vnaie on a ]\ri/ieral called Cerile. 1 Qg 



colour and a foliaceous texture. There was also in the neck 

 of the retort a slight reddish covering, the taste of which 

 was exceedingly acrid and metallic : the quantity of the 

 matter which formed this covering was too small to be sub- 

 jected to experiments capable of determining its nature. 



Three of these small metallic globules, which weighed 

 together scarcely a fourth part of a grain, being put suc- 

 . cessively into nitric and muriatic acid, were not sensibly 

 attacked : to effect the solution of them the union of these 

 two acids was necessary. The solution being evaporated, 

 and its residuum dissolved in water, had no colour ; its taste 

 was sensibly saccharine ; aad by the oxalate of ammonia 

 and the prussiate of potash it gave white and flaky precipi- 

 tates. It appears, then, that these globules, which I sus- 

 pected to be iron, are really cerium. What is certain is, 

 that these globules are much'more fragile, whiter, and less 

 liable to be attacked by acids than cast iron. 



These experiments prove that cerium is volatile at a high 

 temperature, and that it is probably only at the moment of 

 its volatilization that it is reduced, unless we suppose that 

 it is rather volatilized in the state of oxide. This I propose 

 to ascertain by new trials. 



Recapitulating what has been said in the course of this 

 notice, it is seen, 1st, That cerium, freed from the foreign 

 matters which accompany it in the mineral, is a substance 

 susceptible of uniting with two quantities of oxygen very 

 distinct, 



2d, That with the first quantity it forms a white sub- 

 stance, soLuble in acids, without any disengagement of ox- 

 ygen. 



3d, That with the second portion it assumes a slight red 

 colour, combines only with difficulty with acids, and con- 

 stantly produces a considerable quantity of oxygenated mu- 

 riatic acid by dissolving in common muriatic acid. 



4th, That these oxides do not dissolve in alkalies ; but 

 that when boiled together they no longer become coloured 

 by the contact of the air ; and that those which are red be- 

 come white by a slight heat, without, however, combiaing 

 with the alkalis. 



5th, That their combinations with the sulphuric, phos- 

 phoric, oxalic, tartareous, and prussic acids are white, and 

 insoluble in water. 



Gth, That, on the other hand, those which thev form with 



nitric, muriatic, and acetic acids are very soluble in water 



and la alcohol, and are even deliquescent. 



N4 



7th, Tli 



