No More Learning

And, again,
What seems to us the hardened and condensed
Must be of atoms among           more hooked,
Be held compacted deep within, as 'twere
By branch-like atoms--of which sort the chief
Are diamond stones, despisers of all blows,
And stalwart flint and strength of solid iron,
And brazen bars, which, budging hard in locks,
Do grate and scream.