“Well, I’m getting that way mighty fast, thanks to your hints, and the knowledge of how it pays, when you’re taking your life in your hands every time you go up in one of these heavier-than-air outfits,” was what the other Bird boy observed, with what was a thoughtful look, for him; because, as a rule, Andy appeared to be a merry chap, and laughing much of the time.

Within half an hour they had successfully landed at the place indicated, and which had witnessed the coming and going of the young aeronauts on numerous occasions.

Here at least they could remain and take things easy while waiting for the morning to slip along, so that eleven would roll around.  Little danger of their being bothered by curious persons here; indeed, the boys had never yet known a solitary man or boy to come around the place.

They could look up while lying there on their backs, and watch the fleecy clouds sailing swiftly past the lofty crown of the rocky mountain.  And how vividly there came into their minds memories of lively times which they themselves had experienced up there on the summit of old Thunder top.

They spoke of them now, as they lay stretched out on the soft turf, and watched the two white headed eagles soaring far up in the blue heavens, around and around in circles, without ever seeming to flap their great wings.

Once the young aviators had engaged in a terrible conflict with those two mighty birds, on the crown of the mountain, where they had landed with their aeroplane, and been looked upon as intruders by the eagles, possibly under the belief that they entertained hostile intentions toward the fledglings in their nest that was built amidst the crags, close to the tip of the lofty peak.

Frank and Andy often spoke of that thrilling episode, but never without some sort of little shiver, because it had been a serious time with them since one blow from those powerful wings might have toppled them over the edge of the dizzy height, and sent them to their deaths.

But they had succeeded in beating their feather antagonists off by the aid of clubs which they wielded with vigor; and after the eagles learned that no harm was intended to their young by these bold navigators of the upper air currents, they came to have more respect for the strange winged thing that came humming up from the earth on more than one occasion.

When eleven o’clock came around, the boys were off again, and headed toward the northern end of the lake.

Of course they kept close down to the treetops, because, once they discovered the opening, they would wish to drop into it as easily as possible.

Suddenly Andy, who was on the lookout, while Frank paid more attention to the easy working of the motor, and the steering of the hydroplane, uttered an exclamation of satisfaction.

“I see it, dead ahead!” he remarked, in a satisfied tone.  “We made a bee line to the place from the foot of the mountain, Frank.  And unless I’m away off in my guess, the farmhouse lies over yonder beyond the trees; so nobody’s apt to see us come down; and we can make any sort of yarn we want, to explain just why we’re here right now.”