* & 
230 Mr. Lane on Electric Conduction in Metals. 
and spread outward laterally ; in Huchirus they are thrown forward 
in the line of the body, and are flexed like the letter 4 ; and in 
Candacia they have nearly a similar position, but have the ex- 
tremity flexed towards the head instead of away from it. 
The maxillipeds may always be distinguished from the first 
pair of legs by the sete, which are setwlose in the former, and 
naked in the latter. 
Arr. X.—On the Law of Electric Conduction in Metals ; by 
~ Jonaruan H. Lane. 
‘My attention was first directed to. the subject of the law of 
conduction by reading a paper by Prof. Morse, published in this 
Journal, Vol. xiv, p. 390, first series, accompanied by a commu- 
nication from Prof. Draper. These communications gave me _ 
the impression that the law commonly received was not well as- 
certained, and it was under this impression that the experiments 
given in the following paper were made. But since it was 
written, I have found that I had mistaken the particular aim 
of Prof. Morse’s experiments, which did not profess superior ac- 
curacy, but were only intended as experiments on a large scale 
by way of verification. Experiments have long since been made 
by different electricians, which afford strong support to the law 
in question, while others were thought to controvert it; but 
they have either been explained, or are not in their nature satis- 
factory. Still, my own method of experiment appears to pos- 
sess advantages over any that I have seen; and notwithstanding 
the imperfect manner in which it has been carried out, it has 
given results more exactly corresponding with the supposed law. 
I must say, however, that my experiments have by no means 
been sufficiently extended, for those given are all I have made 
touching this question. oy 
1. Supposing electricity to be a fluid, and an electric current 
to be no more than the motion of this fluid through a conductor, 
which, at the same time, opposes a resistance to its motion, it is 
a natural inference, that as electric motion is known to result 
from difference of tension, so conversely, there is always a differ- 
ence of tension in the different parts of a conductor, while coD- 
ducting a current—a regular gradation in the quantity of elee- 
pat He 
ee 
oor 
Pies, 
FoR 
