( 99 ) 



were observed alternately, and of each of (liese pairs the one in the 

 position circle to the right, the other in the position circle to the left. 



The readings were always made with each of the two micros- 

 copes both on the preceding and on the following division. 

 The corrections for run and for the level reading were applied 

 exactly as before (comp. Coiitrlb. I. p. 280), the refraction was 

 derived from the tables of Bessel and the declinations of the 

 stars were taken as before from the Nautical Almanac, i. e. 

 from the catalogue of Newcomb. Only now and then I have 

 also observed stars from the Berliner Jahrbuch, namely v Piscinm, 

 ó Cassiopeiae and <p Persei. To reduce them to Newcomb I have 

 applied to them the following corrections: - 0".l, — 0".8 and 

 + 0".7, according to data communicated to me by Dr. E. F. v. d. 

 Sande Bakhuyzen. 



The reading for the zenith was assumed to be constant for each 

 night and determined so as to make all the stars agree inter se as 

 well as possible. By the regular alternation of the positions of the 

 instrument an error in the adopted zenith point was eliminated almost 

 entirely. 



The observations were made in 6 positions of the circle, each 

 differing from the next by 30°. 



As an example I will first give the observations of one night 

 in full. 



I now proceed to give for all the observations the resulting values 

 for the latitude in 4 columns : for the north stars circle right and left 

 and for the south stars circle right and left. To these 1 add the 

 approximate zenith distances of the stars. 



The observations at zenith point 210'' are distributed over two 

 nights, Dec. 2 and Dec. 6. Because it is not permissible to consider 

 the zenith point for the two as exactly equal, it seemed better 

 to exclude from the observations of Dec. 2 the only southern star 

 obtained. For the rest no observations are excluded, not even the 

 few which deviated rather much. 



For each position of the circle I have combined the results for 

 the two positions of the instrument, but I kept apart those from the 

 northern and from the southern stars and so I obtained : (see p. 100) 



To the results from the northern and the southern stars I have 

 added their differences and their means. In so far as we may 

 assume that the north and the south stars had in the mean the 

 same zenith distance, the former represent the corrections to the 

 measured arcs of 2 z for errors of division -j- double the correction 

 to the measured z for flexure (comp. Contrih. I p. 285), while on the 



• 7* 



