INTRODUCTION. 3 



faint idea of the singular aspect of one of these 

 lagoon-islands. Whitsunday Island is of small size, 

 and the whole circle has been converted into land, 

 which is a comparatively rare circumstance. As the 

 reef of a lagoon-island generally supports many sepa- 

 rate small islands, the word 'island,' applied to the 

 whole, is often the cause of confusion ; hence I have 

 invariably used in this volume the term ' atoll,' which 

 is the name given to these circular coral formations by 

 their inhabitants in the Indian Ocean, and is syn- 

 onymous with 6 lagoon-island.' 



Barrier reefs, when encircling small islands, have 

 been comparatively little noticed by voyagers; but 



No. 2. 



they well deserve attention. In their structure they 

 are little less marvellous than atolls, and they give a 

 singular and most picturesque character to the scenery 

 of the islands they surround. In the accompanying 

 sketch, taken from the Voyage of the Coquille, the reef 

 is seen from within, from one of the high peaks of Bo- 



B 2 



