THE INFLUENCE OF RADIUM ON THE 



Table I. 





No. of cc. of ^25?) NaoS,_,Oa 



solution required 





in titration when hydriodic acid solutions 



Time in liours. 



were madt; up with 







Water of conductivity Water of conductivity 





4.98 X 10-«. 



2 16 X 10-6. 



7 



0.73 





0.90 



11 



0.97 





i.:4 



15 



1.38 





1.40 



20 



1.68 





1.63 



25 



2.05 







30 



2.45 





1.70 



35 



2.S0 







40 



2.86 





1.95 



50 



3.20 





.... 



70 



4.05 







95 



4.37 





3.08 



120 



4.25 





3.35 



170 



3.75 





3.24 



200 



3.24 





3.24 



800 



3.45 





3.22 



380 



1.58 





3.23 



450 







3.21 



550 



.... 





3.25 



650 



0.89 





3.20 



1100 



.... 





3.24 



From an examination of this table it will be seen that there 

 is a striking difference between the behaviour of solutions made 

 up with ordinary distilled water, and with water which has 

 been more carefully purified. For the less pure water the 

 content of free iodine rises to a maximum in about four days, 

 and then gradually falls off again ; but with the purer water 

 the iodine content increases with the time for the first five days 

 and then remains constant for the next six weeks during which 



