Chap, i .] Drfcovertes of Mr. Grey. 299 



fruitlefs attempts to make metals attractive by heat- 

 ing, rubbimg, and hammering,' he conceivl a fuf- 

 picion, that as a glafs tube, when rubbe4 in the dark, 

 communicated its light to various bodies, it might 

 poffibly at the fame time communicate its power of 

 attraction to them. In order to put this to the trial, 

 he provided himfelf with a tube three feer five inches 

 lon-g, and near an inch and one-fifth in diameter; 

 the ends of the tube were flopped by cork ; and he 

 found that when the tube was excited, a down feather 

 was attracted as powerfully by the cork as by the 

 tube itfelf. To convince himfelf more completely, 

 he procured a fmall ivory ball, which he fixed at firfl 

 to a flick of fir four inches long, which was thrufl into 

 the cork, and found that it attracted and repelled the 

 feather even with more vigour than the cork itfelf. 

 He afterwards fixed the bill upon long flicks, and 

 upon pieces of brafs and iron wire, with the fame 

 fuccefs; and laflly, attached it to a long piece of 

 packthread, and hung it from a high balcony, in which 

 flate he found, that by rubbing the tube the ball was 

 conflantly enabled to attract light bodies in the court 

 below. 



-His next attempt was to prove, whether this power 

 could be conveyed horizontally as well as perpendi- 

 cularly j with this view he fixed a cord to a nail which 

 was in one of the beams of the ceiling, and making 

 a loop at that end which hung down, he inferted his 

 packthread, with the ball which was at the end of it, 

 through the loop of the cord, and retired with the 

 tube to the other end of the room ; but in this flate 

 he found that his ball had totally loft the power of at- 

 traction. Upon mentioning his difappointed efforts 

 to a friend, it was fuggefted, that the cord which he 

 had ufed to fupport his packthread might be fo coarfe 



as 



