nitro-glycerine. These experiments were first conducted in England by
private parties and by the British government, when it was found that
high grade gun-cotton would give excellent results if made into a
colloidal solid and used alone, or in combination with certain other
constituents. With a view to saving the large quantity of solvents
necessary to reduce the gun-cotton, and to get a more prompt and certain
ignition with a larger grain, experiments were cautiously made by the
admixture of varying proportions of nitro-glycerine to the gun-cotton
when dissolved, or rather along with other solvents in the process of
dissolving it.

It was soon found that nitro-glycerine added in quantities, even equal
in weight to the gun-cotton itself, did not materially increase the
rapidity of the explosion of the compound. And it was also found that
high grade gun-cotton, when combined with nitro-glycerine, gave very
much better results than low grade gun-cotton.

I have spoken here of high and low grade gun-cotton, when in fact the
word gun-cotton should be applied only to the highest nitro-compound of
cellulose. The word gun cotton has always been rather loosely used.
Pyroxyline would be a better word, as this applies to all grades. When
cotton fiber is soaked in a large excess of a mixture of the strongest
nitric and sulphuric acids, gun-cotton proper, or that of the highest
grade, is produced. When weaker acids are used, lower grades of
nitro-cellulose are formed.

The first mentioned or highest grade gun-cotton, when thoroughly freed
from its acids, has always proved to be a perfectly stable compound. The
lower grades have always been found to be unstable and subject to
spontaneous decomposition. Nitro-glycerine has also been erroneously