De Re Metallica, Translated from the First Latin Edition of 1556 by Georg Agricola
1545. He states that refining silver with mercury was introduced at
1611 words | Chapter 19
Potosi by Pedro Fernandes de Velasco from Mexico in 1571, and states
(Grimston's Trans., Vol. I, p. 219): "... They put the powder of the
metall into the vessels upon furnaces, whereas they anoint it and
mortifie it with brine, putting to every fiftie quintalles of powder
five quintalles of salt. And this they do for that the salt separates
the earth and filth, to the end the quicksilver may the more easily draw
the silver unto it. After, they put quicksilver into a piece of holland
and presse it out upon the metall, which goes forth like a dewe, alwaies
turning and stirring the metall, to the end it may be well incorporate.
Before the invention of these furnaces of fire, they did often mingle
their metall with quicksilver in great troughes, letting it settle some
daies, and did then mix it and stirre it againe, until they thought all
the quicksilver were well incorporate with the silver, the which
continued twentie daies and more, and at least nine daies." Frequent
mention of the different methods of silver amalgamation is made by the
Spanish writers subsequent to this time, the best account being that of
Alonso Barba, a priest. Barba was a native of Lepe, in Andalusia, and
followed his calling at various places in Peru from about 1600 to about
1630, and at one time held the Curacy of St. Bernard at Potosi. In 1640
he published at Madrid his _Arte de los Metales_, etc., in five books.
The first two books of this work were translated into English by the
Earl of Sandwich, and published in London in 1674, under the title "The
First Book of the Art of Metals." This translation is equally wretched
with those in French and German, as might be expected from the
translators' total lack of technical understanding. Among the methods of
silver amalgamation described by Barba is one which, upon later
"discovery" at Virginia City, is now known as the "Washoe Process." None
of the Spanish writers, so far as we know, make reference to
Biringuccio's account, and the question arises whether the Patio Process
was an importation from Europe or whether it was re-invented in Mexico.
While there is no direct evidence on the point, the presumption is in
favour of the former.
The general introduction of the amalgamation of silver ores into Central
Europe seems to have been very slow, and over 200 years elapsed after
its adoption in Peru and Mexico before it received serious attention by
the German Metallurgists. Ignaz Elder v. Born was the first to establish
the process effectually in Europe, he having in 1784 erected a
"quick-mill" at Glasshutte, near Shemnitz. He published an elaborate
account of a process which he claimed as his own, under the title _Ueber
das Anquicken der Gold und Silberhaeltigen Erze_, Vienna, 1786. The only
thing new in his process seems to have been mechanical agitation.
According to Born, a Spaniard named Don Juan de Corduba, in the year
1588, applied to the Court at Vienna offering to extract silver from
ores with mercury. Various tests were carried out under the celebrated
Lazarus Erckern, and although it appears that some vitriol and salt were
used, the trials apparently failed, for Erckern concluded his report
with the advice: "That their Lordships should not suffer any more
expense to be thrown away upon this experiment." Born's work was
translated into English by R. E. Raspe, under the title--"Baron Inigo
Born's New Process of Amalgamation, etc.," London, 1791. Some interest
attaches to Raspe, in that he was not only the author of "Baron
Munchausen," but was also the villain in Scott's "Antiquary." Raspe was
a German Professor at Cassel, who fled to England to avoid arrest for
theft. He worked at various mines in Cornwall, and in 1791 involved Sir
John Sinclair in a fruitless mine, but disappeared before that was
known. The incident was finally used by Sir Walter Scott in this novel.
[13] _Aurum in ea remanet purum_. This same error of assuming squeezed
amalgam to be pure gold occurs in Pliny; see previous footnote.
[14] George, Duke of Saxony, surnamed "The Bearded," was born 1471, and
died 1539. He was chiefly known for his bitter opposition to the
Reformation.
[15] The Julian Alps are a section east of the Carnic Alps and lie north
of Trieste. The term Rhaetian Alps is applied to that section along the
Swiss Italian Boundary, about north of Lake Como.
[16] Ancient Lusitania comprised Portugal and some neighbouring portions
of Spain.
[17] Colchis, the traditional land of the Golden Fleece, lay between the
Caucasus on the north, Armenia on the south, and the Black Sea on the
west. If Agricola's account of the metallurgical purpose of the fleece
is correct, then Jason must have had real cause for complaint as to the
tangible results of his expedition. The fact that we hear nothing of the
fleece after the day it was taken from the dragon would thus support
Agricola's theory. Tons of ink have been expended during the past thirty
centuries in explanations of what the fleece really was. These
explanations range through the supernatural and metallurgical, but more
recent writers have endeavoured to construct the journey of the
Argonauts into an epic of the development of the Greek trade in gold
with the Euxine. We will not attempt to traverse them from a
metallurgical point of view further than to maintain that Agricola's
explanation is as probable and equally as ingenious as any other,
although Strabo (XI, 2, 19.) gives much the same view long before.
Alluvial mining--gold washing--being as old as the first glimmer of
civilization, it is referred to, directly or indirectly, by a great
majority of ancient writers, poets, historians, geographers, and
naturalists. Early Egyptian inscriptions often refer to this industry,
but from the point of view of technical methods the description by Pliny
is practically the only one of interest, and in Pliny's chapter on the
subject, alluvial is badly confused with vein mining. This passage
(XXXIII, 21) is as follows: "Gold is found in the world in three ways,
to say nothing of that found in India by the ants, and in Scythia by the
Griffins. The first is as gold dust found in streams, as, for instance,
in the Tagus in Spain, in the Padus in Italy, in the Hebrus in Thracia,
in the Pactolus in Asia, and in the Ganges in India; indeed, there is no
gold found more perfect than this, as the current polishes it thoroughly
by attrition.... Others by equal labour and greater expense bring rivers
from the mountain heights, often a hundred miles, for the purpose of
washing this debris. The ditches thus made are called _corrugi_, from
our word _corrivatio_, I suppose; and these entail a thousand fresh
labours. The fall must be steep, that the water may rush down from very
high places, rather than flow gently. The ditches across the valleys are
joined by aqueducts, and in other places, impassable rocks have to be
cut away and forced to make room for troughs of hollowed-out logs. Those
who cut the rocks are suspended by ropes, so that to those who watch
them from a distance, the workmen seem not so much beasts as birds.
Hanging thus, they take the levels and trace the lines which the ditch
is to take; and thus, where there is no place for man's footstep,
streams are dragged by men. The water is vitiated for washing if the
current of the stream carries mud with it. This kind of earth is called
_urium_, hence these ditches are laid out to carry the water over beds
of pebbles to avoid this _urium_. When they have reached the head of the
fall, at the top of the mountain, reservoirs are excavated a couple of
hundred feet long and wide, and about ten feet deep. In these reservoirs
there are generally five gates left, about three feet square, so that
when the reservoir is full, the gates are opened, and the torrent bursts
forth with such violence that the rocks are hurled along. When they have
reached the plain there is yet more labour. Trenches called _agogae_ are
dug for the flow of the water. The bottoms of these are spread at
regular intervals with _ulex_ to catch the gold. This _ulex_ is similar
to rosemary, rough and prickly. The sides, too, are closed in with
planks and are suspended when crossing precipitous spots. The earth is
carried to the sea and thus the shattered mountain is washed away and
scattered; and this deposition of the earth in the sea has extended the
shore of Spain.... The gold procured from _arrugiae_ does not require to
be melted, but is already pure gold. It is found in lumps, in shafts as
well, sometimes even exceeding ten _librae_ in weight. These lumps are
called _palagae_ and _palacurnae_, while the small grains are called
_baluce_. The Ulex is dried and burnt and the ashes are washed on a bed
of grassy turf in order that the gold may settle thereon."
[19] _Carbunculus Carchedonius_--Carthaginian carbuncle. The German is
given by Agricola in the _Interpretatio_ as _granat_, _i.e._, garnet.
[20] As the concentration of crushed tin ore has been exhaustively
treated of already, the descriptions from here on probably refer
entirely to alluvial tin.
[21] From a metallurgical point of view all of these operations are
roasting. Even to-day, however, the expression "burning" tin is in use
in some parts of Cornwall, and in former times it was general.
[22] There can be no doubt that these are mattes, as will develop in
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