62 Chemico- Galvanic Observations. 



while their other extremities were inserted in the water of 

 the two separate tubes, produced the following effects : — there 

 ifrftSj as usual, a good deal of gas disengaged at first from the 

 negative side, without any sensible alteration in the metal, 

 although it was slightly blackened. On the positive side no 

 bubbles were perceived, but a good deal of white oxide wa» 

 formed, which made the water milky, and was partly pre- 

 cipitated. At the end of six hours of Galvanic action the 

 water was neither acidulated nor alkaline ; but in twelve! 

 hours it changed the blue tincture of althaea into a green. 



When the two stripes of tin were inserted in one vessel, 

 the water constantly became alkaline and of a milky colour 

 from th-j effects of the precipitate on the positive side. 



Upon substituting zinc in place of tin in two separate 

 tuhes, s;gns of alkalinity were very speedily obtained in the 

 water on the negative side \ but on the other side very weak 

 Signs only at the end of twenty-four hours. Both of the 

 stripes of zinc were equally covered with a blackish coatj 

 which the author supposed to be the hydrogenated metal. 



§ IN. 



Experiments uhich demonstrate that, in the Decompositiori 

 of Water produced ivith Gold Wires attached to the posi- 

 tive Side of the Pile, Muriatic Acid is not aluavs formedi 



The author galvanized nitric acid for twelve hours with a 

 gold wire attached to the positive pole of the pile. Oxygen 

 gas was continually liberated. The acid did not undergo 

 any perceptible change, and the gold was not dissolved, 

 which proves that aqua regia was not formed in the process. 

 Cruickshank, when galvanizing positively this same acid 

 with platina wires, and Davy with gold wires, did not pro- 

 duce any change upon it: but Vassalli-Eandi has maintained 

 that if this same acid is very much concentrated it is de- 

 composed by Galvanism. 



Upon treating in the same manner on the positive side 

 of the pile a solution of crystallized acetate of lead, the gold 

 wire became speedily black towards the highest part intro- 

 duced ; a little lower, a deep red ; and at last, citron. After 

 twenty-six hours continuance in the Galvanic circuit with- 

 out 



