550 MM. Pelouzc and Maurey on Gun-cotton. 



arrives at the conclusion that the problem will only be solved 

 when cannon have been made so strong that the destructive effect 

 may be neglected. This is our opinion also ; but it is impossible 

 to enter on this path when we are stopped by the objection of 

 spontaneous explosion, which, we think, rules the entire question. 



VI. Summary. 



In spite of the differences existing between the method of Ge- 

 neral von Lenk and that followed for seven years at the Bouchet 

 powder-works, the same gun-cotton is obtained in both cases, 

 except as regards 2 per cent, of a silicate, which is found in the 

 gun-cotton taken as a type of the Hirtenberg manufacture. 



This silicate was not met with in the gun-cotton proceeding 

 from an English manufacture established on the pattern of the 

 Hirtenberg one. In none of our experiments did it exert any 

 appreciable influence on the properties of gun-cotton; its addition 

 appeared therefore useless. 



Neglecting this inert substance, all the gun-cottons we ana- 

 lyzed, Austrian, English and Erench, presented the same per- 

 centage composition. 



German chemists having adopted a formula for General von 

 Lenk's cotton which does not agree with our analyses, we re- 

 peated them a great number of times, and compared them, so 

 as to retain no doubt about our new formula. 



Another passage of their Report gives 136° as the lowest 

 temperature at which the Hirtenberg gun-cotton explodes. This 

 is a point in which our experiments compel us to differ from 

 them. In fact, this gun-cotton, like the Bouchet, produced 

 several explosions at a temperature of 100°. Once, even, gun- 

 cotton made at Paris by the Lenk method, and perfectly washed, 

 exploded at 47°. 



By sufficiently prolonging the action of a temperature of 80°, 

 60°, and 55°, we have observed decompositions of the same 

 kind in the Austrian and in the Erench gun-cotton. 



Erom this we are convinced that with time the first must un- 

 dergo the same decompositions as the second. 



Of twenty-eight specimens of the Bouchet manufacture which 

 we have examined after a lapse of seventeen years, sixteen had 

 decomposed at the ordinary temperature. This explains the 

 spontaneous combustions in consequence of the elevation of 

 temperature which must take place in large masses. 



We have observed the same ballistic force in the two kinds of 

 gun-cotton. 



The bursting property which led to the rejection of gun-cotton 

 in the Erench artillery, appears to be as energetic in the case of 

 the Austrian gun-cotton. 



