of
his immense wings, had settled right on the tail of the machine, where
he clung with his sturdy talons, threatening to prevent Paul from
manipulating the rudder. When Bob called Tom's attention to this
alarming situation, the latter joined him at the rear window of the
cabin. Tom took careful aim, pulled the trigger, and the condor fell
with a broken wing, uttering hoarse cries until the clouds below
swallowed him up.

Two more of the fierce creatures were killed before the remaining birds
were frightened off. It was with a sigh of relief that Paul now
resumed his descent to lower levels.

When presently they emerged out of the last cloud, and could see the
green earth below them once more, they were across the last chain of
mountain they would encounter in South America. They gazed with their
glasses on all sides, and checked up their position on the chart,
although in doing this they had great difficulty on account of a
curtain of thin fog which hung over the land, and only a very low
altitude of about five hundred feet would allow of it at all.

As soon as they were sure of their bearings they again took a searching
observation in quest of the rival airplane, but no sign of it could
they see.

"They're probably quite a bit ahead of us by this time," observed John;
"but now that we're through the last chain of the Andes we can make
better speed. Shoot her up to two thousand feet, Buddy. We'll set our
course for Georgetown by compass."

Paul bore upward, and at the level mentioned he straightened the
machine with her nose once more pointed eastward, and the compass hand
pointing along the left wing of the machine.

It was now growing dark. Not knowing whether this was caused by the
closing in of the clouds or the natural declension of the sun, Bob
looked at his watch. To his surprise he found it was seven o'clock
Panama time, which would make it probably close to nine in their
present locality. Night should now be upon them.

As it had been decided to let John and Tom operate the night shift, at
least for the first few days, John now took his trick at the throttle,
changed to the fresh engine, and Bob and Paul turned into their
hammocks for the first sleep aboard the airplane. They were both
pretty tired, as each had spent several hours at the helm that
afternoon, and it was only a few minutes before the gentle rocking of
the plane on the billows of air had sent them into a sound oblivion.
Just