Hart — Action of Light on Magnetism. 73 



1. An effect of light on magnetism is, in general, easily 

 obtained and depends only on a certain condition of sensibility 

 artificially produced. 



2. This condition is, apparently, that a peculiar and unstable 

 distribution of the magnetic lines of force shall exist in the 

 magnet. 



3. The action is, in general, a purely mechanical one, similar 

 to the effect of a blow. 



4. Evidence of the magnetic action of polarized light has 

 probably been obtained by the use of iron films on glass. 



In conclusion, I wish to thank Prof. A. W. Wright for his 

 assistance throughout the investigation. He suggested the 

 subject and general plan of research, and afforded me ample 

 facilities for performing the experiments. 



Sloane Physical Laboratory, June 15, 1900. 



