404 . KRETZ. 



observations taken before and after measuring the stars. The 

 circle readings as recorded show the degrees and minutes of the 

 right hand microscope, while the seconds are the mean of all 

 the readings for the morning. The terms in the fifth column 

 require a little explanation : It has been stated that the normal 

 position for the plate is trail riglit. Measures taken in this 

 position are designated as x direct. Counter-clockwise rota- 

 tion of the holder, which is the direction of increasing numbers 

 on the circle, brings the trails up. Measures in this position are 

 denoted as y dii^ect. The meaning of the other terms follows 

 at once. It should be mentioned, that for trail right, right 

 ascension, and for trail up, north polar distance, increase to- 

 wards the left on the plate, and that the numbers on the scale 

 increase towards the right. 



Table III gives the uncorrected measured coordinates in 

 terms of the scale-divisions and of y^ in, obtained as previously 

 explained. As has been stated, the micrometer could be read 

 by estimation to twothousandths of a millimeter. The mean 

 being taken to one decimal further, unity in the last place of 

 ^ m will be a tenth of a micron. This corresponds approxi- 

 mately to 0^.005. The same statement applies to the quantities 

 given in the fifth and ninth columns of the tables. In general 

 it will be found that two lines are given for the ,r's and one for 

 the ys, agreeing with what has previously been said on this 

 subject. In a few cases a negative sign is attached to y^ m: 

 this means that the next higher "line on the scale was used. 

 The numbers of the stars in the tables were assigned by me, and 

 increase with the right ascension. 



(64) 



