INDEX 



565 



Equal altitudes at inferior transit 



296, 310 

 ,, ,, elimination of er- 

 rors by . . 295 

 ,, ,, meaning . . 305 

 ,, ,, short — at sea . . 372 

 ,, ,, of the stars . . 316 

 ,, ,, equation of 



296, 307, 310 



,, ,, example .. 311 



Equal altitudes, principle of . . 296 

 ,, ,, tables for valuing 



sets of . . 315 

 Equation of equal alti- 

 tudes . . . . 296, 307, 310 



Error, centring , . . . . . 7, 282 



,, collimation of theodolite 257-8 



,, index of sextant .. .. 304 



,, level, of theodolite .. 258 



,, of chronometer, by stars. . 297 

 „ ,, observations 



for . . 292 

 ,, by equal altitude of two 



stars . . . . . . 31 



,, personal . . . . . . 307 



Errors of observation, eliminating 271 



Establishment, tidal . . . . 228 



,, determination of 234 



Eyepieces, dark . . . . . . 302 



F 



Fair sheet, drawing of . . . . 381 



False station . . . . . . 87 



,, ,, rule of thumb . . 90 

 Feet, number in degree and 

 minutes . . . . . . App. L. 



Field boards . . . . 45, 255, 374 



Fittings for boats 50 



Fix, by tracing-paper . . . . 128 

 Fixing, by calculation from angles 



at jjosition . . . . 170 

 ,, by station pointer with 

 points beyond limit of 



pointers . . . . 465 

 ,, care in choosing object 



for 24 



,, general rule for observmg 



angles . . . . . . 28 



,, marks . . . . . . 165 



,, marks from ship. . . . 167 



,, position from two objects, 

 distance between them 



being known . . . . 467 



,, size of angles admissible 28 

 ,, small error in intersecting 



angle 29 



,, soundings . . 194, 198 



Flag-staff 49 



Floating beacons, approaching to 



pick up . . . . . . . . 58 



Floating moored beacons: 



In shallow water . . . . 507 



Triangulation scheme . . 476 



Triangulations by means of 472 

 Use of, with ship triangula- 

 tions during irregular or 

 detailed surveys . . . . 506 



Moorings and flags . . . . 473 



Rigging, handling and general 

 management of . . . . 499 



Protection of, and distin- 

 guishing by night . . . . 502 



Floating triangulations : 



Adjustment of . . . . 495 



Angles required at its beacon 487 

 Astronomical observations . . 497 

 Checking position of beacons 

 and the scale . . . . 497 



Connecting the ship with a 

 beacon near by for the pur- 

 pose of triangulation . . 492 

 Connection of, with shore 

 object and disposition of 

 ships engaged . . . . 4ul 



Observations at night . . 4:i'6 



Obtaining angles at the bea- 

 cons . . . . . . 4:5 



Obtaining the scale . . . . 4o0 



Preimration of angles for 



calculating and plotting . . 489 

 Rapid plotting . . . . 489 



Signalling angles between 

 ships engaged . . . . 488 



.Signalling the plot . . . . 490 



Foreign measures of depth App. V. 



Form for comparison book App. H. 



,, deck-book . . App. G. 



height book . . . . 262 



G 



Galton Sun signal . . . . 37 



Gauge, automatic tide . . . . 223 



Gnomonic projection . . . . 98 



,, ,, graduations 



on . . 383 

 ,, „, graduations 

 on Ath- 

 erton' s 



method 462 



Graduation of chart . . . . 383 



,, of plans . . . . 387 



,, on central meridian . . 388 

 , , taking off latitude and 



longitude . . . , 389 

 ,, before plotting 164, 174 



H 



