BOYS' SECOND BOOK OF
INVENTIONS

BOYS' SECOND BOOK
OF INVENTIONS

BY RAY STANNARD BAKER
Author of
Boys' Book of Inventions, Seen in
Germany

FULLY ILLUSTRATED

NEW YORK
DOUBLEDAY, PAGE & COMPANY
MCMIX

Copyright, 1903, by
McCLURE, PHILLIPS & CO.
Published, November, 1903, N

TABLE OF CONTENTS

LIST OF ILLUSTRATIONS

BOYS' SECOND BOOK OF
INVENTIONS

CHAPTER I
THE MIRACLE OF RADIUM
Story of the Marvels and Dangers of the New Element Discovered by Professor and Madame Curie

No substance ever discovered better deserves the term "Miracle of Science," given it by a famous English experimenter, than radium. Here is a little pinch of white powder that looks much like common table salt. It is one of many similar pinches sealed in little glass tubes and owned by Professor Curie, of Paris. If you should find one of these little tubes in the street you would think it hardly worth carrying away, and yet many a one of them could not be bought for a small fortune. For all the radium in the world to-day could be heaped on a single table-spoon; a pound of it would be worth nearly a million dollars, or more than three thousand times its weight in pure gold.

Professor and Madame Curie, who discovered radium, now possess the largest amount of any one, but there are small quantities in the hands of English and German scientists, and perhaps a dozen specimens in America, one owned by the American Museum of Natural History and several by Mr. W. J. Hammer, of New York, who was the first American to experiment with the rare and precious substance.

M. Curie Explaining the Wonders of Radium at the Sorbonne.

And perhaps it is just as well, at first, not to have too much radium, for besides being wonderful it is also dangerous. If a pound or two could be gathered in a mass it would kill every one who came within its influence. People might go up and even handle the white powder without at the moment feeling any ill-effects, but in a week or two the mysterious and dreadful radium influence would begin to take effect. Slowly the victim's skin would peel off, his body would become one great sore, he would fall blind, and finally die of paralysis and congestion of the spinal cord. Even the small quantities now in hand have severely burned the experimenters. Professor Curie himself has a number of bad scars on his hands and arms due to ulcers caused by handling radium. And Professor Becquerel, in journeying to London, carried in his waistcoat pocket a small tube of radium to be used in a lecture there. Nothing happened at the time, but about two weeks later Professor Becquerel observed that the skin under his pocket was beginning to redden and fall away, and finally a deep and painful sore formed there and remained for weeks before healing.

It is just as well, therefore, that scientists learn more about radium and how to handle and control it before too much is manufactured.

But the cost and danger of radium are only two of its least extraordinary features. Seen in the daylight radium is a commonplace white powder, but in the dark it glows like live fire, and the purer it is the more it glows. I held for a moment one of Mr. Hammer's radium tubes, and, the lights being turned off, it seemed like a live coal burning there in my hand, and yet I felt no sensation of heat. But radium really does give off heat as well as light—and gives it off continually without losing appreciable weight. And that is what seems to scientists a miracle. Imagine a coal which should burn day in and day out for hundreds of years, always bright, always giving off heat and light, and yet not growing any smaller, not turning to ashes. That is the almost unbelievable property of radium. Professor Curie has specimens which have thus been radiating light and heat for several years, with practically no loss of weight; and no small amount of light and heat either. Professor Curie has found that a given quantity of radium will melt its own weight of ice every hour, and continue doing so practically for ever. One of his associates has calculated that a fixed quantity of radium, after throwing out heat for 1,000,000,000 years, would have lost only one-millionth part of its bulk.

What is the reason for these extraordinary properties? Is it not "perpetual motion"? All the great scientists of the world have been trying in vain to answer these questions. Several theories have been advanced, of which I shall speak later, but none seems a satisfactory explanation. When we know more of radium perhaps we shall be better prepared to say what it really is, and we may have to unlearn many of the great principles of physics and chemistry which were seemingly settled for all time. Radium would seem, indeed, to defy the very law of the conservation of energy.

The practical mind at once sees radium in use as a new source of heat and light for mankind, a furnace that would never have to be fed or cleaned, a lamp that would glow perpetually—and the time may really come, the inventor having taken hold of the wonder that the scientist has produced, when many practical applications of the new element may be devised. At present, however, the scarcity and cost and danger of radium will keep it in the hands of the experimenter.

Another astonishing property of radium is its power of communicating some of its strange qualities to certain substances brought within its influence. Mr. Hammer kept his radium tubes for a time in a pasteboard box. This being broken, he removed the tubes and threw the pasteboard aside. Several days later, having occasion to turn off the lights in the laboratory, he found that the discarded box was glowing there in the dark. It had taken up some of the rays from the radium. Nearly everything that comes in contact with radium thus becomes "radio-active"—even the experimenter's clothes and hands, so that delicate instruments are disturbed by the invisible shine of the experimenter. Photographs can be taken with radium; it also makes the air around it a better conductor of electricity. And still more marvellous, besides being an agency for the destruction of life, as I shall show later, it can actually be used in other ways to prolong life, and the future may show many wonderful uses for it in the treatment of disease. Already, in Paris, several cases of lupus have been cured with it, and there is evidence that it will help to restore sight in certain cases of blindness. I held a tube of radium to my closed eye and was conscious of the sensation of light; the same sensation was present when the tube was held to my temple, thus showing that the radium has an effect on the optic nerve. A little blind girl in New York, who had never had the sensation of light, began to see a little after one treatment with radium, and experiments are still going on, but cautiously, for fear that injuries may result.

We now come to the fascinating story of the discovery and manufacture of radium. It has long been known that certain substances are phosphorescent; that is, under the proper conditions they glow without apparent heat. Everybody has seen "fox-fire" in the damp and decaying woods—a cold light which scientists have never been able to explain.

To M. Henri Becquerel of the French Institute is generally given the credit for having begun the real study of radio-activity, although, as in every great discovery and invention, many other scientists and practical electricians had paved the way by their investigations. In 1896 M. Becquerel was conducting some experiments with various phosphorescent substances. He exposed some salts of the metal uranium to the sunlight until they became phosphorescent, and then tried their effect upon a photographic plate.

It rained, and he put the plate away in a drawer for several days. When he developed it he was surprised to find on it a better image than sunlight would have made. And thus, by a sort of accident, he led up to the discovery of the Becquerel rays, so called.

Uranium is extracted from a metal or ore called uranite by mineralogists, and popularly known as pitch-blende. Every young college student who has studied geology or chemistry has heard of pitch-blende.

Two years after Becquerel's discovery of the radio-activity of uranium Professor Pierre Curie and Madame Curie, of Paris, made the discovery that some of the samples of pitch-blende which they had were much more powerful than any uranium that they had used.

Was there, then, something more powerful than uranium within the pitch-blende? They began to "boil down" the waste rock left at the uranium mines, and found a strange new element, related to uranium but different, to which Madame Curie gave the name polonium, after her native land, Poland.

Dr. Danlos Treating a Lupus Patient with Radium at the St. Louis Hospital, Paris.

Then they did some more boiling down, and succeeded in isolating an entirely new substance, and the most radio-active yet discovered—radium. Shortly after that Debierne discovered still another radio-active substance, to which he gave the name actinium.

Thus three new elements were added to the list of the world's substances, and the most wonderful of these is radium. In a day, almost, the Curies became famous in the scientific world, and many of the greatest investigators in the world—Lord Kelvin, Sir William Crookes, and others—took up the study of radium.

Very rarely have a man and woman worked together so perfectly as Professor Curie and his wife. Madame Curie was a Polish girl; she came to Paris to study, very poor, but possessed of rare talents. Her marriage with M. Curie was such a union as must have produced some fine result. Without his scientific learning and vivid imagination it is doubtful if radium would ever have been dreamed of, and without her determination and patience against detail it is likely the dream would never have been realised.

One of the chief problems to be met in finding the secrets of radium is the great difficulty and expense, in the first place, of getting any of the substance to experiment with. The Curies have had to manufacture all they themselves have used. In the first place, pitch-blende, which closely resembles iron in appearance, is not plentiful. The best of it comes from Bohemia, but it is also found in Saxony, Norway, Egypt, and in North Carolina, Colorado, and Utah. It appears in small lumps in veins of gold, silver, and mica, and sometimes in granite.

Comparatively speaking, it is easy to get uranium from pitch-blende. But to get the radium from the residues is a much more complicated task. According to Professor Curie, it is necessary to refine about 5,000 tons of uranium residues to get a kilogramme—or about 2.2 pounds—of radium.

It is hardly surprising, therefore, considering the enormous amount of raw material which must be handled, that the cost of this rare mineral should be high. It has been said that there is more gold in sea-water than radium in the earth. Professor Curie has an extensive plant at Ivry, near Paris, where the refuse dust brought from the uranium mines is treated by complicated processes, which finally yield a powder or crystals containing a small amount of radium. These crystals are sent to the laboratory of the Curies where the final delicate processes of extraction are carried on by the professor and his wife.

And, after all, pure metallic radium is not obtained. It could be obtained, and Professor Curie has actually made a very small quantity of it, but it is unstable, immediately oxidised by the air and destroyed. So it is manufactured only in the form of chloride and bromide of radium. The "strength" of radium is measured in radio-activity, in the power of emitting rays. So we hear of radium of an intensity of 45 or 7,000 or 300,000. This method of measurement is thus explained. Taking the radio-activity of uranium as the unit, as one, then a certain specimen of radium is said to be 45 or 7,000 or 300,000 times as intense, to have so many times as much radio-activity. The radium of highest intensity in this country now is 300,000, but the Curies have succeeded in producing a specimen of 1,500,000 intensity. This is so powerful and dangerous that it must be kept wrapped in lead, which has the effect of stopping some of the rays. Rock-salt is another substance which hinders the passage of the rays.

English scientists have devised a curious little instrument, called the spinthariscope, which allows one actually to see the emanations from radium and to realise as never before the extraordinary atomic disintegration that is going on ceaselessly in this strange metal. The spinthariscope is a small microscope that allows one to look at a tiny fragment of radium supported on a little wire over a screen.

Radium as a Test for Real Diamonds.

At the approach of Radium pure gems are thrown into great brilliancy, while imitations remain dull.

The experiment must be made in a darkened room after the eye has gradually acquired its greatest sensitiveness to light. Looking intently through the lenses the screen appears like a heaven of flashing meteors among which stars shine forth suddenly and die away. Near the central radium speck the fire-shower is most brilliant, while toward the rim of the circle it grows fainter. And this goes on continuously as the metal throws off its rays like myriads of bursting, blazing stars. M. Curie has spoken of this vision, really contained within the area of a two-cent piece, as one of the most beautiful and impressive he ever witnessed; it was as if he had been allowed to assist at the birth of a universe. Radium emits radiations, that is, it shoots off particles of itself into space at such terrific speed that 92,500 miles a second is considered a small estimate. Yet, in spite of the fact that this waste goes on eternally and at such enormous velocity, the actual loss sustained by the radium is, as I have said, infinitesimal.

We now come to one of the most interesting phases of the whole subject of radium—that is, the influence which its strange rays have upon animal life. Mr. Cleveland Moffett, to whom I am indebted for the facts of the following experiments, recently visited M. Danysz, of the Pasteur Institute in Paris, who has made some wonderful investigations in this branch of science. M. Danysz has tried the effect of radium on mice, rabbits, guinea-pigs, and other animals, and on plants, and he found that if exposed long enough they all died, often first losing their fur and becoming blind.

But the most startling experiment performed thus far at the Pasteur Institute is one undertaken by M. Danysz, February 3, 1903, when he placed three or four dozen little larvæ that live in flour in a glass flask, where they were exposed for a few hours to the rays of radium. He placed a like number of larvæ in a control-flask, where there was no radium, and he left enough flour in each flask for the larvæ to live upon. After several weeks it was found that most of the larvæ in the radium flask had been killed, but that a few of them had escaped the destructive action of the rays by crawling away to distant corners of the flask, where they were still living. But they were living as larvæ, not as moths, whereas in the natural course they should have become moths long before, as was seen by the control-flask, where the larvæ had all changed into moths, and these had hatched their eggs into other larvæ, and these had produced other moths. All of which made it clear that the radium rays had arrested the development of these little worms.

More weeks passed, and still three or four of the larvæ lived, and four full months after the original exposure one larva was still alive and wriggling, while its contemporary larvæ in the other jar had long since passed away as aged moths, leaving generations of moths' eggs and larvæ to witness this miracle, for here was a larva, venerable among his kind, that had actually lived through three times the span of life accorded to his fellows and that still showed no sign of changing into a moth. It was very much as if a young man of twenty-one should keep the appearance of twenty-one for two hundred and fifty years!

Not less remarkable than these are some recent experiments made by M. Bohn at the biological laboratories of the Sorbonne, his conclusions being that radium may so far modify various lower forms of life as to actually produce new species of "monsters," abnormal deviations from the original type of the species. Furthermore, he has been able to accomplish with radium what Professor Loeb did with salt solutions—that is, to cause the growth of unfecundated eggs of the sea-urchin, and to advance these through several stages of their development. In other words, he has used radium to create life where there would have been no life but for this strange stimulation.

So much for the wonders of radium. We seem, indeed, to be on the border-land of still more wonderful discoveries. Perhaps these radium investigations will lead to some explanation of that great question in science, "What is electricity?"—and that, who can say, may solve that profounder problem, "What is life?"

At present there are two theories as to the source of energy in radium, thus stated by Professor Curie:

"Where is the source of this energy? Both Madame Curie and myself are unable to go beyond hypotheses; one of these consists in supposing the atoms of radium evolving and transforming into another simple body, and, despite the extreme slowness of that transformation, which cannot be located during a year, the amount of energy involved in that transformation is tremendous.

M. and Mme. Curie Finishing the Preparation of some Radium.

"The second hypothesis consists in the supposition that radium is capable of capturing and utilising some radiations of unknown nature which cross space without our knowledge."

CHAPTER II
FLYING MACHINES [1]
Santos-Dumont's Steerable Balloons

Among the inventors engaged in building flying machines the most famous, perhaps, is M. Santos-Dumont, whose thrilling adventures and noteworthy successes have given him world-wide fame. He was the first, indeed, to build a balloon that was really steerable with any degree of certainty, winning a prize of $20,000 for driving his great air-ship over a certain specified course in Paris and bringing it back to the starting-point within a specified time. Another experimenter who has had some degree of success is the German, Count Zeppelin, who guided a huge air-ship over Lake Geneva, Switzerland, in 1901.

Carl E. Myers, an American, an expert balloonist, has also built balloons of small size which he has been able to steer. And mention must also be made of M. Severo, the Frenchman, whose ship, Pax, exploded in the air on its first trip, dropping the inventor and his assistant hundreds of feet downward to their death on the pavements of Paris.

It will be most interesting and instructive to consider especially the work of Santos-Dumont, for he has been not only the most successful in making actual flights of any of the inventors who have taken up this great problem of air navigation, but his adventures have been most romantic and thrilling. In five years' time he has built and operated no fewer than ten great air-ships which he has sailed in various parts of Europe and in America. He has even crowned his experiences with more than one shipwreck in the air, an adventure by the side of which an ordinary sea-wreck is tame indeed, and he has escaped with his life as a result not only of good fortune but of real daring and presence of mind in the face of danger.

M. Alberto Santos-Dumont.

For an inventor, M. Santos-Dumont is a rather extraordinary character. The typical inventor—at least so we think—is poor, starts poor at least, and has a struggle to rise. M. Santos-Dumont has always had plenty of means. The inventor is always first a dreamer, we think. M. Santos-Dumont is first a thoroughly practical man, an engineer with a good knowledge of science, to which he adds the imagination of the inventor and the keen love and daring of the sportsman and adventurer, without which his experiments could never have been carried through.

It would seem, indeed, that nature had especially equipped M. Santos-Dumont for his work in aërial navigation. Supposing an inventor, having all the mental equipment of Santos-Dumont, the ideas, the energy, the means—supposing such a man had weighed two hundred pounds! He would have had to build a very large ship to carry his own weight, and all his problems would have been more complex, more difficult. Nature made Santos-Dumont a very small, slim, slight man, weighing hardly more than one hundred pounds, but very active and muscular. The first time I ever saw him, in Crystal Palace, London, where he was setting up one of his air-ships in a huge gallery, I thought him at first glance to be some boy, a possible spectator, who was interested in flying machines. His face, bare and shaven, looked youthful; he wore a narrow-brimmed straw hat and was dressed in the height of fashion. One would not have guessed him to be the inventor. A moment later he had his coat off and was showing his men how to put up the great fan-like rudder of the ship which loomed above us like some enormous Rugby football, and then one saw the power that was in him. Brazilian by nationality, he has a dark face, large dark eyes, an alertness of step and an energetic way of talking. His boyhood was spent on his father's extensive coffee plantation in Brazil; his later years mostly in Paris, though he has been a frequent visitor to England and America. He speaks Spanish, French, and English with equal fluency. Indeed, hearing his English one would say that he must certainly have had his training in an English-speaking country, though no one would mistake him in appearance for either English or American, for he is very much a Latin in face and form. One finds him most unpretentious, modest, speaking freely of his inventions, and yet never taking to himself any undue credit.

Severo's Balloon, the "Pax," which, on its First Ascent at a Height of about 2,000 feet, Burst and Exploded, Sending to a Terrible Death both M. Severo and his Assistant.

Santos-Dumont is still a very young man to have accomplished so much. He was born in Brazil, July 20, 1873. From his earliest boyhood he was interested in kites and dreamed of being able to fly. He says:

"I cannot say at what age I made my first kites; but I remember how my comrades used to tease me at our game of 'Pigeon flies'! All the children gather round a table, and the leader calls out: 'Pigeon flies! Hen flies! Crow flies! Bee flies!' and so on; and at each call we were supposed to raise our fingers. Sometimes, however, he would call out: 'Dog flies! Fox flies!' or some other like impossibility, to catch us. If any one should raise a finger, he was made to pay a forfeit. Now my playmates never failed to wink and smile mockingly at me when one of them called 'Man flies!' For at the word I would always lift my finger very high, as a sign of absolute conviction; and I refused with energy to pay the forfeit. The more they laughed at me, the happier I was."

Of course he read Jules Verne's stories and was carried away in imagination in that author's wonderful balloons and flying machines. He also devoured the history of aërial navigation which he found in the works of Camille Flammarion and Wilfrid de Fonvielle. He says, further:

"At an early age I was taught the principles of mechanics by my father, an engineer of the École Centrale des Arts et Manufactures of Paris. From childhood I had a passion for making calculations and inventing; and from my tenth year I was accustomed to handle the powerful and heavy machines of our factories, and drive the compound locomotives on our plantation railroads. I was constantly taken up with the desire to lighten their parts; and I dreamed of air-ships and flying machines. The fact that up to the end of the nineteenth century those who occupied themselves with aërial navigation passed for crazy, rather pleased than offended me. It is incredible and yet true that in the kingdom of the wise, to which all of us flatter ourselves we belong, it is always the fools who finish by being in the right. I had read that Montgolfière was thought a fool until the day when he stopped his insulters' mouths by launching the first spherical balloon into the heavens."

The Trial of Count Zeppelin's Air-Ship, July 2, 1900.

Upon going to Paris Santos-Dumont at once took up the work of making himself familiar with ballooning in all of its practical aspects. He saw that if he were ever to build an air-ship he must first know all there was to know about balloon-making, methods of filling with gas, lifting capacities, the action of balloons in the air, and all the thousand and one things connected with ordinary ballooning. And Paris has always been the centre of this information. He regards this preliminary knowledge as indispensable to every air-ship builder. He says:

"Before launching out into the construction of air-ships I took pains to make myself familiar with the handling of spherical balloons. I did not hasten, but took plenty of time. In all, I made something like thirty ascensions; at first as a passenger, then as my own captain, and at last alone. Some of these spherical balloons I rented, others I had constructed for me. Of such I have owned at least six or eight. And I do not believe that without such previous study and experience a man is capable of succeeding with an elongated balloon, whose handling is so much more delicate. Before attempting to direct an air-ship, it is necessary to have learned in an ordinary balloon the conditions of the atmospheric medium; to have become acquainted with the caprices of the wind, now caressing and now brutal, and to have gone thoroughly into the difficulties of the ballast problem, from the triple point of view of starting, of equilibrium in the air, and of landing at the end of the trip. To go up in an ordinary balloon, at least a dozen times, seems to me an indispensable preliminary for acquiring an exact notion of the requisites for the construction and handling of an elongated balloon, furnished with its motor and propeller."

M. Santos-Dumont at Nineteen.

M. Santos-Dumont's First Balloon (Spherical).

His first ascent in a balloon was made in 1897, when he was 24 years old, as a passenger with M. Machuron, who had then just returned from the Arctic regions, where he had helped to start Andrée on his ill-fated voyage in search of the North Pole. He found the sensations delightful, being so pleased with the experience that he subsequently secured a small balloon of his own, in which he made several ascents. He also climbed the Alps in order to learn more of the condition of the air at high altitudes.

In 1898 he set about experimentation in the building of a real air-ship or steerable balloon. Efforts had been made in this direction by former inventors, but with small success. As far back as 1852 Henri Gifford made the first of the familiar cigar-shaped balloons, trying steam as a motive power, but he soon found that an engine strong enough to propel the balloon was too heavy for the balloon to lift. That simple failure discouraged experimenters for a long time. In 1877 Dupuy de Lome tried steering a balloon by man power, but the man was not strong enough. In 1883 another Frenchman, Tissandier, experimented with electricity, but, as his batteries had to be light enough to be taken up in the balloon, they proved effective only in helping to weigh it down to earth again. Krebs and Renard, military aëronauts, succeeded better with electricity, for they could make a small circuit with their air-ship, provided only that no air was stirring. Enthusiasts cried out that the problem was solved, but the two aëronauts themselves, as good mathematicians, figured out that they would have to have a motor eight times more powerful than their own, and that without any increase in weight, which was an impossibility at that time.

M. Santos-Dumont's Workshop.

Santos-Dumont saw plainly that none of these methods would work. What then was he to try? Why, simple enough: the petroleum motor from his automobile. The recent development of the motor-vehicle had produced a light, strong, durable motor. It was Santos-Dumont's first great claim to originality that he should have applied this to the balloon. He discovered no new principles, invented nothing that could be patented. The cigar-shaped balloon had long been used, so had the petroleum motor, but he put them together. And he did very much more than that. The very essence of success in aërial navigation is to secure light weight with great strength and power. The inventor who can build the lightest machine, which is also strong, will, other things being equal, have the greatest success. It is to Santos-Dumont's great credit that he was able to build a very light motor, that also gave a good horse-power, and a light balloon that was also very strong. The one great source of danger in using the petroleum motor in connection with a balloon is that the sparking of the motor will set fire to the inflammable hydrogen gas with which the balloon is filled, causing a terrible explosion. This, indeed, is what is thought to have caused the mortal mishap to Severo and his balloon. But Santos-Dumont was able to surmount this and many other difficulties of construction.

The inventor finally succeeded in making a motor—remarkable at that time—which, weighing only 66 pounds, would produce 3½ horse-power. It is easy to understand why a petroleum motor is such a power-producer for its size. The greater part of its fuel is in the air itself, and the air is all around the balloon, ready for use. The aëronaut does not have to take it up with him. That proportion of his fuel that he must carry, the petroleum, is comparatively insignificant in weight. A few figures will prove interesting. Two and one-half gallons of gasoline, weighing 15 pounds, will drive a 2½ horse-power autocycle 94 miles in four hours. Santos-Dumont's balloon needs less than 5⅓ gallons for a three hours' trip. This weighs but 37 pounds, and occupies a small cigar-shaped brass reservoir near the motor of his machine. An electric battery of the same horse-power would weigh 2,695 pounds.

"Santos-Dumont No. 1."

Santos-Dumont tested his new motor very thoroughly by attaching it to a tricycle with which he made some record runs in and around Paris. Having satisfied himself that it was thoroughly serviceable he set about making the balloon, cigar-shaped, 82 feet long.

"To keep within the limit of weight," he says, "I first gave up the network and the outer cover of the ordinary balloon. I considered this sort of second envelope, holding the first within it, to be superfluous, and even harmful, if not dangerous. To the envelope proper I attached the suspension-cords of my basket directly, by means of small wooden rods introduced into horizontal hems, sewed on both sides along the stuff of the balloon for a great part of its length. Again, in order not to pass the 66 pounds weight, including varnish, I was obliged to choose Japan silk that was extremely fine, but fairly resisting. Up to this time no one had ever thought of using this for balloons intended to carry up an aëronaut, but only for little balloons carrying light registering apparatus for investigations in the upper air.

Basket of "Santos-Dumont No. 1."

Showing propeller and motor.

"I gave the order for this balloon to M. Lachambre. At first he refused to take it, saying that such a thing had never been made, and that he would not be responsible for my rashness. I answered that I would not change a thing in the plan of the balloon, if I had to sew it with my own hands. At last he agreed to sew and varnish the balloon as I desired."

After repeated trials of his motor in the basket—which he suspended in his workshop—and the making of a rudder of silk he was able, in September, 1898, to attempt real flying. But, after rising successfully in the air, the weight of the machinery and his own body swung beneath the fragile balloon was so great that while descending from a considerable height the balloon suddenly sagged down in the middle and began to shut up like a portfolio.

"At that moment," he said, "I thought that all was over, the more so as the descent, which had already become rapid, could no longer be checked by any of the usual means on board, where nothing worked.

"Santos-Dumont No. 1."

Showing how it began to fold up in the middle.

"The descent became a rapid fall. Luckily, I was falling in the neighborhood of the soft, grassy pélouse of the Longchamps race-course, where some big boys were flying kites. A sudden idea struck me. I cried to them to grasp the end of my 100-meter guide-rope, which had already touched the ground, and to run as fast as they could with it against the wind! They were bright young fellows, and they grasped the idea and the guide-rope at the same lucky instant. The effect of this help in extremis was immediate, and such as I had expected. By this manœuvre we lessened the velocity of the fall, and so avoided what would otherwise have been a terribly rough shaking up, to say the least. I was saved for the first time. Thanking the brave boys, who continued to aid me to pack everything into the air-ship's basket, I finally secured a cab and took the relic back to Paris."

His life was thus saved almost miraculously; but the accident did not deter him from going forward immediately with other experiments. The next year, 1899, he built a new air-ship called Santos-Dumont II., and made an ascension with it, but it dissatisfied him and he at once began with Santos-Dumont III., with which he made the first trip around the Eiffel Tower.

He now made ready to compete for the Deutsch prize of $20,000. The winning of this prize demanded that the trip from Saint-Cloud to the Eiffel Tower, around it and back to the starting place, a distance of some eight miles, should be made in half an hour. For this purpose he finished a much larger air-ship, Santos-Dumont V., in 1901. After a trial, made on July 12, which was attended by several accidents, the inventor decided to make a start early on the following morning, July 13. As early as four o'clock he was ready, and a crowd had begun to gather in the park.

At 6.20 the great sliding doors of the balloon-house were pushed open, and the massive inflated occupant was towed out into the open space of the park. The big pointed nose of the balloon and its fish-like belly resembled a shark gliding with lazy craft from a shadow into light waters. In the basket of the car stood the coatless aëronaut, who laughed and chatted like a boy with the crowd around him.

"Santos-Dumont No. 5" Rounding Eiffel Tower, July 13, 1901.

From the very first the conditions did not show themselves favourable for the attempt. The wind was blowing at the rate of six or seven yards a second. The change of temperature from the balloon-house to the cool morning air had somewhat condensed the hydrogen gas of the balloon, so that one end flapped about in a flabby manner. Air was pumped into the air reservoir, inside the balloon, but still the desired rigidity was not attained. But, more discouraging yet, when the motor was started, its continuous explosions gave to the practised ear signs of mechanical discord.

Nevertheless, Santos-Dumont, with his sleeves rolled up, fixed himself in his basket. His eye took a careful survey of the entire air-ship lest some preliminary had been overlooked. He counted the ballast bags under his feet in the basket, he looked to the canvas pocket of loose sand at either hand, then saw to his guide-rope.

There is a very great deal to look after in managing such a ship, and it requires a calm head and a steady hand to do it.

"Near the saddle on which I sat," he writes, "were the ends of the cords and other means for controlling the different parts of the mechanism—the electric sparking of the motor, the regulation of the carburetter, the handling of the rudder, ballast, and the shifting weights (consisting of the guide-rope and bags of sand), the managing of the balloon's valves, and the emergency rope for tearing open the balloon. It may easily be gathered from this enumeration that an air-ship, even as simple as my own, is a very complex organism; and the work incumbent on the aëronaut is no sinecure."

Several friends shook his hand, among them Mr. Deutsch. The place was very still as the man holding the guide-rope awaited the signal to let go. Then the little man in the basket above them raised his hands and shouted.

The Interior of the Aërodrome.

Showing its construction, the inflated balloon, and the pennant with its mystic letters.

At first it did not look like a race against time. The balloon rose sluggishly, and Santos-Dumont had to dump out bag after bag of sand, till finally the guide-rope was clear of the trees. All this gave him no opportunity to think of his direction, and he was drifting toward Versailles; but while yet over the Seine he pulled his rudder ropes taut. Then slowly, gracefully, the enormous spindle veered round and pointed its nose toward the Eiffel Tower. The fans spun energetically, and the air-ship settled down to business-like travelling. It marked a straight, decided line for its goal, then followed the chosen route with a considerable speed. Soon the chug-chugging of the motor could be heard no longer by the spectators, and the balloon and car grew smaller and smaller in its halo of light smoke. Those in the park saw only the screw and the rear of the balloon, like the stern of a steamer in dry dock. Before long only a dot remained against the sky. Gradually he came nearer again, almost returning to the park, but the wind drove him back across the river Seine. Suddenly the motor stopped, and the whole air-ship was seen to fall heavily toward the earth. The crowd raced away expecting to find Santos-Dumont dead and his air-ship a wreck. But they found him on his feet, with his hands in his pockets, reflectively looking up at his air-ship among the top branches of some chestnut trees in the grounds of Baron Edmund de Rothschild, Boulevard de Boulogne.

"This," he says, "was near the hôtel of Princesse Ysabel, Comtesse d'Eu, who sent up to me in my tree a champagne lunch, with an invitation to come and tell her the story of my trip.

"When my story was over, she said to me:

"'Your evolutions in the air made me think of the flight of our great birds of Brazil. I hope that you will succeed for the glory of our common country.'"

And an examination showed that the air-ship was practically uninjured.

So he escaped death a second time. Less than a month later he had a still more terrible mishap, best related in his own words. He says:

"And now I come to a terrible day—August 8, 1901. At 6.30 A.M., I started for the Eiffel Tower again, in the presence of the committee, duly convoked. I turned the goal at the end of nine minutes, and took my way back to Saint-Cloud; but my balloon was losing hydrogen through the automatic valves, the spring of which had been accidentally weakened; and it shrank visibly. All at once, while over the fortifications of Paris, near La Muette, the screw-propeller touched and cut the suspension-cords, which were sagging behind. I was obliged to stop the motor instantly; and at once I saw my air-ship drift straight back to the Eiffel Tower. I had no means of avoiding the terrible danger, except to wreck myself on the roofs of the Trocadero quarter. Without hesitation I opened the manœuvre-valve, and sent my balloon downward.

The Fall into the Courtyard of the Trocadero Hotel.

"Santos-Dumont No. 5."

"At 32 metres (106 feet) above the ground, and with the noise of an explosion, it struck the roof of the Trocadero Hotels. The balloon-envelope was torn to rags, and fell into the courtyard of the hotels, while I remained hanging 15 metres (50 feet) above the ground in my wicker basket, which had been turned almost over, but was supported by the keel. The keel of the Santos-Dumont V. saved my life that day.

"After some minutes a rope was thrown down to me; and, helping myself with feet and hands up the wall (the few narrow windows of which were grated like those of a prison), I was hauled up to the roof. The firemen from Passy had watched the fall of the air-ship from their observatory. They, too, hastened to the rescue. It was impossible to disengage the remains of the balloon-envelope and suspension apparatus except in strips and pieces.

"My escape was narrow; but it was not from the particular danger always present to my mind during this period of my experiments. The position of the Eiffel Tower as a central landmark, visible to everybody from considerable distances, makes it a unique winning-post for an aërial race. Yet this does not alter the other fact that the feat of rounding the Eiffel Tower possesses a unique element of danger. What I feared when on the ground—I had no time to fear while in the air—was that, by some mistake of steering, or by the influence of some side-wind, I might be dashed against the Tower. The impact would burst my balloon, and I should fall to the ground like a stone. Though I never seek to fly at a great height—on the contrary, I hold the record for low altitude in a free balloon—in passing over Paris I must necessarily move above all its chimney-pots and steeples. The Eiffel Tower was my one danger—yet it was my winning-post!

"Santos-Dumont No. 6"—The Prize Winner.

"But in the air I have no time to fear. I have always kept a cool head. Alone in the air-ship, I am always very busy. I must not let go the rudder for a single instant. Then there is the strong joy of commanding. What does it feel like to sail in a dirigible balloon? While the wind was carrying me back to the Eiffel Tower I realised that I might be killed; but I did not feel fear. I was in no personal inconvenience. I knew my resources. I was excessively occupied. I have felt fear while in the air, yes, miserable fear joined to pain; but never in a dirigible balloon."

Even this did not daunt him. That very night he ordered a new air-ship, Santos-Dumont VI., and it was ready in twenty-two days. The new balloon had the shape of an elongated ellipsoid, 32 metres (105 feet) on its great axis, and 6 metres (20 feet) on its short axis, terminated fore and aft by cones. Its capacity was 605 cubic metres (21,362 cubic feet), giving it a lifting power of 620 kilos (1,362 pounds). Of this, 1,100 pounds were represented by keel, machinery, and his own weight, leaving a net lifting-power of 120 kilos (261 pounds).

On October 19, 1901, he made another attempt to round the Eiffel Tower, and was at last successful in winning the $20,000 prize. Following this great feat, Santos-Dumont continued his experiments at Monte Carlo, where he was wrecked over the Mediterranean Sea and escaped only by presence of mind, and he is still continuing his work.

The future of the dirigible balloon is open to debate. Santos-Dumont himself does not think there is much likelihood that it will ever have much commercial use. A balloon to carry many passengers would have to be so enormous that it could not support the machinery necessary to propel it, especially against a strong wind. But he does believe that the steerable balloon will have great importance in war time. He says:

"I have often been asked what present utility is to be expected of the dirigible balloon when it becomes thoroughly practicable. I have never pretended that its commercial possibilities could go far. The question of the air-ship in war, however, is otherwise. Mr. Hiram Maxim has declared that a flying machine in South Africa would have been worth four times its weight in gold. Henri Rochefort has said: 'The day when it is established that a man can direct an air-ship in a given direction and cause it to manœuvre as he wills ... there will remain little for the nations to do but to lay down their arms.'"

Air-Ship Pointing almost Vertically Upward.

Falling to the Sea.

Just Before the Air-Ship Lost all its Gas.

Losing its Gas and Sinking.

The Balloon Falling to the Waves.

Boats Around the Ruined Air-Ship.

But such experiments as Santos-Dumont's, whether they result immediately in producing an air-ship of practical utility in commerce or not, have great value for the facts which they are establishing as to the possibility of balloons, of motors, of light construction, of air currents, and moreover they add to the world's sum total of experiences a fine, clean sport in which men of daring and scientific knowledge show what men can do.

Manœuvering Above the Bay at Monte Carlo.

CHAPTER III
THE EARTHQUAKE MEASURER
Professor John Milne's Seismograph

Of all strange inventions, the earthquake recorder is certainly one of the most remarkable and interesting. A terrible earthquake shakes down cities in Japan, and sixteen minutes later the professor of earthquakes, in his quiet little observatory in England, measures its extent—almost, indeed, takes a picture of it. Actual waves, not unlike the waves of the sea blown up by a hurricane, have travelled through or around half the earth in this brief time; vast mountain ranges, cities, plains, and oceans have been heaved to their crests and then allowed to sink back again into their former positions. And some of these earthquake waves which sweep over the solid earth are three feet high, so that the whole of New York, perhaps, rises bodily to that height and then slides over the crest like a skiff on an ocean swell.

Professor John Milne.

From a photograph by S. Suzuki, Kudanzaka, Tokio.

At first glance this seems almost too strange and wonderful to believe, and yet this is only the beginning of the wonders which the earthquake camera—or the seismograph (earthquake writer, as the scientists call it)—has been disclosing.

Professor Milne's Sensitive Pendulum, or Seismograph, as it Appears Enclosed in its Protecting Box.

The Sensitive Pendulum, or Seismograph, as it Appears with the Protecting Box Removed.

The earthquake professor who has worked such scientific magic is John Milne. He lives in a quaint old house in the little Isle of Wight, not far from Osborne Castle, where Queen Victoria made her home part of the year. Not long ago he was a resident of Japan and professor of seismology (the science of earthquakes) at the University of Tokio, where he made his first discoveries about earthquakes, and invented marvellously delicate machines for measuring and photographing them thousands of miles away. Professor Milne is an Englishman by birth, but, like many another of his countrymen, he has visited some of the strangest nooks and corners of the earth. He has looked for coal in Newfoundland; he has crossed the rugged hills of Iceland; he has been up and down the length of the United States; he has hunted wild pigs in Borneo; and he has been in India and China and a hundred other out-of-the-way places, to say nothing of measuring earthquakes in Japan. Professor Milne laid the foundation of his unusual career in a thorough education at King's College, London, and at the School of Mines. By fortunate chance, soon after his graduation, he met Cyrus Field, the famous American, to whom the world owes the beginnings of its present ocean cable system. He was then just twenty-one, young and raw, but plucky. He thought he was prepared for anything the world might bring him; but when Field asked him one Friday if he could sail for Newfoundland the next Tuesday, he was so taken with astonishment that he hesitated, whereupon Field leaned forward and looked at him in a way that Milne has never forgotten.

"My young friend, I suppose you have read that the world was made in six days. Now, do you mean to tell me that, if this whole world was made in six days, you can't get together the few things you need in four?"

Gifu, Japan, after the Earthquake of 1891.

This and the pictures following on pages [89], [101], [111], are from Japanese photographs reproduced in "The Great Earthquake in Japan, 1891," by John Milne and W. K. Burton.

And Milne sailed the next Tuesday to begin his lifework among the rough hills of Newfoundland. Then came an offer from the Japanese Government, and he went to the land of earthquakes, little dreaming that he would one day be the greatest authority in the world on the subject of seismic disturbances. His first experiments—and they were made as a pastime rather than a serious undertaking—were curiously simple. He set up rows of pins in a certain way, so that in falling they would give some indication as to the wave movements in the earth. He also made pendulums made of strings with weights tied at the end, and from his discoveries made with these elementary instruments, he planned earthquake-proof houses, and showed the engineers of Japan how to build bridges which would not fall down when they were shaken. So highly was his work regarded that the Japanese made him an earthquake professor at Tokio and supplied him with the means for making more extended experiments. And presently we find him producing artificial earthquakes by the score. He buried dynamite deep in the ground and exploded it by means of an electric button. The miniature earthquake thus produced was carefully measured with curious instruments of Professor Milne's invention. At first one earthquake was enough at any one time, but as the experiments continued, Professor Milne sometimes had five or six earthquakes all quaking together; and once so interested did he become that he forgot all about the destructive nature of earthquakes, and ventured too near. A ton or more of earth came crashing down around him, half burying him and smashing his instruments flat. All this made the Japanese rub their eyes with astonishment, and by and by the Emperor heard of it. Of course he was deeply interested in earthquakes, because there was no telling when one might come along and shake down his palace over his head. So he sent for Professor Milne, and, after assuring himself that these experimental earthquakes really had no serious intentions, he commanded that one be produced on the spot. So Professor Milne laid out a number of toy towns and villages and hills in the palace yard with a tremendous toy earthquake underneath. The Emperor and his gayly dressed followers stood well off to one side, and when Professor Milne gave the word the Emperor solemnly pressed a button, and watched with the greatest delight the curious way in which the toy cities were quaked to earth. And after that, this surprising Englishman, who could make earthquakes as easily as a Japanese makes a lacquered basket, was held in high esteem in Japan, and for more than twenty years he studied earthquakes and invented machines for recording them. Then he returned to his home in England, where he is at work establishing earthquake stations in various parts of the world, by means of which he expects to reduce earthquake measurement to an exact science, an accomplishment which will have the greatest practical value to the commercial interests of the world, as I shall soon explain.

The Work of the Great Earthquake of 1891 in Neo Valley, Japan.

But first for a glimpse at the curious earthquake measurer itself. To begin with, there are two kinds of instruments—one to measure near-by disturbances, and the second to measure waves which come from great distances. The former instrument was used by Professor Milne in Japan, where earthquakes are frequent; the latter is used in England. The technical name for the machine which measures distant disturbances is the horizontal pendulum seismograph, and, like most wonderful inventions, it is exceedingly simple in principle, yet doing its work with marvellous delicacy and accuracy.

In brief, the central feature of the seismograph is a very finely poised pendulum, which is jarred by the slightest disturbance of the earth, the end of it being so arranged that a photograph is taken of every quiver. Set a pendulum clock on the dining-table, jar the table, and the pendulum will swing, indicating exactly with what force you have disturbed the table. In exactly the same way the delicate pendulum of the earthquake measurer indicates the shaking of the earth.

Diagram Showing Vertical and Horizontal Sections of the More Sensitive of Professor Milne's Two Pendulums, or Seismographs.

The accompanying diagram gives a very clear idea of the arrangement of the apparatus. The "boom" is the pendulum. It is customary to think of a pendulum as hanging down like that of a clock, but this is a horizontal pendulum. Professor Milne has built a very solid masonry column, reaching deep into the earth, and so firmly placed that nothing but a tremor of the hard earth itself will disturb it. Upon this is perched a firm metal stand, from the top of which the boom or pendulum, about thirty inches long, is swung by means of a "tie" or stay. The end of the boom rests against a fine, sharp pivot of steel (as shown in the little diagram to the right), so that it will swing back and forth without the least friction. The sensitive end of the pendulum, where all the quakings and quiverings are shown most distinctly, rests exactly over a narrow roll of photographic film, which is constantly turned by clockwork, and above this, on an outside stand, there is a little lamp which is kept burning night and day, year in and year out. The light from this lamp is reflected downward by means of a mirror through a little slit in the metal case which covers the entire apparatus. Of course this light affects the sensitive film, and takes a continuous photograph of the end of the boom. If the boom remains perfectly still, the picture will be merely a straight line, as shown at the extreme right and left ends of the earthquake picture on this page. But if an earthquake wave comes along and sets the boom to quivering, the picture becomes at once blurred and full of little loops and indentations, slight at first, but becoming more violent as the greater waves arrive, and then gradually subsiding. In the picture of the Borneo earthquake of September 20, 1897, taken by Professor Milne in his English laboratory, it will be seen that the quakings were so severe at the height of the disturbance that nothing is left in the photograph but a blur. On the edge of the picture can be seen the markings of the hours, 7.30, 8.30, and 9.30. Usually this time is marked automatically on the film by means of the long hand of a watch which crosses the slit beneath the mirror (as shown in the lower diagram with figure 3). The Borneo earthquake waves lasted in England, as will be seen, two hours fifty-six minutes and fifteen seconds, with about forty minutes of what are known as preliminary tremors. Professor Milne removes the film from his seismograph once a week—a strip about twenty-six feet long—develops it, and studies the photographs for earthquake signs.

Seismogram of a Borneo Earthquake that Occurred September 20, 1897.

Besides this very sensitive photographic seismograph Professor Milne has a simpler machine, not covered up and without lamp or mirror. In this instrument a fine silver needle at the end of the boom makes a steady mark on a band of smoked paper, which is kept turning under it by means of clockwork. A glance at this smoked-paper record will tell instantly at any time of day or night whether the earth is behaving itself. If the white line on the dark paper shows disturbances, Professor Milne at once examines his more sensitive photographic record for the details.

It is difficult to realise how very sensitive these earthquake pendulums really are. They will indicate the very minutest changes in the earth's level—as slight as one inch in ten miles. A pair of these pendulums placed on two buildings at opposite sides of a city street would show that the buildings literally lean toward each other during the heavy traffic period of the day, dragged over from their level by the load of vehicles and people pressing down upon the pavement between them. The earth is so elastic that a comparatively small impetus will set it vibrating. Why, even two hills tip together when there is a heavy load of moisture in a valley between them. And then when the moisture evaporates in a hot sun they tip away from each other. These pendulums show that.

Nor are these the most extraordinary things which the pendulums will do. G. K. Gilbert, of the United States Geological Survey, argues that the whole region of the great lakes is being slowly tipped to the southwest, so that some day Chicago will sink and the water outlet of the great fresh-water seas will be up the Chicago River toward the Mississippi, instead of down the St. Lawrence. Of course this movement is as slow as time itself—thousands of years must elapse before it is hardly appreciable; and yet Professor Milne's instruments will show the changing balance—a marvel that is almost beyond belief. Strangely enough, sensitive as this special instrument is to distant disturbances, it does not swerve nor quiver for near-by shocks. Thus, the blasting of powder, the heavy rumbling of wagons, the firing of artillery has little or no effect in producing a movement of the boom. The vibrations are too short; it requires the long, heavy swells of the earth to make a record.

Professor Milne tells some odd stories of his early experiences with the earthquake measurer. At one time his films showed evidences of the most horrible earthquakes, and he was afraid for the moment that all Japan had been shaken to pieces and possibly engulfed by the sea. But investigation showed that a little grey spider had been up to pranks in the box. The spider wasn't particularly interested in earthquakes, but he took the greatest pleasure in the swinging of the boom, and soon began to join in the game himself. He would catch the end of the boom with his feelers and tug it over to one side as far as ever he could. Then he would anchor himself there and hold on like grim death until the boom slipped away. Then he would run after it, and tug it over to the other side, and hold it there until his strength failed again. And so he would keep on for an hour or two until quite exhausted, enjoying the fun immensely, and never dreaming that he was manufacturing wonderful seismograms to upset the scientific world, since they seemed to indicate shocking earthquake disasters in all directions.

Mr. Cleveland Moffett, to whom I am indebted for much of the information contained in this chapter, tells how the reporters for the London papers rush off to see Professor Milne every time there is news of a great earthquake, and how he usually corrects their information. In June, 1896, for instance, the little observatory was fairly besieged with these searchers for news.

"This earthquake happened on the 17th," said they, "and the whole eastern coast of Japan was overwhelmed with tidal waves, and 30,000 lives were lost."

"That last is probable," answered Professor Milne, "but the earthquake happened on the 15th, not the 17th;" and then he gave them the exact hour and minute when the shocks began and ended.

"But our cables put it on the 17th."

"Your cables are mistaken."

And, sure enough, later despatches came with information that the destructive earthquake had occurred on the 15th, within half a minute of the time Professor Milne had specified. There had been some error of transmission in the earlier newspaper despatches.

Again, a few months later, the newspapers published cablegrams to the effect that there had been a severe earthquake at Kobe, with great injury to life and property.

"That is not true," said Professor Milne. "There may have been a slight earthquake at Kobe, but nothing that need cause alarm."

And the mail reports a few weeks later confirmed his reassuring statement, and showed that the previous sensational despatches had been grossly exaggerated.

Professor Milne is also the man to whose words cable companies lend anxious ear, for what he says often means thousands of dollars to them. Early in January, 1898, it was officially reported that two West Indian cables had broken on December 31, 1897.

"That is very unlikely," said Professor Milne; "but I have a seismogram showing that these cables may have broken at 11.30 A.M. on December 29, 1897." And then he located the break at so many miles off the coast of Haiti.

This sort of thing, which is constantly happening, would look very much like magic if Professor Milne had kept his secrets to himself; but he has given them freely to all the world.

Effect of the Great Earthquake of 1891 on the Nagara Gawa Railway Bridge, Japan.

Professor Milne has learned from his experiments that the solid earth is full of movements, and tremors, and even tides, like the sea. We do not notice them, because they are so slow and because the crests of the waves are so far apart. Professor Milne likes to tell, fancifully, how the earth "breathes." He has found that nearly all earthquake waves, whether the disturbance is in Borneo or South America, reach his laboratory in sixteen minutes, and he thinks that the waves come through the earth instead of around it. If they came around, he says, there would be two records—one from waves coming the short way and one from waves coming the long way round. But there is never more than a single record, so he concludes that the waves quiver straight through the solid earth itself, and he believes that this fact will lead to some important discoveries about the centre of our globe. Professor Milne was once asked how, if earthquake waves from every part of the earth reached his observatory in the same number of minutes, he could tell where the earthquake really was.

"I may say, in a general way," he replied, "that we know them by their signatures, just as you know the handwriting of your friends; that is, an earthquake wave which has travelled 3,000 miles makes a different record in the instruments from one that has travelled 5,000 miles; and that, again, a different record from one that has travelled 7,000 miles, and so on. Each one writes its name in its own way. It's a fine thing, isn't it, to have the earth's crust harnessed up so that it is forced to mark down for us on paper a diagram of its own movements?"

He took pencil and paper again, and dashed off an earthquake wave like this:

"There you have the signature of an earthquake wave which has travelled only a short distance, say 2,000 miles; but here is the signature of the very same wave after travelling, say, 6,000 miles:"

"You see the difference at a glance; the second seismogram (that is what we call these records) is very much more stretched out than the first, and a seismogram taken at 8,000 miles from the start would be more stretched out still. This is because the waves of transmission grow longer and longer, and slower and slower, the farther they spread from the source of disturbance. In both figures the point A, where the straight line begins to waver, marks the beginning of the earthquake; the rippling line AB shows the preliminary tremors which always precede the heavy shocks, marked C; and D shows the dying away of the earthquake in tremors similar to AB.

"Now, it is chiefly in the preliminary tremors that the various earthquakes reveal their identity. The more slowly the waves come, the longer it takes to record them, and the more stretched out they become in the seismograms. And by carefully noting these differences, especially those in time, we get our information. Suppose we have an earthquake in Japan. If you were there in person you would feel the preliminary tremors very fast, five or ten in a second, and their whole duration before the heavy shocks would not exceed ten or twenty seconds. But these preliminary tremors, transmitted to England, would keep the pendulums swinging from thirty to thirty-two minutes before the heavy shocks, and each vibration would occupy five seconds.

"There would be similar differences in the duration of the heavy vibrations; in Japan they would come at the rate of about one a second: here, at the rate of about one in twenty or forty seconds. It is the time, then, occupied by the preliminary tremors that tells us the distance of the earthquake. Earthquakes in Borneo, for instance, give preliminary tremors occupying about forty-one minutes, in Japan about half an hour, in the earthquake region east of Newfoundland about eight minutes, in the disturbed region of the West Indies about nineteen or twenty minutes, and so on. Thus the earthquake is located with absolute precision."

Most earthquakes occur in the deep bed of the ocean, in the vast valleys between ocean mountains, and the dangerous localities are now almost as well known as the principal mountain ranges of North America. There is one of these valleys, or ocean holes, off the west coast of South America from Ecuador down; there is one in the mid-Atlantic, about the equator, between twenty degrees and forty degrees west longitude: there is one at the Grecian end of the Mediterranean; one in the Bay of Bengal, and one bordering the Alps; there is the famous "Tuscarora Deep," from the Philippine Islands down to Java; and there is the North Atlantic region, about 300 miles east of Newfoundland. In the "Tuscarora Deep" the slope increases 1,000 fathoms in twenty-five miles, until it reaches a depth of 4,000 fathoms.

Pieces of a Submarine Cable Picked Up in the Gulf of Mexico in 1888.

The kinks are caused by seismic disturbances, and they show how much distortion a cable can suffer and still remain in good electrical condition, as this was found to be.

And this brings us to the consideration of one of the greatest practical advantages of the seismograph—in the exact location of cable breaks. Indeed, a large proportion of these breaks are the result of earthquakes. In a recent report Professor Milne says that there are now about twenty-seven breaks a year for 10,000 miles of cable in active use. Most of these are very costly, fifteen breaks in the Atlantic cable between 1884 and 1894 having cost the companies $3,000,000, to say nothing of loss of time. And twice it has happened in Australia (in 1880 and 1888) that the whole island has been thrown into excitement and alarm, the reserves being called out, and other measures taken, because the sudden breaking of cable connections with the outside world has led to the belief that military operations against the country were preparing by some foreign power. A Milne pendulum at Sydney or Adelaide would have made it plain in a moment that the whole trouble was due to a submarine earthquake occurring at such a time and such a place. As it was, Australia had to wait in a fever of suspense (in one case there was a delay of nineteen days) until steamers arriving brought assurances that neither Russia nor any other possibly unfriendly power had begun hostilities by tearing up the cables.

There have been submarine earthquakes in the Tuscarora, like that of June 15, 1896, that have shaken the earth from pole to pole; and more than once different cables from Java have been broken simultaneously, as in 1890, when the three cables to Australia snapped in a moment. And the great majority of breaks in the North Atlantic cables have occurred in the Newfoundland hollow, where there are two slopes, one dropping from 708 to 2,400 fathoms in a distance of sixty miles, and the other from 275 to 1,946 fathoms within thirty miles. On October 4, 1884, three cables, lying about ten miles apart, broke simultaneously at the spot. The significance of such breaks is greater when the fact is borne in mind that cables frequently lie uninjured for many years on the great level plains of the ocean bed, where seismic disturbances are infrequent.

The two chief causes of submarine earthquakes are landslides, where enormous masses of earth plunge from a higher to a lower level, and in so doing crush down upon the cable, and "faults," that is, subsidences of great areas, which occur on land as well as at the bottom of the sea, and which in the latter case may drag down imbedded cables with them.

It is in establishing the place and times of these breaks that Professor Milne's instruments have their greatest practical value; scientifically no one can yet calculate their value.

Record Made on a Stationary Surface by the Vibrations of the Japanese Earthquake of July 19, 1891.

Showing the complicated character of the motion (common to most earthquakes), and also the course of a point at the centre of disturbance.

In addition to the first instrument set up by Professor Milne in Tokio in 1883, which is still recording earthquakes, there are now in operation about twenty other seismographs in various parts of the world, so that earthquake information is becoming very accurate and complete, and there is even an attempt being made to predict earthquakes just as the weather bureau predicts storms. In any event Professor Milne's invention must within a few years add greatly to our knowledge of the wonders of the planet on which we live.

CHAPTER IV
ELECTRICAL FURNACES
How the Hottest Heat is Produced—Making Diamonds

No feats of discovery, not even the search for the North Pole or Stanley's expeditions in the heart of Africa, present more points of fascinating interest than the attempts now being made by scientists to explore the extreme limits of temperature. We live in a very narrow zone in what may be called the great world of heat. The cut on the opposite page represents an imaginary thermometer showing a few of the important temperature points between the depths of the coldest cold and the heights of the hottest heat—a stretch of some 10,461 degrees. We exist in a narrow space, as you will see, varying from 100° or a little more above the zero point to a possible 50° below; that is, we can withstand these narrow extremes of temperature. If some terrible world catastrophe should raise the temperature of our summers or lower that of our winters by a very few degrees, human life would perish off the earth.

But though we live in such narrow limits, science has found ways of exploring the great heights of heat above us and of reaching and measuring the depths of cold below us, with the result of making many important and interesting discoveries.

I have written in the former "Boys' Book of Inventions" of that wonderful product of science, liquid air—air submitted to such a degree of cold that it ceases to be a gas and becomes a liquid. This change occurs at a temperature 312° below zero. Professor John Dewar, of England, who has made some of the most interesting of discoveries in the region of great cold, not only reached a temperature low enough to produce liquid air, but he succeeded in going on down until he could freeze this marvellous liquid into a solid—a sort of air ice. Not content even with this astonishing degree of cold, Professor Dewar continued his experiments until he could reduce hydrogen—that very light gas—to a liquid, at 440° below zero, and then, strange as it may seem, he also froze liquid hydrogen into a solid. From his experiments he finally concluded that the "absolute zero"—that is, the place where there is no heat—was at a point 461° below zero. And he has been able to produce a temperature, artificially, within a very few degrees of this utmost limit of cold.

Think what this absolute zero means. Heat, we know, like electricity and light, is a vibratory or wave motion in the ether. The greater the heat, the faster the vibrations. We think of all the substances around us as solids, liquids, and gases, but these are only comparative terms. A change of temperature changes the solid into the liquid, or the gas into the solid. Take water, for instance. In the ordinary temperature of summer it is a liquid, in winter it is a hard crystalline substance called ice; apply the heat of a stove and it becomes steam, a gas. So with all other substances. Air to us is an invisible gas, but if the earth should suddenly drop in temperature to 312° below zero all the air would fall in liquid drops like rain and fill the valleys of the earth with lakes and oceans. Still a little colder and these lakes and oceans would freeze into solids. Similarly, steel seems to us a very hard and solid substance, but apply enough heat and it boils like water, and finally, if the heat be increased, it becomes a gas.

Imagine, if you can, a condition in which all substances are solids; where the vibrations known as heat have been stilled to silence; where nothing lives or moves; where, indeed, there is an awful nothingness; and you can form an idea of the region of the coldest cold—in other words, the region where heat does not exist. Our frozen moon gives something of an idea of this condition, though probably, cold and barren as it is, the moon is still a good many degrees in temperature above the absolute zero.

Some of the methods of exploring these depths of cold are treated in the chapter on liquid air already referred to. Our interest here centres in the other extreme of temperature, where the heat vibrations are inconceivably rapid; where nearly all substances known to man become liquids and gases; where, in short, if the experimenter could go high enough, he could reach the awful degree of heat of the burning sun itself, estimated at over 10,000 degrees. It is in the work of exploring these regions of great heat that such men as Moissan, Siemens, Faure, and others have made such remarkable discoveries, reaching temperatures as high as 7,000, or over twice the heat of boiling steel. Their accomplishments seem the more wonderful when we consider that a temperature of this degree burns up or vaporises every known substance. How, then, could these men have made a furnace in which to produce this heat? Iron in such a heat would burn like paper, and so would brick and mortar. It seems inconceivable that even science should be able to produce a degree of heat capable of consuming the tools and everything else with which it is produced.

The heat vibrations at 7,000° are so intense that nickel and platinum, the most refractory, the most unmeltable of metals, burn like so much bee's-wax; the best fire-brick used in lining furnaces is consumed by it like lumps of rosin, leaving no trace behind. It works, in short, the most marvellous, the most incredible transformations in the substances of the earth.

Indeed, we have to remember that the earth itself was created in a condition of great heat—first a swirling, burning gas, something like the sun of to-day, gradually cooling, contracting, rounding, until we have our beautiful world, with its perfect balance of gases, liquids, solids, its splendid life. A dying volcano here and there gives faint evidence of the heat which once prevailed over all the earth.

It was in the time of great heat that the most beautiful and wonderful things in the world were wrought. It was fierce heat that made the diamond, the sapphire, and the ruby; it fashioned all of the most beautiful forms of crystals and spars; and it ran the gold and silver of the earth in veins, and tossed up mountains, and made hollows for the seas. It is, in short, the temperature at which worlds were born.

More wonderful, if possible, than the miracles wrought by such heat is the fact that men can now produce it artificially; and not only produce, but confine and direct it, and make it do their daily service. One asks himself, indeed, if this can really be; and it was under the impulse of some such incredulity that I lately made a visit to Niagara Falls, where the hottest furnaces in the world are operated. Here clay is melted in vast quantities to form aluminium, a metal as precious a few years ago as gold. Here lime and carbon, the most infusible of all the elements, are joined by intense heat in the curious new compound, calcium carbide, a bit of which dropped in water decomposes almost explosively, producing the new illuminating gas, acetylene. Here, also, pure phosphorus and the phosphates are made in large quantities; and here is made carborundum—gem-crystals as hard as the diamond and as beautiful as the ruby.

An extensive plant has also been built to produce the heat necessary to make graphite such as is used in your lead-pencils, and for lubricants, stove-blacking, and so on. Graphite has been mined from the earth for thousands of years; it is pure carbon, first cousin to the diamond. Ten years ago the possibility of its manufacture would have been scouted as ridiculous; and yet in these wonderful furnaces, which repeat so nearly the processes of creation, graphite is as easily made as soap. The marvel-workers at Niagara Falls have not yet been able to make diamonds—in quantities. The distinguished French chemist Moissan has produced them in his laboratory furnaces—small ones, it is true, but diamonds; and one day they may be shipped in peck boxes from the great furnaces at Niagara Falls. This is no mere dream; the commercial manufacture of diamonds has already had the serious consideration of level-headed, far-seeing business men, and it may be accounted a distinct probability. What revolution the achievement of it would work in the diamond trade as now constituted and conducted no one can say.

These marvellous new things in science and invention have been made possible by the chaining of Niagara to the wheels of industry. The power of the falling water is transformed into electricity. Electricity and heat are both vibratory motions of the ether; science has found that the vibrations known as electricity can be changed into the vibrations known as heat. Accordingly, a thousand horse-power from the mighty river is conveyed as electricity over a copper wire, changed into heat and light between the tips of carbon electrodes, and there works its wonders. In principle the electrical furnace is identical with the electric light. It is scarcely twenty years since the first electrical furnaces of real practical utility were constructed; but if the electrical furnaces to-day in operation at Niagara Falls alone were combined into one, they would, as one scientist speculates, make a glow so bright that it could be seen distinctly from the moon—a hint for the astronomers who are seeking methods for communicating with the inhabitants of Mars. One furnace has been built in which an amount of heat energy equivalent to 700 horse-power is produced in an arc cavity not larger than an ordinary water tumbler.

On reaching Niagara Falls, I called on Mr. E. G. Acheson, whose name stands with that of Moissan as a pioneer in the investigation of high temperatures. Mr. Acheson is still a young man—not more than forty-five at most—and clean-cut, clear-eyed, and genial, with something of the studious air of a college professor. He is pre-eminently a self-made man. At twenty-four he found a place in Edison's laboratory—"Edison's college of inventions," he calls it—and, at twenty-five, he was one of the seven pioneers in electricity who (in 1881-82) introduced the incandescent lamp in Europe. He installed the first electric-light plants in the cities of Milan, Genoa, Venice, and Amsterdam, and during this time was one of Edison's representatives in Paris.

Mr. E. G. Acheson, One of the Pioneers in the Investigation of High Temperatures.

"I think the possibility of manufacturing genuine diamonds," he said to me, "has dazzled more than one young experimenter. My first efforts in this direction were made in 1880. It was before we had command of the tremendous electric energy now furnished by the modern dynamo, and when the highest heat attainable for practical purposes was obtained by the oxy-hydrogen flame. Even this was at the service of only a few experimenters, and certainly not at mine. My first experiments were made in what I might term the 'wet way'; that is, by the process of chemical decomposition by means of an electric current. Very interesting results were obtained, which even now give promise of value; but the diamond did not materialise.

"I did not take up the subject again until the dynamo had attained high perfection and I was able to procure currents of great power. Calling in the aid of the 6,500 degrees Fahrenheit or more of temperature produced by these electric currents, I once more set myself to the solution of the problem. I now had, however, two distinct objects in view: first, the making of a diamond; and, second, the production of a hard substance for abrasive purposes. My experiments in 1880 had resulted in producing a substance of extreme hardness, hard enough, indeed, to scratch the sapphire—the next hardest thing to the diamond—and I saw that such a material, cheaply made, would have great value.

"My first experiment in this new series was of a kind that would have been denounced as absurd by any of the old-school book-chemists, and had I had a similar training, the probability is that I should not have made such an investigation. But 'fools rush in where angels fear to tread,' and the experiment was made."

This experiment by Mr. Acheson, extremely simple in execution, was the first act in rolling the stone from the entrance to a veritable Aladdin's cave, into which a multitude of experimenters have passed in their search for nature's secrets; for, while the use of the electrical furnace in the reduction of metals—in the breaking down of nature's compounds—was not new, its use for synthetic chemistry—for the putting together, the building up, the formation of compounds—was entirely new. It has enabled the chemist not only to reproduce the compounds of nature, but to go further and produce valuable compounds that are wholly new and were heretofore unknown to man. Mr. Acheson conjectured that carbon, if made to combine with clay, would produce an extremely hard substance; and that, having been combined with the clay, if it should in the cooling separate again from the clay, it would issue out of the operation as diamond. He therefore mixed a little clay and coke dust together, placed them in a crucible, inserted the ends of two electric-light carbons into the mixture, and connected the carbons with a dynamo. The fierce heat generated at the points of the carbons fused the clay, and caused portions of the carbon to dissolve. After cooling, a careful examination was made of the mass, and a few small purple crystals were found. They sparkled with something of the brightness of diamonds, and were so hard that they scratched glass. Mr. Acheson decided at once that they could not be diamonds; but he thought they might be rubies or sapphires. A little later, though, when he had made similar crystals of a larger size, he found that they were harder than rubies, even scratching the diamond itself. He showed them to a number of expert jewellers, chemists, and geologists. They had so much the appearance of natural gems that many experts to whom they were submitted without explanation decided that they must certainly be of natural production. Even so eminent an authority as Geikie, the Scotch geologist, on being told, after he had examined them, that the crystals were manufactured in America, responded testily: "These Americans! What won't they claim next? Why, man, those crystals have been in the earth a million years."

Mr. Acheson decided at first that his crystals were a combination of carbon and aluminium, and gave them the name carborundum. He at once set to work to manufacture them in large quantities for use in making abrasive wheels, whetstones, and sandpaper, and for other purposes for which emery and corundum were formerly used. He soon found by chemical analysis, however, that carborundum was not composed of carbon and aluminium, but of carbon and silica, or sand, and that he had, in fact, created a new substance; so far as human knowledge now extends, no such combination occurs anywhere in nature. And it was made possible only by the electrical furnace, with its power of producing heat of untold intensity.

The Furnace-Room, where Carborundum is Made.

"A great, dingy brick building, open at the sides like a shed."

In order to get a clear understanding of the actual workings of the electrical furnace, I visited the plant where Mr. Acheson makes carborundum. The furnace-room is a great, dingy brick building, open at the sides like a shed. It is located only a few hundred yards from the banks of the Niagara River and well within the sound of the great falls. Just below it, and nearer the city, stands the handsome building of the Power Company, in which the mightiest dynamos in the world whir ceaselessly, day and night, while the waters of Niagara churn in the water-wheel pits below. Heavy copper wires carrying a current of 2,200 volts lead from the power-house to Mr. Acheson's furnaces, where the electrical energy is transformed into heat.

There are ten furnaces in all, built loosely of fire-brick, and fitted at each end with electrical connections. And strange they look to one who is familiar with the ordinary fuel furnace, for they have no chimneys, no doors, no drafts, no ash-pits, no blinding glow of heat and light. The room in which they stand is comfortably cool. Each time a furnace is charged it is built up anew; for the heat produced is so fierce that it frequently melts the bricks together, and new ones must be supplied. There were furnaces in many stages of development. One had been in full blast for nearly thirty hours, and a weird sight it was. The top gave one the instant impression of the seamy side of a volcano. The heaped coke was cracked in every direction, and from out of the crevices and depressions and from between the joints of the loosely built brick walls gushed flames of pale green and blue, rising upward, and burning now high, now low, but without noise beyond a certain low humming. Within the furnace—which was oblong in shape, about the height of a man, and sixteen feet long by six wide—there was a channel, or core, of white-hot carbon in a nearly vaporised state. It represented graphically in its seething activity what the burning surface of the sun might be—and it was almost as hot. Yet the heat was scarcely manifest a dozen feet from the furnace, and but for the blue flames rising from the cracks in the envelope, or wall, one might have laid his hand almost anywhere on the bricks without danger of burning it.

Taking Off a Crust of the Furnace at Night.

The light is so intense that you cannot look at it without hurting the eyes.

In the best modern blast-furnaces, in which the coal is supplied with special artificial draft to make it burn the more fiercely, the heat may reach 3,000 degrees Fahrenheit. This is less than half of that produced in the electrical furnace. In porcelain kilns, the potters, after hours of firing, have been able to produce a cumulative temperature of as much as 3,300 degrees Fahrenheit; and this, with the oxy-hydrogen flame (in which hydrogen gas is spurred to greater heat by an excess of oxygen), is the very extreme of heat obtainable by any artificial means except by the electrical furnace. Thus the electrical furnace has fully doubled the practical possibilities in the artificial production of heat.

Mr. Fitzgerald, the chemist of the Acheson Company, pointed out to me a curious glassy cavity in one of the half-dismantled furnaces. "Here the heat was only a fraction of that in the core," he said. But still the fire-brick—and they were the most refractory produced in this country—had been melted down like butter. The floors under the furnace were all made of fire-brick, and yet the brick had run together until they were one solid mass of glassy stone. "We once tried putting a fire-brick in the centre of the core," said Mr. Fitzgerald, "just to test the heat. Later, when we came to open the furnace, we couldn't find a vestige of it. The fire had totally consumed it, actually driving it all off in vapour."

Indeed, so hot is the core that there is really no accurate means of measuring its temperature, although science has been enabled by various curious devices to form a fairly correct estimate. The furnace has a provoking way of burning up all of the thermometers and heat-measuring devices which are applied to it. A number of years ago a clever German, named Segar, invented a series of little cones composed of various infusible earths like clay and feldspar. He so fashioned them that one in the series would melt at 1,620 degrees Fahrenheit, another at 1,800 degrees, and so on up. If the cones are placed in a pottery kiln, the potter can tell just what degree of temperature he has reached by the melting of the cones one after another. But in Mr. Acheson's electrical furnaces all the cones would burn up and disappear in two minutes. The method employed for coming at the heat of the electrical furnace, in some measure, is this: a thin filament of platinum is heated red hot—1,800 degrees Fahrenheit—by a certain current of electricity. A delicate thermometer is set three feet away, and the reading is taken. Then, by a stronger current, the filament is made white hot—3,400 degrees Fahrenheit—and the thermometer moved away until it reads the same as it read before. Two points in a distance-scale are thus obtained as a basis of calculation. The thermometer is then tried by an electrical furnace. To be kept at the same marking it must be placed much farther away than in either of the other instances. A simple computation of the comparative distances with relation to the two well-ascertained temperatures gives approximately, at least, the temperature of the electrical furnace. Some other methods are also employed. None is regarded as perfectly exact; but they are near enough to have yielded some very interesting and valuable statistics regarding the power of various temperatures. For instance, it has been found that aluminium becomes a limpid liquid at from 4,050 to 4,320 degrees Fahrenheit, and that lime melts at from 4,940 to 5,400 degrees, and magnesia at 4,680 degrees.

There are two kinds of electrical furnaces, as there are two kinds of electric lights—arc and incandescent. Moissan has used the arc furnace in all of his experiments, but Mr. Acheson's furnaces follow rather the principle of the incandescent lamp. "The incandescent light," said Mr. Fitzgerald, "is produced by the resistance of a platinum wire or a carbon filament to the passage of a current of electricity. Both light and heat are given off. In our furnace, the heat is produced by the resistance of a solid cylinder or core of pulverised coke to the passage of a strong current of electricity. When the core becomes white hot it causes the materials surrounding it to unite chemically, producing the carborundum crystals."

The materials used are of the commonest—pure white sand, coke, sawdust, and salt. The sand and coke are mixed in the proportions of sixty to forty, the sawdust is added to keep the mixture loose and open, and the salt to assist the chemical combination of the ingredients. The furnace is half filled with this mixture, and then the core of coke, twenty-one inches in diameter, is carefully moulded in place. This core is sixteen feet long, reaching the length of the furnace, and connecting at each end with an immense carbon terminal, consisting of no fewer than twenty-five rods of carbon, each four inches square and nearly three feet long. These terminals carry the current into the core from huge insulated copper bars connected from above. When the core is complete, more of the carborundum mixture is shovelled in and tramped down until the furnace is heaping full.

Everything is now ready for the electric current. The wires from the Niagara Falls power-plant come through an adjoining building, where one is confronted, upon entering, with this suggestive sign:

DANGER
2,200 Volts.

Tesla produces immensely higher voltages than this for laboratory experiments, but there are few more powerful currents in use in this country for practical purposes. Only about 2,000 volts are required for executing criminals under the electric method employed in New York; 400 volts will run a trolley-car. It is hardly comfortable to know that a single touch of one of the wires or switches in this room means almost certain death. Mr. Fitzgerald gave me a vivid demonstration of the terrific destructive force of the Niagara Falls current. He showed me how the circuit was broken. For ordinary currents, the breaking of a circuit simply means a twist of the wrist and the opening of a brass switch. Here, however, the current is carried into a huge iron tank full of salt water. The attendant, pulling on a rope, lifts an iron plate from the tank. The moment it leaves the water, there follow a rumbling crash like a thunder-clap, a blinding burst of flame, and thick clouds of steam and spray. The sight and sound of it make you feel delicate about interfering with a 2,200-volt current.

The Interior of a Furnace as it Appears after the Carborundum has been Taken Out.

This current is, indeed, too strong in voltage for the furnaces, and it is cut down, by means of what were until recently the largest transformers in the world, to about 100 volts, or one-fourth the pressure used on the average trolley line. It is now, however, a current of great intensity—7,500 ampères, as compared with the one-half ampère used in an incandescent lamp; and it requires eight square inches of copper and 400 square inches of carbon to carry it.

Within the furnace, when the current is turned on, a thousand horse-power of energy is continuously transformed into heat. Think of it! Is it any wonder that the temperature goes up? And this is continued for thirty-six hours steadily, until 36,000 "horse-power hours" are used up and 7,000 pounds of the crystals have been formed. Remembering that 36,000 horse-power hours, when converted into heat, will raise 72,000 gallons of water to the boiling point, or will bring 350 tons of iron up to a red heat, one can at least have a sort of idea of the heat evolved in a carborundum furnace.

When the coke core glows white, chemical action begins in the mixture around it. The top of the furnace now slowly settles, and cracks in long, irregular fissures, sending out a pungent gas which, when lighted, burns lambent blue. This gas is carbon monoxide, and during the process nearly six tons of it are thrown off and wasted. It seems, indeed, a somewhat extravagant process, for fifty-six pounds of gas are produced for every forty of carborundum.

"It is very distinctly a geological condition," said Mr. Fitzgerald; "crystals are not only formed exactly as they are in the earth, but we have our own little earthquakes and volcanoes." Not infrequently gas collects, forming a miniature mountain, with a crater at its summit, and blowing a magnificent fountain of flame, lava, and dense white vapour high into the air, and roaring all the while in a most terrifying manner. The workmen call it "blowing off."

Blowing Off.

"Not infrequently gas collects, forming a miniature mountain, with a crater at its summit, and blowing a magnificent fountain of flame, lava, and dense white vapour high into the air, and roaring all the while in a most terrifying manner."

At the end of thirty-six hours the current is cut off, and the furnace is allowed to cool, the workmen pulling down the brick as rapidly as they dare. At the centre of the furnace, surrounding the core, there remains a solid mass of carborundum as large in diameter as a hogshead. Portions of this mass are sometimes found to be composed of pure, beautifully crystalline graphite. This in itself is a surprising and significant product, and it has opened the way directly to graphite-making on a large scale. An important and interesting feature of the new graphite industry is the utilisation it has effected of a product from the coke regions of Pennsylvania which was formerly absolute waste.

To return to carborundum: when the furnace has been cooled and the walls torn away, the core of carborundum is broken open, and the beautiful purple and blue crystals are laid bare, still hot. The sand and the coke have united in a compound nearly as hard as the diamond and even more indestructible, being less inflammable and wholly indissoluble in even the strongest acids. After being taken out, the crystals are crushed to powder and combined in various forms convenient for the various uses for which it is designed.

I asked Mr. Acheson if he could make diamonds in his furnaces. "Possibly," he answered, "with certain modifications." Diamonds, as he explained, are formed by great heat and great pressure. The great heat is now easily obtained, but science has not yet learned nature's secret of great pressure. Moissan's method of making diamonds is to dissolve coke dust in molten iron, using a carbon crucible into which the electrodes are inserted. When the whole mass is fluid, the crucible and its contents are suddenly dashed into cold water or melted lead. This instantaneous cooling of the iron produces enormous pressure, so that the carbon is crystallised in the form of diamond.

But whatever it may or may not yet be able to do in the matter of diamond-making, there can be no doubt that the possibilities of the electrical furnace are beyond all present conjecture. With American inventors busy in its further development, and with electricity as cheap as the mighty power of Niagara can make it, there is no telling what new and wonderful products, now perhaps wholly unthought-of by the human race, it may become possible to manufacture, and manufacture cheaply.

CHAPTER V
HARNESSING THE SUN
The Solar Motor

It seems daring and wonderful enough, the idea of setting the sun itself to the heavy work of men, producing the power which will help to turn the wheels of this age of machinery.

At Los Angeles, Cal., I went out to see the sun at work pumping water. The solar motor, as it is called, was set up at one end of a great enclosure where ostriches are raised. I don't know which interested me more at first, the sight of these tall birds striding with dignity about their roomy pens or sitting on their big yellow eggs—just as we imagine them wild in the desert—or the huge, strange creation of man by which the sun is made to toil. I do not believe I could have guessed the purpose of this unique invention if I had not known what to expect. I might have hazarded the opinion that it was some new and monstrous searchlight: beyond that I think my imagination would have failed me. It resembled a huge inverted lamp-shade, or possibly a tremendous iron-ribbed colander, bottomless, set on its edge and supported by a steel framework. Near by there was a little wooden building which served as a shop or engine-house. A trough full of running water led away on one side, and from within came the steady chug-chug, chug-chug of machinery, apparently a pump. So this was the sun-subduer! A little closer inspection, with an audience of ostriches, very sober, looking over the fence behind me and wondering, I suppose, if I had a cracker in my pocket, I made out some other very interesting particulars in regard to this strange invention. The colander-like device was in reality, I discovered, made up of hundreds and hundreds (nearly 1,800 in all) of small mirrors, the reflecting side turned inward, set in rows on the strong steel framework which composed the body of the great colander. By looking up through the hole in the bottom of the colander I was astonished by the sight of an object of such brightness that it dazzled my eyes. It looked, indeed, like a miniature sun, or at least like a huge arc light or a white-hot column of metal. And, indeed, it was white hot, glowing, burning hot—a slim cylinder of copper set in the exact centre of the colander. At the top there was a jet of white steam like a plume, for this was the boiler of this extraordinary engine.

Side View of the Solar Motor.

"It is all very simple when you come to see it," the manager was saying to me. "Every boy has tried the experiment of flashing the sunshine into his chum's window with a mirror. Well, we simply utilise that principle. By means of these hundreds of mirrors we reflect the light and heat of the sun on a single point at the centre of what you have described as a colander. Here we have the cylinder of steel containing the water which we wish heated for steam. This cylinder is thirteen and one-half feet long and will hold one hundred gallons of water. If you could see it cold, instead of glowing with heat, you would find it jet black, for we cover it with a peculiar heat-absorbing substance made partly of lampblack, for if we left it shiny it would re-reflect some of the heat which comes from the mirrors. The cold water runs in at one end through this flexible metallic hose, and the steam goes out at the other through a similar hose to the engine in the house."

Though this colander, or "reflector," as it is called, is thirty-three and one-half feet in diameter at the outer edge and weighs over four tons, it is yet balanced perfectly on its tall standards. It is, indeed, mounted very much like a telescope, in meridian, and a common little clock in the engine-room operates it so that it always faces the sun, like a sunflower, looking east in the morning and west in the evening, gathering up the burning rays of the sun and throwing them upon the boiler at the centre. In the engine-house I found a pump at work, chug-chugging like any pump run by steam-power, and the water raised by sun-power flowing merrily away. The manager told me that he could easily get ten horse-power; that, if the sun was shining brightly, he could heat cold water in an hour to produce 150 pounds of steam.