down. The Geneva Society of Arts, reporting on this watch in 1777, stated that 15 minutes walking was necessary to fully wind the watch. In 1777 Abraham-Louis Breguet also became interested in the idea, and his first attempts led him to make a self-winding mechanism with a barrel remontoire. Although a successful design, it was too complex and expensive for it to be manufactured and sold. About the end of 1777 or early 1778, Hubert Sarton (:fr: Hubert Sarton) designed a watch with a rotor mechanism. Towards the end of 1778 he sent a watch to the French Academy of Sciences and a report was written which, together with a drawing, gave a detailed description of the mechanism. Sarton's design is similar to those used in modern wrist watches, although there is no evidence linking the 18th-century design to 20th-century developments. About the beginning of 1779, Abraham-Louis Breguet became aware of Perrelet's watches, probably through Louis Recordon, who travelled from Geneva to London via Le Locle and Paris. Breguet studied and improved the design, and made many self-winding watches from then to about 1810. Although a few self-winding watches and patents for them were made from 1780 on, for more than one hundred years these watches were rare, until the advent of the wrist watch. During the years 1776 to 1810 four different types of weight were used: Side-weight The weight pivots at the edge of the movement and can oscillate up and down. The movement of the weight is limited to about 40°. This is the most common design produced by many makers including Breguet. These watches were called jerking watches because, even with buffers, when the weight hit the case the whole watch would jerk. Center-weight The weight pivots in the center of the movement and rotates clockwise and anti-clockwise. The weight is supported by a bridge that blocks the rotation and it is limited to about 180°. A few movements were made by different makers. Rotor-weight Again the weight pivots in the center of the movement and rotates clockwise and anti-clockwise. However, there is no bridge and it can rotate 360°. Very few of these movements were made. Movement-weight Here the whole movement is pivoted in the case and acts as the weight. Only one example is known, made in 1806. As noted above, some watches used bidirectional winding and others used unidirectional winding. The latter is