342 POPULAR SCIENCE MONTHLY. 



by fire caused by the explosion of a cylinder filled through careless- 

 ness of workmen with a mixture of air and liquid acetylene i. e., 

 with an explosive mixture killing the superintendent and a workman. 

 In the explosion at the regulator factory at New Haven, January, 

 1895, the valve of the cylinder, on which one of two workmen killed 

 was working, broke; a large volume of acetylene escaped and ignited 

 from a lighted candle. In all four cases the explosions were caused 

 by ignorance or carelessness incident to the beginnings of a new in- 

 dustry, and could be avoided by experience and skill. 



It should be stated that in the explosion at Paris all of the full 

 acetylene cylinders were dug out of the ruins unhurt. The same was 

 true at Berlin, where five full cylinders were blown against the 

 wall of the building by the explosion of the condenser, but did not 

 explode. At Jersey City sixty filled cylinders were exposed to the 

 heat of the fire following the explosion ; they were fitted with safety 

 diaphragms of fusible metal; forty-eight remained intact, the acety- 

 lene burning off quietly as it escaped through the fused diaphragm, 

 and twelve exploded, either on account of imperfection of the dia- 

 phragms or stoppage of the air passage leading from the diaphragm. 

 The explosions of liquid acetylene in buildings of consumers have 

 been due in every case to gross carelessness and ignorance on the part 

 of the consumer. 



Although one of the chief points in favor of the liquid acetylene 

 is its portability, yet it can be shown that it is still easier to carry car- 

 bide to the consumer. One cubic metre of acetylene is compressed to 

 two litres in liquid form ; two litres of carbide weigh 4.44 kilogrammes, 

 which will produce a cubic metre and a third of acetylene, reckon- 

 ing three hundred litres to the kilogramme, which is the average guar- 

 anteed yield of carbide. The light tin carbide cans occupy less space 

 and weigh less than the heavy steel cylinders, while the generation 

 of the gas is simple and, with proper generators, perfectly safe. On 

 the other hand, the generators must be cared for, must often be filled 

 with fresh carbide, and from time to time must be cleaned. With 

 the generator system acetylene is as safe as or safer than illuminating 

 gas. Berthelot has shown that at pressures below two atmospheres a 

 vessel filled with acetylene can not be exploded by the explosion of a 

 cap of fulminating mercury within the vessel, nor by heating a wire 

 which extends into the vessel to a white heat by an electric current. 

 The reason is that the acetylene can not explode unless it is decom- 

 posed into its elements, carbon and hydrogen; to decompose it re- 

 quires a certain amount of energy. While the energy of the glowing- 

 wire or of the exploding cap causes a local decomposition at the point 

 of coiitac^, it is not sufficient to spread the decomposition further. 

 Acetylene forms an explosive mixture with air; so does illuminating 



