MOUNT WILSON SOLAR OBSERVATORY. 201 



STAFF. 



A return of his previous illness required the Director to be absent 

 from the middle of March until early in August. During the rest 

 of the year he has devoted as much time as could be spared from other 

 duties to the study of the general magnetic field of the sun. 



Dr. Walter S. Adams, to whom the Director is indebted for much 

 valuable aid, was appointed Assistant Director in January. During 

 the Director's absence he was in charge of the Observatory, and 

 throughout the year he has continued at the head of the department of 

 stellar spectroscopy. Professor F. H. Scares has remained in charge 

 of the Computing Division and the editorial work, and has continued 

 his researches in stellar photometry. He has also completed a theo- 

 retical study of the general magnetic field of the sun and prepared an 

 extended report on the present state of the photographic process. 

 Dr. Arthur S. King has continued his investigations as superintend- 

 ent of the physical laboratory, devoting most of his time to problems 

 connected with the electric furnace. Dr. Charles E. St. John has 

 extended his spectroscopic work on the sun with the 150-foot tower 

 telescope, and has also pushed forward his study of the secondary 

 standards of wave-length in the spectrum of iron. Mr. Ferdinand 

 Ellerman has devoted most of his time to observational work with 

 the 150-foot tower telescope in connection with the general magnetic 

 field of the sun. Mr. Ellerman, Dr. Adriaan van Maanen, Mr. 

 Charles S. Backus, and Mr. Walter T. Whitney have carried on the 

 dailj' observations of the sun with the 5-foot spectroheliograph. 

 ]\Ir. H. D. Babcock has pursued his laboratory investigations 

 with special reference to the Zeeman effect and the wave-lengths of 

 the arc lines. Mr. F. G. Pease has continued his systematic photo- 

 graphic study of nebulae and star clusters with the 60-inch reflector 

 and has also made some photographs of these objects with a new 

 low-dispersion spectrograph, in addition to his work of instrument 

 designing. Dr. Arnold Kohlschiitter returned to the Observatory 

 the latter part of April, after an absence of six months in Germany, 

 and has devoted most of his time to stellar spectroscopic observations 

 and the classification of stellar spectra. Dr. van Maanen, who 

 joined the stafT September 1, 1912, has measured all of the photo- 

 graphs of spectra taken for the study of the general magnetic field of 

 the sun. He has also assisted in the stellar spectroscopic work during 

 the absence of Doctor Kohlschiitter. Mr. Backus resigned from the 

 Observatory stafT December 1, 1912. Mr. WTiitnej^ who joined the 

 staff February 15, 1913, as assistant in both stellar and solar work, 

 resigned his position August 15, to pursue further studies in the Uni- 

 versity of Chicago. 



Professor J. C. Kapteyn, Research Associate, has spent several 

 months on Mount Wilson, continuing his studies of star-streams and 



