To minimize friction in the most important bearings, jewels are affixed to the anchor pallets and ellipse. Various jewels are the bearing jewels, endstones, pallet jewels and impulse-pins. A movement with a large number of jewels doesn’t necessary mean that that movement is of particularly high quality. Just the opposite: it is often the case that the dials of cheaper watches indicate that a great many jewels have been set into the movement, thus suggesting that the movement must be of good quality. In such watches, however, the jewels are only rarely placed at locations where they could truly serve some worthwhile purpose. A precision hand-wound watch requires at least 15 functional jewels: 10 bearing jewels, 2 endstones for the balance, 2 pallet jewels for the anchor, and 1 impulse-pin (ruby pin). An optimal arrangement can be achieved with 18 jewels. In complicated watches (e.g. a watch with automatic winding, chronograph functions or repeater chimes), the minimum number of necessary jewels increases.
The international designation for the rubies or other stones in a watch-movement.
A jump seconds (also dead beat seconds, seconde morte in French) means that the seconds hand of a watch makes one move per second and in the time within two seconds, just \"stands still\". The opposite is called the \"Sweep second\" (Seconde trotteuse in French) which is more common in mechanical watches. Here, the seconds hand moves five times/steps within one second´s time. Since these steps are very small, the human eye can hardly distinguish between one and the next. They are rather perceived as a gradual, very slow flowing movement. That is why the \"normal\" seconds are called \"schleichende Sekunde\" as a contrast to the jumping seconds.
A watch-movement in which the hour-hand has been replaced by a disk marked with the twelve numerals that correspond to the hours. A small additional mechanism ensures that this disk jumps ahead 30º at the conclusion of each successive 60-minute interval, thus allowing the next numeral to appear within the aperture cut into the dial.
Escapement by means of an anchor with pallets, also known as a Swiss lever escapement. Invented circa 1715 by English watchmaker G. Graham. Types of lever escapement include: English lever escapement, Glashütte escapement, Swiss lever escapement.
See phases of the moon.