t it will be well to know at once. Come, my good fellow, and
what may be the one contingency I have overlooked?"

As he spoke Carthoris observed the servant closely for the first
time. He saw a man of giant stature and handsome, as are all those
of the race of Martian red men; but the fellow's lips were thin
and cruel, and across one cheek was the faint, white line of a
sword-cut from the right temple to the corner of the mouth.

"Come," urged the Prince of Helium. "Speak!"

The man hesitated. It was evident that he regretted the temerity
that had made him the centre of interested observation. But at
last, seeing no alternative, he spoke.

"It might be tampered with," he said, "by an enemy."

Carthoris drew a small key from his leathern pocket-pouch.

"Look at this," he said, handing it to the man. "If you know aught
of locks, you will know that the mechanism which this unlooses is
beyond the cunning of a picker of locks. It guards the vitals of
the instrument from crafty tampering. Without it an enemy must
half wreck the device to reach its heart, leaving his handiwork
apparent to the most casual observer."

The servant took the key, glanced at it shrewdly, and then as he
made to return it to Carthoris dropped it upon the marble flagging.
Turning to look for it he planted the sole of his sandal full upon
the glittering object. For an instant he bore all his weight upon
the foot that covered the key, then he stepped back and with an
exclamation as of pleasure that he had found it, stooped, recovered
it, and returned it to the Heliumite. Then he dropped back to his
station behind the nobles and was forgotten.

A moment later Carthoris had made his adieux to Thuvan Dihn and
his nobles, and with lights twinkling had risen into the star-shot
void of the Martian night.

CHAPTER II

SLAVERY

As the ruler of Ptarth, followed by his courtiers, descended from
the landing-stage above the palace, the servants dropped into their
places in the rear of their royal or noble masters, and behind the
others one lingered to the last. Then quickly stooping he snatched
the sandal from his right foot, slipping it into his pocket-pouch.

When the party had come to the lower levels, and the jeddak had
dispersed them by a sign, none noticed that the forward fellow who
had drawn so much attention to himself before the Prince of Helium
departed, was no longer among the other servants.

To whose retinue he had b