d
it was evident that their enemy was listening.

"I'm going on, Ramsden," said the boatswain. "Come along!"

"All right, sir. Join you as soon as I've got my prisoners."

"Hold 'em tight," shouted the boatswain, and then there was a loud
rustling sound, followed by the words faintly heard, "Look sharp. It's
of no use fooling there."

Don could hear Ramsden mutter something, but he did not seem to be
coming on; and mastering the dull, sluggish feeling, accompanied by a
throbbing headache, the lad stole cautiously back to where he could look
round and see their approaching enemy between them and the light.

To his intense surprise he found the man had his back to them, and was
retiring; but as he watched, Ramsden made an angry gesticulation, turned
sharply and came on again, but seemed to catch his foot against a
projecting piece of rock, stumble and fall forward, his cutlass flying
two or three yards on before him with a loud jingling noise.

What followed riveted Don to the spot.

CHAPTER THIRTY ONE.

GOOD FOR EVIL.

Ramsden struggled to his feet as if with an effort, and stood holding
his hand to his head, evidently hurt. The next moment he stepped
forward, staggering slightly, stooped to pick up his cutlass, and fell
forward, uttered a groan, rose up again, and fell down once more, this
time to lie without motion.

"Jem," whispered Don, "look at that!"

"Was looking," whispered back Jem. "Hit his head; sarve him right."

Ramsden did not move, and the two fugitives stood anxiously watching.

"What shall we do?"

"Wait! He'll soon come round and go. May as well sit down."

Jem lowered himself to a sitting position, and was in the act of trying
to rest on his elbow when he gasped quickly two or three times, and
caught at Don, who helped him to a kneeling position, from which he
struggled up.

"Hah!" he ejaculated; "just as if some one caught me by the throat. Oh,
how poorly I do feel. Just you put your head down there, Mas' Don."

Don stood thinking and trying to grasp what it meant. Then, with some
hazy recollection of dangers encountered in old wells, he bent down
cautiously and started up again, for it gradually dawned upon both that
for about two feet above the floor there was a heavy stratum of
poisonous gas, so potent that it overcame them directly; and it was into
this they had plunged as soon as they had stooped down.

"Why, Jem," panted Don; "it stops your breath!"

"Stops