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"A ship" says Reid, requires a different trim for every variation of the direction and strength of the wind; and if we may be allowed to borrow that word, the eyes require a different trim for every degree of light. and for every variation of the distance of the object, while it is within certain limits. The eyes are trimmed for a particular object, by contracting certain muscles, and relaxing others; as the ship is trimmed for a particular wind, by drawing certain ropes and slackening others. The sailor learns the trim of his ship, as we learn the trim of our eyes, by experience. A ship, although the noblest machine that human art can boast, is far inferior to the eye in this respect, that it requires art and ingenuity to navigate her; and a sailor must know what ropes he must pull, and what he must slacken, to fit her to a particular wind: but with such superior wisdom is the fabric of the eye, and the principles of its motion contrived, that it requires no art or ingenuity to see by it. Even that part of vision which is got by experience, is attained by idiots. We need not know what muscles we are to contract, and what we are to relax, in order to fit the eye to a particular distance of the object."
The more, Father, you talk about the eye, the more surprising it appears. I never be fore thought of all this.
I suppose not, Frank; and this is the case with many people who are much older than you are. I have, however, but just entered on the subject. I have said nothing on the "parallel motion of the eyes; by which, when one eye is turned to the right or left, upwards or downwards, or straight forwards, the other always goes along with it in the same direction. We see plainly, when both eyes are open, that they are always turned the same way, as if both were acted on by the same motive, force; and if one eye is shut, and the hand laid upon it, while the other turns various ways, we feel the eye that is shut turn at the same time, and that whether we will or not. What makes this surprising is, that all anatomists say, that the muscles which move the two eyes, and the nerves which serve these muscles, are entirely unconnected. It would be thought very surprising, to see a man, who from his birth, never moved one arm, without moving the other in the same manner, so as to keep them always parallel: yet it would not be more difficult to find the cause of such motion of the arms, than it is to find the cause of the parallel motion of the eyes, which is perfectly similar.”
But, Father, I wonder you don't know how this is; you know almost every thing.
You are very much mistaken, Frank; we
may reasonably expect many of the works of the great God to be far beyond our com- prehension.
It is a very pleasant thing to have good eyes; and, as you often say, to use them as we ought.
Yes, Frank, to use them as we ought, is indeed a continual feast.
It is said in the Psalms, Father, that we "are fearfully and wonderfully made."
Indeed we are; every part of the human frame displays the handy work of the Crea
And his goodness too, Father.
Yes, he must be good, who gives me so much enjoyment every time I open my eyes, and gaze around me. How much the blind are to be pitied!
It is surprising, though, Father, how blind Betty in the cottage on the common finds every thing around her by feeling.
Yet how superior is sight! How could a blind man acquire an accurate knowledge of such a building as St. Paul's, by touch ?Or how could he form an accurate judgment of this magnificent landscape? A blind man, by feeling, could never find a path through the immeasurable ocean, or sail round the globe, or trace out its shape, or survey its kingdoms; much less could he examine the heavens, and measure the distances of the stars.
This would indeed be impossible, by feeling, Father; the arms which should reach to the stars must be very long.
By the eye, too, we may often give a very shrewd guess, as to the real temper and disposition of our fellow creatures; deceit is often unmasked by the eye; a blind person would be lost here.
It is wonderful, Father, to think of the different kind of eyes. Now there is the little mite, we saw through the microscope, he has eyes, but he cannot see farther than a little part of an inch before him.
True; and perhaps Newton is but a mite contrasted with an angel.
Should we be so happy as to reach heav en, and nothing, but our wilful rebellion against the good God can shut us out of it, -perhaps, our organs of vision will be, in some unknown and inconceivable way, immensely superior to what they now are.
That is a delightful thought, Father; I should like to have eyes by which I could sce the people in the moon, and all the fine landscapes there. Do you think that this will ever be the case?
It is not impossible, that in a better state, we may be enabled to see distinctly much farther than the moon. It is said in the Scriptures, "Eye hath not seen, nor hath