1897-98-] Corals and Coral-Islands. 323 



spines, or the bright-blue starfish with its finger-like arms 

 spread out. 



Outside the barrier reef the long ocean swell rolls in, wave 

 after wave, each gradually rearing its crest higher and higher, 

 until it curls over, and falls like an avalanche of white 

 foam, with a thunderous roar, upon the flat coral-reef. The 

 native oarsmen take a special delight in steering as near to 

 the breakers as possible : they know exactly how near they 

 may venture with safety. But woe betide the canoe that is 

 carried by the swell broadside on in one of these huge 

 breakers ! The canoe and its occupants are rolled over and 

 over, until they are at last dashed with terrific force against 

 the sharp points of the outer reef. 



To what depths the solid coral-reefs may go is not yet 

 known ; but the first thing that raised in Darwin's mind the 

 suspicion that these coral-islands are sinking into the ocean- 

 bed was the deep soundings he obtained quite near the outside 

 of the coral rim in some of the atolls he visited. In his study 

 of the subject, Darwin started the theory that " the original 

 coral-reef gradually subsided, and the coral polyp, which is 

 unable to live at more than a certain depth below the water, 

 is kept perpetually rebuilding on the surface." Dr John 

 Murray, on the other hand, asserted that " the ocean-floor has 

 risen owing to the heaping up of the remains of marine organ- 

 isms, and the coral-builders have lived and worked on these 

 elevated banks." In order to test the truth of Darwin's 

 theory, an exploring party was organised some few years ago by 

 the Eoyal Society of London. After they had made some 

 inconclusive observations, an expedition was despatched from 

 Sydney, consisting of Professor T. E. David of Sydney Uni- 

 versity, Mr George Sweet, Fellow of the Geological Society, 

 and six trained diamond- drillers. The party left Sydney in 

 June 1897, and ultimately chose for their purpose the island 

 of Funa Futi, in the Ellice group, lying 600 miles due north 

 of Fiji. The island is from ten to fourteen miles in diameter, 

 and is well supplied with cocoa-nut trees, which furnish the 

 inhabitants with their main food-supply. As soon as the 

 party landed they were lodged in bungalows in the native 

 village, on the inner rim of the coral-reef. They at once 



