of Mineral Substa?ices. 265 



solutions are colourless, but become reddish-purple if concen- 

 trated. 



k. Sulphate of cerium crystallizes in truncated octoedra of a 

 pale amethyst colour, and very difficultly soluble. 



i. Nitrate of cerium is difficultly crystallizable and deli- 

 quescent. 



k. Muriate of cerium forms prismatic crystals. Chlorine is 

 evolved during the digestion of oxide of cerium in muriatic 

 acid. 



/. Acetic acid scarcely acts upon oxide of cerium, but it easily 

 dissolves the carbonate, forming a very soluble white salt. 



7)1. Sulphate of soda added to nitrate or muriate of cerium, 

 forms a difficultly soluble white precipitate of subsulphate of 

 cerium. This precipitate boiled in a solution of carbonate of 

 soda, yields a perfectly pure carbonated oxide of cerium. 



n. Sulphurous acid dissolves oxide of cerium, and the solu- 

 tion affords prismatic crystals of a pale amethyst colour. 



0. The neutral phosphates, tartrates, and succinates form white 

 precipitates in jiitrate and muriate of cerium, which are soluble 

 in acids. 



p. Oxalic acid and the neutral oxalates occasion a precipi- 

 tate in the solutions of cerium, which, unlike the former, is in- 

 soluble in nitric and muriatic acid. 



9. Prussiate of potassa produces a white precipitate soluble 

 ill the acids. 



r. Tincture of galls occasions no change. 



s. Neither does sulphuretted hydrogen produce any change 

 in the oxide of cerium; the precipitate occasioned in its soilii- 

 tions by hydro-sulphuret of ammonia, is of the same whitish- 

 yellow colour as when pure ammonia is used. 



Analysis of a compact Ore of Titanium from Arendal. 



a. 300 grains of this ore in fine powder were fused with six 

 times their weight of carbonate of potassa ; when cold a groy 

 porcellaneous mass was obtaned, which by digestion in water 

 alforded a carbonate of titanium, weighing, after having been 

 washed and dried, 620 grains. 



Vol. XII. T 



