It is difficult to believe that before 1851 there was no actual proof that the earth rotated on its axis. It was well accepted among scientists and mathematicians that this was the case, but no one had devised an equation or a practical demonstration of the earth's rotation.

Jean Bernard Léon Foucault was born in Paris September 18, 1819 into a comfortable middle-class family. He was not a good student and had to be tutored for a good part of his education. But as a young teenager he discovered he liked to work with his hands and use various tools to make toys. He worked with precision and took pride in his craftsmanship.

The period from 1820 to 1880 was considered to be the heyday of science, so the time was ripe for the appearance of someone like Foucault who had an engineer's mind and a mechanic's hands.

In 1839 he enrolled in medical school with the intention of becoming a surgeon, but unfortunately the sight of blood made him ill and he had to drop out.

Before leaving medical school he discovered the photographic work of Louis-Jacques Daguerre who had given a public demonstration on the Quai D'Orsay in Paris. Foucault was enthralled and studied the processes, conducting experiments with a friend. They discovered a way to improve and shorten the exposure time. Eventually Foucault used what he knew of daguerreotypy to invent a way to make photographic images of objects seen through a microscope. With the application of electricity, this process was improved and simplified even more.

By the time Foucault was 25, he had created arc lighting for the stage. At about this time he inherited from his mentor the job of science editor for the Journal des Débats. This required him to report on meetings of the Academy of Sciences. Although he came to know the members of the academy, they did not take him seriously because he did not have the appropriate academic credentials. As time went on, Foucault continued to tinker in his basement. He gained some recognition from his work on determining the speed of light but still was ignored by the Academy.

Foucault began playing with a pendulum because he knew that one had been used in measuring the location of the Paris meridian earlier in the century. As one idea leads to another, he came up with a mechanism for suspending a pendulum in such a way as to prove the rotation of the earth.

Because of his work as a science reporter, Foucault knew the director of the Paris Observatory and gained permission to demonstrate his pendulum there. The entire scientific establishment was invited to "come see the world turn," which took place on February 3, 1851.

Now, it so happened that Louis-Napoléon, President of the Republic, had a deep interest in science, to the extent that he was an avid reader of the Proceedings of the Academy of Sciences. Thus he became aware of the demonstration that Foucault had produced at the Paris Observatory. He was so captivated by the idea of what had taken place that he decreed that the experiment be repeated at the Panthéon, which had the highest dome in Paris.

It also happened that the Academy was completely embarrassed by Foucault's accomplishment. All of the great scientists with their vaunted degrees from prestigious universities had just been one-upped by a man with no credentials at all, but an intuitive mind and an ability to make things happen. The resentment this caused kept Foucault out of the Academy until the honor was bestowed upon him by Louis-Napoleon many years later.

Amir Aczel has presented a very interesting story of Foucault in the scientific, mathematical, political and social context of the day. He is a good storyteller, and it is a good thing because there are many digressions which explain the scientific background of Foucault's various projects. ( )

I have a weakness for books that teach me stuff. No matter that I can learn the book's "stuff" in 10 minutes using Wikipedia... it's always nice when someone can take an 800-word encyclopedia entry and spin in into a 180-page story.

Call it the human element, if you would. This book has it, in spades.

I more or less knew who Leon Foucault was before I read this book, but the author assumes you don't and gives you a gentle, well-crafted overview of Foucault's life and work. The episode on the eponymous pendulum is the piece-de-resistance, but I was likewise fascinated by Foucault's other scientific successes, some of which were way, way before his time. The author persuades you that Foucault was a misunderstood genius of the first order, and overcame his humble background and lack of formal training to make great contributions to science, and as such, adds much human depth and interest to what might have been a much flatter biography.

The science of Foucault does not get short shrift here, even though the book is aimed at the layman. Some rather gnarly equations are given as proof of one of Foucault's theorems, but mercifully, they are relegated to the end of the book.

All in all, a very enjoyable read, one I would recommend without reservations to people who enjoy biographies, history of science, or both. I probably won't be reading it again. ( )

A quick biography of Foucault and his eponymous pendulum, as well as his royal benefactor, Napoleon III. About once a century, the crazy amateur scientist challenging the established scientific thought is actually correct. Foucault is 19th century France's one. Despite being the first to prove that the Earth rotates on its axis with not one but two simple, elegant experiments (the other is the gyroscope), the French scientific community refused to accept the self-taught Foucault as a member of the French scientific community until a royal decree by the scientifically minded emperor Napoleon III placed him in the French Academy of Sciences.

Aczel's short but well written account of the life of Foucault spends almost as much time on the life of Napoleon III and his rise to power, as the two's fates seem to be intertwined. A thoroughly enjoyable book. ( )