486 HYDROGRAPHICAL SURVEYING [chap. xxi. 



the plot and entered beforehand in the deck-book in Hght 

 pencil. If more than one angle to be observed by any 

 assistant, the order in which they are to be taken should be 

 known . 



3. All entries to be kept up to date in the deck-book. It 

 will be found advisable to keep separate pages of the deck-book, 

 which should be indexed, reserved for the entries at each 

 beacon, for doubtless we shall require to revisit the beacons 

 from time to time subsequentlj/ for various causes and much 

 confusion would then arise with entries relating to the same 

 beacon scattered throughout the book (see also Section XVIII.). 



4. Some prearranged warning should be always given to 

 the engine-room, such as will ensure prompt obedience to the 

 telegraph. 



5. It may be necessary to wait before going up to a beacon 

 until any of the ships have quitted any beacon that they may 

 be then at, or will obviously reach before us, so that nothing 

 may be masked, a mutual arrangement that should be well 

 understood. 



With the Ship at the Beacon. — 1 . It will be found generally best 

 for the commanding officer to handle the ship entirely. His 

 attention being thus engaged, he will not therefore be available 

 to observe any but the less important angles, should we be 

 short-handed. 



2. With proper preparation, and given clear weather, the 

 time occupied at the beacon should not exceed two or three 

 minutes, during which it will generally be found best -(de- 

 pendent upon the circumstances of the tidal stream, wind, and 

 sea, etc.) to maintain the ship stationary, with the beacons 

 on the port side nearly abreast of the bridge, say from 15 to 

 5 yards distant (for reason, see later), the bearing of the beacon 

 and the subtended angle of the bamboo staff being observed 

 from time to time by the commanding officer, or a range- 

 finder used. 



With the bridge forward as is now general the risk of fouling 

 the beacon is very small, a slight movement of the engines and 

 helm being all that is required, whilst the beacon should not be 

 allowed to draw aft. 



It will be found advantageous to make it a practice to pass 

 the beacons on that side opposite to which the sounding gear 



