FOOTNOTES:
[84] The Phœnicians traded upon the western coasts of Cornwall, for at least six hundred years before the birth of our Saviour, and that for the sake of Tin;—so that the antiquity of our tin trade has been established upon mercantile principles for not less than twenty-four centuries. But in the earlier ages this metal was all procured from Stream Works, the method of working mines not having been known and practised for more than seven hundred years.
[85] In the year 1822, the produce of the Copper mines in Cornwall amounted to 106,723 tons of ore, which produced 9,331 tons in Copper, and £676,285 in money. Whereas the quantity of Tin Ore raised did not exceed 20,000 tons.
[86] The Saxon Miners formerly regarded Cobalt in the same way. They considered it so troublesome when they found it among other ores, that a prayer was used in the German Church, that God would preserve Miners from Cobalt, and from Spirits.
[87] Lead is principally found in cross courses, or north and south veins. Pentire Glaze, near Padstow, which has lately produced the finest cabinet specimens of Carbonate of Lead, ever found in this country; and Huel Golding in Perranzabuloe, are the principal mines in which the Lead occurs in cross courses. Lately, however, East and West Lodes of Lead have been discovered in the Parish of Newlyn, by Sir C. Hawkins, in draining a marsh. They are about two feet wide. Besides the Lead and a little quartz, they consist entirely of Clay; neither Copper nor Tin have been seen in them. The Lead yields about Sixty Ounces of Silver per Ton.
[88] Cobalt. Huel Sparnon Tin and Copper Mine in the Parish of Redruth, is the only mine in the county that ever produced any considerable quantity of Cobalt; one fragment raised from it weighed 1333 lbs.
[89] Silver. In the Copper Lode of Huel Ann, there occurred a distinct vein of black and grey Silver ore, with Native Silver, from two to five inches wide with a wall of Quartz, on each side. It was however very short. See Mr. Carne's paper on the Silver Mines of Cornwall, Transactions of the Royal Geological Society of Cornwall, vol. i. p. 118.
[90] Only one Lode in Cornwall has, however, been found of this size, and that only for the length of 20 fathoms in Relistian. In Nangiles the lode is, in some parts, 30 feet wide.
[91] As the Counting House of Dolcoath has been determined to be 360 feet above the level of the sea, the mine extends 1050 feet below it; which is probably deeper under the sea level than any mine in the globe.
[92] Clay-slate is provincially called Killas; and Porphyry is known by the name of Elvan.
[93] For a full account of this subject, the reader must consult Mr. Carne's laborious paper, "On the Veins of Cornwall," in the 2nd Volume of the Transactions of the Royal Geological Society of Cornwall.
[94] We must refer the reader to a Paper, "On the Veins of Cornwall," by W. Phillips, Esq., published in the 2nd vol. of the Transactions of the London Geological Society; and also to a Paper, "On the relative Age of Veins," by Joseph Carne, Esq. in the 2nd vol. of the Cornish Transactions.
[95] We shall pass over, as being too absurd to require any serious refutation, the former belief in the power of the Virgula Divinatoria to discover Lodes. A power less poetical but not less fabulous then the story of the Virga Fatalis that conducted Æneas to the Shades.
[96] Grass is the technical name for the surface on all occasions.
[97] The great Copper Mine, called Crennis, was discovered by some casual observers in the cliff.
[98] From Aditus, a passage?
[99] The application of this machine in the county is estimated as saving the labour of 10,000 men; whilst the powers of the different steam-engines are considered as at least equivalent to 40,000 more.
[100] See Dr. Forbes's Paper "On the Temperature of Mines," in the second volume of the Transactions of the Cornish Society.
[101] The annual cost of gunpowder, used in the mines of the county, amounts to more than thirty thousand pounds.
[102] Transactions of the Royal Geological Society of Cornwall, vol. 2, page 162.
[103] The quantity of water discharged by the pumps from many of the Cornish mines is very considerable; thus Huel Abraham discharges from the depth of 1440 feet, about 2,092,320 gallons every 24 hours; Dolcoath, from nearly the same depth, 535,173 gallons in the same time; and Huel Vor, from the depth of 950 feet, 1,692,660 gallons.
[104] See Dr. Forbes's paper on the temperature of mines, in the Transactions of the Royal Geological Society of Cornwall, vol. 2, p. 208; also on the temperature of mines, by R. W. Fox, Esq. ibid. p. 14, and a paper on the same subject by M. P. Moyle, Esq. p. 404.
[105] Crennis Copper Mine returned a clear profit to the adventurers of £84,000 in one year; and Huel Alfred, during the last period of its working, yielded very nearly £130,000, after having defrayed every necessary expense. The adventurers in Huel Vor have lately gained £10,000 in three months. But, on the contrary, how numerous are the losses, not perhaps corresponding in magnitude, in any individual mine, to the gains which have been above stated. In North Downs as much as £90,000 were lost, but this is a rare instance.
[106] The consumption of such articles in a great mine far exceeds any estimate which a person unacquainted with mining operations could possibly imagine. In Huel Vor, no less than Three thousand pounds of candles are consumed in a month, and about Three thousand five hundred pounds of Gunpowder.
[107] Before the invention of the Stamping Mill, the Tin was pulverised in a kind of mortar, called a Crazing Mill; one of which ancient machines is still in the possession of Mr. Williams of Scorrier House.
[108] This process might be more generally employed in Cornwall with much advantage. The green coloured water which so frequently issues from the adits, might be made to yield a considerable portion of Copper, if it were properly received in pits, and submitted to the action of Iron.
[109] Stream Tin, on account of its purity, is alone capable of furnishing the grain tin, employed principally by dyers.
[110] The principal Stream works are in the parishes of Lanlivery, Luxilian, St. Blazy, St. Austel, St. Mewan, St. Stephens, and St. Columb. The greatest Stream work in the county is at Carnon, about half-way between Truro and Penrhyn; but there is scarcely a valley in which the operation has not been conducted on a small scale.
[111] In the Ordnance Map of Cornwall, a spot marked "the Gold Mine" is noticed, near Liskeard. This name serves only to commemorate one of the many ruinous speculations into which the inhabitants of this County have repeatedly fallen, from a want of mineralogical knowledge. A mass of Pyrites having been discovered in this place, its brilliancy induced a belief that it was Gold, in consequence of which workings were immediately commenced, and the sanguine adventurers, urged forward no doubt by those who derived an interest from the undertaking, could not be convinced of their error, until the complete ruin of their fortunes obliged them to abandon every hope.
[112] This is the deepest Adit in the country; its mouth or extremity being nearly on a level with the water in one of the creeks of Falmouth Harbour, into which it empties itself. Taking into calculation its various windings, through the numerous mines which it relieves of water, it may be said to be not less than twenty-four miles in length.
[113] Menabilly is situated about four miles west of Fowey, on an eminence at a short distance from the sea.
[114] We have been told that this has been arranged by Mr. Aikin, according to the different modifications of its crystalline form, as they are described by Mr. William Phillips in his elaborate paper published in the 2nd Vol. of the Transactions of the London Geological Society.
[115] See an interesting account of this mineral in a notice entitled "Contributions towards a knowledge of the Geological History of Wood-Tin, by A. Majendie, Esq." in the first volume of the Transactions of the Royal Geological Society of Cornwall.
[116] Since the first edition of this work was printed, the mineral has been found at Saint Michael's Mount, and, by Dr. Boase, amongst a pile of ore which was supposed to come from Botallack.
[117] In one of which is to be seen the Muriate of Tin, as first noticed by the late Reverend William Gregor.
[118] The following are the names of the respectable dealers to whom we recommend the mineralogist to apply,—At Truro, Tregoning, Mudge, and Heard;—at Redruth, Bennett; at Gwenap, Michell;—at Saint Agnes, Argall;—at Falmouth, Trathan;—and at Penzance, Jacobs, the latter of whom has generally a great variety of Saint Just minerals on sale.
[119] Opie was a parish apprentice to a person of the name of Wheeler, a house carpenter, in the village of Saint Agnes; Dr. Walcott, better known by his poetical appellation of Peter Pindar, having been struck, during his occasional visits to the village, by some rude sketches in chalk which were shewn him as the productions of this poor lad, invited him to his house at Truro, supplied him with the necessary materials, and enabled him to set up as an itinerant portrait painter, from which station he rose to be Professor of Painting to the Royal Academy.
[120] A highly interesting paper "On the decomposition of the Granite Tors of Cornwall," by this geologist, is published in the second volume of the Transactions of the Geological Society of London.
[121] This may be distinctly seen in the granitic rocks in the islands of Scilly; and in the Gritstone in the park of the late Sir Joseph Banks, in the parish of Ashover in Derbyshire.
[122] The only chemical difference between Cleavelandite and Felspar is, that about 12 per cent. of Potass in the latter is replaced by an equal quantity of Soda in the former. The earthy ingredients in both minerals are the same, and exist in similar proportions. The primary form of each is a doubly oblique prism, but the two prisms differ so essentially from each other in the measurement of their angles, that the substances are easily distinguished from each other by the Goniometer.