end Agency of EleBricliy, ^&jf 



In dilute nitric acid, nitrous gas is formed, in the fame man- 

 ner, and under the fame circumftances, as the hydrogen gaa 

 in the former experiment. 



Exper.^. Experiments analogous to the former, and equally 

 fimple, may alfo be made with many metallic fulutions. If, 

 for inftance, the foiution contains copper, it will be precipi- 

 tated by a piece of iron, and appear on its furface. Upon 

 filver mcrelv immerfed in the fame foiution, no fuch eflcft iii 

 produced ; but as foon as the two metals are brought into 

 contaft, the lilver receives a coating of copper. 



In the explanation of ihefe experiments, it is neceflary to 

 advert to a point eftabliflied by means of the elediric pile. 



We know that when water is placed in a circuit of coo- 

 duAors of eleiftricity, between the two extremities of a pile, 

 if the power is fufiuient to oxidate one of the wires of com- 

 munication, the wire connected with, tbe oppolite extremity 

 affords liydrogen gas. 



Since the extrication of hydrogen, in this iiidance, is feen 

 to depend on eledlricity, it is probable that, in other iii- 

 ftaiK;es, electricity may be alfo recj^uitite for it* converlioa 

 into gas. It would appear, therefore, that in the foiution of 

 a metal, eleftricity is evolved during the action of the acid, 

 upon it; and that the formation of hydrogen gas, even in that 

 cafe, depends on a traafition of elcdlricity between the fluid 

 and the metal. 



We fee, moreover, in the firft cxp<.TiiTient, that the zinc, 

 without contaftof any other metal, has the power of deconi- 

 pofing water; autl we can have no reafon to fnppofe that the 

 tonta<:>^ of the filver prodiH;es any new power, but that it 

 ferves merely as a conduob)r of eleftricity, and thereby occa- 

 iions the formation of hydroeen gas. 



In the third experiment alfo, the iron by itfelf has-tiie 

 power of precipitating copper by means, I pre("um«, of elec- 

 tricity evolved during its foiution ; aiui here hkewife the 

 filver, by conducting that clctilricity, acquires the power of 

 precipitating the copper in its metallic (late. 



The explanalicni here given receives additional conSmia- 

 tion from comparative experiments which I have made with 

 common electricity ; for it will be Iccn that the fame traiisier 

 of fheniical power, and the fani'" apjiiu'ent reverfion of the 

 ufual order of chcujical affiuilied in the i)reci|)Hati()u of copper 

 by tilver, may be efferted by a common electrical machine. 



The machuie with which the following expernnenti v^-ere 

 couductcii, eoulilts of a evlinder 7 inchea in diameter, wiiU 

 a U)ndu(^tor ou fach tide 16 inclic^ long and 3^ inches dia- 



luettr. 



