In 1695 the question of the reform of the currency was prominently before the nation (Macaulay, History, chap. xxi.). Montagu, Newton's friend, was chancellor of the exchequer, and he, Somers the lord-keeper, Newton, and Locke met in frequent conference to discuss plans for remedying the evil without altering the standard. Montagu brought in a bill for the reform, which received the royal assent on 21 Jan. 1696. Meanwhile the wardenship of the mint became vacant, and Montagu on 19 March 1696 offered it to Newton, by whom it was accepted. The mint had been a nest of idlers and jobbers. ‘The ability, the industry, and the strict uprightness of the great philosopher speedily produced a complete revolution throughout the department which was under his direction’ (ib. chap. xxii.). Montagu's successful reform was aided to no small degree by the energy of the warden. ‘Well had it been for the public,’ says Haynes, ‘had he acted a few years sooner in that situation’ (see also Ruding, Annals of the Coinage). A letter to Flamsteed, which has given rise to much controversy, written in 1699, while the recoinage was in progress, may be mentioned here. In it Newton says: ‘I do not love to be printed on every occasion, much less to be dunned and teased by foreigners about mathematical things, or to be thought by our own people to be trifling away my time about them when I should be about the king's business’ (Baily, Life of Flamsteed, p. 164; Brewster, Life of Newton, ii. 149; Edleston, Cotes Corr. n. p. lxi; Macaulay, History, chap. xxii.). De Morgan, however, in opposition to Newton's other biographers, expresses regret that Newton ever accepted office under the crown, and suggests that from the time of his settling in London his intellect underwent a gradual deterioration. If, he says, after having piloted the country through a very difficult and, as some thought, impossible operation, ‘he had returned to the university with a handsome pension’ and his mind free to make up again to the ‘litigious lady,’ he would, to use his own words, have taken ‘another pull at the moon;’ and ‘we suspect Clairant would have had to begin at the point from which Laplace afterwards began’ (Newton his Friend and his Niece, p. 149).
In 1699 he became master of the mint, a member of the council of the Royal Society, and a foreign associate of the French Academy. Next year he appointed Whiston his deputy in the Lucasian chair, ‘with the full profits of the place.’ Whiston began his lectures on 27 Jan. 1701, and at the end of the year, when Newton resigned the professorship and his fellowship, he was elected to succeed him as professor. The same year Newton's ‘Scala Graduum Caloris,’ the foundation of our modern scale of temperature, was read (Phil. Trans. March and April). Newton had not represented the university in the parliament of 1690, but in November 1701 he was again elected, holding the seat till July 1702, when parliament was dissolved. The same year his ‘Lunæ Theoria’ was published in Gregory's ‘Astronomy.’ The following year (30 Nov. 1703) he was elected president of the Royal Society, and to this office he was annually re-elected for twenty-five years.
In February 1704 there appeared, appended to the ‘Optics,’ which was only then issued, two very important mathematical papers, most of which had been communicated to Barrow in 1668 or 1669. The one entitled ‘Enumeratio Linearum Tertii Ordinis’ (Ball, Short Hist. of Math. p. 346; Trans. Lond. Math. Soc. 1891, xxii. 104–43) was practically the same as the ‘De Analysi per Equationes Numero Terminorum Infinitas’ (first printed in 1711), the substance of which was communicated by Barrow to Collins in 1669. The second part of the appendix—the ‘Tractatus de Quadratura Curvarum’—contains a description of Newton's method of fluxions.
In 1705 Newton, as president of the Royal Society, became involved in the difficulties relating to the publication of Flamsteed's observations, while some remarks in a review of the tract ‘De Quadratura Curvarum,’ published in the ‘Acta Lipsica’ 1 Jan. 1705, led to the controversy between Newton and Leibnitz on the priority of discovery of the fluxions.
These two controversies were pursued with much heat, and greatly embittered Newton's life for many years. That with Flamsteed lasted from 1705 to 1712; while that with Leibnitz lasted from 1705 until 1724.
Flamsteed was appointed astronomer royal (astronomical observator) in 1675, and began a correspondence with Newton about 1681 in the course of a discussion about the great comet of 1680—Halley's comet. He supplied Newton with valuable information of various matters during the preparation on the first edition of the ‘Principia,’ 1685–6 (General Dictionary, vii. 793). Their correspondence was renewed in 1691, when Newton urged Flamsteed to publish the observations he had accumulated during the past fifteen years. Flamsteed declined, and put down Newton's suggestions to Halley, with whom he had quarrelled (Baily, Life of Flamsteed, p. 129). In 1694 when Newton
