ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



stars at least four nights' observations were made. The re- 

 ductions are complete, and the observations are reduced to 



1870.0. 



The fainter stars (10-12 mag-.) were observed by Aa and 

 A(~ with other stars at least on two nights for each star. 



B t deals with the accuracy of the observations, and first, 

 for the brighter stare, the probable error of a single observa- 

 tion in 8 is found to be 0.228", in p (reduced) 0.306". 

 The probable errors for the mean of each night are more im- 

 portant, and result as follows (no dependence of the probable 

 errors on the distance or the position-angles being evident) : 

 probable error of one night in s, 0.190", in p (reduced) 

 0.165". For the final position (at least four nights) these 

 become, in s, 0.092"; in p, 0.080". For the Ao and Ao of the 

 brighter stars these are 0.097" in R. A., .089" in KT. P. D. 

 The positions for the fainter stars are determined within less 

 than 1" in each co-ordinate, which Dr. Yogel considers suffi- 

 cient for his purpose. 



5 treats of the determinations of the brightness of the 

 stars of this cluster. The 1*76 stars of the cluster range be- 

 tween the 6.5 and 13 magnitudes. 



Each one of the fainter stars (higher than 10 mag.) was 

 determined by eye estimates of magnitude at least five times ; 

 the probable error of the mean is 0.14 magnitude. The 

 brighter stars were determined on several evenings by the 

 eye, and on two nights each was compared by a Zollner 

 photometer with one of the standard stars. A table (p. 12) 

 gives the magnitudes of the brighter stars, 1st, by eye (Yo- 

 gel); 2d, by eye (Argelander) ; 3d, photometric magnitude^ 

 assuming the lio-ht ratio -.-ttt, or 0.397. The agreement is 

 remarkable, but the table shows (what was already known) 

 that Argelander's magnitudes higher than 9.0 m make the 

 stars too bright. 



6 gives the observations of the stars (in tabular form), 

 and the results. A difference between the spring and au- 

 tumn observations, in both A and A3, of one of the stars in- 

 dicates possibly a parallax of about 0.3". 



g : gives the observations of the fundamental stars, and 

 catalogue of the 30 brightest shim. The observations are of 

 relative A and \l of the four fundamental stars, and of two 

 of Argelander's stars in h Persei, and also meridian observa- 



