*

A slight smile played over Hero Giles' thin lips as he watched the
amazed aviator.

"The splendor of our country must indeed astound thee," he observed,
"having come from the dreary fastness of the outer Ice World. But
come; we are now to pass the great retortii guarding the entrance into
the valley."

Nelson's eyes turned again to the weapons that so oddly resembled
field guns. He examined them closely, inspecting them narrowly for the
differences he knew must exist between them and the artillery that had
thundered during the War of the Nations.

The chief difference lay in the mounting of these starkly beautiful
weapons. They seemed to be fixed on a movable pivot set into the coal
black rock itself. Like modern artillery, these curious pieces of
ordnance bore a bronze shield to protect their crews, through which
projected the long and very narrow barrels of the guns. Grouped like
cannoneers about their piece stood various red-crested Atlantean
artillerymen. At a glance Nelson recognized the difference in their
equipment from that of the spearmen behind them. These former bore no
shields, no swords or bombs, but wore that same kind of leather
body-armor which graced the powerful limbs of Hero Giles. Their
helmets, too, were different: only the dolphin crest with a tuft of
red feathers spouting from it bore any resemblance to those of the
infantry, and, moreover, the artillerymen's eyes were shielded by
goggles with thick blue lenses.

* * * * *

As the Hero approached, officers among them saluted, then sank on one
knee with head humbly bent.

"Rather odd looking guns," commented Nelson. "I'm not much of an
artilleryman, but I'm wondering how you take up the recoil?"

The Atlantean's laugh, which always reminded his guest of the purr of
a tiger, rang out. "Why, marry, good sir, there is no recoil! These
guns do not use that powder which Sir Henry, founder of our line, did
speak of. Thou wouldst see one fired?"

His curiosity immeasurably piqued, Nelson nodded, whereupon the
Atlantean wheeled about and barked a brief command. With truly
Prussian precision, the artillerymen sprang to their posts, some to a
series of levers which sprouted from the rock platform without any
apparent connection, and some to wheels and gauges of varying size
that clustered in bewildering intricacy about the breech of the great
brass gun.

"Markest thou that tree yonder, on the ledge of the v