The boys had succeeded in removing the man from the wreckage—­one glance about them told the girls that the wreck had once been an aeroplane—­and the man, who was elderly, lay quite still, looking up at them with sick eyes.

“Oh, can’t we get him up to the house?” cried Billie, clasping her hands in pity and looking appealingly at Mrs. Gilligan.  “Then we can send for a doctor—­”

But it was the hurt man himself who interrupted.

“I—­I’m all in,” he said, speaking with great effort.  “It won’t do any good to move me—­”

“But it might,” cried Violet, coming down and leaning compassionately over him while her eyes filled with tears.  “Do you think—­it would hurt—­too much—­”

“Come on.  Let’s try it, fellows,” said Teddy, speaking with sudden decision.  “We can’t leave him here to die, perhaps,” he added softly.  “We can at least make an attempt to save his life.”

He bent down, and, putting a hand under each of the man’s arms, lifted him slightly, eliciting a moan of pain.

“You take his feet, Chet, and, Ferd, you support his back,” he directed.  “Now then—­”

The boys started to obey, but at the first touch the man cried out in such pain that they were forced to put him down again.

“It’s something in here,” said the old fellow, while the girls and boys stood looking helplessly at him, not knowing what to do.  He put a hand over his left side.  “Something’s broken.  I—­I was trying to—­invent a new kind of aeroplane,” he went on jerkily, and in spite of the tragic circumstances the young folks felt a thrill of excitement as they realized that here perhaps was the secret of that strange humming noise that had so badly frightened and bewildered them.

“The second ghost,” murmured Teddy softly, as though to himself, but Billie, standing close beside him, heard.

“A new kind of aeroplane,” Chet prompted, gently but with an unusual light in his eye.

“Yes.  And this was its—­trial flight,” the old man said with a world of bitterness in his voice.  “The engine exploded.  I guess it shows that I’m pretty much of a failure—­in every way.”

“I don’t see why,” cried Billie, her warm heart eager to give him comfort.  “There may have been just some little thing the matter that you—­What’s that?”

“That” was the sound of running feet and a crackling of bushes, and the next minute two men burst out into the clearing.  They were red of face and breathless, and when they saw the old man and the wrecked machine they stood stock still and stared in consternation.

With a start the girls and boys recognized the men as those whom they had met in the woods that other day not so long ago—­the men who had so curtly ordered them to “go the other way.”

So the corn story was a fish story after all, and the old inventor’s vain attempt to make a new kind of flying machine was the key to all the mystery!