﻿Staff-Comr. H. Eosken, R.N.— Notes on Coral Reefs. 71 



Continuing in this way, a number of cases might be considered 

 which would show us that in some cases the depth of ice below the 

 surface of the water is eight times that which is above, in some 

 cases less than eight times, and in other cases greater than eight 

 times. 



What now remains to be done is to take the case which seems to 

 be, for the generality of icebergs, the most probable one. This 

 I believe to be the case where we have a pinnacle standing on a foot 

 or pedestal, or in the limiting case a cone floating with its apex 

 upwards. In this case the height above the surface of the loater toill 

 he generally greater than the depth lohich is heloio. Until future 

 observations show this view to be a wrong one, I think I shall 

 be justified in keeping to the above result. 



VII. — Notes on Cokal Eeefs. 

 By Staff-Commander Henry Hosken, E.N., H.M.S. Pearl. 



[Comnmnicated by E. H. Scott, F.R.S., Director of the Meteorological Office.] 



HAVE to thank you for your kind letter of the 24th of December, 

 1875 ; it aifords me great satisfaction to hear that my remarks 

 about the New Hebrides ^ have interested you. 



Thinking that my observations on the soundings that T obtained 

 off the east end of Vanikoro Island, Santa Cruz Group, might be 

 useful, I propose to forward a copy of them, together with tracings, 

 with the next Log that I shall complete and send into office ; the 

 originals were forwarded to the Hydrographical Department on the 

 31st December, 1875. A new edition of the Chart No. 986 with 

 corrections has since been issued. 



The chief interest of this discovery is not so much in its hydro- 

 graphical importance, as in its connexion with the probable alteration 

 of the geological formation of these reefs, or else, allowing that they 

 existed at the time of the Survey, it shows that this " Barrier Keef " 

 is not so different from the general rule as was at first supposed, 

 when the Chart showed a gap of eight miles in the reef. 



Before our arrival at Vanikoro Island, Commodore Goodenough 

 and I had been remarking on the peculiarity of the apparent cessation 

 of the " Barrier Eeef " on the weather side of that island. 



The Pearl was taken into the anchorage of Ocili Harbour, Tevai 

 Bay, under sail, a strong Trade was blowing ; when nearly abreast 

 Dillon Head, and steering in on the course recommended, a shoal 

 spot, upon which the sea occasionally broke heavily, was seen ; this 

 was only cleared by about a ship's length ; particulars are given in 

 copy of remarks. The patch appeared to consist of live coral. 



Whilst the Pearl was steaming out, several soundings were 

 obtained, and much discoloured water seen over shoal-looking 

 ground, the description of which is given in Eemarks, and the 

 position shown in the tracings already alluded to. 



It had been Commodore Goodenough's intention to have taken 

 the Pearl inside the "Barrier Eeef," but eventually it was considered . 



1 See Geol. Mag. 1876, Decade II. Vol. III. p. 82. 



