arrested by the magnetick nidus of Goffan, when it is variously depofited, Stalactical, Guttatim, Machacada, or otherwise, as we may judge from the preffure, form, and fituation of it when found.

The Stalactical, is generally of a braffy colour; and o is the blistered buttony Ore, which is protuberant in a femi-circular form, occafioned by its defcent guttatim, into a soft and yielding bed of clay. But the vitriolick solution that forms malleable Copper, is the strongest that can be obtained; therefore it is the more readily attracted by the ferruginous particles of the Goffan through which it percolates, and in very little time, affumes the place and form of its magnet, in quantity, cæteris paribus, as the folution and the nidus are more or lefs abundant. Being thus fituated and circumftanced, it likewife forms the Filagree, Laced, Machacada Copper of Alonzo Barba; which is the precipitation of Copper on the laminæ of Goffan, interfecting in all directions, and leaving unequal cavities, of various angles between the fepta : the ftructure, therefore, is very cellular, and makes it look like copper lace that has been burnt.

These three forts, however, are very fcarce; and more of them are faved for the cabinets of the curious, than are melted in the furnace. Green Copper Ore is likewise very rare in Cornwall; and is feldom fo pure, as to be taken for a gem of the Turkois kind. Blue Copper is feldom met with, and in efteem only among the curious.

Gray Copper Ore is one of the richest forts in this county. It looks like a kind of Lead; cuts with a knife, to a very fmooth face; and will produce the greateft quantity of Metal, of any Copper Ore.

Black Copper Ore, of a bluish black, is also very rich. This is either folid, or fandy, being mixed with a light tender Crystal and fandy Mundick. It is fo light, that it will not bear the ufual dreffing by water; but is generally griddled out and put to the pile for fale, as it rifes from the Mine. Being in this condition, it partakes of Mundick, Goffan, Earth, and Crystal, fo largely, that the intrinfick value of the Ore will be carried off with it. It is faid, that formerly feveral thousand pounds worth of this Ore was thus washed into the rivers, and difcharged into the north fea from the old Pool Mine. This kind of Ore in the Lode is oftentimes fo fair, that it may be raised

and

and dreffed fit for smelting, at the rate of a fhilling out of the pound, in the price it fells for; nay I have known an instance of its being done for ten pence. In this cafe, the end or ftool

of the vein will run of itself, like fand, against the workman with the use of his fhovel only. This Ore generally lies fhallow; and seventy years ago, when Copper was not fearched for and little known among us, the Tinners threw it into the rivers as refuse, by the name of Poder, which fignifies duft, Mundick, or wafte. After it became well known, and was wrought for fale, it feldom exceeded 3 10s. ton for feveral years, while there were but one or two purchasers.

Red Copper Ore is rather scarce, but it is valuable. There is a kind of red, fteel grained, goffany Ore, that looks very rich, and is worth from 14 to 20 ton, according as it is impregnated with Gal or Iron, which renders it harsh and ftubborn for fmelting. But of all Copper Ores, that which goes by the name of Peacock Ore, far furpaffes the reft for beauty and elegance of tint, while it is new and fresh; for after it has been long exposed to the falts of the atmosphere, its beautiful colour fades away. The interior of this is yellow.

Of yellow Copper Ore, I have obferved four forts in general. The first is found fhallow among black Ore, small, or not in large rocks; and it can be freely scraped into a yellow duft of a rich appearance. The second is the fine gold coloured flakey Ore, that is rich to the eye and in the crucible; its real value may be from £12 to 15 ton: it is this kind of Ore which fhoots into diftinct and regular tetrahedrons, geometrically defined a triangular pyramid of four equilateral triangles: they are always fmall, distinct, regular, and of the highest polish; are very common, and as commonly overlooked by the fuperficial obferver. The third is a perfect brass coloured Ore, which rifes in great quantities, and is reckoned the best colour of any for its continuance in the Mine: when this comes up in plenty, the Miners please themselves with the fight of it for that reason, although the value may be not more than from £7 to £10 This coloured Ore feldom rifes before the vein is funk fifty fathoms deep, or at least not in great heaps; the richer or more inconftant Ores being fuperincumbent. But the fourth and deepest Copper Ore is of a pale yellow, pretty much corrupted with Mundick, and of an inferior price, being from £4 to £6 ton. The fuperior quantity, however, recompences for its quality and charges of dreffing; for it is not

ton.

uncommon

uncommon for fome of thofe Lodes to produce from 300 to 400 tons of Ore monthly. It is very probable, that the ancients meant this kind of Copper Ore, when they speak of their Native Brafs. Our Miners exprefs their sense of the folidity and richness of fuch a Lode, by saying, "She is as folid as a Brass and Sir John Pettus, in his Fleta Miner. fays, "Yellow Copper, for diftinction, is properly called Brafs in the Stone."

pan:"

The immature poor Ores of Copper, are conftituted of Crystal, (Spar) Earth, Vitriol, Sulphur, Lead, Black Jack, Mundick, &c. and are vulgarly distinguished by the names of Goffany, Sparry, (Crystal) Mundicky, Peachy, Flookany Lodes; according as thefe appearances may predominate in the Stone or Mineral Ore, of which in their proper places. Some authors call the Ore of Copper, Cadmia Nativa; and yellow, or mundicky Copper Ore, they call Pyrites Erofus, and fometimes Chalcitis. The green fpume of Copper, like Verdigrease, they term Chryfocolla, or Native Borax; and the blue coloured Spume, they call Cæruleum Montanum; and fometimes both by the names of Ærugo Æris, or Copper Ochres. (Pliny, Hill, Da Cofta.)

Copper is to be found in most countries: of late years, however, Cornwall has produced its portion equal to most of them, to the amount of thirty thousand tons of Ore in the year 1770; and for variety of colours none can exceed us.

By Chymistry we know, that alkaline falts produce a blue colour with Copper, which is changed into green, as foon as any acid is added; and from thence the reason is obvious, why

a green colour be found among calcareous Copper Ores,

may

viz. when the vitriolick acid is in the neighbourhood of it. (Engeftrom's notes upon Cronstedt). Thefe menftrua being differently qualified by one another, impart the grey, black, and peacock dyes; but when the menftrua are clear and forcible, they borrow from the Copper, and impart the most piercing tints to precious Stones, making the Lapis Lazuli, the Sapphire, Emerald, Amethyst, &c.

Copper Ores are vaftly different from Tin Ores; for the former are always vifible in the Stone, though much inferior in quantity of Metal to the latter, except fome of the grey Copper Öres, which contain as much Metal, as the beft of the Tin. By what we have heard of the Ores of other countries, we

believe,

believe, that those which we have in Cornwall are much poorer in kind, than any where else: perhaps, in other countries, the poor veins are neglected. This poverty of our Ores, as well as the waste they are fo abundantly mixed with, is the fource of infinite profit to the laborious inhabitants; as both fexes of all ages are employed in dreffing and cleanfing them fo as to be fit for fale.

Iron, Ferrum; Steel, Chalybs; is called Mars, and has fo great a conformity with Copper, as not to be easily separated when foldered together; whence arifes that reciprocal friendship, which the poets feign between Mars and Venus.

It is fometimes, but very rarely, found native, and is the product of moft countries. Cornwall has likewife her Lodes of Iron, fome of them rich and near the furface, but they are generally small; and the charcoal for smelting of it is scarce; at least it is more profitably used for melting of Stream Tin. These reasons, with our vicinity to fundry feaport towns, where all forts of Iron are imported at firft hand, and our natural attachment to Tin and Copper Mining, have occafioned a neglect among us of working our Iron Lodes.

Iron Ore is vulgarly called Ruddle, Reddeng, Oker or Ochre, according to its varieties of colour: the reddeft fort of it is thought to be a kind of Red Chalk. Some is ftalactical, and called Brush Ore; and fome is fine, foft, and earthy, and called Smit. But those which are mistaken by many for diftinct forts of Foffils, are the Hæmatites, or Bloodstone; the Magnes, or Loadstone; the Smiris, or Emery; and Magnefia, or Manganefe, &c. all which are separate fpecies of Iron Ore.

It is the hardest, drieft, and moft difficult to fmelt, of all Metals, and will ignite a long time before it will flow; yet it is the only Ore that strikes fire with Flint. Malleable Iron is very difficult to be melted, without the addition of Antimony, or fome other fulphureous fubftance; it will not unite with Quickfilver in any wife; but is eafily corroded and acted upon by every fort of acid menftrua, and by moft if not all forts of Salts. This Metal, in the first smelting, is called Caft Iron, which is brittle; but is perfected by annealing it in the fire, and then by hammering of it, though gently at firft, when it becomes malleable. Steel is made of the best and pureft Iron, by cementing it with the hoofs and horns of beafts, and fuch excrefcences, S which

which contain a volatile animal Salt; and being fo cemented, they quench it in water, whereby its pores are fo greatly conftringed, that it immediately grows fo hard as to acquire the properties of Steel.

Of all the fubftances concurring to form the terreftrial globe, Iron seems to have the greatest ubiquity; as it is well known to enter into the compofition of Earth, Stone, Plants, and Animals, fo truly, that from the afhes of either you may visibly and fenfibly perceive its existence, even so as to be discovered in various fecretions from human blood, in milk, urine, fat, &c. as may be proved by drawing a Loadstone (whofe property it is to attract Iron only) over their calx, afhes, or refiduum, when the Iron particles will be drawn out of them, and adhere to the Magnet.

Iron is the most useful to human life: it is our defence and fecurity; and no arts or manufactories could exift without it. Navigation, trade, and commerce, would be at a ftand; and even the art of discovering other Mines and Metals, could not be practifed without it: fo that this, which is confidered as the bafeft of Metals, is indifpenfably neceflary for all the various ufes of mankind. Befides the innumerable kinds of inftruments made of it, it furnishes excellent remedies in many diseases: by its figure and gravity with the human blood, it becomes a deobftruent and restorative in cold and relaxed temperaments; but in full and fanguine habits, it is inflamatory and dangerous, unless preceded by venefection and other evacuations.

Tin, Stannum; Jupiter. in the Chaldee fignifies flime, mud, or dirt; and when the Phenicians came into Cornwall, and faw this Metal in its ancient flimy ftate, they called it, "The Mud:" from thence the name, Tin, (in Cornu-british Stean, in Latin Stannum) has proceeded, and is ftill continued. Some of the ancients called it Plumbum Album, White Lead, to distinguish it, perhaps, from common Lead. It was by them called White Lead, from its colour and purity; but they did not know it to be, radically, another Metal. We find no Latin name in authors for the Ore of Tin; probably, because the ancients were unacquainted with it as a Metal characteristically diftinct from Lead. Neither do the Tinners or Miners call it Tin Ore; for they give it the name of Tin-stuff, as it rises out of the earth; and they distinguish it by feveral incidents which happen often to it, either from the Ores, or crude Minerals

intermixing