MOUNT WILSON OBSERVATORY. 187 



gations in stellar spectroscopy. Professor Frederick H. Seares, super- 

 intendent of the Computing Division and editor of the Observatory 

 pubhcations, has continued his work in connection with the reduction 

 of solar magnetic observations and his researches in stellar photometry'. 

 Dr. Arthur S. King, superintendent of the Physical Laboratory, has 

 divided his time between investigations for the Navy and the con- 

 tinuation of his work with the electric furnace. Dr. Charles E. St. 

 John has di\dded his time between the spectrographic study of the 

 solar rotation and the determination of solar and laboratory wave- 

 lengths of iron lines. Professor G. W. Ritchey has completed the 

 optical parts of the 100-inch reflector and continued the photography 

 of nebulae with the 60-inch. He has also undertaken extensive optical 

 work for the Ordnance Department of the Army. Dr. J. A. Anderson 

 has given all his time to war service, including the designing and testing 

 of special micrometers constructed in our instrument shop for the 

 Bureau of Standards, and experimental researches for the Navy. 

 Mr. Harold D. Babcock, in addition to his work for the Navy 

 with Dr. Anderson, spent a part of the year at the Washington 

 office of the National Research Council. Mr. Ferdinand Ellerman 

 has continued his solar observations and his work as Observatory 

 photographer. Mr. Francis G. Pease continued his work of instrument 

 design and his photographic work on nebulae and star-clusters until 

 March, when he went to Washington to occupy the position of chief 

 draftsman in the office of the National Research Council. Dr. Harlow 

 Shapley has been engaged in investigations of star-clusters, variable 

 stars, and researches in stellar photometry. Dr. Adriaan van Maanen 

 has continued his measurement of spectra to fix the position of the 

 sun's magnetic axis, and has carried forward his determinations of 

 stellar parallaxes. Dr. Seth B. Nicholson has given most of his time 

 to solar observations. Professor Alfred Joy, who has collaborated 

 with Dr. Adams in stellar spectroscopic work, has also taken part in 

 the solar observations. Dr. Gustav Stromberg has devoted most of 

 his attention to a study of the correlation between stellar absolute 

 magnitude and radial velocity, solar motion, and stream motion. Dr. 

 Roscoe F. Sanford, who became a member of the staff in January, 

 has given all his time to stellar spectroscopy. Mr. Arthur S. Dockham 

 continued his work in connection with the solar observations until 

 June, when he left the Observatory to join the National War Work 

 Council of the Young Men's Christian Association in France. 



Professor J. C. Kapteyn, who retains his position as Research 

 Associate of the Carnegie Institution, has contuiued his investigations 

 in Groningen. 



The members of the Computing Division have assisted in the work 

 of the various departments as follows: Miss Ware and Miss Miller 

 have been engaged with the solar investigations carried on by Dr. 



