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SCIENCE 



[N. S. Vol. XXVI. No. 659 



comparable with that of the northern 

 hemisphere, and consequently one welcomes 

 with enthusiasm the proposal on the part 

 of the Carnegie Institution to establish a 

 meridian observatory in a suitable situa- 

 tion in the southern hemisphere. Such an 

 observatory, energetically worked, with due 

 attention to all necessary precautions for 

 the exclusion of systematic errors, would 

 conduce more than anything else to remedy 

 in some degree that want of balance of 

 astronomical effort in the two hemispheres 

 to which allusion has already been made. 

 But in designing the program of the 

 work it should be borne in mind that the 

 proper duty of the meridian instrument in 

 the present day is no longer to determine 

 the positions of ali stars down to a given 

 order of magnitude, but to determine the 

 positions of stars which are geometrically 

 best situated and of the most suitable 

 magTiitude for measurement on photo- 

 graphic plates, and to connect these with 

 the fundamental stars. For this purpose 

 the working list of such an observatory 

 should include only the fundamental stars 

 and the stars which have been used as 

 reference stara for the photographic plates. 



Such a task undertaken by the Carnegie 

 Observatory, by the Cape, and if possible 

 by another observatory in the southern 

 hemisphere, and by three observatories in 

 the northern, would be regarded by astron- 

 omers of the future as the most valuable 

 contribution that could be made to as- 

 tronomy of the present day. Taken in 

 conjunction with the astrographie survey 

 of the heavens now so far advanced, it is 

 an opportunity that if lost can never be 

 made good; a work that would grow in 

 value year by year as time rolls on, and 

 one that would ever be remembered with 

 gratitude by the astronomei-s of the future. 



But for the solution of the riddle of the 

 universe much more is required. Besides 



the proper motions, which would be derived 

 from the data just described, we need for 

 an ideal solution to know the velocity in 

 the line of sight, the parallax, the magni- 

 tude, and the spectrum-type of every star. 



The broad distinction between these 

 latter data and the determination of proper 

 motion is this, that whereas the observa- 

 tions for proper motion increase in value 

 as the square of their age, those for velocity 

 in the line of sight, parallax, magnitude, 

 and type of spectrum may, for the broader 

 purposes of cosmical research, be made at 

 any time without loss of value. We should 

 therefore be most careful not to sacrifice 

 the interests of the future by immediate 

 neglect of the former for the latter lines of 

 research. The point is that those observa- 

 tories which undertake this meridian work 

 should set about it with the least possible 

 delay, and prosecute the program to the 

 end with all possible zeal. Three observa- 

 tories in each hemisphere should be suffi- 

 cient; the quality of the work should be of 

 the best, and quality should not be sacri- 

 ficed for speed of work. 



But the sole prosecution of routine labor, 

 however high the ultimate object, would 

 hardly be a healthy condition for the as- 

 tronomy of the immediate future. The 

 sense of progress is essential to healthy 

 gi'owth, the desire to know must in some 

 measure be gratified. We have to test the 

 work that we have done in order to be sure 

 that we are working on the right lines, and 

 new facts, new discoveries, are the best 

 incentives to work. 



For these reasons Kapteyn, in consulta- 

 tion with his colleagues in different parts 

 of the world, has proposed a scheme of re- 

 search which is designed to afford with- 

 in a comparatively limited time a great 

 augmentation of our knowledge. The 

 principle on which his program is based 

 is that adequate data as to the proper mo- 



