Weems Watch

In 1927 Philip Van Horn Weems, a U.S. Navy officer, devised a watch with a settable second hand that could be easily corrected to the second using radio time signals. That made it more useful for air navigation than even precision maritime chronometers and was the beginning of the aviator's "hack" watch. Longines produced a number of 'Weems Watch' variantions in 1920s-1940s (plus later limited editions, incl. present-day Heritage series).