said Usher, "Last-Trick Todd counts for a great deal in this rum affair."
He stretched himself once more before the fire and continued talking in his expansive, radiantly explanatory style.
"To begin with, on the face of it, there is no mystery here at all. It is not mysterious, it is not even odd, that a jailbird should take his gun to Pilgrim's Pond. Our people aren't like the English, who will forgive a man for being rich if he throws away money on hospitals or horses. Last-Trick Todd has made himself big by his own considerable abilities; and there's no doubt that many of those on whom he has shown his abilities would like to show theirs on him with a shot-gun. Todd might easily get dropped by some man he'd never even heard of; some labourer he'd locked out, or some clerk in a business he'd busted. Last-Trick is a man of mental endowments and a high public character; but in this country the relations of employers and employed are considerably strained.
"That's how the whole thing looks supposing this Rian made for Pilgrim's Pond to kill Todd. So it looked to me, till another little discovery woke up what I have of the detective in me. When I had my prisoner safe, I picked up my cane again and strolled down the two or three turns of country road that brought me to one of the side entrances of Todd's grounds, the one nearest to the pool or lake after which the place is named. It was some two hours ago, about seven by this time; the moonlight was more luminous, and I could see the long white streaks of it lying on the mysterious mere with its grey, greasy, half-liquid shores in which they say our fathers used to make witches walk until they sank. I'd forgotten the exact tale; but you know the place I mean; it lies north of Todd's house towards the wilderness, and has two queer wrinkled trees, so dismal that they look more like huge fungoids than decent foliage. As I stood peering at this misty pool, I fancied I saw the faint figure of a man moving from the house towards it, but it was all too dim and distant for one to be certain of the fact, and still less of the details. Besides, my attention was very sharply arrested by something much closer. I crouched behind the fence which ran not more than two hundred yards from one wing of the great mansion, and which was fortunately split in places, as if specially for the application of a cautious eye. A door had opened in the dark bulk of the left wing, and a figure appeared black against the illuminated interior—a muffled figure bending forward, evidently peering out into the night. It closed the door behind it, and I saw it was carrying a lantern, which threw a patch of imperfect light on the dress and figure of the wearer. It seemed to be the figure of a woman, wrapped up in a ragged cloak and evidently disguised to avoid notice; there was something very strange both about the rags and the furtiveness in a person coming out of those rooms lined with gold. She took cautiously the curved garden path which brought her within half a hundred yards of me—, then she stood up for an instant on the terrace of turf that looks towards the slimy lake, and holding her flaming lantern above her head she deliberately swung it three times to and fro as for a signal. As she swung it the second time a flicker of its light fell for a moment on her own face, a face that I knew. She was unnaturally pale, and her head was bundled in her borrowed plebeian shawl; but I am certain it was Etta Todd, the millionaire's daughter.
"She retraced her steps in equal secrecy and the door closed behind her again. I was about to climb the fence and follow, when I realized that the detective fever that had lured me into the adventure was rather undignified; and that in a more authoritative capacity I already held all the cards in my hand. I was just turning away when a new noise broke on the night. A window was thrown up in one of the upper floors, but just round the corner of the house so that I could not see it; and a voice of terrible distinctness was heard shouting across the dark garden to know where Lord Falconroy was, for he was missing from every room in the house. There was no mistaking that voice. I have heard it on many a political platform or meeting of directors; it was Ireton Todd himself. Some of the others seemed to have gone to the lower windows or on to the steps, and were calling up to him that Falconroy had gone for a stroll down to the Pilgrim's Pond an hour before, and could not be traced since. Then Todd cried 'Mighty Murder!' and shut down the window violently; and I could hear him plunging down the stairs inside. Repossessing myself of my former and wiser purpose, I whipped out of the way of the general search that must follow; and returned here not later than eight o'clock.
"I now ask you to recall that little Society paragraph which seemed to you so painfully lacking in interest. If the convict was not keeping the shot for Todd, as he evidently wasn't, it is most likely that he was keeping it for Lord Falconroy; and it looks as if he had delivered the goods. No more handy place to shoot a man than in the curious geological surroundings of that pool, where a body thrown down would sink through thick slime to a depth practically unknown. Let us suppose, then, that our friend with the cropped hair came to kill Falconroy and not Todd. But, as I have pointed out, there are many reasons why people in America might want to kill Todd. There is no reason why anybody in America should want to kill an English lord newly landed, except for the one reason mentioned in the pink paper—that the lord is paying his attentions to the millionaire's daughter. Our crop-haired friend, despite his ill-fitting clothes, must be an aspiring lover.
"I know the notion will seem to you jarring and even comic; but that's because you are English. It sounds to you like saying the Archbishop of Canterbury's daughter will be married in St George's, Hanover Square, to a crossing-sweeper on ticket-of-leave. You don't do justice to the climbing and aspiring power of our more remarkable citizens. You see a good-looking grey-haired man in evening-dress with a sort of authority about him, you know he is a pillar of the State, and you fancy he had a father. You are in error. You do not realize that a comparatively few years ago he may have been in a tenement or (quite likely) in a jail. You don't allow for our national buoyancy and uplift. Many of our most influential citizens have not only risen recently, but risen comparatively late in life. Todd's daughter was fully eighteen when her father first made his pile; so there isn't really anything impossible in her having a hanger-on in low life; or even in her hanging on to him, as I think she must be doing, to judge by the lantern business. If so, the hand that held the lantern may not be unconnected with the hand that held the gun. This case, sir, will make a noise."
"Well," said the priest patiently, "and what did you do next?"
"I reckon you'll be shocked," replied Greywood Usher, "as I know you don't cotton to the march of science in these matters. I am given a good deal of discretion here, and perhaps take a little more than I'm given; and I thought it was an excellent opportunity to test that Psychometric Machine I told you about. Now, in my opinion, that machine can't lie."
"No machine can lie," said Father Brown; "nor can it tell the truth."
"It did in this case, as I'll show you," went on Usher positively. "I sat the man in the ill-fitting clothes in a comfortable chair, and simply wrote words on a blackboard; and the machine simply recorded the variations of his pulse; and I simply observed his manner. The trick is to introduce some word connected with the supposed crime in a list of words connected with something quite different, yet a list in which it occurs quite naturally. Thus I wrote 'heron' and 'eagle' and 'owl', and when I wrote 'falcon' he was tremendously agitated; and when I began to make an 'r' at the end of the word, that machine just bounded. Who else in this republic has any reason to jump at the name of a newly-arrived Englishman like Falconroy except the man who's shot him? Isn't that better evidence than a lot of gabble from witnesses—if the evidence of a reliable machine?"
"You always forget," observed his companion, "that the reliable machine always has to be worked by an unreliable machine."
"Why, what do you mean?" asked the detective.
"I mean Man," said Father Brown, "the most unreliable machine I know of. I don't want to be rude; and I don't think you will consider Man to be an offensive or inaccurate description of yourself. You say you observed his manner; but how do you know you observed it right? You say the words have to come in a natural way; but how do you know that you did it naturally? How do you know, if you come to that, that he did not observe your manner? Who is to prove that you were not tremendously agitated? There was no machine
