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able in other respects, so fleeting, and so independent on each other, evidently shows that they must be attached to one and the same round body which makes them revolve altogether with a common motion. Hence it has been conéluded that the Sun revolves upon itself with the general motion of these spots, that is, in 25 days and a half, in like manner as our earth revolves in 24 hours. The same calculation, applied to the spots which have been discovered on the other planets, has in like manner made us acquainted with their rotation.

As to the nature of these solar spots, it is absolutely unknown. Herschell is of opinion that luminous clouds float in the inflamed atmosphere of this star, as clouds of vapour float in ours. He supposes that the body of the Sun is opaque and dark; and that the black spots observed there at intervals are merely the summits of very elevated mountains, which the solar clouds permit us to see between their openings. Other astronomers think that the globe of the Sun is on fire, and that the spots are merely immense scoria, launched on the surface of that mass by the terrible explosions of which our terrestrial volcanoes afford but a feeble picture. But whatever may be thought of these conjectures, it seems sufficient for us to know, that the solar spots are trifling compared with the immense mass of that star; and that the eruptions of which they are perhaps the effect take place at too great a distance from our earth to produce the least cffect upon it. Generally speak

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(From Journal of Science and the Arts.) I

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

lake.

Lalagunilla, the small 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 on 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

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. J

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.

the environs constantly pass some months of the year at Lalagunilla.

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 c.eature I could observe was an insect on the borders of the lake, which appeared to me a species of spider.

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 ten 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 When the period for the exSierra Neveda truly sublime, a traction of the Urao arrives, residence here is delightful, and which is every two years, those many families from Merida and Indians of Lalagunilla, who are

These waters having a strengthening quality, convalescents resort thither in the morning to bathe, and derive great benefit from them in some cutaneous diseases. In many disorders incident to horses they are likewise very efficacious.

RHODES

HOUSE

OXFORD

devoted

devoted to this employment, and who are called Huragueros, 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 without 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 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 difliculty of extracting the Urao may easily be imagined, but what is much worse, considerable danger attends it. If the Indian diver happens to lose his hold of his pole, or if some other accident prevent his rising promptly to the surface of the water, and indeed the Indians of Lalagunilla 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 trifling; 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 Captaingeneral 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 superintendant 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

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 plea

sure.

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. Guy 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 subcorbonate 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 nuriate of soda, and this being ascertained it would perhaps contribute to explain the formation. of hatron at such a considerable height above the level of the sea, which is more than sixty leagues distant from Lalagunilla.

MISCELLANIES.

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MUSTY WHEAT

the large quantities of corn which, during the last harvest, have been

HE following letter at this housed in a damp state, and on

Time deserves particular at

tention; the scientific author, Mr. Hatchett, is well known to be one of the most eminent chymists in Europe.

TO THE RIGHT HON. SIR JOSEPH

BANKS, BART. G. C. B. P. R. S. &c. Read before the Royal Society, Dec.

66

5, 1816.

My Dear Sir,-The very great loss which this country formerly experienced by a considerable part of imported grain having become containinated by must, induced me several years past to direct my attention towards discovering some simple and economical method by which this taint could be removed, and you well know that my endeavours were successful; but as circumstances at that time, and since, did not appear to require that great publicity should be given to this process, I contented myself with describing it to you and a few of my other friends. Now, however, when I reflect on

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the great importations which are expected, with the extreme probability that a considerable part may have contracted must, and that thus the object of importation may be partially frustrated by the destruction of a large portion of grain, and the consequent increase in the price of the remainder, think it incumbent on me, by addressing this letter to you, to lose no time in publishing a process, by which corn, however musty, may be completely puri fied, with scarcely any loss of quantity, with very little expense, and without requiring previous chymical knowledge or chymical apparatus.

"The experiments which I made were confined to wheat, as being of the greatest importance; but there can be no doubt that oats and other grain may be restored to sweetness with equal success and I have also additional satisfaction from being enabled to state, that the efficacy of the process may be ascertained by

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