Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time [Englisch] [Taschenbuch]

Nevertheless, I find two great mysteries or enigmas in the story written by Ms. Sobel. I presume there must be reasons for them but I am unable to guess or find them.

FIRST MYSTERY. In page 37 of the Paperback edition one can read that "Timing the motion of the lamp by his own pulse, Galileo saw that the length of a pendulum determines its rate." This is true, but it is NOT what Galileo found. That the length and rate of the pendulum are related is very old knowledge, maybe from prehistoric times. What Galileo found, by his own pulse, was that the rate of the pendulum does not depend on the amplitude of oscillation. This property is known, since Galileo, as the property of "isochronism" (having equal duration). The period of the pendulum is the same for small or large amplitudes of oscillation. I do not know why Ms. Sobel omitted this. information.

SECOND MYSTERY. In page 95 of the Paperback edition one reads about Bradley that "his efforts with a telescope twenty-four feet long provided the first hard evidence that the Earth really did move through space." This is, of course, absolutely true. But this finding by Bradley is better known in the history of science as his discovery of the "aberration of starlight" (1728). In fact, the astronomer Bradley and the word "aberration" are practically synonyms in the history of science. I wonder why Ms. Sobel did not mention this fact. This is the second mystery.

Maybe there are other enigmas; anyhow, the book is very good!

By 1730, the world still did not have any practical and reliable method of finding longitude. By 1760, it had two. One of them, backed by Britain's the most influential astronomers of the time, included a quadrant (later sextant) and tabulated ephemerides. With them, a skilled navigator could have calculated its position within hours, in clear weather. The other method required only an accurate clock. If the clock can tell you your home time, you only need to determine your local noon -- when the shadows are the shortest -- and the difference between the two tells you your longitude. This method was backed by a lone clockmaker, John Harrison. This book is about him, about his life-long pursuit of a reliable, seaworthy chronometer, and his battle with the scientific establishment.

Eighteen-century mechanics, while far from trivial, is intuitive enough to make explaination of the internal workings of a shiny brass clockwork a wonderful topic. With some diagrams and explanations of Harrison's ingenious inventions, this book could easy become any engineer's dream. Perhaps the illustrated edition (ISBN 0802713440) comes closer to this ideal. Ms. Sobel, although allegedly a science writer, was more interested in the socio-political aspects of the story, and hardly touches the engineering part. Deliberately neglecting the engineering audience, the book is far from being a historical scholarly text either. She writes in an easy-to-read, journalese style. Fair enough, some thirty references are listed in the end for anyone willing to pursue the topic further. So while you cannot claim you've learned a lot of science or history, Longitude still makes a great beach reading. And of course, reading this book is a must for anyone planning to visit the Royal Observatory at Greenwich, England, where the clocks are exhibited.

Not surprisingly, John Harrison learned that there was political finagling to contend with back then, as there is now. So his prize for solving the problem of keeping accurate time on ships wasn't as forthcoming as it should have been.

Fans of O'Brian's Aubrey/Maturin series will love "Longitude", and rejoice that the invention came along before Aubrey and Maturin's voyages. Those two encountered enough slings and arrows without having to wonder where in the world they were.

That old saw that claims "You can't tell a book . . ." is off the mark in this case. The designer of the jacket of Sobel's treasure was smack dab in harmony with the book.