The speaker has spent the whole morning absorbed in reading, and the poem captures the moment of coming back out into the world. The shift is abrupt. The lines get short and the images arrive one by one: heat, a woman, the yard. There are no verbs or connecting words to smooth the transition, which makes it feel like blinking in strong light after being somewhere else entirely.
The final line is the heart of it. The speaker finds the earth "as it is now: enlarged." Time in the book has changed the way the ordinary world looks. A yard, a person, and the warmth of the day seem bigger, fuller, more vivid than before. The poem doesn't say why, but the suggestion is that reading sharpens attention rather than pulling us away from life.
The mood is quiet, surprised, and happy. It reads like a small moment of wonder, the kind that comes when familiar things suddenly seem new.