removes the earth in sandbags.

Progress under such circumstances must be slow, but it is made slower by
the necessity of running galleries at right angles to the main tunnel
from time to time in an effort to locate the enemy.

Here men are posted, while all work is for a time stopped, to listen for
the first sounds of the enemy's sappers--the thud-thud of the picks or
the "cough" of the man whose lungs seek this relief in the stuffy air of
the cramped tunnel.

If the enemy is not found, progress is continued forward from both ends
of the cross-gallery and the game goes merrily on.

About this stage the mining officer will, if you happen to be holding
the trench under which he is grovelling, wax eloquent over a crumpled
sheet of tracing linen that he presents to your view as a diagram of the
workings. It looks like nothing so much as a drawing of the kith and kin
of an old and prolific family; but you dare not tell him that, or he
will be your enemy for life.

Instead you should say, "Ahem!" and "Oh, yes; how clever!"--then he will
ask you for only ten instead of twelve men on the night's working party.

But once the enemy is located you begin to regard him more seriously,
for on his skill depends the life of every man in the trench above, and
a false change in direction may mean missing the enemy's tunnel
altogether.

Sometimes, but not often, the mining is so quietly done that the first
sign of the enemy is the sudden collapse of the wall of earth between
the two galleries, leaving the rival workers face to face!

At other times, and this is a normal occurrence, the enemy are heard to
one side or the other, and a small charge of powder is laid and his
gallery is blown in, crushing his workers to death, or perhaps merely
burying them to perish miserably by suffocation.

To prevent this occurring men are kept in the ends of all the passages
listening for the tap-tap of the picks that spells danger!

If the picks are heard for a while and then stop, there are anxious
moments, for it may mean that the enemy has located our workers and
decided to blow first and wreck our galleries, or it may mean the
explosive is already in place and ready for firing, or perhaps only a
change in the direction of the enemy's tunnel.

The situation is not a pleasant one for either the men in the trench
above or the sappers in the galleries below, and on the mining officer's
decision much depends.

It was while we were breakfas