shrinking sense of dread.

Everything was thrilling: the golden-spangled water looked so black, and
the darkness around so deep, while from the Grand Chaco, the great,
wild, untrodden forest across the river stretching away toward the
mighty Andes in the west, the shouts, growls, and wails suggested
endless horrors going on as the wild creatures roamed here and there in
search of food.

_Plash_! right away--a curious sound of a heavy body plunging into the
river, but with the noise carried across the water, so that it seemed to
be only a few yards away.

"What's that?" whispered Rob.

"Can't tell for sartain, my lad, but I should say that something came
along and disturbed a big fat 'gator on the bank, and he took a dive in
out of the way. I say! Hear that?"

"Hear it?" said Rob, as a creeping sensation came amongst the roots of
his hair, just as if the skin had twitched; "who could help hearing it?"

For the moment before Shaddy asked his question a blood-curdling,
agonising yell, as of some being in mortal agony, rang out from across
the river.

"Ay, 'tis lively. First time I heered that I says to myself, `That's
one Injun killing another,' and I cocked my rifle and said to myself
again, `well, he shan't do for me.'"

"And was it one Indian murdering another in his sleep?"

Shaddy chuckled.

"Not it, lad. Darkness is full of cheating and tricks. You hears
noises in the night, and they sound horrid. If you heered 'em when the
sun's shining you wouldn't take any notice of 'em."

"But there it is again," whispered Rob, as the horrible cry arose, and
after an interval was repeated as from a distance. "Whatever is it?"

"Sort o' stork or crane thing calling its mate and saying, `Here's lots
o' nice, cool, juicy frogs out here. Come on.'"

"A bird?"

"Yes. Why not? Here, you wait a bit, and you'll open your eyes wide to
hear 'em. Some sings as sweet as sweet, and some makes the most gashly
noises you can 'magine. That's a jagger--that howl, and that's a lion
again. Hear him! He calls out sharper like than the other. You'll
soon get to know the difference. But I say, do go and have a sleep now,
so as to get up fresh and ready for the day's work. I shall have lots
to show you to-morrow."

"Yes, I'll go and lie down again soon. But listen to that! What's that
booming, roaring sound that keeps rising and falling? There, it's quite
loud now."

"Frogs!" said Shaddy promptly. "There's so