produced by electricity . 433 
approached very near each other. When the batteries were 
highly charged, so that the intensity of the electricity was 
higher, the differences were less between the best and worst 
conductors, and they were greater when the charge was ex- 
tremely feeble. Thus, with a fresh charge of about 1 part of 
nitric acid, and 9 parts of water, wires of ~o °f s ^ ver ar >d pla- 
tinum 5 inches long, discharged respectively the electricity of 
30, and 7 double plates. 
Finding that when different portions of the same wire 
plunged in a non-conducting fluid were connected with diffe- 
rent parts of the same battery equally charged, their conduct- 
ing powers appeared in the inverse ratio of their lengths ; so, 
when 6 inches of wire of platinum of discharged the 
electricity of 10 double plates, 3 inches discharged that of 
20, Ji inch that of 40, and 1 inch that of 60; it occurred to 
me that the conducting powers of the different metals might 
be more easily compared in this way, as it would be possible 
to make the contacts in less time than when the batteries were 
changed, and consequently with less variation in the charge. 
Operating in this way, I ascertained that in discharging 
the electricity of 60 pairs of plates, 1 inch of platinum was 
equal to about 6 inches of silver, to 5-j inches of copper, to 4 
of gold, to 3.8 of lead, to about of palladium, and T 8 0 - of 
iron, all the metals being in a cooling fluid medium. 
I found, as might have been expected, that the conducting 
power of a wire for electricity, in batteries of the size and num- 
ber of plates just described, was nearly directly as the mass; 
thus, when a certain length of wire of platinum discharged 1 
battery,* the same length of wire of six times the weight dis- 
charged 6 batteries ; and the effect was exactly the same, pro- 
* A foot of this wire weighed 1.13 grains, a foot of the other 6.7 grains. 
