ME. ABEL'S EESEAECHES ON GUN-COTTON. 273 



tion (in 1864) of the memoir of PfiLOUZE and Maury, in which that view is combated, 

 and a new formula, 



C^ H,8 0,8, 5N O, (C24 H,6 0.8, 5N2 O5), 



is assigned to that substance, which differs, by the elements of one equivalent of water, 

 from P£louze's second formula, adopted in 1847. 



Some analytical results are referred to by PfiLOUZE and Maury in support of their view 

 of the composition of gun-cotton ; but they base their new formula principally upon the 

 increase of weight which they have found cotton to sustain by treatment with the 

 mixed acids, and which they now fix at 78 per cent, (the numbers formerly arrived at 

 by PjfiLOUZE being from 68 to 70 and from 74 to 76 percent.). The theoretical increase 

 of weight Avhich pure cellulose should sustain upon complete conversion into a substance 

 of the composition assigned to it by PfiLOUZE and Maury is 77*78 per cent. ; while, if 

 gun-cotton were completely converted into trinitro-ceUulose, it should gain in weight 

 83-3 per cent. 



It would appear that these numbers are sufficiently far apart to preclude any uncer- 

 tainty with regard to the correctness of a conclusion in favour of either formula, if 

 based upon careful and sufficient experiments. Nevertheless, P£louze and Maury state, 

 on the one hand, that they base their somewhat complex formula upon the results of 

 many experiments, variously instituted ; while, on the other hand, the results arrived at 

 by Hadow, which are not in any way referred to by P^louze and Maury, and have never 

 yet been called into question, appear to furnish very strong evidence in favour of the 

 more simple formula. 



Early in 1863, by desire of the Secretary of State for War, I entered upon a detailed 

 investigation of the manufacture of gun-cotton, the composition of the material when 

 produced upon an extensive scale, its behaviour under circumstances favourable to its 

 change, and other subjects relating to the chemical history of this remarkable body. 



The continuation of these investigations was afterwards entrusted to me by my col- 

 leagues, upon the appointment of a Government Committee on Gun-cotton. 



The circumstance that the manufacture of the supplies required for artillery- and other 

 experiments has been carried on under my direction, has enabled me to institute nume- 

 rous experiments upon a considerable scale, in some of which the conditions of 

 manufacture have been varied, while in others the quantity of product furnished has 

 been carefully determined. By combining such experiments with a very extensive series 

 of analytical and synthetical laboratory investigations, I have endeavoured to render 

 both rigorous and exhaustive the examination into the uniformity of the process of 

 manufacture of gun-cotton as perfected by Von Lenk, and into the composition of the 

 product. 



I.— MANUFACTURE OF GUN-COTTON. 



The system of manufacture of gun-cotton which is the result of Von Lenk's perse- 

 vering endeavours to perfect this material, does not, at first sight, present any important 



