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SCIENCE 



[N. S. Vol. XXXIX. No. 998 



THE SOLAE OBSERVATORY 



From the date of its establishment nine 

 years ago this observatory has been one of 

 the most important of the enterprises fos- 

 tered by the institution. It has called for 

 heavy annual appropriations; it has grown 

 with extraordinary rapidity and with 

 equally extraordinary productivity; and it 

 is now an organization whose staff of in- 

 vestigators, research associates and collabo- 

 rators, constructors, computers, designers, 

 mechanicians and operators includes up- 

 wards of sixty individuals. By reason of 

 the widespread popular and technical at- 

 tention given to astronomical science, and 

 by reason of the novel equipment of this 

 observatory and the relatively new field en- 

 tered by it, the world looks with special in- 

 terest on its development, quite apart from 

 the keen general interest in the contribu- 

 tions it has made and may be expected to 

 make to astrophysics. This special interest 

 centers in the fact that the experience of 

 the observatory furnishes the details of an 

 experiment on a large scale in a difficult 

 field of inquiry, for which ways and means 

 of corresponding magnitudes have been 

 available. In general the means at hand 

 for such enterprises have been incommen- 

 igurate with the obstacles to be overcome, 

 and progress has been hindered, delayed or 

 blocked until necessity has devised some in- 

 direct way of surmounting these obstacles. 

 But, on the other hand, this necessity has 

 hitherto exerted a highly beneficial influ- 

 ence in stimulating discovery and inven- 

 tion, and one may perhaps question whether 

 in the past ampler means for the pursuit of 

 systematic research would have been on the 

 whole advantageous for the advancement 

 of knowledge. Some eminent authorities, 

 indeed, still question the propriety of the 

 endowment of research in any but educa- 

 tional establishments. Contemplative minds 



are therefore awaiting the results of the 

 experiment of the solar observatory with an 

 eagerness only exceeded by that of the pop- 

 ular mind for information concerning the 

 latest discoveries and advances in astro- 

 nomical science. 



In the meantime, with the installation of 

 additional equipment and the application 

 of appropriate methods of research, the ob- 

 servatory is increasingly productive. The 

 principal results of the work of the past 

 year are summarized by the director in his 

 current report under seventy-two heads. 

 No further summary of these results may 

 be attempted here; attention may be given 

 to a few only of the salient items of inter- 

 est suggested by the report as a whole. The 

 year has been one of minimum solar activ- 

 ity and noteworthy for a nearly complete 

 absence of sun-spots. This has proved ad- 

 vantageous for the pursuit of studies of the 

 sun's magnetism now definitely proved by 

 work done at the observatory during the 

 year. This advance in solar physics is of 

 the highest interest by reason of its prob- 

 able relations to terrestrial magnetism and 

 to cosmic physics. Stellar and laboratory 

 work have gone forward at a highly pro- 

 ductive rate, and the subjects of solar, 

 stellar and laboratory spectra and stellar 

 velocities are among those instructively con- 

 sidered in the director's report. Evidence 

 has been accumulated tending to show that 

 light is absorbed in space, and that such a 

 phenomenon will not only elucidate others 

 hitherto obscure, but furnish means of 

 measuring the greater depths of the visible 

 universe. Professor Kapteyn has continued 

 to act as research associate and adviser in 

 the program of researches undertaken. 

 The important results attained by Pro- 

 fessor Stormer, who spent some time at the 

 observatory as a research associate in 1912, 

 in his investigation of solar vortices, and 



