“Because this floating island we are on,” said he, “is drifting southward all the time in a current. It’s an island that ordinarily belongs somewhere in the tropic zone—real sultry weather, sunstrokes and all that. If it doesn’t stop going southward pretty soon everything on it is going to perish.” “Well,” said the porpoises, “then the thing to do is to get it back into a warmer climate, isn’t it?” “Yes, but how?” said the Doctor. “We can’t _row_ it back.” “No,” said they, “but whales could push it—if you only got enough of them.” “What a splendid idea!—Whales, the very thing!” said the Doctor. “Do you think you could get me some?” “Why, certainly,” said the porpoises, “we passed one herd of them out there, sporting about among the icebergs. We’ll ask them to come over. And if they aren’t enough, we’ll try and hunt up some more. Better have plenty.” “Thank you,” said the Doctor. “You are very kind—By the way, do you happen to know how this island came to be a floating island? At least half of it, I notice, is made of stone. It is very odd that it floats at all, isn’t it?” “It is unusual,” they said. “But the explanation is quite simple. It used to be a mountainous part of South America—an overhanging part—sort of an awkward corner, you might say. Way back in the glacial days, thousands of years ago, it broke off from the mainland; and by some curious accident the inside of it, which is hollow, got filled with air as it fell into the ocean. You can only see less than half of the island: the bigger half is under water. And in the middle of it, underneath, is a huge rock air-chamber, running right up inside the mountains. And that’s what keeps it floating.” “What a pecurious phenometer!” said Bumpo. “It is indeed,” said the Doctor. “I must make a note of that.” And out came the everlasting note-book. The porpoises went bounding off towards the icebergs. And not long after, we saw the sea heaving and frothing as a big herd of whales came towards us at full speed. They certainly were enormous creatures; and there must have been a good two hundred of them. “Here they are,” said the porpoises, poking their heads out of the water. “Good!” said the Doctor. “Now just explain to them, will you please? that this is a very serious matter for all the living creatures in this land. And ask them if they will be so good as to go down to the far end of the island, put their noses against it and push it back near the coast of Southern Brazil.” The porpoises evidently succeeded in persuading the whales to do as the Doctor asked; for presently we saw them thrashing through the seas, going off towards the south end of the island. Then we lay down upon the beach and waited. After about an hour the Doctor got up and threw a stick into the water. For a while this floated motionless. But soon we saw it begin to move gently down the coast. “Ah!” said the Doctor, “see that?—The island is going North at last. Thank goodness!”