While he was thus overcome by the difficulties of his position, and as
he had about concluded that he had undertaken an impossibility, he was
startled by the deep tones of the great bell that hung in the archway
of the gate, striking the hour of ten o'clock. Directly afterwards
came the measured tramp of the guard and the clank of their weapons as
they made their round for the purpose of relieving the sentinels on
duty, and replacing them with fresh men. Réné sat so near the gate-way
that he could overhear what was said when that post was relieved, and
distinguishing above the rest the voice of his old friend Simon, the
armorer, he became convinced that he had been placed on duty at this
most important point.

After relieving this post the guard resumed their march, and passed so
close to where Réné sat in the shadow of the great gun that, had the
night been a shade lighter, they must have seen him. As it was, he
escaped detection, and once more breathed freely as their footsteps
sounded fainter and fainter in the distance. After a while he heard
them return along the opposite side of the fort, and finally halt in
front of the guard-house, when silence again reigned throughout the
entire enclosure.

As Réné still sat on the gun-carriage, thinking how he might turn to
account the fact of his friend Simon being on duty at the main gateway,
the sound of a groan came from that direction. As it was repeated, the
lad sprang to his feet and walked quietly but rapidly towards the place
whence it came. When near the gateway he laid down his cross-bow and
advanced without it, until brought to a halt by a sharp challenge in
the gruff voice of old Simon.