[ 3^8 ] 
that mentioned in the 9th experiment. In a few 
minutes, the minus, electricity difappeared, and the 
plus continuing, diffufed itfelf into the place of the 
other ; fo that now the whole was eledtrified plus. 
Exp. 22. The experiment fo far fucceeding, in- 
duced me to make ule of a lefs piece of glafs, that I 
might have the whole eleSirifed minus. Upon making 
the experiment, it anfwered accordingly. 
Thefe advances led me to obferve the power of 
electrifying this fmall piece of glafs and the Tourma- 
lin at different dijlances. 
Exp. 23. I expofed the fmall piece of glafs to the 
prime conductor, at the diftance of two feet, which 
was the fame as before in the 21ft experiment, and 
obferved a minus ele Sir i city at both Jur faces. 
Exp. 24. As I moved the glafs nearer , to a certain 
diftance, it was more fenfibly electrified minus ; and 
after that, on moving it ftill nearer, the minus ap- 
pearance was lefs and lefs feniible, till it came within 
the diftance of about one inch , and then it was elec- 
trified plus on both ftdes. 
Thefe laft experiments are farther confirmations of 
the permeability oj glafs. 
Exp. 25. This plus eledricity in the glafs I found 
might be changed to a minus once again, by remov- 
ing the glafs, and holding it for a time at a greater di- 
ftance : which is another proof of the repulfve power 
of this fuid. 
Exp. 26. The Tourmalin afforded like appearances 
when in the fame circumltances ; with this difference, 
that they were caufed at greater diftances than thofe 
of the glafs; and particularly the plus electricity was 
acquired at the diftance of one foot, or more. 
• From 
