ybe it
will be different down there."

They did not face famine that summer as they had the first summer. The
diet of meat and dried herbs was rough and plain but there was enough of
it.

Full summer came and the land was again burned and lifeless. There was
nothing to do but sit wearily in the shade and endure the heat, drawing
what psychological comfort they could from the fact that summer solstice
was past and the suns were creeping south again even though it would be
many weeks before there was any lessening of the heat.

It was then, and by accident, that Lake discovered there was something
wrong about the southward movement of the suns.

He was returning from the lookout that day and he realized it was
exactly a year since he and the others had walked back to the caves
while Bemmon swung on the limb behind them.

It was even the same time of day; the blue sun rising in the east behind
him and the yellow sun bright in his face as it touched the western
horizon before him. He remembered how the yellow sun had been like the
front sight of a rifle, set in the deepest V notch of the western
hills--

But now, exactly a year later, it was not in the V notch. It was on the
north side of the notch.

He looked to the east, at the blue sun. It seemed to him that it, too,
was farther north than it had been although with it he had no landmark
to check by.

But there was no doubt about the yellow sun: it was going south, as it
should at that time of year, but it was lagging behind schedule. The
only explanation Lake could think of was one that would mean still
another threat to their survival; perhaps greater than all the others
combined.

The yellow sun dropped completely behind the north slope of the V notch
and he went on to the caves. He found Craig and Anders, the only two who
might know anything about Ragnarok's axial tilts, and told them what he
had seen.

"I made the calendar from the data John gave me," Anders said. "The
Dunbar men made observations and computed the length of Ragnarok's
year--I don't think they would have made any mistakes."

"If they didn't," Lake said, "we're in for something."

Craig was watching him, closely, thoughtfully. "Like the Ice Ages of
Earth?" he asked.

Lake nodded and Anders said, "I don't understand."

"Each year the north pole tilts toward the sun to give us summer and
away from it to give us winter," Lake said. "Which, of course, you
know. But there can be still an