In reading chapter 24 yesterday, I noticed something interesting at the beginning of the chapter. Henry and Mary are discussing his plans for the next few weeks, and he says he intends to make Fanny fall in love with him, of course. What struck me was this: it seems that Mary not only was aware of him playing with Maria's (and Julia's) affections, but that he had discussed what he was doing with her at the time.
“Fanny Price! Nonsense! No, no. You ought to be satisfied with her two cousins.”
Now, maybe I'm just reading something into this that JA never intended, but there's something about the phrasing, when he talks above about needing to engage his mind: "I am grown too old to go out more than three times a week; but I have a plan for the intermediate days, and what do you think it is?”
“To walk and ride with me, to be sure.”
“Not exactly, though I shall be happy to do both, but that would be exercise only to my body, and I must take care of my mind. Besides, that would be all recreation and indulgence, without the wholesome alloy of labour, and I do not like to eat the bread of idleness."
Mary protests, but not very hard. He's used to getting his way and playing with a woman's affections and leaving "destruction" of a sort in his wake, something she acknowledged earlier in the book. It almost seems that he plans his conquests with his sister ahead of time. And maybe I've read MP too many times!