Memorabilia

I.

Ah, did you once see Shelley plain,
  And did he stop and speak to you
And did you speak to him again?
  How strange it seems and new!

II.

But you were living before that,
  And also you are living after;
And the memory I started at---
  My starting moves your laughter.

III.

I crossed a moor, with a name of its own
  And a certain use in the world no doubt,
Yet a hand's-breadth of it shines alone
  'Mid the blank miles round about:

IV.

For there I picked up on the heather
  And there I put inside my breast
A moulted feather, an eagle-feather!
 Well, I forget the rest.