Get out the microscope, because we’re going through this poem line-by-line.
Line 1
To him who in the love of Nature holds
- The first line of this poem is confusing all by itself, so read through it to the middle of the third line – that’s where the first idea ends (at the semicolon after "language"). Now let’s go back to line 1.
- Here the speaker is introducing us to a certain kind of guy who loves nature.
Line 2
Communion with her visible forms, she speaks
- This guy has an almost holy relationship with nature. He "holds communion" (like you would do in a church) with things like rocks and trees and rivers (those are examples of "visible forms" of nature). In these moments of communion nature actually "speaks" to this guy.
- Nature is the "she" mentioned at the end of the line. That’s an example of personification, a pretty common poetic trick.
- (We’ll go along with Bryant and use the capital letter "N" for Nature, because in this case she’s more like a person than a thing).
Lines 3-5
A various language; for his gayer hours
She has a voice of gladness, and a smile
And eloquence of beauty, and she glides
- Nature talks to her lover in different ways, depending on the way he’s feeling. When he is feeling happy (in "his gayer hours") Nature smiles, and speaks to him happily ("with a voice of gladness"). In these moments, she has the "eloquence" (smooth and lovely speech) "of beauty" (line 5).
Lines 6-8
Into his darker musings, with a mild
And healing sympathy, that steals away
Their sharpness, ere he is aware. When thoughts
- Sometimes the nature lover is feeling mopey and is brooding over depressing thoughts. Then Nature "glides" in and makes him feel better.
- In these moments, Nature treats him with gentle sympathy, which heals him. She takes away the pain ("sharpness") of his thoughts before he even realizes it. Basically, when this guy’s feeling lousy, Nature fixes him up. She might even bake him some chocolate-chip cookies.