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February 2, 1837. 

 FRANCIS BAILY, Esq., V\P. and Treasurer, in the Chair. 



" Observations on the Electro-chemical Influence of long-con- 

 tinued Electric Currents of Low Tension." By G. Golding Bird, 

 Esq., F.L.S., F.G.S., Lecturer on Experimental Philosophy at Guy's 

 Hospital. Communicated by Thomas Bell, Esq., F.R S. 



The author, after observing that the brilliant discoveries in electro- 

 chemistry obtained by Sir Humphry Davy were effected by the employ- 

 ment of voltaic curren ts of high in tensity, elicited by means of large bat- 

 teries, adverts to the labours of M.Becquerel, to whom we are indebted 

 for the knowledge of the chemical agency of feeble currents in re- 

 ducing several refractory oxides to the metallic state : and also to 

 those of Dr. E. Davy, Bucholtz, and Professor Faraday in effecting 

 decompositions of other substances by similar means. In prosecuting 

 this branch of inquiry, the author employed an apparatus analogous 

 to that of Professor Daniell, for obtaining an equal and continuous 

 current of low intensity from a single pair of plates : the metallic so- 

 lution, in which a copper-plate was immersed, being contained in a 

 glass tube, closed at the bottom by a diaphragm of plaster of Paris, 

 and itself plunged in a weak solution of brine contained in a larger 

 vessel, in which a plate of zinc was immersed ; and a communication 

 being established between the two metallic plates by connecting wires. 

 By the feeble, but continuous current thus elicited, sulphate of copper 

 is found to be slowly decomposed, affording beautiful crystals of me- 

 tallic copper. Iron, tin, zinc, bismuth, antimony, lead, and silver 

 may, in like manner, be reduced, by a similar and slightly modified 

 process ; in general appearing with metallic lustre, and in a crystal- 

 line form, and presenting a remarkable contrast in their appearance 

 to the irregular, soft, and spongy masses obtained from the same so- 

 lutions by means of large batteries. The crystals of copper rival in 

 hardness and malleability the finest specimens of native copper, which 

 they much resemble in appearance. The crystallization of bismuth, 

 lead, and silver, by this process, is very beautiful ; that of bismuth 

 being lamellar, of a lustre approaching to that of iron, but with the 

 reddish tint peculiar to the former metal. Silver may thus be pro- 

 cured of the whiteness of snow, and usually in the form of needles. 

 Some metals, such as nickel, which, when acted on by currents from 

 large batteries, are deposited from their solutions as oxides only, are 

 obtained, by means of the apparatus used by the author, in a brilliant 

 metallic form. He farther found that he could in this way reduce even 

 the more refractory metallic oxides, such as silica, which resist the 

 action of powerful batteries, and which M. Becquerel could only ob- 

 tain in alloy with iron. By a slight modification of the apparatus he 

 was enabled to form amalgams both of potassium and of sodium with 

 mercury, by the decomposition of solutions of chlorides of those bases ; 

 and in like manner ammonium was easily reduced, when in contact 

 with mercury, bv the influence of a feeble voltaic current. In this last 



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