ck. Graham swore viciously, but Wells' masklike face
showed no slightest change of expression....

A voice rang in Keith's headphones. "Tough, Keith! Better luck next
time!" Then the commander winced. He simply could not answer Hemmy
Bowman; could not answer that fine, brave voice....

* * * * *

The stern torpedoes were gone. The tubes could not be reloaded, for
the paralyzing ray bound the men to the control room. That left them
two torpedoes in the bow.

The violet heat ray kept fingering hungrily on their outer hull, and
every man knew that the plates were weakening under the steady strain,
which was only lessened by the _NX-1's_ constant zigzagging. The
control room was very hot. Both ships were now a full mile from the
tunnel entrance. Keith plunged the _NX-1_ down, swung her around, to
bring his bow tubes to bear, and zigzagged upwards.

It was obvious that the octopi craft had been alarmed by the terrific
explosion. They now adopted tactics similar to the American ship's,
and for awhile both submarines circled cautiously, maneuvering for an
opening.

"If only we could keep the ship steady!" Graham muttered. "But then
that heat ray'd get us!"

The commander kept his eyes on the teleview. Again and again the
violet shaft pronged at them. The heat grew stifling. Sweat was
pouring from all the men's bodies. Every face was strained and taut.

"Starboard full!" Wells said suddenly. "A little up, Graham!" He had
seen a chance; the octopi craft was slightly above, and in a moment
would pass directly in the line of the bow tubes. The _NX-1_ stuck her
nose up, swung rapidly to the right. Keith pulled back the firing
lever, releasing one torpedo.

The long messenger of death hurtled straight for the enemy's hull.
They watched its course breathlessly....

"My God!" the first officer groaned. "Could they see it coming?" For
the octopi submarine had swung to one side, neatly dodging the
speeding tube of dynamite.

"One left!" he added bitterly. "One left!"

* * * * *

A desperate plan formed in Keith Wells' mind. His last torpedo simply
had to strike the mark; he could take no chances with it. He motioned
the haggard-faced Graham to him.

"There's only one thing left to do," he said quietly. "We've got to
deliberately face that heat ray; chance its puncturing our plates."

"How do you mean, sir?"

"Get in very close, so as to make our last torp