"But how did you manage to fix the date, Mr. Sage?" he enquired.

"By the previous outrages," was the reply.

"The previous outrages!" cried Sir John. "Dammit! how did they help you?"

"They all took place about the time the moon was at the full. There were twenty-eight in all." Malcolm Sage felt in his pocket and drew out a paper. "These are the figures."

In his eagerness Sir John s.n.a.t.c.hed the paper from his hand, and with Inspector Wensdale looking over his shoulder, read:

Day before full moon . . . . 4 Full moon . . . . . . 15 Day after . . . . . . 7 Second day after . . . . . 2 -- Total 28 . . . . . . 28

"Well, I'm d.a.m.ned!" exclaimed Sir John, looking up from the paper at Malcolm Sage, as if he had solved the riddle of the universe.

The inspector's only comment was a quick indrawing of breath.

Sir John continued to stare at Malcolm Sage, the paper still held in his hand.

"That made matters comparatively easy," continued Malcolm Sage. "The outrages were clearly not acts of revenge upon any particular person; for they involved nine different owners. They were obviously the work of someone subject to a mania, or obsession, which gripped him when the moon was at the full."

"But how did you fix the actual spot?" burst out Inspector Wensdale excitedly.

"Each of the previous acts had been either in a diametrically opposite direction from that immediately preceding it, or practically on the same spot. For instance, the first three were north, east, and south of Hempdon, in the order named. Then the cunning of the perpetrator prompted him to commit a fourth, not to the west; but to the south, within a few yards of the previous act.

The criminal argued, probably subconsciously, that he would be expected to complete the square."

"But what made you fix on Hempdon as the headquarters of the blackguard?" enquired Sir John.

"That was easy," remarked Malcolm Sage, polishing the thumb-nail of his left hand upon the palm of his right.

"Easy!" The exclamation burst involuntarily from the inspector.

"You supplied me with a large scale-map showing the exact spot where each of the previous maimings had taken place. I drew a square to embrace the whole. Lines drawn diagonally from corner to corner gave me the centre of gravity."

"But----" began the inspector.

Ignoring the interruption Malcolm Sage continued.

"A man committing a series of crimes from a given spot was bound to spread his operations over a fairly wide area in order to minimise the chance of discovery. The longer the period and the larger the number of comes, the greater the chance of his being located somewhere near the centre of his activities."

"Well, I'm d.a.m.ned!" remarked Sir John for the second time. Then suddenly turning to Inspector Wensdale, "Dammit!" he exploded, "why didn't you think of that?"

"There was, of course, the chance of his striking in another direction," continued Malcolm Sage, digging into the bowl of his pipe with a penknife, "so I placed the men in such a way that if he did so he was bound to be seen."

Inspector Wensdale continued to gaze at him, eager to hear more.

"But what was that you said about race-memory?" Sir John had quieted down considerably since Malcolm Sage had begun his explanation.

"I should describe it as a harking back to an earlier phase. It is to the mind what atavism is to the body. In breeding, for instance"--Malcolm Sage looked across to Sir John--"you find that an offspring will manifest characteristics, or a taint, that is not to be found in either sire or dam."

Sir John nodded.

"Well, race-memory is the same thing in regard to the mental plane, a sort of subconscious wave of reminiscence. In Callice's case it was in all probability the memory of some sacrificial rite of his ancestors centuries ago."

"A case of heredity."

"Broadly speaking, yes. At the full moon this particular tribe, whose act Callice has reproduced, was in the habit of slaughtering some beast, or beasts, and drinking the blood, probably with the idea of absorbing their strength or their courage. Possibly the surroundings at Hempdon were similar to those where the act of sacrifice was committed in the past.

"It must be remembered that Callice was an ascetic, and consequently highly subjective. Therefore when the wave of reminiscence is taken in conjunction with the surroundings, the full moon and his high state of subjectivity, it is easy to see that material considerations might easily be obliterated. That is why I watched the back entrance to his lodgings."

"And all the time we were telling him our plans," murmured the inspector half to himself.

"Yes, and he would go out hunting himself," said Sir John. "d.a.m.n funny, I call it. Anyway, he'll get seven years at least."

"When he awakens he will remember nothing about it. You cannot punish a man for a subconscious crime."

Sir John snorted indignantly; but Inspector Wensdale nodded his head slowly and regretfully.

"Anyway, I owe you five hundred pounds," said Sir John to Malcolm Sage; "and, dammit! it's worth it," he added.

Malcolm Sage shrugged his shoulders as he rose to go.

"I was sorry to have to hit him," he said regretfully, "but I was afraid of that knife. A man can do a lot of damage with a thing like that. That's why I told you not to let your men attempt to take him, Wensdale."

"How did you know what sort of knife it was?" asked the inspector.

"Oh! I motored down here, and the car broke down. Incidentally I made a lot of acquaintances, including Callice's patrol-leader, a bright lad. He told me a lot of things about Callice and his ways. A remarkable product the boy scout," he added. "Kipling calls him 'the friend of all the world.'"

Sir John looked across at Inspector Wensdale, who was strongly tempted to wink.

"Don't think too harshly of Callice," said Malcolm Sage as he shook hands with Sir John. "It might easily have been you or I, had we been a little purer in mind and thought."

And with that he pa.s.sed out of the room with Inspector Wensdale followed by Sir John Hackblock, who was endeavouring to interpret the exact meaning of the remark.

"They said he was a clever devil," he muttered as he returned to the library after seeing his guests off, "and, dammit! they were right."

CHAPTER VI THE STOLEN ADMIRALTY MEMORANDUM

I

"Well," cried Tims, one Sat.u.r.day night, as he pushed open the kitchen door of the little flat he occupied over the garage. "How's the cook, the stove, and the supper?"

"I'm busy," said Mrs. Tims, a little, fair woman, with blue eyes, an impertinent nose, and the inspiration of neatness in her dress, as she altered the position of a saucepan on the stove and put two plates into the oven to warm.