CHAP. VIII.] SOUNDING 199 



numerals, and minutes should be entered from time to time, 

 to know the reduction for tide ; the sounding at the fix goes 

 on the extreme right, and subsequent soundings up to the 

 next fix, in a row underneath, thus : 



X. 14 Pagoda 28° 31' Mat 62° 14' Can 7| 



7| 8 X X 81 9 X X 10 X 

 s m m 



23° 02' „ 60° (»8' „ 11 



Pea 41° 17' „ m 



The cross ( x ) signifies the same sounding as before ; and ah Casts 

 it may here be mentioned that all soundings must be put down^ *° 3^® 

 even though there may not be room for half of them eventually ; 

 as, the man heaving regularly, if all his casts are not registered, 

 the change of fathom will not come in its true place when 

 interpolating between the fixes. 



Space must be left under each line for the soundings, as Space for 

 reduced to low-water, to be written in in red ink. Reducing. 



A sliding scale for the reduction of soundings has been 

 devised by Lieutenants Helby and Craven, which avoids the 

 liability of arithmetical errors. This scale is supplied to 

 surveying ships. 



A check angle should be taken from time to time, to make check 

 certain that things are right, as is noted above at the last cast, ■^-'^sies. 

 in the example Can to Pea. This is especially necessary at 

 the commencement of work with new points, as mistakes will 

 occur in plotting points occasionally. A check will show at 

 once if points are true and if the angles have been taken 

 correctly. 



Judgment is needed in selecting objects for check angles. 

 If badly selected, a satisfactory check on the position may not 

 be afforded by them. A sensitive angle should be chosen 

 connected with the middle object of the primary fix. 



The nature of the bottom must be taken every few casts. Nature of 

 and recorded, the officer having a look at it from time to time 

 himself, to make certain that the leadsman is calling the stuff 

 he brings up by its right name. For instance, many men 

 will insist on calling " stones " rock, which is, of course, quite 

 a different thine:. 



