Elmer Ellsworth Burns

“ Rumford had found that the work of a horse can produce heat, and heat, in a steam-engine, can do the work of a horse. Thus surely, though slowly, men were learning of the forces that move the world and do man's bidding.
Count Rumford, true to his adopted land, returned to London and became the founder of the Royal Institution in which Faraday and his successors have achieved such marvellous results. He believed that the poor can be helped in no better way than by giving them knowledge, so that they can better their own condition. ”

“ A machine must be invented that would do the work of the women and horses, a machine strong enough to raise coal with speed from the deepest mines. Then it happened that two great inventors, Newcomen and Watt, arose to produce the machine that was needed. When the world needs an invention [35] it seldom fails to appear. It is true of the world, as of an individual, that "Necessity is the mother of invention."
In the mean time Torricelli had performed his famous barometer experiment, and Otto von Guericke had astonished princes with proofs of the pressure of the air. ”

“ What is true of a man is true of an engine. The work the engine does, as well as the heat it produces, comes from the heat of the fuel in the furnace. Mayer found that one hundred pounds of coal in a good working engine produces the same amount of heat as ninety-five pounds in an engine that is not working. In the working engine the heat of the five pounds of coal is used up in the work of running the engine, and therefore does not heat the engine. Heat that is used in running the engine is no longer heat, but work. ”

“ When the telephone was invented it was commonly remarked that it could not take the place of the telegraph in commerce, for the latter gave the merchant some evidence of a business transaction, while the telephone left no sign. There was a time when men feared to trust each other, but now large business deals are made by telephone; products of the farm, the factory, and the mine are bought and sold in immense quantities without a written contract or even the written evidence of a telegram. Thus the telephone has developed a spirit of business honor. ”

“ Before the inventions of James Watt made it possible to use steam-power, factories were built near falling water, so that water-power could be used. But the steam-engine made it possible to build great factories wherever a supply of water for the boilers could be obtained. Cities were built around the factories. Cities already great became greater. With the growth of cities the need of a new means of producing light and power made itself felt. Electricity promised to become the Hercules that should perform the tasks of the modern world.
Discovery gave way to invention. ”

“ They were married and lived in rooms at the Royal Institution. No poet ever loved more tenderly than Faraday. Truly, science does not dry up the heart's blood. At the age of seventy-one he wrote to his wife while absent from home for a few days: "Remember me; I think as much of you as is good for either you or me. We cannot well do without each other. But we love with a strong hope of love continuing ever." ”

“ Davy had proved that, in the voltaic battery, something must be used up to produce the current—the mere contact of the metals is not sufficient. Faraday had said that in no case is there a production of electrical power without something being used up to supply it. Mayer stated clearly this law of energy when he said that energy cannot be created or destroyed, but only changed from one form to another.
And yet inventors have not learned the meaning of this law. They continue trying to invent perpetual-motion machines—machines that will produce work from nothing. ”

“ Light, we know, is made up of waves, and we cannot think of waves going through empty space. There must be something between the sun and the earth. That something through which the light of the sun comes to the earth we call the ether. It is the ether that carries the light across the vacuum in the light bulb as well as from the sun to the earth. Electric waves used in wireless telegraphy go through this same ether. The light of the sun is made up of the same kind of waves, and we do not think it strange because it is so common. ”

“ For a long time after men had learned the use of the furnace and could produce great heat, the greatest cold known was that of the mountain-top. Men wondered what would happen if air could be made colder than the frost of winter, but knew not how to bring about such a result. They wondered what things could be frozen that remain liquid or gaseous even in the cold of winter.
The first artificial cold was produced by a mixture of salt and ice, such as we now use in an ice-cream freezer. In time men learned other ways of producing great cold and even to manufacture ice in large quantities. ”

“ Neither can man create energy; he can only direct its changes as the engineer, by the motion of his finger in opening a valve, sets the locomotive in motion. He does not move the locomotive. He directs the energy already in the steam. [87]
Since the time of Galileo, men had caught now and then a glimpse of this great law. Galileo had stated his law of machines; that, when a machine does work, a man or a horse or some other power does an equal amount of work upon the machine. Count Rumford had performed his experiment with the cannon, showing that heat is produced by the work of a horse. ”

“ Men sought for truth where truth could not be found. They looked within their mouldy manuscripts and asked, "What do the great philosophers say ought to happen?" instead of looking at nature and asking, "What does happen?" And when a man arose who dared to doubt the authority of the old masters and turn to nature to find out the truth, all the weapons at the command of the old school were hurled against him. ”

“ Attempts were made early in the century to use a battery current for power, but they failed because of the cost and the fact that no good working motor had been invented.
Light and power were needed. Electricity could supply both. But how overcome the difficulty of cost, and produce an electric current from burning coal or falling water? For answer man looked to the great discovery of Faraday and his "new electrical machine." Inventors in Germany, France, England, Italy, and America made improvements until from the disk dynamo of Faraday there had evolved the modern dynamo. ”

“ He knew that lightning is far more powerful than any battery of Leyden jars, and yet to test the truth of his theory, that lightning is an electrical discharge, he was about to draw the lightning to his hand. He knew little of conductors of electricity. Whether the cord would draw little or much of the "electric fire" he knew not. So far as he knew he was toying with death.
The kite was made of two light strips of cedar placed crosswise, and a large silk handkerchief fastened to the strips. A sharp wire about a foot long was fastened to one of the strips. ”

“ In no case will a machine do work without receiving an equal amount of work.
Torricelli and the Barometer
Galileo had a pump which he found would not work when the water was thirty-five feet below the valve. He thought the pump was injured, and sent for the maker. The maker assured him that no pump would do better. This led Torricelli, one of Galileo's pupils, to the discovery of the barometer. Men had said that water rises in a pump because nature abhors a vacuum. Torricelli believed that air-pressure and not nature's "horror of a vacuum" is the cause of water rising in a pump. ”

“ Volta had contended that the contact of the metals in a battery produces a current, that the liquid merely carries the electricity from one metal plate to the other. But Davy proved that there can be no current without chemical action. Whenever we put two metals in an acid or other solution that will dissolve one metal faster than the other, and connect the metals with a wire, an electric current is produced. If we use water with silver and gold, there is no current, because water will not dissolve either the silver or the gold. ”

“ If it were possible for us to live in such a climate, and the world were cooled to the temperature of liquid air, we should have a curious world. Watch-springs might be made out of pewter, bells of tin, and piano wires of solder, for these metals are made stronger by the extreme cold of liquid air. There would be no air to breathe. Oceans and rivers would be frozen solid, and the air would form a liquid ocean about thirty-five feet deep. This ocean of liquid air would be kept boiling a long time by the heat of the ice beneath it, for ice is hot compared with liquid air. ”

“ We have seen that the latter half of the nineteenth century was a time of invention. It was a time when the great discoveries of many centuries bore fruit in great inventions. It was thought by some scientists that all the great discoveries had been made, and that all that remained was careful work in applying the great principles that had been discovered. ”

“ Air-Ships
For centuries men sailed over the water at the mercy of the wind. The sailing vessel is helpless in a storm. Early in the nineteenth century they learned to use the power of steam for ocean travel, and the wind lost its terrors. Late in the eighteenth century men learned to sail through the air in balloons even more at the mercy of the wind than the [174] sailing vessels on the ocean. More than a hundred years later they learned to propel air-ships in the teeth of the wind. ”

“ To make a car run on a single rail, with its weight above the [202] rail, was impossible until the use of the gyroscope was discovered. In the monorail-car invented by Brennan (Fig. 104) there are two gyroscopes, each weighing fifteen hundred pounds, driven at a speed of three thousand revolutions a minute by an electric motor. Each gyroscope wheel with its motor is mounted in an air-tight casing from which the air is pumped out. The wheel will run much more easily in a vacuum than in air, for the air offers very great resistance to its motion. ”

“ A glider is an aeroplane without a propeller. With it one can cast off into the air from a great height and sail slowly to the ground. Before attempting to use a motor and propeller, the Wrights learned to control the glider perfectly. They had to learn how to prevent its being tipped over by the wind, and how to steer it in any direction. This took years of patient work. But the problem was conquered at last, and they attached a motor and propeller to the glider, and had an air-ship under perfect control and with the speed of an express-train. ”

“ It took a long time to discover that the spinning top is a useful machine. It is useful because of its steady motion, because it is difficult to turn over. It was discovered by Newton long ago that every moving object tries to keep on in the direction in which it is moving. A moving object always requires some force to change its direction. The spinning top is a beautiful illustration of this principle. The top that is most useful is the gyroscope top (Fig. 103) . It is mounted on pivots so arranged that the top can turn in any direction within the frame that supports it. ”

“ From the time of Volta to the time of Faraday the only means of producing an electric current was the "voltaic battery," so called in honor of Volta. The voltaic cell is the simplest form of electric battery. In this cell the zinc and copper plates are placed in sulphuric acid diluted with water. As the acid eats the zinc, hydrogen gas is formed. This gas collects in bubbles on the copper plate and weakens the current. The aim of inventors was to produce a steady current, to devise a battery in which no gas would collect on the copper plate. ”

“ A transformer is simply two coils of wire wound on an iron core. The simplest transformer is the form used by Faraday when he discovered electromagnetic induction. If instead of making and breaking a circuit that flows only in one direction as Faraday did, we cause an alternating current to flow through one of the coils, which we may call the primary, each time the current changes direction in the primary the magnetic field is reversed—that is, the end of the coil which was the north pole becomes the south pole. ”

“ His greatest improvement, however, was in making the dynamo self-regulating, so that the dynamo will send out the strength of current that is needed. Such a dynamo will send out more current when more lights are turned on. Whether it supplies current for one light or a thousand, it sends out just the current that is needed—no more, no less. It will do this if no human being is near. An attendant is needed only to keep the machinery well oiled and see that each part is in working order. Edison brought about this improvement by his improved method of winding. ”

“ The man is so absorbed in the present that he cares little for the past. Not so with the boy. He cares for the history of inventions, and in this he is wiser than the man, for it is only by a study of its origin and growth that we can understand the larger significance of a great invention. ”

“ The current from one large dynamo may light streets and houses, and at the same time run a number of motors in factories or street-cars at great distances apart. A central-station dynamo may run the motors that propel hundreds of street-cars. Dynamos at Niagara furnish current for motors in Buffalo and other cities. One great scientist, who no doubt fore-saw the wonders of electricity which we know so well to-day, said that the greatest discovery of the nineteenth century was that the Gramme machine is reversible. ”

“ The voltaic cell, on the other hand, furnishes a large quantity of electricity at low pressure, as a street may be flooded by a broken water-main though the pressure is low. In fact, the quantity of electricity required to decompose a grain of water is equal to that discharged in a stroke of lightning, while the action of a dilute acid on the one-hundredth part of an ounce of zinc in a battery yields electricity sufficient for a powerful thunder-storm. ”

“ A moving magnet causes a current to flow in a coil, but a magnet at rest has no effect. A moving magnet is equal to a battery. In Faraday's experiments a current was induced in a coil of wire by moving a magnet in the coil or by [99] making and breaking the circuit in another coil wound on the same iron core. A current was induced in a metal disk by revolving it between the poles of a magnet. In every case there was motion in a magnetic field, or the field itself was changed. A changing magnetic field is equal to a moving magnet. ”