Thursday, 23rd August, 1770
In the P.M. had little wind and variable, with which and the tide of flood we kept advancing to the west-north-west; depth of water 8, 7, and 5 fathoms. At half past 1 the pinnace, which was ahead, made the signal for shoal water, upon which we tacked and sent away the yawl to sound also, and then tacked again, and stood after them with the ship; 2 hours after this they both at once made the signal for having shoal water. I was afraid to stand on for fear of running aground at that time of the tide, and therefore came to an anchor in 1/4 less 7 fathoms, sandy ground. Wallace’s Islands bore south by west 1/2 west, distant 5 or 6 miles, the islands to the northward extending from north 73 degrees east to north 10 degrees east, and a small island just in sight bearing north-west 1/2 west. Here we found the flood tide set to the westward and ebb to the contrary. After we had come to anchor I sent away the master with the long boat to sound, who, upon his return in the evening, reported that there was a bank stretching north and south, upon which were 3 fathoms water, and behind it 7 fathoms. We had it calm all night and until 9 in the morning, at which time we weighed, with a light breeze at south-south-east, and steered north-west by west for the small island above mentioned, having first sent the boats ahead to sound; depth of water 8, 7, 6, 5, 4, and 3 fathoms when upon the bank, it being now the last quarter ebb. At this time the northernmost islands we had in sight bore north 9 degrees east; the south-west point of the largest islands on the north-west side of the passage, which I named Cape Cornwall, bore east; distant 3 leagues. This bank, at least so much as we sounded, extends nearly north and south, how far I cannot say; its breadth, however, is not more than 1/4 or at most 1/2 a mile. Being over the bank, we deepened our water to a 1/4 less 7 fathoms, which depth we carried all the way to the small island ahead, which we reached by noon, at which time it bore south, distant near 1/2 a mile; depth of water 5 fathoms. The northernmost land we had in sight (being part of the same chain of islands we have had to the northward of us since we entered the passage) bore north 71 degrees east; latitude in, by observation, 10 degrees 33 minutes south, longitude 219 degrees 22 minutes west. In this situation we had no part of the mainland in sight. Being now near the island, and having but little wind, Mr. Banks and I landed upon it, and found it to be mostly a barren rock frequented by birds, such as boobies, a few of which we shot, and occasioned my giving it the name of Booby Island. I made but a very short stay at this island before I returned to the ship; in the meantime the wind had got to the south-west, and although it blew but very faint, yet it was accompanied with a swell from the same quarter. This, together with other concurring circumstances, left me no room to doubt but we had got to the westward of Carpentaria, or the northern extremity of New Holland, and had now an open sea to the westward; which gave me no small satisfaction, not only because the danger and fatigues of the voyage were drawing near to an end, but by being able to prove that New Holland and New Guinea are two separate lands or islands, which until this day had been a doubtful point with geographers.
The north-east entrance of this passage or strait lies in the latitude of 10 degrees 27 minutes south, and in the longitude of 218 degrees 36 minutes west from the meridian of Greenwich. It is formed by the main, or the northern extremity of New Holland, on the south-east, and by a congeries of islands to north-west, which I named Prince of Wales’s Islands. It is very probable that the islands extend quite to New Guinea; they are of various extent both for height and circuit, and many of them seemed to be indifferently well clothed with wood, etc., and, from the smokes we saw, some, if not all of them, must be inhabited. It is also very probable that among these islands are as good, if not better, passages than the one we have come through, although one need hardly wish for a better, was the access to it from the eastward less dangerous; but this difficulty will remain until some better way is found out than the one we came, which no doubt may be done was it ever to become an object to be looked for. The northern extent of the main or outer reef, which limit or bounds the shoals to the eastward, seems to be the only thing wanting to clear up this point; and this was a thing I had neither time nor inclination to go about, having been already sufficiently harassed with dangers without going to look for more.
This passage, which I have named Endeavour Straits, after the name of the ship, is in length north-east and south-west 10 leagues, and about 5 leagues broad, except at the north-east entrance, where it is only 2 miles broad by reason of several small islands which lay there, one of which, called Possession Island, is of a moderate height and circuit; this we left between us and the main, passing between it and 2 small round islands, which lay north-west 2 miles from it. There are also 2 small low islands, called Wallace’s Isles, laying in the middle of the south-west entrance, which we left to the southward; the depth of water we found in the straits was from 4 to 9 fathoms. Everywhere good anchorage, only about 2 leagues to the northward of Wallace’s Islands is a bank, whereon is not more than 3 fathoms at low water, but probable there might be found more was it sought for. I have not been particular in describing this strait, no more than I have been in pointing out the respective situations of the islands, shoals, etc., on the coast of New Wales; for these I refer to the chart, where they are delineated with all the accuracy that circumstances would admit of.
With respect to the shoals that lay upon this coast I must observe, for the benefit of those who may come after me, that I do not believe the one half of them are laid down in my chart; for it would be absurd to suppose that we could see or find them all. And the same thing may in some measure be said of the islands, especially between the latitude of 20 and 22 degrees, where we saw islands out at sea as far as we could distinguish anything. However, take the chart in general, and I believe it will be found to contain as few errors as most sea charts which have not undergone a thorough correction. The latitude and longitude of all, or most of, the principal headlands, bays, etc., may be relied on, for we seldom failed of getting an observation every day to correct our latitude by, and the observations for settling the longitude were no less numerous, and made as often as the sun and moon came in play; so that it was impossible for any material error to creep into our reckoning in the intermediate times. In justice to Mr. Green, I must say that he was indefatigable in making and calculating these observations, which otherwise must have taken up a great deal of my time, which I could not at all times very well spare; not only this, but by his instructions several of the petty officers can make and calculate these observations almost as well as himself. It is only by such means that this method of finding the longitude at sea can be put into universal practice; a method that we have generally found may be depended upon within 1/2 a degree, which is a degree of accuracy more than sufficient for all nautical purposes. Would sea officers once apply themselves to the making and calculating these observations they would not find them so very difficult as they at first imagine, especially with the assistance of the nautical almanack and astronomical ephemeris, by the help of which the calculation for finding the longitude takes up but little more time than that of an azimuth for finding the variation of the compass; but unless this ephemeris is published for some time to come, more than either one or two years, it can never be of general use in long voyages, and in short voyages it’s not so much wanted. Without it the calculations are laborious and discouraging to beginners, and such as are not well versed in these kinds of calculations.