Made in Massachusetts by the Chelsea Company whose specialty clocks have been used in an impressive variety of scientific recording instruments for well over a 100 years. Donald MacMillan used a number of Chelsea clocks to record the magnetism at the North Pole, and Admiral Byrd used their clocks for recording temperature, pressure and humidity on his South Pole expedition. Seventeen Presidents, from Woodrow Wilson to Bill Clinton, have purchased a Chelsea clock for personal use or as a gift for visiting dignitaries. The shipstrike clock is one of their most popular editions. Unlike other clocks, it chimes the time based upon the workday routine of a ship's crew. This bell code dates back hundreds of years, when ships at sea required a crew on constant watch, twenty-four hours day. For duty assignments, the day was broken up into six watches of four hours each. The watch officer would strike the ships bell at half hour intervals: one bell at 12:30, two bells at 1:00, three bells at 1:30 and so on; eight bells marked the end of the watch at 4, 8 and 12 o'clock. The clock sits on a solid mahogany base. Five jewel, German movement. Key wound. Forged brass with a six-inch, aluminum dial. Hinged bezel to facilitate winding. Clock: 7 1/2" Diam. x 3 1/2" D. Base: 4" W. (13 lbs.)