132 Ohemico- Galvanic Observations. 



water becomes alkaline. The author supposed that this al- 

 kali might probably dissolve the hydrat of gold as it was 

 formed, and thus hinder it from appearing upon this metal; 

 but the substance not being soluble in pui^ soda, he aban- 

 doned the idea. 



He made a gold wire descend from each of the poles'of 

 the pile into the same tube, which contained a solution of 

 soda diluted in water. After a few hours Galvanic action 

 the two wires were coated with a black crust, so slender that 

 it could not be collected in a sufficient quantity for examina- 

 tion. The author thought that it was on one side as well as 

 the other hydrogenated gold. 



This compound loses its water and its hydrogen by the 

 action of oxygen at its formation. The author proved it by 

 the following curious experiment : 



He took a gold wire covered with this substance, obtained 

 in pure water galvanized with the two metals, as has been 

 indicated, and he made this wire pass from the negative to 

 the positive pole. He even adapted to the negative pole the 

 gold wire which had belonged to the positive pole, always 

 in the same water. The black substance was then seen to 

 diminish in volume by little and little, as if contracting it- 

 self upon the wire, which by degrees resumed its colour and 

 brilliancy, while the opposite wire was covered, in its turn, 

 with hydruret of gold. This apparent metamorphosis was 

 performed in a few minutes. 



This hydruret of hydrogenated gold is a conductor of Gal- 

 vanism ; because the metallic wires, although completely 

 covered with this substance, speedily decompose water as 

 soon as they are put in communication with the pile. 



The quickness of this union of hydrogen to gold by means 

 of Galvanism, and the singularity of this production, made 

 the author suppose that it was upon this new body, very 

 different from pure gold, that the supposed polarity of pieces 

 of cold observed by Ritter depends, and which Brugnatelli 

 has shown not to exist, except in such of these pieces as 

 were in communication with the negative pole. These 

 pieces, when left for some time in the Galvanic circuit, and 



lodged 



