The third method of obtaining gold surpasses the labours of the Giants[886] even: by the aid of galleries driven to a long distance, mountains are excavated by the light of torches, the duration of which forms the set times for work, the workmen never seeing the light of day for many months together. These mines are known as “arrugiæ;”[887] and not unfrequently clefts are formed on a sudden, the earth sinks in, and the workmen are crushed beneath; so that it would really appear less rash to go in search of pearls and purples at the bottom of the sea, so much more dangerous to ourselves have we made the earth than the water! Hence it is, that in this kind of mining, arches are left at frequent intervals for the purpose of supporting the weight of the mountain above. In mining either by shaft or by gallery, barriers of silex are met with, which have to be driven asunder by the aid of fire and vinegar;[888] or more frequently, as this method fills the galleries with suffocating vapours and smoke, to be broken to pieces with bruising-machines shod with pieces of iron weighing one hundred and fifty pounds: which done, the fragments are carried out on the workmen’s shoulders, night and day, each man passing them on to his neighbour in the dark, it being only those at the pit’s mouth that ever see the light. In cases where the bed of silex appears too thick to admit of being penetrated, the miner traces along the sides of it, and so turns it. And yet, after all, the labour entailed by this silex is looked upon as comparatively easy, there being an earth—a kind of potter’s clay mixed with gravel, “gangadia” by name, which it is almost impossible to overcome. This earth has to be attacked with iron wedges and hammers like those previously mentioned,[889] and it is generally considered that there is nothing more stubborn in existence—except indeed the greed for gold, which is the most stubborn of all things. When these operations are all completed, beginning at the last, they cut away[890] the wooden pillars at the point where they support the roof: the coming downfall gives warning, which is instantly perceived by the sentinel, and by him only, who is set to watch upon a peak of the same mountain. By voice as well as by signals, he orders the workmen to be immediately summoned from their labours, and at the same moment takes to flight himself. The mountain, rent to pieces, is cleft asunder, hurling its debris to a distance with a crash which it is impossible for the human imagination to conceive; and from the midst of a cloud of dust, of a density quite incredible, the victorious miners gaze upon this downfall of Nature. Nor yet even then are they sure of gold, nor indeed were they by any means certain that there was any to be found when they first began to excavate, it being quite sufficient, as an inducement to undergo such perils and to incur such vast expense, to entertain the hope that they shall obtain what they so eagerly desire.