164 Mr. E. A. Abel on the [Feb. 5, 



soluble salt (e. y. potassium chloride) the well-incorporated mixture being 

 compressed with the aid of the solvent (e. g. water), and then dried, the 

 material is obtained in a condition of great rigidity, the particles being 

 cemented together by the crystallized salt ; it is therefore in a form more 

 favourable to the action of detonation than undiluted gun-cotton sub- 

 mitted to considerably greater compression. 



When the solid substance with which gun-cotton is diluted consists 

 of an oxidizing agent (a nitrate or chlorate), the predisposition to chemical 

 reaction between the two substances so far increases the susceptibility to 

 detonation that, operating in conjunction with the effect of the soluble 

 salt in imparting rigidity to the mixture, it renders the latter quite as 

 sensitive to the detonating action of the minimum fulminate-charge as 

 undiluted gun-cotton is, when highly compressed. This fact has given 

 additional importance to results which the author obtained some time 

 since in availing himself of the facility with which finely divided gun- 

 cotton, as obtained by the pulping process, may be intimately mixed with 

 the proportion of an oxidizing agent (such as potassium nitrate) required 

 to completely oxidize the carbon. If about three fourths of the theoretical 

 requirements of the salts be employed, the resulting products will perform 

 fully the amount of work obtained from a corresponding weight of undi- 

 luted gun-cotton; and as nearly one third of this substance has been 

 replaced in them by material of very much less cost, a considerable advan- 

 tage is gained in point of economy. Moreover the greater rigidity of the 

 compressed masses of " nitrated " gun-cotton, already explained, renders 

 them less susceptible to injury by transport and rough usage than ordinary 

 compressed gun-cotton. 



These compressed mixtures being found quite as sensitive to detonation 

 by fulminate as the pure explosive compound, it became interesting to 

 compare their behaviour with that of the latter, when exposed to the 

 detonation of nitroglycerine. The results demonstrated that they are 

 much more readily susceptible of detonation by it than compressed gun- 

 cotton ; thus, in only one instance was the latter detonated by the explo- 

 sion of 62-4 grammes (two ounces) of nitroglycerine in close contact with 

 it, but that quantity invariably detonated " nitrated " gun-cotton. The 

 same result was obtained with only 31*2 grammes (one ounce) of nitro- 

 glycerine in three out of four experiments ; in the fourth the nitrated 

 preparation was exploded, but without the destructive effect produced in 

 the other experiments ; similar explosions of the substance were deve- 

 loped by means of 15*6 grammes (0-5 ounce) of nitroglycerine. In the 

 case of pure gun-cotton, the results obtained were always either simple 

 disintegration of the mass, or else detonation, if sufficient nitroglycerine 

 were used. 



To ascertain whether the different behaviour of the " nitrate " (and 

 " chlorate ") preparations was due to their greater hardness and rigidity, 

 some corresponding experiments were made with compressed masses pro- 





