158 On Cerhint. 



Method of oltaimng Oxide of Ccrinm. 



(A.) Dissolve pure cerile, not calcined, in nitro-muriatic 

 acid, and, having saturated the clear solution with alkali^ 

 precipitate it by tartrite of potash. The precipitate, when 

 well washed, calcined, and digested in vinegar, contains 

 pure oxide of cerium. 



Or decompose a solution of cerium in nitro-muriatic 

 acid, still warm, but not saturated by succinate of ammo- 

 nia: a succinate of iron is gradually deposited. Continue 

 this precipitation by muriate of ammonia until a white pre- 

 cipitate appears. Leave the solution at rest, in order that 

 the small portion of succinate of cerium may be deposited. 

 The iron dissolved by the free muriatic acid deposits itself 

 at the same time, and the solution is obtained free from 

 that metal. You may then precipitate the cerium with 

 ammonia, and wash and calcine it. 



Of the Properties of Oxide of Cerium. 



(B.) This oxide may appear under dift'erent degrees of 

 oxidation. Alkalies precipitate from its solutions a whit« 

 oxide, which in the air has a yellowish colour, but which 

 when perfectly dry becomes dark. When exposed to a 

 strong heat, long continued, it assumes a dark brick colour. 

 The oxalate and acetate of cerium, when calcined in vessels 

 not completely shut, give a white oxide, which on an open 

 fire becomes of a brick colour. It does not fuse alone. 



Treated bv the blowpipe with borax, it readily fuses and 

 swells up. The globule struck, by the external flame, as*- 

 sumcs a blood colour, which by cooling passes to a green- 

 ish yellow, and at length becomes colourless and acquirer 

 complete transparency. Fused by the interior flame, these 

 changes do not take place : It is then reduced to colourless 

 glass, but when exposed a little time to the exterior flame 

 the same phoenomcna arc exhibited. If too much oxide of 

 cerium be employed, the glass resembles yellowish opake 

 enamel. These changes are manifested more readily with 

 phosphates of soda and of ammonia. If two clear colourless 

 globules, one of which is made with borax and the other 

 with phosphate, be fused together, they give a transparent 

 glass, which on cooling becomes of an opake pearl colour. 



These characters taken together distinguish oxide of ce- 

 rium from oxide of iron. The latter presents the same 

 changes of colours ; but its glass, after it has been cooled, 

 has a dark green fugitive colour. 



The globules of borax and phosphate fused together give 

 an opake glass, the colour of which is a little darker. 

 [To be continued.] 



XXVII. Me^ 



