The cab flew through Passy, crossed the Seine and reached the Issy-les-Moulineaux aviation ground in ten minutes.
None of the aeroplanes was out, for there was a stiff breeze blowing. Don Luis ran to the sheds. The owners' names were written over the doors.
"Davanne," he muttered. "That's the man I want."
The door of the shed was open. A short, stoutish man, with a long red face, was smoking a cigarette and watching some mechanics working at a monoplane. The little man was Davanne himself, the famous airman.
Don Luis took him aside and, knowing from the papers the sort of man that he was, opened the conversation so as to surprise him from the start:
"Monsieur," he said, unfolding his map of France, "I want to catch up some one who has carried off the woman I love and is making for Nantes by motor. The abduction took place at midnight. It is now about eight o'clock. Suppose that the motor, which is just a hired taxi with a driver who has no inducement to break his neck, does an average of twenty miles an hour, including stoppages—in twelve hours' time—that is to say, at twelve o'clock—our man will have covered two hundred and forty miles and reached a spot between Angers and Nantes, at this point on the map."
"Les Ponts-de-Drive," agreed Davanne, who was quietly listening.
"Very well. Suppose, on the other hand, that an aeroplane were to start from Issy-les-Moulineaux at eight o'clock in the morning and travel at the rate of sixty miles an hour, without stopping—in four hours' time—that is to say, at twelve o'clock—it would reach Les Ponts-
