At this Gerstein was working, thoughtfully scanning it at times and then making additions to it. Dave believed that it had something to do with the treasure.
"Our treasure," he reflected, "and I'll play something else than the spy if I get a chance to look over that chart, whatever it is."
He watched the man's movements for over half an hour. Then Gerstein folded up the paper, placing it in a thin tin tobacco box. This he secured in a pocket in the blue shirt he wore, buttoning the pocket flap securely.
Dave got no further sight of the mysterious paper, if such it was, during the next week. He felt himself justified in trying to get a chance to secure the little tin box. Twice he visited Gerstein's cabin secretly, while its occupant was on deck. Gerstein, however, apparently carried the box with him wherever he went.
One night, when he slept, Dave crept into the cabin, the door of which for a wonder had been left unlocked. He ransacked Gerstein's clothing, but with no result.
"Got it somewhere in bed with him," thought Dave. "I don't dare to try and find it, though. I would surely wake him up. I believe I will tell Captain Broadbeam about the little tin box. If it in any way concerns this treasure, why haven't we the right to take it away from Gerstein, even by force?"
Before Dave had an opportunity to consult with Captain Broadbeam, however, something transpired that changed all his plans.
It was a dark and stormy night. The weather had been rough all day. Dave came on deck about eight o'clock to find the captain on duty. A few men were making things tidy about the stern deck.
The Swallow was plowing the water, slanted like a swordfish in action. Dave held to a handle at the side of the cabin, peering into the darkness that hung about them like a pall.
According to the calculations of the captain they were somewhere in the vicinity of the Windjammers' Island--probably within fifty miles of it, he had told Amos Fearless at sunset.