1 . Biography
Isaac Newton was born at Woolthorpe, Lincolnshire, England on Christmas Day 1642. On that cold winter night, the sick, premature baby seemed unlikely to live. Gradually, however, he gained strength to survive. But Isaacs first few years were a struggle. His mother had become a widow two months before Isaac was born. Even with the help of her own mother, she had difficulty caring for Isaac in addition to running their farm while the Civil War in England raged around them.Several years later, his mother married the minister from nearby North Witham, but Isaac remained at Woolthorpe with his grandmother. As he grew, however, he visited his mother frequently. He eagerly read books from his stepfathers well stocked library, in addition to reading the Bible regularly.
Isaac attended school at Kings College in nearby Grantham. Rather than playing outdoor games as a boy, he preferred to make models of such things as windmills and carts. Not only were these in exactly the right proportions, but all of the moving parts actually worked.Isaacs mother was widowed for the second time when he was 14 years old. Isaac was taken out of school to run the family farm to support his mother and her three younger children. However, Isaac missed his studies greatly and his mother recognized this. When Kings College offered to waive tuition fees because of his ability and poor circumstances, Isaac returned and completed his schooling. Teachers and other students were impressed with the boys knowledge of the Bible.
2 . Introduction
Newton, Sir Isaac (1642 1727), mathematician and physicist, one of the foremost scientific intellects of all time. Born at Woolsthorpe, near Grantham in Lincolnshire, where he attended school, he entered Cambridge University in 1661, he was elected a Fellow of Trinity College in 1667, and Lucasian Professor of Mathematics in 1669. He remained at the university, lecturing in most years, until 1696. Of these Cambridge years, in which Newton was at the height of his creative power, he singled out 1665 1666 (spent largely in Lincolnshire because of plague in Cambridge) as the prime of my age for invention. During two to three years of intense mental effort he prepared Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) commonly known as the Principia, although this was not published until 1687.As a firm opponent of the attempt by King James II to make the universities into Catholic institutions, Newton was elected Member of Parliament for the University of Cambridge to the Convention Parliament of 1689, and sat again in 1701 1702. Meanwhile, in 1696 he had moved to London as Warden of the Royal Mint. He became Master of the Mint in 1699, an office he retained to his death. He was elected a Fellow of the Royal Society of London in 1671, and in 1703 he became President, being annually re elected for the rest of his life. His major work, Opticks, appeared the next year, he was knighted in Cambridge in 1705.
As Newtonian science became increasingly accepted on the Continent, and especially after a general peace was restored in 1714, following the War of the Spanish Succession, Newton became the most highly esteemed natural philosopher in Europe. His last decades were passed in revising his major works, polishing his studies of ancient history, and defending himself against critics, as well as carrying out his official duties. Newton was modest, diffident, and a man of simple tastes. He was angered by criticism or opposition, and harboured resentment, he was harsh towards enemies but generous to friends. In government, and at the Royal Society, he proved an able administrator. He never married and lived modestly, but was buried with great pomp in Westminster Abbey.Newton has been regarded for almost 300 years as the founding examplar of modern physical science, his achievements in experimental investigation being as innovative as those in mathematical research. With equal, if not greater, energy and originality he also plunged into chemistry, the early history of Western civilization, and theology, among his special studies was an investigation of the form and dimensions, as described in the Bible, of Solomons Temple in Jerusalem.
3 . Optics
In 1664, while still a student, Newton read recent work on optics and light by the English physicists Robert Boyle and Robert Hooke, he also studied both the mathematics and the physics of the French philosopher and scientist Ren? Descartes. He investigated the refraction of light by a glass prism, developing over a few years a series of increasingly elaborate, refined, and exact experiments, Newton discovered measurable, mathematical patterns in the phenomenon of colour. He found white light to be a mixture of infinitely varied coloured rays (manifest in the rainbow and the spectrum), each ray definable by the angle through which it is refracted on entering or leaving a given transparent medium. He correlated this notion with his study of the interference colours of thin films (for example, of oil on water, or soap bubbles), using a simple technique of extreme acuity to measure the thickness of such films. He held that light consisted of streams of minute particles. From his experiments he could infer the magnitudes of the transparent corpuscles forming the surfaces of bodies, which, according to their dimensions, so interacted with white light as to reflect, selectively, the different observed colours of those surfaces.
The roots of these unconventional ideas were with Newton by about 1668, when first expressed (tersely and partially) in public in 1672 and 1675, they provoked hostile criticism, mainly because colours were thought to be modified forms of homogeneous white light. Doubts, and Newtons rejoinders, were printed in the learned journals. Notably, the scepticism of Christiaan Huygens and the failure of the French physicist Edm? Mariotte to duplicate Newtons refraction experiments in 1681 set scientists on the Continent against him for a generation. The publication of Opticks, largely written by 1692, was delayed by Newton until the critics were dead. The book was still imperfect. the colours of diffraction defeated Newton. Nevertheless, Opticks established itself, from about 1715, as a model of the interweaving of theory with quantitative experimentation.
4 . Mathematics
In mathematics too, early brilliance appeared in Newtons student notes. He may have learnt geometry at school, though he always spoke of himself as self taught, certainly he advanced through studying the writings of his compatriots William Oughtred and John Wallis, and of Descartes and the Dutch school. Newton made contributions to all branches of mathematics then studied, but is especially famous for his solutions to the contemporary problems in analytical geometry of drawing tangents to curves (differentiation) and defining areas bounded by curves (integration). Not only did Newton discover that these problems were inverse to each other, but he discovered general methods of resolving problems of curvature, embraced in his method of fluxions and inverse method of fluxions, respectively equivalent to Leibnizs later differential and integral calculus. Newton used the term fluxion (from Latin meaning flow) because he imagined a quantity flowing from one magnitude to another. Fluxions were expressed algebraically, as Leibnizs differentials were, but Newton made extensive use also (especially in the Principia) of analogous geometrical arguments. Late in life, Newton expressed regret for the algebraic style of recent mathematical progress, preferring the geometrical method of the Classical Greeks, which he regarded as clearer and more rigorous.
Newtons work on pure mathematics was virtually hidden from all but his correspondents until 1704, when he published, with Opticks, a tract on the quadrature of curves (integration) and another on the classification of the cubic curves. His Cambridge lectures, delivered from about 1673 to 1683, were published in 1707.
5 . The calculus priority dispute
Newton had the essence of the methods of fluxions by 1666. The first to become known, privately, to other mathematicians, in 1668, was his method of integration by infinite series. In Paris in 1675 Gottfried Wilhelm Leibniz independently evolved the first ideas of his differential calculus, outlined to Newton in 1677. Newton had already described some of his mathematical discoveries to Leibniz, not including his method of fluxions. In 1684 Leibniz published his first paper on calculus, a small group of mathematicians took up his ideas.
In the 1690s Newtons friends proclaimed the priority of Newtons methods of fluxions. Supporters of Leibniz asserted that he had communicated the differential method to Newton, although Leibniz had claimed no such thing. Newtonians then asserted, rightly, that Leibniz had seen papers of Newtons during a London visit in 1676, in reality, Leibniz had taken no notice of material on fluxions. A violent dispute sprang up, part public, part private, extended by Leibniz to attacks on Newtons theory of gravitation and his ideas about God and creation, it was not ended even by Leibnizs death in 1716. The dispute delayed the reception of Newtonian science on the Continent, and dissuaded British mathematicians from sharing the researches of Continental colleagues for a century.
6 . Mechanics and gravitation
According to the well known story, it was on seeing an apple fall in his orchard at some time during 1665 or 1666 that Newton conceived that the same force governed the motion of the Moon and the apple. He calculated the force needed to hold the Moon in its orbit, as compared with the force pulling an object to the ground. He also calculated the centripetal force needed to hold a stone in a sling, and the relation between the length of a pendulum and the time of its swing. These early explorations were not soon exploited by Newton, though he studied astronomy and the problems of planetary motion.Correspondence with Hooke (1679 1680) redirected Newton to the problem of the path of a body subjected to a centrally directed force that varies as the inverse square of the distance, he determined it to be an ellipse, so informing Edmond Halley in August 1684. Halleys interest led Newton to demonstrate the relationship afresh, to compose a brief tract on mechanics, and finally to write the Principia.
Book I of the Principia states the foundations of the science of mechanics, developing upon them the mathematics of orbital motion round centres of force. Newton identified gravitation as the fundamental force controlling the motions of the celestial bodies. He never found its cause. To contemporaries who found the idea of attractions across empty space unintelligible, he conceded that they might prove to be caused by the impacts of unseen particles.Book II inaugurates the theory of fluids. Newton solves problems of fluids in movement and of motion through fluids. From the density of air he calculated the speed of sound waves.Book III shows the law of gravitation at work in the universe. Newton demonstrates it from the revolutions of the six known planets, including the Earth, and their satellites. However, he could never quite perfect the difficult theory of the Moons motion. Comets were shown to obey the same law, in later editions, Newton added conjectures on the possibility of their return. He calculated the relative masses of heavenly bodies from their gravitational forces, and the oblateness of Earth and Jupiter, already observed. He explained tidal ebb and flow and the precession of the equinoxes from the forces exerted by the Sun and Moon. All this was done by exact computation.
Newtons work in mechanics was accepted at once in Britain, and universally after half a century. Since then it has been ranked among humanitys greatest achievements in abstract thought. It was extended and perfected by others, notably Pierre Simon de Laplace, without changing its basis and it survived into the late 19th century before it began to show signs of failing. See Quantum Theory, Relativity.
7 . Alchemy and chemistry
Newton left a mass of manuscripts on the subjects of alchemy and chemistry, then closely related topics. Most of these were extracts from books, bibliographies, dictionaries, and so on, but a few are original. He began intensive experimentation in 1669, continuing till he left Cambridge, seeking to unravel the meaning that he hoped was hidden in alchemical obscurity and mysticism. He sought understanding of the nature and structure of all matter, formed from the solid, massy, hard, impenetrable, movable particles that he believed God had created. Most importantly in the Queries appended to Opticks and in the essay On the Nature of Acids (1710), Newton published an incomplete theory of chemical force, concealing his exploration of the alchemists, which became known a century after his death.
8 . Historical and chronological studies
Newton owned more books on humanistic learning than on mathematics and science, all his life he studied them deeply. His unpublished classical scholia
9 . Religious convictions and personality
Newton also wrote on Judaeo Christian prophecy, whose decipherment was essential, he thought, to the understanding of God. His book on the subject, which was reprinted well into the Victorian Age, represented lifelong study. Its message was that Christianity went astray in the 4th century AD, when the first Council of Nicaea propounded erroneous doctrines of the nature of Christ. The full extent of Newtons unorthodoxy was recognized only in the present century. but although a critic of accepted Trinitarian dogmas and the Council of Nicaea, he possessed a deep religious sense, venerated the Bible and accepted its account of creation. In late editions of his scientific works he expressed a strong sense of Gods providential role in nature.
10 . Publications
Newton published an edition of Geographia generalis by the German geographer Varenius in 1672. His own letters on optics appeared in print from 1672 to 1676. Then he published nothing until the Principia (published in Latin in 1687, revised in 1713 and 1726, and translated into English in 1729). This was followed by Opticks in 1704, a revised edition in Latin appeared in 1706. Posthumously published writings include The Chronology of Ancient Kingdoms Amended (1728), The System of the World (1728), the first draft of Book III of the Principia, and Observations upon the Prophecies of Daniel and the Apocalypse of St John (1733).