212 Capt. Sir A. Noble. [June 21, 



in other directions, is a fatal objection to the employment of gun- 

 cotton for propelling purposes. 



Turning now to cordite ; cordite consists, as is well known, of 

 nitro-glycerine and gun-cotton as its main ingredients. As now 

 made it contains 37 per cent, of gun-cotton (trinitro-cellulose with a 

 small proportion of soluble gun-cotton), 58 percent, of nitro-glycerine, 

 and 5 per cent, of a hydrocarbon known as vaselin. On account of 

 the importance of this explosive, I have made numerous experiments, 

 both with large and small charges, to determine the relation of the 

 tension to the density of the charge. Up to densities of 0'55 the 

 relation may be considered to be very approximately determined ; 

 above that density, although many determinations have been made, 

 these determinations have shown such wide variations that they 

 cannot, until certain discrepancies are explained, be assumed as at all 

 accurate. 



The average results of some of the analyses of the permanent gases 

 are given below : 



The first four analyses were made from experiments with the 

 earlier samples of cordite when tannin formed an ingredient of 

 cordite. They are not, therefore, strictly comparable with the later 

 analyses. There appears also to be a difference in the transformation, 

 slight but decided, which the same cordite experiences, dependent 

 upon the diameter of the cord, and this difference is shown at once in 

 the analyses, in the volume of permanent gases, in the heat developed, 

 and, I think, in the amount of aqueous vapour formed. 



The following are some of the analyses : 



VI. 



Pressure per square inch. 



/ " > 



0-048 Cordite. 0'255 Cordite. 



In the whole of these analyses the water formed by the explosion 

 smelt strongly of ammonia. 



The quantity of permanent gases measured, under the same con- 

 ditions as in the case of gun-cotton, was found to be 



For the earlier cordite, 655 vols. 



For the present service cordite, O255 in. in diameter, 692 vols., 

 and for that 0'048 in. in diameter, 698 vols. In the two latter 

 samples the aqueous vapour was determined, and was found to 



