644 Mr. nairne’s Account of 
the brafs point ; at the other end of the tube, and at the 
end of this wire, was a brafs ball, eight-tenths of an inch 
diameter. 
The brafs cap at this extremity of the tube which is 
fartheft from the receiver was made round, and placed fo 
as to be in contact with the prime conductor of an elec- 
trical machine. 
I now firft put fome vitriolic acid into the receiver, as 
a means of being able to make the remaining contents 
-of the receiver, when exhaufted as much as poffible, to 
confift of permanent air only, unadulterated with va- 
pour ; and as the receiver was the fame I had ufed in my 
foregoing experiments, there were two pear-gages fitted 
to It, which pear-gages I pufhed down into the cifterns 
of quickfilver at different times, and the pump was 
worked as in my former experiments for ten minutes : 
heat of the room 59 0 . 
The electrical machine was worked during the whole 
. of the experiments. 
E X P E» 
