"Speaking candidly, I am not in a mood to discuss such visionary projects. I shall be glad if Mr. Forbes has gone to bed when I do ring him up."

Winter shook his head.

"Excuse me, Mr. Theydon, but I am older than you, and may 'venture on advice,'" he said. "A writer who has his way to make in the world cannot afford to slight a man of Mr. Forbes's standing. Go to him at once. It will please him. Don't hurry."

Theydon realized that a continued refusal would certainly set Furneaux's wits at work, and he dreaded the outcome. He went without another word.

When the outer door had closed behind him Winter turned to Furneaux.

"Well?" he said.

For answer Furneaux waved a hand and tiptoed into the hall. Waiting until he heard the door of No. 18 slam he opened the latch of No. 17 so cautiously that no sound was forthcoming. Soon he had an ear to Theydon's letter box and was following attentively a one-sided conversation.

Now, Theydon had thought hard during the few strides from one flat to the other. His telephone was fixed close to the party wall dividing the two sets of apartments and he was not certain that, in the absolute quietude prevailing in Innesmore Mansions at that late hour, a voice could not be overheard. True, he did not count on Furneaux playing the eavesdropper at the slit of the letter box, but he resolved to take no risks and say nothing that any one could make capital of.

So, when he had asked the exchange to reconnect him with the caller who had just rung up, and he was put through, this is what Furneaux heard:

"That you, Mr. Forbes. Sorry I sent my man just now with a message that must leave sounded rather curt, but the Scotland Yard people kindly excused me, so I can give you a minute or two.... No, I'm sorry, but I cannot come to luncheon tomorrow, nor go to Brooklands again this week.

You see, this dreadful murder which I spoke of will necessitate my presence at an inquest, and the police seem to attach much significance to the visit to Mrs. Lester last night of a man whom I saw in the street, and whom Bates and I heard entering and leaving the poor lady's flat.... Bates? O, he is my general factotum. He and his wife keep house for me.... Yes, I'll gladly let you know the earliest date when I'll be free. Then you and I can go into the flying proposition thoroughly....

No. The detectives have apparently not got any clew to the murderer, nor even discovered any motive for the crime. They have taken me into No.

17. In fact, I was there when your call was made.... The murderer ransacked the place thoroughly, but did not touch money or jewelry, I understand. The only peculiar thing, if I may so describe it, about the place, is the scent of a burnt joss stick. It clings to the passage and the bedroom in which the body was found.... Ah, by the way, Mrs. Lester wrote a letter, which her visitor posted, and the addressee, her aunt, is in communication with the police. The text tends to clear the man of suspicion.... Yes, if, by chance, I find myself at liberty tomorrow, I'll 'phone you at your city office. I'll find the number in the directory, of course?... O, thanks--I'll jot it down--00400 Bank....

Goodnight! Too bad that this wretched affair should interfere with our crusade, which, the more I think of it, the stronger it appeals. _Au revoir_, then."

In reality, Forbes had not said one word about his peace propaganda, but he had evidently been quick to realize that Theydon was purposely giving their talk a twist in that direction. A muttered "I understand--perfectly," showed this, and he did not strive to conceal the alarm which possessed him when Theydon spoke of the joss stick. He murmured distinctly, "Great Heavens! Then I was not mistaken," and again voiced his distress on hearing of the letter.

But he made matters easy by pressing Theydon to come and see him on the morrow, either at his office in Old Broad Street or at his residence. On the whole, Theydon did not care who heard what he had said, but it was a relief to find that he had to ring for readmission to No. 17.

Furneaux opened the door.

"You soon got rid of your friend, then?" said the detective, while they were on the way to rejoin Winter.

"Yes. It was just what I imagined--a pressing invitation to plunge forthwith into Mr. Forbes's project for the regeneration of mankind. I had to tell him frankly that you gentlemen had first claim on me. I suppose I shall be wanted at the inquest?"

"Not tomorrow. The coroner will hear the medical evidence, and that of Ann Rogers, if she is in a condition to appear, and there will be an adjournment for a week."

"Ah, that reminds me. Didn't Mrs. Lester's servant admit the visitor last night?"

Theydon put the question advisedly. He was calmer now, and had made up his mind as to the course he should pursue. Although he had assured Winter that he would recognize the stranger if confronted with him, and, if Forbes was brought into the inquiry, the admission might prove awkward, he meant to say that he had, indeed, noticed a remarkable resemblance in the millionaire to the man he had seen looking up at the name tablet on the corner, but felt that the likeness was only one of those singular coincidences which abound in a cosmopolitan city.

The smartest cross-examiner at the bar could not shake him if he took that stand. The sheer improbability of Forbes being the mysterious visitor would justify his attitude, and the notion was so consoling that he faced the two detectives with new confidence and a self-possession that was exceedingly pleasant when compared, with his earlier embarrassment.

"No," said Winter. "By a most remarkable chance, Ann Rogers was given leave to spend the night with her father, who lives in Camden Town. He is an old man and was taken ill last evening. He believes he asked some one to telegraph to his daughter, asking her to come to him. She certainly received a telegram and as certainly did visit him. Of course, that phase of the affair will be cleared up thoroughly, but the main facts are indisputable. Ann Rogers has her own latchkey. As Mrs. Lester usually sat up late, being a lover of books, and seldom stirred before ten o'clock, the maid waited until that hour before bringing her mistress's cup of tea. That stain on the carpet near the door shows where the tray fell from her hands."

Sometimes an artist obtains the strongest effect by one deft sweep of the brush. Winter, though he would have blushed if described as an artist in words, had achieved a similar result by his concluding sentence. Theydon pictured the scene. He saw the limp form thrown across the bed, the distorted face, the hands and arms posed grotesquely.

He heard the shrill scream of the terrified servant, an elderly woman whom Bates described as "a quiet body," and could imagine the clatter of the laden tray as it dropped from nerveless fingers. A sort of fury rose within him. Mrs. Lester had been done to death in a horrible and insensate way, and no matter who suffered, be he millionaire or pauper, the wretch who committed the crime should be made to pay the penalty of the law.

In that moment he forgot Evelyn Forbes, and thought only of the fair and gracious woman whose agonized spirit had taken flight under the compulsion of the tiger grip of some human brute now moving among his fellow-creatures unknown and unsuspected. It was inconceivable that Forbes should be guilty, but why should he not avow his acquaintance with the victim, and thus aid the police in their quest?

He glowered savagely at the telltale stain, and vowed to rid his conscience of an incubus. He would wait till the morrow and force Forbes to come out into the open. Otherwise--

"You wish you had the murderer here now?"

Furneaux spoke softly, and with no trace of his wonted irony, but Theydon was aware that once more the little detective had peered into his very soul.

"Yes," he said, and there was a new gravity in his tone. "I do wish that. I have never before been brought in contact with a crime of this magnitude. It conveys a sort of personal responsibility. To think that I was in my room, reading about aviation, while a woman's life was being choked out of her within a few feet of where I was seated! O, it is monstrous! Let me tell you two, here and now, that if I can do anything to bring Mrs. Lester's slayer to justice, you can count on me, no matter what the cost."

"I'm sure you mean what you say, Mr. Theydon," said Winter soothingly.

"Well, I suppose we can do no more tonight. I have little else to tell you--"

"The skull--the ivory skull!" put in Furneaux.

For an instant an expression of annoyance flitted across the chief inspector's good-humored face. Theydon did not see it, because Furneaux's odd-sounding words caused him to look with astonishment at the man who uttered them.

"An ivory skull!" he cried. "What has an ivory skull to do with the murder of Mrs. Lester?"

"We cannot even begin to guess at its meaning yet," said Winter, who, after one fierce glance at his colleague, had recovered his poise. "That is why I did not mention it. I hate the introduction of bizarre features into an inquiry of this sort. But, now that the thing has been spoken of, I may as well state that when the medical examination was being made at the mortuary a tiny skull, not bigger than a pea, and made of ivory, was found inside Mrs. Lester's underbodice. The curious fact is that it was loose. Had it been attached to a cord, or secured in some way, one might regard it as a charm or amulet, because some women, even in the London of today, are not beyond the reach of superstition in such matters. But, as I say, it was not safeguarded at all, so we may reasonably assume that it was not carried habitually. Of course, Furneaux readily evolved a far-fetched theory that it is a sign, or symbol, and was thrust out of sight among the clothing on the dead woman's breast by the man who killed her. But that is idle guesswork. We of the Yard seldom pay heed to theatrical notions of that kind. Here is the article. I don't mind letting you see it, but kindly remember that its existence must not be made known. I must have your promise not to mention it to a living creature."

Furneaux chuckled derisively.

"That is precisely the sort of thing anybody would say who attached no importance to the exhibit," he piped.

Winter so nearly lost his temper that he repressed the retort on his lips. He contented himself, however, with producing a small white object from his waistcoat pocket, and handed it to Theydon. It was a bit of ivory, hollow, and very light, and fashioned as a skull.

Yet, it was by no means an ordinary creation. The artist who fashioned it had gratified a morbid taste by imparting to the eyeless sockets and close-set rows of teeth a malign and threatening grin. Wickedness, not death, was suggested, but the craftsmanship was faultless. A collector would have paid a large sum for it, while the average citizen would refuse to have it in his house.

"What an extraordinary thing," said Theydon, turning the curio round and round in his fingers.

"It's wonderfully well carved," agreed Winter.

"From that point of view it's a masterpiece, but what I meant was the astounding fact that it should have been discovered on the dead woman's body. Was it placed over her heart?"

"Why do you ask that?" came the sharp demand.

"Because--if it is a token of some vendetta--if the murderer wished to signify that he had glutted his vengeance--"

"O, you're as bad as Furneaux," cried Winter impatiently. "Give it to me. I must be off. The hour is long past midnight and I have a busy day before me tomorrow."

Back in the seclusion of his own rooms, Theydon debated the question whether or not he should endeavor to communicate with Forbes again that night. Somehow it seemed to him that Forbes would be most concerned at hearing of the gray car. And what of the ivory skull?

Suppose he knew of that! But a certain revulsion of feeling had come over Theydon since the sheer brutality of the murder had been revealed.

He failed to see now why he should be so solicitous for Forbes's welfare. No matter what private purpose the man might serve by concealing his visit to Mrs. Lester, it ought to give way before the paramount importance of tracking a pitiless and callous criminal.

So Theydon hardened his heart and went to bed, and, being sound in mind and constitution, slept like a just man wearied. Nevertheless, the last thing he saw before the curtain fell on his tired brain was an ivory skull dancing in the darkness.

Greatly as the many problems attached to Mrs. Lester's death bewildered him, he would have been even more perplexed if he had overheard the conversation between Winter and Furneaux when they entered a taxi and gave Scotland Yard as their destination.

"Look here, Charles," began Winter firmly; but the other stayed him with a clutch of thin, nervous fingers on an arm strong enough to fell an ox.