that plague was a relatively common occurrence. Their only likely knowledge of the virulence of such diseases would have come from their grandparents and great-grandparents recounting horror stories of the last major outbreak, forty years earlier, in 1625.
The plague began in London and spread to other parts of the country rapidly during the hot summer of 1665. It was always at its worst in the east of the city, in the districts of Stepney, Shoreditch, Whitechapel and around the crowded streets clustered at the foot of St Paul’s. At its height it claimed 10,000 lives a week, and in one day in September 1665 alone, 7,000 victims died. The disease was in fact bubonic plague – a bacterial infection carried by a flea which infested the black rat (Rattus rattus). Wherever rats could breed, the disease spread like wildfire. The flea carried the initial infection to humans via a bite. There was no cure and only a slim chance of survival for those unfortunate enough to become infected. Without the benefit of antibiotics, the only means of containing the disease was quarantine.
By the end of the first summer of the Great Plague, after tens of thousands had lost their lives, the quarantine laws which would eventually help to halt the spread of the disease were finally enacted and major towns and cities became citadels where travellers and visitors were entirely unwelcome. It is clear from a number of reports of the spread of the disease that it took some time for the authorities to realise they were facing a major catastrophe, and by the time they did the plague had a grip on London and had been carried to many other parts of the country. Samuel Pepys, the great monitor of the Zeitgeist, first mentioned the plague in his diary entry of 30 April 1665, noting ‘Great fears of the sickness here in the City, it being said that two or three houses are already shut up.’5 But it was not until 15 June that he reported, ‘The town grows very sickly, and the people to be afeared of it – there dying this week of the plague 112, from 43 the week before.’6
Cambridge escaped relatively lightly, and the university fared amazingly well. The first mention of the disease appears in the Annals of Cambridge of August 1665, when, we are told, the plague had prevailed and taken the life of one of the town bailiffs, a William Jennings. Things grew worse as the summer progressed, and the Stourbridge fair was cancelled that year (and in 1666) because of the fear of attracting travellers to Cambridge – especially those from the capital. According to the Annals, only 413 people died in all the parishes of Cambridge during 1665, and many of these deaths were from natural causes. They then go on to report that during a two-week period in November of that year a total of fifteen deaths from plague were recorded.7 In the colleges, there was not one case of the disease all year, largely because the majority of students, fellows and staff had left during the early summer, and those few who did stay kept any contact with the townsfolk to an absolute minimum, locking themselves away in their sanctuaries like medieval monks.
The exact date when Newton left Cambridge is unclear. He was certainly there on 23 May, because he paid his tutor Pulleyn £5.8 He was not in college for most of July and early August (the college was dismissed on 8 August), because he did not claim six and a half weeks worth of commons (food allowance) paid to those who had stayed on to risk plague during the summer. According to most accounts, he left Trinity around the end of June or the beginning of July and did not return, except for a brief spell in early 1666, for almost two years.
He travelled to his mother’s home, the manor in Woolsthorpe, where tradition has it that he made his great discoveries concerning gravity and the mathematical breakthroughs that later made him famous. It is in Woolsthorpe, in the orchard next to the house, that the famous apple is supposed to have dislodged itself with impeccable timing and set in motion the development of the theory of gravity. Thereafter, one might assume, the Principia was a mere formalising of the great revealed truth. Yet the reality, magnificent though it was in its intellectual depth and its effect upon the course of science, was far more prosaic. The truth is not so much grounded in singular fluke events or any deeply symbolic psychological drives associated with Newton living in the home of his childhood than it is to do with a gradual revelation brought about by concentration and sheer dedication. As Newton himself said when asked how he came upon his great discoveries, ‘I keep the subject constantly before me, till the first dawnings open slowly, by little and little, into the full and clear light.’9
The apple story is almost certainly a fabrication, or at the very least a highly embroidered version of the truth. Indeed, the very notion, so integral to many early accounts of Newton’s life, that there were two special years in his life during which everything was solved – the so-called anni mirabiles of 1665 and 1666 – is an extreme simplification of the facts. Although Newton’s achievements during the time he spent in Woolsthorpe sprang from intuition and inspiration and did lead to the great laws that lie as a foundation beneath our technology, they did not appear fully formed and complete. Although the years 1665 and 1666 were truly great ones for Newton’s intellectual development, they mark merely the start of his quest. If we are to label Newton’s achievements by the calendar, then the true anni mirabiles cover more than two decades, from his arrival in Woolsthorpe to the delivery of the Principia in 1687, and encapsulate his period of almost single-minded dedication to the practice of alchemy during the 1670s and ’80s as well as the gradual transmutation of his intuitive insights into hard science.
Quite how and indeed from where the initial moment of inspiration came remains a mystery, and, despite the anecdotes and varied accounts describing Newton’s efforts during 1665 and 1666, we may never know how one of the most important sets of scientific and mathematical discoveries in history was initiated.
The story of the apple has come down to us from a number of sources. First there is William Stukeley. During the spring of 1726, a year before Newton’s death, the biographer visited the great scientist in his final home in Kensington. As they walked out into the garden of the house, Newton remarked that it had been on just such an occasion that he had first realised the theory of gravity. Intrigued, Stukeley pursued the matter ‘under the shade of some appletrees, only he and myself,’ Stukeley recounts. ‘Amidst other discourse, he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. It was occasioned by the fall of an apple, as he sat in the contemplative mood.’10
Another account comes from Newton’s great admirer Voltaire, who made the English scientist famous in France with his Éléments de la philosophie de Newton (1736), in the English edition of which he says:
One day in the year 1666, Newton, having returned to the country and seeing the fruits of a tree fall, fell, according to what his niece, Mrs Conduitt, has told me, into a deep meditation about the cause that thus attracts bodies in the line which, if produced, would pass nearly through the centre of the Earth.11
As the passage relates, Voltaire received this story second-hand from Newton’s half-niece Catherine Barton, wife of John Conduitt. Voltaire never met Newton.
There is one other contemporary account of note: that of Henry Pemberton, who was the editor of the third edition of the Principia, published in 1726. He describes the scene in a similar way: ‘The first thoughts, which give rise to his Principia, he had, when he returned from Cambridge in 1666 on account of the plague. As he sat alone in the garden, he fell into a speculation on the power of gravity.’12
The common factor in all these versions of the story is that they derive directly from Newton himself and we therefore have only his word that the story is true. Perhaps, one day during
