Some of the Lusitanians melt tin from tin-stone in small furnaces. They

use round bellows made of leather, of which the fore end is a round iron

disc and the rear end a disc of wood; in a hole in the former is fixed

the nozzle, in the middle of the latter the blow-hole. Above this is the

handle or haft, which draws open the round bellows and lets in the air,

or compresses it and drives the air out. Between the discs are several

iron hoops to which the leather is fastened, making such folds as are to

be seen in paper lanterns that are folded together. Since this kind of

bellows does not give a vigorous blast, because they are drawn apart and

compressed slowly, the smelter is not able during a whole day to smelt

much more than half a _centumpondium_ of tin.

[Illustration 422 (Iron smelting Furnaces): A--Hearth. B--Heap.

C--Slag-vent. D--Iron mass. E--Wooden mallets. F--Hammer. G--Anvil.]

Very good iron ore is smelted[55] in a furnace almost like the

cupellation furnace. The hearth is three and a half feet high, and five

feet long and wide; in the centre of it is a crucible a foot deep and

one and a half feet wide, but it may be deeper or shallower, wider or

narrower, according to whether more or less ore is to be made into iron.

A certain quantity of iron ore is given to the master, out of which he

may smelt either much or little iron. He being about to expend his skill

and labour on this matter, first throws charcoal into the crucible, and

sprinkles over it an iron shovel-ful of crushed iron ore mixed with

unslaked lime. Then he repeatedly throws on charcoal and sprinkles it

with ore, and continues this until he has slowly built up a heap; it

melts when the charcoal has been kindled and the fire violently

stimulated by the blast of the bellows, which are skilfully fixed in a

pipe. He is able to complete this work sometimes in eight hours,

sometimes in ten; and again sometimes in twelve. In order that the heat

of the fire should not burn his face, he covers it entirely with a cap,

in which, however, there are holes through which he may see and breathe.

At the side of the hearth is a bar which he raises as often as is

necessary, when the bellows blow too violent a blast, or when he adds

more ore and charcoal. He also uses the bar to draw off the slags, or to

open or close the gates of the sluice, through which the waters flow

down on to the wheel which turns the axle that compresses the bellows.

In this sensible way, iron is melted out and a mass weighing two or

three _centumpondia_ may be made, providing the iron ore was rich. When

this is done the master opens the slag-vent with the tapping-bar, and

when all has run out he allows the iron mass to cool. Afterward he and

his assistant stir the iron with the bar, and then in order to chip off

the slags which had until then adhered to it, and to condense and

flatten it, they take it down from the furnace to the floor, and beat it

with large wooden mallets having slender handles five feet long.

Thereupon it is immediately placed on the anvil, and repeatedly beaten

by the large iron hammer that is raised by the cams of an axle turned by

a water-wheel. Not long afterward it is taken up with tongs and placed

under the same hammer, and cut up with a sharp iron into four, five, or

six pieces, according to whether it is large or small. These pieces,

after they have been re-heated in the blacksmith's forge and again

placed on the anvil, are shaped by the smith into square bars or into

ploughshares or tyres, but mainly into bars. Four, six, or eight of

these bars weigh one-fifth of a _centumpondium_, and from these they

make various implements. During the blows from the hammer by which it is

shaped by the smith, a youth pours water with a ladle on to the glowing

iron, and this is why the blows make such a loud sound that they may be

heard a long distance from the works. The masses, if they remain and

settle in the crucible of the furnace in which the iron is smelted,

become hard iron which can only be hammered with difficulty, and from

these they make the iron-shod heads for the stamps, and such-like very

hard articles.

[Illustration 424 (Iron smelting Furnaces): A--Furnace. B--Stairs.

C--Ore. D--Charcoal.]

But to iron ore which is cupriferous, or which when heated[56] melts

with difficulty, it is necessary for us to give a fiercer fire and more

labour; because not only must we separate the parts of it in which there

is metal from those in which there is no metal, and break it up by dry

stamps, but we must also roast it, so that the other metals and noxious

juices may be exhaled; and we must wash it, so that the lighter parts

may be separated from it. Such ores are smelted in a furnace similar to

the blast furnace, but much wider and higher, so that it may hold a

great quantity of ore and much charcoal; mounting the stairs at the side

of the furnace, the smelters fill it partly with fragments of ore not

larger than nuts, and partly with charcoal; and from this kind of ore

once or twice smelted they make iron which is suitable for re-heating in

the blacksmith's forge, after it is flattened out with the large iron

hammer and cut into pieces with the sharp iron.

[Illustration 425 (Steel making Furnaces): A--Forge. B--Bellows.

C--Tongs. D--Hammer. E--Cold stream.]

By skill with fire and fluxes is made that kind of iron from which steel

is made, which the Greeks call [Greek: stomoma]. Iron should be selected

which is easy to melt, is hard and malleable. Now although iron may be

smelted from ore which contains other metals, yet it is then either soft

or brittle; such (iron) must be broken up into small pieces when it is

hot, and then mixed with crushed stone which melts. Then a crucible is

made in the hearth of the smith's furnace, from the same moistened

powder from which are made the forehearths in front of the furnaces in

which ores of gold or silver are smelted; the width of this crucible is

about one and a half feet and the depth one foot. The bellows are so

placed that the blast may be blown through the nozzle into the middle of

the crucible. Then the whole of the crucible is filled with the best

charcoal, and it is surrounded by fragments of rock to hold in place the

pieces of iron and the superimposed charcoal. As soon as all the

charcoal is kindled and the crucible is glowing, a blast is blown from

the bellows and the master pours in gradually as much of the mixture of

iron and flux as he wishes. Into the middle of this, when it is melted,

he puts four iron masses each weighing thirty pounds, and heats them for

five or six hours in a fierce fire; he frequently stirs the melted iron

with a bar, so that the small pores in each mass absorb the minute

particles, and these particles by their own strength consume and expand

the thick particles of the masses, which they render soft and similar to

dough. Afterward the master, aided by his assistant, takes out a mass

with the tongs and places it on the anvil, where it is pounded by the

hammer which is alternately raised and dropped by means of the

water-wheel; then, without delay, while it is still hot, he throws it

into water and tempers it; when it is tempered, he places it again on

the anvil, and breaks it with a blow from the same hammer. Then at once

examining the fragments, he decides whether the iron in some part or

other, or as a whole, appears to be dense and changed into steel; if so,

he seizes one mass after another with the tongs, and taking them out he

breaks them into pieces. Afterward he heats the mixture up again, and

adds a portion afresh to take the place of that which has been absorbed

by the masses. This restores the energy of that which is left, and the

pieces of the masses are again put back into the crucible and made

purer. Each of these, after having been heated, is seized with the

tongs, put under the hammer and shaped into a bar. While they are still

glowing, he at once throws them into the very coldest nearby running

water, and in this manner, being suddenly condensed, they are changed

into pure steel, which is much harder and whiter than iron.

The ores of the other metals are not smelted in furnaces. Quicksilver

ores and also antimony are melted in pots, and bismuth in troughs.

[Illustration 427 (Quicksilver distillation Furnaces): A--Hearth.

B--Poles. C--Hearth without fire in which the pots are placed. D--Rocks.

E--Rows of pots. F--Upper pots. G--Lower pots.]

I will first speak of quicksilver. This is collected when found in pools

formed from the outpourings of the veins and stringers; it is cleansed

with vinegar and salt, and then it is poured into canvas or soft

leather, through which, when squeezed and compressed, the quicksilver

runs out into a pot or pan. The ore of quicksilver is reduced in double

or single pots. If in double pots, then the upper one is of a shape not

very dissimilar to the glass ampullas used by doctors, but they taper

downward toward the bottom, and the lower ones are little pots similar

to those in which men and women make cheese, but both are larger than

these; it is necessary to sink the lower pots up to the rims in earth,

sand, or ashes. The ore, broken up into small pieces is put into the

upper pots; these having been entirely closed up with moss, are placed

upside down in the openings of the lower pots, where they are joined

with lute, lest the quicksilver which takes refuge in them should be

exhaled. There are some who, after the pots have been buried, do not

fear to leave them uncemented, and who boast that they are able to

produce no less weight of quicksilver than those who do cement them, but

nevertheless cementing with lute is the greatest protection against

exhalation. In this manner seven hundred pairs of pots are set together

in the ground or on a hearth. They must be surrounded on all sides with

a mixture consisting of crushed earth and charcoal, in such a way that

the upper pots protrude to a height of a palm above it. On both sides of

the hearth rocks are first laid, and upon them poles, across which the

workmen place other poles transversely; these poles do not touch the

pots, nevertheless the fire heats the quicksilver, which fleeing from

the heat is forced to run down through the moss into the lower pots. If

the ore is being reduced in the upper pots, it flees from them, wherever

there is an exit, into the lower pots, but if the ore on the contrary is

put in the lower pots the quicksilver rises into the upper pot or into

the operculum, which, together with the gourd-shaped vessels, are

cemented to the upper pots.

The pots, lest they should become defective, are moulded from the best

potters' clay, for if there are defects the quicksilver flies out in the

fumes. If the fumes give out a very sweet odour it indicates that the

quicksilver is being lost, and since this loosens the teeth, the

smelters and others standing by, warned of the evil, turn their backs to

the wind, which drives the fumes in the opposite direction; for this

reason, the building should be open around the front and the sides, and

exposed to the wind. If these pots are made of cast copper they last a

long time in the fire. This process for reducing the ores of quicksilver

is used by most people.

In a similar manner the antimony ore,[57] if free from other metals, is

reduced in upper pots which are twice as large as the lower ones. Their

size, however, depends on the cakes, which have not the same weight

everywhere; for in some places they are made to weigh six _librae_, in

other places ten, and elsewhere twenty. When the smelter has concluded

his operation, he extinguishes the fire with water, removes the lids

from the pots, throws earth mixed with ash around and over them, and

when they have cooled, takes out the cakes from the pots.

[Illustration 429 (Quicksilver distillation Furnaces): A--Pots.

B--Opercula. C--Nozzles. D--Gourd-shaped earthenware vessels.]

Other methods for reducing quicksilver are given below. Big-bellied

pots, having been placed in the upper rectangular open part of a

furnace, are filled with the crushed ore. Each of these pots is covered

with a lid with a long nozzle--commonly called a _campana_--in the shape

of a bell, and they are cemented. Each of the small earthenware vessels

shaped like a gourd receives two of these nozzles, and these are

likewise cemented. Dried wood having been placed in the lower part of

the furnace and kindled, the ore is heated until all the quicksilver has

risen into the operculum which is over the pot; it then flows from the

nozzle and is caught in the earthenware gourd-shaped vessel.

[Illustration 430 (Quicksilver distillation Furnaces): A--Enclosed

chamber. B--Door. C--Little windows. D--Mouths through the walls.

E--Furnace in the enclosed chamber. F--Pots.]

Others build a hollow vaulted chamber, of which the paved floor is made

concave toward the centre. Inside the thick walls of the chamber are the

furnaces. The doors through which the wood is put are in the outer part

of the same wall. They place the pots in the furnaces and fill them with

crushed ore, then they cement the pots and the furnaces on all sides

with lute, so that none of the vapour may escape from them, and there is

no entrance to the furnaces except through their mouths. Between the

dome and the paved floor they arrange green trees, then they close the

door and the little windows, and cover them on all sides with moss and

lute, so that none of the quicksilver can exhale from the chamber. After

the wood has been kindled the ore is heated, and exudes the

quicksilver; whereupon, impatient with the heat, and liking the cold, it

escapes to the leaves of the trees, which have a cooling power. When the

operation is completed the smelter extinguishes the fire, and when all

gets cool he opens the door and the windows, and collects the

quicksilver, most of which, being heavy, falls of its own accord from

the trees, and flows into the concave part of the floor; if all should

not have fallen from the trees, they are shaken to make it fall.

[Illustration 431 (Quicksilver distillation Furnaces): A--Larger pot.

B--Smaller. C--Tripod. D--Tub in which the sand is washed.]

The following is the fourth method of reducing ores of quicksilver. A

larger pot standing on a tripod is filled with crushed ore, and over the

ore is put sand or ashes to a thickness of two digits, and tamped; then

in the mouth of this pot is inserted the mouth of another smaller pot

and cemented with lute, lest the vapours are emitted. The ore heated by

the fire exhales the quicksilver, which, penetrating through the sand or

the ashes, takes refuge in the upper pot, where condensing into drops it

falls back into the sand or the ashes, from which the quicksilver is

washed and collected.

[Illustration 432 (Quicksilver distillation Furnaces): A--Pots. B--Lids.

C--Stones. D--Furnace.]

The fifth method is not very unlike the fourth. In the place of these

pots are set other pots, likewise of earthenware, having a narrow bottom

and a wide mouth. These are nearly filled with crushed ore, which is

likewise covered with ashes to a depth of two digits and tamped in. The

pots are covered with lids a digit thick, and they are smeared over on

the inside with liquid litharge, and on the lid are placed heavy stones.

The pots are set on the furnace, and the ore is heated and similarly

exhales quicksilver, which fleeing from the heat takes refuge in the

lid; on congealing there, it falls back into the ashes, from which, when

washed, the quicksilver is collected.

By these five methods quicksilver may be made, and of these not one is

to be despised or repudiated; nevertheless, if the mine supplies a great

abundance of ore, the first is the most expeditious and practical,

because a large quantity of ore can be reduced at the same time without

great expense.[58]

[Illustration 434 (Bismuth Smelting): A--Pit across which wood is

placed. B--Forehearth. C--Ladle. D--Iron mould. E--Cakes. F--Empty pot

lined with stones in layers. G--Troughs. H--Pits dug at the foot of the

troughs. I--Small wood laid over the troughs. K--Wind.]

Bismuth[59] ore, free from every kind of silver, is smelted by various

methods. First a small pit is dug in the dry ground; into this

pulverised charcoal is thrown and tamped in, and then it is dried with

burning charcoal. Afterward, thick dry pieces of beech wood are placed

over the pit, and the bismuth ore is thrown on it. As soon as the

kindled wood burns, the heated ore drips with bismuth, which runs down

into the pit, from which when cooled the cakes are removed. Because

pieces of burnt wood, or often charcoal and occasionally slag, drop into

the bismuth which collects in the pit, and make it impure, it is put

back into another kind of crucible to be melted, so that pure cakes may

be made. There are some who, bearing these things in mind, dig a pit on

a sloping place and below it put a forehearth, into which the bismuth

continually flows, and thus remains clean; then they take it out with

ladles and pour it into iron pans lined inside with lute, and make cakes

of it. They cover such pits with flat stones, whose joints are besmeared

with a lute of mixed dust and crushed charcoal, lest the joints should

absorb the molten bismuth. Another method is to put the ore in troughs

made of fir-wood and placed on sloping ground; they place small firewood

over it, kindling it when a gentle wind blows, and thus the ore is

heated. In this manner the bismuth melts and runs down from the troughs

into a pit below, while there remains slag, or stones, which are of a

yellow colour, as is also the wood laid across the pit. These are also

sold.

[Illustration 435 (Bismuth Smelting): A--Wood. B--Bricks. C--Pans.

D--Furnace. E--Crucible. F--Pipe. G--Dipping-pot.]

Others reduce the ore in iron pans as next described. They lay small

pieces of dry wood alternately straight and transversely upon bricks,

one and a half feet apart, and set fire to it. Near it they put small

iron pans lined on the inside with lute, and full of broken ore; then

when the wind blows the flame of the fierce fire over the pans, the

bismuth drips out of the ore; wherefore, in order that it may run, the

ore is stirred with the tongs; but when they decide that all the bismuth

is exuded, they seize the pans with the tongs and remove them, and pour

out the bismuth into empty pans, and by turning many into one they make

cakes. Others reduce the ore, when it is not mixed with _cadmia_,[60] in

a furnace similar to the iron furnace. In this case they make a pit and

a crucible of crushed earth mixed with pulverised charcoal, and into it

they put the broken ore, or the concentrates from washing, from which

they make more bismuth. If they put in ore, they reduce it with charcoal

and small dried wood mixed, and if concentrates, they use charcoal only;

they blow both materials with a gentle blast from a bellows. From the

crucible is a small pipe through which the molten bismuth runs down into

a dipping-pot, and from this cakes are made.

[Illustration 436 (Bismuth Smelting): A--Hearth in which ore is melted.

B--Hearth on which lie drops of bismuth. C--Tongs. D--Basket. E--Wind.]

On a dump thrown up from the mines, other people construct a hearth

exposed to the wind, a foot high, three feet wide, and four and a half

feet long. It is held together by four boards, and the whole is thickly

coated at the top with lute. On this hearth they first put small dried

sticks of fir wood, then over them they throw broken ore; then they lay

more wood over it, and when the wind blows they kindle it. In this

manner the bismuth drips out of the ore, and afterward the ashes of the

wood consumed by the fire and the charcoals are swept away. The drops of

bismuth which fall down into the hearth are congealed by the cold, and

they are taken away with the tongs and thrown into a basket. From the

melted bismuth they make cakes in iron pans.

[Illustration 437 (Bismuth Smelting): A--Box. B--Pivot. C--Transverse

wood beams. D--Grate. E--Its feet. F--Burning wood. G--Stick. H--Pans in

which the bismuth is melted. I--Pans for moulds. K--Cakes. L--Fork.

M--Brush.]

Others again make a box eight feet long, four feet wide, and two feet

high, which they fill almost full of sand and cover with bricks, thus

making the hearth. The box has in the centre a wooden pivot, which turns

in a hole in two beams laid transversely one upon the other; these beams

are hard and thick, are sunk into the ground, both ends are perforated,

and through these holes wedge-shaped pegs are driven, in order that the

beams may remain fixed, and that the box may turn round, and may be

turned toward the wind from whichever quarter of the sky in may blow. In

such a hearth they put an iron grate, as long and wide as the box and

three-quarters of a foot high; it has six feet, and there are so many

transverse bars that they almost touch one another. On the grate they

lay pine-wood and over it broken ore, and over this they again lay

pine-wood. When it has been kindled the ore melts, out of which the

bismuth drips down; since very little wood is burned, this is the most

profitable method of smelting the bismuth. The bismuth drips through the

grate on to the hearth, while the other things remain upon the grate

with the charcoal. When the work is finished, the workman takes a stick

from the hearth and overturns the grate, and the things which have been

accumulated on it; with the brush he sweeps up the bismuth and collects

it in a basket, and then he melts it in an iron pan and makes cakes. As

soon as possible after it is cool, he turns the pans over, so that the

cakes may fall out, using for this purpose a two-pronged fork of which

one prong is again forked. And immediately afterward he returns to his

labours.

END OF BOOK IX.

FOOTNOTES:

[1] The history of the fusion of ores and of metals is the history of

individual processes, and such information as we have been able to

discover upon the individual methods previous to Agricola we give on the

pages where such processes are discussed. In general the records of the

beginnings of metallurgy are so nebular that, if one wishes to shirk the

task, he can adopt the explanation of William Pryce one hundred and

fifty years ago: "It is very probable that the nature and use of Metals

were not revealed to Adam in his state of innocence: the toil and labour

necessary to procure and use those implements of the iron age could not

be known, till they made part of the curse incurred by his fall: 'In the

sweat of thy face shalt thou eat bread, till thou return unto the

ground; in sorrow shalt thou eat of it all the days of thy life'

(Genesis). That they were very early discovered, however, is manifest

from the Mosaick account of Tubal Cain, who was the first instructor of

every artificer in Brass [_sic_] and Iron" (_Mineralogia Cornubiensis_,

p. 2).

It is conceivable that gold could be found in large enough pieces to

have had general use in pre-historic times, without fusion; but copper,

which was also in use, must have been smelted, and therefore we must

assume a considerable development of human knowledge on the subject

prior to any human record. Such incidental mention as exists after

record begins does not, of course, extend to the beginning of any

particular branch of the art--in fact, special arts obviously existed

long before such mention, and down to the complete survey of the state

of the art by Agricola our dates are necessarily "prior to" some first

mention in literature, or "prior to" the known period of existing

remains of metallurgical operations. The scant Egyptian records, the

Scriptures, and the Shoo King give a little insight prior to 1000 B.C.

The more extensive Greek literature of about the 5th to the 3rd

centuries B.C., together with the remains of Greek mines, furnish

another datum point of view, and the Roman and Greek writers at the

beginning of the Christian era give a still larger view. After them our

next step is to the Monk Theophilus and the Alchemists, from the 12th to

the 14th centuries. Finally, the awakening of learning at the end of the

15th and the beginning of the 16th centuries, enables us for the first

time to see practically all that was known. The wealth of literature

which exists subsequent to this latter time makes history thereafter a

matter of some precision, but it is not included in this undertaking.

Considering the great part that the metals have played in civilization,

it is astonishing what a minute amount of information is available on

metallurgy. Either the ancient metallurgists were secretive as to their

art, or the ancient authors despised such common things, or, as is

equally probable, the very partial preservation of ancient literature,

by painful transcription over a score of centuries, served only for

those works of more general interest. In any event, if all the direct or

indirect material on metallurgy prior to the 15th century were compiled,

it would not fill 40 pages such as these.

It may be of service to give a tabular summary indicating approximately

the time when evidence of particular operations appear on the historical

horizon:

Gold washed from alluvial Prior to recorded

civilization

Copper reduced from ores by smelting Prior to recorded

civilization

Bitumen mined and used Prior to recorded

civilization

Tin reduced from ores by smelting Prior to 3500 B.C.

Bronze made Prior to 3500 B.C.

Iron reduced from ores by smelting Prior to 3500 B.C.

Soda mined and used Prior to 3500 B.C.

Gold reduced from ores by concentration Prior to 2500 B.C.

Silver reduced from ores by smelting Prior to 2000 B.C.

Lead reduced from ores by smelting Prior to 2000 B.C.

(perhaps prior

to 3500 B.C.)

Silver parted from lead by cupellation Prior to 2000 B.C.

Bellows used in furnaces Prior to 1500 B.C.

Steel produced Prior to 1000 B.C.

Base metals separated from ores by water Prior to 500 B.C.

concentration

Gold refined by cupellation Prior to 500 B.C.

Sulphide ores smelted for lead Prior to 500 B.C.

Mercury reduced from ores by (?) Prior to 400 B.C.

White-lead made with vinegar Prior to 300 B.C.

Touchstone known for determining gold and silver Prior to 300 B.C.

fineness

Quicksilver reduced from ore by distillation Prior to Christian Era

Silver parted from gold by cementation with salt Prior to " "

Brass made by cementation of copper and calamine Prior to " "

Zinc oxides obtained from furnace fumes by Prior to " "

construction of dust chambers

Antimony reduced from ores by smelting (accidental) Prior to " "

Gold recovered by amalgamation Prior to " "

Refining of copper by repeated fusion Prior to " "

Sulphide ores smelted for copper Prior to " "

Vitriol (blue and green) made Prior to " "

Alum made Prior to " "

Copper refined by oxidation and poling Prior to 1200 A.D.

Gold parted from copper by cupelling with lead Prior to 1200 A.D.

Gold parted from silver by fusion with sulphur Prior to 1200 A.D.

Manufacture of nitric acid and _aqua regia_ Prior to 1400 A.D.

Gold parted from silver by nitric acid Prior to 1400 A.D.

Gold parted from silver with antimony sulphide Prior to 1500 A.D.

Gold parted from copper with sulphur Prior to 1500 A.D.

Silver parted from iron with antimony sulphide Prior to 1500 A.D.

First text book on assaying Prior to 1500 A.D.

Silver recovered from ores by amalgamation Prior to 1500 A.D.

Separation of silver from copper by liquation Prior to 1540 A.D.

Cobalt and manganese used for pigments Prior to 1540 A.D.

Roasting copper ores prior to smelting Prior to 1550 A.D.

Stamp-mill used Prior to 1550 A.D.

Bismuth reduced from ore Prior to 1550 A.D.

Zinc reduced from ore (accidental) Prior to 1550 A.D.

Further, we believe it desirable to sketch at the outset the development

of metallurgical appliances as a whole, leaving the details to special

footnotes; otherwise a comprehensive view of the development of such

devices is difficult to grasp.

We can outline the character of metallurgical appliances at various

periods in a few words. It is possible to set up a description of the

imaginary beginning of the "bronze age" prior to recorded civilization,

starting with the savage who accidentally built a fire on top of some

easily reducible ore, and discovered metal in the ashes, etc.; but as

this method has been pursued times out of number to no particular

purpose, we will confine ourselves to a summary of such facts as we can

assemble. "Founders' hoards" of the bronze age are scattered over

Western Europe, and indicate that smelting was done in shallow pits with

charcoal. With the Egyptians we find occasional inscriptions showing

small furnaces with forced draught, in early cases with a blow-pipe, but

later--about 1500 B.C.--with bellows also. The crucible was apparently

used by the Egyptians in secondary melting, such remains at Mt. Sinai

probably dating before 2000 B.C. With the advent of the Prophets, and

the first Greek literature--9th to 7th century B.C.--we find frequent

references to bellows. The remains of smelting appliances at Mt. Laurion

(500-300 B.C.) do not indicate much advance over the primitive hearth;

however, at this locality we do find evidence of the ability to separate

minerals by specific gravity, by washing crushed ore over inclined

surfaces with a sort of buddle attachment. Stone grinding-mills were

used to crush ore from the earliest times of Mt. Laurion down to the

Middle Ages. About the beginning of the Christian era the writings of

Diodorus, Strabo, Dioscorides, and Pliny indicate considerable advance

in appliances. Strabo describes high stacks to carry off lead fumes;

Dioscorides explains a furnace with a dust-chamber to catch _pompholyx_

(zinc oxide); Pliny refers to the upper and lower crucibles (a

forehearth) and to the pillars and arches of the furnaces. From all of

their descriptions we may conclude that the furnaces had then reached

some size, and were, of course, equipped with bellows. At this time

sulphide copper and lead ores were smelted; but as to fluxes, except

lead for silver, and lead and soda for gold, we have practically no

mention. Charcoal was the universal fuel for smelting down to the 18th

century. Both Dioscorides and Pliny describe a distillation apparatus

used to recover quicksilver. A formidable list of mineral products and

metal alloys in use, indicate in themselves considerable apparatus, of

the details of which we have no indication; in the main these products

were lead sulphide, sulphate, and oxide (red-lead and litharge); zinc

oxide; iron sulphide, oxide and sulphate; arsenic and antimony

sulphides; mercury sulphide, sulphur, bitumen, soda, alum and potash;

and of the alloys, bronze, brass, pewter, electrum and steel.

From this period to the period of the awakening of learning our only

light is an occasional gleam from Theophilus and the Alchemists. The

former gave a more detailed description of metallurgical appliances than

had been done before, but there is little vital change apparent from the

apparatus of Roman times. The Alchemists gave a great stimulus to

industrial chemistry in the discovery of the mineral acids, and

described distillation apparatus of approximately modern form.

The next period--the Renaissance--is one in which our descriptions are

for the first time satisfactory, and a discussion would be but a review

of _De Re Metallica_.

[2] See footnote 2, p. 267, on verbs used for roasting.

[3] Agricola has here either forgotten to take into account his

three-palm-thick furnace walls, which will make the length of this long

wall sixty-one feet, or else he has included this foot and a half in

each case in the six-foot distance between the furnaces, so that the

actual clear space is only four and a half feet between the furnace with

four feet on the ends.

[4] The paucity of terms in Latin for describing structural members, and

the consequent repetition of "beam" (_trabs_), "timber" (_tignum_),

"billet" (_tigillum_), "pole" (_asser_), with such modifications as

small, large, and transverse, and with long explanatory clauses showing

their location, renders the original very difficult to follow. We have,

therefore, introduced such terms as "posts," "tie-beams," "sweeps,"

"levers," "rafters," "sills," "moulding," "braces," "cleats,"

"supports," etc., as the context demands.

[5] This set of rafters appears to start from the longitudinal beam.

[6] Devices for creating an air current must be of very old invention,

for it is impossible to conceive of anything but the crudest melting of

a few simple ores without some forced draft. Wilkinson (The Ancient

Egyptians, II, p. 316) gives a copy of an illustration of a foot-bellows

from a tomb of the time of Thotmes III. (1500 B.C.). The rest of the

world therefore, probably obtained them from the Egyptians. They are

mentioned frequently in the Bible, the most pointed reference to

metallurgical purposes being Jeremiah (VI, 29): "The bellows are burned,

the lead is consumed in the fire; the founder melteth in vain; for the

wicked are not plucked away." Strabo (VII, 3) states that Ephorus

ascribed the invention of bellows to Anacharsis--a Thracian prince of

about 600 B.C.

[7] This whole arrangement could be summarized by the word "hinge."

[8] The rim of this wheel is obviously made of segments fixed in two

layers; the "disc" meaning the aggregate of segments on either side of

the wheel.

[9] It has not been considered necessary to introduce the modern term

_twyer_ in these descriptions, as the literal rendering is sufficiently

clear.

[10] _Ferruminata_. These accretions are practically always near the

hearth, and would correspond to English "sows," and therefore that term

has been adopted. It will be noted that, like most modern metallurgists,

Agricola offers no method for treating them. Pliny (XXXIV, 37) describes

a "sow," and uses the verb _ferruminare_ (to weld or solder): "Some say

that in the furnace there are certain masses of stone which become

soldered together, and that the copper fuses around it, the mass not

becoming liquid unless it is transferred to another furnace; it thus

forms a sort of knot, as it were, of the metal."

[11] What are known in English as "crucible," "furnace well,"

"forehearth," "dipping-pot," "tapping-pot," "receiving-pot," etc., are

in the text all _catinus_, _i.e._, crucible. For easier reading,

however, we have assigned the names indicated in the context.

[12] _Panes ex pyrite conflati_. While the term _matte_ would cover most

cases where this expression appears, and in many cases would be more

expressive to the modern reader, yet there are instances where the

expression as it stands indicates its particular origin, and it has

been, therefore, considered advisable to adhere to the literal

rendering.

[13] _Molybdaena_. See note 37, p. 476. It was the saturated furnace

bottoms from cupellation.

[14] The four elements were earth, air, fire, and water.

[15] "Stones which easily melt in the fire." Nowhere in _De Re

Metallica_ does the author explain these substances. However in the

_Interpretatio_ (p. 465) he gives three genera or orders with their

German equivalents, as follows:--"_Lapides qui igni liquescunt primi

generis,--Schoene fluesse; secundi,--fluesse zum schmeltzen flock quertze;

tertii,--quertze oder kiselstein."_ We confess our inability to make

certain of most of the substances comprised in the first and second

orders. We consider they were in part fluor-spar, and in any event the

third order embraced varieties of quartz, flint, and silicious material

generally. As the matter is of importance from a metallurgical point of

view, we reproduce at some length Agricola's own statements on the

subject from _Bermannus_ and _De Natura Fossilium_. In the latter (p.

268) he states: "Finally there now remain those stones which I call

'stones which easily melt in the fire,' because when thrown into hot

furnaces they flow (_fluunt_). There are three orders (_genera_) of

these. The first resembles the transparent gems; the second is not

similar, and is generally not translucent; it is translucent in some

part, and in rare instances altogether translucent. The first is

sparingly found in silver and other mines; the second abounds in veins

of its own. The third genus is the material from which glass is made,

although it can also be made out of the other two. The stones of the

first order are not only transparent, but are also resplendent, and have

the colours of gems, for some resemble crystal, others emerald,

heliotrope, lapis lazuli, amethyst, sapphire, ruby, _chrysolithus_,

_morion_ (cairngorm?), and other gems, but they differ from them in

hardness.... To the first genus belongs the _lapis alabandicus_ (modern

albandite?), if indeed it was different from the alabandic carbuncle. It

can be melted, according to Pliny, in the fire, and fused for the

preparation of glass. It is black, but verging upon purple. It comes

from Caria, near Alabanda, and from Miletus in the same province. The

second order of stones does not show a great variety of colours, and

seldom beautiful ones, for it is generally white, whitish, greyish, or

yellowish. Because these (stones) very readily melt in the fire, they

are added to the ores from which the metals are smelted. The small

stones found in veins, veinlets, and the spaces between the veins, of

the highest peaks of the Sudetic range (_Suditorum montium_), belong

partly to this genus and partly to the first. They differ in size, being

large and small; and in shape, some being round or angular or pointed;

in colour they are black or ash-grey, or yellow, or purple, or violet,

or iron colour. All of these are lacking in metals. Neither do the

little stones contain any metals which are usually found in the streams

where gold dust is collected by washing.... In the rivers where are

collected the small stones from which tin is smelted, there are three

genera of small stones to be found, all somewhat rounded and of very

light weight, and devoid of all metals. The largest are black, both on

the outside and inside, smooth and brilliant like a mirror; the

medium-sized are either bluish black or ash-grey; the smallest are of a

yellowish colour, somewhat like a silkworm. But because both the former

and the latter stones are devoid of metals, and fly to pieces under the

blows of the hammer, we classify them as sand or gravel. Glass is made

from the stones of the third order, and particularly from sand. For when

this is thrown into the heated furnace it is melted by the fire.... This

kind of stone is either found in its own veins, which are occasionally

very wide, or else scattered through the mines. It is less hard than

flint, on account of which no fire can be struck from it. It is not

transparent, but it is of many colours--that is to say, white,

yellowish, ash-grey, brown, black, green, blue, reddish or red. This

genus of stones occurs here and there in mountainous regions, on banks

of rivers, and in the fields. Those which are black right through to the

interior, and not merely on the surface, are more rare; and very

frequently one coloured vein is intersected by another of a different

colour--for instance, a white one by a red one; the green is often

spotted with white, the ash-grey with black, the white with crimson.

Fragments of these stones are frequently found on the surface of the

earth, and in the running water they become polished by rubbing against

stones of their own or of another genus. In this way, likewise,

fragments of rocks are not infrequently shaped into spherical forms....

This stone is put to many uses; the streets are paved with it, whatever

its colour; the blue variety is added to the ash of pines for making

those other ashes which are used by wool-dyers. The white variety is

burned, ground, and sifted, and from this they make the sand out of

which glass is made. The whiter the sand is, the more useful it is."

Perusal of the following from _Bermannus_ (p. 458) can leave little

doubt as to the first or second order being in part fluor-spar. Agricola

derived the name _fluores_ from _fluo_ "to flow," and we in turn obtain

"fluorite," or "fluorspar," from Agricola. "_Bermannus_.--These stones

are similar to gems, but less hard. Allow me to explain word for word.

Our miners call them _fluores_, not inappropriately to my mind, for by

the heat of fire, like ice in the sun, they liquefy and flow away. They

are of varied and bright colours. _Naevius_.--Theophrastus says of them

that they are made by a conflux in the earth. These red _fluores_, to

employ the words just used by you, are the ruby silver which you showed

us before. _Bermannus_.--At the first glance it appears so, although it

is not infrequently translucent. _Naevius_.--Then they are rubies?

_Bermannus_.--Not that either. _Naevius_.--In what way, then, can they

be distinguished from rubies? _Bermannus_.--Chiefly by this sign, that

they glitter more feebly when translucent. Those which are not

translucent may be distinguished from rubies. Moreover, _fluores_ of all

kinds melt when they are subject to the first fire; rubies do not melt

in fire. _Naevius_.--You distinguish well. _Bermannus_.--You see the

other kind, of a paler purple colour? _Naevius_.--They appear to be an

inferior kind of amethyst, such as are found in many places in Bohemia.

_Bermannus_.--Indeed, they are not very dissimilar, therefore the common

people who do not know amethysts well, set them in rings for gems, and

they are easily sold. The third kind, as you see here, is white.

_Naevius_.--I should have thought it a crystal. _Bermannus_.--A fourth

is a yellow colour, a fifth ash colour, a sixth blackish. Some are

violet, some green, others gold-coloured. _Anton_.--What is the use of

_fluores_? _Bermannus_.--They are wont to be made use of when metals are

smelted, as they cause the material in the fire to be much more fluid,

exactly like a kind of stone which we said is made from pyrites (matte);

it is, indeed, made not far from here, at Breitenbrunn, which is near

Schwarzenberg. Moreover, from _fluores_ they can make colours which

artists use."

[16] _Stannum_. (_Interpretatio_,--_werck_, modern _werk_). This term

has been rendered throughout as "silver-lead" or "silver-lead alloy." It

was the argentiferous lead suitable for cupellation. Agricola, in using

it in this sense, was no doubt following his interpretation of its use

by Pliny. Further remarks upon this subject will be found in note 33, p.

473.

[17] _Expirare_,--to exhale or blow out.

[18] _Rhetos_. The ancient Rhaetia comprised not only the greater part

of Tyrol, but also parts of Switzerland and Lombardy. The mining section

was, however, in Tyrol.

[19] _Noricum_ was a region south of the Danube, embracing not only

modern Styria, but also parts of Austria, Salzberg, and Carinthia.

[20] One _drachma_ of gold to a _centumpondium_ would be (if we assume

these were Roman weights) 3 ozs. 1 dwt. Troy per short ton. One-half

_uncia_ of silver would be 12 ozs. 3 dwts. per short ton.

[21] For discussion of these fluxes see note page 232.

[22] _Carni_. Probably the people of modern Austrian Carniola, which

lies south of Styria and west of Croatia.

[23] HISTORICAL NOTE ON SMELTING LEAD AND SILVER.--The history of lead

and silver smelting is by no means a sequent array of exact facts. With

one possible exception, lead does not appear upon the historical horizon

until long after silver, and yet their metallurgy is so inextricably

mixed that neither can be considered wholly by itself. As silver does

not occur native in any such quantities as would have supplied the

amounts possessed by the Ancients, we must, therefore, assume its

reduction by either (1) intricate chemical processes, (2) amalgamation,

(3) reduction with copper, (4) reduction with lead. It is impossible to

conceive of the first with the ancient knowledge of chemistry; the

second (see note 12, p. 297) does not appear to have been known until

after Roman times; in any event, quicksilver appears only at about 400

B.C. The third was impossible, as the parting of silver from copper

without lead involves metallurgy only possible during the last century.

Therefore, one is driven to the conclusion that the fourth case

obtained, and that the lead must have been known practically

contemporaneously with silver. There is a leaden figure exhibited in the

British Museum among the articles recovered from the Temple of Osiris at

Abydos, and considered to be of the Archaic period--prior to 3800 B.C.

The earliest known Egyptian silver appears to be a necklace of beads,

supposed to be of the XII. Dynasty (2400 B.C.), which is described in

the 17th Memoir, Egyptian Exploration Fund (London, 1898, p. 22). With

this exception of the above-mentioned lead specimen, silver articles

antedate positive evidence of lead by nearly a millennium, and if we

assume lead as a necessary factor in silver production, we must conclude

it was known long prior to any direct (except the above solitary

possibility) evidence of lead itself. Further, if we are to conclude its

necessary association with silver, we must assume a knowledge of

cupellation for the parting of the two metals. Lead is mentioned in 1500

B.C. among the spoil captured by Thotmes III. Leaden objects have

frequently been found in Egyptian tombs as early as Rameses III. (1200

B.C.). The statement is made by Pulsifer (Notes for a History of Lead,

New York 1888, p. 146) that Egyptian pottery was glazed with lead. We

have been unable to find any confirmation of this. It may be noted,

incidentally, that lead is not included in the metals of the "Tribute of

Yue" in the Shoo King (The Chinese Classics, 2500 B.C.?), although silver

is so included.

After 1200 or 1300 B.C. evidences of the use of lead become frequent.

Moses (Numbers XXXI, 22-23) directs the Israelites with regard to their

plunder from the Midianites (1300 B.C.): "Only the gold and the silver,

the brass [_sic_], the iron, the tin, and the lead. Everything that may

abide the fire, ye shall make it go through the fire, and it shall be

clean; nevertheless, it shall be purified with the water of separation,

and all that abideth not the fire ye shall make go through the water."

Numerous other references occur in the Scriptures (Psalms XII, 6;

Proverbs XVII, 3; XXV, 4; etc.), one of the most pointed from a

metallurgical point of view being that of Jeremiah (600 B.C.), who says

(VI, 29-30): "The bellows are burned, the lead is consumed of the fire;

the founder melteth in vain; for the wicked are not plucked away.

Reprobate silver shall men call them because the Lord hath rejected

them." From the number of his metaphors in metallurgical terms we may

well conclude that Jeremiah was of considerable metallurgical

experience, which may account for his critical tenor of mind. These

Biblical references all point to a knowledge of separating silver and

lead. Homer mentions lead (Iliad XXIV, 109), and it has been found in

the remains of ancient Troy and Mycenae (H. Schliemann, "Troy and its

Remains," London, 1875, and "Mycenae," New York, 1877). Both Herodotus

(I, 186) and Diodorus (II, 1) speak of the lead used to fix iron clamps

in the stone bridge of Nitocris (600 B.C.) at Babylon.

Our best evidence of ancient lead-silver metallurgy is the result of the

studies at Mt. Laurion by Edouard Ardaillon (_Mines du Laurion dans

l'Antiquite_, Paris, 1897). Here the very extensive old workings and the

slag heaps testify to the greatest activity. The re-opening of the mines

in recent years by a French Company has well demonstrated their

technical character, and the frequent mention in Greek History easily

determines their date. These deposits of argentiferous galena were

extensively worked before 500 B.C. and while the evidence of

concentration methods is ample, there is but little remaining of the

ancient smelters. Enough, however, remains to demonstrate that the

galena was smelted in small furnaces at low heat, with forced draught,

and that it was subsequently cupelled. In order to reduce the sulphides

the ancient smelters apparently depended upon partial roasting in the

furnace at a preliminary period in reduction, or else upon the

ferruginous character of the ore, or upon both. See notes p. 27 and p.

265. Theognis (6th century B.C.) and Hippocrates (5th century B.C.) are

frequently referred to as mentioning the refining of gold with lead; an

inspection of the passages fails to corroborate the importance which has

been laid upon them. Among literary evidences upon lead metallurgy of

later date, Theophrastus (300 B.C.) describes the making of white-lead

with lead plates and vinegar. Diodorus Siculus (1st century B.C.), in

his well-known quotation from Agatharchides (2nd century B.C.) with

regard to gold mining and treatment in Egypt, describes the refining of

gold with lead. (See note 8, p. 279.) Strabo (63 B.C.-24 A.D.) says

(III, 2, 8): "The furnaces for silver are constructed lofty in order

that the vapour, which is dense and pestilent, may be raised and carried

off." And again (III, 2, 10), in quoting from Polybius (204-125 B.C.):

"Polybius, speaking of the silver mines of New Carthage, tells us that

they are extremely large, distant from the city about 20 stadia, and

occupy a circuit of 400 stadia; that there are 40,000 men regularly

engaged in them, and that they yield daily to the Roman people (a

revenue of) 25,000 drachmae. The rest of the process I pass over, as it

is too long; but as for the silver ore collected, he tells us that it is

broken up and sifted through sieves over water; that what remains is to

be again broken, and the water having been strained off it is to be

sifted and broken a third time. The dregs which remain after the fifth

time are to be melted, and the lead being poured off, the silver is

obtained pure. These silver mines still exist; however, they are no

longer the property of the State, neither these nor those elsewhere, but

are possessed by private individuals. The gold mines, on the contrary,

nearly all belong to the State. Both at Castlon and other places there

are singular lead mines worked. They contain a small proportion of

silver, but not sufficient to pay for the expense of refining"

(Hamilton's Trans.). Dioscorides (1st century A.D.), among his

medicines, describes several varieties of litharge, their origin, and

the manner of making white-lead (see on pp. 465, 440), but he gives no

very tangible information on lead smelting. Pliny, at the same period in

speaking of silver, (XXXIII, 31), says: "After this we speak of silver,

the next folly. Silver is only found in shafts, there being no

indications like shining particles as in the case of gold. This earth is

sometimes red, sometimes of an ashy colour. It is impossible to melt it

except with lead ore (_vena plumbi_), called _galena_, which is

generally found next to silver veins. And this the same agency of fire

separates part into lead, which floats on the silver like oil on water."

(We have transferred lead and silver in this last sentence, otherwise it

means nothing.) Also (XXXIV, 47) he says: "There are two different

sources of lead, it being smelted from its own ore, whence it comes

without the admixture of any other substance, or else from an ore which

contains it in common with silver. The metal, which flows liquid at the

first melting in the furnace, is called _stannum_ that at the second

melting is silver; that which remains in the furnace is _galena_, which

is added to a third part of the ore. This being again melted, produces

lead with a deduction of two-ninths." We have, despite some grammatical

objections, rendered this passage quite differently from other

translators, none of whom have apparently had any knowledge of

metallurgy; and we will not, therefore, take the several pages of space

necessary to refute their extraordinary and unnecessary hypotheses. From

a metallurgical point of view, two facts must be kept in mind,--first,

that _galena_ in this instance was the same substance as _molybdaena_,

and they were both either a variety of litharge or of lead carbonates;

second, that the _stannum_ of the Ancients was silver-lead alloy.

Therefore, the metallurgy of this paragraph becomes a simple melting of

an argentiferous lead ore, its subsequent cupellation, with a return of

the litharge to the furnace. Pliny goes into considerable detail as to

varieties of litharge, for further notes upon which see p. 466. The

Romans were most active lead-silver miners, not only in Spain, but also

in Britain. There are scores of lead pigs of the Roman era in various

English museums, many marked "_ex argent_." Bruce (The Roman Wall,

London, 1852, p. 432) describes some Roman lead furnaces in Cumberland

where the draught was secured by driving a tapering tunnel into the

hills. The Roman lead slag ran high in metal, and formed a basis for

quite an industry in England in the early 18th century (Hunt, British

Mining, London, 1887, p. 26, etc.). There is nothing in mediaeval

literature which carries us further with lead metallurgy than the

knowledge displayed by Pliny, until we arrive at Agricola's period. The

history of cupellation is specially dealt with in note on p. 465.

[25] _Cadmia_. In the German Translation this is given as _kobelt_. It

would be of uncertain character, but no doubt partially furnace

calamine. (See note on p. 112.)

[26] _Pompholyx_. (_Interpretatio_ gives the German as _Weisser huetten

rauch als ober dem garherde und ober dem kupfer ofen_). This was the

impure protoxide of zinc deposited in the furnace outlets, and is modern

"tutty." The ancient products, no doubt, contained arsenical oxides as

well. It was well known to the Ancients, and used extensively for

medicinal purposes, they dividing it into two species--_pompholyx_ and

_spodos_. The first adequate description is by Dioscorides (V, 46):

"_Pompholyx_ differs from _spodos_ in species, not in genus. For

_spodos_ is blacker, and is often heavier, full of straws and hairs,

like the refuse that is swept from the floors of copper smelters. But

_pompholyx_ is fatty, unctuous, white and light enough to fly in the

air. Of this there are two kinds--the one inclines to sky blue and is

unctuous; the other is exceedingly white, and is extremely light. White

_pompholyx_ is made every time that the artificer, in the preparation

and perfecting of copper (brass?) sprinkles powdered _cadmia_ upon it to

make it more perfect, for the soot which rises being very fine becomes

_pompholyx_. Other _pompholyx_ is made, not only in working copper

(brass?), but is also made from _cadmia_ by continually blowing with

bellows. The manner of doing it is as follows:--The furnace is

constructed in a two-storied building, and there is a medium-sized

aperture opening to the upper chamber; the building wall nearest the

furnace is pierced with a small opening to admit the nozzle of the

bellows. The building must have a fair-sized door for the artificer to

pass in and out. Another small building must adjoin this, in which are

the bellows and the man who works them. Then the charcoal in the furnace

is lighted, and the artificer continually throws broken bits of _cadmia_

from the place above the furnace, whilst his assistant, who is below,

throws in charcoals, until all of the _cadmia_ inside is consumed. By

this means the finest and lightest part of the stuff flies up with the

smoke to the upper chamber, and adheres to the walls of the roof. The

substance which is thus formed has at first the appearance of bubbles on

water, afterward increasing in size, it looks like skeins of wool. The

heaviest parts settle in the bottom, while some fall over and around the

furnaces, and some lie on the floor of the building. This latter part is

considered inferior, as it contains a lot of earth and becomes full of

dirt."

Pliny (XXXIV, 33) appears somewhat confused as to the difference between

the two species: "That which is called _pompholyx_ and _spodos_ is found

in the copper-smelting furnaces, the difference between them being that

_pompholyx_ is separated by washing, while _spodos_ is not washed. Some

have called that which is white and very light _pompholyx_, and it is

the soot of copper and _cadmia_; whereas _spodos_ is darker and heavier.

It is scraped from the walls of the furnace, and is mixed with particles

of metal, and sometimes with charcoal." (XXXIV, 34.) "The Cyprian

_spodos_ is the best. It is formed by fusing _cadmia_ with copper ore.

This being the lightest part of the metal, it flies up in the fumes from

the furnace, and adheres to the roof, being distinguished from the soot

by its whiteness. That which is less white is immature from the furnace,

and it is this which some call '_pompholyx_.'" Agricola (_De Natura

Fossilium_, p. 350) traverses much the same ground as the authors

previously quoted, and especially recommends the _pompholyx_ produced

when making brass by melting alternate layers of copper and calamine

(_cadmia fossilis_).

[27] _Oleo, ex fece vini sicca confecto_. This oil, made from argol, is

probably the same substance mentioned a few lines further on as "wine,"

distilled by heating argol in a retort. Still further on, salt made from

argol is mentioned. It must be borne in mind that this argol was crude

tartrates from wine vats, and probably contained a good deal of organic

matter. Heating argol sufficiently would form potash, but that the

distillation product could be anything effective it is difficult to see.

[28] _Aqua valens_. No doubt mainly nitric acid, the preparation of

which is explained at length in Book X, p. 439.

[29] _Quod cum ignis consumit non modo una cum eo, quae ipsius stibii

vis est, aliqua auri particula, sed etiam argenti, si cum auro fuerit

permistum, consumitur._ The meaning is by no means clear. On p. 451 is

set out the old method of parting silver from gold with antimony

sulphide, of which this may be a variation. The silver combines with

sulphur, and the reduced antimony forms an alloy with the gold. The

added iron and copper would also combine with the sulphur from the

antimony sulphide, and no doubt assist by increasing the amount of free

collecting agent and by increasing the volume of the matte. (See note

17, p. 451.)

[30] There follow eight different methods of treating crude bullion or

rich concentrates. In a general way three methods are involved,--1st,

reduction with lead or antimony, and cupellation; 2nd, reduction with

silver, and separation with nitric acid; 3rd, reduction with lead and

silver, followed by cupellation and parting with nitric acid. The use of

sulphur or antimony sulphide would tend to part out a certain amount of

silver, and thus obtain fairly pure bullion upon cupellation. But the

introduction of copper could only result deleteriously, except that it

is usually accompanied by sulphur in some form, and would thus probably

pass off harmlessly as a matte carrying silver. (See note 33 below.)

[31] It is not very clear where this lead comes from. Should it be

antimony? The German translation gives this as "silver."

[32] These powders are described in Book VII., p. 236. It is difficult

to say which the second really is. There are numbers of such recipes in

the _Probierbuechlein_ (see Appendix B), with which a portion of these

are identical.

[33] A variety of methods are involved in this paragraph: 1st, crude

gold ore is smelted direct; 2nd, gold concentrates are smelted in a lead

bath with some addition of iron--which would simply matte off--the lead

bullion being cupelled; 3rd, roasted and unroasted pyrites and _cadmia_

(probably blende, cobalt, arsenic, etc.) are melted into a matte; this

matte is repeatedly roasted, and then re-melted in a lead bath; 4th, if

the material "flies out of the furnace" it is briquetted with iron ore

and lime, and the briquettes smelted with copper matte. Three products

result: (_a_) slag; (_b_) matte; (_c_) copper-gold-silver alloy. The

matte is roasted, re-smelted with lead, and no doubt a button obtained,

and further matte. The process from this point is not clear. It appears

that the copper bullion is melted with lead, and normally this product

would be taken to the liquation furnace, but from the text it would

appear that the lead-copper bullion was melted again with iron ore and

pyrites, in which case some of the copper would be turned into the

matte, and the lead alloy would be richer in gold and silver.

HISTORICAL NOTE ON GOLD.--There is ample evidence of gold being used for

ornamental purposes prior to any human record. The occurrence of large

quantities of gold in native form, and the possibility of working it

cold, did not necessitate any particular metallurgical ingenuity. The

earliest indications of metallurgical work are, of course, among the

Egyptians, the method of washing being figured as early as the monuments

of the IV Dynasty (prior to 3800 B.C.). There are in the British Museum

two stelae of the XII Dynasty (2400 B.C.) (144 Bay 1 and 145 Bay 6)

relating to officers who had to do with gold mining in Nubia, and upon

one there are references to working what appears to be ore. If this be

true, it is the earliest reference to this subject. The Papyrus map

(1500 B.C.) of a gold mine, in the Turin Museum (see note 16, p. 129),

probably refers to a quartz mine. Of literary evidences there is

frequent mention of refining gold and passing it through the fire in the

Books of Moses, arts no doubt learned from the Egyptians. As to working

gold, ore as distinguished from alluvial, we have nothing very tangible,

unless it be the stelae above, until the description of Egyptian gold

mining by Agatharchides (see note 8, p. 279). This geographer, of about

the 2nd century B.C., describes very clearly indeed the mining,

crushing, and concentration of ore and the refining of the concentrates

in crucibles with lead, salt, and barley bran. We may mention in passing

that Theognis (6th Century B.C.) is often quoted as mentioning the

refining of gold with lead, but we do not believe that the passage in

question (1101): "But having been put to the test and being rubbed

beside (or against) lead as being refined gold, you will be fair," etc.;

or much the same statement again (418) will stand much metallurgical

interpretation. In any event, the myriads of metaphorical references to

fining and purity of gold in the earliest shreds of literature do not

carry us much further than do those of Shakespeare or Milton. Vitruvius

and Pliny mention the recovery or refining of gold with mercury (see

note 12, p. 297 on Amalgamation); and it appears to us that gold was

parted from silver by cementation with salt prior to the Christian era.

We first find mention of parting with sulphur in the 12th century, with

nitric acid prior to the 14th century, by antimony sulphide prior to the

15th century, and by cementation with nitre by Agricola. (See historical

note on parting gold and silver, p. 458.) The first mention of parting

gold from copper occurs in the early 16th century (see note 24, p. 462).

The first comprehensive description of gold metallurgy in all its

branches is in _De Re Metallica_.

[34] _Rudis_ silver comprised all fairly pure silver ores, such as

silver sulphides, chlorides, arsenides, etc. This is more fully

discussed in note 6, p. 108.

[35] _Evolent_,--volatilize?

[36] _Lapidis plumbarii facile liquescentis_. The German Translation

gives _glantz_, _i.e._, Galena, and the _Interpretatio_ also gives

_glantz_ for _lapis plumbarius_. We are, however, uncertain whether this

"easily melting" material is galena or some other lead ore.

[37] _Molybdaena_ is usually hearth-lead in _De Re Metallica_, but the

German translation in this instance uses _pleyertz_, lead ore. From the

context it would not appear to mean hearth-lead--saturated bottoms of

cupellation furnaces--for such material would not contain appreciable

silver. Agricola does confuse what are obviously lead carbonates with

his other _molybdaena_ (see note 37, p. 476).

[38] The term _cadmia_ is used in this paragraph without the usual

definition. Whether it was _cadmia fornacis_ (furnace accretions) or

_cadmia metallica_ (cobalt-arsenic-blende mixture) is uncertain. We

believe it to be the former.

[39] _Ramentum si lotura ex argento rudi_. This expression is generally

used by the author to indicate concentrates, but it is possible that in

this sentence it means the tailings after washing rich silver minerals,

because the treatment of the _rudis_ silver has been already discussed

above.

[40] _Ustum_. This might be rendered "burnt." In any event, it seems

that the material is sintered.

[41] _Aes purum sive proprius ei color insederit, sive chrysocolla vel

caeruleo fuerit tinctum, et rude plumbei coloris, aut fusci, aut nigri._

There are six copper minerals mentioned in this sentence, and from our

study of Agricola's _De Natura Fossilium_ we hazard the

following:--_Proprius ei color insederit_,--"its own colour,"--probably

cuprite or "ruby copper." _Tinctum chrysocolla_--partly the modern

mineral of that name and partly malachite. _Tinctum caeruleo_, partly

azurite and partly other blue copper minerals. _Rude plumbei

coloris_,--"lead coloured,"--was certainly chalcocite (copper glance).

We are uncertain of _fusci aut nigri_, but they were probably alteration

products. For further discussion see note on p. 109.

[42] HISTORICAL NOTE ON COPPER SMELTING.--The discoverer of the

reduction of copper by fusion, and his method, like the discoverer of

tin and iron, will never be known, because he lived long before humanity

began to make records of its discoveries and doings. Moreover, as

different races passed independently and at different times through the

so-called "Bronze Age," there may have been several independent

discoverers. Upon the metallurgy of pre-historic man we have some

evidence in the many "founders' hoards" or "smelters' hoards" of the

Bronze Age which have been found, and they indicate a simple shallow pit

in the ground into which the ore was placed, underlaid with charcoal.

Rude round copper cakes eight to ten inches in diameter resulted from

the cooling of the metal in the bottom of the pit. Analyses of such

Bronze Age copper by Professor Gowland and others show a small

percentage of sulphur, and this is possible only by smelting oxidized

ores. Copper objects appear in the pre-historic remains in Egypt, are

common throughout the first three dynasties, and bronze articles have

been found as early as the IV Dynasty (from 3800 to 4700 B.C., according

to the authority adopted). The question of the origin of this bronze,

whether from ores containing copper and tin or by alloying the two

metals, is one of wide difference of opinion, and we further discuss the

question in note 53, p. 411, under Tin. It is also interesting to note

that the crucible is the emblem of copper in the hieroglyphics. The

earliest source of Egyptian copper was probably the Sinai Peninsula,

where there are reliefs as early as Seneferu (about 3700 B.C.),

indicating that he worked the copper mines. Various other evidences

exist of active copper mining prior to 2500 B.C. (Petrie, Researches in

Sinai, London, 1906, p. 51, etc.). The finding of crucibles here would

indicate some form of refining. Our knowledge of Egyptian copper

metallurgy is limited to deductions from their products, to a few

pictures of crude furnaces and bellows, and to the minor remains on the

Sinai Peninsula; none of the pictures were, so far as we are aware,

prior to 2300 B.C., but they indicate a considerable advance over the

crude hearth, for they depict small furnaces with forced draught--first

a blow-pipe, and in the XVIII Dynasty (about 1500 B.C.) the bellows

appear. Many copper articles have been found scattered over the Eastern

Mediterranean and Asia Minor of pre-Mycenaean Age, some probably as

early as 3000 B.C. This metal is mentioned in the "Tribute of Yue" in the

Shoo King (2500 B.C.?); but even less is known of early Chinese

metallurgy than of the Egyptian. The remains of Mycenaean, Phoenician,

Babylonian, and Assyrian civilizations, stretching over the period from

1800 to 500 B.C., have yielded endless copper and bronze objects, the

former of considerable purity, and the latter a fairly constant

proportion of from 10% to 14% tin. The copper supply of the pre-Roman

world seems to have come largely, first from Sinai, and later from

Cyprus, and from the latter comes our word copper, by way of the Romans

shortening _aes cyprium_ (Cyprian copper) to _cuprum_. Research in this

island shows that it produced copper from 3000 B.C., and largely because

of its copper it passed successively under the domination of the

Egyptians, Assyrians, Phoenicians, Greeks, Persians, and Romans. The

bronze objects found in Cyprus show 2% to 10% of tin, although tin does

not, so far as modern research goes, occur on that island. There can be

no doubt that the Greeks obtained their metallurgy from the Egyptians,

either direct or second-hand--possibly through Mycenae or Phoenicia.

Their metallurgical gods and the tradition of Cadmus indicate this much.

By way of literary evidences, the following lines from Homer (Iliad,

XVIII.) have interest as being the first preserved description in any

language of a metallurgical work. Hephaestus was much interrupted by

Thetis, who came to secure a shield for Achilles, and whose general

conversation we therefore largely omit. We adopt Pope's translation:--

There the lame architect the goddess found

Obscure in smoke, his forges flaming round,

While bathed in sweat from fire to fire he flew;

And puffing loud the roaring bellows blew.

* * *

In moulds prepared, the glowing ore (metal?) he pours.

* * *

"Vouchsafe, oh Thetis! at our board to share

The genial rites and hospitable fare;

While I the labours of the forge forego,

And bid the roaring bellows cease to blow."

Then from his anvil the lame artist rose;

Wide with distorted legs oblique he goes,

And stills the bellows, and (in order laid)

Locks in their chests his instruments of trade;

Then with a sponge, the sooty workman dress'd

His brawny arms embrown'd and hairy breast.

* * *

Thus having said, the father of the fires

To the black labours of his forge retires.

Soon as he bade them blow the bellows turn'd

Their iron mouths; and where the furnace burn'd

Resounding breathed: at once the blast expires,

And twenty forges catch at once the fires;

Just as the God directs, now loud, now low,

They raise a tempest, or they gently blow;

In hissing flames huge silver bars are roll'd,

And stubborn brass (copper?) and tin, and solid gold;

Before, deep fixed, the eternal anvils stand.

The ponderous hammer loads his better hand;

His left with tongs turns the vex'd metal round.

And thick, strong strokes, the doubling vaults rebound

Then first he formed the immense and solid shield;

Even if we place the siege of Troy at any of the various dates from 1350

to 1100 B.C., it does not follow that the epic received its final form

for many centuries later, probably 900-800 B.C.; and the experience of

the race in metallurgy at a much later period than Troy may have been

drawn upon to fill in details. It is possible to fill a volume with

indirect allusion to metallurgical facts and to the origins of the art,

from Greek mythology, from Greek poetry, from the works of the

grammarians, and from the Bible. But they are of no more technical value

than the metaphors from our own tongue. Greek literature in general is

singularly lacking in metallurgical description of technical value, and

it is not until Dioscorides (1st Century A.D.) that anything of much

importance can be adduced. Aristotle, however, does make an interesting

reference to what may be brass (see note on p. 410), and there can be no

doubt that if we had the lost work of Aristotle's successor,

Theophrastus (372-288 B.C.), on metals we should be in possession of the

first adequate work on metallurgy. As it is, we find the green and blue

copper minerals from Cyprus mentioned in his "Stones." And this is the

first mention of any particular copper ore. He also mentions (XIX.)

pyrites "which melt," but whether it was a copper variety cannot be

determined. Theophrastus further describes the making of verdigris (see

note 4, p. 440). From Dioscorides we get a good deal of light on copper

treatment, but as his objective was to describe medicinal preparations,

the information is very indirect. He states (V, 100) that "pyrites is a

stone from which copper is made." He mentions _chalcitis_ (copper

sulphide, see note on, p. 573); while his _misy_, _sory_, _melanteria_,

_caeruleum_, and _chrysocolla_ were all oxidation copper or iron

minerals. (See notes on p. 573.) In giving a method of securing

_pompholyx_ (zinc oxide), "the soot flies up when the copper refiners

sprinkle powdered _cadmia_ over the molten metal" (see note 26, p. 394);

he indirectly gives us the first definite indication of making brass,

and further gives some details as to the furnaces there employed, which

embraced bellows and dust chambers. In describing the making of flowers

of copper (see note 26, p. 538) he states that in refining copper, when

the "molten metal flows through its tube into a receptacle, the workmen

pour cold water on it, the copper spits and throws off the flowers." He

gives the first description of vitriol (see note 11, p. 572), and

describes the pieces as "shaped like dice which stick together in

bunches like grapes." Altogether, from Dioscorides we learn for the

first time of copper made from sulphide ores, and of the recovery of

zinc oxides from furnace fumes; and he gives us the first certain

description of making brass, and finally the first notice of blue

vitriol.

The next author we have who gives any technical detail of copper work is

Pliny (23-79 A.D.), and while his statements carry us a little further

than Dioscorides, they are not as complete as the same number of words

could have afforded had he ever had practical contact with the subject,

and one is driven to the conclusion that he was not himself much of a

metallurgist. Pliny indicates that copper ores were obtained from veins

by underground mining. He gives the same minerals as Dioscorides, but is

a good deal confused over _chrysocolla_ and _chalcitis_. He gives no

description of the shapes of furnaces, but frequently mentions the

bellows, and speaks of the _cadmia_ and _pompholyx_ which adhered to the

walls and arches of the furnaces. He has nothing to say as to whether

fluxes are used or not. As to fuel, he says (XXXIII, 30) that "for

smelting copper and iron pine wood is the best." The following (XXXIV,

20) is of the greatest interest on the subject:--"Cyprian copper is

known as _coronarium_ and _regulare_; both are ductile.... In other

mines are made that known as _regulare_ and _caldarium_. These differ,

because the _caldarium_ is only melted, and is brittle to the hammer;

whereas the _regulare_ is malleable or ductile. All Cyprian copper is

this latter kind. But in other mines with care the difference can be

eliminated from _caldarium_, the impurities being carefully purged away

by smelting with fire, it is made into _regulare_. Among the remaining

kinds of copper the best is that of Campania, which is most esteemed for

vessels and utensils. This kind is made in several ways. At Capua it is

melted with wood, not with charcoal, after which it is sprinkled with

water and washed through an oak sieve. After it is melted a number of

times Spanish _plumbum argentum_ (probably pewter) is added to it in

proportion of ten pounds of the lead to one hundred pounds of copper,

and thereby it is made pliable and assumes that pleasing colour which in

other kinds of copper is effected by oil and the sun. In many parts of

the Italian provinces they make a similar kind of metal; but there they

add eight pounds of lead, and it is re-melted over charcoal because of

the scarcity of wood. Very different is the method carried on in Gaul,

particularly where the ore is smelted between red hot stones, for this

burns the metal and renders it black and brittle. Moreover, it is

re-melted only a single time, whereas the oftener this operation is

repeated the better the quality becomes. It is well to remark that all

copper fuses best when the weather is intensely cold." The red hot

stones in Gaul were probably as much figments of imagination as was the

assumption of one commentator that they were a reverberatory furnace.

Apart from the above, Pliny says nothing very direct on refining copper.

It is obvious that more than one melting was practised, but that

anything was known of the nature of oxidation by a blast and reduction

by poling is uncertain. We produce the three following statements in

connection with some bye-products used for medicinal purposes, which at

least indicate operations subsequent to the original melting. As to

whether they represent this species of refining or not, we leave it to

the metallurgical profession (XXXIV, 24):--"The flowers of copper are

used in medicine; they are made by fusing copper and moving it to

another furnace, where the rapid blast separates it into a thousand

particles, which are called flowers. These scales are also made when the

copper cakes are cooled in water (XXXIV, 35). _Smega_ is prepared in the

copper works; when the metal is melted and thoroughly smelted charcoal

is added to it and gradually kindled; after this, being blown upon by a

powerful bellows, it spits out, as it were, copper chaff (XXXIV, 37).

There is another product of these works easily distinguished from

_smega_, which the Greeks call _diphrygum_. This substance has three

different origins.... A third way of making it is from the residues

which fall to the bottom in copper furnaces. The difference between the

different substances (in the furnace) is that the copper itself flows

into a receiver; the slag makes its escape from the furnace; the flowers

float on the top (of the copper?), and the _diphrygum_ remains behind.

Some say that in the furnace there are certain masses of stone which,

being smelted, become soldered together, and that the copper fuses

around it, the mass not becoming liquid unless it is transferred to

another furnace. It thus forms a sort of knot, as it were, in the

metal."

Pliny is a good deal confused over the copper alloys, failing to

recognise _aurichalcum_ as the same product as that made by mixing

_cadmia_ and molten copper. Further, there is always the difficulty in

translation arising from the fact that the Latin _aes_ was

indiscriminately copper, brass, and bronze. He does not, except in one

instance (XXXIV., 2), directly describe the mixture of _cadmia_ and

copper. "Next to Livian (copper) this kind (_corduban_, from Spain) most

readily absorbs _cadmia_, and becomes almost as excellent as

_aurichalcum_ for making _sesterces_." As to bronze, there is no very

definite statement; but the _argentatium_ given in the quotation above

from XXXIV, 20, is stated in XXXIV, 48, to be a mixture of tin and lead.

The Romans carried on most extensive copper mining in various parts of

their empire; these activities extended from Egypt through Cyprus,

Central Europe, the Spanish Peninsula, and Britain. The activity of such

works is abundantly evidenced in the mines, but very little remains upon

the surface to indicate the equipment; thus, while mining methods are

clear enough, the metallurgy receives little help from these sources. At

Rio Tinto there still remain enormous slag heaps from the Romans, and

the Phoenician miners before them. Professor W. A. Carlyle informs us

that the ore worked must have been almost exclusively sulphides, as only

negligible quantities of carbonates exist in the deposits; they probably

mixed basic and siliceous ores. There is some evidence of roasting, and

the slags run from .2 to .6%. They must have run down mattes, but as to

how they ultimately arrived at metallic copper there is no evidence to

show.

The special processes for separating other metals from copper by

liquation and matting, or of refining by poling, etc., are none of them

clearly indicated in records or remains until we reach the 12th century.

Here we find very adequate descriptions of copper smelting and refining

by the Monk Theophilus (see Appendix B). We reproduce two paragraphs of

interest from Hendrie's excellent translation (p. 305 and 313): "Copper

is engendered in the earth. When a vein of which is found, it is

acquired with the greatest labour by digging and breaking. It is a stone

of a green colour and most hard, and naturally mixed with lead. This

stone, dug up in abundance, is placed upon a pile and burned after the

manner of chalk, nor does it change colour, but yet loses its hardness,

so that it can be broken up. Then, being bruised small, it is placed in

the furnace; coals and the bellows being applied, it is incessantly

forged by day and night. This should be done carefully and with caution;

that is, at first coals are placed in, then small pieces of stone are

distributed over them, and again coals, and then stone anew, and it is

thus arranged until it is sufficient for the size of the furnace. And

when the stone has commenced to liquefy, the lead flows out through some

small cavities, and the copper remains within. (313) Of the purification

of copper. Take an iron dish of the size you wish, and line it inside

and out with clay strongly beaten and mixed, and it is carefully dried.

Then place it before a forge upon the coals, so that when the bellows

act upon it the wind may issue partly within and partly above it, and

not below it. And very small coals being placed round it, place copper

in it equally, and add over it a heap of coals. When, by blowing a long

time, this has become melted, uncover it and cast immediately fine ashes

of coals over it, and stir it with a thin and dry piece of wood as if

mixing it, and you will directly see the burnt lead adhere to these

ashes like a glue. Which being cast out again superpose coals, and

blowing for a long time, as at first, again uncover it, and then do as

you did before. You do this until at length, by cooking it, you can

withdraw the lead entirely. Then pour it over the mould which you have

prepared for this, and you will thus prove if it be pure. Hold it with

pincers, glowing as it is, before it has become cold, and strike it with

a large hammer strongly over the anvil, and if it be broken or split you

must liquefy it anew as before."

The next writer of importance was Biringuccio, who was contemporaneous

with Agricola, but whose book precedes _De Re Metallica_ by 15 years.

That author (III, 2) is the first to describe particularly the furnace

used in Saxony and the roasting prior to smelting, and the first to

mention fluxes in detail. He, however, describes nothing of matte

smelting; in copper refining he gives the whole process of poling, but

omits the pole. It is not until we reach _De Re Metallica_ that we find

adequate descriptions of the copper minerals, roasting, matte smelting,

liquation, and refining, with a wealth of detail which eliminates the

necessity for a large amount of conjecture regarding technical methods

of the time.

[43] _Cadmia metallica fossilis_ (see note on p. 112). This was

undoubtedly the complex cobalt-arsenic-zinc minerals found in Saxony. In

the German translation, however, this is given as _Kalmey_, calamine,

which is unlikely from the association with pyrites.

[44] The Roman _modius_ (_modulus_?) held about 550 cubic inches, the

English peck holding 535 cubic inches. Then, perhaps, his seven _moduli_

would be roughly, 1 bushel 3 pecks, and 18 vessels full would be about

31 bushels--say, roughly, 5,400 lbs. of ore.

[45] Exhausted liquation cakes (_panes aerei fathiscentes_). This is the

copper sponge resulting from the first liquation of lead, and still

contains a considerable amount of lead. The liquation process is

discussed in great detail in Book XI.

[46] The method of this paragraph involves two main objectives--first,

the gradual enrichment of matte to blister copper; and, second, the

creation of large cakes of copper-lead-silver alloy of suitable size and

ratio of metals for liquation. This latter process is described in

detail in Book XI. The following groupings show the circuit of the

various products, the "lbs." being Roman _librae_:--

CHARGE. PRODUCTS.

{ Crude ore 5,400 lbs. } Primary matte (1) 600 lbs.

{ Lead slags 3 cartloads }

1st { Schist 1 cartload } Silver-copper alloy (A) 50 "

{ Flux 20 lbs. }

{ Concentrates from } Slags (B)

{ slags & accretions Small quantity }

{ Primary matte (1) 1,800 lbs. } Secondary matte (2) 1,800 lbs.

{ Hearth-lead & litharge 1,200 " }

{ Lead ore 300 " } Silver-copper-lead

2nd { Rich hard cakes (A_{4}) 500 " } alloy (liquation

{ Liquated cakes 200 " } cakes) (A_{2}) 1,200 "

{ Slags (B) }

{ Concentrates from } Slags (B_{2})

{ accretions }

{ Secondary matte (2) 1,800 lbs. } Tertiary matte (3) 1,300 lbs.

{ Hearth-lead & litharge 1,200 " } Silver-copper-lead

{ Lead ore 300 " } alloy (liquation

3rd { Rich hard cakes (A_{4}) 500 " } cakes) (A_{3}) 1,100 "

{ Slags (B_{2}) } Slags (B_{3})

{ Concentrates from }

{ accretions }

{ Tertiary matte (3) 11 cartloads } Quaternary hard cakes

{ Poor hard cakes (A_{5}) 3 " } matte (4) 2,000 lbs.

4th { Slags (B_{3}) } Rich hard cakes of

{ Concentrates from } matte (A_{4}) 1,500 "

{ accretions }

{ Roasted quartz } Poor hard cakes of

5th { Matte (4) (three } matte (A_{5}) 1,500 lbs.

{ times roasted) 11 cartloads } Final cakes of matte (5)

6th Final matte three times roasted is smelted to blister copper.

The following would be a rough approximation of the value of the various

products:--

(1.) Primary matte = 158 ounces troy per short ton.

(2.) Secondary matte = 85 " " "

(3.) Tertiary matte = 60 " " "

(4.) Quaternary matte = Indeterminate.

A. Copper-silver alloy = 388 ounces Troy per short ton.

A_{2} Copper-silver-lead alloy = 145 " " "

A_{3} " " " = 109 " " "

A_{4} Rich hard cakes = 97 " " "

A_{5} Poor hard cakes = Indeterminate.

Final blister copper = 12 ozs. Troy per short ton.

[47] This expression is usually used for hearth-lead, but in this case

the author is apparently confining himself to lead ore, and apparently

refers to lead carbonates. The German Translation gives _pleyschweiss_.

The pyrites mentioned in this paragraph may mean galena, as pyrites was

to Agricola a sort of genera.

[48] (_Excoquitur_) ... "_si vero pyrites, primo e fornace, ut

Goselariae videre licet, in catinum defluit liquor quidam candidus,

argento inimicus et nocivus; id enim comburit: quo circa recrementis,

quae supernatant, detractis effunditur: vel induratus conto uncinato

extrahitur: eundem liquorem parietes fornacis exudant._" In the Glossary

the following statement appears: "_Liquor candidus primo e fornace

defluens cum Goselariae excoquitur pyrites,--kobelt; quem parietes

fornacis exudant,--conterfei._" In this latter statement Agricola

apparently recognised that there were two different substances, _i.e._,

that the substance found in the furnace walls--_conterfei_--was not the

same substance as that which first flowed from the furnace--_kobelt_. We

are at no difficulty in recognizing _conterfei_ as metallic zinc; it was

long known by that term, and this accidental occurrence is repeatedly

mentioned by other authors after Agricola. The substance which first

flowed into the forehearth presents greater difficulties; it certainly

was not zinc. In _De Natura Fossilium_ (p. 347), Agricola says that at

Goslar the lead has a certain white slag floating upon it, the "colour

derived from the pyrites (_pyriten argenteum_) from which it was

produced." _Pyriten argenteum_ was either marcasite or mispickel,

neither of which offers much suggestion; nor are we able to hazard an

explanation of value.

HISTORICAL NOTE ON ZINC. The history of zinc metallurgy falls into two

distinct lines--first, that of the metal, and second, that of zinc ore,

for the latter was known and used to make brass by cementation with

copper and to yield oxides by sublimation for medicinal purposes, nearly

2,000 years before the metal became generally known and used in Europe.

There is some reason to believe that metallic zinc was known to the

Ancients, for bracelets made of it, found in the ruins of Cameros (prior

to 500 B.C.), may have been of that age (Raoul Jagnaux, _Traite de

Chimie Generale_, 1887, II, 385); and further, a passage in Strabo (63

B.C.-24 A.D.) is of much interest. He states: (XIII, 1, 56) "There is

found at Andeira a stone which when burnt becomes iron. It is then put

into a furnace, together with some kind of earth, when it distils a mock

silver (_pseudargyrum_), or with the addition of copper it becomes the

compound called _orichalcum_. There is found a mock silver near Tismolu

also." (Hamilton's Trans., II, p. 381). About the Christian era the

terms _orichalcum_ or _aurichalcum_ undoubtedly refer to brass, but

whether these terms as used by earlier Greek writers do not refer to

bronze only, is a matter of considerable doubt. Beyond these slight

references we are without information until the 16th Century. If the

metal was known to the Ancients it must have been locally, for by its

greater adaptability to brass-making it would probably have supplanted

the crude melting of copper with zinc minerals.

It appears that the metal may have been known in the Far East prior to

such knowledge in Europe; metallic zinc was imported in considerable

quantities from the East as early as the 16th and 17th centuries under

such terms as _tuteneque_, _tuttanego_, _calaem_, and _spiauter_--the

latter, of course, being the progenitor of our term spelter. The

localities of Eastern production have never been adequately

investigated. W. Hommel (Engineering and Mining Journal, June 15, 1912)

gives a very satisfactory review of the Eastern literature upon the

subject, and considers that the origin of manufacture was in India,

although the most of the 16th and 17th Century product came from China.

The earliest certain description seems to be some recipes for

manufacture quoted by Praphulla Chandra Ray (A History of Hindu

Chemistry, London, 1902, p. 39) dating from the 11th to the 14th

Centuries. There does not appear to be any satisfactory description of

the Chinese method until that of Sir George Staunton (Journal Asiatique

Paris, 1835, p. 141.) We may add that spelter was produced in India by

crude distillation of calamine in clay pots in the early part of the

19th Century (Brooke, Jour. Asiatic Soc. of Bengal, vol. XIX, 1850, p.

212), and the remains of such smelting in Rajputana are supposed to be

very ancient.

The discovery of zinc in Europe seems to have been quite independent of

the East, but precisely where and when is clouded with much uncertainty.

The _marchasita aurea_ of Albertus Magnus has been called upon to serve

as metallic zinc, but such belief requires a hypothesis based upon a

great deal of assumption. Further, the statement is frequently made that

zinc is mentioned in Basil Valentine's Triumphant Chariot of Antimony

(the only one of the works attributed to this author which may date

prior to the 17th Century), but we have been unable to find any such

reference. The first certain mention of metallic zinc is generally

accredited to Paracelsus (1493-1541), who states (_Liber Mineralium_

II.): "Moreover there is another metal generally unknown called

_zinken_. It is of peculiar nature and origin; many other metals

adulterate it. It can be melted, for it is generated from three fluid

principles; it is not malleable. Its colour is different from other

metals and does not resemble others in its growth. Its ultimate matter

(_ultima materia_) is not to me yet fully known. It admits of no mixture

and does not permit of the _fabricationes_ of other metals. It stands

alone entirely to itself." We do not believe that this book was

published until after Agricola's works. Agricola introduced the

following statements into his revised edition of _Bermannus_ (p. 431),

published in 1558: "It (a variety of pyrites) is almost the colour of

galena, but of entirely different components. From it there is made gold

and silver, and a great quantity is dug in Reichenstein, which is in

Silesia, as was recently reported to me. Much more is found at Raurici,

which they call _zincum_, which species differs from pyrites, for the

latter contains more silver than gold, the former only gold or hardly

any silver." In _De Natura Fossilium_ (p. 368): "For this _cadmia_ is

put, in the same way as quicksilver, in a suitable vessel so that the

heat of the fire will cause it to sublime, and from it is made a black

or brown or grey body which the Alchemists call _cadmia sublimata_. This

possesses corrosive properties to the highest degree. Cognate with this

_cadmia_ and pyrites is a compound which the Noricans and Rhetians call

_zincum_." We leave it to readers to decide how near this comes to

metallic zinc; in any event, he apparently did not recognise his

_conterfei_ from the furnaces as the same substance as the _zincum_ from

Silesia. The first correlation of these substances was apparently by

Lohneys, in 1617, who says (_Vom Bergwerk_, p. 83-4): "When the people

in the smelting works are smelting, there is made under the furnace and

in the cracks in the walls among the badly plastered stones, a metal

which is called _zinc_ or _counterfeht_, and when the wall is scraped it

falls into a vessel placed to receive it. This metal greatly resembles

tin, but it is harder and less malleable.... The Alchemists have a great

desire for this _zinc_ or bismuth." That this metal originated from

blende or calamine was not recognised until long after, and Libavis

(_Alchymia_, Frankfort, 1606), in describing specimens which came from

the East, did not so identify it, this office being performed by

Glauber, who says (_De Prosperitate Germanias_, Amsterdam, 1656): "Zink

is a volatile mineral or half-ripe metal when it is extracted from its

ore. It is more brilliant than tin and not so fusible or malleable ...

it turns (copper) into brass, as does _lapis calaminaris_, for indeed

this stone is nothing but infusible zinc, and this zinc might be called

a fusible _lapis calaminaris_, inasmuch as both of them partake of the

same nature.... It sublimates itself up into the cracks of the furnace,

whereupon the smelters frequently break it out." The systematic

distillation of zinc from calamine was not discovered in Europe until

the 18th Century. Henkel is generally accredited with the first

statement to that effect. In a contribution published as an Appendix to

his other works, of which we have had access only to a French

translation (_Pyritologie_, Paris, 1760, p. 494), he concludes that zinc

is a half-metal of which the best ore is calamine, but believes it is

always associated with lead, and mentions that an Englishman lately

arrived from Bristol had seen it being obtained from calamine in his own

country. He further mentions that it can be obtained by heating calamine

and lead ore mixed with coal in a thick earthen vessel. The Bristol

works were apparently those of John Champion, established about 1740.

The art of distillation was probably learned in the East.

Definite information as to the zinc minerals goes back to but a little

before the Christian Era, unless we accept nebular references to

_aurichalcum_ by the poets, or what is possibly zinc ore in the "earth"

mentioned by Aristotle (_De Mirabilibus_, 62): "Men say that the copper

of the Mossynoeci is very brilliant and white, no tin being mixed with

it; but there is a kind of earth there which is melted with it." This

might quite well be an arsenical mineral. But whether we can accept the

poets or Aristotle or the remark of Strabo given above, as sufficient

evidence or not, there is no difficulty with the description of _cadmia_

and _pompholyx_ and _spodos_ of Dioscorides (1st Century), parts of

which we reproduce in note 26, p. 394. His _cadmia_ is described as

rising from the copper furnaces and clinging to the iron bars, but he

continues: "_Cadmia_ is also prepared by burning the stone called

pyrites, which is found near Mt. Soloi in Cyprus.... Some say that

_cadmia_ may also be found in stone quarries, but they are deceived by

stones having a resemblance to _cadmia_." _Pompholyx_ and _spodos_ are

evidently furnace calamine. From reading the quotation given on p. 394,

there can be no doubt that these materials, natural or artificial, were

used to make brass, for he states (V, 46): "White _pompholyx_ is made

every time that the artificer in the working and perfecting of the

copper sprinkles powdered _cadmia_ upon it to make it more perfect, the

soot arising from this ... is _pompholyx_." Pliny is confused between

the mineral _cadmia_ and furnace _calamine_, and none of his statements

are very direct on the subject of brass making. His most pointed

statement is (XXXIV, 2): "... Next to Livian (copper) this kind best

absorbs _cadmia_, and is almost as good as _aurichalcum_ for making

sesterces and double asses." As stated above, there can be little doubt

that the _aurichalcum_ of the Christian Era was brass, and further, we

do know of brass sesterces of this period. Other Roman writers of this

and later periods refer to earth used with copper for making brass.

Apart from these evidences, however, there is the evidence of analyses

of coins and objects, the earliest of which appears to be a large brass

of the Cassia family of 20 B.C., analyzed by Phillips, who found 17.3%

zinc (Records of Mining and Metallurgy, London, 1857, p. 13). Numerous

analyses of coins and other objects dating during the following century

corroborate the general use of brass. Professor Gowland (Presidential

Address, Inst. of Metals, 1912) rightly considers the Romans were the

first to make brass, and at about the above period, for there appears to

be no certainty of any earlier production. The first adequate technical

description of brass making is in about 1200 A.D. being that of

Theophilus, who describes (Hendrie's Trans., p. 307) calcining

_calamina_ and mixing it with finely divided copper in glowing

crucibles. The process was repeated by adding more calamine and copper

until the pots were full of molten metal. This method is repeatedly

described with minor variations by Biringuccio, Agricola (_De Nat.

Fos._), and others, down to the 18th Century. For discussion of the zinc

minerals see note on p. 112.

[49] "_... non raro, ut nonnulli pyritae sunt, candida...._" This is

apparently the unknown substance mentioned above.

[50] One _drachma_ is about 3 ounces Troy per short ton. Three _unciae_

are about 72 ounces 6 dwts. Troy per short ton.

[51] In this section, which treats of the metallurgy of _plumbum

candidum_, "tin," the word _candidum_ is very often omitted in the

Latin, leaving only _plumbum_, which is confusing at times with lead.

The black tin-stone, _lapilli nigri_ has been treated in a similar

manner, _lapilli_ (small stones) constantly occurring alone in the

Latin. This has been rendered as "tin-stone" throughout, and the

material prior to extraction of the _lapilli nigri_ has been rendered

"tin-stuff," after the Cornish.

[52] "_... ex saxis vilibus, quae natura de diversa materia composuit._"

The Glossary gives _grindstein_. Granite (?).

[53] HISTORICAL NOTES ON TIN METALLURGY. The first appearance of tin

lies in the ancient bronzes. And while much is written upon the "Bronze

Age" by archaeologists, we seriously doubt whether or not a large part of

so-called bronze is not copper. In any event, this period varied with

each race, and for instance, in Britain may have been much later than

Egyptian historic times. The bronze articles of the IV Dynasty (from

3800 to 4700 B.C. depending on the authority) place us on certain ground

of antiquity. Professor Gowland (Presidential Address, Inst. of Metals,

London, 1912) maintains that the early bronzes were the result of direct

smelting of stanniferous copper ores, and while this may be partially

true for Western Europe, the distribution and nature of the copper

deposits do not warrant this assumption for the earlier scenes of human

activity--Asia Minor, Egypt, and India. Further, the lumps of rough tin

and also of copper found by Borlase (Tin Mining in Spain, Past and

Present, London, 1897, p. 25) in Cornwall, mixed with bronze celts under

conditions certainly indicating the Bronze Age, is in itself of

considerable evidence of independent melting. To our mind the vast

majority of ancient bronzes must have been made from copper and tin

mined and smelted independently. As to the source of supply of ancient

tin, we are on clear ground only with the advent of the Phoenicians,

1500-1000 B.C., who, as is well known, distributed to the ancient world

a supply from Spain and Britain. What the source may have been prior to

this time has been subject to much discussion, and while some slender

threads indicate the East, we believe that a more local supply to Egypt,

etc., is not impossible. The discovery of large tin fields in Central

Africa and the native-made tin ornaments in circulation among the

negroes, made possible the entrance of the metal into Egypt along the

trade routes. Further, we see no reason why alluvial tin may not have

existed within easy reach and have become exhausted. How quickly such a

source of metal supply can be forgotten and no evidence remain, is

indicated by the seldom remembered alluvial gold supply from Ireland.

However, be these conjectures as they may, the East has long been the

scene of tin production and of transportation activity. Among the

slender evidences that point in this direction is that the Sanskrit term

for tin is _kastira_, a term also employed by the Chaldeans, and

represented in Arabic by _kasdir_, and it may have been the progenitor

of the Greek _cassiteros_. There can be no doubt that the Phoenicians

also traded with Malacca, etc., but beyond these threads there is little

to prove the pre-western source. The strained argument of Beckmann

(Hist. of Inventions, vol. II., p. 207) that the _cassiteros_ of Homer

and the _bedil_ of the Hebrews was possibly not tin, and that tin was

unknown at this time, falls to the ground in the face of the vast amount

of tin which must have been in circulation to account for the bronze

used over a period 2,000 years prior to those peoples. Tin is early

mentioned in the Scriptures (Numbers XXXI, 22), being enumerated among

the spoil of the Midianites (1200 B.C.?), also Ezekiel (600 B.C., XXVII,

12) speaks of tin from Tarshish (the Phoenician settlement on the

coast of Spain). According to Homer tin played considerable part in

Vulcan's metallurgical stores. Even approximately at what period the

Phoenicians began their distribution from Spain and Britain cannot be

determined. They apparently established their settlements at Gades

(Cadiz) in Tarshish, beyond Gibraltar, about 1100 B.C. The remains of

tin mining in the Spanish peninsula prior to the Christian Era indicate

most extensive production by the Phoenicians, but there is little

evidence as to either mining or smelting methods. Generally as to the

technical methods of mining and smelting tin, we are practically without

any satisfactory statement down to Agricola. However, such scraps of

information as are available are those in Homer (see note on p. 402),

Diodorus, and Pliny.

Diodorus says (V, 2) regarding tin in Spain: "They dig it up, and melt

it down in the same way as they do gold and silver;" and again, speaking

of the tin in Britain, he says: "These people make tin, which they dig

up with a great deal of care and labour; being rocky, the metal is mixed

with earth, out of which they melt the metal, and then refine it." Pliny

(XXXIV, 47), in the well-known and much-disputed passage: "Next to be

considered are the characteristics of lead, which is of two kinds, black

and white. The most valuable is the white; the Greeks called it

_cassiteros_, and there is a fabulous story of its being searched for

and carried from the islands of Atlantis in barks covered with hides.

Certainly it is obtained in Lusitania and Gallaecia on the surface of

the earth from black-coloured sand. It is discovered by its great

weight, and it is mixed with small pebbles in the dried beds of

torrents. The miners wash these sands, and that which settles they heat

in the furnace. It is also found in gold mines, which are called

_alutiae_. A stream of water passing through detaches small black

pebbles variegated with white spots, the weight of which is the same as

gold. Hence it is that they remain in the baskets of the gold collectors

with the gold; afterward, they are separated in a _camillum_ and when

melted become white lead."

There is practically no reference to the methods of Cornish tin-working

over the whole period of 2,000 years that mining operations were carried

on there prior to the Norman occupation. From then until Agricola's

time, a period of some four centuries, there are occasional references

in Stannary Court proceedings, Charters, and such-like official

documents which give little metallurgical insight. From a letter of

William de Wrotham, Lord Warden of the Stannaries, in 1198, setting out

the regulations for the impost on tin, it is evident that the black tin

was smelted once at the mines and that a second smelting or refining was

carried out in specified towns under the observation of the Crown

Officials. In many other official documents there are repeated

references to the right to dig turfs and cut wood for smelting the tin.

Under note 8, p. 282, we give some further information on tin

concentration, and the relation of Cornish and German tin miners.

Biringuccio (1540) gives very little information on tin metallurgy, and

we are brought to _De Re Metallica_ for the first clear exposition.

As to the description on these pages it must be remembered that the

tin-stone has been already roasted, thus removing some volatile

impurities and oxidizing others, as described on page 348. The furnaces

and the methods of working the tin, here described, are almost identical

with those in use in Saxony to-day. In general, since Agricola's time

tin has not seen the mechanical and metallurgical development of the

other metals. The comparatively small quantities to be dealt with; the

necessity of maintaining a strong reducing atmosphere, and consequently

a mild cold blast; and the comparatively low temperature demanded, gave

little impetus to other than crude appliances until very modern times.

[54] _Aureo nummo_. German Translation gives _reinschen guelden_, which

was the equivalent of about $1.66, or 6.9 shillings. The purchasing

power of money was, however, several times as great as at present.

[55] In the following descriptions of iron-smelting, we have three

processes described; the first being the direct reduction of malleable

iron from ore, the second the transition stage then in progress from the

direct to indirect method by way of cast-iron; and the third a method of

making steel by cementation. The first method is that of primitive

iron-workers of all times and all races, and requires little comment. A

pasty mass was produced, which was subsequently hammered to make it

exude the slag, the hammered mass being the ancient "bloom." The second

process is of considerable interest, for it marks one of the earliest

descriptions of working iron in "a furnace similar to a blast furnace,

but much wider and higher." This original German _Stueckofen_ or high

bloomery furnace was used for making "masses" of wrought-iron under

essentially the same conditions as its progenitor the forge--only upon a

larger scale. With high temperatures, however, such a furnace would, if

desired, yield molten metal, and thus the step to cast-iron as a

preliminary to wrought-iron became very easy and natural, in fact

Agricola mentions above that if the iron is left to settle in the

furnace it becomes hard. The making of malleable iron by subsequent

treatment of the cast-iron--the indirect method--originated in about

Agricola's time, and marks the beginning of one of those subtle economic

currents destined to have the widest bearing upon civilization. It is to

us uncertain whether he really understood the double treatment or not.

In the above paragraph he says from ore "once or twice smelted they make

iron," etc., and in _De Natura Fossilium_ (p. 339) some reference is

made to pouring melted iron, all of which would appear to be cast-iron.

He does not, however, describe the 16th Century method of converting

cast into wrought iron by way of in effect roasting the pig iron to

eliminate carbon by oxidation, with subsequent melting into a "ball" or

"mass." It must be borne in mind that puddling for this purpose did not

come into use until the end of the 18th Century. A great deal of

discussion has arisen as to where and at what time cast-iron was made

systematically, but without satisfactory answer; in any event, it seems

to have been in about the end of the 14th Century, as cast cannon began

to appear about that time. It is our impression that the whole of this

discussion on iron in _De Re Metallica_ is an abstract from Biringuccio,

who wrote 15 years earlier, as it is in so nearly identical terms. Those

interested will find a translation of Biringuccio's statement with

regard to steel in Percy's Metallurgy of Iron and Steel, London, 1864,

p. 807.

HISTORICAL NOTE ON IRON SMELTING. The archaeologists' division of the

history of racial development into the Stone, Bronze, and Iron Ages,

based upon objects found in tumuli, burial places, etc., would on the

face of it indicate the prior discovery of copper metallurgy over iron,

and it is generally so maintained by those scientists. The metallurgists

have not hesitated to protest that while this distinction of "Ages" may

serve the archaeologists, and no doubt represents the sequence in which

the metal objects are found, yet it by no means follows that this was

the order of their discovery or use, but that iron by its rapidity of

oxidation has simply not been preserved. The arguments which may be

advanced from our side are in the main these. Iron ore is of more

frequent occurrence than copper ores, and the necessary reduction of

copper oxides (as most surface ores must have been) to fluid metal

requires a temperature very much higher than does the reduction of iron

oxides to wrought-iron blooms, which do not necessitate fusion. The

comparatively greater simplicity of iron metallurgy under primitive

conditions is well exemplified by the hill tribes of Northern Nigeria,

where in village forges the negroes reduce iron sufficient for their

needs, from hematite. Copper alone would not be a very serviceable metal

to primitive man, and he early made the advance to bronze; this latter

metal requires three metallurgical operations, and presents immeasurably

greater difficulties than iron. It is, as Professor Gowland has

demonstrated (Presidential Address, Inst. of Metals, London, 1912) quite

possible to make bronze from melting stanniferous copper ores, yet such

combined occurrence at the surface is rare, and, so far as known, the

copper sources from which Asia Minor and Egypt obtained their supply do

not contain tin. It seems to us, therefore, that in most cases the

separate fusions of different ores and their subsequent re-melting were

required to make bronze. The arguments advanced by the archaeologists

bear mostly upon the fact that, had iron been known, its superiority

would have caused the primitive races to adopt it, and we should not

find such an abundance of bronze tools. As to this, it may be said that

bronze weapons and tools are plentiful enough in Egyptian, Mycenaean, and

early Greek remains, long after iron was demonstrably well known. There

has been a good deal pronounced by etymologists on the history of iron

and copper, for instance, by Max Mueller, (Lectures on the Science of

Language, Vol. II, p. 255, London, 1864), and many others, but the

amazing lack of metallurgical knowledge nullifies practically all their

conclusions. The oldest Egyptian texts extant, dating 3500 B.C., refer

to iron, and there is in the British Museum a piece of iron found in the

Pyramid of Kephron (3700 B.C.) under conditions indicating its

co-incident origin. There is exhibited also a fragment of oxidized iron

lately found by Professor Petrie and placed as of the VI Dynasty (B.C.

3200). Despite this evidence of an early knowledge of iron, there is

almost a total absence of Egyptian iron objects for a long period

subsequent to that time, which in a measure confirms the view of its

disappearance rather than that of ignorance of it. Many writers have

assumed that the Ancients must have had some superior art of hardening

copper or bronze, because the cutting of the gigantic stonework of the

time could not have been done with that alloy as we know it; no such

hardening appears among the bronze tools found, and it seems to us that

the argument is stronger that the oldest Egyptian stoneworkers employed

mostly iron tools, and that these have oxidized out of existence. The

reasons for preferring copper alloys to iron for decorative objects were

equally strong in ancient times as in the present day, and accounts

sufficiently for these articles, and, therefore, iron would be devoted

to more humble objects less likely to be preserved. Further, the

Egyptians at a later date had some prejudices against iron for sacred

purposes, and the media of preservation of most metal objects were not

open to iron. We know practically nothing of very early Egyptian

metallurgy, but in the time of Thotmes III. (1500 B.C.) bellows were

used upon the forge.

Of literary evidences the earliest is in the Shoo King among the Tribute

of Yue (2500 B.C.?). Iron is frequently mentioned in the Bible, but it is

doubtful if any of the early references apply to steel. There is

scarcely a Greek or Latin author who does not mention iron in some

connection, and of the earliest, none are so suggestive from a

metallurgical point of view as Homer, by whom "laboured" mass

(wrought-iron?) is often referred to. As, for instance, in the Odyssey

(I., 234) Pallas in the guise of Mentes, says according to Pope:

"Freighted with iron from my native land

I steer my voyage to the Brutian strand,

To gain by commerce for the laboured mass

A just proportion of refulgent brass."

(Brass is modern poetic licence for copper or bronze). Also, in the

Odyssey (IX, 465) when Homer describes how Ulysses plunged the stake

into Cyclop's eye, we have the first positive evidence of steel,

although hard iron mentioned in the Tribute of Yue, above referred to, is

sometimes given as steel:

"And as when armourers temper in the ford

The keen-edg'd pole-axe, or the shining sword,

The red-hot metal hisses in the lake."

No doubt early wrought-iron was made in the same manner as Agricola

describes. We are, however, not so clear as to the methods of making

steel. Under primitive methods of making wrought-iron it is quite

possible to carburize the iron sufficiently to make steel direct from

ore. The primitive method of India and Japan was to enclose lumps of

wrought-iron in sealed crucibles with charcoal and sawdust, and heat

them over a long period. Neither Pliny nor any of the other authors of

the period previous to the Christian Era give us much help on steel

metallurgy, although certain obscure expressions of Aristotle have been

called upon (for instance, St. John V. Day, Prehistoric Use of Iron and

Steel, London, 1877, p. 134) to prove its manufacture by immersing

wrought-iron in molten cast-iron.

[56] _Quae vel aerosa est, vel cocta_. It is by no means certain that

_cocta_, "cooked" is rightly translated, for the author has not hitherto

used this expression for heated. This may be residues from roasting and

leaching pyrites for vitriol, etc.

[57] Agricola draws no sharp line of distinction between antimony the

metal, and its sulphide. He uses the Roman term _stibi_ or _stibium_

(_Interpretatio_,--_Spiesglas_) throughout this book, and evidently in

most cases means the sulphide, but in others, particularly in parting

gold and silver, metallic antimony would be reduced out. We have been in

much doubt as to the term to introduce into the text, as the English

"stibnite" carries too much precision of meaning. Originally the

"antimony" of trade was the sulphide. Later, with the application of

that term to the metal, the sulphide was termed "grey antimony," and we

have either used _stibium_ for lack of better alternative, or adopted

"grey antimony." The method described by Agricola for treating antimony

sulphide is still used in the Harz, in Bohemia, and elsewhere. The

stibnite is liquated out at a low heat and drips from the upper to the

lower pot. The resulting purified antimony sulphide is the modern

commercial "crude antimony" or "grey antimony."

HISTORICAL NOTE ON THE METALLURGY OF ANTIMONY. The Egyptologists have

adopted the term "antimony" for certain cosmetics found in Egyptian

tombs from a very early period. We have, however, failed to find any

reliable analyses which warrant this assumption, and we believe that it

is based on the knowledge that antimony was used as a base for eye

ointments in Greek and Roman times, and not upon proper chemical

investigation. It may be that the ideograph which is interpreted as

antimony may really mean that substance, but we only protest that the

chemist should have been called in long since. In St. Jerome's

translation of the Bible, the cosmetic used by Jezebel (II. Kings IX,

30) and by the lady mentioned by Ezekiel (XXIII, 40), "who didst wash

thyself and paintedst thine eyes" is specifically given as _stibio_. Our

modern translation carries no hint of the composition of the cosmetic,

and whether some of the Greek or Hebrew MSS. do furnish a basis for such

translation we cannot say. The Hebrew term for this mineral was _kohl_,

which subsequently passed into "alcool" and "alkohol" in other

languages, and appears in the Spanish Bible in the above passage in

Ezekiel as _alcoholaste_. The term _antimonium_ seems to have been first

used in Latin editions of Geber published in the latter part of the 15th

Century. In any event, the metal is clearly mentioned by Dioscorides

(1st Century), who calls it _stimmi_, and Pliny, who termed it

_stibium_, and they leave no doubt that it was used as a cosmetic for

painting the eyebrows and dilating the eyes. Dioscorides (V, 59) says:

"The best _stimmi_ is very brilliant and radiant. When broken it divides

into layers with no part earthy or dirty; it is brittle. Some call it

_stimmi_, others _platyophthalmon_ (wide eyed); others _larbason_,

others _gynaekeion_ (feminine).... It is roasted in a ball of dough with

charcoal until it becomes a cinder.... It is also roasted by putting it

on live charcoal and blowing it. If it is roasted too much it becomes

lead." Pliny states (XXXIII, 33 and 34): "In the same mines in which

silver is found, properly speaking there is a stone froth. It is white

and shining, not transparent; is called _stimmi_, or _stibi_, or

_alabastrum_, and _larbasis_. There are two kinds of it, the male and

the female. The most approved is the female, the male being more uneven,

rougher, less heavy, not so radiant, and more gritty. The female kind is

bright and friable, laminar and not globular. It is astringent and

refrigerative, and its principal use is for the eyes.... It is burned in

manure in a furnace, is quenched with milk, ground with rain water in a

mortar, and while thus turbid it is poured into a copper vessel and

purified with nitrum ... above all in roasting it care should be taken

that it does not turn to lead." There can be little doubt from

Dioscorides' statement of its turning to lead that he had seen the metal

antimony, although he thought it a species of lead. Of further interest

in connection with the ancient knowledge of the metal is the Chaldean

vase made of antimony described by Berthelot (_Comptes Rendus_, 1887,

CIV, 265). It is possible that Agricola knew the metal, although he

gives no details as to de-sulphurizing it or for recovering the metal

itself. In _De Natura Fossilium_ (p. 181) he makes a statement which

would indicate the metal, "_Stibium_ when melted in the crucible and

refined has as much right to be regarded as a metal as is accorded to

lead by most writers. If when smelted a certain portion be added to tin,

a printer's alloy is made from which type is cast that is used by those

who print books." Basil Valentine, in his "Triumphal Chariot of

Antimony," gives a great deal that is new with regard to this metal,

even if we can accredit the work with no earlier origin than its

publication--about 1600; it seems possible however, that it was written

late in the 15th Century (see Appendix B). He describes the preparation

of the metal from the crude ore, both by roasting and reduction from the

oxide with argol and saltpetre, and also by fusing with metallic iron.

While the first description of these methods is usually attributed to

Valentine, it may be pointed out that in the _Probierbuechlein_ (1500) as

well as in Agricola the separation of silver from iron by antimony

sulphide implies the same reaction, and the separation of silver and

gold with antimony sulphide, often attributed to Valentine, is

repeatedly set out in the _Probierbuechlein_ and in _De Re Metallica_.

Biringuccio (1540) has nothing of importance to say as to the treatment

of antimonial ores, but mentions it as an alloy for bell-metal, which

would imply the metal.

[58] HISTORICAL NOTE ON THE METALLURGY OF QUICKSILVER. The earliest

mention of quicksilver appears to have been by Aristotle

(_Meteorologica_ IV, 8, 11), who speaks of it as fluid silver (_argyros

chytos_). Theophrastus (105) states: "Such is the production of

quicksilver, which has its uses. This is obtained from cinnabar rubbed

with vinegar in a brass mortar with a brass pestle." (Hill's Trans., p.

139). Theophrastus also (103) mentions cinnabar from Spain and

elsewhere. Dioscorides (V, 70) appears to be the first to describe the

recovery of quicksilver by distillation: "Quicksilver (_hydrargyros_,

_i.e._, liquid silver) is made from _ammion_, which is called

_cinnabari_. An iron bowl containing _cinnabari_ is put into an earthen

vessel and covered over with a cup-shaped lid smeared with clay. Then it

is set on a fire of coals and the soot which sticks to the cover when

wiped off and cooled is quicksilver. Quicksilver is also found in drops

falling from the walls of the silver mines. Some say there are

quicksilver mines. It can be kept only in vessels of glass, lead, tin

(?), or silver, for if put in vessels of any other substances it

consumes them and flows through." Pliny (XXXIII, 41): "There has been

discovered a way of extracting _hydrargyros_ from the inferior _minium_

as a substitute for quicksilver, as mentioned. There are two methods:

either by pounding _minium_ and vinegar in a brass mortar with a brass

pestle, or else by putting _minium_ into a flat earthen dish covered

with a lid, well luted with potter's clay. This is set in an iron pan

and a fire is then lighted under the pan, and continually blown by a

bellows. The perspiration collects on the lid and is wiped off and is

like silver in colour and as liquid as water." Pliny is somewhat

confused over the _minium_--or the text is corrupt, for this should be

the genuine _minium_ of Roman times. The methods of condensation on the

leaves of branches placed in a chamber, of condensing in ashes placed

over the mouth of the lower pot, and of distilling in a retort, are

referred to by Biringuccio (A.D. 1540), but with no detail.

[59] Most of these methods depend upon simple liquation of native

bismuth. The sulphides, oxides, etc., could not be obtained without

fusing in a furnace with appropriate de-sulphurizing or reducing agents,

to which Agricola dimly refers. In _Bermannus_ (p. 439), he says:

"_Bermannus_.--I will show you another kind of mineral which is numbered

amongst metals, but appears to me to have been unknown to the Ancients;

we call it _bisemutum_. _Naevius_.--Then in your opinion there are more

kinds of metals than the seven commonly believed? _Bermannus_.--More, I

consider; for this which just now I said we called _bisemutum_, cannot

correctly be called _plumbum candidum_ (tin) nor _nigrum_ (lead), but is

different from both, and is a third one. _Plumbum candidum_ is whiter

and _plumbum nigrum_ is darker, as you see. _Naevius_.--We see that this

is of the colour of _galena_. _Ancon_.--How then can _bisemutum_, as you

call it, be distinguished from _galena_? _Bermannus_.--Easily; when you

take it in your hands it stains them with black unless it is quite hard.

The hard kind is not friable like _galena_, but can be cut. It is

blacker than the kind of crude silver which we say is almost the colour

of lead, and thus is different from both. Indeed, it not rarely contains

some silver. It generally shows that there is silver beneath the place

where it is found, and because of this our miners are accustomed to call

it the 'roof of silver.' They are wont to roast this mineral, and from

the better part they make metal; from the poorer part they make a

pigment of a kind not to be despised." This pigment was cobalt blue (see

note on p. 112), indicating a considerable confusion of these minerals.

This quotation is the first description of bismuth, and the above text

the first description of bismuth treatment. There is, however, bare

mention of the mineral earlier, in the following single line from the

_Probierbuechlein_ (p. 1): "Jupiter (controls) the ores of tin and

_wismundt_." And it is noted in the _Nuetzliche Bergbuechlein_ in

association with silver (see Appendix B).

[60] This _cadmia_ is given in the German translation as _kobelt_. It is

probably the cobalt-arsenic-bismuth minerals common in Saxony. A large

portion of the world's supply of bismuth to-day comes from the cobalt

treatment works near Schneeberg. For further discussion of _cadmia_ see

note on p. 112.

BOOK X.

Questions as to the methods of smelting ores and of obtaining metals I

discussed in Book IX. Following this, I should explain in what manner

the precious metals are parted from the base metals, or on the other

hand the base metals from the precious[1]. Frequently two metals,

occasionally more than two, are melted out of one ore, because in nature

generally there is some amount of gold in silver and in copper, and some

silver in gold, copper, lead, and iron; likewise some copper in gold,

silver, lead, and iron, and some lead in silver; and lastly, some iron

in copper[2]. But I will begin with gold.

Gold is parted from silver, or likewise the latter from the former,

whether it be mixed by nature or by art, by means of _aqua valens_[3],

and by powders which consist of almost the same things as this _aqua_.

In order to preserve the sequence, I will first speak of the ingredients

of which this _aqua_ is made, then of the method of making it, then of

the manner in which gold is parted from silver or silver from gold.

Almost all these ingredients contain vitriol or alum, which, by

themselves, but much more when joined with saltpetre, are powerful to

part silver from gold. As to the other things that are added to them,

they cannot individually by their own strength and nature separate those

metals, but joined they are very powerful. Since there are many

combinations, I will set out a few. In the first, the use of which is

common and general, there is one _libra_ of vitriol and as much salt,

added to a third of a _libra_ of spring water. The second contains two

_librae_ of vitriol, one of saltpetre, and as much spring or river water

by weight as will pass away whilst the vitriol is being reduced to

powder by the fire. The third consists of four _librae_ of vitriol, two

and a half _librae_ of saltpetre, half a _libra_ of alum, and one and a

half _librae_ of spring water. The fourth consists of two _librae_ of

vitriol, as many _librae_ of saltpetre, one quarter of a _libra_ of

alum, and three-quarters of a _libra_ of spring water. The fifth is

composed of one _libra_ of saltpetre, three _librae_ of alum, half a

_libra_ of brick dust, and three-quarters of a _libra_ of spring water.

The sixth consists of four _librae_ of vitriol, three _librae_ of

saltpetre, one of alum, one _libra_ likewise of stones which when thrown

into a fierce furnace are easily liquefied by fire of the third order,

and one and a half _librae_ of spring water. The seventh is made of two

_librae_ of vitriol, one and a half _librae_ of saltpetre, half a

_libra_ of alum, and one _libra_ of stones which when thrown into a

glowing furnace are easily liquefied by fire of the third order, and

five-sixths of a _libra_ of spring water. The eighth is made of two

_librae_ of vitriol, the same number of _librae_ of saltpetre, one and a

half _librae_ of alum, one _libra_ of the lees of the _aqua_ which parts

gold from silver; and to each separate _libra_ a sixth of urine is

poured over it. The ninth contains two _librae_ of powder of baked

bricks, one _libra_ of vitriol, likewise one _libra_ of saltpetre, a

handful of salt, and three-quarters of a _libra_ of spring water. Only

the tenth lacks vitriol and alum, but it contains three _librae_ of

saltpetre, two _librae_ of stones which when thrown into a hot furnace

are easily liquefied by fire of the third order, half a _libra_ each of

verdigris[4], of _stibium_, of iron scales and filings, and of

asbestos[5], and one and one-sixth _librae_ of spring water.

All the vitriol from which the _aqua_ is usually made is first reduced

to powder in the following way. It is thrown into an earthen crucible

lined on the inside with litharge, and heated until it melts; then it is

stirred with a copper wire, and after it has cooled it is pounded to

powder. In the same manner saltpetre melted by the fire is pounded to

powder when it has cooled. Some indeed place alum upon an iron plate,

roast it, and make it into powder.

Although all these _aquae_ cleanse gold concentrates or dust from

impurities, yet there are certain compositions which possess singular

power. The first of these consists of one _libra_ of verdigris and

three-quarters of a _libra_ of vitriol. For each _libra_ there is poured

over it one-sixth of a _libra_ of spring or river water, as to which,

since this pertains to all these compounds, it is sufficient to have

mentioned once for all. The second composition is made from one _libra_

of each of the following, artificial orpiment, vitriol, lime, alum, ash

which the dyers of wool use, one quarter of a _libra_ of verdigris, and

one and a half _unciae_ of _stibium_. The third consists of three

_librae_ of vitriol, one of saltpetre, half a _libra_ of asbestos, and

half a _libra_ of baked bricks. The fourth consists of one _libra_ of

saltpetre, one _libra_ of alum, and half a _libra_ of sal-ammoniac.[6]

[Illustration 442 (Nitric Acid Making): A--Furnace. B--Its round hole.

C--Air-holes. D--Mouth of the furnace. E--Draught opening under it.

F--Earthenware crucible. G--Ampulla. H--Operculum. I--Its spout.

K--Other ampulla. L--Basket in which this is usually placed lest it be

broken.]

The furnace in which _aqua valens_ is made[7] is built of bricks,

rectangular, two feet long and wide, and as many feet high and a half

besides. It is covered with iron plates supported with iron rods; these

plates are smeared on the top with lute, and they have in the centre a

round hole, large enough to hold the earthen vessel in which the glass

ampulla is placed, and on each side of the centre hole are two small

round air-holes. The lower part of the furnace, in order to hold the

burning charcoal, has iron plates at the height of a palm, likewise

supported by iron rods. In the middle of the front there is the mouth,

made for the purpose of putting the fire into the furnace; this mouth is

half a foot high and wide, and rounded at the top, and under it is the

draught opening. Into the earthen vessel set over the hole is placed

clean sand a digit deep, and in it the glass ampulla is set as deeply as

it is smeared with lute. The lower quarter is smeared eight or ten times

with nearly liquid lute, each time to the thickness of a blade, and each

time it is dried again, until it has become as thick as the thumb; this

kind of lute is well beaten with an iron rod, and is thoroughly mixed

with hair or cotton thread, or with wool and salt, that it should not

crackle. The many things of which the compounds are made must not fill

the ampulla completely, lest when boiling they rise into the operculum.

The operculum is likewise made of glass, and is closely joined to the

ampulla with linen, cemented with wheat flour and white of egg moistened

with water, and then lute free from salt is spread over that part of it.

In a similar way the spout of the operculum is joined by linen covered

with lute to another glass ampulla which receives the distilled _aqua_.

A kind of thin iron nail or small wooden peg, a little thicker than a

needle, is fixed in this joint, in order that when air seems necessary

to the artificer distilling by this process he can pull it out; this is

necessary when too much of the vapour has been driven into the upper

part. The four air-holes which, as I have said, are on the top of the

furnace beside the large hole on which the ampulla is placed, are

likewise covered with lute.

All this preparation having been accomplished in order, and the

ingredients placed in the ampulla, they are gradually heated over

burning charcoal until they begin to exhale vapour and the ampulla is

seen to trickle with moisture. But when this, on account of the rising

of the vapour, turns red, and the _aqua_ distils through the spout of

the operculum, then one must work with the utmost care, lest the drops

should fall at a quicker rate than one for every five movements of the

clock or the striking of its bell, and not slower than one for every

ten; for if it falls faster the glasses will be broken, and if it drops

more slowly the work begun cannot be completed within the definite time,

that is within the space of twenty-four hours. To prevent the first

accident, part of the coals are extracted by means of an iron implement

similar to pincers; and in order to prevent the second happening, small

dry pieces of oak are placed upon the coals, and the substances in the

ampulla are heated with a sharper fire, and the air-holes on the furnace

are re-opened if need arise. As soon as the drops are being distilled,

the glass ampulla which receives them is covered with a piece of linen

moistened with water, in order that the powerful vapour which arises

may be repelled. When the ingredients have been heated and the ampulla

in which they were placed is whitened with moisture, it is heated by a

fiercer fire until all the drops have been distilled[8]. After the

furnace has cooled, the _aqua_ is filtered and poured into a small glass

ampulla, and into the same is put half a _drachma_ of silver[9], which

when dissolved makes the turbid _aqua_ clear. This is poured into the

ampulla containing all the rest of the _aqua_, and as soon as the lees

have sunk to the bottom the _aqua_ is poured off, removed, and reserved

for use.

Gold is parted from silver by the following method[10]. The alloy, with

lead added to it, is first heated in a cupel until all the lead is

exhaled, and eight ounces of the alloy contain only five _drachmae_ of

copper or at most six, for if there is more copper in it, the silver

separated from the gold soon unites with it again. Such molten silver

containing gold is formed into granules, being stirred by means of a rod

split at the lower end, or else is poured into an iron mould, and when

cooled is made into thin leaves. As the process of making granules from

argentiferous gold demands greater care and diligence than making them

from any other metals, I will now explain the method briefly. The alloy

is first placed in a crucible, which is then covered with a lid and

placed in another earthen crucible containing a few ashes. Then they are

placed in the furnace, and after they are surrounded by charcoal, the

fire is blown by the blast of a bellows, and lest the charcoal fall away

it is surrounded by stones or bricks. Soon afterward charcoal is thrown

over the upper crucible and covered with live coals; these again are

covered with charcoal, so that the crucible is surrounded and covered on

all sides with it. It is necessary to heat the crucibles with charcoal

for the space of half an hour or a little longer, and to provide that

there is no deficiency of charcoal, lest the alloy become chilled; after

this the air is blown in through the nozzle of the bellows, that the

gold may begin to melt. Soon afterward it is turned round, and a test is

quickly taken to see whether it be melted, and if it is melted, fluxes

are thrown into it; it is advisable to cover up the crucible again

closely that the contents may not be exhaled. The contents are heated

together for as long as it would take to walk fifteen paces, and then

the crucible is seized with tongs and the gold is emptied into an oblong

vessel containing very cold water, by pouring it slowly from a height so

that the granules will not be too big; in proportion as they are

lighter, more fine and more irregular, the better they are, therefore

the water is frequently stirred with a rod split into four parts from

the lower end to the middle.

The leaves are cut into small pieces, and they or the silver granules

are put into a glass ampulla, and the _aqua_ is poured over them to a

height of a digit above the silver. The ampulla is covered with a

bladder or with waxed linen, lest the contents exhale. Then it is heated

until the silver is dissolved, the indication of which is the bubbling

of the _aqua_. The gold remains in the bottom, of a blackish colour, and

the silver mixed with the _aqua_ floats above. Some pour the latter into

a copper bowl and pour into it cold water, which immediately congeals

the silver; this they take out and dry, having poured off the

_aqua_[11]. They heat the dried silver in an earthenware crucible until

it melts, and when it is melted they pour it into an iron mould.

The gold which remains in the ampulla they wash with warm water, filter,

dry, and heat in a crucible with a little _chrysocolla_ which is called

borax, and when it is melted they likewise pour it into an iron mould.

Some workers, into an ampulla which contains gold and silver and the

_aqua_ which separates them, pour two or three times as much of this

_aqua valens_ warmed, and into the same ampulla or into a dish into

which all is poured, throw fine leaves of black lead and copper; by this

means the gold adheres to the lead and the silver to the copper, and

separately the lead from the gold, and separately the copper from the

silver, are parted in a cupel. But no method is approved by us which

loses the _aqua_ used to part gold from silver, for it might be used

again[12].

[Illustration 446 (Parting precious metals with nitric acid):

A--Ampullae arranged in the vessels. B--An ampulla standing upright

between iron rods. C--Ampullae placed in the sand which is contained in

a box, the spouts of which reach from the opercula into ampullae placed

under them. D--Ampullae likewise placed in sand which is contained in a

box, of which the spouts from the opercula extend crosswise into

ampullae placed under them. E--Other ampullae receiving the distilled

_aqua_ and likewise arranged in sand contained in the lower boxes.

F--Iron tripod, in which the ampulla is usually placed when there are

not many particles of gold to be parted from the silver. G--Vessel.]