full lines the +high-powered eyepiece in operative position, while the dotted lines +indicate the parts moved about to bring the low-powered eyepiece into +use. A small catch, _J_, shown in Fig. 2, serves to hold the chamber in +either of these two positions. The high-powered eyepiece is mounted on +a plate, _K_, which may be rotated to bring the eyepiece into position +for inspecting any desired portions of the annular image. The parts +are so arranged that when the eyepiece is in its uppermost position, +as indicated by full lines in Fig. 2, the observer can see that which +is directly in front of the submarine, and when the eyepiece is in its +low position, as indicated by dotted lines, he sees objects to the +rear of the submarine. With the eyepiece at the right or at the left +he sees objects at the right or left, respectively, of the submarine. +The high-powered eyepiece is slightly inclined, so that the image may +be viewed normally and to equal advantage in all parts. Mounted above +a plain unsilvered portion of the mirror is a scale of degrees which +appears just outside of the annular image. A scale is also engraved on +the plate _K_ with a fixed pointer on the chamber, making it possible +to locate the position of any object and rotate the plate _K_ so as +to bring the eyepiece _H_ on it. The scale also makes it possible to +locate the object with respect to the boat. + +[Illustration: HOW WE LOOK THROUGH A PERISCOPE + +THE PERISCOPE TOP.] + +[Illustration: PERISCOPE IN GENERAL USE.] + +[Illustration: THE UNIVERSAL OBSERVATION LENS.] + +This improved periscope is applicable not only to submarine boats but +for other purposes as well, such as photographic land surface work, in +which the entire surroundings may be recorded in a single photograph. +The accompanying photograph, taken through a periscope of this type, +shows the advantages of this arrangement and gives an idea of its value +to the submarine observer when using the low-powered eyepiece. Of +course, by using the other eyepiece any particular part of the view may +be enlarged and examined in detail. + +[Illustration: INSIDE OF A MINE-PLANTING SUBMARINE + +MINE-PLANTING SUBMERSIBLE. + +A Lake type vessel designed for planting contact mines. In naval +warfare it is sometimes of advantage to plant mines, either to defend +harbors, or in some cases the mines are planted in the course of the +approaching enemy. This is a vessel designed for that purpose. The +enemy is seen approaching, and the mine-planting submarine runs in +ahead of them in a submerged condition and drops a number of contact +mines on their course; the enemy strikes the mine and is blown up. A +number of vessels were blown up by contact mines of this type in the +Russian-Japanese war.] + + +Accidents and Their Causes. + +The accidents which submarine vessels must guard against are as +follows: collision, foundering, explosions and asphyxiation. The +first danger is, however, no greater than those to which vessels that +run entirely on the surface of the water are exposed. The eye of the +submarine places the commander on a practical level with the commander +of other vessels, so that if a collision occurs it is due to the same +lack of watchfulness which causes collisions on the surface of the +water. + +The submarine boat is less liable to founder than an ordinary vessel, +because she is built to withstand a greater pressure of water than +other kinds of vessels. Of course, if a submarine springs a leak, she +is in grave danger of sinking to the bottom, and there is less chance +of the crew being rescued from a submarine, because no one but those on +board know of the danger if the boat is under the water. + + +How Explosions May Occur. + +In submarine vessels explosions may occur either through a collection +of gases from the batteries or by reason of leaks in the pipes or +tanks of the fuel supply system, or through the bursting of the air +flasks belonging to the boat, or the air reservoirs in the automobile +torpedoes. The greatest danger is from explosive gases and have been +the cause of all explosions in modern submarine craft, and the greatest +danger in this connection is the liability of a leak in the gasolene +pipes or tanks. This gas is a heavy gas and so goes to the bottom of +the vessel, where it is not so easily detected as a gas which rises. +There is no certain way of guarding against leaks of gasolene. A leak +may occur at any time in a pipe or tank of gasolene through some cause +or other no matter how carefully inspected, and the gas from this is +so active that it will go through the tiniest hole imaginable--even +through a hole which water will not penetrate. The crew of a submarine +is always subject to this danger unless the tanks are built outside the +hull of the ship. + + +How the Air May Become Poisoned. + +There is a constant danger of asphyxiation to the men in the submarine. +A very small leakage of gas or the exhaust from an internal combustion +engine may make the air so impure that those aboard will be overcome. A +great deal of care must be taken to keep the air pure and to warn the +crew at the first sign of danger from this. + +When submarines first came into practical use, it was found a good idea +to take a number of little white mice down with the vessel to warn all +if the air began to become impure. As soon as this occurred, the mice +became distressed and squealed as loudly as they could, thus warning +those aboard the ship of danger. The mice felt the impurity of the air +quicker than the men, not because they had any special gift to discover +when the air was bad, but because they breathe much more quickly than +man--take shorter and many more breaths. + +Now, however, a chemical device has been invented which is affected in +such a way as to ring a loud bell, if the air in the vessel becomes +impure to such an extent that there is any danger. + +Breathing the same air over and over may fill the vessel with carbonic +acid gas. There should be no great danger from this, however, as +submarines are now built sufficiently large to provide enough actually +pure air for each man aboard for forty-eight hours, and it is hardly +conceivable that a submarine need be submerged more than half that +length of time under any conditions. + +Of course, then, too, there is the danger of accident due to +carelessness or ignorance. In other words, it is just as difficult to +make a fool-proof submarine as a fool-proof anything else. Wherever +anything is constantly dependent upon the continuous careful attention +of human beings, there is constant danger of accident, whether it be on +board a submarine, a railroad train, steamship or in connection with +anything else. + +[Illustration: A SUBMARINE UNDER THE ICE + +UNDER-ICE SUBMARINE TORPEDO BOAT. + +Submarine designed to navigate submerged under the ice, in ice-bound +countries. Vessels of this type could enter harbors and destroy the +enemy’s shipping at will. A vessel of this type would also be of value +in transporting mails, passengers and cargoes between ice-bound ports +where navigation by surface vessels is closed for several months in the +year.] + + +Story of How the Submarine Has Been Developed. + +It is only within the past twenty years that man has been able to +successfully navigate under the surface of the water. + +~WHO MADE THE FIRST SUBMARINE BOAT?~ + +It has been a dream of inventors and engineers for the past three +hundred years. + +During the reign of King James I. a crude submarine vessel was built of +wood, and was designed to be propelled by oars extending out through +holes in the side of the vessel, the water being prevented from coming +in through the openings by goat skins tied about the oars and nailed +to the sides of the boat, which made a water-tight joint, but at the +same time gave flexibility to the oars, so that by feathering them on +the return stroke they could be manipulated to give head motion. Very +little, if any, success could have attended this effort. + +Nearly a hundred years later a man by the name of Day built a submarine +and made a wager that he could descend to 100 yards and remain there +24 hours. He built a boat and submerged it in a place where there was +a depth of 100 yards. He succeeded in remaining the 24 hours, and +according to latest advices is still there, as he never returned to the +surface. + +There is very little information as to the construction of these early +craft. The first really serious attempt at submarine navigation was +made by a Connecticut man, a Dr. David Bushnell, who lived at Saybrook +during the Revolutionary War. He built a small submarine vessel which +he called the “American Turtle,” and with it he expected to destroy the +British fleet, anchored off New York during its occupation by General +Washington and the Continental Army. + +Thatcher’s Military Journal gives a description of this vessel and +describes an attempt to sink the British frigate “Eagle” of 64 guns +by attaching a torpedo to the bottom of the ship by means of a screw +manipulated from the interior of this submarine vessel. + +A sergeant who operated the “Turtle” succeeded in getting under the +British vessel, but the screw which was to hold the torpedo in place +came in contact with an iron scrap, refused to enter, and the implement +of destruction floated down stream, where its clockwork mechanism +finally caused it to explode, throwing a column of water high in the +air and creating consternation among the shipping in the harbor. +Skippers were so badly frightened that they slipped their cables and +went down to Sandy Hook. General Washington complimented Dr. Bushnell +on having so nearly accomplished the destruction of the frigate. + +If the performance of Bushnell’s “Turtle” was such as described, it +seems strange that our new government did not immediately take up +his ideas and make an appropriation for further experiments in the +same line. When the attack was made on the “Eagle,” Dr. Bushnell’s +brother, who was to have manned the craft, was sick, and a sergeant who +undertook the task was not sufficiently acquainted with the operation +to succeed in attaching the torpedo to the bottom of the frigate. Had +he succeeded the “Eagle” would undoubtedly have been destroyed and the +event would have added the name of another “hero” to history and might +then have changed the entire art of naval warfare. Instead of Bushnell +being encouraged in his plans, however, they were bitterly opposed by +the naval authorities. His treatment was such as finally to compel him +to leave the country, but he returned after some years of wandering, +and under an assumed name, settled in Georgia, where he spent his +remaining days practicing his profession. + +Robert Fulton, the man whose genius made steam navigation a success, +was the next to turn his attention to submarine boats, and submarine +warfare by submerged mines. A large part of his life was devoted to +the solution of this problem. He went to France with his project and +interested Napoleon Bonaparte, who became his patron and who was the +means of securing sufficient funds to build a boat which was called +the “Nautilus.” With this vessel Fulton made numerous descents, and +it is reported that he covered 500 yards in a submerged run of seven +minutes. + +~HOW SUBMARINES WERE DEVELOPED~ + +In the spring of 1801 he took the “Nautilus” to Brest, and experimented +with her for some time. He and three companions descended in the harbor +to a depth of 25 feet and remained one hour, but he found the hull +would not stand the pressure of a greater depth. They were in total +darkness during the whole time, but afterward he fitted his craft with +a glass window 1¹⁄₂ inches in diameter, through which he could see to +count the minutes on his watch. He also discovered during his trials +that the mariner’s compass pointed equally as true under water as above +it. His experiments led him to believe that he could build a submarine +vessel with which he could swim under the surface and destroy any +man-of-war afloat. When he came before the French Admiralty, however, +he was met with blunt refusal, one bluff old French admiral saying: +“Thank God, France still fights her battles on the surface, not beneath +it,” a sentiment which apparently has changed since those days, as +France now has a large fleet of submarines. After several years of +unsuccessful efforts in France to get his plans adopted, Fulton finally +went over to England and interested William Pitt, then chancellor, +in his schemes. He built a boat there, and succeeded in attaching a +torpedo beneath a condemned brig provided for the purpose, blowing her +up in the presence of an immense throng. Pitt induced Fulton to sell +his boat to the English government and not bring it to the attention of +any other nation, thus recognizing the fact that if this type of vessel +should be made entirely successful, England would lose her supremacy as +the “Mistress of the Seas.” + +Fulton consented to do so, but would not pledge himself regarding his +own country, stating that if his country should become engaged in war, +no pledge could be given that would prevent him from offering his +services in any way which would be for its benefit. + +The English Government paid him $75,000 for this concession. Fulton +then returned to New York and built the “Clermont” and other +steamboats, but did not entirely give up his ideas of submarine +navigation, and at the time of his death was at work on plans for a +much larger boat. + +Fulton had a true conception of the result of submarine warfare, and in +a letter he says: “Gunpowder has within the last three hundred years +totally changed the art of war, and all my reflections have led me to +believe that this application of it will, in a few years, put a stop +to maritime wars, give that liberty on the seas which has been long +and anxiously desired by every good man, and secure to Americans that +liberty of commerce, tranquillity, and independence which will enable +citizens to apply their mental and corporeal facilities to useful and +humane pursuits, to the improvement of our country and the happiness of +the whole people.” + +After Fulton’s death spasmodic attempts were made by various inventors +looking to the solving of the difficult problem, but no very serious +efforts were put forth until the period of the Civil War, and then a +number of submarine boats were built by the Confederates. These boats +were commonly called “Davids,” and it was one of them that sank the +United States steamship “Housatonic” in Charleston Harbor on the night +of the 17th of February, 1864. This submarine vessel drowned four +different crews, a total of thirty men, during her brief career. At the +time she sank the “Housatonic” her attack was anticipated, and sharp +lookout was kept at all times; but, notwithstanding their vigilance, +she succeeded in getting sufficiently close to plant a torpedo on the +end of a spar, and sink this fine, new ship of 1400 tons displacement. + +It will be seen from the above description that these vessels, while +able to go under water, were not controllable. + +After the Civil War several other inventors took up the problem of +trying to design a submarine vessel that could be controlled as to +maintenance of depth and direction under water. + +In Europe, Gustave Zede, Goubet and Drzwiezki, and in this country Mr. +Baker and Mr. John P. Holland, built experimental vessels. + +In 1877 Mr. Holland built a small boat which was called the “Fenian +Ram.” It is stated that this vessel was built with capital furnished by +the “Clan-na-Gael,” with the idea of using it against the British fleet +in an attempt to free Ireland. + +While some slight success was met with by these inventors, it was not +until about 1897 that any real progress was made. + +~THE FIRST SUCCESSFUL SUBMARINE WITH HYDROPLANES~ + +In 1893, Simon Lake, an American inventor, submitted plans to the +United States Naval authorities at Washington for a submarine boat that +would navigate between the surface and the bottom by the use of what +he called “hydroplanes,” which were designed to cause the vessel to +submerge on an even keel. Mr. Lake’s design of vessel was also provided +with wheels to enable it to navigate on the water bed. It was also +provided with a diving compartment to enable the crew to don diving +suits and leave the vessel, in working on wrecks, cutting cables, +planting mines, etc. + +In 1904 and 1905 he built a small vessel to demonstrate his principles +and succeeded in successfully navigating the vessel on the bottom +of New York Bay. He then built a larger vessel of about 50 tons +displacement for further experimental purposes. This vessel was called +the “Argonaut,” and was built in Baltimore in 1906 and 1907. This boat +was successful from the start and covered thousands of miles in the +Chesapeake Bay and along the Atlantic Coast, New York Bay and Long +Island Sound, and was the first successful submarine boat to navigate +in the open sea and on the water bed of the ocean. + +Mr. Holland had, in 1894, received a contract for a submarine vessel +for the United States Navy, and her construction was started in 1895. +This vessel was called the “Plunger.” This was the first official +recognition given to a submarine boat in the United States. + +The Government of France had also given an order for a submarine boat +which was under construction at this period. + +The “Plunger” was never submerged, her construction covering a period +of several years, and she was finally abandoned. Mr. Holland had, +however, in the meantime prepared the designs of another vessel which +he called “The Holland.” This vessel was accepted by the United States +Government in 1900, and a number of other vessels of this type were +built. These vessels were known as submarines of the diving type. They +were controlled by means of a horizontal and vertical rudder placed at +the stern of the vessel and the boat was, by means of these rudders, +inclined down by the bow, and driven under the water by the force of +their screw propeller. + +England also built a number of submarines of the diving type. + +In 1901 Mr. Lake brought out a larger vessel of his type, which was +controlled by hydroplanes, which vessel was sold to the Russian +Government, was shipped across the Atlantic to Kronstadt, and from +there by rail to Vladivostok, and was in commission off Vladivostok +just before the close of the Russian-Japanese War. + +Mr. Lake then received orders from the Russian and other Governments +for a number of additional boats of the even keel type, to be +controlled by hydroplanes. + +Mr. Lake’s principles of control have been now generally adopted by all +Governments, as providing the safest and most reliable means of control +of the vessel when navigating under the surface. + +The United States Government has recently adopted this type to be +built in their Navy Yards, and most other builders have adopted the +hydroplanes as the means of maintaining depth when running beneath the +surface. + +[Illustration: CLEARING A CHANNEL OF BUOYANT MINES + +This is one of the services to which submarine boats of this type lend +themselves with peculiar fitness. It is possible for them to carry on +this work with deliberation and to success, under the very guns and +searchlights of a vigilant foe, without the slightest danger of being +detected. + +This would be accomplished preferably by the co-operation of two boats. +They would take opposite sides in the channel, with a connecting rope +extending out through the diving compartment. It is obvious that as +they move along the rope will sweep the whole mine-field and gather in +the connecting cables. This would be indicated at once to the operators +in the diving compartment by the load upon the sweeping line. A grapple +may then be attached to the rope and sent out of one boat and hauled +into the other, and thus drag the mine so near that a diver could go +out and destroy its electrical connections or cut it adrift. Should +the latter operation be the aim, the grapple may be so fashioned as +to accomplish this without the diver leaving the compartment. This +latter method is one strongly recommended by some of the most prominent +military authorities on submarine defense.] + +[Illustration: This picture indicates the manner in which the boats +have traveled many miles over all kinds of bottom. In the present +instance the boat is shown systematically searching the bottom with +her diving door open and strong lights being used to facilitate a more +perfect examination. + +There is no trim or equilibrium to maintain. When the propelling +machinery stops the boat comes to rest. A cyclometer attached to +these wheels gives a fairly reliable reading of the distance traveled +under normal circumstances. As the currents do not carry her out of +her course, and as her gauges give an absolute record of changing +depths, it is possible to so navigate upon the bottom with remarkable +precision. In shallow waters this method has many advantages.] + +[Illustration: A MACHINE WHICH MAKES THE DIVER’S TASK EASY + +SHOWING TUBE HANDLING CARGO IN SUNKEN SHIP.] + + +Recovering Cargo or Submerged Objects Without the Aid of Divers. + +The operating tube is here shown within the body of a hulk and +co-operating with the lifting derrick on the surface craft in the +removal of the submerged cargo. A grab-dredge bucket of well-known +construction is used, the jaws of which, when being lowered by one +rope, open, and when strain is brought on the lifting rope, the +jaws close. The working end of the tube is placed in the immediate +neighborhood of the cargo to be lifted and, as the grab is being +lowered from the boat above, the operator in the compartment controls +the grab by means of the guide line shown attached to the small derrick +boom, and leads it directly over the cargo to be lifted. The grab is +then dropped and the signal sent to the vessel above to hoist. The +moment the lifting line tautens the bucket grasps a load and fills +itself with material in the manner common to this type of dredge. This +method of directing intelligently and deliberately the dredge bucket +may be applied as well to the removal of rock or any other obstruction +or to any of those various services of kindred character familiar +to submarine engineers. The great and prime advantage of the system +is the fact that no divers are required, and the work is under the +perfect control of an operator subject only to atmospheric pressure. In +consequence, therefore, the only limit to the effective operating of +this apparatus is the length of the tube, and, as has been said, this +can be made long enough to reach depths denied to the diver simply by +interposing additional sections. + +[Illustration: LIFE ABOARD A SUBMARINE + +LIVING QUARTERS ABOARD A SUBMARINE.] + + + + +Where Do Sponges Come From? + + +Until within comparatively recent years, the sponge was regarded as +a plant; it is now known to belong to the animal kingdom, and to the +order spongida of the class of rhizopoda. Sponge is an elastic, porous +substance, formed of interlaced horny fibers, which produce by their +numerous inosculations, a rude sort of network, with meshes or pores +of unequal sizes, and usually of a square or angulated shape. Besides +these pores there are some circular holes of large size scattered +over the surface of most sponges, which lead into sinuous canals that +permeate their interior in every direction. The oscula, canals, and +pores, communicate freely together. The characteristic property of the +sponge is the facility with which it absorbs a large quantity of any +fluid, more especially of water, which is retained amid the meshes +until forced out again by a sufficient degree of compression, when the +sponge returns to its former bulk. From this peculiarity, combined with +its pleasant softness, arises the value of the sponge for the purposes +to which it is applied. In domestic economy and in surgical practice, +there is no other product that can be satisfactorily substituted for it. + +Sponge is an aquatic production, indigenous to almost every sea and +shore. It is abundant and varied between the tropics, but becomes +less so in temperate latitudes and continues to diminish in quantity, +variety, and size, as it is traced into European and colder seas, until +it almost disappears in the vicinity of the polar circles. Some sponges +are known to be hermaphrodite, but that the individual at one period +produces chiefly male elements, and later, chiefly female elements. +Fertilization takes place in the body of the mother, and the egg here +undergoes its early development. The embryo eventually bursts the +maternal tissue and, passing into one of the canals, is caught by the +current sweeping through the canal system and is discharged into the +surrounding water through one of the large apertures on the surface +of the sponge. In the Bahama Islands and along the coast of Florida, +the breeding time of many sponges covers the period from mid-summer on +through early Autumn. + +There is propagation sometimes by ciliated gemmules, yellowish and +oval, arising from the sarcode mass, and carried out by the currents. +These are mostly formed in the spring, and after swimming freely about +for a time, become fixed and grow. In its natural state, the sponge +is a very different looking object from the article of commerce. The +entire surface is covered with a thin, slimy skin, usually of a dark +color, and perforated to correspond with the apertures of the canals. +The sponge of commerce is in reality only the home or the skeleton of +the sponge. + +There are a few sponges that inhabit ponds and sluggish rivers; the +others are marine. Of these, many of the calcareous and siliceous kinds +inhabit the shores between tide-marks, preferring a site near the low +ebb, where, nevertheless, they are daily alternately submerged, and +left exposed to the atmosphere. The figured sponges with a fibrous +texture, to whatever genus they belong, are denizens of deeper water, +and are never left uncovered. They grow usually in groups, on rock +shells, shellfish, corallines, and seaweeds, and either have no power +of selection, or the quality of the site is indifferent to them. + + + + +How Do Sponges Grow? + + +In their growth, some sponges assume a determinate figure or at least +one whose variations are confined within certain limits. The greater +number are irregular and variable, their shape depending in a great +measure upon the peculiarities of their state, to which they easily +accommodate themselves. They will incrust a shell, or a crab, a rock, +or seaweed, following every projection and sinuosity. The offshoots +will spring up with a more luxuriant growth in the deeper sheltered +places until the original shape of the foundation they grow upon is +lost to sight. + +Sponges are unmoving and inirritable. They never remain rooted to the +places of the germination, and are incapable either of contracting or +dilating themselves or even of moving any fiber or portion of their +mass. The functions which distinguish them as living beings are few, +and faintly imaged. + + + + +How Do Sponges Eat? + + +Although sponges lack the power of motion possessed by most animals, +being nearly always attached, in one position or another, to some +object, the study of their habits in captivity brings out many of their +animal characteristics in a striking manner. Small specimens taken +from the sea and placed in dishes of salt water may be kept alive for +several hours if well cared for; and by using finely powdered coloring +matter, such as carmine or indigo, the manner of their feeding may be +readily observed. Sponges are more active in fresh sea water than in +stale; they cannot be kept alive out of water and soon die if exposed +to the air. Being unable to go in search of food, as a natural result, +they can grow only in places where there is always an abundance of +food suited to their wants. The great sponging grounds of the world +are wholly confined within waters having a relatively high temperature +during the entire year. The Old World sponges grow principally in +the Mediterranean and the Red seas; the New World sponges are found +about the Bahamas, southern and western Florida, and parts of the West +Indies. The finest sponges come from the East, but one of the American +species, the so-called “sheep’s wool,” stands high in favor. + +The commercial sponges are separated into six species, three of which +are European and three American. They are all referred to a single +genus called spongia, and though having much in common as regards +structure, their texture varies to such an extent as to make them of +very unequal value for domestic purposes. + +The Old World species may be arranged as follows, in order of their +grade of excellence, beginning with the best quality: The Turkey cup +sponge, Levant toilet sponge, the horse, honey comb, or bath sponge, +and the Zimoca sponge. The American species include the sheep’s wool +sponge, the yellow glove, violet, and grass, sponges. A very close +relationship exists between the species of the two continents. + +All known regions in which useful specimens abound contribute to the +world’s supply. The trade is extensive. The demands upon the fisheries +are great. In the Mediterranean, the fishing is carried on in some +places at a depth of forty fathoms. Divers, naked, or in armor, go down +to the bottom and tear off the sponges from their places of growth. In +some places drag dredges are employed. + + + + +How Are Sponges Caught? + + +In the past quarter-century the sponge-fishery of the Florida coast has +grown remarkably. Its headquarters is at Key West and several hundred +sailing vessels are engaged in the industry. The fishing appliances +consist of a small boat, a long hook, and a waterglass. The hook is +in reality a three-pronged spear attached to a pole thirty-five feet +long. In searching for sponge the fishers row about in the small +boat. By holding the glass on the surface of the water the bottom is +plainly seen and small objects are readily discerned. When a sponge is +sighted the pole with the hook attached is shot down and the product +deftly gathered. The boat-load is brought to the deck of the schooner, +allowed to remain there a few hours, and then is carried down into the +hold. On Friday nights, the fishing generally ends for the week, and +the vessel sails for some spot on the neighboring coast where there +are established crawls, or places for curing the catch. These crawls +are about 8 x 10 feet square, their purpose being to hold the sponges +while maceration and decomposition take place. The resulting refuse is +carried off by the tide. + +The fishermen go away for another catch and the sponges are left in the +crawls until the end of the following week when a new cargo is brought +in. The returning fishermen beat the decomposed sponges with clubs, +removing the impurities. The water is squeezed out, then the sponges +are allowed to dry on the ground. + +After drying, the hold of the large vessel is loaded to the utmost +with the product and the voyage to Key West is made. Buyers from New +York look over the sponges, and make offers for entire cargoes. The +fishermen dispose of their goods rapidly and sail away for more. The +buyers store the sponges in some dry building, and cause them to be +bleached by lime. A popular manner of bleaching is to wash the sponges +thoroughly in water, and then to immerse them in diluted hydrochloric +acid to dissolve any of the calcareous substance. Having again been +washed they are placed in another bath of dilute hydrochloric acid to +which six per cent. of hyposulphite of soda, dissolved in a little warm +water, has been added. In this bath the sponges remain for twenty-four +hours, or until the bleaching process is completed. After bleaching, +the sponges are pressed until their bulk is greatly reduced; they are +then baled, and shipped to New York, which is the distributing point +for the entire Florida product. + +Sponges are by far the most important fishery products of Florida, +representing about one-third of the annual value of the fishing +industry. In 1899, the yield was over 350,000 pounds of sponges of +which the first value was nearly $400,000. + + + + +Why Does Yeast Make Bread Rise? + + +There is a lot of sugar in the dough from which bread is made. Sugar +contains three things--carbon, hydrogen and oxygen. When sugar is +fermented it amounts practically to burning it. To make good bread +from the dough it is necessary to ferment the sugar which is in the +ingredients from which it is made. Yeast, which is a simple living +plant, has the power to ferment sugar. When sugar ferments, two things +are produced. One thing is the formation of carbonic acid gas. A great +deal of this carbonic acid gas is caught in the dough in the form of +large or small bubbles and some of it escapes into the air. The other +part tries to escape into the air also but cannot, and causes the dough +to rise, which makes the bread light, as we say. The holes you see in +the bread after it is baked are the little pockets where the carbonic +acid gas was retained in the dough. These bubbles of gas all through +the dough act like a lot of little balloons and lift the dough up with +themselves as they try to get to the top and escape into the air. + + + + +What Is Yeast? + + +Yeast is a living plant that is used for the purpose of causing +fermentation. The yeast we use in baking bread is an artificial +yeast--really a dough made of flour and a little common yeast and made +into small cakes and dried. If kept free from moisture it retains the +power of causing fermentation for some time. The flour and other matter +in a cake of yeast are only used to keep the yeast in a form where it +can be preserved. It is necessary to add water to start fermentation +and that is why we add hot water when we stir in the yeast for a baking. + + + + +Is a Moth Attracted By a Light? + + +It seems to be a strange contradiction of the nature of living things +that a moth should fly deliberately into a light or dash itself to +death against the glass surrounding a strong light. This is contrary +to the usual law of nature which gives the living thing an instinct to +protect itself against enemies. + +For a long time we thought that moths did not deliberately burn +themselves up by flying right into a light, but our naturalists +have proven that not only moths but certain birds, bees, flies and +butterflies, burn themselves up by flying into the flame of a light or +fire. + +[Illustration: HOW MAN LEARNED TO MAKE A FIRE + +SAWING + +This was probably man’s first method of producing fire. By rubbing two +sticks together in this way sufficient heat was produced to set fire to +easily burnable material such as dried grass, etc.] + +[Illustration: DRILLING + +An improvement came when man learned that by twirling a dry stick in +a hole in another piece of dry wood the fire could be started more +quickly.] + + + + +How Man Discovered Fire + + +Fire was probably one of man’s first, if not the first, great +discoveries, and has been one of his greatest servants as well as +one of his greatest dangers. We do not know who discovered fire, or +what nation first used it. It is, however, one of the signs that +distinguishes man from the other animals. Not any of the lower animals +was acquainted with the use of fire, while probably the earliest races +of mankind seem to have been acquainted with it. + +Mythology tells us wonderful stories of the origin of fire: according +to these tales it was stolen from the sun, or the gods, and given to +man; and Pandora, the first woman, was sent down to earth to punish man +for his theft. + +The most popular of these stories is the legend of Prometheus. +According to this legend, fire, in the early days, was under the +exclusive control of the gods. Prometheus, brother of Atlas, the god +who supported the world on his shoulders, determined that the use of +fire should be given to the people. He decided by some means to send +a spark of fire to the earth, believing that one spark caught by man +would start a burning flame that would never go out. + +With this idea in mind, Prometheus visited Zeus, the great ruler, to +carry out his purpose, for Zeus controlled fire. While Zeus was not +looking, Prometheus “stole some brands of fire from the hearth, which +he hid in the stalk of a fennel and sent it down to the earth.” Through +this Prometheus gave to man his first knowledge of fire. + +But while this story of fire may or may not be true, the use of fire +rests entirely with man and his ingenuity. Through his ingenuity man +was able to subject fire to his will; making it perform certain of his +labors; and to a certain extent making it his servant; although it +always did and always will get beyond his control at times. + +Our ancestors were not satisfied with preserving the fire which the +gods gave them; they tried and succeeded in producing it. One day one +of them discovered that by rubbing two sticks together rapidly, the +friction would create a fire. It was a most useful discovery. Before +long the whole of mankind had learned this trick; others improved on +this crude method until step by step men learned that by striking two +pieces of flint or other hard mineral together, quicker action was +obtained. + +[Illustration: DRILLING WITH BOW STRING + +Man’s ingenuity soon taught him that if he tied one end of a string to +something and wrapped it around his drilling stick, one end of which +was in a hole as in the first drilling picture, he could increase the +rapidity of making fire.] + +[Illustration: DRILLING WITH HELP + +With some other to hold the drilling stick while he operated the string +he was able to produce fire more quickly than he had ever done before.] + +All kinds of methods were devised to increase knowledge of producing +fire. The early Greeks found out how to catch the rays of the sun on a +burning-glass and produce fire; the Romans achieved the same results +through the use of mirrors. + +[Illustration: PLOWING + +This is another method man used for rubbing two pieces of wood +together. In following this plan he usually used one stick of bamboo +and rubbed it back and forth in a slot he had made in another piece of +bamboo.] + +[Illustration: FLINT AND PYRITES + +In some places it was discovered that if you struck a piece of hard +stone, like flint, against another, a spark was produced which could be +caught on a bunch of dry grass or moss and so start a fire.] + +In about A.D. 900, an Arab, named Bechel, discovered phosphorus, but it +took almost 800 years more for Haukwitz to learn that when phosphorus +was brought into friction with sulphur, fire would result. In another +hundred years the world was benefited by the invention of the friction +match--and since that time about one-half the people have been carrying +matches about with them, able thus to start a fire easily any time. + +~FIRE A MARK OF CIVILIZATION~ + +Fire and man’s knowledge of it have had much to do with man’s progress +in civilization. Before man had fire, his life and movements were much +like those of other animals. When man had learned to make a fire he was +free to move and live anywhere and, therefore, people began to cover +more territory. + +[Illustration: THE FLINT AND STEEL METHOD OF MAKING FIRE + +THE INTRODUCTION OF THE FLINT AND STEEL METHOD + +Because fire was so important to him, man kept on trying to make this +task easier. He finally contrived a tinder box when iron and steel +became known. The tinder box is where he kept his flint and the piece +of steel which he struck upon the flint. He also kept in the box pieces +of cloth or paper on which he caught the sparks so produced.] + +[Illustration: PISTOL TINDER BOX + +This is a picture of a tinder box in the form of a pistol. It enabled +man to produce sparks in greater numbers and more rapidly.] + +[Illustration: PRODUCING SPARK WITH FLINT AND STEEL + +This shows the method for striking the piece of steel against the flint +to make the sparks fall on the cloth or paper in the box.] + +[Illustration: A COMPLETE TINDER BOX SET + +This picture shows a very complete tinder box set used by the wealthy +people in the old days. A man carried this outfit with him just as +today he carries matches.] + +[Illustration: This tinder box set is very neat and compact. It is said +still to be used among the Himalayan tribes where it was discovered.] + +[Illustration: THE FIRST MATCHES + +THE OXYMURIATE MATCH + +This match, the first, was introduced in 1505. It was a slip of wood +tipped with a chemical mixture. To light it it was necessary to stick +its head into a bottle containing acid.] + +[Illustration: PROMETHEAN MATCH + +This was a paper cigarette dipped in a mixture of sugar and potash. +Rolled within the paper was a tiny glass bulb filled with sulphuric +acid. To light the match you pressed the bulb with pincers hard enough +to break the bulb. This released the acid which set fire to the paper.] + + +What Would We Do Without Matches? + +If one were to ask the man in the street what invention of the +nineteenth century is his most constant and invaluable ally he might be +mystified for the moment, but the undoubted answer would surely come +in the single word “Matches.” These familiar objects, apart from their +luxurious use by smokers, are the indispensable servants of mankind +from the moment of rising in the morning till the household is wrapped +in sleep, and it is to them we turn when disturbed in the hours of +darkness. + +[Illustration: FIRST LUCIFER MATCH + +Invented by John Walker in 1827. It consisted of a stick of wood tipped +with sulphur and then with a chlorate mixture. To ignite it the match +was drawn rapidly through a folded piece of sandpaper.] + +[Illustration: MODERN SAFETY MATCH + +The first practical match was made less than a century ago.] + +No doubt “familiarity breeds contempt,” and it is difficult to imagine +how man would fare, bereft of his box of matches. It might help the +world to realize how much it owes to the inventors of the Lucifer +Match, were it possible to cut off the supply of these magic fire +producers for only one brief day. It requires no very vivid imagination +to picture the consternation and confusion that such a step would +produce, and there is a grim humor in wondering how the primitive +methods of obtaining a light would serve the public convenience in +these days of strenuous hustle. + +Seeing that fire has been employed by man since prehistoric days, one +would expect that easy means of obtaining it would have been devised +in the early ages. We find, however, that until the beginning of the +nineteenth century nothing in the nature of a match was available, and +the crudest methods were still in use. We know from Virgil that in the +reign of the Emperor Titus fire was obtained by rubbing decayed wood +with a roll of sulphur between two stones, but it is not till Saxon +times that we have evidence of the use of the tinder box with its flint +and steel. That this latter was still regarded as something remarkable, +as late as the fifteenth century, is proved by its representation in +the collar of the Order of the Golden Fleece, which was founded in +1429. Burning glasses had, of course, been employed from the most +primitive times, but one can imagine the despair of an early Briton who +had to wait for a sunny day before he could boil his kettle. + +Incredible as it may seem, it was not a time well within the memory +of many people living to-day that matches in anything approaching +the form now familiar were offered to the public. The way for their +manufacture had been prepared by two discoveries; one by a German who +isolated phosphorus in 1669; the other by a Frenchman who produced +chlorate of potash in 1786. From this latter date the production of +fire was much facilitated, and a few years before Queen Victoria came +to the throne, John Walker--a chemist of Stockton-on-Tees--produced the +first friction matches of which there is any certain record. These, +called “Congreves,” were sold in boxes of fifty for 2/6, and their +success soon led others to experiment in match manufacture, so that +improvements were rapidly invented and factories sprang up in all parts +of the country. + +It would be a difficult task to compute accurately the value to the +human race of the introduction to general use of this little article. +At the present writing, in America the consumption of matches amounts +to over a billion of matches a day. + + +How Matches Are Made. + +To-day matches are in such demand that the ingenuity of man has devised +a machine which makes complete matches without the help of the human +hand. + +At the very start of operations a man feeds blocks of wood into the +jaws of the machine, and thenceforth the mechanical monster does its +own work. Seizing the block from the man’s hand, the machine grips it +between rollers and forces it against rows of keen-edged cutters, which +are so arranged that there is little or no waste. Each of these cutters +(and there are usually forty-eight in a machine) severs a piece of wood +of exact size and shape. At the same moment a plate rises from beneath, +which thrusts these little pieces of wood into a moving flexible +cast-iron band, or rather into small holes in this band, from which the +embryo matches project like bristles. This traveling band is about 700 +feet in length, and follows a serpentine course in its journey, which +occupies about an hour from start to finish, the speed being regulated +according to temperature so that the matches may be quite dry when they +reach the boxes. + +When the band arrives at the finishing point, a steel bar punches out +the matches stuck in its surface and they fall into the inside boxes +placed ready to catch them. These boxes are kept continually shaking, +to that no spaces are left and the matches fill them completely. As the +inside boxes fill, a steel arm presses them forward into their covers, +and they are passed along a trough in dozens, quickly wrapped in paper +and sealed by a machine. Quick-fingered girls then wrap twelve of these +dozen packages and we have the gross packages of boxes so familiar in +the stores. It will be seen, that in spite of the marvellous machines +which do so much, there is still plenty of work for human hands. + + +How Match Boxes Are Made. + +The machines for making the wooden box which contain the matches are +in themselves wonderful. First, a section of the trunk of an aspen +tree, about 30 inches in length, is made to revolve in what is known +as a peeling machine. After a few revolutions the rough outer surface +is removed, and thin rolls of smooth-surfaced wood are peeled off +or veneered. The machine at the same time scores the wood ready for +folding by the boxmaking machine. Cut into skillets, i. e., into pieces +of the size required for box covers or insides, the ends are next +dipped in pink dye to cover the edge of the wood which is not covered +by the label. The skillets then go to the box machines, which fold and +label them, and after half an hour in a cleverly devised drying chamber +they are ready for use. In one room alone sixty machines are labelling +and folding the skillets to the number of several thousand gross a day. +To see these machines take a strip of wood, push it forward to receive +the pasted label, fold it, fasten the joint, wipe off the superfluous +paste, and, finally, toss the finished “outside” into a receiving +basket, is as fascinating an example of mechanical ingenuity as the +industrial world can afford. + + +Are Matches Poisonous? + +A non-poisonous “strike anywhere” safety match, made from selected, +clear, strong cork pine is now made in this country, and is the first +satisfactory non-poisonous match. It is also the first match to be +endorsed by the country’s recognized leaders and authorities in fire +prevention and the conservation of human life and property. + +The Hughes-Esch Anti-White Phosphorus Match Bill, which became a +law during the administration of President Taft, was drafted by the +attorneys of the American Association of Labor Legislation, and is +the most drastic that our National Constitution will permit. It would +be unconstitutional to absolutely prohibit the manufacture of white +phosphorus matches, but the Hughes-Esch bill obtains the same result, +viz.: absolute prohibition by means of excessive taxation. No match +manufacturer in these days of keen competition can afford to pay a tax +of ten cents on each box of white phosphorus matches made, and place +his factory under government surveillance, for this tax of ten cents is +over three times as much as his present selling price to the wholesale +trade. + +As soon as man learned to make fire and light, he began to appreciate +how much more comfortable he could be if he could keep his lights +burning and to have his light independent of his fire, because it was +at times very uncomfortable to sit by a fire on a hot night simply +because he wished to use the light which it made. The first schemes +devised for lighting purposes merely were the camp-fire torch and the +rushlight. With these as a basis, man was enabled to fashion more +convenient forms of lighting. He invented the candle and the lamp, and +grown “enlightened,” boxed his light in iron and in other metals. + + + + +Did Candles Come Before Lamps? + + +The candle is in appearance a primitive affair, yet there is little +doubt that its predecessor was the lamp. Those old Egyptian tombs, +which have unlocked many mysteries, held lamps, and through them +evidence of ancient burial customs. Lamps played a part in the solemn +feasts of the Egyptians, who on such occasions placed them before their +houses, burning them throughout the night. Herodotus, in one of his +numerous references to Xerxes, alludes to the hour of lamp-lighting, +and evidences abound regarding the use of lamps among the ancient +Greeks. Lamps, indeed, are pictured upon some of their oldest vases, +indicating the symbolic significance which attached to them. + +[Illustration: A French watch tower of the fifteenth century in time +of siege. The tower is lighted by means of beacons and is protected by +dogs. Ruins of such a tower can still be seen at Godesberger on the +Rhine.] + + + + +What Were the Earliest Lamps? + + +It is probable that the earliest lamps were nothing more than +convenient vessels, filled with oil and fired by means of rushes. Among +the Romans pine splinters, the torch and the flambeau, supplied light +until the fifth century before Christ, and even when the Roman began to +use the lamp, it was by no means common, finding a place only in the +homes of the rich, or on special festival days. + +The custom of burning funeral lights beside the dead before interment +is a very old one. Gregory, interpreting its significance for the +Christian, says that departed souls, having walked here as the children +of light, now walk with God in the light of the living. The Roman, +Pliny, refers to the use of the pith of brittle rushes in making +funeral lights and watch-candles, which were probably the ancient +prototype of the old rushlight of England. Again, in speaking of flax, +Pliny states that the part of the reed that is nearest to the outer +skin is called tow, and is good for nothing but to make lamp-matches or +candlewicks. + + + + +What Were the Lamps of the Wise and Foolish Maidens Made Of? + + +When lamps had come into general favor, better attention was given +to their form and construction. The first seem to have been made of +baked clay, moulded by hand into elongated vessels to contain the oil, +and provided at one end with a lip to admit the wick. These are the +lamps which artists have pictured in the hands of the wise and foolish +virgins, though in the opinion of some scholars they were merely rods +of porcelain and iron, covered with cloth and steeped in oil. Another +early type, which was less common, presents a simple disc with an +aperture in the centre for the oil, and a hole for the wick, at one or +both of the sides. + +Under the Empire, when the light of the lamp had become general, the +better ones were made of bronze, ornamented with heads, animals, and +other decorations, attached to the handles, while as life in Rome +partook more of luxury and extravagance, gold, silver, or Corinthian +brass were the materials, the designs being more elaborate and +complicated. Many and beautiful examples of these ancient lamps have +been unearthed from the ruins of Herculaneum and Pompeii. + + + + +When Were Street Lamps First Used? + + +Dark must have been the lives of those people who, until comparatively +recent times, lived, in the absence of sunlight, by the feeble, +uncertain light of the primitive illuminants borne by these lamps. And +as for street lighting--that was a luxury but seldom indulged in, and +then, not for public benefit, but to enhance the glory of a potentate, +or grace the obsequies of some great man. Even Rome, at the height of +her luxury and beauty, rarely exhibited more than one or two lanterns +in her streets. These were suspended over the baths and places of +public resort. Occasionally, however, the streets were illuminated +during festivals and other public occasions, while the Forum was +sometimes lighted for a midnight exhibition. With these glittering +exceptions, and that memorable one when, to satisfy the homicidal +impulses of a bad emperor, the bodies of Christians were made living +torches, Rome was a city of darkness. + +[Illustration: THE FIRST STREET LIGHT IN AMERICA + +The first street light in America. Early in 1795 several large cressets +were placed on the corners of Boston’s most frequented street. +Pine-knots were placed in these fire baskets by the night watchman.] + + + + +When Were Candles Introduced? + + +Historical records indicate the prevalent use of candles in the +earliest days of Rome, but these candles were of the simplest +sort--mere string or rope which had been smeared with pitch or wax. +In the early Christian centuries it was the custom to dip rushes in +pitch and coat them with wax, a method of candle-making that was long +continued, for it was not until the fourteenth century that dipped +tallow candles were introduced. In the Middle Ages wax candles provided +the usual means of illumination, and these were made, not by common +craftsmen, but by monks, or by the servants of the rich. Until the +fifteenth century their use was confined to churches, monasteries and +the houses of nobles, but the demand for them had become so great that +the chandlers of London obtained an act of incorporation. As late as +the eighteenth century the candles were made by dipping the wicks +into melted wax or tallow, but about this time an ingenious Frenchman +conceived the idea of casting them in metal moulds. + +[Illustration: A part of the “Amende Honorable” of Jacques Coeur before +Charles VII of France.] + +[Illustration: A pagan votive lamp of bronze, now in the museum at +Naples.] + +It is only within a modern period that the state or city has assumed +responsibility in the matter of public lighting, which for the most +part had been left to the good will and public spirit of citizens. +But in England a proclamation was issued to the effect that every +individual should place a candle in each of the lower windows of his +house, and keep it burning from nightfall until midnight. + +[Illustration: THE FIRST OIL LANTERN + +The first “Réverbère”--oil lantern--with a metal reflector, used +to light the streets of Paris. It was invented by Bourgeois de +Châteaublanc in 1765, and used until the introduction of gas.] + +Paris was the first city to improve upon this method of street +lighting, and in 1658 huge, vase-like contrivances, filled with resin +and pitch, were set up in the principal thoroughfares. The improvement +proving, as may readily be seen, both dangerous and expensive, the +falct, so-called, were replaced by the lantern. This was at first +simply a rude frame, covered with horn or leather, within which a +candle burned. For more than one hundred years this was the extent of +the illumination which the authorities could provide. But of course +it was understood that no honest man would venture abroad without his +torch or flambeau, and as London, Berlin, Vienna, and all leading +cities of Europe, were in like case, the darkness of Paris could be +borne. + +[Illustration: Argand got his first suggestion for his burner--invented +in 1780--from this style of alcohol lamp, then in general use +throughout France.] + +But progress had been made, and early in the eighteenth century the +Corporation of London entered into contract with a certain individual +to set up public lights, giving him permission to exact a sum of six +shillings from every householder whose actual rent exceeded ten pounds. +In the middle of the same century the Lord Mayor and Common Council +applied to Parliament for power to light the streets of London better. +From the granting of this permission dates improvement in public +lighting. + + + + +Where Did the Word “Gas” Originate? + + +A Belgium chemist, Van Helmont, coined the word “gas” in the first half +of the seventeenth century. The Dutch word “geest,” signifying “ghost,” +suggested the term to him, and his superstitious neighbors hounded him +into obscurity for talking of ghosts. + +[Illustration: Hanging lamp from Nushagak in Southern Alaska. It is +suspended from the framework of the tent by cords. Oils and fats from +northern animals give a clear and steady light, and Eskimo lamps are +frequently praised by travelers.] + +[Illustration: WHAT THE BIG TANK NEAR THE GASWORKS IS FOR + +SIX MILLION CUBIC FOOT GAS HOLDER. + +Almost every boy and girl has seen the big tank near the gas works, and +most of them have wondered what was in it and what it is for. This big +tank is a “holder” in which the gas is stored after it is manufactured. + +The giant holders are reservoirs from which gas is constantly being +taken and the quantity on storage constantly replenished, as the +ordinary gas plant never ceases manufacturing its product. + +There is little or no danger of an interruption of the supply by reason +of accident, as gas plants are always equipped with duplicate apparatus +for emergencies.] + + +When Illuminating Gas Was Discovered. + +The first practical demonstration of the value of gas made from +coal for lighting was made by a Scotchman--Robert Murdock--who in +1797, after some years of experimenting, fitted up an apparatus in +the workshop of Boulton and Watt, in Birmingham, England, which +successfully lighted a portion of that establishment. The advantages +of this kind of lighting were so apparent that its use was rapidly +extended, although in many instances the people were afraid of it. For +a time this kind of lighting was confined to street lights. One of the +first great structures to be lighted by gas was Westminster Bridge in +London, and great crowds gathered to watch the burning jets nightly. It +was difficult to remove from the minds of the people the belief that +the gas-pipes were filled with fire and the jets were only openings +through which the flame in the pipes escaped. People sometimes touched +the pipes expecting to find them hot, and when the pipes were put in +buildings they made sure that they were placed several feet from the +walls lest the fire in them set fire to the buildings. + +The use of illuminating gas for lighting private houses developed quite +slowly because of this fear of the fire in the gas-pipes. This was not +entirely unwarranted, however, because at first the plumbers did not +know, as they do now, how to prevent leakage of gas from the pipes. +The methods of joining the pipes were oftentimes imperfect and, not +realizing the dangers which would follow leaks, causing explosions, the +workmen were often careless in installing the pipes. + +The first American house in which gas was used for lighting was the +home of David Mellville at Newport, R. I. Baltimore, Maryland, was the +first American city to use gas for lighting. It was introduced there in +1817. + + +How Does Gas Get Into the Gas Jet? + +If you hold a cool drinking glass over a burning gas jet for a moment, +a film of moisture will form on the inside of the glass and remain +until the tumbler becomes warm, and then disappear. Now, then, you will +remember that water is a mixture of oxygen and hydrogen, and that when +hydrogen is burned in the air, water is formed. It is also true that +whenever water is formed by burning anything, hydrogen is present in +it. You see, therefore, that the gas used for lighting purposes must +contain hydrogen. + +Let us now learn something more about what gas is made of. Wet a piece +of glass with a little fresh lime water and hold this over the lighted +gas jet. In a few moments a change takes place in the water. The water +turns somewhat milky. This indicates the presence of carbonic acid gas, +and the formation of carbonic acid gas, when burning is going on, means +the presence of carbon. + +From these two experiments we gather that the gas in the jet contains +hydrogen and carbon. All kinds of illuminating gas contain these two +substances. Sometimes there are small quantities of other substances +present, but the value of gas for lighting depends on hydrogen and +carbon. + +We have already learned about hydrogen, but it would be well to +re-learn about carbon. + +Carbon is an element, and an extremely important one, for a large part +of the composition of every living thing is carbon. It is found in +more compounds than any other element. Almost pure carbon can easily +be obtained by heating a piece of wood, in a covered utensil, until it +is turned into charcoal. Charcoal, which is black, is composed almost +entirely of carbon. It is a very interesting product in all ways; in +connection with gas we are particularly interested in the fact that +carbon will burn when heated in the air or in oxygen. + +Charcoal is very much like hard coal, both being formed in practically +the same way. Ages of years ago many large forests of trees were buried +under a layer of soil and rocks, during changes that occurred in the +earth’s surface, and the hot inside earth slowly heated the wood, until +almost nothing was left but the carbon. + +[Illustration: WHERE THE GAS IS TAKEN FROM THE COAL + +GENERATOR HOUSE AND 175-FT. STACK. + +In the process of gas making, coal is placed in the generator and +heated to an incandescent state, then from the top or bottom steam is +admitted and forced through the heated coal, producing a crude water +gas which is passed on to the carbureter. In this shell enriching oil +is produced, but as the oil and the water gas do not effectually unite, +they are passed on to the superheater, where, as its name implies, they +are subjected to a high temperature which thoroughly gasifies them into +a permanent gas.] + +[Illustration: AN INTERIOR VIEW OF GENERATOR HOUSE.] + +* Pictures on Gas Manufacture by courtesy of the Consolidated Gas, +Electric Light and Power Co. of Baltimore. + +[Illustration: ILLUMINATING GAS MUST BE SCRUBBED + +SHAVING SCRUBBERS. + +After passing into the scrubbers the gas is cooled, passed into the +scrubbers, and by contact with wooden slat trays, made up like screens; +a large portion of the tar is removed from the gas, the tar passing off +to large receptacles.] + +Soft coal was formed in much the same manner, but the process was not +so completely finished. Mixed with the carbon in soft coal we find +quite a good deal of other substances, of which hydrogen forms the +principal part. This is what makes soft coal valuable in the making of +illuminating gas. + +When soft coal is heated in a closed receptacle a gas is formed which +will burn. To show this we have only to take an ordinary clay pipe, +put a little piece of coal in the bowl, close the top with wet clay, +and put the bowl part of the pipe in the fire. When it is quite hot, a +gas will be found coming out of the stem of the pipe, which will, when +lighted, burn. + + +The Story In a Gas Jet. + +~HOW ILLUMINATING GAS IS MADE~ + +Soft coal is heated in large tubes of fire clay called retorts, and the +gas that is formed is then collected in a large tank and sent through +pipes to our homes after being purified. The part of the coal that is +left consists largely of carbon and is what we call coke. + +While the gas that comes directly from coal will burn if lighted, it is +not a desirable gas to burn in our homes, because it contains a number +of substances that should be eliminated before it is used for lighting. + + +How the Gas Is Purified. + +From the clay retorts the gas passes through horizontal pipes +containing water. This cools it and takes out of it most of the tar +and water vapor that are driven off with the gas when formed. These +substances settle in the water. The gas then goes through a series +of curved pipes, which are air cooled. These pipes constitute what +is known as an atmospheric condenser. From these the gas goes into +a series of receptacles containing wooden slat trays, made up like +screens. These receptacles are called the scrubbers, and they take out +of the gas the last traces of tar and some of the other compounds found +present. The removal of the sulphur is very important, for burning +sulphur gives off a gas which is not only extremely impure to breathe, +but also injurious to the health. + +From the scrubbers the gas goes on through pipes to the purifiers--boxes +which contain wood shavings coated with iron rust upon which the sulphur +is deposited by chemical action. At the same time the lime absorbs a +small quantity of carbonic acid gas, which is formed with the other +gases. From the purifiers the gas passes into the great iron tanks, in +which it is stored until needed. + +The gas in the tanks consists chiefly of hydrogen, a number of +compounds of hydrogen and carbon, and a small amount of a compound +of carbon and oxygen containing less oxygen than carbonic acid gas, +known as carbon monoxide. The hydrogen and carbon monoxide burn with +a very pale flame, which gives but little light and much heat. The +light-giving quality of the gas is found in the compounds of carbon and +hydrogen. When these burn, the particles of carbon are heated white hot +and glow very brightly, making a luminous flame. + +There are, of course, some impurities in the purified gas. These are +compounds containing sulphur and ammonia. The quantities of these +substances, however, are so small that they are harmless; but the +compounds taken out in the process of purifying the gas are saved, as +considerable use is made of them. The water used for washing the gas is +heavily charged with ammonia and is, in fact, the chief source of the +ammonia sold by druggists. + +[Illustration: HOW THE IMPURITIES ARE TAKEN FROM THE GAS + +PURIFYING BOXES. + +The principal impurity to be removed is sulphur, and this is +accomplished by passing the gas through large iron rectangular boxes +filled with wood shavings coated with iron rust upon which the sulphur +is deposited by chemical action.] + +[Illustration: STATION METER HOUSE, SHOWING CONSTRUCTION OF TWO NEW +13-FT. METERS.] + +[Illustration: HOW THE METER MEASURES THE GAS + +Fig 1 + +Fig 3 + +Fig. 2. + +Fig 4 + +Gas first enters inlet pipe _A_ (Fig. 3) passing along _A1_ into +covered valve chamber _B_ up through orifice _O_. It then passes down +through two of the valve ports at the same time, ports _C_ and _D1_ +(Fig. 2). Before _C1_ (Fig. 3) has gotten to its extreme opening, the +valve on the opposite side has moved to allow gas to pass down port +_D_. On every quarter turn of tangent _P_, one port is opening to +receive gas which passes down through the valve ports into the chambers +below (see arrows on Fig. 2), which shows the gas passing into chamber +_F_. The pressure being greater on the outside of the diaphragm, forces +the diaphragm inward and expels the gas from the inside of _D2_ through +_D_ and passes over the cross-bar into the fork channel (see Fig. +1). On the other side gas is passing down through port _D1_ (Fig. 2) +entering diaphragm _D3_, the pressure being greater on the inside of +_D3_ therefore forces the diaphragm outward and expels the gas from +the outside of diaphragm _D3_; out through port _C1_ into fork channel +same as shown in (Fig. 1). All exhaust gas from the chambers below +is checked from entering the chamber _B_ by the slide valve _G_ and +_G1_ (Fig. 2). Instead of passing into chamber _B_ it passes over the +cross-bars between _D1E1_ and _C1E1_ into the fork channels, then to +outlet pipe _N_ (Fig. 3) to house pipe. + +NOTE: All gas registered must pass through outlet _N_.] + +In addition to coal gas made in the way just described, there is +another form of illuminating gas, in the manufacture of which coal is +indirectly employed. This gas, known as water gas, because it is formed +by the decomposition of water, is produced by passing steam over red +hot carbon, in the form of hard coal or coke. When this is done, the +hydrogen in the steam is set free and the oxygen combines chemically +with the carbon, to form the carbon monoxide, that was mentioned as +being present, in small proportions, in ordinary coal gas. This carbon +monoxide is poisonous, if much of it is breathed, and as it has no +odor it is difficult to detect when escaping. A number of deaths have +resulted from water gas for this reason, and in some states the laws +forbid its use for lighting purposes. + +When water gas is used it must be enriched with some other substances +before it will yield much light. You have already learned that neither +hydrogen nor carbon monoxide burns with a bright flame, and you will +see that water gas must have something added to it to fit it for +lighting purposes. The substance usually added is the vapor of some +light, volatile oil, like gasoline. This vapor is composed of compounds +of carbon and hydrogen, and when it is mixed with the water gas it +forms a gas that yields a very satisfactory light; and that may be +produced more cheaply than common coal gas. + +There remains one more form of illuminating gas which has been the +subject of much discussion in recent years, namely, acetylene. This is +a compound of carbon and hydrogen, in which there is twelve times as +much carbon as hydrogen. It has not been discovered recently, for it +was known early in the nineteenth century, but its possible use for +lighting purposes was not considered then. + +Attention was directed to it a few years ago by the discovery of a +substance called calcium carbide. This is a compound of carbon and the +metal calcium, formed by heating to a very high temperature a mixture +of coal and lime. It has the peculiar property of decomposing, when +treated with water. The calcium present combines with the oxygen and +half the hydrogen of the water, to form common slacked lime or calcium +hydrate, while the carbon and the remainder of the hydrogen combine to +form acetylene gas. + +The gas formed in this way needs no purifications before burning; it +can be produced in small generators, and the production can be checked +at any time. When burned in the proper form of burner it yields the +brightest of all gas flames. For these reasons it is adapted for use in +small villages and for lighting single houses. It is also frequently +used in magic lanterns, where a strong and steady light is necessary. +But the cost of producing acetylene in large quantities is greater than +that of coal gas, and it seems extremely unlikely that it will ever be +much used for lighting large cities and towns. + + + + +How the Light Gets Into the Electric Light Bulb. + + +The incandescent lamp was invented in 1879 and the patents were granted +to Thomas A. Edison. There were, however, a number of electrical men +who were working on the idea at this time who deserve a great deal of +credit for developing the lamp. + +The incandescent lamp, which is used chiefly for house lighting, +consists of a glass bulb from which the air has been exhausted by +pumps and chemical processes--in which there is a thin filament of +tungsten metal wound on what is called an arbor (as shown in Fig. 4). +This filament opposes high resistance to the passage of the current +of electricity, and, consequently, is heated to incandescence when +a current passes through it. The removal of the air from the bulb +prevents the tungsten metal from burning up, as it would do if oxygen +were present. + +The filaments of the first lamps were made of vegetable fibre. The next +development was the cellulose process, which is still used in carbon +and metallized lamps, although a number of processes are used now which +improve the filament considerably. + +The discovery that tungsten metal could be used in incandescent lamps +was made in 1906. The first tungsten lamp manufactured in America was +made in 1907. + +[Illustration: THE DEVELOPMENT OF INCANDESCENT LAMPS + +Edison’s first lamp with a filament of bamboo fibre.] + +[Illustration: The carbon lamp--the oldest form of incandescent lamp.] + +[Illustration: Standard Mazda lamp--the highest development of the +incandescent lamp.] + +[Illustration: The Tantalum lamp developed just before the Mazda lamp.] + +[Illustration: Improved Mazda lamp for lighting large areas--the most +efficient lamp ever made.] + +The filaments of the first tungsten lamps were composed of two or +three short pieces of wire. In 1910, however, a lamp with a continuous +tungsten filament was invented which increased the strength of the lamp +wonderfully. + +Mazda is a trade name given to all metal filament lamps made by the +prominent American lamp manufacturers. + +The reason that the Mazda lamp is so much more efficient than the +carbon filament lamp is because the tungsten filament can be burned at +a much higher temperature than the present carbon filament, without +seriously blackening the bulb. + + + + +How Does an Arc Light Burn? + + +In the arc light a current of electricity is made to leap across from +the tip of one rod of carbon to the tip of another that is held a short +distance from the first. In passing across the current does not follow +a straight path, but makes a curve, or arc, whence comes the name “arc +light.” + +In this form of light the carbons are not enclosed in a space from +which air is excluded, consequently there is some destruction of the +carbon. The light is due to the fact that the air between the tips of +the carbon rods opposes a high degree of resistance to the current, so +that the rods become intensely hot at their tips. The high degree of +heat causes a slow burning of the carbon at the tips, and the small +particles that burn are heated white hot before they are consumed, thus +producing light. + +In order to keep the light from an arc light uniform in strength, it is +necessary to keep the tips of the carbon rods always the same distance +apart. This is practically impossible, and, as a result, the arc light +does not produce light that is well adapted for reading or for other +purposes that require constant use of the eyes. The light produced by +the arc light is very powerful, however, and for that reason it is much +used for street lighting. + + + + +What Are X-Rays? + + +It was discovered by Professor Conrad Roentgen in 1895, that if a +current of electricity be passed through a certain form of glass +bulb, from which most of the air has been exhausted, a disturbance +is produced in the ether that bears some resemblance to light waves. +For want of a better name to give to a disturbance which was not well +understood, Roentgen called his discovery the X-Ray, but it is now +frequently called in his honor the Roentgen ray. The nature of this +disturbance is not yet known, but as it does not affect the eye it +is not light. These rays are produced with a glass vacuum tube and a +battery from which a current of electricity is sent through the tube. +The wires of the battery are connected with two electrodes, one of +which consists of a concave disk of aluminum, and the latter of a +flat disk of platinum. The X-rays are discharged in straight lines as +shown in the figure. The most striking properties of the X-ray is its +power to penetrate many substances that are impermeable to light. All +vegetable substances, and the flesh of animals, are penetrated by it +very readily. Glass, metals, bones, and mineral substances generally +are opaque to it. Consequently, when a limb, or even the body of an +animal, is exposed to X-rays they pass through the fleshy parts, +but are stopped by the bones. Certain substances have the property +of glowing, or becoming fluorescent, when exposed to the X-ray, and +when screens of paper are coated with these substances they form a +convenient means of detecting the presence of X-rays. By holding the +hand between a tube that is giving off X-rays and a screen of this +kind, the bones of the hand will be outlined in shadow on the screen, +and the rest of the surface will glow with a greenish light. If a +bullet or other piece of metal has become imbedded in the body, it may +easily be located, if it is not in a bone, and the extent of an injury +to a bone or a joint may be plainly shown. For this reason the X-ray is +now widely used by surgeons. + + + + +How Man Learned to Fight Fire. + + +When you see the modern fire engine racing through the streets, gongs +ringing, with the firemen hanging on and the police clearing the track, +you should remember that it has taken man a long time to learn as much +as he has about fighting fire. + +No sooner did man learn to make fire than he found it necessary to +learn how to put it out. + +The first fire apparatus of record is found in Rome. The Gauls burned +the city in 390 B. C., each citizen was ordered to keep in his house a +“machine for extinguishing fire.” This consisted of a syringe. + +The first record of an actual machine for putting out fire is by Hero +of Alexandria. This contrivance, a “siphon used in conflagrations,” was +used in Egypt about a hundred and fifty years before Christ. + +The first record of what we would call a fire department is also found +in Rome. A disastrous fire, occurring in the reign of Augustus called +his attention to the benefit of a regular fire brigade would bring. So +he organized a fire department. It consisted of seven companies of a +thousand men each. + +The first real fire engines were used in 1633 at a big fire on London +Bridge. The first fire hose was invented by the two Van der Heydes in +1672. One of the earliest engines used consisted of a tank drawn by two +horses, which threw a stream an inch in diameter to a height of eighty +feet. An improved engine was invented in 1721 by Newsham, of London, +and the first engine used in the United States was made by Newsham. The +first steam fire engine was invented by John Braithwaite, of London, in +1829. + +Fire alarms came into use in medieval times. It was the custom, in many +of the towns to have a watchman stationed on a high building whose duty +it was to look for fires. As soon as he saw one, he gave warning by +blowing a horn, firing a gun, or ringing a bell. + +The first London fire department consisted of ten men of each ward. + +The first municipal American fire department was created in Boston in +1678. The fire engine was a hand pump bought in England. + +The first leather fire hose was made in America in 1808 in +Philadelphia. Rubber hose was first made in England at about 1820. + + + + +How Did Man Learn to Cook His Food? + + +The primitive man lived on raw food--raw flesh, roots, fruits and nuts. +There must have been a time when he lived thus because there was a time +when he had no fires and no knowledge of how to make a fire. There are +no records, however, to show when man learned that cooked food was best. + +It must have come about almost simultaneously with his knowledge of +fire, for the art of cooking goes back to the first knowledge of fire. +We do not know either how man learned to make a fire. The earliest +nations of which we have any record seem to have been acquainted with +fire and certain methods for producing it. Not only one but all early +nations seem to have been possessed of this knowledge. Occasionally +travellers have reported that people have been found who were +unacquainted with either fire or cooking, but investigation has always +proven these reports unauthentic. Cookery has always been found in +practice where people knew about fire. + +It is strange how man has lost track of the beginning of his knowledge +of fire and cookery, because fire represents the beginning of man’s +culture and cookery goes hand in hand with it. + +There are many legendary accounts of how man learned the value of +cooked food, all of which are based upon the accidental burning or +roasting of animals or birds. Perhaps, therefore, Charles Lamb’s “Roast +Pig” story, which we read with much laughter in our school readers, was +quite accurate from a historical standpoint. According to the story +a man’s house burned and he cried more over the fate of his pet pig +than about the loss of his house. He kept his pig in the house you will +remember and as soon as the fire died away he rushed into the debris +to look for his pet pig, hoping still to rescue him. He found him in a +corner and made haste to pick him up and carry him into the open air. +But the poor pig had been roasted to a turn and was still hot. The +man’s fingers went right into the well done roast pig and were burned. +With a cry he withdrew his fingers and put them into his mouth to blow +on them and thus he secured his first taste of roast pig, which he +found so much to his taste that he repeated the operation of licking +his fingers. + +While this is but a story, it is quite likely historically correct as +to this discovery of the value of cooked food to some of the early +nations. No doubt Fire and Cookery were developed together. + +When man had learned to make fire, he found that it often got beyond +his control. Here and there he would set the woods on fire quite +without intention perhaps, but with damaging results. He would watch +the conflagration and, when it was passed, he would find the baked +bodies of deer or other animals which had been overcome by the fire +and learned that baked meats were good to the taste and more easily +digestible than raw meats. + + + + +Why Does a Sponge Hold Water? + + +A sponge will hold water because it has, on account of the plan on +which it is grown the power of capillary attraction. The sponge is made +up of little hair like tubes. If you take a glass tube, open at both +ends and immerse one end in a vessel of water, you will find that the +water will rise in the tube to a level higher than the surface of the +water in the vessel. The smaller the hole through the glass tube, the +higher the water will rise. This is caused by the cohesion of the water +against the inside surface of the hole in the tube and causes a pull +upward. The water is pulled up into the tube because the surface of the +tube has a greater cohesive attraction for the water than for the air +which was in it and the air is forced out partly. Some liquids, such +as mercury will not rise in the same way, but is depressed in a glass +tube, since it cannot adhere to glass. Mercury however will run or rise +in a tin tube, just as water in a glass tube, because it adheres to the +tin. + +Now a sponge is merely a lot of capillary tubes which have the same +power of pulling up the water as the glass tube. The tubes in a sponge +are so fine that the water will rise to the entire length of the tubes. +In addition, this adhesive quality of water to the inside of the tubes +in the sponge is so strong, that the sponge can be taken entirely out +of the water and the water will remain in it. + + + + +Why Is the Right Hand Stronger Than the Left? + + +The right hand is stronger than the left only in case you are +right-handed. If you have the habit of being left-handed, your left +hand becomes stronger. If you are truly ambidextrous, your strength +will be the same in both hands. + +We get our strength by moving the various parts of the body, i. e., by +using them. When a little baby stretches his arms and legs and kicks, +he is only exercising naturally, making the blood circulate. + +You can prove that the fact that your right hand is stronger than your +left because of the greater use or exercise you give it, by tying your +right arm close to your side and keeping it in that condition without +using it for several weeks. When you remove the bands which held it +tight, you will find your arm has lost its strength and that now your +left hand is stronger. If, however, you are left-handed and tie that +hand down for the same length of time, your right hand would be the +stronger. This shows that the strength we have in our arms and legs, +and other parts of the body, is developed by using them and giving them +rational exercise. Of course, it is possible to over-use a part of +the body, but you will notice that nature always gives us a warning by +making us tired before we come to the point where further use of that +particular part of the body would cause injury. + + + + +Why Do My Muscles Get Sore When I Play Ball In the Spring? + + +They do this because you have probably not been exercising the +particular muscles which you employ in throwing a ball enough in the +winter to keep you in good condition. Muscles which have been developed +through use or work need more work to keep them in condition. In a +sense certain of the muscles which you employ in playing ball have +been treated during the winter very much as if you had tied them down, +as we suggested you might do with your arm. You have not been using +them--they have not been doing enough work, and they begin to lose +their strength when for any period they have not been used enough. The +soreness that you feel is the natural condition that arises when you +begin to use a muscle that has been idle for some time. + + + + +Why Does a Barber’s Pole Have Stripes? + + +In early years the barber not only cut hair and shaved people, but he +was also a surgeon. He was a surgeon to the extent that he bled people. +In early times our knowledge of surgery was practically limited to +blood letting. A great many of the ailments were attributed to too much +blood in the body, and when anything got wrong with a man or woman, the +first thing they thought of was to reduce the amount of blood in the +body by taking some of it out. + +The town barber was the man who did this for people and his pole +represented the sign of his business. + +The round ball at the top which was generally gilded represents the +barbering end of the business. It stood for the brass basin which the +barber used to prepare lather for shaving customers. + +The pole itself represents the staff which people who were having blood +taken out of their bodies held during the operation. The two spiral +ribbons, one red and one white, which are painted spirally on the pole, +represented the bandages. The white one stood for the bandage which was +put on before the blood was taken out and the red one the bandage which +was used for binding up the wound when the operation was completed. + + + + +How Was the Flag Made? + + +The design of our flag was outlined in a congressional resolution +passed on June 14, 1777, which stated “that the flag of the thirteen +United States be thirteen alternate stripes red and white; that the +union be thirteen stars, white in a blue field, representing the new +constellation.” After Vermont and Kentucky had been admitted to the +Union, Congress made a decree in 1794 that after May 1, 1795, “the flag +of the United States be fifteen stripes alternate red and white and +that the Union be fifteen stars white on a blue field.” This made the +stars and stripes again equal and it was the plan to add a new stripe +and a new star for each new state admitted to the Union. Very soon, +however, it was realized that the flag would be too large if we kept on +adding one stripe for each new state admitted to the Union, so on April +4, 1818, Congress passed a resolution reducing the number of stripes to +thirteen once more to represent the original colonies, and to add only +a new star to the field when a new state was admitted to the Union. At +this time there were twenty states in the Union. Since that time none +of the flags of the United States have more than thirteen stripes while +a new star has been added for each state until now we have forty-eight +stars, representing the forty-eight states. + + + + +Why Are Some Guns Called Gatling Guns? + + +A gatling gun is a kind of gun invented by Richard Jordan Gatling +in 1861 and 1862 and so it receives its name from its inventor. The +original gatling gun had ten parallel barrels and was capable of firing +1,000 shots per minute when operated by hand power. It was discharged +by turning a crank and would shoot in proportion to the rapidity with +which the crank was turned. It was at first not a huge success but has +from time to time been improved so that the crank is now turned by +electric power and about fifteen hundred shots per minute can be fired +with it. + + + + +How Did Hobson’s Choice Originate? + + +As used today, this expression means a choice with only one thing to +choose. Tobias Hobson was a livery stable keeper at Cambridge, England, +during the reign of King Charles I. He kept a stable of forty horses +which he hired out by the hour or day, and was famous in his day so far +as a livery stable keeper could be. + +When you went to Hobson to hire a horse, you had the privilege of +looking over all the horses in the stable to decide which one you would +like to drive, but he always made you take the one in the stall nearest +the door. In this way all the horses in the stable were worked in turn +and while you might pretend to choose your own horse, you really had no +choice--you had to take the one nearest the door or none. As soon as a +horse was hired, the other horses in the stable were moved up, each one +to the stall next towards the door so there was always a horse in the +stall nearest the door. + + + + +Why Do They Call It a Honeymoon? + + +The word Honeymoon which is commonly used to describe the first +few weeks after marriage, has always meant the first month or moon +after marriage, but does not have any reference to the month or moon +excepting as that describes a certain period of time. + +The word originated in an old custom quite common among newly married +couples among the ancient Teutons of drinking a kind of wine made from +honey during the first thirty days after being married. + +In these days newly married couples generally take a trip away from +home for a short or longer period after their wedding day and this is +called the honeymoon whether it is but a few days or three months or +more. The custom of drinking wine made from honey has been abandoned so +that the word is now used in an entirely different sense than formerly. + + + + +Why Is a Horseshoe Said to Bring Good Luck? + + +The luck of the horseshoe comes from three lucky things always +connected with horseshoes. These consist of the following facts: It is +the shape of a crescent; it is a portion of a horse; it is made of iron. + +Each of these has from time immemorial been considered lucky. Anything +in the shape of a crescent was always considered a thing to bring luck. +From the earliest times, too, at least since the world knew something +of the qualities of iron, iron has been regarded as a thing to give +protection and incidentally that would involve good luck. And lastly +the horse, since the days of English mythology, has been regarded as +a luck animal. When, then, we had a combination of the three--the +crescent, the iron and the horse in one object, it became a true lucky +sign in the eyes of the people. + + + + +Some Wonders of the Human Body. + + +There are said to be more than two million little openings in the skins +of our bodies to serve as outlets for an equal number of sweat glands. +The body contains more than two hundred bones. It is said that as much +blood as is in the entire body passes through the heart every minute, +i.e., all the blood in the body goes in and out of the heart once every +minute. The lung capacity of the average person is about 325 cubic +inches. + +With every breath you inhale about two-thirds of a pint of fresh air +and exhale an equal amount if you breathe normally. + +The stomach of the average adult person has a capacity of about five +pints and manufactures about nine pounds of gastric juice daily. + +There are over five hundred muscles in the body all of which should be +exercised daily to keep you in the best condition. The average adult +human heart weighs from eight to twelve ounces and it beats about +100,000 times every twenty-four hours. The perspiration system in the +body has only very small ducts or pipes, but there are about nine miles +of them. The average person takes about one ton of food and drink each +year. We breathe about eighteen times a minute, which amounts to about +3,000 cubic feet an hour. + + + + +Where Did the Expression “Kick the Bucket” Originate? + + +The expression originally came from the method used in stringing a +hog after killing it. The pig after being slaughtered was hung by the +hind legs. A piece of bent wood was passed in behind the tendons of +each of the hind legs and the pig hung up by this stick of wood much +like we hang up clothes with a clothes hanger today. The piece of wood +was called a bucket. The “bucket” part of the expression does not, +therefore, refer to a bucket at all but to this bent piece of wood. All +are not agreed on this explanation, however, as it does not explain +where the “kick” comes in. Many investigators hold to the belief that +a man named Bolsover was the first to “kick the bucket” literally and +that the expression came from the manner of his death. He stood on a +pail or bucket while arranging to hang himself by tying a rope around +his neck and to a beam which he could not reach without standing on the +bucket. When ready he kicked the bucket out from under his feet and +so succeeded in carrying out his own wishes and in so doing coined a +famous expression which still means “to die.” + + + + +How Did the Word “News” Originate? + + +The word “News” which was created to describe what newspapers are +supposed to print, came from the four letters which have for ages +been used as abbreviations of the directions of the compass. In this +N stands for North, E for East, S for South and W for West, and in +illustrating the points of the compass the following diagram has long +been used: + + N + | + W--+--E + | + S + +The earliest newspapers always printed this sign on the front pages of +their papers in every issue. This was done to indicate that the paper +printed all the happenings from four quarters of the globe. + +Later on some enterprising newspaper man who may have forgotten the +original significance of the letter in the diagram, arranged the +letters N. E. W. S. in a straight line at the head of the paper and +that is how what we read in the papers came to be known as news. + +Almost one-half the whole number of newspapers published in the world +are published in the United States and Canada. + + + + +Who Made the First Umbrella? + + +No one knows who made the first umbrella but we know that Jonas Hanway +of London was the first man to carry one over his head to keep off the +rain. + +Umbrellas seem to have been known as far back as the days of Ninevah +and Persepolis, for representations of them appear frequently in the +sculptures of those early days. The women of ancient Rome and Greece +carried them but the men never did. + +Mr. Hanway is said to be the first man who walked in the streets of +London with an open umbrella over his head to keep off the rain. He is +said to have used it for thirty years before they came into general use +for this purpose. + +[Illustration: HOW MAN LEARNED TO TELL TIME + +The first picture shows what was probably man’s first method of telling +time. The principle was the same as that of the sun-dial. It provides +to-day an accurate method of telling time. + +Of course, man in the early days needed to find some other means of +noting the passing of time at night, for then the sun cast no shadow +for him. His ingenuity taught him to make a candle which was light and +dark in alternate rings, and as each section burned he made a mark to +record the passing of a certain length of time. Before candles were +invented he used a rope in which he tied knots at equal spaces apart +and which he burned as shown in the third picture.] + + + + +The Story in a Time Piece + + +What Is Time? + +Time, as a separate entity, has not yet been defined in language. +Definitions will be found to be merely explanations of the sense in +which we use the word in matters of practical life. No human being can +tell how long a minute is; only that it is longer than a second and +shorter than an hour. In some sense we can think of a longer or shorter +period of time, but this is merely comparative. The difference between +50 and 75 steps a minute in marching is clear to us, but note that we +introduce motion and space before we can get a conception of time as a +succession of events, but time, in itself, remains elusive. + +In time measures we strive for a uniform motion of something and this +implies equal spaces in equal times; so we here assume just what we +cannot explain, for space is as difficult to define as time. Time +cannot be “squared” or used as a multiplier or divisor. Only numbers +can be so used; so when we speak of “the square of the time” we mean +some number which we have arbitrarily assumed to represent it. This +becomes plain when we state that in calculations relating to pendulums, +for example, we may use seconds and inches--minutes and feet--or +seconds and meters--and the answer will come out right in the units +which we have assumed. Still more, numbers themselves have no meaning +till they are applied to something, and here we are applying them to +time, space and motion; so we are trying to explain three abstractions +by a fourth! But, happily, the results of these assumptions and +calculations are borne out in practical human life, and we are not +compelled to settle the deep question as to whether fundamental +knowledge is possible to the human mind. + + +What Was Man’s First Division of Time? + +Evidently, man began by considering the day as a unit and did not +include the night in his time-keeping for a long period. “And the +evening and the morning were the first day,” Gen. i, 5; “Evening and +morning and at noonday,” Ps. lv, 17, divides the day (“sun up”) in two +parts. “Fourth part of a day,” Neh. ix, 3, shows another advance. Then +comes, “are there not twelve hours in a day,” John xi, 9. The “eleventh +hour,” Matt. xx, 1 to 12, shows clearly that sunset was 12 o’clock. A +most remarkable feature of this 12-hour day, in the New Testament, is +that the writers generally speak of the third, sixth and ninth hours, +Acts ii, 15; iii, 1; x, 9. This is extremely interesting, as it shows +that the writers still thought in quarter days (Neh. ix, 3) and had +not yet acquired the 12-hour conception given to them by the Romans. +They thought in quarter days even when using the 12-hour numerals! +Note, further, that references are to “hours”; so it is evident that +in New Testament times they did not need smaller subdivisions. “About +the third hour” shows the mental attitude. That they had no conception +of our minutes, seconds and fifth-seconds becomes quite plain when +we notice that they jumped down from the hour to nowhere, in such +expressions as “in an instant--in the twinkling of an eye.” + +Before this the night had been divided into three watches (Judges vii, +19). Poetry to this day uses the “hours” and the “watches” as symbols. + +This twelve hours of daylight gave very variable hours in latitudes +some distance from the equator, being long in summer and short in +winter. The amount of human ingenuity expended on time measures so as +to divide the time from sunrise to sunset into twelve equal parts is +almost beyond belief. In Constantinople, to-day, this is used, but in a +rather imperfect manner, for the clocks are modern and run twenty-four +hours uniformly; so the best they can do is to set them to mark twelve +at sunset. This necessitates setting to the varying length of the days, +so that the clocks appear to be sometimes more and sometimes less +than six hours ahead of ours. A clock on the tower at the Sultan’s +private mosque gives the impression of being out of order and about six +hours ahead, but it is running correctly to their system. Hotels in +Constantinople often show two clocks, one of them to our twelve o’clock +noon system. Evidently the Jewish method of ending a day at sunset is +the same and explains the command, “let not the sun go down upon thy +wrath,” which we might read, “do not carry your anger over to another +day.” + +This simple line of steps in dividing the day and night is taken +principally from the Bible because every one can easily look up the +passages quoted and many more, while quotations from books not in +general use would not be so clear. + + +How Did Man Begin to Measure Time? + +Now, as to the methods of measuring time, we must use circumstantial +evidence for the prehistoric period. The rising and the going down of +the sun--the lengthening shadows, etc., must come first, and we are on +safe ground here, for savages still use primitive methods like setting +up a stick and marking its shadow so that a party trailing behind can +estimate the distance the leaders are ahead by the changed position of +the shadow. Men notice their shortening and lengthening shadows to this +day. When the shadow of a man shortens more and more slowly till it +appears to be fixed, the observer knows it is noon, and when it shows +the least observable lengthening then it is just past noon. Now, it is +a remarkable fact that this crude method of determining noon is just +the same as “taking the sun” to determine noon at sea. Noon is the time +at which the sun reaches his highest point on any given day. + +[Illustration: The Sun-dial is only an improvement on the stick which +cast a shadow which enabled man to tell the time of day at any hour. +The shadow moves around the dial, falling on the numbers on the circle.] + + +How Is the Time Calculated at Sea? + +At sea this is determined generally by a sextant, which simply measures +the angle between the horizon and the sun. The instrument is applied a +little before noon and the observer sees the sun creeping upward slower +and slower till a little tremor or hesitation appears, indicating that +the sun has reached his height--noon. Oh! you wish to know if the +observer is likely to make a mistake? Yes, and when accurate local time +is important, several officers on a large ship will take the meridian +passage at the same time and average their readings, so as to reduce +the “personal error.” All of which is merely a greater degree of +accuracy than that of the man who observes his shadow. + +The gradual development of the primitive shadow methods culminated in +the modern sun-dial. The “dial of Ahas” (Isa. xxxviii, 8), on which +the sun went back ten “degrees,” is often referred to, but in one of +the revised editions of the Bible the sun went back ten “steps.” This +becomes extremely interesting when we find that in India there still +remains an immense dial built with steps instead of hour lines. + +In a restored flower garden, within one of the large houses in the +ruins of Pompeii, may be seen a sun-dial of the Armillary type, +presumably in its original position. It looks as if the plane of the +equator and the position of the earth’s axis must have been known to +the maker. + +Both these dials were in use before the beginning of our era and were +covered by the great eruption of Vesuvius in 79 A.D., which destroyed +Pompeii and Herculaneum. + +~THREE GREAT STEPS IN MEASURING TIME~ + +Modern sun-dials differ only in being more accurately made and a few +“curiosity” dials added. The necessity for time during the night, as +man’s life became a little more complicated, necessitated the invention +of time machines. The “clepsydra,” or water-clock, was probably the +first. A French writer has dug up some old records putting it back +to Hoang-ti 2679 B.C., but it appears to have been certainly in use +in China in 1100 B.C., so we will be satisfied with that date. In +presenting a subject to the young student it is sometimes advisable to +use round numbers to give a simple comprehension and then leave him to +find the overlapping of dates and methods as he advances. Keeping this +in mind, the following table may be used to give an elementary hint of +the three great steps in time measuring. + +Shadow time, 2000 to 1000 B.C. + +Dials and water-clocks, 1000 B.C. to 1000 A.D. + +Clocks and watches, 1000 to 2000 A.D. + +Gear-wheel clocks and watches have here been pushed forward to 2000 +A.D., as they may last to that time, but no doubt we will supersede +them. At the present time science is just about ready to say that a +time measurer consisting of wheels and pinions--a driving power and a +regulator in the form of a pendulum or balance, is a clumsy contrivance +and that we ought to do better very soon. + +It is remarkable how few are aware that the simplest form of sun-dial +is the best, and that, as a regulator of our present clocks, it is +good within one or two minutes. No one need be without a “noon-mark” +sun-dial; that is, every one may have the best of all dials. Take a +post or any straight object standing “plumb,” or best of all the corner +of a building. In the case of the post, or tree trunk, a stone (shown +in solid black) may be set in the ground; but for the building a line +may often be cut across a flagstone of the footpath. Many methods may +be employed to get this noon mark, which is simply a north and south +line: Viewing the pole star, using a compass (if the local variation +is known) or the old method of finding the time at which the shadow of +a pole is shortest. But the best practical way in this day is to use a +watch set to local time and make the mark at 12 o’clock. + +[Illustration: + + Drawing by James Arthur. + +A form of Sun-dial that is as good to-day as any dial for determining +noon.] + +On four days of the year the sun is right and your mark may be set at +12 on these days, but you may use an almanac and look in the column +marked “mean time at noon” or “sun on meridian.” For example, suppose +on the bright day when you are ready to place your noon mark you read +in this column 11.50, then when your watch shows 11.50 make your noon +mark to the shadow and it will be right for all time to come. Owing +to the fact that there are not an even number of days in a year, it +follows that on any given yearly date at noon the earth is not at the +same place in its elliptical orbit, and the correction of this by the +leap years causes the equation table to vary in periods of four years. +The centennial leap years cause another variation of 400 years, etc., +but these variations are less than the error in reading a dial. + + +How Did Men Tell Time When the Sun Cast No Shadows? + +[Illustration: + + Photo by James Arthur. + +WATER CLOCKS FOR TELLING TIME + +This picture shows the hour-glass or sand-glass. It is really a type of +water-clock, being based on the same principle. The upper glass bulb +was filled with sand and this sand fell through a little hole between +the two bulbs. When the sand had all gone through, the glass was turned +upside down and the operation repeated. + +TIME-BOY OF INDIA.--WATER-CLOCK. + +The Water-clock consisted of a large vessel filled with water, on the +surface of which was placed a smaller vessel, really a gong, with a +hole in the bottom. The water gradually filled the smaller vessel, and +it sank. The Time-boy sat beside the Water-clock and as soon as the +vessel sank he fished it out, emptied it, struck the gong one or more +times and set it on the water again.] + +During the night and also in cloudy weather the sun-dial was useless, +and we read that the priests of the temples and monks of more modern +times “went out to observe the stars” to make a guess at the time +of night. The most prominent type after the shadow devices was the +“water-clock” or “clepsydra,” but many other methods were used, such as +candles, oil lamps, and in comparatively late times, the sand-glass. +The fundamental principle of all water-clocks is the escape of water +from a vessel through a small hole. It is evident that such a vessel +would empty itself each time it is filled in very nearly the same +time. The reverse of this has been used, as shown in the picture of +the Time-boy of India. He sat in front of a large vessel of water and +floated a bronze cup having a small hole in its bottom in this large +vessel, and as the water ran in through the hole the cup sank. The boy +then fished it up and struck one or more blows on it as a gong. This he +continued and a rude division of time was obtained--while the boy kept +awake! + +[Illustration: Drawing from description by James Arthur. + +The “Hon-woo-et-low,” Canton, China. Copper jars dropping water.] + +The most interesting of all water-clocks was undoubtedly the “copper +jars dropping water,” in Canton, China, where it can still be seen. +Referring to the picture herewith and reading the four Chinese +characters downwards the translation is “Canton City.” To the left and +still downwards, “Hon-woo-et-low,” which is, “Copper jars dropping +water.” Educated Chinamen inform me that it is over 3000 years old. +The little open building or tower in which it stands is higher than +surrounding buildings. It is, therefore, reasonably safe to state that +the Chinese had a weather and time station over 1000 years before our +era. + +[Illustration: + + Photo by James Arthur. + +TOWER OF THE WINDS. + +This tower is located at Athens, Greece. It was built about 50 B.C. +It is octagonal in shape and had at one time sun-dials on each of its +eight sides. On top was a bronze weather vane from which it derived its +name.] + +~A PRIMITIVE TWELVE-HOUR CLOCK~ + +It is a 12-hour clock, consisting of four copper jars partially built +in masonry forming a stair-like structure. Commencing at the top jar +each one drops into the next downward until the water reaches the solid +bottom jar. In this lowest one a float, “the bamboo stick,” is placed +and indicates the height of the water, and thus in a rude way gives the +time. It is said to be set morning and evening by dipping the water +from jar 4 to jar 1, so it runs 12 hours of our time. What are the +uses of jars 2 and 3, since the water simply enters them and drips out +again? No information could be obtained, but I venture an explanation +and hope the reader can do better, as we are all of a family and +there is no jealousy. When the top jar is filled for a 12-hour run +it would drip out too fast during the first six hours and too slow +during the second six hours, on account of the varying “head” of water. +Now, the spigot of jar 2 could be set so that it would gain water +during the first six hours, and lose during the second six hours, and +thus equalize a little by splitting the error of jar 1 in two parts. +Similarly, these two errors of jar 2 could be again split by jar 3 +making four small variations in lowest jar, instead of one large error +in the flow of jar 1. This could be extended to a greater number of +jars, another jar making eight smaller errors. + +The best thing the young student could do at this point would be to +grasp the remarkable fact that the clock is not an old machine, since +is covers only the comparatively short period from 1364 to the present +day. Compared with the period of man’s history and inventions it is +of yesterday. Strictly speaking, as we use the word clock, its age +from De Vick to the modern astronomical is only about 540 years. If we +take the year 1660, we find that it represents the center of modern +improvements in clocks, a few years before and after that date includes +the pendulum, the anchor and dead beat escapements, the minute and +second hands, the circular balance and the hair spring, along with +minor improvements. Since the end of that period, which we may make +1700, no fundamental invention has been added to clocks and watches. +This becomes impressive when we remember that the last 200 years have +produced more inventions than all previous known history--but only +minor improvements in clocks! The application of electricity for +winding, driving, or regulating clocks is not fundamental, for the +time-keeping is done by the master clock with its pendulum and wheels, +just as by any grandfather’s clock 200 years old. This broad survey of +time measuring does not permit us to go into minute mechanical details. + +[Illustration: THE FIRST MODERN CLOCK + + Drawing by James Arthur. + +Modern clocks commence with De Vick’s of 1364, which is the first +unquestioned clock consisting of toothed wheels and containing the +fundamental features of our present clocks. References are often quoted +back to about 1000 A.D., but the words translated “clocks” were used +for bells and dials at that date; so we are forced to consider the De +Vick clock as the first till more evidence is obtained. It has been +pointed out, however, that this clock could hardly have been invented +all at once; and therefore it is probable that many inventions leading +up to it have been lost to history. That part of a clock which does the +ticking is called the “escapement,” and the oldest form known is the +“Verge.”] + +~EARLIEST CLOCKS HAD NO DIALS OR HANDS~ + +Scattered references in old writings make it reasonably certain that +from about 1000 A.D. to 1300 A.D. bells were struck by machines +regulated with this verge escapement, thus showing that the striking +part of a clock is older than the clock itself. It seems strange to us +to say that many of the earlier clocks were strikers only, and had no +dials or hands, just as if you turned the face of your clock to the +wall and depended on the striking for the time. + +[Illustration: + + Photo by James Arthur. + +ENGLISH BLACKSMITH’S CLOCK.] + +A good idea of the old church clocks may be obtained from the picture +herewith. Tradition has followed it down as the “English Blacksmith’s +Clock.” It has the very earliest application of the pendulum. The +pendulum is less than 3 inches long and is hung on the verge, or pallet +axle, and beats 222 per minute. This clock may be safely put at 250 +years old, and contains nothing invented since that date. Wheels are +cast brass and all teeth laboriously filed out by hand. Pinions are +solid with the axles, or “staffs,” and also filed out by hand. It is +put together, generally by mortise, tenon and cotter, but it has four +original screws all made by hand with the file. How did he thread the +holes for these screws? Probably made a tap by hand as he made the +screws. But the most remarkable feature is the fact that no lathe was +used in forming any part--all staffs, pinions and pivots being filed by +hand. This is simply extraordinary when it is pointed out that a little +dead center lathe is the simplest machine in the world, and he could +have made one in less than a day and saved himself weeks of hard labor. +It is probable that he had great skill in hand work and that learning +to use a lathe would have been a great and tedious effort for him. So +we have a complete striking clock made by a man so poor that he had +only his anvil, hammer and file. The weights are hung on cords as thick +as an ordinary lead-pencil and pass over pulleys having spikes set +around them to prevent the cords from slipping. The weights descend 7 +feet in 12 hours, so they must be pulled up--not wound up--twice a day. +The single hour hand is a work of art and is cut through like lace. +Public clocks may still be seen in Europe with only one hand. Many have +been puzzled by finding that old, rudely made clocks often have fine +dials, but this is not remarkable when we state that art and engraving +had reached a high level before the days of clocks. + +[Illustration: THE LARGEST CLOCK IN THE WORLD + + Courtesy of Colgate and Company. + +THE HANDS OF THE LARGEST CLOCK IN THE WORLD--ON THE ROOF OF THE COLGATE +FACTORY. + +This big clock faces the giant office buildings of down-town New York. +Its dial is 38 feet in diameter and can be read easily at a distance +of three miles, so that passengers on the incoming liners pick out the +clock as one of their first sights of New York. + +The next largest clock (on the Metropolitan Tower) is 26¹⁄₂ feet in +diameter; the Westminster clock of London, 22¹⁄₂ feet. + +The great clock weighs approximately 6 tons. The minute hand, 20 feet +long, travels at its point 23 inches every minute; more than one-half +mile each day. + +The bed of this clock is 4 feet in length, the wheels and gears being +made of bronze and pinions of hardened steel. The time train occupies +about one-third of the bedplate, and has a main time wheel measuring +18¹⁄₃ inches in diameter. This train is equipped with Dennison’s double +three-legged gravity escapement, which was invented by Sir Edmund +Becket, chiefly for use on the famous Westminster clock, installed +in the Parliament Buildings, in London, England. The use of this +escapement is most advantageous for a gigantic clock of this kind as it +allows the impulse given the pendulum rod to be always constant, and +therefore does not permit any change of power or driving force of the +clock to affect its time-keeping qualities. + +It requires about 600 pounds of cast-iron to propel this time train, +and the clock is arranged to run eight days without winding. The +gravity arms of the escapement are fastened at a point very near the +suspension spring, and the arms are fitted with bronze roller beat pins. + +The dial contains 1134 square feet, or about one thirty-fifth of an +acre. The numerals consist of heavy black strokes, 5 feet 6 inches +long and 30 inches wide at the outer end, tapering to a point at the +inner end. The circumference of the dial is approximately 120 feet. The +distance from center to center of numerals is 10 feet, and the minute +spaces are 2 feet. + +The background on dial is painted white, and in the daytime the black +numerals show up distinctly. At night the numerals, or hour marks, +are designated by a row of incandescent bulbs placed in a trough 5 +inches wide and 5 inches deep. The hands at night are outlined with +incandescent electric lights, there being 27 lamps on the hour hand and +42 lamps on the minute hand.] + +[Illustration: THE MACHINERY WHICH RUNS A BIG CLOCK] + +This picture shows the machinery necessary to operate a large modern +tower clock. + +The mechanism is held in place and confined entirely within a cast-iron +structure which is firmly bolted to the floor. The wheels are composed +of bronze, the pinions of steel (hardened) and the gears are machine +cut. At the front of the clock is a small dial which enables one to +tell exactly the position of the hands on the outside dials, and there +is also a second hand to permit of very close regulation and adjustment. + +Three ways are provided for the regulation. First by a knurled screw +at the top of bed frame. Second by a revolving disc at the bottom of +the pendulum ball. Very often by either of these two methods it is +impossible to bring the clock to fractional seconds, and in order to +permit of a nicety of adjustment there is a cup fitted at the top of +the ball so that by inserting or taking out lead pellets, the rating +can be brought to absolute time. + +[Illustration: THE CLOCK IN INDEPENDENCE HALL + +INDEPENDENCE HALL, PHILADELPHIA] + +[Illustration: NEW YORK CITY HALL] + + + + +Where Does the Day Begin? + + +To understand this subject we must first appreciate that a day as we +think of it is a division of time made by man for the purpose of his +own reckoning. So far as the beginning of day is concerned, it begins +at a different place in the world every hour; yes, every minute and +every second in the day. As, however, the distance in feet where the +day begins from one minute to another is so short that we can hardly +notice it in such short measurements of time, we will look at the +answer to the question from hour to hour. When you understand the +subject from that point you can yourself see that the day actually +begins at a different point of the earth every minute and every second +of time. + + + + +How Much of the Earth Does the Sun Shine on at One Time? + + +The sun is shining on some part of the earth all the time and the +shining of the sun makes the difference between day and night. Wherever +the sun is shining it is day-time, and where the sun is not shining it +is night-time. + +To illustrate we will make use of an ordinary orange and a lighted gas +jet. Let us take a long hat-pin and stick it through the orange from +stem to stem. Now hold the orange by the ends of the hat-pin up before +the lighted gas jet. You will notice that one-half of the orange is +lighted, while the other half is dark. Of course, it is the half of the +orange away from the light that is dark. Now, revolve the orange slowly +on the hat-pin axis toward the light. When you have turned the orange +half way round the part that was formerly dark is now lighted up and +the other part is now dark. + +Now examine closely and you will see that just one-half of the orange +is lighted at one time and the other half is dark. You revolve the +orange in front of the light slowly and a portion of the surface of the +orange is always coming into the light, while a corresponding portion +of it on the opposite side is constantly going into the dark. In other +words, whatever the speed at which you revolve the orange toward the +light, one-half of it is always light and the other half is always dark. + +This is exactly what happens in the relation of the earth to the sun +every day. One-half of the earth, which is continually revolving on +its axis, is facing the sun, and is, therefore, in the daylight, while +the other half of the earth’s surface is in darkness, because the +light from the sun does not strike any portion of it. If the earth +did not revolve one-half of it would always be in day-time, while the +other half would be continually having night-time. As the earth is +always moving or revolving the half where it is day-time is constantly +changing, so that the day is beginning on one-half of the earth’s +surface every second of the day. Actually, of course, then, if you live +on the east side of town day begins with you a little sooner than with +your chum who lives on the west side of town. We have come to measure +the beginning of day as sunrise and the beginning of night as sunset, +wherever we happen to be. + +For convenience in setting clocks and in measuring time we do not take +into consideration these very slight differences in the rising and +setting of the sun, but set our clocks all alike in different parts +of the same town or city to avoid confusion. In fact, in order to +overcome the difficulties and confusions arising in reckoning the time +of the clock in different localities, and still keep the beginning of +what we call day-time constant with the hands of the clock, we have +agreed upon what we call standard time. We agreed upon this system +of fixing standard time because the actual sun time by which people +set their clocks up to a few years ago led to so many mistakes in +catching trains, keeping engagements and other misunderstandings where +the question of time was involved. Then when this system of standard +time was adopted the confusion became even worse, and the mistakes and +misses more numerous, because some people insisted on setting their +clocks to standard time and others insisted on sticking to the old sun +time schedule. So you could never tell by looking at the clock what +time it really was unless they put a sign on the clock saying what kind +of time they were going by. Finally, however, most of the people came +to appreciate that it would be a good idea to use one uniform system of +setting the clocks and of having them in harmony in a sense with the +other clocks in the world, and the adoption of the standard time plan +became universal. To make this system practical and effective, certain +points about equally distant from each other were selected, at which +point + + + + +Where Is the Hour Changed? + + +the hour would change for all points within that zone. Under this +system all timepieces in any one zone point to the same hour. So the +clock time changes only as you go east or west. All points on a north +and south line have the same time as the zone in which it is located. + +For convenience in adjusting the time in America the country was +divided into four east and west zones. The first zone takes in +everything on a straight north and south line east of Pittsburg, and is +called Eastern time. The second zone extends from Pittsburg to Chicago, +and is called Central time; the third zone extends from Chicago to +Denver, and is called Mountain time; while the fourth zone extends +from Denver to the Pacific Ocean. These selections were made because +the sun actually rises about one hour later in Pittsburg than in New +York; one hour later in Chicago than in Pittsburg; one hour later in +Denver than in Chicago, and one hour later on the Pacific Coast than in +Denver. Under this plan when it is nine o’clock in New York it is only +eight o’clock at Pittsburg and all points in the Central zone; seven +o’clock in all points in the Mountain zone; six o’clock in Denver and +five o’clock in San Francisco. As you keep travelling westward you drop +one hour of the clock time in every zone, and as under this system the +earth’s east to west distance is divided into twenty-four such zones, +if you went west entirely around the world you would lose a whole day +of clock time. + +If, however, you went around the world from west to east in the same +manner you would gain a whole day. + + + + +Where Does the Day Change? + + +This system of agreeing on fixed places where the hour changes made it +necessary to also fix a point where for the purposes of the calendar +the day also changes. This imaginary north and south line is fixed +upon at 180 degrees west longitude, which would cut the Pacific Ocean +in two. This line makes it possible for a person to travel all day +before approaching this line and then find himself after crossing it +travelling all the next day with the same name for the day of the week. +Thus he could spend all of Sunday travelling toward the International +Day Line, as this is called, and after crossing it spend another +Sunday, which would be the next day, going away from it. This would +give him the novel experience of having two Sundays on successive days. +The same thing would happen if he were travelling to the Day Line on +Monday, Tuesday, Wednesday, Thursday, Friday or Saturday. He would live +through two succeeding days of the same name in the same week, one +right after the other. This would be in going westward. + +If you were traveling eastward and crossed the International Day Line +on Sunday at midnight you would lose a day completely out of the week, +for when you woke up the next morning it would be Tuesday. + + + + +Why Do We Cook the Things We Eat? + + +We have several reasons for doing this. The first and most important +reason to us is that the application of heat to food makes it more +easy to digest. Other reasons are that when cooked our food is more +palatable; the process of cooking kills all microbes, which, if taken +into our bodies alive, would give us diseases, and also it is easier +for us to chew food that has been cooked. + +[Illustration: WONDERS PERFORMED BY ELECTRIC LIFT MAGNET + +This picture shows the construction of a successful electric lift +magnet. This device, by means of magnetic attraction, fastens itself +to practically all kinds of iron and steel without the aid of slings, +cables or chains.] + + + + +The Story in a Magnet + + +What Makes an Electro Magnet Lift Things? + +The working parts of an electric lift magnet are as follows: + +_A Shell._--This is a steel casting heavily ribbed on the top for +strength, and also to assist in radiating the heating effect from the +coil. + +It is usually made circular in shape, the outside rim forming one pole, +while the lug in the center forms the other. The coil fits in between +these poles, thus making a magnet similar to the ordinary horseshoe +type. + +_A Bottom Plate._--The under side of the magnet is closed by a very +tough and hard non-magnetic steel plate, in order to protect the coil. + +As well as being non-magnetic, this plate also has sufficient strength +to resist the severe wear to which a magnet is necessarily subjected. + +_A Terminal Box._--A one-piece heavily-constructed steel casting bolted +to the top of the shell, containing and protecting the brass sockets +into which the wires from the coil terminate, forms the Terminal Box. + +The sockets are made to receive plugs placed on the end of the +conductor wire, by which the magnet is connected with the generator. + +_A Coil._--This consists of a round insulated wire which is passed, +while being wound, through a cement-like substance, heavily coating +each individual strand. + +A low voltage of current is then passed through the coil, a sufficient +length of time, to thoroughly dry out and bake the coating. This +renders the magnet absolutely fireproof, eliminating all danger of +short circuiting of the coil. + +When finished it is well taped to protect the outside wire from +becoming chafed. + +The coil is made slightly smaller than the inside dimensions of the +shell and the remaining space is filled with an impregnating compound, +which hardens to the consistency of pitch. + +This renders the coil thoroughly waterproof; also forms a cushion to +prevent injury from the severe jars and shocks, received when dropping +a magnet on its load. + +_A Controller._--The rapidity with which it is necessary to turn +current on and off while operating a magnet, creates what is called a +“back kick.” Unless this is dissipated quickly it is very destructive +to the coil. + +A special controller dissipates this back kick through a set of +resistance coils placed in the controller. By means of an automatic +arrangement, connection with these coils is made instantly upon +breaking the current between the magnet and generator. + +A system of control used prevents undue heating of the coil. This +enables the magnet to lift as large a load after a long steady run as +at the start. + + + + +What Is a Lodestone? + + +A lodestone is a variety of the mineral named magnetite which is a +natural magnet. The name magnet comes from the name of the mineral +magnetite and this in turn derived its name from the fact that it was +first discovered in Magnesia. The word magnet really means the “Stone +of Magnesia.” + +A lodestone is one of the mysteries of nature. Its properties can +more nearly be understood if we examine an artificial magnet, which +is generally made in the form of either a straight bar or a shoe. +An artificial magnet is made of iron. If you drop a bar magnet into +a box of iron filings, the filings attach themselves to the bar. If +you examine it closely you observe that most of the filings attach +themselves to the ends of the bar. Therefore we call the ends of the +bar the poles of the magnet. + +If you suspend a magnetic needle at its center of gravity so that it +is absolutely free to turn, you will soon find one end of the needle +pointing north and the other south of course. The end which is pointed +toward the north is called the north pole and the other the south pole. +If you have a horse-shoe magnet, you can demonstrate this for yourself. +Rub the end of your magnet over a sewing needle and oil the needle so +that when you lay it on the surface of a glass of water it will float. +Then look at it closely. You will see the needle slowly turn until +finally it becomes quite still. If you have a compass at hand so that +you know surely which is north and which is south, you will find one +end of the needle pointing north and the other south. You can then +place the end of your magnet against the outside of the glass and draw +the needle toward your magnet. Your horse-shoe magnet has its north and +south poles close together. + +If you have a bar magnet and the end of the needle with the eye in it +is pointing north, you can drive the needle on the surface of the water +away from you by touching the outside of the glass opposite that end of +the needle with the north pole of your magnet. On the other hand, if +you reverse the experiment and place the south pole of your magnet to +the side of the glass, the needle will come toward the magnet. In other +words then the like poles of a magnet repel each other and the unlike +poles attract each other. + +Another interesting way to show this is to take two lodestones or two +magnets and let a lot of iron filings attach themselves to the ends +of them. Then when you have done this, point the two north poles of +the magnets or lodestones at each other close together. You will be +intensely interested in seeing how quickly the mysterious something +that is in the magnets makes the filings on the two ends of the magnet +try to get away from each other. On the other hand when you put a north +and south pole together, they form a union of the iron filings. + +Another strange thing about a magnet is that if you break it in two, +each half will be a complete magnet in itself with a north and south +pole also, and this is true no matter how many times you break it +into pieces. From this we learn that each tiny particle or molecule +throughout the bar is a magnet by itself. + +[Illustration: WHAT A LODESTONE IS + +This is a picture of a complete electro magnet. The magnet is attached +to the arm of a crane by the loop in the center and when the magnet +then comes in contact with any kind of iron or steel it lifts it as +soon as the current is turned on. By making the electric current +stronger, greater weight can be lifted. Many tons of material can be +lifted at one time. An electro magnet will do the work of many men at +much less cost.] + +[Illustration: In this picture we see the magnet lifting a great weight +of miscellaneous pieces of scrap iron. As many as twenty tons can be +lifted and transferred from one place to another at one time.] + +Some things can be magnetized while others cannot. Many substances have +not the property of magnetizing other substances when they have once +been attracted by a magnet. These are called magnetic substances. They +remain magnetized only as long as they are in touch with the magnet; +other substances when once magnetized become permanent magnets. Steel +and lodestone have this faculty. A compass needle is an artificial +magnet which becomes a permanent magnet when rubbed with a magnet. + + + + +What Is Electricity? + + +If you pass a hard rubber comb through your hair, in frosty weather, a +crackling sound is produced, and the individual hairs show a tendency +to stick to the comb. After being drawn through your hair a few times, +you may notice that the comb has become charged with electricity. This +electricity is produced by friction. Not only rubber but many other +substances become electrified by friction, such as a bar of sealing +wax rubbed with flannel, or a glass rod rubbed with silk, will show +the same qualities, and these simple experiments teach us many of the +fundamental facts about electricity. + +Some simple experiments will be found instructive and interesting. Rub +with flannel a stick of sealing wax until it is electrified and then +bring it close to a pith ball which should be hung by a silk thread. +The pith ball will at once be attracted to the sealing wax, and, if +brought quite close, the ball will adhere to the wax for a few moments, +and then fly away from it. The ball will now be repelled by the sealing +wax instead of being drawn toward it. Now take a glass rod, rub it with +a silk cloth after drying it thoroughly. When the pith ball is brought +close to the glass rod it also will at first be attracted toward the +glass and, if brought in contact with the glass, the pith ball will +adhere as before. It will also then fly away in the same way it did +from the sealing wax. Repeat these experiments with the sealing wax now +and you will find the ball will be attached, as it was at first, but if +it touches the wax it will again adhere for a moment and then fly away. +By using the sealing wax and glass rod alternately and bringing them +into contact with the pith ball, you discover that when it is attracted +by one, it is repelled by the other, and that, after it has been in +contact with either for a few moments it is no longer attracted by it. + +We learn thus that the electricity in the glass and the sealing wax +are not the same. To distinguish the two kinds of attraction, we say +the glass is charged with positive, or vitreous electricity, while the +charge on the sealing wax is called negative, or resinous electricity. + +When the pith ball was touched with the sealing wax, it became filled +with negative electricity, and was then no longer attracted by the +wax, but was repelled by it and attracted by the glass rod; but when +the ball had been filled with positive electricity, it was repelled by +the glass and attracted by the wax. We conclude from these facts that +bodies filled with the same kind of electricity repel each other, while +bodies filled with opposite kinds of electricity attract each other. + +When two substances are charged, as we say, with electricity of +opposite kinds and are brought into contact, and left so for some time, +the two charges disappear, one appearing to neutralize the other. From +this, we conclude, and rightly, that any substance not electrified, +contains equal amounts both positive and negative electricity. When, +therefore, we rub a piece of glass with silk, we are not creating +electricity, but only separating the different kinds. The positive +electricity adheres to the glass, and the negative remains behind, +on the silk. In the same manner, when we electrify sealing wax with +flannel the negative kind remains in the sealing wax and the flannel +becomes charged with the positive. Whenever a body is electrified by +friction, both kinds of electricity are produced; it is impossible to +produce one kind without the other. + +[Illustration: WHAT ELECTRICITY IS + +Magnets are particularly valuable in lifting raw material in a steel +mill. The red-hot pig-iron, from which steel is made, can be handled +easily in this way, whereas it would be impossible to handle same by +hand. Sometimes great quantities of iron are broken up by the magnet. A +weight of many tons is lifted by the magnet and allowed to fall on the +material to be broken up. The weight falls as soon as the current is +turned off.] + +[Illustration: + + Weight of wheel, 8160 lbs. + +Pieces of machinery which cannot be lifted by men on account of their +great weight and shape are handled easily.] + +You must rub the entire glass rod or bar of sealing wax to electrify +the whole of it. If only a part of the glass rod or sealing wax is +rubbed, only that part becomes electrified, as may be shown by trying +to attract a pith ball with the part that has not been rubbed. + +~WHAT GOOD AND BAD CONDUCTORS OF ELECTRICITY ARE~ + +If, however, the charged part of the sealing wax is brought into +contact with a metal rod resting on, say, a drinking glass, the rod +becomes charged, not only where it is brought into contact, but all +over its surface. Substances over which electricity flows readily +are called conductors of electricity. All metals are of this kind. +Things like glass and sealing wax over which electricity does not flow +readily, are called non-conductors, or insulators. Water, the human +body, and the earth are good conductors and rubber, porcelain, most +resins, and dry air are non-conductors. + +You have already learned that substances charged with opposite kinds of +electricity attract each other, and substances charged with the same +kind repel each other. We will try to discover why substances charged +with either kind of electricity attract small light objects, such as +pith balls, when these latter are not charged with electricity. As we +have discovered, all substances which have remained undisturbed have +both kinds of electricity present in them, in equal amounts. Now, when +an uncharged body is brought near a charged body, the two kinds of +electricity in the uncharged body have a tendency to separate. The kind +opposite in character, to that on the charged body, is attracted toward +the charged body, and the other kind is repelled. Thus, if our bar of +sealing wax, charged with, let us say, negative electricity, is brought +near a pith ball, the positive electricity in the ball is attracted +to the side nearest the scaling wax, and the negative electricity +is repelled to the farther side. As the positive electricity on the +pith is nearer to the scaling wax than the negative, its attraction +for the negative charge, on the sealing wax, is stronger than the +repulsion between the negative electricities of the two objects, and +consequently, the ball is attracted to the sealing wax. If the charged +sealing wax is brought near a good conductor, which is supported on +some non-conducting substance, such as glass, silk, or rubber, over +which electricity will not flow, a much more complete separation of the +two kinds of electricity occurs on the conductor than on the pith ball. +If the charged sealing wax is brought near one end of a metal rod so +placed, the charge of negative electricity upon the sealing wax will +attract the positive electricity on the metal, to that end, and will +repel the negative electricity to the other end. When a pith ball, hung +by the silk thread, is brought close to either end of the metal rod, +when the charged sealing wax is near the other end, the pith ball will +be attracted toward the rod; but will not be attracted if placed close +to the middle of the rod. This proves that the metal rod is electrified +only in the parts nearest to and farthest away from the charged body. +The two kinds of electricity neutralize each other at the parts in +between. + +If now we take two conductors and place them end to end, we have +for all practical purposes, a single conductor. It has the decided +advantage, however, of being easily separated into two parts. When an +electrified substance is brought close to one end of such a conductor, +a charge of one kind is attracted to the near portion of the conductor, +and a charge of the opposite kind is repelled to the farther part. By +separating the two parts of the conductor, we learn that one of the +ends, which have been in contact, is charged with positive and the +other with negative electricity. + +This act of separating the two kinds of electricity upon a conductor by +means of a charge upon another body which is not permitted to come into +contact with the conductor, is called induction, and two charges of +electricity produced in this way are known as induced charges. + +There are other ways in which a charge of electricity may be induced +upon a conductor. One end of the conductor may be connected with the +earth by means of some good conducting material, and the charged +substance brought close to the other end. A charge, opposite in +character to the initial charge, is attracted to the end of the +conductor that is near the charged body, and the electricity of the +opposite kind is repelled, through the conductor to the earth. By +securing the connection with the earth, while the charged body is +near the conductor, a charge is obtained upon the conductor, that is +opposite in character to the initial charge. This method of charging +conductors, by induction, is practically the same as the one first +described, for the earth is a conductor of electricity, and corresponds +to the more distant part of the two-piece conductor. + +An instrument, known as the electrophorus, is especially designed for +the production of electric charges by induction in the manner just +described. This instrument consists of a brass plate, on an insulating +handle of glass, and a disk of sealing wax, fitted into a brass dish, +whose edges rise somewhat higher than the surface of the wax. In using +the electrophorus the brass dish, or sole, is placed upon some support +that will conduct electricity, and the sealing wax disk is then rubbed +vigorously with a piece of flannel, or catskin, which electrifies the +sealing wax, with negative electricity. The brass plate is then taken +by the glass handle and brought close to the charged sealing wax. The +charge of negative electricity on the wax attracts a charge of positive +electricity to the under surface of the plate and repels a negative +charge to its upper surface. If the charged plate is now brought into +contact with the edge of the brass dish the negative charge, on the +back of the plate, flows away, through the legs of the dish, to the +earth, but the positive charge remains on the under surface, where +it is bound, by the attraction of the negative charge on the disk of +sealing wax. If the brass plate is now removed, it will be found to be +charged with positive electricity. + +The negative charge upon the sealing wax is not reduced or diminished +by its action in charging the brass plate, and it is possible to charge +the plate an indefinite number of times by means of one charge on the +sealing wax. + +The charges of electricity, produced in any of the ways that have been +described, are necessarily small, and the disturbance produced, when +they are destroyed by bringing oppositely charged conductors together, +is very slight, merely a little snapping noise and, perhaps, a small +spark, that seems to leap from the positively charged conductor to +the negatively charged one, when they come very close together. By +the use of electrical machines of various kinds, in some of which +the electricity is produced by friction, and in others by induction, +conductors may be charged with much larger quantities of electricity, +and the disturbance produced by their discharge is greatly increased. +The noise produced is louder and the spark much brighter, and leaps +from one conductor to the other, while they are much farther apart. +It is possible to produce still larger charges of electricity upon +conductors if they are arranged so as to form what are called +condensers. + + + + +What Is a Leyden Jar? + + +One of the commonest forms of condenser is the Leyden jar, which is so +named because it was invented at Leyden, in Holland. This is a glass +jar, upon the outside of which is fastened a coating of tinfoil, that +covers the bottom of the jar and extends two-thirds of the way up +the sides. Inside the jar there is a similar coating of tinfoil, and +through the top of the jar, which is usually made of wood, extends a +metal rod. On the upper end of the rod, there is a metal ball, and, at +the lower end, is attached a chain which runs down to the bottom of the +jar and rests upon the inner tinfoil coating. + +In using the Leyden jar, the ball on the metal rod that runs through +the top of the jar is connected with an electrical machine, and the jar +is supported upon some conducting material, through which electricity +may be conveyed from the outer coating of tinfoil to the earth. If the +inner coating of tinfoil is now charged with positive electricity, by +means of the electrical machine, it induces, upon the outer coating +of foil, a charge of negative electricity, which is bound by the +attraction of the positive charge on the inside of the jar. At the +same time, the positive electricity, on the outer coating of foil, is +repelled, through the conducting support, to the earth. + +The charge that can be communicated to the coating of the foil, inside +the Leyden jar, is greatly increased by the presence of a charge of the +opposite kind of electricity, on the coating on the outside of the jar. +Each of these charges attracts the other, through the glass of the jar, +and serves to bind or hold it. If either coating of foil is removed, +the charge on the other coating tends to fly off the tinfoil, and will +immediately do so, if a conductor is brought near. It is because the +negative effects of the initial charge, inside the jar, and of the +induced charge outside the jar, make it possible to communicate, to +each coating of foil, a larger charge than it could otherwise be made +to receive, that a Leyden jar is called a condenser. + +When a Leyden jar is disconnected from the electrical machine, two +opposite charges of electricity are present on it, one inside and the +other on the outside. If the two coats of tinfoil are now connected, by +means of a condenser, they will at once neutralize each other, and the +jar will be discharged. A jar may be discharged, by simply taking hold +of the tinfoil on the outside of the jar, with one hand, and touching +the metal rod, running through the top of the jar, with the other. +If you do this, there will be a sudden flow of electricity through +your body, your muscles will give a sudden jerk, and you will feel a +peculiar tingling sensation. In other words, you will have received a +shock. + +It is not necessary, for the hand that does not grasp the jar, actually +to touch the rod that runs through the top. If the hand is brought +toward the rod, rather slowly, you will see a spark leap across the +space between the rod and your hand, while your hand is still some +distance from the rod. The greater the distance, across which the spark +leaps, the brighter will be the spark, and the stronger the shock +produced. This distance is sometimes spoken of as the length of the +spark, and it indicates the size of the charges on the tinfoil coatings +of the jar. + + + + +Who Discovered Electricity? + + +It may seem difficult to believe, that the tiny spark and weak snapping +noise that are produced when a Leyden jar is discharged, are, in many +respects, the same as lightning and thunder, but it is nevertheless +true. This was proved by Benjamin Franklin, about the middle of the +18th century, in the following way. One afternoon, when a thunder +shower was approaching, he sent up a kite, to the string of which he +fastened a large metal key; and to the key, a ribbon of non-conducting +silk, which he held in his hand. When the rain had been falling long +enough to wet the string thoroughly, it become a good conductor of +electricity, and Franklin found that the key had become charged with +electricity transmitted from the clouds, along the wet kite string. +The non-conducting silk ribbon, that formed the continuation of the +kite string, from the key to his hand, was employed to prevent him from +receiving shocks from the passage of the electricity, through his body, +to the earth. + +Up to this point, your attention has been directed in charges of +electricity. You have been told how they may be produced, what some of +their leading properties are, and what effects they produce, when they +are discharged. The subject that will now be explained to you is that +of electric currents. + + + + +What Is an Electric Current? + + +By an electric current, is meant a flow of electricity along a +conductor. The flow of electricity, through your body, when you receive +an electric shock, is a current, but it lasts only for an instant, and +it is difficult to learn much about its nature. By the use of various +devices, it is possible to produce currents, that will continue as long +as we want them, so that we are enabled to study their properties quite +thoroughly. + +One of the oldest and simplest forms of apparatus, for producing +electric currents, is that which is known as the voltaic cell. This +form of apparatus may very easily be constructed. Pour some water into +a glass jar, and add a little sulphuric acid. Now place in the water a +strip of clean zinc and one of clean copper. Do not let the strips of +metal touch in the water, but connect them outside the water by means +of a piece of wire. When this has been done, a current of electricity +will be sent up along the wire and through the water between the two +strips of zinc and copper. This current is said to flow along the wire +from the copper, which is called the positive pole of the cell, to the +zinc, which is called the negative pole. In the liquid in the cell +(i.e., the jar), the current travels from the zinc to the copper, thus +completing what is called the electric circuit. Whenever the circuit it +broken, that is, whenever there is a gap made in the wire connecting +the poles, or anything else is done to destroy the completeness +of the path, along which the current travels, the current ceases; +consequently, when it is desirable to stop the current, all that is +necessary is to cut the wire connecting the two strips of copper and +zinc. + +The production of a current of electricity, by means of an apparatus of +this sort, depends upon the chemical action of the acid in the water +upon the strip of zinc. As long as the acid continues to act upon +the zinc, the current is produced, and when the acid ceases to act +upon the zinc, the current ceases to flow. If the zinc is clean, the +chemical action of the acid ceases, whenever the circuit is broken, and +consequently, when the cell is not being used to produce a current, +the zinc is not destroyed by the acid. But if the zinc is not clean, +small electric currents are set up, within the liquid, between the +zinc and the impurities on its surface, and around the points where +these impurities lie the acid acts upon the zinc and dissolves it. This +action of the acid upon the zinc, when the circuit is broken, is known +as local action, and it is very desirable to prevent it, as far as +possible. For this purpose the zinc is often rubbed with mercury, which +soaks into the zinc and forms a film on its surface, upon which the +impurities float. This treatment of the zinc is known as amalgamation, +and it serves to prevent almost all the local action, due to impurities +of the zinc. + +Many other substances, besides zinc and copper, have been found capable +of yielding an electric current, when placed in a suitable liquid, and +many other fluids, besides water that contains a little sulphuric acid, +have been employed to act upon the zinc and copper, or the substances +used in their stead. Numerous cells of different kinds have, therefore, +been devised, but, in all of them, the current is produced by chemical +action. Most of them contain a liquid of some sort, which is called the +exciting fluid, and two solid substances, which are called the elements +of the cell. One of these elements is always much more susceptible to +the chemical action of the exciting fluid, than the other, and this one +is known as the positive element. The other element, upon which the +exciting fluid may have no action, is called the negative element. In +cells in which the elements are zinc and copper, the zinc is always the +positive element. This may seem strange to you, for you have already +learned that the zinc is the negative pole of the cell, but, to avoid +confusion, you must fix well in your mind the fact that the zinc is +not the positive element of a voltaic cell, but its negative pole, +and that the copper, which forms the negative element is the positive +pole of the cell. The currents produced by the various forms of voltaic +cells, vary considerably in strength, but none of them are very strong. +In order to obtain a stronger current, a number of cells must be used +together. Such a collection of cells forms a voltaic battery, and in +some instances, as many as fifty thousand cells have been used in a +single battery. + +We have already learned in our study of water that it may be separated +into its elementary gases by sending an electric current through it. +The effect is a chemical one. Water, however, is not the only substance +that is decomposed by electricity; almost all chemical compounds may be +decomposed by the passage of a current through them, provided a current +of sufficient strength is used. + +Another effect of the current is its heating effect. It has been found +that the passage of an electric current, through any body, is always +productive of a certain amount of heat. The amount of heat produced +depends upon the strength of the current of electricity, and the +resistance to its passage that is offered by the body through which it +travels. This amount is increased by increasing either the strength of +the current or the resistance of the conductor along which it travels. +We have already learned, that some substances allow electricity to +pass over them very readily, and are therefore called conductors, +while substances through which electricity does not flow readily are +known as non-conductors. No substance is a perfect non-conductor, for +electricity can be made to pass through any substance, if the current +is sufficiently powerful. Neither is any substance a perfect conductor, +for all substances offer some resistance to the passage of an electric +current. Those substances that are ordinarily considered good +conductors offer varying degrees of resistance to electric currents. +For example, a copper wire offers less resistance than an iron wire of +the same length and diameter. + +The resistance of a body depends not only upon its material, but also +upon its length and size. In conductors of the same material, the +resistance is directly proportional to the length of the conductor, +and inversely proportional to the square of its diameter. This is not +surprising, for an electric current bears a strong resemblance to a +current of water, in many of its properties, and you know that it is +harder to force water through long, narrow pipes, than through short, +wide ones. + +From what has been stated about resistance, you may see, that a current +will produce more heat, in passing through a long fine wire, than +through a shorter and thicker one, and that, of two conductors of the +same length and size, but of different material, one may be heated much +more by a current than will another. + +~HOW MAGNETS ARE MADE~ + +A third effect of the electric current, which has not previously been +mentioned is its magnetizing effect. It is upon this, that some of the +most important effects of electricity depend. + +By coiling a wire around a bar of iron or steel, and then sending an +electric current through it, the piece of iron, or steel, is made to +show magnetic properties. By this is meant, as you doubtless know, that +the iron will now attract other pieces of iron, or steel, to it. The +strength of this attraction depends upon the strength of the current, +and upon the number of turns of wire around the bar. By increasing +either the strength of the current, or the number of turns in the +coil of wire, around the bar of iron, the strength of its magnetic +attraction is increased. When the current is stopped, the magnetic +properties of the iron disappear almost completely. A magnet, that +depends upon a current of electricity for its magnetic power, is called +an electro-magnet. + +Besides electro-magnets there are others, which are called permanent +magnets. Electro-magnets are composed of soft iron, the softer the +better, and, as soon as the current of electricity ceases to flow +around them, their magnetic properties disappear. Permanent magnets, +on the contrary, are made of steel, and their magnetism is independent +of the action of a current of electricity. No coil of wire is wound +around them, and no current is employed to maintain their magnetic +properties. A piece of steel may be made to become a permanent magnet, +by passing a current of electricity, for a considerable time, through +a coil of wire wound around it, or by allowing a piece of steel to +remain for some time in contact with a strong magnet. When a current of +electricity passes through a coil of wire, wound around a bar of steel, +it takes longer to magnetize the steel than it would to magnetize iron, +but, when the current ceases, the magnetism does not all disappear from +the steel. A portion of it remains, and the steel becomes permanently +magnetic. + +If a thin bar of steel is magnetized, and is then suspended by its +middle, so that it can spring freely, it will be found that one end +tends to point toward the north, and the other toward the south. +Whenever the bar is swung out of this position, it swings back to it, +and if the north end is turned entirely around to the south, it does +not remain, but swings back to its former position. This shows that +there is a difference in the magnetism at the two ends of the magnet. +To indicate this difference, the north-seeking end of a magnet is +called the positive pole of the magnet, and the south-seeking end is +known as the negative pole. + +By suspending two bar magnets, in the manner described, it can be shown +that the positive and negative poles of the magnets act like positive +and negative charges of electricity. Poles of the same kind repel, and +poles of opposite kinds attract, each other. + +Permanent magnets are usually made in two forms, either straight +or horseshoe shaped. A compass needle, as has been shown, is an +example of a straight magnet. The horseshoe variety, which has a +little bar of iron, called the keeper, laid across the poles is a +common toy. Electro-magnets are seldom seen, except in electrical +instruments or machinery. The pictures shown on the following pages +give us a bird’s-eye view of some of the wonders performed by these +electro-magnets. Tons and tons of material are picked up and held +securely by one of these magnets as easily as you can hold on to an +apple. + + + + +Why Does a Bee Have a Sting? + + +The bee’s sting is given him as a weapon of defence. Primarily it is +for the sole purpose of enabling him to help defend the hive from his +enemies. Sometimes when he is attacked away from the hive he uses his +sting to defend himself. When he does so, he injects a little quantity +of poison through the sting and that is what causes the inflammation. + + + + +How Does a Honey Bee Live? + + +The bee lives in swarms of from 10,000 to 50,000 in one house. In the +wild state the house or hive is located in a hollow tree generally. +These swarms contain three classes of bees, the perfect females or +queen bees, the males or drones, and the imperfectly developed females, +or working bees. In each hive or swarm there is only one perfect female +or queen whose sole mission is to propagate the species. The queen is +much larger than the other bees. When she dies a young working bee +three days old is selected as the new queen. Her cell is enlarged by +breaking down the partitions, her food is changed to “royal jelly +or paste” and she grows into a queen bee. The queen lays 2,000 eggs +per day. The drones do not work and after performing their duty as +males are killed by the working bees. The female bees do the work of +gathering the honey. They collect the honey from the flowers, they +build the wax cells, and feed the young bees. When a colony becomes +overstocked, a new colony is sent out to establish a new hive under the +direction of a queen bee. + + + + +THE BEGINNING OF A STEAMSHIP + + +[Illustration: Probably no form of construction is so interesting to +everyone as the construction of a huge steamer, a wonderful “city” +afloat, with its thousands of passengers, its thousand officers and +crew, the tremendous stores of provisions and water, and the precision +with which the great ship plows its way from one shore to the other. + +This picture shows the first work in building a modern steamer, laying +the keel and center plate, upon which the massive hull is constructed. +The rivets are driven by hydraulic power, noiselessly but firmly. In +the new “Britannic”--largest of all British steamers and the newest +(1915) modern leviathan--over 270 tons of rivets--nearly three million +in all--were required to give staunchness to the steel-plated hull. The +cellular double bottom is constructed between the bottom and top of the +center plate.] + +[Illustration: A LONGER VIEW OF THE ABOVE OPERATION.] + +[Illustration: THE CRADLE OF A STEAMSHIP CALLED A “GANTRY” + +VIEW NEAR THE BOW. + +The “ribs” of the “Britannic,” showing the deck divisions, in outline. +The huge “gantry” or cradle of steel, in which “Britannic” was built, +cost $1,000,000.] + +[Illustration: THE DOUBLE BOTTOM OF MODERN STEAMSHIPS + +THE “BRITANNIC” OF THE WHITE STAR LINE. VIEW OF THE DOUBLE BOTTOM +PLATED.] + +[Illustration: THE HUGE STEEL SKELETON OF THE “BRITANNIC” BEFORE THE +PLATES WERE PLACED ON IT. + +The plates are seen piled in the foreground. The largest of them are 36 +feet long and weigh 4¹⁄₄ tons each.] + +[Illustration: THE SHIP READY TO LAUNCH + +NOT A “SKYSCRAPER,” BUT A FLOATING HOTEL IN PROCESS OF CONSTRUCTION. + +THE HULL ITSELF IS 64′ 3″ DEEP, AND FROM THE KEEL TO THE TOP OF THE +FUNNELS IS 175 FEET. THE NAVIGATING BRIDGE IS 104′ 6″ ABOVE THE KEEL.] + +[Illustration: + + WHITE STAR + ROYAL MAIL STEAMER + “BRITANNIC” + +READY TO LAUNCH. + +The “Britannic” on the ways at Belfast (Harland & Wolff’s). The largest +gantries ever constructed to hold a ship.] + +[Illustration: THE MACHINERY USED IN LAUNCHING A SHIP + +FORWARD LAUNCHING GEAR (HYDRAULIC). + +The ship went from the ways into the water in 62 seconds and was +stopped in twice her own length.] + +[Illustration: THE HUGE HULL LEFT THE WAYS EASILY AND CREATED ONLY A +SMALL SPLASH.] + +[Illustration: A CLOSE VIEW OF A SHIP’S RUDDER + +“BRITANNIC” HELD UP JUST AFTER THE LAUNCH.] + +[Illustration: “BRITANNIC.” THE 100-TON RUDDER. THE (CENTER) TURBINE +PROPELLER SHAFT AND ONE OF THE “WING” PROPELLER SHAFTS.] + +[Illustration: WHAT A SHIP’S PROPELLER LOOKS LIKE + +THE COMPLETED SHIP + +The center (the turbine) propeller, 16′ 6″ in diameter, cast of one +solid piece of manganese bronze, 22 tons in weight. The “Britannic” +like “Olympic,” is propelled by two sets of reciprocating engines, the +exhaust steam from these being reused in the low-pressure turbine, +effecting great economy in coal. The two “wing” propellers are 23′ 6″ +in diameter and weigh 38 tons each.] + +[Illustration: WHAT A SHIP’S TURBINE LOOKS LIKE + +The turbine motor, 130 tons in weight (Parsons type). The steam plays +upon the blades with such power that they develop 16,000 horse-power +and revolve the propeller (turbine) 165 times a minute. The motor is 12 +feet in diameter, 13′ 8″ long, the blades (numbering thousands) ranging +from 18 to 25¹⁄₂ inches in length.] + +[Illustration: THE IMMENSE TURBINE MOTOR FULLY ENCASED--WEIGHT 420 +TONS.] + +[Illustration: HOW A FUNNEL APPEARS BEFORE IT IS IN PLACE + +One of the four immense funnels--without the outer casing. Each is 125 +feet above the hull of the ship and measures 24′ 6″ by 19′ 0″.] + +[Illustration: WHAT A GREAT STEAMSHIP WOULD LOOK LIKE IF SPLIT END TO +END] + +This view will give some idea of the interior arrangement of the +huge White Star Line triple-screw steamer “Britannic.” Many features +undreamed of a dozen years ago have been introduced in the passenger +quarters of this ship. As many decks are necessary to provide the +required space for state-rooms, public apartments, promenades, etc., +several passenger elevators have been installed, which are a great +convenience for those who find the use of stairs irksome. There is +a fully equipped Gymnasium, a children’s Play Room for the younger +passengers, a Squash Racquet Court, a Swimming Pool with sea-water, and +the Turkish Bath establishment. + +There are accommodations for over 2500 passengers as well as a crew of +950. The view shows how the ship is divided into numerous water-tight +compartments, so that should several of these sections become flooded +the rest of the ship would remain intact. + +The lifeboats, of which there are sufficient to carry all on board, are +handled by a new device, by means of which the boats can be launched, +when filled, with greater ease and safety than hitherto. Each of the +great davits can handle several boats and they are long enough to carry +the boats clear of the side of the ship, should any accident cause her +to list to one side. + +The “Britannic” is nearly 900 feet in length, and with her gross +tonnage of 50,000 is the largest British steamer in the world. + + + + +What Is Water Made Of? + + +Every kind of substance in the world is made up of tiny portions, each +of which is distinctly just what the whole mass is, but which are so +small you cannot see them. A pile of sand, or a cupful of sugar or salt +consists of a great many small grains. A cup of water too is made up of +what we would call small grains of water, or what we would call grains +of water if we could think of them in the same way as we do sugar or +salt or sand. These particles are so small that they could not be seen +separately, even if the particles did not have the ability to stick so +close together that we could not distinguish them even if they were +large enough to be seen. + +The word used in describing these tiny particles in any substance, +water, sugar, sand, salt or anything else is molecule. + + + + +What Is a Molecule? + + +The word molecule means “smallest mass,” which indicates the very +smallest division that can be made of any substance without destroying +its identity. Every substance is made up of molecules, and in many +cases the molecules of one substance will mix with those of another +substance, while in other cases they will not. When you dissolve sugar +in water or melt lead or change water into steam, the physical body of +the substance is changed, but the molecules remain as they were. They +are only changed in so far as their relations to each other and to +those of another substance are concerned. + + + + +How Do We Know a Thing Is Solid, Liquid or Gas? + + +The relations of the molecules in any substance to each other is what +determines whether a substance is a solid, a liquid or a gas. A gas is +a substance in which the molecules are constantly moving rapidly about +among each other, but always in straight lines. A liquid substance is +one in which the molecules are also constantly moving about but which +do not move in straight lines. Solids are substances in which the +molecules stick together in one position by the power of cohesion which +they have. Cohesion means the power of sticking together. + + + + +How Big Is a Molecule? + + +We do not as yet know all there is to be learned about molecules. We +know through the wonders of chemistry that small as a molecule is, it +is still made up of smaller particles called atoms. An atom is the +smallest division of anything that can be imagined. We have found by +chemistry that even a molecule is capable of being divided, i.e., it +is made up of still smaller particles, but molecules are small enough. +An eminent scientist, Sir William Thomson, has given us probably the +nearest approach to a correct way of saying something of the size of a +molecule. “If a drop of water were magnified to the size of the earth, +the molecules would each occupy spaces greater than those filled by +small shot and smaller than those occupied by cricket balls.” + +To get at what water is made of we must separate it through chemistry +into its parts or atoms. When we do this we find that a molecule of +water is made of three atoms or parts. Two of these are exactly alike +and consist of a gas called hydrogen, and the other part is another +gas called oxygen, concerning which gases we have already learned +much in the answers to other questions in this book. In other words, +when we separate water, which is a liquid, into its parts, we change +the relations of the molecules in the water which move in irregular +lines, into parts which move in straight lines and, when the molecules +of a substance, as we have already seen, move in straight lines, the +substance becomes a gas. On the other hand, when you freeze water, it +becomes a solid (ice), and in doing that you fix the molecules in the +water so that they stick to each other. + +Men thought for a long time that water was an element like oxygen and +hydrogen, i. e., that its molecules could not be separated in its +parts and was, therefore, considered one of the things which could not +be divided up, but this was due to the fact that it requires a great +amount of power to break up the molecules of water. + + + + +What Is an Element? + + +An element is any substance whose molecules cannot be broken up and +made to form other substances. You can take one or more elements and +make a compound, which is what water is. A compound is a substance in +which the molecules are made up of at least two kinds of elements or +elementary substances. + +~THE DIFFERENCE BETWEEN ELEMENTS AND COMPOUNDS~ + +The things we find in the world are known as either compounds or +elements. An element, as we have already learned, is something in +which the molecules cannot be broken up. A compound is, therefore, a +substance in which the molecules are made of molecules of one or more +elements and is either gas, liquid or solid, according to the relations +which these molecules have to each other. We have so far discovered +less than eighty real elements in the world, although since we find +a new one every little while, there are probably many more as yet +undiscovered. + +Not all elements are gases, of course. Solids like copper, gold, +iron, lead and a number of others are elements. Among liquids we have +mercury, and of the gases we find hydrogen, nitrogen and oxygen, +which are the three wonderful gases about which we are about to learn +something, and these three are also the world’s most important gases. +Ammonia is an element, but, while we think of it as a liquid, the real +ammonia is really a gas. Our household ammonia is really a compound of +ammonia with something else. + + + + +What Is Hydrogen Gas? + + +Hydrogen is one of the elementary substances in the form of a gas. It +has no color or taste or odor, so we can neither see, smell nor taste +it. It is the lightest substance known to the world. We have by the aid +of chemistry been able to catch and retain it in sufficient quantities +to weigh it and have found it to be lighter than anything else in +the world. It is soluble in water and some other liquids, but only +slightly so. It refracts light very strongly and will absorb in a very +remarkable manner with some metals when they are heated. It burns with +a beautiful blue flame and very great heat. When burned it combines +with oxygen in the air and forms water. Hydrogen is not poisonous but, +if inhaled, it prevents the blood from securing oxygen, and so the +inhaling of hydrogen will cause death. Hydrogen is not found free in +the air except in small quantities like oxygen and nitrogen and is, +therefore, secured by separating compounds by known methods. It can be +secured by the action which diluted sulphuric acid has on zinc or iron, +by passing steam through a red-hot tube filled with iron trimmings, by +passing an electric current through water and in other ways. Hydrogen +is absolutely necessary to every form of animal or vegetable structure. +It is found in all acids. + + + + +What Is Oxygen? + + +Oxygen was discovered in 1774. It is an elementary substance in +the form of a gas which is found free in the air. It is colorless, +tasteless and odorless and, like hydrogen, cannot therefore be seen, +tasted or smelled. It is soluble in water and combines very readily +with most of the elements. In most cases when oxygen combines with +other things the process of combining is so rapid that light and +heat are produced--this combination is called combustion. Where the +process of combining with other substances acts slowly the heat and +light produced at one time are not enough to be noticed. Where metals +tarnish or rust or animal or vegetable substances decay, the same +thing chemically is taking place as when you light a fire and produce +light or heat--you are making the oxygen combine with the substance +in the material which is burning. When iron is rusting or vegetables +decaying, the action is so slow that no heat or light is produced, but +the result is the same if some outside force does not stop the action. +The fire will burn until everything burnable which it can reach is +burned out, and in the case of the piece of iron rusting, the action +will go on slowly until the whole piece of iron is destroyed--or burned +out. Like hydrogen, no vegetable or animal life can live without oxygen +continually given it. Oxygen will destroy life and will sustain it. + +All of our body heat and muscular energy are produced by slow +combustion going on in all parts of the body, of oxygen carried in +the blood after it enters the lungs. In sunlight oxygen is exhaled by +growing plants. + +Oxygen is the most widely distributed and abundant element in nature. +It amounts to about one-fifth of the volume of the air belt of the +earth; about ninety per cent of all the weight of water is oxygen. The +rocks of the earth contain about fifty per cent of oxygen and it is +found in most animal and vegetable products and in acids. + + + + +What Is Nitrogen? + + +Nitrogen is the third of the world’s wonderful and important gases. +It is also without color, taste or smell. It will not burn or help +other substances to burn and it will not combine easily with any other +element. It will unite at a very high degree of heat with magnesium, +silica, and other metals. About 7.7 per cent of the weight of the air +is nitrogen, so that it is a very important part of the air we breathe +and it is absolutely necessary in making all animal and vegetable +tissues. When united with hydrogen, it produces ammonia, and with +oxygen one of the most important acids--nitric acid. It is found free +in the air and is thus easily secured. Nitrogen, while very important +to all kinds of life, is known as the quiet gas. It stays quietly by +itself unless forced to combine under great power with other things, +and, even under those conditions, will combine rarely. We find a good +deal of nitrogen in the blood but, while we need the nitrogen which is +found in the blood, it does nothing particularly to the blood or the +rest of the body. The nitrogen which the body uses is valuable to the +body only when found in a compound. This nitrogen which the body needs +is secured through vegetable products such as the wheat from which our +bread is made, and which are said to secure their nitrogen through +the aid of microbes which are able to force the nitrogen of the air +into a compound. Some day perhaps we shall know all there is to know +about nitrogen, which is the least known of these three wonderful and +necessary gases. + + + + +Why Are Some Things Transparent and Others Not? + + +Transparency is produced by the way rays of light go through substances +or not. When light strikes a substance that is almost perfectly +transparent, it means that the rays of light go through it almost +exactly as they come in. We think quickly of glass when we think of +something readily transparent. Water is almost equally as transparent. +When the sunlight is shining on one side of a pane of ordinary window +glass, it causes every thing on that side of the window to reflect the +light which strikes it in all directions. When these rays of light +strike the window pane, they go right through and that is how we are +able to see the trees and grass and everything else through a clear +window pane. The same reason applies also to the water. + +Some kinds of window glass (the frosted kind) we cannot see +through--they are not transparent. The surface of a frosted window pane +is so made that when the light rays strike it the rays are twisted and +broken, and do not come through as they entered the glass. + +Sometimes the water is almost perfectly transparent. When water is +perfectly clear, it is quite transparent. When you look at or into +water that is not transparent, you will know that there are particles +of solid matter floating about in it which twist and mix the light +rays. If the water is not too deep you can see the bottom sometimes +even when there are some particles of solid substances floating about +in it, but the deeper the water the more of these solid particles there +are generally in it, so that it is impossible in most waters to see the +bottom if the water is deep. In some places, however, the water is so +free from floating particles that the bottom of the ocean can be seen +at quite considerable depths. + + + + +Why Is the Sea Water Salt? + + +All water that comes into the oceans by way of the rivers and other +streams contains salt. The amount is so very small for a given quantity +of water that it cannot be tasted. But all this river water is poured +into the oceans eventually at some point. After it reaches the oceans, +the water is evaporated by the action of the sun. When the sun picks up +the water in the form of moisture, it does not take up any of the solid +substances which the water contained as it came in from the rivers, and +while there is about as much water in the ocean all the time and about +as much also in the air in the form of moisture also, the ocean never +gets fuller; the solid substances from the river waters keep piling +up in the ocean and float about in the water there. The salt which is +in the river water has been left behind by the sun when it evaporated +the water in the ocean for so long that the amount of salt has become +very noticeable. The moisture which the sun takes into the air from +the ocean is eventually turned back to the earth again in the form of +rain. This process of evaporation and precipitation in the form of rain +is going on all the time. When the water which is in the form of rain +strikes the earth, it is pure water. It sinks into the ground and on +the way picks up some salt, finds its way into a river sooner or later, +and then evidently gets back into the ocean. All this time it has been +carrying the tiny bit of salt which it picked up in going through the +ground. But when it reaches the ocean again and is taken up by the +sun, it leaves its salt behind and so the salt from countless drops of +water is constantly being left in the ocean as it goes up into the air. +This has been going on for countless ages and the amount of salt has +been increasing in the ocean all the time, so that the sea is becoming +saltier and saltier. + + + + +Why Does Salt Make Me Thirsty? + + +The blood in our body contains about the same proportion of salt as the +water in the ocean normally. When the supply is normal we do not feel +that we have too much salt in our systems, but when you take salt into +your mouth the percentage of salt in the body is increased, and the +being thirsty, or the desire to drink water afterwards is caused by the +demand of the human system that the salt be diluted. The system calls +for water or something to drink in order that it may counteract the too +great percentage of salt in the system. Other things also, when taken +into the body in too great a proportion, cause us to become thirsty. +Thirst is merely nature’s demand for more water on account of the +necessity of reducing the percentage of some substance like salt, or +merely a necessity for having more water in the body. + + + + +What Are Diamonds Made Of? + + +We learned the definition of an element in our study of water and +other substances. Many things which were at one time thought by our +wisest men to be elements were later found to be compounds of other +substances. Water is one of these which we have learned is really not +an element at all, but compounded from two gaseous elements, hydrogen +and oxygen. + +One of the most important elements in the world is the one out of +which diamonds are formed. Not because diamonds are so valuable, but +because the element referred to, carbon, is found in every tissue of +every living thing, both animal and mineral. This carbon is one of the +most useful of all elements, but is found in and used by living things +always in combination with some other substance. Carbon is combustible, +forming carbonic acid gas, from which the earth’s vegetation secures +its necessary carbon, which is very great in amount. + +When heat is made to act in certain ways on the tissues of animal and +vegetable life we get charcoal, lampblack and coke. Carbon will combine +with more other substances than any of the other known elements. Its +wonders lie in the fact that under various treatments it produces +altogether different looking things, although remaining as pure carbon. +Our diamonds, for instance, are pure carbon, but our lead pencils, +that is, the part we write with, are also pure carbon, and the coal +we burn is carbon also. It would be hard to say which of these three +forms of pure carbon is most valuable to the world. A great many rich +people might say diamonds, while the poor people would surely say +coal, especially if you asked them in winter, while the people who +write books, and newspaper reporters, would probably say lead-pencils. +However, it would be better to choose diamonds, for if you have them +you can always trade them for coal or lead-pencils. A very small +diamond will buy quite a lot of either coal or lead-pencils. Carbon is +one of the solid elements which are not metals. A great many of the +important elements in the group of solids are metals. + + + + +What Causes Dimples? + + +A dimple is a dent or depression in the skin on a part of the body +where the flesh is soft. The fibers which lay in the tissue under the +outside skin help to hold the skin firm. These fibers which are, of +course, small run in all directions and are of different lengths. Now +and then these fibers will just happen to grow short in one spot or the +other and pull the skin in, forming a little depression, but producing +a very pleasing effect. + + + + +Why Does the Dark Cause Fear? + + +Fear is an instinct. We are by nature afraid of the things we do not +know all about. That is why knowledge is so valuable; when we know +about a thing we are sure of our ground. When we are where it is light +we can see what is there; when it is dark our imagination becomes +active and because we do not know for certain what is there in the dark +before us, we imagine things. + +Fear of the dark, however, cannot be said to be entirely natural. It +comes naturally only when we have come to the age when we begin to +imagine things. Animals have no imaginative powers and they do not fear +the dark. Some people say that the fear of the dark is bred in us, +but little babies do not fear the dark. If they are properly trained +they will go to sleep in the dark and will prefer the dark. As they +grow older children begin to fear the dark, but that is because their +imagination is coming to life and because parents so often make the +mistake at this stage of training their children of either encouraging +the feeling of fear that darkness brings for the convenient means of +punishment it provides through threatening to put the light out, or +because they do not take the pains to show that there is no reason for +fear. + +Most children who fear the darkness are really taught to do so +permanently by parents or servants. When a boy or girl first begins to +imagine things in the dark, many parents run quickly to the child and +say, “Don’t be afraid” or “There is nothing to be afraid of,” and in +doing this they perhaps mention the word “fear” for the first time. +Repetition of this will always cause the child to associate the word +“fear” with “darkness.” As a matter of fact when the boy or girl first +shows fear of the darkness, parents should go to them and quiet their +fears, but talk about anything else but fear and direct the child’s +mind away from any thought of fear. + +[Illustration: ANCIENT EGYPTIAN ROPE.] + + + + +The Story in a Coil of Rope + + +How many have ever given a thought to the question of where rope comes +from and how it is made, or realize what a variety of uses it is put +to, and how dependent we are upon it in many of the everyday affairs +of life? But let us suppose for a moment that the world were suddenly +deprived of its supply of this very commonplace material, and of its +smaller relatives, cords and twine. We should then begin to realize +the importance of a seemingly unimportant thing, and to appreciate the +difficulty in getting along without it. + +Ancient civilized peoples had their ropes and cordage, made from +such materials as were available in their respective countries. The +Egyptians are said to have made rope from leather thongs, and our +illustration will be found interesting in this connection. This is from +a sculpture taken from a tomb in Thebes of the time of the Pharaoh of +the Exodus. + +[Illustration: EGYPTIANS MAKING ROPE.] + +While this scene is said by the best authority to represent the +preparation of leather cords for use in lacing sandals, it has been +supposed by some to be a representation of rope making. In any event +the process is undoubtedly the same as that used in making rope. + +The scene is depicted with the true Egyptian faculty for showing +details, making words almost unnecessary to an understanding of their +pictorial records. We see the raw material in the shape of the hide, +and also two well-made coils of the finished product. One of the +workmen is cutting a strand from a hide by revolving it and cutting as +it turns. Any one who has not tried it will be surprised to see what a +good, even string can be cut from a piece of leather in this way. + +Another man is arranging and paying out the thongs to a third, who is +evidently walking backward in time-honored fashion, twisting as he goes. + +Coming down to more recent times we find that rope-making had been +going on for centuries with probably very little change, up to the time +of the introduction of machinery and the establishment of the factory +system. + +[Illustration: HACKLING.] + +~HOW ROPE WAS LONG MADE BY HAND~ + +In the early days to which we have referred, all the yarn for +rope-making was spun by hand in the time-honored way. We are able to +represent to our readers by the photographs shown, this now almost lost +art. The material shown in the pictures is American hemp, which because +the earlier machines were not adapted to working this softer fiber, +continued to be spun by hand long after manila was spun chiefly on +machines. + +[Illustration: NATIVE PHILIPINO SCRAPING THE FIBER FROM THE LEAF STOCK.] + +The hemp was first hackled, as is also shown by our photograph, the +hackle or “hechel” being simply a board having long, sharp steel teeth +set into it. This combed out the tow or short, matted fiber, leaving +the clean, straight hemp. This “strike” of hemp the spinner wrapped +about his waist, bringing the ends around his back and tucking them +into his belt, thus keeping the material in place without knot or +twist, and allowing the fibers to pay out freely. + +[Illustration: DRYING THE FIBER.] + +[Illustration: SCENE IN AN EGYPTIAN KITCHEN SHOWING USE OF A LARGE ROPE +TO SUPPORT A SORT OF HANGING SHELF.] + +The workman in our picture is Johnny Moores, an old-time expert +hand-spinner, who can walk off backward from the wheel with his wad of +hemp, spinning with each hand a thread as fine and even as can be asked +for. In the photograph, in order to show the process more clearly, one +large yarn is being spun. + +[Illustration: AN OLD FASHIONED ROPE WALK + +HAND SPINNING.] + +The large wheel, usually turned by a boy, is used to convey power to +the “whirls,” or small spindles carrying hooks upon which the fiber +is fastened. These whirls, revolving, give the twist to the yarn as +the spinner deftly pays out the fiber, regulating it with skillful +fingers to preserve the uniformity and proper size of the yarn. As he +goes backward down the long walk through the “squares of sunlight on +the floor” he throws the trailing yarns over the “stakes” placed at +intervals along the walk for the purpose. + +The spinning “grounds” were usually arranged with wheels at either +end, so that spinners reaching the farther end, could go back to their +starting point spinning another set of yarns. + +Then in the case of small ropes, the strands could be made by attaching +two or more yarns to the “whirl” and twisting them together, reversing +the motion to give the strands a twist opposite to that given the +yarns. These strands were twisted together, again reversing the motion, +making a rope. Thus it will be seen that, reduced to its lowest terms, +rope-making consists simply of a series of twisting processes. The +twisting of the yarns into the strand is known as “forming” or putting +in the “foreturn.” The final process is “laying,” “closing” or putting +in the “after turn.” Horse-power was used in old times for forming and +laying rope which was too large to be made by hand. + +How all this work is now done in a modern rope factory by ingeniously +devised machinery we shall now see. + +The opening room where the fiber is made ready for the preparation +machinery is a reminder of the days when all rope-making processes +were hand work. The bales are first opened up--in the case of Manila +this means cutting the straw matting put on to protect the fiber in +shipment. Then the hanks which are packed in various ways--sometimes +doubled, sometimes twisted--are taken out and straightened and the band +at the end of the hank removed. + +No machinery has yet been perfected for doing the work just described +but the first of the preparation processes, a short step beyond, tells +quite a different story. Here the hanks of such fibers as require a +special cleaning treatment are placed on fast working hackling machines +which comb away most of the snarls, loose tow and dirt. + +At this point hard fibers--Manila, Sisal and New Zealand--are usually +oiled to soften them and to make them more workable for the operations +that follow. The oil, furthermore, acts as a preservative. It is a +matter of importance to the buyer, however, that the fiber should not +be too heavily oiled, for that merely increases the weight and cost of +the rope without improving its quality. + +The wonder of modernism in rope-making is nowhere more striking than +in the preparation room. To pass from one end, where the raw hemp is +received just as it left the hands of the native Filipino laborer with +his crude methods, down through the long rows of machines to the draw +frames from which the sliver is delivered in a form that can be likened +to a stream of molten metal, is to cover decades of inventive genius +and mechanical development. + +The mechanism performs its work so accurately that at first glance the +man feeding the fiber into the machine and all the other men, busy +about their various duties, would appear to be playing very minor parts +in modern rope making. In reality, expert workmanship and watchfulness +are very important factors. Good rope depends no more upon scientific +machine processes than upon ceaseless attention to the little details, +and this is especially true in the preparation room. + +Before taking up the distinctly modern machines so largely used now +in the final processes of rope-making--the forming of strands, laying +of common ropes and closing of cable-laid goods--we will describe the +rope-walk where much of this work is still best carried on. + +[Illustration: HUGE BALES OF RAW ROPE MATERIAL + +MANILA HEMP IN WAREHOUSE.] + +For making tarred goods in all but the smaller sizes the walk has +certain advantages not afforded by newer methods. It also provides +efficient equipment for turning out the largest ropes, which would +otherwise require special machinery. + +[Illustration: A MODERN ROPE WALK + +INTERIOR OF ROPE WALK, PLYMOUTH CORDAGE CO.] + +The long alleys or grounds where the work takes place are usually laid +out in pairs, one for forming, the other for laying and closing. Each +ground has a track to accommodate the machines used and an endless +band-rope which conveys the power. + +[Illustration: NEAR VIEW OF MACHINE IN ROPE WALK.] + +~HOW ROPE IS FORMED AND TWISTED~ + +At the head of the forming ground stand frames holding the bobbins of +yarn. The yarns for each strand first pass through a plate perforated +in concentric circles. This arrangement gives each yarn the correct +angle of delivery into a tube where the whole mass gets a certain +amount of compression. + +As the top truck is forced ahead by the twisting process, the ropemaker +by means of greater or less leverage on the “tails”--the loose ropes +shown in our picture--preserves a correct lay in the rope. The stakes +on which the strands rest are removed one by one to allow the top truck +to pass, and then replaced to support the rope until the laying is +finished and the reeling in of the rope begun. + +The closing process on cable-laid goods is like the laying except +that the twist is reversed. The work now being with three complete +ropes--frequently very large--a heavier top truck is necessary, and +this must often be ballasted, as shown in our illustration, to keep +down the vibration which would otherwise tend to lift the truck off the +track. + +[Illustration: NEAR VIEW OF MACHINE IN ROPE WALK.] + +Modern rope-making ingenuity reaches its high-water mark in the +compound laying-machine where the two operations of forming the strands +and laying them into a rope are combined. Up to a certain point this +method is more economical than that in which the forming and laying are +unconnected. Fewer machines are required for a given output--hence, +less floor space and fewer workmen. The time-saving element also enters +in. + +[Illustration: PREPARING THE FIBER IN ROPE MAKING + +OPENING BALES OF MANILA FIBER FOR PREPARATION.] + +[Illustration: PREPARATION ROOM. + +Here the fiber is carefully cleaned and combed by a series of fine +tooth machinery through which it passes.] + +[Illustration: COUNTLESS SLIVERS STREAM FROM THE ROPE MACHINE + +FORMATION OF SLIVER--FIRST BREAKER. + +The hanks of fiber are fed by hand into this machine several at a +time, where it is grasped by steel pins fitted to a slowly revolving +endless chain. A second set of pins moving more rapidly draws out the +individual fibers and combs them into a continuous form. + +The operations which follow are very similar. A number of “ropings” +are allowed to feed together into a first slowly revolving set of pins +and are drawn out again by a high speed set into a smaller sliver, the +pins becoming finer on each succeeding machine until the draw frame is +reached. Here the fiber is pulled from a single set of pins between two +rapidly moving leather belts called aprons. On all of these machines +the fiber passes between rollers as it goes onto and leaves the pins +and the sliver is given its cylindrical form by being drawn through a +circular opening. + +A finished sliver must conform to the special size desired for +spinning.] + +[Illustration: SPREADER.] + +[Illustration: SECOND BREAKER.] + +[Illustration: DRAW FRAME.] + +[Illustration: A ROPE MACHINE THAT IS ALMOST HUMAN + +FOUR-STRAND COMPOUND LAYING-MACHINE.] + +The compound laying machine must, however, be stopped each time that +the supply of yarn on any bobbin is so low as to call for a fresh one. +This would occur so frequently in the case of the larger ropes as to +offset the advantages just mentioned, hence the machine is used on a +limited range of sizes only. + +As can be seen in the picture, the machine contains a vertical +shaft with upper and lower projecting arms which support the +bobbin-flyers--four in number in this particular case. The bobbins +within each flyer turn on separate spindles, allowing the yarns to pass +up through small guide plates and thence into a tube. + +Each flyer is geared to revolve on its own axis, thus twisting its set +of yarns into a compact strand. At the same time all the flyers revolve +with the main shaft in an opposite direction and form a rope out of the +strands as the latter come together in a central tube still higher up. + +The rope is drawn through this tube by a series of pulleys which exert +a steady pull and so keep the proper twist in the rope. From these +pulleys the finished product is delivered onto a separately-driven +coiling reel, an automatic device registering meanwhile on a dial the +number of fathoms run. + +The small reel, seen near the head of the main shaft, holds the small +heart rope which is fed into the center of certain four-strand ropes to +act as a bed for the strands. + +Pure Manila rope is the very best and the most satisfactory for all +around use. The character of good Manila fiber is such as to impart to +a properly made rope such necessary factors as strength, pliability, +and wearing qualities. + +Regular 3-strand Manila rope is universally used for all general +purposes. + +For certain special uses, however, and particularly where the rope is +to be used for any kind of sheave work, a 4-strand type of construction +will be found the most suitable, as such a rope presents a much firmer, +rounder, and greater wearing surface than the ordinary 3-strand. There +are many different types of 4-strand rope. + +The picture shown on this page represents a coil of 4-strand Manila +called “Best Fall.” This rope is made of carefully selected fiber; +is 4-strand with heart, and is harder twisted than ordinary goods. +Best Fall is adapted for heavy hoisting work, as on coal and grain +elevators, cargo and quarry hoists and for pile-driver hammer lines. + +~AN AVERAGE COIL OF ROPE--1200 FEET~ + +The standard length coil of rope is 1,200 feet, although extra long +lengths are every day made for such purposes as oil-well drilling, the +transmission of power, etc., etc. + +[Illustration: SECTION, CROSS SECTION AND COIL, FOUR AND THREE-FOURTH +INCHES CIRCUMFERENCE. SECTION AND CROSS SECTION ONE-HALF ACTUAL] + +[Illustration: DIFFERENT KINDS OF KNOTS + +KNOTS. + +From Knight’s American Mechanical Dictionary. + + 1. Simple over hand knot. + 2. Slip-knot, seized. + 3. Single bow-knot. + 4. Square or reef knot. + 5. Square or bow-knot. + 6. Weaver’s knot. + 7. German or figure-of-8 knot. + 8. Two half-hitches, or artificer’s knot. + 9. Double artificer’s knot. + 10. Simple galley-knot. + 11. Capstan or prolonge knot. + 12. Bowline-knot. + 13. Rolling-hitch. + 14. Clove-hitch. + 15. Blackwall-hitch. + 16. Timber-hitch. + 17. Bowline on a bight. + 18. Running-bowline. + 19. Catspaw. + 20. Double running-knot. + 21. Double-knot. + 22. Sixfold-knot. + 23. Boat-knot. + 24. Lark’s head. + 25. Lark’s head. + 26. Simple boat-knot. + 27. Loop-knot. + 28. Double Flemish knot. + 29. Running knot, checked. + 30. Croned running-knot. + 31. Lashing-knot. + 32. Rosette. + 33. Chain-knot. + 34. Double chain-knot. + 35. Double running-knot with check-knot. + 36. Double twist-knot. + 37. Builder’s knot. + 38. Double Flemish knot. + 39. English knot. + 40. Shortening knot. + 41. Shortening knot. + 42. Sheep-shank. + 43. Dog-shank. + 44. Mooring-knot. + 45. Mooring-knot. + 46. Mooring-knot. + 47. Pig-tail, worked on the end of a rope. + 48. Shroud-knot. + 49. Sailor’s bend. + 50. A granny’s knot. + 51. A weaver’s knot.] + +[Illustration: HOW TO SPLICE A ROPE + +ENGLISH SPLICE. + +For transmission rope. + +The successive operations for splicing a 1³⁄₄-inch rope by this method +are as follows: + +1. Tie a piece of twine (9 and 10, figure 6) around the rope to be +spliced, about six feet from each end. Then unlay the strands of each +end back to the twine. + +2. Butt the ropes together, and twist each corresponding pair of +strands loosely, to keep them from being tangled, as shown (_a_) figure +6. + +3. The twine 10 is now cut, and the strand 8 unlaid, and strand 7 +carefully laid in its place for a distance of four and a half feet from +the junction. + +4. The strand 6 is next unlaid about one and a half feet, and strand 5 +laid in its place. + +5. The ends of the cores are now cut off so they just meet. + +6. Unlay strand 1 four and a half feet, laying strand 2 in its place. + +7. Unlay strand 3 one and a half feet, laying in strand 4. + +8. Cut all the strands off to a length of about twenty inches, for +convenience in manipulation. The rope now assumes the form shown in +_b_, with the meeting-points of the strands three feet apart. + +Each pair of strands is now successively subjected to the following +operations: + +9. From the point of meeting of the strands 8 and 7, unlay each one +three turns; split both the strands 8 and 7 in halves, as far back as +they are now unlaid, and “whip” the end of each half strand with a +small piece of twine. + +10. The half of the strand 7 is now laid in three turns, and the half +of 8 also laid in three turns. + +The half strands now meet and are tied in a simple knot, 11 (_c_) +making the rope at this point its original size. + +11. The rope is now opened with a marlin-spike, and the half strand of +7 worked around the half strand of 8 by passing the end of the half +strand through the rope, as shown, drawn taut, and again worked around +this half strand until it reaches the half strand 13 that was not laid +in. This half strand 13 is now split, and the half strand 7 drawn +through the opening thus made, and then tucked under the two adjacent +strands as shown in _d_. + +12. The other half of the strand 8 is now wound around the other half +strand 7 in the same way. After each pair of strands has been treated +in this manner, the ends are cut off at 12, leaving them about four +inches long. After a few days’ wear they will all draw into the body of +the rope or wear off, so that the locality of the splice can scarcely +be detected.] + + + + +Why Do We Go to Sleep? + + +First, of course, we sleep to rest our body and brain. During our +waking hours many, if not all, parts of our bodies are active all the +time, and with every movement we exhaust or spend some of our strength. +Take the case of your arm, for instance. You may be able to move it +up and down fifty or a hundred or more times without getting tired, +according to how strong you are, but sooner or later you will not be +able to move it any more--it is tired--the life has all gone out of it +and it needs rest, in order that it may become strong again. Every time +you move your arm you destroy certain parts of its tissues, which can +only be replaced during rest. Every activity of your body has the same +experience, and the constant work of the brain in directing the various +movements and activities of the body, tires it out too. As soon as this +condition occurs, the brain tells the other parts of the body that it +is time to rest, and even if we try to keep awake and go on with our +work or play, or whatever it is we are doing, we find sooner or later +that it is impossible. If we persist we fall asleep wherever we happen +to be. It is not necessary for all parts of the body to be tired before +we sleep. One part alone may be so affected by what it has been doing +that it alone causes us to fall asleep. Sometimes the eyes become so +tired, while we are looking at the pictures in a book or reading, for +instance, that we fall off to sleep quickly. It is perhaps easier to +bring on sleep by making the eyes tired than in any other way. That +is why so many people read themselves to sleep. It is such a gradual +passing into unconsciousness that you can hardly ever tell where you +left off reading. It is said that when we are awake our bodies are +continually planning for the time when we shall need sleep and are +continually making some little germ which is carried to the brain as +soon as made, and when there are a sufficient number of these little +germs piled up in the brain, we go to sleep. The process of sleeping +then destroys these germs, and when they are destroyed we again wake up. + + + + +Why Do We Wake Up in the Morning? + + +To answer this we must go back to the answer to the question, “What +makes us go to sleep?” We go to sleep in order to secure the rest which +our body and brain need to build up the parts which have been destroyed +during our active work or play. + +We wake up naturally when we have had sufficient rest. We wake up +naturally, however, only when the destroyed parts of the body have +been replaced. Other things may waken us--a noise of any kind, loud +or slight, a startling dream or a moving thing that disturbs our +sleep--according to how fully we are asleep. It is said that sometimes +only parts of the body are asleep; that we are not always all asleep +when we appear to sleep, and that we dream because some part of the +body is awake or active. This is probably true. Now then, when all of +anyone of us is sleepy, we go into what is called a deep sleep and +at such times only something out of the ordinary would awaken us. +Gradually, however, various parts of the body become rested and they +are said to wake up, and finally when all of us is rested, we naturally +wake up all over. If you are healthy and sleep naturally, in a place +where you cannot be disturbed by noises or movements of others, you +should be “wide awake” when your eyes open and be ready to get up at +once. If you feel like turning over for another snooze, when it is time +to get up, you did not go to bed as early as you should have done, +or else some part of you did not get the required amount of sleep it +should have had. + + + + +Where Are We When Asleep? + + +We are just where we lie. It seems to us, of course, because of our +dreams when we are asleep that we are away off some place else. Often +when we wake up we wonder for a minute or two where we are, as +everything seems so strange to us, and it takes a minute or so for us +to remember that we are in our own bed, if that is where we went to +sleep. This is because of the dreams we have while asleep. In past +times the uncivilized savages in various parts of the earth believed +that when any of them went to sleep that the real person so asleep +actually went away, leaving the body behind; in other words, that +the soul went traveling. They thought this because it was the only +explanation they could think of for the dreams they had, since almost +invariably the dream was about some other place. + + + + +Why Does It Seem When We Have Slept All Night That We Have Been Asleep +Only a Minute? + + +This is because all our ideas of passage of time are based on our +conscious periods. When we are asleep we are unconscious. It is the +same as if time did not pass, and when we wake up the tendency is to +start in where we left off. We have learned by experience that when +we go to sleep at night and wake up in the morning that much time has +passed and this unconscious knowledge keeps us from thinking always +that we have been asleep but a minute. But if you drop asleep in the +day time, no matter how long you sleep, you wake up thinking that +you have been asleep only a minute, and sometimes it is difficult to +convince yourself that you have been asleep at all. Sometimes after +being asleep for hours, your first waking thought is a continuation of +what your mind was on when you went to sleep. The reason for this, as +stated above, is that we cannot keep track of passing time when we are +asleep, because we are perfectly unconscious. + + + + +Why Should We Not Sleep With the Moon Shining On Us? + + +There is no harm in letting the moon shine on us while we are asleep. +This is one of the queer superstitions that has developed in the world. +A great many people think that something terrible will happen if the +moon is allowed to shine into the room where they are asleep. Not so +many believe this as used to do so, thanks to the more enlightened +condition of things in the world. + +To prove to yourself that no harm can come to you through the moon +shining into your bedroom or upon you as you are asleep, you have only +to remember that a great many men and very many more animals sleep out +under the sky every night and that the moon must shine on them while +they are asleep. As a matter of fact, people who sleep out under the +open sky are generally in possession of more rugged health than people +who sleep in beds in closed rooms. So it is rather better to let the +moon shine on you while asleep than not. + +This belief probably started with some one who had trouble in going to +sleep with the moon shining on him, because the light of the moon might +have a tendency to keep him awake. It is easier to go to sleep in a +dark room than in one that is lighted, because when there is no light +there is less about you to keep you awake. + + + + +What Makes Us Dream? + + +Dreams originate in the brain. The brain has many parts and some parts +of it may be asleep while others are not. If all parts of the brain +are actually asleep, it is said there can be no dreams. We have dreams +about things which seem very natural while we are having them, and +which we know would be impossible if we were wholly awake, because +those parts of the brain which control the other parts are probably +asleep while the dream is taking place, and it is then that we have +those fantastic and highly imaginative dreams, for the brain is not +under control in every sense. + +We used to believe that dreams have no purpose, just as now we know +that they have no meaning. But it has been discovered that dreams +have a purpose in that they protect our sleep. You see, every dream +is started by some disturbance or excitement of the body or mind. +Something may be pressing or touching us while we sleep, or a strange +sound may start a dream, or perhaps it is some uncomfortable position +in which we are lying or trouble in the stomach on account of eating +something we should not. Whatever it may be, those things wake up some +part of the brain, because if all parts of the brain were asleep, we +could not feel or hear anything. Any such disturbance or excitement +would naturally excite the whole brain and wake us up completely if it +were not for dreams. The dream takes care of this and enables the rest +of the body and brain to sleep while one or more parts of the brain are +disturbed and even perhaps awake. We may perhaps have become uncovered +in some way. This would produce a cold feeling and might wake a part +of the brain and cause a dream about skating or some other winter +amusement or experience, or even perhaps one about falling through the +ice, and still we might not be uncovered so much that it would make any +great difference. The dream comes and we go on with our sleep without +waking up, whereas if it were not for the dream we would awaken. In +other words, dreams are just another wise provision of nature which +enables us to go right on and get the rest we need, even if our +digestion is out of order, or some part of our brain is disturbed +through something we read about, or were told of, or we thought of +while still awake. + + + + +Why Do We Know We Have Dreamed When We Wake Up? + + +Because we remember some of our dreams. Sometimes we do not remember +the dreams we dreamed. This is just like what happens when we are +awake. We remember some things and forget others. + +Dreams are a sort of safety valve in our sleep. We dream because not +all of our brain is asleep at the time and it is a wise provision of +nature that permits the waking part of the brain to go on working +without disturbing the sleep of the other parts of the brain. If a +large part of the brain is awake and engaged in making the dream, +we are very apt to remember the dream; but when we dream and cannot +remember what the dream was, it is because only a very small portion of +the brain was awake and making a dream. + + + + +What Causes Nightmare? + + +A nightmare is a dream of what we might call a vigorous kind. A +nightmare is caused by a feeling of intense fear, horror, anxiety +or the inability to escape from some great danger. A nightmare is +the result of either an irregular flow of blood to the brain or by a +stomach that is not in proper condition. + +The name for this kind of a dream comes from the words night and mare. +The latter word in one of its several meanings indicates an incubus or +evil vision, and a dream of an evil vision involving fear or horror +came to be termed a mare. Since they occurred generally at night, since +most people sleep at night, they became known as nightmares. Nightmares +are more common to children than grown-up people because children are +more apt to have an uneven flow of blood to the brain and also are more +apt to eat the things which put the stomach in a state of unrest which +causes nightmares. Grown-up people are more likely to have learned to +avoid the abuses of the stomach which are apt to produce nightmares. + + + + +What Are Ghosts? + + +The idea of ghosts is the result of a mistake of the brain or an +attempt to account for something of which we see the results, but have +no actual knowledge. There are no ghosts. There are many forces at work +in the world of which we know nothing as yet. Many of the wonderful +things that occur in the world are as yet mysteries to the mind of +man. Every little while man discovers one of these new forces, and +then he is able to understand many things plainly which were up to +then surrounded with mystery and in the minds of superstitious people +attributed to spirits or ghosts. Long before we understood as much as +we do now of the workings of electricity (and they say we know only a +little of its wonders as yet) many of the natural wonders produced by +electricity were attributed to ghosts. + +Most of the marvelous tales of the wonders performed by and visits from +ghosts are the result of disturbances of the brain in the people who +think they see the ghosts and the results of their work. + +A creature without imagination does not pretend to see or believe in +ghosts. Man is the only animal which possesses the ability to imagine +things and so the ghosts we hear about are the creatures of the +disturbed brains of men. Generally in the ghost stories we hear of, +the ghost is described as wearing clothes--usually white. A bed sheet +thrown over the foot of the bed may appear to a half-awake person as +the outline of the figure of a ghost and to one of a highly imaginative +temperament without the courage of investigation, become forever a real +ghost. Usually what is supposed to be a ghost is only a creation of +the mind--a vision such as we can develop during a dream--oftentimes, +however, what you look at when you think you see a ghost is an actual +something such as the sheet referred to, but which takes the form of +the ghost in the brain of the person who is looking at it through eyes +that really see it, but out of a brain that for the moment at least is +far off its balance. + + + + +Why Do Girls Like Dolls? + + +Girls like dolls because they come into the world for the purpose of +becoming mothers and the love which they display for dolls is the +mother instinct which begins to show itself early in life. To the +little girl the doll is a make-believe child. It satisfies her as long +as there are no real babies to take its place, but any little girl will +drop her dollie if she is given an opportunity to play at dolls with a +real live baby instead. This is a very interesting fact in connection +with the human race. Boys sometimes play with dolls, but not so often, +and any kind of a boy will give up playing with a doll as soon as a +toy engine or some other boy’s toy appears for him. A boy has certain +mannish instincts which a girl has not. We have many other instincts +besides the instinct of parenthood and each of them has its origin in +some certain kind of feeling which is born within us and is capable of +development along interesting lines. + + + + +What Makes the Works of a Watch Go? + + +A watch like any other machine which we have, only goes when power is +applied in some form or another. In the case of a watch it is a spring. +A spring is an elastic body, such as a strip of steel, as in the case +of the watch, coiled spirally which, when bent or forced out of its +natural state, has the power of recovering its shape again by virtue of +its elastic power. The natural state of a watch spring is to be open +flat and spread out to its full length. When you wind a watch you coil +this spring, i.e., you bend it out of its natural shape. As soon as you +stop winding the spring begins to uncoil itself, trying to get back to +its natural shape, and in doing so makes the wheels of the watch which +operate the hands go round. The spring then, or rather its elasticity, +which always makes an effort to get back to its natural state, is the +power which makes the watch go. Men who make watches arrange the spring +and the other machinery in the watch in such a way that it will uncoil +itself only at a certain rate of speed. Sooner or later the spring +loses its elasticity and then its power to make the watch go. + + + + +What Makes a Hot Box? + + +When you put oil on the axle, however, the oil fills up the hollows +between the little irregular bumps on both the axle and the hub, and +makes them both smooth--almost perfectly so. This reduces the friction +and keeps the axle and hub from becoming hot and expanding. The less +friction that is developed, the more easily the wheel will turn. + +[Illustration] + + + + +The Story in a Moving Picture + + +How Are Moving Pictures Made? + +To begin at the beginning, we must start with the negative stock, +or film on which the pictures are taken. This material is very much +like the films you buy for the ordinary snap-shot camera, slightly +heavier and of more durable quality, to stand the wear and tear of +passing through the picture camera and the projecting machine used in +exhibition. This film is 1³⁄₈ inches wide and comes in rolls of 200 +feet in length. This negative stock has to be carefully perforated, +making the holes necessary to conduct the film by aid of sprockets +through the camera and the projectoscope. To still further understand +this explanation, see illustrations of the negative stock. Having +prepared the film in the dark room, we can load the camera in the dark +room and proceed to take the picture. + +In taking an industrial or travelogue picture, after the camera is +in readiness, is not so much of an undertaking as taking a picture +of a drama or comedy, wherein a plot and players are concerned. The +travelogue or industrial pictures are simply photography, with the +additional manipulation of panoraming or turning the camera, which +requires an expert knowledge, acquired from experience and years of +study. There is a distinction and a big difference between the ordinary +photographer and the moving picture photographer, who is generally +known as a “camera-man.” A photographer, therefore, though of vast +experience, cannot step into a “camera-man’s” place and expect to “make +good.” The latter has to depend entirely upon his special experience +and judgment as to light and distance, focusing and general physical +conditions of the moving-picture camera, which is affected by static +and other electrical peculiarities of the atmosphere, to be avoided +by him. These, and many other points, are convincing evidence that +the moving-picture camera is entirely different from an ordinary +photographic camera. A moving-picture camera and tripod weigh from +fifty to one hundred pounds. There are two styles of cameras, one +which takes a single film and one which takes two films at once, +and each lens of the double camera must be equally well focused and +every feature to be depicted must be brought within the focus, which +generally occupies a radius of 8 feet in width by 10 feet in height. + +[Illustration: SCENES FROM “OFFICER KATE.”] + +[Illustration: RAW NEGATIVE STOCK. PERFORATED NEGATIVE STOCK. + +Exact size of a Motion Picture Film] + +When it comes to taking a photo-play, a drama or comedy, different +conditions of a varied nature have to be contended with. To proceed +intelligently in taking a photo-play, a scenario or manuscript is +essential. It must be prefaced with a well-written synopsis of the +story involved, cast of characters, scenes to be enacted and a list of +properties required in the scenes. The director, or producer, of the +play, being furnished with such a guide, proceeds to select the actors +and actresses (called players) suitable for the parts and the filling +of the cast. This being accomplished, he insists that each one of the +players read the scenario in order to be familiar with his or her +part and understand the whole play before going into the picture. The +director instructs them as to the costumes fitting the parts and then +confers with the costumer concerning the furnishing of proper dress +for each one of the players. The director is ready to go on with the +performance of the play, and tells his cast to appear for rehearsal +at a set hour. At that time he puts them through a thorough course of +training or rehearsal, to “get over” and register the meaning of each +thought which is to be expressed by their actions. Sometimes a scene is +rehearsed four to six hours before it is photographed. A one-reel play +is generally 1000 feet in length, and it is very important that the +director, if he has twenty scenes, for instance, to introduce within +that 1000 feet, to time the scenes to the length of his film; that is, +if he has twenty scenes within one thousand feet, each of the twenty +scenes must not average more than one minute each. If one should happen +to be more than one minute, then he has to condense another scene less +than one minute, in order to bring all within the twenty minutes or +1000 feet. + +[Illustration: STAGING A MOTION PICTURE IN A STUDIO + +REHEARSING SCENE IN STUDIO] + + +The Size of Each Picture on the Film. + +So you can see from this that it needs very careful rehearsal and nice +calculation to bring a well-acted and convincing play within so short +a time, to tell the whole story intelligently. Having done all this, +the director is ready to have the “camera-man” do his part of the +work. He draws his lines within the range of the camera, which do not +exceed eight or ten feet in the foreground. This is another point to be +considered on the part of the director, because all the action has to +be carried out within the eight feet of space, which is really confined +to that much stage width. Here again is where the camera-man has to +watch very carefully, not only the workings of his camera, but the +players; always alert that they are in the picture, and assisting the +director by his observations. The size of each picture as taken on the +film is ³⁄₄ by 1 inch. It is magnified ten thousand times its actual +size when we see it on the screen in a place of exhibition. A full reel +of 1000 feet shows 16,000 photographs on the screen during the twenty +minutes it consumes in its showing. The future of moving pictures is +no longer a matter of speculation. The business is an established +one, and its further developments are only matters of time. The +possibilities and uses of the animated art are unlimited. Already it +is felt in educational, religious, scientific, and industrial affairs. +Their influence in matters of sanitation and all civic improvements, +construction and mechanics, is invaluable. As a medium of wholesome +entertainment and solid instruction it is unsurpassed. + +These are merely suggestions of a few phases of its utility and it is +only a natural conclusion that it will be so far-reaching in its uplift +that it will surpass the expectations of the most sanguine. + +[Illustration: THE DEVELOPING ROOM.] + +To develop, tint and clear the films, large tanks of wood or soapstone +are used. The films, which are wound upon the wooden frames, or racks, +are dipped into these vats, filled with the necessary chemicals and +liquids. The films being wound on frames enables the developers to +examine them without handling them. The tinting is done by similar +methods to give the necessary tint, coloring in red, sepia, blue, green +or yellow, imparting to them the effect of night, sunlight or evening, +whichever the case may be. The films are finally cleared, to wash them +clear of any extraneous chemicals or matter which might streak or +scratch the films, and avoid any objectionable matter that might mar +their appearance when shown on the screen or in the process of handling. + +~EACH PICTURE IS FIRST EXHIBITED AT THE STUDIO~ + +As soon as convenient after a film is finished it is taken to the +exhibition rooms, at the studio, where it is thrown onto the screen. It +is reviewed first by the heads of the departments and the directors, +and later by players and all those interested in it. The projectoscopes +or moving-picture machines are run by motor, presided over by licensed +operators, who are kept on the job continually. + +These exhibition rooms are called, in the parlance of the studios, +“knocklodeums,” for here is where everything is criticised. Players’ +acting and fitness are judged by their appearance and conduct on the +screen and decision given as to their qualifications. The quality of +the photography, developing and the picture as a finished production is +here determined by the heads of the concern. + +[Illustration: DRYING ROOM.] + +~THE BOARD OF CENSORS PASSES ON EVERY PICTURE~ + +Every picture before it is released for exhibition must be passed upon +by the Board of Censors. It is run upon the screen and thoroughly +inspected, criticised, and every point involved thoroughly weighed +as to its effect upon the mind of the general public. If, in their +estimation, it is found objectionable in any particular, the +objectionable parts are eliminated, and if considered entirely harmful, +in its sentiments or influence, the picture is condemned. The majority +rules in the board’s judgment, although it is by no means infallible in +its decision. This board is composed of about sixty persons, who are +appointed by the government for their general qualifications, their +interest in the general welfare of the public, keenness as to morals +and uplift of the people at large. They do not receive salaries; their +services are _pro bono publico_. + +[Illustration: TAKING A MILITARY SCENE OUTDOORS.] + + + + +THE STORY IN “PIGS IS PIGS” + + +[Illustration: “PIGS IS PIGS.”] + +[Illustration: + + VITAGRAPH FAMOUS AUTHORS’ SERIES BY ELLIS PARKER BUTLER. + + _You Have Seen Pigs, but Never Such Pigs as These. Two of Them Become + Eight Hundred Pigs so Rapidly, They Set Bunny Daffy and Almost Ruin + the Express Business._ + + _Director_--GEORGE D. BAKER. _Author_--ELLIS PARKER BUTLER. + + CAST. + + _Flannery, an Express Agent_ JOHN BUNNY + _Mr. Morehouse_ ETIENNE GIRARDOT + _Clerk in Complaint Dept._ COURTLAND VAN DEUSEN + _Head of Claims Dept._ WILLIAM SHEA + _Mr. Morgan, Head of Tariff Dept._ ALBERT ROCCARDI + _President of Company_ ANDERS RANDOLF + _Prof. Gordon_ GEORGE STEVENS + +After a strenuous argument with Flannery, the local Express Agent, +Mr. Morehouse refuses to pay the 30c charges on each of two guinea +pigs shipped him, claiming they are pets and subject to the 25c rate. +Flannery replies, “Pigs is pigs and I’m blame sure them animals is +pigs, not pets, and the rule says, ‘30c each.’” Mr. Morehouse writes +many times to the Express Company, claiming guinea-pigs are not common +pigs, and each time is referred to a different department. Flannery +receives a note from the Tariff Department inquiring as to condition +of consignment, to which he replies, “There are eight now! All good +eaters. Paid out two dollars for cabbage so far.” The matter finally +reaches the President, who writes a friend, a Zoological Professor. +Unfortunately that gentleman is in South Africa, causing a delay of +many months, during which time the pigs increase to 160. At last word +is received from the learned man proving that guinea-pigs are not +common pigs. Flannery is then ordered to collect 25c each for two +guinea-pigs and deliver the entire lot to consignee. There are now 800 +and Flannery is horrified to find Morehouse has moved to parts unknown. +He is about to give up in despair when the company orders him to +forward the entire collection to the Main Office, to be disposed of as +unclaimed property, in accordance with the general rule.] + +[Illustration: BUNNY FEEDING THE PIGS.] + +[Illustration] + + +Who Made the First Moving Pictures? + +~THE FIRST MOVING PICTURE CAMERA~ + +The first device which produced the motion-picture effect was nothing +but a scientific toy. The idea is almost as old as pictures themselves. +This toy we speak of was called a zoetrope. It consisted of a whirling +cylinder having many slits in the outside through which you could see +by looking into the cylinder a picture opposite each slit. The pictures +were drawn by hand and the artist aimed to place the pictures within +the cylinder in such order that each succeeding one would represent the +next successive motion of any moving object in making a movement as +near as he could draw it; when the cylinder was whirled with the slits +on a level with the eye, the effect produced was of a continuous moving +picture. + +A great many devices were produced as a result of this toy for +presenting the effect of pictures so arranged, but until photography +was invented no way was found for making the pictures to be viewed +except such as were drawn by artists. But when photography was +developed it was possible to get actual successive photographs. +The greatest difficulty was found in taking photographs in such +quick succession that all of the motions in the moving object were +taken without any skipping. This difficulty was for the first time +successfully overcome by Muybridge in 1877. He arranged a row of +twenty-four cameras with string trigger shutters, the string of each +shutter being stretched across a race track. A moving horse approaching +down the track broke the strings as he came to them, thus operating +each of the cameras in turn in quick succession and securing a series +of pictures of the moving horse within a very short time. There were +twenty-four pictures to this film when reproduced in the devices then +known for projecting pictures, and this method required one camera for +each section of the picture produced. Of course, the length of the +series was thus limited greatly. + +About ten years later Le Prince arranged what he called a multiple +camera. This was as a matter of fact a battery of sixteen automatically +reloading cameras in which strips of film were used. Each of the +sixteen cameras took a picture in turn and then automatically brought +another strip of the film into position, so that camera number one took +the seventeenth picture, the twenty-third, the forty-ninth, etc., and +each of the other cameras took their various pictures in turn. With +this camera a film of any required length could be produced. + +The Le Prince camera was therefore the real parent from which +the modern motion-picture camera sprang. The first really modern +motion-picture camera was built in a single case with a battery of +sixteen separate lenses and sixteen shutters. These were operated by +turning a crank. The pictures were taken on four strips of film. When +the crank was turned the exposure was made to each of the sixteen +lenses in succession, and when the series was completed the films +were cut apart and pasted together in a single strip of film, the +pictures themselves being arranged in the proper order. The principal +development of this camera, as found in the present method of making +motion pictures, is the invention of the flexible film negatives; the +transparent support for the print which permits the pictures to be +projected in enlarged form upon a screen; and the system of holes in +the margin of the film by which the film is held in perfect alignment +for projecting the pictures. + +But a few years ago, then, the motion picture was a child’s toy. To-day +it forms the basis for not only a very large and profitable business +for many people, but a source of amusement and education to millions +of people at reasonable prices. To-day the motion-picture business is +regarded as one of the world’s greatest industries. + +No corner of the world is so far remote but the motion-picture man +finds his way there, either as an exhibitor or as a producer. Nothing +happens in the world to-day but the motion-picture man with his +camera is on the job if it is a happening that can be preserved in +motion pictures and worthy of that. The dethronement of kings and the +inaugurations of presidents are all alike to him. If there is a war, he +is found in all parts of the field, and is the first to see the parade +when there is a peace jubilee. Disasters, horrors, heroes and criminals +pass before his lens and he gives us a moving panorama of everything +that is interesting, in nature, in real life, and in fiction. + + +Taking Motion Pictures a Simple Operation. + +Motion-picture photography is mechanically simple and the projection of +the pictures on the screen was made possible by the improvement in dry +plates which made instantaneous photography successful, together with +the invention of the process of using celluloid films for negatives. +Motion pictures consist of a series of photographs made rapidly and +then projected rapidly on the screen. In this way one picture follows +another so quickly that the change from one picture to another is +not noticed and the movements and actions of the persons or things +photographed are reproduced in a life-like manner. + + +Is the Hand Quicker Than the Eye? + +There is no question that the hand can be moved so quickly that the +eye cannot detect the movement. This is proved by the motion picture +when projected on the screen. In moving pictures the quickness of +the machine deceives the eye and the transition from one picture to +another is done so rapidly that the change is not seen and the apparent +movement is continuous and unbroken. + +The film made by the motion picture is a “negative” in which the colors +are reversed, the blacks being white and the whites black, exactly as +in still photography. The film used in the projection machine is a +“positive,” in which the lights and shadows have their proper values. +The principle and process is exactly the same as in making lantern +slides and window transparencies. + + +Does the Film Move Continuously? + +In making the negative for the motion picture the film does not move +forward regularly, but it goes by jumps. It is absolutely still at the +moment of exposure. The same is true in projecting the picture on the +screen. In most projection machines the film is stationary three times +as long as it is in motion, though in some machines the proportion is +one in six. In the taking of the picture, the film is really stationary +one-half of the time. As pictures are usually projected at the rate +of fourteen or sixteen to the second, this means that each separate +picture appears on the screen three-fourths of one-sixteenth of a +second, or three-sixty-fourths of a second, and + + +How Are Freak Pictures Made? + +Freak pictures are usually the result of clever manipulation of the +camera or the film. Articles or individuals can be made to instantly +disappear by stopping the camera while the article is removed or the +person walks off the stage, the other characters holding their pose +until the camera is again put in motion. In some films in which a +person is thrown from a height or is apparently crushed under a steam +roller the effect is gained by the live person walking away after the +camera is stopped and a dummy substituted to undergo the death penalty. + +By projecting the picture at a faster rate than it was taken, +excruciatingly comic scenes are sometimes devised. An automobile going +ten miles an hour, by speeding up the projection machine, may be made +to apparently move at a hundred miles an hour, and by increasing in +the same way the apparent speed of persons dodging the demoniac auto +exceedingly ludicrous effects are had. + +By mechanical means in combining two or more negatives into one +positive a man can be shown fencing with himself or even cutting his +own head off. + + Pictures by courtesy of the Vitagraph Company. + +[Illustration: HOW RUBBER TIRES ARE MADE + +WASH ROOM.[4]] + + [4] These and the following Pictures by courtesy of the Goodyear Tire + and Rubber Co. + + + + +The Story in a Ball of Rubber + + +How Crude Rubber Is Treated. + +_Washing._--When the crude rubber arrives at the factory of the rubber +manufacturer, it is generally stored in bins in dark and fairly cool +store-rooms, where it is kept until ready to be used. The rubber passes +directly from the storage bins to the wash-room, where it is cut up +into small pieces, put into large vats of warmed water and allowed +to soak, in order to soften it sufficiently to be broken down in the +machines. It is then fed into a cracker, a machine consisting of two +rolls with projections on their surfaces shaped like little pyramids, +the two rolls revolving with a differential, one going considerably +faster than the other, and being adjustable, so that they can work +close together or with some distance between them. The rubber is fed +between these rolls and broken down into a coarse, spongy mass. Water +flows on to the rubber during the process, bringing down sand, dirt, +bark, and the many other foreign materials which come mixed with the +rubber. The rubber is put through this machine a number of times, until +it is worked into a uniform condition. Some of the rubbers, like the +Ceylons and Paras, will sheet out into a coarse sheet by being put +through this machine; others, like the majority of the African rubbers, +will fall apart and come down in chunks and have to be fed into the +machine with a shovel. + +[Illustration: PREPARING CRUDE RUBBER FOR MAKING TIRES + +CALENDER ROOM.] + +After the rubber is broken down sufficiently in the cracker, it is +next put through a washing machine, which is built very similar to +the cracking machine, except that the rolls are grooved or rifled, so +that their action is not so severe on the rubber. A large quantity of +water is kept constantly running over this machine while the rubber +is being put through, and the rolls work very close together, so that +the rubber is finely ground and run out into a thin and comparatively +smooth sheet, allowing the water flowing between the rolls to take out +practically all of the foreign matter that remains. The rubber is run +through this machine a number of times until the experienced inspectors +in charge are satisfied that it is thoroughly washed. Some types of +rubber, such as Manicoba, which have large quantities of sand in them, +are washed in a special form of washing machine known as the beater +washer. This is an endless, oval-shaped trough with a fast-revolving +paddle-wheel. In this machine the rubber is submerged in water, after +being broken down in the cracker, and the sand is literally knocked out +of it by the paddle-wheel. The sand drops to the bottom of the machine, +where if is drained off, while the rubber floats to the top and is +there gathered and then put through a regular washing machine for the +final sheeting out. + +_Drying._--From the wash-room the rubber goes to the dry-room. Before +the rubber can be used in any articles of commercial value, it must +be thoroughly dried, as any moisture in the stock would turn to steam +during the vulcanizing process and cause blisters or blow-holes to form +in the goods. There are two ways in which rubber is usually dried. +The method mostly used, and which is generally practiced with all the +better grades of gums, is to hang the washed strips on horizontal +poles and space them in aisles, so that air can freely circulate all +around the surface of the rubber, the dry-room being kept at a constant +temperature. To properly dry the rubbers by this method takes from four +to six weeks. The other method of drying is by means of a vacuum-drier. +Low-grade rubbers which have a comparatively large percentage of +resin in their composition cannot bear their own weight when hung on +horizontal poles, but drop off and stick in piles on the floor. Hence, +these rubbers have to be dried in a peculiar manner. They are laid in +trays which are placed into a large air-tight receptacle. The air is +then withdrawn from this receptacle and the interior heated by means of +steam coils. This allows the water to be evaporated off from the rubber +at a considerably lower temperature than that at which water boils +under atmospheric pressure, and at such a low temperature, and in such +a short time, that the rubber is not affected. By this process these +rubbers can be dried in a few hours. + +_Mixing._--After the rubber has been thoroughly dried, it is ready to +be mixed in proper proportions with the various ingredients which are +used in rubber compounding, to give the desired quality of rubbers for +the various products for which they are intended. In order that rubber +shall vulcanize, it is necessary to mix with it a certain proportion +of sulphur, vulcanizing, or curing, as it is sometimes called, being +merely the changing of a physical mixture of rubber and sulphur into +a chemical compound of these ingredients, by the application of heat. +Besides sulphur, some of the more important ingredients used in +compounding rubber are: + +_Zinc oxide._--This toughens the rubber and increases its wearing +properties and tensile strength. + +_Barium sulphate._--This stiffens the rubber and adds weight, so +reducing the cost. + +_Lithopones._--This whitens the stock and makes it soft, and is used +extensively in druggists’ sundries. + +_Antimony sulphide._--This makes the stock red and is a preservative +against oxidation. + +_Litharge._--This has the same action as antimony sulphide, but makes +the stock black. + +_White lead._--This hastens the cure and is extensively used in gray +and black stocks, and is a good filler or weight adder. + +_Magnesia oxide and carbonate._--These are used as fillers for white +stocks. + +_Oxide of iron._--Used for coloring red and yellow stocks. + +_Lime_ (unslacked).--This hastens vulcanization and chemically removes +any water left in the rubber. + +_Whiting._--This is used only as a cheap filler to increase quantity +and lower cost. + +_Aluminum silicate._--This is used chiefly as a filler. + +There are also used in compounding what are known as the various +substitutes. These are chiefly linseed oil products and mineral +hydrocarbons which are more or less elastic, and act somewhat as a flux. + + +Why Don’t We Use Pure Rubber? + +There seems to be a general impression that the various ingredients +which are mixed with rubber are put into the compounds merely to +cheapen the product and to lower the grade of the material. This +is true in many cases, such as the general line of molded goods, +rubber heels, bicycle grips, automobile bumpers, etc., but in many +cases, such as tires, packing, belting, etc., these ingredients are +added to toughen the gum, increase its wearing qualities, to make it +indestructible when subjected to heat, or to make it soft and yielding +so that it can be forced into fabric, etc. + +~PROCESS NECESSARY TO MAKING RUBBER GOODS~ + +In the general process of manufacture the sheeted rubber is sent +directly from the dry-room to the compound-room, where the various +ingredients are weighed out into proper proportions along with the +rubber to make up a batch, and placed in receptacles ready to be mixed. +The batch is then sent into the mill-room to be mixed into a uniform +pasty mass, which is the characteristic uncured, or so-called green, +rubber compound. The mixing is done in the mill. This is a very heavy +machine, constructed similarly to a cracker and a washer except that +it is much larger and heavier, and the rolls are perfectly smooth and +run closer together. No water at all is used on the batch during the +mixing. There are steam and cold water connections to the mills which +are connected with hollow spaces inside the rolls, so that the latter +can be kept at any temperature desired. The general process of mixing +is as follows: + +First the rubber portion of the batch is thrown into the mill and +is worked and warmed up until it takes on a very sticky and plastic +consistency. When it has arrived at a certain stage of plasticity, +the various compounds in the batch, which are always in the form of +very fine powders, are thrown in the mill, being worked by the rolls +into the rubber. The compounds are generally thrown on, a small amount +at a time, until they are all taken up by the rubber. The batch is +then allowed to go through and through the mill, over and over again, +until the mixture is absolutely uniform throughout the whole mass. The +consistency of the rubber, during this operation, is such that the +batch can be made endless around one of the rolls of the mill, so that +it is constantly feeding itself between the rolls. + +After the batch is properly mixed, it is cut off the rolls in sheets +and rolled up and sent to the green-stock store-room. In this +store-room the compounded, uncured gums are kept in different bins, +according to the nature of the compound, and are there allowed to +season a certain length of time, after which they are delivered to the +various departments of the factory in which they are going to be used. + +Another form in which rubber is used is the so-called Rubber-Cement. +Rubber or any of its compounds are readily soluble in naphtha. In this +process, the compounds, after being milled, are chewed up and washed +in specially constructed cement-mills and there mixed with a certain +proportion of naphtha which gives a thick solution. + +_Spreading and calendering._--Rubber which is used for the general +line of molded goods, solid tires, some kinds of tubing, etc., goes +directly to the various departments from the green-stock store-room, +while rubber used for boots and shoes, waterproof fabrics, many of +the druggists’ sundries, belting, pneumatic tires, inner tubes, etc., +has to be sheeted out, and some of it forced into fabric before it +goes to the various departments. This sheeting-out of the gum, as well +as applying the rubber to fabrics, is done generally by two methods; +either by spreading a solution of the rubber and naphtha onto the +fabric, or by calendering the rubber between heavy rolls in a rubber +calender. + +In the spreading process, a machine called a spreader is used. The +fabric to which the rubber is to be applied is mounted in a roll at +one end of the spreader and from the roll passes through a trough of +rubber-cement, and then up over a so-called doctor roll, and under a +knife edge, which allows only enough cement to pass through to fill the +pores of the fabric. From this knife the cemented fabric passes over +a steam drying chest and is then rolled up with a roll of liner cloth +to prevent its sticking together. Fabric treated in this manner must +be put through the spreader a number of times before it has sufficient +rubber on it to be used in the products for which it is intended. + +For calendering rubber, a machine called a rubber calender is used. +This machine is made with three and sometimes four heavy rolls, which +are capable of very fine adjustment. The rubber from the green-stock +store-room is first warmed up on a small mixing mill and is then fed +between the rolls of the calender, coming through in a thin sheet of +required thickness, and is wound up in a liner cloth and sent directly +to the departments, where it is used for inner tubes, druggists’ +sundries, etc., where only rubber and no fabric is used. Where the +rubber is to be applied to fabric, the fabric is put through the +calender rolls with the rubber, and the rubber is literally ground into +the fabric. Fabric treated in this manner is known to the trade as +friction, and is generally used in the manufacture of pneumatic tires, +belting, hose, etc. For boots, shoes, and other special work, calenders +are used which are equipped with rolls engraved with the shapes of the +soles and other parts of the articles in question, so that the sheet +of rubber coming from the machine has imprinted on it the shapes and +thickness of the articles for which it is intended. + +After passing through such of the above processes as are required +the rubber is ready to be made up into the various articles known to +the rubber trade, such as boots and shoes, mackintoshes, waterproof +fabrics, for balloons, aeroplanes, tentings, etc., mechanical goods, +such as rubber heels, horseshoe pads, packing, tiling, automobile and +other bumpers, artificial fish bait, etc., druggists’ sundries, such as +nursing-bottles, nipples, syringes, bulbs, hot-water bottles, tubing, +etc. tobacco pouches, rubber belting, golf and other balls, insulated +wire, fire and garden hose, inner tubes, tires, and the many other +commodities into the manufacture of which rubber enters. + +[Illustration: TRADING ROOM] + + +How Are Automobile Tires Made? + +From the calender room of the rubber factory the stock is received +in the automobile tire department, in the form of large rolls of +rubber-coated fabric, and in rolls of sheeted rubber of various +thicknesses and widths. The rubber-coated fabric is first cut into +strips of proper widths so that the edges will extend from bead to +bead over the crown of the tire. These strips are always cut on the +bias, generally at a 45-degree angle, with the edge of the roll, and +were formerly all cut on a cutting-table, a table about 50 feet long +and 6 feet wide, covered with sheet metal. The cutting was done by two +men, each having a knife and each cutting half-way across the cloth +along the edge of a straight-edge so arranged as to be always set at 45 +degrees with the edge of the table. This method of cutting is gradually +being put aside by the use of the bias cutter, an extremely up-to-date +machine having jaws which ride up to the end of the fabric and pull +it for a certain distance under a knife set at a 45-degree angle, the +knife being set to cut just when the jaws have arrived at the limit of +their motion. The action is repeated so that the machine cuts about +eighty strips a minute. These strips are fed onto a series of belts +which carry them to where they are placed, by boys, into a book having +a leaf of common cloth between each strip of gum fabric, to prevent the +strips from sticking together. + +[Illustration: CURING ROOM--SOLID TIRES.] + +[Illustration: MAKING A PNEUMATIC TIRE + +CURING ROOM, FIRST CURE--PNEUMATICS.] + +[Illustration: SPREADER ROOM.] + +The majority of automobile tires to-day are machine built, but there +are still a great many built by hand and this is the process we shall +describe first. In this process the books of fabric are laid up and +spliced into proper lengths to go around the tire and allow a proper +lapping for the splices. The proper number of these laid-up pieces, +or plies, as they are called, are placed together with cotton cloth +between and taken to the tire builder. The tire builder mounts the +core, upon which the tire is to be built, on the building stand, +generally cementing it so that the first ply of fabric will stick in +place. The first ply is then stretched onto the core and spliced, +rolled down with a hand roller onto the sides of the core, and trimmed +with a knife at the base. The following plies are put on and rolled +down in the same manner, the beads being put in at the proper time, +according to the size and the number of plies to be used. After all the +plies have been put onto the core the so-called cover rubber is put on. +This cover rubber is generally a sheet of rubber about one-sixteenth of +an inch thick or more, and of the same compound as the rubber on the +fabric. + +[Illustration: HOW THE TREAD OF A TIRE IS MADE + +TREAD LAYING ROOM.] + +In the case of the machine-built tire, the result is the same, but the +stock is handled as follows: After the rubber-coated fabric has been +cut on the bias cutter, the strips are spliced and rolled up in rolls +on a spindle which is placed in the so-called tire-building machine. +The tire core is mounted on a stand attached to the machine, so that it +can be revolved by power, and the fabric is drawn onto the core from +the spindle under a certain definite tension. The tire-machines roll +the fabric down by power, and the beads are put into place before the +tire and core are removed from the machine. Thereafter the process is +the same as in the case of the hand-built tires. + +After the cover rubber is in place the tire is ready to have the tread +applied. The tread is made up independently of the tire by laying up +narrow strips of rubber, in different widths, in such a way that the +center of the tread is thicker than the edges. In the case of the +so-called single-cure tires, which are wholly vulcanized at one time, +this tread is applied to the tire directly after the cover, a strip of +fabric called the breaker-strip generally being placed underneath, and +the building of the tire so completed. + +In the general method of curing, the tire is allowed to remain on +the core, and is either bolted up in a mold and put into an ordinary +heater, or it is laid in a mold and put into a heater press, where the +hydraulic pressure keeps the two halves of the mold forced together +during the vulcanizing process. After the vulcanizing is completed, the +tire is removed from the mold, the inside is painted with a French +talc mixture, the tire inspected and cleaned, and so made ready for the +market. In some methods of curing, instead of the tire being put in a +mold, it is put into a so-called toe-mold, which is virtually a pair of +side flanges only reaching up as high as the edges of the tread on the +side of the tire. After the flanges are fastened into place, the whole +is cross-wrapped, the cross-wrapping coming in direct contact with +the tread. The tire in this condition is then put into the heater and +vulcanized, giving the so-called wrapped tread tire. Still another form +of curing is to inflate a kind of canvas inner tube inside the tire and +place the whole in a mold. This is known as the air-bag mold process. + +[Illustration: PNEUMATIC-TIRE ROOM--SHOWING TIRE-BUILDING MACHINES.] + + +How Are Inner Tubes Made? + +Inner tubes for pneumatic tires may be classed under three headings, +according to the methods used in their manufacture, viz., seamed tubes, +rolled tubes, and tube-machine tubes. By far the greater number of +tubes come under the first two headings. For seamed tubes, the rubber +is taken from the calender in the form of sheets from one-sixteenth to +three-sixteenths of an inch in thickness. These sheets are cut into +strips of proper length and just wide enough to make a tube of proper +cross-section diameter when the two long edges are folded over and +fastened together with rubber cement. These two long edges are cut on a +bevel so that they make a good lap seam. The tube is then pulled over a +mandrel of proper size and a thin piece of wet cloth rolled around it, +and then it is spirally cross-wrapped with a long, narrow piece of wet +duck for its entire length. The whole is then put into a regular heater +and the tube vulcanized. After vulcanizing the wrapping is removed and +the tube stripped from the mandrel, turning the tube inside out, so +that the smooth side which is vulcanized next to the mandrel appears +outside, and the rough side showing the marks of the cross-wrapping is +inside. The valve hole is then punched in the tube, the valve inserted +and the open ends of the tube buffed down to a feather edge. The tube +in this state passes to the splicers, who cement the buffed ends and +splice them together, placing one open end within the other, making a +lapped seam around the tube about 2¹⁄₂ inches long. The cement used +in splicing is generally cured by an acid which chemically vulcanizes +the rubber without the application of heat. The tube is thus finished +and ready for the market. Rolled tubes are made from very thin sheet +rubber by rolling same over a mandrel of proper size, until the +required number of layers of thin rubber have been rolled on to give +the tube the desired thickness. The tube is then wrapped, cured and +spliced, in exactly the same manner as a seamed tube. + + +What Is Rubber? + +Crude rubber is a vegetable product gathered from certain species of +trees, shrubs, vines and roots. Its characteristic peculiarities were +early recognized by the natives of the tropical countries in which it +is found. Records of the earliest travelers in these countries show +that the natives had used various articles, such as receptacles, ties, +clubs, etc., made from rubber, but it was not until about 1735 that +rubber was first introduced into Europe. In civilization rubber was +first used for pencil erasers and in waterproof cloth, and finally in +cements. Vulcanizing, or the curing of rubber, was not discovered until +1844, and thereafter the development of the rubber industry was very +rapid, especially in Great Britain. + +[Illustration: WRAPPING ROOM--PNEUMATICS.] + +There are many kinds and grades of rubber, and to-day these can be +divided into two chief classes, wild and cultivated. + +[Illustration: PNEUMATIC-TIRE ROOM, SHOWING TIRE FINISHING.] + +[Illustration: HOW THE CRUDE RUBBER IS SECURED + +Gathering Rubber in South America.] + +[Illustration: 1. Tapping Axe. 2. Tin Cup to Catch the Rubber Milk. 3. +The Beginning of a Rubber “Biscuit.” 4. A Palm Nut.] + +[Illustration: Making Balls of Crude Rubber.] + +[Illustration: Tapping the Trees in Japan.] + +[Illustration: How the Rubber Looks when it comes to Market.] + +[Illustration: Carrying Balls of Crude Rubber to Native Market.] + +Pictures herewith by courtesy of The B. F. Goodrich Company, Ltd. + + +What Is Wild Rubber? + +~WHERE RUBBER COMES FROM~ + +The first class, or wild rubbers, are collected from trees which have +grown wild and where no cultivation processes whatsoever have been +used. These rubber-producing trees, shrubs, etc., are found mostly in +Northern South America, Central America, Mexico, Central Africa and +Borneo. + +The finest rubber in the world is Fine Para, and is gathered in the +Amazon regions of South America. This rubber has been gathered in +practically the same way for over a century. The natives go out into +the forests and, selecting a rubber tree, cut “V”-shaped grooves in the +bark with a special knife made for the purpose, these grooves being +cut in herring-bone fashion diagonally around the tree, with one main +groove cut vertically down the center like the main vein in a leaf. +The latex, or milk-like liquid, of the tree, from which the rubber is +taken, flows from these veins and down the center vein into a little +cup which the natives place to receive it. After the little cups are +filled they are gathered and brought into the rubber camp, and there +the latex is coagulated by means of smoke. This is done by the use of +a paddle which is alternately dipped into a bowl of the latex and then +revolved in the smoke from a wood or palm-nut fire. This smoke seems to +have a preservative effect on the rubber as well as drying it out and +causing it to harden on the paddle, each successive layer of the latex +causing the size of the rubber ball or biscuit to increase. When a +biscuit of sufficient size has been thus coagulated it is removed from +the paddle and is ready for shipment to countries where rubber products +are manufactured. + +Para rubber is sold in three grades. Fine Para, which is the more +carefully coagulated or smoked rubber; Medium Para, which is rubber +gathered and smoked in the same way as Fine, but which has had +insufficient smoking, and, therefore, more subject to deterioration due +to oxidation, etc.; and Coarse Para, which is rubber gathered from the +drippings from the rubber trees after the cups have been removed. This +latter grade has generally a large percentage of bark and other foreign +substances mixed with it, and is subject to even more deterioration +than is Medium Para, as it is oftentimes not smoked at all. + +Another important grade of rubber coming from South America is Caucho. +This tree grows similar to the Para trees and the rubber is gathered +in a similar manner, but is cured by adding to the latex some alkaline +solution and allowing the whole to dry out in the sun. The value of +this rubber can be greatly improved by better methods of coagulation. + +From Central America and Mexico comes the Castilloa rubber. This +rubber is gathered from trees in a very similar manner to Para, and is +coagulated by being mixed with juices which are obtained by grinding +up a certain plant which grows in the Castilloa districts. After being +mixed with this plant juice, the Castilloa is spread out in sheets on +bull hides, where it is allowed to dry in the sun, after which the +rubber is rolled up and is ready for shipment. Castilloa is gathered +mostly from wild trees, but in Mexico it has recently been cultivated +to some extent. + +From Mexico we also get Guayule. This rubber is obtained from a certain +species of shrub, the shrub being cut down and fed into a grinding or +pebble mill where the branches are crushed and ground and mixed with +water, and the rubber, which is contained in little particles all +through the wood, is worked out, being taken from the pebble mills in +chunks as large as a man’s fist. + +From Central Africa and from Borneo come the so-called African gums, +such as Congo, Soudan, Massai, Lapori, Manicoba, Pontianic, etc. Some +of these rubbers are gathered from trees, but most of them from vines +and roots, and the methods of coagulation are varied. Practically all +of them are dried out in the sun. These rubbers are all of lower grade +than the Para rubbers of South America. + +[Illustration: BAGS OF CACAO BEANS.] + + + + +The Story in a Stick of Chocolate + + +Where Does Chocolate Come From? + +Perhaps no other one thing is so well known to boys and girls the world +over as chocolate. Yet there was a time, and not so many years ago, as +we figure time in history, when there were no cakes of chocolate, or +chocolate candies to be had in the candy shops, no chocolate flavored +soda water or chocolate cake. To-day quite a panic would be started if +the world’s supply of chocolate were cut off. + +Chocolate is obtained from cacao, which is the seed of the cacao tree. +It is quite often called cocoa, although this is not quite a correct +way of spelling the word. The cacao tree grows to a height of sixteen +or eighteen feet when cultivated, but to a greater height when found +growing wild. The cacao pod grows out from the trunk of the tree as +shown in the picture, and is, when ripe, from seven to ten inches +long and from three to five inches in diameter, giving it the form +of an ellipse. When you cut one of these pods open, you find five +compartments or cells, in each of which is a row of from five to ten +seeds, which are imbedded in a soft pulp, which is pinkish in color. +Each pod then contains from twenty-five to fifty seeds, which are what +we call “cocoa beans.” + +The cacao tree was discovered for us by Christopher Columbus, so that +we have good reason to remember him aside from his great discovery of +America. The discovery of either of these would be fame enough for any +one man, and it would be difficult for some boys and girls to say just +which of the two was Columbus’ greater discovery. + +Columbus found the cacao tree flourishing both in a wild and in a +cultivated state upon one of his voyages to Mexico. The Indians of +Peru and Mexico were very fond of it in its native state. They did not +know the joy of eating a chocolate cream, but they had discovered the +qualities of the cacao bean as a food and had learned to cultivate it +long before Columbus came to Mexico. + +Columbus took some of the cacao beans back with him to Spain and to +this day cacao is much more extensively used by the Spaniards than by +any other nation. The first record of its introduction into England is +found in an announcement in the _Public Advertiser_ of June 16, 1657, +to the effect that: + +“In Bishopgate Street, in Queen’s Head Alley, at a Frenchman’s house, +is an excellent West Indian drink called chocolate, to be sold where +you may have it ready at any time and also unmade, at reasonable rates.” + +Of course, by the time America became settled the people brought their +taste for chocolates with them. + +[Illustration: VIEW OF COCOA BEANS IN BAG AND COCOA-GRINDING MILL.] + + +What is the Difference Between Cacao and Chocolate? + +When the cacao seeds are roasted and separated from the husks which +surround them, they are called cocoa-nibs. Cocoa consists of these nibs +alone, whether they are ground or unground, dried and powdered, or of +the crude paste dried in flakes. + +Chocolate is made from the cocoa-nibs. These nibs are ground into an +oily paste and mixed with sugar and vanilla, cinnamon, cloves, or other +flavoring substances. Chocolate is only a product made from cocoa-nibs, +but it is the most important product. + +[Illustration: CACAO CRACKING MILL AND SHELL SEPARATOR.] + +[Illustration: COCOA CRACKING AND SHELL SEPARATOR. + + WHERE THE SHELLS ARE SEPARATED FROM THE BEAN.] + +[Illustration: COCOA MILL.] + + +What Are Cocoa Shells? + +There are other products which are obtained from the cacao seed. One is +called Broma--which is the dry powder of the seeds, after the oil has +been taken out. + +Cocoa shells are the husks which surround the cocoa bean. These are +ground up into a fine powder and sold for making a kind of cocoa for +drinking, although the flavor is to a great extent missing and it is, +of course, not nearly so nourishing as a drink of real cocoa. + +[Illustration: COCOA ROASTER. + + MILL IN WHICH THE BEANS ARE ROASTED.] + + +What is Cocoa Butter? + +The oil from the cacao seeds, when separated from the seeds, is what we +call cocoa butter. It has a pleasant odor and chocolate-like taste. It +is used in making soap, ointments, etc. + +[Illustration: HOW CACAO BEANS GROW + +COCOA TREE WITH FRUIT KNOWN AS COCOA PODS, WHICH CONTAIN THE COCOA +BEANS.] + + +How is Cacao Gathered? + +When the cacao pods ripen on the tropical plantations, where the +climate is such that they can be grown successfully, the native laborer +cuts off the ripened pods as we see him doing in the picture showing +the pods on the tree. He does this with a scissors-like arrangement of +knives on a long pole. + +As he cuts off the pods he lays them on the ground and leaves them to +dry for twenty-four hours. The next day they are cut open, the seeds +taken out and carried to the place where they are cured or sweated. + +In the process of curing or sweating, the acid which is found with the +seeds is poured off. The beans are then placed in a sweating box. This +part of the process is for the purpose of making the beans ferment and +is the most important part of preparing the beans for market, as the +quality and the flavor of the beans and, therefore, their value in the +market, depends largely upon the ability of whoever does it in curing +or fermenting. + +Sometimes the curing is done by placing the seeds in trenches or holes +in the ground and covering them with earth or clay. This is called +the clay-curing process. The time required in curing the cacao beans +varies, but on the average requires two days. When cured they are +dried by exposure to the sun and packed ready for shipping. At this +time beans of fine quality are found to have a warm reddish color. The +quality or grades of beans are determined by the color at this stage. + +[Illustration: CHOCOLATE MILL.] + + +How Chocolate is Made. + +When the cacao beans arrive at the chocolate factory they are put +through various processes to develop their aroma, palatability and +digestibility. + +~PROCESSES IN CHOCOLATE MAKING~ + +The seeds are first roasted. In roasting the substance which develops +the aroma is formed. The roasting is accomplished in revolving +cylinders, much like the revolving peanut roasters, only much larger. +After roasting the seeds are transferred to crushing and winnowing +machines. The crushing machines break the husks or “shells,” and the +winnowing machine by the action of a fan separates the shells from the +actual kernel or bean. The beans are now called cocoa-nibs. These nibs +are now in turn winnowed, but in smaller quantities at a time, during +which process the imperfect pieces are removed with other foreign +substances. Cacao beans in this form constitute the purest and simplest +form of cacao in which it is sold. The objection to their use in this +form is that it is necessary to boil them for a much longer time, in +order to disintegrate them, than when they are ground up in the form of +meal. For that reason the nibs are generally ground before marketing as +cacao or cocoa. + +Another form in which the pure seeds are prepared is the flaked +cocoa. This is accomplished by grinding up the nibs into a paste. +This grinding is done in a revolving cylinder machine in which a drum +revolves. In this process the heat developed by the friction in the +machine is sufficient to liquefy the oil in the beans and form the +paste. The oil then solidifies again in the paste when it becomes cool. + +[Illustration: CHOCOLATE FINISHER.] + +What we know as cakes of chocolate are made from the cocoa-nibs by +heating the mixture of the cacao, sugar and such flavoring extracts as +vanilla, until an even paste is secured. This paste is passed several +times between heavy rollers to get a thorough mixture and finally +poured into molds and allowed to cool. When cool it can be taken from +the molds in firm cakes and wrapped for the market. This is the way +Milk Chocolate is made. The difference in the taste and consistency of +milk chocolate depends upon how many different things the chocolate +maker adds to the pure cocoa-nibs to produce this mixture. Often +substances such as starchy materials are added to make the cakes more +firm. They add nothing to the quality of the chocolate. + +[Illustration: CHOCOLATE MIXER.] + +~HOW CHOCOLATE CANDIES ARE MADE~ + +Chocolate-covered bonbons, chocolate drops, and the many different +kinds of toothsome confections are prepared in the American candy +factories, as we all well know. The chocolate covering of this +confectionery is generally put on by dipping the inside of the choice +morsel in a pan of liquid chocolate paste and then placing the bits in +tins to allow them to cool and harden. + +[Illustration: CHOCOLATE MIXING AND HEATING MACHINE.] + +A great many of the choicest bits of confectionery are now produced by +machines entirely. These machines are almost human, apparently, as we +see them make a perfect chocolate bonbon which is delivered to a candy +box all wrapped for packing. These wonderful machines thus give us +candy which has not been touched by the hands of any one prior to the +time we thrust our own fingers in the brightly-decorated box and take +our pick of the assortment it offers. + +[Illustration: WHERE THE INDIVIDUAL PIECES OF CONFECTION ARE WRAPPED.] + +[Illustration: THE TALLEST BUILDING IN THE WORLD + +WOOLWORTH BUILDING, NEW YORK CITY. + +This building, the tallest in the world, is equipped with 26 gearless +traction elevators. + +Two of the elevators run from the first to the fifty-first floor with +actual travels of 679 feet 9¹⁄₂ inches and 679 feet 10¹⁄₄ inches, +respectively. There is also a shuttle elevator which runs from the +fifty-first to the fifty-fourth floor. + +Total height of building from curb to base of flagstaff, 792 feet.] + +[Illustration: HOW AN ELEVATOR GOES UP AND DOWN + +COMPLETE GEARLESS TRACTION ELEVATOR INSTALLATION.] + + + + +How Does an Elevator Go Up and Down? + + +Ordinarily, when we think of an elevator we think merely of the cage or +car in which we ride up or down. But the car is really only the part +which makes the elevator of service to man, and from the standpoint of +the machinery, is a relatively unimportant part of the equipment. + +There are two principal types of elevators used to-day; the hydraulic, +which is worked by water under pressure, and the electric, which is +worked by electricity through an electric motor. The latter type, +because of the tendency towards the general use of electricity in +recent years, has largely superseded the hydraulic, and, as when you +think of elevators you probably have in mind those you have seen in +some huge skyscraper, we shall look at one of these. + + +What are the Principal Parts of an Elevator? + +The most advanced type of elevator to-day is called a Gearless Traction +Elevator. In this elevator the principal parts are a motor, a grooved +wheel on the motor shaft called a driving sheave and a brake, all +mounted on one cast-iron bed-plate; a number of cables of equal length +which pass over the driving sheave and thence around another grooved +wheel called an idler sheave, located just below the driving sheave, +and to one end of which is attached the car or cage, and to the other +end a weight called a counterweight; also a controller which governs +the flow of electric current into the motor and thereby the speed, +starts and stops of the elevator car. Although the controller, motor, +brake and sheaves are usually placed way at the top of the building out +of our sight, they are really very important parts of the elevator. + +The cage or car in which we ride is held in place by tracks built +upright in the elevator shaft, and the counterweight at one side of the +shaft travels up and down along two separate upright tracks. When the +car goes up the counterweight on the other end of the cables goes down +an equal distance. The counterweight is used to balance the load of the +car and to make it easier for the motor to move the car. + +Electricity is the power that makes the car go up or down. The operator +in the car moves a master switch--in one direction if he wishes to go +up, in the other direction if he wishes to go down. This master switch +sets the electro-magnetic switches of the controller at the top of the +hatchway into action, electrically, and the controller in turn allows +the electric current to flow into the motor. The motor then begins +to revolve, gradually at first, and then faster, turning the driving +sheave with which it is directly connected. As this driving sheave +revolves, the cables passing over it are set in motion, and the car and +counterweight to which they are attached begin to move. + + +Why Does Not the Car Fall? + +[Illustration: THE PRINCIPAL PARTS OF AN ELEVATOR] + +Of course, the question of safety is a very important one in any +elevator, and you wonder what would happen if the cables broke. You +think of this especially when you are going up in one of the big +skyscrapers--where the elevators sometimes travel to a height of 700 +feet. It can be truthfully said that on every modern elevator there +are safety devices which should make it practically impossible to have +a serious accident, due to the fall of the car. Every elevator is +equipped with wedging or clamping devices which automatically grip the +rails in case the car goes too fast either up or down. These gripping +devices can be adjusted to work at any speed that is desired above the +regular speed. It is not at all probable that all the cables will break +at once, because there are usually six of these, and any one of them is +strong enough to hold the car if the others break; but even if they all +should break the gripping devices on the rails will operate and hold +the car safely, just as soon as it starts down at great speed. + +Suppose that the car should descend at full speed, but not sufficiently +fast to work the rail-gripping devices, it would be brought to a +gradual rest at the bottom of the hatchway, because of the oil-cushion +buffer against which it would strike. This is a remarkable invention, +with a plunger working in oil in such a way that a car striking it +at full speed will come to rest so gradually that there is scarcely +any shock. You have perhaps seen a clever juggler on the stage throw +an ordinary hen’s egg high into the air and catch it in a china dish +without cracking it He does it by putting the dish under the falling +egg just at the right moment, and bringing the dish down with the egg +at just the right speed, so that eventually he has the egg in the dish +without cracking it. The trick is in calculating the rate of speed of +the falling egg accurately and adjusting the insertion of the dish +under the falling egg to a nicety. The oil-cushion buffer in the modern +elevator works in very much the same way. + +[Illustration: GENERAL ARRANGEMENT OF ROPING FOR GEARLESS TRACTION +ELEVATOR INSTALLATION.] + +If it were not for the genius which has made possible these new types +of elevators we could not have the high buildings. The elevators in the +Woolworth Building are the latest type in modern elevator construction. +In this one building alone there are 29 elevators, and when you are +told that the electric elevators in the United States installed by +a single company represent a total of 525,000 horse-power, you will +have some idea of the power required to operate elevators all over the +country. + + + + +Does Air Weigh Anything? + + +Air is very light, so light that it seems to have no weight at all; +but, if you will think a minute you will see that it must have some +weight, because birds fly in it and balloons can be made to float +through it. It has been found that one hundred cubic inches of air +at the sea level weighs, under ordinary conditions, about thirty-one +grains. This seems a very small weight, but when we remember the +thickness of the atmospheric envelope over the earth we see that it +must press quite heavily upon the earth’s surface. There is a very +simple instrument called a barometer, which is used for measuring the +amount of this pressure. The name means pressure-measure. + +Another striking feature of air is its elasticity, and this explains +something that is noticed by all mountain climbers. On a high mountain, +it is difficult to get enough air to the lungs, though one breathes +rapidly and deeply. The reason is, that the air at the foot of the +mountain is compressed by the weight of that above it, and consequently +the lungs can hold more of it than of the air on the mountain top, +which has less weight resting upon it and is, therefore, not so much +compressed. On account of the ease with which it is compressed, we find +that more than half of all the envelope of air that surrounds the earth +is within three miles of the surface. + +When air is chemically analyzed it is found to consist of a number of +substances mingled together, but not chemically united. These include +nitrogen, oxygen, argon, carbonic acid gas, water vapor, ozone, nitric +acid, ammonia, and dust. + +Oxygen is the most important of these constituents, for it is the part +that is necessary to support life. Yet, notwithstanding its importance, +it forms only about one-fifth of the entire bulk of the atmosphere. + +Oxygen is a very interesting substance and many striking experiments +may be performed with it. If a lighted candle is thrust into a vessel +filled with oxygen, it burns very much more rapidly and brilliantly +than in air. A piece of wood with a mere spark on it bursts into flame +and burns brightly when thrust into oxygen, and some things that will +not burn at all in air, can be made to burn very rapidly in oxygen. For +example, if a piece of clock spring be dipped in melted sulphur and +then put into a jar of oxygen, after the sulphur has been set on fire, +the steel spring will take fire and burn fiercely. The heat produced is +so great that drops of molten steel form at the end of the spring, and +falling on the bottom of the jar, melt the surface of the glass where +they strike. + +The other two substances found in pure air, nitrogen and argon, are +very much alike. They make up the remaining four-fifths of the air, and +are very different from oxygen in nearly every respect. + +Nitrogen and argon resemble oxygen in being colorless, odorless, and +tasteless gases; and they are of nearly the same weight as oxygen, +argon being a little heavier and nitrogen a little lighter; but here +the similarity ends. Oxygen is what we call a very active substance. +As we have seen, it causes things to burn very much more rapidly in it +than in air. Nitrogen and argon, on the contrary, put out fire. If a +lighted candle is put into a jar of nitrogen or argon its flame will be +extinguished as quickly as if put into water. + +We must now consider the impurities found in air. Of these the most +important is carbonic acid gas, or, as it is frequently called, carbon +dioxide. It is always produced when wood or coal is burned, and +is, of course, constantly being poured out of chimneys. It is also +produced in our lungs and we give off some of it when we breathe. It +is colorless, like the gases found in pure air, has no odor or taste, +and is considerably heavier than oxygen or nitrogen. In its other +properties it is much more like nitrogen than oxygen, for when a +candle is put into it the flame is extinguished at once. To find out +whether air contains carbonic acid gas, it is only necessary to force +it through a little lime water, in a glass vessel, and watch what +change takes place in the water. Fresh lime water is as clear as pure +water; but after forcing air containing carbonic acid through it, it +becomes turbid and milky. If the turbid water is allowed to stand for +a time, a white powder will settle to the bottom, and if we examine +this powder, we find it to be very much the same thing as chalk. While +it is true that air generally contains only a very small portion of +carbonic acid gas, there are some places in which it is present in such +large quantities as to render the air unfit for breathing. The air at +the bottom of deep mines and old wells often has an unusually large +proportion of this gas, which, because of its great weight, accumulates +at the bottom, and remains confined there. The presence of a dangerous +quantity of the gas in such places may be detected by lowering a candle +into it. + + + + +Why Does the Scenery Appear to Move When We Are Riding in a Train? + + +When you sit in a moving train looking out of the window it appears +as though the fields, the telegraph poles and everything else outside +were moving, instead of you. This is because our only ideas of motion +are arrived at by comparison, and the fact that neither you nor the +seats of the car or any other part of the inside of the car is changing +its position, leads you to the delusion that the things outside the +car are moving and not you. If you were to pull down all the curtains +and the train were making no noise at all, you would not think that +anything was moving. It would appear as though you were motionless just +as everything in the car appears so. When you turn then to the window, +and lift the curtain you carry in the back of your mind the idea of +being at rest and that is what makes it appear as though the fields and +everything outside were moving in an opposite direction. + +This is particularly noticeable when you are in a train in a station +with another train on the next track. There is a sense of motion if one +of the trains only is moving and you feel that it is the other train, +because you are surrounded by objects in the car which are at rest, +and when you look out at the other train with this half consciousness +of rest in your mind, it appears as though the other train were moving +when as a matter of fact it is your train. If the delusion happens to +be turned the other way, it will appear as though you are moving and +the other is still. It depends upon what cause the impression starts +with. + + + + +Why Don’t the Scenery Appear to Move When I am in a Street Car? + + +If you are in a street car in the country and moving along fast you +will receive the same impression, especially in a closed car, because +you are looking out of one hole or one window. In an open car you +do not receive the same impression because your range of vision is +broader. You can and do, although perhaps unconsciously, look out on +both sides and the impression your mind gets through the eyes is not +the same. If you were to pull down all the storm curtains in a moving +open street car, and then look out of one little crack, you would think +the outside was moving. But if you stop to remember that you are moving +and not the things outside the car, then the impression vanishes. In +the city, of course, your brain is so thoroughly impressed with the +fact that houses and pavements do not move, and the cars move so much +more slowly, that it is difficult to make yourself believe otherwise. +The impression is more difficult always when you are moving through +or past objects with which you are perfectly familiar. It is all, of +course, a question of impressions. + + + + +Why Does the Moon Travel With Us When We Walk or Ride? + + +The moon does not really travel with us. It only seems to do so. The +moon is so far away that when we walk a block or two or a hundred, we +cannot notice any relative difference in the relative positions of the +moon and ourselves. When a thing is close at hand we can notice every +change in our position toward it, but when it is far away the change of +our position toward it is so slight that it is hardly perceptible. A +very good way to illustrate this is to ask you to recall the last time +you were in a railroad train looking out at the scenery in the country. +The telegraph poles rush past you so fast you cannot count them. The +cows in the pasture beside the railroad do not seem to go by so fast. +You can count them easily. The tree farther over in the next field does +not appear to be moving but slightly, while the church steeple which +you can see far in the distance, does not go out of sight for a long +time--in fact, seems almost to be moving along with you. The moon is +just like the church steeple in this case, except that it is so much +farther away that it seems to travel right with you. It is all due to +the fact as stated at the beginning of this answer, that the relative +positions of yourself and the moon are only slightly changed as you +move from place to place, so slight in fact as to appear imperceptible. + + + + +Is There a Man in the Moon? + + +The markings which we see on the face of the moon when it is full can +by a stretch of the imagination be said to form the face of a man. On +some nights this face appears to be quite distinct. If, however, we +look at the moon through a telescope, we see distinctly that it is +not the face of a man. Through a very large telescope we can see very +plainly that the marks are mountains and craters of extinct volcanoes. +It just happens that these marks on the moon, aided by the reflections +of the light from the sun, which gives the moon all the light it has, +make a combination that looks like a face. + + + + +Does the Air Surrounding the Earth Move With It? + + +This is one of the old puzzling questions which many a high-school +student has had to struggle with to the great amusement of the teacher +who asks for the information and such other scholars who have already +had the experience of trying to solve it. + +To get at the right answer you have merely to ask one other question. +If the air does not revolve with the earth, why can’t I go up in +a balloon at New York, and stay up long enough for the earth to +revolve on its axis beneath me, and come down again when the city of +San Francisco appears under the balloon, which should be in about +four hours? If that were possible, travel would be both rapid and +comfortable, for then we could sit quietly in a balloon while the earth +traveling beneath us would get all the bumps. + +No, the atmosphere surrounding the earth moves right along with the +earth on its axis. If it were not so, the earth would probably burn +up--at least no living thing could remain on it--since the friction of +the surface of the air against the surface of the earth would develop +such a heat that nothing could live in it. + + + + +Why Does Oiling the Axle Make the Wheel Turn More Easily? + + +If you look at what appears to be a perfectly smooth axle on a bicycle +or motor car through a powerful magnifying glass, you will find that +the surface of the axle is not smooth at all, as you may have thought, +but covered with what appear to be quite large bumps or irregularities +in the surface. If you were to examine the inside of the hub of the +wheel in the same way, you would find that it also is like that. Now, +when you attempt to turn a wheel on the axle without oil, these little +irregularities or bumps grind against each other, producing what we +call friction. As friction develops heat, the metal of the axle and the +hub expand and the wheel gets stuck. + + + + +What Made the Mountains? + + +There is no question but that at one time the surface of the earth was +smooth, i. e., there were no big hills and no deep valleys. That was +before the mountains were made. The earth was a hot molten mass that +began to cool off from the outside inward. It is still a hot molten +mass inside today. The outside crust became cooler and cooler and the +crust became deeper and deeper all the time. Then when there would be +an eruption of the red-hot mass inside, the earth’s crust would be +bulged out in some places and sucked in in others and would stay that +way. The bulged out place became a range of mountains and the sucked +in place became a valley. This process went on happening over and over +again until the crust of the earth became firmly set. Volcanos caused +some of these eruptions, as also did earthquakes. There are today +gradual changes occurring which to a certain extent change the outside +surface of the earth, and it is possible that new mountain ranges will +be produced in this way. + + + + +What Makes the Sea Roar? + + +The roar of the sea is a movement of the sea which causes the same kind +of air waves or sound waves that you make when you shout, excepting +that, of course, the vibrations do not occur so quickly in the sea and, +therefore, the sound produced is a low sound. It is no different in +any sense than the same noise would be if the same air waves could be +produced on the land away from the water. + + + + +Why Is Fire Hot? + + +When a fire is lighted it throws off what we call heat rays or waves. +These waves are very much like the waves of light which come from a +light or fire or the air waves which produce sounds. The rays of light +and heat which come from the sun are like the rays of light and heat +from a fire. Heat is of two kinds--heat proper which is resident in the +body, and radiant heat which is the kind which comes to us from the +sun or from a fire. This radiant heat is not heat at all, but a form +of wave motion thrown out by the vibrations in the ether. The heat we +feel is the sensation produced upon our skins when it comes in contact +with the waves created by the fire. Heat was formerly thought to be an +actual substance, but we know now that radiant heat is known to be the +energy of heat transferred to the ether which fills all of space and is +in all bodies also. The hot body which sets the particles of either in +vibration and this vibrating motion in the form of waves travels in all +directions. When these vibrations strike against our skin they produce +a heat sensation; striking other objects these vibrations may produce +instead of a heat sensation, either chemical action or luminosity. This +is determined by the length of the vibratory rays in each case. + + + + +When I Throw a Ball Into the Air While Walking, Why Does It Follow Me? + + +When you throw a ball into the air while moving your body forward or +backward, either slowly or fast, the ball partakes of two motions--the +one upward and the forward or backward motion of your body. The ball +possessed the motion of your body before it left your hand to go up +into the air because your body was moving before you threw it up, and +the ball was a part of you at the time. + +If you are moving forward up to the time you throw the ball into the +air and stop as soon as you let go of the ball, it will fall at some +distance from you. Also if you throw the ball up from a standing +position and move forward as soon as the ball leaves your hand the ball +will fall behind you, provided you actually threw it straight up. + +Of course, you know that the earth is moving many miles per hour on +its axis and that when you throw a ball straight into the air from a +standing position, the earth and yourself as well as the ball move +with the earth a long distance before the ball comes down again. The +relative position is, however, the same. We get our sense of motion by +a comparison with other objects. If you are in a train that is moving +swiftly and another train goes by in the opposite direction moving just +as fast, you seem to be going twice as fast as you really are. If the +train on the other track, however, is going at the same rate of speed +and in the same direction as you are, you will appear to be standing +still. + +Going back to the ball again, you will find that it always partakes of +the motion of the body holding it in addition to the motion given when +it is thrown up. + + + + +What Good Are the Lines On the Palms of Our Hands? + + +It cannot be said that the lines on the palms of our hands are of any +great service to us. Indeed it is doubtful if they are of any value +in themselves, outside of the possible aid they may be in helping us +to determine the character of the surface of things which we grasp or +touch. It is possible that they aid in some slight degree in this way. +There is little doubt, however, that they are a result of the work the +hands are constantly called upon to do rather than contrived for any +particular service. The habitual tendency of the fingers in grasping +and holding things throws the skin of the palms into creases which +through frequent repetition make the lines of the palms permanent in +several instances. + +The peculiarities of these lines or creases in various individuals +as to details and length and variations is the chief basis of the +so-called science of palmistry. + + + + +What Makes Things Whirl Round When I Am Dizzy? + + +The medical term that describes this condition of turning or whirling +is vertigo, which means in simple language “to turn.” There are two +kinds of dizziness--one where the objects about us seem to be turning +round and round and the other where the person who is dizzy seems to +himself to be turning round and round. + +One cause of this is due to the fact that when you are dizzy the +eyes are not in complete control of the brain and the eyes moving +independently of each other look in different directions and produce +this turning effect on the brain, since each eye then sends a different +impression to the brain instantly. + +The principal cause of the sense of dizziness is, however, the little +organ which gives us our power to balance and which is located near the +ears. Sometimes this organ becomes diseased and people affected in this +way are almost continually dizzy. Whenever this organ of balance is +disturbed we lose our idea of balance and the turning sensation occurs. + +It is easy to make yourself dizzy. All you do is to turn round a few +times in the same direction and stop. In doing this you disturb the +little organ of balance and things begin to turn apparently before your +eyes. If you turn the other way you right matters again or if you just +stand still matters will right themselves. There is no great harm in +making yourself dizzy and very little fun. + + + + +Why Are the Complexions of Some People Light and Others Dark? + + +This difference in the complexions of people is due to the varying +amounts of pigment or coloring material in the cells of which the skins +of all animals is made up. Very light people have very little pigment; +very dark people, those with dark eyes and black hair, have a great +deal of this coloring material in their cells. A great many people are +neither light or very dark. They have less than the dark-complexioned +people and more than the light-complexioned people. When the hair +turns gray it is because the pigment has disappeared. As this is due +to the loss of this coloring material, dark-complexioned people turn +gray sooner than light-complexioned people. The structure of the skin +showing how these cells are made in layers can be seen by examining the +skin with a microscope. + + + + +What Makes Me Tired? + + +Men were wrong for a long time in their conclusions as to what produced +the tired feeling in us. + +We know now that every activity of our body registers itself on the +brain. When we move an arm or leg a great many times we soon feel +tired. Every time you move your arm the movement is registered in the +brain, and after a number of these movements are registered the tired +feeling in the arm appears. It is said that every movement of any part +of the body really produces certain defective cells and that these +accumulate in the blood. When these reach a certain number the tired +feeling takes possession of us, and when we rest, the blood under +the guidance of the brain, goes to work and rebuilds these defective +cells. We know that a change takes place in the blood when we become +tired because, if you take some of the blood from an animal that shows +unmistakable signs of fatigue and inject it into an animal that shows +no tired feeling at all, the second animal will begin to show signs of +fatigue even though it is not active at all. + +We used to think that being tired indicated that our bodies were in +need of food and that the way to overcome it was to eat a big meal. +We did not stop to think that even when we are hungry the human body +has sufficient food supply stored up to keep it going for days without +taking in new food. Of course, this mistake was made because we knew +that our power and energy came as a result of the food we took into our +systems, but this belief was exploded when it was found that a really +tired person could hardly digest food while tired, and that it is best +for people who are very tired to eat only a light meal. + + + + +Why Are Most People Right-Handed? + + +Most people are right-handed because they are trained that way. Being +right-handed or left-handed depends largely on how we get started in +that connection. When we are young we form the habit generally of +being either right-handed or left-handed, as the case may be. Most +people correct their children when it appears they are likely to +become left-handed, as we have come to think that it is better to be +right-handed than left, and that is the reason why most people are +right-handed. As a matter of fact, if we were trained perfectly, we +should all be both right-handed and left-handed also. Some people are +so trained and, when we refer to their ability to do things equally +well with both hands and wish to bring out this fact, we say they are +ambidextrous. It is not natural that one hand should be trained to do +things while the other is not. + + + + +Why Are Some Faculties Stronger Than Others? + + +All of our senses are capable of being developed so that our ability +along these lines would be about equal. The trouble is that we soon +begin to develop one or more of our faculties in an unusual manner at +the expense of the development of others. Many people have a keener +sense of observation than others because they have had more and better +training along that line. It is a pity that more attention is not given +to the development of the power of observation in children, because +it is one of the most valuable accomplishments that we can possess +ourselves of. With the sense of observation developed to the highest +degree, many of the other faculties need not be developed so strongly +because, if we notice every thing that it is possible for us to see, +we do not have the need of the development of other powers to the same +extent. + +It is said that it would be possible to so train an infant and bring +him up to maturity with all his faculties developed and in practically +an even way. If we did that we would have a wonderfully intelligent +being. + +[Illustration: Glazing plates.] + +[Illustration: Decorating china cups.] + + + + +The Story in a Cup and Saucer + + +~HOW CHINA IS MADE~ + +Many different kinds of raw materials are required to produce the clay +from which china is formed, and these ingredients come from widely +separated localities. Clays from Florida, North Carolina, Cornwall and +Devon. Flint from Illinois and Pennsylvania. Boracic acid from the +Mojave Desert and Tuscany. Cobalt from Ontario and Saxony. Feldspar +from Maine. All these and more must enter into the making of every +piece. + +[Illustration: Grinders for reducing glazing materials.] + +These materials are reduced to fine powder and stored in huge bins. +Between these bins, on a track provided for the purpose, the workmen +push a car which bears a great box. Under this box is a scale for +weighing the exact amount of each ingredient as it is put in, for too +much of one kind of clay or too little of another would seriously +impair the quality of the finished china. + +[Illustration: Mill for pulverizing materials.] + +From bin to bin this car goes, gathering up so many pounds of this +material and so many pounds of that, until its load is complete. Then +it is dumped into one of the great round tanks called “blungers,” where +big electrically driven paddles mix it with water until it has the +consistency of thick cream. From the blungers this liquid mass passes +into another and still larger tank, called a “rough agitator,” and is +there kept constantly in motion until it is released to run in a steady +stream over the “sifters.” + +These sifters are vibrating tables of finest silk lawn, very much +like that used for bolting flour at the mills. The material for +china making strains through the silk, while the refuse, including +all foreign matter, little lumps, etc., runs into a waste trough and +is thrown away. From the sifters the liquid passes through a square +box-like chute, in which are placed a number of large horseshoe +magnets, which attract to themselves and hold any particles of harmful +minerals which may be in the mixture. + +After leaving the magnets the fluid is free from impurities, and is +discharged into another huge tank called the “smooth agitator.” While +the fluid is in this tank a number of paddles keep it constantly in +motion. + +[Illustration: Pressing the water from the clay.] + +From the smooth agitator the mixture is forced under high pressure into +a press where a peculiar arrangement of steel chambers packed with +heavy canvas allows the water to escape, filtered pure and clear, but +retains the clay in discs or leaves weighing about thirty pounds each. +From the presses this damp clay is taken out to the “pug mills,” where +it is all ground up together, reduced to a uniform consistency, and +cut into blocks of convenient size. It is now ready to use. Automatic +elevators carry it to the workmen upstairs. + +[Illustration: Molding Dishes. The racks to the left are full of molds +on which the clay is drying.] + +[Illustration: Molding sugar bowls and covered dishes.] + +~HOW THE DISHES ARE SHAPED~ + +The exact process of handling the clay differs with articles of +different shapes. Some are molded by hand in plaster of paris molds of +proper shape, while others are formed by machine. To make a plate, for +example, the workman takes a lump of clay as large as a teacup. He lays +this on a flat stone, and with a large, round, flat weight, strikes it +a blow which flattens the material out until it resembles dough rolled +out for cake or biscuits, only instead of being white or yellow it is +of a dark gray color. A hard, smooth mold exactly the size and shape +of the inside of the plate is at hand. Over this the workman claps the +flat piece of damp clay. Then the mold is passed on to another workman, +who stands before a rapidly revolving pedestal, commonly known as the +potter’s wheel. On this wheel he places the mold and its layer of clay. +He then pulls down a lever to which is attached a steel scraper. As the +plate rapidly revolves, this scraper cuts away the surplus clay, and +gives to the back of the plate its proper form. The plate, still in its +mold, is placed on a long board, together with a number of others, and +shoved into a rack to dry. One workman with two helpers will make 2,400 +plates per day. It is fascinating to watch the molders’ deft hands at +work swiftly changing a mass of clay into perfectly formed dishes. Such +skilled workmen are naturally well paid. + +[Illustration: Interior of a kiln showing how the “saggers” are packed +for firing.] + +When the clay is sufficiently dry, the plate is taken from its mold, +the edge smoothed and rounded, and any minor defects remedied. It +is then placed in an oval shaped clay receptacle called a “sagger,” +together with about two dozen of its fellows, packed in fine sand, +and placed in one of the furnaces or kilns. Each kiln will contain on +an average two thousand saggers. When the kiln is full the doorway +is closed and plastered with clay, the fires started, and the dishes +subjected to terrific heat for a period of forty-eight hours. The +fuel used is natural gas, piped one hundred miles from wells 2,000 +feet deep. Natural gas gives an intense heat, and yet is always under +perfect control--features which are vital in producing uniformly good +china. + +When the plate is taken from the kiln after the first baking, it is +pure white, but of dull, velvety texture, and is known as bisque ware. + +In order to give it a smooth, high finish, the plate is next dipped +into a solution of white lead, borax and silica, dried, placed in a +kiln and again baked. When it is taken out for the second time it +has acquired that beautiful glaze which so delights the eye. In this +condition it is known as “plain white ware,” and is finished, unless +some decoration is to be added. + +[Illustration: Taking the dishes from a kiln.] + +~HOW CHINA IS DECORATED~ + +Most people are surprised to learn that the greater part of the +gold which adorns dishes is put on by a simple rubber stamp. Two +preparations of gold are used. One is a commercial solution called +“liquid bright gold,” the other is very expensive, and is simply gold +bullion melted down with acids to the right consistency. + +Decorating in colors is now done almost exclusively by decalcomania art +transfers. These are made principally in Europe. + +After the gold and colors are applied, the China must again go through +the oven’s heat for a period of twelve hours. Then the piece finished +at last, is ready to grace your table. The dull gray clay has become +beautifully finished china, which will delight alike the housekeeper +and her guests. + + + + +How Do Birds Find Their Way? + + +The most interesting phase of the movement of animals from place to +place is found in the flight of birds during the spring and fall. In +the spring the birds come north and in the fall they go south. This is +called “migration” and the reason given for the ability of some birds +to come back every year to build a nest in the same tree is usually +attributed to the “instinct of migration,” and yet that is more a +statement of fact rather than an explanation of the wonderful ability +of the birds to do this. + + + + +How Does a Captain Steer His Ship Across the Ocean? + + +Man, the most intelligent animal, can also find his way about, but +he has had to learn to do this step by step. When an explorer first +travels into the unexplored forest, he carries a compass which tells +him in what direction he is traveling, but this is not sufficient to +tell him the exact path he came and return the same way. In order that +he may do this, he must make marks on the trees and other objects +to find his way back. When these marks are once made, other men can +follow the path by their aid, and eventually a path becomes worn so +that men can find their way back and forth without the aid of the marks +especially. + +A trained ship captain can take his ship from any port in the world to +another port. He can start at New York City and in a given number of +days, according to how fast his ship can travel, land his passengers +and cargo in the port of London or Johannesburg, South Africa, or at +any desired port in China, Japan or any other country. But he cannot do +this by any kind of instinct. He takes his directions from information +that was furnished him by some one who went that way before him--some +other captain of a vessel who made marks in his book of his position +in relation to the sun and stars. This is practically the same as the +traveler in the forest who made marks on the trees to make a map of the +way back and forth. Even with these charts, compasses and other guiding +marks, however, man, even though he is the most intelligent of all the +animals, makes very grave mistakes and sometimes brings disaster upon +himself and the lives in his care. + + + + +Why the Birds Come Back in Spring? + + +The birds, however, have no charts or compasses to guide them. We do +not know as yet absolutely what it is that enables the bird to find its +way back and forth to the same spot year after year. As nearly as we +have been able to ascertain, the birds after they mate and build their +first nest and bring up their first family, develop a fondness for that +particular spot which is much the same as the instinct in man which we +call the “homing instinct.” Man becomes attached to one particular spot +which he calls home and wherever he is thereafter, he is very likely to +think of the old locality when he thinks of home, and there are very +few of us but have yearnings to go back to the old “home locality” +every now and then. The environment in which a bird or human being is +brought up generally becomes to a greater or less extent a permanent +part of him in this sense. + + + + +Why Do Birds Go South in Winter? + + +We know why birds go south in the winter. The necessity of finding +food to live upon has everything to do with that. As food grows +scarce towards the end of summer in the farthest northern places where +birds live, the birds there must find food elsewhere. They naturally +turn south and when they find food, they have to divide with the birds +living there. The result is that soon the food becomes scarce again +and both the new-comers and the old residents, so to speak, are forced +to seek places where food is plentiful. So both of these flocks, to +use a short term, fly away to the south until they find food again +and encounter a third flock or group of the bird family crowding the +locality and exhausting the food supply. So in turn each flock presses +for food upon the one in the locality next further to the south until +we have a general movement to the south of practically all the birds +until they reach a point where the food supply is sufficient for all +for the time being. + + + + +Why Don’t the Birds Stay South? + + +The result of all this is that the south-land is crowded with birds of +all kinds and the food supply is enough for all. But soon in following +the laws of nature in birds, as in other living things, comes the time +for breeding. The south-land is warm enough for nesting and hatching, +but it is so crowded that there wouldn’t be enough food for all the old +birds and the little ones too and so the birds begin to scatter again. +Just think of what would happen in the south-land if all the birds that +stay there in the winter built their nests there and brought up a new +family. A bird family will average four young birds, so that if all the +bird families were born and raised in the south the bird population +would quickly multiply itself by three and there would be the same old +necessity of traveling away to look for food. To avoid this the birds +begin to scatter to their old homes before the breeding season begins. + + + + +How Do They Find the Old Home? + + +The return of the birds to their old homes and how they find their +way back to the same spot every year, to do which they must sometimes +travel thousands of miles, is one of the most marvelous things in +nature and has not as yet been satisfactorily determined. The nearest +approach we have to a satisfactory answer to this is that birds do have +a memory, that they can and do recognize familiar objects, and that +their love for the old home causes them to fly to the north until they +recognize the landmarks of their former habitation. In this it is said +that the older birds--those who have gone that way before--lead the +flocks and show the way. + +There is no doubt that birds have a more perfect instinct of direction +than man. They can follow a line of longitude almost perfectly, i.e., +they can pick out the shorter route by instinct, and this is, of +course, a straight line. They just keep on going until they come to the +familiar place they call home and then they stop and build their nests. +That it is not memory and sight of places alone that guides the birds +is shown by the fact that some birds when migrating fly all night when +there is no light by which to recognize familiar objects. + + + + +Why Do Birds Sing? + + +The song of the birds is a part of the love-making. The male bird is +the “singer,” as we call them at home, when we think of the canary in +the cage near us. The male bird sings to his mate to charm her and to +further his wooing. This wooing goes on after the eggs have been laid +in the nest and while the mother bird is keeping them warm until they +hatch out, but almost instantaneously with the birth of the little +birds, the song of the male bird is hushed. Take the case of the +nightingale. For weeks during the period of nest-building and hatching +he charms his mate and us with the beautiful music of his love song. +But as soon as the little nightingales come from the eggs, the sounds +which the male nightingale makes are changed to a gutteral croak, which +are expressive of anxiety and alarm, in great contrast to the song +notes of his wooing. And yet, if you were at this period--just after +the birds are born, and when his song changes--to destroy the nest +and contents, you would at once find Mr. Nightingale return to his +beautiful song of love to inspire his mate to help him build another +nest and start all over again to raise a family. + + + + +What Causes an Arrow to Fly? + + +It is caused by the power generated when you bend the bow and string +of the bow and arrow out of shape. The bow and string have the quality +of elasticity which causes a rubber ball to bounce. When you force +anything elastic out of shape, this quality in it makes it try to +get back to its natural shape quickly. In doing this it acts in the +direction which will take it back to its normal shape most quickly. The +arrow is fixed on the string in a way that will not interfere with the +bow and string getting back to its shape and, when they bounce back, +the arrow goes with it. The real cause for the arrow’s flight, however, +comes not from the bow, because the bow cannot put itself out of +shape, but comes from the person who causes it to be out of shape and, +therefore, the person who pulls the string back really causes the arrow +to fly. + + + + +Why Do Children Like Candy? + + +Children crave candy because the sugar which it contains largely is in +such a condition that it is the most suited of all our foods for quick +use by the body. It is actually turned into real energy within a few +minutes after it is eaten. + +All the things we eat are for the purpose of supplying energy to our +bodies to replace the energy that our daily activities have dissipated. +Nature takes the valuable parts of the foods we eat and changes them +into energy. The waste parts she throws off. Many things we eat have +little real value as food and many also nature has to work upon a long +time before their food value is available in energy. Sugar, however, +represents almost energy itself. + +Children are, of course, more active than grown-ups. They are never +still. They are, therefore, almost always burning up or using up their +energy. They are also, therefore, almost always in need of food that +can be made into energy, and as sugar does this almost more quickly +than any other food, nature teaches the children to like candy or +sweets. + + + + +Why Does Eating Candy Make Some People Fat? + + +Eating as much as one can of anything at any time will produce fat, +provided you do not do sufficient physical work or take enough exercise +to counteract the effect of generous eating. When you see a person who +eats a great deal and is growing fat, you may know that he or she is +not taking sufficient bodily exercise to work off the energy produced +by the body from the food that has been eaten. When this happens the +energy in the form of fat piles up in various parts of the system. +Candy will do this more quickly than any other thing we eat because it +contains so much sugar and because sugar is so easily changed by our +system into usable energy. You generally find a fat person who eats +much candy to be a lazy person. + + + + +What Makes Snowflakes White? + + +A snowflake is, as you are no doubt aware, made of water affected in +such a way by the temperature as to change it into a crystal. Water, of +course, as you know, is perfectly transparent. In other words, sunlight +or other light will pass through water without being reflected. A +single snow flake also is partially transparent, i.e., the light will +go through it partially, although some of it will be reflected back. +When a drop of water is turned into a snowflake crystal, a great many +reflecting surfaces are produced, and the whiteness of the snowflake is +the result of practically all of the sunlight which strikes it being +reflected back, just as a mirror reflects practically all the light or +color that is thrown against it. If you turn a green light on the snow, +it will reflect the green light in the same way. When the countless +snow crystals lie on the ground close together, the ability to reflect +the light is increased and so a mass of snow crystals on the ground +look even whiter than one single snowflake. + + + + +What Makes the White Caps on the Waves White? + + +In telling why the snowflake is white we have practically already +answered this question also. Instead of little crystals formed from the +water, the foam produced by the waves of the ocean are tiny bubbles +which have the same ability to reflect the light as the snow crystals. + + + + +What Good Can Come of a Toothache? + + +Very few of us realize that an aching tooth is a good thing for us, +provided we have it attended to and the ache removed. Any one who has +had toothache will hardly agree that there can be a blessing attached +to this excruciating pain. + +But the good comes from the warning it gives us of the condition of our +teeth on the inside of our mouths. The arrangement of the interior of +the mouth and the use we make of it in passing things into our systems, +favors very much the development and increase of microbes, and when +they once get in they are difficult to remove. It is said that the +greatest percentage of cases of stomach trouble come from teeth which +are in bad condition and that a very large percentage of people who +have bad teeth are in grave danger of blood poisoning or other troubles +due to the microbes. When these microbes lodge in the mouth, they find +conditions favorable to their development when there are bad teeth, and +spread through the system. + + + + +How Can Microbes Spread Through the Body? + + +The various parts of the body, including the gums, are connected by +a lymphatic tissue, which is practically a series of canals. If the +teeth are not properly attended to and kept in good condition, both as +to cleanliness and repair, the microbes or germs collect on the gums +and teeth, and increase in numbers. Soon the mouth is over-populated +with microbes and are pushed off the gums or teeth into the lymphatic +canals, where they succeed in developing a disease in your body. + +Now the ache in the tooth becomes a blessing very promptly if it +begins soon after the tooth begins to decay, because in that event the +dentist is visited and the tooth filled or pulled. Therefore, while +it hurts terribly, it might be well to remember that a toothache is a +timely warning of danger which, if not heeded, will likely develop into +something quite serious. + + + + +What Causes Toothache? + + +The ache comes when the tiny nerve at the heart of the tooth is +exposed to the air. When the tooth begins to decay, it starts to do so +generally from the outside, and after the decaying process has gone far +enough, it reaches the nerve in the tooth, which aches when exposed to +the air. The ache is the signal which the nerve sends to the brain that +there is an exposure and a cry for help. + + + + +Of What Use Are Pains and Aches? + + +All pains and aches are helpful in sounding a warning. A headache may +be the result of improper sleep and rest and, therefore, warns us to +take the needed rest or sleep. A pain in the stomach is only nature’s +way of telling us that we have been unwise in our eating and drinking. +As a matter of fact, short though our lives are, they would probably +be still shorter, on the average, if it were not for pains and aches, +because without these warnings we would never have sense enough to stop +doing the things we should not do if we lived normally. + + + + +What Causes Earache? + + +Earache is caused by the nerves in the ear being affected by something +either from within or without which produces a swelling of the parts +immediately adjacent to the nerves in the ear, and which press against +the nerves; as the nerves cannot go any place else they send a warning +to the brain that they are being crowded and pressed against. The pain +you feel is the nerve in the ear warning the brain that something is +wrong in the ear. + + + + +What Is Soap Made Of? + + +Soap is not a very modern product, although we have rarely read of soap +in olden times. As long ago as two thousand years, the Germans had an +ointment which was made in practically the same way as we now make +soap. A soap factory was engaged in making soap in France in 1000 A. D. + +Even before soap was manufactured, people knew that ashes of some +plants, when mixed with water, gave it a peculiar, smooth, slippery +feeling, and added to the cleansing qualities of water. Although they +did not know it, this was due to the soda of potash which was in the +ashes. Pure soda and potash both have excellent qualities for cleaning, +but are likely to injure the skin, and other things coming in contact +with them. + +Soap is made by boiling together oil or fat and “caustic” soda or +potash. Caustic soda is a substance made from sodium carbonate by +adding slaked lime to a solution of it. The slaked lime contains +calcium in combination with hydrogen and oxygen, and is known in +chemistry as calcium hydrate. When calcium hydrate is added to a +solution of sodium carbonate, the sodium present combines with the +oxygen and hydrogen to form a compound, variously called sodium +hydrate, sodium hydroxide, or caustic soda. A similar compound of +potassium is formed when the same kind of lime is mixed in a solution +of potassium carbonate. In both cases the calcium is converted into +calcium carbonate, which is not soluble in water and settles to the +bottom; but the caustic soda or potash is dissolved. + +The word “caustic” means to burn. Both will burn the skin if allowed to +touch the skin for a short time. + +The fats used for making soap consist of glycerine, in chemical +combination with what are called fatty acids. When these fats are +boiled with caustic soda, or caustic potash, the fat is decomposed; the +fatty acid combines with the sodium or potassium to form soap and the +glycerine is left uncombined. + +In modern soap factories the manufacture is carried on in large iron +vessels. Some fat and oil are put into the vessel and a little lye, +which is really caustic soda or potash, is added and the mixture +boiled. The fat and the lye combine very quickly and form a whitish +fluid. More lye is now added and the boiling continued. This process +is repeated until nearly all the oil or fat has combined with the lye. +If yellow laundry soap is being made, some rosin is put in, and this +gives the yellow color. If toilet soap is being made, common salt is +put in instead of rosin. The addition of the salt has the effect of +separating the water and the glycerine from the soap. The soap rises to +the surface and is skimmed off. As soon as the separation is complete, +and the soap is then cut or pressed into cakes after it has become hard. + +Soaps referred to above are the ordinary hard soaps. In making soft +soaps no salt is added to separate the soap from the liquid. As the +water and glycerine do not separate from the soap, the entire mixture +remains of a soft consistency. Soft soap is also made with a lye, that +is obtained from wood ashes. The ashes are placed in barrels and water +poured upon them. The water drips down through the ashes in the barrel +and dissolves the potash contained in them, making lye or caustic +potash. This lye is then in liquid form and is mixed and boiled with +grease or fat to make soap. + +There are many different fats used in soap making. Palm oil is perhaps +the most common, but tallow, olive oil, cotton seed oil, and many other +fats are used. The hardness of the soap varies with the kind of fat +and lye used. Palm oil or tallow soap is very hard, and other oils are +sometimes mixed with it to soften it. + +These are the main facts connected with the making of soaps. There may +appear to be different kinds all of which look and smell differently. +The difference in them is largely due to the presence of different +perfumes and coloring matters. + +[Illustration: INDIAN SENDING MESSAGE WITH SMOKE SIGNALS. + +The savage Indians found their system of smoke signals quite effective +in sending messages from place to place. With a good burning fire +before him, and a blanket or shield at hand, the Indian was equipped +to send his messages. The code consisted of the varying kinds of smoke +clouds produced. These were made large or small by covering the fire +at intervals with the blanket or shield, thus making interruptions of +various lengths in the rising clouds of smoke. By dropping moss or +other things into the fire, he made the smoke clouds either light or +dark at will.] + + + + +The Story in a Telegram + + +How Man Learned to Send Messages. + +From the time when man had learned to protect himself from the beasts +of the forest, and thus was able to move about more freely, and live by +himself rather than remain with the tribe, he has found it necessary to +send messages. + +One of the most interesting of the early methods for sending messages +was the Indian way of smoke signalling with the simple equipment of a +fire with its rising column of smoke and a blanket or shield. Messages +were sent, relayed, received and answered, at points hundreds of miles +apart. Among savages still found in remote parts of the earth this and +other primitive methods are still in use. In the wilds of Africa to-day +at points where the electric telegraph service has not yet penetrated, +the natives by the simple method of beating drums, which can be heard +from one relay point to another, are able to send the “news of the day” +across the country with marvellous rapidity. In some parts of South +America, the natives long ago discovered that the ground is a good +conductor of sound and send their messages almost at will, making their +signals by tapping against poles which they have planted in the ground +at various points and which constitute both their sending and receiving +instruments. + +The Signal Corps in the army uses flags for sending messages, where +the telegraph is not available, the flags being of different colors, +and the signals are produced by waving the flags in different ways. +The army heliograph is also used as a telegraph line--a mirror which +reflects the sun’s rays in a manner understood by a prearranged code. +These and other similar methods are merely elaborations of devices +developed and used by the savages as a solution of the ever present +need of sending a message to some other point. + +[Illustration: THE FIRST MESSENGER BOY + +THE GREEK RUNNER. + +In this picture we see the Greek Runner on the last leg of his journey +and the man to whom he is to deliver the message waiting for him. This +method of sending messages was not very fast, although the runners were +picked because of their speed and endurance.] + +[Illustration: THE PONY TELEGRAPH. + +Here we see the fast riders of the Pony Telegraph, which increased the +speed of delivering messages quite a good deal, but, of course, there +was danger of losing the message to enemies or through accident, so +that it might be difficult under such circumstances to send a secret +message or to even be certain that it would arrive at destination.] + +[Illustration: IT IS EASY TO CALL A TELEGRAPH MESSENGER... + +RINGING THE CALL BOX.] + +The great Marathon runner was nothing more or less than a telegraph +messenger hastening with his written message, from the man who +delivered it to him, to its destination, and his work was harder than +that of the messenger boy to-day, for he not only had to deliver the +message himself to its destination, but had to run fast all the way or +lose his job. + +The messenger on foot finally gave way to the Pony Telegraph, which not +only shortened the time necessary to deliver a message, but marked the +beginning of a system. + +[Illustration: MESSENGER BOYS WITH BICYCLES WAITING THE CALL.] + + +How Does a Telegram Get There? + +The next time your daddy takes you down to the office, ask him to show +you the telegraph call box. When you see it, you will perhaps not think +that by merely pulling down the little lever you can so start things +going that, if you wish, you can cause men who are on the other side +of the earth to work for you in a few minutes, and to make little +instruments all along the way which, with their other equipment, have +cost millions of dollars, click, click, click at your will. + +[Illustration: ...BUT MANY TELEGRAPH EMPLOYEES MUST WORK... + +Here we see the messenger calling at the office from which the call box +registered a call and receiving the telegram to be taken by him to the +central office to be put on the wire.] + +[Illustration: When the messenger gets back to the office, he hands the +message to the receiving clerk who stamps it, showing the exact time +received and sends it by pneumatic tube to the operating room.] + +Sooner or later during the day your father will be wanting to send a +telegram. He steps to the call box, pulls the little lever and goes +back to his desk. In a few minutes, sometimes before you realize it, +the little blue-coated messenger appears and says “Call?” Father +hands him a telegraph blank on which he has written the message, the +messenger takes off his cap, puts the message inside and the cap back +on his head and away he goes on his bicycle as fast as his legs can +pedal, to the central office, to which point you follow him to see what +he does with the message. + +If you had been at the telegraph office instead of your father’s +office, you would have seen one of these boys start off on his wheel to +get the message your father wished to send. When the little lever on +the call box is pulled down, it is pulled back by a spring which sets +some clock work going which sends a signal over the wire on a circuit +which runs out from a register at the main office. The register has a +paper tape running through it, and the signal from the call box appears +as a series of dots on the tape. The clerk knows from the number and +spacing of the dots that it was your father that called and not some +other business man whose box might be on the same circuit. + +[Illustration: ...BEFORE THE TELEGRAPH SERVICE IS POSSIBLE AND... + +We have now followed the telegram to the point where it is to start +on its real journey. Here we see the operator preparing to send the +message. He first must “get the wire.” By this is meant to get a +through connection to the town where the message is to be delivered. +Each office along the line has a signal. The other operators can hear +the call, but since it is not their signal, they pay no attention. +Almost immediately, however, the operator at the delivery point hears +the signal. He signals back “I I” and repeats his own office call, +which means “I hear you and am ready.” The message is then ticked off, +until finished and the operator at the delivery point signals “O. K.,” +together with his personal signal, which means he has received the +whole message and has it down on paper.] + +[Illustration: Here we see the operator at the delivery office. She +has translated the dots and dashes as they came to her over the wire +into plain words on a regular telegraph blank, putting down the time +received, the amount to be collected, if it is a “collect” message, or +marking it “Paid” if it was so sent. She has handed it to one of the +blue-clad messengers in her office who starts off at once to deliver +it. The operator has also made a copy of the message for the office +files.] + +[Illustration: ...THE TELEGRAM ARRIVES AT DESTINATION + +Here we see the messenger delivering the telegram to the person to +whom it is addressed. It may be good news or bad news for the person +receiving it, but it is all in the day’s work for the messenger boy. +But let us see how many people have to work to deliver the message. We +have followed it through from the original call box. First there was +the messenger who came for it, then the receiving clerk, the sending +operator and the operator who receives it and last of all the messenger +boy who delivered it. This does not take into account the men who must +look after the many miles of wires, the machinery which supplies the +current, or the great army of men who are constantly laying new wires +so that you can send a telegram from almost anywhere to any other +place.] + +The operators you have seen working in these pictures are Morse +operators. They send the message by Morse Code in dots and dashes +which are sent over the wire as electric impulses. At the other end +the message is read by listening to the clicks the sounder makes as +it receives these same electric impulses. This is the simplest way of +telegraphing. + +The number of messages sent between two big cities in a day is +tremendous--many more than could be transmitted over one Morse wire. +Many wires would be needed. But wire costs money, so ingenious men +set to work to find some way to send more than one message over a +single wire at the same time. They succeeded. There is now the duplex +telegraph, which sends a message each way simultaneously over a single +wire, the quadruplex, which sends two messages each way simultaneously +over a single wire. Last but not least there is the multiplex, which +sends four messages each way simultaneously over a single wire. +This seems almost unbelievable, but it is done. In the case of the +duplex and quadruplex, the different messages are sent by currents +of different strength, and by changing the direction of the current. +Receiving instruments are designed so as to separate the messages by +being affected only by the currents of certain strength or polarity, +as the direction of flow is termed. It can easily be seen that by +these ingenious devices, the telegraph company saves many thousands +of dollars in the miles and miles of wire, and hundreds of telegraph +poles which would be required if all the messages had to be sent over a +simple Morse wire, one message only upon the wire at a time. + +[Illustration: THE WONDERFUL ELECTRIC TELEGRAPH SYSTEM... + +In this picture we see the interior of a telegraph office along the +line of a railroad. The operator has her hand on the “key” or sending +instrument. At her left in a stand called the resonator, is the +receiving instrument called the “sounder” which clicks off the message. +In front of her is an instrument called the “relay.” Current from two +of the batteries goes through the key when it is pressed down, through +the relay and out on to the wires of the pole line, then through the +relay of the receiving operator at the other end, (see picture on +opposite page) through his key and through two more batteries to the +ground. The earth forms the return wire of an electric circuit when +both keys are “closed” or pressed down. You know all electricity has to +flow in a closed circuit. The “sounder” has to make good strong clicks +to be understood, and the current after it has gone through miles of +wire and ground may not be strong enough so the sounder is put on a +local circuit of its own, with a special battery. In this circuit is a +contact maker which is part of the relay. When the key is pressed down +and current flows over the wires on the poles and through the relays, +the magnets of the relay pull on a little piece of metal called the +“armature,” which makes a contact and closes the local sounder circuit, +so current from the single local battery can flow up through the +magnets of the sounder and back to the battery. This makes the sounder +click. When the key is released, the relay armature is pulled back by +a spring and breaks the circuit of sounder, which then emits another +click. By the number and duration of the clicks and the time between +them, the receiving operator knows the meaning of the signal. The Morse +Code, which is used throughout the United States, is shown on next +page.] + +[Illustration: ...SENDS MESSAGES THOUSANDS OF MILES INSTANTANEOUSLY + + MORSE TELEGRAPH CODE + + Letters Morse + A · -- + B -- · · · + C · · · + D -- · · + E · + F · -- · + G -- -- · + H · · · · + I · · + J -- · -- · + K -- · -- + L ---- + M -- -- + N -- · + O · · + P · · · · · + Q · · -- · + R · · · + S · · · + T -- + U · · -- + V · · · -- + W · -- -- + X · -- · · + Y · · · · + Z · · · · + & · · · · + + Numerals + + Figures Morse + 1 · -- -- · + 2 · · -- · · + 3 · · · -- · + 4 · · · · -- + 5 -- -- -- + 6 · · · · · · + 7 -- -- · + 8 -- · · · · + 9 -- · · -- + 0 ---- + + Punctuations + + . Period · · -- -- · · + : Colon -- · -- · · + ; Semicolon · · · · · + , Comma · -- · -- + ? Interrogation -- · · -- · + ! Exclamation -- -- -- · + - Fraction Line · + ¶ Paragraph -- -- -- -- + () Parenthesis · -- ·· --] + +The multiplex telegraph is truly a marvellous invention. It has been +developed by the engineers of the Western Union Telegraph Co. working +with the engineers of the Western Electric Company. The principle +on which this instrument works is that if separate instruments are +given connection with the wire one after the other during very short +intervals of time, the effect is as though the wire were split up, and +each instrument works just as if it alone were on the wire. Not only +does the multiplex telegraph thus send four messages in one direction +and four messages in the opposite direction, simultaneously over a +single wire, thus keeping no less than sixteen operators employed on +one wire, four sending and four receiving at each end, but each message +instead of being sent by the ordinary Morse key, is written upon a +typewriter keyboard at one end of the line and appears automatically +typewritten at the other end. + +If you live in a big city, go into one of the larger branch offices +of the Western Union Telegraph Co. and ask to see printing telegraph. +Most of the large branch offices communicate with the general operating +department in the city by means of what they term “short line +printers,” which are instruments on which the message is written upon a +typewriter keyboard and appears typewritten at the other end. + + +Who Invented the Electric Telegraph? + +It is hard to say just how the telegraph originated in the mind of men. +We have already shown how the savages sent signals over distances by +means of the smoke rising from his fire. Every boy and girl has used a +little mirror, held in the sun to flash a bright spot here and there. +This principle has been used by the army to signal at distances. The +sun’s rays are flashed from a small mirror, long and short flashes +indicating the dashes and dots of the Morse telegraph code. + +[Illustration: PROFESSOR S. F. B. MORSE, INVENTOR OF THE TELEGRAPH.] + +Progress towards the perfection of the electric telegraph began with +the first researches of scientists into the natural laws which govern +that great natural agent, electricity. Clever, painstaking men, +studying and experimenting for the love of the work, discovered bit +by bit how to control the force. Stephen Gray with his Leyden jars, +which stored up a charge of electricity, inspired Sir William Watson to +experiment, and he sent current from one jar to another two miles away. + + +The First Suggestion of the Electric Telegraph. + +For a long time no one thought that this opened the way for the making +of a useful servant for man. In 1753 this thought occurred to an +unknown man in Scotland, who wrote a letter to a newspaper suggesting +that messages be sent by electric currents. + +One of his schemes was that there should be a light ball at the +receiving end of the wire which would strike a bell when it felt +the electric impulse come over the wire from the Leyden jar, and by +devising a code depending upon the number of strokes of the bell and +the time between them, he suggested that messages could be sent and +interpreted. Some believe this man to have been a doctor named Charles +Morrison of Greenock, Scotland. Whoever he was, he suggested a method +which comes very near to being that in use to-day. + +The difficulty with proceeding on this suggestion was that the current +from the Leyden jar was static electricity, which has not the strength +nor can it be controlled as can the current of low potential which +is used to-day. Volta discovered this new and more stable form of +electricity and many different men labored investigating what could +be accomplished with it. The names of Sir Humphry Davy and Michael +Faraday are inseparably connected with this advance. It was Oersted’s +and Faraday’s discovery of the connection between electricity and +magnetism, and how an electric current may be made to magnetize a piece +of iron at will, that really opened the way for the invention of the +telegraph we know to-day. + + +The First Real Telegraph. + +But before the much greater practical value of Volta’s current was +discovered, one man developed a real telegraph which worked with +electricity of the static kind, produced by friction. This man was +named Sir Francis Ronalds. He worked along the lines laid down by the +unknown Scotchman, whom we have supposed to be Charles Morrison. The +machine he built and operated in his garden at Hammersmith utilized +pith balls, which actuated by the charge of static electricity sent +along the wire caused a letter to appear before an opening in the dial. +When perfected he offered it to the British Government, who refused +it. They were very stupid in their refusal, for they said “telegraphs +are wholly unnecessary.” Sir Francis Ronalds’ invention cost him much +care, anxiety and money. He lived to see the more practical voltaic +current taken up by others and put to successful use. Being unselfish +he rejoiced that others should succeed where he had failed. + + +Two Men who Invented our Telegraph almost Simultaneously. + +The telegraph, working on the electro-magnetic principle, as used +to-day, was developed almost simultaneously on the two sides of the +Atlantic Ocean. In England Sir Charles Wheatstone and Sir William +Fothergill Cooke worked out a practical method and instruments, which +with few changes, are in use to-day. Cooke was a doctor and had +served with the British army in India. Wheatstone was the son of a +Gloucester musical instrument maker. The latter was fond of science and +experimented continually with electricity and wrote about it and other +scientific subjects. As a result of his work he was made a professor +at King’s College. There he conducted important researches and tests, +among which was one which measured the speed at which electricity +travels along a wire. So Cooke, who was a doctor and a good business +man, entered into partnership with the scientist Wheatstone, and +together they completed their invention. It was first used in 1838 +on the London and Blackwall Railway. At first it was expensive and +cumbersome, using five lines of wire. Later this number was reduced +to two, and in 1845, an instrument was devised which required but one +wire. This instrument, with a few minor changes, is the one in use +to-day in England. + +While these two men were working in England, an American artist, S. F. +B. Morse, was studying and experimenting in the United States along his +own lines but with the same end in view, namely to produce instruments +which would satisfactorily send messages over a wire by electricity. + + +An American, however, is given the honor of First by Slight Margin. + +Morse was born in Charlestown, Massachusetts, in 1791. He was gifted as +an artist, both in painting and sculpture, and in 1811 went abroad to +England to study. While on a voyage from Havre to America in 1832 he +met on board ship a Dr. Jackson, who told him of the latest scientific +discoveries in regard to the electric current and the electro-magnet. +This set Morse to thinking and after three years’ hard work on the +problem he produced a telegraph which worked on the principle of the +electro-magnet. With the apparatus devised by Morse and his partner +Alfred Vail, a message was sent from Washington to Baltimore in 1844. + +There has been some question as to whether Morse or Wheatstone first +invented a workable telegraph. As will be evident from this history, +the telegraph in principle was a gradual development, to which many +minds contributed. To Morse, however, the high authority of the +Supreme Court of the United States has given the credit of being +the first to perfect a practical instrument, saying that the Morse +invention “preceded the three European inventions” and that it would +be impossible to examine the latter without perceiving at once “the +decided superiority of the one invented by Professor Morse.” + + +Uncle Sam Helped Build the First Telegraph Line. + +~FIRST TELEGRAPH LINE FROM BALTIMORE TO WASHINGTON~ + +At the time Morse’s Recording Telegraph was invented there were, of +course, no telegraph lines in any part of the world, with the exception +of the short lines of wire put up by investigators for experimental +purposes. To remove the obscurity as to the purpose to be served by the +telegraph was the first problem which presented itself to Morse and his +backers. In 1843 an appropriation was secured of $30,000 from the U. S. +Government, with which a line was built from Washington to Baltimore. +This was built and operated by the Government for about two years, but +the Government refused to purchase the patent rights. So the owners +of the patents endeavored to get the general public interested in the +telegraph as a commercial undertaking and gradually companies were +founded and licensed to use the invention. + +By 1851 there were as many as fifty different telegraph companies in +operation in different parts of the United States. A few of these +used the devices of a man named Alexander Bain, which were afterwards +adjudged to infringe the Morse patents, and one or two used an +instrument invented by Royal E. House of Vermont, which printed the +messages received in plain Roman letters on a ribbon of paper. This at +first seemed to have an advantage over that of Morse, which received +the message in dots and dashes, in the Morse Code, and these had +to be translated and written out by an operator before they could +be delivered. However, as time went on, the operators came to read +the Morse messages by the sound of the dots and dashes, instead of +waiting to read the paper tape having the dots and dashes marked on +it, and finally the recording feature was given up and the sounder, or +instrument which simply clicks out the message, came into general use. + +In the early days, the possibility of the business were little +understood and many telegraph companies failed. April 8, 1851, +papers were filed in Albany for the incorporation of the New York +and Mississippi Valley Printing Telegraph Co. This company, which +soon afterwards changed its name to Western Union, was destined to +absorb the various companies throughout the country until it, in time, +operated the telegraph lines over practically the entire United States, +and has its blue sign in nearly every town and hamlet in the country. + +[Illustration: AN EXPENSIVE EQUIPMENT NECESSARY TO-DAY + +OPERATING ROOM. + +In large cities like New York and Chicago, the operating rooms are very +large. For instance, the main operating department of the Western Union +Telegraph Co. in New York City has 1000 operators. This picture shows +an operating room. The men and women sit in opposite sides of long +tables. On the tables are the keys and sounders by which they send and +receive the messages. Each operator has a typewriter, or “mill,” as he +calls it, on which he writes off the message as it comes to him over +the wire.] + +[Illustration: MAIN SWITCHBOARD. + +The picture shows a main switchboard in a large operating room. To this +come the ends of the wires from other cities, and to it are connected +the wires from the instruments in front of the operators. By putting +plugs, attached to each end of a wire, into the sockets in the board, +any wire can be connected with any operating position, or several local +circuits can be connected up with a main line from the outside.] + +[Illustration: A THOROUGH SYSTEM MUST HANDLE THE MESSAGES + +A SECTION OF THE REPEATER ROOM. + +When a wire runs to a distant point from the main operating department +of the telegraph company in a large city, the same electric current +which runs through the key of the operator as he sits at his place, +busily sending messages, does not go out over the wire to that distant +point. It simply goes to the repeater room and operates a repeater, +which sends out another current over the long wire which leads to the +destination of the message. This is necessary because the condition +of the weather affects the lines and the current strength has to be +changed to suit the changing line conditions. The operators haven’t +time to make these adjustments, and so all the repeaters are grouped +together in the repeater room where they are under the watchful eyes +of experts. Here also are the delicate instruments which separate the +messages coming over duplex and quadruplex wires, by responding to +impulses of various strengths. These messages which have been separated +are then transmitted by the duplex or quadruplex repeaters to different +operators in the operating room, who hear their sounders tick out the +message just the same as if it came over a simple Morse wire.] + +[Illustration: CABLES ENTERING A CENTRAL OFFICE. + +You may not but your father will remember the time when in large cities +there were tall telegraph poles with hundreds of wires on them running +along the main streets, so that the town seemed to be bound with great +spiders’ web. That is all changed now, and the telegraph wires are run +through ducts, placed underground. For this purpose they are made up +in cables, and in the picture you see a number of cables entering a +central office.] + +[Illustration: THE MARVEL OF TELEGRAPH INSTRUMENTS + +WHEATSTONE SENDING INSTRUMENT. + +These two photographs show the most modern form of the instruments +which, as we are told on another page, were invented in England by +Wheatstone and Cooke. In sending a paper tape is punched in what +is called a perforator, which has a keyboard like a typewriter. A +certain combination of holes means a certain letter. This tape is then +automatically fed through the sending instrument, which sends impulses +over the wire. The tape with the holes punched through it can be seen +in the picture. + +On the right is the Wheatstone receiving instrument. It prints the +signals received in dots and dashes on a tape, which is translated by +the operator who typewrites the translation on a message blank for +delivery.] + +[Illustration: The automatic telegraph typewriter shown here is one of +the wonderful instruments mentioned on one of the preceding pages. The +operator at the other end of the line writes on a typewriter keyboard, +on the sending instrument. The electric impulses are received by the +machine shown above, which automatically typewrites the message on a +blank, ready for delivery.] + +On this page we see some of the first telegraph instruments, in +fact, the very instruments which Professor Morse used in the early +demonstrations of his invention. These instruments may be seen in the +Smithsonian Institution at Washington, D. C. The key is known as the +Vail key, because it is supposed to have been constructed by Alfred +Vail, who worked with Morse in his experiments with the telegraph. As +can be seen it is very simple. One wire was connected to the spring +piece and the other to the post beneath it. When the key was pressed +down, the contact was made and an impulse sent over the wire, either a +dot, if the key was pressed down and immediately released, or a dash if +it were held down for just the fraction of a second before releasing. + +From the very first it was found that relays were necessary, because +the current after coming a long way over the wire often was not +strong enough to operate the recording instrument. Therefore, this +weak current was made to go though the electro-magnets of the relay, +magnetizing these and pulling to the left the upright arm which can be +seen in the photograph with a little block of iron attached to it. This +arm, when pulled by the magnets, made a contact at the top and allowed +a strong current from a battery to flow through the magnets of the +recording instrument. + +The first practical recording telegraph instrument devised by Morse +is shown. It looks like a clumsy affair compared to the instruments +of to-day, but it worked so effectively as to convince people of the +possibilities of the great invention. In the wooden box, attached to +the frame at the right, is clockwork which pulled a paper tape at an +even rate of speed over a pulley just beneath a needle point. This +needle point is attached to a light framework having a piece of iron +fastened in it. Below this iron are the electro-magnets, and when they +received an impulse of current from the battery, through the relay, +they pulled down the frame so that the point made a mark upon the paper +tape which moved under it. Thus in the tape appeared a series of dots +and dashes, which the operator, knowing the Morse Code, could easily +translate into English. + +[Illustration: THE FIRST TELEGRAPH INSTRUMENTS + +ONE OF THE FIRST KEYS FOR SENDING TELEGRAMS.] + +[Illustration: ONE OF THE FIRST RELAYS.] + +[Illustration: The first recording apparatus. The box on the right +contains clock work for pulling a paper tape beneath a sharp point +actuated by magnets.] + +[Illustration: THE LITTLE INSTRUMENTS THAT CHECK OFF THE WORDS + +A LATER KEY.] + +[Illustration: A LATER AND IMPROVED RECORDING INSTRUMENT. + +Here we see some early telegraph instruments which have been improved +somewhat from the crude devices illustrated on the preceding page. +The key answers the same purpose as before, but has been improved by +pivoting the lever arm, and having a coil spring, adjustable by means +of a screw, so that the weight necessary to press it down can be varied +to suit the likings of the operator who uses it. The play of the key +or the distance it must be pressed down before it makes an electric +contact, can be adjusted by another screw. + +The recording instrument here shown is a much neater affair than the +cumbersome device which Professor Morse first built. The cumbersome +wooden box has been replaced with a neat brass frame containing the +clockwork for drawing the paper tape beneath the marking point, which +is attached to a piece of iron, or armature, placed just above the +magnet. + +Below we see the most modern types of Morse instruments. In the center +is the key, which is not much changed except that it is built to be +low down to a table, so that the operator may rest his forearm on the +table top in front of it, and operate the key with his wrist, with less +fatigue. The relay at the left is interesting. It shows how little this +instrument has changed, except for refinement in its appearance, from +the first relay built by Professor Morse. At the right is the Morse +sounder, which has replaced the old Morse tape recording instrument. +When current goes through the magnets they attract a piece of iron +attached to the metal arm and pull it down to strike the brass frame. +This makes a click, and when the current is intercepted, the magnets +release the arm and a spring pulls it back, making another click. The +operator reads the message by listening to the clicks. If the up click +comes right after the down click it represents a dot. If there is a +pause between them, a dash is represented.] + +[Illustration: + + Relay + + Key + + Sounder + +MODERN MORSE INSTRUMENTS] + +[Illustration: WHAT OCEAN CABLES LOOK LIKE WHEN CUT IN TWO + + _Light Intermediate_ + + _Heavy Intermediate_ + + _Main Cable_ + + _Rock Cable_ + + _Heavy Shore End_ + + _Rock Cable_ + + _Heavy Shore End_ + + _Heavy Intermediate_ + + _Light Intermediate_ + + _Deep Sea_ + + _Bay Cable_ + +FIG. 1.--CABLES ON VANCOUVER-FANNING ISLAND SECTION. + +Full size. + +Core, 600/340.] + +[Illustration: + + Yarn Serving & Compound + + 16 No. 13 (·095) Galvanized Wires + + Jute Serving + + Gutta Percha + + Copper Conductor + +FIG. 2.--CABLES USED ON FIJI-NORFOLK ISLAND-QUEENSLAND AND NEW ZEALAND +SECTIONS. Full size. Core 130/130. + +This picture shows cross-sections of a cable which runs from Vancouver, +B. C., to Australia and New Zealand. A cable is not laid with a +uniform cross-section. On the floor of the ocean, perhaps miles below +the surface, the cable rests quietly and is not moved by storms +which generate great waves on the surface of the water. As the cable +approaches the shore, the movement of the water goes deeper and the +cable must be made heavier to prevent it from being worn by movement on +the bed of the ocean. Where the cable passes over a rocky bottom, it is +made much larger in diameter and is heavily armored.] + +[Illustration: Here is the cable steamship “Colonia” laying the shore +end of a cable. Note the row of floats upon the water which carry the +cable until the end in the cable office is firmly fastened. When this +is accomplished the floats are removed and the cable sinks to the +bottom.] + + + + +The Story in an Ocean Cable + + +What is a Cable Made of? + +A submarine telegraph cable as usually made consists of a core in the +center of which is a strand of copper wire which varies in weight from +seventy to four hundred pounds to the mile. Strands of copper wire +instead of one thick wire of copper are used, because the former is +more flexible. The copper conductor is covered with several coatings of +rubber of equal weight to the copper wires. After this comes a coating +of jute serving, then a layer of galvanized iron wires and finally a +layer of yarn and compound which forms the outer covering of the cable. +In addition to this where the cable lays among rocks that might injure +it, chains are securely wrapped around it, so as to prevent wear and +tear as much as possible. + +You may not have known it, but the cable which lies on the bottom +where the water is deepest is never so large as nearer the shore or +in shallow water. Little by little the men who lay and look after +cables have found that it is best to have a specially constructed outer +covering for different depths and character of bottoms so as to provide +the least possible danger of damage through the action of the water on +the bottom. + + +How is a Cable Laid? + +When the cable of sufficient length is completed, it is carried to +a specially equipped vessel which has a great tank for holding the +cable and the necessary machinery for lowering it over the end of the +ship into the water. The cable is carefully coiled in the tank, the +different coils being prevented from adhering by a coat of whitewash. +First then, a sufficient length of cable is paid out to reach the cable +house or shore. Here it is finally tested to see that the entire length +of cable is in working order. If satisfactorily tested, the vessel +steams slowly away on the course outlined, paying out the cable as she +goes. + +[Illustration: STORING A CABLE LONG ENOUGH TO CROSS THE OCEAN + +Here we see a cable coiled round and round in the tank which holds it +on board the cable ship.] + +[Illustration: In the front of the picture we see the cable coming from +the tank in which it is coiled. It goes over the drum of the paying-out +machine and thence to the bow of the ship, where it passes over big +sheaves or pulleys and down into the ocean.] + +[Illustration: THE MACHINERY ON A CABLE SHIP + +The paying-out machine. The cable makes a couple of turns around the +big drum, which is connected to the dial, so that the dial indicates +the length of cable which has been paid out into the sea.] + +[Illustration: The upper forward deck of the cable steamship +“Telconia,” showing the gear which is used in paying out the cable. +Away in the bow are the big sheaves over which the cable goes into the +sea. Nearer is a dynamometer which measures the tension on the cable.] + +[Illustration: HOW THE CABLE IS DROPPED INTO THE OCEAN + +Here we see the cable on the lead, as it is called, passing over the +big bow sheave from which it dives into the depths of the sea.] + +The vessel must pay out more than a mile of cable for every mile she +travels because there must be enough slack allowed at the same time +to provide for the unevenness of the bottom of the sea. For this +purpose the amount of cable paid out must be measured. This is done +by the paying-out machine, which is shown in one of the pictures. +The difference between the speed of the ship and the amount of cable +paid out gives the amount of slack. Too much slack would also be bad, +so that it is a very pretty problem to pay out just enough and both +the speed of the vessel and the rate of paying out the cable must be +watched carefully. + +One of the greatest wonders accomplished by the ingenuity of man is the +ocean telegraph, by which we flash messages back and forth under the +sea between the continents and completely around the world. + +Hardly had the telegraph become an established fact, before Professor +Morse, who made the telegraph practical, expressed the belief that a +telegraph line to Europe by means of a wire laid on the bottom of the +ocean was easily possible at some future time. Mr. Cyrus W. Field, the +first to lay an ocean cable successfully, heard him and in his own +mind said “Why not now?” The idea fixed itself so thoroughly in his +resolute mind that he soon said to himself “It shall be done,” and +went to work, and labored incessantly through twelve years of failure +and discouragement before he accomplished his task, which was a great +compliment to this giant of American stick-to-it-iveness. + +While many doubted the feasibility of the project and others thought +it the dream of a disordered brain, Mr. Field found many who believed +in him and his idea and who loaned him their financial support for the +undertaking. + +[Illustration: THE CABLE ARRIVES ON THE OTHER SIDE + +Landing the shore end of a cable. The cable is supported on several +boats and this picture shows the inshore boat with the end of the cable +reaching the beach with the seas breaking over her.] + +[Illustration: THE MEN WHO MADE THE OCEAN CABLE POSSIBLE + +THE PIONEERS OF THE FIRST OCEAN CABLE.] + +American genius had not at that time asserted its supremacy in +mechanics and so the first cable had to be made in England; so Mr. +Field ordered one long enough to stretch from the west coast of Ireland +to the eastern point of Newfoundland. English capitalists subscribed +the money and the United States provided the vessel in which to store +and from which to drop the cable into the ocean. + +Upon the first attempt to lay the cable, every thing went along nicely +for six days, and then suddenly the cable broke when three hundred and +thirty-five miles had been laid, and many said it could not be done. +Mr. Field, however, full of American pluck and determination, said “We +will try again.” A second attempt was made with two ships, the U. S. S. +“Niagara” and H. M. S. S. “Agamemnon.” Each ship carried half the cable +and they traveled in company to the middle of the ocean. There the two +pieces of the cable were spliced together and the ships started for the +shores in opposite directions. Again, however, when only a little of +the cable had been paid out--a little more than one hundred miles in +fact--the cable broke and both ships were forced to return to England. + +In his third attempt the cable was finally laid clear across the +ocean and fastened at both ends. When tried it was found to work +successfully and Queen Victoria and President Buchanan were able to +exchange greetings upon the achievement of a wonderful work. The people +celebrated the event on both sides of the ocean, but in the midst of +the festivities, while a message was being flashed, something happened +to the cable--what, we have never been able to learn--and the cable was +silent, forever. + +Nothing daunted, however, Mr. Field by his great courage induced his +backers to buy him another cable and the “Great Eastern” sailed upon +what was to be a most successful mission. Starting from the American +side with the greatest steamship then known in charge of the previous +cable, the other end was successfully landed at Hearts Content, +Ireland, on July 27, 1866, in perfect working order, and the question +of the ocean telegraph was solved. + +[Illustration: HOW CABLES ARE REPAIRED + +Here is a buoy which is anchored to the cable. The cable ship will pick +it up and haul up the cable to the surface for inspection and perhaps +it will have to be repaired.] + +[Illustration: Three grapnels used for picking up a cable from the +bed of the ocean. On the left is a common grapnel. In the middle is a +special grapnel known as Trott-Kingsford. On the right is the ordinary +cutting grapnel. Note the knives on the shaft and the insides of the +prongs.] + +[Illustration: In this picture we see a portion of a cable which has +been fouled by the anchor of a ship and badly damaged. Note how the +wires are bunched. The cable splicers will go to work on this and put +in a new piece of cable, after which it will be let down into the sea +again.] + +[Illustration: The Western Union Cable ship “Minia,” fast in an ice +field.] + +[Illustration: POWERFUL ENGINES NEEDED ON CABLE REPAIR SHIPS + +Here are the powerful engines which are used for picking up a cable +which has to be raised from the bottom of the sea for inspection or +repair.] + +[Illustration: In this picture we see men at work splicing a cable +which has been picked up out of the depths of the sea and found to be +damaged.] + +[Illustration: THE SHIP WHICH HELPED IN LAYING THE FIRST CABLE + + ARMORING MACHINE + +Here is one of the machines used for armoring the cable. By armoring +is meant winding steel wires around and around the cable to protect it +from being cut by sharp rocks on the bottom or by deep sea animals like +the teredo, which might attack it.] + +[Illustration: The “Great Eastern” which was the first ship to carry a +cable across the Atlantic Ocean.] + +[Illustration: This is a section of a telephone cable, known as a +“bulge.” It contains inductance coils to offset what is called the +condenser capacity of the cable, which would otherwise cause the +talking to become blurred.] + +[Illustration: THE DOTS AND DASHES WHICH FLASH ACROSS THE SEA + +CONTINENTAL MORSE CODE SIGNALS USED IN CABLE WORKING] + +Making repairs to a cable where it comes out of the sea on to a bold +rocky shore. Note how the cable is wound with chain to protect it from +the rocks. + +[Illustration: Facsimile of Continental Morse Alphabet as Signalled +Across the Atlantic and Copied on Tape by Siphon Recorder Instrument +at the Receiving Station. Signals Enlarged for Purposes of this +Illustration. + +Same Signals as They Appear in Actual Working + +Here are two photographs showing the continental Morse code signals +used in cable working and the signals as they are received by the +siphon recording instrument at the receiving station. This siphon +recorder is in practical use in the cable world. The dots and dashes +sent into the wire on one side of the ocean according to the Morse +code, cause the siphon recorder through the means of electrified ink to +make a waving line on a tape. The signals are readily reducible again +if necessary to the dots and dashes of the Morse code because dots make +deflections to one side of the center of the tape and dashes to the +other. The operator who receives the message can therefore readily read +it. + + ALPHABET: + + A · -- + B -- · · · + C -- · -- · + D -- · · + E · + F · · -- · + G -- -- · + H · · · · + I · · + J · -- -- -- + K -- · -- + L · -- · · + M -- -- + N -- · + O -- -- -- + P · -- -- · + Q -- -- · -- + R · -- · + S · · · + T -- + U · · -- + V · · · -- + W · -- -- + X -- · · -- + Y -- · -- -- + Z -- -- · · + + FIGURES: + + 1 · -- -- -- -- + 2 · · -- -- -- + 3 · · · -- -- + 4 · · · · -- + 5 · · · · · + 6 -- · · · · + 7 -- -- · · · + 8 -- -- -- · · + 9 -- -- -- -- · + 0 -- -- -- -- -- + OR --] + +[Illustration: TO-DAY THERE ARE MANY CABLES ON THE BOTTOM + +MAP No. 1 + + WESTERN UNION + TRANS-ATLANTIC CABLES + AND CONNECTIONS] + + + + +THE STORY IN A RAILWAY LOCOMOTIVE + + +[Illustration: One of the Most Powerful Locomotives in the World] + +[Illustration: BOILER OF ARTICULATE COMPOUND LOCOMOTIVE. + +The wonder of our railroad systems to-day is the growth of the +locomotive. The necessity for economy in hauling long freight trains +has led to the development of this type of engine. Some idea of its +size can be had from the second picture, which shows the boiler and +firebox of the locomotive shown in the first picture. The firebox is so +large that an ordinary narrow-gauge locomotive of the old style can be +comfortably stored in it. + + LOADED WEIGHTS + + On driving wheels 475,000 lbs. + On truck wheels 30,000 lbs. + On trailing wheels 35,000 lbs. + Total of engine 540,000 lbs. + Total of tender 212,000 lbs. + + WHEEL BASE + + Driving, rigid 15 ft. 6 ins. + Total of engine 57 ft. 4 ins. + Total of engine and tender 91 ft. 5³⁄₁₆ ins. + + CYLINDERS + + Diameter H.P. 28 ins., L. P. 44 ins. + Stroke of piston 32 ins. + + WHEELS + + Diameter of driving wheels, outside 56 ins. + Diameter of truck wheels 30 ins. + Diameter of trailing wheels 30 ins. + Diameter of tender wheels 33 ins.] + +[Illustration: CYLINDERS BIG ENOUGH FOR MEN TO SIT DOWN IN + +LOW PRESSURE CYLINDERS OF ARTICULATED COMPOUND LOCOMOTIVE. + +In the picture we see the cylinders of the locomotive shown on the +previous page. Some idea of their size can be had from the fact that a +good-sized man can sit comfortably in each of them. + + BOILER + + Type Ex. Wagon Top + Working pres. per sq. in. 200 lbs. + Outside diam. at front end 100 ins. + Outside diam. at back end 112 ins. + Length firebox inside 173¹⁄₁₆ ins. + Length firebox, actual, inside 132 ins. + Width of firebox inside 108¹⁄₄ ins. + No. and diam. of tubes 334, 2¹⁄₄ ins. + No. and diam. of flues 48, 5¹⁄₂ ins. + Length of tubes 24 ft. 0 ins. + Combust. chamber length 39¹⁄₁₆ ins. + Grate area 99.2 sq. ft. + + HEATING SURFACE + + Tubes and flues 6462 sq. ft. + Water tubes 67 sq. ft. + Firebox 380 sq. ft. + Total 6909 sq. ft. + Superheating surface 1311 sq. ft. + + CLEARANCE LIMITATIONS + + Extreme height 16 ft. 5¹⁄₈ ins. + Extreme width 11 ft. 8¹⁄₂ ins. + Length over all 99 ft. 9⁵⁄₈ ins. + + MAXIMUM TRACTIVE POWER + + Working compound 115,000 lbs. + Working simple 138,000 lbs. + Factor of adhesion (working compound) 4.13 + Factor of adhesion (working simple) 3.44 + + TENDER CAPACITY + + Water 12,000 gals. + Fuel 16 tons] + +[Illustration: THE LOCOMOTIVE ENGINEER’S WORKROOM + +Here is a picture of one end of the boiler of this giant locomotive. +It would take a man more than seven feet high to bump his head in the +middle of it while standing on his feet.] + +[Illustration: This shows a picture of the engineer’s cab of one of +these great railroad machines. We are accustomed to see the levers +and other machinery for operating the engine right in the back of the +engine cab. Over or near the firebox. Upon looking closely we find +that the operating machinery is at the side of the locomotive and +far forward in the cab. In fact there is a complete set of operating +machinery on both sides of the cab, so that the engineer can run the +engine from whatever side he happens to be on. This is very necessary, +particularly in switching. Near the end of the cab where the engineer +used to sit you will notice a peculiar pipe-like arrangement. This +is not for operating the engine, but is the automatic stoker, which +is fully explained in the next picture. An engine of this size will +require seven tons of coal per hour.] + +[Illustration: A MACHINE WHICH DOES THE WORK OF FOUR FIREMEN + +When these large locomotives were first used it was found that no one +fireman could shovel in enough coal to keep the steam up. It would +require three or four firemen working constantly to shovel enough coal +to keep this engine going. Man’s inventive genius came to the front, +however, and now we have an automatic fireman, so to speak. Instead of +shoveling coal on one of these engines the fireman merely operates a +lever. This is a picture of the Sweet locomotive stoker installed in +a railroad engine. This machine automatically conveys coal from the +tender to the locomotive, raises it by an elevator to a point above the +fire door, dumps it into the firebox and spreads it evenly over the +grate.] + +[Illustration: This is the new type of electric locomotive being used +by the New York Central system] + +[Illustration: HOW A FAST TRAIN TAKES WATER WITHOUT STOPPING + +The fast express trains haven’t time to stop and take water from the +tank at the side of the railroad as in former days. This picture shows +a tank built between the tracks which enables the engineer to fill +his boilers without slackening speed. When approaching this tank the +engineer simply lowers a tube into the water, the end of which is a +scoop. The moving engine thus forces the water up into the tube, from +which it runs into the boiler.] + +[Illustration: This is an improved signal tower from which switches are +operated. If you were ever in a signal tower you will not recognize +this as one, for you are used to seeing a room full of levers which the +tower man had to pull hard when he wished to throw a switch. By the old +way the end of the lever was attached to a wire which was connected +with the switch. The wire running through pipes, when the operator +pulled the lever the switch was pulled shut by the pull on the wire. In +this new plan the switch is controlled by electricity, and the operator +has merely to pull out a plug as shown in the picture, which is much +easier than operating a lever.] + +[Illustration: WHAT MAKES A WIRELESS MESSAGE GO + +Sketch showing arrangement of aerial on ship equipped with the Marconi +Direction Finder, an instrument which tells the sea captain the exact +points of the compass from which wireless distress signals are being +sent and enables ships to avoid collisions in fog.] + + + + +The Story in the Wireless + + +What is the Principle of the Wireless Telegraphy? + +Drop a stone in a pool of water. Circular waves or ripples will travel +outward in all directions. That is the principle of wireless telegraph. + +If a chip be floating on the water it will be rocked by each ripple, +just as a wireless receiving station will respond to the electrical +waves or impulses that make up a wireless message. It is not known +just how the invisible wireless waves are propelled through space, +but they travel through the ether in the air in very much the same +way as do sound waves. The electrical signals, too, are received only +by apparatus that is attuned to them; that is, they can not be heard +except at wireless stations, any more than sound can be heard by the +ears of a deaf person. + +The wireless waves have a definite length, can be measured in feet or +meters, and are regulated according to the distance the message is to +travel. Stations that send a few hundred miles use a wave length of six +hundred meters, or less, while at the powerful land stations used for +trans-atlantic work the wave lengths used run into as many thousands. + + +Why Don’t the Messages Go to the Wrong Stations? + +So that the hundreds of messages hurtling through space at the same +time will not interfere, the wireless stations are equipped with +tuning-apparatus through which they can adjust their wave length to +receive the particular message desired. A different wave length is +used by each ship or wireless shore station, and even though dozens of +messages fill the air, the minute the wireless operator adjusts his +tuner to the length of the station he is after, that particular message +stands out very strongly and all the others grow dim. + +[Illustration: The Marconi Wireless station at Miami, Fla., which is +typical of the shore stations that handle messages to several thousand +ships at sea.] + + +How Does the Wireless Reach Ships at Sea? + +All ships at sea report their positions regularly; thus it is a simple +matter for a shore station to send a wireless message to the ship to +which it is addressed. For example, the Marconi station at Sea Gate, +New York, wants to reach the Lusitania. The operator looks up that +vessel on the list and notes her call signal and wave length. He +adjusts his tuner to correspond and calls her signal, M F A, repeating +it three times. + +The wireless man on the vessel, knowing that he is within range of a +shore station, has set his tuner at the wave length assigned to him and +is listening. When his call letters are heard, he acknowledges them +and signals to go ahead with the message. When it has been given, the +Sea Gate station “signs off” with its call letters W S E and the ship +operator enters in his record that that particular message reached him +via the Marconi station at Sea Gate. Thus, with the wide variety in +wave lengths, no confusion of messages exists and any desired ship or +shore station can be called, just as a direct telephone connection is +secured by giving the central station the call number of the subscriber +wanted. + + +What Kind of Signs Are Used in the Wireless? + +The actual wireless message is composed of dots and dashes, which, in +certain combinations, stand for certain letters of the alphabet. This +is done through opening and closing the electrical circuit by pressing +a key, a sharp touch forming a dot and a longer pressure a dash, as +with the wire telegraph. + +If secrecy in a wireless message is wanted, the words are sent in +cipher which, of course, cannot be understood by outsiders. The +Government sends thousands of words each day without a single word +meaning anything to the wireless stations that happen to be “listening +in.” While it is true that any one owning a wireless receiving set may +listen to messages flying through the air, every person within hearing +who understands the Morse Code can read the telegrams that come into a +telegraph office. Knowledge thus gained, however, is of little value, +as the law provided heavy penalties for disclosing the contents of any +kind of telegraph message. + + +What Does a Wireless Equipment Consist of? + +The various apparatus that comprises a wireless equipment can not be +properly explained without the use of technical language, but the +general principle of operation is somewhat as follows: If a small loop +of copper wire, with a slight separation between the ends, is placed +across a room from an electric spark, it will be slightly affected. +Increase the electrical current to far greater power and control it, +and the invisible electrical wave may be thrown many miles. To send +a message across the ocean, the current used by the modern wireless +station is so powerful that it will pass through storm and fog, +even through mountains, without losing much of its force. When this +tremendous force is released by pressing the telegraph key, it leaps +from the aerial wires, or antennae, travels across the Atlantic and is +picked up by a corresponding aerial, attuned to receive the signal. + +[Illustration: Pack and riding horses grouped together ready for +unloading the Marconi wireless set used in the cavalry. + +Station set up and working. + +WORKING THE WIRELESS IN THE ARMY.] + +The aerial, or antennae, as it is called in a wireless work, is made up +of copper wires. On a ship these are strung between the masts, usually +consisting of two, four or six wires held apart by crosspieces. Two or +more wires lead down from this to the wireless cabin. + +The coil or transformer is the apparatus which produces the spark that +forms the electrical waves. In small stations, the length and thickness +of the spark and the speed of vibration is regulated by a thumb screw. +Transformers are used when the power is taken from the alternating +current of an electric light circuit. + +The gap, which the electrical current jumps when the telegraph key is +pressed down, is composed of two rods which slide together or apart to +vary the length of the spark. + +The simplest type of sending station consists of the antenna, battery, +coil, wireless key and spark gap. If a change in wave length is desired +a transmitting tuning coil must be added. + +The receiving apparatus contains a detector, which is chiefly two +mineral points lightly touching and connected with a sensitive head +telephone. The incoming signals are heard as long and short buzzing +sounds corresponding to the dots and dashes. The receiving tuning coil, +used to adjust wave lengths, is operated by simply moving sliding +contacts along a bar until the signals are more plainly heard. While +the large stations have more complicated apparatus, the principle +remains the same. + +[Illustration: The masts for the cavalry wireless sets are so attached +that they can be loaded and unloaded with the utmost rapidity; a +complete station can be erected or dismantled in less than ten minutes.] + +[Illustration: The gasoline engine which supplies the power for +operating a cavalry wireless station is fitted to the saddle frame and +is light enough to be carried by one horse. + +THE WIRELESS IN THE ARMY] + + +How High Do Wireless Masts Have to be? + +The towering masts of the Marconi Trans-Oceanic stations are often +supposed to rise to their great height, so that an antennae will be +raised above the obstructions between. If this were necessary, two +wireless stations separated by the Atlantic would have to have masts +one hundred and twenty-five miles high to rise above the curvature +of the earth. The path of the wireless waves, however, is not in a +straight line, but follows the curvature of the earth. Scientists +explain this by saying the rarefied air above the earth’s surface acts +as a shell enclosing the globe. + +The speed of wireless messages is placed at 186,000 miles per second. A +wireless message will thus cross the Atlantic in about one-nineteenth +of a second--a period of time too small for the human mind to grasp. +In other words, the wireless flash crosses in a fraction of a second a +distance that the earth requires five hours to turn on its axis and the +fastest ships take nearly a week to cross. + +The longest distance over which a wireless message can be sent is not +definitely known; the present record was made in September, 1910, by +Marconi from Clifden, Ireland, to Buenos Aires, Argentina, a distance +of 6700 miles. + +[Illustration: THE WIRELESS PREVENTS ACCIDENTS AND SAVES MANY LIVES + +This photograph makes us appreciate what a wonderful aid is wireless to +navigators. On Easter Sunday, 1914, the U. S. Revenue Cutter “Seneca,” +patrolling the North Atlantic, found these two gigantic icebergs in +the regular steamer lanes and sent out wireless warnings to all nearby +steamships.] + +[Illustration: HOW THE WIRELESS IS INSTALLED ON FAST TRAINS + +RAILROAD WIRELESS.--ANTENNA ON CARS.] + +[Illustration: WIRELESS STATION ON TRAINS.] + +[Illustration: WIRELESS STATION IN U. S. ARMY + +City side of Scranton station, Lackawanna R.R., showing aerial of +wireless which communicates with trains.] + +[Illustration: + + Photo by Stefano + +WIRELESS RECEIVING STATION IN U. S. ARMY.] + +[Illustration: Guglielmo Marconi, Inventor of wireless telegraphy.] + + +The Man Who Invented Wireless Telegraphy. + +Communication without wires for thousands of miles across oceans, from +continent to continent, is a far cry from sending a wireless impulse +the length of a kitchen table. That is the development of twenty years. + +To properly trace the development of wireless telegraphy, however, it +is necessary to go back eighty-three years to when, in 1831, Michael +Faraday discovered electro-magnetic induction between two entirely +separate circuits. Steinheil, of Munich, too, in 1838, suggested +that the metallic portion of a grounded electrical circuit might be +dispensed with and a system of wireless telegraphy established. Then, +in 1859, Bowman Lindsay demonstrated to the British Association his +method of transmitting messages by means of magnetism through and +across the water without submerged wires. In 1867 James Clerk Maxwell +laid down the theory of electro-magnetism and predicted the existence +of the electric waves that are now used in wireless telegraphy. +Dolbear, of Tufts College, in 1836, patented a plan for establishing +wireless communication by means of two insulated elevated plates, but +there is no evidence that the method proposed by him effected the +transmission of signals between stations separated by any distance. +A year later Heinrich Rudolph Hertz discovered the progressive +propagation of electro-magnetic action through space and accomplished +the most valuable work in this period of speculation and experiment. + +Just twenty years ago, at his father’s country home in Bologna, +Guglielmo Marconi, then a lad just out of his ’teens, read of the +experiments of Hertz and conceived the first wireless telegraph +apparatus. This was completed some months later and a message in the +Morse Code was transmitted a distance of three or four feet, the length +of the table on which the apparatus rested. + +Satisfied that he had laid the foundation of an epoch-making discovery +young Marconi pursued his experiments and filed the first patent on the +subject on June 2, 1896. Further experiments were carried on in London +during that year and at the request of Sir William H. Preece, of the +British Post Office, official tests were made, first over a distance of +about 100 yards and later for one and three-quarter miles. + +During the year following Mr. Marconi gave several demonstrations to +the officials of the various European governments and communication +was established up to 34 miles. In July of this year, 1897, the first +commercial wireless telegraph company was incorporated in England and +the first Marconi station was erected at the Needles, Isle of Wight. + +On June 3, 1898, Lord Kelvin visited this station and sent the first +paid Marconigram. A month later the events of the Kingstown Regatta in +Dublin were reported by wireless telegraphy for a local newspaper from +the steamer “Flying Huntress.” In August of that year the royal yacht +“Osborn” was equipped with a wireless set, in order that Queen Victoria +might communicate with the Prince of Wales, who was at Ladywood Cottage +and suffering from the results of an accident to his knee. For sixteen +days, constant and uninterrupted communication was maintained. Then on +Christmas Eve was inaugurated the first lightship wireless service, +messages being sent from the East Goodwin lightship to the lighthouse +at South Foreland. + +[Illustration: PREPARING TO SEND MESSAGES ACROSS THE OCEAN + +This photograph shows how wireless messages are prepared for direct +transmission across the ocean. The dots and dashes of the telegraphic +code are punched on tapes by skilled operators, thus insuring accuracy +and a permanent record of each message. Five or six operators, and +sometimes more, are steadily preparing these tapes, which are pasted +together and run through a machine which operates the key at each +perforation. A speed of 100 words a minute is thus obtained.] + +Three months later the first marine rescue was effected through this +installation. The steamship “R. F. Matthews” ran into the lightship +and lifeboats from the South Foreland station promptly responded to +the wireless appeal for aid. The most important wireless event abroad +during the year 1899 was the establishing of communication across the +English Channel, a distance of thirty miles. + +The American public next learned something of Marconi’s invention, for +in September and October of that year wireless telegraphy was employed +in reporting the International yacht races between the “Shamrock” and +the “Columbia” for a New York newspaper. At the conclusions of the +races, the naval authorities requested a series of trials, during which +wireless messages were exchanged between the cruiser “New York” and +the battleship “Massachusetts” up to a distance of about 36 miles. On +leaving America, Marconi fitted the liner “St. Paul” with his apparatus +and when 36 miles from the Needles Station, secured wireless reports +of the war in South Africa. These were printed aboard the vessel in a +leaflet called “The Transatlantic Times,” the first of the chain of +wireless newspapers now published daily on practically all passenger +steamships. Six field wireless sets were dispatched to South Africa +about this time and were later of considerable service in the Boer War. + +[Illustration: In the foreground of this picture is seen the automatic +transmitter with the message perforated tape running through. This is +one of the smaller wireless equipments; much larger ones are used at +the new Marconi stations.] + +The year 1900 brought the first commercial wireless contracts. By +agreement with the Norddeutscher Lloyd, Marconi apparatus was installed +on a lightship, a lighthouse and aboard the liner “Kaiser Wilhelm der +Grosse.” On July 4th the British Admiralty entered into a contract +for the installation of Marconi apparatus on thirty-two warships and +shore stations and the erection of the high power station at Poldhu was +commenced. + +~WORLD WIDE USE OF THE WIRELESS~ + +Work on similar station at Cape Cod was begun early in 1901 and on +August 12th the famous Nantucket Island and Nantucket lightship +stations opened to report incoming vessels by wireless. Heavy gales +in September and November wrecked the masts at both Poldhu and +Cape Cod stations and these were replaced by four wooden towers, +210 feet high. Important experimental work was then shifted to St. +John’s, Newfoundland, and on December 12th and 13th, signals were +received across the Atlantic from Poldhu. This to Marconi was a great +achievement and the forerunner of the present day trans-atlantic +service. But with the announcement that the long dreamt of feat had +been accomplished a flood of vituperation from scientific men was let +loose. It was nonsense; it was deliberate deception; the reading was +in error, were among the comments. Another prank of the “young man +with a box,” one scientist termed it. It is amusing now to recall this +extraordinary treatment, but it was hardly so amusing to the young +inventor, then in his twenty-seventh year. + +But in spite of the skepticism, developments followed rapidly from then +on and in 1902, the year in which the American Marconi Company was +established, full recognition to wireless telegraphy was given by the +various governments. + +The wonderful growth of the Marconi system within the last twelve years +is well known to all and does not require detailing. But in view of its +youth as an industry and its inauspicious beginning, a glimpse into +what the present day Marconi system comprises may be interesting. + +More than 1800 ships are equipped with Marconi wireless and its shore +stations are landmarks in practically every country on the globe. + +Press and commercial messages are transmitted daily from continent to +continent direct. + +Shore to ship and ship to shore business each year runs into millions +of words. + +Marconi wireless within seventeen years, has become an absolute +necessity in the maritime field, an invaluable aid in others. Regular +communication has been established with icebound settlements and desert +communities, and official running orders transmitted to moving railway +trains. Its service is dependable under all conditions and embraces +activities and locations inaccessible to any other telegraph system. +Continuous service is maintained and wireless messages for all parts of +the world at greatly reduced rates are received at any Western Union +Office. + +The direction finder and wireless compass are recent Marconi inventions. + +A wide variety of types of Marconi equipment are designed for the +merchant marine, warships, submarines, pleasure craft, motor cars +and railroad trains; also portable signal corps sets, apparatus for +aircraft, cavalry sets, knapsack sets and high-power installations for +trans-ocean communication. + + + + +How Does a Fly Walk Upside Down? + + +There is a little sucker on the end of each of the fly’s feet which +makes his foot stick to the ceiling or any other place he walks, and +which he can control at will. It is made very much like the sucker +you have seen with which a boy can pick up a flat stone--a circular +piece of rubber or leather with a string in the middle and more or +less bell shaped underneath. A boy can pick up a flat stone with this +kind of a sucker by pressing the rubber or leather part down flat on +the stone and then pulling gently on it by the string. When he does +this he simply expels the air which is between the leather part of +the sucker and the stone, which creates a vacuum and the pressure of +the air on the outside part of the leather enables him to pick it up. +The fly has little suckers like these on each of his feet, and they +act automatically when he puts his foot down. Of course the sticking +power of each foot is adjusted to the weight of the fly, just as the +sticking or lifting power of the boy’s sucker is regulated by the +weight of the stone or other object he tries to pick up. If the weight +of the object is sufficient to overcome the sticking power which the +vacuum creates, the stone cannot be lifted. + + + + +What Is Money? + + +It is quite difficult to give a broad definition of money that will be +understood by all, for in different ages and lands many things have +been used as money besides the coins and bills which we think of only +when we think at all what money is. Anything that passes freely from +hand to hand in a community in the payment of debts and for goods +purchased, accepted freely by the person who offers it without any +reference to the person who offers it, and which can be in turn used +by the person accepting it to give to some one else in payment of debt +or for the purchase of goods, is money. This is rather a long sentence +and perhaps difficult to understand, and so we will try to analyze +what this means. If some one offered you a pretty stone as money in +payment of a debt, it would be as good as any kind of money if you in +turn could pass it on to any other person to whom you owed a debt or in +payment of something you bought. The stone might appear to you to be +valuable but it would not be good money unless you could count on every +one else in the community accepting it at the same value. If everybody +accepts it at the same value, it is as good as any kind of money. So +that anything which is acceptable to the people in any community as a +unit of value to pay debts, is good money, provided everybody thinks so +and accepts it that way. In this case, then any kind of substance might +become money provided it was used and accepted by everyone. + + + + +Why Do We Need Money? + + +We need money for the sake of the convenience which it provides in +making the exchange of one kind of wealth for another and as a standard +of value. When a community has adopted something or anything which +is regarded by all of the people as a standard of value, all of the +difficulties of trading disappear. + + + + +Who Originated Money? + + +The earliest tribes of savages did not need money because no individual +in the tribe owned anything personally. All the property of the tribe +belonged to the tribe as a whole and not to any particular person. +Later on, when different groups of savages came into contact with each +other, there arose the custom of bartering or exchanging things which +one tribe possessed and which the other tribe wanted. In that way arose +the business of trading or of what we call doing business, and soon the +need of something by which to measure the values of different things +arose. Some of the old Australian tribes had a tough green stone which +was valuable for making hatchets. Members of another tribe would see +some of this stone and notice what good hatchets could be made from +it--better hatchets than they had been able to make. Naturally they +wanted it so much that it became very valuable in their eyes and so +they came wanting to buy green stones. But they had nothing like what +we could call money today. They had, however, a good deal of red ochre +in their lands which they used to paint their bodies. They got this +red ochre out of the ground on their own lands just as the other tribe +got green stones out of its ground, and those who owned the green +stones which were good for making hatchets, wanted some red ochre very +much, and so they traded green stones for red ochre. The green stones +then took on a value in themselves for making exchanges for various +commodities, and before long became a kind of money inside and outside +the community so that when they wanted to obtain anything, the price +was put by the merchant as so many green stones and he accepted these +in payment for goods given in exchange. He was willing to do this +because he knew he could use them in making trades for almost anything +he might want, provided he had enough of the green stones. So you see +these green stones of the Australian tribe became a rudimentary kind of +money, just because a desire had arisen to possess them; and the red +ochre was actual money in the same sense, for when this tribe found +that other tribes would value this red ochre, they began getting the +things they wanted and paying for them in red ochre. But the “unit of +value” had to be developed to make a currency that was elastic. It +required something that could be carried about easily--in fact it had +to be something small enough so a number of units of value could be +carried about without too much trouble. The Indians of British Columbia +solved this difficulty of making an elastic currency by adopting as a +unit of value a haiqua shell which they wore in strings as ornamental +borders of their dresses--and one string of these shells was worth +one beaver’s skin. These shells then were real money and one of the +earliest forms of it. + +The skins of animals were long used by savage tribes as money. The +skins were valuable in trading and a man’s fortune was reckoned by the +number of skins he owned. As soon as the animals became domesticated, +however, the whole animal replaced the skin as the unit of value. This +change undoubtedly came because a whole animal is more valuable than +only its skin. The first skins obtainable however were worn by wild +animals--the kind that the people could not deliver to someone else +alive and whole. But when the animals became domesticated, which meant +that man tamed them and kept them where he could control them at will, +the skin and the wild animal ceased to be a unit of value because it +was an uncertain kind of money. Among domestic animals, oxen and sheep +were the earliest forms of money--an ox was considered worth ten sheep. +This idea of using cattle as money was used by many tribes in many +lands. We find traces of it in the laws of Iceland. The Latin word +pecunia (pecus) shows that the earliest Roman money was composed of +cattle. The English word fee indicates this also. The Irish law records +show the same evidence of the use of cattle as money and within recent +years the cattle still form the basis of the currency of the Zulus and +Kaffirs. + +When slavery became prominent many lands adopted the slaves as the unit +of value. A man’s wealth was reckoned by the number of slaves he owned. + +Then, when the practice of agriculture became more common, people +used the products of the soil as money--maize, olive oil, cocoanuts, +tea and corn--the latter is said to pass current as actual money in +certain parts of Norway now. They used these products of the soil for +money even in our own country. Our ancestors in Maryland and Virginia +before the Revolutionary War, and even after, used tobacco as money. +They passed laws making tobacco money and paid the salaries of the +government officials and collected all taxes in tobacco. + +Other early forms of money were ornaments and these serve the purpose +of money among all uncivilized tribes. In India they used cowrie +shells--a small yellowish-white shell with a fine gloss. The Fiji +Islanders used whales’ teeth; some of the South Sea Island tribes used +red feathers; other nations used mineral products as money--such as +salt in Abyssinia and Mexico. + +Up to this point we have talked about the things used as money from +the standpoint of primitive forms of money. Today the metals have +practically driven all these other crude forms of money out. + + + + +Metallic Forms of Money. + + +~WHY WE USE METALS FOR COINING~ + +The use of metals as money goes far back in the history of civilization +but it has never been possible to trace the historical order of the +adoption of the various metals for the purposes. Iron according to the +statement of Aristotle was at one time extensively used as money. +Copper, in conjunction with iron, was used in early times as money in +China; and until comparatively a short time ago was used for the coins +of smaller value in Japan. Iron spikes were used in Central Africa +and nails in Scotland; lead money is now used in Burmah. Copper has +long been used as money. The early coins of England were made of tin. +Finally, however, came silver and silver was the principal form of +money up to a few years ago. It was the basis of Greek coins introduced +at Rome in 269 B. C. Most of the money of Medieval times was composed +of silver. + +The earliest traces of gold used as money is seen in pictures of +ancient Egyptians “weighing in scales heaps of gold and silver rings.” + + + + +Why Do We Use Gold and Silver as Money Principally? + + +There are a good many reasons why gold and silver have become almost +universal materials for use as money. Perhaps this will be better +understood if these reasons are set down in order. + +1st. It is necessary that the material out of which money is made +should be valuable, but nothing was ever used as money that had not +first become desirable and, therefore, valuable as money. This is only +one of the incidental reasons for taking gold and silver for coining +money. + +2nd. To serve its purpose best, money should be easy to carry +around--in other words, its value should be high in proportion to its +weight. + +The absence of this quality made the early forms of money such as +skins, corn, tobacco, etc., undesirable. It was difficult to carry very +much money about. Imagine the skin of a sheep worth a dollar, say, +and having to carry ten of them down to pay the grocer. To a certain +extent this difficulty occurred with iron and copper money and in times +when they used live cattle it was a pretty expensive job to pay your +debts because, while the cattle could move, it was still expensive to +drive them from place to place. A man who accepted a thousand cattle +in payment had to go to some expense in getting them home. Then it was +expensive to have money when live cattle were used because the cattle, +of course, had to be fed and from that point of view the poor man who +had no money was better off than the rich man who had money. When +cattle were used as money it cost a lot to keep it. Our kind of money +doesn’t eat anything; in fact, if you put it in a savings bank, it will +earn interest money for you. But when cattle were used as money it cost +a great deal to keep them and so it was worse than not earning any +interest. + +3rd. Another quality that money should possess is divisibility without +damage and also the quality of being united again. This quality is +possessed by the metals in every sense because they can be fused, while +skins and precious stones suffer in value greatly when they are divided. + +4th. The material out of which money is made should be the same +throughout in quality and weight so that one unit of money should be +worth as much as any other unit. This could never be true of skins or +cattle as the difference in the size of skins is very great sometimes, +and a small skin from the same animal could not be worth as much as a +large one, or a skin of an animal of inferior quality so valuable as a +very fine one. + +5th. Another quality which money should possess is durability. This +requirement made it necessary to use something else besides animals or +vegetable substances. Animals die and vegetables will not keep and so +lose their value. Even iron is apt to rust and through that process +lose more or less of its value. + +6th. The materials out of which money is made should be easy to +distinguish and their value easy to determine. For this reason such +things as precious stones are not good to use as money because it +takes an expert to determine their value and even they are not always +certain to be correct. + +7th. Then a very important quality that the material out of which money +is made is that its value should be steady. The value of cattle varies +very greatly and, in fact, most of the materials out of which the first +currencies were made were subject to quick change in value in a short +time. The value of gold and silver does not change excepting at long +intervals. Gold and silver are both durable and easily recognizable. +They can be melted, divided and united. The same is true of other +metallic substances, but iron as stated is subject to rust and its +value is low; lead is too soft. Tin will break, and both of them and +copper also are of low value. Gold and silver change only slowly in +value when the change at all; they do not lose any of their value by +age, rust or other cause; they are hard metals and do not, therefore, +wear. Their value in proportion to the bulk of the pieces used for +money is so large that the money made from them can be carried without +discomfort and it is almost impossible to imitate them. + + + + +Who Made the First Cent? + + +Vermont was the first state to issue copper cents. In June, 1785, she +granted the authority to Ruben Harmon, Jr., to make money for the state +for two years. In October of the same year, Connecticut granted the +right to coin 10,000 pounds in copper cents, known as the Connecticut +cent of 1785. Massachusetts, in 1786, established a mint and coined +$60,000 in cents and half cents. In the same year, New Jersey granted +the right to coin $10,000 at 15 coppers to the shilling. In 1781 the +Continental Congress directed Robert Morris to investigate the matter +of governmental coinage. He proposed a standard based on the Spanish +dollar, consisting of 100 units, each unit to be called a cent. His +plan was rejected. In 1784, Jefferson proposed to Congress, that the +smallest coin should be of copper, and that 200 of them should pass for +one dollar. The plan was adopted, but in 1786, 100 was substituted. In +1792 the coinage of copper cents, containing 264 grains, and half cents +in proportion, was authorized; their weight was subsequently reduced. +In 1853 the nickel cent was substituted and the half cent discontinued, +and in 1864 the bronze cent was introduced, weighing 48 grains and +consisting of 95 per cent. of copper, and the remainder of tin and zinc. + + + + +How Did the Name Uncle Sam Originate? + + +The name Uncle Sam is a jocular name long in use for the Government of +the United States. + +Shortly after the war of 1812 was declared, Elbert Anderson of New +York State, who was a contractor for the army, went to Troy, New York, +to purchase a quantity of provisions. At that place the provisions +were inspected, the official inspectors being two brothers named +Wilson--Ebenezer and Samuel. The latter was very popular among the men +and was known as “Uncle Sam Wilson” and everybody called him that. +The boxes in which the provisions were packed were stamped with four +letters, E. A. for Elbert Anderson, and U. S. for United States. One of +the men engaged in making the inspection asked another of the workmen +who happened to be a jocular fellow, what the letters E. A. U. S. on +the boxes stood for. He said in reply that he did not know but thought +they probably meant Elbert Anderson and Uncle Sam Wilson, and that they +had left off the W which would stand for Wilson. The suggestion caught +on quickly and as such things often do, the joke spread rapidly so that +everybody soon thought of the name “Uncle Sam” whenever they saw the +letters U. S. on anything or in any place. + +The suit of striped trousers and long tailed coat and beaver hat +in which Uncle Sam is now always represented in pictures, was the +inspiration of the famous cartoonist. + +[Illustration: THE WORLD’S BREAD LOAVES + + Egypt + 2500 B.C. + + Unleavened Bread + 2000 B.C. + + Pompeii + 50 A.D. + + Palestine + + Modern American Loaf + + England + + England + + France + + Hungary + + Spain + + Switzerland + + Bohemia + + Holland + + Italy + + Austria + + Germany + + Balkan States] + +[Illustration: HARVESTING WHEAT.] + + + + +The Story in a Loaf of Bread + + +Why is Bread so Important? + +The history of bread as a food reads like a romance. It has played an +important part in the destinies of mankind and its struggles through +the ages to perfection. The progress of nations through their different +periods of development can be traced by the quality and quantity of +bread they have used. + +No other food has taken such an important part in the civilization of +man. + +To a large extent it has been the means of changing his habits from +those of a savage to those of a civilized being. It has supplied the +peaceful pursuits of agriculture and turned him from war and the chase. + +It is an interesting fact that the civilized and the semi-civilized +people of the earth can be divided into two classes, based upon their +principal cereal foods: the rice eaters and the bread eaters. + +Every one admits that rice eaters are less progressive, while bread +eaters have always been the leaders of civilization. + +It is an interesting fact that just as Japan is changing from a +rice-eating nation to a bread-eating nation she is asserting her power. + +Any one who stops to consider the history of nations will see that this +matter of what we eat is the one question of vital importance. + +Bread is one of the earliest, the most generally used and one of the +most important foods used by man. Without bread the world would not +exist without great hardship. On bread alone a nation of people can +exist, and to sit down to a meal without it causes us to feel at once +that something is missing. + + +What Was the Origin and Meaning of Bread? + +Bread is baked from many substances, although when we think of bread, +we usually think of wheat bread. It is sometimes made from roots, +fruits and the bark of trees, but generally only from grains such as +wheat, rye, corn, etc. The word bread comes from an old word _bray_, +meaning to pound. This came from the method used in preparing the food. +Food which was pounded was said to be brayed and later this spelling +was changed to bread. Properly speaking, however, these brayed or +ground materials are not really bread in our sense of using the term +until they are moistened with water, when it becomes dough. The word +_dough_ is an old one meaning to “moisten.” This dough was in olden +times immediately baked in hot ashes and a hard indigestible lump of +bread was the result. Accidentally it was discovered that if the dough +was left for a time before baking, allowing it to ferment, it would +when mixed with more dough, swell up and become porous. Thus we got our +word loaf from an old word _lifian_, which meant to raise up or to lift +up. + + +When Was Wheat First Used in Making Bread? + +It is not clearly known when or by whom wheat was discovered, but it +seems to have been known from the earliest times. It is mentioned in +the Bible, can be traced to ancient Egypt and there are records showing +that the Chinese cultivated wheat as early as 2700 B.C. To-day it +supplies the principal article for making bread to all the civilized +nations of the world. + +The origin of the wheat plant is said to have been a kind of grass +which is given a Latin name _Ægilops ovata_ by the botanists. + + +Will Wheat Grow Wild? + +This is a question that has puzzled the world’s scientists for more +than two thousand years. From time to time it has been reported by +investigators in various parts of the world that here and there wheat +has been found growing wild and doing well, but every time a further +investigation is made, it develops that the wheat has been cultivated +by some one. There is as yet no evidence for believing that wheat will +grow in a wild state. + + +What is the Difference between Graham Flour and Whole Wheat? + +Graham flour from which Graham bread is baked is made from unbolted +flour. The process of bolting flour, which is described in one of the +following pages, consists briefly in taking out of it all but the +inside of the grain of wheat. When this has been done, we have pure +white flour. + +In making Graham flour every part of the grain of wheat is left in the +flour, and ground up finely. Many people think that Graham flour is +made from a special grain called Graham, but this is not true. It is +said that Graham bread is not so good for you because it contains the +outside covering of the wheat grain or bran which is composed of almost +pure silica, the same substance of which glass is made, and cannot +therefore be good for us. + +Whole wheat flour is made from the whole grain of wheat from which the +outside covering or bran has been separated. It contains everything but +the bran and is therefore the most nutritious flour made. + +The grain of wheat has several coverings of bran coats, the outer one +of which is the one composed of silica, and which is not valuable +as food. Underneath this husk--are found the inner bran coats, +which contain the gluten. Gluten is a dark substance containing the +flesh-forming or nitrogenous elements, which are valuable in muscle +building. The inside or heart of the grain of wheat consists of cells +filled with starch, a fine white mealy powder which has little value +as food, but is a great heat producer. Sometimes in making whole wheat +flour, the heart of the grain is also removed, making a pure gluten +flour. The name whole wheat for flour is not accurate, therefore, for +Graham flour is made of the whole wheat grain, while “whole wheat” +flour is made of only certain parts of the grain of wheat. + +[Illustration: Wheat conditioners for tempering the wheat before being +ground by the corrugated roller mills.] + + +How is Flour Made? + +In great factories the raw material is frequently taken in at one end +and comes out of the opposite end as a finished locomotive, a Pullman +palace car, or a pair of shoes. There is no such progression in making +flour. The wheat comes in at one place as a plain Spring or Winter +wheat and at another goes out as flour, but in the process parts of +it may go from top to bottom of the big mill 30 times. Instead of a +factory where everything moves along from hand to hand or machine to +machine, the flour mill is like a human body--a huge framework like the +bones, with thousands of carrying devices, “elevators,” “spouts” and +“conveyors,” like the veins and arteries of the blood-carrying system. +Stop up a vein of wheat, the mill becomes clogged, and finally must +shut down if it cannot be mechanically relieved. It is an intricate and +intensely interesting process, the result of year-to-year experience. + +[Illustration: SEPARATING THE WHEAT FIBER AND GERMS + +Purifier for separating the fiber, germ, and other impurities from the +semolina (grits) before it is finally crushed or ground into flour by +smooth roller mills.] + + +Scouring that Suggests a Dutch Kitchen. + +From the storage bins the wheat is drawn off through conveyors to the +first of several cleaning processes, the “separators,” where the coarse +grain which naturally comes with the wheat, such as corn and oats, and +imperfect kernels of wheat, is taken out. After this general cleaning +the grain goes to the “scouring machine,” which is an interesting +device--a rapidly revolving cylinder with what are called “beaters” +attached. The grain is thrown against perforated iron screens. Any +clinging dirt is loosened, and a strong current of air passing through +the cylinder is constantly “calling for dust,” as the miller aptly +expresses it, and carries the impurities away as dust and dirt. Indeed, +the cleaning process seems to be a constant one from the time the +wheat enters the mill until the flour is made. Having been cleansed, +the wheat is now ready for the rolls except for a “tempering” process, +which is to prepare the grain, so that the outside of the wheat may be +taken off without injury to the inside or kernel. + +Then as the grain passes to the rolls there begins a gradual reduction +of wheat to flour which is most intricate. + +The first sets of rolls are corrugated and so adjusted as to “break” +each grain of wheat into 12 to 15 parts. The “breaking” process goes on +through five different sets of rolls. + +[Illustration: GRINDING THE WHEAT FOR MAKING FLOUR + +Corrugated roller mills for grinding the wheat after it has been +cleaned.] + +[Illustration: Wooden spouts for conveying the different products, bran +and partly ground wheat, from one machine to another.] + +[Illustration: THE FLOUR IS READY FOR BAKING + +Gyrating sifter for separating the bran particles from the flour and +semolina.] + + +The Big Bolters with Silken Sieves. + +Closely allied with the rolling process is the bolting process, +which, working hand in hand with it has made modern flour making so +perfect. The bolting process consists of a series of sieves--a sifting +of the broken grain so that it is finally, after repeated breaking +and sifting, a flour. The bolter machine contains a number of sieves +covered with silk bolting cloth with varying mesh or number of threads +to the square inch. This bolting machine, moving rapidly, makes from +8 to 10 different separations of the material. From rolls to bolters, +from bolters to purifiers, from purifiers to rolls, over and over, the +process continues, until five different grades of “middlings” have +been selected by the mechanical hands of the millers. The purifier is +still another step to the process. It is a machine having eight sieves +of different mesh. The “middlings” flow down over the different sieves +in a thin sheet, a current of air meantime drawing all impurities out. +With this purifying process completed, the material is ready for the +smooth rolls. + + +The Mill Tries to Catch Up with the Bins. + +When the flour is made it is conveyed to large round bins--five sheets +of hard wood pressed together. These bins are being filled all the time +and being emptied all the time, the mill being about seven hours behind +the capacity of the bins, so that from start to finish the modern flour +mill is a tremendously busy place. + +Underneath the bins and connecting with them are the flour +packers--automatic devices which pack a 3¹⁄₂-pound paper sack as +accurately as a 196-pound barrel. The filled packages are sent down +“chutes” to the shipping floor. There they go to wagons or through +other chutes to boats. + + + + +The Story in a Lead Pencil[5] + + [5] Courtesy of The Scientific American. + + +Why Do They Call Them Lead-pencils? + +~WHERE LEAD PENCILS COME FROM~ + +The lead-pencil so generally used today is not, as its name would +imply, made from lead, but from graphite. It derives its name from +the fact that prior to the time when pencils were made from graphite, +metallic lead was employed for the purpose. Graphite was first used +in pencils after the discovery in 1565 of the famous Cumberland mine +in England. This graphite was of remarkable purity and could be used +without further treatment by cutting it into thin slabs and encasing +them in wood. + + +Who Made the First Lead-pencils in America? + +For two centuries England enjoyed practically a monopoly of the +lead-pencil industry. In the eighteenth century, however, the +lead-pencil industry had found its way into Germany. In 1761, Caspar +Faber, in the village of Stein, near the ancient city of Nuremberg, +Bavaria, started in a modest way the manufacture of lead-pencils, and +Nuremberg became and remained the center of the lead-pencil industry +for more than a century. For five generations Faber’s descendants made +lead-pencils. Up to the present day they have continued to devote +their interest and energy to the development and perfection of pencil +making. Eberhard Faber, a great-grandson of Caspar Faber, immigrated +to this country, and, in 1849, established himself in New York City. +In 1861, when the war tariff first went into effect, he erected his +own pencil factory in New York City, and thus became the pioneer of +the lead-pencil industry in this country. Since then four other firms +have established pencil factories here. Wages, as compared to those +paid in Germany, were very high, and Eberhard Faber realized the +necessity of creating labor-saving machinery to overcome this handicap. +Many automatic machines were invented which greatly simplified the +methods of pencil making and improved the product. To-day American +manufacturers supply nine-tenths of the home demand and have largely +entered into the competition of the world’s markets. + + +What Are Lead-pencils Made of? + +The principal raw materials that enter into the making of a +lead-pencil are graphite, clay, cedar and rubber. Although graphite +occurs in comparatively abundant quantities in many localities, it is +rarely of sufficient purity to be available for pencil making. Oxides +of iron, silicates and other impurities are found in the ore, all of +which must be carefully separated to insure a smooth, serviceable +material. The graphites found in Eastern Siberia, Mexico, Bohemia and +Ceylon are principally used by manufacturers. + + Pictures by courtesy Joseph Dixon Crucible Co. + +[Illustration: FIG. 1. + +FIG. 2. + +FIG. 3. + +Fig. 1 shows the shape in which the cedar slats arrive at the factory. +These slats after grading are boiled in steam to remove what remaining +sap there may be in the wood. The slats are then dried in steam-drying +rooms. Then the next step is grooving and gives the results shown by +Fig. 2. Now the wood is ready to receive the “leads” (which you will +remember are a mixture of graphite and clay), which are placed between +two slats sandwich fashion, glued, put in forms that hold them over +night under a thousand pounds pressure. Fig. 3 shows the leads laid in +one of the grooved slats.] + + +How Are Lead-pencils Made? + +The graphite, as it comes from the mines, is broken into small pieces, +the impure particles being separated by hand. It is then finely +divided in large pulverizers and placed in tubs of water, so that the +lighter particles of graphite float off from the heavier particles of +impurities. This separating, in the cheaper grades, is also done by +means of centrifugal machines, but the results are not as satisfactory. +After separation, the graphite is filtered through filter-presses. + + +What Makes Some Pencils Hard and Others Soft? + +The clay, after having been subjected to a similar process, is placed +in mixers with the graphite, in proportions dependent upon the grade +of hardness that is desired. A greater proportion of clay produces a +greater degree of hardness; a lesser proportion increases the softness. + +[Illustration: FIG. 4. + +FIG. 5. + +FIG. 6. + +Fig. 4 shows a prospective view of the block as it appears when taken +out of the form; the leads can be seen in the end. These blocks are fed +to machines which cut out the pencils in one operation. An idea of this +operation is given by Fig. 5, which shows a block half cut through. The +pencils come out quite smooth, but are sand-papered to a finer finish +before receiving the finishing coats. The finer grades of pencils are +given from seven to nine coats of varnish before being passed along for +the next process. Fig. 6 shows a pencil after it has been machined and +before it has been varnished and stamped.] + +Furthermore, the requisite degree of hardness is obtained by the +subsequent operation, viz., the compressing of the lead and shaping it +into form ready to be glued into the wood casings. A highly compressed +lead will produce a pencil of greater wearing qualities, an important +feature in a high-grade pencil. Hydraulic presses are used for this +purpose; and the mixture of clay and graphite, which is still in a +plastic condition and has been formed into loaves, is placed into these +presses. The presses are provided with a die conforming to the caliber +of the lead desired, through which die the material is forced. The die +is usually cut from a sapphire or emerald or other very hard mineral +substance, so that it will not wear away too quickly from the friction +of the lead. The lead leaves the press in one continuous string, which +is cut into the lengths required (usually seven inches for the ordinary +size of pencil), is placed in crucibles, and fired in muffle furnaces. +The lead is now ready for use, and receives only a wooden case to +convert it into a pencil. + + +Where Does the Wooden Part of a Lead-pencil Come from? + +The wood used in pencil making must be close and straight grained, +soft, so that it can readily be whittled, and capable of taking a good +polish. No better wood has been found than the red cedar, a native of +the United States, a durable, compact and fragrant wood to-day almost +exclusively used by pencil makers the world over. The best quality is +obtained from the Southern States, Florida and Alabama in particular. + +The wood is cut into slats about 7 inches long, 2¹⁄₂ inches wide, and +¹⁄₄ inch thick. It is then thoroughly dried in kilns to separate the +excess of moisture and resin and to prevent subsequent warping. After +this the slats are passed through automatic grooving machines, each +slat receiving six semi-circular grooves, into which the leads are +placed, while a second slab with similar grooves is brushed with glue +and covered over the slat containing the leads. This is passed through +a molding-machine, which turns out pencils shaped in the form desired, +round, hexagon, etc. The pencils are now passed through sanding +machines, to provide them with a smooth surface. + + +How is the Color Put on the Outside of the Pencil? + +After sand-papering, which is a necessary preliminary to the coloring +process, when fine finishes are desired, the pencils are varnished by +one of several methods. That most commonly employed is the mechanical +method by which the pencils are fed from hoppers one at a time through +small apertures just large enough to admit the pencil. The varnish is +applied to the pencil automatically while passing through, and the +pencils are then deposited on a long belt or drying pan. They are +carried slowly a distance of about twenty feet, the varnish deposited +on the pencils meanwhile drying, and are emptied into a receptacle. +When sufficient pencils have accumulated, they are taken back to the +hopper of the machine and the operation repeated. This is done as often +as is necessary to produce the desired finish. The better grades are +passed through ten times or more. Another method is that of dipping +in pans of varnish, the pencils being suspended by their ends from +frames, immersed their entire length and withdrawn very slowly by +machine. A smooth enameled effect is the result. The finest grades of +pencils are polished by hand. This work requires considerable deftness; +months of practice are necessary to develop a skilled workman. After +being varnished, the pencils are passed through machines by which the +accumulation of varnish is sand-papered from their ends. The ends +are then trimmed by very sharp knives to give them a clean, finished +appearance. + +Stamping is the next operation. The gold or silver leaf is cut into +narrow strips and laid on the pencil, whereupon the pencil is placed in +a stamping press, and the heated steel die brought in contact with the +leaf, causing the latter to adhere to the pencil where the letters of +the die touch. The surplus leaf is removed, and, after a final cleaning +the pencil is ready to be boxed, unless it is to be further embellished +by the addition of a metal tip and rubber, or other attachment. + + +How is the Eraser Put On a Pencil? + +In this country about nine-tenths of the pencils are provided with +rubber erasers. These are either glued into the wood with the lead, or +the pencils are provided with small metal ferrules threaded on one end, +into which the rubber eraser-plugs are inserted. These ferrules are +made from sheet brass, which is cupped by means of power presses, drawn +through subsequent operations into tubes of four- or five-inch lengths, +cut to the required size, threaded and nickel-plated. + +[Illustration: + + Courtesy of Doubleday, Page & Co. + +A SOUTHERN COTTON FIELD] + + + + +The Story in a Bale of Cotton + + +Where Does Cotton Come From? + +We get cotton from a plant which grows best in the warm climate of our +Southern States. Cotton has been known to the people of the world for +a long time. Before the birth of Christ people knew about cotton. They +thought it was wool which grew on a tree instead of a sheep’s back. +No other plant is of such value to man as cotton. We should learn +something about a plant that is used by man in so many ways as cotton. + +The cotton plant of our Southern States is a small shrub-like annual +about four feet high. The flowers of the cotton plant are white at +first but change to cream color and then are tinged with red. This +change takes place over a period of four days when the petals drop off +and leave what is called a “boll” in the calyx of the flower. This +boll, which is to contain the cotton, is really the seed container of +the cotton plant and keeps on growing larger until it is about as big +as a hen’s egg. When it is fully grown or ripe the boll cracks and the +seeds and fibrous lint burst forth. The bolls are then gathered and +taken to a cotton gin, where the seeds are separated from the lint and +the lint prepared for weaving. + +The boll is divided into from three to five sections. Each section +contains a quantity of lint and seeds. When the boll is fully grown +the covering of each of the sections cracks and opens up, revealing +the contents. It is just like opening the door of each section and +having the contents burst out. When these bolls burst open, there is no +more beautiful sight in the world than to look out over a cotton field +and see the colored people--the “cotton pickers”--busy at their work +picking off the bolls. + +When the crop is gathered and ginned, the lint is packed into bales and +taken to the cotton mill, where it is made into cloth. One of the most +interesting industrial processes in the world is to see the bale of +cotton go into a cotton mill and come out a piece of cotton goods. + +[Illustration: THE COTTON ARRIVES AT THE MILL + +BALES OF COTTON AT COTTON MILL] + +[Illustration: OPENING MACHINES. + +The bales are opened, and the cotton is thrown into the large hoppers +at the front of these machines, which open and loosen the fibers, +work out lumps and remove the grosser impurities, such as dirt, leaf, +seed and trash. A strong air draft carries off the dust and foreign +particles, and lifts the cotton through trunks to the floor above.] + +[Illustration: LAPPER MACHINES. + +In these machines, known as Breaker and Finisher Lappers, more of the +trash and impurities is beaten out of the cotton, and the lint is +carried forward and wound into rolls of cotton batting, known as laps. +Several of these are doubled and drawn into one so as to get the weight +of each yard as uniform as possible.] + +[Illustration: FIRST STEPS IN MAKING COTTON CLOTH + +CARD ROOM. + +In these machines, known as Revolving Flat Top Cards, the cotton passes +over revolving cylinders clothed with wire teeth, and the fibers are +combed out and laid parallel with each other. They are delivered at the +front of the machine as a filmy web, which is gathered together and +formed into a soft downy ribbon or rope, known as card sliver. This is +automatically coiled and delivered into cans.] + +[Illustration: DRAWING FRAMES. + +To insure uniformity in weight, so that the yarn when spun shall run +even, the card slivers are doubled and drawn out, redoubled and again +drawn out, somewhat in the manner of a candy maker pulling taffy, only +here the process is continuous. Six strands of the card sliver are fed +in together at the back of the drawing frames, pulled out and delivered +as one; and the process repeated. This produces a sliver more uniform +in weight, and in which the fibres are more parallel.] + +[Illustration: SLUBBERS. + +The sliver from the drawing frames is taken to machines called +slubbers, where again the fibers are drawn out, and the strand of +cotton, now much finer and known as slubber roving, is given a bit of +twist to hold it together, and is wound on large bobbins.] + +[Illustration: PUTTING THE COTTON FIBER ON BOBBINS + +SPEEDERS. + +The large bobbins of roving from the slubbers are taken to other +machines known as Speeders, and are unwound through the machine, again +drawn out finer and finer, and rewound on smaller bobbins. The strand +of cotton known as speeder roving is now ready to be taken to the +spinning room for the final draft and twist necessary to turn it into +yarn.] + +[Illustration: SPINNING FRAMES. + +The roving from the speeders is placed on the Spinning Frames, and now +undergoes its final draft as it passes through the spinning rolls. The +attenuated fibres are then twisted firmly together by the action of the +spindles, which turn at a speed of about 10,000 revolutions per minute. +The yarn thus formed is wound on bobbins and is ready to be dyed and +weaved.] + +[Illustration: THE COTTON IS READY FOR DYEING + +SPOOLERS. + +Two kinds of yarn are delivered at the spinning frames, known as warp +and filling, which make respectively the lengthwise and crosswise +threads of the cloth. The filling is in its completed form ready for +the loom; the warp must first be gotten into shape for dyeing and then +arranged in parallel rows or sheets of thread for weaving. The first of +these processes is spooling, and consists simply in unwinding the yarn +from the small bobbins on which it is spun, and rewinding it on large +spools.] + +[Illustration: WARPERS. + +The spools of warp yarn are placed in large wooden racks or creels from +which they can conveniently unwind. The separate threads are drawn +through little wires in the warpers, and are gathered into a bunch or +rope of threads, which is wound in a large cylindrical ball known as a +warp. If any thread breaks while passing through the warper, the little +wire drops and stops the machine. In this way full count of threads and +uniform weight of the goods is insured.] + +[Illustration: DYE-HOUSE. + +Here the warps, after being boiled and softened to enable the dye to +penetrate, are passed through the indigo vats. Several runs are made to +get the beautiful depth of color. This Dye-house is equipped with one +hundred indigo vats, and is one of the best-lighted and cleanest-kept +dye-houses in the world.] + +[Illustration: WHERE THE COTTON IS WOVEN INTO CLOTH + +BEAMING FRAMES. + +After being dyed, the warps are washed and then passed through drying +machinery, from which they are delivered in coils. These are brought +to the beaming frames, where they are again spread out into sheets of +parallel threads, and passed through the teeth of a steel comb, which +separates the threads and prevents tangling, and in this form they are +wound on huge iron spools known as slasher beams.] + +[Illustration: SLASHERS. + +From the beaming frames the warps are taken to machines known as +Slashers, where they are sized or stiffened to enable them to stand the +chafing at the looms incidental to the process of weaving. The slasher +beams are placed in an iron frame at the back of the slashers and +unwound together through the machine. With them some additional threads +of white yarn are unwound at either side to form the selvage of the +cloth.] + +[Illustration: WEAVE ROOM. + +The sheet of warp threads unwinds from the loom beam, receives the +filling threads and is wound into a roll of cloth at the front of the +loom. This weave room contains 2000 looms. It is 904 feet long by 180 +feet wide (about four acres) and is the largest single weave room in +the world. Overhead is the roof, which forms one vast sky-light, being +of what is known as saw-tooth construction. The vertical sides of the +teeth all face due north and are formed of ribbed glass, which affords +the most perfect light to every section of the room.] + +[Illustration: THE COTTON CLOTH FINISHED + +INSPECTING TABLES. + +Before going to the baling presses every yard of cotton cloth passes +under the vigilant eyes of the cloth inspectors, who mark as seconds +and lay aside all pieces containing imperfections. This inspection +is not a mere formality, but is conducted most carefully, and this +department is specially located to get the best and most perfect light.] + +[Illustration: BALING PRESSES. + +The bolts of finished cloth are now placed in presses and made into +bales of finished cloth and are ready for the market.] + +[Illustration: Shipping platform of the White Oak Mills, Greensboro, N. +C., showing how the bales of finished cloth are handled in shipping.] + + Pictures herewith by courtesy of White Oak Mills. + + +Who Discovered Cotton? + +Just who discovered cotton is not known. The early records are so +incomplete that no individual can be credited with the discovery of +the value of this wonderful plant. Long before Cæsar’s time, among the +Hindoos they had a law that if you stole a piece of cotton you were +fined three times its value. Most of the early nations were familiar +with cotton--the early Egyptians, Chinese and other ancient people used +it and valued it. + + +What Nation Produces the Most Cotton? + +The United States is the leader in the production of cotton, as in many +other important world products. We produce more than seventy-five per +cent of all the cotton grown in the world. The remainder is practically +all grown by East India, Egypt and Brazil. + + +What is Cotton Used For? + +The cotton plant is one of the wonder plants of the world, when you +stop to think how well we could get along without wool or silk or other +fabrics if we had to. + +Little would be lost to the world so far as actual comfort is concerned +if all of the other fabric-making materials were lost. We would sleep, +as we often do now, in beds the coverings of which were pure cotton, +in a room in which the rugs were woven from cotton, the sun kept out +of the room by cotton window shades. We could still have plenty of +good soap to wash our bodies and clothing, for much of our soap to-day +is made from cotton-seed oil; then we could use a cotton towel to dry +ourselves; and put on a complete outfit of clothing made entirely of +cotton. White cotton table cloths and napkins are not so fine as linen; +they are good enough for anyone. Your breakfast rolls will taste quite +as well if baked with cottolene instead of lard; the meat for your +dinner would be fed and fattened on cotton-seed meal and hulls as they +are now; you would have butter made from cotton-seed that compares +favorably with the butter you now have on the table; the tobacco in +your cigar would continue to be grown under cotton cloth and packed in +cotton bags; armies would still sleep under cotton tents and could use +gun-cotton to destroy the enemy. + + +What Are the Principal Cotton Cloths? + +There are a great many different names given to cotton cloths, but +they may in general be divided into five classes--plain goods, twills, +sateen, fancy cloth and jacquard fabrics. The cotton cloth in each of +these classes varies and goes by different names. For instance, in +Plain Goods, the different kinds are lawn, nainsook, sheeting, mull, +print cloth, madras. The difference lies in the number of threads in +one inch of width, the fineness and the weave. The Twills have lines +running diagonally and are used for linings mostly. The difference +is in the weaving. Denim, largely used for overalls, belongs to the +class of Twills. Sateen is used for dress linings, dresses and waists. +Then there is the class of Fancy Cloths which is another kind of weave +used largely in children’s clothes, shirt waists, etc., and under +the name Scrim is fine for draperies and towelling. The other class, +Jacquard Fabrics, represents the most complicated form of weaving and +used largely under special individual names or brands for dress goods, +novelties, etc. + + +How Much Cotton Cloth Will a Pound of Cotton Make? + +When the cotton is spun into yarn it is no longer sold by the bale, but +by the pound. It is impossible to make an exact statement of the amount +of cotton cloth one pound of cotton yarn will make, because of the +difference in weaving. It has, however, been figured out that a pound +of cotton yarn should make + + 3¹⁄₂ yards of sheeting, or + 3³⁄₄ yards of muslin, or + 9¹⁄₂ yards of lawn, or + 7¹⁄₂ yards of calico, or + 5¹⁄₂ yards of gingham, or + 57 spools of thread. + +[Illustration: + + Picture by courtesy Browne & Howell Co. + +CHRISTOFORI PIANO FROM THE METROPOLITAN MUSEUM OF ART, NEW YORK CITY.] + + + + +The Story in a Piano + + +What is Music? + +Music is one kind of sound. All sounds, whether musical or not, are the +result of sound waves in the air. They travel almost exactly like the +waves of the water. They go in circles in all directions at the same +speed and will go on forever unless they meet something that has the +ability to stop them. If you drop a pebble into the exact center of a +basin of water, you will see the ring of waves produced start from the +point where the pebble entered the water and travel to the sides of the +vessel, which stop them. Also the pebble as it falls into the water +will make ring after ring of waves. + +When you shout or ring or strike one of the keys of the piano you start +a sound wave or a series of them, which you can hear as soon as the +sound wave strikes your ear. When the series of waves is regular the +sound produced is a musical sound, and when the sound waves are not +regular in length we call it some other kind of a sound. + +Acting on the knowledge so learned, man has devised numerous +instruments with which he can produce musical sounds, such as the +piano, phonograph, and many others. + + +Who Made the First Piano? + +The first real piano was made by Bartolomeo Christofori, an Italian. +He invented the little hammers by the aid of which the strings are +struck, giving a clear tone instead of the scratching sound which +all the previous instruments produced. It took two thousand years to +discover the value of the little hammers in making clearer notes. His +first piano was made in 1709. The word by which we call the instrument +pianoforte has, however, been traced back as far as 1598, when it is +said to have been originated by an Italian named Paliarino. The first +piano made in America was produced by John Behnud, in Philadelphia, in +1775. + + +How Was the Piano Discovered? + +~THE DISCOVERY OF STRINGED MUSICAL INSTRUMENTS~ + +The piano is a stringed musical instrument. The name pianoforte comes +from two Italian words meaning _soft_ and _loud_, and is accurately +descriptive of the piano because the notes can at will be made soft or +loud. The piano is a development of the simplest form of making regular +sound vibrations by snapping or hammering a string of some kind which +is stretched tight and fastened at both ends. We must go far back into +history to find the earliest traces of stringed instruments, and even +then we do not know where and when they originated, for there seem to +be no records which help us to trace their origin. We know that the +Egyptians as far back as 525 B.C. had stringed instruments, but we only +know they had them--not where they got them or who made them. There +is a legend that the Roman god Mercury, while walking along the Nile +after the river had overflowed its banks and the land had again become +dry, stubbed his toe on the shell of a dead tortoise. He picked it up +to cast it aside and accidentally touched some strings of sinew with +his finger. These strings were only what remained of the once live +tortoise. At the same time Mercury heard a musical note and, after +vainly trying to find a cause for the musical sound, twanged the string +again and discovered the music in tightly-stretched strings. He set +about making an instrument, using the tortoise shell for the sound box +and stretching a number of strings of sinew across it. This is only a +legend, of course, but if we examine the early musical instruments of +the Greeks, which was the lyre, we always find the representation of a +tortoise upon it. + +Other nations, such as the early Chinese, the Persians, the Hindus and +the Hebrews, had stringed instruments much resembling the lyre. In the +tombs of the great rulers of Egypt are found representations of harps, +and one harp which had been buried in one of the tombs for more than +3000 years was actually found to be in good condition. + +[Illustration: Picture by courtesy Browne & Howell Co. + +DULCIMER.] + +Wherever we search among the records of early nations we find evidence +that they were familiar with the music obtainable from playing upon +stringed instruments, but we have never been able to discover what +people or what persons first learned that music could be produced with +such instruments. + +~THE FIRST STRINGED MUSICAL INSTRUMENT~ + +The harp was probably the first practical stringed instrument. Its +music was produced by picking the strings with the fingers or with a +piece of bone or metal. + +The next step was the psaltery, which was produced in the Middle Ages. +It was a box with strings stretched across it and represented the first +crude attempt at using a sounding board. A larger instrument which came +about the same time and was very like the psaltery, was the dulcimer. +Both were played by picking the strings with the finger or a small +piece of bone or other substance. + +Then came the keyboard, first used on stringed instruments in what +is called the _clavicytherium_. This consisted of a box with cat-gut +strings ranged in a semitriangle. On the end of each key was a quill, +which picked the string when the key was operated. + +After this came the clavichord. It was built like a small square piano +without legs. The strings were made of brass and on the end of each key +was a wedge-shaped piece of brass which picked the strings. The elder +Bach composed his music on the clavichord, his favorite instrument, and +that is why the music written by Bach is full of soft and melancholy +notes. The clavichord produced only such notes. + +The next steps brought the virginal, spinet and harpsichord. The +strings on all three were of brass with quills at the key ends for +picking the strings. The virginal and spinet were very much alike. The +harpsichord was larger and sometimes was made with two keyboards. These +instruments had notes covering four octaves only. + +[Illustration: Picture by courtesy Browne & Howell Co. + +CLAVICHORD.] + +The arrangement of the strings in the harpsichord provided one step +nearer to our piano. It had five octaves of notes and there were at +least two strings to each note instead of only one, as in previous +instruments. + +[Illustration: Picture by courtesy Browne & Howell Co. + +SPINET.] + + +Why Do We Have Only Seven Octaves On a Piano? Why Not Twelve or More +Octaves? + +Ordinarily the longest key-board of the piano has seven octaves and +three notes in addition, or 52 notes, not counting the sharps and +flats. An octave you, of course, know consists of the seven notes C D +E F G A B. Every eighth note is a repetition of the one seven notes +below or above. The reason that there are no more notes or octaves on +the piano is that if we extended the key-board either way one or two +octaves more, we should not be able to hear the notes struck on the +keys. There would be sound produced, or course, but the vibrations +would be too fine for the human ear to hear. It is said that the range +of the human ear does not go beyond somewhere between eleven and twelve +octaves. + +[Illustration: Picture by courtesy Browne & Howell Co. + +UPRIGHT HARPSICHORD. + +(From the Metropolitan Museum of Art, New York City.)] + +[Illustration: + + Picture by courtesy Browne & Howell Co. + +QUEEN ELIZABETH’S VIRGINAL.] + +[Illustration: HOW THE MUSIC GETS INTO THE PIANO + + Photo by Kohler & Campbell Piano Co. + +PUTTING ON THE SOUNDING BOARD. + +The first operation in producing the piano is to make a wooden frame +or back on which is attached first the sounding board, then the iron, +harp-shaped frame to which the strings are fastened. + +The tones of the piano are produced by felt-covered hammers striking +the strings. The sounding board, which is made of wood, magnifies the +tones. + +This picture shows the mechanics glueing the sounding board to the +back.] + +[Illustration: + + Photo by Kohler & Campbell Piano Co. + +FASTENING THE STRINGS. + +The strings are hitched on to pins in the iron frame at its lower end +and fastened at the upper end by a metal pin or peg driven into the +back. The peg is square on top, so that it can be turned with a tuning +hammer or wrench in order to tighten or slacken the strings, which is +the operation of tuning the piano.] + +[Illustration: THE LITTLE HAMMERS WHICH STRIKE THE PIANO STRINGS + + Photo by Kohler & Campbell Piano Co. + +BUILDING THE CASE AROUND THE SOUNDING BOARD. + +As soon as the sounding board with its iron frame and strings is +complete, the outside case is built up around it, the front being left +open to receive the action and key-board.] + +[Illustration: + + Photo by Kohler & Campbell Piano Co. + +ATTACHING THE LITTLE HAMMERS THAT STRIKE THE STRINGS. + +In this picture the workmen are placing the action and keys, to which +are attached the little wooden felt-covered hammers, which will strike +the strings and produce the tones. It took a great many years for our +musical instrument makers to hit upon the idea of using these little +hammers, and thus make the piano a perfect instrument.] + +[Illustration: REGULATING THE ACTION OF THE PIANO + + Photo by Kohler & Campbell Piano Co. + +REGULATING THE ACTION AND KEYBOARD. + +This picture shows the piano partly assembled and the workmen adjusting +each little black and white key to the proper touch.] + +[Illustration: + + Photo by Kohler & Campbell Piano Co. + +TUNING, POLISHING AND FINISHING. + +The piano is now complete except for polishing and tuning. The tuning +is left to the last. The tuner must have a good ear for music. With +his key he tightens or loosens each of the pegs to which the wires are +attached until it is perfectly in tune and all in harmony. The piano is +now ready to play upon.] + + + + +How Sounds Are Produced. + + +If you look closely at a tuning fork, or a piano string, while it +is sounding, you can see that it is swinging rapidly to and fro, or +vibrating. Touch it with your finger and thus stop its vibration and it +no longer produces sound. The only difference that you can discover in +the fork or string when sounding and when silent is that when you stop +the motion it is silent and when it vibrates it makes a sound. From +this we learn that the sounds are due to the vibrations of sounding +bodies. This has been proven by the examination of so many sounding +bodies that we believe that all sounds are produced by vibrations. + +The question that next presents itself is, how the vibrations affect +our ears, so as to produce the sensation of hearing. This may be made +clear by a very simple, but striking, experiment. If a bell which has +been arranged to be rung by clock-work is suspended under the receiver +of an air pump, and the air pumped out, the sound of the bell will grow +faint as the quantity of air in the receiver decreases, and finally +will stop completely. By looking through the glass of the receiver, +however, the bell may be seen ringing as vigorously as at first. We +learn thus that the air around a sounding body plays an important part +in the transmission of the vibrations to our ears. The way in which +the air acts in transmitting the vibrations is as follows. At each +vibration of the sounding body, it compresses, to a certain degree, +a layer of air in front of it. This layer, however, does not remain +compressed, for air is very elastic, and the compressed air soon +expands, and in doing so compresses a layer of air just beyond it. This +layer expands in its turn, and compresses another layer still further +from the body. In this way waves of compression are sent through the +air, at each vibration, in all directions from the vibrating body. + +It must not be thought that particles of air travel all the way from +the vibrating body to the ear when a sound is heard. Each particle of +air travels a very short distance, never any further than the vibrating +body moves in making a vibration, and the movement of the air particles +is a vibratory one, like that of the sounding body. But the particles +of air near the sounding body communicate their vibrations to other +particles, further from that body, and these, in turn, to others still +further away, so, while the particles of air themselves move very short +distances, the waves produced by their vibrations may be made to travel +a considerable distance. + +The size of a sound wave ordinarily is very small, but sound waves are +sometimes made of such size and strength as to strike our ears with +a force sufficient to rupture the ear drum. Such large and forceful +waves come during explosions, such as the discharges of cannon or the +explosions of large quantities of gunpowder under any conditions. + + + + +What Is Sound? + + +From what has already been said, you will probably answer that sounds +are waves in the air, which produce the sensation of hearing. This +is correct, but sound is not limited to vibrations of the air. Other +elastic substances can be made to vibrate in the same way, and the +waves so produced when conveyed to our ears, produce the sensation of +hearing. If you put your ear under water and then strike two stones +together in the water you will hear a sound as readily as you would in +air. Sound waves may be transmitted by solid bodies also, and some of +these are better for this purpose than air or liquids. Perhaps you have +tried the experiment of placing your ear against one of the steel rails +on a railroad track to listen for the coming of a distant train. If you +have tried this, you know that a sound that is too faint, or is made +too far away, to be heard through the air, can easily be heard through +the rail. + +In view of the fact that other substances than air can be thrown into +waves that will affect the sense of hearing, we may define sound as +vibrations in any elastic object, that produces the sensation of +hearing. + +The definition is sometimes called the physical definition of sound, +in contradistinction to the physiological definition of sound which +is given as the sensation produced when vibrations in elastic +substances are conveyed to our ears. You will see then that sound when +referring to the physical definition is what makes sound known in the +physiological definition. The term sound alone, without qualifications, +may have either meaning, and therefore statements concerning sound may +be misleading, unless we are exact in explaining the sense in which the +word is used. + + + + +How Fast Does Sound Travel? + + +When a sound is made close to us, it reaches our ears so quickly that +it seems as though it took no time to travel; but when a gun is fired +by a person at a distance, you will notice that after you see the flash +of the gun, a little time elapses before the sound reaches your ear. It +takes a little time for the light from the flash to get to your eyes, +but a very short time, which you cannot appreciate. Sound travels much +more slowly and the time it takes to travel a few hundred yards is +noticeable. Accurate measurements of the speed of sound have been made, +and it has been found that sound usually travels in air at a speed of +about eleven hundred feet a second. The speed is not always the same, +however, for a number of circumstances may cause it to vary. In air +which is heated, the speed at which sound travels in it is increased +because hot air expands. At the freezing point, sound travels through +the air at the rate of 1,091 feet a second, and for every increase +in temperature of one degree of heat, the speed is increased about +thirteen inches a second. Accordingly at 68° F. the speed would be +approximately 1,130 feet a second. Sounds also travel faster in moist +air than in dry. + +In other gases the speed of sound transmission may be greater or less +than in air. For example, in hydrogen gas, which is much lighter than +air, sound travels nearly four times as fast as it does in air. On the +other hand, in carbonic acid gas, which is heavier than air, sound is +transmitted more slowly. + +In liquids, which are always heavier than air, you would naturally +think that sound would travel more slowly than in air, but this is not +true. Liquids are less compressible than gases and this causes the +speed with which sound is transmitted in them to be increased. In water +sound travels about four times as fast as in air. + + + + +What Are the Properties of Sound? + + +Sounds differ from each other by the extent to which they possess three +qualities, namely; intensity, pitch and quality. + +The intensity of any sound that we hear depends upon the size of +the waves that reach our ears. The size of a sound wave gradually +decreases, as the wave travels from its starting point, consequently +the intensity of a sound depends upon the distance from the point +at which the sound was produced. We know this from experience and +if we think of the matter for a moment we will see why it is so. At +the start of a sound wave, only a small quantity of air is affected, +but for every inch it travels the quantity of air to which the wave +is conveyed becomes larger, and the intensity of the waves must grow +correspondingly smaller, just as when a pebble is dropped into water, +the ripples produced by it are highest at the point where the pebble +struck the water, and grows lower and lower as their circle widens. + +It has been found possible to measure the intensity of a sound wave, +at different distances from the point from which it started, and from +these measurements it has been learned that the decrease in the open +air, follows a fixed rule that is stated thus: the intensity of a +sound wave at any point is inversely proportional to the square of +its distance from its starting point. This rule is called “the law +of inverse square,” and it means that if the intensity of a wave be +measured at two points, distant say one hundred, and two hundred yards, +respectively, from the starting point of the sound, the intensity of +the sound at the first point will be found to be four times as great as +at the second point. + + + + +Why Can You Hear More Easily Through a Speaking Tube? + + +We have seen that the decrease in intensity of a sound wave as it +travels through the air, is due to the fact that the quantity of +air set in motion by it is constantly increasing. But, if a wave is +conveyed through a tube containing air, the quantity of air to which +the vibrations are communicated does not increase as the wave travels +forward, and theoretically there is no decrease in intensity. When a +wave is actually transmitted in this way, however, it is found that +there is some decrease in intensity on account of the friction of the +particles of air against the sides of the tube; but the decrease from +this cause is much slower than that which occurs in the open air, and +consequently sounds can be heard at much greater distances through +tubes than through the open air. Tubes for speaking purposes are +frequently used to connect different parts of the same building, and if +the tubes are not too crooked they serve their purpose very well. + +Pitch is that property of sounds that determines whether they are high +or low. The pitch of a sound depends upon the number of vibrations +a second which the body that produces it makes. The sound of an +explosion has no pitch because it makes but one wave in the air. The +sound made by a wagon on a pavement has no definite pitch, for it is +a mixture of sounds, in which the number of vibrations per second is +not the same. Pitch is a property of continuous sounds only, and it is +apparent chiefly in musical sounds, by which we mean sounds in which +the vibrations are continuous and regular. In music, however, pitch +is very important. In a musical instrument, the parts are so arranged +that the sounds produced can be given any desired pitch, and it is by +controlling the pitch that the pleasing effect of musical sounds in +large measure is produced. Sounds of low pitch are produced by bodies +making but a few vibrations a second while high-pitched sounds are made +by bodies that vibrate rapidly. + +Quality, may be defined as that property of sounds which enable us to +distinguish the notes produced by different instruments. Two notes, +one of which is produced upon a piano, and the other upon a violin, +may have the same pitch and be equally loud, yet they are easily +distinguishable. The difference in them is due to the presence of what +are called overtones. + + + + +What Is Meant By the Length of Sound Waves? + + +The length of a sound wave embraces the distance from the point of +greatest compression in one wave to the same point in the next. This +depends upon the pitch for if a sounding body is making one hundred +vibrations a second, by the time the one hundredth vibration is made, +the wave from the first vibration will have travelled about eleven +hundred feet from the starting point, and the remaining ninety-eight +waves will lie between the first and the one hundredth. In consequence +of this, the wave length for that particular sound will be about eleven +feet. If the sounding body had made eleven hundred vibrations a second +by the time the first wave had travelled eleven hundred feet, there +would have been eleven hundred waves produced, and the wave length for +that sound would be one foot. The wave lengths of sounds produced by +the human voice usually lay between one and eight feet, though some +singers have produced notes having wave lengths as great as eighteen +feet, and others have reached notes so high that the wave length was +only about nine inches. + +When a tuning fork is struck, it produces a sound so faint that it can +scarcely be heard unless the fork is held near the ear; but if the end +of the fork is held on a box or table, the sound rings out loudly and +seems to come from the table. The explanation of this is very simple. +When only the fork vibrates, it produces very small sound waves, +because its prongs are small and cut through the air. But when it is +set on a box or table, its vibrations are communicated to the support, +and the broader surface of the box or table sets a larger mass of air +in vibration, and so amplifies the sound of the fork. When a surface +is used in this way to reinforce the vibrations of a small body, and +thus produce sound waves of greater volume, it is called a sounding +board. Many musical instruments, like the violin and the piano, owe +the intensity of their sounds to sounding boards, which reinforce the +vibrations of their strings. + +~WHAT A SOUNDING BOARD DOES~ + +Columns of air, like sounding boards, serve to reinforce sound waves. +Unlike sounding boards, however, they do not respond equally well to a +large number of different sounds. They respond to one sound only, or +to several widely different ones. This may be shown as follows: Take a +glass tube about sixteen inches long, and two inches in diameter, and +after thrusting one end of it into a vessel of water, hold a vibrating +tuning fork over the other end. By gradually lowering the tube into the +water a point will be reached at which the sound becomes very loud, and +as this point is passed the sound gradually dies away again. By raising +the tube again the sound is again made loud when the tube reaches a +certain point. This shows that to reinforce sound waves of a certain +vibration frequency, the column of air in the tube must be of certain +length. + +Let us now see why the waves produced by the tuning fork are reinforced +only by a column of air of a certain length. When the prongs of the +fork make a vibration, a wave of air is produced which enters the tube, +goes down to the water, is reflected, and comes back toward the fork. +Now, if the reflected wave reaches the fork at the precise moment when +it has completed one-half of its vibration and is about to begin upon +the second half, it will strengthen the wave produced by the second +half of the vibration; but if the reflected wave reaches the fork +before or after the beginning of the second half of the vibration, it +will not reinforce it. At the downward movement of the lower prong of +the tuning fork, a wave of compression is sent down into the tube, and +is reflected at the surface of the water. In order to reinforce the +wave produced by the prong when it moves upward, the reflected wave +must reach the fork just at the time that the prong reaches its normal +position and before it starts upon the second half of its vibration. + +Not only do columns of air tend to reinforce notes having a certain +rate of vibration, but all elastic bodies have a certain rate at which +they tend to vibrate, and when sounds having the same rate of vibration +are produced near them, these bodies will vibrate in sympathy with +them. If the sounds be kept up long enough, the sympathetic vibrations +in objects near them sometimes become so great that they can easily be +seen. Goblets and tumblers made of thin glass show this property very +strikingly. When the proper notes are sounded the glasses take up the +vibrations, and give a sound of the same pitch. If the note is loud, +and is continued for some time, the vibrations of a glass sometimes +become so great that the glass breaks. Large buildings, and bridges +also, have rates at which they tend to vibrate, and this fact is the +foundation for the old saying, that a man may fiddle a bridge down, if +he fiddles long enough. + + + + +Musical Instruments. + + +By musical sounds, are meant sounds that are pleasant to hear, and +their combination in such a way that their effect is agreeable +produces music. Any instrument, therefore, that is capable of producing +pleasing sounds may be called a musical instrument, and music is +sometimes produced by very odd devices; but by musical instruments we +ordinarily mean instruments that are especially designed to produce +musical sounds. The number of such instruments that have been invented +is enormous, but all of them may be divided into comparatively few +classes, only two of which are of much importance. The two classes, +only two of which are of much importance. The two classes referred to +are stringed instruments and wind instruments. + +~WHAT PITCH IS IN MUSIC~ + +Stringed musical instruments are those in which the sounds are produced +by the vibration of a number of strings, and are generally reinforced +by a sounding board. The strings are arranged in the instruments in +such a way that the pitch of the sound produced by each string shall +bear relation to the pitch of those obtained from the other strings. As +long as this relation exists, the instrument is said to be in tune, and +when the relation is destroyed, the instrument is out of tune, and the +music produced by it is apt to contain what we call discords. + +The conditions that determine the pitch of sounds produced by strings +can be very easily discovered by experiment. Thus, by taking two pieces +of the same wire, one twice as long as the other, and stretching them +equally, you will observe on striking them that the shorter one yields +the higher note. If their vibration frequencies are measured it will +be found that the shorter string has a vibration frequency just twice +as great as that of the longer string. From this we conclude that when +two strings of the same size (and material) are stretched equally taut, +their vibration frequencies are inversely proportional to their lengths. + +By now taking two pieces of wire, of the same size and length, and +stretching them so that the tension of one is four times as great as +that of the other, we shall find that the vibration frequency of the +tighter string is just twice as great as that of the looser. Thus, we +see that the vibration frequency depends upon the tension applied to a +string, and, that in strings of the same size and length, the vibration +frequencies are proportional to the square roots of their tensions. + +Now taking two strings of the same length, but with the diameter of one +twice as great as that of the other, and stretching them equally, we +shall find that the vibration frequency of the smaller string is twice +that of the larger; which shows that when the lengths and tensions +of two strings are equal, their vibration frequencies are inversely +proportional to their diameters. + +In constructing stringed instruments, advantage is taken of each +of these conditions that affect the vibration of strings, and the +requisite pitch is secured in a string by choosing one of convenient +length and diameter, and by stretching it to just the right tension. + +When a string is plucked in the middle, it vibrates as a whole, and +its rate of vibration, or vibration frequency, is determined by the +three conditions that have just been discussed; but if a finger is +laid on the string, in the middle, and the string is plucked between +the middle and the end, the string will vibrate in halves, and the +middle point will remain at rest. If the string had been touched at a +point one-fourth of the length from the end it would have vibrated in +fourths, and there would have been three stationary points. + +When vibrations are set up in a string, with nothing to prevent the +free vibration of the whole string, it first vibrates as a whole, and +the sound produced is known as the fundamental tone of the string; but +very soon smaller vibrations of segments of the string begin, first +of halves of the string, then of thirds, and then of fourths. These +smaller vibrations produce sound waves that blend with the fundamental +tone and are known as overtones. The combined sound of the fundamental +tone and the overtones is called a note. The overtones present in +notes that have the same fundamental tone are not the same when the +notes are produced by different instruments, and, consequently, +the sound of notes of the same pitch is not the same on different +instruments. This difference in notes of the same pitch has already +been mentioned, but the way in which overtones are produced was not +explained in connection with it. + +In wind instruments the sounds are produced by the vibrations of +columns of air in pipes. In the organ, which is probably the best +example of a wind instrument, the vibrations are usually produced by +causing a current of air to strike a sharp edge, just above the opening +of the pipe, as is done in a common whistle. A portion of the air +current is deflected into the organ pipe, and it sets up vibrations in +the air within the pipe. + +The pitch of the sound produced by an organ pipe is determined by the +length of the pipe. A pipe that is open at both ends, called an open +pipe, produces a sound that has a wave length twice as great as the +length of the pipe; and if the pipe is open at one end only, a closed +pipe, the sound produced has a wave length twice the length of the open +pipe. Hence it will be seen that a closed pipe produces a sound that +has the same pitch as that produced by an open pipe that is twice as +long. + + + + +Talking Machines. + + +The phonograph, graphophone, gramophone, sonophone, and other talking +machines, furnish one of the best proofs of the wave theory of sound, +because their invention was based upon that theory. The first talking +machine was that invented by Thomas A. Edison and called by him the +phonograph. The others merely show the principle of the phonograph +applied in different ways, and need not be separately described. The +reasoning that led Edison to invent the phonograph was that if the +sound waves produced by the human voice were allowed to strike a thick +disk of hard rubber or metal, they would cause the disk to vibrate in +a certain way, and if the disk were again made to vibrate as it had +done under the influence of the voice, the sounds of the voice would be +reproduced. The difficult part of the task of making a talking machine +was in finding a way to make the disk vibrate again as it did under +the influence of the voice. This, however, was finally accomplished, +providing the disk with a needle, that rests on a cylinder of hard +wax, which turns slowly under the point of the needle while the sound +waves are striking the disk. The vibrations of the disk cause the point +to indent the surface of the wax so as to produce a groove of varying +depth on its surface. After the vibrations of the speaker’s voice have +been recorded in this way on the surface of the wax cylinder the needle +can be made to retrace its path, and will cause the disk to vibrate as +it did under the tones of the speaker’s voice. These last vibrations of +the disk produce sound waves similar to those of the voice, but their +amplitude is less and the sound is not so loud. + + + + +Why Does Red Make a Bull Angry? + + +It is very doubtful if a red flag really makes a bull more excited or +more quickly than a rag of any other color or any other object which +the bull can see plainly but does not understand. Conceding for the +moment that red excites a bull more than any other color, the answer to +the question will be found in the statement that anything unusual which +the bull sees has a tendency to make him angry and the thing which he +can see at a distance more quickly will start him going most quickly. +He can see a red rag better perhaps than almost any other color. There +may be something about the color which excites him just as some notes +on the piano will worry some dogs, but there is no way of studying the +bull’s anatomy to determine why red should excite him more than any +other color, if that is so. + +[Illustration: FIG. 1.] + +[Illustration: FIG. 2.] + +[Illustration: FIG. 3.] + + + + +HOW A KEY TURNS A LOCK + + +What Happens When the Knob is Turned? + +All of that portion of the lock which is shown above the round central +post is operated by the knob, the spindle of which passes through the +square hole. Before the knob is turned, the parts are in the position +shown in figure 2, with the latch bolt protruding. Turning the knob to +the left gives the position shown in figure 1, the upper lever in the +hub pushing back the yoke, which in turn pushes back the latch bolt. +When the hand is removed, the springs cause the parts to return to the +position shown in figure 2. Turning the knob to the right also retracts +the latch bolt, as shown in figure 3, by means of the lower lever on +the hub. + +The spiral spring on the latch bolt is lighter than the one above +it. This gives an easy, lively action to the bolt, with very little +friction when the door is closed, while the heavier spring above gives +a quick and positive action of the knobs. + + +What Happens When the Key is Turned? + +All of that portion of the lock which is shown below the round central +post is operated by the key. The square stud is attached to the bolt, +and in figure 1, it is seen that the projections on the flat tumblers +prevent the stud from moving forward, holding the bolt in retracted +position. When the key is turned as shown in figure 2, it raises the +tumblers releasing the stud, and then pushes the bolt out, the tumblers +falling into position as shown in figure 3, with the projections +again engaging the stud and preventing the bolt from moving until the +key is turned backward, again raising the tumblers and releasing and +retracting the bolt. + + +How Key Changes Are Provided. + +There are three ways in which keys are made individual to the locks +they fit. + +_a._ By changing the shape of the keyhole. This may be done shorter or +longer, wide or narrow, straight or tapering and with projections on +the sides which the key must fit, making it difficult or impossible +for keys of a different class to enter the lock. In the lock shown, a +projection on the keyhole will be noted, fitting a groove in the bit of +the key. + +_b._ By wards attached to the lock-case. The two crescent-shaped wards +seen near the key in figure 2 illustrate this feature. Similar wards +are placed on the lock cover. These fit into the two notches shown on +the key bit in figure 4, and their shape and position are varied at +will. + +_c._ By changes in the tumblers. There are five flat tumblers in the +lock shown, and their lower edges fit into the end of the key bit. +By varying their height, changes in the cutting of the key are made +necessary. + +The security of a lock depends very largely upon its being so made that +no key will operate it except the one which belongs to it, and this +is obtained by guarding the keyhole by means of _a_, by preventing +the wrong key from turning by means of _b_, and by still further +limitations by means of _c_. + +[Illustration: HOW A CYLINDER LOCK WORKS] + +[Illustration: FIGURE 1. PARTS OF CYLINDER LOCK.] + +[Illustration: FIGURE 2. + +FACE OF CYLINDER LOCK.] + + +The Cylinder Lock. + +Door locks of the highest grade of security are made with a locking +cylinder, which contains tumblers in the form of miniature bolts which +make it impossible to operate the lock except with the key to which it +is fitted. This is screwed into the lock-case through the side of the +door, with the lever on the inner end engaging the end of the bolt in +the lock, so that as it is moved it either retracts or “throws” the +bolt as desired. + +Figure 1 shows all the parts of a modern master-keyed lock. Figure +4 shows a broken view of the cylinder with all parts in position. +Figure 3 shows a simpler form used when the master key is not desired. +Figure 2 shows the front, the only part which is visible when the lock +is in use, with its keyway of tortuous shape which will not admit +flat-picking tools. + +When the lock is assembled, the pin tumblers project through the shell, +the master cylinder and the key plug holding all parts firmly bolted or +fastened together. When the proper key is inserted, the tumblers are +raised until the “breaks” in all of them coincide with the surface of +the key plug, releasing it and permitting the key to turn it. If any +one of the five tumblers is .002 inch too high or too low, the key will +not turn; so that no key except the one made for the lock can be used. + +In the master-keyed lock, the master key causes the breaks to coincide +with the outer surface of the master ring. It is thus possible to +have a master key which will fit any desired number of locks with the +individual or change keys all different from each other and from the +master key. + +The balls reduce friction to such an extent that a key has been +inserted and withdrawn for a million times without affecting the +accuracy of the lock. + +[Illustration: FIGURE 3. + +INTERIOR OF CYLINDER LOCK WITHOUT MASTER KEY.] + +[Illustration: FIGURE 4. + +INTERIOR OF MASTER-KEYED CYLINDER LOCK.] + + + + +Where Does Salt Come From? + + +Salt is one of the things with which we come in contact with daily +perhaps more than any other. With the exception of water, probably no +one thing is used more by all civilized people than salt. + +You have already learned in our talk on elements the difference between +a mere mixture of substances and a chemical compound. You remember +that when some substances are only mixed together, they do not lose +their identity. In a compound the substances are always combined in +fixed proportions and the properties of the compound are often very +different from those of the things that make it. Common salt is made of +two substances, that are not at all like salt, and are very different +from each other. One, sodium, is a soft, bluish metal, and the other is +chlorine, a yellowish-green gas. The chemical name for salt is sodium +chloride which is derived from the two names sodium and chlorine. + +Sodium and chlorine are both what we have learned to call elements. An +element being a substance which cannot be separated into substances +of different kinds. There are now known about seventy such elements. +All the substances around us are composed of these elements alone, or +chemically united in different compounds, or simply mixed together. +Most of them, however, are mixtures, not of separate elements, but of +compounds. The soil under our feet is a mixture of compounds. Water is +also a compound. Pure compounds very rarely occur naturally. Salt is +sometimes found almost pure; but generally is mixed with so many other +things that we have to take them out to get absolutely pure salt. For +practical every-day use it is unnecessary to purify the salt. + +Salt is found in large quantities in the sea water, in which it is +dissolved with some other substances. It is also found in salt beds, +formed by the drying up of old lakes that have no outlets; salt wells, +that yield strong brine; and salt mines, in which it is found in hard, +solid, transparent crystals, called rock salt. Rock salt is the purest +form in which salt is found and, to prepare it for market, it is merely +necessary to grind it or cut into blocks. The greatest deposit of salt +in the world is probably that at Wielizka in Poland, where there is a +bed 500 miles long, 20 miles wide, and 1,200 feet thick. Some of the +mines there are so extensive that it is said some of the miners spend +all their lives in them, never coming to the surface of the earth. + +A trip through these mines is interesting. In one of them can be seen +a church made entirely of salt. The salt supply of the United States +is obtained chiefly from the salt wells of Michigan and New York, the +Great Salt Lake in Utah, and the rock-salt mines of Louisiana and +Kansas. + +In the arts and manufactures, the most important uses of salt are +in glazing earthenware, in extracting metals from their ores, in +preserving meats and hides, in fertilizing arid soil, and also, as we +shall presently see, in the manufacture of soda. Of equal importance, +perhaps, is its use in food. Most people think it not only lends a +pleasant flavor, but is itself an important article of diet. It is +certain, that all people who can obtain it use salt in their food, and +where it is scarce, it is considered one of the greatest of luxuries. + +Soda is of interest to us, not so much on account of its use in +our households, as because it plays on extremely important part in +two industries that contribute greatly to our comfort, viz., the +manufacture of glass and soap. + +Soda is not found naturally in great abundance, as salt is, but is +generally made from other substances. Formerly it was made almost +entirely from the ashes of certain plants. One, known as the Salsoda +soda-plant, was formerly cultivated in Spain for the soda contained +in it, and the ashes, or Barilla, as they were called, were soaked in +water to dissolve out the soda. Now, however, the world’s soda supply +is produced from common salt by two processes, known from the names of +their inventors as the Leblanc and Solvay processes. + +~WHERE WE GET SODA~ + +In the Leblanc process the first step is to treat the salt, or sodium +chloride, with sulphuric acid. As a result of this, a compound of +sodium, sulphur, and oxygen, called sodium sulphate is formed, together +with another acid containing hydrogen and chlorine, and called +hydrochloric acid. This acid is driven off by boiling, and the sodium +sulphate is left. + +The next step in the process is to convert the sodium sulphate, or +“salt cake,” into soda, or, to give it its chemical name, sodium +carbonate. This change is brought about by mixing the salt cake with +limestone and coal and heating the mixture. Just what changes go on +when this is done, are not known, but the chief ones are probably the +following: the coal, which consists for the most part of an element +called carbon, takes the oxygen out of the sodium sulphate, and unites +with it to form carbonic acid gas, leaving a compound of sodium and +sulphur called sodium sulphide; this acts on the limestone, which is +composed of a metal, calcium, in combination with carbon and oxygen, +and causes the sulphur in the sodium sulphide to combine with the +calcium, forming calcium sulphide, while the sodium combines with the +carbon and oxygen and forms the desired compound, sodium carbonate. +After the heating, the resulting mass which contains calcium sulphide, +sodium carbonate, and some unburned coal, and is known as “black +ash,” is broken up and treated with water. This dissolves the sodium +carbonate, leaving the rest undissolved, and when part of the water is +evaporated crystals containing sodium carbonate and water are formed. +By heating these the water may be driven off, and the sodium carbonate +left behind as a white powder. + +The Solvay, or ammonia soda, process consists in forcing carbonic acid +gas through strong brine, to which a considerable quantity of ammonia +has been added. When this is done, crystals are formed in the brine, +which are composed of a compound of hydrogen, sodium, carbon, and +oxygen, and are called sodium bicarbonate. This substance, which is the +soda we sometimes use in baking bread, is decomposed by heating, into +water and sodium carbonate, the soda used for washing. + +The Leblanc process was formerly used almost altogether for making +soda; but in recent years the Solvay process has come into extensive +use, and it is said that now more than half the soda of the world is +made in this way. + + + + +Where Do All the Little Round Stones Come From? + + +The little round stones you are thinking of are really pebbles which +have been worn smooth and round by being rubbed against each other in +the water, through the action of the waves on a beach, or the running +water of brooks and streams. This sort of rock is called a water-formed +rock. Some of them have travelled many miles before they are found +side by side on the shore or in a large mass of what we would call +conglomerate rock. But whenever you see a round smooth rock or pebble +you may be quite sure that it was made round and smooth by the action +of water. + +You sometimes see large rocks made of small stones of various colors +and sizes. You can often find a large rock of this kind standing by +itself. If you examine it carefully, you will find it consists of an +immense number of small stones of different sizes and of a variety of +colors, all fastened together as though with cement. This kind of rock +is called conglomerate. We know two kinds of conglomerate rock, one, +quite common, in which the little stones are round and smooth, and +another, not seen so often, in which the stones are sharp. The latter +sort is sometimes called breccia, to distinguish it from the former, +which is called true pudding stone. + + + + +What Is Clay? + + +Clay is the result of the crumbling of a certain kind of rocks called +feldspars. When feldspar is exposed to the action of the weather, it +crumbles slowly at the surface and the little fragments combine with +a certain amount of water, forming clay. Pure clay is white and is +used in the manufacture of china and porcelain. The common clay that +we usually think of when we think of clay, is generally yellowish, +but there are many different colored clays. Most of these colors, +particularly those of red clay, yellow clay and blue clay, come from +the iron which is present in the clay. Clay which contains iron is +useful for making bricks. Bricks are made from clay by first softening +the clay and pressing it in molds, the size of a brick. When dried for +a time in the sun they are put into an oven and baked in great heat +and they become quite hard and generally red. Most of the clay from +which bricks are made turns red when baked, whether blue, yellow or +red, because the iron which is in the clay is generally turned red when +subjected to heat. + +For making porcelains it is desirable to use the kinds of clay which +contain nothing that melts when heated to a high degree. Clays which +contain substances which melt in strong heat are, therefore, not good +for making porcelains. There is a pure white clay called Kaolin which +is very excellent for this purpose. Clay out of which we make firebrick +for lining stoves and fireplaces is free from substances which melt. +Several kinds of clay are good for making paints. + + + + +Where Do School Slates Come From? + + +Slates such as are used in school and as roofing material are formed of +clay, which has been hardened under pressure and heat. When this occurs +it does so because a number of layers of clay, one on top of the other, +have at sometime been subjected to great heat and pressure within the +earth with the result that the clay is pressed into very thick layers +and changed in color by the heat and becomes hard. There are many kinds +of slate. Some of the slate, as found in slate mines, is used to make +roofs over buildings and for this purpose they are cut to shapes very +much like wooden shingles. They are easily broken, however, as slate is +very brittle. + +Slate is used in many other ways besides for roofs and school slates. +Sometimes it is made into slate pencils but, since paper has become +so cheap, comparatively few slate pencils are used in the school room +today. + + + + +What Causes Shadows? + + +Where anything through which rays of light cannot pass intercepts the +light rays coming from a luminous body, the light rays are turned back +in the direction from which they come and the part on the other side +of the object which intercepted the light goes into shade and a shadow +results. A shadow then is produced by cutting off one or more light +rays. We notice shadows when the sun is bright in the daytime and at +night when we walk along the streets lighted partly by street lamps. +The shadows we see in the daytime are caused by our cutting off and +throwing back some of the light rays which come from the sun. These are +not so dark as the shadows we see at night because the rays of light +from the sun are so bright and are reflected from so many other objects +to the side and in back of us. + +When, however, we are walking along a dimly lighted street and come to +a street lamp the shadows our bodies cause are quite black. The night +shadows are darker because the source of light is less intense and the +objects to the side of and in back of us (if we are walking toward the +light) do not reflect so much of the light rays as they do of the sun’s +rays in the daytime. + +[Illustration: DRIVING THE HOLLOW STEEL PILES TO BED ROCK.] + + + + +The Foundation of a Sky Scraper + + +How Hollow Steel Piles, Compressed and Concrete Are Employed to Make a +Foundation + +Rapidity of building construction is of primary importance in every +city of metropolitan size. When real estate is sold at the rate of +several hundred dollars a square foot it is self-evident that time is +indeed money. The delay of a few days in completing a structure may +deprive the owner of the chance of earning thousands in rental money. +Because of the excessive depth of an open caisson, the completion of +a foundation may be delayed for months. Hence the building may not +be completed until the renting period has passed and the owner must +wait an entire year before he can expect any financial return on his +investment. + +Because rapidity is so essential in city building construction the +method of first sinking an open pit to rock in providing a foundation +has been displaced to a large extent by a system in which heavy hollow +steel piles are employed in clusters to support a building. The hollow +piles are driven through quicksand to rock, cleaned out and ultimately +filled with concrete. + +~PILES ARE DRIVEN DOWN TO SOLID ROCK~ + +In this method of constructing foundations, which is illustrated, +hollow steel piles are driven in the well-known manner down to solid +rock. The steel pile sections vary in length from 20 feet to 22 feet, +and in diameter from 12 inches to 24 inches. If the ground is to be +penetrated to a depth greater than 22 feet, the sections of piling +are connected by means of a sleeve in such manner that a watertight +joint is formed. Under a pressure of 150 pounds to the square inch a +jet of compressed air is then employed to blow out the earth and water +contained within the shell. A spouting geyser of mud rising sometimes +to a height of 150 feet, and occasional large pieces of rock blown +up from a depth of 40 feet below the ground, bear testimony to the +terrific force of the air blast. + +[Illustration: THE PILES ARE ABOUT TWENTY-TWO FEET LONG. IF GREAT +DEPTHS ARE TO BE REACHED SECTIONS OF PILING ARE JOINED TOGETHER BY +MEANS OF A SLEEVE.] + +When the shell has been completely cleaned out by means of the blast +of compressed air, the exposed rock can be examined by lowering an +electric light. Steel sounding rods are employed to test the hardness +of the rock and to detect the difference between soft and hard bed +rock. After the piles in each pier have been cleaned out, they must +be cut off at absolutely the same height--sometimes a very difficult +task when there is little room. The oxy-acetylene torch is used for +the purpose, the intensely hot flame cutting off the steel almost like +butter at the exact elevation desired. + +[Illustration: CUTTING STEEL PILES WITH A HOT FLAME + +PILE BEING CUT TO PROPER LEVEL BY MEANS OF OXY-ACETYLENE TORCH. + +After the piles in each pier have been cleaned out they must be cut off +at exactly the same height--sometimes a very difficult task when there +is little room. The oxy-acetylene torch is used for the purpose, the +intensely hot flame cutting off the steel almost like butter.] + +[Illustration: A CLUSTER OF PILES, CLEANED OUT, FILLED WITH CONCRETE +AND CUT OFF FLUSH BY MEANS OF THE OXY-ACETYLENE FLAME.] + +~PILES ARE NEXT FILLED WITH CONCRETE~ + +The hollow shell is next filled with concrete reinforced by means of +long two-inch steel rods, sometimes fifty feet in length. On clusters +of these concrete-filled piles, the weight of the building is supported. + +That this method of constructing foundations is indeed rapid, the +story of the work at 145-147 West Twenty-eighth Street, New York City, +proves. Rock was located 38 feet below the curb. The material above +it was clay and water-bearing sand. Structural steel was due in three +weeks, but the completion of the cellar was still ten days off. The +steel pile foundation method offered the only solution of the problem. +Specifications were drawn which called for eighty-five 12-inch steel +piles, driven to rock, blown clean by compressed air, and filled with +concrete, reinforced with 2-inch rods. Despite various obstructions on +the ground (shoring of neighboring buildings and the like) the driving +was started on June 30th. The excavator was still taking out his runway +while the rear half of the lot was completely driven. After he had left +the ground a compressor was set up, and the first pipe was blown on +July 7th. Three days later all driving and cleaning had been completed. +During the following two days all the piles were filled and capped. In +a word, the entire foundation had been completed three days before the +expected arrival of the steel. + +[Illustration: CONCRETE PILES WHICH HAVE BEEN SUNK TO ROCK BOTTOM AND +IN WHICH TWO-INCH STEEL RODS HAVE BEEN INSERTED TO ACT AS REINFORCEMENT +FOR THE CONCRETE WHICH WILL EVENTUALLY BE POURED IN.] + +Such rapid work is not unusual with the steel foundation method. +On another contract, work was completed not in the three months +stipulated, but in exactly one month and a half, during which brief +time all the excavation had been done, including sheeting, shoring, +pile-driving, the mounting of concrete girders to carry the wall and +capping of the piles ready to receive the grillage. + +[Illustration: THE STEEL PILE IS EASILY FORCED EVEN THROUGH THE SOFT +UPPER LAYERS OF BED ROCK. SOMETIMES VERY LARGE PIECES ARE BLOWN UP INTO +THE AIR BY THE BLAST OF COMPRESSED AIR.] + +Sometimes difficulties are encountered which would prove all but +insurmountable and certainly hopelessly expensive with other methods. +Thus in carrying out the one contract, water was found 12 feet from the +curb. Two running streams had intersected at that point. The piles were +simply sunk through the stream to rock bottom without any difficulty. + +The excessive cost of open-pit work has sometimes made it impossible +to build twelve or fourteen-story buildings in many sections of the +city of New York. The steel pile has, however, made steel building +construction profitable. + +The carrying capacity of a steel pile is enormous. On a single 12-inch +steel pile one hundred tons can be safely maintained. Piers containing +sixteen piles have been used, and loadings up to 1300 tons are not +unusual. + +Naturally the question arises: Do the steel piles deteriorate in +time? The question has been answered over and over again by the piles +themselves. After a service of fifteen years the steel foundation +piles were removed from the site of a building which now stands at the +northwest corner of Wall and Nassau streets, in New York City. They +showed practically no deterioration. The oxidation on the outside was +almost negligible. + +[Illustration: BLOWING OUT MUD AND ROCK WITH COMPRESSED AIR + +CLEANING OUT A HOLLOW STEEL PILE BY MEANS OF COMPRESSED AIR A GEYSER OF +MUD ALWAYS APPEARS.] + +[Illustration: A DRIVEWAY ALONG THE TOP OF THE OLIVE BRIDGE DAM.] + + + + +The Story in a Glass of Water + + +How Does the Water Get into the Faucet? + +It is easy for you boys and girls who live in the city to run into the +kitchen or bathroom when you are thirsty and by a simple turn of the +faucet tap secure a glass of cool and refreshing water, but did you +ever stop to think how many men must constantly work and how great +and perfect arrangements must be made before it is possible to supply +a great city with water to drink, to bathe in, and for cooking and +washing? + +No one who has never had the experience of being in a town or city +from which the water supply has been cut off, for a day or a number of +days, can realize how necessary water is in our daily lives. We are so +used to having all the water we want at any time that we even complain +when in summer we are asked to drink water which is not iced. Drinking +ice-water is very much of a habit. In tropical countries where there is +no ice, people drink the water just as they find it, and if you were to +go there and drink the waters for a few days, you would soon find that +the water slakes your thirst even when quite warm, so it is not the ice +in the water that quenches your thirst, but the water itself, and the +ice-water is not good for you, as the doctor will tell you, because it +chills the stomach. + + +Where Does Our Drinking Water Come from? + +The best way to find out where the water in the faucet comes from is to +follow it back to its source. Let us see. Here we are in the kitchen +and you have just had a drink of water taken from the faucet above the +sink. The faucet, you will notice, is attached to a small pipe which +is fastened to the wall back of the sink. We look under the sink and +see that the pipe goes through a hole in the floor, so we reason that +the water must come from the cellar. Let us go down cellar and see. +Yes, here is the little pipe that comes down through the floor under +the sink and we follow it along the wall toward the front of the house, +and well, well, there it goes right out through the stone foundation of +the house. So we conclude that the water comes from somewhere outside +of the house, and that the little pipe we have been following is only +a means of getting it from the outside into the house. We now mark the +place in the wall where the pipe goes through and run around to the +front of the house to see where it comes out, but we don’t see it. It +must be buried in the ground, so we get a spade and pick and begin +to dig a hole in the ground, and pretty soon we find the little pipe +pointing straight out toward the street. We keep on digging the dirt +away, and thus open a little trench from the house to the middle of +the street and when we get there after a great deal of digging we find +our little pipe attached to a larger pipe which seems to run along the +ground in the middle of the street; so we are still in the dark as to +where the water comes from, excepting that so far as our own home is +concerned we know that it gets into the house through a little pipe +which is attached to a big pipe in the middle of the street. By this +time we know we have a big job on hand. + +[Illustration: HOW A BIG DAM IS BUILT + +BUILDING OLIVE BRIDGE DAM TO FORM THE ASHOKAN RESERVOIR. + +The great Ashokan reservoir is situated about fourteen miles west of +Kingston on the Hudson River. Its cost is $18,000,000, and it will hold +sufficient water to cover the whole of Manhattan Island to a depth of +twenty-eight feet. The water is impounded by the Olive Bridge dam, +which is built across Esopus Creek, and also by the Beaver Kill and +the Hurley dikes, which have been built across streams and gaps lying +between the hills which surround the reservoir.] + +[Illustration: THE OLIVE BRIDGE DAM, 4650 FEET LONG, 200 FEET HIGH. + +The dam is a masonry structure 190 feet in thickness at the base, and +23 feet thick at the top. The surface of the water when the reservoir +is full is 590 feet above tide level. The total length of the main dam +is 4560 feet, and the maximum depth of the water is 190 feet. The area +of the water surface is 12.8 square miles, and in preparing the bottom +it was necessary to remove seven villages, with a total population +of 2000. Forty miles of highway and ten bridges had to be built. In +the construction of the dam and dikes it was necessary to excavate +nearly 3,000,000 cubic yards of material, and 8,000,000 cubic yards of +embankment and nearly 1,000,000 cubic yards of masonry had to be put in +place. The maximum number of men employed on the job was 3000.] + +~HOW THE PIPES RUN THROUGH THE STREET~ + +We are pretty tired of digging by this time, so we call in all the boys +and girls in town to help us dig so that we may see where these pipes +come from, and we have a regular digging carnival. We follow the big +pipe along our own street until we come to the corner. Here we find +that our larger street pipe is connected with a still larger pipe, so +we think we had better follow the larger pipe. We keep on digging, +getting more of the boys and girls to help, and we follow that big pipe +right out to the edge of town where we see it runs into another stone +wall which you knew all the time was the reservoir, but concerning what +it was for you were perhaps never quite clear. + +Right near the place where the pipe goes in is a stairway which leads +up to the top of the wall, so the whole crowd of boys and girls climb +the steps and you are at the top of the reservoir; and there spread out +before you, you see a big lake surrounded with a stone wall and you see +where the water comes from--the reservoir--at least so you think. But +you are wrong. You really haven’t come anywhere near the source of the +supply. For soon as you walk around the broad top of the wall which +surrounds your reservoir, you meet a man who asks you what you want, +and you tell him that you have been finding out where the water in the +faucet came from, but having found out you thought you would go back +home. + +The man smiles at you, but, as he is good-natured and sees you are +really trying to find out where the water comes from, he tells you that +since you have gone to all the trouble of digging up the streets to +follow the pipes, you might as well learn all about it. + +He first tells you that the reservoir is not really the place where the +water comes from but only a tank, so to speak. He explains to you that +most of the faucets in the city are higher than the real source of the +water, which is out in the country miles away, and as water will not +run up hill, it is necessary to keep the city’s daily supply in some +place that is higher than the highest faucet in the city, so that it +will force its way into and fill to the very end all of the large pipes +in the streets and the small pipes which go into the houses, so that +the water will come out just as soon as you turn the faucet. + +Then he takes you over to a large building near the reservoir which +you have always called the water works, but never knew exactly what +it was for. He takes you into a large room where there is a lot of +nice-looking machinery working away steadily but quietly, and tells +you that these are the great pumps which lift the water from the great +pipes which bring it from far away in the country, into the reservoir +we have just seen, from which the water runs into and fills all of the +pipes into the city. + +He also tells you that in some cities it is impossible to find a place +to build a reservoir which is higher than the highest places in the +city. In such places, the pumps in the water works pump the water +direct into the city water pipes and force the water to the very end of +all the pipes and keep it there under pressure all the time. + +From the pumping station he takes you down stairs in the water works +and shows you the huge pipe which brings the water to the water works +from the country. It is quite the largest pipe you ever saw. You see it +is not really an iron pipe, but built of concrete, which is quite as +good. You will be surprised to have our friend, the water-works man, +tell you that three average-sized men could stand up on each other’s +shoulders inside the great pipe. + +[Illustration: HOW THE BIG PIPES ARE LAID THROUGH THE COUNTRY + +OLIVE BRIDGE DAM; ESOPUS CREEK FLOWING THROUGH TEMPORARY TUNNEL.] + +[Illustration: PLACING THE 9¹⁄₂ FOOT STEEL PIPES.] + +[Illustration: A HUGE UNDERGROUND RIVER + +The water is conducted from Ashokan reservoir as a huge, underground, +artificial river. The aqueduct is ninety-two miles in length from +Ashokan to the northern city line, and it should be explained that it +is built on a gentle grade, and that the water flows through this at +a slow and fairly constant speed. The aqueduct contains four distinct +types: the cut-and-cover, the grade tunnel, the pressure tunnel, +and the steel-pipe siphon. The cut-and-cover type, which is used on +fifty-five miles of the aqueduct, is of a horseshoe shape and measures +17 feet high by 17 feet 6 inches wide, inside measurements. It is +built of concrete, and on completion it is covered in with an earth +embankment. This type is used wherever the nature of the ground and +the elevation allow. Where the aqueduct intersects hills or mountains, +it is driven through them in tunnel at the standard grade. There are +twenty-four of these tunnels, aggregating fourteen miles in length. +They are horseshoe in shape, 17 feet high by 16 feet 4 inches wide, and +they are lined with concrete. When the line of the aqueduct encountered +deep and broad valleys, they were crossed by two methods: if suitable +rock were present, circular tunnels were driven deep within this rock +and lined with concrete. There are seven of these pressure tunnels +of a total length of seventeen miles. Their internal diameter is 14 +feet, and at each end of each tunnel a vertical shaft connects the +tunnel with the grade tunnel above. If the bottom of the valley did +not offer suitable rock for a rock tunnel, or if there were other +prohibitive reasons, steel siphons were used. These are 9 feet and 11 +feet in diameter. They are lined with two inches of cement mortar and +are imbedded in concrete and covered with an earth embankment. There +are fourteen of these pipe siphons of a total length of six miles. At +present one pipe suffices to carry the water. Ultimately three will be +required for each siphon.] + +Our water-works man sees how earnest you are in seeing just where the +water comes from, so he proposes that we go find out. We go outside and +there is an automobile all ready to go and we jump in and the machine +starts off along quite one of the nicest roads you were ever on. Soon +you exclaim, “Why, this is the aqueduct road,” and so it is. The great +pipe through which the water comes to the city is an aqueduct and they +have built the road right over the place where the aqueduct runs. Away +we go as fast as the car can carry us, sometimes ten, or twenty or +perhaps fifty miles, according to what city you are in. The city goes +as far as it must to find a supply of pure water and plenty of it and +spends millions upon millions of dollars to make its supply of water +good and certain. Occasionally we come to a little stone house along +the way where we can go down and see the sides of the great stone pipe. +After a while, however, we find our aqueduct road comes to an abrupt +stop before another great stone wall. It is the great dam which has +been built out there in the country to form one end of a great tank +that catches and holds the waters from the creeks and rivers that flow +into it. Usually the dam is built up right across a river. They simply +build the dam strong enough to stop the river from going any further. +Then, of course, the water piles up on the other side of the dam and +occasionally this tank, which is simply another huge reservoir, gets so +full that the water flows over. It does not really overflow the top of +the dam, because underneath the top the engineers have left openings +here and there for the water to get through. If it were not for these +loopholes, so to speak, the great wall of water within the reservoir, +piled against the dam, would break down the wall no matter how well +built, by the great pressure it exerts. + +[Illustration: THROUGH THIS CHAMBER THE FLOW OF WATER TO THE AQUEDUCT +IS REGULATED.] + +~THE REAL SOURCE OF THE WATER~ + +We are now near to the real source of the water. We take a trip around +the top of the great reservoir. Around at the other end we find what +looks like a river, excepting that there isn’t any current to speak of. +It is a river, but a much deeper one than it would have been but for +the dam which has been built across it, and originally its surface was +quite far down in a valley. Sometimes man makes his water dam at one +end of a lake, which has been formed by streams flowing into a valley +which has no opening for the water to run out of. In these cases the +lake will be high up in the hills and man simply builds his dam at one +end, lets the end of his aqueduct into the bottom of the lake and the +water flows. In other cases he picks out a valley where there is no +lake at all, builds his dam and then drains the water which he finds in +small lakes higher up in the hills into the one big valley and makes a +very large lake. But the water in the lakes comes originally from the +creeks, rivers or springs which run into it, and so we will follow our +original river back into the hills. Here and there along its course we +find a little stream flowing into our river and, as we go up higher and +higher into the hills, we find our river getting smaller and smaller. +Now it is only a creek and, if we go far enough, we find its source but +the tiniest kind of a tinkling brook with the water dripping almost +noiselessly between the rocks as it makes its path down the side of +the hill. There is the source of the water in the glass you have just +enjoyed. + +[Illustration: DIGGING A HOLE UNDER A RIVER + +DIAMOND DRILL BORING A HORIZONTAL HOLE 1100 FEET BELOW THE HUDSON +RIVER.] + +[Illustration: HUDSON RIVER SIPHON, 1100 FEET BELOW THE RIVER. + +Of the many siphons constructed, by far the most interesting and +difficult is that which has been completed beneath the Hudson River. +The preliminary borings made from scows in the river showed that great +depths would have to be reached before rock sufficiently solid and +free from seams was encountered to withstand the enormous hydraulic +pressure of the water in the tunnel. After failing to reach rock by the +scow drills, two series of inclined borings were made from each shore, +one pair intercepting at about 900 feet depth and the other at about +1500 feet. Both showed satisfactory rock, and accordingly a shaft was +sunk on each shore, to a depth of approximately 1100 feet, and then a +horizontal tunnel was driven connecting the two. It is of interest to +note that because of the enormous head, which must be measured from the +flow line far above the river surface, the pressure in the horizontal +tunnel reaches over forty tons per square foot.] + +[Illustration: THE HIGHEST BUILDING IN THE WORLD UPSIDE DOWN + + SHAFT 752′-0 DEEP + + WOOLWORTH BUILDING 750′ 0″ HIGH + +This picture shows the depth to which the pipes which carry the water +through the city must sometimes be sunk in order that it will be +certain to remain in place. To illustrate this in connection with the +depth of the water tunnel in one place in the city of New York, our +artist has taken the liberty of turning the Woolworth Building upside +down. Even this building, which is the tallest business building in the +world, and is 792 feet high, would not penetrate the water tunnel, at +the point shown, which is at the Clinton Street shaft at the west bank +of the East River.] + + + + +What is Carbonic Acid? + + +It was formerly called fixed air, and is a gaseous compound of +carbon and oxygen. It is procured by the processes of combustion and +respiration, and hence is always present in the air, though in minute +quantity. Plants live upon it and absorb it into their tissues; they +abstract and assimilate its carbon, and return its oxygen to the +atmosphere in a pure condition. It is also present in spring water, +and often in quantities, so that it sparkles and effervesces; it is +also produced during the processes of putrefaction, fermentation, and +slow decay of animal and vegetable substances in presence of air. It +is largely employed by the manufacturers of aerated bread and aerated +waters. Under a pressure of about 600 pounds it liquefies, and when +allowed to escape through a small jet it rapidly evaporates and causes +intense cold, so much so as to become frozen. It does not support +burning. The gas derived from it, carbon dioxide, is invisible, and +is heavier than air by one half, and has a pungent odor and slightly +acid taste. In a pure state the gas cannot be respired, as it supports +neither respiration nor combustion. When the portion in the atmosphere +is increased to a considerable extent, as happens sometimes, it +endangers life. The familiar “rising” of bread is brought about by +carbonic acid gas escaping through and permeating the dough, making +it light and porous. In this form it is known as yeast or as baking +powder. We see its uses also in the chemical fire-engine. + +In some parts of the world large quantities of carbonic acid gas are +constantly issuing from openings of the earth’s surface. Two such +places are the famous Poison Valley of Java, and the Grotto del Cane, +near Naples, in Italy. The former is a small valley about a half a mile +around and about thirty-five feet deep, in which the air is so loaded +with carbonic acid gas that animals entering it are killed in a few +minutes. Even birds that fly over the valley are overcome if they do +not rise high above it. The Grotto del Cane, or Grotto of the Dog, is +a small cavern in the crater of a volcano. A stream of carbonic acid +gas flows constantly into the grotto, but the level of the gas does not +reach the height of a man’s mouth. When the same air is breathed over +and over again, the quantity of carbonic acid in it is increased so +much, that it may become as deadly as the air in the Poison Valley. + +Two other gases that may generally be found in air are ozone and +ammonia. The first is merely a form of oxygen that is produced by the +passage of lightning through the air. After severe thunderstorms, it is +said to be present, sometimes, in sufficient proportion to give to the +air a slightly pungent odor. It is more active chemically than is the +ordinary form of oxygen, and consequently has a stimulating effect upon +animals. + +Ammonia, or hartshorn, as it is sometimes called, from the fact that +it was formerly obtained by distilling the horns of harts, or deer, is +almost always present in the air in small quantities. It is produced +chiefly by the decay of animal and vegetable matter, especially the +former. Though present in the air in very small quantities, it is of +much value to the plant world, because it contains nitrogen in a form +in which it can be readily absorbed by plants. All plants contain some +nitrogen, which is essential to their growth, but the greater part of +the nitrogen in the air is not in such form that it can be absorbed +by them. They must obtain their supply from the soil, which usually +contains some nitrogen in a form that may be taken up by plants, and +from the ammonia in the air. The latter is not taken directly out of +the air by the plants, but the rains falling through the air absorb the +ammonia and carry it to the soil, from which it is taken up into the +plants by their roots. + +~VARIOUS GASES FOUND IN AIR~ + +Besides the gases that have been mentioned, there is present in the +air, at all times, a small quantity of water-vapor, which is, in many +ways as important to mankind as is the oxygen itself. The quantity +of water in the air is not always the same. As a rule, the quantity +is greater in warm air than in cold, and is less over land than over +water. Frequently the air feels damp in cold weather, and dry in hot +weather, and it is natural to suppose that there is more vapor in the +air on the damp day than on the dry one. This, however, is not always +true. There is usually more moisture in the air on a warm summer day +than on a cold day in winter, though the winter day may seem much more +moist. You will be able to understand why this is so by comparing the +air to a sponge. If we fill a sponge with water, and squeeze it gently, +a little water will be forced out of it. If we then remove the pressure +on the sponge. When the air cools, will appear dry on the surface, but +there will still be water in it, and on being squeezed harder than +before it will again become moist on the surface and more water will be +forced out of it. Now cold has an effect upon moisture-laden air very +much like that of pressure on the sponge. When the air cools, some of +the moisture is forced out of it, and the air seems damp. When it warms +again, the air seems dry, though there is still water-vapor in it. It +seems dry because it can absorb more water-vapor, just as the sponge +seems dry after you cease to squeeze it, though it still contains +water. From this we see that the air does not always seem moist when +there is much water-vapor in it, nor dry when there is only a little. +It feels moist when there is as much water-vapor present as it can +hold, and dry when it can held more than it already has. And we also +see that in hot weather the air can hold much more moisture than it can +in cold weather, so that whether the air feels dry or moist, there is +generally much more water-vapor in it in hot weather than in cold. + +It is easy to see that, over water, the air naturally takes up more +moisture than over land, because there is so much more water there to +be transformed into vapor. Over the surface of seas, lakes and rivers, +water is continually being converted into vapor by the process of +evaporation, and this vapor is absorbed by the air. + +Let us now consider the solid particles floating in the air, the dust +that is seen dancing in the path of a sunbeam. Whenever we examine the +air, these small particles are found, even on the tops of mountains, +and at points so high above the earth that they have been reached only +by balloons. Of course, there is very much less dust high above the +earth than near the surface, where the winds are constantly stirring +up the loose soil, and throwing into the air small particles of every +kind. In cities, where factory chimneys are continually pouring out +clouds of smoke, and the people and vehicles are constantly disturbing +the dust of the streets, the air always contains more dust than does +the air of the country. + +In order that we may breathe air, the oxygen in it has been mixed with +four times as much nitrogen and argon, which must be inhaled with the +oxygen, though they have no more effect on the body than the water +you take with a strong medicine to weaken it. The oxygen, however, +has a very important effect upon the body, and if we compare the air +we exhale with that we inhale we find considerably less oxygen in +the former than in the latter. In place of the oxygen, the air has +received carbonic acid gas. It may seem very strange to say that there +is burning going on in the body, but that is very nearly what takes +place. The chief difference from coal-burning is that in the body the +process goes on so slowly that it does not make the body very hot; +but when we set fire to coal, the process is much more rapid, and a +large amount of heat is produced in a short time, so that the coal +becomes very hot. The products of breathing and of coal-burning are the +same, carbonic acid gas being the chief one. When coal is burned it +disappears, together with some of the oxygen of the air, and in their +stead we have carbonic acid gas. When a breath is taken some of the +material of the body disappears, as does some of the oxygen of the air, +and in place of them carbonic acid gas is found. If we could weigh the +coal burned and the oxygen that disappears in the burning of it, and +could then weigh the carbonic acid gas that is produced in the burning, +we should find that the latter weighs just as much as the coal and the +oxygen together. So, too, if we could weigh the oxygen that disappears +from the air we breathe, and also find the weight of the material taken +from our bodies by breathing, we should find that the two together +weigh just as much as the carbonic acid gas given off in our breath. In +neither case is anything absolutely destroyed; the substances resulting +from the change weigh just as much as those that took part in it. + +Having learned that a quantity of oxygen disappears every time we +take a breath, every time we build a fire, it would seem that in the +thousands of years during which men and animals have been living on the +earth, all the oxygen would have been exhausted and nothing left in +its place but carbonic acid gas. That, however, is impossible, as the +carbonic acid gas is used up almost as fast as it is produced and the +oxygen is returned to the air in its stead. + +~HOW PLANTS EAT CARBONIC ACID~ + +All trees and plants, from the great redwood trees of California to the +smallest flowers that dot the fields, need carbonic acid gas to keep +them alive and to make them grow. Their leaves have the power when the +sun shines on them to take up carbonic acid from the air and to return +oxygen in exchange. In this way you see that the balance is kept just +as it should be. The oxygen needed by animals of all kinds is furnished +by the plants, and the carbonic acid required by plants is thrown off +in the breath of animals. + + + + +Is It a Fact that the Sun Revolves On Its Axis? + + +It is a proved fact that the sun revolves on its axis. All parts of its +surface, however, do not rotate with the same velocity. The rotation of +the sun differs from that of the earth in this respect. + +This constitutes the visible proof that the physical state of the sun +is different from the earth’s, although they are composed of similar +chemical elements. + +The earth, being covered with a solid crust, and being also, as recent +investigation demonstrates, as rigid as steel throughout its entire +globe, rotates with one and the same angular velocity from the equator +to the poles. + +If you stood on the earth’s equator you would be carried by its daily +rotation round a circle about 25,000 miles in circumference. If you +stood within a yard of the North or South Pole you would be carried, by +the same motion, round a circle not quite 19 feet in circumference. And +yet it would require precisely the same time, viz., twenty-four hours, +to describe the 19-foot circle as the 25,000-mile one. + + + + +What Is the Most Usefully Valuable Metal? + + +If you were guessing you would naturally say that gold is, of course, +the most valuable of the metals. But you would be wrong. The proper +answer to this is iron. We do not mean the pound for pound value, for +you could get much more money for a pound of gold than for a pound +of iron, but we mean in useful value--iron is in that sense the most +valuable metal known to man. This is so because iron is of great +service to man in so many different ways, and it is very well that +there is so great a quantity of it for man’s use. + +[Illustration: WHERE DOES TOBACCO COME FROM? + +GROWING TOBACCO UNDER CHEESECLOTH.] + + + + +The Story in a Pipe and Cigar[6] + + [6] Copyright by Tobacco Leaf Publishing Co. + + +Where Did the Name Tobacco Originate? + +It is now generally agreed that the word tobacco is derived from +“tobago,” which was an Indian pipe. The tobago was Y-shaped, and +usually consisted of a hollow, forked reed, the two prongs of which +were fitted into the nostrils, the smoke being drawn from tobacco +placed in the end of the stem. The island of Tobago, contrary to the +belief of many, did not furnish the name for tobacco, but on the other +hand, it was given that name by Columbus, owing to its resemblance in +shape to the Indian pipe. + + +How Was Tobacco Discovered? + +While tobacco is now found growing in all inhabited countries, it is a +native of the Americas and adjacent islands. Its discovery by civilized +man was coincident with the discovery of this continent by Christopher +Columbus in 1492. Columbus and his adventurous sailors found the +native Indians using the weed on the explorer’s first visit to the new +world. Investigation has established that the plant was first used +as a religious rite and gradually became a social habit among the +natives. Columbus and his Castilian successors carried the weed to +Spain. Sir Walter Raleigh took it to England, Jean Nicot, whose name +is immortalized in nicotine, introduced it to the French; adventurous +traders brought the seed to Turkey and Syria, and Spanish argosies +carried it westward from Mexico to the Philippines and thence to China +and Japan. Thus within two centuries after its discovery tobacco was +being cultivated in nearly every country and was being used by every +race of men. + + +Where Does Tobacco Grow? + +While tobacco is a native of the Americas, it is a fact that it will +grow after a fashion almost anywhere. Milton Whitney, Chief of the +Division of Soils, United States Department of Agriculture, in his +bulletin on tobacco soils says tobacco can be grown in nearly all +parts of the country even where wheat and corn cannot economically +be grown. The plant readily adapts itself to the great range of +climatic conditions, will grow on nearly all kinds of soil and has +a comparatively short season of growth. But while it can be so +universally grown, the flavor and quality of the leaf are greatly +influenced by the conditions of climate and soil. The industry has +been very highly specialized and there is only demand now for tobacco +possessing certain qualities adapted to certain specific purposes.... +It is a curious and interesting fact that tobacco suitable for our +domestic cigars, is raised in Sumatra, Cuba and Florida, and then +passing over our middle tobacco States the cigar type is found again +in Massachusetts, Connecticut, Pennsylvania, Ohio and Wisconsin.... +It is surprising to find so little difference in the meteorological +record for these several places during the crop season. There does not +seem to be sufficient difference to explain the distribution of the +different classes of tobacco, and yet this distribution is probably +due mainly to climatic conditions.... The plant is far more sensitive +to these meteorological conditions than are our instruments. Even in +such a famous tobacco region as Cuba, tobacco of good quality cannot +be grown in the immediate vicinity of the ocean or in certain parts +of the island that would otherwise be considered good tobacco lands. +This has been experienced also in Sumatra and in our own country, but +the influences are too subtle to be detected by our meteorological +instruments.... Under good climatic conditions, the class and type +of tobacco depend upon the character of the soil, especially on the +physical character of the soil upon which it is grown, while the grade +is dependent largely upon the cultivation and curing of the crop. +Different types of tobacco are grown on widely different soils all the +way from the coarse sandy lands of the Pine Barrens, to the heavy, +clay, limestone, corn and wheat lands. The best soil for one kind of +tobacco, therefore, may be almost worthless for the staple agricultural +crops, while the best for another type of tobacco may be the richest +and most productive soil of any that we have. + +~WHERE HAVANA TOBACCO IS GROWN~ + +Havana tobacco, which means all tobacco grown on the island of Cuba, +possesses peculiar qualities which make it the finest tobacco in the +world for cigar purposes. The island produces from 350,000 to 500,000 +bales annually, of which 150,000 to 250,000 bales come to the United +States for use in American cigar factories. The best quality of the +Cuban tobacco comes largely from the Vuelta Abajo section, although +some very choice tobaccos are raised also in the Partidos section. +Remedios tobaccos are more heavily bodied than others and are used +almost exclusively for blending with our domestic tobaccos. While there +are innumerable sub-classifications, such as Semi-Vueltas, Remates, +Tumbadero, etc., the three general divisions named above, Vuelta +Abajo, Partidos and Remedios, embrace the entire island. If a fourth +general classification were to be added, it would be Semi-Vueltas. +The Vuelta Abajo is grown in the Province of Pinar del Rio, located +at the western end of the island. It is raised practically throughout +the entire province. Semi-Vueltas are also grown in Pinar del Rio, but +the trade draws a line between them and the genuine Vueltas. Partidos +tobacco, which is grown principally in the Province of Havana, differs +from the Vuelta Abajo in that it is of a much lighter quality. The +Partidos country is famous for its production of fine light glossy +wrappers. Tobacco from the foregoing sections is used principally in +the manufacture of clear Havana cigars. Some of the heavier Vueltas, +however, are also used for seed and Havana cigar purposes. Remedios, +otherwise known as Vuelta-Arriba, is grown in the Province of Santa +Clara, located in the center of the island. This tobacco is taken +almost entirely by the United States and Europe and is used here for +filler purposes, principally in seed and Havana cigars. Its general +characteristics are a high flavor and rather heavy body, which make it +especially suitable for blending with our domestic tobaccos. Havana +tobacco is packed and marketed in bales. + + +Preparing the Seed Beds. + +The first step is the preparation of the seed beds. For these beds +low, rich, hardwood lands are selected. The trees are cut down and the +wood split, converted into cord wood and piled up to dry. About the +middle of January this wood is stacked up on skid poles and ignited. +The ground is thus cleared by burning, the fires being moved from spot +to spot until a sufficient area is cleared. By this process all grass, +weeds, brush and insects are eradicated. The ground is then dug up with +hoes and cleared off and a perfect seed bed is made. + +The tobacco seed is first mixed with dry ashes in the proportion of +about a tablespoonful of seed to a gallon of the ashes, and about this +quantity is sowed over a square rod of land. This amount is calculated +to supply plants enough for one acre of ground, but the farmers usually +double the planting as a precaution against emergencies. After the seed +beds are sowed they are covered over with cheesecloth as a means of +protection, and they are carefully weeded and watered until the leaves +have attained a length of about four inches. They are then ready for +transplanting, which operation begins about the middle of April. + + +Fertilization. + +In the meantime, the tobacco-growing areas have been prepared by +plowing and fertilizing. The matter of fertilization has been the +subject of much study and many experiments, and it has been definitely +established that cow manure is one of the best for this purpose. +This natural fertilizer is distributed on the fields at the rate of +ten to twenty two-horse loads to each acre. In addition to this from +two hundred to three hundred pounds of carbonate of potash, and from +two thousand to three thousand pounds of bright cottonseed meal are +employed. The total cost of this fertilizer amounts to about $120 per +acre. + + +Planting. + +After the fertilizer is well plowed into the land the ground is laid +off into ridges about four feet apart, made by throwing two one-horse +furrows together. These ridges are about two feet in width and are +flattened on the top so as to make a level bed for the young plant. The +farmer then measures off and marks these rows at intervals of 16 to 18 +inches. At each mark he makes a small hole, and after pouring in a pint +of water the plant is carefully set. Machine planters are used for this +purpose to a limited extent. + + +Care of the Growing Crop. + +The growers usually calculate on finishing their planting about the +first of June. The young plants are then closely watched and are hoed +and cultivated at least once a week. They are also supplied with +sufficient water to keep them alive and growing. At this stage of the +proceedings, the planter begins to look out for worms. The butter worm +is one of his greatest enemies. This is a small green moth that lays +its eggs in the bud of the plant and turns into a worm two days later. +To stop the ravages of this insect, it is customary to use a mixture +composed of some insecticide mixed with corn meal. A small pinch of +this mixture is inserted at regular intervals in the bud of each plant +until the plant is nearly grown. + +When the tobacco is about three feet high, all such leaves as were on +the plant when it was first set out are picked off and thrown away. +About this time the crop is usually threatened by another enemy known +as the horn worm. This is a large, mouse-colored moth, which swarms +over the field about sun-down, and deposits green eggs about the size +of a very small bird shot, on the back sides of the leaves. This is a +very ravenous insect and unless carefully watched it will devour every +leaf of tobacco, leaving nothing but the stalks standing. It is removed +by picking off and by insecticides. + +[Illustration: A FIELD OF FINE HAVANA.] + + +Harvesting. + +About sixty to ninety days after setting, the bottom leaves on the +plant are ripe and the grower is able to remove from three to four +on each stalk. This is called priming. The primer detaches each leaf +carefully and places it face down in his left hand, inspecting it at +the same time to see that no worms are carried to the barns. Upon +accumulating a handful, he places them in baskets that are lined with +burlap to prevent injury to the leaf, and the filled baskets are either +carried or hauled to the barns. + +About this time the plants have begun to bud out at the top, and +this bud, with a few small leaves around it, is broken off. This +process is called topping, and is done for the purpose of confining +the development of the plant to the leaves below. After topping, the +priming of the tobacco is continued for about three weeks, and until +all the upper leaves of marketable value have been harvested. In the +meantime, the suckering has to be looked after, which is the removing +of the small branches that have a tendency to grow out of the main +stalk of the plant. + +In the barns the leaves are placed on long tables, behind which stand +the stringers. They string the leaves, each separately, on strong +cotton twine, about thirty leaves to a string, spaced about an inch +apart. If this is not done carefully and accurately, several leaves may +become bunched together and the cure will thereby be impaired. It is +attention to this detail which prevents the defect known as pole-sweat. +These strings are tied at either end to a tobacco lath, and the lath is +hung upon two poles. These poles are placed in courses in the barn, at +spaces of two feet, one above the other. + +[Illustration: A MODERN CUBAN TOBACCO PLANTATION.] + +~HOW TOBACCO IS CURED~ + +Here the tobacco undergoes its preliminary, or barn cure, and during +this period the grower is constantly on the anxious seat, having to +open and close his curing houses according to the changes in the +weather, and to look closely after the ventilation of his crop in order +to avoid the development of stem rot and other afflictions with which +the tobacco is threatened at this stage of the proceedings. + +[Illustration: A STAND OF TOBACCO IN EACH HAND.] + + +Bulk Sweating. + +In due course of time the laths are taken down, the strings removed and +the leaves are formed into hands and tied with a string. The tobacco is +then packed temporarily in cases and delivered at the fermenting house, +where it is put into what is known as the bulk sweat. This consists +of uniform piles of tobacco covered over with blankets, and which are +frequently “turned” in order that they shall cure evenly and not become +too dark in color. From the bulk sweat the tobacco goes to the sorting +tables, where it is divided into numerous grades of length and color. +It is then turned over to the packers, who form it into bales. + + +How is Tobacco Cultivated? + +As the young plants spring up and begin to grow, they are thinned out, +watered and cared for until along in October or November, and as soon +as the weather becomes settled for the season, the little seedlings +are transplanted into the field. Some growers use shade, but most of +the tobacco is grown in the open. The plants are placed in rows, very +much as corn is planted, only farther apart. The plants are carefully +protected from weeds and insects, and in December the early tobacco is +ready to be harvested. Here the mode of procedure differs according +to the discretion of the grower. The plan universally in vogue until +recent years was to cut the plant down at the base of the stalk. +Lately, however, the more scientific growers harvest their tobacco +gradually, picking it leaf by leaf, according as they ripen and mature. +The tobacco is then allowed to lie in the field until the leaves are +wilted. The stalks (or stems, according to the method followed) are +then strung on _cujes_ or poles, so that the plants hang with the tips +down. The tobacco is then allowed to hang in the sun until it is dry +and later carried into the barns, where the poles are suspended in +tiers until the barn is full. Tobacco barns everywhere are constructed +with movable, or rather, adjustable, side and end walls which permit of +a constant adjustment of the ventilation. While hanging in the barn the +tobacco undergoes its preliminary cure and changes in color from the +green of the growing plant to a yellowish brown. The climatic changes +have to be carefully studied during this process. If the weather is +extremely dry it is customary to keep the barns closed in the daytime +and to open the ventilators at night. It is generally desirable to +keep the tobacco fairly dry while it is undergoing the barn cure. After +a few weeks, and when the hanging tobacco has reached the proper stage +of maturity, a period of damp weather is looked for so that the dry +leaves may be rehandled without injury. When the desired shower comes +along the tobacco is stripped off the poles and placed in _pilon_--that +is, in heaps, or piles, on the floors of the barns and warehouses, each +pile being covered with blankets. Here, being in a compact mass, it +undergoes the _calentura_, or fever, by which it is pretty thoroughly +cured, the color changing to a deeper brown. After about two weeks in +the piles it is sorted, tied into small bundles or carrots, and these +in turn are packed in bales. After being baled the tobacco, if allowed +to remain undisturbed, undergoes a third cure, by which it is greatly +improved in quality. It is then ready for the factory. + +[Illustration: A TOBACCO BARN.] + + +The Shade-growing Method. + +The shade-growing method is one of the institutions of modern tobacco +cultivation. The principle is this: The sun, shining on the tobacco +plants, draws the nutrition from the earth, and the plant ripens +quickly, the leaves having a tendency to be heavy-bodied and not very +large. To defeat these results and produce large, thin, silky leaves +for cigar-wrapper purposes, the grower sometimes covers his field with +a tent of cheesecloth or with a lattice-work of lathing which protects +the growing tobacco from the direct rays of the sun. Thus the ripening +process is slower, causing the leaves to grow larger and thinner and +less gummy; and being thinner and less gummy, they are of a lighter +color when finally cured. This method is employed by some growers in +cigar-leaf districts, such as Cuba, Florida and Connecticut. + +[Illustration: TAKING TOBACCO FROM BALES] + + +How Are Cigars Made? + +While many labor-saving devices have been introduced in all branches +of tobacco manufacture, it is a curious fact that in the production +of the best grade of cigars, namely, the clear Havana, the work is +done entirely by hand. In fact, it may be said that in the process of +manufacturing fine cigars exactly the same principles are followed +as those of two centuries ago. There has been much improvement in +the artisanship of the worker, of course, but no rudimentary change +in method. In the manufacture of snuff, chewing and pipe tobacco, +cigarettes and all-tobacco cigarettes, machinery plays an important +part; and mechanical devices are also used extensively in the +production of five-cent cigars and in the still higher priced grades +of part-domestic cigars, such as the seed and Havana. Some of these +appliances are almost human in their ingenuity. But in fashioning the +tobacco of Cuba into cigars that are perfect in shape, in formation +and in all the qualities that go to make a good cigar, there is no +substitute for the human hand. + +Upon opening a bale of tobacco the workman takes each carrot out +separately, shakes it gently to separate the leaves, and then moistens +it, either by dipping it into a tub of water from which it is quickly +removed and shaken to throw off the surplus water or else by spraying +it with a blower. It is left in this condition over night, so that the +leaves may absorb the moisture and become uniformly damp and pliable. + +The tobacco is then turned over to the strippers, who remove the midrib +from each leaf, at the same time separating the wrapper from the +filler. From this point on the treatment of the wrappers and fillers is +different. + +The half leaves suitable for fillers are spread out and placed one +on top of the other, making what are called books. These books are +placed side by side, closely together, on a board, and a similar board +is placed on top of the tobacco to hold it in position. Later, it is +packed into barrels, the tops of which are covered with burlap, and +there it undergoes a fermentation. It is usually allowed to remain in +this condition for ten days or two weeks, when it is rehandled and +inspected, and if found to be in the right condition, it is placed on +racks, where it remains until it is in just the proper state of dryness +to be ready for working. + +~THE GREAT CARE NECESSARY IN SELECTION~ + +The wrapper leaves, after leaving the hands of the stripper, are taken +by the wrapper selector, who sits, usually, at a barrel, and spreads +out each leaf, one on top of the other, over the edge of the barrel, +assorting them as to size, color, etc., into several different piles or +books. Each of these piles is divided into packs of twenty-five each, +and each lot of twenty-five is folded over into what is called a “pad” +and tied with a stem. It is in this form that they go to the cigarmaker. + +Every morning the stock is distributed among the cigarmakers. Each +workman is given enough tobacco to make a certain number of cigars, +and when his work is finished he must return either the full number of +cigars or the equivalent in unused leaves. + +The tools of the cigarmaker consist merely of a square piece of +hardwood board, a knife and a pot of gum tragacanth. He sits at a +table upon which rests the board, and at which there is also a gauge +on which the different lengths are indicated. Fastened to the front +of each table is a sack or pocket of burlap into which the cuttings +that accumulate on the table are brushed. The operator deftly cuts his +wrapper from the leaf, fashions the filler into proper form and size +in the palm of his hand (this is known as the “bunch”) and rolls the +tobacco into cigar form, In winding the wrapper around the “bunch” the +operator begins at the “lighting end” of the cigar, called the “tuck,” +and finishes at the end that goes into the mouth, which is called the +“head.” A bit of gum tragacanth is used to fasten the leaf securely at +the “head.” The cigar is then held to the gauge and is trimmed smoothly +off to the proper length by a stroke of the knife at the “tuck.” The +cigars are taken up in bundles of fifty each. They next pass into +the hands of the selectors, who separate them into different piles, +according to the color of the wrappers, and who also reject any cigars +that may be of faulty construction. Broken wrappers, bad colors or any +other defects are sufficient to cause the rejection of a cigar. The +rejected cigars are known as _resagos_ (“throwouts”) or _secundos_. + +From the selectors the cigars go to the packers, whose duty it is to +place them in the boxes, and to see that the colors in each box are +uniform, marking the temporary color classification on each box in lead +pencil. After being packed, the filled boxes are put into a press and +so left for twelve hours or until the cigars conform somewhat to the +shape of the box which contains them. On being removed from the press, +if to be banded, the cigars are carefully removed in layers from the +box, the bands affixed, and the cigars replaced. The goods are then +placed in an air-tight vault to await shipment. + +When the cigarmaker ties up his bundle of fifty cigars, he attaches to +it a slip of paper upon which is marked his number. This enables the +manufacturer to keep an accurate account of the number of cigars made +by each workman and also to place the responsibility for any defects in +the workmanship. Cigarmakers are paid by the piece, the scale of wages +ranging from $16 to $100 per thousand. In nearly every factory there +may be found advanced apprentices or old men working at the rate of +$14 per thousand and also there may be found skilled artisans making +exceptionally large odd sizes at more than $100 per thousand, but these +are not generally considered in the regulation scale of prices. In +averages, the workmen earn about $18 a week and make about 150 cigars a +day. + + +Just a Few Figures About Tobacco. + +The internal revenue from tobacco for one year would build fourteen +battleships of the first-class; or it would pay the salary of the +President of the United States for nearly a thousand years. It would +pay the interest on the public debt for three years, and there would be +enough left over to add a dollar to the account of every savings bank +depositor in the United States. + +The money spent by smokers for cigars only, _not counting_ cigarettes, +smoking and chewing tobacco and snuff would more than pay for the +building of the Panama Canal, besides taking care of the $50,000,000 +paid to the new French Canal Co., and the Republic of Panama for +property and franchises. And in addition to this it would cover the +cost of fortifying the Canal. + +Or it would build a fleet of thirty-five trans-Atlantic liners, each +exactly like the lost _Titanic_, coal them, provision them and keep +them running between New York and Liverpool with a full complement of +passengers and crew, almost indefinitely. + +There are 21,718,448 cigars burned up in the United States every +twenty-four hours; and 904,935 every hour; and 15,082 every minute; and +251 _every second_. + +The annual _per capita_ consumption of cigars in the United States, +counting men, women and children, is eighty-six cigars. + +_If all the cigars smoked in the United States in one year were put +together, end to end, they would girdle the earth, at its largest +circumference, twenty-two times._ + +AS TO THE CIGARETTES, there are 23,736,190 of them consumed in the +United States every day; and 989,007 every hour; and 16,482 every +minute. With every tick of your watch, night and day, the year around, +the butts of 275 smoked-up cigarettes are dropped into the ash tray. + +Cigarette smokers in the United States, not counting those who roll +their own smokes from tobacco, spend $60,645,966.36 for the little +paper-covered rolls. + +If all the cigarettes smoked in the United States in one year were +placed end to end and stood up vertically they would make a slender +shaft rising 512,766 miles into the heavens. + +_If strung on a wire they would make a cable that would reach from +the earth to the moon and back again, with enough left over to circle +one-and-a-half times around the globe._ + +If this quantity of tobacco could be placed on one side of a huge +balancing scale it would take the combined weight of four vast armies, +each army consisting of 1,000,000 men, to pull down the other side of +the scale. + +The weight of the tobacco consumed in the United States in a year is +equal to the weight of the entire and combined population of Delaware, +Maryland, West Virginia, North Carolina, South Carolina, Georgia, +Florida, Tennessee and Alabama. + +[Illustration: HOW OUR FINGER PRINTS IDENTIFY US + +ARCH: IN THIS PATTERN RIDGES RUN FROM ONE SIDE TO ANOTHER, MAKING NO +BACKWARD TURN.] + +[Illustration: LOOP: SOME RIDGES IN THIS PATTERN MAKE A BACKWARD TURN, +BUT WITHOUT TWIST.] + + + + +The Story in a Finger Print[7] + + [7] Engravings and story by the courtesy of Scientific American. + + +Our Fingers. + +One of the most interesting facts about our fingers is that every +member of the human race, irrespective of age or sex, carries in +person certain delicate markings by which identity can be readily +established. If the inner surface of the hand be examined, a number +of very fine ridges will be seen running in definite directions, and +arranged in patterns, there being four primary types--arches, loops, +whorls, and composites. It has been demonstrated that these patterns +persist in all their details throughout the whole period of human life. +The impressions of the fingers of a new-born infant are distinctly +traceable on the fingers of the same person in old age. The fact that +these patterns on the bulbs of the fingers are characteristic of and +differentiate one individual from another, makes it an ideal means of +fixing identity. Even men who look so much alike that it is virtually +impossible to tell one from the other so far as facial characteristics +are concerned, can be identified by their finger impressions. + +Innumerable illustrations can be given of how the perpetrators of +crime have been identified and convicted by their finger prints. +Impressions left by criminals on such articles as plated goods, window +panes, drinking glasses, painted wood, bottles, cash boxes, candles, +etc., have often successfully supplied the clue which has led to the +apprehension of the thief or thieves. One of our illustrations is that +of a champagne bottle which was found empty on the dining-room table +of a house which had been entered by a burglar in Birmingham, England. +There was a distinct impression of a thumb mark on the bottle. An +officer of the Birmingham City Police took the bottle to New Scotland +Yard, London, and within a few minutes a duplicate print was found in +the records. The burglar was arrested the same evening. + +[Illustration: FINGER PRINTS OF DIFFERENT PEOPLE ARE DIFFERENT + +WHORL: RIDGES HERE MAKE A TURN THROUGH AT LEAST ONE COMPLETE CIRCUIT.] + +[Illustration: COMPOSITE: INCLUDES PATTERNS IN WHICH TWO OR MORE OF THE +OTHER TYPES ARE COMBINED.] + +Many similar instances could be given of how thieves have been caught +by handling bottles and glasses. On one occasion a burglar entered a +house in the West End of London, and before leaving helped himself +to a glass of wine. On the tumbler used he left two finger imprints, +and these were subsequently found, upon search in the records at New +Scotland Yard, to be identical with two impressions of a notorious +criminal, who was in due course arrested and sentenced to four years’ +imprisonment. + +A somewhat gruesome relic is a cash-box which bears the blurred thumb +mark of a man who was convicted of murder. The box was found in the +bedroom of a man and his wife who were murdered at Deptford, London, in +1905. The cash-box was taken to New Scotland Yard, and the impression +photographed and enlarged. Two brothers, suspected of the crime, were +arrested, and the thumb print of one was found to be identical with +that on the lid of the box. Our photograph of a gate recalls a curious +case that recently occupied the attention of a London magistrate. In +this instance a thief successfully climbed the gate, which was ten feet +high. In his attempt to reach the ground on the inner side he placed +his feet on the center cross-bar, at the same time holding the spikes +with his right hand. In this position he fell, and the ring he wore on +his little finger caught on the spike indicated by the arrowhead. This +caused him to remain suspended in the air until his weight tore the +finger from his hand. The ring with the finger was found on the spike, +and in due course was received at New Scotland Yard. An impression was +taken of the finger, and search among the records revealed a duplicate +print, which led to the man’s arrest. + +If a criminal handles a piece of candle or removes a pane of glass and +leaves these behind, it is a hundred to one he has left a valuable +clue for the police. The candle shown on the following page bears the +imprint of a man’s thumb, and was found in a house which a burglar had +entered. By handling the candle, the thief virtually signed the warrant +for his own arrest. + +The system was first used by the police in the Province of Bengal, +India, at the instigation of Sir William Herschel. Its value was at +once apparent. The work of the courts was considerably lightened, +as the natives recognized that a system of identification had been +discovered which was indisputable. Then from the police it was +introduced into various branches of the public service, and here again +its value was quickly demonstrated. When native pensioners died, for +instance, friends and relatives personated them, and so continued to +draw their allowances. By recording the identity of pensioners by +finger prints, this evil was quickly stamped out. + +[Illustration: IMPRESSIONS MADE BY THE FINGERS AND PALMS + +PALMARY IMPRESSIONS OF WHOLE HAND, SHOWING HOW IT IS COVERED WITH +RIDGES AND PATTERNS.] + +[Illustration: + + RIGHT HAND LEFT HAND + THUMB + FIRST FINGER + SECOND FINGER + THIRD FINGER + FOURTH FINGER + +FINGER IMPRESSIONS OF AN ORANG-OUTANG (ANTHROPOID APE) TAKEN AT THE +LONDON ZOO. THEY WERE MADE BY SCOTLAND YARD.] + +The wonderful lineations, in the form of ridges and patterns, which +adorn the palmar surface of the human hand, had, of course, been +known for many years. Mr. Francis Galton, the famous traveler and +scientist, was perhaps the first to give serious attention to the +subject of finger prints. He discovered many interesting facts about +them. Then, in 1823, Prof. Purkinje, of Breslau, read a paper before +the University of Breslau on the subject. Up to this date, however, no +practical use could be made of the impressions for the want of a system +of classification. Prof. Purkinje certainly suggested one, but little +notice appears to have been taken of it. + +Naturally, to be of any value to the police or to any government +department, it is absolutely essential to classify the prints in such +a way that they could be readily referred to and identity established +without undue delay. It was virtually left to Sir William Herschel, +of the Indian Civil Service, to invent a really practical system of +classification, so it may be claimed that the finger-print method +of identification, as at present adopted, is the discovery of an +Englishman. Then it is only fair to add that Sir Edward R. Henry, the +Commissioner of the Metropolitan Police of London, has also devoted +much time and study to the subject. His book, “Classification and Uses +of Finger Prints,” has passed through many editions, and has been +translated into several foreign languages. + +[Illustration: HOW THIEVES HAVE BEEN CAUGHT THROUGH FINGER PRINTS + +A CHAMPAGNE BOTTLE HAVING THUMB IMPRINT, WHICH LED TO ARREST OF A +BURGLAR.] + +[Illustration: CANDLE BEARING THUMB MARK OF A BURGLAR.] + +[Illustration: CASH-BOX IN BEDROOM OF MURDERED MAN AND WIFE. THE THUMB +IMPRESSION (POINTED AT BY ARROW) LED TO ARREST OF THE MURDERER.] + +Impressions are divided up into four distinct types or patterns. First, +we have arches in which the ridges run from one side to the other, +making no backward turn. In loops, however, some of the ridges do make +a backward turn, but are devoid of twists. In whorls some of the ridges +make a turn through at least one complete circuit. Under composites are +included patterns in which two or more of the former types are combined +in the same imprint. Although similarity in type is of frequent +occurrence, completely coincident ridge characteristics have never been +found in any two impressions. It is not necessary here to enter into +a detailed account as to how the classification of these wonderful +lineations of the human hand is effected. It is based on a number +value, attained by an examination, by means of a magnifying glass, of +the “deltas” and “cores,” which break up a collection into as many as +1024 separate primary groups, each of which can again, by a system +of sub-classification, be further split up into quite a number of +sub-groups. When the British police discover finger prints on articles +at the scene of crime, the latter are at once conveyed to New Scotland +Yard. If the impressions are very faint, a little powder, known to +chemists as “grey powder” (mercury and chalk), is sprinkled over the +marking and then gently brushed off with a camel-hair brush. This +brings out the imprint much more clearly. If one places his dry thumb +upon a piece of white paper no visible impression is left. If powder, +however, is sprinkled over the spot and then brushed off, a distinct +impression is seen. In the case of candles and articles of this nature, +a drop of printer’s ink is lightly smeared over an impression, in order +the more clearly to define the ridges and patterns. + +[Illustration: A SPIKE THAT CAUGHT A CRIMINAL + +ON THE SPIKE OF THE GATE (INDICATED BY AN ARROW) A CRIMINAL LEFT HIS +FINGER AND RING, WHICH LED TO HIS CONVICTION.] + +At the headquarters of the British police at New Scotland Yard they +possess special cameras and a dark room for photographing these thumb +marks. The dark room is 21 feet long and 7 feet wide. When finger +prints are required for production in court they are first enlarged +five diameters with an enlarging camera. The negatives are afterward +placed in an electric light enlarging lantern, with which it is +possible to obtain photographic enlargements of a thumb mark 36 inches +square. The lantern is arranged on a specially made table 12 feet long, +the lantern running between tram lines, so that when moved it is square +with the easel. + +Criminals have naturally come to dread the value of their thumb marks +as a means of identifying their movements. Some will try to obliterate +the markings by pricking their fingers, but so far this has not +availed them. To successfully accomplish this it would be necessary +to obliterate the whole of the palmary impressions on the tip of each +finger of each hand. + +Then the system, too, is far in advance of any other, both in +reliability and simplicity of working. Compared to anthropometry, for +instance, invented by M. Bertillon, in which measurements of certain +portions of the body are relied upon as a medium of identification, the +finger-print system is certainly preferable. In the first place, the +instruments are costly and are liable to get out of order; while the +measurements can only be taken by a fairly educated person, and then +only after a special course of instruction. In the finger-print system +the accessories needed are a piece of paper and ink, while any person, +whether educated or not, after half an hour’s practice, can take +legible finger prints. Then the classification of the latter is much +simpler and readier of access than the former. + +At the time of writing there are some 164,000 finger-print records in +the pigeon-holes at New Scotland Yard, and the number now being added +to it is at the rate of about 250 weekly. The system, too, is not only +in use in Great Britain, but in all the provinces of India, including +Burma, and in most of the British colonies and dependencies. It is +being rapidly extended, not only throughout Europe, but also through +North and South America. + +[Illustration: RECORDS OF FINGER PRINTS ARE KEPT AT HEADQUARTERS + + SPECIMEN FORM. + + This Form is not to be pinned. + + MALE. + + H.C.R. No. ..... + + Name ..... + + Aliases ..... + + Classification No. + + 28. MM. + 32. II. + + RIGHT HAND. + 1.—Right Thumb. + 2.—R. Fore Finger. + 3.—R. Middle Finger. + 4.—R. Ring Finger. + 5.—R. Little Finger. + + (Fold.) + + (Fold.) + + Impressions to be so taken that the flexure of the last joint shall + be immediately above the black line marked (Fold). If the impression + of any digit be defective a second print may be taken in the vacant + space above it. + + When a finger is missing or so injured that the impression cannot be + obtained, or is deformed and yields a bad print, the fact should be + noted under Remarks. + + LEFT HAND. + 6.—L. Thumb. + 7.—L. Fore Finger. + 8.—L. Middle Finger. + 9.—L. Ring Finger. + 10.—L. Little Finger. + + (Fold.) + + (Fold.) + + LEFT HAND. + + Plain impressions of the four fingers taken simultaneously. + + RIGHT HAND. + + Plain impressions of the four fingers taken simultaneously. + + Impressions taken by + + Classified at H.C. Registry by + + Tested at H.C. Registry by + + 13336 + + Rank + + Police } + Force. } + + Date + + Date + + (P.T.O.)] + +[Illustration: COMBS OF HONEY AS WE RECEIVE SAME] + + + + +The Story in a Honey Bee[8] + + [8] Pictures by Courtesy of E. R. Root Co. + + +Of all the insect associations there are none that have more excited +the admiration of men of every age or that have been more universally +interesting than the colonies of the common honey-bee. + +The ancients held many absurd views concerning the generation and +propagation of bees, believing that they arose from decaying animals, +from the flowers of certain plants, and other views equally ridiculous +from our present point of view. + + +Where Does Honey Come From? + +Honey is a sticky fluid collected from flowers by several kinds of +insects, particularly the honey bee; and the common honey bee from the +earliest period has been kept by people in hives for the advantage +and enjoyment which its honey and wax gives. It is found wild in +North America in great numbers, storing its honey in hollow trees and +other suitable locations, but not native to this country, having been +introduced in North America by European colonists. + +The story of the honey bee is one of the most interesting of all +stories of the living things found on the earth. The busy bee is the +ideal example of hard and persistent work and has for a long time been +the subject of interesting study for young and old. The bee is one of +the busiest of all of the world’s workers, and it is from the honey bee +that we get our expression “as busy as a bee”; such other expressions +as “to have a bee in one’s bonnet”; also such others as “quilting +bees” and “husking bees” are founded on the known activities of the +honey bee. The first expression means “to be flighty or full of whims +or uneasy motions” which comes from the restless habits of bees, and +“quilting bee” or “husking bee” originated from the knowledge that +bees work together for the queen. In a quilting bee or husking bee a +number of people get together and work together for a time for the +benefit of one individual. + +[Illustration: WORKER-BEE.] + +[Illustration: QUEEN-BEE, MAGNIFIED.] + +[Illustration: DRONE-BEE.] + + +Honey Is Produced by Bees which Live in Colonies. + +~HOW A BEE MAKES HONEY~ + +A colony of bees consists of one female, capable of laying eggs, +called the queen; some thousands of undeveloped females that normally +never lay eggs, the workers; and, at certain seasons of the year, many +males, the drones, whose only duty is to mate with the young queens. +These different kinds of individuals can readily be recognized by the +difference in size of various parts of the body, so that even the +novice at bee-keeping can soon recognize each with ease. This colony +makes its home in nature in a hollow tree or cave; but it thrives +perhaps even better in the hives provided for it by man. In a modern +hive, sheets of comb are placed in wooden frames which are hung in the +hive-box in such a way that they can be removed at the pleasure of the +bee-keeper. A sheet of comb is made up of small cells in which honey is +stored by the bees, and in which eggs are laid, and young bees develop. + +[Illustration: BEES LIVING ON COMBS BUILT IN THE OPEN AIR.] + + +How Does a Bee Make Honey from Flower Nectar? + +In the spring of the year the colony consists of a queen and workers, +there being no drones present at this time. During the winter the +bees remain quiet, and the queen lays no eggs, so that there are no +developing bees in the hive. The supply of honey is also low, for they +have eaten honey all winter, and none has been collected and placed +in the cells. As soon as the days are warm enough the bees begin to +fly from the hive in search of the earliest spring flowers. From these +flowers they collect the nectar, which is transformed into honey, and +pollen, which they carry to the hive on the pollen-baskets on the third +pair of legs. + +[Illustration: CUCUMBER-BLOSSOM WITH A BEE ON IT; CAUGHT IN THE ACT.] + +The nectar is taken by the bee into its mouth, and then passes to an +enlargement of the alimentary canal known as the honey-stomach, where +it is acted upon by certain juices secreted by the bee. The true +stomach lies just behind the honey-stomach; and if the bee needs food +for its own immediate use it passes on through the opening between the +two stomachs. On its arrival in the hive the bee places its head in one +of the cells of the comb and deposits there the nectar which it has +carried in. By this time the nectar has been partly transformed into +honey, and the process is completed by the bees by fanning the cells to +evaporate the excess of moisture which still remains. When a cell has +been filled with the thick honey the workers cover it with a thin sheet +of wax unless it is to be eaten at once. The pollen is also deposited +in cells, but is rarely mixed with honey. The little pellets which the +bees carry in are packed tightly into cells until the cell is nearly +full. If a cell of pollen be dug out of the comb, one can often see the +layers made by the different pellets. This collecting of nectar and +pollen continues throughout the summer whenever there are flowers in +bloom, and ceases only with the death of the last flowers in the autumn. + + +What Does the Queen Bee Do? + +Almost as soon as the honey and pollen begin to come in, the queen of +the colony begins to lay eggs in the cells of the center combs. The +title of queen has been given to the female bee which normally lays +all the eggs of the colony, under the supposition that she governs the +colony and directs its activities. This we now know to be an error, but +the name still remains. Her one duty in life is that of egg-laying. +She is most carefully watched over by the workers, and is constantly +surrounded by a circle of attendants who feed her and touch her with +their antennæ; but she in no way dictates what shall take place in the +hive. The eggs are laid in the bottom of the hexagonal cells, being +attached by one end to the center of the cell. The first eggs laid +develop into workers, and are deposited in cells one-fifth of an inch +across. As the colony increases in size by the hatching-out of these +workers, and as the stores of honey and pollen increase, the queen +begins to lay in larger cells measuring one-fourth of an inch, and +from the eggs laid in these cells drones (or males) develop. + +[Illustration: HOW HONEY DEVELOPS IN A COMB + +THE DEVELOPMENT OF COMB HONEY.] + +[Illustration: QUEEN-CELLS.] + +[Illustration: THE QUEEN AND HER RETINUE.] + +The eggs do not develop directly into adult bees, as might be inferred +from what has just been said; but after three days there hatches from +the egg a small white worm-like larva. For several days the larvæ +are fed by the workers, and the amount of food consumed is truly +remarkable. The larva grows rapidly until it fills the entire cell in +which it lives. The workers then cover the cell with a cap of wax, and +at the same time the larva inside spins a delicate cocoon under the cap. + +[Illustration: HOW THE EGG OF THE QUEEN BEE LOOKS + +EGG OF QUEEN UNDER THE MICROSCOPE.] + +[Illustration: HOW HONEY DEVELOPS IN A COMB + +THE DEVELOPMENT OF COMB HONEY.] + + +What Are Drone Bees Good for? + +The worker brood can at once be distinguished from the drone brood by +the fact that the workers place a flat cap over worker brood and a high +arched cap over drone brood; and this is often a great help to the +bee-keeper in enabling him to determine at once what kind of brood any +hive contains. Twenty-one days from the time the egg is laid the young +worker-bee emerges from its cell, having gone through some wonderful +transformations during the time it was sealed up, this stage being +known as the pupa stage. For drones the time is twenty-four days. + +[Illustration: HOW A SWARM WILL SOMETIMES OCCUPY A SMALL TREE AND BEND +IT OVER BY ITS WEIGHT.] + +About the time the drones begin to appear, the inmates of the hive +begin to prepare for swarming, which, to any one watching the habits +of bees, is one of the most interesting things which takes place in +the colony. Several young worker larvæ are chosen as the material +for queen-rearing, generally located near the margin of the comb. +The workers now begin to feed these chosen larvæ an extra amount of +food and at the same time the sides of the cells containing them are +remodeled and enlarged by the destruction of surrounding cells. The +queen (or royal) cell is nearly horizontal at the top, like the other +cells of the comb, and projects beyond them; but then the workers +construct another portion to the cell into which the queen larva moves. +This is an acorn-shaped cell placed vertically on the comb, about as +large as three ordinary cells. As the cell is being built, the queen +larva continues to grow until the time comes for her to be sealed up +and enter her pupa state. Although it takes the worker twenty-one days +to complete its development, the queen passes through all the stages +and reaches a considerably larger size in but sixteen days. + +[Illustration: THE DAILY GROWTH OF LARVÆ.] + +[Illustration: DRONE-COMB. + +WORKER-COMB.] + +[Illustration: HOW THE HONEY COMB IS MADE + +A STUDY IN CELL-MAKING. + +Note that the cells are made independent of each other, and that it is +the refuse wax, like droppings of mortar in brick-laying, that seems to +tumble into the interstices to fill up.] + +In the swarming season, at about the time the new queens are ready to +leave their cells, the old queen leaves the hive and takes with her +part of the workers, this being known as swarming. + +[Illustration: CLIPPING THE QUEEN BEE’S WINGS + +HOW TO BUMP THE BEES OFF A COMB.] + +[Illustration: MANNER OF USING GERMAN BEE-BRUSH] + +[Illustration: M. G. Dervishian’s method of catching queens, for caging +or clipping their wings, by means of a jeweler’s tweezers.] + +[Illustration: “THE PROOF OF THE PUDDING IS IN THE EATING.”] + +[Illustration: WHAT AN APIARY LOOKS LIKE + +AN APIARY IN SUMMER. + +This photo shows the windbreak of evergreens surrounding the yard. The +house-apiary is shown in the background, the upper story of which is +used as a workshop. A trellis of grapevines is placed in front of each +hive. In summer there is ample shade, and in the fall and early spring +the leaves are shed, leaving plenty of sun to strike the hives when it +is most needed.] + +[Illustration: HOW THE HONEY MAN HANDLES THE BEES + +A SWARM ENTERING A HIVE.] + +[Illustration: A LIVE BEE-HAT.] + +[Illustration: A FRAME OF BEES, SHOWING ONE WAY OF HOLDING AN UNSPACED +FRAME.] + + +How Do Bees Build the Honey Comb? + +In the hands of a bee-keeper the departing swarm will be put into +another hive provided he wishes to increase the number of his colonies; +but in a state of nature the swarm will find an old hollow tree or +some similar place in which to establish itself. The bees, before +leaving their old hive, fill themselves with honey until the abdomen +is greatly distended, and for this reason it is not necessary for them +to collect nectar for a day or two, for they have other work to do. +Some of the bees begin to clean out the new quarters and get it fit for +occupancy; but most of them begin the construction of new combs. To +do this they suspend themselves in curtains from the top of the hive, +and remain motionless for some time. The wax used in building comb is +secreted by the workers in eight small pockets on the lower side of the +abdomen while they thus hang in curtains. Finally, after enough wax has +been formed, they begin to build. The small flakes of wax are passed +forward to the mouth, there mixed with a salivary secretion to make the +wax pliable, and then are placed on the top of the hive by the first +comb-builders. Other workers then come and place their small burdens of +wax on those first deposited, and this continues until the combs are +finished. There is more to comb-building than the mere sticking on of +wax plates, however, and nothing in all bee instincts is more wonderful +than the beautiful plan on which they build the comb. The cells are +hexagonal in shape, so that each cell in the center of the comb is +surrounded by six others. Nor is this the only remarkable thing in +their architecture, for each comb is composed of a double row of cells, +the base of each cell being formed of three parts, each one of which is +likewise a part of a separate cell of the other side of the comb. By +this method the bees obtain the greatest possible capacity for their +cells, with the least expenditure of wax. The accuracy of the cells of +the comb has in all ages been an object of admiration of naturalists +and bee-keepers. + +As soon as there are some cells constructed, and even before the cells +are entirely completed, the queen begins to lay eggs, and the workers +begin to collect the stores of honey and pollen. They also collect in +considerable quantity a waxy substance from various trees, commonly +called propolis, with which they seal the inside of the hive, closing +up all openings except the one which serves as the entrance. + +[Illustration: HOW THE HONEY BEE DEFENDS HIMSELF + +EFFECT OF A STING NEAR THE EYE.] + +The cells which are used for the storage of honey generally slant +upward slightly to help keep the honey from running out. Queen-cells +are made only when a new queen is to be reared. + + +Can a Bee Sting? + +It is true that bees cannot bite and kick like horses, nor can they +hook like cattle; but most people, after having had an experience with +bee-stings for the first time, are inclined to think they would rather +be bitten, kicked, and hooked, all together, than risk a repetition of +that keen and exquisite anguish which one feels as he receives the full +contents of the poison-bag. + + +What Happens When a Bee Stings? + +After the bee has penetrated the flesh on your hand, and worked the +sting so deeply into the flesh as to be satisfied, it begins to find +that it is a prisoner, and to consider means of escape. It usually +gets smashed at about this stage of proceedings, unless it succeeds +in tearing the sting--poison-bag and all--from the body; however, if +allowed to do the work quietly it seldom does this, knowing that such a +proceeding seriously maims it for life, if it does not kill it. After +pulling at the sting to see that it will not come out, it seems to +consider the matter a little, and then commences to walk around it, +in a circle, just as if it were a screw it was going to turn out of a +board. If you will be patient and let it alone, it will get it out by +this very process, and fly off unharmed. I need not tell you that it +takes some heroism to submit patiently to all this maneuvering. The +temptation is almost ungovernable, while experiencing the intense pain, +to say, while you give it a clip, “There, you little beggar, take that, +and learn better manners in future.” + +Well, how does every bee know that it can extricate its sting by +walking around it? Some would say it is instinct. Well, I guess it is; +but it seems to me, after all, that it “sort o’ remembers” how its +ancestors have behaved in similar predicaments for ages and ages past. + + +Odor of the Bee-sting Poison. + +After one bee has stung you, if you remain where you were stung, the +smell of the poison, or something else, will be pretty sure to get more +stings for you, unless you are very careful. It has been suggested that +this is owing to the smell of the poison, and that the use of smoke +will neutralize this scent. This probably is so. + + +What Should I Do If I Am Stung by a Bee? + +The blade of a knife, if one is handy, may be slid under the +poison-bag, and the sting lifted out, without pressing a particle more +of the poison into the wound. When a knife-blade is not handy, push +the sting out with the thumb or finger nail in much the same way. It +is quite desirable that the sting should be taken out as quickly as +possible, for if the barbs once get a hold in the flesh, the muscular +contractions will rapidly work the sting deeper and deeper. Sometimes +the sting separates, and a part of it (one of the splinters, so to +speak) is left in the wound; it has been suggested that we should be +very careful to remove every one of these tiny points; but after trying +many times to see what the effect would be, I have concluded that they +do but little harm, and that the main thing is, to remove the part +containing the poison-bag before it has emptied itself completely into +the wound. + + +Why Are Some Races White, and Others Black, Yellow and Brown? + +What you eat determines your color, according to Bergfield, a German +investigator. Not necessarily that you yourself could effect any change +in color, but your ancestors for thousands of years have unconsciously +been influenced by the food they have eaten and the drinks they have +drunk. + +For instance, the original men were black, says Bergfield. Their chief +diet was of vegetables and fruits, he explains, and these same food +contains manganates that are not unlike iron. Dark browns and blacks +result from this combination. It is a scientific fact that negroes who +drink milk and eat meat are never as dark as those who eat vegetables. + +Again, Mongols are yellow because they have descended from races that +were fruit-eating, and who, making their way into the deepest nooks +and widest plains of Asia, developed into shepherds and lived largely +on milk. Of course it is now known that milk contains a certain +percentage of chlorine, and has a decidedly bleaching effect. In the +case of Caucasians, they are said to have become white by adding salt +to their foods, which common salt is a strong chloride, and powerful in +bleaching the skin. + +[Illustration: A HIDE HOUSE] + + + + +The Story in a Piece of Leather[9] + + [9] Pictures by courtesy of Endicott, Johnson & Co. + + +Where Does Leather Come From? + +Leather is made by treating the hides of various animals such as the +calf, cow and horse. These are the principal animals from which we +obtain hides for making leather to make shoes. Before the hides are +fit for making shoes, they must be taken to a tannery where they are +prepared and tanned. + +In viewing a tannery, we enter first the enormous hide house. It is +long, damp and dark. Here the hides are collected from all over the +world and stored, awaiting their turn for tanning. We follow a small +car of these hides into the beamhouse. We see the hides loaded into a +vat. They are soaked, resoaked, softened and split into sides. This +operation, while simple, holds your attention longer perhaps than any +of the others. Several hides after being softened are thrown over +a sort of saw-horse, the lot number is stamped on the hide in such +a manner that it appears on each side after being split. With an +unusually long bladed knife the workman quickly cuts down through the +center and the hides which are now called sides, fall to the floor. +They are next hooked together and pass on through vat after vat of lime +solution which loosens the hair and superfluous flesh. At the end of +this long chain of vats, we see the sides awaiting their turn at the +first unhairing machine, where all the hair is removed and then to the +fleshing machine, where the flesh is taken off and the sides are again +loaded in a car and pass on to the tanyard. + +[Illustration: HOW THE HIDES ARE TREATED + +THE TAN YARD + +We resume our travels, following a car of sides from the beamhouse to +the sole leather tanyard. There are about 40 operations in the tanning +of sole leather, requiring about 100 days to produce first quality +leather. In the tanyard, we see more than 500 vats, each holding 300 +sides, weighing about 23 pounds apiece. Each vat contains about 3000 +gallons of liquor at an approximate cost of $100 a vat. Here we see +the sides slipped over sticks and placed in vats six feet deep, where +they receive the tanning, the real tanning process which preserves the +fibers giving the leather its life and long wearing qualities. + +From the tanyard we go to the big wringers where the liquor is wrung +out, the hides are milled, dried and loaded on cars for the drying +loft, where they are allowed to dry or season preparatory to rolling. +This long building is sectioned off every 50 feet into chambers, where +the hides are hung in the same manner as in the vats. The temperature +of each room is changed from the outside temperature to a heat of 115 +degrees, at which temperature the hides are dried and are ready for +rolling.] + +[Illustration: In the rolling room, we see an operation requiring skill +and quickness of eye. The rollers pass to and fro over the side, which +is now hard and stiff, with a pressure of 300 tons. This rolling or +finishing gives it a high polish and we see a beautiful side of sole +leather, weighing from 18 to 25 pounds.] + +[Illustration: HOW UPPER SHOE LEATHER IS TANNED + +In the upper leather tannery we see the various operations preparatory +to the actual operation of tanning the hide, about the same as in +the sole leather tannery, with this difference: Upper leather in +this tannery is generally chrome tanned, a process requiring 30 days +and instead of vats sunken in the ground we see huge rolling drums +revolving at a rapid rate. This process is the most up-to-date method +and absolutely insures the wearing qualities of the leather. This +leather is very tough, yet is just as soft and pliable as glove leather +and as comfortable to the feet. It does not harden with age, nor does +it stiffen after being wet.] + +[Illustration: UNHAIRING MACHINE + +One of the most interesting sight while going through the tanneries is +the process of disposing of waste materials, such as hair, fleshings +and the sediments from the lime and sulphur vats. + +The hair is separated into white, brown and black colors, each color +taking its turn through the huge mill or gin where the hair is dried +and afterwards baled. The brown and black are sold to plasterers. Those +who purchase the white often mix it with wool and use it for making +many useful articles. + +The fleshings and trimmings are sold to manufacturers of glue.] + +[Illustration: The Ancient Sandal Maker as pictured on the wall of the +ruined temples at Thebes, Egypt.] + + + + +The Story in a Pair of Shoes[10] + + [10] Pictures by Courtesy of United Shoe Machinery Co. + + +Who Made the First Shoes? + +~WHERE SHOES COME FROM~ + +The making of shoes is one of the oldest arts of which there is any +human knowledge. Long before primitive man devised any method of +recording his exploits or thoughts, he contrived--through necessity--a +method of protecting his feet from the rough way or hot sands over +which he was obliged to travel in his search for food and shelter. + +That foot covering antedates clothing or ornaments is shown from the +fact that the primitive savage to-day, devoid of clothing or ornament, +is almost invariably found with a crude form of foot protection and +there is scarcely a tribe or nation without it’s traditions of the +shoe--its mysterious power for good or evil. + + +What Was the First Foot Covering Like? + +The first foot covering devised was undoubtedly a simple form of +sandal--a rough bit of hide, wood or plaited grass held to the foot by +means of thongs, generally brought up between the toes and tied about +the ankle. This form of foot covering is depicted in records of the +greatest antiquity: in the ruined temples at Thebes Egypt, the ancient +sandal maker is shown at his task; the Assyrian bricks show the ancient +warriors and people of that time wearing the simple sandal. + +The dispersion of the human races and the wandering of tribes into +colder climates brought the necessity for more thorough protection +for the feet and body, and that this was accomplished was shown in +the gradual increase in the number of straps or thongs which held the +sandal in place and, in the colder climates, in the contrivance of +a bag-like foot covering--traces of which are found even now in the +Indian moccasin and the foot covering of the Eskimo. In all colder +countries this type of footwear is still in evidence, the seam around +the outline of the foot being a relic of the puckering string which +held the bag-like covering to the foot. + +[Illustration: Ancient sandal showing puckering string and thongs for +holding it on foot.] + +[Illustration: JAPANESE “ZORI” + +A flat sandal with felt sole. Also showing “Tabi” or glove-like sock +worn by Japanese.] + +The sandal was developed and adorned by the Greeks, but it was not +until the days of the Roman Empire that anything approaching the +present form of shoes was designed. In this period a form of foot +covering was developed--that was appropriated by the Emperor and worn +by him only--which covered the entire foot with the exception of the +toes. + +[Illustration: + + THE + EVOLUTION + OF THE + SANDAL + TO THE + SHOE] + +[Illustration: ANCIENT AND MODERN FORMS OF SANDALS + +Japanese Astrida or Rough Weather Clog.] + +[Illustration: Ancient Turkish Bath Slipper.] + +[Illustration: The Crakrow or Poulaine showing clearly traces of the +oriental origin of this design.] + +[Illustration: Home made sandal of Siberian Peasant. Showing puckering +string and key strap.] + +[Illustration: JAPANESE WARY + +A primitive form of foot covering very generally used by Japanese at +the present time.] + +[Illustration: Modern sandal issued by the Mexican Government for wear +of soldiers.] + + +The Boot Developed from the Sandal. + +It was but a step from this form of foot covering to the boot which +covered not only the foot but the lower leg as well and which came +widely into use afterwards in the form of the Jack-boot. + +Up to the fourteenth century there had been little in the way of +development of foot covering, but it is well established that in the +year 1408 there were shoemakers’ guilds in Europe. Some of these +were semi-religious in character, the members working in communities +and sharing in the general product of their toil. Guilds of this +period were very generally dedicated to either Saint Crispin or Saint +Crispianus (the patron saint of shoemaking), and even to this day +the birthday of Saint Crispin is celebrated in some of the English +shoemaking guilds on October 25. The ceremonies attending the +celebration in the olden days were of a very elaborate nature. + +~THE SHOE WHICH THE CHURCH AND LAW FORBADE~ + +In the process of time the shoes began to lose the crude nature and +design in which the Dark Ages had held them and developed a style the +first of which was apparent in the gradual elongation of the toes, +the custom said to have been introduced by Henry, Duke of Anjou, +and these shoes were known as “Crakrows” or “Poulaines.” The style +finally ran to such extremes that effort was made to stop it by the +church and government, but with indifferent success until finally its +end was accomplished by the imposing of summary fines and threat of +excommunication by the church. + +[Illustration: THE CRAKROW OR PEAKED SHOE OF THE FOURTEENTH CENTURY] + +Immediately the style went to the other extreme and the toes became +very broad, as evidenced in the period of Elizabeth, and in some +instances the shoes were as broad as six inches at the toe. They were +made of velvet and were slashed to show the satin lining. + + +Who Made the First Shoes in America? + +The first shoemaking in America is recorded when Thomas Baird arrived +on the second voyage of the Mayflower in 1628. Baird was under contract +with the Plymouth Company to make shoes for the colonists and brought +with him divers hides, etc., for this purpose. It was recorded that in +1636 a planter in Virginia employed six shoemakers to make shoes for +his slaves. + +That in the early history of the country the art of making shoes had +become of considerable importance is shown by the very summary laws +passed by the different colonies regulating the industry. Particularly +was this so in the Province of Pennsylvania which, in 1721, placed upon +its statute book most drastic laws regarding the making of shoes and +regulating the prices to be charged therefor. + +Shoemaking in New England early received impetus from the arrival of +one Phillip Kirtland, a Welshman, who came to Lynn, Mass., in 1636. +He was an experienced shoemaker and taught his art to many of the +colonists in his vicinity. + +Shoemaking in this locality was further advanced by the arrival of +John Adams Dagyr, who settled in Lynn in the year 1750. Dagyr was a +celebrated shoemaker and was enabled, from his own means, to secure the +best examples of work from abroad. He possessed the peculiar quality +of being able to teach the art to those who came under his charge. + +The fame of New England made shoes was due largely to the teachings +of these men and the industry has continued to be one of the first in +importance. In Massachusetts alone, according to the census of 1910, +over 40 per cent of the entire value of shoes in the United States was +produced. + +The young man of this period, who essayed to learn the shoemaking +trade, was ordinarily apprenticed for a term of seven years under the +most rigorous terms, as shown in some of the indentures of that period +which are still in existence. He was instructed in every part of the +trade and, upon completion of his term of service, it was the custom +for the newly fledged shoemaker to start what was known as “whipping +the cat”--which meant journeying from town to town, living with a +family while making a year’s supply of shoes for each member thereof, +and then leaving to fill other engagements previously made. + +It was soon found that the master workman could largely increase his +income by employing other men to do certain portions of the work, while +he directed their efforts, and this gradually lead to a division of +the labor and was the beginning of a factory system--which has been in +process of development from that time. + +In the year 1795 it is recorded that there were in the city of Lynn, +Mass., over two hundred master workmen, employing over six hundred +journeymen, and that they manufactured shoes at the rate of about one +pair per day per man. + +Factory buildings, as the words would be known to-day, were practically +unknown at that time. The small buildings, about ten feet square, were +in the back yards of many homes and in these little shops were employed +from three to eight men. + +Strange as it may seem, prior to the year 1845 there had been little +change in the tools employed in making shoes. The workman of that +period, seated at his low bench, used practically the same implements +that were employed by his prototype, the ancient sandal-maker of +Egypt. The lap stone, the hammer, the crude needle and the knife being +practically the only tools used. Not that there had been no effort to +perfect machinery for this purpose; Napoleon I, in his endeavor to +secure better shoes for his soldiers, had offered great rewards for +the perfecting of shoe machinery that would accomplish this purpose, +but although great effort had been made there had been no successful +machinery produced. + +In this year 1845 the first machine to be widely adopted by the +industry was perfected. It was a simple form of rolling machine, which +took the place of the lap stone and hammer used by the shoemakers for +toughening the leather, and it is said that a man could, in half an +hour, obtain the same results from this machine that would require a +day’s labor on the part of the hand workman employing the old method of +pounding. + +This was followed in 1848 by the very important invention by Elias Howe +of the sewing machine--which was not adapted for use in connection with +sewing leather until several years later. It started, however, an era +of great activity among inventors and in 1857 there was perfected a +machine for driving pegs, which came into successful operation. + + +The First Machine for Making Shoes. + +This was shortly followed by a very important invention by Lyman E. +Blake, of Abington, Mass., of a machine for sewing the soles of shoes +and this afterwards became famous as the “McKay Sewing Machine.” This +invention of Blake’s was purchased by Gordon McKay, who spent large +sums of money in perfecting it, and the first machine was established +in Lynn in 1861. The results obtained in the early stages of the +machines were of an indifferent nature and it was only after large +expenditures and the hiring of a number of different inventors to work +upon it that a successful machine was produced. + +[Illustration: BOOTS OF THE CAVALIERS AND POSTILLIONS + +FRENCH POSTILLION BOOT OF THE FIFTEENTH CENTURY] + +[Illustration: THE CAVALIER BOOT OF THE FIFTEENTH CENTURY] + +[Illustration: MILITARY JACK BOOT OF CROMWELL’S TIME] + +[Illustration: MILITARY JACK BOOT OF SIXTEENTH CENTURY.] + +~HOW SHOE MACHINERY WAS DEVELOPED~ + +While the quality of work was pronounced by manufacturers to be a +success, few had any faith in the possibility of manufacturing shoes +by machinery and McKay met with constant rebuffs in his endeavor +to introduce his machine. It is recorded that in his desperation +he finally offered to sell all the patent rights in machines which +he owned to a syndicate of Lynn manufacturers for the sum of +$250,000.00--the amount he had expended--but the offer was refused. + +In his dilemma McKay at last offered to shoe manufacturers the use of +his machines on a basis, which afterwards became famous and an inherent +part of the shoe industry known as “royalty,” whereby McKay placed his +machines with manufacturers and participated to a small extent in the +amount of money saved. Owing to the fact that shoemakers were leaving +rapidly for the front and that there was a great scarcity of footwear, +the manufacturers gladly accepted this proposition and the machines +were very rapidly introduced. + +The success of his early machines accomplished, McKay set about the +perfecting of others that would do different parts of the work and +there was accordingly great activity on the part of inventors in +their endeavor to perfect machines for the wide variety of uses made +necessary in the preparation of leather for shoemaking. There were soon +machines on the market for a wide variety of purposes--including the +lasting of the shoe, cutting the leather and for many other processes +necessary in making a complete shoe. + +Contemporary with the early success of the McKay machines, a French +inventor, August Destoney, conceived the idea of making a machine +which would sew turned shoes--then a popular type of footwear for +women. After several years of endeavor he finally secured the interest +of John Hanan, a famous shoemaker of that time in New York City, and +through him the interest of Charles Goodyear--nephew of Goodyear of +India-rubber fame. + +No sooner had the machine become perfected for the sewing of turned +shoes, however, than he set to work to make changes which would fit +it to sew welt shoes. (The welt shoe has always been considered the +highest type of shoemaking, as, by a very ingenious process, a shoe +is made which is perfectly smooth inside; all the other types having +a seam of thread or tacks inside which make them of considerable +disadvantage. He was able to accomplish this a few years later, +although the machines were not in extended use until about 1893, when +auxiliary machines for performing important parts of the work were +perfected; and from that time headway was made in the manufacture of +this high grade type of footwear. + +The development of the industry--which has been very rapid with the +introduction of machinery--suffered materially in the latter part of +the last century through the bitter rivalry of machinery manufacturers, +a common process being the enjoining of manufacturers from the use of +machines on which it was claimed the patents were infringed and this +created a state of great uncertainty in the minds of many of those +manufacturing shoes. + +This condition finally found its solution in the formation of one large +corporation, known in the shoe industry as the “United Shoe Machinery +Company,” which purchased the patents for a sufficient number of +machines to form a complete system for the “bottoming”--or fastening +the soles and heels of shoes--and finishing them. + +These machines have been the subject of constant improvement and +others have been perfected to take care of operations which, prior to +their introduction, were purely hand operations. Each machine has been +standardized and so adapted to meet the requirements of those used in +connection with it that they collectively form the most remarkable and +efficient system of machines used at the present time. + +Mention is made of this company owing to the important position it +has taken in the organization and advancement of the industry, the +American-made shoe being the one commodity of world-wide consumption +whose supremacy is not contested. + +[Illustration: MY LADY’S SLIPPERS OF EARLY TIMES + +EMBROIDERED RIDING BOOT WORN BY NOBLES DURING LAST DAYS OF POLISH +INDEPENDENCE] + +[Illustration: EMBROIDERED RIDING BOOT FROM PERSIA OF ABOUT 1850] + +[Illustration: FRENCH CALF BOOT MADE IN NEW YORK CITY, 1835] + +[Illustration: LADY’S SHOE--PERIOD OF THE FRENCH REVOLUTION] + +[Illustration: LADY’S SHOE--PERIOD OF LOUIS XVI. + +Has wooden heel.] + +[Illustration: LADY’S ADELAID OR SIDE LACED SHOE--PERIOD 1830 TO 1870] + +[Illustration: + + CHANNEL LIP + + CROSS-SECTION OF INSOLE + + WOODEN LAST—DETERMINES SIZE AND SHAPE OF SHOE + + AN INSOLE + + AN INSOLE TACKED TO BOTTOM OF LAST + +THE BEGINNING OF A SHOE] + + + + +How Shoes Are Made by Machinery + + +At the present time the types of shoes ordinarily made are but five: +the “peg” shoe, which is the cheapest type of shoe made; the “standard +screw,” which is used in the soles of the heaviest types of boots; +the “McKay sewed,” which is made after the fashion established by +Gordon McKay; the “turn” shoe, a light type of shoe which was invented +centuries ago and which is still worn at this time to a limited extent; +and the “Goodyear welt,” which has been universally adopted as the +highest type of footwear. + +For this reason, this type of shoe has been selected to show the +methods employed in making shoes. + +THE GOODYEAR WELT SHOE.--A Goodyear Welt shoe in its evolution from +the embryonic state in which it is “mere leather and thread” to the +completed product, passes through one hundred and six different pairs +of hands and is obliged to conform to the requirements of fifty-eight +different machines, each performing with unyielding accuracy the +various operations for which they were designed. + +It might seem that in all this multiplicity of operations confusion +would occur, and that the many details and specifications regarding +material and design of any given lot of shoes in process of manufacture +would become hopelessly entangled with those of similar lots undergoing +the same operations. But such is not the case; for, when an order +is received in any modern and well-organized factory, the factory +management promptly take the precaution to see that all the details +regarding the samples to which the finished product is to conform are +set down in the order book. Each lot is given an order number and this +number, together with the details affecting the preparation of the +shoe upper, are written on tags--one for each two dozen shoes--which +are sent to the foreman of the cutting room. Others containing details +regarding the sole leather are sent to the sole leather room, while a +third lot is made out for the guidance of the foreman of the making or +bottoming room, when the different parts which have received attention +and been prepared according to specifications in the cutting and sole +leather rooms are ready to be assembled for the making or bottoming +process. If the tags which were sent to the cutting room were followed, +it would be found that on their receipt the foreman of this department +figured out the amount and kind of leather required, the kind of +linings, stays, etc., and that the leather, together with the tags +which gave directions regarding the size, etc., was sent to one of the +operators of the Ideal Clicking Machine. + +~SHOEMAKING MACHINERY IS ALL BUT HUMAN~ + +This machine has been pronounced one of the most important innovations +that have been made in the shoe manufacturing industry during recent +years, as it performs an operation which has heretofore successfully +withstood every attempt at mechanical aid. Prior to its introduction, +the cutting of upper leather was accomplished by the use of patterns +made with metal edges, which were laid upon the leather by cutter, who +then ran a small sharp knife along the edges of the pattern, cutting +the leather to conform to it. This was a slow and laborious process, +and if great care was not taken, there was a tendency to cut away from +the pattern; and in many cases, through some slip of the knife, the +leather was cut beyond the required limits. + +This machine has a cutting board very similar to those which were used +by the hand workman and over it is a beam which can be swung either +to the right or to the left, as desired, and over any portion of the +board. Any kind of skin to be cut is placed on the board, and the +operator places a die of unusual design on it. Grasping the handle, +which is a part of the swinging beam, he swings the beam over the die, +and on downward pressure of the handle a clutch is engaged which brings +the beam downward, pressing the die through the leather. As soon as +this is accomplished, the beam automatically returns to its full height +and remains there until the handle is again pressed. + +The dies used are but three-quarters of an inch in height and are so +light that they do not mar the most delicate leather when placed upon +it. They enable the operator to see clearly the entire surface of the +leather he is cutting out, and it is obvious that the pieces cut by the +use of any given die must be identically the same. + +After the different parts required by the tag have been cut out by the +operator of the Clicking Machine, some of the edges which show in the +finished shoe must be skived or thinned down to a beveled edge. This +work is performed by the Amazeen Skiving Machine--a wonderful little +machine in which the edge to be skived is fed to a sharp revolving +disk that cuts it down to the desired bevel. The machine does the +work in a very efficient manner, conforming to all the curves and +angles. This skiving is done in order that the edges may be folded, +to give the particular edge on which it is performed a more finished +appearance. The skived edges are then given a little coating of cement +and afterwards folded on a machine which turns back the edge and +incidentally pounds it down, so that it presents a very smooth and +finished appearance. + +Aside from the work of skiving toe caps and folding them, there is +generally a series of ornamental perforations cut along the edge of +the cap. This is done very often by the Power Tip Press, by means of +which the piece to be perforated is placed under a series of dies which +cuts the perforations in the leather according to a predetermined +design, doing the work all at one time. The number of designs used +for this purpose are many and varied, combinations of different sized +perforations being worked out in innumerable designs. + +On one of the top linings of each shoe there has been stamped the +order number, together with the size of the shoe for which the linings +were intended. After all the linings have been prepared in accordance +with the instructions on the tag, they, in connection with the various +parts of the shoe, receive attention from the Stitchers, where all the +different parts of the upper are united. The work is performed on a +range of wonderful machines, which perform all the different operations +with great rapidity and accuracy. + +At the completion of these operations the shoe is ready to receive the +eyelets, which are placed with remarkable speed and accuracy by the +Duplex Eyeletting Machine. This machine eyelets both sides of the shoe +at one time with bewildering rapidity. The eyelets are securely placed +and accurately spaced; and as both sides of the upper are eyeletted at +one time, the eyelets are placed directly opposite each other, which +greatly helps the fitting of the shoe, as thereby the wrinkling of the +shoe upper is avoided. + +With the completion of this operation, the preparation of the shoe +upper is finished, and the different lots with their tags are sent to +the bottoming room to await the coming of the different sole leather +portions of the shoe. These have been undergoing preparation in the +sole leather room, where on receipt of tag the foreman has given +directions for the preparation of outsoles, insoles, counters, toe +boxes and heels, to conform with the requirements of the order. + +The soles are roughly died out from sides of sole leather on large +Dieing-out Machines, which press heavy dies down through the leather; +but to make them conform exactly to the required shape, they are +generally rounded out on a machine known as the “Planet Rounding +Machine,” in which the roughly died-out piece of leather is held +between clamps, one of which is the exact pattern of the sole. On +starting the machine, a little knife darts around this pattern, cutting +the sole exactly to conform with it. + +The outsole is now passed to a heavy Rolling Machine, where it is +subjected to tons of pressure between heavy rolls. This takes the place +of the hammering which the old-time shoemaker gave his leather and +brings the fibres very closely together, greatly increasing its wear. + +This sole is next fed to a machine called the “Summit Splitting +Machine--Model M,” which reduces it to an exactly even thickness. The +insole--which is made of very much lighter leather--is prepared in +much the same manner, and in this way it will be noticed that both the +insole and outsole are reduced to an absolutely uniform thickness. + +The insole also receives further preparation; it is channeled on the +Goodyear Channeling Machine. This machine cuts a little slit along the +edge of the insole, extending about one-half inch towards its center. +It also cuts a small channel along the surface. + +The lip which has been formed by the Goodyear Channeling Machine is now +turned up on the Goodyear Lip Turning Machine, so that it extends out +at a right angle from the insole, forming a lip or shoulder against +which the welt is sewed. The cut which has been made on the surface +inside this lip serves as a guide for the operator of the Welt Sewing +Machine, when the shoe reaches that stage. + +The heels to be used on these shoes have also been formed from +different lifts of leather which are cemented together. The heel is +then placed under great pressure, giving it exact form and greatly +increasing its wear. + +~THE DIFFERENT PARTS OF THE SHOE COME TOGETHER~ + +The counters are also prepared in this room, as well as the toe boxes +or stiffening, which is placed between the toe cap and the vamp of +the shoe. When these are all completed, they are sent to the making +or bottoming room, where the completed shoe upper is awaiting them. +Here a wonderfully ingenious little machine called the “Ensign Lacing +Machine,” passes strong twine through the eyelets and in a twinkling +ties it automatically. This is done so that all parts of the shoe will +be held in their normal position while the shoe is being made. The +knot tied by this machine is perfect and is performed with mechanical +exactness. On high-grade shoes this work was formerly performed by +hand and it will be readily recognized how difficult it was to obtain +uniformity. The spread of the upper at the throat can be regulated +perfectly when this machine is used. The different parts of the shoe +now commence to come together. The workman places the toe box, or +stiffening, in the proper location as well as the counter at the +heel, and draws the upper over the last. To the bottom of this last +has already been tacked by means of the U. S. M. Co. Insole Tacking +Machine--which drives tacks automatically--the insole, which, it will +be noticed, conforms exactly to the shape of the bottom of the last. +This last, made of wood, is of the utmost importance, for upon the last +depends the shape of the shoe. + +[Illustration: EACH SHOE MACHINE DOES SOMETHING DIFFERENT + +ASSEMBLING MACHINE + +Operator locates back seam of upper on last. Machine drives two tacks +which hold it in place.] + +The shoe as completed up to this point with the parts mentioned +fastened together as shown, is now ready for assembling. The workman, +after placing the last inside the shoe upper, puts it on the spindle of +the Rex Assembling Machine, where he takes care that the seam at the +heel is properly located. He presses a foot lever and a small tack is +driven part way in, to hold the upper in place. He then hands it over +to the operator of the Rex Pulling-Over Machine. + +[Illustration: PULLING-OVER MACHINE + +Draws shoe upper smoothly down to last. Operator adjusts it so that +each seam occupies correct position on last. Machine automatically +drives back to hold it in place.] + +This machine is a very important one; for as the parts of the shoe +upper have been cut to exactly conform to the shape of the last, it is +necessary that they should be correctly placed on the last to secure +the desired results. The pincers of this machine grasp the leather at +different points on each side of the toe; and the operator, standing +in a position from which he can see when the upper is exactly centered, +presses a foot lever, the pincers close and draw the leather securely +against the wood of the last. At this point the operation of the +machine halts. By moving different levers, the workman is able to +adjust the shoe upper accurately, so that each part of it lies in the +exact position it was intended when the shoe was designed. When this +important operation has been completed, the operator again presses a +foot lever, the pincers move toward each other, drawing the leather +securely around the last, and at the same time there are driven +automatically two tacks on each side and one at the toe, which hold the +upper securely in position. These tacks are driven but part way in, so +that they may be afterward removed. + +[Illustration: THE LASTING MACHINE ONE OF THE MOST IMPORTANT + +HAND METHOD LASTING MACHINE + +Last sides of shoe.] + +[Illustration: LASTING MACHINE + +Last toe and heel of shoe.] + +The shoe is now ready for lasting. This is one of the most difficult +and important parts of the shoemaking process, for upon the success of +this operation depends in a great measure the beauty and comfort of the +shoe. The Consolidated Hand Method Welt Lasting Machine, which is used +for this purpose, takes its name from the almost human way in which it +performs this part of the work. It is wonderful to observe how evenly +and tightly it draws the leather around the last. At each pull of the +pincers a small tack driven automatically part way in holds the edge +of the upper exactly in place, so that in the finished shoe every part +of the upper has been stretched in all directions equally. The toe and +heel of the shoe are considered particularly difficult portions to last +properly. This important part of the work is now being very generally +performed on the U. S. M. Co. Lasting Machine--No. 5, a machine of +what is known as the “bed type.” It is provided with a series of +wipers for toe and heel, which draw the leather simultaneously from +all directions. There can be no wrinkles at the toe or heel of shoe on +which it is properly used and the quality of work produced by it has +been very generally recognized as a distinct advance in this important +part of shoemaking. After the leather has been brought smoothly around +the toe it is held there by a little tape fastened on each side of the +toe and which is held securely in place by the surplus leather crimpled +in at this point. The surplus leather crimpled in at the heel is +forced smoothly down against the insole and held there by tacks driven +by a very ingenious hand tool in which there is a constantly renewed +supply of tacks. + +[Illustration: A MACHINE THAT FORMS AND DRIVES TACKS + +UPPER STAPLING MACHINE + +Forms small staples from wire. + +Holds shoe upper to lip of insole.] + +[Illustration: UPPER TRIMMING MACHINE. + +Trims off surplus part of shoe upper and lining.] + +In all of the lasting operations the tacks are driven but part way in, +except at the heel portion of the shoe, where they are driven through +the insole and clinched on the iron heel of the last. The tacks are +driven only part way in, in order that they may be afterward withdrawn +so as to leave the inside of the shoe perfectly smooth. In making +shoes other than Goodyear Welts, with the exception of the Goodyear +Turn Shoe, it is necessary to drive the tacks through the insole and +clinch them inside the shoe, so that the different portions of the sole +inside the shoe have clinched tacks. These are left even after the shoe +is finished. This smooth interior of the shoe is one of the essential +features of the Goodyear Welt Process. + +In the lasting operation there is naturally a surplus amount of leather +left at the toe and sometimes around the sides of the shoe, and this is +removed on the Rex Upper Trimming Machine in which a little knife cuts +away the surplus portion of the leather very smoothly and evenly, and +simultaneously a small hammer operating in connection with the knife +pounds the leather smooth along the sides and the toe of the shoe. The +shoe then passes to the Rex Pounding Machine, in which a hammer pounds +the leather and counter around the heel so that the stiff portion of +the shoe conforms exactly to the shape of the last. + +The shoe is now ready to receive the welt, which is a narrow strip of +leather that is sewed along the edge of the shoe, beginning where the +heel is placed and ending at the same spot on the opposite edge. This +welt is sewed from the inside lip of the insole, so that the needle +passes through the lip, upper and welt, uniting all three securely +and allowing the welt to protrude evenly along the edge. The needle +in making this stitch does not go inside the shoe, but passes through +only a portion of the insole, leaving the inside perfectly smooth. This +part of the work was formerly one of the most difficult and laborious +tasks in shoemaking. As it was performed entirely by hand, the drawing +of each stitch depended upon the strength and mood of the workman. +It is of course obvious that with different operators stitches were +oftentimes of different lengths and drawn at different tensions; for +human nature is much the same everywhere, and it is impossible for a +workman who has labored hard all day to draw a stitch with the same +tension at night as might have been possible in the morning. + +[Illustration: AN AUTOMATIC SEWING MACHINE WHICH NEVER TIRES + +WELT AND TURNED SHOE SEWING MACHINE + +Upper portion shows operator at machine. The lower shows formation and +location of stitch formed by this machine. + + Welt Stitch + + Welt] + +It is surprising how quickly and easily the work is done on the +Goodyear Welt Sewing Machine. This famous machine has been the +leading factor in the great revolution that has taken place in shoe +manufacturing. Its work should be carefully noted--all stitches of +equal length and measured automatically, the strong linen thread +thoroughly waxed and drawn evenly and tightly; for the machine never +tires, and it draws the thread as strongly in the evening as in the +morning. Every completed movement of the needle forms a stitch of great +strength, which holds the welt, upper and insole securely together. + +As the lasting tacks as well as the tacks which hold the insole in +place on the last were withdrawn just prior to this operation, it will +be seen that the inside of the shoe is left perfectly smooth. After +this process the surplus portions of the lip, upper and welt which +protrude beyond the stitches made by the Goodyear Welt Machine are +trimmed off by the Goodyear Inseam Trimming Machine--a most efficient +machine, in which a revolving cup-shaped knife comes in contact with +the surplus portions of the leather and trims them off very smoothly +down to the stitches. + +[Illustration: PUTTING THE GROUND CORK AND RUBBER CEMENT IN SHOES + +INSEAM TRIMMING MACHINE. + +Trims shoe upper lining and lip of insole smooth down to stitches.] + +[Illustration: WELT BEATING AND SLASHING MACHINE + +Beats welt so that it stands out evenly round edge of shoe.] + +[Illustration: PLACING SHANK AND FILLING BOTTOM. + +Workman tacks shank in place and fills bottom with ground cork and +rubber cement.] + +At this stage the shoe is passed to the Universal Welt Beater, in which +a little hammer vibrating very rapidly beats the welt so that it stands +out evenly from the side of the shoe. As the leather is bent around +the toe, it is the natural tendency of the welt to draw more tightly +at that place, and this is taken care of by a little knife which the +operator forces into operation, in the beating process, the toe is +being taken care of, and it makes a series of little cuts diagonally +along the edge of it. The insole and welt now receive a coating of +rubber cement. This cement is contained in an air-tight tank and is +applied by means of a revolving brush, which takes its supply of +cement, as required, from a can. + +In this way, an even coating of any desired thickness is given to the +insole and welt. This machine has many advantages; the cement being +closely confined in the tank, there is almost no waste in its use. +Formerly, when this was done by hand, the waste through evaporation or +lack of care on the part of the workman was very material. + +The heavy outsole of the shoe also receives at this time proper +attention. The flesh side of this sole, or the side next to the animal, +receives a coating of rubber cement, and after it has dried slightly +the operator of the Goodyear Improved Twin Sole Laying Machine takes +the work in hand. In this machine there is a rubber pad, or mould, +which has been made to conform to the curve in the sole of the shoe. +After placing the last on the spindle, which is suspended from the +machine and hangs over the rubber mould, the outsole having been +previously pressed against the bottom of the shoe, the operator by +pressing the foot lever causes this arm to descend, forcing the shoe +down into the mould, so that every portion of the sole is pressed +against the bottom of the shoe and welt. Here they are allowed to +remain for a sufficient length of time for the cement to properly set, +the operation being repeated on a duplicate part of the machine, the +operator leaving one shoe under pressure while he is preparing another. + +[Illustration: MACHINES WHICH PUT THE SOLES ON SHOES + +SOLE LAYING MACHINE. + +Presses outsole to bottom of shoe where it is held by rubber cement.] + +[Illustration: ROUNDING AND CHANNELLING MACHINE. + +Roughly rounds outsole and welt to conform to shape of last. Cuts small +channel along edge for stitches.] + +The next operation is that of trimming the sole and welt so that they +will protrude a uniform distance from the edge of the shoe. This work +is performed on the Goodyear Universal Rough Rounding Machine, which +gauges the distance exactly from the edge of the last. It is often +desired to have the edge extended further on the outside of the shoe +than it does on the inside and also that the width of the edge should +be considerably reduced in the shank of the shoe. This is taken care of +with great accuracy by the use of this machine. The operator is able +to change the width at will. By the use of this remarkable machine the +operator is also enabled to make the sole of the shoe conform exactly +to all others of similar size and design. + +[Illustration: CHANNEL OPENING MACHINE. + +Turns back lip of channel preparatory to stitching.] + +[Illustration: CHANNEL CEMENTING MACHINE. + +Coats surface of channel so it may be laid to cover stitches.] + +The surplus portion of the leather is now trimmed off on the Heel-Seat +Rounding Machine, and the channel cut by the knife on the Rough +Rounding Machine is turned up so that it leaves the channel open. This +is done by the Goodyear Universal Channel Opening Machine, in which a +little wheel, turning very rapidly, lays the lip smoothly back. + +~SEWING THE SOLE TO THE SHOE~ + +The outsole is now sewed to the welt. This operation is performed on +the Goodyear Outsole Rapid Lockstitch Machine, which is very similar in +operation to the Goodyear Welt Sewing Machine used in sewing the welt +to the shoe. The stitch, however, is finer and extends from the channel +which was cut for it to the upper side of the welt, where it shows +after the shoe has been finished. The lockstitch formed by this machine +is a most durable one. Using a thoroughly waxed thread, it holds the +outsole securely in place, even after the connecting stitches have been +worn off. This is one of the most important machines in the shoemaking +process. It is able to sew even in the narrow shank, where a machine +using a straight needle could not possibly place its stitch. + +The “Star Channel Cementing Machine--Model A” is again called into +operation for the purpose of coating with cement the inside of the +channel in which this stitch has been made. A special brush with guard +is used for this purpose, and the operation is very quickly performed +by the skilled operator. + +After this cement has been allowed to set a sufficient length of time, +the channel lip, which has previously been laid back against the sole, +is again forced into its former position and held securely in place +by rubber cement. This work is done by the Goodyear Channel Laying +Machine, in which a rapidly revolving wheel provided with a peculiar +arrangement of flanges forces back into place, securely hiding the +stitches from observation on this portion of the shoe. + +[Illustration: MACHINES WHICH PUNCH THE SOLES OF SHOES + +CHANNEL LAYING MACHINE. + +Rubs channel lip down to cover stitches.] + +[Illustration: LOOSE NAILING MACHINE + +Drives small nails which hold outsole in place at heel.] + +The next operation is that of leveling, which is performed on the +Automatic Sole Levelling Machine--one of the most interesting used +in the shoemaking process. This is a double machine provided with +two spindles, on one of which the operator places a shoe to be +levelled. It is securely held by the spindle and a toe rest, and on +the operator’s pressing a foot lever, the shoe passes automatically +beneath a vibrating roll under heavy pressure. This roll moves forward +with a vibrating motion over the sole of the shoe down into the shank, +passes back again to the toe, then cants to the right, and repeats the +operation on that side of the shoe, returning to the toe and canting to +the left, repeating the operation on that side; after which the shoe +automatically drops forward and is relieved from pressure. This rolling +motion removes every possibility of there being any unevenness in the +bottom of the shoe, and while one shoe is under pressure the operator +is preparing a second one for the operation. + +[Illustration: AUTOMATIC LEVELLING MACHINE. + +Rolls out any unevenness in soles.] + +[Illustration: HOW THE HEEL OF A SHOE IS PUT ON + + TOP LIFT + + COMPRESSED HEEL + + BEFORE OPERATION + AFTER OPERATION + + Heel Attaching + +WORK PERFORMED BY HEELING MACHINES.] + +[Illustration: AUTOMATIC HEEL LOADING AND ATTACHING MACHINE.] + +[Illustration: SLUGGING MACHINE. + +Drives small pieces of ornamental metal which protect the heel.] + +[Illustration: HEEL TRIMMING MACHINE. + +Trims rough lifts of heel to desired shape.] + +[Illustration: HEEL BREASTING MACHINE. + +Cuts the breast of the heel to correct angle and curve.] + +[Illustration: EDGE TRIMMING MACHINE. + +Trims edge of outsole smoothly.] + +[Illustration: A LUMP OF PULP. + +Paper such as found in this book is made from trunks and limbs of trees. + +The use of good fibers in book paper is a guarantee of quality and +durability. The above illustration represents a lump of this pulp +prepared for the beaters.] + + + + +How the Paper in this Book is Made + + +Where Does Paper Come From? + +Egyptians were the first people to make what would today be called +paper. They made it from a plant called papyrus and that is where the +name comes from. + +This plant is a species of reed. The Egyptians took stalks of reed cut +into as thin slices as they could, laid them side by side; then they +arranged another layer on top with the slices the other way and put +this in a press. When dried and rubbed until smooth, it made a kind of +paper, which could be written upon. + +One of the first substances used for making the kind of paper we have +today was cotton. Paper was made from cotton about 1100 A. D. From this +thin cotton paper our present papers are a development, i.e., paper +today is largely made of vegetable fibers. Vegetable fibers consist +mostly of cellulose surrounded by other things which hold the short +vegetable fibers together. + +The fibers best adapted for making paper are those of the cotton and +flax plants, and while the uses of paper were few, no other material +was needed when it was once learned that cotton and linen fibers would +do for making paper. All we had to do was to save all the old rags and +sell them to the paper man. + +In making paper from rags, the rags were allowed to rot to remove the +substances that incrust the cellulose, and then beaten into a pulp, +to which a large quantity of water was added. This pulp was put into +a sieve, until the greater part of the water had been drained off by +shaking, and the fibers remaining formed a thin layer on the bottom of +the sieve. This layer of fiber was put into a pile with other similar +layers, and the whole pile was placed under a press, where more of +the water was removed. When they were dry, we had a very fair kind of +paper which was, however, not much better than blotting paper and could +not be written on with ink because it was loose in texture and very +absorbent. + +To give it good writing surface it was necessary to fill the pores. +This was done by sizing which gave the paper great firmness. Paper was +sized by drawing the layers of paper through a solution of alum and +glue, or some similar substances, and then drying them, then finally +passed between highly polished rollers to iron it. This gave it the +necessary smooth hard surface. + +In the modern method of making rag paper by machinery, the rags are +boiled with caustic soda, which separates the cellulose fibers, and +placed in a machine in which rollers set with knives tear the rags +to pieces and mix them with water to form a pulp. This is called a +breaker. The pulp is then bleached with chloride of lime, and is passed +on to the sizing machine. This machine mixes the pulp with alum and +with a kind of soap, made from suitable resins which serves the purpose +better than glue. + +[Illustration: NOT A WOOD YARD BUT THE OUTSIDE OF A PAPER MILL. + +This shows the great piles of trunks and limbs of trees near a wood +pulp paper mill used in making paper for newspapers, books, magazines, +etc.] + + +How Is the Water Mark Put Into Paper? + +The pulp, which is now ready to be made into paper, is poured out upon +an endless cloth made of fine brass wire. This cloth travels constantly +in one direction, by means of rollers, and is given at the same time +a sort of vibratory motion, to cause the paper fibers to become more +closely felted together. On the wire cloth web are usually woven words, +or designs, in wire, that rise above the rest of the surface. These +are transferred to the paper, and are called water marks. The machine +then winds the finished paper into rolls, so that it may be handled +conveniently. + +~HOW PAPER IS NOW MADE FROM WOOD~ + +During the past few years the uses for paper have increased so greatly +that there have not been enough rags available to meet the demand for +material, and a successful effort was made to find other material from +which paper could be made. Many fibers were tried before it was found +that wood pulp could be used. Straw and esparto grass, a plant that +grows wild in North America, were found to yield cellulose having the +desired qualities and were used to some extent. But the problem was +solved when it was learned that pulp made from trunks and limbs of +trees would serve even then. At first the powder formed by grinding up +logs was used, but the paper produced was not strong, and could be used +for very few purposes. + +[Illustration: GREAT FORESTS TURNED INTO PAPER + +PAPER TREES. + +This picture shows the trees as they grow in the woods. These trees are +good for making paper. Your morning paper, may some morning be printed +on what is left of one of these trees.] + +It was discovered finally that if wood shavings were boiled in strong +solutions of caustic soda, in receptacles that would withstand very +high pressure, the wood fibers were separated, and a very good quality +of cellulose for paper manufacture produced, provided it was bleached +before being made into paper, and most of our paper to-day is, +therefore, made of wood. + +Later on this process gave way to the sulphite process. In the sulphite +process, a solution of sulphite of lime is used. Acid sulphite of lime +results when the fumes from burning sulphur are passed through chimneys +filled with lime. By this process the separation of the fibers and the +bleaching are done at the same time and an even whiter paper making +material is obtained. + +The sulphite process is now used almost exclusively in making paper +from wood. + +[Illustration: GRINDING ROOM. + +In this picture we see how the trees are first cut into smaller chunks +before being reduced to chips for making pulp.] + +The discovery of the process of making paper from wood has led to the +use of paper for many purposes for which it could otherwise never have +been used. The wood pulp is also used in the form of papier-mâché, a +tough, plastic substance, which is made by mixing glue with it, or by +pressing together a number of layers of paper having glue between. +Papier-mâché can easily be molded into almost any form, and after +drying forms a very tough substance and one that will stand rough +usage. It has been employed for making dishes, water baskets and +utensils of many other kinds, for making the matrices for and from +electrotype plates, for car wheels, and many other purposes. + +[Illustration: WHERE THE INGREDIENTS FOR MAKING PAPER ARE MIXED + +MIXING ROOM. + +The wood fiber must be mixed with other ingredients when paper is made +from it. This shows a corner of the large electro-chemical department +for the production of bleach and soda used in the preparation of rag +and wood fibres.] + +[Illustration: THE WATER SUPPLY. + +A good deal of water is needed in making paper. From twelve to fifteen +million gallons daily are drawn from the river and filtered through +this plant in Maine; clean paper of bright color being dependent upon +the use of pure water.] + +[Illustration: BEATING THE INGREDIENTS FOR MAKING PULP + +BEATER ROOM. + +The ingredients for making paper are first mixed thoroughly in machines +called “beaters” before going to the paper making machines. The +operation of beating is one of the most important in paper making.] + +[Illustration: THE PAPER COMING OFF IN ROLLS. + +As the paper progresses through the machines, it passes over a long +series of heated cylinders, drying and hardening the stock until it +reaches the finished end. This illustration shows a web 135 inches +wide being cut into two rolls. The air pressure in the machine room is +slightly greater than the atmospheric pressure outside, preventing dust +from entering.] + +[Illustration: GREAT PAPER-MAKING MACHINES IN OPERATION + +PAPER MAKING MACHINES. + +In the foreground is the so-called wet end showing the vats in which +the liquid pulp, about 98 per cent water, is pumped. It is screened and +then flows on to an endless wire web beyond, where the free water is +taken out by drainage and by suction boxes.] + +[Illustration: PUTTING THE PRINTING SURFACE ON THE PAPER + +PAPER STOCK. + +A large amount of stock of paper mills. This paper is seasoned by +holding it in stock and will be later given such surface as is called +for.] + +[Illustration: COATING MACHINES. + +Where the paper passes through a bath of coating mixture to a long +drying gallery at the end of which it is rewound preparatory to being +given the highly finished surface on the calendaring machine.] + +[Illustration: A section of Finishing Room department where paper is +passed through alternating compressed fiber and steel rolls giving +it the surface required for different classes of printing. The paper +on which the Book of Wonders is printed has a highly finished smooth +surface so that the pictures will come out clear.] + +[Illustration: WHERE THE PAPER IS CUT IN SHEETS + +The finished rolls of stock pass through rotary cutters which produce +the sheets of various required sizes. The paper in the Book of Wonders +was cut in sheets 41x55 inches, thus making it possible to print 32 +pages on each side of each sheet.] + +[Illustration: Rotary Boiler for cooking rags or wood in making pulp +for use in manufacture of paper.] + + Illustrations showing manufacture of paper by courtesy of S. D. + Warren & Co. + +[Illustration: HOW THE PRINTED TYPE OF THIS BOOK WAS SET + +This picture shows the wonderful Linotype machine by which the type +of this book was “set,” as the printers say. The men who operate the +machine are compositors. Originally the type matter of books was set +by hand and the compositor composed in type what the author of the +book had written. By pressing down on the keys which you see in the +picture, the compositor sets the words in lines of metal. This machine +is almost human. By touching the proper keys, the operator assembles a +line of matrices the details of which are explained in another picture, +and after this is done the machine automatically casts a slug from +them, turns and delivers a slug into a galley ready for use and finally +distributes the matrices back into their respective channels in the +magazine, where they are ready to be called down again, by the touch of +the key button. The latest model linotype has four magazines and can be +equipped with matrices which when assembled will cast lines in from six +to twelve different sizes and styles of type. + +The assembling mechanism is the only part of the linotype where the +human mind is applied to the working of the machine. It is necessary +for the eye to read what is to be printed, and the mind, through the +medium of the fingers, to translate this into assembled lines of +matrices; after that the machine acts automatically.] + +[Illustration: THE LINOTYPE—FOUR MACHINES IN ONE + +The keyboard is made up of 90 keys, which act directly on the matrices +in their channels in the magazine. The slightest touch on the +keybuttons releases the matrix, which drops to the assembler belt and +is carried swiftly to the assembler. When a word is assembled, the +spaceband key is touched and a spaceband drops into the assembler. +When the necessary matrices and spacebands to fill the line have been +assembled, the operator raises the assembler by pressing a lever on the +side of the keyboard. When the assembler reaches its highest point it +automatically starts the machine and the matrices are transferred to +the casting position. + +This illustration shows the manner in which matrices are constantly +circulated in the Linotype. From the magazine they are carried to the +assembler, then passed to the mold, where the line is cast, and from +the mold after casting they are raised to the top of the machine and +redistributed to their proper channels in the magazine. + +The Linotype is sometimes called a typesetting machine, but this is not +correct: it does not set type. It is a substitute for typesetting. It +is strictly speaking a composing machine, as it does composition but +its product is not set type, but solid slugs in the form of lines of +type with the printing face cast on the edge. + +It is in reality four machines so arranged that they work together in +harmony--the magazine, the assembling mechanism, the casting mechanism +and the distributing mechanism. The magazine is at the top of the +machine sloping to the front at an angle of about 31 degrees, and +consists of two brass plates placed together with a space of about +five-eighths of an inch between. The two inner surfaces are cut with 92 +grooves or channels running the up and down way of the magazine, for +carrying the matrices. The matrices slide down these channels on edge, +with the face or punched edge down, and the V-end extending toward the +upper part of the magazine. Each of these channels will hold twenty +matrices.] + +[Illustration: LITTLE PIECES OF BRASS WHICH PRODUCE SOLID TYPE + +ONE-LETTER AND TWO-LETTER MATRICES. + +Linotype matrices are made of brass. In the edge of each matrix is +either one or two letters or characters in intaglio. The thickness of +the individual matrices is dependent on the width of the character. +By an ingenious arrangement either one-letter or two-letter matrices +can be used in the same machine, and either character on a two-letter +matrix can be used at will. + +The two-letter matrix bears two characters, one above the other, one +of which may be a Roman face and the other an italic, small capital, +or black face. If a line is to be composed partly of the Roman face, +which is in the upper position on the matrix, and partly of the other +face, which is in the lower position, this is accomplished by means of +a slide on the assembler operated by a small lever. + +When the lower characters on the matrices are required, the slide +is shifted and the matrices are arrested at a higher level, so that +the lower characters align with the upper characters of the other +matrices in the assembler. When the slide is withdrawn the matrices are +assembled at the lower level. By means of this simple contrivance, a +line may be composed partly of one face, partly of the other face, or +entirely of either face.] + +[Illustration: THIS SHOWS HOW THE HEADINGS ARE MADE IN CAPITALS OF +DIFFERENT TYPE. + +Linotypes are guaranteed to be capable of setting above 5000 ems of +6 point per hour, and this output is widely obtained in commercial +printing offices with first class operators. When a compositor speaks +of the amount of type he sets per hour or day he speaks of “ems.” A +column of type matter is so many “ems” wide. The term “em” means the +square of the particular size of type that is being set. Thus if a +column is said to be 13 ems wide it means that an em quad or square, +could be set 13 times in the width of the column. Type is graded +according to size by points. Machine type for book work runs from 5 +points to 12 points. A point is one seventy-second of an inch, that is, +there are 72 points to an inch. This guarantee, however, by no means +indicates the limit of speed at which the machine can be operated, as +evidenced by records of 10,000 to 11,000 ems per hour maintained for an +entire day. The rapidity of the Linotype is limited only by the ability +of the operator to manipulate the keys, and the extreme capacity of the +machine has never yet been attained.] + +[Illustration: HOW THE LINOTYPE MAKES SOLID TYPE + +SECTIONAL VIEW OF MAGAZINE SHOWING CHANNEL FULL OF MATRICES. + +This picture shows the machine with part of the magazine top and +side removed. We can thus see how the matrices are arranged in their +respective grooves in the magazine. When one of the keys of the +keyboard is pressed down the first matrix in the corresponding grove in +the magazine escapes and drops upon a conveyor belt and is carried in +its proper order to an assembler, which answers much the same purpose +as a printer’s stick. The correct spacing or justification of the line +of matrices is accomplished by means of spacebands, which are assembled +automatically between the words in the line by the touch of a lever at +the left of the keyboard.] + +[Illustration: LINOTYPE SLUGS. + +Instead of producing single type characters, the Linotype machine casts +metal bars, or slugs, of any length desired up to 36 ems, each complete +in one piece and having on the upper edge, properly justified, the +characters to print a line. These slugs are automatically assembled +in proper order as they are delivered from the machine, when they are +immediately available either for printing from direct or for making +electrotype or stereotype plates. They answer the same purpose and are +used in the same manner as composed type matter.] + +[Illustration: CASTING THE SLUGS OF SOLID METAL + +LINE OF MATRICES BEING LIFTED TO DISTRIBUTOR + +After the slug has been cast, the matrices are carried up to the second +transfer position, where they are pushed to the right, and the teeth in +the V at the top of the matrices engage the grooves in the distributor +bar of the second elevator, which descends from the distributor box at +the same time that the matrices rise to the second transfer position. +The second elevator then rises toward the distributor box, taking the +matrices with it, but leaving the spacebands; these are then pushed to +the right and slide into the spaceband box, to be used again. + +As the second elevator rises toward the distributor box with its load +of matrices, the distributor shifter lever moves to the left until +the elevator head has reached its place by the distributor box. It +then moves back to the right and pushes the matrices off the second +elevator distributor bar into the distributor box, where they meet the +“matrix lift” and are lifted, one at a time, to the distributor screws +and distributor bar proper. The teeth in the matrix and the grooves in +the bar are so arranged that when a matrix arrives at a point directly +over the channel in which it belongs, it “lets go” and drops into its +channel. + +If, however, there is a matrix in the line which was not designed to +drop into one of the channels operated from the keyboard, it will be +carried clear across the distributor bar and dropped into the last +channel, and from there it will find its way to the sorts box.] + +[Illustration: SECTIONAL VIEW OF METAL POT WITH LINE OF MATRICES IN +POSITION BEFORE THE MOLD + +The casting mechanism consists of the metal pot, mold disk, mold, +ejector, and trimming knives. The illustration shows a cross-section +of the metal pot, mold disk, and mold, with a line of matrices in the +casting position. When the line of matrices leaves the assembler, +they pass to a position in front of the mold disk. The disk makes a +one-quarter turn to the left, which brings the mold from the ejecting +position, where it stands while the machine is at rest, to the casting +position. It then advances until the face of the mold comes in contact +with the matrices. The metal pot advances until the pot mouthpiece +comes in contact with the back of the mold; at this point the pump +plunger descends and forces the metal into the mold and against the +matrices. The pot then recedes, the mold disk withdraws from the +matrices and makes three-fourths of a revolution to the left, stopping +in the ejecting position, from which it started. The slug is ejected +and assembled in the galley. + +During the last revolution of the disk the bottom of the slug is +trimmed off, and in the process of ejection the sides of the slug are +trimmed, so that when it drops in the galley the slug is a perfect line +of type, ready for the form.] + +[Illustration: HOW THE PRINTED PART OF A BOOK LOOKS AT FIRST + +As the slugs of type, each of which represents a line, come from the +linotype machine, they are arranged in order in a brass holder the +width of the line of type, called a “galley.” This holder is about +twenty inches long. As soon as it is filled one of the men in the +typesetting office takes it to a proof press where he makes a rough +impression of it. He runs an ink covered roller over the top of the +slugs, lays a piece of blank paper on it and then either runs another +roller over it or puts it in a hand press and secures an impression of +the type just as it is. This is called making a “galley proof.” + +The galley proof is then sent to the proof-reader who reads it +carefully and indicates such errors in setting as appear and must be +changed. Before correcting the actual type, however, the composing +room sends the galley proof to the one who is publishing the book. +The publisher also reads the proof over carefully and, if he does not +wish to change any of the wording, he sends it back to the composing +room with his “O. K.” attached in writing. If he wishes to change +the wording, he does so and the galley proof is then returned to the +composing room marked “O. K. after corrections and changes are made.” + +The linotype operator then makes whatever changes are desired or +necessary by setting new lines where mistakes or changes occur. If +there is only one wrong letter in a line, he must reset the whole line +as the machine, as you remember, only turns out solid lines of type. A +revised proof is then sent to the publishing office and, if no further +changes are to be made, he gives instructions to have the “galley” made +up into pages. How the pages are made up is shown in the next picture.] + +[Illustration: HOW THE PAGES OF A BOOK ARE MADE UP + +When the revised proofs come back from the publisher ready to be made +into pages, the publisher has marked on same what pictures are to go on +the pages of the “make up” as this is called. The compositor then picks +out the pictures in the form of cuts which are to go on the different +pages and puts them in the page first. He then arranges the type matter +from the galley proof around, above or below the pictures, puts in the +proper headings and takes a “final proof” of how the pages are arranged +to look. If this is satisfactory the publisher puts a “final O. K.” +on the proof in writing and the page is ready to be printed. Thus the +book is made up page by page. No page is printed without the O. K. of +the publisher and so, if there are any errors still in the page, the +publisher is responsible.] + +[Illustration: HOW THIS BOOK IS PRINTED + +PRINTING THE BOOK OF WONDERS + +This picture shows the pages of the Book of Wonders being printed. +Thirty-two pages are printed on each side of a sheet of paper at +one time. A printing office is a busy place as can be seen from the +picture. As soon as the ink is dry on the printed sheets they are taken +to the bindery where they are folded and sewed ready to have the covers +put on.] + +[Illustration: HOW THE BOOK OF WONDERS IS BOUND + +When the printed sheets are received in the bindery they are fed into +a folding machine which is shown here. A sheet of 64 pages is folded +and cut and delivered in four sections of 16 pages each ready to be +gathered.] + +[Illustration: Here we see a machine which takes the folded sections of +16 pages each, which are called “signatures,” and sorts them, dropping +them into compartments in order, so that each compartment finally +contains the printed matter for one book all arranged in the order +which it will be bound.] + + Courtesy of the J. F. Tapley Co. New York. + +[Illustration: SEWING THE PAGES OF THE BOOK OF WONDERS + +Here we see the girls at work operating the sewing machines which sew +the sections together at the back side of the book.] + +[Illustration: The men in this picture are making the backs of the +books round and preparing them for the putting on of covers.] + + Courtesy of the J. F. Tapley Co., New York. + +[Illustration: THE BOOK OF WONDERS IS READY TO READ + +In this picture we see the “case makers” at work making the covers on +which the actual book is bound.] + +[Illustration: The book is now “bound” by having the covers put on and +is ready for distribution.] + + Courtesy of the J. F. Tapley Co., New York. + + +How Is Photo Engraving Done? + +[Illustration: This cut shows a section of a photo-engraving screen +enlarged, illustrating the squares above-mentioned. In reality it would +take from 100 to 400 of these dots to make an inch, according to the +fineness of screen.] + +~HOW THE PICTURES IN THIS BOOK ARE MADE~ + +The first step is the making of the halftone negative which differs +from an ordinary negative in being made up of different sized dots +instead of shades of gray. This result is obtained by photographing the +picture through a halftone screen consisting of two pieces of glass, +ruled with black lines and cemented together so the lines cross at +right angles and leave small squares of clear glass. + +The effect of making the negative in this way is to represent the +different shades from black to white by large or small dots. Wet plate +photography is usually used in this process because the film is thinner +and more intensely black besides being cheaper than dry plates. + +[Illustration: + + New Process Engraving Co. + +This cut shows a portion of a halftone cut enlarged so that the dots +can be seen very plainly.] + +Having made the negative the next step is to make a printing plate +from it. To do this, a piece of metal, copper if the work is fine, and +zinc for coarser work, is coated with a solution which is sensative to +light, fish glue is commonly used to which is added a small amount of +ammonium bichromate. The metal being coated and dried, it is put in +a very strong frame with the negative and squeezed together so that +they are in perfect contact. A powerful light is now directed upon the +negative with the metal behind it, the result being that wherever the +light goes through the white spaces in the negative, the coating on the +metal is rendered insoluble. Where the dots on the negative are, the +light is unable to get at the coating so that when the metal is removed +from the frame and thoroughly washed this part of the coating washes +away, leaving the part which the light got at attached to the metal. +This is now heated until the enamel, as the coating is called, turns +dark brown and the picture can be easily seen. + +The picture is now on the metal but it must be made to stand out in +relief before it can be used for printing from, so it is put in a bath +of acid which eats away that part of the metal left uncovered by the +washing away of the coating and this leaves the dots which make up +the picture standing up in relief. A roller covered with very thick +paste-like ink is now rolled over the picture, or cut as it is now +called, and when a piece of paper is pressed against the ink covered +cut each little dot leaves a mark of ink on the paper the total making +up the picture as we see it. + +There are many more wonderful things connected with the making of cuts +such as the routing machine which has a tool that revolves so fast +that it turns around 300 times while the clock ticks once, and other +machines which cut hard metal as easily as you can cut a potato with a +knife. + +Colored pictures are also made by the process outlined above. The +picture is photographed three times with a different colored piece of +glass in front of the lens, the result being three negatives, one of +which has all the blue, one all the red and the other all the yellow +in the picture. By making cuts from each negative and printing them +on top of one another in yellow, red, and blue, the original picture +is reproduced in all its colors. This is how all our pretty magazine +covers are made. + + + + +ACKNOWLEDGMENT + + +The Editors of the Book of Wonders make acknowledgment herewith to the +following. All mentioned have been a great assistance in making the +book not only possible but authentic: + + Spencerian Pen Co. + Eastman Kodak Co. + American Telephone & Telegraph Co. + Remington Arms Co. + Bethlehem Steel Co. + American Portland Cement Manufacturers Assn. + Brainerd & Armstrong Silk Co. + Corticelli Silk Co. + Curtiss Aeroplane Co. + U. S. Beet Sugar Industry. + Hartford Carpet Co. + Haynes Automobile Co. + Jacobs & Davis, Engineers. + Pennsylvania Railroad Co. + Endicott, Johnson & Co. + United Shoe Machinery Co. + Sherwin-Williams Co. + Pittsburgh Plate Glass Co. + The Colliery Engineer. + Lake Torpedo Boat Co. + Western Union Telegraph Co. + New York Edison Co. + Westinghouse Lamp Co. + Consolidated Gas, Electric Light and Power Co. of Baltimore. + Browning Engineering Co. + The White Star Line. + Marconi Wireless Co. + Plymouth Cordage Co. + American Woolen Co. + The Vitagraph Co. + The B. F. Goodrich Co. + The Goodyear Rubber and Tire Co. + The Lexington Chocolate Co. + The Hecker-Jones Milling Co. + The White Oak Mills. + The H. C. White Company. + A. I. Root Company. + Kohler & Campbell. + Browne & Howell Co. + P. & F. Corbin. + Otis Elevator Co. + Scientific American. + Joseph Dixon Crucible Co. + Homer W. Laughlin Co. + S. D. Warren & Co. + C. B. Cottrell & Sons Co. + Mergenthaler Linotype Co. + J. F. Tapley & Co. + New Process Engraving Co. + Mutual Film Corporation. + Tobacco Trade Journal Co. + McClure’s Magazine. + James Arthur. + Seth Thomas. + American Locomotive Co. + New York Central Railroad Co. + Columbia Rope Co. + Carl Werner. + National Wool Growers Assn. + + + + +INDEX + + + =Acid=, carbonic, what it is, 509 + + =Aerial=, on ship, (illus.), 455 + + =Aeroplanes=, English Channel crossing (illus.), 132 + Curtiss biplane (illus.), 131 + first demonstrations of, 130 + first flight in Europe, 129 + first man-carrying (illus.), 128 + first successful (illus.), 126 + gas motors used in, 130 + gliding, 137 + greatest present value of, 136 + records of, 131 + red wing (illus.), 131 + what two brothers accomplished for, 130 + Wright Bros.’ inventions, 130 + + =Age=, why do we, 196 + + =Air=, does it move with the earth? 400 + does it weigh anything? 398 + dust in, 38 + extend, how far does, 243 + + =Airlocks=, description of in tunnel building, 213 + + =Ammunition=, first invention of, 40 + fixed, 47 + in prehistoric times, 40 + + =Animals=, can they think? 194 + is man an, 180 + that leap greatest distance, 122 + which foretell weather, 240 + + =Anthracite seams= (illus.), 260 + + =Aqueduct= (illus.), 505 + + =Are= matches poisonous, 294 + + =Armor=, in the Middle Ages, 44 + + =Army=, wireless in the, 448-451 + + =Are= there two sides to the rainbow? 254 + + =Arrow=, what causes it to fly? 408 + + =At= what point does water boil? 220 + + =At= what rate does thought travel? 242 + + =Australian Ballot=, where first used, 122 + + =Automobile= (illus.), axle, location of, 186 + beginning of, 183 + carburetor, location of, 184 + carburetor, use of, 184 + chassis, complete, 188 + cog-wheels, use of, 183 + cog-wheels, location of (illus.), 183 + crankcase, location of (illus.), 183 + cylinder, location of (illus.), 184 + drive shaft, location of (illus.), 187 + electric generator, use of, 185 + exhaust, 184 + fenders, location of, 188 + fenders, use of, 188 + finished car (illus.), 189 + first American (illus.), 189 + fly-wheel, location of (illus.), 183 + fly-wheel, use of, 183 + frame (illus.), 186 + gasoline, what it does, 183 + gasoline tank, location of, 187 + gears, location of (illus.), 183 + gears, use of, 183 + heart of (illus.), 184 + how improved, 190 + magneto, location of, 185 + magneto, use of, 185 + marvellous growth of twenty years, 189 + modern power plant complete, 190 + oil pan, use of, 184 + oil pump, location of, 184 + piston, location of (illus.), 183 + piston, use of, 183 + power plant, an (illus.), 185 + radiator, location of (illus.), 188 + radiator, use of, 188 + ready for the wheels, 187 + second stage of construction (illus.), 186 + self-starter, location of, 185 + self starter, use of, 185 + Smithsonian exhibit of complete power plant, 190 + springs, location of (illus.), 186 + springs, use of, 186 + steering gear, location of (illus.), 187 + street scene 20 years ago, 189 + transmission, location of, 186 + tire pump, use of, 185 + tires, how made, 382 + transmission, use of, 186 + water pump, location of, 185 + water pump, use of, 185 + what the completed chassis looks like (illus.), 188 + + =Bacon, Roger=, discoverer of gunpowder, 44 + + =Balance=, effect of sunlight on, 37 + + =Baldness=, chief course of, 143 + why some people are, 143 + + =Ball=, why it bounces, 63 + bearings, what they are, 180 + + =Balloon=, what keeps it up, 199 + why it goes up, 199 + + =Ballot=, when first used, 122 + Australian, where first used, 122 + + =Bearings, Ball=, what they are, 180 + + =Bee=, how it lives, 336 + why it has a sting, 336 + + =Bell, Alexander Graham= (illus.), 70 + first telephone, 72 + + =Bend=, why things, 62 + + =Biplanes=, Curtiss (illus.), 131 + in flight, Curtiss (illus.), 136 + + =Birds=, how do they find the old home? 408 + how they learn to fly, 178 + how they find their way, 407 + reproduction of life in, 179 + why do they sing? 408 + + =Birds’ Eggs=, why different colors, 233 + + =Blasting= gelatin, definition of, 206 + + =Bleriot, M.=, first European flights, 129 + + =Blotter=, capillary attraction of, 18 + how it takes up ink, 18 + + =Blush=, why do we, 194 + + =Boat=, how it can sail under water, 269 + hydroplane of submarine, 270 + inside of a submarine (illus.), 272 + + =Bodies=, swiftest moving, 25 + + =Boiling= point of water, 220 + what makes water, 220 + + =Boring mill= (illus.), 56 + + =Bottles=, gurgle in, 63 + + =Bounce=, why a ball will, 63 + + =Bow=, long (illus.), 42 + + =Bow-and-Arrow=, invention of, 43 + + =Boxes=, match, how made, 294 + + =Brazil, Emperor of=, receives first words over telephone, 74 + + =Bread=, how flour is made, 462 + difference in Graham and whole wheat, 461 + grinding wheat (illus.), 464 + harvesting wheat, 460 + loaves of world (illus.), 459 + origin and meaning of, 460 + purifying machine (illus.), 463 + separating fibre germs (illus.), 463 + wheat conditioning (illus.), 462 + when wheat was first used in making, 461 + where it comes from, 460 + why so important, 460 + + =Break=, why things, 62 + + =Breech=, of a big gun, 53 + + =Breech-loaders= in Civil War, 48 + in rifle, 47 + + =Brush=, in writing, invention of, 13 + in writing (illus.), 13 + + =Bullets=, cupro-nickel used in, 50 + grading of, 51 + weighing of (illus.), 49 + + =Buildings=, concrete, how made (illus.), 100 + + =Buttons=, on sleeves, 64 + + =Building=, tallest in the world (illus.), 395-508 + what holds it up? 496 + + =Building foundations=, construction of, 496 + compressed air, use of (illus.), 500 + cutting piles with a hot flame (illus.), 498 + driving steel piles, 496 + piles filled with concrete (illus.), 499 + piles, length of, 497 + piles, sinking of (illus.), 497 + use of oxyacetylene, 498 + + =Cable, laying= armoring machine (illus.), 437 + arrived on other side, 433 + bulge (illus.), 437 + gear-paying-out (illus.), 431 + Great Eastern, the, 434, 437 + landing of (illus.), 433 + machinery on cable ship (illus.), 431 + paying-out machine (illus.), 431 + shore end of (illus.), 429 + storing of, aboard ship (illus.), 430 + what they look like when cut in two (illus.), 428 + + =Cable, ocean=, Continental Morse Code, 438 + how dropped (illus.), 432 + how repaired (illus.), 435 + inventor of, 434 + laid, how, 429 + man who made it possible, 434 + pioneers of, 434 + signals as received (illus.), 438 + what is it made of, 429 + + =Cable, repairing=, grapnels (illus.), 435 + how repaired, 435 + on rocky shore, (illus.), 438 + powerful engines used (illus.), 436 + splicing of (illus.), 436 + + =Cable, service=, map of Trans-Atlantic, 439 + + =Cable, vault=, of telephone (illus.), 67 + + =Cabriolet=, 122 + + =Cacao, beans=, bags of (illus.), 388 + how cured, 392 + nibs, 392 + + =Cacao=, flaked, how made, 392 + how gathered, 391 + pods, how gathered, 391 + free, discovery of, 388 + and chocolate, difference between, 389 + + =Cackling=, why a hen, 233 + + =Calibre= of a gun, 53 + + =Calico=, name, where from, 123 + + =Camera=, 22 + first moving picture, 375 + + =Can= a bee sting? 536 + + =Can= animals think? 194 + + =Candles=, did they come before lamps? 294 + why it burns, 21 + why it gives light, 21 + why you can blow out, 21-36 + when introduced, 296 + + =Candy=, why do children like? 409 + why does eating candy make some people fat? 409 + + =Carbon=, 352 + + =Carbonate of Soda=, used in developing, 23 + + =Carburetor=, in gas engine, 184 + + =Carpets=, carding machine (illus.), 170 + dyeing the yarn, (illus.), 170 + examining and repairing (illus.), 173 + how yarn is dyed, 170 + manufacture of (illus.), 169 + modern, how made, 169 + packing for shipment (illus.), 173 + processes, 169-170-171, 173 + stamping designs, 173 + view of factory (illus.), 172 + weaving, by machine (illus.), 171 + wool, packing machine (illus.), 169 + wool sorting, 170 + + =Cartridges=, invention of, 48 + types of (illus.), 49 + + =Cave=, man who invented ammunition, 40 + + =Cement=, alumina in, 95 + amount used in United States, 95 + arch, 95 + bagging (illus.), 99 + bridges, 95 + bucket (illus.), 97 + burned (illus.), 98 + calcined (illus.), 98 + clay in, 95 + crusher (illus.), 97 + dams, 95 + fireproof, 95 + grinders (illus.), 98 + industry, 95 + in water, 95 + kiln (illus.), 98 + lime in, 95 + machine (illus.), 97 + marl in, 95 + mill (illus.), 96-98 + mixing (illus.), 99 + mortar, 99 + on farms, 95 + origin, 95 + plastic, 95 + Portland, 95 + powder (illus.), 98 + quarry (illus.), 96 + reinforced, 95 + rock (illus.), 95-97 + sewers, 95 + shale in, 95 + shovel (illus.), 96 + sidewalks, 95 + silica in, 95 + strength of, 95 + subways, 95 + tunnels, 95 + walls, 95 + what is it, 95 + what made of, 95 + what used for, 95 + weighing (illus.), 99 + where obtained (illus.), 97 + + =Chalk=, where it comes from, 18 + + =Chattering=, why do my teeth, 218 + + =China-making=, blungers, 404 + clay, in making dishes, 405 + decorating cups (illus.), 404-406 + dishes, how shaped, 405 + glazing plates (illus.), 404 + grinders (illus.), 404 + how the dishes are shaped, 405 + molding (illus.), 405 + pressing water from clay (illus.), 405 + pulverizing materials, 404 + pulverizing mill (illus.), 404 + saggers (illus.), 406 + taking the dishes from kiln (illus.), 406 + + =Chinese=, probable discovers of gun powder, 44 + + =Chocolate=, broma, what it is, 390 + cacao beans (illus.), 388 + cacao pods, (illus.), 391 + cacao tree, discovery of, 388 + cocoa butter, 390 + cocoa mill (illus.), 390 + cocoa roaster (illus.), 390 + cocoa shells, 390 + cracking mill, 389 + cream mixing (illus.), 393 + difference between and cacao, 394 + dipping department, 394 + finisher (illus.), 392 + flaked cocoa, 392 + heating machine (illus.), 393 + how are chocolate candies made? 394 + how made, 392 + making, 393 + milk, how made, 394 + mill (illus.), 392 + mixer (illus.), 393 + shell separator (illus.), 389 + what cocoa butter is, 390 + wrapping individual, 394 + + =Cigars=, how they are made, 517 + + =Clay=, what is, 495 + + =Circles=, tendency to walk in, 91 + + =Clinking= glasses, how it originated? 232 + + =Clock=, age of, 319 + largest in the world (illus.), 321 + machinery which runs a big (illus.), 322 + in Independence Hall (illus.), 323 + in New York City Hall, 323 + + =Cloth=, beaming (illus.), 89 + Burling (illus.), 88 + Burr picker, 87 + chloride of aluminum in making, 98 + English cap spinning (illus.), 89 + finished, ready for market (illus.), 90 + finish perching (illus.), 90 + fulling (illus.), 90 + how made from wool, 85 + how made perfect, 83 + how woolen is dyed, 87 + mending perching (illus.), 88 + napping, 89 + piece dyeing (illus.), 90 + ring twisting (illus.), 89 + sulphuric acid solution in making, 87 + teasel, 89 + weaving and scouring (illus.), 88 + web, 86 + woolen mule spinning (illus.), 89 + worsted carding (illus.), 85 + yarn inspecting (illus.), 89 + + =Clothes=, cost of wool in a suit of, 83 + of wool, 80 + wool in one suit of, 83 + + =Coal=, anthracite, 257, 258 + anthracite seams (illus.), 260 + breaker (illus.), 257 + cars ready to go to surface (illus.), 260 + dangers to the miners, 262 + electric cap lamp (illus.), 264 + firedamp, 262 + gas illuminating from, 299 + gases, 262 + history of the safety lamp (illus.), 263 + how the miners loosen the coal (illus.), 261 + how the slate pickers work (illus.), 259 + lamp which saves many lives, 263 + man who invented the safety lamp, 264 + mine workers that never see day light, 258 + mules and their drivers (illus.), 258 + peat, 262 + safety lamp and firedamp, 262 + seams (illus.), 260 + shaft gate (illus.), 260 + slate pickers (illus.), 259 + soft, 259 + spiral slate pickers (illus.), 259 + stable underground (illus.), 258 + undercutting with compressed air machines (illus.), 261 + undercutting with pick (illus.), 261 + + =Cocoa=, see Cacao + + =Cocoon=, description of, 115 + completed (illus.), 116 + from which moths have emerged (illus.), 117 + how silk is reeled from, 118 + moths emerging from (illus.), 117 + number required to one pound of silk, 117 + silkworm beginning of (illus.), 116 + silkworm, preparing for making of (illus.), 116 + + =Coins=, gold, 266 + in glass of water, 38 + silver, 266 + + =Cohesion=, definition of, 219, 220 + + =Cold=, why some things are, 144 + + =Color=, exposed to light rays, 36 + in paint, 229 + what it is, 123 + + =Colors=, different in birds’ eggs, 233 + in sunset, cause of, 253 + + =Color=, of rainbow, 253 + red, why it makes a bull angry, 490 + + =Columbus=, brought first sheep to America, 80 + + =Comb honey=, development of (illus.), 529 + + =Compounds=, compared with elements, 349 + + =Compressed air=, method in building tunnels, 211 + + =Concrete=, buildings (illus.), 100 + construction (illus.), 100 + decay, 101 + engineering, 102 + forms (illus.), 100 + houses (illus.), 101 + loads (illus.), 100 + mold, 101 + ornamental (illus.), 100 + practical uses of (illus.), 100 + rusting, 100 + Silo (illus.), 102 + stable (illus.), 102 + sun dial (illus.), 101 + tensile strain, 104 + tower (illus.), 102 + walls (illus.), 100 + water tower (illus.), 102 + what it is, 95 + wood, 102 + + =Confucius=, philosophy written with brush, 13 + + =Cooking=, when first used, 308 + + =Copper=, as a conductor of electricity, 267 + wire, telegraph, 266 + + =Corn plant=, how pollen fertilizes, 170 + why it has silk, 176 + + =Corn Silk=, what it is for, 176 + baling presses (illus.), 476 + + =Cotton=, drawing frames (illus.), 472 + slashers (illus.), 475 + spinning frames (illus.), 473 + warping machine (illus.), 474 + what nation produces the most, 477 + how much cloth will a pound of cotton make, 477 + mill (illus.), 471 + cloth, first steps in making, 472 + putting fiber on bobbins (illus.), 473 + cloth finished (illus.), 476 + who discovered, 477 + weave room, 475 + where it comes from, 470 + lapper machines, 471 + card room (illus.), 472 + bobbins (illus.), 473 + dye-house (illus.), 474 + beaming frames (illus.), 475 + inspecting tables (illus.), 476 + field a southern (illus.), 470 + breaker machines (illus.), 471 + slubber machines (illus.), 472 + speeders (illus.), 473 + spooling machine (illus.), 474 + shipping (illus.), 476 + what used for, 477 + cloths, what are the principle, 477 + + =Counting=, man, himself, 19 + in tens, 19 + in twelves, 20 + + =Crying=, what makes us, 195 + when hurt, why we, 93 + + =Cross-bow=, invention of, 44 + + =Crude rubber=, how treated, 378 + + =Culverins=, early type of, 45 + + =Cylinder in gas engine= (illus.), 184 + + =Darkness=, cats can see in, 91 + some animals can see in, 91 + why we cannot see in, 91 + why we fear, 352 + + =Deep sea diving=, the telephone adjusting (illus.), 202 + coming up (illus.), 204 + cost of outfit, 203 + helmet, putting on (illus.), 202 + just before going down (illus.), 204 + outfit, 202 + shoes, putting on (illus.), 202 + suit, putting on (illus.), 202 + telephoning from bottom, 203 + telephone, testing the (illus.), 203 + testing, final (illus.), 203 + water pressure at varying depths, 203 + wealth recovered by diving, 204 + weight of outfit, 203 + + =Deer-stalking with the cross-bow= (illus.), 42 + + =Detonators=, in firearms, 47 + + =Developer=, Pyro, in photography, 23 + + =Diamonds=, what made of, 351 + + =Did= candles come before lamps? 294 + + =Die=, why do we have to, 245 + + =Difference= in woolens and worsteds, 84 + + =Dimples=, what causes, 352 + + =Discovery= of gunpowder, 44 + + =Discovery= of stringed musical instruments, 479 + telephone, 71 + + =Diver’s= task made easy (illus.), 284 + + =Diving, deep-sea=, the telephone adjusting, (illus.), 202 + cost of outfit, 203 + hats of divers, 204 + just before going down (illus.), 204 + helmet, putting on (illus.), 202 + shoes, putting on (illus.), 202 + suit, putting on the (illus.), 202 + suit, what consists of, 202 + telephone from bottom, 203 + telephoning, testing the (illus.), 203 + testing final (illus.), 203 + water pressure at varying depths, 203 + wealth recovered by diving, 204 + weight of outfit, 203 + + =Dixie=, what name means, 124 + where name originated, 123 + + =Does= air weigh anything, 398 + + =Does= the air surrounding the earth move with it? 400 + + =Does= thunder sour milk, 196 + + =Does= light weigh anything? 37 + + =Does= the sun revolve on its axis? 511 + + =Do= father and mother plants always live together? 176 + + =Do= the ends of the rainbow rest on land? 254 + + =Do= the stars really shoot down? 255 + + =Dog=, why he turns round before lying down, 229 + + =Dolls=, why girls like, 368 + + =Dom Pedro=, Emperor of Brazil, who saved the telephone, 73 + + =Do= plants breathe? 241 + + =Draft=, created by chimney, 37 + + =Dreams=, cause of, 366 + nightmare, 367 + what makes us? 366 + + =Drinking=, origin of clinking glasses, 232 + + =Driving shield=, airlock bulkhead (illus.), 210 + erector (illus.), 210 + in tunnel building (illus.), 208 + inventor of, 209 + tunnels, front view (illus.), 209 + + =Ducks=, why water runs off backs of, 233 + + =Dust=, in air, 38 + what it is, 104 + + =Dyeing=, silk, 121 + + =Earache=, what causes, 410 + + =Earth=, how big it is, 124 + light surrounding, 38 + + =Echo=, what makes an, 200 + whispering gallery, 201 + + =Eggs=, birds why different colors, 233 + silkworm, how imported, 111 + + =Egyptians=, how ancients wrote, 12 + + =Electric arc=, temperature of, 35 + + =Electric current=, what it is, 334 + + =Electricity=, conductors of, 331 + current, 334 + good conductors, 331 + how discovered, 333 + non-conductors, 331 + what is, 329 + + =Electric lighting=, arc-light, 307 + Edison’s first lamp (illus.), 306 + incandescent carbon lamp (illus.), 306 + Mazda lamp (illus.), 306 + tantalum lamp (illus.), 306 + Tungsten metal lamps, 305 + when introduced, 305 + + =Elements=, carbon, 352 + compared with compounds, 349 + hydrogen, 349 + nitrogen, 350 + oxygen, 349 + what an is, 349 + + =Elevator=, description of (illus.), 397 + installation (illus.), 396 + principal parts of, 396 + why does not the car fall? 397 + + =Emperor=, saved the telephone, 73 + + =Emperor of Brazil=, receives first message over first telephone, 74 + + =Engine, gas= (illus.), 181-182 + carburetor, 184 + cylinder (illus.), 184 + horse-power, of, 256 + + =Exchange=, first telephone, 75 + + =Exhibition=, of first telephone at Centennial, 74 + + =Experiments=, with mirror resultant in photograph, 22 + + =Exploding=, a submarine mine, 34 + + =Explosions=, how they break windows, 62 + in gas engines (illus.), 182 + of submarine mines (illus.), 34 + what happens in, 205 + + =Explosives=, definition of, 205 + blasting gelatin, 206 + gun-cotton, 206 + nitroglycerine, 206 + + =Eye=, of a submarine (illus.), 274 + + =Eyes=, closed, walking with, 91 + hand quicker than, 376 + help brain in walking, 91 + in some pictures follow you, why, 36 + keeping body balanced, 91 + nature’s way of protecting, 38 + protecting with tears, 38 + sparkle when merry, why, 92 + why we can’t sleep when open, 92 + why we see stars when hit on, 268 + + =Eye-wash=, tears as an, 38 + + =Fabrics=, worsted, 85 + + =Fahrenheit=, what is meant by, 221 + why so called, 221 + + =Fastest= camera in the world, 25 + + =Fathers and Mothers=, do plants have, 175 + + =Federal Government=, grazing fee paid to, 82 + + =Fertilization=, in birds, 179 + how corn plant fertilizes, 176 + of fishes, 177 + + =Fight=, of Merrimac and Monitor, 32 + + =Film=, before and after snapshot, 23 + sensitive, 23 + + =Finger prints=, arch, (illus.), 520 + composite (illus.), 521 + of different people, 521 + enlargements of, 524 + how they identify us, 520 + impressions of orang-outang (illus.), 522 + loop (illus.), 520 + palmary impressions (illus.), 522 + specimen form of, record (illus.), 525 + spike that caught a criminal (illus.), 524 + thieves caught through their, 523 + thumb imprint on bottle (illus.), 523 + thumb impression on cash box (illus.), 523 + thumb mark on a candle (illus.), 523 + where first used, 522 + whorl (illus.), 521 + + =Fingers=, why they hurt when cut, 143 + why we have ten, 142 + + =Finger nails=, why we have, 142 + + =Fire=, alarms when first used, 308 + first apparatus to fight, 308 + first fire department, 308 + first real, fire engine, 308 + gases put out, 37 + how man discovered, 289 + how man learned to fight, 208 + how man learned to make a, 289 + mark, of civilization, 290 + why it goes out, 37 + why is it hot? 401 + why put out by water, 222 + + =Fire making=, drilling (illus.), 289 + drilling with bow string (illus.), 290 + drilling, two persons (illus.), 290 + first matches (illus.), 292 + flint and pyrites (illus.), 290 + flint, introduction of (illus.), 291 + plowing (illus.), 290 + pyrites (illus.), 290 + rubbing sticks together, 42 + sawing (illus.), 289 + steel and flint (illus.), 291 + tinder box (illus.), 291 + tinder box, pistol (illus.), 291 + with matches, 292 + + =Firedamp=, 262 + explosion in safety lamp, 262 + + =Firearms=, first crude efforts of, 45 + first real (illus.), 45 + fuse of, 45 + in early Chinese history, 44 + first trigger of, 45 + + =Firing=, mortar, causes gas-rings, 27 + + =First= man-carrying aeroplane, 128 + real telegraph, 421 + stringed musical instrument, 480 + telephone (illus.), 72 + telephone line, 72 + telephone switchboard (illus.), 74 + + =Fishes=, how they are born, 177 + how they come to life, 177 + motion in swimming, 233 + what the eggs are, 177 + why they cannot live in air, 232 + + =Flag=, made, how was American, 310 + made, when was American? 310 + + =Flash pan=, early type, 45 + + =Flaxseed oil=, what it is, 227 + + =Flight=, of projectile, long, 30 + + =Flint-lock=, invented in seventeenth century, 46 + invented by thieves, 46 + still in use in Orient, 46 + + =Floor=, sounds through a, 79 + + =Flour=, bolters (illus.), 465 + how made, 462 + purifying machine (illus.), 463 + sieves, 465 + + =Flowers=, why they have smells, 176 + + =Flying=, how birds learn, 178 + boat, wonderful (illus.), 133 + first Langley monoplane, 126 + first successful aeroplane (illus.), 126 + machine, first models, 127 + some of the men who helped, 126 + ten years of (illus.), 137 + + =Flying boat=, fun in (illus.), 135 + gliding by, 137 + + =Flying boat=, interior arrangement (illus.), 134 + monoplane type (illus.), 135 + six-passenger hull (illus.), 134 + speed of (illus.), 135 + the wonderful, 133 + views of (illus.), 133 + + =Flying machines=, 126 + Bleriot flew in Europe (illus.), 129 + Curtis biplane in flight (illus.), 136 + Dr. Langley’s flying (illus.), 127 + early types of, 127 + first demonstrations, 130 + first flight in Europe with, 129 + first man-carrying aeroplane, 128 + first models, 127 + flying boat, 133 + flying boat, exterior arrangement, 134 + gliding experiments, 137 + government interest in, 138 + hull of flying boat, 134 + interesting governments in, 138 + Wright Bros., first flights, 130 + + =Focus=, in eye, 22 + + =Fog=, what it is, 105 + + =Food=, how we learned to cook, 308 + + =Foreign monoplanes=, some famous (illus.), 132 + + =Forsythe, LL.D. J.=, inventor of the primer, 47 + + =Freckles=, what makes them come, 125 + + =Fuse=, for firearms in early history, 45 + + =Funditor=, 42 + + =Gas=, acetylene, 305 + definition, 348 + first structure to be lighted by, 302 + in coal mines, 262 + water, 305 + + =Gas, illuminating=, Baltimore first city to use, 302 + carbon in, 302 + discovered, when, 302 + first American house to use, 302 + first practical demonstration of, 302 + generator house (illus.), 299 + holder (illus.), 298 + how it gets into jet, 302 + how it is purified, 303 + how made, 303 + how the meter works, 304 + hydrogen in, 302 + impurities removed from (illus.), 301 + jet, the story in a, 303 + made of, 302 + meter, description, 304 + purifying boxes (illus.), 301 + removing tar from, 300 + shaving scrubbers (illus.), 300 + + =Gasoline engine= (illus.), 181, 182 + + =Gases=, generated at gun muzzle, 27 + how expelled in gun ingot, 55 + hydrogen, 349 + nitrogen, 350 + oxygen, 349 + tendency to put out fire, 37 + + =Gas-rings=, in firing motor, 27 + + =Gatling=, inventor of guns, 310 + + =Gelatine=, in photography, 23 + + =Gestures=, talking by, 18 + + =Ghosts=, what are they? 367 + + =Glad=, why do we laugh when, 92 + + =Glass=, why it cracks, 63 + how long known, 247 + + =Glass, plate=, casting (illus.), 249 + commercial, 246 + plate and window glass compared (illus.), 252 + + =Glass, plate, making=, annealing, oven, 249 + beveling, 247 + blanketing, 252 + clay mixing (illus.), 248 + clay trampling (illus.), 248 + clay used, 247 + grinding table, 250 + materials used in, 247 + mercury, 253 + nitrate of silver, 253 + pots (illus.), 248 + pots, drying of, 248 + pots, length of usefulness, 248 + silvering, 247 + skimming the pot (illus.), 249 + treading, 247 + + =Glow-worm=, why does it glow? 231 + + =Gold=, why is it called precious? 266 + + =Gong=, why does it stop when it has been sounded, 78 + + =Good luck=, why a horseshoe brings? 311 + + =Graphite= in lead pencils, 468 + + =Gravitation=, what is, 267 + + =Gravity=, center of, in gun, 61 + + =Gravity=, force of, 61 + + =Greek fire=, in early history, 44 + + =Growing=, why do we stop, 195 + + =Gun=, action at muzzle, 27 + annealing a gun ingot, 57 + assembling of, 48-54 + arquebus of, 1537, 47 + barrels, erosion of, 35 + blow-holes, 56 + bore searcher, 59 + breech of a, 53 + discharges, force of, 33 + calibre of a, 53 + elastic limit, 58 + elongation, 58 + forging a (illus.), 52 + heat treatment, 58 + hoops of a, 54 + improvements in, 45 + ingot, calibre of, 55 + jacket of, 54 + length of a, 53 + liner of, 54 + life of, 35 + manufacture in America, 48 + measuring inside diameter (illus.), 59 + modern built-up (illus.), 54 + mold for ingot, 55 + muzzle of, 53 + pressure generated in a big gun, 54 + photography (illus.), 33 + piping, 56 + powder chamber of a, 53 + rifling (illus.), 60 + rifling of, 53 + shrinking pit, 59 + tensile strength of, 58 + factory, testing materials, (illus.), 50 + tube of, 54 + tube, how it is tempered, 57 + why called gatling, 310 + wire-wound, 54 + + =Gun-barrels=, imported from England, 49 + resisting pressure of, 34 + + =Gun-cotton=, in smokeless powder, 35, 206 + + =Gunpowder=, Chinese probable discovers of, 44 + discoverer of, 44 + experiments by Schwartz, 45 + formula of Roger Bacon, 45 + ingredients in, 205 + manufactured in monasteries, 44 + what causes the smoke? 206 + smokeless, what made of, 206 + why some is fine and others large grained, 206 + + =Gurgle=, in bottles, 63 + + =Hail=, what causes, 124 + + =Hair=, what causes baldness, 143 + why it don’t hurt when cut, 143 + why it keeps growing, 144 + + =Hand bombards=, early types, 45 + + =Hands=, shaking, why with the right, 231 + + =Hansom=, why so called, 122 + + =Have= plants fathers and mothers? 175 + + =Heart=, why beats during sleep, 191 + why beats faster when scared, 191 + why beats faster when running, 191 + + =Heat=, light wave changed into, 36 + why a nail gets hot when hammered, 230 + why some things are warm, 144 + how we obtain, 231 + + =Hemp=, Manilla (illus.), 356 + + =Hobson’s choice=, how originated, 311 + + =Honey=, apiary in summer (illus.), 534 + how produced, 527 + worker comb (illus.), 532 + manner of using German bee-brush, 533 + finished product (illus.), 533 + frame (illus.), 535 + how to bump the bees off a comb (illus.), 533 + bee-hat (illus.), 535 + a study in cell-making (illus.), 532 + bee sting, can a, 536 + frame of bees (illus.), 535 + comb, how bees build, 536 + + =Honey-bee=, poison-bag, 537 + egg of queen, under microscope (illus.), 529 + preparing for rearing, 531 + living on combs in open air, (illus.), 527 + the daily growth of larvæ (illus.), 532 + effect of a sting (illus.), 536 + worker-bee (illus.), 527 + what the queen-bee does? 528 + drone-comb (illus.), 532 + clipping queen bees wings (illus.), 533 + cucumber blossom with bee on it (illus.), 528 + queen-bee (illus.), 527 + the queen and her retinue (illus.), 529 + queen-rearing, 531 + queen-cells (illus.), 529 + + =Honeymoon=, why do they call it a? 311 + + =Horizon=, how far away is the, 245 + what is it, 244 + where is it, 244 + + =Horse-power=, a, what it is, 256 + + =Horseshoes=, why it is said to bring good luck? 311 + + =Hot box=, cause of, 368 + + =Houiller=, French gunsmith, 48 + + =Houses=, concrete (illus.), 101 + + =How= far does the air extend? 243 + is ammunition made (illus.)? 49 + does an arc light burn? 307 + are automobile tires made? 382 + does a honey bee live? 336 + does a bee make honey? 527 + do bees build the honey comb? 536 + does the honey bee defend itself? 536 + does honey develop in a comb (illus.)? 530 + do birds learn to fly? 178 + do birds find their way? 407 + does the blotter take up the ink of a blot? 18 + this book is bound, 578 + this book is made, 561 + the paper in this book is made, 561 + the pictures in this book are made, 581 + are bullets made? 51 + is an ocean cable laid? 429 + does a camera take a picture? 22 + is a cable dropped into the ocean (illus.)? 432 + are modern carpets made? 169 + is a carpet woven by machinery? 171 + is china decorated? 406 + is china made? 404 + is chocolate made? 392 + did the custom of clinking glasses in drinking originate? 232 + are cigars made? 517 + is cloth made from wool? 86 + did the coal get into the coal mines? 257 + does a coal mine look inside? 260 + do the cocoa beans grow (illus.)? 391 + is the color put on the outside of the pencil? 469 + is the honey comb made? 532 + are concrete roads built (illus.)? 103 + did man learn to cook his food? 308 + are concrete buildings made (illus.)? 100 + is woolen cloth dyed? 87 + big is the earth? 124 + much of the earth does the sun shine on at one time? 324 + does an elevator go up and down (illus.)? 396 + was electricity discovered? 333 + does the light get into the electric bulb? 305 + is the eraser put on a pencil? 469 + can an explosion break windows? 62 + explosions may occur on submarines, 278 + does the farmer use concrete (illus.)? 102 + do our finger prints identify us? 520 + did man learn to fight fire? 308 + did man learn to make a fire? 289 + are fishes born? 177 + was the flag made? 310 + is flour made? 462 + does a fly walk upside down? 454 + did men learn to fly? 126 + does the gas get into the gas jet? 302 + is illuminating gas made? 303 + is gas purified? 303 + is plate glass made? 246 + is plate glass ground? 250 + a wire-wound gun is made? 54 + was the first American gun made (illus.)? 47 + is a gun ingot made? 55 + do we find the length of a gun? 53 + is a gun tube tempered? 57 + do we obtain heat? 231 + the heel of a shoe is put on (illus.), 560 + did Hobson’s choice originate? 311 + far away is the horizon? 245 + does a key turn a lock (illus.)? 491 + does a spring lock work (illus.)? 492 + are lead pencils made? 467 + do the miners loosen the coal? 261 + is light produced, 230 + are magnets made? 335 + are matches made? 293 + are match boxes made? 294 + did man learn to send messages? 412 + does the meter measure the gas? 304 + can microbes spread through the body? 410 + are mirrors silvered? 522 + big is a molecule? 348 + did money originate? 455 + are moving pictures made? 369 + does the music get into the piano? 478-482 + did the word news originate? 312 + did a nod come to mean yes? 19 + did shaking the head come to mean no? 19 + are paints mixed? 228 + is a photograph developed? 23 + was the piano discovered? 479 + do plants breathe? 241 + do plants reproduce life? 175 + does the shield cut through the ground in tunnel building? 212 + are shooting shells photographed? 24 + shoes are made by machinery, 549 + shoe machinery was developed, 457 + is crude rubber secured? 377 + is rope turned and twisted? 358 + are rubber tires made? 378 + are modern rugs made? 169 + to splice a rope, 364 + do men go down to the bottom of the sea? 202 + did the sand get on the seashore? 108 + far back does the silkworm date? 109 + was silk introduced into Europe? 110 + are the silkworms cared for? 113 + do we know a thing is solid, liquid or gas? 348 + are sounds produced? 485 + fast does sound travel? 486 + can sound come through a thick wall? 79 + is the volume of sound measured? 242 + far does space reach? 256 + do the slate pickers work? 259 + does a captain steer his ship across the ocean? 407 + can a ship sail under water, 269 + is a submarine submerged? 270 + do sponges grow? 286 + do sponges eat? 287 + are sponges caught? 287 + are the stars counted? 241 + big is the sun? 141 + hot is the sun? 141 + is a steel pen made (illus.), 17 + did man learn to shoot, 40 + do we get wool off the sheep? 82 + is a stone thrown with a sling? 41 + are metallic and paper shells filled with powder? 50 + did man learn to talk? 18 + did the telephone come to be? 70 + fast does thought travel? 242 + does a telegram get there? 414 + did man learn to tell time? 313 + did man begin to measure time? 314 + did men tell time when the sun cast no shadows? 317 + is the time calculated at sea? 315 + is tobacco cultivated? 516 + is tobacco cured? 516 + was tobacco discovered? 512 + is tobacco harvested? 515 + is tobacco planted? 514 + is a tunnel dug under water? 208 + does water put fire out? 222 + is white lead made? 225 + are wires put under ground? 76 + did writing first come about? 11 + did the Chinese write? 13 + did the Monks do their writing? 14 + does a pen write? 18 + much does the wool in a suit of clothes cost? 83 + much wool does America produce? 82 + is wool taken from the sheep? 82 + is the yarn for carpets dyed? 170 + is oxide of zinc obtained? 226 + does the water get into the faucet? 501 + are the big water pipes laid? 504 + did the name Uncle Sam originate? 458 + + =Human body=, wonders of the, 311 + + =Hunting=, with the bow-and-arrow, 43 + + =Hurt=, why we cry when, 93 + + =Hydrogen=, what it is, 349 + + =Hypo=, used in developing, 23 + + =Impact=, of projectile from guns, 28 + + =Ink=, how does a blotter take up? 18 + + =Instruments=, artillery, testing, 24 + musical, 488 + optical, based on refraction, 38 + + =Incandescent lamp=, development of, 306 + + =Inside= of a mine planting submarine (illus.), 277 + + =Iron=, cast, 265 + melts at, 35 + the most valuable metal, 265 + wrought, 265 + + =Is= a moth attracted by a light? 288 + man an animal? 180 + the hand quicker than the eye? 376 + there a reason for everything? 200 + there a man in the moon? 400 + yawning infectious? 192 + + =Jacket=, of a gun, 54 + + =Japan= the natural home of the silk worm (illus.), 112 + + =Kentucky rifles=, 45 + + =Key=, how it works in a lock (illus.), 491 + + =Knots=, different kinds of (illus.), 363 + what makes, in boards, 223 + + =Lambs=, Siberian, in South Dakota (illus.), 80 + + =Lamps=, first street light in America, 296 + the Clanny safety, 264 + did candles come before? 294 + earliest forms of, 295 + Edison’s first (illus.), 306 + incandescent carbon (illus.), 306 + incandescent, development of, 306 + incandescent, electric, when invented, 305 + French watch tower (illus.), 295 + Mazda (illus.), 306 + from Nushagak hanging (illus.), 297 + Pagan votive (illus.), 296 + Tantalum (illus.), 306 + street, when first used, 295 + chimney protects flame, 37 + coal miners and safety, 262 + + =Lamp chimney=, why it makes a better light, 37 + + =Langley, Dr. Samuel P.=, 1914 flight of aeroplane, 128 + + =Languages=, why so many, 197 + + =Lantern=, the first oil (illus.), 297 + the “Réverbère” (illus.), 297 + + =Laugh=, when glad, why we, 92 + nerves, 93 + when tickled, why we, 93 + + =Laughter=, reflex action, 93 + + =Lead=, as used in making paint, 267 + in a pencil, 468 + why so heavy, 267 + as used in pipes for plumbing, 267 + + =Leather=, how the hides are treated, 539 + treatment of hides, 538 + unhairing machine (illus.), 540 + hide house (illus.), 538 + tanning process, 539 + rolling room (illus.), 539 + tanning sole leather, 539 + how upper leather is tanned (illus.), 540 + disposing of waste material, 540 + wringers, 539 + tan yard (illus.), 539 + + =Legs=, not same length, 91 + + =Lens=, in the eye, 22 + + =Leyden jar=, what it is, 332 + + =Life=, beginning of, 174 + beginning of man’s, 174 + how plants reproduce, 175 + + =Light=, attracting moths, 288 + glow-worms why they glow? 231 + how produced, 230 + lightning bugs, made by, 231 + where it goes when it goes out, 36 + what makes match, 198 + in mirror, 22 + in negative, 23 + rays, 36, 495 + broken rays of, 38 + rays, heat from, 36 + and refraction, 38 + speed of, 36, 140 + travels faster than anything in the world, 36 + surrounding earth, 38 + wave changed into heat, 36 + + =Lighting=, arc, how does it burn, 307 + in America, first street (illus.), 296 + first oil lantern, 297 + electric, when introduced, 305 + first street light in Paris, 297 + gas tank, (illus.), 298 + + =Lightning=, why it follows thunder, 140 + + =Lightning bugs=, why they produce light, 231 + + =Lignite=, found in coal mines, 262 + + =Liner=, of a gun, 54 + + =Linseed oil=, extraction of, 228 + what it is, 227 + where it comes from, 227 + + =Liquid=, definition, 348 + + =Living=, why do some people live longer, 199 + reproduction necessary why, 174 + reproduction of, in birds, 179 + reproduction of, in fishes, 177 + + =Loading= machines in powder factory, 50 + + =Lobsters=, red, what makes them, 245 + + =Lock=, cylinder (illus.), 492 + how a key turns a (illus.), 491 + how key changes are provided (illus.), 491 + how a spring lock works (illus.), 492 + master-keyed cylinder (illus.), 492 + what happens when the key is turned? (illus.), 491 + what happens when the knob is turned? (illus.), 491 + + =Locomotives=, boiler of articulate type (illus.), 440 + boiler of (illus.), 442 + cab of (illus.), 442 + cylinders description of, 441 + low pressure cylinders of (illus.), 441 + electric, newest (illus.), 443 + one of the largest (illus.), 440 + signal tower, latest (illus.), 444 + stoker, automatic (illus.), 443 + water tank (illus.), 444 + + =Lodestone=, what it is, 327 + + “=Long Bow=,” in Sherwood Forest (illus.), 42 + + =Loom=, cloth making machine, 86 + + =Magnet=, breaking iron (illus.), 330 + electro (illus.), 326, 328, 335 + electric lift (illus.), 326 + experiments with, 327 + great lifting by (illus.), 330 + how made, 335 + what makes it lift things? 326 + wonders performed by, 326 + work it can do (illus.), 328 + + =Man=, writing, how man learned, 11 + counting himself, 19 + is he an animal? 180 + + =Matches=, are they poisonous? 294 + first, 292 + how made, 293 + lucifer (illus.), 292 + making by machinery, 293 + modern safety (illus.), 292 + oxymuriate (illus.), 292 + promethean (illus.), 292 + what we would do without, 292 + when first used (illus.), 292 + + =Match-lock=, of early firearms, 45 + + =Melting= of iron, 35 + + =Men= who made the telephone, 70 + + =Mercury=, fulminate of, 49 + + =Merrimac and Monitor=, fight of, 32 + + =Merry=, why eyes sparkle when, 92 + + =Messages=, how men learned to send, 412 + Indian smoke signals, 412 + marathon runner by (illus.), 413 + pony telegraph (illus.), 413 + + =Messenger boy=, how to call a (illus.), 414 + the first (illus.), 413 + + =Metal=, what is a, 265 + what is the most valuable? 265 + why we use for coining, 456 + + =Meter=, description of gas, 304 + how it measures gas, 304 + + =Milk=, does thunder sour? 196 + + =Milky way=, why is it called, 255 + what is, 255 + + =Mine cars= (illus.), 260 + + =Mines=, clearing channel of buoyant, 283 + exploding submarine, 34 + planting submarine, inside of (illus.), 277 + workers that never see daylight, 258 + + =Mirror=, collects rays of light, 22 + reflection in, 22 + reflects rays of light, 22 + + =Mirrors=, beveling (illus.), 251 + how made, 251 + how silvered, 252 + polishing, 251 + roughing, 251 + silvered with mercury, 253 + silvering mirror plates (illus.), 252 + + =Molecule=, how big is a, 348 + what is a, 348 + + =Monasteries=, where gunpowder was manufactured, 44 + + =Money=, how originated, 455 + metallic forms of, 456 + who made the first cent, 458 + who originated, 455 + why do we need, 455 + why gold and silver are best for coining, 457 + + =Monitor and Merrimac=, fight of, 32 + + =Monks=, making gunpowder, 44 + + =Monoplane=, flying boat (illus.), 135 + German (illus.), 132 + over Mediterranean (illus.), 132 + + =Moon=, why it travels with us, 399 + the man in the, 400 + + =Morse, S. B.=, inventor of telegraph, 420 + + =Mortars= (illus.), 26 + + =Mothers and Fathers=, do plants have, 175 + + =Moths=, attracted by light, 288 + emerging from cocoon (illus.), 117 + + =Motion= bodies, swiftest, 25 + + =Motion=, is train harder to stop than start? 223 + of light, 140 + of sound, 140 + perpetual, 61 + perpetual, in mechanics, 240 + + =Motors=, gas, used in aeroplanes, 130 + + =Mountains=, what made them, 401 + + =Moving pictures=, Board of Censors, 373 + developing room (illus.), 372 + drying room (illus.), 373 + continuous movement of film, 376 + exact size of film, 370 + first camera, 375 + first exhibited at studio, 372 + how made, 369 + how freak pictures are made, 376 + negative, stock, 370 + negative, perforated, 370 + “Pigs is Pigs” (illus.), 374 + rehearsing (illus.), 371 + scenario (illus.), 374 + staging, 371 + taking a (illus.), 373 + + =Mulberry trees=, food for silk worms (illus.), 112 + + =Mules and drivers= (illus.), 258 + + =Multiple switchboard= of telephone, 69 + + =Music=, harp, 479 + lyre, 479 + note, what it is, 490 + what pitch is, 489 + what is, 478 + + =Musical talking machines=, 490 + + =Muzzle=, of a big gun, 53 + + =Muzzle-loaders=, in Civil War, 47 + + =Nails=, why they get hot when hammered, 230 + + =Names=, of people, 20 + + =Nature=, protecting eyes, ways of, 38 + + =Navigating= on bottom of sea, 283 + + =Negative= in photography, 23 + + =Nerves=, sensory, receive impression, 93 + transmitting impression, 22 + + =News=, how did the word originate? 312 + + =Nightmare=, cause of, 367 + + =Nitrogen=, what it is, 350 + + =Ocean=, why is it blue? 219 + what makes it green? 219 + why don’t water sink in? 219 + where did all the water in, come from? 218 + where is water at low tide, 219 + + =Of= what use is my hair? 143 + + =Of= what use are pains and aches? 410 + + =Oil baths=, for gun (illus.), 57 + + =Oil cake=, from linseed, 228 + + =Oil=, palm olive, in soap, 411 + + =Omniscope=, of submarine boat, 271 + + =Onions=, make tears, 38 + bad effect of on eyes, 38 + + =Operatives=, in powder factory, girls as, 49 + + =Optical instruments=, based on refraction, 38 + + =Organic matter=, what it is, 174 + + =Origin of cement=, 95 + of counting in tens, 19 + names of people, 20 + of nodding to indicate yes, 19 + of shaking head to indicate no, 19 + of turnpike, 104 + + =Oxide of zinc smelter= (illus.), 227 + how obtained, 226 + + =Oxygen=, what it is, 349 + in air, 37 + + =Pain=, of what use is, 410 + what it is, 244 + + =Paint=, care of, story in, 224 + how mixed, 228 + uses of, 224 + what used for, 224 + + =Paint manufacturing=, colors, what makes different, 229 + buckles before corrosion (illus.), 225 + buckles after corrosion (illus.), 225 + buckles placed in stacks (illus.), 225 + buckles taken from stacks (illus.), 225 + first step in making (illus.), 224 + lead buckles making (illus.), 224 + lead, white, how made, 224-225 + lead white used in, 224 + grinding lead in oil (illus.), 228 + washing the lead (illus.), 226 + mixing, 228 + where paints are mixed (illus.), 228 + linseed oil, where obtained, 227 + pressing oil from flaxseed (illus.), 228 + removing oil cake from press, 228 + sulphur roasting furnace (illus.), 226 + zinc smelter (illus.), 227 + oxide of zinc, how made, 226 + + =Paper=, earliest forms of, 14 + sensitive in photography, 23 + shells, inspection of (illus), 49 + papyrus, the first, 14 + + =Papyrus=, invention of, 14 + + =Patents=, of original telephone, 73 + + =Peat=, as a fuel, 262 + + =Pen=, first metallic (illus.), 15 + first steel (illus.), 15 + first metallic pen, how made, 15 + how it writes, 18 + invention of the, 15 + + =Pencils, “lead”= where from, 466 + eraser is put on, 469 + making description of (illus.), 467 + who made the first? 466 + + =Periscope=, description of, 275 + how we look through a (illus.), 276 + mirror of, 275 + + =Perpetual motion=, nearest approach to, 240 + is it possible? 61 + + =Persian rug=, antique (illus.), 167 + how made, 167 + imitation (illus.), 167 + Kurdistan (illus.), 167 + where best are made, 167 + + =Photographs=, of projectiles, 25 + + =Photography=, resultant from experiments with mirror, 22 + + =Piano=, pitch, 489 + finishing (illus.), 484 + why not more than seven octaves, 480 + Dulcimer (illus.), 479 + spinet (illus.), 480-481 + note what it is, 490 + sounding board, 488 + tuning, (illus.), 484 + building case around (illus.), 483 + how the music gets into the, 482 + clavichord (illus.), 480 + instruments, musical, 488 + strings, fastening on (illus.), 482 + psaltery, 480 + sound box, the first, 479 + who made the first, 478 + hammers (illus.), 483 + action regulation (illus.), 484 + virginal (illus.), 480-481 + first (illus.), 478 + tuning fork, 488 + polishing (illus.), 484 + sounding board, putting on the (illus.), 482 + how discovered, 479 + lyre, 479 + octave, 480 + harpsichord (illus.), 480-481 + + =Pickers=, boy, slate (illus.), 259 + + =Pictures=, with a fast camera, 39 + moving, how made, 369 + size of moving film, 370 + never seen by the human eye, 31 + taken in one five-thousandth of a second, 31 + + =Pin money=, why they call it? 231 + how name originated, 231 + + =Pistols=, invented in Pistola, Italy, 46 + + =Plants=, corn, why it has silk? 176 + do father and mother plants live together, 176 + how they eat, 511 + how they reproduce, 175 + why do flowers have smells? 176 + why they produce leaves, 175 + + =Plate glass=, (illus.), 246 + + =Portland Cement=, why called, 95 + + =Powder=, filling shells, 50 + gun-cotton in smokeless, 35 + secret of smokeless powder, 35 + smokeless, 35 + in submarine mines, amount of, 34 + + =Pressure=, generated in bore of a big gun, 54 + inside of a gun at discharge, 33 + in gun-barrel, resistance of, 34 + of light, on scales, 37 + + =Primer=, invented by, 47 + + =Prof. Bell’s= vibrating reed (illus.), 71 + + =Projectiles=, photographs of, 25 + arrival at target, 24 + clear of smoke-zone (illus.), 30 + smoke-zone, emerging from (illus.), 29 + height in air from mortar, 30 + impact of, from guns, 28 + leaving gun muzzle (illus.), 27 + travel faster than sound, 32 + velocity of, 33 + viewed in transit, 33 + weight of, 53 + + =Proving grounds=, for big guns, (illus.), 53 + + =Pyro=, used in developing, 23 + + =Quarry=, cement (illus.), 96 + + =Quill the=, in writing (illus.), 14 + + =Quills=, raising geese for, 14 + + =Rails, steel making=, blast furnace (illus.), 234 + blooming mill (illus.), 237 + crane, carrying ingot, (illus.), 236 + length of, 238 + mixer (illus.), 234 + molten steel, pouring (illus.), 236 + open hearth furnace (illus.), 235 + pouring side of open hearth furnace, 235 + shrinkage of, 238 + soaking pit (illus.), 236 + temperature in furnace, 235 + + =Rain=, where it goes, 222 + why it freshens the air, 222 + + =Rainbow=, cause of, 253 + colors in, what makes? 254 + ends of, 254 + + =Rays=, change their course, 38 + heat from light, 36 + of light, 36 + Roentgen, 307 + + =Rays-X=, what are they? 307 + + =Reason=, is there one for everything? 200 + + =Reed=, the (illus.), 12 + + =Reflection=, in mirror, 22, 91 + + =Refraction=, changing light rays called, 38 + of light, 38 + + =Reproduction=, of life, in birds, 179 + in fishes, 177 + in plants, 175 + why we must have, 174 + + =Rifle=, Kentucky, 45 + kick of, 47 + modern automatic, 47 + over-loading, 47 + wheel-lock (illus.), 46 + + =Rifling=, causes rotation of projectile, 32 + a big gun (illus.), 60 + of a gun, 53 + invented in Austria, 46 + + =Roads=, concrete (illus.), 103 + + =Roentgen Rays=, 307 + + =Rope=, breaker (illus.), 360 + compound laying machine (illus.), 361 + cross-section, 362 + draw frame (illus.), 360 + drying fiber, 354 + Egyptian kitchen (illus.), 354 + Egyptians making (illus.), 353 + preparing the fiber in (illus.), 359 + four-strand (illus.), 362 + hackling, 354 + hemp (illus.), 356 + hemp in warehouse (illus.), 356 + knots, 363 + lengths, standard, 362 + oiling in manufacture, 356 + long made by hand, 354 + machine (illus.), 358 + opening bales of fiber (illus.), 359 + preparation room (illus.), 359 + scraping fiber (illus.), 354 + sliver formation of (illus.), 360 + spindles, 355 + spinning after turn, 355 + + =Rope spinning=, after turn, 355 + foreturn, 355 + splicing (illus.), 364 + spreader (illus.), 360 + stakes, 355 + + =Rope walk=, modern (illus.), 357-358 + old-fashioned (illus.), 355 + + =Routine=, of a telephone call (illus.), 68 + + =Rubber=, automobile tires, 382 + biscuit, 377 + blisters, 379 + blow holes, 379 + breaker-strip, 384 + calendering, 381 + castilloa, 387 + cement, 381 + crude, 377-378 + curing room, 382-383 + dryer, 379 + fabric, 384 + furnishing pneumatic tires (illus.), 386 + gathering (illus.), 377 + how secured, 377 + how are inner tubes made, 385 + marketing balls of, 377 + mixing, 379 + Para, 387 + pneumatic tires, 383 + pure, why not used, 380 + spreading, 381 + spreader room (illus.), 383 + tapping (illus.), 377 + tire building machines (illus.), 385 + tires, how made, 378-379-380 + tread laying room, 384 + tubes, inner, how made, 385 + vulcanizing, 384 + washing, 378 + wild, what is, 387 + why not used pure, 380 + wrapping room, 386 + + =Rugs=, designs imitated by machinery, 168 + Persian (illus.), 167 + Persian, how made, 167 + Persian, imitation, 167 + Persian Kurdistan (illus.), 167 + Persian, where best are made, 167 + Tabriz, reproduction (illus.), 168 + weaving by machine (illus.), 171 + + =Rug manufacturing=, carding machine (illus.), 170 + examining and repairing (illus.), 173 + packing for shipment (illus.), 173 + processes, 169-170 + weaving by machinery (illus.), 171 + wool sorting, 170 + + =Sadness=, cause of tears, 38 + + =Salt=, beds, 493 + chemical name of, 493 + in water, 351 + mines, 493 + Salt Lake, 493 + soda, 493 + supply for United States, 493 + wells, 493 + where it comes from, 493 + + =Scales=, pressure of light on, 37 + + =School slates=, where they come from, 495 + + =Score=, origin of, 26 + + =Scouring=, wool (illus.), 85 + + =Scouring and weaving=, in making woolen cloth (illus.), 88 + + =Screens=, in shot tower, 51 + + =Sea=, diver, 202 + how men go down to the bottom of, 202 + navigating on bottom of, 283 + time calculated on the, 315 + what the bottom looks like, 202 + what makes it roar, 401 + + =Second=, reckoning in millionths of a, 25 + pictures taken in one five-thousandth of a, 31 + + =Seeds=, why plants produce, 175 + + =Seeing=, why we cannot see in dark, 91 + + =Sensation=, of sight, 22 + + =Sensitive=, paper, 23 + + =Service=, military, U. S., 24 + + =Shadows=, cause of, 495 + + =Shell=, sounds in a, 79 + + =Shells=, filling with powder, 50 + inspection of metallic (illus.), 49 + putting metal heads on paper, 50 + wad-paper in making, 50 + + =Sheep=, coming out of forest (illus.), 82 + first in America, 80 + fleece packing, 82 + how much wool does a sheep produce? 83 + how wool is taken from the, 82 + how taken care of, 82 + how we get wool off of, 82 + industry in America, 80 + industry in the colonies, 81 + industry in the west, 81 + number in the west, 81 + shearing, 82 + shearing machines, 82 + wool-producing, 83 + why sheep precede the plow in civilizing a + country, 81 + + =Shield driving=, air lock bulkhead (illus.), 210 + caulking the joints (illus.), 214 + description of airlocks, 213 + erector at work (illus.), 214 + erector (illus.), 210 + at end of journey (illus.), 216 + grommetting the bolts (illus.), 214 + grouting (illus.), 214 + how it cuts in tunnel building, 212 + how they meet exactly (illus.), 215 + in tunnel building (illus.), 208 + key plate (illus.), 214 + curves around (illus.), 216 + models of Penna. R.R. tunnel shields (illus.), 212 + rear end in tunnel building (illus.), 210 + tunnels, front view (illus.), 209 + + =Ship=, how does a captain steer his, 407 + how can it sail under water? 269 + + =Shoes=, Amazeen skiving machine, 550 + assembling machine (illus.), 552 + automatic heel loading and attaching + machine (illus.), 560 + automatic leveling machine (illus.), 559 + automatic sewing machine, 555 + American made, 547 + ancient and modern forms of sandals, (illus.), 543 + ancient sandal maker (illus.), 541 + beginning of a shoe (illus.), 549 + boot developed from the sandal, 544 + boots (illus.), 546 + channel cementing machine (illus.), 558 + channel laying machine (illus.), 559 + channel opening machine (illus.), 558 + Crakrow or peaked (illus.), 544 + which church and law forbade (illus.), 544 + description of ancient sandal (illus.), 542 + dyeing out machine, 551 + different parts come together, 551 + duplex eyeletting machine, 550 + edge trimming machine (illus.), 560 + Ensign lacing machine, 551 + evolution cf the sandal to the shoe (illus.), 542 + first machine for making shoes, 545 + hand method lasting machine (illus.), 553 + heel breasting machine (illus.), 560 + heel trimming machine (illus.), 560 + ideal clicking machine, 550 + Inseam trimming machine (illus.), 556 + insole tacking, 551 + lasting machine (illus.), 553 + loose nailing machine (illus.), 559 + success of McKay machine, 547 + machine that forms and drives tacks, 554 + machines which punch the soles of, 559 + my lady’s slippers (illus.), 548 + placing shank and filling bottom, 556 + planet rounding machine, 551 + power tip press, 550 + pulling over machine (illus.), 552 + putting the ground cork and rubber cement in, 556 + rolling machine, 551 + rounding and channelling machine (illus.), 557 + sewing the sole on, 558 + slugging machine (illus.), 560 + sole laying machine (illus.), 557 + Summit splitting machine, 551 + upper stapling machine (illus.), 554 + upper trimming machine (illus.), 554 + welt and turned shoe machine (illus.), 555 + welt beating and washing machine, 556 + welt sewing machine, 551 + what was the first foot covering like? 541 + “whipping the cat,” 545 + who made the first shoe in America? 545 + work performed by heeling machine (illus.), 560 + + =Shooting tests= (illus.), 48 + + =Shotguns=, assembling of, (illus.), 48 + + =Shot pellets=, 51 + + =Shrinking=, pit for big gun, 59 + + =Shuttle=, In weaving wool, 86 + + =Siberian lambs=, in South Dakota (illus.), 80 + + =Signs=, talking by, 18 + + =Silica=, mine (illus.), 247 + + =Silk=, 109 + called “bomby-kia,” 110 + caring for young worms, 113 + culture, 110 + drying skeins of, 119 + dyeing, 121 + first step in manufacture, 119 + first used, 109 + hatching eggs, 113 + introduction of into Europe (illus.), 110 + number of cocoons in pound of, 117 + manufacture of, 119 + method of reeling, 113 + moths depositing eggs (illus.), 112 + preparing cocooning beds, 112 + reeling silk from cocoon (illus.), 118 + spinning (illus.), 120 + thread made uniform (illus.), 120 + threads ready for the weaver, 121 + twisting (illus.), 120 + use of, 109 + water-stretcher (illus.), 121 + winding (illus.), 119 + + =Silk manufacture=, doubling frames, 120 + spinning, 120 + twisting, 120 + + =Silk moth=, description of 114 + + =Silkworm=, age, 115 + first breeder of, 109 + chrysalis (illus.), 114 + cocoon, 115 + cocoon, beginning of (illus.), 116 + cocooning bed (illus.), 112 + description of, 114 + domestication of, 111 + eating (illus.), 115 + female moth (illus.), 114 + how cared for, 113 + how it eats, 115 + home of, 112 + eggs, how imported, 111 + hatching the eggs (illus.), 113 + how he does his work, 114 + larvæ of, (illus.), 114 + motions of head in spinning, 115 + molting season, 115 + moths emerging from cocoon (illus.), 117 + male moth (illus.), 114 + mulberry branches for (illus.), 112 + one of the world’s greatest wonders, 116 + preparing for making cocoon (illus.), 116 + reared, how they (illus.), 115 + shedding old skin, 115 + spinneret of the, 115 + spinning cocoon, 115 + wild, 109 + + =Silver=, definition of, 207 + use, history of, 207 + why does it tarnish, 266 + + =Silver bromide=, in photography, 23 + + =Skins=, used for clothing, 80 + + =Sky=, will it ever fall? 255 + why is it blue? 253 + + =Soap=, lye in, 411 + palm olive oil in, 411 + what made of, 411 + + =Soda=, Leblanc process, 494 + Solvay process, 494 + where we get, 494 + + =Solids=, definition, 348 + + =Some= wonders of the human body, 311 + + =Sound=, deadening of, 79 + first over a wire, 71 + how measured, 242 + how produced, 485 + speed of, 140-486 + travels through air slowly, 31 + in a sea shell, 79 + what is, 78-485 + waves, 79 + waves, length of, 487 + where comes from, 78 + + =Slate pencil=, why cannot write on paper with, 18 + + =Sleep=, where are we when, 365 + with eyes open, why we cannot, 92 + ghosts, 367 + why heart beats during, 191 + why we go to, 365 + restless, 92 + + =Sling=, man in action (illus.), 41 + how first made, 41 + + =Slings=, and their drawbacks, 42 + + =Slow match=, of early firearms, 45 + + =Smells=, why do flowers have, 176 + + =Smoke-cone=, in gun-firing (illus.), 28 + + =Smokeless powder=, 35 + + =Smoke-rings=, hard as steel, 27 + + =Smoke signals=, of Indians, 412 + + =Smoke-zone=, in gun firing, 111 + + =Sneezing=, what makes us, 194 + why do we, 194 + + =Snowflakes=, what makes them white? 409 + + =Space=, extends, how far, 256 + + =Sparkle=, when merry, why eyes, 92 + + =Spear=, as a weapon, 42 + + =Specific gravity=, meaning of, 268 + + =Speed=, of light, 36 + + =Spinneret=, of the silkworm, 115 + + =Spinning wheel=, in making cloth from wool, 81 + + =Sponge=, capillary attraction of, 18 + + =Sponges=, breeding time of, 286 + how do they grow? 286 + how they eat, 287 + how they are caught, 287 + where they come from? 286 + + =Stable=, underground (illus.), 158 + + =Stars=, counted in photograph, 223 + do they shoot down? 255 + how counted, 241 + how many there are, 223 + photographed, 223 + what makes them twinkle, 38 + + =Steamship=, beginning of (illus.), 337 + cross-section, 346 + building of a (illus.), 337 + cradle of a, 338 + double bottom, 339 + end to end section, 346-347 + funnel (illus.), 345 + gantry (illus.), 338 + hull (illus.), 341 + hull before launching (illus.), 340 + inside of (illus.), 346-347 + launching of a (illus.), 340 + launching machinery (illus.), 341 + ready to launch (illus.), 340 + plates (illus.), 339 + ribs (illus.), 338 + skeleton (illus.), 339 + turbine, weight of, 344 + turbine (illus.), 344 + + =Steel pen=, how made, 16 + + =Steel rail making=, blast furnace (illus.), 234 + Blooming mill and engine (illus.), 237 + dump buggy, 237 + crane, carrying ingot (illus.), 236 + ingot, 237 + ingot becomes a rail (illus.), 238 + mixer (illus.), 234 + molten steel being poured into ladle (illus.), 236 + open-hearth furnace (illus.), 235 + furnace, pouring sides of an open hearth (illus.), 235 + iron, purification of, 235 + soaking pit (illus.), 236 + furnace, temperature in, 235 + + =Stick=, why it bends in water, 38 + making a fire with, 42 + + =Stockings=, where it goes when the hole comes, 64 + + =Stone-throwing=, 41 + + =Stones=, where they come from, 494 + + =Story= in an automobile, 181 + in a loaf of bread, 460 + in a book, 561 + in a building foundation, 496 + in a cablegram, 428 + in a barrel of cement, 95 + in a stick of chocolate, 388 + in a suit of clothes, 80 + in a lump of coal, 257 + in a bale of cotton, 470 + of a cup and saucer, 404 + of the deep sea diver, 203 + in an electric light, 305 + in an elevator, 395 + in a finger print, 520 + in a flying machine, 126 + in a gas jet, 303 + in a gun, 40 + in a honey bee, 526 + in a magnet (illus.), 326 + in a lead pencil, 466 + in lighting a fire, 289 + in a lock, 491 + in a can of paint, 224 + in a pen, 11 + in a piano, 478 + in a photograph, 22 + in “Pigs is Pigs” (illus.), 374 + in a pipe and cigar, 512 + in a railroad engine, 440 + in a coil of rope, 353 + in a ball of rubber (illus.), 378 + in a rug, 167 + in a pair of shoes, 541 + in a steel rail (illus.), 234 + in a submarine boat (illus.), 269 + in a lump of sugar, 145 + in a telegram, 412 + in the telephone, 65 + in a time piece, 313 + in a tunnel, 208 + in a drink of water, 501 + in a window pane, 246 + in the wireless, 455 + in a yard of silk, 109 + in a piece of leather, 538 + + =Stringed instruments=, the first, 480 + discovery of, 479 + + =Stretching=, why do we, 192 + what happens when we, 193 + + =Stylus=, iron, 13 + the in writing (illus.), 11 + + =Submarine=, accidents and their causes, 278 + air and how it may become poisonous, 278 + buoyancy of, 270 + “Bushnell’s Turtle,” 280 + cargo, recovering of, 285 + clearing a channel of buoyant mines (illus.), 283 + development of, 280-281 + divers’ compartment, 270 + equilibrium, 270 + explosions, 278 + first practical (illus.), 271 + gas, explosion of, 278 + “G-1” (illus.), 272 + Holland, 282 + how we look through a periscope (illus.), 276 + hydroplanes on, 270 + hydroplane, 282 + ice, under (illus.), 279 + inside of a (illus.), 272 + lens, of periscope (illus.), 276 + living quarters (illus.), 285 + mice on, 278 + mine planting inside of (illus.), 277 + Omniscope, 271 + one of the first practical, 271 + “Proctor,” first practical, 271 + “Proctor” submerged (illus.), 271 + periscope top of (illus.), 276 + rudder, horizontal, 270 + sailing close to surface (illus.), 273 + seeing in all directions at once, 276 + Simon Lake, American inventor of, 282 + steadiness of (illus.), 273 + under the ice (illus.), 279 + submergence, 270 + water pressure on, 270 + who made the first, 280 + + =Submarine boat=, “Argonaut the First” (illus.), 269-282 + “Argonaut Junior” (illus.), 269-282 + who made the first, 280 + + =Submarine mines=, amount of powder used, 34 + + =Sugar=, carbonatation station (illus.), 150 + chemical laboratory in factory (illus.), 149 + circular diffusion battery in factory (illus.) 149 + filter presses (illus.), 150 + how taken from beets, 150 + sulphur station (illus.), 150 + washing the beets, 149 + + =Sugar factory=, carbonatation station (illus.), 150 + chemical laboratory in (illus.), 149 + circular diffusion battery (illus.), 149 + filter presses (illus.), 150 + sulphur station (illus.), 150 + + =Suit=, cost of wool in a, 83 + + =Sulphite of soda=, used in developing, 23 + + =Sun=, distance from earth, 141 + revolving on its axis, 511 + + =Sun-dial= (illus.), 315 + in determining noon (illus.), 316 + concrete (illus.), 101 + + =Sunlight=, effect on balance, 37 + + =Sunset=, cause of colors in, 253 + + =Swallowing=, what happens when we, 195 + + =Swimming=, why man must learn, 125 + + =Switchboard=, telephone, 69 + back of a, telephone (illus.), 69 + telephone, the first (illus.), 74 + + =Talking=, how man learned talking, 18 + signs and gestures, 18 + + =Talking machines=, 490 + + =Target=, floating, 31 + Never seen by men firing mortar, 29 + projectile, arrival at, 24 + + =Tears=, caused by onions, 38 + as an eye-wash, 38 + run along channel, 38 + where they come from, 94 + where they go, 94 + + =Teeth=, why they are called wisdom, 125 + why they chatter, 218 + + =Telegram=, how it gets there, 414 + story in a, 412 + + =Telegraph=, cables (illus.), 424 + code, 419 + calling a messenger, 414 + waiting calls (illus.), 414 + arrival at destination (illus.), 417 + duplex, 417 + electric, 420 + electric, first suggestion of, 420 + inventor of, 420 + two men inventors of, 421 + instruments, 425 + instruments, first sending (illus.), 426 + instrument, sending, 418 + key, modern (illus.), 427 + key, a later, 427 + key, sending (illus.), 418 + line, first, 422 + messenger receives message (illus.), 415 + messages, number sent in a day, 417 + multiplex, 417 + operating room (illus.), 423 + the pony (illus.), 413 + quadruple, 417 + Wheatstone, receiver (illus.), 425 + Wheatstone sender (illus.), 425 + receiving operator (illus.), 416 + relay, the first (illus.), 426 + relay, modern (illus.), 427 + recording apparatus first (illus.), 426 + recording instrument improved, (illus.), 427 + repeater room (illus.), 424 + sending operator (illus.), 416 + sounder, modern (illus.), 427 + main switchboard (illus.), 423 + automatic typewriter (illus.), 425 + + =Telephone=, apparatus, 65 + birthplace of (illus.), 70 + cost of number in use (illus.), 77 + display board (illus.), 65 + discovery of, 71 + feeding cable into duct (illus.), 76 + first outdoor demonstration, 75 + how an emperor saved the, 73 + forces behind your, 77 + modern distributing frame (illus.), 75 + line, the first, 72 + line lamp, 66 + pilot lamp, 66 + from bottom of ocean, 203 + operator, 67 + breaking up the asphalt pavement (illus.), 76 + a cable trouble (illus.), 76 + call routine of (illus.), 68 + beginning of service, 75 + the first switchboard, 72 + laying multiple duct subway (illus.), 76 + first practical commercial test of telephone, 75 + how wires are put underground (illus.), 76 + nine million in use, 75 + the first words over, 74 + + =Tens=, counting in, 19 + + =Test=, of big gun (illus.), 53 + + =Testing=, materials and products in gun factory (illus.), 50 + artillery instruments, 24 + + =Tests=, shooting (illus.), 48 + + =Things=, to know about a big gun, 53 + + =Throats=, making sounds with our, 78 + + =Thread=, silk, made uniform (illus.), 120 + + =Thunder=, why it precedes lighting, 140 + does it sour milk? 196 + + =Tickled=, why we laugh when, 93 + + =Tides=, where does water go at, low, 219 + + =Time=, age of clocks, 391 + blacksmith’s clock (illus.), 320 + first modern clock, 319 + hour-glass (illus.), 317 + time-boy of India (illus.), 317 + where the day changes, 325 + where is the hour changed? 325 + clock in Independence Hall (illus.), 323 + clock in New York City Hall (illus.), 323 + largest clock in the world, 321 + machinery which runs a big clock (illus.), 322 + how man measured, 314 + modern clock, description of (illus.), 319 + primitive twelve-hour clock, 318 + water clocks for, 317 + water-clock (illus.), 318 + man’s first divisions of, 314 + what it is, 313 + three great steps in measuring, 316 + first methods of telling (illus.), 313 + in New Testament, 314 + sun-dial (illus.), 315 + sun-dial in determining noon, 316 + calculated at sea, 315 + tower of the winds (illus.), 318 + how told when sun casts no shadows, 317 + + =Tin=, why used for cooking utensils, 267 + + =Tobacco=, barn, 515 + growing crop, care of, 514 + growing under cheesecloth (illus.), 512 + grown in Cuba, 513 + cultivation of, 516 + curing of, 515 + cigars, how made, 517 + how discovered, 512 + field (illus.), 515 + figures about, 519 + filler, 518 + fertilization, 514 + where it comes from, 512 + shade growing, 517 + where does it grow, 512 + harvesting, 515 + Havana, where grown, 513 + origin of name, 512 + planting, 514 + seed beds, 514 + first care in selection, 518 + strippers, 518 + bulk sweating, 516 + wrappers, 518 + butter worm, 514 + + =Toes=, why we have ten, 142 + + =Toothache=, what good can come from? 410 + cause of, 410 + + =Torches=, used in battles, 44 + + =Tow-line=, of floating target, 31 + + =Trains=, why harder to stop than start, 223 + + =Transparent=, why some things are, 350 + + =Trees=, found in coal, 261 + + =Tube=, of a gun, 54 + + =Tunnels=, accidents in, 218 + causes of accidents, 218 + accuracy of engineering, 215 + airlocks, description of, 213 + operation of airlocks, 213 + compressed air method, 211 + the bends, 213 + bends, the danger of, 213 + bends, the symptoms of, 213 + dangers in building, 218 + grommetting the bolts, (illus.), 214 + borings in ground (illus.), 216 + airlock bulkhead (illus.), 210 + how built, 209 + driving shield rear end of in tunnel building (illus.), 210 + caissons in Hudson tunnels (illus.), 217 + curves, how made (illus.), 216 + how shield cuts through, 212 + how dug under water, 208 + erector (illus.), 210 + erector at work (illus.), 214 + grouting (illus.), 214 + inventor of shield method, 209 + inventor of compressed air method, 211 + caulking the joints (illus.), 214 + making joints water tight, 214 + at end of journey (illus.), 216 + land end of Hudson tunnels (illus.), 217 + danger of leaks, 213 + result of leaks (illus.), 213 + concrete lining (illus.), 216 + key plate (illus.), 214 + diagrams of driving shield (illus.), 208 + biggest ever built by shield method, 209 + rear end of driving shield (illus.), 210 + driving shield front view (illus.), 209 + how the shields meet exactly (illus.), 215 + models of Penna RR. tunnel shield (illus.), 212 + + =Turbine=, how it works (illus.), 344 + + =Twinkle=, what makes stars, 38 + + =Twinkling stars=, due to interference, 38 + + =Types= of cartridges (illus.), 49 + + =Umbrella=, who made the first, 312 + who carried the first, 312 + + =Uncle Sam=, how name originated, 458 + + =Undercutting= with compressed air machine (illus.), 261 + + =Vault= of telephone cables (illus.), 67 + + =Velocity= of a projectile, 53 + + =Waking=, why we wake up, 365 + + =Walking=, difficult to, straight with eyes closed, 91 + why cannot babies walk as soon as born, 180 + + =Wall=, sounds through a thick, 79 + + =Water=, aqueduct (illus.), 505 + Ashokan Reservoir (illus.), 502 + boiling-point of, 35-220 + drinking, where does it come from, 501 + hard, 221 + how is a big dam built, 502 + Hudson River siphon (illus.), 507 + in ocean where it came from, 218 + pumping station (illus.), 503 + real source of the (illus.), 506 + regulating chamber (illus.), 506 + reservoir, 503 + soft, 221 + as standard in measuring specific gravity + solids, 268 + what made of, 348 + what makes it boil, 220 + what makes water shoot in air, 198 + what hard is, 221 + what soft is, 221 + why don’t water in ocean sink in, 219 + why does it run, 219 + why it puts fire out, 222 + why runs off a duck’s back, 233 + why sea water is salty, 351 + + =Watson, Thomas A.=, (illus.), 70 + + =Wave=, of light changed into heat, 36 + + =Waves=, of sound, 79 + + =Weight=, of light, 37 + of projectiles, 53 + + =What= does the air weigh? 398 + animal can leap the greatest distance? 122 + causes an arrow to fly? 408 + makes some people bald? 143 + keeps a balloon up? 199 + makes a ball stop bouncing, 63 + are ball bearings? 180 + happens when a bee stings? 537 + makes the hills look blue sometimes? 255 + makes me blush? 194 + was the origin and meaning of bread? 460 + is the hottest spot on earth? 239 + holds a building up? 496 + makes a bubble explode, 108 + is carbonic acid? 509 + is a cable made of? 429 + is the eye of the camera? 22 + do ocean cables look like when cut in two? (illus.), 428 + do we mean by 18-carat fine? 266 + is clay? 495 + is color? 123 + produces the colors we see? 123 + makes the colors in the rainbow? 254 + makes the colors of the sunset? 253 + are cocoa shells? 390 + is cement? 95 + is cement used for? 95 + a cement mill looks like (illus.), 96 + is cement made of? 95 + is cement used for, 95 + is concrete? 95 + makes some things in the same room colder than others? 144 + does woolen cloth come from? 80 + was the cross-bow? 44 + are diamonds made of? 351 + causes dimples? 352 + makes us dream? 366 + were man’s first divisions of time? 314 + makes things whirl around when I am dizzy? 402 + is dust? 104 + becomes of the dust? 104 + are drone bees good for? 531 + is meant by deadening a floor or a wall? 79 + causes earache? 410 + makes an echo? 200 + are the principal parts of an elevator? 396 + causes the explosion in a gas engine? (illus.), 182 + happens when anything explodes? 205 + is an element? 349 + makes the hollow place in a boiled egg? 179 + is electricity? 329 + is an electric current? 334 + makes an electric magnet lift things? 326 + do we mean by Fahrenheit? 221 + makes a fish move in swimming? 233 + is fog? 105 + makes the water from a fountain shoot into the air? 198 + makes freckles come? 125 + makes a gasoline engine go? 181 + is gravitation? 267 + does specific gravity mean? 268 + makes a cold glass crack if we put hot water in it? 63 + are ghosts? 367 + causes the gurgle when I pour water from a bottle? 63 + causes hail? 124 + is the horizon? 244 + causes a hot box? 368 + good are the lines on the palms of our hands? 402 + does horse-power mean? 256 + is hydrogen gas? 349 + makes us feel hungry? 243 + makes knots in boards? 223 + were the earliest lamps? 295 + were the lamps of the wise and foolish maidens? 295 + happens when we laugh? 93 + makes us laugh when glad? 92 + is a leyden jar? 332 + is a lodestone? 327 + makes lobsters turn red? 245 + makes the lump come in my throat when I cry? 195 + makes a match light when we strike it? 198 + would we do without matches? 292 + is a metal? 265 + is the most valuable metal? 265 + is the milky way? 255 + is a molecule? 348 + is money? 455 + is motion? 61 + made the mountains? 401 + is music? 478 + does a note in music consist of? 490 + is organic matter? 174 + is oxygen? 349 + is nitrogen? 350 + makes nitroglycerin explode so readily? 206 + causes nightmare? 367 + is pain and why does it hurt? 244 + makes the different colors in paint? 229 + is pitch in music? 489 + is the principle of the wireless? 455 + makes some pencils hard and others soft? 467 + makes rays of light? 230 + makes us red in the face? 192 + makes the rings in the water when I throw + a stone into it? 197 + is rubber? 386 + is wild rubber? 387 + should I do if stung by a bee? 537 + is the cause of shadows? 495 + makes the sea roar? 401 + does the bottom of the sea look like? 220 + becomes of the smoke? 106 + and why is smoke? 105 + causes the smoke when a gun goes off? 206 + is smokeless powder made of? 206 + makes snowflakes white? 409 + depth of snow is equivalent to an inch of rain? 241 + is soap made of? 411 + makes a soap bubble? 108 + shot tower looks like? 51 + makes us sneeze? 194 + is silver? 207 + happens when we stretch? 193 + makes me want to stretch? 192 + happens when I swallow? 195 + is sound? 485 + are the properties of sound? 486 + are the sounds we hear in a sea shell? 79 + makes the sounds like waves in a sea shell? 79 + does a sounding board do? 488 + is meant by the length of sound waves? 487 + makes us thirsty? 243 + makes me tired? 403 + a great steamship looks like inside (illus.), 346 + did the first telephone look like? (illus.), 72 + occurs when we think? 194 + are the big tanks near the gas works for? 298 + makes the stars twinkle? 38 + a ship’s turbine looks like (illus.), 344 + is the largest tree in the world? 242 + happens when we telephone? 65 + makes water boil? 220 + is the boiling-point of water? 220 + causes a whispering gallery? 201 + makes a wireless message go? 455 + makes the works of a watch go? 368 + makes the white caps on the waves white? 410 + is worry? 207 + causes the wind’s whistle? 139 + makes the kettle whistle? 198 + causes wrinkles? 196 + are X-rays? 307 + is yeast? 288 + + =When= did man first try to fly? 126 + did man begin to live? 174 + were candles introduced? 296 + was illuminating gas discovered? 302 + was wheat first used in making bread? 461 + I throw a ball into the air, while walking why does it follow me? + 401 + was silk culture introduced in America? 111 + were street lamps first used? 295 + + =Where= does bread come from? 460 + does water in the ocean go at low tide? 219 + does silk come from? 109 + are we when asleep? 365 + did the name calico come from? 123 + cement is obtained (illus.), 97 + does chalk come from? 18 + does chocolate come from? 388 + our coal comes from? 257 + does cotton come from? 470 + does the day begin? 324 + does the day change? 325 + did the term Dixie originate? 123 + does honey come from? 526 + is the horizon? 244 + does the hour change? 325 + the gas is taken from the coal (illus.), 299 + did all the names of people come from? 20 + did the expression “kick the bucket” originate? 321 + does leather come from? 538 + do living things come from? 174 + did life begin on earth? 174 + do we get ivory? 239 + do lead pencils come from? 466 + does the wooden part of a lead pencil come from? 469 + does a light go when it goes out? 36 + does linseed oil come from? 227 + does paint come from? 224 + does the rain go? 222 + are the best Persian rugs made? 167 + does rope come from? 353 + does salt come from? 493 + do we get soda? 494 + do all the little round stones come from? 494 + does the part of a stocking go that was where the hole comes? 64 + does sound come from? 78 + do school slates come from? 495 + do shoes come from? 541 + do sponges come from? 286 + do tears come from? 94 + do the tears go? 94 + did the name tobacco originate? 512 + is Havana tobacco grown? 513 + does tobacco come from? 512 + does tobacco grow? 512 + did all the water in the ocean come from? 218 + does our drinking water come from? 501 + does most of our wool come from? 81 + does the wind begin? 139 + is the wind when it is not blowing? 139 + does wool come from? 80 + did the term Yankee originate? 243 + + =Wheat=, bread loaves of the world, 459 + grinding (illus.), 464 + harvesting (illus.), 460 + scouring of, 463 + tempering of, 463 + when first used in making bread, 461 + will it grow wild? 461 + + =Wheel-lock= rifle (illus.), 46 + + =Whispering gallery=, accidental, 201 + cause of, 201 + what it is, 201 + + =Whistle=, what makes the kettle? 198 + + =White Lead=, making (illus.), 225 + buckles, before corrosion (illus.), 225 + buckles after corrosion (illus.), 225 + buckles, making, 225 + + =Who= started to make clothing from wool in America? 81 + discovered electricity? 333 + invented electric telegraph? 420 + made the first felt hat? 239 + made the first cent? 458 + made the first submarine boat? 280 + first discovered the silkworm? 109 + first discovered the power of gunpowder? 44 + invented flying? 126 + made the first piano? 478 + brought the first sheep to America? 80 + first wove silk thread into cloth? 109 + make the first shoes? 541 + made the first umbrella? 312 + + =Why= don’t the air ever get used up? 140 + can’t we see air? 140 + do we grow aged? 196 + does an apple turn brown when cut? 106 + do coats have buttons on the sleeves? 64 + has a long coat buttons on the back? 64 + cannot babies walk as soon as born? 180 + are some people bald? 144 + don’t the birds stay South? 408 + does a ball bounce? 63 + does a balloon go up? 199 + do we call voting balloting? 122 + does a barber pole have stripes? 310 + do some things bend and others break? 62 + do the birds come back in the Spring? 407 + do birds sing? 408 + do birds go South in the Winter? 407 + are birds’ eggs of different colors? 233 + has a bee a sting? 336 + can you blow out a candle? 21, 36 + are bubbles round? 108 + does red make a bull angry? 490 + do we get a bump instead of a dent when we knock our heads? 201 + can’t we burn stones? 105 + has a long coat buttons? 64 + is bread so important? 460 + do I get out of breath when running? 191 + do we call a cab a hansom? 122 + does a hen cackle after laying an egg? 233 + do children like candy? 409 + is cement called Portland cement? 95 + do I get cold in a warm room? 125 + is it cold in winter? 141 + does cold make our hands blue? 192 + does an ear of corn have silk? 170 + do we count in tens? 10 + we cannot see in the dark, 91 + does the dark cause fear? 352 + do we have to die? 245 + does a dog turn round and round before he lies down, 229 + do we know we have dreamed when we wake up? 367 + does eating candy make some people fat? 409 + doesn’t an elevator fall? 397 + do our eyes sparkle when we are merry? 92 + do the eyes of some pictures follow us? 35 + is it difficult to walk straight with my eyes closed? 91 + do I get red in the face? 192 + are some faculties stronger than others? 403 + is a fire hot? 401 + does a fire go out? 37 + we fear the dark? 352 + cannot fishes live in air? 232 + do we have finger nails? 142 + are our fingers of different lengths? 142 + have we five fingers on each hand and five toes on each foot? 142 + do we have finger nails? 142 + does a gasoline engine go? 181 + do girls like dolls? 368 + is gold called precious? 266 + are gold and silver best for coining? 457 + is some gun-powder fine and others coarse grained? 206 + are some guns called gatling guns? 310 + does a glow-worm glow? 231 + do we stop growing? 195 + do we have hair? 143 + does the hair grow after the body stops growing? 144 + don’t my hair hurt when it is being cut? 143 + does my hair stand on end when I am frightened? 143 + is the right hand stronger than the left? 309 + does my heart beat faster when I am scared? 191 + does the heart beat when the brain is asleep? 191 + do our hearts beat faster when we are running? 191 + do they call it a honeymoon? 31 + is a horseshoe said to bring good luck? 311 + does it hurt when I cut my finger? 143 + we cry when hurt, 93 + does iron turn red when red hot? 107 + does iron sink in water? 106 + doesn’t an iron ship sink? 106 + do we have twelve men on a jury? 239 + does a lamp give a better light with the chimney on? 37 + are there many languages? 197 + do we laugh when glad? 92 + is lead so heavy? 267 + do they call them lead pencils? 466 + must life be reproduced? 174 + are some people light and others dark? 402 + did people of long ago live longer than we do now? 199 + do we use metal for coining? 456 + do they call it the milky way? 255 + do we need money? 455 + does the moon travel with us when we walk or ride? 399 + should we not sleep with the moon shining on us? 366 + do my muscles get sore when I play ball in the spring? 310 + does a nail get hot when hammered? 230 + do we have only seven octaves on a piano? 480 + does the ocean look blue at times? 219 + does oiling the axle make the wheel turn more easily? 400 + does an onion make the tears come? 38 + can’t I write on paper with a slate pencil? 18 + does a pencil write? 18 + are some races white and others black, yellow and brown? 537 + do they call it pin money? 231 + do we call them pistols? 46 + do plants produce seeds? 175 + does a poker get hot at both ends if left in the fire? 107 + does rain make the air fresh? 222 + are most people right-handed? 403 + don’t we make roads perfectly level? 104 + don’t we use pure rubber? 380 + does salt make us thirsty? 351 + don’t the scenery appear to move when I am in a street car? 399 + does the scenery appear to move when we are riding in a train? 399 + can cats and some other animals see in the dark? 91 + can we see farther when we are up high? 245 + do I turn white when scared? 193 + does silver tarnish? 266 + does the sheep precede the plow in civilizing a country? 81 + is the sky blue? 253 + do I sneeze? 194 + do we see stars when hit on eye? 268 + many stars are there? 223 + does a stick in water bend? 38 + does a sound stop when we touch a gong that has been sounded? 78 + can we make sounds with our throats? 78 + do people shake with the right hand? 231 + do we go to sleep? 365 + does it seem when we have slept all night that we have been asleep + only a minute? 366 + can’t we sleep with our eye open? 92 + we can hear through speaking tubes, 487 + does a human being have to learn to swim? 125 + are cooking utensils made of tin? 267 + do we use copper telegraph wires? 266 + do my teeth chatter? 218 + are some things transparent and others are not? 350 + do I laugh when tickled? 93 + can we think of only one thing at a time? 193 + does thunder always come after the lightning? 140 + do we call them wisdom teeth? 125 + are some roads called turnpikes? 104 + is the sea water salt? 351 + will water run off a duck’s back? 233 + do we worry? 207 + don’t the water in the ocean sink in? 219 + is it warm in summer? 141 + does water run? 219 + do we say water is soft or hard? 221 + does a piece of wood float in water? 106 + do we wake up in the morning? 365 + do I yawn? 173 + does yeast make bread rise? 288 + + =Will= people all be bald sometime? 144 + the sky ever fall down? 255 + + =Windows=, how an explosion breaks them, 62 + + =Wireless=, accidents, prevention of, 449 + aerial on R. R. stations (illus.), 451 + aerial on ship (illus.), 455 + antennæ, 447 + antennæ on trains (illus.), 450 + battery, 447 + coil, 447 + compass, 454 + development of, 454 + direction finder, 454 + distance of sending, 448 + equipment, 446 + first Marconi station, 452 + how it reaches ships at sea, 446 + icebergs (illus.), 449 + in the army (illus.), 447-448 + inventor of, 452 + key, 447 + masts, height of, 448 + G. Marconi, portrait, 452 + on trains (illus.), 450 + prevents accidents, 449 + principles of, 455 + receiving station in U. S. Army (illus.), 451 + spark gap, 447 + stations, shore (illus.), 446 + stations on trains (illus.), 450 + transmission automatic (illus.), 453 + transmission of messages (illus.), 453 + what kind of signs are used in? 446 + why don’t the message go to the wrong stations, 455 + world-wide use, 454 + + =Wires=, copper telegraph, 266 + how put underground (illus.), 76 + wire-wound gun, 54 + + =Wonders= performed by electric lift magnet (illus.), 326 + + =Wool= beaming (illus.), 89 + bobbin in weaving machine, 86 + Burling (illus.), 88 + burr picker, 87 + carding, 85 + carding, finisher in cloth making (illus.), 89 + chloride of aluminum in making cloth, 87 + cleaning, 85 + made clothing from, 81 + combing (illus.), 86 + cost of in a suit of clothes, 83 + crop of the United States, 82 + dyeing, 85-87 + fabrics, 85 + fiber description, 83 + finishing, box (illus.), 87 + finish, perching (illus.), 90 + fulling cloth (illus.), 90 + gilling after carding (illus.), 86 + gilling and making top after combing (illus.), 86 + gilling (illus.), 87 + greasy matter in, 84 + how we get it off the sheep, 82 + how much does a sheep produce, 83 + how much does America produce, 82 + how made into cloth, 85 + how woolen cloth is made perfect, 88 + how shipped, 82 + loom, 86 + mending, perching (illus.), 88 + mending room (illus.), 88 + woolen mule spinning (illus.), 89 + napping, 89 + next to food as a vital necessity, 81 + piece dyeing (illus.), 90 + quality of a hundred years ago, 83 + raised to sell to manufacturers, 81 + reducer machine in wool making (illus.), 87 + ring twisting (illus.), 89 + shipped to manufacturers, 82 + shuttle in weaving, 86 + scouring (illus.), 85 + sorting (illus.), 84 + spinning process, 86 + spinning, 89 + English cap spinning, 89 + in one suit of clothes, 83 + sulphuric acid solution in making cloth, 87 + teasel, 89 + tramper, 82 + in United States, bulk of, 82 + warp thread, 86 + web, 86 + weaving (illus.), 88 + where does most of our wool come from? 81 + woof of, 86 + made into yarn, 86 + yarn inspecting (illus.), 89 + yolk of, 84 + + =Woolen cloth=, ready for market (illus.), 90 + + =Woolens and worsteds=, difference between, 84 + + =Woolworth building= (illus.), 395 + + =Words=, formation of, 19 + the first over a telephone, 74 + + =World’s= bread loaves (illus.), 459 + + =Worry=, definition of, 207 + what it is, 207 + Why we, 207 + + =Worsted= carding (illus.), 85 + fabrics, 85 + + =Worsteds and woolens=, difference of, 84 + + =Wright Brothers=, first successful flights, 130 + + =Wrinkles=, what causes, 196 + + =Writing=, brush, the (illus.), 13 + earliest ways of, 12 + first done upon rocks, 11 + first imitation of, 12 + first metallic pen introduced, 15 + fluids for developing, 13 + how man learned to, 11 + how the monks did their, 14 + how a pen writes, 18 + modern way of, 16 + paper for, earliest, 14 + pen, invention of, 11 + pen, first steel (illus.), 15 + quill, the (illus.), 14 + Reed, the, in (illus.), 12 + steel tube pen in (illus.), 15 + steel pen, modern (illus.), 16 + Stylus, the (illus.), 11 + with chalk, 18 + why a pencil writes, 18 + + =X-rays=, what are they? 307 + + =Yankee=, where word originated, 243 + + =Yarn=, made from wool, 86 + + =Yawning=, why do, 173 + is it infectious, 192 + + =Yeast=, what it is, 288 + why it makes bread rise, 288 + + =Yes=, meaning of nod, 19 + + =Zollner, Casper=, inventor of rifling, 46 + + + + + Transcriber’s Notes + + + The language used in this ebook is that of the source document, + including unusual or archaic spelling. The book was partly written + by representatives of the industries concerned; inconsistencies in + grammar, spelling, punctuation (including the use of decimal points + and commas), style, lay-out, etc. have been retained. Contradictions + and repetitions have not been addressed. Alphabetical sorting + inconsistencies in the index have not been corrected. + + Page 218, ... and have them meet as shown in Fig. 13 ...: The + illustrations in this chapter are not numbered. The illustration on + page 215 shows the described meeting of the shields. + + Page 305, ... (as shown in Fig. 4): the illustrations with this + article are not numbered. + + Page 307, The X-rays are discharged in straight lines as shown in the + figure: there is no such figure in the book. + + Pages 328 and 330: page headings WHAT A LODESTONE IS and WHAT + ELECTRICITY IS do not relate to the contents of the pages. + + Page 336, The pictures shown on the following pages ...: as printed; + the illustrations are given on previous pages. + + Page 364, reference to figure 6: presumably the four illustrations on + this page together form figure 6. + + Page 368, When you put oil on the axle, however, ...: some text may + be missing. + + Page 376, ... or three-sixty-fourths of a second, and: as printed in + the source document; some text is obviously missing. + + Page 489, ... of much importance. The two classes, only two of which + are of much importance. The two classes ...: the redundant text is as + printed in the source document. + + Page 491: There is no Fig. 4 in the source document; the unnumbered + figure in the bottom right of the page is assumed to be Fig. 4. + + Page 502, captions with bottom illustration: at least one of the + lengths given (4650 and 4560 feet) is likely to be a typographical + error. + + Page 547, (The welt shoe has always been considered ...: the closing + bracket is lacking. + + + Changes made: + + Some minor obvious punctuation and typographical errors and + unnecessarily repeated words have been corrected silently. + + Illustrations have been moved out of text paragraphs. Page + headers have been transcribed as illustration captions (on top + of illustrations) or as side notes at a suitable location on the + page concerned, so that their reference in the index is (at least + approximately) correct. + + Text that was not present as such in the source document but that + was transcribed from within illustrations is given as part of the + illustration caption. + + Page 29: ... never see the distance target or vessel ... changed to + ... never see the distant target or vessel .... + + Page 46: Lock á là Miquelet changed to Lock à la Miquelet. + + Pages 74-75: closing double quotes inserted after ... went that very + night.; ... had to look after it themselves.; ... speech had really + been electrically reproduced. Opening double quotes inserted before + Now, it so happened there, ...; My friend, Mr. William Hubbard, .... + + Page 114: ... the white mulberry or osage orange are fed the young + worms ... changed to ... the white mulberry or osage orange are fed + the young worm .... + + Page 124: ... called an ablate spheroid ... changed to ... called an + oblate spheroid .... + + Page 126: Dr. Samuel Pierrpont Langley changed to Dr. Samuel Pierpont + Langley. + + Page 167: ... against the loose row of cross threads to lighten it + ... changed to ... against the loose row of cross threads to tighten + it .... + + Page 205: ... than the heat will cause the air to expand suddenly ... + changed to ... that the heat will cause the air to expand suddenly + ...; ... a mixture of potassium, nitrate, or saltpeter, with powdered + charcoal and phur ... changed to ... a mixture of potassium nitrate, + or saltpeter, with powdered charcoal and sulphur .... + + Page 229: ... other machines called Mills,” ... changed to ... other + machines called “Mills,” ....; ... which also adds in the drying and + the working ... changed to ... which also aids in the drying and the + working .... + + Page 265: ... there is another, solium, which is solid ... changed to + ... there is another, sodium, which is solid ...; ... what is called + a reverbratory furnace ... changed to what is called a reverberatory + furnace .... + + Page 292: PROMOTHEAN MATCH changed to PROMETHEAN MATCH. + + Page 375: This toy we speak of was called a zoctrope changed to This + toy we speak of was called a zoetrope. + + Page 376: ... projected at the rate of fourteen or sixteen to the + minute ... changed to ... projected at the rate of fourteen or + sixteen to the second .... + + Page 377: Footnote anchor [4] inserted. + + Page 414 ff.: Ellipses (...) have been added surrounding the + continuing page headings and illustration captions. + + Pages 419 and 438, Morse codes: for the sake of clarity, the spacing + between individual dashes and dots has been increased slightly. + + Page 490: ... if a red flag really makes a bull more exited ... + changed to ... if a red flag really makes a bull more excited .... + + Page 493: The chemical name for salt is sodium which is derived ... + changed to The chemical name for salt is sodium chloride which is + derived ...; ... substances around us are composed of these elements + along, or ... changed to ... substances around us are composed of + these elements alone, or .... + + Page 550: ... for which the lingings were intended. After all the + lingings have been prepared ... changed to ... for which the linings + were intended. After all the linings have been prepared .... + + Index: several missing punctuation marks inserted for consistency. + + Page 583: Curtis biplane changed to Curtiss biplane. + + Page 585: Burline (illus.) changed to Burling (illus.) + + Page 586: Culverines, early type of changed to Culverins, early type + of. + + Page 587: steal and flint changed to steel and flint. + + Page 588: Flying boot, interior arrangement changed to Flying boat, + interior arrangement. + + Page 589: (How) the pictures in this both are made changed to (How) + the pictures in this book are made. + + Page 590: (How) did shaking the head come to come no? changed to + (How) did shaking the head come to mean no?; (How) does does the wool + in a suit of clothes cost? changed to (How) much does the wool in a + suit of clothes cost?; Hurt, why we cry changed to Hurt, why we cry + when, 93. + + Page 591: the “Reverbere” changed to the “Réverbère”; (Lamp) from + Nashagak hanging changed to (Lamp) from Nushagak hanging. + + Page 592: promothean changed to promethean. + + Page 593: Kurdestan (illus.) changed to Kurdistan (illus.). + + Page 595: Crakron or peaked changed to Crakrow or peaked. + + Page 597: omniscope changed to Omniscope; cucular diffusion battery + in factory changed to circular diffusion battery in factory. + + Page 601: (Who) who make the first felt hat? changed to (Who) made + the first felt hat?; (Why) don’t an elevator fall? changed to (Why) + doesn’t an elevator fall? + + Page 603: (Writing) pen invention of, 00 changed to (Writing) pen, + invention of, 11. + + + +*** END OF THE PROJECT GUTENBERG EBOOK 75948 *** |