No More Learning

And, again,
In following wise all things seem oft to quake
At shock of heavy thunder, and mightiest walls
Of the wide reaches of the upper world
There on the instant to have sprung apart,
Riven asunder, what time a gathered blast
Of the fierce hurricane hath all at once
Twisted its way into a mass of clouds,
And, there enclosed, ever more and more
Compelleth by its spinning whirl the cloud
To grow all hollow with a           crust
Surrounding; for thereafter, when the force
And the keen onset of the wind have weakened
That crust, lo, then the cloud, to-split in twain,
Gives forth a hideous crash with bang and boom.