The doctor, who was easily the most musical of the four men, sang in a cheerful baritone: "The owl and the pussy-cat went to sea In a beautiful, pea-green boat."

The doctor closed the door behind him, crossed to the table, silently offered the geologist a cigar, and waited until smoke was issuing from it.

"Remember, now; don't make a sound, no matter what you see!" Mrs. Kinney eyed her caller anxiously as they came to a pause in front of the door. His glance widened at her caution, but he nodded briefly. She turned the key in the lock.