MR. .ABEL’S RESEARCHES ON GUN-COTTON. 
difficulties in the manufacture of pure gun-cotton which further experimental research 
may overcome ; but that, in the mean time, these objections are entirely set aside by 
the adoption of two very simple measures, against the employment of which no practical 
difficulties can be raised, and which there is every reason to believe must secure for 
this material the confidence of those who desire to avail themselves of the special 
advantages which it presents as an explosive agent. 
The nature of the decomposition of gun-cotton, when exploded under different con- 
ditions, is now under investigation by me, and the results arrived at will I trust be com- 
municated before long to the Royal Society. 
Note. — Since this Memoir was communicated to the Royal Society, a circumstance 
of a very unexpected nature has been observed, accidentally in the first instance, which 
appears to have an important bearing upon the question of the stability of gun-cotton. 
A skein of Waltham Abbey gun-cotton has been suspended upon a line in the upper 
part of my laboratory for about twelve months. It has therefore been freely exposed 
to air and diffused daylight during that period. A portion of this sample was recently 
employed in a comparative heat-experiment, with some specially prepared samples, and 
was found to resist exposure to 100° C. in a very remarkable manner. Several portions 
have been maintained for many hours at 100°, upon consecutive days, without under- 
going the slightest change, although originally a brief exposure to that temperature 
sufficed to develope symptoms of decomposition in this gun-cotton. 
The behaviour of this specimen led to an examination of several samples of Stow- 
market gun-cotton, portions of which had been employed in the heat-experiments 
described in Table III. of this Memoir, and which have since been exposed to diffused 
daylight, in loosely stoppered bottles, for about 2A years. Three among them which, 
when first examined, were found to undergo decomposition after exposure for a few 
minutes to 100° C., were selected for re-examination, and they all perfectly resisted 
decomposition upon long-continued exposure to that temperature. 
It thus appears definitely established that the stability of gun-cotton is importantly 
increased by long-continued exposure to diffused daylight. An examination into the 
cause of this interesting fact is now being prosecuted, and the results promise import- 
antly to strengthen the confidence which is already placed in the permanence of gun- 
cotton . — June 1867. 
MDCCCLXVII. 
2 M 
