it\ pafling through metallic circuits of any thlcknefs 
whatever ; and that it would prefer a very fhort paf- 
fage thro’ the air, if they were made even of no great 
length. In this method the different degrees of condu.dl- 
ing power in different metals may be tried, ufing me^ 
tallic circuits of the fame length and thicknefs, and 
obferving the difference of the paffage through 
the air in each. N. B. A common jar anfwers as 
well, in thefe experiments, as a large battery. It is 
evident, from many experiments, that the whole fire 
of an explofion does not pafs in the fhorteft and befl 
circuit ; but that, if inferior circuits be open, part 
will pafs in them at the fame time. Of this I made 
the following fatisfa£lory trial. I took an iron chain, 
and laid it upon a table, in contad: with a charged 
jar ; fo that the parts of it made two circuits for the 
difcharge, which I could vary at pleafure ; and I ob- 
ferved that, when one of the circuits was but half an 
inch, and the other more than half a yard j yet, if the 
charge was high, it always went in them both, there 
being confiderable flafhes between the links of the 
remoteft part of the chain. If the charge was weak* 
it palfed in the fhorteft circuit only. 
It is evident, that when the wires of a battery are 
hot in clofe contadt, there muft be feme lofs of force 
6 in 
