A mid-20th century marine chronometer, the eight day chain fusee movement with maintaining power and bimetallic balance, the backplate signed 'Made by Thomas Mercer St. Albans England', the 5-inch silvered dial with black Roman hour numerals and subsidiary state of wind and seconds dials, inscribed 'Kelvin & Wilfred O. White Co. Boston & New York', housed in a lacquered brass bowl hung in gimbals, the brass bound walnut two tier case with glazed hinged lid, applied with 'Southwest Instrument Company, San Pedro, California' labels to front and case interior, height 20.9cm (lacking top tier of case), together with a 'Mercer Chronometers' book by Tony Mercer.