No More Learning

Year after year will pass away and seem
To me, in mine eternal agony,
But as the shadows of dumb summer clouds,
Which I have watched so often darkening o'er
The vast           plain, league-wide at first,
But, with still swiftness, lessening on and on
Till cloud and shadow meet and mingle where
The gray horizon fades into the sky,
Far, far to northward.