But the altimeter needle dropped obediently. Twelve hundred feet, a thousand. Irene eased the stick back again and leveled the airplane. Her hands were clammy and slipped a bit on the rubber grip. Ahead of her was nothing, just the same black moon-speckled landscape, not the slightest interruption. She glanced at the altimeter (nine hundred and eighty feet) and the speed gauge (ninety miles an hour). Then the clock, which showed that four minutes had passed, that if their calculations were perfect, Baker Island should be thrusting up from the ocean any second now.

Forty-five minutes.

Fifty minutes.

Irene glanced over her shoulder at Sam. It was dark inside the cabin, lit only by the moonlight and the bulb attached to the navigator’s table, and in that glimpse she couldn’t tell if his expression, as he stared out the small, ovoid window, was grim or just flat.

She scribbled, See anything?

He replied, Box compass.

Of course they had discussed what to do if navigation failed, if a certain mass of land did not turn up when and where it was supposed to. There was no need to panic, at least not right away. On an ocean so vast as the Pacific, using navigation methods that relied on natural variables and imperfect human observations, errors would occur. You simply tried to keep the margin of that error within reasonable—that is to say, survivable—bounds.

So Baker Island had not turned up exactly where it was supposed to. It must still exist somewhere in the vicinity. According to the laws of geometry, from a point one thousand feet above the earth’s surface, the human eye could find the horizon across thirty-nine miles of open ocean in each direction; if you flew your airplane in four straight lines of forty miles each to form a square—boxing the compass, as they call it—you stood the best chance of detecting your objective before you ran out of fuel. At night, of course, your visibility wasn’t so exact. If the moon was bright and the weather was clear, as it was now, you might still have a hard time detecting some imperfection upon the ocean’s surface that might or might not represent an island. Still, you had to try. Sam and Irene had practiced this very maneuver atop the California desert over and over, by night and by day, and while Sam had always flown the airplane as Irene worked the navigation, still she’d passed him the necessary commands, she’d figured out which direction and for how long they should make their passes over the sand. Why, she’d had the tougher job! She knew what to do. She had just about expected this message from Sam, scribbled in block letters on a piece of square white notepaper.

She banked the airplane and began the first side of the square.