...is pretty icky, especially as he is giving free rein to it at the moment he is supposed to be encouraging Jack to court Lydia for a wife. I think Jack's reply "And which is to be mine, sir, the niece or the aunt." is masterful, as it is not just a funny reversal, but while playing dumb, Jack still manages to slyly skewers his father's lechery.

Jack further "innocent" comments even provoke his father into statements which inadvertently highlight the older man's lechery (when Sir A fails to see the applicability to himself of his own description of "anything old or ugly" vis a vis Lydia) and the older man's own defiance of parental tyranny (when Sir A at first boasts of his own defiance of his own father, before catching himself).