. Travels in the interior of Brazil : with notices on its climate, agriculture, commerce, population, mines, manners, and customs : and a particular account of the gold and diamond districts : including a voyage to the Rio de La Plata. iverbeing stopped just below the head of the canal byan embankment, formed of several thousand bagsof sand. This is a work of considerable magni-tude, and requires the co-operation of all the ne-groes to complete it; for, the river being wideand not very shallow, and also occasionally sub-ject to overflows, they have to make the embank-ment so strong as to resis
. Travels in the interior of Brazil : with notices on its climate, agriculture, commerce, population, mines, manners, and customs : and a particular account of the gold and diamond districts : including a voyage to the Rio de La Plata. iverbeing stopped just below the head of the canal byan embankment, formed of several thousand bagsof sand. This is a work of considerable magni-tude, and requires the co-operation of all the ne-groes to complete it; for, the river being wideand not very shallow, and also occasionally sub-ject to overflows, they have to make the embank-ment so strong as to resist the pressure of thewater, admitting it to rise four or five feet. The deeper parts of the channel of the riverare laid dry by means of large caissons or chain-pumps, worked by a water-wheel. The mud isthen carried off, and the cascalho is dug up andremoved to a convenient place for washing. Thislabor was, until lately, performed by the negroes,who carried the cascalho in gamellas on theirheads, but Dr. Camara has formed two inclinedplanes about one hundred yards in length, alongwhich carts are drawn by a large water-wheel, di-vided into two parts, the ladles or buckets of PKKAK IN ITIE HIIJL,, SKEWING IHE TOPAZ MINE AT BED THE I : DRY W £N AOQUTPIK T, TO COTT. 3H IT FOIJ DIAMOND S, GOLD, & WASHING FOR DIAMONDS. 315 which are so constructed that the rotatory motionmay be altered by changing the current of waterfrom one side to the other; this wheel, by meansof a rope made of untanned hides, works two carts,one of which descends empty on one inclined plane,while the other, loaded with cascalho, is drawn tothe top of the other inclined plane, where it falls intoa cradle, empties itself, and descends in its turn. Ata work, called Cangica, formerly of great import-ance, about a mile up the river on the opposite side,there are three cylindrical engines (wims) for draw-ing the cascalho, like those used in the miningcountry of Derbyshire, and also rail-ways oversome unev
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Keywords: ., bookcentury1800, bookidtrav, booksubjectminesandmineralresources
