308 Kirwanian Soviely of Dublin. 



KinWAJXlAiJ SOCIETY OF DUBLIN. 



The reading of the " Essay on the Origin, Progress, and pre- 

 sent State of Gahanism, with Observations on the Inadequacy 

 of the Hypotheses, Sec. &cc." by M. Donovan, Esq. Secretary, 

 Avas continued. 



April 5. Examination of the hypothesis ofVolta. — An arranged 

 statement of this philosopher's opinions was first given, with the 

 fundamental experiments on whicli these opinions v.ere grounded. 

 The principle of the disturbance of the electric equilibrium was 

 first discussed. It was conceived that, for reasons assigned, this 

 principle is rejiugnant to the known laws of electricity ; that it 

 is not supported by any of Volta's experiments but one, and that 

 this lies under a two-foid objection : first, it admits of a different 

 explanation ; and next, it has not succeeded in the hands cf 

 others. The structure of the pile apparently affords a proof 

 that contact produces electricity : but exjieriments were adduced, 

 which appeared to prove that during the contact of the platen 

 thei-e is no electrical appearance, tl-.at these are produced be- 

 fore the contact takes place, and after it is broken ; or, in other 

 words, that the evolution of electricity happens when the plates 

 are at a minute distance asunder. The experiments of Vv'ilson 

 proved that during contact the electrometer is not affected : 

 new experiments were detailed, showing that metallic electricity 

 obeys the common law, and that contact of conductors instead 

 of disturbmg restores the equilibrium. The effects of placing a 

 metal between two others of a similar kind were next examined. 

 Volta conceives that two elcct:ric currents are excited in oppo- 

 site directions, which therefore destroy each other : hence, in 

 such a situation of the three metals, the equilibrium is main- 

 tained, and accordingly the electrometer is not affected. The 

 iuithor showed, that the three metallic ])ieces thus arranged 

 display phenomena which do not belong to these metals under 

 ordinary circumstances ; and, therefore, since the electricity is 

 in a state of repose, m hat is the cause of the effects. A great 

 variety of other considerations were adduced, from the whole of 

 which the precise f^tate of the question concerning the agency 

 of contact was concluded to be aa follows. The principle is op- 

 posed by the laws of electricity : it is founded on experiments 

 which, admit of a different explanation, which were made with 

 a doubtful apparatus, which did not afford similar results when 

 iusttumenls less liable to fallacy were employed, but in some 

 cases entirely opjjositc : it is proved that contact instead of dis- 

 turbing restores the equilibrium ; and that some phenomena of 

 contact are inexplicable by this principle, whether the electricity 

 be in action or at rest. 



Wavinc 



