French watch with a smooth case. The enamel dial is in the lower half, surrounded by a concentric graduated scale, on which the hand with the shining Sun indicates the negative or positive difference in minutes between true solar time and the mean time shown by the watch (this difference is called the time equation). The two small dials on the upper half of the main dial give the dates (left) and months (right). There is a fusee movement and a verge escapement.