Julien Le Roy (1686-1759). Is one of the clockmakers who have contributed most to the progress and the reputation of French watch- and clock-making. Born in Tours on August 6, 1686, he came to Paris in 1699 and was received master in 1713. The following year he married Jeanne Lafons and established himself in the rue du Harlay. First member, then Director of the Société des Arts, he improved almost all branches of clockmaking, and many important inventions in the realm of time-measurement are owed to him. In 1717, Julien Le Roy presented an equation clock to the Royal Academy of Sciences which showed the true time, the place of the sun and its declination. Appointed Clockmaker to the King in 1739, he had his private quarters in the Louvre. His inventions concerned, among other things, turret clocks, equation-clocks, and pull-repeat mechanisms which, previously hidden under the dial, were arranged on the back plate so as to make them more accessible and ensure easier adjustment and maintenance. He developed a double anchor escapement, with dimensions suitable for making the vibrations isochronic, by making the arms the same length as the radius of the wheel. However, his most important discoveries concerned watch mechanisms. The adjustable potence for the verge escape wheel considerably improved the escapement?s functioning, and the steel end-piece (coqueret) which allowed oil to be retained in the balance pivots in order to diminish frictional force, was quickly adopted by other watchmakers. The inventor of dumb repeating watches, in 1740 he created a new arrangement which allowed the area allotted to the repeating work to be enlarged. This invention, called "à bâte levée", was also adopted by his fellow clockmakers. In 1755 he invented a small anchor escapement used as a regulator for the repeating train. He contributed to the Encyclopédie by writing several articles on clock-making together with his son Jean-Baptiste, the Academician.