than a mile distant. It is of a circular form, nearly 8 miles in circumference, and its summit is 514 feet above the sea.

This island is merely a vast pile of large blocks of greenstone, heaped up in rugged and irregular masses: it has much the appearance of basalt, and in many places the long, flat-sided blocks resemble columns of that formation. Here and there in the valleys, and upon the more level spaces near the summit, is a slight sprinkling of soil that nourishes a few stunted gum-trees, shrubs, and a coarse wiry grass; but, generally speaking, the island is void of vegetation, and has altogether a very different appearance from the mainland and the other islands of Forester's group, of which it is the largest.

With the exception of Depuch Island, the other islands of this group are very low; each being merely an accumulation of sand, upon a base of light-coloured rock, that is composed chiefly of sand and shells. They are in some places thickly covered with brushwood and coarse grass, and their greatest elevation is not more than 50 feet.

All these islands are connected to the mainland by extensive flats and ridges of sand, which in many places become quite dry at lowwater spring-tides, and afford great facility to the natives in reaching them for the purpose of procuring turtle and fish. Indeed, as nothing was seen to lead us to suppose that canoes are used on that part of the coast, it appears more than probable that it is only at such periods they are able to visit them.

Depuch Island appears to be their principal resort, probably on account of the water they find amongst the rocks after rainy weather, and the facilities afforded them in the exercise of their talent for drawing representations of whatever they have seen upon the flat surface of the rocks of which that island is formed.

From the vast number of specimens of the art, the natives seem to have amused themselves in this way from time immemorial; and from the very hard nature of the stone, and the accuracy with which many animals and birds are represented, they deserve great credit for patient perseverance, and for more talent and observation than is usually bestowed upon the natives of New Holland; and to their greater credit be it told, that, amongst the numerous representations we saw, none were observed to tend in the slightest degree towards obscenity.

The method pursued in tracing the different subjects appears to be by cutting the surface of the rock with sharp pointed pieces of the same stone; and as the exterior of all parts of it is of a dark reddish brown colour, the contrast becomes great when that is removed and the natural colour of the greenstone exposed. It is difficult to conjecture what many of their drawings are intended to represent, but others are too well done to admit of a moment's doubt. Probably many of the inferior performances were the work of the children.

From the summit of the island we had a good view of the mainland for several miles from the sea; and, with the exception of a few isolated rocky hills of the same greenstone, or basaltic formation, that are six or seven miles from the shore, it appeared to be very low and level. Many places had a very white appearance, as if covered with a salt incrustation, and the whole was intersected by creeks that extended a long distance in, and probably flood a great part of this extensive flat,

when spring-tides are accompanied by the strong north-westerly winds. that are at times felt upon this part of the coast during the prevalence of the westerly monsoon.

While the Beagle remained at Depuch Island no opportunity offered of communicating with the natives, nor did they visit the island during that period. They were seen on the shore of the mainland upon one or two occasions; but as soon as any attempt was made to approach them in the boats they fled precipitately. Like most of the natives of that country who have never seen Europeans, they are timid, and probably treacherous, when their numbers exceed those of the opposite party. The following trifling circumstance justifies this apparently harsh suspicion. Mr. Fitzmaurice (Mate), while employed in a whaleboat in surveying a part of the coast a little to the eastward of Depuch Island, entered a creek for the purpose of ascertaining its extent, but had not proceeded far before his progress was stopped by the near approach of the mud-banks, rendering it too narrow for the oars. He was not long in this position before he was startled by a loud shout, and the appearance of a party of natives rushing simultaneously from the mangroves on each side of the creek: they stopped at a short distance from the boat and made threatening gestures, by brandishing their spears. No doubt violence would have ensued had he persisted in his attempt to proceed farther into the creek, but he very properly backed his boat out, and retreated; it being, perhaps, better, when practicable, to allow the natives to imagine themselves the stronger party than to teach them experience upon such a subject by the use of fire-arms, which must have been resorted to had spears been thrown.

This is a very good and well sheltered anchorage off the sandy beach on the N.E. side of Depuch Island; but with this exception, it offers no inducement to visit it again. A trifling supply of fire-wood may be procured from the stunted trees that grow in some of the valleys; but water is not to be depended upon at all seasons of the year, although there were evident marks of a very bountiful supply during the rains. We dug wells wherever a level spot held out any prospect of success, but our labours were generally obstructed by reaching a bed of white calcareous rock, from 9 to 15 feet below the surface. With one well in the sandhills at the N.E. bay we succeeded in reaching to the depth of 21 feet, where we found a bed of sand-stone, sufficiently soft to yield to the united effects of pickaxes and crowbars: the laborious work of cutting through this was carried on a few feet farther, when our exertions were stopped by a stream of water flowing in as salt as the ocean. Fortunately a small reservoir was discovered by Mr. Bynoe, the surgeon, while climbing amongst the rocks in search of a fresh meal, from which we got about 6 tons of indifferent rain-water, but at the expense of very harassing labour, as it was carried on the men's shoulders, in 7-gallon barricoes, over the most rugged path one can well imagine. This supply enabled us to remain a few days longer on the coast, when we were compelled to cross over to Timor, for what was not to be procured on the inhospitable and sandy shores of N.W. Australia.

ON THE TIDES of the IndiaN ARCHIPELAGO.

DURING the year 1839, a correct observation of the tides took place in several parts of these (the Dutch Indian) colonies, as at Palo Chinco, on the west coast of Sumatra, Minto, in the Straits of Banca, Amboyna, in the Moluccas, Macassar, on the island of Celebes, Klampis, on the north coast of Madura, Tagal, on the north coast of Java, Karimon Java, a group of islands in the Java Sea, Onrust Island, near Batavia, and at Chalachap, on the south coast of Java.

In comparing the results of the observations on the tides made at the places above mentioned, a remarkable difference will be observed between those taken outside the Archipelago, as on the west coast of Sumatra, south coast of Java, and also at Amboyna, and those taken within the Java Sea.

It appears that, at the former places the generally known rules of the tides are followed; high and low water occurring twice in twenty-four hours, there being two tides within this period, while at the same time they are influenced by the age of the moon. A table can, therefore, be given, by which the variations of the tide can be reckoned with correctness before hand. This is by no means the case with places within the Java Sea, where the tides cannot be tested by the same rules, appearing to depart chiefly on the locality of the solstice, and in the state of the monsoons in connection with it.

It may be premised that, throughout the Java Sea there is high water only once in the twenty-four hours, and that besides these long tides, (or rather rising and falling of the water, which together occupy rather more than twenty-four hours,) small or short tides take place, whose tolerably well regulated return appears to be dependent on various causes, but, more especially on the solstice, or on the prevailing monsoon. These short tides may also, probably be brought under fixed rules since the natives seem to be well acquainted with their motions. At the periods of new and full moon, high water generally occurs at a certain fixed time, but the intervening tides are so irregular that a correct tide table cannot be formed.

The general yearly retrogradation of the daily period of high and low water, which also appears to depend on the solstice, is like the short or middle tides, peculiar to the Java Sea, or probably to all inlets and seas enclosed by an archipelago; and it is farther to be remarked that the currents in this sea are even more irregular than the rising and falling of the tides, these appearing to be influenced chiefly by the prevailing winds.

To commence with the places at which the tides follow the general rules:

*

1st. At Palo Chinco, on the west coast of Sumatra, high water occurs at full and change at 5h. 30m. The mean rise and fall is 0.78 ells, the highest and lowest being 1.49 and 0.06 ells. It may further be stated that the stream of flood comes from the south-east, following the line of the coast, the ebb running in an opposite direction. Both

The Netherland ell is rather more than the English yard,-1 Netherland ell being 1.094 English yard.

are weak, seldom running more than a mile in the for hours, and they are considerably influenced by the prevailing winds.

2nd. At Chalachap, on the south coast of Java, the time of high water at full and change is 8h. 30m.; mean rise and fall 1.25 ells; greatest and least rising and falling 2.42 and 0.10. In the channel on which this place is situated, the direction of the flood tide is to the west, and the ebb to the east, following the direction of the channel. This is also the case in the western entrance of the channel. The tides meet in Segara Anakan, a bay just within the western entrance, where there is a rising and falling of the tide, but no stream. It appears, however, that along the south coast of Java, at least in the east monsoon, a current sets to the eastward, running at the rate of two miles in the four hours.

3rd. In the bay of Amboyna the time of high-water at full and change is Oh. 30m.; the mean rise and fall is 114 ells; the greatest and smallest rising and falling being 2.50 and 0.00 ells. In this bay the stream of tide is very inconsiderable, there being scarcely any to be perceived in the centre. The flood comes in along the north (northwest) side of the bay, and returns along the south side only, occasionally the stream was found to run eight and ten miles in the four

hours.

Places in which the tides do not follow the general rules.

1st. At Klampis on the north coast of Madura, the current during the east monsoon runs to the west, sometimes, as in the month of May, at the rate of ten to twelve miles in the four hours, this always occurring during the day; while during the night there is scarcely any current observable; what little there is, however, running to the east. The only exception to this occurs in the month of July, when the stream runs to the westward during the night also, at the rate of eight to twelve miles, in the four hours. In this (the east) monsoon, the water falls generally during the day, and the stream is then the strongest, while during the night the water usually rises, there being at this time very little current; from which it would appear that if there are indeed streams of flood and ebb, the former must come from the west, and the latter from the east, the stream of flood being held in abeyance by the prevailing easterly winds. In the west monsoon the stream of flood has a weak set to the eastward, the tide, at this season, rising by day; while the ebb, which should run in an opposite direction has scarcely any force, probably from its being held in abeyance. by the prevailing westerly winds. High and low water each occur only once in the twenty-four hours, although it appears that slight risings and fallings, called small or middle tides, sometimes occur within this period. It may further be stated, that in the east monsoon, high water always occurs before noon, hence the falling of the water, and therefore the ebb occurs during the day. In the west monsoon high water always occurs after the sun has passed the meridian, the ebb, therefore, occurring during the night.

Although no regular tide table can be given, it may be stated as a general rule that, during the east monsoon at full and change, high ENLARGED SERIES-NO. 9.-VOL FOR 1843.

4 F

water occurs between 8h. and 10h. in the morning, and in the west monsoon between 8h. and 10h. in the evening.

At the other places in the Java Sea where the tides have been observed, the result is so similar to that of Klampis, that it is unnecessary to translate this paper any further. On the north coast of Australia, the flood tide also comes from the westward, and at Point Smith, at the entrance of Port Essington, I have noticed the same peculiarity in the tides that has been observed at Klampis, the flood and ebb sometimes, each running nine hours, the tide remaining at its highest and lowest points rather more than three hours.

In the inner harbour, however, we have regular tides, but we have noticed that in the springs the lowest tide always occurs during the night, and the highest during the day.

I subjoin a sketch of the current prevailing in the Molucca, Timor, and Arafura Seas, (the result of the observations I have made during my occasional trips from Port Essington,) which appears to be the same in both monsoons, except that during the westerly monsoon there is a set of nearly two miles an hour to the eastward, between the north-east extreme of Timor and Port Essington, while during the easterly monsoon this set is scarcely perceptible. The current in these seas, which in some parts, the Ombay passage for instance, sets constantly to the south-west, at the rate of from two to five miles per hour, is evidently caused by the body of water driven in from the North Pacific by the eaterly winds which prevail there. May not this current, which must strike the north-west coast of Australia, have some influence in causing the enormous high tides which occur about Buccaneers Archipelago. G. W. E.

ON THE MARINERS' COMPASS:-By Mr. W. Walker, Master R.N. (Continued from p. 522.)

DURING a period of 180 years that the Mariners' Compass had been in use among the Christians of the 14th and 15th centuries, its character had been slowly, but surely established, notwithstanding the intolerant and superstitious spirit of the times. Every thing likely to expand the faculties of the human mind, or, appearing above the comprehension of the vulgar, was represented as profane or abominable, and dealt with accordingly. Men of superior abilities in their pursuits, instead of being patronized, were either actually persecuted, or else, met with no encouragement in advancing the progress of useful knowledge. It was dangerous for men to meddle with doctrines or opinions of any kind, not sanctioned, received, or approved by the clergy, and this intolerant spirit extended to a much later period then I refer to, as witness the persecution of poor Galileo, who was thrown in the dungeons of the inquisition at Rome in the year 1633, for having ventured to assert that the earth was round, and turned daily on its own axis!

It was under such unfavorable circumstances as these that maritime discovery, and the art of navigation and seamanship advanced, guided