as was only natural in the circumstances, the tragic death of mrs. john charlock created a profound sensation. the accident to the french maid had set most people talking, but the unfortunate end of the mistress in the same mysterious fashion bade fair to become a general topic of conversation. the whole thing was so simple, and yet so strange and out of the common. a score of theories were set on foot, but not one of them worked out in a satisfactory manner. the police were plainly at fault, and though inspector battley was reinforced by a colleague or two from scotland yard, the end of the week found the authorities no nearer the solution of the trouble than they had been at the beginning of the inquiry.
as for grey and tanza, they went their own way, which was by no means the way taken by the police. ephraim bark was still in the neighbourhood, and his movements were watched by tanza and grey with a patient care which would have astonished that worthy had he only known of it. grey had his own theory, which he was developing slowly. it was an integral part of his theory that bark could have said a great deal more had he chosen to do so. and there was yet another person whom grey was keeping a close eye upon. he had by no means forgotten the torn photograph he had found in the french maid's room. he did not ignore the information as to arnold rent's strange friendship with the dead frenchwoman. and there was another item of which, as yet, grey had said nothing to anyone. he was coming to his conclusions now—conclusions so strange and startling that he hardly dared trust himself to believe them. a week passed slowly, during which nothing particular had happened, and arnold rent appeared to get no better. so far as grey could gather, his brother scientist had had a nasty fall, which, for the time being, had affected his intellect. there was a good deal of mystery about the affair, and grey was at some pains to make the acquaintance of the doctor who was attending rent. the thing was accomplished at length through tanza, who made some pretext for inviting the doctor to dine aboard his yacht. very cautiously and patiently grey led up to the subject which was next his heart. the thing was so naturally done, and tanza played into his hands so cleverly, that the doctor fell into the trap at once.
"oh, so you know mr. rent," he said, as he lay back in a deck-chair smoking a cigar. "an exceedingly clever fellow, who, unless i am much mistaken, will make his mark in the world yet. a strange illness that of his, by the way."
"i was going to ask you about that," grey murmured. "i hear he is suffering from the effects of a severe fall. i hope the accident won't leave any permanent injury."
"i don't think so," the doctor said. "i had a specialist down to-day and he takes a very sanguine view of the case. all that is wanted is rest. for the moment my patient has a partial lapse of memory—a sort of hiatus of a week. in other words, he can recollect everything perfectly well, except that the past seven days are a complete blank to him. and during the last day or so before his fall he had been engaged in some experiment, the results of which ought to be placed on record at once. this seems to worry him terribly. it has affected him to such an extent that he is making himself seriously ill over it. imagine a man who has some great commercial deal on and has to buy or sell at a given moment suddenly forgetting the very thing he has to do. that appears to be rent's case. anybody might suppose that he had committed murder and had forgotten to hide the clue, by the way he goes on."
a sudden exclamation broke from grey, which he checked immediately. the doctor looked up inquiringly.
"a twinge of pain," he muttered. "nothing much to trouble about. a most interesting case, doctor. and you think that in time rent will be quite himself again?"
"oh, i am certain of it. if i could only prevent him from worrying, i should have had him right by this time. of course, what i am saying to you is in strict confidence."
grey and tanza gave the desired assurance, and the conversation became more general. when the doctor left he was accompanied by grey, who said he had business on shore. he left the man of medicine at the corner of a street leading up from the quay and proceeded along the shore to arnold rent's workshop. he stood for a long time making a mental calculation, after which he walked several times round the building, examining the ground carefully as if in search of something. apparently, nothing had rewarded his efforts, for he shook his head impatiently and crossed over to the office, in the window of which a light was burning. someone inside was singing a snatch from a comic opera in a loud, blustering voice. an unsteady, flickering shadow crossed the blind once or twice, and grey's features broke into a grim smile.
"friend swift has broken out again," he murmured. "what a pity so clever a man should be the victim of a curse like this! still, his misfortune is my opportunity, and if there is anything he can tell me, now is the time to learn it."
without further hesitation, grey pushed his way into the office, which was flooded with half a dozen powerful electric lights. the large slate-topped table had been cleared of all kinds of electric appliances. there were the remains of a supper at one end, flanked by two or three empty bottles. the reserved and saturnine swift seemed to have changed altogether. his dark features wore a look of reckless gaiety; his sombre eyes were shining. he did not appear to be in the least surprised to see grey; in fact, he might have been expecting him. his unsteady gait and thick speech, however, told their tale.
"hallo!" he exclaimed. "so you have come to pay me a visit? you have come here to learn the secrets of the prison-house? ah, my dear fellow, you are very clever, but your tuppenny discoveries are nothing compared to what we are on the track of here. for we've got it, my boy, we've got it. you remember the dream you used to indulge in at school?"
"intermittent electricity," grey exclaimed. "a wireless current. you don't mean to say you have got to the bottom of that!"
swift seemed to be sober for the moment. a sullen, obstinate look came over his face, but he did not appear to be half so agitated as was his visitor. only for an instant did it occur to the dull brain that secrets were being betrayed, and in the same instant grey saw that he had gone too far. he changed the subject with a quickness that fogged swift.
"what did i say to you?" the latter asked, as he passed his hand across his face. "i hope i didn't make a fool of myself?"
"not at all," grey hastened to say. "besides, i haven't come here to-night in the guise of a spy."
"quite right," swift said, with a sudden change to amiability. "of course, you didn't. you are too much of a gentleman for that. now, arnold rent isn't a gentleman, for all his pretence. he treats me like a dog. he uses my brains and then passes off my discoveries as his own. he knows that no one else will employ me, that nobody else would look twice at a man who is often drunk a week at a time. but i can't help it, grey. upon my word, i can't. i inherit it from my father. i fight against it and fight against it till the sweat runs off my forehead and my limbs refuse to carry me. then, all at once, everything grows misty and i can't recollect anything more till i am gloriously drunk. that's why rent puts up with me. but he is a blackguard, all the same, and he will come to a bad end. don't you trust him, grey. don't you trust him, or it will be all the worse for you. now come and sit down and make a night of it with me."
grey declined the tempting offer.
"i can't stay many minutes," he said. "i merely looked in to see how rent was getting on."
"he is bad, downright bad," swift said, with a chuckle. "and he has got something on his mind. there is something he has to do, some piece of infernal rascality to conceal, and his brain fails him, and he can't for the life of him think what it is. and all the time the trail is open for anybody to pick up, and he might find himself in trouble at any moment. that is what's wrong with arnold rent, and i can't say i'm sorry. do i know what he has been doing? no, i don't, and i don't care. you think that his accident is the result of a fall. nothing of the kind, my boy! he and that blackguard, ephraim bark, had a quarrel the other night and bark knocked him into the fender. how do i know that? well, you see, i came in directly afterwards and rent tried to persuade me that nobody had been here. unluckily for him there was a cheap cigarette on the table, and i guessed at once bark had been smoking. but why don't you sit down and make yourself comfortable? you are different from me. you always know when to leave off—when you have had enough."
half-defiantly, swift helped himself to another strong glass of whisky, and a moment or two later was lying back in an armchair, more or less asleep. it was a good chance for grey to get away and he seized it promptly.
"that's a lucky call," he muttered. "now i see what it was that puzzled me. rent has learnt the secret of the intermittent current and he has been using it. it will be my turn next."
