Sarah and I pause to rest our feet at a burrito bar midafternoon after touring the National Gallery, where we stood transfixed beside Holbein’s “The Ambassadors” and Salvator Rosa’s “Witches at Their Incantations.” Names come tumbling into consciousness, forming pathways for future research: John Michell, Gerald Gardner, Jeff Nuttall, Count Stenbock, Ithell Colquhoun.
