1909] on Gimcotton and Nitroglycerine. 441 



for the same ballistics, and is certainly not greater, if as great as that 

 produced by the best forms of nitrocellulose explosives. 



Although of minor importance to smokelessness, flamelessness is 

 a desirable quality for propulsive explosives to possess. In this 

 respect cordite M.D. is superior to cordite in the case of rifles and 

 machine guns ; unfortunately a suitable ingredient has not yet been 

 discovered which will render smokeless powders flameless in large 

 guns. 



A third ingredient in both natures of cordite, viz., mineral jelly, 

 although present in a comparatively small proportion, is a very 

 important constituent. 



Cordite in the advanced experimental stage consisted of nitro- 

 glycerine and gun-cotton alone, and as their combustion produced no 

 solid residue of any kind, the surface of the bore of the magazine 

 rifle in which the early experiments took place was not fouled in any 

 way. The result was that the cupro-nickel coated bullets, propelled 

 in succession at high velocity through a clean barrel, deposited some 

 of the cupro-nickel in the bore. In order to prevent this a number 

 of substances were incorporated with the nitroglycerine and gun- 

 cotton, with the object of producing a deposit in "the bore, which it 

 was hoped would get rid of the difficulty of metallic fouling. Of all 

 these various substances the one which appeared to answer the pur- 

 pose most satisfactorily was refined vaseline, and this material became 

 the third ingredient of cordite as eventually introduced into the 

 British Service. When the manufacture was commenced on a large 

 scale, vaseline, which is the proprietary name of one of the refined 

 products of the distillation of petroleum, was replaced by mineral 

 jelly, the same material, but in a cruder form. 



The original object with which mineral jelly was introduced was 

 of no importance when cordite was substituted for the black and 

 brown powders used in large guns, but in order to have but one 

 nature of smokeless powder in the service, mineral jelly was added 

 to all cordite whether for use in small arms or artillery. ' Subsequent 

 experience has demonstrated how very fortunate was the selection of 

 this material for rifle cordite, and the extension of its use to all sizes 

 of cordite. 



Mineral jelly is one of the best ingredients it is possible to have 

 in smokeless powders from the point of view of their chemical 

 stability. This important fact, not recognised originally, was brought 

 out in the following way : In order to facilitate the explosion of 

 cordite in blank ammunition for the rifle, it was cut into very thin 

 flakes and the non-explosive mineral jelly was omitted from its com- 

 position. After a comparatively short storage in a hot climate, the 

 stability of the smokeless blank, as it was called, was found to have 

 suffered seriously, whereas the stability of normal cordite containing 

 mineral jelly was not appreciably affected. These facts led to a 

 thorough investigation at Waltham Abbev of the action of mineral 



2 G 2 



