"Did you hear some one cough, Arline?" she asked anxiously.
"Yes," replied Arline, who had joined her. "The sound came from in here, didn't it?"
"So I imagined," declared Grace in a puzzled tone. "Perhaps it came from the hall. No one could have escaped from here before I reached the door without my hearing them. It startled me, because we had been talking so confidentially. I glanced in as we passed the door when we went into the living room and there wasn't a soul in sight. Whoever coughed a few moments ago must have slipped into the room and slipped out again."
"Then, whoever it is has heard the very things we didn't wish known!" exclaimed Arline in consternation. "Now I can't carry out any of my plans. How perfectly dreadful!"
"Perhaps it was Mrs. Elwood," said Grace hopefully.
"Mrs. Elwood is far too stout to walk so lightly and vanish so rapidly," discouraged Arline. "I—it—must have been some one who was trying to hear."
"If that is the case, the person is in this house and must be found and sworn to secrecy," said Grace sternly. "I am afraid we were talking too loudly. However, the person may have only come as far as the door, then passed on upstairs. Suppose we go up and ask all the girls. We shall feel better satisfied, and they won't object to being interviewed."
But all efforts to locate the accidental or intentional listener failed. Many of the girls had not yet come in from their classes, and those whom Grace found in their rooms had evidently been there for some time. Kathleen West was among those still out. Miss Ainslee informed her visitors of this fact with an unmistakable sigh of relief that Grace interpreted with a slight smile. As she went slowly down the stairs to the living room, followed by Arline, whose baby face wore an expression of deepest gloom, the door bell rang and the maid admitted the newspaper girl. She swept past the two juniors who stood at the foot of the stairs without the slightest sign of recognition, and neither girl saw the look of triumph that animated her face the instant she had turned her back upon them and hurried up the stairs.
"What shall we do?" asked Arline as once more they seated themselves at the library table opposite each other.
"We can't do anything until we find the girl who listened, and the question is how are we to find her?" Grace made a little gesture of despair.