456 Intelligence and Miscellaneous Articles. 



measuring the maximum pressure in the tube. The volumetric 

 analysis of the gaseous products was completed by the absolute 

 measurement of the volume occupied, at 0° temperature and normal 

 pressure, by the gases from a determined weight of explosive. 

 These are the principal results obtained : — 



(1) Gun-cotton. — The composition and volume of the gases were 

 determined under four conditions, differing by the mean density of 

 the products. It follows from the numbers of experiment that, 

 when the density augments, the proportion of carbonic oxide pro- 

 gressively diminishes, that of carbonic acid increasing. 



The following formula;, which very well represent the composi- 

 tion of the gases produced under the four conditions of our experi- 

 ments, show what is the law according to which the decomposition 

 of the substance is modified by the pressure ; they correspond to 

 the decomposition of 1 equivalent of gun-cotton (C 48 H 29 N n 84 ) : 

 Density. Formula of decomposition. 



0-010 .... 3300 + 1500, + 8H+11N + 21HO 

 0-023 .... 30GO + 18OO 2 + llH + llK" + 18HO 

 0-200 .... 27CO + 21C0 + 14H + ll]S' + 15HO 

 0-300 .... 28CO + 220Oa + 15H + llN + 14HO 

 They indicate that, for increasing values of the density of loading, 

 the carbonic oxide and carbonic acid tend to be produced in equal 

 volumes, according to the formula 



C 48 H 29 N u 84 =24CO + 24C0 2 +17H+llN + 12HO; 

 and it may be assumed that this formula represents sensibly the 

 mode of decomposition realized under ordinary conditions in prac- 

 tice, in which gun-cotton is generally used in very dense charges. 



(2) Gun-cotton mith Nitrate of Potass. — The analysis of the gases 

 shows that the oxidation of the explosive is incomplete under low 

 densities of charge, although the proportion of the oxidant may be 

 considerably higher than that which theoretically corresponds to 

 complete combustion ; but at 0-3 and higher densities carbonic oxide 

 disappears, and the decomposition of the mixture takes place regu- 

 larly according to the formula 



48 H 29 N n O 84 +12(NO 5 K0)=36C0 o +23]N T +19O-h29H0 

 + 12C0 2 KO. 



(3) Gun-cotton ivith Nitrate of Ammonia. — The combustion is 

 complete, even under low densities of charge. The results of ana- 

 lysis show that the reaction corresponds to the equation 



C 4 8 H 29 N n 84 +22(NO 6 H,]N T H3)=48C0 2 + 55N + ll7HO + 3O, 

 the first member of which represents exactly the composition of the 

 mixture (deducting the humidity and the saline residue contained 

 in the gun-cotton); while the second member is established on the 

 supposition that the decomposition of the nitrate generates, in one 

 of the modes studied by M. Berthelot, oxygen, nitrogen, and water. 



(4) Nitroglycerine. — According to a remark by M. Berthelot, the 

 composition of the products of an explosion can be foreseen when 

 the explosive contains sufficient oxygen to transform the elements 



