ship could be sent
out from Mars. He'll come on till he's within range of the
beam-thrower, and the Martian will aim, press the trigger and the
Earth ship and her crew of a half a thousand brave lads will be
star-dust."

"Oh God!" Jim was white-faced. "Isn't there anything we can do? Maybe
if he doesn't get our all-clear signal he'll sheer off." This was
clutching at straws.

"Why should he? He must know how short-handed we are, and will simply
think we're not on watch, or that our signal lights are out of order.
Matter of fact, if he were at all suspicious he should be alternating
his course right now--and he hasn't. Look."

Seemingly motionless, but really splitting the ether with terrific
speed, the warship was coming straight on to garrison the beleaguered
post. She had never wavered from her straight course for the Dome. The
little group was silent, watching the help that was coming at last,
coming too late.

* * * * *

From below there came a thunder of sound. Jim slid down the stairs. An
irregular disk on the wall was glowing cherry-red from the heat of the
blow-torch without, and the metal was quivering under the Mercurian's
sledge-hammer blows. "Darl's right," he almost sobbed as he gazed
helplessly. "They'll be through in no time. The Dome's gone, we're
gone, the space ship's gone!"

"Let me pass, Jim." Thomas' quiet voice sounded behind him. Holcomb
turned. His leader was in a space suit, the helmet still unfastened.

"Blazes! Where the devil are you going?"

"Here, cover me with this till I reach the gyrocopter, then get back
quick, and seal the air-lock." Darl thrust into Jim's hand the ray-gun
he had previously reserved. "There's only one way to kill off the
Martian and his mob. I'm taking it."

Suddenly Jim Holcomb understood. "No, Darl, no--you can't do it! Not
you! Let me go! I'm just a dumbhead. Let me go!"

"Thanks, Jimmy, but it's my place." Darl's voice was low, and very
calm. "I was in charge, and I lost the Dome. If I can save the boys on
the ship, and you two, it's the least I can do. Good-by, old man. Give
my regards to Earth."

Thomas' face was gray-white. The thick bandages that still swathed
him, Jim glimpsed them through the open neckpiece of the suit, gave
him the semblance of a mummy. The helmet clicked shut. Swallowing a
lump that rose in his throat, Jim pulled open the door. A wave of
Mercurians surged in, to be seared into nothingness by his