f9n4 certain limit*, which apparently varied ucdordfinf t» 

 the btate of ine atmobphere as lo moi&iure: and it is 

 ^ worthy oi reiiMirk, thai tiie oaanoer in wtnch the pla'cies are se- 



parated mattimuy etiecti* the re^ulc o.^' thfe> »epa,ratioo. If 

 on«t be blid iilcmg the oih«r, iieith«r will evTuc* sign* ©f 

 '• electricity. The contact and separation ot tkvo' copper 



plates produced qo feens^ble t^tii^ct on the ^oid leaves. From 



I)ectitc«i these, and the experimentj ol Wilktt and (Epiuusi, I feel 

 5»te» of bodies ' /. , i 



Tet^dered ci\U myseli warranted m coneluding, that tiie ^lectncal 6tate» 



fereot by their ^ disbimilar metals, and other dissimilar bodies, a're 

 Thto.apj)iica- ^^ rendered different by the contact of theat: Ijodies witli 

 Wetorabiute q^^ another, but by their separation after contact*. I 

 '^ would also, from analogy, extend my conclusion tJo the aai- 



l»iite p*rticle» of dissimilar Wrid's^of matter ; aud woB^d^say, 

 that irhen in contact, as in composition, they possess thei^r 

 natural, or, as I have endeavoured to show, in similar elec» 

 trical states ; but that on their separation, as in deijom po- 

 sition, thej^ acquire electrical states different from whljt'they 

 bad while incontact, and cortseqliently different from theii* 

 natural electrical stales ; and that from snch change in the 

 electrical states of the constituents of a compound, in don- 

 sequence of separation, analogous to what takes' |)ldcfe in 

 fcspect to the voltaic plates, the one set of particlies'b<?comes 

 relatively to the Earth and surrounding bodies positive, thi 

 other set negative. 

 Stt position '^^^ experiments, to which I have jnst alluded, appear to 



•hattbemctal* me perfectly sufficient to point out the fallacy of the' ex- 

 inthegavYaaiCpjj^j^j-^^^^y^^^.|^ j^^,^^.^ generally received, of the excitfemeti^ 

 ibreKt states, of the galvanic pile; the whole of which rests on theassump- 

 c*ioB€ftB&f tion, that dissimilar metals, while in contact, aro'in different 

 electrical states, the one being relatively positive, th*- othe^ 

 negative; which has been shown to be perfectly untenable. 

 The following also 1 consider as additional and weighty ob- 

 jections to the hypothesis. 1: The voltaic pUitesdnly net 

 when applied to each other by esttensive surfaces.' Ih the 

 present roost improved galvanic troughs, the mi^talaha^e'c^Wi 

 nected together by comparatively few^ points, an<^*the cbh4 

 trivance has not only rendered the apparatils more conve* 

 }ik\ ent for U8e> but also' morei powerf u 1 . 2, Volti'fc plates at^ 



..'•.■ . / ,,■. •' . • ^ . •'- -nft 



• An account of the experiments of Wi'ke and of CKpinus will be found 

 Mi Dr. Priestley's Histiwry of .jfcleciriclty, 



only 



