Lady Mary’s tongue made her many enemies in society, and when her tongue failed her she brought her pen into action.  Her love of scandal must have gone far to make her unpopular, and if her letters to her sister at Paris had been published she would have found herself with scarcely a friend in the world.

Correspondence between Lady Mary, from London or Twickenham, to her sister, the Countess of Mar, at Paris, was a very one-sided affair.  This was, in part, owing to the fact that Lord Mar was, of course, suspect, and that letters to him or to members of his family and household were (in all probability) intercepted in this country.  Lady Mary, who had suspected this more than once, became more and more convinced that her suspicions were justified.  “I have writ to you at least five-and-forty letters, dear sister, without receiving any answer, and resolved not to confide in post-house fidelity any more, being firmly persuaded that they never came to your hands, or you would not refuse one line to let me know how you do, which is and ever will be of great importance to me.”  That was written at Christmas, 1722, and though in the meantime Lady Mary heard from her sister, she realised that if she wanted her letters to arrive she must be careful as to the topics upon which she discoursed.  “Letters are so surely opened, I dare say nothing to you either of our intrigues or duels, both of which would afford great matter of mirth and speculation.”  The difficulties of communication did not decrease.  “I have writ to you twice since I received yours in answer to that I sent by Mr. de Caylus,” she remarked a little later; “but I believe none of what I send by the post ever come to your hands, nor ever will while they are directed to Mr. Waters, for reasons that you may easily guess.  I wish you would give me a safer direction; it is very seldom I can have the opportunity of a private messenger, and it is very often that I have a mind to write to my dear sister.”

Lady Mary, of course, often stayed in London, and in her correspondence are many references to her friends and her doings.

“Operas flourish more than ever, and I have been in a tract of going every time,” she wrote to her sister in April, 1723.  “The people I live most with are none of your acquaintance; the Duchess of Montagu excepted, whom I continue to see often.  Her daughter Belle is at this instant in the paradisal state of receiving visits every day from a passionate lover, who is her first love; whom she thinks the finest gentleman in Europe, and is, besides that, Duke of Manchester.  Her mamma and I often laugh and sigh reflecting on her felicity, the consummation of which will be in a fortnight.  In the mean time they are permitted to be alone together every day and all the day.”

Mary’s very best vein is the following letter, written about the same time, and also addressed to her sister: