Desaguliers, Hogs’ bladders, and St Paul’s cathedral

John Theophilus Desaguliers FRS (1683 – 1744) was elected to the Royal Society in 1714, with responsibility for experiments, Hooke having died in 1703. The second edition of Newton’s The Principia was published in 1713, and the third in 1726.  The experiments overseen by Desaguliers, carried out in April and July 1719, consisted, principally, inContinue reading “Desaguliers, Hogs’ bladders, and St Paul’s cathedral”

Gottfried Kirch, his wife Maria, and their calendars

Although he did not travel, Newton sat at the centre of an intellectual community that stretched from India to America, though its members were all European, and Newton noted their nationality, provided that they were English. Gottfried Kirch (1639-1710), the son of a cobbler or tailor who came to Germany as a penniless refugee fromContinue reading “Gottfried Kirch, his wife Maria, and their calendars”

Newton, a priest of nature

Newton was an intensely learned and determined theologian, whose striking views are of universal interest. He was a priest of nature in that, for him, understanding the universe, as he Newton understood it, was closely related to understanding God. In this, my eighth blog, I pay homage to Rob Iliffe’s great book Priest of Nature:Continue reading “Newton, a priest of nature”

Newton and the orbit of comets part 2

In this blog I plan to outline the method that Newton, and then Halley, used to compute the orbits of comets. It is a challenge to those who are handy with a computer, or who have the skills of draughtsmanship; and I hope that it will also be of interest to people who are interestedContinue reading “Newton and the orbit of comets part 2”

Newton and the orbit of comets

Isaac Newton, like many astronomers before and since, was inspired by comets. His theory of gravitation enabled him to compute the orbit of comets as detailed in The Principia. The mathematical formula that Newton developed to calculate the orbit of comets enabled him, and Halley, who was Flamsteed’s successor as Astronomer Royal, to determine ifContinue reading “Newton and the orbit of comets”

Some simple arithmetic…

This blog is dedicated to the memory of the singular John Machin, professor of astronomy at Gresham College. He calculated 𝜋 to 100 places of decimals, and, in The Principia, Newton quotes in full an article by Machin on the motion of the nodes of the moon. Cajouri, in his revision of Motte’s translation ofContinue reading “Some simple arithmetic…”

Calculus in Newton’s Principia

I would like to start my fourth blog by drawing your attention to Melvyn Bragg’s BBC Radio 4 In Our Time broadcast on Émilie du Châtelet (see image above) the brilliant translator of Newton’s The Principia into French and lover of Voltaire. Alas, she died of childbirth complications before her translation was published (it cameContinue reading “Calculus in Newton’s Principia”

Newton’s inverse square law

One of the most famous results in The Principia is the theorem that states that if a body is acted on solely by a force that attracts to a fixed point, and obeys the inverse square law, its orbit is a conic. And that, conversely, if a body that is acted on solely by aContinue reading “Newton’s inverse square law”

Translating Newton’s Principia

Before turning to consider the fundamental insights that gave rise to The Principia, I want to touch on the question of how we approach a treatise on Mathematical Physics that was written over 200 years ago. This is a matter that concerns the reader as well as the translator. Some translators seek to transport theContinue reading “Translating Newton’s Principia”

Did an apple really fall on Newton’s head?

Everyone knows that The Principia was based on the inspiration that struck Newton when the apple struck his head, as you can see from the cartoon above. The thought that passed through his head was as follows: “Clearly the earth attracts the apple in the same way that it attracts the moon, and the forceContinue reading “Did an apple really fall on Newton’s head?”