nd when they came near to the stretch of road that
Ivan had told them would mark the crisis of the trip, both boys were in
good condition for the test. They slowed down at the sound of an
engine's whistle, the first nearby noise that had come to their ears
since they had left the parsonage. It startled them tremendously at
first, but then they remembered Ivan's warning.

"There is one place where, for about four miles, the road runs very
close to the railway," he had said. "The Germans will have patrols all
along the railway line, but there is no reason why they should pay any
attention to you. Be watchful--that is the vital thing. And especially
so when you begin to descend a long hill. At the bottom of that hill the
railway crosses your road, and that culvert will be watched with
especial care. After that you will find the way clear, for our nearest
outposts should not be more than a mile or so beyond the railway there.
We would have seized the line before, except that until we had
straightened our front in that quarter it would have been useless to do
it."

The whistle that they heard warned them that they were getting near to
this dangerous stretch of road, and in a few moments the sight of a
train, sparks flying from the smokestack of the engine, gave them visual
proof as well. Then for a time they ran along parallel with the tracks.
Fires were burning along the railway at intervals of about a hundred and
fifty yards, and at times, in the firelight, they could see a dark
figure moving slowly.

"Heaven knows what this bugle means!" said Fred, as they drew into line
with the tracks. "But if we sound it they may make up their minds that
we're all right--and I'm not anxious for them to get curious about us."

So he sounded the bugle from time to time. They aroused no curiosity.
Plainly these sentries thought there was nothing strange about the
passage of a military automobile, nor, in fact, was there. It was not
likely that they would know enough of the general disposition of the
German army to speculate as to what officers might be doing hereabout.

"Here we are! We're beginning to dip," said Boris, after a time. "The
culvert Ivan spoke of must be at the bottom of this hill. The road gets
away from the railway again after that, and when we have passed there we
ought to be all right."

"There's just one thing," said Fred, with a frown. "They must know just
as well as Ivan that the Russian outposts lie not far bey