What the deuce M.de Bellegarde was smiling at he was at a loss to divine.

M.
de Bellegarde's smile may be supposed to have been, for himself, a compromise between a great many emotions.

So long as he smiled he was polite, and it was proper he should be polite.

A smile, moreover, committed him to nothing more than politeness, and left the degree of politeness agreeably vague.

A smile, too, was neither dissent--which was too serious--nor agreement, which might have brought on terrible complications.