It only now remains to notice the tides in the passage north of King Island. It is high-water on the full and change days at 1 o'clock; the stream begins to set to the South-West three hours and a half before high-water, running with a velocity of from 1 to 2 knots; past the Harbinger Rocks, however, it sweeps round to the South-South-West, sometimes at the rate of nearly two knots and a half.
Having alluded to the entrance south of King Island in an earlier part of the work, and as it is a passage I do not recommend, I shall not here enter into many details respecting it, further than to say that if a ship is obliged to enter Bass Strait by that entrance, she should keep to the southward of Reid's Rocks, passing close to the Black Pyramid, a dark rocky lump, 240 feet high, in latitude 40 degrees 28 minutes South, longitude 144 degrees 18 1/2 minutes East. This should be made bearing North-East 3/4 East, which would keep ships clear of the Conway and Bell sunken rocks, the former and outermost of which lies fifteen miles North 83 degrees West from it. The cross set of the tides should be particularly borne in mind, and likewise their strength, which is sometimes 3 knots. The stream to the South-West by South begins at 3 P.M. on the full and change days, or three hours and a half before high-water. The depth in the south entrance varies from 35 to 38 fathoms.
I shall perhaps make this note more useful by stating that January and February are the best months for making a passage to the westward through Bass Strait; although easterly winds blow on some rare occasions at other times, but these are mostly gales, and generally terminate in a breeze from the opposite quarter, having much the character of a rotatory gale, one of which I have described in an early part of the work. The gales that chiefly prevail in this Strait begin at North-North-West, and gradually draw round by West to South-West, at which point they subside; but if the wind, before it has so much southing, veer again to the northward of west--or backs, as it is expressed--the gale will continue; but its duration may be told by the barometer, as it is seldom fine when it registers less than 29.95, and bad weather is certain if it falls to 29.70.
N.B. The courses recommended in this note are marked in the chart accompanying the work.)
Our anchorage this time was on the south side of the singular natural fortification I have before described; and whilst there we were placed in some anxiety by being caught in a gale from the eastward. The holding-ground, however, being very good, and a strong outset sweeping out of the bay round the south side of the head, lessened the strain on the cables. The sudden appearance of this breeze, and the manner in which it was succeeded by another from the westward, afforded additional evidence of how necessary it is for anchorages in this strait to be sheltered from both quarters. A jetty, which has been run out by the Company, forms available shelter at high-water for vessels of nine and ten feet draught.
On the 20th of January, having made a valuable set of tidal* and other observations, and arranged with Mr. Forsyth to meet him at Hobart, we sailed in the afternoon, and next morning passed half a mile from the south side of the Pyramid, in 35 fathoms. It is a light-coloured mass, worthy of its name, 300 feet high. From thence we steered towards Cape Frankland, the North-West point of Flinders Island, which we had still to examine, decreasing the soundings gradually to 26 fathoms within two miles and a half to the West-North-West of it. We could see nothing of the sunken rock said to lie two miles west from the above headland; yet, as we have not exactly gone over the spot, it has been marked in the chart with a p.d. against it.
(*Footnote. The line of high-water at the full and change is 11 hours 40 minutes, when the rise is 9 feet.)
HUMMOCK ISLAND.
I was also anxious to obtain a distant seaward view of Hummock Island,* which affords the best shelter for ships in westerly winds.