Fragments Of Science (volume 1); A Series Of Detached Essays, Addresses, And Reviews

Paperback | February 1, 2012

byJohn Tyndall

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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. 1892. Excerpt: ... II. RADIATION.1 1. Visible and Invisible Radiation. BETWEEN the mind of man and the outer world are interposed the nerves of the human body, which translate, or enable the mind to translate, the impressions of that world into facts of consciousness and thought. Different nerves are suited to the perception of different impressions. We do not see with the ear, nor hear with the eye, nor are we rendered sensible of sound by the nerves of the tongue. Out of the general assemblage of physical actions, each nerve, or group of nerves, selects and responds to those for the perception of which it is specially organised. The optic nerve passes from the brain to the back of the eyeball and there spreads out, to form the retina, a web of nerve filaments, on which the images of external objects are projected by the optical portion of the eye. This nerve is limited to the apprehension of the phenomena of radiation, and, notwithstanding its marvellous sensibility to certain impressions of this class, it is singularly obtuse to other impressions. 1 The Rede Lecture delivered in the Senate House before the University of Cambridge, May 16, 18G5. Nor does the optic nerve embrace the entire range even of radiation. Some rays, when they reach it, are incompetent to evoke its power, while others never reach it at all, being absorbed by the humours of the eye. To all rays which, whether they reach the retina or not, fail to excite vision, we give the name of invisible or obscure rays. All non-luminous bodies emit such rays. There is no body in nature absolutely cold, and every body not absolutely cold emits rays of heat. But to render radiant heat fit to affect the optic nerve a certain temperature is necessary. A cool poker thrust into a fire remains dark for a time, but when...

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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. 1892. Excerpt: ... II. RADIATION.1 1. Visible and Invisible Radiation. BETWEEN the mind of man and the outer world are interposed the nerves of t...

Format:PaperbackDimensions:128 pages, 9.69 × 7.44 × 0.27 inPublished:February 1, 2012Publisher:General Books LLCLanguage:English

The following ISBNs are associated with this title:

ISBN - 10:0217835961

ISBN - 13:9780217835961

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