Experiments iipon Gunpowder. 95 



and so ordered that each particle might be completely 

 surrounded by, and exposed to, the action of the flame 

 of the powder, it would be very soon heated, and possi- 

 bly might be converted into an elastic steam, or vapour, 

 before the bullet could be sensibly removed from its 

 place. To determine this point, I mixed 20 grains of 

 Eethiops mineral very intimately with 145 grains of 

 powder, and charging the piece with this compound, it 

 was loaded with a fit bullet and fired: but the force of 

 the charge was less than that which the powder alone 

 would have exerted, as appears by comparing the 76th 

 and 77th experiments with the 79thc 



Common pulvis fulminans is made of one part of sul- 

 phur, two parts of salt of tartar, and three parts of nitre ; 

 and if we may judge by the report of the explosion, the 

 elastic force of this compound is considerably greater 

 than that of gunpowder. I was willing to see the effect 

 of mixing salt of tartar with gunpowder, and according- 

 ly, having provided some of this alkaline salt in its pur- 

 est state, thoroughly dry, and in a fine powder, I mixed 

 ao grains of it with 145 grains of gunpowder; and upon 

 discharging the bullet with the mixture, I found that the 

 alkaline salt had considerably lessened the force of the 

 powder. See experiment No. 78. 



I next made use of sal ammoniacum. That salt has 

 been found to produce a very large quantity of gas, or 

 elastic vapour, when exposed to heat under certain cir- 

 cumstances; but when 20 grains of it were mixed with 

 a charge of gunpowder, instead of adding to its force, it 

 diminished it very sensibly. See the 80th experiment. 



Most, if not all, the metals, when they are dissolved 

 in proper menstrua^ cause large quantities of gas to 

 be produced, or set at liberty ; and particularly brass, 



