ASTRONOMY. 113 



tween two stars observed at both places does not exceed one-terth of 

 a magnitude." 



The principal work of the meridian photometer, the revision of the 

 Durchmiisterung magnitudes, is now approaching completion, nine- 

 teuths of the observations having already been made. During 1887 the 

 observing list will be extended to include stars in the first 20^ of south 

 declination. 



Observations of the eclipses of Jupiter's satellites, comparison stars 

 for variables, etc., are made with the photometer attached to the 15- 

 inch equatorial. 



A comparison of photometric methods. — Mr. S. C. Chandler, jr., pre- 

 sented at the Buffalo meeting of the American Association an important 

 paper on "A comparative estimate of methods and results in stellar 

 photometry," in which he reaches the conclusion (also reached by Dr. 

 G. Miiller, of Potsdam,— Vrtljscbr. d. astron. Gesellsch., 20 : 2G1-267), 

 that the photometers now in use give no advantage, in point of accu- 

 racy, over direct eye estimates of differences in magnitude made accord- 

 ing to Argelander's well known method. With regard to accidental 

 errors, Mr. Chandler concludes that " eye-estimates" are nearly three 

 times as accurate as photometric measures, and he also points out that 

 several variables have been detected and their periods and light-curves 

 well determined by careful eye-estimates, whose whole range of bright- 

 ness is no greater than the range of error in photometric observations. 

 Eeference should be made to Mr. Chandler's paper in the Astronomische 

 Nacbrichten, vol. 115, p. 145, merely an abstract of his communication 

 having been published in the Proceedings of the American Associa- 

 tion. 



A proposed new catalogue of magnitudes of southern stars. — Mr. E, F. 

 Sawyer, of Cambridge, has been at work since 1882 upon a determina- 

 tion of the relative magnitude of the stars included between the equa- 

 tor and 30° of south declination, and not fainter than the seventh mag- 

 nitude. The observations are made with an opera= glass (magnifying 

 two and a half times) put slightly out of focus. The number of stars 

 comprised will approximate 3,ri00, and the average number of observa- 

 tions for each star will be about three and one-half. Mr. Sawyer Innds 

 from r>93 stars, each observed twice, that the average difference between 

 two independent determinations of a magnitude of a star is 0.112 of a 

 magnitude, which corresponds to a probable error of a single observa- 

 tion of ±0.0(?5. It is expected that the work will be completed and 

 ready for publication within a year. 



STELLAR SPECTRA. 



Photographic study of stellar spectra at Harvard College Observatory. — 

 Professor Pickering has announced in his annual report an extensive 

 investigation in stellar spectra, by means of photography, undertaken 

 H. Mis. 600 8 



