“Take care,” said Zorzi; “it is not annealed.  It may fly.”

“Oh!” exclaimed Giovanni.  “Have you just made it?”

“Yes.”

“It is the finest glass I ever saw.  It is much better than what they had in the main furnaces the day you were hurt.  Did you not find it so yourself, in working with it?”

Zorzi began to feel anxious as to the result of so much questioning.  Whatever happened he must hide from Giovanni the fact that he had discovered a new glass of his own.

“Yes,” he answered, with affected indifference.  “I thought it was unusually good.  I daresay there may be some slight difference in the proportions.”

“Do you mean to say that my father does not follow any exact rule?”

“Oh yes.  But he is always making experiments.”

“He mixes all the materials for the main furnaces himself, does he not?” inquired Giovanni.

“Yes.  He does it alone, in the room that is kept locked.  When he has finished, the men come and carry out the barrows.  The materials are stirred and mixed together outside.”

“Yes.  I do it in the same way myself.  Have you ever helped my father in that work?”

“No, certainly not.  If I had helped him once, I should know the secret.”  Zorzi smiled.

“But if you do not know the secret,” said Giovanni unexpectedly, “how did you make this glass?”

He held up the phial.

“Why do you suppose that I made it?” Zorzi felt himself growing pale.  “The master has supplies of everything here in the laboratory and in the little room where I sleep.”

“Is there white glass here too?”

“Of course!” answered Zorzi readily.  “There is half a jar of it in my room.  We keep it there so that the night boys may not steal it a little at a time.”

“I see,” answered Giovanni.  “That is very sensible.”

He was firmly convinced that if he asked Zorzi any more direct question, the answer would be a falsehood, and he applauded himself for stopping at the point he had reached in his inquiries.  For he was an experienced glass-maker and was perfectly sure that the phial was not made from Beroviero’s ordinary glass.  It followed that Zorzi had used the precious book, and Giovanni inferred that the rest was a lucky accident.

“Will you sell me one of those beautiful things you have in the oven?” Giovanni asked, in an insinuating tone.

Zorzi hesitated.  The master had often paid him a fair price for objects he had made, and which were used in Beroviero’s house, as has been told.  Zorzi did not wish to irritate Giovanni by refusing, and after all, there was no great difference between being paid by old Beroviero or by his son.  The fact that he worked in glass, which had been an open secret among the workmen for a long time, was now no secret at all.  The question was rather as to his right, being Beroviero’s trusted assistant, to sell anything out of the house.