king's pardon, approving of the plan, and enclosing an order for money. Faccio revealed the plot to his friend Gilbert Burnet, whom he accompanied to Holland in 1686 in order to explain it to the prince. To reward him it was resolved to create for Faccio, whose abilities were certified by Huyghens, a mathematical professorship, with a house and a commencing salary of twelve hundred florins. The prince also promised him a private pension. Some delay occurring, Faccio got leave to pay a visit to England in the spring of 1687, where, he writes, ‘being mightily pleased with this nation, and with the English language, and having been ill at Oxford, I did not care to return to the Hague; where, by the imprudence of others, I might have become too much exposed to the resentment of two kings and of the count at once; but stayed in England till the Prince of Orange was in full possession of these kingdoms.’ He was admitted a fellow of the Royal Society, 2 May 1688 (Thomson, Hist. of Roy. Soc. appendix iv. p. xxviii). Having obtained posts for some of his countrymen in the English and Dutch service, Faccio ‘found it necessary for his own rest’ to leave England for a while. He became travelling tutor to the eldest son of Sir William Ellis and a Mr. Thornton, and resided during part of 1690 at Utrecht. Here he met Edmund Calamy, who writes of him that at that time he was generally esteemed to be a Spinozist. In the autumn of 1691 Faccio returned to England. He was in Switzerland in 1699, 1700, and 1701 (see his letter in Seward, Anecdotes of Distinguished Persons, 4th edit. ii. 190–215).
Faccio was concerned in the famous quarrel between Newton and Leibnitz. He had visited Newton at Cambridge in November 1692. Newton gave him money, and offered to make him a regular allowance on the condition of his permanently residing at Cambridge (letter of Newton, dated 14 March 1692–3, in Nichols, Illustr. of Lit. iv. 58). Faccio was unworthy of his patron. Hearne says that he was ‘a sceptick in religion, a person of no virtue, but a mere debauchee,’ and he relates how Faccio ‘got by his insinuation and cunning a vast sum of money’ from his pupil the Duke of Bedford (Collections, Oxf. Hist. Soc., ii. 244). Faccio alleged that he had convinced Newton of certain mistakes in the ‘Principia’ (Rigaud, Historical Essay, p. 100; Edinburgh Transactions, 1829, xii. 71). He puts himself on a par with Newton, and in a letter to Huyghens, dated 1691, writes that it is really unnecessary to ask Newton to prepare a new edition. ‘However,’ he adds, ‘I may possibly undertake it myself, as I know no one who so well and thoroughly understands a good part of this book as I do.’ Huyghens gravely wrote on the margin of this letter ‘Happy Newton’ (Kemble, State Papers and Correspondence, pp. 426–7). When Leibnitz sent a set of problems for solution to England he mentioned Newton and failed to mention Faccio among those probably capable of solving them (ib. p. 428). Faccio retorted by sneering at Leibnitz as the ‘second inventor’ of the calculus in a tract entitled ‘Lineæ brevissimæ descensus investigatio geometrica duplex, cui addita est investigatio geometrica solidi rotundi in quo minima fiat resistentia,’ 4to, London, 1699 (p. 18). In replying to Faccio (Acta Eruditorum, 1700, p. 203) Leibnitz appealed to Newton himself as having admitted the independent discovery. Faccio sent a reply to the editors of the ‘Acta Eruditorum,’ but they refused to print it on the ground of their aversion to controversy (ib. 1701, p. 134). Finally he stirred up the whole Royal Society to take a part in the dispute (Brewster, Memoirs of Sir I. Newton, 2nd edit. ii. 1–5).
Faccio continued to reside in London as a teacher of mathematics. He entered into partnership with the brothers Peter and Jacob de Beaufré, French watchmakers in London, and obtained a fourteen years' patent for the sole use in England of his invention relating to rubies (London Gazette, 11 May 1704). In March 1705 he exhibited specimens of watches thus jewelled to the Royal Society (Original Letters of Eminent Literary Men, Camd. Soc. xxiii. 317–18). About this time Faccio associated himself with the Camisards, or ‘French prophets,’ becoming their chief, and committing their warnings to writing. The government suspected him of contriving some deep political scheme. At last Faccio and two of his brethren were prosecuted at the charge of the French churches in London, and condemned by the queen's bench to the pillory as common cheats and impostors. On 2 Dec. 1707 Faccio stood on a scaffold at Charing Cross, with an inscription on his hat describing him as an accomplice in spreading ‘wicked and counterfeit prophecies.’ By the influence of the Duke of Ormonde, to whose brother, Lord Arran, Faccio had been tutor, he was saved from the violence of the mob (Luttrell, Relation of State Affairs, 1857, vi. 240). He next started on an expedition to convert the world, wandered through Germany, went into Asia, and in the end drifted back to England. He was in London in May 1712. Eventually he retired to Worcester, where he formed some congenial friendships, and busied himself with scientific pur-
