126 
MR. DANIELL ON VOLTAIC COMBINATIONS. 
tained that no alteration, within the distance of the generating and conducting plates 
of the battery, produced any difference in the results. 
'This rendered the non-influence of variation of surface still more remarkable ; and 
wishing to push the observation to the utmost, I reduced the plates of a voltameter 
to the width of one eighth of an inch, retaining the same height of three inches, and 
still found its efficacy unimpaired. I next thrust two platinum wires one tenth of an 
inch diameter through a cork closing the mouth of a glass tube, exposing about two 
inches of each to the dilute acid without any diminution of effect, the battery gene- 
rating in all these experiments at the rate of 2 - 7 cubic inches per five minutes. 
When I even covered the wires with a resinous cement so as to have only one fourth 
of an inch of each exposed, the gases evolved in the same time amounted to 2‘3 cubic 
inches. I ultimately coated the wires entirely with cement, and carefully bared their 
mere points with a file, when they still gave off the gases at the rate of 0-8 cubic 
inch per five minutes ; and in this case the currents of the gases instead of rising 
at once from the points of the horizontal wires seemed to be projected forward into 
the liquid with some force. This independence of the results upon the metallic sur- 
faces of the voltameter is curiously contrasted with the paramount influence of the 
surface of the conducting plates of the cells of the battery, but is probably owing to 
the absence of any active chemical affinity assisting or retarding the main current 
which circulates. 
In the prosecution of my experiments I now began to perceive that it was by no 
means necessary to attend so closely to the supply of fresh acid to the battery as at 
first seemed advisable ; and I ascertained that after an uninterrupted action of five 
hours, without its renewal, the voltameter only indicated a decline from 2 ‘7 to 2‘4. 
It being of great consequence to note to what extent the constancy of the action 
might be independent of the exact adjustment of the acid, I left the battery in con- 
nexion for twenty-four hours, at the expiration of which time 09 cubic inch of the 
mixed gases was collected in the voltameter in a quarter of an hour, or 0 - 3 cubic 
inch per five minutes. The acid was found to be almost perfectly saturated ; a 
very small drop of dilute ammonia occasioning an instantaneous precipitation of ox- 
ide of zinc in the solution, which had a specific gravity of T276. In this state three 
quarters of a fluid ounce of fresh dilute acid was poured upon the top of the solution 
in each cell (the total charge of each cell being about 5^ fluid ounces), when the 
action not only rose to its original amount of 2*7 cubic inches, but to 4 2 cubic 
inches, at which rate of work it kept perfectly steady without any further renewal of 
the acid for four hours. 
This increase of action I could only refer to the superior conducting power of the 
solution of sulphate of zinc; and two important points were thus indicated: 1st, that 
the conducting power of the electrolyte in the battery might be increased with great 
advantage ; and 2ndly, that the quantity of the circulating force was still more inde- 
pendent of the surface of the generating metal than my experiments had yet shown 
