Noting how one eye seconds and reinforces the other, I have often amused myself by wondering what the effect would be if one could go on opening eye after eye, to the number, say, of a dozen or more. What would he see? Perhaps not the invisible--not the odors of flowers or the fever germs in the air--not the infinitely small of the microscope or the infinitely distant of the telescope. This would require not so much more eyes as an eye constructed with more and different lenses; but would he not see with augmented power within the natural limits of vision? At any rate, some persons seem to have opened more eyes than others, they see with such force and distinctness; their vision penetrates the tangle and obscurity where that of others fails, like a spent or impotent bullet. How many eyes did Gilbert White open? how many did Henry Thoreau? how many did Audubon? how many does the hunter, matching his sight against the keen and alert senses of a deer, or a moose, or a fox, or a wolf? Not outward eyes, but inward. We open another eye whenever we see beyond the first general features or outlines of things--whenever we grasp the special details and characteristic markings that this mask covers. Science confers new powers of vision. Whenever you have learned to discriminate the birds, or the plants, or the geological features of a country, it is as if new and keener eyes were added. Of course one must not only see sharply, but read aright what he sees. The facts in the life of nature that are transpiring about us are like written words that the observer is to arrange into sentences. Or, the writing is a cipher and he must furnish the key. A female oriole was one day observed very much preoccupied under a shed where the refuse from the horse stable was thrown. She hopped about among the barn fowls, scolding them sharply when they came too near her. The stable, dark and cavernous, was just beyond. The bird, not finding what she wanted outside, boldly ventured into the stable, and was presently captured by the farmer. What did she want? was the query. What but a horse-hair for her nest, which was in an apple-tree near by? and she was so bent on having one that I have no doubt she would have tweaked one out of the horse's tail had he been in the stable. Later in the season I examined her nest, and found it sewed through and through with several long horse-hairs, so that the bird persisted in her search till the hair was found.