58 REPORTS ON INVESTIGATIONS AND PROJECTS. 



the Solar Observatory No. 2, but the developments of the last few 

 months have cleared up some points of uncertainty, especially as 

 regards the desirability of including a systematic study of the solar 

 radiation in our observational program. Furthermore, the ques- 

 tion recently raised by the editor of the Popular Science Monthly, 

 as to the wisdom of establishing the Solar Observatory in a State 

 already so well represented bj' the Lick Observatory, indicates that 

 the purpose of the Solar Observatory is not yet clearly apprehended 

 by some men of science. The Carnegie Institution would certainly 

 run counter to its well-defined principles by duplicating the work of 

 the Lick Observatory, and the Solar Observatory would not accom- 

 plish its purpose if this were done. 



The purpose of the Solar Observatory may be defined as follows : 



( 1 ) The investigation of the sun (a) as a typical star, in connection 

 with the study of stellar evolution ; (b) as the central body of the 

 solar system, with special reference to possible changes in the inten- 

 sity of its heat radiation, such as might influence the conditions of 

 life upon the earth. 



(2) The choice of an effective mode of attack, involving (a) the 

 application of new methods in solar research ; {b^ the investigation of 

 stellar and nebular phenomena, especially such as are not within the 

 reach of existing instruments ; and ic) the interpretation of these 

 celestial phenomena by means of laboratory experiments. 



(3) The design and construction of a large reflecting telescope 

 and of new types of instruments peculiarly adapted for the purposes 

 in view, with special reference to the possibilities of research through 

 the study of celestial objects under laboratory conditions.* 



4) The accomplishment of the foregoing purposes at a site where 

 the atmospheric conditions have been shown to be exceptionally 

 favorable : Mount Wilson (5,886 feet), in southern California (lat. 

 + 34° 13' 26", long. W. 118° 3' 40"). 



(5 The furtherance of international cooperation in astrophysical 

 research through the invitation to Mount Wilson, from time to time, 

 of investigators specially qualified to take advantage of the oppor- 

 tunities afforded by the Solar Observatory. 



STAFF. 



My principal associates on Mount Wilson are Ferdinand Ellerman 

 and Walter S. Adams, assistant astronomers. Mr. Charles S. Backus 

 is a general assistant. At the Pasadena ofi5ce and instrument shop 



* See The Development of a New Observatory, Publications of the Astronom- 

 ical Society of the Pacific, Vol. XVII, p. 41. 1905. 



