the Origin of Radium. 



609 



Xo. 



1. 

 •_» 



5'. 



4. 



5. 



6. 



7. 



8- 



i>. 

 10. 

 11. 

 12. 

 13. 

 14. 

 15. 

 16. 

 17. 

 Is. 



19. 

 20. 

 21. 

 00 



Substs 



Uraninite 



Uraninite 



Gummite 



Uraninite 



150-7 

 147-1 

 120-7 

 131-8 



Uranophane 



Uraninite 



Uranophane 



Xhoroguniinite 



Carnotite 



108-0 



1125 



88-8 



611 



41 6 



Uranothorite 



24*9 



Samarskite 



Oransite 



23 2 



22*84 



luixemte 



198 



Thorite 



Fergusonite 



iEschynite 



15-6 

 11-95 

 9-9S 



Xenotime 



Monazite 



114 



0-88 



Monazite 



0-84 



Monazite 



076 



Monazite 



Allanite 



0-63 



0014 



II. 



193 



8-0 

 20-3 

 7 "8 

 9-7 

 3-1 

 247 

 US 

 81 

 0-3 

 0-16 

 0-26 

 010 

 1-0 

 07 

 002 

 0-40 

 000 

 0-01 



o-oo 

 o-oo 



. 000 



111. IV. 



L70-0 



1551 

 1470 

 139*6 



117-7 

 1 15-0 

 1 135 

 72-9 

 49-7 

 25-2 

 23-4 

 23-1 

 19-9 

 16-0 

 12-0 

 100 

 1*54 

 0-88 

 0-85 

 0-76 

 63 



11-3 



5-2 



13-7 



5 



8-2 



27 



22-8 



10-2 



16-3 



1-3 



0-7 



1-1 



05 



6-2 



5 



0-2 



260 



1*2 



V. 



v, 



0-7465 



228 



0-6961 



223 



0-053* 



225 



0-6174 



220 



0-5 L68 



228 



0-5004 



228 



0-4984 



228 



03317 



220 



0-2261 



220 



01138 



221 



01044 



224 



01034 



223 



00871 



228 



0-0754 



220 



0557 



215 



0-0452 



221 



0070 



220 , 



0-0043 



205 



00041 



207 | 



00034 



223 



0-0030 



210 



(0-00007) 





conclusion is that uranium is the parent o£ radium*. The 

 participation b}^ thorium in the production of radium, which 

 has been suggested by some, is entirely excluded, since the 

 radium-uranium ratio in the thorites, containing approxi- 

 mately 50 per cent, of thorium, is the same as that in such 

 mineral- a- carnotite and uranophane, where the content o£ 

 thorium is not over a few hundredths of a per cent, at the 

 highest. 



The results obtained with monazite are of interest, in view 

 of the recent controversy over the composition of this mineral 

 substance. It was originally stated by Hof matin & Zerban f 

 that Brazilian monazite, from which they, at that time, claimed 

 to have separated inactive thorium, contained no uranium. 

 In a later publication, the -nine authors J credit monazite 

 with containing about O'l per cent, of U 3 8 , on the authority 



• Rutherford, in his book on ' Radioactivity ' (p. 334), after pointing 

 out the various reasons for assuming- that radium is a disintegration 

 product of some other element, and showing- that the requirements of a 

 parent element are more nearly fulfilled by uranium than by any other 

 element, adds the following :—" Taking into account the presence of 

 polonium and actinium in pitchblende, the activity of the Lest pitchblende 

 is about tin- name as would be expected if radium were a disintegration 

 product of uranium. If this hypothesis is correct, the amount of radium 

 in any pitchblende should be proportional to the amount of uranium 

 present, provided the radium is not removed by percolating water.'' 



t Bertchie <L 1). Chem. GeseU. xxxv. p. 532 (1002). 



t I hi'/, xxx vi. p. 3098 (1903). 



