
entirely compleated till July, 1774. They then made
the fatal difeovery, that there never exiftcd a vein, or
any appearance o f fuch in the tenth. gallery, and that
the e'vent alluded to, had been a deception, to draw
in new fubferibers to indemnify former Idles. This has
been a dear-bought experience to the French, who had
ereded cdiifiderable buildings' at the mine .; particularly
at Cazalla, where they had built large furnaces, and a
machine for grinding inferior ore, at a league and a half
diilance, On the rivulet o f Guefna. Thefe is no doubt
however that the former adventurers muft have obtained
great quantities o f Ve'fy rich mineral, as is evident 'by
the excavations from the furface, down to the fourth
■gallery, which diminiihed towards the eighth, the total
depth Of the mine being 1200 Caltilian feet. The chief
‘engineers are o f Opinion the antients had great fuccefs
down to the fourth gallery, and tha t there, as the vein
{truck off more obliquely to the South, they were deceived
by a branch o f the chief vein, which decoyed
them as far as the eighth gallery, where it finiilied ;
that from thence they proceeded at a great expence in
■quell of the vein to the tenth gallery without fuccefs,
and then gave it up.
The prefent adventurers difeovered a very rich mineral
in the eighth gallery, which at firfl appeared to run
‘a great length, but they were foon difappoirited, and only
extracted
cxtraded 4001b. o f mineral, thoughfo rich, that fome pieces
produced at the:rate pf 70 40 8o per cent, and on a medium,
have been rated at 50 per cent..fpecimens of which
wereife.nt to the court in November 1775, and are to be
feen in the royal cabinet o f natural hiitory at Madrid,
particularly one very curious fpecimen, like an incruf-
tation of rubies, called Roficlerby mineralogifts, from its
rofe-colour appearance.
The prefent workmen have abandoned the old works,
at Pozo Rico, taken away their engines, and fuffered it
to fill up, and have applied towards the North, on the
diredian of the vein from North to South, and in a
gallery Undertaken two years ago in that part, have dif-
covered appearances which flatter them with fuccefs,,
when they come to a point where feveral veins reunite, '
Their Works at Cazalla, where- they -have extraded
fome rich mineral, though in fmall quantities, deviate
from the former operations, and are upon a new plan,
propofed by Mr. Duhamel a French engineer, who gives
them great hopes, according to all principles o f the art;
but for the carrying this on, no lefs a fum is required
than 600,000 livres ; (.£25,000 iterling) the ore which
has been fmelted hitherto at the new foundery, on the
river Guefna, has only produced 4852 ounces of refined
P p 2 filver