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Phi did not sit long on the ice-pile under the snow-fog. He was born for action. Something must be done. Quickly he was on the run.
As he rushed back over the way in which he had come, something caught his eye.
An immense ice-pan had been up-ended by the press of the drift. It had toppled half over and lodged across the edge of a smaller cake. Now, like an ancient drawbridge, it hung suspended over the black moat of the salt water channel.
The boy's quick eye had detected a very slight movement downward. As he remembered it now, the cake had made 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?"