78 Intelligence and Miscellaneous Articles. 



order to prevent any admixture of silica by using an agate mortar, 

 the mineral was powdered in a steel mortar. The powder was di- 

 gested in hot hydrochloric acid and carefully washed, in order to 

 dissolve the iron acquired from the mortar ; it was then dried and 

 weighed. It was then fused at a low red heat in a platina crucible 

 with six times its weight of freshly-prepared bisulphate of potash. 

 In half an hour the fusion and decomposition of the mineral were 

 complete ; the mass was dissolved in boiling water and filtered ; 

 there remained but a few unimportant particles of micaceous or 

 siliceous matter arising from an accidental admixture. The clear 

 solution was saturated with ammonia ; the alumina, glucina and 

 oxide of iron were thus precipitated and separated from the bisul- 

 phate of potash. 



In order to separate the alumina and oxide of iron from the glu- 

 cina, they were at first dissolved in a slight excess of hydrochloric 

 acid, and the solution was poured into a large quantity of solution of 

 carbonate of ammonia, which precipitated the alumina and oxide of 

 iron and retained the glucina ; but by this method only about 1 2 of 

 every 100 parts of glucina could be obtained. 



This process was therefore abandoned, and the method employed 

 by M. Awdejew was adopted ; this consists in dissolving the recently 

 precipitated alumina and glucina in a cold solution of potash, the 

 oxide of iron is thus separated ; the alkaline solution is then to be 

 diluted, and on boiling it, glucina is precipitated in white flocks, 

 which are easily washed ; it dissolves entirely in acids and in excess 

 of carbonate of ammonia ; the alumina retained in solution by the 

 potash is precipitated in the usual manner. 



The oxide of iron was observed in each operation to carry with it 

 a notable quantity of glucina ; in order to separate them they were 

 dissolved in hydrochloric acid ; the solution was supersaturated 

 with carbonate of ammonia, and the iron was precipitated with hy- 

 drosulphate of ammonia. The glucina was separated by boiling the 

 solution from which the sulphuret of iron had been precipitated ; 

 and after washing and heating to redness it was added to that px - e- 

 viously obtained. 



The mean of three analyses gave as the composition of cymo- 



phane, — • Alumina 75*26 



Glucina 18-46 



Peroxide of iron .... 4'03 



Sand 1-45 



99-20 



M. Damour remarks, that not knowing any mode by which to 

 determine directly the degree of oxidizement of iron in minerals not 

 acted upon by acids, he leaves undecided the question as to the mode 

 of its existence in the cymophane, as to whether it is in the state of 

 protoxide, or of peroxide isomorphous with alumina. — Ann. de Ch. et 

 de Phys., Fev. 1843. 



ACTION OF NITRIC ACID ON CARBONATE OF LIME. BY M. BAR- 



RESWIL. 



It is generally admitted by chemists as a fact, that marble is not 



