I have in for service a Longines Deck Watch Chronometer that basically is a robust pocket watch movement mounted in a gimballed frame with double wood case in the manner of a ship's chronometer. The movement is approximately 36 hour run time and is stem-wind lever set; you have to unscrew the bezel to access the lever. Photos follow below. The dial photo shows a silvered dial with "Longines Chrono Meter", Arabic numbers with arabic seconds bit, deep blued hands. The back plate has the following info: >Adjusted to three 3 positions >Twentyone 21 JEWELS >LONGINES Watch Co. Swiss >1874897 The rate adjustment is interesting, with a kind of snail to provide gradual rate increase or decrease, with a pointer of the snail on a graduated scale. The last photo is with the lever set extended. Questions: * Approximately when was this made? * Is there a Longines serial number database or table from which to obtain a date, movement size, etc? * The lever set is not at all easy to use to obtain accurate time set, the minute hand tends to jump when the lever is pushed in. Any suggestions for improvement? * At what level did Longines participate in ship's chronometer production? Were they a significant producer? Any other info will be very much appreciated. Photos added of the carrying case and chronometer case, movement in gimbal.