788 POPULAR SCIENCE MONTHLY. 



gas, which was readily ignited and burned with its characteristic 

 sooty flame. 



Regarding the illuminating power of acetylene, a proper burner 

 using five cubic feet per hour will give from two hundred to two 

 hundred and forty candle power. Five cubic feet of ordinary gas 

 give from fifteen to thirty candle power; that is, a cubic foot of 

 acetylene will give about eight times as much light as the same 

 amount of coal or water gas. Indeed, it is claimed by Prof. Lewes 

 and others that the formation of acetylene in the ordinary gas 

 flame accounts for the latter's luminosity, and it has been pro- 

 posed to enrich water gas by the addition of a small amount of 

 acetylene ; but so much of the latter was found necessary to pro- 

 duce any appreciable result as to render the process impracticable. 

 Acetylene requires a much larger amount of air for complete com- 

 bustion than does ordinary gas. This is a distinct disadvantage, 

 as the large amount of air cools the flame, and thus diminishes 

 its luminosity. The temperature of the acetylene flame is about 

 1000° C, that of an ordinary flat coal-gas flame being 1360° C. 



The present rise into prominence of acetylene, which up to 

 1888 was simply a laboratory product, is due to the discovery of 

 the formation of calcium carbide in the electric furnace. There 

 is some controversy as to who first made this discovery, but the 

 honors seem to belong to Mr. T. L. Wilson, of the Wilson Alumi- 

 num Works. In 1888 Mr. Wilson began a series of experiments 

 with the electric furnace for reducing refractory ores ; during 

 one of these a curious, dark-brown, dense mass was formed, whose 

 immersion in water produced a violent evolution of gas, which 

 upon investigation proved to be acetylene. A French chemist, 

 Moissan, independently discovered the process, and reported it 

 at the meeting of the French Academy, in December, 1892. But 

 as Mr. Wilson sent samples of the carbide to Lord Kelvin in 

 the summer of 1892, for examination, he seems to have pre- 

 ceded Moissan, at any rate in announcing his discovery. All the 

 alkaline earths form carbides in a similar way, which, when 

 treated with water, give off acetylene. It may be interesting to 

 note, in passing, that by means of the electric furnace, a carbide 

 of silicon has recently been obtained, which under the name of 

 carborundum is coming to be used extensively as a polishing and 

 grinding material. It is extremely hard (scratching rubies) and 

 is said to wear well. Another interesting product is the carbide 

 of titanium, the hardness of which is sufficient to scratch the 

 diamond. This discovery of the ready formation of carbides 

 under the great heat of the electric furnace is of special interest 

 to the geologist, as bearing on the theory that these carbides are 

 present in large quantities in the interior regions, to which water 

 must occasionally penetrate ; the resulting generation of gases 



