While she was waiting it occurred to her that perhaps it might serve her purpose.

She got the instrument out.

It consisted of a little arrangement that fitted over the forearm, and was attached by a tube to a dial that registered in millimeters a column of mercury.

Would it really show anything, she wondered?
There was a quick call on the telephone and she answered it, her hand trembling, for she felt sure that it was something about the little woman she had befriended.
Somehow or other her voice hardened as she answered the call and found that it was from Drummond.

It would never do to betray even nervousness before him.
"Your friend, Miss Carr," shot out Drummond with brutal directness, "has been caught again.