lo Fred J. Bates 



seems to be the simplest method of keeping the luminosity curve 

 unchanged. The elimination of these effects should in many 

 cases bring about a more perfect agreement, especially for solu- 

 tion of the measurements of different investigators on the rota- 

 tion of plane polarized light, both natural and magnetic. 



The opportunity is here taken to thank Professor D. B. Brace 

 for his helpful suggestions. 



264 



