never exceeded a quarter of an hour, and the western stream begins 0 hours 30 minutes after low-water at springs, and 0 hours 50 minutes after it at neaps; whilst the eastern begins 0 hours 40 minutes after high-water at springs, and 0 hours 10 minutes before it at neaps.  The velocity of the stream was from one to three knots, the strongest being the ebb, which at springs and with a strong westerly breeze attains a strength in the middle of the strait of nearly four knots, and causes, when opposed to the wind, a high-topping sea, dangerous for small craft.

Whilst in other respects the tides are the same, the time of high-water at Preservation Island, though only at the northern side of the strait, is 1 hour 15 minutes later than at Swan Island.  This great difference is caused by the influence of the flood-stream out of Franklin Channel and from the northward along the west side of Flinders Island.  The flood-streams setting to the westward through Banks Strait, and to the south-westward past the north-west end of Flinders, meet about ten miles to the westward of the Chappell Isles, when their united stream curves round by south to west, becoming gradually weaker, and soon after passing the mouth of the Tamar ceasing to be felt at all, leaving in the middle of Bass Strait a large space free from tidal influence as far as the production of progressive motion is concerned, that given to it from the entrances being neutralized by their mutual opposition.  There is, however, an easterly current of nearly a knot an hour, in strong westerly winds.  The meeting of the tides on the west side of Flinders also leaves a space, close to the shore near the centre, free from any stream.  At the eastern entrance of Franklin Channel there is also a meeting of the flood-streams, one coming from North-North-East and the other from South-East.)

Whilst at this anchorage two boats belonging to the whaling station on Wilson’s Promontory passed on their way to Hobart, which they reached in safety.  They made the passage, hazardous for boats, across the strait by touching at Hogan and Kent Groups and so over to Flinders Island.

CAPE PORTLAND.

Leaving, we beat through between Swan Islands and the main, which we found to be a good channel,* a mile and a half wide, with an average depth of ten fathoms.  After passing the western islet the south side of the strait should be given a wide berth, particularly on approaching Cape Portland, off which some islets with foul ground and a sunken rock at their extreme, extend two miles and a half.  The summit of Swan Island, bears South 75 degrees East and Mount Cameron South 2 degrees East from the outer edge of this danger; which masters of vessels should remember, both in reaching to the southward in the strait, and in running for it from the westward.

(Footnote.  Mount William bearing South 40 degrees East leads into the western entrance.)

PRESERVATION ISLAND.