s a rail around the case,
to prevent visitors from touching even the glass."

"Ah," said Dr. Nicholson quizzically, "And has anything untoward
happened to our Graeco-Moslem friend?"

"Perhaps Inspector Bristol can tell," replied the curator.

The straight, military figure of the well-known Scotland Yard man
was conspicuous among the group of distinguished--and mostly
round-shouldered--scholars.

"Sorry, gentlemen," he said, smiling, "but Mr. Acepulos has vanished
from his tobacco shop in Soho. I am not apprehensive that he had
been kidnapped or anything of that kind. I think rather that the
date of his disappearance tallies with that on which he cashed his
cheque for service rendered! His present wife is getting most
unbeautifully fat, too."

"What precautions," someone asked, "are being taken to guard the
slipper?"

"Well," Mostyn answered, "though we have only the bare word of the
late Professor Deeping that the slipper was actually worn by
Mohammed, it has certainly an enormous value according to Moslem
ideas. There can be no doubt that a group of fanatics known as
Hashishin are in London engaged in an extraordinary endeavour to
recover it."

Mostyn's voice sank to an impressive whisper. My gaze sought again
the tall Eastern visitor and was held fascinated by the baffled
straining in those velvet eyes. But the lids fell as I looked; and
the effect was that of a fire suddenly extinguished. I determined
to draw Bristol's attention to the man.

"Accordingly," Mostyn continued, "we have placed it in this room,
from which I fancy it would puzzle the most accomplished thief to
remove it."

The party, myself included, stared about the place, as he went on
to explain--

"We have four large windows here; as you see. The Burton Room
occupies the end of a wing; there is only one door; it communicates
with the next room, which in turn opens into the main building by
another door on the landing. We are on the first floor; these two
east windows afford a view of the lawn before the main entrance;
those two west ones face Orpington Square; all are heavily barred
as you see. During the day there is a man always on duty in these
two rooms. At night that communicating door is locked. Short of
erecting a ladder in full view either of the Square or of Great
Orchard Street, filing through four iron bars and breaking the
window and the case, I fail to see how anybody can get at the
slipper here."

"If a dupli