Circumference: Eratosthenes and the Ancient Quest to Measure the Globe

by Nicholas Nicastro

How do you measure the size of the planet you’re standing on?

“Circumference" is the story of what happened when one man asked himself that very question. Nicholas Nicastro brings to life one of history's greatest experiments when an ancient Greek named Eratosthenes first accurately determined the distance around the spherical earth. In this fascinating narrative history, Nicastro takes a look at a deceptively simple but stunning achievement made by one man, millennia ago, with only the simplest of materials at his disposal. How was he able to measure the land at a time when distance was more a matter of a shrug and a guess at the time spent on a donkey’s back? How could he be so confident in the assumptions that underlay his that the earth was round and the sun so far away that its rays struck the ground in parallel lines? Was it luck or pure scientific genius? Nicastro brings readers on a trip into a long-vanished world that prefigured modernity in many ways, where neither Eratosthenes' reputation, nor the validity of his method, nor his leadership of the Great Library of Alexandria were enough to convince all his contemporaries about the dimensions of the earth. Eratosthenes' results were debated for centuries until he was ultimately vindicated almost 2000 years later, during the great voyages of exploration. “Circumference” is a compelling scientific detective story that transports readers back to a time when humans had no idea how big their world was--and the fate of a man who dared to measure the incomprehensible.

Genres: Science, History, Nonfiction, History Of Science, Greece, Geography

240 pages, Hardcover

First published January 1, 2008

About the author

Nicholas Nicastro was born in Astoria, New York in 1963. His education includes a B.A. in English from Cornell University (1985), an M.F.A. in filmmaking from New York University (1991), an M.A. in archaeology and a Ph.D in psychology from Cornell (1996 and 2003). He has also worked as a film critic, a hospital orderly, a newspaper reporter, a library archivist, a college lecturer in anthropology and psychology, an animal behaviorist, and an advertising salesman. His writings include short fiction, travel and science articles in such publications as "The New York Times", "The New York Observer", "Film Comment", and "The International Herald Tribune". His books have been published by Penguin, St. Martin's, and HarperCollins.

Reviews

[Jane · Rating 4 out of 5]

More like 3.5. Fascinating and educational for a layperson like me, but I felt it was bloated. Yes, Eratosthenes was covered--even with the sketchy information on his life from the Suda [the Byzantine encyclopedia] and what his conclusions on geodesy--shape of the earth and its circumference--were and how he reached them. The earth as a globe was only one out of several theories current at that time. It was amazing that he reached pretty accurate conclusions using only primitive surveying techniques of that time and his knowledge of geometry--no trigonometry tables back then. But the book was swollen was tangential information such as: the Hellenistic society in Alexandria of his time and its exhaustive description; the Ptolemaic dynasty; The Museum and Great Library in Alexandria; how knowledge of the ancients was lost [much through the vandalism of Christian zealots who I'd compare to the present-day Taliban or to ISIS rampaging through the ruins of Palmyra] and finally recovered, some through the Arab scholars, some on palimpsests, and some through references in other writings that have come down to us.

I feel this readable book could have been condensed into a volume half its size. Interesting to me was the fact that Columbus knew the world was round, BUT he underestimated the size of its circumference. Also interesting was the fact that his successor at the Great Library, Aristophanes of Byzantium, was the man who first developed a system of diacritics used in the Greek language; they are still used today in Modern Greek in a simpler form. The author closes with a metaphor: as the Eratosthenes Mountain Range 6000 feet undersea, Eratosthenes the man has remained obscure to us.

Recommended for popular science fans.

[Kelley · Rating 5 out of 5]

A fascinating little book about how Eratosthenes, The Librarian of the Great Library... yes THE Great Library of Alexandria calculated the circumference of the Earth in 3rd century BCE (or BC, if you prefer). Nicastro paints a detailed, but never tedious, picture of Egypt under Greek pharaohs, the impact of various philosophers and philosophies on early science, and the development of Alexandria and its Great Library itself. The author writes with a touch of humor and irony when comparing the Ancient Greeks with Western Civilization today and it becomes clear that while we may be technologically more advanced (though not as much as you might think), we are not any smarter. Or, more appropriately, they were as smart as we are. Maybe more so.

[Robert · Rating 5 out of 5]

My favorite kind of history books are those that are short and to-the-point: Describe a person, event, or object, explain where it came from, what it did - and why it is so important. DeKay's Monitor comes to mind, as does Sobel's Longitude. Nicastro's book fits neatly with these two, in explaining how Eratosthenes determined the size of the earth, a number that was hitherto, at best, a guess. Nicastro also follows in the footsteps of Bill Bryson's attempt to write a biography of Shakespeare, in that both Shakespeare and Eratosthenes left remarkably few footprints, and thus their lives must be inferred from the affect that they had on others, rather than from direct evidence.
Nicastro succeeds magnificently in both ways, writing the short, but complete, story of man's first attempt to understand how large the planet on which they stood actually was, a number that would continue to be of prime importance for the next 2000 or so years. Highly recommended for all interested in science, history - and their intersection.

[James Henderson · Rating 3 out of 5]

This is another of that group of books of which Longitude is probably the most famous example. Nicholas Nicastro explores the history of the idea of the circumference of the globe. It is a journey that starts with questions raised by an ancient Greek named Eratosthenes, about whom we learn a great deal more than his discovery of circumference, and doesn't end until almost two thousand years later. For those who love the history of science and how ideas develop it is a great read. Enjoy!

[David · Rating 2 out of 5]

A great magazine article buried in a book worth of padding.

[Johann · Rating 5 out of 5]

In this book, Nicholas Nicastro explains how Eratosthenes calculated the circumference of the globe around 240 B.C. and got an almost perfect answer, using only the earth, shade of the sun, and Greek Geometry. No one came as close to the correct measure until centuries later when scientists had access to modern tools and techniques.
In addition to the story of Eratosthenes and his achievement, Nicastro brings in many interesting subjects that beg further studies, such as the Library of Alexandria and its collection of ancient texts. The difficulty of understanding ancient scientific documents, due to a combination of language, measurements, and definitions. The problem of translation in general, when it comes to evaluating what the original author intended to say or do in certain circumstances and does not explicitly state so. Finally, in the last chapter, Nicastro points to the damages done by Christianity to science in the first few centuries C.A. The burning of the sister library in Alexandria, the mob killing of Hypatia, the ignorance and misoneist tendencies of the hordes of monks laying waste to intellectual life around the Mediterranean.
Highly recommended to all.

[Christian K · Rating 1 out of 5]

One of the worst written books I’ve ever read

[Wayne · Rating 3 out of 5]

Probably due to the scant sources available on the topic, the book covers more than just Eratosthenes and his technique for measuring the circumference of the earth. The book goes into detail about the history of Alexandria, where Eratosthenes spent the second half of his life as the director of the Great Library of Alexandria. More interestingly, in my opinion, was the latter half of the book that goes into the lineage of scientists that laid the groundwork for Eratosthenes and those that came after him. Few books go into detail about the Arabic advances on Greek science and math, which we owe for preserving the original sources. I appreciated that the Arabic advances on E were also included. The minor history of world maps were also intriguing and enjoyable.

[Rebecca · Rating 3 out of 5]

This is a very readable account of the times of Eratosthenes. It is filled with a lot of information, not just about Eratosthenes but about the times and the state of science. I sometimes don’t read the preface but this time I’m glad I did. It gave me some insight into how the author approached the topic that I thought it was useful to have. Even though I did find all the information I was reading interesting I did start to wonder when Eratosthenes was going to show up in this book but when he did it became apparent why all the information that came before was necessary. It sets the stage for the feat that Eratosthenes accomplishes. And understanding the world around him and having him firmly placed in a well-defined setting helps you to understand Eratosthenes better. You get to see how Eratosthenes went against convention and popular thought in his pursuit of science and how he was an original thinker in a lot of ways. And you see the impact of his work on those that came after him. Not much in known about Eratosthenes but Nicastro manages to give the reader a wonderful idea of who the man was and why he has been remembered through history.

[Jeff Schilling]

Circumference is as much a story of the evolution of Greek science as it is a history of discovery. The story is of a similar ilk to those of Simon Winchester (The Map That Changed the World: William Smith and the Birth of Modern Geology), [return]Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time by Dava Sobel, and The Riddle of the Compass: The Invention That Changed the World by Amir D. Aczel.[return][return]The narrative arc was not as compelling as some and may be due to the paucity of direct knowledge around Eratosthenes.[return][return]All in all, an enjoyable read, particularly if you're partial to science and the evolution of human knowledge.

[Nooilforpacifists]

Awful. Not a history of the measurement, but a vast, padded history of the history of Greece and Egypt. I quit 30% into the thing when I got to this quote about the creation of the library at Alexandria:


Displaying a philosophy in exact opposition to that of America's forty-third president, Demetrius advised the prince "to collect books on kingship and the exercise of power, and to read them."


I suppose it ever will be fashionable among the Professorship to bash W., but surely nothing could be more pointlessly out of place. (Plus, having a passing acquaintance with "America's forty-third president" -- I doubt the author ever has been within 100 miles -- I assure the author he is neither dumb nor illiterate.)

[Ioannis Savvas · Rating 3 out of 5]

Αν και το βιβλίο χαρακτηρίζεται ως ιστορικό μυθιστόρημα, δεν έχει τίποτα το μυθιστορηματικό. Πρόκειται για μια ιστορική μελέτη της εποχής του Ερατοσθένη, ενώ η αναφορά στη μέτρηση καθεαυτή της περιφέρειας της Γης είναι μικρή. Παρουσιάζονται το ιστορικό, πολιτικό, φιλοσοφικό και διανοητικό πλαίσιο στο οποίο γεννήθηκε και πραγματώθηκε αυτός ο εκπληκτικός μαθηματικός υπολογισμός, και το βιβλίο καταλήγει με τις προεκτάσεις αυτής της μέτρησης και τη σημασία της για την ανθρωπότητα. Ένα ενδιαφέρον βιβλίο.

[Jacobi · Rating 3 out of 5]

I picked this up from the library on a lark because it was face out on the bookshelf, and I'm glad I did. Eratosthenes is a figure I know absolutely nothing about, and this was a nice survey of the man's accomplishments in and contributions to science. The books also talks about Alexandria, it's great library and librarians, Egypt, Syene, Greeks of the time, influential Indian and Muslim scientists who followed in Eratosthenes' footsteps, and a slew of other topics. Just good stuff.

[Mike · Rating 3 out of 5]

Nothing new in this and a few minor flaws from an author who would seem to pride himself on his historical accuracy. Nevertheless, it's a more rewarding read than his fiction. There is not a great amount of material for the non-academic regarding Eratosthenes so Nicastro's book is a welcome addition despite it's shortcomings.

[Ian · Rating 4 out of 5]

My review on LibraryThing.

[Larry · Rating 3 out of 5]

about Eratosthenes, Greek head of Library of Alexandria. Figured out earth's circumference. A bit of heavy lifting later in book.