Book XI

BOOK XI.
Different methods of parting gold from silver,
and, on the other hand, silver from gold, were dis−
cussed in the last book; also the separation of copper
from the latter, and further, of lead from gold as
well as from silver; and, lastly, the methods for
refining the two precious metals. Now I will speak
of the methods by which silver must be separated
from copper, and likewise from iron. 1
The officina, or the building necessary for the
purposes and use of those who separate silver from copper, is constructed
in this manner. First, four long walls are built, of which the first, which
is parallel with the bank of a stream, and the second, are both two hundred and
sixty−four feet long. The second, however, stops at one hundred and fifty−one
feet, and after, as it were, a break for a length of twenty−four feet, it continues
again until it is of a length equal to the first wall. The third wall is one
hundred and twenty feet long, starting at a point opposite the sixty−seventh
foot of the other walls, and reaching to their one hundred and eighty−sixth foot.
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The fourth wall is one hundred and fifty−one feet long. The height of each of
these walls, and likewise of the other two and of the transverse walls, of
which I will speak later on, is ten feet, and the thickness two feet and as
many palms. The second long wall only is built fifteen feet high, because
of the furnaces which must be built against it. The first long wall is distant
fifteen feet from the second, and the third is distant the same number of feet
from the fourth, but the second is distant thirty−nine feet from the third.
Then transverse walls are built, the first of which leads from the beginning
of the first long wall to the beginning of the second long wall; and the second
transverse wall from the beginning of the second long wall to the beginning of
the fourth long wall, for the third long wall does not reach so far. Then from
the beginning of the third long wall are built two wallsthe one to the
sixty−seventh foot of the second long wall, the other to the same point in
the fourth long wall. The fifth transverse wall is built at a distance of ten
feet from the fourth transverse wall toward the second transverse wall;
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SIX LONG WALLS: ATHE FIRST. BTHE FIRST PART OF THE SECOND. CTHE
FURTHER PART OF THE SECOND. DTHE THIRD. ETHE FOURTH. FTHE FIFTH.
GTHE SIXTH. FOURTEEN TRANSVERSE WALLS: HTHE FIRST. ITHE SECOND.
KTHE THIRD. LTHE FOURTH. MTHE FIFTH. NTHE SIXTH. OTHE SEVENTH.
PTHE EIGHTH. OTHE NINTH. RTHE TENTH. STHE ELEVENTH. TTHE
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it is twenty feet long, and starts from the fourth long wall. The sixth
transverse wall is built also from the fourth long wall, at a point distant
thirty feet from the fourth transverse wall, and it extends as far as the back
of the third long wall. The seventh transverse wall is constructed from
the second long wall, where this first leaves off, to the third long wall; and
from the back of the third long wall the eighth transverse wall is built,
extending to the end of the fourth long wall. Then the fifth long wall is built
from the seventh transverse wall, starting at a point nineteen feet from the
second long wall; it is one hundred and nine feet in length; and at a point
twenty−four feet along it, the ninth transverse wall is carried to the third end
of the second long wall, where that begins again. The tenth transverse wall is
built from the end of the fifth long wall, and leads to the further end of the
second long wall; and from there the eleventh transverse wall leads to the
further end of the first long wall. Behind the fifth long wall, and five feet
toward the third long wall, the sixth long wall is built, leading from the
seventh transverse wall; its length is thirty−five feet, and from its further
end the twelfth transverse wall is built to the third long wall, and from it the
thirteenth transverse wall is built to the fifth long wall. The fourteenth
transverse wall divides into equal parts the space which lies between the
seventh transverse wall and the twelfth.
The length, height, breadth, and position of the walls are as above.
Their archways, doors, and openings are made at the same time that the walls
are built. The size of these and the way they are made will be much better
understood hereafter. I will now speak of the furnace hoods and of the roofs.
The first side 2 of the hood stands on the second long wall, and is similar in
every respect to those whose structure I explained in Book IX, when I
described the works in whose furnaces are smelted the ores of gold, silver,
and copper. From this side of the hood a roof, which consists of burnt tiles,
extends to the first long wall; and this part of the building contains the
bellows, the machinery for compressing them, and the instruments for
inflating them. In the middle space, which is situated between the second
and third transverse walls, an upright post eight feet high and two feet thick
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and wide, is erected on a rock foundation, and is distant thirteen feet from
the second long wall. On that upright post, and in the second transverse
wall, which has at that point a square hole two feet high and wide, is placed
a beam thirty−four feet and a palm long. Another beam, of the same length,
width, and thickness, is fixed on the same upright post and in the third
transverse wall. The heads of those two beams, where they meet, are joined
together with iron staples. In a similar manner another post is erected, at a
distance of ten feet from the first upright post in the direction of the fourth
wall, and two beams are laid upon it and into the same walls in a similar
way to those I have just now described. On these two beams and on the
fourth long wall are fixed seventeen cross−beams, forty−three feet and three
palms long, a foot wide, and three palms thick; the first of these is laid upon
the second transverse wall, the last lies along the third and fourth transverse
walls; the rest are set in the space between them. These cross−beams are
three feet apart one from the other.
In the ends of these cross−beams, facing the second long wall, are mortised
the ends of the same number of rafters reaching to those timbers which
stand upright on the second long wall, and in this manner is made the inclined
side of the hood in a similar way to the one described in Book IX. To prevent
this from falling toward the vertical wall of the hood, there are iron rods
securing it, but only a few, because the four brick chimneys which have
to be built in that space partly support it. Twelve feet back are likewise
mortised into the cross−beams, which lie upon the two longitudinal beams
and the fourth long wall, the lower ends of as many rafters, whose upper ends
are mortised into the upper ends of an equal number of similar rafters, whose
lower ends are mortised to the ends of the beams at the fourth long wall.
From the first set of rafters 4 to the second set of rafters is a distance of twelve
feet, in order that a gutter may be well placed in the middle space. Between
these two are again erected two sets of rafters, the lower ends of which are like−
wise mortised into the beams, which lie on the two longitudinal beams and the
fourth long wall, and are interdistant a cubit. The upper ends of the ones
fifteen feet long rest on the backs of the rafters of the first set; the ends of the
others, which are eighteen feet long, rest on the backs of the rafters of the
second set, which are longer; in this manner, in the middle of the rafters, is
a sub−structure. Upon each alternate cross−beam which is placed upon the
two longitudinal beams and the fourth long wall is erected an upright post,
and that it may be sufficiently firm it is strengthened by means of a slanting
timber. Upon these posts is laid a long beam, upon which rests one set of
middle rafters. In a similar manner the other set of middle rafters rests on a
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long beam which is placed upon other posts. Besides this, two feet above
every cross−beam, which is placed on the two longitudinal beams and the
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fourth long wall, is placed a tie−beam which reaches from the first set of
middle rafters to the second set of middle rafters; upon the tie−beams is
placed a gutter hollowed out from a tree. Then from the back of each of
the first set of middle rafters a beam six feet long reaches almost to the gutter;
to the lower end of this beam is attached a piece of wood two feet long;
this is repeated with each rafter of the first set of middle rafters. Similarly
from the back of each rafter of the second set of middle rafters a little beam,
seven feet long, reaches almost to the gutter; to the lower end of it
is likewise attached a short piece of wood; this is repeated on each rafter
of the second set of middle rafters. Then in the upper part, to the first and
second sets of principal rafters are fastened long boards, upon which are
fixed the burnt tiles; and in the same manner, in the middle part, they are
fastened to the first and second sets of middle rafters, and at the lower part to
the little beams which reach from each rafter of the first and second set of
middle rafters almost to the gutter; and, finally, to the little boards fastened
to the short pieces of wood are fixed shingles of pinewood extending into the
gutter, so that the violent rain or melted snow may not penetrate into the
building. The substructures in the interior which support the second set of
rafters, and those on the opposite side which support the third, being not
unusual, I need not explain.
In that part of the building against the second long wall are the
furnaces, in which exhausted liquation cakes which have already been
"dried" are smelted, that they may recover once again the appearance
and colour of copper, inasmuch as they really are copper. The remainder
of the room is occupied by the passage which leads from the door to the
furnaces, together with two other furnaces, in one of which the whole cakes
of copper are heated, and in the other the exhausted liquation cakes are
"dried" by the heat of the fire.
Likewise, in the room between the third and seventh 5 transverse walls,
two posts are erected on rock foundation; both of them are eight feet high
and two feet wide and thick. The one is at a distance of thirteen feet from
the second long wall; the other at the same distance from the third long wall;
there is a distance of thirteen feet between them. Upon these two posts and
upon the third transverse wall are laid two longitudinal beams, forty−one feet
and one palm long, and two feet wide and thick. Two other beams of the
same length, width, and thickness are laid upon the upright posts and upon
the seventh transverse wall, and the heads of the two long beams, where they
meet, are joined with iron staples. On these longitudinal beams are again
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placed twenty−one transverse beams, thirteen feet long, a foot wide, and three
palms thick, of which the first is set on the third transverse wall, and the last
on the seventh transverse wall; the rest are laid in the space between these
two, and they are distant from one another three feet. Into the ends of
the transverse beams which face the second long wall, are mortised the
ends of the same number of rafters erected toward the upright posts
which are placed upon the second long wall, and in this manner is made
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the second inclined side wall of the hood. Into the ends of the transverse
beams facing the third long wall, are mortised the ends of the same
number of rafters rising toward the rafters of the first inclined side of
the second hood, and in this manner is made the other inclined side of
the second hood. But to prevent this from falling in upon the opposite
inclined side of the hood, and that again upon the opposite vertical one,
there are many iron rods reaching from some of the rafters to those
opposite them; and this is also prevented in part by means of a few tie−beams,
extending from the back of the rafters to the back of those which are behind
them. These tie−beams are two palms thick and wide, and have holes made
through them at each end; each of the rafters is bound round with iron
bands three digits wide and half a digit thick, which hold together the ends
of the tie−beams of which I have spoken; and so that the joints may be firm,
an iron nail, passing through the plate on both sides, is driven through the
holes in the ends of the beams. Since one weight counter−balances another, the
rafters on the opposite hoods cannot fall. The tie−beams and middle posts
which have to support the gutters and the roof, are made in every particular
as I stated above, except only that the second set of middle rafters are not
longer than the first set of middle rafters, and that the little beams which
reach from the back of each rafter of the second set of middle rafters nearly
to the gutter are not longer than the little beams which reach from the back
of each rafter of the first set of middle rafters almost to the gutter. In this
part of the building, against the second long wall, are the furnaces in which
copper is alloyed with lead, and in which "slags" are re−smelted. Against
the third long wall are the furnaces in which silver and lead are liquated from
copper. The interior is also occupied by two cranes, of which one deposits
on the ground the cakes of copper lifted out of the moulding pans; the other
lifts them from the ground into the second furnace.
On the third and the fourth long walls are set twenty−one beams eighteen
feet and three palms long. In mortises in them, two feet behind the third long
wall, are set the ends of the same number of rafters erected opposite to the
rafters of the other inclined wall of the second furnace hood, and in this
manner is made the third inclined wall, exactly similar to the others. The
ends of as many rafters are mortised into these beams where they are fixed in
the fourth long wall; these rafters are erected obliquely, and rest against the
backs of the preceding ones and support the roof, which consists entirely of
burnt tiles and has the usual substructures. In this part of the building
there are two rooms, in the first of which the cakes of copper, and in the other
the cakes of lead, are stored.
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In the space enclosed between the ninth and tenth transverse walls and
the second and fifth long walls, a post twelve feet high and two feet wide and
thick is erected on a rock foundation; it is distant thirteen feet from the
second long wall, and six from the fifth long wall. Upon this post and upon
the ninth transverse wall is laid a beam thirty−three feet and three palms
long, and two palms wide and thick. Another beam, also of the same length,
width and thickness, is laid upon the same post and upon the tenth transverse
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wall, and the ends of these two beams where they meet are joined by means
of iron staples. On these beams and on the fifth long wall are placed ten
cross−beams, eight feet and three palms long, the first of which is placed on
the ninth transverse wall, the last on the tenth, the remainder in the space
between them; they are distant from one another three feet. Into the
ends of the cross−beams facing the second long wall, are mortised the ends of
the same number of rafters inclined toward the posts which stand vertically
upon the second long wall. This, again, is the manner in which the inclined
side of the furnace hood is made, just as with the others; at the top
where the fumes are emitted it is two feet distant from the vertical side.
The ends of the same number of rafters are mortised into the cross−beams,
where they are set in the fifth long wall; each of them is set up obliquely and
rests against the back of one of the preceding set; they support the roof,
made of burnt tiles. In this part of the building, against the second long
wall, are four furnaces in which lead is separated from silver, together with
the cranes by means of which the domes are lifted from the crucibles.
In that part of the building which lies between the first long wall and
the break in the second long wall, is the stamp with which the copper cakes
are crushed, and the four stamps with which the accretions that are chipped
off the walls of the furnace are broken up and crushed to powder, and likewise
the bricks on which the exhausted liquation cakes of copper are stood to
be "dried." This room has the usual roof, as also has the space between
the seventh transverse wall and the twelfth and thirteenth transverse walls.
At the sides of these rooms are the fifth, the sixth, and the third long
walls. This part of the building is divided into two parts, in the first of
which stand the little furnaces in which the artificer assays metals; and the
bone ash, together with the other powders, are kept here. In the other room
is prepared the powder from which the hearths and the crucibles of the fur−
naces are made. Outside the building, at the back of the fourth long wall,
near the door to the left as you enter, is a hearth in which smaller
masses of lead are melted from large ones, that they may be the more easily
weighed; because the masses of lead, just as much as the cakes of copper,
ought to be first prepared so that they can be weighed, and a definite weight
can be melted and alloyed in the furnaces. To begin with, the hearth in
which the masses of lead are liquefied is six feet long and five wide; it is
protected on both sides by rocks partly sunk into the earth, but a palm higher
than the hearth, and it is lined in the inside with lute. It slopes toward the
middle and toward the front, in order that the molten lead may run down
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and flow out into the dipping−pot. There is a wall at the back of the hearth
which protects the fourth long wall from damage by the heat; this wall,
which is made of bricks and lute, is four feet high, three palms thick, and five
feet long at the bottom, and at the top three feet and two palms long; there−
fore it narrows gradually, and in the upper part are laid seven bricks, the
middle ones of which are set upright, and the end ones inclined; they are all
thickly coated with lute. In front of the hearth is a dipping−pot, whose pit is
a foot deep, and a foot and three palms wide at the top, and gradually narrows.
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AHEARTH. BROCKS SUNK INTO THE GROUND. CWALLS WHICH PROTECT THE
FOURTH LONG WALL FROM DAMAGE BY FIRE. DDIPPING−POT. EMASSES OF LEAD.
FTROLLEY. GITS WHEELS. HCRANE. ITONGS. KWOOD. LMOULDS.
MLADLE. NPICK. OCAKES.
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When the masses of lead are to be melted, the workman first places the wood
in the hearth so that one end of each billet faces the wall, and the other end
the dipping−pot. Then, assisted by other workmen, he pushes the mass
of lead forward with crowbars on to a low trolley, and draws it to the
crane. The trolley consists of planks fastened together, is two and one−half
feet wide and five feet long, and has two small iron axles, around which at
each end revolve small iron wheels, two palms in diameter and as many digits
wide. The trolley has a tongue, and attached to this is a rope, by which it is
drawn to the crane. The crane is exactly similar to those in the second part
of the works, except that the crane−arm is not so long. The tongs in whose
jaws 6 the masses of lead are seized, are two feet a palm and two digits long;
both of the jaws, when struck with a hammer, impinge upon the mass and are
driven into it. The upper part of both handles of the tongs are curved back,
the one to the right, the other to the left, and each handle is engaged in one
of the lowest links of two short chains, which are three links long. The upper
links are engaged in a large round ring, in which is fixed the hook of a chain
let down from the pulley of the crane−arm. When the crank of the crane
is turned, the mass is lifted and is carried by the crane−arm to the hearth and
placed on the wood. The workmen wheel up one mass after another and
place them in a similar manner on the wood of the hearth; masses which
weigh a total of about a hundred and sixty centumpondía 7 are usually placed
upon the wood and melted at one time. Then a workman throws charcoal
on the masses, and all are made ready in the evening. If he fears that it may
rain, he covers it up with a cover, which may be moved here and there; at the
back this cover has two legs, so that the rain which it collects may flow down
the slope on to the open ground. Early in the morning of the following day,
he throws live coals on the charcoal with a shovel, and by this method the
masses of lead melt, and from time to time charcoal is added. The lead, as
soon as it begins to run into the dipping−pot, is ladled out with an iron ladle
into copper moulds such as the refiners generally use. If it does not cool
immediately he pours water over it, and then sticks the pointed pick into
it and pulls it out. The pointed end of the pick is three palms long and
the round end is two digits long. It is necessary to smear the moulds with a
wash of lute, in order that, when they have been turned upside down and
struck with the broad round end of the pick, the cakes of lead may fall out
easily. If the moulds are not washed over with the lute, there is a risk that
they may be melted by the lead and let it through. Others take hold of a
billet of wood with their left hand, and with the heavy lower end of it they
pound the mould, and with the right hand they stick the point of the pick
into the cake of lead, and thus pull it out. Then immediately the workman
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pours other lead into the empty moulds, and this he does until the work of
melting the lead is finished. When the lead is melted, something similar to
litharge is produced; but it is no wonder that it should be possible to make
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it in this case, when it used formerly to be produced at Puteoli from lead
alone when melted by a fierce fire in the cupellation furnace. 8 Afterward
these cakes of lead are carried into the lead store−room.
The cakes of copper, put into wheelbarrows, are carried into the third
part of the building, where each is laid upon a saddle, and is broken up by
the impact of successive blows from the iron−shod stamp. This machine
is made by placing upon the ground a block of oak, five feet long and three feet
ABLOCK OF WOOD. BUPRIGHT POSTS. CTRANSVERSE BEAMS. DHEAD OF THE
STAMP. EITS TOOTH. FTHE HOLE IN THE STAMP−STEM. GIRON BAR. HMASSES
OF LEAD. ITHE BRONZE SADDLE. KAXLE. LITS ARMS. MLITTLE IRON AXLE.
NBRONZE PIPE.
wide and thick; it is cut out in the middle for a length of two feet and two
palms, a width of two feet, and a depth of three palms and two digits, and is
open in front; the higher part of it is at the back, and the wide part lies flat
in the block. In the middle of it is placed a bronze saddle. Its base
is a palm and two digits wide, and is planted between two masses of
lead, and extends under them to a depth of a palm on both sides.
The whole saddle is three palms and two digits wide, a foot long, and
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two palms thick. Upon each end of the block stands a post, a cubit wide
and thick, the upper end of which is somewhat cut away and is mortised into
the beams of the building. At a height of four feet and two digits above the
block there are joined to the posts two transverse beams, each of which is
three palms wide and thick; their ends are mortised into the upright posts,
and holes are bored through them; in the holes are driven iron claves,
horned in front and so driven into the post that one of the horns of each
points upward and the other downward; the other end of each clavis is
perforated, and a wide iron wedge is inserted and driven into the holes, and
thus holds the transverse beams in place. These transverse beams have in the
middle a square opening three palms and half a digit wide in each
direction, through which the iron−shod stamp passes. At a height of three
feet and two palms above these transverse beams there are again two beams
of the same kind, having also a square opening and holding the same stamp.
This stamp is square, eleven feet long, three palms wide and thick; its iron
shoe is a foot and a palm long; its head is two palms long and wide, a palm
two digits thick at the top, and at the bottom the same number of digits, for
it gradually narrows. But the tail is three palms long; where the head
begins is two palms wide and thick, and the further it departs from the same
the narrower it becomes. The upper part is enclosed in the stamp−stem, and
it is perforated so that an iron bolt may be driven into it; it is bound by three
rectangular iron bands, the lowest of which, a palm wide, is between the iron
shoe and the head of the stamp; the middle band, three digits wide, follows
next and binds round the head of the stamp, and two digits above is the
upper one, which is the same number of digits wide. At a distance of two
feet and as many digits above the lowest part of the iron shoe, is a rectangular
tooth, projecting from the stamp for a distance of a foot and a palm; it is
two palms thick, and when it has extended to a distance of six digits from the
stamp it is made two digits narrower. At a height of three palms upward
from the tooth there is a round hole in the middle of the stamp−stem, into
which can be thrust a round iron bar two feet long and a digit and a half in
diameter; in its hollow end is fixed a wooden handle two palms and the same
number of digits long. The bar rests on the lower transverse beam, and holds
up the stamp when it is not in use. The axle which raises the stamp
has on each side two arms, which are two palms and three digits distant
from each other, and which project from the axle a foot, a palm and two
digits; penetrating through them are bolts, driven in firmly; the arms are
each a palm and two digits wide and thick, and their round heads, for a foot
downward on either side, are covered with iron plates of the same width as
the arms and fastened by iron nails. The head of each arm has a round
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hole, into which is inserted an iron pin, passing through a bronze pipe; this
little axle has at the one end a wide head, and at the other end a perforation
through which is driven an iron nail, lest this little axle should fall out of the
arms. The bronze pipe is two palms long and one in diameter; the little
iron axle penetrates through its round interior, which is two digits in diameter.
The bronze pipe not only revolves round the little iron axle, but it also
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rotates with it; therefore, when the axle revolves, the little axle and
the bronze tube in their turn raise the tooth and the stamp. When the
little iron axle and the bronze pipe have been taken out of the arms, the tooth
of the stamps is not raised, and other stamps may be raised without this one.
Further on, a drum with spindles fixed around the axle of a water−wheel
moves the axle of a toothed drum, which depresses the sweeps of the bellows
in the adjacent fourth part of the building; but it turns in the contrary
direction; for the axis of the drum which raises the stamps turns toward
the north, while that one which depresses the sweeps of the bellows turns
toward the south.
Those cakes which are too thick to be rapidly broken by blows from
the iron−shod stamp, such as are generally those which have settled in the
bottom of the crucible, 9 are carried into the first part of the building. They
are there heated in a furnace, which is twenty−eight feet distant from the
second long wall and twelve feet from the second transverse wall. The three
sides of this furnace are built of rectangular rocks, upon which bricks are laid;
the back furnace wall is three feet and a palm high, and the rear of the side
walls is the same; the side walls are sloping, and where the furnace is open in
front they are only two feet and three palms high; all the walls are a foot and
a palm thick. Upon these walls stand upright posts not less thick, in order
that they may bear the heavy weight placed upon them, and they are covered
with lute; these posts support the sloping chimney and penetrate through
the roof. Moreover, not only the ribs of the chimney, but also the rafters,
are covered thickly with lute. The hearth of the furnace is six feet
long on each side, is sloping, and is paved with bricks. The cakes of copper
are placed in the furnace and heated in the following way. They are first of
all placed in the furnace in rows, with as many small stones the size of an egg
between, so that the heat of the fire can penetrate through the spaces between
them; indeed, those cakes which are placed at the bottom of the crucible are
each raised upon half a brick for the same reason. But lest the last row,
which lies against the mouth of the furnace, should fall out, against the mouth
are placed iron plates, or the copper cakes which are the first taken from the
crucible when copper is made, and against them are laid exhausted liquation
cakes or rocks. Then charcoal is thrown on the cakes, and then live coals;
at first the cakes are heated by a gentle fire, and afterward more charcoal is
added to them until it is at times three−quarters of a foot deep. A fiercer fire
is certainly required to heat the hard cakes of copper than the fragile ones.
When the cakes have been sufficiently heated, which usually occurs within
the space of about two hours, the exhausted liquation cakes or the rocks
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and the iron plate are removed from the mouth of the furnace. Then the
hot cakes are taken out row after row with a two−pronged rabble, such as the
one which is used by those who "dry" the exhausted liquation cakes.
Then the first cake is laid upon the exhausted liquation cakes, and beaten by
two workmen with hammers until it breaks; the hotter the cakes are, the
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sooner they are broken up; the less hot, the longer it takes, for now and
then they bend into the shape of copper basins. When the first cake has
been broken, the second is put on to the other fragments and beaten until it
breaks into pieces, and the rest of the cakes are broken up in the same manner
in due order. The head of the hammer is three palms long and one wide,
and sharpened at both ends, and its handle is of wood three feet long.
When they have been broken by the stamp, if cold, or with hammers if hot,
the fragments of copper or the cakes are carried into the store−room for
copper.
ABACK WALL. BWALLS AT THE SIDES. CUPRIGHT POSTS. DCHIMNEY.
ETHE CAKES ARRANGED. FIRON PLATES. GROCKS. HRABBLE WITH TWO
PRONGS. IHAMMERS.
The foreman of the works, according to the different proportions of
silver in each centumpondíum of copper, alloys it with lead, without which
he could not separate the silver from the copper. 10 If there be a moderate
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amount of silver in the copper, he alloys it fourfold; for instance, if in three−
quarters of a centumpondium of copper there is less than the following pro−
portions, í.e.: half a libra of silver, or half a líbra and a sícílícus, or half a líbra
and a semí−uncía, or half a libra and semí−uncía and a sícílícus, then rich
leadthat is, that from which the silver has not yet been separatedis
added, to the amount of half a centumpondíum or a whole centumpondíum, or
a whole and a half, in such a way that there may be in the copper−lead alloy
some one of the proportions of silver which I have just mentioned, which is
the first alloy. To this "first" alloy is added such a weight of de−silverized
lead or litharge as is required to make out of all of these a single liquation cake
that will contain approximately two centumpondía of lead; but as usually
from one hundred and thirty líbrae of litharge only one hundred líbrae of lead
are made, a greater proportion of litharge than of de−silverized lead is added
as a supplement. Since four cakes of this kind are placed at the same time
into the furnace in which the silver and lead is liquated from copper, there
will be in all the cakes three centumpondía of copper and eight centumpondía
of lead. When the lead has been liquated from the copper, it weighs six
centumpondía, in each centumpondíum of which there is a quarter of a líbra
and almost a sícílícus of silver. Only seven uncíae of the silver remain in the
exhausted liquation cakes and in that copper−lead alloy which we call
"liquation thorns"; they are not called by this name so much because they
have sharp points as because they are base. If in three−quarters of a centum−
pondíum of copper there are less than seven uncía and a semí−uncía or a bes
of silver, then so much rich lead must be added as to make in the copper and
lead alloy one of the proportions of silver which I have already mentioned.
This is the "second" alloy. To this is again to be added as great a weight
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of de−silverized lead, or of litharge, as will make it possible to obtain from that
alloy a liquation cake containing two and a quarter centumpondía of lead,
in which manner in four of these cakes there will be three centumpondía of
copper and nine centumpondía of lead. The lead which liquates from these
cakes weighs seven centumpondia, in each centumpondíum of which there is
a quarter of a líbra of silver and a little more than a sícílícus. About seven
uncíae of silver remain in the exhausted liquation cakes and in the liquation
thorns, if we may be allowed to make common the old name ( spínae =thorns)
and bestow it upon a new substance. If in three−quarters of a centumpondíum
of copper there is less than three−quarters of a líbra of silver, or three−quarters
and a semí−uncía, then as much rich lead must be added as will produce one
of the proportions of silver in the copper−lead alloy above mentioned; this
is the "third" alloy. To this is added such an amount of de−silverized lead
or of litharge, that a liquation cake made from it contains in all two and
three−quarters centumpondía of lead. In this manner four such cakes will
contain three centumpondía of copper and eleven centumpondía of lead.
The lead which these cakes liquate, when they are melted in the furnace,
weighs about nine centumpondía, in each centumpondíum of which there is
a quarter of a líbra and more than a sícílícus of silver; and seven uncíae of
silver remain in the exhausted liquation cakes and in the liquation thorns.
If, however, in three−quarters of a centumpondíum of copper there is less than
ten−twelfths of a líbra or ten−twelfths of a libra and a semí−uncía of silver,
then such a proportion of rich lead is added as will produce in the copper−lead
alloy one of the proportions of silver which I mentioned above; this is the
"fourth" alloy. To this is added such a weight of de−silverized lead or of
litharge, that a liquation cake made from it contains three centumpondía of
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lead, and in four cakes of this kind there are three centumpondía of copper and
twelve centumpondía of lead. The lead which is liquated therefrom weighs
about ten centumpondía, in each centumpondíum of which there is a quarter
of a libra and more than a semí−uncía of silver, or seven uncíae; a bes, or
seven uncíae and a semí−uncía, of silver remain in the exhausted liquation
cakes and in the liquation thorns.
Against the second long wall in the second part of the building, whose
area is eighty feet long by thirty−nine feet wide, are four furnaces in which
the copper is alloyed with lead, and six furnaces in which "slags" are re−
smelted. The interior of the first kind of furnace is a foot and three palms wide,
two feet three digits long; and of the second is a foot and a palm wide and a foot
three palms and a digit long. The side walls of these furnaces are the same
height as the furnaces in which gold or silver ores are smelted. As the whole
room is divided into two parts by upright posts, the front part must have,
first, two furnaces in which "slags" are re−melted; second, two furnaces in
which copper is alloyed with lead; and third, one furnace in which "slags" are
re−melted. The back part of the room has first, one furnace in which "slags"
are re−melted; next, two furnaces in which copper is alloyed with lead; and
third, two furnaces in which "slags" are re−melted. Each of these is six feet
distant from the next; on the right side of the first is a space of three feet
and two palms, and on the left side of the last one of seven feet. Each pair of
furnaces has a common door, six feet high and a cubit wide, but the first and
the tenth furnace each has one of its own. Each of the furnaces is set in an arch
of its own in the back wall, and in front has a forehearth pit; this is filled with
a powder compound rammed down and compressed in order to make a crucible.
Under each furnace is a hidden receptacle for the moisture, 11 from which a
vent is made through the back wall toward the right, which allows the
vapour to escape. Finally, to the right, in front, is the copper mould into
which the copper−lead alloy is poured from the forehearth, in order that
liquation cakes of equal weight may be made. This copper mould is a digit
thick, its interior is two feet in diameter and six digits deep. Behind the
second long wall are ten pairs of bellows, two machines for compressing them,
and twenty instruments for inflating them. The way in which these should
be made may be understood from Book IX.
The smelter, when he alloys copper with lead, with his hand throws into
the heated furnace, first the large fragments of copper, then a basketful of
charcoal, then the smaller fragments of copper. When the copper is melted
and begins to run out of the tap−hole into the forehearth, he throws litharge
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into the furnace, and, lest part of it should fly away, he first throws
charcoal over it, and lastly lead. As soon as he has thrown into the furnace
the copper and the lead, from which alloy the first liquation cake is made, he
again throws in a basket of charcoal, and then fragments of copper are thrown
over them, from which the second cake may be made. Afterward with a
rabble he skims the "slag" from the copper and lead as they flow into the
forehearth. Such a rabble is a board into which an iron bar is fixed; the
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board is made of elder−wood or willow, and is ten digits long, six wide, and one
and a half digits thick; the iron bar is three feet long, and the wooden
handle inserted into it is two and a half feet long. While he purges the
alloy and pours it out with a ladle into the copper mould, the fragments of
copper from which he is to make the second cake are melting. As soon as
this begins to run down he again throws in litharge, and when he has put on
more charcoal he adds the lead. This operation he repeats until thirty
liquation cakes have been made, on which work he expends nine hours, or at
most ten; if more than thirty cakes must be made, then he is paid for
another shift when he has made an extra thirty.
At the same time that he pours the copper−lead alloy into the copper
mould, he also pours water slowly into the top of the mould. Then, with a
cleft stick, he takes a hook and puts its straight stem into the molten cake.
The hook itself is a digit and a half thick; its straight stem is two palms
long and two digits wide and thick. Afterward he pours more water over the
cakes. When they are cold he places an iron ring in the hook of the chain
AFURNACE IN WHICH "SLAGS" ARE RE−SMELTED. BFURNACE IN WHICH COPPER IS
ALLOYED WITH LEAD. CDOOR. DFORE−HEARTHS ON THE GROUND. ECOPPER
MOULDS. FRABBLE. GHOOK. HCLEFT STICK. IARM OF THE CRANE.
KTHE HOOK OF ITS CHAIN.
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700
let down from the pulley of the crane arm; the inside diameter of this ring
is six digits, and it is about a digit and a half thick; the ring is then engaged
in the hook whose straight stem is in the cake, and thus the cake is raised from
the mould and put into its place.
The copper and lead, when thus melted, yield a small amount of "slag" 12
and much litharge. The litharge does not cohere, but falls to pieces like the
residues from malt from which beer is made. Pompholyx adheres to the walls
in white ashes, and to the sides of the furnace adheres spodos.
In this practical manner lead is alloyed with copper in which there is but
a moderate portion of silver. If, however, there is much silver in it, as, for
instance, two líbrae, or two líbrae and a bes, to the centumpondium, which
weighs one hundred and thirty−three and a third líbrae, or one hundred and
forty−six librae and a bes, 13 then the foreman of the works adds to a centum−
pondíum of such copper three centumpondía of lead, in each centumpondium
of which there is a third of a líbra of silver, or a third of a libra and a semí−
uncía. In this manner three liquation cakes are made, which contain
altogether three centumpondía of copper and nine centumpondía of lead. 14 The
lead, when it has been liquated from the copper, weighs seven centumpondia;
and in each centumpondíum if the centumpondium of copper contain two
líbrae of silver, and the lead contain a third of a líbra there will be a líbra
and a sixth and more than a semí−uncía of silver; while in the exhausted
liquation cakes, and in the liquation thorns, there remains a third of a líbra.
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If a centumpondíum of copper contains two líbrae and a bes of silver, and
the lead a third of a libra and a semí−uncía, there will be in each liquation
cake one and a half líbrae and a semí−uncia, and a little more than a sicilicus
of silver. In the exhausted liquation cakes there remain a third of a libra
and a semi−uncia of silver.
If there be in the copper only a minute proportion of silver, it cannot be
separated easily until it has been re−melted in other furnaces, so that in
the "bottoms" there remains more silver and in the "tops" less. 15 This
AFURNACE. BFOREHEARTH. CDIPPING−POT. DCAKES.
furnace, vaulted with unbaked bricks, is similar to an oven, and also to the
cupellation furnace, in which the lead is separated from silver, which I described
in the last book. The crucible is made of ashes, in the same manner as
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in the latter, and in the front of the furnace, three feet above the floor of
the building, is the mouth out of which the re−melted copper flows into a
forehearth and a dipping−pot. On the left side of the mouth is an aperture,
through which beech−wood may be put into the furnace to feed the fire. If
in a centumpondíum of copper there were a sixth of a líbra and a semí−uncía of
silver, or a quarter of a libra, or a quarter of a líbra and a semi−uncia there is
re−melted at the same time thirty−eight centumpondía of it in this furnace, until
there remain in each centumpondíum of the copper "bottoms" a third of a
líbra and a semí−uncía of silver. For example, if in each centumpondium of
copper not yet re−melted, there is a quarter of a libra and a semi−uncia of silver,
then the thirty−eight centumpondia that are smelted together must contain a
total of eleven líbrae and an uncía of silver. Since from fifteen centumpondía
of re−melted copper there was a total of four and a third líbrae and a semi−uncia
of silver, there remain only two and a third librae. Thus there is left in the
"bottoms," weighing twenty−three centumpondía, a total of eight and three−
quarter líbrae of silver. Therefore, each centumpondíum of this contains a
third of a libra and a semí−uncía, a drachma, and the twenty−third part of a
drachma of silver; from such copper it is profitable to separate the silver.
In order that the master may be more certain of the number of centumpondía
of copper in the "bottoms," he weighs the "tops" that have been drawn
off from it; the "tops" were first drawn off into the dipping−pot, and cakes
were made from them. Fourteen hours are expended on the work of thus
dividing the copper. The "bottoms," when a certain weight of lead has
been added to them, of which alloy I shall soon speak, are melted in
the blast furnace; liquation cakes are then made, and the silver is afterward
separated from the copper. The "tops" are subsequently melted
in the blast furnace, and re−melted in the refining furnace, in order that
red copper shall be made 16 ; and the "tops" from this are again smelted in
the blast furnace, and then again in the refining furnace, that therefrom
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shall be made caldaríum copper. But when the copper, yellow or red or caldar−
íum is re−smelted in the refining furnace, forty centumpondía are placed in
it, and from it they make at least twenty, and at most thirty−five, centum−
pondía. About twenty−two centumpondía of exhausted liquation cakes and
ten of yellow copper and eight of red, are simultaneously placed in this latter
furnace and smelted, in order that they may be made into refined copper.
The copper "bottoms" are alloyed in three different ways with lead. 17
First, five−eights of a centumpondíum of copper and two and three−
quarters centumpondia of lead are taken; and since one liquation cake is made
from this, therefore two and a half centumpondía of copper and eleven cen−
tumpondía of lead make four liquation cakes. Inasmuch as in each centumpon−
dium of copper there is a third of a líbra of silver, there would be in the whole
of the copper ten−twelfths of a líbra of silver; to these are added four centum−
pondía of lead re−melted from "slags," each centumpondíum of which contains
a sícilícus and a drachma of silver, which weights make up a total of an uncía
and a half of silver. There is also added seven centumpondía of de−silverized
lead, in each centumpondíum of which there is a drachma of silver; therefore
in the four cakes of copper−lead alloy there is a total of a líbra, a sicílícus and
a drachma of silver. In each single centumpondíum of lead, after it has been
liquated from the copper, there is an uncía and a drachma of silver, which alloy
we call "poor" argentiferous lead, because it contains but little silver. But
as five cakes of that kind are placed together in the furnace, they liquate
from them usually as much as nine and three−quarters centumpondía of poor
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argentiferous lead, in each centumpondíum of which there is an uncía and a
drachma of silver, or a total of ten uncíae less four drachmae. Of the liquation
thorns there remain three centumpondía, in each centumpondíum of which
there are three sícilící of silver; and there remain four centumpondía of
exhausted liquation cakes, each centumpondíum of which contains a semí−
uncía or four and a half drachmae. Inasmuch as in a centumpondíum of copper
"bottoms" there is a third of a líbra and a semí−uncía of silver, in five of those
cakes there must be more than one and a half uncíae and half a drachma of
silver.
Then, again, from another two and a half centumpondía of copper
"bottoms," together with eleven centumpondía of lead, four liquation cakes
are made. If in each centumpondium of copper there was a third of a líbra of
silver, there would be in the whole of the centumpondía of base metal five−
sixths of a líbra of the precious metal. To this copper is added eight centum−
pondía of poor argentiferous lead, each centumpondíum of which contains an
uncía and a drachma of silver, or a total of three−quarters of a líbra of silver.
There is also added three centumpondía of de−silverized lead, in each centum−
pondíum of which there is a drachma of silver. Therefore, four liquation
cakes contain a total of a líbra, seven uncíae, a sícílícus and a drachma of silver;
thus each centumpondíum of lead, when it has been liquated from the copper,
contains an uncía and a half and a sícílícus of silver, which alloy we call
"medium" silver−lead.
Then, again, from another two and a half centumpondía of copper
"bottoms," together with eleven centumpondía of lead, they make four
liquation cakes. If in each centumpondium of copper there were likewise a
third of a líbra of silver, there will be in all the weight of the base metal five−
sixths of a libra of the precious metal. To this is added nine centumpondía
of medium silver−lead, each centumpondíum of which contains an uncía and
a half and a sícílícus of silver; or a total of a libra and a quarter and a semí−
uncía and a sícílícus of silver. And likewise they add two centumpondía of
poor silver−lead, in each of which there is an uncía and a drachma of silver.
Therefore the four liquation cakes contain two and a third líbrae of silver.
Each centumpondíum of lead, when it has been liquated from the copper,
contains a sixth of a líbra and a semí−uncía and a drachma of silver. This
alloy we call "rich" silver−lead; it is carried to the cupellation furnace,
in which lead is separated from silver. I have now mentioned in how many
ways copper containing various proportions of silver is alloyed with lead,
and how they are melted together in the furnace and run into the casting pan.
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705
Now I will speak of the method by which lead is liquated from copper
simultaneously with the silver. The liquation cakes are raised from the
ground with the crane, and placed on the copper plates of the furnaces. The
hook of the chain let down from the arm of the crane, is inserted in a
ring of the tongs, one jaw of which has a tooth; a ring is engaged in each
of the handles of the tongs, and these two rings are engaged in a third, in
which the hook of the chain is inserted. The tooth on the one jaw of the
tongs is struck by a hammer, and driven into the hole in the cake, at the point
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706
where the straight end of the hook was driven into it when it was lifted out
of the copper mould; the other jaw of the tongs, which has no tooth,
squeezes the cake, lest the tooth should fall out of it; the tongs are one and
a half feet long, each ring is a digit and a half thick, and the inside is a palm
and two digits in diameter. Those cranes by which the cakes are lifted out
of the copper pans and placed on the ground, and lifted up again from there
and placed in the furnaces, are two in numberone in the middle space
between the third transverse wall and the two upright posts, and the other in
ACRANE. BDRUM CONSISTING OF RUNDLES. CTOOTHED DRUM. DTROLLEY
AND ITS WHEELS. ETRIANGULAR BOARD. FCAKES. GCHAIN OF THE CRANE.
HITS HOOK. IRING. KTHE TONGS.
the middle space between the same posts and the seventh transverse wall.
The rectangular crane−post of both of these is two feet wide and thick, and
is eighteen feet from the third long wall, and nineteen from the second long
wall. There are two drums in the framework of eachone drum consisting
of rundles, the other being toothed. The crane−arm of each extends seventeen
feet, three palms and as many digits from the post. The trolley of each
crane is two feet and as many palms long, a foot and two digits wide, and a
palm and two digits thick; but where it runs between the beams of the
crane−arm it is three digits wide and a palm thick; it has five notches, in
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707
which turn five brass wheels, four of which are small, and the fifth much
larger than the rest. The notches in which the small wheels turn are two
palms long and as much as a palm wide; those wheels are a palm wide and
a palm and two digits in diameter; four of the notches are near the four
corners of the trolley; the fifth notch is between the two front ones, and
it is two palms back from the front. Its pulley is larger than the rest, and
turns in its own notch; it is three palms in diameter and one palm wide,
and grooved on the circumference, so that the iron chain may run in the
groove. The trolley has two small axles, to the one in front are fastened
three, and to the one at the back, the two wheels; two wheels run on the
one beam of the crane−arm, and two on the other; the fifth wheel, which is
larger than the others, runs between those two beams. Those people who
have no cranes place the cakes on a triangular board, to which iron cleats
are affixed, so that it will last longer; the board has three iron chains,
which are fixed in an iron ring at the top; two workmen pass a pole through
the ring and carry it on their shoulders, and thus take the cake to the furnace
in which silver is separated from copper.
From the vicinity of the furnaces in which copper is mixed with lead and
the "slags" are re−melted, to the third long wall, are likewise ten furnaces,
in which silver mixed with lead is separated from copper. If this space is
eighty feet and two palms long, and the third long wall has in the centre a
door three feet and two palms wide, then the spaces remaining at either side
of the door will be thirty−eight feet and two palms; and if each of the furnaces
occupies four feet and a palm, then the interval between each furnace and
the next one must be a foot and three palms; thus the width of the five
furnaces and four interspaces will be twenty−eight feet and a palm. There−
fore, there remain ten feet and a palm, which measurement is so divided
that there are five feet and two digits between the first furnace and
the transverse wall, and as many feet and digits between the fifth furnace
and the door; similarly in the other part of the space from the door to the
sixth furnace, there must be five feet and two digits, and from the tenth
furnace to the seventh transverse wall, likewise, five feet and two digits.
The door is six feet and two palms high; through it the foreman of the officína
and the workmen enter the store−room in which the silver−lead alloy is kept.
Each furnace has a bed, a hearth, a rear wall, two sides and a front,
and a receiving−pit. The bed consists of two sole−stones, four rectangular
stones, and two copper plates; the sole−stones are five feet and a palm
long, a cubit wide, a foot and a palm thick, and they are sunk into the ground,
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708
so that they emerge a palm and two digits; they are distant from each other
about three palms, yet the distance is narrower at the back than the front.
Each of the rectangular stones is two feet and as many palms long, a cubit
wide, and a cubit thick at the outer edge, and a foot and a palm thick on the
inner edge which faces the hearth, thus they form an incline, so that there is a
slope to the copper plates which are laid upon them. Two of these rectang−
ular stones are placed on one sole−stone; a hole is cut in the upper edge of
each, and into the holes are placed iron clamps, and lead is poured in; they
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are so placed on the sole−stones that they project a palm at the sides, and at the
front the sole−stones project to the same extent; if rectangular stones are
not available, bricks are laid in their place. The copper plates are four feet
two palms and as many digits long, a cubit wide, and a palm thick; each
edge has a protuberance, one at the front end, the other at the back; these
are a palm and three digits long, and a palm wide and thick. The plates are
so laid upon the rectangular stones that their rear ends are three digits from
the third long wall; the stones project beyond the plate the same number
of digits in front, and a palm and three digits at the sides. When the plates
have been joined, the groove which is between the protuberances is a palm
and three digits wide, and four feet long, and through it flows the silver−lead
which liquates from the cakes. When the plates are corroded either by the
fire or by the silver−lead, which often adheres to them in the form of stalac−
tites, and is chipped off, they are exchanged, the right one being placed to the
left, and the left one, on the contrary, to the right; but the left side of the
plates, which, when the fusion of the copper took place, came into contact
with the copper, must lie flat; so that when the exchange of the plates has
been carried out, the protuberances, which are thus on the underside, raise
the plate from the stones, and they have to be partially chipped off, lest they
should prove an impediment to the work; and in each of their places is
laid a piece of iron, three palms long, a digit thick at both ends, and a palm
thick in the centre for the length of a palm and three digits.
The passage under the plates between the rectangular stones is a foot
wide at the back, and a foot and a palm wide at the front, for it gradually
widens out. The hearth, which is between the sole−stones, is covered with a
bed of hearth−lead, taken from the crucible in which lead is separated from
silver. The rear end is the highest, and should be so high that it reaches to
within six digits of the plates, from which point it slopes down evenly to the
front end, so that the argentiferous lead alloy which liquates from the cakes
can flow into the receiving−pit. The wall built against the third long wall
in order to protect it from injury by fire, is constructed of bricks joined
together with lute, and stands on the copper plates; this wall is two feet, a
palm and two digits high, two palms thick, and three feet, a palm and three
digits wide at the bottom, for it reaches across both of them; at the top it is
three feet wide, for it rises up obliquely on each side. At each side of this wall,
at a height of a palm and two digits above the top of it, there is inserted in a
hole in the third long wall a hooked iron rod, fastened in with molten lead;
the rod projects two palms from the wall, and is two digits wide and one
digit thick; it has two hooks, the one at the side, the other at the end.
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Both of these hooks open toward the wall, and both are a digit thick, and
both are inserted in the last, or the adjacent, links of a short iron chain. This
chain consists of four links, each of which is a palm and a digit long and half
a digit thick; the first link is engaged in the first hole in a long iron rod, and
one or other of the remaining three links engages the hook of the hooked rod.
The two long rods are three feet and as many palms and digits long, two
digits wide, and one digit thick; both ends of both of these rods have holes,
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711
ASOLE−STONES. BRECTANGULAR STONES. CCOPPER PLATES. DFRONT PANEL.
ESIDE PANELS. FBAR. GFRONT END OF THE LONG IRON RODS. HSHORT CHAIN.
IHOOKED ROD. KWALL WHICH PROTECTS THE THIRD LONG WALL FROM INJURY BY
FIRE. LTHIRD LONG WALL. MFEET OF THE PANELS. NIRON BLOCKS. OCAKES.
PHEARTH. QRECEIVING−PIT.
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712
the back one of which is round and a digit in diameter, and in this is engaged
the first link of the chain as I have stated; the hole at the front end is two
digits and a half long and a digit and a half wide. This end of each rod
is made three digits wide, while for the rest of its length it is only two digits,
and at the back it is two and a half digits. Into the front hole of each rod is
driven an iron bar, which is three feet and two palms long, two digits wide
and one thick; in the end of this bar are five small square holes, two−thirds
of a digit square; each hole is distant from the other half a digit, the first
being at a distance of about a digit from the end. Into one of these holes the
refiner drives an iron pin; if he should desire to make the furnace narrower,
then he drives it into the last hole; if he should desire to widen it, then into
the first hole; if he should desire to contract it moderately, then into one
of the middle holes. For the same reason, therefore, the hook is sometimes
inserted into the last link of the chain, and sometimes into the third or the
second. The furnace is widened when many cakes are put into it, and con−
tracted when there are but few, but to put in more than five is neither usual
nor possible; indeed, it is because of thin cakes that the walls are contracted.
The bar has a hump, which projects a digit on each side at the back, of the
same width and thickness as itself. These humps project, lest the bar should
slip through the hole of the right−hand rod, in which it remains fixed when
it, together with the rods, is not pressing upon the furnace walls.
There are three panels to the furnacetwo at the sides, one in front
and another at the back. Those which are at the sides are three feet
and as many palms and two digits long, and two feet high; the front one is
two feet and a palm and three digits long, and, like the side ones, two feet
high. Each consists of iron bars, of feet, and of iron plates. Those which are
at the side have seven bars, the lower and upper of which are of the same
length as the panels; the former holds up the upright bars; the latter is
placed upon them; the uprights are five in number, and have the same height
as the panels; the middle ones are inserted into holes in the upper and lower
bars; the outer ones are made of one and the same bar as the lower and
upper ones. They are two digits wide and one thick. The front panel has
five bars; the lower one holds similar uprights, but there are three of them
only; the upper bar is placed on them. Each of these panels has two feet
fixed at each end of the lower bar, and these are two palms long, one wide,
and a digit thick. The iron plates are fastened to the inner side of the bars
with iron wire, and they are covered with lute, so that they may last longer
and may be uninjured by the fire. There are, besides, iron blocks three palms
long, one wide, and a digit and a half thick; the upper surface of these is
1
713
somewhat hollowed out, so that the cakes may stand in them; these iron
blocks are dipped into a vessel in which there is clay mixed with water, and
they are used only for placing under the cakes of copper and lead alloy made
in the furnaces. There is more silver in these than in those which are
made of liquation thorns, or furnace accretions, or re−melted "slags." Two
iron blocks are placed under each cake, in order that, by raising it up, the fire
may bring more force to bear upon it; the one is put on the right bed−plate,
1
714
AFURNACE IN WHICH THE OPERATION OF LIQUATION IS BEING PERFORMED.
BFURNACE IN WHICH IT IS NOT BEING PERFORMED. CRECEIVING−PIT. DMOULDS.
ECAKES. FLIQUATION THORNS.
1
715
the other on the left. Finally, outside the hearth is the receiving−pit, which
is a foot wide and three palms deep; when this is worn away it is restored
with lute alone, which easily retains the lead alloy.
If four liquation cakes are placed on the plates of each furnace, then the
iron blocks are laid under them; but if the cakes are made from copper
"bottoms," or from liquation thorns, or from the accretions or "slags," of
which I have partly written above and will further describe a little later,
there are five of them, and because they are not so large and heavy, no blocks
are placed under them. Pieces of charcoal six digits long are laid between the
cakes, lest they should fall one against the other, or lest the last one should
fall against the wall which protects the third long wall from injury by fire. In
the middle empty spaces, long and large pieces of charcoal are likewise laid.
Then when the panels have been set up, and the bar has been closed, the
furnace is filled with small charcoal, and a wicker basket full of charcoal is
thrown into the receiving−pit, and over that are thrown live coals; soon
afterward the burning coal, lifted up in a shovel, is spread over all parts of
the furnace, so that the charcoal in it may be kindled; any charcoal which
remains in the receiving−pit is thrown into the passage, so that it may likewise
be heated. If this has not been done, the silver−lead alloy liquated from the
cakes is frozen by the coldness of the passage, and does not run down into the
receiving−pit.
After a quarter of an hour the cakes begin to drip silver−lead alloy, 18
which runs down through the openings between the copper plates into the
passage. When the long pieces of charcoal have burned up, if the cakes
lean toward the wall, they are placed upright again with a hooked bar, but
if they lean toward the front bar they are propped up by charcoal; more−
over, if some cakes shrink more than the rest, charcoal is added to the former
and not to the others. The silver drips together with the lead, for both melt
more rapidly than copper. The liquation thorns do not flow away, but remain
in the passage, and should be turned over frequently with a hooked bar, in
order that the silver−lead may liquate away from them and flow down into
the receiving pit; that which remains is again melted in the blast furnace,
while that which flows into the receiving pit is at once carried with the remain−
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716
ing products to the cupellation furnace, where the lead is separated from the
silver. The hooked bar has an iron handle two feet long, in which is set a
wooden one four feet long. The silver−lead which runs out into the receiving−
pit is poured out by the refiner with a bronze ladle into eight copper moulds,
which are two palms and three digits in diameter; these are first smeared
with a lute wash so that the cakes of silver−lead may more easily fall out
when they are turned over. If the supply of moulds fails because the silver−
lead flows down too rapidly into the receiving−pit, then water is poured on them,
in order that the cakes may cool and be taken out of them more rapidly;
thus the same moulds may be used again immediately; if no such necessity
urges the refiner, he washes over the empty moulds with a lute wash. The
ladle is exactly similar to that which is used in pouring out the metals that
are melted in the blast furnace. When all the silver−lead has run down from
the passage into the receiving−pit, and has been poured out into copper
moulds, the thorns are drawn out of the passage into the receiving−pit
with a rabble; afterward they are raked on to the ground from the receiving−
pit, thrown with a shovel into a wheelbarrow, and, having been conveyed
away to a heap, are melted once again. The blade of the rabble is two palms
and as many digits long, two palms and a digit wide, and joined to its
back is an iron handle three feet long; into the iron handle is inserted a
wooden one as many feet in length.
The residue cakes, after the silver−lead has been liquated from the
copper, are called "exhausted liquation cakes" ( fathíscentes ), because when
thus smelted they appear to be dried up. By placing a crowbar under the
cakes they are raised up, seized with tongs, and placed in the wheelbarrow;
they are then conveyed away to the furnace in which they are "dried."
The crowbar is somewhat similar to those generally used to chip off the
accretions that adhere to the walls of the blast furnace. The tongs are two
and a half feet long. With the same crowbar the stalactites are chipped off
from the copper plates from which they hang, and with the same instrument
the iron blocks are struck off the exhausted liquation cakes to which they
adhere. The refiner has performed his day' s task when he has liquated the
silver−lead from sixteen of the large cakes and twenty of the smaller ones;
if he liquates more than this, he is paid separately for it at the price for
extraordinary work.
Silver, or lead mixed with silver, which we call stannum, is separated by
the above method from copper. This silver−lead is carried to the cupellation
furnace, in which lead is separated from silver; of these methods I will
1
717
mention only one, because in the previous book I have explained them in
detail. Amongst us some years ago only forty−four centumpondía of silver−
lead and one of copper were melted together in the cupellation furnaces,
but now they melt forty−six centumpondía of silver−lead and one and a half
centumpondía of copper; in other places, usually a hundred and twenty
centumpondía of silver−lead alloy and six of copper are melted, in which
manner they make about one hundred and ten centumpondía more or less of
litharge and thirty of hearth−lead. But in all these methods the silver which
1
718
is in the copper is mixed with the remainder of silver; the copper itself,
equally with the lead, will be changed partly into litharge and partly into
hearth−lead. 19 The silver−lead alloy which does not melt is taken from the
margin of the crucible with a hooked bar.
The work of "drying" is distributed into four operations, which are
performed in four days. On the firstas likewise on the other three daysthe
master begins at the fourth hour of the morning, and with his assistant chips
ACAKES. BHAMMER.
off the stalactites from the exhausted liquation cakes. They then carry the
cakes to the furnace, and put the stalactites upon the heap of liquation
thorns. The head of the chipping hammer is three palms and as many digits
1
719
long; its sharp edge is a palm wide; the round end is three digits thick; the
wooden handle is four feet long.
The master throws pulverised earth into a small vessel, sprinkles water
over it, and mixes it; this he pours over the whole hearth, and sprinkles
charcoal dust over it to the thickness of a digit. If he should neglect this,
the copper, settling in the passages, would adhere to the copper bed−plates,
from which it can be chipped off only with difficulty; or else it would adhere
to the bricks, if the hearth was covered with them, and when the copper is
chipped off these they are easily broken. On the second day, at the same
time, the master arranges bricks in ten rows; in this manner twelve
passages are made. The first two rows of bricks are between the first and
the second openings on the right of the furnace; the next three rows are
between the second and third openings, the following three rows are
between the third and the fourth openings, and the last two rows between
the fourth and fifth openings. These bricks are a foot and a palm long, two
palms and a digit wide, and a palm and two digits thick; there are seven of
these thick bricks in a row, so there are seventy all together. Then on the
first three rows of bricks they lay exhausted liquation cakes and a layer five
digits thick of large charcoal; then in a similar way more exhausted
liquation cakes are laid upon the other bricks, and charcoal is thrown upon
them; in this manner seventy centumpondia of cakes are put on the
hearth of the furnace. But if half of this weight, or a little more, is to be
"dried," then four rows of bricks will suffice. Those who dry exhausted
liquation cakes 20 made from copper "bottoms" place ninety or a hundred
centumpondia 21 into the furnace at the same time. A place is left in the front
part of the furnace for the topmost cakes removed from the forehearth in
which copper is made, these being more suitable for supporting the exhausted
liquation cakes than are iron plates; indeed, if the former cakes drip copper
from the heat, this can be taken back with the liquation thorns to the first
furnace, but melted iron is of no use to us in these matters. When the cakes
of this kind have been placed in front of the exhausted liquation cakes, the
workman inserts the iron bar into the holes on the inside of the wall, which
are at a height of three palms and two digits above the hearth; the hole to
the left penetrates through into the wall, so that the bar may be pushed back
1
720
and forth. This bar is round, eight feet long and two digits in diameter;
on the right side it has a haft made of iron, which is about a foot from the
right end; the aperture in this haft is a palm wide, two digits high, and a
digit thick. The bar holds the exhausted liquation cakes opposite, lest they
should fall down. When the operation of "drying" is completed, a work−
man draws out this bar with a crook which he inserts into the haft, as I will
explain hereafter.
In order that one should understand those things of which I have spoken,
and concerning which I am about to speak, it is necessary for me to give some
information beforehand about the furnace and how it is to be made. It stands
nine feet from the fourth long wall, and as far from the wall which is between
the second and fourth transverse walls. It consists of walls, an arch, a chimney,
an interior wall, and a hearth; the two walls are at the sides; and they are
eleven feet three palms and two digits long, and where they support the
chimney they are eight feet and a palm high. At the front of the arch they
are only seven feet high; they are two feet three palms and two digits
thick, and are made either of rock or of bricks; the distance between them
is eight feet, a palm and two digits. There are two of the arches, for the
space at the rear between the walls is also arched from the ground, in order
that it may be able to support the chimney; the foundations of these
arches are the walls of the furnace; the span of the arch has the same
length as the space between the walls; the top of the arch is five feet, a palm
and two digits high. In the rear arch there is a wall made of bricks joined
with lime; this wall at a height of a foot and three palms from the ground
has five vent−holes, which are two palms and a digit high, a palm and a digit
wide, of which the first is near the right interior wall, and the last near the
left interior wall, the remaining three in the intervening space; these vent−
holes penetrate through the interior of the wall which is in the arch.
Half−bricks can be placed over the vent−holes, lest too much air should be
drawn into the furnace, and they can be taken out at times, in order that he
who is "drying" the exhausted liquation cakes may inspect the passages,
as they are called, to see whether the cakes are being properly "dried."
The front arch is three feet two palms distant from the rear one; this arch
is the same thickness as that of the rear arch, but the span is six feet wide;
1
721
ASIDE WALLS. BFRONT ARCH. CREAR ARCH. DWALL IN THE REAR ARCH.
EINNER WALL. FVENT HOLES. GCHIMNEY. HHEARTH. ITANK. KPIPE.
LPLUG. MIRON DOOR. NTRANSVERSE BARS. OUPRIGHT BARS. PPLATES.
QRINGS OF THE BARS. RCHAINS. SROWS OF BRICKS. TBAR. VITS HAFT.
XCOPPER BED−PLATES.
1
722
the interior of the a oh itself is of the same height as the walls. A chimney
is built upon the arches and the walls, and is made of bricks joined
together with lime; it is thirty−six feet high and penetrates through the
roof. The interior wall is built against the rear arch and both the side
walls, from which it juts out a foot; it is three feet and the same number
of palms high, three palms thick, and is made of bricks joined together
with lute and smeared thickly with lute, sloping up to the height of
a foot above it. This wall is a kind of shield, for it protects the exterior
walls from the heat of the fire, which is apt to injure them; the latter can−
not be easily re−made, while the former can be repaired with little work.
The hearth is made of lute, and is covered either with copper plates,
such as those of the furnaces in which silver is liquated from copper, although
they have no protuberances, or it may be covered with bricks, if the owners
are unwilling to incur the expense of copper plates. The wider part of the
hearth is made sloping in such a manner that the rear end reaches as high as
the five vent−holes, and the front end of the hearth is so low that the back
of the front arch is four feet, three palms and as many digits above it,
and the front five feet, three palms and as many digits. The hearth beyond
the furnaces is paved with bricks for a distance of six feet. Near the
furnace, against the fourth long wall, is a tank thirteen feet and a palm
long, four feet wide, and a foot and three palms deep. It is lined on all sides
with planks, lest the earth should fall into it; on one side the water flows
in through pipes, and on the other, if the plug be pulled out, it soaks into the
earth; into this tank of water are thrown the cakes of copper from which
the silver and lead have been separated. The fore part of the front furnace
arch should be partly closed with an iron door; the bottom of this door is
six feet and two digits wide; the upper part is somewhat rounded, and at
the highest point, which is in the middle, it is three feet and two palms high.
It is made of iron bars, with plates fastened to them with iron wire, there
being seven barsthree transverse and four uprighteach of which is two
digits wide and half a digit thick. The lowest transverse bar is six feet and
two palms long; the middle one has the same length; the upper one is
curved and higher at the centre, and thus longer than the other two. The
upright bars are two feet distant from one another; both the outer ones are
two feet and as many palms high; but the centre ones are three feet and two
palms. They project from the upper curved transverse bar and have holes,
in which are inserted the hooks of small chains two feet long; the topmost
links of these chains are engaged in the ring of a third chain, which, when
extended, reaches to one end of a beam which is somewhat cut out. The chain
1
723
then turns around the beam, and again hanging down, the hook in the other end
is fastened in one of the links. This beam is eleven feet long, a palm and two
digits wide, a palm thick, and turns on an iron axle fixed in a near−by timber;
the rear end of the beam has an iron pin, which is three palms and a digit long,
and which penetrates through it where it lies under a timber, and projects
from it a palm and two digits on one side, and three digits on the other side.
At this point the pin is perforated, in order that a ring may be fixed in it
1
724
and hold it, lest it should fall out of the beam; that end is hardly a digit
thick, while the other round end is thicker than a digit. When the door is
to be shut, this pin lies under the timber and holds the door so that it cannot
fall; the pin likewise prevents the rectangular iron band which encircles the
end of the beam, and into which is inserted the ring of a long hook, from
falling from the end. The lowest link of an iron chain, which is six feet long,
is inserted in the ring of a staple driven into the right wall of the furnace,
and fixed firmly by filling in with molten lead. The hook suspended at the
top from the ring should be inserted in one of these lower links, when the
door is to be raised; when the door is to be let down, the hook is taken out
of that link and put into one of the upper links.
On the third day the master sets about the principal operation. First
he throws a basketful of charcoals on to the ground in front of the hearth,
and kindles them by adding live coals, and having thrown live coals on to the
cakes placed within, he spreads them equally all over with an iron shovel.
The blade of the shovel is three palms and a digit long, and three palms wide;
its iron handle is two palms long, and the wooden one ten feet long, so that
it can reach to the rear wall of the furnace. The exhausted liquation cakes
become incandescent in an hour and a half, if the copper was good and hard,
ATHE DOOR LET DOWN. BBAR. CEXHAUSTED LIQUATION CAKES. DBRICKS.
ETONGS.
1
725
or after two hours, if it was soft and fragile. The workman adds charcoal to
them where he sees it is needed, throwing it into the furnace through the
openings on both sides between the side walls and the closed door. This open−
ing is a foot and a palm wide. He lets down the door, and when the "slags"
begin to flow he opens the passages with a bar; this should take place after
five hours; the door is let down over the upper open part of the arch for
two feet and as many digits, so that the master can bear the violence of the
heat. When the cakes shrink, charcoal should not be added to them lest
they should melt. If the cakes made from poor and fragile copper are
"dried" with cakes made from good hard copper, very often the copper
so settles into the passages that a bar thrust into them cannot penetrate
them. This bar is of iron, six feet and two palms long, into which a wooden
handle five feet long is inserted. The refiner draws off the "slags" with a
rabble from the right side of the hearth. The blade of the rabble is made
of an iron plate a foot and a palm wide, gradually narrowing toward the
handle; the blade is two palms high, its iron handle is two feet long, and
the wooden handle set into it is ten feet long.
When the exhausted liquation cakes have been "dried," the master
ATHE DOOR RAISED. BHOOKED BAR. CTWO−PRONGED RAKE. DTONGS.
ETANK.
1
726
raises the door in the manner I have described, and with a long iron hook
inserted into the haft of the bar he draws it through the hole in the left wall
from the hole in the right wall; afterward he pushes it back and replaces it.
The master then takes out the exhausted liquation cakes nearest to him with
the iron hook; then he pulls out the cakes from the bricks. This hook is
two palms high, as many digits wide, and one thick; its iron handle is two
feet long, and the wooden handle eleven feet long. There is also a two−
pronged rake with which the "dried" cakes are drawn over to the left side so
that they may be seized with tongs; the prongs of the rake are pointed,
and are two palms long, as many digits wide, and one digit thick; the iron
part of the handle is a foot long, the wooden part nine feet long. The
"dried" cakes, taken out of the hearth by the master and his assistants,
are seized with other tongs and thrown into the rectangular tank, which is
almost filled with water. These tongs are two feet and three palms long,
both the handles are round and more than a digit thick, and the ends are
bent for a palm and two digits; both the jaws are a digit and a half wide
in front and sharpened; at the back they are a digit thick, and then gradually
taper, and when closed, the interior is two palms and as many digits wide.
The "dried" cakes which are dripping copper are not immediately dipped
into the tank, because, if so, they burst in fragments and give out a sound
like thunder. The cakes are afterward taken out of the tank with the
tongs, and laid upon the two transverse planks on which the workmen stand;
the sooner they are taken out the easier it is to chip off the copper that
has become ash−coloured. Finally, the master, with a spade, raises up the
bricks a little from the hearth, while they are still warm. The blade of the
spade is a palm and two digits long, the lower edge is sharp, and is a palm
and a digit wide, the upper end a palm wide; its handle is round, the iron
part being two feet long, and the wooden part seven and a half feet long.
On the fourth day the master draws out the liquation thorns which
have settled in the passages; they are much richer in silver than those
that are made when the silver−lead is liquated from copper in the liquation
furnace. The "dried" cakes drip but little copper, but nearly all their
remaining silver−lead and the thorns consist of it, for, indeed, in one
centumpondium of "dried" copper there should remain only half an uncía
of silver, and there sometimes remain only three drachmae. 22 Some smelters
chip off the metal adhering to the bricks with a hammer, in order that it
may be melted again; others, however, crush the bricks under the stamps
and wash them, and the copper and lead thus collected is melted again. The
1
727
master, when he has taken these things away and put them in their places,
has finished his day' s work.
The assistants take the "dried" cakes out of the tank on the
next day, place them on an oak block, and first pound them with rounded
hammers in order that the ash−coloured copper may fall away from them,
1
728
and then they dig out with pointed picks the holes in the cakes, which contain
the same kind of copper. The head of the round hammer is three palms and
a digit long; one end of the head is round and two digits long and thick;
the other end is chisel−shaped, and is two digits and a half long. The sharp
pointed hammer is the same length as the round hammer, but one end is
pointed, the other end is square, and gradually tapers to a point.
ATANK. BBOARD. CTONGS. D"DRIED" CAKES TAKEN OUT OF THE TANKS.
EBLOCK. FROUNDED HAMMER. GPOINTED HAMMER.
The nature of copper is such that when it is "dried" it becomes ash
coloured, and since this copper contains silver, it is smelted again in the
blast furnaces. 23
I have described sufficiently the method by which exhausted liquation
cakes are "dried"; now I will speak of the method by which they are made
into copper after they have been "dried." These cakes, in order that
they may recover the appearance of copper which they have to some extent
lost, are melted in four furnaces, which are placed against the second long
wall in the part of the building between the second and third transverse
walls. This space is sixty−three feet and two palms long, and since each of
1
729
these furnaces occupies thirteen feet, the space which is on the right
side of the first furnace, and on the left of the fourth, are each three feet and
three palms wide, and the distance between the second and third furnace is
six feet. In the middle of each of these three spaces is a door, a foot and
a half wide and six feet high, and the middle one is common to the master
of each of the furnaces. Each furnace has its own chimney, which rises
between the two long walls mentioned above, and is supported by two arches
and a partition wall. The partition wall is between the two furnaces, and
is five feet long, ten feet high, and two feet thick; in front of it is a pillar
belonging in common to the front arches of the furnace on either side, which
is two feet and as many palms thick, three feet and a half wide. The front
arch reaches from this common pillar to another pillar that is common to the
side arch of the same furnace; this arch on the right spans from the second
long wall to the same pillar, which is two feet and as many palms wide and
thick at the bottom. The interior of the front arch is nine feet and a palm
wide, and eight feet high at its highest point; the interior of the arch which
is on the right side, is five feet and a palm wide, and of equal height to the
other, and both the arches are built of the same height as the partition wall.
Imposed upon these arches and the partition wall are the walls of the chimney;
these slope upward, and thus contract, so that at the upper part, where the
fumes are emitted, the opening is eight feet in length, one foot and three
palms in width. The fourth wall of the chimney is built vertically upon the
second long wall. As the partition wall is common to the two furnaces, so its
superstructure is common to the two chimneys. In this sensible manner
the chimney is built. At the front each furnace is six feet two palms long,
and three feet two palms wide, and a cubit high; the back of each furnace
is against the second long wall, the front being open. The first furnace is open
and sloping at the right side, so that the slags may be drawn out; the left
side is against the partition wall, and has a little wall built of bricks cemented
together with lute; this little wall protects the partition wall from injury by
the fire. On the contrary, the second furnace has the left side open and
the right side is against the partition wall, where also it has its own little wall
which protects the partition wall from the fire. The front of each furnace is
built of rectangular rocks; the interior of it is filled up with earth. Then in
each of the furnaces at the rear, against the second long wall, is an aperture
through an arch at the back, and in these are fixed the copper pipes. Each
furnace has a round pit, two feet and as many palms wide, built three feet
away from the partition wall. Finally, under the pit of the furnace, at a
depth of a cubit, is the hidden receptacle for moisture, similar to the others,
whose vent penetrates through the second long wall and slopes upward to
1
730
the right from the first furnace, and to the left from the second. If copper
is to be made the next day, then the master cuts out the crucible with a
spatula, the blade of which is three digits wide and as many palms long, the
iron handle being two feet long and one and a half digits in diameter; the
wooden handle inserted into it is round, five feet long and two digits
in diameter. Then, with another cutting spatula, he makes the crucible
1
731
smooth; the blade of this spatula is a palm wide and two palms long; its
handle, partly of iron, partly of wood, is similar in every respect to the first
one. Afterward he throws pulverised clay and charcoal into the crucible, pours
water over it, and sweeps it over with a broom into which a stick is fixed.
Then immediately he throws into the crucible a powder, made of two
wheelbarrowsful of sifted charcoal dust, as many wheelbarrowsful of
AHEARTH OF THE FURNACE. BCHIMNEY. CCOMMON PILLAR. DOTHER PILLARS.
THE PARTITION WALL IS BEHIND THE COMMON PILLAR AND NOT TO BE SEEN. EARCHES.
FLITTLE WALLS WHICH PROTECT THE PARTITION WALL FROM INJURY BY THE FIRE.
GCRUCIBLES. HSECOND LONG WALL. IDOOR. KSPATULA. LTHE OTHER
SPATULA. MTHE BROOM IN WHICH IS INSERTED A STICK. NPESTLES. OWOODEN
MALLET. PPLATE. QSTONES. RIRON ROD.
pulverised clay likewise sifted, and six basketsful of river sand which has
passed through a very fine sieve. This powder, like that used by smelters,
is sprinkled with water and moistened before it is put into the crucible, so
that it may be fashioned by the hands into shapes similar to snowballs.
When it has been put in, the master first kneads it and makes it smooth with
his hands, and then pounds it with two wooden pestles, each of which is a
cubit long; each pestle has a round head at each end, but one of these is
a palm in diameter, the other three digits; both are thinner in the middle,
so that they may be held in the hand. Then he again throws moistened
1
732
powder into the crucible, and again makes it smooth with his hands, and
kneads it with his fists and with the pestles; then, pushing upward and
pressing with his fingers, he makes the edge of the crucible smooth. After the
crucible has been made smooth, he sprinkles in dry charcoal dust, and again
pounds it with the same pestles, at first with the narrow heads, and afterward
with the wider ones. Then he pounds the crucible with a wooden mallet
two feet long, both heads of which are round and three digits in diameter;
its wooden handle is two palms long, and one and a half digits in diameter.
Finally, he throws into the crucible as much pure sifted ashes as both hands
can hold, and pours water into it, and, taking an old linen rag, he smears
the crucible over with the wet ashes. The crucible is round and sloping. If
copper is to be made from the best quality of "dried" cakes, it is made two
feet wide and one deep, but if from other cakes, it is made a cubit wide and
two palms deep. The master also has an iron band curved at both ends,
two palms long and as many digits wide, and with this he cuts off the edges
of the crucible if they are higher than is necessary. The copper pipe is
inclined, and projects three digits from the wall, and has its upper end and
both sides smeared thick with lute, that it may not be burned; but the under−
side of the pipe is smeared thinly with lute, for this side reaches almost to the
edge of the crucible, and when the crucible is full the molten copper touches
it. The wall above the pipe is smeared over with lute, lest that should be
damaged. He does the same to the other side of an iron plate, which is a
foot and three palms long and a foot high; this stands on stones near the
crucible at the side where the hearth slopes, in order that the slag may run
out under it. Others do not place the plates upon stones, but cut out
of the plate underneath a small piece, three digits long and three digits
wide; lest the plate should fall, it is supported by an iron rod fixed in the
wall at a height of two palms and the same number of digits, and it projects
from the wall three palms.
Then with an iron shovel, whose wooden handle is six feet long, he
throws live charcoal into the crucible; or else charcoal, kindled by means
of a few live coals, is added to them. Over the live charcoal he lays "dried"
cakes, which, if they were of copper of the first quality, weigh all together
three centumpondia, or three and a half centumpondía; but if they were
of copper of the second quality, then two and a half centumpondía; if they
were of the third quality, then two centumpondía only; but if they were
of copper of very superior quality, then they place upon it six centumpondía,
and in this case they make the crucible wider and deeper. 24 The lowest
"dried" cake is placed at a distance of two palms from the pipe, the rest at
1
733
a greater distance, and when the lower ones are melted the upper ones fall
down and get nearer to the pipe; if they do not fall down they must
be pushed with a shovel. The blade of the shovel is a foot long, three palms
and two digits wide, the iron part of the handle is two palms long, the
1
734
wooden part nine feet. Round about the "dried" cakes are placed large
long pieces of charcoal, and in the pipe are placed medium−sized pieces.
When all these things have been arranged in this manner, the fire must be
more violently excited by the blast from the bellows. When the copper is
melting and the coals blaze, the master pushes an iron bar into the middle
of them in order that they may receive the air, and that the flame can force
its way out. This pointed bar is two and a half feet long, and its wooden
handle four feet long. When the cakes are partly melted, the master, passing
out through the door, inspects the crucible through the bronze pipe, and if he
should find that too much of the "slag" is adhering to the mouth of the pipe,
and thus impeding the blast of the bellows, he inserts the hooked iron bar
into the pipe through the nozzle of the bellows, and, turning this about the
mouth of the pipe, he removes the "slags" from it. The hook on this bar
is two digits high; the iron part of the handle is three feet long; the wooden
part is the same number of palms long. Now it is time to insert the bar
under the iron plate, in order that the "slags" may flow out. When the
cakes, being all melted, have run into the crucible, he takes out a sample of
copper with the third round bar, which is made wholly of iron, and is three feet
long, a digit thick, and has a steel point lest its pores should absorb the copper.
APOINTED BAR. BTHIN COPPER LAYER. CANVIL. DHAMMER.
1
735
When he has compressed the bellows, he introduces this bar as quickly as
possible into the crucible through the pipe between the two nozzles, and
takes out samples two, three, or four times, until he finds that the copper is
perfectly refined. If the copper is good it adheres easily to the bar, and
two samples suffice; if it is not good, then many are required. It is
necessary to smelt it in the crucible until the copper adhering to the bar is
seen to be of a brassy colour, and if the upper as well as the lower part of
the thin layer of copper may be easily broken, it signifies that the copper
is perfectly melted; he places the point of the bar on a small iron anvil,
and chips off the thin layer of copper from it with a hammer. 25
If the copper is not good, the master draws off the "slags" twice, or
three times if necessarythe first time when some of the cakes have been
melted, the second when all have melted, the third time when the copper has
been heated for some time. If the copper was of good quality, the "slags"
are not drawn off before the operation is finished, but at the time they are to be
drawn off, he depresses the bar over both bellows, and places over both a
stick, a cubit long and a palm wide, half cut away at the upper part, so that it
may pass under the iron pin fixed at the back in the perforated wood. This
he does likewise when the copper has been completely melted. Then the
assistant removes the iron plate with the tongs; these tongs are four feet
three palms long, their jaws are about a foot in length, and their straight part
measures two palms and three digits, and the curved a palm and a digit.
The same assistant, with the iron shovel, throws and heaps up the larger
pieces of charcoal into that part of the hearth which is against the little wall
which protects the other wall from injury by fire, and partly extinguishes
them by pouring water over them. The master, with a hazel stick inserted
1
736
into the crucible, stirs it twice. Afterward he draws off the slags with a
rabble, which consists of an iron blade, wide and sharp, and of alder−wood;
the blade is a digit and a half in width and three feet long; the wooden handle
inserted in its hollow part is the same number of feet long, and the alder−wood
in which the blade is fixed must have the figure of a rhombus; it must be
three palms and a digit long, a palm and two digits wide, and a palm thick.
Subsequently he takes a broom and sweeps the charcoal dust and small coal
over the whole of the crucible, lest the copper should cool before it flows
together; then, with a third rabble, he cuts off the slags which may adhere
to the edge of the crucible. The blade of this rabble is two palms long and
a palm and one digit wide, the iron part of the handle is a foot and three palms
long, the wooden part six feet. Afterward he again draws off the slags
from the crucible, which the assistant does not quench by pouring water
upon them, as the other slags are usually quenched, but he sprinkles over
them a little water and allows them to cool. If the copper should bubble,
he presses down the bubbles with the rabble. Then he pours water on the wall
and the pipes, that it may flow down warm into the crucible, for, the
copper, if cold water were to be poured over it while still hot, would spatter
about. If a stone, or a piece of lute or wood, or a damp coal should then fall
into it, the crucible would vomit out all the copper with a loud noise like
thunder, and whatever it touches it injures and sets on fire. Subsequently he
lays a curved board with a notch in it over the front part of the crucible; it
is two feet long, a palm and two digits wide, and a digit thick. Then
the copper in the crucible should be divided into cakes with an iron wedge−
shaped bar; this is three feet long, two digits wide, and steeled on the end
for the distance of two digits, and its wooden handle is three feet long. He
places this bar on the notched board, and, driving it into the copper, moves
1
737
ACRUCIBLE. BBOARD. CWEDGE−SHAPED BAR. DCAKES OF COPPER MADE BY
SEPARATING THEM WITH THE WEDGE−SHAPED BAR. ETONGS. FTUB.
1
738
it forward and back, and by this means the water flows into the vacant
space in the copper, and he separates the cake from the rest of the mass.
If the copper is not perfectly smelted the cakes will be too thick, and can−
not be taken out of the crucible easily. Each cake is afterward seized by
the assistant with the tongs and plunged into the water in the tub; the first
one is placed aside so that the master may re−melt it again immediately, for,
since some "slags" adhere to it, it is not as perfect as the subsequent ones;
indeed, if the copper is not of good quality, he places the first two cakes aside.
Then, again pouring water over the wall and the pipes, he separates out the
second cake, which the assistant likewise immerses in water and places on
the ground together with the others separated out in the same way, which
he piles upon them. These, if the copper was of good quality, should be
thirteen or more in number; if it was not of good quality, then fewer. If the
copper was of good quality, this part of the operation, which indeed is dis−
tributed into four parts, is accomplished by the master in two hours; if of
mediocre quality, in two and a half hours; if of bad quality, in three. The
"dried" cakes are re−melted, first in the first crucible and then in the
second. The assistant must, as quickly as possible, quench all the cakes
with water, after they have been cut out of the second crucible. Afterward
with the tongs he replaces in its proper place the iron plate which was in front
of the furnace, and throws the charcoal back into the crucible with a shovel.
Meanwhile the master, continuing his work, removes the wooden stick from
the bars of the bellows, so that in re−melting the other cakes he may accom−
plish the third part of his process; this must be carefully done, for if a particle
from any iron implement should by chance fall into the crucible, or should
be thrown in by any malevolent person, the copper could not be made until
the iron had been consumed, and therefore double labour would have to be
expended upon it. Finally, the assistant extinguishes all the glowing coals,
and chips off the dry lute from the mouth of the copper pipe with a hammer;
one end of this hammer is pointed, the other round, and it has a wooden handle
five feet long. Because there is danger that the copper would be scattered if
the pompholyx and spodos, which adhere to the walls and the hood erected
upon them, should fall into the crucible, he cleans them off in the meantime.
Every week he takes the copper flowers out of the tub, after having poured off
the water, for these fall into it from the cakes when they are quenched. 26
1
739
The bellows which this master uses differ in size from the others, for the
boards are seven and a half feet long; the back part is three feet wide;
the front, where the head is joined on is a foot, two palms and as many digits.
The head is a cubit and a digit long; the back part of it is a cubit and a
palm wide, and then becomes gradually narrower. The nozzles of the bellows
are bound together by means of an iron chain, controlled by a thick
bar, one end of which penetrates into the ground against the back of the long
wall, and the other end passes under the beam which is laid upon the
foremost perforated beams. These nozzles are so placed in a copper pipe
that they are at a distance of a palm from the mouth; the mouth should be
made three digits in diameter, that the air may be violently expelled through
this narrow aperture.
There now remain the liquation thorns, the ash−coloured copper, the
"slags," and the cadmía. 27 Liquation cakes are made from thorns in the
following manner. 28 There are taken three−quarters of a centumpondium of
thorns, which have their origin from the cakes of copper−lead alloy when
lead−silver is liquated, and as many parts of a centumpondíum of the thorns
derived from cakes made from once re−melted thorns by the same method,
and to them are added a centumpondíum of de−silverized lead and half a
centumpondíum of hearth−lead. If there is in the works plenty of litharge, it
is substituted for the de−silverized lead. One and a half centumpondía of
litharge and hearth−lead is added to the same weight of primary thorns,
and half a centumpondíum of thorns which have their origin from liquation
cakes composed of thorns twice re−melted by the same method (tertiary
thorns), and a fourth part of a centumpondíum of thorns which are pro−
1
740
duced when the exhausted liquation cakes are "dried." By both methods
one single liquation cake is made from three centumpondia. In this manner
the smelter makes every day fifteen liquation cakes, more or less; he takes
great care that the metallic substances, from which the first liquation cake is
made, flow down properly and in due order into the fore−hearth, before the
material of which the subsequent cake is to be made. Five of these liquation
cakes are put simultaneously into the furnace in which silver−lead is liquated
from copper, they weigh almost fourteen centumpondía, and the "slags"
made therefrom usually weigh quite a centumpondium. In all the liquation
cakes together there is usually one líbra and nearly two uncíae of silver, and
in the silver−lead which drips from those cakes, and weighs seven and a half
centumpondía, there is in each an uncia and a half of silver. In each of the
three centumpondia of liquation thorns there is almost an uncia of silver, and
in the two centumpondia and a quarter of exhausted liquation cakes there
is altogether one and a half unciae; yet this varies greatly for each variety of
thorns, for in the thorns produced from primary liquation cakes made of
copper and lead when silver−lead is liquated from the copper, and those
produced in "drying" the exhausted liquation cakes, there are almost two
uncíae of silver; in the others not quite an uncía. There are other thorns
besides, of which I will speak a little further on.
Those in the Carpathian Mountains who make liquation cakes from the
copper "bottoms" which remain after the upper part of the copper is
divided from the lower, in the furnace similar to an oven, produce thorns when
the poor or mediocre silver−lead is liquated from the copper. These, together
with those made of cakes of re−melted thorns, or made with re−melted litharge,
are placed in a heap by themselves; but those that are made from cakes
melted from hearth−lead are placed in a heap separate from the first, and
likewise those produced from "drying" the exhausted liquation cakes are
placed separately; from these thorns liquation cakes are made. From the
first heap they take the fourth part of a centumpondíum, from the second
the same amount, from the third a centumpondíum, to which thorns are
added one and a half centumpondía of litharge and half a centumpondíum of
hearth−lead, and from these, melted in the blast furnace, a liquation cake is
made; each workman makes twenty such cakes every day. But of theirs
enough has been said for the present; I will return to ours.
The ash−coloured copper 29 which is chipped off, as I have stated, from
the "dried" cakes, used some years ago to be mixed with the thorns produced
from liquation of the copper−lead alloy, and contained in themselves, equally
1
741
with the first, two uncíae of silver; but now it is mixed with the concentrates
washed from the accretions and the other material. The inhabitants of the
Carpathian Mountains melt this kind of copper in furnaces in which are re−
melted the "slags" which flow out when the copper is refined; but as this
soon melts and flows down out of the furnace, two workmen are required for
1
742
the work of smelting, one of whom smelts, while the other takes out the
thick cakes from the forehearth. These cakes are only "dried," and from
the "dried" cakes copper is again made.
The "slags" 30 are melted continually day and night, whether they have
been drawn off from the alloyed metals with a rabble, or whether they adhered
to the forehearth to the thickness of a digit and made it smaller and
were taken off with spatulas. In this manner two or three liquation cakes
are made, and afterward much or little of the "slag," skimmed from the
molten alloy of copper and lead, is re−melted. Such liquation cakes should
weigh up to three centumpondia, in each of which there is half an uncia of
silver. Five cakes are placed at the same time in the furnace in which
argentiferous lead is liquated from copper, and from these are made lead
which contains half an uncia of silver to the centumpondium. The exhausted
liquation cakes are laid upon the other baser exhausted liquation cakes, from
both of which yellow copper is made. The base thorns thus obtained are
re−melted with a few baser "slags," after having been sprinkled with con−
centrates from furnace accretions and other material, and in this manner six
or seven liquation cakes are made, each of which weighs some two centum−
pondia. Five of these are placed at the same time in the furnace in which
silver−lead is liquated from copper; these drip three centumpondia of
lead, each of which contains half an uncia of silver. The basest thorns
thus produced should be re−melted with only a little "slag." The copper
alloyed with lead, which flows down from the furnace into the fore−
hearth, is poured out with a ladle into oblong copper moulds; these cakes
are "dried" with base exhausted liquation cakes. The thorns they produce
are added to the base thorns, and they are made into cakes according to the
method I have described. From the "dried" cakes they make copper, of
which some add a small portion to the best "dried" cakes when copper is
made from them, in order that by mixing the base copper with the good it
may be sold without loss. The "slags," if they are utilisable, are re−melted
a second and a third time, the cakes made from them are "dried," and from
the "dried" cakes is made copper, which is mixed with the good copper. The
"slags," drawn off by the master who makes copper out of "dried" cakes,
are sifted, and those which fall through the sieve into a vessel placed under−
neath are washed; those which remain in it are emptied into a wheelbarrow
and wheeled away to the blast furnaces, and they are re−melted together
with other "slags," over which are sprinkled the concentrates from washing
the slags or furnace accretions made at this time. The copper which flows out
1
743
of the furnace into the forehearth, is likewise dipped out with a ladle into
oblong copper moulds; in this way nine or ten cakes are made, which are
"dried," together with bad exhausted liquation cakes, and from these
"dried" cakes yellow 31 copper is made.
The cadmia, 32 as it is called by us, is made from the "slags" which the
master, who makes copper from "dried" cakes, draws off together with other
re−melted base "slags"; for, indeed, if the copper cakes made from such
"slags" are broken, the fragments are called cadmia; from this and yellow
copper is made caldarium copper in two ways. For either two parts of cadmia
are mixed with one of yellow copper in the blast furnaces, and melted; or, on
the contrary, two parts of yellow copper with one of cadmia, so that the
cadmía and yellow copper may be well mixed; and the copper which flows down
from the furnace into the forehearth is poured out with a ladle into oblong
copper moulds heated beforehand. These moulds are sprinkled over with char−
coal dust before the caldarium copper is to be poured into them, and the same
dust is sprinkled over the copper when it is poured in, lest the cadmia and
yellow copper should freeze before they have become well mixed. With a
piece of wood the assistant cleanses each cake from the dust, when it is
turned out of the mould. Then he throws it into the tub containing hot water,
for the caldarium copper is finer if quenched in hot water. But as I have
so often made mention of the oblong copper moulds, I must now speak of
them a little; they are a foot and a palm long, the inside is three palms and a
digit wide at the top, and they are rounded at the bottom.
The concentrates are of two kindsprecious and base. 33 The first are
obtained from the accretions of the blast furnace, when liquation cakes are
made from copper and lead, or from precious liquation thorns, or from the
better quality "slags," or from the best grade of concentrates, or from the
sweepings and bricks of the furnaces in which exhausted liquation cakes are
"dried"; all of these things are crushed and washed, as I explained in Book
VIII. The base concentrates are made from accretions formed when cakes
are cast from base thorns or from the worst quality of slags. The smelter
who makes liquation cakes from the precious concentrates, adds to them
three wheelbarrowsful of litharge and four barrowsful of hearth−lead and
one of ash−coloured copper, from all of which nine or ten liquation cakes
are melted out, of which five at a time are placed in the furnace in which
silver−lead is liquated from copper; a centumpondium of the lead which drips
from these cakes contains one uncia of silver. The liquation thorns are
1
744
AFURNACE. BFOREHEARTH. COBLONG MOULDS.
placed apart by themselves, of which one basketful is mixed with the precious
thorns to be re−melted. The exhausted liquation cakes are "dried" at the
same time as other good exhausted liquation cakes.
The thorns which are drawn off from the lead, when it is separated from
silver in the cupellation furnace 34 , and the hearth−lead which remains in the
crucible in the middle part of the furnaces, together with the hearth material
which has become defective and has absorbed silver−lead, are all melted
together with a little slag in the blast furnaces. The lead, or rather the
silver−lead, which flows from the furnace into the fore−hearth, is poured out
into copper moulds such as are used by the refiners; a centumpondium of
such lead contains four uncíae of silver, or, if the hearth was defective, it
contains more. A small portion of this material is added to the copper and
lead when liquation cakes are made from them, if more were to be added
the alloy would be much richer than it should be, for which reason the wise
1
745
foreman of the works mixes these thorns with other precious thorns. The
hearth−lead which remains in the middle of the crucible, and the hearth
material which absorbs silver−lead, is mixed with other hearth−lead which
remains in the cupellation furnace crucible; and yet some cakes, made rich
in this manner, may be placed again in the cupellation furnaces, together
with the rest of the silver−lead cakes which the refiner has made.
The inhabitants of the Carpathian Mountains, if they have an abundance
of finely crushed copper 35 or lead either made from "slags," or collected
from the furnace in which the exhausted liquation cakes are dried, or
litharge, alloy them in various ways. The "first" alloy consists of two
centumpondia of lead melted out of thorns, litharge, and thorns made
from hearth−lead, and of half a centumpondium each of lead collected in
the furnace in which exhausted liquation cakes are "dried," and of copper
mínutum, and from these are made liquation cakes; the task of the smelter is
finished when he has made forty liquation cakes of this kind. The
"second" alloy consists of two centumpondia of litharge, of one and a
quarter centumpondia of de−silverized lead or lead from "slags," and of half
a centumpondium of lead made from thorns, and of as much copper minutum.
The "third" alloy consists of three centumpondía of litharge and of half a
centumpondium each of de−silverized lead, of lead made from thorns, and of
copper mínutum contusum. Liquation cakes are made from all these alloys; the
task of the smelters is finished when they have made thirty cakes.
The process by which cakes are made among the Tyrolese, from which
they separate the silver−lead, I have explained in Book IX.
Silver is separated from iron in the following manner. Equal portions of
iron scales and filings and of stibium are thrown into an earthenware crucible
which, when covered with a lid and sealed, is placed in a furnace, into
which air is blown. When this has melted and again cooled, the crucible
is broken; the button that settles in the bottom of it, when taken out,
is pounded to powder, and the same weight of lead being added, is mixed
and melted in a second crucible; at last this button is placed in a cupel
and the lead is separated from the silver. 36
There are a great variety of methods by which one metal is separated
from other metals, and the manner in which the same are alloyed I have
explained partly in the eighth book of De Natura Fossilium, and partly I will
explain elsewhere. Now I will proceed to the remainder of my subject.
1
746
END OF BOOK XI.