Theoretical temperature = 4425. 

 3122 atm. 



504 POWDERS WITH A NITRATE BASE. 



181-5 atm. 



Permanent pressure = - TT^T, Wltn tne usual reservation. 

 n U'zb 



Theoretical tempera 



Theoretical pressure 



n U'^o 



The five foregoing equations are the only ones which it is 

 necessary to take into account in problems relating to service 

 powder where the whole of the charcoal disappears, as has been 

 said. 



13. However, the study of blasting powder, which contains 

 an excess of charcoal, has led us to consider a fresh reaction, 

 that of charcoal on carbonic acid. This reaction appears due to 

 the previous decomposition of the latter producing free oxygen 

 capable of changing in its turn the carbon into oxide. 



C0 2 = CO + (partial dissociation) absorbs 34*1 ; 

 C -f = CO (oxidation) liberates + 12'9. 



It already plays a part in two of our equations, for it allows 

 of passing from (3) to (2), and from (5) to (4). 



Without dwelling on the intermediate cases, we shall con- 

 sider the hypothesis of a decomposition as far advanced as 

 possible, a hypothesis which never really applies to any but a 

 portion of the substance. 



Take, therefore, the equation 



2KN0 3 + S + 6C = K 2 S + 600 + 2N. 



It represents 153 grms. ; or, for 1 kgm., 105 grms. of sulphur, 

 235 grms. of carbon, 660 grms. of nitre. The products being, 

 360 grms. K 2 S and 640 grms. CO. 



The heat liberated is 9 '8 Cal. at constant pressure, or 114 at 

 constant volume ; or, for 1 kgm., 64 Cal. at constant pressure, 

 or 74*5 Cal. at constant volume. 



The reduced volume of the gases = 66'9 litres ; or, for 1 kgm., 

 437 litres. 



437 atm. 

 Permanent pressure = - nTTf 



Theoretical temperature = 501. 



1304 atm. 

 Theoretical pressure = - . 



The heat liberated is very slight, and the theoretical 

 temperature so low that this reaction can hardly be regarded 

 as explosive. 



14. If the foregoing results be compared from the point of 



