Letter 0859

Gregory discusses advances in astronomy from Hipparchus and Pliny to Tycho Brahe and Johannes Kepler. He points out that some stars are disappearing and reappearing, as seen on star maps through time. Gregory details the Chinese method of star notation. He his hopes that members of the Royal Society observed the recent sun spots. Gregory was a mathematician and astronomer who published the first astronomy textbook to integrate Newton’s gravitational theory (Anita Guerrini, Gregory, David (16591708), Oxford Dictionary of National Biography, Oxford University Press, 2004; online edn, Jan 2008 [http://www.oxforddnb.com/view/article/11456, accessed 24 June 2013]).