52 Laws of the Elementary Voltaic Battery. 



The above results exhibit, very beautifully, the great relative effi- 

 ciency of the copper in galvanic arrangements. Comparing Nos. 2 

 and 5 with Nos. 3 and 12, it appears, consistently with nearly all our 

 former results, that the increase of zinc produces no increase of ac- 

 tion, although corapafed with Nos. 1, 4, and 13, some increase is 

 shewn. Comparing Nos. 3 and 12 with Nos. 6, 8, 10, and 14, we 

 perceive a vast disparity in the amount of galvanic action; 170° to 

 30°. This mode of experiment, furnishes an easy and impressive- 

 class room illustration. 



15. In all the preceding experiments, the increase of action be- 

 came very slow, when the copper surface was a large multiple of 

 the zinc, so that in fact, after a certain point, no additional effect was 

 produced by the addition of more copper surface. Attributing this 

 to the great distance of the lower portions of the copper slip from the 

 small immersed surface of Zinc, we inferred, that by placing the cop- 

 per in two portions on opposite sides of the zinc, still preserving the 

 same distance from it, a much greater action vvould take place. 

 This inference moreover, was favored by the consideration, that in 

 Dr. Wollaston's construction of the battery, the plates are thus arrang- 

 ed. We determined, however, to put the matter to the test of ex- 

 periment. 



Plates similar to those formerly used, were arranged with a view 

 to this new series of observations — the two exterior plates, whether 

 of copper or zinc, being connected by an arched wire carefully sol- 

 dered to both, to the middle and highest point of which another wire 

 was soldered, reaching to one of the cups of the galvanometer. By 

 this means, two outside plates acted electrically as one. The let- 

 ters Z and C, will sufficiently indicate the arrangement of the plates. 



c. z. c. c. z. z. c. z. z. c. 



2 in. 2 in. 2 in. 4 in. 2 in. 2 in. 2 in. 2. in. 4. in. 2 in. 

 r 82° - 106° - 73° - 76° 



2' 82 - 106 - 72 - 72 



3' 82 - 106 - 72 - 72 



These rather unexpected results, lead directly to the inference, 

 that Wollaston's plan of enclosing the zinc on both sides with copper, 

 is really less advantageous than allowing the copper to extend to a 

 double length on one side of the zinc plate. The fact of the copper 

 being presented to both zinc surfaces, being, in contradiction of all 

 our theoretical notions, of no advantage whatever. 



