36 A MANUAL FOR NORTHERN WOODSMEN 
been run out and the latitude and departure computed, as 
given. The result shows that the point reached is north 
FIGURED LATITUDES AND DEPARTURES 
Latitude. 
Departure. 
N. 
S. 
E. 
W. 
A — B 
9.92 
17.36 
B —C 
12.35 
8.70 
C —D 
11.59 
4.22 
D—E 
7.00 
14.67 
30.94 
9.92 
26.06 
18.89 
9.92 
18.89 
21.02 
7.17 
and east of the starting point, much further north than 
east; hence a course somewhat west of south 
E must be set to reach it. In the figure E X 
I represents the latitude reached and A X the 
/ departure. 
/ Now to find the bearing of E A we have 
/ 4 X 7 17 
/ tan. A E X =—% = = . 3411 . 
A Z_l x EX 21.02 
I A E X from the table of tangents = 18° 50'. 
j S 18° 50' W is therefore the bearing required. 
S The length of E A may also be found, since 
it is the hypothenuse of a right angled tri¬ 
angle whose base and altitude are the latitude and de¬ 
parture given. 
4 / 21.02 2 + 7.17 2 = 22.21, 
the distance required. That this value and that for the 
angle differ somewhat from the true ones is due to the 
errors of compass surveying. 
In a similar way the course and distance of an inacces¬ 
sible line may be computed or omissions supplied in notes. 
