CHAP. IV.] CALCULATING THE TRIANGULATION 103 



We will take as an example the following : 



Lat. A, 49° 30' 24" N. 

 True bearing observed B from A. N. 69° 05' 00" W. 



Angles Observed and as Corrected. 



We have in the annexed figure (17) a portion of a triangula- Example 

 tion, where all the angles have been observed at each station. °aw Tri- 

 The latitude of A is known, A B is the original long side anguia- 

 obtained by extending the base, and the true bearing of B *'°'^- 

 and A has been taken from one another, from which we 

 have deduced a mean bearing of B from A with which we 

 intend to work. The length of each side has been calculated 

 by ordinary trigonometry. We now want to calculate the 

 bearings of the different sides, so as to be able to break up 

 the triangulation into different sheets. We shall want also 



