1894.] Researches on Explosives. 211 



At the temperature of explosion the whole of the water formed is 

 in the gaseous state. It is therefore necessary, in order to obtain the 

 total gaseous volume, to add to the above volumes of permanent gases 

 the equivalent volume of aqueous vapour at the temperature and 

 pressure stated. Now the quantity of water formed by the explosion 

 of 129*6 grams of gun-cotton was found to be 16'985 grams ; hence 

 1 gram of gun-cotton generated 0'1311 gram of water, equivalent to 

 162'6 c.c. of aqueous vapour, and the total volume of gaseous matter 

 at the temperature and pressure stated is for strand gun-cotton 

 852'2 c.c. per gram, for pellet 887'6 c.c. 



The heat measured reached, with strand gun-cotton, 1068 gram- 

 units water fluid, or 988 gram-units water gaseous, while with 

 pellet gun-cotton these figures were 1037 or 957 gram-units respec- 

 tively. 



Pellet gun-cotton made at Stowmarket generated 738 c.c. of 

 permanent gas and 994 units of heat per gram, while dinitro-cellulose 

 containing 12'8 per cent, of nitrogen generated 748 c.c. of gas and 

 977 units of heat, the water in both cases being fluid. 



Gun-cotton, both pellet and strand, I have detonated by means of 

 mercuric fulminate with ease and certainty. The effect of employing 

 this means of ignition in a close vessel is very striking, and the 

 indications of intense heat are much more apparent than when the 

 charge is fired in the ordinary way. This effect is probably partly 

 due to an actual higher temperature, caused by the greater rapidity 

 of combustion. I allude elsewhere to the extreme rapidity with 

 which the gases part with their heat, but this higher heat is, I think, 

 clearly indicated by the surfaces of the internal crusher gauges 

 becoming covered with innumerable small cracks and by thin laminae 

 occasionally flaking off exposed surfaces; but perhaps the most 

 striking proof of the violence of this detonation is shown by its action 

 on a cast-iron shell fired as I have described ; where no detonation 

 takes place the shell is broken into fragments of various sizes, such 

 as are familiar to all acquainted with the bursting of shell ; but when 

 detonation, with gun-cotton, for example, takes place, the whole 

 shell is reduced to very minute fragments, and, what is more remark- 

 able, two-thirds of the total weight are generally in the form of 

 small peas and of the finest dust. 



The ease with which gun-cotton can be detonated renders it unsuit- 

 able for use as a propulsive agent unless this property be in some way 

 neutralised. I have, therefore, made but few experiments in this 

 direction, and shall not further allude to them in this note, as more 

 suitable explosives, explosives also of which gun-cotton is a principal 

 component, have been elaborated, and these not only possess to the 

 full the high ballistic properties of gun-cotton, but are more or less 

 free from the tendency to detonate, which, however useful it may be 



p 2 



