After the gradual cessation of all sound and movement on the faithful river, only the ringing of ships' bells is heard, mysterious and muffled in the white vapour from London Bridge right down to the Nore, for miles and miles in a decrescendo tinkling, to where the estuary broadens out into the North Sea, and the anchored ships lie scattered thinly in the shrouded channels between the sand-banks of the Thames' mouth.