i62 re;ports of investigations and projects. 



of the Snow and tower telescopes. Dr. C. E. St. John has been engaged in an 

 investigation of the radial motion of the calcium vapor in the solar atmos- 

 phere. He has also studied the elliptical polarization produced by the mir- 

 rors of the tower telescope, and has made some of the daily photographs of 

 the sun with the 5-foot spectroheliograph. Mr. H. D. Babcock, formerly 

 of the National Bureau of Standards, who was appointed a member of the 

 staff on February i, has been occupied principally with stellar photography 

 and spectrographic observations with the 60-inch reflector. Dr. E. A. Fath, 

 formerly of the Lick Observatory, began work on July i. He will devote 

 most of his time, for the present, to a photographic study of the spectra of 

 nebulae and star-clusters and a spectrographic survey of stars in Kapteyn's 

 Selected Areas. Dr. C. M. Olmsted has continued his laboratory work in 

 Pasadena. Mr. W. I. Way has assisted in making the daily series of photo- 

 graphs with the 5-foot spectroheliograph. Miss Ware, Miss Lasby, Miss 

 Smith, Miss Burwell, and Miss Wickham have continued the measurement 

 of photographs and the other duties of the computing division. Miss E. 

 Phoebe Waterman joined the computing division on January i. 



Prof. J. C. Kapteyn, of the University of Groningen, Research Associate 

 of the Carnegie Institution of Washington, spent three months on Mount 

 Wilson in the autumn of 1908 and returned in July, 1909, to continue his 

 work. Dr. H. G. Gale, Assistant Professor of Physics at the University of 

 Chicago and Research Associate of the Carnegie Institution of Washington, 

 began an investigation of the spark-spectra of metals under pressure, in 

 connection with the spectrum of the sun's limb, in March, 1909. Prof. 

 Ernest F. Nichols, Research Associate of the Carnegie Institution of Wash- 

 ington, had expected to spend the summer of 1909 on Mount Wilson. He 

 was prevented from doing so, however, because of his appointment as presi- 

 dent of Dartmouth College. Dr. Giorgio Abetti, of the Osservatorio di 

 Arcetri, Florence, spent five months on Mount Wilson during the winter 

 and spring of 1909, as a volunteer assistant engaged chiefly in solar research. 

 Mr. Kristian Lows, of Copenhagen, stayed several weeks on Mount Wilson 

 during the summer of 1909, assisting in computing, etc. Dr. C. W. Cham- 

 berlain, Professor of Physics at Vassar College, carried on special research 

 at the Mount Wilson laboratory during August, 1909. 



During the autumn of 1908 a permanent concrete building was erected 

 by the Smithsonian Institution on a piece of our property on Mount Wilson, 

 leased by the Carnegie Institution of Washington for that purpose. In this 

 building all of the instruments, formerly used by Mr. Abbot and his assistants 

 in temporary structures, are now mounted. The work of the Smithsonian 

 Expedition during the present season was begun by Mr. Abbot in May and 

 will continue until November. Dr. Leonard R. Ingersoll, Assistant Pro- 

 fessor of Physics at the University of Wisconsin, has assisted Air. Abbot 

 in making the observations. 



