Energy
A book on architecture and engineering by Roman architect Vitruvius (Marcus Vitruvius Pollio) [b. c. 90 bce, d. c. 20 bce] also discusses astronomy, acoustics, sundials, and water wheels. His De architectura libri decem ("ten books on architecture") will remain the main source of knowledge about Roman construction until the Renaissance. The "Vitruvian" water wheel is the first known instance of a vertical, undershot water wheel (the water runs beneath the wheel). Gearing is used to make the speed of the millstone one-fifth the speed of the wheel, a great improvement for grinding of grain. This type of wheel probably developed from the kinds of water wheels used for centuries for raising water for irrigation.
MaterialsVitruvius describes gold amalgam, that is, gold dissolved in mercury. See also 100 bce Chemistry.
