Chemico- Galvanic Observations. 135 



black substance of this second experiment was easily col- 

 lected, and was discovered to be hydrogenated copper. It 

 was insipid, and insoluble in water and ammonia; soluble 

 in the nitric acid, which was not coloured blue, perhaps 

 because the metal was not in sufficient quantity. The so- 

 lution took place without effervescence. 



The copper wire galvanized positively in water, in a sepa- 

 rate tube, or in the same vessel where the negative galvani- 

 zation takes place, is covered with oxide, which soon con- 

 verts itself into hydrogenated green oxide, passing to the 

 brown when dried by fire. The wire was coated with a crust 

 of a steel colour, so slender that its nature could not be 

 examined. When rubbed upon paper it left an ashy feel, 

 and the copper under this crust was little brilliant, and co- 

 loured ; a circumstance which did not take place upon the 

 side of the negative pole. 



Two copper wires, less pure than the preceding, and of 

 the size of a writing-quill, were galvanized in two separate 

 tubes. A whitish cloud was soon seen to descend from the 

 positive wire, the matter of which even penetrated through 

 a double piece of parchment with which the inferior openintr 

 of the tube had been closed ; it arrived at the water of the 

 recipient common to both tubes, and was there converted 

 into hydrogenated oxide under the appearance of green flakes. 

 Upon the negative side a very small quantity of black hy- 

 drogenated copper was perceived; an effect which the au- 

 thor attributes to the impurity of the copper. The expe- 

 riment lasted twelve hours. The water of the two tubes, 

 and even that of the recipient, became alkaline. 



(d) Oxygenated Muriate of Tron, Hydrogenated Oxide of 

 Iron, and Alkaline Martial Tincture, p, oduced by Gal" 

 vanism. 



The author had observed, that by galvanizing in two sepa- 

 rate tubes, full of pure water, two iron wires, the one posi- 

 tively and the other negatively, there was formed in the po- 

 sitive tube, in less than sixteen hours action, an oxygenated 

 muriate of iron, I.e. with excess of oxide of iron j a cir- 

 cumstance which hindered the composition from reddening 

 I 4 the 



