The club of course knew that Lord Nidderdale was the accepted suitor of the rich man's daughter,--accepted, that is, by the rich man himself,--and the club knew also that the rich man's daughter had tried,--but had failed,--to run away with Sir Felix Carbury. There is nothing like wiping out a misfortune and having done with it. The presence of Lord Nidderdale was almost an assurance to the club that the misfortune had been wiped out, and, as it were, abolished. 
The club of course knew that Melmotte's daughter had tried to run away with Sir Felix Carbury; and Lord Nidderdale's presence was an assurance that the misfortune had been wiped out.
