GUNCOTTON is the name originally as signed to the material produced by Schoenbein, of Basle, Switzerland, in 1845 by treating cotton with a mixture of strong nitric and sulphuric acids. The discovery that starch, woody fibre, and similar substances give rise to the forma tion of highly combustible bodies when acted upon by concentrated nitric acid is attributed to Braconnot in 1832, and he styled the bodies so produced generically xyloidine. Six years later Pelouze took up this subject and extended his investigations to the behavior of cotton, paper and vegetable substances generally, and later Dumas prepared from paper this means the substance which he called ntiramidine. No practical result followed these observations until the discovery by Schoenbein of the advantages which followed the use of the acid mixture; a discovery which was also independently made by Boettger, of Franicfort, in 1847 and by Knop, of Hanover, and Taylor, of England, in 1847. The discovery aroused the liveliest expectations which were stimulated by the facts that the ex plosive was much more powerful than gun powder and that when used as a propellant it gave little or no smoke. Experiments and tests were begun shortly after with the new explosive in Germany, France, Austria, England, Russia, and the United States with a view of utilizing it as a substitute for gunpowder in guns. Unfortu nately the material, as manufactured, was found to be not only so irregular in action that it was likely at any time to burst the piece, but also so unstable as to give rise to numerous accidents so that, especially after the serious and, at the time, inexplicable explosions at Vincennes and Bouchet in France, and Faversham in England, the experiments were discontinued except in Austria, where Baron von Lenk gave the matter close and long-continued study and came to the conclusion that the grave defects noted were not inherent in the material, but were due to the imperfect and irregular methods of manu facture, the failure to purify the cotton before treatment with the acid, and the failure to purify the guncotton and free it completely from acids after treatment. Following these convictions he improved the method of manu facture to such an extent that in 1862 the Aus trian army had 30 batteries provided with gun cotton cartridges made up by twisting the fibre into yarns which were braided together, but the spontaneous explosions at the magazine at Sim mering in 1862 and at Steinfeld in 1865, together with the fact that the guncotton cartridges still gave at unexpected times abnormal pressures led to its further use in Austria being inter dicted.
Von Lenk's process of manufacture was pat ented in England in 1862 and the Prentice Brothers began manufacturing under this pro cess in 1864. In 1865 Abel patented an improve ment of the process which was so successful in use that it gave guncotton a prominent and permanent place among explosive substances, and this process is followed to-day. The cotton when treated with the acid is in the fibrous con dition which so well characterizes it, and under the microscope these fibres are seen to be hol low so that each is really a capillary or hair-like tube. Von Lenk had shown that cotton con tains not only cellulose as the main component of its structure but that there were smaller and variable quantities of other substances naturally present besides foreign bodies accidentally pres ent, and that it was necessary to get the cellu lose in a pure and dry condition before treating it with acid. He, too, with others, had proved that the purity, strength and proportions of the acids used and the time and temperature of immersion of the cotton in the acid mixture affected very materially the character of the substance produced, while it was essential that every trace of free acid should be removed from the product, since a most minute quantity of sulphuric acid acts continuously and cumula tively on the guncotton and causes a progres sively increasing rate of decomposition. Yet von Lenk and all others up to this time pro duced the guncotton in the same long staple form as the cotton from which it was made. It was evident to Abel's mind that as the dry cot ton was immersed in the acid mixture the capil lary tubes, of which it was composed, would suck up the liquid acid and retain it with such force and in such a manner as to make its re moval by wringing, or washing with or in water or by neutralization with alkalies, extremely difficult and uncertain, and to remedy this Abel proposed to pulp the guncotton through which the fibres would be cut into such short lengths that the acids could be completely and readily removed from the interiors of the tubes while furthermore this pulped material could by mold ing and pressure be shaped into any desired forms and dimensions.