MODERN GUNPOWDER AND CORDITE. 
283 
where it is kept in sufficient quantities for use in the manufacture of 
cordite. When finished, the nitro-glycerine is subjected to the “ heat 
test/' similarly to gun-cotton, audit should stand the test at 160° Fahr. 
for 15 minutes. 
As cordite is composed of two “ high explosives/' gun-cotton and 
nitro-glycerine, the means adopted for converting them into a reliable 
propellant have now to be considered. 
“ High explosives" have all, more or less, the characteristics to 
which they owe their title. These are, great sensitiveness under certain 
conditions, and liability to violent explosiveness or detonation in their 
ordinary or “ untamed" condition. This is exhibited in a graphic 
form in the diagram (Fig. 2). 
One can well understand that none of these substances untamed are 
suitable for use with arms of precision. Under certain circumstances 
they might give fair shooting and satisfactory results; and under 
others their violence might be productive of the most serious conse¬ 
quences. A reliable retarding or £s taming" agent was therefore 
absolutely necessary, and by using a solvent, such as acetone, and 
reducing gun-cotton to a plastic mass and then adding an inert or 
u slowing " substance, either a resin, grease, or other material, this 
violent explosive has been tamed down to any degree of rapidity of 
combustion required. 
Gun-cotton has, however, one serious drawback, and that is that 
even with the highest degree of explosiveness which can be permitted 
for safety, it does not produce a satisfactory proportion of permanent 
gases during combustion, and the pressures developed are too high in 
comparison for the velocities obtained with the projectiles. We are 
therefore obliged to introduce some other ingredient which, while not 
producing smoke, will evolve the necessary gases for propulsion of the 
projectile, without increasing the rapidity of combustion or involving 
the risk of detonation. All manner of inert substances have been tried 
for this purpose with more or less success, but none as yet have been 
perfectly satisfactory. I may say, however, that a near approach to a 
gun-cotton smokeless powder was made at Waltham Abbey some years 
ago, when a grained powder was produced which, while smokeless, gave 
the best shooting obtained up to that time. Just at this period, how¬ 
ever, the discoveries previously referred to were developed, namely, 
that an active agent could be used with gun-cotton, and nitro-glycerine 
combinations rapidly took the field. 
The strange anomaly of two of the most violent explosives known, 
nitro-glycerine and gun-cotton, when combined in nearly equal propor¬ 
tions, producing a moderate explosive under control was, as I have 
already said, the starting point of a new era in smokeless powders. 
Nitro-glycerine is, as we know, about the most violent explosive yet dis¬ 
covered, gun-cotton is also noted in the list of “ high explosives." Both 
when separate are very sensitive and easily detonated; but when com¬ 
bined they burn with great regularity. 
I have now briefly mentioned the two great classes of smokeless 
powders; first gun-cotton and its kindred chemical compositions with 
a retarding agent, and, second, gun-cotton combined with nitro-glycerine 
