Samuel Clemens, age 15 holding metal type in a composing stick that spells out his first name. As a daguerreotype, whose creation involved no intermediate negative, the image is laterally reversed. Hence the type, which, in actuality, was backward, is readable, though Twain himself is flipped.
(From l. to r.) American Civil War correspondent and author George Alfred Townsend, Mark Twain and David Gray, editor of the rival Buffalo Courier