"Why would we be half-bound?" said Bruno.

"We're not prisoners!"

But the Professor had forgotten all about them by this time, and was speaking to the Warden again. "You'll be glad to hear," he was saying, "that the Barometer's beginning to move----"

"Well, which way?" said the Warden----adding, to the children, "Not that I care, you know. Only he thinks it affects the weather. He's a wonderfully clever man, you know. Sometimes he says things that only the Other Professor can understand. Sometimes he says things that nobody can understand! Which way is it, Professor? Up or down?"

"Neither!" said the Professor, gently clapping his hands. "It's going sideways----if I may so express myself."

"And what kind of weather does that produce?" said the Warden. "Listen, children! Now you'll hear something worth knowing!"

"Horizontal weather," said the Professor, and made straight for the door, very nearly trampling on Bruno, who had only just time to get out of his way.

"Isn't he learned?" the Warden said, looking after him with admiring eyes. "Positively he runs over with learning!"

"But he needn't run over me!" said Bruno.

The Professor was back in a moment: he had changed his dressing-gown for a frock-coat, and had put on a pair of very strange-looking boots, the tops of which were open umbrellas. "I thought you'd like to see them," he said. "These are the boots for horizontal weather!"

"But what's the use of wearing umbrellas round one's knees?"

"In ordinary rain," the Professor admitted, "they would not be of much use. But if ever it rained horizontally, you know, they would be invaluable----simply invaluable!"

"Take the Professor to the breakfast-saloon, children," said the Warden. "And tell them not to wait for me. I had breakfast early, as I've some business to attend to." The children seized the Professor's hands, as familiarly as if they had known him for years, and hurried him away. I followed respectfully behind.