MINERALOGY. 279 



procurable, but it is understood that the wad-mine has not been in 

 a prosperous condition of late years. It is generally known at the 

 present day that the name black lead is erroneous. The substance 

 scf called being carburet of iron, consisting of the same elements 

 as steel, but with the proportions of these reversed — the one 

 being formed of iron with a small percentage of carbon or char- 

 coal, and the other of carbon, with a small percentage of iron. 



Lead. — No mineral production is so universally distributed 

 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 numer- 

 ous 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 

 combination 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 here smelted and 

 separated 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 

 being condensed in long chimneys which run up the sides of 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 Hel- 

 vellyn. As at Coniston, the excavations in Patterdale are all at 

 considerable elevations, with the different 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 man had to penetrate was Jiint. 



The almost universal occurrence of this metal has led to almost 

 equally universal attempts throughout the Lake District to 

 establish lead-mines ; and in nearly every instance lead has been 



