The Weems Second-Setting watch was built by Longines to a system devised by US Navy Captain Philip Van Horn Weems, the navigation teacher of Charles Lindbergh, and the brand patented the system in 1935. Its purpose was to let a navigator synchronise a watch to the exact second with a radio time signal without stopping the movement: a rotating 60-second scale, first as a central disc and from 1935 also as a rotating bezel around central-seconds watches, could be turned until its zero lined up with the seconds hand. Early Weems watches from around 1928 were large 47 mm silver pieces with an enamel chapter ring, an inner silvered rotating disc and the calibre 18.69N. A steel Weems from 1937 with a rotating bezel measures 33.5 mm, with a second crown at 4 o’clock that locks the bezel. It matters as one of the first watches designed specifically for precise air navigation.

Weems had developed his navigation method in 1927, the year of Lindbergh’s transatlantic flight, and he turned to Longines, already a leading supplier of timing instruments for aviation. The watches were sold in the United States through Wittnauer, the brand’s American agent. Lindbergh later took the idea further in his own Hour Angle watch. Weems watches were made in several forms, from large 47 mm pilot pieces to more compact wristwatches, and some were delivered with special dials, including rare examples for the US Naval Academy bearing the crest “Ex Scientia Tridens”. In 2007, eighty years after the original model, the brand released a Longines Weems Second-Setting Watch with a 47.5 mm steel case, a self-winding movement and a silvered rotating central disc.

Collectors and dealers consider the Longines Weems among the most historically important aviation timepieces ever produced, valued for its link with Weems and Lindbergh and for the golden age of navigation it represents. Early examples are sought after at auction: a circa-1928 silver Weems with the calibre 18.69N sold at Uhren Muser in 2017 for 11,800 euros against an estimate of 9,000 to 13,000 euros. As with many military watches, collectors check for replaced crowns and restored bezels, which are common on surviving pieces. The original 1930s Weems is no longer produced; Longines has revisited the design with later re-editions such as the 2007 model.