78 Intelligence and Miscellaneous Articles. 



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inches, a pair of common bellows, with a glass tube attached to the pipe, 

 which pipe was introduced into a green glass bottle containing 12 

 ounces of distilled water, acidulated with 2 drachms of nitric acid. The 

 apparatus being thus arranged, the bellows were set in action, by which 

 means the atmosphere, loaded with the moisture from the lead, was 

 made to pass in a continued current through the liquid : this was con- 

 tinued for six hours. The whole was then transferred into a platina 

 dish and evaporated to perfect dryness. The residue was dissolved 

 in one ounce of distilled water with two drops of nitric acid to insure 

 the solution of the lead should any be present. A current of sulphu- 

 retted hydrogen was next passed through the solution, which immedi- 

 ately gave a minute dark precipitate ; this being collected on a filter 

 and washed, was transferred to a watch-glass, and treated in the usual 

 manner with nitric acid to decompose the sulphuret, which gave on 

 the application of hydriodate of potash the most unequivocal proof of 

 the presence of lead. 



Another experiment was conducted at the same time with similar 

 vessels in the same room, but the current of air was not passed through 

 the liquid. This on the application of sulphuretted hydrogen gave not 

 the least indication of lead, but, on evaporating the whole to dryness 

 and treating the residue in the manner before described with hydrio- 

 date of potash, the slightest possible trace of the yellow iodide of lead 

 was perceptible. The nitric acid and distilled water were separately 

 tested with great care, but were found perfectly free from lead, so that 

 no doubt the trace of lead must have been absorbed from the atmo- 

 sphere,as the bottle containing it stood beside the one through which 

 the current of air was passed. I ought to have mentioned before that 

 the temperature of the laboratory during the experiment was from 

 70° to 80° Fahr.,and that the door was kept closely shut that the air 

 might be loaded as much as possible with the vapour. 



DECOMPOSITION OF CYANURET OF MERCURY BY IRON. 



A question having arisen as to the propriety of heating prussian 

 blue and peroxide of mercury in an iron vessel for preparing cyanuret 

 of mercury, on account of the supposed decomposition of the salt by 

 the iron, M. Guibourt, in order to decide the question, dissolved some 

 cyanuret of mercury in distilled water, and placed a plate of iron in 

 the solution. In a few hours spots of oxide appeared on the iron, 

 and the solution when agitated had an ochreous tint. The next day 

 the oxidation of the iron had made great progress, and the liquor had 

 acquired a sensible odour of hydrocyanic acid. The action continued 

 during four days : the iron was then almost entirely oxidized on the 

 surface, corroded in several spots, which had a bluish black colour, 

 indicating the formation of prussian blue. The liquor had a strong 

 smell of hydrocyanic acid, and contained much iron in suspension ; 

 and at the lower part of the plate of iron, and the bottom of the 

 bottle, globules of mercury were observed in considerable quantity. 



The liquor was shaken and thrown upon a filter : the globules re- 

 mained at the bottom of the bottle j the oxide of iron was retained by 

 the filter, and the colourless liquor passed through it. It did not act 



