Edmund Halley, who was the other candidate for the professorship of astronomy, had from a scientific point of view stronger claims to the appointment. To him the world is indebted for the publication of Newton’s _Principia_, which Halley undertook at his own expense, seeing that the Royal Society made difficulties about the money, and that Newton himself was too poor, and possibly too much engrossed in his study, to take the burden of it on his own shoulders. But Halley was an infidel, and this disqualified him in the eyes of the patrons of the chair. Sir Henry Savile had left his professorships open to candidates of any Christian Nation ‘if they were of good report and correct demeanour, eminently skilled in mathematics, possessed of at least a moderate knowledge of the Greek language, and if they had attained the age of twenty-six years.’ He had left the election in the hands of the Archbishop of Canterbury, the Lord Chancellor, the Chancellor of the University, the Bishop of London, the Principal Secretary of State, the two Chief Justices, the Chief Baron of the Exchequer and the Dean of Arches. With an electorate composed of such men, Edmund Halley, holding the views which he acknowledged at that time, had no chance of election. Whiston in his _Memoir_ says that ‘Bishop Stillingfleet was desired to recommend him at court, but hearing that he was a sceptick, and a banterer of religion, he scrupled to be concerned, till his chaplain Mr Bentley should talk with him about it, which he did. But Mr Halley was so sincere in his infidelity, that he would not so much as pretend to believe the Christian religion, though he thereby was likely to lose a professorship.’ David Gregorie then (or Gregory, as he now began to call himself), with the support of Sir Isaac Newton, and because of Halley’s religious views, was appointed professor. He had entered at Balliol, was incorporated A.M. on the 6th of February 1692, took the degree of M.D., and was subsequently admitted to the chair. In the previous year he had been made a Fellow of the Royal Society, and it was not long before he began to contribute to their volumes. He sent in a beautiful solution of the Florentine problem, which Viviani had sent as a challenge to British Mathematicians. His work was masterly, and delighted geometers, and in Oxford he found time to write much more than he had in Scotland, where teaching had always had to come first. He next wrote a defence of his uncle against the Abbé Gallois, who accused him of plagiarising from Roberval, and then followed his work on the properties of the Catenaria or the curve made by a chain fixed at both ends. In the course of this he was the first to observe that, by inverting this curve, the legitimate form of an arch is arrived at.