486 Metals. MINERALOGY. Metals. 
was exhaufted, after which the fearch to recover the vein 
proved fruitlefs, and fince that time no filver-mines have 
been worked in that country. The fdver-ores at Alva 
were accompanied with copper, lead, and cobalt, ores, 
with a matrix of calcareous fpar, and fulphat of barytes. 
It is fuppofed by Dr. Millar that the veins traverfe rocks 
of argillaceous porphyry. 
Cornwall and Devonlhire yield the richeft argentiferous 
lead-ores of any part of Great Britain ; but the quantity 
of thefe ores is fmall. In the former county a ftiiail quan¬ 
tity of native filver, with other filver-ores, have been oc- 
calionally found. The following account of the prefent 
ftate of the filver-mines in thefe counties, is furnilhed by 
Mr. Mawe, author of Travels in Bralil, who vifited them 
in the fummer of 1815. 
From the lead-mines of Ben-Alften, in Devonfhire, a 
large quantity of lilver has been extrafted. The vein is 
fituated in killas, a kind of date ; and is filled chiefly with 
fluor fpar and galena. It has been worked to the depth 
of no fathoms : the lilver extrafted from the north and 
fOuth vein averages about 70 ounces to the ton of lead. 
Another vein, running in a more eallerly and wefterly 
direftion, fituated in the fame killas, produces 170 ounces 
of lilver in the ton of lead. The vein is worked under 
the river Tamar: it was difcovered in the year 1811. 
Thefe mines are of confiderable importance ; during the 
laft fix weeks, the filver extracted from the lead procured 
here exceeded fix thoufand ounces. About four miles to 
the fouth-eaft of Callington is a filver-mine of another 
defcription : the vein is fituated in afimilar rock of killas, 
or chlorite date. The vein was firft worked for copper ; 
but native filver and lead-ore were difcovered in it. The 
mine is called Huel Jewel: the thicknefs of the vein 
rarely exceeds three or four inches. In many of the ca¬ 
vities were found a confiderable quantity of capillary na¬ 
tive filver, with galena, red filver-ore, and fulphuret of 
lilver. The ores were exceedingly rich, and promifed at 
one time an ample recompence to the adventurers. 
Near Peranzabula, on the north coaft of Cornwall, there 
was a mine formerly worked clofe to the fea, which pro¬ 
duced lead-ores in various dates, and a portion of horn- 
filver, fine fpecimens of which are in various cabinets. 
Mr. Mawe found fome fpecimens of this rare mineral 
among the refufe of the mine. The Hurland copper- 
mine near Redruth, has produced a confiderable quantity 
of native filver in a fmall vein, branching from the prin¬ 
cipal vein. Some of the fibres of the filver were more than 
four inches long. There is a lead-mine near Truro 
worked at this time, and a confiderable quantity of filver 
is extrafted from the lead, as it yields 100 ounces per ton. 
A fpecimen of filver, lent from Truro,^by Mr. Arthur 
Penrofe, affay-mailer, was very lately (Aug. 1816.) laid 
before the committee of the Britifli Mufeum. It con¬ 
fided of a cobalt-ltone, intimately combined with capil¬ 
lary or filiform filver, weighing upwards of 124-lbs. The 
committee pronounced it to be the larged fpecimen of 
native filver they had ever feen. 
Argentiferous lead-ores are the common lead-ores of 
the northern counties and of Wales ; they vary in the 
quantity of filver they contain, from a few ounces to 40, 
60, or 80, ounces of filver per ton. Some few rare in¬ 
dances have occurred in the north-wed part of Yorkfliire, 
of their exceeding the latter amount. On the average, 
the argentiferous lead that is calcined to extraft the filver 
does not contain 20 ounces per ton : by fome it has been 
dated at 17 ounces,: According to Lehman, there are no 
known lead-ores in the world but what contain filver, ex¬ 
cept that of Villoch in Carinthia. But, according to Dr. 
Watfon, the quantity of filver necefiary to defray the 
expenfe of extracting, and the lofs of lead, was nine 
ounces per ton, when lead was at the price of 15I. per ton. 
The price oflead is now 26I. per ton j and, though filver 
be alfo advanced, yet the difference in the relative prices 
of each, taking the above as a dandard, is fuch, that, to 
repay the expenfe of extraction, the lead ffiould contain 
about fifteen ounces of filver in every ton. It is not to 
be expefted that the proprietor of any lead-mines rich 
in filver flrould be forward in declaring to the world the 
quantity of lilver they contain. The proprietor of the 
lead-mine containing filver may indeed work the fame 
without any appfehenfion of its being taken from him 
under the pretence of its being a royal mine; yet the 
crown, and perfons claiming under it, have the right of 
pre-emption of all the ore w'hich may be railed. There 
was an aCt of parliament palled in the fixth year of Wil¬ 
liam and Mary, entitled, An aft to prevent difputes and 
controverlies concerning royal mines. This aft declared, 
that every proprietor of a mine of copper, tin, iron, or 
lead, fhould continue in poffefiion of the fame, notwith- 
danding its being claimed as a royal mine, from its con¬ 
taining filver or gold ; but it is further enafted, that the 
crown, or perfons claiming under it, fhould have the pri¬ 
vilege of purchaling all the ore which fhould be railed, 
out of fuch mine, at the following prices, w'hen made 
clean and merchantable : for copper-ore, at the rate of 
1 61 . per ton ; for tin-ore, except that of Devonlhire and 
Cornwall, 40s. for iron-ore, 40s. and for lead-ore, 9I. 
The dandard price then fixed, particularly for lead, w’as 
much higher than the ordinary price of the ore in which 
there was no filver. Owing to the exiltence of this aft, it 
is probable that we are not acquainted with the quantity 
of filver at prefent extrafted annually. We are informed, 
that the value of filver produced by the lead-mines of 
colonel Beaumont, in Northumberland and Durham, is 
not lels than 4000I. derling per annum ; and other large 
proprietors alfo extraft a confiderable quantity of filver 
from the lead-ores in the northern counties. At prefent 
w-e believe that there is no filver extrafted from the Der- 
bydiire lead-ores. 
It appears from Hollingfhed’s Chronicle, that filver 
was formerly extrafted from lead in various parts of the 
illand. In the reign of Edward I. 1600 pounds weight of 
filver was obtained in the courfe of three years, from a 
mine in Devonlhire, which had been difcovered towards 
the beginning of his reign ; this mine is called a filver- 
mine by the old writers, but it appears to have been a 
mine of lead that contained filver. The lead-mines in 
Cardiganfliire have at different periods afforded great 
quantities of filver; fir Hugh Middleton is laid to have 
cleared from them 2000I. per month, and to have been 
enabled thereby to undertake the great work of bringing 
the New River from Ware to London. The fame mines 
yielded, in the time of Charles I. eighty ounces of filver 
in every ton of lead $ and part of the king’s army w'as paid 
with this filver, w'hich was minted at Shrewlbury. (Sir J. 
Pettie’s Effay on Metal. Works.) A mint for the coin¬ 
age of Wellh filver had been previoully eftablilhed at 
Aberyllwith; the indenture was granted to Thomas 
Bulhel, for the coinage ofhalf-crowns, lliillings, fixpences, 
twopences, and pennies; and the moneys were to be 
ftamped with the oftrich-feathers on both fides. In 1604 
nearly 3000 ounces of this Wellh bullion were minted 
at one time at the Tower. Webfter, in his Hiftory of 
Metals, publilhed in 1671, makes mention, from his own 
knowledge, of two places in Craven, in the Weft Riding 
of Yorklhire, where formerly good argentiferous lead-ore 
had been procured. One of the places was Bronghite 
Moor, in the parilh of Slaidburn ; the ore held about the 
value of 67 pounds of lilver in a ton : the other was at 
Skelkhornfield, in the parilh of Gilburn ; it had formerly 
belonged to a perfon of the name of Pudfey, who is fup- 
poled to have coined it, as there were many Ihillings in 
that country which the common people called Pudley- 
lhillings. There are feveral fmelting-houfes at Holywell, 
in Flintlhire, where filver is extrafted from lead. Ac¬ 
cording to Mr. Pennant, at one of the largeft of thefe 
houles, in the year 1754, more than 12,000 ounces of 
filver were produced; but in the fubfequent years the 
quantity appears to have conliderably diminilhed. The 
lilver extrafted from lead is fold principally to the manu- 
fafturers 
