496 



POWDERS WITH A NITRATE BASE. 



principal nations would fluctuate, according to Debus. These 

 relations expressed in weights represent ; 1616 grms. of nitre, 

 252 grms. of carbon, 224 grms. of sulphur; in all, 2092 grms., 

 which makes per kilogramme 772'5 grms. nitre, 120-5 carbon, 

 107 sulphur. 



It should be observed that in this estimate three to four per 

 cent, of matter are neglected, represented by moisture (I'O), ash 

 (0*2 to 0-3), and especially by the hydrogen (04 to 0'5) and 

 oxygen (1'5 to 2*5) of the charcoal. The moisture and ash 

 have little influence ; but the hydrogen and oxygen of the 

 charcoal modify sensibly the volume of the gases. They increase 

 above all the heat liberated, to such a degree, that the difference 

 between the latter calculated from the weight of carbon sup- 

 posed pure and the real heat amounts at least to a tenth, and 

 with some kinds of charcoal might even rise to the fourth of 

 the former quantity (see p. 488). 



9. Final state. We are indebted to Noble and Abel for 

 a long and important work on this question. They effected the 

 combustion of powder in a closed vessel ; a condition which is 

 not quite the same as that of the combustion of powder in fire- 

 arms, on account of expansion, and also of the action on the 

 walls of the vessels, with the formation of iron sulphide, a com- 

 pound which was produced in very considerable quantities in 

 their experiments. The mean density of the products of combus- 

 tion varied in their experiments from O'lO to 0'90. The following 

 are the proportions by weight of the products observed : 



