Pictures of Grant sitting for Mathew Brady remind me of this story:
To secure a new photograph of the general, Stanton (who now knew what Grant looked like) hustled the general down to Mathew Brady's studio on the Seventh Street and Pennsylvania Avenue. Grant took up his position in front of the camera, his face barely revealing any emotion, and waited patiently. It was midafternoon, and Brady directed his assistant to go up anon the roof to uncover the skylight. The assistant slipped; the skylight shattered. As Brady and Stanton watched in horror, shards of glass, each some two inches thick, cascaded around the general, each fragment potentially damaging if not lethal. As the pieces hit the floor, the two men stared, astonished , at Grant, who sat unmoved and unhurt. He glanced up at the ceiling, then back at the cameras, as if nothing noteworthy had happened. Brady later called it "the most remarkable display of nerve I ever witnessed"; and excited Stanton, fearing rumors of an assassination attempt, swore the photographer to secrecy. Then the session went on. Ulysses S. Grant, Triumph Over Adversity, 1822-1865, Brooks D. Simpson, [pg 266]