50 MINES OF 



CHAP. II. 



process the importance of iron tools became 

 known and the use of them adopted, the work 

 performed was still slow and excessively labo- 

 rious, till, at length, according to Diodorus \ the 

 aid of fire was introduced, which made the work 

 through the rocks much less difficult. After 

 being thus enabled to reach the ores, the workmen 

 had still to contend with the obstacles of subter- 

 ranean water, of unwholesome air, of the filling 

 the pits and passages by the earth giving way, 

 and the darkness of the mines. We know not 

 what precautions were adopted against the evil 

 arising from the air and water ; but the roofs of 

 the mines were supported by large pillars being 

 left of the natural rock, and in some parts the 

 loose stones were prevented from filling up the 

 passage by masonry. At first the only light 

 in the mines was obtained by burning chips 

 of fir-wood ; but at length lamps were in- 

 vented, which are described by a later writer, 

 Clemens Alexandrinus. Oil was burnt in them. 

 Each man had one fixed on his forehead, which 

 turned on a moveable axis, in the manner of our 

 sea compasses. The galleries were entered not 

 perpendicularly, but by the sides of the moun- 

 tains ; and the ore was brought out on the backs 

 of the men, a practice which is attributed to the 

 imperfect knowledge of mechanics in some de- 



1 Diod. book c. 



