1882.] 



Chemical Iheory of Gunpowder. 



369 



the largest volume of gas and the smallest quantity of heat, if the 

 mixtures are considered which can transform themselves during com- 

 bustion according to equation (8), in which a is put =0. 

 (8.) The product of (9) and (10) divided by 2 x 1000, 



^ > iZ[=lO44O-88-12-O9v 2 + 12O8-39w-15-95?/0 + 993 > 867^-5-O222 3 

 2000 J J J 



= E (11), 



will assume different values for powders of different composition. 

 The energy of a mixture of saltpetre, carbon, and sulphur will be, 

 cceteris paribus, proportional to the volume of gas, and also to the 

 amount of heat produced during its combustion. Hence, the product 

 of the two, E, may be used, according to the proposal of M. Berthelot, 

 as a measure of the relative energies of powders of different com- 

 position. 



(9.) If in equation (8) x is put =16, and a=0, we obtain: 



16(KN0 3 ) +yC+sS= ■^[64 + 8y-16z](K 3 C0 3 ) 

 +A[320-16y+4»](E^SOJ 

 + _ V [_160 + 8y + 12*](K 2 S 2 ) 

 +A[-W+20y+16«](OOjj 

 + 8N 2 (13), 



and from this, if the coefficients of the potassic carbonate, potassic 

 sulphate, and potassic disulphide are put =0, the equations: 



64 + 8y-162=0 (14), 



320-16?/ + 42=0 (15), 



-160 +8^+ 12* =0 (16). 



These equations represent in a plane three sides of a triangle. The 

 co-ordinates of points within this triangle represent quantities of 

 carbon and sulphur, which can, with 16 molecules of saltpetre trans- 

 form themselves according to equation (13), whereas the co-ordinates 

 of points outside this triangle indicate mixtures which cannot do so, 

 such mixtures containing either too much or too little of carbon or 

 sulphur. 



The co-ordinates of points on the sides of the triangle represent 

 mixtures which will burn with the production of two, and those of 

 the points of intersection of two sides with formation of only one 

 potassium salt. 



The two sides represented by equations (14) and (16) intersect in 

 point y =8, and = 8. These values introduced into (13) give : 



I6KNO3+ + 8C + 8S=8K 3 S0 4 +8CO s + 8N 3 . 



VOL. XXXIII. 2 D 



