## Isaac Newton

Extracts from the book

“Newton’s first years at Cambridge were interrupted when the great plague hit and so in 1665 he was forced to return to the family home at Woolsthorpe in the country and didn’t return to Cambridge until 1667. But this interlude of 2 years turned out to be his making where his major discoveries occurred – the apple falling from the tree and his theory of universal gravitation set out some years later in his masterpiece known as *The Principia* published in 1686-87. In his own words when reminiscing on these 2 years :

‘In the beginning of the year 1665 I found the Method of approximating series & the Rule for reducing any dignity of any Binomial into such a series. The same year…I had the method of fluxions & the next year in January had the Theory of colours…And the same year I began to think of gravity extending to the orb of the Moon… All this was in the two plague years of 1665 and 1666. For in those days I was in the prime of my age for invention & minded Mathematicks & Philosophy more then at any time since.’^{1}

Newton had discovered and invented much more than gravity – such as the laws of motion and the invention of calculus, the core of mathematics. Later he made discoveries in optics and even built a new telescope. After his return to Cambridge his genius at mathematics was recognized by the then (first) Lucasian Professor of Mathematics, Isaac Barrow. Newton had written De Analysi per aequationes numero terminorem infinitas (On analysis by Means of Equations with an Infinite Number of Terms)^{2} which contained the binomial theorem he had discovered in 1665^{3}. Barrow had sent this paper in July 1669 to an amateur mathematician of the day, John Collins, who published mathematical books relating to algebra and navigation.^{4} Newton had a habit of sitting on things without revealing them and had a peculiar shyness for his work. To take one example, he invented the binomial theorem which was extremely useful in expanding equations into infinite series such as in trigonometry where he could expand sine and cosine functions beautifully and of immense importance in science. He went down to London to meet Collins in November 1669 and discussed his telescope, harmonics and many mathematical things. 2 years later when Collins was to publish work relying on some insights Newton had given him, Newton wanted his contribution to remain anonymous, telling Collins he had no desire ‘to gain the esteeme of one ambitious among the croud to have my scribbles printed’.^{5} This bizarre shyness prevented Newton becoming known as the most brilliant mathematician of his age.^{6} By this time Barrow had become aware of Newton’s incredible ability and so in September 1669 he was appointed Lucasian Professor of Mathematics in 1669 – a position held more recently by Stephen Hawking.^{7}

Newton’s shyness to publish was later galvanised a year later when he presented his optics paper. Before he became a Fellow of the Royal Society in 1672,^{8} he had sent the Royal Society (only founded 10 years earlier in 1660) a telescope which he had made (and which King Charles II is said to have looked through) and said he had a far richer gift to give to the Royal Society which he termed ‘the oddest, if not the most considerable detection, which hath hitherto been made in the operations of nature.’^{9} Some weeks later he sent his optics paper to the Royal Society and in the opening passage said:

“To perform my late promise to you, I shall without further ceremony acquaint you, that in the beginning of the year 1666 (at which time I applied myself to the grinding of the Optick glasses of other figures than *Spherical*), I procured me a Triangular glass-prism, to try therewith the celebrated Phaenomena of Colours. And in order thereto having darkened my chamber, and made a small hole in my window-shuts, to let in a convenient quantity of the sun’s light, I placed my Prism at its entrance, that it might be refracted to the opposite wall. It was at first a very pleasing divertisement, to view the vivid and intense colours produced thereby; but after a while applying myself to consider them more circumspectly, I became very surprised.

*Extract from Chapter 1 ISAAC NEWTON*

^{1}Newton quote from N. Guiccardini, *Isaac Newton and Natural Philosopy*, Reaktion Books 2018, p43^{2}N. Guiccardini, *Isaac Newton and Natural Philosophy*, Reaktion Books 2018, p49^{3 }Iliffe , *Newton, A Very Short Introduction*, Oxford University Press 2007, p18^{4} N. Guiccardini op.cit., pp49-50^{5 }Iliffe , Newton, *A Very Short Introduction*, Oxford University Press 2007, p42^{6} Ibid, p43^{7} Ibid, p41^{8} N. Guiccardini op.cit., p81 refers to his election in 1672 as a ‘member’ of the Royal Society whilst Rattansi op.cit. at p41 refers to him as a ‘Fellow’ of the Royal Society^{9} Newton quote from PM Rattansi, op.cit. p41