INTENSITY OF BATTERIES. 



73 



copper in the battery, and the one inch of solution of sulphate of 

 copper in the second or decomposition cell, is 90 or nine-tenths, only 

 yielding one -tenth of the electricity which the zinc and copper are 

 capable of giving. 



intensity. If we now take another zinc and copper plate of the 

 same size as the former, and arrange them in the acid solution, and 

 connect them with the copper plates in the decomposition cell, as 

 shown in fig. 4, and keep them in action the same length of time 

 as in the former experiments, there will be dissolved from the zinc 

 about 19 grains, and deposited 

 upon the copper plate attached 

 to the zinc in the decomposition 

 cell 18 grains of copper. 



If three zincs and coppers be 

 arranged as described and placed 

 in the acid, there will be dis- 

 solved from the zinc plate 26 

 grains, and deposited upon the 

 copper 25 grains. If 6 pairs 



zinc and copper be arranged as above, and placed in acid, there will 

 be deposited 36 grains of copper, which we will also take as the 

 measure of what is dissolved from the zinc : and if 9 pairs of zinc 

 and copper be used, there will be deposited 43 grains, and so on 

 until the quantity dissolved from each zinc, or deposited on the 

 copper plate, be 100, equal to that obtained by the close contact of 

 the zinc and copper in acid, which will require upwards of 30 pairs 

 of zinc and copper. It must be borne in mind that the same quantity 

 of zinc will be dissolved from every plate in the arrangement : thus, 

 in 9 pairs where 43 grains were deposited, there would be dissolved 

 from every zinc in the battery 45 grains. 



It will now be apparent that the use of several pairs in the battery 

 is to overcome resistance, by which quantity is gained at the same 

 time up to a given point ; but quantity gained by this means is 

 expensive. The 10 grains deposited by the single pair of zinc and 

 copper only require 10 grains of zinc, but the 43 grains by the 9 

 pair would require 405 grains of zinc to be dissolved. 



Relative intensity o f Batteries. Different batteries have different 

 degrees of power to overcome resistance, greater intensity. The 

 following experiments will illustrate this : A single pair of a Wol- 

 laston's, Smee's, and Grove's batteries were fitted up as nearly equal 

 in circumstances as the different arrangements would allow ; each 

 exposing the same surface of zinc, and connected with electrodes 

 placed in a solution of sulphate of copper, first 1 inch apart, then 2 

 inches, 3 inches, and 4 inches half-an-hour in each. They were 

 then reversed, beginning with the electrodes at 4 inches and coming 



