ite sure," she spoke with
uncertainty, and Kent knew that she lied. His heart sank.

"Did he swallow any medicine in your presence?"

She shook her head vigorously. "No, he did not."

Kent lowered his voice. "Did you see him take Mrs. Brewster's aconitine
pills off the hall table?"

Helen shifted her gaze to his face and then back to her ever restless
hands. "No," she said. "I did not see him take the pills."

Kent studied her in a silence which, to her, seemed never-ending.

"I want the true answer to this question," he announced with meaning
emphasis. "Why did Jimmie go in disguise to your house on Monday night?"

Helen blanched. "How should I know," she muttered evasively. "He--he
didn't come to see me--the admission was barely above a whisper.

"But you know what transpired in your house on Monday night?" demanded
Kent eagerly.

His question met with no response, and he repeated it, but still the
girl remained silent. Kent gave her a moment's grace, then drawing out
the unaddressed envelope from his pocket he held it toward her. A low
cry broke from her, and her expression changed as she caught sight of
the broken seal.

"You have opened it!"

"Not yet," Kent held the envelope just beyond her reach. "I will only
give it to you with the understanding that you open the envelope now in
my presence and let me see its contents."

Helen drew back, then impulsively extended her hand.

"I agree," she said. "Give me the envelope."

"Stop!" The word rang out, startling Kent as well as Helen, and Mrs.
Brewster, whose noiseless entrance a few seconds before had gone
unobserved, hurried to them. "The envelope is mine."

CHAPTER XX. THE UNKNOWN EQUATION

"No, no," protested Helen vehemently. "You shall not give the envelope to
Margaret--you must not."

"It is mine," insisted the widow with equal vehemence.

"Mrs. Brewster." Kent withheld the envelope from both women. "Will you
tell me the contents of this envelope?"

"No," curtly. "It is not your affair."

"It is my affair," retorted Kent with equally shortness of manner. "I
insist on an answer to my questions in the limousine this morning. How
came your handkerchief in Jimmie's possession, and why did you go to the
police court and, yet keep your presence there a secret?"

"Jimmie must have picked up the handkerchief when in the McIntyre
house," she answered sullenly. "I presume he forgot to provide him self
with one in his make-up as burglar. As re