gun-cotton colloid, without any nitro-glycerine, that is, gun-cotton
dissolved and dried, would burn more slowly, keep better, and give
better ballistics than it would if combined with nitro-glycerine. It was
also thought that gun-cotton of a high degree of nitration when made
into colloidal form would even then burn too quickly to be suitable for
use in firearms. Consequently, the first experiments were with low grade
gun-cotton, what is called collodion cotton, such as is employed in the
manufacture of celluloid. But, as this would not explode without the
addition of some oxygen-bearing element, various oxygen-bearing salts
were combined with it, such as nitrate of potassium, nitrate of ammonia,
nitrate of baryta, etc. Also a great many of the first smokeless powders
were made of low grade gun-cotton combined with nitro-glycerine in
varying proportions. These powders would often give very good results
when first made; but low grade gun-cotton or di-nitro-cellulose, as it
is called, is a very unstable compound, and these powders, after giving
very promising results, were found to be constantly undergoing change,
sooner or later resulting in complete decomposition.

When nitro-glycerine was first combined with gun-cotton in small
quantities, camphor was often added, to lessen the rapidity of
combustion which the nitro-glycerine was supposed to impart and also to
render the compound more plastic, and to tend to prevent the
decomposition of the low grade gun-cotton. But camphor being volatile,
would, by its evaporation, cause the powder to constantly change in
character. Castor oil has been found to be a better diluent, as this
will not evaporate.

As all of the smokeless powders made of a low grade gun-cotton were
found to deteriorate and spoil, experiments were made with gun-cotton of
the highest degree of nitration, both alone and in combination with