: " ; 
230 Mr. Lane on Electric Conduction in Metals. 
and spread outward laterally ; in E'uchirus they are.thrown forward 
in the line of the body, and. are flexed like the letter pA ; and in 
Candacia they have nearly a similar position, but have the ex- 
tremity flexed towards the head instead of away from it. - | 
'l'he maxillipeds may always be distinguished from the first 
pair of legs by the sete, which are setulose in the former, and 
naked in the latter. 
Anr. X.—On the Law of Electric Conduction n Metals ; by | 
JoxarHAN H. Laxwk. 
My attention was first directed. to the su ject of the. law of 
conduction by reading a paper by Prof. Morse, published in this 
Journal, Vol. xtv, p. 390, first series, accompanied by a commu- 
nication from Prof. Draper. 'lhese comnáuniecations gave me 
the impression that the law commonly recéived was not "well as- 
certained, and it was under this impressiofi that the experiments 
given in the following paper were made. But since it was 
written, I have found that I had misfaken 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 thóught to controvert it; but 
they have either been explained, ér are not 1n their nature satis- 
factory. Stil, my own method/of experiment appears to pos- 
sess advantages over any that I Kave seen ; and notwithstanding 
the imperfect manner in which it has been carried out, it has 
given results more exactly corfesponding with the supposed law. 
I must say, however, that njy experiments have by no means 
been sufficiently extended, for those given are all I have pan 
touching this question. H 
1. Supposing dloctricgtl to be a fluid, and an electric current 
to be no more than the mótion of this fluid through a conductor, 
which, at the same time,; / opposes a resistance to its motion, it 1s 
a natural inference, thaf as electric motion is known to "dédult 
from difference of tensioh, so conversely, there is always a differ- 
ence of tension in the different parts of a conductor, while con- 
ducting a current—a regular gradation in the quantity of elec- 
