"There," explained Don Esteban, pointing to an upper shelf, "is where the box stood."
"Oh, it was not a large box, then!" said Adrian.
"Oh, no! Not more than eight or nine inches cube."
The boy examined the vault carefully by the light of a gas jet.
"There seems no way that any one could have entered except by the door," said Donald.
"None whatever!"
"You are sure there is no opening in the ceiling?"
"Absolutely."
Don Esteban led the boys out and locked the door of the vault.
"Well," declared Donald as they came out into the patio after finishing their inspection, not only of the vault but of the rest of the office, "I guess we had better go home and study over the matter a little. I should not be surprised if we could put our hands upon the mountebank with very little trouble; but I feel sure he had nothing to do with the disappearance of the box."