"Where are you going?" Grace asked.
"To 162 West 57th Street." Suddenly he took his wallet from his pocket, snatched a second card from it, and after looking at it for a moment, gave an exclamation of delighted surprise.
"What is it?" Grace asked quickly.
He thrust the card into her hand. Grace glanced at it, without quite understanding what it meant.
"I don't see what you mean," she exclaimed. "The thing is clear enough. The card I have just given you belongs to Miss Ruth Morton."
"I see that, but——"
"Then surely you must see that Miss Morton's apartment also is on Fifty-seventh Street, and just two doors from the address of Miss Marcia Ford!"
CHAPTER XIII
Duvall, upon discovering that the address of Miss Marcia Ford was on West 57th Street, but two doors from the building in which the Morton apartment was located, began to feel that he was on the right track. He had known, ever since his first day upon the case, that the mysterious messages found in Ruth Morton's bedroom had been placed there by some ingenious but perfectly natural means. The apparition that had so startled the girl upon her last night at the flat was capable, of course, of some reasonable explanation. When he left Mr. Baker in the morning his plan had been to go to Mrs. Morton's apartment and once more investigate all possible means of entrance, hoping that, by finding out how the messages were delivered, he might also be able to find out by whom. It was for this reason that he had asked Mrs. Morton for the key to the apartment.
Now the question seemed in a fair way to being answered for him. The fact that this girl's room was located so near to the Mortons' apartment could not be a mere coincidence. There must be, between her room and the Morton flat some means of communication, although of what nature he could not now surmise. Fully convinced, however, that he might very soon find out, he hurried up to Fifty-seventh Street and walked along until he reached No. 162.