50 LEAD 



Cardiganshire aro found in clay-slates and gritstones, correspondent with or underlying 

 the lowest beds described by Sir E. Murchison in his Silurian System. 



In Shropshire we hare lead ore occurring in the original Silurian rocks, the Llandeilo 

 formation. ' In that lofty and rugged district of Shropshire which lies around the 

 village of Shelve and the Corndon mountains, and which extends west of the Stiper 

 Stones range into Montgomeryshire ' (Murchison), lead lodes are abundant. In 

 Derbyshire, in Yorkshire, in Cumberland, Northumberland, and Durham, the lead 

 mines prove the most productive in the mountain-limestone formations, although there 

 are some instances in which good lead mines have been worked in the sandstones and 

 shales. In addition to these, we have the mines in the Leadhills and at "Wanlock- 

 head, consisting chiefly of the Silurian slates, in Scotland ; Luganure, &c., in the 

 granite districts of Wicklow, Newtonards in County Down, with a few others in 

 Ireland, and the lead mines in the Silurian rocks of the Isle of Man, these are tho 

 principal districts from which our large supplies of lead ore are obtained. 



The principal lead mines at present worked in other parts of the world are the 

 following : 1. Poullaouen and Huelgoet, near Carhair in France, department of 

 Finisterre, being veins of galena, which traverse a clay-slate resting on granite. They 

 have been known for upwards of three centuries; the workings penetrate to a 

 depth of upwards of 300 yards, and in 1816, furnished 500 tons of lead per annum, 

 out of which 1,034 pounds avoirdupois of silver were extracted. 2. At Villefort and 

 Viallay, department of Lozere, are galena mines said to produce 100 tons of lead 

 per annum, 400 kilogrammes of silver (880 Ibs. avoird.). 3. At Pezey and Macot, to 

 the east of Moutiers in Savoy, a galena mine exists in talc-schist, which has produced 

 annually 200 tons of lead, and about 600 kilogrammes of silver (1,230 Ibs. avoird.). 

 4. The mine of Vedrin near Namur in the Low Countries, is opened upon a vein of 

 galena, traversing compact limestone of a transition district ; it has furnished 200 

 tons of lead, from which 385 pounds avoirdupois of silver were extracted. 5. In 

 Saxony the galena mines are so rich in silver as to make the lead almost overlooked. 

 They are enumerated under Silver Ores. 6. The lead mines of the Hartz have been 

 likewise considered as silver ones. 7- Those of Bleyberg in the Eifel are in the 

 same predicament. 8. The galena mines of Bleyberg and Villach in Carinthia are 

 in compact limestone. 9. In Bohemia to the south-west of Prague. 10. Mines of 

 Joachimsthal and Bleistadt on the southern slope of the Erzgebirge, produce argenti- 

 ferous galena. 11. There are numerous lead mines in Spain, the most important 

 being in the granite hills of Linares, upon tho southern slope of the Sierra Morcna, 

 and in the district of the small town of Caujagar. Sometimes enormous masses of 

 galena are extracted from the mines of Linares. There are also mines of galena in 

 Catalonia, Granada, Murcia, and Almeira, the ore of the last locality being generally 

 poor in silver. 12. The lead mines of Sweden are very argentiferous, and worked 

 chiefly with a view to the silver. 13. The lead mines of Daouria are numerous and 

 rich, lying in a transition limestone, which rests on primitive rocks ; their lead is 

 neglected on account of the silver. 



There have been a few lead mines in this country, which have been equally pro- 

 ductive of silver. This was especially the case with the lead mine which was 

 formerly worked near Combe Martin, and the mines formerly worked at Beer Alston 

 in Devonshire. One of the most remarkable of recent examples, is a small mine known 

 as Huel Florence, near Tavistock, from which some lead ore has been sold at upwards 

 of 90/. a ton, on account of the large quantity of silver it contained. At the conclu- 

 sion of this article some tables will be given, showing the argentiferous character of 

 the different lead-producing districts of the United Kingdom. 



Before proceeding to the consideration of the metallurgy of lead, a few brief notices 

 of tho history of lead mining may not be out of place. 



As we have already stated, mining for lead must have been one of the earliest of 

 man's subterranean labours, and at all periods of history we learn that lead mines 

 have been worked. The Romans, especially, worked lead mines in Spain, and, after 

 the conquest of this country, in many of our lead-producing districts, especially in 

 Cardiganshire, Shropshire, and Flintshire. 



Lead mining appears to have been carried on from a very early period in Alston 

 Moor, and some other of the northern districts. But in the west of England, lead 

 mining must be regarded as a somewhat recent industry. 



Borlase mentions, in 1758, that lead mines had anciently and lately been worked 

 in Cornwall, and that those most noted formerly were Penroso, Penwerty, Trevascus, 

 Eolestian, and Guarnek (Garras). He states that Penrose mines (near Helstone) had 

 been wrought for about 200 years that is, from about the middle of the sixteenth 

 century and that they had yielded tolerable profit within thirty years. The only 

 lead mine worthy of note at work in his time, was at St. Issy, near Padstow. Pryce 

 describes the lead ore of Garras, near Truro, to have been so argentiferous, that when 



