Eratosthenes Measures the Earth

287 BC to 212 BC in Syracuse, Sicily Greece


Biographical Info on MacTutor

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 . . . Thus may it be, and let any one who sees this offering say
"This is the gift of Eratosthenes of Cyrene".       

Eratosthenes epigram on a column in Alexandria

Measuring the Circumference of the Earth:

Eratosthenes' Method
Measure the Earth Sci Project
Eratosthenes & the Earth's Diameter
Math Forum Explains EM

Prime Number Sites:

Prime Number Quiz
Prime Number Machine
Eratosthenes Sieve (Javascript demo)
Eratosthenes Sieve - another demo
Murderous Maths Prime Game
The Prime Pages
Largest Known Primes
Patterns in Prime Numbers
Prime Number Cascade

Prime numbers, trigonometry, math and geography,large numbers, proportion and ratio.