Forged iron, 4 5/8” height, octagonal section with flared base and touch hole with chisel raised ignition pan. 1 1/16” bore. Used both for navigation and aiming cannon from a moving ship. A series of these were fired from shore at timed intervals so ships at sea could measure the difference in the intervals between the visual flash and the sound of the reports, and calculate their positions and speed. The perfection of navigation instruments rendered them obsolete and thus, most were scrapped.