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.