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Show Moon's Lifting Power Is Light Everything on Which Luna Shines Directly Down Loses Weight Washington. The great steamship Leviathan v-eiphs some ten or twelve pounds less when the moon Is directly over it than when It is near the horizon. hori-zon. Similarly B!l! Smith and his automobile, auto-mobile, little Willie Smith's teddy hear and Mrs. Smith's dainty pearl earrings all lose weight under the potent influence influ-ence of Luna. So says a bulletin from the Wash Ington (D. C.) headquarters of the National Na-tional Geographic society dealing with the moon's tide-raising force. "As a matter of fact." continues the bulletin, "everything on which the moon shines directly down loses a certain cer-tain amount of its weight But there need be iio fear that we will go float Ing moonward: the downward pull of gravity, which keeps objects on the earth's surface. Is H1.ikki.ikhi times as great as the 'liftfng power' of the moon. In other words, the greitesl effect of the moon on a given object Is to steal away one-ten-millionth of its welg.... "In the case of large bodies, like the Leviathan, this frnct on of the total weight Is appreciable. Bui even the heaviest limousine would lose only the tiniest fraction of an uince be tween six and seven one-thousandths This would be equivalent to removing only three or four drops of gasoline from the fuel tank. "Pluck a sint'le tiher from the fuzz;, coat of Willie Smith's teddy bear ano you would probably equal the moon's effect in reducing Its weight. And carefully wiping the Imperceptible dust from Mrs. Smith's earrings would no doubt, quite outdo the lunar In flucnce on them. Moonshine and the Tides. "But In spite of the smn'I effect of th3 moon's attraction on everydav ohjeds. its total result on the earth Is very marked. Its most notable ef feet 's to create the titles of the ocean -which in turn affect the world s sea borne commerce. Its fisheries, the sanitation of Its harbors, nnd even man's sen bathing activities In years to come thU moon-force may be bin nessed to create power; nlready plans are under way for the construction of tidal power stations. "How does the moon decrease weight ? "In the same way that the earth creates it. The law of gravitation formulated by Newton states that every body In existence in the universe attracts every other body. Any two bodies are drawn together, however, with a greater or less force, depend Ing on whether they are big (more accurately, have a 'great mass') or whether they are little (have a 'small mass') ; and also depending on whether wheth-er they are close together or far apart. Weight in Terms of Gravity. "When you, an adult, say that you weigh lfW) pounds, yon really mean that your 'mass' Is attracted by the huge earth, when you are on Its surface, sur-face, with the same force with which It attracts l."0 lead or brass or Iron units. which we arbitrarily call 'pounds.' Because a baby has much less mass than you. It Is drawn toward to-ward the center of the earth with a smaller force, and we say thai It weighs 8 or 10 or 13 pounds1 "But the moon attracts youi mass In exactly the same way that the earth does. It is, however. 2-'". x N ( miles away .r! times us far away as the center of the earth nnd it has only one-eightieth as much mass is the earth. So Its attraction for you Is less than that of the earth. Its pull on you Is tremendously less than migh' apjK'ar at first consideration, because any' gravitational p til I Is reduced in proportion to the square of Its dls tance. It figures out that the moon's pull at the earth's surface Is only one ten-millionth that of the earth. When the moon exerts Its greatest lifting force on you. therefore, when It floats directly overhead. It only succeeds In reducing your weight by nn amount less than lifth of a drop of water.' |