REPORT OF COMMITTEE ON OBSERVATORIES 20. 



pendent research and for the bearing it has on other works, including 

 those here proposed. 



In this line of work, as in nearly all other departments of astron- 

 omy, contributions from the southern hemisphere have always been 

 deficient. With a few notable exceptions, there has been a lack of 

 highly trained and experienced astronomers there. The recent ef- 

 forts of the Cape Observatory in this line have been both skillful and 

 energetic ; but the Cape Observatory alone is unable to offset the 

 numerous observatories in the northern hemisphere engaged in the 

 precise observation of standard stars. The result is that the weight 

 of our knowledge of the positions and motions of the standard stars 

 in the northern sky is fully five times that for the far southern sky. 

 A single corps of observers transferred from the northern hemi- 

 sphere, where its loss would not be a relatively serious matter, to the 

 southern hemisphere, where its services are so much needed in this 

 line, could reduce the existing discrepancy of weight in fundamental 

 determinations for the present epoch by one half. 



It has been conclusively shown that the exactness of our knowl- 

 edge of general drift in the motions of the stars, whether it arises 

 from solar motion, rotation, or from any other source, depends 

 almost wholly upon the number and precision of our fundamental 

 determinations of the positions of the standard stars. The main 

 battle is fought on this field. Furthermore, astronomy has now 

 arrived at the point where, by comparatively little additional obser- 

 vation, it will be possible to compute the motion of nearly every 

 star brighter than the seventh magnitude in the northern sky with 

 a fair degree of accuracy. With the observations herein proposed, 

 the same thing, in a modified degree, would be true of the stars in 

 the southern hemisphere. Not many more than one third of these 

 stars has been reobserved during the last quarter of a century. 

 This work accomplished, astronomers could hope to deal success- 

 fully with problems of motion for all the stars visible without a 

 telescope, and beyond that for all stars down to those which are 

 one third as bright as the faintest visible to the ordinary eye — about 

 15,000 stars in all. This would give us the first opportunity ever 

 offered for a comprehensive discussion of the solar motion and re- 

 lated problems on a scientifically correct basis, with a liberal supply 

 of material distributed over the entire sphere. 



This work would, therefore, possess a high scientific interest as 

 an end in itself ; but it would also serve as an indispensable basis 

 for the observation of planets and of the fainter stars. A scheme 



