There is something grand in the progress of a mechanical process, from
its commencement to its termination. Especially is this the case in the
production of metals, nearly every step in the course of which is marked
by the hard, unyielding spirit of _vis inertiae_ on the one hand, and
the tremendous power of intelligence, machinery, and manual dexterity on
the other.
Take, for example, the progress of a mass of tin from Botallack.
Watch yonder stalwart miner at work, deep in the bowels of the mine.
Slowly, with powerful blows, he bores a hole in the hard rock. After
one, two, or three hours of incessant toil, it is ready for the powder.
It is charged; the match is applied; the man takes shelter behind a
projection; the mass is rent from its ancient bed, and the miner goes
off to lunch while the smoke is clearing away. He returns to his work
at length, coughing, and rubbing his eyes, for smoke still lingers
there, unable, it would seem, to find its way out; and no wonder, lost
as it is in intricate ramifications at the depth of about one thousand
five hundred feet below the green grass! He finds but a small piece of
ore--perhaps it is twice the size of his head, it may be much larger,
but, in any case, it is an apparently poor return for the labour
expended. He adds it, however, to the pile at his side, and when that
is sufficiently large fills a little iron wagon, and sends it up "to
grass" through the shaft, by means of the iron "kibble." Here the large
pieces of ore are broken into smaller ones by a man with a hammer; as
far as the inexperienced eye can distinguish he might be breaking
ordinary stones to repair the road! These are then taken to the
"stamps."
Those who have delicate nerves would do well to keep as far as possible
from the stamps of a tin-mine! Enormous hammers or pounders they are,
with shanks as well as heads of malleable-iron, each weighing, shank and
head together, seven hundredweight. They are fearful things, these
stamps; iron in spirit as well as in body, for they go on for ever--
night and day--wrought by a steam-engine of one hundred horse-power, as
enduring as themselves. The stamps are so arranged as to be
self-feeders, by means of huge wooden troughs with sloping bottoms, into
which the ore is thrown in quantities sufficient to keep them constantly
at work without requiring much or constant attendance. Small streams of
water trickle over the ore to keep it slowly sliding down towards the
jaws, where the stamps thunder up and down alternately. A dread power
of pounding have they, truly; and woe be to the toe that should chance
to get beneath them!
The rock they have to deal with is, as we have said, uncommonly hard,
and it enters the insatiable mouth of the stamps about the size of a
man's fist, on the average, but it comes out from these iron jaws so
exceeding fine as to be incapable of thickening the stream of
reddish-yellow water that carries it away. The colour of the stream is
the result of iron, with which the tin is mingled.
The particles of tin are indeed set free by the stamps from solid
bondage, but they are so fine as to be scarcely visible, and so
commingled with other substances, such as iron, copper, sulphur,
etcetera, that a tedious process of separation has yet to be undergone
before the bright metal can be seen or handled.
At the present time the stream containing it is poured continuously on
several huge wooden tables. These tables are each slightly raised in
the centre where the stream falls, so that all the water runs off,
leaving the various substances it contains deposited on the table, and
these substances are spread over it regularly, while being deposited, by
revolving washers or brushes.
Tin, being the heaviest of all the ingredients contained in the stream,
falls at once to the bottom, and is therefore, deposited on the head or
centre of the table; iron, being a shade lighter, is found to lodge in a
circle beyond; while all other substances are either spread over the
outer rim or washed entirely away. When the tables are full--that is,
coated with what appears to be an earthy substance up wards of a foot in
depth--the rich tin in the centre is carefully cut out with shovels and
placed in tubs, while the rest is rewashed in order that the tin still
mingled with it may be captured--a process involving much difficulty,
for tin is so very little heavier than iron that the lighter particles
can scarcely be separated even after repeated and careful washings.
In old times the tin was collected in large pits, whence it was
transferred to the hands of balmaidens (or mine-girls) to be washed by
them in wooden troughs called "frames," which somewhat resembled a
billiard table in form. Indeed, the frames are still largely employed
in the mines, but these and the modern table perform exactly the same
office--they wash the refuse from the tin.
Being finally cleansed from all its impurities, our mass of tin bears
more resemblance to brown snuff than to metal. An ignorant man would
suppose it to be an ordinary earthy substance, until he took some of it
in his hand and felt its weight. It contains, however, comparatively
little foreign substance. About seventy per cent of it is pure tin, but
this seventy per cent is still locked up in the tight embrace of thirty
per cent, of refuse, from which nothing but intense fire can set it
free.
At this point in the process, our mass of tin leaves the rough hand of
the miner. In former days it was divided among the shareholders in this
form--each receiving, instead of cash, so many sacks of tin ore,
according to the number of his shares or "doles," and carrying it off on
mule or horse back from the mine, to be smelted where or by whom he
pleased. But whether treated in this way, or, as in the present day,
sold by the manager at the market value, it all comes at last to the
tin-smelter, whose further proceedings we shall now follow, in company
with Oliver and his friend.
The agent of the smelting company--a stout, intelligent man, who
evidently did "knaw tin"--conducted them first to the furnaces, in the
neighbourhood of which were ranged a number of large wooden troughs or
bins, all more or less filled with tin ore. The ore got from different
mines, he said, differed in quality, as well as in the percentage of tin
which it contained. Some had much iron mixed with it, in spite of all
the washings it had undergone; some had a little copper and other
substances; while some was very pure. By mixing the tin of different
mines, better metal could be procured than by simply smelting the
produce of each mine separately. Pointing to one of the bins, about
three yards square, he told them it contained tin worth 1,000 pounds.
There was a large quantity of black sand in one of the bins, which, the
agent said, was got by the process of "streaming." It is the richest
and best kind of tin ore, and used to be procured in large quantities in
Cornwall--especially in ancient times--being found near the surface,
but, as a matter of course, not much of that is to be found now, the
land having been turned over three times in search of it. This black
sand is now imported in large quantities from Singapore.
The agent then conducted his visitors to the testing-house, where he
showed them the process of testing the various qualities of tin ore
offered, to the House for sale. First he weighed out twenty parts of
the ore, which, as we have said, resembled snuff. This, he remarked,
contained about five-sixths of pure tin, the remaining one-sixth being
dross. He mixed it with four parts of fine coal dust, or culm, and
added a little borax--these last ingredients being intended to expedite
the smelting process. This compound was put into a crucible, and
subjected to the intense heat of a small furnace for about twenty
minutes. At the end of that time, the agent seized the crucible with a
pair of tongs, poured the metal into an iron mould, and threw away the
dross. The little mass of tin thus produced was about four inches long,
by half an inch broad, and of a dull bluish-grey colour. It was then
put into an iron ladle and melted, as one would melt lead when about to
cast bullets, but it was particularly noteworthy here, that a very
slight heat was required. To extract the metal from the tin ore, a
fierce heat, long applied, was necessary, but a slight heat, continued
for a few minutes, sufficed to melt the metal. This remelted metal was
poured into a stone mould, where it lay like a bright little pool of
liquid silver. In a few seconds it solidified, retaining its clear
purity in all its parts.
"That," said the agent, "is tin of the very best quality. We sell it
chiefly to dyers, who use it for colouring purposes, and for whom no tin
but the best is of any use. I will now show you two other qualities--
namely, second and inferior."
He went to a small cupboard as he spoke, and took therefrom a small
piece of tin which had already gone through the smelting process in the
crucible above described. Melting this in the ladle, he poured it into
the mould, where it lay for a few moments, quite bright and pure, but
the instant it solidified, a slight dimness clouded its centre.
"That," explained the agent, "is caused by a little copper which they
have failed to extract from the tin. Such tin would not do for the
dyers, but it is good for the tin-plate makers, who, by dipping thin
sheets of iron into molten tin, produce the well-known tin-plates of
which our pot-lids and pans, etcetera, are manufactured. This last bit,
gentlemen," he added, taking a third piece of tin from the cupboard, "is
our worst quality."
Having melted it, he poured it into the mould, where it assumed a dull,
half-solid appearance, as if it were a liquid only half frozen--or, if
you prefer it, a solid in a half molten state.
"This is only fit to mix with copper and make brass," said the agent,
throwing down the mould. "We test the tin ore twice--once to find out
the quantity of metal it contains, and again to ascertain its quality.
The latter process you have seen--the former is just the same, with this
difference, that I am much more careful in weighing, measuring,
etcetera. Every particle of dross I would have collected and carefully
separated from any metal it might contain; the whole should then have
been reweighed, and its reduction in the smelting process ascertained.
Thus, if twenty parts had been the weight of tin ore, the result might
perhaps have been fourteen parts of metal and six parts of dross. And
now, gentlemen, having explained to you the testing process, if you will
follow me, I will show you the opening of one of our furnaces. The
smelting-furnace just shows the testing process on a large scale. Into
this furnace, six hours ago," he said, pointing to a brick erection in
the building to which he led them, "we threw a large quantity of tin
ore, mingled with a certain proportion of culm. It is smelted and ready
to be run off now."
Here he gave an order to a sturdy man, who, with brawny arms bared to
the shoulders, stood close at hand. He was begrimed and hairy--like a
very Vulcan.
Seizing an iron poker, Vulcan probed the orifice of the furnace, and
forthwith there ran out a stream of liquid fire, which was caught in an
iron bowl nearly four feet in diameter. The intense heat of this pool
caused the visitors to step back a few paces, and the ruddy glow shone
with a fierce glare on the swart, frowning countenance of Vulcan, who
appeared to take a stern delight in braving it.
Oliver's attention was at once attracted to this man, for he felt
convinced that he had seen his face before, but it was not until he had
taxed his memory for several minutes that the scene of his adventure
with the smugglers near the Land's End flashed upon him, when he at once
recognised him as the man named Joe Tonkin, who had threatened his life
in the cavern. From a peculiar look that the man gave him, he saw that
he also was recognised.
Oliver took no further notice of him at the time, however, but turned to
watch the flow of the molten tin.
When the iron cauldron was almost full, "slag," or molten refuse began
to flow and cover the top of the metal. The hole was immediately
plugged up by Vulcan, and the furnace cleared out for the reception of
another supply of ore. The surface of the tin was now cleared of slag,
after which it was ladled into moulds and allowed to cool. This was the
first process completed; but the tin was still full of impurities, and
had to undergo another melting and stirring in a huge cauldron. This
latter was a severe and protracted operation, which Vulcan performed
with tremendous power and energy.
In reference to this, it may interest the reader to mention a valuable
discovery which was the result of laziness! A man who was employed in a
tin-smelting establishment at this laborious work of stirring the molten
metal in order to purify it, accidentally discovered that a piece of
green wood dropped into it had the effect of causing it to bubble as if
it were boiling. To ease himself of some of his toil, he availed
himself of the discovery, and, by stirring the metal with a piece of
green wood, caused such a commotion that the end in view was
accomplished much more effectually and speedily than by the old process.
The lazy man's plan, we need scarcely add, is now universally adopted.
The last operation was to run the metal into moulds with the smelter's
name on them, and these ingots, being of portable size, were ready for
sale.
While the agent was busily engaged in explaining to Charles Tregarthen
some portions of the work, Oliver stepped aside and accosted Joe Tonkin.
"So, friend," he said, with a smile, "it seems that smuggling is not
your only business?"
"No, sur, it ain't," replied Joe, with a grin. "I'm a
jack-of-all-trades--a smelter, as you do see, an' a miner _also_, when
it suits me."
"I'm glad to hear it, my man, for it gives you a chance of coming in
contact with better men than smugglers--although I'm free to confess
that there _is_ some good among them too. I don't forget that your
comrade Jim Cuttance hauled me out of the sea. Where is he?"
"Don't knaw, sur," replied Tonkin, with an angry frown; "he and I don't
pull well together. We've parted now."
Oliver glanced at the man, and as he observed his stern, proud
expression of face, and his huge, powerful frame, he came to the
conclusion that Cuttance had met a man of equal power and force of
character with himself, and was glad to get rid of him.
"But I have not gi'n up smuggling," added the man, with a smile. "It do
pay pretty well, and is more hearty-like than this sort o' thing."
"I'd advise you to fall back on mining," said Oliver. "It is hard work,
I know, but it is honest labour, and as far as I have seen, there does
not appear to be a more free, hearty, and independent race under the sun
than Cornish miners."
Joe Tonkin shook his head and smiled dubiously.
"You do think so, sur, but you haven't tried it. I don't like it. It
don't suit me, it don't. No, no; there's nothin' like a good boat and
the open sea."
"Things are looking a little better at Botallack just now, Joe," said
Oliver, after a pause. "I'd strongly advise you to try it again."
The man remained silent for a few minutes, then he said,--"Well, Mr
Trembath, I don't mind if I do. I'm tired o' this work, and as my time
is up this very day, I'll go over to-morrow and see 'bout it. There's a
man at Newlyn as I've got somethin' to say to; I'll go see him to-night,
and then--"
"Come along, Oliver," shouted Tregarthen at that moment; "it's time to
go."
Oliver bade Tonkin good-afternoon, and, turning hastily away, followed
his friend.
The two proceeded arm in arm up Market-Jew Street, and turning down
towards the shore, walked briskly along in the direction of the
picturesque fishing village of Newlyn, which lies little more than a
mile to the westward of Penzance.