166 



orange red while hot and colorless when cold. With salt of phos- 

 phorus it fuses into an opaline glass, which is orange red while hot 

 but colorless when cold. 



In this glass white particles of silica remain undissolved, and 

 communicate to it a milky opalescence. 



When a fragment of the mineral is fused with salt of phospho- 

 rus, there remains in the bead a skeleton of silica. 



With gypsum the mineral fuses readily and forms a greenish 

 yellow enamel, which becomes lighter colored in R. fl. 



When the pulverized mineral is made into a paste with sulphu- 

 ric acid in a plaiina crucible, and a waxed plate of glass, with let- 

 ters marked through the wax is placed upon it ; on application of 

 heat to the crucible the letters become rapidly and deeply etched 

 in the glass, demonstrating the presence of fluorine. 



The above characters shew that this mineral differs somewhat 

 from the Yttrocerite of Sweden, but these differences arise from 

 the presence of some additional foreign matters as will be seen by 

 the following analysis : 



One gramme of the mineral was crushed to powder in a steel 

 mortar, and then rubbed to impalpable powder in one of agate. 



It was then dissolved in chlorhydric acid and formed a lemon 

 yellow solution, leaving a portion of silicate of cerium undissolved. 



The solution was then analyzed according to the directions of 

 Berzelius, by means of a crust of crystals of sulphate of potash, 

 which threw down a white powder of sulphates of potash cerium 

 and yttria. The yttria salt was then dissolved out by a concentra- 

 ted solution of sulphate of potash, and the cerium salt collected 

 was dissolved in boiling water, and the oxide of cerium precipita- 

 ted by means of a solution of pure potash. The lime was separa- 

 ted as a sulphate and the alumina was precipitated by carbonate of 

 ammonia. The fluorine was determined by the difference in 

 weight of the mineral, and the results obtained. 



Oxide of lanthanium is inferred to be present from the color of 

 the cerium obtained, no accurate process for its proportional sepa- 

 ration yet being made known. 



The results of the analysis on 1 gramme were as follows : 



Lime, — .347 



Yttria, = .155 



Oxides of Cerium and Lanthanium, . = .133 



