1 66 CARNEGIE INSTITUTION 



Where natural competition is absent or periods of phenomena are 

 long, there is a grand opening for a powerful combined attack. One 

 may count, for instance, on special studies of solar rotation at exist- 

 ing observatories, simply because the period is short, but probably 

 the variation of such short period phenomena in the eleven year 

 period could only be properly tackled in an observ^atory where the 

 outsetting aim was the stud}- of secular phenomena. 



Hence it seems to me that secular phenomena are the special 

 province of such an observ^atory as you are contemplating ; and it 

 would seem a wiser course to concentrate attention on such observ'a- 

 tions as would have direct bearing on these, and to provide for a 

 systematic discussion of observations already accumulated, as well 

 as for a systematic study of phenomena in process of being observed, 

 than to scatter forces on the study of many stellar problems. 



In many ways probably more advance could be made by enabling 

 a single observer to carry out his observations in several stations 

 successively. The solar radiation "constant" is an instance in 

 point. Considerations of this sort would lead me to think that in 

 some ways it might be better policy not to lock up huge capital in 

 one fine observatory outfit, but rather to help individual researches 

 by providing means for having them carried on with, say, one or two 

 complete outfits that could be moved to various points of the globe. 



As I say, I hesitate to commit these remarks to paper. I suspect 

 you are far beyond the elementary stage that these remarks refer to. 



As to aims and researches, your program is a large one already. 

 It is not clear to me why it should not include a new attack on 

 magnetic disturbances, and possibly on atmospheric and electrical 

 phenomena. 



\Froyn Dr. Ralph Copela7id, Astronoiner Royal, Royal Observatory, 



Edi7ibicrgh.~\ 



August 15, 1903. 



I am afraid you will think me remiss in only now repl^dng to your 

 letter of March 26 ; but I have indeed most carefully thought over 

 your project and looked up my old papers on mountain observato- 

 ries. I have not much to add to the views which I expressed in my 

 paper on the subject in volume III of Copernicus, which you have ; 

 but, when consulting it, kindly substitute on page 230, line 22, 1.32 

 inch for 0.7 inch. 



Another note on my South American trip, written for the British 



