FULMINATING MERCURT. 189 



one, of the best forged iron, consisting of a chamber 0.4 of an inch 

 thick all round, and 0.4 of an inch in calibre ; it was torn open 

 and flawed in many directions, and the gold touch. hole driven out. 

 The barrel into which the breech was screwed was 0.5 of an inch 

 thick ; it was split by a single crack three inches long, but this did 

 not appear to me to be the immediate effect of the explosion. I 

 think the screw of the breech, being suddenly enlarged, acted as a 

 wedge upon the barrel. The ball missed the block of wood, and 

 struck against a wall, which had already been the receptablc of so 

 many bullets, that we could not satisfy ourselves about the impres. 

 sion made by this last. 



** As it was pretty plain that no gun could confine a quantity of 

 the mercurial powder sufficient to project a bullet with a greater 

 force than an ordinary charge of gunpowder, I determined to try 

 its comparative strength in another way. I procured two blocks 

 of wood, very nearly of the same size and strength, and bored 

 them with the same instrument to the same depth. The one was 

 charged with half an ounce of the best Dartford gunpowder, and 

 the other with half an ounce of the mercurial powder ; both were 

 alike buried in sand, and fired by a train communicating with the 

 powders by a small touch-hole. The block containing the gun. 

 powder was simply split into three pieces : that charged with the 

 mercurial powder was burst in every direction, and the parts im. 

 mediately contiguous to the powder were absolutely pounded, yet 

 the whole hung together, whereas the block split by the gun. 

 powder had its parts fairly separated. The sand surrounding the 

 gunpowder was undoubtedly the most disturbed ; in short, the 

 mercurial powder appeared to have acted with the greatest energy, 

 but only within certain limits. 



" The effects of the mercurial powder, in the last experiments, 

 made me believe that it might be confined, during its explosion, in 

 the centre of a hollow glass globe. Having therefore provided such 

 a vessel, seven inches in diameter, and nearly half an inch thick, 

 mounted with brass caps, and a stopcock, I placed ten grains of mer- 

 curial powder on thin paper, laid on iron wire 149th of an inch thick 

 across the paper, through the midst of the powder, and, closing the 

 paper, tied it fast at both extremities with silk to the wire. As 

 the inclosed powder was now attached to the middle of the wire, 

 each end of which was connected with the brass caps, the packet of 

 powder, became by this disposition, fixed in the centre of the 

 globe. Such a charge of an electrical battery was then sent ajorig 



