ABSTRACT
Let's start with prisms. We all know that Isaac Newton took a prism and used it to separate white light into bands of light of different colors (what we call a spectrum). And so had thousands of time-wasting fellows in the centuries since someone first picked up a piece of burned sand out of the campfire. But old Isaac did something unusual. He took a second prism and recombined the rainbow back into white light. And then he did something unprecedented: Instead of saying, “Oh, how pretty!,” he contemplated, he observed, and he wrote about it.
