ADVISORY COMMITTEE ON ASTRONOMY 95 



tion. For example, the latter requirement applies with particular 

 force to researches upon solar radiation. 



So far as we know, no single point on the earth's surface unites 

 all the advantages required in the various classes of astronomical 

 observation. It is very probable that a carefully planned search 

 would result in the discovery of sites which would fulfil the re- 

 quirements of certain special researches more perfectly than any 

 now known, but in any comprehensive plan of research several 

 stations might have to be selected, each adapted to the particular 

 purpose required 



In studying these matters from time to time it has appeared to us 

 with increasing force that the similarity of ideas which naturall}- 

 suggest themselves in the consideration of each topic points to the 

 advisability of treating them together under a single organization. 



The object of this organization would be to provide, under the 

 direction of the Trustees of the Carnegie Institution, for the accom- 

 plishment of a variety of large and important researches which re- 

 quire special conditions of atmosphere, latitude, or instrumental 

 equipment not now available, by investigators whose previous work 

 shows them to be the best qualified. More specifically, this organi- 

 zation could accomplish three results of the first importance : 



(i) Observation by precise modern methods upon objects in the 

 far southern sky which have been wholly neglected hitherto, or in- 

 sufficiently observed, in order to complete the evidence necessary 

 for generalizations in certain lines of astronomical research. 



(2) The utilization of exceptional atmospheric conditions which 

 exist at certain points on the earth's surface, and particularly at 

 great altitudes, for the prosecution of important investigations which 

 can not be undertaken to advantage in the absence of such conditions. 



(3) The employment in such researches of the ablest astronomers 

 of all nationalities through the provision of necessary equipment 

 and other facilities required for the special work which they may be 

 prepared to undertake. 



Observations in the Southern Hemisphere. 



In our general report we have pointed out the need which exists 

 of providing for special obser\^ations in the southern hemisphere 

 upon objects which can not be reached by observatories in northern 

 latitudes, with a view to the completion of the evidence which is 

 absolutely necessary for the proper and effective discussion of cer- 



