Why he must have interpreted that as a reference to his own wealth and a blatant encouragement. Not surprising then that he moved closer. Wonder if he was aware of doing so?

Next he is quite obviously focusing on her and trying to find out where she learnt to be so brainy. Her response to his utterance sure served as a damper. Poor Darcy has to retreat and grasp for a newspaper to hint at his 'indifference'. The smile is no more.