which falls from it is relatively small and accumulates quite slowly, being practically confined to that which is pushed out of the holes by the movements of the insects within. This process would not account for the great quantity indicated by these samples of ours. My feeling was that this worm-eaten object was an appliance of some sort, subject to frequent and violent disturbance. Let us take an imaginary case as an illustration. Let us imagine a mallet with an excessively worm-eaten head. Whenever that mallet is used, the shock of the impact will send a shower of wood-dust flying out on the bench, where it will rapidly accumulate.
“But, of course, this object of ours could not be a mallet for the reason that mallets are always made of hard wood; and jewellers’ mallets are usually made of box-wood, lignum vitae or horn, none of which is subject to ‘the worm.’ Thinking over the various appliances used by jewellers—since it was with a jeweller we were dealing—I suddenly bethought me of one which seemed to fulfil the conditions exactly. Jewellers and goldsmiths, as you probably know, use a variety of miniature anvils, known as stakes, bec irons, sparrowhawks, etc. Now, these little anvils are usually stuck in a block of wood, just as a smith’s anvil is planted on a tree-stump. These blocks are not usually hard wood; indeed, soft wood is preferable as it absorbs the shock better. A favourite plan is to get a little log of wood and set the spike of the stake or sparrow-hawk in a hole bored in the end grain; and the most abundant source of these little logs—at least in the country—is the pile of trimmings from old fruit trees. Such a log would tend very soon to become worm-eaten; and if it did, every time it was used a ring of wood-dust would form around its base and would soon spread all over the bench, sticking to everything on it and straying on to the hands, arms, and clothing of the workman.
“This inference, you will observe, was, like the previous one, purely hypothetical. But it agreed perfectly with the observed facts and accounted for them in a reasonable way; and as I could think of no other that did, I adopted it with the necessary reservations. But, in fact, the correctness or incorrectness of this hypothesis was at present of no great importance. Apart from any question as to its exact origin, the wood-dust was an invaluable clue. We now knew that the unknown robber was a person whose clothing was more or less impregnated with wood-dust; that any places that he had frequented would yield traces of wood-dust from the floors, and that the place where the boxes had been packed abounded in wood-dust and contained a badly worm-eaten wooden object of some kind.
“The next proceeding was obvious. It was to find the places which had been frequented by that unknown person, to seek for the worm-eaten object, and, if possible, to identify the individual who appeared to be connected with it. The suspected places were two: Mr. Hollis’s house and Mr. Woodstock’s office. I did not, myself, suspect Hollis; but nevertheless I determined to examine his house as narrowly as the other. Accordingly I asked Mr. Penfield to obtain facilities for me to visit both places to make inquiries on the spot; which he did.
“Perhaps, before I describe that voyage of exploration, it may be as well to pause and consider what knowledge I now possessed and what I was going to look for. There was the wood-dust, of course. That was the visible trail that I hoped to pick up. But there were other matters. I knew that there was a man, in some way connected with the robbery, who had a short, fair moustache. I had to find out who he was. Also if there was any source from which some other person might collect specimen hairs from that moustache—a hair-brush, for instance—and if such source existed, who had access to it.
“Then there was the personality of the thief. One knew a good deal about him by this time. He was an ingenious man; a fairly good workman, at any rate, with metal-worker’s tools, but not a skilled jeweller. He must have been able to make a key from a wax squeeze—unless he were Woodstock himself, which he pretty certainly was not; for none of the others had sufficiently free access to the strong-room to do what had been done. Then he must have had at least a simple working knowledge of electric batteries, since we could be fairly certain that he made the electrotypes himself; he would never have run the risk of putting the forgery out to the trade. He was clearly a secretive, self-contained man. The only fallacy that I had to guard against was the possibility of a confederate outside the office, who might have done the actual work; but this possibility seemed to be negatived by the whole character of the robbery and especially by one very odd feature in it, which was this: Professor Eccles had noticed with surprise that many of the stones which were taken were of quite trifling intrinsic value, so trifling that, if they had been sold, they would hardly have realized enough to pay the cost of replacing them with the specially-made counterfeits. Indeed, in one case, at least, the thief must have lost money on the transaction, for he had taken a fine moonstone and replaced it with an inferior one of the same dimensions. But the value of the original was only about ten shillings, and he must have spent more than that on the replacement. The professor was greatly puzzled by this, having assumed, of course, that the gems were stolen to sell. But to me, this rather anomalous feature of the robbery offered a very curious suggestion; which was that no sale of the booty had ever been contemplated. It looked like a collector’s robbery; and if there had been a collector in any way connected with the parties, I should have given him my very close attention. But, so far as I knew, there was none. Nevertheless, this peculiarity of the robbery had to be borne in mind when I came to make my investigations on the spot.
“Let me now briefly describe those investigations. Their main object was to ascertain whether there were any traces of wood-dust in the premises of either Hollis or Woodstock, and the method was this: in each case, a rough ground-plan of the premises was made; then small areas of the floors were cleaned thoroughly with a specially constructed vacuum cleaner and the dust from each area put into an envelope marked with a number, which number was also marked in the plan on the spot from which the dust had been collected. The collection was carried out by my laboratory assistant, Mr. Polton, whom you have seen, leaving me free to make inquiries and to inspect the premises. Of course, the samples of dust had to be brought home to be examined in the laboratory, so we were hampered by the circumstance that we did not know at the time whether any wood-dust had or had not been obtained. But this proved to be of no importance.
“We operated first at Mr. Hollis’s house, regardless of his scornful protests. Then we went on to Mr. Woodstock’s office; and there I had a rather remarkable experiences As I entered with Mr. Woodstock, I saw an elderly man engaged in repairing an electric bell; and a glance at his hands and the way in which he manipulated his tools showed the unmistakable facility and handiness of the skilled workman. It was a little startling; for here were two of the characteristics of the unknown person I was endeavouring to identify. This man had evident skill in the use of metal-worker’s tools and he clearly knew a good deal about electric batteries. And when I learned that this Mr. Wampole was the office-keeper and that he evidently had a key of the premises, I was still further impressed. I began to revise my opinion as to there being no confederate; for the fact remained that Osmond had absconded and that his disappearance—until it was otherwise explained—undeniably connected him with the robbery. I began to think it possible that there had been a partnership and that he had been used as a cat’s paw. Meanwhile, I had to find out as much as I could about him, and to this end I sat down by Wampole, as he worked at refitting the batteries, and questioned him on the subject of Osmond’s appearance, habits, temperament, and circumstances. It is only fair to him to say that he scouted the idea of Osmond’s having committed the robbery and gave excellent reasons for rejecting it. On the other hand, his description of Osmond made it clear that the hairs which I had found in the boxes were Osmond’s hairs; and when I expressed a wish to inspect Osmond’s desk, he took me to it readily enough, and as it was unlocked, he threw up the lid and showed me the interior. The most interesting thing in it, from my point of view, was a pair of hair-brushes; from which I was able to extract several moustache hairs which appeared—and subsequently turned out to be—identically similar to those found in the boxes.
“The examination of Osmond’s desk suggested a similar examination of all the other desks in the office, finishing up with that belonging to Mr. Wampole. And it was in examining that desk that I did really receive somewhat of a shock. For when we came to turn out its contents, I found that these included, in addition to a number of metal-worker’s
