79 



a » {fm} ° 2 ° + 2 ( ^° 5 > 3 H0 ) = ^{sio} °«> + 4 [ m *> H0 }* 



It seems the greatest care is necessary for the purification of the cot- 

 ton fibres. General Baron Yon Leuk has invented a system, known as 

 the*" Austrian Method." Mr.Haddon's compound, C 36 H 21 (9 N0 4 ) O 30 , is 

 identical with that of the Austrian trinitrocellulose, C 12 H 7 (3 N0 4 ) O 10 ; 

 it is not of any use in the preparation of collodion, but, as Mr. Glad- 

 stone observes, it is Baron Yon Leuk's gun-cotton. It has been kept 

 unaltered for fifteen years ; it is bat slightly hygroscopic, and when 

 exploded in a confined space is free from ash ; its explosive temperature 

 is 136° C. (277°E.). Baron Yon Leuk treats his gun-cotton with a solu- 

 tion of the silicate of potash (water gas). The amount of silica set free 

 on the cotton by the carbonic acid of the atmosphere is really of service 

 in retarding combustion. Neither nitrous fumes nor prussic acid are 

 among the gases evolved — the one an animal poison, the other a corro- 

 sive agent. Karolys found it to contain neither of them, but to consist 

 of nitrogen, carbonic acid, carbonic oxide, water, a small quantity of 

 hydrogen, and light carburetted hydrogen, and these are comparatively 

 harmless ; and it is distinctly in evidence that practically the gun is less 

 injured by repeated charges of gun-cotton than of gunpowder, and that 

 the men in casemates suffer less from its fumes. It is almost impossi- 

 ble for it to explode during the process of manufacture, since the cotton 

 is always immersed in liquid unless during the final drying. Again, 

 it may be submerged in water, and only used according as wanted, as it 

 is most easily dried ; its destruction in the act of combustion is com- 

 plete, being wholly resolved into its component gases, and no residuum 

 left in the gun ; it produces no recoil, and does not heat the bore in the 

 slightest degree, even under the action of repeated discharges. Scott 

 Russell, Esq., E. R. S., has shown that the waste in gunpowder (average) 

 is sixty-eight per cent, its own weight, only thirty-two per cent, being 

 useful. General Yon Leuk has succeeded in timing the velocity of the 

 explosion. In his hands it possesses either one foot per second, or one 

 foot in tooo of a second. The General uses it in the proportion of one- 

 fourth to one-third weight of powder, occupying lyV of the length of 

 the powder cartridge. Experiments made by the Austrian Committee 

 show that 100 rounds could be fired of gun-cotton against thirty rounds 

 of gunpowder : 100 rounds of gun-cotton were fired from a 6-pounder 

 in thirty-four minutes, the gun being raised to 122° E., while in the 

 case of gunpowder an equal number of rounds raised the gun to such a 

 temperature that water easily evaporated. The comparative advantages 

 of gun-cotton and gunpowder for producing high velocities may be shown 

 from the following table :— With a Krupp's cast-steel gun (6-pounder), 

 the ordinary charge of 30 ounces of powder produced a velocity of 

 1-338 feet per second; and with 13 J ounces of gun-cotton a velocity 



* See Edin. Phil. Mag., vol. xxxi., p. 519. 



