be owing, that the windward side of a reef exposed to the open sea, is generally, if not always the highest part, and rises almost perpendicular, sometimes from the depth of 200, and perhaps many more fathoms.  To be constantly covered with water, seems necessary to the existence of the animalcules, for they do not work, except in holes upon the reef, beyond low-water mark; but the coral sand and other broken remnants thrown up by the sea, adhere to the rock, and form a solid mass with it, as high as the common tides reach.  That elevation surpassed, the future remnants, being rarely covered, lose their adhesive property; and remaining in a loose state, form what is usually called a key, upon the top of the reef.  The new bank is not long in being visited by sea birds; salt plants take root upon it, and a soil begins to be formed; a cocoa nut, or the drupe of a pandanus is thrown on shore; land birds visit it and deposit the seeds of shrubs and trees; every high tide, and still more every gale, adds something to the bank; the form of an island is gradually assumed; and last of all comes man to take possession.

Half-way Island is well advanced in the above progressive state; having been many years, probably some ages, above the reach of the highest spring tides, or the wash of the surf in the heaviest gales.  I distinguished, however, in the rock which forms its basis, the sand, coral, and shells formerly thrown up, in a more or less perfect state of cohesion; small pieces of wood, pumice stone, and other extraneous bodies which chance had mixed with the calcareous substances when the cohesion began, were inclosed in the rock; and in some cases were still separable from it without much force.  The upper part of the island is a mixture of the same substances in a loose state, with a little vegetable soil; and is covered with the casuarina and a variety of other trees and shrubs, which give food to paroquets, pigeons, and some other birds; to whose ancestors it is probable, the island was originally indebted for this vegetation.

The latitude of Half-way Island, deduced from that of the preceding and following noons, is 10 deg. 8’ south, and longitude by time keeper corrected, 143 deg. 18’ east.  From the time of anchoring, to nine at night, there was a set past the ship to the north-east, of half a knot; it ceased for three hours, then recommencing at a slower rate, ran to the same point.  Thus far in the strait, the current had been found to run at the rate of fourteen miles a day to the westward; and the above set might have been an eddy under the lee of the reef, for it seemed too irregular to be a tide.

[SUNDAY 31 OCTOBER 1802]