in the hole at the apex of the conical end, was now seen to be the pointed termination of a slender steel rod which projected fully an inch into the cavity of the cylinder, and the conical end itself was a solid mass of lead.
"Well?" queried Thorndyke, seeing that I was still silent.
"You tell me it is not an explosive bullet," I replied, "otherwise I should have been confirmed in that opinion. I should have said that the percussion cap was carried by this lead plunger and struck on the end of that steel rod when the flight of the bullet was suddenly arrested."
"Very good indeed," said Thorndyke. "You are right so far that this is, in fact, the mechanism of a percussion shell.
"But look at this. You see this little rod was driven inside the bullet when the latter struck the wall. Let us replace it in its original position."
He laid the end of a small flat file against the end of the rod and pressed it firmly, when the rod slid through the hole until it projected an inch beyond the apex of the cone. Then he handed the projectile back to me.
A single glance at the point of the steel rod made the whole thing clear, and I gave a whistle of consternation; for the "rod" was a fine tube with a sharply pointed end.
"The infernal scoundrel!" I exclaimed; "it is a hypodermic needle."
"Yes. A veterinary hypodermic, of extra large bore. Now you see the subtlety and ingenuity of the whole thing. If he had had a reasonable chance he would certainly have succeeded."
"You speak quite regretfully," I said, laughing again at the oddity of his attitude towards the assassin.
"Not at all," he replied. "I have the character of a single-handed player, but even the most self-reliant man can hardly make a post-mortem on himself. I am merely appreciating an admirable piece of mechanical design most efficiently carried out. Observe the completeness of the thing, and the way in which all the necessities of the case are foreseen and met. This projectile was discharged from a powerful air-gun—the walking-stick form—provided with a force-pump and key. The barrel of that gun was rifled."
"How do you know that?" I asked.
"Well, to begin with, it would be useless to fit a needle to the projectile unless the latter was made to travel with the point forwards; but there is direct evidence that the barrel was rifled. You notice the little square projection on the back surface of the cylinder. That was evidently made to fit a washer or wad—probably a thin plate of soft metal which would be driven by the pressure from behind into the grooves of the rifling and thus give a spinning motion to the bullet. When the latter left the barrel, the wad would drop off, leaving it free."
"I see. I was wondering what the square projection was for. It is, as you say, extremely ingenious."
"Highly ingenious," said Thorndyke, enthusiastically, "and so is the whole device. See how perfectly it would have worked but for a mere fluke and for the complication of your presence. Supposing that I had been alone, so that he could have approached to a shorter distance. In that case he would not have missed, and the thing would have been done. You see how it was intended to be done, I suppose?"
"I think so," I answered; "but I should like to hear your account of the process."
"Well, you see, he first finds out that I am returning by a late train—which he seems to have done—and he waits for me at the terminus. Meanwhile he fills the cylinder with a solution of a powerful alkaloidal poison, which is easily done by dipping the needle into the liquid and sucking at the small hole near the back end, when the piston will be drawn up and the liquid will follow it. You notice that the upper side of the piston is covered with vaseline—introduced through the hole, no doubt—which would prevent the poison from coming out into the mouth, and make the cylinder secure from leakage. On my arrival, he follows me on his bicycle until I pass through a sufficiently secluded neighbourhood. Then he approaches me, or passes me and waits round a corner, and shoots at pretty close range. It doesn't matter where he hits me; all parts are equally vital, so he can aim at the middle of my back. Then the bullet comes spinning through the air point foremost; the needle passes through the clothing and enters the flesh, and, as the bullet is suddenly stopped, the heavy piston flies down by its own great momentum and squirts out a jet of the poison into the tissues. The bullet then disengages itself and drops on to the ground.
"Meanwhile, our friend has mounted his bicycle and is off, and when I feel the prick of the needle, I turn, and, without stopping to look for the bullet, immediately give chase. I am, of course, not able to overtake a man on a racing machine, but still I follow him some distance. Then the poison begins to take effect—the more rapidly from the violent exercise—and presently I drop insensible. Later on, my body is found. There are no marks of violence, and probably the needle-puncture escapes observation at the post-mortem, in which case the verdict will be death from heart-failure. Even if the poison and the puncture are discovered, there is no clue. The bullet lies some streets away, and is probably picked up by some boy or passing stranger, who cannot conjecture its use, and who would never connect it with the man who was found dead. You will admit that the whole plan has been worked out with surprising completeness and foresight."
"Yes," I answered; "there is no doubt that the fellow is a most infernally clever scoundrel. May I ask if you have any idea who he is?"
"Well," Thorndyke replied, "seeing that, as Carlyle has unkindly pointed out, clever people are not in an overwhelming majority, and that, of the clever people whom I know, only a very few are interested in my immediate demise, I am able to form a fairly probable conjecture."
"And what do you mean to do?"
"For the present I shall maintain an attitude of masterly inactivity and avoid the night air."
"But, surely," I exclaimed, "you will take some measures to protect yourself against attempts of this kind. You can hardly doubt now that your accident in the fog was really an attempted murder."
"I never did doubt it, as a matter of fact, although I prevaricated at the time. But I have not enough evidence against this man at present, and, consequently, can do nothing but show that I suspect him, which would be foolish. Whereas, if I lie low, one of two things will happen; either the occasion for my removal (which is only a temporary one) will pass, or he will commit himself—will put a definite clue into my hands. Then we shall find the air-cane, the bicycle, perhaps a little stock of poison, and certain other trifles that I have in my mind, which will be good confirmatory evidence, though insufficient in themselves. And now, I think, I must really adjourn this meeting, or we shall be good for nothing to-morrow."
It Might Have Been
It was now only a week from the date on which the trial was to open. In eight days the mystery would almost certainly be solved (if it was capable of solution), for the trial promised to be quite a short one, and then Reuben Hornby would be either a convicted felon or a free man, clear of the stigma of the crime.
For several days past, Thorndyke had been in almost constant possession of the laboratory, while his own small room, devoted ordinarily to bacteriology and microscopical work was kept continually locked; a state of things that reduced Polton to a condition of the most extreme nervous irritation, especially when, as he told me indignantly, he met Mr. Anstey emerging from the holy of holies, grinning and rubbing his hands and giving utterance to genial but unparliamentary expressions of amused satisfaction.
I
