-"

* * * * *

The dark haired aviator's words were drowned out in a deafening,
hissing roar that burst from the great retortii's throat, and his
heart gave a great convulsive leap at the sight. Was this an
accident--or treachery? An accident of course. Somehow he could not
bring himself to think that Altorius would break his pledged word.
Projected in a shimmering white arm the scalding death vapor shot
across the staircase, its hot breath licking the faces of the startled
and angry Americans, and quickly forcing them to turn and run
downwards to avoid being scalded.

"What the devil are these idiots trying to do?" gasped Nelson,
anxiously eyeing the red-crested warriors who, peering down through
the blue lenses of their helmets, watched the khaki-clad aviators but
made no effort to realign their retortii. "Hero Giles'll skin those
fools alive if he hears of this. Guess we'd better wait a minute:
they'll soon shut off the steam."

Shielding his face from the steam clouds that obliterated all view of
the staircase above, Alden stood watching the billowing steam clouds
in silent awe.

"Terrible, aren't they, Vic?" he remarked. "I've never seen those big
fellows in action. They make the portable variety look like water
pistols."

* * * * *

As the steam barrier showed no signs of abating, an uneasy gleam crept
into Nelson's dark eye, and with jaw grimly set, he cocked the
Winchester and turned with the intention of lodging a complaint at the
next station below; but, to his utter dismay, he beheld bronze armored
figures on the next platform now training their long-muzzled steam gun
across the stair. Even as he sprang back, the deadly white vapor
hissed forth from the second retortii, completely barring further
retreat down the stair. Like an icy flood the chill of impending doom
invaded Nelson's soul. This was no accidental discharge, for with the
slightest change of direction in the deflection of either retortii,
death would descend upon him and his companion.

Swiftly speech became impossible, as the roar of the huge retortii was
deafening; the two were lost in the heart of an opaque cloud which
completely blotted out the copper-hued Atlantean sky. Hot blood surged
into Nelson's head while he became aware of ghostly and stealthy
figures advancing through the shimmering billows of vapor. Up, up,
they came, like dream men, their eyes weird and unreal.