“Are you very much hurt, Dad?” cried the younger of the two men, leaning anxiously over the old man.  Again the young folks were startled.  So one of the bearded men was the old man’s son!

“All in, Son, I guess,” answered the old man.  With a sigh he laid his hand over his left side and whispered:  “I’m all smashed to pieces.  The engine exploded.”

“Well, let’s see about that,” said the second of the two men, pushing the younger aside and beginning to rip open the old man’s shirt.

Up to that time neither of the men had thrown a glance in the direction of the wondering boys and girls—­in fact they gave every impression of not having seen them at all.

The older of the two men was working feverishly—­he seemed to be a doctor, judging from the skill with which he tapped here and pressed there, evidently trying to find out what bones were broken, if any.

And all the time the old inventor kept up a feeble moaning.

“He must be very much hurt indeed, or very, very old,” thought Billie as, with one hand clasped tightly in Laura’s and the other gripping Violet’s arm, she watched intently.

“Why, this isn’t so bad after all,” announced the man at last, looking up from his patient with a light in his eyes that made him look very boyish in spite of the beard on his face.  “Your father’s terribly bruised and battered up, Stanton,” he said, addressing the old man’s son, who had been looking on with strained attention, “but as far as I can see the only bones broken are a rib or two.  We’ll soon fix you up as good as new,” he went on, turning again to the old man.

The latter looked surprised and left off moaning.

“You mean I’m going to live?” he asked incredulously, adding with a faint little attempt at a smile:  “Why—­why, I was sure I was—­done for!”

“No indeed,” said the “doctor-person”—­as Billie had already dubbed him, rising briskly to his feet.  “You’ll live to fly many another aeroplane, Mr. Parsons.  Now will you let your son and me take you home?”

Such is the power of mind over matter, the inventor hardly made any outcry at all when his son and the “doctor-person” lifted him between them and started off through the woods.

As he turned about, the doctor’s eyes rested on the boys and girls and he stopped short, apparently really seeing them for the first time.

“Hello,” he said.  “I beg your pardon, but I scarcely noticed you,” adding, more by way of explanation than excuse:  “You see I was very much occupied.”

“Oh, we don’t mind,” said Billie truthfully, adding as the doctor turned toward her:  “Is there anything we can do to help the—­the inventor?”

“Oh, so he told you then,” said the doctor, with a vexed frown.  “No, thanks, there’s nothing you can do.  We’ll be back for the pieces of the aeroplane later.”

And without another glance the strange trio disappeared into the woods.