The average range of the thermometer on that part of the coast, between the North-West Cape, and the meridian of 120 degrees east longitude, during the above-mentioned period, was between 75 degrees in the middle of the day, and 60 degrees at night, on board the ship, and the general course of the wind as follows, viz.

About sunrise, or sometimes a little before that, a breeze springs up between South and South-South-East and draws to the eastward as the sun rises, rapidly increasing in strength, and between 8 and 11 A.M. often blows a fiery breeze; towards noon it moderates, and rarely lasts until 2 P.M., after which there is a light breeze from North-East which at times reaches to north; the nights are mostly calm, or a light breeze from the south-westward; at the full and change of the moon, we found the south-easterly winds stronger than at other times; dews at times very copious.

All this part of the coast is subject to the effects of mirage, by which its outline is at times very much distorted, but generally speaking it ceases with the strength of the breeze, and as the sun attains a little altitude.  When the effects of mirage was observed in the morning, I noticed that the winds were much lighter throughout the day, than usual.

During this part of the year, the atmosphere is clear, with a cloudless sky, and the coast is exempted from the violent East-South-East squalls, that are of frequent occurrence, while the sun is in the southern hemisphere, and the land consequently very much heated.

Towards the latter end of August, and in September, the winds are not quite so regular, and there are occasional intervals of two or three days of westerly winds.

That part of the North-West coast between the North-West Cape, and the 116th degree of east longitude, seems to be subject to westerly winds at all times of the year.  The prevailing southerly winds that blow along the west coast, appear to draw round the Cape, and follow the direction of the land.  Between April and October (when the easterly monsoon is blowing to the northward) they are generally to the southward of west, or between that point and South-West, but during the westerly monsoon between West and North-West.

Upon getting to the westward of the North-West Cape, the wind becomes more southerly, and draws to the eastward of south as the distance from the land increases, and will be found varying between South-South-East and East-South-East, generally speaking as far south as the parallel of 30 degrees of south latitude, after which it is mostly to the westward of south, so that ships making a passage to the southward, along the west coast of New Holland, will rarely be able to make any easting, before reaching that latitude, particularly during the summer months.  In the winter a ship may occasionally make a quick passage to the southward, if happening to be upon the coast during a northerly gale; and as all these gales are preceded by North-East winds, a sufficient offing may be gained to enable her to run on, when the wind gets to the southward of west.