martest detectives in the French service, and the only two men who
ever guessed the true nature of this house. They are buried under the
floor on which you are standing at this moment."

The words were spoken with a cruel inflexible coldness, which struck
Arnold like a blast of frozen air. He shivered, and was about to
reply when Colston caught him by the arm again, and said hurriedly--

"H'st! We are going in. Remember what I said, and don't speak again
till some one asks you to do so."

As he spoke a door opened in the wall of the dark chamber in which
they had been standing for the last few minutes, and a flood of soft
light flowed in upon their dazzled eyes. At the same moment a man's
voice said from the room beyond in Russian--

"Who stands there?"

"Maurice Colston and the Master of the Air," replied Colston in the
same language.

"You are welcome," was the reply, and then Colston, taking Arnold by
the arm, led him into the room.

CHAPTER V.

THE INNER CIRCLE.

As soon as Arnold's eyes got accustomed to the light, he saw that he
was in a large, lofty room with panelled walls adorned with a number
of fine paintings. As he looked at these his gaze was fascinated by
them, even more than by the strange company which was assembled round
the long table that occupied the middle of the room.

Though they were all manifestly the products of the highest form of
art, their subjects were dreary and repulsive beyond description.
There was a horrible realism about them which reminded him
irresistibly of the awful collection of pictorial horrors in the
Musee Wiertz, in Brussels--those works of the brilliant but unhappy
genius who was driven into insanity by the sheer exuberance of his
own morbid imagination.

Here was a long line of men and women in chains staggering across a
wilderness of snow that melted away into the horizon without a break.
Beside them rode Cossacks armed with long whips that they used on men
and women alike when their fainting limbs gave way beneath them, and
they were like to fall by the wayside to seek the welcome rest that
only death could give them.

There was a picture of a woman naked to the waist, and tied up to a
triangle in a prison yard, being flogged by a soldier with willow
wands, while a group of officers stood by, apparently greatly
interested in the performance. Another painting showed a poor wretch
being knouted to death in the market-place of a Russian town, and yet