50

MINES OF

CHAP. II.

process the importance of iron tools becameknown and the use of them adopted, the workperformed was still slow and excessively labo-rious, till, at length, according to Diodorus \ theaid of fire was introduced, which made the workthrough the rocks much less difficult. Afterbeing thus enabled to reach the ores, the workmenhad still to contend with the obstacles of subter-ranean water, of unwholesome air, of the fillingthe pits and passages by the earth giving way,and the darkness of the mines. We know notwhat precautions were adopted against the evilarising from the air and water; but the roofs ofthe mines were supported by large pillars beingleft of the natural rock, and in some parts theloose stones were prevented from filling up thepassage by masonry. At first the only lightin the mines was obtained by burning chipsof 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, whichturned on a moveable axis, in the manner of oursea compasses. The galleries were entered notperpendicularly, but by the sides of the moun-tains ; and the ore was brought out on the backsof the men, a practice which is attributed to theimperfect knowledge of mechanics in some de-

1 Diod. book c.