“We cannot padlock the other door from the inside,” he explained, “for there are no hasps.  If the man managed to pass us he might get out this way.”

He led the way down, making as little noise as possible.  Masin held up his lantern, peering into the gloom over Malipieri’s shoulder.

“No one could pass the other door without breaking it down,” Malipieri said.

They reached the floor of the cellars, which extended in both directions from the foot of the staircase, far to the left by low, dark vaults like railway tunnels, and a short distance to the right, where they ended at the north-west corner.  The two men turned that way, but after walking a dozen yards, they turned to the left and entered a damp passage barely wide enough for them both abreast.  It ended at the padlocked door, and before unlocking the latter Malipieri laid his ear to the rough panel and listened attentively.  Not a sound broke the stillness.  He turned the key, and took off the padlock and slipped it into his pocket before going on.  Without it the door could not be fastened.

The passage widened suddenly beyond, in another short tunnel ending at the outer foundation wall of the palace.  In this tunnel, on the right-hand side, was the breach the two men had first made in order to gain access to the unexplored region.  Now that there was an aperture, the running water on the other side could be heard very distinctly, like a little brook in a rocky channel, but more steady.  Both men examined the damp floor carefully with their lanterns, in the hope of finding some trace of footsteps; but the surface was hard and almost black, and where there had been a little slime their own feet had rubbed it off, as they came and went during many days.  The stones and rubbish they had taken from the wall had been piled up and hardened to form an inclined causeway by which to reach the irregular hole.  This was now just big enough to allow a man to walk through it, bending almost double.  Masin lighted one of the lamps, which they generally left at that place, and set it on a stone.

Malipieri began to go up, his stick in his right hand, the lantern in his left.

“Let me go first, sir,” said Masin, trying to pass him.

“Nonsense!” Malipieri answered sharply, and went on.

Masin kept as close to him as possible.  He had picked up the lightest of the drilling irons for a weapon.  It must have weighed at least ten pounds and it was a yard long.  In such a hand as Masin’s a blow from it would have broken a man’s bones like pipe stems.

The wall was about eight feet thick, and when Malipieri got to the other end of the hole he stopped and looked down, holding out his lantern at arm’s length.  He could see nothing unusual, and he heard no sound, except the gurgle of the little black stream that ran ten feet below him.  He began to descend.  The masonry was very irregular, and sloped outwards towards the ground, so that some of the irregularities