188 Miscellanies, 



less with metallic copper, while oxygen continued to flow from the 

 positive wire. He varied the experiment by trying other metallic so- 

 lutions: silver and lead, and some others, presented the same phenom- 

 ena, except that the silver and lead were transported in the metallic 

 state, while in other cases only the oxide was deposited. 



We must, in these cases, suppose, either that the hydrogen com- 

 bines with the m.etal, or that the metal, separated in the state of ox- 

 ide, is reduced by the hydrogen, which forms water by its combina- 

 tion with the oxygen of the oxide. The latter supposition only is ad- 

 missible. To assure himself of irs truth, he took a pile of two pairs, 

 incapable of decomposing M^ater slightly saline. A solution of nitrate 

 of silver, of much easier decomposition than water, was easily decom- 

 posed, and it was observed that there was at first deposited, not me- 

 tallic silver, as Avas common, but an olive coat of oxide of silver. 

 Thus it is proved that the disengagement of hydrogen at the negative 

 pole ceases, only because this gas is employed in reducing the oxides 

 separated from their combination with acids, by the electric agent. 



Thus it appears that hydrogen, in its nascent state, is capable of 

 decomposing oxides, a property it does not commonly possess, ex- 

 cept at elevated temperatures. 



In pursuing the investigation, the author took a pile of two pairs, 

 charged with water Very slightly saline, and which could not, of 

 course, decompose even acidulated water. He placed the platina 

 wires of this pile in a solution of chloride of copper, and observed, 

 in the course of time, that the negative wire was acquiring a coating 

 of metallic copper, while from the positive wire bubbles of gas were 

 rising. Having changed the platina conductor for one of silver, the 

 latter acquired a yellow coating, which soon became violet, and 

 which led him to suspect the presence of chloride of silver. The ex- 

 periment was repeated with iodide of zinc and of iron ; and scarcely 

 were the platina wires plunged into these solutions, Avhen the iodine 

 appeared, distinctly, at the positive pole, and the metal was reduced 

 at the negative pole. 



From these experiments the author thinks it may with certainty be 

 affirmed, that these combinations, even when dissolved in water, do 

 not change their nature, and are not converted, as chemists have of- 

 ten imagined, into hydro-chlorates, hydriodates, &c., of oxides. — 

 Forli, 10 Sep. 1S30.— Bib. Univ. Oct. 1830. 



10. The Black Sea. — Dr. P. C. Hepites, of Odessa, has analyzed 

 the water of this sea, with the following results: Spec. grav. 1011. 

 10,000 parts of the water being evaporated at a low heat, left 65 parts 

 ef a yellowish residue, which consisted of 



