Discoveries in Australia Volume II Part 45

I have noticed, that when the seabreeze sets in from a point to the westward of South-West, it does not blow so strong, and generally lulls at sunset; but if more southerly, or from South-South-West, it is a fiery breeze, and often lasts until midnight.

During the prevalence of these strong seabreezes, communication between Gage Road and the sh.o.r.e is very inconvenient--particularly for laden boats.

In March, the seabreezes are not nearly so strong, but are generally moderate, and not unfrequently bring in thick misty weather from southwards, with drizzling rain.

Generally speaking, when the seabreezes are the strongest, the land winds are light, and vice versa.

I cannot speak from experience of the winds or weather during the month of April, at Swan River, but have been told that the seabreezes are moderate, and the land winds of longer duration; calms are frequent--and the weather altogether seems to indicate the breaking up of the summer season; light winds are occasionally felt from the northward, with a dull, gloomy appearance between that point and South-West.

May is the month in which the winter weather fairly sets in, and it rarely happens that the middle of this month pa.s.ses without the rains having commenced. This season seems to vary but little as to the time and manner of setting in--it is ushered in by blowing weather, from about North-North-East, the wind gradually veering round to the westward, as it increases in strength. The first of this weather usually lasts from a week to fourteen days; then comes an interval of fine weather, generally of a fortnight's duration, and sometimes a month; after which the rains set in more constant, and the intervals of fine weather are shorter; this weather lasts until October, and at times throughout that month.

During the intervals of fine weather the climate is delightful, and the country has a fresh and pleasing appearance; land and seabreezes are as regular as in summer, with the exception, that the latter are much more moderate.

The North-West gales that occasionally occur during the winter months, on the southern parts of the west coast of Australia, are probably felt as far north as Shark's Bay. They blow with great violence, and are accompanied by dark, gloomy weather, and rain. It is then unsafe to be near the land--as the gale that commences at North-North-East, invariably veers to the westward, making a lee sh.o.r.e of the whole line of coast, and between West-North-West and West-South-West blows the hardest.

Fortunately these gales give ample warning; the barometer always foretells their approach, and generally begins to fall three or four days before the commencement of the gale--besides which, there are other never-failing indications of a northerly wind, such as, the change of the current, which (owing to the prevailing southerly winds) usually sets to the northward, but runs strong to the southward during northerly winds--frequently preceding them, and giving more timely notice than the barometer.

A rising of the water is likewise a certain prognostic of a northerly wind; and has been invariably noticed, at Swan River, to precede all gales from that quarter--this, of course, can only be observed while at anchor on the coast.

Another, and perhaps equally certain sign of approaching bad weather, during the winter season (and which is almost certain to be from the northward) is the strength of the North-East winds--as it has been observed, that when the land winds blow strong, particularly from the North-East and the seabreezes are light, with a falling barometer, a gale from the northward will follow. Perhaps these latter remarks, are only applicable to that distance from the sh.o.r.e, where a s.h.i.+p will be within the influence of the land and seabreezes; but as I conceive the limit of that distance to be full 30 miles off sh.o.r.e, a notice of such a symptom of approaching bad weather, may not be altogether useless. I am of opinion, that land winds are at times felt as far off sh.o.r.e as the edge of soundings, which is not less than 30 miles, and generally between that and 40.

(In lat.i.tude 30 degrees 25 minutes South and 65 miles from the land, soundings were got from the Beagle, with 185 fathoms of line, upon a coral bottom. Between Swan River and Houtman's Abrolhos, soundings may be had at a greater distance from the land, than off any other part of the west coast.)

The North-West gales are of longer duration, in the lat.i.tude of Swan River, and south of that, than they are to the northward; they do not appear to be entirely confined to the winter months, as I am told that a very heavy one was experienced at Swan River, early in March, 1832, and on the 13th December, 1839, the Beagle experienced a strong breeze from the northward, while at anchor in Gage Road, in consequence of which, it was considered necessary to let go an extra anchor.

As it may be satisfactory to know more particularly the progress of these gales, and the effect they have upon the barometer and sympiesometer, I give the details of two that were experienced in H.M.S. Beagle, one at Swan River, in the beginning of June 1838, the other at Houtman's Abrolhos, in the beginning of May 1840; they may be taken as fair criterions of the strength and duration of these gales, the latter having been experienced, probably, within 5 degrees of their northern limit, and the former near the southern extreme of the west coast.

As our barometer had been broken in March 1838, the register of a sympiesometer will be given in describing the gale of June in that year; but as this instrument had been found (by comparison with the barometer) to act exceedingly well, it will be sufficient for our purpose; the GENERAL use of a marine barometer being merely that of a weather gla.s.s, for which purpose a sympiesometer is equally good, and more sensitive.

For the gale of 1840, the register of a barometer is shown, which, although 0.2 too low, will serve to show the effect upon the mercury.

At Swan River, on the 24th of May, 1838, the wind was strong and squally from North-East by North; sympiesometer standing at 30.74. During the day the oil commenced to fall, and continued falling slowly until the 30th, when it was 30.16; during the greater part of this interval, the winds were light, generally from some eastern point in the morning, and going round the compa.s.s, by north and west, during the day; the nights were mostly calm, a heavy bank of clouds was collecting between North-North-East and South-West and the whole western horizon had a gloomy appearance. On the evening of the 30th, the water had risen considerably at the anchorage, and the stream ran to the southward; a fresh breeze also set in from North-East and gradually veered to the northward, as it increased in strength. On the 31st it blew hard all day, between North-North-East and North-North-West, with dark squally weather, much lightning in South-West and heavy rain, that continued all night. On June the 1st, the gale was at its height, and at 8 A.M. (the sympiesometer having fallen to 29.93) was blowing a hard gale, with heavy squalls and rain, from North-West; towards noon the wind veered to west, but still blew very hard; the sympiesometer now began to rise, and in the evening the wind was West-South-West and had moderated considerably, the weather was also clearer, although heavy clouds still hung on the western horizon.

The next morning (the 2nd) the sympiesometer had risen to 30.26; but this was much too sudden a rise (0.33 in 24 hours) to allow us to suppose, that the favourable change in the weather was to be of long continuance; during the day the oil began to fall again, and the wind veered to West and North-West and on the 3rd blew harder than ever, with heavy rain, thunder, and lightning; and, with the exception of occasional intervals, when the wind moderated, this weather continued until the 10th. The wind during this time was variable, between North-North-West and West-South-West, the sympiesometer between 29.81 and 30.16--falling with the North-West winds, and rising as the wind veered to west and West-South-West.

This gale, which may be said to have been of ten days' continuance, caused a very heavy sea upon the coast; the oldest residents at Swan River said they had never experienced so heavy a sea before. On the 10th the gla.s.s commenced to rise steadily, and the weather was fine, with light variable winds, until the Beagle sailed (on the 20th).

Owing to the security of Owen's anchorage, and the good quality of the bottom, the Beagle rode out this bad weather, without causing the slightest apprehension to anyone on board; but had a merchant vessel been in Gage Road, in all probability, she would have added one more to the list of wrecks, that have already done too much in prejudicing strangers against the Swan River settlement.

The gale of May, 1840, at Houtman's Abrolhos, commenced in a similar manner with that already described, but being in a lower lat.i.tude, was of shorter duration, and the indications did not precede it such a length of time; still they were in every respect similar.

This gale commenced on the 2nd of May, in the evening, and lasted until the evening of the 4th.

on April the 29th, the barometer stood at 30.17 (having been some days steadily high); it then commenced to fall, and on the evening of May the 2nd, was 29.86; during this interval we daily experienced strong East-North-East and North-East winds; they generally commenced after midnight, and lasted until noon; a bank of clouds was also collecting in the North-West and there was occasional lightning in that quarter; the early part of May the 2nd was nearly calm, and there was a heavy bank of clouds between North and South-West. After noon a light breeze sprang up from North-West which gradually freshened; and during the night the barometer fell 17-hundredths.

At sunrise on May the 3rd, there was a fresh breeze from North-North-West and the weather had a very dull and gloomy appearance, the wind increasing rapidly, and by noon it blew a heavy gale at West-North-West; the barometer had fallen to 29.58, at which it continued until midnight, when the wind drew to the southward of west, and the mercury began to rise. The gale continued unabated, with squalls and rain, until noon of the 4th, although the barometer had been rising since the previous midnight; in the afternoon the wind moderated, and the weather became fine.

From this it would appear that the barometer gives ample warning of an approaching North-West gale, as it had been falling nearly four days before the commencement of the bad weather, this alone ought to be sufficient to put a man upon his guard if near the sh.o.r.e. Between April the 29th (the first day of the fresh north-easterly winds) and May the 3rd (when the gale was at its height, and the wind began to draw to the southward of west) the mercury had fallen 6-tenths. The change of current did not precede the wind, but changed with it; when the gale was strong from North-West and West-North-West the current ran a knot an hour to the South-East, and when the wind changed to South-West it ran with the same velocity to the North-East.

The west coast of New Holland is at times visited by sudden squalls, resembling hurricanes. I was told by the master of an American whaler, that in March 1839, when in company with several whalers off Sharks' Bay, he experienced some very bad weather, which came on suddenly, without having given any previous warning, but it was not of long continuance; the gusts of wind were very violent, s.h.i.+fting suddenly to all points of the compa.s.s. Some of the s.h.i.+ps suffered considerable damage, in loss of topmasts, etc. others in sails, but all more or less. I think the first squall was from North-East off the land.

The American whalers that resort to the west coast of Australia, are upon different parts of it at all seasons of the year; their range is between the parallel of 10 and 50 degrees of south lat.i.tude. In the summer they fish to the southward, and at that season visit Swan River and King George's Sound, for refreshments; but during the winter months they are rarely to the southward of Sharks' Bay; numbers are to be met off the North-West Cape.

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 lat.i.tude, 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 lat.i.tude.

Between Clarence Straits and Cambridge Gulf, and during the months of September, October, November, and December, the wind during the day is a seabreeze between North-West and West. In September, and until the middle of October, we found the wind as follows: About sunrise, a light breeze sprang up from South-East or East which gradually drew to the northward towards the middle of the day, in the afternoon, a seabreeze from North-West or west, becoming light towards sunset, but freshening again soon after that, and blowing a moderate and pleasant breeze between North-West and South-West all night.

During the latter part of the period (November and December) the winds were more constantly from the West or West-North-West, blowing from that quarter throughout the twenty-four hours, but much more moderate at night than during the day; at full and change of the moon, the breezes were much stronger than at other times, and upon one or two occasions, at the time of the moon's quartering, there was a light breeze from South-East in the morning.

During the month of November, the s.h.i.+p was at anchor, twelve miles within the entrance to Victoria River, and sixty-five from Point Pearce, on the sea coast. For the first three weeks of this time, the seabreeze was regular from North-West or West-North-West, generally setting in about noon, and lasting the greater part of the night; in the mornings, and until noon, it was mostly calm, or very light winds from the northward.

In the last week of this month the weather was very unsettled and squally, with much thunder and lightning, and rain, the wind mostly between South-East and North-East; after which, the westerly breezes set in again, and continued until we left the coast in the middle of December.

During the whole of this period the westerly winds did not appear to come from any distance, but to be merely local seabreezes, as they did not cause any sea upon the coast, nor did they reach far in sh.o.r.e; as we frequently observed smoke at no great distance from the coast, rising perpendicularly, or influenced by a light south-easterly wind, and this at times when the seabreeze was strong. From this it would appear, that the westerly monsoon had not reached so far to the southward, nor did we find, after sailing from Point Pearce, that the winds were at all steady from the westward, until we had reached to the northward of Cape Londonderry, which is in lat.i.tude 13 degrees 45 minutes South. To the northward of this, the winds were from the westward, accompanied by fine weather during the day to the southward of that point--sometimes as far as South-West--and at night inclining to the northward of west, but generally speaking, we found the wind to the southward of west, and the current running from half a mile to a mile an hour to the North or North-North-East.

The currents between New Holland and Timor, are said to run to the westward, during the easterly monsoon--and in the opposite direction with the westerly; but they seem to be influenced by every trifling change of wind--as on the 20th, 21st, 22nd, and 23rd of December (when the westerly monsoon might be supposed at its height) we experienced light, variable winds, between South-East and East-North-East--during which period the current ran to the westward--at times, a knot an hour. We were then between the parallels of 11 1/2 and 13 degrees, south of which we experienced winds between South-South-West and West until we were to the southward of the North-West Cape, when they became more southerly, and at times South-South-East (in January). Throughout all this period, the weather was fine, and different from what was expected during the westerly monsoon.

All that part of the North-West coast of New Holland, between the North-West Cape, and Cape Londonderry, appears to be very much subjected to light winds, particularly during the easterly monsoon, the strength of which is not felt to the southward of 13 or 14 degrees of south lat.i.tude.

During the westerly monsoon, strong winds and gales from the North-West at times blow upon the coast, but they do not appear to be frequent. The strongest winds at this season, are the heavy squalls between East-South-East and North-East (and which may with propriety be termed hurricane squalls); fortunately they are not of long duration, rarely lasting over two hours. They give ample warning of their approach, by the gathering of a heavy bank of clouds between North-East and South-East, and much lightning in that quarter. Appearances such as these frequently precede the squall some days, but coming gradually nearer (to the westward). The barometer shows no indication of approaching bad weather, being only acted upon by the immediate change; these squalls mostly occur in the night, or between sunset and sunrise.

During the latter part of the westerly monsoon, on that part of the coast between Cape Villaret and Point Swan, we found the weather remarkably fine, with the exception of an occasional short, but severe squall, from the eastward. During the day there was generally a moderate seabreeze between North-West and South-West commencing in the forenoon, and lasting sometimes nearly until midnight--on which occasions it blew strongest during the night); during the other part of the twenty-four hours the wind was light from the eastward or calm. Captain King experienced similar weather in August.

It was not until we had reached Point Swan, in lat.i.tude 16 degrees 20 minutes South that we experienced any of the bad weather that is usually met with, at this season of the year, a few degrees to the northward; it commenced in the last week of January, and continued until the middle of February, during which period, there were some strong gales from the westward, between North-West and South-West accompanied by heavy rain, thunder and lightning; but although there was a good deal of dirty weather, it was by no means constant, as there were occasional intervals of fine weather, with moderate westerly winds. This was the only bad weather on this part of the coast, during the season, that could be said to be caused by the westerly monsoon, if we except the East-South-East squalls, that do not occur in the easterly monsoon.

While this weather lasted, the easterly squalls were quite suspended, and the heavy bank of clouds that had generally been noticed in the South-East had dispersed for the time; but after the strong westerly winds had ceased, the weather was generally fine, and the wind mostly from some western point; there were occasional showers, and the clouds in the eastern horizon resumed their threatening appearance, bringing some hard squalls, and rain from that quarter. In the middle of March (being the time when equinoctial gales are looked for in most parts of the world) there were two or three days of squally, unsettled weather, with rain, that seemed to terminate the season of the westerly monsoon. After the 1st of April, the weather was invariably fine, and the easterly squalls had ceased to trouble us; land and seabreezes became regular, and the easterly monsoon had no doubt set in to the northward; the strongest breezes now were from South-East but, generally speaking, the winds were very light near the land.

It does not appear that the westerly monsoon blows with any degree of regularity, to the southward of the 13th degree of south lat.i.tude; although for some degrees south of that, the weather is influenced by it, and winds between West-North-West and South-West will be experienced, and from the appearances on many parts of the coast, there are no doubt strong gales at times from the westward, that send in a very heavy sea.

During the easterly monsoon, the weather is fine on the North-West coast, particularly in the months of May, June, July, and August; this is undoubtedly the best time for visiting it; land and seabreezes are regular, and the temperature is very agreeable.

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 s.h.i.+p, 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.