INDUSTRIES to the dressers' interest either to be lazy, or to be hurried and slipshod in their work, the favourite way was to set the ore to dress in proportion to the price it brought at the smelter's. 1 In the stannaries the tributer paid the land- lord, bounder, and adventurers their respective dues in piles of tin-stone ready for the stamps, and retained the residue. In the copper mines the tributer excavated, raised, and prepared the ore for smelting at his own expense. It was then given over to the adventurers, who disposed of it at the ticketing, and from the cash pro- ceeds paid the workmen according to the rate previously agreed. 2 Another anomaly is ex- emplified by the system of private sampling described by Pryce. ' The takers of tribute pitches in copper are also obliged to mix their ores with those of other pitches, or with the owners' ores, and to sample them according to the will and discretion of the captains, otherwise the parcels of ore would be small, where there may be twenty pitches on tribute in one mine. Before the parcels are mixed together, they take from each a fair sample. The assay master, who buys at the public ticketing or sale a mixed parcel of ore, has these private samples given him, which he assays for zs. 6d. each, with all the judgment and dexterity he is capable of, to make the most of each, and it is a very rare thing for any com- plaint to arise, so expert are they in their business.' 3 ' The use of private samples is this. Although the sundry parcels of ore mixed for sale may appear nearly of one value at sight, yet it must necessarily follow that some difference will arise from the different management in the dressing and other incidental causes. In a mixed parcel of 50 tons A may have 20 of 15 per ton, B 25 of 14 los., and C 5 of 16 per ton, according to private samples, yet the gross 50 tons may sell for 1 5 5/. per ton. Never- theless the amount must be divided among the tributers according to the selling price, subj-ct to regulation by private samples ; in other words, the excess or diminution for what it sells must be proportioned by the produce of the private samples, for if 50 tons sell at 15 5*., the amount is equal to 762 los. Pursuant to the above private samples, A's 20 tons at 15 bring 300 ; B's 25 tons at 14. los. bring 362 los. ; C's 5 tons at 16 bring j8o, a total of j/42 lot., or 20 short, by private sample. This is called a 20 increase.' 3 The method of proportioning this among the tributers, says Pryce, is by the rule of three. 4 ' It is evident,' he continues, ' that if the adventurers were to account to the tributers at the private prices, they would deprive them of 20, of which they ought to have their respective proportions, it being the absolute value for which the copper was sold. It is clear also that by mixing these 1 Pryce, Minerahgia Cornubiensis, 240. 'Ibid. 188. 'Ibid. 190. ' Ibid. 191. three parcels they have altogether brought a better price by 20 than if they had been sold separately.' 5 As in the tin mines, the element of luck in taking pitches, resulting sometimes in leaving the workman half starved, the fact of the system being open to innumerable opportunities for crooked dealing on the part of the miners, and the consequences of the practice of auctioning the tut and tribute pitches to the lowest bidder, resulting too often in a fierce competition for work, which reduces the price paid the miner to a merely nominal sum, 6 are combining gradually to make tribute working a phenomenon of the past. Improvements in copper dressing in the century and a quarter since Pryce wrote, may be summed up in the statement that the various processes which the latter so thoroughly described have been simplified by the application of machinery. The first great improvement effected upon this basis was the substitution of crushing machines for bucking. The first crusher is said to have been erected at Dolcoath by Trevithick in 1 804.' Others were used in the Tavistock district about 1 8 1 4, 8 and in the course of a few years were introduced into all large concerns, 9 under the name of halvan crushers. In every operation common to both, copper dressing has since advanced with that of tin. A distinctive feature in the nineteenth century has been the attention paid to the sizing of the stuff, effected by revolving riddles and sizing wheels, which greatly facilitates subsequent treatment. 9 A further economy was effected by the process known as precipitation. Costar, early in the eighteenth century, had observed at Chacewater, 9 that copper held in solution in mine water might be precipitated by means of iron. Precipitation was tried at Wheal Crofty, and although aban- doned there, was introduced at Cronebane, Wicklow, under the superintendence of a Cornish mine captain. 10 From Ireland it went to Cuba, and in 1854 from Cuba to Cornwall again, where it was applied to the waters of the Gwennap adit. Its practice at present has become uniform throughout the county. The various vicissitudes which the copper mines have suffered since their establishment on a sound basis by the smelting arrangements made with the Swansea companies, have been due not so much to the exhaustion of their lodes as to underselling by newer and richer mining fields. The first conflict was with the enormously rich 5 Pryce, Minerahgia Cornubiensis, 191.
- English, Mining Almanack, i, 1 20- 1 29.
' Worth, Historical Sketch of the Origin and Progress of Mining Skill in Devon and Cornvi. 44. 8 De la Beche, Geology of Cornwall, Devon, and West Somerset, 594. 9 ' Copper Mining in Cornwall,' by Jos. Carne. Trans. Roy. Geol. Soc. ofConttv. iii, 63. 10 Worth, Historical Notes on the Origin and Progress of Mining Skill in Devon and Comw. 44. 569 7 2
