This whole conversation in ch 10 with Miss Bingley being so solicitous of Mr Darcy's letter writing is hysterical. My favorite observation: "How can you contrive to write so even?" (snort!) He tries to stem the flow by making negative statements ("You are mistaken" - "I have already told her so") or just silence, but Miss Bingley will not be deterred! It's a very funny scene to read, but if I were Darcy I don't know that I could refrain from being really rude in the face of such obsequiousness.