It is well known that quicksilver unites very readily with almost all
metals, and when added in a considerable quantity forms with them a
paste which can be kneaded, and which is called amalgam. On the other
hand, as it does not unite with the earths, being a metallic substance,
it furnishes an excellent medium for separating gold and silver from
the substances with which they are found. The amalgam is squeezed
through a piece of leather, in which these precious metals remain with
a certain portion of the quicksilver; and the former are freed from the
latter by means of fire, which volatilizes the mercury. This amalgam
made with gold serves also for gilding metals (water-gilding)[28], if
it be rubbed over them, and afterwards heated till the quicksilver be
driven off.
The first use of quicksilver is commonly reckoned a Spanish invention,
discovered about the middle of the sixteenth century; but it appears
from Pliny, that the ancients were acquainted with amalgam and its use,
not only for separating gold and silver from earthy particles, but also
for gilding[29]. Vitruvius describes the manner of recovering gold from
cloth in which it has been interwoven. The cloth, he says, is to be put
into an earthen vessel, and placed over the fire, in order that it may
be burnt. The ashes are to be thrown into water, and quicksilver added
to them. The latter attracts the particles of the gold, and unites with
them. The water is then to be poured off, and the residue put into a
piece of cloth; which being squeezed with the hands, the quicksilver,
on account of its fluidity, oozes through the pores, and the gold is
left pure in a compressed mass[30]. Isidore of Seville says also, that
quicksilver is best preserved in vessels of glass, as it penetrates
all other substances; and that without it neither silver nor brass can
be gilded[31]. Modern mineralogists however have this advantage over
the ancient, that they know how to separate the quicksilver from gold
and silver without losing it. Instead of exposing the amalgam to an
open fire, as formerly, and driving off the volatile metal, it is now
put into a retort, and the quicksilver is collected in a receiver for
further use.
Those also who wash gold from the sand found near rivers, use
quicksilver before their work is completed; and I am strongly inclined
to believe that this method prevailed in Germany long before the
discovery of the mines in America. In the year 1582, John Michael
Heberer described the washing of gold as he saw it practised at
Selz, not far from Strasburg; and at that time quicksilver had been
long employed for that purpose. In Treitlinger’s Dissertation, also,
concerning the collecting of gold, and particularly in the Rhine, there
is a description of the manner in which gold sand is washed by means of
quicksilver, but no date is mentioned[32].
The history of employing mercury in procuring the American silver is,
as far as I know, most fully given by the Jesuit Acosta[33], whose
relation of the Indies abounds with curious and useful information.
The quicksilver mines of Peru are situated in an extensive ridge of
mountains near Guamanga, on the south side of Lima, and at no great
distance from it. They are called Guancabelica, or Guancavilia. The
mines were discovered about the year 1566 or 1567, when Castro was
viceroy of Peru, by Henry Garces, or Graces, as he is called by the
Portuguese. This man was a native of Porto, went to Peru in the Spanish
service, and after the death of his wife became canon of the cathedral
of Mexico. He translated the Lusiad of Camoens from the Portuguese
into Spanish, and this has procured him a place in Professor Dieze’s
translation of Velasquez’s History of Spanish Poetry. He caused a law
to be enacted that no silver bullion should be suffered to circulate
in Peru; but his greatest service was the discovery of the quicksilver
mines. As he was one day examining the red earth, which the Indians use
for paint, and call _limpi_, he observed that it was native cinnabar;
and as he knew that quicksilver was extracted from it in Europe, he
went to the place where it was dug up, made some experiments, and thus
laid a foundation for the most important works. No one however thought
of employing this metal in the silver mines till the year 1571, when
Francis de Toledo being viceroy, one Pero Fernandes de Velasco came
to Peru, and offered to refine the silver by mercury, as he had learnt
at the smelting-houses in Mexico. His proposal being accepted, and
his attempts proving successful, the old methods were abandoned, and
that of amalgamation was adopted in its stead[34]. From this account
it appears that Garces was not the inventor of amalgamation, that it
was introduced into Peru in the year 1571, and that it had been long
before practised in Mexico; but at what period it was first used there
I have not been able to learn. The abbé Raynal says, that quicksilver
was a free article of trade till the year 1571, when it was declared
to belong exclusively to the crown; and this regulation was made in
consequence of its being employed in refining. Robertson, in his
History of America, tells us that the mines of Guanacabelica were
discovered in 1563, and that amalgamation was introduced in 1574.
Anderson says, in his History of Commerce[35], that in the second
volume of Hakluyt there is a letter which shows the use of quicksilver
to have been a new invention in the year 1572. This letter I
found, not in the second, but in the third and last volume of the
Voyages collected by Hakluyt[36]. It was written in the above year
by a merchant named Henry Hawks, and contains only the following
information: “A good owner of mines must have much quicksilver; and as
for this charge of quicksilver, it is a new invention, which they find
more profitable than to fine their ore with lead.”
Gobet, in a work entitled The Ancient Mineralogists of France, accuses
Alphonso Barba of asserting that he found out amalgamation in the
year 1609. To examine this charge, it will be necessary to give some
account of the metallurgic works of that Spaniard, which, perhaps,
may not prove unacceptable to those who are fond of metallurgy and
mineralogy. Alvaro Alphonso Barba was born at Lepe, a small town in
Andalusia, and officiated many years as clergyman of the church of St.
Bernard, at Potosi. The first edition of this work was printed in
quarto, at Madrid, in 1640, in the Spanish language, and illustrated
with cuts. This book the Spaniards for a long time concealed, because
they considered it as containing all their metallurgic secrets; though
at that time there were much better works of the kind in Germany, and
though amalgamation had been long known and practised. Edward earl of
Sandwich, being ambassador to Spain, found however an opportunity of
procuring a copy of it, as a great rarity; and he began a translation
of it into English, but translated only the first two books. This
translation was published at London in octavo, in 1674, after the
earl’s death, and entitled The First Book of the Art of Metals, in
which is declared the manner of their generation, and the concomitants
of them. Written in Spanish by Albaro Alonso Barba, translated by the
earl of Sandwich. From this English edition several German translations
have been made, of which I am acquainted with the following: two
at Hamburg, one printed in 1676, and the other in 1696; and two at
Frankfort, one in 1726, and another in 1739. In the year 1749 a new
edition appeared at Vienna. This edition, which is very different from
any of the former, was translated from the French by one Godar, who was
not a German, and who on that account apologises in the preface for the
badness of his style. All these editions however are imperfect; for the
original contains five books, as we learn from Leibnitz, who caused
them to be transcribed. In the year 1751 a new translation came out
at Paris, entitled Metallurgy, or the art of extracting and purifying
metals, translated from the Spanish of Alphonso Barba, by M. Gosfort,
with the most curious dissertations on mines and metallic operations;
of this translation the celebrated abbé Lenglet de Fresnoy is said to
have been the editor[37].
To judge by two of the German editions, Gobet has done Barba an
injustice. In that of 1676, I find Barba expressly says he does not
believe the ancients were acquainted with the art of extracting silver
from pounded ore by the means of quicksilver. This certainly does not
indicate that he laid claim to the invention; besides, he everywhere
speaks of amalgamation as an art long used in America, but complains
of the negligence with which it was practised. In a passage however
in the Vienna edition, and which has probably been added by Gobet, we
are told that in the year 1609, Barba attempted to fix quicksilver,
and with that view bethought himself of mixing it with finely pounded
silver ore; that he at first imagined, with surprise, that he had
obtained a mass of silver, but that he soon perceived that the mercury
was not changed into silver, but had only attracted the particles of
that metal. “I was,” adds Barba, “highly pleased with my new discovery
of managing ore, of extracting its contents, and of refining it; and
this method I continued to practise.” I imagine that Barba was still in
Europe in 1609, and made that experiment before he was acquainted with
the smelting-works in America. I am however of opinion, that one will
see by the original that Barba did not wish to claim the invention of
amalgamation as practised in the mines of America.