Intelligence and Miscellaneous Articles. 389 



ing the peroxide as the pure protoxide— Ann, de Chim. et de Phys., 

 torn. li. p. 267. 



SEPARATION OF BISMUTH AND LEAD. 



M. Stromeyer observes that M. H. Rose in his work on analytical 

 chemistry, advises that the oxides of these metals should be treated 

 with sulphuric acid, which, when added in sufficient quantity, 

 completely dissolves the sulphate of bismuth. But this method, as 

 he has himself remarked, does not give very exact results, because 

 the sulphate of lead is not totally insoluble ; to this may be added 

 the fact, that if the operation is not quickly performed, sulphate of 

 bismuth is deposited in crystals, even from a very dilute solution. 



M. Stromeyer proposes the use of potash as a better method. 

 In many treatises on chemistry it is stated, that oxide of bismuth 

 is soluble in the alkalies, but this is an error. When the oxide is 

 boiled in potash, soda, barytes, or lime water, not the smallest 

 trace of it is dissolved. The alkaline carbonates dissolve carbonate 

 of bismuth j but this solution is decomposed by potash, which pre- 

 cipitates hydrated oxide. The small quantity of carbonate of potash 

 which the solution of caustic potash may contain, is incapable of 

 dissolving oxide of bismuth, as was determined by a direct experi- 

 ment. The carbonate of lead, on the contrary, being completely 

 soluble in the caustic alkalies, they offer a ready mode of separating 

 the two oxides. 



Both metals are to be dissolved in nitric acid ; potash or soda is 

 to be added in excess, and to be boiled for some time. The oxide 

 of bismuth precipitated in the state of hydrate, loses, like the hy- 

 drate of copper, its water during ebullition, and becomes yellow. 

 After washing, it is necessary only to dry it, for it would lose no 

 more weight by calcination. The oxide of lead may then be de- 

 termined by supersaturating the alkaline solution with acetic acid, 

 and precipitating, according to Rose, with oxalate of ammonia. It is 

 absolutely requisite that neither the nitric acid nor the potash should 

 contain any muriatic acid, for in that case a subchloride would be 

 precipitated, which the alkalies do not decompose, whilst they com- 

 pletely decompose the nitrate and the sulphate. — Ann. de Chim. et 

 de Phys., torn. li. p. 272. 



COMPOSITION OF OIL OF BITTER ALMONDS. 



MM. Wohler and Liebig have examined this oil, in which they 

 found in its crude state a considerable quantity of hydrocyanic 

 acid, as was proved by potash, a salt of iron and an acid. As the 

 experiments were instituted to account for the production of benzoic 

 acid from this oil, it was carefully mixed with hydrate of potash 

 and a solution of muriate of iron, strongly agitated, and then di- 

 stilled. All the oil came over with the water, but entirely freed 

 from hydrocyanic acid, and it was rectified over recently slacked 

 lime. The oil thus deprived of its hydrocyanic and benzoic acid 

 is perfectly colourless and limpid : it refracts light strongly. Its 

 smell is but little altered : its taste is burning and aromatic. Its 



