184 
MR. ABEL’S RESEARCHES ON GUN-COTTON. 
Bouchet in 1847, which had undergone alterations such as have already been described. 
These were examined for sulphuric acid, and none was detected ; hence the conclusion is 
drawn that these samples had been perfectly washed, and that their spontaneous change 
could not be ascribed to imperfect purification. It is argued that instances of change 
have been observed to occur under ordinary atmospheric conditions, similar to those 
established in gun-cotton at higher temperatures ; that, because exposure to the latter 
had occasionally brought about spontaneous explosion, it is possible for instances of 
spontaneous decomposition at ordinary temperatures to result in explosions, and that, 
consequently, it is right to conclude that the storage of large quantities of gun-cotton 
is attended by great risk of explosion. In further support of this conclusion the obser- 
vations are recorded, that the most perfectly washed gun-cotton becomes acid by long 
exposure to sunlight ; that some pyroxylin, which was alkaline at first, after exposure 
for several weeks to light, in contact with the sides of a glass flask, exhibited an acid 
reaction ; and that, even when gun-cotton is preserved in the dark, this acidity invariably 
becomes manifest in course of time. Finally, without referring to any single instance in 
which an explosion or even an appreciable development of heat has been observed as 
resulting from protracted exposure of gun-cotton to strong daylight or sunlight, Pelouze 
and Maury conclude that the indications of gradual decomposition furnished by certain 
specimens of gun-cotton under those conditions, are sufficient proof of the liability of 
this material, as now manufactured, to explode spontaneously, when stored in considerable 
quantities. 
The researches into the manufacture, composition, and properties of gun-cotton, upon 
which, as a member of the Government Gun-cotton Committee, I have been engaged 
for nearly four years, have included, from their very commencement, careful observa- 
tions and a great variety of experiments, with both small and large quantities of mate- 
rial, bearing upon the influence exerted by light and heat, and by various modifications 
introduced into the system of manufacture, upon the stability of gun-cotton produced 
in accordance with the general directions laid down by Yon Lenk. It is obvious that, 
although most of these experiments have furnished very decisive results within a com- 
paratively brief period, there are others which become the more valuable and the more 
fully conclusive in their character, the longer the period of their duration. It is con- 
sidered, however, that the data which even the latter class of experiments has already 
furnished possess sufficient scientific interest and practical importance to warrant their 
present publication, in addition to those obtained by numerous experiments instituted 
with the view to ascertain whether and to what extent the results of researches recently 
published in France upon the spontaneous changes of gun-cotton, apply to the material 
manufactured in this country during the last four years. 
The experiments and observations carried on at Woolwich may be classed as having 
for their objects, — 
(a) The determination of the influence of light and of long protracted storage, under 
ordinary conditions as to temperature, upon the stability of gun-cotton ; 
