My vanished question is:"'How does a slide rule work?"' Slide rules were once ubiquitous in labs, classrooms, and the pockets of engineers. They are now as common as dinosaurs; totally replaced by electronic calulators and computers. The interesting question to ponder is: what is it that in the future will do to computers what computers did to slide rules?
JOHN BARROW is a physicist at Cambridge University.. He is the author of The World Within the World, Pi in the Sky, Theories of Everything, The Origins of the Universe (Science Masters Series),The Left Hand of Creation, The Artful Universe, and Impossibility: The Limits of Science and the Science of Limits.