4 ROYAL SOCIETY OF CANADA 



such as the change in width of the spectral line brought about by dif- 

 ferent conditions of temperature, pressure, etc., operating on the same, 

 this method would find a very practical application. It should there- 

 fore be of special service in following such modifications in the con- 

 stitution of radiating atoms as are brought into evidence by changes 

 in their spectral lines. 



