The recovery of copper from vitriolated waters, from De Re Metallica, 1556, by Agricola (Georg Bauer). |
Take some iron sheets and lay them in vitriol
water, being immersed in that, they will rust. Scrape off this rust, which will
be a red powder, melt it in a crucible, and you will have perfect copper. The
same effect can be had from various waters that are naturally vitriolated,
because they flow through mines of vitriol, such as those of a source some
distance from Leiden , and
another below the fortress of Smolnik, [now in Slovakia ].
Vitriol is an acidic sulfate dissolved in water,
it could be made in the laboratory, but it also occurred naturally around
mining operations where sulfurous minerals were present. Alchemists knew this
solution as "oil of vitriol" and "spirit of vitriol." The mine that Neri references
in Smolnik became famous for transmutation. As late as the eighteenth century,
scientists and experimenters from around Europe made the pilgrimage to see the effect for
themselves and tried to figure out what was happening. It may be a surprise to
some readers, but following the above instructions will, in fact, produce
copper just as Neri claimed. There is no deception or sleight of hand involved;
the explanation is straightforward, but first, Neri treats us to a rare glimpse
of his own reasoning on the subject:
Some estimate and not without reason, that this
experiment, being used to prove the transmutation of metals, is not suitable
for this purpose. They say that the vitriolated waters become such because they
are already heavy with the corrosive spirits of sulfur, having passed through
the copper or iron mine, these waters corrode copper in the same way aqua
fortis corrodes silver. So that really the substance of the copper remains in
the water, which attacks the surface of the iron, which always remains iron.
However, if that were true then the iron would not get consumed, or if it were
consumed it would mix with the substance of the corroded copper in the water,
and if it were fused, it would remain a mixture of iron and copper. And yet in
this experiment, all the iron is consumed; it is reduced by the vitriolated
water into powder, […] which in the fusion is still pure copper, so there
should remain no doubt that this is a true transmutation.
Given the state of chemistry at the time, Neri's
reasoning is clear and rational. The iron disappears and a copper coating
materializes in its place. What better evidence of transmutation could one ask
for?
The key to what was actually happening is in
the criticism leveled by skeptics. It turns out that they were on the right
track, but neither they nor Neri had the full picture. Today, we understand it
as a simple ion exchange reaction; blue vitriol water is a transparent
saturated solution of copper sulfate (CuSO4), in the presence of
solid iron, the liquid dissolves the iron; copper from the vitriol is deposited
in its place. The two metals, copper and iron, change places: the iron
dissolves, forming green vitriol (FeSO4) and copper is expelled from
the solution. The result is a reduction in the amount of the iron, which is
replaced by a proportional deposit of pure copper.
On a physical level, this
chemical reaction is no different today than it was in the seventeenth century.
What has changed is our interpretation of the experiment. What Neri viewed as a
transformation of iron into copper, we now see as an exchange. There is,
however, a deeper lesson in all this. As an alchemist, Antonio Neri was not
being delusional or dishonest; he was careful, observant and applied his knowledge
as best he could. This is no different from the way science works today. Both
then and now, to be successful in unraveling nature’s secrets, one must become
accustomed to a very uncomfortable situation: In the past, careful reasoning by
brilliant thinkers has led to utterly wrong conclusions. The fact that much of
our world is a mystery is unsettling; that the very process we use to understand
it can be so flawed is harder to accept. Even more difficult is that the
faculty we all rely on for survival—our own wits—can lead us so far astray.
For more, see Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, M.G. Grazzini / Nuncius 27 (2012)
For more, see Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, M.G. Grazzini / Nuncius 27 (2012)