X^meralojgg* 359 



neous. The substance so called being carburet of iron, 

 consisting of the same elements as steel, but with the pro- 

 portions of these reversed — the one being formed of iron, 

 with a small percentage of carbon of charcoal, and the 

 other of carbon, with a small percentage of iron. 



Lead. — No mineral production is so universally distri- 

 buted throughout the hill-country as lead. There is scarcely 

 a valley or even a hill that does not exhibit some indication 

 of the presence of this metal. Like copper, it has its chief 

 habitat in the green slate-rock, but it occurs also in other 

 formations. Of the numerous lead mines in the country 

 those at Greenside, in Patterdale, setting aside Alston as out 

 of our range, are by far the most extensive and successful. 

 For many years large quantities of lead and a considerable 

 amount of silver have been obtained from these mines ; the 

 ore being the common sulphuret, holding in combinations, 

 besides silver, various other substances, the most important 

 of these being arsenic. Contrary to the custom at the other 

 great mines of the district, the ores are smelted and sepa- 

 rated on the spot ; the silver being taken out by a very simple 

 and ingenious process, the principle of which depends upon 

 the different temperatures at which the two metals are fusible, 

 while the arsenic is separated by sublimation, the fumes be- 

 ing condensed in long chimneys which run up the sides of 

 the mountains. It may be remembered that an eminent 

 Scottish professor nearly perished by suffocation in 1857, 

 from having broken into one of these chimneys while 

 ascending Helvellyn. As at Coniston, the excavations in 

 Patterdale are all at considerable elevations, with the dif- 

 ferent workings at different altitudes ; as there also the ore is 

 embedded in very hard rock, so much so that we have 

 heard one of the managers say that the softest material his 

 men had to penetrate was flint. 



