Leonardo Torres Quevedo

Torres Quevedo (1852–1936) was a civil engineer who built most things. Cable cars: his aerocar over the whirlpool below Niagara Falls opened in 1916 and still runs. Semi-rigid airships, flown by the French and British navies in the First World War. And the Telekino, a radio control system that in 1906 steered a boat around Bilbao harbour with eight people aboard — among the first remote-control devices anywhere.

What should have made his name is Ensayos sobre Automática (1914). In it he sketches an analytical engine in Babbage's spirit but electromechanical rather than mechanical, with conditional branching, a read-only store made of fixed wiring, and what is generally reckoned the first description of floating-point arithmetic: a number held as mantissa and exponent, so the scale need not be chosen in advance. In 1920 he demonstrated in Paris an arithmometer wired to a typewriter — you typed the problem, and the machine typed back the answer.

None of it was built on. He published in Spanish and French, died in December 1936 with the civil war outside his window, and when the next generation rediscovered floating point they did so without knowing that someone had already written it down.