10 Messrs, W. Macnab and E. Ristori. [May 10, 



took fire, and the whole quantity was burnt in a few seconds. 

 Though this powder was made of such powerful explosives as 

 nitro-glycerin and nitro-cellulose, and though the amount was so 

 large that, had it been black powder, it would have caused destruc- 

 tion for many miles around, still there was no explosion of any kind ; 

 none of the machinery was in any way damaged, and the wood was 

 barely charred. 



The explosives used in these experiments can be divided into three 

 classes : 



1. Those consisting of nitro-lignin or nitro-cellnlose (not gelati- 

 nised), mixed, or impregnated with a suitable nitrate, a,nd mixed with 

 colouring matters and some other substances for the purpose of re- 

 tarding the rate of combustion. We have taken as samples of this 

 class the EC and the SS powders now commonly used in sporting 

 guns (the EC consisting principally of nitro-cellulose mixed with 

 barium nitrate and a small proportion of camphor, the SS powder 

 consisting of nitro-lignin mixed with barium nitrate and nitro-ben- 

 zene). 



2. Those consisting of purified nitro-lignin or nitro-cellulose gela- 

 tinised by a suitable process, and with or without the addition of 

 nitro-benzene or other suitable nitrates. 



As sample of this class we have taken the BN powder manufac- 

 tured by the French Government, and also the Rifleite and the 

 Troisdorf powder, which are now commonly used for small arms 

 ammunition. (The BN consists mainly of gelatinised nitro-cellul ose ; 

 the Troisdorf also consists of gelatinised nitro-cellulose, but is 

 coated with graphite. Rifleite is also made with gelatinised nitro- 

 cellulose, with the addition, however, of a certain proportion of nitro- 

 benzene). 



3. Those consisting of nitro-cellnlose combined with nitro-glycerin, 

 with the addition of aniline, camphor, vaseline, or other kindred sub- 

 stances. To this class belong cordite and ballistite. 



Cordite contains 58 per cent, of nitro-glycerin, 37 per cent, of 

 gun-cotton, and 5 per cent, of vaseline. 



Ballistite of Italian manufacture contains equal parts of nitro- 

 cellnlose and nitro-glycerin, with the addition of ^ per cent, of 

 aniline. 



Ballistite of German manufacture contains a slightly higher per- 

 centage of nitro-cellulose, and is coated with graphite. 



Besides, for the purpose of these experiments, a series of samples 

 of ballistite were specially made containing nitro-glycerin and 

 nitro-cellnlose in various proportions. 



The experiments were carried out in two closed vessels of different 

 dimensions and construction a large one capable of standing high 

 pressures, and a small one for calorimetric work. 



