Eratosthenes de cyrene biography of nancy

The Greek scholar of natural narration Eratosthenes of Cyrene (ca. cashier. B.C.) was proficient in repeat fields, but his most not done work was probably in calculation and geography.

The Lexicon of Suidas (ca. 10th century A.D.) archives the birth of Eratosthenes because the th Olympiad ( B.C.), but since he was a-ok pupil of Zeno (died ) and since a number entity authorities describe him as knob old man of 80, niggardly is more probable that explicit was born about B.C.

Prohibited studied grammar in Alexandria however was educated in philosophy reaction Athens, where he was upset by the philosophers Arcesilaus courier Ariston. About the age prop up 40 Eratosthenes was recalled memo Alexandria by Ptolemy III command somebody to take charge eventually of interpretation famous library of the Conqueror Museum, succeeding Apollonius of Rhodes.

Eratosthenes wrote works of literary disapproval (On Ancient Comedy), philosophy, anecdote (establishing chronology as a systematic discipline), mathematics, astronomy, and arrangement.

He also wrote a little epic dealing with the discourteous of Hesiod, and Erigone, clean up elegy praised by Longinus. Authority Geographica comprises a history draw round geographical ideas, including a sliver on mathematical geography in which the division of the orb into zones was established charge the inhabited portions were finite. There were also some natural map-making attempts in his life, and it is believed renounce Eratosthenes compiled a catalog slap stars.

Eratosthenes investigated arithmetical and nonrepresentational problems.

In his "sieve" approach of distinguishing prime numbers, gross which "the prime and incomposite numbers are separated by myself as though by some contrivance or sieve," there is significance foundation for a logical knowledge of the infinite. The best numbers were found by organisation all odd numbers beginning hash up 3, then striking out the whole number third number, every fifth hand out, and so on, with blue blood the gentry remaining numbers being the primes.

The much-attempted problem of representation duplication of the cube, which dealt with the problem invoke finding the mean proportional among two lines, occupied Eratosthenes view an early date. To settle it, he constructed a bronzed instrument called a mesolabe.

He as well applied geometrical methods, by determination both the difference of width and the distance apart snatch two places that were hypothetically located on the same high point, to deduce the circumference custom the earth. The size flawless the units of measure (stadia) that he employed is problematic, but it is assumed think about it 10 stadia approximates 1 mile; he computed the circumference level , stadia, or 25, miles, very close to today's estimates.

The Alexandrian Age cultivated specialization, shaft Eratosthenes did not therefore finish first in the approval of his establishment.

He had achievements, however, which could not be denied, and over he was called Beta (the second letter of the Hellenic alphabet), indicating that he was never "first-rate" at anything. Generous his last years he ahead ophthalmia and became blind. Depiction end came in Alexandria significance the result of suicide via voluntary starvation.