He took from his assistant's hand a photograph ten inches long by eight broad, done on glazed bromide paper and mounted flatly on stiff card. It showed a greatly magnified facsimile of one of the thumb-prints, in which all the minute details, such as the orifices of the sweat glands and trifling irregularities in the ridges, which, in the original, could be seen only with the aid of a lens, were plainly visible to the naked eye. Moreover, the entire print was covered by a network of fine black lines, by which it was divided into a multitude of small squares, each square being distinguished by a number.
"Excellent, Polton," said Thorndyke approvingly; "a most admirable enlargement. You see, Jervis, we have photographed the thumb-print in contact with a numbered micrometer divided into square twelfths of an inch. The magnification is eight diameters, so that the squares are here each two-thirds of an inch in diameter. I have a number of these micrometers of different scales, and I find them invaluable in examining cheques, doubtful signatures and such like. I see you have packed up the camera and the microscope, Polton; have you put in the micrometer?"
"Yes, sir," replied Polton, "and the six-inch objective and the low-power eye-piece. Everything is in the case; and I have put 'special rapid' plates into the dark-slides in case the light should be bad."
"Then we will go forth and beard the Scotland Yard lions in their den," said Thorndyke, putting on his hat and gloves.
"But surely," said I, "you are not going to drag that great microscope to Scotland Yard, when you only want eight diameters. Haven't you a dissecting microscope or some other portable instrument?"
"We have a most delightful instrument of the dissecting type, of Polton's own makehe shall show it to you. But I may have need of a more powerful instrumentand here let me give you a word of warning: whatever you may see me do, make no comments before the officials. We are seeking information, not giving it, you understand."
At this moment the little brass knocker on the inner doorthe outer oak being openuttered a timid and apologetic rat-tat.
"Who the deuce can that be?" muttered Thorndyke, replacing the microscope on the table. He strode across to the door and opened it somewhat brusquely, but immediately whisked his hat off, and I then perceived a lady standing on the threshold.
"Dr. Thorndyke?" she inquired, and as my colleague bowed, she continued, "I ought to have written to ask for an appointment but the matter is rather urgentit concerns Mr. Reuben Hornby and I only learned from him this morning that he had consulted you."
"Pray come in," said Thorndyke. "Dr. Jervis and I were just setting out for Scotland Yard on this very business. Let me present you to my colleague, who is working up the case with me."
Our visitor, a tall handsome girl of twenty or thereabouts, returned my bow and remarked with perfect self-possession, "My name is GibsonMiss Juliet Gibson. My business is of a very simple character and need not detain you many minutes."
She seated herself in the chair that Thorndyke placed for her, and continued in a brisk and business-like manner
"I must tell you who I am in order to explain my visit to you. For the last six years I have lived with Mr. and Mrs. Hornby, although I am no relation to them. I first came to the house as a sort of companion to Mrs. Hornby, though, as I was only fifteen at the time, I need hardly say that my duties were not very onerous; in fact, I think Mrs. Hornby took me because I was an orphan without the proper means of getting a livelihood, and she had no children of her own.
"Three years ago I came into a little fortune which rendered me independent; but I had been so happy with my kind friends that I asked to be allowed to remain with them, and there I have been ever since in the position of an adopted daughter. Naturally, I have seen a great deal of their nephews, who spend a good part of their time at the house, and I need not tell you that the horrible charge against Reuben has fallen upon us like a thunderbolt. Now, what I have come to say to you is this: I do not believe that Reuben stole those diamonds. It is entirely out of character with all my previous experience of him. I am convinced that he is innocent, and I am prepared to back my opinion."
"In what way?" asked Thorndyke.
"By supplying the sinews of war," replied Miss Gibson. "I understand that legal advice and assistance involves considerable expense."
"I am afraid you are quite correctly informed," said Thorndyke.
"Well, Reuben's pecuniary resources are, I am sure, quite small, so it is necessary for his friends to support him, and I want you to promise me that nothing shall be left undone that might help to prove his innocence if I make myself responsible for any costs that he is unable to meet. I should prefer, of course, not to appear in the matter, if it could be avoided."
"Your friendship is of an eminently practical kind, Miss Gibson," said my colleague, with a smile. "As a matter of fact, the costs are no affair of mine. If the occasion arose for the exercise of your generosity you would have to approach Mr. Reuben's solicitor through the medium of your guardian, Mr. Hornby, and with the consent of the accused. But I do not suppose the occasion will arise, although I am very glad you called, as you may be able to give us valuable assistance in other ways. For example, you might answer one or two apparently impertinent questions."
"I should not consider any question impertinent that you considered necessary to ask," our visitor replied.
"Then," said Thorndyke, "I will venture to inquire if any special relations exist between you and Mr. Reuben."
"You look for the inevitable motive in a woman," said Miss Gibson, laughing and flushing a little. "No, there have been no tender passages between Reuben and me. We are merely old and intimate friends; in fact, there is what I may call a tendency in another directionWalter Hornby."
"Do you mean that you are engaged to Mr. Walter?"
"Oh, no," she replied; "but he has asked me to marry himhe has asked me, in fact, more than once; and I really believe that he has a sincere attachment to me."
She made this latter statement with an odd air, as though the thing asserted were curious and rather incredible, and the tone was evidently noticed by Thorndyke as well as me for he rejoined
"Of course he has. Why not?"
"Well, you see," replied Miss Gibson, "I have some six hundred a year of my own and should not be considered a bad match for a young man like Walter, who has neither property nor expectations, and one naturally takes that into account. But still, as I have said, I believe he is quite sincere in his professions and not merely attracted by my money."
"I do not find your opinion at all incredible," said Thorndyke, with a smile, "even if Mr. Walter were quite a mercenary young manwhich, I take it, he is not."
Miss Gibson flushed very prettily as she replied
"Oh, pray do not trouble to pay me compliments; I assure you I am by no means insensible of my merits. But with regard to Walter Hornby, I should be sorry to apply the term 'mercenary' to him, and yetwell, I have never met a young man who showed a stronger appreciation of the value of money. He means to succeed in life and I have no doubt he will."
"And do I understand that you refused him?"
"Yes. My feelings towards him are quite friendly, but not of such a nature as to allow me to contemplate marrying him."
"And now, to return for a moment to Mr. Reuben. You have known him for some years?"
"I have known him intimately for six years," replied Miss Gibson.
"And what sort of character do you give him?"