REPORT OF COMMITTEE) ON OBSERVATORIES 1 47 



I think that it is of first importance to have a permanent obser- 

 vatory furnished with a large reflecting telescope and a complete 

 equipment of auxiliary instruments for astrophysical research on 

 some site with the most favorable conditions of atmosphere. If this 

 were near the equator, it would command the richest regions of both 

 hemispheres. I mention this point in case it might not be found 

 possible to build a separate southern observatory. 



The observatory next in importance, it seems to me, would be one 

 on the top of Mount Whitnej 7- , devoted especially to solar work, or 

 chiefly so. I think the photographic method of getting the corona 

 should be tried. Theoretically it is certain of success, if only the 

 atmospheric conditions are but a little better than normal surface 

 ones. 



I suppose work could only be carried on during the summer, but 

 if the conditions are as good as the altitude would suggest, there is 

 certainly work enough for many years to come. 



The observatory at the base might be regarded as temporary, and 

 perhaps might be given up when a sufficient number of observations 

 simultaneous with similar observations at the observatory on the top 

 had been made. 



\From Professor Arthur Schuster, Director of the Physical Laboratory , 

 Owens College, Manchester, England^ 



February 18, 1903, 

 In answer to your letter of the 28th January : I should, of course, 

 be highly pleased if funds were to become available for the important 

 work sketched out by you. Taking the different points of your let- 

 ter in order : 



1. I have recently looked carefully over a good deal of literature 

 concerning solar radiation, and I confess I have not been impressed 

 by the probability that simultaneous observations at high and low 

 altitudes will help us very much. The differences which such 

 observations could show would all be due to the layer of air included 

 between the two levels. On different days the atmospheric condi- 

 tions of that layer may be very different, and yet the atmospheric 

 conditions at greater heights than, say 15,000 or 20,000 feet, might 

 be the same. You would at once have errors introduced, and the 

 observations at the high altitudes might by themselves give you 

 better results than the combination. You must face the fact that it 

 is impossible altogether to eliminate changes in atmospheric condi- 



