Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: THE SPACE-SENSATIONS OF THE EYE. /TVHE tree with its hard, rough, grey trunk, its num- J- berless branches swayed by the wind, its smooth soft, shining leaves, appears to us at first a single, indivisible whole. In like manner, we regard the sweet, round, yellow fruit, the warm, bright fire, with its manifold moving tongues, as a single thing. One name designates the whole, one word draws forth from the depths of oblivion all associated memories, as if they were strung upon a single thread. The reflexion of the tree, the fruit, or the fire in a mirror is visible, but not tangible. When we turn our glance away or close our eyes, we can touch the tree, taste the fruit, feel the fire, but we cannot see them. Thus the apparently indivisible thing is separated into parts, which are not only connected with one another but are also joined to other conditions. The visible is separable from the tangible, from that which may be tasted, etc. The visible also appears at first sight to be a singlething. But we may see a round, yellow fruit together with a yellow, star-shaped blossom. A second fruit is just as round as the first, but is green or red. Two things may be alike in color but unlike in form ; they may be different in color but like in form. Thus sensations of sight are separable into color-sensations and space-sensations. Color-sensation, into the details of which we shall not enter here, is essentially a sensation of favorable or unfavorable chemical conditions of life. In the process of adaptation to these conditions, color-sensation may have been developed and modified.1 Light in- ICompare Grant Allen, The Color-Sense .(London: Trubner