a far more obtuse angle with
the surface of the pool a half-hour before than it did now.

Was there hope in this? Hastily he arranged three bits of ice in one
pile, then two in another. By dropping on his stomach and squinting
across these, he could just see the tip of the up-ended cake. If it
were in motion the tip would soon disappear. Eagerly he strained his
eyes for a few seconds. Then, in disgust, he closed his eyes. The
cake did not seem to move.

For some time he lay there in deep thought. He was searching in his
mind for a way out.

After a while he opened his eyes. More from curiosity than hope, he
squinted once more along the line. Then, with a wild shout, he sprang
into the air. The natural drawbridge was falling. Its point had
dropped out of line.

The shout died on his lips. His eyes had warned him that the channel
of water was widening. If it widened too rapidly, if the drawbridge
fell too slowly, or ceased to fall at all, hope would die.

Moment by moment he measured the two distances with his eye. Rover,
sitting by his side, now and again peered up into his eyes as if to
say: "What's it all about?"

Now the drawbridge took a sudden drop of a foot. Hope rose. Then,
again, it appeared wedged solidly in place. It did not move. The
channel widened a foot, two feet, three. Hope seemed vain.

But now came a sudden tide tremor across the floe. With a crunching
sound the massive cake toppled and fell.

The boy was on his feet in an instant. The chasm was bridged. But the
cake had broken in two. Could he make it?

Calling to his dog, he leaped upon the slippery surface. An
ever-widening river of water flowed where the cake had split. With one
wild bound, he cleared it. The dog followed. In another moment they
were safe on the other side.

"That's well over with," the boy sighed, patting the old dog on the
head. "Now the question is, how can we find our friends?"

That, indeed, was a problem. They had covered considerable ground.
The ice had been shifting. To pick up their back trail seemed
impossible. An hour's search convinced him that it could not be done.
He sat down in a brown study. He could not go away and leave these
girls to drift north and perish, yet further search seemed futile.

Just as he was about to despair, Rover began to bark in the distance.
Following the sound, he came to where the dog was apparently barking at
nothing. But as the boy approached,