dence
of the extensive search made for gold. The banks are everywhere
furrowed and the vegetable mould has been entirely removed. Nothing
remains but the red dirt, cut into squares by channels divided by
narrow ridges. These channels were used for washing gravel, and were
cut on an inclined plane. The water was introduced at the head of
them, the dirt was then thrown in, and the lighter particles of clay
were washed away, while the gold remained behind.*
The
first placers in the country were called " cata." The surface dirt
which contained gold was mined until the " cascalho," or cement-gravel,
was reached. This was broken up by pickaxes, brought to the river, and
washed. The first improvement introduced was to conduct the water to
the ground and wash the gravel on the spot. These works were called "
lavras," and hundreds of them were to be seen on the banks of the Rio
das Mortes. A more improved method was practised subsequently.
In
some districts water-wheels were used to assist in the drainage of the
excavations, but were found so unmanageable that they were thrown
aside, and the negroes were employed to pack off the gravel and rubbish
on their heads in small casks.f
According
to Dr. Soetbeer, from 1691 to 1875 (one hundred and eighty-five years)
the gold production of Brazil amounted to 2,281,510 pounds Troy. By far
the greater part was derived from alluvial deposits by river-washing.
Hartt * is of the opinion that there are still extensive surface
deposits which, with modern appliances, can be worked successfully on a
large scale, and limited washings now occur in almost every province in
the empire.
Chili.—Chili
contains numerous auriferous deposits, which, according to
Schmidtmeyer, extend over most of the coast. The principal deposits are
those near Copiapo,
f Walsh, vol. ii. p. 105.
A Ibid,, pp. 112, 113.
" Geological and Physical Geography of Brazil."
