As opposed to similar regulators made by Robert Robin at the same period, mantel regulators made by Lepaute are extremely rare and their remontoir, of entirely original design, are fitted with fly regulator, a small horizontal lever, lifted every five seconds by the mainspring barrel.Pierre-Michel Lepaute, Paris, came in partnership with his father in 1811. They used to sign: Lepaute & Fils and their workshop was in the rue Saint Thomas du Louvre. His father sold him the business in 1816. Among others, he made a clock for the building of the Bourse, in Paris. For this he was paid30,000 Francs. He was 64 when he died in 1849. He was succeeded by Augustin-Michel Henry who was the son-in-law of Jean-Joseph and the son of Pierre Henry.Pierre-Louis Berthoud, (1754-1813), known as Louis Berthoud, was born in November 1754 in the hamlet of Placemont, near Couvet, in the Val de Travers, Canton of Neuchâtel, Switzerland. At the age of twelve, he began his apprenticeship in his father's workshop. He was hardly fifteen when his exceptional skill was noticed by his uncle, the famous Ferdinand Berthoud, who invited him to Paris to complete his training and be initiated into precision clockmaking.When Louis Berthoud arrived in Paris in 1769, Ferdinand Berthoud already had one apprentice, Jacques-Vincent Martin, taken on in 1767 to help in the construction of marine clocks Nos. 6 and 8 ordered by the crown. Ten years later Ferdinand Berthoud retired to a property he had acquired in 1767 at Groslay, Valley of Montmorency, to devote himself entirely to his research. He left responsibility for his Paris workshop to another nephew, Henry Berthoud, Louis' brother, who commited suicide on the 2June 1783, leaving the workshop virtually bankrupt with more than 60,000 livres of debts.Ferdinand Berthoud then wrote to his nephew to persuade him to return to Paris to take over direction of the business and to restore it.Louis Berthoud arrived in Paris, in the first days of May 1784. The same year Louis Berthoud married Thérèse Bezout, the niece and adopted daughter of the geometer Etienne Bezout, mathematician and member of the Académie des Sciences.After having tried the lever escapement, he decided to adopt the pivoted detent for a pocket longitude watch, that he delivered to Chastenet de Puységur in 1787. This watch already displays all the essential characteristics of all the chronometers of his production. The mechanism of this watch, which is of an entirely new conception, is described by Louis Berthoudin a sealed document deposited in the Académie des Sciences9 May 1792.In 1794 Louis Berthoud decided to leave the workshop in the Rue Harlay to establish himself at Argenteuil in a house that he had just bought.The 24 Vendemaire, An XI (16 October 1802), a consular decree awarded him the title Horloger Mécanicien de la Marine with a salary of 1000 Francs, and by a decision of 16 MessidorAn XIII (5 July 1805) the Bureau des Longitudes appointed him Horloger de l'Observatoire et du Bureau des Longitudes.The Ecole d'Horlogerie de Marine was founded by Imperial Decree of 10 March 1806, and Louis Berthoud was charged to train four pupils, Motel, Henriot, Saulnier and Laurent and in 1812 he published his Entretiens sur l'horlogerie à l'usage de la marine.Louis Berthoud died at Chaillot 18 September 1813 at the age of 59 after a diabetic coma.Literature:J.-C. Sabrier: La Longitude en Mer à l'Heure de Louis Berthoud et Henri Motel, Antiquorum Editions, Genève 1993.