Personal Narrative of Travels to the Equinoctial Regions of America, During the Years 1799-1804, Vol.2 — Chapter 2.16, Part 2

Since the increase of agricultural industry in the valleys of Aragua, the little rivers which run into the lake of Valencia can no longer be regarded as positive supplies during the six months succeeding December.

They remain dried up in the lower part of their course, because the planters of indigo, coffee, and sugar-canes, have made frequent drainings (azequias), in order to water the ground by trenches.

We may observe also, that a pretty considerable river, the Rio Pao, which rises at the entrance of the Llanos, at the foot of the range of hills called La Galera, heretofore mingled its waters with those of the lake, by uniting with the Cano de Cambury, on the road from the town of Nueva Valencia to Guigue.

The course of this river was from south to north.

At the end of the seventeenth century, the proprietor of a neighbouring plantation dug at the back of the hill a new bed for the Rio Pao.

He turned the river; and, after having employed part of the water for the irrigation of his fields, he caused the rest to flow at a venture southward, following the declivity of the Llanos.

In this new southern direction the Rio Pao, mingled with three other rivers, the Tinaco, the Guanarito, and the Chilua, falls into the Portuguesa, which is a branch of the Apure.

It is a remarkable phenomenon, that by a particular position of the ground, and the lowering of the ridge of division to south-west, the Rio Pao separates itself from the little system of interior rivers to which it originally belonged, and for a century past has communicated, through the channel of the Apure and the Orinoco, with the ocean.

What has been here effected on a small scale by the hand of man, nature often performs, either by progressively elevating the level of the soil, or by those falls of the ground occasioned by violent earthquakes.

It is probable, that in the lapse of ages, several rivers of Soudan, and of New Holland, which are now lost in the sands, or in inland basins, will open for themselves a course to the shores of the ocean.

We cannot at least doubt, that in both continents there are systems of interior rivers, which may be considered as not entirely developed;

and which communicate with each other, either in the time of great risings, or by permanent bifurcations.

The Rio Pao has scooped itself out a bed so deep and broad, that in the season of rains, when the Cano Grande de Cambury inundates all the land to the north-west of Guigue, the waters of this Cano, and those of the lake of Valencia, flow back into the Rio Pao itself; so that this river, instead of adding water to the lake, tends rather to carry it away.

We see something similar in North America, where geographers have represented on their maps an imaginary chain of mountains, between the great lakes of Canada and the country of the Miamis.

At the time of floods, the waters flowing into the lakes communicate with those which run into the Mississippi; and it is practicable to proceed by boats from the sources of the river St. Mary to the Wabash, as well as from the Chicago to the Illinois.

These analogous facts appear to me well worthy of the attention of hydrographers.

The land that surrounds the lake of Valencia being entirely flat and even, a diminution of a few inches in the level of the water exposes to view a vast extent of ground covered with fertile mud and organic remains.

* (* This I observed daily in the Lake of Mexico.

) In proportion as the lake retires, cultivation advances towards the new shore.

These natural desiccations, so important to agriculture, have been considerable during the last ten years, in which America has suffered from great droughts.

Instead of marking the sinuosities of the present banks of the lake, I have advised the rich landholders in these countries to fix columns of granite in the basin itself, in order to observe from year to year the mean height of the waters.

The Marquis del Toro has undertaken to put this design into execution, employing the fine granite of the Sierra de Mariara, and establishing limnometers, on a bottom of gneiss rock, so common in the lake of Valencia.

It is impossible to anticipate the limits, more or less narrow, to which this basin of water will one day be confined, when an equilibrium between the streams flowing in and the produce of evaporation and filtration, shall be completely established.

The idea very generally spread, that the lake will soon entirely disappear, seems to me chimerical.

If in consequence of great earthquakes, or other causes equally mysterious, ten very humid years should succeed to long droughts; if the mountains should again become clothed with forests, and great trees overshadow the shore and the plains of Aragua, we should more probably see the volume of the waters augment, and menace that beautiful cultivation which now trenches on the basin of the lake.

While some of the cultivators of the valleys of Aragua fear the total disappearance of the lake, and others its return to the banks it has deserted, we hear the question gravely discussed at Caracas, whether it would not be advisable, in order to give greater extent to agriculture, to conduct the waters of the lake into the Llanos, by digging a canal towards the Rio Pao.

The possibility* of this enterprise cannot be denied, particularly by having recourse to tunnels, or subterranean canals.

(The dividing ridge, namely, that which divides the waters between the valleys of Aragua and the Llanos, lowers so much towards the west of Guigue, as we have already observed, that there are ravines which conduct the waters of the Cano de Cambury, the Rio Valencia, and the Guataparo, in the time of floods, to the Rio Pao; but it would be easier to open a navigable canal from the lake of Valencia to the Orinoco, by the Pao, the Portuguesa, and the Apure, than to dig a draining canal level with the bottom of the lake.

This bottom, according to the sounding, and my barometric measurements, is 40 toises less than 222, or 182 above the surface of the ocean.

On the road from Guigue to the Llanos, by the table-land of La Villa de Cura, I found, to the south of the dividing ridge, and on its southern declivity, no point of level corresponding to the 182 toises, except near San Juan.

The absolute height of this village is 194 toises.

But, I repeat that, farther towards the west, in the country between the Cano de Cambury and the sources of the Rio Pao, which I was not able to visit, the point of level of the bottom of the lake is much further north.

) The progressive retreat of the waters has given birth to the beautiful and luxuriant plains of Maracay, Cura, Mocundo, Guigue, and Santa Cruz del Escoval, planted with tobacco, sugar-canes, coffee, indigo, and cacao; but how can it be doubted for a moment that the lake alone spreads fertility over this country?

If deprived of the enormous mass of vapour which the surface of the waters sends forth daily into the atmosphere, the valleys of Aragua would become as dry and barren as the surrounding mountains.

The mean depth of the lake is from twelve to fifteen fathoms; the deepest parts are not, as is generally admitted, eighty, but thirty-five or forty deep.

Such is the result of soundings made with the greatest care by Don Antonio Manzano.

When we reflect on the vast depths of all the lakes of Switzerland, which, notwithstanding their position in high valleys, almost reach the level of the Mediterranean, it appears surprising that greater cavities are not found at the bottom of the lake of Valencia, which is also an Alpine lake.

The deepest places are between the rocky island of Burro and the point of Cana Fistula, and opposite the high mountains of Mariara.

But in general the southern part of the lake is deeper than the northern: nor must we forget that, if all the shores be now low, the southern part of the basin is the nearest to a chain of mountains with abrupt declivities; and we know that even the sea is generally deepest where the coast is elevated, rocky, or perpendicular.

The temperature of the lake at the surface during my abode in the valleys of Aragua, in the month of February, was constantly from 23 to 23. 7 degrees, consequently a little below the mean temperature of the air.

This may be from the effect of evaporation, which carries off caloric from the air and the water; or because a great mass of water does not follow with an equal rapidity the changes in the temperature of the atmosphere, and the lake receives streams which rise from several cold springs in the neighbouring mountains.

I have to regret that, notwithstanding its small depth, I could not determine the temperature of the water at thirty or forty fathoms.

I was not provided with the thermometrical sounding apparatus which I had used in the Alpine lakes of Salzburg, and in the Caribbean Sea.

The experiments of Saussure prove that, on both sides of the Alps, the lakes which are from one hundred and ninety to two hundred and seventy-four toises of absolute elevation* (* This is the difference between the absolute elevations of the lakes of Geneva and Thun.

) have, in the middle of winter, at nine hundred, at six hundred, and sometimes even at one hundred and fifty feet of depth, a uniform temperature from 4. 3 to 6 degrees: but these experiments have not yet been repeated in lakes situated under the torrid zone.

The strata of cold water in Switzerland are of an enormous thickness.

They have been found so near the surface in the lakes of Geneva and Bienne, that the decrement of heat in the water was one centesimal degree for ten or fifteen feet; that is to say, eight times more rapid than in the ocean, and forty-eight times more rapid than in the atmosphere.

In the temperate zone, where the heat of the atmosphere sinks to the freezing point, and far lower, the bottom of a lake, even were it not surrounded by glaciers and mountains covered with eternal snow, must contain particles of water which, having during winter acquired at the surface the maximum of their density, between 3. 4 and 4. 4 degrees, have consequently fallen to the greatest depth.

Other particles, the temperature of which is +0. 5 degrees, far from placing themselves below the stratum at 4 degrees, can only find their hydrostatic equilibrium above that stratum.

They will descend lower only when their temperature is augmented 3 or 4 degrees by the contact of strata less cold.

If water in cooling continued to condense uniformly to the freezing point, there would be found, in very deep lakes and basins having no communication with each other (whatever the latitude of the place), a stratum of water, the temperature of which would be nearly equal to the maximum of refrigeration above the freezing point, which the lower regions of the ambient atmosphere annually attain.

Hence it is probable, that, in the plains of the torrid zone, or in the valleys but little elevated, the mean heat of which is from 25. 5 to 27 degrees, the temperature of the bottom of the lakes can never be below 21 or 22 degrees.

If in the same zone the ocean contain at depths of seven or eight hundred fathoms, water the temperature of which is at 7 degrees, that is to say, twelve or thirteen degrees colder than the maximum of the heat* of the equinoctial atmosphere over the sea, I think it must be considered as a direct proof of a submarine current, carrying the waters of the pole towards the equator.

(* It is almost superfluous to observe that I am considering here only that part of the atmosphere lying on the ocean between 10 degrees north and 10 degrees south latitude.

Towards the northern limits of the torrid zone, in latitude 23 degrees, whither the north winds bring with an extreme rapidity the cold air of Canada, the thermometer falls at sea as low as 16 degrees, and even lower.

) We will not here solve the delicate problem, as to the manner in which, within the tropics and in the temperate zone, (for example, in the Caribbean Sea and in the lakes of Switzerland,) these inferior strata of water, cooled to 4 or 7 degrees, act upon the temperature of the stony strata of the globe which they cover; and how these same strata, the primitive temperature of which is, within the tropics, 27 degrees, and at the lake of Geneva 10 degrees, react upon the half-frozen waters at the bottom of the lakes, and of the equinoctial ocean.

These questions are of the highest importance, both with regard to the economy of animals that live habitually at the bottom of fresh and salt waters, and to the theory of the distribution of heat in lands surrounded by vast and deep seas.

The lake of Valencia is full of islands, which embellish the scenery by the picturesque form of their rocks, and the beauty of the vegetation with which they are covered: an advantage which this tropical lake possesses over those of the Alps.

The islands are fifteen in number, distributed in three groups;* without reckoning Morro and Cabrera, which are already joined to the shore.

(* The position of these islands is as follows: northward, near the shore, the Isla de Cura; on the south-east, Burro, Horno, Otama, Sorro, Caiguira, Nuevos Penones, or the Aparecidos; on the north-west, Cabo Blanco, or Isla de Aves, and Chamberg; on the south-west, Brucha and Culebra.

In the centre of the lake rise, like shoals or small detached rocks, Vagre, Fraile, Penasco, and Pan de Azucar.

) They are partly cultivated, and extremely fertile on account of the vapours that rise from the lake.

Burro, the largest of these islands, is two miles in length, and is inhabited by some families of mestizos, who rear goats.

These simple people seldom visit the shore of Mocundo.

To them the lake appears of immense extent; they have plantains, cassava, milk, and a little fish.

A hut constructed of reeds; hammocks woven from the cotton which the neighbouring fields produce; a large stone on which the fire is made; the ligneous fruit of the tutuma (the calabash) in which they draw water, constitute their domestic establishment.

An old mestizo who offered us some goat's milk had a beautiful daughter.

We learned from our guide, that solitude had rendered him as mistrustful as he might perhaps have been made by the society of men.

The day before our arrival, some hunters had visited the island.

They were overtaken by the shades of night; and preferred sleeping in the open air to returning to Mocundo.

This news spread alarm throughout the island.

The father obliged the young girl to climb up a very lofty zamang or acacia, which grew in the plain at some distance from the hut, while he stretched himself at the foot of the tree, and did not permit his daughter to descend till the hunters had departed.

The lake is in general well stocked with fish; though it furnishes only three kinds, the flesh of which is soft and insipid, the guavina, the vagre, and the sardina.

The two last descend into the lake with the streams that flow into it.

The guavina, of which I made a drawing on the spot, is 20 inches long and 3. 5 broad.

It is perhaps a new species of the genus erythrina of Gronovius.

It has large silvery scales edged with green.

This fish is extremely voracious, and destroys other kinds.

The fishermen assured us that a small crocodile, the bava,* which often approached us when we were bathing, contributes also to the destruction of the fish.

(* The bava, or bavilla, is very common at Bordones, near Cumana.

See volume 1. The name of bava, baveuse, has misled M. Depons; he takes this reptile for a fish of our seas, the Blennius pholis.

Voyage a la Terre Ferme.

The Blennius pholis, smooth blenny, is called by the French baveuse (slaverer), in Spanish, baba.

) We never could succeed in procuring this reptile so as to examine it closely: it generally attains only three or four feet in length.

It is said to be very harmless; its habits however, as well as its form, much resemble those of the alligator (Crocodilus acutus).

It swims in such a manner as to show only the point of its snout, and the extremity of its tail; and places itself at mid-day on the bare beach.

It is certainly neither a monitor (the real monitors living only in the old continent,) nor the sauvegarde of Seba (Lacerta teguixin,) which dives and does not swim.

It is somewhat remarkable that the lake of Valencia, and the whole system of small rivers flowing into it, have no large alligators, though this dangerous animal abounds a few leagues off in the streams which flow either into the Apure or the Orinoco, or immediately into the Caribbean Sea between Porto Cabello and La Guayra.

In the islands that rise like bastions in the midst of the waters, and wherever the rocky bottom of the lake is visible, I recognised a uniform direction in the strata of gneiss.

This direction is nearly that of the chains of mountains on the north and south of the lake.

In the hills of Cabo Blanco there are found among the gneiss, angular masses of opaque quartz, slightly translucid on the edges, and varying from grey to deep black.

This quartz passes sometimes into hornstein, and sometimes into kieselschiefer (schistose jasper).

I do not think it constitutes a vein.

The waters of the lake* decompose the gneiss by erosion in a very extraordinary manner.

(* The water of the lake is not salt, as is asserted at Caracas.

It may be drunk without being filtered.

On evaporation it leaves a very small residuum of carbonate of lime, and perhaps a little nitrate of potash.

It is surprising that an inland lake should not be richer in alkaline and earthy salts, acquired from the neighbouring soils.

I have found parts of it porous, almost cellular, and split in the form of cauliflowers, fixed on gneiss perfectly compact.

Perhaps the action ceases with the movement of the waves, and the alternate contact of air and water.

The island of Chamberg is remarkable for its height.

It is a rock of gneiss, with two summits in the form of a saddle, and raised two hundred feet above the surface of the water.

The slope of this rock is barren, and affords only nourishment for a few plants of clusia with large white flowers.

But the view of the lake and of the richly cultivated neighbouring valleys is beautiful, and their aspect is wonderful after sunset, when thousands of aquatic birds, herons, flamingoes, and wild ducks cross the lake to roost in the islands, and the broad zone of mountains which surrounds the horizon is covered with fire.

The inhabitants, as we have already mentioned, burn the meadows in order to produce fresher and finer grass.

Gramineous plants abound, especially at the summit of the chain; and those vast conflagrations extend sometimes the length of a thousand toises, and appear like streams of lava overflowing the ridge of the mountains.

When reposing on the banks of the lake to enjoy the soft freshness of the air in one of those beautiful evenings peculiar to the tropics, it is delightful to contemplate in the waves as they beat the shore, the reflection of the red fires that illumine the horizon.

Among the plants which grow on the rocky islands of the lake of Valencia, many have been believed to be peculiar to those spots, because till now they have not been discovered elsewhere.

Such are the papaw-trees of the lake; and the tomato* of the island of Cura.

(* The tomatoes are cultivated, as well as the papaw-tree of the lake, in the Botanical Garden of Berlin, to which I had sent some seeds.

) The latter differs from our Solanum lycopersicum; the fruit is round and small, but has a fine flavour; it is now cultivated at La Victoria, at Nueva Valencia, and everywhere in the valleys of Aragua.

The papaw-tree of the lake (papaya de la laguna) abounds also in the island of Cura and at Cabo Blanco; its trunk shoots higher than that of the common papaw (Carica papaya), but its fruit is only half as large, perfectly spherical, without projecting ribs, and four or five inches in diameter.

When cut open it is found quite filled with seeds, and without those hollow places which occur constantly in the common papaw.

The taste of this fruit, of which I have often eaten, is extremely sweet.

* (* The people of the country attribute to it an astringent quality, and call it tapaculo.

) I know not whether it be a variety of the Carica microcarpa, described by Jacquin.

The environs of the lake are insalubrious only in times of great drought, when the waters in their retreat leave a muddy sediment exposed to the rays of the sun.

The banks, shaded by tufts of Coccoloba barbadensis, and decorated with fine liliaceous plants,* (* Pancratium undulatum, Amaryllis nervosa.

) remind us, by the appearance of the aquatic vegetation, of the marshy shores of our lakes in Europe.

We find there, pondweed (potamogeton), chara, and cats'-tail three feet high, which it is difficult not to confound with the Typha angustifolia of our marshes.

It is only after a careful examination, that we recognise each of these plants for distinct species,* (* Potamogeton tenuifolium, Chara compressa, Typha tenuifolia.

) peculiar to the new continent.

How many plants of the straits of Magellan, of Chile, and the Cordilleras of Quito have formerly been confounded with the productions of the northern temperate zone, owing to their analogy in form and appearance.

The inhabitants of the valleys of Aragua often inquire why the southern shore of the lake, particularly the south-west part towards los Aguacotis, is generally more shaded, and exhibits fresher verdure than the northern side.

We saw, in the month of February, many trees stripped of their foliage, near the Hacienda de Cura, at Mocundo, and at Guacara; while to the south-east of Valencia everything presaged the approach of the rains.

I believe that in the early part of the year, when the sun has southern declination, the hills around Valencia, Guacara, and Cura are scorched by the heat of the solar rays, while the southern shore receives, along with the breeze when it enters the valley by the Abra de Porto Cabello, an atmosphere which has crossed the lake, and is loaded with aqueous vapour.

On this southern shore, near Guaruto, are situated the finest plantations of tobacco in the whole province.