ASTRONOMY. 165 



constants of reduction are known to a good degree of approximation, 

 and it oiigtit not to be difQcult for astronomers to unite on a common 

 system of values of these constants and also on a uniform notation to be 

 used in reductions. The great advancement in stellar astronomy made 

 by Bessel in Lis " Tabulae Itegiomontanaj " seems to have been partly 

 disregarded and lost, and his methods for bringing the labors of many 

 observers into harmony, and of making them all tend towards the ad- 

 vancement of the science, have sometimes been overlooked and for- 

 gotten. 



Again, if a large list of clock-stars is at hand, the astronomer is apt 

 to make his work purely differential. In many cases this may be his 

 best course, but such work would be more easily reduced and compared 

 if it could all be referred to a common system of clock-stars. The com- 

 putation of systematic errors would not be avoided ^ but the work would 

 be made easier and more certain. 



In order to obtain an extensive and convenient ephemeris of the clock- 

 stars, suitable for general use, it would be better to make such a work a 

 special publication. In this way the adoption of the mean positions of the 

 stars and the selection of the constants of reduction and the system of 

 notation could be brought under the direction of one ofiBce. The work 

 should be so elaborate that the apparent position of a star could be in- 

 terpolated with ease and certainty for any time, but even with such an 

 extension the cost of publication would not be great. I hope that the 

 Astronomische Gesellschaft may be willing to undertake a work of this 

 kind. (A. Hall, Washington, 1884, May 30.) 



Positions of polar stars. — Vols, i and ii of the Annals of the Observ- 

 atory of Kieu- are largely devoted to the observations made of a con 

 siderable number of circumijolar stars with the object of forming a 

 standard set of places. These two interesting volumes cannot be epito- 

 mized here, but reference may be made to a very complete review of 

 them in the BuUetin Astronomiquc, Vol. i, p. lo9, by M. Callandreau. 



SchoenfelcCs Durchmusteruny,from—2^ fo— 23°. — At the Vienna meet- 

 ing of the German Astronomical Society, Dr. Schoenfeld gave an ac- 

 count of the progress of his work since the Strassburg meeting. 



G99.3 hours of E. A. with 363,351 star-positions have been observed. 

 The principal catalogue now contains 113,700 stars between —2° aiul 

 —23° and 1,101 stars near these limits. In il'\ i. c, from 9'' 0'" to 0'> 

 0'", the work is completed. (This work is now done; 1S85.) 



It is expected to begin the printing of the principal catalogue in May 

 or June, 1884. Probably some 40,000 stars brighter than 9.1 mag. exist 

 in the region. 



Greemvich catalogue of stars. — The volume of Oreenwieh Observations 

 for 1882 has been published. It was mentioned in the Astronomer 

 Royal's report to the board of visitors that this had been passed for 

 press early in May. It is the first volume relating to a year of which 

 the work was wholly under the direction of Mr. Christie, as Sir George 



