BULLETIN OF THE UNIVERSITY OF WISCONSIN 

 Science Series, Vol 1, No. 3, pp. 57-107, June, 1895 



STUDIES IN SPHERICAL AND PRACTICAL 



ASTRONOMY. 



BY GEORGE C. COMSTOCK, 

 Director of the Washburn Observatory. 



The following pages contain an exposition of methods 

 for the treatment of certain problems in spherical and prac- 

 tical astronomy, which, from his own experience, the 

 author has found to be advantageous in practice. For the 

 most part these methods are original and hitherto unpub- 

 lished, but in part they are due to others, whose published 

 exposition of them is not readily accessible to American 

 students. In cases of the latter kind due acknowledgement 

 is made in connection with the presentation of the subject 

 matter, but I have not scrupled to modify or to completely 

 alter the mode of presentation of those subjects which 

 have been treated by others, adopting in each case that 

 method which has seemed to me simplest and most easily 

 followed. 



MINOR SUGGESTINOS. 



The Reduction of Level Readings:. — To determine the incli- 

 nation of a nearly horizontal line or plane by use of a spirit 

 level, Chauvenet ' gives rules which in all cases require the 

 same operations to be performed with the level, but in 

 which the mode of treatment of the level readings depends 

 upon the manner in which the scale is graduated, one 

 method when the zero is at the end of the scale and another 

 when it is in the middle of the scale. The modes of re- 

 duction are sufficiently illustrated in the following ex- 

 amples given by Chauvenet.^ 



1 Spherical and Practical Astronomy, Vol. U, §§ 52, 55. 

 * Loc. cit. 



