# Newton's Principia

Title page of Isaac Newton's Philosophiæ naturalis principia mathematica. Imprimatur S. Pepys, Reg. Soc. præses, Julii 5. 1686. Londini: Jussu Societatis Regiæ ac typis Josephi Streater, 1687 [Rare Books Collection QA803.A2]In August 1684 Edmond Halley visited Isaac Newton (1642-1727) in Cambridge and asked him what path a planet would describe around the sun if attracted to it by a force which varied inversely as a square of the distance. Newton replied that it would follow an elliptical orbit and that he had already proved this mathematically. Unfortunately, he could not find his proof among his papers and promised to send it to Halley later.

Three months later he sent Halley a paper entitled *De motu corporum gyrum* (*On the motion of bodies in orbit*). Halley suggested publication and Newton, initially reluctant, eventually agreed. Over the next eighteen months he revised and expanded this paper into* Philosophiæ naturalis principia mathematica.* As the Royal Society had insufficient funds to publish it, it was printed at Halley’s expense in 1687.

In *Principia,* Newton, using his three laws of motion and the law of universal gravitation, accounted for the the motion of planets, moons and comets within the solar system and showed that objects here on earth and in the heavens follow the same mathematically describable natural laws. Newton further refined and revised his ideas in two later editions published in 1713 and 1726.

## In this exhibition

- A society of virtuosi
- Boyle and Hooke
- Wilkins and Locke
- Silviculture
- Newton and his champions I
- Newton's Principia
- Isaac Barrow
- Newton's Opticks
- Wallis's Opera mathematica

- Newton and his champions II
- The wider world
- Biologists at the Royal Society
- Scrutinizing the skies
- Select bibliography