THE TECHNOLOGIST. [.Sept. 1, 1864. 



50 ON THE MECHANICAL NATURE AND 



therefore, a service from gun-cotton which shall be the contrary of 

 destructive to, or disruptive of, the chamber in which it does the work 

 of giving motion to the projectile. 



This moderated and modified work gun-cotton can also perform ; 

 and it is the modern discovery of General Lenk which has enabled us 

 to moderate and modify gun-cotton to this gentler service. He dis- 

 covered how to organise, arrange, and dispose mechanically of gun-cotton 

 in such a way that it should be three times stronger than gunpowder. 

 Accordingly, one of his charges of gun-cotton, weighing 16 ounces, pro- 

 jected a 12-pound solid round shot with a speed of 1,426 feet a second, 

 while a charge of gunpowder of 49 ounces gave the same shot a speed 

 of 1,400 feet a second. One-third of the weight of gun-cotton exceeded, 

 therefore, the threefold weight of gunpowder in useful effect. 



II. Is gun-cotton more convenient than gunpowder ? This is a larger 

 and more various question than the former, and divides itself into 

 various subdivisions. 



It is w y ell known to sportsmen, to soldiers, to artillerymen, that 

 gunpowder fouls a gun. A foul residue of soot, sulphur, and potash 

 soils the inside of the gun after every charge. The gun must, somehow, 

 be cleaned after a discharge ; if not it fires worse, recoils more, and 

 ceases to do its best. If the gun be a breech-loading gun, its 

 mechanism is dirtied, and works less easily. Gun-cotton deposits no 

 residue, leaves the gun clean and clear, and the utmost it does is to 

 leave a gentle dew of clear water on the inside of the bore, this water 

 being the condensed steam which forms one of the products of its 

 decomposition. Gun-cotton is, therefore, superior to gunpowder in not 

 fouling the gun, a resvdt favourable both to quicker and more accurate 

 filing. 



It is further a matter of no slight convenience that gun-cotton makes 

 no smoke. In mines the smoke of gunpowder makes the air unbreath- 

 able, and for some time after explosion the miners cannot return to 

 their work. In boring the great tunnel of Mont Cenis through the 

 Alps, the delay from smoke of powder alone will postpone the opening 

 of the line for many months. After a properly-conducted explosion of 

 gun-cotton, the workmen may proceed in their work at once without 

 inconvenience. 



In casemates of fortresses, gunpowder fills the casemates with foul 

 smoke, and the men speedily sink under the exertion of quick firing. 

 By using gun-cotton it was ascertained that the men covdd continue 

 their work unharmed for double the quantity of firing. This is partly 

 attributed to the greater heat, and partly to the foulness of the air pro- 

 duced by gunpowder. 



But it is under the decks of our men-of-war that the greatest benefit 

 is likely to arise from gun-cotton. Not only does the smoke of a broad- 

 side fill the between decks with hot and foul air, but the smoke of the 

 windward guns blinds the sight, and hinders the aim of the leeward. 



