over?" asked his brothers.

"I suppose so. Wait, I'll go over and see."

Lantern in hand, Dick crossed on the beams of the wooden bridge. On the
opposite side he saw the same tracks of the tires in the dust and dirt.

"Yes, they came over!" he shouted.

"But the planking----" came from Tom.

"They must have thrown it into place to cross and then taken it up
again, so that they couldn't be followed,--that is, in a carriage, or an
auto, or on horseback."

"Yes, but they can't stop a biplane!" cried Sam, eagerly. "And this must
have taken time to do! We must be close behind them!"

"Let's get right after 'em!" put in Tom, and all three ran once more for
the _Dartaway_, and soon the quick explosions of the motor sounded on
the night air.

If the boys had been excited before, they were more so now, for they
realized that the touring car at the best could be but a few miles away.
Could they catch up to it before those running the machine had a chance
to slip them in the darkness?

"They must have their lights lit," said Dick. "They'd not dare run
without them. Look and see if you can't spot their headlights. Their
taillight we smashed with a pistol shot."

On and on swept the biplane. As the late moon came up higher, the way
became brighter, until they could distinguish the road below quite
plainly. But nothing like a touring car came into view.

"They must have had more time than we thought, or else they ran mighty
fast," remarked Dick, after several miles had been covered.

Presently they saw two bright lights coming towards them, down on the
road. At once Dick shut off the power, and allowed the biplane to come
down in the centre of the highway. Then Tom waved the lantern, and at
the same time all three lads took hold of their pistols.

It was a runabout that was coming up, an old affair, carrying two men
that looked like farmers.

"Hello, what's this, a hold-up?" cried one of the men. "By gum! if it
ain't an airship!" he gasped, as his machine came to a standstill in
front of the _Dartaway_.

"We'd like some information," said Dick, stepping forward and holding up
the lantern. "We are looking for a big enclosed touring car that came
this way. Did you meet it on the road?"

"A tourin' car? No, we didn't meet any kind o' an auto."

"None at all?"

"Nary a one," answered the second man.

"May I ask how far you've come?" went on Dick.

"We came from Plankville."

"How far is that?"

"About six mil