"Perhaps; I trust so."

"Then assist me to rid England of what you have called a survival of the dark ages. I will furnish porters to remove and carry the safe, if you will deliver to me the key!"

I sprang to my feet.

"That is madness!" I cried. "In the first place I should be compromising with my conscience, and in the second place I should be defenceless against those who might—"

"I have with me a written promise from one highly placed—one to whose will Hassan of Aleppo bows!"

My mind greatly disturbed, I watched the venerable speaker. I had determined now that he was some religious leader of Islam in England, who had been deputed to approach me; and, let me add, I was sorely tempted to accede to his proposal, for nothing would be gained by any one if the slipper remained for ever at the museum, whereas by conniving at its recovery by those who, after all, were its rightful owners I should be ridding England of a weird and undesirable visitant.

I think I should have agreed, when I remembered that the Hashishin had murdered Professor Deeping and had mutilated others wholly innocent of offence. I looked across at the old man. He had drawn himself up to his great height, and for the first time fully raising the lids, had fixed upon me the piercing gaze of a pair of eagle eyes. I started, for the aspect of this majestic figure was entirely different from that of the old stranger who had stood suppliant before me a moment ago.

"It is impossible," I said. "I can come to no terms with those who shield murderers."

He regarded me fixedly, but did not move.

"Es-selam 'aleykum!" I added ("Peace be on you!") closing the interview in the Eastern manner.

The old man lowered his eyes, and saluted me with graceful gravity.

"Wa-'aleykum!" he said ("And on you!"). I conducted him to the door and closed it upon his exit. In his last salute I had noticed the flashing of a ring which he wore upon his left hand, and he was gone scarce ten seconds ere my heart began to beat furiously. I snatched up "Assyrian Mythology" and with trembling fingers turned to a certain page.

There I read—

Each Sheikh of the Assassins is said to be invested with the "Ring of the Prophet." It bears a green stone, shaped in the form of a scimitar or crescent.

My dreadful suspicion was confirmed. I knew who my visitor had been.

"God in heaven!" I whispered. "It was Hassan of Aleppo!"

CHAPTER VII

FIRST ATTEMPT ON THE SAFE

On the following morning I was awakened by the arrival of Bristol. I hastened to admit him.

"Your visitor of yesterday," he began, "has wasted no time!"

"What has happened?"

He tugged irritably at his moustache. "I don't know!" he replied. "Of course it was no surprise to find that there isn't a Mohammedan who'll lay his little finger on Professor Deeping's safe! There's no doubt in my mind that every lascar at the docks knows Hassan of Aleppo to be in England. Some other arrangement will have to be arrived at, if the thing is ever to be taken to the Antiquarian Museum. Meanwhile we stand to lose it. Last night—"

He accepted a cigarette, and lighted it carefully.

"Last night," he resumed, "a member of P Division was on point duty outside the late Professor's house, and two C.I.D. men were actually in the room where the safe is. Result—someone has put in at least an hour's work on the lock, but it proved too tough a job!"

I stared at him amazedly.

"Someone has been at the lock!" I cried. "But that is impossible, with two men in the room—unless—"

"They were both knocked on the head!"

"Both! But by whom! My God! They are not—"

"Oh, no! It was done artistically. They both came round about four o'clock this morning."

"And who attacked them?"

"They had no idea. Neither of them saw a thing!"

My amazement grew by leaps and bounds. "But, Bristol, one of them must have seen the other succumb!"

"Both did! Their statements tally exactly!"

"I quite fail to follow you."

"That's not surprising. Listen: When I got on the scene about five o'clock, Marden and West, the two C.I.D. men, had quite recovered their senses, though they were badly shaken, and one had a cracked skull. The constable was conscious again, too."

"What! Was he attacked?"

"In exactly the same way! I'll give you Marden's story, as he gave it to me a few minutes after the surgeon had done with him. He said that they were sitting in the study, smoking, and with both windows wide open. It was a fearfully hot night."

"Did they have lights?"

"No. West sat in an armchair near the writing-table; Marden sat by the window next to the door. I had arranged that every hour one of them should go out to the gate and take the constable's report. It was just after Marden had been out at one o'clock that it happened.

"They were sitting as I tell you when Marden thought he heard a curious sort of noise from the gate. West appeared to have heard nothing; but I have no doubt that it was the sound of the constable's fall. West's pipe had gone out, and he struck a match to relight it. As he did so, Marden saw him drop the match, clench both fists, and with eyes glaring in the moonlight and his teeth coming together with a snap, drop from his chair.

"Marden says that he was half up from his seat when something struck him on the back of the head with fearful force. He remembered nothing more until he awoke, with the dawn creeping into the room, and heard West groaning somewhere beside him. They both had badly damaged skulls with great bruises behind the ear. It is instructive to note that their wounds corresponded almost to a fraction of an inch. They had been stunned by someone who thoroughly understood his business, and with some heavy, blunt weapon. A few minutes later came the man to relieve the constable; and the constable was found to have been treated in exactly the same way!"

"But if Marden's account is true—"

"West, as he lost consciousness, saw Marden go in exactly the same way."

"Marden was seated by the open window, but I cannot conjecture how any one can have got at West, who sat by the table!"

"The case of Marden is little less than remarkable; he was some distance from the window. No one could possibly have reached him from outside."

"And the constable?"

"The constable can give us no clue. He was suddenly struck down, as the others were. I examined the safe, of course, but didn't touch it, according to instructions. Someone had been at work on the lock, but it had defied their efforts. I'm fully expecting though that they'll be back to-night, with different tools!"

"The place is watched during the day, of course?"

"Of course. But it's unlikely that anything will be attempted in daylight. Tonight I am going down myself."

"Could you arrange that I join you?"

"I could, but you can see the danger for yourself?"

"It is extraordinarily mysterious."

"Mr. Cavanagh, it's uncanny!" said Bristol. "I can understand that one of these Hashishin could easily have got up behind the man on duty out in the open. I know, and so do you, that they're past masters of that kind of thing; but unless they possess the power to render themselves invisible, it's not evident how they can have got behind West whilst he sat at the table, with Marden actually watching him!"

"We must lay a trap for them to-night."

"Rely upon me to do so. My only fear is that they may anticipate it and change their tactics. Hassan of Aleppo apparently knows as much of our plans as we do ourselves."

Inspector Bristol, though a man of considerable culture, clearly was infected with a species of supernatural dread.