[ 3 2 5 ] 
Exp. 1 6. But, after a little time, the balls feparated 
an inch or more, and remained fo for fome time. 
In this ftate they were eledrified minus ; for they 
receded from the amber. 
The 'Tourmalin , in thefe circumftances, was fup- 
plied with the elednc fluid from the wood and balls, 
as appears from the preceding experiments, when the 
heated glafs was applied ; fo that the balls muft have 
been in a minus hate, and fome part of the wood in 
a plus one : becaufe of the like refiftance at the fur- 
face to be overcome, where an accumulation of the 
fluid muft have been caufed before it could pafs to 
the Tourmalin ; as appears by Lord Charles Caven- 
di/Jfs experiment. 
Glafs eledrified minus , and applied in the fame 
manner, produced the like effed. As to the method 
of eledrifying glafs minus , it will be fhewn pre- 
fently. 
Exp. 17. Upon bringing my finger near the convex 
fide, the balls receded farther from each other , as 
they did in the thirteenth experiment : and, on re- 
peating the approach, the balls receded a little more, 
unlefs the ftone was become too cold. 
The approach of the finger , therefore, conduded 
the fluid from the flone , more readily than the air 
furrounding it. 
Exp. 18. On removing the Tourmalin the leaft 
from the wood, the balls approached nearer each 
other, and continued to do fo as the ftone was removed 
farther off ; neverthelefs they were eledrified minus , 
though in a lefs degree. 
Exp. 19. I then removed it intirely, and the balls 
receded , but to a greater difance than at any time 
before 
