XCI. impede the force of the billows or the tides. The concourse BOOK of so many great streams flowing in a contrary direction to the general course of the currents and the tides, produces the Pororoca; this extraordinary tide which is unknown. in most countries of the world, has already been described in a former part of our work. No great river enters the ocean between Para and Pernambuco, although the coast is nearly the same in appearance as that in which the Maranhao, the Rio Grande, and the Paraiba discharge themselves into the sea. These rivers are, during the rainy season, Torrents. so many torrents, which inundate the whole country; at other times their waters are absorbed by the arid soil on the inland mountains, their charnels are frequently dry, and the Indians walk along them.* No river flows into the ocean between Cape Frio and the 30th degree of south latitude. That portion of the coast is very elevated, all the streams run into the interior, and join the Parana or Uraguay, which rise from the inland mountains. The Rio Grande de San Pedro is broad near the sea, but as its course is not of great extent, its breadth must be ascribed to the lowness of the shore and the downs in the neighbourhood. In so extensive a country as Brazil, it may be readily Climate. believed that the climate is very different in distant provinces. The marshy banks of the Amazons, and the humidity of the soil near them render the heat of summer less intense. The storms and tempests on that river are as dangerous as those on the ocean. The Madeira, the Tocantins, The intethe Xingu, and the St. Francis, pass near lofty mountains, rior. or elevated plains, and the climate in their vicinity is cool and delightful. All the fruits of Europe may be brought to perfection in the country adjoining San Paulo. The healthful temperature of that city, its situation almost under the tropic of Capricorn, its height twelve thousand feet above the level of the sea give it all the charms of a tropical climate without any of the inconveniences arising from XCI. Of the northern coast, Rio Ja neiro. excessive heat. It appears from the observations of M. Muller, which are considered the most accurate, that the mean temperature throughout the year is from 22° to 23° of Reaumur. The range of the thermometer during the winter and summer months is greater there than in the northern provinces.* The west wind passes over large forests or swampy plains into the interior, and is considered unhealthy. The air, from its great heat, is sometimes filled with igneous particles, which generate too frequently dangerous diseases. The unwholesome blasts are partly corrected by the aromatic plants that abound in the woods, and their fragrance is wafted throughout the country by the western breeze. The climate of the coast between Para and Olinda is not so moist as that of Guyana, but differs little from it in other respects. The rainy season begins generally in March, but sometimes in February; and it has been proved by the observations of Marcgrav that the south-east winds prevail not only during the whole of the wet season, but a short time before and after that period. The north wind continues with little interruption during the dry months, the soil of the mountains is then parched, the plants languish or decay, the nights too are colder than at any other season; and hoar frost is not uncommon. During the rest of the year, the extreme heat of the climate is tempered along the coast by refreshing sea breezes; the fields are clad in green, and nature appears everywhere in a state of constant activity. A sharp east wind continues during part of the night and blows regularly about sunrise. The dews are as excessive as those in Guayana and the Antilles. Climate of M. Dortat concludes from observations which he himself made, that the mean temperature of Rio Janeiro during the year 1781 was 71° 65' of Fahrenheit, and that in 1782 it was 73° 89'. The rain that fell in the last of these years exceeded forty-seven inches. The greatest quanti Spix's Travels in Brazil. + Marcgrav, Hist. Nat. du Braz. Book VII. chap. 2. Memoreas, tom. I. p. 345. XCI. island of ine. ty fell in October, and the least in July. The hygrome- BOOK ter indicated the highest degree of evaporation in February, and the lowest in July. There were in the course of the same year a hundred and twelve days of cloudless weather, a hundred and thirty-three in which the sky was partly obscured by clouds, and a hundred and twenty of rain. M. Dorta adds, that there were thunder storms during seventy-seven of these days, and dense mists during fortythree. The dreadful thunder storms in these latitudes never occur in Europe, and it is difficult for us to form adequate notions of them. The observations of Dorta differ of the little from those made on the island St. Catharine by Don St. CathaPernetty, who complains chiefly of the fogs to which the island was subject in his time. "The forests," says he, "excluded the sun's rays, and perpetual mists were formed on the heights around them. The unhealthiness of the air was not much diminished by the aromatic plants, although their fragrance extended to the distance of several leagues from the land." Modern travellers, and particularly M. Krusenstern extol the cli ate and salubrity of St. Catharine's. The change must have proceeded from the cultivation of the soil, and the cutting of the woods. Mr. Mansa indeed confirms the truth of this remark, for he tells us that good timber is at present not very common on the island. The diseases to which the colonists of Brazil were sub- Diseases. ject in the time of Pison appear to be the same as those at present in Guyana; but leprosy and elephantiasis were then unknown. The maladies now most prevalent at Rio Janeiro are chronical diarrhoea, dropsy, intermitting fever, and hydrocele. In this, as in other warm climates, the augmentation of external stimulants, particularly heat and light, proves unfavourable to the health of the European; these stimulants occasion the excitement of the animal functions, and produce their consequent exhaustion. "During the day," says Dr. Von Spix, "when I was in a state of repose, my pulse beat quicker in Brazil than it usually did in Europe." Although it is ascertained that syphilis BOOK Minerals. was not known to the aborigines of America,* it is not less true that that disorder is at present very common in Rio Janeiro. The people on the banks of the Parayba are subject to goitres; but idiocy, which makes this disorder so · distressing in Switzerland, is seldom combined with it in .Brazil. We shall begin our account of the Brazilian minerals with some observations on the diamond. That precious stone is found in a stratum of rounded quartzose pebbles joined together by earthy matter of variable thickness. This covering or envelope of the diamond is termed its cascalho, and the low ground on the banks of rivers, in which it is found, is equally rich in diamonds throughout its whole extent. Many well-known places are kept in reserve, while uncertain experiments are made in different districts. The value of an unworked flat on the side of a river may be calculated from the produce of the adjoining land. Mr. Mawe heard an intendant observe, that a certain piece of ground which he would in due time work, or whenever an order arrived from government for an immediate and extraordinary supply, might yield ten thousand carats of diamonds. The substances found near diamonds, and supposed to be good indications of them, are, bright iron glance, a slaty flint-like mineral of fine texture, resembling Lydian stone, black oxide of iron in great quantities, round pieces of blue quartz, yellow crystal and other minerals entirely different from those on the adjacent mountains. It is not only along the banks of rivers that the Brazilians seek for the diamonds; they have been found in cavities and water courses on the summits of the most lofty mountains.+ It has been supposed that the diamonds of Brazil are not so hard as those from the East Indies, and also that the form of the latter resembles an octahedron, and that of the Spix's Travels. Humboldt's Essay on New Spain. former a duodecahedron. But these distinctions are disre- BOOK garded by the celebrated Haüy. Lapidaries and jewellers XeI. believe that the eastern diamonds are of a finer water, and more valuable than those from Brazil. The district of Cerro do Frio consists of rugged mountains extending in a northerly direction, which are generally considered the highest in Brazil. That part termed the diamond district, is about sixteen leagues from Diamond north to south, and about eight from east to west. It was district. explored, for the first time, by some enterprising miners of Villa di Principe. These men went solely in quest of gold without suspecting that there were any precious stones in the rivulets. Some diamonds, however, were collected during their excursions and afterwards given to the governor of Villa di Principe, who declared them to be curious bright crystals, and used them as card count ers. A few of these uncommon pebbles, for that was the name by which they were called, were brought to Lisbon, and put into the hands of the Dutch Consul, who received instructions to send them to Holland, then the principal mart in Europe for precious stones. The lapidaries in that country knew their real value, and their right name; and the Consul managed matters so well, that a commercial treaty was concluded between the two states a short time after the king was informed that diamonds had been found in his Brazilian possessions. The weight of these precious stones imported into Europe during the first twenty years subsequent to their discovery, is said to have exceeded a thousand ounces. Such a supply did not fail to diminish their value; many of them were sent to India, the only country from which they had been formerly exported, and obtained a better market there than in Europe. Cerro do Frio has few attractions for settlers; there are no wood and even no plants in many parts of it; sterile mountains and desert plains convince the traveller that he is in the diamond district.* From the year 1801 to 1806, the expenses *Mawe's Travels in Brazil, |