378 GALVANIC ELECTRICITY. 



Becquerel, and Faraday, the question may now 

 be regarded as decided. Davy himself observes 

 in the Bakerian Lecture, read before the Royal 

 Society on the 8th of June 1826, that there is 

 no instance of electro-motion, (by which he meant 

 galvanic action,) without chemical decomposi- 

 tion. He also states, that when oxidizing liquids 

 are employed in maintaining the action of the 

 battery, the more oxidable metal always afforded 

 positive electricity in relation to a less oxidable 

 one that potassium, which is the most oxidable 

 of all the metals, is positive in relation to all 

 others; and so of its amalgams that barium 

 and its amalgams are positive in relation to an 

 amalgam of zinc, which is positive in relation 

 to pure zinc, zinc to cadmium, the latter to tin, 

 tin to iron, and iron to bismuth. 



Corresponding with the above results are 

 those of Delarive, who found that the direction 

 of a galvanic current is not determined by me- 

 tallic contact, nor by the nature of the metals 

 relatively to each other, but by their chemical 

 relation to the exciting liquid that of two metals 

 composing a voltaic circle, the one which is most 

 energetically attacked is positive with respect 

 to the other. Thus, when tin and copper are 

 placed in acid solutions, the former, which is 

 most actively corroded, gives a positive current 

 through the liquid to the copper: but if put into 

 a solution of ammonia, which acts most on the 



