hand barrows full of flime, where it mixes with a little rill of water that floats it down into the femi-circular pit P called the Head or Pednan, wherein a boy treloobs or ftirs the flimy water round about with a small shovel, that the water may wash away both the filth and Tin over a cross board ten inches deep at the lower part of the pednan: the board is somewhat lower in the middle than at each end, for admitting the watery mixture with more ease into the body of the trunk O, R, R: that which refts in the fore part of the trunk at Oo, is carried off to be framed, and the settlement at R, R, is moved forwards to P, to be trunked over again before it is fit for the frame: the rough grains lie at the bottom of the ftrêk, whence it is removed for stamping, and the most light and fmall flime paffes the bottom or lower end of the trunk into a pit, where it fettles and acquires the name of Loobs.

The frame or rack T W, confifts of two inclined planes of timber; the body W, the head T. The frame is an oblong fquare eight feet by five, with fides four inches high, all joined closely, that nothing may escape but at the extremity or lower end. At the middle of the two ends are fixed two round projecting irons called Melliers, by which the frame hangs and turns as it were on an axis, upon two upright pieces of timber one at each end, whereby the frame may be fwung up and down, perpendicular to the horizon. The head T, is two boards wide, and in length parallel to the breadth of the frame. To the bottom of this is joined a water head, or board, seven inches high; to which is hung, by hinges, a flight piece of board fix inches wide, and the length of the head, called the Lap, or Lippet, whose use is to convey the water and Tin equally down upon the frame. the frame. Underneath the fore part of the frame, is fixed a little tray or chest three feet long, called the Kôfer, and another at its lower end called the Hind-Kôfer.

The water falling in a gentle manner from S upon the head T, wafhes the Ore, which there offers itself (as at the buddle) in little ridges, downwards over the lippet, upon the body of the frame W. On this frame the water is fpread fo thin, and runs fo flowly, (the plane being very little inclined) that by moving the flimy Tin to and fro with a light hand, and expofing it cautiously to the water by a small femi-circular toothless rake, all the fordes are washed away, and the Tin though ever fo fmall, remains on the frame near the head. When the Tin is found fufficiently clean, the body of the frame being hung on

melliers,

melliers, as I have said before (by flipping the stake underneath, which fupports it) is turned eafily from horizontal to perpendicular; and the Tin which remains on the frame runs off, by the affiftance of a little fprinkling, in two degrees of purity, into the fore and hind kôfers. The frame is then righted into its horizontal pofitions, and the procefs repeated till the kôfers are full. The smaller flime, which runs off the lower end of the frame, is yet preferved in a pit by the name of Catchers, and makes a part of the loobs or leavings of leavings, to be worked over again at a future time. The contents of the fore kôfer is then fifted through a fine hair fieve or copper bottom, into a keeve with water in it, to feparate the gravel, chips, or any other accidental mixture from it. Then it is buddled and faved in different portions, like crop Tin; as well undergoing the feveral operations of toffing, packing, fkimping, dillhuing, &c. After all, if the Tin is very small, it is carried to the frame again, and reframed or cazed, as they term it; which is performed, by stoping the lower end of the frame with mud and turf, that the water may be almoft ftill, and the Tin more easily fettle upon the frame, and defcend the more furely into the kôfer: the fore kôfer is then emptied the fecond time, the Tin carried to the keeve again, there toffed, packed, fkimmed, &c. and thus the flimes are finished, and brought to as great a degree of purity, as the fize of the Tin will permit, which being exceeding small, will neceffarily have somewhat more of waste, than what is larger and heavier.

The great pile of tails behind the buddles, are commonly wafhed down into the trunk below, by a pretty strong current of water, which may be rendered more or lefs forcible by an alteration of its fall, to divide the rough from the small, by treloobing them in the femi-circular kôfer of the trunk with a fhovel. The fmall that flashes over into the trunk, is defigned for framing, and fo divided into two parts, the fore, and the hind kôfer. The latter must be toffed and framed again; but if the fore kôfer is pretty good, it may be toffed and packed, the skimpings of which must be cazed in the buddle, that is, one perfon buddles it as ufual, but with a very small flow stream of water, while another with a few quils fixed on the end of a pole, lightly sweeps the buddle across from fide to fide, beginning at the bottom, and fo proceeding forward every ftroke, till he comes to the breast of the buddle, when he returns in like manner progreffively to the end or tail. By this method it is made fit for cleanfing in the keeve, &c. and the hind part,

that

that is not fit for toffing, &c. must be framed again, and proceeded with in the former manner.

Mean time, all tails that are taken from the bottom of the trunk head or pednan, together with the roughs (or rows) that come from the flime, or from the toffings of the hind and fore kôfers, that are not of a proper size, must be stamped over again, and dressed in the manner before mentioned for bringing about the crop Tin or bal work. But in the ftamping them, care must be taken to fuit them with a proper grate and small weight of tackle, or worn old ftamp-heads; otherwise they may be stamped under fize, and choak the grate, which they call being dumbed; to prevent which, they mix with them a small quantity of Goffan or poor Tin-ftuff, to cut and jagg them up, elfe the ftamp-heads would mudify them too much to pass the grate holes as freely as they ought: nay I have known common Quartz used for this purpose, entirely deftitute of Tin. If there be a corrupt brood in the leavings Tin, fo as to damage its value two parts in twenty, it must be burned in the manner before directed, but with a lefs violent fire, and then dressed again from its calcined impurities: the calcination of leavings Tin should, however, be always avoided if poffible, because it is fo fine, like floran Tin, that it will, by its fized levity, be elevated and carried off, together with the arsenick and fulphur.

The modes of dreffing Tin and its leavings, are too various to lay before the reader, without danger of prolixity: all of them depend upon the difference of the kinds of Tin in the ftone, and must be dealt with, agreeable to the judgment of several manufacturers. So much depends upon the skill of a dreffer, that one may fave one-twelfth part of a batch of Tin, which another for want of equal knowledge may caft away in wafte, or perhaps take up fo much waste with it, as to depreciate the value of the whole by two parts in twenty. Neverthelefs, all dreffers fave the hinder ftuff from the frame end, as it washes off in a pit by the name of Catchers, which is expreffive enough; and likewise the mud at the trunk ends, by the other name of Loobs, both of which are denominated the Loobs, after leavings, or leavings of leavings. These are wrought over in the fame manner as the former, moftly upon tribute, by an aged workman and a few little boys in the fummer months, when they can stand out in good weather, and do a long day's eafy labour. The tribute paid by the undertaker is one-third Nnn

of

of the produce in white Tin; the other two-thirds he has for himself to pay his coft and charges.

Proceeding upon this fingle principle, that the force of water, properly applied and introduced among the particles of Tin Ore and the fordes mixed with it, will disperse the latter and leave the former at rest for them to collect and treafure up, they vary their operations inconceivably, conducting them with great ingenuity, leffening, encreafing, diffufing, or contracting their water, the great inftrument of purity, as the fize, weight, and combinations of the Metal and its feeders require; and that with great cafe, cheapnefs, and regularity, throughout the feveral proceffes.

Hence, this business of dreffing is a particular trade, entirely different from that of the labouring Miner; and is best learned under a master workman, who makes it his fole occupation to follow the ftamping mill and the works belonging thereto. This mafter workman hires boys from feven years old to eighteen, gives the former about three fhillings a month, and raises their wages as they advance in years and workmanship, till they have man's wages, viz. at the least twenty-four fhillings, at the highest thirty fhillings & month. This is of double benefit to the poor parents; and the boys being taken in fo young, become healthy and hardy by using themselves to cold, and to work with naked wet feet all day; and they learn early to contribute to their own maintenance. Each stamping mill which has conftant work and water, will employ one man and five boys; and one hundred facks are carried, ftamped, and dreffed, in the space of a few days, at the average rate of about fourpence & fack, or one guinea and a half hundred.

We fhall here observe, that even burnt leavings of Tin are often confiderably valuable, efpecially if they are cupreous; and even the pooreft of these leavings bring ten or twenty fhillings ☞ ton; which is better than to throw them away, as was the case no further back than forty years. All burnt leavings taken from Tin-stuff, till the year 1735, were efteemed good for nothing. But in that year there were several small parcels lying on fundry stamps plots in this parish, which induced Mr. Morgan Bevan, an old experienced affayer, to try whether he could reduce them into Metal. For the first time he affayed a fample of three tons; and, to his own great surprise, as well as that of others, he found that he could give seven pounds four fhillings

and

and fixpence ton for them, which he actually did, and prefently after bought several parcels more of Meffrs. Carter, Reynolds, Penrofe, Cornifh, &c. the principal Tin dreffers of those days. From that time all burnt leavings were taken much care of, provided they were fufficiently impregnated with Copper; for fome of them are merely Mundick, with little or no Copper in them. When the Brass-wire Company carried on the great Tin Mine of Chacewater, before this discovery they caft fome hundred tons of burnt leavings, to their great prejudice; but fince that time there have been large quantities fold from the fame Mine.

away

The very water in which burnt Tin is wafhed, may be converted to a useful and profitable account, either by evaporation to a pellicle for crystallization of Copper, commonly called Blue or Roman Vitriol; or for the precipitation of Copper by the medium of Iron, laid in veffels filled with this vitriolick water. The precipitation of Copper by Iron, is too generally understood to make an explanation neceffary here; but we have obferved among our Copper precipitate, where it has been effected by a very strong folution with the cleaneft Iron, several pieces of malleable Copper, fome of them retaining the form of the Iron, like incruftations fallen off from it. Hence it seems as if there was a degree of attraction between the Iron and the particles of Copper, floating in the water; as well as the more obvious attraction between the acid and the Iron. Muft not the particles of Copper thus attracted, cohere by their own magnetism, or the attraction of cohesion ?

It may not be improper to add how far this quality has already tended or may tend to the advantage of the publick. Perhaps the history of its rife and progress in this country, and in Ireland, may ferve to illuftrate that matter. About fixty years ago, this phenomenon was first observed by Mr. Cofter in Chacewater Mine near this town; for after he had drawn ouf the water, which had been in the Mine for several years, he found the poll of a pick-axe wholly encrufted with a case of malleable Copper between two and three pounds weight. This it was justly suppofed was obferved by the workmen, fome of whom afterwards fettled at Cranbaun Mine in the county of Wicklow in Ireland. The water of Cranbaun having this vitriolick acid in a very high degree, Capt. Thomas Butler, who was one of Redruth, and manager of that Mine, perfuaded the proprietors to adopt the scheme of precipitating Copper, of