C 513 I 
XXXII. Experiments and Observations on a new Appara- 
tus^ called , A Machine for exhibiting perpetual Ele Airi- 
city. In a Letter to the Rev. Dr. Horfley, Sec. R. Sr 
from Mr. William Henly, F. R. S. 
majefty, lately put into my hands a little apparatus,, 
which he called a machine for exhibiting perpetual elec- 
tricity, and informed me, that it was the invention of 
fome foreign gentleman (*). This machine confifted of a. 
circular plate of glafs, about eight inches in diameter, co- 
vered on one fide with a coating of bees-wax and rofin, 
about the fixteenth part of an inch thick. This coat of 
wax, See. being ftrongly excited with a dry warm flan- 
nel, he placed upon it a circular board, of the fame di- 
meniions, coated with tin-foil, and furnifhed with a glafs- 
handle fcrewed to, and handing upright upon it.. Thefe' 
bodies having remained in contact fome feconds, the 
board was railed up by the glafs handle ; when, applying: 
the knuckle to the tin-foil coating, a fnap was heard, a 
fpark been, and a fmall fenfation felt. On replacing the. 
board, and permitting it to remain fome feconds, as before,, 
having touched the tin-foil with a finger, on removing 
it again, and applying the knuckle, as at firlf, the fame- 
(a) I have fince learned from Mr. nairne, thatM. volta, of Ccma, near 
Milan, was die inventor of it. 
REVEREND SIR, 
March 4, 177 6, 
Y ingenious friend Mr. george adams,. 
philofophical inftrument-maker to his. 
phenomena 
