DEPARTMENT OF MERIDIAN ASTROMETRY. 215 



observing list for the meridian circle which shall include one star per 

 square degree. It is desirable to select stars, as far as possible, with 

 kno^vTi spectral type and with a sufficient number of observations 

 taken in the past to insure the determination of a very approximate 

 proper-motion; but it is also desirable to select stars from the lists 

 of the Carte du Ciel. Those stars which are contained in the General 

 Catalogue are given the preference. They have been plotted to 

 facilitate making a choice. Likewise the stars contained in the new 

 Draper Catalogue are plotted as far as published. In some regions 

 where there are gaps it will be necessary to step outside the adopted 

 limits of magnitude in order to secure the desired symmetrical dis- 

 tribution, but the percentage of such cases to the total number of stars 

 involved is very small. 



Preparations have been completed for an expedition to aid in the 

 selection of an observing-site, as the climate at Albany is not favorable 

 for such a project as is contemplated. A o-inch photographic doublet 

 lens of 13 feet focal length was kindly loaned by the Mount Wilson 

 Observatory, and has been mounted on a telescope specially designed 

 to meet the requirements of transportation. It is intended to test the 

 relative conditions of seeing at various stations by comparison of star- 

 trails taken at different altitudes. The preliminary tests at Albany 

 were entirely satisfactory. 



A survey of the U. S. Weather Bureau reports for the entire United 

 States leads to the investigation of two regions — the south Atlantic 

 States and Arizona. While the western conditions are in general more 

 favorable than those in the East, there is a large diurnal range in tem- 

 perature to be found in any desert region, as well as a large annual range. 

 The distribution of clear weather appears to be fairly uniform in the 

 Southeastern States, and it is amply sufficient for the requirements, 

 while the diurnal range in temperature is favorable to good seeing. 



STAFF. 



The Director was absent for a portion of the year in attendance upon 

 the meeting of the International Research Council at Brussels. He 

 has continued his investigation of stellar parallaxes and has devoted 

 considerable time to the problems arising out of the proposed future 

 work of the Department. Dr. Sebastian Albrecht has continued 

 his investigation of standards of wave-length, and has also been occu- 

 pied with the spectral variation in Cepheids. Some time has also been 

 devoted to the new project. Mr. Sherwood B. Grant has been absent 

 in the naval service as marine engineer. Mr. Heroy Jenkins has been 

 largely occupied in deriving the systematic corrections to catalogues 

 received during the last few years. Mr. Harry Raymond has been 

 occupied with many departments of the work. Mr. Arthur J. Roy, 

 as formerly, has supervised the reduction and discussion of the observa- 



