[ 453 ] 
a minus , and the plain fide a plus , electricity. Thefe 
figns increafed for a time, and then decreafed, till they 
entirely difappeared. When this happened, the 'Tour- 
malin appeared to be of the fame temper, in refpeCt 
to warmth, with the room; and the Therm, was 
raifed to 58. 
The fame degree of warmth, or nearly fo, was 
continued in the room for thirty minutes and more, 
without caufing any alteration; for the Tourmalin 
afforded no ele&ric appearance whatfoever. 
EXPERIMENT II. 
I then removed the Tourmalin with the Therm . 
into the cold room and with equal care *. The fione , 
fome little time after, fhewed figns of electricity again : 
but then, thofe figns were contrary to what had been 
obferved before. For, in this cafe, the convex fide was 
plus , and th t plain fide minus, in nearly the fame time ; 
and thefe figns encreafed alfo for a time, and then 
decreafed, till they entirely vanifhed. When that 
happened, the j tone appeared alfo of the fame temper, 
in refpeCt to coldnefs, with the room. And the 
Therm, was fallen to about 42 0 . During half an 
hour, or more, after that time, the Tourmalin fhew- 
ed no eleCtric figns whatfoever, nor did the Therm . 
fall any lower. 
* It is indifferent which fide of the Tourmalin is moved 
foremoft, provided it be done Jlowly. 
Vol. LIII, 
Nnn 
EX PE- 
