The tin of Cornwall constituted a branch of commerce at a very early period; the Phenicians and Grecians are said to be the first persons who came to Britain to traffic for that article, but how long they enjoyed the advantage cannot be exactly ascertained. On the discovery of the secret that the Phenicians and Grecians had the means of procuring this valuable metal in Britain, the Romans under Cæsar were induced to undertake an invasion. Though they had possession of the mines for a long period, it does not appear they made much progress in working them. During the Saxon government, the tin mines are said to have been altogether neglected, and the subsequent wars with the Danes and antient Britons prevented the possibility of much progress being made in mining concerns. After the Conquest, the mines were of little value to the proprietors, and even in the reign of King John, the product of them was so trivial, that the Tin Farm amounted only to 100 marks, and the King, with whom the right of working the mines solely rested, was so sensible of their low state, that he bestowed some valuable privileges on the county, by relieving it from the arbitrary forest laws, and granting a charter to the tinners, &c.
During the time of Richard, King of the Romans and Earl of Cornwall, the revenue of the tin mines yielded an immense return; at which time many Jews appear to have been employed in working them. Notwithstanding this success, the latter were banished from the kingdom in the 18th year of the reign of Edward I., when the mines again became much neglected. Shortly after a charter was granted (through Edmund, Earl of Cornwall) to the gentlemen of Blackmoor, proprietors of the Seven Tithings, affording the greatest quantities of tin; by which charter, more explicit grants of the privileges of keeping a court of judicature, holding pleas of action, managing and deciding all stannary causes, of holding parliaments at their discretion, and of receiving as their own due and proportion, the toll tin, or one-fifteenth of all tin raised, were defined. At the same time, the right of bounding or dividing tin grounds into separate portions, for the encouragement of searching, appears to have been regulated; by which the labouring tinner, who might discover tin in waste or uncultivated lands, became entitled to a certain interest in the land, upon giving proper notice in the Stannary Court to the proprietor thereof. The bounds limited the particular portions of ground to which the claim was made, and were formed by digging a small pit at each angle, so that a line drawn from each, determined the extent of the claim. This practise still exists, and the bounder is obliged to renew the pits every year, by removing any dust or rubbish that might otherwise hide his land marks.
Carew says, that “this charter had a seal affixed to it, with a pick axe and shovel in saltier.”
In consideration of the privileges granted by this charter, the gentlemen tinners undertook to pay to Edmund and his successors, Earls of Cornwall, the sum of 4s. for every hundred weight of white tin. To secure the payment of that tax, they agreed that all tin should be brought to places appointed by the Prince, and there weighed, coined, and kept till the duties were paid.
In the 33rd of Edward I., this charter was confirmed, and the tinners of Cornwall were made a distinct body from those of Devonshire, having before been accustomed to assemble on Hengston Hill, every seventh or eighth year, to arrange their concerns and property in the mines. The laws and privileges of the Cornish miners were further enlarged in the 15th year of the reign of Edward III., and subsequent acts passed in the reigns of Richard II., and Edward IV., which confirmed the previous privileges, and the tinners divided into four bodies, and placed under the superintendance of one Warden, reserving them an appeal from his decisions, in suits of law and equity to the Duke of Cornwall in council, or should the title be held in abeyance, then to the Crown.
A Vice Warden is appointed by the Lord Warden, to determine all stannary disputes; he also constitutes four Stewards, (one for each precinct) who hold a Stannary Court every three weeks, and decide by juries of six persons, with a right of progressive appeal to the Vice Warden, Lord Warden, and the Lords of the Prince’s Council. The original Stannary Towns were Launceston, Lostwithiel, Truro, and Helston; to these places the miners were obliged to bring their tin every quarter of a year. But in the time of Charles II., Penzance was added for the convenience of the western tinners.
All tin ores are wrought into metal in the county, and are afterwards cast into blocks, weighing from 2½ cwt. to upwards of 3 cwt. each. They cannot be disposed of till assayed by the proper officers, and stamped with the Duchy seal, which bears the arms of Richard, Earl of Cornwall, viz. a lion rampant, gules, crowned or, with a border sable garnished with bezants.
Since the reign of Henry VIII. the coinages have been held quarterly. The average annual produce of the tin mines is about 25,000 blocks, which, exclusive of duties, may be valued at £260,000, and yielding a revenue to the Duchy of Cornwall of about £10,000 annually. The most considerable tin mines now working, are in the neighbourhood of St. Austell, St. Agnes, and Piranzabuloe. The celebrated Polgooth Mine, near the former place, however, has not been worked for upwards of 20 years past.
There are also many other valuable tin mines in the western districts, north-west of Truro.
Besides the mines, there are several stream works in the county, which have yielded immense quantities of tin.