Often, even before the arrival of the old pensioner, she was at work dictating a letter, usually to Horace Walpole, occasionally to Madame de Choiseul or Voltaire.  Her letters to Voltaire are enchanting; his replies are no less so; and it is much to be regretted that the whole correspondence has never been collected together in chronological order, and published as a separate book.  The slim volume would be, of its kind, quite perfect.  There was no love lost between the two old friends; they could not understand each other; Voltaire, alone of his generation, had thrown himself into the very vanguard of thought; to Madame du Deffand progress had no meaning, and thought itself was hardly more than an unpleasant necessity.  She distrusted him profoundly, and he returned the compliment.  Yet neither could do without the other:  through her, he kept in touch with one of the most influential circles in Paris; and even she could not be insensible to the glory of corresponding with such a man.  Besides, in spite of all their differences, they admired each other genuinely, and they were held together by the habit of a long familiarity.  The result was a marvellous display of epistolary art.  If they had liked each other any better, they never would have troubled to write so well.  They were on their best behaviour—­exquisitely courteous and yet punctiliously at ease, like dancers in a minuet.  His cajoleries are infinite; his deft sentences, mingling flattery with reflection, have almost the quality of a caress.  She replies in the tone of a worshipper, glancing lightly at a hundred subjects, purring out her ‘Monsieur de Voltaire,’ and seeking his advice on literature and life.  He rejoins in that wonderful strain of epicurean stoicism of which he alone possessed the secret:  and so the letters go on.  Sometimes one just catches the glimpse of a claw beneath the soft pad, a grimace under the smile of elegance; and one remembers with a shock that, after all, one is reading the correspondence of a monkey and a cat.

Madame du Deffand’s style reflects, perhaps even more completely than that of Voltaire himself, the common-sense of the eighteenth century.  Its precision is absolute.  It is like a line drawn in one stroke by a master, with the prompt exactitude of an unerring subtlety.  There is no breadth in it—­no sense of colour and the concrete mass of things.  One cannot wonder, as one reads her, that she hardly regretted her blindness.  What did she lose by it?  Certainly not

      The sweet approach of even or morn,
    Or sight of vernal bloom, or Summer’s rose;