This is a very simple and ingenious escapement. The impulse is given by escape wheel pin directly to the impulse roller set on the balance staff, the locking is by a small lever fixed to the pivoted arbor, another similar lever is mounted for the unlocking. The escapement is simple to make (no need for cutting special escape wheel) and is also well performing detached chronometer one. Such chronometers were exhibited for the firs time at the Paris Exhibition of 1823. The only other clock knownof this type, is in the Musée National des Techniques (C.N.A.M., Paris), is described and illustrated in Hans Von Bertele : Marine and pocket Chronometers, page 168, fig. 167 a,b,c.Honoré Pons active in Saint Nicolas d'Aliermont from 1807, was one of the most eminent French clockmakers of the period. A tremendously versatile clockmaker and watchmaker, he designed and built his own machinery for clock production, devised his own type of movements which he sold to other watchmakers, such as Brocot, and which today are referred to as Pons calibers. He took part in numerous exhibitions, and won many prizes and medals. "Les Ouvriers du Temps", Jean-Dominique Augarde, Editions Atiquorum, Geneva, 1996."Dictionnaire des Horlogers Français", Tardy, Paris, 1972.Following the rapport made by Sayoye ROllin, Prefect of the region, setting out the precarious state of the horological industry, he was brought to Saint Nicolas d'Aliermont in 1806 by the Minister of the Interior in order to reorganize it. After a careful investigation into the 18th century methods used in Saint Nicolas, he formed the clockmakers into a sort of Guild called Fabrique d'Horlogerie de Saint Nicolas d'Aliermont, directed by himself and designed to co-ordinate their efforts and busness interests. He introduced the use of machinery, some of it of his own devising, and generally brought an industrial revolution to Saint Nicolas which became the main French center of production for the clock movements, known as mouvements de Paris, an later for carriage clocks and chronometers. The largest part of the production being sold as blancs-roulants, and finished in other centers, such as Paris. He was awarded silver medals in the Exhibitions of 1806, 1819, 1823, and a gold medal i1834.