DEPARTMENT OF MERIDIAN ASTROMETRY. 213 



Mr. Wilson has computed the orbits of three spectroscopic binaries 

 I Carinse (interesting because of its being a Cepheid with a period of 

 35.5 days), ,8 Doradus, and 6 Sagittarii. 



The Director, accompanied by ]Mr. Wilson, left in August 1920 

 for the southwest to test observing conditions in that region. Mount 

 Wilson, Mount Hamilton, and the region around San Diego were 

 visited in California; Tucson, Prescott, and Flagstaff, in Arizona; 

 and Albuquerque and Santa Fe in New Mexico. The tests were car- 

 ried on by means of star trails taken with a 5-inch photographic 

 doublet of 13 feet focal length, the same instrument used in an ex- 

 ploration of the South Atlantic States. 



It might be stated in general that the seeing conditions in the south- 

 west furnish no appreciable advantage over the conditions in the favor- 

 able region of the southeast described in the last annual report of this 

 Department. A distinct advantage, however, results for most classes 

 of observation through the greater number of clear nights per year 

 and, in the case of the desert regions, through the greater transparency 

 of the atmosphere. 



STAFF. 



The Director has been engaged on special researches. He under- 

 took an extensive investigation of the obser\dng conditions in the 

 southwestern States during the first thi'ee months of the j^ear. Dr. 

 Sebastian Albrecht continued his researches on standards of wave- 

 length. Mr. Sherwood B. Grant has been engaged on a number of 

 the processes of reduction in the formation of the catalogues. Mr. 

 Heroy Jenkins continued his work on the derivation of systematic 

 corrections to star catalogues. Mr. Harry RajTnond has assisted 

 the Director in the determination of the stellar space velocities and 

 has been also engaged with, many departments of the work. Mr. 

 Arthur J. Roy was in charge of the Department during the absence 

 of the Director. He has continued his supervision of the reduction 

 of the zenith-distances and has also supervised the computations for 

 the systematic corrections to star catalogues. Mr. William B. Varnimi 

 has devoted his energies toward a solution of the problem of the 

 diurnal variation in clock-rate. Dr. Ralph E. Wilson accompanied 

 the Director on his expedition to the southwest to observe climatic 

 conditions. He has also assisted the Director upon special investi- 

 gations and has undertaken a number of personal investigations. 

 Miss Alice M. Fuller has continued as secretary of the Department. 



As usual, the computing staff has been engaged on the various com- 

 putations involved in the reduction of observations and in the inves- 

 tigation of various problems. It has consisted of Miss Marion F. 

 Benjamin, Mrs. Lillian F. Blanchard, Miss Grace I. Buffum, Mrs. 

 Livia C. Clark, Miss Mary M. Kampf, Miss Isabella Lange, Miss 

 Marie Lange, and Miss Frances L. MacNeill, together with four 

 miscellaneous computers employed temporarily upon the work. 



