286 



lOl. ABEL'S EE8EAECHE8 ON GUN-COTTON. 



The proportions of matter soluble in alcohol alone, and in the ethereal mixture, were 

 successively determined in a few samples of gun-cotton, and furnished the following 

 results : — 



Description of giin- cotton. 



Waltham Abbey, 1863 

 1864 



Stowmarket 



exceptional 



Alcoholic 



extract. 

 Per cent. 



0-75 

 . 0-72 

 0-95 

 0-90 

 0-78 

 0-95 



Ethereal 

 extract. 

 Per cent. 



1-31 

 1-35 

 1-48 

 1-42 

 1-18 

 11-78 



Total soluble 

 matter. 



2-06 

 2-07 

 2-43 

 2-32 

 2-96 

 12-73 



Result obtained by 



direct extraction ■with 



ether and alcohol. 



Per cent. 



1-91 

 1-93 

 2-21 

 2-60 

 3-00 

 12-55 



The foregoing results show that, in the general products of manufacture obtained by 

 properly following Von Lenk's instructions with regard to the conversion of the cotton, 

 the proportion extracted by alcohol alone is somewhat below 1 per cent., and consists 

 of nitrogenized matter, of acid character, which has evidently been produced by the action 

 of nitric acid upon the resinous or other foreign substances contained in the cotton at the 

 time of its conversion. The portion soluble in ether and alcohol, but insoluble in spirit, 

 varies in amount between 1 and 2 per cent., and consists of the very small proportion 

 of gun-cotton which has escaped conversion into the most explosive product. The 

 occurrence, in a few quite exceptional instances, of comparatively large proportions of 

 soluble gun-cotton, of the kind produced by the action of a warm somewhat dilute acid 

 mixture upon cotton, aifords important evidence of the necessity for adhering strictly to 

 the mode of treatment, and the precautions, which considerable experience and a careful 

 examination of products have proved to be indispensable to the attainment of uniform 

 results in the manufacture of gun-cotton. 



With regard to the matter soluble in ether and alcohol found to exist in gun-cotton, 

 the following observations possess some interest, as bearing upon the cause of its pro- 

 duction in the manufacture of the substance. 



1. The mean proportion of soluble matter furnished by the very concordant results 

 of examination of gun-cotton manufactured at Waltham Abbey in 1863, in the prepa- 

 ration of which the acids, left in contact with the gun-cotton, were in the proportion of 

 18 parts by weight to 1 of cotton, is 1-62 per cent. ; while the mean proportion furnished 

 by the results of examination of sixteen samples of Waltham Abbey products, in the 

 manufacture of which only 10 parts of the acids were left in contact with the gun-cotton, 

 is 2-13 per cent. All the results obtained with the first gun-cotton were below 2 per 

 cent., while out of sixteen results, obtained with the last, eleven were above 2 per cent. 

 Here we have a decided indication that the prolonged contact with acid has some 

 inlluence upon the composition of the product ; the employment of the higher proportion 

 of acid furnished results more nearly approaching perfection than those when the gun- 

 cotton was left in contact with a smaller proportion of the acid mixture. As far as can 



