MECHANICS AND USEFUL ARTS. 103 



amongst each other, the less proportion of the inert fibre is re- 

 quired to produce a given retardation in the burning ; conse- 

 quently there should be as intimate a mixture of the two classes 

 of fibres as possible. 



He employs yarn, the cotton or fibre of which has been con- 

 verted by acid into pyroxyline, before and after being formed into 

 yarn. When the manufacture is for large or small arms, he has 

 found it best not to employ more than 30 per cent, of the inert 

 cotton with 70 per cent, of pyroxyline, when such fibres are re- 

 spectively made separately into yarns, and are woven or inter- 

 laced into fabrics, and when the interspersion of the fibres is stiil 

 more intimate, as is the case in pulping the fibres and making 

 paper of mixtures thereof. For sporting purposes, about 15 per 

 cent, of the unconverted fibre makes excellent paper, and about 

 30 grains by weight of this paper rolled into a cylinder make 

 a proper charge when used with about one ounce of shot. Meek. 

 Mag. 



Mr. Abel, of the Woolwich Arsenal, has received a patent for a 

 new method of preparing gun-cotton for general purposes which 

 renders it safe and convenient to use. The invention has for its 

 object to assimilate the physical condition of gun-cotton as nearly 

 as possible to that of gunpowder, by mechanically converting it 

 into a solid conglomerate state, and imparting to it either a granu- 

 lar or other suitable form that will present the exact amount of 

 surface and compactness required for obtaining a certain rapidity 

 or intensity of combustion, lie claims: 



"First, reducing gun-cotton to a pulp, and consolidating such 

 pulp with or without the aid of pressure into the form of sheets, 

 discs, granules, cvlinders. or other solid forms, either with or with- 



' ^j */ 



out the admixture of binding materials. 



" Second, combining with gun-cotton reduced to a pulp gun- 

 cotton in a fibrous state, and consolidating such mixture into sheets, 

 discs, granules, cylinders, or other solid forms, either with or 

 without the admixture of binding materials. 



" Third, combining soluble and insoluble gun-cotton, either 

 when both are in a state of pulp, or when one is in a state of pulp 

 and the other in a fibrous condition, and consolidating such mix- 

 tures into cylinders, sheets, discs, granules, or other solid forms, 

 either with or without the admixture of binding materials. 



" Fourth, subjecting mixtures of soluble and insoluble gun-cot- 

 ton, either when both are in a fibrous condition, or when both are 

 in a state of pulp, or when one only is in a state of pulp and the 

 other in a fibrous condition, to the action of solvents of the solu- 

 ble gun-cotton, either alone or with the employment of pressure, 

 so as to effect the consolidation of the same. 



"Fifth, the application to the surface of the consolidated gun- 

 cotton of a solution of the soluble forms of gun-cotton, or of shel- 

 lac, or other suitable gums or resins." 



It would be difficult to over-estimate the value of this discov- 

 ery. By its means the patentee has succeeded in moderating the 

 violence of the combustion to almost any desired extent, and has 

 thus removed the chief, if not the only, source of danger attend- 



