it lay from the opening which led to Omean.

Then I had him draw a map of Omean, indicating plainly the position of
Shador and of the opening in the dome which led to the outer world.

These I studied until they were indelibly imprinted in my memory. From
Xodar I learned the duties and customs of the guards who patrolled
Shador. It seemed that during the hours set aside for sleep only one
man was on duty at a time. He paced a beat that passed around the
prison, at a distance of about a hundred feet from the building.

The pace of the sentries, Xodar said, was very slow, requiring nearly
ten minutes to make a single round. This meant that for practically
five minutes at a time each side of the prison was unguarded as the
sentry pursued his snail like pace upon the opposite side.

"This information you ask," said Xodar, "will be all very valuable
AFTER we get out, but nothing that you have asked has any bearing on
that first and most important consideration."

"We will get out all right," I replied, laughing. "Leave that to me."

"When shall we make the attempt?" he asked.

"The first night that finds a small craft moored near the shore of
Shador," I replied.

"But how will you know that any craft is moored near Shador? The
windows are far beyond our reach."

"Not so, friend Xodar; look!"

With a bound I sprang to the bars of the window opposite us, and took a
quick survey of the scene without.

Several small craft and two large battleships lay within a hundred
yards of Shador.

"To-night," I thought, and was just about to voice my decision to
Xodar, when, without warning, the door of our prison opened and a guard
stepped in.

If the fellow saw me there our chances of escape might quickly go
glimmering, for I knew that they would put me in irons if they had the
slightest conception of the wonderful agility which my earthly muscles
gave me upon Mars.

The man had entered and was standing facing the centre of the room, so
that his back was toward me. Five feet above me was the top of a
partition wall separating our cell from the next.

There was my only chance to escape detection. If the fellow turned, I
was lost; nor could I have dropped to the floor undetected, since he
was no nearly below me that I would have struck him had I done so.

"Where is the white man?" cried the guard of Xodar. "Issus commands
his presence." He started to turn to see if I were in another part of
the cell.

I scra