M E N U

Who Invented the Clock? The etymology - origin of the word Clock Why do the hands of our clock rotate clockwise ?? Horology .

.

...

...

.

Hourglass - Sand Clock How to Build a Sand Clock Ship Watches & Bell Ringing.

Sundial - Shadow Clock Sunrise-Sunset How a Sundial works How to build a Sundial .

.

....

.

Water Clock - Clepsydras . Ancient water clocks 1400 BC

Candle Clock Candles for time keeping Candle as an Alarm Clock Alarm Clock, the inside story Pictures .

.

...

...

.

Weights, Escapement, Bells Spring Devices Spring-Powered Clock Fusee+Verge and Foliot Balance beam and Crown Wheel Beginnings of Clockworks .

Pendulum Clock Escape wheel, pallets Anchor escapement Deadbeat escapement Hairspring in a Balance Wheel A clock with two pendulums .

.

....

....

.

Chronometer Measuring longitudes at sea John Harrison - Chronometer picture What is Longitude Latitude - Prime Meridian ? .

Electrical Clocks Quartz Crystal, Tuning Fork Battery Clock, Synchronous Electric Motor Piezoelectric Effect Quartz Watch History .

.

...

...

.

Sexagesimal Number System History of 60 seconds 60 minutes First American Clock Makers Eli Terry and Seth Thomas .

.

Second, Minute, Hour Day, AM, PM What is Standard Time Zones What is GMT, Greenwich Leap Second

....

.

Timekeepers Timeline Clock History 3500 BC to 2000 AD .

Calendar a History A History of the Western Calendar. Gregorian and Julian and Roman How the Days, Weeks Months, and Year got their names .

.

..

Comments & Awards | Poetry & Prose by F. E. Cummings |

Who Invented the Clock ? The etymology - origin of the word Clock Horology Historians do not know who or when mankind "invented" a time-keeping device or "clock". Probably thousands of years ago when someone stuck a stick in the ground and saw the shadow of the sun move across the ground, known as a Sundial. In ancient Egypt Water Clocks were used to keep time. The civil day in ancient cultures was made up of WATCHES. The length of the Watch varied with the season, and were called seasonal or temporal hours. The word CLOCK came into use in the 14th century AD. The science or art of measuring time or making timepieces is known as HOROLOGY The name CLOCK, which originally meant BELL, came into use when there were very large mechanical time indicators installed in bell towers in the late Middle Ages. These Clocks were not accurate. The origin of the word Clock Clokke = Middle English Clocca = Medieval Latin Cloc = Celtic and Old Irish Clugge = Old English Glocka = Old High German The word Bell has been used meaning to: chime, cry out, sound off, clamor Why do the hands of our clock rotate clockwise ?? The first mechanical clocks with hands were built to imitate the path of a sundial shadow. In the northern hemisphere, where sundials were in use for centuries, the shadow moves in a west to north to east rotation, which is what we call clockwise. @K6XF

The Sands of Time Hourglass - Sand Clock The Hourglass is an instrument for measuring time, it is of ancient origin. The date of its invention is unknown. It has also been called a Sand Clock. It can be designed for different time periods. It is a glass vessel which has two compartments. The uppermost compartment has a quantity of sand, water, or mercury which runs into the lower compartment during a period of time. The Sandglass was used by navies as a timekeeper and to find the speed of the ship. For measuring speed a log line was thrown overboard in which knots had been tied at regular intervals. By counting how fast the knots appeared, they could reckon how many "knots," or nautical miles an hour the ship traveled. The Sandglass was calibrated in seconds, or minutes or hours. For timekeeping the four-hour and half-hour Sandglass was used. The days at sea were divided into six four-hour WATCHES. The half-hour Sandglass was carefully tended, turning it as soon as the sand had run through and striking a bell for all aboard to hear. Likewise, at the end of four hours the hourglass was turned. This method of bell ringing and watches is still used aboard many ships to this day. Build a Hourglass or Sand Clock. Take two plastic bottles, put a small amount of sand in one of them, then place a piece of foil over the neck and punch a small hole in the foil. Now tape the two bottles together. @K6XF

Sundial - Shadow Clock Shadow Clock A vertical stick, gnomon, or obelisk that casts a shadow is a Sundial. and they were used as early as 3500 BC. In 1500 BC Egyptians had portable sundials. There is an Egyptian sundial from the 8th century BC that is still in existence. @K6XF  Sundial Sundials tell Apparent sun time, while your clock tells Mean Solar Time. Four times yearly Sundials and clocks agree. However, the Sundial time is sometimes 16 minutes faster and sometimes 14 minutes slower than your clock time. This difference is known as "The Equation of Time". There are tables available to use for converting the Sundial time to your local Mean Solar time. Sunrise-Sunset Equation of Time-Sun's Declination The earliest sunset occurs around 8 December each year, and latest sunrise occurs around 5 January. The day with the least amount of daylight is the winter solstice, the first day of winter, around 21 December. The longest daylight occurs at the summer solstice. Solstice occurs around 21 June, The earliest sunrise occurs around 14 June and the latest sunset around 28 June. There are two main effects that determine the times of sunrise and sunset, one is the declination of the Sun and the second is the Equation of Time, which is made up of the non-circular orbit of the Earth and the obliquity of the ecliptic. In January the Earth is closer to the Sun and is moving fastest in its orbit and in June it is farthest from the sun and moving slower. How to Build a Sundial Go Here @K6XF

Water Clock or Clepsydras Clep'sy'dras is a Greek word meaning kleptein,"to steal"; hydor,"water" Ancient water clocks from Egypt date back to 1400 BC. Ctesibius of Alexandria a Greek physicist and inventor improved the ancient Egyptian clepsydra in the 3rd century BC, in which water dripping into a container raised a float that carried a pointer to mark the hours. He attached a float with a rack that turned a toothed wheel where he put gadgets such as birds and ringing bells. The American Indian used a small boat as a water clock. There was a small hole to let water drip out and graduated lines on the inside of the boat to show the passing of time.. There have been water clocks that used a siphon to automatically recycle itself. Another interesting method was the cylinder into which water dripped from a reservoir with a float to provide readings against a scale on the cylinder wall. This cylinder water clock was used by the Romans. In the 16th century AD the Clepsydras were used by Galileo to time his experimental falling objects. Later in history an improved version was invented simular to the hourglass. The word Clock was not used until the 14th century. Water Clock drawings and how they work Go Here @K6XF

,,

Candle Clock Measuring the passing of time. Candle Timepiece Candles were used in ancient times as a device for measuring the passing of time by marking intervals along the length of the candle. The Candle was used as an Alarm Clock by putting a nail into the wax, whenever the candle wax melted down to the nail then the nail would fall into a tin pan and make a noise. In ancient times Egyptians used tallow, a substance of animals, to make candles. Romans were the first to use the wick, a heavy string in the middle of the candle. In the Middle Ages beeswax, taken from the honeycomb was used, however it was an expensive item. In the mid 1800's paraffin wax which is distilled from oil came into use. It burned clean and did not produced unpleasant odors. Today candles are still made from paraffin wax and heavy string for the wick. @K6XF

Weights & Escapement Devices Mechanical clocks with an escapement came into use sometime around 1285. These mechanical timepieces had a verge and foliot which were used for the mechanism that sounded a bell. The name CLOCK, which originally meant BELL, came into use when there were very large mechanical time indicators installed in bell towers in the late Middle Ages. These Clocks were not accurate One of he first public clock to strike the hour was in Milan in about 1335 AD. The clocks had only one hand, the hour hand. Weight driven clocks which were introduced before 1400 AD and regulated by a verge escapement. had mechanisms known as the verge and foliot or balance beam with a crown wheel, which resulted in a mechanical relaxation oscillator. Verge & Foliot Spring-Powered Clock The Second and Minute Hand The spring-powered clock was invented in about 1510 by Peter Henlein of Nuremberg, Germany, however the spring-powered clock did have its problems, that of slowing down when the mainspring unwound. The force of the mainspring is greater when fully wound than when it is almost run down. To solve this problem Jacob Zech of Prague, in about 1525, used a Fusee, or spiral pulley, to equalize the uneven pull of the spring. The fusee is a cone shaped grooved pulley used together with a barrel that contains the mainspring. Jost Burgi (1552 - 1632) has been credited with having invented the first clock with a minute hand in about 1577, however, it was not until the invention of the pendulum-regulated clock after 1656 that a minute hand became practical. The successive beats of a Pendulum made possible a practical second hand, which came into use in the very late 1600's. Eli Terry received the first clock patent issued in the United States and developed the techniques for mass production of clocks in the 1800's. @K6XF

,,

Pendulum Clock ¹ Escapement at the top Weight lower left Pendulum lower right The use of the pendulum rather than the foliot verge escapement was a giant step forward in timekeeping. In 1583 Galileo demonstrated that successive beats of a pendulum always take place in the same length of time, regardless of the distance through which the "pendulum do swing". The wheel or ring that replaced the verge and foliot escapement is called a Balance Wheel, which was first used in about 1400. However, the verge and foliot continued to be used until around 1650. In about 1656 Christiaan Huygens designed the first weight-driven clock with a pendulum instead of a verge and foliot escapement or balance wheel, and this made it possible to have some accuracy in timekeeping. It is believed Robert Hooke invented the first anchor escapement sometime before Huygens used it in his clock. The anchor escapement was invented about the time that the pendulum clock came into use. Huygen's design used a recoil escapement with an escape wheel and anchor with pallets called an Anchor Escapement. With the anchor escapement a pendulum swing was reduced from about 85 degrees to about 10 or 15 degrees, therefore much less energy is needed to keep the pendulum in motion which improved accuracy. And clocks could be made much smaller. The Pendulum has a natural frequency that is independent of amplitude and the frequency does not depend on the weight of the pendulum, only its length and the acceleration of gravity. The period of a pendulum is influenced by the strength of gravity which varies with latitude and elevation. The period of a pendulum will be greater on a mountain than at sea level. Other influences to the pendulum is caused by the room temperature, if it rises just 4 F degrees the clock will lose one second a day. If the pendulum has a length of 39 inches you can have a fairly accurate second hand.... But, if the pendulum is just .001 inch too long it will lose one second a day. There are methods to compensate for errors caused by temperature, for example the use of the metal alloy Invar. The minute hand begins to come into use in about 1680, and the second hand a few years later as the use of the pendulum developed. The Deadbeat Escapement George Grahamn of London, England in about 1720 modified the anchor escapement to eliminate recoil, creating the Deadbeat Escapement. The Grahamn Escapement improved accuracy to about one second a day, and it has been used in almost all finer pendulum clocks ever since In the year 1889 Siegmund Riefler built a pendulum clock with an accuracy of one-hundredth of a second. And then in about 1921 W. H. Shortt built a clock with two pendulums, one slave and one master, with an even greater accuracy. The master pendulum oscillated completely freely in a low vacuum. This clock was accurate to a few milliseconds a day. Hairspring and Balance Wheel Christiaan Huygens and Abbé d’Hautefeuille simultaneously developed the use of a spring or hairspring with the balance wheel and in 1674, which is still used today. However, Robert Hooke of London claims he invented and applied the hairspring to the balance wheel in about 1660. Adding a hairspring to a balance wheel improved the timekeeping and reliability of clocks greatly. ¹ Drawings by Gail Gibbons @K6XF

ALARM CLOCK The Candle was used as an alarm clock by placing a nail into the wax, whenever the candle wax melted down to the nail, then the nail would fall into a tin pan and make a noise. Large mechanical alarm clocks were in use by 1620 in homes. The alarm typically had a cam that rotated every 12 hours. There was a notch into which a lever would fall, releasing a train of gears that engaged a hammer, which repeatedly hit a bell. Seth Thomas I was a clock maker in Plymouth Hollow, Connecticut, which was renamed Thomaston in his honor in about 1860. He developed the small mechanical wind-up Alarm Clock which was patented by Seth Thomas II October 24, 1876. Father (1816-1888) Son (1785-1859). For Alarm Clock History from AD 1500's to the present Go Here o @K6XF

Chronometer John Harrison in 1761 built a marine chronometer with a spring and balance wheel escapement. It kept time on board a rolling ship to about one-fifth of a second a day during sea trials in 1762. This Chronometer gave the means of determining longitude to within one-half degree. The British Board of Longitude announced an awarded of 20,000 pounds in 1714 for an accurate chronometer for determining longitude on board a ship at sea. However, it required the aid of King George III to intervene in 1773 for the money to be given to Harrison. Harrison's No. 4 Chronometer * "In 1767, the French astronomer for the Navy, Charles Messier (b.1730 - d.1817) took part in the only naval journey in his life, in order to test and regulate some new marine chronometers, constructed by J. Le Roy. He sailed on the ship L'Aurore for a three and a half-month voyage in the Baltic, together with his colleague Alexander-Guy Pingre. Messier did the astronomical observations and Pingre the necessary calculations. If we compare the chronometers made by Harrison and Le Roy with the clock constructed by Isaac Thuret according to Huygen's invention, the conclusion is clear. Essentially, Le Roy's solution is a highly improved version of the Thuret clock with the escapement almost free from the driving train and the balance adequately compensated for temperature effects. These refinements may seem simple, but their development took almost a century." * * For a detailed history of the Chronometer Go Here @K6XF

Electrical Clocks Battery - Synchronous - Tuning Fork - Quartz Crystal Battery Clocks In 1840 the first Battery clock used an electrical impulse to operate the dials of a centrally located master clock. The electric current replaced the weight and spring as a source of power. Then in 1906 the first self contained battery driven clock was invented. The master clock system using electricity gives a direct impulse to the pendulum which in turn moves the clock’s gear train. Synchronous Electric Motor Clock The synchronous electric motor came into use in 1918. Patented by Henry Ellis Warren in 1916. The synchronous electric motor runs in step with the frequency of the electric power source which in the USA is 60 cycles per second. The electric motor is coupled to a reduction gear that drives the clock’s hands. A synchronous electric motor being used in a clock is wholly dependent on the frequency stability of the AC current which is supplied by the power company. The synchronous electric motor clock can be made into a precision time instrument by the use of the tuning fork. ²The Tuning Fork Invented sometime before 1752 by John Shore, A Tuning Fork is a U-Shaped two pronged steel bar. It can be tuned to an exact frequency and retains that for many years. It produces a pure tone, without any hormonics or overtones. The first Tuning Fork Clock (fork-clock) by N. Niaudet was described at the Academy of Sciences on December 10, 1866, and which was shown at the expositions of the University of Paris in 1867. Quartz Crystal The piezoelectric effect was discovered by the Curie brothers in 1880 Pierre and Paul-Jacques Curie. The first Quartz Crystal was applied in a clock in 1929. W.A. Marrison and J.W. Horton invented the original quartz clock, which at that time was very large indeed. The quartz crystal can be designed to oscillate at high frequencies such as 100,000 cycles per second. The use of the quartz crystal is known as the piezoelectric effect. This property exhibited by certain crystals of generating a voltage when subjected to an electric field causes it to oscillate a given frequency. If a 100,000 cycle per second frequency is subjected to a combined electrical and mechanical gearing reduction of 6,000,000 to one ratio, then the second hand of the synchronous clock will make exactly one rotation in 60 seconds. This clock can have an accuracy of one second every 10 years. ²The piezoelectric effect using quartz crystals was discovered by the Curie brothers in 1880, and in the years following was studied extensively by them. They found that when quartz and certain other crystals are stressed, an electric potential is induced in nearby conductors and, conversely, that when such crystals are placed in an electric field, they are deformed a small amount proportional to the strength and polarity of that field. Want more technical information on the Tuning Fork and Quartz Crystal?: ²The Bell System Quartz Watch History Go Here The Quartz Clock was substantially surpassed by The Atomic Clock. @K6XF

The Second The Second is the basic unit of time measurement in the International System of Units. For many years, until 1956, the second was defined as 1/86,400 of the mean solar day. Advances in physical science in the years following World War II made necessary a more precise definition, and the second was redefined as 1/31,556,925.9747 of the tropical year, as standardized at zero hours, minutes, and seconds on December 31, 1899, by international agreement in 1956. This definition was accepted until 1967, by which time the need for a still more precise and unvarying standard of measurement had become apparent. Scientists abandoned the use of larger, changing bases and decided to redefine the second in terms of electromagnetic wavelengths, that is The Atomic Clock. The Second is now established as 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of cesium-133. The Atomic Clock, with an accuracy of better than one second in six million years, known as the NIST-7, (in service from 1993 to 1999) differs from its predecessors in that the process used for selecting and detecting atomic states involves laser-manipulation rather than magnetic-deflection methods. This was the first major change in design for cesium-beam frequency standards. NIST F-1 Atomic Clock is referred to as a fountain clock, it is the new cesium atomic clock at NIST's Boulder, Colorado Laboratories and it is one of the most accurate clocks in the world, LEAP SECONDS "Civil time is occasionally adjusted by one second increments to ensure that the difference between a uniform time scale defined by atomic clocks does not differ from the Earth's rotational time by more than 0.9 seconds." For more detailed information from USNO Go Here The Minute The Minute in timekeeping equals 60 seconds. The Hour The Hour in timekeeping is 60 minutes. AM and PM A.M. or AM -- Before noon; ante meridiem or ante meridian. Latin = "before midday." The portion of the day between midnight and the following noon. Also written as a.m. or am P.M. or PM -- Afternoon. Latin = post meridiem or post meridian. Also written as p.m. pm      Longitude - Latitude - Prime Meridian The Alexandrian astronomer Ptolemy created a world atlas in the second century A.D. and plotted latitude and longitude lines on his atlas. Ptolemy had placed the zero (prime) meridian off the west coast of Africa. In the eighteenth century, the zero meridian was at times placed at London, Paris, and Berlin. It was not until 1880 that Greenwich, south of London, England was selected as the Prime Meridian for all maps. However the mariner needed an accurate clock to find longitude. @K6XF Longitude are imaginary lines drawn on a map of the world from the north pole to the south pole. The 0° longitude which is located at Greenwich England is called the Prime Meridian. The accurate determination of longitude is made by the use of a Chronometer which was not available until John Harrison's invention in the late 1800. Go Here for more information. International Date Line --- This meridian is located at 180° longitude out in the Pacific Ocean. This is the meridian that marks the place where navigators change their date by one day on a transpacific voyage. East of the line it is one day earlier than to the west of the line. Latitude --- These are imaginary lines drawn on a map of the world gives the location of a place north or south of the equator ranging from 0° at the equator to 90° at the poles. And the determination of latitude can be made using a Sextant, invented in about 1730 by Thomas Godfrey. To determine a position on Earth longitude and latitude provide navigators a means of maping any location on Earth. At the equator one degree of longitude is 69.17 miles and at the poles the meridians converge. One degree of latitude is 68.70 miles at the equator and 69.41 miles at the poles. The earth rotates 15 degrees of longitude per hour, so the earth's 360 degrees were divided into 24 zones and each zone measures 15 degrees in width. Meridian --- Any of the lines of longitude running north and south on a globe or map of the earth. The passing through the highest point in the daily course of any celestial body. At midday any place on the surface of the earth when the sun has reached its highest apparent point the sky. Standard Time Zones These time zones were created in 1883 At longitude in the USA: 75° EST, Eastern Standard Time 90° CST, Central Standard Time 105° MST, Mountain Standard Time 120° PST Pacific Mountain Time The prime meridian, which is zero (0) on the above map is located at Greenwich, England. These are Longitude lines Before Time Zones every major city and region set clocks according to local astronomical conditions. This created confusion as to when the trains were to arrive or depart. Time zones were first used by the railroads in 1883 to standardize their trains schedules across the USA. In 1918, the U.S. Congress made the United States rail zones official under federal law. @K6XF Daylight Savings Time was suggested by Benjamin Franklin in 1784. However, it has been used in the United States only since World War I when it was adopted in order to conserve fuel needed to produce electric power. Most states went back to standard time after WW I. During World War II the U.S. Congress passed a law putting the entire country on what was called “war time,” which set clocks 1 hour ahead of standard time for the duration of the war. In 1966 the U.S. Congress enacted the Uniform Time Act which established daylight savings time throughout the United States and its possessions. States where their legislature voted to keep standard time were exempted. U. S. Legislation enacted in 1986 put daylight savings time to begins at 2 AM on the first Sunday of April and end at 2 AM on the last Sunday of October. Greenwich Mean Time GMT Since the earth rotates 15 degrees of longitude per hour, the earth's 360 degrees were divided into 24 zones, each measuring about 15 degrees in width. Time zones to the west of Greenwich decreases by one hour, but going east they increase. Greenwich Mean Time is the mean solar time at the prime meridian of zero known as GMT (0) from which time in other zones are calculated. This was officially established in the year 1884. Latitude is the location of a place north or south of the equator and it is expressed by angular measurements ranging from 0° at the equator to 90° at the poles. The Day The civil day in ancient cultures was made up of "Watches". The length of the watch varied with the season, and were called seasonal or temporal hours. They were related to the length of the Sun’s time above the horizon. This method was known as far back as 1800 BC and was used until the end of the 13th century AD in Europe. This was the practice of the Greeks, the Sumerians and Babylonians, the Egyptians, and the Romans, and of Western Christendom so far as civil reckoning was concerned. In about the 13th century AD the seasonal method became inconvenient to use because of the invention of the mechanical clock. The seasonal method was uneven and the mechanical clock had an even 12 hours for day and 12 hours for night. The 12 comes from Babylonian 2 x 12 = 24 (5 x 12 = 60). This is known as the Sumerian Sexagesimal System based on the number 60. The Sumerian culture developed the Sexagesimal number system more than 4000 years ago. And it has carried to this day, we use 60 SECONDS in a MINUTE, 60 minutes in an HOUR. Today the system used for the calendar is the MEAN SOLAR DAY. Mean Solar Day is the average of a solar day because the length of the day varies slightly during the year as the Earth rotates around the Sun. The orbit of the Earth makes the Sun appear to move eastward each day relative to the Stars. The Solar Day is about 4 minutes longer than the Sidereal Day. A Mean Solar day is 24 hours 3 minutes 56.55 seconds of mean sidereal time. A Sidereal Day is 23 hours 56 minutes 4.1 seconds of mean solar time. For more information on Sidereal Time and Ephemeris Tables Go Here For more information on how the new Atomic Clock keeps today's time: Go Here The First Clock Makers in America Eli Terry received the first clock patent issued in the United States and developed the techniques for mass production of clocks in the 1800's. Eli Terry learned how to make clocks and when he was 21 he went into business for himself in 1793 in Plymouth Connecticut. Seth Thomas was born in Wolcott, Connecticut in 1785 He went to work for clockmaker Eli Terry in 1807, and later he bought out Terry’s factory. The Seth Thomas Clock Company was one of the most prolific and long lived clock companies. For more information on the first clock makers in America Go Here @K6XF Calendar a History A brief history of the Western Calendar Gregorian, Julian and Roman Calendars. How the Days of the Week got their Names How the Months got their Names When was the Zero in use BC and AD Inventor Dionysius Exiguss. Timekeepers @K6XF © Bow Wave of Time --- by Floyd E.Cummings --- all rights reserved We are riding on the razor edge bow-wave of Time, The past just fell behind us, The present is only a microsecond and It just ended, The future is at hand. Timekeepingsite Timekeepers A dynamic creation @K6XF Lab All right reserved 1997 - 2009 This Cummings & Lucas website created and published by (Floyd) Ernie Cummings Web This Website