38 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



to determine the mass of that planet with very great exact- 

 ness. 6 B, LXXXL, 141. 



THE LUNAR THEORY. 



The theory of the movements of the moon, which has oc- 

 cupied so many astronomers since the days of Laplace, or, 

 more correctly speaking, since the days of the earliest Chal- 

 dean observers, has most recently received some additions 

 by the labors of Schjellerup, who has paid especial attention 

 to the acceleration of the moon's mean motion, and the iden- 

 tification of the eclipses that are recorded by the ancient as- 

 tronomers. Schjellerup has especially sought for confirma- 

 tion of his investigations by computing the eclipses recorded 

 in the Chinese classics, as published by Dr. Leggie. Among 

 the eclipses subjected by him to computation are those which 

 occurred 708 years B.C., 600 years B.C., and 548 years B.C. 

 Oversigt Kongelige Danske md. Selsk.^ 1874, 61. 



ASTRONOMICAL OBSERVATIONS AT MANNHEIM. 



In the volume ot astronomical observations at Mannheim, 

 recently published by Schonfeld, he gives the observations 

 of nebulae and stellar clusters that have been made by him 

 since 1862, amounting in all to eight hundred and twenty 

 complete measurements of the distances between nebulae and 

 neighboring stars. His object has been to determine the 

 positions of as many nebulae as possible, as accurately as he 

 could by measuring micrometrically their distances from 

 neighboring stars. In this work, in which he was almost 

 the only observer twenty years ago, others have also become 

 active since then, and have even surpassed him in the quan- 

 tity of work done, though not in quality. 



The condition of the atmosphere has been carefully noted 

 by him at each observation. The constant differences be- 

 tween his own positions and those of other observers, such 

 as Schultz, are very small. Astro7i. J3eob. auf der Grosse^i 

 Sternwarte zu Ilannheim, Dr. E. Schonfeld, 2. Abth., 1875. 



ASTRONOMICAL OBSERVATIONS AT MILAN. 



The recent'publication No. 5, from the Royal Observatory 

 at Milan, contains various astronomical observations, among 

 which are especially prominent the photographic plates rep- 



