lookout, Ensign, for any signs
of Mexican forces, hidden or in the open."

But, though Dare looked constantly, he saw no indications of
the Mexican column with which General Maas had retreated.

"Too bad about Cantor of your ship," murmured Lieutenant Bowers,
a little later. "Though the forces have been searching for him
for three or four days he can't be found anywhere. It must be
fearful to be tried for treason to one's flag. I am hoping that
Cantor will be brought in dead. Under such charges as he faces,
there's more dignity in being dead."

"Much more," Dave assented, in a low voice.

On and on they flew. Once, when Dave sighted moving persons in
the distance, Bowers drove the craft up to three thousand feet above
the earth. But soon, under the glass, these suspects turned out
to be a party of wretched refugees, hurrying, ragged, barefooted,
starving, gaunt and cactus-torn, to safety within the American lines
at Vera Cruz.

For many miles Bowers's craft flew inland, and much valuable information
was picked up, besides the data from which any naval draughtsman
could construct a very good map of that part of the country.

At last Lieutenant Bowers turned back.

Suddenly Dave exclaimed, "Hullo! There are two men coming out
of the adobe house ahead."

The house in question was out about four miles beyond Trent's
station.

Dave kept his glass turned on the two men on the ground, at the
same the trying to conceal the glass from their view.

"They haven't rifles," he told Lieutenant Bowers. Then, as the
aircraft passed and left the adobe house to the rear, Darrin
bent over and whispered something in Bowers's ear that the signalman
behind them could not hear.

CHAPTER XXIII

THE DASH FOR THE TRAITOR

A Little later the hydro-aeroplane returned to Lieutenant Trent's
position.

Dave placed in the hands of the lieutenant the field note-book, which
had been so carefully kept that any officer could draw a map from
it at need.

Lightly the big airship touched the earth just inside Trent's
line. Dave, shaking hands with his temporary commanding officer,
added:

"Thank you for something I've always wanted---a flight over a
real enemy's country."

"I've greatly enjoyed having you with me," Lieutenant Bowers responded.
"Trent, you've obliged me hugely by giving me so good an assistant.
Good-bye, fellows."

The birdman was again several hundred feet up in the air.

"What kind of a trip wa