114 
GUN-COTTON. 
tensely heated, old substances are dissolved, their material atoms are redistributed, each 
atom released selects by natural affinity a new partner, these new unions are cemented, 
and at the end of this prolific instant totally new combinations of matter, forming what 
we call new substances, issue from the gun. It so happens that of these new substances, 
formed out of gun-cotton, all are pure transparent gases, while in the case of gunpow¬ 
der there remain 68 per cent, of solid residue, and only 32 per cent, are pure gases. 
It is to chemistry, however, that we must look for full and authentic information as 
to these wonderful changes ; first, from the innocent, gentle cotton-wool in which our 
wives and daughters wrap their jewels for soft keeping, into the terrible and irresistible 
compound of nitric 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. The Chemistry of Gun-Cotton.* 
Although gun-cotton was discovered eighteen years ago by one of the first chemists of 
Ihe 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 im¬ 
portant 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 elementary particles are so intimately connected with the very existence of cotton, 
that they cannot be displaced or removed without destroying 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 formulae, which would neither inter¬ 
est 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 com¬ 
pound atom of hyponitric acid , without so far altering the character of the substance as 
to render 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 only direct our atten¬ 
tion to the compound with the highest displacement. From its explosiveness and con¬ 
sequent similarity to gun -powder, this has been called gun- cotton. In scientific lan¬ 
guage, following the excellent custom adopted by chemists in the nomenclature of or¬ 
ganic compounds, a name has been given to it which fully expresses its composition: 
cellulose being the scientific name for cotton, and the prefix nilro being added when any 
of the hydrogen in an organic compound is replaced by hyponitric acid (by no means an 
uncommon occurrence in organic chemistry), chemists call the product in this instance 
tri-nitro-cellulose , signifying that it is cellulose, in which three equivalents of the hydro¬ 
gen are replaced by nitrous acid. It is also sometimes called pyroxylin , under the im¬ 
pression, we suppose, that by translating a useful English term into barbarous Greek it 
becomes scientific. This system of pseudo-scientific nomenclature is, unfortunately, too 
* For this portion of my paper I am indebted to the kinduess of Mr. Wra, Crookes, F.R.S. 
