52 
to be deficient, and the platina surcharged with electricity, 
and this, under favourable circumstances, may be ascertained 
experimentally ; but when we close the circuit, the current 
circulates so as to produce equilibrium. Now let us repre- 
sent the direction of the currents of two separate pairs of 
elements in a diagram, marking the direction of the currents, 
and then draw the connections as in series; we shall perceive 
that each neighbouring metal becomes closer to the circuit of 
the next; each pair of zinc plates receiving the current 
from the platina of the neighbouring pair, so that whilst 
the zinc plates No. 1 and platina No. 2, mutually exalt 
each other's electro-motive power, the quantity of current, 
or rather the electricity developed, is neutralized. 
The power of any series of voltaic arrangements is pro- 
portionate to the quantity of zinc dissolved in each cell, so 
far as regards the effect on a galvanometer, an electro- 
magnetic machine, or in producing chemical decomposition; 
and the power of the battery, as regards the overcoming 
resistances to the transmission of its powers through con- 
ductors, or through substances to be chemically operated 
upon, is proportionate to the electro-motive force of the 
individual cells, multiplied by the number of cells. There- 
fore the consumption of zinc equivalent to a given amount 
of work, must be multiplied by the number of cells used, 
to enable us to institute a comparison of the various kinds of 
battery, with regard to the consumption of zinc in them ; 
and having ascertained the consumption of zinc, the equiva- 
lent quantity of other materials may be deduced therefrom, 
either by calculation according to chemical equivalents, or, 
if such method be doubtful, from any uncertainty as to 
the nature of the secondary products, as is the case with 
a nitric acid battery, from actual experiment. 
I have, according to the method before pointed out, 
tabulated the results of a considerable number of experi- 
