On quitting Port Jackson, the course to be steered is N. E. by E. by compass, to longitude about 155½°, when the land will be fifty leagues off; then North, also by compass, as far as latitude 24°. Thus far no danger lies in the way; but there is then the _Cato's Bank_, a dry sand frequented by birds and surrounded with a reef (Atlas, Plate X), and further northward is _Wreck Reef_, both discovered in the future part of this voyage. Wreck Reef consists of six distinct patches of coral, extending twenty miles east and west; upon four of them there are dry banks, also frequented by birds, and the easternmost bank is covered with wiry grass and some shrubs, and is called _Bird Islet_. Their situations are these: Cato's Bank 23° 6' south, 155° 23' east Bird Islet 22 11½ 155 27 The bearing and distance of these dangers must be successively worked, and a course steered so as to leave them half a degree to the westward; but for fear of an error in the time keeper the latitude 23° 20' should not be passed in the night. It is better to make short tacks till daylight, than to heave to; and allowance should be made for a probable current of one mile an hour to the north-west. A good lookout must be constantly kept; and a confidential officer should now go to the masthead every two hours in the day and to the fore yard at night, to listen as well as look; for in dark nights the breakers may often be heard before they can be seen. It will not be amiss, if the time of the day be favourable, to make Bird Islet, which is well settled, in order to see how the longitude by time keeper agrees; and should it err, the difference, or more, must be added to, or subtracted from its future longitudes; for it is most probable that the error will continue to augment the same way, more especially if the time keeper be a good one. [TORRES STRAIT. SAILING DIRECTIONS.] (Atlas, Plate I.) Having passed Wreck Reef, there are no other _known_ dangers near the route for Torres' Strait, till we come to _Diana's Bank_; but as others may exist, it will be prudent to lie to, or preferably to make short tacks in the night, during the rest of the passage to the Strait. In light nights, however, and moderate weather, there would be not much risk in closely following the Cumberland's track, carrying no more sail than will allow of the ship being conveniently hauled to the wind; but if an unusual number of boobies and gannets be seen in the evening, there is strong suspicion of a bank and reef being near; and the direction which the birds take, if they all go one way as is usual in an evening, will nearly show its bearing. The longitude of Diana's Bank, according to M. de Bougainville, is 151° 19' from Greenwich; but his longitude at the New Hebrides, some days before, was 54' too far east, according to captain Cook; and it is therefore most probable, that Diana's Bank lies in 15° 41' south, 150° 25' east.