towards eleven o'clock at night the fog began slightly to lift. as kerry crossed the bridge over limehouse canal he could vaguely discern the dirty water below, and street lamps showed dimly, surrounded each by a halo of yellow mist. fog signals were booming on the railway, and from the great docks in the neighborhood mechanical clashings and hammerings were audible.

turning to the right, kerry walked on for some distance, and then suddenly stepped into the entrance to a narrow cul-de-sac and stood quite still.

a conviction had been growing upon him during the past twelve hours that someone was persistently and cleverly dogging his footsteps. he had first detected the presence of this mysterious follower outside the house of sin sin wa, but the density of the fog had made it impossible for him to obtain a glimpse of the man's face. he was convinced, too, that he had been followed back to leman street, and from there to new scotland yard. now, again he became aware of this persistent presence, and hoped at last to confront the spy.

below footsteps, the footsteps of someone proceeding with the utmost caution, came along the pavement. kerry stood close to the wall of the court, one hand in a pocket of his overall, waiting and chewing.

nearer came the footsteps—and nearer. a shadowy figure appeared only a yard or so away from the watchful chief inspector. thereupon he acted.

with one surprising spring he hurled himself upon the unprepared man, grasped him by his coat collar, and shone the light of an electric torch fully into his face.

“hell!” he snapped. “the smart from spinker's!”

the ray of the torch lighted up the mean, pinched face of brisley, blanched now by fright, gleamed upon the sharp, hooked nose and into the cunning little brown eyes. brisley licked his lips. in kerry's muscular grip he bore quite a remarkable resemblance to a rat in the jaws of a terrier.

“ho, ho!” continued the chief inspector, showing his teeth savagely. “so we let scotland yard make the pie, and then we steal all the plums, do we?”

he shook the frightened man until brisley's broad-brimmed bowler was shaken off, revealing the receding brow and scanty neutral-colored hair.

“we let scotland yard work night and day, and then we present our rat-faced selves to mr. monte irvin and say we have 'found the lady' do we?” another vigorous shake followed. “we track chief inspectors of the criminal investigation department, do we? we do, eh? we are dirty, skulking mongrels, aren't we? we require to be kicked from limehouse to paradise, don't we?” he suddenly released brisley. “so we shall be!” he shouted furiously.

hot upon the promise came the deed.

brisley sent up a howl of pain as kerry's right brogue came into violent contact with his person. the assault almost lifted him off his feet, and hatless as he was he set off, running as a man runs whose life depends upon his speed. the sound of his pattering footsteps was echoed from wall to wall of the cul-de-sac until finally it was swallowed up in the fog.

kerry stood listening for some moments, then, directing a furious kick upon the bowler which lay at his feet, he snapped off the light of the torch and pursued his way. the lesser mystery was solved, but the greater was before him.

he had made a careful study of the geography of the neighborhood, and although the fog was still dense enough to be confusing, he found his way without much difficulty to the street for which he was bound. some fifteen paces along the narrow thoroughfare he came upon someone standing by a closed door set in a high brick wall. the street contained no dwelling houses, and except for the solitary figure by the door was deserted and silent. kerry took out his torch and shone a white ring upon the smiling countenance of detective-sergeant coombes.

“if that smile gets any worse,” he said irritably, “they'll have to move your ears back. anything to report?”

“sin sin wa went to bed an hour ago.”

“any visitors?”

“no.”

“has he been out?”

“no.”

“got the ladder?”

“yes.”

“all quiet in the neighborhood?”

“all quiet.”

“good.”

the street in which this conversation took place was one running roughly parallel with that in which the house of sin sin wa was situated. a detailed search of the chinaman's premises had failed to bring to light any scrap of evidence to show that opium had ever been smoked there. of the door described by mollie gretna, and said to communicate with the adjoining establishment, not a trace could be found. but the fact that such a door had existed did not rest solely upon mollie's testimony. from one of the “beat-ups” interviewed that day, kerry had succeeded in extracting confirmatory evidence.

inquiries conducted in the neighborhood of poplar had brought to light the fact that four of the houses in this particular street, including that occupied by sin sin wa and that adjoining it, belonged to a certain mr. jacobs, said to reside abroad. mr. jacob's rents were collected by an estate agent, and sent to an address in san francisco. for some reason not evident to this man of business, mr. jacobs demanded a rental for the house next to sin sin wa's, which was out of all proportion to the value of the property. hence it had remained vacant for a number of years. the windows were broken and boarded up, as was the door.

kerry realized that the circumstance of the landlord of “the house of a hundred raptures” being named jacobs, and the lessee of the cubanis cigarette company's premises in old bond street being named isaacs, might be no more than a coincidence. nevertheless it was odd. he had determined to explore the place without unduly advertising his intentions.

two modes of entrance presented themselves. there was a trap on the roof, but in order to reach it access would have to be obtained to one of the other houses in the row, which also possessed a roof-trap; or there were four windows overlooking a little back yard, two upstairs and two down.

by means of a short ladder which coombes had brought for the purpose kerry climbed on to the wall and dropped into the yard.

“the jemmy!” he said softly.

coombes, also mounting, dropped the required implement. kerry caught it deftly, and in a very few minutes had wrenched away the rough planking nailed over one of the lower windows, without making very much noise.

“shall i come down?” inquired coombes in muffled tones from the top of the wall.

“no,” rapped kerry. “hide the ladder again. if i want help i'll whistle. catch!”

he tossed the jemmy up to coombes, and coombes succeeded in catching it. then kerry raised the glass-less sash of the window and stepped into a little room, which he surveyed by the light of his electric torch. it was filthy and littered with rubbish, but showed no sign of having been occupied for a long time. the ceiling was nearly black, and so were the walls. he went out into a narrow passage similar to that in the house of sin sin wa and leading to a stair.

walking quietly, he began to ascend. mollie gretna's description of the opium-house had been most detailed and lurid, and he was prepared for some extravagant scene.

he found three bare, dirty rooms, having all the windows boarded up.

“hell!” he said succinctly.

resting his torch upon a dust-coated ledge of the room, which presumably was situated in the front of the house, he deposited a cud of chewing-gum in the empty grate and lovingly selected a fresh piece from the packet which he always carried. once more chewing he returned to the narrow passage, which he knew must be that in which the secret doorway had opened.

it was uncarpeted and dirty, and the walls were covered with faded filthy paper, the original color and design of which were quite lost. there was not the slightest evidence that a door had ever existed in any part of the wall. following a detailed examination kerry returned his magnifying glass to the washleather bag and the bag to his waistcoat pocket.

“h'm,” he said, thinking aloud, “sin sin wa may have only one eye, but it's a good eye.”

he raised his glance to the blackened ceiling of the passage, and saw that the trap giving access to the roof was situated immediately above him. he directed the ray of the torch upon it. in the next moment he had snapped off the light and was creeping silently towards the door of the front room.

the trap had moved slightly!

gaining the doorway, kerry stood just inside the room and waited. he became conscious of a kind of joyous excitement, which claimed him at such moments; an eagerness and a lust of action. but he stood perfectly still, listening and waiting.

there came a faint creaking sound, and a new damp chilliness was added to the stale atmosphere of the passage. someone had quietly raised the trap.

cutting through the blackness like a scimitar shone a ray of light from above, widening as it descended and ending in a white patch on the floor. it was moved to and fro. then it disappeared. another vague creaking sound followed—that caused by a man's weight being imposed upon a wooden framework.

finally came a thud on the bare boards of the floor.

complete silence ensued. kerry waited, muscles tense and brain alert. he even suspended the chewing operation. a dull, padding sound reached his ears.

from the quality of the thud which had told of the intruder's drop from the trap to the floor, kerry had deduced that he wore rubber-soled shoes. now, the sound which he could hear was that of the stranger's furtive footsteps. he was approaching the doorway in which kerry was standing.

just behind the open door kerry waited. and unheralded by any further sound to tell of his approach, the intruder suddenly shone a ray of light right into the room. he was on the threshold; only the door concealed him from kerry, and concealed kerry from the new-comer.

the disc of light cast into the dirty room grew smaller. the man with the torch was entering. a hand which grasped a magazine pistol appeared beyond the edge of the door, and kerry's period of inactivity came to an end. leaning back he adroitly kicked the weapon from the hand of the man who held it!

there was a smothered cry of pain, and the pistol fell clattering on the floor. the light went out, too. as it vanished kerry leapt from his hiding-place. snapping on the light of his own pocket lamp, he ran out into the passage.

crack! came the report of a pistol.

kerry dropped flat on the floor. he had not counted on the intruder being armed with two pistols! his pocket lamp, still alight, fell beside him, and he lay in a curiously rigid attitude on his side, one knee drawn up and his arm thrown across his face.

carefully avoiding the path of light cast by the fallen torch, the unseen stranger approached silently. pistol in hand, he bent, nearer and nearer, striving to see the face of the prostrate man. kerry lay deathly still. the other dropped on one knee and bent closely over him....

swiftly as a lash kerry's arm was whipped around the man's neck, and helpless he pitched over on to his head! uttering a dull groan, he lay heavy and still across kerry's body.

“flames!” muttered the chief inspector, extricating himself; “i didn't mean to break his neck.”

he took up the electric torch, and shone it upon the face of the man on the floor. it was a dirty, unshaven face, unevenly tanned, as though the man had worn a beard until quite recently and had come from a hot climate. he was attired in a manner which suggested that he might be a ship's fireman save that he wore canvas shoes having rubber soles.

kerry stood watching him for some moments. then he groped behind him with one foot until he found the pistol, the second pistol which the man had dropped as he pitched on his skull. kerry picked it up, and resting the electric torch upon the crown of his neat bowler hat—which lay upon the floor—he stooped, pistol in hand, and searched the pockets of the prostrate man, who had begun to breathe stertorously. in the breast pocket he found a leather wallet of good quality; and at this he stared, a curious expression coming into his fierce eyes. he opened it, and found treasury notes, some official-looking papers, and a number of cards. upon one of these cards be directed the light, and this is what he read:

lord wrexborough

great cumberland place, v. 1

“to introduce 719. w.”

“god's truth!” gasped kerry. “it's the man from whitehall!”

the stertorous breathing ceased, and a very dirty hand was thrust up to him.

“i'm glad you spoke, chief inspector kerry,” drawled a vaguely familiar voice. “i was just about to kick you in the back of the neck!”

kerry dropped the wallet and grasped the proffered hand. “719” stood up, smiling grimly. footsteps were clattering on the stairs. coombes had heard the shot.

“sir,” said kerry, “if ever you need a testimonial to your efficiency at this game, my address is sixty-seven spenser road, brixton. we've met before.”

“we have, chief inspector,” was the reply. “we met at kazmah's, and later at a certain gambling den in soho.”

the pseudo fireman dragged a big cigar-case from his hip-pocket.

“i'm known as seton pasha. can i offer you a cheroot?”