upon the Leyden PbiaL 1001 
Seeing fo great a difference between the two experi- 
ments, I prdered fuch an apparatus to be made as I 
thought would be the leaft exceptionable for the pur- 
pofes of determining the fa6t upon which thefe different 
appearances feemed to depend ; namely, a perfect and an 
imperfect circuit of communication with the Leyden 
phial. 
In the contriving of this inftrument it appeared ma- 
terial, in order to have it anfwer the fame end as Mr. 
lane’s electrometer, that the feveral experiments to be 
tried with it might be compared with each other in a 
more accurate manner. 
The circuit of communication was divided into two 
parts. A bent rod of brafs, with a ball of the fame me- 
tal, three quarters of an inch in diameter, ferewed on to 
the upper extremity of it, and a copper ball, five inches 
in diameter, ferewed on to the lower end, formed one of 
the parts. This part was fupported by a Hand of wood 
that had a cap of brafs at the top, into which the brafs 
rod was occafionally ferewed. 
The other part of the circuit confifted of a brafs rod 
alfo, one end of which branched out in the form of a 
fork with two prongs, that pointed towards the center of 
the copper ball; and thofe prongs were fo conftrudted, 
Vol. LXVIII. 6 1 that 
