Between the mouths of the Blackwater and the Colne, on the east coast of Essex, lies an extensive marshy tract veined and freckled in every part with water. It is a wide waste of debatable ground contested by sea and land, subject to incessant incursions from the former, but stubbornly maintained by the latter. At high tide the appearance is that of a vast surface of moss or Sargasso weed floating...