42 Laws of the Elementary Voltaic Battery. 



In the experiment where the zinc was dipped to li in. it will be 

 remarked that the numbers are greatly higher than in the preceding. 

 This arose from our having allowed the plates to remain out of the 

 solution for about an hour. When compared with the first column, 

 when the plates were fresh, and therefore nearly in the same condi- 

 tion, although the zinc was then only ^ inch, we find the deflection 

 to be no greater. 



The above results show that no increase of effect is produced by 

 an increase of the zinc surface exposed to the acid, the copper sur- 

 face remaining constant. Indeed, the whole tenor of the experi- 

 ments shews that in proportion as the zinc surface increases, the effect 

 diminishes. 



2. With the view of bringing these two extremes together, the two 

 following experiments were performed ; the zinc being well dried be- 

 fore each immersion. 



Copper as before 2i in., zinc dipped to 

 z. 1 in. z. 21 in. 



1. 27° - "^181° 



2. 251 _ 18 



3. 23" - 15 



3. In order to vary the experiments the slips were not removed 

 from the liquid, but were slid through the slits which hold them, to 

 each succeeding depth required. 



Copper constant at 4 inches. 

 J in. z. 1 in. z. 1 J in. z. 2 in. z. 2J in. z. 3 in. z. 3^ in. z. 4 in. z. 



1. 173° - 88° - 86° - 86° - 86° - 86° - 84° - 81° 



2. 147 - 85 - 84 - 83j - 85 - 84 - 82 - 80 



3. 114 - 84 - 84 - 83 - 82 - 84 - 81 - 80 



In this experiment although less strikingly than in that previously 

 described, a tendency to diminished action is observable as the zinc 

 surface increases. 



This was done with the view of ascertaining whether the declining action was in any 

 degree owing to the gradual weakening of the solution. 



