aid the captain. "Nearly every beast has its times for
going to drink; so we ought to get some inkling of what it is like at
the various springs."

They were not long in coming to one in a hollow beneath a great pile of
moss-grown rock down whose sides trickled the water to form at last a
good-sized pool of the most limpid kind; but the mossy boggy earth
around was untrodden, the water clear, and no trace to be seen of a
single footprint other than their own.

The water was delicious on that hot day in the steamy jungle, and the
band was refreshed--Mark having hard work to refrain from chasing some
gorgeous butterfly of green and gold, or with wings painted in
pearl-blue, steel, and burnished silver. At other times some lovely
kingfisher, with elongated tail, settled almost within reach. Then it
would be a green barbet, with bristle-armed beak and bright blue and
scarlet feathers to make it gay. Or again, one of the cuckoo trogons,
sitting on some twig, like a ball of feathers of bronze, golden green,
and salmon rose.

But this was not a collecting trip. Earnest investigation was the order
of the day; and after carefully taking their bearings the captain
pressed on, with their way always on the ascent and growing wilder and
more rocky.

This had its advantages as well as its disadvantages; for though the
path was from time to time one continuous climb, they were not compelled
to force their way through tangled growth, with trees bound together by
canes and creepers, as if nature were roughly weaving a stockade.

Another stream was passed rising out of a boggy patch of ground, and
here footprints were plentiful, but they were only those of birds that
had been down to drink.

Onward again, and to ascend a steep precipitous slope right before them
they had to descend into a dank, dark, gloomy-looking gorge, whose
vegetation was scarce, and yet the place seemed to grow hotter as they
went down.

A peculiar whistling sound came now from before them, and they stopped
to listen, with the day evidently growing hotter, for down in the gorge
there was not a breath of air; while as they listened the whistling grew
louder and was accompanied by another in a different key, the two
producing a curious dissonant sound for a few minutes, increasing
rapidly, and then ceased, to be followed by absolute silence, and then a
dull sound followed as if something had burst.

"Steam--a hot spring, I should say," exclaimed the cap