This very fine watch does not appear in Berthoud?s register although the watches with the preceding number and following number do appear. It is not unknown for Berthoud?s watches to be missing from his registers and in fact Berthoud No. 15 which does not appear in the register was bought by Breguet and sold by him as Breguet No.12. It seems to be the case that watches sold to other watchmakers either as completed watches or un-finished pieces were not noted in the registers. This is perhaps because Berthoud feared that if the watchmaker altered the piece it might reflect badly upon him at a future date. This watch is unquestionably a very fine example of Berthoud?s work and has survived in remarkably good condition. Berthoud Demi-Marine Watches Watches with detent escapements and quarter repeating were called ?Demi ? Marine? by Berthoud. This was to distinguish them from the true marine timekeepers which were precision scientific instruments. The Demi Marine watches were still of course precision watches, but the addition of the quarter repeating mechanism does have an effect on the timekeeping of the watches. The Demi ? Marine watches were sold to Berthoud?s best and wealthiest customers, the type of clientele that Breguet attracted. Pierre-Louis Berthoud (1754-1813). The son of Pierre Berthoud, counsellor and master-clockmaker at Couvet, Pierre-Louis Berthoud (known as Louis Berthoud) was born in November 1754 in Placemont, Canton of Neuchâtel. At 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 be initiated into precision clockmaking. Ten years later Ferdinand Berthoud retired to his property in Groslay, leaving his Paris workshop in the hands of Louis? brother Henry. On several occasions Ferdinand Berthoud had requested that his nephew be officially attached to his establishment, but the response was always negative. Disappointed, Louis Berthoud returned to Couvet. However, Henry commited suicide on June 29, 1783, and Ferdinand asked his nephew Louis to return to Paris to take over the business. Louis Berthoud seems to have arrived in Paris in the spring of 1784. On June 5, 1784, he became ?Elève Horloger Méchanicien de la Marine?. That same year Louis Berthoud married Thérèse Bezout, the niece and adopted daughter of Etienne Bezout, mathematician and member of the Académie des Sciences. It was not without some bitterness that Louis Berthoud worked in his uncle?s shadow. In 1812, he wrote: ?... I lived several years overwhelmed by the bitterest distaste. It is with a sentiment of the most profound recognition that I offer here to M. Monge, then Minister of the Marine, the respect and thanks that I owe to the goodness of his heart and to his fine spirit. I owe them also to M. Thevenard... for having helped me to emerge from the oblivion into which it seemed I should be for ever plunged.? Berthoud produced a series of lever watches after examining one such watch produced in England by Josiah Emery, and also a watch made in France on the same principles. However, he soon abandoned the lever escapement in favor of the detent. He chose a pivoted detent escape-ment for a pocket longitude watch delivered to Chastenet de Puységur in 1787. Finally in 1792, following a proposal by the Bureau de Consultation, the Minister of the Interior awarded Berthoud the maximum prize of 6000 livres with distinction in the first class of national premiums for this watch. The mechanism of the watch, which is of an entirely new conception, is described by Louis Berthoud in a sealed document deposited in the Académie des Sciences 9 May 1792. It was this sum of money that allowed Berthoud to gain his professional inde-pendence. In 1804 the Ecole d?Horlogerie de la Marine was founded Seven pupils of the Ecole Impériale des Arts et Métiers at Chalons were chosen to be instructed at government expense. Following the Imperial Decree of 10 March 1806, Louis Berthoud was charged with the training of four of these pupils, Motel, Henriot, Saulnier and Laurent. In 1812 Louis Berthoud published his « Entretiens sur l?horlogerie à l?usage de la Marine ». In this short book, published a year before his death, Berthoud lavished on his pupils, in twelve ?conversations?, his last recommendations and advice, for exercising with success the difficult métier that they had chosen; Louis Berthoud had two sons: Jean Louis Simon Henri, usually called Louis like his father, (1793-1880), who on 17 April 17, 1819 married Thérèse Joly, the daughter of a watch-case maker; and Charles Auguste, (1798-1876), who married the second daughter of the same watch-case maker, Henriette Pauline Joly, on January 26, 1822. Louis Berthoud died at Chaillot 18 September 1813 at the age of 59. Literature: "La Longitude en Mer à l?Heure de Louis Berthoud et Henri Motel" by Jean-Claude Sabrier, Antiquorum Editions, Geneva, 1993.