Chemical Science. 39 i 



portion of the powder is first dried and the loss of water 

 ascertained ; the nitre is then obtained by washing the powder, 

 evaporating the solution, and fusing the nitre. To obtain the 

 sulphur, 5 grains of powder, 5 of sub-carbonate of potassa, 5 

 of nitre, and 20 of common salt, all of them free from sulphuric 

 acid, are mixed very intimately, and placed on the fire in a 

 platinum vessel. The sulphur burns slowly, and the mass be- 

 comes white. It is then dissolved, and the solution being 

 saturated with nitric or muriatic acid, the sulphuric acid is pre- 

 cipitated by muriate of baryta, the quantity of sulphate of baryta 

 ascertained, and the sulphur estimated from its weight. The 

 sulphate of baryta may either be collected on a filter and 

 weighed, or it may be estimated by using a solution of muriate 

 of baryta of known strength, adding it carefully until precipi- 

 tation ceases ; the quantity of solution used, gives by a direct 

 proportion the quantity of sulphur in the gun-powder. The 

 charcoal is estimated from the loss of weight. 



Potassa, with some precaution, may be used for the sub- 

 cartonate, and a capsule, a matrass, or even a tube of glass, 

 may be used instead of the platinum capsule. — Annales de 

 Chimie, xvi. p. 437. 



10. On firing Gxm-Powder by Electricity, by M. Leuthwaite. 



Dear Sir, — I have been induced to try a few experiments 

 on the firing of gun-powder by means of the electrical shock, 

 with the view of ascertaining the effect produced by making 

 various fluids part of the conducting chain for the discharge. 

 This inflammation has generally been considered as difficult to 

 be produced. Probably these observations may tend to lessen 

 the difficulty, and illustrate, at the same time, the conducting 

 power of fluids for electricity. 



The jar made use of contained one square foot of coated 

 surface, and when charged with sufficient intensity to raise the 

 quadrant electrometer to 90°, always discharged itself spon- 

 taneously. 



The glass tube used was six inches long, the bore -j'^ of an 

 inch in diameter. A cork was fitted into each end, through 

 which a brass wire was introduced, and the capacity of the tube 

 was filled with different fluids. 



I first ascertained from the mean of several experiments, that 

 the gun-powder could not be fired through water, when the 

 quadrant electrometer stood at a less number of degrees than 

 60, at which it always fired. 



I then filled the same tube with sulphuric ether, and found 

 from the mean of several experiments, that it would not fire 

 the powder at a less number of degrees than 60. But when 

 the tube was filled with alcohol, it always fired the powder 

 at 30°. 



2 D 2 



