GUN-COTTON AND AMMONIUM NITRATE. 455 



various inert substances are added so as to render it non- 

 sensitive to shock. This product may be worked with tools, in 

 the manner of ivory, and is very plastic when heated towards 

 150. But it must not be forgotten that it then tends to 

 become sensitive to shock, and that large quantities of such 

 substances might become explosive during a fire, owing to the 

 general heating of the mass and the evaporation of the camphor. 

 Heated celluloid may even explode, when greatly compressed, 

 and press accidents have occurred in factories. When main- 

 tained at 135 in an oven celluloid decomposes quickly. This 

 is not all, for in an experiment made in a closed vessel at 135, 

 and the density of charge 0'4, it ended by exploding, developing 

 a pressure of 3000 kgm. 



It is therefore a substance the working of which calls for 

 certain precautions, though it is not explosive under ordinary 

 circumstances, even with very powerful detonators. 



5. "NITRATED" GUN-COTTON. 



Mixture formed with ammonium nitrate. 



1. We will examine gun-cotton mixed with ammonium 

 nitrate, and also with potassium nitrate, these two products 

 having been studied in a special manner by Sarrau and Vieille. 



We will first observe that gun-cotton 



C 24 H 18 (N0 3 H) U 9 = 1143 grms., 



requires 41 equivalents of oxygen (328 grms.) for complete com- 

 bustion, and that it then develops at constant pressure 

 2633 Cal., the water being liquid'; or s 2488 Gal., the water 

 being supposed gaseous. The volume of oxygen employed is 

 equal to 229 litres; the carbonic acid produced occupying 

 536 litres, the nitrogen 123 litres, and the water vapour 

 (reduced volume) 324 litres. 



2. This being granted, the total combustion by ammonium 

 nitrate corresponds to the formula 



2[C 24 H 18 (N0 3 H) 11 9 ] + 41N0 3 NH 4 = 48C0 2 + 111H 2 + 52N 2 



Or 1640 grms. of nitrate for 1143 of gun-cotton ; in all, 2783 grms. 

 The substance, then, contains in 1 kgm. 589 grms. of nitrate 

 and 411 grms. of gun-cotton, all the products being supposed 

 dry and free from fixed ash. Sarrau and Vieille used 60 parts 

 of nitrate to 40 parts of gun-cotton. The substances were 

 triturated together, 24 parts of water having been previously 

 added to the gun-cotton, then the whole dried at 60. It was 

 ascertained that the combustion of the mixture yielded only 

 carbonic acid and nitrogen, these two gases being in the ratio 

 of 54 : 46 volumes ; the difference between which and the 

 theoretical figures, or 52 : 48, corresponding to the slight 



