|
Isaac Newton was born on 4 January 1643 in the manor house in
Woolsthorpe, three months after his father's death. He was so tiny that no one expected him to survive. When Newton was three
years old, his mother remarried, an event which improved her situation, and led to three more children, but which deprived
Isaac of a mother. His stepfather, the Reverend Mr Smith, would not take the three-year-old Newton along with his mother,
and he was left at Woolsthorpe with his grandparents.
We know little about Newton's pre-teen years, other than that he attended day schools in the neighbouring
villages of Skillington and Stoke. In August 1653, when Newton was 10, the Reverend Smith died and Isaac's mother returned
to Woolsthorpe. At the age of 12, Newton was sent to grammar school in Grantham. Here he got the standard education of the
time, which included Latin and Greek, and some Bible studies - taught at the time to reinforce the Protestant faith in England.
He was placed in the bottom class at Grantham, but a playground fight that he won due to sheer spirit began a rise to the
top of the school.
He mostly kept his own company, as he was a 'sober, silent, thinking lad', and when he did associate
with others, it was nearly always with girls. He is remembered from that time in Grantham for 'his strange inventions and
extraordinary inclination for mechanical works'. Among these were a windmill powered by a treadmill run by a mouse - the latter
urged on by tugs on a string tied to its tail - dolls' furniture for the girls at Newton's school, and a little four-wheeled
vehicle for himself, which ran by crank, which he could turn while sitting in it.
When he turned 17, Newton's mother called him home to Woolsthorpe, and appointed a trusty servant to
teach him about real life - running the farm. Newton did not take well to this. Set to watch the sheep, he would instead build
model waterwheels, and other gadgets, and the sheep would often escape. His uncle and his school master watched all this from
a distance, and strongly recommended that Newton's mother send him back to school to prepare for university. She conceded
when the school master agreed to drop the fee for school attendance.
Newton set out for Cambridge early in June 1661, matriculating to Trinity College. He entered Trinity
as a subsizar, a poor student who earned his keep by performing menial tasks for the fellows, fellow commoners (very rich
students), and pensioners (the merely affluent). It seems that his mother was not prepared to pay for any more of his education.
At Cambridge he was exposed to many philosophical texts and ideas, especially those of the French philosopher René Descartes,
who was very highly regarded at the time. After studying the work of Descartes Newton was attracted to mechanical philosophy,
and began to question the environment around him, including the nature of matter, cosmic order, light, colours and sensations.
To test a question about colours, he stared at the sun with one eye until all the colours changed.
As a result he had to shut himself up in the dark for several days before he could rid himself of the spots now floating before
his eyes.
He had found a new passion. In order to pursue these mathematical studies, Newton needed to secure
a permanent position at Cambridge. He had not distinguished himself during his three years, and failed to secure a fellowship.
His only chance was to be elected to a scholarship in 1664. It seems that his genius was recognised, and he was sent to be
assessed by the only person at Cambridge who could judge his competence in the unorthodox studies he had chosen to pursue.
Dr Isaac Barrow examined him and Newton was made a scholar of the house, a position guaranteed for at least four years. Newton
surrendered himself to his mathematics, forgetting to eat, and sometimes forgetting to sleep.
He was not solely interested in mathematics, but embraced the whole of natural philosophy, which he
explored from a range of viewpoints, ranging all the way from mathematics to alchemy. Within natural philosophy he gave new
direction to optics, mechanics, and celestial dynamics. His studies in mathematics were perhaps the most important, as the
discipline the subject imposed on his imagination marked the difference between wild tacks of fancy and fruitful discovery.
In the summer of 1665, a plague epidemic descended on many parts of England. The sickness hit Cambridge,
and the university closed down on 10 October, although many of the students had already left long before that. The plague
was to stay in Cambridge for two years, and the university only opened again in the spring of 1667. Newton decided to return
to Woolsthorpe while the university was closed. It was thus in his home village, in 1666 during this enforced hiatus in his
studies, that he had his annus mirabilis. This is at least partly legend, as he was in fact working on many of his
ideas during 1664 and 1665, but 1666 was indeed a fruitful year for Newton.
Working on mathematics, Newton applied himself to drawing tangents beneath curves (differentiation)
and finding areas under curves (integration). He took these 'new analyses' and expanded upon them, computing logarithms to
calculate the area under a hyperbola, and eventually finding a method by which to find the area under virtually every algebraic
curve then known to mathematicians.
Newton began to treat the areas under curves kinetically, as areas swept out by a moving line. From
the idea of motion he derived the term 'fluxional', to describe this method, something we now call calculus. Newton produced
three papers on calculus in 1666, the resulting body of work leaving other mathematicians in awe of his ability. In one act,
Newton had become the leading mathematician in Europe. Before then nobody knew who Isaac Newton was, and had no idea that
the work of this young man of 24 had left the acknowledged masters for dead.
Newton then moved to the science of mechanics. Descartes' conception of motion had analysed impact
in terms of the force of the moving body impinging on others. Newton treated the moving body as the passive subject of external
forces acting upon it, and this new approach to impact dynamics remains the basis for the analysis of impact today.
The question of the mechanics of circular motion was more complex, and Newton agreed with Descartes
that a body in circular motion strives to constantly recede from the centre. This seemed to add weight to the idea that bodies
in motion had their own force. Newton took his studies on impact a step further, and used them to show that the earth's rotation
does not fling bodies into the air because the force of gravity, measured by the rate of falling bodies, is greater than the
centrifugal force arising from the rotation.
At Woolsthorpe, Newton read a book by Galileo called Dialogue Concerning the Two Chief World Systems
and this work set him thinking. Newton knew all about Johannes Kepler's work on how planets circle the sun and, in the book,
Galileo was talking about how things fell to the earth.
Newton wondered if he couldn't think of a way to join up the two ideas. Could the same force that kept
the moon from being thrown away from the earth apply to gravity at the earth's surface? Newton made the link, and called his
findings the Law of Universal Gravitation. While his connection between the two was famously 'occasioned by the fall of an
apple' from a tree in the orchard at Woolsthorpe, the idea did not come to Newton in a flash of inspiration, but was developed
over time.
Newton then started experimenting with the 'celebrated phenomenon of colours'. The view held at the
time was that colour was a mixture of light and darkness. Hooke was a proponent of this theory of colour, and had a scale
that went from brilliant red, which was pure white light with the least amount of darkness added, to dull blue, the last step
before black, which was the complete extinction of light by darkness. Newton realised that this was not the case - a white
page with black writing did not appear coloured when viewed from a distance and the black and white blended, it appeared as
grey.
People were using prisms to experiment with colour, and thought that somehow the prism coloured the
light. Newton obtained a prism, and set up his so that a spot of sunlight fell onto it. In their experiments, Descartes, Robert
Hooke and Edward Boyle had put a screen close to the other side of the prism and seen that the spot of light came out as a
mixture of colour. Newton realised that to get a proper spectrum you needed to move the screen a lot further away.
In the study upstairs at Woolsthorpe, he used the 22 feet from the window to the far wall to project
a beautiful spectrum. The white light split into different colours and each colour had been bent a different amount by the
prism. But to prove that the prism was not colouring the light, Newton did an Experimentum Crucis - his crucial experiment.
He put a screen in the way of his spectrum, and this screen had a slit cut in it, and only let the green light go through.
Then he put a second prism in the green light. If it was the prism that was colouring the light, the
green should come out a different colour. The pure green light remained green, unaffected by the prism. Newton had proved
that white light was made up of colours mixed together, and the prism merely separated them - he was the first person to understand
the rainbow.
While his two-year hiatus at Woolsthorpe was a time of intense concentration on his work, his results
were not of divine revelation, but rather the culmination of years of thought. 'I keep the subject constantly before me',
he said, 'and wait 'till the first dawnings open slowly, by little and little, into a full and clear light.'
Back at Cambridge, Newton faced another election. This time it was for a fellowship, which would cement
his place in the scientific establishment, and give him the freedom to continue the studies he had begun. In October 1667,
Newton was elected a fellow of the College of the Holy and Undivided Trinity. From then he lived in Trinity for 28 years.
While he did not get the academic fellowship he expected at Cambridge during this time, it was partly his own fault as he
isolated himself from other fellows, not speaking to anyone at dinner time, and not joining colleagues on the bowling green.
In October 1669, Newton became the second ever Lucasian professor of mathematics - essentially appointed
by Barrow when he stood down. For the first year of his tenure, he devoted much of his time to continuing his optics research.
After this, encouraged by Barrow and John Collins, he focused again on mathematics. Collins tried in vain to push Newton forward
into the scientific community, but Newton preferred anonymity and eventually he pulled away even from Collins.
It was Newton's reflecting telescope, made in 1668, that finally brought him into full view of the
scientific community. His work with colours led him to believe that refracting telescopes, which were subject to colour interference,
were outdated. He made his reflecting telescope entirely on his own, some parts of it with tools that he made specifically
for the purpose. His invention made telescopes much smaller - his was only six inches long, and one inch in diameter, yet
it magnified over 30 times.
It was especially useful when looking at distant bodies such as Jupiter, which only reflected small
amounts of light, and to this day, the most powerful telescopes continue to use reflecting dishes according to Newton's principle.
Newton was so proud of his telescope, that he couldn't resist showing it off. Word went around Cambridge, and then the Royal
Society got wind of the invention, and asked to see it. When the telescope arrived, it caused a sensation. Newton was ecstatic,
despite his pretence of indifference, and in return sent them his theory of colours in a letter.
The letter Newton sent contained nothing new, but it was the first time that his work had been made
available for discussion by other scientists. Robert Hooke, a leading power at the Royal Society, however, considered optics
to be his domain, and he refuted much of what Newton said. This critique of Newton's work was to be the beginning of a long
and spiteful rivalry between the two men, with Newton taking an arrogant stance, and Hooke often accusing Newton of plagiarism.
Newton also received some criticism of his optics experiments from some Jesuits, who claimed that they could not replicate
Newton's prism experiment, and therefore it was wrong. Newton erupted in anger at this, and at Hooke. He convinced himself
of a conspiracy against him, and gave up the study of optics, refusing to correspond with anyone about it.
Newton moved to chemistry, and more specifically alchemy. He laboured day and night in his chemical
laboratory and immersed himself in mathematical and mystical calculations. In the late 1670s theological studies occupied
most of his time. He began a history of the church, starting in the fourth and fifth centuries. In 1686 he presented his single
greatest work, the Philosophiae Naturalis Principia Mathematica ('Mathematical Principles of Natural Philosophy').
In it, Newton revealed his laws of motion, and the law of universal gravitation. The Royal Society were going to publish Newton's
book, but withdrew due to lack of funds. The astronomer Edmund Halley, who was wealthy and thought highly of Newton, eventually
paid for its publication. The Principia redirected Newton's intellectual life, away from theology and alchemy and
back into 'real' science.
After the Principia appeared, Newton became somewhat bored with Cambridge. In 1689, he was
elected a Member of Parliament for the University, and he moved to London. While he only lasted a year as an MP, not seeking
re-election in 1690, he very much enjoyed his time in London. He began to see people socially, notably Christiaan Huygens.
In 1696 Newton was appointed Warden of the London Mint, becoming Master in 1699. He took these duties very seriously, revising
the British coinage and taking severe measures against forgers.
He was elected President of the Royal Society in 1703, but only just - very few members seemed to want
this cantankerous genius as their president. However, he held this office until his death - perhaps because the members were
too afraid to vote him out. Less than two years after his election, Queen Anne knighted Newton in Cambridge. His presidency
led Newton to resume relations with Astronomer Royal, John Flamsteed. For more than ten years, Newton interfered with Flamsteed's
affairs, exercising his authority as president.
He also fortified his position, appointing supporters in positions of authority within the Society
- Halley succeeded a secretary, and another Newton supporter, Brook Taylor, was made the other secretary.
In 1709, Newton began work on a second edition of Principia, and he also published a second
edition of Opticks, however after he moved to London, he did nothing but reshuffle ideas that he had had in Cambridge.
As he became older, he seemed concerned with leaving his image behind - he had many portraits painted. As his health
began to deteriorate he began to distribute his wealth amongst his family. After a series of debilitating illnesses he died
on 31 March 1727. |
