robe made entirely of gold wire, without any mixture whatsoever.

What is related of the extreme fmallness of gold and filver, when reduced into wire, would feem incredible, if not confirmed by daily experience. I fhall only copy here what I find in the memoirs of the academy of An. 1718 sciences upon this head.

We know, fay thofe memoirs, that goldwire is only filver-wire gilt. By the means of the engine for drawing wire, a cylinder of filver, covered with leaf-gold, being extended, becomes wire, and continues gilt to the utmost length it can be drawn. It is generally of the weight of forty-five marks; its diameter is an inch and a quarter French, and its length almost two and twenty inches. Mr. Reaumur proves, that this cylinder of filver, of two and twenty inches, is extended by the engine to thirteen million, nine hundred and fixty three thousand, two hundred and forty inches, or, one million, one hundred and fixty three thousand, five hundred and twenty feet; that is to say, fix hundred and thirty four thoufand, fix hundred and ninety two times longer than it was, which is very near ninety feven leagues in length, allowing two thousand perches to each league. This wire is fpun over filk-thread, and before fpun is made flat from round as it was, when first drawn, and in flatting generally lengthens one feventh at least; fo that its firft length of twenty two inches, is changed into that of an hundred and eleven leagues. But this wire may be lengthened a fourth in flatting, inftead of a feventh, and in confequence be fixfcore leagues in extent. This fhould feem a prodigious extenfion, and yet is nothing.

The

Lib. 33.

c. 3.

The cylinder of filver of forty five marks, and twenty two inches length, requires only to be covered with one ounce of leaf-gold. It is true, the gilding will be light, but it will always be gilding; and though the cylinder in paffing the engine attains the length of an hundred and twenty leagues, the gold will ftill continue to cover the filver without variation. We may fee how exceedingly small the ounce of gold, which covers the cylinder of filver of forty-five marks, muft become, in continuing to cover it throughout fo vaft an extent. Mr. Reaumur adds to this confideration, that it is eafy to distinguish, that the filver is more gilt in fome than in other places; and he finds, by a calculation of wire the moft equally gilt, that the thickness of the gold is 88 th. of a line, or twelfth part, of an inch; fo enormous a fmallness, that it is as inconceivable to us, as the infinite points of the geometricians. It is, however, real, and produced by mechanical instruments, which, though ever fo fine to our fenfes, muft ftill be very grofs in fact. Our understanding is loft and confounded in the confideration of fuch objects and how much more in the infinitely Small of God!

I

ELECTRUM.

It is neceffary to obferve, fays Pliny, whom copy in all that follows, that in all kinds of gold there always is fome filver, more or less: fometimes a tenth, fometimes a ninth or an eighth. There is but one mine in Gaul from whence gold is extracted, that contains only a thirtieth part of filver, which makes it far more valuable than all others. This gold is called Albicratenfe, of Albicrate, (an antient

place in Gaul near Tarbæ.) There were feveral mines in Gaul, which have been fince either neglected or exhausted. Strabo mentions fome Strab. 1. 4. of them, amongst which are thofe of Tarbæ, P. 190. that were, as he fays, very fruitful in gold. For without digging far, they found it in quantities large enough to fill the palm of the hand, which had no great occafion for being refined. They had alfo abundance of gold-duft, and Bados gold in grains of equal goodness with the other.

To the gold, continues Pliny, which was found to have a fifth part of filver in it, they gave the name of ELECTRUM. (It might be called white gold, because it came near that colour, and is paler than the other.) The most antient people seemed to have fet a great value upon it. Homer, in his defcription of Mene- Odyfs. 1.4. laus's palace, fays, it fhone univerfally with v. 71. gold, electrum, filver, and ivory. The electrum has this property peculiar to it, that it brightens much more by the light of lamps than either gold or filver.

SECT. IV.

Silver-mines.

SILVER-MINES, in many respects, re- Plin.1.33. femble those of gold. The earth is bored, c. 6. and long caverns cut on the right or left, according to the courfe of the vein. The colour of the metal does not enliven the hopes of the workmen, nor the ore glitter and fparkle as in the others. The earth which contains the filver is fometimes reddish, and fometimes of an ash colour; which the workmen diftinguish by ufe. As for the filver, it can be only refined

by

*

by fire, with lead, or with pewter-ore. This
ore is called galena, and is found commonly in
the veins of filver-mines. The fire only fepa-
rates thefe fubftances; the one of which it re-
duces into lead or pewter, and the other into
filver; but the laft always fwims at top, be-
cause it is lighteft, almost like oil upon water.

There were filver-mines in almost all the
provinces of the Roman empire. That metal
was found in Italy near Vercellæ; in Sardinia,
where there was abundance of it; in feveral
places of the Gauls; even in Britain; in Alface,
witnefs Strafburgh, which took its name Ar-
gentoratum, as Colmar did Argentaria, from it;
in Dalmatia and Pannonia, now called Hun-
gary; and laftly, in Spain and Portugal, which
produced the finest gold.

What is moft furprizing in the mines of Spain, is, that the works, began in them by Hannibal's orders, fubfift in our days, fays Plin. ibid. Pliny; that is to fay, above three hundred years, and that they ftill retain the names of the firft discoverers of them, who were all Carthaginians. One of thefe mines, amongst the rest, exifts now, and is called Bebulo. It is the fame from which Hannibal daily extracted three hundred pounds of filver, and has been ran fifteen hundred paces in extent, and even through the mountains, by the || Accitanian people; who, without refting themfelves either by night or day, and fupporting themfelves only by the aid of their lamps, have drawn off all the water

from them. There are alfo veins of filver, difcovered in that country, almost upon the furface of the earth.

For the reft, the antients easily knew when they were come to the end of the vein, which was when they found allum; after that they fearched no farther though lately, (it is still Pliny who speaks) beyond the allum, they have found a white vein of copper, which served the workmen as a new token, that they were at the end of the vein of filver.

The discovery of the metals we have hitherto spoken of, is a wonder we can never sufficiently admire. There was nothing more hidden in nature than gold and filver. They were buried deep in the earth, mingled with the hardest stones, and in appearance perfectly useless; the parts of thefe precious metals were fo confounded with foreign bodies, fo imperceptible from that mixture, and fo difficult to feparate, that it did not seem poffible to cleanse, collect, refine, and apply them to their uses. Man, however, has furmounted this difficulty, and by experiments has brought his first difcoveries to fuch perfection, that one would imagine gold and filver were formed from the first in folid pieces, and were as easily distinguished as the flints, which lie on the furface of the earth. But was man of himself capable of making such discoveries? Cicero * fays, in exprefs terms, that God in vain had formed gold, filver, copper, and iron, in the bowels of the earth, if he had not vouchfafed to teach man the means, by which he might come at the veins, that conceal those precious metals.

*Aurum & argentum, æs ferrum fruftrà natura divina genuiffet, nifi eadem docu

iffet quemadmodum ad eorum venas perveniretur. De Divinat. I. 1. n. 116.

SECT.