140 



HYDROGRAPHICAL SURVEYING 



[chap. v. 



A and B respectively, and we have the mercatorial bearing 

 of AB. 



From the mercatorial bearing of A B and the diff. lat. 

 calculate the distance A B. Having the length of A B in 

 units and also in miles, we can turn the lengths of the other 

 sides from units into miles, and proceed to plot the points on 

 the side A B on the required scale, either by distances or by 

 chords. 



Example VII. — Fig. 30 illustrates the case of a long stretch 

 of coast-line of convex form, on which two stations, A and B, 

 separated by a distance of many miles, have been fixed in the 



Fig. 30, 



main triangulation. The curve taken by the coast, and the 

 obstruction to view by wooded summits, prevent stations along 

 the coast being seen from either A or B, except for a com- 

 paratively short distance. C is an inaccessible and very 



