The Montgomery advertiser., 1903-09-30
WHY THE SKY IS BLUE.
Scientists Learn That the Atmosphere
 Is Much Deeper Than Has Been Supposed.

Been supposed.
 Brooklyn Eagle.
 sky. It has grown familiar to all by daily observation from childhood, yet few persons realize the great scientific and artistic interest attaching to this beau- tiful color. Sir Isaac Newton tried to explain the color in the ear 1875 by referring 1t to the blue colors seen in the soap bubbles used in his experiments. He thought the air was filled with small particles of water which reflect the blue portions of the suns light falling upon our earth and thus produce the blue tints of the firma- ment
 Sir John Herschei explained the color of the sky by Newton's theory, but later writers have proved that In some im- portant respects his theory was wrong.
 In 1869 Professor John Tyndall the fa- nous British physicist found that he could produce sky blue" by experiments in the laboratory. For this purpose he filled glass tube about a yard long and three inches in diameter with air of one-tenth the ordinary density mixed with nitrfte of butyl vapor. which Is extreme ly volatile. Then. on passing through the mixture a powerful beam of electric light in a room otherwise dark the mix ture precipitated beautiful blue cloud which in color rivaled the finest Italian sky. Further experiments proved to Tyn- dall that he had at last discovered the secret of the blue color of the sky which had puzzled the greatest philosophers of all ages.
 Lord Rayleigh, the famous professor of experimental physics at Cambridge. Eng land. and one of King Edwards original twelve members of the new Order of Mer- 1t. has investigated Tyndall's theory of the color of the sky by profound mathe- matical researches extending over many years. He confirms Tyndalrs theory that the blue arises from the reflection of sum- light from small particles in the air less than one one-hundred thousandth of an inch in diameter.
 These atomic particles All the atmos- phere, and by reflecting the blue part of the Suns light, give the dome of the heavens a bluish tint.
 Some of these particles are water but most of them are composed of the oxy- gen and nitrogen of the air.
 Professor T. ]. J. See Of the United States Navy Is one of the American sci- entists who has studied the subject In another aspect. He has observed the color of the sky in various attitudes in high mountains and in dry and moist countries such as Egypt and Greece, and Arizona and the Mississippi Valley. His conclusion Is that the beautiful red col ors of sunsets and sunrises So much spoken of by Greek and Roman writers and so often Illustrated in landscape painting. arises from water vapor in the lower regions of the atmosphere, absorb ing the blue and transmitting the red light. According to pr. See the reddish colors come from that part of our air within five miles of the earth's surface while the deep blue of the sky arises from reflections of minute particles in the higher parts of our atmosphere.
 The water vapor does not extend very high, clouds never rising higher than ten miles above the earth. The blue streaks cast by clouds at sunset show that the red arises from the earth. while the blue has it's seat very high up. Above the atmos- phere the sky has all the biackness of the darkest night.
 Professor See has watched the duration of the blue sky after dark, and found it to continue for about an hour and fifteen minutes and from this he shows that the atmosphere extends to a height of fully ls0 miles. Astronomers have usually found the height of the atmosphere by computing the height of meteors. but none ever made the height of the atmos- phere over 100 miles.
 The study of the blue color of the sky thus proves also that our atmosphere ex- tends considerably higher than scientists have heretofore supposed.
 On dark days the blue color of the sky is shut out by clouds and combinations of colors due to reflecting clouds and countless myriads of particles in the ethereal regions high above the earth give the bright light which is so much relished in daily life. The nature of the blue sky So much admired by all man kind since the days of Homer and Job. | now fully explained by modern science | still preserves its ancient beauty. and | will inspire mans mind through coming |