urpose, and now I unslung
them and managed to work them up above my shoulders, one in either
hand.

"I'm going to try to blow the entrance clear, men," I shouted. "The
instant I fling the bombs, drop! The fragments will be stopped by the
enemy crowding around us. One ... two ... three ... _drop_!"

The two bombs exploded almost simultaneously. The ground shook, and
all over the cavern masses of stone came crashing to the floor. Bits
of rock hummed and shrieked over our heads. And--yes! There was a
draft of cooler, purer air on our faces. The bombs had done their
work.

"One more effort and we're outside, men," I called. "The passage is
open, and there are only a few of the enemy before us. Ready?"

"Ready!" went up the hoarse shout.

"Then, forward!"

It was easy to give the command, but hard to execute it. We were
pressed so hard that only the men on the outside of the group could
use their weapons. And our captors were making a terrible, desperate
effort to hold us.

Two more of our men were literally torn to pieces before my eyes, but
I had the satisfaction of ripping holes in the heads of the creatures
whose tentacles had done the beastly work. And in the meantime we were
working our way slowly but surely to the entrance.

* * * * *

I glanced up as I dodged out into the open. That soft humming sound
was familiar, and properly so. There, at an elevation of less than
fifty feet, was the _Ertak_, with Hendricks standing in the exit,
leaning forward at a perilous angle.

"Ahoy the _Ertak_!" I hailed. "Descend at once!"

"Right, sir!" Hendricks turned to relay the order, and, as the rest of
the men burst forth from the cavern, the ship struck the ground before
us.

"All hands board ship!" I ordered. "Lively, now." As many years as I
have commanded men, I have never seen an order obeyed with more
alacrity.

I was the last man to enter, and as I did so, I turned for a last
glance at the enemy.

They could not come through the small opening my bombs had driven in
the rock, although they were working desperately to enlarge it.
Leaping back and forth between me and the entrance I could see the
vague, shadowy figures of the outside slaves, eagerly seeping up the
life-giving fumes that escaped from the cavern.

"Your orders, sir?" asked Hendricks anxiously; he was a very young
officer, and he had been through a very trying experience.

"Ascend five hundred feet, Mr. Hendric