He laughed roughly at his horrible joke, which was certainly calculated to affect the nerves of the intruder who was meant to hear it. Malipieri began to wonder when the man would give a sign of life.

"We can fill the well by plugging the arch in the outer chamber," he suggested. "Then the water will pour down the shaft and wash the body away."

"Yes, sir," assented Masin. "That is a good idea. Shall I go down and kill him now, sir?"

"Not yet," Malipieri answered, knocking the ash from his cigar. "We have not finished smoking, and there is no hurry. Besides, it occurs to me that if we drive anything into the hole when the water runs out, we shall not be able to get the plug away afterwards. Then we ourselves could never get here again."

A long silence followed. From time to time Masin made a little noise with the drill.

"Perhaps the fellow is asleep," he observed pleasantly at last. "So much the better, he will wake in Paradise!"

"It is of no use to run any risks," said Malipieri. "If we go down to kill him he may kill one of us first, especially if he has a revolver.

There is no hurry, I tell you. Do you happen to know how long it takes to starve a man to death?"

"Without water, a man cannot live a week, sir. That is the best idea you have had yet."

"Yes. We will wall him up in the vault. That is easy enough. Those boards that are over the shaft will do to make a little frame, and the stones are all here, just as we got them out. We can fasten up the frame with ends of rope."

"We have no mortar, sir."

"Mud will do as well for such a small job," answered Malipieri. "We can easily make enough. Give me your iron, in case he tries to get out, and go and get the boards and the rope."

Masin began to rise.

"In a week we can come and take him out," he remarked in a matter-of- fact way. "By that time he will be dead, and we can have his grave ready."

He laughed again, as he thought of the sensations his cheerful talk must produce in the mind of the man below.

"Yes," said Malipieri. "We may as well do it at once and go to bed. It is of no use to sit up all night talking about the fellow's body. Go and get the rope and the boards."

Masin was now on his feet and his heavy shoes made a grinding noise on the stones. At that moment a sound was heard from below, and Malipieri held up a finger and listened. Somebody was moving in the vault.

"You had better stay where you are," said Malipieri, speaking down.

"If you show yourself I will drop a stone on your head."

A hollow voice answered him from the depths.

"Are you Christians," it asked, "to wall a man up alive?"

"That is what we are going to do," Malipieri answered coolly. "Have you anything to say? It will not take us long to do the job, so you had better speak at once. How did you get in?"

"If I am to die without getting out, why should I tell you?" enquired the voice.

Malipieri looked at Masin.

"There is a certain sense in what the man says, sir," Masin said thoughtfully.

"My good man," said Malipieri, speaking down, "we do not want anybody to know the way to this place for a few days, and as you evidently know it better than we do, we intend to keep you quiet."

"If you will let me out, I can serve you," answered the man below.

"There is nobody in Rome who can serve you as I can."

"Who are you?" asked Malipieri.

"Are you going to let me out, Signor Malipieri?" enquired the man. "If you are, I will tell you."

"Oh, you know my name, do you?"

"Perfectly. You are the engineer engaged by the Senator Volterra to find the treasure."

"Yes. Quite right. What of that?"

"You have found it," answered the other. "Of what use will it be to kill me? I cannot take that statue away in my waistcoat pocket, if you let me out, can I?"

"You had better not make too many jokes, my man, or we will put the boards over this hole in five minutes. If you can really be of use to me, I will let you out. What is your name?"

"Toto," answered the voice sullenly.

"Yes. That means Theodore, I suppose. Now make haste, for I am tired of waiting. What are you, and how did you get in?"

"I was the mason of the palace, until the devil flew away with the people who lived in it. I know all the secrets of the house. I can be very useful to you."

"That changes matters, my friend. I have no doubt you can be useful if you like, though we have managed to find one of the secrets without you. It happens to be the only one we wanted to know."

"No," answered Toto. "There are two others. You do not know how I got in, and you do not know how to manage the 'lost water.'"

"That is true," said Malipieri. "But if I let you out you may do me harm, by talking before it is time. The government is not to know of this discovery until I am ready."

"The government!" exclaimed Toto contemptuously, from his hiding- place. "May an apoplexy seize it! Do you take me for a spy? I am a Christian."

"I begin to think he is, sir," put in Masin, knocking the ash from his pipe.

"I think so, too," said Malipieri. "Throw away that iron, Masin. He shall show himself, at all events, and if we like his face we can talk to him here."

Masin dropped the drill with a clang. Toto's hairy hand appeared, grasping the golden wrist of the statue, as he raised himself to approach the hole.

"He is a mason, as he says," said Masin, catching sight of the rough fingers.

"Did you take me for a coachman?" enquired Toto, thrusting his shaggy head forward cautiously, and looking up through the aperture.

"Before you come up here," Malipieri answered, "tell me how you got in."

"You seem to know so much about the overflow shaft that I should think you might have guessed. If you do not believe that I came that way, look at my clothes!"

He now crawled upon the body of the statue, and Malipieri saw that he was covered with half-dried mud and ooze.

"You got through some old drain, I suppose, and found your way up."