History.—As a theoretical possibility and laboratory curiosity acetylene has been known for many years. It exists in illuminating gas in fractional percentage and was produced as early as 1876 by scrubbing coal gas with a copper solution. It was prepared on a labora tory scale by Berthelot and Wohler many years ago. Its birth, however, as a commercial pos sibilty occurred 4 May 1892, when calcium car bide was produced In an electric furnace located at Spray, N. C., by the Willson Alum inum Company. This company was experi menting with a view to improving its process for the production of aluminum and was en deavoring to produce metallic calcium to be used as a reducing agent for aluminum oxide. To this end a mixture of calcium oxide (quick lime) and coal tar was fused in an electric furnace in the hope that the carbon would act as a reducting agent, removing the oxygen from the lime, and leaving the calcium free, the metallic calcium to be used in a subsequent step in the process of producing metallic aluminum. The reaction removed the oxygen from the lime, as was expected, but left the calcium in combination with a portion of the carbon in stead of in a free state, and this combination was found to he calcium carbide. The devel opment of the production of calcium carbide has progressed steadily from that date until the present time, most of the development being under the supervision of two of the men who were operating the original furnace and who are still prominently identified with the indus try. There have been revolutionary changes
in the process of manufacturing carbide, espe cially in the size and extent of the operation. The main underlying process, however, of sub jecting lime and carbon to the intense heat, ob tainable only in the crater of an electric arc, has not changed from 1892 to date. Carbide was introduced into Europe shortly after its discovery. European production has developed to a very large extent. The present advance ment in the process is, however, practically all due to American efforts; the foreign manufac turers have followed American practice with out substantial contribution to its progress. The temperature necessary to form calcium carbide is so intense that the process does not lend itself to laboratory methods and as far as is known it has never been produced on a small scale.
Bibliography.— Bowles, J. D., 'Acetylene for Lighting Country Homes,' (Bul. of the University of Missouri, 1910); Claude, G., 'Liquid Air, Oxygen, Nitrogen' (trans. by Cottrell, H. E P., Philadelphia 1913) ; Leeds,