“Yes,” answered Giovanni, enjoying his triumph.  “I pointed out that when I had last come, there had been no white glass in the furnace.  He answered that as one of the experiments had produced a beautiful red colour which he thought must be valuable, he had removed the crucible.  He also showed me a specimen of it.”

“Is it here?” asked Beroviero anxiously.  “Where is it?”

Giovanni took the specimen from the table, for Zorzi had left it lying there, and he handed it to his father.  The latter took it, held it up to the light, and uttered an exclamation of astonishment and anger.

“There is only one way of making that,” he said, without hesitation.

“Yes,” Giovanni answered coolly.  “I supposed it was made according to one of your secrets.”

A quick look was the only reply to this speech.  Giovanni continued.

“I asked him to sell me the piece of glass he had been making when he came in, and at first he pretended that he was not sure whether you would allow it, but at last he took a piece of gold for it, and I was to have it as soon as it was annealed.  When you see it, you will understand why I was so anxious to get it.”

“Where is it?” asked the old man.  “Show it to me.”

Giovanni went to the other end of the annealing oven, and came back a moment later carrying the iron tray on which stood the pieces Zorzi had made on the previous morning.  Beroviero looked at them critically, tried their weight, and noticed their transparency.

“That is not my glass,” he said in a tone of decision.

“No,” said Giovanni, “I saw that it was not your ordinary glass.  It seems much better.  Now Zorzi must have made it in a new crucible, and if he did, he made it with some secret of yours, for it is impossible that he should have discovered it himself.  I said to myself that if he had made it, and the red glass there, he must have opened the book which you had buried together in this room, and that there was only one way of hindering him from learning everything in it, and ruining you and us by setting up a furnace of his own.”

Beroviero was looking hard at Giovanni, but he was now thoroughly alarmed for the safety of his treasured manuscript, and listened with attention and without any hostility.  The proofs seemed at first sight very strong, and after all Zorzi was only a Dalmatian and a foreigner, who might have yielded to temptation.

“What did you do?” asked Beroviero.

Giovanni told him the truth, how he had written a letter to the Governor, and had seen him in person, as well as Jacopo Contarini.

“Of course,” Giovanni concluded, “you know best.  If you find the book as you and he hid it together, he must have learned your secrets in some other way.”

“We can easily see,” answered old Beroviero, rising quickly.  “Come here.  Get the crowbar from the corner, and help me to lift the stone.”