When they returned to Double Eagle, they immediately announced their plans to Eliot and Drew, who were speechless at first, and then began to argue against making such a long and dangerous trip. Their mother had told them to stay put, they said, and she probably would accept Mrs. Williams’s invitation and would be looking forward to seeing them soon. Didn’t they owe it to her to obey her wishes? Annoyed by their timidity, Nathaniel told them they were free to stay in North Haven with all the other piazza-chair loafers, if that’s what they wanted. He and Will were capable of sailing the schooner by themselves, though it would be bully to have two extra hands to share watches.

“Jiminy, Nat, can’t we have a little time to think about it?”

“Yeah. A little is all.”

He and Will broke out the charts. The charts! There was a thrilling tension in them, a kind of tug-o’-war between science and poetry, exactitude and romance. The strange names of ports and shoals, headlands and capes stirred the mariner’s dreams, luring him to come and see, while the lines of latitude and longitude, the Compass Rose, the soundings whose numbers cluttered the blue of inshore waters, cautioned him to pay attention to stern realities like depth and bearing, lest his dreams lead him into trouble. As Will, with dividers and parallel rules, began to plot a course, Nathaniel traced with his eyes the capricious meanderings of the coastline, his imagination roving over seas stormy and calm to Nantucket, to the Chesapeake, the Outer Banks, the Georgia sea islands, and down the long linear plunge of the Florida peninsula to the Keys, their broken arc westering to their end at the Dry Tortugas. How that name sang to him. Even on paper, the Tortugas looked lonesome—a few punctuation marks clumped in the white reaches of the Gulf of Mexico. And somewhere off those desolate islands lay the ship whose salvaging had been his father’s biggest failure, possibly his only one, though there had been a lot of people who considered it anything but a failure.…

He took the sextant out of the drawer under the chart table, opened the case, and again read the engraved plate: IN GRATITUDE, ANNISQUAM. DRY TORTUGAS, FLORIDA, MARCH 10, 1879. Will looked up from his work and, with a gesture, asked Nathaniel what was in the case.

“A Plath,” he said, removing the instrument.

“See it?”

Handling the sextant as if it were a precious jewel, Will pointed it at the skylight and moved the indicator on the arc back and forth and declared it a beauty. The Germans were said to be a very precise people. Passing the Plath back to Nathaniel, he noticed the inscription and asked who was grateful to whom for what.