ing of our
trouble."

"In what way?"

"Well, of course word will be sent on ahead about us, and every where
we go they'll be on the watch for us. They have our movements pretty
well covered."

"We won't make a descent until we get to Siberia," said Tom, "and I
guess there it will be so lonesome that we won't be troubled much."

"Perhaps," admitted the Russian, "but we will have to be on our guard.
Of course keeping up in the air will be an advantage but they may--"

He stopped suddenly and shrugged his shoulders.

"What were you going to say?" inquired Ned.

"Oh, it's just something that might happen, but it's too remote a
possibility to work about. We're leaving those fellows nicely behind,"
he added quickly, as though anxious to change the subject.

"Yes, at this rate we'll soon be out of France," observed Tom, as he
speeded the ship along still more. The young inventor wondered what Mr.
Petrofsky had been going to say, but soon after this, some of the
repaired machinery in the motor room needed adjusting, and the young
inventor was kept so busy that the matter passed from his mind.

The dynamo and magneto were doing much more efficient work since Tom
had put the new platinum in, and the Falcon was making better time than
ever before. They were flying at a moderate height, and could see
wondering men, women and children rush out from their houses, to gaze
aloft at the strange sight. Paris was now far behind, and that night
they were approaching the borders of Prussia, as Mr. Petrofsky informed
them, for he knew every part of Europe.

The route, as laid down by Tom and the Russian, would send the airship
skirting the southern coast of the Baltic sea, then north-west, to pass
to one side of St. Petersburg, and then, after getting far enough to
the north, so as to avoid the big cities, they would head due east for
Siberia.

"In that way I think we'll avoid any danger from the Russian police,"
remarked the exile.

For the next few days they flew steadily on at no remarkable speed, as
the extra effort used more gasolene than Tom cared to expend in the
motor. He realized that he would need all he had, and he did not want
to have to buy any more until he was homeward bound, for the purchase
of it would lead to questions, and might cause their detention.

Mr. Damon gave his friends good meals and they enjoyed their trip very
much, though naturally there was some anxiety about whether it would
have a successfu