Let your walks now be a little more adventurous; ascend the hills. If, about the last of October, you ascend any hill in the outskirts of our town, and probably of yours, and look over the forest, you may see--well, what I have endeavored to describe. All this you surely _will_ see, and much more, if you are prepared to see it,--if you _look_ for it. Otherwise, regular and universal as this phenomenon is, whether you stand on the hill-top or in the hollow, you will think for threescore years and ten that all the wood is, at this season, sear and brown. Objects are concealed from our view, not so much because they are out of the course of our visual ray as because we do not bring our minds and eyes to bear on them; for there is no power to see in the eye itself, any more than in any other jelly. We do not realize how far and widely, or how near and narrowly, we are to look. The greater part of the phenomena of Nature are for this reason concealed from us all our lives. The gardener sees only the gardener's garden. Here, too, as in political economy, the supply answers to the demand. Nature does not cast pearls before swine. There is just as much beauty visible to us in the landscape as we are prepared to appreciate,--not a grain more. The actual objects which one man will see from a particular hill-top are just as different from those which another will see as the beholders are different The Scarlet Oak must, in a sense, be in your eye when you go forth. We cannot see anything until we are possessed with the idea of it, take it into our heads,--and then we can hardly see anything else. In my botanical rambles, I find, that, first, the idea, or image, of a plant occupies my thoughts, though it may seem very foreign to this locality,--no nearer than Hudson's Bay,--and for some weeks or months I go thinking of it, and expecting it unconsciously, and at length I surely see it. This is the history of my finding a score or more of rare plants, which I could name. A man sees only what concerns him. A botanist absorbed in the study of grasses does not distinguish the grandest Pasture Oaks. He, as it were, tramples down Oaks unwittingly in his walk, or at most sees only their shadows. I have found that it required a different intention of the eye, in the same locality, to see different plants, even when they were closely allied, as _Juncaceoe_ and _Gramineoe_: when I was looking for the former, I did not see the latter in the midst of them. How much more, then, it requires different intentions of the eye and of the mind to attend to different departments of knowledge! How differently the poet and the naturalist look at objects!