100 Experimental Philosophy. [Lecture 8. 



vain to give the power of attraction to metals, by 

 rubbing, hammering, and heating, he conceived 

 a suspicion, that as a glass tube, when rubbed in 

 the dark, communicated its light to other bodies, 

 it might possibly be made to communicate also 

 its power of attraction. He provided himself, 

 therefore, with a glass tube three feet five inches 

 long, and near an inch and one-fifth in diameter. 

 The ends of the tube were stopped with cork, 

 . and he found that when the tube was excited by 

 friction, a feather was attracted as powerfully by 

 the cork as by the tube itself. To convince him- 

 self more fully, he procured a small ivory ball, 

 which he fixed to a stick of deal four inches long, 

 and thrust into the cork ; and he found that it 

 attracted and repelled the feather even with more 

 vigour than the cork itself. He afterwards fixed 

 the ball to a longer stick, and even to a piece of 

 wire, with the same success. Lastly, he attached 

 it to a piece of packthread, and hung it from a 

 high balcony, where he found that, by rubbing 

 the tube, he enabled the ball to attract light bodies 

 in the court below. 



His next attempt was to examine whether this 

 power acted as well horizontally as perpendicu- 

 larly. With this view he made a loop of cord, which 

 he hung to a nail in one of the beams of the ceiling, 

 and ran his packthread, which had the ivory ball 

 at the end, through the loop ; but in this state he 

 found, to his utter mortification, that his ball 

 had totally lost the power of attraction. On 



