136 Chemico- Galvanic Olservafhm. 



the tincture of althea, and made it give with the prussiate 

 of potash a white precipitate, which in a few minutes, and" 

 in the contact of the air, assumed a superb blue colour. We 

 may conclude from this, that the iron in this salt is at the 

 minimum of oxidation, and that, consequently, the first com- 

 position formed is simple muriate, and not oxygenated mu- 

 riate, as Pacchiani supposed. There was no sensible quan- 

 tity of crust upon the metallic wire, and scarcely did the 

 surface of the negative wire assume the slightest tint of 

 black ; but it rendered the water into which it was plunged 

 strongly alkaline. 



This experiment was repeated with iron wires of a 

 quarter of a line in diameter, submitted for twenty hours 

 to the action of a strong pile. A certain quantity of oxide 

 of iron was seen filtering through the two membranous folds 

 which closed the tube at bottom, and a considerable quantity 

 of a deposit of the colour of ochre appeared at the bottom 

 of the water of the recipient common to both tubes : this 

 precipitate had all- the characters of a hydrogenaled oxide of 

 iron. A portion of this deposit, in contact with the parch- 

 ment which formed the negative tube, was decomposed, and 

 had passed to the deep black. The water of the common 

 recipient was neither acid nor alkaline. 



The author proceeds afterwards to the examination of the 

 changes which happened to the two iron wires attached on 

 one part to the poles of the pile, and plunging upon the 

 other side in the water of a common recipient. Here, in 

 the same manner, no. sensible production of gas was ob- 

 served on the positive side, while it was very abundant on 

 the negative side. The water of the recipient soon became 

 yellow; which proved that the iron was there in a particular 

 state of combination. 



Upon the positive side, besides the portion of muriate of 

 iron which was dissolved in water, there was a very abun- 

 dant oxide of this metal visibly precipitated, which was soon 

 hvdrogenated. It assumed a yellow colour and a flaky ap- 

 pearance; it was insipid, and insoluble in water. When col- 

 lected upon white blotting-paper, this precipitate assumed a 

 deep red colour. On exposure to a gentle heat, the colour 



changed 



