Dates
3000- Sumerians first lunar calendar
2481- Egyptians adopt 365 day calendar or 4241?
2000- Babylonian successors take Sumerian lunar calendar
1500- Egyptians invent water clock
575- Sundials brought to Greece from Babylon
550- Babylonians discover Saros period
. .- Water clock known in Greece + sundial introduced
500- Greeks find Metonic cycle- after Meton who brought it to Greece from Babylon
. .-Babylonians invent the 19 year lunar calendar
380- Greek astronomer Eudoxus calculates length of a year- 365 days and 6 hours
300- Greek geographer Dierarchus draws latitude lines
290- Romans erect public sundial
250- hourglass invented
. .- Egyptian reformers suggest leap years, but not passed
220- Greek astonomer Eratosthenes calculates obliquity of ecliptic
150- Clepsydra introduced into Greco-Roman empire from Egypt
130- Greek astonomer Hipparchus determined period of axis precession is 25800 years & 10 years later found the year is less than 365 days 6 hours
46BC- Caesar makes year of confusion 445 days to set calendar right (consulted Sosigenes of Alexandria)- then the next year he instituted first
. . .leap year every 4 years Feburary has extra day-> Julian Calendar gained 1 day every 128 years
321- Constantine changes week from 8 day to Christian 7 day
325- Council of Nicaea adopts Metonic cycle, Eusebius chronology, 7 day week, and fixed way to determine Easter
. .- Eusebius (church historian) makes chronological table begining with Abraham
358- Jews adopt Babylonian 19 year calendar
400- The Angles & Saxons bring 5 day week to England with our Mon.-Fri. names
527- Dionysius Exigenus, abbot of Rome, moves New Year from Jan1 to Mar25, fixes Christmas to Dec25, and starts dating events BC
800- Arabian caliph Harun al-Rashid sends mechanical clock to Charlemange, Europeans can't duplicate
901- Begining of oldest Hopi calendar- "notch in stick each day"- still preserved
1088- Chinese mandarin Su Sung develops the verge escapement (mechanical clock)
1300- Europeans begin to make mechanical clocks
1330- the hour is made constant
1410- Italian architect Brunelleschi makes spring driven clock
1472- Regiomantanus (Johann Miller) uses weight driven clocks in observatories
1502- Peter Henlein builds first pocketwatch
1581- Galileo in Cathedral of Pisa discovers pendulum
1582- Pope Gregory 13th on advice of Chris Clavius drops 10 days from the next year-> Gregorian calendar- accurate to 1 day every 3323 years
1610- Galileo suggests Galilean moon eclipses as a way to determine longitude at sea
1644- Mersenne calculates seconds pendulum = 39.1 inches
1657- Huygens develops a pendulum clock: before this clocks off by 5 minutes
1660- Hooke invents the anchor- an escapement which improves function of gear train
1671- William Clemont makes anchor escapement- confines pendulum to cyclodial 3-4 degree arc
1675- Huygens develops hair-spring (balance wheel) as substitue for pendulum
. . - Charles II founds the Greenwich Observatory
1700- Denmark + Protestant Germany adopt the Gregorian calendar
1715- G. Graham invents the Graham, or deadbeat escapement: pendulum oscillates with little interference
1735- Harrison's first longitudinal clock
1752- England and American colonies adopt Gregorian calendar and move New Year to Jan. 1
1760- John Harrison makes marine clock: loses 5 seconds in 9 week trip
1792- French revolutionaries adopt metric calendar: holds for 13 years
1849- Auguste Comte of France proposes calendar similar to Moses'
1878- Sandford Fleming of Canada proposes time zones
1883- US divided into 4 time zones- Pacific, Mountain, Central, and Eastern Standard
1884- Washington Meridian Conference: prime meridian set at Greenwich
1887- World calendar idea started
1907- William Willet argues for Daylight Savings Time, not adopted; dies in 1915 1 year before DST adopted
1911- China adopts Gregorian calendar
1916- Daylight Savings Time adopted
1918- Russia adopts Gregorian calendar
1928- Parliment tries to make the date of Easter more sensible, but fails
1929- USSR tries 5 day week then 6 day week in 1932 ends 1940
. . - Dr. Warren A. Marrison builds first quartz crystal clock
1930- Elizabeth Achelis devises the World calendar
1956- World calendar presented to UN and fails
1960- Atomic clock built, off 1 second in 30,000,000 years
. . - laboratories average atomic time scales to come up with Universal Coordinate Time (UTC)

The Second
Prior to 1956 one second was defined as the fraction 1/86,400 of the mean solar day.
From 1956 to 1967 the emphemeris second was defined as the fraction 1/31,556,925.9747 of the tropical year at 00hours 00minutes 00seconds on December 31, 1899.
Today the second is defined as the duration of 9,192,631,770 periods of the radiation of the cesium- 133 atom between two hyperfine lines.

Roman Numerals
I = 1 . . V = 5 . . X = 10 . . L = 50 . . C = 100 . . D = 500 . . M = 1000 . . MCMXCVII = 1997

Wierd Words
clepsydra = water stealer
Egyptian hour = wnwt
Italian with Celt origin, clock = clcea
Greek, sundial = gnomon = "one who knows"
Sumerian, month = danna : day = ges
German, glocke = bell
Greek, eclipse = "left out"
Latin, equinox = "equal night"
Latin, vernal = "spring"
Latin, solstice = "stopping of the sun"
Mayan + Aztecs, year = lamat
Fortnight = fourteen nights
Sennight = seven nights
Greek god Chronos -> chronology

Rhyme Time
Thirty days hath September,
April, June, and November,
All the rest have 31,
Excepting Feburary alone,
Which has 28 days clear,
And 29 in each leap year.