“Eureka!” You know who said that? Archimedes did. You know why? Because he figured out how to measure the density of gold, while slipping into a bath—so goes the legend—after which he immediately spoke the famous word, and went padding off down the street, leaving wet footprints, presumably on the way to some off-camera laboratory. (Apparently visionary Sicilian technologists were so well esteemed, in the highly civilized Hellenistic world, that the density of gold was…