Watches made by Lecomber have “Decimal Chronograph Registered 13 Sept 1875” on the dial, and usually have Lecomber's name on the movement and his JL incuse sponsor's mark on a hallmarked case. Lecomber claimed as part of his design an escape wheel pinion with 6 teeth working with a fourth wheel pinion with 60 teeth. This dial was to be used with a movement having an 18,000 vph train, which ticks five times per second or 300 times per minute. On 13 Sept 1875, John Lecomber, a wholesale watch manufacturer of Liverpool, registered under the Merchandise Marks Act (1862) a “Decimal Chronograph” having a dial with a track around its outer edge marked out in 300 divisions. Observations suggest that chronographs with 14,400 vph escapements and 240 divisions on the dial were based on traditional English movements with fusees, and that chronographs with 18,000 vph escapements and 300 divisions on the dial were based on going barrel movements. The 14,400 vph escapement was an old design, but the newer type of escapement operating at 16,200 vph made 4.5 ticks per second and 270 per minute, which was obviously inconvenient for a chronograph and does not appear to have been used. The elapsed time could therefore in theory be read to an accuracy of ¼ of a second. The use of 240 divisions was because the movement has a 14,400 vph escapement which ticked four times per second or 240 time per minute. The dials of early chronographs of this type were marked out with a track of 240 divisions around the edge, such as the one in the photograph here of a watch with a sterling silver case with London Assay Office hallmarks for 1878 to 1879. It is sometimes said that direct centre seconds was a twentieth century Swiss innovation, but that is wrong. This arrangement avoids the fluttering of the seconds hand of an indirect centre seconds arrangement. When arbor of the fourth wheel carries a centre seconds hand, the movement is called a “direct” centre seconds. If the watch is key wound and the hands are set from the back, it is easy to see that the second wheel is offset because the set hands square for the key is offset, or the opening for the key is not in the centre of the dome. #DENNISON POCKET WATCH CASE SERIAL NUMBERS FULL#By moving the fourth wheel to the centre of the movement, the seconds hand could be made longer to sweep the full radius of the dial rather than a small sub-dial. The fourth wheel rotates once a minute and, in a movement with a conventional layout, it carries the small sub-seconds hand. The movements of these watches were designed with the second wheel, which is usually the centre wheel, offset, so that the fourth wheel could be planted in the centre of the movement. They were probably popular because people liked the appearance of the dial, with its large, sweeping, centre seconds hand, rather than because they wanted to use them as chronographs (much like the enthusiasm for chronograph wristwatches today). There was no means of setting the seconds hand to zero, or recording more than one minute, which made them rather inconvenient to actually use as stopwatch. This caused the watch to stop keeping time when the chronograph function was used. These watches had a slide on the case band that caused a strip of metal to press against the balance staff, stopping the balance. In the late nineteenth century, centre seconds chronograph watches became quite popular in Britain. 189190 Clamshell Waterproof WatchĬentre Seconds Chronograph: Click image to enlarge. Bocks and Rams: IWC and Stauffer Trademarks.New product: Leather and Sterling Alberts.Savonnette and Lépine Watches and Cases.Converted Wristwatches - Transitional? No.Bears Galore! Three Bears and 0♹35 Silver.Borgel 2: Taubert & Fils and Taubert Frères.Borgel 1: François Borgel and Louisa Borgel.Straps for Vintage Fixed Wire Lug Trench Watches or Officer's Wristwatches
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