In the interior we found that not only the plants and trees were suffering from the cold:  the animal life was in even worse straits.  Everywhere shivering birds were to be seen, their feathers all fluffed out, gathering together for flight to summer lands.  And many lay dead upon the ground.  Going down to the shore, we watched land-crabs in large numbers taking to the sea to find some better home.  While away to the Southeast we could see many icebergs floating—­ a sign that we were now not far from the terrible region of the Antarctic.

As we were looking out to sea, we noticed our friends the porpoises jumping through the waves.  The Doctor hailed them and they came inshore.

He asked them how far we were from the South Polar Continent.

About a hundred miles, they told him.  And then they asked why he wanted to know.

“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.