springs which descend from the neighbouring mountains of a greater height often indicate a too rapid decrement of heat. If indeed we suppose the mean temperature of the water on the coast of Cumana equal to 26°, we must conclude, unless other local causes modify the temperature of the springs, that the spring of Quetepe acquires it's great coolness at more than 350 toises of absolute elevation *. In speaking of the springs, which gush out in the plains of the torrid zone, or at a small elevation, I must observe in general, that it is only in regions where the mean temperature of summer essentially differs from that of the whole year, that the inhabitants can drink spring water extremely cold during the season of the great heats. The Laplanders, near Umea and Sorsele, in the 65th degree of latitude, drink spring-water, the temperature of which, in the month of August, is scarcely two or three degrees above the freezing point; while in the day the heat of the air rises in the shade, in the same northern regions, to 26 or 27 degrees. In the temperate climates of France and Germany, the difference between the air and the springs never exceeds 16 or 17 degrees; between the tropics it seldom rises to 5 or 6

* Vol. II. p. 36, 142, 184.

+ Kongl. Vetenks. Acad. Nya Handl., 1809, p. 205.

degrees. It is easy to account for these phenomena, on recollecting, that the interior of the globe, and the subterraneous waters, have a temperature almost identical with the annual mean temperature of the air; and that the latter differs from the mean heat of the summer in proportion to the distance from the equator. The dip of the needle at Quetepe was 42.7° of the centesimal division. The cyanometer indicated for the colour of the sky at the zenith only 14°; no doubt because the season of the rains had begun some days before, and the air was already mingled with vapours *.

From the top of a hill of sandstone, which overlooks the spring of Quetepe, we had a magnificent view of the sea, cape Macanao, and the peninsula of Maniquarez. An immense forest extended itself at our feet to the edge of the ocean. The tops of the trees, intertwined with lianas, crowned with long wreaths of flowers, formed a vast carpet of verdure, the dark tint

Deluc's hygrometer, 48°;
From Quetepe I found by

At four in the afternoon; centigrade thermometer, 26.5°. the compass the bearings of Cape Macanao N. 26° W. The angle between the Cape and the Valley of San Juan in the Island of Margaretta is 29° 28'. The distance in a straight line from Quetepe to Cumana appears to be three leagues

and a half.

of which augmented the splendor of the aerial light. The aspect of this spot struck us the more, as we then first beheld those great masses of tropical vegetation. On the hill of Quetepe, at the foot of the malpighia cocollobæfolia, the leaves of which are extremely coriaceous, we gathered, among tufts of the polygala montana, the first melastomas, especially that beautiful species described under the name of the melastoma rufescens. The remembrance of this spot will remain long impressed on our minds. The traveller preserves a fond predilection for those places, where he meets with a group of plants which he had never before beheld in their wild state.

As we advanced toward the south-west, the soil became dry and sandy. We climbed a group of mountains, which separate the coast from the vast plains, or savannahs, bordered by the Oroonoko. That part of this group, over which passes the road to Cumanacoa, is destitute of vegetation, and has steep declivities toward both the north and the south. It is designated by the name of the Impossible, because it is believed, that, in the case of the landing of an enemy, this ridge of mountains would offer an asylum to the inhabitants of Cumana. We reached the top a little before sun-set, and I had scarcely time to take a few horary angles, to

determine the longitude of the place by means of the chronometer *.

The view from the Impossible is finer and more extensive than that from the table-land of Quetepe. We distinguished clearly by the naked eye the flattened top of the Brigantine, the position of which it would be important to fix accurately, the landing-place, and the road of Cumana. The rocky coast of the peninsula of Araya appeared at it's full length. We were particularly struck with the extraordinary configuration of a port, known by the name of Laguna Grande, or Laguna del Obispo. A vast basin, surrounded by high mountains, communicates with the Gulf of Cariaco by a narrow channel, which admits only of the passage of one ship at a time. This port, of which Mr. Fidalgo has sketched the plan minutely, is ca-pable of containing several squadrons at once. It is an uninhabited place, but annually frequented by vessels, which carry mules to the

See my Astronomical Observations, vol. i, page 94. On account of the distance of the southern part of the gulf of Cariaco, the latitude must be nearly 10° 23'. I took the bearings of the road of Cumana, N. 61° 21' W.; of Cape Macanao, N. 29° 27′ W.; of Laguna Grande, on the northern coast of the gulf of Cariaco, N. 3° 10' W.; of the Cerro del Bergantin, (centre of the Mesa) S. 27° 5' W. Shortest distance from the sea 3 or 4 miles. The angles were taken some with a sextant, some with the nautical compass; the latter are corrected by the magnetic variation.

West India Islands. There are some pasture grounds at the bottom of the bay. We traced the sinuosities of this arm of the sea, which, like a river, has dug a bed between perpendicular rocks destitute of vegetation. This singular view reminded us of the back-ground of the fanciful landscape, with which Leonardo da Vinci has decorated his famous portrait of Gioconda *.

We could observe by the chronometer the moment when the disk of the sun touched the horizon of the sea. The first contact was at 6h 8′ 13′′; the second, at 6h 10′ 26′′ of mean time. This observation, which is not unimportant for the theory of terrestrial refractions, was made on the summit of the mountain, at the absolute height of 296 toises. The setting of the sun was attended by a very rapid cooling of the air. Three minutes after the last apparent contact of the disk with the horizon of the sea, the thermometer suddenly fell from 25.2° to 21.3°. Was this extraordinary refrigeration owing to some descending current? The air was however calm, and no horizontal wind was felt.

We passed the night in a house where there was a military post of eight men, under the command of a Spanish serjeant. It is an hos

* Mona Lisa, wife of Francesco del Giocondo.