CHAP. VII.] COAST-LINING 189 



We plot C and D by their distances on their respective hnes 

 from A and B. We then walk round the bay, sketching it 

 in, and can get an angle at C, from A to D, as another check, 

 and any other angles to assist in sketching in details. 



The coast-hner will generally be responsible for all the details Coast- 

 of topography close to the coast such as follow, the scale of do'^Topp. 

 the chart being taken into consideration as to with what degree graphy 

 of accuracy detail can be laid down. ti^g shore. 



Heights of cliffs must either be measured with a lead-line, 

 or by getting an elevation to some definite point, which must 

 afterwards be fixed, from one of the stations, or may merely 

 be estimated and entered in the angle-book. 



The height of a cliff or rock can be readily calculated on the 

 spot from an angle, by the formula : 



Angle in seconds x distance in miles 

 Height in feet = — . 



Cliffs have generally to be exaggerated on the chart, to show 

 distinctly. The height in feet should be written against them. 



Whilst coast-hning, the height of small hillocks, rocks, 

 etc., along the shore can often be sufficiently approximately 

 measured in the following manner, viz. : 



Standing at the high- water line, notice when the sea horizon 

 cuts the slope of the hillock or rock, etc. ; walk to this spot, 

 stand there, and repeat the operation as often as necessary 

 until the summit is reached. The number of times this is 

 repeated x height of observer's eye above the ground, + the 

 odd feet of its summit above the last level observed, = height 

 required. 



The directions of lower parts of streams, or rivers, must 

 either be walked up, and fixed, a certain distance back, or 

 can merely have their entrances fixed, and an angle taken up 

 for their general direction. 



Lower spurs of abrupt hills must be sketched in, assisted 

 by angles to them from different points. 



Houses standing back from the shore must be put in. These 

 can usually be fixed by angles to them without visiting them, 

 unless it is necessary to get their dimensions, names, etc., or 

 perhaps to ascertain if a good well or spring of water may be 

 near, that would do for watering on an emergency. 



