MOUNT WILSON SOLAR OBSERVATORY. 231 



measured and reduced for radial velocity; she has computed the 

 absolute velocities for about GO stars of known parallax. The work 

 relating to laboratorj^ investigations included the measurement of 

 photographs made by Mr. Gale at Chicago with the apparatus for- 

 merly used in the Pasadena laboratory to determine the shift of iron 

 lines at low pressures. In connection with this, plates taken by Mr. 

 Babcock covering the same region have been measured for the deter- 

 mination of the Zeeman effect. Several test plates for the 100-inch 

 mirror were measured and also a few laboratory plates made for the 

 determination of the Zeeman effect for chromium. 



Mrs. Nichols has given much time to identifications and measures 

 upon laboratory photographs of spectra, 124 plates having been 

 examined and measured. In addition she has measured 23 stellar 

 photometric plates and has assisted in the related reductions. She 

 has also made extensive measures for screw-tests of seven compara- 

 tors, and, in addition to general computing, assisted for about three 

 months with the reductions of tertiary standards of wave-length. 



Miss Myrtle L. Richmond was appointed to the division July 1, 

 and thus far has been engaged with the measurement and reduction 

 of photometric plates. 



Miss Shumway has given her time wholly to recording and reduc- 

 tions connected with the investigations in stellar spectroscopy. 



The measurement and reduction of the plates regularly made with 

 the 5-foot spectroheliograph have remained in the hands of Miss 

 Smith. The areas of the calcium flocculi on 258 spectroheliograms 

 have been determined and 331 prominence plates have been meas- 

 ured. All reductions, including the fluctuation curves of the calcium 

 flocculi, are complete to August 1, 1913. Miss Smith has made 502 

 prints of spectroheliograms, and about 400 other prints, the greater 

 part of which are of the Selected Areas. She has also given some 

 time to a detailed study of the structure of sun-spots, including the 

 history, peculiarities, etc., of individual spots and groups. 



Miss Mabel Van Deusen joined the division on August 1, and at 

 present is engaged with star-counts upon photographs of clusters. 



As during the preceding year. Miss Ware has been occupied mainly 

 with work connected with the solar investigations of Mr. St. John. 

 Many measures have been made on solar spectrograms for the deter- 

 mination of radial motion in sun-spots, and a large number of labo- 

 ratory photographs have been measured and reduced for the purpose 

 of determining tertiary standards of wave-length and testing the 

 precision of wave-lengths measured with plane gratings. Miss Ware 

 is at present engaged upon an extended series of measures for the 

 comparison of arc and solar spectra. 



Miss Haines continued as librarian until January 20. Since that 

 date she has been on leave. Miss Burwell served until May 1, and 



