OUTER ltOUTE. 



313 



dians of 150° and 157° E. long,, till it attains the 

 lat. of 20" S. From this point it runs to the N.W. 

 till it reaches 15° S. lat. and 1.50° or 152* E. long., 

 and then W.N.W. to the lat. IT in about 144° 

 E. long. Along this route there is a clear track, 

 from 60 to 100 miles in width, that is free from 

 reefs.* But outside of it, on cither hand, detached 

 reefs are known to be numerous, and there probably 

 exist many which are unknown. In this outer route 

 the sea is of great and almost unfathomable depth as 

 far as is known ; there is consequently no anchorage, 

 and whatever the circumstances, a ship must keep 

 under sail till she come up to the edge of the Great 

 Barrier, and pass through one of its openings into 

 the comparatively shallow and sheltered water inside 

 of it. One of the principal objects of our expedition, 

 was tu survc) the northern part of the Barrier reef, 

 so as to lay down the best openings, and to erect 

 some mark or beacon by which one at least of them 

 could be distinguished from the others. By means 

 of this beacon, any vessel pursuing the outer route, 

 that from bad weather or other causes was out in 

 her reckoning, would have a chance of learning her 

 true position, and which way she ought to proceed. 

 As we never saw any of the outside reefs, I shall not 

 attempt to describe them, but confine myself to an 

 account of the Great Barrier. 



* Mr. Evans, master of li.M.S. Fly, was kind enough to 

 give me this information, from a number of documents collected 

 and compiled by himself. 



