In this Petrarchan sonnet, Wordsworth describes the view of London from Westminster Bridge on a quiet morning in 1802 before the usually bustling city is awake and moving. When Wordsworth notes that the houses of the city "seem asleep," he is referring to the fact that they are unmoving, untroubled, and do not seem to look the way they usually look during the day, when the streets are filled with people, and there is business being conducted around the houses.
Wordsworth describes the quietude of the morning as being akin to a "garment" which lies over the city. This is obviously unusual and an unusual view of London for the poet, who feels a "calm" which is extremely "deep" in being able to witness such a sight. He notes that the air of the city, which is usually rendered dark with industry, is actually "smokeless" at this point in time, as if the factories, like the houses, are also asleep and thus unable to pump their usual smoke and smog into the atmosphere. Viewed from this vantage point, although London is one of the largest and busiest cities in the world at this point in time, the city appears to be what it is: a habitat that is part of a wider natural setting, giving way at its borders to the sky and to the fields around.