Intelligence and Miscellaneous Articles. 229 



with sulphuric acid and peroxide of manganese ; but in order to 

 prevent the formation of sulphuric aether, it is proper to employ 

 weak alcohol or common brandy ; for if the alcohol is concentrated, 

 there is formed not only sulphuric aether, but also formic aether, 

 which not only diminishes the quantity of formic acid, but occasions 

 it to give a difficultly crystallizeable and coloured salt, with lead. 

 Acetic acid treated in the same manner does not yield formic acid ; 

 the fibrin of blood yielded some, but it was very impure. — Ann. de 

 Chimie, Feb. 1850. 



BI-IODATE AND TRI-IODATE OF POTASH. 



M. Serullas finds that there are two acid iodates of potash, — a bi- 

 iodate of potash formed of 2 atoms acid and 1 atom base, and a tri- 

 iodate, consisting of 3 atoms acid and 1 atom base. The first is 

 produced by the incomplete saturation of chloride of iodine by pot- 

 ash, in the form of a double crystalline compound, which being 

 separated, dissolved, and crystallized, gives the bi-iodate. 



The other results from the action of one of the following acids : 

 sulphuric, nitric, phosphoric, muriatic and silicated fluoric upon the 

 neutral iodate of potash ; sulphuric acid is to be preferred ; or it may 

 be prepared by supersaturating potash with iodic acid. 



During the incomplete saturation of chloride of iodine by potash, 

 and consequently under the influence of excess of muriatic acid, 

 there is formed a double compound, well crystallized and in definite 

 proportions, of chloride of potassium and acid iodate of potash. No 

 acid iodate or chloriodate of soda appears to exist ; in order to ob- 

 tain iodic acid, soda may be precipitated from the iodate by means 

 of silicated fluoric acid, the excess of which is volatilized during the 

 operation. This process M. Serullas prefers to Davy's by means of 

 oxide of chlorine and iodine. — Ibid. 



POWER OF METALLIC RODS OR WIRES TO DECOMPOSE WATER 

 AFTER THEIR CONNECTION WITH THE GALVANIC PILE IS 

 BROKEN, 



In the experiments which I undertook in 1806-7, in company with 

 Mr. Hisinger, we had found that rods of metal which were employed 

 to decompose water by means of the galvanic pile continued to deve- 

 lope gas after their connection with the pile had ceased, — a circum- 

 stance which seemed to indicate a continuance of electrical state, 

 though these rods showed no action upon any other portion of liquid, 

 even of the same kind, than that in which they had been placed du- 

 ring their contact with the pile. This observation, which I had al- 

 most forgotten, has been lately confirmed by Pfaff, who has also 

 added to it several others of a similar kind. We might suppose such 

 effects to be produced by a residual polarity, both in the liquid and 

 the metal, showing itself, as long as it continued, by a continuance 

 of chemical action ; but some of Pfaff's experiments seem to oppose 

 this idea, for he found that the addition of ammonia to the liquid, by 

 which all its internal polarity was destroyed, did not deprive the 



wires 



