214 Capt. Sir A Noble. f June 21, 



I have never succeeded in detonating it. With an explosive like 

 cordite, capable of developing enormous pressures, it is, of course, 

 easy, if the cordite be finely comminuted, to develop very high 

 tensions, but, as I have already explained, a high pressure does not 

 necessarily imply detonation. 



The rapidity with which cordite gases lose their temperature, and 

 consequently their pressure, by communication of their heat to their 

 surrounding envelope is very striking. Exploding a charge of about 

 If Ibs. of cordite in a close vessel at a tension of a little over 6 tons 

 on the square inch, or say 1000 atmospheres, I have found that the 

 pressure of 6 tons per square inch was again reached in 0'07 sec. 

 after explosion, of 5 tons in 0"171 sec., of 4 tons in 0'731 sec., of 

 3 tons in 1'764 sees., of 2 tons in 3'523 sees., and of 1 ton in 7*08 sees. 

 The loss of pressure after 1 ton per square inch was reached was, of 

 course, slow, but the figures I have given were closely approximated 

 to in two subsequent experiments. With ordinary gunpowder the 

 reduction of pressure was very much slower, as was to be expected, 

 on account of the charge being much larger ; on account, also, of the 

 temperature of explosion being much lower. 



These experiments are now being continued with larger charges 

 and higher pressures. 



It only remains to give particulars as to ballistics, that is as to the 

 velocities and energies realisable by cordite in the bore of a gun, but 

 these will be most conveniently given with similar details regarding 

 other explosives with which I have experimented. 



The ballistite I have used has, like the cordite, been changed in 

 composition since the commencement of my experiments. The 

 sample I used for my earlier experiments was nearly exactly com- 

 posed of 50 per cent, of dinitro- cellulose (collodion cotton) and 50 

 per cent, of nitro-glycerine. The cubes were coated with graphite, 

 and the nitro-cellulose was wholly soluble in ether alcohol. 



The second sample was nominally composed of 60 per cent, of 

 nitro-cellulose and 40 per cent, of nitro-glycerine. The proximate 

 analysis gave 



Nitro-glycerine 41*62 



Nitro-cellulose 59'05 



as before the whole of the nitro-cellulose was soluble in ether alcohol. 

 The earlier sample gave the following permanent gases under pres- 

 sures of six and twelve tons per square inch respectively. 



