Tom was proud of his ability to execute that difficult feat known as a “nose-dive.”  More than once it had extricated him from a “pocket” into which he found himself placed by circumstances, with three or more enemy planes circling around and bombarding him from their active guns.

At such times the only hope of the attacked pilot lay in his ability to drop down as if his machine had received a fatal blow and when once far below the danger point again to recover an even keel.

Jack never doubted what the result would be, having the utmost confidence in his comrade.  The wind rushed past his ears as they pitched downward; and just when objects on the ground loomed up suggestively there was the expected sudden shift of the lever, a consequent change in the pointing of the plane’s nose, and then they found themselves on the new level, with the motor again humming merrily.

Jack was on the alert and quickly discovered the object that just then enlisted their whole attention.  As he had suspected when using the glasses from the higher level, it was a Yankee bomber that lay partly hidden among the bushes where it had fallen.  He could easily see the Indian head marking the broken wing.

The pilot was sitting near by as though unable to make a run for it, although Jack imagined he must suspect the approach of danger, for he gripped something that glinted in the sunlight in his right hand.  It was, of course, an automatic pistol.

Looking hastily around Jack glimpsed the creeping figures of the two Germans who, having seen the fall of the Yankee plane, must have come out from some place of concealment and were bent on finishing the pilot, or at least taking him prisoner.  They had almost reached a point where it would have been possible for them to open fire on the wounded American.

Jack looked in vain for any second figure near the fallen plane.  If the pilot had had an observer with him, which was most likely, considering the fact that he had been using a bombing machine, the latter must have been dispatched for relief some time before.

“There they are, Tom!” burst from the one who crouched close to the machine gun, and pointing as he spoke.  “Swoop down and let me give them a volley!”

The Huns evidently realized what was coming, and feared that their intended victim might after all escape their hands.  Even as Jack spoke there came a shot from below, and a bullet went screaming past close to the ears of the Air Service Boys.  It was followed by a second and a third in quick succession.

What the marksmen hoped to do was either to kill the pilot or else to strike some vulnerable part of the engine, thus disabling it and wrecking the plane.  Those were chances which had to be taken continually; but as a rule the rapidity of flight rendered them almost negligible.

Jack waited no longer.  The two men were about to fling themselves behind friendly trees, and but a small chance remained that he might catch them before they were able to shield themselves by these close-by trunks.