Julian and George rowed strongly. They sent the boat along swiftly. George began to sing a rowing song and they all took it up. It was lovely to be on the sea in a boat again. Oh holidays, go slowly, don’t rush away too fast!

“George,” said her mother nervously, as they came near to Kirrin Island, “you will be careful of these awful rocks, won’t you? The water’s so clear today that I can see them all — and some of them are only just below the water.”

“Oh Mother! You know I’ve rowed hundreds of times to Kirrin Island!” laughed George. “I simply couldn’t go on a rock! I know them all, really I do. I could almost row blindfold to the island now.”

There was only one place to land on the island in safety. This was a little cove, a natural little harbour running up to a stretch of sand. It was sheltered by high rocks all round. George and Julian worked their way to the east side of the island, rounded a low wall of very sharp rocks, and there lay the cove, a smooth inlet of water running into the shore!

Anne had been looking at the island as the others rowed. There was the old ruined Kirrin Castle in the centre, just the same as ever. Its tumbledown towers were full of jackdaws as usual. Its old walls were gripped by ivy.

“It’s a lovely place!” said Anne, with a sigh. Then she gazed at the curious tower that now rose from the centre of the castle yard. It was not built of brick but some smooth, shiny material, that was fitted together in sections. Evidently the tower had been made in that way so that it might be brought to the island easily, and set up there quickly.

“Isn’t it queer?” said Dick. “Look at that little glass room at the top — like a look-out room! I wonder what it’s for?”

“Can anyone climb up inside the tower?” asked Dick, turning to Aunt Fanny.

“Oh yes. There is a narrow spiral staircase inside,” said his aunt. “That’s about all there is inside the tower itself. It’s the little room at the top that is important. It has got some extraordinary wiring there, essential to your uncle’s experiments. I don’t think he does anything with the tower — it just has to be there, doing something on its own, which has a certain effect on the experiments he is making.”

Anne couldn’t follow this. It sounded too complicated. “I should like to go up the tower,” she said.

“Well, perhaps your uncle will let you,” said her aunt.

“If he’s in a good temper,” said George.

“Now George — you’re not to say things like that,” said her mother.

The boat ran into the little harbour, and grounded softly. There was another boat there already — Uncle Quentin’s.

George leapt out with Julian and they pulled it up a little further, so that the others could get out without wetting their feet. Out they all got, and Timmy ran up the beach in delight.