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SCIENCE 



[N. S. Vol. XLI. No. 1057 



more essential to progress in. astronomy than 

 in any other science. 



The earliest example of cooperation on a 

 large scale in astronomical research was the 

 proposition brought forward by Argelander 

 and his associates, half a century ago, for the 

 formation of a great catalogue of all the stars 

 to the 9th magnitude in the northern sky. At 

 the meeting of the Astronomische Gesellschaft 

 in 1869, when, after four years of preliminary 

 discussion, the project was formally initiated, 

 the plan of work adopted was the one presented 

 by Dr. Arthur Auwers, a young astronomer, 

 who, three years earlier, had been elected to 

 membership in the Berlin Academy of Sci- 

 ences to fill the place left vacant by the death 

 of Encke. In view of Auwer's youth — ^he was 

 then only 31 — ^this was a notable recognition 

 of his ability. But even more significant was 

 the fact that to him was also entrusted the all- 

 important duty of preparing the system of 

 fundamental star places which provided the 

 foundation for the entire work. 



It is impossible, without running unduly 

 into technicalities, to give an adequate idea of 

 the difficulties attending the construction of 

 such a fundamental system of star places. It 

 must suffice to say that it requires the highest 

 order of ability, a profound grasp of the prin- 

 ciples of gravitational astronomy, a compre- 

 hensive knowledge of star catalogues, rare 

 judgment, and a mastery of detail that is 

 given to but few minds. How well qualified 

 Auwers was for the responsibility placed upon 

 him is evident from the fact that the funda- 

 mental system he elaborated more than 40 

 years ago is adopted, in all its essentials, as 

 the foundation of the greater part of the most 

 refined meridian circle work of the present day. 



His connection with the " Astronomische 

 Gesellschaft Catalogue " did not end with the 

 service I have described. In addition, he 

 undertook the observation of one of the sec- 

 tions or " Zones " of the catalogue — producing 

 a model work — and was soon made chairman of 

 the commission in charge of the entire project 

 — a position he held to the date of his death, 

 January 24, 1915. Its success, therefore, is in 

 large measure due to his careful planning and 

 wise guidance. Long before his death he had 



the satisfaction of seeing the original catalague 

 completed by contributions from no less than. 

 twelve great observatories in Europe and Amer- 

 ica, and of having the plan extended, again 

 under his direction, well into the Southern 

 Hemisphere. 



G. F. J. Arthur Auwers was born in Got- 

 tingen in 1838 and received his early educa- 

 tion in the schools of his native city. His in- 

 terest in astronomy was manifested when he 

 was still a mere boy, and even before he re- 

 ceived his doctor's degree at Konigsberg in 

 1862, he had made many important contribu- 

 tions to it both by observations and by theo- 

 retical investigations. His dissertation for the 

 doctorate, on the variable proper motion of 

 Procyon, placed him at once in the front rank 

 of astronomers. In this research he struck the 

 keynote of his future life-work, " the treatment 

 of all questions concerning the positions and 

 motions of the stars." 



I shall not attempt even to enumerate his 

 many contributions to this department of 

 astronomy. His services to the A. G. Catalogue 

 have already been mentioned. It must suffice 

 to describe briefly one other research, in many 

 respects his most important — ^the new reduc- 

 tion of the Bradley stars. 



The fundamental data upon which all studies 

 of the mechanics of the stellar universe depend 

 are the positions of the stars on the celestial 

 sphere, their apparent motions on this sphere 

 (technically, their "proper motions"), their 

 radial velocities and their distances. The first 

 two of these elements are derived from the 

 star catalogues based on meridian observations. 

 One of the most important of all star cata- 

 logues is that based upon the observations of 

 Bradley, at Greenwich, about the middle of the 

 eighteenth century, for these observations were 

 the first that are at all comparable in system 

 and in accuracy with those of modern times, 

 and they were also superior to those of his 

 successors for fully half a century. As the 

 time element is of the first consequence in the 

 derivation of stellar proper motions, Bessel, 

 who in 1819 made the first reduction of the 

 Bradley observations, was fully justified in 

 giving his work the title " Fundamenta 

 Astronomise." Excellent as Bessel's work was. 



