“H’m!” said Dunbar, “you are a loss to the detective service, my lad!  And how do you account for the fact that Brian has not got to hear of the inquiry?”

Hamper bent to Dunbar and whispered, beerily, in his ear:  “P’r’aps ’e don’t want to ’ear, guv’nor!”

“Oh!  Why not?”

“Well, ’e knows there’s something up there!”

“Therefore it’s his plain duty to assist the police.”

“Same as what I does?” cried Hamper, raising his eyebrows.  “Course it is! but ’ow d’you know ’e ain’t been got at?”

“Our friend, here, evidently has one up against Mr. Tom Brian!” muttered Dunbar aside to Sowerby.

“Wotcher say, guv’nor?” inquired the cabman, looking from one to the other.

“I say, no doubt you can save us the trouble of looking out Brian’s license, and give us his private address?” replied Dunbar.

“Course I can.  ’E lives hat num’er 36 Forth Street, Brixton, and ’e’s out o’ the big Brixton depot.”

“Oh!” said Dunbar, dryly.  “Does he owe you anything?”

“Wotcher say, guv’nor?”

“I say, it’s very good of you to take all this trouble and whatever it has cost you in time, we shall be pleased to put right.”

Mr. Hamper spat in his right palm, and rubbed his hands together, appreciatively.

“Make it five bob!” he said.

“Wait downstairs,” directed Dunbar, pressing a bell-push beside the door.  “I’ll get it put through for you.”

“Right ’o!” rumbled the cabman, and went lurching from the room as a constable in uniform appeared at the door.  “Good mornin’, guv’nor.  Good mornin’!”

The cabman having departed, leaving in his wake a fragrant odor of fourpenny ale:—­

“Here you are, Sowerby!” cried Dunbar.  “We are moving at last!  This is the address of the late Mrs. Vernon’s maid.  See her; feel your ground, carefully, of course; get to know what clothes Mrs. Vernon took with her on her periodical visits to Scotland.”

“What clothes?”

“That’s the idea; it is important.  I don’t think the girl was in her mistress’s confidence, but I leave it to you to find out.  If circumstances point to my surmise being inaccurate—­you know how to act.”

“Just let me glance over your notes, bearing on the matter,” said Sowerby, “and I’ll be off.”

Dunbar handed him the bulging notebook, and Sergeant Sowerby lowered his inadequate eyebrows, thoughtfully, whilst he scanned the evidence of Mr. Debnam.  Then, returning the book to his superior, and adjusting the peculiar bowler firmly upon his head, he set out.

Dunbar glanced through some papers—­apparently reports—­which lay upon the table, penciled comments upon two of them, and then, consulting his notebook once more in order to refresh his memory, started off for Forth Street, Brixton.

Forth Street, Brixton, is a depressing thoroughfare.  It contains small, cheap flats, and a number of frowsy looking houses which give one the impression of having run to seed.  A hostelry of sad aspect occupies a commanding position midway along the street, but inspires the traveler not with cheer, but with lugubrious reflections upon the horrors of inebriety.  The odors, unpleasantly mingled, of fried bacon and paraffin oil, are wafted to the wayfarer from the porches of these family residences.