3l6 PHILOSOPHICAL TRANSACTIONS. [aNNO \7'3g. 



the cake had been excited by Mr. Wheler ; but they had no regular revolutions 

 at all, though several very manifest motions were made with the hand, to try if 

 a projectile motion might by that means be given to the pendulous body. Mr. 

 Wheler had tried the same thing with his servant ; from whence it is reasonable 

 to conclude, that it is necessary, that the same person who excited the cake, 

 should likewise hold the thread ; as if there were some analogy between the 

 effluvia excited by the clapping of the hand on the cake, and the effluvia which 

 may be communicated along from the hand which holds the thread to the piece 

 of cork at the end of it. And this seems to be the reason of what the late Mr. 

 Grey said, viz. That there was something in the human hand essential to 

 the experiment, which he had not yet found in any other supporter of the 

 thread. 



Some Remarks on the Electrical Circular Experiment* of the late Stephen 

 Gray, F.R.S. By Granvile Wheler, Esq. N° 453, p. 118. 



Some uncommon circumstances led Mr. W. to make Mr. Gray's circular 

 experiment in the following manner. While he excited a cake of rosin and 

 bees-wax, 10 inches diameter, by clapping with his hand, he let the ivory ball 

 remain in a basin of water ; then shaking off the drops, placed it in the cen- 

 tre, and with his right hand held a fine thread, about 8 or Q inches long, having 

 one end rolled up into a little ball, and the other, for about an inch, reduced 

 to its greatest fineness, to only one fibre, himself and hand being supported on 

 the back of a chair. The success was, he had a great many revolutions, to the 

 number of 50, from west to east ; but at first not so regular as towards the 

 last, at first describing only about 1 -third part of the circumference at a 

 time, and after standing still a little, describing another third part. He might 

 probably have had a great many more revolutions, but being tired, he was 

 forced to rest himself, which he did for 10 minutes, then took up the thread 

 again. The thread stood repelled at some distance, without making any revo- 

 lutions, and at last only made half a one the contrary way to what it did be- 

 fore; but on wetting it, by drawing it 2 or 3 times over the surface of the 

 water, it made again 20 more revolutions from west to east, only at a smaller 

 distance from the ball, for the water must make it heavier, but full as regular 

 as before, and rather quicker. The virtue of the cake must now have lasted 

 about 3 quarters of an hour. After resting about 6 minutes, he tried again 

 with the string fresh wetted, the ball and cake continuing as before; and had, 

 to his great surprise, 100 revolutions in the space of about 12 minutes, the 



* See Philos. Trans. N" 441, 444, of the Revolutions of pendulous bodies by electricity. — Orig. 



