Trench-mounted viewing device with a screen, through which Carl watches for the opening explosions.
Carl used a periscope with a screen to observe No-Man's Land from the safety of The Trench. When Louis messaged that he had the target in sight, Carl turned back to the periscope screen and waited for the first explosion.
The device gave him little. Roiling clouds filled No-Man's Land, hugging the ground, and a low ceiling of black clouds hung overhead, so he could see nothing of the detonations — he could only hear them and feel them through the ground. He kept peering through it while questioning Donut about her promised prize, and continued watching as four explosions walked across the enemy lines.
A trench-mounted periscope feeding a viewing screen at eye level for the operator below the parapet.
Carl's observation post for the assault, largely defeated by the fog and cloud cover.