« AnteriorContinua »
Account of a Soda Lake in South America. By M. PALACIO
FAXAR. Transmitted to the Editor by Charles König, Esq. of the British Museum.
[From the Journal of Science and the Arts, No. II, for 1816.]
In Maracaybo, one of the provinces of Venezuela (48 miles east of Merida, about 8 degrees of N. L. and 70 degrees some minutes of W. Lon.), is a valley, called by the natives Lalagunilla, the small lake. On the south of this valley, which contains an extent of country seven miles in length and five in breadth, runs that branch of the Andes which extends along the coast of Venezuela, and rising in this spot to the line of perpetual snow, forms La Sierra Nevada of Merida.
The waters that descend northwards from La Sierra unite to form the river Chama, which traverses the neighbouring countries, Mucuchies, Merida, Exido, Lalagunilla, and Estanques, and loses itself in the woods which surround the lake of Maracaybo. Those, on the contrary, which descend southwards from the Cordilliera are received by several rivers communicating with the Apure, which falls into the Oronoco. At a considerable height northwards, on La Sierra, is found the species of Cinchona, known in commerce by the appellation of Cinchona of Carthagena.
The north side of Lalagunilla is bounded by a limestone hill. The land rises imperceptibly towards the east and descends gradually several fathoms towards the west, until it reaches that tract of country which produces the Cacao (cocos butiracea.) The bed of the valley is formed of chalk; it is situated about 250 fathoms above the level of the sea.
The village of Lalagunilla is situate in the south of the valley; its inhabitants, a strong laborious people, are Indians, whose only occupation is agriculture and the extraction of the Urao.
Nearly in the centre of the valley is the lake which receives the rain water that descends from the neighbouring mountains; but as even during the greatest drought the lake never becomes dry, it is supposed that it has some springs which supply it with water, independent of the rains. Its dimensions in the rainy season, in the widest part, are two hundred and tep fathoms by one hundred and six. On the eastern side, where the waters are deepest, its depth never exceeds three fathoms. To prevent inundations to the neighbouring cottages, a drain is cut on the south-east side, which carries the waters into the Chama. On the eastern side the waters are very shallow, and being contracted in width, give to the lake a somewhat oval form. It is on this side that many aquatic plants are found. The air of the valley being very dry, the climate mild, the sky serene, the country in a high state of cultivation, and the view of La Sierra Nevada truly sublime, a residence here is delightful, and many families from Merida and the environs constantly pass some months of the year at Lalagu. nilla.
The waters of the lake are impregnated with carbonate of soda, which crystallizes in the dry season, and is in that state by the Indians called Urao. The extraction of this salt, which is employed at Venezuela to prepare the Mò or inspissated juice of tobacco, has been long known and practised at Lalagunilla. At the end of the last century, when the court of Madrid monopolized the cultivation of tobacco, the right of extracting the Urao fell likewise to the crown. On the east side of the lake a magazine was erected for receiving the Urao, and another building as a residence for the Teniente visitador, or captain of Gens d'armes, in whom was vested the government of the lake, with a view to prevent a species of smuggling which the Indians are much inclined to practise, by secretly withdrawing the Urao.
The water of the lake is of a yellowish green colour, of a saponaceous quality, alkaline taste, and peculiar smell. There is no appearance of fish of any kind in these waters; the only living creature I could observe was an insect on the borders of the lake, which appeared to me a species of spider.
These waters having a strengthening quality, convalescents resort thither in the morning to bathe, and derive great bene
fit from them in some cutaneous diseases. lo many disorders incident to horses they are likewise very efficacious.
When the period for the extraction of the Urao arrives, which is every cwo years, those Indians of Lalagunilla, who are devoted to this employment, and who are called Hurague. ros, are embodied at the residence of the Teniente visitador. The Indians employed at this work are easily distinguished, by their hair becoming red. Being embodied, they proceed, in presence of the Gens d'armes, to sound the lake with a long pole, at the end of which is fixed a bar of iron, which serves to break the mineral. Having by these means found the parts where the Urao is most copiously deposited, they divide themselves into different parties (quadrillas), for the sake of facilitating their labour. Each party, composed of eight, ten, or more Indians, fixes a pole in the centre of the district allotted to them. Supported by this pole, the Huragueros plunge into the lake, and beginning by separating a bed of earth which covers the mineral, they proceed to break the Urao. When they suppose that a considerable part of the Urao is separated from the mass, they dive for it, and then rising again above the water, place it in very small canoes (piraguitas), which float round the spot. As there are several Indians who explore the same mine, the work goes on with. out interruption, but the same Huraguero is not able to plunge many times successively. The work, which begins early, and always in presence of the Gens d'armes, who are stationed on the borders of the lake, ceases at six o'clock in the afternoon, when the produce of the day's labour is deposited in the royal magazine, and is afterwards exposed to the heat of the sun.
The extraction, which lasts nearly two months, produces from 1000 to 1600 hundred weight of Urao, which is the quantity consumed in two years at Venezuela; but if more were required the lake would probably furnish upwards of four times that quantity. The difficulty of extracting the Urao may easily be imagined, but what is much worse, considerable danger attends it. If the Indian diver happen to lose his hold of the pole, or if some other accident prevent his rising promptly VOL. VI.
to the surface of the water, and indeed, the Indians of Lala. gunilla are in general but indifferent divers, he is in danger of swallowing more or less of the alkaline solution. If the quantity drank be inconsiderable the bad consequences may be triling; but if he happen to drink largely, he cannot survive it many days. Oil has been had recourse to in vain. Acetic acid might, perhaps, in such cases be administered with better effect. Father Rendon proposed, in 1808, to the Captain-general of Caraccas, to effect the extraction of the Urao by sinking a caisson, which when properly secured should be opened at bottom to get at the soda. This project, which undoubtedly at low water might be realised at a small expense, was rejected as impracticable.
When the extraction of the Urao is completed the superintendent of the tobacco, who resides at Merida, repairs to Lalagunilla, accompanied by the Teniente visitador and others. The salt is weighed and paid for in the proportion of about one real of plata (about seven-pence) the pound. It is then conveyed into the general storehouse for tobacco at Guanare, in the province of Caraccas, whence it is distributed to the lesser warehouses.
If a heap of tobacco leaves covered with the green leaves of other plants be exposed to the sun for a few days, the tobacco begins to ferment. If then put into a press a red liquor may be drawn from it, the exhalations of which are intoxicating, and its taste very pungent. This juice drawn from the tobacco is called Anvir, but when reduced to a syrup, by evaporation, it is termed Mò. If the Mò be mixed with the Urao when dried, roasted, and pulverised, it forms the Mò dulce, if the proportions be preserved of an ounce of Urao to a pound of Mò; or otherwise Chimò, if two or more ounces of Urao be mixed with a pound of Mò.
In the province of Venezuela, and especially in Barinas and part of Caraccas and Maracaybo, Mò is much used and likewise Chimò, which is kept in small horn boxes, and occasionally persons put a little into their mouths. The Mò, and especially the Chimò, produces a copious salivation, stimulating at the same time the nervous system, which in these
climes, where the senses are blunted by the excessive heat, is productive of a degree of pleasure.
It is likewise used in medicine for spasmodic complaints, which in these countries are both frequent and dangerous. It is said that a little Chimò held in the mouth protects swimmers from the electric power of the cramp fish (Trembladores.)
The sale of Tobacco, the Mò dulce, and Chimò, in the Captaincy-general of Venezuela, produced, in 1804, 700,000 piasters, after every expense attending it was paid.
I had the honour of transmitting last year to Baron Humboldt, in Paris, a specimen of the Urao, which Colonel Duran brought to Europe. It was analysed by M. Gay Lussac, who pronounced it to be natron, in no respect different from that found in the lakes of Egypt and Fezzan. The mass neither contains sulphuric nor boracic acid, but a little subcarbonate of ammonia. On comparing the Urao with common subcarbonate of soda, we find that it contains more carbonic acid and less water.
In the environs of Lalagunilla, as well as in the roads to Merida, and especially near the river Albarregas, there are some mountains which are very distinguishable among the others by their superior verdure, and by the abundance of some plants, principally the Rosa de Muerto; and precisely the same species of verdure and the same plants are found on the mountains where are the mines of rock salt at Zipaquira, and at Enemocon of Cundinamarca in New Granada. Finding these similarities, I may venture to form a conjecture that in the environs of Lalagunilla there must likewise exist muriate of soda; and this being ascertained it would perhaps contribute to explain the formation of natron at such a considerable height above the level of the sea, which is more than sixty leagues distant from Lalagunilla.