Ratio between Uranium and Radium in Minerals. 653 



means of sodium carbonate, estimated as pyrophosphate as 

 before. 



Table I. contains the results of the estimation o£ uranium 

 in the various minerals. The thorianites were all specimens 

 of Ceylon thorianite. " Th I, Th I a, Th 1 b " were from 

 the same sample of the variety richest in uranium and con- 

 taining a small residue (3 per cent.) insoluble in acid. 

 " Th X 2 " was a poor specimen of the mineral, and contained 

 nearly 24 per cent, of insoluble material. "ThCCC'and 

 " Th E " were specimens of mixtures of the two varieties 

 (which differ chiefly in their respective high or low percentage 

 of uranium). The pitchblende "PI" was a specimen from 

 Joachimsthal which contained comparatively little uranium 

 and proved troublesome in the analysis and unsatisfactory in 

 the results. The other (" J.P. A " and " J.P.B ") was a picked 



Table I. 





P 



S £ 



11 



fThl, Thla, Thlb.. 



I 



I ThX 2 l&2 



| ThCCC 



LThE 



( PI 



Ij.P.A, J.P.B 



G.E.A.P r 



German East African \ 



pitchblende. 

 f A I, All 



Isr 



Pilbarite 



Percentage of Uranium. 



(1) 

 20-80 a 



(2) 

 20-11 c 



(3) 



(4) 



, (5) 



Mean. 



19-86 c 



19-32 c 



19-80 c 



1 20-06 



20-56 b 



20-28 d 



J9-99rf 



19-74 d 



20-15 rf 



9 49 a 

 939 6 



10-71 d 



10-40 d 



1 





10-00 



13-02 a 



14 04 a 



13-44 a 



} 





13-61 



13-20 b 



14-14 6 



13-82 6 





17-21 a 

 17-93 b 



17-42 a 

 17-95 b 



1 









1762 



33-35 c 



28-06 o 



30-81 d 



34-99 a 



31-20 e 



1 31-86 



33-57 d 



28-22 d 





34-71 6 





62-37 a 



60-73 a 



6177 c 



61-34 a 



} 



61-23 



61-39 6 



59-98 b 





61-01 6 



72-30 c 

 70-31 d 



} 









7P3 



20-04 a 



19-90 a 



1954 d 



2V56 d 



1995 a 

 19-65 6 



] 20-10 



47-82 a 



47-85 a 



I 







48-44 



49-30 b 



48-79 6 







20-45 a 



21*16 a 



} 







21-28 



20-85 b 



21-72 6 







* The other autunites referred to in Gables II. and III. -were used in 

 connexion with other work (Le Radium, 1910, vii. p. 295), and details of the 

 uranium analysis need not be given. 



a denotes that the uranium was weighed as the green compound before con- 

 version into pyrophosphate. 

 6 ,, „ ,. ,, as uranium pyrophosphate. 



o „ „ „ „ asU 3 0,. 



d „ „ „ „ a? U0 2 . 



* >> >• „ „ as sodium uranate. 



