The longitude of Cape Virgin Mary, which is the most essential point, as it determines the length of the straits of Magalhaens, is deduced from Lord Anson, who made 2° 30' difference of longitude between it and the Strait Le Maire. Now as the latter lies in 65° 22', Cape Virgin-Mary must lie in: 67° 52', which is the longitude I have assigned to it, and which, I have reason to think, cannot be far from the truth.
The strait of Magalhaens, and the east coast of Patagonia, are laid down from the observations made by the late English and French navigators.
The position of the west coast of America, from Cape Victory northward, I have taken from the discoveries of Sarmiento, a Spanish navigator, communicated to me by Mr Stuart, F.R.S.
Falkland Islands are copied from a sketch taken from Captain M'Bride, who circumnavigated them some years ago in his majesty's ship Jason; and their distance from the main is agreeable to the run of the Dolphin, under the command of Commodore Byron, from Cape Virgin Mary to Port Egmont, and from Port Egmont to Port Desire, both of which runs were made in a few days; consequently no material errors could happen.
The S.W. coast of Terra del Fuego, with respect to inlets, islands, etc. may be compared to the coast of Norway; for I doubt if there be an extent of three leagues where there is not an inlet or harbour which will receive and shelter the largest shipping. The worst is, that till these inlets are better known, one has, as it were, to fish for anchorage. There are several lurking rocks on the coast, but happily none of them lie far from land, the approach to which may be known by sounding, supposing the weather so obscure that you cannot see it. For to judge of the whole by the parts we have sounded, it is more than probable that there are soundings all along the coast, and for several leagues out to sea. Upon the whole, this is by no means the dangerous coast it has been represented.
Staten Land lies near E. by N. and W. by S., and is ten leagues long in that direction, and no where above three or four leagues broad. The coast is rocky, much indented, and seemed to form several bays or inlets. It shews a surface of craggy hills which spire up to a vast height, especially near the west end. Except the craggy summits of the hills, the greatest part was covered with trees and shrubs, or some sort of herbage, and there was little or no snow on it. The currents between Cape Deseada and Cape Horn set from west to east, that is, in the same direction as the coast; but they are by no means considerable. To the east of the cape their strength is much increased, and their direction is N.E. towards Staten Land. They are rapid in Strait Le Maire and along the south coast of Staten Land, and set like a torrent round Cape St John; where they take a N.W. direction, and continue to run very strong both within and without New Year's Isles. While we lay at anchor within this island, I observed that the current was strongest during the flood; and that on the ebb its strength was so much impaired, that the ship would sometimes ride head to the wind when it was at W. and W.N.W. This is only to be understood of the place where the ship lay at anchor, for at the very time we had a strong current setting to the westward, Mr Gilbert found one of equal strength near the coast of Staten Land setting to the eastward, though probably this was an eddy current or tide.
If the tides are regulated by the moon, it is high-water by the shore at this place on the days of the new and full moon, about four o'clock. The perpendicular rise and fall is very inconsiderable, not exceeding four feet at most. In Christmas Sound it is high-water at half past two o'clock on the days of the full and change, and Mr Wales observed it to rise and fall on a perpendicular three feet six inches; but this was during the neap tides, consequently the spring tides must rise higher. To give such an account of the tides and currents on these coasts as navigators might depend on, would require a multitude of observations, and in different places, the making of which would be a work of time. I confess myself unprovided with materials for such a task; and believe that the less I say on this subject the fewer mistakes I shall make. But I think I have been able to observe, that in Strait Le Maire the southerly tide or current, be it flood or ebb, begins to act on the days of new and full moon about four o'clock, which remark may be of use to ships who pass the strait.
Were I bound round Cape Horn to the west, and not in want of wood or water, or any other thing that might make it necessary to put into port, I would not come near the land at all. For by keeping out at sea you avoid the currents, which, I am satisfied, lose their force at ten or twelve leagues from land; and at a greater distance, there is none.
During the time we were upon the coast we had more calms than storms, and the winds so variable, that I question if a passage might not have been made from east to west in as short a time as from west to east; nor did we experience any cold weather. The mercury in the thermometer at noon was never below 46°; and while we lay in Christmas Sound it was generally above temperate. At this place the variation was 23° 30' E.; a few leagues to the S. W. of Strait Le Maire it was 24°; and at anchor, within New Year's Isles, it was 24° 20' E.
These isles are, in general, so unlike Staten Land, especially the one on which we landed, that it deserves a particular description. It shews a surface of equal height, and elevated about thirty or forty feet above the sea, from which it is defended by a rocky coast. The inner part of the isle is covered with a sort of sword-grass, very green, and of a great length. It grows on little hillocks of two or three feet in diameter, and as many or more in height, in large tufts, which seemed to be composed of the roots of the plant matted together. Among these hillocks are a vast number of paths made by sea-bears and penguins, by which they retire into the centre of the isle. It is, nevertheless, exceedingly bad travelling; for these paths are so dirty that one is sometimes up to the knees in mire. Besides this plant, there are a few other grasses, a kind of heath, and some celery. The whole surface is moist and wet, and on the coast are several small streams of water. The sword-grass, as I call it, seems to be the same that grows in Falkland Isles, described by Bougainville as a kind of gladiolus, or rather a species of gramen* and named by Pernety corn-flags.