and on the Construction of Voltaic Batteries. 85 



The first, or A, had its elementary couples of equal size; 

 each of its zinc plates measured 10£ square inches, and each 

 of its copper ones 168 square inches. 



The second, or B, had its couples of unequal sizes, as seen 

 in this table. 



1st couple had zinc= 1 square inch, and copper = 16 square inches. 



2nd zinc = 2 square inches, and copper = 32 • 



3 r J zinc = 4 and copper = 64 ■ 



4th zinc = 8 and copper = 128 



5th zinc =16 and copper = 256 



6th zinc = 32 and copper = 512 



Total 63 square inches. 1008 square inches. 



The third battery, or C, had its couples also unequal^ but 

 increasing from the first one by a different progression. I 

 need only write out the dimensions of the zinc, each corre- 

 sponding copper being sixteen times larger. 



1st couple had zinc = 8 square inches "] copper 



2nd zinc = 9 



3rd zinc =10 



4th zinc = 11 



5th zinc =12 



6th zinc = 13 



Total 63 1008 ditto. 



The electricity developed by each of these batteries was 

 passed in succession through a voltameter holding acidulated 

 water, during times of 30 minutes each ; when 



A yielded of mixed gases, 1*3 cub. inch, 

 B yielded do. do. 0*7 cub. inch, 

 C yielded do. do. 1*1 cub. inch, 

 results which verify the conclusion drawn from the preceding 

 experiments, and which prove besides that even when the dif- 

 ference in the sizes of the component circles of the battery is as 

 trifling as in C, their inequality is attended too with a marked 

 inferiority of action. 



Since the above experiments were made I have contrived 

 an apparatus by which such kinds of experiments, and many 

 others of great importance to the science, may be conducted 

 with the greatest possible precision and certainty. Its prin- 

 ciple depends essentially on the substitution, in the place of 

 amalgamated plates, of ajluid amalgam, formed by the union 

 of 20 parts by weight of mercury and 1 of zinc. But as 

 this paper has already exceeded any reasonable limits, I will 

 not trespass on your patience with any description of its form 

 or operation beyond that of merely stating that it appears 

 to me to be admirably calculated for deciding many of the 



