This self-winding watch in a square silver case was made by Loehr in Vienna, Austria. Self-winding watches were first introduced in the 1770s. Dispensing with the need for a separate key, these watches were kept wound by the movement of the wearer. Self-winding was succesfully applied to wristwatches by Harwood in the 1920s and Rolex in the 1930s and became commonplace. View of mechanism.
© Science Museum / Science & Society Picture Library