er. By raising the top of the
periscope above the parapet the soldier can watch the foreground while
at the same time remaining completely concealed himself.

A more elaborate periscope for the control of artillery fire has a
collapsible tube which may be extended and elevated to a height of 75
feet.

=1208. Sniperscope.= This is a combination of the periscope and rifle
by means of which a soldier can aim and fire his piece at an object
without exposing himself above the parapet.

=1209. Aids to firing.= Rifles laid in notched boards placed in the
parapet may be sighted and prepared for night firing, or a wire
stretched just outside of the loophole on which the barrel of the
rifle can rest when in the proper firing position to cover certain
points, enables the soldier to fire effectively at night when it is
too dark to aim.

=1210. Mining.= Military mining consists of digging communications and
chambers underground and placing therein charges of explosives and
firing such charges. Mining is slow and restricted in its application
and therefore this method of attack is used against very strong points
of the enemy's line,--a salient, a building, or other point,--held in
great force. The aim in mine warfare is to make a sudden breach in the
enemy's trench, destroy the flanking supports which could be used to
stop this breach and then to take the trench by assault and organize
it for defense before the enemy's forces, disorganized from the
explosion, can recover.

Sometimes mines are placed in front of the trenches and exploded
electrically when the enemy reaches them in attempting an assault.

=1211. Countermining.= The enemy, when mining operations are
suspected, runs out tunnels to meet the opposing mine. Sometimes
listening galleries are driven underground and men posted to detect
the sound of mining operations. Once the direction of the opposing
tunnel is discovered a charge of explosive is laid across its approach
and fired at a moment when it will cause the most damage.

FOOTNOTES:

[14] To those desiring to go into the subject of trench warfare in
detail, the author would recommend "Trench Warfare," by himself.
George Banta Publishing Co., Menasha, Wis.; $1.25.

CHAPTER XIII

MARCHES

(Based on Infantry Drill Regulations and Field Service Regulations)

=1212. Marching principal occupation of troops in campaign.= Marching
constitutes the principal occupation of troops in campaign and is one