Once, twice, thrice those savage calls echoed far and wide, but with each repetition losing a portion of their terrors; and knowing now that prowling beasts surely were drawing nigh the camp-fire, the flying machine was abandoned by the trio, all drawing closer to the fire, which might prove no slight protection against attack.

Then followed a period of utter silence, during which their eyes roved restlessly around, striving to sight the four-footed enemy ere an actual attack could be made.

Professor Featherwit was first to glimpse a pair of greenish eyes in silent motion, and, giving a low hiss of warning to his nephews, that same sound serving to check further progress on the part of the wild beast, his short rifle came to a level, then emitted a peculiar sound.

Only the keenest of ears could have noted that, for only the fraction of an instant later followed a sharp explosion, the darkness beyond being briefly lit up by a yellowish glare.

"That's enough,—beware its mate!" cried the professor, keenly alert for whatever might ensue; but the words were barely across his lips when, with a vicious snarl, a furry shape came flying through the air, knocking Featherwit over as he instinctively ducked his head with arm flying up as additional guard.

Both man and beast came very near falling into the fire itself, and there ensued a wild, confused scramble, out of which the brothers singled their enemy, Waldo opening fire with a revolver, at close range, each shot causing the lion to yell and snarl most ferociously.

A cat-like recovery, then the fatal leap might have followed, for the confused professor was rising to his feet again, fairly in front of the enraged brute; but ere