April 22, 1921] 



SCIENCE 



375 



and measured the positions of numerous 

 planetary nebulse which are given in the same 

 volume. His orbits for several of the more 

 interesting systems on which he had been 

 working appear at the end of that volume. It 

 will be seen that Mr. Burnham had largely 

 given up the search for new double stars 

 while at the Lick Observatory, regarding it 

 as more important that accurate observations 

 should be made of the systems already dis- 

 covered, particularly those for which large 

 instruments were necessary. 



Vol. I. of the PuMications of the TerJces 

 Ohs&rvatory , issued in 1900, is entitled " A 

 General Catalogue of 1290 Double Stars Dis- 

 covered from 1871 to 1899 by S. W. Burn- 

 ham." It gives in order of right ascension 

 the history of all of the Burniam stars up to 

 p No. 1290. Aside from his own observa- 

 tions, it summarizes the results of all other 

 observers of these stars and gives diagrams 

 and orbits, by the author and others, of 

 several interesting systems. He did not allow 

 himself to be disti-acted from his specialty 

 by the allurements of other fields of obser- 

 vation: it was seldoni that he looked at 

 nebulse unless there were double stars to be 

 measured therein; and he had no time for 

 observing comets, however interesting. He 

 made an exception in locating Halley's comet 

 on September 15, 1909, two nights after it 

 had been first caught on a photographic plate 

 by "Wolf at Heidelberg: thus Burnham's eye 

 was the first to see the comet, then an ex- 

 tremely faint speck, on this return to peri- 

 helion. 



During tbe beginning of Mr. Burnham's 

 use of the 6-inch telescope, he felt the great 

 need of a single catalogue of all double stars 

 in the iNrorthern Hemisphere and he therefore 

 arranged a manuscript catalogue of all kno^vn 

 double stars within 121° of the north pole. 

 This was conveniently indexed and proved of 

 great service to the observer. He revised it 

 in two MS. editions, the third of which 

 allowed ample room for expansion and is still 

 in use. The preparation of this catalogue had 

 entailed a great amount of labor, as it was 

 constantly kept up to date. Mr. Burnham 



says of it that " very few will fully appreciate 

 the enormous amount of hard work which has 

 been necessarily expended in the preparation 

 of such a work. ... It should be remarked in 

 this connection that with the exception of 

 the four years from 1898 to 1902 all this 

 astronomical work, with the telescope and 

 otherwise, has been done when eight or more 

 hours of at least six days in the week were 

 very much occupied with other and different 

 affairs of life." After his retirement from 

 active observations, Mr. Burnham turned this 

 MS. catalogue and the responsibility of its 

 up-keep over to Professor Eric Doolittle, 

 whose premature death in 1920 is much 

 lamented. From him, by prior arrangement, 

 this passed on to Professor Robert G. Aitken, 

 of the Lick Observatory, who thus carries on 

 the work which will eventually result in a 

 new edition of the " General Catalogue of All 

 Double Stars," now to be mentioned. Efforts 

 had been made for many years to have this 

 great work published, but it could not be 

 brought about until the Carnegie Institution 

 of Washington in 1905 undertook to publish 

 it. The composition was done with great care 

 by the University of Chicago Press, and 

 Part I. was published before the close of 1906. 

 It lists 13,665 double stars and summarizes 

 the numerical information about them, in a 

 quarto volume of 275 pages. Part II., of 

 1,086 pages, gives details of all important ob- 

 servations of the pairs, with many diagrams. 

 It constitutes a magnum opus of which any 

 scientist could be justly proud. 



With the 40-inch telescope of the Terkes 

 Observatory, Mr. Burnham gave no time to 

 the discovery of new doubles. In fact, he 

 avoided them, if possible, and occasionally 

 mentioned seeing some which he did not 

 record. In recent years he took a good deal 

 of interest in the determination of the proper 

 motions of the brighter stars by micrometric- 

 ally connecting them with neighboring faint 

 stars, for which a n^ligible proper motion 

 could be assumed. This work was largely to 

 lay the foundation for a greatly increased 

 knowledge of proper motion in the future. Mr. 

 Burnham realized very fully the great advan- 



