river
and its tributaries, and some think that the whole region, back to the
Pardo and Jequetinhonha rivers, has an understratum of the
diamondiferous deposit. Several French and English companies have
worked these Salobro mines for years at a profit.
Authorities
conflict regarding the output of the Brazilian mines in the early years
after their discovery. Up to 1740 estimates of the yearly production
vary from 20,000 to 144,000 carats. From 1740 to 1772 the official
reports gave an average production of about 52,000 carats per annum.
Then
the government began to work the mines, much after the same methods
pursued by the lessees, but guarding the diamondiferous districts with
soldiers, to prevent ingress or egress of any not employed or properly
accredited, and to arrest smugglers. The inhabitants even could not
cross the line without a written permit, and everybody on leaving the
diamond district was searched. If a smuggler was caught, his property
was confiscated and he was sentenced to imprisonment, the soldier being
rewarded. Notwithstanding the utmost watchfulness, smuggling was
practiced on a large scale, probably with some connivance on the part
of officials, and the contraband stones were usually above the average
in size and quality. The cost of operation to the government was
excessively high. For several years four to five thousand negroes were
employed, but the number dwindled by 1808 to about one thousand. From
1772 to 1818, while the mines were under government administration,
they are said to have yielded 1,298,037 carats, the best year being
1784, with an output of 56,-145 carats, and the poorest 1818, with a
production of
