1864. | Russert on Gun-cotton. 405 
acid and cotton fibre which forms tri-nitro-cellulose, the chemical 
name of gun-cotton. Chemistry must also tell us how tri-nitro- 
cellulose is to be turned by heat into transparent explosive gases of 
such tremendous power. 
In short, chemistry has to supply us with the new material, and it 
is to the science of mechanics that we must look for inventions, of the 
best way to manipulate and apply it to use for doing the practical 
work we set it to, in the most effectual, convenient, and economical 
way. 
The chemistry of gun-cotton is therefore the first part of our 
study of this power, and the mechanics of gun-cotton forms the 
second. 
I.—Tue Cuemistry or Gun-Corron.* 
Although gun-cotton was discovered eighteen years ago by one of 
the first chemists of the day, Professor Schonbein, and researches on 
its nature and preparation were almost immediately instituted in this 
country by Porrett, Teschemacher, Taylor, Gladstone and others, no 
accurate knowledge of the true constitution and chemical nature of 
this important material was obtained until Hadow, an English chemist, 
published in 1854 the result of some valuable investigations by which 
the mode of formation and composition of gun-cotton were conclusively 
established. 
Cotton, or cellulose as it is termed by chemists, is built up of a 
certain number of atoms of carbon, oxygen, and hydrogen. Chemistry 
is scarcely yet able to point out how these atoms are probably 
arranged ; but there appears to be no doubt that some of the elemen- 
tary particles are so intimately connected with the very existence 
of cotton, that they cannot be displaced or removed without destroy- 
ing the very existence of the substance ; whilst other atoms, on the 
contrary, are more loosely held together, and are gifted with a certain 
mobility which enables them to be taken out altogether without 
materially altering the outward physical character of the cotton, 
provided the spaces which these atoms would leave vacant, are 
immediately filled up by certain other atoms. Now, without entering 
into the details of chemical formule, which would neither interest our 
readers nor render our meaning more intelligible, we may briefly say 
that, in ordinary cotton, three atoms of the hydrogen (of which there 
are ten altogether) are in this loose state of combination, and may be 
removed and their places filled up by a compound atom of hyponitric 
acid without so far altering the character of the substance as to ren- 
der the name of cotton inapplicable to it. It may be just mentioned 
in passing, that it is not necessary that the whole three atoms of 
hydrogen should be taken out and their places filled up by hyponitric 
acid ; only one or two of them may be so replaced, but as these are 
inferior for explosive purposes (although of great use to photographers, 
inasmuch as when dissolved in ether they form collodion), we need 
* For this portion of my paper I am indebted to the kindness of Mr. Wm. 
Crookes, F.R.S. 
