1680 This watch contains a balance spring. This invention controlled the rate of watches, making them much more accurate. The new technology was quickly adopted by watchmakers around Europe. The balance spring is adjusted by turning the index numbered 106 on the back plate. Louis Ourry, Paris Going barrel, verge escapement, balance with spring (P&E CAI-563)
aperture=f4.5 focal length: 60.0 mm exposure 1/200 sec ISO: 3200