"gtfi , Galvanic Powers of different MetalH 



the other combinations of iron, were worthy of notice. With gold, the ruft was very 

 red and very bright. The part of the iron in contaiSt with the mercury retained its' 

 metallic luftre. 



Experiment 3.>— Lead, combined with gold — filver— Copper — tin — mercury. 



In thefe combinations the operations of the galvanic apparatus were very feeble. The 

 lead formed the cxydating bafe. When combined with gold or filver, oxide was depofited 

 from the wire conne£ted with the lead, and the other bafe produced fome gas. With 

 copper, the oxide was more fparingly formed, and very minute bubbles of air appeared at 

 the extremity of the wire connefted with the copper. With tin, only a fmall cloud ap- 

 peared at the extremity of the wire connefted with the lead, and no gas was formed by 

 the oppofite wire. With mercury, 20 pieces of lead afted very feebly ; fcarce any effett 

 was perceptible, a fmall fpeck of a cloud was vifible at the extremity of the wire conne£led' 

 with the lead, and no gas at the oppofite wire : but from the caufticity which at firft was 

 perceptible, it appeared that thefe metals in greater quantities might be capable of a£ling. 

 The lead was, of courfe, much amalgamated by the mercury. 



Experiment 4.— Tin, combined with gold— filver — copper — mercury. 



Thefe combinations afted more feebly than any in the former experiments. The tin, 

 when any efFeft was apparent, was always the oxydating bafe, but it produced only a cloud 

 in the water in the glafs tube. With 44 pieces of gold (guineas) a fmall quantity of gas 

 appeared, but with filver, or copper, no gas was vifible at the extremities of the wires 

 connefted with thofe bafes, till the apparatus was increafed to 160 pairs of metallic plates- 

 With mercury, no effeft was produced, not even caufticity was perceptible, and the tin, 

 which was 20 circular pieces pf tin-foil, was foon amalgamated, and nearly diflblved by 

 the mercury. 



Experiment ;. — Copper, combined with gold — filver— mercury. 



In thefe combinations, no efFeft was vifible, excepting in the combination of 67 pairs of 

 copper and filver. The wire which was connefted with the copper, was furrounded with 

 fmall bubbles of air, and formed a cloud in the water, but the wire connected with the 

 filver bafe, produced no gas. With 56 guineas the copper (penny pieces that have been 

 always ufed) produced no oxyde and no gas, but when the apparatus was put together, a 

 cauftic fenfation was perceptible upon touching it with the tongue, and which feemed to 

 indicate a tendency to aft as a galvanic apparatus if the number of metallic plates had been 

 incrcafed. With mercury, 20 plates of copper produced no effefts whatever. 

 . Experiment ^.< — Silver, combined with gold. 



In this combination of 30 pairs of plates, no caufticity, and no effeft whatever, was 

 perceptible. 



Judging from the refults of former experiments, it was not thought neceffary to combine 

 either filver or gold with mercury, as no effeft could be expefted that was likely to com- 

 pcnfate for the certain amalgamation of thofe metals 5 but it would have been very de- 

 firablc to have extended thefe enquiries to the effefts which the other metallic fubftances 



combined 



