CRUISE OF THE "ALERT." 



INTRODUCTION. 



IN the summer of 1878 it was decided by the Lords of the 

 Admiralty to equip a vessel for the threefold purpose of 

 continuing the survey of the Straits of Magellan, of investigating 

 the nature and exact position of certain doubtful reefs and islands 

 in the South Pacific Ocean, and of surveying a portion of the 

 northern and western coasts of Australia. The special object of 

 the Magellan portion of the work was to make such a detailed 

 survey of the sheltered channels extending southward from the 

 Gulf of Penas to Port Tamar as would enable vessels to pass 

 from the Straits to the Pacific, and vice versa, without having to 

 encounter the wild and inhospitable outer coasts presented by the 

 chain of desolate islands here fringing the western coasts of South 

 America. It was also desirable that additional anchorages should 

 be found and survc}-ed, where vessels might lie in safety while 

 v.'aiting for the cessation of a gale, or for a favourable tide to help 

 them through the straits. The surveys made by the Adventure 

 and Bcag/c in 1826-36, and by the Niissart in 1866-9, were 

 excellent so far as they went, and so far as the requirements of 

 their times were concerned ; but the great increase of ocean 

 navigation within the last few years had rendered it necessary 

 that the charts should contain more minute survcj-s of certain 



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