44 Laws of the Elementary Voltaic Battery. 



riable plate increased to twice the surface of the other. With this 

 view two new plates, similar to the former were prepared. Two 

 inches of one and variable proportions of the other were plunged and 

 between each set of immersions an interval of five minutes was al- 

 lowed. 



Copper, 2. 



z. 2. 



69° 



69 



69 



69 



Zinc, 2. 



From an inspection of the first four columns, namely, when the 

 copper is constant and the zinc variable, it appears although contra- 

 ry to the former observations, (2.) that the deflexion slowly augments 

 as the zinc surface is increased. This was not observed to occur in 

 any previous or subsequent experiments made under similar circum- 

 stances, it being found that with an increase of zinc surface, the de- 

 flexion diminished or else remained nearly stationary. We are in- 

 clined to attribute the discrepancy in this single instance to some pe- 

 culiarity in the surface of zinc plate, having obtained it from a difl^er- 

 ent mass. 



II. Experiments shewing the distinction between the first moment- 

 ary, and subsequent more permanent deflections. 



6. It will be remarked that in the experiments hitherto recorded, 

 no observation of the needle was made until the plates had been ex- 

 posed one minute to the solution. The momentary effects, measur- 

 ed on the instant of immersion, would of course have been much great- 

 er. We were anxious to observe the relation of the momentary and 

 permanent deflections, as also the influence upon both of these, pro- 

 duced by various intervals between immersion, and various periods 

 of exposure to the solution. In most of the experiments hitherto 

 performed by others on the elementary battery, attention has not 

 been directed to separating the momentary from the permanent ef- 

 fects, nor indeed to estimate the momentary effects themselves with 



