are
intersected by the river Paraguassu and its tributaries; it is said
that there were as many as 20,000 miners working here in 1845, and it
was estimated that 54,000 carats were produced in Bahia in 1858. The
earlier workings were in the Serra de Chapada to the N.W. of the mines
just mentioned. In 1901 there were about 5000 negroes employed in the
Bahia mines; methods were still primitive; the _cascalho_ was dug out
from the river beds or tunnelled out from the valley side, and washed
once a week in sluices of running water, where it was turned over with
the hoe, and finally washed in wooden basins and picked over by hand;
sometimes also the diamantiferous material is scooped out of the bed
of the shallow rivers by divers, and by men working under water in
caissons. It is almost exclusively in the mines of Bahia, and in
particular in the Cincora district, that the valuable carbonado is
found. The carbonado and the diamond have been traced to an extensive
hard conglomerate which occurs in the middle of the sandstone
formation. Diamonds are also mined at Salobro on the river Pardo not
far inland from the port of Canavieras in the S.E. corner of Bahia.
The enormous development of the South African mines, which supplied in
1906, about 90% of the world's produce, has thrown into the shade the
Brazilian production; but the _Bulletin_ for Feb. 1909 of the
International Bureau of American Republics gave a very confident
account of its future, under improved methods.

_South Africa._---The first discovery was made in 1867 by Dr W. G.
Atherstone, who identified as diamond a pebble obtained from a child
in a farm on the banks of the Orange river and brought by a trader to
Grahamstown; it was bought for L500 and displayed in the Paris
Exhibition of that year. In 1869 a stone weighing 83-1/2 carats was
found near the Orange river; this was purchased by the earl of Dudley
for L25,000 and became famous as the "Star of South Africa." A rush of
prospectors at once took place to the banks of the Orange and Vaal
rivers, and resulted in considerable discoveries, so that in 1870
there was a mining camp of no less than 10,000 persons on the "River
Diggings." In the River Diggings the mining was carried on in the
coarse river gravels, and by the methods of the Brazilian negroes and
of gold placer-miners. A diggers' committee limited the size of claims
to 30 ft. square,