21. Eratosthenes eratosthenes of cyrene”. http//www.share2.esd105.wednet.edu/jmcald/Aristarchus/eratosthenes.html.“Eratosthenes Who Was eratosthenes of cyrene”. http://www.3villagecsd.k12.ny.us/wmhs/Departments/Math/OBrien/eros.html

Eratosthenes Eratosthenes was an important mathematical figure of ancient Greece. Among his accomplishments was the accurate measurement of the earth's circumference. He also wrote works on mathematics, geography, philosophy, and astronomy. Although many of his works have been lost, historians have uncovered a substantial amount of information about important events in his life and his accomplishments. Q: Where were you born and where did you grow up? A: I was born in Cyrene, Greece (which is present-day Libya, in South Africa), in 276 B.C. Both of my parents were Greek and there, on the coast of Africa, I grew up. Q: Did you have any nicknames growing up? A: I did have one; my friends called me Beta, which is the second letter of the Greek alphabet. They teased with me, saying I fell just short of first place (which was occupied by Archimedes). Later on in my life, I received the nickname Pentathlos. It's funny, because literally this word refers to an athlete that participated in 5 sporting events, but eventually was used to describe someone who was well-rounded, or good at several different things. Q: What was your childhood like?

22. Erastosthenes 2. eratosthenes of cyrene. http//www.eranet.gr/eratosthenes/html/eoc.htmlA professional site unlike the one above. A bit oversimplified http://www.3villagecsd.k12.ny.us/wmhs/Departments/Math/OBrien/eros2.html

Erastosthenes Cyrene 215 B.C. Q (me, the interviewer): Greetings WM Times readers! We are pleased to present to you an exclusive interview with the now-legendary mathematician, Eratosthenes, who has developed a method for measuring the earths' circumference through math, without traveling around the world in order to do so. In fact, only a fraction of travel was required. It's great to have this exclusive interview, Eratosthenes! A (Eratosthenes): I am glad to be here. I believe this to be a great discovery and am anxious to share it with the scientific community, as well as the world! Q: Nice to hear that. First, let us start off with a little background information. Where were you born, Eratosthenes? A: I was born in Cyrene, which is also where this interview is taking place. Q: How did you get into mathematics? A: I became very interested in mathematics growing up, and met a friend that soon became my mentor, Archimedes. Challenging my intelligence, he would send me math problems on a regular basis for me to solve. He would later send the solution so I could compare with my own. My intellectual strength grew quickly. Q: Amazing! Any early accomplishments?

23. Eratosthenes eratosthenes of cyrene. Born 276 BC in Cyrene (now Shahhat, Libya) Died 197 BCin Alexandria, Egypt. Eratosthenes was born in Cyrene which is now in Libya. http://monet.unibas.ch/~guggisbe/kurs/lek1/Eratosthenes.html

Eratosthenes of Cyrene Born: 276 BC in Cyrene (now Shahhat, Libya) Died: 197 BC in Alexandria, Egypt Eratosthenes was born in Cyrene which is now in Libya. After studying in Alexandria and Athens he became the director of the Library in Alexandria. He worked on geometry and prime numbers. He is best remembered for his prime number sieve which, in modified form, is still an important tool in number theory research. Eratosthenes also made a surprisingly accurate measurement of the circumference of the Earth. He compared the noon shadow in midsummer between Syene (now Aswan) and Alexandria. He gave the circumference of the Earth as 250000 stadia, the distance to the sun as 804000000 stadia and the distance to the Moon as 780000 stadia. He measured the tilt of the Earth's axis with great accuracy obtaining the value of 23 51' 15". He compiled a star catalogue containing 675 stars. Eratosthenes became blind in his old age and is said to have committed suicide by starvation. JOC/EFR December 1996 The URL of this page is: http://www-history.mcs.st-andrews.ac.uk/history/Mathematicians/Eratosthenes.html

24. PowerBasic Crypto Archives News eratosthenes of cyrene Links http//wwwgap.dcs.st-and.ac.uk/~history/Mathematicians/Eratosthenes.htmlBack to The Archives. http://www.pbcrypto.com/greatminds/eratosthenes.php

Eratosthenes of Cyrene Links: http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Eratosthenes.html Back to The Archives

25. PowerBasic Crypto Archives - The Sieve Of Eratosthenes NAME The Sieve of Eratosthenes CREATOR eratosthenes of cyrene 276 196 BC PBAUTHOR Eric Pearson DESCRIPTION Search for prime numbers using the Sieve of http://www.pbcrypto.com/view.php?algorithm=eratosthenes

26. Eratosthenes Of Cyrene Example Essays.com - Over 101,000 Essays, Term Papers And eratosthenes of cyrene Britannica Concise Encyclopedia Online Britannica Concise Encyclopedia, eratosthenes of cyrene Britannica Concise. MLAstyle eratosthenes of cyrene. Britannica Concise Encyclopedia. 2004. http://www.exampleessays.com/viewpaper.php?request=2231

27. Consal ; Consal Communities - SPECIAL COLUMN Title. References on eratosthenes of cyrene. Message. The referencesare provided by Dr. John J O Connor and Prof. Edmund F Robertson. http://www.consal.org.sg/forums/forum.asp?F=111&M=1548

28. Eratosthenes eratosthenes of cyrene (bc 276 BC, Cyrene, Libyadc 194, Alexandria, Egypt),Greek scientific writer, astronomer, and poet, the first man known to have http://zebu.uoregon.edu/~js/glossary/eratosthenes.html

Eratosthenes After study in Alexandria and Athens, Eratosthenes settled in Alexandria about 255 BC and became director of the great library there. He worked out a calendar that included leap years, and he tried to fix the dates of literary and political events since the siege of Troy. His writings include a poem inspired by astronomy, as well as works on the theatre and on ethics. Eratosthenes was afflicted by blindness in his old age, and he is said to have committed suicide by voluntary starvation.

29. Eratosthenes eratosthenes of cyrene (c. 276 BC – c. 197 BC) lived in Alexandria. He was bornin Cyrene which is now in Libya. He worked on geometry and prime numbers. http://www.mlahanas.de/Greeks/Eratosthenes.htm

Eratosthenes Eratosthenes provided an estimate of the Earth diameter. Eratosthenes knew that the Earth is spherical and he wanted to measure its diameter. Democrit . Eratosthenes came to Alexandria from Athens to be the chief librarian of Ptolemy Euergetes. He was not merely an astronomer and a geographer, but a poet and grammarian as well. His contemporaries jestingly called him Beta the Second , because he was said through the universality of his attainments to be "a second Plato" in philosophy, "a second Thales" in astronomy, and so on throughout the list. For the same reason he was called a Pentathlos which means and athlete in five disciplines. We know indirect what he did by Strabo and Cleomedes who wrote 150-200 years later about Eratosthenes. BOOKS Geographica with maps and information of distance measurements. The map by Eratosthenes includes India, Sri-Lanka (Ceylon) and UK up to Thule in the North visited by Pytheas. Stories and Poems such as Hermes and Epigone Thales made measurements with the aid of shadows using the gnomon , which is the most primitive, but which long remained the most important, of astronomical instruments. It is believed that Eratosthenes invented an important modification of the gnomon which was elaborated afterwards by Hipparchus and called an

30. LookSmart - Directory - Eratosthenes eratosthenes of cyrene Biography of Eratosthenes, who very accuratelymeasured the circumference of the Earth more than 2000 years ago. http://search.looksmart.com/p/browse/us1/us317914/us328800/us518756/us572631/

@import url(/css/us/style.css); @import url(/css/us/searchResult1.css); Home IN the directory this category YOU ARE HERE Home Sciences Mathematics Mathematicians Eratosthenes - Learn about one of the foremost geometers of the ancient world, Eratosthenes. Directory Listings About Encyclopedia.com - Eratosthenes Briefly profiles the accomplishments of the ancient Greek scholar, author, astronomer, and mathematician of Alexandria, Egypt. Eratosthenes - Ancient Geometry Studies the works of the revered geometer and mathematician of ancient Alexandria. Eratosthenes - Geographer Quick profile of the famed geographer who took over directorship of the library of Alexandria after the resignation of Apollonius of Rhodes. Eratosthenes - Univ. of Utah Read about the first scholar to accurately estimate the diameter of the earth. Includes information on ancient geography. Eratosthenes of Cyrene Biography of Eratosthenes, who very accurately measured the circumference of the Earth more than 2000 years ago. Wolfram Research - Eratosthenes of Cyrene (ca. 284-196 BC) Short biography of the mathematician covers his research into astronomy and prime numbers. We're always looking for ways to improve your search experience.

31. PSIgate - Physical Sciences Information Gateway - Web Catalogue Eratosthenes eratosthenes of cyrene Born 276 BC in Cyrene, North Africa (now Shahhat,Libya) Died 194 BC in Alexandria, Egypt Click the picture above to see http://www.psigate.ac.uk/roads/cgi-bin/search_webcatalogue.pl?term1=Eratosthenes

32. Ancient Map Web List 112, Reconstruction of the World map, (eratosthenes of cyrene), moderrn (194 BC).112A, Reconstruction of the World map, (eratosthenes of cyrene), moderrn (194 BC). http://www.henry-davis.com/MAPS/Ancient Web Pages/AncientL.html

Index of Cartographic Images illustrating maps from the Ancient Period: 6,200 B.C. to 400 A.D. Below are listed the cartographic images in my collection. Each of these items currently have links to the associated image and/or monograph web pages. If you see a map that you would like to view, simply click on that underlined number. If there are maps that you would like to see but do not currently have links to them, simply e-mail your request to jsiebold@cfl.rr.com and I will e-mail the page(s) directly to you ASAP. Time Chart of Ancient Cartography Slide # Title: Cartographer: Date: (redrawing) James Mellaart Modern (6200 B.C.) unknown 6200 B.C. unknown 6200 B.C. unknown 6200 B.C. Clay tablet from Ga-Sur unknown 2300 B.C. Clay tablet from Ga-Sur unknown 2,500 B.C. Clay tablet from Ga-Sur unknown (2,500 B.C.) Clay tablet from Ga-Sur unknown (2,500 B.C.) Mesopotamian City Plan, Nippur unknown 1500 BC Turin Papyrus unknown 1300 B.C. Turin Papyrus (interpretive drawing) unknown modern (1300 B.C.) Babylonian clay tablet, 600 B.C unknown 600 B.C.

33. Slide #112 Monograph TITLE World according to Eratosthenes DATE 194 BC AUTHOR eratosthenes of cyreneDESCRIPTION This slide shows a 19th century reconstruction of the world http://www.henry-davis.com/MAPS/Ancient Web Pages/112mono.html

Slide #112 TITLE: World according to Eratosthenes DATE: 194 B.C. AUTHOR: Eratosthenes of Cyrene DESCRIPTION: Slide #111 ). Geographic information that was gathered by Alexander the Great and his successors was the primary source used by Eratosthenes, a scholar with vision large enough to put this information into a logical framework. There can be no doubt that before the time of Eratosthenes the ideas of the learned world on the subject of geography had assumed a more regular and systematic form. And it is certain also that these had been embodied in the form of maps, which, however imperfect, were unquestionably very superior to anything that had preceded them. The first use of world maps by the Greeks had been introduced at a very early period by Anaximander (ca. 610-546 B.C. Slide #107 ), and maps of the world were not uncommon in the time of Herodotus (ca. 489-425 B.C. Slide #109 Slide #109 and Slide #108 Eratosthenes, head of the Library at Alexandria from 240 B.C. until his death, was known as beta to his contemporaries because they considered him second in all his varied academic pursuits. More critical of these accomplishments was Strabo (63 B.C.?- A.D.24, Slide #115 ) to whom we are indebted for much of our knowledge of geography in antiquity, including the work of Eratosthenes whose relevant works, neither of which survived, were

34. Sieve Of Eratosthenes Repeatedly take the next unmarked integer as the next prime and mark every multipleof the prime. Note Invented by eratosthenes of cyrene (276 BC 194 BC). http://www.nist.gov/dads/HTML/sieve.html

sieve of Eratosthenes (algorithm) Definition: An algorithm to find all prime numbers up to a certain N. Begin with an (unmarked) array of integers from 2 to N. The first unmarked integer, 2, is the first prime. Mark every multiple of this prime. Repeatedly take the next unmarked integer as the next prime and mark every multiple of the prime. Note: Invented by Eratosthenes of Cyrene (276 BC - 194 BC). For example, here's a beginning array. Since 2 is unmarked, it is our first prime. We mark every second integer, that is, 4, 6, 8, 10, 12, etc. The next unmarked integer is 3, so it is prime, and we mark every third integer, i.e., 6, 9, 12, etc. Note that we mark 6, 12, 18, etc. again. Now 5 is the next prime, and we mark every fifth integer. The only new integer marked in range is 25. From here we find the primes 7, 11, 13, 17, etc. To optimize, when we find the prime n, we can begin marking at n , since any composite less than that is a multiple of a lesser prime, and so will have been marked earlier. As a corollary, we can stop marking when n is greater than our range. That is, any unmarked numbers greater than the square root of the range are primes.

35. Lecture 4: Measuring The Earth Circumference eratosthenes of cyrene; Claudius Ptolemy. The Four Cornersof the Earth. Answer Use Geometry. eratosthenes of cyrene. Born http://www-astronomy.mps.ohio-state.edu/~pogge/Ast161/Unit2/measearth.html

Astronomy 161: An Introduction to Solar System Astronomy Prof. Richard Pogge, MTWThF 9:30 Lecture 4: Measuring the Earth Key Ideas: Ancient ideas about the Earth. Flat Earth, World Tree or World Mountain The Spherical Earth Appeal to perfect symmetry Demonstration by Aristotle Measuring the Earth's Circumference: Eratosthenes of Cyrene Claudius Ptolemy The Four Corners of the Earth The most common ancient theme is that of a Flat Earth. Homeric: A flat disk surrounded by a world ocean. Inca: Called their land Tehuantinsuyu: "The Four Corners of the Earth" Ancient Egyptian: The sky was a tent canopy stretched between mountains at the four corners of the Earth. World Trees and Mountains also figure in early mythology: Hindu Vedas: Tree of Knowledge holding up the Universe. Norse Eddas: Yggdrasil, the World Ash Tree Brahmin World Mountain, resting on the back of elephants, themselves on the back of a giant turtle swimming in an infinite sea. These fanciful views are Representations rather than Portrayals of reality.

36. MSN Encarta - Eratosthenes , Earth measurements. 5 items. Selected Web Links. , eratosthenes of cyrene MacTutor.1 item. Want more Encarta? Become a subscriber today and gain access to http://encarta.msn.com/encyclopedia_761557529/Eratosthenes.html

MSN Home My MSN Hotmail Shopping ... Money Web Search: logoImg('http://sc.msn.com'); Encarta Subscriber Sign In Help Home ... Upgrade to Encarta Premium Search Encarta Subscription Article MSN Encarta Premium: Get this article, plus 60,000 other articles, an interactive atlas, dictionaries, thesaurus, articles from 100 leading magazines, homework tools, daily math help and more for $4.95/month or $29.95/year (plus applicable taxes.) Learn more. This article is exclusively available for MSN Encarta Premium Subscribers. Already a subscriber? Sign in above. Eratosthenes Eratosthenes bc ), Greek mathematician, astronomer, geographer, and poet, who measured the circumference of the earth with extraordinary... Related Items adoption of word “geography”  Earth measurements 5 items Selected Web Links Eratosthenes of Cyrene [MacTutor] 1 item Want more Encarta? Become a subscriber today and gain access to: Daily Math Help Literature Guides Researcher Tools Paper-Writing Guides 60,000 + articles Interactive Atlas Magazine Center Find more about Eratosthenes from Related Items Other Features from Encarta Geography Science Map Physics ... Try MSN Internet Software for FREE!

37. Eratosthenes Eratosthenes was born in Cyrene, Greece, which is now known as Libya, in SouthAfrica, in 276 BCE. AddisonWesley. New York; 1996. eratosthenes of cyrene. http://www.math.wichita.edu/history/men/eratosthenes.html

Eratosthenes 276-195 B.C.E. It can be said that Eratosthenes is most widely known as a famous Greek mathematician. What most people probably do not know is that Eratosthenes is not only a famous mathematician but also a well known geographer, astronomer and historian. Before I get into a few of his accomplishments, let me tell you a little about his personal history. Eratosthenes was born in Cyrene, Greece, which is now known as Libya, in South Africa, in 276 B.C.E.. It is believed that he starved himself to death in 195 B.C.E. due to the fact that he became blind and could no longer work. As a young man, Eratosthenes studied in Athens. Eventually, he made such a name for himself in his many fields that he caught the attention of the ruler of Egypt, Ptolemy III. Ptolemy III invited Eratosthenes to Alexandria, Egypt for two reasons; to tutor his son and to be the librarian for the great Alexandrian University. Eratosthenes jumped at the chance. At the University, he was able to at most interested him and associate with other scholars. Now on to his accomplishments. . . One of his major accomplishments in mathematics is his creation of a sieve that determines prime numbers up to any given limit. This sieve, which is called, the Sieve of Eratosthenes, is still important today in number research theory. Prime numbers are natural numbers greater than 1 that can be divided without remainder only by itself and by 1. Eratosthenes figured out that if you were to write down all the natural numbers from 2 to infinity and "sieve out" every second number after two (or multiples of two), then move to the next available number (3) and continue to "sieve out" every multiple of 3 and so on, one would end up with a list of prime numbers.

38. Eratosthenes eratosthenes of cyrene. Born 276 BC in Cyrene (now Shahhat, Libya) Died 197 BCin Alexandria, Egypt. Eratosthenes was born in Cyrene which is now in Libya. http://intranet.woodvillehs.sa.edu.au/pages/resources/maths/History/rtsthns.htm

Eratosthenes of Cyrene Born: 276 BC in Cyrene (now Shahhat, Libya) Died: 197 BC in Alexandria, Egypt Previous (Chronologically) Next Biographies Index Previous (Alphabetically) Next Welcome page Eratosthenes was born in Cyrene which is now in Libya. After studying in Alexandria and Athens he became the director of the Library in Alexandria. He worked on geometry and prime numbers. He is best remembered for his prime number sieve which, in modified form, is still an important tool in number theory research. Eratosthenes also made a surprisingly accurate measurement of the circumference of the Earth. He compared the noon shadow in midsummer between Syene (now Aswan) and Alexandria. He gave the circumference of the Earth as 250000 stadia, the distance to the sun as 804000000 stadia and the distance to the Moon as 780000 stadia. He measured the tilt of the Earth's axis with great accuracy obtaining the value of 23 51' 15". He compiled a star catalogue containing 675 stars. Eratosthenes became blind in his old age and is said to have committed suicide by starvation. References (15 books/articles) References elsewhere in this archive: Tell me about the sieve of Eratosthenes Tell me about Eratosthenes' part in the longitude problem There is a Crater Eratosthenes on the moon. You can see a

39. Math History - Pre-historic And Ancient Times About 235BC, eratosthenes of cyrene estimates the Earth s circumferencewith remarkable accuracy finding a value which is about 15% too big. http://lahabra.seniorhigh.net/pages/teachers/pages/math/timeline/MpreAndAncient.

40. Eratosthenes Eratosthenes Lost literature Greece Elegiac poetry, Greek . Eratosthenesof Cyrene. eratosthenes of cyrene PM Fraser Eratosthenes . http://topics.practical.org/browse/Eratosthenes

topics.practical.org Eratosthenes The Librarian Who Measured the Earth Kevin Hawkes Kathryn Lasky Eratosthenes ... Eratosthenes

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