hem from reaching the
plain they would themselves be imprisoned by the wall. So they had to
leave some place to get around the wall, and, if the wall was visible,
all strangers or enemies would find the place to go around it and then
the wall would be useless. So the Flatheads cunningly made their wall
invisible, believing that everyone who saw the entrance to the mountain
would walk straight toward it, as we did, and find it impossible to go
any farther. I suppose the wall is really high and thick, and can't be
broken through, so those who find it in their way are obliged to go
away again."

"Well," said Dorothy, "if there's a way around the wall, where is it?"

"We must find it," returned Ozma, and began feeling her way along the
wall. Dorothy followed and began to get discouraged when Ozma had
walked nearly a quarter of a mile away from the entrance. But now the
invisible wall curved in toward the side of the mountain and suddenly
ended, leaving just space enough between the wall and the mountain for
an ordinary person to pass through.

The girls went in, single file, and Ozma explained that they were now
behind the barrier and could go back to the entrance. They met no
further obstructions.

"Most people, Ozma, wouldn't have figured this thing out the way you
did," remarked Dorothy. "If I'd been alone the invisible wall surely
would have stumped me."

Reaching the entrance they began to mount the stone stairs. They went
up ten stairs and then down five stairs, following a passage cut from
the rock. The stairs were just wide enough for the two girls to walk
abreast, arm in arm. At the bottom of the five stairs the passage
turned to the right, and they ascended ten more stairs, only to find at
the top of the flight five stairs leading straight down again. Again
the passage turned abruptly, this time to the left, and ten more stairs
led upward.

The passage was now quite dark, for they were in the heart of the
mountain and all daylight had been shut out by the turns of the
passage. However, Ozma drew her silver wand from her bosom and the
great jewel at its end gave out a lustrous, green-tinted light which
lighted the place well enough for them to see their way plainly.

Ten steps up, five steps down, and a turn, this way or that. That was
the program, and Dorothy figured that they were only gaining five
stairs upward each trip that they made.

"Those Flatheads must be funny people," she said to Ozma. "They d