wilfrid brushed cotter aside as if he had been a fly, and flung himself against the door, heedless of its weight and strength, but it was of stout oak and he might as well have hurled himself against a brick wall. but the sullen blow echoed through the house and there were indications of alarm and confusion in the library. it was useless to bruise himself against the obstacle and wilfrid looked hastily around for some weapon. his eyes fell upon a trophy of bill-hooks and battleaxes. he snatched one of the latter and attacked the door in earnest. the third blow smashed in a panel and a crossbar so that it was possible to crawl through into the library.

as far as he could see the place was empty. one of the windows was wide open, which was perhaps fortunate, for the overpowering scent hung on the air and the odour of it was keen upon wilfrid's nostrils. beyond doubt one of those mysterious fireballs had been lighted here. but there was no time to inquire into this. what had become of samuel flower? he must have been there a few minutes ago. certainly somebody had been in the library. flower's peril now seemed as great as ever. wilfrid strode across towards the window past the mahogany writing-table where flower's letters were scattered about. one letter with little more than a name and address lay on the blotting pad with a wet pen upon it, as if it had fallen suddenly from the writer's hand. eager and excited as he was, wilfrid noted this casually. his search was finished now. as he strode past the table he blundered over a figure lying at his feet which he recognized at once as that of samuel flower. he had to call twice, and the second time sternly, before cotter wriggled through the broken panel and came dazed and frightened into the room.

"there is no danger now," wilfrid said contemptuously. "for the present, at any rate, those mysterious people have gone. now help me to get your master on to this sofa."

"he's dead," cotter muttered. "of course he's dead. if you had been through what he has the last few minutes——"

wilfrid did not deign to argue the point. he curtly motioned cotter to flower's feet, and between them they managed to raise the body of the ship-owner on to the couch. examination proved that cotter was wrong. flower lay still and white and breathless, but wilfrid could see that he breathed and that some faint tinge of colour was coming back into his pendulous cheeks. at a command from wilfrid, cotter went out and returned with a brandy decanter. wilfrid moistened the blanched lips with the stimulant, and after a little while flower opened his eyes in a dull way and gazed stupidly about. for the present he was safe, though it was some time before he showed anything like real consciousness. there was an ugly bruise on his forehead, doubtless the result of a fall.

"i daresay you can give me what i want," wilfrid said to cotter. "is there such a thing in the garden as a house leek? you know the herb i mean—it grows in clumps on the walls. it is capital stuff for bruises and swellings. go and get me some."

"i know where it is to be found," cotter muttered. "but as to going out into the garden, or in the dark——"

"fetch it at once," wilfrid said imperiously. "there is nothing to be frightened of. go and bring it, or i will kick you out of the window."

cotter shambled off into the darkness. he came back presently with a handful of the thick, fleshy leaves, and under wilfrid's direction began to mash them into pulp. the man's manner was so strange that mercer asked the reason.

"i am mad," cotter exclaimed. "we are all mad. there was never anything like this since the world began. i tell you those men have gone. i saw them in the garden—with my own eyes i saw them. and they were as much afraid of the other one as we are of them. what does it mean, sir?"

just for a moment it occurred to wilfrid that cotter had really taken leave of his senses, but his speech was coherent enough and the look of absolute terror had faded from his eyes.

"what other one?" wilfrid asked.

"why, the big man in the livery," cotter replied. "but i forgot—you didn't see him. he came up to the other two with a whip in his hand and lashed them as if they had been dogs. a great nigger, nearly seven feet high."

"a nigger!" wilfrid exclaimed. "what bosh!"

"i assure you it's true, sir," cotter said earnestly. "it was on the other side of the lawn and the light from the window fell full upon his face. i tell you he is a pure-blooded negro. when those other two saw him coming they bolted and he after them. and he used his whip upon them vigorously. don't ask me what it all means, sir. i am not going to stay here. i should be afraid to spend another night under this roof."

wilfrid gave the thing up as hopeless for the present. probably this new phase of the maddening puzzle would solve itself in time. and meanwhile there was beatrice to be thought of. in a few curt words wilfrid sent cotter into the garden to bring miss galloway back to the house. he was to wait in the drawing-room till wilfrid was at liberty again. he was glad to be alone so that he could concentrate attention upon his patient.

flower was rapidly coming to himself and by and by would be able to give an account of what had happened. he opened his eyes from time to time and recognized wilfrid with a flicker of his eyelids. there was nothing, however, but to wait, and wilfrid sat down by the side of the table where the letters were scattered about. without wishing to be curious he did not fail to notice the unfinished letter on which the wet pen was still lying. it was addressed as he saw to a firm called darton & co. then followed the words:—

"dear sirs, re mr. wil——"

here the letter stopped abruptly as if the writer had been interrupted. it struck wilfrid as a coincidence that darton & co. was the firm from which he had borrowed the money to set himself up in business. but doubtless there were other firms of darton & co., and in any case the matter was not worth thinking about. besides, flower was sitting up now and holding his hands to his temples.

"what does it all mean?" he whispered. "and what is the matter with the door? why is the window open? ah, i begin to recollect. cotter had given me some information which he had got from london by telephone and i was just writing a letter.... it was a most extraordinary smell, mercer. i don't think i ever smelt anything like it. i rose to open the window and after that i remember nothing till i came to my senses on the sofa and you were bending over me. what can it mean?"

"i think you know as much about it as i do," wilfrid said guardedly. "beyond question, a determined attempt to murder you has been made by some person or persons whom you know just as much about as i do. but i had better tell you what has happened in another part of the house."

wilfrid told his tale briefly, not forgetting to touch upon cotter's terror and the admissions which had come from the confidential clerk in a moment of peril.

"it is not for me to say anything about it," wilfrid concluded, "but seeing that i have already met the men who manipulate these kind of things through the symbol of the knotted string, why, naturally, i must draw my own inferences. i will not ask you for your confidence, and you may tell me as little or as much as you like. it seems only fair to conclude that you have somehow incurred the displeasure of these people. if i can help you——"

flower shook his head despondently. evidently he was in no mood to be communicative.

"i don't think i'll trouble you," he said. "that this sort of thing should go on in england in the twentieth century is outrageous. fortunately no one knows anything about it but yourself and my niece and cotter, and you will see that the less said the better. i'll place the matter in the hands of a detective, and before the end of the week we shall be safe from a repetition of outrages of this kind."

flower spoke rationally, but he was terribly shaken. the ship-owner rose to his feet as if the interview were ended.

"you wouldn't care for me to stay all night, i suppose?" wilfrid asked. "i will if you like."

"not the least occasion, my dear sir. i have a revolver, and cotter and i can sit up till daylight. i am ashamed to have given you all this trouble. don't let me detain you longer."

there was nothing more to be said and wilfrid walked out into the hall. he would have left the house, but hearing his step beatrice came to the door of the drawing-room. at the same time flower's voice was heard demanding cotter.

"i should like to speak to you before you go," beatrice said.