Intell'mence and Miscellaneous Articles, 235 



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nitric or muriatic solution of these oxides sufficient to saturate them ; 

 ammonia is to be poured into the solution, which occasions a pre- 

 cipitate, which is redissolved by excess of ammonia. The liquor 

 assumes a greyish blue or violet tint, according to the proportions of 

 the two oxides. Exposed to the air in an open vessel, this solution 

 loses the excess of ammonia, and becomes turbid. The deposit 

 formed consists of a double paraphosphate of nickel and ammonia, 

 at first of a greyish colour, and then of a fine green. When the li- 

 quor becomes clear, the solution is of a fine rose colour. If it con- 

 tains no nickel, it may be evaporated without becoming turbid, to 

 the consistence of a syrup. The two salts being thus isolated, the 

 paraphosphoric acid is to be separated either by the hydrosulphuret 

 of ammonia or by carbonate of soda. 



SEPARATION OF OXIDE OF CADMIUM AND OXIDE OF BISMUTH. 



Paraphosphate of bismuth is insoluble in solution of ammonia, 

 while paraphosphate of cadmium dissolves readily in it as long as 

 there is excess of ammonia. If, then, these two oxides are dissolved 

 by nitric acid and paraphosphoric acid be poured into the solution, 

 all the bismuth is precipitated. After having washed the precipitate 

 with solution of ammonia, all the cadmium will be removed j and 

 it only remains to separate the oxides from the paraphosphoric 

 acid. 



This method may also be applied to the separation of the oxides 

 of lead and mercury, the latter forming a soluble salt with the para- 

 phosphoric acid and ammonia, whilst the oxide of lead forms an in- 

 soluble one. 



The paraphosphoric acid employed by M. Person is obtained by 

 calcining pure phosphate of ammonia. 



Separation of oxide of uranium from the oxides of cobalt, nickel^ and 

 zinc. — Oxide of uranium may be completely separated from these 

 three oxides, by using subacetate of lead; for a solution of this salt 

 poured into a solution of nitrate of uranium, cobalt, nickel, and 

 zinc, forms a precipitate of uranate of lead, which is completely in- 

 soluble in excess of a solution of subacetate of lead j whereas, under 

 the same circumstances, the insoluble compounds of oxide of cobalt, 

 of nickel, and of zinc with lead, dissolve very readily in excess of 

 the subacetate. It was in this way that Mr. Person discovered 

 cobalt in combination with uranium, under circumstances in which 

 other methods would be unavailable. — Ann, de Chim. et de Phys,y 

 t. Ivi. p. 333. 



ACTION OF MURIATE OF AMMONIA ON CERTAIN SULPHATES. 



M. Vogel finds when equal bulks of strong solutions of muriate of 

 ammonia and protosulphate of iron are mixed, small transparent 

 crystals of a bright yellow colour are formed in twenty-four hours. 

 These crystals are very hard, and much less soluble in water than 

 sulphate of iron. 



When these crystals are heated by a spirit-lamp in a glass, they 

 swell a little without fusing ; they become of a dull white and opake ; 

 water evaporates, and afterwards ammonia and sulphate of ammonia. 



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