GUN-COTTON was first discovered by M. SchiMbein of Basel, and made known in the year 1846. It is prepared with cotton wool, and explodes at Fahr. Gunpowder ex plodes at 600°. In consequence of this, gun cotton may be fired on gunpowder without igniting it. This peculiarity results from the minute division of the cotton fibres ; for mealed powder, or gunpowder dust, will ex• plode at a much lower temperature than grained powder.
Gun cotton may be prepared in various ways. Mr. Taylor made it by saturating cotton wool in a mixture consisting of equal quantities of nitric and sulphuric acids. This must be done as rapidly as possible by press ing the cotton in the mixture with a glass rod. When this is done, it is taken out, and as much as possible of the mixture is squeezed out of it. The cotton is then washed in suc cessive portions of water until it loses all taste of acid. It is then pressed. in a linen cloth and dried. Sawdust, wood-shavings, and any body consisting principally of carbon, may be rendered explosive by preparation in a similar way.
The manufacture and use of these prepara tions are however dangerous, and they have in consequence been prohibited generally in France. Gun cotton is more powerful than gunpowder, i.e., with equal quantities by weight a much greater effect is produced by the cot ton ; in consequence of which there is every probability that it will supersede powder for the purposes of blasting, for which it possesses the important advantage that it does not generate smoke. It remains however to be proved whetherit will answer for military pur poses. The experiments of the French go.. vernment are against it, in consequence of the production of an inconvenient quantity of moisture by its explosion. M. Schlinipein has secured the patent for his preparation in Eng land, and it is manufactured on his account by agents appointed by him. So extremely explosive is this material, that many serious accidents have happened in connection with its manufacture.