close to it, there lay a wooden
platform which afforded standing room for six or seven men. Peter got
up on this platform and pulled a cord, which opened a concealed
sluice-gate and resulted in a roar of pouring water. Gradually the
platform lifted, and the king saw that it was placed on top of a tall
pine-tree that had been cut in the form of a screw, the gigantic
threads of which were well oiled. A whirling horizontal water-wheel,
through the centre of which the big screw came slowly upwards, with
Peter on the gradually elevating platform, formed the motive power of
the contrivance.

"You understand the mechanism?" said Armstrong. "By pulling one cord,
the water comes in on this side of the wheel and the platform ascends.
Another cord closes the sluice and everything is stationary. A third
cord opens the gate which lets the water drive the wheel in the
opposite direction and then the platform descends. You see, I have
taken away the old lower stairway that was originally built for the
tower, and this is the only means of getting up and down from the top
story. It does not, if you will notice, go entirely to the top, but
stops at that door, fifty feet from the rock, into which Peter is now
entering."

"It is a most ingenious invention," admitted the king. "I never saw
anything like it before."

"It would be very useful in a place like Stirling," said Johnny,
looking hard at his prisoner.

"I suppose it would," replied the king, in a tone indicating that it
was no affair of his, "but you see I'm not a Stirling man myself. I
belong rather to all Scotland; a man of the world, as you might say."

By this time Peter had climbed to the highest room of the tower,
worked his way on hands and knees out to the end of the beam, and had
drawn up to him the swaying body. With the deftness of expert
practice, he loosened the noose and the body dropped like a plummet
through the air, disappearing into the chasm below. Peter, taking the
noose with him, crawled backward, like a crab, out of sight, and into
the tower again. Armstrong, from below, had opened the other sluice,
and the empty platform descended as leisurely and as tremblingly as it
had risen. Armstrong himself cut the cords that bound the ankles of
his captives.

"Now, gentlemen," he said, "if you will step on the platform I shall
have the pleasure of showing you to your rooms."

Three armed men and the three prisoners moved upwards together.

"A fine sylvan view