From Mike Jewess
Michael Goldfarb of Vanderbilt University has established that steam power is the most efficient way to power humanoid robots, with the steam being generated by the palladium-catalysed decomposition of hydrogen peroxide (27 April, p 19). This avoids heavy batteries or the complexities of an internal combustion engine. The only noise comes from the occasional hiss as spent steam is expelled.
So now we know why Marvin, the paranoid android in the The Hitchhiker’s Guide to the Galaxy, although endowed with “a brain the size of a planet”, produced a hissing sound with every step he took.
Harwell, Oxfordshire
