248 DISCOVERY OH. 



oxy-acetylene welding. It provides another example 

 of a substance discovered by scientific experiment 

 before it became an important commercial product. 

 When it was discovered by Frederich Wohler in 1862, 

 and acetylene gas was produced from it, little importance 

 was attached to the fact, partly, perhaps, on account of 

 the great expense of its preparation. During the past 

 few years, however, acetylene has assumed commercial 

 importance owing to the development of the electric 

 furnace constructed by Prof. Moissan in 1892, in which 

 calcium carbide can be produced readily and cheaply 

 from lime and carbon in the form of coke. The dis- 

 covery was made independently by an American chemist, 

 Willson, who was trying to produce metallic calcium 

 by heating a mixture of coke and lime in an electric 

 furnace. By the addition of water, the grey mass thus 

 obtained is rapidly decomposed into acetylene and 

 lime ; and as by various mechanical devices the flow 

 of water upon the carbide can be regulated, a convenient 

 means of producing any quantity of the gas for illumin- 

 ating purposes is obtained. 



In 1895, M. Le Chatelier found that when acetylene 

 was burnt with an equal volume of oxygen gas, a tempera- 

 ture was obtained nearly two thousand degrees Fahr. 

 higher than that of the oxy-hydrogen flame ; and it 

 was suggested that the use of acetylene in blow-pipes 

 would be of great value in the production of high tempera- 

 tures in the laboratory. A few years later such blow- 

 pipes were applied industrially for oxy-acetylene welding 

 of metals, and they are now used in thousands of work- 

 shops for this purpose. There is not a stage in this 

 story of the application of a substance to the service 

 of man but is directly dependent upon laboratory 

 studies in chemistry. 



