No More Learning

And the fire, likewise,
Will melt the copper and will fuse the gold,
But hides and flesh it shrivels up and shrinks.
The water hardens the iron just off the fire,
But hides and flesh (made hard by heat) it softens.
The oleaster-tree as much delights
The bearded she-goats, verily as though
'Twere nectar-steeped and shed ambrosia;
Than which is naught that burgeons into leaf
More bitter food for man. A hog draws back
For marjoram oil, and every unguent fears
Fierce poison these unto the bristled hogs,
Yet unto us from time to time they seem,
As 'twere, to give new life. But, contrariwise,
Though unto us the mire be filth most foul,
To hogs that mire doth so delightsome seem
That they with wallowing from belly to back
Are never cloyed.

A point remains, besides,
Which best it seems to tell of, ere I go
To telling of the fact at hand itself.
Since to the varied things assigned be
The many pores, those pores must be diverse
In nature one from other, and each have
Its very shape, its own direction fixed.
And so, indeed, in breathing creatures be
The several senses, of which each takes in
Unto itself, in its own fashion ever,
Its own peculiar object. For we mark
How sounds do into one place penetrate,
Into another flavours of all juice,
And savour of smell into a third. Moreover,
One sort through rocks we see to seep, and, lo,
One sort to pass through wood, another still
Through gold, and others to go out and off
Through silver and through glass. For we do see
Through some pores form-and-look of things to flow,
Through others heat to go, and some things still
To speedier pass than others through same pores.
Of verity, the nature of these same paths,
Varying in many modes (as aforesaid)
Because of unlike nature and warp and woof
Of cosmic things, constrains it so to be.

Wherefore, since all these matters now have been
Established and settled well for us
As premises prepared, for what remains
'Twill not be hard to render clear account
By means of these, and the whole cause reveal
Whereby the magnet lures the strength of iron.
First, stream there must from off the lode-stone seeds
Innumerable, a very tide, which smites
By blows that air asunder lying betwixt
The stone and iron. And when is emptied out
This space, and a large place between the two
Is made a void, forthwith the primal germs
Of iron, headlong slipping, fall conjoined
Into the vacuum, and the ring itself
By reason thereof doth follow after and go
Thuswise with all its body.
And naught there is
That of its own primordial elements
More thoroughly knit or tighter linked coheres
Than nature and cold roughness of stout iron.
Wherefore, 'tis less a marvel what I said,
That from such elements no bodies can
From out the iron collect in larger throng
And be into the vacuum borne along,
Without the ring itself do follow after.
And this it does, and followeth on until
'Thath reached the stone itself and cleaved to it
By links invisible. Moreover, likewise,
The motion's assisted by a thing of aid
(Whereby the process easier becomes),--
Namely, by this: as soon as rarer grows
That air in front of the ring, and space between
Is emptied more and made a void, forthwith
It happens all the air that lies behind
Conveys it onward, pushing from the rear.
For ever doth the circumambient air
Drub things unmoved, but here it pushes forth
The iron, because upon one side the space
Lies void and thus receives the iron in.
This air, whereof I am reminding thee,
Winding athrough the iron's abundant pores
So subtly into the tiny parts thereof,
Shoves it and pushes, as wind the ship and sails.
The same doth happen in all directions forth:
From whatso side a space is made a void,
Whether from crosswise or above, forthwith
The neighbour particles are borne along
Into the vacuum; for of verity,
They're set a-going by poundings from elsewhere,
Nor by themselves of own accord can they
Rise upwards into the air. Again, all things
Must in their framework hold some air, because
They are of framework porous, and the air
Encompasses and borders on all things.
Thus, then, this air in iron so deeply stored
Is tossed evermore in vexed motion,
And therefore drubs upon the ring sans doubt
And shakes it up inside. . . .

*****

In sooth, that ring is thither borne along
To where 'thas once plunged headlong--thither, lo,
Unto the void whereto it took its start.

It happens, too, at times that nature of iron
Shrinks from this stone away, accustomed
By turns to flee and follow. Yea, I've seen
Those Samothracian iron rings leap up,
And iron filings in the brazen bowls
Seethe furiously, when underneath was set
The magnet stone. So strongly iron seems
To crave to flee that rock.