behold me established in rooms in battersea and living retired during the day while i permitted my beard to grow. i had recognized that my mystery of "the scorpion" was the biggest case which had ever engaged the attention of the service de surete, and i was prepared, if necessary, to devote my whole time for twelve months to its solution. i had placed myself in touch with paris, and had had certain papers and licenses forwarded to me. a daily bulletin reached me, and one of these bulletins was sensational.

the body of jean sach had been recovered from the seine. the man had been stabbed to the heart. surveillance of miguel and his associates continued unceasingly, but i had directed that no raids or arrests were to be made without direct orders from me.

i was now possessed of a french motor license and also that of a paris taxi-driver, together with all the other documents necessary to establish the identity of one charles malet. everything was in order. i presented myself—now handsomely bearded—at new scotland yard and applied for a license. the "knowledge of london" and other tests i passed successfully and emerged a fully-fledged cabman!

already i had opened negotiations for the purchase of a dilapidated but seviceable cab which belonged to a small proprietor who had obtained a car of more up-to-date pattern to replace this obsolete one. i completed these negotiations by paying down a certain sum and arranged to garage my cab in the disused stable of a house near my rooms in battersea.

thus i now found myself in a position to appear anywhere at any time without exciting suspicion, enabled swiftly to proceed from point to point and to pursue anyone either walking or driving whom it might please me to pursue. it was a modus operandi which had served me well in paris and which had led to one of my biggest successes (the capture of the french desperado known as "mr. q.") in new york.

i had obtained, via paris, particulars of the recent death of sir frank narcombe, and the circumstances attendant upon his end were so similar to those which had characterized the fate of the grand duke, of van rembold and the others, that i could not for a moment believe them to be due to mere coincidence. acting upon my advice paris advised scotland yard to press for a post mortem examination of the body, but the influence of sir frank's family was exercised to prevent this being carried out—and exercised successfully.

meanwhile, i hovered around the houses, flats, clubs and offices of everyone who had been associated with the late surgeon, noting to what addresses they directed me to drive and who lived at those address. in this way i obtained evidence sufficient to secure three judicial separations, but not a single clue leading to "the scorpion"! no matter.

at every available opportunity i haunted the east-end streets, hoping for a glimpse of the big car and the brown-skinned chauffeur or of my scarred man from paris. i frequented all sorts of public bars and eating-houses used by foreign and asiatics. by day and by night i roamed about the dismal thoroughfares of that depressing district, usually with my flag down to imply that i was engaged.

such diligence never goes long unrewarded. one evening, having discharged a passenger, a mercantile officer, at the east india docks, as i was drifting, watchfully, back through limehouse, i saw a large car pull up just ahead of me in the dark. a man got out and the car was driven off.

two courses presented themselves. i was not sure that this was the car for which i sought, but it strangely resembled it. should i follow the car or the man? a rapid decision was called for. i followed the man.

that i had not been mistaken in the identity of the car shortly appeared. the man took out a cigar and standing on the corner opposite the town hall, lighted it. i was close to him at the time, and by the light of the match, which he sheltered with his hands, i saw the scarred and bearded face! triomphe! it was he!

having lighted his cigar, he crossed the road and entered the saloon of a neighbourhood public-house. locking my cab i, also, entered that saloon. i ordered a glass of bitter beer and glanced around at the object of my interest. he had obtained a glass of brandy and was contorting his hideous face as he sipped the beverage. i laughed.

"have they tried to poison you, mister!" i said.

"ah,pardieu! poison—yes!" he replied.

"you want to have it out of a bottle," i continued confidentially—

"martell's three stars."

he stared at me uncomprehendingly.

"i don't know," he said haltingly. "i have very little english."

"oh, that's it!" i cried, speaking french with a barbarous accent.

"you only speak french?"

"yes, yes," he replied eagerly. "it is so difficult to make oneself understood. this spirit is not cognac, it is some kind of petrol!"

finishing my bitter, i ordered two glasses of good brandy and placed one before "le balafre."

"try that," i said, continuing to speak in french, "you will find it is better."

he sipped from his glass and agreed that i was right. we chatted together for ten minutes and had another drink, after which my dangerous-looking acquaintance wished me good-night and went out. the car had come from the west, and i strongly suspected that my man either lived in the neighbourhood or had come there to keep an appointment. leaving my cab outside the public-house, i followed him on foot, down three colt street to ropemaker street, where he turned into a narrow alley leading to the riverside. it was straight and deserted, and i dared not follow further until he had reached the corner. i heard his footsteps pass right to the end. then the sound died away. i ran to the corner. the back of a wharf building—a high blank wall—faced a row of ramshackle tenements, some of them built of wood; but not a soul was in sight.

i reluctantly returned to the spot at which i had left the cab—and found a constable there who wanted to know what i meant by leaving a vehicle in the street unattended. i managed to enlist his sympathy by telling him that i had been in pursuit of a "fare" who had swindled me with a bad half-crown. the ruse succeeded.

"which street did he go down, mate?" asked the constable.

i described the street and described the scarred man. the constable shook his head.

"sounds like one o' them foreign sailormen," he said. "but i don't know what he can have gone down there for. it's nearly all chinese, that part."

his words came as a revelation; they changed the whole complexion of the case. it dawned upon me even as he spoke the word "chinese" that the golden scorpion which i had seen in the paris cafe was of chinese workmanship! i started my engine and drove slowly to that street in which i had lost the track of "le balafre." i turned the cab so that i should be ready to drive off at a moment's notice, and sat there wondering what my next move should be. how long i had been there i cannot say, when suddenly it began to rain in torrents.

what i might have done or what i had hoped to do is of no importance; for as i sat there staring out at the dismal rain-swept street, a man came along, saw the head-lamps of the cab and stopped, peering in my direction. evidently perceiving that i drove a cab and not a private car, he came towards me.

"are you disengaged?" he asked.

whether it was that i sympathized with him—he had no topcoat or umbrella—or whether i was guided by fate i know not, but as he spoke i determined to give up my dreary vigil for that night. pardieu! but certainly it was fate again!

"well, i suppose i am, sir," i said, and asked him where he wanted to go.

he gave an address not five hundred yards from my own rooms! i thought this so curious that i hesitated no longer.

"jump in," i said; and still seeking in my mind for a link between the scorpion case and china, i drove off, and in less than half an hour, for the streets were nearly empty, arrived at my destination.

the passenger, whose name was dr. keppel stuart, very kindly suggested a glass of hot grog, and i did not refuse his proferred hospitality. when i came out of his house again, the rain had almost ceased, and just as i stooped to crank the car i thought i saw a shadowy figure moving near the end of a lane which led to the tradesmen's entrance of dr. stuart's house. a sudden suspicion laid hold upon me—a horrible doubt.

having driven some twenty yards along the road, i leaned from my seat and looked back. a big man wearing a black waterproof overall was standing looking after me!

remembering how cleverly i had been trailed from miguel's cafe to my flat, in paris (for i no longer doubted that someone had followed me on that occasion), i now perceived that i might again be the object of the same expert's attention. stopping my engine half-way along the next road, i jumped out and ran back, hiding in the bushes which grew beside the gate of a large empty house. i had only a few seconds to wait.

a big closed car, running almost silently, passed before me … and

"le balafre" was leaning out of the window!

at last i saw my chance of finding the headquarters of "the scorpion." alas! the man of the scar was as swift to recognize that possibility as i. a moment after he had passed my stationary cab, and found it to be deserted, his big car was off like the wind, and even before i could step out from the bushes the roar of the powerful engine was growing dim in the distance!

i was detected. i had to deal with dangerously clever people.