3co Conductors and Non-Conduttors. [Book IV. 



as . to intercept the electric power, and they accord- 

 ingly attempted to remedy this evil by employing a 

 (ilk ftring, which was much ftronger in proportion 

 than a hempen cord. With this apparatus the expe- 

 ment fucceeded far beyond their expectations. En- 

 couraged by this fuccefs, and attributing it wholly to 

 the finenefs of the filk, they proceeded to fupporr the 

 packthread, to which the ball was attached, by very 

 fine brafs and iron wire, but, to their utter ailonifh- 

 ment, found the effect exactly the fame as when they 

 , ufed v the hempen cord ; the electrical virtue utterly 

 pafted away ; while on the other hand, when the pack- 

 thread was fupportcd by a filken cord, they were able 

 to convey the electric virtue feven hundred and fixty- 

 five feet. 



It was evident, therefore, that thefe effects depended 

 upon fome peculiar quality in the filk, which difablcd 

 it from conducting away the electrical power, as the 

 hempenVord and the wire had done. This, probably, 

 immediately led to die difcovery of other non-con- 

 ch icting bodies; and bair t ro/in, glq/s, &c. were pre- 

 iently made ufe of to infulate the bodies which were 

 electrified. The next obvious improvement was to 

 electrify feparate bodies, by placing them upon non- 

 conductors; and in this manner Mr. Grey and his 

 friend Mr. Wheeler electrified a large map, a table 

 cloth, &c. &c. In the latter end of the iame fism- 

 mer, Mr. Grey found that he could electrify a rod as 

 well as a packthread, without inferting any part into 

 his excited tube, and that it only required to be placed 

 Dearly in contact with the apparatus. 



Mr. Grey proceeded to try the effects of electricity 



upon animal bodies. lie fufpended a boy on hair 



lines in a horizontal polition, and bringing the excited 



tube near his feet, he found that leaf brafs was attracted 



2 very 



