The authentic history of tin-mining in Cornwall begins with the year 1156. It is not mentioned in Domesday, and probably the Conqueror was as ignorant that tin was to be found there as were the Romans. In the year above given the tin mines are mentioned in the Pipe Rolls. In 1198 appears a letter from the Warden of the Stannaries to the Justiciar. In 1156 most of the tin was raised on Dartmoor, but the output now began to rise rapidly. In 1201 King John issued a charter to the Stannaries. In 1305 the Cornish Stannaries were in part dissociated from those in Devon.

As already stated, in the beds of the valleys running down from the central ridge are deposits of tin, brought there from the lodes degraded by weather and flood in the central spinal ridge. The specific gravity of the tin ore is 6.8, and as the water rolled away from the heights, it deposited the tin that it had brought away with it. "The ores of tin," wrote Pryce in 1776, "are shode and stream ... scattered to some distance from the parent lode, and consisting of pebbly and smoothly angular stones of various sizes, from half an ounce to some pounds in weight. Stream tin is the same as shode but smaller in size and arenaceous."

King Edward Mine

King Edward Mine, Camborne

Polwhele describes an early stream work disclosed about a century ago. The ore was of the purest kind and contained two-thirds metal. The pebbles from which the metal was extracted were in size from sand-like grains to that of a small egg. The depth of the primeval bed was 20 ft. This appeared to have been worked at a remote period, and before iron tools were employed, as large pickaxes of oak, holm, and box were found there. But archaeological research at the period when he wrote was carried on in such a haphazard way that we cannot trust the reports then made, and it is quite possible that the workings were comparatively late, possibly of Mediaeval times.

All the early work was in stream tin. The Cornish tin had this disadvantage—that it was not pure like the Dartmoor tin, but was so associated with sulphur that after smelting it had to undergo a second process, and that a delicate one. It had to be "roasted," to get rid of the sulphur, for only thus could the tin be made available. Associated with sulphur it is brittle. We may well doubt whether in early times the double process was understood. Moreover, we know that when we have the first notices of tin in the west, it was Dartmoor and not Cornwall which rendered the largest supply.

Shaft-mining did not come in before 1450, when the stream tin was exhausted. The use of the adit cannot be traced back beyond the beginning of the seventeenth century. The only way of draining the mines was by rag and chain pumps, each consisting of an endless chain, broadened at intervals by leathern bindings, to fit snugly into a pipe from 12 to 22 ft. long, worked by a windlass at the surface. To drain a mine of great depth a series of these pumps was necessary.

When hydraulic draining-engines were first employed is not known, but even so late as the close of the eighteenth century some mines were drained by the rag and chain pump worked by 36 men.

Up to the sixteenth century, wooden shovels and picks are known to have been employed, and shovels were merely iron-shod. There is in the British Museum a MS. calendar of Haroldstone in S. Wales, of the early sixteenth century, in which are representations of the works of the months, and in it the labourers in the fields are shown as using wooden spades shod with metal.

German mining was carried on upon better principles than the English, and Sir Francis Godolphin sent for an experienced German engineer to instruct the miners of Godolphin and Tregonning in the superior systems employed in Saxony. It was then only that the hydraulic stamps were introduced.

In 1742 one steam-engine only was found in the county; but speedily after came a great advance. Savery and Newcomen brought in their steam pump; that of Newcomen was introduced at Chasewater in 1777.

Notwithstanding that the methods of descent into the mines by a series of long ladders had been superseded by the man-engine, first introduced in 1842, it was a long time before the old ladders at different successive stages were abandoned.

Owing to the introduction of tin from the Straits Settlements, where it is found in the condition of stream tin and can be easily worked, the tin mining in Cornwall, necessitating real mining and the following of lodes, has proved unremunerative and has been abandoned, and now but few mines are worked for the metal. Another cause has fatally affected Cornish mining—the fraudulent practice of the promoters of the mines. It was no uncommon practice for the "captains," when a rich lode was struck, to cover it up, and follow false lodes, till the investors in the venture lost heart and refused to advance more money, when the captains would carry on the work in the real lode, if they could raise the capital, but this they often failed to do, the mine having fallen into discredit, or the water having broken in.

But if tin mining be practically dead in Cornwall, another industry has risen with leaps and bounds. It is that of the china-clay and china-stone, employed in the manufacture of porcelain, in the sizing of paper and of cotton materials, in the manufacture of alum, etc. The glazed paper so largely employed in our illustrated papers is made up largely with china-clay. Some years ago the Italian government employed this paper for its official documents, but found that after a few years under the influence of damp weather the records had dissolved into a lump of clay.

China Clay Quarries

China Clay Quarries

China-clay consists of decomposed felspar, quartz and white mica. In 1817 the amount shipped for manufacturing pottery was comparatively small, but of late years it has grown, and employs over 3000 persons. The china-clay is the same as the Chinese Kaolin; its value was discovered by a Plymouth Quaker, Mr Cookworthy, in 1745.

Porcelain was introduced into Europe from the East in 1518, when it acquired the name of China. For a long time it was supposed that the kaolin or fine white clay of which it is composed, was found only in the Celestial Empire, and specimens of this brought to Europe fetched a high price. At the beginning of the eighteenth century it was discovered in Saxony in an odd way. A merchant named Schnerr, being on a journey, was struck with the whiteness of some clay near Schneeburg, and collecting some of it used it for powdering his wig. It succeeded, but had this disadvantage, that wigs dressed with this new powder were very heavy. An apothecary named BÖtcher noticed the increased weight of the wig, analysed the powder, and discovered that it was identical with Chinese kaolin. He began to make Dresden China in 1709, and the process was carried on with the greatest secrecy, the exportation of the earth being forbidden under heavy penalties.

In 1748 Cookworthy discovered kaolin on Tregonning Hill, more was found at Boconnoc, and Cookworthy and Thomas Pett began to make china in 1768. At present St Austell is the great seat of this industry, and the produce is shipped at Charlestown and Polmear.

Delabole Slate Quarries

Delabole Slate Quarries

The important slate-quarries of the Duchy, of which the Delabole quarry is the most renowned, have already been mentioned.

At Calstock and Gunnislake a few years ago there were numerous miners engaged in the manufacture of arsenic from the waste product of the abandoned copper mines. But now this has become an extinct industry.

Shipping Slate, Port Gavin

Shipping Slate, Port Gavin

Wulfram or tungsten, a metal used as an alloy for hardening steel, was also a waste product from the tin mines, but it is now utilised. At St Ives, pitchblende is now being worked for radium.