Popular Science Monthly/Volume 2/November 1872/Smokeless Gunpowder
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IT is very often the case that one bird falls to the right barrel, and "the rest unhurt" go on their way, rejoicing no doubt at having escaped a deadly volley from the left barrel. There is, however, a reason for their having got off scot-free, well known to all sportsmen; i. e., the smoke from the first barrel obscured the birds from the sportsman's second aim, until they were out of range. Science, however, has discovered a panacea for this oft-recurring disappointment, in Schultze's wood-powder, a smokeless explosive which we wish to introduce to those of our readers who are not already conversant with its merits. Of course, every one knows our "dear, dirty old friend," Black Gunpowder; the acquaintance of which we made in early youth, turning it into a "devil" to frighten our grandmother; but we have cut our "dear, dirty old friend," and our gun is now loaded with Schultze's wood-powder instead. "How is this?" you inquire. "Why abandon an explosive with which Colonel Hawker, and the never-to-be forgotten Maxwell of 'Wild Sports of the West' celebrity, killed so many head of game?" To this we reply, Schultze's wood-powder was not invented in their day, or they would have used it, and for these reasons:
For seven hundred years and more, even granting the invention to have been Roger Bacon's, the dull-black mixture of sulphur, nitre, and charcoal—it is only a mixture, not a chemical compound—has had the monopoly of guns, large and small. It has answered every purpose moderately well, perhaps more than moderately. Nevertheless, from time to time the desire has arisen to evolve out of chemical stores some new compound, mechanical or chemical, that should do better duty. Somewhat extraordinary, indeed, the case seems that, amid all the improvements of guns and gunnery, all the advancement of chemistry and mechanism, the gaseous motor for gun-projectiles should be composed as at first. The explanation is difficult. Gunpowder occupies a sort of half-way ground between things innocent and things dangerous; a medium quality favoring its many applications. Exploding readily enough for all convenient needs, it never spontaneously explodes—a great point in its favor. Then its power of water-absorption not being very great, it stores tolerably well. But, more than any thing else, gunpowder has held its long and almost exclusive sway over guns and gunners owing to the two following circumstances: it can be made of any desired percentage composition, and it may be corned or grained to any degree of coarseness or fineness. As employed for different purposes, it is necessary that gunpowder should have various strengths. To a considerable extent the strength of gunpowder, by varying the relative amount of its components, can be modified; but the great adjustive resource consists in increasing or lessening the dimension of its grains.
Having taken account of certain special good qualities of gun-powder, we now come to certain of its bad qualities. Safe it indeed is in the sense of not igniting spontaneously; but it deteriorates by keeping, the more especially if in a moist atmosphere. If gunpowder be thoroughly wetted, then may it be considered wholly spoilt. In burning, gunpowder evolves much heat, much smoke; it also deposits much foulness. On the debtor side of gunpowder must be reckoned, also, the danger attendant on manufacture. It would be a great advantage if possible to devise a gunpowder that should acquire its usefully-dangerous qualities with the very last manufacturing touch, whereby in every incipient stage it might be stored without possibility of risk.
It will have been gathered, then, that gunpowder, ordinary black gunpowder, though it has seen some service and done some hard duty in its time, is not so perfect as to fulfil all requisitions desired; wherefore from time to time experiments have been directed to the manufacture of a substitute.
The only substitute yet invented which has met with favorable notice from practical sportsmen is Schultze's wood-powder, which, from its being granulated, and consequently permeated by air, can never generate fire of itself. This explosive, invented by Captain Schultze, a Prussian officer, was originally manufactured at Potsdam, near Berlin, and the factory catching fire in 1868, instead of exploding—ruining the neighborhood, and leaving many widows and orphans, like the recent gun-cotton explosion at Stowmarket—burned quietly to the ground. A company of English gentlemen, fond of field-sports, foreseeing the advantages to be derived from its introduction into England, purchased a site for its production in the New Forest, and thither we must carry our readers on "a visit to the Schultze Gunpowder manufactory," at Redbridge near Southampton.
Here and there, at intervals wide apart, are various buildings of light structure, from one of which rises a tall chimney, instrumental in raising steam to drive a 10-horse-power sawing-machine, which rapidly creates the "wood-powder" to be turned into use for the gun by the following process:
The grains, being collected in a mass, are subjected to a treatment of chemical washing, whereby calcareous and various other impurities are separated, leaving hardly any thing behind save pure woody matter, cellulose or lignine. The next operation has for its end the conversion of these cellulose grains into a sort of incipient xyloidine, or gun-cotton material, by digestion with a mixture of sulphuric and nitric acids. Practically it is found that absolutely perfected xyloidine (of which ordinary gun-cotton is the purest type) not only decomposes spontaneously by time, the chief products of combustion being gum and oxalic acid, but it is, moreover, liable to combustion of a sort that may be practically called spontaneous, so slight and so uncontrollable are the causes sufficing to bring it about. Cellulose or woody matter, otherwise termed lignine, partially converted to xyloidine is, the inventor affirms, subject to neither of those contingencies. Our readers will understand that, inasmuch as the wood used as a constituent of the Schultze gunpowder is not charred, its original hydrogen is left, and by-and-by, at the time of firing, will be necessarily utilized toward the gaseous propulsive resultant. Next, washed with carbonate-of-soda solution and dried, an important circumstance is now recognizable.
The grains, brought to the condition just described, are stored away in bulk, not necessarily to be endowed with final explosive energy until the time of package, transport, and consignment. Only one treatment has to be carried out, and it is very simple. The ligneous grains have to be charged with a certain definite percentage of some nitrate, which is done by steeping them in the nitrate solution and drying. Ordinarily a solution of nitrate of potash (common saltpetre) is employed; but, in elaborating certain varieties of white powder, nitrate of baryta is preferred.
Having traced the new powder to its final stage, we may contemplate it under the light of two distinct scrutinies—theoretical and practical. Review of the chemical agencies involved, or that may be evolved, suggests the reaction, especially under prolonged moisture, of the sulphur and nitre of ordinary powder, whereby sulphide of potassium should result. Practice is confirmatory: under the condition indicated sulphide of potassium, more or less, does result, and proportionate to the extent of decomposition is the powder deteriorated. Inasmuch as the Schultze gunpowder is wholly devoid of sulphur, so is the particular decomposition adverted to impossible; and theory, at least, fails to suggest any other decomposition as probable or even possible.
All the buildings requisite for manufacturing this explosive are cheap and flimsy, so that if it did catch fire no loss would ensue. The "plant of machinery" is of small cost in comparison with that used for making black gunpowder, and Schultze's wood-powder is sold at a price commensurate with its cheap production. An explosive is often "better known than liked," such as gun-cotton; but Schultze's wood-powder requires only "to be known to be liked," as a trial of it, lately made for the satisfaction of its readers by the conductors of the Land and Water journal, recently showed. Indeed, it was proved to give more penetration than gunpowder, and it costs less. There is also no smoke, and consequently the second barrel can always be used at once, instead of waiting for the smoke to clear away, as when using black powder.—Belgravia.