Page:A Voyage to Terra Australis Volume 2.djvu/296

From Wikisource
Jump to navigation Jump to search
This page has been proofread, but needs to be validated.
284
A VOYAGE TO
[East Coast.

usual limits of its force may be reckoned at from four, to twenty leagues from the land. Further out, there seems to be no constancy in the current; and close in with the shore, especially in the bights, there is commonly an eddy setting to the northward, from a quarter, to one mile an hour. It is in the most southern parts that the current runs strongest, and towards Cape Howe it takes a direction to the eastward of south; whereas in other places, it usually follows the line of the coast.

This exposition of the winds and currents beyond the tropic, points out the advantage of keeping at not more than three or four leagues from the land, when sailing northward and intending to touch on the coast; but in the winter season this must be done with caution, because gales then often blow from the eastward. A marine barometer will here be of signal advantage. If the weather be tolerably fine, and the mercury do not stand above 30 inches, there is no probability of danger; but when the mercury much exceeds this elevation and the weather is becoming thick, a gale is to be apprehended; and a ship should immediately steer off, until it is seen how far the wind veers to blow dead on the coast. With respect to a rise and fall in the marine barometer, it may be taken as a general rule upon this East Coast, that a rise denotes either a fresher wind in the quarter where it then may be, or that it will veer more to seaward; and a fall denotes less wind or a breeze more off the land; moreover, the mercury rises highest with a south-east, and falls lowest with a north-west wind; and north-east and south-west are points of mean elevation.

The shelter for ships which may be caught so suddenly as not to be able to clear the land, are these: Two-fold Bay, for vessels of four-hundred tons and under; Jervis and Botany Bays, Port Jackson, and Broken Bay; Port Hunter for brigs and small craft; Port Stephens; Shoal Bay for vessels not exceeding fifty tons; Glass-house Bay; and lastly Hervey's Bay, by going round Break-sea Spit. All these places will be found in Plates VI, VIII, IX, and X,