APPENDIX A. SECTION 3.
DESCRIPTION OF THE WINDS AND WEATHER, AND OF THE PORTS AND COAST BETWEEN WESSEL'S ISLANDS AND CLARENCE STRAIT.
In the sea that separates the land of New Guinea and the islands of Timor Laut and Arroo from the north coast of Australia, the winds are periodical, and are called the east and west monsoons, for such is their direction in the mid-sea. Near the Coast of New Holland the regularity of these winds is partly suspended by the rarefied state of the atmosphere; this produces land and sea-breezes, but the former are principally from the quarter from which the winds are blowing in the mid sea. The usual course of the winds near the coast in the months of April, May, and June, is as follows: after a calm night, the land-wind springs up at daylight from South or South-South-East; it then usually freshens, but, as the sun gets higher, and the land becomes heated, gradually decreases. At noon the sea-wind rushes in towards the land, and generally blows fresh from East; at sunset it veers to the North-East, and falls calm, which lasts the whole night, so that if a ship, making a course, does not keep at a moderate distance from the land, she is subject to delay; she would not, however, probably have so fresh a breeze in the day time. Later in the season of the easterly monsoon, in August, September, and October, calms are frequent, and the heat is sultry and oppressive; this weather sometimes lasts for a fortnight or three weeks at a time. The easterly monsoon commences about the 1st of April, with squally, rainy weather, but, in a week or ten days, settles to fine weather and steady winds in the offing, and regular land and sea breezes, as above described, near the coast. It ceases about the latter end of November or early part of December; the westerly monsoon may then be expected to blow strong, and perhaps with regularity. This is the rainy season, and is doubtless an unwholesome time; Captain Flinders' crew experienced much sickness in his examination of the Gulf of Carpentaria during this monsoon, but, when upon the western side of the gulf, he thought that the fine weather then experienced might be occasioned by the monsoon's blowing over the land. In January and February the monsoon is at its strength, but declines towards the end of the latter month, and in March becomes variable, with dark, cloudy, and unsettled weather; the wind is then generally from the South-West, but not at all regular.
The current sets with the wind, and seldom exceeds a knot or a knot and a half per hour; between Capes Wessel and Van Diemen it is not stronger, and its course in the easterly monsoon, when only we had any experience of it, was West: the strength is probably increased or diminished by the state of the wind.
The tides are of trifling consequence; the flood comes from the eastward, but rarely rises more than ten feet, or runs so much as a mile and a half per hour. High water takes place at full and change at Liverpool River, and Goulburn Island at six o'clock, at the entrance of the Alligator Rivers in Van Diemen's Gulf, at 8 hours 15 minutes, and at the south end of Apsley Strait at 3 hours 25 minutes.* The flood-tide comes from the eastward, excepting when its course is altered by local circumstances; the rise is not more than eleven feet at the springs.
(*Footnote. In St. Asaph's Bay, Lieutenant Roe found high-water take place at full and change at 5 hours 45 minutes; and in King's Cove at 5 hours 15 minutes; at the latter place it rose fourteen feet.)
The variation of the compass in this interval is scarcely affected by the ship's local attraction. Off Cape Wessel it is between 3 and 4 degrees East; at Liverpool River about 1 3/4 degrees East, at Goulburn Islands 2 degrees East, and off Cape Van Diemen, not more than 1 1/2 degrees East.
The dip of the south end of the needle at Goulburn Island was 27 degrees 32 1/2 minutes.
When the survey of the Gulf of Carpentaria was completed by Captain Flinders, his vessel proved to be so unfit for continuing the examination of the north coast, that it was found necessary to return to Port Jackson; and as he left it at the strait that separates Point Dale from Wessel's Islands, which is called in my chart BROWN'S STRAIT, he saw no part of the coast to the westward of that point, nor did he even see Cape Wessel, the extremity of the range of Wessel's Islands, which terminate in latitude 10 degrees 59 1/4 minutes, and longitude 135 degrees 46 minutes 30 seconds. The group consists of four islands, besides some of smaller size to the southward of the northernmost, and also a few on the eastern side of Brown's Strait; one of which is Cunningham's Island, of Captain Flinders. CUMBERLAND STRAIT is in latitude 11 degrees 25 minutes, longitude 135 degrees 31 minutes.