442 



NATURE 



[September 4, 1890 



smokelessness of the latter. Whilst the products of explosion 

 of the nitro-compounds consist exclusively of gases and of 

 water-vapour, gunpowder, being composed of a large pro- 

 portion of saltpetre, or other metallic nitrate, mixed with 

 charred vegetable matter and variable quantities of sulphur, 

 furnishes products of which over 50 per cent, are not gaseous, 

 even at high temperatures, and which are in part deposited as a 

 fused solid — which constitutes the fouling in a firearm — and in 

 part distributed in an extremely fine state of division through 

 the gases and vapours developed by the explosion, thus giving 

 to these the appearance of smoke as they escape into the air. 



So far as smokelessness is concerned, no material can surpass 

 gun-cotton (or other varieties of nitro-cellulose) ; but, even if the 

 rate of combustion of the fibrous explosive in a firearm could be 

 controlled with certainty and uniformity, its application as a safe 

 propulsive agent is attended by so many difficulties that the 

 non-success of the numerous early attempts to apply it to that 

 purpose is not surprising. Those attempts, commencing soon 

 after the discovery of gun-cotton, in 1846, and continued many 

 years later in Austria, consisted entirely in varying the density 

 and mechanical condition of employment of the gun-cotton 

 fibre. No difficulty was experienced in thus exercising complete 

 control over the rapidity of burning in the open air ; but when 

 the material was strongly confined, as in the bore of a gun, such 

 methods of regulating its explosive force were quite unreliable, 

 as some slight unforeseen variation in its compactness or in the 

 amount and disposition of the air-spaces in the mass, would 

 develop very violent action. Much more promising results were 

 subsequently obtained by me by reducing the fibre to a pulp, as 

 in the ordinary process of making paper, and converting this 

 into highly-compressed, homogeneous masses of the desired form 

 and size. Some favourable results were obtained at Woolwich, 

 in 1867-68, in field-guns, with cartridges built up of compressed 

 gun-cotton variously formed and arranged, with the object of 

 regulating the rapidity of explosion of the charge. But although 

 comparatively small charges often gave high velocities of pro- 

 jection, without any indications of injury to the gun, the uniform 

 fulfilment of the conditions essential to safety proved to be 

 beyond absolute control, even in guns of small calibre ; and 

 military authorities not being, in those days, alive to the 

 advantages which might accrue from the employment of an 

 entirely smokeless explosive in artillery, experiments in this 

 direction were not persevered in. At the same time, consider- 

 able success attended the production of gun-cotton cartridges for 

 sporting purposes, the rapidity of its explosion being controlled 

 by various methods ; very promising results were also attained with 

 the Martini-Henry rifle and a lightly-compressed pulped gun- 

 cotton charge, of pellet-form, the uniform action of which was 

 secured by simple means. 



A nearly smokeless sporting-powder had, in the meantime, 

 been produced by Colonel Schultze, of the Prussian Artillery, 

 from finely-divided wood, converted after purification into a 

 mildly explosive form of nitro-cellulose, and impregnated with 

 a small portion of an oxidizing agent. Subsequently this powder 

 was produced in a granular form, and rendered considerably 

 more uniform in character, and less hygroscopic ; it then closely 

 resembled the well-known E.G. sporting-powder, which consists 

 of a nitro-cotton reduced to pulp, incorporated with the nitrates 

 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 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 com- 

 pressed masses of gun-cotton and of this class of its 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 

 nitro-cellulose, in the first instance, into a more or less gelatinous 

 condition, 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 ot suitable dimensions, for 

 conversation into charges or cartridges. 



Another class of smokeless powder, similar in physical charac- 

 teristics to these nitro-cellulose powders, but containing nitro- 



i\0. T088, VOL. 42] 



glycerine as an important component, has been originated by 

 Mr. Alfred Nobel, the well-known inventor of dynamite, and 

 bears resemblance in its physical characteristics to another of 

 his inventions, called blasting-gelatine, one of the most interest- 

 ing 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 gelatinized 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 

 rtlative merits of this class of smokeless powder, and of various 

 kinds of nitro-cellulose powder, are now under careful investiga- 

 tion in this and other countries, and several more or less 

 formidable difficulties have been met with in their application, 

 in small-arms especially ; these arise in part from the compara- 

 tively great heat they develop, which 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 

 condition favourable to their close adhesion while the bullet is 

 propelled along the bore, with the consequent establishment of 

 very greatly increased friction. The latter difficulty has been 

 surmounted by more than one expedient, but always at the cost 

 of absolute smokelessness. 



Our knowledge of the results obtained in France and Germany 

 with the use of smokeless powders in the new rifles and in artillery 

 is somewhat limited ; our own experiments have demonstrated 

 that satisfactory results are attainable with more than one variety 

 of them, not only in the new repeating-arm of our infantry, but 

 also with our machine-guns, with field-artillery, and with the 

 quick-firing guns of larger calibre which constitute an important 

 feature in the armament of our Navy. The importance of ensur- 

 ing that the powder shall not be liable to undergo chemical 

 change detrimental to its efficiency or safety, when stored in 

 different localities where it may be subject to considerable 

 variations of temperature (a condition especially essential in 

 connection with our own naval and military service in all parts 

 of the world), necessitates qualities not very easily secured in an 

 explosive agent consisting mainly of the comparatively sensitive 

 nitro-compounds to which the chemist is limited in the production 

 of a smokeless powder. It is possible, therefore, that the extent 

 of use of such a material in our ships, or in our tropical posses 

 sions, may have to be limited by the practicability of fulfilling 

 certain special conditions essential to its storage without danger 

 or possible deterioration. If, however, great advantages are 

 likely to attend the employment of a smokeless explosive, at any 

 rate for certain Services, it will be well worth while to adopt 

 such special arrangements as may be required for securing these 

 without incurring special dangers ; this may prove to be especially 

 necessary in our ships of war, where temperatures so high as to 

 be prejudicial even to ordinary black powder, sometimes prevail 

 in the magazines, consequent mainly upon the positions assigned 

 to them in the ships, but which may be guarded against by. 

 measures not difficult of application. 



The Press accounts of the wonderful performances of the first 

 smokeless powder adopted by the French — which, it should be 

 added, were in some respects confirmed by official reports of 

 officers who had witnessed experiments at a considerable distance 

 — engendered a belief that a very great revolution in the conduct 

 of campaigns must result from the introduction of such powders. 

 It was even reported very positively that noiselessness was one 

 of the important attributes of a smokeless powder, and highly- 

 coloured comparisons have, in consequence, been drawn in 

 Service-periodicals, and even by some military authorities, 

 between the battles of the past and those of the future ; the 

 terrific din caused by the firing of the many guns and the roar of 

 infantry-fire, in heavy engagements, being supposed to be re- 

 duced to noise so slight that distant troops would fail to know in 

 what direction their comrades were engaged, and that sentries 

 and outposts would no longer be able to warn their comrades of 

 the approaching foe by the discharge of their rifles. Military 



