Between the parallels of 40 and 45 degrees they meet much bad weather, as it is generally blowing strong with a heavy sea; but between 45 and 50 degrees the weather is much more settled, and finer. November is said to be generally the finest of the summer months, the winds are mostly moderate, and the weather more settled than at other periods.
Two gales that were experienced by the Beagle in November 1837, between the islands of St. Paul and Amsterdam and Swan River, will serve to show the different effects upon the barometer by gales from opposite quarters, one being from North-West and the other from South-East.
On November the 1st, the barometer stood at 29.90, having been gradually rising for some days previous to that, and the wind had been fresh between north and west. After 8 P.M. on the 1st, the mercury began to fall, and on the 2nd, the wind was strong from North-North-West--barometer falling all day. During the night it blew a heavy gale, and the barometer fell to 29.34. On the morning of the 3rd the wind veered to the westward, and the mercury began to rise, the weather also became more moderate, and gradually fine.
On the 8th of the same month, the barometer was 30.05 at 8 P.M. with fine weather, wind South-East by East, it then commenced to fall, and at 8 P.M. on the 9th was 29.80, and blowing a heavy gale at South-East, which continued all night, and until 8 P.M. on the 10th, at which time it became more moderate, and the barometer began to rise.
What a different effect these gales had on the barometer; that from the North-West causing the mercury to fall nearly 6-tenths, whereas, the last, from South-East only lowered it 2-tenths, and 5-hundredths; they were of equal strength and duration, and both accompanied by heavy rain.
ON THE NORTH-WEST COAST OF AUSTRALIA.
The great extent of the North-West coast of Australia, lying as it does between the parallels of 12 and 22 degrees of south latitude, no doubt subjects it to a variety of winds and weather, that is not experienced on the north coast; although, on that part of it north of the parallel of 15 degrees, there is probably much similarity.
As I cannot speak with certainty of the winds and weather that prevail on this extent of coast, at all seasons of the year, the following remarks will be confined to such portions of it as were visited by the Beagle, and will apply only to the particular seasons in which she was employed there.
To the eastward of the meridian of 123 degrees east longitude, and at a short distance from the land, the east and west monsoons will be found regular; but the easterly monsoon is very light to the southward of 13 degrees latitude.