"Why not,—the professor is down that hole," cried Harry, "we must do something to save him."
"You can do more by keeping cool-headed than any other way," rejoined Frank. "A crevasse, into one of which the professor has fallen, is not 'a hole' as you call it, but a long rift in the earth above which snow has drifted. Sometimes they are so covered up that persons can cross in safety, at other times the snow 'bridge' gives way under their weight and they are precipitated into the crevasse itself,—an ice-walled chasm."
"Then we may never get the professor out," cried Billy in dismay. "How deep is that crevasse likely to be?"
"Perhaps only ten or twenty feet. Perhaps several hundred," was the alarming reply.
CHAPTER XXV.
THE VIKING'S SHIP.
Suddenly, from the depths as it seemed, there came a faint cry.
It was the professor's voice feebly calling for aid. Frank hastened forward but dared not venture too near the edge of the hole through which the scientist had vanished.
"Are you hurt, professor?" he cried, eagerly, and hung on the answer.
"No," came back the reply, "not much, but I can't hold on much longer."