Account cffime Galvanic Comhittatiam, 343 



Wlien zinc is employed, on account of its rapid oxidation in water containing atmof- 

 pheric air, three cloths fliould be ufed ; the firfl moiftened in weak folutlon of fulphuret 

 of pot-afli, (which is poflefled of no power of action upon zinc, and which prevents it from 

 afting upon the water;) the fecond moiftened in a folution of fulphate of pot-afli, of 

 greater fpecific gravity than the folution of fulphuret } and the third wetted in an oxidating 

 fluid fpecifically heavier than either of the folutions. In this cafe, if the order be as fol- 

 lows, zinc, oxidating folution, folution of fulphate of pot-afh, folution of fulphuret of 

 pot-afh, very little mixture of the fluids^ or chemical a£lion between them, will take place : 

 and an alternation of twelve feries of this kind, forms a battery capable of producing fen- 

 Cble effedts. 



III. The fecond clafs of Galvanic combinations with fingle plates is formed, when 

 plates, or arcs, compofed. of a metallic fubftance capable of adling upon fulphurated hi- 

 drogen, or upon fulphurets diflblved in water, are formed into feries, with portions of a 

 folution of fulphuret of pot-afli, and water, in fuch a manner that one fide of every plate, 

 or arc, is in conta£i with water, whilft the oppofite fide is adted on by the folution of 

 fulphuret. Under thefe circumftances, when the alternation is regular, and the number 

 of feries fufBciently great. Galvanic power is evolved ; and water, placed in the circuit 

 with filver wires, is afled on ; oxide being depofited on the wire connedtcd with the fide 

 of the plate undergoing chemical alteration, whilft hidrogen is evolved from the fide ia 

 conta£t with water. 



Silver, copper, and lead, are each capable of forming this combination. Plates made 

 from either of thofe metals, may be arranged with cloths, (moiftened, fome in water, and 

 others in folution of fulphuret of pot-afli,) in the following order, metal, cloth moiftened 

 in fulphuret of pot-afti, cloth moiftened in water, and fo on. 



Eight feries will produce feriCble effeftsj and the wire, from the top of the pile produces 

 oxide. 



Copper is more a£llve, in this clafs of batteries, than filver : and filver more a£tive than 

 lead. 



IV. The third and moft powerful clafs of Galvanic batteries, conftrufled with fluids and 

 fingle metals, is formed, when metallic fubftances oxidable in acids, and capable of a£lii% 

 on folutions of fulphurets, are connefted, as plates, with oxidating fluids and folutions of 

 fulphuret of pot-afti, in fuch a manner that the oppofite fides of every plate may be under- 

 going different chemical changes ; the mode of alternation being regular. 



The fame metals that aft in the fecond clafs, niay be ufed in the third clafs ; and the 

 order of their powers is fimilar. The pile may be erected in the fame manner as the pile 

 with zinc in the firft clafs ; the cloths moiftened in acid being feparated from thofe moift- 

 ened in folution of fulphuret, by a third cloth, foaked in folution of fulphate of pot-afli. 



Three plates of copper, or filver, arranged in this manner, in the juft order, produce 

 fenfible efi'efls j and twelve or thirteen feries are capable of giving weak (hocks, and of 

 lapidly producing gas and oxide in water ; the wire connefted with the oxidating end of 



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