1894.] Researches on Explosives. 213 



amount to 20'257 grams for the 0'255-in. cordite, and to 20*126 grams 

 for the 0'048-in. cordite ; or, stating the result per gram, these 

 figures are respectively equivalent to 0'1563 gram, or 194 c.c. 

 aqueous vapour, and to O1553 gram, or 192'5 c.c. per gram of cordite. 



Hence the total gaseous products generated by the explosion of 

 cordite amount per gram to 886 c.c. for the 0'255-in. cordite, and to 

 890'5 c.c. for the 0'048-in. cordite, the volumes being, of course, taken 

 at C. and 760 mm. atmospheric pressure. 



The heat generated was found to be : For the earlier cordite, 

 1214 gram-units water fluid ; for the service 0'255-in. cordite, 1284 

 gram-units water fluid or 1189 units water gaseous; for the service 

 0'048-in. cordite, 1272 units water fluid or 1178 units water gaseous. 



From my very numerous experiments on erosion I have arrived at 

 the conclusion that the principal factors determining its amount are : 

 (1) the actual temperature of the products of combustion, (2) the 

 motion of these products. But little erosive effect is produced, even 

 by the most erosive powders, in close vessels, or in those portions of 

 the chambers of guns where the motion of the gas is feeble or nil ; 

 but the case is widely different where there is rapid motion of the 

 gases at high densities. It is not difficult absolutely to retain without 

 leakage the products of explosions at very high pressures, but if there 

 be any appreciable escape before the gases are cooled they instantly 

 cut a way for themselves with astonishing rapidity, totally destroying- 

 the surfaces over or through which they pass. Among all the ex- 

 plosives with which I have experimented I have found that where 

 the heat developed is low the erosive effect is also low. 



With ordinary powders, the most erosive with which I am ac- 

 quainted is that which, on account of other properties, is used for the 

 battering charges of heavy guns : I refer to brown prismatic powder. 

 The erosive effect of cordite, if considered in relation to the energy 

 generated by the two explosives, is very slightly greater than that of 

 brown prismatic, but very much higher effects can, if it be so desired, 

 be obtained with cordite, and, if the highest energy be demanded, the 

 erosion will be proportionally greater. There is, however, one curious 

 and satisfactory peculiarity connected with erosion by cordite. 

 Erosion produced by ordinary gunpowder has the most singular effect 

 on the metal of the gun, eating out large holes and forming long 

 rough grooves, resembling a ploughed field in miniature, and these 

 grooves have, moreover, the unpleasant habit of being very apt to 

 develop into cracks ; but with cordite, so far as my experience goes, 

 the erosion is of a very different character. The eddy holes and long 

 grooves are absent, and the erosion appears to consist in a simple 

 washing away of the surface of the steel barrel. 



Cordite does not detonate ; at least, although I have made far more 

 experiments on detonation with this explosive than with any other, 



