512 



HYDROGRAPHICAL SURVEYING [chap, xxi 



AREA 



B E 



Clear 



Fig. Ill- — Illustrating a Beacon Triangulation connected by Station-Pointer 

 Fixes and True Bearings to triangulated Shore Objects at Night by 

 Two Ships simultaneously intervisible at Beacons i and 13 by means of 

 Searchlights. The Co-ordinates of the Shore Objects are known. 



