A Voyage to Terra Australis Volume II Part 6

The _lat.i.tude_ of Pier Head, from an observation made at the top in an artificial horizon, is 22 6' 53" S.

_Longitude_ from thirteen sets of distances of the sun west of the moon, observed by lieutenant Flinders, 149 47' 50"; but by the survey and the fixed position in Broad Sound, with which the time-keepers agreed, it will be more correctly 150 0' 10" E.

Captain Cook specifies the situation of Thirsty Sound to be in lat.i.tude 22 10', longitude 149 42' (Hawkesworth, III, 128); but in the chart published by Mr. Dalrymple, it is 22 7' and 149 36', which agrees nearer with the deductions of Mr. Wales (_Astron. Obs._ p. 135). In either case it appears, that my longitude was getting more eastward from captain Cook as we advanced further along the coast.

WEDNESDAY 8 SEPTEMBER 1802

The tides in Thirsty Sound were neaped at this time, and the rise, judging by the lead line, was from ten to twelve feet; but captain Cook says, "at spring tides the water does not rise less than sixteen or eighteen feet," which I have no doubt is correct. It ceases at _ten hours and three quarters after_ the moon pa.s.ses over and under the meridian.

On quitting Thirsty Sound we steered north-westward, to pa.s.s round a chain of rocks extending six miles out from Pier Head, and behind which there was a bight in Long Island, with some appearance of an opening. It was my intention to examine Broad Sound up to the furthest navigable part, and we hauled up between the north point of Long Island and a cl.u.s.ter of small isles lying three miles to the north-west; but finding the water too shallow, and that it would be more advantageous to begin the examination on the west side, I desired Mr. Murray to lead round the _North-point Isles_ and across the sound. A small reef lies between four and five miles N. E. by E. from the largest and easternmost of these isles; it is covered at half tide, and therefore dangerous, but we had 7 to 8 fathoms at less than a mile distance, on the inside.

At noon, the depth was 8 fathoms, the largest North-point Isle, which is nearly separated into two, was distant four miles, and our situation was as under:

Lat.i.tude observed to the north, 21 56' 17"

Pier Head top, bore S. 38 E.

Northumberland Island, peak marked 'h', N. 15 W.

North-point I., westernmost, highest part, S. 56 W.

North-point I., largest, S. 37 to 16 W.

In steering W. by N., rippling water was seen ahead at one o'clock. and the depth diminis.h.i.+ng to 4 fathoms, we hauled a little to the southward and then resumed our course. This rippling seems to have been on a part of the same shoal near which captain Cook anch.o.r.ed in 3 fathoms; for it lies five miles from the North-point Isles, and as he says, "half way between them and three small islands which lie directly without them."

[EAST COAST. BROAD SOUND.]

Our course for the west side of Broad Sound pa.s.sed close to some low, flat isles, lying to the south-east of the peaked West Hill set from Pier Head. At dusk I sought to anchor behind the hill, for it had the appearance of being separated from the main land; but the water being too shallow, we hauled off upon a wind. At ten o'clock, however, the breeze having become light and the sea gone down, an anchor was dropped in 5 fathoms, sandy bottom; whence the top of West Hill bore N. 68 W. three miles. A flood tide was found running from the N. N. E., one mile and a quarter per hour.

THURSDAY 9 SEPTEMBER 1802

In the morning I landed with the botanical gentlemen, and wished to ascend the top of the hill; but the brush wood was too thick to be penetrable. Upon a projecting head on the north-east side, I took a part, and about half way up the hill on the south-east side, the remainder of a set of bearings, which included many of the Northumberland Isles not before seen, and other of the Flat Isles within Broad Sound. The furthest visible part of the main land towards Cape Palmerston, was distant about five leagues, and behind it was a hill to which, from its form, I gave the name of _Mount Funnel_; the sh.o.r.e both to the north and south was low, and the Flat Isles to the southward of the s.h.i.+p were mostly over-run with mangroves. I did not go round West Hill, and could not see whether it were connected with the main land, or not; but if joined, it must be by a very low isthmus. The bearings at this station, most essential to the connection of the survey, were these:

Main coast, the extremes, N. 1 and S. 10 45'

E.

Pier Head, the top, S. 61 25 E.

Northumberland Isles, peak marked 'h', N. 61 45 E.

Northumberland Isles, high northmost marked 'i', dist. 11 L. N. 19 15 E.

The stone of the hill had in it specks of quartz or feldtspath, and was not much unlike that of Pier Head; but it had a more basaltic appearance.

A piece of it applied to the theodolite, drew the needle two degrees out of its direction, and yet the bearings did not show any great difference from the true variation; for an amplitude taken on board the s.h.i.+p by Mr.

Flinders, when the head was N. N. E, gave 6 18', or corrected to the meridian, 7 17' east, and the variation on the eastern side of the hill was 8 15', according to the back bearing of Pier Head.

From an observation of the sun's upper and lower limbs in an artificial horizon, the lat.i.tude was 21 50' 18", and the s.h.i.+p bore from thence S.

68 E. two miles and a half; the lat.i.tude of the s.h.i.+p should therefore have been 21 51' 14"; but a meridian alt.i.tude observed to the north by lieutenant Flinders, gave 21 49' 54"; and I believe that alt.i.tudes from the sea horizon can never be depended on nearer than to one minute, on account of the variability of the horizontal refraction. From this cause it was that, when possible, we commonly observed the lat.i.tude on board the s.h.i.+p both to the north and south, taking the sun's alt.i.tude one way and his supplement the other, and the mean of the two results was considered to be true; separately, they often differed 1', 2', and even 3', and sometimes they agreed. The observation to the north most commonly gave the least south lat.i.tude, but not always, nor was there any regular coincidence between the results and the heights of the barometer or thermometer; though in general, the more hazy the weather, the greater were the differences. At this time, the wind was light from the eastward and weather hazy; the thermometer stood at 72, and barometer at 30.15 inches.

At two o'clock we got under way to go up Broad Sound, it being then near low water. After steering south-east one mile, the depth rapidly diminished and we tacked; but the s.h.i.+p was set upon a bank of sand, where she hung five minutes and then swung off. I afterwards steered nearer to the sh.o.r.e, in deeper water; and at dusk the anchor was dropped in 5 fathoms, sandy bottom, between the Flat Isles and the main, West Hill bearing N. 35 W. three leagues; the master sounded towards the coast, which was five miles off, and found the deepest water to be on that side.

In the morning [FRIDAY 10 SEPTEMBER 1802] the wind had s.h.i.+fted to south, and we beat up in a channel formed by the Flat Isles and the shoals attached to them, on one side, and the shelving banks from the main coast, on the other. We had the a.s.sistance of a strong flood tide till eleven o'clock; at which time the anchor was let go, one mile from the north end of the 4th Flat Island.

I landed immediately, with the botanists; and at the south-east end of the island, which is a little elevated, took bearings and the meridian alt.i.tude of both limbs of the sun from an artificial horizon. The lat.i.tude deduced was 22 8' 33"; and the s.h.i.+p bearing N. 19 30' W., two miles, it should have been for her, 22 6' 40"; but lieutenant Flinders'

observation to the north gave 22 5' 19", or 1' 21" less, nearly as on the preceding day; and it was ascertained that the difference arose neither from the eye nor the instrument. Amongst the bearings were,

West Hill, the top, N. 16 40' W.

Northumberland Isles. the peak marked 'h', N. 25 15 E.

Long Island, extreme of the north point, N. 73 35 E.

Upper Head, on the west sh.o.r.e up Broad Sound, S. 39 55 E.

The 4th Flat Isle is about one mile long, and there is a smaller lying off its south-east end; they are a little elevated, and bear gra.s.s and small trees; but the sh.o.r.es are covered with mangroves, and surrounded with extensive flats of mud and sand. The main coast, from which they lie two or three miles, is also low, with mangroves and shelving mud banks; but there is a deep channel between, of a mile in width. In the evening, when the flood made, we steered into this channel with a light sea-breeze; but not having time to clear it before dark, the anchor was dropped in 4 fathoms at six o'clock.

My attention was attracted this evening by the vast extent of mud left dry on each side of the channel, and I ordered particular attention to be paid to the tides during the night. At eleven o'clock, when the flood had ceased running, the depth was sounded and the lead line measured, and the same at half past five in the morning [SAt.u.r.dAY 11 SEPTEMBER 1802] when it was low water; the difference was no less than thirty-two feet, and it wanted a day of being full moon; so that the springs may reach two or three feet higher. The flood set S. by E., but its greatest rate did not exceed one mile and three quarters an hour.

At daylight the wind was south-east, directly against us. We backed and filled, drifting up with the flood between the shoals on each side, and having the Lady Nelson and a boat ahead; but on approaching the end of the channel, our pa.s.sage into the sound was blocked up by a bank running across, upon which there was not water enough for the s.h.i.+p by a fathom, and we therefore anch.o.r.ed. At nine the tide had risen a fathom. and we pa.s.sed over into the open sound; the depth immediately increasing to 4 and 7 fathoms, reduced to low water. So long as the flood continued running we worked up the sound; and when it ceased, anch.o.r.ed three miles from a shallow opening in the low western sh.o.r.e, the second which had been observed. We again proceeded upwards with the evening's tide until dusk; and at nine next morning [SUNDAY 12 SEPTEMBER 1802] pa.s.sed a fifth opening, and anch.o.r.ed abreast of the hilly projection on its east side, which I have named _Upper Head_, in 4 fathoms, soft bottom, two-thirds of a mile from the sh.o.r.e. This was the first place on the main where there was any prospect of being able to land; for the western sh.o.r.e, thus far up, was equally low, and as much over-run with mangroves and defended by muddy flats, as the sh.o.r.es of Keppel Bay.

It being my intention to explore the head of Broad Sound with the brig and whale boat, a situation where tents could be fixed and an easy communication held with the s.h.i.+p during my absence, was the object now sought; and I immediately went with a party of the gentlemen, to ascertain how far Upper Head was calculated for our purpose. We landed at half flood, without difficulty; and on ascending the hill, obtained a view of the Sound which exceeded my expectations. Amongst the many bearings taken, were the following fixed points in the survey.

Pine Mount, of Shoal-water Bay, S. 84 38' E.

Pier Head, the western part, N. 36 7 E.

West hill, the top, N. 28 5 W.

Flat Isles, the 4th, station there, N. 39 53 W.

The breadth of the Sound, from Upper Head over to the inner end of Long Island, appeared to be three leagues, but it contracted upwards, and a.s.sumed the same river-like form as Shoalwater Bay; and it was to be feared, from the mangrove sh.o.r.es and muddiness of the water, that it would terminate in the same manner. No shoals could be then distinguished; but towards low water in the evening I again ascended the hill, and saw to my regret, that the upper parts were mostly occupied with banks of mud and sand, many of which were dry, and extended downward past the inner entrance of Thirsty Sound. Amongst the banks were various channels; but that of about two miles wide where the s.h.i.+p lay, was by far the most considerable. The small fifth opening, close on the west side of Upper Head, ran some miles in the low land towards the foot of a ridge of hills, lying three or four leagues at the back of the sh.o.r.e; but the greater part of this inlet was also taken up by mud banks, and the borders covered with mangroves. There was no fresh water at Upper Head, nor did I see any prospect of obtaining wherewith to complete the holds of the two vessels before leaving the coast; unless it were at a place a little higher up on the same side, to which the appearance of another opening between two hills, induced me to move the s.h.i.+p.

MONDAY 13 SEPTEMBER 1802

Next morning, when the flood made, we drifted upwards, with the Lady Nelson and a boat sounding ahead. After advancing three miles the brig suddenly took the ground, and we dropped a stream anchor; but in swinging to it, the s.h.i.+p was caught upon a bank of quick sand in eleven feet; and the tide running strong upon the broad side, it made her heel in a manner to excite alarm. The sails were immediately clewed down, and the top-gallant yards struck; and it appearing that the stream anchor allowed the s.h.i.+p to drive further up the bank as the tide rose, the best bower was let go, and then she righted and swung to the tide. The Lady Nelson also got off safe; but a part of the after sliding keel was carried away.

I went in a boat to examine the place which had presented the appearance of an opening; but it proved to be only a bending in the sh.o.r.e, and the mud banks and mangroves did not admit of landing; we therefore went back with the returning ebb to Upper Head, and moored the s.h.i.+p nearly in our first situation; where there was something more than 3 fathoms all round, at low water.

TUESDAY 14 SEPTEMBER 1802

On the following morning, the time keepers and other instruments were sent on sh.o.r.e under the charge of lieutenant Flinders, with two of the young gentlemen to a.s.sist him, and a guard of marines for the protection of the tents. It had appeared from the survey, that the time keepers were losing more than the Port-Jackson rates supposed; and before quitting this coast for the Gulph of Carpentaria, it was necessary to take fresh observations. Mr. Flinders undertook as usual to perform this service, whilst I should be absent up the Sound; and lieutenant Fowler was directed to examine and air all the stores, and make the s.h.i.+p ready for sea against my return.

Having made these dispositions, I embarked in the Lady Nelson with the naturalist, taking my whale boat and surveying instruments. We had a strong flood tide; and after grounding on a bank, anch.o.r.ed eleven miles above the s.h.i.+p, in 3 fathoms, that being the greatest depth to be found.

It was then high water; and the brig being expected to be left dry by the ebb, we prepared for it by mooring, to prevent all chance of settling on the anchor, and hove up the fore and after keels; the new main keel being swelled by the wet, could not be raised, and when it took the ground, the vessel turned about violently and dragged both the anchors, until the keel broke off, and then she lay easy.

At low water, the seamen went out upon the dry flat and found the best bower cable parted, and the anchor so far buried in the quicksand, that it could not be raised. At ten o'clock the flood tide came rolling in, and presently set the brig afloat; the anchor was then weighed with ease, by means of a hawser previously bent to it, and the vessel rode by the small bower, against a tide which ran at the strongest between four and five knots.

WEDNESDAY 15 SEPTEMBER 1802

The Lady Nelson again took the ground at six in the morning. On sounding over to the east sh.o.r.e, distant half a mile, I found a small channel leading upwards, with four or five feet more water in it than where the brig lay; the western sh.o.r.e was two miles distant over a silty flat, which was dry at low water and level as a race ground.

At eleven, the flood came in, six or eight inches perpendicular, with a roaring noise; and so soon as it had pa.s.sed the brig, I set off with Mr.

Brown and Mr. Lacy in the whale boat, to follow it up the small channel on the eastern sh.o.r.e; and having a fair wind we outran the tide and were sometimes obliged to wait its rising before we could proceed. At the end of six miles the small channel led across to the western side; and the rare opportunity of a landing place induced me to pitch our tent there for the night: two miles higher up, the whole breadth of the Sound was reduced to half a mile.

The country here was a stiff, clayey flat, covered with gra.s.s, and seemed to have been overflowed at spring tides; though the high water of this day did not reach it by five feet. Three or four miles to the southward there were some hills, whence I hoped to see the course of the stream up to its termination; and having time before dark, we set off. The gra.s.s of the plain was interspersed with a species of sensitive plant, whose leaves curled up in, and about our footsteps in such a manner, that the way we had come was for some time distinguishable. From the nearest of the small hills, I set the bearings of Double and Pine Mounts, our tent, and the brig at anchor, by which this station was fixed as in the chart; but in order to reconcile the bearings, I found it necessary to allow 12 of east variation.