244 Boltwood — Production of Radium from Uranium. 



protected from contamination by the salts of radium or other 

 radio-active substances, and that the electroscope used has been 

 reserved for this particular research, its original normal air- 

 leak having remained unaltered throughout the entire period. 

 It has therefore been unnecessary to introduce any corrections 

 or to make any allowances for possible errors due to known 

 causes of any description. 



The experiments described in this paper are considered to 

 indicate that the results obtained by Mr. Soddy are without 

 significance and that one or more products of a slow rate of 

 change intervene between uranium and radium. 



It is claimed, moreover, that the conclusions in Mr. Soddy's 

 first paper, so far as they relate to the direct transformation of 

 uranium into radium, are more truly in accord with the actual 

 facts than are those contained in his later publications. 



139 Orange street, New Haven, Conn. 

 August, 1905. 



