April 8, 240 b.c.e.
Eratosthenes of Cyrene
Chief Librarian
Great Library of Alexandria
Alexandria, Egypt
Dear Eratosthenes,
Greetings my dear friend. I congratulate you on your recent measurements of the globe, though I suspect your eyes will suffer from so much gazing at the sun to achieve it. If you are hungry for it I require your assistance in the computation of the number of Helios’ cattle. They are horned, though that may make little difference as all are worth the same money horns or no horns. They live in four herds of different colors, white, black, yellow, and dappled. Each herd has bulls in these proportions: the white bulls are equal to a half and a third of the black together with all of the yellow. The black are equal to the fourth part of the dappled, and a fifth, together with again, all of the yellow. The remaining bulls, the dappled ones, … More
