The sun arose, i saw it [the pond] throwing off its nightly clothing of mist, and here and there, by degrees, its soft ripples or its smooth reflecting surface was revealed, while the mists, like ghosts, were stealthily withdrawing in every direction into the woods, as at the breaking up of some nocturnal conventicle [secret meeting]. in the excerpt, thoreau uses imagery to describe

How the water looks during a is the use of vocabulary and 'flowery' words to describe something in such detail so that you can imagine it.

In this excerpt, thoreau uses imaginary to describe how the fog starts to rise slowly from the surface (of the pound). it seems that he is connected with nature and he is able to feel it. he uses to remind the reader how we easily forget to experience the moment because we are in constant movement. the mists were seen as "ghosts" that starts to cover everything and it is difficult to see.