fluid conductors wlien transmitting the electric current. 169 
refute this distinction, will require experiments which it is 
easy to imagine, but which I have not yet had an opportunity 
of making. At first sight, indeed, the phenomena in ques- 
tion present a considerable analogy to the electro-magnetic 
vortices observed in the fluid metals ; but on presenting very 
powerful magnets to the mercury, while under the circum- 
stances above described, in various positions, I have never 
been able to perceive any influence exerted by them in acce- 
lerating, retarding, or deviating the currents ; and moreover, 
these are incomparably more forcible in proportion to the 
electric powers used, than the motions produced by the action 
of magnets, 
14. In consequence of this superior energy of action, the 
phenomena which form the subject of this Paper, furnish a 
test, perhaps, the most sensible vet known of the developement 
of feeble Voltaic powers. I constructed a small battery of zinc 
and copper wires twisted together, each pair being two inches 
long from the point of junction, and the wires of an inch 
thick. Ten pairs of these, excited by extremely dilute nitric 
acid, caused a rapid rotation in mercury, interposed under 
sulphuric acid between the poles, and a regular advance of 
phenomena. The sluggish electricity of a single pair of plates may be compared 
to air, rendered dense and less elastic by excessive cold, while the active charge of 
a powerful battery, or the spark of an ordinary electrical machine, is in this view 
assimilated to air with all its energies exalted, and its density diminished by violent 
heat. The same quantity in weight may pass through the same conducting pipe in 
the same time ; but in the one case the motion of each molecule will be compara- 
tively much slower, and the actual quantity present at any instant of the discharge 
(e. g. an inch in length) of the conductor, much greater than in the other. I am 
well aware that this is merely an analogical representation of facts, and of course in- 
accurate, but it serves to explain the distinction in the text. 
MDCCCXXIV. Z 
