Now they shot above the strip of white beach, and, below them the pleasant meadow-lands and patches of verdant woods began to show once more.

All at once, the sign for which Mortlake had been watching so anxiously manifested itself.  A tiny curl of smoke ascended from one of the cylinder-heads.  A smell of blistering, burning paint was wafted back to the nostrils of Lieut.  Bradbury.

“I thought so,” he said; “overheating already.  Better slow down, Mortlake.”

Mortlake glanced back.  The Golden Butterfly, much diminished in size now by the distance, still hung doggedly on his heels.

“I’ll give her more air,” he vouchsafed stubbornly, “that ought to cool her off a bit—­that and advanced spark.”

He manipulated the necessary levers, but before many minutes it became apparent that, if urged at that rate, the Silver Cobweb would never reach Sandy Beach without a break-down.

“Hadn’t you better shut down a bit?  That paint’s blistering, as if the cylinders were red-hot.”

Much as he disliked to interfere with the operation of the aeroplane, the young officer felt that it was necessary that some means should be taken to compel Mortlake to reduce speed.  If the engine became so overheated that it stopped in mid-air, they might be caught in a nasty position, where it might be impossible to volplane—­or glide—­downward, without the aid of the engine.

“It’s all right, I tell you,” said Mortlake stubbornly.  “We’ll beat those cubs into Sandy Beach, or——­”

Or what, was destined never to be known, for at that instant, with a splutter and a sigh, the overheated engines, almost at a red-heat, stopped short.  The propeller ceased to revolve, and the aeroplane began to plunge downward with fearful velocity.

But Mortlake, no matter what his other faults, possessed a cool head.  The instant he lost control of the motor, he seized the warping levers, and began manipulating them.  At the same time he set the rudder so as to bring the Silver Cobweb to earth in a series of long spirals.  The maneuver was that of volplaning, and has been performed successfully by several aviators whose engines have suddenly ceased to work while in mid-air.  The young officer watched approvingly.  Whatever else Mortlake might be—­and Lieut.  Bradbury had not taken a violent fancy to him—­he was a master of the aerial craft.

Despite the mishap to the engine—­caused by his own carelessness—­Mortlake managed to bring the Silver Cobweb to a gentle landing in a broad, flat meadow, inhabited by some spotted cows, which fled in undignified panic as the monster, silent now, swooped down like a bolt from the blue.

The instant the Silver Cobweb came to rest Mortlake’s restless eyes glanced upward.  He was hoping against all common sense that the young Prescotts had not seen his mishap, or at least that they would pass on above him unnoticing.  His first glance showed him the Golden Butterfly still steadily plugging along, and a moment later it became apparent that they had seen the sudden descent of the Cobweb, for the aeroplane was seen to dip and glide lower, much as a mousing hawk can be seen to do.