Intelligence and Miscellaneous Articles. 61 



chromiite, a deep yellow coloured precipitate is formed. A yellow 

 liquid remains, which being decomposed by solution of potash, also 

 gives an abundant precipitate, but of a paler colour : these colours 

 may be employed either in oil or with varnish. — Ibid. 



GREEN LAKE PREPARED FROM RED CABBAGE. 



M. Lampadius states, when a hot infusion of red cabbage is treated 

 with a solution of acetate, or still better, subacetate of lead, a very 

 fine deep grass green lake is obtained. Muriate of antimony with a 

 similar infusion gives a rose red precipitate. Infusion of cabbage 

 may be employed to dye cotton and linen of these colours, after hav- 

 ing used acetate of lead and muriate of antimony as a mordant. — 

 Ibkl. 



DECOMPOSITION OF SULPHURET OF CARBON BY ELECTRICITY. 



M. Becquerel puts some sulphuret of carbon into a tube, under a 

 solution of nitrate of copper of less specific gravity ; a plate of copper 

 is then placed in both li(juids : these substances form a pile. 



The carburet of sulphur is decomposed, as well as a portion of 

 the nitrate of copper ; many crystals of protoxide of copper are 

 formed on the copper plate, and carbon in very small brilliant laminae, 

 and of a metallic appearance, is deposited on the sides of the tube — 

 Annales de Chimie, Sept. 1829. 



DETECTION OF ADULTERATION IN CHROMATE OF POTASH. 



M. Zuber states that this salt is frequently adulterated with muriate 

 or sulphate of potash ; and he proposes the following method of de- 

 tecting them : Add a large excess of tartaric acid to the chromate of 

 potash to be tried, the chromate will be decomposed, and acquire in 

 about ten minutes a deep amethyst colour. It will now, if pure, form 

 no precipitate with nitrate of baryles or silver, by which means the 

 presence of muriate or sulphate of potash may be ascertained. — Ibid. 



REMARKS ON ONE OF THE EXPERIMENTS FROM WHICH MR. 

 RITCHIE HAS INFERRED THE INADEQUACY OF THE CHEMI- 

 CAL THEORY OF GALVANISM. 



In Mr. W. Ritchie's " Experimental Examination of the electric 

 and chemical Theories of Galvanism," lately published in the second 

 part of the Philosopiucal Transactions for the present year, it is stated 

 towards the conclusion of the paper, (Phil. Trans. 1829, p. 3(j.5,) that 

 " the following experiment is not ordy at variance with the theory of 

 Dr. Wollaston, [which " assumes that positive electricity is set at li- 

 berty by the combination of oxygen with one of the metals" in a gal- 

 vanic arrangement,] but seems also hostile to some of the generally 

 received notions of chemists " 



For this cx])i'rimeiit a cylinder of copper is employed, (of which a 

 figure is given in the Transactions,) about an inch in diameter, and 

 two inches long, having a small copper tube soldered in one vtu\, 



whilst 



