This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1868 Excerpt: ...hold in its arms." 150. The Sensibility of the Retina is easily exhausted.--When we look at a bright light, and then turn the eye towards a moderately lighted surface, a dark spot is seen; showing that the part of the.retina on which the bright light fell has lost for the moment its sensibility, or become blind. If the ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1868 Excerpt: ...hold in its arms." 150. The Sensibility of the Retina is easily exhausted.--When we look at a bright light, and then turn the eye towards a moderately lighted surface, a dark spot is seen; showing that the part of the.retina on which the bright light fell has lost for the moment its sensibility, or become blind. If the bright object be of one color, the part of the retina on which its image falls becomes insensible to rays of that color, but not to those of other colors. This explains the appearance of what are called complementary colors. For example, if a red wafer be stuck upon a sheet of white paper, and viewed steadily for some time with one eye, and then the eye be turned to another part of the paper, a greenish spot will appear of the size and shape of the wafer. The red image has made the retina blind to red light, but it has left it sensitive to the remaining colors which make up white light; and when red is taken from white light the combination of the other colors gives a greenish hue. If the wafer had been green, the spot seen would have been red. 151. Color-Blindness.--In some persons the retina appears to be affected in one and the same way by different colors, or even by all colors. The most common form of this color-blindness, as it is called, is an inability to distinguish red and green. Thus many persons cannot distinguish between the colors of the leaves of the cherry-tree and its fruit. In some cases, persons who were thus colorblind without being aware of it, and who have been employed on railways, have mistaken the color of signal lights, and serious accidents have been the result. This blindness may arise either from a defect in the retina, or from some peculiarity in the absorptive powers of the humors of the eye. 152. Single Vi...
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Add this copy of Natural Philosophy: For High Schools And Academies to cart. $60.09, new condition, Sold by Booksplease rated 4.0 out of 5 stars, ships from Southport, MERSEYSIDE, UNITED KINGDOM, published 2015 by Arkose Press.
Add this copy of Natural Philosophy: for High Schools and Academies to cart. $84.20, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2015 by Arkose Press.
Add this copy of Natural Philosophy, for High Schools and Academies to cart. $86.11, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2010 by Kessinger Publishing.
