REPORT OF THE PRESIDENT, 1914. 25 



Attention is invited to an interesting section of the Director's 

 report devoted to a summary of the work accompHshed by the 

 department during the first decade of its existence. This sec- 

 tion is instructive in showing that a decade is the smallest con- 

 venient unit of time for adequate estimation of the activities of 

 such an establishment. It appears that during this decade 49 

 investigators have made use of the Tortugas Laboratory, 28 of 

 these having returned two or more times, making a total of 

 108 visits to this relatively inaccessible center of research. Of 

 the publications emanating from the department, 60 have been 

 published by the Institution, while upwards of 40 have been 

 published under other auspices; the Institution has issued 2,551 

 printed pages and 269 plates exclusive of annual reports appear- 

 ing in the Year Books. 



The activities of the Department of Meridian Astrometry 

 are concentrated on the derivation of stellar positions for the 

 comprehensive catalogue in preparation, on sup- 

 Meridian plementary measurements of stellar coordinates 

 s rome ry. ^.^j^ ^^^^ meridian circle of the Dudley Observa- 

 tory, and on investigations of residual stellar motions. The 

 latter have now become the most important element in the def- 

 inition of stellar positions by reason of the extraordinary recent 

 progress in sidereal astronomy, to which the Department has 

 contributed in large degree. Thus, along with the formidable 

 computations required by the large mass of observations made by 

 the Department at San Luis, Argentina, researches are simul- 

 taneously continued on the problems of star-drift, including the 

 speed and direction of motion of our solar system. In the mean- 

 time, the catalogue is progressing favorably and some portions 

 of the observatory list of miscellaneous stars are approaching 

 com.pletion, although cloudiness during the past two winters 

 has interfered with this part of the departmental program. In 

 the meantime, also, the manuscript of the zone catalogue of stars 

 whose positions were measured at the observatory during the 

 years 1896 to 1900 is undergoing the final process of comparison 

 and checking preparatory to publication. 



