Question

Dull would he be of soul who could pass by . figure of speech​

Answer 1

This line is from the Poem "Composed Upon Westminster Bridge, September 3, 1802" by William Wordsworth. The complete line in the poem is as below;

'Dull would he be of soul who could pass by

A sight so touching in its majesty'

In this poem the poet is describing the beauty of the Westminster Bridge and the beautiful lights and sights of London from there. The figure of speech here is ‘Hyperbole’.  

A Hyperbole is a very common figure of speech used for the sake of emphasis. It is mostly an obvious and deliberate exaggeration and not intended to be taken literally. For example, You might say "I'm starving", when you are hungry.

Here, the poet describes that the person who could pass by Westminster Bridge without being amazed by the beauty and staying longer to soak it all in, would need to be someone with a very dull soul, indicating someone who cannot be a lively person who appreciates these beautiful moments.