ASTRONOMY. 



309 



Schroeterh observations. — The TJDiversity of Leyden having acquired 

 in 1876 the manuscripts and copper plates of Scliroeter's great unpub- 

 lished work on 3fars, "Areographische Beitrage zur genauern Kennt- 

 niss und Beurtheilung des Planeten Mars,^' Professor Bakhuyseu is 

 about to bring it out. Schroeter had all but completed it at the time 

 of his death, and had, indeed, it would appear, thoroughly revised the 

 greater portion of it. Professor Bakhuysen states that having reduced 

 Schroeter's observations for the position of the axis of Mars, he finds its. 

 longitude 352° 59' and the latitude 60° 32'. 



Asteroids. 



1882: 



-The following is a list of the Asteroids discovered iui 



The mass of Jupiter. — Dr. Schur has made a new determination of the> 

 mass of Jupiter from heliometer measures of the satellites, an equal 

 number of observations being made on each satellite. His results 

 are: 



From satellite I, m = 1-4- (1050.918 ± 1.667.) 

 From satellite II, m = I4- (1046.026 i 1.425.) 

 From satellite III, m = 1-=- (1047.665 i 0.046.) 

 From satellite IV, m = 1- (1046.818 ± 0.484.) 

 so that having regard to the weights, the mass of Jupiter is 1-^(1047.232 

 =L 0.365), the sun being taken as unity. Bessel's published result by the 

 same method was 1-^(1047.879), but Dr. Schur has reduced Bessel's 

 work anew, having regard to the corrections proposed by Auwers to the 

 constants of the heliometer (periodic error of screw, temperature coeflQ- 

 cient, etc.), and finds, in the mean for Bessel, 1048.629 i 0.198, and com- 

 bining by weights, the final mass of Jupiter from observations of the 

 satellites by Bessel and Schur is, 1-^(1048.311 ± 0.174). 



Dr. Schur brings up some interesting questions in regard to the per- 

 sonal errors of observations of the satellites, for an account of which 

 reference must be made to the original paper. 



Various other series of measures of the satellites are discussed, but 

 no changes are made in the concluded mass of Jupiter. 



The mean motions and the periods of the satellites require only ex- 

 tremely small changes. 



