t. The wrists of the suit were very flexible, permitting
the freest motion.

Once in the suit, Hemmy smiled through the still-opened face-shield.

"Got the depth charge ready, Keith? Make it fast--that cavern's
near!... Good!"

* * * * *

Silently the commander fitted the black bomb to his friend's
shoulders. It was timed to fire a minute after being set. A long wire
hook craned from its top, and this hook Bowman would fasten on the
hawser arm.

"Without Sparks, I guess I'll have to communicate with you through
portable," Keith said, and quickly donned one of the tiny portable
sets.

"Right. Ready, Keith."

Bowman started his awkward, crawling progress up the ladder into the
conning tower just above, Keith helping from behind. When they stood
before the exit port on the lee side, Wells shot back its bolts and
the door swung open, revealing the black emptiness of the water
chamber. The commander gazed for a second into Bowman's eyes. The
moment had come.

Keith turned his head away, felt a hand grip his. He wrung it
tightly....

Bowman clumped into the chamber.

The commander closed and locked the door, and he heard the streaming
water pour in as Hemmy turned the valve. Then Wells sped down the
ladder and tilted the diving and course rudders of the submarine.

She swayed daintily over to port; held there. A moment later the
recurring electric tingle brushed him. Had the enemy seen Bowman
leave? Had the ray struck him down?

He glared into the teleview. "Thank God!" he breathed. For Hemmy had
already slid down the _NX-1's_ smooth hull and was safe on the
sea-floor beside her.

"Everything right?" Wells asked, speaking into the microphone of his
portable.

"All O.K.," came the answer. "Going forward now. Kelp thick as hell."

* * * * *

Keith's eyes bored at the screen. This misshapen monster who was his
friend! Almost obscured by bands of thick-leaved kelp the yellow form
moved, hands clearing a pathway through the weeds. Slowly but surely
he made for the bow of the submersible.

"Hard going, Keith. God--the cavern's right ahead!"

It was ghostly to hear Hemmy's warm voice from the lifeless solitude
outside. Breath coming quickly, Wells watched the silent scene--the
cleft in the wall of rock overshadowing everything now. The diver
fought ahead, gaining inch by inch.

Now, save for occasional clumps of weed, he was exposed to the
enem