os. REPORT—1863. 
—a conjecture which may receive some support from the fact of the cotton 
being exposed for a very long period to the action of the acids. Under any 
circumstances, this is a matter which may be most intimately connected with 
the question of the keeping qualities of the gun-cotton, and which therefore 
requires the strictest investigation. 
(21) 5. While referring to the question of the stability of gun-cotton, it may 
be important to record the following fact. It is pretty generally known that, 
soon after the discovery of gun-cotton by Schénbein in 1846, Messrs. Hall and 
Son, the extensive gunpowder-manufacturers at Faversham, entered upon the 
manufacture of this material, but were, after a time, so unfortunate as to have 
a very disastrous explosion of gun-cotton at their works, which, after a 
careful inquiry, was ascribed, by the jury and by all connected with the ma- 
nufacture, to the spontaneous combustion of the material. The manufacture 
was stopped on the occurrence of this accident, and a considerable quantity of 
gun-cotton, which existed in the works, was buried by Messrs. Hall’s direction 
(in July 1847), being simply thrown into a hole in the ground and covered 
up with earth. At my request, Messrs. Hall have been so kind as to have a 
sample of this gun-cotton, which has been buried for sixteen years, dug up and 
forwarded to me. This cottdn, after being freed from dirt by washing, pre- 
sented a discoloured appearance, and is stained in many places with oxide of 
iron, but it exhibits not the slightest evidence of haying undergone change. 
The fibre is perfect throughout, and there is, as might have been anticipated, 
no trace of acidity manifest in any portion. It is not a rapidly burning gun- 
cotton, and leaves, upon ignition, a considerable carbonaceous residue ; it does 
not therefore consist, or at any rate not entirely, of the most explosive sub- 
stitution-product. A specimen, purified in the first instance by treatment 
with dilute hydrochloric acid, has been examined synthetically, and yielded 
59-63 per cent. of cotton,—a result which agrees most closely to that which 
would be furnished by a product of the composition C,, { He } O,, (which 
4 
would furnish 60-66 per cent. of cotton). Messrs. Hall manufactured the 
gun-cotton by Schénbein’s original process, which consisted, as far as I can 
learn, in the treatment of the cotton for about one hour with a mixture of one 
part of nitric acid of spec. grav. 1-45 to 1:5, and three parts of sulphuric acid 
of 1:85 spec. grav. The cotton was washed in running water until no acid 
was detected by litmus-paper, and afterwards dipped in a very weak solution 
of carbonate of potassa. The finished cotton was sometimes soaked in a weak 
solution of nitrate of potassa. 
The examination of Messrs. Hall’s buried gun-cotton appears to afford 
an interesting and important proof of the permanence of gun-cotton when 
excluded from air and light, but not protected from moisture—though it is 
necessary to bear in mind that this particular material does not correspond 
in composition to the regular Austrian product. 
(22) 6. Referring once more, in conclusion, to the manufacturing experi- 
ments which form the main subject of this communication, it only remains to 
be stated that the very high price paid for the cotton for these experiments, the 
necessarily temporary arrangements, and the impossibility of fully economi- 
zing labour and material in carrying out the manufacture with such accommo- 
dation as could be furnished without any important outlay at Waltham Abbey, 
rendered the formation of any reliable estimate regarding the cost of the 
gun-cotton out of the question. But the scale upon which the manufacture 
was conducted has been quite sufficient to demonstrate most satisfactorily 
that, with a properly organized system of operation, the production of tne gun- 
