Newton's Laws Describe The Properties Of Motion. Photo:Ihtisham Kabir

As a schoolboy I learned that an apple fell on Newton's head and led him to the discovery of gravity. While studying engineering, I tackled his science and mathematics. Recently, though, a physicist friend surprised me by claiming that Newton had been an avid alchemist. An investor friend then told me about Newton's experience with stock bubbles.
Newton's scientific discoveries are milestones of civilisation. But alchemy? That was the medieval craft of turning metals to gold. And dabbling in the stock market? To me, these activities sounded decidedly un-Newtonian.
My interest piqued, I read James Gleick's biography of Newton. Firsthand information on Newton's life (1642-1727) is sparse. Still, no evidence appears to exist for the apple story; further, Galileo had experimented with falling objects earlier and Newton knew about it. But so what? Newton's story still boggles the mind. He was the first in his family to read and write, becoming fluent in Latin and English. He worked alone, publicity-shy, often to satisfy his own curiosity and learn the truth, sometimes for days at a stretch eating and drinking very little.
Alongside his laws of motion, Newton also made profound discoveries on light and astronomy. In his quest for precise mathematical models for his science, he needed new tools. In a dazzling leap of imagination, he conceived the infinitesimal an abstract quantity so small that it is very close to, but not quite, zero. Discovery of the calculus followed (in parallel with Leibniz in Germany.) Finding no English word for some of his ideas, he coined them: mass, for example.
He worked well with his hands, too, building the first reflecting telescope. Sometimes he over-reacted, once inserting a blunt pin in between his eyeball and eye socket to see the effect of eyeball pressure on the perception of colour.
He secretly practised alchemy for decades which gave him slow mercury poisoning. His voluminous writings on alchemy remained hidden for several centuries. While today it might seem like mumbo-jumbo, Gleick says alchemy indirectly helped Newton clarify his understanding of physics. That's because he became comfortable with the idea of invisible forces and processes.
Those dealing with today's stock market unpredictability have an unlikely partner in Newton who in 1720 traded shares of the South Sea Company, one of the earliest stock bubbles. His first investment doubled. But then, he reinvested at peak prices and lost 20,000 Pounds. His words expressed his frustration: “I can calculate the motion of heavenly bodies but not the madness of people.”
Newton was not without faults. He ruthlessly attacked those who disagreed with him, particularly the scientist Robert Hooke. Reasoning that light does not turn corners like sound, he stuck to an (incorrect) particle theory of light.
Towards the end of his life, Newton was appointed Master of the Mint and supervised the re-minting of all English coins while chasing down counterfeiters. He remained a lifelong bachelor and died wealthy but without a will.

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