to the vehicle--which moved away at
accelerated speed, swung around the next corner and was gone.

Stuart ran forward and picked up the note. Without pausing to read it,
he pressed on to the corner. The cab was already two hundred yards
away, and he recognized pursuit to be out of the question. The streets
were almost deserted at the moment, and no one apparently had
witnessed the episode. He unfolded the sheet of plain note-paper,
faintly perfumed with jasmine, and read the following, written in an
uneven feminine hand:

"Close your shutters at night. Do not think too bad of me."

CHAPTER XI

THE BLUE RAY

Dusk found Stuart in a singular frame of mind. He was torn between
duty--or what he conceived to be his duty--to the community, and ...
something else. A messenger from New Scotland Yard had brought him a
bundle of documents relating to the case of Sir Frank Narcombe, and
a smaller packet touching upon the sudden end of Henrik Ericksen, the
Norwegian electrician, and the equally unexpected death of the Grand
Duke Ivan. There were medical certificates, proceedings of coroners,
reports of detectives, evidence of specialists and statements of
friends, relatives and servants of the deceased. A proper examination
of all the documents represented many hours of close study.

Stuart was flattered by the opinion held of his ability by the
Assistant Commissioner, but dubious of his chance of detecting any
flaw in the evidence which had escaped the scrutiny of so many highly
trained observers.

He paced the study restlessly. Although more than six hours had
elapsed, he had not communicated to Scotland Yard the fact of his
having seen Mlle. Dorian that afternoon. A hundred times he had read
the message, although he knew it by heart, knew the form of every
letter, the odd crossing of the _t'_s and the splashy dotting of
the _i_'s.

If only he could have taken counsel with someone--with someone not
bound to act upon such information--it would have relieved his mental
stress. His ideas were so chaotic that he felt himself to be incapable
of approaching the task presented by the pile of papers lying upon his
table.

The night was pleasantly warm and the sky cloudless. Often enough he
found himself glancing toward the opened French windows, and once he
had peered closely across into the belt of shadow below the hedge,
thinking that he had detected something which moved there. Stepping
to the window, the slinking