An ancient Alexandrian built a coin-operated vending machine for holy water
Drop a coin into Hero's machine and it landed on a small pan, tipping a lever that opened a valve and let out a measured dose of water for ritual washing. When the coin slid off, a counterweight shut the flow. Hero of Alexandria also described a steam-driven spinning device and a wind-powered organ.
Hero, or Heron, was a Greek mathematician and engineer working in Roman-era Alexandria, probably in the 1st or 2nd century AD, though estimates range from 150 BC to 250 AD. Almost nothing is known of his life. Otto Neugebauer matched an eclipse used as an example in Hero's Dioptra to one in 62 AD, but the reference is vague. Some of his writings read like lecture notes, suggesting he taught at the Mouseion, the institution that housed the Library of Alexandria. He has been called the greatest experimenter of antiquity and borrowed some ideas from Ctesibius.
His inventions are a catalogue of ingenuity. The aeolipile, or Hero's engine, was a reaction device spun by steam, the first recorded steam engine, although Vitruvius mentioned an aeolipile earlier. A separate device used air heated by an altar fire to push water into a vessel whose weight pulled open temple doors; historians have sometimes merged the two to claim the aeolipile did useful work. He also described a wind wheel driving an organ, the first documented wind-powered machine, a force pump used in Roman fire engines, a self-contained fountain now named after him and a cart propelled by a falling weight.
For the theatre he designed an entirely mechanical play nearly ten minutes long, run by ropes, knots and a rotating cylinder, with metal balls dropped onto a hidden drum for thunder. He also knew that air expands and contracts with heat and demonstrated it with a tube dipping into water, an ancestor of the thermometer.
In mathematics he is remembered for Heron's formula, giving a triangle's area from its three sides, and an iterative method for square roots. Studying the shortest route between two points via a line, he stated that light travelling within one medium takes the shortest path, an idea Ibn al-Haytham extended and Pierre de Fermat restated in 1662. Many writings are lost, surviving mostly in Byzantine copies; a five-volume edition appeared in Leipzig in 1903.
Source: Hero of Alexandria
