Wordsworth's claim that his vision of London is the best on earth is clearly an exaggeration, not to mention impossible to verify. But it's an innocent exaggeration, one that puts us "in the moment" of his passing experience. It's really not much different from an expression that many people use all the time nowadays: saying that such-and-such is the most fun ever, or the best movie ever, or the most awkward party ever. In other words, Wordsworth talks a little like a contemporary teenager.
- Line 1: Earth, you really outdid yourself on this one. The claim that no sight is more beautiful than the view from Westminster Bridge is a case of hyperbole, or exaggeration.
- Line 2: The word "dull" suggests a contrast with a knife or some other sharp object. In the implicit metaphor, the dull person's soul has been worn down by time and experience.
- Line 3: To say that something is "touching in its majesty" is almost a paradox, a contradiction in terms. A touching sight is intimate and personal, while a majestic one is grand and public. With this phrase, Wordsworth comes close to capturing the indescribable feeling of familiarity and distance all at once.
- Lines 9-11: Lines 9 and 11 have a parallel structure, in which he claims that the effect of the morning light on London creates a beauty that has "never" been experienced before. As in the first line, these claims are hyperboles.