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.’
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.