the affair was getting interesting. the conversation was proceeding, too, on lines more or less as grey had expected. he had thought the whole matter out, weighing up the pros and cons of the situation, but the more he debated the thing in his mind the more sure was he that he was on the right track. but for a miscalculation on the part of certain people the mystery of the sundial might have sunk into eternal oblivion. by the irony of fate the very man who could piece together the tangled sections of the puzzle was at hand to do so. for the most part, people regarded the tragedy which had involved the lives of mistress and maid as little more than coincidence. but there were others who, from the first, had insisted that there was mystery calling for solution. grey was now in possession of information calculated to startle the public, and plenty of newspapers would have been only too pleased to pay a fancy price for what he had to sell. there was one flaw, and only one, in his line of argument, but that for the present was absolutely fatal—he was still in the dark as to how the thing had been brought about.
as to the main issue, he was clear enough in his mind. he knew that to all intents and purposes his information was not of the kind which would have been likely to satisfy a judge and jury. but it seemed that he was about to pick up the missing link, and he listened all the more eagerly to what was going on in the next compartment. bark put his strange question again. he still appeared to be anxious to know if there was such a thing as intermittent electricity. and still swift preserved the same strange silence. but bark was not to be put off by the sullen reticence of his companion.
"take your time, my buck," he said. "don't hurry. don't commit yourself to anything likely to be used in evidence against you afterwards."
"why do you want to know?" swift demanded fiercely.
bark laughed in a wholly good-natured manner. he appeared to be exceedingly sure of his ground.
"well, let us say that i am a humble seeker after knowledge," he said. "because i am a wanderer on the face of the earth it doesn't follow that i lack scientific yearnings. if i had been caught young enough i should have been an eminent scientist myself before now. i have worked out many clever little things which would astonish you if you knew. but ever since marconi invented wireless telegraphy and the other man hit upon telephones without lines i have been dreaming of wireless electricity. mind you, it is bound to come sooner or later, and it is all the more likely to arrive because it is so impossible."
"then why worry about it?" swift murmured.
"my dear fellow, you have answered your own question. because the thing is impossible, it is so easy. i don't mind admitting that i have tried a few experiments myself, but hitherto without success. still, it won't be so very long before the whole world is lighted with a fluid which will supply burners without wires. sounds fascinating, doesn't it? at any rate, it fascinated me to the exclusion of everything else. i tried to puzzle it out in the same way that marconi puzzled out his invention. in my mind's eye, i could see a big fire station, say where my glass is, and a big factory where yours stands. by the use of powerful induction coils it seemed to me that i could force the power into the factory lamps without the aid of wires. isn't that the way they propose to work telephones?"
"i don't know anything about it," swift said sullenly.
"oh, yes, you do," bark said, with sudden impatience. "you know all about it. and, what's more, a successful attempt has been made within a mile or so of this very spot. more than once, when i was trying my experiments, it occurred to me to come to england to discuss the matter with arnold rent. i didn't do so for reasons which i will not go into now. but when business compelled me to come to this country and see rent, i wasn't surprised to find that he was working on precisely the same thing. but you know that just as well as i do. what is the good of pretending you don't?"
"it pleases you to say so," swift murmured.
"yes, and it will please me to prove it before long, if you take that line. mind you, i should not have known it if it hadn't been for a mere accident. perhaps you will deny that there is any connection between what we are talking about and the mysterious death of my sister, to say nothing of mrs. charlock?"
a sudden exclamation broke from swift. he seemed to be startled and alarmed. from his hiding-place grey could almost imagine the satisfied grin on bark's face.
"take your time," the latter said playfully. "i won't hurry you, for we sha'n't part till i get to the bottom of this business. i asked you a plain question and i mean to have a plain answer. have you or has arnold rent made any startling discovery in the direction of intermittent electricity? is the thing within the range of practical politics?"
it was a long time before swift replied. grey could hear him playing with his glass. he could hear the uneasy shuffle of the unfortunate man's body. when the electrician did speak his voice was both timid and hesitating.
"you have no business to ask me this," he said. "if we have made the discovery you speak of, it lies entirely between arnold rent and myself. a discovery like that means a huge fortune to the author. the richest man in the world would be a pauper alongside the man who could reduce such a discovery to practical uses."
"what a chap it is to talk!" bark said impatiently. "why don't you come to the point? you know perfectly well that you dare not refuse the information i am after."
"we won't go into that," said swift, with some attempt at dignity. "you will, perhaps, be disappointed to hear that i know nothing about intermittent electricity. if there has been a discovery in that direction, it is rent's and not mine. he is a far cleverer man than i am. i am a child compared with him."
"not if you kept off the drink," bark said impatiently.
"well, i didn't keep off the drink. what's more, i never shall. and eventually it will be the death of me," swift said, with a snarl. "for a long time past i have known that my employer was on the verge of a fresh and startling plunge into the sea of discovery. to some extent rent confided in me, but exactly what he was after he kept to himself. but by piecing one or two little bits of information together i arrived at the conclusion that wireless electricity was the goal. i could tell that from certain new pieces of machinery which were set up in the office. of course, i said nothing. i knew it was useless to ask questions. and, besides, i felt that sooner or later i should be taken into my employer's confidence. i gathered that things were progressing in a satisfactory manner, when, all at once, the whole scheme of experiments was abandoned and the machinery was destroyed. and now you know pretty well as much as i can tell you."
bark chuckled unpleasantly.
"i don't think so," he replied. "still, i am going to take your word for it as far as it goes. i should like to know the exact date that the machinery was destroyed."
"how could i tell you that?" swift demanded. "it happened some time ago."
"i have no doubt," bark went on, in the same sardonic way. "that i am quite prepared to believe. but let me refresh your memory. isn't it a fact that the machinery was destroyed and the experiments came to an abrupt conclusion on the day following my sister's death? didn't arnold rent come down to the office that same day and break up all his machinery, with the excuse that he had made a mistake in his calculations and would have to begin all over again? i don't say that those were the precise words, though i am prepared to swear that that was the purport of them."
"rent told you himself, then," swift exclaimed.
"no, he didn't," bark chuckled. "but you have just done so. come, don't pretend you are ignorant of what i am driving at. tell me all i want to know, and it will be the best day's work you ever did in your life. if you will make a clean breast of the whole thing i will put a thousand pounds in your pocket. a little later i'll pay you double that sum. think what that will mean to you! you could set up for yourself. you could go off to america and make a fortune. all you have to do is to keep straight and you'll be a millionaire in five years. that is the prospect, on the one hand. but there is another point of view which i want to present to your notice. which would you rather have—the career i have indicated, or find yourself laid by the heels, charged with being accessory before and after the fact to a deliberate and cold-blooded murder? i don't want to speak more plainly."
a strange, inarticulate cry rose from the compartment; there was a sudden rush on the part of swift, and a moment later he blundered headlong through the door into the darkness.
"that's all right," bark said, sotto voce. "i think i've touched him on the raw. the next time we meet he will tell me everything. he will be like wax in my hands in future."