248 THE INFLUENCE OF INANIMATE SUREOCNDINGS. 



it neai'S the land, but very equably and bardly peroeptibl}' to 

 the eye, till it breaks at last on. the wall of the outer reef with 

 a roar ; but as this wall does not rise abruptly from the deep 

 purple sea, as on the western reef, a phenomenon here becomes 

 visible which may frequently be observed on sloping coasts ; a 

 second line of breakers succeeds the outer line, nearer in, and 

 often even a third. This phenomenon is very familiar to the 

 natives; to escape the danger of their boats filling at the 

 second or third line of breakers, after crossing the first row of 

 breakers, they shove the boat with long poles as quickly as 

 they can over the outer level of the reef, so as to pass as rapidly 

 as possible the two dangerous lines of sm-f lying beyond. On 

 the western reef, on the other hand, there is never more than 

 a single broad belt of breakers. 



These facts alone suffice to prove that the outward slope of 

 the eastern reef is quite gradual. I investigated the matter 

 very carefully, and with the express view of forming my own 

 judgment on the assertion I had so often read that, on the 

 weather side of a reef, the fall was always very abrupt. But 

 my own investigations were certainly not favourable to this 

 statement ; on the contrary I saw, as I have said, that even at 

 some thousand paces from the shore the species of corals were 

 still easily distinguishable, and at a distance even of from two to 

 three sea-miles from the outer reef the water was stiU much 

 lighter in colour than in the channel between Kriangle and 

 KosRol, where, according to the soundings of navigators, 

 it is about sixty fathoms deep. This exactly agreeji with those 

 observations as to Kossol and Kriangle which I mentioned 

 before, without, however, adding much to thoir significance. 

 But I may now assert with the utmost decisiveness that every- 

 where in the northern part of this group of islands the eastern 

 slope outside the barrier reef is particularly gentle, while that on 

 the west is so precipitous that, at a few hundred paces outside 

 the reef, the bottom is quite invisible. 



The facts here adduced are wholly irreconcilable with 

 Darwin's theory of subsidence. Before entering on that ques- 

 tion more in detail it will be well to make an equally exact survey 

 of the reefs lying to the south. 



