208 REPORTS ON INVESTIGATIONS AND PROJECTS. 



with other stars all those that are readily visible to unassisted vision from 

 the north to the south pole. 



The greater part of the work done here during the past year has related 

 to the various operations for completion of the Preliminary General Catalog 

 of something over 6,000 stars, to which allusion has been made in former 

 reports. In the interests of the entire work it has been necessary to com- 

 pute first the positions and motions of several thousand stars that have been 

 most generally and accurately observed in the last century. These results 

 being now available, it was seen that an extension of the list to include 

 about 2,000 additional stars would furnish a catalog essentially complete 

 for all the stars ordinarily visible to the unassisted eye. Several hundreds 

 of these were urgently in need of reobservation. While this reobservation 

 would constitute something of an interruption of the regular program, it 

 was thought to be worth while, in view of the end to be gained. Since the 

 completion of the entire work planned for the Department of Meridian 

 Astrometry can not well be brought about within less than nine or ten years, 

 it seemed very desirable that practical astronomers, as well as investigators, 

 should have the use of such a work as this Preliminary General Catalog 

 without the delay which would be entailed by reserving publication until 

 the completion of the entire work. This catalog might have been offered for 

 publication a year ago if it had been restricted to the four thousand best- 

 determined stars ; but the advantage of essential completeness as to the lucid 

 stars, and as to both hemispheres, rendered possible by the cooperation of 

 the Royal Observatory at the Cape of Good Hope, seemed to justify the 

 disturbance of general plan and the vigor of effort implied. 



Accordingly, the positions of 740 stars of the Preliminary General Catalog 

 have been determined by observations at the Dudley Observatory during the 

 past year. With few exceptions, each has been observed four times, in a 

 few instances eight times. All these observations have been completely 

 reduced in duplicate and formed into a catalog which includes in all 1,112 

 stars. These results have been already incorporated in the equations which 

 had been formed for determination of positions and motions for the Prelimi- 

 nary General Catalog, and within a few weeks the solution of these equa- 

 tions for all stars of the Catalog north of — 36° should be definitive for present 

 purposes. 



As explained in my report of last year. Sir David Gill, astronomer royal 

 at the Cape of Good Hope, has undertaken the reobservation of about 1,100 

 stars south of — 36° of declination. Within two weeks I have learned from 

 him that the work of observation on these stars, begun September 26, 1905, 

 was brought to completion on August i of the present year. The compu- 

 tations are practically complete. The greater part of the results has already 

 been received here. The cooperation of the Cape Observatory in the fur- 



