96 Experiments 2ipon Gtmpowder, 



when it is dissolved In nitrous acid. Desirous of seeing 

 if this could be done by the flame, or acid vapour of fired 

 gunpowder, I mixed 10 grains of brass, in a very fine 

 powder, commonly called brass dust (being the. small 

 particles of this metal that fly off^ from the wheel in 

 sharpening pins), with 145 grains of powder, and- with 

 this compound and a fit bullet I loaded my barrel, and 

 discharged it; but the experiment (No. 81) shewed that 

 the force of the powder was not increased by the addition 

 of the brass dust, but the contrary. 



It seems probable, however, that neither brass dust nor 

 sethiops mineral are of themselves capable of diminish- 

 ing the force of gunpowder in any considerable degree, 

 otherwise than by filling up the interstices between the 

 grains, and obstructing the passage of the flame, and so 

 impeding the progress'of the inflammation. And hence 

 it appears how earthy particles and impurities qf all 

 kinds are so very detrimental to gunpowder. It is not 

 that they destroy or alter the properties of any of the 

 bodies of which the powder is composed, but simply by 

 obstructing the progress of the inflammation, that they 

 lessen its force, and render it of little or no value. Too 

 much care, therefore, cannot be taken in manufacturing 

 gunpowder, to free the materials from all heterogeneous 

 matter. 



Of an Attempt to shoot Flame instead of Bullets. 



Having often observed paper and other light bodies 

 to come out of great guns and small-arms inflamed, I 

 was led to try if other inflammable bodies might not be 

 set on fire in like manner, and particularly inflammable 

 fluids ; and I thought, if this could be effected, it might 

 be possible to project such Ignited bodies by the force 



