VOL 



. XLI.] rHILOSOPHlCAL TRANSACTIONS. 307 



Prop. I. Bodies made Electrical, by communicating with an Electrical Body 



excited by Friction, are in a state of Repulsion with regard to such excited 



Bodies. 



Exper. 1 . — Mr. W. hung a fine white thread by a loop, to a horizontal blue 

 silk, line, about 4 feet long, tied at each end, and at about a foot distance from 

 it, placed a glass tube 2-i- feet long nearly, and one inch and quarter diameter, 

 fixed in the centre of a circular piece of wood supported on three brass screws, so 

 that the tube and pendulous thread were parallel to each other. The tube being 

 rubbed, the thread was attracted and repelled 7 or 8 times J in very good wea- 

 ther it moved to and from the lube 12 times, at above one foot distance. 

 He then tied a piece of new smooth packthread to the top of the tube, and to 

 the loop of the thread hanging down as before, and again excited the tube: 

 the thread, without coming once towards the tube, went into and continued 

 in a state of repulsion ; but if he only touched the communicating packthread 

 with a finger, the white thread immediately hastened to the tube : and on hang- 

 ing another long piece of packthread, which reached the ground, to the com- 

 municating packthread, and again rubbing the tube, the pendulous white thread 

 was so far from going into a state of repulsion, that it became attracted to the 

 tube, and continued so, without showing the least tendency to a state of re- 

 pulsion, as long as the virtue of tlie tube lasted. 



Exper. 2. He tied a piece of small cane, about l6 inches long, and one 

 fourth of an inch diameter at one end, and a little more at the other, at right 

 angles to the top of the tube, fixed in the same pedestal as before, and making 

 unequal arms with it ; and at the end of the larger arm, a piece of stick trans- 

 versely, about 6 inches long, so as it might slide backwards and forwards to 

 and from the tube. This moveable short stick at one end supported a very fine 

 white thread, at the other a very fine blue silk, by which means now a silk and 

 a thread both at the same time hanging parallel to the tube. The thread, after 

 the tube was rubbed, first was attracted, but then immediately repelled, and 

 continued a considerable time in a state of repulsion ; but on tying to the end 

 of the shorter arm of cane, a piece of long packthread, which reached down on 

 the table, and rubbing the tube again, the thread continued in a state of at- 

 traction, without being once repelled during the whole virtue of the tube, as 

 in the preceding experiment. Yet the silk, whether the long packthread was 

 added or not to the shorter arm of the cane, continued constantly attracted 

 towards the tube ; but on putting a short silk only 6 inches long, in the same 

 circumstances, it would, after some time rubbing the tube, turn into a state of 

 repulsion, the upper part first bending from the tube, and the lower part to- 



R R 2 



