Eratosthenes, the Most Knowledgeable Man in the World
Eratosthenes was born in 276 B.C. in Cyrene, Libya. He has been known by many names including Philologos (the friend of learning), Pentathos by his friends because of his varied accomplishments and Beta because he was the second most knowledgeable in all branches of learning but never the first ("NNDB tracking the entire world"). From his earliest childhood, he was a great thinker. He loved school and he loved learning. He was a student who could not get enough information. He was always asking questions in an attempt to quench his thirst for knowledge. Instead of becoming satiated with what he learned in the gymnasium, which is what school was called, the knowledge that he derived just drove him further into his studies. His parents and instructors realized that they had a unique individual who was capable of doing great things.
When Eratosthenes was young, he was called to attend school away from his home. He had instruction from brilliant men like Callimachus of Alexandria, the Stoic Ariston, and the Academic Arcesilaus of Athens. Eratosthenes tried the patience of these men dearly. They wanted him to learn specific lessons but Erasthones’ mind was always running from one point to another. He would have the answer and then ask even more questions. Soon he had learned all that he could from his teachers (Lasky, and Hawkes 15).
In today’s classrooms, many students like this would be treated as having ADD or ADHD instead of being looked at as highly intelligent. The world is lucky that Eratosthenes’ teachers saw the potential that was within him and worked with him. When Eratosthenes learned all that he could he said good-bye to all that he knew and moved to the Greek capital so that he had a chance to learn even more. This is where he was able to learn more about his favorite subjects, geography and math.
The world at that time was greatly centered on the Greek leaders. They were being lead by Ptolemy III Euergetes and he found interest in Eratosthenes. He summoned Eratosthenes back to Alexandria and appointed him chief librarian in place of his old teacher, Callimachus ("NNDB tracking the entire world"). Eratosthenes was one of the first to try to categorize and compile information that was alike in one area or in one book. To do this, he had to read many pappus and transcribe them onto other scrolls (Lasky, and Hawkes 24). This made him even more educated in even more subjects.
While Eratosthenes was transcribing this information, he learned much more than anyone could have believed possible. He was able to retain this information and connect one piece of information in one subject, like astronomy, to another subject, like math or science, and make sense of it. Being able to do this did not settle his unending questions or his want for knowledge. Instead, it drove him to ask more ‘what if’ questions. Luckily, for the world, Eratosthenes wrote down his ‘what if’ questions, the answers, and the processes by which he found his answers. He was one of the first hypothesizers of the world.
One book that Eratosthenes wrote was On Means. This book has been lost but we know that it was written because it has been referenced by other scholars like Eutocius. Eratosthenes also derived a ‘program’ for discovering prime numbers. This is what is referred to as the “Sieve of Eratosthenes.” What he discovered is that this sieve can identify all prime numbers up to a given number n. The sieve works in the following manner: 1. Include all numbers {1, 2, 3, …, n}. Composites will be eliminated but are left unmarked at the beginning. 2. The number 1 is marked as a special number as it is neither a composite or a prime number. 3. K is set to equal 1. Until k equals or exceeds the square root of n, the following must be done: a. Find the first numbers on the list that are greater than k that have not yet been identified as composite numbers. These can be identified as m. These m numbers are to be marked. b. 2m, 3m, 4m, … So far all even numbers greater than two have been marked. The next run would mark all multiples of three that are greater than three. c. m is a prime number and now goes on the list. d. k is not set to m and the process is repeated. 4. The numbers that remain unmarked in the sequence are what have made it through the sieve and are the prime numbers (Alfeld).
Another important work of Eratosthenes was Platonicus. This writing was used be Theon of Smyrna in Expositio rerum mathematicarum and gives definitions that are used in arithmetic, geometry and also in music. There are other writings that are also attributed to Eratosthenes that include a way to find line segments x and y so that for given segments a and b, a: x = x: y = y: b (O'Connor, and Robertson). Through his pursuit in finding solutions to mathematical questions, Eratosthenes became upset with the Greeks. To this he erected a column in Alexandria which he inscribed, “If, good friend, thou mindest to obtain from any small cube a cube the double of it, and duly to change any solid figure into another, this is in thy power; thou canst find the measure of a fold, a pit, or the broad basin of a hollow well, by this method, that is, if thou thus catch between two rulers two means with their extreme ends converging. Do not thou seek to do the difficult business of Archytas's cylinders, or to cut the cone in the triads of Menaechmus, or to compass such a curved form of lines as is described by the god-fearing Eudoxus. Nay thou couldst, on these tablets, easily find a myriad of means, beginning from a small base. Happy art thou, Ptolemy, in that, as a father the equal of his son in youthful vigour, thou hast thyself given him all that is dear to muses and Kings, and may be in the future, O Zeus, god of heaven, also receive the sceptre at thy hands. Thus may it be, and let anyone who sees this offering say "This is the gift of Eratosthenes of Cyrene (O'Connor, and Robertson)”.
After erecting this column, Eratosthenes saw that the sun was casting shadows at the same time in the same places each day. This made him begin to question some more. He began to wonder if this happened all over the world. That also made him question about the size of the Earth. Eratosthenes used a grapefruit as a comparison to the world. Eratosthenes was the first to figure the circumference of the world and he was only 200 miles different from modern-day calculations. (Lasky, and Hawkes 30-41).

("Famous People")
Eratosthenes’ life came to an end around 194 B.C. through self-imposed starvation. This was done because of his oncoming blindness (Encyclopædia Britannica). Before this happened, Eratosthenes became, in my opinion, the most educated man in the world even though he was never the most educated in one subject. He was highly admired by his peers, his government and by those who were lucky enough to study from him and he is highly admired by those who are able to study his works now.

Works Cited Page

Alfeld, Peter. "The Sieve of Eratosthenes." Mathematics. The University of Utah, 02-Jun-1998. Web. 17 Sep 2011. http://www.math.utah.edu/~pa/Eratosthenes.html.
Lasky, Kathryn, and Kevin Hawkes. The Librarian Who Measured The Earth. 1st ed. New York: Little, Brown Books for Young Readers, 1994. 15-41. Print. http://books.google.com/books/feeds/volumes?q=0-316-51526-4.
"Eratosthenes." NNDB tracking the entire world. Soylent Communications , 2011. Web. 15 Sep 2011. http://www.nndb.com/people/712/000095427/.
"Eratosthenes (276 - 195 B.C.)." Famous People. Cornell University, n.d. Web. 17 Sep 2011. http://www.astro.cornell.edu/academics/courses/astro201/eratosthenes.htm.
"Eratosthenes of Cyrene." Encyclopædia Britannica. Encyclopædia Britannica Online Academic Edition. Encyclopædia Britannica, 2011. Web. 25 Aug. 2011. <http://www.britannica.com/EBchecked/topic/191064/Eratosthenes-of-Cyrene>.
O'Connor, J J , and E F Robertson. "Eratosthenes of Cyrene." MacTutor History of Mathematics. School of Mathematics and Statistics University of St Andrews, Scotland, 01/1999. Web. 17 Sep 2011. http://www-history.mcs.st-andrews.ac.uk/Biographies/Eratosthenes.html.