CHAP. VI.] RUNNING SURVEY 181 



what we have whilst beacon is being picked up, and will 

 furnish, enough to sound upon, and ensure filling up properly 

 and not crossing the old hne, for the distance between Beacons 

 I. and II. is obtained from the runs up and down. 



Whilst sounding up to II., the coast and topography are 

 shot in, and a rough sketch of the coast and hiUs is put into 

 the deck-book, which at the end of the fleet is sent down to 

 the officer in the chart-room for plotting. 



On passing close to Beacon II., put over logs and shape a 

 straight course roughly parallel again to the shore, until 

 abreast of Breastmark III., when stop, put over Beacon III., 

 and take angles as described at II. 



Turn outwards again and get Corner Fix III., and run back 

 parallel to old course to Intermediate Fix II., which, and all 

 subsequent intermediate fixes, should be at two-thirds of the 

 distance back. At this position it is important to be able 

 to get a good fix on the points of Fleet II. — in other words, 

 that the angle between the Breastmark II. and Beacon II. 

 shall be over 30°. It matters not whether Beacon II. is outside 

 or inside of Breastmark I. 



On dropping a beacon, the essential angles are the primary 

 and breastmark of the fleet, and the other beacon, the 

 provisional breastmark ahead and the middle primary 

 ahead. 



At the corner fixes, obtain the same angles as in dropping 

 the beacon, only using the beacon just dropped instead of the 

 other beacon. Take elevations for heights. 



At the intermediate fixes, get the primary and breastmark 

 of the fleet, the beacon towards which you are running, the 

 breastmark of that beacon, and the next primary behind. 



On picking up a beacon, get the primary and breastmark 

 of the fleet ahead, the other beacon, the breastmark abreast 

 of you, and, if visible, the breastmarks behind, as well as 

 primaries. 



It will not always, of course, be possible to distinguish the 

 breastmarks of fleets so far ahead and astern, but whenever 

 possible they should be taken, as points so far distant give 

 excellent zeros for plotting, and the bearing is preserved. 

 Any conspicuous object, whether used as breastmark or not, 

 will answer this purpose. 



