ELISHA MITCHELL SCIENTIFIC SOCIETY. 



39 



dite and kararfveite. These were all shown, by the 

 patient investig-ations of renowned mineralogists, to be 

 identical with monazite, and that name was retained 

 because at the time it was criven it represented a crys- 

 talloo-raphically as well as chemically known mineral, 

 while the attributes of the others were not so well es- 

 tablished until later. And so the name monazite is in 

 common use to-da}^ 



CHEMICAL COMPOSITION. 



Chemically, monazite is an anhydrous phosphate of 

 cerium, lanthanum and didymium. It also contains, 

 almost invariably, small percentages of thoria and sil- 

 ica; and some of the more complete analyses have 

 shown the presence of vttria, erbia. alumina, ferrous and 

 ferric oxide, lime, magnesia, manganese, tin and lead 

 oxides, fluorine, zirconia, tantalicaud titanic acids. Un- 

 doubtedly most of these latter existed as impurities, in 

 all probability, attached to the monazite. Below are 

 given a few detailed analyses from various localities. 



ANALYSES OF MONAZITE. 



