D. CHEMISTRY AND METALLURGY. 69 



that the disintegration produced by liquefaction of one por- 

 tion of the bodies referred to causes ^hem to exert a greater 

 power of aggregation in the parts less exposed to heat. 

 1 A, December 30, 313. 



GUX-C0TT0N IX BISULPHIDE OF CAEBOX. 







According to Dr. Bleekrode, if gun-cotton be first wet with 

 bisulphide of carbon (a highly inflammable liquid), and an 

 electric spark be passed through it, instead of producing an 

 explosion of the cotton, the bisulphide alone is set fire to, the 

 gun-cotton apparently remaining intact among the burning 

 bisulphide, presenting almost the aspect of a mass of snow 

 slowly melting away. The experiment may be varied by 

 using either benzine or alcohol instead of the bisulphide, and 

 igniting it afterward with any flame. All these liquids yield 

 the same result, and there is no danger in the experiment, 

 even if large quantities are used. This curious phenomenon 

 is explained by Dr. Abel, who says that " these results indi- 

 cate that if, even for the briefest space of time, the gases re- 

 sulting from the first action of heat on gun-cotton upon its 

 ignition in open air are impeded from completely enveloping 

 the burning extremity of the gun-cotton twist, their ignition 

 is prevented; and as it is the comparatively high tempera- 

 ture produced by their combustion which effects the rapid 

 and more complete combustion of the gun-cotton, the mo- 

 mentary extinction of the gases, and the continuous abstrac- 

 tion of heat by them as they escape from the point of com- 

 bustion, render it impossible for the gun-cotton to continue 

 to burn otherwise than in the slow and imperfect manner, un- 

 dergoing a transformation similar in character to destructive 

 distillation." 



As a practical application of these facts, it is suggested that 

 if gun-cotton be kept in a flask in a layer of benzine or bisul- 

 phide of carbon, the danger of explosion in case of a fire is 

 obviated, since, if the liquid is ignited by any means, the gun- 

 cotton will burn slowly and gradually. When required for 

 use, a brief exposure to the air restores its explosive quali- 

 ties. London, Ediriburg, and Dublin Philoso^jhical Maga- 

 zine, January, 1871, 40. 



