a raging furnace. Together they all ran
from the building, and none too soon; for suddenly the roof collapsed, a
tremendous burst of crackling flames and sheaved sparks leaped high
above the tree-tops, and the walls came crashing in.

In the welter of incandescence, where now only the stone chimney
stood--and this, too, was already cracking and swaying--Brevard had
found his tomb, together with the two Air Trust spies. All that
pleasant, necessary place was now a mass of white-hot ruin; all those
books and pictures now had turned to ash.

The five remaining comrades paused by the hangar, and looked mournfully
back at the still-leaping volcano of destruction.

"Poor Brevard! Poor old chap!" said Craig. He peered at the women.
Neither one was crying--they were not that type--but both were pale.

"I don't feel that way," said Gabriel. "Brevard is not to be pitied.
He's to be envied! He died in the noblest war we can conceive--the war
for the human race! And his last act was to take part in a battle that
stamped out two vipers, Air Trust spies, who would have joyed to burn us
all alive!"

[Illustration: The spy's body burst into a sheaf of fire.]

"Thank God, I got the Hell-hounds!" muttered Craig. "Two less of Slade's
infamous army, anyhow." Though Gabriel knew it not, the first one to
fall was the same who had battled with him in the trap at Rochester, the
same who had trailed him when he, Gabriel, had left the Federal pen. So
one score, at least, was settled.

"They're gone, anyhow," said Gabriel, "and five of us still live--and
I've still got the plans and all. Moreover, the monoplanes are safe. The
quicker we get away from here, now, the better. Away, and to our last
remaining refuge near Port Colborne, on the shores of Lake Erie. Other
Air Trust forces may be here, before morning. We must get away!"

A frightful shock awaited them when, entering the hangar--eager now to
escape at once from the scene of the tragedy--they beheld their
aeroplanes.

By the ruddy light which shone in through the wide doors, from the fire,
they saw long strips and tatters of canvas hanging from the 'planes.

"Smashed! Broken! Wrecked!" cried Gabriel, starting back aghast.

The others stared. Only too true; the monoplanes were practically
destroyed. Not only had the spies, before attacking the refuge, slashed
the 'planes to rags, but they had also partly dismantled the motors.
Bits of machinery lay scattered on the floor of the