It's clear that we would divide the art of measurement, cutting it in two in just the way we said, positing as one part of it all those sorts of expertise that measure the number, lengths, depths, breadths and speeds of things in relation to what is opposed to them, and as the other, all those that measure in relation to what is in due measure, what is fitting, the right moment, what is as it ought to be everything that removes itself from the extremes to the middle.