ME. ABEL’S EESEAECHES ON GUN-COTTON. 
219 
dance. The gun-cotton was washed and twice treated in the same manner, the alkali 
being neutralized on each occasion, as in the first instance. 
But though it is evident that the treatment of gun-cotton with warm alkaline baths 
cannot be advantageously extended, satisfactory proof has been obtained that the stability 
of gun-cotton which has been purified as far as is possible by the present system, may 
be importantly increased by submitting the material to a special process of washing. 
In the experiments instituted upon the application of gun-cotton as a substitute for 
gunpowder, some very advantageous results have attended the conversion of the material 
into homogeneous masses of any desirable form or density, by preparing it according to 
the method commonly employed for converting rags into paper. In reducing the mate- 
rial to a very fine state of division by means of the ordinary beating- and pulping-machines, 
the capillary power of the fibres is nearly destroyed, and the gun-cotton is, for a consider- 
able period, very violently agitated in a large volume of water. It would be very difficult 
to devise a more perfect cleansing process than that to which the gun-cotton is thus sub- 
mitted ; and the natural result of its application is that the material thus additionally 
purified acquires considerably increased powers of resisting the destructive effects of heat. 
Samples of the pulped gun-cotton even in the most porous condition have been found 
to resist change perfectly upon long-continued exposure to temperatures which deve- 
loped marked symptoms of decomposition in the gun-cotton purified only as usual (expe- 
riments 94 and 95 may be referred to in illustration of this). 
The pulping process applied to gun-cotton affords therefore important additional 
means of purifying the material, the value of which may be further enhanced by em- 
ploying a slightly alkaline water in the pulping-machine. 
II. Impregnation of gun-cotton with substances capable of neutralizing free acid. — The 
slightest change sustained by gun-cotton is attended by the development of free acid, 
which, if it accumulates in the material, even to a very trifling extent, greatly promotes 
decomposition. Numerous experimental data have been collected with respect to the 
establishment and acceleration of decomposition in gun-cotton exposed to light or elevated 
temperature by free acid, which either is present in the imperfectly purified material, or 
has been developed by decomposition of gun-cotton or its organic impurities. 
Experiment 116. — Samples of gun-cotton which, by exposure to elevated temperatures 
or for considerable periods to strong daylight, had sustained changes resulting in a con- 
siderable development of acid, have afterwards been thoroughly purified by washing and 
exposed to light for months, and in some instances for two and three years (up to the 
present time) without undergoing further change, while corresponding samples, confined 
m closed vessels without being purified, have continued, in some instances, to undergo 
decomposition, and the original substance has been completely transformed into the 
products repeatedly spoken of. Instances have, however, occurred in these experiments 
(and have already been quoted) in which gun-cotton has resisted further change, even 
under these circumstances. 
