The metallurgy of gold and silver began to improve after the discovery of the Californian deposits in 1848. The stamper battery and amalgamation processes were improved; when sulphide ores were encountered, chlorination processes were developed. Subsequently, in response to demand for a cheaper chemical solvent for low-grade ores, the cyanide and bromide processes were devised. The application of the electric furnace to metallurgy greatly increased the scope of metallurgists' methods. Pichon, in 1853, described a small arc furnace with which he was experimenting, and in 1878 Sir William Siemens built a furnace for reducing iron ores. Moissan made numerous tests of furnaces and smelting methods in the nineties and did much to develop commercial electric smelting. Faure, Cowles, Borchers, De Chalmont, Girod, Heroult, and others invented furnaces, smelting methods, and metallurgical processes. The aluminum, carborundum, acetylene, and other important industries are developments from the electrometallurgy of iron and copper. Zinc, copper, nickel, silver, gold, and platinum plating and the electrodepositing of copper in the form of tubes by the Elmore process are dependent upon the principles of electrometallurgy as is the electrorefining of metals. [Illustration: Copyright, Keystone View Co. EDOUARD BELIN AND THE TELAUTOGRAPH, WHICH TRANSMITS PICTURES BY WIRE] [Illustration: LEE DE FOREST, INVENTOR OF THE OSCILLATING AUDION] [Illustration: AUTOMOBILE WITH RADIO EQUIPMENT FOR LISTENING IN EN TOUR] The physical phenomena of the earth's atmosphere are studied under the science of meteorology. The art of weather forecasting is as old almost as mankind, but only in recent years has it been placed upon a sound basis. Torricelli, in 1643, invented the barometer; Boyle, in 1685, developed it and applied it to measuring gas pressures. The chemists of the eighteenth century, Boyle, Black, Rutherford, Priestley, Scheele, Lavoisier, and Cavendish, all studied the chemistry of the atmosphere. Franklin, in 1749, raised thermometers by kites to measure temperatures. Balloon ascents were made by Jefferies and Blanchard, in 1784, for atmospheric observations. Soundings of the upper air by balloons, kites, and other apparatus have been conducted since the closing years of the nineteenth century. CHAPTER XV MEDICINE AND PHARMACY Medicine was in a state of transition at the beginning of the nineteenth century. The great scientific discoveries of the eighteenth century had carried people away to such an extent that they showed a tendency to exaggerate their bearings upon medicine. The result was a wild diffusion of extravagant speculation and unsubstantial hypotheses.