“He isn’t coming down,” cried Danny Grin in a tone of genuine disappointment.  “No chance for you on that one, Davy!  Too bad!”

Yet suddenly the rattling noise nearly overhead almost ceased as the engine was shut off.  Then gracefully the craft voloplaned and touched the ground, just inside the detachment’s line.

“Great work, Bowers!” cried Trent, recognizing in the Navy birdman a former classmate at Annapolis.

“Thank you, Trent.  You have an officer, haven’t you, to help me with field notes on this survey?”

“I have two,” smiled Trent, “but I am afraid I can spare only one.  Lieutenant Bowers, Ensign Darrin.  Hop aboard, Darrin!”

In a twinkling Ensign Dave had shaken hands with the birdman, adding: 

“At your orders, sir!”

Then Dave stepped nimbly up to the platform.  “Take a seat beside me, with your field-glasses ready.  Here’s your field note-book.”

At a sign from Lieutenant Bowers, the eager sailormen parted in front of the airship, which, after a brief run, soared gracefully once more.

Behind Lieutenant Bowers stood a sailor with a signal flag.

“Step to the rear,” Bowers directed, over his shoulder, “and wigwag back:  ‘O.K.  Stopped only for assistant.’  Sign, ‘Bowers.’

“Aye, aye, sir,” answered the signalman.  “Lieutenant Sherman’s airship is rising from the harbor, sir,” reported the signalman.

“Very good,” nodded Lieutenant Bowers, and kept his eyes on his course.  “Darrin, are you taking all the observations necessary and entering them?”

“Aye, aye, sir.”

“There’s the railroad bridge about which the admiral was so anxious,” said Bowers, presently.  “You will note that the bridge stands, but the railroad tracks have been torn up.”

“Aye, aye, sir,” Dave reported, after using his field glass.

“That’s one of the things we wanted to know,” Bowers continued.  “And keep an especially sharp 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.