"The--I shall have to ask Arden about those later, as I must confess I am not familiar with them myself," Lydia said. "I've been here a year and a half now and so much still seems new! But no, I don't expect you should know about any of those things, aside from the clothes and the shoes. Electricity is--it's not magic, but I don't have the first clue how it works, so it's like a sort of magic that powers all sorts of things, like lights you can turn on with a switch on the wall, or a box that keeps food cold so it doesn't spoil. It has to do with lightning somehow, I believe. And plumbing is a system of pipes that brings water into buildings, so you don't have to carry it from a well or a pump." They did have wells and pumps in the middle ages, right? Lydia was unclear on such things. "It can even be hot! Right from the wall!"