XCI. BOOK attending the works amounted to £204,000, and the diamonds sent to the treasury at Rio de Janeiro weighed 115,675 carats. The produce of the gold washings and mines during the same period amounted to £17,300. From these results it appears that the diamonds actually cost government thirty-three shillings and ninepence per carat. These years were remarkably productive, the weight of the diamonds received annually by government is seldom more than two thousand carats. The contraband trade has been carried on to a very great extent; there is every reason to believe that the diamonds imported in this way into Europe, have amounted in value to more than two millions sterling; but as their exportation is attended with much risk, many of them are privately circulated throughout Brazil, and received instead of money. The Portuguese government remained ignorant of many places which abounded in diamonds; a great quantity was collected on the Tibigi, which waters the plains of Corritiva, Cuiaba and other parts of the country, without the knowledge of the public authorities.* These precious stones differ very much in size, some do not weigh the fifth part of a grain; two or three of seventeen carats are seldom found in the course of a year. A long time has elapsed since the negroes found any equal to thirty carats. If a slave be so fortunate as to find one of an octavo (seventeen carats and a half,) he is crowned with flowers, and carried in procession to the administrator, who purchases him from his owner, and gives him his freedom. Severe laws enacted at different times did not restrain men from engaging in the illicit traffic of diamonds. Any one convicted of selling these stones, had his whole property confiscated, and was condemned to perpetual exile in Africa, or to pass the rest of his days in a loathsome Topazes. dungeon. Topazes of different colours are found in Actes de la Société d'Histoire Naturelle de Paris, t. I. p. 78. XCI. Brazil; and it is probable that they are often confounded BOOK with other precious stones, a great many of them are yellow, but white, blue, aqua-marine and other varieties are collected along the sides of the streams in Minas Novas, north-east of Tejuco. There is besides a particular sort of which one side is blue and the other transparent and colourless. The veins at Capao consist of friable earthy talc, quartz, and large crystals of specular iron ore; but the topazes there appear to be broken, they have only one pyramid, are rarely found attached to quartz, and even in these instances the quartz is always fractured and out of its original position. The miners told Mr. Mawe, that they had sometimes seen green topazes; but that traveller supposes that they had been led into this mistake from observing euclase among these minerals; at all events a green topaz has never been sent into Europe. That traveller takes no notice of the Brazilian ruby, a mineral which has been generally believed to be the same as the topaz; it is certain that the yellow topazes of that country may be tinged with a rosy hue by being strongly heated in a crucible. The Brazilian chrysoberyl is susceptible of the finest polish, these gems are seldom met with in Europe, they are much prized and better known in America. M. Cornara, a pupil of the celebrated Werner, tells us, that there are gold mines in the middle ridge of mountains, Gold mines beginning in the neighbourhood of St. Paulo and Villa Rica, and extending to the banks of the river Ytenes. But these mines have not as yet been worked, and all the gold exported from Brazil has been taken from the rivers that rise from the central mountains. Jaragua, famed for its treasures during the seventeenth century, and regarded at that time as the Peru of Brazil, is situated about five leagues to the south-west of St. Paulo. The soil is red, ferruginous, and very deep in many places; it rests on rocks of granite and gneis mixed with amphibole and Hauy, Encyclopédie Méthod. Arts et Métiers. BOOK mica. The gold lies on a stratum of cascalho, or pebbles and gravel incumbent on the solid rock. XCI. The faiscadones, or gold washers, make excavations in the vallies watered by rivers or streams. Some of their works are more than a hundred feet in width, and twenty in depth. Gold is collected below the roots of the grass on many hills, in which there is sufficient water to supply the washings. The metal varies very much in the size of its grains, some are so minute that, if the water be agitated, they float on the surface; it is also found in crystals, and sometimes, though not often, in large masses. The faiscadones choose their washings near a gentle current; and for this reason that part of a river is preferred where it makes a bend or winding. The large stones and upper layers of sand are first removed and the cascalho is then taken up in gamellas or bowls. A bowlful is washed by a single man in less than a quarter of an hour, and it yields, on an average, about a shilling and fourpence worth of gold. All the gold obtained from the different mines or rather washings in the country must be brought to the royal smelting-house. A fifth part is set aside as the king's portion before any gold can be smelted. The bars when cut are put into the hands of the assayer, (ensayador,) who determines their weight and fineness. The value of the bar being ascertained and registered, the Brazilian and Portuguese arms, the number of the register, the mark of the smelting-house, the date of the year, and the degree of fineness are stamped upon it. After the proprietor has submitted to all these forms, he receives a printed ticket, stating the weight of the gold, its value in rees, and the quantity deducted for the royal treasure. Without this instrument, the bar cannot legally pass as the current coin of the realm. It appears from different documents, that seventy or eighty arrobas* of gold were annually smelted at Villa Rica; but * A weight of about 31 lbs. the produce of these washings is not nearly so great at present; Humboldt supposes that it does not exceed in value five millions of piastres. BOOK XCI. The present government, dreading the encroachments of its priests, has declared it unlawful for monks to build convents, or even to reside in Minas Geraes, lest they should in time make themselves masters of the mines. Other metals are found in Brazil; iron ore is obtained in Iron. great quantities, and the village of Yapemema owes its origin to the extensive mines of magnetic iron-stone in Araasojava an adjoining mountain. It is only lately that these mines have been wrought, the manner of working them is still very defective; if a better method of refining the ore were adopted, and the means of communication facilitated, Yapemema might not only supply Brazil, but even the whole of the American continent with that useful metal. Several fine specimens of Brazilian native copper Copper. have been sent to Lisbon; most of them were collected in a valley near Cocheira, about fifteen leagues from Baja; one of these pieces is said to weigh two thousand six hundred and sixteen pounds. The inhabitants complain that there is little salt in this country of gold and diamonds; its scarcity Scarcity of and exorbitant price have tended to retard the improvement salt. of the colony. A quantity of salt sufficient to cure an ox, costs more than three times the price usually given for that animal; on this account, the oxen that are killed for the sake of their hides, become too often the prey of wild beasts. As this calamity must be attributed to the caprice of man, it is the more to be regretted; nature, indeed, has been bountiful to the Brazilians, plenty of sea salt might be obtained in this vast kingdom; vessels might be loaded with it at Baya, Cabofrio and other places; but individuals are prohibited from selling that article, lest they should injure the oppressive monopoly of a company. The great scarcity is most severely felt in the mining districts, the mules and other animals employed in the works do not take sufficient sustenance unless salt be mixed with their food. If agriculture has hitherto made little progress in Brazil, it must XCI. BOOK be partly attributed to the excessive duties on sait, the farmer is thus prevented from breeding cattle, for he cannot maintain them without it; an additional tax of twopence per pound is levied on salt, before it can pass into the mining districts, or in other words, it is dearest in the places in which it is most necessary. The earth is impregnated with salt in some parts of Brazil, and we are assured that a great many wild animals and immense herds of oxen flock instinctively to these plains. But this is not the only substance with which Brazil is ill sup plied, an author, a native of the country, affirms that there is no lime-stone, and that all the lime which is made from shells is of an inferior quality. The first part of this remark is incorrect, Mr. Mawe observed plenty of excellent limestone near Sorocaba in the well-wooded district of Gorosuara. That traveller was the first who observed limestone on the gold mines near Santa Rita; the adjoining hills are composed of it, and the plains are incrusted with a stratum of tufa deposited by the overflowing of rivers after heavy rains. Limestone has also been found near Sabara in Minas Geraes; a rich vein of lead ore in calcareous spar was discovered at a few leagues from the Abaité, a rivulet in Minas Novas; nitrate of potass is produced in great abundance on the extensive calcareous strata of Monte Rodrigo, between the Rio dos Velhos and the Parana.† Plants. The vegetable, as well as the mineral productions of Brazil are imperfectly known; it appears from the works of Pison and Marcgrav, that the Flora of the northern provinces resembles that of Guyana; according to the observations of a learned traveller, at present in Rio Janeiro, the same analogy extends to the southern districts; and many of the plants mentioned by Aublet are found in both countries. The most common genera are Compositæ, legumina, euphorbia and rubia Da Acunha de Coutinho, X. 7. Mawe, passim. Lettre de M. Auguste de Saint Hilaire. |