“We know many secrets in our trade, from father to son,” answered Toto gruffly.

“You must have lifted the boards, with the stones on them, to get out of the shaft.  Why did you put them back in their place?”

“You seem to think I am a fool!  I did not mean to let you know that I had been here, so I put them back, of course.  I supposed that I could get out through the cellars, but you have put a padlock on the inner door.”

“Is there any way of turning water into that shaft?”

“Only by filling the well, I think.  If the Tiber rises, the water will back up the shaft through the drain.  That is why the ancients who built the well made another way for the water to run off.  When the river is swollen in a flood it must be much higher in the shaft than the bottom of the well, and if the ‘lost water’ were running in all the time, the air would probably make it back, so that the shaft would be useless and the well would be soiled with the river water.”

“You evidently know your trade, Master Toto,” said Masin, with some admiration for his fellow-craftsman’s clear understanding.

“You know yours,” retorted Toto, who was seldom at a loss, “for just now you talked of killing like a professional assassin.”

This pleasing banter delighted Masin, who laughed heartily, and patted Toto on the back.

“We shall be good friends,” he said.

“In this world one never knows,” Toto answered philosophically.  “What are you going to do?”

“You must come back with as to my apartment,” said Malipieri, who had been considering the matter, “You must stay there a couple of days, without going out.  I will pay you for your time, and give you a handsome present, and plenty to eat and drink.  After that you will be free to go where you please and say what you like, for the secret will be out.”

“Thank you,” answered Toto without enthusiasm.  “Are you going to tell the government about the treasure?”

“The Senator will certainly inform the government, which has a right to buy it.”

To this Toto said nothing, but he lifted his legs out of the hole and stood up, ready to go.  Malipieri and Masin took up their lanterns.

CHAPTER XI

Masin led the way back, Toto followed and Malipieri went last, so that the mason was between his two captors.  They did not quite trust him, and Masin was careful not to walk too fast where the way was so familiar to him, while Malipieri was equally careful not to lag behind.  In this order they reached the mouth of the overflow shaft, covered with the loaded boards.  Masin bent down and examined them, for he wished to convince himself that the stones had been moved since he had himself placed them there.  A glance showed that this was the case, and he was about to go on, when he bent down again suddenly and listened, holding up his hand.