VOL. XXXVII.^ PHILOSOPHICAL TRANSACTIONS. 567 



the thread was attracted towards that side of it ; when the tube was removed 

 slovvl) , the thread returned to the centre of the receiver ; but when moved 

 swiftly, the thread was attracted by the opposite side of the receiver. When 

 the hand was held near the receiver, and moved hastily from it, the thread was 

 attracted by the opposite side, as before. This seemed at first difficult to ac- 

 count for ; but on further consideration, they concluded it proceeded from the 

 motion of the air made by the tube, and in the other case by that of the hand, 

 which took off" the attraction from that side, and not on the other side ; so that 

 by this means the balance of the attraction was taken off. 



They made another experiment, by suspending a thread on the top of a small 

 receiver, and whelming a large one over it ; then by first rubbing this, and 

 holding the rubbed tube near it, the thread in the middle receiver was attracted 

 to that side of it where the tube was held. 



^n Experiment, slioiuing that Attraction is communicated through opacoiis as 

 tvell as transparent Bodies, not in vacuo. — There was taken a large hand bell, 

 the clapper being first taken out, and a cork suspended by a thread from the 

 top of the bell, the cork being smeared over with honey: then the bell was set 

 on a piece of coach-glass, which had been vvell rubbed, on which the leaf-brass 

 was laid ; then the tube being rubbed, and held near the handle of the bell, 

 and afterwards near the top and side of the same, the bell being taken off, there 

 were several pieces of the leaf-brass sticking to the honeyed cork that had been 

 attracted by it : it appeared also that some other pieces had been attracted by 

 the bell, being removed from the places they were left in, when covered 

 by it. 



Some time after Mr. Wheler mentioned an experiment he had made in 

 vacuo. He took a small receiver, and in it suspended a thread, and over this 4 

 other receivers, all exhausted, and the thread was attracted through all the 5 

 receivers; and he thought the attraction was rather stronger than before, when 

 a single receiver only was made use of; but instead of wet leather, he made use 

 of a cement Mr. G. had recommended to him, viz. bees-wax and turpentine, 

 which was what Mr. Boyle used in his experiments with the air-pump, and that, 

 as he had told him, the attractions would probably be much stronger ; the 

 steams of the wet leather taking off some of the attracting force. 



Mr. Gray proceeds to give some account of the experiments made at Mr. 

 Godfrey's : the first of which was giving an attraction by the tube to a boy sus- 

 pended on hair-lines; when also, by the intervention of a line of communica- 

 tion, the attractive virtue passes to another boy that stands at several feet distant 

 from him. The next is an experiment of the attractive power communicated to 

 the boy standing on rosin. 



