hereabouts. I before mentioned the sudden disappearance of the limestone to the northward, occasioned by its rapid dip, which introduces in its room gritstone, and shale, or shiver. Of these substances the latter is nearly of a black colour, varying in quality and texture; of extreme hardness in its stratum, but soon shivering when exposed to the atmosphere; sometimes impregnated with vitriol and iron; sometimes saturated with carbonic acid; and sometimes containing petroleum. The limestone mountain, called Tre-Mountain, to the south of the shiver, is full of marine exuvia; enchrini, entrochi, screws, high-waved cockles, &c. as well as quartz crystal, and elastic bitumen attached to the limestone. It contains also that singular calcareous substance, peculiar to this spot, called Blue-John, found in detached masses of irregular forms and different sizes, from that of an apple to nearly a ton in weight; and worked by the manufacturers at Castleton, Buxton, Derby, and other places, into beautiful pillars, vases, and other ornamental forms. The miners say, Nature intended it for lead, but that accident has made it what it is. The scarcity of it, at present (for it appears to be nearly exhausted) has raised its price on the spot to 20l. per ton. You are not to imagine, however, that all the elegant articles sold in the shop for Blue John are worked

from this material in its genuine unadulterated state; the dealers in it, even amongst the mountains of Derbyshire, exhibit as much dexterity in adulterating and altering it as the most ingenious artizan in Duke's-place or the Minories could do. The article, when dug out, is of various colours, according as it is more or less tinged with mineral; and some of it of so deep a blue as to approach nearly to black. In order to render this saleable, the manufacturer exposes it to a gentle heat for a short time, and having thus warmed it through, places it in a much stronger for about half an hour, when it is drawn out, and exhibits those rich and resplendent purple tints which put to shame the lustre of the famous Tyrian dye. Great care, however, is requisite in this process; for should the mass continue too long exposed to the fire, every colour would be discharged, and the whole reduced to an opaque white. Exclusive of this trick, the workmen have another mode of recommending their ware by artificial beauty. The masses frequently are found imperfect, that is, indented with holes, where this happens to be case, a quantity of lead is melted and poured into the place, and afterwards being cut and polished with the spar, assumes the curious appearance of having been naturally combined with it.

Our next visit was to the very ancient mine of Odin, about a mile to the west of Castleton, at the foot of the Tre mountain, employing about one hundred and forty labourers, men, women, and children. It consists of two levels, running horizontally under the mountain; the upper, a cartgate, by which the ore is brought from the mine; the lower one, a water-level, to drain it from the works. They penetrate the mountain to more than a mile from the entrance, and are ventilated by shafts sunk into them from above, at the distance of every thirty yards. At the mouth, the level is not more than a fathom and a quarter from the surface of the land; but at the further extremity, above one hundred and fifty. It belongs to several proprietors, and makes great returns. The ore produced here is called potter's ore; its veins usually intersecting the limestone stratum at right angles, which veins are composed of cawk, kevil, and calcareous spar, and sometimes blende, barytes, mangenese, sulphate of iron, native oxyde of zinc, carbonate of lead, combined with lead ore, separated at various depths by the toad-stone, which here stratifies alternately with the limestone. The ore is different in quality, the best yielding about three ounces of silver to the ton weight of lead. The system by which the mine

property we are speaking of is regulated, being somewhat complicated, as well as singular, I must

give you an account of it in the intelligible words of Dr. Aikin.

"There are numerous and various regulations respecting the rights of miners, and the dues payable for the ores in different parts of the mining country. The principal tract containing lead is called the king's-field. Under this denomination nearly the whole wapentake of Wirksworth is comprised, as well as part of the high Peak. The mineral duties of the king's-field have been from time immemorial lett on lease; the present farmer of those on the high Peak is the Duke of Devonshire, and of those in the wapentake of Wirks-> worth is Mr. Rolles. They have each a steward and bar-masters in the districts they hold of the crown. The steward presides as judge in the barmote courts, and, with twenty-four jurymen, determines all disputes respecting the working of mines. The courts are held twice a year; those of the high Peak at Money-Ash, and those of the wapentake at Wirksworth. The principal office of the bar-masters is putting miners in possession of the veins they have discovered, and collecting the proportion of ore due to the lessee. When a miner has found a new vein of ore in the king's

field, provided it be not in an orchard, garden, or high-road, he may obtain an exclusive right to it on application to the bar-master. The method of giving possession is in the presence of two jurymen, marking out, in a pipe or rake work, two meares of ground, each containing twenty-nine yards; and in a flat work, fourteen yards square. But if a miner neglect to avail himself of his discovery within a limited time, he may be deprived of the vein of which he has received possession, and the bar-master may dispose of it to another adventurer. As to the other part of the bar-master's office, that of superintending the measurement of the ore and taking the dues of the lessee or lord of the manor, it is attended with some difficulty, from the variety of the claims, which differ greatly in different places. In general a thirteenth of the ore is due in king's-field, but a twenty-fifth only is taken; besides this there is a due for tithe. In mines that are private property, such tolls are paid as the parties agree on.

“The miner having satisfied the several claims proceeds to dispose of his ore to the merchant or smelter. There are four denominations of ore; the largest and best sort is called bing; the next in size, and almost equal in quality, is called pesey; the third is smitham, which passes through the