e could get the
chance of a blow at them before he died!

He heard a door swing open--a door somewhere out on the prairie. Two
men sprang into sudden visibility and approached him. There was
nothing invisible about these men, though they had seemed to have
materialized out of nothing. They wore the same black, trimly fitting
uniform that Dick had seen in the White House. They were flesh and
blood human beings like themselves.

"I congratulate you upon your recovery, Captain Rennell," remarked one
of them with ironical politeness. "Also upon your shrewd coup.
Needless to say, it had no chance of success, but we were misinformed
as to the hour at which you might be expected. We thought it would
take the fools at Washington a little longer to puzzle out our
location--and then we did not put quite sufficient force into our
hurricane. Quite an artificial one, Captain."

Dick, glaring at them, said nothing, and the one who had spoken turned
to his companion, laughing, and said something in a foreign language
that he did not recognize.

"His Majesty the Emperor commands your presence, and that of this old
fool," said the first man. "Do not attempt to escape us. Death will be
instantaneous." He drew a glass rod from his pocket, the tip of which
glowed with a pale blue light.

* * * * *

Again he spoke to his companion, who moved apparently a few feet
distant out on the prairie. Suddenly Dick saw old Evans' chain
slacken: then Dick's slackened too. He understood that he was unbound,
though his wrists and ankles were still loosely fastened.

The second man took his station beside Luke Evans and motioned to him
to rise. The first man beckoned to Dick to do the same. The two
prisoners got upon their feet, trailing each a length of clanking
chain. Each of the two guards covered his captive with the glass rod
and motioned to him to precede him.

Choking with fury, Dick obeyed. He had taken a dozen steps with his
guard uttered a sharp command to halt, at the same time shouting some
word of command.

The edge of a door appeared, also seeming to materialize out of space.
It widened, and Dick realized that he was looking at the unpainted
inner side of a door whose outside was invisible. Beyond the door
appeared a flight of steps.

Dick passed through and descended them. He counted fifteen. He emerged
into a timbered underground passage, well lit with lamps, filled with
what seemed to be mercur