DISTANCE BETWEEN THE PLATES. 27 



The following is the proportional rate which we have found on 

 the large scale tinder the most favourable circumstances. A new 

 zinc plate, amalgamated as described, working continuously 



24 hours, zinc lost 12^ ounces Copper deposited 12 ounces ; 



48 hours, zinc lost 20^ ounces Copper deposited 17 ounces ; 



60 hours, zinc lost 34 ounces Copper deposited 24-J ounces. 



From these and similar data we found that the most economical 

 way of using zincs is the following: after being in the battery twenty- 

 four hours, they are to be taken out, brushed, and laid aside ; after 

 other twenty-four hours, they are to be again brushed, and immediately 

 re-amalgamated: if these directions are attended to, ^ ounce of mer- 

 cury will be sufficient for one foot square of zinc, both sides. 



The advantages of proper amalgamation will be made more evi- 

 dent in the sequel. We have only to add here, in consequence of 

 an oft-expressed fear of the danger of working with quicksilver, that 

 no apprehension need be felt : the skin does not absorb it, and there 

 being no heat required in the operation that could convert the mer- 

 cury into vapour, the only state in which it is dangerous, no saliva- 

 tion can take place. 



Distance between the Batter? Plates. To return again to the 



battery-cell the zinc and copper in acid (Jig. 4:) it will be found 

 that if the two metals be put very close to each other, the action 

 will be much more rapid than when they are far apart. It will also 

 be found that, allowing the zinc and copper to be kept at one distance, 

 but the wires in the decomposition-cell to be put at different dis- 

 tances, similar results will take place. When the wires are close 

 the action in the battery-cell will be more powerful than when the 

 two wires are put farther apart : these properties are applicable to 

 all batteries and decomposition-cells of every kind. The following 

 results will give an idea of the relations of these several conditions: 

 1st. One pair of copper and zinc plates, measuring superficially 6 

 square inches, were immersed in a solution consisting of 1 acid to 35 

 water : plates of copper of equal size to those of zinc and copper 

 were laid in the decomposition-cell, which was then filled with a 

 liquid of equal strength to that in the battery-cell: the plates in the 

 battery-cell and the decomposition -cell were then placed one inch 

 apart : in four hours 



The zinc in the battery-cell lost by dissolving lOj grains; 



The copper dissolved in decomposition-cell 10 grains. 

 2d. The battery plates were put 12 inches apart, and the plates in 

 decomposition 1 inch apart : in four hours 



There were dissolved in the battery-cell, zinc 7 grains ; 



In decomposition-cell, copper 6 grains. 



3d. The battery plates were placed 1 inch apart, and the plates in 

 decomposition-cell 12 inches apart : in four hours 



