150 
PROFESSOR DANIELL ON VOLTAIC COMBINATIONS. 
Calculation. 
Experiment. 
5 treble cells, 
5 — 2’49 
2-51 
Cubic inches. 
= 0-738 = 16-97 
Cubic inches. 
17-0 
1 + 1-725 ~ 
3-391 " 
5 quadruple cells. 
5 - 2-49 
2-51 
= 0-8437 = 19-4 
20'0 
i + 1-725 
2-975 
10 single cells, 
10 - 2-49 
7-51 
= 0-6408 = 14-73 
15-25 
10 + 1-725 — 
11-725 
10 double cells, 
10 — 2-49 
7-51 
= 1-116 =25-68 
25-5 
T + 1*725 “ 
6-725 
20 single cells. 
20 - 2-49 
17-51 
= 0-8062 = 18-54 
18-00. 
20 + 1*725 — 
21-725 
The maximum work of a single circuit of this battery was found to be 9’95 grs. of 
zinc per minute, which is equivalent to twenty-three cubic inches of the mixed gases. 
A similar agreement of this independent result which has been taken as the unit in 
the preceding table (for ^ = 1^ with those which would be afforded by any com- 
bination of cells taken as the foundation of the calculation may be also observed, as 
in the case of the table deduced from experiments with the smaller battery. 
When a number of cells of different power are included in the same circuit, the 
expression becomes 
n E + n' E' — e , 
( n + v!) R + r 5 
supposing that R remains the same as in the regular circuit, and E' represents the 
electromotive force of the new element, and n' the number of the new elements in- 
cluded. 
It will further, on a little consideration, be obvious why a half-zinc rod may be 
substituted for a whole one in a series, without any perceptible diminution of the 
effect, as I found upon a former occasion*. The effect of diminishing the length of 
the rod is principally to increase the distances between the metals, as the dimensions 
of the mean section of the electrolyte will scarcely be altered, owing to the compara- 
tively small surface of the generating metal, even when entire. The general formula 
will then become 
n E — e . 
n' R + n" R' + r “ A > 
when n' represents the number of ordinary zinc rods, n" the number of shortened 
ones, and R' the increased resistance offered by each of the latter. 
The mean distance between the metals will, perhaps, be increased one-third by 
* Philosophical Transactions, 1836, p. 127. 
