srrcKssiox >i-- (|I\N<;KS IN i;\ \<TIYI BOD1B& 211) 



There is one direct method of attack of the question. If uranium \H the parent of 

 rudium, the amount of radium for different pitchblendes should always l>e proportional 

 to the amount of uranium present.* The origin of the other radio-elements could \te 

 attacked in a similar way. 



The whole subject of the relative connection and origin of the radio-elements is of 

 the greatest interest and importance. The close similarity of the changes in radium, 

 thorium and actinium is very remarkable and indicates some peculiarity of atomic 

 constitution which still remains to be elucidated. 



* BOI.TWOOD has recently published some numbers ('Nature,' May '25, 1904, p. 80) which seem to show 

 ilia i in the pitchblendes examined the amount of radium is strictly proportional to the amount of uranium 

 in the mineral. Further results of this character are very much required. 



2 F 2 



