Sound, Light and Heat

Sound, Light and Heat

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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. 1881 edition. Excerpt: ...but when the 1. (?. aKTiv (aktin) = a ray. light has penetrated into the substance, it is, in a manner, sifted; certain of the rays are extinguished, the waves forming them are retarded, and their motion, is destroyed, while the remaining rays of the spectrum, which are not retarded and destroyed, are discharged from the substance by inward reflection, and reaching the eye, give the substance its colour. "The process by which natural bodies acquire their colours is therefore a negative one. The colours are produced by subtraction, not by addition." Where there is no light there can be no colour. The vividly coloured paper of a room is a perfect blank in the dark, and it is only when waves of light fall on it, some of which are absorbed, and others, according to the nature and texture of the paper, discharged by reflection from within its substance, that it can be properly said to have any colour. 229. A substance which absorbs all the light-waves appears black; if all the waves be absorbed equally, but not entirely, the substance appears grey, but if the absorption is unequal, the substance is coloured. If all the waves be reflected the substance appears white. 230. Hence, a rose is red because the white light of the sun which enters its substance is reflected from surfaces within, and in returning through the substance has its green extinguished. All the blue and yellow rays, or all the waves of the spectrum, excepting those producing red light, are lifted out and absorbed, or in other words destroyed, and only the red ones are reflected. Grass is green because it absorbs all the red rays, and reflects only the blue and yellow ones, which together produce green, the complementary colour, as it is called, to red. Again, there are some...
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Product details

  • Paperback | 56 pages
  • 189 x 246 x 3mm | 118g
  • United States
  • English
  • black & white illustrations
  • 1236492110
  • 9781236492111