This day Carlo set himself to solve the mystery of his visitor’s lightning disappearances—_Anglicè_, to find a rat-hole. Fingering, in the gloom, along the joint of floor and wall, he presently discovered a jagged hole which he thought might explain. Without removing his hand, he called softly: ’Topo! Messer Topo!’ Instantly a little sharp snout, tipped with a chilly nose, touched him and withdrew. He stood up, as the key turned in the lock once more. This time it was Messer Jacopo himself who entered, while his bulldogs watched at the door. He came to bring the prisoner a volume of Martial, which Carlo had once had recommended to him, and of which he had since bethought himself as a possible solace in his gloom. The Provost Marshal advanced, with the book in his hand, and seeing his captive’s occupation, as he thought, paused, with a dry smile on his lips. Then, with his free palm, he caressed the wall thereabouts. ’Strong masonry, Messer,’ he said; ’good four feet thick. And what beyond? A dungeon, deadlier than thine own.’ Carlo laughed. ’A heavy task for nails, old hold-fast, sith you have left me nothing else. _Lasciate ogni speranza_, hey, and all the rest? I know, I know. Yet, look you, there should have been coming and going here once, to judge by the tokens.’ He signified, with a sweep of his hand, a square patch on the stones, roughly suggestive of a blocked doorway, wherein the mortar certainly appeared of a date more recent than the rest. The other made a grim mouth. ’Coming, Messer,’ he said; ’but little going. Half-way he sticks who entered, waiting for the last trump. He’ll not move until.’ Carlo recoiled. ’There’s one immured there?’ ’Ay, these ten years——’ And the wooden creature, laying the book on the table, stalked out like an automaton. He left the prisoner gulping and staring. Here, in sooth, was food for his fancy, luckily no great possession. But the horror bit him, nevertheless. Presently he took up the book—tried to forget himself in it. He found it certainly very funny, and laughed: found it very gross, and laughed—and then thought of Bernardo, and frowned, and threw the thing into a corner. Then he started to his feet and went up and down, nervously, with stealthy glances to the wall. Haunted! No wonder he was haunted. Did it sob and moan in there o’ nights, beating with its poor blind hands on the stone? Did it—— A thought stung him, and he stopped. The rat! Its run broke into that newer mortar, penetrated, perhaps, as far as the buried horror itself. Was _there_ the secret of the music? Was it wont, that hapless spectre, putting its pallid lips to the hole, to sigh nightly through it its melodious tale of griefs? He stood gnawing his thumb-nail.