We were conducted along a stone passage and down a spiral staircase, the weapons of our guards clanking dismally as they struck the stone steps. At the bottom of the staircase we proceeded along another passage, which was lighted by a few feeble lamps, while water trickled through the roof in such a manner as to suggest that we were passing under some canal. At the end an iron door barred the way. This the sergeant of the guard unlocked and threw open, disclosing a large room with a vaulted stone roof, lighted only by two small grated windows some twelve feet from the ground.  The atmosphere was rank, while moisture was everywhere--on the walls, floor, and even on the top of a massive oak table, the polish of which was cut and scraped till it resembled a butcher’s block.