Red Ochre
On Uncertain Principles, Chad Orzel counts up toward the birthday of that most holy of men: Sir Isaac Newton. Each day Orzel will (hopefully) unveil a new gem that didn't make it into his exciting new book. On Day 1, Chad wrote about the apocryphal moment of inspiration—in a bathtub—that led the Greek polymath Archimedes to first exclaim "Eureka!" And for Day 2, Orzel considers the scientific origin of art among prehistoric peoples in southern Africa. He writes, "The pigment-grinding process wasn’t a simple thing that might happen by accident, but a multi-step process, involving grinding then…