Archie caught up. “Good job, Tom. I’ll vouch for him.”

Bell was already heading for Josephine. She had climbed onto a crosspiece that connected the landing wheels to lean into her motor and was adjusting the carburetor with a screwdriver.

Bell said, “Those hinged appendages on the back of your wings appear to give you extraordinary control.”

She looked down at him with lively eyes. Hazel, Bell noticed, a warm green color in the sunlight, edging toward a cooler gray. “They’re called alettoni. That’s Italian. It means ‘little wings.’”

“Did they slow your airship’s descent by enlarging the wing’s surface?”

Returning her attention to the carburetor, she answered, “They deflect more air.”

“Do alettoni work better than warping?”

“I’m not sure yet,” she said. “They don’t always do what I want them to. Sometimes they act as a brake and slow me down instead of keeping me level.”

“Can they be adjusted?”

“The man who invented them is dead. So now we have to figure it out without his help.” She made a final adjustment, sheathed her screwdriver in a back pocket, jumped to the ground, and offered her gloved hand. “I’m Josephine, by the way. Who are you?”

“Sorry, I should have introduced myself. I’m Isaac Bell. I’m Van Dorn’s chief investigator.”

“My brave protectors,” she said with a frank and open smile.

She was tiny, Bell thought. Barely an inch over five feet tall, with a pretty upturned nose. Her direct gaze was older than her years, though she had a young woman’s voice, thin and girlish. “I’m pleased to meet you, Mr. Bell. I hope ‘chief investigator’ doesn’t mean Archie’s been fired?”

“Not at all. Archie is in charge of your personal safety. My job is to intercept your husband before he gets close enough to harm you.”

Her eyes darkened, and she looked fearful. “You’ll never catch him, you know.”

“Why not?”

“He’s too sly. He thinks like a wild animal.”

Bell smiled to put her at ease, for he saw that she was really afraid of Frost. “We’ll do what we have to to deal with him. I wonder whether you might give me any clues to his behavior. Anything that would help me run him to ground.”

“I can only tell you things about him that won’t help. I’m afraid I don’t know anything that will.”

“Then tell me what won’t help.”

“Harry is completely unpredictable. I never knew what to expect. He’ll change his mind in a flash.” As she spoke her eyes glinted toward the field where Joe Mudd’s red tractor biplane was taking to the air again, and Bell realized that she was assessing the competition as coolly as he would an outlaw in a knife fight.

“Can you tell me about friends he would call on?”