CERIUM. 381 



ness with an excess of acid till it became quite 

 colourless. Carbonate of ammonia was then 

 mixed with it in sufficient quantity to throw 

 down the protoxide of cerium in the state of a 

 carbonate. The carbonate of cerium, when al- 

 lowed to dry in the open air, was a very light, 

 bulky, white, tasteless substance, in small scales 

 or plates, somewhat resembling fhe appearance 

 of earthy talc. It was dissolved in dilute sul- 

 phuric acid till the acid refused to take up any 

 more. The solution was colourless, and on being 

 sufficiently concentrated deposited protosulphate 

 of cerium in small crystals, which had the form 

 of six-sided prisms, and some of them seemed to 

 be three-sided prisms ; but they were too small 

 to admit of any thing like an accurate measure- 

 ment of their angles. 



This salt has a flesh colour, a sweet taste, with 

 a slight degree of astringency, and the property 

 of reddening vegetable blues. It is pretty solu- 

 ble in water ; though the precise degree was not 

 determined. 



2. 15'6&5 grains of these crystals were dis 

 solved in distilled water, and the liquid mixed rium ana. 



Ivzed 



with a similar solution of 13 '25 grains of chlo- 

 ride of barium. A double decomposition took 

 place, sulphate of barytes precipitated, and the 

 residual liquid was not affected by sulphate of 

 soda nor muriate of barytes. Hence, it con- 

 tained no sensible quantity of sulphuric acid, or 



