He racked his brains for an explanation of the mystery, and when he reached the door of the palace, after eleven o’clock, he had come to the conclusion that in spite of appearances there must be some entrance to the vaults of which he knew nothing, and it was all-important to find it.  He regretted the quixotic impulse which had restrained him from exploring everything at once.  It would have been far better to go to the end of his discovery, and he wondered why he had not done go.  He would not have insulted himself by supposing that Sabina could believe him capable of taking the gem from the ring of the statue, in other words, of stealing, since whoever the rightful owner might be, nothing in the vault could possibly belong to him, and he regarded it all as her property, though he doubted whether he could ever obtain for her a tenth part of the value it represented.  He had acted on an impulse, which was strengthened until it looked plausible by the thought of the intense pleasure he would take in showing her the wonderful discovery, and in leading her safely through the mysterious intricacies of the strange place.  It had been a very selfish impulse after all, and if he really let her come the next day, there might even be a little danger to her.

He let himself in and locked the postern door behind him.  The porter and his wife were asleep and the glass window of the lodge door was quite dark.  Malipieri lighted a wax taper and went upstairs.

Masin was waiting, and opened when he heard his master’s footsteps on the landing.  As a rule, he went to bed, if Malipieri went out in the evening; both men were usually tired out by their day’s work.

“What is the matter?” Malipieri asked.

“There is somebody in the vaults,” Masin answered.  “I had left my pipe on a stone close to the padlocked door and when you were gone I took a lantern and went down to get it.  When I came near the door I was sure I heard some one trying it gently from the other side.  I stopped to listen and I distinctly heard footsteps going away.  I ran forward and tried to find a crack, to see if there were a light, but the door is swollen with the dampness and fits tightly.  Besides, by the time I had reached it the person inside must have got well away.”

“What time was it?” asked Malipieri, slipping off his light overcoat.

“You went out at nine o’clock, sir.  It could not have been more than half an hour later.”

“Light both lanterns.  We must go down at once.  See that there is plenty of oil in them.”

In five minutes both men were ready.

“You had better take your revolver, sir,” suggested Masin.

Malipieri laughed.

“I have had that revolver since I was eighteen,” he said, “and I have never needed it yet.  Our tools are there, and they are better than firearms.”

They went down the staircase quietly, fearing to wake the porter, and kept close to the north wall till they reached the further end of the courtyard.  When they had passed the outer door at the head of the winding staircase, Malipieri told Masin to lock it after them.