“Stop jigging about like that,” said the Professor, crossly. “I don’t remember asking them. I would have told Jenny the maid, if I had.”

“You did tell her!” shouted Tinker, still jigging about, with Mischief the monkey jigging too in delight. “She’s already made up the beds. I helped her. She’s angry because you left your breakfast and now it’s almost dinner-time. She’s cleared it away.”

“Bless us all — so that’s why I feel so hungry and cross!” said Professor Hayling, and he began to laugh. He had a tremendous laugh, and the children couldn’t help laughing too. What an odd fellow — so brainy, such a fine scientist — with the most enormous amount of knowledge in his head — and yet no memory for such ordinary things as breakfast and visitors and telephone calls.

“It was just a misunderstanding, sir,” said Julian, politely. “It was very, very kind of you to invite us here when we can’t be at home because of the scarlet fever. We’ll try not to be a nuisance, and if there’s anything we can do to help you, please ask us. We’ll make as little noise as possible, and keep out of your way, of course.”

“You hear that, Tinker?” said Professor Hayling, suddenly swinging round on the startled Tinker. “Why can’t you do the same — make a very little noise, and keep out of my way? You know I’m very busy now — on a MOST IMPORTANT project.” He turned to Julian. “You’ll be very welcome if you keep Tinker out of my way. And NOBODY — absolutely NOBODY — is to go up into that tower. Understand?”

They all looked up to where he was pointing, and saw a tall, slender tower rising up amid the trees. It had curious tentacle-like rods sticking out at the top, and these shook slightly in the breeze.

“And don’t ask me questions about it,” went on the Professor, looking fiercely at George. “Your father’s the only other man who knows what it’s for, and he knows how to keep his mouth shut.”

“None of us would dream of prying, sir,” said Julian. “It’s very, very kind of you to offer to have us here, and do believe me when I say we shan’t be any trouble to you at all — but a help if you’ll allow us.”

“Ah well, you sound a sensible fellow, I must say,” said the Professor, who had now calmed down, and looked quite peaceable. “Well, I’ll say good-bye for now and go and have my breakfast. I hope it’s fried eggs and bacon. I’m very hungry.”

“Dad — Jenny’s cleared your breakfast AWAY! I told you that before!” said Tinker in despair. “It’s almost dinner-time, now.”

“Ah good — good!” said the Professor. “I’ll come at once.”

And he led the way indoors, followed by the five children, with Timmy and Mischief, all looking rather worried. Really, nobody ever knew what the Professor was going to do or say next!