180 



The latter lefs 

 probable. 



The oxidation 

 contraidids the 

 hypothefis of 

 two eleftrie 

 bodies* 



Variation of Dr. 

 Afh's exptri- 

 xnent. 



When a long 

 copper wire was 

 conneded at the 

 end with zinc 

 (under weak 

 iiUph. acid) 

 hidrogen was 

 earlier given out 



GALVANIC POW£R. 



They tell us of two kinds of eledtricity coming from thegaf-* 

 vanic apparatus one from the zinc end, the other from th« 

 copper end: the former being pofitive, the latter negative. 



Two diftindl fluids moving in contrary dire£iions could not 

 pofliblyexift in the galvanic trough; by reafon of that fluid 

 proceeding from the zinc meeting that coming from the cop- 

 per in each of the cells, and confequently eftabJifl^ing a con- 

 flant equilibrium, without producing any effeft. When lh« 

 decompofilion of water is only taking place in one velfel (ad- 

 mitting the above objedion to be of no weight) the phenomena 

 admit of an eafy explanation by this hypothecs; but when two 

 veflels are ufed connected by a wire arch, it cannot in any 

 (hape be adequate; for as we have in each veflel both oxigen 

 and hidrogen gafes, there muft alfo be both pofitive and nega- 

 tive eledricity ; thefe two contrary fluids would of courfe have 

 to meet each other in the connecting arch, and according to 

 another part of this theory form fenlible heat *. 



The pofitive wire, if a bafe metal is always oxidated; this 

 effect is known to be facilitated by the electrical agency. Ac- 

 cording to the principles in queftion, it would be retarded by 

 the power of affinity exifting between water and pofitive elec- 

 tricity. When the wires of a galvanic apparatus are brought 

 into a metallic folulion, no hidrogen is given out at the nega- 

 tive wire, but the metallic oxide is reduced. Now if metal- 

 lic oxides be compofed of water and the metal, the negative 

 eleftricity would combine with the water, and hidrogen ga» 

 would be evolved — the very reverfe of the fa6l. 



My reafon for being thus particular in the examination of 

 the hypothefis of Mr. Richter and Dr, Gibbs, is to prepare 

 the mind of the reader for fome experiments which I think 

 will contribute to the firmnefs of the hypothefis, which fup- 

 pofes water to be a compound, and that the hydrogen is car- 

 ried from the pofitive to the negative wire by the electricity. 



The well-known experiment of Dr. Ath (with the plate of 

 zinc and fiilver in a dilute fulphuric acid) I had occafion to 

 vary in the following manner. I took a copper wire abou^ 

 eighteen inches long, and bent it in the middle fo as to form 



* They are of opinion that thefe two fluids combined form calo- 

 ric. They alfo hold with Dr. Prieftly that what are now termed 

 metallic oxides are the refpe^ive metals combined with water. 



tw9 



