110 ANNUAL REPOET SMITHSONIAN INSTITUTION, 1924 



solar changes, have been regularly submitted by Mr. H. H. Clayton 

 for certain periods of time in advance. Revision of the solar radia- 

 tion results of the two stations shows average daily accord to less 

 than 0.5 per cent in their solar-constant determinations. Observa- 

 tions have been received from one or both solar-radiation stations 

 on about 90 per cent of all days. Further experiments with the solar 

 cooker have resulted in some advancement and have pointed the way 

 to further progress. Apparatus has been made ready for determina- 

 tions of atmospheric ozone after the method of Fabry and Buisson. 

 Highly interesting results on stellar energy spectrum distribution and 

 on star diameters have been obtained with a Nichols radiometer in co- 

 operation with the Mount Wilson Observatory of the Carnegie Insti- 

 tution. 



Respectfully submitted. 



C. G. Abbot, Director. 



Dr. Charles D. Walcott, 



Secretary., Smithsonian Institution. 



