[ 20 5 3 
difference is, that this detached part of the. charge 
leaves the common track, and returns to it again, in 
the very fame place. 
Several remarkable partial circuits occurred in the 
courfe of my experiments before, particularly one, 
mentioned in the Hiffory of Electricity, p. 692, in 
which, part only of the explofion paffed in the fhort- 
eft way, while another part of it took a circuit, con- 
lifting of the fame materials, thirty times as long ; 
and another, mentioned, p. 691, where one circuit 
was made through a thick rod of metal, and ano- 
ther, at the fame time, through the open air. * 
That there is an admiffion and an explwion of 
the eleCtric matter, in this lateral explofion, feems 
evident, from this circumftance, that it is far more 
confiderable when the body that receives it is large, 
than when it is fmall. In the former cafe, there is 
room for the eleCtric matter, natural to the body, to 
retire, upon the admiflion of the foreign electricity 
belonging to the charge ; whereas, in the latter cafe, 
there is not room for it. When I placed a fmall 
brafs ball, of about a quarter of an inch in dia- 
meter, near the circuit, I could not perceive that 
it was at all affeCted by any lateral explofion j and 
the fpark was very inconfiderable, when I placed a 
needle, about two inches in length, to receive it j but 
when I connected the large tube above mentioned, 
by means of a pretty thick iron wire, to any body 
whatever, that was placed in the neighbourhood of 
the circuit, I have (with a jar of only half a lquare 
foot of coating glafs) made the lateral explofion, an 
inch or more in length, confifting of a very full and 
bright fpark of eledric fire. Infulated bodies, of 
about 
