This is perhaps the only surviving example of such an ingenious repeating mechanism working without springs. Mentioned by Pierre Le Roy in his Hommage à Julien Le Roy, published in 1760 in his Etrenues Chrouonnetriques, it was invented to avoid the frequent troubles in repeating watches causai by the traditional repeating train. The invention met with moderate success, probably because of its unusual way of repeating the hours "in six", but interested several horologists all over Europe, including Ferdinand Berthoud : Histoire de la Mesure du Temps, 1802, Vol. I, 154; F.A. Schmidt : Beltragt zur Zeitmzsskunst, 1797; and T. Reid : Treatise, 1826, p. 332. Beside the unique repeating system, it is most unusual in having subsidiary seconds slightly offset on the dial, between V and VI. The Property of Sir William Pennington-Ramsden, Bt., when sold by Christie's in London on 11 June 1975, this watch was coming from Charles; Marquis of Rockingham (1730-1782), Lord of the Bedchamber, Trustee of Westminster School and Governor of Charterhouse; a leading Whig Minister in charge of the Treasury just before his death. PIERRE LE ROY (Son of JULIEN) 1717-1785 Born in Paris on the 25 November 1717, Pierre Le Roy carried out his apprenticeship and spent his whole career in the family workshop. He took over its direction at his father's death, in 1759. Not only did he use the same signature, but it seems that he \vas also known in the trade under his father's name: Julien Le Roy. Thus, on 14 October 1775, during his visit to Paris, Dr. Johnson, wrote in his diary: "Then we avent to Julien Le Roy, the King's watchmaker, a man of character in his business, who showed a small clock to find the longitude - A decent man". At this period as Julien Le Roy had been dead for sixteen years, the clockmaker could only have been Pierre. On the other hand, in September 1771, a report to the Royal Academy of Sciences begins thus "Monsieur Le Monnier and I have been asked by the Academy to examine a new watch proposed for the use of astronomers and sailors, and executed by Monsieur Julien Le Roy... It is obvious that this watch had been made by Pierre Le Roy. Once again, this confusion shows that Pierre used his father's name in his business. As far as watches were concerned, four elements allow us to date them, and to distinguish those made in the workshop after Julien's death. To begin with, there is a considerable quantity of watches , in their original cases, which can be dated precisely by hall- marks stamped inside the case. For those which have Iost their original case, the chronological order of the numbers engraved on the movements allows them to be dated, taking as a oasis of comparison, the numbers on the watches whose date of manufacture is known from hallmarks. Then, Pierre Le Roy used for some of his simple watches the "fusée renversée" invented by his brother Jean-Baptiste in 1760, and a dead beat frictional escapement derived from that of Sully. The watches including these two last inventions, which bear relatively high numbers, fit chronologically among those produced between 1760 and 1775, and therefore after Julien's death. These three elements for determining the date of manufacture (case marks, chronological order of numbers, and technical characteristics) permit us to ascertain a fourth, which makes it much easier to identify the watches made by Pierre Le Roy after his father's death. Doubtless to render him bornage, the gilt metal cock on all those is chased and engraved with the initiais "J.L.R.". There is no exception to this rule. The only watch movements without it are those "for the use of astronomers and sailors", whose balance, provided with a device for counteracting the effects of temperature, is held in place with a single bridge. Pierre Le Roy presented many papers to the Academy, concerning both watches and docks. However, it is in the field of marine clockmaking that it possible to speak of his true genius, so important is his work here. In 1748 he conceived a detent escapement whose design, published by Gallon in Machines et inventions approuvées par l'Académie Royale ries Sciences does not entirely explain its way of functioning. But it does show the first attempt to make an escapement which ensured the balance complete freedom of motion, outside the phases of unlocking and impulse. In his Précis des recherches ..., Pierre Le Roy mentioned in 1768 a work that he had already announced in 1750, called: Essai rte physique et de dynamique sur les ressorts des corps, which vas never published. The manuscript of this essay, which has just been discovered, shows that from this period, his researches on friction, the elasticity of springs and the phenomena of metal dilatation had led him to conceive a primitive form of equalising winder and a mechanism to compensate the effects of temperature on the functioning of watches. The sealed envelope, which had been deposited at the Academy on 18 December 1754 and opened at his request on 28 June 1763, already contained the essential principles which allowed him to design the marine clock which he presented to the King in 1766 and with which he won the longitude prize, offered by the Academy. to 6e contirrued 112 Duc de ûoDD~Il ie.cfu.r cJ'rurcbr?i,r (;.R euz?t1?il )i/'irni nc? ~J'i iiiii/n .~cS~ '-itrcipi rte ~l~unrirri ~onzitri 6af'UÎZ Lt.X'a/1.i--)/Y oeothaeirrfi,ret urii <~n,i+,~Prfrz.>?. / ü t i,rr?+r wrrna,CX.+YS «". ~/iinSi ..11-D"q: x;,,x mr J, ,...? aurrn.ri ,t ?, -,,,, ,?,:. ?iL~:/.,,r,r,,, 7r ,rr,v,.,.+?.:,- t% ar.?:r r/.i-SC................................. ;, ,.: ::. ~_........:-........................... © Bibliothèque Nationale DUC DE LORRAINE Charles-Alexandre de Lorraine was born on 12 December 1712 at Lunéville (France). The son of Duke Léopold and Elisabeth-Charlotte of Orléans, he studied under leading teachers, thanks to whom he excelled in the arts and sciences. Serving in the army of the Holy Roman Emperor he saw action against the Turks, and in 1741 he \vas given command of the Queen of Hungary's army. In 1744 he married the Archduchess Maria-Anna. Appointed Governor General of the Low Countries, he vvas soon obliged to put himself at the head of the Rhine army. His numerous military successes did not stop him from bringing this career to an end in 1757. The rest of his life was devoted to the government of the Low Countries, and especially to the development of their commerce and agriculture. I-Ie founded the Brussels Academy, a public library, and the free School of Painting and Sculpture. As Governor he so endeared himself to the peoples he ruled that in 1775 the Brabant States General had a full size bronze statue of him erected in one of the neh' squares of Brussels. He died at the Château of Tervueren near Brussels on 4 July 1780. 113 This was the first marine clock ever made, which included the three fundamental discoveries which were responsible for the success of marine clocks and watches, and later modern chronometers, a free escapement, an isochronic hairspring, and a self-regulating pendulm, the compensation for the effects of temperature taking place directly on the pendulum, without touching the hairspring, so as not to disturb its isochronism. In September 1771, Pierre Le Roy presented to the Academy a "Memoire concernant une montre de nouvelle construction pour l'usage de l'astronomie et de la Marine". This was a precision pocket watch, placed in gimbals for use at sea. One of these watches \vas tried out during the voyage of Verdun de la Crenne, in 1771 and 1772, but did not give the hoped-for results. Supplied with a compensation for the effects of temperature they nearly all had a dead beat escapement derived from that of Sully. Because of their shape, Pierre Le Roy gave them the name of "petites rondes". In 1773, as he was ill, Pierre Le Roy vas obliged to l'est at the Château de Moisan, and restrict his activity. He was disappointed to learn that the office of Clockmaker Mechanical Expert to the King and the Navy had been awarded to his rival Ferdinand Bethoud, with the position of General Machinery Inspector for the Navy. He devoted himself to writing Suite du précis sur les montres marines en France avec un supplément au mémoire sur la meilleure nranière de mesurer h' teins en mer. In 1780, he gave up all activity in order to retire to Viry-sur-Orge where he silent the Iast five years of his life.