568 PHILOSOPHICAL TRANSACTIONS. [aNNO 1732. 



June 16, 1731, in the morning, Mr. Gray made the following experiment 

 on the boy, causing him to become attractive by suspending him on hair-lines. 

 There was taken two pieces of white rosin, made into round flat cakes of rather 

 more than 8 inches diameter, and 1 inches thick. These were laid down on 

 the floor of his chamber, so near together, that the boy might stand with one 

 foot on one, and the other on the other cake of rosin : then the leaf-brass be- 

 ing laid under his hands, the tube rubbed, and held near his legs, caused both 

 his hands to attract and repel the leaf-brass to the height of several inches : or 

 when there was laid leaf- brass under one hand, and the tube held near the other 

 hand, there was an attraction communicated to the farther one ; and when the 

 tube was applied either to his hands or feet, there was an attraction given to 

 his clothes ; so that a piece of white thread being held by one end, the other 

 end would be attracted at near the distance of a foot ; so that the attraction is 

 altogether as strong, if not stronger, than when the boy was suspended on hair- 

 lines. 



Now as to the first experiment at Mr. Godfrey's : one of the boys being sus- 

 pended on the hair-lines, and the other standing on the two cakes of rosin, the 

 boys holding hands with each other, under the boy's hand that stood on the 

 rosin was laid the leaf-brass ; tiien the tube being rubbed, and held near the 

 boy's feet that hung on the hair-lines, the hand of the boy that stood on the 

 rosin attracted strongly. Then there was taken a 4-foot rule, and given to the 

 boys to hold by each end, and the same virtue of attraction was given to the 

 other boy as before. After this, a line of packthread was given them to take 

 hold of by the ends, and then an attraction was communicated from one end to 

 the other, with as much vigour as by any of the other methods beforemen- 

 tioned. This experiment was made Sept. 13, 1732. 



Sept. 14, Mr, Gray first made the following experiment. There was taken a 

 rod, which was composed partly of wood and partly cane : it was 24 feet in 

 length, and in form not unlike two fishing rods supposed joined together at 

 their larger ends. This rod was suspended horizontally by two threads of silk : 

 over this, at about 1 feet from the end, was suspended a small hazel wand, 

 about 5 feet long, at right angles to it, but not touching the rod : then going 

 to the other end of the rod, the tube being excited and held near it, repeating 

 the same 3 or 4 times as usual, and going to the hazel wand with a small white 

 thread, he found that it was attracted when held near any part of it. The next 

 day he repeated the experiment, and found that by suspending the wand at 

 several heights, he could perceive there was an attraction, when it was at the 

 height of more than 12 inches. 



Sept, 29, Mr. Gray repeated the experiment on two boys ; first setting one 



