Marine chronometer: very rare Thomas Mercer Chronometer, no 13662 1910-1920. Approximately. 20 × 20 × 20cm, 2-piece mahogany and brass case with clip-on typical glass, rare Spring-loaded chronometer movement with 8-day power reserve, cylindrical spiral, silver dial with signature and number, beautiful steel hands, in good working condition, Box including key. The marine chronometer is extremely rare. This is the same Chronometer from this period by Thomas Mercer, known to have been delivered to Rolex watch No. 13662 dated 1915.