xxiv GENERAL SUMMARY OF SCIENTIFIC AND 



NEBULA. 



Winnecke, of Strasburg, has begun work again in this field with 

 powerful instruments. Bruhns has begun the publication of charts 

 of nebulae observed in zones at Leipzig. Yogel has published the 

 results of a determination of the positions of all the nebulae in the 

 Leipzig zone of the new Durchmusterung. It takes its place at once 

 with the works of Auwers, Schonfeld, and Schultz, and Vogel's 

 former work of 1867, as an acknowledged classic. Vogel has also 

 made some drawings of hitherto unj^ublished nebulae. Forty or 

 fifty southern nebulas, formerly figured by Herschel,have been drawn 

 and studied by Ellery, of Melbourne, and his assistants, and the re- 

 sults will shortly be published. Gould, of Cordoba, has made many 

 photographs of southern clusters and double stars. A monograph 

 of the ring nebula of Lyra has been published by Holden, of Wash- 

 ington, as well as a detailed discussion of all jDublished drawings 

 and observations of the nebula G. C. 4403, in which it is endeavored 

 to show a veritable proper motion to this body. Tisserand, of Tou- 

 louse, and Tempel, of Florence, as w^ell as Holden at Washington 

 and Trouvelot at Cambridge, have published preliminary results of 

 their work on the Orion nebula. Bredichin, of Moscow, has inves- 

 tigated the spectra of many planetary nebulae, and finds them in 

 general to be of one type, and usually to be sensibly the same. 

 Dreyer, of Parsonstowu, is preparing a supplement to Herschel's 

 general catalogue. 



DOUBLE STARS. 



Double stars have been faithfully observed during the past year, 

 the most noteworthy publications of private observers being those 

 of Dembowski, Gledhill and Crossley, Wilson and Seabroke, and 

 Barclay. 



Otto Struve at Pulkova, Dembowski at Gallarate, Dungr at 

 Lund, Newcomb and Hall at Washington, Wilson and Seabroke, 

 of Rugby, Crossley and Gledhill, of Halifax, and others, have jDub- 

 lished important measures of difficult stars. Burnham, of Chicago, 

 and Howe, of Cincinnati, have published lists of new double stars. 

 A method for obtaining the relative personal equation of various 

 double -star observers by simultaneous observations of a selected 

 list of doubles is proposed by Struve, and will be followed by sev- 

 eral observers. 



The double - star observations and discoveries of O. M. Mitchel 

 have been prepared for the press by the present Director of the Cin- 

 cinnati Observatory, Professor Ormond Stone, and will shortly be 

 issued. 



The supposed discovery of a companion of Procyon in 1873, and 

 the subsequent observations of 1874 by Otto Struve, are now sup- 



