100 



BULLETIN OF THE UNIVERSITY OF WISCONSIN 



WASHBURN OBSERVATORY, MAY 19, 1894. 

 COMPARISON OF CLOCK STARS WITH A URS^ MINORIS. 



Observer. G. C. C. 



Notes. — The instrument was so set that the readings of 

 the azimuth circle are very nearly the true azimutlis of the 

 line of sight. When the vertical circle is "Left " the zero 

 of the level scale is adjacent to the objective. The symbol 

 Ta' denotes the mean of the observed times on five threads, 

 and requires a correction to reduce it to T,. T^ was ob- 

 served on the middle thread only. The thread intervals 

 are assumed to be 



O Q 



I — - 31.5 II = - 20.5 III = 0.0 IV 



s. s. 



+ 20.3 F = + 30.8 



the signs corresponding to an observation Circle R, Star W. 

 It should be noted that owing to the reversal of the instru- 

 ment the effect of any small error in the adopted thread 

 intervals will be eliminated. 



The coordinates of a Ursce Minoris and the other constants 

 requisite for the reduction, are : 



a^ = 19 29 25.6 

 Tt = 1 1 49.88 

 ^ = 43 5 {assumed) 



log sin tt = 8.25491 

 log ^ ^"^\| ^ = 1.5232 



sin r 



log'2cosec2 cp = 0.3020 

 s. 

 Hourly rate of chronometer = —0.04 



