"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 circumstance 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 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. For this purpose he founded the Royal Institution. 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 Institution, 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.