Makers of Science, III: Newton

The Makers of Science By Dr. F. S. Harris, Director Utah Agricultural Experiment Station

III —Newton In science, as in other branches of learning, advancement was long retarded by the ignorance and superstition that reigned supreme during the dark ages. Every manifestation of nature was associated with magic; every discovery was attributed to witchcraft rather than to intelligent research. Those who ad- vanced ideas in any way conflicting with the dogmas of the time were persecuted and often burned at the stake for heresy. With the discovery of the new world and a breaking of the chains of priestcraft that had bound all advancement for cen- turies, a revival of learning was ushered in. This manifested itself in literature, art, and science. While the present-day free- dom in thought was unknown during the renaissance, there was a great advance over the days when the inquisition silenced all who ventured ever so little from the narrow path of strict ortho- doxy. A century of greater freedom had enabled students of nature to discover many facts regarding the universe and had so changed the attitude of the masses toward science that a- new discovery was not considered necessarily evil. It was about this time, on Christmas day, 1642, that a sickly infant was born to widow Newton in the hamlet of Woolsthorpe, Lincoln county, England. Contrary to the expectation of all, the child lived and became robust. He was named Isaac after his father, who died at the age of thirty-six several months be- fore young Isaac was born. The child's parents were humble people who tilled land that had been in the family for several hundred years. Little is known of them except that they were honest and industrious country folk. The mother married again while Isaac was still a lad and he lived with his grandmother, Mrs. Ayscough, on the family farm. Here he seems to have spent more time making kites and waterwheels than tending crops. Later he attended the village school, and with the aid of his uncle prepared for college. He matriculated at Cambridge, July 8, 1661. Due to his great aptitude for mathematics and natural philosophy, he was elected to a scholarship, April 28, 1664. Before his graduation in Jan- uary, 1665, he had begun his study of gravitation and had de-

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veloped several mathematical principles that helped in his study of the movement of heavenly bodies. Prior to this time a great deal of mystery had enveloped everything pertaining to the stars. The ancient peoples had various ideas regarding the movement of heavenly lights. The sun was supposed to represent the daily journey of one of the gods across the heavens in his fiery chariot and the earth was thought to be the center of the solar system. Anyone who doubted this explanation of things was at once set down as a heretic and was subjected to persecution. Just a century before the birth of Newton, Copernicus, a Polish monk, after thirty-six years of study, substituted the idea that the sun, and not the earth, was the center of the solar system. This gave a basis for more intelligent investigations of the movement of heavenly bodies, but this study was attended by a great deal of persecution. For teaching the plurality of worlds and other heterodox doctrine, and for refusing to recant, Bruno, after six years of imprisonment in Rome, was burned at the stake in 1600. A natural death in the dungeons of the In- quisition saved Antonio de Dominis, the explainer of the rain- bow, from the same fate; but his body and books were publicly burned in Rome in 1624. Galileo, through his invention of the telescope was able more definitely to substantiate the Copernican theory, but he was constantly subjected to the persecutions of the Inquisition and was forced to deny his findings. About this time Galileo dis- covered the laws of motion which Newton later stated. The laws are: Law 1. If no force acts on a body in motion, it continues to move uniformly in a straight line. Law 2. If force acts on a body, it produces a change in motion proportional to the force and in the same direction. Law 3. When one body exerts force on another, that other reacts with equal force upon the one. Before these laws were discovered it was thought that an external force was necessary to keep the planets moving; but now that an explanation of their motion was given, the puzzling question was what held them in their orbits. Why, for ex- ample, did the moon move around the earth instead of flying off through space in a straight line? It was not the movement of the planets that now gave trouble, but the fact that they traveled in a curved path. Kepler had established the laws of planetary orbits but Newton worked out the explanation of these laws. Through his discovery of differential calculus Newton was aide to calculate the paths taken by heavenly bodies of a given size in their orbits around other bodies. He proved that the

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attraction of the sun on planets varied inversely as the square of the distance. He tried to explain the movement of the moon in its orbit through the law of falling bodies which was known. He made his calculation and compared it with the observed orbit, but the results did not agree. The discrepancy resulted from the fact that he had used sixty in place of sixty-nine miles as a degree on the earth's surface. Not until sixteen years after the true value of a degree had been determined did he learn that his method of calculation was correct. Although he began his study of gravitation as early as 1665 when he was but twenty-three years old, it was not till 1685 that he completely elaborated the universal law of gravitation. The first book of the Principia was presented to the Royal Society, April 28, 1686. It is often said that the greatest feat accom- plished by human mind is that of Newton in arriving at the explanation of the solar system from the falling of an apple. From this it might be implied that all of this came as one bril- liant flash of imagination. As a matter of fact, Newton had been wrestling with the problem for years and had kept his great intellect constantly at work on it. He had even to develop mathematics further than it had previously been developed in order to make adequate proofs. Unlike many of the early workers in science he received recognition during his lifetime for the services he rendered. At the age of twenty-seven he was elected Lucasian professor at Cambridge, and at thirty he was made a Fellow of the Royal Society of which he was president during the last twenty-four years of his life. In 1689 he sat in Parliament for the University of Cambridge, and in 1699 he was given charge of the govern- ment mint where he worked many reforms in coinage. In 1705 he was knighted by Queen Anne. He numbered among his associates many prominent men of whom John Locke and Halley are notable examples. He died at the ripe age of 85 and was buried in Westminster Abbey. To some, his genius seemed almost divine. "Does Mr. New- ton eat, drink, sleep, like other men?" asked the Marquis de Hospital, a noted French mathematician; "I picture him to myself as a celestial genius, entirely removed from the restric- tions of ordinary matter." After his work it seemed to many that nothing remained to be discovered. This idea was ex- pressed by Pope in the following lines

"Nature and nature's laws lay hid in night, God said, Let Newton be, and all was light." This feeling was only natural after the comprehensive sys- tem of ordered knowledge of the universe that had been devel-