“I’d give something to know what’s going to happen in the next half hour,” he murmured, grimly.

A magnificent panorama of mountains lay straight before them—a succession of forest-crowned slopes, of great precipices and gloomy-looking gorges.

Bob Somers turned toward his passenger; his interrogating look was immediately understood.

Cranny Beaumont nodded emphatically. His lips framed the words:

“Let her rip, Bob; go as high as you like.”

The big plane instantly began to rise, while its unrelenting pursuer, as if accepting this as an evidence of fear, uttered a wild screech. The startled lads had a quick view of a dusky form shooting ahead and above them. They involuntarily shrank back in their seats, as it circled around and swooped fiercely to the attack.

Bob Somers knew, and so did Cranny Beaumont, that a false movement of the controlling levers might place them in the greatest peril. The latter was prepared; he braced himself hard against the supports.

In another instant, the bird swept violently against the upper plane only a few feet from him, while beak, wings and powerful talons seemed to resolve themselves into a confused mass of pecking, beating and striking objects.

Crack, crack!

Two sharp reports came so close together as to be almost blended into one. A thin wisp of pungent smoke rolled backward. But Cranny Beaumont, even in those moments of danger, admired the great eagle too much to sacrifice its life. The bullets sped harmlessly into space.