I was showing my house to some visitors from LA last week, and Brooke noticed the jams and preserves lined up at the top of my pantry. “Do you know someone who makes those for you?” she asked. “I did that,” I said. “Really?” she seemed surprised, as if she’d never known anyone who made jam. “If I’m here next summer will you show me how?” “Sure,” I told her. “It’s easy.” It got me thinking about skills that used to be considered perfectly ordinary: making jam, running up a skirt on a sewing machine, growing some of your own…