Of course, I knew there was no reason why Whittington should be in that room rather than in any other less reason, in fact, for the betting would be on his being in one of the reception-rooms downstairs.
Whittington had plenty of reasons to be in that room.  
mnli hypothesis: Whittington had plenty of reasons to be in that room.   premise: Of course, I knew there was no reason why Whittington should be in that room rather than in any other less reason, in fact, for the betting would be on his being in one of the reception-rooms downstairs.