392 Miscellaneous Intelligence. 



Iron 



Silica 



Nickel 



Magnesia .... 

 Sulpliur ..... 



99.0 

 Mem. du Museum, ii. 89. 



12. On the Presence of Titanium in Mica. — M. Vauquelin has re- 

 peated the experiments of M. Peschier, of Geneva, on the existence 

 of titanium in mica; and has found that metal in all the varieties of 

 mica examined, though, where most abundant, it never amounted to 

 one per cent. M. Vauquehn's process was as follows : the mica 

 divided into very thin plates, and cut by scissors, was heated for half 

 an hour with two parts of caustic potash; the mixture was diffused 

 through 100 parts of water, (generally yielding a green solution 

 from the presence of manganese,) and muriatic acid was added 

 until in slight excess, which caused solution of the whole, if the 

 fusion with potash had been Avell performed. The solution was 

 slowly evaporated, especially towards the last, and a powder 

 obtained, either white or coloured, according as iron was absent 

 or present. This powder, thrown on a filter, was washed first with 

 cold and then with hot water. If the siHca remaining was coloured, 

 it was acted upon by cold muriatic acid, diluted with ten of 

 water, until white; thus freed from iron, it was afterwards boiled 

 in strong muriatic acid, and the solution diluted, filtered, and 

 evaporated ; when almost all the acid was driven off, the liquid was 

 again diluted, and tested by infusion of galls. If titanium were 

 present, a reddish yellow precipitate took place after some hours, 

 of tannate of titanum. M. Vauquelin also examined the washings, 

 but the operation, &c., if well performed, always gave titanum with 

 the silica, if any were contained in the mineral. — A)in. de. Chim. 

 xxvii. 67. 



13, Decomposition of Metallic Sulphates hy Hydrogen, by 

 M. Arfwedson. — The apparatus used in these experiments 

 •was a tube of difficultly fusible glass, in the middle of which was 

 blown a bulb to contain the sulphate operated upon. The 

 hydrogen or sulphuretted hydrogen used was dried by chloride of 

 calcium. . 



Dried Sulphate of Manganese was not affected by the hydrogen, 

 until at a dull red heat ; it then gave water and sulphurous acid, and 

 became brown: when cold, a green powder was obtained, dissolving 

 without effervescence in muriatic acid, and evolving sulphuretted 



