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Show (continued from page 11) sun. Newton calculated that high tide should occur three hours later than it did, and attributed the difference to inertia. (It was later found to be caused by friction.) Also included is a discussion of the precession of the equinoxes, caused by the change in duection of the earth's axis. Pointing in the direction of the North Star, the axis of the earth traces a circle around it, caused by the pull of the s un and the m oon on the earth's bulging equator. T he rate is only fifty seconds of precession a year, and Newton calculated that it would require 26,000 years to make a complete circle. Newton also tackled the problem of comets, seen only briefly in the sky, and showed that they were affected by gravity, traveling around the sun in elliptical orbits. It has been suggested that the Principia ended a line of investigation in science-that of the motion of celestial bodies-because, after Newton, the matter was thought to be settled once and for all. On the other hand, he opened a new line of investigation with his work of light and colors. But theories about optics hardly began with Newton. Aristotle had some clear-cut notions about light and color, many of which were wrong. If there is anything that scientists have learned, it is that, true or not, there is no final word in science. Newton's corpuscular theory of optics fell out of fashion with the ascendancy of the wave theory, but the advent 0f quantum physics has demonstrated that light is a £unction of both wave and "corpuscle." Einstein's theory of relativity, enunciated in 1915, seemed to render N ewton's law of universal gravitation obsolete; but while on a theoretical level that may be so, 0n a practical level, Newton's Jaw is still valid. Newton's Jaw of gravity holds as long as an extremel y heavy object is not involved. In explaining why Mercury's orbit did not follow the same elliptical path, the principle of relativity was invoked. The inverse square law does hold except near inordinately heavy objects. Newton's laws of motion hold as long as speeds do not approach the speed of light. ewton knew nothing about the speed of light, but he made the first important discoveries about the nature of it. What makes Newton's approach to optics different is the magnitude of his experimentation. His interest in optics was prompted by difficulties encountered in the telescopes of his day. Light was distorted at the edge by the lenses, and focusing on one area only distorted other areas. Newton made his own telescope, a small six-inch model, using the principle of reflection which was secured by means of a m irror built into the telescope. Since reflection is defined as a condition where the angle of incidence is equal to the angle of refraction, there was no distortion of the image. And, while the problem with the lense was solved by later generations, in Newton's time the reflecting telescope was a marked improvem ent over existing instruments. The story is told of how he got hold of a glass prism, cut a small slit in his blind to let the sunlight through, and noticed that when the light passed through the prism, the rays w ere bent (refracted) in different directions, revealing the color of the " spectrum" (Newton's name). When a second prism was added, the colors remained the same. The red, for example, was passed through the second prism as red, and retained its redness when passed through blue glass and reflected off green paper. Although not all colors were displaced in the spectrum, Newton discovered seven colors, the basic colors of violet, indigo, blue, green, yellow, orange, and red. He believed that in his matter-in-motion world, red was caused by larger atoms (corpuscles), which were bent less easily by the prism; violet, on the other hand, was caused by smaller bodies, which were bent more easily. He discovered, too, that mixing the colors gave white again. Mixing some of them, gave a white-like color. Mixing red and yellow, he found, gave orange; mixing yellow and blue gave green. Newton's great discovery, then, was that the prism did not change the nature of the light given off by the sun; it simply revealed it as the source of color because color was contained in it. Like the Prin cipia, the Opticks, which was published in 1704 and went through three editions in Newton's lifetime, consisted of three books. Book I dealt with the reflection and refraction of hght, the formation of images, the production of spectra by prisms, the properties of colored light, and the composition and dispersion of white light. Book II dealt with the production of colors in interference phenomena, and Book III was a record of experiments in diffracti on and included a list of forty three " Questions," or queries, covering a whole range of subjects. When Newton began his systematic investigati on of light and colors, he revealed himself to be an experimenter of the first order. While his Principia was based on theoretical speculation, his Opticks was not. He displayed an unusual capacity as a scientist to be as much at home in experimentation as in theoretical speculation. Because the Opticks was written in English, it appealed to a much wider audience than did the Principia, which was written in Latin. The Opticks is, in fact, extremely readable-a claim that can not be m ade by many of the great books of science. But that was not enough to keep it in print fo r one hundred and fifty years, whereas The Principia was republished on a regular basis. So difficult were the m athematics on which the Principia was based that many scien tists of t he day were unable to understand it, and it had to be popularized by the few mathematicians who understood what Newton was up to. The di fficulty was exacerbated by the choice of using, for the Principia, old geometri cal concepts to express ideas mo re suited to Newton' s calculus-but this he had not shared with the scientific world, and he seemed in no hurry to do so. Benjamin Franklin was a great admirer of the Opticks, as was Jefferson, and reread it several times. But Franklin, like others not well trained in mathematics, lacked the knowledge to grasp the explanation of gravitation contained in the Pri ncipia. n some ways, Newton was as much a figure of the Renaissance as he was of the Age of Discovery; and like Galileo, who died the year that Newton was born, he owed much to the influences of the Middle Ages. One would perhaps find that easier to understand in Galileo's case than in Newton's; but while Galileo took the best that the science of the Middle Ages had to offer, Newton took the worst. And even though Newton had Robert Boyle's books on chemistry in his library, he also had books on alchemy, a favorite magical bias of the Rosicrucians, a secret brotherhood founded in the early seventeen cent ury who drew heavily from the alchemic lore of the Middle Ages. Although N ewton has been called " the last of the magicians,"and although occult interests were attractive to him all his life, he was as capable of making nature yield her secrets as any man who ever lived. But to do so he, like Galileo, had ultimately to forsake authority. Newton once said, "Plato is m y fri end, Aristotle is m y friend, but my best friend is truth .11 But Newton understood, as well as any person alive, the futility of attempting to master the truth of science. A few years before he died, he revealed his assessment of what he had accomplished: 111 do not know what may appear to the world, but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shel1 than ordinary, while the great ocean of truth lay all undiscovered before me." Elusive as it ma y be, Newton pursued truth all his life. Truth, as it turns out, has always been the best friend of science. PRESENTED BY GERALD R. SHERRATI THE SCULPTOR: Jerry Anderson, noted Utah sculptor, resides in Silver Reef (Leeds), Utah, where he also maintains his studio. He is represented on the SUU campus with the Founders' Monument an d the statue of pioneer heroine Ellen "N ellie" Pucell Unthank. Widely recognized as a m aster of bronze sculpture, his works are characterized by a ~ strong design impact with careful attention to anatomy and historical detail. His work can be found in many private and museum collections from California to Washington D .C. and his sculptures have twice won the "Best of Show" award at the AmericanCanadian Classic exhibition. He has been featured in television newscasts in Utah, Wyoming and Texas. In 1981, after 20 successful years in the structural and ornamental iron industry in Southern California, he returned to Utah to devote full time to his artwork. THE AUTHOR: Eugene T. Woolf is a Professor Emeritus of Philosophy and Literature and Director of the Grace Adams Tanner Center for Human Values at Southern Utah University. He has been under continuous contract at the university since 1953, serving in his 43 years at the institution in a number of administrative positions, including chair of the English department, Dean of the College of Arts and Letters, and Administrative Assistant to the President, and has evaluated academic programs at several Utah colleges and universities for the Utah State Office of Education and for the State Board of Regents. For several years he held the . position of Associate Commissioner for Academic Affairs in the Utah System of Higher Education. Dr. Woolf served as President of the Utah Council of Teachers of English, Chair of the Utah Endowment for the Humanities, and President of the Iron County School Board. |