On a dueling ground between the rival armies Nelson, armed with his
Winchester rifle, sallies out to battle with the enemy, who, on their
side, are armed with retortii--curious weapons hurling live
steam--fungus bombs, swords and lances.

The tricky Jarmuthians, however, mount their men on a diplodocus, a
huge dinosaur some eighty-seven feet in length. All seems lost; but by
blinding the colossal creature, Nelson destroys its usefulness, and
one by one kills the six Jarmuthians.

Stung with rage, the enemy disregard the terms of the contest and
attack with their whole army. They are, however, defeated, and the
conquered Jarmuthians sullenly turn over Alden and the captive
maidens; though Altara still remains in their possession.

After making much of the Americans, Altorius reluctantly allows his
preservers to depart for their plane--unconscious that the priestly
party is planning rebellion against his authority because he did not
insist on Altara's return.

CHAPTER VII

"That's one of the fixed retortiis I was speaking about," remarked
Victor Nelson as he paused to point out a tapering brass tube which
was mounted on a platform above the long staircase up which he and
Alden were toiling. "It's a big brute: see how small the gunners look
beside it? These steam guns are wonderful things."

The younger aviator sighed. "I've had enough of miracles," he said
wiping his flushed features and hitching a small pack higher on his
leather-clad shoulders. "All I want to do is to lay my weary eyes on
the plane again. What with these ghastly allosauri, diplodocuses and
other monsters, I'm damn well fed up with this place."

Nelson settled his Winchester rifle more comfortably into the hollow
of his arm. "Correct. So am I. But we can't say Altorius didn't do
right by our Nell. Good Lord, what a triumph he gave us!" The dark
pilot's smile flashed from beneath his neat, close-clipped black
mustache. "Wait till Cartier gets a peep at those diamonds he gave
us."

Panting, the two halted by mutual consent. "Ever see so many stairs?"
grunted Nelson. "Three more flights and we'll be into the tunnel; ah,
there's the opening. I only hope these blighters haven't hurt the
plane."

Before resuming the climb Nelson shifted his rifle, idly regarding the
armored gunners just above; then suddenly he stiffened his wiry body
with a sharp cry. "Look out, Dick! What the devil? Those damn fools
ahead are swinging the retortii across our-