Copper (from =cuprum=, a corruption of =cuprium=, from the island of
Cyprus, whence it was formerly brought) was known at a very remote
period; and in the early ages of the world, before iron was extensively
in use, was the chief ingredient in domestic utensils and instruments of
war. It is abundant; and is found both native and in many ores, the most
important of which are the varieties of _pyrites_, which are sulphurets
of copper and iron. The genus copper includes some thirteen species, and
each of these contains several varieties.
The purest copper obtained in Europe, is the produce of the mines of the
Swedish province of Dalecarlia. The following is a brief description of
the principal of these immense and gloomy caverns, all of which boast a
high antiquity.
The traveler’s curiosity is first attracted by the hydraulic machines
which convey the water to the different quarters, and the power of which
is such, that one of the wheels has a diameter of not less than
forty-four feet. Another wheel, of proportionate magnitude, is employed
to raise the ore from the mine to the surface of the earth, and is
admirably constructed. Regular circles are placed on each side, and
round these the chain rises, taking a larger or smaller circumference,
in proportion to the necessary circle to be made, so as to
counterbalance the weight, and consequently the increased motion of the
bucket.
Exteriorly, a vast chasm of a tremendous depth presents itself to the
view. This being the part of the mine which was first opened, either
through the ignorance or neglect of those who had then the management of
the works, the excavations so weakened the foundations of the hill, that
the whole fell in, leaving a most chaotic scene of precipitated rocks,
and a gaping gulf resembling the mouth of a volcano. Great care has been
since taken that no such disaster should again occur. Plans and sections
are drawn of all the galleries, &c.; and where the prosecution of the
works in the same direction might be dangerous, orders are issued for
the miners to stop, and an iron crown is fixed on the spot, as a
prohibition ever to proceed further. The workmen then explore in a
different direction, while every subterraneous excavation is nicely
watched.
The traveler passes into the great chasm by a range of wooden steps,
which cross, in a variety of directions, the rough masses of fallen
rocks, of gravel, and of the ancient machinery. Ere he reaches the
entrance of the cavern, he has to descend nearly two hundred feet, and
this being accomplished, proceeds horizontally to a considerable
distance within. He now loses the pure air of day, and gradually
breathes an oppressive vapor, which rolls toward him, in volumes, from
the mouths of a hundred caves leading into the main passage. He now
feels as if he were inhaling the atmosphere of Tartarus. The Swedish
iron mines which have been described, are mere purgatories when compared
with this satanic dwelling. The descent is performed entirely by steps
laid in the winding rock; and, in following the subterraneous declivity,
the traveler reaches the tremendous depths of these truly Stygian
dominions.
The pestilential vapors which environ him with increasing clouds, and
the style of the entrance, remind him of Virgil’s description of the
descent of Eneas to the infernal regions. Here are to be seen the same
caverned portico, the rocky, rough descent, and the steaming sulphur,
with all the deadly stenches of Avernus. The wretched inmates of this
gloomy cavern, appear to him like so many specters, as poetic fiction
has described them: and he is induced by the length of the way, joined
to the excessive heat and its suffocating quality, to fancy that he will
be made to pay dearly for his curiosity. In one part the steam is so
excessively hot, as to scorch at the distance of twelve paces, at the
same time that the sulphureous smell is intolerable. Near this spot a
volcanic fire broke out some years ago, in consequence of which strong
walls were constructed, as barriers to its power, and several contiguous
passages, which, had it spread, would have proved dangerous to the mine,
closed up.
The visitor has now to traverse many long and winding galleries, as well
as large vaulted caverns, where the workmen are dispersed on all sides,
employed in hewing vast masses of the rock, and preparing other parts
for explosion. Others wheel the brazen ore toward the black abyss, where
the suspended buckets hang ready to draw it upward. From the effect of
such violent exercise, combined with the heat, they are obliged to work
almost naked. Their groups, occupations, and primitive appearance,
scantily lighted by the trembling rays of torches, form a curious and
interesting scene.
The depth of the mine being at least twelve hundred feet, a full hour is
required to reach to the bottom. The mass of copper lies in the form of
an inverted cone. Five hundred men are employed daily; but females are
not admitted, on account of the deleterious quality of the vapors. This
mine was anciently a state prison, in which criminals, slaves and
prisoners of war toiled out their wretched existence. Near the bottom is
a rocky saloon, furnished with benches. It is called the Hall of the
Senate, on account of its having been the resting-place of several
Swedish kings, who came, attended by the senators, to examine the works,
and here took refreshments. It was in this mine that the immortal
Gustavus Vasa, disguised as a peasant, labored for his bread, during a
long concealment, after having been robbed by his guide; and his first
adherents in the struggle which placed him on the throne, were from the
miners and peasants of Dalecarlia.
In the year 1751, a very rich copper mine was wrought in the county of
Wicklow, Ireland. From this mine ran a stream of blue-colored water, of
so deleterious a nature as to destroy all the fish in the river Arklow,
into which it flowed. One of the workmen, having left an iron shovel in
this stream, found it some days after incrusted with copper. This led
one of the proprietors of the mine to institute a set of experiments,
from which he concluded that the blue water contained an acid holding
copper in solution; that iron had a stronger affinity for the acid than
copper; and that the consequence of this affinity was the precipitation
of the copper, and the solution of the iron, when pieces of that metal
were thrown into the blue water. These ideas induced the miners to dig
several pits for the reception of this water, and to put bars of iron
into them. The result was, that they obtained an abundance of copper,
much purer and more valuable than that which they had procured from the
ore itself by smelting.
On the island of Anglesea, near Dulas bay, on the north coast, is Parys
mountain, which contains the most considerable quantity of copper ore
perhaps ever known. The external aspect of the hill is extremely rude,
and it is surrounded by enormous rocks of coarse white quartz. The ore
is lodged in a basin, or hollow, and has on one side a small lake, over
the waves of which, as over those of Avernus, fatal to the feathered
tribe, it is said that birds are never known to pass. The effect of the
mineral operations has been, that the whole of this tract has assumed a
wild and savage appearance. Suffocating fumes of the burning heaps of
copper arise in all parts, and extend their baneful influence for miles
around. That the ore was worked in a very remote period, appears by
vestiges of the ancient operations, which were carried on by trenching,
and by heating the rocks intensely, when water was suddenly poured on
them, so as to cause them to crack or scale. In the year 1768, after a
long search, which was so little profitable that it was on the eve of
being abandoned, a large body of copper ore was found; and this has ever
since been worked to great advantage, still promising a vast supply. The
water lodged in the bottom of the bed of ore, being strongly impregnated
with the metal, is drawn up and distributed in pits, where the same
process is employed as in the Wicklow mine. The copper thus procured
differs little from native copper, and is very highly prized.
In the Parys mine, eight tuns of gunpowder are annually expended in
blasting the rock. Nature has here been profuse in bestowing her mineral
favors; for, above the copper ore, and not more than two feet beneath
the soil, is a bed of yellowish greasy clay, from three to twelve feet
in thickness, containing lead ore, from a tun of which metal, upward of
fifty ounces of silver are generally obtained.
[Illustration: COPPER MINE IN CORNWALL.]
The copper mines of Cornwall, a view of one of which is given in the
cut, are very numerous, and several of them large and very rich in ore.
It is remarkable that in various parts of this country the earth has
produced such an exuberance of this metal, as to afford it in large
massy lumps of malleable copper, several pieces of which are shown in
very curious vegetable forms. The particular ore named _mundic_, found
in the tin mines, was for many ages considered of no other use but to
nourish that metal while in the mine. In the reign of Queen Elizabeth, a
laudable curiosity tempted several private individuals to examine into
its nature; but the design miscarried, and the mundic was thrown, as
useless, into the old pits in which the rubbish was collected. However,
about a century ago, this purpose was effected by degrees; and the
copper extracted from the ore now produces, on an average, upward of
twelve thousand tuns, valued at between four and five millions of
dollars, annually, equaling in goodness the best Swedish copper, while
the ore itself yields a proportionate quantity of =lapis calaminaris=,
for the making of brass.
At Ecton hill, near the river Dove, in Derbyshire, a valuable copper
mine was discovered some years ago, and has since been worked to great
advantage. In its position, situation and inclination, it differs from
any mine yet discovered in Europe, Asia, Africa or America; the
wonderful mass of copper ore not running in regular veins or courses,
but sinking perpendicularly down, widening and swelling out at the
bottom in the form of a bell. The works are four hundred and fifty feet
beneath the river Dove, it being the deepest mine in Great Britain. On
the opposite side of Ecton hill is a valuable lead mine, the veins of
which approach very nearly to the copper mine.
Copper is converted into brass by the agency of calamine, an oxyd of
zinc. It occurs frequently in beds, and in some places exists in great
abundance. The Mendip hills, in Somersetshire, were once celebrated for
their mines of calamine, which are now in a great measure exhausted. It
is dug out of the earth, and being broken into small pieces, is exposed
to the action of a current of water, which washes away the light earthy
matter, and leaves the calamine. The whole is then thrown into deep
wooden vessels filled with water, and agitated for a considerable time.
The galena sinks to the bottom, the calamine is deposited in the center,
and the earthy matter lies on the surface. The calamine, thus separated
from its impurities, is ground to powder, and becomes fit for use.
Hungary abounds in valuable ores and minerals, and is most celebrated
for its vast copper works, at a town called Herrengrund, built on the
summit of a mountain, and exclusively inhabited by miners. Here the
process, noticed above, of apparently converting iron into copper, is
pursued with great success, several hundred weight of iron being thus
transmuted every year. The vitriol, with which the blue water is
strongly impregnated, can not be strictly said to convert the iron into
copper, but insinuates into it the copper particles with which it is
saturated; and this seeming transmutation requires a fortnight or three
weeks only: but if the iron be suffered to lie too long in this
vitriolic solution, it becomes at length reduced to powder.
In Japan, copper is the most common of all the metals, and is considered
as the finest and most malleable anywhere to be found. Much of this
copper is not only of the purest quality, but is blended with a
considerable proportion of gold, which the Japanese separate and refine.
The whole is brought to Saccin, one of the five principal cities of
Japan; and it is there purified, and cast into small cylinders, about a
span and a half in length, and a finger’s breadth in thickness. Brass is
there very scarce, and much dearer than copper, the calamine employed in
making it being imported from Tonquin in flat cakes, and sold at a very
high price.
In addition to the copper mines thus described, copper has, within a few
years, been found in the richest abundance in the vicinity of Lake
Superior. The existence of copper there, was, indeed, known as early as
1636; and the trace of these early discoveries was never entirely lost.
But the first scientific researches were made in 1842, by Dr. Douglas
Houghton, who was acting as geological surveyor for the state of
Michigan. According to his report, native copper exists in two or three
different deposits about Lake Superior, where it is found in the richest
abundance, both in veins and in large masses in the native state. Dr.
Jackson also states, that he has seen one of these masses, twenty feet
long, nine feet wide, and from four to six inches in thickness, and
weighing about twenty tuns. He adds, that in a single year, thirty-three
men, of whom only twenty were properly miners, had taken out forty-three
tuns of ore, yielding thirty tuns of pure copper. Among the masses of
copper obtained from these mines as early as 1848, were four, the
weights of which, respectively, were seven thousand and eighteen, seven
thousand four hundred and eighty-four, seven thousand six hundred and
seventy-eight, and fourteen thousand pounds. Since that date new
openings have been made; new mining companies formed, and the products
of the mines very greatly increased: and it may yet be, that these mines
will prove some of the richest and most valuable of the world.