58 NATURAL HISTORY OF PRECIOUS STONES, &c.
of
old Diamonds ; but the panic was speedily stayed by the Government
making the working of the mines a royal monopoly, and farming out their
produce to a single merchant so as to regulate the supply.
To
maintain the value of the Indian stones the trade (then chiefly Dutch)
set to work to persuade the public that the new comers into the market
were a spurious kind, in fact no true Diamonds at all. As late as 1750
Jeffries gravely asserts the same thing, though it is hardly possible
he was not aware of its falsity. Amongst other methods resorted to by
those in the opposite interest to establish the reputation of the thus
vilified Brazilian species, Caire mentions one repeated to him by an
ancient Venetian lapidary, able to remember so far back, which was the
cutting the new stones after Indian patterns, so as to make them pass
for old Golconda tables.
The
yield of the Brazilian washings stood at a pretty regular average of
30,000 carats (not quite 26 lbs. troj-), until 1843, when the discovery
of the Sincora mine in Bahia multiplied it twenty-fold. But
this increase that had so alarmed all possessors of diamonds only
lasted two years ; the mortality amongst the workers there, owing to
the malaria and the difficulty of getting provisions, speedily putting
a stop to the enterprise. In 1851 the yield had declined to 150,000
carats, and still keeps falling off. The Brazilian stones run very much
smaller than those formerly yielded by the Indian workings; out of
10,000 found in the Jaquinitonita, the oldest and richest in Brazil,
8000 are under one carat, and only two or three from 17 to 20 carats.
Of the entire year's produce of all the mines put together, it is
.seldom that a single one exceeds 30 carats. The slave fortunate enough
to find one of 17-1/2 carats obtains his freedom, a permission to work
on his own account, and a new suit of clothes. In the year 1851 unusual
prizes
