- ^^ 



80 



HYDROGRAPHY. 



[Sect. III. 



directions for bringing up. 



- have been mentioned under 



tlie heaas of approaching a port, especially noting all 



c 



beacons, buoys, lighthouses, and landmarks &o 

 Art. 11). ' ^" 



Affix to these views of the land and sketches of the 

 fading marks. The geographical position, the time of 

 H. ^^ . F. and C, rise at springs and neaps, the low- 

 water standard of the port, &c., and the variation of the 

 compass, point out the best watering-places, and let all 

 bearings given be magnetic, and noted as such. 



Illations 



placed at the end of these directions. 



Tide Pole. 

 When a survey is determine 



2ft 



half an hour before to half 



should be registered every ten rmnutes.^ In addition to 



2f 



every half-hour to 



place of the water must be noted 

 facilitate the reduction of the soundings to the k,7i^tl^ 

 standard. The tide-gauge should be fixed in a well- 

 sheltered spot, with its zero such a depth as to ensure its 

 bemg below the low water at springs. When the pole is 

 properly secured and settled down, paint a mark in the 

 rocK corresponding with one of the divisions on the gauge, 

 and note which in your book, in case the pole should be 

 washed down. If you remain long enough in port, let 

 your observations be continued at least through an entire 



* See Forms. Nos. ? and s. 



1 



i 



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V 



M- 



* III-] 



l«nar 



mot 



!oW 



•,vater 



a 



ock 



level of I 



['.■ ■ ■ ■ 



by 



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r 



u 



:20ii: 



Let tb: 



Tlie bigh 

 [M and 



mg 



r 



*iinf\ 



the 



sliould be 

 with the { 



If tidr^ 



a Delt of I 



wlietlicr t 

 strength, 

 reefs and 



f 



aster th : 



la th 



e 



(No. 8) i 



other f Kc 

 Forfu 



24. Br 



^^ethr 



tide 



3 



ee 



aud 



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