ot) that varied from
1,288 francs per year in 1734 to 1,344 francs for the last contract, that
ended in 1772. At this epoch the government took the exploitation of the
diamond in hand, and gave it in charge of a special administration, which
was submitted to the direction of the treasury of Lisbon, and which had at
its head a comptroller. This new regime lasted till 1845. In order to
render the surveillance of the treasury agents efficient, and prevent
smuggling (which can be so easily done with an object like the diamond),
it was necessary to impose a special regime over the entire region of
Diamantina, and, in fact, the latter was, up to the independence of
Brazil, submitted to Draconian regulations.

[Illustration: FIG. 1.--DAM ON THE RIBEIRAO INFERNO AT PORTATO DE FERRO.]

We only know the quantity of stones that were discovered during the period
when operations were directed by the Royale Extraccao, from 1772 to 1845,
and this was 269,870 grammes, or more than 1,300,000 carats. It should be
understood that what was taken by stealth does not enter into this total,
and it must be stated that during the latter years, when the Extraccao
existed only in name, smuggling must have been active.

[Illustration: FIG. 2.--ARRANGEMENT OF THE MACHINERY AT THE PORTATO DE
FERRO DIAMOND DEPOSITS.]

Since that epoch the exploitation has been continued by lessees of the
diamondiferous grounds. It is almost impossible to estimate what the
territory has produced. The discovery of the Cape deposits has given it a
terrible blow. Although the Brazilian diamond is much more beautiful, and
for this reason is held at a much higher price, these new exploitations,
by annually throwing large quantities of stones upon the market, have led
to a great reduction in the price, and the Diamantina exploitations, which
have become long, difficult, and costly, have received a serious set-back.
So the annual production of this region, which was estimated for the years
preceding 1870 at 3,000 oitavas (about 52,000 carats), is now scarcely
500.

The rivers in the environs of Diamantina rim at the bottom of deep and
narrow gorges that have been scooped out to depths of 300 or 400 meters
through the denuded plateau in whose center stands the city of Diamantina.
In the bed of these rivers, in places where they have not yet been worked,
there may be found, underneath a stratum of modern sand, another of rocks,
and finally a diamondiferous deposit of round