That in my answer to his first letter I refused his correspondence, told him I had laid philosophy aside, sent him, only the experiment of projectiles (rather shortly hinted than carefully described), in compliment to sweeten my answer, expected to hear no further from him could scarce persuade myself to answer his second letter did not answer his third, was upon other things thought no further of philosophical matters than, his letters put me upon it, and therefore may be allowed not to have had my thoughts of that kind about me so well at that time. 'That it is not candid to require me now to confess myself, in print, then ignorant of the duplicate proportion in the heavens for no other reason but because he had told it me in the case of projectiles, and so upon mistaken grounds, accused me of that ignorance. That what he told me of the duplicate proportion was erroneous, namely, that it reached down from hence to the centre of the earth.

I intended in this letter to let you understand the case fully but it being a frivolous business, I shall content myself to give you, the heads of it in short, viz, that I never extended the duplicate proportion lower than to the superficies of the earth, and before a certain demonstration I found the last year, have suspected it did not reach accurately enough down so low and therefore in the doctrine of projectiles never used it nor considered the motions of the heavens and consequently Mr Hooke could not from my letters, which were about projectiles and the regions descending hence to the centre, conclude me ignorant of the theory of the heavens. Wren knew the duplicate proportion when I gave him a visit and then Mr Hooke (by his book Cometa written afterwards) will prove the last of us three that knew it.

I am almost confident by circumstances, that Sir Chr. 'Sir, In order to let you know the case between Mr Hooke and me, I give you an account of what passed between us in our letters, so far as I could remember for 'tis long since they were writ, and I do not know that I have seen them since. In a letter, Newton responded to Halley as follows: Halley acknowledged that although Hooke should be credited for the theory, 'the demonstration of the curves generated thereby belonged wholly to Newton'. English astronomer and mathematician Edmond Halley attempted to mediate and get Newton to agree that Hooke deserved some credit for the invention of 'the rule for the decrease of gravity being reciprocally as the squares of the distances from the centre'. Natural philosopher Robert Hooke, Anthony Lucas, mathematical professor at Liege Francis Line,Ī physician in Liége, and many others. The publication of Newton's discoveries led to controversies involving English Many of the letters are lost, but it is clear that Flamsteed was helpful, especially regarding Kepler's definition of Saturn. Newton's own copy of his Principia, with hand written corrections for the second edition.īetween 16, Newton had a very extensive correspondence with John Flamsteed, who was then the astronomer-royal.

Principia mathematica