7" x 3 1/4" As found. Provenance: The Edward Herrmann Estate, Salisbury Connecticut.
Smiths Astral clock, 1912-1946, has the two 3 minute red sectors (in the 3 and 9 position). These were the silent periods for maintaining a listening watch on the Radiotelegraphy Distress Frequency. Clock was located in the radio room of a military ship.
