There is one note on the page that seems disconnected from everything else. It is a recipe for making blond-brown hair dye: “To make hair tawny, take nuts and boil them in lye and immerse the comb in it, then comb the hair and let it dry in the sun.” This may have been a notation in preparation for a court pageant. But it is more likely, I think, that the recipe is a rare intimate jotting. Leonardo was deep into his thirties by now. Perhaps he was resisting going gray.