The acquaintance between Locke and Newton, of whom Newton was the junior by more than ten years, most probably began before Locke's departure to Holland. Both had then for some time been members of the Royal Society, and both were friends of Hoyle. The first positive evidence, however, that we have of their relations is afforded by a paper, entitled "A Demonstration that the Planets, by their gravity towards the Sun, may move in Eclipses," and endorsed in Locke's handwriting, "Mr. Newton, March, 1689." In the summer or autumn of the same year, probably, was written the epistle to the reader prefixed to the _Essay_. In that occurs the following passage, expressing no doubt Locke's genuine opinion of the great writers whom he names:--"The Commonwealth of learning is not at this time without master-builders, whose mighty designs in advancing the sciences will leave lasting monuments to the admiration of posterity; but every one must not hope to be a Boyle or a Sydenham, and in an age that produces such masters as the great Huygenius and the incomparable Mr. Newton, with some other of that strain, 'tis ambition enough to be employed as an under-labourer in clearing ground a little, and removing some of the rubbish that lies in the way to knowledge." Locke interested himself long and warmly in attempting to obtain for Newton some lucrative appointment in London. Newton's letters occasionally betray querulousness, but there can be no reason to suppose that Locke at all flagged in his efforts, and ultimately, with the assistance of Lord Monmouth, Lord Halifax, and others, they proved successful. Newton was, in course of time, appointed Warden, and then Master of the Mint. In January, 1690-91, the philosopher and the mathematician met at Oates. Their conversation there probably turned chiefly on theological topics, as was the case with most of their correspondence afterwards. Newton was greatly interested not only in theological speculation, but in the interpretation of prophecy and Biblical criticism, on both of which subjects works by him are extant. In 1690 he wrote a manuscript letter to Locke, entitled "An Historical Account of Two Notable Corruptions of Scripture in a Letter to a Friend," the texts criticised being 1 John v. 7, and 1 Timothy iii. 16. The corruption of the former of these texts is now almost universally, and that of the latter very generally, acknowledged; but so jealous of orthodoxy, in respect of anything which seemed to affect the doctrine of the Trinity, was public opinion at that time, that Newton did not dare to publish the pamphlet. Locke, who was meditating a visit to Holland, was, by Newton's wish, to have taken it over with him, and to have had it translated into French, and published anonymously. But the intended visit fell through, and Locke sent the manuscript over to Le Clerc. So timid, however, was Newton, that he now tried to recall it. "Let me entreat you," he writes to