"They were shrouded in the fog which made the night heavy, opaque, and nauseous. It was like a pestilential cloud dropped on the earth. It could be seen swirling past the gas-lights, which it seemed to put out at intervals. The pavement was as slippery as on a frosty night after rain, and all sorts of evil smells seemed to come up from the bowels of the houses—the stench of cellars, drains, sewers, squalid kitchens—to mingle with the horrible savour of this wandering fog."