Bell watched him sternly. When he spoke, the chief investigator’s voice was glacial: “I’ll tell you what happened. You nod. Understand?”

Eustace was trembling.

“Understand?” Bell repeated.

Eustace nodded.

Bell let go his wrist, palming the copper tube as he did, shook it speculatively, then tossed it to Andy Moser, who took one look and glowered, “When the gas melts the wax, what’s inside leaks out. What is it? Water?”

Eustace Weed bit his lip and nodded.

Bell pulled a notepad from his coat. “Do you recognize this fellow?”

Eustace Weed blinked at a drawing like you’d see in the newspaper.

“A saloonkeeper in Chicago. I don’t know his name.”

“How about this one?”

“He worked for the saloonkeeper. He took me to him.”

“And this one?”

“He’s the other one who took me to see him.”

“How about this man?”

Bell showed him a sketch of a grim-faced man, more frightening than the others, who looked like a prizefighter who had never lost a bout. “No. I never saw him.”

“This fellow is a Van Dorn detective who has lived for the past two weeks across the hall from Miss Daisy Ramsey and her mother. He shares his rooms with another fellow, a bigger fellow. When one has to go out, the other is there, across the hall. When Daisy goes to work at the telephone exchange, a Van Dorn man watches the sidewalk and another watches the telephone exchange. Do you understand what I’m saying to you, Eustace?”

“Daisy is safe?”

“Daisy is safe. Now, tell me everything. Quickly.”

“How do you know her name?”

“I asked you her name back in Topeka, Kansas. You told me, confirming what we were already turning up in Chicago. It’s our town.”

“But you can’t watch over her forever.”

“We don’t have to.” Bell held up the pictures again. “These two will be locked back in Joliet prison to resume serving well-deserved twenty-year sentences. This saloonkeeper is about to go out of business and open a small dry-goods store in Seattle, a city to which he is moving for his health.”

ON A REMOTE STRETCH of dun-colored ranchland between Los Angeles and Fresno, the Southern Pacific West Side Line that the air racers were supposed to follow crossed the tracks of the Atchison, Topeka amp; Santa Fe. Intersecting at that same point were local short-line railroads that served the raisin growers and cattlemen of the San Joaquin Valley. The resultant junction of rails, switches, and underpasses was so confusing that dispatchers and train conductors called it the Snake Dance. The Whiteway Cup Air Race stewards had marked the correct route with a conspicuous canvas arrow.

Dave Mayhew, Harry Frost’s telegrapher, climbed down from a pole and read aloud his Morse alphabet transcriptions.

“Josephine’s way in the lead. Joe Mudd had trouble getting off the ground. Now he’s stuck in a cotton field in Tipton.”

“Where’s her support train?” asked Frost.

“Keeping pace. Right under her.”

“Where’s Isaac Bell?”

“The Tulare dispatcher heard his motor sputtering when he saw Bell and Josephine fly over. No one’s spotted him since. The last dispatcher who spotted her said Josephine was flying alone.”

“Where is Bell’s support train?”

“Sidelined north of Tulare – probably where he went down.”

Harry Frost pulled his watch from his vest and confirmed the time. By this hour, the water in his gas should have made Isaac Bell smash.

“Get the auto,” he told Mayhew.

With decent luck, Bell was dead. But, at the very least, the Van Dorn posed no threat to Frost’s plan to shoot Josephine out of the sky and wreck Whiteway’s support train.

To Stotts, Frost said, “Move the pointer.”

Mike Stotts ran onto the Southern Pacific main line, rolled up the canvas arrow pointing north and unrolled it pointing northwest up the short line that angled toward the dry hills that rimmed the valley to the west. Then he threw the switch to divert Josephine’s train in the same direction.

Dave Mayhew drove a brand-new Thomas Flyer onto the short line. Frost and Stotts climbed in, and the three raced northwest.

THE ONLY NOISE ISAAC BELL HEARD was the wind humming in the wing stays as he volplaned his yellow machine in gently descending circles. Beef cattle grazed peacefully under him, and a flock of white pelicans stayed on course, proof that he was passing over the ground as silently as a condor.

A storm from the distant Pacific was surmounting the coastal mountains, and the shadow cast by his machine flickered and faded as the sun was covered and uncovered by cloud fragments racing ahead of the heavy thunderheads. As his shadow crept across the rolling hills in lazy curves, Bell maneuvered carefully so as not to let it fall on the Thomas Flyer racing ahead of a dust trail on the short-line tracks.

There were three men in the Thomas. Bell was too high in the air to identify them, even with his field glasses. But the massive bulk of the figure hunched in the backseat of the open auto, and the canvas arrow that had been shifted away from the main line, coupled with poor Eustace’s attempt to sabotage his engine, told him it had to be Harry Frost.

He had spotted the dust trail ten miles after he followed the canvas arrow at the Snake Dance junction and immediately shut off the noisy Gnome. Josephine was safe on the ground thirty miles back, fuming at the delay despite an official time-out sanctioned by Preston Whiteway to give Bell the opportunity to capture Frost.

Bell turned back toward the junction and restarted the Gnome. When he saw the long yellow line that was the Josephine Special, he swooped down to the train, skimmed the roof of the hangar car, which bristled with rifle-toting detectives, turned around again, and led the train after the Thomas, rising to only five hundred feet above the locomotive.

After ten minutes he thought that they would have caught up, but the tracks were empty and the dust trail gone. A broad dry creek appeared ahead, a dip in the rolling land, as the tracks began veering alongside the foothills of the Coast Range mountains. It was bridged by a long wooden trestle.

The tall detective held his control wheel in one hand and scrutinized the trestle with his field glasses. The maze of timbers would offer excellent cover for men with rifles. And they could have hidden the Thomas in its shadows. But he saw neither the men nor their auto. Suddenly he heard two sharp explosions – louder than the roar of the Gnome. He knew they weren’t gunshots. Nor had they come from the trestle but from directly beneath him, as if from the locomotive.

The big black Atlantic slowed abruptly. Its high drive wheels ground sparks from the rails as the engineer fought to stop his long train as fast as he could. The loud reports, Bell realized, had been caused by torpedoes – detonating caps of fulminate of mercury attached to the rails with lead straps to signal trouble ahead. When a locomotive passed over them, they exploded loudly enough for the engineer and fireman to hear over the roar of the firebox and the thunder of the steam.

Bell saw white smoke spewing from the brake shoes under every car, and the train clashed and banged to a halt halfway across the trestle. Instantly, the locomotive emitted five puffs of steam from its whistle. Five whistles signaled a brakeman to jump from the rear car – Preston Whiteway’s private carriage – and run back along the tracks waving a red flag to warn trains steaming behind it that the special had stopped suddenly for an emergency and was blocking the tracks. By then Bell had overflown the train and the trestle.

He saw the glitter of sunlight on glass.

In the same instant, he spotted the Thomas parked in the shadow of a rail-maintenance shack. The sun flashed again on a telescope sight. He counted two rifles braced on the roof of the shack, spitting red fire.