if a mine was deserted for a while and then re-opened, it was sure to be found more productive than it was previously.[1029] The fact seems to be simply that the supply is inexhaustible, since even now Spain furnishes more than half the lead that is consumed by the rest of Europe. Besides the ordinary metals, Spain was capable of yielding an abundance of quicksilver;[1030] but this metal seems not to have attracted the attention of the Phoenicians, who had no use for it. The methods employed by the Phoenicians to obtain the metals which they coveted were not, on the whole, unlike those which continue in use at the present day. Where surface gold was brought down by the streams, the ground in their vicinity, and such portions of their beds as could be laid bare, were searched by the spade; any earth or sand that was seen to be auriferous was carefully dug out and washed, till the earthy particles were cleared away, and only the gold remained. Where the metal lay deeper, perpendicular shafts were sunk into the ground to a greater or less depth--sometimes, if we may believe Diodorus,[1031] to the depth of half a mile or more; from these shafts horizontal adits were carried out at various levels, and from the adits there branched lateral galleries, sometimes at right angles, sometimes obliquely, which pursued either a straight or a tortuous course.[1032] The veins of metal were perseveringly followed up, and where faults occurred in them, filled with trap,[1033] or other hard rock, the obstacle was either tunnelled through or its flank turned, and the vein still pursued on the other side. As the danger of a fall of material from the roofs of the adits and galleries was well understood, it was customary to support them by means of wooden posts, or, where the material was sufficiently firm, to arch them.[1034] Still, from time to time, falls would occur, with great injury and loss of life to the miners. Nor was there much less danger where a mountain was quarried for the sake of its metallic treasures. Here, too, galleries were driven into the mountain-side, and portions of it so loosened that after a time they detached themselves and fell with a loud crash into a mass of _débris_.[1035] It sometimes happened that, as the workings proceeded, subterranean springs were tapped, which threatened to flood the mine, and put an end to its further utilisation. In such cases, wherever it was possible, tunnels were constructed, and the water drained off to a lower level.[1036] In the deeper mines this, of course, could not be done, and such workings had to be abandoned, until the invention of the Archimedes’ screw (ab. B.C. 220-190), when the water was pumped up to the surface, and so got rid of.[1037] But before this date Phoenicia had ceased to exist as an independent country, and the mines that had once been hers were either no longer worked, or had passed into the hands of the Romans or the Carthaginians.