In consequence of the elevation of Vacouas, the climate is as much different from that of the low parts of the island as if it were several degrees without the tropic; June, July, and August are the driest months at Port Louis, but here they are most rainy, and the thermometer stands from 7° to 12° lower upon an average throughout the year.* In a west direction, across that part of the Plains of St. Pierre called Le Tamarin, the sea is not more distant than six miles; the descent is therefore rapid, and is rendered more so from three-fourths of the space being flat, low land; in comparison with Le Tamarin, Vacouas is in fact an irregular plain upon the top of the mountains, to which there is almost no other access than by making a circuit of four or five miles round by the lower part of Wilhems Plains. Three rugged peaks called the Trois Mamelles, and another, the Montagne du Rempart, all of them conspicuous at sea, are the highest points of a ridge somewhat elevated above this irregular plain, and bounding it to the westward; and the road forming the ordinary communication between the high and low land passes round them. My retreat, which very appropriately to the circumstances of my situation bore the name of The Refuge, lay two or three miles to the south-east of the Trois Mamelles.
[* The mean height of the thermometer in July 1805, which is the middle of winter, was 67¼°, and of the barometer in French inches and lines, 26.7¾; and during February 1806, the middle of summer. 76° and 26.5¾ were the mean heights. At M. Pitot's house in the town of Port Louis, the averages in the same February were 86° and 27.7¾. According to De Luc, the difference between the logarithms of the two heights of the barometer expresses very nearly the difference of elevation in thousand toises, when the thermometer stands at 70° in both places; and therefore the approximate elevation of Vacouas above M. Pitot's house, should be
187¼ toises, or in French feet, 1123
Correction for excess of thermometers above 70°, + 25
Supposed elevation of M. Pitot's house above the sea, + 40
----
Elevation of Vacouas in French feet, 1188
The English foot being to the French, as 12 is to 12.816, the height of Vacouas above the level of the sea should be nearly 1269 English feet.]
The principal rivers in the neighbourhood are the R. du Tamarin and the R. du Rempart, each branching into two principal arms; these collect all the smaller streams in this portion of the island, and arriving by different routes at the same point, make their junction at the head of the Baye du Tamarin, where their waters are discharged into the sea. In wet weather these rivers run with great force, but in ordinary times they do not contain much water; and their smaller branches are mostly dried up in October and November. Both arms of the R. du Rempart take their rise between one and two miles to the S. by E. of the Refuge, and within half a mile of the Mare aux Vacouas, from which it is thought their sources are derived; the western arm bears the name of R. des Papayas, probably from the number of those trees found on its banks;* and taking its course northward, is the boundary between two series of plantations, until it joins the other branch at the foot of the Montagne du Rempart and its name is lost. The Refuge was one of these plantations bounded by the R. des Papayes, being situate on its eastern bank, and receiving from it an accession of value; for this arm does not dry up in the most unfavourable seasons, neither does it overflow in the hurricanes.
[* The papaye, papaya, or papaw, is a tree well known in the East and West Indies, and is common in Mauritius; the acrid milk of the green fruit, when softened with an equal quantity of honey, is considered to be the best remedy against worms, with which the negroes and young children, who live mostly on vegetable diet, are much troubled.]
The eastern arm bears the name of R. du Rempart throughout, from its source near the mare or lake to its embouchure. Its course is nearly parallel to that of the sister stream, the distance between them varying only from about half a mile to one hundred and twenty yards; and the Refuge, as also the greater number of plantations on the eastern, or right bank of the R. des Papayes, is divided by it into two unequal parts, and bridges are necessary to keep up a communication between them. Although the source of this arm be never dried up, yet much of its water is lost in the passage; and during five or six months of the year that nothing is received from the small branches, greater or less portions of its bed are left dry; there seems, however, to be springs in the bed, for at a distance from where the water disappears a stream is found running lower down, which is also lost and another appears further on. In the summer rains, more especially in the hurricanes, the R. du Rempart receives numberless re-enforcements, and its torrent then becomes impetuous, carrying away the bridges, loose rocks, and every moveable obstruction; its partial inundations do great damage to the coffee trees, which cannot bear the water, and in washing off the best of the vegetable soil. During these times, the communication between those parts of the plantations on different sides of the river is cut off, until the waters have in part subsided; and this occurred thrice in one year and a half.
At the western end of the Mare aux Vacouas is an outlet through which a constant stream flows, and this is the commencement of the principal branch of the R. du Tamarin; the other branch, called the R. des Aigrettes, is said to take its rise near a more distant lake, named the Grand Bassin; and their junction is made about one mile to the S. S. W. of the Refuge, near the boundary ridge of the high land, through which they have made a deep cut, and formed a valley of a very romantic character. A short distance above their junction, each branch takes a leap downward of about seventy feet; and when united, they do not run above a quarter of a mile northward before they descend with redoubled force a precipice of nearly one hundred and twenty feet; there are then one or two small cascades, and in a short distance another of eighty or a hundred feet; and from thence to the bottom of the valley, the descent is made by smaller cascades and numberless rapids. After the united stream has run about half a mile northward, and in that space descended near a thousand feet from the level of Vacouas, the river turns west; and passing through the deep cut or chasm in the boundary ridge, enters the plain of Le Tamarin and winds in a serpentine course to the sea.
The R. du Tamarin is at no time a trifling stream, and in rainy weather the quantity of water thrown down the cascades is considerable; by a calculation from the estimated width, depth, and rate of the current after a hurricane, the water then precipitated was 1500 tons in a minute. There are some points on the high land whence most of the cascades may be seen at one view, about a mile distant; from a nearer point some of them are perceived to the left, the Trois Mamelles tower over the woods to the right, and almost perpendicularly under foot is the impetuous stream of the river, driving its way amongst the rocks and woods at the bottom of the valley. In front is the steep gap, through which the river rushes to the low land of Le Tamarin; and there the eye quits it to survey the sugar plantations, the alleys of tamarinds and mangoes, the villages of huts, and all the party-coloured vegetation with which that district is adorned; but soon it passes on to the Baye du Tamarin, to the breakers on the coral reefs which skirt the shore, and to the sea expanded out to a very distant horizon. An elevation of ten or eleven hundred feet, and the distance of three or four miles which a spectator is placed from the plantations, gives a part of this view all the softness of a well-finished drawing; and when the sun sets in front of the gap, and vessels are seen passing before it along the coast, nothing seems wanting to complete this charming and romantic prospect.
Amongst the natural curiosities of Mauritius may be reckoned the Mare aux Vacouas, situate about two miles S. by E. of the Refuge. It is an irregular piece of fresh water of about one mile in length, surrounded with many hundred acres of swampy land, through which run four or five little streams from the back hills; in some places it is from 20 to 25 fathoms deep, as reported, and is well stocked with eels, prawns and a small red fish called dame-ceré, originally brought from China. The eels and prawns are indigenous, and reach to a large size; the latter are sometimes found of six inches long without the beard, and the eels commonly offered for sale ran from six to twenty, and some were said to attain the enormous weight of eighty pounds. This fish is delicate eating, and the largest are accounted the best; its form has more affinity to the conger than to our fresh-water eel, and much resembles, if it be not exactly the same species caught in the small streams of Norfolk Island in the Pacific Ocean. Whence it is that fresh-water fish should be found on small islands, frequently at several hundred leagues from other land, will probably long remain one of the secrets of nature; if it were granted that they might come by sea, the difficulty would scarcely be less to know how they should have mounted precipices of many hundred feet, to reach lakes at the tops of mountains where they are not uncommonly seen.
Five or six miles to the south of the Refuge lies another lake of fresh water, called the Grand Bassin; its situation is more elevated than Vacouas, and except the ridges and tops of mountains, it seemed to be in the highest part of the island. This basin is nearly half a mile in diameter, of a form not far from circular, and is certainly deep; but that it should be 84 fathoms as was said, is scarcely credible. The banks are rocky, and appear like a mound thrown up to keep the water from overflowing; and the surrounding land, particularly to the south, being lower than the surface of the water, gives the Grand Bassin an appearance of a cauldron three-quarters full. No perceptible stream runs into it, but several go out, draining through hollow parts of the rocky bank, and forming the commencement of so many rivers; the Rivières des Anguilles, Dragon, and du Poste fall into the sea on the south or south-east parts of the island; the R. des Aigrettes before mentioned, and the R. Noire which runs westward, rise not far off, but their asserted subterraneous communication with the basin is doubtful. No great difference takes place in the level of the water except after heavy rains; when the supply, which must principally come from springs in the bottom, so far exceeds the quantity thrown out, as to raise it sometimes as much as six feet.
On the western bank is a peaked hill, from which the Grand Bassin is not only seen to much advantage, but the view extends over great part of Mauritius, and in several places to the horizon of the sea. It was apparent from hence, that between the mountains behind Port Louis and those of La Savanne to the south, and from the R. Noire eastward to Port Bourbon, not one-half, probably not a third part of the primitive woods were cut down; and this space comprehends three-fifths of the island, but excludes great part of the shores, near which the plantations are most numerous.