Customer Reviews

Calendar: Humanity's Epic Struggle to Determine a True and Accurate Year

5 star:		(18)
4 star:		(11)
3 star:		(6)
2 star:		(10)
1 star:		(0)

 

 

Although ostensibly about a very narrow subject, David Ewing Duncan's Calendar: Humanity's Epic Struggle to Determine a True and Accurate Year tells a much broader story. This fine book combines both intellectual and social history with science, with the ultimate issue being "how do we define and measure a year." This is not a simple question scientifically, and the input of religion makes it more difficult still. For example, the most holy of days for Christians is Easter, yet the formula used to determine Easter was based, in part, on the spring equinox. The calendar in use before Pope Gregory was not quite accurate, with the result that Easter in the sixteenth century was being celebrated, according to astronomers, ten days "off." Science and religion have never been particularly comfortable bedfellows (one only needs to recall Galileo), so any "reform" was not as simple as it might seem. Duncan tells an excellent story, and what he does best is place in full context the seemingly narrow question of how we set the year. Although seemingly about a narrow subject, this is a wide-ranging and insightful work of history, ably written.

I agree with all of the criticisms by previous reviewers -- there are some easily caught errors (which speaks to poor editing as much as anything) and some goofy narrative speculation (not only the reindeer-clad moon-watching Cro-Magnon but also the weary Roman foot soldier). I started the book several times and, confronting these weaknesses, put it down again. But I always wound up going back because the subject is so interesting, and did eventually finish the book.

Having acknowledged the faults, though, I must say that I learned a lot reading this book, which is filled with interesting anecdotes as well as respectful nods to the many people who contributed to the development of our present-day calendar. The author does a good job of balancing specific information with the big picture, and one learns quite a bit about the history of Europe and the Catholic Church (and other areas and institutions to a lesser extent).

There is a good index.

I have to agree with oestens and would like "reader from Seattle" to explain further (see below) on how the chart at the beginning of the book can have 2000 AD as 1997 AD (I have the paperback copy - maybe hardcover has it different). The chart reads "The Year 2000 will be:" and considering that Duncun published the book in 1998 AD and used the future tense, it is clear that he meant the year 2000 AD by the current Gregorian calendar. The full sentence reads "The year 2000 will be 1997 according to Christ's actual birth circa 4 BC." That implies that we must shift the calendar BACK 3 or 4 years and renumber 4 BC as 1 AD. Then counting 2003 years from the renumbered 1 AD and we have the year 2003 AD, NOT 1997 AD. Furthermore, the rest of the dates make sense using this logic; only the Christian Era calculation does not (example: Egyptian calendar founded 4236 BC - 4236 plus 2000 equals 6236). Perhaps Duncan meant to say "1997 AD was the actual year 2000 according to Christ's actual birth circa 4 BC."

I read this not long after it was first published, so I can only speak to my general recollections. If you're looking for a Michael Crichton or Stephen King page-turner, then click on... And, after reading some of the negative reviews here, I also remember that some of the computations in this book don't quite check out. I also remember that some "tangents" to the basic story seemed to be unduly drawn out, in an apparent effort to make a book of "respectable length" (about 250 pages, in my hardbound edition). On the other hand, I think most academically inclined people would enjoy this book.

In a world where time can be measured to an accuracy of "one second in 1,400,000 years" (tycho.usno.navy.mil/cesium.html), and the rotation of the earth is no longer used as the basis for its measurement (it's not sufficiently constant), and anyone with an Internet connection can easily synchronize his PC to within .2 seconds of the correct time, it is very easy to take this whole subject very much for granted. However, if asked how long it takes the earth to make one orbit of the sun, most people would answer "one year"... and they would be wrong; it takes about 1 year and 20 minutes for the earth to orbit the sun.

There are answers to many questions (that most people probably never ask themselves) in this book. If "decem" is Latin for "ten" (thus the words decimal, decade, etc.), then why is December the 12th month of the year? There are also surprises for even the generally well educated: the Gregorian calendar "of 1582" wasn't accepted in England and America until 1752.

This book is a must read for anyone who enjoys quarky history books. Not only is it an excellent source for learning all about the calendar, but it follows the maintenence of the calendar all through the dark ages and it sheds a lot of light on the dark ages. The reasons for why are calendar is what it is today is facinating history and Duncan presents it in a way that captures the reader.

Calendar's Days & Months:
As a kid I was fascinated by my dad's Q & A! He recounted how the Calendar of the Coptic Church preserved the Alexandrine version of the accurate ancient Egyptian one. Why are the ninth to twelfth months of the year were numbered seventh (Sept) to tenth (Deci), and how consecutive 31 days July and August were jammed into the Roman calendar? Why are all the names of days after pagan gods: Sun, Moon, Ziu, Woden, Thor, Venus, and Saturn? I used similar ways to challenge my two sons interest, but then gave them a 76 pages monograph, "The Roman origins of our calendar", by Van Loran Johnson, 1958, for more details. Now, they may offer Duncan's book to their own.

Evolution of calendar:
Ancient peoples linked their 'calendar' to recurring natural phenomena, most easily observed. Annual weather changes usually post marked the times of the year in warmer climates of the Middle East. There, the moon was used to mark time, that evolved into the lunar calendar still used by today's Moslems.
Calendars have been utilized, since their invention in Ancient Egypt, to plan its farming cycles and precisely fix the celebration of agriculture seasons and events, harvests and religious festivals. At certain precise dates in Karnak's Amun Temple sanctuary, in Luxor, the rituals performed in Amun's honor each year light enters through the ceiling granite blocks during the Festival of Opet. Our contemporary calendar is one of the great adoptions by the Roman Empire from eternal Egypt. It has been in use there, in its final form for two centuries, since its reform in 238 B. C. by Ptolemy III, before it was presented by Sosigenes, an Alexandrian astronomer and mathematician, to Caesar. Cleopatra's learned courtier convincingly worked the embracement of the Egyptian calendar, renamed after Julius Caesar and stayed unchanged for over sixteen centuries, with one major improvement when it was adjusted by a Briton Monk during rein of Pope Gregory XIII, in 1582.

Western world calendar:
The history of the present western world calendar has recently been made the concern of scholarly monographs, since "Origins of time measurement and the origins of our calendar," was addressed by James Henry Breasted in 1936.
A fairly good informal history of the Western calendar, has been revisited in the dawn of Y2K by E. G. Richards, Mapping Time : The Calendar and Its History, and Michael Judge in his The Dance of Time: The Origins of the Calendar. History and FAQ's of calendars, from ancient Rome to outer space, including Julian, Gregorian, Jewish, Islamic, etc. are posted in the hyperspace from Caesar's imposition of the Julian calendar, through the medieval centuries. Various scholars noted problems but failed to repair them, finally ending with the council that promulgated the Gregorian calendar.

Duncan Calendar History:
Duncan gives a compelling and detailed discussion of the calendar history from the early development of astronomy and ancient time keeping devices, like sun dials, to the development of our modern-day calendar. He traces the development of our modern days calendar and describes how the conception of time influenced the human experience. After recounting the slow evolution of the calendar through the centuries, Duncan postulates that the real concern with time was born when a man decided to mark off the days of the lunar cycle on an eagle's bone. He tells us, in his diverse research that goes into considerable details, a story surely enjoyed by curious readers.
Duncan epilogued his account with a chapter on atomic clocks, but the wonder stays focused on those midieval centuries since the Council of Nicaea has decreed that Alexandria was to set the dates for Easter for the whole empire, and when Dante joined Copernicius in adjusting Ptolomy's year deducting some seven minutes. This fascinating book packs together diverse information on the calendar in a story that would amuse more, if some distractions are to be filtered off.

Perhaps for many people the thought of reading about time and how it is measured doesn't have quite the attraction it did a year ago with the Millenium bug looming before us. But David Ewing Duncan's book is great fun and well worth a look in.

This book is about the tricky old problem all calendar makers have been posed with in the past - which is our solar and Lunar cycles are quite different, and neither of them are quite handy enough to fit into each well without there being odd days, minutes and seconds left over. This has meant that a variety of ways of making calendars have developed.

This book is more than just a look at our Western calendar though- it is an interesting historical and cultural look at how we measure time. From simple agricultural calendars, to more complex early South American ones - and the odd ones such as the French Revolutionary Calendar which sprung up at the end of the eighteenth century. How each of them developed, the elements which influenced them and their development through time.

It is a fascinating, gutsy but quick read which draws all the elements together which make our calendars today.

This book is an engaging and informative survey of a potentially dry topic. The author makes most of the historical figures come alive, and his take on the religious and philosophical problems involved in reforming the calendar is essentially sound. But he really has no computational skills to speak of--and that's a very strange liability in a subject area like this! Almost every time he has to calculate something, he gets it wrong. (And his editor was obviously asleep and just as out to lunch on math as the author.)To cite just one huge error: Toward the end of the book he tries to get cute and give the number of oscillations of cesium that would occur in a 15-minute segment. So what does he do? He takes the number of oscillations in 1 year and MULTIPLIES it by the number of 15-minute segments in a year!(We don't see him do this math, but that's the only way he could have gotten a much huger number than he started out with.)The whole book is an argument for back to basics in U.S. schools.

This is a great reference for general readers. As other reviews suggest, specialists can pick nits; mathematicians will know more math than the author presents, astronomers more astronomy, and historians more history. The rest of us will get as much of them as we want, explained understandably. A fascinating book.

This is a so-so account of man's attempt to map time. On the plus side, Calendar gives you a good and broad account of the main developments throughout the last 2500 years. It's a bit cheesy in places and really only deals with events surronding the development of the Julian and Gregorian calendars. But it's not bad as a first attempt at the story. `Marking Time: The Epic Quest to Invent the Perfect Calendar' by astronomer Duncan Steel is much better though.

On the negative side, it's far too long and lacks credibility when dealing with numbers, astronomy and almost anything technical. Imagine a book written by an author who can't work out that if Jesus of Nazarath was born in 4BC, and there is no year zero dividing the BC and AD eras, then the year 2000 is actually 2004 and the new millenium began on 1st January 1997. If he's claiming that 1997 was really 2000, then he's also wrong. That honour went to 1996.

Just run an excel spreadsheet. Begin column 1 with -4 and then column 2 with 1 (omitting the zero between-1 and +1 in column 1). Run them side-by-side up to 2004. You'll get the answer in a flash. Why couldn't DED or his editor(s) have done this? It's very easy. In any case, there is still considerable doubt about the actual date of Christ's birth - with estimates ranging from 7BC to 3BC.

Also, its explanation of the Easter Computus just doesn't work. Nor does it explain why the calculation doesn't use the actual full moon, but uses ecclesiastical time instead - since this means that Passover and Easter (almost) never coincide. It's account of the failings of the Atomic Clock are sheer nonsense. And there is nothing to show the reader why the Gregorian calendar was designed to reflect the time between successive vernal equinoxes.

There are some bits I did like about Calendar. There easy bits on the development of the Julian calendar, placement mathematics in Arabia and India and then the decimal system involving the first use of the concept of zero. These chapters are quite good since it was mathematical developments that proved pivotal in increasing the accuracy of calendars.

This was also the first time I read about the confusion that reigned after the Gregorian calendar was adopted in the mid-16th century. Only Catholic countries obeyed the Pope's orders. Protestant states eventually joined in (mostly for economic reasons), but at different times over the next 250 years. The result was total confusion in Europe and it's colonial territories. I also now understand why the United Kingdom's tax year begins on seemingly bizarre date of 6th April - a throw back to the Julian calendar, the old New Year and the usual religious jiggery-pokery.

Overall, not bad. ...