QUESTION VIII.

Why Old Men Read Best at a Distance.

PLUTARCH, LAMPRIAS, and OTHERS.

To my discourse in the former problem some objection may be drawn from the sense of seeing in old men; for, if they hold a book at a distance, they will read pretty well, nearer they cannot see a letter and this Aeschylus means by these verses:-

Behold from far; for near thou canst not see; A good old scribe thou mayst much sooner be.

And Sophocles more plainly:-

Old men are slow in talk, they hardly hear; Far off they see; but all are blind when near.

And therefore, if old men's organs are more obedient to strong and intense qualities, why, when they read, do they not take the reflection near at hand, but, holding the book a good way off, mix and weaken it by the intervening air, as wine by water?

Some answered, that they did not remove the book to lesson the light, but to receive more rays, and let all the space between the letters and their eyes be filled with lightsome air. Others agreed with those that imagine the rays of vision mix with one another; for since there is a cone stretched between each eye and the object, whose point is in the eye and whose basis is the object, it is probable that for some way each cone extends apart and by itself; but, when the distance increases, they mix and make but one common light; and therefore every object appears single and not two, though it is seen by both eyes at once; for the conjunction of the cones makes these two appearances but one. These things supposed, when old men hold the letters close to their eyes, the cones not being joined, but each apart and by itself, their sight is weak; but when they remove it farther, the two lights being mingled and increased, see better, as a man with both hands can hold that for which either singly is too weak.

But my brother Lamprias, though unacquainted with Hieronymus's notions, gave us another reason. We see, said he, some species that come from the object to the eye, which at their first rise are thick and great; and therefore when near disturb old men, whose eyes are stiff and not easily penetrated; but when they are separated and diffused into the air, the thick obstructing parts are easily removed, and the subtile remainders coming to the eye gently and easily slide into the pores; and so the disturbance being less, the sight is more vigorous and clear. Thus a rose smells most fragrant at a distance; but if you bring it near the nose, it is not so pure and delightful; and the reason is this - many earthy disturbing particles are carried with the smell, and spoil the fragrancy when near, but in a longer passage those are lost, and the pure brisk odor, by reason of its subtility, reaches and acts upon the sense.

But we, according to Plato's opinion, assert that a bright spirit darted from the eye mixes with the light about the object, and those two are perfectly blended into one similar body; now these must be joined in due proportion one to another; for one part ought not wholly to prevail on the other, but both, being proportionally and amicably joined, should agree in one third common power. Now this (whether flux, illuminated spirit, or ray) in old men being very weak, there can be no combination, no mixture with the light about the object; but it must be wholly consumed, unless, by removing the letters from their eyes, they lessen the brightness of the light, so that it comes to the sight not too strong or unmixed, but well proportioned and blended with the other. And this explains that common affection of creatures seeing in the dark; for their eyesight being weak is overcome and darkened by the splendor of the day; because the little light that flows from their eyes cannot be proportionably mixed with the stronger and more numerous beams; but it is proportionable and sufficient for the feeble splendor of the stars, and so can join with it, and cooperate to move the sense.