It was a September evening and not yet seven o'clock, but the day had been a dreary one, and a dense drizzly fog lay low upon the great city. Mud-coloured clouds drooped sadly over the muddy streets. Down the Strand the lamps were but misty splotches of diffused light which threw a feeble circular glimmer upon the slimy pavement. The yellow glare from the shop-windows steamed out into the steamy, vaporous air and threw a murky, shifting radiance across the crowded thoroughfare. There was, to my mind, something eerie and ghostlike in the endless procession of faces which flitted across these narrow bars of light - sad faces and glad, haggard and merry. Like all humankind, they flitted from the gloom into the light and so back into the gloom once more. I am not subject to impressions, but the dull, heavy evening, with the strange business upon which we were engaged, combined to make me nervous and depressed. I could see from Miss Morstan's manner that she was suffering from the same feeling.
-Sir Arthur Conan Doyle, "The Sign of Four"