of Gunpowder by Electricity. 175 



that of the larger jar, the whole circuit being thirty-one feet 

 nine inches. A similar effect was produced by the charge of 

 a phial containing forty-seven square inches of coating, the 

 extent of the circuit remaining the same as in the above ex- 

 periment. A phial containing only twenty-eight square inches 

 of coating was next employed, and its charge when trans- 

 mitted, produced the immediate inflammation of the gunpow- 

 der, the whole circuit being seven feet nine inches. This is 

 the smallest phial in my possession, but there is no doubt that 

 the experiment might be effected, by this method, with the 

 charge of a phial still smaller. 



After practising for several years the above simple and ef- 

 ficacious method of performing an experiment which has so 

 much, embarrassed electricians, another method was suggested 

 by considering the following well-known fact ; namely, that a 

 very imperfect conductor of the electric fluid, if it has a sharp 

 point and is not too extended, will convey the electricity from 

 the prime conductor, or even from the ball of a charged 

 jar, when presented to either of them, almost as rapidly as a 

 metallic point. It was therefore concluded that if a sharp- 

 pointed piece of wood was substituted for one of the pointed 

 wires, if would convey a portion of the charge adequate to 

 produce the intended effect. Accordingly, a small piece of 

 very dry wood was taken, about three inches long, and a part 

 of it was formed into a very tapering point. This was at- 

 tached to the negative wire of the universal discharger, in such 

 a manner that the wooden point projected beyond the end of 

 the metallic point one inch and a half. The wooden point 

 and the metallic point of the positive wire were then placed 

 at the distance of half an inch from each other, and some 

 gunpowder was laid in the interval between them. The ex- 

 tremity of the chain, instead of being placed so as to make a 

 second interruption, as in the former method, was now put in 

 contact with the outside of the jar. A pretty strong charge 

 was then communicated to the jar ; and as soon as the ball of 

 the discharging rod touched that of the jar, the gunpowder 

 was inflamed, and nearly at the same instant the residue of 

 the charge passed through the flame of the gunpowder with a 

 smart explosion. This unexpected and curious phenomenon 

 very much surprised me ; and the experiment was repeated se- 

 veral times, in order to ascertain the certainty of the fact ; and 

 with a view to render it more evident, the points were placed 

 further from each other, and by carefully noticing and ad- 

 justing the intensity of the charge to the distance between 

 the points, the inflammation of the gunpowder, when the Jirst 

 portion of the charge was transmitted, was seen to take place 



a per- 



