How do you think about time?  How do you define time?   Answering these questions becomes a humiliating, humbling, and at the same time, an astonishing ethereal experience.  In the process you find yourself nearly paralyzed by being forced to simultaneously face ancient history and eternity.  Clearly it is an infinite project.   But by limiting ourselves to major historical developments in man’s time keeping, with a few obscure fascinations added, there is an unfolding understanding of everyday terms we seldom question – such as the calendar, the year, the month, the week, the day, the hour, the minute and the second.  Fundamental historical changes of time focus and definition have taken place with earthshaking violence, and at other times with barely perceptible comprehension.  The future is currently being molded by mind disturbing heated arguments about time, which will result in quantum dislocations as significant as the Copernican and Galilean discoveries.

 There is another way of defining time -- through Einstein’s famous E=MC² equation.  I am surprised there is not more discussion on this curious subject.  Rearranging the formula using fundamental algebra one can state that C²=E/M.  Since C is speed we can define it as D/T, so our equation becomes D²/T² = E/M.  Making another algebraic transform we find that T = DvM/E.  So there we have it, the ethereal thing called time, which has qualities we can’t taste, see, hear, feel, touch or weight defined in terms with which we are comfortable -- distance, mass, and energy, which are all everyday well understood entities.   All this is possible provided we understand that we have done a little slight of hand.  It is true that C is speed which is defined as D/T, but this is a very special kind of speed.  It is the speed of light.  So at this unique speed, the tangible replaces the intangible.  So perhaps we inadvertently found “God’s time” defined at this somewhat mystical velocity. 

  So what time is it?   Is it sundial time, mean solar time, sidereal time, local solar time, Daylight Saving Time or God’s time?  But leaving this aside for now you will recall that this discussion began with objections to the way time intervals are measured.  All of this is the result of embedded historical inertia -- currently so encrusted, that even though scientifically we would be better off to discard our present system – it is too late.    So we have 12 months to a year, approximately 30 days to a month, 7 days to a week, 24 hours to a day, 60 minutes to an hour and 60 seconds to a minute.  Where did all this come from?

 About 3000 B.C., the ancient Sumerians developed official calendars based on the 29 ½ day moon cycle.   This was adopted by the Babylonians and Egyptians.  The lunar month as a unit of time keeping is actually the origin of many interesting words we commonly use without understanding their historical background.  Since primeval times there has been a connection of the moon with measurement.    It turns out that the word “moon” in English and its cognate in other languages is rooted in the word “me” conveying the idea of measurement.  The Greek word is “metron” from which we get our English word “meter” and the word “measure”.  It is also the root of the late Greek word “menolgion”, which is the contracture of two words meno – meaning month and logy meaning account.  It is directly from this we have our English word menology referring to a calendar and is included in the title of this paper.  The word calendar derives from the Latin “calendarium” meaning account book since it was used to keep track of the dates when accounts were due.  Interestingly enough, the word menstrual is the same cognate “me” which curiously has a cycle close to the moon’s cycle.  Not to belabor the base 10 decimal system, I cannot help pointing out that the human gestation period is 10 lunar months.  So the moon figures importantly in the historical measurement of time, but unfortunately it is not useful for farmers and hunters that need a calendar for the seasons     -- to predict hot and cold. This is because moon cycles do not match up with solar cycles, which has resulted in a lot of thinking and tinkering trying to get things to come out right.^7.

 So long as man marked his life only by the cycles of nature – the changing seasons, the waxing or waning moon – he remained a prisoner of nature.  So he devised his own bunching of time.  These bunches were markedly varied but were generally cyclic.   From this the “Week” originated.   This is no western invention and it has not always been seven days.  At least 15 different ways of bunching time into “weeks” have been used.  These have varied from 1 to 20 days in length. The shorter week periods have been found in Africa and the longest in Mesoamerica.  “The Kedangese of eastern Indonesia are the creative record setters when it comes to fabricating week cycles.  They have ten kinds ranging in length from 1- 10 days, each with its own set of names, all running at the same time.  Furthermore, they seem to be able to calculate in their heads when every conceivable combination will recur in the maze of cycles that eternally preoccupies them.^8.

 How then did we come to have a seven day week?  Apparently the Greeks had no week.  Romans lived by an 8-day week.  Farmers worked the fields for 7 days and came into the city on the eighth day – the market day.  When and why they fixed on 8 days is not entirely clear and when and why they changed to a 7-days week is not clear.  The number 7 has had a magical charm in many cultures.  The Japanese had seven gods of happiness, Rome was set on seven hills, there were Seven Wonders of the World, medieval Christians enumerated seven deadly sins, we have the seven ages of man and Islam has their seventh heaven. And that is not the end.  There are the seven deacons, the Greek legend of the Seven Against Tebes, the Seven Champions of Christendom, the Seven Churches in the book of Revelation, Seven Sages of Rome, the Seven Seas, and The Seven Sisters in the constellation Pleiades.  There is the early Christian legend of the Seven Sleepers, and the Seven Virtues. And there is the popular superstition of the Seventh son.  He is supposed to be lucky with occult powers.  From this comes the “seventh son of the seventh son” a potent magician.  So it should come as no surprise that we have a seven day week.  No known edict, however, is known for the Roman transfer to 7 days.   It apparently happened about the early third century A.D.; about the time Christianity was accepted into the Roman Empire by Constantine in 325 A.D.   The Christians had brought the Jewish week with them including the naming of the 7^th day Sabbath.  This seems to have survived from the years when the Jews were in Babylonian captivity.  The Babylonians observed certain enumerated days – the seventh, fourteenth, nineteenth, twenty-first and the twenty-eight day – when certain activities were forbidden.^9.  

 Then there is another bunching of time which is near and dear to this group -- our fortnight.   The oldest reference to this term I could find is in the Oxford English Dictionary that references its Germanic use in “Laws of Ina” page 55 – where the word feowertyne niht occurs in the year 1000AD.   We now use it as a contracture of fourteen and night – two weeks of nights.  In 1530 it was still spelled with a “u” but by 1639 the “u” was dropped in an article appearing in the Hamilton Papers.  It is altogether fitting then, that we meet in the twilight hours to measure our passage of time, in terms of nights rather than days.

 So much for weeks and fortnights – the month most certainly relates to lunar cycles.   If there were exactly 12 lunar cycles in a solar year things would have been much easier, but as we have mentioned the lunar cycles don’t fit the solar cycle.  We know the Egyptians divided the solar year into 12 months.  “Their 12 lunar cycles that made up their lunar year come to 354 days – roughly eleven days short of the seasonal year.  This was solved by adding an extra month about every third year or so.”^10.    For a while they came up with an interesting variation to have just three weeks for their month, but each week containing 10 days giving them a 30 day month.  But of course this didn’t come out right at the end of the year either, so they added some extra days at the end for having parties. The Persians who had commerce and exchange of ideas with Egyptians also had 12 months of 30 days each.  But they differed from the Egyptians by having their months divided up into two seven day weeks and two 8 day weeks.  This arrangement gave them 5 intercalary days at years end like the Egyptians.^11. The ancient Jewish astronomers while in Babylonian captivity based their year on the movement of the sun, their months on phases of the moon and gave Babylonian names to their months.    They departed drastically, however, from the Babylonians and Egyptians by making some of their months “full” with 30 days, and some of their months “defective” with 29 days.  To get the lunar cycles to keep pace with the solar cycle they threw in a thirteenth month every third, sixth, eight, eleventh, fourteenth, seventeenth, and nineteenth years.   This gave them an underlying 19 year cycle which did a good job of keeping things in order.^12. 

 The formation and history of calendars in different civilizations is a fascinating subject but before leaving this subject, mention now is made of the unique Mayan calendar.   The Mayans of Central America used not only the sun and moon, but also the planet Venus to establish a 260 day and a 365 day calendar.^13.   These cyclic systems were intermeshed like interlocking gear trains. By turning these two cyclic systems backward they left a celestial-cycle record indicating their belief that the creation of the world began in 3113 B.C. because that is when both cycles simultaneously reach zero.  This is of interest, as it is not too different from Usher’s chronology of the earth’s age.  

 The hour glass was developed as a relatively accurate means of recording time.  It was independent of weather and very useful when at sea on a rocking boat.   It was this instrument that lead to determining a ship’s speed at sea.  To calculate the speed one would throw a piece of wood overboard with a knotted rope attached.  The knots were seven fathoms apart and one just counted the number of knots that passed through their fingers in a minute.  This then, is the derivation of the ship’s speed being measured in “knots”. ^14.

 Our present calendar dates back to 1582 when there was a convergence of political and religious tension over the problem that came up in regard to the date of Easter as it was determined by the calendar used in the western world up until this time, called the Julian Calendar.   This “old” calendar was replaced by Pope Gregory XIII and is known as the ‘new” calendar or the Gregorian calendar.     This was worked out by a large number of mathematicians and astronomers. The Julian calendar by this time was 10 days out of synchronization with astronomical time and required some radical changes.   Actually three changes were made:  the calculation of leap years was changed by eliminating three leap years every four Centuries, taking 10 days from the month of October, and beginning the New Year on January 1 instead of March the first, as it had been in the Julian calendar.  What Pope Gregory thought was going to be a relatively easy task turned out to be much different.   The Eastern Orthodox Church refused to accept it and if it hadn’t been for the Bolshevik revolution the Russians probably would still be using the Julian calendar.  Their revolution of 1918 changed all that, ushering in the “new” Gregorian calendar.  It is ironic that the revolution with all its secular overtones would abandon the secular Julian calendar for a calendar initiated by a religious system.  Spain and Italy as it turned out accepted the new calendar within 2 years.    France came on board sometime later as there was a lot of trouble with the University of Paris where the theologians resisted the idea.  Their belief system held that the church was perfect and correct in all things, including the old calendar, always supported by the church.  To them it was an admission that the church had been wrong.  It would be interesting indeed to know in detail the debates that ensued, and how resolution of their faith system finally occurred.  The group for which perhaps we should feel the most sympathy, however, was the Spanish army of Flanders.  They had ten days of their pay stopped to compensate for the time lost in the new calendar.  Amazingly the transfer took place almost immediately in China, where the Jesuit missionaries won approval of the new calendar from the imperial observatory in Beijing.

 As one might expect things did not go as well in Protestant Europe.  It was not until 1699 that Germany took up the new calendar.  This was not without considerable difficulty as many of the population observed religious holidays in accordance with the old calendar.  As Elector Maximillian I gained more power in support of the Pope, many Germans were sent to prison for non-observance of the new calendar.  The Anglican Church in England, the Calvinists in Switzerland and the Netherlands, the Lutherans in Scandinavia and Germany considered the new calendar to be diabolical.  Imagine, if you can, how it could have been, that something as inert as time became demonic!  England didn’t accept the new calendar until 1752, 169 years after its introduction.  The world looks back on the resistance of the Copernican and Galilean scientific insight by the church institution as an example of unacceptable intolerance.  But when the same church introduces something as neutral as calendrical reform, it is met with unmitigated hostility.  Robert Mandrow comments that the introduction of the modern calendrical system was “a fine example of the subordination of scientific work to the dogmatic requirement of institutional systems”. ^15.

 We turn now from the broad calendrical measurement of time to the shorter divisions of the day.  The division of the day into 24 hours is possibly related to ancient people measuring the height of the sun in the sky by holding their hand outstretched in front of their faces and marking off the number of spans.  It turns out that there are 24 spans in a complete day.    There is conflicting information as to how 60 divided the hours and minutes.  The division by 60 dates from the Babylonians who attributed mystical significance to this number.  They used the sexsgisimal system of numbers, based on multiples of sixty.  But at this point the scent of origin becomes weak as their use of the number sixty seems to have nothing to do with astronomy or the movement of heavenly bodies.

 The detail of development of time keeping, in the shorter segments, is colorful and fascinating.  We will dip briefly into a few of the major developments.   Candles were used throughout history but had serious problems with non-uniform burning rates.  An improvement was the water clock.  These were basically a container filled with water with a small opening in the bottom.  The oldest one so far, was found in the Egyptian tomb of Amenhotep I, from about 1500 BC.  These had great inaccuracies as well as you can imagine because of deposits occluding or narrowing the opening. 

 Undoubtedly the most magnificent and accurate water clock ever made was by Su Sung in China.   Magnificent because of its size and accurate because it incorporated a water driven escapement mechanism.  He built this device in 1088 AD based on water driven escapements invented about 725 AD long before anything approaching an escapement came out in the western world.  It was housed in a pagoda-like tower, measuring 30-40 feet in height.  The now published details show it was very complicated, with many revolving parts and a succession of gear trains.  The escapement mechanism, hitherto regarded as an exclusive European invention, rotated 100 times every 24 hours.  This water driven clock had a highly sophisticated ingenious arrangement for tripping the scoops into which the water flowed ensuring a uniform pressure in the water system itself.  The mechanism included a bronze power-driven armillary sphere, an automatically rotating celestial globe, and five panels with doors that opened permitting a look at the changing manikins which rang bells or gongs, and held tablets indicting the hour or other special times of the day. 

 This elaborate clock was not the whim of an inventive genius, but rather to take care of an especially intimate need for the Emperor himself.  Every night as the Emperor consorted in his bedchamber he had to know the movements and positions of the constellations at every hour – in precisely the way Su Sung’s Heavenly Clockwork made possible.  In China the ages of individuals and their astrological destinies were calculated not form the hour of birth but from the hour of conception.

 “When Su Sung constructed his imperial clock, the emperor had as attendants a large number of wives and concubines of various ranks.  These women totaled 121 (one-third of 365, to the nearest round number), including one empress, three consorts, nine spouses, twenty-seven concubines, and eighty-one assistant concubines. 

Their rotation of duty, as described in the Record of Rites of the Chou dynasty, was as follows:   The lower ranking women came first, the higher-ranking came last.  The assistant concubines, eighty-one in number, share the imperial couch nine nights in groups of nine.    The concubines, twenty-seven in number, are allotted three nights in groups of nine.  The nine spouses and the three consorts are allotted one night to each group and empress also alone one night.  On the fifteenth day of every month the sequence is complete, after which it repeats it reverse order.    By this arrangement, the women of highest rank would lie with the Emperor on the nights nearest to the full moon, when the Yin, or female, influence would be most potent, and so best able to match to potent Yang, or male force of the Son Heaven.  So timely a combination, it was believed, would assure the strongest virtues in the children when conceived.  The main function of the women of lower ranks was to nourish the Emperor’s Yang with their Yin.”

 But that was not all.   A corps of secretarial ladies kept the records of the Emperors’ cohabitation with their brush dipped in imperial vermilion.   The proper order of these proceedings in the imperial bedchamber was believed essential to the larger order and well-being of the empire.  During Su Sung’s time it was lamented that in earlier years, particularly during the disorderly days of the ninth century, that the ancient tradition of “nine ordinary companions every night, and empress for two night at the time of the full moon was no longer respected, with the result that all the three thousand palace women were in complete confusion.”  

 The need for an accurate clock, to show the position of the heavenly bodies at each moment of the day or night, was then obvious, to ensure the best-qualified succession of emperors.  The ruling houses of China did not follow the rule of primogeniture.  In theory, only the sons of the empress could become emperor, but this usually left the emperor with a number of young princes from whom to choose his heir.  A prudent emperor was bound to give close attention to the astrological omens at the precise moment when each prince was conceived.  To record these facts accurately was the duty of the secretarial ladies with their vermilion brushes.  The astronomical observations and mechanical calculations of Su Sung’s Heavenly Clockwork provided that data for these records and prognostications, and so were of great political significance.^{16. 17. 18. 19.} 

 Although Su Sung’s gear driven water clock is probably the oldest large escapement clock, the oldest gear driven clock work goes to the Greeks about 1000 year earlier.   This is known as the Antikythera mechanism found in 200 feet of water in a shipwreck off the Greek island Antikythera.  The positions of the stopped gears and dating of the associated artifacts in the ship, date the ship’s sinking to 80 BC.  Its mechanism is like a modern analogue computer which uses mechanical parts to save tedious calculations dealing with astronomical events – truly a monument to Greek science.  There are inscriptions recording “76 years, 19 years” This refers to the well-known Calippic cycle of 76 years, which is four times the Metonic cycle of 19 years, or 235 synodic (lunar) months. (These cycles deal with the problem of synchronizing the lunar cycles with the solar cycle as mentioned earlier.)  The next line includes the number “223” which refers to the eclipse cycle of 223 lunar months.”^20..

 Turning our attention now to Western Europe, we find sketchy references to Monk Gerbert who became Pope Sylvester II, inventing the first mechanical clock in 996.   There is good documentation of large mechanical clocks beginning to appear in the early 14^th century in several Italian cities.  Unfortunately no models or records of earlier clocks exist.  They were subject to inaccuracies similar to water clocks as the rate of speed was dependent on the driving weight and amount of friction in the drive.   Only two clocks of that century remain in working order to this day. One is the great clock in Strasbourg France built in 1352 and the other in Salisbury England built in 1386.

 The next advance was spring driven clocks invented between 1503 and 1510 by Peter Henlein.   They only had an hour hand.  It wasn’t until 1577 that the first minute hand was put in place for the great astronomer, Tycho Brahe, in order to track the stars more accurately.  Minute hands did not commonly appear until the 1670.  There was no glass in front of the hands until the 17^th century.  Reasonably accurate clocks had to await the pendulum.  It was Galileo who conceptually invented the pendulum clock in 1592, but it was not actually put into a clock until 1656 by Christian Huygens.  Huygens’ clocks eventually achieved an accuracy of less than 10 seconds/day.  In 1721 George Graham improved pendulum accuracy to 1 sec/day by devising a pendulum that was insensitive to an increase in length by temperature.  He then financed John Harrison’s development of a marine chronometer to an accuracy of 1/5 of one second per day capable of determining longitude to within ½ of a degree after a voyage to the West Indies.  He collected the British government’s prize for this invention -- a reward equivalent to over $2,000,000 dollars in today’s money.^{21. 22.}

 At this point I would like you to recall my previous Fortnightly paper on Nathaniel Bowditch.   One of his major contributions was a means of determining longitude at sea by use of lunar observations.^23.  Actually by the time he died, John Harrison’s chronometer was invented. There was a major problem, however, with these clocks.  Very few shipping companies could afford them, as their cost exceeded the cost of several ships.  So “shooting the moon” overlapped the chronometer for several decades in the determination of longitude. 

 During this period, the compulsion of accurate time keeping became more and more acute.   By the late eighteenth century the word “punctuality” appears in our language to describe the habit of being in good time.   Clocks became master of daily life.  By 1760 when Laurence Sterne wrote his mock-heroic Life and Opinions of Tristram Shandy, he opened his saga with the most modern possible interruption of his conception.  At the crucial moment, when Tristram’s mother and father were in bed and Tristram was about to be conceived – this is recorded:  “Pray, my dear,’ quoth my mother, “have you not forgot to wind up the clock?” “Good God!” cried my father.  “Did ever woman, since the creation of the world, interrupt a man with such a silly question?”^24. 

 By 1889 pendulum clocks achieved an accuracy of 1/100 sec/day and became the standard time keepers in observatories.  One of the most famous was the W. H. Sort clock developed in 1921 that had two pendulums. – one was a slave and the other the master.   The quartz clock came next, between 1930 and 1940.  These clocks were more accurate than the pendulum clocks and could be worn as a watch on the wrist, but there was a drawback.  The oscillation frequency of the quartz crystal depends critically on the shape and size of the crystal, which is technically difficult to control.  Thus it is not possible to have consistency from one clock to another.

 Tuning forks need to be mentioned for historical completeness, but received only a short period of popularity. 

 The next major breakthrough came with the invention of the atomic clock of which the cesium clock is the most popular.  It has gone through 7 levels of improvement reaching, in 1999, the ability of neither gaining nor loosing a second in 20 million years!  But even before this accuracy was achieved the cesium atomic clock had redefined the second.    This was in 1968 when the second, previously defined in terms of the earth’s rotation was redefined as 9,192,631,770 cycles/second of the cesium atom.  Before this change in 1968 our time was referred to earth time beginning at the Greenwich meridian in England, known as Greenwich Mean Time (GMT).  This was used as the means of determining longitude through out the world.  But with the precision of atomic clocks the problem of coordinating earth time with the new definition of the second became highly unsatisfactory.    This was because the rotation motion of the earth fluctuates by a few thousandth of a second per day.  A compromise time scale was eventually devised, and on January 1, 1972 the new Coordinated Universal Time (UTC) became effective.  This time runs at the rate of cesium clocks.  The earth’s rotation, however, is not only erratic but has a mean rotational difference.  When the difference between atomic time and earth’s rotational time approaches one second, a one-second adjustment  (a “leap second”) is made in UTC, thereby maintaining synchronization.  So the compromise is that earth retains its primacy for date-time, while actual elapsed time (laboratory time) is demarcated by the cesium atomic clock.     As miraculous as this accuracy is, the Jet Propulsion Laboratory, right next to us in Pasadena, is working on a mercury atomic clock which when operated in an orbiting satellite in 2005 will have only one second variation in 300 million years.  Hard on the heals of this advance, follows the rubidium clock that promises to provide an unimaginable accuracy of one-second in three billion years! ^25.

 With accuracies of this magnitude you would think that additional precision would come to an end, but don’t count on it.  “While time itself remains a poorly understood phenomenon, the measure of techno-scientific sophistication of various civilizations can be seen to correlate with their achievement in time measuring technologies.  How a society measures time reflects a juncture of its needs, goals, and the current level of technical achievement.  Time measurement technology is a cluster technology that sits toward the center of other techno-scientific activity.   It permits the building of complex activity interactions between people, their environment, and Nature.    Consequently, measuring time with increasing accuracy, in smaller increment, and in varying contexts has been the predominating theme for innovation.”^26.  

During the days of the quartz clock, scientists found variations of rate of spin of the earth.   This is attributed to such things as wind friction against the earth’s surface, the deposition of water as ice and snow at higher latitudes and altitudes in winter, and the tidal pull of the moon. Not only do these factors vary the rate of the earth’s spin, but also cause the spin to be slowly slowing down. The rate of slowing is 1 second in 500 years.  It has also been found that the distance between the moon and the earth increases by 4 cm each year.  This combination of features will eventually lead to synchronous rotation.  At that time the moon will constantly remain over a fixed point on the earth’s surface.  This situation already exists in our solar system between the planet Pluto and its satellite Charon. ^27.

 We are all familiar with the four time zones that divide the United States.  There are 24 around the entire circumference of the world.   These are based on 15 degree segments measured at the equator.   The historical explanation of time zones lies with the railroads in the United States.  Until a train could travel hundreds of miles in a single day there was no real problem.  But time changes about one minute for every 12 ½ miles traveled east or west.  Each major city had its own local time.  This created major problems with the railroad trying to coordinate over 300 local times.  A partial solution came with the establishment of 100 time zones by 1883.  This was still too complex for people and goods moving at increasing speeds.    So in the year 1883 the United States divided itself into 4 time zones centered on the 75^th, 90^th, 105^th, and the 120^th meridians.   Then at noon on Nov 18, 1883, telegraph lines transmitted GMT to the cities within each zone.  The authorities of the cities within each zone adjusted all their clocks to the same time.  The next year on November 1, 1884, the International Meridian Conference met in Washington DC and applied the same procedure all around the world.^28. 

 After all the trouble humans have had with this time-thing it is incongruous that serious modern physicists and astrophysicists have come up with sound reasons why there is no such thing as time.^29.  So it seems we have come full circle.  The ancient’s intense study of the heavens to come up with ways to measure time and develop various calendars, is abandoned by use of cesium, mercury and rubidium.  Then, of all things, we find ourselves in 2003, told there is no such thing as time!  I don’t know where all this is taking us, but I for one am concerned about the 50 inches of time definitions that Webster has giving us.

 Duke Ellington, Jazz pianist, composer and conductor who died in 1974 was in agreement with this modern thought when he told us he didn’t need time.  I think he had it right when he said, “I don’t need time.   What I need is a dead line.” 

 BIOGRAPHY

:  The author is a full time Pathologist and medical director of the Department of Pathology at Redlands Community Hospital.  He has been with the hospital and lived in Redlands for the past 38 years.  His hobbies are Astronomy, Amateur Radio, Sailing, Travel, Reading, and Grandchildren. 

BIBLIOGRAPHY

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