COKAL REEFS. 361 



a copy of the Admiralty orders under which Captain Black- 

 wood sailed ; a perspicuous document, and excellent not only 

 in the explicit nature of the naval instructions, but also in 

 its humane and judicious inculcation of rules for intercourse 

 with the natives. The following are stated in this document 

 as the main objects of the expedition : 



The survey of the exterior or eastern edge of that vast 

 chain of reefs, which extend almost continuously from Break- 

 sea Spit to the shore of New Guinea : 



The thorough examination of all the channels through the 

 barrier chain, with detailed plans of those which offer a secure 

 passage, and the device of some practical means of marking 

 them by beacons of wood, stone, or iron : 



And the ascertainment of the safest channels by which 

 vessels coming from the eastward may pass through the 

 intricate reefs and islands occupying the mouth of Torres 

 Strait; and, in particular, a complete survey of the passage 

 called Endeavour Strait. 



These orders are closed by the following passage, which 

 well deserves every attention : 



But, wherever you go, we expect you to produce full and faithful 

 surveys of the places you visit. And we especially desire you not 

 to waste your time and means in what are called running surveys, 

 in which much work is apparently executed, but no accurate know- 

 ledge obtained, useful either to the mariner or geographer. What- 

 ever you do is to be done effectually. 



This is sound and vigorous instruction ; and applicable not 

 solely to voyages of discovery, but much more largely to all 

 great enterprises and objects of human pursuit. 



We must carry our readers somewhat farther into the de- 

 scription of this Great Barrier Eeef, not merely as forming 

 the main object of Captain Blackwood's expedition, but from 

 its being marked as the most singular and gigantic example 

 of its land on the surface of the globe. Among the various 



