Historical information

Possibly part of a larger Heliograph - How to use: Hold the mirror a few inches in front of your left or right eye halfway between the sun and the target. The mirror is between your face and the sun. Look through the sighting aperture at your target (hole in center of mirror). While maintaining a view of your target through the sighting aperture turn and tilt the mirror until you see the "fireball" a virtual reflection of the sun. Turn and tilt the mirror to line up with the fireball and the image. Each time you move the "fireball" across the target you are sending a flash of light to the target. The target does not have to be in the center of the retroflected aimer. Used for morse code and other communication. WW1 WW2 and in Forestry.

Physical description

Round circular black compact hinged - When opened has mirror with hole in it on one side and black lid/cover on the other - Small lip on top cover.