74 BULLETIN OP THE UNIVERSITY OF WISCONSIN 



_ A tan r sin 15' _ [1.7959] 



c* — 



2 {b' - h") sin 1" 26' - 26 

 from which we obtain the following three values: 



It p tf 



d = 4.72 = 4.74 = 4.73 

 the mean of which may be adopted. 



