In such a neighborhood, beyond Dockhead in the Borough of Southwark, stands Jacob’s Island, surrounded by a muddy ditch, six or eight feet deep and fifteen or twenty wide when the tide is in, once called Mill Pond, but known in the days of this story as Folly Ditch. It is a creek or inlet from the Thames, and can always be filled at high water by opening the sluices at the Lead Mills from which it took its old name.
Rookeries - slums where prostitutes and criminals lived, overcrowded, unsanitary, gloomy narrow alleyways
