Remarks on the Galvanic Battery. 139 



the plates was reduced to 4 inches, gave similar results. 

 But the amount of liquid saturated daily was nearly twice 

 as great, with but a small increase in the quantity of elec- 

 tricity generated; showing a much greater local action. 



The experiments with a Daniell's element of the usual 

 size, using a porous cell 2 J inches in diameter and 7 inches 

 hio-h. o-ave 5*7 Cubic inches for the amount of liquid satu- 

 rated daily, during the normal condition of the element. 

 As q. was nearly double that of Hill's element, and the 

 amount of liquid saturated, less in proportion, it shows 

 less local action. From these experiments it follows that 

 once having determined q. the length of time the battery 

 will maintain the current at its normal force can readily 

 be computed; since it depends entirely on the capacity of 

 the cell holding the sulphate of zinc. With a porous cell 

 of the usual size, when no external resistance is intro- 

 duced, the battery will begin to decrease at the end of 

 three days and at the end of five days there will be scarcely 

 any action. On the contrary with Hill's element, of the 

 size before described, q. will continue uniform for more 

 than thirty days, and will be but little less at the end of 

 fifty days. Most of the writers on galvanism seem to 

 imagine that sulphuric acid is essential for exciting the 

 battery, but our experiments show that this is not the 

 case ; in fact we consider it a detriment; for if too great a 

 quantity is used, crystals of sulphate of zinc are deposited 

 on the zinc, thereby greatly lessening q. It seems to me 

 that the only office of the sulphuric acid, is to make the 

 water a better conductor ; since nitric acid, muriatic acid, 

 salt, sulphate of copper, or sulphate of zinc, will answer 

 equally well. By using a solution of s. z. of a certain 

 specific gravity, the same quantity and electro-motive 

 force is obtained, as with sulphuric acid. This is also true 

 for Grove's and the bi-chromate of potash battery. 



