“There is an old saying about politicians,” remarked the lieutenant, “to the effect that few die and none resign.  That can never be said about aviators, because, while none of them ever give it up for good, the fatalities have been very numerous.  But when that stability device which your friend believes he has invented, but which he may have read about somewhere and unconsciously copied, comes into general use, we hope the deaths will become much less frequent.  I am using a stability device right now on this monoplane.  It was installed by the firm that patented it.  You can see how it acts automatically to steady the machine, no matter how we move about.  And I am almost as safe up in a squally wind as on a calm day.”

He took Hugh much higher than he had the others, as the barograph that was within seeing distance from their seat told the boy, who had learned how to read its figures.

Half an hour later they came back toward the field again, and descended to lower currents.  The picture Hugh gazed upon as he looked down would never be forgotten.  He could see for miles and miles in every direction; and how different the country looked from anything he had ever imagined!

All at once Hugh made a discovery.

“I am almost certain I saw two men hide themselves in that patch of bushes ahead there,” he hastily told the pilot; “and it seemed to me that they must be the pair of spies who have been giving you so much trouble.  They were creeping toward the camp as if they meant to try and steal in the back way.”

The lieutenant laughed as though pleased.

“Good for you, Hugh,” he remarked.  “Those sharp eyes of yours let nothing escape.  Now we’ll just circle around a bit and give those precious foreigners the scare of their lives.  I happen to have a supply of small experimental bombs along, which are heavy enough to frighten them into believing one of the new explosives may follow, after we have the range.  Watch out for some fun, my son!”

CHAPTER XI

GOOD-BY TO THE FOREIGN SPIES

When Hugh saw the air pilot reach back and take a small black object from a box attached to the body of the monoplane close to the gasoline tank, he knew that those skulkers below were in for a lively time of it.

Undoubtedly they had been creeping toward the rear of the camp with the hope either of picking up valuable information, or finding a chance to make way with precious plans connected with this latest war airship which Uncle Sam was trying out, and which possessed features far in advance of anything known abroad.

At a certain second, when he judged that he could drop the bomb very close to where the couple were secreted, the lieutenant hastened to do this.  Almost immediately afterwards he caused the monoplane to make a curve, so that they would be in shape to circle around that particular spot and repeat the bombardment as long as the supply of missiles held out.