The following article is part of a biography of Sir Isaac Newton, the English mathematician and scientist, author of the Principia. It portrays the years after Newton's birth in 1643, his education, as well as his early scientific contributions, before the writing of his main work, the Principia Mathematica, in 1685.
Overview of Newton's life Sir Isaac Newton is known for many scientific findings. These discoveries include the laws of motion, the theory of gravity, and basic calculus. Although Newton was predominantly known for his discoveries in mathematics and physics, he also put much effort and study into chemistry, biblical history, and optics. One of Newton's most famous writings was the Principia where he described some of his major findings of time, physics, mathematics, and calculus. Although his theories soon became universal, he faced much opposition to his early theories. Specifically, his theory of gravity faced criticism from leading scientists such as Christiaan Huygens and Leibniz. After a few years of debate, Newton's concept of gravity became universally accepted as he became the dominant figure in the European continent.
Birth and education Isaac Newton was born 25 December 1642 Old Style (4 January 1643 on the Gregorian calendar, which is now used)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's 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, before 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 25 December, according to the Julian calendar.)
Newton was born three months after the death of his father, a prosperous farmer also named Isaac Newton. His father was described as a "wealthy and uneducated man". Born prematurely, young Isaac was a small child; his mother Hannah Ayscough reportedly said that he could have fit inside a quart mug. When Newton was three, his mother remarried and went to live with her new husband, the Reverend Barnabas 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 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 age 12 to age 16, Newton resided with William Clarke, apothecary, in Grantham, where he acquired his interest in chemistry. While living with the Clarke family, Newton was educated at the free grammar school (where his signature can still be seen upon a library window sill). He spent much of his time on independent pursuits, and did poorly in school. Newton was also captivated with mechanical devices and drawing. Not only did he analyze drawings and machines, he actually constructed them himself. From windmills to clocks, Newton constructed models of many objects that surrounded him in his everyday life. 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, which he hated. Henry Stokes, master at the King's School, persuaded his mother to send him back to school so that he might complete his education. Newton's uncle also had an influence in persuading his mother to send him back to school as he could see the natural ability of Isaac. This he did at the age of eighteen, achieving an admirable final report.
Newton lived his childhood during some of the most turbulent times in England as the Civil War began in 1642. Although the effects of the country's issues may not have directly affected Newton, the school and universities in England were certainly impacted. Whether it was for the better or worse was to be determined, but Newton was certainly going to have a unique schooling due to the country's unbalance.
Manuscript evidence shows that Newton's earliest known piece writing, a Latin phrasebook, as well as the first letter in his hand which has yet been found, addressed to a ‘Loving friend’, were copied from an unpublished version of a work on Latin pedagogy by William Walker, a schoolmaster and rector whose acquaintance with Newton is documented from 1665. This suggests an early influence of the schoolmaster on the natural philosopher when he was still a schoolboy.
In June 1661, he was admitted to Trinity College, Cambridge as a sizar—a sort of work-study role. 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 of London. Although he had been undistinguished as a Cambridge student,Hoskins, Michael (ed.) (1997). Cambridge Illustrated History of Astronomy. Cambridge University Press. p. 159. Newton's private studies at his home in Woolsthorpe over the next 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 Isaac Barrow, who was disappointed in Newton's lack of knowledge of the subject. Newton was convinced to read the Elements again with care, and formed a more favourable opinion of Euclid's merit.
Newton's study of Descartes' Geometry seems to have inspired him 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 Frans 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 afterward, 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:
Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it. 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 sometimes 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. For every action there is an equal and opposite reaction.
Academic career In January 1665 Newton took the degree of Bachelor of Arts. The persons appointed (in conjunction with the proctors, John Slade of Catharine Hall, Cambridge, and Benjamin Pulleyn of Trinity College, Newton's tutor) to examine the questionists were John Eachard of Catharine Hall and Thomas Gipps of Trinity University. It is a curious accident that we have no information about the respective merits of the candidates for a degree in this year since the "ordo senioritis" of the Bachelors of Arts for the year is omitted in the "Grace Book".
It is supposed that it was in 1665 that the method of fluxións (his term for calculus of variations) first occurred to Newton's mind. There are several papers in Newton's handwriting bearing dates 1665 and 1666 in which the method is described, in some of which dotted or dashed letters are used to represent fluxions (i.e. derivatives), and in some of which the method is explained without the use of dotted letters.
Both in 1665 and 1666 Trinity College was dismissed on account of the Great Plague of London. On each occasion it was agreed, as shown by entries in the "Conclusion Book" of the college, dated 7 August 1665, and 22 June 1666, and signed by the master of the college, Dr Pearson, that all fellows and scholars who were dismissed on account of the pestilence be allowed one month's commons.
Newton must have left college before August 1665, as his name does not appear in the list of those who received extra commons on that occasion, and he tells us himself in the extract from his commonplace book already quoted that he was "forced from Cambridge by the plague" in the summer of that year. He was elected a fellow of his college on 5 October 1667. There were nine vacancies, one caused by the death of Abraham Cowley the previous summer, and the nine successful candidates were all of the same academic standings. A few weeks after his election to a fellowship Newton went to Lincolnshire and did not return to Cambridge until the following February. In March 1668, he took his M.A. degree.