SILVER. 



filter. The ores were exceedingly rich, and promifed at one 

 time an ample recompence to the adventurers. 



The Hurland copper-mine, near Redruth, lias produced 

 a confiderable quantity of native filvcr in a fmall vein, 

 branching from the principal vein. Some of the fibres cf 

 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 extradlcd from the 

 lead, as it yields loo ounces /i^r ton. 



Near Peranzabuia, on the north coaft of Cornwall, there 

 was a mine formerly worked clofe to the lea, which produced 

 lead-ores in various Hates, 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. 



At Comb-Martin, in North Devon, arc fome lead-mines, 

 1 which were formerly celebrated for the filver, but at pre- 

 fent they are not produftive. 



Argentiferous lead-ores are the common lead-ores of the 

 northern counties and of Wales ; they vary in t'le quantity 

 of filver they contain, from a few ounces to 40, 60, or 80 

 ounces of filver per ton. Some few rare inllanccs have oc- 

 curred in the north-welt part of Yorkfhire, of their ex- 

 ceeding the latter amount. On the average, the argenti- 

 ferous lead that is calcined to extraft the filver does not 

 contain 20 ounces per ton : by fome it has been Hated at 

 17 ounces. 



According to Lehman, there are no known lead-ores in 

 the world but what contain filver, except that of Villoch, in 

 Carinthia. (Lehman iur k-s Mines.) But according to Dr. 

 Watfon, the quantity of filver necedary to defray the expence 

 of extrafting, and the lofs of lead, was nine ounces per ton, 

 when lead was at the price of 15/. per Ion. The price of 

 lead is now 26/. per ton, and though filver be alfo advanced, 

 yet the difference in the relative prices of each, taking the 

 above as a Itandard, is fuch, that to repay the expence of ex- 

 traftion, the lead (hould 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 Ihould be forward in declaring to the 

 world the quantity of filver they contain. The proprietor 

 of the lead-mine containing filver may indeed work the fame 

 without any apprciienfion of its being taken from him under 

 the pretence of its being a royal mine ; yet the crown, and 

 perfons claiming imder it, have the right of pre-emption 

 of all the ore which may be raifcd. There was an art of 

 parliament paffed in the fixth year of William and Mary, 

 entitled. An aft to prevent difputes and controverfies concern- 

 ing royal mines. This aft declared, that every proprietor of 

 a mine of copper, tin, iron, or lead, (hould continue in pof- 

 fellion of the fame, notwithllanding its being claimed as a 

 royal mine, from its containing filver or gold ; but it is fur- 

 ther enafted, that the crown, or perfons claiming under it, 

 lliould have the privilege of purchafing all the ore which 

 fhould be raifed out of fuch mine, at the following prices, 

 when made clean and merchantable : for copper-ore, at the 

 rate of idl. per ton ; for tin-ore, except that of Devonfliirc 

 and Cornwall, \os.; for iron-ore, 40^.; and for lead-ore, 9/. 

 The ftandard price then fixed, particularly for lead, was 

 much higher than the ordinary price of the ore in which 

 there was no filver. Owing to the exillence of this aft, it 

 is probable that we are not acquainted with the quantity of 

 filver at prefent extrafted annually. We are informed, tliat 

 the value of filvcr produced by the lead-mines of colonel 

 Beaumont, in Northumberland and Durliam, is not lels than 

 4000/. Ilerling per annum ; and other large proprietors alfo 

 extraft a confiderable quantity of filver from the lead-ores in 



the northern counties. At prefent we believe that there ir 

 no filver extraftcd from the Derby (hire lead-ores. 



It appears from Hollinglhed's Clironicle, that filver was 

 formerly extrafted from lead in various parts of the ifland. 

 In the reign of Edward I. 1600 pounds weight of filver was 

 obtained in the courfe of three years, from a mine in Dovon- 

 fhire, 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 dilfc-renl 

 periods afforded great quantities of filvcr : fir Hugh Mid- 

 dleton is faid to have cleared from them two thoufand pounds 

 per month, and to have been enabled thereby to undertake 

 the great work of bringing the New River from Ware to 

 London. The lame mines yielded, in the time of Charles 1. 

 eighty ounces of filver in every ton of lead, and part of the 

 king's army was paid with this filver, which was minted at 

 Shrewfbury. Sir J. Pettie's Eday on Metal. Works. 



A mint for the coinage of Welfli filver had been previoufly 

 e(tabli(lied at Aberyftwith ; the indenture was granted to 

 Thomas Bufhel, for the coinage of half-crowns, (luUings, 

 lixpences, twopences, and pennies, and the monies were to 

 be (lamped with the ollrich feathers on both fides. In 1604 

 nearly 3000 ounces of this Welfh bullion were minted at one 

 time at the Tower. Webfter, in his Hiltory of Metals, 

 publilhed in 1671, makes mention, from his own knowledge, 

 of two places in Craven, in the Welt Riding of Yorklhire, 

 where formerly good argentiferous lead-ore had been pro- 

 cured. One of the places was Bionghile Moor, in the parilh 

 of Slaidburn ; the ore held about the value of 67 pounds of 

 filver in a ton : the other was at Skelkhornfield, in the parilh 

 of Gifburn ; it had formerly belonged to a perfon of the 

 name of Pudfey, who is fuppofed to have coined it, as there 

 were many (liiilings in that country wliich the common peo- 

 ple called Pudfey (hillings. There are fevtral fmelting- 

 houfes at Holywell, in Flintfhire, where filver is extrafted 

 from lead. According to Mr. Pennant, at one of the 

 largelt of thefe houfes in the year 1 754, more than l2,OO0 

 ounces of filver were produced, but in the fubfequent years 

 the quantity of filver appears to have confiderably diminilhed. 

 The filver extrafted from lead is fold principally to the ma- 

 nufafturers at Sheffield and Birmingham. 



The filver is extrafted from the lead by the oxydation of 

 the latter metal in a reverberatory furnace of a particular 

 conitruftion, for the admifiion of air on the furface of the 

 lead in a (tate of fufion. 



A (hallow ved'el or cupel is filled with prepared fern-aflies 

 rammed down, and a concavity cut out for the reception of 

 the lead, with an opening on one fide for the mouth of the 

 bellows, through which the air i; forcibly driven during the 

 procefs. The FreJich fmelters cover the furface of the afhei 

 with hay, and arrange fymmetrically the pieces of lead upon 

 it. when the fire is lighted, and the lead is in a (tate of 

 fufion from the reverberation of the (lame, the blalt from 

 the bellows is made to play forcibly on the furface, and in a 

 (hort time a cru(l of yellow oxyd of lead, or litharge, ii 

 formed, and driven to tlie fide of the cupel oppofite to the 

 mouth of the bellows, where a ihallow fide or aperture u 

 made for it to pafs over ; another crull of litharge is formed 

 and driven oil, and this is repeated in fucccflirfii till nearly 

 all tlie lead has been converted into litharge and driven olf. 

 The operation continues about forty hours, when the com- 

 plete feparatioii of the lead is indicated by a brilliant lu(lre 

 on the convex furface of the inelled mafs in the cupel, which 

 is occafioned by the removal of the lad crull of litharge that 

 covered the filvcr. The French introduce water ihrongh 

 a tube into the cupel, to cool the filver rapidly jnd prevci.i 

 4 Z 2 Its 



