106 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1925 



Mr. E. E. Smith was employed on the private roll as assistant at 

 Harqua Hala from February 9, 1925. 



^Ir. A. J. Ahearn assisted Doctor Abbot on Mount Wilson during 

 the expedition of 1924. 



SUMMARY 



Much progress in the study of the variation of the sun and its ap- 

 plication to weather forecasting has been made, as reported in pub- 

 lications Nos. 5, 6, and 7 of Volume 77, Smithsonian Miscel- 

 laneous Collections. Improvements in apparatus and methods de- 

 signed to add to the accuracy of solar radiation measurements, and 

 to make possible a valuable revision of existing values, are on foot. 

 The station at Harqua Hala, having proved somewhat disappointing, 

 is being removed to Table Mountain, in California, about 2,000 feet 

 higher, but much more accessible. The solar cooker has been greatly 

 improved. Measurements of atmospheric ozone are in progress. 

 New devices were tried in stellar energy spectrum measurements and 

 the way seems clear for great advances in that line. 



Kespectfully submitted. 



C. G. Abbot, Director. 



Dr. Charles D. Walcott, 



Secretary, Smithsonian Institution. 



