"Andy, don't you think it would be a good thing to stay on this island and live here, instead of going back to our own island?" asked Mary. "We should be near to a good food-supply then!"
"No, I don't," said Andy, at once. "You forget we have left a signal on our island—and if any ship sees it and calls for us, we might be on this island, unable to be rescued because the tide was high and we couldn't get back."
"But couldn't we tie the signal up somewhere on this island?" said Tom.
"No," said Andy. "No ship could get to us here. This island is almost surrounded by a reef of the worst rocks I've ever seen. Look at them, right out there."
The children looked. Andy was right. A jagged line of rocks ran some way out from the coast. Between the rocks and the coast the sea lay trapped in a kind of big lagoon or lake, calm and smooth.
Tom frowned and looked puzzled. "Well, if no ship can get in to rescue us if we stay on this island," he said, "how in the wold did one get in to land all that food in the cave?"
Andy stared at Tom and looked as puzzled as Tom did. "Yes—that's odd," he said. "Well—maybe there is a way through at high tide. But we can't risk it. We must live on the first island, and when we want food we must come here and get it—and maybe we shall run into the folk who so strangely made a larder in trie Round Cave."
Mary stood up and tried to see what the next island was like. It looked much bigger than the first two. There was no line of rocks stretching to it, but only an unbroken spread of blue water. To get to the third island they would have to swim, or use a boat.
"Do you think we'd better leave a note in the cave to say that we are on the first island and would like to be rescued?" said Tom. "The people may come back at any time—and we could go away in their boat."
Andy shook his head. "I think we won't leave a note—or anything else to show we've been here," he said. "There's something a bit mysterious about all this, and if there's a secret going on, we'd better keep out of it till we know what it is."