"If somnambulism, then who was the somnambulist?" The Thinking Machine resumed after a moment. "It did not seem to be you, Mrs. Roswell. You are not of a nervous temperament; you are a normal healthy woman. If we accept as true your statement that you were aroused in bed by the cockatoo screaming 'Jeanette' we prove that you were not the somnambulist. Your step-daughter? She suffered from a nervous disorder so pronounced that you had fears for her mental condition. With everyone else removed she was the somnambulist. Even the cockatoo said that.
"Now let us see how it would have been possible to open the vault. We admit that no one except yourself knew the combination. But a record of that combination did appear therefore it was possible for some one else to learn it. Your step-daughter does not know that combination when she is in a normal condition. I won't say that she knows it when in the sommambulistic state, but I will say that when in that condition she knows where there is a record of it. How she learned this I don't know. It is not a legitimate part of the problem.
"Be that as it may she was firmly convinced that something she was seeking, something of deep concern to her, was in that vault. It might not have been in the vault but in her abnormal condition she thought it was. She was not after jewels-her every act even tonight showed that. What else? Letters. I knew it was a letter, or letters, before she said so herself. What was in these letters is of no consequence here. You, Mrs. Roswell, considered it your duty to hide them-possibly destroy them."
Both husband and son turned on Mrs. Roswell inquiringly. She stared from one to the other helplessly, pleadingly.
"The letters contained--" she started to explain.
"Never mind that, it's none of our business," curtly interrupted The Thinking Machine. "If there is a family skeleton, it's yours."
"I won't believe anything against her," burst out Grantham passionately.
"Even with the practical certain knowledge that Miss Roswell did open the vault," The Thinking Machine resumed placidly, "and that she opened it in precisely the manner you saw tonight, I took one more step to prove it. This was after the second stone had disappeared. I instructed Mrs. Roswell to place a little strawberry jam on her step-daughter's hands while she was sleeping. If this jam appeared on the book the next time the vault was found open it proved finally and conclusively that Miss Roswell opened it. I chose strawberry jam because it was unusual. I dare say no one who might have a purpose in opening that vault would go around with strawberry jam on his hands. This jam did appear on the book, and then I summoned you, Dr. Forrester, and you, Dr. Henderson. You know the rest. I may add that Mr. Grantham in attempting to take the theft upon himself merely made a fool of himself. No person with bare fingers could have torn out one of the stones."
There was a long pause, and deep silence while the problem as seen by The Thinking Machine was considered in the minds of his hearers. Grantham at last broke the silence.
"Where are the two stones that are missing?"
"Oh yes," said The Thinking Machine easily, as if that trivial point had escaped him. "Mrs. Roswell, will you please have the cockatoo brought in?" he asked, and then explained to the others: "I had the bird removed from the room tonight for fear it would interrupt at the wrong moment."
Mrs. Roswell arose and gave some instructions to a servant who was waiting outside. He went away and returned later with a startled expression on his graven face.
"The bird is dead, madam," he reported.
"Dead?" repeated Mrs. Roswell.
"Good!" said The Thinking Machine rubbing his hands briskly together. "Bring it in anyhow."
"Why, what could have killed it?" asked Mrs. Roswell, bewildered.
"Indigestion," replied the scientist. "Here is the thief."
He turned suddenly to the servant who had entered bearing the cockatoo in state on a silver tray.
"Who? I?" gasped the astonished servant.
"No, this fellow," replied The Thinking Machine as he picked up the dead bird. "He had the opportunity; he had the pointed instrument necessary to pry out a stone-note the sharp hooked bill; and he had the strength to do it. Besides all that he confessed a fondness for bright things when he tried to snatch my eyeglasses. He saw Miss Roswell drop the tiara on the floor, its brightness fascinated him. He pried out the stone and swallowed it. It pained him, and he screamed 'Jeanette.' This same thing happened on two occasions. Your encyclopaedia will tell you that the cockatoo has more strength in that sharp beak than you could possibly exercise with two fingers unless you had a steel instrument."
Later that day The Thinking Machine sent to Mrs. Roswell the two missing diamonds, the glass head of a hat pin and a crystal shoe button which he had recovered from the dead bird. His diagnosis of the case was acute indigestion.
_________________________.
PROBLEM OF THE SOUVENIR CARDS.
There were three of the post cards. The first one was a vividly colored picture of the Capitol at Washington. It was postmarked, "Philadelphia, November 12, 2:30 p.m." Below the picture, in a small copperplate hand, were these figures and symbols: "I-28-38-4 x 47-30-2 x 21-19-8 x 65-5-3 x 29-32-11 x 40-2-9x."
The second post card was a picture of Park Square, Boston, with the majestic figures of Lincoln and the slave in the foreground. This, too, was postmarked Philadelphia, but the date was November 13. The symbols and figures were unquestionably written by the same hand as those on the first: "II-155-19-9 x 205-2-8 x agree x 228-31-2 x present tense x 235-13-4."
The third card was a colored reproduction of an idyllic bayou near New Orleans. Again the postmark was Philadelphia, but the date was November 14. This card contained only: "III-41-1-9 x 181-15-10 x press."
Professor Augustus S. F. X. Van Dusen-The Thinking Machine-turned and twisted the post cards in his slender fingers while he studied them through squinting, watery, blue eyes. At last he laid them on a table beside him, and sank back into his chair, with long white fingers pressed tip to tip. He was in a receptive mood.
"Well?" he demanded abruptly.
The bearded stranger who had offered the cards for his scrutiny was gazing at the diminutive figure and the drawn, petulant face of the scientist, seemingly in mingled wonder and amusement. It was difficult for him to associate this crabbed little man with those achievements which had placed his name so high in the sciences. After a moment the visitor's gaze wavered a little and dropped.
"My name is William C. Colgate," he began. "Sometime since-four weeks and three days, to be exact-a diamond was stolen from my house in this city, and no trace of it has ever been found. It was one I bought uncut in South Africa five years ago, and its weight is about thirty carats. When cut I imagine it will be eighteen to twenty carats, and it is, as it stands now, worth about forty thousand dollars. You may have read something of the theft in the newspapers?"
"I never read the newspapers," remarked The Thinking Machine.
"Well, in that event," and Colgate smiled, "I can briefly state the facts in the case. I have for several years had in my employment a secretary, Charles Travers. He is about twenty-five years old. Within the last four or five months I have noticed a change in his manner. Where formerly he had been quiet and unassuming, he has, through evil associations I dare say, grown to be a little wild, and, I believe, has lived beyond his income. I took occasion twice to remonstrate with him. The first time he seemed contrite and repentant; the second time he grew angry, and the following day disappeared. The diamond went with him."
"Do you know that?" demanded The Thinking Machine.
"I know it as well as one may know anything," replied Colgate positively. "I doubt if anyone except Travers knew where I kept the jewel. Certainly my servants did not, and certainly my wife and two daughters did not. Besides my wife and daughters have been in Europe for two months. The police seem to be unable to learn anything, so I came to you."
"Just where did you keep the jewel?"
"In a drawer of my desk," was the reply. "Ultimately I had intended to have it cut and present it to my oldest daughter, possibly on the occasion of her marriage. Now--" Colgate waved his hand.
The Thinking Machine sat silent for several minutes. His squint eyes were turned steadily upward and several tiny lines appeared in the domelike brow. "The problem then seems to be merely one of finding your secretary," he stated at last. "The diamond is of course so large that it would be absurd to attempt to dispose of it in its present shape. Travers is an intelligent man; we shall give him credit for realizing this. And yet if it should be cut up into smaller stones its value would dwindle to a tenth part of what it is now. Under those circumstances, would he have it cut up?"
"That is one of the questions which I should like to have answered."
For the second time The Thinking Machine picked up and examined the three post cards. "And what have these to do with it?" he demanded.
"That's another question I should like to have answered," said Colgate. "I can only believe that they in someway bear on the mystery surrounding the disappearance of the gem. Perhaps they give a clue to where it is now."
"This is Travers's handwriting?"
"Yes."
"The cards obviously constitute a cipher of some sort," explained the scientist. "Were you and Travers accustomed to communicating in cipher?"
"Not at all."
"Then why is this in cipher?" demanded The Thinking Machine belligerently. He glared at Colgate much as if he held him to blame.
Colgate shrugged his shoulders.
"Of course," continued the scientist, "I can find out what it means. It is elementary in character, and yet I doubt if, after we know what is in it, it will be particularly illuminating. Still, giving Travers credit for intelligence, I should imagine this to be an offer to return the diamond, probably for a consideration. But why in cipher?"
Colgate did not seem to be able to add to what he had already said, and after a few minutes took his leave, with instructions from The Thinking Machine to return on the following day, after the scientist had had an opportunity to study the post cards. He called at the appointed hour.