Had always assumed there must be some method behind the madness of standard resistor sizes (why the obsession with 4.7?) but never knew exactly what it was - and the explanation here is excellent. The fact they fall along a twelfth-root scale is an intriguingly direct mapping to musical semitones; I wonder if that was ever significant in enabling the creation of early electronic instruments?

edit - on second thoughts, twelfth root of ten isn't particularly helpful for musical notes, where the factor between semitones is the twelfth root of two. So... carry on.