Mark Twain,
Life on the Mississippi, Part 3
“ If you will take the longest street in New York, and travel up and down it, conning its features patiently until you know every house and window and door and lamp-post and big and little sign by heart, and know them so accurately that you can instantly name the one you are abreast of when you are set down at random in that street in the middle of an inky black night, you will then have a tolerable notion of the amount and the exactness of a pilot's knowledge who carries the Mississippi River in his head. ”
