234 CARNEGIE INSTITUTION OF WASHINGTON. 



on September 1, has taken part in the solar observations and in the 

 work with thermopiles. Mr. W. P. Hoge, night assistant with the 

 60-inch telescope, has joined in the stellar spectroscopic observations. 

 Mr. Milton Humason, night assistant, has made photographic and 

 stellar spectroscopic obsei-vations with the 10-inch telescope and other 

 instruments. Mr. Edison Hoge has taken part in the solar observa- 

 tions and served as assistant photographer. Mr. Hugo Benioff assisted 

 during the summer in the solar observations and continued his experi- 

 ments with the thalofide cell. Mr. Sinclair Smith has been part time 

 assistant in the Pasadena laboratory throughout the year. 



Professor J. C. Kapteyn, now of the Leiden Observatory, Research 

 Associate of this Observatory, has continued his stellar investigations 

 in Holland. Professor A. A. Michelson, of the University of Chicago, 

 Research Associate, has continued at Mount Wilson his researches with 

 the interferometer and on the velocity of light, and has undertaken 

 there a study of the relative motion of the earth and the ether by a new 

 method. Professor Henry Norris Russell, of Princeton University, 

 recently appointed Research Associate, spent two months at the 

 Observatory, where he carried on a variety of studies dealing with the 

 Majorana gravitation effect, Saha's ionization theory, oxygen in plan- 

 etary atmospheres, and other subjects. 



Professor Dayton C. Miller, of the Case School of Applied Science, 

 repeated the Michelson-Morley experiment on Mount Wilson in the 

 spring. Dr. Harry 0. Wood, Research Associate of the Carnegie 

 Institution of Washington, began his seismological investigations in 

 Southern California with temporary headquarters at the Pasadena 

 office of the Observatory. 



Of the Computing Division, Miss Ware and Miss Miller have con- 

 tinued to assist Dr. St. John. Miss Burwell, Miss Brayton, Miss 

 MacCreadie, and Miss Shu m way have been engaged with the investi- 

 gations in stellar spectroscopy. Miss Richmond, Miss Joyner, and 

 Miss Mayberry have assisted Mr. Seares and Mr. Shapley in photo- 

 metric measures and reductions. Mrs. Marsh has assisted Mr. van 

 Maanen with trigonometric parallaxes and reductions of measures on 

 spiral nebulae, while Miss Keener has given her time to the work of 

 the Physical Laboratory. Miss Mayberry has also assisted the Direc- 

 tor, and Miss Brayton has given some time to the measurement of 

 laboratory spectrograms. Miss Connor has remained in charge of the 

 library and has aided with the editorial work. 



Mrs. Harlow Shapley, volunteer assistant, continued her work in 

 collaboration with Dr. Shapley. Messrs. Clyde R. Keith and F. L. 

 Hopper, of the California Institute of Technology, assisted Dr. Merrill 

 in his Laboratory studies during part of the year. Dr. K. S. Gibson, 

 of the U. S. Bureau of Standards, worked for a few weeks with the 

 Koch apparatus. 



