« PreviousContinue »
the right or the left, according to our wishes. There are six muscles, or little instruments which regulate its motions.
If any of these should be hurt, Father, what should we do?
Our sight, of course, would be very imperfect. I have read the works of an au thor, who says, that he knew a gentleman, who enjoyed good general health, but the two little muscles which lift up the eye-lid had lost their power of action; so, when he looked at any object, he was obliged to push up his eye-lids with his hands. How much are we indebted every moment to the goodness of God, for preserving the health of the most inconsiderable parts of the human frame.
How thankful we ought to be when we are quite well! But did you not say, that the eye-grows smaller or larger in different situations?
The pupil, or the middle of the eye, does expand or contract, according to the degree of light which there is around us. The other evening, when we were enjoying the twilight in the parlour, and John brought in the candles, don't you recollect, that you said that the light pained you?
Yes, Father; but it was unpleasant only when the candles were first brought in. True; and the reason was, the pupil of
the eye soon adjusted itself to the light which was around you; and then you be
Was that it, Father? I did not think how it was.
I suppose not. Many persons who are grown up to manhood, little think, how wonderful the different parts of the human frame are.
When the little gnat got into cousin Charles' eye, you know, Father how much he suffered: and yet the light is always coming into them, and it does not hurt us.
So it is; the light not only does not pain us, but it affords us great pleasure. The fly however, which pained Charles so much, though it was but a small one, was more than a million times bigger than a ray of light.
I cannot think how it is, that the objects we see are really drawn on the eye; it seems impossible; but did you not say so, Father?
I did. There is spread all over the bottom of the eye a delicate net-work; it consists of a beautiful expansion of the optic nerve. Impressions of things are conveyed by this nerve to the brain; and the rays of light pass through the pupil, and paint the figure of any object which we see upon it.
You showed us this the other day, when
the butcher brought the eye of a bullock; you cut off the three coats from the back of it, and held it up to the window; and the figure of the casement was on the paper you held behind it.
But it was upside down, Father: and are objects drawn the wrong way upwards on our eyes?
So you see, it appears, Frank.
How is it, then, that we never see things upside down?
It is difficult altogether to account for it. There are very many things, Frank, which no one fully knows: the works of the great God are unsearchable. But look around
you, what do you see?
St. Paul's, and the Thames, and the fine bridges over it, and the shipping, and houses innumerable; I see the whole of London, and the country all around it, to a vast distance.
You do; the view here comprehends an area of some hundreds of miles; it is a sublime prospect.
And how delightfully it glitters with the beautiful rays of the setting sun!
You said one day, Father, that we could not see any object, unless the rays of light flowed from it to our eyes.
Of course you cannot.
Do the rays of the sun then, come to my eyes from St. Paul's, and from the Thames, and from all the innumerable objects which I now behold?
How wonderful! But the same rays of light which enter my eyes, do not enter the eyes of the gentleman a little beyond us, though he is looking at the same prospect, do they?
O no; thousands of millions of rays are every instant sent forth from St. Paul's to all the multitudes of persons who are gazing on it. *
And yet, Father, there is no confusion. True, there is not; if a thousand persons were here, every eye would see St. Paul's distinctly.
But how is it, that rays from so many thousand thousand objects can find admission through the small pupil of the eye?
I cannot altogether tell you.
You said Father, that you would tell me something wonderful, and this is truly so.
There is, however, a more astonishing circumstance, Frank, which you have not yet noticed.
What is that, Father?
It is, that all this vast landscape, that all this immense assemblage of objects, should be all accurately drawn on the net-work at the bottom of the eye,
And is it so, Father? This is wonderful! The painter, who drew the miniature of your Mother, is a man of great genius and talent; but do you think, that he could draw a tenth part of this magnificent landscape, with all its brilliant coloring, on at space not larger than the nail of my thumb? Impossible!
Sec, what impossibilities the adorable. Creator is bringing to pass every moment! Here is the finger of God! Unspeakably delicate must be the strokes of that pencil which is held by the divine hand!
They must, indeed!
And there is another circumstance, which is very remarkable; it is, the ease with which the eye adjusts itself to behold objects, whether they are near, or whether they are distant. It is in vain that we should use the telescope, to examine the fine parts of a leaf, or flower, or any thing that is near at hand; and equally vain would it be, to employ the microscope, to command the most distant part of this magnificent prospect. It would.
But the eye adjusts itself in an instant, to any distance. It examines objects which are a few inches us, lik the microscope; and, when we wish it, it becomes a telescope, and brings to us an accurate likeness of the distant landscape.