The first vending machine is 2,000 years old

Hero of Alexandria, a Greek engineer of the first century, described in his treatise 'Pneumatica' a strikingly familiar machine: you dropped a coin through a slot and the device dispensed a dose of water.

The mechanism was pure elegance: the coin fell onto a small tray attached to a lever; its weight tipped the lever and opened a valve; water flowed while the coin slid along the tray, and when it dropped into the bottom of the box, the valve closed by itself. An exact dose, no attendant required.

The problem it solved sounds modern too: in the temples of Egypt, worshippers were taking more lustral water than they paid for. Hero's machine charged them without arguing.

Then the idea went to sleep. Nearly eighteen hundred years later, in the London of the 1880s, coin-operated machines selling postcards and chewing gum reappeared — and that's where we come from: every time a machine swallows your coin and gives you nothing back, you are taking part in a tradition twenty centuries old.