Between Cape Bougainville and Cape Voltaire is the ADMIRALTY GULF. It is twenty-nine miles wide and twenty-two deep, independent of Port Warrender. This gulf is thickly strewed with islands and reefs: a group off Cape Voltaire was seen by the French and named by them the INSTITUTE ISLANDS, the three principal of which, of flat-topped shape, are called Descartes, Fenelon, and Corneille; besides these the Montesquieu Group, and Pascal and Condillac Islands, were distinguished. On the eastern side of the gulf, near the shore, are OSBORN'S ISLANDS, which are high and rocky: the southernmost is remarkable for its steep, precipitous form, and for its resemblance to Mount Cockburn in Cambridge Gulf. There is also a conspicuous high bluff on the principal island, which appears to have been seen by the French. In the offing is CASSINI ISLAND; it is rather low and level, and surrounded by cliffs and rocky shores: on the eastern side are four sandy beaches, which are very much frequented by turtle: a reef projects off its north end for a mile and a half. The anchorage is good near the island, but the water is very deep. The situation of its centre is in latitude 13 degrees 55 minutes 5 seconds, and longitude 125 degrees 42 minutes. PORT WARRENDER is an excellent port, and affords good anchorage in the bay round Crystal Head, in which a vessel is quite land-locked; but equally secure anchorage may be had for five miles higher up the port, in from four to seven fathoms, mud. It extends for six miles farther, but the depth in some parts is not more than two fathoms. At eleven miles from the entrance, the port is separated into two inlets, which wind under the base of a dividing range of high, steep, and wooded hills; these run up for five miles higher, when they become mere mangrove creeks. There is probably another inlet on the east side of Port Warrender which we did not examine, since it appeared to be less considerable in size, and important in appearance, than the arm which we had examined. CRYSTAL HEAD is in latitude 14 degrees 28 minutes, and longitude 125 degrees 55 minutes 30 seconds. WALMESLY BAY appeared to be a good port also, but it is open to the eastward. We did not enter it. CAPE VOLTAIRE is the extremity of a promontory, extending for more than twenty miles into the sea, and separating the Admiralty Gulf from Montagu Sound. There is a flat-topped hill near its extremity, in latitude 14 degrees 14 minutes 30 seconds, and longitude 125 degrees 40 minutes 12 seconds; and, at three miles more to the southward, a peaked hill; its shores on either side are rocky, and indented by bays. At one part the width across to Walmesly Bay cannot be more than a mile and a half. The MONTALIVET ISLES, about six leagues from the main, consist of three rocky islands; they are visible for six or seven leagues from the deck: the north-easternmost is in latitude 14 degrees 13 minutes 40 seconds, longitude 125 degrees 19 minutes 30 seconds.