The next afternoon, when Catherine found her mother at leisure, she came and stood close by her, and looked in her face for some time.

“What are you looking at me for, so steadily?” said Mrs. Nelson.

“I am trying to see the pictures in your eyes, mother; and don’t you remember, that you said you would tell me more about these curious little painters, as you call them? Is it only that small dark spot in the middle of your eye that sees?”

“That little place, my dear, is a sort of window, which lets in the light that makes the picture upon the back part of the eye. It is called the pupil, and it is what is meant by ‘the apple,’ which you recollect being puzzled with in the Psalm that you read for your Sunday lesson. Do you remember it?” After a while, Catherine said, “Oh, yes;” and repeated this verse, “Keep me under the apple of thine eye, hide me under the shadow of thy wings.”

“By this little round window the light enters the eye, and passes through to the back part of it, and represents there, upon what is called the retina, everything that we see. So you perceive that if anything happens to the pupil of the eye, no light can enter it, and we should see nothing of all this beautiful and glorious world around us; we should be in perpetual darkness.”—“And now, mother, I understand the Psalm; for it is necessary that these two little windows should be kept very safe, as safe as we pray that God would keep us. But is that a little hole in the eye, mother?”

“No, my dear, this precious part of the eye has a covering over it like the chrystal of a watch; this is properly called the cornea, a Latin word that means like horn, because it resembles thin horn that the light can shine through,—as you may ascertain by asking the cook to show you a fish’s eye, and looking at this part.”

“And is the eye all hollow, mother? or what is between the pupil and the place on the back part of the eye where the picture is painted, that you called—I forget what you called it, mother?”

“The retina, my dear, from a Latin word that means anything by which another thing is held or retained, as this part of the eye holds or retains the picture of things. You ask me what is between the pupil and the retina. There are in the eye three different substances, called humours, all transparent. A transparent substance means anything that can be seen through. The first one, directly back of the pupil, is called the acqueous, from a Latin word, that means watery: it is a thin liquid, like water. The second, behind that, is called the crystalline humour, from its clearness and brightness. It is formed like the glasses they use in telescopes, and is fastened at the edge by the delicate transparent substance that covers it, called a membrane. The one beyond this, and next the retina, is called the vitreous humour, from its resemblance to glass. All these substances assist in forming the images of objects on the back of the eye; but you are not old enough to understand how, at present, my child.”

“Then, mother,” said Catherine, “our eyes are as curious as grandfather’s telescope, or as the camera obscura, that he gave us to see pictures with.”

“They are far more curious my dear; and it is by imitating the eye that they can make them so well. I remember, Catherine, when your grandfather sent that camera obscura to you the other day, and your father showed you the pictures in it, that you and Lucy and James capered about the room with joy, saying, ‘Oh, how good grandfather is to give us such a beautiful thing!’—and now, my dear, when you go into a garden and dance with joy at the sight of the flowers; when you look up with so much wonder and delight at the beautiful moon sailing through the clouds, and at the bright twinkling stars; when, after having been even one day away from your father and mother, you feel so happy at looking in our faces, and reading in them our love for you,—of whose goodness ought you to think? Who has given you eyes to see all these delightful things? Whom should you then love? Of whom then should you speak, and say, ‘Oh, how good He is?’”

Catherine felt and understood what her mother said, and answered her, that it was God.

“I have yet much more, my dear,” said her mother, “to tell you about the eyes, that is very wonderful. This beautiful little round window grows larger and smaller as you want more or less light. When there is a great light, it contracts so as to take in but little; and when the light is faint, it becomes nearly twice as large, so as to take in more.”

“Why, mother,” said Catherine, “how can that be?”

“Shut the shutter,” said Mrs. Nelson, “and then look in my eye.” She did so; and she saw the pupil of her mother’s eye grow larger and larger. “Now open it,” said her mother. She did so, and it gradually became smaller. “Oh, it is very curious,” said Catherine. “But, mother, is not that pretty rim round the pupil of any use?”

“That is what it called the iris,” answered her mother, “which is the latin name for rainbow, I suppose from some fancied resemblance to it. It is thought that by means of it the pupil of the eye is enlarged or contracted. If you remember, my child, the pain you feel in your eyes when you come from the dark suddenly into the light, you will understand the use of this, and see what a beautiful contrivance it is. In the dark your pupils become very large, so as to catch all the light they can. When the light comes before they have time to grow smaller, they take in more light than they can bear without pain.

“There is another thing that you never thought of. You know that if your eyes were fixed fast, as your ears and nose are, you could only see straight forward, or you would have to keep your head twirling about continually. But the eye is set loose in the head, and surrounded with little muscles, things with which we can turn it up, or down, or in any way, just as we wish. You know how long it takes grandfather to fix his telescope; but our eyes are ready, quicker than we think.

“You perceive, my dear, that this beautiful and curious thing, the eye, is very delicate, and easily injured, and if anything destroys our sight, it is a great calamity, and that the eye ought to be carefully protected. And so you will find that it is. It is placed in a deep socket, surrounded by bone, and lined with something very soft. It shelves over on the upper part, so as to form the eye-bow, which is a great protection to it. It is important that it should be kept clear and bright, and there is a little vessel close to it, full of salt water, called tears, to wash it clean, whenever we open or shut the eye; and there is a little hole in the bone of the nose to carry off the water after it has washed the eye. Then it has a nice cover, which we call the eyelid, with a beautiful fringe on the edge of it to shut the eye up tight, away from the dust and air when we do not want to use it: and which, moves so quick, that it shuts up in an instant if anything touches or alarms the eye. Indeed, it seems to be always employed in watching over and protecting this precious instrument of knowledge.

“There is still another thing, my dear, to be remembered about the eye. It is so made that sight is pleasant to it. The blue sky, the green grass, the flowers, the rainbow, all give it pleasure.

“A baby, you know, loves to look about, though it knows nothing. Our Father in Heaven has made it a great happiness to us merely to open our eyes upon the beautiful world he has made.”

After a short silence, Catherine said to her mother, “You told me that these curious painters, as you call them, drew the pictures of everything in that wonderful book that you described. How is that done, mother?”

“All we know,” answered Mrs. Nelson, “is, that the back part of the eye, where the pictures are painted is connected with the brain, and that by this means we become acquainted with the appearance of things.”

Well Spent Hour.

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