MOUNT WILSON SOLAR OBSERVATORY. 233 



Charles E. St. John has given special attention to the supposed 

 mutual influence of closel}^ adjacent solar lines, and the question of 

 possible anomalous dispersion in the sun. Professor G. W. Ritchey 

 has completed the 100-inch mirror and made some photographs of 

 nebulae with the 60-inch reflector. Dr. J. A. Anderson, who joined the 

 Observatory staff in July, is engaged in a study of the Stark effect and 

 is collaborating with Mr. Jacomini in the ruling of gratings. Mr. 

 Harold D. Babcock has continued his researches on the Zeeman effect 

 and the determination of standards of wave-length by interference 

 methods. Mr. Ferdinand Ellerman has served as Observatory 

 photographer and carried on his work with the Snow and tower 

 telescopes. Mr. Francis G. Pease, in charge of instrument design, 

 has given much time to the IGO-inch telescope and has continued photo- 

 graphic and spectroscopic studies of nebulce. Dr. Harlov/ Shapley 

 has pursued his studies of stellar photometry, star clusters, and 

 variable stars, and devoted special attention to the spectroscopic 

 phenomena of the Cepheids. Dr. Adriaan van Maanen has carried 

 forward his determinations of stellar parallaxes and proper motions 

 and the measurement of spectra to fix the position of the sun's magnetic 

 axis; he has also studied the internal motions in spiral nebulae. Dr. 

 Walter Colby returned to the University of Michigan in September, 

 after spending a year at the Observatory. Mr. George P. Luckey, 

 after completing his observational and experimental work, resigned 

 his position on November 1. Dr. Seth B. Nicholson, who joined the 

 Observatory staff September 1, has devoted most of his time to solar 

 work. Professor Alfred Joy, who joined the staff October 1, has 

 also been engaged in the solar work. Mr. George S. Monk, whore- 

 signed his position on October 1, has assisted in the stellar spectroscopic 

 investigations. 



Professor J. C. Kapteyn, Research Associate of the Carnegie Insti- 

 tution of Washington, has continued in Holland his studies of Mount 

 Wilson observations. Professor R. W. Wood, of Johns Hopkins Uni- 

 versity, spent a few days on Mount Wilson in October, photographing 

 the Moon, Jupiter, and Saturn through color screens. 



Miss Janet Howell, who held the Sarah Berliner Fellowship for 

 1915-1916, spent the academic year at the Pasadena Laboratory 

 studying the Stark effect for lithium and calcium. Miss Edna Carter, 

 of Vassar College, has recently been at work in the Pasadena Labora- 

 tory on spectra produced in vacuum tubes by the cathode discharge. 

 Dr. Gustaf Stromberg, of Stockholm University, joined the staff in 

 June as a volunteer assistant in stellar spectroscopy. 



Dr. Charles G. Abbot, Director of the Smithsonian Astropbysical 

 Observatory, has continued his solar investigations on Mount Wilson 

 during the summer of 1916 with the assistance of Mr. L. B. Aldrich. 



