DEPARTMENT OF MERIDIAN ASTROMETRY.* 



Benjamin Boss, Acting Director. 



The Department of Meridian Astrometry has suffered a severe loss 

 during the period covered by this report (September 1912 to Sep- 

 tember 1913), through the death of its Director, Professor Lewis Boss, 

 on October 5, 1912. As the President of the Carnegie Institution of 

 Washington has incorporated a biography of Professor Boss in Year 

 Book No. 11, page 8, it will be sufficient here to say that he foresaw 

 a possible breakdown in time to prepare for it, so that the work of 

 the Department has suffered no check. 



INVESTIGATIONS. 



During the past year, aside from the prosecution of the general 

 scheme, considerable attention has been given to investigations 

 growing out of the published results or accumulated material. 



Professor Lewis Boss, in the Astronomical Journal, Nos. 623-624, 

 placed the apex of solar motion, as derived from the G or solar type 

 stars, at some distance from the apices derived from the solution of 

 other types. Professor Campbell, in the Lick Observatory Bulletin 

 No. 196, derived a smaller value for solar motion from his treatment 

 of G-type stars than the values obtained from his solution of other 

 types. The two phenomena seemed to indicate some real peculiarity 

 in the motions of the G-type stars. 



After hypothetically freeing the proper-motions from the effects 

 of solar motion, a solution was made to determine any residual drift 

 motion, the result indicating a preference of motion of the G-type 

 stars toward a point at right ascension = 272?7, dechnation =5?2, 

 in the ratio of 3 to 2. This would seem to indicate that the G-type 

 stars as a class are drifting toward what is commonly termed the 

 antivertex of preferential motion, or the apex of drift II, according 

 to Kapteyn's convention. The solution excluded proper-motions 

 exceeding 20 seconds of arc per century. Their inclusion would tend 

 to reduce the ratio above mentioned. This phenomenon, if further 

 confirmed by the inclusion of additional G-type stars, will bear an 

 important part in the derivation of solar motion. 



Another phenomenon which has been noted, and will receive 

 further attention, is th'; peculiar distribution of the apices of solar 

 motion as derived from the solution of the other types. 



*Addres3 Dudley Observatory, Albany, N. Y. Grant No. 864. $25,180 for investi- 

 gations during 1913. (For previous reports see Year Books Nos. 2-11.) 



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