d the trigger. There was a whoosh of fire and a flare from
the launcher's nose. A minute spark winged into the darkness toward the
spot, still many miles away, where the strange ship hung.

They watched with bated breath. Suddenly there was a flash of light from
the other ship--a vivid lightning bolt which leaped out and flared up
briefly in space. Then darkness again.

"They fired a burst of energy at us. It hit the rocket shell instead,"
said Haines. "Well, now we know. They use bolts of pure
energy--something like the one they fired at Boulton."

He fitted another shell into the launcher, and fired again. Again a
spark winged its way, and the bolt of energy burst out to detonate the
shell. Burl whistled. "How did they spot it so fast?" he asked.

"I don't think they did. They're firing at us--the rocket shell only
happened to be between," snapped Haines.

"Ferrati," he called into his mike, "fire a shrapnel shell at them when
I say the word. Advise me when ready!"

Ferrati's voice snapped back. "Right you are, sir. Here it is now, one
minute--okay, on target!"

While Ferrati and Boulton were readying their shot from the lower cargo
port near the tail of the ship, Haines and Burl had been fitting the
largest of their shells into their own launcher. They aimed it
carefully at the front-most sphere of the enemy.

"Ferrati, fire!" cried Haines, and then slowly counted to five and
pressed the stud of his own launcher.

There was a momentary flicker as Ferrati's rocket shell raced forth
below. Then, after a definite time lapse, the exhaust of Haines' heavy
shell appeared.

"The shrapnel shell is segmented and doesn't have a proximity guide,"
Haines explained. "As soon as it's on its way, the nose comes apart into
a dozen small shells, each with a standard explosive charge. The shell
we used has an atomic bomb warhead and is on proximity guide. It'll
chase that ship to the ends of the system if they don't blast it first."

He paused. There was another bolt of raw energy from the dumbbell-shaped
craft, and this time a series of flares in the space between--the
shrapnel charges had been touched off. Burl held his breath.

"I figure it takes them a while to recharge their gun," said Haines.
"Our own blockbuster should get there before they fire again."

Then suddenly there came a sharper flare of brilliant light. For an
instant Burl was blinded by the glare. When he recovered, he peered
avidly through the telesc