and on the Construction of Voltaic Batteries. 73 



which increase of action (reckoning from the third result) being 

 deducted from the results of the corresponding periods in the 

 former table, will leave that table to show the influence merely 

 of the increased size of the copper plates, which is the point 

 sought for. Therefore the table so corrected stands thus: 



Table No. 4. corrected (from No. 2). 



1 st, copper equal to zinc, loss 4*0 grains 



2nd, : twice the zinc, loss 5*2 — 



3rd, 4 times the zinc, loss ... 6*6 — 



4th, 8 times the zinc, loss ... 8*7 — 



5th, 12 times the zinc, loss ... 14*5 — 



6th, 16 times the zinc, loss ... 18*5 — 



7th, 20 times the zinc, loss ... 15*0 — 



8th, 24 times the zinc, loss ... 14*8 — 



From which it appears that the greatest amount of action be- 

 tween the zinc and the acid is induced when the copper plate 

 is 16 times larger than the zinc. 



But in order further to test the accuracy of these results 

 eight distinct zinc plates were selected, as nearly as possible 

 alike, and the experiments repeated with the aid of a fresh 

 zinc plate during each time, when the results were exactly the 

 same as those exhibited in the corrected table No. 4. 



This table, then, shows the proportion of the copper by 

 which the greatest effect is produced under the then existing 

 conditions of the arrangement. But it does not show us what 

 is the absolute amount of power gained by using this propor- 

 tion in preference to plates of an equal or of any other size ; 

 neither does it show whether the law it establishes will hold 

 good under varying conditions of the action of the arrange- 

 ment ; whether, for instance, if its energy be increased or di- 

 minished, it will still require, to produce the utmost absolute 

 effect, that the copper should be maintained of a size 16 times 

 greater than the zinc. 



To determine the former of these points let the result ob- 

 tained by the plates of equal surface in zinc and copper (which 

 we have in the first line of the above table No. 4) be taken as 

 unity, and the other results reduced by it, when the table will 

 stand thus : 



Table No. 5. reduced (from No. 4). 



1st, copper equal to the zinc, gave, loss 1*0 



2nd, twice the zinc, gave, loss ... 1*3 



3rd, 4 times the zinc, gave, loss 16 



4th, — . 8 times the zinc, gave, loss 2*1 



5th, 12 times the zinc, gave, loss 3*6 



6th, 16 times the zinc, gave, loss 4*6 



7th, 20 times the zinc, gave, loss 3*7 



8th, — . 24 times the zinc, gave, loss 3*7 



Third Series. Vol. 11. No. 64. July 1837. L 



nearly, 



