"Yes! but—let us hurry on!"
They advanced rapidly; Simpson's voice could be heard urging on the dogs; they ran along on a brilliant surface, all aglow with a phosphorescent light, and the runners of the sledge seemed to toss up a shower of sparks. The doctor ran on ahead to examine this snow, when suddenly, as he was trying to jump upon a hummock, he disappeared from sight. Bell, who was near him, ran at once towards the place.
"Well, Doctor," he cried anxiously, while Hatteras and Simpson joined him, "where are you?"
"Doctor!" shouted the captain.
"Down here, at the bottom of a hole," was the quiet answer. "Throw me a piece of rope, and I'll come up to the surface of the globe."
They threw a rope down to the doctor, who was at the bottom of a pit about ten feet deep; he fastened it about his waist, and his three companions drew him up with some difficulty.
"Are you hurt?" asked Hatteras.
"No, there's no harm done," answered the doctor, wiping the snow from his smiling face.
"But how did it happen?"
"O, it was in consequence of the refraction," he answered, laughing; "I thought I had about a foot to step over, and I fell into this deep hole! These optical illusions are the only ones left me, my friends, and it's hard to escape from them! Let that be a lesson to us all never to take a step forward without first testing the ice with a staff, for our senses cannot be depended on. Here our ears hear wrong, and our eyes deceive us! It's a curious country!"