“Second, because the rascals most likely selected the very couple from whose servant they had got the information, knowing that inquiries would subsequently be made, and that the servant could keep them still further informed as to what investigations were being made and what was suspected.” “By Jove, there is something in that, Nick, also.” “And that is why I suspect a servant in the Ringold house, some one who overheard Mrs. Waldmere and Mrs. Ringold discussing their costumes.” “Why didn’t you question the Ringolds about their servants last night, then?” “Because I had rung them up at two o’clock in the morning,” said Nick. “If the servant heard the bell, he, or she, as the case may be, would have suspected my mission and might have been in a position to play the eavesdropper without being detected. I didn’t want my suspicion discovered. It would put the servant on his guard, and us at a corresponding disadvantage.” “I see,” Chick nodded. “It was a wise precaution.” “You had better go over there this morning, however, and talk with Mrs. Ringold,” Nick added. “Your identity and mission may not be suspected, while the servant might have seen Patsy and me last night when we passed through the lighted hall. Find out who is employed in the house and what is known about them.” “I’ve got you,” said Chick. “Leave it to me.” “Aren’t you overlooking one point, chief?” questioned Patsy, who had been listening to the foregoing. “What point is that, Patsy?” “The crooks may have learned from the costumer, or from one of his clerks, what costume Mrs. Waldmere intended wearing.” “I have thought of that, but it is quite improbable,” said Nick. “They would not have known, to begin with, that Mrs. Waldmere had any intention of hiring a costume from Perrot. Furthermore, costumers of his high standing do not betray their patrons, and crooks know it and would have sought elsewhere for the desired information.” “Gee! I guess you’re right, chief, after all.” “I think my other suspicion is the correct one.” “I’ll run over to Brooklyn, then, at once,” said Chick. “Do so,” Nick replied, rising. “I’ll pay Perrot a in the meantime and see what I can learn from him. The costume worn by Mrs. Waldmere must have been previously seen by the duplicate Night, whoever she was, or she could not have duplicated it. We’ll look into that. You may go with me, Patsy.” CHAPTER IV. A SCARLET THREAD. It was eleven o’clock when Nick Carter and Patsy entered the extensive business establishment of the leading New York costumer, Monsieur Jules Perrot, in Fifth Avenue. Perrot himself, a suave and polished Frenchman, happened to be conspicuously in evidence and hastened to meet them, bowing and smiling and rubbing his hands. Nick addressed him quietly and introduced himself, evoking ejaculations and a more intent and interested stare from Perrot, which turned to an expression of gravity when the detective stated his mission.