“No, I don’t think it’s that,” said Tom anxiously. “It looks to me as if the pilot were in some sort of trouble. Lost control, sick, or something. I’m going over to see.”

He turned the nose of his craft directly toward the strange plane and made for it at full speed.

The queer contortions of the plane still persisted, and Ned was by this time convinced that Tom was right. A thrill of horror went through them as the conviction grew upon them that they might be about to witness a tragedy. If the plane should dash to the ground from such a height, there was not one chance in a thousand that the luckless pilot would survive.

They could see by this time that there was only one man in the plane, which was a much larger craft than their own. They could see him working desperately to get his craft under control. Where the trouble lay, whether with the plane or the engine, they had no means of telling. But that the man was in deadly danger and knew it, there was no longer any room for doubt.

They had come within half a mile of the strange airship when the disaster they had been dreading happened. The plane suddenly turned its nose to the earth until it pointed directly downward. Then it fell like a plummet, down, down, into the midst of a forest, where it landed with a terrific crash and was lost to sight.

A cry of horror burst from Tom and Ned.

“Quick, Tom!” cried the latter. “Can’t you make a landing somewhere?”

“That’s what I’m looking for,” replied Tom, as his eyes swept the surrounding country in search of some open spot.

But he looked in vain. The woods extended for several miles in every direction. Here and there were small open places, but as Tom circled about, flying as low as he could without striking the tops of the trees, he saw that none of them was large enough to permit the landing of the plane.

“There’s but one thing to do,” he said in a tense tone, when this conviction had become certainty. “We’ve got to mark the location of this place so that we can find it when we come to it again. I’ll leave you to fix that in your mind. Now we’ll make straight for home, get out my roadster and try to get to the place as soon as possible. The chances are that the poor fellow is dead, but we’ll do all we can. You get busy on the radio, so that the car will be all ready for us to jump into the minute we get back to the works.”