22 W. B. Cartmcl 



be applied to those radiaticns which are strongly absorbed by the 

 fuchsin, he obtained only the four values given above. In order 

 to make a comparison with Walter's work, Pfliiger measured the 

 same four quantities directly, using the difference in transmission 

 of two films of different thickness. 



In conclusion, my best thanks are due Professor Brace for 

 help and encouragement througliout the work, and for the excel- 

 lent laboratory facilities afforded me at the University of Ne- 

 braska, where the work was done. I must also thank Professor 

 B. E. Moore for various courtesies extended to me, and for sug- 

 gestions in regard to the photometric measurements. 



T2« 



