and on the Construction of Voltaic Batteries. 77 



Then, taking the results of equal plates (or the first line of 

 the above) as unity, this table reduced stands thus : 

 Table No. 7- (No. 6. reduced.) 



1st. Equal sizes = 1*0 



2nd. Zinc increased by 2 = 2 



3rd. by 4 = 30 



4th. by 6 = 31 



5th. by 8 = 27 V nearly. 



6th. by 12 = 27 



7th. by 16 = 27 



8th. by 20 = 27 



9th. by 24 = 27 J 



Showing by the first (No. 6.) that the greatest effect fol- 

 lows upon the employment of a zinc plate six or seven time9 

 larger than the copper ; and by the second table (No. 7.) that 

 the absolute amount of action gained (when that is at its maxi- 

 mum) is about three times beyond that produced when the 

 plates are equal. 



To sum up the results brought out by the foregoing investi- 

 gation, it appears that both the zinc and copper plates exer- 

 cise a definite influence when either is made the larger in any 

 voltaic arrangement ; but that that influence is different in de- 

 gree in each case ; that when the zinc is the larger, its full 

 effect is obtained when it is about seven times the greater, and 

 the absolute amount of that effect is three compared with 

 equal plates as one : but that when the copper is the greater 

 in the arrangement, then its full effect is not reached till it 

 measure sixteen times greater than the zinc, and the total 

 absolute amount gained, over equal plates, is four and a half. 



Having ascertained these facts, I now proceeded to trace 

 their influence in compound arrangements, as well as in the 

 simple elementary ones to which the experiments had hitherto 

 been restricted. Accordingly I prepared three batteries, con- 

 sisting of a series of ten couples each. 



The first (A) had the zinc and copper plates of equal size, 

 and each plate presented a surface of four square inches to 

 the action of the acid. 



The second (B) had zinc plates of the same dimensions as 

 those of A, but were connected to copper ones sixteen times 

 larger, that is, the zinc were each four and the cor/per sixty - 

 four square inches in surface. 



The third battery was furnished with copper plates the same 

 size as those in A ; but the zinc ones were seven times larger, 

 that is, the copper ones were four square inches each, and the 

 zinc ones twenty-eight. 



These batteries being each excited by an acid mixture of 

 the same strength, and their action continued through equal 



