ME. ABEL’S RESEARCHES ON GUN-COTTON. 
211 
1865, the ordinary process of manufacture having been strictly followed, with the ex- 
ception of the necessary difference in the strength of the acid-mixture used. This gun- 
cotton was found to correspond closely in composition to the formula of Hadow’s com- 
pound “ C” (G 18 H 23 0 15 7N0 2 ), as shown in my first Memoir*. It has exhibited no 
tendency whatever to change by long-continued exposure to diffused daylight ; several 
comparative experiments have been instituted with it and with samples of ordinary 
Waltham- Abbey products, and it has never exhibited any indications of greater suscepti- 
bility to change than the most stable of these. Indeed, the following results would 
appear to indicate that any difference in stability which may exist between the different 
members of the nitrocellulose group is not in the direction assumed by Redtenbacher,, 
Schrotter, and Schneider. 
Experiment 94. — A portion (about 1 grm.) of the soluble gun-cotton, which had been 
reduced to a fine state of division in a pulping-machine, was introduced into a wide-bulb 
tube, and a similar tube was charged with a corresponding quantity of ordinary gun- 
cotton in the same mechanical condition. Both specimens were air-dry. They were 
exposed in the same water-bath seven hours daily to 100° C. Not the slightest indica- 
tion of change was observed in either specimen until towards the close of the seventh 
day, when a faint coloration by nitrous acid was observed on looking down the tube 
containing the ordinary gun-cotton. Very shortly afterwards a still fainter coloration 
was noticed in the tube containing the finely-divided soluble gun-cotton. Both samples 
continued from this time to undergo slow decomposition ; but for several hours after 
the first commencement of change, the ordinary gun-cotton evolved nitrous vapours 
more abundantly than the soluble sample. 
Experiment 95. — Larger quantities (11 grms. and 33 grms.) of ordinary gun-cotton and 
of the soluble gun-cotton, both in a fine state of division, were exposed day and night 
uninterruptedly to 60° C. After a period of one month the soluble gun-cotton had sus- 
tained not the slightest loss of weight, the ordinary gun-cotton having lost (M)58 per 
cent. At the expiration of another month’s uninterrupted heating, the weight of the 
soluble gun-cotton was still found to have sustained no change, while the ordinary gun- 
cotton had only sustained a further loss of 0*02 per cent.f 
These and other similar results appear to demonstrate satisfactorily that the lower 
nitrocellulose compounds, when prepared in a condition of equal purity with the ordi- 
nary gun-cotton, are certainly not more prone to change at high temperatures. 
EXPOSURE OF GUN-COTTON TO 90° C. 
It is stated by Pelouze and Maury that in their experiments the exposure of gun- 
cotton to 90° furnished identically the same results as those produced by the tempera- 
• * Philosophical Transactions, vol. clvi. p. 297. . 
t After continuous exposure of these samples at 60°, for a further period of four months, the soluble gun- 
cotton is found not to have sustained any loss in weight, while the total loss sustained by the ordinary gun- 
cotton amounts to 0-19 per cent. — June 8th, 1867. 
