Metals. MINER 
near Deutfchlipfch in Hungary, and nearNagyag in Tran- 
fylvania; confiding of gold alloyed with common anti¬ 
mony. Its furface is fometimes ftriate like the web of a 
feather. 
8. Aurum rufefcens, red gold, or pfeudogalena: of a 
reddifli colour, emitting fulphurous flames when heated 
to whitenefs. Found near Nagyag in Tranfylvania; la¬ 
mellar, of a femimetallic luftre; and contains zink, oxyd 
of iron, and fulphur, befides the gold. 
9. Aurum cinereum, or grey gold : hardifli, brittle, 
compafit, of a yellowifli fteel colour ; emitting fulphurous 
flames and arfenical fumes when heated to whitenefs. 
Found near Nagyag in Tranfylvania ; and refembles in 
appearance grey copper-ore. It contains an alloy of fil- 
ver mixed with fulphur and arfenic. 
10. Aulum albidum, or white gold: whitifh, yellowifli 
internally ; fibrous, emitting fulphurous flames and arfe¬ 
nical fumes when heated to whitenefs. Found in the 
gold mines of Nagyag in Traniylvania; and contains, 
befides the gold, fulphur, arlenic, and iron. 
11. Aurum virefcens, or green gold: of a greenifh- 
gold colour and rather obfcure luftre, and minutely-gra¬ 
nular texture. Found near Nagyag in Traniylvania im¬ 
bedded in quartz; and, befides the gold, contains fulphur, 
iron, copper, and manganefe. It is more than probable 
that fome of thefe laft fpecies are ores of Tellurium. 
12. Aurum pyriticorum, or gold pyrites : of a gold- 
yellow colour, emitting fulphurous flames when made 
white hot. Found in the gold-mines of Sumatra, New 
Spain, Hungary, Sweden, and Tranfylvania; fometimes in 
a cryftallized form, and confifts of gold combined with 
fulphur by means of iron. 
Argentum, Silver.—Of a white colour, not tarniftied 
by the air; hard and tenacious, fonorous, exceedingly 
malleable and duftile ; fpecific gravity before hammering, 
io - 478. Melting when perfeftly red-hot, and its bril¬ 
liancy much increafed. Soluble in nitric acid, giving no 
colour to the folution; and may be precipitated from it 
by copper, iron, or zinc. 
The molt productive filver-mines in the world are thofe 
of South America and New Spain. Thofe of Peru, for 
many years after its conqueft by the Spaniards, yielded 
the greateft quantity of filver ; but at prefent the mines 
of Mexico are the richeft. The mines of America furnilh 
both filver and gold ; and, in making an eftimate of their 
richnefs, we mult take an account of each of thefe metals. 
The following table, given by M. Humboldt, will (how 
the diftribution of thefe mineral treafures in the different 
parts of the new world; the chiliogramme being 2lbs. 
joz. 5<ar. avoirdupois, or rather more than 2 lbs. 8 oz. 
troy. 
Gold. Silver. 
Viceroyalty of Peru - - - 782 140,478 
Viceroyalty of New Spain - - 1,609- 537,512 
Capitania of Chili - 2,807 6,827 
Viceroyalty of Buenos Ayres - 506 110,764 
Viceroyalty of Grenada - - 4,714 - 
Chiliogrammes 17,291 995,581 
The above was the annual produce of the different dil- 
trifts at the beginning of the nineteenth century ; from 
which it appears, that the total weight of the precious 
metals from all the mines in America, reduced to Eng- 
lilh pounds troy, is 45,580 lbs. of gold annually, and the 
enormous quantity of 145,00c lbs. of filver; equal in 
weight to one-third of the tin produced by the mines in 
Europe. Dr. Smith, in his Wealth of Nations, values the 
gold and filver annually exported into Cadiz and Lifbon 
at only fix millions fterling, including not only the re- 
giftered gold and filver, but that which may be luppofed 
to be lmuggled. This eftimate is only two-fifths of the 
real annual amount. 
The mountain of Pctofi (in Peru) has furniflied, fince 
A L O G Y. Metals. 483 
its difcovery in 1545, a mafs of filver equal in value to 
234,093,8401. fterling: The mountain is 18 miles in cir¬ 
cumference : it is compofed of (late, but has a conical 
covering of porphyry, which gives it the form of a fugar- 
loaf, or bafaltic hill; it rifes 697 toiles, or 480 yards, above 
the furrounding plain. The richnefs of the veins has di- 
miniflied, as they have been worked to greater depths. 
At the furface of the earth, the veins of Rica, Centeno, 
and Mendifta, which traverfe primitive (late, were filled 
with native filver and filver-ores throughout their whole 
extent. Thefe metallic mafi’es rofe in ridges or crefts 
above the furface, the (ides of the vein having been de- 
ftroyed either by w-ater or by fome other caufe. In 1545, 
minerals containing from 80 to 90 marcs of filver per 
quintal were common. In the year 1574, according to 
Acofta, the average richnefs of the ore was eight or nine 
marcs per quintal. In 1607, the mean wealth of the ores 
was not more than an ounce and a half to the quintal. 
The ores are now extremely poor, and it is on account of 
their abundance alone that the works are (fill in a flou- 
rifliing (late; (fee Mexico, p. 306.) for, from 1574 to the 
year 1789, the mean quantity of filver in the ores has di- 
miniflied in the proportion of 170 to 1 ; while the abfo- 
lute quantity of filver extradited from the mines of Potoll 
has only diminiflied in the proportion of 4 to 1. 
About fix miles from Pafco is the mountain Jauvichora, 
diftinguiihed by the name of the Silver Mountain. It is 
about half a mile in diameter, and only about thirty yards 
in depth : it is compofed of brown iron-ftone, which is 
interfperfed with pure filver. This (tone does not yield 
more than nine marcs of filver in 500 lbs. but there is a 
friable white clay met with in the middle of this mafs of 
ore, which yields from 200 to 1000 marcs of filver in every 
50 cwt. The mountain is penetrated in all directions, 
without any attention to fecurity ; fo that it is expedited 
it may fall in, in the courfe of a few years. According to 
Helms, this mountain yields annually 200,000 marcs of 
filver. 
The veins of filver in Potofi are in (late, which Hum¬ 
boldt conliders as primitive : this (late is covered with a 
clay porphyry, containing garnets. The mines of Gualga- 
yoc, in Peru, are in the alpine lime-ftone. The veins which 
furnilh nearly all the filver’exported from Vera Cruz are 
in (late, porphyry, grauwacke, and alpine lime-ftone : the 
principal of thefe veins are thofe of Guanaxto, Zacatecas, 
and Catoree. The vein of Guanaxto yields more than 
one-fourth of the filver of Mexico, and a fixth part of the 
total produce of America. This vein is, in fome parts, 
150 feet in width, including the branches, and has been 
wrought from Santa Ifabella and San Bruno to Buena- 
Velfa, a length of 42,000 feet. 
The mod celebrated mines in Mexico are elevated from 
6000 to 9000 feet above the level of the fea. In the An¬ 
des, the mines of Potofi, Ocuro, Pas, Pafco, and Gual- 
gayoc, are in regions higher than the ioftieft fummits of 
the Pyrenees. A mafs of rich filver-ore has been dilco- 
vered near the (mail town of Micuicampa, at the abfoiute 
height of 13,450 feet. The great elevation of the Mex¬ 
ican mines is peculiarly advantageous to the working of 
them, as the climate is temperate, and favourable to ve¬ 
getation and cultivation. The part of the Mexican moun 
tains which at prefent contains the greateft quantity of 
filver, lies between the twenty-rirlf and twenty-fourth de¬ 
grees of latitude ; and it is not a little remarkable, that 
the metallic wealth of Peru (hould be placed at an almoft 
equal latitude on the other fide of the equator. In the 
vaft extent which feparates the mines of La Pas and Potofi 
from thofe of Mexico, there are no others which throw 
into circulation a great mafs of the precious metals, but 
thofe of Pafco and Chota. The ifthmus of Panama 
and the mountains of Guatimala contain, for a length of 
600 leagues, vaft trafts of ground, in which no vein has 
hitherto been worked with fuccefs. The province of 
Quito, and the eaftern part of the kingdom of New Gre¬ 
nada, from the eighth degree of Couth latitude to the fe- 
venth 
