What had happened during the evening--what had happened after their conversation in Gordon's room?
He had gone to Mrs.Vivian's--what had happened there?
Bernard found it difficult to believe that he had gone there simply to notify her that, having talked it over with an intimate friend, he gave up her daughter, or to mention to the young lady herself that he had ceased to desire the honor of her hand.

Gordon alluded to some definite occurrence, yet it was inconceivable that he should have allowed himself to be determined by Bernard's words--his diffident and irresponsible impression.

Bernard resented this idea as an injury to himself, yet it was difficult to imagine what else could have happened.

There was Gordon's word for it, however, that there was no "traceable" connection between the circumstances which led to his sudden departure and the information he had succeeded in extracting from his friend.

What did he mean by a "traceable" connection?
Gordon never used words idly, and he meant to make of this point an intelligible distinction.