These, it would appear, Catharine Trotter had never abandoned, but she applied herself to them closely at Salisbury, where she made some superior acquaintances. One of these was John Norris of Bemerton, whose _Theory of an Ideal and Intelligible World_ had just made some sensation. By the intermediary of George Burnet she came in touch with some of the leading French writers of the moment, such as Malebranche and Madame Dacier. There is a French poet, unnamed, who understands English, but he is gone to Rome before he can be made to read _The Fatal Friendship_. Meanwhile, Catharine Trotter's obsession with the ideas of Locke was giving some anxiety to her friends. That philosopher had published his famous _Essay on the Human Understanding_ in 1690, and it had taken several years for the opposition to his views, and in particular to his theological toleration, to take effect. But in 1697 there were made a number of almost simultaneous attacks on Locke's position. The circle at Salisbury was involved in them, for one of these was written by Norris of Bemerton, and another is attributed to a member of the Burnet family. Catharine Trotter, who had studied Locke's later works with enthusiastic approval, was scandalised by the attacks, and sat down to refute them. This must have been in 1701. Although the intellectual society of Salisbury was prominent in taking the conservative view of Locke, our bluestocking could not refrain from telling Mrs. Burnet what she had done, nor from showing her treatise to that friend under vows of confidence. But Mrs. Burnet, who was impulsive and generous, could not keep the secret; she spoke about it to the Bishop, and then to Norris of Bemerton, and finally (in June 1702) to Locke himself. Locke was at Oates, confined by his asthma; he was old and suffering, but still full of benevolence and curiosity, and he was graciously interested in his remarkable defender at Salisbury. As he could not himself travel, he sent his adopted son to call on Catharine Trotter, with a present of books; this was Peter King, still a young man, but already M.P. for Beer Alston, and later to become Lord Chancellor and the first Lord King of Ockham. George Burnet, writing from Paris, had been very insistent that Catharine should not publish her treatise, but she overruled his objections, and her _Defence of Mr. Locke's Essay on the Human Understanding_ appeared anonymously in May 1702. People were wonderfully polite in those days, and Locke himself wrote to his "protectress" a charming letter in which he told her that her "_Defence_ was the greatest honour my Essay could have procured me." She sent her _Defence_ to Leibnitz, who criticised it at considerable length:--[3]