"The Swiss Federation of Watch-Manufacturers' Associations (F. H.) defines the chronometer as follows: a watch that has obtained an official rating-certificate. In Switzerland, official rating-certificates are issued only by the observatories at Geneva and Neuchâtel, and by the SWISS Institutes for Official Watch Time-keeping Tests." (Berner)
"A chronometer is, etymologically, an instrument for measuring the time. With usage it has come to mean a high-precision watch displaying seconds whose movement has been controlled over a period of several days, in different positions and at different temperatures, by an official neutral body. Only mechanisms that have satisfied the criteria for precision of ISO 3159, or its equivalent, are issued with an official chronometer certificate.
In Switzerland, the Contrôle Officiel Suisse des Chronomètres (COSC) has the power to award these certificates. Based on the requirements of ISO 3159, the COSC has also drawn up a set of specifications for the testing of quartz movements." (FHH)
Ferdinand Berthoud FB1 Chronomètre
Ferdinand Berthoud FB1 Chronomètre (case back).
Marine Chronometer, historically, a large timepiece used for keeping time onboard a ship. Often made with a detent escapement; hung in gimbals to maintain a horizontal position regardless of the ship’s movements;
Seiko Marine Chronometer from 1942.
Seiko Marine Chronometer movement.
Seiko Marine Chronometer dial with power reserve.
Certification: "Procedure following which a third party gives a written assurance that a product, process or service meets specified requirements." (Berner)
Chronofiable®: "1. Complex machine for testing the reliability of finished watches and making it possible to age them 8 times faster than when worn. Programme consisting of various shocks and climatic cycles. 2. Name of the laboratory which carries out reliability tests based among other things on the Chronofiable machine." (Berner)
"A joint certification project by a consortium of watch companies which accelerates the watch's ageing process by a factor of eight to simulate the effects of six months' wear in three weeks. The majority of leading watch brands submit watches for testing and are issued with a Chronofiable certificate." (FHH)