This is a rare and highly collectable watch, an all original Wittnauer (part of Longines) Weems gentlemans' aviator's navigation watch dating to the early 1940's. It is in lovely original un-restored condition, still presenting very well after nearly 80 years. This timepiece was invented by Commander PVH Weems, an American naval officer who specialised in navigation and taught Charles Lindbergh who undertook the first solo flight across the Atlantic from New York to Paris in 1927. The Weems watch was designed as an aviator's celestial navigational aid. Whilst ships used chronometers for this purpose, their use in small aircraft was not practical. The use of wristwatches for navigation, which were not generally capable of chronometer accuracy, coupled with the high speeds at which aircraft flew compared to ships, presented a challenging problem. Small errors in time accuracy caused large errors in calculating position. Many pioneering pilots attempting long distance flights died as a result of navigation errors. The Weems watch was designed to enable it to be synchronised to a known accurate time signal to the second as a means of calculating longitudinal position when airborne. Whereas today time synchronisation can be achieved with a watch possessing a hacking mechanism which stops it from running when the crown is pulled out, this feature was not generally available in the late 1930's. Therefore Weems solved the problem by using a rotating bezel on the watch which has segments numbered 0 - 60. The scale is turned with the second hand until the external time signal marks the minute, thus enabling the time difference between the Weems watch and the time signal to be established accurately. If you do a Google search for the Weems watch you can find a more detailed description about how the it works. Longines still manufacture and sell the Longines Weems watch today, now costing £2930.
Dial: factory original in great condition, showing gentle patina. It is finished in two tone satin silver with hours marked by Arabic numerals. The dial is signed "Wittnauer Swiss".
Case: made of 10 carat rolled gold, measuring approximately 35 mm from lug to lug and 26 mm across, excluding the original crowns. The inside of the case is signed "Wittnauer" and hallmarked as 10K Rolled Gold Plate. The crown at 3 o'clock is used to wind and set the watch. The crown above it unscrews to enable the bezel to be turned for synchronisation and then screwed back in to lock it into position. The case presents well, showing some inevitable small scratches, dings and a little brassing.
Movement: signed "Wittnauer" with 16 jewels, running and keeping time.
Strap: fitted with a new generic brown leather lizard grain strap, which attached to the watch measures approximately 204 mm from buckle tip to last hole.