We condense from an English exchange a description, of the white, or rather, tawny-colored powder lately devised by Captain Schultze of the Prussian service, and which, under the auspices of at least one London gunmaker, is finding large application among English sportsmen. The progress of manufacture is said to be most safe, as it is most ingenious. Only at the final stage of making this gunpowder is the process subject to any explosive contingency. In illustration of this, the following circumstance should be stated; in July, 1868, the manufactory of Captain Schultze at Potsdam, near Berlin, was consumed, burned quietly to the ground—burned, not exploded. The accident is altogether unprecedented; nothing like it could have happened to a manufactory of common black gunpowder. We now come to the process of manufacture. The inventor begins by taking any of the common woods (he keeps the woods steeped in water) which have acquired celebrity for yielding gunpowder charcoal, and sawing them transversely into plates of the required thickness by a veneer saw. The plaies, when sliced, are laid under a manifold punch and submitted to pressure, whereby grains of not merely definite and varying size, but definite and unvarying shape (a matter of some moment as influencing the constancy of impaction), result. Grains are thus evolved at the very commencement of the manufacturing operation, unlike what happens in the case of black gunpowder, wherein the operation of grainage is the last operation but one—glazing : and sometimes, powder not being invariably glazed," the last absolutely. The punched grains, being collected in a mass, are subjected to a treatment of chemical washing, whereby calcareous and various other impurities are separated, leaving hardly anything 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-cutton material, by digestion with a mixture of sulphuric and nitric acids. Practically it is found that absolutely perfected xyloidine (of which ordinary gun-cutton 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, Captain Schultze affirms, subject to neither of these contingencies. Chemists 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, afr the time of firing, will be necessarily utilized towards 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, arts, stored away in bulk not necessarily to be endowed with final explosive energy until the time of package, transport, and consignment. Only one treatment lias to be carried out,, and it is very simple. The ligneous grains have to be cimrged 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 saltpeter) is employed; but in elaborating certain varieties of white powder Captain Schultze prefers a&d uses nitrate of baryta. Having traced the new powcte-r 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, espe-pecially under prolonged moisture, of the sulphur and niter of ordinary powder, whereby sulphide of potassium should result. Practice is confirmatory; under the condition indi-bated, sulphide of potassium, more or less, does result, and proportionate to the extent of decomposition is the powder deteriorated. Inasmuch as the Schultzegunpowder 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. The specific gravity of the Schultze gunpowder may be roundly taken at half the specific gravity of ordinary gun-powder; or, in other words, for equal weights of the two, the bulk of Scliultze's powder will be double that of i ts rival. Hereupon an important question is raised, the drift of which will be obvious to any practical gunner. Is the available projectile force of one volume of Scliultze's powder equivalent to the available projectile force of two volumes of black powder ? If not, it may be averred with tolerable confidence that the new material could never come into extensive practical use as a gunnery-projectile. This consideration seems to have been duly considered by Captain Schultze. His powder is so devised and elaborated that each effective charge shall occupy equally the same space as a charge of common powder would have occupied. All his " gunnery arrangements, therefore, are taken on the basis of matching volume against volume, the equivalent in weight to one volume of his powder being two volumes of ordinary gunpowder. It has taken fair hold on the English sportsman's appreciation, as before stated; but, as may be assumed, there are drawbacks, real or alleged, to its use, otherwise it would have gone further than it has to replace ordinary black powder. The chief disparagement alleged against it, is the difficulty, rather than the impossibility, of measuring out charges with the accuracy needful to practice. It is necessary to weigh the charges, gunmakers aver, if identity of result be contemplated. This allegation, if well borne out, implies a serious defect. Practical people will grasp its full purport, however much the unpracticed may make light of it.
This article was originally published with the title "The Schultz White Gunpowder" in Scientific American 20, 21, 321-322 (May 1869)