Tourbillion
This arrangement of the train and escapement is the invention of A. L. Breguet and consists of a light steel framework in which the escapement of a watch was mounted upon the fourth pinion, taking the place of the fourth wheel. By this arrangement the escapement revolved, thus eliminating the position errors to a great extent. The arrangement of Brequet has been simplified by Bonniksen and is known as the Karrousel watch.