Among the many thousands of things that I have never been able to understand, one in particular stands out. That is the question of who was the first person who stood by a pile of sand and said, “You know, I bet if we took some of this and mixed it with a little potash and heated it, we could make a material that would be solid and yet transparent. We could call it glass.” Call me obtuse, but you could stand me on a beach till the end of time and never would it occur to me to try to make it into windows.