We must not be surprised that fertile islands, so near Terra Firma, are not now inhabited. It was only at the early period of the discovery, and whilst the Caribbees, Chaymas, and Cumanagotos were still masters of the coast, that the Spaniards formed settlements at Cubagua and Margareta. When the natives were subdued, or driven southward in the direction of the savannahs, the preference was given to settlements on the continent, where there was a choice of land, and where there were Indians, who might be treated like beasts of burden. Had the little islands of Tortuga, Blanquilla, and Orchilla been situated in the group of the Antilles, they would not have remained without traces of cultivation.
Vessels of heavy burthen pass between the main land and the most southern of the Piritu Islands. Being very low, their northern point is dreaded by pilots who near the coast in those latitudes. When we found ourselves to westward of the Morro of Barcelona, and the mouth of the river Unare, the sea, till then calm, became agitated and rough in proportion as we approached Cape Codera. The influence of that vast promontory is felt from afar, in that part of the Caribbean Sea. The length of the passage from Cumana to La Guayra depends on the degree of ease or difficulty with which Cape Codera can be doubled. Beyond this cape the sea constantly runs so high, that we can scarcely believe we are near a coast where (from the point of Paria as far as Cape San Roman) a gale of wind is never known. On the 20th of November at sunrise we were so far advanced, that we might expect to double the cape in a few hours. We hoped to reach La Guayra the same day; but our Indian pilot being afraid of the privateers who were near that port, thought it would be prudent to make for land, and anchor in the little harbour of Higuerote, which we had already passed, and await the shelter of night to proceed on our voyage.
On the 20th of November at nine in the morning we were at anchor in the bay just mentioned, situated westward of the mouth of the Rio Capaya. We found there neither village nor farm, but merely two or three huts, inhabited by Mestizo fishermen. Their livid hue, and the meagre condition of their children, sufficed to remind us that this spot is one of the most unhealthy of the whole coast. The sea has so little depth along these shores, that even with the smallest barks it is impossible to reach the shore without wading through the water. The forests come down nearly to the beach, which is covered with thickets of mangroves, avicennias, manchineel-trees, and that species of suriana which the natives call romero de la mar.* (* Suriana maritima.) To these thickets, and particularly to the exhalations of the mangroves, the extreme insalubrity of the air is attributed here, as in other places in both Indies. On quitting the boats, and whilst we were yet fifteen or twenty toises distant from land, we perceived a faint and sickly smell, which reminded me of that diffused through the galleries of deserted mines, where the lights begin to be extinguished, and the timber is covered with flocculent byssus. The temperature of the air rose to 34 degrees, heated by the reverberation from the white sands which form a line between the mangroves and the great trees of the forest. As the shore descends with a gentle slope, small tides are sufficient alternately to cover and uncover the roots and part of the trunks of the mangroves. It is doubtless whilst the sun heats the humid wood, and causes the fermentation, as it were, of the ground, of the remains of dead leaves and of the molluscs enveloped in the drift of floating seaweed, that those deleterious gases are formed, which escape our researches. We observed that the sea-water, along the whole coast, acquired a yellowish brown tint, wherever it came into contact with the mangrove trees.
Struck with this phenomenon, I gathered at Higuerote a considerable quantity of branches and roots, for the purpose of making some experiments on the infusion of the mangrove, on my arrival at Caracas. The infusion in warm water had a brown colour and an astringent taste. It contained a mixture of extractive matter and tannin. The rhizophora, the mistletoe, the cornel-tree, in short, all the plants which belong to the natural families of the lorantheous and the caprifoliaceous plants, have the same properties. The infusion of mangrove-wood, kept in contact with atmospheric air under a glass jar for twelve days, was not sensibly deteriorated in purity. A little blackish flocculent sediment was formed, but it was attended by no sensible absorption of oxygen. The wood and roots of the mangrove placed under water were exposed to the rays of the sun. I tried to imitate the daily operations of nature on the coasts at the rise of the tide. Bubbles of air were disengaged, and at the expiration of ten days they formed a volume of thirty-three cubic inches. They were a mixture of azotic gas and carbonic acid. Nitrous gas scarcely indicated the presence of oxygen.* (* In a hundred parts there were eighty-four of nitrogen, fifteen of carbonic acid gas that the water had not absorbed, and one of oxygen.) Lastly, I set the wood and the roots of the mangrove thoroughly wetted, to act on a given volume of atmospheric air in a phial with a ground-glass stopple. The whole of the oxygen disappeared; and, far from being superseded by carbonic acid, lime-water indicated only 0.02. There was even a diminution of the volume of air, more than correspondent with the oxygen absorbed. These slight experiments led me to conclude that it is the moistened bark and wood which act upon the atmosphere in the forests of mangrove-trees, and not the water strongly tinged with yellow, forming a distinct band along the coasts. In pursuing the different stages of the decomposition of the ligneous matter, I observed no appearance of a disengagement of sulphuretted hydrogen, to which many travellers attribute the smell perceived amidst mangroves. The decomposition of the earthy and alkaline sulphates, and their transition to the state of sulphurets, may no doubt favour this disengagement in many littoral and marine plants; for instance, in the fuci: but I am rather inclined to think that the rhizophora, the avicennia, and the conocarpus, augment the insalubrity of the air by the animal matter which they contain conjointly with tannin. These shrubs belong to the three natural families of the Lorantheae, the Combretaceae, and the Pyrenaceae, in which the astringent principle abounds; this principle accompanies gelatin, even in the bark of beech, alder, and nut-trees.
Moreover, a thick wood spreading over marshy grounds would diffuse noxious exhalations in the atmosphere, even though that wood were composed of trees possessing in themselves no deleterious properties. Wherever mangroves grow on the sea-shore, the beach is covered with infinite numbers of molluscs and insects. These animals love shade and faint light, and they find themselves sheltered from the shock of the waves amid the scaffolding of thick and intertwining roots, which rises like lattice-work above the surface of the waters. Shell-fish cling to this lattice; crabs nestle in the hollow trunks; and the seaweeds, drifted to the coast by the winds and tides, remain suspended on the branches which incline towards the earth. Thus, maritime forests, by the accumulation of a slimy mud between the roots of the trees, increase the extent of land. But whilst these forests gain on the sea, they do not enlarge their own dimensions; on the contrary, their progress is the cause of their destruction. Mangroves, and other plants with which they live constantly in society, perish in proportion as the ground dries and they are no longer bathed with salt water. Their old trunks, covered with shells, and half-buried in the sand, denote, after the lapse of ages, the path they have followed in their migrations, and the limits of the land which they have wrested from the ocean.
The bay of Higuerote is favourably situated for examining Cape Codera, which is there seen in its full extent seven miles distant. This promontory is more remarkable for its size than for its elevation, being only about two hundred toises high. It is perpendicular on the north-west and east. In these grand profiles the dip of the strata appears to be distinguishable. Judging from the fragments of rock found along the coast, and from the hills near Higuerote, Cape Codera is not composed of granite with a granular texture, but of a real gneiss with a foliated texture. Its laminae are very broad and sometimes sinuous.* (* Dickflasriger gneiss.) They contain large nodules of reddish feldspar and but little quartz. The mica is found in superposed lamellae, not isolated. The strata nearest the bay were in the direction of 60 degrees north-east, and dipped 80 degrees to north-west. These relations of direction and of dip are the same at the great mountain of the Silla, near Caracas, and to the east of Maniquarez, in the isthmus of Araya. They seem to prove that the primitive chain of that isthmus, after having been ruptured or swallowed up by the sea along a space of thirty-five leagues,* (* Between the meridians of Maniquarez and Higuerote.) appears anew in Cape Codera, and continues westward as a chain of the coast.
I was assured that, in the interior of the earth, south of Higuerote, limestone formations are found. The gneiss did not act upon the magnetic needle; yet along the coast, which forms a cove near Cape Codera, and which is covered with a fine forest, I saw magnetic sand mixed with spangles of mica, deposited by the sea. This phenomenon occurs again near the port of La Guayra. Possibly it may denote the existence of some strata of hornblende-schist covered by the waters, in which schist the sand is disseminated. Cape Codera forms on the north an immense spherical segment. A shallow which stretches along its foot is known to navigators by the name of the points of Tutumo and of San Francisco.
The road by land from Higuerote to Caracas, runs through a wild and humid tract of country, by the Montana of Capaya, north of Caucagua, and the valley of Rio Guatira and Guarenas. Some of our fellow-travellers determined on taking this road, and M. Bonpland also preferred it, notwithstanding the continual rains and the overflowing of the rivers. It afforded him the opportunity of making a rich collection of new plants.* (* Bauhinia ferruginea, Brownea racemosa, B ed. Inga hymenaeifolia, I. curiepensis (which Willdenouw has called by mistake I. caripensis), etc.) For my part, I continued alone with the Guaiqueria pilot the voyage by sea; for I thought it hazardous to lose sight of the instruments which we were to make use of on the banks of the Orinoco.
We set sail at night-fall. The wind was unfavourable, and we doubled Cape Codera with difficulty. The surges were short, and often broke one upon another. The sea ran the higher, owing to the wind being contrary to the current, till after midnight. The general motion of the waters within the tropics towards the west is felt strongly on the coast during two-thirds of the year. In the months of September, October, and November, the current often flows eastward for fifteen or twenty days in succession; and vessels on their way from Guayra to Porto Cabello have sometimes been unable to stem the current which runs from west to east, although they have had the wind astern. The cause of these anomalies is not yet discovered. The pilots think they are the effect of gales of wind from the north-west in the gulf of Mexico.
On the 21st of November, at sunrise, we were to the west of Cape Codera, opposite Curuao. The coast is rocky and very elevated, the scenery at once wild and picturesque. We were sufficiently near land to distinguish scattered huts surrounded by cocoa-trees, and masses of vegetation, which stood out from the dark ground of the rocks. The mountains are everywhere perpendicular, and three or four thousand feet high; their sides cast broad and deep shadows upon the humid land, which stretches out to the sea, glowing with the freshest verdure. This shore produces most of those fruits of the hot regions, which are seen in such great abundance in the markets of the Caracas. The fields cultivated with sugar-cane and maize, between Camburi and Niguatar, stretch through narrow valleys, looking like crevices or clefts in the rocks: and penetrated by the rays of the sun, then above the horizon, they presented the most singular contrasts of light and shade.