xxxii GENERAL SUMMARY OF SCIENTIFIC AND 



double stars : a work which he did not live to complete, but 

 bequeathed in its incomplete state to the Royal Astronom- 

 ical Society, by whose authority it has been published as a 

 catalogue of 10,300 multiple and double stars. A most im- 

 portant portion of this work was left uncompleted by its au- 

 thor, and has not been published by his editors. We refer 

 to the descriptions of the distances, magnitudes, and colors 

 of the stars. This important defect in the work, as it now 

 stands, will, we have reason to hope, soon be supplied by the 

 publication by the Naval Observatory at Washington of a 

 far more important catalogue of double stars that has been 

 in process of compilation during some years past by Mr. 

 Burnham, of Chicago. This gentleman, by far the most in- 

 dustrious amateur astronomer in this country, has continued 

 to make numerous contributions to this branch of astronomy, 

 his labors beins: confined to the detection of new and ex- 

 tremely difficult companions to well-known stars. 



The Hamburg Observatory has issued its first official pub- 

 lication in the shape of a memoir by Helmert on the stars of 

 the cluster in Sobieski's Shield, the same cluster which was 

 studied by Lamont in 1836. But slight movements of the 

 individual stars can be deduced from a comparison of Hel- 

 mert's and Lamont's observations, although they were sepa- 

 rated by an interval of forty years. 



Nebulae. The nebulae have been studied of late from several 

 points of view. Drawings of the more famous ones have 

 been made in the United States at Washington by Holden, 

 and at Cambridge and Washington by Trouvelot. In the 

 southern hemisphere we note several contributions by Ellery 

 at Melbourne. 



The question of secular changes in the appearances of neb- 

 ula? can, it would seem, be best decided by making careful 

 drawings of them at the present time as seen through tele- 

 scopes of very feeble power, such as were necessarily used by 

 the early astronomers. In this way Temple has traced the 

 outline of the nebula near Merope, describing it as elliptical; 

 while Wolf, at Paris, using a somewhat larger telescope, per- 

 ceived two nuclei distant seven seconds from each other. 

 Stephan having been unable to discern the nebula with his 

 large telescope during the winter of 1874-5, it has been con- 

 cluded that this nebula is certainly variable. 



