No More Learning

And this 'tis thine
To know from these examples: soon as clouds
Have first begun to under-pass the sun,
And, as it were, to rend the rays of light
In twain, at once the lower part of them
Is lost entire, and earth is overcast
Where'er the thunderheads are rolled along--
So know thou mayst that things forever need
A fresh replenishment of gleam and glow,
And each effulgence, foremost flashed forth,
          one by one.