WalsJi's A''otices of Brazil. 185 



large as a grain of small shot. In this state a magnet was passed through 

 it, to which the particles of iron still mixed with the gold, adhered; and 

 this was continued till the whole was abstracted. 



" Sometimes a more scientitic process is resorted to. The mixture of dust 

 is put into a bowl, and two ounces of mercury added to two pounds of gold 

 and oxyde. Tiiis mass is worked by the hands, into a dough, when the 

 mercury takes up the gold only, which is merely entangled, but not amalga- 

 mated, with it. It is then put into a cloth, and a portion of the mercury 

 squeezed out; the remainder is set in a brass vessel, over a fire, and covered 

 with green leaves, which are removed as they become parched. They ex- 

 hibit small globules of the sublimed mercury on the surface. What remains 

 in the vessel is pure gold, changed hi colour to a dull white." 



" Our wav next morning lay along the edge of one of the most extensive 

 and richest lavras in the country, and from which the place derived its name 

 of dourado or golden. Immediately outside the village is a very large and 

 deep ravine, extending to a considerable distance, and exposing its bowels 

 stained with bright red ochre. This is excavated in soft sand stone, of the 

 consistence of hard clay, and is strongly impregnated with gold, which 

 accumulates in caldeiros, or pits like caldrons. Large masses of gold are 

 sometimes found in these caldeiros. They are indicated by fibres ramifying 

 through the jnatrix in which they lie; and when pursued from diffi;rent direc- 

 tions, they terminate in a common nucleus. A lump was found about thirty 

 years ago in this place, which weighed forty pounds." — Vol. 2. ch. 5. 



" A large topaz mine, of which our host was the proprietor, lay about a 

 mile from the zancho, and the next morning we visited it. The regions through 

 which we had passed, were generally clay mountains, or granite ridges ; we 

 had now entered a new formation, a soft schist of talk, clay, or mica slate, 

 which every where presented its lamellated edges in the ridges, just above 

 the soil. In some places it was hard and solid, as building slate ; in others, 

 it was soft and friable, and in various states of decomposition. About fifty 

 years ago, in pushing a road through one of these soft schistic knolls, which 

 stood in their way, they were astonished to see several crystals of topaz 

 tumble out of the soft mass. On this discovery they began to search, and 

 they have now found and opened three large mines in the neighbourhood, 

 within a circle of ten or twelve miles. The mine of Capao do lana, is an 

 immense circular quarry, the shape of a hollow inverted cone, whose upper 

 circumference is a mile or more. The sloping sides are composed of talk, 

 or mica slate, either green, grey, or blue, and in a state of such decomposi- 

 tion, as to be quite soft, hardly retainmg any of its lamellated structure. 

 This is called the corpo da formacao, or the substance in which the topaz 

 veins are formed. These veins are a white medullary mass, called massa 

 branca, resembling soft chalk, though not calcareous, but is supposed to be 

 some modification of mica. It form? cords as thick as an arm or leg, running 

 for several yards, and ramifying into various smaller branches. This massa 

 branca, is the matrix in which the topaz is imbedded, like a nodule of flint in 

 a lump of chalk. 



"Here a number of negroes, with rude knives like peices of iron hoop, 

 were scarifying the ground. When they cut across a white vein, it imme- 

 diately became visible,and they pursued it, dislodging the topazes which were 

 bedded msidc, and handmg them to an overseer with a bag." — Vol. ii. ch. 7. 



" In tJie course of my journey I passed over six different surfaces, strikingly 

 distinguished from each other in their aspect, formation, and productions. 

 The first was the Beiramar, the rich plain which extended from the edge of 

 the sea, to the base of the great serra, generally about sixty miles in breadth. 

 This is, with some exceptions, a flat surface, witii an alluvial or sandy soil, 



Vol. \.—.li 



