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Lot Essay
According to the Archives of Montres Longines Francillon SA, the present watch is part of a small pre-series of such aviators watches made as of January 1931, fitted with Weems' second setting system. The rotating outer ring would allow the precise setting of both seconds and time. For test purposes, early examples of the model, such as this watch, were fitted with a sliding lever in the right band, a system which however never went beyond the experimental status. The succeeding series featured a central disk, calibrated for the seconds, which could be rotated while depressing a button in the band and simultaneously turning the crown, hence allowing the synchronized setting of time and seconds.
Another interesting feature is the movement, calibre 18.69 N as used in subsequent series. However, the present watch is lacking, other than the Longines name and the serial number, all other designations which can normally be found. Interestingly, close inspection reveals that Longines' watchmakers finely engraved these details at the positions where future regular production pieces would have them. Given the fragile nature of these words, it must be assumed that they were executed with the point of a needle. They read 15 fifteen jewels, unadjusted, Swiss, LXW Watch Co.
The precise measurement of time has been vital to the progress of navigation throughout history. With the 1930s started a period of revolutionary changes in navigation and foremost among those responsible for some of the improvements was Captain Philip Van Horn Weems, U.S. Navy, who also trained the famous aviator Charles A. Lindbergh.
One of Weems' inventions was the Second Setting Watch, designed to help aviators plot their courses more accurately. At sea, celestial sights had to be taken with the help of a hack watch, which was set to the ship's chronometer. It was difficult, however, to set the watch exactly, meaning that it differed slightly from the chronometer, which in turn differed from Greenwich Mean Time.
Weems deducted that the difficulty in setting the watch came from the fact that, at the time, it was almost impossible to set the second hand exactly. However, as the second hand could not be set to match the dial perfectly, the solution was to make the dial movable, so that the dial and the second hand could be synchronized at the right time.
Another characteristic of the "Weems" watch is the large ball-sized winding crown, allowing the rewinding of the movement while wearing gloves.
Later examples of the "Hour Angle Watch" are illustrated in Longines Watches by John Goldberger, pp. 78 & 79.
Another interesting feature is the movement, calibre 18.69 N as used in subsequent series. However, the present watch is lacking, other than the Longines name and the serial number, all other designations which can normally be found. Interestingly, close inspection reveals that Longines' watchmakers finely engraved these details at the positions where future regular production pieces would have them. Given the fragile nature of these words, it must be assumed that they were executed with the point of a needle. They read 15 fifteen jewels, unadjusted, Swiss, LXW Watch Co.
The precise measurement of time has been vital to the progress of navigation throughout history. With the 1930s started a period of revolutionary changes in navigation and foremost among those responsible for some of the improvements was Captain Philip Van Horn Weems, U.S. Navy, who also trained the famous aviator Charles A. Lindbergh.
One of Weems' inventions was the Second Setting Watch, designed to help aviators plot their courses more accurately. At sea, celestial sights had to be taken with the help of a hack watch, which was set to the ship's chronometer. It was difficult, however, to set the watch exactly, meaning that it differed slightly from the chronometer, which in turn differed from Greenwich Mean Time.
Weems deducted that the difficulty in setting the watch came from the fact that, at the time, it was almost impossible to set the second hand exactly. However, as the second hand could not be set to match the dial perfectly, the solution was to make the dial movable, so that the dial and the second hand could be synchronized at the right time.
Another characteristic of the "Weems" watch is the large ball-sized winding crown, allowing the rewinding of the movement while wearing gloves.
Later examples of the "Hour Angle Watch" are illustrated in Longines Watches by John Goldberger, pp. 78 & 79.