Potta on Animal EleSlricify, 6^ 



Tnis furprifing experiment I generally make in fuch a man- 

 her, that, inftead of the piece of metal, I employ a eup or 

 fpoon filled with water, arid then caufe the perfon who holds 

 the perfeftly dry and pure ftick df tin to touch with that 

 ftick fometimes the; perfeftly dnf fides of the fpoon or cup, 

 and fometimes the water contained in them. It is wonder- 

 ful to fee, that as by the latte^ method the violent agitation 

 of the frog never ceales, the firft method, which correfponds 

 with fig. 12, does not produce the leaft irritatioft; unlefs by 

 accident there be a fmall drop of watefj tfr a thin ftratum of 

 moifturcj at the place cjf contaft, by which the cafe repre- 

 fented fig. 14 would be reftored. This may ferve to 

 Ihew with what care and attention the experiment muft be. 

 inade, in order to guard againft error or deception, which 

 might fo eafily arifc, and every where exhibit anomalies. 



When I introduce water or any other moift body, great 

 trr fmall, not merely between one pair of metallic pieces A, 

 Z, as fig. 14, but between tvi'o pairs, as reprefented fig. 18, 

 each piece of metal is between like moift conduftors, and 

 by thefe means all the a6lions are again rendered contrary or 

 brought into equilibrium ; or, according to the other mode 

 of viewing the matter, there is no longer any atlion, for want 

 of the mutual contact of two ditferent metals, which, as we 

 have feen, is certainly neceflkry to excite an eleftric cur- 

 rent; and it is always found that the frog experiences na 

 agitation. 



I fliall riot enlarge farther on thefe combinations, which 

 may be varied ad infinitum with a greater number of me- 

 tallic pieces, and by which one may be enabled to forctel the 

 phenomena which, according t6 my principles, will always 

 be found to take place. It will be fufficierit, for the prefcnt, 

 to draw this conclulion, that in a circle confifting merely 

 ftf two condu(ilors, however diffef'cnt they may be, their 

 mutual contadt can produce no eleftric ftream fufticient tw 

 excite fcndbility or mufiular mo\eiucnl; and that, on the 

 contrary, iliis effe6t iiifillibly follows as often as the chain it 



Vol. 1Y. F formed 



