ordinary violence, it is eyident, that if, in this mixture,
there had been the leaft grain of quickfilver, it would ne-
celfarily rarify and condenfe againft thefides of the moift-
ened veifel. In effe<ft, we did obferve fome mercury
there, but in ib fmall a degree, that it was hardly perceptible
with a lens, and of courfe o f no confequence ;
for in every fufion o f ores, fojne minute particles will
efcape in the fcoria.
To difcover if any grains of mercury were loft in the
.air, I placed four large copper veffels, not tinned, in
four different places, one on the eight inches of earth,
which covered the furnace, whofe aperture is about three
feet and a half diameter, others on the firft aludels,
which are the hotteft, another at the obtufe angle o f the
fame, where the mercury condenfes, and the other at the
higheft part o f the chimney, in the chamber, where
the aludels lead to ; as it is known,» with what quick-
nefs mercury unites to all metals, except iron, if it
exhaled at any of thefe places, where the copper veffels
were fixed, it would have appeared on the copper, for
I left them there above twelve hours, at the expiration
o f which, not the leaft particle of mercury appeared.
In the precincls of Almaden, there are twelve furnaces,
called The Twelve Apoftles; each can receive about
bout 200 quintals, including good and bad ftone, which
in three days will produce about 40 quintals o f quickfilver.
Three days more are required to repair the fur-
nace, and replace every thing properly, fo that four out o f
the twelve, are always in action, the violent heats o f the
fummer excepted, when a fufpenfion from labour is unavoidable.
When we refled on the advantages o f thefe furnaces,
they mult be confidered as objeds o f the greateft utility
and honour to Spain, foreigners having likewife improved
from them- The Hungarians have imitated them
in their mines, by which they have confiderably reduced
the number of workmen, employed in the old method,
with retorts. Foreigners are ihewn every thing without
referve(a), and are permitted to examine the rocks at
their leifure, and even make drafts o f the furnaces, and
fee their method o f packing-up the quickfilver in goat-
ikins, which is certainly the beft policy, to facilitate the
[a) Mr. 'Ferber, in his travels through Italy, fpeaking o f the quickfilver mines o f Idria, in
Friul, belonging to.the houfe of Auftria, fays, J‘ They confider here their common melting
and uftulation of the mercurial ores, as an arcanum, and accordingly do not allow any ftranger
to examine their fubliraation houfe, though even its exterior form undoubtedly, and at firft
fight, proves their method being the very fame as that which is ufed at Almaden, in Spain,
and has been very minutely defcribed by Mr. Juflieu, in the memoirs o f the French academy;
this method is far from being perfeit, and above any improvements, but probably they do
not think fo, elfe there could be no poffible reaibn for this myftery in fo common a manipulation
: nothing is more oppofite to the progrefs o f fcience, and even to the mtereft o f
ftates, than fo fingular areferve.” Travels through Italy in 17 71 and 17 7 2, by John Jamfes
Ferber. London,. 17 76.
operations