The Greek mathematician and astronomer Eratosthenes (275-195 B.C.) utilised a comparison among shadows to evaluate the Earth's circumference. Eratosthenes knows that to the working day in the sum mer solstice at midday the sun will be mirrored at the bottom of a particular properly in Siene (present day Assuan in https://www.scientology.de/daily-connect/scientologists-at-home/cooking-up-some-awesome-with-diana-home-958db3f0