“No, it doesn’t,” said Francis. “Well, a whale’s not a bird,” said Bernard. “And there are other things besides air and water,” said Francis. The Household Brigade was perhaps the handsomest. The Grand Salmoner led his silvery soldiers, and the 100th Halibuts were evidently the sort of troops to make the foes of anywhere “feel sorry they were born.” It was a glorious review, and when it was over the children found that they had been quite forgetting their desire to get home. But as the back of the last Halibut vanished behind the seaweed trees the desire came back with full force. Princess Maia had disappeared. Their own Princess was, they supposed, still performing her source-service. Suddenly everything seemed to have grown tiresome. “Oh, I do wish we could go home,” said Kathleen. “Couldn’t we just find the door and go out?” “We might _look_ for the door,” said Bernard cautiously, “but I don’t see how we could get up into the cave again.” “We can swim all right, you know,” Mavis reminded them. “I think it would be pretty low down to go without saying good-bye to the Princesses,” said Francis. “Still, there’s no harm in _looking_ for the door.” They did look for the door. And they did not find it. What they did find was a wall—a great gray wall built of solid stones—above it nothing could be seen but blue sky. “I do wonder what’s on the other side,” said Bernard; and someone, I will not say which, said: “Let’s climb up and see.” It was easy to climb up, for the big stones had rough edges and so did not fit very closely, and there was room for a toe here and a hand there. In a minute or two they were all up, but they could not see down on the other side because the wall was about eight feet thick. They walked toward the other edge, and still they could not see down; quite close to the edge, and still no seeing. “It isn’t sky at all,” said Bernard suddenly. “It’s a sort of dome—tin I shouldn’t wonder, painted to look like sky.” “It can’t be,” said someone. “It is though,” said Bernard. “There couldn’t be one so big,” said someone else. “But there _is_,” said Bernard. And then someone—I will not tell you who—put out a hand, and, quite forgetting the Princess’s warning, touched the sky. That hand felt something as faint and thin as a bubble—and instantly this something broke, and the sea came pouring into the Mer-people’s country. “Now you’ve done it,” said one of those whose hand it wasn’t. And there was no doubt about it; the person who owned the hand _had_ done it—and done it very thoroughly. It was plain enough now that what they had been living in was not water, and that this was. The first rush of it was terrible—but in less than a moment the whole kingdom was flooded, and then the water became clear and quiet.