Isaac Newton has long been a hero of mine, but this summer he acquired toes of clay when I learned that the famous story of how the falling apple inspired his theory of gravitation is probably not true.

While researching my new television series on what the Tudors and Stuarts did for science (and for us), I found that Sir Isaac first told this story to antiquarian William Stukeley on 15 April 1726 --- that is 60 years after the fruit supposedly fell and inspired the mathematics that united the motions in the heavens with those on Earth.

Stukeley records the event vividly: ''I visited Sir Isaac Newton, at his lodgings in . Kensington . & spent the whole day with him, & alone. After dinner, being a fine day, we sat in the garden, under the apple trees, and drank tea there. He told me among other discourse it was in such a situation, that he first took the notion of the gravitation of matter: from an apple dropping off a tree. Why shd this apple, always and invariably fall to the earth, in a perpendicular line; why shd it not fall upwards, sideways, or obliquely?.''

Such questions, said Stukeley, ''revolved in his mind'' and ''thence he began to consider, & discover, the mode, . & laws of this universal power in matter. & apply them to the motion of the heavenly bodys, to the cohesion of matter; & to unfold the true philosophy of the universe.''

This, we have been led to believe, happened in Newton's ''annus mirabilis'' of 1665/6, when Cambridge had been shut down because of the plague and Newton had gone home to Woolsthorpe, south of Grantham in Lincolnshire. In that year he invented calculus (his 'method of fluxions'), solved other major mathematical problems, and sorted out the colours of the rainbow. But did he really see an apple fall and begin to scribble the basic equations of gravitation on the back of an envelope - or rather one of his mum's leasehold contracts?

In an elegant piece of research, Nick Kollerstrom of University College London has shown that Newton almost certainly did not begin to think about universal gravity until 1682, when the sight of Halley's comet reawakened his interest in heavenly bodies.

Until then his letters clearly show that he believed the planets are swept  around the Sun in a great vortex, like soap flakes going down a plug hole, as described by Descartes. But Halley's comet upset that idea because it moved in a retrograde orbit - that is in the opposite direction to all the
planets - which meant it could not possibly be driven by a great vortex. 

Christopher Wren, Robert Hooke, and Edmond Halley, coffee-house friends, could not quite manage to work out the detailed mathematics of the planetary orbits. Newton had boasted that he understood it all; so Halley visited him in Cambridge and asked for the details. Newton said he would send him a paper in due course, and then started working on the problem. In 1687, Newton unveiled his masterwork - Philosophiae Naturalis Principia Mathematica - arguably the most important book in science. 

Why did Newton invent the apple story? His arch-rival Robert Hooke had written about gravity in 1674, and was close to solving the mathematical problems involved. Newton could never admit that Hooke had beaten him to anything, and so it looks as though he made up the apple story in order to
prove that he had sorted out the basics of gravity in 1666, well before Hooke. Then, as now, being first in science was everything. 

This may be unkind; Newton may really have been inspired by seeing an apple fall, but the evidence is against him. This was just one of the fascinating revelations of my background research for What the Tudors and Stuarts did for us which appeared on BBC2 in the Autumn of 2002.

I already knew that Henry VIII had divorced Catherine of Aragon in order to marry Anne Boleyn, and so cut himself off from the Roman Catholic Church.  However, I did not realise that when he married Anne in January 1533 she was already pregnant. Nor did I realise that as a direct result of antagonising the Catholics, Henry became so worried about invasion by the French or the Spanish, that he told his metal-workers to focus on making cannons, because he could not afford to import sufficient numbers of expensive bronze guns from Flanders. As a result, in 1543 they managed to produce the world' s first cast-iron cannon in the weald of Kent. By the end of the century England was exporting cast-iron cannons. Thus, Henry VIII started the British arms trade.

After Henry's divorce, furthermore, the Vatican cut off the supplies of the chemical alum, which meant we could not dye our cloth. Alum is a mordant that binds the dye to the fibres of the cloth; without such a mordant the colours are less vivid and soon wash out.

We have no naturally-occurring alum in England, and it took until about 1600 to work out how to make it. The method is hard to believe: they hacked grey shale from the cliffs on the coast of north Yorkshire, roasted it slowly for nine months on a bonfire, washed the residue, and added either
toasted seaweed or stale human urine. 

Then they concentrated the liquor in big lead pans until a fresh chicken's egg just floated to the surface, at which point they left the liquor to cool for four days, and out came beautiful colourless crystals of pure alum. Chemistry was not officially invented for another 150 years, but this extraordinary blend of alchemy and trial-and-error became the first chemical industry in the country, and over the next 250 years thousands of tons of alum were made in north Yorkshire - all as a direct consequence of Henry's rift with Rome.

Among the other highlights of this tempestuous period were the printing of the Bible in English, the invention of submarines, pencils, theatres, real tennis, telescopes, microscopes, the Magdeburg Hemispheres, and Boyle's law - or Mr Towneley's hypothesis, referring to the weather watcher who was the first to spot an inverse relationship between volume and pressure of a fixed mass of air.

Huygens, Papin, Savery, and finally Thomas Newcomen showed how these novel scientific ideas about pressure and temperature could be turned to technological benefit and, with the first useful steam engines, ushered in the industrial revolution. Meanwhile, Wren, Hooke, Halley, and Newton were the giants who introduced modern science.

Newton was no angel but he certainly knew about the importance of spin and managed to charm the in people of his day, including the poet Alexander Pope, who wrote for his epitaph:

Nature, and Nature's laws lay hid in night:
God said, let Newton be! and all was light.

Daily Telegraph, 11 September 2002

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