"But We're falling, Tom!"

"I know it. We've done it before. I'm going to volplane to earth."

This, it may be explained, is gliding downward from a height with the
engine shut off. Aeroplanists often do it, and Tom was no novice at the
art.

They shot downward with less speed now, for the young inventor had
thrown up his headplanes to act as a sort of brake. Then, a little later
they made a good landing in a field near a small house, in a rather
lonely stretch of country, about ten miles from Shopton, where Tom
lived.

"Now to see what the trouble is," remarked our hero, as he climbed out
of his seat and began looking over the engine. He poked in among the
numerous cogs, wheels and levers, and finally uttered an exclamation.

"Find it?" asked Ned.

"Yes, it's in the magneto. All the platinum bearings and contact
surfaces have fused and crystallized. I never saw such poor platinum as
I've been getting lately, and I pay the highest prices for it, too. The
trouble is that the supply of platinum is giving out, and they'll have
to find a substitute I guess."

"Can't we go home in her?" asked Ned.

"I'm afraid not. I've got to put in new platinum bearings and contacts