The aspect of London along the Thames, below Bridge, as it is called, is by no means so impressive as it ought to be, considering what peculiar advantages are offered for the display of grand and stately architecture by the passage of a river through the midst of a great city. It seems, indeed, as if the heart of London had been cleft open for the mere purpose of showing how rotten and drearily mean it had become. The shore is lined with the shabbiest, blackest, and ugliest buildings that can be imagined, decayed warehouses with blind windows, and wharves that look ruinous; insomuch that, had I known nothing more of the world’s metropolis, I might have fancied that it had already experienced the down-fall which I have heard commercial and financial prophets predict for it, within the century. And the muddy tide of the Thames, reflecting nothing, and hiding a million of unclean secrets within its breast,—a sort of guilty conscience, as it were, unwholesome with the rivulets of sin that constantly flow into it,—is just the dismal stream to glide by such a city. The surface, to be sure, displays no lack of activity, being fretted by the passage of a hundred steamers and covered with a good deal of shipping, but mostly of a clumsier build than I had been accustomed to see in the Mersey: a fact which I complacently attributed to the smaller number of American clippers in the Thames, and the less prevalent influence of American example in refining away the broad-bottomed capacity of the old Dutch or English models. About midway between Greenwich and London Bridge, at a rude landing-place on the left bank of the river, the steamer rings its bell and makes a momentary pause in front of a large circular structure, where it may be worth our while to scramble ashore. It indicates the locality of one of those prodigious practical blunders that would supply John Bull with a topic of inexhaustible ridicule, if his cousin Jonathan had committed them, but of which he himself perpetrates two to our one in the mere wantonness of wealth that lacks better employment. The circular building covers the entrance to the Thames Tunnel, and is surmounted by a dome of glass, so as to throw daylight down into