middle of a circuit of about three yards of brafs wire, 
confiderably thicker than the iron, and flretched in 
two right lines, fufpended on lilken firings. The ' 
length of the iron wire, melted in thefecircumhances, 
was about three inches. I then took the fame brafs 
wire, and fixing pins into a board of baked wood, 
twilled it about them, making it turn in a very great 
number of acute angles, and I put three inches of the 
fame iron wire in the middle of this crooked circuit, 
that I had done in the flraight one j fo that the eledtric 
matter in the explofion was obliged to make a great 
number of turns at acute angles, before it could come 
to the iron wire ^ but I always found that the fame 
length of iron wire was melted in thefe circumflances 
as in the other, and not the leaf! difference was per- 
ceived in the force. 
But though the form of the wire through which an 
explofion paffed, made no difference in ‘its force, I 
found a very remarkable difference occafioned by the 
length of the circuit in wires of the fame thicknefs 5 
and which, I own, furprized me very much. 
In order to afcertain the pradlicability of firing 
mines by eledlrical explofions, I took twenty two 
yards of fmall brafs wire (but fo thick, however, that 
I could not have melted the leafl part of it by the 
force of any battery I have ever conflrudled), and ex- 
tending it along a dry boarded floor, with a fmall 
piece of iron wire, and a cartridge of gunpowder 
about it, in the place that was mofl remote from the 
battery, I found that, upon the difcharge, the wire 
was not melted, nor the gunpowder exploded ^ alfo 
the report was very faint. In other circumflances, a 
charge of the fame battery was able to melt more than 
VoL. LIX. K. nine 
X' 
