HorologyHorology (the study of time; related to Latin horologium; ; , interfix -o-, and suffix -logy) is the study of the measurement of time. Clocks, watches, clockwork, sundials, hourglasses, clepsydras, timers, time recorders, marine chronometers, and atomic clocks are all examples of instruments used to measure time. In current usage, horology refers mainly to the study of mechanical time-keeping devices, while chronometry more broadly includes electronic devices that have largely supplanted mechanical clocks for the best accuracy and precision in time-keeping.
Water clockA water clock or clepsydra (; ; water thief) is a timepiece by which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel, and where the amount is then measured. Water clocks are one of the oldest time-measuring instruments. The bowl-shaped outflow is the simplest form of a water clock and is known to have existed in Babylon, Egypt, and Persia around the 16th century BC. Other regions of the world, including India and China, also have early evidence of water clocks, but the earliest dates are less certain.
ClockmakerA clockmaker is an artisan who makes and/or repairs clocks. Since almost all clocks are now factory-made, most modern clockmakers only repair clocks. Modern clockmakers may be employed by jewellers, antique shops, and places devoted strictly to repairing clocks and watches. Clockmakers must be able to read blueprints and instructions for numerous types of clocks and time pieces that vary from antique clocks to modern time pieces in order to fix and make clocks or watches.
Verge escapementThe verge (or crown wheel) escapement is the earliest known type of mechanical escapement, the mechanism in a mechanical clock that controls its rate by allowing the gear train to advance at regular intervals or 'ticks'. Verge escapements were used from the late 13th century until the mid 19th century in clocks and pocketwatches. The name verge comes from the Latin virga, meaning stick or rod. Its invention is important in the history of technology, because it made possible the development of all-mechanical clocks.
Crystal oscillatorA crystal oscillator is an electronic oscillator circuit that uses a piezoelectric crystal as a frequency-selective element. The oscillator frequency is often used to keep track of time, as in quartz wristwatches, to provide a stable clock signal for digital integrated circuits, and to stabilize frequencies for radio transmitters and receivers. The most common type of piezoelectric resonator used is a quartz crystal, so oscillator circuits incorporating them became known as crystal oscillators.
History of longitudeThe history of longitude describes the centuries-long effort by astronomers, cartographers and navigators to discover a means of determining the longitude of any given place on Earth. The measurement of longitude is important to both cartography and navigation. In particular, for safe ocean navigation, knowledge of both latitude and longitude is required, however latitude can be determined with good accuracy with local astronomical observations.
Striking clockA striking clock is a clock that sounds the hours audibly on a bell, gong, or other audible device. In 12-hour striking, used most commonly in striking clocks today, the clock strikes once at 1:00 am, twice at 2:00 am, continuing in this way up to twelve times at 12:00 mid-day, then starts again, striking once at 1:00pm, twice at 2:00 pm, up to twelve times at 12:00 midnight. The striking feature of clocks was originally more important than their clock faces; the earliest clocks struck the hours, but had no dials to enable the time to be read.
CycloidIn geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve. The cycloid, with the cusps pointing upward, is the curve of fastest descent under uniform gravity (the brachistochrone curve). It is also the form of a curve for which the period of an object in simple harmonic motion (rolling up and down repetitively) along the curve does not depend on the object's starting position (the tautochrone curve).
Shortt–Synchronome clockThe Shortt–Synchronome free pendulum clock is a complex precision electromechanical pendulum clock invented in 1921 by British railway engineer William Hamilton Shortt in collaboration with horologist Frank Hope-Jones, and manufactured by the Synchronome Company, Ltd., of London. They were the most accurate pendulum clocks ever commercially produced, and became the highest standard for timekeeping between the 1920s and the 1940s, after which mechanical clocks were superseded by quartz time standards.
Time in physicsIn physics, time is defined by its measurement: time is what a clock reads. In classical, non-relativistic physics, it is a scalar quantity (often denoted by the symbol ) and, like length, mass, and charge, is usually described as a fundamental quantity. Time can be combined mathematically with other physical quantities to derive other concepts such as motion, kinetic energy and time-dependent fields. is a complex of technological and scientific issues, and part of the foundation of recordkeeping.
