German name he is at liberty to call it cinereum, just as the Romans called the third genus nigrum. Although
tin may never be found as a metal with its true color the black pebbles
from which it is smelted differ from it only in color.15 Galena (galena) is sometimes found with so little stone that it is almost pure lead.16
Bismuth
is recovered from the ore of a mine at Schneeberg named Bisemutaria. It
is common in silver mines. It often escapes the notice of the unskilled
miners or anyone who does not look for it carefully. On the other hand
a man may think he has been mining argentite when actually he has mined
bismuth. Sometimes it contains silver and this material should not be
thrown aside. When silver is removed from it the bismuth is entirely
consumed in the fire. When not pure it is found in three forms. It may
occur in large masses, in small masses with a black luster, and in thin
sheets on stones, marbles or rocks. Even though we do not find
metallic bismuth the ores from which we recover it come closer to it
in color than is the case with the other two metals.17
15 This refers to the tin oxide mineral, cassiterite, that contains seventy-nine per cent tin.
16 Galena, lead sulphide, contains 86.6% lead.
17 Agricola makes the following reference to bismuth in Bermannus, page 446,-Bermannus. "Before leaving this place I wish to call your attention to a certain
genus that belongs to the metals and which, I believe, was unknown to the Ancients. Our miners call it bisemutum.
Naevius. "Then you believe that there are more than the commonly accepted seven genera of metals?
Bermannus. "I am of the opinion that there are more for this metal our miners call bisemutum you
cannot correctly call either tin or lead since it differs from both and
is therefore a third metal. I will not mention the other ways in which
it differs from these two since you can see that tin is whiter and lead
darker.
Naevius. "We see that it is similar in color to galena.
Ancon. "How then can one distinguish bismuth from galena?
Bermannus.
"Easily. When you handle it, it discolors the hands unless it is quite
dense. The dense material is not as friable as galena but is sectile.
It is somewhat blacker than a genus of silver mineral which we have
said is almost the color of lead and hence can be distinguished from
these two. It often contains some silver. Wherever it is found it
indicates that silver occurs beneath it and for this reason our miners
are accustomed to call it the 'roof of silver.' It is commonly roasted
and from the richer portions they produce a metal, from the poorer, a
pigment that has some value.
Naevius. "Can they make vessels from this metal as they do from the other two?
Bermannus. "They can. They make very fine goblets by adding a certain quantity of bismuth to tin.
Ancon.
"Certainly among the Arabs whose alchemists, at different times, were
the most diligent of all in imitating the Greeks, I know that no
mention was ever made of this metal. For that reason I am convinced
that it is to be found in very few places.
Bermannus.
"If the alchemists, especially Greek and Arab, have not mentioned it
among the six substances they recognized nor among the spirits or
inanimate objects, I would not expect to find it mentioned in the
writings of the older philosophers or doctors."
