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CHARLES HUT TON THE GEORDIE WHO WEIGHED T H E E A RT H BY JOHN SMITH (STAFF 04 TO PRESENT) RGS DIRECTOR OF PARTNERSHIPS AND FORMER HEAD OF MATHS As former RGS parent, (The Viscount) Matt Ridley writes in his recent book, How Innovation Works, “…innovation is nearly always a gradual, not a sudden thing. Eureka moments are rare, possibly non-existent”
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idley investigates this thesis in realms as diverse as Computing, Healthcare and Food, but it is in the context of Scientific innovation that his well-argued book resonated with me. In the history of Physics and my own subject of Mathematics, breakthroughs are almost always an iterative, collaborative process: a succession of great minds each standing on the proverbial shoulders of giants. It can take a veritable human pyramid of such giants to crack even the simplest of questions. Think: ‘Why is the sky blue?’, ‘How did the Universe begin?’ or, more pertinent to this article, ‘How much does the Earth weigh?’. It is the last of these questions that troubled the former coal-miner, school teacher and criminally forgotten Geordie genius, Charles Hutton. In the book, Gunpowder and Geometry: The Life of Charles Hutton, Pit Boy, Mathematician and Scientific Rebel, author Benjamin Wardhaugh takes us on a breath-taking journey from the coal-pits of Newcastle to the highest echelons of the British scientific establishment, taking in tutoring of Royal Grammar School students on the way. We learn of a man of innate intellectual curiosity: dare I say, someone who embodied a real Love of Learning and a true Ambition to Succeed. Building on the work of Sir Isaac Newton, who had established the link between motion and mass in the late 1600s (the Universal Law of Gravitation), it was not until 100 years later that Hutton set about designing the experiments that would help to weigh the earth. Needless to say, he couldn’t place the earth on the bathroom scales. So, how was this feat to be achieved? Well, first of all, he needed to find an object big enough to displace a hanging plumb-line through its gravitational pull. In 1774, he was in luck: the Reverend Nevil Maskelyne, Astronomer Royal, had found an unusually symmetrical and largeenough mountain in the Scottish Highlands: Schiehallion. Maskelyne was able to measure the angle of deflection of the plumbline in the vicinity of the gravitational pull of the mountain, providing a key clue on which Hutton could build his work. Four years later, Hutton used these measurements to calculate the density of the Earth, which he figured to be 4.5 times that of water, and surprisingly higher than the density of rock. The scientists were edging closer to the mass of the Earth, but it took Henry Cavendish another 20 years to finish the line of enquiry at his mansion in London.
