Pendulum: Leon Foucault and the Triumph of Science

by Amir D. Aczel

In 1851, struggling, self-taught physicist Léon Foucault performed a dramatic demonstration inside the Panthéon in Paris. By tracking a pendulum's path as it swung repeatedly across the interior of the large ceremonial hall, Foucault offered the first definitive proof -- before an audience that comprised the cream of Parisian society, including the future emperor, Napoleon III -- that the earth revolves on its axis.

Through careful, primary research, world-renowned author Amir Aczel has revealed the life of a gifted physicist who had almost no formal education in science, and yet managed to succeed despite the adversity he suffered at the hands of his peers. The range and breadth of Foucault's discoveries is astonishing: He gave us the modern electric compass, devised an electric microscope, invented photographic technology, and made remarkable deductions about color theory, heat waves, and the speed of light. Yet until now so little has been known about his life.

Richly detailed and evocative, Pendulum tells of the illustrious period in France during the Second Empire; of Foucault's relationship with Napoleon III, a colorful character in his own right; and -- most notably -- of the crucial triumph of science over religion.

Dr. Aczel has crafted a fascinating narrative based on the life of this most astonishing and largely unrecognized scientist, whose findings answered many age-old scientific questions and posed new ones that are still relevant today.

Genres: Science, Nonfiction, Biography, History, Physics, Popular Science, Mathematics

288 pages, Paperback

First published January 1, 2000

About the author

Amir Aczel was an Israeli-born American author of popular science and mathematics books. He was a lecturer in mathematics and history of mathematics.

He studied at the University of California, Berkeley. Getting graduating with a BA in mathematics in 1975, received a Master of Science in 1976 and several years later accomplished his Ph.D. in Statistics from the University of Oregon. He died in Nîmes, France in 2015.

Reviews

[Mark Fallon · Rating 4 out of 5]

Like many kids who grew up in Greater Boston, I was mesmerized by the pendulum at the Museum of Science. How did it work?

Amir Aczel brings to life the story behind the pendulum - and the story of the man who proved the rotation of the Earth, Leon Foucault.

[RKanimalkingdom · Rating 1 out of 5]

I'm starting to get annoyed at non-fiction books that don't get to the point at quickly.
Similar chapter structure over and over again.
By the time we got to the facts, I could not care

[Ron · Rating 4 out of 5]

Very readable account of Foucault, a self-taught scientist and mathematician, and the French scientific elite who refused to give him the recognition due to him. From Amazon: He was neither a mathematician nor a trained physicist and yet Léon Foucault always knew that a mysterious force of nature was among us. Like Newton, Galileo, Copernicus, and others before him, Foucault sensed a dramatic relationship between the rotating skies above and the seemingly motionless ground beneath our feet. But it wasn't until 1851 -- in Paris, inside the Panthéon, and in the company of fellow amateur scientist Napoleon III -- that Foucault swung a pendulum and demonstrated an extraordinary truth about the world: that it turns on its axis.
Pendulum is a fascinating journey through the mind and findings of one of the most important and lesser-known characters in the history of science. Through careful research and lively anecdotes, world-renowned author Amir D. Aczel reveals the astonishing range and breadth of Foucault's discoveries. For, in addition to offering the first unequivocal proof of Earth's rotation, Foucault gave us the modern electric compass and microscope, was a pioneer in photographic technology, and made remarkable deductions about color theory, heat waves, and the speed of light.
At its heart, Pendulum is a story about the illustrious period in France during the Second Empire; the crucial triumph of science over religion; and, most compelling, the life of a struggling, self-made man whose pursuit of knowledge continues to inform our notions about the universe today.
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[Mario · Rating 4 out of 5]

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.

[Cate · Rating 3 out of 5]

This book has a fine line to walk: on the one hand it is discussing complicated math and physics, but on the other telling the story of a man's life and accomplishments. On the whole, it succeeds, but it occasionally oversimplified the history and failed to articulate the math. I could follow the basics and understand the pendulum experiment itself, but the underlying "why does the pendulum move that way" problem was out of league...and not really of interest. The descriptions of the Second Empire and the academic in-fighting of the French scientific community were interesting, but not very detailed and sometimes told out of order. Also, the author has an almost Dan Brown-ish tendency to end chapters in the wrong place or with unnecessary cliff-hangers. However, Aczel at least does not repeat himself and strives for clarity and brevity.

[Ed Terrell · Rating 5 out of 5]

Great book and a very worthwhile read for anyone interested in how ideas develop over time. Clear, thoughtful line of thinking starting with Ptolemy's Almagest (second century AD ) through the development and demonstration of the pendulum and gyroscope. Most interesting as well is that science is not developed in a vacuum but is set in history, religion and politics (i.e. science abhors a vacuum). In this, case it was set in the upheavals of France caused by Louis-Napoleon III assumption as emperor. The cumulating pinnacle of this idea was in 1851 and in Focault's sine law which determines the length of time it takes at any latitude, for the pendulum's plane of oscillation to sweep a full circle. Science writing at its best.

[Wens Tan · Rating 2 out of 5]

Foucault’s story is a tale of a man with a raw yet penetrating insight to how nature works, and of an outsider’s battle against a conservative academic elite.

While Aczel’s book presents the facts in an orderly fashion, giving adequate context to the story, his bland style fails to turn the promising material into a gripping read.

[Cláudia · Rating 5 out of 5]

que livro espetacular! Como é bom aprender coisas novas, entender melhor o mundo. E ao mesmo tempo, é um tanto quanto chocante perceber que existem partes da história mundial das quais não temos conhecimento algum. Feliz demais em conhecer essa pequena porção da história da ciência!

[Jon Bradley · Rating 5 out of 5]

I purchased my copy of this book used in hardcover at Prospero's Books in Kansas City, MO last year. I think a lot of my enjoyment of this particular book springs from my love of Umberto Eco's book "Foucault's Pendulum," a work of fiction that begins and ends at the real-life pendulum on display in the Conservatoire des Arts et Metiers in Paris. I was so taken by Eco's book that on a visit to Paris in 2022 I made it a priority to visit the Conservatoire (now called the Musee des Arts et Metiers) to see the very same pendulum written about in Eco's book. And there on display in a glass case in the Musee was the bob from the pendulum Foucault created for the French Universal Exposition held in Paris in 1855. Now let me turn to the book actually being reviewed. Aczel's book tells the whole fascinating story of Leon Foucault, a 19th century Frenchman blessed with great mechanical aptitude and an intuitive grasp of physical principles, despite the fact that he had no formal education in any field of science. As it turns out, he invented any number of devices, including the gyroscope, but he was rejected by the French scientific community because of his lack of formal training. The books starts with a discussion of the various famous persons in history who developed competing theories and models of how the earth and planets move (or don't move) in relation to the sun: Ptolemy, Galileo, Newton, Copernicus, Kepler, etc. Today we all know (except perhaps for those flat-earth knuckleheads) that the earth rotates on its axis as it orbits the sun. I was astounded to learn that as late as the year 1851, there was still no means to directly measure and demonstrate that the earth rotates on its axis. It was a commonly accepted theory, which explained any number of astronomical observations, but there was no definitive proof. Foucault's crowning achievement was his use of a special pendulum in 1851 to demonstrate in a visible way that the earth really does rotate on its axis. The French scientific elite had to accept Foucault's findings, but they didn't have to accept the man or accord him honors until Louis-Napoleon, President of the Republic, intervened and forced them to. Later in life Foucault found a measure of respect from the French scientific community before he died at the young age of 49 from a neurological disorder. I found this book to be well-written and interesting throughout. And if you ever find yourself in Paris, the Musee des Arts et Metiers is a real gem. Five out of five stars.

[Barak · Rating 3 out of 5]

I have read before quite a lot about the history of science in the 19th century, but mainly the one taking place in Britain. This book gave me an opportunity to see it from a continental/French perspective*. The book describes this brilliant discoverer, Leon Foucault, who created a relatively simple experiment to prove/demonstrate once and for all the rotation of the earth. The author also sheds light on the historical context of the French Second Empire period under Napoleon III, a period in French history I knew little about.

* so I got for instance the story of calculating the location of the missing star (Neptune) and consequent discovery of it from Verrier's perspective rather than from that of John Couch Adams.

[Daniele Scaglione · Rating 4 out of 5]

Bellissimo resoconto della storia di una ricerca, e di un ricercatore che, alla fine, ce l'ha fatta. Un ricercatore anomalo, escluso dal gruppo dei grandi scienziati - soprattutto matematici - attivi in Francia nel XIX secolo. Léon Foucault non aveva una formazione scientifica superiore, eppure è stato capace di produrre dei risultati scientifici di primo piano, non solo dimostrando che la Terra gira in due modi diversi, ma anche misurando con gran precisione la velocità della luce e con altri risultati ancora. Aczel riporta la sua storia in un modo che mi ha appassionato, inserendola molto bene nel contesto della Francia della prima metà dell'800.

[Len Knighton · Rating 5 out of 5]

Those who have known me for many years might be surprised that I read a book about a mathematician. Indeed, the math was over my head but I found the man, Leon Foucault, and his experiments fascinating. A wonderful book; a tribute to a man who didn't receive the accolades due him until near the end of his life.

Five stars waning.

[Maciek · Rating 2 out of 5]

O ile kontekst historyczny jest istotny to te wszystkie przygody Ludiwka Napoleona były zupełnie niepotrzebne. Aczel mógłby poświęcić to miejsce na dokładniejsze opisy prac naukowych Foucaulta. Z drugiej strony, w kwestiach naukowych Aczel popełnia błędy merytoryczne (wyłapane przez tłumaczkę)...

[Jukka Häkkinen · Rating 3 out of 5]

Sujuvasti kirjoitettu Leon Foucaultin elämäkerta, joka välillä harhautuu liikaa sivupoluille.

[Gary Mcfarlane · Rating 5 out of 5]

An interesting story of Léon Foucault - especially after teaching about this in science classes many years ago and seeing the pendulum in France a few years ago.

[simorosso · Rating 1 out of 5]

peggior libro che abbia mai letto, di una noiosità assurda

[dejah_thoris · Rating 4 out of 5]

Foucault is another example of a brilliant scientist that was barely acknowledged during his lifetime because he didn't have the correct educational background. But he proved amazing results about our cosmos with elegant theories that science and mathematics couldn't refute, despite insanely complicated attempts to do so. Foucault probably would've been lost to the ages if it hadn't been for the respect of Napoleon III, who created a position for him and funded all his experiments after his breakthrough with the pendulum, proving the Second Empire wasn't all bad. Overall, a great little history of another important scientist and his accomplishments.

[AC · Rating 3 out of 5]

An excellent history of Focault, French Math/Science, and the triumph of discovery that, despite many prejudices, Focault would make and give to the world. Painting the learned Scientific society of the day as self-important egotists ready to dismiss any idea that didn't come from them, Aczel effectively demonstrates that sometimes having the right answer and the insight to get to it isn't always enough to make a scientific breakthrough.

[Lisa · Rating 3 out of 5]

I really enjoyed this book. The subject matter covered the history of Foucault's life and simple explanations of the science behind his discovery's. It was well written and the author has a knack for simplifying the complex.

He brought Mr Foucault alive for me - I envisage him as one of those people who are essentially good folk, but who are so desperate to be accepted that they put people off. I think he was just trying too hard :-)

[Stan Paulsen · Rating 4 out of 5]

Another great book by my favorite science author. Such a simple and elegant experiment to illustrate beyond doubt that the Earth's rotation caused the apparent motion of the sun, planets and stars is inspiring. At the time, many people still believed the Earth was the center of everything. A simple self taught man displayed his pendulum in the Pantheon of Paris vindicating Galileo, Copernicus etc, causing even the church to embrace the truth of scientific discovery.

[Frederick Bingham · Rating 3 out of 5]

This book lent to me by Claudia Stack.Leon Foucault invented the Foucault pendulum in the 1850's. The first real proof that the earth spins about its own axis. The author describes the invention and the man who invented it. Foucault lived in some rather turbulent times in France, the beginning of the second empire. Foucault got along well with Louis-Napoleon, the new emperor, who was an amateur scientist. The author describes some of the events spinning around Foucault as well.

[Juliana Gioria cardoso araujo · Rating 4 out of 5]

This book was very interesting and I think reading it after seen the real pendulum is just better.

It is an insight in a interesting mind though thoughts, ideas and realization of it and is one of the few those books that left me with feeling that we as humans can do anything if we put our mind to it.

It is worth to spend time reading this book that at times can be heavy and not very simple but still interesting enough to keep reading.

[CD · Rating 2 out of 5]

This book was disappointing in its attempts to illuminate the era and life of Foucault. There is lots of information available about Leon Foucault that is not presented in a consistent or even a always readable format. Needs the hand of an editor to make the book more cohesive and thus probably ultimately of more value.

[Todd Van Meter · Rating 5 out of 5]

A very interesting and enlightening detailing of the struggles and ultimate successes of Leon Foucault. His many contributions to modern science include the first definitive proof of the earth's rotation, gyroscopes, and several other mathematical proofs and scientific instruments that still affect our daily lives.

[Freshta · Rating 4 out of 5]

Interesting book. Easy to read and involves more of French history of Foucault's time than I had expected but it was helpful to understand circumstances around him better and it was good to learn more about Napoleon III's involvement with science as well as how the scientific community despised a great scientist because of....

[Tony · Rating 3 out of 5]

This is a typical book in the genre of writing about science and scientists. I felt the author was trying to find a story rather telling the actual story, but, nonetheless, the book is worth a read. Most interesting, probably, is the account of Paris during a fascinating period in its history.

[Larry · Rating 4 out of 5]

Great background on the life and times of Leon Foucault and the many factors that shaped his world. If I have a complaint, it is that there is too much on the peripheral characters and too little on Foucault himself. I could have used more detail on the pendulum experiment as well.

[Lolakay · Rating 4 out of 5]

I borrowed Pendulum for a train ride and was wowed. I'll have to look for more of Aczel's work.

[Tina · Rating 5 out of 5]

I love reading about the struggle that science has had throughout history just to point out the now obvious. Pendulum is no different.

[EdMohs · Rating 5 out of 5]

history of the pendulam
what really moves ?