Doctor Luke and Billy Topsail had encountered nothing as doubtful. They paused on the brink. A long, thin line of solid pan-ice, ghostly white in the dusk beyond, was attached to the rocks of the Little Spotted Horse. It led all the way to Tickle-my-Ribs. They must make that line of solid ice. They must cross the wide lane of black, delicately frozen new ice that lay between and barred their way. And there was no way out of it.
Doctor Luke waited for the moon. When the light broke—a thin, transient gleam—he started.
"Wait," said he, "until I'm across."
A few fathoms forth the ice began to yield. A moment later Doctor Luke stopped short and recoiled. There was a hole—gaping wide and almost under his feet. He stopped. The water overflowed and the ice cracked. He must not stand still. To avoid a second hole he twisted violently to the right and almost plunged into a third opening. It seemed the ice was rotten from shore to shore.
And it was a long way across. Doctor Luke danced a zigzag towards the pan-ice under the cliffs—spurting forward and retreating and swerving. He did not pause. Had he paused he would have dropped through. When he was within two fathoms of the pan-ice a foot broke through and tripped him flat on his face. With his weight thus distributed he was momentarily held up. Water squirted and gurgled out of the break—an inch of water, forming a pool.
Doctor Luke lay still and expectant in this pool.