Hetherwick realised at once that Mapperley had news, and was waiting there to communicate it. But he looked not so much at Mapperley as at Mapperley's companion. Mapperley, as Hetherwick had remarked to more than one person in the course of those proceedings, concealed his sharpness under an unusually commonplace exterior; he looked, as a rule, like a young man whose ideas rarely soared above a low level. But the Jew was of a different aspect—Hetherwick was not quite sure whether he was rat or ferret. There was subtlety and craft written all over him, from his bright beady eyes to his long, thin, dirty fingers, and before Mapperley spoke his employer felt sure that in this son of Israel the clerk had found a valuable associate.  
"Hullo, Mapperley!" exclaimed Hetherwick. "Waiting for me? You've some news, I suppose?"
 
Mapperley, grave and formal, pointed a finger at the Jew.
 
"Mr. Isidore Goldmark, sir," he said. "Friend of mine. I got him to give me a bit of assistance in this Baseverie and Vivian affair. The fact is, sir, he knows Vivian's—don't you, Issy?"
 
"Thome!" replied Mr. Goldmark, with a grin.
 
"And he knows Baseverie, too," continued Mapperley. "By sight, anyhow. So I got him—for a consideration—to watch for Baseverie's next appearance on that scene, and then, when he did come, to keep an eye on him—trick him, in fact. And Issy's seen him to-night, Mr. Hetherwick, and followed him. Then Issy came to me, and I brought him here."
 
"Good!" said Hetherwick. "Sit down, both of you, and I'll hear about it." He dropped into his own easy chair and again regarding the Jew decided that he was probably a creditable witness. "What do you do at Vivian's?" he asked. "Employed there?"
 
Mr. Goldmark glanced at Mapperley and smiled knowingly. Mapperley nodded.
 
"All confidential, Issy," he said reassuringly. "Going no further."
 
"Of course this is all confidential—and secret," remarked Hetherwick. "I only want to know the precise connection between Vivian's and Mr. Goldmark."
 
"It'th a thort of themi-official, mithter," answered the Jew. "The fact ith, I do a bit o' commith'on work for Vivian'th cuthtomerth, turf you know. Tho'—I'm in and out of an evening. Thee?"
 
"I see," said Hetherwick. "All right! And you know Baseverie?"
 
"Ath well ath I know my own nothe," replied Mr. Goldmark.
 
"How long have you known him?"
 
"Thome time."
 
"Do you know what he is?"
 
"Aint an idea, mithter—and noboody elthe that I knowth of! Liv'th on hith wit'th, I should thay, if you athk me. Wrong 'un!"
 
"Nor where he lives?"
 
"No, mithter! All I knowth ith that he come'th to Vivian'th—now and then."
 
"And you saw him to-night?"
 
"I did, mithter—to-night ath ever wath!"
 
"What time was that?"
 
"About eight o'clock, mithter—near ath I can fix it."
 
"Well, what happened?"
 
"Thith, mithter. He came in about eight, ath I thay. I wath there, doing a bit o' bithneth with another cuthmur. Batheverie, he didn't thtop. He wathn't in the plathe three minuteth, and while he wath in he theemed—to me—to be a bit fidgety—thuthpithious, like. Looked round and about—cautiouth. Then he went—and I followed him. According to inthructionth from Mapperley there."
 
"Where did he go?"
 
"Well, mithter, I'll give you the particularth—in full: when I theth out on a job o' that thort I do it proper. He turned out o' Candlethtick Pathage into the Lane, and he had a drink at a bar there. Then he went to Trafalgar Square Tube. I wath clothe behind him when he booked——"
 
"A moment. Does he know you?"
 
"May jutht know me by thite, mithter, but not enough to exthite any thuthpithion in hith mind if he thaw me there behind him. I never had no truck with him—never thpoke to him."
 
"Well, go on. Where did he book to?"
 
"Warwick Avenue, mithter. Tho did I—of courth. When we got there, I followed him out—at a thafe dithtance. He turned down to the Canal, crothed the bridge, and went down to Thant Mary'th Manthion'th. And there he went in."
 
Hetherwick glanced at Mapperley. Mapperley permitted himself to wink at his employer—respectfully, but knowingly.
 
"Went into St. Mary's Mansions, eh?" said Hetherwick. "Walked straight in?"
 
"Straight in, mithter—front entranth. I thee him, from acroth the road, talking to the man in livery—porter or whatever he hith. I could thee through the glath doorth. Then I thee both of 'em go up in the lift. Tho I waited about a bit, jutht to thee if he'd come out. He did."
 
"Soon?" asked Hetherwick.
 
"He wath inthide about ten minuteth. Then he came out. Alone. Thith time he went in t'other direction. I followed him acroth Paddington Green to Edgware Road Tube, and there—well, to tell you the truth, mithter, there I lotht him! There wath a lot o' people about, and I made thure he'd be going thouth. But he mutht ha' gone wetht. Anyway, I lotht him altogether."
 
"Well—I think you saw enough to be of help," said Hetherwick. "Now—just keep this to yourself, Goldmark." He motioned Mapperley into another room, gave him money for his assistant, and waited until the Jew had gone, shown out by the clerk. "Eleven o'clock!" he remarked, glancing at his watch as Mapperley came back. "Mapperley! we're going out—to St. Mary's Mansions. And after we've been there, and made a call, you'd better come back here with me and take a shake-down for the night—I shall want you in the morning, unless I'm mistaken."
 
It was one of Mapperley's chief virtues that he was always ready to go anywhere and do anything, and he at once accompanied Hetherwick to the top of Middle Temple Lane, found a taxi-cab within five minutes, and proposed himself to sit up and shakedown that night and the next, if necessary.
 
"Scent's getting hot, I think, sir," he remarked as they drove off, after bidding the driver carry them to Paddington Green. "Things seem to be coming to a head."
 
"Yes—but I don't think you know everything," answered Hetherwick. He proceeded to give the clerk an epitomised account of the day's doings as they had related to himself, concluding with Matherfield's theory as expressed after leaving the Green Archer. "You're a smart chap, Mapperley," he added. "What do you think?"
 
"I see Matherfield's point," answered Mapperley. "I can follow his line. He thinks like this: Hannaford, when he came to London, wanted to get rid, advantageously, of that formula of his about a new ink. He got into touch with Ambrose, whom, of course, he'd known before at Sellithwaite. Ambrose introduced him to some men who deal or dabble in chemicals, of whom one, no doubt, is Baseverie, and who seem to have a laboratory or something of that sort somewhere in the Westminster district. On the night of the murder Ambrose met Hannaford, by appointment, at Victoria, and took him there. Probably, Hannaford left the sealed packet—opened by that time—with these fellows. Probably, too, while there he told them—jokingly, very likely—what he'd discovered, from the picture in the papers, about the identity of Mrs. Whittingham and Madame Listorelle. And now comes in—Granett!"
 
Hetherwick gave an exclamation that denoted two or three things—surprise, for one.
 
"Ah!" he said. "Granett! To be sure! I'd forgotten Granett!"
 
"I hadn't," remarked Mapperley with a cynical laugh. "Granett—and his murder—is an essential factor. What I think is this: We know that Hannaford met Ambrose at Victoria Station that all-important evening. Ambrose, without doubt, took him to the place I hinted at just now—the exact location of which is a mystery. I think Hannaford stopped there until late in the evening. But—I also think he went back again! With—Granett!"
 
"Ah!" exclaimed Hetherwick. "I see!"
 
"We know," continued Mapperley, "that Granett went that evening to see the chemist who gave information about him; we know, too, that he and ............