[ 2 Q1 ] 
fome concern In this event ; and the fuppofition was 
verified by faCt. For, infulating a jar, charged 
pofitively, I obferved, that when I touched the out- 
fide coating laft (as is commonly done in fetting it 
down) and made the difcharge through good con- 
ductors, they were all electrified pofitively ; and 
bodies placed near the circuit were the fame. On 
the contrary, if, after placing the jar upon the ftand, 
I touched the knob of the wire, communicating with 
the infide, fo as to take off all its redundant eleCtri- 
ci ty 5 both the circuit and the neighbouring bodies 
contracted negative electricity. 
I had at this time quite forgot that ^Epinus had 
made the fame obfervation, on difcharging a plate of 
air, mentioned in the Hiftory of EleCtricity, p. 273 j 
but, confidering what he fays on that fubjeCt, I find 
he was miftaken with refpeCt to the realon of this 
experiment not fiacceeding with Dr. Franklin and 
others, who had always afferted, that the eleCtric 
circuit contracts no electricity at all by a difcharge. 
For he fays, that the furfaces with which the doCtor 
tried the experiment, were not large enough to make 
the effeCt fenfible-; and that the diftance of the 
metal plates was likewife too fmall, as, he fays, it 
neceffarily mult be in the charging of glal's : whereas 
1 could give the infulated circuit as fenfible electri- 
city with a common jar, as he could with his plate 
of air ; and much more depends upon the height of 
the charge, which muff Have been inconfiderable in 
the plate of air, than the quantity of fur face ; which, 
however, may be increafed at pleafure, by multiply- 
ing jars in batteries. 
Vol. LX. D d I found*, 
