1064 Mr. wilson ’ s Experiments 
fary to charge the jar belonging to it (on account of 
its thicknefs) than what we had employed in our firft 
trials. 
Upon an application to Dr. higgins he favoured" me 
with the ufe of his machine; the cylinder of which, 
when excited with the affiftance of his amalgama, ached 
fo powerfully, that it charged the jar, accompanying 
the new inftrument, very readily. 
We began the experiments where the electrometer 
was ft rack at the greateft diftance, and then adjufted the 
diftances of the ball and- point from the copper ball ac- 
cordingly; fo that if the point was ftruck (when they 
were adjufted) the moving of the ball — d part of an inch 
would occafion the ball to be ftruck in preference to the 
point, and vice verfa. Afterwards we leffened the ftrik- 
ing diftance of the electrometer in every experiment till 
we attained the leaft diftance. 
Upon reverting part of the apparatus, as in fig. 3. all 
thofe experiments were repeated again ; the copper ball 
being put neareft to the glafs in the place of the forked 
part, and the forked part in the place of the copper ball. 
This fet of experiments being compleated, we made 
others, where the ball only was oppofed; and after them, 
where the point only was oppofed to the copper ball. 
Having 
