500 T. L. WATSON WEATHERING OF ALLANITE 



but of essentially the same constituents in widely varying ratios, which 

 finds expression iji inequality of leaching. The weathered product is 

 composed essentially of water, ferric oxide, alumina, ceria, and silica, the 

 other constituents of the fresh mineral having been removed, with but 

 few exceptions almost, if not entirely, in solution. It does not represent 

 a liomogeneous substance of definite chemical composition and can not 

 be expressed by any fixed chemical formula. 



