442 Colonel Sir Frederic L. Nathan [Jan. 29, 



jelly in preserving the stability of cordite, and it was discovered that 

 mineral jelly contained constituents which had the valuable property of 

 combining with the decomposition products (the result of prolonged 

 storage of cordite at high temperatures) to form stable bodies, thus 

 removing these decomposition products, which undoubtedly exert a 

 deteriorating influence on the cordite, from their sphere of action. 



When Abel was engaged on his researches in connection with the 

 production and properties of guncotton, it was obvious to him that 

 some test of a chemical nature was required, in order to ascertain 

 whether or not the finished guncotton had been thoroughly purified 

 in manufacture. It will be remembered that accidents occurred in 

 the early days of its production because this purification had not 

 been carried sufficiently far. The test which he devised was based 

 on the principle that if guncotton be subjected to an elevated tem- 

 perature, traces of oxides of nitrogen will be given off, and will 

 reveal their presence by acting on a suitable reagent. 



The test is carried out by heating guncotton in a test tube placed 

 in a water bath, and suspending over it a strip of moistened filter 

 paper impregnated with potassium iodide and starch. If the purifica- 

 tion of the guncotton has not been sufficient, the discoloration of 

 the test paper takes place early ; as the result of experience Abel 

 fixed a time before which no reaction should take place. This test, 

 known as the x\bel heat test, is a test for the purity of guncotton, 

 and of nitroglycerine, and of freshly made explosives containing either 

 one or both of these ingredients. For this purpose no test has yet 

 been devised which equals it. But it was never intended to be, and 

 is not, a quantitative test, and is therefore only a rough guide, though 

 a very useful one, as to the stability of an explosive which has been 

 in store for more or less prolonged periods, or under more or less 

 adverse conditions. 



Smokeless powders of the types dealt with are all subject to 

 deterioration, and there is very little doubt that this deterioration is 

 for any given explosive a function of the temperature of storage. 

 The higher the temperature, the more rapid the deterioration. 



The necessity, therefore, of some quantitative test which would 

 enable a judgment to be formed as to the extent of deterioration 

 suffered by any given sample of cordite is obviously of great import- 

 ance, because such a test would afford the means of determining 

 how much longer it would be safe to store any given batch of 

 cartridges or lot of cordite at any given temperature. Any such test 

 must be a heating test, and it must be possible to co-relate the 

 temperature and duration of the test with any given temperature and 

 duration of storage. The rate of deterioration as a function of the 

 temperature was determined by Dr. Will for guncotton, and later by 

 Dr. Robertson at Waltham Abbey for nitroglycerine. From these 

 and other experiments carried out at Waltham Abbey, a factor of 

 increase in rate of deterioration of cordite with increase of tempera- 



