hinery ran
well.

Cautiously they ate and drank, feeling their strength come back to
them, and then they removed the traces of their terrible imprisonment,
and set about in ease and comfort, talking of what they had suffered.

Onward sped the aeroplane, onward through the night, and then Tom,
having set the automatic steering gear, all fell into heavy slumbers
that lasted until far into the next day.

When the young inventor awoke he looked below and could see
nothing--nothing but a sea of mist.

"What's this?" he cried. "Are we above the clouds, or in a fog over
some inland sea?"

He was quite worried, until Ivan Petrofsky informed him that they were
in the midst of a dense fog, which was common over that part of Siberia.

"But where are we?" asked Ned.

"About over the province of Irtutsk," was the answer. "We are heading
north," he went on, as he looked at the compass, "and I think about
right to land somewhere near where my brother is confined in the
sulphur mine."

"That's so; we've got to drop," said Tom. "I must get the gas pipe
repaired. I wish we could see over what soft of a place we were so as
to know whether it would be safe to land. I wish the mist would clear
away."

It did, about noon, and they noted that they were over a desolate
stretch of country, in which it would be safe to make a landing.

Bringing the aeroplane down on as smooth a spot as he could pick out,
Tom and Ned were soon at work clearing out the clogged pipe of the gas
generator. They had to take it out in the open air, as the fumes were
unpleasant, and it was while working over it that they saw a shadow
thrown on the ground in front of them. Startled they looked up, to see
a burly Russian staring at them.

The sudden appearance of a man in that lonely spot, his calm regard of
the lads, his stealthy approach, which had made it possible for him to
be almost upon them before they were aware of his presence, all this
made them suspicious of danger. Tom gave a quick glance about, however,
and saw no others--no Cossack soldiers, and as he looked a second time
at the man he noted that he was poorly dressed, that his shoes were
ragged, his whole appearance denoting that he had traveled far, and was
weary and ill.

"What do you make of this, Ned?" asked Tom, in a low voice.

"I don't know what to make of it. He can't be an officer, in that rig,
and he has no one with him. I guess we haven't anything to be afraid
of. I'm going to