64 THE BERMUDA ISLANDS. 



one point to another. The depth of water in the Flatts Inlet, 

 which receives a strong tidal current from the outer lagoon and 

 from Harrington Sound, is much less to-day than it was in 

 the early part of the century, when the Inlet furnished a safe 

 anchorage to vessels of large draught. 



Mr. Bourne finds similar conditions to exist in the lagoons 

 of the Diego Garcia reef, and he entirely rejects the theory 

 that lagoons could have been primarily formed through solu- 

 tion. He shows that nowhere has the lagoon deepened since 

 the time when Capt. Moresby surveyed the region in 1837, but, 

 on the contrary, evidences of shoaling to the extent of a full 

 fathom on the south side are not wanting. It is also pointed 

 out that the depth of water in the lagoons of the various 

 islands which are associated with Diego Garcia is not propor- 

 tional to the size of the lagoon, as we should naturally expect 

 to find it in accordance with the theory of solution. This is also 

 true of the Bermudian waters, although their relations 

 somewhat differ from those of the Chagos Banks. Thus, 

 the depth of water in the comparatively small Harrington 

 Sound is measurably greater than that of the outer water, the 

 big lagoon; it is also much greater than we find it in the 

 superficially more extensive Castle Harbor. 



Experiments made to determine the solvent power of sea- 

 water show that the process of solution is a very' slow one. It 

 appears indeed incredible, in the face of such energetic solu- 

 tion as is presumed to exist in the upper waters of the ocean, 

 that any extensive organic accumulation could ever take place 

 over the floor of the sea, where the solvent power of the water 

 is materially increased through pressure, and still less possible 

 that any considerable foundation could be built up from it, or 

 irom the summit of only a moderately depressed mountain 

 peak. The fact that in so large a number of atolls the lagoons 

 are either entirely wanting, or are reduced to mere shallow 

 pans of water, also militates against the hypothesis of solution. 



With regard to the formation of the primary ring through 

 accelerated growth on the outer margin, as depending upon 



