EXAMINATION OF VOLTAY EXPERIMENTS, &C. 283 



pofitive than when the copper was infulated. For whatever The effect is 



quantity of electric fluid may be drawn out of the copper by the ftr °nger when 



,,.,,. . ~. • i ,• , the zinc alone is 



zinc, is recovered by its being in connection with continued i n f u i ated an< j 

 conductors ; whereas, if it had been repelled from the copper le <s when the 

 into the zinc, it mud be flronger when infulated, becaufe when jn/Jated"" 6 1S 

 infulated, the copper has no other body but the zinc to receive hence the zinc 

 that which it repels from it ; and when not infulated, every ^^ rred t0 

 other conductor with which it is connected takes a part in pro- 

 portion to their conducting property. As the zinc difc is found 

 to be much ftronger when the copper difc is not infulated, I 

 conclude that zinc has the property of attracting the electric 

 fluid out of copper when they are in contact. 



In regard to the fecond experiment, where the zinc is found ? n €x P. t * **• tJle 

 to be much more flrongly pofitive than in the firft, is clear from z ; nc } ncrea f es 

 what I have already faid, I. e. becaufe the copper difc is not tne effect, 

 infulated, but is free to act as their mutual action upon each 

 other may require. 



In the third experiment, in which no effect mould follow Expt. III. The 

 (according to Sig. Volta), the zinc was found to be as flrongly J^.' 5 ^ a n | u ^ e 

 electrified as in the Iaft experiment. Neither the zinc nor the the iefpecYive 

 copper being completely infulated, they are at liberty to a6l^ te f * oncon ' aa » 

 upon each other as their mutual contact directs ; the zinc atingly. 

 liberty to attract and the copper to give, which is in no wife 

 repugnant to the old laws of electricity. 



How Sig. Volta could be led to fuch erroneous conclufions Sig. Volta fup- 

 is not eafy to underfiand, unlefs he was deceived by the con- P ofed to have 



y J been deceived by 



denfers he made ufe of. '« To render that feeble electricity his varnijhedcon- 

 '* fenfible and manifefr, he recommends flat metallic plates C 0'^ e "f eru 

 " vered with a flight layer of fealing wax or lac varnifh," which 

 I was not a little lurprifed at, becaufe I have always found 

 fuch condenfers very equivocal in their refults, and fliew differ- 

 ent figns without any variation or obvious caufe, or at leafl 

 fuch as I was unable to detect. They are more eafily excited 

 by a negative power than by a pofitive one, and retainit much 

 more tenacioufly ; and hence, when they happen by any means 

 to be flrongly electrified by a negative power, it is almoit im- 

 poffible to difcharge them of it, fo as to be fit to proceed on 

 immediately with experiments that require nice invefligation. 



Since the invention of the galvanic inftrument, various elec- Mr. John Read's 

 trometers, condenfers, doublers, multipliers, &c. &c. have theco'nSnfe^ 

 been ufed to invefiigate its electrical properties, all of which 



appear 



