J TO On EJsSr'iclty excited hy the Cental of ConJui^ors. 



in the form of very thin dilks, placed one upon the other, or 

 fupported at very fniall dillartces by intervals, into which, as 

 appears, fome liquor flows. But we cannot fuppofe that any 

 of thefe laminae are of an insulating nature, like glafs, refin, 

 filk, &c. and ftill lefe that they can either become electric 

 fey friftion, or be difpofed and charged in the fame manner 

 as the fmall Franklinian plates or fmali clecrtrophores; nor 

 even that they are fufticienlly bad condu/.lors to perfonn the 

 office of a good and durable condenfer, as Mr. Nicholfon has 

 fuppofcd. The hypothelis of this learned and laborious phi- 

 lofopher, by which he makes of each pair of thefe pellicles, 

 which he compares to leaves of talc, as many fmall eli'£lro- 

 fhores or condenfers, is indeed very ingenious, and is, per- 

 haps, the beft theory that has &een devifed to explain the 

 phenomena of the torpedo, adhering to the hitherto known 

 principles and laws of eleftricity. For, belides that the me- 

 -chanifm, by which, eveiy time that the fifli intended to give 

 a fliock, the refpective feparation of the plates of the whole 

 or a great number of thefe eleftrophores or condenfers ought 

 to be effefted all at once, and ought to eftablilh on the on^ 

 hand a communicaition between themfelves of all the plates 

 fAt£u\?iK:d pqfttivtlj, and on the other a communication be- 

 tween all thofe eletftrified nfgativ-elj, as Mr. Nicholfon fup- 

 pofes — beiiues, that this very complex mechanifm appear* 

 too dilTicult, and little agreeable to nature ; — and befides, that 

 the fuppoiition of an electric charge originally imprefled, and 

 fo durable in thefe pellicl'js performing the office of electro- 

 phorcs, is altogether gratuitous, — fuch a bypothefis falls en- 

 tirely, fince tiiefe pellic'es of the organ of the torpedo are 

 not, aud cannot be, in aay manner infulating or fufceptible 

 of a real eleftric charge, and much lefs capable of retaining 

 it. Every animai fublhraee, as long as it is frefli, furrounded 

 with juices, and more or lefs facculent of ilfclf, is a very 

 good conduftor. I fay more, inftead of being aa cohib-ent as 

 refins or talc, to leaves of which Mr, Nicholfon has com- 

 pared the pellicles in queftion, there is not, as I have alTured 

 myfclf, any living or frelh animal fubftance which is not a 

 better J<ferent than water, except only greafe and fome oily 

 humours. But neither thefe humours aor greafe, efpe- 

 7 ciaJly 



