the day that followed was one of the hottest which we experienced during the heat wave. it was a day crowded with happenings. the burton room was closed to the public, whilst a glazier worked upon the broken east window and a new blind was fitted to the west. behind the workmen, guarded by a watchful commissionaire, yawned the shattered case containing the slipper.

i wondered if the visitors to the other rooms of the museum realized, as i realized, that despite the blazing sunlight of tropical london, the shadow of hassan of aleppo lay starkly on that haunted building?

at about eleven o'clock, as i hurried along the strand, i almost collided with the girl of the violet eyes! she turned and ran like the wind down arundel street, whilst i stood at the corner staring after her in blank amazement, as did other passers-by; for a man cannot with dignity race headlong after a pretty woman down a public thoroughfare!

my mystification grew hourly deeper; and bristol wallowed in perplexities.

"it's the most horrible and confusing case," he said to me when i joined him at the museum, "that the yard has ever had to handle. it bristles with outrages and murders. god knows where it will all end. i've had london scoured for a clue to the whereabouts of hassan and company and drawn absolutely blank! then there's earl dexter. where does he come in? for once in a way he's living in hiding. i can't find his headquarters. i've been thinking—"

he drew me aside into the small gallery which runs parallel with the assyrian room.

"dexter has booked two passages in the oceanic. who is his companion?"

i wondered, i had wondered more than once, if his companion were my beautiful violet-eyed acquaintance. a scruple—perhaps an absurd scruple—hitherto had kept me silent respecting her, but now i determined to take bristol fully into my confidence. a conviction was growing upon me that she and earl dexter together represented that third party whose existence we had long suspected. whether they operated separately or on behalf of the moslems (of which arrangement i could not conceive) remained to be seen. i was about to voice my doubts and suspicions when bristol went on hurriedly—

"i have thoroughly examined the burton room, and considering that the windows are thirty feet from the ground, that there is no sign of a ladder having stood upon the lawn, and that the iron bars are quite intact, it doesn't look humanly possible for any one to have been in the room last night prior to mostyn's arrival!"

"one of the dwarfs—"

"not even one of the dwarfs," said bristol, "could have passed between those iron bars!"

"but there was blood on the window!"

"i know there was, and human blood. it's been examined!"

he stared at me fixedly. the thing was unspeakably uncanny.

"to-night," he went on, "i am remaining in here"—nodding toward the assyrian room—"and i have so arranged it that no mortal being can possibly know i am here. mostyn is staying, and you can stay, too, if you care to. owing to professor deeping's will you are badly involved in the beastly business, and i have no doubt you are keen to see it through."

"i am," i admitted, "and the end i look for and hope for is the recovery of the slipper by its murderous owners!"

"i am with you," said bristol. "it's just a point of honour; but i should be glad to make them a present of it. we're ostentatiously placing a constable on duty in the hallway to-night—largely as a blind. it will appear that we're taking no other additional precautions."

he hurried off to make arrangements for my joining him in his watch, and thus again i lost my opportunity of confiding in him regarding the mysterious girl.

i half anticipated, though i cannot imagine why, that earl dexter would put in an appearance, during the day. he did not do so, however, for bristol had put a constable on the door who was well acquainted with the appearance of the stetson man. the inspector, in the course of his investigations, had come upon what might have been a clue, but what was at best a confusing one. close by the wall of the curator's house and lying on the gravel path he had found a part of a gold cuff link. it was of american manufacture.

upon such slender evidence we could not justly assume that it pointed to the presence of dexter on the night of the attempted robbery, but it served to complicate a matter already sufficiently involved.

in pursuance of bristol's plan, i concealed myself that evening just before the closing of the museum doors, in a recess behind a heavy piece of babylonian sculpture. bristol was similarly concealed in another part of the room, and mostyn joined us later.

the museum was closed; and so far as evidence went the authorities had relied again upon the bolts and bars hitherto considered impregnable, and upon the constable in the hall. the broken window was mended, the cut blind replaced, and within, in its shattered case, reposed the slipper of the prophet.

all the blinds being lowered, the assyrian room was a place of gloom, yellowed on the western side by the moonlight through the blind. the door communicating with the burton room was closed but not fastened.

"they operated last night," bristol whispered to me, "at the exact time when the moonlight shone through the hole in the westerly blind on to the case. if they come to-night, and i am quite expecting them, they will have to dispense with that assistance; but they know by experience where to reach the case."

"despite our precautions," i said, "they will almost certainly know that a watch is being kept."

"they may or they may not," replied bristol. "either way i'm disposed to think there will be another attempt. their mysterious method is so rapid that they can afford to take chances."

this was not my first night vigil since i had become in a sense the custodian of the relic, but it was quite the most dreary. amid the tomb-like objects about us we seemed two puny mortals toying with stupendous things. we could not smoke and must converse only in whispers; and so the night wore on until i began to think that our watch would be dully uneventful.

"our big chance," whispered mostyn, "is in the fact that any day may change the conditions. they can't afford to wait."

he ceased abruptly, grasping my arm. from somewhere, somewhere outside the building, we all three had heard a soft whistle. a moment of tense listening followed.

"if only we could have had the place surrounded," whispered bristol—"but it was impossible, of course."

a faint grating noise echoed through the lofty burton room. bristol slipped past me in the semi-gloom, and gently opened the communicating door a few inches.

a-tiptoe, i joined him, and craning across his shoulder saw a strange and wonderful thing.

the newly glazed east window again was shattered with a booming crash! the yellow blind was thrust aside. a long something reached out toward the broken case. there was a sort of fumbling sound, and paralyzed with the wonder of it—for the window, remember, was thirty feet from the ground—i stood frozen to my post.

not so bristol. as the weird tentacle (or more exactly it reminded me of a gigantic crab's claw) touched the case, the inspector leapt forward. a white beam from his electric torch cut through to the broken cabinet.

the thing was withdrawn ... and with it went the slipper of the prophet.

"raise the blinds!" cried bristol. "mr. cavanagh! mr. mostyn! we must not let them give us the slip!"

i got up the blind of the nearer window as bristol raised the other. not a living thing was in sight from either!

mostyn was beside me, his hand resting on my shoulder. i noted how he trembled. bristol turned and looked back at us. the light from his pocket torch flashed upon the curator's face; and i have never seen such an expression of horrified amazement as that which it wore. faintly, i could hear the constable racing up the steps from the hall.

ideas of the supernatural came to us all, i know; when, with a scuffling sound not unlike that of a rat in a ceiling, something moved above us!

"damn my thick head!" roared bristol, furiously. "he's on the roof! it's flat as a floor and there's enough ivy alongside the water-spout on your house adjoining, mr. mostyn, to afford foothold to an invading army!"

he plunged off toward the open door, and i heard him racing down the assyrian room.

"he had a short rope ladder fixed from the gutter!" he cried back at us. "graham! graham!" (the constable on duty in the hall)—"get the front door open! get..." his voice died away as he leapt down the stairs.

from the direction of orpington square came a horrid, choking scream. it rose hideously; it fell, rose again—and died.

the thief escaped. we saw the traces upon the ivy where he had hastened down. bristol ascended by the same route, and found where the ladder-hooks had twice been attached to the gutterway. constable graham, who was first actually to leave the building, declared that he heard the whirr of a re-started motor lower down great orchard street.

bristol's theory, later to be dreadfully substantiated, was that the thief had broken the glass and reached into the case with an arrangement similar to that employed for pruning trees, having a clutch at the end, worked with a cord.

"hassan has been too clever for us!" said the inspector. "but—what in god's name did that awful screaming mean?"

i had a theory, but i did not advance it then.

it was not until nearly dawn that my theory, and bristol's, regarding the clutch arrangement, both were confirmed. for close under the railings which abut on orpington square, in a pool of blood we found just such an instrument as bristol had described.

and still clutching it was a pallid and ghastly shrunken hand that had been severed from above the wrist!

"merciful god!" whispered the inspector—"look at the opal ring on the finger! look at the bandage where he cut himself on the broken window-glass that first night, when mr. mostyn disturbed him. it wasn't the hashishin who stole the thing.... it's earl dexter's hand!"

no one spoke for a moment. then—

"which of them has—" began mostyn huskily.

"the slipper of the prophet?" interrupted bristol. "i wonder if we shall ever know?"