Customer Reviews

Timepieces: Masterpieces of Chronometry

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The book begins by briefly telling how units of time more precise than the day were introduced. It takes some thought to think of breaking up time into units of hours. Christianson writes that the length of an hour originally varied with the time of year (p. 8). If the day is broken into 12 hours then in the summer an hour will be longer than an hour in the winter.

The first chapter of the book is about the the use of timekeepers for regulating when monks prayed. On pp. 21-22 Christianson describes the important verge and foliot clock which was used to ring a bell at certain times to wake the monks for prayer. I'm suspicious of his claim that "during the Middle Ages time was the only aspect of science that moved ahead" (p. 25), but I do agree that medieval Europe was surprisingly more advanced than Rome at timekeeping. For the history of science and technology clocks are very important, and it seems like the spread of clocks led to a diffusion of technical skill that is probably important in European history. I believe that David Landes deals with the importance of clocks in European history in his book "Revolution in Time".

I hadn't read anything about craft guilds before and thus I found Chapter 4 on the guild system for clockmaking especially enjoyable.

The photographs and pictures in the book are good, and the diagrams are also good, e.g. verge and foliot (p. 22), escapements (pp. 32-33), the stackfreed and fusée (p. 36), cylinder and detached level escapements (pp. 80-81), and multiple views of the movement of a watch with a detached lever escapement (p. 93).

Jean-Antoine Lépine introduced in 1770 a thinner pocket watch (p. 53). Before Lépine, pocket watches had several stacks. Compare to the "oignon watch" on p. 69. Christianson explains that it was possible to have thinner pocket watches because of the "simpler small-cylinder escapement that allowed this arrangement," and also "better mainspring metallurgy that permitted longer, thinner and more flexible springs to drive the watch."

This is a book for casual reading, not a reference book. It would make a good coffee table book, since it is printed on high quality pages and it has good photos and diagrams. One can read a few pages of the book and come away with something. Examples of special topics explained in the sidebars: "Clockwork gearing" (p. 23), "Lépine and the modern watch" (p. 53), "The bored-ruby jewel" (p. 70), and "How the mechanical watch works" (pp. 152-153).

"The oscillator and escapement are the heart of the clock. The more consistent or stable the oscillations are and the more efficient the escapement is, the more accurate is the clock." (p. 32)

This book is a resume of what is written on the brilliant book of David Landes, Revolution in Time. It has a huge amount of photos, and worths every peny paid.
The book, as mentioned by the reader above, does not cover American Watches history in depth. Even tought, is a very good book.