of course," said Frank. "They can throw them on the
trenches--and they're good to guard against aeroplanes and dirigibles,
too. At night, you see, there'd be a chance for aeroplanes to fly very
low and do a lot of damage."

"Can't they hear the engines from the ground?"

"Not always. They have mufflers on a good many aeroplane motors now, so
that they don't make any more noise than a quiet automobile."

"I didn't know that. Well, there's one good thing about the
searchlights. We know which way to go. Come on."

"All right. The more I think of it, the better it is not to be on the
roads. Here in the fields we're a lot less likely to run into stray
parties. And I'd just about as soon meet Germans as allies. If they're
retreating and having trouble, they might hold us up as long as the
Germans would. They wouldn't believe we really had despatches."

For a time they made good, steady progress. The roar of artillery fire
in front of them had been resumed, and now it filled the air, proving
that they were much closer to the battle. The great waves of sound beat
against their ears, making their heads swim at first, but gradually they
grew used to it, and could hear other and more trivial sounds--the
chirping of night insects and the occasional hooting of owls.

"I don't hear the rifle fire," said Henri, after a time. "Only once in a
while, that is. Why is that, I wonder? Are the big guns drowning it?"

"No. Because if that were the reason, we wouldn't hear it at all. I
think they don't do that at night. It's just a case of trying to find
the places where the enemy's troops are massed, and keeping up a steady
fire of shells to drive them out. Maybe the searchlights help. They've
been fighting all day, you know, and even soldiers have to have some
rest. They have to eat and sleep or they can't keep up the work."

They crossed more than one road, but stuck to the fields, travelling in
a straight line as nearly as they could figure their course. When they
had decided to join the Boy Scouts, both had studied the stars, since a
knowledge of the heavens is one of the most important things about
scouting, and they found what they had learned very valuable now. Thus
they could keep their bearings, though owing to their desertion of the
roads, Henri confessed that he had very little idea of where they were.

"Along the roads one has landmarks," he said. "I have gone all through
here, over and over again. My father used to drive