668 



HYDROGRAPHICAL SURVEYING 



PAGES 



Scale of chart . . 64, 201, 271, 382 

 Scales, brass . . . . 33 



Sea lark sweep . . . . . . 440 



Sections of reef slopes . . . . 207 



Sensitive circles . . . . : . 26 



Sentry, submarine . . . . 406 



,, ,, use of . . 216 



Sextant angles . . . . 83, 254 



,, ,, between objects at 



different eleva- 

 tions . . . . 83 



„ ,, from ship . . 167 



,, ,, to pick up posi- 



tion by . . 197 



,, elevations by . . 258, 266 

 ,, Hadley's , . . . 6 



,, observations at an ob- 

 servatory .. .. 313 



,, soimding . . . . 10 



,, spirit-level on index bar 



of 9 



stand .. .. 12,273 



,, triangulation by . . 83 



,, true bearing by . . . . 356 



Shallow water, use of floating 



moored beacons in . . . . 507 



Sheet, graduation of, before 



plotting 164, 174 



Ship sounding . . . . . . 209 



„ ,, alternative method 210 



„ ,, simplified method 422 



„ sweeping . . . . . . 436 



,, use of, as station . . . . *167 



Shoals, close examination of . . 202 

 ,, searching for . . . . 214 



,, out of sight of land . . 205 

 Shoal soundings, unexpectedly 

 striking . . . . . . . . 206 



Sidereal chronometer, use of . . 328 

 Sights. See Observations 



Silk threads 20 



Sketch 93 



Sketching, hints for .... 94 



Sketch survey by compass bear- 

 ings and vertical angles . . 184 

 Small angles, desirable for plot- 



tmg 126 



Small scale charts, misleading . . 201 

 Small triangles, errors in. . . . 82 



Sound, base by . . • • • • 73 



„ ,, "^ formula .. App. F. 



„ velocity of . . . . 75 



Sounding . . . . • • • • 194 



a bar 209 



,, banks . . . . . . 205 



book 198 



,, deep-sea . . . . 391 



,, management 

 " of ship . . 400 



„ „ preparing for 399 



routine casts 403 



rAGKS 



Sounding, deep-sea signals for . . 3yj 

 ,, ,, taking a . . 399 



„ ,, time occuiJied 402 



., tittings for ship . . 209 



,, importance of . . 194 



,, lines, doubling . . 202 



,, machines .. .. 392 



,, machine in whalers . . 52 

 ,, ,, wire on poop 211 



,, ,, method of 



working 

 , , off points of land or reef 

 ,, on very large scales . . 



,, on voyages 



, , out of sight of land . . 



, , rods 



,, ,, sinkers for 



,, roller . . 

 ,, sextant 

 ,, ship 



,, ,, simplified method 



,, starring off a lighthouse 



or round the ship . . 

 „ taking a deep-sea 



,, traveller, Douglas-Scha- 



fer 

 ,, weights used for 



Soundings, calling 



direction of lines of . . 

 distance between lines 



of 



in a harbour . . 



instruments for 



long lines of, off shore 



on original chart 



recording 



reducing 



shoal, unexpectedly 



striking 

 sliding scale for reduc- 

 tion of 

 suspicious 

 Spherical excess . . 

 Spheroid, correction for . . 

 Spirit level on index bar of sex- 

 tant 



Squaring in . . . . 177, 375 



Standard chronometer, daily 



mean error of . . 

 Stand, artificial horizon . . 



,, sextant . . . . 1: 



,, ,, levels on, advan- 



tages of 

 Star atlas . . 

 ,, catalogues 

 ,, example of latitude by 

 Stars, calculating apparent places 



of 289 



,, choosing pairs . . . . 274 

 ,, daybreak at sea . . . . 365 

 „ identification of . . 366 



397 

 197 

 203 

 403 

 205 

 394 

 394 

 425 

 10 

 209 

 422 



198 

 399 



434 

 394 

 208 

 196 



200 

 203 

 211 

 212 

 383 

 198 

 208 



206 



199 



202 



96 



107 



9 



366 



14 



273 



278 

 276 

 273 

 283 



