yet makes other metals fo, when mixed with them. In point of gravity, it is as feven to one, in respect to water, and as feven to nineteen in regard to gold. Tin mines are generally found on the fides of hills, though veins fometimes pafs through vallies or brooks between two hills, and are followed to the oppofite hill. They work with infinite difficulty through hard rocks, to the depth of from three to feventy fathoms; and the labour is not leis troublefome than dangerous, where the earth is loose and apt to crumble. Great quantities of timber are confumed in these fubterraneous works, which are freed from water by the help of fire engines, and other contrivances. The veins are of uncertain thicknefs, from three inches to three feet. Tin grains or corns of tin, yield five parts in eight of metal; whereas tin ftones yield only from one in thirty, to one in fixty, and to one in a hundred and twenty, for even thefe are wrought to fome small profit. The ore when collected is broke, wafhed, ftamped by mills, and otherwife treated to fit it for the melting houfe, which is called drefling; except the tin grains which need no fuch préparation; after melting, it is called black tin; but before it can be exposed to fale it is carried to one of the five coinage towns, where after examination of a piece that is broke from a corner of the block, the arms of the Duchy of Cornwall are impreffed with a hammer, and then it is called white tin. The duty on coinage, which is four fhillings on the hundred weight, belongs to the Prince of Wales as Duke of Cornwall, and produces a great revenue. The ufes of tin are many; it is fometimes given in medicine; preparations from it are employed as cofmetics; it is ufed in varnishing earthen ware; in conjunction with mercury it makes the foilage fpread on the back of looking glaffes; amalgamated with quickfilver, fulphur, and fal ammonize, it produces the mofaic gold; the calx polifhes glafs, fteel, &c. the compound calx is what we call putty; it is also used in folder: Another manner in which it is ufed in this and in other countries, is what is called tinning, by which copper veffels are rendered neater in appearance, and fafer in ufe. When applied on thin plates of iron, it becomes fit for many ufes, and furnishes a variety of handsome and wholefome utenfils; it enters into the composition of bell metal, of printers' types, and to it are due the elegance, hardness, and beauty of our pewter. The deep ruby colour extracted from gold used by painters in enamel, is made by precipitating the folution of that metal in Aqua Regia, with ealx of tin, and in this refpect it is highly ufeful in ftriking all farlet dyes.

Notwithstanding the copious production of tin in England; the tin plates were long imported from Germany. Andrew

*This is not the painters or glaziers potty, but a powder of calched tin, used in giving the last pohith to fine works in fteel, dve.

Yarranton,

Yarrantón, in a work entitled England's Improvement by Sea and Land, (2 Vol. 4to. 1681) afferts that tin plates (i. e. iron plates tinned over) were made in England through his means, he having been employed by fome gentleman to go to Bohemia, where he learned the manner of making them. When he returned home, he fet proper perfons to work, who made better than any he had feen abroad, the metal being better, and the plates more pliable; but a patent being obtained by fome great man at court, who had difcovered the fcheme, for the fole making of them, that manufacture was dropped by his employers, who had with fo much charge made the difcovery. The art thus faid to have been imported remained for many years unpractifed in England, infomuch, that among the bubbles of the year 1720, this was one; yet, fince that time, the manufacture of tinned plates is brought to greater perfection in England than in any other part of the world. In 1740 it was obferved that few tin plates were imported from foreign parts: our own being now made of a finer glofs or kin than that manufactured beyond fea; that being hammered, and ours being drawn under a rolling mill. This improvement is a confiderable benefit to the nation in the general annual balance of trade; a great quantity of this article being confumed in Britain, Ireland and the plantations. That which is called japanned tin, and the manufacture of Pont-y-Pool are brought to unrivalled perfection, not only exhibiting the richest aud gayeft tints of colouring, but pictures exquifite in defign, mafterly in execution, and durable as the metal on which they are difplayed.

COPPER. Copper is plentifully found in all the British territories; yet, though long known before, our mines were not wrought to any great purpofe till the eighteenth century. Lately, indeed, the produce has furpaffed all previous calculation, in confequence of the difcovery of the treasure contained in the famous Paris mountain in Anglefea. This metal is fometimes found pure, or very nearly fo, and that in fo large picces as to make it neceffary to break them in the mine before they can be conveniently raifed; but in general, like other metals, involved in ftony crufts of all colours, and even many of thefe are beautifully blended together, whence the ore receives the name of the peacock's tail. This ftony ore is fo intimately mixed with, and adheres fo clofely to, the metal, that it is extremely difficult to feparate them, which is one principal cause of the dearnefs of copper. This metal is of a bright orange red, close, hard, malleable, ductile into wire, fonorous, and elaftic; and is not only wrought on by all folvents, but even by water, which makes it very apt to ruft. In point of gravity, it is as nine to one in refpect to water, and in regard to gold as nine to nineteen. The mines are wrought to a great depth, fometimes to

more

more than a hundred fathoms, often through a very hard rock, and confequently with much labour and a vaft expenfe. The feparating the metal from the ore is a very arduous and intricate operation; for firft it is broken to pieces in the mine, then raifed, ranged according to its fizes, washed, picked, ftamped, and forted. When brought to the melting house, it is firft roafted, next ftamped again, and then melted, when it is styled red copper, and having ftill heterogeneous fubftances mixed with it, melted over again perhaps more than once, and then it is ftyled black copper; if it is fufpected to hold filver, as it frequently does, it is returned to the furnace, where a proportion of lead is added, and then it is expofed only to fuch a degree of heat as is fufficient to melt the lead, which attracts and carries away the filver, leaving the block of copper honeycombed. This is afterwards melted, and becomes at laft what is called rofe copper, that is, perfectly fine and pure, The ufes of this metal, like thofe of iron, are too numerous to be inferted here; it may be fufficient to observe, that its malleability, flexibility, ductility, and elasticity, render it fit almost for every thing to which metal can be applied. Befides it is to be remembered, that from copper brafs is made, and thence all the Humberless articles that are manufactured for public and private ufe, from our heavy artillery down to the furniture of the kitchen, and, which occafions no fmall confumption, drawn into wire for pins.

The mine in Anglefea demands particular notice. The name of the place, in which it fubfifts, the Paris mountain, is fuppofed to be derived from the old Welch word, "Praos," fignifying "brafs," which might easily be corrupted into Paris. The copper mines in this part of the ifland are fupposed to have been known and worked by the Romans; a pool on the top of the mountain having been diftinguished, long before the prefent works were formed, by the name of the Mine Pool. The mine of this mountain is confiderably more than a mile in circumference, and on an average 1300 men are conftantly employed in it. It has the fingular advantage of being worked in the open air; a circumftance which expedites the labour, and fecures the health of thofe employed. Abundance of vitriolic water is found in thefe works, which is fo ftrong as inftantaneoufly to turn whatever fteel or iron is dipped into it, to the colour and appearance of copper: This wateris expofed to the fun in large open troughs, and the copper quality is extracted from it by a curious procefs. Great quantities of fulphur are alfo produced, and its fublimation is carried on in various spots upon the mountain, till at laft the whole is collected into large boiling houfes, and formed into rolls of brimftone. The copper

ore

ore is then carried down to melting houfes, conftructed in the valley below, near the fea fide, where every remaining operation is performed with wonderful art and affiduity. Copper, in con fequence of the difcovery of this mine, is exported in fuch vast quantities, that it is affirmed that a difcontinuance of working it for a fingle week would raife the price throughout Europe.

LEAD. Lead is a metal for which this ifland was always famous. Our mines were very probably wrought by the Britons, but certainly by the Romans; and one of their most learned writers has affured us, that the produce was fo great as to render it neceffary to fix the quantity that fhould be raised. The Saxons followed their example, and indeed our lead mines were in all ages amongst the acknowledged fources of our national wealth, and fo they ftill remain. This metal is very abundant in South Britain, North Britain, Ireland, and the adjacent ifles. The ore appears in many different forms, and thence receives feveral names. Sometimes from its colour, it is ftyled grey, blue, or white ore: fometimes from its texture, it is called fpringy, fteel grained, and crofs grained ore; and fometimes from its pofition, flat, plated, or bellied ore; but the most common, is the diced, cubic, or teffelated ore. In fome places it has been found fo free from fpar, or other heterogeneous matter, as to be almoft pure, and this is called naked ore, and is very rich. Lead, when refined, is the fofteft of all metals, fmooth, ductile, and little, if at all, fonorous or elaftic. It is, in reference to water, as eleven to onc, and in respect to gold, as eleven to nineteen. Mines of lead are commonly on the declivity of hills, and those in this country are wrought from ten to feventy fathoms deep, cut with much labour and no small charge. The veins are very irregular, fometimes a few inches only, and fometimes feveral feet in extent. The ore is also sometimes forced out of the lead and found loofe in pretty confiderable quantities, and at fome diftance.

The operation of feparating the metal from the ore is likewife attended with trouble and expenfe, though with lefs in both than tin, iron, or copper. In the first place it is broke and beat to pieces, next washed in a running ftream, then paffed through iron fieves, and laftly carried to the furnace. This is placed on a hearth of clay or iron ftone, on which a fire is made with charcoal, and maintained with small wood. The ore is thrown on this fire, and, as the metal melts, it runs down into a receptacle prepared for it; thence, while liquid, it is lifted out in an iron ladle red hot, and being caft into a bed of fand it becomes, when cold, what they call a pig of lead. There is a wide difference in the nature and value of ores, for fome yield but thirty-five and others eighty pounds of metal from one hundred

of

of ore; but if they yield lefs than thirty-five, they are not thought worth the working, unlefs the ore is alfo known to hold filver. In fact, almost all British lead holds filver, more or lefs; but seldom in fufficient quantity to defray the expense of extracting it; fome lead yields thirty ounces of filver in a ton, fome eighteen, and fome only four ounces. The ores richest in lead, hold no filver at all worth extracting.

To enumerate all uses to which this metal is applied, either manufactured by itfelf, or in compofition with other metals, would require a feparate treatife. From lead fome other fubftances are produced, which, from the large confumption of them, may be regarded as of great value. Cerufe, or white lead, which is made by expofing thin plates of this metal to the fumes of vinegar, which is the bafis of feveral kinds of paint, ferves for many other purpofes, and is alfo of fome ufe in furgery. There is likewife a very beautiful colour made from the calx of lead, which paffes under the name of yellow ochre. Add to these minium or red lead, which is obtained by giving and continuing a certain high degree of heat to the calx of lead, in a reverberatory furnace. It is in great ufe as a fine red pigment, enters into the compofition of deficcative plaifters; and is a capital article in the commerce of the Levant. Lead has always been a very confiderable article of exportation.

Of other metals of inferior importance, it is not neceffary here to fpeak, nor of thofe which are not produced in Great Britain, further than to obferve, that the goldfmiths and filverfmiths of this country have ever been, and are still highly celebrated for their exquifite workmanship, and are frequently employed on large foreign orders.

GLASS. This ufeful and beautiful material is formed from the most ordinary fubftances, the afhes of plants and fand or pebbles. The manufacture was early known in England, but appears to have been first seriously purfued in 1557. In 1670, manufacturers were procured from Venice to teach the art of making the finer glafs, and their imperfect inftructions were greatly improved by the French refugees in 1685. At this day, no country in the world excels Great Britain in the manufactureof ordinary and flint glafs. In plate glafs, confiderable progrefs. has been made, but finer fpecimens are ftill to be procured from France.

In 1773 a fociety was incorporated for twenty-one years, by the name of The Governor and Company of British Caft Plate Glafs Manufacturers, for the purpose of carrying on and improving the manufactory, by a joint stock of eighty fhares of 500/each, and they established themfelves in Lancashire. This undertaking, although the excellence of its wares was much extolled, does VOL. III.

T

not