The displacing of the stone had left traces of the work.
But having seen their danger, they were prepared to provide against it.
Quick as thought they swept up the dirt, mortar, and rubbish, and threw it into the hole.
Then, joining hands, they raised the stone and lifted it into its place.
At that moment the key turned in the ma.s.sive and half rusty lock.
Sebastian entered the cell, tray in hand.
He had not the faintest suspicion that any thing was wrong.
"Will you leave the tray, Sebastian?"
"Why?"
"For us to work up our appet.i.tes; we have none to speak of now."
"Very good," returned the man; "there can be no harm in that."
"Of course not."
Sebastian then left the room.
"Thank goodness he"s gone!" said young Jack, who was all impatience to see what Harry was to do next.
Harry Girdwood watched until the door was fairly closed, and then turned again to the hole in the wall.
"Come along. Follow me, Jack."
"Trot on," said young Harkaway. "I"m after you."
They both scrambled through the hole, and when they were upon the other side, they replaced the stone.
And this done, the cell wore its original aspect.
Their way now lay down a rugged flight of steps, roughly cut in the solid earth.
The greatest care was necessary to avoid stumbling.
At length Harry Girdwood came to a standstill.
"Jack," he said, in a whisper,
"Here."
"Keep close now."
"Right."
"Nearer. Lend me a hand here. That"s it. Now help me to raise the stone here."
"Are you sure you are right?"
"Certain."
"Why?"
"This is exactly the position of the stone we have to lift away that old Dougherty describes in his plan."
Young Jack said no more, but lent his aid, and together they shifted the stone from its place.
Then daylight peeped into their dark hiding-place.
There was something leaning against the opening.
They pushed it aside, and stepping over a pile of sacks, found themselves in a covered shed overlooking the sea.
A place of curious aspect, with no sign of life in it
All was as still and gloomy-looking as if it were a huge mausoleum.
"I know what this place is," said Harry Girdwood.
"What?"
"It must be the dead-house on the terrace that I see noted down in old Dougherty"s plans."
While they were in the dead-house upon the terrace, a stirring scene was being enacted in the cell in the tower above, which they had only lately vacated.
In fact, Jack Harkaway the elder had only just entered the cell with Sebastian as they found themselves upon the terrace.
"Where are we now?"
There were several ugly-looking long boxes, whose shape was uniform and suggestive, standing upon tressels.
Besides these, there were no objects in the room or shed beyond a few badly-filled sacks which rested against the wall.
They looked anxiously about them.
Nearly facing the place where they had made their entrance was a door, and this they tried without a moment"s loss of time.
Fast.
Immovable.