braced with boards and cross pieces of
wood, such as is often used when a sewer is dug through the streets,
and again wicker-work, or jute bagging, might be used to hold the
earth firm.

Below the top of the trenches, in certain places, were projections.
These were firing steps, and the men stepped up on these to aim their
rifles at the enemy. In certain other places were set up improvised
periscopes, so that an officer could look "over the top," and, by a
series of reflecting mirrors, observe what was going on in the enemy's
country.

Again, at other places in the trenches, light artillery, such as
machine guns and grenade throwers were set up. Here and there were
little stoves to warm the food brought up whenever a relief party
could get through the rain of shells. In some places heavy concrete or
wooden dugouts were constructed, well under ground, though the Germans
did more of this than the Allies, the Hun trenches being very
elaborate at times.

And it was to these trenches that Ned, Bob and Jerry, with their
comrades, were led. There they would remain on duty for a specified
time differing under varying conditions, or until an attack was either
made by them or by the enemy. After that, in case the enemy were
successful, trenches farther in the rear must be occupied. But in the
event of the German attack being repulsed, and a counter-attack
carrying the Allies forward, advanced trenches--possibly those
deserted by the Huns--would be used.

"Forward!" came the command, and the three Motor Boys advanced. They
did not march long in open formation. To do this would be dangerous,
within range of the German guns as they were, and, too, they might be
seen by a Hun observer in an aeroplane. So, in a little while the
advancing squad, of which Ned, Bob and Jerry formed a part, found
itself in a communicating trench. This was a ditch dug at right-angles
to the front-line trenches, and through this the relief passed, and
food and ammunition were brought up.

The communicating trench zig-zagged, as did the front-line ones, to
provide greater safety, and the boys finally gave up trying to guess
in which direction they were going. All they could see was the sky
above their heads.

Suddenly, however, the trench widened, and they saw another crossing
it. At this point, too, there was what seemed to be a rough door, made
of planks nailed together.

"This is your dugout," said the leading officer, indicating that Ned,
Bob