Whitman: Does the daylight astonish? (2 days to DR. BIRD)

One of the key quotes from Dr. Bird's Advice for Sad Poets can be found in this passage.

"Do you guess I have some intricate purpose?
Well I have, for the Fourth-month showers have, and the mica on the side of a rock has.

Do you take it I would astonish?
Does the daylight astonish? does the early redstart twittering through the woods?
Do I astonish more than they?

This hour I tell things in confidence,
I might not tell everybody, but I will tell you."