ON THE APPLICATION OF GUN*-COTTON TO WARLIKE PURPOSES, 3 
1st, The cleansing and perfect desiccation of the cotton, as a preliminary 
to its immersion in the acids. 
2nd, The employment of the strongest acids attainable in commerce. 
3rd, The steeping of the cotton in a fresh strong mixture of acids, after 
its first immersion and partial conversion into gun-cotton. 
4th, The continuance of the steeping for forty-eight hours. 
5th. The thorough purification of the gun-cotton so produced, from every 
trace of free acid. This is secured by its being washed in a stream of water 
for several weeks. Subsequently a weak solution of potash may be used, but 
this is not essential. 
The prolonged continuance of these processes appears at first sight super- 
fluous, but it is really essential ; for each cotton-fibre is a long narrow tube, 
often twisted and even doubled up, and the acid has first to penetrate into the 
very furthest depths of these tubes, and afterwards has to be soaked out of 
them. Hence the necessity of time. It seems to have been mainly from 
want of these precautions that the gun-cotton experimented on by the French 
Commission gave irregular and unsatisfactory results. (C. 1.) 
From the evidence before the Committee, it appears that this highest 
nitro-compound, when thoroughly free from acid, is not liable to some of the 
objections which have been urged against that mixture of compounds which 
has been usually employed for experiments on gun-cotton. 
These advantages may be classed as follows :— 
1st. It is of uniform composition, and thus the force of the gases generated 
on explosion may be accurately estimated. (C. 2.) 
2nd. It will not ignite till raised to a temperature of at least 136° C. 
(277° F.), a heat which does not occur unless artificially produced by means 
which would render gunpowder itself liable to ignition. (C. 5.) 
3rd. It is almost absolutely free from ash when exploded in a confined 
space. 
4th, It has a very marked superiority in stability over other forms of gun- 
cotton, It has been kept unaltered for fifteen years, and is not liable to 
that spontaneous slow decomposition which is known to render lower products 
worthless after a short time. (C. 4,6.) Yet there are still some reasons for 
suspecting that even the gun-cotton produced at the Imperial works suffers 
some gradual deterioration, especially when exposed to the sunlight. (A. 20, 
C. 3.) 
The details of the process of manufacture at Hirtenberg are given at length 
in Mr. Abel’s first report, in General von Lenk’s replies (L. 21), and in a 
patent (No, 1090) taken out by Mr. Thomas Wood Gray, and sealed Oct. 10, 
1862. 
The course of proceeding recently adopted at the Royal Gunpowder 
Works, Waltham Abbey, is fully described in Mr, Abel’s third memorandum. 
A. 10-16.) 
: There is one part of the process not yet alluded to, and the value of which 
is more open to doubt, namely, the treatment of the gun-cotton with a solu- 
tion of silicate of potash, commonly called water-glass. Mr. Abel (A. 15) 
and the Austrian chemists think lightly of it; but Baron Lenk considers 
that the amount of silica set free on the cotton by the carbonic acid of the 
atmosphere is really of service in retarding the combustion. He adds that 
some of the gun-cotton made at the Austrian Imperial Works has not been 
silicated at all, and some but imperfectly; but when the process has been 
thoroughly performed, he finds that the gun-cotton has increased permanently 
about 3 per cent. in weight. A piece of one of the samples left by the 
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