Part 4 (2/2)

Count Rumford's Experiment with the Cannon

While in the service of the Duke of Bavaria, it became his duty to organize the field artillery. To provide cannon for this purpose, he erected a foundry and machine-shops. Being alert for any unusual fact relating to heat, he observed the very high temperature produced by the boring of the cannon. He was eager to learn how so much heat could be produced. For this purpose he took a cannon in the rough, as it came from the foundry, fixed it in the machine used for boring, and caused the cannon to be turned by horses while a blunt borer was forced against the end of the cannon. He first tested the temperature of the metal itself as it turned. Then he surrounded the end of the cannon with water in an oblong box fitted water-tight (Fig. 20).

[Ill.u.s.tration: FIG. 20--COUNT RUMFORD'S EXPERIMENT WITH THE CANNON, MAKING WATER BOIL WITHOUT FIRE The horses make the water boil by walking around the track; the work the horses do is changed into heat by the friction of the drill.]

The cannon had been turning but a short time when he found by putting his hand in the water that heat had been produced. In two hours and thirty minutes the water actually boiled. Astonishment was expressed in the faces of the bystanders on seeing so large a quant.i.ty of water heated and actually made to boil without any fire.

”Heat,” Count Rumford said; ”may thus be produced merely by the strength of a horse, and, in case of necessity, this heat might be used in cooking victuals. But no circ.u.mstance can be imagined in which there is any advantage in this method of procuring heat, for more heat might be obtained by burning the fodder which the horse would eat.” The meaning of this last remark was not understood until the time of Robert Mayer, about fifty years later. 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 Inst.i.tution 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. For this purpose he founded the Royal Inst.i.tution. Here he intended that men skilled in discovery should gain new knowledge that would add to the comfort and happiness of the people.

Davy

In the English coal-fields many accidents due to the burning of fire-damp had occurred. Fire-damp is caused by gas issuing from the coal. On the approach of a flame this gas catches fire, and as it burns it produces a violent wind, driving the flame before it through the mine. Miners were scorched to death, suffocated, or buried under ruins from the roof. Hundreds of miners had been killed. No means of lighting the mines in safety had been devised. Sir Humphry Davy, Professor of Chemistry in the Royal Inst.i.tution, was appealed to. After many experiments he devised a ”safe lamp,” which was a common miner's lamp enclosed in a wire gauze. This proved a perfect protection from fire-damp, and the Davy safety lamp has been used by miners the world over for more than a century.

But Davy's best work was with the electric battery. Some of the facts most familiar to us were discovered by him. 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.

Davy discovered the metal, pota.s.sium, by means of his electric battery.

Pota.s.sium is found in common potash and saltpetre, and, when separated, is a very soft metal. The newly discovered metal aroused great interest in other countries. When Napoleon heard of it, he inquired impetuously how it happened the discovery had not been made in France. On being told that in France there had not been made an electric battery of sufficient power, he exclaimed: ”Then let one be instantly made without regard to cost or labor.” His command was obeyed, and he was called to witness the action of the new battery. Before any one could interfere he placed the ends of the wires under his tongue and received a shock that nearly deprived him of sensation. On recovering he left the laboratory without a word, and was never afterward heard to refer to the subject.

Davy made many great discoveries, but the greatest was his discovery of Faraday.

A journey on the Continent with Davy was an event in the life of Faraday, who up to that time had never to his own recollection travelled twelve miles from London. On this journey he met Volta, whom he describes as ”an hale elderly man, very free in conversation.” He visited the Academy del Cimento, in Florence, and wrote: ”Here was much to excite interest; in one place was Galileo's first telescope, that with which he discovered Jupiter's satellites. It was a simple tube of wood and paper, about three and a half feet long, with a lens at each end. There was also the first lens which Galileo made. It was set in a very pretty frame of bra.s.s, with an inscription in Latin on it.”

Faraday crossed the Alps and the Apennines, climbed Vesuvius, visited Rome, and _saw a glow-worm_. The last he thought as wonderful as the first.

Shortly after his return to London he fell in love. Now, Faraday had determined that he would not be conquered by the master pa.s.sion. In fact, he had written various aspersions on love, of which the following is a sample:

”What is the pest and plague of human life?

And what the curse that often brings a wife?

'Tis Love.

What is't directs the madman's hot intent, For which a dunce is fully competent?

What's that the wise man always strives to shun, Though still it ever o'er the world has run.

'Tis Love.”

But he reckoned not with his own heart. It is not long until we find him writing to Miss Sarah Barnard, a bright girl of twenty-one: ”You have converted me from one erroneous way, let me hope you will attempt to correct what others are wrong.... Again and again I attempt to say what I feel, but I cannot. Let me, however, claim not to be the selfish being that wishes to bend your affections for his own sake only. In whatever way I can minister to your happiness, either by close attention or by absence, it shall be done. Do not injure me by withdrawing your friends.h.i.+p or punish me for aiming to be more than a friend by making me less.”

They were married and lived in rooms at the Royal Inst.i.tution. 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.”

<script>