had
replied with a well-directed arrow that made me wince, it was so near my
head.

By this time I had reloaded and was taking aim again with feverish
eagerness, when all at once a great stone crashed down from above and
swept the savage from the ledge where he knelt.

I looked on appalled as the man rolled headlong down in company with the
mass of stone, and then lay motionless in the bottom of the little
valley.

"Who is it throwing stones?" drawled Jack slowly. "That was a big one,
and it hit."

"That could not have been an accident," said the doctor; "perhaps Aroo
is up there."

"I only hope he is," I cried; "but look, look! what's that?"

I caught at the doctor's arm to draw his attention to what seemed to be
a great thickly tufted bush which was coming up the little valley
towards us.

"Birnam wood is coming to Dunsinane," said the doctor loudly.

"Is it?" said Jack Penny excitedly. "What for? Where? What do you
mean?"

"Look, look!" I cried, and I pointed to the moving bush.

"Well, that's rum," said Jack, rubbing his nose with his finger. "Trees
are alive, of course, but they can't walk, can they? I think there's
some one shoving that along."

"Why, of course there is," I said.

"Don't fire unless you are obliged," exclaimed the doctor; "and whatever
you do, take care. See how the arrows are coming."

For they were pattering about us thickly, and the blacks on our side
kept sending them back, but with what result we could not tell, for the
savages kept closely within the cover.

It was now drawing towards evening, and the sun seemed hotter than ever;
the whole of the sultry ravine seemed to have become an oven, of which
our cavern shelter was the furnace. In fact the heat was momentarily,
from the sun's position, and in spite of its being so long past the
meridian, growing more and more intense.

Jack Penny had of late grown very silent, but now and then he turned his
face towards me with his mouth open, panting with heat and thirst, as
uneasily as his dog, whose tongue was hanging out looking white and dry.

"Is there any water there?" said the doctor suddenly, as he paused in
the act of reloading.

"Not a drop," I said, dismally.

"Oh! don't say that," groaned Jack Penny. "If I don't have some I shall
die."

"It will be evening soon," said the doctor in a husky voice, "and this
terrible heat will be over. Keep on firing when you have a chance, my
lads, but don't waste a sh