MR. ABEL'S RESEARCHES ON GUN-COTTON. 271> 



were made with very carefully purified cotton, obtained an increase of 78 per cent. 

 The increase of weight which, iu other instances, the cotton must have sustained for the 

 attainment of the analytical results quoted, must have been even more various: thus 

 Ransome's results would indicate an increase of weight of only 65'4 per cent., while 

 those of Pjeligot correspond to a gain of 94-4 per cent. 



Other indications of differences in the characters of the products operated upon by 

 different chemists are furnished by statements made with regard to the action of sol- 

 vents upon them. Their solubility in mixtures of alcohol and ether evidently varied 

 considerably ; and in one instance of these earlier experiments (namely those of MM. 

 Mknakde and Domonte in 1846), a description of gun-cotton soluble in ether and 

 alcohol was described as obtained together with a proportion of an insoluble product. 

 The analysis of the latter furnished results which correspond very closely to those 

 demanded by the formula 



BfiCHAMP instituted some researches upon gun-cotton in 1852, in which he obtained, 



by the action of ammonia upon a soluble form of gun-cotton, a substance to which he 



assigned the formula 



C,, K,, Oi;, 4N O5 (C,, H3, 0i„ 4N2 O5), 



viewing it as pyroxylin from which one equivalent of nitric anhydride had been 

 abstracted; he therefore considered that the formation of this substance confirmed 

 Pelouze's view of the composition of gun-cotton. 



It was believed by some chemists at about this period that pyroxylin was itself only 

 slightly soluble in mixtures of alcohol and ether, but that these mixed solvents either- 

 modified its character, or separated it into two distinct explosive bodies, the one being 

 soluble, and the other insoluble in the ether and alcohol. Others regarded the differ-, 

 ence in solubility exhibited by gun-cotton, according to the manner in which it had 

 been prepared, as ascribable to differences of molecular condition and not of com- 

 position. 



But all the early investigators of this subject appear to have agreed in the opinion 

 that the action of nitric acid, or the mixed acids, was completed in a few minutes, and 

 that, however much the treatment with acids was protracted, no further change was 

 effected. 



Gerhakdt, in his 'Traite de Chimie Organique' (1854), states that, as no gas is dis- 

 engaged in the production of pyroxylin (a point upon which Pelouze lay^ stress in his 

 earlier papers), this substance may be affirmed to contain the elements of cellulose plus 

 two or three proportions of the elements of nitric anhydride, and that it may be repre^ 

 sented as cellulose in which two or three atoms of hydrogen are replaced by their equi- 

 valent of peroxide of nitrogen. This view of the composition of gun-cotton, which was 

 first enunciated by Ckum, received very strong support from the interesting researches 

 of Hadow, published in 1854. The experiments of this chemist furnished conclusive 



2p2 



