y; "but Mr.
Wells--look at that red light, sir!"

Keith glanced rapidly at the location chart, ripping off his sea-suit
as he did. The fateful red stud was moving swiftly down on the
motionless green one. The men had surrounded McKegnie, laughing and
slapping him on the back, but the commander's terse orders jerked them
abruptly back to action.

"The rectifiers, Graham: clean out this stale air. Sea-suits off; at
emergency posts. Take the helm, Craig; you, Wetherby, trim the ship.
No, no, Cook--keep away from the controls!"

The _NX-1_ balanced herself; fresh air came rushing in, sweeping out
the stale. Keith stared at the location chart, waiting for the
submarine to be ready. The red light was almost upon them.

"Right!" he roared at last. "Diving rudder controls, Graham! Full
speed for the tunnel!"

* * * * *

At that moment the octopi ship swept into view, its full battery of
offensive weapons flaring forth. The paralyzing ray tingled again and
again over the control room. Someone laughed at its uselessness. The
violet heat ray leveled full at them, but the commander avoided it
with "Port ten, starboard ten! Maintain zigzag course to the tunnel."
He understood the enemy's weapons now; he was throbbing with the
fierce thrill of action. This duel was to be the climax of their whole
adventure. "And, by heaven," he promised, "it's going to be a fight!"

The other craft seemed to realize the _NX-1_ was now in expert hands.
She raced along to starboard for some minutes, her heat ray trying
vainly to steady on the American's weaving form. Wells wondered if the
king of the octopi was aboard her, in command; he thought perhaps the
ship had postponed her chase of McKegnie to pick him up. "I hope he
is!" the commander breathed, and fingered the torpedo lever. He had
some debts to pay.

The _NX-1_, engines working smoothly, proceeded on a desperate dash
for the tunnel that led to the outer sea. But the octopi ship
apparently knew what Keith intended, for she abandoned her offensive
rays, changed course a few degrees and slowly but steadily pulled
ahead. "Damn!" Keith exclaimed. "She'll get there before us!"

The dim shape dwindled on the screen, and before long her bulk had
disappeared entirely. Wells then could watch her swift, straight
progress only on the location chart.

* * * * *

Ten minutes later the funnel-like opening of the tunnel loomed on the