302 



POPULAR SCIENCE MONTHLY. 



classified under the heads of physical mixtures like gunpowder, or 

 chemical compounds like nitroglycerin, and they owe their develop- 

 ment of energy to the fact that, like gunpowder, they are mixtures 

 in which combustible substances such as charcoal are mixed with 

 supporters of combustion such as niter; or that, like chloride of 

 nitrogen, they are chemical compounds, the formation of whose 

 molecules is attended with the absorption of heat; or that, like gun 

 cotton, they are chemical compounds whose molecules contain both 

 the combustible and the supporter of combustion, and whose for- 

 mation from their elements is attended with the absorption of heat; 

 while occupying a middle place between the gunpowder and the 



Gu^■-C^'TT^>^ Factduv. J-'inal i>n:ss. 



gun-cotton class, and possessing also to some degree the properties 

 of the nitrogen-chloride class, are the nitro-substitution explosives, 

 of which melinite, emmonsite, lyddite, and joveite furnish conspicu- 

 ous examples. 



It may lead to a clearer understanding of what is said regarding 

 the applications of explosives to dwell briefly on the methods by 

 which some of them are produced, since, although the raw material 

 in each case is different and the details of the operations vary, the 

 underlying principles of the methods are the same, and a good ex- 

 ample is found in the military gun cotton as made by the Abel 

 process at tho TTiiitorl States Naval Torpedo Station. 



