en we can't find the envelope," she muttered. "Hurry, Babs, and close
the outer door; father may return at any moment."

Barbara obeyed the injunction with such alacrity that the door,
concealing the space in the wall where stood the safe, flew to with a
bang and the twins jumped nervously.

"Take care!" exclaimed Helen sharply. "Do you wish to arouse the
household?"

"No danger of that." But Barbara glanced apprehensively about the
library in spite of her reassuring statement. "The servants are either
out or upstairs, and Margaret Brewster is writing letters in our sitting
room."

"Hadn't you better go upstairs and join her?" Helen suggested. "Do,
Babs," as her sister hesitated. "I cannot feel sure that she will not
interrupt us."

"But my joining her won't keep Margaret upstairs," objected Barbara.

"No, but you can call and warn me if she is on her way down, and that
will give me time to--to straighten father's papers," going over to
a large carved table littered with magazines, letters, and silver
ornaments. Her sister did not move, and she glanced at her with an
irritated air, very foreign to her customary manner. "Go, Barbara."

The curt command brought a stare from Barbara, but it did not accelerate
her halting footsteps; instead she moved with even greater slowness
toward the hall door; her active brain tormented with an unspoken and
unanswered question. Why was Helen so anxious for her departure? She had
accepted her offer of assistance in her search of the library with such
marked reluctance that Barbara had marveled at the time, and now...

"Are you quite sure, Helen, that father had the envelope in his pocket
this morning?" she asked for the third time since the search began.

"He had an envelope--I caught a glimpse of the red seal," answered
Helen. "Then, just before dinner he was putting some papers in the safe.
Oh, if Grimes had only come in a moment sooner to announce dinner, I
might have had a chance to look in the safe before father closed the
door."

Whatever reply Barbara intended making was checked by the rattling
of the knob of the hall door; it turned slowly, the door opened and,
pushing aside the portieres drawn across the entrance, Margaret Brewster
glided in. "So glad to find you," she cooed. "But why have you closed up
the room and turned on all the lights?"

"To see better," retorted Barbara promptly as the widow's eyes roved
around the large room, taking silent note of the drawn