"What's wrong?" asked Trendon, frowning.
"He came up on deck, wild-eyed and staggering. There was a sheet of paper in his hand which seemed to have some bearing on his trouble. When he found you had gone to the island without him he began to rage like a maniac. I had to have him carried down by force. In the rumpus the paper disappeared. I assumed the responsibility of giving him an opiate."
"Quite right," approved Trendon. "I'll go down. Will you come with me, sir?" he said to the captain.
They found Slade in profound slumber.
"Won't do to wake him now," growled Trendon. "Hello, what's here?"
Lying in the hollow of the sick man's right hand, where it had been crushed to a ball, was a crumpled mass of tracing paper. Trendon smoothed it out, peered at it and passed it to the captain.
"It's a sketch of an Indian arrow-head," he exclaimed in surprise, at the first glance. "What are all these marks?"
"Map of the island," barked Trendon. "Look here."
The drawing was a fairly careful one, showing such geographical points as had been of concern to the two-year inhabitants. There was the large cavern, indicated as they had found it, and at a point between it and the headland the legend, "Seal Cave."
"But it's wrong," cried Captain Parkinson, setting finger to the spot. "We passed there twice. There's no opening."
"No guarantee that there may not have been," returned the other. "This island has been considerably
