1862.] and Military Applications of Explosions, 489 



the heat developed ; a powerfully explosive effect being consequently 

 produced. 



Explosions are much more frequently the result of chemical de- 

 composition. Several classes of compounds are known, the unstable 

 character of which endows them with explosive properties. Thus the 

 compounds known as the chloride, iodide, and bromide of nitrogen are 

 highly susceptible of instantaneous decomposition ; the very slightest 

 disturbing causes sufficing to destroy the chemical equilibrium which 

 exists between their component particles. Compounds of silver and 

 gold with nitrogen, hydrogen, and oxygen (fulminating silver and gold), 

 and of silver and mercury with a peculiar organic group, generally 

 known as fulminic acid (the fulminates of mercury and silver), are 

 also highly susceptible of sudden, and therefore violently explosive, 

 decomposition. By the action of nitric and nitrous acids upon several 

 organic bodies, compounds of highly explosive characters are pro- 

 duced, their formation resulting from the abstraction (by oxidation) of 

 a proportion of hydrogen-atoms from the original body, and the in- 

 troduction, in their place, of a high oxide of nitrogen. The products 

 of the action of nitric acid upon starch and cotton, in different forms, 

 are the best known of these ; among others, the substances known 

 as nitromannite (obtained by the action of nitric acid upon mannite) 

 and nitroglycerine, or glonoine (the product of the action of nitric 

 acid at low temperature upon glycerine), are remarkable for the 

 violence with which they explode when submitted to friction or con- 

 cussion. One of the most recently-discovered and curious of these 

 explosive organic bodies is the nitrate of diazobenzol, obtained by the 

 action of nitrous acid at a low temperature upon aniline. This sub- 

 stance explodes at least as violently as iodide of nitrogen and ful- 

 minate of silver, if exposed to a heat approaching that of boiling 

 water ; it is, however, far less sensitive to friction than those two 

 bodies. Similarly explosive substances have been quite recently ob- 

 tained by Dr. Hofmann from derivatives of the interesting and im- 

 portant base, rosaniline, the salts of which furnish some of the most 

 beautiful of the colours now obtained from aniline. 



Explosions are most readily produced by establishing chemical 

 action between certain substances, greatly opposed to each other in 

 their properties, and brought together in an intimate state of mix- 

 ture. The substances applicable to the production of such mixtures 

 are, on the one hand, bodies remarkable for their great affinity for 

 oxygen ; and, on the other, compounds containing that element in 

 abundance, and partly, or entirely, in a loose state of combination. 

 To the first class belong the elements carbon, sulphur, and phos- 

 phorus, and compounds of the last two, with readily oxidisable metals ; 

 the second class includes a few of the higher metallic oxides (such as 

 the higher oxides of manganese and lead) and combinations of metals 

 with nitric, chloric, and perchloric acids. Mixtures produced with 

 these two classes of bodies readily ignite, or afford explosions, either 

 upon the direct application of heat, or by submitting them to friction, 



