PROFESSOR DANIELL ON VOLTAIC COMBINATIONS. 
143 
Each rod separately would have been capable, in its position, of producing the full 
effect of one ; but each was screened by the two others from the full aspect of the 
conducting cylinder, and but a slight advantage was gained from the combination 
by a slight increase of the section of the electrolyte, uncompensated by any increase 
of distance. 
I anticipated that, if each rod were removed as nearly as possible to the sides of 
the cylinder, so as to be equidistant from the other two, the screening influence could 
not take place to the same extent, and that a greatly-increased effect would be pro- 
duced. A glance at the annexed diagram will explain the difference of the two 
arrangements ; fig. 1. representing a section of the first, and fig. 2. of the second. 
Fig. 1. Fig. 2. 
Upon making the experiment, as in fig. 2, with the rods and cylinder of the last 
experiment, the result was increased to 3*1. 
I also tested the conclusion with the large battery of ten cells of four inches dia- 
meter, and obtained from single rods 10| cubic inches of mixed gases per minute, 
and from two rods placed as near to the sides of the cylinders as possible, fourteen 
cubic inches per minute. 
The law of the exact compensation of the greater resistance arising from the in- 
creased thickness of the electrolyte, by the extension of the area of its mean section, 
is of course only mathematically correct where the interior wire is infinitely small, 
but practically the half-inch rods bear so small a proportion to the cylinders which 
I have been in the habit of employing, that the results are not materially affected by 
their dimensions. When, however, the interior cylinders are enlarged, the thickness 
of the electrolyte is decreased, and the area of its section increased at the same time, 
and the circulating force rapidly augments. The results are easily submitted to cal- 
culation. 
Fig. 3. 
2 ins. z 
m\s 
mis 
c 1 inch 2 
mis 
Fig. 4. 
~ 1 — 
100 50 0 100 75 50 
Let c c, fig. 3, represent a section of a copper cylinder four inches in diameter, and 
