ADDRESS. 31 
of potassium and barium, and converted into grains through the agency 
of a solvent and a binding material. Both these powders produce very 
little smoke compared with black powder, but they do not compete with 
the latter in regard to accuracy of shooting, when used in military arms. 
In past years both camphor and liquid solvents have been applied to the 
_ hardening of the surfaces of granulated or compressed masses of gun-cotton 
and of this classofits preparations, with a view to render them non-porous. 
In some smokeless powders of French, German, Belgian, and English 
manufacture, acetic ether and acetone have been also used, not merely to 
harden the granules or tablets of the explosive, but also to convert the 
nitre-cellulose, in the first instance, into a more or less gelatinous con- 
dition, so that it can readily be incorporated with other components and 
rolled, or spread into sheets, or pressed into moulds, or squirted into 
wires, rods, or tubes, while still in a plastic state. When the solvent 
has afterwards been removed, the hardened, horn-like, or somewhat 
plastic product is cut up into tablets, or into strips or pieces of suitable 
dimensions, for conversion into charges or cartridges. 
Another class of smokeless powder, similar in physical characteristics 
to these nitro-cellulose powders, but containing nitro-glycerine as an im- 
portant component, has been originated by Mr. Aifred Nobel, the well- 
known inventor of dynamite, and bears resemblance in its physical charac- 
teristics to another of his inventions, called blasting-gelatine, one of the 
most interesting of known violent explosive agents. When one of the 
lower products of nitration of cellulose is impregnated with the liquid 
explosive, nitro-glycerine, it gradually loses its fibrous nature, becoming 
gelatinised while assimilating the liquid; and the resulting product 
almost possesses the characters of a compound. This preparation, and 
certain modifications of it, have acquired high importance as blasting- 
agents more powerful than dynamite, and are possessed of the valuable 
‘property that their prolonged immersion in water does not separate 
from them any appreciable proportion of nitro-glycerine. The nitro- 
glycerine powder first produced by Mr. Nobel was almost perfectly 
smokeless, and developed very high energy, accompanied by moderate 
pressures at the seat of the charge; but it possessed certain practical 
defects, which led to the development of several modifications of that 
explosive and various improvements in manufacture. The relative 
Merits of this class of smokeless powder, and of various kinds of 
nitro-cellulose powder, are now under careful investigation in this and 
other countries, and several more or less formidable difficulties have been 
et with in their application, in small-arms especially ; these arise in part 
from the comparatively great heat they develop, whick increases the 
erosive effects of the products of explosion, and in part from the more 
or less complete absence of solid products. The surfaces of the barrel 
and of the projectile being left clean, after the firing, are in a con- 
dition favourable to their close adhesion while the bullet is propelled 
