Knight's Mechanical Encyclopedia, G., Gun-cot′ton.

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Gun-cot′ton.

The first notice of the discovery of gun-cotton was made by Braconnet, in 1833, who detailed the action of nitric acid on starch, sawdust, linen, and cotton. He called it xyloidine.

Pelouse, in 1838, called attention to this compound.

Dumas, in 1843, again cited a mode of preparing, and made suggestions for the application.

Schonbein, in 1846, brought forward his plan of using nitric and sulphuric acids. It was described by W. H. Ellet of Columbia, S. C., in 1846.

Baron Von Lenk, 1864, used cotton skeins instead of employing the wool in masses, thus rendering the saturation more complete and the manipulation easier. The loose cotton thread is first boiled in an alkaline solution and afterwards placed in a cylinder with perforated wire sides, making from 600 to 800 revolutions per minute, by which the alkali is expressed; it is then washed in clean water and again subjected to the action of the cylinder, after which it is thoroughly dried by exposure to air and by heating in a chamber to about 120°.

One-pound charges of the cotton thus prepared are next immersed in a mixture composed of 3 parts of sulphuric to 1 of nitric acid, which has been allowed to cool from 48 to 72 hours; the vessels containing the cotton and acid being surrounded with cold water to prevent undue heating during the chemical action which ensues.

The cotton is then placed on a strainer and expressed until it retains but about ten times its weight of acids, when it is removed to an earthenware jar, surrounded by water as before, where it is allowed to remain forty-eight hours to insure its complete conversion into “trinitro cellulose,” or gun-cotton. It is then taken out and washed by plunging suddenly in water, to prevent heating; and afterwards placed in a tank of running water for forty-eight hours, and dried in the centrifugal machine; this bathing and draining process is repeated six times, when the cotton is finally washed in a warm alkaline solution to remove all the uncombined acid. Up to this period the cotton has been in a greater or less degree damp, since it was first subjected to the action of the acids, but after assuming its final shape is dried in charges of twenty pounds in fire-proof cages. See also Revy's process, 1865; and appendix to A. L. Holley's “Treatise on ordnance and armor.”

Mr. Abel, of the Woolwich (England) Dock-Yard Chemical Department, has discovered that the explosive force of gun-cotton, like that of nitro-glycerine, may be developed by the exposure of the substance to the sudden concussion produced by a detonation, and that if exploded by that agency the suddenness and consequent violence of its action greatly exceeds that of its explosion by means of a highly heated body of flame.

Charges for sporting or blasting purposes are sometimes put up with a core of raw cotton, to diminish the force of explosion.

Wet gun-cotton is of course proof against explosion by heat, but it has been found that its explosive energy is rather increased than diminished when wet and fired by percussion. A body of gun-cotton thrown into the sea in a net, with a protected priming of dry cotton and fulminate, will explode with as much force as if confined in a water-tight vessel.

The rapidity with which gun-cotton detonates has been computed at 20,000 feet per second. Its energy is from two to four times that of gunpowder. See explosives.

Gun-cotton is not soluble in alcohol or ether, but in a mixture of the two it dissolves readily, giving rise to a perfectly colorless mucilaginous liquid. known as collodion. This dries quickly to a hard skin, quite structureless, and possessing considerable strength. It is used in surgery, and also, in conjunction with iodides and bromides, to form the collodion of the photographer. See pyroxyline.

1877.

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Knight's Mechanical Encyclopedia
Knight, Ed.

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Gun-cot′ton.

Knight's Mechanical Encyclopedia Knight, Ed.

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Gun-cot′ton.

Knight's Mechanical Encyclopedia
Knight, Ed.