The four children had discussed this problem a good deal since they had left the island. It puzzled them very much indeed. How did it happen that George’s father knew a hiding-place that they didn’t know? Why, they had been over every inch of the island! It must be quite a big hiding-place too, if he had got all his stuff for his experiments with him. According to George’s mother, there had been quite a lot of this, to say nothing of stores of food.

“If Father knew a place I didn’t know, and never told me about it, I think he’s jolly mean,” George said half a dozen times. “I do really. It’s my island?”

“Well, he’ll probably tell you when he’s finished the work he’s on,” said Julian. “Then you’ll know. We can all go and explore it then, wherever it is.”

After they left the coastguard’s cottage they turned their steps home. They made their way along the cliff, and then saw the boy they had met before. He was standing on the path looking out to sea. The man was not with him.

He turned as they came up and gave them a pale kind of smile. “Hallo! Been up to see the coastguard?”

“Yes,” said Julian. “Nice old fellow, isn’t he?”

“I say,” said George, “I’m so sorry but my dog upset a tin of green paint, and the coastguard said it was yours. Can I pay you for it, please?”

“Goodness, no!” said the boy. “I don’t mind. There wasn’t much of it left anyway. That’s a nice dog of yours.”

“Yes, he is,” said George, warmly. “Best dog in the world. I’ve had him for years, but he’s still as young as ever. Do you like dogs?”

“Oh yes,” said the boy, but he made no move to pat Timmy or fuss him, as most people did. And Timmy did not run round the boy and sniff at him as he usually did when he met anyone new. He just stood by George, his tail neither up nor down.

“That’s an interesting little island,” said the boy, pointing to Kirrin. “I wish I could go there.”

“It’s my island,” said George, proudly. “My very own.”

“Really?” said the boy, politely. “Could you let me go over one day then?”

“Well — not just at present,” said George. “You see, my father’s there — working — he’s a scientist.”

“Really?” said the boy again. “Er — has he got some new experiment on hand, then?”

“Yes,” said George.

“Ah — and that queer tower is something to do with it, I suppose,” said the boy, looking interested for the first time. “When will his experiment be finished?”

“What’s that to do with you?” said Dick, suddenly. The others stared at him in surprise. Dick sounded rather rude, and it was not like him.

“Oh nothing!” said the boy, hastily. “I only thought that if his work will soon be finished, perhaps your brother would take me over to his island!”