Time flies - and so do the ways we keep it

MAPPING TIME: THE CALENDAR AND ITS HISTORY E.G. Richards Oxford University Press 438 pp., $35

It would save a great deal of bother if computer programmers could somehow be persuaded to use the Jewish calendar. By this reckoning, it is now the year 5757; the Y6K problem would be put off for another 2-1/2 centuries.

Almost every possible astronomical system for organizing time has been tried. "In Mapping Time," British science historian E.G. Richards describes a number of these in a wide-ranging and entertaining fashion.

The author's style is both precise and appealing, and some of the material included is downright eccentric. For example, Richards includes a section on calendar conversion schemes for the calculator or computer. These allow, should one wish, converting dates in the Mayan ceremonial calendar to Gregorian dates, and vice versa.

The author notes that the Gregorian calendar, used by most of the world today, is based on an earlier one ordered by Julius Caesar in 46 BC. Cleopatra may have introduced Caesar to the Alexandrian astronomer Sosigenes, while the Roman general was waging his Egyptian campaign. Sosigenes suggested a 365-day year, with a single extra day introduced every four years to make a leap year.

Christianity inherited the Julian calendar from the Romans. "The Christian era was invented by Dionysius Exiguus ('Dennis the little' - so called because of his self-demeaning manner)." He calculated, incorrectly as it turns out, that Jesus had been born 532 years before. In fact, the evidence suggests that the year of the nativity was 4 BC, during the reign of Herod the Great.

Also, unfortunately for Sosigenes, there are not quite exactly 365-1/4 days in a year. By the Middle Ages, the calendar had gotten more and more out of sync with the celestial events it was supposed to predict. In 1582, Pope Gregory XIII introduced the refinement used to this day, directing that century years not include Feb. 29, except when evenly divisible by 400.

The British (and the Colonies) did not adapt the Gregorian calendar until 1752. By this time, England and America were 11 days behind most of the rest of Europe. By order of King George II, Wednesday, Sept. 2 was followed by Thursday, Sept. 14.

The author argues that it was British cultural imperialism that spread the Gregorian calendar worldwide. Thus, we have the curious spectacle of the Tongans - who probably had not heard of Julius Caesar or Pope Gregory until relatively recently - inviting tourists to their South Pacific nation to be the first to greet the year 2000 as the sun crosses the international date line.

From earliest times, the calendar has served religious purposes, denoting the time of festivals and religious holidays. Indeed, two of the most notable recent efforts to change the calendar were deliberate efforts to break this ancient connection. After the French revolution, a new calendar was introduced dating from the founding of the Republic on Sept. 22, 1792. Each month was divided into three "decades" of 10 days each; the day was to be divided into 10 hours with 100 minutes per hour and 100 seconds per minute. Watchmakers were instructed to manufacture decimal clocks and watches, and the law strictly prohibited the use of the old calendar.

In our century, under Stalin the Soviet Union attempted to establish a five-day workweek; Saturday and Sunday were abolished. Everyone got one day off in five, but workweeks were staggered, so that the factories and shops would always be open. Both the French and Russian revolutionary systems were efforts to rationalize the calendar, to free it from the old constraints, and both were dismal failures.

It seems that the human fondness for the familiar outweighs the possible benefits of the new, "scientific" systems. Whether we humans create calendars that mirror our habits, or instead live out lives that are somehow affected by the choice of a calendar system, clearly there is some deep underlying connection. This intriguing and comprehensive volume offers hints as to what that might be, and much to ponder about the relationship of calendars and culture.

*Frederick Pratter is a freelance writer in Missoula, Mont.