REPORT OF THE PRESIDENT, 1921. 5 



It is doubtful whether any recent discovery in the physical 



sciences has attracted wider interest or has contributed more to 



. ^ , , . the ultimate possibilities of astronomical and 



An Epoch-making , , ^ 



Discovery in physical scienco than the measurement of 

 s ronomy. (iiameter of a fixed star carried out at Mount 

 Wilson Observatory three daj^s subsequent to the annual 

 meeting of the Institution last year. This long-desired result 

 was made possible by many years of development of plant and 

 technique, together with the extraordinary skill of Dr. Michelson 

 and his associates and the clear \^sion of Dr. Hale in bringing 

 together all of the elements required for this particular task. 

 Measurement of the diameter of the star Betelgeuse once accom- 

 plished, the dimensions of other stars foUowed quickly. More 

 recently, by refinement of the original method, Dr. Michelson 

 has opened the way for corresponding observations on a group 

 of stars which seemed to be entirely out of range in the first 

 use of the interferometer on the 100-inch telescope. The 

 results already accomplished give confirmation of much impor- 

 tant work done by other astronomers and furnish a new starting- 

 point for a great variety of investigations concerning the nature 

 of the universe. In consideration of the critical problems which 

 are now at the front for discussion, provision has been made for 

 securing assistance and cooperation of other investigators. The 

 work of Dr. H. N. Russell, of Princeton University, which has 

 added much to an understanding of the evolution of the stars, 

 is fortunately now associated with that of Dr. Michelson and 

 others in helping to solve the special problems to which Mount 

 Wilson Observatory has given attention. 



A significant event in the operations of the Institution is the 

 completion within this year of a survey of the seas of the world 



Com letion of ^^ ^^^ noii-magnetic ship Carnegie. Launched 

 major work of the in 1909, this unique vessel has vo3^aged nearly 



s ip araegie. 3QQ QQQ niiles, covering the principal areas of the 

 great oceans and securing previously unavailable data on mag- 

 netic conditions which, with those obtained by concurrent studies 

 on land, give a map of magnetic variations not heretofore possible. 



