"The question of what has become of this great sea which once washed the shore we are now leaving," said Professor Henderson, seriously, "is a remarkably interesting one. The ocean may have merely receded for a few miles at the time of the volcanic eruption and earthquake which threw off this new planet."
Phineas Roebach shook his head at this, but said nothing.
"It may be," pursued Mr. Henderson, "that that part of our old world that was shot into space did not include much of this Arctic sea. We may find beyond here," pointing, as he spoke, ahead, "instead of the receded ocean, no ocean at all. We cannot believe that this island in the air is spherical like our own old earth. It is a ragged form which will show on what we may call the under side the very convolutions and scars made by its breaking away from the old earth. Do you get my meaning?"
"Yo' suttenly is a most liquid speaker, Perfesser," declared Washington White. "Yo' was sayin' dat w'en disher new planet broke off de earf, she slopped over de whole Arctic Ocean."
"Perhaps that puts it quite as simply," said Professor Henderson, smiling grimly. "The ocean 'slopped over'. It was either left behind to partly fill the cavity left by the departure of this torn-away world we are living on, or it has receded into the valleys and sinks upon the other side of this small planet."
Phineas Roebach threw up both hands and groaned.
"It's as clear as mud!" he cried. "I don't understand a thing about it."
But the old professor went on without heeding him, knowing that his pupils, Jack and Mark, were deeply interested in the mystery of this torn-away world, or island in the air.
"It is a moot question whether or not the weight of the water which lay in this vast sink, before the eruption, was not needed, and is not needed right now, for the balancing of this tiny planet we are living on. Nature adjusts herself to every change more quickly than human intelligence. How much of the crust of the earth, extending up into the polar regions, was broken away from our old world, we do not know. But that it is now perfectly balanced we can have no doubt—that balance is proved by the fact of the regularity of the recurrence of night and day."
These and many other observations Professor Henderson spoke as the party continued its rugged advance over the more or less dry bottom of the ocean. In two hours the party was observed by the crew of the whaler at work on the carcass of the great whale. The sailors signaled to them, and when the boys and their friends drew near, some of the whalemen ran forward to welcome them.