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The following article is part of an in-depth biography of Sir Isaac Newton, the English mathematician and scientist, author of the ''Principia''. It portrays the years after Newton's birth in 1642, his education, as well as his early scientific contributions, before the writing of his main work, the Principia Mathematica in 1685. ==Birth and education== Isaac Newton was born on Christmas Day, 25 December 1642 (4 January 1643 Gregorian calendar)〔During Newton's lifetime, two calendars were in use in Europe: the Julian or 'Old Style' in Britain and parts of northern Europe (Protestant) and eastern Europe, and the Gregorian or 'New Style', in use in Roman Catholic Europe and elsewhere. At Newton's birth, Gregorian dates were ten days ahead of Julian dates: thus Newton was born on Christmas Day, 25 December 1642 by the Julian calendar, but on 4 January 1643 by the Gregorian. By the time he died, the difference between the calendars had increased to eleven days. Moreover, prior to the adoption of the Gregorian calendar in the UK in 1752, the English new year began (for legal and some other civil purposes) on 25 March ('Lady Day', i.e. the feast of the Annunciation: sometimes called 'Annunciation Style') rather than on 1 January (sometimes called 'Circumcision Style'). Unless otherwise noted, the remainder of the dates in this article follow the Julian Calendar.〕 at Woolsthorpe Manor in Woolsthorpe-by-Colsterworth, a hamlet in the county of Lincolnshire. At the time of Newton's birth, England had not adopted the Gregorian calendar and therefore his date of birth was recorded as Christmas Day, according to the Julian calendar. Newton was born three months after the death of his father, a prosperous farmer also named Isaac Newton. Isaac Newton, Sr. was described as a "wild and extravagant man." Born prematurely, young Isaac was a small child; his mother Hannah Ayscough reportedly said that he could have fitted inside a quart mug. When Newton was three, his mother remarried and went to live with her new husband, the Reverend Barnabus Smith, leaving her son in the care of his maternal grandmother, Margery Ayscough. The young Isaac disliked his stepfather and held some enmity towards his mother for marrying him, as revealed by this entry in a list of sins committed up to the age of 19: "Threatening my father and mother Smith to burn them and the house over them."〔Cohen, I.B. (1970). Dictionary of Scientific Biography, Vol. 11, p.43. New York: Charles Scribner's Sons〕 Later on his mother returned after her husband died. From the ages of 12 through 17, he was educated at The King's School, Grantham (where his signature can still be seen upon a library window sill). He was removed from school, and by October 1659, he was to be found at Woolsthorpe-by-Colsterworth, where his mother, widowed by now for a second time, attempted to make a farmer of him. He hated farming.〔Westfall 1994, pp. 16–19〕 Henry Stokes, master at the King's School, persuaded his mother to send him back to school so that he might complete his education. This he did at the age of eighteen, achieving an admirable final report. In June 1661, he was admitted to Trinity College, Cambridge as a sizar—a sort of work-study role.〔Michael White, ''Isaac Newton'' (1999) (page 46 )〕 At that time, the college's teachings were based on those of Aristotle, whom Newton supplemented with modern philosophers such as Descartes and astronomers such as Copernicus, Galileo, and Kepler. In 1665, he discovered the generalised binomial theorem and began to develop a mathematical theory that later became infinitesimal calculus. Soon after Newton had obtained his degree in August 1665, the University closed down as a precaution against the Great Plague. Although he had been undistinguished as a Cambridge student,〔ed. Michael Hoskins (1997). Cambridge Illustrated History of Astronomy, p. 159. Cambridge University Press〕 Newton's private studies at his home in Woolsthorpe over the subsequent two years saw the development of his theories on calculus, optics and the law of gravitation. In 1667 he returned to Cambridge as a fellow of Trinity. Newton had stated that when he had purchased a book on astrology at Stourbridge fair, near Cambridge, he was unable, on account of his ignorance of trigonometry, to understand a figure of the heavens which was drawn in the book. He therefore bought an English edition of Euclid's ''Elements'' which included an index of propositions, and, having turned to two or three which he thought might be helpful, found them so obvious that he dismissed it "as a trifling book", and applied himself to the study of René Descartes' ''Geometry''. It is reported that in his examination for a scholarship at Trinity, to which he was elected on 28 April 1664, he was examined in Euclid by Dr. Isaac Barrow, who was disappointed in Newton's lack of knowledge on the subject. Newton was convinced to read the ''Elements'' again with care, and formed a more favourable estimate of Euclid's merit. The study of Descartes's ''Geometry'' seems to have inspired Newton with a love of the subject, and introduced him to higher mathematics. In a small commonplace book, dated January 1664, there are several articles on angular sections, and the squaring of curves and "crooked lines that may be squared", several calculations about musical notes, geometrical propositions from François Viète and Fran's van Schooten, annotations out of John Wallis's ''Arithmetic of Infinities'', together with observations on refraction, on the grinding of "spherical optic glasses", on the errors of lenses and the method of rectifying them, and on the extraction of all kinds of roots, particularly those "in affected powers." In this same book the following entry made by Newton himself, many years afterwards, gives a further account of the nature of his work during the period when he was an undergraduate: That Newton must have begun early to make careful observations of natural phenomena is shown by the following remarks about halos, which appear in his ''Optics'', book ii. part iv. obs. 13: He formulated the three laws of motion: 1st Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. 2nd The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma. Acceleration and force are vectors (as indicated by their symbols being displayed in slant bold font); in this law the direction of the force vector is the same as the direction of the acceleration vector. 3rd For every action there is an equal and opposite reaction. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Early life of Isaac Newton」の詳細全文を読む スポンサード リンク
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