"Life is short," said Leibniz, and looked Eliza up and down. It was a blunt allusion to smallpox. "I can stand in the aisle of the Nikolaikirche for two hours and try to get it across to you in words, and at the end of it you’ll only say, ‘I must see it with my own eyes.’ Or I can take you on a five-minute walk and see the thing settled."