Engineering · a Light

Three brothers designed machines that regulated themselves

Muhammad, Ahmad and al-Hasan, the sons of Musa ibn Shakir, were astronomers and patrons in ninth century Baghdad who paid translators out of their own pockets. Around 850 they produced the Book of Ingenious Devices, about a hundred machines. Most are vessels and fountains that do something unexpected, which makes them look like toys, and the surprise is nearly always a hidden control: a float that rises with the liquid and closes a valve, a siphon that empties a chamber at a set level, a lamp that trims its own wick and draws up its own oil. That is feedback, a machine holding a condition steady with no hand on it. They also describe a grab for lifting objects off a riverbed. Donald Hill translated the book into English in 1979.

Banu Musa · Baghdad, c. 850 CE