Al-Biruni
A polymath measures the Earth from a mountain and writes an honest book about India.
- When
- —
- Duration
- 31 years
- Known to
- ± 10 years
- Era
- Post-Classical, Holocene
Al-Biruni computes the Earth's radius from the angle of the horizon seen from a hilltop, getting within about one per cent, determines specific gravities of eighteen substances to remarkable precision, and — having travelled with Mahmud of Ghazni's campaigns — writes a study of Indian religion, science and custom that makes a deliberate effort to describe beliefs as their holders understood them rather than as errors.