2 THE INFLUENCE OF RADIUM ON THE 



Other forms of radiant energy whose eti'ects on chemical 

 action have been investigated are ultra violet light, Rontgen 

 rays and radium radiations. 



Only a comparatively small amount of work has been car- 

 ried out on the effect of radium on chemical reactions. Hardy 

 and Wilcocks^ have investigated the oxidation of iodoform when 

 acted on by Rontgen rays and by radium, and Hardy' has ob- 

 served the coagulation of globulin under the influence of the 

 latter. Becquerel' found that white phosphorus is changed into 

 the inactive red phosphorus, and that mercuric chloride in the 

 presence of oxalic acid is reduced to mercurous chloride by the 

 radiations from radium. The Curies'* have shown that the rays 

 from radium change oxygen into ozone and discolour glass. 

 Berthelot" cites the following cases : iodic acid is decomposed 

 by radium rays and by light, with liberation of iodine, this 

 change being much slower than that of iodoform ; nitric acid 

 gives ofl" nitrous fumes when acted on by radium rays and by 

 light. These, as far as I have been able to discover, are all the 

 reactions that have been investigated up to the present time. 



These investigations have been mainl}' of a qualitative 

 nature, the quantitative side receiving very little attention. The 

 following experiments were carried on with a view to finding 

 out whether a ([uantitative examination of the caange, if any, 

 produced in hydriodic acid by the presence of radium would 

 throw light on the part played by the rays in this decomposi- 

 tion. Hydriodic acid was chosen on account of its instability; 

 and from its behaviour under the influence of light, it was 

 believed that it would be aflected by radium rays. 



The effect of light on the decouiposition of hydriodic acid 

 has, in the last few years, been largely investigated. Pinnow **, 



1. Proc. Roy. Soc. 72, 480, 200. 



2. Proc. Phys. J^oc, 1903, May 16. 



3. C. R.,1901, 1.3.3, p. 709. 



4. C. K., 18f>9, 12!», p. 823. 



5. (;. R.. 1901, 1.3.3. p. 659. 



6 Ber. (i. dent Chein. Ges., 1901, 34, 2528. 



