1821.] an Apparatus for discharging Ordnance. 91 



powder ; for with Col. Yule's apparatus, the time that is required 

 IS very trifling. 



(II.) Having- now stated all that is necessary with regard to 

 the apparatus itself, it remains for me, in the concluding part of 

 this paper, to direct the attention of the Society to several expe- 

 riments performed with it, which present rather extraordinary 

 results. 



At the request of Colonel Yule, I commenced, about the 

 beginning of July last, a number of experiments, with the view 

 of discovering a powder which should never miss inflaming the 

 cartridge ; and I was fortunate enough to hit upon one. All 

 the usual fulminating powders were first tried without success ; 

 the fulminating mercury, when the fifth part of a grain only was 

 used, rent asunder the steel plate at the top (marked 6?), and yet 

 did not reach as far as the gunpowder placed at B. Some of 

 the antimonial preparations were found sometimes to fire the 

 gunpowder, but they left a cake of crocus behind, which stop- 

 ped up the holes, and could not be easily removed. 



The following substances, and a variety of other inflammables, 

 were used, mixed with an equal weight of superoxymuriate of 

 potassa : 



Golden sulphuret of antimony. White lead, 



Black sulphuret of antimony. Litharge, 



Pted precipitate of mercury, Orange lead, 



Chinese vermihon. Flowers of zinc, 



Muriate of mercury. Flowers of sulpb\ir. 



Red oxide of mercury. Rosin, 



Ethiop's mineral. Gum arabic. 



Red oxide of lead. Gum gamboge. 



None of these, however, produced any regular effect, and 

 several of them gave no inflammation at all. 



I shall now add a fist of powders, all of which occasionally 

 pierced the flannel at B, and inflamed the powder below it ; 

 very few of them, however, did so twice successively : 



1. Superoxymuriate of potassa 5*0 



Sublimed sulphur 2*0 



Charcoal powder I'O 



This and No. 3 are the worst on the Hst. 



2. Superoxymuriate of potassa 12*0 



Flowers of sulphur 4*0 



Charcoal powder 2*0 



Gum arabic powder 1*0 



This and No. 9 are fourth best. 



3. Superoxymuriate of potassa 18*0 



Flowers of sulphur 3*0 



Gum arabic. • . , 1*0 ^ . 



