earth, and on its fuperficies; which by the impetuofity of the waters, and fituation of particular places, were molefted in fubfiding. For we are not to fuppofe our globe to resemble a trough, or the like excavated figure, wherein the variously mixed earths are to be regularly difpofed, as in the operation of buddling or washing of Ores; but to be of a spherical arched figure, where the waters, as on a hanging bottom, powerfully rend, and pull it asunder and this force of the waters we may fuppofe to be greatest at the beginning and end of the deluge.

:

So likewife, in fome places, the loofe earth and stone, which cover the firm rocks, lie in ftrata; for immediately on the rock, there may be, for inftance, a layer of fand or clay, and over that a bed of large ftones, and fo alternately ftratum fuper ftratum, for fome depth. Now these variations might very well happen on the decrease of the deluge: for when the flood was high and more at reft, the flimy light earth was depofited downwards; but when the waters came lower, and bent their courfe to the beach, then it came to pafs that there was a strong current from off the land to the fea, which rolled down the loofe ftones upon the mud or fediment that fell and fettled beforehand; fo this current might have been interrupted again by the fituation of the place and interpofition of high ground, till the water had let fall another fediment, and afterwards found or perhaps broke another paffage for itself through the land. This might have happened feveral times in the deluge, till at laft the remaining water partly evaporated and partly funk into the ground, leaving the deepest earth or sediment where it continued longeft; as it happens frequently in floods or overflowings of water, where we may obferve the fituation of high and low grounds do not a little contribute to the fame kind of effects that are here spoken of.

Another way of discovering Lodes, is by working drifts across the country as we call it, that is from north and fouth, and vice verfa. I tried the experiment in an adventure under my management, where I drove all open at grafs about two feet in the shelf, very much like a level to convey water upon a mill wheel; by fo doing I was fure of cutting all Lodes in my way, and did accordingly discover five courfes, one of which has produced above one hundred and eighty tons of Copper Ore, but the others were never wrought upon. This method of discovering Lodes, is equally cheap and certain; for a hundred

fathoms

fathoms in a fhallow furface may be driven at fifty fhillings

expence.

In feasible (tender ftanding) ground, a very effectual, proving, and confequential way is, by driving an adit from the lowest ground, either north or fouth; whereby there is a certainty to cut all Lodes at twenty, thirty, or forty fathoms deep, if the level admits thereof. Such depths are proving the Lodes difcovered by them, and the adit will ferve to drain all parts of the ftrata above it; and likewise be a discharge for all water drawn from the Mine into it; fo that it is effectual for discovery, proving for trial, and confequential to the future working of a Mine. But in Granite, Elvan, and Ireftone ftrata, this cannot be complied with, neither is it adviseable but under certain circumftances, where the ground is to be wrought for eighteen fhillings fathom, unless a Crofs-Goffan lies ready at hand, when the method in ufe is to drive partly on one fide of the Goffan, breaking down the adjunct wall of it, whereby they drive the adit cheaply, expeditioufly, and effectually for discovery. In driving adits or levels across, north or fouth, to unwater Mines already found, there are many fresh Veins discovered, which frequently prove better than those they were driving to. nefs the Pool adit in Illugan, where the late John Pendarvis Baffet, Efq; cleared above one hundred and thirty thousand pounds.

Wit

СНАР. II.

Of Streaming, and Smelting of Stream Tin in the BlowingHoufe, &c.

E cannot help repeating in this place, that the deluge

WE is an event which has produced the most remarkable

alterations in the earth, and to which many effects obfervable at this day are to be afcribed. The hiftory of the deluge gives great light towards the knowledge of nature, and the prefent ftate of the earth feems to verify that event: by the violence of the deluge the Mineral kingdom was thrown into confufion, parts before conjoined were feparated, Ores and Veins were dislodged, and new beds and pofitions given them. The feveral ftrata in which Minerals are at prefent found, afford convincing inftances, as well of the truth of this event, as of the confufion wrought by it, especially

especially in parts where Clay, Sand, Rubble, Stone, and the like, lie in beds and layers on each other. But I fuppofe there are no particular inftances under the fun, that can afford us so clear an idea of the flood and its effects, as the Stream works in St. Auftle, Roach, St. Dennis, St. Stephen's, Luxillian, and Lanlivery.

It happens that what I have already faid in my account of fhode and fhoding, together with my fection on the article Tin in chapter the 3d, book the 1ft, leaves little more for me to fay on the fubject of Stream Tin. I muft, therefore, wave the defcription of it here, and refer the reader back to those places. Of course nothing else remains than to defcribe the manner of Streaming, upon which I fhall be concife because it is a part of my fubject that is very fimple and lefs important than deep Mining to the community in general; but as it occurs, in the course of my writing, more naturally in conjunction with or immediately after the method of fhoding, I beg leave to introduce it in this place.

When a Streaming Tinner obferves a place favourable in fituation, he takes a leafe, commonly called a Set, of the land owner or lord of the fee, for fuch a spot of ground, and agrees to pay him a certain part clear of all expence in Black Tin; that is, Tin made clean from all wafte, and ready for fmelting. The confideration is generally one fixth, feventh, eighth, or ninth, as can be fettled between them; or, inftead thereof, he contracts to employ fo many men and boys annually in his Stream work, and to pay the land owner, for liberty, from twenty to thirty fhillings a year for each man, and fo in proportion for every boy; that is, for twelve fhillings monthly wages, he articles to pay the lord half as much as for a man.

He then finks a hatch (fhaft) three, five, or feven fathoms deep, to the rocky fhelf or clay; on both of which in the fame valley, the Tin is frequently ftratified, without any difference in its being more abundant in one than the other. It is found in different places, in different depths; and sometimes stratified between what is called a firft, fecond, or third fhelf, which is reconcileable upon the principles laid down in my chapter upon fhoding, &c. The ftratum of Stream Tin may be from one to ten feet thickness or more; in breadth, from one fathom to almost the width of the valley; and in fize, from a wallnut to the finest sand, the latter making the principal part of the

Stream,

Stream, which is intermixed with ftones, gravel, and clay, as it was torn from the adjacent hills.

When he finks down to the Tin ftratum, he takes a fhovel full of it, and washes off all the wafte; and from the Tin which is left behind upon the fhovel, he judges whether that ground is worth the working or not. If it is proving work, he then goes down to the lowest or deepest part of the valley, and digs an open trench, like the tail or low flovan of an adit, which he calls a Level, taking the utmost care to lofe no levels in bringing it home to the Stream. This level ferves to drain and carry off all water and wafte from the workings, in proportion as he hath a weak or powerful current of water to run through it. places are very poor and not worth the expence for working; others again are very rich and thence called Beuheyle or Living Stream, as is most commonly the cafe if it is of a Grouan nature, which being more lax and fandy, is more easily separated from its native place or Lode, and therefore more abundant and rich in quality according to the known excellence of Grouan Tin.

Some

In the latter cafe, the Streamer carries off what he calls the Overburden, viz. the loose earth, rubble, or ftone, which covers the Stream, so far and fo large, as he can manage with conveniency to his employment. If in the progress of his working he is hindered, he teems (or lades) it out, with a scoop, or discharges it by a hand pump: but if those simple methods are infufficient, he erects a rag and chain pump fo called; or if a rivulet of water is to be rented cheaply at grafs, he erects a water wheel with ballance bobs, and thereby keeps his workings clear from fuperfluous water, by discharging it into his level: mean while his men are digging up the Stream Tin, and washing it at the fame time, by cafting every shovel full of it, as it rifes, into a Tye, which is an inclined plane of boards for the water to run off, about four feet wide, four high, and nine feet long, in which, with fhovels, they turn it over and over again under a cascade of water that washes through it, and separates the wafte from the Tin, till it becomes one half Tin.

Though there is little dexterity in this manœuvre, yet care is requifite to throw off the Stent or rubble from the tye to itself, whilst another picks out the Stones of Tin from the Garde or smaller pryany part of it. During this operation, the best of

M m

the

the Tin, by its fuperior gravity, collects in the head of the tye directly under the cafcade; and by degrees becomes more full of waste, as it defcends from that place to the end or tail of the tye, where it is not worth the faving. If there is a copious ftream of water near at hand, they caft this refufe into it, by which it is carried fo far as to make its exit into the fea, for which practice they certainly deferve our feverest cenfure; at leaft, if the choaking of harbours and rivers, and the destruction of thousands of acres of improvable meadow land, are not more than an equivalent for the cafual and temporary profits arifing from Stream Tin.

I need not mention, that in the ufual method of Streaming for Tin, the foil is either thrown into the bed of the rivers, or buried under the gravel and ftones that form the interior strata ; by which fuch land is rendered irreclaimable. That the Bounder, or working Tinner, fhould thus wantonly destroy what he had no interest in preferving, feems by no means extraordinary; but can we say the fame for the lord of the foil?

Surely, it did not require any great degree of penetration, to have comprehended Streaming and Draining under one idea, and thus have made the improvement of the surface go hand in hand with the extraction of the Tin. The additional trouble of removing back the foil in heaps, and levelling the Stream ground to receive it, is fo little that I know, by feveral instances, the Tinner will have but little reluctance in acceeding to; which the reader will readily apprehend when I affure him, the overburden upon the Stream is digged and rolled off at some distance, for only eightpence a cubick fathom; but at all events it is the intereft of the proprietor to have it done, either by the Streamer or fome other perfon. This method has been pursued in fome parts of the county of Cornwall, and has been attended with the fuccefs fo laudable an undertaking merits; as thereby those springs which lie too deep for the ordinary modes of draining, have been moft effectually cured. I hope I fhall not be accused of exaggeration when I affert, that the rental of this county, by following this obvious method of procedure, might have been increased in a proportion almoft equal to the prefent value of the Stream Tin; and this too without leffening its produce, or injuring in the smallest degree the ducal revenue.

That this practice was not adopted by our ancestors, was owing to the small comparative value of land in those days,

confidering