“You see,” she said, “the inside of our wall is only about ten feet high, but it goes down on the other side for forty feet or more. It is built on a hill. Now, I don’t want you to feel obliged to come out and fight. You can stay inside and get the shields ready for us to take. We shall keep on rushing back for fresh weapons. Of course the tunnel’s much too narrow for the Under Folk to get in, but they have their regiment of highly trained Sea Serpents, who, of course, can make themselves thin and worm through anything.” “Cathay doesn’t like serpents,” said Mavis anxiously. “You needn’t be afraid,” said the Princess. “They’re dreadful cowards. They know the passage is guarded by our Lobsters. They won’t come within a mile of the entrance. But the main body of the enemy will have to pass quite close. There’s a great sea mountain, and the only way to our North Tower is in the narrow ravine between that mountain and Merland.” The tunnel ended in a large rocky hall with the armory, hung with ten thousand gleaming shields, on the one side, and the guardroom crowded with enthusiastic Lobsters on the other. The entrance from the sea was a short, narrow passage, in which stood two Lobsters in their beautiful dark coats of mail. Since the moment when the blue sky that looked first so like sky and then so like painted tin had, touched, confessed itself to be a bubble—confessed, too, in the most practical way, by bursting and letting the water into Merland—the children had been carried along by the breathless rush of preparations for the invasion, and the world they were now in had rapidly increased in reality, while their own world, in which till today they had always lived, had been losing reality at exactly the same rate as that by which the new world gained it. So it was that when the Princess said: “You needn’t go out and attack the enemy unless you like,” they all answered, in some astonishment: “But we _want_ to.” “That’s all right,” said the Princess. “I only wanted to see if they were in working order.” “If what were?” “Your coats. They’re coats of valor, of course.” “I think I could be brave without a coat,” said Bernard, and began to undo his pearl buttons. “Of course you could,” said the Princess. “In fact, you must be brave to begin with, or the coat couldn’t work. It would be no good to a coward. It just keeps your natural valor warm and your wits cool.” “It makes you braver,” said Kathleen suddenly. “At least I hope it’s me—but I expect it’s the coat. Anyhow, I’m glad it does. Because I do want to be brave. Oh, Princess!” “Well?” said the Princess, gravely, but not unkindly, “what is it?” Kathleen stood a moment, her hands twisting in each other and her eyes downcast. Then in an instant she had unbuttoned and pulled off her coat of pearly mail and thrown it at the Princess’s feet. “I’ll do it without the coat,” she said, and drew a long breath.