AdiUthnal Notes. 393 



even when the points tenninnte in two diflcMont portions of water, 

 as was discovered by Mr. Davy, provided that the glasses are 

 united by a conductor which is not oxydable. 



To exphiin the operation ciirried on in tlie body of the pile 

 itself. Dr. Bostock says — 



In the construction of the pile there arc two points which are 

 essential to its action; viz. 1. That the electric fluid be disen- 

 gaged ; and, 2. That it be confined and carried forw nrd in one 

 direction, so as to be concentrated in the end of the apparatus. 

 Tlie first object is evidently attained by the oxydation of the zinc, 

 or otlicr oxydable body employed. If both sides of the zinc were 

 oxydated, the electric fluid would, indeed, be liberated, but it 

 would be immediately dispersed, and its e/lects could not be ob- 

 served. As soon, however, as the electric matter is CAulved, it is 

 immediately atti'acted by the hydrogen ; v.hich is, at the same 

 time, necessarily generated in the fluid vshich oxydate.s the metal j 

 and it is by tliis means conveyed across the water to the silver 

 plate, when two metals are used, or, in other cases, simply to the 

 opposite surface of the oxydating substance. The electric fluid 

 then enters the silver plate, and, instantly passing on to the con- 

 tiguous zinc plate, arrives at a second oxydating surface. I'he 

 same series of e^'eTlts that have been described is here repeated, ex- 

 cept tliat the electric fluid being in some degree accumulated in 

 the metallic plate, is disengaged by the second oxydating surface 

 in larger quantit}', and in a more concentrated state than before. 

 By pursuing the same train of operations, it is easy to see how the 

 dectric matter will continue to be aceumulated in each successive 

 pair of plates, until, by sufficient repetition, it may be made 

 to exists in the zinc end of the pile, in auy assigned degree oi 

 force. 



The analogy Ijetween Galvanic phenomena and mnny circum- 

 stances connected with muscular action, and other processes of 

 vitality, began, several }'ears ago, to make an impression on tlic 

 minds of many who engaged in tlie pursuit of tliis science. TJie 

 appearance of Galvanic action in living animals, such as the 7ar- 

 pedo, kc, was found strongly to corfirm tliis inipression. Or- 

 ganised beings contain all the substances necessary for the formation 

 of Galvanic arrangements ; and chetuical changes are conlinually 

 going on in different parts of the living body, which are probably 

 connected w itli variations in their states of electricity. I'licse cir- 

 ,<Lwnstaaces^ together \s ilh the origiiial Galvanic fact of the j)ro- 



