pursue their operations at all times, even during the winter months,
whenever the weather was not particularly unfavourable. But as soon as
the excavation was carried, to some extent, in a lateral direction, the
hope was disappointed, for the sea water penetrated through the fissures
of the rock, and, in proportion as the workings became enlarged, the
labour of raising the ore to the mouth of the shaft increased. To add to
all this, it was found impossible to prevent the water from forcing its
way through the shaft during the winter months, or, on account of the
swell and surf, to remove the tin-stone from the rock to the beach
opposite. Hence the whole winter was a period of inaction, and the
regular working of the mine could not be resumed before April.
Nevertheless, the short interval which was still allowed for labour
below ground was sufficient to reward the bold and persevering
projector.
The close of this wonderful mine, from which many thousand pounds worth
of tin was raised, was as romantic as its commencement. An American
vessel broke from its anchorage in Gwavus Lake, and, striking against
the stage, demolished the machinery, and thus put an end to an adventure
which, both in ingenuity and success, was in all probability unequalled
in any country.
This wonderful mine was worked again a few years since; but, although a
very large sum of money was expended, and it had all the advantage of
improved machinery, yet it failed to be a profitable adventure, and was
eventually abandoned.
The Carclaze tin-mine, near the town of St. Austell, though unimportant
with regard to its produce, deserves to be noticed for its picturesque
appearance and the manner in which it is worked. It consists of a large
open excavation, of a mile in circuit and from twenty to thirty fathoms
in depth, looking more like a vast natural crater than a hollow made by
human hands; and for hours the visitor might traverse the dreary and
barren hilly common in which it is situated without suspecting that a
mine is close at hand. No engine-house and chimney towering aloft
announces it from afar; the whole business is confined to the interior
of the punch-bowl hollow. Every detail of the works is here exposed to
view, and it would seem as if a complete mine had been turned inside out
for the benefit of timid travellers, who would wish to see the various
operations of mining without the risk of a descent below the surface.
The walls of this vast hollow or crater are almost perpendicular, and
the view from the ridge of the precipice, into which but few footpaths
descend, is rendered interesting by the fantastic shape of the rocks,
worn or hewn into a thousand grotesque forms by the action of the waters
or the pickaxe of the miner; by the enormous number of holes and hollows
resulting from ancient excavations; by the white colour of the granite,
veined with the darker metalliferous streaks; by the water-wheels at the
bottom, which, worked by streams from the neighbouring commons, propel
the machinery for crushing the stones, loosened by the water as it flows
down the sides of the cavity; and by the men, women, and children,
scattered over the works. The ore is obtained without much difficulty,
and is easily separated from the friable and decomposed granite, in
which it is embedded, by repeated washings in the streams that are made
to flow out at the bottom of the mine through a channel or tunnel, and
which carry away the soft _growan_ or granite by their rapid current,
while the heavier metalliferous substances are precipitated.
As the ores are very poor, not even containing one per cent. of tin,
Carclaze, which has been already worked for many centuries, would long
since have been abandoned but for the abundance of the ores and the
comparatively small expense of their extraction.
The dressing of the tin ores, or the process by which they are separated
as far as possible from the earthy impurities which are mixed up with
them, and are generally much lighter, begins with cleaning and sorting,
and then goes on to washing and stamping, and finally to calcination in
the burning-house and to smelting.
The tin ores of Cornwall and Devonshire are all reduced within the
counties where they are mined, as the law prohibits their exportation—a
most absurd and antiquated regulation, which, however, in this case is
not injurious to private interests, as the vessels which bring the fuel
from Wales for the smelting furnaces return to Swansea and Neath laden
with copper ores. The smelting works, not exceeding seven or eight in
number, belong generally not to the proprietors of the mines, but to
other parties, who purchase the ore from the proprietors.
The smelting is effected by two different methods, which may be briefly
described by stating that, by the first and most common, the ore, mixed
with culm, is exposed to heat upon the hearth of a reverberating
furnace, in which pit coal is used as fuel; while by the second method,
which is applied merely to stream-tin, and which is followed in order to
obtain tin of the finest quality, the ore is fused in a blast-furnace
called a blowing-house, in which wood fuel or charcoal is used. The
melted tin runs off from the furnace into an open basin, whence it flows
into a large vessel, where it is allowed to settle. The scoriæ are
skimmed off, and the subsequent operations consist of refining by
allowing the mass of the metal to rest, then submitting the upper and
pure portion to the refining basin, and remelting the lower part. In
order to convert the blocks into _grain-tin_, they are heated until they
become brittle, and made to fall from a considerable height in a semi-
fluid state, thus producing an agglomerated mass of elongated grains.
The number of persons that find occupation in and about the Cornish and
Devonian tin mines may amount to about 20,000. The wages are, on an
average, much inferior to those of the pitmen and pitlads in the
northern coal-fields; but, on the other hand, the Cornish miner is
exempt from many evils to which the northern miners are subject. He has
not to fear the fatal fire-damp, and can sit at ease and hear or read of
explosions that have destroyed hundreds in a few minutes.
His intellectual superiority to the agricultural labourer may be at once
inferred from the nature of his pursuits. The latter plods on through
life like a mere human machine, and, as he is never thrown on his own
resources in the progress of his monotonous occupations, his stock of
ideas remains scanty and confined. But the Cornish miner is the reverse
of all this. He is engaged mostly in work requiring the exercise of the
mind. He is constantly taking a new ‘pitch’[55] in a new situation,
where his judgment is called into action. His wages are not the stinted
recompense of half-emancipated serfdom; but they arise from contract,
and depend upon some degree of skill and knowledge. In fact the chances
of the lode keep expectation constantly awake, and thus:—
‘Hope reigns triumphant in the _miner’s_ breast,
Who never is, but always to be blest.’
Footnote 55:
The lodes in the Cornish tin and copper mines are divided by shafts
and galleries into rectangular compartments, called ‘pitches.’ These
are open to the inspection of all the labouring miners in the county,
and, by an admirable system, each ‘pitch’ is let by public
competition, for two months, to two or four or more miners, who may
work it as they choose. These men agree to break the ores, wheel them,
raise them to the surface, and bring them (if desired) into a fit
condition for the market. The ores so raised are sold every week, and
the miner immediately receives his _tribute_, or percentage for which
he agreed to work. The sinking of shafts and the driving of levels is
paid by tut-work, or task work, at so much per fathom.
If he is at all imaginative, golden dreams enliven the darkness of his
underground labour. He is in fact a kind of subterranean stock-jobber,
and ‘settling day’ is as anxious a time for the humble tributer at the
Land’s End as for the bold speculator of the Stock Exchange.
When not exhausted after his hard day’s labour, the miner frequently
cultivates a small patch of land. Many have tolerable gardens, and some
are able to perform their own carpentry, while, if near the coast,
others are expert fishermen.
CHAPTER XXVIII.
IRON.
Iron the most valuable of Metals—Its wide Diffusion over the Earth—
Meteoric Iron—Iron very anciently known—Extension of its Uses in
Modern Times—British Iron Production—Causes of its Rise—Hot Blast—
Puddling—Coal-smelting—The Cleveland District—Rapid Rise of
Middlesborough—British Iron Ores—Production of Foreign Countries—The
Magnetic Mountain in Russia—The Eisenerz Mountain in Styria—Dannemora—
Elba—The United States—The Pilot Knob—The Cerro del Mercado.
As an instrument of civilisation iron is the most valuable and the most
indispensable of all mineral substances. Even coal is of inferior
importance to the welfare of mankind, for iron may be obtained without
its aid, while coal could not possibly be extracted from the bowels of
the earth without the assistance of iron. Hard and malleable, tenacious
and ductile, endowed with the singular property of welding, which is
found in no other metal except platinum, and acquiring new qualities by
its conversion into steel, it accommodates itself to all our wants and
even to our caprices, so that no other metal has such various and
extensive uses. It clothes our war ships with a case of impenetrable
armour, and sets the finest watch in motion; it provides the sempstress
with her needle, and guides the mariner over the ocean; it furnishes the
husbandman with his ploughshare, and the soldier with his sword; it
concentrates in the steam-engine the sinews of a thousand horses, and
mocks on the railroad the fleetness of the swiftest courser. It is, in
one word, the embodiment of power, the chief agent of all social
progress.
‘Were the use of iron lost among us,’ says the illustrious Locke, ‘we
should, in a few ages, be unavoidably reduced to the wants and ignorance
of the ancient savage Americans;’ nor will this view be deemed
extravagant if we reflect that, but for iron, man would be _virtually
without_ tools, since it is almost the only metal capable of taking a
sharp edge and keeping it.
The bounty of the Creator, which bestowed on man this inestimable gift,
has also provided for its wider diffusion over the earth than is the
case with any other of the useful metals. Few mineral substances or
stones are without an admixture of it. Sands, clays, the waters of
rivers or springs, are scarcely ever perfectly free from iron, while
animal and vegetable substances likewise afford it in the residues which
they leave after incineration. Its mines may truly be said to be
inexhaustible; in some its ores occur in compact masses of extraordinary
magnitude, in others they spread in vast strata or extend in veins of a
prodigious length.
Yet, in spite of its wide diffusion, the extraction of iron from its
ores generally requires so much metallurgic skill that its use would
probably have remained undiscovered by the ancients if Providence had
not in a wonderful manner revealed, as it were, its existence to
mankind.
All iron of a _terrestrial_ origin is combined with other substances,
which conceal its true nature from the uninitiated eye, and from which
it is with difficulty separated; but here and there, scattered over the
surface of the earth, are found solitary masses of metallic iron, which,
having fallen from the skies, may truly be called erratic boulders from
another world. The idea of their having dropped from the clouds was long
ridiculed by the learned; but their fall has been so often observed, and
so circumstantially recorded in the annals of almost every age, that
scepticism has been obliged to yield to the weight of accumulated
evidence, and science no longer doubts their meteoric origin. Nothing
can be more interesting than these mysterious heralds from the distant
fields of ether, which, after wandering through space for countless
ages, have at length been brought within the sphere of attraction of our
planet, and, alighting on its surface, afford us tangible proofs that
many of the substances of which our earth is composed—iron, nickel,
silex, &c., &c.—exist beyond its limits, and that most probably our
whole solar system is constructed of the same materials as our globe.
But meteoric iron—which sometimes occurs in enormous masses[56]—is more
than a mere object of curiosity, for it has had a most important
influence on the progress of the human race. On such a mass undoubtedly
the _first smith_ exercised his skill, and it was this which first made
mankind acquainted with a metal more valuable than copper or gold.
Footnote 56:
The weight of the mass found at Otumpa, in the Gran Chaco Gualamba, in
South America, by Don Rubin de Celis (1783) was estimated at about
fifteen tons. A piece from this mass, weighing 1,400 pounds, is now in
the British Museum.
As we see from the example of the Esquimaux, whom Captain Ross (1819)
found in possession of knives and harpoons which they had made from
masses of meteoric iron, the discovery was probably made at a very
remote period, while man was still in the savage state; but iron having
once become known, the desire to obtain it in larger quantities from
other sources naturally grew with the progress of civilisation, and
gradually led to the knowledge of its ores and of the art of utilising
them. Thus there can hardly be a doubt that iron-smelting was practised
long before historic times. In India and China the origin of its use
loses itself in the remotest antiquity; and the imposing monuments of
ancient Egypt, many of which are at least five thousand years old, could
not possibly have been erected without the aid of iron. In the Book of
Deuteronomy (iv. 20) the land of Egypt is compared to an iron-furnace—a
figurative expression which shows that even at that early period iron-
smelting must have been a well-known branch of industry.
The iron weapons found in the lacustrine dwellings of Switzerland
likewise point to a very ancient use of iron in Central Europe, no less
than the fact mentioned by Cæsar, that during the siege of Avaricum
(Bourges) the works erected by the Romans for taking the town were
repeatedly destroyed by the subterranean galleries of the besieged, who,
as the conqueror relates, were accustomed to such underground labour
from their habitually working in iron-mines, an industry which, to judge
from this passage, must even then have been of ancient date in Gaul.
For many ages the uses of iron remained chiefly confined to the
instruments of agriculture and of war—to the ploughshare and the sword.
With the progress of civilisation its employment extended to many
purposes unknown before; and in our times the construction of ships and
buildings, of railroads and bridges, absorbs quantities which would have
appeared incredible almost within the memory of living man. Hence the
manufacture of iron has made more rapid progress since the beginning of
the present century than in any former period of the world’s history,
and even the present immense production scarcely keeps pace with a
demand to which it is not easy to assign a limit.
Among the iron-_producing_ countries of the globe Great Britain occupies
by far the first rank, and there is every reason to believe that it will
long continue to maintain it. The British ores, indeed, are generally
poor, as clay, silica, phosphorus, and a variety of impurities which are
with difficulty separated from the metal, enter into the composition of
those which supply the greatest part of our iron; but this deficiency is
more than counterbalanced by many advantages. Most of the British iron
mines are situated in those districts where coal is cheapest, the ore
being often even raised from the same pit as that from which the coal is
extracted. Limestone, the necessary flux, is at hand, while fire-clay,
no unimportant article in the building of the furnaces, on whose long-
continued working so much depends, is found in the same ground as the
ore itself. The largest and most complete manufactories have long been
established in the most convenient places. With an almost unlimited
amount of capital, the most perfect and the cheapest communication by
water is open to all parts of the world; and the further processes which
the metal has to undergo are performed at once on the spot in the best
manner and at the smallest possible expense. No other land can boast of
equal or greater facilities for the production of an unlimited quantity
of cheap iron, so that, even with the assistance of heavy protective
duties, most of the iron-producing countries of Europe find it difficult
to compete in their own markets with the produce of Great Britain.
The art of making iron in this country is of very ancient though of
unascertained date. It was probably found by the Romans in a far
advanced state. It certainly was carried on by them subsequently to a
great extent—a fact proved by the immense beds of iron cinders
discovered in the Forest of Dean; nor has it ever been discontinued by
the other races who in succession have held sway in the island. But,
though of such ancient origin, and enjoying so many natural advantages,
our iron manufacture remained confined within very narrow limits so long
as the ore was exclusively smelted by means of charcoal made from wood.
The manufacture was even for some time partially prohibited in England,
the consumption of wood-charcoal in the process of smelting being so
great as to create apprehensions that, if care were not taken of the
remaining forests, enough timber would not be left to supply the wants
of the navy. It seems almost incredible in our days that Acts were
passed in the reigns of Elizabeth and James forbidding the felling of
timber for the smelting of iron, except in certain districts of Kent,
Sussex, and Surrey, then the principal seats of the manufacture, and
even there the erection of new works was expressly forbidden.
Attention was then directed to the smelting of ironstone by means of pit
coal. Amongst others, Lord Dudley gallantly struggled to establish a
manufactory in the neighbourhood of Stourbridge, and partially
succeeded; but what with riots among the ironworkers, who destroyed his
works, and the wars of the Great Rebellion, which ruined his fortune, he
reaped no advantage from his enterprise. Nothing contributed to arrest
the decline in this branch of trade, and towards the middle of last
century the number of furnaces, which in the reign of James I. had
amounted to 300, fell off to 59, the total make of which amounted to not
more than 17,350 tons, being an average of 294 tons per annum for each
furnace, a quantity very little exceeding that sometimes made in a
single week in some of the huge furnaces in Wales in the present day.
The partial use of pit coal in the process of smelting was revived in
Coalbrookdale, in Shropshire, about 1713. The chief difficulty was to
keep the coal in a state of combustion sufficiently intense for the
purpose of smelting the ore; the hand-worked bellows, or the more
powerful water movement, which produced blast enough for charcoal,
having comparatively little effect upon coal.
This obstacle was finally overcome through the perseverance and
enterprise of Dr. John Roebuck (a physician in Birmingham, and
grandfather of the late distinguished member for Sheffield), who,
seeking for more economical methods of smelting iron ore than those then
in use, founded in 1759 the now celebrated Carron Works, where John
Smeaton, the illustrious architect of the Eddystone lighthouse, first
introduced (1760) a new contrivance for throwing a powerful and constant
blast into the furnace. By means of a forcing pump, a large column of
air, of triple or quadruple density to that which had been previously
obtained, could now be poured into the furnace; and effects equivalent
to this great improvement followed. The same smelting oven that formerly
yielded ten or twelve tons weekly now sometimes produced forty tons in
the same period; and such was the impulse given to the trade by this
unexpected success of a powerful blast with pit coal that in 1788 the
manufacture of pig-iron in England, Wales, and Scotland amounted to
68,300 tons, being an increase of 50,950 tons on the quantity
manufactured previous to the introduction of pit coal.
In 1782 Mr. Cort, after many years of experiments, discovered the means
of converting cast or pig-iron into malleable iron by a process which
was at once sure, rapid, and economical. The iron is remelted in a
puddling furnace, as it is called, which is heated with raw coal, and
there, by a series of operations, the object of which is to give the
iron malleability and toughness by expelling the carbon, it is
manipulated until it acquires the consistency of a solid white-hot ball.
In this shape it is subjected to the action of an enormous hammer, by
which the coarser parts are beaten from it, and it is formed into the
shape of thick short bars, called blooms or slabs. While still red-hot
it is passed through a series of grooved rollers, till it is drawn out
into a long bar, the exact dimensions of which are regulated by the
requirements of the manufacture for which it is destined. The bars thus
made are technically called puddled bars, and considered as _half-
manufactured_ iron. To refine them into _merchant_-iron, they are again
submitted to the action of fire, and, when hot enough, are welded
together and formed into the various denominations of bars, rods, hoops,
sheets, or plates. Mr. Cort’s discovery, though of immense importance,
would yet have proved of comparatively small value without the aid of
the double-power steam-engine, which was about the same time invented by
James Watt, and supplied the power which was needed to give our iron-
works their full development.
Hitherto the ‘top measures’ only of the mineral had been worked, and
generally on ‘the rise of the mine,’ where the water would not lie, or
those strata favourably situated on the side of a hill where levels
could be driven in and the water released. Water was the great enemy in
the pits, and even in shallow workings it often accumulated faster than
a gin turned by horse-power could bring it to the surface. By the new
agency of steam the deepest pits were drained, and materials were drawn
up from the bowels of the earth in a quantity and with a rapidity and
security hitherto unknown. By the same means that prodigious blast was
obtained for the furnaces to which all subsequent improvements of the
manufacture owe their origin. Instead of the rude machinery of
waterwheels and bellows, huge engines of enormous power forced an
immense volume of air through several small _tuyeres_ or tubes so
disposed at the lower part of the furnaces that in each portion of the
ignited mass an equally diffused blast might raise an equal intensity of
heat. Furnaces of greater height and much larger capacity than any
hitherto known were erected, and in its general aspect the iron
manufacture assumed very much the appearance which it maintains at the
present day.
[Illustration:
BLAST FURNACE.
_a._ Tuyeres.
]
Most readers are aware[57] that the flaming towers which give such an
unearthly effect at night to what is called the Black Country, round
Wolverhampton, are iron furnaces, and that the projecting circular
galleries which surround their tops are contrived for pouring down their
capacious throats, by apertures placed at equal distances, an equable
and regular supply of the materials with which they are fed. Besides the
iron-stone and the fuel, there is needed a third substance, which is
called ‘a flux,’ because it forms a fusible compound with the earthy
matter of the mineral. When we are acquainted with the foreign matter in
combination with the ore, chemistry tells us what substance we ought to
add for the purpose of eliminating the metal. Among the wonderful
provisions of nature for the convenience of man, none is more remarkable
than that by which many substances are fusible in conjunction at a
temperature which either could resist separately. The British ores are
for the most part argillaceous, that is to say, they are combined with
what, in its general character and appearance, resembles clay. To all
such limestone in due proportion must be added; but if the earthy matter
consists of lime, clay is the proper flux. In either case the foreign
matter and the flux are fused into one substance. The liberated iron
sinks downwards, and having now itself become fusible by the combination
of carbon, with which it has been impregnated by the fuel, it melts as
it reaches the point of fusion, and settles down in the lowest part of
the furnace, otherwise called the hearth. It is followed by the scoria,
slag, or ‘cinder’ (as it is always called in the trade), composed of the
flux, the foreign matter of the ores, and the ashes of the fuel, which
are now in a vitrified state; and this artificial lava, being of much
less specific gravity, rests on the surface of the iron and protects it
from the action of the blast. The furnace is ‘continued in blast,’ that
is to say, in full operation, and must be fed equably and constantly
night and day, till the manufacturer thinks fit to blow it out, either
for the purpose of repairing it, or of reducing his make of iron. At
certain intervals, generally twice in the twenty-four hours, the furnace
is tapped; that is to say, the stoppage of sand which closes an orifice
at the bottom is knocked away, the liquefied metal rushes out, and is
guided successively into moulds of sand in the form of short thick bars,
which, by a rude metaphor, as old as the invention of casting, are
called ‘pigs,’ while the main channel down which the red-hot torrent
flows is called the ‘sow.’
Footnote 57:
‘Quarterly Review,’ vol. cix. p. 114.
The invention of the hot blast gave a new and mighty impulse to the
production of iron. Though Mr. Scrivenor[58] mentions the remarkable
fact that in the furnaces of Peru a contrivance has been noticed for
letting the air pass over hot coals, and thus become heated in its
passage to the fire, yet it was personal observation, and not
archæological research, that, in 1829, suggested to Mr. Neilson, of the
Clyde Iron Works, the possibility of economising fuel by substituting
hot for cold air in blowing his furnaces. Before this important
discovery more than eight tons of coke had been required to produce one
ton of pig-iron; but on heating the blast, previously to its entering
the smelting-oven, to a temperature of 300° F., it was found that a
saving of two and a half tons of coal could be made on every ton of
iron, and on raising it to the temperature of 600° F.—a heat somewhat
more than sufficient to melt lead—a still more considerable saving of
fuel was effected, while at the same time the important discovery was
made that at this high temperature bituminous and even anthracitic coal
might be used instead of coke. Another advantage was that the same steam
power now sufficed for applying the blast to four furnaces which had
formerly been required for three; and the total result of the
improvement was a saving of 72 per cent. of fuel. Thus we have here
another instance of the important results that may be gained from a
single good idea when worked out by clever practical men, for the hot
blast has most assuredly increased the wealth of England by many
millions a year!
Footnote 58:
‘History of the Iron Trade.’
Another circumstance likewise tended considerably to increase the
production of pig-iron. It was found that the hot blast not only had
power sufficient to produce in the raw coal the requisite intensity of
heat, but also to expel from it, to a certain extent, the sulphur, which
injured the quality of the iron, and thus a great economy in labour as
well as in the quantity of fuel was effected. Since then the black-band,
an iron-stone found in great quantities in Scotland, and also, to a less
extent, in Wales, but not readily convertible into iron by the old
methods, and also the Northamptonshire and the Cleveland ores,
discoveries of a later date and of an incalculable extent, have been
made by the hot blast to yield their iron in great abundance.
The power of using the black-band alone in the furnace, and not, as
before the introduction of the hot blast, in small quantities only, and
combined with other ores, constituted a new era in the manufacture of
iron, and gave to Scotland, till then an iron-making district of little
importance,[59] the pre-eminence over all others for the production of
soft fluid iron, best suited to ordinary founding purposes.
Footnote 59:
The metal was formerly so scarce in their country that in the times of
the Edwards the Scotch were accustomed to make predatory incursions
into England for the sake of the iron they could carry off. Now they
not only manufacture sufficient for their own use, but actually export
above half-a-million tons.
The Cleveland district, formerly unknown in metallurgy, is now the seat
of a vast industry, keeping more than a hundred furnaces in blast.
The head-quarters of this new iron-country are established at
Middlesborough, on whose site there existed but one house in 1829, but
which in 1861 had grown into a town of 24,000 inhabitants, and still
increases at the rate of 1,000 a year. Branch railways bring the stone
here for smelting from all the neighbouring quarries, and the dense
cloud of smoke that hangs over the place serves as a land-mark, not only
from the high ground of Yorkshire, but even from some parts of
Westmoreland.
But Middlesborough, ‘the youngest child of England’s enterprise’ as it
has been called by Mr. Gladstone, is by no means one of the loveliest of
her offspring. Scarcely a blade of grass and not a single tree relieves
the dull monotony of its dreary streets of small houses, darkened by
perpetual smoke, which, as the wind sways it, affords, at rare
intervals, glimpses of distant hills or of the Tees, serving only to
make the prison of a town more gloomy. Mines and furnaces have also been
established in other parts of the district—in Rhosdale, at Grosmont near
Whitby, and elsewhere—and not a year passes without the opening of new
veins and the rising of new smoke-clouds amid the lovely dales of north-
western Yorkshire. The iron which eventually finds its way to
Middlesborough is sent thence to every part of the world. Its quality is
essentially inferior to that derived from the coal-measures; but for
ordinary purposes, and for mixing with the finer classes, it is of great
value. Looking to the future, we cannot doubt that the Middlesborough
district is destined to have no rival in any part of the world, for even
now its works compete in magnitude with those of our old iron fields.
A material which had hitherto been thrown away was also, by the agency
of the hot blast, made available for the purposes of the iron master.
The ‘tap cinder,’ or refuse of the puddling furnace, which is not to be
confounded with the cinder of the blast furnace, contains a considerable
percentage of metal, and when thrown again into the furnace greatly
increases the yield, though it proportionally deteriorates the quality
of the iron. The results of all these successive discoveries and
innovations, aided by the facilities of transport afforded by canals and
railroads, are truly astonishing.
The make of iron which, on the introduction of steam, had suddenly risen
to nearly 50,000 tons per annum, reached 125,000 in 1796, and in 1806
had advanced to nearly 260,000. In 1825 the make was nearly 600,000
tons; in 1840 it amounted to 1,300,000 tons; and in 1854 to 2,700,000
tons. In 1865 it reached the enormous figure of 4,819,254 tons—as much
as the combined production of Continental Europe and the United States;
and there is little doubt that the present yield does not fall much
short of 6,000,000 tons! A similar colossal expansion is without a
parallel in the annals of metallurgic industry.
The chief districts which furnish this incredible quantity of iron are
situated in Yorkshire, South Wales, Staffordshire, Durham, Lancashire,
Cumberland, Shropshire, Derbyshire, and the West of Scotland.
The number of furnaces in blast in 1865 were, in England 376,
distributed over 176 iron-works; in Wales 135, distributed over 49
works; and in Scotland 141, over 32. To supply these furnaces there were
raised 9,910,045 tons of ore, the estimated value of which at the place
of production was 3,324,804_l._, that of the pig-iron, at the mean
average cost at the place of production, being 12,048,133_l._
Of the iron-stone, 1,384,500 tons were argillaceous carbonate from the
coal-measures of Staffordshire and Worcestershire; 3,166,000 tons from
the Yorkshire mines; nearly 1,500,000 tons from the coal-measures of
North and South Wales, and 1,500,000 tons argillaceous carbonate from
Scotland.
Of the red hematites of Whitehaven and Ulverstone, which consist almost
entirely of peroxide of iron, and are reckoned among our best ores,
214,433 tons were smelted at the spot, and 937,386 tons exported for the
supply of Staffordshire, South Wales, and other districts.
The brown hematite (brown oxide of iron) of the Forest of Dean, where
the ore exists in almost unlimited quantity, is raised exclusively for
shipment to the iron-works of South Wales. Though not rich, yet, from
the great masses in which it is found, its cost of production is very
low.
The finest iron ores, such as the black oxide or magnetite, specular
iron, and spathose iron, or sphærosiderite, which furnish the best kinds
of iron, are unfortunately but of rare occurrence in Great Britain.
As we see by the following table[60] of the production of cast iron in
the chief European mining States—
┌───────────────┬──────┬──────────┬──────┬──────────┐
│Countries │ Years│ Tons │ Years│ Tons │
├───────────────┼──────┼──────────┼──────┼──────────┤
│Great Britain │ 1840│ 1,400,000│ 1865│ 4,527,000│
│France │ 1845│ 271,000│ 1864│ 1,213,000│
│Prussia │ 1835│ 32,800│ 1865│ 772,000│
│Belgium │ 1845│ 134,500│ 1864│ 450,000│
│Russia │ 1838│ 171,000│ 1865│ 278,000│
│Austria │ 1835│ 200,000│ 1865│ 259,000│
│Sweden │ 1835│ 97,500│ 1865│ 227,000│
│Spain │ 1850│ 26,000│ 1865│ 48,000│
│Italy │ 1838│ 20,000│ 1865│ 27,000│
└───────────────┴──────┴──────────┴──────┴──────────┘
France occupied the next rank to Great Britain in 1864; but since 1866
Prussia, besides the rapid development of the iron industry in
Westphalia and the Rhenish provinces, has acquired new and valuable
mines by the annexation of Hanover and Nassau. Her production had
consequently risen to 1,000,000 tons in 1868, and probably the time is
not far distant when she will have outstripped France. Nassau possesses
inexhaustible supplies of specular iron ore of a remarkable purity,
which not only feed the blast furnaces of Westphalia, but are also
largely exported to England.
Footnote 60:
From the official reports of the International Jury of the Universal
Exhibition of 1867 in Paris.
In proportion to the smallness of her territory Belgium rivals Great
Britain in the production of iron, supplied exclusively by the brown
oxide (brown hematite), and surpasses the vast empire of the Czar.
But Russia has the advantage over all the countries previously mentioned
of possessing inexhaustible deposits of magnetic iron ore (magnetic
loadstone—magnetite) which affords bar-iron of the very best quality;
and though hitherto the immense distances which separate the mines from
the larger centres of consumption have retarded the progress of the iron
manufacture, the construction of railroads is gradually overcoming these
obstacles, and possibly even the now unworked Siberian mines of the
Altaï and of Transbaikalia, where coal is found along with iron, may
acquire importance at a not far distant time. At present the chain of
the Oural (Permia and Orenburg) furnishes nine-tenths of all the iron
produced in the empire. The most remarkable of the Ouralian mines is the
famous magnetic mountain Wissokaja Gora, in the neighbourhood of Nishne-
Tagilsk, which Peter the Great bestowed in 1702 on the armourer Nikita
Demidoff of Tula, along with a vast extent of forests and arable land.
This magnetic mountain or hill, which is 300 fathoms long, 250 broad,
and 240 feet high, rises from the midst of a plain, in the form of a
broad, flat eminence. It consists almost entirely of _pure magnetic iron
ore_, and is worked like an open quarry; but, on account of its
hardness, the ore requires to be blasted with powder. Although many
millions of tons have been extracted from it since it first came into
the possession of the Demidoff family, it may easily be imagined that a
mass of at least 600,000,000 cubic feet of iron-ore is not easily
removed, and will outlast the labours of many generations. The quantity
of cast-iron annually produced amounts to 25,500 tons, which is
converted, partly at Nishne-Tagilsk and partly in the neighbouring
forges, into bar-iron, anchors, kettles, scythes, nails, wire, &c. The
excellent quality of the iron allows it to be rolled into very thin
plates, which are frequently made use of in Russia for the roofing of
houses, and are also manufactured at Nishne-Tagilsk into lacquered
wares, which find a ready sale throughout the whole of European and
Asiatic Russia.
The iron-working industry of Austria has its chief seats in Styria,
Carinthia, Transylvania, and Bohemia, and, though out of proportion with
the vast natural resources of the empire, has of late made rapid
progress. The ores, which are of an excellent quality, are mostly
smelted with charcoal, as they are generally situated at a great
distance from the coal mines. The Noric or Styrian iron has enjoyed an
excellent reputation ever since the time of the Romans, when the
imperial manufactory of Laureacum on the Danube supplied the legions
with swords and javelins.
In a pass of the Styrian Alps, between the valleys of the Mur and the
Enns, lies one of the most remarkable iron mines in the world, the
famous Erzberg or iron-mountain, which rises to a height of 3,000 feet,
and whose summit and sides are almost everywhere coated with a thick
mantle of the richest ore. Authentic records show that it has been
worked ever since the year 712; and probably the Romans derived a part
of their Noric iron from this source, as the ore is not here concealed
in the bowels of the earth, but crops out on the surface, near a
mountain pass which was undoubtedly known to them. As at Nishne-Tagilsk,
the ore thus conveniently situated is quarried from the mountain, and
thus in course of time extensive excavations or grottoes have been
formed all over its surface, affording a most interesting spectacle. The
bottom of these iron-stone pits is irregularly strewn with large blocks
of ore through which wind narrow footpaths. Roads lead from one pit to
the other, and close by are situated the small huts in each of which ten
or twenty of the miners sleep as long as the working season lasts, for
their families generally live lower down in the deeper valleys. On the
top of the mountain stands a colossal crucifix of iron, near which an
annual thanksgiving feast is celebrated. Though the mines are easily
worked, the conveyance of their produce to the smelting-ovens of
Eisenerz and Vordernberg is a matter of much greater difficulty, and
requires numerous tram-roads, galleries, and shafts, through which the
ore is precipitated from a higher to a lower level. At the foot of the
mountain they all unite in one main shaft, which leads into a gallery
ornamented with a monumental gate. Thus the whole of the Erzberg is
covered with various machines, pits, horizontal and vertical galleries,
tunnels, and roads, and represents as it were a _mine turned inside
out_, where all the operations which are elsewhere performed underground
are, as at the Carclaze tin-mine in Cornwall, exposed to the open day.
Here, instead of dirty and dangerous ladders, convenient footpaths,
bordered with trees and illumined by the sun, lead from gallery to
gallery and from pit to pit, and instead of being confined in dismal
passages, the miner enjoys magnificent views of the grandest Alpine
scenery. The annual produce of the Erzberg amounts to 25,000 tons of
excellent iron, as the ore (sparry iron, carbonate of iron,
sphærosiderite) is nearly as pure as the magnetic iron-stone of Russia,
and affords natural steel with the greatest facility. The railroad now
being built in Styria will no doubt greatly increase this production,
which might be continued for many thousand years without exhausting the
vast mineral wealth which Nature has here deposited.
Though Sweden furnishes but an insignificant quantity of iron when
measured by an English scale, yet, in point of quality, its produce is
unrivalled in the world. The purest iron-ores (magnetic iron-stone)
abound in the mountain chains which traverse the kingdom, and immense
forests afford almost inexhaustible supplies of charcoal for their
smelting, so that hitherto the want of roads has alone prevented the
production of iron from attaining dimensions equal to the natural
resources of the country. Many of the richest mines, particularly in the
more northern provinces, have never yet been worked, as for instance the
enormous mounds of magnetic iron-ore at Gellivara (67° N. lat.) in
Swedish Lapland, beyond the Arctic circle, which, from their situation
in a polar desert, have hitherto been totally useless. In 1865 an
attempt was made to utilize them by means of a railroad and the
canalization of the river Luleo, but after a heavy expense the works
were finally abandoned.
Thus the manufacture of iron, which, under more favourable
circumstances, would reach as far as its ores extend, is confined to
Dalecarlia, the more central provinces of Kopperberg, Wermland, and
Upsala, where the celebrated mines of Dannemora, which furnish the fine
Oeregrund iron, largely imported into England for the manufacture of
steel, deserve our particular notice, both for their ancient renown and
their wild and colossal grandeur. An excellent road leads from the
famous university town of Upsala to Old Upsala, old and hoary in the
fullest sense of the word, for its church dates from the Pagan times,
and close by rise three tumuli which, according to popular tradition,
contain the remains of no less important personages than Odin, Thor, and
the divine Freya.
Further on towards the north-east, six geographical miles from Upsala,
lie the iron-works of Oesterby, remarkable for their beautiful situation
in a natural park of forests and lakes, and thence half an hour’s walk
over the plain brings one to the far-famed pit of Dannemora.
The country around is perfectly level, a succession of pine-woods and
open grounds, and no sign announces the vicinity of the mine, until at
length the traveller sees a few huts and some machines for lifting the
ore, and then suddenly stands on the brink of an enormous pit, or rather
of a vast crater, whose black and precipitous walls inclose an area of
at least a mile in circumference. On looking down into the abyss, which
descends to a depth of 450 feet, and is here and there enlivened with
patches of perennial snow, he perceives along its black walls the still
blacker entrances to labyrinthine caves fringed in some parts with long
stalactites of ice of aquamarine transparency and colour. From some of
these hollows the flames of piles of fir-wood are seen to creep along
the hard rock which they are to soften, and the deep gulf is animated by
troops of miners, the distant clang of whose hammers, closely resembling
the clicking of a number of clocks, forms a strange concert with the
creaking noise of the machinery. Attracted by the novelty of the
interesting sight, the eye wanders from one object to another, and time
steals on rapidly and unperceived—when suddenly a bell tolls, and the
scene as suddenly changes.
It is noon, and the tuns, which before were hauled up from the deep
laden with ore, are now seen ascending with a living freight—men, women,
and children—standing quite unconcernedly on the narrow edge of the tub,
and holding with one hand the chain to which it is attached.
Soon a deathlike silence reigns in the pit—a striking contrast with the
noise and life it erewhile displayed—and now loud shouts are heard,
warning all those who may have remained behind that the battery prepared
during the previous working hours is about to explode. Again a profound
silence—and then loud thunder bursts forth, with many an echo, from the
depth of the abyss.
For several minutes the whole neighbourhood trembles as if shaken by an
earthquake. Through the black clouds of smoke which ascend from the
gulf, pieces of stone or ore are hurled upwards, frequently far beyond
the brink of the pit, and most of the detonations are followed by the
crash of the falling fragments rent by the explosion from the mother-
rock.
For many centuries this remarkable mine has afforded employment to many
hundreds of workmen, without showing any signs of exhaustion, for its
mighty mass of magnetic iron-ore descends to an unknown depth and seems
to be practically inexhaustible.
Though the mineral resources of Spain are immense, yet its iron-industry
is so little developed that more than two-thirds of the excellent ores
of Biscay, instead of being smelted in the country, are exported to
France and England.
In Italy the red oxide and magnetic iron-stone mines of Elba have been
celebrated since the remotest antiquity, but, from the want of fuel on
the island, their entire produce, which amounts to about 100,000 tons,
is exported to the coast of Italy, to France, and to England. The
principal mines are situated on the slope of a steep mountain fronting
the sea, and are divided by horizontal terraces into five stories or
huge steps communicating with each other by means of oblique roads, on
which carts convey the ores to the shore. Though worked for more than
2,000 years, the mines, which occupy about 700 workmen, are apparently
able to supply the wants of the remotest posterity.
On turning to America we find the United States making gigantic strides
in the extension of their iron manufacture, which has risen from 347,000
tons in 1840 to 1,200,000 tons in 1864; and as here none of the elements
of progress are wanting—a boundless mineral wealth, liberal
institutions, which allow the freest scope to individual energy, and an
unrivalled spirit of enterprise—there can hardly be a doubt that finally
the United States must become the first iron-country in the world. The
masses of magnetic iron-stone and red oxide which extend along Lake
Superior, over a length of 120 miles and a breadth of from five to
thirty, would alone suffice to provide for the wants of the whole of the
human race for many thousands of years. They only began to be worked in
1849; and in 1866 the railroad which leads from the mines transported
204,454 tons of ore.
The thriving town of Marquette, the central point of this new seat of
industry, was, scarcely twenty years ago, a complete wilderness, where
the Red Indian pursued the beasts of the forest, unconscious that the
treasures concealed beneath his natal soil would one day be the cause of
his expulsion from the hunting-grounds of his fathers.
The State of Missouri possesses two ‘iron-mountains’ similar to the
magnetic mountain of the Demidoff: one of them called Pilot Knob is 600
feet high, the other 220. An immense mass of magnetic oxide has also
been discovered in California, near the northern extremity of the Sierra
Nevada. But though iron is found in abundance in many parts of the
Union, (Tennessee, North and South Carolina, Georgia, &c.), the States
of New York and Pennsylvania produce by far the greatest quantity.
Brazil and the island of Cuba likewise contain vast deposits of the
richest iron-ores; and in Mexico we find the famous Cerro del Mercado,
an iron-mountain 633 feet high, which rises in grotesque form from the
valley of Durango. This wonderful mound has been calculated to contain
3,244,000,000 cubic feet, or 454,000,000 tons, of magnetic iron ore,
capable of yielding 290,000,000 tons of cast iron, or more than fifty
times the annual production of Great Britain! A more industrious and
civilised race would here find a boundless field for profitable
employment; but the indolent Mexican, steeped in ignorance and falling
from one revolution into another, still leaves these treasures almost
untouched, and, neglecting the vast resources of his country, draws
nearly his whole supply of iron from the distant forges of Great
Britain.
CHAPTER XXIX.
LEAD.
Its Properties and extensive Uses—Alston Moor—Belgian Lead Mines—Galena
in America—Extraction of Silver from Lead Ores—Pattinson’s Process—A
great part of our wealth is due to the laboratory.
Lead was but little prized by the ancients, who, unacquainted with
gunpowder, needed no bullets for war or for the chase. The history of
its first discovery is lost in obscurity, but it probably became known
much later than copper or tin, as less metallurgic skill is required for
the smelting of the cupreous or stanniferous ores than for the reduction
of galena or sulphide of lead, which is the most abundant of the
plumbiferous ores, and may indeed be regarded as the only commercial ore
of any value, if we except the carbonates, which are probably formed by
its decomposition.
Lead, however, is mentioned both in the Book of Job and in the fourth
book of Moses, ‘Oh! that my words were graven with an iron pen on
tablets of lead,’ exclaims the long-suffering patriarch, and the
legislator of the Jews commands his people to ‘make go through the fire,
gold, silver, brass, tin, and lead, and everything that may abide it.’
The Phœnicians, who provided Greece and Egypt with Spanish lead,
frequently made use of this metal to increase the weight of their
anchors; and Herodotus, describing a bridge in Babylon, mentions that
its stones were fastened with clasps of iron soldered with lead. The
physical properties of this metal qualify it for a great variety of
uses. As it is but little altered by exposure to air or water, it makes
excellent pump-tubes and rain-gutters; while its considerable weight,
its softness, its flexibility, and the facility with which it melts at a
comparatively low temperature render it an invaluable material for the
soldier’s bullet or the huntsman’s shot. Combined with oxygen it forms
the pigment called red-lead, or minium, and united with carbonic acid
white-lead, or ceruse, which is still more frequently used in painting.
In the manufacture of glass and crystal it plays an important part, as
it forms one of the chief ingredients of flint-glass and crown-glass, of
which, as is well known, the achromatic lenses are made which have so
wonderfully improved the distinctness of our telescopes. United with tin
it forms an alloy which is more fusible than either metal alone, and
which is consequently used as a solder by the plumbers, while with
antimony it combines into a hard mass which serves to make letters for
the printing-press. All these various uses absorb immense quantities of
lead, and render it one of the most valuable products of the
subterranean world.
Among the lead mines of Europe we find the first rank occupied by those
of Spain, which in 1863 furnished the enormous mass of 309,940 tons of
galena. The principal mines are situated in Guipuzcoa, Catalonia,
Arragon, the Sierra Morena, and, above all, in the mountain chain of the
Alpujarras, where the rocks of the Sierra Gador are everywhere traversed
by veins of galena. The production of North Germany is also very
considerable. In 1865 Prussia furnished 57,808 tons of galena, and the
Hanoverian Hartz Mountains, which produced 101,411 tons in 1864, and now
belong to the same monarchy, have raised its previous production to a
threefold amount.
The chief lead mines of England are situated near Alston Moor, where the
three counties of Northumberland, Durham, and Cumberland meet together.
The lofty hills of the district, bare of wood and almost wholly covered
with marshy heaths, are intersected by the valleys through which run the
Tyne, the Wear, and the Tees, with their numerous branches. The country,
though little frequented by tourists, is wild and picturesque; but the
deep gorges with which it is furrowed have more than a mere romantic
interest, for they lay open to view numerous veins of ore, and direct
the operations of the miner to the places where it is sufficiently
abundant to reward his toil. The town of Alston, the mining centre of
the district, is beautifully situated close to the river Tyne, which,
about five miles above it, ascends, between lofty hills, to the foot of
Cross Fell, this picturesque mountain giving a character of considerable
grandeur to the surrounding scenery. The mines of the Alston Moor
district produce annually about 25,000 tons of lead. The waters are
drawn off by long adit levels, and the ores are dragged out by horses to
the day. This region extends southward to the Yorkshire valleys of
Swaledale, Arkendale, and to Grassington, where numerous lead mines are
worked under very similar circumstances. The Yorkshire mines yielded in
1856 8,986 tons of lead.
Another important lead district lies in the northern part of Derbyshire,
in the hilly country of the neighbourhood of the Peak, so well known and
so often visited for its picturesque beauty. The mines of Derbyshire,
which yield annually 5,000 tons of lead, are getting exhausted; they are
very numerous, but in general inconsiderable.
Next to Alston Moor the lead mines of Flintshire and Denbighshire are
the most productive, furnishing annually nearly 6,000 tons of lead. An
important group of veins of lead occurs in the slaty rocks of
Cardiganshire and Montgomeryshire, all of which have an E.W. direction;
although so far from parallel that they often meet, and frequently form
at such points of intersection ‘courses’ of ore. Some of these mines
were very profitably worked in the seventeenth century, and during the
last thirty years several of them have been highly productive.
There are considerable lead mines in the south of Scotland, at
Wanlockhead and Leadhills in Lanarkshire; and those of Strontian, in
Argyleshire, likewise deserve to be noticed. The Isle of Man has two
important lead mines, the Foxdale and Laxey, the former remarkable for
the great size of its main lode. The elevated tracts of Wicklow likewise
contain some valuable lead mines, at Luganure and Glenmalure. In 1866
the total produce of our lead mines amounted to 91,047 tons of galena,
which yielded 67,390 tons of metal.
The island of Sardinia, already renowned among the ancients for its rich
lead mines, produces about 15,000 tons, or nearly as much as France,
where however the extraction of galena has of late years made
considerable progress.
Belgium, which in 1841 produced no more than 34 tons, raised in 1864 no
less than 16,780 tons, chiefly from the mines of Bleyberg-à-Montzen,
situated in the carboniferous limestone near Verviers. To render these
rich deposits available, vast difficulties had to be surmounted by the
united powers of enterprise, capital, and engineering skill. Rivers and
brooks, diverted from their ancient course, were made to flow through
new water-tight channels, and such is the amount of drainage required in
that aquiferous region that engines of two thousand horse-power have to
raise from a depth of 360 feet a daily quantity of 800,000 cubic feet of
water.
In Greece the immense mounds of scoriæ accumulated near the ancient
silver mines of Laurium, have been found to contain about ten per cent.
of lead. Their total mass is estimated at no less than 3,000,000 tons,
and they afford a convincing proof both of the importance of the ancient
silver production of Attica, and of the imperfection of the old Athenian
mining operations. A French company has lately been formed for smelting
this prodigious accumulation of scoriæ, once cast aside as rubbish.
In Siberia the famous lead mines of Nertschinsk, where many an
unfortunate exile is doomed to end his days, are worked merely for the
silver contained in them.
In South America, the Chilian lead mine of Mina Grande, near Coquimbo,
is renowned for its extreme richness, and Brazil has considerable veins
of galena, in the province of Minas Geraes; but probably the United
States of North America (Wisconsin, Arkansas, Iowa, Illinois), possess
the largest galena deposits in the world. In Wisconsin, they extend all
over a vast territory of more than 4,000 square miles. As yet the works
are conducted in the most negligent manner, by a crowd of adventurers.
In winter, when the air in the pits is more salubrious, and agricultural
labour ceases, needy farmers, bankrupt traders, and thriftless artisans
flock from all parts to the lead country for the purpose of repairing
their broken fortunes. In summer when malaria renders the pits extremely
unhealthy, this nomadic population melts away like chaff before the
wind. Yet, in spite of the rough mode of extraction which prevails in
the American lead country, the mines of Iowa, Wisconsin, and Illinois
yielded about 20,000 tons of lead in 1866, and their produce is
constantly increasing.
In all lead mines, the galena often occurs in pieces so large that they
do not require to be separated from the veinstone by the processes of
stamping and washing. They are then called _pure ores_, and the most
simple preparation is sufficient to prepare them for the smelting
furnace. When the ore has been picked and so far prepared, it is first
roasted or heated in a reverberatory furnace, an operation which causes
the oxygen of the air to combine with the two elementary bodies of which
galena is composed. After undergoing this chemical change, the ore is
now mixed with coke, charcoal, or peat, and reduced by smelting in a
small blast furnace of a peculiar kind. Under the influence of heat, the
carbon of the coal, uniting with the oxygen of the ore, flies off in the
form of carbonic acid gas, while the metallic lead, which in the finer
ores amounts to 70 or 80 per cent., sinks to the bottom of the furnace.
Almost all the varieties of galena contain a greater or less proportion
of silver, which it is often found worth while to separate from them.
This process is at present effected according to a most ingenious
method, founded on the circumstance first noticed in the year 1829, by
the late H. L. Pattinson, of Newcastle-on-Tyne, that when lead
containing silver is melted in a suitable vessel, afterwards slowly
allowed to cool, and at the same time kept constantly stirred at a
certain temperature near the melting point of lead, crystals begin to
form. These, as rapidly as they are produced, sink to the bottom, and on
being removed are found to contain much less silver than the lead
originally melted. The still fluid portion, from which the crystals have
been removed, will at the same time be proportionally enriched. By
repeated meltings and crystallisations in a series of cast-iron pots
with fire-places beneath, the workman is thus able to deprive almost
entirely of its silver by far the largest portion of the lead operated
upon, while the remainder becomes an exceedingly rich alloy of both
metals, so as to contain fifty times its original proportion of silver.
This rich lead is subsequently exposed in a refining furnace to a strong
blast of air at a high temperature, fresh supplies of lead being
constantly introduced as the operation proceeds. By this means the lead
becomes rapidly oxidized and converted into litharge, which partly runs
off in the fluid state, and is partly (about 10 per cent.) lost by
sublimation, while the silver forms a cake at the bottom of the cupel.
The brightening of the silver, which lustrously shines forth at the
moment of the separation of the last traces of lead, indicates the
precise period at which the operation should be ended, and the blast is
then turned off and the fire removed from the grate. Before the
introduction of Pattinson’s ingenious process, the separation of the
silver from the lead was attended with a much greater loss of the latter
metal, as greater quantities had to be cupelled to effect the same
result. The economy obtained amounts to no less than 98 per cent.; for
where formerly 100 cwt. of lead were lost by sublimation, the same
quantity of silver is now obtained with a loss of no more than 2 cwt.,
and at the same time with a considerable saving of fuel.
Ores very poor in silver, as for instance those of Alston Moor or
Derbyshire, which formerly could not be profitably cupelled, are now
advantageously treated by the Pattinson process. This is but one example
of the valuable practical results which may be obtained from a single
scientific discovery. But chemistry has introduced thousands of similar
technical improvements in almost all branches of manufacturing industry,
and were we to add together the profits thus obtained, we should find
that a great part of our wealth is due to the laboratory.
CHAPTER XXX.
MERCURY.
Not considered as a true Metal by the Ancients—Its Properties and Uses—
Almaden—Formerly worked by Convicts—Diseases of the Miners—Idria—Its
Discovery—Conflagration of the Mine—Its Produce—Huancavelica—New
Almaden.
Among the metals known to antiquity mercury was the last discovered. It
is mentioned neither in the Bible nor in Homer, who accurately, though
briefly, describes the characters and uses of all the other ancient
metals; but we learn from the works of Aristotle that its discovery must
have preceded the times of Alexander the Great.
From its always remaining fluid in the temperate climates of the earth,
it was, however, not considered as a true metal; for the ancients had no
means of ascertaining that at the low temperature of -39° Fahr., it
becomes malleable and assumes the solid form. The Greeks called it
Hydrargyros or _water-silver_, from its fluidity and argentine colour;
the Romans, ‘argentum vivum,’ or live silver, from which our
‘quicksilver’ has been derived, and in the Middle Ages the alchemists
gave it the planetary name of Mercury, which has been generally adopted
in modern scientific language.
At a very early age cinnabar (sulphide of mercury), the beautiful
scarlet ore from which it is chiefly obtained, was employed by the
ancients as a colouring material for imparting a florid complexion to
triumphant generals or to guests at the festive board. The extent to
which this cosmetic was used may be inferred from the facts mentioned by
Pliny, that the Greeks imported red cinnabar from Almaden 700 years
before the Christian era, and that Rome in his time received 700,000
pounds from the same mines.
As the alchemists considered quicksilver as the fittest substance for
transmutation into gold, it became the subject of innumerable
experiments; and though these manipulations had not the desired effect,
they accidentally led to the discovery of several of its combinations,
which soon became known as powerful medicines. But it was reserved for
modern times to appreciate and understand the full importance of
mercury, and to extend the field of its utility to a variety of uses
unknown to former ages.
Alloyed with tin-foil, it forms the reflecting surface of looking-
glasses; and by its ready solution of gold and silver, and subsequent
dissipation by a moderate heat, it becomes the great instrument of the
arts of gilding and silvering copper and brass. The same property makes
it available in extracting these precious metals from their ores. To
science it is a substance of paramount value. Its great density, and its
regular rate of extension and contraction by increase and diminution of
temperature, give it the preference over all liquids for filling
barometer and thermometer tubes, so that without mercury we should know
but little indeed about the laws of caloric and of atmospherical
pressure. In chemistry it furnishes the only means of collecting and
manipulating, in the pneumatic trough, such gaseous bodies as are
condensible over water. To its aid, in this respect, the modern
advancement of chemical discovery is pre-eminently due, and without its
assistance many a branch of industry which now greatly adds to the
wealth of the nation could never have existed.
Mercury does not rank among those metals which are copiously
disseminated over the surface of the earth. Considerable deposits or
veins of even its commonest and most abundant ores (red cinnabar;
hepatic cinnabar) are confined to a few spots, and all Europe possesses
but two important quicksilver mines—at Almaden in Spain, and Idria in
Carniola.
The Sierra Morena or the Black Mountains in the Iberian Peninsula, so
well known as the scene of the exploits of Don Quixote, are no less
renowned in the mining world for their subterranean riches, among which
the famous quicksilver mines of Almaden del Azogue hold a conspicuous
rank. This small town of about 10,000 inhabitants is situated on the
northern border of the above-mentioned mountain chain, at the south-
western extremity of the province of New Castile, and, unlike most other
Spanish cities, affords the pleasing sight of well-built houses and
clean and regular streets. As is generally the case in mining districts,
the neighbourhood is sterile, but picturesque, and from the neighbouring
mountains magnificent prospects open on every side.
The mines of Almaden, after having been the property of the religious
knights of Calatrava, who had assisted in expelling the Moors, were
farmed off to the Fuggers, the celebrated merchant princes of Augsburg,
whose descendants still rank among the high aristocracy of Germany.
Afterwards, from the date of 1645 till the present time, they have
either been worked on Government account or farmed off to private
companies. A visit to these celebrated mines is highly interesting. A
spacious tunnel or gallery, completely walled with solid masonry, leads
into the bosom of the mountain and branches out at its extremity into
several galleries hewn in the slate which forms the matrix of the vein.
One of these galleries conducts to the Boveda de Santa Clara, a vast
circular hall in which formerly stood a horse-gin, for raising the ore
to the surface. At present, however, this work is performed through a
shaft which descends to the lowest level of the mine. From another
gallery convenient stairs lead down to the first working level of the
mine, and thence short ladders to the deeper stories. The shafts are
wide, the galleries high enough to allow one to walk upright through
them. The upper stories are almost thoroughly dry, the lower ones humid;
the water, however, is easily removed by hand-pumps, which raise it from
story to story into a large subterranean reservoir, emptied once a week
by a steam-engine of fifty-four horse-power. The veins are so extremely
rich that, though they have been worked pretty constantly during so many
centuries, the mines have hardly reached the depth of 1,140 feet. The
lode actually under exploration is from fourteen to sixteen yards thick,
and it becomes thicker still at the crossing of the veins. Its present
annual produce amounts to about 80,000 cwt. of pure mercury. The ore
presents a beautiful sight in the galleries where it is worked, on
account of the dark red glittering colour of the cinnabar, which is
sometimes earthy and sometimes forms compact crystalline masses, or fine
crystals mixed with calcareous spar. Often when a hewer detaches a block
of ore with his pickaxe, quicksilver masses of the size of a pigeon’s
egg roll from a crevice in which they were lodged, and, leaping along
the floor, divide into thousands of small drops. This, however, is no
loss, for all the rubbish which accumulates in the galleries is
carefully collected.
The ores are treated in thirteen double distillatory furnaces, called
alodels, and yield only ten per cent. upon an average. But the analysis
of the ores leaves no doubt that the barbarous apparatus employed in its
sublimation causes a loss of nearly one-half of the quicksilver, which
is dispersed in the air, to the great injury of the workmen’s health.
This apparatus has remained without any material change for the better
since the days of the Moorish dominion in Spain. The furnaces are heated
with brushwood, particularly with the resinous branches of the _Cistus
ladaniferus_, which grows over the greatest part of the surrounding
mountains. This dark evergreen shrub often extends over many miles of
ground, and when in flower covers the hills with a beautiful snow-white
carpet.
Formerly only criminals condemned to hard labour for life were employed
to work in the mines of Almaden. At sunrise they were conducted from a
prison, which still exists, through a subterranean passage into the
mines, where they were obliged to toil till evening, when they were led
back again to their dungeons, so that they never saw the light of day.
After a few years these poor wretches generally died from inhaling the
poisonous vapours of the mercury. Reduced to despair, they set fire, at
the beginning of the last century, to the galleries, which were then
constructed of wood, and thus rendered the mining operations impossible
for many years. Since then only free miners are employed, who are well
paid, and not allowed to work longer than six hours a day. Most of them,
however, die at an early age, between thirty and forty, and those who
live longer are affected by a spasmodic trembling, so as to be unable to
keep a limb quiet.
After the mines of Almaden those of Idria in Carniola are the richest in
Europe. This neat little town lies in one of the largest and most
picturesqe basins of the Julian Alps. The gigantic and naked rock walls
which inclose the sequestered valley are only partially decked along
their summits with clumps of firs; but lower down the slopes are covered
with beautiful meadows and forests, and here and there on the projecting
spurs of the mountains stand picturesque chapels, which serve to
heighten the beauties of the magnificent panorama.
Chance—to which man owes so much both of good and evil—also led to the
discovery of the subterranean treasures of Idria. In the year 1497 a
peasant found, in a tub which he had placed under a brook, some drops of
a heavy liquid shining like silver. Although quite ignorant of the value
of his discovery, he still was cunning enough to carry them to a
goldsmith without mentioning the place where he had found them. At
length a man named Anderlein, having promised him a handsome reward,
became master of the secret, and associating himself with several
wealthy persons, began to work the mine. After several years the
property passed into the hands of a company of goldsmiths of Salzburg
and Augsburg, which derived such profits from the mine as to excite the
greed of the neighbouring Venetians, who in the year 1510 forcibly drove
away the Germans, but were soon after expelled by the Emperor
Maximilian, who, as soon as he heard of this insolent attack, sent some
troops into the forest of Idria and restored it to its rightful owners.
In 1578 the mine was incorporated among the domains of the State, and
began to be worked with greater regularity.
The entrance lies to the south of the town, on the slope of a small hill
projecting from the circular zone of mountains which gird the basin. The
visitor may either descend, in less than five minutes, to the bottom of
the pit, through a perpendicular shaft, in one of the large tubs which
serve to raise the ore, or he may make use of convenient stairs. Here
and there are landing-places, whence galleries lead to the various
fields or stories of the mine, the lowest of which is 145 fathoms under
ground. The vein, however, descends much further, to an unknown depth,
and its horizontal extent has likewise not yet been measured.
As the limestone in which the ores are imbedded does not form a solid
compact mass, but is of a loose nature, most of the galleries had, from
the very beginning of the mining operations, to be artificially propped.
Until the end of the last century wooden beams were chiefly used for
this purpose—a construction which frequently gave rise to fearful fires.
Thus on March 16, 1803, the workmen saw a thick smoke issuing from
several of the deepest galleries. It rose higher and higher, and spread
through the upper galleries of the mine. No fire was to be seen, no
sound of flames was to be heard, yet there could be no doubt that the
mine was burning. Some of the workmen boldly undertook to descend to the
scene of the fire, but in vain; they were obliged to flee before their
enemy, for the smoke was not only dense and suffocating, but so
impregnated with poisonous vapours that no living being could exist
within its reach. An attempt was now made to smother the fire by
shutting out the air. All the galleries were blocked as near as possible
to the supposed seat of the fire, as well as the two shafts which led to
the upper world. The mine remained thus closed during five weeks, but to
no purpose; for when it was reopened, the fire burst forth more
furiously than before. The flames now howled fearfully from the bottom
of the pit, and the mercurial and sulphurous fumes which rose from it
threatened instant death to anyone who should be rash enough to approach
them. The director of the mine now resolved to flood the works as a last
resource against the ravages of fire. A river was turned into the
perpendicular shaft, and ran during two days and three nights into the
pit. On the first day there was no perceptible effect, but on the
second—whether it were that the vapours produced by the meeting of the
antagonistic elements were striving for an outlet, or that new
inflammable gases had been formed—a most terrific explosion took place,
which made the whole mountain tremble as if shaken by an earthquake. The
huts close to the opening of the shaft were rent to pieces, the stone
houses at the foot or on the slopes of the hill fell in with a
tremendous crash, and the inhabitants of Idria, fancying the day of
judgment had arrived, fled in terror to the hills.
In the mine itself the explosion was afterwards found to have torn up
the galleries, to have burst the vaulted roofs, and to have hurled away
the stairs. But the victory was now won. The vapour gradually drew off,
and after a few weeks it was possible once more to descend into the pit.
Two full years, however, passed before the water was fully pumped out
into the Idriza, where it poisoned all the fishes, with the exception of
the eels, who, it seems, are proof against everything except roasting or
boiling. Even after all the water had been removed, it was still found
impossible to work in the mines, partly from the heat, but chiefly on
account of the venomous fumes, which soon produced all the symptoms of
mercurial disease.
In order to stimulate almost superhuman exertions, an exorbitant salary
was offered to all those who should venture to explore the most
dangerous passages, and gather the quicksilver, which in some places had
collected in considerable masses. But many paid for their greed with
their lives, and for many months afterwards the air remained so noxious
that the ordinary mining works could not possibly be carried on. To
prevent similar accidents for the future, and also on account of the
increasing scarcity of wood, the galleries have since then been walled
with stone; but when we consider that the whole length of the
subterranean passages amounts to no less than fifty miles, we cannot
wonder that many of them are still propped with wood, and that as
recently as 1846 fire raged in the mine, which was again quenched by
putting part of it under water.
The stone galleries are vaulted, and of a masterly construction, seven
feet high and six feet broad. The cost is less than one would suppose,
as the progress of the mining operations furnishes the necessary
materials.
The temperature in many galleries is equal to that of a conservatory;
and if a floral hall, bathed in light and filled with delicious odours,
is felt to be disagreeably hot, the warmth of the air is naturally far
more intolerable in dismal excavations, where the workman pursues his
laborious task by the weak glimmering of a lamp, and in an atmosphere
full of deadly vapours.
Here, as in Almaden, a premature old age is the lot of the unhappy
miners, who while young tremble like old men. Yet some attain a
tolerably good old age, and he who reaches his forty-fifth year with
trembling limbs is said to get accustomed to the effects of the poison,
and may then live, or rather vegetate, till sixty or seventy.
Scarcely any animals live in the mines of Idria. Even spiders cannot
long resist the noxious atmosphere. Rats, however, formerly existed
there in considerable numbers, but have almost entirely disappeared
since the last fire, which proved too much even for them. In some parts
of the mine the mercury is inclosed in the clay-slate in extremely fine
globules, so as scarcely to be visible to the naked eye; but on removing
the ore many of them fall out and collect on the floor, in larger drops
or small pools, which are carefully gathered in leather pouches or bags.
By far the greatest part of the mercury of Idria, however, is combined
with sulphur, and is obtained by distilling the ore in vast furnaces.
It may easily be imagined that the carriage of a liquid body of the
weight of mercury requires the greatest care. The old mode of packing,
still partly in use, is in sheep-skins, which can acquire the necessary
firmness only by being tanned with alum, and are attentively examined
before being used. After having been filled, the sack is first tried on
a wooden table, and, having successfully stood the ordeal of severe
pressing and punching, is enclosed in a second skin. Two of these
packages, each containing forty-one pounds and a few ounces, are then
placed in a small cask, and three of these in a square box. But as, in
spite of all these precautions, the sacks will sometimes burst, the
mercury is now frequently transported in large iron bottles, the
stoppers of which are firmly screwed down by means of a machine invented
for the purpose. All the quicksilver packed up in this manner is sent to
Trieste, and thence chiefly to England, while that which is destined for
Vienna and Germany is exported in sacks.
In the years 1856, 1857, and 1858, 4,570, 7,178, and 4,331 hundredweight
of mercury were produced in Idria, and sold at an average price of one
hundred florins. In 1850 mercury was worth two hundred and fifty florins
the hundredweight, and thus we see how detrimental the competition of
California has been to the Austrian treasury, which, in its chronic
state of atrophy, is little able to bear any diminution of revenue.
A great part of the produce of the mines—about 1,000 hundredweight—is
manufactured into cinnabar in Idria, which supplies almost all Europe
with this splendid red colouring matter. All the other European
quicksilver veins, in Tyrol, Bohemia, Hungary, and the Bavarian
Palatinate, are utterly insignificant when compared with Almaden and
Idria, as none of them produce more than a few hundredweight.
But even Almaden and Idria have lost much of their former importance
since the discovery of the rich mines of New Almaden in California,
which in 1865 yielded 4,000 hundredweight of mercury. As the uses of
mercury are few, the falling off in price has been the consequence. But
the greater cheapness of mercury has had a most favourable influence on
the production of silver in Mexico, Peru, Bolivia, &c., as many of the
poorer ores can now be profitably worked; and thus California, which by
its gold placers threatened to disturb the relative value of the two
precious metals, has, by promoting at the same time the production of
silver, largely helped to maintain the former equilibrium and to relieve
the fears of many political economists.
It is a remarkable circumstance that, while Europe has for the last
three centuries received almost all its silver from America, Mexico and
Peru were all the time dependent upon the old world for the mercury
without which Potosi and Guanaxuato would have been comparatively
unproductive. Quicksilver, it is true, had been found here and there,
but the only mine of importance was that of Huancavelica in Peru, the
discovery of which in the year 1567 is attributed to the Indian Gonzalo
Navincopa, though, according to Humboldt, it was already known to the
Incas, who made use of cinnabar to paint their cheeks, as Roman senators
and Athenian archons had done before them. Here, at a height surpassing
that of the Peak of Teneriffe by 1,500 feet, from 4,000 to 6,000 cwt. of
quicksilver were annually obtained, until the folly of a director ruined
the chief mine. Ever since 1780 Huancavelica had with difficulty
supplied the growing wants of the Peruvian silver mines, for at a
greater depth the ore was found to be mixed with sulphuret of arsenic,
which greatly deteriorated its quality. As the lode forms an enormous
mass, strong pillars had been left standing to support the roof, and
these props the above-mentioned director had the improvident temerity to
remove, in order to increase the produce of the mine. What anyone with a
little experience or common-sense might have foreseen, took place. The
rock, deprived of its supports, gave way, the roof fell in with a
tremendous crash, and the mine was ruined—a memorable warning against
the greed which, snapping at a shadow, loses the substance.
CHAPTER XXXI.
THE NEW METALS.
Zinc—The Ores, but not the Metal, known to the Ancients—Rapid Increase
of its Production—Chief Zinc-producing Countries—Platinum—Antimony—
Bismuth—Cobalt and Nickel—Wolfram—Arsenic—Chrome—Manganese—Cadmium—
Titanium—Molybdenum—Aluminium—Aluminium Bronze—Magnesium—Sodium—
Palladium—Rhodium—Thallium.
The metals known to the ancients were either such as occur in a native
state and whose lustre must attract even the attention of the savage, or
such as are easily extracted from their ores by the simple agency of
fire and carbon, and consequently require no complicated metallurgic
treatment. Their number is limited to the seven substances described in
the preceding chapters; but the art of the modern chemist has greatly
extended our knowledge of metals, and revealed to us the existence of no
less that fifty-six of these elementary bodies.
Some have been found to lurk under the obscure disguise of alkaline and
earthy matters, such as clay and chalk, magnesia and sand, soda and
potash; others have been discovered in the water of mineral springs, or
under the brilliant mask of precious stones. Most of these were unknown
before the beginning of the present century, nor can there be a doubt
that future researches will make us acquainted with many metals whose
existence is still a secret to mankind.
Most of these new metals are as yet mere objects of curiosity, either
from their rarity or the great difficulty and cost of their production;
but some of them are already of considerable use, and within the last
fifty years zinc has obtained a rank among the most important products
of the mineral world. Calamine, the chief ore which provides us with
this metal, was indeed known to the ancients, who by smelting it with
copper ores obtained an alloy similar to our brass;[61] but the metal
itself seems to have been first discovered by the famous alchemist
Bombastus Paracelsus, who flourished towards the end of the fifteenth
century. Zinc, however, remained unnoticed as a useful metal until the
year 1805, when Hobson and Sylvester’s discovery that it is malleable at
a temperature of 300° F., and can then be worked to any shape with great
facility, caused it to replace lead for many purposes, in which its
hardness and other valuable qualities render it superior. As it is very
easily extended into thin sheets, and combines the advantages of
lightness, salubrity, and durability, it is frequently used for the
roofing of houses and for the sheathing of ships. Many of our domestic
utensils, particularly those which serve for the holding of liquids, are
now made of zinc. Large quantities are moulded into architectural
ornaments; and the splendid white colour of the oxide of zinc has made
it a triumphant rival of ceruse, or white-lead. To provide for so many
uses, the production of zinc has in a short time made strides without a
parallel in the history of metals. While before 1808 from 150 to 200
tons sufficed for the annual consumption of Europe, more than 110,000
tons are now required, so that in little more than half a century the
demand has increased more than five hundred times, and a metal
previously almost unnoticed is now produced in masses worth several
millions of pounds.
Footnote 61:
A coin of Nero, analysed by Arthur Phillips, was found to consist of
81·07 per cent. copper, 1·06 tin, and 17·73 zinc; another, of Hadrian,
of 85·78 copper, 1·19 tin, 1·81 lead, 6·43 zinc, and 0·74 iron.
The chief zinc-producing countries of Europe are Prussia and Belgium.
The Prussian mines, which in 1866 yielded 1,204,419 hundredweight, or
about 60,000 tons, are situated in Silesia, Westphalia, and the Rhenish
provinces. In the same year Belgium produced 35,500 tons, chiefly from
the mines of the Vieille Montagne, near Aix-la-Chapelle, where calamine
occurs in a large mass, imbedded in chalk, and is worked like an open
quarry.
In England calamine is, next to galena, the most important ore obtained
from the Derbyshire mines, and of late years large quantities of blende
or sulphuret of zinc—an ore which, on account of the special
difficulties offered by its treatment, had hitherto been neglected—are
likewise furnished by the Isle of Man, Denbighshire, Flintshire, and
Cornwall.
In 1864 our entire production of zinc amounted to no more than 4,040
tons; but since that period it has been considerably increased by the
importation of immense quantities of Sardinian, Swedish, and Spanish
ores, which are for the most part reduced in the works of Messrs.
Vivian, at Swansea.
For many years the United States depended upon Europe for their whole
supply of zinc; but as nature seems to have denied none of her mineral
riches to the great republic, the discovery of immense deposits of
calamine and blende in the state of Tennessee has enabled them to
compete successfully with foreign produce, and the works of Leehigh and
Lasalle now furnish a large proportion of the zinc consumed in the
country.
Platinum, the heaviest body in nature, was first discovered by the
Spaniards, in the gold mines of Darien, probably in the first half of
the sixteenth century;[62] but as it remained infusible in the strongest
heat, and no method was known for purifying its ore, in which it is
remarkably combined with six or even seven other metals, it continued
for a long time to be a mere object of curiosity. In 1772 Count
Sickingen discovered that it can be welded like iron when urged to a
white heat, and first succeeded in producing platinum wire and platinum
leaves. A few years after the celebrated Swedish chemist, Bergmann,
isolated it from the metallic substances associated with its ore, and
proved it to be a peculiar metal.
Footnote 62:
Kopp, ‘Geschichte der Chemie,’ vol. iv. p.221.
Platinum is found in almost all the auriferous districts of the globe,
but generally in such small quantities as not to be worth the
collecting. Kuschwa Goroblagodat and Nishne-Tagilsk, in the Ural,
furnish annually about eight hundred hundredweight, which is nearly ten
times the amount from Brazil, Columbia, St. Domingo, and Borneo. But, in
spite of this scanty production, its discovery must be considered as one
of the most important conquests which science has made in the material
world, as its perfect infusibility, its hardness, its unalterability by
air and water, and its property of withstanding the action of the most
corrosive simple acids, render it an invaluable material for the
fabrication of various chemical vessels, without whose assistance many
important discoveries could not possibly have been made. To the
manufacturers of sulphuric acid large retorts of platinum are
indispensable for concentrating this highly corrosive fluid, which
devours every other metallic vase with which it comes in contact. The
price of platinum is intermediate between that of gold and silver.
The ores of Antimony played a great part in the labours of the
alchemists, but the metal is first mentioned in the works of Basilius
Valentinus, who flourished during the second half of the fifteenth
century. It is used chiefly in several important alloys. Combined with
lead it constitutes type-metal, and united with lead and tin it is
employed for making Britannia metal, and the plates on which music is
engraved. Nearly all the antimony of commerce is furnished by the grey
sulphuret (stibnite), which occurs in Hungary, Saxony, South America,
and Australia. Though Cornwall produces a considerable quantity of
antimonial ore, our chief supply is derived from Singapore, the emporium
of the various mines of Borneo and other parts of the Malayan
Archipelago.
The grey antimony ore was employed by the ancients for colouring the
hair and the eyebrows, and for staining the upper and under edges of the
eyelids—a practice still in use among Oriental nations for the purpose
of increasing the apparent size of the eye. According to Dioscorides, it
was prepared for this purpose by inclosing it in a lump of dough, and
then burning it in the coals till it was reduced to a cinder. It was
then extinguished with milk and wine, and again placed upon coals and
blown until it was ignited, after which the heat was discontinued, lest,
as Pliny says, ‘_plumbum fiat_’—it become lead. It hence appears that
the metal antimony was occasionally seen by the ancients, though not
distinguished from lead.
Bismuth, a metal of a dull silver-white colour, inclining to red, is
first mentioned in the writings of the alchemists of the Middle Ages. It
is almost exclusively furnished by the mines of Schneeberg in Saxony,
where it is generally found in a native state. On account of its great
fusibility and brittleness it is seldom used alone; but associated with
other metals it forms several valuable alloys.
In the Middle Ages the Saxon and Bohemian miners believed all those ores
from which, in spite of their promising appearance, they were unable to
extract a useful metal, to be a work of the gnomes mocking the industry
of man. Some of these ores they called Kobold—an opprobrious name given
to these evil subterranean spirits, who were supposed to be of dwarfish
stature and intense ugliness; others Nickel—a name probably of the same
meaning as our old Nick. The progress of metallurgic industry has fully
exculpated the gnomes of all evil intentions, for the last century
succeeded in extracting the metals Cobalt and Nickel from those
rebellious ores. Cobalt, though as yet but rarely employed, gives
promise of some future importance, as it appears to be extremely
tenacious. A wire made of pure cobalt will carry nearly double the
weight that an iron wire of the same thickness will do.
The cobalt ores, which impart a magnificent blue colour to glass, have
lost much of their importance as pigments since the discovery of
artificial ultramarine, while the nickel ores which usually accompany
them, and were formerly thrown away as rubbish, have become valuable,
since the metal which they contain has found some important uses. The
small coin of Belgium and Switzerland is now made of nickel instead of
copper, and large quantities are employed in the fabrication of German
silver, or Argentine plate, an alloy of copper, nickel, and zinc, which,
from its hardness and brilliant white colour, furnishes an excellent
material for tablespoons and forks. Both the nickel and cobalt ores are
produced chiefly by Sweden, Norway, and Germany; our own mines furnish
but insignificant quantities. In the United States the Camden works (New
Jersey) now produce nickel at the rate of 150,000 pounds a year.
Tungsten, a metal discovered in 1783 by two Spanish chemists, the
brothers Juan and Fausto d’Elhujar, in a black mineral called wolfram,
which frequently occurs along with tin ores in Cornwall (where it is
known under the names of cal, or callen, and gossan), Saxony, Austria,
&c., is in its isolated state a mere object of scientific curiosity, but
when melted with cast steel or even with iron only, in the proportion of
from two to five per cent., it produces a steel which is very hard and
fine-grained, and for tenacity and density is superior to any other
steel made. Hence wolfram-steel, which is now coming extensively into
use in Germany, makes the best knives and razors; but, unfortunately,
the rarity and high price of wolfram confine its production within
narrow limits. Several of the tungstates, or salts of tungsten, are used
as pigments; and the tungstate of soda has the highly valuable property
of rendering fabrics uninflammable, and thus furnishes a means for
preventing the accidents which constantly occur from the burning of
ladies’ dresses.
Albert the Great, a famous alchemist of the thirteenth century, is
supposed to have been the discoverer of Arsenic, a tin-white metal,
which, however, soon loses its brilliancy when exposed to the air, and
turns black. From its poisonous qualities it is only used in some
unimportant alloys which serve for the manufacture of insignificant
articles, such as buttons or buckles. Some of its ores and combinations,
which, from their lively yellow, green, and red colour, would otherwise
have been valuable pigments, are likewise for the same reason seldom
used. A great number of copper, nickel, lead, cobalt, zinc, and iron
ores contain some arsenic; but this dangerous substance is obtained
chiefly from the common arsenical pyrites (Mispickel—sulphuret of iron
and arsenic), which occurs in Cornwall and Devonshire. The whole supply
of arsenical ores amounted in 1866 to about 2,610 tons, of which England
and Prussia furnished the greater part.
The metal Uranium, discovered in 1789 by the celebrated Klaproth, in a
black heavy mineral, called Pechblende (pitch-blende), occurring in the
mines of the Erzgebirge, is not used as such, but is very valuable in
porcelain-painting, as it affords a beautiful orange colour in the
enamelling fire, and a black colour in that in which the porcelain is
baked. A laboratory has been opened at Joachimsthal, where the ore is
converted into uranate of soda for this purpose.
Chrome, like cobalt, is used chiefly as a pigment. Several of its salts
are splendid yellow colouring matters, and its oxide imparts the finest
green tints to porcelain. The metal itself, which was discovered by
Vauquelin in 1797, is, as yet, an object of interest only to the
chemist, but may one day become important, as in its pure state it is
very hard, unalterable by air and water, and even less fusible than
platina. Most of its ores belong to the rarer minerals, and but one,
chrome-iron, occurs in sufficient abundance for industrial purposes. It
is found in Hungary, in Norway (which annually exports about 16,000 tons
to Hamburg and Holland), in Siberia, and in large quantities in Maryland
and Pennsylvania. The ore employed in England is obtained mostly from
Baltimore, Drontheim, and the Shetland Isles, and amounts to about 2,000
tons annually.
Manganese is likewise a metal which has not yet left the domain of the
laboratory, but some of its ores are of considerable and increasing
importance. The grey and black oxides of manganese are largely used for
the manufacture of the chloride of lime, a substance well known for its
bleaching properties. They also serve in the fabrication of flint-glass,
as a means for correcting the green tinge which it is apt to derive from
iron, and are employed in the manufacture of various kinds of steel. The
ores of manganese are chiefly provided by the mines of Nassau, which in
1864 yielded 14,460 tons, and of Huelva in Spain, which furnished 24,430
tons in 1865. Our Cornish mines likewise produce considerable
quantities, but are still far from being able to supply the wants of our
colossal industry, which, in 1866, required the importation of no less
than 48,700 tons of oxide of manganese from foreign countries.
Cadmium, which accompanies most of the zinc ores, was discovered by
Stromeyer in 1818. Its sulphuret affords a fine yellow pigment; but the
metal itself, which has the colour and lustre of tin, and is very
fusible and ductile, has no commercial value.
Rutile, a red-brown mineral, occurring in small quantities in the Alps,
Norway, and many other localities, where it is generally found in
crystals, imbedded in quartz, was found by Klaproth, in 1795, to be the
oxide of a peculiar metal which, according to the old fashion of giving
mythological names to new planets and metals, obtained the name of
Titanium. The metal, which has a copper-red colour, has not hitherto
been applied to use; but rutile is employed as a yellow colour in
painting porcelain, and also for giving the requisite tint to artificial
teeth.
Like Titanium, the metal Molybdenum, discovered by Hjelm in 1782, is as
yet interesting only in a scientific point of view; but one of its salts
is used by the cotton-printers as a valuable colouring matter, and
another is indispensable as a re-agent in many chemical researches. Thus
more than one of the modern metals has already become an important
object to the porcelain-painter or the dyer.
Aluminium, the metal which Sir H. Davy discovered in clay or alumina,
and of which the purest native oxides are the varieties of corundum
(oriental ruby, sapphire, &c.), has of late become of technical
importance, and though the cost of its production is very great, as a
pound of aluminium is worth about 4_l._, yet it already serves for many
purposes. Its silvery lustre and perfect unalterability by atmospherical
influences render it an excellent material for objects of art and
ornament, and from its low specific gravity (2-56⁄100) it makes
excellent tubes for telescopes and opera-glasses, which when composed of
any other metal are of a fatiguing weight. Even culinary vases have
already been made of aluminium, for, besides its perfect innocuousness,
it cools very slowly when heated, and greasy substances do not adhere to
it. Its high price is the only obstacle which has hitherto limited its
uses. With copper it forms an alloy (aluminium-bronze) discovered by Dr.
John Percy, which possesses the hardness, tenacity, and malleability of
iron without its liability to rust, and consequently has already found
numerous applications. The beautiful gold colour of this alloy makes it
a valuable material for the fabrication of the vases and ornaments used
in Catholic churches, and a recent decree of the Pope has authorised its
employment for this purpose.
Magnesium, the metallic basis of magnesia, a native earth widely
disseminated in the mineral kingdom, and forming a constituent part of
whole mountain chains, had ever since its discovery by Sir Humphry Davy
been a mere object of curiosity, when a few years ago, Mr. Sonstadt, an
English chemist, succeeded in producing it in larger quantities. Its
silvery brilliancy, hardness, and ductility, its low specific gravity,
and unalterability by air and water, are qualities which will probably
lead to an extensive employment when a cheaper method of production
shall have been discovered; but even now it has found a highly
interesting use. It is so easily inflammable that a wire of considerable
thickness can be ignited in the flame of a candle, and the light evolved
by the combustion is of almost solar intensity. In lighthouses it serves
to guide the mariner in his course; it lights up the obscurest recesses
of stalactital caverns, and with its assistance the photographer no
longer depends upon the sun, and reveals to us the hidden paintings and
sculptures of rock-tombs and temples as distinctly as if they were
exposed to the light of day.
Sodium, the metallic basis of soda, was discovered by Sir Humphry Davy
in 1807. It is lighter than water, and white and lustrous as silver; but
exposure to air almost immediately converts it into soda. Thus it can
never become directly useful, like aluminium or magnesium; but being
indispensable for reducing the ores of these two metals, it renders
important indirect services, and is consequently produced in
considerable quantities.
Palladium, one of the hardest and heaviest of metals, is of a steel grey
colour, passing into silver white. Its alloy with silver, which has the
valuable property of not tarnishing in air, is eminently fitted for the
manufacture of delicate scientific instruments. The Wollaston medal,
given by the Geological Society, is, in honour of its discoverer, made
of palladium, which is considerably dearer than gold.
In 1804, the same eminent philosopher discovered another metal in native
platina, to which he gave the name of Rhodium. Mixed with steel in the
proportion of one to fifty, rhodium produces an excellent metal for
making the sharpest cutting instruments, and a mixture of equal parts of
rhodium and steel makes the best telescopic mirrors, as it is not liable
to be tarnished. It is also employed for making the unalterable nibs of
the so-called rhodium pens.
Thallium, though one of the newest metals, as it was discovered by Mr.
Crookes as recently as 1861, already bids fair to render some important
services. It imparts to optical glasses a considerable density and
dispersive power, and should no other use be found for it, this alone
would render it a valuable acquisition.
Such is the brief history of those new metals which have already found a
useful employment in the industrial arts. It throws a vivid light upon
the rapid progress of modern chemistry, for the very existence of most
of them was undreamt of at the beginning of the present century, and
their discovery could be attained only by an amount of analytical
knowledge beyond the scope of any previous age. On witnessing these
triumphs of science we may well ask where they will end, and when the
goal will be reached beyond which it will be impossible for the human
intellect to penetrate?
CHAPTER XXXII.
COAL.
The Age of Coal—Plants of the Carboniferous Age—Hugh Miller’s
Description of a Coal Forest—Vast Time required for the Formation of
the Coal-fields—Derangements and Dislocations—Faults—Their
Disadvantages and Advantages—Bituminous Coals—Anthracites—Our Black
Diamonds—Advantageous Position of our Coal Mines—The South Welsh Coal-
field—Great Central and Manchester Coal-fields—The Whitehaven Basin
and the Dudley Area—Newcastle and Durham Coal-fields—Costly Winnings—A
Ball in a Coal-pit—Submarine Coal Mines—Newcastle View from Tynemouth
Priory—Hewers—Cutting Machines—Putters—Onsetters— Shifters—Trapper
Boys—George Stephenson—Rise of Coal Production—Probable Duration of
our Supply—Prussian Coal Mines—Belgian—Coal Mines in various other
countries—Maunch Chunck.
The history of the primitive races of mankind, as far as we are able to
trace it in the few relics that have survived their existence, shows us
that an age of stone was followed by one of bronze, which in its turn
was succeeded by one of iron. The Golden Age has probably never existed
but in the fancy of poets who sought in the land of dreams a
compensation for the deficiencies of the real world; and there can be no
doubt that, despite California and Australia, our own times are as far
from realising the pleasing vision as any before them.
But a title to which they have a better claim is founded upon the vast
use of the mineral fuel without which the glorious inventions of Watt
and Stephenson would have been comparatively vain; and whoever has
attentively examined the foundations of our industry, our commerce, our
wealth, and our civilisation will hardly deny that we live in what may
justly be termed the Age of Coal.
This mineral, the importance of which in the political economy of the
leading nations of the globe can hardly be overrated, is also one of
surpassing interest in a geological point of view, for the history of
its formation is one of the great marvels of the subterranean world.
[Illustration: PECOPTERIS ADIANTOIDES.]
[Illustration: SPHENOPTERIS AFFINIS.]
The plants whose growth and decay originally furnished the materials of
which our black coal[63] is composed, flourished in that far distant
period when as yet no bird or mammalian quadruped had made its
appearance, when even the gigantic Ichthyosaurus was not yet born, and
the progress of organic life had not advanced beyond the creation of
some uncouth reptiles or strangely formed fishes. From the vast space of
time which separates us from the carboniferous age, it may easily be
imagined that the state of the vegetable world was then extremely
different from that now prevailing. The vegetable remains which
constitute coal have generally been so transformed as to afford no trace
of their original texture; yet the distinct plants found here and there
preserved in the mass, and which amount to about five hundred species,
plainly bear the character of a swampy vegetation, and show that they
must have grown in submerged, or at least extremely humid, situations.
They consist chiefly of ferns, of Lepidodendra, allied to the club-
mosses of the present day, of a few coniferous trees, the woody
structure of some of them showing that they were related to the
Araucarian division of pines, more than to any of our common European
firs; of some large ‘horsetails,’ and of Sigillariæ and Calamites, that
seem to have been distinct from all tribes of now existing plants.
Scanty as are these relics of an extinct world, they yet allow the fancy
to reconstruct the forests of which they formed a part, and to wander
through those dismal woods where generations after generations of
arborescent ferns and moor-plants flourished and decayed for the use of
beings that were to appear millions of years later upon the stage of
life.
Footnote 63:
Lignite, or brown coal, is of more modern origin.
[Illustration: LEPIDODENDRON ELEGANS.]
[Illustration: ASTEROPHYLLITES COMOSA.]
[Illustration: SIGILLARIA OCULATA.]
[Illustration: CALAMITES NODOSUS.]
The following description by Hugh Miller will assist our fancy in
roaming among the primeval thickets from which coal was formed: ‘We have
before us a low shore, covered with a dense vegetation. Huge trees of
wonderful form stand out far into the water. There seems no intervening
beach. A thick hedge of reeds, tall as the masts of pinnaces, runs along
the deeper bays, like water-flags at the edge of a lake. A river of vast
volume comes rolling from the interior, darkening the water for leagues
with its slime and mud, and bearing with it to the open sea reeds and
ferns and cones of the pine, and immense floats of leaves, and now and
then some bulky tree undermined and uprooted by the current. We near the
coast, and now enter the opening of the stream. A scarce penetrable
phalanx of reeds, that attain to the height and wellnigh to the bulk of
forest trees, is ranged on either hand. The bright and glossy stems seem
rodded like Gothic columns; the pointed leaves stand out green at every
joint, tier above tier, each tier resembling a coronal wreath, or an
ancient crown with the rays turned outwards, and we see atop what may be
either large spikes or catkins. What strange forms of vegetable life
appear in the forest behind! Can that be a club-moss that raises its
slender height for more than fifty feet from the soil? Or can these tall
palm-like trees be actually ferns, and these spreading branches mere
fronds? And then these gigantic reeds! are they not mere varieties of
the common horsetail of our bogs and marshes, magnified some sixty or a
hundred times? Have we arrived at some such country as the continent
visited by Gulliver, in which he found thickets of weeds and grass tall
as woods of twenty years’ growth, and lost himself amid a forest of corn
fifty feet in height? The lesser vegetation of our own country, its
reeds, mosses, and ferns, seems here as if viewed through a microscope,
the dwarfs have sprung up into giants, and yet there appears to be no
proportional increase in size among what are unequivocally its trees.
Yonder is a group of what seem to be pines—tall and bulky, ’tis true,
but neither taller nor bulkier than the pines of Norway and America.
There is an amazing luxuriance of growth all around us. Scarce can the
current make way through the thickets of aquatic plants that rise thick
from the muddy bottom; and though the sunshine falls bright on the upper
boughs of the tangled forest beyond, not a ray penetrates the more than
twilight gloom that broods over the marshy platform below. The rank
steam of decaying vegetation forms a thick blue haze, that partially
obscures the underwood. Deadly lakes of carbonic acid gas have
accumulated in the hollows; there is a silence all around, uninterrupted
save by the sudden splash of some reptile fish that has risen to the
surface in pursuit of its prey, or when a sudden breeze stirs the hot
air, and shakes the fronds of the giant ferns, or the catkins of the
reeds. The wide continent before us is a continent devoid of animal
life, save that its pools and rivers abound in fish and mollusca, and
that millions and tens of millions of the infusory tribes swarm in the
bogs and marshes. Here and there, too, an insect of strange form
flutters among the leaves. It is more than probable that no creature
furnished with lungs of the more perfect construction could have
breathed the atmosphere of this early period and have lived.’
As coal seams have been discovered as far to the north as Greenland,
Melville Island, and Spitzbergen, where now no trees will grow, it has
been inferred that, in the primeval ages which witnessed their birth, a
tropical climate must have reigned over the whole surface of the earth;
but the vegetation of arborescent ferns does not necessarily imply a
very warm climate, as such plants are found to flourish in New Zealand,
together with many conifers and club-mosses, so that a forest in that
temperate country may make a nearer approach to the carboniferous
vegetation than any other now existing on the globe. So much is certain,
that a very different distribution of sea and land must in those times
have mitigated the severity of the Arctic winter, or, perhaps, as
Professor Oswald Heer conjectures, our solar system may then have rolled
through a space more densely clustered with stars, whose radiant heat
gave to our earth the advantage of a mild climate, even at the poles.
The space of time required for the formation of the coal-fields is as
immeasurable as the distance that separates us from Sirius. We know by
experience how thin the sheet of humus is which the annual leaf-fall of
our trees, or the yearly decay of our moor-plants, leaves behind, and
how many decenniums must elapse before one single inch of solid mould is
formed. But there are many coal strata eight, ten, or even forty or
fifty feet thick; and if we consider besides the mighty pressure of the
superincumbent rocks which store them in the smallest compass, we cannot
possibly doubt that _one_ such stratum must have required thousands of
years for its formation. Our wonder increases when we reflect that in
many _coal-measures_ (the series of beds intimately associated with the
seams of coal) no less than a hundred thick and thin seams of coal
alternate with layers of sandstone and shale, so that the reckoning
would swell to millions were we able to fathom the ages of their
successive growth.
It may well be asked how such vast masses of vegetable origin, which
required the sun’s light for their formation, came thus to be incased in
stone thousands of feet beneath the surface of the earth? More than one
theory has been advanced to solve this difficult problem, which can
hardly be explained in any other manner than by a general, slowly
progressing subsidence of the humid lowlands, alternating with periods
of rest. Fancy a wide delta land, similar to Egypt or the Netherlands,
covered with luxuriant forests, whose spoils, accumulating where they
fall, form in the course of centuries a thick stratum of vegetable
matter. This land then sinks, suddenly or gradually, under water, many a
fathom deep, and remains there perhaps for ten thousand years, till a
vast deposit is formed of sandstone and shale, brought down from the
highlands by the rivers that come rolling from the interior, the
pressure of which, aided by water, converts the stratum of wood into
coal. By this deposit the bottom is gradually filled up, and the bay
again converted into marsh or meadow, upon which again vegetation
flourishes for a thousand years till the materials of a second bed of
coal are collected. A third submergence takes place, rocky strata are
again deposited, the water again shoals into land capable of bearing
plants, a third period of forests commences, and continues till the mass
of vegetable matter destined to form a new bed of coal is accumulated.
It is unnecessary to pursue the series any further; let it suffice to
say that in this manner coal followed upon sand, or sand upon coal, till
in the carboniferous basin of Nova Scotia, for instance, a vertical
subsidence of three miles was gradually filled up by the waste swept
down from the higher lands, or by the accumulation of vegetable matter.
Great as are these changes of level, they do not indicate any more
considerable or violent perturbations than those which take place at the
present day, either from earthquakes or from slow oscillations of the
soil. Large areas in the Pacific and elsewhere are known to be actually
subsiding at the rate of three or four feet in the century, and when
measured on the scale of geological time, the depression which sunk the
first carboniferous forests of South Wales or Nova Scotia to the depth
of ten or twenty thousand feet, probably proceeded at the same slow
rate. Adding to these vast epochs of gradual subsidence the long periods
of rest which intervened between them, it is perhaps no exaggeration to
affirm that several millions of years may have been required for the
formation of a coal-field such as that of Saarbrücken or South Wales.
The fossil remains inclosed in the various layers of the carboniferous
beds alone suffice to prove the immensity of time required for their
accumulation, for the species of ferns or lycopods imbedded in the lower
seams of a coal-field are found gradually to disappear in the higher
ones, while new species are continually appearing on rising in the
series, until, finally, the plants of the older seams have completely
made way for newer forms. Thus the coal formation has, during the vast
ages of its growth, changed more than once the aspect of its flora, and
the plants which flourished in its youth had long since disappeared from
the earth when it approached its end.
[Illustration:
COAL-BEDS RENDERED AVAILABLE BY ELEVATION.
_a_ _b_ _c_, shafts. A B C, coal-beds.
]
Although all coal-fields must have originally been formed in horizontal
or slightly undulating situations, yet in many cases they have undergone
enormous derangements or dislocations from subsequent terrestrial
changes; and to this circumstance is mainly due their utility to man.
Had they been permitted to remain in their primitive _geological_
position, we probably should never have enjoyed the benefit of the coal,
because it would have been too deep for our reach. We might have known
it to be there, but it would have been beyond our power to pierce a mile
or two into the earth. But, by a wonderful and merciful providence, the
oscillations to which the earth-rind is subject, have frequently
upheaved them enormously out of their original positions; and the
elevated portions having often been denuded by water, large patches of
coal have thus been rendered available to man.
The various subterranean changes which have acted upon the coal-fields
during the course of unnumbered ages have not only raised or sunk, but
frequently dislocated, contorted, ruptured, or broken them up in a most
extraordinary manner. In the coal-field near Mons, in Belgium, for
instance, a vast lateral pressure has curved the strata again and again,
and even folded them four or five times into zigzag bendings, so that on
sinking a shaft the same continuous layer of coal is cut through several
times.
[Illustration: SECTION OF COAL-FIELD SOUTH OF MALMESBURY.]
1. Old red sandstone.
2. Mountain limestone.
3. Millstone grit.
4. Coal seams.
5. Coarse sandstone.
6. New red sandstone.
7. Lias.
8. Inferior oolite.
9. Great oolite.
10. Corn brash and
forest marl.