134 Chemico- Galvanic Ohservatidnt. 



paper. That upon the positive side was also separated ; it 

 was black, less abundant, and adhering to the metallic wire^ 

 although one part had formed a black deposit above. 



The gray deposit of the negative pole was dried in the air. 

 The colour brightened in proportion as the drying advanced; 

 and this powder, slightly mbbed with the burnishing stick, 

 assumed the brilliant and white colour of the metal, and ap- 

 peared to be nothing else than very pure silver. It was then 

 a true combination of water and silver, as well as a hydrure 

 of this metal, — a singular combination, and unknown until 

 the present day; "because," adds the author, "the metallic 

 hydrates, examined by Proust with so much exactitude, re- 

 sult from the combination of the water with the metal in the 

 state of oxide, and not in that of regulus." 



The crust and the black deposit coming from the positive 

 pole were recognised to be hydrogenated silver. It black- 

 ened paper, linen, and the ringers ; it was a little soluble in 

 ammonia, and insoluble in the muriatic acid. It was not 

 revived by the action of the solar rays, but very well by heat, 

 en allowing the escape of hydrogen gas. 



When the two silver wires in the two separate tubes were 

 submitted to the Galvanic action, very little hydrogenated 

 silver only appeared upon the negative wire in the form of 

 black crust. There was a little upon the point in a flake. 



(c) Copper and Oxide of Copper oxygeiiated ly the Galvanic 

 Action, 



Two wires of very fine copper were galvanized for several 

 hours, communicating with the two poles of the pile, and 

 inserted in two separate tubes full of water. A black crust 

 was seen upon the negative wire, which was easily separated 

 from the mefal which it covered, and which, when folded 

 in paper, gave it a black tint ; the copper from which it had 

 been detached appeared of the utmost metallic brilliancy. 

 When the two wires were galvanized in a single recipient, 

 the matter decomposed upon the negative wire showed itself 

 in the water of the vessel in the form of a small and very 

 black arborization, in alto relievo, contrary from that upon 

 the gold wire. Gas was liberated round the two wires. The 



black 



