O Melancholy!--such thy magic power,That to the soul these dreams are often sweet,And soothe the pensive visionary mind! (12-14)
The speaker finally addresses melancholy directly here in the last few lines. She says that melancholy actually soothes her mind and soul when she's feeling pensive. Kind of like how we like to listen to sad songs on repeat when we're feeling mopey. The speaker doesn't have an iPod, so she just goes down to the river and listens to the sighing of the wind.