Jane Austen and Mary Crawford – which is which?

Emily Auerbach in Searching for Jane Austen states that “Austen gives Mary Crawford the breezy tone and sharp bite of her own letters” and asks  “Which of the following is from an Austen letter and which is a remark by Mary Crawford?”:

“What a difference a vowel makes? If his rents were but equal to his rants.”

“It is a vile world, we are all for self and I expect no better from of us. But though Better is not to be expected, Butter may, at least from Mrs Clements cow”

“Expect an agreeable letter; for not being overburdened with subject – (having nothing at all to say)- I shall have no check to my genius from beginning to end”.

“It is impossible to put an hundredth part of my great mind on paper”.

Its not too difficult but a very interesting comparison.