Peggy shut off the exhaust, turning the explosions of the cylinder into a muffler.  In almost complete silence they winged upward.  Up, up, toward the fleecy clouds she had been lazily watching, but a short time before, from the hammock.

The Golden Butterfly had never done better.

“You’re a darling!” breathed Peggy confidentially to the motor that with steady pulse drove them upward and onward.

CHAPTER IV.

IN A STORM

Dwarfed to the merest midgets, the figures about the Prescott house waved enthusiastically, as the golden-winged monoplane made a graceful swoop high above the elms and maples surrounding it.  Other figures could be glimpsed too, now, running about excitedly outside the barn-like structure housing the Mortlake aeroplanes.

“Guess they think you are stealing a march on them,” drawled Lieut.  Bradbury.

A wild, reckless feeling, born of the thrilling sensation of aerial riding, came over Peggy.  She would do it—­she would.  With a scarcely perceptible thrust of her wrist, she altered the angle of the rudder-like tail, and instantly the obedient Golden Butterfly began racing through space toward the Mortlake plant.

The naval officer, quick to guess her plan, laughed as happily as a mischievous boy.

“What a lark!” he exclaimed.  “It’s contrary to all discipline, but it’s jolly good fun.”

Peggy turned a small brass-capped valve—­the timer.  At once the aeroplane showed accelerated speed.  It fairly cut through the air.  Both the occupants were glad to lower their goggles to protect their eyes from the sharp, cutting sensation of the atmosphere, as they rushed against it—­into its teeth, as it were.

Peggy glanced at the indicator.  The black pointer on the white dial was creeping up—­fifty, sixty, sixty-two—­she would show this officer what the Prescott monoplane could do.

“Sixty-four!  Great Christmas!”

The exclamation came from the officer.  He had leaned forward and scanned the indicator eagerly.

“We’ll do better when we have our new type of motor installed,” said Peggy, with a confident nod.  The young fellow gasped.

“This is the twentieth century with a vengeance,” he murmured, sinking back in his rear seat, which was as comfortably upholstered as the luxurious tonneau of a five-thousand-dollar automobile.

Like a darting, pouncing swallow, seeking its food in mid-air, the Golden Butterfly swooped, soared and dived in long, graceful gradients above the Mortlake plant.  Once Peggy brought the aeroplane so close to the ground in a long, swinging sweep, that it seemed as if it could never recover enough “way” to rise again.  Even the officer, trained in a strict school to repress his emotions, tightened his lips, and then opened them to emit a relieved gasp.

So close to the gaping machinists and the anger-crimsoned Mortlake did the triumphant aeroplane swoop, that Peggy, to her secret amusement could trace the astonished look on the faces of the employees and the chagrined expression that darkened Mortlake’s countenance.