No More Learning

I know not if I shape
These things with accurate similitude
From visible objects, for but dimly now,
Less vivid than a half-forgotten dream,
The memory of that mental excellence
Comes o'er me, and it may be I entwine
The indecision of my present mind
With its past clearness, yet it seems to me
As even then the torrent of quick thought
          me from the nature of itself
With its own fleetness.