Shortly after Locke returned to England, he settled down in lodgings in the neighbourhood of what is now called Cannon Row, Westminster. But the fogs and smoke of London then, as now, were not favourable to persons of delicate health, and he seems to have been glad of any opportunity of breathing the country air. Amongst his places of resort were Parson's Green, the suburban residence of Lord Mordaunt, now Earl of Monmouth, and Oates, a manor-house, in the parish of High Laver, in Essex, the seat of Sir Francis and Lady Masham, situated in a pleasant pastoral country, about twenty miles from London. Lady Masham had become known to him as Damaris Cudworth, before his retreat to Holland, and it is plain that from the first she had excited his admiration and esteem. She was the daughter of Dr. Ralph Cudworth, Master of Christ's College, Cambridge, author of The True Intellectual System of the Universe, and of a posthumous work, still better known, A Treatise concerning Eternal and Immutable Morality. The close connexion which, in the latter years of his life, subsisted between Locke, the foremost name amongst the empirical philosophers of modern times, and the daughter of Cudworth, the most uncompromising of the a priori moralists and philosophers of the seventeenth century, may be regarded as one of the ironies of literary history. Damaris Cudworth, inheriting her father's tastes, took great interest in learning of all kinds, and specially in philosophy and theology. There was one point of community between her father and Locke besides their common pursuits, namely, the wide and philosophical view which they both took of theological controversies. Cudworth belonged to the small but learned and refined group of Cambridge Platonists or Latitudinarians, as they were called, which also numbered Henry More, John Smith, Culverwell, and Whichcote. Liberal and tolerant Churchmanship in those days, when it was so rare, was probably a much closer bond of union than it is now, and the associations which she had formed with her father's liberal, philosophical, and devout spirit must have helped to endear Locke to the daughter of Dr. Cudworth. During Locke's absence from England, Damaris Cudworth had married, as his second wife, Sir Francis Masham, an amiable and hospitable country gentleman, who seems to have occupied a prominent position in his county. With them lived Mrs. Cudworth, the widow of Dr. Cudworth, one little son, Francis, and a daughter by the former marriage, Esther, who was about fourteen when Locke commenced his visits to the family. From the first he seems to have had some idea of settling down at Oates, "making trial of the air of the place," than which, as Lady Masham tells us, "he thought none would be more suitable to him." After a very severe illness in the autumn of 1690, he spent several months with the Mashams, and appears then to have formed a more definite plan of making Oates his home. But, though his hospitable friends gave him every assurance of a constant welcome, he would only consent to regard it as a permanent residence on his own terms, which were that he should pay his share of the household expenses. With true kindness and courtesy, Sir Francis and Lady Masham, at last, in the spring of 1691, agreed to this arrangement, and "Mr. Locke then," says Lady Masham, "believed himself at home with us, and resolved, if it pleased God, here to end his days—as he did." Devoted and sympathetic friends, a pleasant residence, freedom from domestic or pecuniary cares, and the pure fresh air of the country seem to have afforded him all the enjoyment and leisure which we could have wished for him. After having had more than his share of the storms of life, he had at last found a quiet and pleasant haven wherein to enjoy the calm and sunshine of his declining years. Occasionally, and especially during the summer, he visited London, where, at first, he retained his old chambers at Westminster, moving afterwards to Lincoln's Inn Fields. But Oates was now his home, and it continued to be so to the end of his life.
Locke was always an attached friend, and we have seen already how many warm friendships he had formed in youth and middle age. At the present time, besides Limborch, Le Clerc, Lord Monmouth, and the Mashams, we may mention among his more intimate friends Lord Pembroke, the young Lord Ashley, Somers, Boyle, and Newton. Lord Pembroke (to whom the Essay is dedicated in what we should now regard as a tone of overwrought compliment) opened his town house for weekly meetings in which, instead of political and personal gossip, things of the mind were discussed. These conversations, "undisturbed by such as could not bear a part in the best entertainment of rational minds, free discourse concerning useful truths," were a source of great enjoyment to Locke during his London residence. It was through his introduction that Lord Pembroke, when sent on a special mission to the Hague, made the acquaintance, which afterwards ripened into friendship, of Limborch and Le Clerc.
The correspondence between Locke and Limborch, while Lord Pembroke was in Holland, reveals to us the curious fact that there was no organized carrying trade between England and Holland at that time. On returning, the Earl, or his Secretary, was commissioned to bring back a pound of tea and copies of the Acta Eruditorum. The tea must be had at any price. "I want the best tea," Locke writes to Limborch, "even if it costs forty florins a pound; only you must be quick, or we shall lose this opportunity, and I doubt whether we shall have another." The price that he was ready to pay for a pound of tea would be about 9l. at the present value of money. But tea at that time was regarded rather as a medicine than a beverage.
Young Lord Ashley, it will be recollected, had, like his father, been under the charge of Locke when a child. After being at school for some years at Winchester, and spending some time in travelling on the Continent, he was now again in London, living in his father's house at Chelsea. It is plain that the young philosopher saw a good deal of his "foster-father," as he called him, and they must often have discussed together the questions which were so interesting to them both. Ashley, moreover, who was already beginning to solve the problems of philosophy in his own way, addressed a number of letters to Locke, freely, but courteously and good-humouredly, criticising his master's views.
Sir John Somers, now Solicitor-General, and successively Attorney-General, Lord Keeper of the Great Seal, and Lord Chancellor, with the title of Lord Somers, had been known to Locke before his retirement to Holland. They were both of them attached to the Shaftesbury connexion, and hence, though Somers was nearly twenty years the junior, they had probably already seen a good deal of each other when William ascended the throne. On Locke's return to England, he found Somers a member of the Convention Parliament. The younger man, both when he was a rising barrister and a successful minister, seems frequently to have consulted the elder one, and Locke's principles of government, finance, and toleration must often have exerted a considerable influence both on his speeches and his measures. Nor had Locke any reason to be ashamed of his teaching. "Lord Somers," says Horace Walpole, "was one of those divine men who, like a chapel in a palace, remain unprofaned, while all the rest is tyranny, corruption, and folly." It was, perhaps, through Somers that Locke made the acquaintance of another great and wise statesman, Charles Montague, subsequently Lord Halifax, with whom, at least during the later years of his life, he had much political connexion, and by whom he was frequently called into counsel.
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 Locke, "to stop the translation and impression of the papers as soon as you can, for I desire to suppress them." Le Clerc thought more nobly and more justly that "one ought to risk a little in order to be of service to those honest folk who err only through ignorance, and who, if they get a chance, would gladly be disabused of their false notions." The letter was not published till after its author's death, and at first it appeared only in an imperfect form. In Bishop Horsley's edition of Newton it is printed complete. Newton's unpublished writings leave no doubt that he did not accept the orthodox doctrine of the Trinity, and it may have been his consciousness of this fact which made him so afraid of being known to be the author of what was merely a critical exercitation. But we must recollect that at this time Biblical criticism was unfamiliar to the majority of divines, and that to question the authenticity of a text was generally regarded as identical with doubting the doctrine which it was supposed to illustrate. One of the other subjects on which Locke and Newton corresponded was a parcel of red earth which had been left by Boyle, who died on Dec. 30, 1691, to Locke and his other literary executors, with directions for turning it into gold. Locke seems to have had some faith in the alchemistic process, but it is plain that Newton had none. He was satisfied that "mercury, by this recipe, might be brought to change its colours and properties, but not that gold might be multiplied thereby." Some workmen of whom he had heard as practising the recipe had been forced to other means of living, a proof that the multiplication of gold did not succeed as a profession. Occasionally, owing to Newton's nervous and irritable temper, which at one time threatened to settle down into a fixed melancholy, there seems to have been some misunderstanding of Locke on his part, but it is satisfactory to know that the two greatest literary men of their age in England, if not in Europe, lived, almost without interruption, in friendly and even intimate relations with each other.
The close intercourse between Boyle and Locke, which dated from their Oxford days, seems to have been kept up till the time of Boyle's death. Locke made a special journey to London to visit him on his death-bed, and was, as we have seen, left one of his literary executors. The editing of Boyle's General History of the Air had already been committed to Locke, and seems to have occupied much of his time during the year 1691.
Of Locke's less-known friends, Dr. David Thomas must have died between 1687, when there is a letter from him to Locke, and 1700, when Locke speaks of having outlived him. Sir James Tyrrell, another old college friend, usually spoken of in Locke's correspondence as Musidore, was in communication with him as late as April, 1704, the year of his death. He had, as already stated, been present at the "meeting of five or six friends" in Locke's chamber, which first suggested the composition of the Essay.
Edward Clarke, of Chipley, near Taunton, was another friend of old standing. He was elected member for Taunton in King William's second parliament, and from that time forward resided much in London. This circumstance probably deepened the intimacy between the two friends; at all events, during the remainder of Locke's life they are constantly associated. Locke advised Clarke as to the education of his children, one of whom, Betty, a little girl now about ten years old, seems to have been regarded by him with peculiar affection; in his letters he constantly speaks of her as "Mrs. Locke" and his "wife." The playful banter with which Locke treated his child friends affords unmistakable evidence of the kindness and simplicity of his heart.
William Molyneux, who for many years represented the University of Dublin in the Irish parliament, referred to in the second edition of the Essay as "that very ingenious and studious promoter of real knowledge, the worthy and learned Mr. Molyneux," "this thinking gentleman whom, though I have never had the happiness to see, I am proud to call my friend," first became acquainted with Locke in 1692. In his Dioptrica Nova, published in that year, he had paid Locke a graceful, if not an exaggerated, compliment. "To none do we owe, for a greater advancement in this part of philosophy," he said, speaking of logic, "than to the incomparable Mr. Locke, who hath rectified more received mistakes, and delivered more profound truths, established on experience and observation, for the direction of man's mind in the prosecution of knowledge, which I think may be properly termed logic, than are to be met with in all the volumes of the ancients. He has clearly overthrown all those metaphysical whimsies which infected men's brains with a spice of madness, whereby they feigned a knowledge where they had none, by making a noise with sounds without clear and distinct significations." Locke was pleased with the compliment, and a letter acknowledging the receipt of Molyneux's book was the beginning of a long correspondence between them, which ended only with the early death of Molyneux, at the age of forty-two, in 1698. For nearly six years the friends, though in constant correspondence, had never seen each other, Molyneux residing in Dublin, and suffering, like Locke, from feeble health, which prevented him from crossing the Channel. But the feeling of affection seems soon to have become as intense, notwithstanding Aristotle's dictum that personal intercourse is essential to the continuance of friendship, as if they had lived together all their lives. In his second letter to Molyneux, dated Sept. 20, 1692, Locke says:—"You must expect to have me live with you hereafter, with all the liberty and assurance of a settled friendship. For meeting with but few men in the world whose acquaintance I find much reason to covet, I make more than ordinary haste into the familiarity of a rational inquirer after and lover of truth, whenever I can light on any such. There are beauties of the mind as well as of the body, that take and prevail at first sight; and, wherever I have met with this, I have readily surrendered myself, and have never yet been deceived in my expectation." Molyneux had thought of coming over to England on a visit to Locke in the summer of 1694. Locke, in a letter written in the following spring, after deprecating the risks to which his journey might expose him adds:—"And yet, if I may confess my secret thoughts, there is not anything which I would not give that some other unavoidable occasion would draw you into England. A rational, free-minded man, tied to nothing but truth, is so rare a thing that I almost worship such a friend; but, when friendship is joined to it, and these are brought into a free conversation, where they meet and can be together, what is there can have equal charms? I cannot but exceedingly wish for that happy day when I may see a man I have so often longed to have in my embraces.... You cannot think how often I regret the distance that is between us; I envy Dublin for what I every day want in London." In a subsequent letter, written in 1695, he writes:—"I cannot complain that I have not my share of friends of all ranks, and such whose interest, assistance, affection, and opinions too, in fit cases, I can rely on. But methinks, for all this, there is one place vacant that I know nobody would so well fill as yourself; I want one near me to talk freely with "de quolibet ente," to propose to the extravagancies that rise in my mind; one with whom I would debate several doubts and questions to see what was in them." Thomas Molyneux, the brother of William, a physician practising in Dublin, had met Locke during his stay in Holland. They shared a common admiration for Sydenham, and the correspondence with William Molyneux revived their friendship, though it never attained to nearly the same proportions as that between Locke and the other brother. A passage on what may be called the Logic of Medicine, in one of Locke's letters to Thomas Molyneux, is worth quoting:—"What we know of the works of nature, especially in the constitution of health and the operations of our own bodies, is only by the sensible effects, but not by any certainty we can have of the tools she uses or the ways she walks by. So that there is nothing left for a physician to do but to observe well, and so, by analogy, argue to like cases, and thence make to himself rules of practice."