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Rh the outlines or visible figures of bodies are so defined, as to be distinguishable one from another? Nor could the eye, in this case, give us any information concerning diversities of distance; for all the various signs of it, enumerated by optical writers, presuppose the antecedent recognition of the bodies around us, as separate objects of perception. It is not therefore surprising, that signs so indispensably subservient to the exercise of our noblest sense, should cease, in early infancy, to attract notice as the subjects of our consciousness; and that afterwards they should present themselves to the imagination rather as qualities of Matter, than as attributes of Mind.

To this reference of the sensation of colour to the external object, I can think of nothing so analogous as the feelings we experience in surveying a library of books. We speak of the volumes piled up on its shelves, as treasures or magazines of the knowledge of past ages; and contemplate them with gratitude and reverence, as inexhaustible sources of instruction and delight to the mind. Even in looking at a page of print or of manuscript, we are apt to say, that the ideas we acquire are received by the sense of sight; and we are scarcely conscious of a metaphor, when we employ this language. On such occasions we seldom recollect, that nothing is perceived by the eye but a multitude of black strokes drawn upon white paper, and that it is our own acquired habits which communicate to these strokes the whole of that significancy whereby they are distinguished from the unmeaning scrawling of an infant or a changeling. The knowledge which we conceive to be preserved in books, like the fragrance of a rose, or the gilding of the clouds, depends, for its existence, on the relation between the object and the percipient mind; and the only difference between the two cases is, that in the one, this relation is the local and temporary effect of conventional habits; in the other, it is the universal and the unchangeable work of nature. The art of printing, it is to be hoped, will in future render the former relation, as well as the latter, coëval with our species; but, in the past history of mankind, it is impossible to say how