138 Galvanic Batteries. 



cuit, completed by a coil surrounding a bar of iron, or rather a 

 bundle of iron wires. As soon as the primal action had sub- 

 sided, the plate was removed and immediately reimmersed. 

 The primal action was by no means as intense, nor of as 

 long duration as when the plate was first immersed. It occur- 

 red to me that there was something due in this case to the dry- 

 ness of the plate. To ascertain this point, the immersed plate 

 was withdrawn, and the second plate, which was entirely dry^ 

 was immediately substituted ; the primal action was as intense, 

 and of as long continuance as with the first plate when first im- 

 mersed. That any new state of the liquid, induced by repose, is 

 not essential to the full action of a reimmersed plate, is proved by 

 this last experiment, viz. the introduction of a dry plate immedi- 

 ately after the withdrawal of an immersed plate. The plate was 

 then removed from the liquid and left standing over the battery, 

 while the other was dried by the fire. When this last was en- 

 tirely dried, the two plates were immersed in succession, with 

 the same difference in the results as before ; the dry plate afford- 

 ing a more intense and lasting primal action than the wet plate, 

 which had remained out of the battery about the same length of 

 time. The experiment was then varied in every possible way, 

 but always with the same difference in favor of the dry plate. 



The following experiment is still more striking, more especially 

 as the galvanic and chemical actions are not recognized in the 

 amalgamated zinc battery, until the plates are joined by a good 

 conductor. The two plates were thoroughly dried by a fire, and 

 one of them then immersed and suffered so to remain about the 

 same length of time as the primal action had usually continued. 

 The action of the battery was then examined, and was found to 

 be much below that of its primal impulse, and after the first 

 junction of the poles, immediately subsided to the low standard. 

 Evincing no more activity than such accumulation as would be 

 due to the disjunction of the poles when the battery had been in 

 use for a considerable length of time. The other dry plate was 

 then immersed, and the primal impulse, on immediate examina- 

 tion, was found to be intense and lasting as in prior experiments. 



From frequent observations, I am inclined to think, that chem- 

 ical action upon the zinc of the amalgam is somewhat promoted 

 by the presence of the copper plate, although the two plates are 

 not in metallic contact. The above experiments, repeated many 



