"We can look," returned Billy; and presently they set off to explore the island. All at once Jack stooped and picked up a jam-tin.
"Hullo!" he said. "Here's a jam-tin—wonder who was the tripper? Fairly recent, too—the jam's still fresh in the bottom."
"Show me, comrade," said Patch, taking the tin and peering into it, his detective instincts aroused. He glanced round him. "It's a funny thing," he went on, "but I can smell something burning—the smell of smoke. Any of you notice it?"
"No," answered Billy slowly. "Where's it coming from, then? Surely not from shore."
"Unless the old Coll's on fire," suggested Jack with a grin.
"No—I thought ... I say, comrade, look at this—there's a giddy old cave here!"
"Where?" asked Jack, pushing forward.
"There—underneath that clump of bush. I can see the opening quite plainly, and if the smoke's not coming out of there I'll eat my hat."
Leaping up, the schoolboy detective pushed aside the screen of bushes, and the opening to a cave lay disclosed. Patch ducked his head and made as if to enter, but Jack's voice arrested him in the cave's mouth.
"Hold hard, Patchie!"