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.