This is an ‘office copy’ of the letter, written by one of Locke’s amanuenses, Locke being careful to keep a record of both sides of his correspondence. Locke's correspondent was Thomas Molyneux (1661-1733), one of the most prominent doctors in Ireland, and a fellow of both the Royal Society and the Dublin Philosophical Society, whom Locke had known since they met in Leiden in 1684. The letter laments the death of Molyneux’s brother, William Molyneux (1656-98), a natural philosopher who, as founder of the Dublin Philosophical Society, is regarded as the founder of modern science in Ireland.
William Molyneux had sent a gift copy of his work on optics, Dioptrica nova, to Locke in 1692 which began a friendship and correspondence. Molyneux's criticisms and suggestions had an influence on the second (1694) and later editions of Locke’s Essay Concerning Human Understanding. In this letter we can see something of the intellectual exchange in Locke’s correspondence.
The letter will join the papers of John Locke in the Bodleian Library, and a substantial part of Locke’s library. MSS.Locke includes the philosopher’s journals, letters, notebooks, accounts and papers, mostly purchased from the 4th earl of Lovelace in 1947. Further manuscripts were given to the Library by Paul Mellon, 1960-71. Among the Locke papers are four letters to William Molyneux, 1688-96 (MS. Locke c. 16, fols. 92-9), and two to Sir Thomas Molyneux, 1699-1700 (MS. Locke c. 16, fols. 88-91).
Locke’s correspondence with Molyneux has long been recognised as important. The original letter still exists, but it is not readily accessible, being part of a private manuscript collection with limited access to researchers. The copy is important too because the paper stock on which it was written can help with dating other works. James Dorington became Locke’s amanuensis in January 1699; scholars are unsure of his handwriting, and this item should help to make a firm identification.