e time; but Frank had been figuring on
this and fixed it in his mind.

Even after the start he felt more apprehensive than he allowed the
others to see, for this was after all an experiment. Aviators have gone
up with two passengers and in monoplanes, too, but the limit of their
stay aloft had never exceeded two hours, for the strain is very great.

So Frank hoped to find places where they might drop down to rest, thus
making the journey in easy stages.

He believed they had plenty of gasoline to see them through, for an
additional supply had been carried when starting from the neighborhood
of the boat.

But once they were afloat he realized that he had been borrowing
needless trouble, for the gallant little aircraft just acted beautifully
and seemed to be able to speed merrily along with two passengers almost
as well as with but one.

Of course there were many chances for trouble. There always are when
traveling in an aeroplane, since the least thing that goes wrong means a
descent or a fall.

Frank tried no lofty flight. He kept close above the tree tops, content
to make steady progress in the direction where his little compass told
him they would find the river.

Once away from the mountainous country and they were able to descend to
still lower levels, where the chilly air changed to hot, and there were
signs of life among the trees below--birds, monkeys and other natives of
the wilds showing themselves at times.

It must have been a glorious sensation to the old aeronaut to be thus
speeding along in a modern, up-to-date airship, after his enforced
idleness for so long. Again and again did he express himself in that
way, as he gazed over the expanse of country, and then allowed his eyes
to rest fondly on the form of his boy, more dear to his heart than ever
after what had happened.

"I think I see an open place beyond," remarked Frank, after they had
been moving something like two hours after leaving the high
plateau. "And it might be wise while we have the chance to go down and
look things over. Then we will feel fit for another spell of work."

Accordingly the aeroplane was headed downward. They circled the opening
once or twice in order that the pilot of the aircraft might get his
bearings perfectly, and then he headed for the ground.

Even as they were just approaching the earth Frank heard Andy give one
of his customary exclamations, such as announced an important discovery.

"Frank, there's the