“You didn’t put it quite in that way, my dear,” said Mrs. Hornby, “but I suppose it doesn’t matter.”
“We are highly gratified by Miss Gibson’s favourable report of us, whatever may have been the actual form of expression,” said Thorndyke, with a momentary glance at the younger lady which covered her with smiling confusion, “and we are deeply indebted to you for taking so much trouble to help us.”
“It is no trouble at all, but a great pleasure,” replied Mrs. Hornby; and she proceeded to enlarge on the matter until her remarks threatened, like the rippling circles produced by a falling stone, to spread out into infinity. In the midst of this discourse Thorndyke placed chairs for the two ladies, and, leaning against the mantelpiece, fixed a stony gaze upon the small handbag that hung from Mrs. Hornby’s wrist.
“Is the ‘Thumbograph’ in your bag?” interrupted Miss Gibson, in response to this mute appeal.
“Of course it is, my dear Juliet,” replied the elder lady. “You saw me put it in yourself. What an odd girl you are. Did you think I should have taken it out and put it somewhere else? Not that these handbags are really very secure, you know, although I daresay they are safer than pockets, especially now that it is the fashion to have the pocket at the back. Still, I have often thought how easy it would be for a thief or a pickpocket or some other dreadful creature of that kind, don’t you know, to make a snatch and—in fact, the thing has actually happened. Why, I knew a lady—Mrs. Moggridge, you know, Juliet—no, it wasn’t Mrs. Moggridge, that was another affair, it was Mrs.—Mrs.—dear me, how silly of me!—now, what was her name? Can’t you help me, Juliet? You must surely remember the woman. She used to visit a good deal at the Hawley-Johnsons’—I think it was the Hawley-Johnsons’, or else it was those people, you know—”
“Hadn’t you better give Dr. Thorndyke the ‘Thumbograph’?” interrupted Miss Gibson.
“Why, of course, Juliet, dear. What else did we come here for?” With a slightly injured expression, Mrs. Hornby opened the little bag and commenced, with the utmost deliberation, to turn out its contents on to the table. These included a laced handkerchief, a purse, a card-case, a visiting list, a packet of papier poudré, and when she had laid the last-mentioned article on the table, she paused abruptly and gazed into Miss Gibson’s face with the air of one who has made a startling discovery.
“I remember the woman’s name,” she said in an impressive voice. “It was Gudge—Mrs. Gudge, the sister-in-law of—”
Here Miss Gibson made an unceremonious dive into the open bag and fished out a tiny parcel wrapped in notepaper and secured with a silk thread.
“Thank you,” said Thorndyke, taking it from her hand just as Mrs. Hornby was reaching out to intercept it. He cut the thread and drew from its wrappings a little book bound in red cloth, with the word “Thumbograph” stamped upon the cover, and was beginning to inspect it when Mrs. Hornby rose and stood beside him.
“That,” said she, as she opened the book at the first page, “is the thumb-mark of a Miss Colley. She is no connection of ours. You see it is a little smeared—she said Reuben jogged her elbow, but I don’t think he did; at any rate he assured me he did not, and, you know—”
“Ah! Here is one we are looking for,” interrupted Thorndyke, who had been turning the leaves of the book regardless of Mrs. Hornby’s rambling comments; “a very good impression, too, considering the rather rough method of producing it.”
He reached out for the reading lens that hung from its nail above the mantelpiece, and I could tell by the eagerness with which he peered through it at the thumb-print that he was looking for something. A moment later I felt sure that he had found that something which he had sought, for, though he replaced the lens upon its nail with a quiet and composed air and made no remark, there was a sparkle of the eye and a scarcely perceptible flush of suppressed excitement and triumph which I had begun to recognise beneath the impassive mask that he presented to the world.
“I shall ask you to leave this little book with me, Mrs. Hornby,” he said, breaking in upon that lady’s inconsequent babblings, “and, as I may possibly put it in evidence, it would be a wise precaution for you and Miss Gibson to sign your names—as small as possible—on the page which bears Mr. Reuben’s thumb-mark. That will anticipate any suggestion that the book has been tampered with after leaving your hands.”
“It would be a great impertinence for anyone to make any such suggestion,” Mrs. Hornby began; but on Thorndyke’s placing his fountain pen in her hand, she wrote her signature in the place indicated and handed the pen to Miss Gibson, who signed underneath.
“And now,” said Thorndyke, “we will take an enlarged photograph of this page with the thumb-mark; not that it is necessary that it should be done now, as you are leaving the book in my possession; but the photograph will be wanted, and as my man is expecting us and has the apparatus ready, we may as well despatch the business at once.”
To this both the ladies readily agreed (being, in fact, devoured by curiosity with regard to my colleague’s premises), and we accordingly proceeded to invade the set of rooms on the floor above, over which the ingenious Polton was accustomed to reign in solitary grandeur.
It was my first visit to these mysterious regions, and I looked about me with as much curiosity as did the two ladies. The first room that we entered was apparently the workshop, for it contained a small woodworker’s bench, a lathe, a bench for metal work and a number of mechanical appliances which I was not then able to examine; but I noticed that the entire place presented to the eye a most unworkmanlike neatness, a circumstance that did not escape Thorndyke’s observation, for his face relaxed into a grim smile as his eye travelled over the bare benches and the clean-swept floor.
From this room we entered the laboratory, a large apartment, one side of which was given up to chemical research, as was shown by the shelves of reagents that covered the wall, and the flasks, retorts and other apparatus that were arranged on the bench, like ornaments on a drawing-room mantelpiece. On the opposite side of the room was a large, massively-constructed copying camera, the front of which, carrying the lens, was fixed, and an easel or copyholder travelled on parallel guides towards, or away, from it, on a long stand.
This apparatus Thorndyke proceeded to explain to our visitors while Polton was fixing the “Thumbograph” in a holder attached to the easel.
“You see,” he said, in answer to a question from Miss Gibson, “I have a good deal to do with signatures, cheques and disputed documents of various kinds. Now a skilled eye, aided by a pocket-lens, can make out very minute details on a cheque or bank-note; but it is not possible to lend one’s skilled eye to a judge or juryman, so that it is often very convenient to be able to hand them a photograph in which the magnification is already done, which they can compare with the original. Small things, when magnified, develop quite unexpected characters; for instance, you have handled a good many postage stamps, I suppose, but have you ever noticed the little white spots in the upper corner of a penny stamp, or even the difference in the foliage on the two sides of the wreath?”
Miss Gibson admitted that she had not.
“Very few people have, I suppose, excepting stamp-collectors,” continued Thorndyke; “but now just glance at this and you will find these unnoticed details forced upon your attention.” As he spoke, he handed her a photograph, which he had taken from a drawer, showing a penny stamp enlarged to a length of eight inches.
While the ladies were marvelling over this production, Polton proceeded with his work. The “Thumbograph” having been fixed in position, the light from a powerful incandescent gas lamp, fitted with a parabolic reflector, was concentrated on it, and the camera racked out to its proper distance.
“What are those figures intended to show?” inquired Miss Gibson, indicating the graduation on the side of one of the guides.
“They show the amount of magnification or reduction,” Thorndyke explained. “When the pointer is opposite 0, the photograph is the same size as the object photographed; when it points