BOOK IV.

СНАР. І.

The Method of Sampling and Vanning of Tin-ftuff, with the Stamping, Burning or Calcining, and Dreffing the fame; with the Manner of Dreffing the Leavings, Loobs, &c.

T

IN-STUFF that lies by the fide of the Shaft, when it becomes a great heap, or if it otherwise fuits the humour of the concerned, is firft fpalled or broken to the fize of a man's fift or lefs, by which the most indifferent parts are separated and forted from the beft; fo that perhaps not more than one half of a large heap may be reserved for dividing and ftamping. After the Tin-ftuff is thus culled, and properly fized, it is divided out in fmaller heaps by measure of a handbarrow, that usually contains a fack and a half, or eighteen. gallons. These fhares, which they term Doles, are parcelled out into fo many different heaps on any the most adjacent parts of the field, fometimes to the great prejudice of the husbandman, who is not confidered for his damage by the lord of the foil, or the owners of the Mine. The method and number of Doles, into which Tin-ftuff is frequently divided, may be seen in book iii. chap. iv. The parcels being laid forth, lots are caft; and then every parcel has a diftinct mark laid on it, with one, two, or three ftones; and fometimes a bit of stick with the initials of the proprietor's name, or a turf laid on the middle of the Dole. When these marks are fixed, the Doles may continue there unmolested for any length of time: the property is fettled; and no one, but the right owner, may add or take from it.

The Doles which are defigned for fale, are very accurately measured; for as the barrows are carried off for their respective divifions, one perfon, who is the reckoner, keeps an account by making a notch in a stick for every barrow; and if there be an odd one left, it is equally divided by the gallon, the shovel, and, when it is rich, even by the handful. The Doles being divided, they proceed to caft lots for that which fhall be

fampled.

fampled. This Dole being turned over, equally levelled and mixed, is then divided by a man with his fhovel, into two equal parts, taking a little of the Tin-stuff from one end to the other of each of thofe parts to the amount of fome gallons if the Dole is pretty large. This quantum is bruised down by large fledges to the fize of an hazle nut, then equally levelled and divided into four parts, two oppofite quarters of which are felected and bruised over again to a fmaller fize. These reductions and smaller divifions are repeated again and again ad libitum; till the quantity defigned for fampling, is well mixed, and made as fine as common fand; when each fampler fills his little canvas bag with it, and proceeds to a trial of its value by water, in the following manner.

The more

To make a rough guefs or coarfe effay, the fampler takes a handful of it, and washes it on a fhovel, till the impure earthy parts are carried off by the water from its fides. ftony, folid, heavy particles being left behind, they are bruised by an affistant, with a fledge on the fhovel, till the whole affumes the appearance of mud. This is washed again, till it lofes its muddy afpect; when by a peculiar motion of the shovel not to be described, the metallick particles are collected together on the fore part or point of it. By repeating these bruifings, wafhings, and motions, it becomes clean black Tin, fit for the fmelting furnace. This is called a Van (from the French word Avant, foremost, as I apprehend) it being thrown forth upon the point of the fhovel, by the dexterity of the fample-trier. After the Tin is thus made clean to his mind, he dries it; and if it be as much black Tin as will entirely cover a good fhilling, or rather if it is the weight of a fhilling, he terms it a Shilling Van, which is not rich; but if the Van will cover or equal the weight of a crown piece, it is good Tin-ftuff, and is termed a Crown Van. Now they fay, the Shilling Van will produce one hundred grofs or avordupois weight of block or white Tin; and the Crown Van will yield five hundred weight of block Tin, for every hundred facks in measure, of the respective Doles that the fample or Van is taken from, and fo proportionally on, to the richeft Tin-ftuff called Scove, which is reckoned ten thoufand of white Tin-metal every hundred facks; or in other words, it will produce one hundred hundred weight of Tinmetal, for each hundred facks of Tin-ftuff; yet there is none near fo rich as this in any quantity, except a particular stone or lump.

But

But a measure of a wine half pint is much more exact and true than a handful, to form a judgment from; though the handful be accounted a half pint. The manœuvre is alfo more nice and true, by using a large shovel, and taking off the sized Tin from time to time on another fhovel, and fo proceeding till all the Tin is reduced clean and to a proper fize. When this is done, dry the Van in a shovel upon the fire; then take it off and weigh it in a money fcales by pennyweights and grains: for every pennyweight and half the Van weighs, the produce will be one hundred weight of black Tin for every hundred facks of Tin-ftuff; and fo on in due equation: three pennyweights is equal to two hundred weight; fix pennyweights to four hundred weight; twelve pennyweights to eight hundred weight; fifteen pennyweights to ten hundred weight; or, as they term it, a thoufand of black Tin a hundred, i. e. for every hundred facks of Tin-ftuff: and if it be Tin worth ten for twenty, or one for two, then the Tin-ftuff is valued at five hundred weight of block or white Tin, for every hundred facks. hundred facks. If the Tin be worth twelve for twenty, the ftuff is valued at fix hundred weight of white Tin a hundred ; or if it be worth only eight for twenty, it is only valued at four hundred weight of white Tin a hundred; and fo if the metallick quantity of the Tin be more or lefs, it must be accounted for after that manner.

This black Tin is rather of a liver colour, though called black in contradiftinction from white Tin, or the Metal produced from this black Tin Ore. It is very ponderous; for, in a general way, it may be computed to hold one half clean Metal, and fome of it will produce thirteen, nay even fourteen parts in twenty; whence the term of fo much white Tin for twenty of black Tin, that is, eight for twenty; ten for twenty, which is the fame as one for two; twelve for twenty, and fo on, be it more or lefs given for Metal; in the knowledge of which the fample-triers or Tin-dreffers are very expert, without the ufe of crucible and furnace. Thus if the Van of one hundred facks of Tin-ftuff weighs fix pennyweights, being four hundred weight of black Tin at twelve for twenty, the white Tin or Metal must be two hundred weight, one quarter, fixteen pounds.

In the preceding manner, they form a near conjecture of the quantity of white Tin that their work or Doles of Tin-stuff will produce at the fmelting-house, when it is dreffed, and brought into black Tin. But if the black Tin is infected with any bad brood or mixture, as Mock-lead, Copper, or Mundick, after

the Van is bruised fine and washed, they lay the fhovel over the fire, and burn the black Tin, continually stirring it till it fmokes no more. Laftly, they wash it again on the fhovel, and fo the brood is carried off by the water, it becoming light by being burnt; for when black Tin is calcined or burned, it still retains its fpecifick gravity; but Copper, Lead, and other crude Minerals, become much lighter by torrefaction, and are easily separated from the Tin by water.

It should be observed, that each fack ought to hold twelve gallons of Tin-ftuff, though they often hold but nine or ten; which want of measure, when known, fhould be taken into confideration by the Tin buyer.

Now, whoever intends to buy a quantity of Tin-ftuff, either for profit in trade, or merely for the fake of employing his ftamping mills, horfes, and labourers; when his adventure Tin-stuff falls fhort, which is very commonly the case, he must not give the value of its full produce, without deducting what is called the returning charges, that is, the carrying, ftamping, and dreffing thereof. On the other hand, the reader must be apprifed, that the value of Tin-ftuff, is fhort of its intrinfick worth by the Van only; for in the dreffing and management of Tin by ftamping, &c. there are two forts of black Tin to be obtained, viz. the crop and rough, or the crop and leavings of Tin. The firft is the prime Tin, immediately feparable from the bafer parts by its fuperior weight and richness; the latter is that which is carried off, and mixed with the lighter earthy parts, by its being under fize, and therefore more fufceptible of the force and impreffion of a determinate ftream of water. Such Tin being compofed of the most flimy moleculæ, as well as of the larger rough grains, which get through the greater fized holes of the ftamping-mill grate, have very little Tin in them, and must therefore undergo another treatment to get out and cleanse the Tin. This being called the leavings, muft be accounted for and valued in addition to the crop Tin, in proportion to the denfe or lax confiftence of the Tin-ftuff and the fpecifick granules or minutiæ of the Tin Ore in the stone. All this depends upon the experienced judgment of the Tindreffer; and it is fo difficult and various a fubject, that a man fimply a theorist in the matter, cannot lay down a certain rule on which another can abfolutely depend. The customary valuation is, by setting a price upon the leavings of this or that Tin-ftuff, according to fo much the ten hundred weight or

thoufand

thousand it makes in crop Tin, from fifty fhillings to five pounds thoufand for the leavings. Hence it follows, that the leavings of fome Tin-ftuff will more than pay the returning charges; but whenever the leavings are rich enough to pay those incumbrances, they pronounce fuch Tin-ftuff to be "Tin in the "Bal;" that is, to be worth four, five, or fix hundred of white Tin hundred facks by the Van, free of all costs and charges, which the leavings will exonerate.

All things being well confidered, we may conclude, by trying the sample, how to fize a parcel of Tin-ftuff by fuiting it with a grate or holed plate, adapted to the natural grain of the Tin, which is one of the principal articles in dreffing; but of this in its place. Mean while let us obferve that the dreffings of Tin in its present improved state, has been very lately invented; for by Mr. Carew's account, no longer back than one hundred and eighty years, in queen Elizabeth's reign, the manner of dreffing was exceeding flovenly; and I am very fure, notwithstanding our prefent advance, we are yet at fome diftance from perfection in that art. He fays, "As much almoft dooth it "exceede credite, that the Tynne, for and in fo fmall quantitie

digged up with fo great toyle, and paffing afterwards thorow "the managing of fo many hands, e're it come to fale, should "be any way able to acquite the coft; for being once brought "above-ground in the ftone, it is first broken in pieces with "hammers; and then carried, either in waynes, or on horses "backs, to a stamping-mill, where three, and in some places "fixe great logges of timber, bounde at the ends with Iron, " and lifted up and downe by a wheele, driven with the "water, doe break it fmaller.

upon

"The ftreame, after it hath forfaken the mill, is made to "fall by certainne degrees, one fomewhat distant from another; each of which, at every difcent, lyeth a green turfe, "three or four foot fquare, and one foot thicke. On this the "Tynner layeth a certayne portion of the fandie Tynne, and "with his shovel softly toffeth the fame to and fro, that, thro "this ftirring, the water which runneth over it, may wash away the light earth from the Tynne, which of a heavier "fubftance lyeth faft on the turfe. Having fo cleansed one "portion, he fetteth the fame afide, and beginneth with "another, untill his labour take end with his taske. After it "is thus washed they put the remnant into a wooden dish, "broad, flat, and round, being about two feet over, and

"having