Voltaic Batteries^ S^c. 173 



ment will be increased by increasing the size of either plate 

 of the couple employed ; but the extent to which this increase 

 in amount of action can be carried is limited. The rate in 

 which this increase proceeds, and the influence upon that rate 

 by the different conditions of strength of acid mixture, and 

 relative distances of the plates, together with some other at- 

 tendant phaenomena, are examined in a succeeding section. 

 My present purpose is to state the fact of this increase, and 

 not to determine either its rate or its extent. 



128. In the investigation now on hand, the amount of vol- 

 taic action obtained by a small couple of the same magnitude 

 as those used in the last section, and having its plates at the 

 relative distance of ^ of an inch, is used as a standard of com- 

 parison. 



129. The amount of action given by this couple being de- 

 termined at this first position, in an acid mixture of uniform 

 strength and dimensions, its copper plate is then removed to 

 other and greater distances from the zinc, and the amounts 

 given at those positions likewise determined. But the rate 

 at which the amount decreases upon this increase in distance 

 has already been determined by the experiments in the last 

 section. 



1 30. It is now proposed at these several distances, to in- 

 crease the size of the copper plates till the amount of action 

 obtained shall become equal to that yielded by the standard 

 couple at the first or standard position ; the immediate object 

 being to determine the relation between the sizes of the plates 

 required to produce this amount, and the distances at which 

 they are required. 



131. By way of illustration, let the distance to which the 

 small copper plate is removed from the zinc be supposed to 

 be 24 inches ; and that the amount of action yielded there is 

 (as under some conditions is the fact,) about three times less 

 than that obtained at the first or standard position. Then by 

 substituting larger copper plates in succession in the place of 

 the small one, let it be determined by what size the amount 

 becomes three times greater, or exactly equal to that given 

 by the small plate at the first distance of ^ of an inch. 



132. But it is not yet proved that any addition whatever to 

 the size of the copper plate, at the supposed position of 24 inch- 

 es, will give an amount of action three times greater, or an 

 amount equal to that required. 



133. Before proceeding by an appeal to experiment to de- 

 termine this point, it might be presumed that each successive 

 addition to the size of the copper plate, whether at 24< inches 

 distance, or at whatever other position the trial might be made, 



