It was around this time that Leibniz visited London. Leibniz had been working independently on the calculus, being more concerned with the geometry of the situation, rather than any ideas of velocity or motion. In the autumn of 1675, Leibniz introduced the familiar integral sign and the d-notation for differentiation – both of these are still used today.

Newton produced the Principia Mathematica in 1687 but it nearly didn’t appear. Hooke complained that a result of his was not credited, and Newton refused to do so. The main part of the Principia consists of three books.

Book I explains Kepler’s laws of planetary motion. Newton proved Kepler’s law, that the planets orbit in ellipses – and also obtained the converse result, that if a planet under a central law of gravitation travels in an elliptical orbit, then the law of gravity must be an inverse-square one.

Book II is concerned with the movement of objects in resisting media – such as a ball bearing in treacle. Here Newton demolished a rival theory of the universe from Descartes, that all the planets move around the heavens in mini-vortices, or whirlpools.

In Book III, Newton obtains a number of amazing results – these include the calculation of the speed that a projectile needs to travel in order to escape from the Earth’s atmosphere; results on the precession of the equinoxes; the motion of comets; and the shape of the Earth as it rotates.

Newton’s Principia made him famous – few people read it, and even fewer understood it, but everyone knew that it was a great work, rather like Einstein’s Theory of Relativity over two hundred years later.

By 1696 Newton felt the need to move to London, and in that year he was appointed Warden of the Royal Mint, living in the Tower of London.

In 1703 the ailing Robert Hooke died, and with him out of the way, Newton felt happy to become involved again with the Royal Society, which had almost become defunct. It was a good time for Newton. In 1704 with no Hooke to disagree with him, he published his second-greatest book, the Opticks. The next year he was knighted by Queen Anne.

In the 1720s Newton became increasingly ill with gout and other ailments, and he died in March 1727 at the age of 84. He lay in state in Westminster Abbey amidst great pomp and ceremony, for a week preceding his funeral. At the ceremony, his pall was borne by two dukes, three earls and the Lord Chancellor. No previous scientist had ever been so honoured.

  < previous   Page 2 of 2

Comments