intermixing with or corrupting of it; as Pryany, Peachy, Goffany, or Mundicky Tin-ftuff: or elfe according to the degrees of fineness, or smallness, that it is brought to, by stamping of

powder. Being pulverized fine, wafhed, and cleanfed, it then has the name of Black Tin; and is, therefore, fit to be fmelted into White Tin, or Metal. It does not acquire a real blackness by its pulverization, but is of various colours according to the colour of the stuff with which it is principally mineralized it most commonly, however, partakes of a brownish or dufky liver colour; and obtains the name of Black Tin, in contradiftinction to its metallick colour and properties.

The existence of native Tin remains a doubt among the curious, to this day; but I never heard one reafon advanced, why it cannot exist. Although Tin is the lightest of all Metals, its Ore, when rich, is the heaviest of all metallick Ores; infomuch as fometimes to have a greater fpecifick gravity, than a piece of pure Tin of the fame fize: this is probably occafioned by the abundant quantity of Mundick with which it is combined.

The Ores of Tin may be generally claffed into Shode, Stream, and Bal or Mine Tin. The Shode is disjunct, and scattered to fome declined distance from its parent Lode; and is pebbly, or fmoothly angular, of various fizes, from half an ounce to fome pounds weight. Stream Tin Ore is the fame as Shode, but fmaller fized, arenaceous, and in its ftate, is in the form of fmall pyramids of various planes, very broad at the base, and tapering to a point at the top. In polish and colour, these grains, fo called, are gloffy jet black, refinous, or red, and are the pfeudo garnet, ruby, topaz, &c. The largest fingle grain of Tin that we remember to have seen, is in the poffeffion of Mr. Giddy, Surgeon, in Penzance, which weighs two ounces, four pennyweights, and twenty-two grains. Stream Tin Ore, is the smaller loose particles of the Mineral, detached from the bryle or backs of fundry Lodes, which are fituated on hilly grounds, and carried down from thence by the retiring waters of the diluvium, or floods of subsequent dates, being collected in large bodies or heaps, in the valleys. In the folid rock of the valley, there is no Tin Ore; but immediately upon it, is deposited a layer of Stream Tin of various thickness; perhaps over that, a layer of earth, clay, gravel, &c. and upon that again another stratum of Tin Ore; and so on fucceffively, ftratum fuper ftratum, according to their gravity, and the different periods

periods of their coming thither, to the depth of eighteen feet at a medium in St. Austell Moor. In St. Blazey Moor, at the depth of twenty feet, they have what they call Stream (Tin Ore) about five feet in thickness in the bottom, great part of which had been anciently wrought before Iron tools were known, feveral wooden pick-axes of oak, holm, and box, having been lately found therein. Over this they have a complete ftratum of black mud, fit for burning; on this a ftratum of gravel, very poor in Tin; on this another ftratum of mud; and uppermoft gravel again.

Bal or Mine Tin Ore, frequently rifes very rich; and instances are plenty, where it has been discovered in the richest and purest state imaginable. Under fuch circumstances, it has been carried to the fmelting-house, as it came out of the earth, and the proprietors have received ten parts in twenty of it in Metal, the Imelter having taken to himfelf perhaps one part more for his expence and profit. Polberou in St. Agnes, which belongs to the Donnithorne family, produced great quantities formerly. In the year 1750 it is faid, one rock of Tin from that Mine, weighed 1200 pounds, and produced one half in Metal, clear of all expence to the owner, who gained £100 + diem for fome confiderable time.

I obferve that this kind of rich Tin Ore, which confifts of the blackest grains or Crystals, is ufually found at a moderate depth, or within the day fide of forty fathoms. Grouan Lodes; fo called from their participation of the nature of the adjunct and incumbent ftrata, do most usually produce those very rich Crystals. But a lofty folid unformed Tin Ore, is commonly the production of all kinds of ftrata; and, according to my obfervation, is in itself more independent of any contingent influence. I have feen the fame folid lumps of black and dufky liver coloured Tin Ore arise equally alike in form, colour, and appearance, from Lodes in Grouan, Mourftone, Ironftone, Kellas, or Crystal strata. Goffan never exhibits a rich fhew of Tin Ore; for it is in that nidus more diffeminate and minute. It feldom continues in Goffan, above thirty fathoms from grass. But if we descend from the loftiness of Tin Ore before described, we may find it, although invisible to the inexperienced Miner, very rich and fmall grained; in which pofiture it is scarcely known, but by the exceeding gravity of the Stone in which it is enshrined, and the different colour thereof from the adjacent ftrata. Sometimes it is in blue, gray, black, or brown coloured Lode-ftones,

Lode-ftones, extremely fmall; fometimes veined in the Stones, and branchy throughout the Lode, whereby it may be separated and forted as it rifes, to the faving of much expence in dreffing: in other places it may be priany, peachy, flookany, or mundicky, with which it may be either very prevalent or scanty; but in the latter, and where Copper participates, it must be well burnt before the true value of it can be known.

This Metal seems to be earthy and very fulphureous; almost soft and pliable as Lead, but more white and beautiful. Bend a piece of pure Tin, or bite it hard, and it will give a crashing noife or ftridor; but its purity is beft known by obferving the whiteness or delicacy of its grain, when broke off fhort. Tin, like Lead, is more eafily diffolved in a weak acid menftruum, than in a ftrong one. It may be eafily amalgamated with Quickfilver, and melts almost as readily as Lead; therefore, it will not bear ignition. It is not naturally very fonorous; becomes fo, when properly commixt with Copper. It will not eafily endure the teft by fire; for as foon as the heat becomes violent it affumes the form of a ftubborn afh or calx, which foon lofes its fluidity, and is changed into a powder called Putty; which powder is also made by calcination of Tin, but is reducible into Tin again by melting with a proper flux.

but

Befides its usefulness in utenfils per fe, it is also neceffary for covering the infide of Copper, Brafs, and Iron veffels, to preserve them wholfome for culinary ufes; whence there is a large confumption for tinning Brafs ware and the like: it is ufeful alfo in foldering; but I believe the compound Metal of Pewter, of which it is the principal ingredient, is preferable for that purpose. Befides its domeftick ufes, it is a neceffary article, when diffolved in Aqua Fortis, for the new scarlet or Bow die. And if I am rightly informed, our most beautiful and lafting coloured fine cloths owe their fuperlative excellency to the retentiveness given by our fineft grain Tin; infomuch, that the English fuperfine broad cloths, dyed in grain by the help of this ingredient, are become famous in all markets of the known world.

It is more than probable, that the purple die of the Tyrians gained the very great reputation it had among the ancients, in great part, if not wholly, from their use of our Tin in the compofition of their die ftuff, as the Tin trade was folely in their own

T

management

management and direction. I think the known facts of its being their monopoly, the exceeding usefulness of it as one of the non-colouring retentive ingredients, and the fame in all parts of the world of the unfading colour of that purple which is fuppofed to be given by the juice or faliva of a certain fhell fish called Purpura, do very much preponderate towards my conjecture.

We may be certain, that almoft the fole traffick to this island four and twenty centuries ago, was for this Metal; and we have before obferved, that in thofe very early ages, our Tin was fold to the Phenicians, who (like the prefent Hollanders, the grand carriers of Europe) tranfported the commodity in their bottoms to all foreign parts. "Tyrus, O thou that art fituate at the entry of the fea, which art a merchant of the people for many ifles.'

(Ezekiel).

Jefus the fon of Sirach, the author of Ecclefiafticus, lived 247 years before Chrift. In fpeaking of Solomon's glory,

chap. xlvii. verf. 18, he fays, " By the name of the Lord God. "which is called the Lord God of Ifrael, thou didst gather “Gold as Tin, and didst multiply Silver as Lead.” Which fhews that Tin in those days, viz. 247 years before Chrift, was exceedingly plenty in the Holy Land. And it is remarkable, that Tin and Lead in this place, are both mentioned, and distinguished; fo that the latter cannot be taken or meant for the former, as they have been mistaken and confounded together for one Metal by others, though characteristically different. By the ships Solomon fent out, he had a return in one voyage only, of no less than 420 talents of Gold; therefore it is expreffed, 1 Kings x. 27. Money was in Jerufalem as Stones for plenty." How vaftly plentifull muft Tin have been then in Jerufalem, to be spoken of in the above figurative way ?

We cannot, however, fay pofitively, that no other country produced this Metal in those days; but if it was then known in other nations, it was very little fought after, and was estimated as a staple by no country except Cornwall. Pliny fays, it was found in Gallicia and Lufitania, but not at a depth or in quantity to merit much attention. A Tinner, in the time of Richard earl of Cornwall and king of the Romans, upon fome disgust at home, went over to Saxony, and taught the natives to seek for Tin, and render it merchantable: they have to

this

this day fome workings for Tin, though of no further account, than for their own confumption. Alonzo Barba, fays, that they had rich veins of Tin at Oruro and Potofi; but their vicinity to fuch immense Mines of Silver, is the reason of their being never worked to any purpose. A great deal of Tin has been imported into Europe these latter years from the Moluccas, some bars of which the writer has feen equal to the best Cornish Grain Tin.

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