LABRADOR I^ 



Kikkitavak. With a boat running a sentry ahead the ship passed 

 through the Taktok Tickle and then north-westward for the 

 channel between Palungitak and Paul Islands, where she came to 

 anchor and a boat was sent to sound out and buoy the channel 

 through. 



The area where the survey of the coast was to be commenced 

 had now been reached, and all eyes on the bridge were alert to 

 see any site ashore which would be suitable for the base line 

 measurement. 



There are three basic essentials to an original survey. First a 

 suitable stretch of land, at least half a mile long, must be found 



The Submarine Sentry 



and levelled. On this a base line will be carefully measured with 

 steel tapes to establish the scale of the survey. Next the geograph- 

 ical position on the earth's surface of some point within the area 

 of the survey must be fixed by taking star sights, usually with a 

 surveyor's astrolabe. The position of this point in relation to 

 the base line can be found by measuring the angles of the triangle 

 it forms with the base line. But the orientation of the survey still 

 remains to be found. In other words the direction on the earth's 

 surface of the base line (or any other line on the survey) is still 

 unknown, and this is established by measuring the angle between 

 a line joining any two points and the sun (or a star), knowing 



