. And they drove on to the
attack, to strike at an enemy that shot instantly into the sky leaving
crashing destruction about the torn dead.

"Now!" said Cyrus Thurston aloud.

* * * * *

The big bulbs were back. They floated easily in the air, a plume of
vapor billowing beneath. They were ranging to the four corners of a
great square.

One plane only was left, coming in from the south, a lone straggler,
late for the fray. One plane! Thurston's shoulders sagged heavily. All
they had left! It went swiftly overhead.... It was fast--fast. Thurston
suddenly knew. It was Riley in that plane.

"Go back, you fool!"--he was screaming at the top of his
voice--"Back--back--you poor, damned, decent Irishman!"

Tears were streaming down his face. "His buddies," Riley had said. And
this was Riley, driving swiftly in, alone, to avenge them....

He saw dimly as the swift plane sped over the first bulb, on and over
the second. The soft roar of gas from the machines drowned the sound of
his engine. The plane passed them in silence to bank sharply toward the
third corner of the forming square.

He was looking them over, Thurston thought. And the damn beasts
disregarded so contemptible an opponent. He could still leave. "For
God's sake, Riley, beat it--escape!"

Thurston's mind was solely on the fate of the lone voyager--until the
impossible was borne in upon him.

The square was disrupted. Three great bulbs were now drifting. The wind
was carrying them out toward the bay. They were coming down in a long,
smooth descent. The plane shot like a winged rocket at the fourth great,
shining ball. To the watcher, aghast with sudden hope, it seemed barely
to crawl.

"The ray! The ray...." Thurston saw as if straining eyes had pierced
through the distance to see the invisible. He saw from below the swift
plane, the streaming, intangible ray. That was why Riley had flown
closely past and above them--the ray poured from below. His throat was
choking him, strangling....

* * * * *

The last enemy took alarm. Had it seen the slow sinking of its
companions, failed to hear them in reply to his mental call? The shining
pear shape shot violently upward; the attacking plane rolled to a
vertical bank as it missed the threatening clouds of exhaust. "What do
you know about dog-fights?" And Riley had grinned ... Riley belonged!

The bulb swelled before Thurston's eyes in its swift d