felt, as
he blew a long and shrill note again, that he would be able to guide the
herd into safety.

"Why are they not on the lookout?" groaned the boy, for his progress was
painfully slow; "they ought to see that something is wrong." But he was
ignorant of the fact that nothing was visible from the lookout but
himself and the animals trotting about playfully as they kept pretty
close to the wounded mustang.

An arrow again, and another, each wonderfully near, but no harm was
done. Then another which fell with a dull thud, and was followed by a
wild scream which startled the herd into disorder, sending the mules
helter-skelter, kicking and plunging, all but one, which galloped away
by itself, turning its head the while to bite at an arrow which had
buried itself in its back.

That strange scream had done what Chris's whistle failed in, drawn
attention to something being wrong, while directly after a little puff
of smoke darted from the upper terrace, followed by its report and the
reverberation of echoes. Then another shot, and another, and no more
arrows fell, though Chris in his slow progress suffered as much agony as
if they had still been dropping all around.

But now the doctor came running out, followed by Wilton, and under the
cover of a few more shots the little herd was driven in, slowly enough,
for the wounded mule progressed more and more slowly till it hung back
close alongside of Chris's mustang, showing that it was badly hurt.

"Only enough to prove that the enemy are well on the watch," said the
doctor, after he had seen to the wounded mule, "and a warning to us that
we must not relax our care."

Griggs had by this time descended from the terrace, it having been his
rifle that had put an end to the coming of the arrows.

"Hardly thought they could have shot so far," he said; "but after all,
they didn't get an arrow much more than half-way here. Say, didn't do
you much good, Master Chris, hurrying back like that."

"I'm afraid it's the mustang that has suffered," said Chris. "I didn't
hurt, only it was dreadfully hard to find that I couldn't run."

"You ought to be very thankful that you can walk, Chris," said the
doctor quietly. "It is next door to marvellous that you should have
escaped without a broken bone. But now then, Griggs, matters begin to
look serious. What is to be done?"

"That's just what I have been thinking, sir. The enemy isn't a bit
satisfied, and the next time they b