8 I'APERS, ETC. 



ploughed up. During the Operation of bringing this com- 

 mon into cultivation, the method adopted by the Romans 

 of producing the blast necessary to smelt the metal was 

 made apparent. Tvvo tunnels had been formed in the 

 side of the hill ; they were wide at one extremity, but 

 tapered off to a narrow bore at the other, where they met 

 in a point. The mouths of the Channels opened towards 

 the west, from which quartcr a prevalent wind blows in 

 this valley, and sometimes with great violence. The blast 

 received by them would, when the wind was high, be 

 poured with considerable force and effect upon the smelt- 

 ing furnaces at the extremity of the tunnels."* 



It will be observed that we have here satisfactory evi- 

 dence of the production of coal, iron, and lead, The 

 method of obtaining a blast is very remarkable ; and, as it 

 appears, that the Roman colliers extended their workings 

 to so great a depth as to penetrate even under a lake, it is 

 evident that they must have had contrivances for raising 

 the water out of the mine to the surface, either by buckets, 

 by pumps, or by the screw of Archimedes. I think we 

 may also infer that the mines were ventilated on the same 

 principle which was applied in smelting the ore, viz., by 

 the force of the wind. Pliny in his account of well-sink- 

 ing (xxxi. 28) says, that besides the principal shaft, "it 

 was the practise to sink vent-holes on each side of the 

 well, both right and left, in Order to receive and carry off 

 the noxious exhalations. Independently of these evils," 

 he continues, u the air becomes heavier from the greater 

 depth merely of the excavation, an inconvenience which 

 is remedied by keeping up a continual circulation with 



* The Roman Wall; an historical and topographical descriplion of the 

 barrier of the lower isthmus, extending from the Tyne to the Solway, 2nd 

 edition, London 1853, p. 432-434. 



