Volume I Part 20 (1/2)

Vessels of heavy burthen pa.s.s 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 lat.i.tudes.

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 pa.s.sage from c.u.mana 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 pa.s.sed, 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 sh.o.r.es, that even with the smallest barks it is impossible to reach the sh.o.r.e 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 sh.o.r.e 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 quant.i.ty 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 gla.s.s 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-gla.s.s 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-sh.o.r.e, 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. Sh.e.l.l-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 acc.u.mulation 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 sh.e.l.ls, 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.* (* d.i.c.kflasriger 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 s.p.a.ce 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 a.s.sured 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 ma.s.ses 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 sh.o.r.e 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.

The mountain of Niguatar and the Silla of Caracas are the loftiest summits of this littoral chain. The first almost reaches the height of Canigou; it seems as if the Pyrenees or the Alps, stripped of their snows, had risen from the bosom of the ocean; so much more stupendous do mountains appear when viewed for the first time from the sea. Near Caravalleda, the cultivated lands enlarge; we find hills with gentle declivities, and the vegetation rises to a great height. The sugar-cane is here cultivated, and the monks of La Merced have a plantation with two hundred slaves. This spot was formerly extremely subject to fever; and it is said that the air has acquired salubrity since trees have been planted round a small lake, the emanations of which were dreaded, and which is now less exposed to the ardour of the sun. To the west of Caravalleda, a wall of bare rock again projects forward in the direction of the sea, but it has little extent. After having pa.s.sed it, we immediately discovered the pleasantly situated village of Macuto; the black rocks of La Guayra, studded with batteries rising in tiers one over another, and in the misty distance, Cabo Blanco, a long promontory with conical summits, and of dazzling whiteness.

Cocoa-trees border the sh.o.r.e, and give it, under that burning sky, an appearance of fertility.

I landed in the port of La Guayra, and the same evening made preparations for transporting my instruments to Caracas. Having been recommended not to sleep in the town, where the yellow fever had been raging only a few weeks previously, I fixed my lodging in a house on a little hill, above the village of Maiquetia, a place more exposed to fresh winds than La Guayra. I reached Caracas on the 21st of November, four days sooner than M. Bonpland, who, with the other travellers on the land journey, had suffered greatly from the rain and the inundations of the torrents, between Capaya and Curiepe.

Before proceeding further, I will here subjoin a description of La Guayra, and the extraordinary road which leads from thence to the town of Caracas, adding thereto all the observations made by M.

Bonpland and myself, in an excursion to Cabo Blanco about the end of January 1800.

La Guayra is rather a roadstead than a port. The sea is constantly agitated, and s.h.i.+ps suffer at once by the violence of the wind, the tideways, and the bad anchorage. The lading is taken in with difficulty, and the swell prevents the embarkation of mules here, as at New Barcelona and Porto Cabello. The free mulattoes and negroes, who carry the cacao on board the s.h.i.+ps, are a cla.s.s of men remarkable for muscular strength. They wade up to their waists through the water; and it is remarkable that they are never attacked by the sharks, so common in this harbour. This fact seems connected with what I have often observed within the tropics, with respect to other cla.s.ses of animals which live in society, for instance monkeys and crocodiles. In the Missions of the Orinoco, and on the banks of the river Amazon, the Indians, who catch monkeys to sell them, know very well that they can easily succeed in taming those which inhabit certain islands; while monkeys of the same species, caught on the neighbouring continent, die of terror or rage when they find themselves in the power of man. The crocodiles of one lake in the llanos are cowardly, and flee even when in the water; whilst those of another lake will attack with extreme intrepidity. It would be difficult to explain this difference of disposition and habits, by the mere aspect of the respective localities. The sharks of the port of La Guayra seem to furnish an a.n.a.logous example. They are dangerous and blood-thirsty at the island opposite the coast of Caracas, at the Roques, at Bonayre, and at Cura.s.sao; while they forbear to attack persons swimming in the ports of La Guayra and Santa Martha. The natives, who like the ignorant ma.s.s of people in every country, in seeking the explanation of natural phenomena, always have recourse to the marvellous, affirm that in the ports just mentioned, a bishop gave his benediction to the sharks.

The situation of La Guayra is very singular, and can only be compared to that of Santa Cruz in Teneriffe. The chain of mountains which separates the port from the high valley of Caracas, descends almost directly into the sea; and the houses of the town are backed by a wall of steep rocks. There scarcely remains one hundred or one hundred and forty toises breadth of flat ground between the wall and the ocean. The town has six or eight thousand inhabitants, and contains only two streets, running parallel with each other east and west. It is commanded by the battery of Cerro Colorado; and its fortifications along the sea-sh.o.r.e are well disposed, and kept in repair. The aspect of this place has in it something solitary and gloomy; we seemed not to be on a continent, covered with vast forests, but on a rocky island, dest.i.tute of vegetation. With the exception of Cabo Blanco and the cocoa-trees of Maiquetia, no view meets the eye but that of the horizon, the sea, and the azure vault of heaven. The heat is excessive during the day, and most frequently during the night. The climate of La Guayra is justly considered to be hotter than that of c.u.mana, Porto Cabello, and Coro, because the sea-breeze is less felt, and the air is heated by the radiant caloric which the perpendicular rocks emit from the time the sun sets. The examination of the thermometric observations made during nine months at La Guayra by an eminent physician, enabled me to compare the climate of this port, with those of c.u.mana, of the Havannah, and of Vera Cruz. This comparison is the more interesting, as it furnishes an inexhaustible subject of conversation in the Spanish colonies, and among the mariners who frequent those lat.i.tudes. As nothing is more deceiving in such matters than the testimony of the senses, we can judge of the difference of climates only by numerical calculations.

The four places of which we have been speaking are considered as the hottest on the sh.o.r.es of the New World. A comparison of them may serve to confirm what we have several times observed, that it is generally the duration of a high temperature, and not the excess of heat, or its absolute quant.i.ty, which occasions the sufferings of the inhabitants of the torrid zone.

A series of thermometric observations shows, that La Guayra is one of the hottest places on the earth; that the quant.i.ty of heat which it receives in the course of a year is a little greater than that felt at c.u.mana; but that in the months of November, December, and January (at equal distance from the two pa.s.sages of the sun through the zenith of the town), the atmosphere cools more at La Guayra.

May not this cooling, much slighter than that which is felt almost at the same time at Vera Cruz and at the Havannah, be the effect of the more westerly position of La Guayra? The aerial ocean, which appears to form only one ma.s.s, is agitated by currents, the limits of which are fixed by immutable laws; and its temperature is variously modified by the configuration of the lands and seas by which it is sustained. It may be subdivided into several basins, which overflow into each other, and of which the most agitated (for instance, that over the gulf of Mexico, or between the sierra of Santa Martha and the gulf of Darien) have a powerful influence on the refrigeration and the motion of the neighbouring columns of air. The north winds sometimes cause influxes and counter-currents in the south-west part of the Caribbean Sea, which seem, during particular months, to diminish the heat as far as Terra Firma.

At the time of my abode at La Guayra, the yellow fever, or calentura amarilla, had been known only two years; and the mortality it occasioned had not been very great, because the confluence of strangers on the coast of Caracas was less considerable than at the Havannah or Vera Cruz. A few individuals, even creoles and mulattoes, were sometimes carried off suddenly by certain irregular remittent fevers; which, from being complicated with bilious appearances, hemorrhages, and other symptoms equally alarming, appeared to have some a.n.a.logy with the yellow fever. The victims of these maladies were generally men employed in the hard labour of cutting wood in the forests, for instance, in the neighbourhood of the little port of Carupano, or the gulf of Santa Fe, west of c.u.mana. Their death often alarmed the unacclimated Europeans, in towns usually regarded as peculiarly healthy; but the seeds of the sporadic malady were propagated no farther. On the coast of Terra Firma, the real typhus of America, which is known by the names vomito prieto (black vomit) and yellow fever, and which must be considered as a morbid affection sui generis, was known only at Porto Cabello, at Carthagena, and at Santa Martha, where Gastelbondo observed and described it in 1729. The Spaniards recently disembarked, and the inhabitants of the valley of Caracas, were not then afraid to reside at La Guayra. They complained only of the oppressive heat which prevailed during a great part of the year. If they exposed themselves to the immediate action of the sun, they dreaded at most only those attacks of inflammation of the skin or eyes, which are felt everywhere in the torrid zone, and are often accompanied by a febrile affection and congestion in the head. Many individuals preferred the ardent but uniform climate of La Guayra to the cool but extremely variable climate of Caracas; and scarcely any mention was made of the insalubrity of the former port.

Since the year 1797 everything has changed. Commerce being thrown open to other vessels besides those of the mother country, seamen born in colder parts of Europe than Spain, and consequently more susceptible to the climate of the torrid zone, began to frequent La Guayra. The yellow fever broke out. North Americans, seized with the typhus, were received in the Spanish hospitals; and it was affirmed that they had imported the contagion, and that the disease had appeared on board a brig from Philadelphia, even before the vessel had entered the roads of La Guayra. The captain of the brig denied the fact; and a.s.serted that, far from having introduced the malady, his crew had caught it in the port. We know from what happened at Cadiz in 1800, how difficult it is to elucidate facts, when their uncertainty serves to favour theories diametrically opposite one to another. The more enlightened inhabitants of Caracas and La Guayra, divided in opinion, like the physicians of Europe and the United States, on the question of the contagion of yellow fever, cited the instance of the American vessel; some for the purpose of proving that the typhus had come from abroad, and others, to show that it had taken birth in the country itself.

Those who advocated the latter opinion, admitted that an extraordinary alteration had been caused in the const.i.tution of the atmosphere by the overflowings of the Rio de La Guayra. This torrent, which in general is not ten inches deep, was swelled after sixty hours' rain in the mountains, in so extraordinary a manner, that it bore down trunks of trees and ma.s.ses of rock of considerable size. During this flood the waters were from thirty to forty feet in breadth, and from eight to ten feet deep. It was supposed that, issuing from some subterranean basin, formed by successive infiltrations, they had flowed into the recently cleared arable lands. Many houses were carried away by the torrent; and the inundation became the more dangerous for the stores, in consequence of the gate of the town, which could alone afford an outlet to the waters, being accidentally closed. It was necessary to make a breach in the wall on the sea-side. More than thirty persons perished, and the damage was computed at half a million of piastres. The stagnant water, which infected the stores, the cellars, and the dungeons of the public prison, no doubt diffused miasms in the air, which, as a predisposing cause, may have accelerated the development of the yellow fever; but I believe that the inundation of the Rio de la Guayra was no more the primary cause, than the overflowings of the Guadalquivir, the Xenil, and the Gual-Medina, were at Seville, at Ecija, and at Malaga, the primary causes of the fatal epidemics of 1800 and 1804. I examined with attention the bed of the torrent of La Guayra; and found it to consist merely of a barren soil, blocks of mica-slate, and gneiss, containing pyrites detached from the Sierra de Avila, but nothing that could have had any effect in deteriorating the purity of the air.

Since the years 1797 and 1798, at which periods there prevailed dreadful mortality at Philadelphia, St. Lucia, and St. Domingo, the yellow fever has continued its ravages at La Guayra. It has proved fatal not only to the troops newly arrived from Spain, but also to those levied in parts remote from the coasts, in the llanos between Calabozo and Uritucu, regions almost as hot as La Guayra, but favourable to health. This latter fact would seem more surprising, did we not know, that even the natives of Vera Cruz, who are not attacked with typhus in their own town, sometimes sink under it during the epidemics of the Havannah and the United States. As the black vomit finds an insurmountable barrier at the Encero (four hundred and seventy-six toises high), on the declivity of the mountains of Mexico, in the direction of Xalapa, where oaks begin to appear, and the climate begins to be cool and pleasant, so the yellow fever scarcely ever pa.s.ses beyond the ridge of mountains which separates La Guayra from the valley of Caracas. This valley has been exempt from the malady for a considerable time; for we must not confound the vomito and the yellow fever with the irregular and bilious fevers. The c.u.mbre and the Cerro do Avila form a very useful rampart to the town of Caracas, the elevation of which a little exceeds that of the Encero, but of which the mean temperature is above that of Xalapa.

I have published in another work* (* Nouvelle Espagne tome 2.) the observations made by M. Bonpland and myself on the locality of the towns periodically subject to the visitation of yellow fever; and I shall not hazard here any new conjectures on the changes observed in the pathogenic const.i.tution of particular localities. The more I reflect on this subject, the more mysterious appears to me all that relates to those gaseous emanations which we call so vaguely the seeds of contagion, and which are supposed to be developed by a corrupted air, destroyed by cold, conveyed from place to place in garments, and attached to the walls of houses. How can we explain why, for the s.p.a.ce of eighteen years prior to 1794, there was not a single instance of the vomito at Vera Cruz, though the concourse of unacclimated Europeans and of Mexicans from the interior, was very considerable; though sailors indulged in the same excesses with which they are still reproached; and though the town was not so clean as it has been since the year 1800?