He would not quarrel with that affectionate, hot-headed brother worker, but for himself that chapter of his life was finished, and he turned the page. In the very same year he gave to a thankless world his ‘Elements of Philosophy;’ and he again refused Frederick the Great’s invitation to exchange persecuting Paris for the Presidency of the Berlin Academy. But there was no reason why he should not escape from his troubles for a time and become Frederick’s visitor. In 1762 he went to Berlin for two months, and found the great King a clever, generous, and devoted friend. But though he continued to beg d’Alembert to stay with him permanently, and was lavish of gifts and promises, the wise and judicious visitor was wholly proof against the royal blandishments. In the same year he refused a yet more dazzling offer--to be tutor to Catherine the Great’s son. He had already in Paris, not only ties, which might be broken, but _a_ tie, which he found indissoluble. In 1765, three years after Catherine’s offer had been made and declined, d’Alembert, when he was forty-eight years old, was attacked by a severe illness, which, said his accommodating doctor, required larger and airier rooms than those in his good old nurse’s home. He was moved from the familiar Rue Michel-Lecomte to the Boulevard du Temple. There Mademoiselle de Lespinasse joined him and nursed him back to health. In all the story of d’Alembert’s life, in that age of unbridled licence, no woman’s name is connected with his save this one’s. Fifteen years earlier he had made the acquaintance of Madame du Deffand. To the blind old worldling, who loved Horace Walpole and wrote immortal letters, he stood in the nature of a dear and promising son. For many years he was always about her house. His wit and his charm, seasoned by a gentle spice of irony and a delightful talent for telling stories and enjoying them himself, naturally endeared him to the old woman whose one hell was boredom. On his side, he came because he liked her, and stayed because he loved Mademoiselle de Lespinasse. The history of that _ménage_ of the brilliant, impulsive, undisciplined girl, with her plain face and her matchless charm, and of the blind old woman she tended, deceived, and outwitted, has been told in fiction as well as in history. How when Madame du Deffand was asleep, her poor companion held for herself reunions of the bright, particular stars of her mistress’s firmament, and how the old woman, rising a little too early one day, came into the room and with her sightless eyes saw all, is one of the familiar anecdotes of literature.