He searched Zorzi’s room carefully, but could find nothing.  An earthen jar containing broken white glass stood in one corner.  The narrow truckle-bed, with its single thin mattress and flattened pillow, all neat and trim, could not have hidden anything.  On a line stretched across from wall to wall a few clothes were hanging—­a pair of disconsolate brown hose, the waistband on the one side of the line hanging down to meet the feet on the other, two clean shirts, and a Sunday doublet.  On the wall a cap with a black eagle’s feather hung by a nail.  Here and there on the white plaster, Zorzi had roughly sketched with a bit of charcoal some pieces of glass which he had thought of making.  That was all.  The floor was paved with bricks, and a short examination showed that none of them had been moved.

Giovanni turned back into the laboratory, stood a moment looking disconsolately at the big stone which it had cost him so much fruitless labour to move, and then passed round by the other side of the furnace, along the wall against which the bench and the easy chair were placed.  His eye fell on Marietta’s silk mantle, which lay as when it had slipped down from her shoulders, the skirts of it trailing on the floor.  His brows contracted suddenly.  He came nearer, felt the stuff, and was sure that he recognised it.  Then he looked at it, as it lay.  It had the unmistakable appearance of having been left, as it had been, by the person who had last sat in the chair.

Two explanations of the presence of the mantle in the laboratory suggested themselves to him at once, but the idea that Marietta could herself have been seated in the chair not long ago was so absurd that he at once adopted the other.  Zorzi had stolen the mantle, and used it for himself in the evening, confident that no one would see him.  To-night he had been surprised and had left it in the chair, another and perhaps a crowning proof of his atrocious crimes.  Was he not a thief, as well as a liar and an assassin?  Giovanni knew well enough that the law would distinguish between stealing the art of glass-making, which was merely a civil offence, though a grave one, and stealing a mantle of silk which he estimated to be worth at least two or three pieces of gold.  That was theft, and it was criminal, and it was one of many crimes which Zorzi had undoubtedly committed.  The hangman would twist the rest out of him with the rack and the iron boot, thought Giovanni gleefully.  The Governor should see the mantle with his own eyes.

Before he went away, he was careful to fasten the window securely inside, and he locked the door after him, taking the key.  He carried the brass lamp with him, for the corridor was very dark and the night was quite still.

Pasquale was seated on the edge of his box-bed in his little lodge when Giovanni came to the door.  He was more like a big and very ugly watch-dog crouching in his kennel than anything else.

“Let no one try to go into the laboratory,” said Giovanni, setting down the lamp.  “I have locked it myself.”