would it matter if this new lamp upon my desk were to go out? But if that second-hand lamp suddenly sputtered out, it would be the end of everybody! And now, like the image that the photographer sees appearing on the sensitive plate as he washes it in the developer, the principle underlying this matter begins to emerge. If I want a very small thing—a pen or a pencil—it never occurs to me to go to a second-hand store; I send direct to the stationer’s, and buy a new one. If I want a medium-sized thing