296 Scientific Proceedings^ Royal Dublin Society. 



effects of the rays. This is justified by the fact now ascertained tliat the X 

 and 7 rays are similar in character to light-waves, although of a wave-length 

 some ten thousand times less. This discovery makes the use of j rays con- 

 tinuous with that of the Finsen light. Tliey represent a much less easily 

 absorbed luminosity proceeding from the radioactive substance as from a 

 lamp : but a lamp so constituted physically as to meet therapeutic conditions 

 in an extraordinary degree. 



IvEAGH Geological Laboratory. 



