506 Analysis of Cerium Ochre. 



This mineral has the following characters: — 



Before the blowpipe alone, on charcoal, it turns brown, 

 but does not melt. With soda, it forms an opaque, greenish- 

 yellow bead, which becomes almost white by cooling. With 

 borax, it dissolves readily into a transparent glass, which is 

 orange red while hot, and nearly colorless or pale green when 

 cold. It retains this pale green color in Rfl. 



With salt of phosphorus, dissolves into a glass, which is 

 orange red while hot, and pale green when cold. In Rfl. it 

 still retains this green color. 



When the salt of phosphorus is saturated with this min- 

 eral, it becomes opaque when cold, and has a greenish tinge. 



The mineral dissolves in warm hydrochloric acid, and 

 forms a lemon-yellow solution, from which crystallized sul- 

 phate of potash throws down a white powder, which is sul- 

 phate of cerium, yttria, and potash. The yttria being sep- 

 arated, and the cerium precipitated from its solution in hot 

 water by potash, and then heated to redness, becomes brown, 

 and has the usual characters of a mixture of the oxides of 

 cerium and lanthanium. 



When the usual test is applied for the detection of fluorine, 

 a slight etching of the glass is discovered. 



From the above researches, it appears that we have several 

 interesting combinations of cerium among the minerals of 

 Bolton. I long ago suspected that the pink color of the 

 petalite was due to the presence of cerium, having observed 

 that color surrounding the Allanite whicli occurs in it. The 

 circumstance that the pink scapolite does not become brown 

 or black by exposure to the action of the atmosphere, caused 

 me to suspect that its pink color was not due to the presence 

 of oxides of iron or manganese ; and the above remarks have 

 proved that the cerium ore is its coloring matter. 



In effecting the above analyses, I have been assisted by my 

 pupil, Mr. Joseph S. Kendall, who has repeated every process 

 in the analysis. 



