NA V1GA TION. 



Four modes are used, separately or jointly, for 

 finding the place of a ship at sea. 



I. PILOTAGE. Navigation in the neighbourhood 

 of land. The means of finding the ship's place in 

 pilotage are chiefly by sight of terrestrial objects, 

 as headlands, lighthouses, landmarks, or hills, and 

 other objects of known appearance, and by feeling 

 the bottom by " hand-lead soundings." 



II. ASTRONOMICAL NAVIGATION. Sights of 

 celestial objects sun, moon, planets, stars. 



III. "DEAD RECKONING" or "ACCOUNT." 

 Distance and direction travelled from a previously 

 known position. 



IV. DEEP-SEA SOUNDINGS. Depth of water and 

 character of bottom. 



3. The instruments and other aids used are : 

 For tJie first mode. The sextant, the azimuth 

 compass, station pointer, and other mathematical 

 drawing instruments, charts, books of sailing 

 directions. 



For the second. The sextant, the chronometer, 

 the Nautical Almanac, a book of mathematical 

 tables, and mathematical drawing instruments. 



B 2 



