The next notable group of objects is an assemblage of ancient walls, battlements, and turrets, out of the midst of which rises prominently one great square tower, of a grayish hue, bordered with white stone, and having a small turret at each corner of the roof. This central structure is the White Tower, and the whole circuit of ramparts and inclosed edifices constitutes what is known in English history, and still more widely and impressively in English poetry, as the Tower. A crowd of river-craft are generally moored in front of it; but if we look sharply at the right moment under the base of the rampart, we may catch a glimpse of an arched water-entrance, half submerged, past which the Thames glides as indifferently as if it were the mouth of a city-kennel. Nevertheless, it is the Traitor's Gate, a dreary kind of triumphal passage-way, (now supposed to be shut up and barred forever,) through which a multitude of noble and illustrious personages have entered the Tower, and found it a brief resting-place on their way to heaven. Passing it many times, I never observed that anybody glanced at this shadowy and ominous trap-door, save myself. It is well that America exists, if it were only that her vagrant children may be impressed and affected by the historical monuments of England in a degree of which the native inhabitants are evidently incapable. These matters are too familiar, too real, and too hopelessly built in amongst and mixed up with the common objects and affairs of life, to be easily susceptible of imaginative coloring in their minds; and even their poets and romancers feel it a toil, and almost a delusion, to extract poetic material out of what seems embodied poetry itself to an American. An Englishman cares nothing about the Tower, which to us is a haunted castle in dreamland. That honest and excellent gentleman, the late Mr. G.P.R. James, (whose mechanical ability, one might have supposed, would nourish itself by devouring every old stone of such a structure,) once assured me that he had never in his life set eyes upon the Tower, though for years an historic novelist in London.