1904.1 PHILLIPS — RADIUM IN AX AMERICAN ORE. 157 



perfect material, are thus confirmed in the most gratifying manner. 

 Many problems yet remain to be solved, however, especially the 

 osteology of the line leading directly into the modern horse. 

 Explorations will therefore be continued, especially the search for 

 the skeleton of Protohippus, with a view to ascertaining whether this 

 is or is not one of the direct ancestors of Equus caballus. 

 America7i Museiun of Natural History, 

 New York, April y, igo4. 



RADIUM IN AN AMERICAN ORE. 



BY ALEXANDER H. PHILLIPS. 



{Read Ajml S, 1904.) 



The work which I have accomplished in the separation of 

 radium, or more exactly the concentration of radium in barium 

 salts, has been carried on entirely with the mineral carnotite. 



Carnotite is comparatively a new mineral, having been described 

 by Friedel and Cumenge in July, 1899, and for this reason it is 

 noi: found in most books on mineralogy, and is therefore but little 

 known to the general prospector. It was first discovered in the 

 western part of Colorado, and occurs in Montrose, San Miguel and 

 Mesa counties of that State and the adjacent counties of Utah. 



The theoretical percentage composition as given by Friedel and 

 Cumenge is : 



UO3 63.54% 



V2O- 20. 1 2 " 



K2O IO-37 " 



HP 5.95" 



Results very close to these were obtained in the actual analyses. 

 The mineral formula is given as 2UO3, V.Oj, KoO, 3H0O, or a 

 uranyl potassium vanadate with three molecules of water of crystal- 

 lization. Hillebrand, after a series of analyses, disputes this com- 

 position, and holds that the mineral is probably a mixture to which 

 the above simple formula is not applicable. 



Carnotite is a light canary-colored powder disseminated through 

 a fine-grain sandstone. It is easily soluble in acids, and is treated 

 in this way for the commercial production of uranium salts. 



