Customer Reviews

Mapping Time: The Calendar and Its History

5 star:		(3)
4 star:		(1)
3 star:		(2)
2 star:		(1)
1 star:		(0)

 

 

One of several books written in anticipation of the millennium, "Mapping Time: The Calendar and Its History" by E. G. Richards suffers from an especially heavy burden of typographical errors. As can be seen on the author's own web page, the address of which also is incorrect, there are hundreds of errors, some of which affect the accuracy of the account. For example, on page 208, January 1 came to mark the beginning of the Roman civil year in 153 BC, not 158 BC, and was in response to the Second Celtiberian War in Spain. Rather than wait until the middle of March for consuls to assume office, the new year was moved to the first of January so the Roman commander could depart with his legions that much sooner. It is a pity that so many errors compromise an otherwise informative history. Until they can be corrected, a better introduction to the calendar is "The Oxford Companion to the Year."

Very interesting history of the major calendar systems used around the world, both in the present day and in the past. It also gets into the mathematics of how to convert between calendar systems, including algorithms suitable for computer programming. Unfortunately, there are numerous typographical errors in the narrative and in the algorithms! The word "temperature" where the author clearly meant "temperate", substitution of "*" for "-" in a formula, etc. So far, I have been able to correct the formula for computing the day of the week and the formula for computing the date of Easter. I'm not looking forward to tackling the other algorithms. Did anyone proofread this before it was printed? Maybe the publisher could put up an errata sheet on their web site.

Good for the history, but be prepared to do some algebra if you want to use the algorithms.

This is a nice examination of the different calendars and methods of mapping time that humans have employed over the centuries. On the surface it has the air of a dusty reference book, but inside the author is often witty and amusing as he covers the histories and backgrounds of different dating systems. I'm especially impressed by his inclusion of the different algorithms used to calculate dates, of Easter for example, which are marvelously complex. Most readers will never have occasion to use these algorithms, but its nice to know they're there. I also appreciated the charts and the glossary of the more obscure calendrical terms.

Designing calendars is one of the more difficult tasks that human beings have set themselves. You first needed to -determine- the lengths of the cycles of the solar year and the lunar month. This was not an easy task, and it was not achieved until well into recorded history.

The various cycles don't fit into each other particularly easily, either. With a solar year of just under 365.25 days, and a lunar month of just over 29.5 days, you aren't going to get it to come out even in the short run. You can stick with the sun and ignore the moon --- the solution of the Roman calendar fixed by Julius Cęsar. You can go with the moon, and leave the seasons to fall where they may --- as Muhammad, the desert-dwelling prophet of Islam, chose.

Or you can try to keep the moon and sun tied together, necessarily loosely. This requires a number of cumbersome kludges, as the Babylonians, the Jews, the Chinese, and the Christians who fixed the date of Easter all discovered. These calendars took a lot more thought than the ones that simply discarded one or the other heavenly lights, and rank among the most intricate and intriguing works of ancient astronomy.

This book contains a complete listing and description of the several solutions people have come up with to this seemingly intractable problem of arithmetic.

In this well-illustrated book, the author accurately presents lunar and solar calendars. A history of the Egyptian, Mayan, Chinese, Jewish, French Republican, Roman, prehistoric and present-day Gregorian calendars is provided. The author has also included commentaries about astronomy, writing, counting, the week, the month, the year and calendar reform. An excellent readable reference on a fascinating subject for the interested reader.

nice, documented, interesting compilation/essay on the most important topics in the study of calendars. good place to start if you are interested in the topic. apparently started as the author wanted to build algorithms to program a computer to switch between dating systems.

a few places i had to scratch my head and wonder about what he was saying, a bit more explanation in those contexts would have helped. the glossary in the back is a very good idea, i used it several dozen times. a bit more diagrams and hand holding would have improved the book for me.

makes what could be a dull and boring subject, interesting, flowing and a worthwhile read. probably a bit advanced for the average person at places, but don't get discouraged, keep reading and struggling with the material.

I do not know where to begin. I have to begin somewhere, so for starters, the biggest problem with this book is the author's pedestrian prose. The prose occasionally avoids being pedestrian, but only when it diverges into muddled and confused. There is one short paragraph in an early section on positional astronomy where the author changes his mind twice. He is not offering different points of view, he says one thing, contradicts himself and then reasserts his original view. Positional astronomy is "settled science" and has been since about the Second Century B.C. His presentation is so muddled that a reader encountering it here for the first time will be completely confused.

Pedestrian prose in the service of a grand concept is more than adequate, but this book is barely an adequate first draft. There could not have been any fact checking, there are so many distortions and misstatements of verifiable facts that it is dizzying. (One glaring example is the definition of the second prior to 1967. You can only make the sort of mistake he makes here if you are almost completely ignorant of the details of the time measurement in the 19th and early 20th Centuries.)

The author admits that he is neither an expert nor is he writing for a scholarly audience, and for that reason omits footnotes and citations. Where he avoids misstatement, he glides effortlessly into incompleteness. He treats the history of 20th Century time keeping without mentioning General Relativity or even Ephemeris Time. This would be like writing a history of Ford's Theater without mentioning the Assassination of Lincoln. If all you learn about mean solar time is from this book, you will leave knowing less than when you started.

If you think I am being overly critical, given the author's admittedly modest goals, I think the standard of comparison should be Dava Sobel's Longitude. Ms. Sobel brings a lively style and encyclopedic grasp of the facts to the same kind of effort, an attempt to explain to the non-specialist an aspect of the history of science and technology.

Why even two stars? The author is (*cough*) an intellectual tourist and is giving us a look at his personal scrapbook, however disorganized, incomplete and, shall we say, contrafactual? It is a fun journey; it's like watching a neighbor's vacation slides from a trip to the Alps, assuming your neighbor isn't a travel writer. Just don't mistake his recollections for an authoritative history of Switzerland.